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Sample records for apoplastic water flow

  1. Papaya pulp gelling: is it premature ripening or problems of water accumulation in the apoplast?

    Directory of Open Access Journals (Sweden)

    Jurandi Gonçalves de Oliveira

    Full Text Available Gelled aspect in papaya fruit is typically confused with premature ripening. This research reports the characterization of this physiological disorder in the pulp of papaya fruit by measuring electrolyte leakage, Pi content, lipid peroxidation, pulp firmness, mineral contents (Ca, Mg and K - in pulp and seed tissues, and histological analysis of pulp tissue. The results showed that the gelled aspect of the papaya fruit pulp is not associated with tissue premature ripening. Data indicate a reduction of the vacuole water intake as the principal cause of the loss of cellular turgor; while the waterlogged aspect of the tissue may be due to water accumulation in the apoplast.

  2. Regulation of Water Deficit-Induced Abscisic Acid Accumulation by Apoplastic Ascorbic Acid in Maize Seedlings

    Institute of Scientific and Technical Information of China (English)

    Jian-Fang HU; Gui-Fen LI; Zhi-Hui GAO; Lin CHEN; Hui-Bo REN; Wen-Suo JIA

    2005-01-01

    Water deficit-induced abscisic acid (ABA) accumulation is one of the most important stress signaling pathways in plant cells. Redox regulation of cellular signaling has currently attracted particular attention, but much less is known about its roles and mechanisms in plant signaling. Herein, we report that water deficit-induced ABA accumulation could be regulated by ascorbic acid (AA)-controlled redox status in leave apoplast. The AA content in non-stressed leaves was approximately 3 μmol/g FW, corresponding to a mean concentration of 3 mmol/L in a whole cell. Because AA is mainly localized in the cytosol and chloroplasts, the volume of which is much smaller than that of the whole cell, AA content in cytosolic and chloroplast compartments should be much higher than 3 mmol/L. Water deficit-induced ABA accumulation in both leaf and root tissues of maize seedlings was significantly inhibited by AA and reduced glutathione (GSH) at concentrations of 500 μmol/L and was completely blocked by 50 mmol/L AA and GSH. These results suggest that the AA-induced inhibition of ABA accumulation should not occur at sites where AA exists in high concentrations. Although water deficit led to a small increase in the dehydroascorbic acid (DHA) content, no significant changes in AA content were observed in either leaf or root tissues. When compared with the whole leaf cell, the AA content in the apoplastic compartment was much lower (i.e.approximately 70 nmol/g FW, corresponding to 0.7 mmol/L). Water deficit induced a significant decrease (approximately 2.5-fold) in the AA content and an increase (approximately 3.4-fold) in the DHA content in the apoplastic compartment, thus leading to a considerably decreased redox status there, which may have contributed to the relief of AA-induced inhibition of ABA accumulation, alternatively, promoting water deficit-induced ABA accumulation. Reactive oxygen species (ROS) could not mimic water deficit in inducing ABA accumulation, suggesting that

  3. Freezing avoidance by supercooling in Olea europaea cultivars: the role of apoplastic water, solute content and cell wall rigidity.

    Science.gov (United States)

    Arias, Nadia S; Bucci, Sandra J; Scholz, Fabian G; Goldstein, Guillermo

    2015-10-01

    Plants can avoid freezing damage by preventing extracellular ice formation below the equilibrium freezing temperature (supercooling). We used Olea europaea cultivars to assess which traits contribute to avoid ice nucleation at sub-zero temperatures. Seasonal leaf water relations, non-structural carbohydrates, nitrogen and tissue damage and ice nucleation temperatures in different plant parts were determined in five cultivars growing in the Patagonian cold desert. Ice seeding in roots occurred at higher temperatures than in stems and leaves. Leaves of cold acclimated cultivars supercooled down to -13 °C, substantially lower than the minimum air temperatures observed in the study site. During winter, leaf ice nucleation and leaf freezing damage (LT50 ) occurred at similar temperatures, typical of plant tissues that supercool. Higher leaf density and cell wall rigidity were observed during winter, consistent with a substantial acclimation to sub-zero temperatures. Larger supercooling capacity and lower LT50 were observed in cold-acclimated cultivars with higher osmotically active solute content, higher tissue elastic adjustments and lower apoplastic water. Irreversible leaf damage was only observed in laboratory experiments at very low temperatures, but not in the field. A comparative analysis of closely related plants avoids phylogenetic independence bias in a comparative study of adaptations to survive low temperatures.

  4. Effects of root medium pH on root water transport and apoplastic pH in red-osier dogwood (Cornus sericea) and paper birch (Betula papyrifera) seedlings.

    Science.gov (United States)

    Zhang, W; Zwiazek, J J

    2016-11-01

    Soil pH is a major factor affecting plant growth. Plant responses to pH conditions widely vary between different species of plants. However, the exact mechanisms of high pH tolerance of plants are largely unknown. In the present study, we compared the pH responses of paper birch (Betula papyrifera) seedlings, a relatively sensitive species to high soil pH, with red-osier dogwood (Cornus sericea), reported to be relatively tolerant of high pH conditions. We examined the hypotheses that tolerance of plants to high root zone pH is linked to effective control of root apoplastic pH to facilitate nutrient and water transport processes In the study, we exposed paper birch and red-osier dogwood seedlings for six weeks to pH 5, 7 and 9 under controlled-environment conditions in hydroponic culture. Then, we measured biomass, gas exchange, root hydraulic conductivity, ferric chelate reductase (FCR) activity, xylem sap pH and the relative abundance of major elements in leaf protoplasts and apoplasts. The study sheds new light on the rarely studied high pH tolerance mechanisms in plants. We found that compared with paper birch, red-osier dogwood showed greater growth, higher gas exchange, and maintained higher root hydraulic conductivity as well as lower xylem sap pH under high pH conditions. The results suggest that the relatively high pH tolerance of dogwood is associated with greater water uptake ability and maintenance of low apoplastic pH. These traits may have a significant impact on the uptake of Fe and Mn by leaf cells.

  5. Chloride-inducible transient apoplastic alkalinizations induce stomata closure by controlling abscisic acid distribution between leaf apoplast and guard cells in salt-stressed Vicia faba.

    Science.gov (United States)

    Geilfus, Christoph-Martin; Mithöfer, Axel; Ludwig-Müller, Jutta; Zörb, Christian; Muehling, Karl H

    2015-11-01

    Chloride stress causes the leaf apoplast transiently to alkalize, an event that is presumed to contribute to the ability of plants to adapt to saline conditions. However, the initiation of coordinated processes downstream of the alkalinization is unknown. We hypothesize that chloride-inducible pH dynamics are a key chemical feature modulating the compartmental distribution of abscisic acid (ABA) and, as a consequence, affecting stomata aperture. Apoplastic pH and stomata aperture dynamics in intact Vicia faba leaves were monitored by microscopy-based ratio imaging and porometric measurements of stomatal conductance. ABA concentrations in leaf apoplast and guard cells were compared with pH dynamics by gas-chromatography-mass-spectrometry (GC-MS) and liquid-chromatography-tandem-mass spectrometry (LC-MS/MS). Results demonstrate that, upon chloride addition to roots, an alkalizing factor that initiates the pH dynamic propagates from root to leaf in a way similar to xylem-distributed water. In leaves, it induces a systemic transient apoplastic alkalinization that causes apoplastic ABA concentration to increase, followed by an elevation of endogenous guard cell ABA. We conclude that the transient alkalinization, which is a remote effect of chloride stress, modulates the compartmental distribution of ABA between the leaf apoplast and the guard cells and, in this way, is instrumental in inducing stomata closure during the beginning of salinity.

  6. Apoplast proteome reveals that extracellular matrix contributes to multistress response in poplar

    Directory of Open Access Journals (Sweden)

    Lawrence Amanda M

    2010-11-01

    Full Text Available Abstract Background Riverine ecosystems, highly sensitive to climate change and human activities, are characterized by rapid environmental change to fluctuating water levels and siltation, causing stress on their biological components. We have little understanding of mechanisms by which riverine plant species have developed adaptive strategies to cope with stress in dynamic environments while maintaining growth and development. Results We report that poplar (Populus spp. has evolved a systems level "stress proteome" in the leaf-stem-root apoplast continuum to counter biotic and abiotic factors. To obtain apoplast proteins from P. deltoides, we developed pressure-chamber and water-displacement methods for leaves and stems, respectively. Analyses of 303 proteins and corresponding transcripts coupled with controlled experiments and bioinformatics demonstrate that poplar depends on constitutive and inducible factors to deal with water, pathogen, and oxidative stress. However, each apoplast possessed a unique set of proteins, indicating that response to stress is partly compartmentalized. Apoplast proteins that are involved in glycolysis, fermentation, and catabolism of sucrose and starch appear to enable poplar to grow normally under water stress. Pathogenesis-related proteins mediating water and pathogen stress in apoplast were particularly abundant and effective in suppressing growth of the most prevalent poplar pathogen Melampsora. Unexpectedly, we found diverse peroxidases that appear to be involved in stress-induced cell wall modification in apoplast, particularly during the growing season. Poplar developed a robust antioxidative system to buffer oxidation in stem apoplast. Conclusion These findings suggest that multistress response in the apoplast constitutes an important adaptive trait for poplar to inhabit dynamic environments and is also a potential mechanism in other riverine plant species.

  7. Proteomic analyses of apoplastic proteins from germinating Arabidopsis thaliana pollen

    OpenAIRE

    Ge, Weina; Song, Yun; Zhang, Cuijun; Zhang, Yafang; Burlingame, Alma L; Guo, Yi

    2011-01-01

    Pollen grains play important roles in the reproductive processes of flowering plants. The roles of apoplastic proteins in pollen germination and in pollen tube growth are comparatively less well understood. To investigate the functions of apoplastic proteins in pollen germination, the global apoplastic proteins of mature and germinated Arabidopsis thaliana pollen grains were prepared for differential analyses by using 2-dimensional fluorescence difference gel electrophoresis (2-D DIGE) satura...

  8. Water flow through temperate glaciers

    Science.gov (United States)

    Fountain, A.G.; Walder, J.S.

    1998-01-01

    Understanding water movement through a glacier is fundamental to several critical issues in glaciology, including glacier dynamics, glacier-induced floods, and the prediction of runoff from glacierized drainage basins. to this end we have synthesized a conceptual model os water movement through a temperate glacier from the surface to the outlet stream. Processes that regulate the rate and distribution of water input at the glacier surface and that regulate water movement from the surface to the bed play important but commonly neglected roles in glacier hydrology. Where a glacier is covered by a layer of porous, permeable firn (the accumulation zone), the flux of water to the glacier interior varies slowly because the firn temporarily stores water and thereby smooths out variations in the supply rate. In the firn-free ablation zone, in contrast, the flux of water into the glacier depends directly on the rate of surface melt or rainfall and therefore varies greatly in time. Water moves from the surface to the bed through an upward branching arborescent network consisting of both steeply inclined conduits, formed by the enlargement of intergranular veins, and gently inclined conduits, sprqwned by water flow along the bottoms of near-surface fractures (crevasses). Englacial drainage conduits deliver water to the glacier bed at a linited number of points, probably a long distance downglacier of where water enters the glacier. Englacial conduits supplied from the accumulation zone are quasi steady state features that convey the slowly varying water flux delivered via the firn. their size adjusts so that they are usually full of water and flow is pressurized. In contrast, water flow in englacial conduits supplied from the ablation area is pressurized only near times of peak daily flow or during rainstorms; flow is otherwise in an open-channel configuration. The subglacial drainage system typically consists of several elements that are distinct both morpphologically and

  9. Apoplastic and symplastic solute concentrations contribute to osmotic adjustment in bean genotypes during drought stress

    OpenAIRE

    GÜLER, Neslihan SARUHAN; SAĞLAM, Aykut; DEMİRALAY, Mehmet; KADIOĞLU, Asım

    2012-01-01

    The present study investigates changes in the inorganic ions, proline, and endogenous abscisic acid (ABA) contents of the apoplastic and symplastic compartments of leaves from drought-tolerant (Yakutiye) and drought-sensitive (Zulbiye) cultivars of the common bean (Phaseolus vulgaris L.). Drought stress caused a decrease in leaf water potential and stomatal conductance in both cultivars. Concentrations of proline in the drought-tolerant and drought-sensitive cultivars increased in response to...

  10. The maize cystatin CC9 interacts with apoplastic cysteine proteases.

    Science.gov (United States)

    van der Linde, Karina; Mueller, André N; Hemetsberger, Christoph; Kashani, Farnusch; van der Hoorn, Renier A L; Doehlemann, Gunther

    2012-11-01

    In a recent study we identified corn cystain9 (CC9) as a novel compatibility factor for the interaction of the biotrophic smut fungus Ustilago maydis with its host plant maize. CC9 is transcriptionally induced during the compatible interaction with U. maydis and localizes in the maize apoplast where it inhibits apoplastic papain-like cysteine proteases. The proteases are activated during incompatible interaction and salicylic acid (SA) treatment and, in turn, are sufficient to induce SA signaling including PR-gene expression. Therefore the inhibition of apoplastic papain-like cysteine proteases by CC9 is essential to suppress host immunity during U. maydis infection. Here were present new experimental data on the cysteine protease-cystatin interaction and provide an in silco analysis of plant cystatins and the identified apoplastic cysteine proteases.

  11. Fluid dynamics: Water flows out of touch

    Science.gov (United States)

    Hof, Björn

    2017-01-01

    Superhydrophobic surfaces reduce the frictional drag between water and solid materials, but this effect is often temporary. The realization of sustained drag reduction has applications for water vehicles and pipeline flows.

  12. Apoplastic interactions between plants and plant root intruders

    Directory of Open Access Journals (Sweden)

    Kanako eMitsumasu

    2015-08-01

    Full Text Available Numerous pathogenic or parasitic organisms attack plant roots to obtain nutrients, and the apoplast including the plant cell wall is where the plant cell meets such organisms. Root-parasitic angiosperms and nematodes are two distinct types of plant root parasites but share some common features in their strategies for breaking into plant roots. Striga and Orobanche are obligate root parasitic angiosperms that cause devastating agricultural problems worldwide. Parasitic plants form an invasion organ called a haustorium, where plant cell wall degrading enzymes (PCWDEs are highly expressed. Plant-parasitic nematodes are another type of agriculturally important plant root parasite. These nematodes breach the plant cell walls by protruding a sclerotized stylet from which PCWDEs are secreted. Responding to such parasitic invasion, host plants activate their own defense responses against parasites. Endoparasitic nematodes secrete apoplastic effectors to modulate host immune responses and to facilitate the formation of a feeding site. Apoplastic communication between hosts and parasitic plants also contributes to their interaction. Parasitic plant germination stimulants, strigolactones (SLs, are recently identified apoplastic signals that are transmitted over long distances from biosynthetic sites to functioning sites. Here, we discuss recent advances in understanding the importance of apoplastic signals and cell walls for plant-parasite interactions.

  13. Apoplastic interactions between plants and plant root intruders.

    Science.gov (United States)

    Mitsumasu, Kanako; Seto, Yoshiya; Yoshida, Satoko

    2015-01-01

    Numerous pathogenic or parasitic organisms attack plant roots to obtain nutrients, and the apoplast including the plant cell wall is where the plant cell meets such organisms. Root parasitic angiosperms and nematodes are two distinct types of plant root parasites but share some common features in their strategies for breaking into plant roots. Striga and Orobanche are obligate root parasitic angiosperms that cause devastating agricultural problems worldwide. Parasitic plants form an invasion organ called a haustorium, where plant cell wall degrading enzymes (PCWDEs) are highly expressed. Plant-parasitic nematodes are another type of agriculturally important plant root parasite. These nematodes breach the plant cell walls by protruding a sclerotized stylet from which PCWDEs are secreted. Responding to such parasitic invasion, host plants activate their own defense responses against parasites. Endoparasitic nematodes secrete apoplastic effectors to modulate host immune responses and to facilitate the formation of a feeding site. Apoplastic communication between hosts and parasitic plants also contributes to their interaction. Parasitic plant germination stimulants, strigolactones, are recently identified apoplastic signals that are transmitted over long distances from biosynthetic sites to functioning sites. Here, we discuss recent advances in understanding the importance of apoplastic signals and cell walls for plant-parasite interactions.

  14. Estimated Water Flows in 2005: United States

    Energy Technology Data Exchange (ETDEWEB)

    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.

  15. Ground-water flow related to streamflow and water quality

    Science.gov (United States)

    Van Voast, W. A.; Novitzki, R.P.

    1968-01-01

    A ground-water flow system in southwestern Minnesota illustrates water movement between geologic units and between the land surface and the subsurface. The flow patterns indicate numerous zones of ground-water recharge and discharge controlled by topography, varying thicknesses of geologic units, variation in permeabilities, and the configuration of the basement rock surface. Variations in streamflow along a reach of the Yellow Medicine River agree with the subsurface flow system. Increases and decreases in runoff per square mile correspond, apparently, to ground-water discharge and recharge zones. Ground-water quality variations between calcium sulfate waters typical of the Quaternary drift and sodium chloride waters typical of the Cretaceous rocks are caused by mixing of the two water types. The zones of mixing are in agreement with ground-water flow patterns along the hydrologic section.

  16. Apoplast as the site of response to environmental signals.

    Science.gov (United States)

    Hoson, T

    1998-03-01

    When the life cycle of plants is influenced by various environmental signals, the mechanical properties of the cell wall are greatly changed. These signals also modify the levels and structure of the cell wall constituents and such modifications are supposed to be the cause of the changes in the wall mechanical properties. These changes in the cell wall, the major component of the apoplast, can be recognized as the response of plants to environmental signals. The analysis of the mechanism leading to the response suggests that the apoplast is involved not only in the response but also in the perception and transduction of environmental signals in concert with the receptors of signals located on the plasma membrane. Thus, the apoplast plays a principal role in the communication of plants with the outer world and enables the plants to adapt themselves and survive in the environment full of stresses.

  17. Ground Water Flow No Longer A Mystery

    Science.gov (United States)

    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)

  18. Morphometric methods for simulation of water flow.

    NARCIS (Netherlands)

    Booltink, H.W.G.

    1993-01-01

    Water flow in structured soils is strongly governed by the occurence of macropores. In this study emphasis was given to combined research of morphology of water- conducting macropores and soil physical measurements on bypass flow. Main research objectives were to: (i) develop and improve soil physic

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

    Directory of Open Access Journals (Sweden)

    T. Erfani

    2014-03-01

    Full Text Available 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.

  20. Drag Reduction in Oil-water Flows

    OpenAIRE

    Edomwonyi-Otu, L. C.

    2015-01-01

    Liquid-liquid flows occur in many chemical and process industries including the petroleum industry where crude oil and its derivatives are transported over long distances often in mixtures with water. Depending on flow conditions and pipe geometry different flow patterns can appear ranging from fully separated to dispersed ones. The addition of small amounts of some polymeric materials to one of the phases has been found to change the flow patterns and their boundaries and reduce the friction...

  1. Plant natriuretic peptides are apoplastic and paracrine stress response molecules

    KAUST Repository

    Wang, Yuhua

    2011-04-07

    Higher plants contain biologically active proteins that are recognized by antibodies against human atrial natriuretic peptide (ANP). We identified and isolated two Arabidopsis thaliana immunoreactive plant natriuretic peptide (PNP)-encoding genes, AtPNP-A and AtPNP-B, which are distantly related members of the expansin superfamily and have a role in the regulation of homeostasis in abiotic and biotic stresses, and have shown that AtPNP-A modulates the effects of ABA on stomata. Arabidopsis PNP (PNP-A) is mainly expressed in leaf mesophyll cells, and in protoplast assays we demonstrate that it is secreted using AtPNP-A:green fluorescent protein (GFP) reporter constructs and flow cytometry. Transient reporter assays provide evidence that AtPNP-A expression is enhanced by heat, osmotica and salt, and that AtPNP-A itself can enhance its own expression, thereby generating a response signature diagnostic for paracrine action and potentially also autocrine effects. Expression of native AtPNP-A is enhanced by osmotica and transiently by salt. Although AtPNP-A expression is induced by salt and osmotica, ABA does not significantly modulate AtPNP-A levels nor does recombinant AtPNP-A affect reporter expression of the ABA-responsive RD29A gene. Together, these results provide experimental evidence that AtPNP-A is stress responsive, secreted into the apoplastic space and can enhance its own expression. Furthermore, our findings support the idea that AtPNP-A, together with ABA, is an important component in complex plant stress responses and that, much like in animals, peptide signaling molecules can create diverse and modular signals essential for growth, development and defense under rapidly changing environmental conditions. © 2011 The Author.

  2. Proteomic analyses of apoplastic proteins from germinating Arabidopsis thaliana pollen.

    Science.gov (United States)

    Ge, Weina; Song, Yun; Zhang, Cuijun; Zhang, Yafang; Burlingame, Alma L; Guo, Yi

    2011-12-01

    Pollen grains play important roles in the reproductive processes of flowering plants. The roles of apoplastic proteins in pollen germination and in pollen tube growth are comparatively less well understood. To investigate the functions of apoplastic proteins in pollen germination, the global apoplastic proteins of mature and germinated Arabidopsis thaliana pollen grains were prepared for differential analyses by using 2-dimensional fluorescence difference gel electrophoresis (2-D DIGE) saturation labeling techniques. One hundred and three proteins differentially expressed (p value≤0.01) in pollen germinated for 6h compared with un-germination mature pollen, and 98 spots, which represented 71 proteins, were identified by LC-MS/MS. By bioinformatics analysis, 50 proteins were identified as secreted proteins. These proteins were mainly involved in cell wall modification and remodeling, protein metabolism and signal transduction. Three of the differentially expressed proteins were randomly selected to determine their subcellular localizations by transiently expressing YFP fusion proteins. The results of subcellular localization were identical with the bioinformatics prediction. Based on these data, we proposed a model for apoplastic proteins functioning in pollen germination and pollen tube growth. These results will lead to a better understanding of the mechanisms of pollen germination and pollen tube growth.

  3. Nanedi Vallis: Sustained Water FLow?

    Science.gov (United States)

    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.

  4. Water slip flow in superhydrophobic microtubes within laminar flow region

    Institute of Scientific and Technical Information of China (English)

    Zhijia Yu; Xinghua Liu; Guozhu Kuang

    2015-01-01

    The fabrication of superhydrophobic surfaces and the studies on water flow characteristics therein are of great significance to many industrial areas as wel as to science and technology development. Experiments were car-ried out to investigate slip characteristics of water flowing in circular superhydrophobic microtubes within lam-inar flow region. The superhydrophobic microtubes of stainless steel were fabricated with chemical etching–fluorination treatment. An experimental setup was designed to measure the pressure drop as function of water flow rate. For comparison, superhydrophilic tubes were also tested. Poiseuille number Po was found to be smaller for the superhydrophobic microtubes than that for superhydrophilic ones. The pressure drop reduc-tion ranges from 8%to 31%. It decreases with increasing Reynolds number when Re b 900, owing to the transition from Cassie state to Wenzel state. However, it is almost unchanged with further increasing Re after Re N 900. The slip length in superhydrophobic microtubes also exhibits a Reynolds number dependence similarly to the pressure drop reduction. The relation between slip length and Darcy friction factor is theoretically analyzed with consideration of surface roughness effect, which was testified with the experimental results.

  5. Roles of apoplastic peroxidases in plant response to wounding.

    Science.gov (United States)

    Minibayeva, Farida; Beckett, Richard Peter; Kranner, Ilse

    2015-04-01

    Apoplastic class III peroxidases (EC 1.11.1.7) play key roles in the response of plants to pathogen infection and abiotic stresses, including wounding. Wounding is a common stress for plants that can be caused by insect or animal grazing or trampling, or result from agricultural practices. Typically, mechanical damage to a plant immediately induces a rapid release and activation of apoplastic peroxidases, and an oxidative burst of reactive oxygen species (ROS), followed by the upregulation of peroxidase genes. We discuss how plants control the expression of peroxidases genes upon wounding, and also the sparse information on peroxidase-mediated signal transduction pathways. Evidence reviewed here suggests that in many plants production of the ROS that comprise the initial oxidative burst results from a complex interplay of peroxidases with other apoplastic enzymes. Later responses following wounding include various forms of tissue healing, for example through peroxidase-dependent suberinization, or cell death. Limited data suggest that ROS-mediated death signalling during the wound response may involve the peroxidase network, together with other redox molecules. In conclusion, the ability of peroxidases to both generate and scavenge ROS plays a key role in the involvement of these enigmatic enzymes in plant stress tolerance.

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

    Science.gov (United States)

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

    2016-04-05

    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.

  7. Responses of prawn to water flow rates

    Energy Technology Data Exchange (ETDEWEB)

    Vascotto, G.L.; Nilas, P.U.

    1987-05-28

    An aquarium study to determine the responses of postlarval macrobrachium rosenbergii to varying water changes was carried out. Six week old postlarvae were raised in glass aquaria receiving 0, 1.15, 7.2 and 14.4 water changes per day over a 12 week period. The treatments had significant influences on survival, biomass, and average size of the animals. Maximum survival and highest biomass were found in the 1.15 water turnover treatment; however, this treatment also produced the smallest average size animals. Early high mortalities were attributed to poor growing conditions in the high and low flow treatments, while later mortality appeared to be biomass dependent.

  8. Water flow and solute transport in the soil-plant-atmosphere continuum: Upscaling from rhizosphere to root zone

    Science.gov (United States)

    Lazarovitch, Naftali; Perelman, Adi; Guerra, Helena; Vanderborght, Jan; Pohlmeier, Andreas

    2016-04-01

    Root water and nutrient uptake are among the most important processes considered in numerical models simulating water content and fluxes in the subsurface, as they control plant growth and production as well as water flow and nutrient transport out of the root zone. Root water uptake may lead to salt accumulation at the root-soil interface, resulting in rhizophere salt concentrations much higher than in the bulk soil. This salt accumulation is caused by soluble salt transport towards the roots by mass flow through the soil, followed by preferential adsorption of specific nutrients by active uptake, thereby excluding most other salts at the root-soil interface or in the root apoplast. The salinity buildup can lead to large osmotic pressure gradients across the roots thereby effectively reducing root water uptake. The initial results from rhizoslides (capillary paper growth system) show that sodium concentration is decreasing with distance from the root, compared with the bulk that remained more stable. When transpiration rate was decreased under high salinity levels, sodium concentration was more homogenous compared with low salinity levels. Additionally, sodium and gadolinium distributions were measured nondestructively around tomato roots using magnetic resonance imaging (MRI). This technique could also observe the root structure and water content around single roots. Results from the MRI confirm the solutes concentration pattern around roots and its relation to their initial concentration. We conclude that local water potentials at the soil-root interface differ from bulk potentials. These relative differences increase with decreasing root density, decreasing initial salt concentration and increasing transpiration rate. Furthermore, since climate may significantly influence plant response to salinity a dynamic climate-coupled salinity reduction functions are critical in while using macroscopic numerical models.

  9. Air-water flow in subsurface systems

    Science.gov (United States)

    Hansen, A.; Mishra, P.

    2013-12-01

    Groundwater traces its roots to tackle challenges of safe and reliable drinking water and food production. When the groundwater level rises, air pressure in the unsaturated Vadose zone increases, forcing air to escape from the ground surface. Abnormally high and low subsurface air pressure can be generated when the groundwater system, rainfall, and sea level fluctuation are favorably combined [Jiao and Li, 2004]. Through this process, contamination in the form of volatile gases may diffuse from the ground surface into residential areas, or possibly move into groundwater from industrial waste sites. It is therefore crucial to understand the combined effects of air-water flow in groundwater system. Here we investigate theoretically and experimentally the effects of air and water flow in groundwater system.

  10. Association between photosynthesis and contrasting features of minor veins in leaves of summer annuals loading phloem via symplastic versus apoplastic routes.

    Science.gov (United States)

    Muller, Onno; Cohu, Christopher M; Stewart, Jared J; Protheroe, Johanna A; Demmig-Adams, Barbara; Adams, William W

    2014-09-01

    Foliar vascular anatomy and photosynthesis were evaluated for a number of summer annual species that either load sugars into the phloem via a symplastic route (Cucumis sativus L. cv. Straight Eight; Cucurbita pepo L. cv. Italian Zucchini Romanesco; Citrullus lanatus L. cv. Faerie Hybrid; Cucurbita pepo L. cv. Autumn Gold) or an apoplastic route (Nicotiana tabacum L.; Solanum lycopersicum L. cv. Brandywine; Gossypium hirsutum L.; Helianthus annuus L. cv. Soraya), as well as winter annual apoplastic loaders (Spinacia oleracea L. cv. Giant Nobel; Arabidopsis thaliana (L.) Heynhold Col-0, Swedish and Italian ecotypes). For all summer annuals, minor vein cross-sectional xylem area and tracheid number as well as the ratio of phloem loading cells to phloem sieve elements, each when normalized for foliar vein density (VD), was correlated with photosynthesis. These links presumably reflect (1) the xylem's role in providing water to meet foliar transpirational demand supporting photosynthesis and (2) the importance of the driving force of phloem loading as well as the cross-sectional area for phloem sap flux to match foliar photosynthate production. While photosynthesis correlated with the product of VD and cross-sectional phloem cell area among symplastic loaders, photosynthesis correlated with the product of VD and phloem cell number per vein among summer annual apoplastic loaders. Phloem cell size has thus apparently been a target of selection among symplastic loaders (where loading depends on enzyme concentration within loading cells) versus phloem cell number among apoplastic loaders (where loading depends on membrane transporter numbers).

  11. Case study on ground water flow (8)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-02-01

    The report comprises research activities made in fiscal year 1997 under the contract of Japan Nuclear Fuel Cycle Development Center and the main items are: (1) Evaluation of water permeability through discontinuous hard bedrock in deep strata in relevant with underground disposal of radioactive wastes, (2) Three dimensional analysis of permeated water in bedrock, including flow analysis in T ono district using neuro-network and modification of Evaporation Logging System, (3) Development of hydraulic tests and necessary equipment applicable to measurements of complex dielectric constants of contaminated soils using FUDR-V method, this giving information on soil component materials, (4) Investigation methods and modeling of hydraulics in deep strata, (5) Geological study of ground water using environmental isotopes such as {sup 14}C, {sup 36}Cl and {sup 4}He, particularly measurement of ages of ground water using an accelerator-mass spectrometer, and (6) Re-submerging phenomena affecting the long-term geological stability. (S. Ohno)

  12. Stability of people exposed to water flows

    Directory of Open Access Journals (Sweden)

    E. Martínez-Gomariz

    2016-01-01

    Full Text Available Our cities are formed by several elements which are exposed to floods of a magnitude according to the importance of the rainfall event and the design of the urban drainage system. The most important components in the cities are the pedestrians who develop various activities during rain events. Focusing on pedestrians, the research on their stability when they are exposed to water flows provides the necessary knowledge to understand and manage the associated hazard for them. In this research, several experiments with humans were carried out in order to determine the stability limits to pedestrians crossing through a water flow in a real scale platform. The results obtained and by comparing those with human stability criteria proposed by other authors and guidelines provide a more restrictive criterion.

  13. Collection of apoplastic fluids from Arabidopsis thaliana leaves

    DEFF Research Database (Denmark)

    Madsen, Svend Roesen; Nour-Eldin, Hussam Hassan; Halkier, Barbara Ann

    2016-01-01

    The leaf apoplast comprises the extracellular continuum outside cell membranes. A broad range of processes take place in the apoplast, including intercellular signaling, metabolite transport, and plant-microbe interactions. To study these processes, it is essential to analyze the metabolite conte...

  14. An internal standard technique for improved quantitative analysis of apoplastic metabolites in tomato leaves

    Science.gov (United States)

    The purpose of this study was to establish a technique with sufficiently precision to monitor subtle changes in the concentration of apoplastic metabolites in tomato leaves. The plant apoplast is the site of the first line of defense against many foliar pathogens. This aqueous layer lining the air...

  15. Tracer injection techniques in flowing surface water

    Science.gov (United States)

    Wörman, A.

    2009-04-01

    Residence time distributions for flowing water and reactive matter are commonly used integrated properties of the transport process for determining technical issues of water resource management and in eco-hydrological science. Two general issues for tracer techniques are that the concentration-vs-time relation following a tracer injection (the breakthrough curve) gives unique transport information in different parts of the curve and separation of hydromechanical and reactive mechanisms often require simultaneous tracer injections. This presentation discusses evaluation methods for simultaneous tracer injections based on examples of tracer experiments in small rivers, streams and wetlands. Tritiated water is used as a practically inert substance to reflect the actual hydrodynamics, but other involved tracers are Cr(III)-51, P-32 and N-15. Hydromechanical, in-stream dispersion is reflected as a symmetrical spreading of the spatial concentration distribution. This requires that the transport distance over water depth is larger than about five times the flow Peclet number. Transversal retention of both inert and reactive solutes is reflected in terms of the tail of the breakthrough curve. Especially, reactive solutes can have a substantial magnification of the tailing behaviour depending on reaction rates or partitioning coefficients. To accurately discriminate between the effects of reactions and hydromechanical mixing its is relevant to use simultaneous injections of inert and reactive tracers with a sequential or integrated evaluation procedure. As an example, the slope of the P-32 tailing is consistently smaller than that of a simultaneous tritium injection in Ekeby wetland, Eskilstuna. The same applies to N-15 injected in the same experiment, but nitrogen is affected also by a systematic loss due to denitrification. Uptake in stream-bed sediments can be caused by a pumping effect arising when a variable pressure field is created on the stream bottom due to bed

  16. Self Calibrating Flow Estimation in Waste Water Pumping Stations

    DEFF Research Database (Denmark)

    Kallesøe, Carsten Skovmose; Knudsen, Torben

    2016-01-01

    Knowledge about where waste water is flowing in waste water networks is essential to optimize the operation of the network pumping stations. However, installation of flow sensors is expensive and requires regular maintenance. This paper proposes an alternative approach where the pumps and the waste...... water pit are used for estimating both the inflow and the pump flow of the pumping station. Due to the nature of waste water, the waste water pumps are heavily affected by wear and tear. To compensate for the wear of the pumps, the pump parameters, used for the flow estimation, are automatically...

  17. Water flow energy harvesters for autonomous flowmeters

    Science.gov (United States)

    Boisseau, Sebastien; Duret, Alexandre-Benoit; Perez, Matthias; Jallas, Emmanuel; Jallas, Eric

    2016-11-01

    This paper reports on a water flow energy harvester exploiting a horizontal axis turbine with distributed magnets of alternate polarities at the rotor periphery and air coils outside the pipe. The energy harvester operates down to 1.2L/min with an inlet section of 20mm of diameter and up to 25.2mW are provided at 20L/min in a 2.4V NiMH battery through a BQ25504 power management circuit. The pressure loss induced by the insertion of the energy harvester in the hydraulic circuit and by the extraction of energy has been limited to 0.05bars at 30L/min, corresponding to a minor loss coefficient of KEH=3.94.

  18. Water Modeling of Optimizing Tundish Flow Field

    Institute of Scientific and Technical Information of China (English)

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

    2007-01-01

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

  19. Response of antioxidative enzymes and apoplastic bypass transport in Thlaspi caerulescens and Raphanus sativus to cadmium stress.

    Science.gov (United States)

    Benzarti, Saoussen; Hamdi, Helmi; Mohri, Shino; Ono, Yoshiro

    2010-01-01

    A hydroponics experiment using hyperaccumulator Thlaspi caerulescens (alpine pennycress) and non-specific accumulator Raphanus sativus (common radish) was conducted to investigate the short-term effect of increasing Cd concentrations (0, 25, 50, 75, 100 microM) on metal uptake, chlorophyll content, antioxidative enzymes, and apoplastic bypass flow. As expected, T. caerulescens generally showed better resistance to metal stress, which was reflected by higher Cd accumulation within plant tissues with no signs of chlorosis, or wilt. Glutathione reductase (GR) and superoxide dismutase (SOD) activities in fresh leaves were monitored as the plant metal-detoxifying response. In general, both plant species exhibited an increase trend of GR activity before declining at 100 microM likely due to excessive levels of phytotoxic Cd. SOD activity exhibited almost a similar variation pattern to GR and decreased also at 100 microM Cd. For both plant species, fluorescent PTS uptake (8-hydroxy-1,3,6-pyrenetrisulphonic acid) increased significantly with metal level in exposure solutions indicating that Cd has a comparable effect to drought or salinity in terms of the gain of relative importance in apoplastic bypass transport under such stress conditions.

  20. Comparative evaluation of extraction methods for apoplastic proteins from maize leaves

    Directory of Open Access Journals (Sweden)

    Witzel Katja

    2011-12-01

    Full Text Available Abstract Proteins in the plant apoplast are essential for many physiological processes. We have analysed and compared six different infiltration solutions for proteins contained in the apoplast to recognize the most suitable method for leaves and to establish proteome maps for each extraction. The efficiency of protocols was evaluated by comparing the protein patterns resolved by 1-DE and 2-DE, and revealed distinct characteristics for each infiltration solution. Nano-LC-ESI-Q-TOF MS analysis of all fractions was applied to cover all proteins differentially extracted by infiltration solutions and led to the identification of 328 proteins in total in apoplast preparations. The predicted subcellular protein localisation distinguished the examined infiltration solutions in those with high or low amounts of intracellular protein contaminations, and with high or low quantities of secreted proteins. All tested infiltration solution extracted different subsets of proteins, and those implications on apoplast-specific studies are discussed.

  1. Apoplastic and intracellular plant sugars regulate developmental transitions in witches’ broom disease of cacao

    OpenAIRE

    Barau, Joan; GRANDIS, Adriana; Carvalho, Vinicius Miessler de Andrade; Teixeira, Gleidson Silva; Zaparoli, Gustavo Henrique Alcalá; do Rio, Maria Carolina Scatolin; Rincones, Johana; Buckeridge, Marcos Silveira; Pereira, Gonçalo Amarante Guimarães

    2014-01-01

    Witches’ broom disease (WBD) of cacao differs from other typical hemibiotrophic plant diseases by its unusually long biotrophic phase. Plant carbon sources have been proposed to regulate WBD developmental transitions; however, nothing is known about their availability at the plant–fungus interface, the apoplastic fluid of cacao. Data are provided supporting a role for the dynamics of soluble carbon in the apoplastic fluid in prompting the end of the biotrophic phase of infection. Carbon deple...

  2. Effects of ozone on apoplast/cytoplasm partitioning of ascorbic acid in snap bean

    Energy Technology Data Exchange (ETDEWEB)

    Burkey, K.O. [North Carolina State Univ., Dept. of Crop Science and Botany, Raleigh, NC (United States)

    1999-07-01

    Apoplast/cytoplasm partitioning of ascorbic acid (AA) was examined in four genotypes of snap bean (Phaseolus vulgaris L.) known to differ in ozone sensitivity. Plants were grown in pots under field conditions using open-top chambers to establish charcoal-filtered (CF) air (36 nmol mol{sup -1} ozone) or elevated ozone (77 nmol mol{sup -1} ozone) treatments, AA in fully expanded leaves of 36-day-old plants was separated into apoplast and cytoplasm fractions by vacuum infiltration methods using glucose 6-phosphate as a marker for cytoplasm contamination, Apoplast ascorbate levels ranged from 30 to 150 nmol g{sup -1} fresh weight. Ozone-sensitive genotypes partitioned 1-2% of total AA into the apoplast under CF conditions and up to 7% following a 7-day ozone exposure. In contrast, an ozone-tolerant genotype partitioned 3-4% of total leaf AA into the leaf apoplast in both CF and ozone-treated plants. The results suggest that genetic background and ozone stress are factors that affect AA levels in the extracellular space. For all genotypes, the fraction of AA in the oxidized form was higher in the apoplast compared to the cytoplasm, indicative of a more oxidizing environment within the cell wall. (au)

  3. RE-AERATION LAW OF WATER FLOW OVER SPILLWAYS

    Institute of Scientific and Technical Information of China (English)

    CHENG Xiang-ju; LUO Lin; CHEN Yong-can; ZHAO Wen-qian

    2006-01-01

    In order to explore the re-aeration law of water flow over spillway, the transfer process of oxygen in water flow over spillway was studied. The interfacial mass transfer coefficients were obtained by experiments. The flow fields and the turbulence characteristics are simulated by numerical methods. The fractional volume of fluid model (VOF) of the air-water two phase flows was introduced to track the interface. Consequently, the quantitative expression of the interfacial mass transfer coefficients related with velocity and kinetic energy at the free surface was derived and the re-aeration model for the water flow over spillway was established. The examination with the experimental data of different conditions shows the validity of the re-aeration model for the water flow over spillways. This study will be important to evaluate the dissolved oxygen concentration and self-purification ability of rivers.

  4. Revisiting Apoplastic Auxin Signaling Mediated by AUXIN BINDING PROTEIN 1.

    Science.gov (United States)

    Feng, Mingxiao; Kim, Jae-Yean

    2015-10-01

    It has been suggested that AUXIN BINDING PROTEIN 1 (ABP1) functions as an apoplastic auxin receptor, and is known to be involved in the post-transcriptional process, and largely independent of the already well-known SKP-cullin-F-box-transport inhibitor response (TIR1) /auxin signaling F-box (AFB) (SCF(TIR1/AFB)) pathway. In the past 10 years, several key components downstream of ABP1 have been reported. After perceiving the auxin signal, ABP1 interacts, directly or indirectly, with plasma membrane (PM)-localized transmembrane proteins, transmembrane kinase (TMK) or SPIKE1 (SPK1), or other unidentified proteins, which transfer the signal into the cell to the Rho of plants (ROP). ROPs interact with their effectors, such as the ROP interactive CRIB motif-containing protein (RIC), to regulate the endocytosis/exocytosis of the auxin efflux carrier PIN-FORMED (PIN) proteins to mediate polar auxin transport across the PM. Additionally, ABP1 is a negative regulator of the traditional SCF(TIR1/AFB) auxin signaling pathway. However, Gao et al. (2015) very recently reported that ABP1 is not a key component in auxin signaling, and the famous abp1-1 and abp1-5 mutant Arabidopsis lines are being called into question because of possible additional mutantion sites, making it necessary to reevaluate ABP1. In this review, we will provide a brief overview of the history of ABP1 research.

  5. Pumpage for the transient ground-water flow model, Death Valley regional ground-water flow system, Nevada and California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This digital data set represents ground-water discharged from the Death Valley regional ground-water flow system (DVRFS) through pumped wells. Pumping from wells in...

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

    Science.gov (United States)

    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.

  7. Study on an undershot cross-flow water turbine

    Science.gov (United States)

    Nishi, Yasuyuki; Inagaki, Terumi; Li, Yanrong; Omiya, Ryota; Fukutomi, Junichiro

    2014-06-01

    This study aims to develop a water turbine suitable for ultra-low heads in open channels, with the end goal being the effective utilization of unutilized hydroelectric energy in agricultural water channels. We performed tests by applying a cross-flow runner to an open channel as an undershot water turbine while attempting to simplify the structure and eliminate the casing. We experimentally investigated the flow fields and performance of water turbines in states where the flow rate was constant for the undershot cross-flow water turbine mentioned above. In addition, we compared existing undershot water turbines with our undershot cross-flow water turbine after attaching a bottom plate to the runner. From the results, we were able to clarify the following. Although the effective head for cross-flow runners with no bottom plate was lower than those found in existing runners equipped with a bottom plate, the power output is greater in the high rotational speed range because of the high turbine efficiency. Also, the runner with no bottom plate differed from runners that had a bottom plate in that no water was being wound up by the blades or retained between the blades, and the former received twice the flow due to the flow-through effect. As a result, the turbine efficiency was greater for runners with no bottom plate in the full rotational speed range compared with that found in runners that had a bottom plate.

  8. Nitrate does not result in iron inactivation in the apoplast of sunflower leaves.

    Science.gov (United States)

    Nikolic, Miroslav; Römheld, Volker

    2003-07-01

    It has been hypothesized that nitrate (NO(3)(-)) nutrition might induce iron (Fe) deficiency chlorosis by inactivation of Fe in the leaf apoplast (H.U. Kosegarten, B. Hoffmann, K. Mengel [1999] Plant Physiol 121: 1069-1079). To test this hypothesis, sunflower (Helianthus annuus L. cv Farnkasol) plants were grown in nutrient solutions supplied with various nitrogen (N) forms (NO(3)(-), NH(4)(+) and NH(4)NO(3)), with or without pH control by using pH buffers [2-(N-morpholino)ethanesulfonic acid or 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid]. It was shown that high pH in the nutrient solution restricted uptake and shoot translocation of Fe independently of N form and, therefore, induced Fe deficiency chlorosis at low Fe supply [1 micro M ferric ethylenediaminedi(O-hydroxyphenylacetic acid)]. Root NO(3)(-) supply (up to 40 mM) did not affect the relative distribution of Fe between leaf apoplast and symplast at constant low external pH of the root medium. Although perfusion of high pH-buffered solution (7.0) into the leaf apoplast restricted (59)Fe uptake rate as compared with low apoplastic solution pH (5.0 and 6.0, respectively), loading of NO(3)(-) (6 mM) showed no effect on (59)Fe uptake by the symplast of leaf cells. However, high light intensity strongly increased (59)Fe uptake, independently of apoplastic pH or of the presence of NO(3)(-) in the apoplastic solution. Finally, there are no indications in the present study that NO(3)(-) supply to roots results in the postulated inactivation of Fe in the leaf apoplast. It is concluded that NO(3)(-) nutrition results in Fe deficiency chlorosis exclusively by inhibited Fe acquisition by roots due to high pH at the root surface.

  9. Pore Water Pressure Contribution to Debris Flow Mobility

    Directory of Open Access Journals (Sweden)

    Chiara Deangeli

    2009-01-01

    Full Text Available Problem statement: Debris flows are very to extremely rapid flows of saturated granular soils. Two main types of debris flow are generally recognized: Open slope debris flows and channelized debris flows. The former is the results of some form of slope failures, the latter can develop along preexisting stream courses by the mobilization of previously deposited debris blanket. The problem to be addressed is the influence of the mode of initiation on the subsequent mechanism of propagation. In particular the role of pore water pressure on debris flow mobility in both types was debated. Approach: Laboratory flume experiments were set up in order to analyze the behavior of debris flows generated by model sand slope failures. Failures were induced in sand slopes by raising the water level by seepage from a drain located at the top end of the flume, and by rainfall supplied by a set of pierced plastic pipes placed above the flume. Video recordings of the tests were performed to analyze debris flow characteristics. Results: In all the tests the sand water mixture flows were unsteady and non uniform and sand deposition along the channel bed was a relevant phenomenon. The flows were characterized by a behavioral stratification of the sand water mixture along the flow depth. Back analyzed pore water pressure were just in excess to the hydrostatic condition. The reliability of the experimental results was checked by comparison with other flume experiment data. Conclusion: Debris flow behavior was influenced by the mode of initiation, the inclination of the channel and grain size of the soils. These factors affected the attained velocities and the pore water pressure values. The mobility of debris flows was not always enhanced by high excess pore water pressure values.

  10. The water value-flow concept

    NARCIS (Netherlands)

    Seyam, I.M.; Hoekstra, A.Y.; Savenije, H.H.G.

    2003-01-01

    The value of water is a key issue in managing water resources in an efficient, equitable and sustainable way. Efforts to assess the value of water are often not linked to the properties of the natural water system, which makes it difficult to analyse upstream–downstream dependency. In order to accou

  11. Self Calibrating Flow Estimation in Waste Water Pumping Stations

    DEFF Research Database (Denmark)

    Kallesøe, Carsten Skovmose; Knudsen, Torben

    2016-01-01

    Knowledge about where waste water is flowing in waste water networks is essential to optimize the operation of the network pumping stations. However, installation of flow sensors is expensive and requires regular maintenance. This paper proposes an alternative approach where the pumps and the waste...... water pit are used for estimating both the inflow and the pump flow of the pumping station. Due to the nature of waste water, the waste water pumps are heavily affected by wear and tear. To compensate for the wear of the pumps, the pump parameters, used for the flow estimation, are automatically...... calibrated. This calibration is done based on data batches stored at each pump cycle, hence makes the approach a self calibrating system. The approach is tested on a pumping station operating in a real waste water network....

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

    Science.gov (United States)

    : Belcher, Wayne R.

    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

  13. Trading water to improve environmental flow outcomes

    Science.gov (United States)

    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.

  14. Horizontal flow barriers for the transient ground-water flow model, Death Valley regional ground-water flow system, Nevada and California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This digital dataset defines the surface traces of regional features simulated as horizontal flow barriers in the Death Valley regional ground-water flow system...

  15. Accounting for environmental flow requirements in global water assessments

    NARCIS (Netherlands)

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

    2014-01-01

    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

  16. Globalisation of water resources: Global virtual water flows in relation to international crop trade

    NARCIS (Netherlands)

    Hoekstra, A.Y.; Hung, P.Q.

    2005-01-01

    The water that is used in the production process of a commodity is called the ‘virtual water’ contained in the commodity. International trade of commodities brings along international flows of virtual water. The objective of this paper is to quantify the volumes of virtual water flows between nation

  17. TWO-DIMENSIONAL PLANE WATER FLOW AND WATER QUALITY DISTRIBUTION IN BOSTEN LAKE

    Institute of Scientific and Technical Information of China (English)

    Feng Min-quan; Zhou Xiao-de; Zheng Bang-min; Min Tao; Zhao Ke-yu

    2003-01-01

    The two-dimensional plane water flow and water quality was developed by using the techniques of coordinate transformation, alternating directions, staggered grid, linear recurrence, and implicit scheme in the study of large water body in lakes. The model was proved to be suitable for treating the irregular boundary and predicting quickly water flow and water quality. The application of the model to the Bosten Lake in Xinjiang Uygur Autonomous Region of China shows that it is reasonable and practicable.

  18. Radar Based Flow and Water Level Forecasting in Sewer Systems

    DEFF Research Database (Denmark)

    Thorndahl, Søren; Rasmussen, Michael R.; Grum, M.

    2009-01-01

    This paper describes the first radar based forecast of flow and/or water level in sewer systems in Denmark. The rainfall is successfully forecasted with a lead time of 1-2 hours, and flow/levels are forecasted an additional ½-1½ hours using models describing the behaviour of the sewer system. Both...... radar data and flow/water level model are continuously updated using online rain gauges and online in-sewer measurements, in order to make the best possible predictions. The project show very promising results, and show large potentials, exploiting the existing water infrastructure in future climate...

  19. Regression modeling of ground-water flow

    Science.gov (United States)

    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)

  20. Silicon alleviates iron deficiency in cucumber by promoting mobilization of iron in the root apoplast

    DEFF Research Database (Denmark)

    Pavlovic, Jelena; Samardzic, Jelena; Maksimović, Vuk;

    2013-01-01

    Root responses to lack of iron (Fe) have mainly been studied in nutrient solution experiments devoid of silicon (Si). Here we investigated how Si ameliorates Fe deficiency in cucumber (Cucumis sativus) with focus on the storage and utilization of Fe in the root apoplast. A combined approach...... was performed including analyses of apoplastic Fe, reduction-based Fe acquisition and Fe-mobilizing compounds in roots along with the expression of related genes. Si-treated plants accumulated higher concentrations of root apoplastic Fe, which rapidly decreased when Fe was withheld from the nutrient solution....... Under Fe-deficient conditions, Si also increased the accumulation of Fe-mobilizing compounds in roots. Si supply stimulated root activity of Fe acquisition at the early stage of Fe deficiency stress through regulation of gene expression levels of proteins involved in Fe acquisition. However, when...

  1. An electrode polarization impedance based flow sensor for low water flow measurement

    Science.gov (United States)

    Yan, Tinghu; Sabic, Darko

    2013-06-01

    This note describes an electrode polarization impedance based flow sensor for low water flow measurement. It consists of two pairs of stainless steel electrodes set apart and inserted into a non-conductive flow tube with each pair of electrodes placed diametrically at the opposite sides. The flow sensor is modeled as a typical four-electrode system of which two electrodes are current-carrying and the other two serve as output pick ups. The polarization impedances of the two current carrying electrodes are affected by water flows resulting in changes of differential potential between the two pick-up electrodes which are separated by the same fluid. The interrogation of the two excitation electrodes with dc biased ac signals offers significantly higher sensor sensitivities to flow. The prototype flow sensor constructed for a 20 mm diameter pipeline was able to measure water flow rate as low as tested at 1.06 l h-1 and remained sensitive at a flow rate of 25.18 l h-1 when it was driven with a sinusoidal voltage at 1000 Hz with a peak ac amplitude of 2 V and a dc offset of +8 V. The nonlinear characteristics of the sensor response indicate that the sensor is more sensitive at low flows and will not be able to measure at very high flows. Additional experiments are needed to evaluate the influences of impurities, chemical species, ions constituents, conductivity and temperature over a practical range of residential water conditions, the effects of fluctuating ground signals, measurement uncertainty, power consumption, compensation of effects and practical operations. The flow sensor (principle) presented may be used as (in) a secondary sensor in combination with an existing electronic water meter to extend the low end of measurement range in residential water metering.

  2. Initial Survey Instructions for Spring Water Monitoring : Flow

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Initial survey instructions for the Spring Water Monitoring - Flow 1.02 survey at Fish Springs National Wildlife Refuge. This coop baseline monitoring survey has...

  3. Periodic equatorial water flows from a Hamiltonian perspective

    Science.gov (United States)

    Ionescu-Kruse, Delia; Martin, Calin Iulian

    2017-04-01

    The main result of this paper is a Hamiltonian formulation of the nonlinear governing equations for geophysical periodic stratified water flows in the equatorial f-plane approximation allowing for piecewise constant vorticity.

  4. Governing urban water flows in China

    NARCIS (Netherlands)

    Zhong, L.

    2007-01-01

    China has been witnessing an unprecedented period of continuous high economic growth during the past three decades. But this has been paralleled by severe environmental challenges, of which water problems are of key importance. This thesis addresses the urban water challenges of contemporary China,

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

    Science.gov (United States)

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

    2016-01-01

    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.

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

    Science.gov (United States)

    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. \

  7. Flow improvers for water injection based on surfactants

    Energy Technology Data Exchange (ETDEWEB)

    Oskarsson, H.; Uneback, I.; Hellsten, M.

    2006-03-15

    In many cases it is desirable to increase the flow of injection water when an oil well deteriorates. It is very costly in offshore operation to lay down an additional water pipe to the injection site. Flow improvers for the injection water will thus be the most cost-effective way to increase the flow rate. During the last years water-soluble polymers have also been applied for this purpose. These drag-reducing polymers are however only slowly biodegraded which has been an incentive for the development of readily biodegradable surfactants as flow improvers for injection water. A combination of a zwitterionic and an anionic surfactant has been tested in a 5.5 inch, 700 m long flow loop containing sulphate brine with salinity similar to sea water. A drag reduction between 75 and 80% was achieved with 119 ppm in solution of the surfactant blend at an average velocity of 1.9 m/s and between 50 and 55% at 2.9 m/s. The surfactants in this formulation were also found to be readily biodegradable in sea water and low bio accumulating which means they have an improved environmental profile compared to the polymers used today. Due to the self-healing properties of the drag-reducing structures formed by surfactants, these may be added before the pump section - contrary to polymers which are permanently destroyed by high shear forces. (Author)

  8. Potential structural barriers to ground-water flow, Death Valley regional ground-water flow system, Nevada and California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This digital dataset defines the surface traces of regional geologic structures designated as potential ground-water flow barriers in an approximately 45,000...

  9. An Experimental Study of Oil / Water Flow in Horizontal Pipes

    Energy Technology Data Exchange (ETDEWEB)

    Elseth, Geir

    2001-07-01

    The purpose of this thesis is to study the behaviour of the simultaneous flow of oil and water in horizontal pipes. In this connection, two test facilities are used. Both facilities have horizontal test sections with inner pipe diameters equal to 2 inches. The largest facility, called the model oil facility, has reservoirs of 1 m{sub 3} of each medium enabling flow rates as high as 30 m{sub 3}/h, which corresponds to mixture velocities as high as 3.35 m/s. The flow rates of oil and water can be varied individually producing different flow patterns according to variations in mixture velocity and input water cut. Two main classes of flows are seen, stratified and dispersed. In this facility, the main focus has been on stratified flows. Pressure drops and local phase fractions are measured for a large number of flow conditions. Among the instruments used are differential pressure transmitters and a traversing gamma densitometer, respectively. The flow patterns that appear are classified in flow pattern maps as functions of either mixture velocity and water cut or superficial velocities. From these experiments a smaller number of stratified flows are selected for studies of velocity and turbulence. A laser Doppler anemometer (LDA) is applied for these measurements in a transparent part of the test section. To be able to produce accurate measurements a partial refractive index matching procedure is used. The other facility, called the matched refractive index facility, has a 0.2 m{sub 3} reservoir enabling mainly dispersed flows. Mixture velocities range from 0.75 m/s to 3 m/s. The fluids in this facility are carefully selected to match the refractive index of the transparent part of the test section. A full refractive index matching procedure is carried out producing excellent optical conditions for velocity and turbulence studies by LDA. In addition, pressure drops and local phase fractions are measured. (author)

  10. The role of hand calculations in ground water flow modeling.

    Science.gov (United States)

    Haitjema, Henk

    2006-01-01

    Most ground water modeling courses focus on the use of computer models and pay little or no attention to traditional analytic solutions to ground water flow problems. This shift in education seems logical. Why waste time to learn about the method of images, or why study analytic solutions to one-dimensional or radial flow problems? Computer models solve much more realistic problems and offer sophisticated graphical output, such as contour plots of potentiometric levels and ground water path lines. However, analytic solutions to elementary ground water flow problems do have something to offer over computer models: insight. For instance, an analytic one-dimensional or radial flow solution, in terms of a mathematical expression, may reveal which parameters affect the success of calibrating a computer model and what to expect when changing parameter values. Similarly, solutions for periodic forcing of one-dimensional or radial flow systems have resulted in a simple decision criterion to assess whether or not transient flow modeling is needed. Basic water balance calculations may offer a useful check on computer-generated capture zones for wellhead protection or aquifer remediation. An easily calculated "characteristic leakage length" provides critical insight into surface water and ground water interactions and flow in multi-aquifer systems. The list goes on. Familiarity with elementary analytic solutions and the capability of performing some simple hand calculations can promote appropriate (computer) modeling techniques, avoids unnecessary complexity, improves reliability, and is likely to save time and money. Training in basic hand calculations should be an important part of the curriculum of ground water modeling courses.

  11. Soil Moisture Data Assimilation in Soil Water Flow Modeling

    Science.gov (United States)

    Pachepsky, Y. A.; Guber, A.; Jacques, D.; Pan, F.; van Genuchten, M.; Cady, R. E.; Nicholson, T. J.

    2010-12-01

    Soil water flow modeling has multiple applications. This modeling is based on simplifications stemming from both conceptual uncertainty and lack of detailed knowledge about parameters. Modern soil moisture sensors can provide detailed information about changes in soil water content in time and with depth. This information can be used for data assimilation in soil water flow modeling. The ensemble Kalman filter appears to be an appropriate method for that. Earlier we demonstrated ensemble simulations of soil water flow by using sets of pedotransfer functions (empirical relationships between soil hydraulic properties and soil basic properties, such as particle size distribution, bulk density, organic carbon content, etc.). The objective of this work was to apply the data assimilation with the ensemble Kalman filter to soil water flow modeling, using soil water content monitoring with TDR probes and an ensemble of soil water flow models parameterized with different pedotransfer functions. Experiments were carried out at the Bekkevoort site, Belgium. Sixty time domain reflectometry (TDR) probes with two rods) were installed along the trench in loamy soil at 12 locations with 50-cm horizontal spacing at five depths (15, 35, 55, 75, and 95 cm). Water content and weather parameters were monitored for one year with 15 min frequency. Soil water flow was simulated using the HYDRUS6 software. Mean daily means of water contents at the observation depths were the measurements used in data assimilation. Eighteen pedotransfer functions for water retention and one for hydraulic conductivity were applied to generate ensembles to evaluate the uncertainty in simulation results, whereas the replicated measurements at each of measurement depths were used to characterize the uncertainty in data. Data assimilation appeared to be very efficient. Even assimilating measurements at a single depth provided substantial improvement in simulations at other observation depths. Results on

  12. Computing nonhydrostatic shallow-water flow over steep terrain

    Science.gov (United States)

    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.

  13. Launch Environment Water Flow Simulations Using Smoothed Particle Hydrodynamics

    Science.gov (United States)

    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.

  14. Accounting for environmental flow requirements in global water assessments

    NARCIS (Netherlands)

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

    2013-01-01

    With growing water needs for food production, it is necessary to improve the quantification of "Environmental Flow Requirements (EFRs)" to secure enough water for the freshwater ecosystems. In this study, five methods for calculating EFRs were compared to 11 case studies of locally-calculated EFRs.

  15. TRENDS IN VARIABILITY OF WATER FLOW OF TELEAJEN RIVER

    Directory of Open Access Journals (Sweden)

    N. JIPA

    2012-03-01

    Full Text Available TRENDS IN VARIABILITY OF WATER FLOW OF TELEAJEN RIVER. In the context of climate change at global and regional scale, this study intends to identify the trends in variability of the annual and monthly flow of Teleajen river. The study is based on processing the series of mean, maximum and minimum flows at Cheia and Moara Domnească hydrometric stations (these data were taken from the National Institute of Meteorology and Hydrology. The period of analysis is 1966-1998, statistical methods beeing mostly used, among which the Mann – Kendall test, that identifies the liniar trend and its statistic significance, comes into focus. The trends in the variability of water annual and monthly flows are highlighted. The results obtained show downward trends for the mean and maximum annual flows, and for the minimum water discharge, a downward trend for Cheia station and an upward trend for Moara Domnească station. Knowing the trends in the variability of the rivers’ flow is important empirically in view of taking adequate administration measures of the water resources and managment measures for the risks lead by extreme hidrologic events (floods, low-water, according to the possible identified changes.

  16. WEAKLY SWIRLING TURBULENT FLOW IN TURBID WATER HYDRAULIC SEPARATION DEVICE

    Institute of Scientific and Technical Information of China (English)

    LI Lin; QIU Xiu-yun; JIN Sheng; XIAO Jun; GONG Shou-yuan

    2008-01-01

    This article deals with the characteristics of weakly swirling turbulent flow field in a Turbid Water Hydraulic Separation Device (TWHSD) through experimental and numerical researches. The flow field was measured by PIV, which provided streamlines, vortex structure, vorticity and velocity distribution in different test planes in the TWHSD. On the basis of the experimental results, the tangential and radial velocity distributions of the swirling flow field were obtained. Meanwhile, the numerical simulations were conducted with the RNG and RSM turbulence models, respectively. According to the experimental and numerical results, the characteristics of the clear water flow field inside the TWHSD were determined. In view of simulation accuracy and time consumption, it is suggested to apply the RNG model instead of the RSM model, which is more time consuming, to make further study on two-phases flow fields in the device.

  17. Continuum simulations of water flow past fullerene molecules

    Science.gov (United States)

    Popadić, A.; Praprotnik, M.; Koumoutsakos, P.; Walther, J. H.

    2015-09-01

    We present continuum simulations of water flow past fullerene molecules. The governing Navier-Stokes equations are complemented with the Navier slip boundary condition with a slip length that is extracted from related molecular dynamics simulations. We find that several quantities of interest as computed by the present model are in good agreement with results from atomistic and atomistic-continuum simulations at a fraction of the cost. We simulate the flow past a single fullerene and an array of fullerenes and demonstrate that such nanoscale flows can be computed efficiently by continuum flow solvers, allowing for investigations into spatiotemporal scales inaccessible to atomistic simulations.

  18. Multiscale simulation of water flow past a C540 fullerene

    Science.gov (United States)

    Walther, Jens H.; Praprotnik, Matej; Kotsalis, Evangelos M.; Koumoutsakos, Petros

    2012-04-01

    We present a novel, three-dimensional, multiscale algorithm for simulations of water flow past a fullerene. We employ the Schwarz alternating overlapping domain method to couple molecular dynamics (MD) of liquid water around the C540 buckyball with a Lattice-Boltzmann (LB) description for the Navier-Stokes equations. The proposed method links the MD and LB domains using a fully three-dimensional interface and coupling of velocity gradients. The present overlapping domain method implicitly preserves the flux of mass and momentum and bridges flux-based and Schwarz domain decomposition algorithms. We use this method to determine the slip length and hydrodynamic radius for water flow past a buckyball.

  19. A design methodology for cross flow water turbines

    Energy Technology Data Exchange (ETDEWEB)

    Zanette, J.; Imbault, D.; Tourabi, A. [Laboratoire Sols, Solides, Structures - Risques (3S-R) Domaine Universitaire, B.P. 53, 38041 Grenoble Cedex 9 (France)

    2010-05-15

    This contribution deals with the design of cross flow water turbines. The mechanical stress sustained by the blades depends on the basic geometrical specifications of the cross flow water turbine, its rotational speed, the exact geometry of the blades and the velocity of the upstream water current. During the operation, the blades are submitted to severe cyclic loadings generated by pressure field's variation as function of angular position. This paper proposes a simplified design methodology for structural analysis of cross flow water turbine blades, with quite low computational time. A new trapezoidal-bladed turbine obtained from this method promises to be more efficient than the classical designs. Its most distinctive characteristic is a variable profiled cross-section area, which should significantly reduce the intensity of cyclic loadings in the material and improve the turbine's durability. The advantages of this new geometry will be compared with three other geometries based on NACA0018 hydrofoil. (author)

  20. Autohydrolysis of plant xylans by apoplastic expression of thermophilic bacterial endo-xylanases

    DEFF Research Database (Denmark)

    Borkhardt, Bernhard; Harholt, Jesper; Ulvskov, Peter Bjarne

    2010-01-01

    The genes encoding the two endo-xylanases XynA and XynB from the thermophilic bacterium Dictyoglomus thermophilum were codon optimized for expression in plants. Both xylanases were designed to be constitutively expressed under the control of the CaMV 35S promoter and targeted to the apoplast. Tra...

  1. Apoplastic and intracellular plant sugars regulate developmental transitions in witches’ broom disease of cacao

    Science.gov (United States)

    Barau, Joan; Grandis, Adriana; Carvalho, Vinicius Miessler de Andrade; Teixeira, Gleidson Silva; Zaparoli, Gustavo Henrique Alcalá; do Rio, Maria Carolina Scatolin; Rincones, Johana; Buckeridge, Marcos Silveira; Pereira, Gonçalo Amarante Guimarães

    2015-01-01

    Witches’ broom disease (WBD) of cacao differs from other typical hemibiotrophic plant diseases by its unusually long biotrophic phase. Plant carbon sources have been proposed to regulate WBD developmental transitions; however, nothing is known about their availability at the plant–fungus interface, the apoplastic fluid of cacao. Data are provided supporting a role for the dynamics of soluble carbon in the apoplastic fluid in prompting the end of the biotrophic phase of infection. Carbon depletion and the consequent fungal sensing of starvation were identified as key signalling factors at the apoplast. MpNEP2, a fungal effector of host necrosis, was found to be up-regulated in an autophagic-like response to carbon starvation in vitro. In addition, the in vivo artificial manipulation of carbon availability in the apoplastic fluid considerably modulated both its expression and plant necrosis rate. Strikingly, infected cacao tissues accumulated intracellular hexoses, and showed stunted photosynthesis and the up-regulation of senescence markers immediately prior to the transition to the necrotrophic phase. These opposite findings of carbon depletion and accumulation in different host cell compartments are discussed within the frame of WBD development. A model is suggested to explain phase transition as a synergic outcome of fungal-related factors released upon sensing of extracellular carbon starvation, and an early senescence of infected tissues probably triggered by intracellular sugar accumulation. PMID:25540440

  2. Apoplastic and intracellular plant sugars regulate developmental transitions in witches' broom disease of cacao.

    Science.gov (United States)

    Barau, Joan; Grandis, Adriana; Carvalho, Vinicius Miessler de Andrade; Teixeira, Gleidson Silva; Zaparoli, Gustavo Henrique Alcalá; do Rio, Maria Carolina Scatolin; Rincones, Johana; Buckeridge, Marcos Silveira; Pereira, Gonçalo Amarante Guimarães

    2015-03-01

    Witches' broom disease (WBD) of cacao differs from other typical hemibiotrophic plant diseases by its unusually long biotrophic phase. Plant carbon sources have been proposed to regulate WBD developmental transitions; however, nothing is known about their availability at the plant-fungus interface, the apoplastic fluid of cacao. Data are provided supporting a role for the dynamics of soluble carbon in the apoplastic fluid in prompting the end of the biotrophic phase of infection. Carbon depletion and the consequent fungal sensing of starvation were identified as key signalling factors at the apoplast. MpNEP2, a fungal effector of host necrosis, was found to be up-regulated in an autophagic-like response to carbon starvation in vitro. In addition, the in vivo artificial manipulation of carbon availability in the apoplastic fluid considerably modulated both its expression and plant necrosis rate. Strikingly, infected cacao tissues accumulated intracellular hexoses, and showed stunted photosynthesis and the up-regulation of senescence markers immediately prior to the transition to the necrotrophic phase. These opposite findings of carbon depletion and accumulation in different host cell compartments are discussed within the frame of WBD development. A model is suggested to explain phase transition as a synergic outcome of fungal-related factors released upon sensing of extracellular carbon starvation, and an early senescence of infected tissues probably triggered by intracellular sugar accumulation.

  3. The dynamics of apoplast phenolics in tobacco leaves following inoculation with bacteria

    Directory of Open Access Journals (Sweden)

    Con Jacyn Baker

    2015-08-01

    Full Text Available This study demonstrates that the accumulation of apoplastic phenolics is stimulated in planta in response to bacterial inoculation. Past studies have shown that levels of extracellular phenolics are elicited in plant cell suspensions in response to bacteria, and that tomato plants infected with viroids showed changes in apoplastic phenolics. The method described here monitored changes in apoplastic phenolics in tobacco leaves following bacterial inoculation of the same tissue. Inoculation with a saprophyte, Pseudomonas fluorescens, which does not cause visible symptoms or physical damage, was used to elicit phenolics and examine the effects of variable parameters on phenolic composition. Location of the inoculation on the leaf, position or developmental age of the leaf on the plant, and inoculum concentration were standardized for further experiments. The patterns of phenolic change in the apoplast were compared for tobacco inoculated with P. syringae pathovars, pv. syringae, which causes a resistant HR reaction within 15 h, and pv. tabaci, which causes a susceptible reaction with delayed visible symptoms. Both pathogens elicited lower increased levels of acetosyringone compared to the saprophyte, P. fluorescens but had greatly increased levels of the chlorogenic acid derivatives. The latter metabolites appear to have come from the intracellular stores, which could

  4. Plant fluid proteomics: Delving into the xylem sap, phloem sap and apoplastic fluid proteomes

    Science.gov (United States)

    The phloem sap, xylem sap and apoplastic fluid play key roles in long and short distance transport of signals and nutrients, and act as a barrier against local and systemic pathogen infection. Among other components, these plant fluids contain proteins which are likely to be important players in the...

  5. Apoplastic polyesters in Arabidopsis surface tissues--a typical suberin and a particular cutin.

    Science.gov (United States)

    Franke, Rochus; Briesen, Isabel; Wojciechowski, Tobias; Faust, Andrea; Yephremov, Alexander; Nawrath, Christiane; Schreiber, Lukas

    2005-11-01

    Cutinized and suberized cell walls form physiological important plant-environment interfaces as they act as barriers limiting water and nutrient loss and protect from radiation and invasion by pathogens. Due to the lack of protocols for the isolation and analysis of cutin and suberin in Arabidopsis, the model plant for molecular biology, mutants and transgenic plants with a defined altered cutin or suberin composition are unavailable, causing that structure and function of these apoplastic barriers are still poorly understood. Transmission electron microscopy (TEM) revealed that Arabidopsis leaf cuticle thickness ranges from only 22 nm in leaf blades to 45 nm on petioles, causing the difficulty in cuticular membrane isolation. We report the use of polysaccharide hydrolases to isolate Arabidopsis cuticular membranes, suitable for depolymerization and subsequent compositional analysis. Although cutin characteristic omega-hydroxy acids (7%) and mid-chain hydroxylated fatty acids (8%) were detected, the discovery of alpha,omega-diacids (40%) and 2-hydroxy acids (14%) as major depolymerization products reveals a so far novel monomer composition in Arabidopsis cutin, but with chemical analogy to root suberin. Histochemical and TEM analysis revealed that suberin depositions were localized to the cell walls in the endodermis of primary roots and the periderm of mature roots of Arabidopsis. Enzyme digested and solvent extracted root cell walls when subjected to suberin depolymerization conditions released omega-hydroxy acids (43%) and alpha,omega-diacids (24%) as major components together with carboxylic acids (9%), alcohols (6%) and 2-hydroxyacids (0.1%). This similarity to suberin of other species indicates that Arabidopsis roots can serve as a model for suberized tissue in general.

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

    OpenAIRE

    2016-01-01

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

  7. Nitrogen transformations in wetlands: Effects of water flow patterns

    Energy Technology Data Exchange (ETDEWEB)

    Davidsson, T.

    1997-11-01

    In this thesis, I have studied nitrogen turnover processes in water meadows. A water meadow is a wetland where water infiltrates through the soil of a grassland field. It is hypothesized that infiltration of water through the soil matrix promotes nutrient transformations compared to surface flow of water, by increasing the contact between water, nutrients, soil organic matter and bacteria. I have studied how the balance between nitrogen removal (denitrification, assimilative uptake, adsorption) and release (mineralization, desorption) processes are affected by water flow characteristics. Mass balance studies and direct denitrification measurements at two field sites showed that, although denitrification was high, net nitrogen removal in the water meadows was poor. This was due to release of ammonium and dissolved organic nitrogen (DON) from the soils. In laboratory studies, using {sup 15}N isotope techniques, I have shown that nitrogen turnover is considerably affected by hydrological conditions and by soil type. Infiltration increased virtually all the nitrogen processes, due to deeper penetration of nitrate and oxygen, and extended zones of turnover processes. On the contrary, soils and sediments with surface water flow, diffusion is the main transfer mechanism. The relation between release and removal processes sometimes resulted in shifts towards net nitrogen production. This occurred in infiltration treatments when ammonium efflux was high in relation to denitrification. It was concluded that ammonium and DON was of soil origin and hence not a product of dissimilatory nitrate reduction to ammonium. Both denitrification potential and mineralization rates were higher in peaty than in sandy soil. Vertical or horizontal subsurface flow is substantial in many wetland types, such as riparian zones, tidal salt marshes, fens, root-zone systems and water meadows. Moreover, any environment where aquatic and terrestrial ecosystems meet, and where water level fluctuates

  8. Ammonium improves iron nutrition by decreasing leaf apoplastic pH of sunflower plants (Helianthus annuus L. cv. Frankasol)

    Institute of Scientific and Technical Information of China (English)

    ZOU Chunqin; ZHANG Fusuo

    2003-01-01

    The effect of nitrogen form on pH and concentration of soluble iron (Fe) in leaf apoplast was investigated in hydrophonically grown sunflower plants (Helianthus annuus L. cv. Frankasol), and the mechanism underlying the improved Fe nutrition by ammonium (NH4) supply was also elucidated. Ammonium supply ameliorated Fe nutrition of plants grown without Fe through decreasing apoplastic pH and increasing soluble Fe concentration in apoplastic fluid of young leaves. The soluble Fe concentration in apoplastic fluid and cell sap of young leaves, and xylem exudates of NH4 fed-plants was higher than that of nitrate (NO3) fed-plants, and no typical Fe-deficiency chlorosis in young leaves was observed in NH4 fed plant without Fe supply. The apoplastic pH was 6.15 and 5.94 in young leaves of Fe-deficient plants fed respectively with NO3 and NH4, while in Fe-sufficient plants, the apoplastic pH was 6.43 with NO3, and 5.50 with NH4 supply. In primary leaves, the apoplastic pH was around 6.25 irrespective of nitrogen form and Fe supply. The pH of xylem exudate was 5.72 in Fe-deficient plants fed with NO3 and 5.49 with NH4. Iron nutrition increased the pH of xylem exudate by 0.27 and 0.16 unit under NO3 and NH4 supply respectively.

  9. Experimental study of flow patterns and pressure drops of heavy oil-water-gas vertical flow

    Institute of Scientific and Technical Information of China (English)

    LIU Xi-mao; ZHONG Hai-quan; LI Ying-chuan; LIU Zhong-neng; WANG Qi

    2014-01-01

    A stainless steel apparatus of 18.5 m high and 0.05 m in inner diameter is developed, with the heavy oil from Lukeqin Xinjiang oil field as the test medium, to carry out the orthogonal experiments for the interactions between heavy oil-water and heavy oil-water-gas. With the aid of observation windows, the pressure drop signal can be collected and the general multiple flow patterns of heavy oil-water-gas can be observed, including the bubble, slug, churn and annular ones. Compared with the conventional oil, the bubble flows are identified in three specific flow patterns which are the dispersed bubble (DB), the bubble gas-bubble heavy oil go(B-B), and the bubble gas-intermittent heavy oilgo(B-I). The slug flows are identified in two specific flow patterns which are the intermittent gas-bubble heavy oilgo(I-B)and the intermittent gas-intermittent heavy oilgo(I-I). Compared with the observa- tions in the heavy oil-water experiment, it is found that the conventional models can not accurately predict the pressure gradient. And it is not water but heavy oil and water mixed phase that is in contact with the tube wall. So, based on the principle of the energy con- servation and the kinematic wave theory, a new method is proposed to calculate the frictional pressure gradient. Furthermore, with the new friction gradient calculation method and a due consideration of the flow characteristics of the heavy oil-water-gas high speed flow, a new model is built to predict the heavy oil-water-gas pressure gradient. The predictions are compared with the experiment data and the field data. The accuracy of the predictions shows the rationality and the applicability of the new model.

  10. Extended Approach to Water Flow Algorithm for Text Line Segmentation

    Institute of Scientific and Technical Information of China (English)

    Darko Brodi(c)

    2012-01-01

    This paper proposes a new approach to the water flow algorithm for text line segmentation.In the basic method the hypothetical water flows under few specified angles which have been defined by water flow angle as parameter.It is applied to the document image frame from left to right and vice versa.As a result,the unwetted and wetted areas are established.Thesc areas separate text from non-text elements in each text line,respectively.Hence,they represent the control areas that are of major importance for text line segmentation.Primarily,an extended approach means extraction of the connected-components by bounding boxes ovcr text.By this way,each connected component is mutually separated.Hence,the water flow angle,which defines the unwetted areas,is determined adaptively.By choosing appropriate water flow angle,the unwetted areas are lengthening which leads to the better text line segmentation.Results of this approach are encouraging due to the text line segmentation improvement which is the most challenging step in document image processing.

  11. Boundary of the area contributing flow to the Death Valley regional ground-water flow system, Nevada and California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This digital data set defines the boundary of the area contributing ground-water flow to the Death Valley regional ground-water flow-system (DVRFS) model domain. The...

  12. Boundary of the area contributing flow to the Death Valley regional ground-water flow system, Nevada and California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This digital data set defines the boundary of the area contributing ground-water flow to the Death Valley regional ground-water flow-system (DVRFS) model domain....

  13. Water flow experiments and analyses on the cross-flow type mercury target model with the flow guide plates

    CERN Document Server

    Haga, K; Kaminaga, M; Hino, R

    2001-01-01

    A mercury target is used in the spallation neutron source driven by a high-intensity proton accelerator. In this study, the effectiveness of the cross-flow type mercury target structure was evaluated experimentally and analytically. Prior to the experiment, the mercury flow field and the temperature distribution in the target container were analyzed assuming a proton beam energy and power of 1.5 GeV and 5 MW, respectively, and the feasibility of the cross-flow type target was evaluated. Then the average water flow velocity field in the target mock-up model, which was fabricated from Plexiglass for a water experiment, was measured at room temperature using the PIV technique. Water flow analyses were conducted and the analytical results were compared with the experimental results. The experimental results showed that the cross-flow could be realized in most of the proton beam path area and the analytical result of the water flow velocity field showed good correspondence to the experimental results in the case w...

  14. Stability of steam-water countercurrent stratified flow

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S C

    1985-10-01

    Two flow instabilities which limit the normal condensation processes in countercurrent stratified steam-water flow have been identified experimentally: flooding and condensation-induced waterhammer. In order to initiate condensation-induced waterhammer in nearly horizontal or moderately-inclined steam/subcooled-water flow, two conditions, the appearance of a wavy interface and complete condensation of the incoming steam, are necessary. Analyses of these conditions are performed on a basis of flow stability and heat transfer considerations. Flooding data for several inclinations and channel heights are collected. Effects of condensation, inclination angle and channel height on the flooding characteristics are discussed. An envelope theory for the onset of flooding in inclined stratified flow is developed, which agrees well with the experimental data. Some empirical information on basic flow parameters, such as mean film thickness and interfacial friction factor required for this theory are measured. The previous viewpoints on flooding appear not to conflict with the present experimental data in nearly horizontal flow but the flooding phenomena in nearly vertical flow appear to be more complicated than those described by these viewpoints because of liquid droplet entrainment.

  15. Unstable Pore-Water Flow in Intertidal Wetlands

    Science.gov (United States)

    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

  16. How fast does water flow in carbon nanotubes?

    DEFF Research Database (Denmark)

    Kannam, Sridhar; Todd, Billy; Hansen, Jesper Schmidt

    2013-01-01

    the slip length using equilibrium molecular dynamics (EMD) simulations, from which the interfacial friction between water and carbon nanotubes can be found, and also via external field driven non-equilibrium molecular dynamics simulations (NEMD). We discuss some of the issues in simulation studies which......The purpose of this paper is threefold. First, we review the existing literature on flow rates of water in carbon nanotubes. Data for the slip length which characterizes the flow rate are scattered over 5 orders of magnitude for nanotubes of diameter 0.81–10 nm. Second, we precisely compute...... and reliably extrapolate the results for the slip length to values of the field corresponding to experimentally accessible pressure gradients. Finally, we comment on several issues concerning water flow rates in carbon nanotubes which may lead to some future research directions in this area....

  17. Analysis on Issues of Variable Flow Water System

    Directory of Open Access Journals (Sweden)

    Jinming Yang

    2013-09-01

    Full Text Available Variable flow water system has played an important role in the field of energy saving with the Electronic Variable Frequency Drive (VFD widely used in practical projects. How to control the frequency converter to work properly is an essential issue which we must first emphatically solve. The control technology of frequency converter is closely related to characteristics of pumps. Based on the mathmatical a model of pumps with or without inverters, the article discusses some issues in detail, such as inverters configuration, flow rate regulation and overload. These are key issues of control technology of variable flow water system. For those multiple-pump water systems, the engineers may select synchronous frequency conversion control technology or Add-Sub pumps control technology to achieve the maximum energy-saving benefits.  

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

    Science.gov (United States)

    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…

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

    NARCIS (Netherlands)

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

    2012-01-01

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

  20. Sap flow index as an indicator of water storage use

    Directory of Open Access Journals (Sweden)

    Nadezhdina Nadezhda

    2015-06-01

    Full Text Available Symmetrical temperature difference also known as the sap flow index (SFI forms the basis of the Heat Field Deformation sap flow measurement and is simultaneously collected whilst measuring the sap flow. SFI can also be measured by any sap flow method applying internal continuous heating through the additional installation of an axial differential thermocouple equidistantly around a heater. In earlier research on apple trees SFI was found to be an informative parameter for tree physiological studies, namely for assessing the contribution of stem water storage to daily transpiration. The studies presented in this work are based on the comparative monitoring of SFI and diameter in stems of different species (Pseudotsuga menziesii, Picea omorika, Pinus sylvestris and tree sizes. The ability of SFI to follow the patterns of daily stem water storage use was empirically confirmed by our data. Additionally, as the HFD multipointsensors can measure sap flow at several stem sapwood depths, their use allowed to analyze the use of stored water in different xylem layers through SFI records. Radial and circumferential monitoring of SFI on large cork oak trees provided insight into the relative magnitude and timing of the contribution of water stored in different sapwood layers or stem sectors to transpiration.

  1. Experimental investigation on flow characteristics of deionized water in microtubes

    Institute of Scientific and Technical Information of China (English)

    XU ShaoLiang; YUE XiangAn; HOU JiRui

    2007-01-01

    The flow characteristics of deionized water in microtubes with diameters ranging from 2 to 30 μm are investigated. The experimental results show that the flow characteristics in microtubes with diameters of 16 μm and larger ones are in agreement with the classical theory. However, as the diameters are decreased to 5 and 2 μm, the nonlinear flow characteristics prevail and the results indicate significant departure of flow characteristics from the predictions of the conventional theory, and the smaller the diameters, the larger the departure. As the Reynolds number increases, the degree of nonlinear flow characteristics decrease gradually and the experimental results are approximately equal to the theoretical expectation. The minimum Reynolds number in this study is only 2.46×10-5.

  2. DIGITAL IMAGE MEASUREMENT OF BUBBLE MOTION IN AERATED WATER FLOWS

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Digital image measurement method, as an ex-tension of Particle Image Velocimetry of single-phase flowmeasurement, was investigated for application to air-watertwo-phase flows. The method has strong potential ability inmeasuring bubble geometrical features and moving velocitiesfor complex bubble motion in aerated water flow. Both dilutedand dense bubble rising flows are measured using the digitalimage method. Measured bubble shapes and sizes, and bubblevelocities are affected by threshold selection for binary image.Several algorithms for selecting threshold are compared andmethods for calculating the time-averaged void fraction arediscussed.

  3. Ground water recharge and flow characterization using multiple isotopes.

    Science.gov (United States)

    Chowdhury, Ali H; Uliana, Matthew; Wade, Shirley

    2008-01-01

    Stable isotopes of delta(18)O, delta(2)H, and (13)C, radiogenic isotopes of (14)C and (3)H, and ground water chemical compositions were used to distinguish ground water, recharge areas, and possible recharge processes in an arid zone, fault-bounded alluvial aquifer. Recharge mainly occurs through exposed stream channel beds as opposed to subsurface inflow along mountain fronts. This recharge distribution pattern may also occur in other fault-bounded aquifers, with important implications for conceptualization of ground water flow systems, development of ground water models, and ground water resource management. Ground water along the mountain front near the basin margins contains low delta(18)O, (14)C (percent modern carbon [pmC]), and (3)H (tritium units [TU]), suggesting older recharge. In addition, water levels lie at greater depths, and basin-bounding faults that locally act as a flow barrier may further reduce subsurface inflow into the aquifer along the mountain front. Chemical differences in ground water composition, attributed to varying aquifer mineralogy and recharge processes, further discriminate the basin-margin and the basin-center water. Direct recharge through the indurated sandstones and mudstones in the basin center is minimal. Modern recharge in the aquifer is mainly through the broad, exposed stream channel beds containing coarse sand and gravel where ground water contains higher delta(18)O, (14)C (pmC), and (3)H (TU). Spatial differences in delta(18)O, (14)C (pmC), and (3)H (TU) and occurrences of extensive mudstones in the basin center suggest sluggish ground water movement, including local compartmentalization of the flow system.

  4. Boundary of the ground-water flow model by IT Corporation (1996), for the Death Valley regional ground-water flow system study, Nevada and California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This digital data set defines the boundary of the steady-state ground-water flow model built by IT Corporation (1996). The regional, 20-layer ground-water flow...

  5. Material-property zones used in the transient ground-water flow model of the Death Valley regional ground-water flow system, Nevada and California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Zones in this data set represent spatially contiguous areas that influence ground-water flow in the Death Valley regional ground-water flow system (DVRFS), an...

  6. Control algorithm for multiscale flow simulations of water

    DEFF Research Database (Denmark)

    Kotsalis, E. M.; Walther, Jens Honore; Kaxiras, E.

    2009-01-01

    . The use of a mass conserving specular wall results in turn to spurious oscillations in the density profile of the atomistic description of water. These oscillations can be eliminated by using an external boundary force that effectively accounts for the virial component of the pressure. In this Rapid......We present a multiscale algorithm to couple atomistic water models with continuum incompressible flow simulations via a Schwarz domain decomposition approach. The coupling introduces an inhomogeneity in the description of the atomistic domain and prevents the use of periodic boundary conditions...... Communication, we extend a control algorithm, previously introduced for monatomic molecules, to the case of atomistic water and demonstrate the effectiveness of this approach. The proposed computational method is validated for the cases of equilibrium and Couette flow of water....

  7. Control algorithm for multiscale flow simulations of water

    Science.gov (United States)

    Kotsalis, Evangelos M.; Walther, Jens H.; Kaxiras, Efthimios; Koumoutsakos, Petros

    2009-04-01

    We present a multiscale algorithm to couple atomistic water models with continuum incompressible flow simulations via a Schwarz domain decomposition approach. The coupling introduces an inhomogeneity in the description of the atomistic domain and prevents the use of periodic boundary conditions. The use of a mass conserving specular wall results in turn to spurious oscillations in the density profile of the atomistic description of water. These oscillations can be eliminated by using an external boundary force that effectively accounts for the virial component of the pressure. In this Rapid Communication, we extend a control algorithm, previously introduced for monatomic molecules, to the case of atomistic water and demonstrate the effectiveness of this approach. The proposed computational method is validated for the cases of equilibrium and Couette flow of water.

  8. Virtual water trade flows and savings under climate change

    Science.gov (United States)

    Konar, Megan; Hussein, Zekarias; Hanasaki, Naota; Mauzerall, Denise; Rodriguez-Iturbe, Ignacio

    2014-05-01

    The international trade of food commodities links water and food systems, with important implications for both water and food security. The embodied water resources associated with food trade are referred to as `virtual water trade'. We present the first study of the impact of climate change on global virtual water trade flows and associated savings for the year 2030. In order to project virtual water trade and savings under climate change, it is essential to obtain projections of both bilateral crop trade and the virtual water content of crops in each country of production. We use the Global Trade Analysis Project model to estimate bilateral crop trade under changes in agricultural productivity for rice, soy, and wheat. We use the H08 global hydrologic model to determine the impact of climatic changes to crop evapotranspiration for rice, soy, and wheat in each country of production. Then, we combine projections of bilateral crop trade with estimates of virtual water content to obtain virtual water trade flows under climate change. We find that the total volume of virtual water trade is likely to go down under climate change, due to decreased crop trade from higher crop prices under scenarios of declining crop yields and due to decreased virtual water content under high agricultural productivity scenarios. However, the staple food trade is projected to save more water across most climate change scenarios, largely because the wheat trade re-organizes into a structure where large volumes of wheat are traded from relatively water-efficient exporters to less efficient importers.

  9. CFD Numerical Simulation of the Complex Turbulent Flow Field in an Axial-Flow Water Pump

    Directory of Open Access Journals (Sweden)

    Wan-You Li

    2014-09-01

    Full Text Available Further optimal design of an axial-flow water pump calls for a thorough recognition of the characteristics of the complex turbulent flow field in the pump, which is however extremely difficult to be measured using the up-to-date experimental techniques. In this study, a numerical simulation procedure based on computational fluid dynamics (CFD was elaborated in order to obtain the fully three-dimensional unsteady turbulent flow field in an axial-flow water pump. The shear stress transport (SST k-ω model was employed in the CFD calculation to study the unsteady internal flow of the axial-flow pump. Upon the numerical simulation results, the characteristics of the velocity field and pressure field inside the impeller region were discussed in detail. The established model procedure in this study may provide guidance to the numerical simulations of turbomachines during the design phase or the investigation of flow and pressure field characteristics and performance. The presented information can be of reference value in further optimal design of the axial-flow pump.

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

    Science.gov (United States)

    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.

  11. Role of adventitious roots in water relations of tamarack (Larix laricina seedlings exposed to flooding

    Directory of Open Access Journals (Sweden)

    Calvo-Polanco Mónica

    2012-06-01

    Full Text Available Abstract Background Flooding reduces supply of oxygen to the roots affecting plant water uptake. Some flooding-tolerant tree species including tamarack (Larix laricina (Du Roi K. Koch produce adventitious roots in response to flooding. These roots were reported to have higher hydraulic conductivity under flooding conditions compared with non-adventitious roots. In the present study, we examined structural and functional modifications in adventitious roots of tamarack seedlings to explain their flooding tolerance. Results Seedlings were subjected to the flooding treatment for six months, which resulted in an almost complete disintegration of the existing root system and its replacement with adventitious roots. We compared gas exchange parameters and water relations of flooded plants with the plants growing in well-drained soil and examined the root structures and root water transport properties. Although flooded seedlings had lower needle chlorophyll concentrations, their stomatal conductance, net photosynthesis rates and shoot water potentials were similar to non-flooded plants, indicative of flooding tolerance. Flooded adventitious roots had higher activation energy and a higher ratio of apoplastic to cell-to-cell water flow compared with non-flooded control roots as determined with the 1-hydroxypirene 3,6,8-trisulfonic acid apoplastic tracer dye. The adventitious roots in flooded plants also exhibited retarded xylem and endodermal development and accumulated numerous starch grains in the cortex. Microscopic examination of root sections treated with the PIP1 and PIP2 antibodies revealed high immunoreactivity in the cortex of non-flooded roots, as compared with flooded roots. Conclusions Structural modifications of adventitious roots suggest increased contribution of apoplastic bypass to water flow. The reduced dependence of roots on the hypoxia-sensitive aquaporin-mediated water transport is likely among the main mechanisms allowing tamarack

  12. Reduction of large-scale numerical ground water flow models

    NARCIS (Netherlands)

    Vermeulen, P.T.M.; Heemink, A.W.; Testroet, C.B.M.

    2002-01-01

    Numerical models are often used for simulating ground water flow. Written in state space form, the dimension of these models is of the order of the number of model cells and can be very high (> million). As a result, these models are computationally very demanding, especially if many different scena

  13. Soil surfactant stops water repellency and preferential flow paths

    NARCIS (Netherlands)

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

    2008-01-01

    This study reports the effects of a soil surfactant on reduction and prevention of water repellency and preferential flow paths in a sandy soil of a golf course fairway, located at Bosch en Duin near Utrecht, the Netherlands. The golf course is constructed on inland dunes composed of fine sand with

  14. Continuum simulations of water flow past fullerene molecules

    DEFF Research Database (Denmark)

    Popadic, A.; Praprotnik, M.; Koumoutsakos, P.;

    2015-01-01

    We present continuum simulations of water flow past fullerene molecules. The governing Navier-Stokes equations are complemented with the Navier slip boundary condition with a slip length that is extracted from related molecular dynamics simulations. We find that several quantities of interest as ...

  15. Streamline curvature and bed resistance in shallow water flow

    NARCIS (Netherlands)

    De Vriend, H.J.

    1979-01-01

    The relationship between streamline curvature and bed resistance in shallow water flow with little side constraint, as derived in 1970 by H.J. Schoemaker, is reconsidered. Schoemaker concluded that the bed resistance causes the curvature of a free streamline to grow exponentially with the distance a

  16. Hydrogel Regulation of Xylem Water Flow: An Alternative Hypothesis

    NARCIS (Netherlands)

    Doorn, van W.G.; Hiemstra, T.; Fanourakis, D.

    2011-01-01

    The concentration of cations in the xylem sap influences the rate of xylem water flow in angiosperm plants. It has been speculated that this is due to the shrinking and swelling of pectins in the pit membranes. However, there is as yet minimal evidence for the presence of pectin in pit membranes of

  17. Continuum simulations of water flow in carbon nanotube membranes

    DEFF Research Database (Denmark)

    Popadić, A.; Walther, Jens Honore; Koumoutsakos, P-

    2014-01-01

    We propose the use of the Navier–Stokes equations subject to partial-slip boundary conditions to simulate water flows in Carbon NanoTube (CNT) membranes. The finite volume discretizations of the Navier–Stokes equations are combined with slip lengths extracted from molecular dynamics (MD) simulati......We propose the use of the Navier–Stokes equations subject to partial-slip boundary conditions to simulate water flows in Carbon NanoTube (CNT) membranes. The finite volume discretizations of the Navier–Stokes equations are combined with slip lengths extracted from molecular dynamics (MD...... that flows at nanoscale channels can be described by continuum solvers with proper boundary conditions that reflect the molecular interactions of the liquid with the walls of the nanochannel....

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  1. Flow and cavitation characteristics of water hydraulic poppet valves

    Institute of Scientific and Technical Information of China (English)

    廖义德; 刘银水; 黄艳; 李壮云

    2002-01-01

    Two types of poppet valves were tested, one is a poppet with a sharp-edged seats, and the other is that with a chamfered seat. During the tests, the effects of backpressure and poppet lift on flow characteristics were considered. Cavitation inception was detected by the appearance and rapid growth of a particular low frequency component of the outlet pressure fluctuation of valve when cavitation occurs. Experimental results show cavitation, back pressure, valve opening and its geometrical shape have significant effects on the flow characteristics of valve. The flow coefficient of throttle with water used as working medium is 0. 85~0. 95 when there is no cavitation. The pressure drop of flow saturation decreases with the increasing of poppet lift. The sharp-edged throttle has stronger anti-cavitation ability than the chamfered one.

  2. Stability of shear shallow water flows with free surface

    CERN Document Server

    Chesnokov, Alexander; Gavrilyuk, Sergey; Pavlov, Maxim

    2016-01-01

    Stability of inviscid shear shallow water flows with free surface is studied in the framework of the Benney equations. This is done by investigating the generalized hyperbolicity of the integrodifferential Benney system of equations. It is shown that all shear flows having monotonic convex velocity profiles are stable. The hydrodynamic approximations of the model corresponding to the classes of flows with piecewise linear continuous and discontinuous velocity profiles are derived and studied. It is shown that these approximations possess Hamiltonian structure and a complete system of Riemann invariants, which are found in an explicit form. Sufficient conditions for hyperbolicity of the governing equations for such multilayer flows are formulated. The generalization of the above results to the case of stratified fluid is less obvious, however, it is established that vorticity has a stabilizing effect.

  3. Computational Agents For Flows: Waterballs, Water Paths and Ponds

    Science.gov (United States)

    Servat, D.; Leonard, J.; Perrier, E.

    For the past four years, the RIVAGE project has been an ongoing methodological re- search involving both computer scientists from LIP6 and hydrologists from research unit GEODES at IRD around the question of applying DAI and agent-based simula- tion techniques to environmental water flow modeling. It led us to design an agent- based simulation environment which is intended to model coupled runoff dynamics, infiltration and erosion processes, so as to integrate heterogeneous events occuring at different time and space scales. A main feature of this modeling approach is the ability to account for a structured vision of the hydrological network produced during rainfall, much like that of an on field observer : for instance, when water accumulates in topographic depressions, the simulator creates pond objects, and when stable wa- ter paths emerge, water path objects are created. Beside this vision of water flow, the natural environment itself can be given a structured representation of natural objects (e.g. vegetation, infiltration maps, furrow or ditch networks, macropore patterns, etc.) which belong to various information layers. According to the scale of study, these layers may contain different types of geometrical and geographical data. Given that, our long term objective is to simulate the influence of spatial structurations of the environment on water flow dynamics and vice versa.

  4. Nitrogen compounds in the apoplastic sap of sugarcane stem: some implications in the association with endophytes.

    Science.gov (United States)

    Tejera, Noel; Ortega, Eduardo; Rodes, Rosa; Lluch, Carmen

    2006-01-01

    Several nitrogen compounds were identified and quantified in the apoplastic and symplastic sap of sugarcane stems. The sap of stems was composed mainly of soluble sugars, which constituted 95% of the total organic compounds detected. Sap also contained nitrogen compounds, with amino acids (50-70% of N) and proteins (20-30% of N), being the main nitrogenous substances, as well as inorganic forms as ammonium, nitrite and nitrate, in low concentrations (Gluconacetobacter diazotrophicus. The total amino acid content of apoplastic sap was six to nine times lower in non-nitrogen fertilized plants than in fertilized ones. The possible roles of these substances to regulate endophytic associations with sugarcane are also discussed.

  5. 76 FR 79604 - Effective Date for the Water Quality Standards for the State of Florida's Lakes and Flowing Waters

    Science.gov (United States)

    2011-12-22

    ... AGENCY 40 CFR Part 131 RIN 2040-AF36 Effective Date for the Water Quality Standards for the State of... of the ``Water Quality Standards for the State of Florida's Lakes and Flowing Waters; Final Rule... for the ``Water Quality Standards for the State of Florida's Lakes and Flowing Waters; Final...

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

    Energy Technology Data Exchange (ETDEWEB)

    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. Spatial development of the wind-driven water surface flow

    Science.gov (United States)

    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

  8. Continuous-Flow System Produces Medical-Grade Water

    Science.gov (United States)

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

    Science.gov (United States)

    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

  10. Numerical simulation and analysis of water flow over stepped spillways

    Institute of Scientific and Technical Information of China (English)

    AMADOR; António

    2009-01-01

    Numerical simulation of water flow over the stepped spillway is conducted using Mixture multiphase flow model. Different turbulence models are chosen to enclose the controlling equations. The turbulence models investigated are realizable k-ε model, SST k-ω model, v2-f model and LES model. The computational results by the four turbulence models are compared with experimental ones in the following aspects: mean velocity, the spanwise vorticity and the growth of the turbulent boundary layer thickness in the streamwise direction. It is found from the comparison that the realizable k-ε model, in which the rotation tensor is included, shows good performance for simulation of flows involving rotation, boundary layer and recirculation. The realizable k-ε model is the most efficient in simulating flow over stepped spillways. Further, the characteristics of water flow on the stepped spillway are studied in terms of the mean velocity profile normal to the pseudo-bottom and the pressure field on the steps based on the simulation results using realizable k-ε model.

  11. Numerical simulation and analysis of water flow over stepped spillways

    Institute of Scientific and Technical Information of China (English)

    QIAN ZhongDong; HU XiaoQing; HUAI WenXin; AMADOR António

    2009-01-01

    Numerical simulation of water flow over the stepped spillway is conducted using Mixture multiphase flow model. Different turbulence models are chosen to enclose the controlling equations. The turbulence models investigated are realizable k-ε model, SST k-ω model, v2-f model and LES model. The computational results by the four turbulence models are compared with experimental ones in the following aspects: mean velocity, the spanwise vorticity and the growth of the turbulent boundary layer thickness in the streamwise direction. It is found from the comparison that the realizable k-ε model, in which the rotation tensor is included, shows good performance for simulation of flows involving rotation, boundary layer and recirculation. The realizable k-e model is the most efficient in simulating flow over stepped spillways. Further, the characteristics of water flow on the stepped spillway are studied in terms of the mean velocity profile normal to the pseudo-bottom and the pressure field on the steps based on the simulation results using realizable k-ε model.

  12. Local properties of countercurrent stratified steam-water flow

    Energy Technology Data Exchange (ETDEWEB)

    Kim, H J

    1985-10-01

    A study of steam condensation in countercurrent stratified flow of steam and subcooled water has been carried out in a rectangular channel/flat plate geometry over a wide range of inclination angles (4/sup 0/-87/sup 0/) at several aspect ratios. Variables were inlet water and steam flow rates, and inlet water temperature. Local condensation rates and pressure gradients were measured, and local condensation heat transfer coefficients and interfacial shear stress were calculated. Contact probe traverses of the surface waves were made, which allowed a statistical analysis of the wave properties. The local condensation Nusselt number was correlated in terms of local water and steam Reynolds or Froude numbers, as well as the liquid Prandtl number. A turbulence-centered model developed by Theofanous, et al. principally for gas absorption in several geometries, was modified. A correlation for the interfacial shear stress and the pressure gradient agreed with measured values. Mean water layer thicknesses were calculated. Interfacial wave parameters, such as the mean water layer thickness, liquid fraction probability distribution, wave amplitude and wave frequency, are analyzed.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    DEFF Research Database (Denmark)

    Walther, J. H.; Popadic, A.; Koumoutsakos, P.

    We present continuum simulations of water flow past fullerene molecules. The governing Navier-Stokes equations are complemented with the Navier slip bound-ary condition with a slip length that is extracted from related molecular dynamics simulations. We find that several quantities of interest...

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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

  18. Hyperconcentrated flows as influenced by coupled wind-water processes

    Institute of Scientific and Technical Information of China (English)

    XU; Jiongxin

    2005-01-01

    Using data from more than 40 rivers in the middle Yellow River basin, a study has been made of the influence of coupled wind-water processes on hyperconcentrated flows. A simple "vehicle" model has been proposed to describe hyperconcentrated flows. The liquid phase of two-phase flows is a "vehicle", in which coarse sediment particles are carried as solid-phase. The formation and characteristics of hyperconcentrated flows are closely related with the formation and characteristics of this liquid-phase and solid-phase. Surface materials and geomorphic agents of the middle Yellow River basin form some patterns of combination, which have deep influence on the formation and characteristics of liquid- and solid-phases of hyperconcentrated flows. The combination of high percentages of relatively coarse material with low percentages of fine material appears in the area predominated by the wind process, where the supply of relatively coarse sediment is sufficient, but the supply of relatively coarse sediment is not. The combination of low percentages of relatively coarse material with high percentages of fine material appears in the area predominated by the water process, where the supply of fine sediment is sufficient, but the supply of fine sediment is not. In the area predominated by coupled wind-water processes appears the combination of medium percentages of coarse and fine materials, and thus both coarse and fine sediments are in relatively sufficient supply. The manner in which the mean annual sediment concentrations of liquid- and solid-phases vary with total suspended sediment concentration is different. With the increased total suspended sediment concentration, mean annual sediment concentration of liquid-phase increased to a limit and then remained constant; however, mean annual sediment concentrations of solid-phase increased continuously. Thus, the magnitude of total suspended sediment concentration depends on the supply conditions of relatively coarse sediment

  19. Evaluation of heat and water flow in porosity permeable horizons

    Science.gov (United States)

    Pasquale, Vincenzo; Verdoya, Massimo; Chiozzi, Paolo

    2010-05-01

    Several strategies have been developed to explore the circulation of geofluids, which can yield heat transport over large spatial scales. Groundwater flow from recharge areas, where precipitation seeps downwards beneath the ground surface and reaches the saturated zone, to discharge areas, where subsurface water is discharged to streams, lakes, ponds or swamps, forms an additional mechanism of heat transfer to pure conduction, which is generally assumed for the underground thermal regime. In this paper we discuss and apply two different analytical models of heat and water flow, both valid for steady-state thermal conditions and for uniform, isotropic, homogeneous, and saturated porous media. By combining conductive and groundwater advective heat transfer, a first model assumes heat and water flow in vertical direction and neglects thermal gradient along the horizontal. The thermal field is influenced only by the flow of water parallel to the thermal gradient, whereas perpendicular water flow if any has no effect. Because most layers are sloping and because surface topographic relief usually exists across the aquifer, usually isotherms are not horizontal. Hence, we applied a second model for heat and water flow, neither purely horizontal nor purely vertical. In the governing equation of heat conduction-advection we take account of the horizontal flow of heat and water. The flow rate is assumed to be constant and sufficient small that thermal equilibrium is maintained between the water and the rock matrix. Examples of application are given for a set of boreholes drilled for geothermal exploration. Hydrothermal parameters (vertical and horizontal components of the Darcy velocity and the Péclet number) are determined by matching temperature and thermal gradient versus depth data with the two models. Thermal information is completed by a set of thermal conductivity measurements carried out on core samples recovered during drillings. The analysed underground

  20. Nonlinear analysis of gas-water/oil-water two-phase flow in complex networks

    CERN Document Server

    Gao, Zhong-Ke; Wang, Wen-Xu

    2014-01-01

    Understanding the dynamics of multi-phase flows has been a challenge in the fields of nonlinear dynamics and fluid mechanics. This chapter reviews our work on two-phase flow dynamics in combination with complex network theory. We systematically carried out gas-water/oil-water two-phase flow experiments for measuring the time series of flow signals which is studied in terms of the mapping from time series to complex networks. Three network mapping methods were proposed for the analysis and identification of flow patterns, i.e. Flow Pattern Complex Network (FPCN), Fluid Dynamic Complex Network (FDCN) and Fluid Structure Complex Network (FSCN). Through detecting the community structure of FPCN based on K-means clustering, distinct flow patterns can be successfully distinguished and identified. A number of FDCN’s under different flow conditions were constructed in order to reveal the dynamical characteristics of two-phase flows. The FDCNs exhibit universal power-law degree distributions. The power-law exponent ...

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

    Science.gov (United States)

    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.

  2. DspA/E contributes to apoplastic accumulation of ROS in nonhost A. thaliana

    Directory of Open Access Journals (Sweden)

    Alban eLaunay

    2016-04-01

    Full Text Available The bacterium Erwinia amylovora is responsible for the fire blight disease of Maleae, which provokes necrotic symptoms on aerial parts. The pathogenicity of this bacterium in hosts relies on its type three-secretion system (T3SS, a molecular syringe that allows the bacterium to inject effectors into the plant cell. E. amylovora-triggered disease in host plants is associated with the T3SS-dependent production of reactive oxygen species (ROS, although ROS are generally associated with resistance in other pathosystems. We showed previously that E. amylovora can multiply transiently in the nonhost plant Arabidopsis thaliana and that a T3SS-dependent production of intracellular ROS occurs during this interaction. In the present work we characterize the localization and source of hydrogen peroxide accumulation following E. amylovora infection. Transmission electron microscope (TEM analysis of infected tissues showed that hydrogen peroxide accumulation occurs in the cytosol, plastids, peroxisomes, and mitochondria as well as in the apoplast. Furthermore, TEM analysis showed that an E. amylovora dspA/E-deficient strain does not induce hydrogen peroxide accumulation in the apoplast. Consistently, a transgenic line expressing DspA/E accumulated ROS in the apoplast. The NADPH oxidase-deficient rbohD mutant showed a very strong reduction in hydrogen peroxide accumulation in response to E. amylovora inoculation. However, we did not find an increase in bacterial titers of E. amylovora in the rbohD mutant and the rbohD mutation did not suppress the toxicity of DspA/E when introgressed into a DspA/E-expressing transgenic line. Co-inoculation of E. amylovora with cycloheximide (CHX, which we found previously to suppress callose deposition and allow strong multiplication of E. amylovora in A. thaliana leaves, led to a strong reduction of apoplastic ROS accumulation but did not affect intracellular ROS. Our data strongly suggest that apoplastic ROS accumulation is

  3. Relating water and air flow characteristics in coarse granular materials

    DEFF Research Database (Denmark)

    Andreasen, Rune Røjgaard; Canga, Eriona; Poulsen, Tjalfe Gorm

    2013-01-01

    Water pressure drop as a function of velocity controls w 1 ater cleaning biofilter operation 2 cost. At present this relationship in biofilter materials must be determined experimentally as no 3 universal link between pressure drop, velocity and filter material properties have been established. 4...... Pressure drop - velocity in porous media is much simpler and faster to measure for air than for water. 5 For soils and similar materials, observations show a strong connection between pressure drop – 6 velocity relations for air and water, indicating that water pressure drop – velocity may be estimated 7...... from air flow data. The objective of this study was, therefore, to investigate if this approach is valid 8 also for coarse granular biofilter media which usually consists of much larger particles than soils. In 9 this paper the connection between the pressure drop – velocity relationships for air...

  4. Flow structure from a horizontal cylinder coincident with a free surface in shallow water flow

    Directory of Open Access Journals (Sweden)

    Kahraman Ali

    2012-01-01

    Full Text Available Vortex formation from a horizontal cylinder coincident with a free surface of a shallow water flow having a depth of 25.4 [mm] was experimentally investigated using the PIV technique. Instantaneous and time-averaged flow patterns in the wake region of the cylinder were examined for three different cylinder diameter values under the fully developed turbulent boundary layer condition. Reynolds numbers were in the range of 1124£ Re£ 3374 and Froude numbers were in the range of 0.41 £ Fr £ 0.71 based on the cylinder diameter. It was found that a jet-like flow giving rise to increasing the flow entrainment between the core and wake regions depending on the cylinder diameter was formed between the lower surface of the cylinder and bottom surface of the channel. Vorticity intensity, Reynolds stress correlations and the primary recirculating bubble lengths were grown to higher values with increasing the cylinder diameter. On the other hand, in the case of the lowest level of the jet-like flow emanating from the beneath of the smallest cylinder, the variation of flow characteristics were attenuated significantly in a shorter distance. The variation of the reattachment location of the separated flow to the free-surface is a strong function of the cylinder diameter and the Froude number.

  5. Ground-water flow and quality near Canon City, Colorado

    Science.gov (United States)

    Hearne, G.A.; Litke, D.W.

    1987-01-01

    Water in aquifers that underlie the Lincoln Park area near Canon City, Colorado, contains measurable concentrations of chemical constituents that are similar to those in raffinate (liquid waste) produced by a nearby uranium ore processing mill. The objective of this study was to expand the existing geohydrologic data base by collecting additional geohydrologic and water quality, in order to refine the description of the geohydrologic and geochemical systems in the study area. Geohydrologic data were collected from nine tests wells drilled in the area between the U.S. Soil Conservation Service dam and Lincoln Park. Lithologic and geophysical logs of these wells indicated that the section of Vermejo Formation penetrated consisted of interbedded sandstone and shale. The sandstone beds had a small porosity and small hydraulic conductivity. Groundwater flow from the U.S. Soil Conservation Service dam to Lincoln Park seemed to be along an alluvium-filled channel in the irregular and relatively undescribed topography of the Vermejo Formation subcrop. North of the De Weese Dye Ditch, the alluvium becomes saturated and groundwater generally flows to the northeast. Water samples from 28 sites were collected and analyzed for major ions and trace elements; selected water samples also were analyzed for stable isotopes; samples were collected from wells near the uranium ore processing mill, from privately owned wells in Lincoln Park, and from the test wells drilled in the intervening area. Results from the quality assurance samples indicate that cross-contamination between samples from different wells was avoided and that the data are reliable. Water in the alluvial aquifer underlying Lincoln Park is mainly a calcium bicarbonate type. Small variations in the composition of water in the alluvial aquifer appears to result from a reaction of water leaking from the De Weese Dye Ditch with alluvial material. Upward leakage from underlying aquifers does not seem to be significant in

  6. Dinoflagellate bioluminescence in response to mechanical stimuli in water flows

    Directory of Open Access Journals (Sweden)

    A. S. Cussatlegras

    2005-01-01

    Full Text Available Bioluminescence of plankton organisms induced by water movements has long been observed and is still under investigations because of its great complexity. In particular, the exact mechanism occurring at the level of the cell has not been yet fully understood. This work is devoted to the study of the bioluminescence of the dinoflagellates plankton species Pyrocystis noctiluca in response to mechanical stimuli generated by water flows. Several experiments were performed with different types of flows in a Couette shearing apparatus. All of them converge to the conclusion that stationary homogeneous laminar shear does not trigger massive bioluminescence, but that acceleration and shear are both necessary to stimulate together an intense bioluminescence response. The distribution of the experimental bioluminescence thresholds is finally calculated from the light emission response for the Pyrocystis noctiluca species.

  7. ABRUPT DEFLECTED SUPERCRITICAL WATER FLOW IN SLOPED CHANNELS

    Institute of Scientific and Technical Information of China (English)

    LIU Ya-kun; NI Han-gen

    2008-01-01

    The effect of the bottom slope on abrupt deflected supercritical water flow was experimentally and theoretically studied. Model tests were conducted in a flume of 1.2 m wide and 2.6 m long with sloped bottom at an angle 35.54o, its length of deflector was 0.2 m and the deflection angles were 15o and 30o. An approximate method for calculatjng the shock wave angle and depth ratio of the abrupt deflected supercritical water flow was suggested, and a correction coefficient for the hydrodynamic pressure was introduced to generalize the momentum equation in the direction perpendicular to the shock front. It must be noticed that in the sloped channel the shock wave angle and the depth ratio are no longer constant as those in the horizontal channels, but slowly change along the shock front. The calculated results are in good agreement with measured data.

  8. Experimental investigation of flow-structure interaction between a model biofilm streamer and water flow

    Science.gov (United States)

    Kazemifar, Farzan; Blois, Gianluca; Sinha, Sumit; Hardy, Richard; Best, James; Sambrook Smith, Gregory; Christensen, Kenneth

    2016-11-01

    Biofilms are permeable and deformable material whose bulk structure is composed of extracellular polymeric substance (EPS) that houses bacterial colonies. The EPS is responsible for the mechanical properties of the biofilm. In this study we investigate the fluid-structure interaction between a model biofilm streamer and water flow in a closed-loop water channel in the laminar and transitional flow regimes, using the particle image velocimetry (PIV) technique. The model streamer is fabricated from acrylamide polymer hydrogel. The purpose for using this material is twofold: 1) its mechanical properties (i.e. elastic modulus) can be tuned by controlling its chemical composition, 2) the hydrogel is transparent with a refractive index (RI) very close to that of water, thus minimizing the optical distortions for flow visualization. The velocity vector fields obtained from PIV measurements are used to investigate the temporal evolution of the flow structure in the vicinity of the streamer, focusing on the vortex shedding mechanism and the resulting oscillations of the streamer.

  9. 75 FR 45579 - Water Quality Standards for the State of Florida's Lakes and Flowing Waters; Supplemental Notice...

    Science.gov (United States)

    2010-08-03

    ... AGENCY 40 CFR Part 131 RIN 2040-AF11 Water Quality Standards for the State of Florida's Lakes and Flowing... 26, 2010, notice of proposed rulemaking (NPRM), proposing numeric nutrient water quality criteria to..., ``Water Quality Standards for the State of Florida's Lakes and Flowing Waters.'' This supplemental...

  10. 77 FR 74449 - Water Quality Standards for the State of Florida's Lakes and Flowing Waters; Proposed Rule; Stay

    Science.gov (United States)

    2012-12-14

    ... AGENCY 40 CFR Part 131 RIN 2040-AF41 Water Quality Standards for the State of Florida's Lakes and Flowing... regulation the ``Water Quality Standards for the State of Florida's Lakes and Flowing Waters; Final Rule... Information Does this action apply to me? Citizens concerned with water quality in Florida may be...

  11. Water flow simulation and analysis in HMA microstructure

    Directory of Open Access Journals (Sweden)

    Can Chen

    2014-10-01

    Full Text Available This paper introduces a new method for reconstructing virtual two-dimensional (2-D microstructure of hot mix asphalt (HMA. Based on the method, the gradation of coarse aggregates and the film thickness of the asphalt binder can be defined by the user. The HMA microstructure then serves as the input to the computational fluid dynamic (CFD software (ANSYS-FLUENT to investigate the water flow pattern through it. It is found that the realistic flow fields can be simulated in the 2-D micro-structure and the flow patterns in some typical air void structures can be identified. These flow patterns can be used to explain the mechanism that could result in moisture damage in HMA pavement. The one-dimensional numerical permeability values are also derived from the flow fields of the 2-D HMA microstructure and compared with the measured values obtained by the Karol-Warner permeameter. Because the interconnected air voids channels in actual HMA samples cannot be fully represented in a 2-D model, some poor agreements need to be improved.

  12. Continuum Simulations of Water Flow in Carbon Nanotube Membranes

    Science.gov (United States)

    Walther, J. H.; Popadic, A.; Koumoutsakos, P.; Praprotnik, M.

    2014-11-01

    We propose the use of the Navier-Stokes equations subject to partial-slip boundary conditions to simulate water flows in Carbon NanoTube (CNT) membranes. The finite volume discretisations of the Navier-Stokes equations are combined with slip lengths extracted from Molecular Dynamics (MD) simulations to predict the pressure losses at the CNT entrance as well as the enhancement of the flow rate in the CNT. The flow quantities calculated from the present hybrid approach are in excellent agreement with pure MD results while they are obtained at a fraction of the computational cost. The method enables simulations of system sizes and times well beyond the present capabilities of MD simulations. Our simulations provide an asymptotic flow rate enhancement and indicate that the pressure losses at the CNT ends can be reduced by reducing their curvature. More importantly, our results suggest that flows at nanoscale channels can be described by continuum solvers with proper boundary conditions that reflect the molecular interactions of the liquid with the walls of the nanochannel.

  13. Water flow boiling behaviors in hydrophilic and hydrophobic microchannels

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Chiwoong; Yu, Dongin; Kim, Moohwan [Pohang University of Science and Technology (Korea, Republic of). Dept. of Mechanical Engineering

    2009-07-01

    The wettability is one of issues on two-phase flow in a microchannel. However, previous studies of wettability effect on two-phase flow have conducted only isothermal condition. Moreover, most studies have used conventional micro/mini-tubes due to difficulties of their fabrication. The objective of our study is to understand the wettability effect on flow boiling in a rectangular microchannel. In the first, new micro-electro-mechanical-system (MEMS) fabrication technique was developed to obtain a single glass rectangular microchannel and localized six micro heaters. A photosensitive glass was used as base material. The photosensitive glass is hydrophilic, so the hydrophobic microchannel was prepared by coating SAM, flow boiling experiments were conducted in hydrophilic and hydrophobic microchannels with micro heaters. The experiment range was the mass flux of 25 and 75 kg/m{sup 2}s, the heat flux of 30 - 430 k W/m2 and quality of 0 - 0.3. A working fluid was de-ionized and degassed water. The local heat transfer coefficient was evaluated at the local micro heater section. Also, flow regimes in the microchannel were visualized by using a high-speed camera with a long-distance microscope. Heat transfer was analyzed with visualization results. Heat transfer in the hydrophobic microchannel was enhanced by higher nucleation site density and delayed local dryout. The pressure drop in the hydrophobic microchannel was higher than that in the hydrophilic microchannel. (author)

  14. Effects of rainfall on water quality in six sequentially disposed fishponds with continuous water flow

    Directory of Open Access Journals (Sweden)

    LH. Sipaúba-Tavares

    Full Text Available An investigation was carried out during the rainy period in six semi-intensive production fish ponds in which water flowed from one pond to another without undergoing any treatment. Eight sampling sites were assigned at pond outlets during the rainy period (December-February. Lowest and highest physical and chemical parameters of water occurred in pond P1 (a site near the springs and in pond P4 (a critical site that received allochthonous material from the other ponds and also from frog culture ponds, respectively. Pond sequential layout caused concentration of nutrients, chlorophyll-a and conductivity. Seasonal rains increased the water flow in the ponds and, consequently, silted more particles and other dissolved material from one fish pond to another. Silting increased limnological variables from P3 to P6. Although results suggest that during the period under analysis, rainfall affected positively the ponds' water quality and since the analyzed systems have been aligned in a sequential layout with constant water flow from fish ponds and parallel tanks without any previous treatment, care has to be taken so that an increase in rain-induced water flow does not have a contrary effect in the fish ponds investigated.

  15. EFFECT OF SURFACTANT ON TWO-PHASE FLOW PATTERNS OF WATER-GAS IN CAPILLARY TUBES

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Flow patterns of liquid-gas two-phase flow were experimentally investigated. The experiments were carried out in both vertical and horizontal capillary tubes having inner diameters of 1.60 mm. The working liquid was the mixture of water and Sodium Dodecyl Benzoyl Sulfate (SDBS). The working gas was Nitrogen. For the water/SDBS mixture-gas flow in the vertical capillary tube, flow-pattern transitions occurred at lower flow velocities than those for the water-gas flow in the same tube. For the water/SDBS mixture-gas flow in the horizontal capillary tube, surface tension had little effect on the bubbly-intermittent transition and had only slight effect on the plug-slug and slug-annular transitions. However, surface tension had significant effect on the wavy stratified flow regime. The wavy stratified flow regime of water/SDBS mixture-gas flow expanded compared with that of water-gas.

  16. Tomography of ground water flow from self-potential data

    Science.gov (United States)

    Revil, A.; Jardani, A.

    2007-12-01

    An inversion algorithm is developed to interpret self-potential (SP) data in terms of distribution of the seepage velocity of the ground water. The model is based on the proportionality existing between the electrokinetic source current density and the seepage velocity of the water phase. As the inverse problem is underdetermined, we use a Tikhonov regularization method with a smoothness constraint based on the differential Laplacian operator to solve the inverse problem. The regularization parameter is determined by the L-shape method. The recovery of the distribution of the seepage velocity vector of the ground water flow depends on the localization and number of non-polarizing electrodes and information relative to the distribution of the electrical resistivity of the ground. The inversion method is tested on two 2D synthetic cases and on two real SP data. The first field test corresponds to the infiltration of water from a ditch. The second one corresponds to large flow at the Cerro Prieto geothermal field in Baja California.

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

    Science.gov (United States)

    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.

  18. Altitudes of the top of model layers for the transient ground-water flow model, Death Valley regional ground-water flow system, Nevada and California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This digital data set defines the altitudes of the tops of 16 model layers simulated in the Death Valley regional ground-water flow system (DVRFS) transient flow...

  19. Numerical study of saturation steam/water mixture flow and flashing initial sub-cooled water flow inside throttling devices

    CERN Document Server

    CERN. Geneva

    2016-01-01

    In this work, a Computational Fluid-Dynamics (CFD) approach to model this phenomenon inside throttling devices is proposed. To validate CFD results, different nozzle geometries are analyzed, comparing numerical results with experimental data. Two cases are studied: Case 1: saturation steam/water mixture flow inside 2D convergent-divergent nozzle (inlet, outlet and throat diameter of nozzle are 0.1213m, 0.0452m and 0.0191m respectively). In this benchmark, a range of total inle...

  20. Water Resource Inventory and Assessment - Flow Map Poster: William L. Finley National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This flow map depicts the flow and control of water on William L. Finley National Wildlife Refuge. It was produced as part of the Water Resource Inventory and...

  1. Water Resource Inventory and Assessment - Flow Map Poster: Baskett Slough National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This flow map depicts the flow and control of water on Baskett Slough National Wildlife Refuge. It was produced as part of the Water Resource Inventory and...

  2. Water Resource Inventory and Assessment - Flow Map Poster: Ankeny National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This flow map depicts the flow and control of water on Ankeny National Wildlife Refuge. It was produced as part of the Water Resource Inventory and Assessment...

  3. Subregions of the Death Valley regional ground-water flow system, Nevada and California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This digital data set defines the subregions of the transient ground-water flow model of the Death Valley regional ground-water flow system (DVRFS). Subregions are...

  4. Water flow exchange characteristics in coarse granular filter media

    DEFF Research Database (Denmark)

    Andreasen, Rune Røjgaard; Pugliese, Lorenzo; Poulsen, Tjalfe

    2013-01-01

    in this study are performed at a concurrent airflow of 0.3 m s−1, water irrigation rates of 1–21 cm h−1 in materials with particle diameters ranging from 2 to 14 mm to represent media and operation conditions relevant for low flow biotrickling filter design. Specific surface area related elution velocity...... distribution was closely related to the filter water content, water irrigation rate, media specific surface area and particle size distribution. A predictive model linking the specific surface area related elution velocity distribution to irrigation rate, specific surface area and particle size distribution......Elution of inhibitory metabolites is a key parameter controlling the efficiency of air cleaning bio- and biotrickling filters. To the authors knowledge no studies have yet considered the relationship between specific surface area related elution velocity and physical media characteristics, which...

  5. Contrasting Roles of the Apoplastic Aspartyl Protease APOPLASTIC, ENHANCED DISEASE SUSCEPTIBILITY1-DEPENDENT1 and LEGUME LECTIN-LIKE PROTEIN1 in Arabidopsis Systemic Acquired Resistance.

    Science.gov (United States)

    Breitenbach, Heiko H; Wenig, Marion; Wittek, Finni; Jordá, Lucia; Maldonado-Alconada, Ana M; Sarioglu, Hakan; Colby, Thomas; Knappe, Claudia; Bichlmeier, Marlies; Pabst, Elisabeth; Mackey, David; Parker, Jane E; Vlot, A Corina

    2014-04-22

    Systemic acquired resistance (SAR) is an inducible immune response that depends on ENHANCED DISEASE SUSCEPTIBILITY1 (EDS1). Here, we show that Arabidopsis (Arabidopsis thaliana) EDS1 is required for both SAR signal generation in primary infected leaves and SAR signal perception in systemic uninfected tissues. In contrast to SAR signal generation, local resistance remains intact in eds1 mutant plants in response to Pseudomonas syringae delivering the effector protein AvrRpm1. We utilized the SAR-specific phenotype of the eds1 mutant to identify new SAR regulatory proteins in plants conditionally expressing AvrRpm1. Comparative proteomic analysis of apoplast-enriched extracts from AvrRpm1-expressing wild-type and eds1 mutant plants led to the identification of 12 APOPLASTIC, EDS1-DEPENDENT (AED) proteins. The genes encoding AED1, a predicted aspartyl protease, and another AED, LEGUME LECTIN-LIKE PROTEIN1 (LLP1), were induced locally and systemically during SAR signaling and locally by salicylic acid (SA) or its functional analog, benzo 1,2,3-thiadiazole-7-carbothioic acid S-methyl ester. Because conditional overaccumulation of AED1-hemagglutinin inhibited SA-induced resistance and SAR but not local resistance, the data suggest that AED1 is part of a homeostatic feedback mechanism regulating systemic immunity. In llp1 mutant plants, SAR was compromised, whereas the local resistance that is normally associated with EDS1 and SA as well as responses to exogenous SA appeared largely unaffected. Together, these data indicate that LLP1 promotes systemic rather than local immunity, possibly in parallel with SA. Our analysis reveals new positive and negative components of SAR and reinforces the notion that SAR represents a distinct phase of plant immunity beyond local resistance.

  6. Downhole water flow controller for aquifer storage recovery wells

    Energy Technology Data Exchange (ETDEWEB)

    Pyne, R.D.

    1987-09-08

    This patent describes a downhole flow control device for continuous automatic control of water flowing into or out of wells, aquifers and the like through pipe columns. The upper end of the first tubular member is mounted to the pipe column so as to be in fluid communication therewith. The lower end of the first tubular member is substantially closed. A second tubular member is mounted concentrically within and proximate to the first tubular member and has an open upper end and side walls and a substantially closed lower end. First openings are spaced in vertical relationship to the second openings. Third openings are through the second tubular member. The second tubular member is vertically movable with respect to the first tubular member so as to selectively align the third openings with either of the first and second openings. Biasing means are located between the lower ends of the first and second tubular members for normally urging the second tubular member vertically upward with respect to the first tubular member. The biasing means are yieldable upon the introduction of water into the pump column to permit the second tubular member to be vertically displaced relative to the first tubular member to thereby close the third openings with respect to the first or second openings. The third openings align with one of the first and second openings dependent upon the direction of fluid flow within the pipe column.

  7. Hydro-dynamic damping theory in flowing water

    Science.gov (United States)

    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.

  8. Field-scale water flow and solute transport : Swap model concepts, parameter estimation and case studies

    NARCIS (Netherlands)

    Dam, van J.C.

    2000-01-01

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

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

    Science.gov (United States)

    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%.

  10. Modelling of a water plasma flow: I. Basic results

    Energy Technology Data Exchange (ETDEWEB)

    KotalIk, Pavel [INP Greifswald, Friedrich-Ludwig-Jahn-Strasse 19, 17489 Greifswald (Germany)

    2006-06-21

    One-fluid MHD equations are numerically solved for an axisymmetric flow of thermal water plasma inside and outside a discharge chamber of a plasma torch with water vortex stabilization of electric arc. Comparisons with experimental data and previous calculations are given. For arc currents of 300-600 A, the respective temperatures and velocities in the range 16 700-26 400 K and 2300-6900 m s{sup -1} are obtained at the centre of the nozzle exit. The flow velocity on axis increases by 1-2 km s{sup -1} in the 5 mm long nozzle. Ohmic heating and radiative losses are two competitive processes influencing most the plasma temperature and velocity. The radiative losses represent 39% to 46% of the torch power of 69-174 kW when optical thickness of 3 mm is assumed for the plasma column. In front of the cathode, inside the discharge chamber, a recirculation zone is predicted and discussed. Effects of the temperature dependence of the plasma viscosity and sound velocity and of the optical thickness are examined. It is shown that the results such as waviness of the Mach number isolines are direct consequences of these dependences. Different lengths of 55 and 60 mm of the water vortex stabilized part of the electric arc do not substantially influence the plasma temperature and velocity at the nozzle exit.

  11. Experimental study of critical flow of water at supercritical pressure

    Institute of Scientific and Technical Information of China (English)

    Yuzhou CHEN; Chunsheng YANG; Shuming ZHANG; Minfu ZHAO; Kaiwen DU; Xu CHENG

    2009-01-01

    Experimental studies of the critical flow of water were conducted under steady-state conditions with a nozzle 1.41mm in diameter and 4.35 mm in length, covering the inlet pressure range of 22.1-26.8 MPa and inlet temperature range of 38^74°C. The parametric trend of the flow rate was investigated, and the experimental data were compared with the predictions of the homogeneous equilibrium model, the Bernoulli correlation, and the models used in the reactor safety analysis code RELAP5/ MOD3.3. It is concluded that in the near or beyond pseudo-critical region, thermal-dynamic equilibrium is dominant, and at a lower temperature, choking does not occur. The onset of the choking condition is not predicted reasonably by the RELAP5 code.

  12. Model grid and infiltration values for the transient ground-water flow model, Death Valley regional ground-water flow system, Nevada and California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This digital data set defines the model grid and infiltration values simulated in the transient ground-water flow model of the Death Valley regional ground-water...

  13. Discharge areas for the transient ground-water flow model, Death Valley regional ground-water flow system, Nevada and California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This digital data set represents discharge areas in the Death Valley regional ground-water flow system (DVRFS) transient model. Natural ground-water discharge occurs...

  14. Discharge areas for the transient ground-water flow model, Death Valley regional ground-water flow system, Nevada and California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This digital data set represents discharge areas in the Death Valley regional ground-water flow system (DVRFS) transient model. Natural ground-water discharge...

  15. An Experimental Study on the Flow Characteristics of OilWater Two-Phase Flow in Horizontal Straight Pipes

    Institute of Scientific and Technical Information of China (English)

    刘文红; 郭烈锦; 吴铁军; 张西民

    2003-01-01

    The flow patterns and their transitions of oil-water two-phase flow in horizontal pipes were studied. The experiments were conducted in two kinds of horizontal tubes, made of plexiglas pipe and stainless steel pipe with 40mm ID respectively. No. 46 mechanical oil and tap water were used as working fluids. The superficial velocity ranges of oil and water were: 0.04-1.2m·s-1 and 0.04-2.2 m·s-1, respectively. The flow patterns were identified by visualization and by transient fluctuation signals of differential pressure drop. The flow patterns were defined according to the relative distribution ofoil and water phases in the pipes. Flow pattern maps were obtained for both pipelines. In addition, semi-theoretical transition criteria for the flow patterns were proposed, and the proposed transitional criteria are in reasonable agreement with available data in liquid-liquid systems.

  16. Free jet water flow in Pelton turbines; Freistrahlstroemungen in Peltonturbinen

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Z.; Casey, M.

    2003-07-01

    This short article presents the results of experimental investigations made on the flow processes found in the jets of water in Pelton turbines. The results can be used to improve basic knowledge on the design of nozzles and the interaction between the jet and the cups on the Pelton turbine's wheel and thus help improve the efficiency of Pelton turbine systems. Brief details are given on the experimental arrangement and the measurement methods used, which included a Laser-Doppler-Anemometer system.

  17. THE HEAT AND FLUID FLOW ANALYSIS FOR WATER HEATER

    Directory of Open Access Journals (Sweden)

    Chien-Nan Lin

    2011-01-01

    Full Text Available In this paper, the heat transfer and fluid flow are studied for the water heater of RV cars, in which the hot water is heated by the combustion energy of liquefied petroleum gases. Three types of combustion tubes are performed in this investigation, which are circular tube, elliptic tube and elliptic tube with screwed wire inserted. The heat transfer performances of numerical simulation results are compared with those of the experimental works; they are in good trend agreement. The elliptic combustion tube performs better than the circular one, which indicates the average 7% energy saving for the elliptic combustion tube and 12% energy saving for the elliptic combustion tube with screwed wire under static heating.

  18. Flow boiling of water on nanocoated surfaces in a microchannel

    CERN Document Server

    Phan, Hai Trieu; Marty, Philippe; Colasson, Stéphane; Gavillet, Jérôme

    2010-01-01

    Experiments were performed to study the effects of surface wettability on flow boiling of water at atmospheric pressure. The test channel is a single rectangular channel 0.5 mm high, 5 mm wide and 180 mm long. The mass flux was set at 100 kg/m2 s and the base heat flux varied from 30 to 80 kW/m2. Water enters the test channel under subcooled conditions. The samples are silicone oxide (SiOx), titanium (Ti), diamond-like carbon (DLC) and carbon-doped silicon oxide (SiOC) surfaces with static contact angles of 26{\\deg}, 49{\\deg}, 63{\\deg} and 103{\\deg}, respectively. The results show significant impacts of surface wettability on heat transfer coefficient.

  19. Unsaturated water flow and tracer transport modeling with Alliances

    Energy Technology Data Exchange (ETDEWEB)

    Constantin, Alina, E-mail: alina.constantin@nuclear.ro [Institute for Nuclear Research, Campului Str, No. 1, PO Box 78, Postal Code 115400 Mioveni, Arges County (Romania); Genty, Alain, E-mail: alain.genty@cea.fr [CEA Saclay, DM2S/SFME/LSE, Gif-sur-Yvette 91191 cedex (France); Diaconu, Daniela; Bucur, Crina [Institute for Nuclear Research, Campului Str, No. 1, PO Box 78, Postal Code 115400 Mioveni, Arges County (Romania)

    2013-12-15

    Highlights: • Simulation of water flow and solute transport at Saligny site, Romania was done. • Computation was based on the available experimental data with Alliances platform. • Very good results were obtained for the saturation profile in steady state. • Close fit to experimental data for saturation profile at 3 m in transient state. • Large dispersivity coefficients were fitted to match tracer experiment. - Abstract: Understanding water flow and solute transport in porous media is of central importance in predicting the radionuclide fate in the geological environment, a topic of interest for the performance and safety assessment studies for nuclear waste disposal. However, it is not easy to predict transport properties in real systems because they are geologically heterogeneous from the pore scale upwards. This paper addresses the simulation of water flow and solute transport in the unsaturated zone of the Saligny site, the potential location for the Romanian low and intermediate level waste (LILW) disposal. Computation was based on the current available experimental data for this zone and was performed within Alliances, a software platform initially jointly developed by French organizations CEA, ANDRA and EDF. The output of the model developed was compared with the measured values in terms of saturation profile of the soil for water movement, in both steady and transient state. Very good results were obtained for the saturation profile in steady state and a close fit of the simulation over experimental data for the water saturation profile at a depth of 3 m in transient state. In order to obtain information regarding the solute migration in depth and the solute lateral dispersion, a tracer test was launched on site and dispersivity coefficients of the solute were fitted in order to match the experimental concentration determined on samples from different locations of the site. Results much close to the experiment were obtained for a longitudinal

  20. Re-evaluating the role of phenolic glycosides and ascorbic acid in ozone scavenging in the leaf apoplast of Arabidopsis thaliana L

    Science.gov (United States)

    To determine if membrane-bound G-proteins are involved in the regulation of defense responses against ozone in the leaf apoplast, the apoplastic concentrations of ascorbic acid and phenolic glycosides in Arabidopsis thaliana L. lines with null mutations in the alpha- and beta-subunits were compared ...

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

    Science.gov (United States)

    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.

  2. Water shortage risk assessment using spatiotemporal flow simulation

    Science.gov (United States)

    Hsieh, Hsin-I.; Su, Ming-Daw; Wu, Yii-Chen; Cheng, Ke-Sheng

    2016-12-01

    Paddy irrigation practices in Taiwan utilize complicated water conveyance networks which draw streamflows from different tributaries. Characterizing and simulating streamflow series is thus an essential task for irrigation risk assessment and planning mitigation measures. It generally involves modeling the temporal variation and spatial correlation of streamflow data at different sites. Like many other environmental variables, streamflows are asymmetric and non-Gaussian. Such properties exacerbate the difficulties in spatiotemporal modeling of streamflow data. A stochastic spatiotemporal simulation approach capable of generating non-Gaussian ten-day period streamflow data series at different sites is presented in this paper. Historical flow data from different flow stations in southern Taiwan were used to exemplify the application of the proposed model. Simulated realizations of the spatiotemporal anisotropic multivariate Pearson type III distribution were validated by comparing parameters and spatiotemporal correlation characteristics of the simulated data and the observed streamflow data. Risks of irrigation water shortage were estimated and the effect of mitigation measures was assessed using the simulated data.

  3. Flow and fracture in water-saturated, unconstrained granular beds

    Directory of Open Access Journals (Sweden)

    Germán eVaras

    2015-06-01

    Full Text Available The injection of gas in a liquid-saturated granular bed gives rise to a wide variety of invasion patterns. Many studies have focused on constrained porous media, in which the grains are fixed in the bed and only the interstitial fluid flows when the gas invades the system. With a free upper boundary, however, the grains can be entrained by the ascending gas or fluid motion, and the competition between the upward motion of grains and sedimentation leads to new patterns. We propose a brief review of the experimental investigation of the dynamics of air rising through a water-saturated, unconstrained granular bed, in both two and three dimensions. After describing the invasion pattern at short and long time, a tentative regime-diagram is proposed. We report original results showing a dependence of the fluidized zone shape, at long times, on the injection flow rate and grain size. A method based on image analysis makes it possible to detect not only the fluidized zone profile in the stationary regime, but also to follow the transient dynamics of its formation. Finally, we describe the degassing dynamics inside the fluidized zone, in the stationary regime. Depending on the experimental conditions, regular bubbling, continuous degassing, intermittent regime or even spontaneous flow-to-fracture transition are observed.

  4. Bridge Pressure Flow Scour at Clear Water Threshold Condition

    Institute of Scientific and Technical Information of China (English)

    GUO Junke; KERENYI Kornel; PAGAN-ORTIZ Jorge E; FLORA Kevin

    2009-01-01

    Bridge pressure flow scour at clear water threshold condition is studied theoretically and experimentally. The flume experiments reveal that the measured scour profiles under a bridge are more or less 2-dimensional; all the measured scour profiles can be described by two similarity equations, where the horizontal distance is scaled by the deck width while the local scour by the maximum scour depth; the maximum scour position is located just under the bridge about 15% deck width from the downstream deck edge; the scour begins at about one deck width upstream the bridge while the deposition occurs at about 2.5 deck widths downstream the bridge; and the maximum scour depth decreases with increas-ing sediment size, but increases with deck inundation. The theoretical analysis shows that: bridge scour can be divided into three cases, i.e. downstream unsubmerged, partially submerged, and totally submerged. For downstream unsubmerged flows, the maximum bridge scour depth is an open-channel problem where the conventional methods in terms of critical velocity or bed shear stress can be applied; for partially and totally submerged flows, the equilibrium maximum scour depth can be described by a scour and an inundation similarity number, which has been confirmed by experiments with two decks and two sediment sizes. For application, a design and field evaluation procedure with examples is presented, including the maximum scour depth and scour profile.

  5. Boundary of the ground-water flow model by IT Corporation (1996), for the Death Valley regional ground-water flow system study, Nevada and California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This digital data set defines the boundary of the steady-state ground-water flow model built by IT Corporation (1996). The regional, 20-layer ground-water flow model...

  6. Tangible Landscape: Cognitively Grasping the Flow of Water

    Science.gov (United States)

    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.

  7. Plant fluid proteomics: Delving into the xylem sap, phloem sap and apoplastic fluid proteomes.

    Science.gov (United States)

    Rodríguez-Celma, Jorge; Ceballos-Laita, Laura; Grusak, Michael A; Abadía, Javier; López-Millán, Ana-Flor

    2016-08-01

    The phloem sap, xylem sap and apoplastic fluid play key roles in long and short distance transport of signals and nutrients, and act as a barrier against local and systemic pathogen infection. Among other components, these plant fluids contain proteins which are likely to be important players in their functionalities. However, detailed information about their proteomes is only starting to arise due to the difficulties inherent to the collection methods. This review compiles the proteomic information available to date in these three plant fluids, and compares the proteomes obtained in different plant species in order to shed light into conserved functions in each plant fluid. Inter-species comparisons indicate that all these fluids contain the protein machinery for self-maintenance and defense, including proteins related to cell wall metabolism, pathogen defense, proteolysis, and redox response. These analyses also revealed that proteins may play more relevant roles in signaling in the phloem sap and apoplastic fluid than in the xylem sap. A comparison of the proteomes of the three fluids indicates that although functional categories are somewhat similar, proteins involved are likely to be fluid-specific, except for a small group of proteins present in the three fluids, which may have a universal role, especially in cell wall maintenance and defense. This article is part of a Special Issue entitled: Plant Proteomics--a bridge between fundamental processes and crop production, edited by Dr. Hans-Peter Mock.

  8. Purification and properties of apoplastic amylase from oat (Avena sativa) seedlings.

    Science.gov (United States)

    Uno-Okamura, Kuniko; Soga, Kouichi; Wakabayashi, Kazuyuki; Kamisaka, Seiichiro; Hoson, Takayuki

    2004-05-01

    The protein fraction extracted with a high ionic strength buffer from the cell wall preparation of oat (Avena sativa L.) coleoptiles and first leaves contained starch-degrading (amylase) activity. The activity of apoplastic amylase in the coleoptiles and first leaves continued to increase in parallel with organ growth. One of the apoplastic amylases recovered from shoot cell wall preparations was purified by sequential ion exchange and gel filtration chromatography, and the catalytic properties of the enzyme were analysed. The purified enzyme gave a single 25 kDa protein band on SDS-PAGE. The enzyme exhibited maximum activity at pH 5.0 against maltooligosaccharides. The purified enzyme hydrolysed soluble starch and maltooligosaccharides larger than tetraose at maltose unit, but did not hydrolyse beta-limit dextrin or p-nitrophenyl-alpha-d-glucopyranoside. These results as well as the findings that the molecular size and the catalytic properties of the purified enzyme are different from those of known amylases obtained from Gramineae caryopses suggest that this enzyme is a novel type of beta-amylase present in cell walls of vigorously elongating Gramineae shoot organs.

  9. Quantitative imaging of water flow in soil and roots using neutron radiography and deuterated water

    Energy Technology Data Exchange (ETDEWEB)

    Zarebanadkouki, Mohsen

    2013-05-08

    Where and how fast do roots take up water? Despite its importance in plant and soil sciences, there is limited experimental information on the location of water uptake along the roots of transpiring plants growing in soil. The answer to this question requires direct and in-situ measurement of the local flow of water into the roots. The aim of this study was to develop and apply a new method to quantify the local fluxes of water into different segments of the roots of intact plants. To this end, neutron radiography was used to trace the transport of deuterated water (D{sub 2}O) into the roots of lupines. Lupines were grown in aluminum containers filled with sandy soil. The soil was partitioned into different compartments using 1 cm-thick layers of coarse sand as capillary barriers. These barriers limited the diffusion of D{sub 2}O within the soil compartments. D{sub 2}O was locally injected into the selected soil compartments during the day (transpiring plants) and night (non-transpiring plants). Transport of D{sub 2}O into roots was then monitored by neutron radiography with spatial resolution of 100 μm and time intervals of 10 seconds. Neutron radiographs showed that: i) transport of D{sub 2}O into roots was faster during the day than during the night; 2) D{sub 2}O quickly moved along the roots towards the shoots during the day, while at night this axial transport was negligible. The differences between day and night measurements were explained by convective transport of D{sub 2}O into the roots. To quantify the net flow of water into roots, a simple convection-diffusion model was developed, where the increase rate of D{sub 2}O concentration in roots depended on the convective transport (net root water uptake) and the diffusion of D{sub 2}O into roots. The results showed that water uptake was not uniform along the roots. Water uptake was higher in the upper soil layers than in the deeper ones. Along an individual roots, the water uptake rate was higher in the

  10. An Investigation of the Water Flow Past the Butterfly Valve

    Science.gov (United States)

    Chaiworapuek, Weerachai; Champagne, Jean-Yves; El Haj em, Mahmoud; Kittichaikan, Chawalit

    2010-06-01

    This paper presents a numerical simulation of flow past the butterfly valve using Commercial Fluid Dynamics software FLUENT. In static analysis, the positions of the disk were set to be 0° (completely opened), 30°, 45°, 60° and 75° under 1, 2 and 3 m/s water speed. The angular velocities were set to be 0.039 and 1.57 rad/s under 1 m/s water speed in dynamic analysis. The study focuses on the investigation of the characteristic of loss coefficient and torque behavior of the 150 mm and 300 mm in diameter butterfly valves. From the results obtained, it was found that the loss coefficient and torque increased when the disk angle was increased. By increasing the water speed, the loss coefficient remained constant while the torque increased. In dynamic analysis of both angular speeds, the maximum torque occurred at 70°-80° in closing turn and 100°-110° in opening turn. The experiment was also carried out to verify the numerical results. By comparing between the experimental and numerical results, it was found that the loss coefficients and torques obtained from these methods were similar.

  11. FLOW PATTERN AND PRESSURE LOSS OF OIL-WATER TWO-PHASE FLOW IN HORIZONTAL STEEL PIPE

    Institute of Scientific and Technical Information of China (English)

    CHEN Jie; YAN Da-fan; ZHAO Jing-mei; AN Wei-jie; YAN Da-chun

    2005-01-01

    Experimental Study on oil-water two-phase flow patterns and pressure loss was conducted on a horizontal steel pipe loop with 26.1mm inner diameter and 30m total length.The working fluids are white oil, diesel oil and tap water.Several instruments, including a new type of liquid-probe are successfully integrated to identify 7 different flow patterns.The characteristics of the flow patterns and the transition process were observed and depicted in this paper.Investigation revealed that the pressure loss was mainly depended on the flow patterns.

  12. Water flows, energy demand, and market analysis of the informal water sector in Kisumu, Kenya.

    Science.gov (United States)

    Sima, Laura C; Kelner-Levine, Evan; Eckelman, Matthew J; McCarty, Kathleen M; Elimelech, Menachem

    2013-03-01

    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 m(3) per day) and delivered by hand-drawn water-carts (0.75 million m(3) 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/m(3)), 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.

  13. Documentation of the Santa Clara Valley regional ground-water/surface-water flow model, Santa Clara Valley, California

    Science.gov (United States)

    Hanson, R.T.; Li, Zhen; Faunt, C.C.

    2004-01-01

    The Santa Clara Valley is a long, narrow trough extending about 35 miles southeast from the southern end of San Francisco Bay where the regional alluvial-aquifer system has been a major source of water. Intensive agricultural and urban development throughout the 20th century and related ground-water development resulted in ground-water-level declines of more than 200 feet and land subsidence of as much as 12.7 feet between the early 1900s and the mid-1960s. Since the 1960s, Santa Clara Valley Water District has imported surface water to meet growing demands and reduce dependence on ground-water supplies. This importation of water has resulted in a sustained recovery of the ground-water flow system. To help support effective management of the ground-water resources, a regional ground-water/surface-water flow model was developed. This model simulates the flow of ground water and surface water, changes in ground-water storage, and related effects such as land subsidence. A numerical ground-water/surface-water flow model of the Santa Clara Valley subbasin of the Santa Clara Valley was developed as part of a cooperative investigation with the Santa Clara Valley Water District. The model better defines the geohydrologic framework of the regional flow system and better delineates the supply and demand components that affect the inflows to and outflows from the regional ground-water flow system. Development of the model includes revisions to the previous ground-water flow model that upgraded the temporal and spatial discretization, added source-specific inflows and outflows, simulated additional flow features such as land subsidence and multi-aquifer wellbore flow, and extended the period of simulation through September 1999. The transient-state model was calibrated to historical surface-water and ground-water data for the period 197099 and to historical subsidence for the period 198399. The regional ground-water flow system consists of multiple aquifers that are grouped

  14. Water circulation in non-isothermal droplet-laden turbulent channel flow

    NARCIS (Netherlands)

    Russo, E.; Kuerten, J.G.M.; Geld, van der C.W.M.; Geurts, B.J.; Simos, T.; Psihoyios, G.; Tsitouras, Ch.

    2013-01-01

    We propose a point-particle model for two-way coupling of water droplets dispersed in turbulent flow of a carrier gas consisting of air and water vapor. An incompressible flow formulation is applied for direct numerical simulation (DNS) of turbulent channel flow with a warm and a cold wall. Compared

  15. Water flow algorithm decision support tool for travelling salesman problem

    Science.gov (United States)

    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.

  16. FEWA: a Finite Element model of Water flow through Aquifers

    Energy Technology Data Exchange (ETDEWEB)

    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.

  17. Effects of virtual water flow on regional water resources stress: A case study of grain in China.

    Science.gov (United States)

    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.

  18. A penalization method for calculating the flow beneath travelling water waves of large amplitude

    CERN Document Server

    Constantin, Adrian; Scherzer, Otmar

    2014-01-01

    A penalization method for a suitable reformulation of the governing equations as a constrained optimization problem provides accurate numerical simulations for large-amplitude travelling water waves in irrotational flows and in flows with constant vorticity.

  19. Water temperature in irrigation return flow from the Upper Snake Rock watershed

    Science.gov (United States)

    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...

  20. Simulation of the Regional Ground-Water-Flow System and Ground-Water/Surface-Water Interaction in the Rock River Basin, Wisconsin

    Science.gov (United States)

    Juckem, Paul F.

    2009-01-01

    A regional, two-dimensional, areal ground-water-flow model was developed to simulate the ground-water-flow system and ground-water/surface-water interaction in the Rock River Basin. The model was developed by the U.S. Geological Survey (USGS), in cooperation with the Rock River Coalition. The objectives of the regional model were to improve understanding of the ground-water-flow system and to develop a tool suitable for evaluating the effects of potential regional water-management programs. The computer code GFLOW was used because of the ease with which the model can simulate ground-water/surface-water interactions, provide a framework for simulating regional ground-water-flow systems, and be refined in a stepwise fashion to incorporate new data and simulate ground-water-flow patterns at multiple scales. The ground-water-flow model described in this report simulates the major hydrogeologic features of the modeled area, including bedrock and surficial aquifers, ground-water/surface-water interactions, and ground-water withdrawals from high-capacity wells. The steady-state model treats the ground-water-flow system as a single layer with hydraulic conductivity and base elevation zones that reflect the distribution of lithologic groups above the Precambrian bedrock and a regionally significant confining unit, the Maquoketa Formation. In the eastern part of the Basin where the shale-rich Maquoketa Formation is present, deep ground-water flow in the sandstone aquifer below the Maquoketa Formation was not simulated directly, but flow into this aquifer was incorporated into the GFLOW model from previous work in southeastern Wisconsin. Recharge was constrained primarily by stream base-flow estimates and was applied uniformly within zones guided by regional infiltration estimates for soils. The model includes average ground-water withdrawals from 1997 to 2006 for municipal wells and from 1997 to 2005 for high-capacity irrigation, industrial, and commercial wells. In addition

  1. Visualization of water flow during filtration using flat filtration materials

    Directory of Open Access Journals (Sweden)

    Hrůza Jakub

    2012-04-01

    Full Text Available Filtration materials are very important elements of some industrial appliances. Water filtration is a separation of solid materials from fluid. Solid particles are captured on the frontal area of the filtration textile and only liquid passes through it. It is important to know the filtration process in a detailed way to be able to develop filtration materials. Visualization of filtration process enables a better view of the filtration. This method also enables to determine efficiency and homogeneity of filtration using image analysis. For this purpose, a new waterfiltration measuring setup was proposed and constructed. Filtration material is mounted into the optically transparent place in the setup. Laser sheet is directed into this place as in the case of Particle Image Velocimetry measuring method. Monochrome and sensitive camera records the light scattered by seeding particles in water. The seeding particles passing through the filter serve for measuring filtration efficiency, and also for visualization of filtration process. Filtration setup enables to measure also the pressure drop and a flow. The signals are processed by National Instruments compactDAQ system and UMA software. Microfibrous and nanofibrous filtration materials are tested by this measuring method. In the case of nanofibrous filtration, appropriate size of seeding particles is needed to be used to perform a process of filtration.

  2. Patterns of a slow air-water flow in a semispherical container

    DEFF Research Database (Denmark)

    Balci, Adnan; Brøns, Morten; Herrada, Miguel A.

    2016-01-01

    This numerical study analyzes the development of eddies in a slow steady axisymmetric air-water flow in a sealed semispherical container, driven by a rotating top disk. As the water height, Hw, increases, new flow cells emerge in both water and air. First, an eddy emerges near the axis-bottom int......This numerical study analyzes the development of eddies in a slow steady axisymmetric air-water flow in a sealed semispherical container, driven by a rotating top disk. As the water height, Hw, increases, new flow cells emerge in both water and air. First, an eddy emerges near the axis...... on the air flow. In contrast to flows in cylindrical and conical containers, there is no interaction with Moffatt corner vortices here....

  3. Analytical Model of Water Flow in Coal with Active Matrix

    Science.gov (United States)

    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

  4. Calibration of Mineralization Degree for Dynamic Pure-water Measurement in Horizontal Oil-water Two-phase Flow

    Science.gov (United States)

    Kong, Weihang; Li, Lei; Kong, Lingfu; Liu, Xingbin

    2016-08-01

    In order to solve the problem of dynamic pure-water electrical conductivity measurement in the process of calculating water content of oil-water two-phase flow of production profile logging in horizontal wells, a six-group local-conductance probe (SGLCP) is proposed to measure dynamic pure-water electrical conductivity in horizontal oil-water two-phase flow. The structures of conductance sensors which include the SGLCP and ring-shaped conductance probe (RSCP) are analyzed by using the finite-element method (FEM). In the process of simulation, the electric field distribution generated by the SGLCP and RSCP are investigated, and the responses of the measuring electrodes are calculated under the different values of the water resistivity. The static experiments of the SGLCP and RSCP under different mineralization degrees in horizontal oil-water two-phase flow are carried out. Results of simulation and experiments demonstrate a nice linearity between the SGLCP and RSCP under different mineralization degrees. The SGLCP has also a good adaptability to stratified flow, stratified flow with mixing at the interface and dispersion of oil in water and water flow. The validity and feasibility of pure-water electrical conductivity measurement with the designed SGLCP under different mineralization degrees are verified by experimental results.

  5. Water hammer in coarse-grained solid-liquid flows in hydraulic hoisting for ocean mining

    Institute of Scientific and Technical Information of China (English)

    韩文亮; 王光谦; 吴保生; 刘少军; 邹伟生

    2002-01-01

    The particles of polymetallic nodules in hydraulic hoisting flows that are used for mining in deep sea are rather coarse, therefore their flow velocity is smaller than that of the surrounding water. The characteristics of solid-liquid flows such as their density, concentration, elastic modulus and resistance were discussed. The wave propagation speed and the continuity and momentum equations of water hammer in coarse-grained solid-liquid flows were theoretically derived, and a water hammer model for such flows was developed.

  6. Non-linear effects on solute transfer between flowing water and a sediment bed.

    Science.gov (United States)

    Higashino, Makoto; Stefan, Heinz G

    2011-11-15

    A previously developed model of periodic pore water flow in space and time, and associated solute transport in a stream bed of fine sand is extended to coarse sand and fine gravel. The pore water flow immediately below the sediment/water interface becomes intermittently a non-Darcy flow. The periodic pressure and velocity fluctuations considered are induced by near-bed coherent turbulent motions in the stream flow; they penetrate from the sediment/water interface into the sediment pore system and are described by a wave number (χ) and a period (T) that are given as functions of the shear velocity (U(∗)) between the flowing water and the sediment bed. The stream bed has a flat surface without bed forms. The flow field in the sediment pore system is described by the continuity equation and a resistance law that includes both viscous (Darcy) and non-linear (inertial) effects. Simulation results show that non-linear (inertial) effects near the sediment/water interface increase flow resistance and reduce mean flow velocities. Compared to pure Darcy flow, non-linear (inertial) effects reduce solute exchange rates between overlying water and the sediment bed but only by a moderate amount (less than 50%). Turbulent coherent flow structures in the stream flow enhance solute transfer in the pore system of a stream bed compared to pure molecular diffusion, but by much less than standing surface waves or bed forms.

  7. Localization of acid phosphatase activity in the apoplast of root nodules of pea (Pisum sativum

    Directory of Open Access Journals (Sweden)

    Marzena Sujkowska

    2011-01-01

    Full Text Available Changes in the activity of acid phosphatase (AcPase in the apoplast of pea root nodule were investigated. The activity was determined using lead and cerium methods. The results indicated a following sequence of AcPase activity appearance during the development of the infection thread: 1 low AcPase activity appears in the outer part of cells of symbiotic bacteria; 2 bacteria show increased AcPase activity, and the enzyme activity appears in the thread walls; 3 activity exhibits also matrix of the infection thread; 4 bacteria just before their release from the infection threads show high AcPase activity; 5 AcPase activity ceases after bacteria transformation into bacteroids. The increase in bacterial AcPase activity may reflect a higher demand for inorganic phosphorus necessary for propagation of the bacteria within the infection threads and/or involved in bacteria release from the infection threads.

  8. The Design of Impact Test-Bed for High-Flow Water Medium Relief Valve

    Directory of Open Access Journals (Sweden)

    Junliang Chang

    2014-11-01

    Full Text Available Water medium hydraulic systems are widely used in coal mining machinery. As the power of hydraulic system becomes higher, the flow and pressure of water medium relief valve are also higher, and the flow may reach 2000 L/min. However, there is no relevant test-bed which could provide instantaneous high-pressure and high-flow to support the experiment for high-flow relief valve; consequently, this impact test-bed for high-flow water medium relief valve is designed to satisfy fast loading demand. Through building model, simulation analysis, and construction of an impact test-bed of high-flow water medium relief valve, the dynamic performance of high-flow water medium relief valve is detected. The setting pressure of relief valve, the accumulator volume and the filling fluid pressure, and the damping of cartridge valve can be changed, and the dynamic performance of high-flow water medium relief valve under different impact loads is detected. The results show that the designed impact test-bed of high-flow water medium relief valve could provide required high-pressure and high-flow emulsion for the tested water medium relief valve, and it could control the strength of impact load, which is an energy saving, high efficiency, and low cost method.

  9. Logging Effects on Streamflow: Water Yield and Summer Low Flows at Caspar Creek in Northwestern California

    Science.gov (United States)

    Keppeler, Elizabeth T.; Ziemer, Robert R.

    1990-07-01

    Streamflow data for a 21-year period were analyzed to determine the effects of selective tractor harvesting of second-growth Douglas fir and redwood forest on the volume, timing, and duration of low flows and annual water yield in northwestern California. The flow response to logging was highly variable. Some of this variability was correlated with antecedent precipitation conditions. Statistically significant increases in streamflow were detected for both the annual period and the low-flow season. Relative increases in water yield were greater for the summer low-flow period than for annual flows, but these summer flow increases generally disappeared within 5 years.

  10. Pectins esterification in the apoplast of aluminum-treated pea root nodules.

    Science.gov (United States)

    Sujkowska-Rybkowska, Marzena; Borucki, Wojciech

    2015-07-20

    Aiming to elucidate the possible involvement of pectins in aluminum-mediated growth inhibition the distribution of pectins in the apoplast of root nodules was investigated. Experiments were performed on the pea (Pisum sativum L.) root nodules treated with aluminum (50 μM AlCl3, for 2 or 24h). For histochemical acidic pectin localization we used ruthenium red staining. Immunolabeling techniques with monoclonal antibodies specific to high methyl-esterified pectin (JIM7), low methyl-esterified pectin (JIM5) and calcium cross-linked pectin (2F4) were used to re-examine the pattern of pectin esterification and distribution. After immunolabeling the samples were observed using a fluorescent and transmission electron microscope. Ruthenium red staining showed that acid pectin content increased in the apoplast of Al-treated nodules and immunolocalization of pectin epitopes revealed that the fraction of de-esterified pectins increased significantly under Al stress. JIM5 and 2F4 epitopes were located on the inner surface of the primary cell wall with higher intensity at cell corners lining the intercellular spaces and at infection threads (ITs) walls. By contrast, JIM 7 labels all walls uniformly throughout the nodule. In the presence of Al, the increase of JIM5 and 2F4 labeling in thick plant and IT walls, together with a decrease of JIM7 labeling was observed. These results indicate a specific role for pectin de-esterification in the process of wall thickening and growth inhibition. In particular, Al-dependent increase in pectin content and their low methyl esterification degree correlate with wall thickness and higher rigidity, and in this way, may affect IT and nodules growth.

  11. Pore Water Pressure Contribution to Debris Flow Mobility

    OpenAIRE

    Chiara Deangeli

    2009-01-01

    Problem statement: Debris flows are very to extremely rapid flows of saturated granular soils. Two main types of debris flow are generally recognized: Open slope debris flows and channelized debris flows. The former is the results of some form of slope failures, the latter can develop along preexisting stream courses by the mobilization of previously deposited debris blanket. The problem to be addressed is the influence of the mode of initiation on the subsequent mechanism of propagation. In ...

  12. Ultrasonic method for measuring water holdup of low velocity and high-water-cut oil-water two-phase flow

    Science.gov (United States)

    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.

  13. Computational theory of cavitating flows for hydraulic turbomachinery with consideration of influence of water quality

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Previously it was assumed that the pressure within the cavity or on the cavity surface remained constant and the vapor pressure of clean water at 20°C and 0 m altitude was utilized as the computational boundary for cavitating flows in hydraulic turbomachinery. Cavitation was confused with vaporization, and the effect of water quality on cavitation pressure characteristics was not taken into account. In recent years, lots of experiments of cavitation pressure characteristics of different water qualities including different sand concentrations of sand water and different altitudes of clean water have been performed by the authors, and the important influences of water quality on cavitation pressure characteristic have been validated. Thus the water quality should be involved in the cavitating flows computation. In the present paper, the effect of water quality on the cavitation pressure characteristic is analyzed and the computational method and theory of cavitating flows for hydraulic turbomachinery that considers the influence of water quality are proposed. The theory is suitable for both the potential flow method and the two-phase flow method for cavitating flows simulation. Finally, the validation results for cavitating flows in a hydraulic tur- bine indicate the significant influences of water quality on the cavitating flow performance.

  14. Simulation of water flows in multiple columns with small outlets

    Energy Technology Data Exchange (ETDEWEB)

    Suh, Yong Kweon; Li, Zi Lu; Jeong, Jong Hyun; Lee, Jun Hee [Dong-A University, Busan (Korea, Republic of)

    2006-10-15

    High-pressure die casting such as thixocasting and rheocasting is an effective process in the manufacturing automotive parts. Following the recent trend in the automotive manufacturing technologies, the product design subject to the die casting becomes more and more complex. Simultaneously the injection speed is also designed to be very high to establish a short cycle-time. Thus, the requirement of the die design becomes more demanding than ever before. In some cases the product's shape can have multiple slender manifolds. In such cases, design of the inlet and outlet parts of the die is very important in the whole manufacturing process. The main issues required for the qualified products are to attain gentle and uniform flow of the molten liquid within the passages of the die. To satisfy such issues, the inlet cylinder ('bed cylinder' in this paper) must be as large as possible and simultaneously the outlet opening at the end of each passage must be as small as possible. However these in turn obviously bring additional manufacturing costs caused by re-melting of the bed cylinder and increased power due to the small outlet-openings. The purpose of this paper is to develop effective simulation methods of calculation for fluid flows in multiple columns, which mimic the actual complex design, and to get some useful information which can give some contributions to the die-casting industry. We have used a commercial code CFX in the numerical simulation. The primary parameter involved is the size of the bed cylinder. We will show how the very small opening of the outlet can be treated with the aid of the porous model provided in the code. To check the validity of the numerical results we have also conducted a simple experiment by using water.

  15. Lateral boundary of the transient ground-water flow model, Death Valley regional ground-water flow system, Nevada and California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This digital data set defines the lateral boundary and model domain of the area simulated by the transient ground-water flow model of the Death Valley regional...

  16. Initial hydraulic heads for the transient ground-water flow model, Death Valley regional ground-water flow system, Nevada and California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This digital data set defines the hydraulic-head values in 16 model layers used to initiate the transient simulation of the Death Valley regional ground-water flow...

  17. Influences of friction drag on spontaneous condensation in water vapor supersonic flows

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    A mathematical model was developed to investigate the water vapor spontaneous condensation under supersonic flow conditions. A numerical simulation was performed for the water vapor condensable supersonic flows through Laval nozzles under different flow friction conditions. The comparison between numerical and experimental results shows that the model is accurate enough to investigate the supersonic spontaneous condensation flow of water vapor inside Laval nozzles. The influences of flow friction drag on supersonic spontaneous condensation flow of water vapor inside Laval nozzles were investigated. It was found that the flow friction has a direct effect on the spontaneous condensation process and therefore it is important for an accurate friction prediction in designing this kind of Laval nozzles.

  18. Influences of friction drag on spontaneous condensation in water vapor supersonic flows

    Institute of Scientific and Technical Information of China (English)

    JIANG WenMing; LIU ZhongLiang; LIU HengWei; PANG HuiZhong; BAO LingLing

    2009-01-01

    A mathematical model was developed to investigate the water vapor spontaneous condensation under supersonic flow conditions. A numerical simulation was performed for the water vapor condensable supersonic flows through Laval nozzles under different flow friction conditions. The comparison be-tween numerical and experimental results shows that the model is accurate enough to investigate the supersonic spontaneous condensation flow of water vapor inside Laval nozzles. The influences of flow friction drag on supersonic spontaneous condensation flow of water vapor inside Laval nozzles were investigated, It was found that the flow friction has a direct effect on the spontaneous condensation process and therefore it is important for an accurate friction prediction in designing this kind of Laval nozzles.

  19. Construction of estimated flow- and load-duration curves for Kentucky using the Water Availability Tool for Environmental Resources (WATER)

    Science.gov (United States)

    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.

  20. A MODEL FOR PREDICTING PHASE INVERSION IN OIL-WATER TWO-PHASE PIPE FLOW

    Institute of Scientific and Technical Information of China (English)

    GONG Jing; LI Qing-ping; YAO Hai-yuan; YU Da

    2006-01-01

    Experiments of phase inversion characteristics for horizontal oil-water two-phase flow in a stainless steel pipe loop (25.7 mm inner diameter,52 m long) are conducted. A new viewpoint is brought forward about the process of phase inversion in oil-water two-phase pipe flow. Using the relations between the total free energies of the pre-inversion and post-inversion dispersions, a model for predicting phase inversion in oil-water two-phase pipe flow has been developed that considers the characteristics of pipe flow. This model is compared against other models with relevant data of phase inversion in oil-water two-phase pipe flow. Results indicate that this model is better than other models in terms of calculation precision and applicability. The model is useful for guiding the design for optimal performance and safety in the operation of oil-water two-phase pipe flow in oil fields.

  1. Approximate solutions for Forchheimer flow during water injection and water production in an unconfined aquifer

    Science.gov (United States)

    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.

  2. Assessing microbiological water quality in drinking water distribution systems with disinfectant residual using flow cytometry.

    Science.gov (United States)

    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.

  3. Volumetric flow rate comparisons for water and product on pasteurization systems.

    Science.gov (United States)

    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.

  4. Water behavior in a u-shaped flow channel of PEM fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Quan, P.; Zhou, B.; Sobiesiak, A. [Windsor Univ., ON (Canada). Dept. of Mechanical, Automotive and Materials Engineering; Liu, Z.S. [National Research Council of Canada, Vancouver, BC (Canada). Inst. for Fuel Cell Innovation

    2005-07-01

    A study was conducted to find a practical approach for predicting liquid water distribution in the U-shaped flow channels of a proton exchange membrane (PEM) fuel cell. Computational fluid dynamics modeling with the FLUENT software package was used to demonstrate the two-phase flow of the air-water transport process inside the channel. It was noted that no chemical reaction occurs inside the flow channels and the liquid water is formed either on the surfaces of the flow channels or inside the flow channels. The problem can therefore be simplified as a fluid mechanics problem with water sources inside its physical domain or on its boundaries. The volume-of-fluid (VOF) model was used to track dynamic air-water interactions. Three cases with a range of initial water phase distributions corresponding to different fuel cell operating conditions were simulated numerically to gain a better understanding of water behaviour inside the serpentine channel. It was concluded that the bend area in the serpentine flow field affects the fuel cell performance. This is because it influences the flow field which in turn influences the air-water flow and water liquid distribution inside the channel or along the inside channel surfaces. 15 refs., 1 tab., 11 figs.

  5. Source Water Flow Pathways In Forested, Mountain, Headwater Streams: A Link Between Sediment Movement Patterns And Stream Water Chemistry.

    Science.gov (United States)

    Martin, S.; Conklin, M. H.; Liu, F.

    2015-12-01

    Three years of continuous and discrete sediment and water quality data, from four forested, mountain, headwater catchments in the Sierra Nevada, is used to identify water sources, determine the importance of sub-surface flow pathways, detect any changes in source waters due to seasonal variation or drought, and link flow pathways with observed patterns of in-channel sediment movement within the study watersheds. Patterns in stream chemistry and turbidity point to infiltration as the dominant flow pathway within these catchments. Data support a flow pathway conceptual model in which precipitation water infiltrates into the shallow or deeper subsurface, increasing the hydraulic head of the water table and pushing pre-event water into the stream ahead of event water. Study catchments contain perennial streams and are characterized by a Mediterranean climate with a distinct wet and dry season. Sites are located in the rain-snow transition zone with snow making up 40 to 60 percent of average annual precipitation. Barring human disturbances such as logging/grazing (compaction) or fire (hydrophobicity), catchment soils have high infiltration capacities. Springs and seeps maintain baseflow during the summer low-flow season, and shifting chemical signals within the streams indicate the increased importance of sub-surface water sources during drought years. End-member mixing analysis was conducted to identify possible water end members. Turbidity hysteresis patterns described by previous studies show in-channel sources are dominant for discharge events year round, and there is no difference in fine sediment delivery to streams with or without a soil protecting layer of snow on the land surface. The dominance of sub-surface water sources and evidence for infiltration flow fits with turbidity data, as little material is reaching the stream due to erosive overland flow. An understanding of flow pathways provides a foundation for sustainable land use management in forested

  6. Protein profile of Beta vulgaris leaf apoplastic fluid and changes induced by Fe deficiency and Fe resupply

    Directory of Open Access Journals (Sweden)

    Laura eCeballos-Laita

    2015-03-01

    Full Text Available The fluid collected by direct leaf centrifugation has been used to study the proteome of the sugar beet apoplastic fluid as well as the changes induced by Fe deficiency and Fe resupply to Fe-deficient plants in the protein profile. Plants were grown in Fe-sufficient and Fe-deficient conditions, and Fe resupply was carried out with 45 μM Fe(III-EDTA for 24 h. Protein extracts of leaf apoplastic fluid were analyzed by two-dimensional isoelectric focusing-SDS-PAGE electrophoresis. Gel image analysis revealed 203 consistent spots, and proteins in 81% of them (164 were identified by nLC-MS/MS using a custom made reference repository of beet protein sequences. When redundant UniProt entries were deleted, a non-redundant leaf apoplastic proteome consisting of 109 proteins was obtained. TargetP and SecretomeP algorithms predicted that 63% of them were secretory proteins. Functional classification of the non-redundant proteins indicated that stress and defense, protein metabolism, cell wall and C metabolism accounted for approximately 75% of the identified proteome. The effects of Fe-deficiency on the leaf apoplast proteome were limited, with only five spots (2.5% changing in relative abundance, thus suggesting that protein homeostasis in the leaf apoplast fluid is well maintained upon Fe shortage. The identification of three chitinase isoforms among proteins increasing in relative abundance with Fe-deficiency suggests that one of the few effects of Fe deficiency in the leaf apoplast proteome includes cell wall modifications. Iron resupply to Fe deficient plants changed the relative abundance of 16 spots when compared to either Fe-sufficient or Fe-deficient samples. Proteins identified in these spots can be broadly classified as those responding to Fe-resupply, which included defense and cell wall related proteins, and non-responsive, which are mainly protein metabolism related proteins and whose changes in relative abundance followed the same trend as

  7. Centrifugal Modelling of Transient Water Flow in Earth Embankments.

    Science.gov (United States)

    1980-05-07

    Redshaw [10] in their recent book and the transient flow net technique described by Cedergren Approximate Solutions The solution of the transient flow...and Foundation Engineering, Paris, Vol. II, pp. 551-554. 3. Cedergren , H.R., Seepage, Drainage, and Flow Nets, 2nd Ed., New York, John Wiley & Sons

  8. Movement of coliform bacteria and nutrients in ground water flowing through basalt and sand aquifers.

    Science.gov (United States)

    Entry, J A; Farmer, N

    2001-01-01

    Large-scale deposition of animal manure can result in contamination of surface and ground water and in potential transfer of disease-causing enteric bacteria to animals or humans. We measured total coliform bacteria (TC), fecal coliform bacteria (FC), NO3, NH4, total P, and PO4 in ground water flowing from basalt and sand aquifers, in wells into basalt and sand aquifers, in irrigation water, and in river water. Samples were collected monthly for 1 yr. Total coliform and FC numbers were always higher in irrigation water than in ground water, indicating that soil and sediment filtered most of these bacteria before they entered the aquifers. Total coliform and FC numbers in ground water were generally higher in the faster flowing basalt aquifer than in the sand aquifer, indicating that the slower flow and finer grain size may filter more TC and FC bacteria from water. At least one coliform bacterium/100 mL of water was found in ground water from both basalt and sand aquifers, indicating that ground water pumped from these aquifers is not necessarily safe for human consumption according to the American Public Health Association and the USEPA. The NO3 concentrations were usually higher in water flowing from the sand aquifer than in water flowing from the basalt aquifer or in perched water tables in the basalt aquifer. The PO4 concentrations were usually higher in water flowing from the basalt aquifer than in water flowing from the sand aquifer. The main concern is fecal contamination of these aquifers and health consequences that may arise from human consumption.

  9. Oxygen consumption by a sediment bed for stagnant water: comparison to SOD with fluid flow.

    Science.gov (United States)

    Higashino, Makoto

    2011-10-01

    A model of sedimentary oxygen demand (SOD) for stagnant water in a lake or a reservoir is presented. For the purposes of this paper, stagnant water is defined as the bottom layer of stratified water columns in relatively unproductive systems that are underlain by silt and sand-dominated sediments with low-organic carbon (C) and nitrogen (N). The modeling results are compared to those with fluid flow to investigate how flow over the sediment surface raises SOD compared to stagnant water, depending on flow velocity and biochemical activity in the sediment. SOD is found to be substantially limited by oxygen transfer in the water column when water is stagnant. When flow over the sediment surface is present, SOD becomes larger than that for stagnant water, depending on flow velocity and the biochemical oxygen uptake rate in the sediment. Flow over the sediment surface causes an insignificant raise in SOD when the biochemical oxygen uptake rate is small. The difference between SOD with fluid flow and SOD for stagnant water becomes significant as the biochemical oxygen uptake rate becomes larger, i.e. SOD is 10-100 times larger when flow over the sediment surface is present.

  10. A Device to Emulate Diffusion and Thermal Conductivity Using Water Flow

    Science.gov (United States)

    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.

  11. Basal interstitial water pressure in laboratory debris flows over a rigid bed in an open channel

    Directory of Open Access Journals (Sweden)

    N. Hotta

    2012-08-01

    Full Text Available Measuring the interstitial water pressure of debris flows under various conditions gives essential information on the flow stress structure. This study measured the basal interstitial water pressure during debris flow routing experiments in a laboratory flume. Because a sensitive pressure gauge is required to measure the interstitial water pressure in shallow laboratory debris flows, a differential gas pressure gauge with an attached diaphragm was used. Although this system required calibration before and after each experiment, it showed a linear behavior and a sufficiently high temporal resolution for measuring the interstitial water pressure of debris flows. The values of the interstitial water pressure were low. However, an excess of pressure beyond the hydrostatic pressure was observed with increasing sediment particle size. The measured excess pressure corresponded to the theoretical excess interstitial water pressure, derived as a Reynolds stress in the interstitial water of boulder debris flows. Turbulence was thought to induce a strong shear in the interstitial space of sediment particles. The interstitial water pressure in boulder debris flows should be affected by the fine sediment concentration and the phase transition from laminar to turbulent debris flow; this should be the subject of future studies.

  12. Bifurcations of a creeping air–water flow in a conical container

    DEFF Research Database (Denmark)

    Balci, Adnan; Brøns, Morten; Herrada, Miguel A.

    2016-01-01

    This numerical study describes the eddy emergence and transformations in a slow steady axisymmetric air–water flow, driven by a rotating top disk in a vertical conical container. As water height (Formula presented.) and cone half-angle (Formula presented.) vary, numerous flow metamorphoses occur...

  13. Computing equations of water hammer in pseudo-homogeneous solid-liquid flow and their verification

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In engineering practice, single-phase water hammer models are still employed to analyze the water hammer of solid-liquid flow. According to the characteristics of solid-liquid flow, continuity equations and momentum equations of pseudo-homogeneous flows are deduced, and a pseudo-homogeneous water hammer model is thus built and verified with experiment results. The characteristics of solid-liquid flow's viscosity, resistance and wave velocity are considered in the model. Therefore, it has higher precision than a single-phase model.

  14. Synthesis of niobium pentoxide nanoparticles in single-flow supercritical water

    Science.gov (United States)

    Fuchigami, Teruaki; Kakimoto, Ken-ichi

    2016-10-01

    The development of a new synthesis method is still required for very fine oxide nanoparticles. In this study, a single-flow supercritical fluid system has been developed for the synthesis of highly crystalline nanosized oxide particles. Niobium oxide particles were synthesized by single-flow supercritical water treatment, batch-type supercritical water treatment and subcritical water treatment. Niobium pentoxide nanoparticles synthesized by single-flow supercritical water treatment at 673 K, 24.5 MPa, and 15 ml min-1 flow rate had a pseudohexagonal structure. The morphology of the nanoparticle was a rod, and it has a smaller particle size and larger crystallite size than those of the oxide particles synthesized by the other methods, because the particle growth and the decomposition of surfactant were rapidly suppressed in the single-flow supercritical water treatment. The nanosized niobium pentoxide is useful as a catalyst in harsh environments and as a precursor powder of lead-free piezoelectric materials.

  15. A water balance model to estimate flow through the Old and Middle River corridor

    Science.gov (United States)

    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.

  16. Effects of anthropogenic water regulation and groundwater lateral flow on land processes

    Science.gov (United States)

    Zeng, Yujin; Xie, Zhenghui; Yu, Yan; Liu, Shuang; Wang, Linying; Zou, Jing; Qin, Peihua; Jia, Binghao

    2016-09-01

    Both anthropogenic water regulation and groundwater lateral flow essentially affect groundwater table patterns. Their relationship is close because lateral flow recharges the groundwater depletion cone, which is induced by over-exploitation. In this study, schemes describing groundwater lateral flow and human water regulation were developed and incorporated into the Community Land Model 4.5. To investigate the effects of human water regulation and groundwater lateral flow on land processes as well as the relationship between the two processes, three simulations using the model were conducted for the years 2003-2013 over the Heihe River Basin in northwestern China. Simulations showed that groundwater lateral flow driven by changes in water heads can essentially change the groundwater table pattern with the deeper water table appearing in the hillslope regions and shallower water table appearing in valley bottom regions and plains. Over the last decade, anthropogenic groundwater exploitation deepened the water table by approximately 2 m in the middle reaches of the Heihe River Basin and rapidly reduced the terrestrial water storage, while irrigation increased soil moisture by approximately 0.1 m3 m-3. The water stored in the mainstream of the Heihe River was also reduced by human surface water withdrawal. The latent heat flux was increased by 30 W m-2 over the irrigated region, with an identical decrease in sensible heat flux. The simulated groundwater lateral flow was shown to effectively recharge the groundwater depletion cone caused by over-exploitation. The offset rate is higher in plains than mountainous regions.

  17. Water Management for Competing Uses: Environmental Flows in the Transboundary Rio Grande/Rio Bravo

    Science.gov (United States)

    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

  18. Involvement of nitrogen functional groups in high-affinity copper binding in tomato and wheat root apoplasts: spectroscopic and thermodynamic evidence.

    Science.gov (United States)

    Guigues, Stéphanie; Bravin, Matthieu N; Garnier, Cédric; Masion, Armand; Chevassus-Rosset, Claire; Cazevieille, Patrick; Doelsch, Emmanuel

    2016-03-01

    Carboxylic groups located in plant cell walls (CW) are generally considered to be the main copper binding sites in plant roots, despite the presence of other functional groups. The aim of this study was to investigate sites responsible for copper binding in root apoplasts, i.e. CW and outer surface of the plasma membrane (PM) continuum. Binding sites in root apoplasts were investigated by comparing isolated CW of a monocotyledon (Triticum aestivum L.) and dicotyledon (Solanum lycopersicum L.) crop with their respective whole roots. Copper speciation was examined by X-ray absorption (XAS) and (13)C-nuclear magnetic resonance spectroscopies while the affinity of ligands involved in copper binding was investigated by modeling copper sorption isotherms. Homogeneous speciation and binding of copper was found in wheat and tomato root apoplasts. Only Cu-N and Cu-O bonds were detected in wheat and tomato root apoplasts. Nitrogen/oxygen ligands were identified in slightly higher proportions (40-70%) than single oxygen ligands. Furthermore, low- and high-affinity binding sites contributed in an almost equivalent proportion to copper binding in root apoplasts. The high-affinity N functional groups embedded in root apoplasts participated in copper binding in the same magnitude than the low-affinity carboxylic groups.

  19. Linking water quality and quantity in environmental flow assessment in deteriorated ecosystems: a food web view.

    Science.gov (United States)

    Chen, He; Ma, Lekuan; Guo, Wei; Yang, Ying; Guo, Tong; Feng, Cheng

    2013-01-01

    Most rivers worldwide are highly regulated by anthropogenic activities through flow regulation and water pollution. Environmental flow regulation is used to reduce the effects of anthropogenic activities on aquatic ecosystems. Formulating flow alteration-ecological response relationships is a key factor in environmental flow assessment. Traditional environmental flow models are characterized by natural relationships between flow regimes and ecosystem factors. However, food webs are often altered from natural states, which disturb environmental flow assessment in such ecosystems. In ecosystems deteriorated by heavy anthropogenic activities, the effects of environmental flow regulation on species are difficult to assess with current modeling approaches. Environmental flow management compels the development of tools that link flow regimes and food webs in an ecosystem. Food web approaches are more suitable for the task because they are more adaptive for disordered multiple species in a food web deteriorated by anthropogenic activities. This paper presents a global method of environmental flow assessment in deteriorated aquatic ecosystems. Linkages between flow regimes and food web dynamics are modeled by incorporating multiple species into an ecosystem to explore ecosystem-based environmental flow management. The approach allows scientists and water resources managers to analyze environmental flows in deteriorated ecosystems in an ecosystem-based way.

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

    Science.gov (United States)

    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 environmental conditions, which if not actively control, lead to sustainable experimental noise and drift. Consequently, our continuous-flow water sample employs active control for all pertinent parameters, significantly increasing its stability and usability. We will present data from controlled laboratory experiments demonstrating sample-to-sample precision and long-term stability. We will also show experimental data that highlights the instrumental sample-to-sample memory, which we have decreased significantly from previous implementations of this technology. Additionally, we will present field results from the Sacramento River, CA. Dansgaard, W. (1964) 'Stable isotopes in precipitation', Tellus, 16(4), p. 436-468. Munksgaard, N.C., Wurster, C.M., Bass, A., Zagorskis, I., and Bird, M.I. (2012) 'First continuous shipboard d18O and dD measurements in seawater by diffusion sampling--cavity ring-down spectrometry', Environmental Chemistry Letters, 10, p.301-307. Munksgaard, N.C., Wurster, C.M., and Bird, M.I., (2011), 'Continuous analysis of δ18O and δD values of water by diffusion sampling cavity ring-down spectrometry: a novel sampling device for unattended field monitoring of precipitation, ground and surface waters', Rapid Communications in Mass Spectrometry, 25, p. 3706-3712.

  1. Study on oil-water two-phase flow in horizontal pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Xiao-Xuan [Division of Oilfield Surface Engineering, Petroleum Exploration and Production Research Institute, SINOPEC, 31, Xue yuan Road, Haidian District, Beijing, 100083 (China)

    2007-10-15

    The simultaneous flow of oil and water in pipelines is a common occurrence in the petroleum industry. Water fractions in the output stream increase materially during the producing life of a well and many wells exist from which economic production can still persist with water volume fractions in the liquid phase in excess of 90%. The presence of water must be properly accounted for when designing and predicting the flow behavior in both wells and pipelines. This paper is aimed at giving a brief review on the research of oil-water pipe flows in the past decade. The contents are divided into three sections: (1) flow pattern identification and its transition; (2) phase inversion modeling; (3) pressure drop prediction. It is obvious that oil-water flow patterns, phase inversion prediction and pressure drop have played a great role in the design and running of oil-water flow systems. This paper critically reviews research achievement and presents the current trend in order to offer a guide in future research of the oil-water pipe flows. (author)

  2. Study on an Undershot Cross-Flow Water Turbine with Straight Blades

    OpenAIRE

    Yasuyuki Nishi; Terumi Inagaki; Yanrong Li; Kentaro Hatano

    2015-01-01

    Small-scale hydroelectric power generation has recently attracted considerable attention. The authors previously proposed an undershot cross-flow water turbine with a very low head suitable for application to open channels. The water turbine was of a cross-flow type and could be used in open channels with the undershot method, remarkably simplifying its design by eliminating guide vanes and the casing. The water turbine was fitted with curved blades (such as the runners of a typical cross-flo...

  3. Effect of Flow Rate of Side-Type Orifice Intake on Withdrawn Water Temperature

    OpenAIRE

    Xueping Gao; Guangning Li; Yunpeng Han

    2014-01-01

    Side-type orifice intake is a type of selective withdrawal facility used in managing reservoirs to mitigate the negative effects of low-temperature water. Based on the temperature data of a thermal stratified reservoir in China, an experiment was conducted in flume to study the influence of intake flow rate on withdrawn water temperature with different temperature distributions. Results indicated that withdrawn water temperature changed with different flow rates. The temperature change was de...

  4. Assessment of three turbulence model performances in predicting water jet flow plunging into a liquid pool

    OpenAIRE

    Zidouni Kendil Faiza; Bousbia Salah Anis; Mataoui Amina

    2010-01-01

    The main purpose of the current study is to numerically investigate, through computational fluid dynamics modeling, a water jet injected vertically downward through a straight circular pipe into a water bath. The study also aims to obtain a better understanding of jet behavior, air entrainment and the dispersion of bubbles in the developing flow region. For these purposes, three dimensional air and water flows were modeled using the volume of fluid technique. The equations in question were fo...

  5. Multiscale simulation of water flow past a C540 fullerene

    DEFF Research Database (Denmark)

    Walther, Jens Honore; Praprotnik, Matej; Kotsalis, Evangelos M.

    2012-01-01

    We present a novel, three-dimensional, multiscale algorithm for simulations of water flow past a fullerene. We employ the Schwarz alternating overlapping domain method to couple molecular dynamics (MD) of liquid water around the C540 buckyball with a Lattice–Boltzmann (LB) description for the Nav...... algorithms. We use this method to determine the slip length and hydrodynamic radius for water flow past a buckyball....

  6. The influence of the gas content of water and the flow velocity on cavitation erosion aggressiveness

    OpenAIRE

    Stoffel, Bernd; Širok, Brane; Dular, Matevž

    2015-01-01

    A study of the influence of the gas content of water and the flow velocity on cavitation erosion aggressiveness was performed. A cavitation tunnel with a single hydrofoil was used for the experiments. While the cavitation number andthe mean flow velocity remained constant throughout the tests, the gas content of the water was changed in steps from low (approximately 1%) to high (4 %). The gas content of the water was adjusted with a bubble generator. In addition tests at a constant cavitation...

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

    Science.gov (United States)

    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.

  8. Experimental study on improvement effect of guide wall to water flow in bend of spillway chute.

    Science.gov (United States)

    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.

  9. Importance of vegetation, topography and flow paths for water transit times of base flow in alpine headwater catchments

    Directory of Open Access Journals (Sweden)

    M. H. Mueller

    2013-04-01

    Full Text Available The mean transit time (MTT of water in a catchment gives information about storage, flow paths, sources of water and thus also about retention and release of solutes in a catchment. To our knowledge there are only a few catchment studies on the influence of vegetation cover changes on base flow MTTs. The main changes in vegetation cover in the Swiss Alps are massive shrub encroachment and forest expansion into formerly open habitats. Four small and relatively steep headwater catchments in the Swiss Alps (Ursern Valley were investigated to relate different vegetation cover to water transit times. Time series of water stable isotopes were used to calculate MTTs. The high temporal variation of the stable isotope signals in precipitation was strongly dampened in stream base flow samples. MTTs of the four catchments were 70 to 102 weeks. The strong dampening of the stable isotope input signal as well as stream water geochemistry points to deeper flow paths and mixing of waters of different ages at the catchments' outlets. MTTs were neither related to topographic indices nor vegetation cover. The major part of the quickly infiltrating precipitation likely percolates through fractured and partially karstified deeper rock zones, which increases the control of bedrock flow paths on MTT. Snow accumulation and the timing of its melt play an important role for stable isotope dynamics during spring and early summer. We conclude that, in mountainous headwater catchments with relatively shallow soil layers, the hydrogeological and geochemical patterns (i.e. geochemistry, porosity and hydraulic conductivity of rocks and snow dynamics influence storage, mixing and release of water in a stronger way than vegetation cover or topography do.

  10. Rerouting of subglacial water flow between neighboring glaciers in West Greenland

    Science.gov (United States)

    Chu, Winnie; Creyts, Timothy T.; Bell, Robin E.

    2016-05-01

    Investigations of the Greenland ice sheet's subglacial hydrological system show that the connectivity of different regions of the system influences how the glacier velocity responds to variations in surface melting. Here we examine whether subglacial water flow paths can be rerouted beneath three outlet glaciers in the ablation zone of western Greenland. We use Lamont-Doherty and Center for Remote Sensing of Ice Sheets of University of Kansas (CReSIS) ice-penetrating radar data to create a new ice thickness map. We then use a simple subglacial water flow model to examine whether flow paths can be rerouted and identify the topographic conditions that are sensitive to subglacial rerouting. By varying water pressures within an observationally constrained range, we show that moderate changes in pressure can cause flow paths to reroute and exchange water from one subglacial catchment to another. Flow across subglacial overdeepenings is particularly sensitive to rerouting. These areas have low hydraulic gradients driving flow, so subtle water pressure variations have a strong influence on water flow direction. Based on correlations between water flow paths and ice velocity changes, we infer that water piracy between neighboring catchments can result in a different spatial pattern of hydrologically induced ice velocity speedup depending on the amount and timing of surface melt. The potential for subglacial water to reroute across different catchments suggests that multiple hydrographs from neighboring glaciers are likely necessary to accurately ascertain melt budgets from proglacial point measurements. The relationship between surface runoff, ice dynamics, and proglacial discharge can be altered by rerouting of subglacial water flow within and across outlet glaciers.

  11. Heat flow and ground water flow in the Great Plains of the United States

    Science.gov (United States)

    Gosnold, William D.

    1985-12-01

    Regional groundwater flow in deep aquifers adds advective components to the surface heat flow over extensive areas within the Great Plains province. The regional groundwater flow is driven by topographically controlled piezometric surfaces for confined aquifers that recharge either at high elevations on the western edge of the province or from subcrop contacts. The aquifers discharge at lower elevations to the east. The assymetrical geometry for the Denver and Kennedy Basins is such that the surface areas of aquifer recharge are small compared to the areas of discharge. Consequently, positive advective heat flow occurs over most of the province. The advective component of heat flow in the Denver Basin is on the order of 15 mW m -2 along a zone about 50 km wide that parallels the structure contours of the Dakota aquifer on the eastern margin of the Basin. The advective component of heat flow in the Kennedy Basin is on the order of 20 mW m -2 and occurs over an extensive area that coincides with the discharge areas of the Madison (Mississippian) and Dakota (Cretaceous) aquifers. Groundwater flow in Paleozoic and Mesozoic aquifers in the Williston Basin causes thermal anomalies that are seen in geothermal gradient data and in oil well temperature data. The pervasive nature of advective heat flow components in the Great Plains tends to mask the heat flow structure of the crust, and only heat flow data from holes drilled into the crystalline basement can be used for tectonic heat flow studies.

  12. A fully coupled depth-integrated model for surface water and groundwater flows

    Science.gov (United States)

    Li, Yuanyi; Yuan, Dekui; Lin, Binliang; Teo, Fang-Yenn

    2016-11-01

    This paper presents the development of a fully coupled surface water and groundwater flow model. The governing equations of the model are derived based on a control volume approach, with the velocity profiles of the two types of flows being both taken into consideration. The surface water and groundwater flows are both modelled based on the unified equations and the water exchange and interaction between the two types of flows can be taken into account. The model can be used to simulate the surface water and groundwater flows simultaneously with the same numerical scheme without other effort being needed to link them. The model is not only suitable for the porous medium consisting of fine sediments, but also for coarse sediments and crushed rocks by adding a quadratic friction term. Benchmark tests are conducted to validate the model. The model predictions agree well with the data.

  13. Quantifying water flow and retention in an unsaturated fracture-facial domain

    Science.gov (United States)

    Nimmo, John R.; Malek-Mohammadi, Siamak

    2015-01-01

    Hydrologically significant flow and storage of water occur in macropores and fractures that are only partially filled. To accommodate such processes in flow models, we propose a three-domain framework. Two of the domains correspond to water flow and water storage in a fracture-facial region, in addition to the third domain of matrix water. The fracture-facial region, typically within a fraction of a millimeter of the fracture wall, includes a flowing phase whose fullness is determined by the availability and flux of preferentially flowing water, and a static storage portion whose fullness is determined by the local matric potential. The flow domain can be modeled with the source-responsive preferential flow model, and the roughness-storage domain can be modeled with capillary relations applied on the fracture-facial area. The matrix domain is treated using traditional unsaturated flow theory. We tested the model with application to the hydrology of the Chalk formation in southern England, coherently linking hydrologic information including recharge estimates, streamflow, water table fluctuation, imaging by electron microscopy, and surface roughness. The quantitative consistency of the three-domain matrix-microcavity-film model with this body of diverse data supports the hypothesized distinctions and active mechanisms of the three domains and establishes the usefulness of this framework.

  14. Influence of aeration and initial water thickness on axial velocity attenuation of jet flows

    Institute of Scientific and Technical Information of China (English)

    Wang-ru WEI; Jun DENG; Bin LIU

    2013-01-01

    With the development of ski-jump energy dissipation for high and large discharge among the hydraulic projects,the effects of characteristics of water flow on energy dissipation are increasingly important.In the present study,the effects of aeration and the initial water thickness on axial velocity attenuation of jet flow were analyzed,using variance analysis and numerical calculated methods.From the analysis of test data,both of the air concentration and initial water thickness are sensitive factors for the axial velocity attenuation of jet flow along the axial way,and there is no significant interaction effect between the aeration and initial water thickness.Aeration has a more significant effect on the axial velocity attenuation of jet flow.Decreasing the initial water thickness of jet flow can reduce the length of jet core,and make the initial position of axial velocity attenuation closer to the nozzle exit.The numerical calculation results show that aeration can contribute to the enhancement of entrainment ability of jet flow,which may improve the interaction between jet flow and surroundings.For ski-jump energy dissipation among the hydraulic projects,combining aeration with decreasing initial water thickness of jet flow is an effective way to enhance the rate of axial velocity attenuation.

  15. Statistical equilibria of the coupled barotropic flow and shallow water flow on a rotating sphere

    Science.gov (United States)

    Ding, Xueru

    The motivation of this research is to build equilibrium statistical models that can apply to explain two enigmatic phenomena in the atmospheres of the solar system's planets: (1) the super-rotation of the atmospheres of slowly-rotating terrestrial planets---namely Venus and Titan, and (2) the persistent anticyclonic large vortex storms on the gas giants, such as the Great Red Spot (GRS) on Jupiter. My thesis is composed of two main parts: the first part focuses on the statistical equilibrium of the coupled barotropic vorticity flow (non-divergent) on a rotating sphere; the other one has to do with the divergent shallow water flow rotating sphere system. The statistical equilibria of these two systems are simulated in a wide range of parameter space by Monte Carlo methods based on recent energy-relative enstrophy theory and extended energy-relative enstrophy theory. These kind of models remove the low temperatures defect in the old classical doubly canonical energy-enstrophy theory which cannot support any phase transitions. The other big difference of our research from previous work is that we work on the coupled fluid-sphere system, which consists of a rotating high density rigid sphere, enveloped by a thin shell of fluid. The sphere is considered to have infinite mass and angular momentum; therefore, it can serve as a reservoir of angular momentum. Unlike the fluid sphere system itself, the coupled fluid sphere system allows for the exchange of angular momentum between the atmosphere and the solid planet. This exchange is the key point in any model that is expected to capture coherent structures such as the super-rotation and GRS-like vortices problems in planetary atmospheres. We discovered that slowly-rotating planets can have super-rotation at high energy state. All known slowly-rotating cases in the solar system---Venus and Titan---have super-rotation. Moreover, we showed that the anticyclonicity in the GRS-like structures is closely associated with the

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

    Energy Technology Data Exchange (ETDEWEB)

    P. Tucci

    2001-12-20

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

  17. Ground-water flow and quality in Wisconsin's shallow aquifer system

    Science.gov (United States)

    Kammerer, P.A.

    1995-01-01

    The areal concentration distribution of commonmineral constituents and properties of ground water in Wisconsin's shallow aquifer system are described in this report. Maps depicting the water quality and the altitude of the water table are included. The shallow aquifer system in Wisconsin, composed of unconsolidated sand and gravel and shallow bedrock, is the source of most potable ground-water supplies in the State. Most ground water in the shallow aquifer system moves in local flow systems, but it interacts with regional flow systems in some areas.

  18. The effects of water flow and temperature on thermal regime around a culvert built on permafrost

    Institute of Scientific and Technical Information of China (English)

    Loriane Prier; Guy Dor; CR Burn

    2014-01-01

    Temperature and water flow through a culvert beneath the Alaska Highway near Beaver Creek, Yukon, were measured at hourly intervals between June and October 2013. These data were used to simulate the effect of the culvert on the thermal regime of the road embankment and subjacent permafrost. A 2-D thermal model of the embankment and permafrost was developed with TEMP/W and calibrated using field observations. Empirical relations were obtained between water tem-peratures at the entrance to the culvert, flow into the culvert, and water temperatures inside the structure. Water temper-atures at the entrance and inside the culvert had a linear relation, while water temperatures inside the culvert and water flow were associated by a logarithmic relation. A multiple linear regression was used to summarize these relations. From this relationship, changes in the flow rate and water temperatures at the entrance of the culvert were simulated to obtain pre-dicted water temperatures in the culvert. The temperatures in the culvert were used in the thermal model to determine their effects on the ground thermal regime near the culvert. Variation of ±10%in water flow rate had no impact on the thermal regime underneath the culvert. Variation of water temperature at the entrance of the culvert had a noticeable influence on the thermal regime. A final simulation was conducted without insulation beneath the culvert. The thaw depth was 30 cm with insulation, and 120 cm without insulation, illustrating the importance of insulation to the ground thermal regime.

  19. Advances of modeling water flow in variably saturated soils with SWAP

    NARCIS (Netherlands)

    Dam, van J.C.; Groenendijk, P.; Hendriks, R.F.A.; Kroes, J.G.

    2008-01-01

    The Soil Water Atmosphere Plant (SWAP) model simulates transport of water, solutes, and heat in the vadose zone in interaction with vegetation development. Special features of the model are generic crop growth, versatile top boundary conditions, macroporous flow, and interaction of soil water with g

  20. Geohydrology, simulation of ground-water flow, and ground-water quality at two landfills, Marion County, Indiana. Water Resources Investigation

    Energy Technology Data Exchange (ETDEWEB)

    Duwelius, R.F.; Greeman, T.K.

    1989-01-01

    The report presents the results of a study to provide a quantitative evaluation of the ground-water flow system at the Julietta and Tibbs-Banta landfills and provide a general description of the ground-water quality beneath and near the two landfills. These objectives provide the information necessary to evaluate the effects of the landfills on ground-water quality. Geologic, hydrologic, and water-quality data were collected in 1985 and 1986 at the Julietta and Tibbs-Banta landfills to fulfill the study objectives. Ground-water models were used to investigate the flow systems and estimate the volume of flow at the landfills. The report includes descriptions of the data collection, geologic and hydrologic descriptions of the two landfills, and brief histories of trash and sludge disposal. Ground-water-flow models are described and estimates of the volume of flow are discussed. A description of the quality-assurance plan used in conjunction with the water-quality data collection and analysis is included. Water-quality data are presented with statistical summaries of ground-water quality related to well depth and position in the flow system.

  1. EXPERIMENTAL INVESTIGATIONS OF CAVITATION EFFECTS ON FLOW CHARACTERISTICS OF SMALL ORIFICES AND VALVES IN WATER HYDRAULICS

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The flow characteristics and cavitation effects of water passing through small sharp-edged cylindrical orificesand valves of different shapes in water hydraulics are investigated. The test results using orifices with different aspect ra-tios and different diameters show that the flow coefficients in the case of non-cavitating flow are larger than that of row inthe case of cavitation occurrence. The flow coefficients of flow with cavitation initially decrease as Reynolds number in-creases and ultimately tend to be of constant values close to contraction coefficient. Large aspect ratio has an effect ofsuppressing cavitation. The experimental results about disc valves illustrate that the valves with sharp edge at large open-ing are less affected by cavitation than that at small opening. Throttle with triangle notch has better anti-cavitation abilitythan that with square notch. The flowrate of the throttle with square notch is significantly affected by the flow direction orthe flow passage shape.

  2. Numerical simulation of air-water two-phase flow over stepped spillways

    Institute of Scientific and Technical Information of China (English)

    CHENG; Xiangju; CHEN; Yongcan

    2006-01-01

    Stepped spillways for significant energy dissipation along the chute have gained interest and popularity among researchers and dam engineers. Due to the complexity of air-water two-phase flow over stepped spillways, the finite volume computational fluid dynamics module of the FLUENT software was used to simulate the main characteristics of the flow. Adopting the RNG k-ε turbulence model, the mixture flow model for air-water two-phase flow was used to simulate the flow field over stepped spillway with the PISO arithmetic technique. The numerical result successfully reproduced the complex flow over a stepped spillway of an experiment case, including the interaction between entrained air bubbles and cavity recirculation in the skimming flow regime, velocity distribution and the pressure profiles on the step surface as well. The result is helpful for understanding the detailed information about energy dissipation over stepped spillways.

  3. Fire flow water consumption in sprinklered and unsprinklered buildings an assessment of community impacts

    CERN Document Server

    Code Consultants, Inc.

    2012-01-01

    Fire Flow Water Consumption in Sprinklered and Unsprinklered Buildings offers a detailed analysis for calculating the fire water demand required in buildings with existing and non-existant sprinkler systems. The installation of automatic sprinkler systems can significantly reduce the amount of water needed during a fire, but it requires water for commissioning, inspection, testing, and maintenance (CITM). This book provides an estimate of fire water used under both fire conditions, including CITM, to allow communities to develop fire water fees for both sprinklered and unsprinklered buildings that are proportional to the anticipated fire water usage. The types of buildings analyzed include residential (family dwellings as well as those up to four stories in height), business, assembly, institutional, mercantile, and storage facilities. Water volume was studied using guidelines from the International Code Council, the National Fire Protection Association, and the Insurance Services Office. Fire Flow Water Cons...

  4. Flow cytometry total cell counts: a field study assessing microbiological water quality and growth in unchlorinated drinking water distribution systems

    NARCIS (Netherlands)

    Liu, G.; Van der Mark, E.J.; Verberk, J.Q.; Van Dijk, J.C.

    2013-01-01

    e objective of this study was to evaluate the application of flow cytometry total cell counts (TCCs) as a parameter to assess microbial growth in drinking water distribution systems and to determine the relationships between different parameters describing the biostability of treated water. A one-ye

  5. Snow-mold-induced apoplastic proteins in winter rye leaves lack antifreeze activity

    Science.gov (United States)

    Hiilovaara-Teijo; Hannukkala; Griffith; Yu; Pihakaski-Maunsbach

    1999-10-01

    During cold acclimation, winter rye (Secale cereale L.) plants secrete antifreeze proteins that are similar to pathogenesis-related (PR) proteins. In this experiment, the secretion of PR proteins was induced at warm temperatures by infection with pink snow mold (Microdochium nivale), a pathogen of overwintering cereals. A comparison of cold-induced and pathogen-induced proteins showed that PR proteins accumulated in the leaf apoplast to a greater level in response to cold. The PR proteins induced by cold and by snow mold were similar when separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and examined by immunoblotting. Both groups of PR proteins contained glucanase-like, chitinase-like, and thaumatin-like proteins, and both groups exhibited similar levels of glucanase and chitinase activities. However, only the PR proteins induced by cold exhibited antifreeze activity. Our findings suggest that the cold-induced PR proteins may be isoforms that function as antifreeze proteins to modify the growth of ice during freezing while also providing resistance to the growth of low-temperature pathogens in advance of infection. Both functions of the cold-induced PR proteins may improve the survival of overwintering cereals.

  6. Dissecting the variable source area concept - Subsurface flow pathways and water mixing processes in a hillslope

    Science.gov (United States)

    Dahlke, Helen E.; Easton, Zachary M.; Lyon, Steve W.; Todd Walter, M.; Destouni, Georgia; Steenhuis, Tammo S.

    2012-02-01

    SummaryThis study uses an instrumented (trenched) 0.5 ha hillslope in the southern tier of New York State, USA, to provide new data and insights on how variable source areas and associated flow pathways form and combine to connect rainfall with downstream water flows across a hillslope. Measurements of water fluxes in the trench, upslope water table dynamics, surface and bedrock topography, and isotopic and geochemical tracers have been combined for a four-dimensional (space-time) characterization of subsurface storm flow responses. During events with dry antecedent conditions infiltrating rainwater was found to percolate through a prevailing fragipan layer to deeper soil layers, with much (33-71%) of the total discharge of the hillslope originating from deeper water flow below the fragipan. During storm events with wet antecedent conditions and large rainfall amounts, shallow lateral flow of event and pre-event water above the fragipan occurred and was one magnitude greater than the deeper water flow contribution. Spatial surface and subsurface water quality observations indicate that water from a distance of up to 56 m contributed runoff from the hillslope during storm events. In addition, mobilization of total dissolved phosphorus (TDP) with subsurface flow played a greater role than with overland or near-surface flow. During all events TDP loads were highest in the total discharge during peak flows (8-11.5 kg ha -1 d -1), except during the largest storm event, when TDP concentrations were highly diluted. These results have implications for strategies to protect streams and other downstream water recipients from waterborne nutrient and pollutant loading.

  7. High-Resolution Numerical Model for Shallow Water Flows and Pollutant Diffusions

    Institute of Scientific and Technical Information of China (English)

    王嘉松; 何友声

    2002-01-01

    A finite-volume high-resolution numerical model for coupling the shallow water flows and pollutant diffusions was presented based on using a hybrid TVD scheme in space discretization and a Runge-Kutta method in time discretization. Numerical simulations for modelling dam- break, enlarging open channel flow and pollutant dispersion were implemented and compared with experimental data or other published computations. The validation of this method shows that it can not only deal with the problem involving discontinuities and unsteady flows, but also solve the general shallow water flows and pollutant diffusions.

  8. Core Flow Distribution from Coupled Supercritical Water Reactor Analysis

    Directory of Open Access Journals (Sweden)

    Po Hu

    2014-01-01

    Full Text Available This paper introduces an extended code package PARCS/RELAP5 to analyze steady state of SCWR US reference design. An 8 × 8 quarter core model in PARCS and a reactor core model in RELAP5 are used to study the core flow distribution under various steady state conditions. The possibility of moderator flow reversal is found in some hot moderator channels. Different moderator flow orifice strategies, both uniform across the core and nonuniform based on the power distribution, are explored with the goal of preventing the reversal.

  9. A genetic screen reveals Arabidopsis stomatal and/or apoplastic defenses against Pseudomonas syringae pv. tomato DC3000.

    Directory of Open Access Journals (Sweden)

    Weiqing Zeng

    2011-10-01

    Full Text Available Bacterial infection of plants often begins with colonization of the plant surface, followed by entry into the plant through wounds and natural openings (such as stomata, multiplication in the intercellular space (apoplast of the infected tissues, and dissemination of bacteria to other plants. Historically, most studies assess bacterial infection based on final outcomes of disease and/or pathogen growth using whole infected tissues; few studies have genetically distinguished the contribution of different host cell types in response to an infection. The phytotoxin coronatine (COR is produced by several pathovars of Pseudomonas syringae. COR-deficient mutants of P. s. tomato (Pst DC3000 are severely compromised in virulence, especially when inoculated onto the plant surface. We report here a genetic screen to identify Arabidopsis mutants that could rescue the virulence of COR-deficient mutant bacteria. Among the susceptible to coronatine-deficient Pst DC3000 (scord mutants were two that were defective in stomatal closure response, two that were defective in apoplast defense, and four that were defective in both stomatal and apoplast defense. Isolation of these three classes of mutants suggests that stomatal and apoplastic defenses are integrated in plants, but are genetically separable, and that COR is important for Pst DC3000 to overcome both stomatal guard cell- and apoplastic mesophyll cell-based defenses. Of the six mutants defective in bacterium-triggered stomatal closure, three are defective in salicylic acid (SA-induced stomatal closure, but exhibit normal stomatal closure in response to abscisic acid (ABA, and scord7 is compromised in both SA- and ABA-induced stomatal closure. We have cloned SCORD3, which is required for salicylic acid (SA biosynthesis, and SCORD5, which encodes an ATP-binding cassette (ABC protein, AtGCN20/AtABCF3, predicted to be involved in stress-associated protein translation control. Identification of SCORD5 begins to

  10. Ground water flow in a desert basin: challenges of simulating transport of dissolved chromium.

    Science.gov (United States)

    Andrews, Charles B; Neville, Christopher J

    2003-01-01

    A large chromium plume that evolved from chromium releases in a valley near the Mojave River was studied to understand the processes controlling fate and migration of chromium in ground water and used as a tracer to study the dynamics of a basin and range ground water system. The valley that was studied is naturally arid with high evapotranspiration such that essentially no precipitation infiltrates to the water table. The dominant natural hydrogeologic processes are recharge to the ground water system from the Mojave River during the infrequent episodes when there is flow in the river, and ground water flow toward a playa lake where the ground water evaporates. Agricultural pumping in the valley from the mid-1930s to the 1970s significantly altered ground water flow conditions by decreasing water levels in the valley by more than 20 m. This pumping declined significantly as a result of dewatering of the aquifer, and water levels have since recovered modestly. The ground water system was modeled using MODFLOW, and chromium transport was simulated using MT3D. Several innovative modifications were made to these modeling programs to simulate important processes in this ground water system. Modifications to MODFLOW include developing a new well package that estimates pumping rates from irrigation wells at each time step based on available drawdown. MT3D was modified to account for mass trapped above the water table when the water table declines beneath nonirrigated areas and to redistribute mass to the system when water levels rise.

  11. Computing equations of water hammer in pseudo-homogeneous solid-liquid flow and their verification

    Institute of Scientific and Technical Information of China (English)

    韩文亮; 董曾南; 柴宏恩; 韩军

    2000-01-01

    In engineering practice, single-phase water hammer models are still employed to analyze the water hammer of solid-liquid flow. According to the characteristics of solid-liquid flow, continuity equations and momentum equations of pseudo-homogeneous flows are deduced, and a pseudo-homogeneous water hammer model is thus built and verified with experiment results. The characteristics of solid-liquid flow’s viscosity, resistance and wave velocity are considered in the model. Therefore, it has higher precision than a single-phase model.

  12. A Computer Program to Calculate the Supersonic Flow over a Solid Cone in Air or Water.

    Science.gov (United States)

    1984-06-01

    ix air or water. The rain objective is to calculate the ccne semi-vertei angle given prescribed initial ccndi- tions. The program is written in...tc the motion of the metal jet frcm an explczive shaped-charge fired underwater. A tiical result for supersonic flow over a ccne in water is as follcws...the ccne semi-vertex angle is calculated to be 7.23 degrees. Gene rally, pressures invclved in water flow are much larger than for air flow, and the

  13. Quantifying green water flows for improved Integrated Land and Water Resource Management under the National Water Act of South Africa: A review on hydrological research in South Africa.

    Science.gov (United States)

    Jarmain, C.; Everson, C. S.; Gush, M. B.; Clulow, A. D.

    2009-09-01

    The contribution of hydrological research in South Africa in quantifying green water flows for improved Integrated Land and Water Resources Management is reviewed. Green water refers to water losses from land surfaces through transpiration (seen as a productive use) and evaporation from bare soil (seen as a non-productive use). In contrast, blue water flows refer to streamflow (surface water) and groundwater / aquifer recharge. Over the past 20 years, a number of methods have been used to quantify the green water and blue water flows. These include micrometeorological techniques (e.g. Bowen ratio energy balance, eddy covariance, surface renewal, scintillometry, lysimetry), field scale models (e.g. SWB, SWAP), catchment scale hydrological models (e.g. ACRU, SWAT) and more recently remote sensing based models (e.g. SEBAL, SEBS). The National Water Act of South Africa of 1998 requires that water resources are managed, protected and used (developed, conserved and controlled) in an equitable way which is beneficial to the public. The quantification of green water flows in catchments under different land uses has been pivotal in (a) regulating streamflow reduction activities (e.g. forestry) and the management of alien invasive plants, (b) protecting riparian and wetland areas through the provision of an ecological reserve, (c) assessing and improving the water use efficiency of irrigated pastures, fruit tree orchards and vineyards, (d) quantifying the potential impact of future land uses like bio-fuels (e.g. Jatropha) on water resources, (e) quantifying water losses from open water bodies, and (f) investigating "biological” mitigation measures to reduce the impact of polluted water resources as a result of various industries (e.g. mining). This paper therefore captures the evolution of measurement techniques applied across South Africa, the impact these results have had on water use and water use efficiency and the extent to which it supported the National Water Act of

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

  16. Simulated ground-water flow and water quality of the Mississippi River alluvium near Burlington, Iowa, 1999

    Science.gov (United States)

    Boyd, Robert A.

    2001-01-01

    The City of Burlington, Iowa, obtains some of its public water supply by withdrawing ground water from the Mississippi River alluvium, an alluvial aquifer adjacent to the Mississippi River. The U.S. Geological Survey, in cooperation with the City of Burlington, conducted a hydrologic study of the Mississippi River alluvium near Burlington in 1999 to improve understanding of the flow system, evaluate the effects of hypothetical pumping scenarios on the flow system, and evaluate selected water-quality constituents in parts of the alluvium.

  17. Well logging interpretation of production profile in horizontal oil-water two phase flow pipes

    Science.gov (United States)

    Zhai, Lu-Sheng; Jin, Ning-De; Gao, Zhong-Ke; Zheng, Xi-Ke

    2012-03-01

    Due to the complicated distribution of local velocity and local phase hold up along the radial direction of pipe in horizontal oil-water two phase flow, it is difficult to measure the total flow rate and phase volume fraction. In this study, we carried out dynamic experiment in horizontal oil-water two phases flow simulation well by using combination measurement system including turbine flowmeter with petal type concentrating diverter, conductance sensor and flowpassing capacitance sensor. According to the response resolution ability of the conductance and capacitance sensor in different range of total flow rate and water-cut, we use drift flux model and statistical model to predict the partial phase flow rate, respectively. The results indicate that the variable coefficient drift flux model can self-adaptively tone the model parameter according to the oil-water two phase flow characteristic, and the prediction result of partial phase flow rate of oil-water two phase flow is of high accuracy.

  18. Understanding virtual water flows: A multiregion input-output case study of Victoria

    Science.gov (United States)

    Lenzen, Manfred

    2009-09-01

    This article explains and interprets virtual water flows from the well-established perspective of input-output analysis. Using a case study of the Australian state of Victoria, it demonstrates that input-output analysis can enumerate virtual water flows without systematic and unknown truncation errors, an issue which has been largely absent from the virtual water literature. Whereas a simplified flow analysis from a producer perspective would portray Victoria as a net virtual water importer, enumerating the water embodiments across the full supply chain using input-output analysis shows Victoria as a significant net virtual water exporter. This study has succeeded in informing government policy in Australia, which is an encouraging sign that input-output analysis will be able to contribute much value to other national and international applications.

  19. A COUPLING MODEL OF WATER FLOWS AND GAS FLOWS IN EXHAUSTED GAS BUBBLE ON MISSILE LAUNCHED UNDERWATER

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The gas and water flows during an underwater missile launch are numerically studied. For the gas flow, the explicit difference scheme of Non-oscillation and Non-free-parameter Dissipation (NND) is utilized to solve the Euler equations for compressible fluids in the body-fitted coordinates. For the water flow, the Hess-Smith method is employed to solve the Laplace equation for the velocity potential of irrotational water flows based on the potential theory and the boundary element method. The hybrid Eulerian-Lagrangian formulation for the free boundary conditions is used to compute the changes of the free surface of the exhausted gas bubble in time stepping. On the free surface of the exhausted gas bubble, the matched conditions of both the normal velocities and pressures are satisfied. From the numerical simulation, it is found that the exhausted gas bubble grows more rapidly in the axial direction than in the radial direction and the bubble will shrink at its "neck" finally. Numerical results of the movement of the shock wave and the distribution of the Mach number and the gas pressure within the bubble were presented, which reveals that at some time, the gas flow in the Laval nozzle is subsonic and the gas pressure in the nozzle is very high. Influences of various initial missile velocities and chamber total pressures and water depths on both the time interval when the gas flow in the nozzle is subsonic and the peak of the gas pressure at the nozzle end were discussed. It was suggested that a reasonable adjustment of the chamber total pressure can improve the performance of the engine during the underwater launch of missiles.

  20. Spermidine exodus and oxidation in the apoplast induced by abiotic stress is responsible for H2O2 signatures that direct tolerance responses in tobacco.

    Science.gov (United States)

    Moschou, Panagiotis N; Paschalidis, Konstantinos A; Delis, Ioannis D; Andriopoulou, Athina H; Lagiotis, George D; Yakoumakis, Dimitrios I; Roubelakis-Angelakis, Kalliopi A

    2008-06-01

    Polyamines (PAs) exert a protective effect against stress challenges, but their molecular role in this remains speculative. In order to detect the signaling role of apoplastic PA-derived hydrogen peroxide (H2O2) under abiotic stress, we developed a series of tobacco (Nicotiana tabacum cv Xanthi) transgenic plants overexpressing or downregulating apoplastic polyamine oxidase (PAO; S-pao and A-pao plants, respectively) or downregulating S-adenosyl-l-methionine decarboxylase (samdc plants). Upon salt stress, plants secreted spermidine (Spd) into the apoplast, where it was oxidized by the apoplastic PAO, generating H2O2. A-pao plants accumulated less H2O2 and exhibited less programmed cell death (PCD) than did wild-type plants, in contrast with S-pao and samdc downregulating plants. Induction of either stress-responsive genes or PCD was dependent on the level of Spd-derived apoplastic H2O2. Thus, in wild-type and A-pao plants, stress-responsive genes were efficiently induced, although in the latter at a lower rate, while S-pao plants, with higher H2O2 levels, failed to accumulate stress-responsive mRNAs, inducing PCD instead. Furthermore, decreasing intracellular PAs, while keeping normal apoplastic Spd oxidation, as in samdc downregulating transgenic plants, caused enhanced salinity-induced PCD. These results reveal that salinity induces the exodus of Spd into the apoplast, where it is catabolized by PAO, producing H2O2. The accumulated H2O2 results in the induction of either tolerance responses or PCD, depending also on the levels of intracellular PAs.

  1. Topology and stability of a water-soybean-oil swirling flow

    Science.gov (United States)

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

    2017-02-01

    This paper reveals and explains the flow topology and instability hidden in an experimental study by Tsai et al. [Tsai et al., Phys. Rev. E 92, 031002(R) (2015)], 10.1103/PhysRevE.92.031002. Water and soybean oil fill a sealed vertical cylindrical container. The rotating top disk induces the meridional circulation and swirl of both fluids. The experiment shows a flattop interface shape and vortex breakdown in the oil flow developing as the rotation strength R eo increases. Our numerical study shows that vortex breakdown occurs in the water flow at R eo=300 and in the oil flow at R eo=941 . As R eo increases, the vortex breakdown cell occupies most of the water domain and approaches the interface at R eo around 600. The rest of the (countercirculating) water separates from the axis as the vortex breakdown cells in the oil and water meet at the interface-axis intersection. This topological transformation of water flow significantly contributes to the development of the flattop shape. It is also shown that the steady axisymmetric flow suffers from shear-layer instability, which emerges in the water domain at R eo=810 .

  2. Effects of salinity variations on pore water flow in salt marshes

    Science.gov (United States)

    Shen, Chengji; Jin, Guangqiu; Xin, Pei; Kong, Jun; Li, Ling

    2015-06-01

    Spatial and temporal salinity variations in surface water and pore water commonly exist in salt marshes under the combined influence of tidal inundation, precipitation, evapotranspiration, and inland freshwater input. Laboratory experiments and numerical simulations were conducted to investigate how density gradients associated with salinity variations affect pore water flow in the salt marsh system. The results showed that upward salinity (density) gradients could lead to flow instability and the formation of salt fingers. These fingers, varying in size with the distance from the creek, modified significantly the pore water flow field, especially in the marsh interior. While the flow instability enhanced local salt transport and mixing considerably, the net effect was small, causing only a slight increase in the overall mass exchange across the marsh surface. In contrast, downward salinity gradients exerted less influence on the pore water flow in the marsh soil and slightly weakened the surface water and groundwater exchange across the marsh surface. Numerical simulations revealed similar density effects on pore water flow at the field scale under realistic conditions. These findings have important implications for studies of marsh soil conditions concerning plant growth as well as nutrient exchange between the marsh and coastal marine system.

  3. Flow resistance characteristics of water in narrow annulus during heat exchange

    Institute of Scientific and Technical Information of China (English)

    SUN Li-cheng; YAN Chang-qi; SUN Zhong-ning; ZHANG Qing-hua

    2003-01-01

    Considering the special resistance characteristics of fluids flowing through ducts with small gaps, experiments are performed to investigate the resistance characteristics of single-phase water, which is forced to flow through vertical annuli. The gap sizes are 0.9, 1.4 and 2.4mm, respectively. The experiments are conducted under condition of 1atm. The water in the annuli is heated by high temperature water reversely flowing through the inner tube and the outer annulus. The results show that the flow pattern begin to change from laminar to turbulent before Reynolds number approaches 2000, the flow resistance in annulus has little relations with the temperature difference and ways of being heated, but mainly depends on the ratio of mass flux to the width of annulus.

  4. A flow channel design procedure for PEM fuel cells with effective water removal

    Science.gov (United States)

    Li, Xianguo; Sabir, Imran; Park, Jaewan

    Proper water management in polymer electrolyte membrane (PEM) fuel cells is critical to achieve the potential of PEM fuel cells. Membrane electrolyte requires full hydration in order to function as proton conductor, often achieved by fully humidifying the anode and cathode reactant gas streams. On the other hand, water is also produced in the cell due to electrochemical reaction. The combined effect is that liquid water forms in the cell structure and water flooding deteriorates the cell performance significantly. In the present study, a design procedure has been developed for flow channels on bipolar plates that can effectively remove water from the PEM fuel cells. The main design philosophy is based on the determination of an appropriate pressure drop along the flow channel so that all the liquid water in the cell is evaporated and removed from, or carried out of, the cell by the gas stream in the flow channel. At the same time, the gas stream in the flow channel is maintained fully saturated in order to prevent membrane electrolyte dehydration. Sample flow channels have been designed, manufactured and tested for five different cell sizes of 50, 100, 200, 300 and 441 cm 2. Similar cell performance has been measured for these five significantly different cell sizes, indicating that scaling of the PEM fuel cells is possible if liquid water flooding or membrane dehydration can be avoided during the cell operation. It is observed that no liquid water flows out of the cell at the anode and cathode channel exits for the present designed cells during the performance tests, and virtually no liquid water content in the cell structure has been measured by the neutron imaging technique. These measurements indicate that the present design procedure can provide flow channels that can effectively remove water in the PEM fuel cell structure.

  5. A flow channel design procedure for PEM fuel cells with effective water removal

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xianguo; Sabir, Imran; Park, Jaewan [Department of Mechanical Engineering, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada)

    2007-01-01

    Proper water management in polymer electrolyte membrane (PEM) fuel cells is critical to achieve the potential of PEM fuel cells. Membrane electrolyte requires full hydration in order to function as proton conductor, often achieved by fully humidifying the anode and cathode reactant gas streams. On the other hand, water is also produced in the cell due to electrochemical reaction. The combined effect is that liquid water forms in the cell structure and water flooding deteriorates the cell performance significantly. In the present study, a design procedure has been developed for flow channels on bipolar plates that can effectively remove water from the PEM fuel cells. The main design philosophy is based on the determination of an appropriate pressure drop along the flow channel so that all the liquid water in the cell is evaporated and removed from, or carried out of, the cell by the gas stream in the flow channel. At the same time, the gas stream in the flow channel is maintained fully saturated in order to prevent membrane electrolyte dehydration. Sample flow channels have been designed, manufactured and tested for five different cell sizes of 50, 100, 200, 300 and 441cm{sup 2}. Similar cell performance has been measured for these five significantly different cell sizes, indicating that scaling of the PEM fuel cells is possible if liquid water flooding or membrane dehydration can be avoided during the cell operation. It is observed that no liquid water flows out of the cell at the anode and cathode channel exits for the present designed cells during the performance tests, and virtually no liquid water content in the cell structure has been measured by the neutron imaging technique. These measurements indicate that the present design procedure can provide flow channels that can effectively remove water in the PEM fuel cell structure. (author)

  6. Numerical study of water management in the air flow channel of a PEM fuel cell cathode

    Energy Technology Data Exchange (ETDEWEB)

    Quan, Peng; Lai, Ming-Chia [Department of Mechanical Engineering, Wayne State University, Detroit, MI 48202 (United States)

    2007-01-10

    The water management in the air flow channel of a proton exchange membrane (PEM) fuel cell cathode is numerically investigated using the FLUENT software package. By enabling the volume of fraction (VOF) model, the air-water two-phase flow can be simulated under different operating conditions. The effects of channel surface hydrophilicity, channel geometry, and air inlet velocity on water behavior, water content inside the channel, and two-phase pressure drop are discussed in detail. The results of the quasi-steady-state simulations show that: (1) the hydrophilicity of reactant flow channel surface is critical for water management in order to facilitate water transport along channel surfaces or edges; (2) hydrophilic surfaces also increase pressure drop due to liquid water spreading; (3) a sharp corner channel design could benefit water management because it facilitates water accumulation and provides paths for water transport along channel surface opposite to gas diffusion layer; (4) the two-phase pressure drop inside the air flow channel increases almost linearly with increasing air inlet velocity. (author)

  7. Flow system boundary by D'Agnese and others (1997) for the Death Valley regional ground-water flow system study, Nevada and California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This digital data set defines the flow-system boundary encompassing the regional ground-water flow model by D'Agnese and others (1997). The boundary encompasses an...

  8. Study area boundary for the Death Valley regional ground-water flow system, Nevada and California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This digital data set represents the Death Valley regional ground-water flow system (DVRFS) study area which encompasses approximately 100,000-square kilometers in...

  9. Water Level Altitude Contours for the Diamond Valley Flow System, Central Nevada, 2012

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data were created as part of a hydrologic study to characterize groundwater budgets and water quality in the Diamond Valley Flow System (DVFS), central Nevada....

  10. Hydrogeologic map of the Death Valley regional ground-water flow system, Nevada and California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This digital dataset represents the surface hydrogeology of an approximately 45,000 square-kilometer area of the Death Valley regional ground-water flow system...

  11. Net infiltration of the Death Valley regional ground-water flow system, Nevada and California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Recharge in the Death Valley regional ground-water flow system (DVRFS) was estimated from net infiltration simulated by Hevesi and others (2003) using a...

  12. A criterion for the onset of slugging in horizontal stratified air-water countercurrent flow

    Energy Technology Data Exchange (ETDEWEB)

    Chun, Moon-Hyun; Lee, Byung-Ryung; Kim, Yang-Seok [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)] [and others

    1995-09-01

    This paper presents an experimental and theoretical investigation of wave height and transition criterion from wavy to slug flow in horizontal air-water countercurrent stratified flow conditions. A theoretical formula for the wave height in a stratified wavy flow regime has been developed using the concept of total energy balance over a wave crest to consider the shear stress acting on the interface of two fluids. From the limiting condition of the formula for the wave height, a necessary criterion for transition from a stratified wavy flow to a slug flow has been derived. A series of experiments have been conducted changing the non-dimensional water depth and the flow rates of air in a horizontal pipe and a duct. Comparisons between the measured data and the predictions of the present theory show that the agreement is within {plus_minus}8%.

  13. Macropore-mesopore model of water flow through aggregated porous media

    Energy Technology Data Exchange (ETDEWEB)

    Fong, L.; Appelbaum, H.R.

    1980-12-01

    A combined, one-dimensional, macropore-mesopore, hydrologic model was developed for simulating water flow through soils for analysis of data related to water and chemical flow in soils. Flows within the macroporous system as well as interactive flows between macroporous and mesoporous systems were modeled. Computer subroutines were written and incorporated into the existing one-dimensional Terrestrial Ecosystem Hydrologic Model (TEHM) developed at ORNL. Simulation showed that macropore flow effects are important during heavy precipitation and are more significant in soils of comparatively low hydraulic conductivity (5 to 10 cm/d). Increased drainage and decreased lateral flow result from the addition of the macropore model. The effect was more pronounced in soils of large macroporosity. Preliminary results indicate that the model is insensitive to geometrical properties of macropores.

  14. A Model of Debris Flow Forecast Based on the Water-Soil Coupling Mechanism

    Institute of Scientific and Technical Information of China (English)

    Shaojie Zhang; Hongjuan Yang; Fangqiang Wei; Yuhong Jiang; Dunlong Liu

    2014-01-01

    Debris flow forecast is an important means of disaster mitigation. However, the accuracy of the statistics-based debris flow forecast is unsatisfied while the mechanism-based forecast is un-available at the watershed scale because most of existing researches on the initiation mechanism of de-bris flow took a single slope as the main object. In order to solve this problem, this paper developed a model of debris flow forecast based on the water-soil coupling mechanism at the watershed scale. In this model, the runoff and the instable soil caused by the rainfall in a watershed is estimated by the distrib-uted hydrological model (GBHM) and an instable identification model of the unsaturated soil. Because the debris flow is a special fluid composed of soil and water and has a bigger density, the density esti-mated by the runoff and instable soil mass in a watershed under the action of a rainfall is employed as a key factor to identify the formation probability of debris flow in the forecast model. The Jiangjia Gulley, a typical debris flow valley with a several debris flow events each year, is selected as a case study wa-tershed to test this forecast model of debris flow. According the observation data of Dongchuan Debris Flow Observation and Research Station, CAS located in Jiangjia Gulley, there were 4 debris flow events in 2006. The test results show that the accuracy of the model is satisfied.

  15. Water flow and hydraulic characteristics of Japanese red pine and oak trees

    Science.gov (United States)

    Kobayashi, Yoshikazu; Tanaka, Tadashi

    2001-07-01

    To assess the characteristics of water flow in a tree and the contribution of the stem water storage to transpiration, some field observations were carried out in two natural forests: a Japanese red pine (Pinus densiflora Sieb. et Zucc.) forest and an oak (Quercus mongolica Fish) forest. Water potentials of leaf, stem, root and soil water, sap flow rate, volumetric water content of the stem and micrometeorological factors were measured during the observation periods. Clear diurnal variations in volumetric water content of a stem were observed. It was confirmed that water storage in the stem contributed to the transpiration process. This contribution appeared when the difference in water potential between the root and stem was more than 0·3 MPa. The stem water storage was extracted by the driving force due to the difference of the response of the root and stem water potential to change in the leaf water potential in daytime. The stem capacitance of 1·44 kg MPa-1 for the Japanese red pine and 0·44 kg MPa-1 for the oak were evaluated from the variation in the water storage in the stem and the difference of water potential between root and stem. Evaluations of the water budget were made for each test stand. The results indicated that the contribution of water storage in the stem to transpiration accounted for 10 to 20% of the daily transpiration.

  16. Hydrogeology, simulated ground-water flow, and ground-water quality, Wright-Patterson Air Force Base, Ohio

    Science.gov (United States)

    Dumouchelle, D.H.; Schalk, C.W.; Rowe, G.L.; De Roche, J.T.

    1993-01-01

    Ground water is the primary source of water in the Wright-Patterson Air Force Base area. The aquifer consists of glacial sands and gravels that fill a buried bedrock-valley system. Consolidated rocks in the area consist of poorly permeable Ordovician shale of the Richmondian stage, in the upland areas, the Brassfield Limestone of Silurian age. The valleys are filled with glacial sediments of Wisconsinan age consisting of clay-rich tills and coarse-grained outwash deposits. Estimates of hydraulic conductivity of the shales based on results of displacement/recovery tests range from 0.0016 to 12 feet per day; estimates for the glacial sediments range from less than 1 foot per day to more than 1,000 feet per day. Ground water flow from the uplands towards the valleys and the major rivers in the region, the Great Miami and the Mad Rivers. Hydraulic-head data indicate that ground water flows between the bedrock and unconsolidated deposits. Data from a gain/loss study of the Mad River System and hydrographs from nearby wells reveal that the reach of the river next to Wright-Patterson Air Force Base is a ground-water discharge area. A steady-state, three-dimensional ground-water-flow model was developed to simulate ground-water flow in the region. The model contains three layers and encompasses about 100 square miles centered on Wright-Patterson Air Force Base. Ground water enters the modeled area primarily by river leakage and underflow at the model boundary. Ground water exits the modeled area primarily by flow through the valleys at the model boundaries and through production wells. A model sensitivity analysis involving systematic changes in values of hydrologic parameters in the model indicates that the model is most sensitive to decreases in riverbed conductance and vertical conductance between the upper two layers. The analysis also indicates that the contribution of water to the buried-valley aquifer from the bedrock that forms the valley walls is about 2 to 4

  17. The Vertical Structure of Shallow Water Flow in the Surf Zone and Inner Shelf

    Science.gov (United States)

    2008-01-01

    E. Richardson, 2008, Field verification of a CFD model for wave transformation and breaking in the surf zone, J. Waterw. Port Coastal Engrg., 134(2...The Vertical Structure of Shallow Water Flow in the Surf Zone and Inner Shelf Dr. Thomas C. Lippmann Center for Coastal...wave- and tidally-driven shallow water flows in the shallow depths of the inner shelf and surf zone. OBJECTIVES 1. Theoretical investigations of

  18. Flow resistance reduction of coal water slurry through gas phase addition

    OpenAIRE

    Robak Jolanta; Ignasiak Karina

    2016-01-01

    One of the main advantages of coal water slurry fuel (CWS) is a physical form that allows, among others, their transfer by pipelines over long distances. For this form of transport actions towards reducing the flow resistance of the transmitted medium are important. One of the treatments leading to reduction in the flow resistance of suspensions is to introduce gas into the stream of flowing slurry. The goal of that action is to either loosen the structure of densely packed grains or increase...

  19. GROUNDWATER FLOW MODEL CALIBRATION USING WATER LEVEL MEASUREMENTS AT SHORT INTERVALS

    Science.gov (United States)

    Groundwater flow models are usually calibrated with respect to water level measurements collected at intervals of several months or even years. Measurements of these kinds are not sensitive to sudden or short stress conditions, such as impact from stormwater drainage flow or flas...

  20. Viscous-flow calculations for KVLCC2 in deep and shallow water

    NARCIS (Netherlands)

    Toxopeus, S.L.

    2011-01-01

    In the SIMMAN 2008 workshop, the capability of CFD tools to predict the flow around manoeuvring ships has been investigated. It was decided to continue this effort but to extend the work to the flow around ships in shallow water. In this paper, CFD calculations for the KLVCC2 are presented. The aim

  1. One-dimensional model for heat transfer to a supercritical water flow in a tube

    NARCIS (Netherlands)

    Sallevelt, J.L.H.P.; Withag, J.A.M.; Bramer, E.A.; Brilman, D.W.F.; Brem, G.

    2012-01-01

    Heat transfer in water at supercritical pressures has been investigated numerically using a one-dimensional modeling approach. A 1D plug flow model has been developed in order to make fast predictions of the bulk-fluid temperature in a tubular flow. The chosen geometry is a vertical tube with an inn

  2. Angiographic coronary stenosis versus (15)O-water PET myocardial blood flow

    DEFF Research Database (Denmark)

    Thomassen, Anders; Braad, Poul-Erik; Johansen, Allan;

    2013-01-01

    Purpose: To examine which of stress myocardial flow (MBF) and coronary flow reserve (CFR) determined by (15)-water-PET (PET) correspond most closely with diameter stenosis assessed by quantitative coronary angiography (QCA). Methods: Twenty-three patients with a C40% QCA stenosis underwent baseline...

  3. Inequalities in the networks of virtual water flow

    Science.gov (United States)

    Carr, Joel; D'Odorico, Paolo; Laio, Francesco; Ridolfi, Luca; Seekell, David

    2012-08-01

    The globalization of water associated with the trade of food commodities [Hoekstra and Chapagain, 2008] has often been acclaimed as a means to save water, mitigate the effect of regional- and local-scale water scarcity, and meet the demand for food in overpopulated and water-poor countries [Allan, 1998]. However, there are negative implications for water use from globalization of trade. For instance, globalization disconnects populations from local sustainable freshwater use [Allan, 1998; D'Odorico et al., 2010]. This distance between societies and the resources on which they rely is a major obstacle to the emergence of behaviors that foster ecosystem stewardship [Chapin et al., 2009] through a responsible management of the environment. The globalization of water is also expected to reduce societal resilience to drought by decreasing the redundancy of freshwater resources, thereby limiting opportunities to meet human needs during periods of crisis [D'Odorico et al., 2010]. Overall, globalization enhances inequalities in the way different societies may have access to freshwater resources [Chapin et al., 2009]. In fact, only a few countries control most of the water that is virtually exchanged—through food trade—in the global market.

  4. Oil-water two-phase flow measurement with combined ultrasonic transducer and electrical sensors

    Science.gov (United States)

    Tan, Chao; Yuan, Ye; Dong, Xiaoxiao; Dong, Feng

    2016-12-01

    A combination of ultrasonic transducers operated in continuous mode and a conductance/capacitance sensor (UTCC) is proposed to estimate the individual flow velocities in oil-water two-phase flows. Based on the Doppler effect, the transducers measure the flow velocity and the conductance/capacitance sensor estimates the phase fraction. A set of theoretical correlations based on the boundary layer models of the oil-water two-phase flow was proposed to describe the velocity profile. The models were separately established for the dispersion flow and the separate flow. The superficial flow velocity of each phase is calculated with the velocity measured in the sampling volume of the ultrasonic transducer with the phase fraction through the velocity profile models. The measuring system of the UTCC was designed and experimentally verified on a multiphase flow loop. The results indicate that the proposed system and correlations estimate the overall flow velocity at an uncertainty of U J   =  0.038 m s-1, and the water superficial velocity at U Jw   =  0.026 m s-1, and oil superficial velocity at U Jo   =  0.034 m s-1. The influencing factors of uncertainty were analyzed.

  5. Slug flow transitions in horizontal gas/liquid two-phase flows. Dependence on channel height and system pressure for air/water and steam/water two-phase flows

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Hideo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1996-05-01

    The slug flow transitions and related phenomena for horizontal two-phase flows were studied for a better prediction of two-phase flows that typically appear during the reactor loss-of-coolant accidents (LOCAs). For better representation of the flow conditions experimentally, two large-scaled facility: TPTF for high-pressure steam/water two-phase flows and large duct test facility for air/water two-phase flows, were used. The visual observation of the flow using a video-probe was performed in the TPTF experiments for good understanding of the phenomena. The currently-used models and correlations based mostly on the small-scale low-pressure experiments were reviewed and improved based on these experimental results. The modified Taitel-Dukler model for prediction of transition into slug flow from wavy flow and the modified Steen-Wallis correlation for prediction of onset of liquid entrainment from the interfacial waves were obtained. An empirical correlation for the gas-liquid interfacial friction factor was obtained further for prediction of liquid levels at wavy flow. The region of slug flow regime that is generally under influences of the channel height and system pressure was predicted well when these models and correlations were applied together. (author). 90 refs.

  6. Hydrogeologic Setting and Ground-Water Flow in the Leetown Area, West Virginia

    Science.gov (United States)

    Kozar, Mark D.; Weary, David J.; Paybins, Katherine S.; Pierce, Herbert A.

    2007-01-01

    The Leetown Science Center is a research facility operated by the U.S. Geological Survey that occupies approximately 455-acres near Kearneysville, Jefferson County, West Virginia. Aquatic and fish research conducted at the Center requires adequate supplies of high-quality, cold ground water. Three large springs and three production wells currently (in 2006) supply water to the Center. The recent construction of a second research facility (National Center for Cool and Cold Water Aquaculture) operated by the U.S. Department of Agriculture and co-located on Center property has placed additional demands on available water resources in the area. A three-dimensional steady-state finite-difference ground-water flow model was developed to simulate ground-water flow in the Leetown area and was used to assess the availability of ground water to sustain current and anticipated future demands. The model also was developed to test a conceptual model of ground-water flow in the complex karst aquifer system in the Leetown area. Due to the complexity of the karst aquifer system, a multidisciplinary research study was required to define the hydrogeologic setting. Geologic mapping, surface- and borehole-geophysical surveys, stream base-flow surveys, and aquifer tests were conducted to provide the hydrogeologic data necessary to develop and calibrate the model. It would not have been possible to develop a numerical model of the study area without the intensive data collection and methods developments components of the larger, more comprehensive hydrogeologic investigation. Results of geologic mapping and surface-geophysical surveys verified the presence of several prominent thrust faults and identified additional faults and other complex geologic structures (including overturned anticlines and synclines) in the area. These geologic structures are known to control ground-water flow in the region. Results of this study indicate that cross-strike faults and fracture zones are major

  7. Modelling of Urban Water Flow - Coupling Surface and Pipe Flow. The State of The Eureka Projekt Risursim

    Science.gov (United States)

    Nieschulz, K.-P.; Risursim Project Group

    The challenge of serving the cities with efficient drainage networks and waste water systems is increasingly getting larger as the cities grow. Urban flooding, sewer over- flow and rainfall impact are high priority issues in most countries. The German and Norwegian EUREKA-Project RISURSIM (Risk management for urban drainage systems simulation and optimization) headed by ITWM focuses these problems. The overall objective is the development of an integrated planning and man- agement tool to allow cost effective management for urban drainage systems. The project consortium includes applied mathematics and water engineering research in- stitutes, municipal drainage works as well as insurance companies. Focussing on flooding events caused by surcharged sewer systems a dual drainage model has been developed to most accurately describe the hydraulic processes of flooded drainage systems taking in account the possible interactions between surface and surcharged sewer system. This dual drainage simulation model is computing water levels above ground and assessing possible damage costs. Hydraulic models for both, surface runoff and flooded surfaces, and sewer flow have been established. Surface flow is simulated in a 2-dimensional shallow water approach using GIS-based detailed physical surface data. Links to the hydraulic pipe flow model are stablished at all inlets of surface drainage (manholes, street inlets and private drain pipes) to the underground sewer system. These inlets are interpreted as possible sinks or sources in the mathematical model of both, surface and sewer flow simulation. In addition, the interaction between the public sewer system and private drains is taken into account in order to assess flooding of buildings or private ground via house drains. The status of the project is outlined; the structure of the being developed decision support system is presented.

  8. Water-level changes and directions of ground-water flow in the shallow aquifer, Fallon area, Churchill County, Nevada

    Science.gov (United States)

    Seiler, R.L.; Allander, K.K.

    1993-01-01

    The Truckee-Carson-Pyramid Lake Water Rights Settlement Act of 1990 directed the U.S. Fish and Wildlife Service to acquire water rights for wetland areas in the Carson Desert, Nevada. The public is concerned that htis acquisition of water rights and delivery of the water directly to wildlife areas would result in less recharge to the shallow ground water in the Fallon area and cause domestic wells to go dry. In January 1992, the U.S. Geological Survey, in cooperation with U.S. Fish and Wildlife Service, began a study of the shallow ground-water system in the Fallon area in Churchill County, Nevada. A network of 126 wells in the study area was monitored. Between January and November 1992, water levels in most wells declined, usually less than 2 feet. The maximum measured decline over this period was 2.68 feet in a well near Stillwater Marsh. Between April and July, however, water levels rose in irrigated areas, typically 1 to 2 feet. Newlands Project water deliveries to the study area began soon after the turn of the century. Since then, water levels have risen more than 15 feet across much of the study area. Water lost from unlined irrigtiaon canals caused the stage in Big Soda Lake to rise nearly 60 feet; ground-water levels near the lake have risen 30 to 40 feet. The depth to water in most irrigated areas is now less than 10 feet. The altitude of the water table ranges from 4.025 feet above sea level 11 miles west of Fallon to 3,865 feet in the Stillwater Marsh area. Ground water flows eastward and divides; some flow goes to the northeast toward the Carson Sink and Stillwater areas, and some goes southeastward to Carson Lake.

  9. Investigation on the liquid water droplet instability in a simulated flow channel of PEM fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Tae Hun; Kim, Bok Yung; Kim, Han Sang; Min, Kyoung Doug [Seoul National University, Seoul (Korea, Republic of)

    2008-05-15

    To investigate the characteristics of water droplets on the gas diffusion layer from both top-view and side-view of the flow channel, a rig test apparatus was designed and fabricated with prism attached plate. This experimental device was used to simulate the growth of a single liquid water droplet and its transport process with various air flow velocity and channel height. Not only dry condition but also fully humidified condition was also simulated by using a water absorbing sponge. The detachment height of the water droplet with dry and wet conditions was measured and analyzed. It was found that the droplet tends towards becoming unstable by decreased channel height, increased flow velocity or making a gas diffusion layer (GDL) dryer. Also, peculiar behavior of the water droplet in the channel was presented like attachment to hydrophilic wall or sudden breaking of droplet in case of fully hydrated condition. The simplified force balance model matches with experimental data as well

  10. EFFECT OF SANTA ROSA LAKE ON GROUND WATER FLOW TO THE PECOS RIVER, NEW MEXICO.

    Science.gov (United States)

    Risser, Dennis W.

    1985-01-01

    In 1980, Santa Rosa Dam began impounding water on the Pecos River about 7 miles (11 kilometers) north of Santa Rosa, New Mexico, to provide flood control and storage for irrigation. Santa Rosa Lake has caused changes in the ground water flow system, which may cause changes in the streamflow of the Pecos River that cannot be detected at the present streamflow-gaging stations, which are used to administer water rights along the Pecos River. The effect of the lake on streamflow was investigated using a three-dimensional ground water flow model. These simulations indicated that the net change in ground water flow to the river would be almost zero if the lake were maintained at its flood control pool for 90 days.

  11. Water pumping and analysis of flow in burrowing zoobenthos - a short overview

    DEFF Research Database (Denmark)

    Riisgård, Hans Ulrik; Larsen, Poul Scheel

    2005-01-01

    Burrowing animals maintain contact with the water above the sediment by pumping water through a tube system and therefore measurements of water pumping rate of burrowing animals is of crucial importance for the study of many processes both within and above the sea floor. This review deals...... with the measuring of water pumping and the analysis of flow generated by burrowing deposit- and filter-feeding zoobenthos in order to determine the type of pump and mechanisms involved, flow rate, pump pressure, and pumping power. The practical use of fluid mechanical principles is examined, and it is stressed...... that not only the pump pressure that a burrowing animal can apply is of interest for assessing the energy cost of pumping, but also the distribution of excess pressure along its burrow is of importance for assessing the seepage flow of oxygen-rich water into the sediment surrounding the burrow because...

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

    Energy Technology Data Exchange (ETDEWEB)

    K. Rehfeldt

    2004-10-08

    This report is an updated analysis of water-level data performed to provide the ''Saturated Zone Site-Scale Flow Model'' (BSC 2004 [DIRS 170037]) (referred to as the saturated zone (SZ) site-scale flow model or site-scale SZ flow model in this report) with the configuration of the potentiometric surface, target water-level data, and hydraulic gradients for calibration of groundwater flow models. This report also contains an expanded discussion of uncertainty in the potentiometric-surface map. The analysis of the potentiometric data presented in Revision 00 of this report (USGS 2001 [DIRS 154625]) provides the configuration of the potentiometric surface, target heads, and hydraulic gradients for the calibration of the SZ site-scale flow model (BSC 2004 [DIRS 170037]). Revision 01 of this report (USGS 2004 [DIRS 168473]) used updated water-level data for selected wells through the year 2000 as the basis for estimating water-level altitudes and the potentiometric surface in the SZ site-scale flow and transport model domain based on an alternative interpretation of perched water conditions. That revision developed computer files containing: Water-level data within the model area (DTN: GS010908312332.002); A table of known vertical head differences (DTN: GS010908312332.003); and A potentiometric-surface map (DTN: GS010608312332.001) using an alternative concept from that presented by USGS (2001 [DIRS 154625]) for the area north of Yucca Mountain. The updated water-level data presented in USGS (2004 [DIRS 168473]) include data obtained from the Nye County Early Warning Drilling Program (EWDP) Phases I and II and data from Borehole USW WT-24. This document is based on Revision 01 (USGS 2004 [DIRS 168473]) and expands the discussion of uncertainty in the potentiometric-surface map. This uncertainty assessment includes an analysis of the impact of more recent water-level data and the impact of adding data from the EWDP Phases III and IV wells. In

  13. Asymmetrical flow field-flow fractionation in the study of water-soluble macromolecules

    OpenAIRE

    Yohannes, Gebrenegus

    2007-01-01

    Asymmetrical flow field-flow fractionation (AsFlFFF) was constructed, and its applicability to industrial, biochemical, and pharmaceutical applications was studied. The effect of several parameters, such as pH, ionic strength, temperature and the reactants mixing ratios on the particle sizes, molar masses, and the formation of aggregates of macromolecules was determined by AsFlFFF. In the case of industrial application AsFlFFF proved to be a valuable tool in the characterization of the hydrod...

  14. Movement Protein of Cucumber Mosaic Virus Associates with Apoplastic Ascorbate Oxidase.

    Science.gov (United States)

    Kumari, Reenu; Kumar, Surender; Singh, Lakhmir; Hallan, Vipin

    Plant viral movement proteins facilitate virion movement mainly through interaction with a number of factors from the host. We report the association of a cell wall localized ascorbate oxidase (CsAO4) from Cucumis sativus with the movement protein (MP) of Cucumber mosaic virus (CMV). This was identified first in a yeast two-hybrid screen and validated by in vivo pull down and bimolecular fluorescence complementation (BiFC) assays. The BiFC assay showed localization of the bimolecular complexes of these proteins around the cell wall periphery as punctate spots. The expression of CsAO4 was induced during the initial infection period (up to 72 h) in CMV infected Nicotiana benthamiana plants. To functionally validate its role in viral spread, we analyzed the virus accumulation in CsAO4 overexpressing Arabidopsis thaliana and transiently silenced N. benthamiana plants (through a Tobacco rattle virus vector). Overexpression had no evident effect on virus accumulation in upper non-inoculated leaves of transgenic lines in comparison to WT plants at 7 days post inoculation (dpi). However, knockdown resulted in reduced CMV accumulation in systemic (non-inoculated) leaves of NbΔAO-pTRV2 silenced plants as compared to TRV inoculated control plants at 5 dpi (up to 1.3 fold difference). In addition, functional validation supported the importance of AO in plant development. These findings suggest that AO and viral MP interaction helps in early viral movement; however, it had no major effect on viral accumulation after 7 dpi. This study suggests that initial induction of expression of AO on virus infection and its association with viral MP helps both towards targeting of the MP to the apoplast and disrupting formation of functional AO dimers for spread of virus to nearby cells, reducing the redox defense of the plant during initial stages of infection.

  15. Virtual water flows in the international trade of agricultural products of China.

    Science.gov (United States)

    Zhang, Yu; Zhang, Jinhe; Tang, Guorong; Chen, Min; Wang, Lachun

    2016-07-01

    With the rapid development of the economy and population, water scarcity and poor water quality caused by water pollution have become increasingly severe in China. Virtual water trade is a useful tool to alleviate water shortage. This paper focuses on a comprehensive study of China's international virtual water flows from agricultural products trade and completes a diachronic analysis from 2001 to 2013. The results show that China was in trade surplus in relation to the virtual water trade of agricultural products. The exported virtual water amounted to 29.94billionm(3)/yr. while 155.55billionm(3)/yr. was embedded in imported products. The trend that China exported virtual water per year was on the decline while the imported was on a rising trend. Virtual water trade of China was highly concentrated. Not all of the exported products had comparative advantages in virtual water content. Imported products were excessively concentrated on water intensive agricultural products such as soya beans, cotton, and palm oil. The exported virtual water mainly flowed to the Republic of Korea, Hong Kong of China and Japan, while the imported mainly flowed from the United States of America, Brazil and Argentina. From the ethical point of view, the trade partners were classified into four types in terms of "net import" and "water abundance": mutual benefit countries, such as Australia and Canada; unilateral benefit countries, such as Mongolia and Norway; supported countries, such as Egypt and Singapore; and double pressure countries, such as India and Pakistan. Virtual water strategy refers to water resources, agricultural products and human beings. The findings are beneficial for innovating water resources management system, adjusting trade structure, ensuring food security in China, and promoting the construction of national ecological security system.

  16. Early Regimes of Water Capillary Flow in Slit Silica Nanochannels

    DEFF Research Database (Denmark)

    Oyarzua, Elton; Walther, Jens Honore; Mejia, Andres

    2015-01-01

    Molecular dynamics simulations are conducted to investigate the initial stages of spontaneous imbibitionof water in slit silica nanochannels surrounded by air. An analysis is performed for the effects of nanoscopicconfinement, initial conditions of liquid uptake and air pressurization...

  17. Global-scale analysis of river flow alterations due to water withdrawals and reservoirs

    Science.gov (United States)

    Döll, P.; Fiedler, K.; Zhang, J.

    2009-12-01

    Global-scale information on natural river flows and anthropogenic river flow alterations is required to identify areas where aqueous ecosystems are expected to be strongly degraded. Such information can support the identification of environmental flow guidelines and a sustainable water management that balances the water demands of humans and ecosystems. This study presents the first global assessment of the anthropogenic alteration of river flow regimes, in particular of flow variability, by water withdrawals and dams/reservoirs. Six ecologically relevant flow indicators were quantified using an improved version of the global water model WaterGAP. WaterGAP simulated, with a spatial resolution of 0.5 degree, river discharge as affected by human water withdrawals and dams around the year 2000, as well as naturalized discharge without this type of human interference. Compared to naturalized conditions, long-term average global discharge into oceans and internal sinks has decreased by 2.7% due to water withdrawals, and by 0.8% due to dams. Mainly due to irrigation, long-term average river discharge and statistical low flow Q90 (monthly river discharge that is exceeded in 9 out of 10 months) have decreased by more than 10% on one sixth and one quarter of the global land area (excluding Antarctica and Greenland), respectively. Q90 has increased significantly on only 5% of the land area, downstream of reservoirs. Due to both water withdrawals and reservoirs, seasonal flow amplitude has decreased significantly on one sixth of the land area, while interannual variability has increased on one quarter of the land area mainly due to irrigation. It has decreased on only 8% of the land area, in areas downstream of reservoirs where consumptive water use is low. The impact of reservoirs is likely underestimated by our study as small reservoirs are not taken into account. Areas most affected by anthropogenic river flow alterations are the Western and Central USA, Mexico, the

  18. Global-scale analysis of river flow alterations due to water withdrawals and reservoirs

    Directory of Open Access Journals (Sweden)

    P. Döll

    2009-12-01

    Full Text Available Global-scale information on natural river flows and anthropogenic river flow alterations is required to identify areas where aqueous ecosystems are expected to be strongly degraded. Such information can support the identification of environmental flow guidelines and a sustainable water management that balances the water demands of humans and ecosystems. This study presents the first global assessment of the anthropogenic alteration of river flow regimes, in particular of flow variability, by water withdrawals and dams/reservoirs. Six ecologically relevant flow indicators were quantified using an improved version of the global water model WaterGAP. WaterGAP simulated, with a spatial resolution of 0.5 degree, river discharge as affected by human water withdrawals and dams around the year 2000, as well as naturalized discharge without this type of human interference. Compared to naturalized conditions, long-term average global discharge into oceans and internal sinks has decreased by 2.7% due to water withdrawals, and by 0.8% due to dams. Mainly due to irrigation, long-term average river discharge and statistical low flow Q90 (monthly river discharge that is exceeded in 9 out of 10 months have decreased by more than 10% on one sixth and one quarter of the global land area (excluding Antarctica and Greenland, respectively. Q90 has increased significantly on only 5% of the land area, downstream of reservoirs. Due to both water withdrawals and reservoirs, seasonal flow amplitude has decreased significantly on one sixth of the land area, while interannual variability has increased on one quarter of the land area mainly due to irrigation. It has decreased on only 8% of the land area, in areas downstream of reservoirs where consumptive water use is low. The impact of reservoirs is likely underestimated by our study as small reservoirs are not taken into account. Areas most affected by anthropogenic river flow

  19. Characteristics of flow field and water concentration in a horizontal deadleg

    Energy Technology Data Exchange (ETDEWEB)

    Habib, M.A.; Badr, H.M.; Said, S.A.M.; Mokheimer, E.M.A.; Hussaini, I. [King Fahd University of Petroleum and Minerals, Mechanical Engineering Department, Dhahran (Saudi Arabia); Al-Sanaa, M. [Saudi Aramco (Saudi Arabia)

    2005-02-01

    Deadlegs are defined as the inactive portion of the pipe where the flow is stagnant. Corrosion in deadlegs occurs as a result of water separation due to the very low flow velocity. The present work provides an investigation of the effect of deadleg geometry and average flow velocity on flow field and oil/water separation in deadlegs. The investigation is based on the solution of the mass and momentum conservation equations of an oil/water mixture together with the volume fraction equation for the secondary phase. A fluid flow model based on the time-averaged governing equations of 3-D turbulent flow has been developed. An algebraic slip mixture model is utilized for the calculation of the two immiscible fluids (water and crude oil). The model solves the continuity and momentum equations for the mixture, and the volume fraction equation for the secondary phase utilizing an algebraic expression for the relative velocity. Flow visualization experiments were conducted in order to validate the numerical procedure. Good agreement was obtained between the calculated and measured flow patterns. Results are obtained for different lengths of the deadleg. The considered fluid mixture contains 90% oil and 10% water (by volume). The inlet flow velocity ranges from 0.2 to 10 m/s and the deadleg length to diameter ratio (L/D) ranges from 1 to 10. The results showed that the size of the stagnant fluid region increases with the increase of L/D and decreases with the increase of inlet velocity. The results also indicated that the water volumetric concentration increases with the increase of L/D and influenced by the deadleg geometry. (orig.)

  20. Fragmented Flows: Water Supply in Los Angeles County

    Science.gov (United States)

    Pincetl, Stephanie; Porse, Erik; Cheng, Deborah

    2016-08-01

    In the Los Angeles metropolitan region, nearly 100 public and private entities are formally involved in the management and distribution of potable water—a legacy rooted in fragmented urban growth in the area and late 19th century convictions about local control of services. Yet, while policy debates focus on new forms of infrastructure, restructured pricing mechanisms, and other technical fixes, the complex institutional architecture of the present system has received little attention. In this paper, we trace the development of this system, describe its interconnections and disjunctures, and demonstrate the invisibility of water infrastructure in LA in multiple ways—through mapping, statistical analysis, and historical texts. Perverse blessings of past water abundance led to a complex, but less than resilient, system with users accustomed to cheap, easily accessible water. We describe the lack of transparency and accountability in the current system, as well as its shortcomings in building needed new infrastructure and instituting new water rate structures. Adapting to increasing water scarcity and likely droughts must include addressing the architecture of water management.

  1. Numerical simulation of oil-water two-phase flow in horizontal pipes

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Michelly Martuchele; Ramirez, Ramiro Gustavo [Federal University of Itajuba (UNIFEI), MG (Brazil)], E-mail: ramirez@unifei.edu.br

    2010-07-01

    The numerical simulation of two phase flow through the CFD techniques have become of great interest due to the complexity of this type of flow. The present work aims to simulate the oil-water two-phase flow in horizontal pipes for stratification analysis of the mixture. In numerical simulations, incompressible flow, isothermal, steady state and laminar flow were considered. Numerical analysis of flow stratification was carried out for horizontal straight and curved pipe. FLUENT was the commercial software employed in the simulation. Three-dimensional mesh generated by ICEM-CFD program was used for numerical simulation. The numerical analysis flow pattern was carried out employing the Eulerian model, considering the drag and lift interphase forces. The simulation results for the horizontal straight pipe were qualitatively validated with experimental data obtained in the Laboratory of Phase Separation of UNIFEI. (author)

  2. Preferential flow, connectivity and the principle of "minimum time to equilibrium": a new perspective on environmental water flow

    Science.gov (United States)

    Zehe, E.; Blume, T.; Bloeschl, G.

    2008-12-01

    Preferential/rapid flow and transport is known as one key process in soil hydrology for more than 20 years. It seems to be rather the rule, than the exception. It occurs in soils, in surface rills and river networks. If connective preferential are present at any scale, they crucially control water flow and solute transport. Why? Is there an underlying principle? If energy is conserved a system follows Fermat's principle of minimum action i.e. it follows the trajectory that minimise the integral of the total energy/ La Grangian over time. Hydrological systems are, however, non-conservative as surface and subsurface water flows dissipate energy. From thermodynamics it is well known that natural processes minimize the free energy of the system. For hydrological systems we suggest, therefore, that flow in a catchment arranges in such a way that time to a minimum of free energy becomes minimal for a given rainfall input (disturbance) and under given constraints. Free energy in a soil is determined by potential energy and capillary energy. The pore size distribution of the soil, soil structures, depth to groundwater and most important vegetation make up the constraints. The pore size distribution determines whether potential energy or capillarity dominates the free energy of the soil system. The first term is minimal when the pore space is completely de-saturated the latter becomes minimal at soil saturation. Hence, the soil determines a) the amount of excess (gravity) water that has to be exported from the soil to reach a minimum state of free energy and b) whether redistribution or groundwater recharge is more efficient to reach that equilibrium. On the other hand, the pore size distribution of the soil and the connectivity of preferential pathways (root channels, worm holes and cracks) determine flow velocities and the redistribution of water within the pore space. As water flow and ground water recharge are fast in sandy soils and capillary energy is of minor

  3. OIL-WATER TWO-PHASE FLOW INSIDE T-JUNCTION

    Institute of Scientific and Technical Information of China (English)

    WANG Li-yang; WU Ying-xiang; ZHENG Zhi-chu; GUO Jun; ZHANG Jun; TANG Chi

    2008-01-01

    The oil / water two-phase flow inside T-junctions was numerically simulated with a 3-D two-fluid model, and the turbulence was described using the mixture model. Some experiments of oil / water flow inside a single T-junction were conducted in the laboratory. The results show that the separating performance of T-junction largely depends on the inlet volumetric fraction and flow patterns. A reasonable agreement is reached between the numerical simulation and the experiments for both the oil fraction distribution and the separation efficiency.

  4. Large eddy simulation of water flow over series of dunes

    Directory of Open Access Journals (Sweden)

    Jun LU

    2011-12-01

    Full Text Available Large eddy simulation was used to investigate the spatial development of open channel flow over a series of dunes. The three-dimensional filtered Navier-Stokes (N-S equations were numerically solved with the fractional-step method in sigma coordinates. The subgrid-scale turbulent stress was modeled with a dynamic coherent eddy viscosity model proposed by the authors. The computed velocity profiles are in good agreement with the available experimental results. The mean velocity and the turbulent Reynolds stress affected by a series of dune-shaped structures were compared and analyzed. The variation of turbulence statistics along the flow direction affected by the wavy bottom roughness has been studied. The turbulent boundary layer in a complex geographic environment can be simulated well with the proposed large eddy simulation (LES model.

  5. Global-scale analysis of river flow alterations due to water withdrawals and reservoirs

    Directory of Open Access Journals (Sweden)

    P. Döll

    2009-07-01

    Full Text Available Global-scale information on natural river flows and anthropogenic river flow alterations is required to identify areas where aqueous ecosystems are expected to be strongly degraded. Such information can support the identification of environmental flow guidelines and a sustainable water management that balances the water demands of humans and ecosystems. This study presents the first global assessment of the anthropogenic alteration of river flow regimes by water withdrawals and dams, focusing in particular on the change of flow variability. Six ecologically relevant flow indicators were quantified using an improved version of the global water model WaterGAP. WaterGAP simulated, with a spatial resolution of 0.5 degree, river discharge as affected by human water withdrawals and dams, as well as naturalized discharge without this type of human interference. Mainly due to irrigation, long-term average river discharge and statistical low flow Q90 (monthly river discharge that is exceeded in 9 out of 10 months have decreased by more than 10% on one sixth and one quarter of the global land area (excluding Antarctica and Greenland, respectively. Q90 has increased significantly on only 5% of the land area, downstream of reservoirs. Due to both water withdrawals and dams, seasonal flow amplitude has decreased significantly on one sixth of the land area, while interannual variability has increased on one quarter of the land area mainly due to irrigation. It has decreased on only 8% of the land area, in areas with little consumptive water use that are downstream of dams. Areas most affected by anthropogenic river flow alterations are the western and central USA, Mexico, the western coast of South America, the Mediterranean rim, Southern Africa, the semi-arid and arid countries of the Near East and Western Asia, Pakistan and India, Northern China and the Australian Murray-Darling Basin, as well as some Arctic rivers. Due

  6. Impacts of impervious cover, water withdrawals, and climate change on river flows in the conterminous US

    Directory of Open Access Journals (Sweden)

    P. V. Caldwell

    2012-08-01

    Full Text Available Rivers are essential to aquatic ecosystem and societal sustainability, but are increasingly impacted by water withdrawals, land-use change, and climate change. The relative and cumulative effects of these stressors on continental river flows are relatively unknown. In this study, we used an integrated water balance and flow routing model to evaluate the impacts of impervious cover and water withdrawal on river flow across the conterminous US at the 8-digit Hydrologic Unit Code (HUC watershed scale. We then estimated the impacts of projected change in withdrawals, impervious cover, and climate under the B1 "Low" and A2 "High" emission scenarios on river flows by 2060. Our results suggest that compared to no impervious cover, 2010 levels of impervious cover increased river flows by 9.9% on average with larger impacts in and downstream of major metropolitan areas. In contrast, compared to no water withdrawals, 2005 withdrawals decreased river flows by 1.4% on average with larger impacts in heavily irrigated arid regions of Western US. By 2060, impacts of climate change were predicted to overwhelm the potential gain in river flow due to future changes in impervious cover and add to the potential reduction in river flows from withdrawals, decreasing mean annual river flows from 2010 levels by 16% on average. However, increases in impervious cover by 2060 may offset the impact of climate change during the growing season in some watersheds. Large water withdrawals will aggravate the predicted impact of climate change on river flows, particularly in the Western US. Predicted ecohydrological impacts of land cover, water withdrawal, and climate change will likely include alteration of the terrestrial water balance, stream channel habitat, riparian and aquatic community structure in snow-dominated basins, and fish and mussel extirpations in heavily impacted watersheds. These changes may also require new infrastructure to support increasing anthropogenic

  7. Multiregional input-output model for the evaluation of Spanish water flows.

    Science.gov (United States)

    Cazcarro, Ignacio; Duarte, Rosa; Sánchez Chóliz, Julio

    2013-01-01

    We construct a multiregional input-output model for Spain, in order to evaluate the pressures on the water resources, virtual water flows, and water footprints of the regions, and the water impact of trade relationships within Spain and abroad. The study is framed with those interregional input-output models constructed to study water flows and impacts of regions in China, Australia, Mexico, or the UK. To build our database, we reconcile regional IO tables, national and regional accountancy of Spain, trade and water data. Results show an important imbalance between origin of water resources and final destination, with significant water pressures in the South, Mediterranean, and some central regions. The most populated and dynamic regions of Madrid and Barcelona are important drivers of water consumption in Spain. Main virtual water exporters are the South and Central agrarian regions: Andalusia, Castile-La Mancha, Castile-Leon, Aragon, and Extremadura, while the main virtual water importers are the industrialized regions of Madrid, Basque country, and the Mediterranean coast. The paper shows the different location of direct and indirect consumers of water in Spain and how the economic trade and consumption pattern of certain areas has significant impacts on the availability of water resources in other different and often drier regions.

  8. Hydrology and simulation of ground-water flow in Kamas Valley, Summit County, Utah

    Science.gov (United States)

    Brooks, L.E.; Stolp, B.J.; Spangler, L.E.

    2003-01-01

    Kamas Valley, Utah, is located about 50 miles east of Salt Lake City and is undergoing residential development. The increasing number of wells and septic systems raised concerns of water managers and prompted this hydrologic study. About 350,000 acre-feet per year of surface water flows through Kamas Valley in the Weber River, Beaver Creek, and Provo River, which originate in the Uinta Mountains east of the study area. The ground-water system in this area consists of water in unconsolidated deposits and consolidated rock; water budgets indicate very little interaction between consolidated rock and unconsolidated deposits. Most recharge to consolidated rock occurs at higher altitudes in the mountains and discharges to streams and springs upgradient of Kamas Valley. About 38,000 acre-feet per year of water flows through the unconsolidated deposits in Kamas Valley. Most recharge is from irrigation and seepage from major streams; most discharge is to Beaver Creek in the middle part of the valley. Long-term water-level fluctuations range from about 3 to 17 feet. Seasonal fluctuations exceed 50 feet. Transmissivity varies over four orders of magnitude in both the unconsolidated deposits and consolidated rock and is typically 1,000 to 10,000 feet squared per day in unconsolidated deposits and 100 feet squared per day in consolidated rock as determined from specific capacity. Water samples collected from wells, streams, and springs had nitrate plus nitrite concentrations (as N) substantially less than 10 mg/L. Total and fecal coliform bacteria were detected in some surface-water samples and probably originate from livestock. Septic systems do not appear to be degrading water quality. A numerical ground-water flow model developed to test the conceptual understanding of the ground-water system adequately simulates water levels and flow in the unconsolidated deposits. Analyses of model fit and sensitivity were used to refine the conceptual and numerical models.

  9. Evaluation of 2D shallow-water model for spillway flow with a complex geometry

    Science.gov (United States)

    Although the two-dimensional (2D) shallow water model is formulated based on several assumptions such as hydrostatic pressure distribution and vertical velocity is negligible, as a simple alternative to the complex 3D model, it has been used to compute water flows in which these assumptions may be ...

  10. Tracing ground water input to base flow using sulfate (S, O) isotopes.

    Science.gov (United States)

    Gu, Ailiang; Gray, Floyd; Eastoe, Christopher J; Norman, Laura M; Duarte, Oscar; Long, Austin

    2008-01-01

    Sulfate (S and O) isotopes used in conjunction with sulfate concentration provide a tracer for ground water contributions to base flow. They are particularly useful in areas where rock sources of contrasting S isotope character are juxtaposed, where water chemistry or H and O isotopes fail to distinguish water sources, and in arid areas where rain water contributions to base flow are minimal. Sonoita Creek basin in southern Arizona, where evaporite and igneous sources of sulfur are commonly juxtaposed, serves as an example. Base flow in Sonoita Creek is a mixture of three ground water sources: A, basin ground water with sulfate resembling that from Permian evaporite; B, ground water from the Patagonia Mountains; and C, ground water associated with Temporal Gulch. B and C contain sulfate like that of acid rock drainage in the region but differ in sulfate content. Source A contributes 50% to 70%, with the remainder equally divided between B and C during the base flow seasons. The proportion of B generally increases downstream. The proportion of A is greatest under drought conditions.

  11. Interrelationships of petiole air canal architecture, water depth and convective air flow in Nymphaea odorata (Nymphaeaceae)

    Science.gov (United States)

    Premise of the study--Nymphaea odorata grows in water up to 2 m deep, producing fewer, larger leaves in deeper water. This species has a convective flow system that moves gases from younger leaves through submerged parts to older leaves, aerating submerged parts. Petiole air canals are in the conv...

  12. Heterogeneous water flow and pesticide transport in cultivated sandy soils : description of model concepts

    NARCIS (Netherlands)

    Leistra, M.; Boesten, J.J.T.I.

    2011-01-01

    There is ample experimental evidence that complications in water flow and pesticide transport can occur in cultivated humic-sandy and loamy-sandy soils. As a result, pesticide leaching to groundwater and water courses can be higher than expected. We made an inventory of mechanistic/deterministic mod

  13. The influence of water flow (reversal) on bond strength development in young masonry

    NARCIS (Netherlands)

    Groot, C.; Larbi, J.

    1999-01-01

    Water loss from the fresh mortar is believed to be related to mortar-brick bond strength development in masonry. Recent research on mortar-brick bond has shown that, particularly, effects of water flow on the composition and the hydration conditions of the mortar-brick interface have to be taken int

  14. Tracing ground water input to base flow using sulfate (S, O) isotopes

    Science.gov (United States)

    Gu, A.; Gray, F.; Eastoe, C.J.; Norman, L.M.; Duarte, O.; Long, A.

    2008-01-01

    Sulfate (S and O) isotopes used in conjunction with sulfate concentration provide a tracer for ground water contributions to base flow. They are particularly useful in areas where rock sources of contrasting S isotope character are juxtaposed, where water chemistry or H and O isotopes fail to distinguish water sources, and in arid areas where rain water contributions to base flow are minimal. Sonoita Creek basin in southern Arizona, where evaporite and igneous sources of sulfur are commonly juxtaposed, serves as an example. Base flow in Sonoita Creek is a mixture of three ground water sources: A, basin ground water with sulfate resembling that from Permian evaporite; B, ground water from the Patagonia Mountains; and C, ground water associated with Temporal Gulch. B and C contain sulfate like that of acid rock drainage in the region but differ in sulfate content. Source A contributes 50% to 70%, with the remainder equally divided between B and C during the base flow seasons. The proportion of B generally increases downstream. The proportion of A is greatest under drought conditions.

  15. CFD Study of Fluid Flow in an All-glass Evacuated Tube Solar Water Heater

    DEFF Research Database (Denmark)

    Ai, Ning; Fan, Jianhua; Li, Yumin

    2008-01-01

    Abstract: The all-glass evacuated tube solar water heater is one of the most widely used solar thermal technologies. The aim of the paper is to investigate fluid flow in the solar water heater by means of computational fluid dynamics (CFD). The investigation was carried out with a focus...

  16. Amsterdam as a Sustainable European Metropolis: Integration of Water, Energy and Material Flows

    NARCIS (Netherlands)

    Van Der Hoek, J.P.; Struker, A.; Danschutter, J.E.M.

    2013-01-01

    Amsterdam has the ambition to develop as a competitive and sustainable European metropolis. The flows of energy, water and resources within the urban environment have a large potential to contribute to this ambition. The overall mass balances of phosphate, food, water, energy and material imports in

  17. Water pumping and analysis of flow in burrowing zoobenthos - a short overview

    DEFF Research Database (Denmark)

    Riisgård, H. U.; Larsen, Poul Scheel

    2002-01-01

    Measurement of water pumping rates of burrowing animals is of crucial importance for the study of many processes both within and above the sea floor. This short review deals with water pumping and analysis of flow, including available techniques and bio-fluid mechanical theory, in burrowing deposit...

  18. Apoplastic reactive oxygen species transiently decrease auxin signaling and cause stress-induced morphogenic response in Arabidopsis.

    Science.gov (United States)

    Blomster, Tiina; Salojärvi, Jarkko; Sipari, Nina; Brosché, Mikael; Ahlfors, Reetta; Keinänen, Markku; Overmyer, Kirk; Kangasjärvi, Jaakko

    2011-12-01

    Reactive oxygen species (ROS) are ubiquitous signaling molecules in plant stress and development. To gain further insight into the plant transcriptional response to apoplastic ROS, the phytotoxic atmospheric pollutant ozone was used as a model ROS inducer in Arabidopsis (Arabidopsis thaliana) and gene expression was analyzed with microarrays. In contrast to the increase in signaling via the stress hormones salicylic acid, abscisic acid, jasmonic acid (JA), and ethylene, ROS treatment caused auxin signaling to be transiently suppressed, which was confirmed with a DR5-uidA auxin reporter construct. Transcriptomic data revealed that various aspects of auxin homeostasis and signaling were modified by apoplastic ROS. Furthermore, a detailed analysis of auxin signaling showed that transcripts of several auxin receptors and Auxin/Indole-3-Acetic Acid (Aux/IAA) transcriptional repressors were reduced in response to apoplastic ROS. The ROS-derived changes in the expression of auxin signaling genes partially overlapped with abiotic stress, pathogen responses, and salicylic acid signaling. Several mechanisms known to suppress auxin signaling during biotic stress were excluded, indicating that ROS regulated auxin responses via a novel mechanism. Using mutants defective in various auxin (axr1, nit1, aux1, tir1 afb2, iaa28-1, iaa28-2) and JA (axr1, coi1-16) responses, ROS-induced cell death was found to be regulated by JA but not by auxin. Chronic ROS treatment resulted in altered leaf morphology, a stress response known as "stress-induced morphogenic response." Altered leaf shape of tir1 afb2 suggests that auxin was a negative regulator of stress-induced morphogenic response in the rosette.

  19. GSFLOW - Coupled Ground-Water and Surface-Water Flow Model Based on the Integration of the Precipitation-Runoff Modeling System (PRMS) and the Modular Ground-Water Flow Model (MODFLOW-2005)

    Science.gov (United States)

    Markstrom, Steven L.; Niswonger, Richard G.; Regan, R. Steven; Prudic, David E.; Barlow, Paul M.

    2008-01-01

    The need to assess the effects of variability in climate, biota, geology, and human activities on water availability and flow requires the development of models that couple two or more components of the hydrologic cycle. An integrated hydrologic model called GSFLOW (Ground-water and Surface-water FLOW) was developed to simulate coupled ground-water and surface-water resources. The new model is based on the integration of the U.S. Geological Survey Precipitation-Runoff Modeling System (PRMS) and the U.S. Geological Survey Modular Ground-Water Flow Model (MODFLOW). Additional model components were developed, and existing components were modified, to facilitate integration of the models. Methods were developed to route flow among the PRMS Hydrologic Response Units (HRUs) and between the HRUs and the MODFLOW finite-difference cells. This report describes the organization, concepts, design, and mathematical formulation of all GSFLOW model components. An important aspect of the integrated model design is its ability to conserve water mass and to provide comprehensive water budgets for a location of interest. This report includes descriptions of how water budgets are calculated for the integrated model and for individual model components. GSFLOW provides a robust modeling system for simulating flow through the hydrologic cycle, while allowing for future enhancements to incorporate other simulation techniques.

  20. Bifurcations of a creeping air-water flow in a conical container

    Science.gov (United States)

    Balci, Adnan; Brøns, Morten; Herrada, Miguel A.; Shtern, Vladimir N.

    2016-10-01

    This numerical study describes the eddy emergence and transformations in a slow steady axisymmetric air-water flow, driven by a rotating top disk in a vertical conical container. As water height Hw and cone half-angle β vary, numerous flow metamorphoses occur. They are investigated for β =30°, 45°, and 60°. For small Hw, the air flow is multi-cellular with clockwise meridional circulation near the disk. The air flow becomes one cellular as Hw exceeds a threshold depending on β . For all β , the water flow has an unbounded number of eddies whose size and strength diminish as the cone apex is approached. As the water level becomes close to the disk, the outmost water eddy with clockwise meridional circulation expands, reaches the interface, and induces a thin layer with anticlockwise circulation in the air. Then this layer expands and occupies the entire air domain. The physical reasons for the flow transformations are provided. The results are of fundamental interest and can be relevant for aerial bioreactors.

  1. Study on an Undershot Cross-Flow Water Turbine with Straight Blades

    Directory of Open Access Journals (Sweden)

    Yasuyuki Nishi

    2015-01-01

    Full Text Available Small-scale hydroelectric power generation has recently attracted considerable attention. The authors previously proposed an undershot cross-flow water turbine with a very low head suitable for application to open channels. The water turbine was of a cross-flow type and could be used in open channels with the undershot method, remarkably simplifying its design by eliminating guide vanes and the casing. The water turbine was fitted with curved blades (such as the runners of a typical cross-flow water turbine installed in tube channels. However, there was ambiguity as to how the blades’ shape influenced the turbine’s performance and flow field. To resolve this issue, the present study applies straight blades to an undershot cross-flow water turbine and examines the performance and flow field via experiments and numerical analyses. Results reveal that the output power and the turbine efficiency of the Straight Blades runner were greater than those of the Curved Blades runner regardless of the rotational speed. Compared with the Curved Blades runner, the output power and the turbine efficiency of the Straight Blades runner were improved by about 31.7% and about 67.1%, respectively.

  2. Integrated water and sediment flow simulation and forecasting models for river reaches

    Science.gov (United States)

    Choudhury, Parthasarathi; Sil, Briti Sundar

    2010-05-01

    SummaryIn the present study integrated water and sediment flow simulation and forecasting models for a river reach have been developed. The new models combine Muskingum model and the sediment rating model leading to integrated water discharge-sediment concentration model ( WSCM) and water discharge-sediment discharge model ( WSDM) for a reach. The models depict coherence in water discharge and sediment load variations at a site; incorporate two hydrologic variables, water discharge and sediment load for the gauge sites and represent revised forms of the basic Muskingum model. The models can be recast into forecasting form useful for obtaining downstream water and sediment flow forecasts Δt'=2kx time unit ahead. During calibration the models can select a commensurate inflow-outflow set depending on upstream and the downstream relative sediment discharge characteristics for a reach. The models can be used for developing Muskingum model for river reaches having no water discharge records. With forecasting capabilities the present models are useful in the real time management of sediment related pollution hazards in water courses. The study indicates that a single model could be used to describe both water and sediment flow in river reaches. The proposed model formulations are demonstrated for simulating and forecasting sediment concentration, sediment discharge and water discharge in the Mississippi River Basin, USA. Model parameters are estimated using non-dominated sorting Genetic Algorithm II (NSGA-II). Comparison of models performances with reported works show better performances by the present models.

  3. Simulation of the solidification in a channel of a water-cooled glass flow

    Directory of Open Access Journals (Sweden)

    G. E. Ovando Chacon

    2014-12-01

    Full Text Available A computer simulation study of a laminar steady-state glass flow that exits from a channel cooled with water is reported. The simulations are carried out in a two-dimensional, Cartesian channel with a backward-facing step for three different angles of the step and different glass outflow velocities. We studied the interaction of the fluid dynamics, phase change and thermal behavior of the glass flow due to the heat that transfers to the cooling water through the wall of the channel. The temperature, streamline, phase change and pressure fields are obtained and analyzed for the glass flow. Moreover, the temperature increments of the cooling water are characterized. It is shown that, by reducing the glass outflow velocity, the solidification is enhanced; meanwhile, an increase of the step angle also improves the solidification of the glass flow.

  4. Modeling Flow Rate to Estimate Hydraulic Conductivity in a Parabolic Ceramic Water Filter

    Directory of Open Access Journals (Sweden)

    Ileana Wald

    2012-01-01

    Full Text Available In this project we model volumetric flow rate through a parabolic ceramic water filter (CWF to determine how quickly it can process water while still improving its quality. The volumetric flow rate is dependent upon the pore size of the filter, the surface area, and the height of water in the filter (hydraulic head. We derive differential equations governing this flow from the conservation of mass principle and Darcy's Law and find the flow rate with respect to time. We then use methods of calculus to find optimal specifications for the filter. This work is related to the research conducted in Dr. James R. Mihelcic's Civil and Environmental Engineering Lab at USF.

  5. Mode pattern of internal flow in a water droplet on a vibrating hydrophobic surface.

    Science.gov (United States)

    Kim, Hun; Lim, Hee-Chang

    2015-06-01

    The objective of this study is to understand the mode pattern of the internal flow in a water droplet placed on a hydrophobic surface that periodically and vertically vibrates. As a result, a water droplet on a vibrating hydrophobic surface has a typical shape that depends on each resonance mode, and, additionally, we observed a diversified lobe size and internal flows in the water droplet. The size of each lobe at the resonance frequency was relatively greater than that at the neighboring frequencies, and the internal flow of the nth order mode was also observed in the flow visualization. In general, large symmetrical flow streams were generated along the vertical axis in each mode, with a large circulating movement from the bottom to the top, and then to the triple contact line along the droplet surface. In contrast, modes 2 and 4 generated a Y-shaped flow pattern, in which the flow moved to the node point in the lower part of the droplet, but modes 6 and 8 had similar patterns, with only a little difference. In addition, as a result of the PIV measurement, while the flow velocity of mode 4 was faster than that of model 2, those of modes 6 and 8 were almost similar.

  6. Numerical investigation of cavitating flow behind the cone of a poppet valve in water hydraulic system

    Institute of Scientific and Technical Information of China (English)

    高红; 傅新; 杨华勇; TSUKIJITetsuhiro

    2002-01-01

    Computational Fluid Dynarmics(CFD) simulations of cavitating flow throuth water hydraulic poppet valves were performed using advanced RNG κ-epsilon turbulence model. The flow was turbulent, incom-pressible and unsteady, for Reynolds nurnbers greater than 43 000.The working fluid was water, and the structure of the valve was simplified as a two dimensionl axisynmmetric gecomtrical model. Flow Field vlsual-ization was numerically achieved. The effects of inlet velocity, outlet pressure, opening size as wall as popet angle on cavitation intensity in the poppet valve were numerically investigated. Experimentall flow visualization was coonducted to capture cavitation images near the orifice in the poppet valve with 30° poppet angle using high speed video camera.The binary cavitafing flow field distrilxrdon obtalned frcra digital processing of the original cavitation image showed a gtxxt agreement with the ntmaerieal result

  7. Unsteady mixed flows in non uniform closed water pipes: a Full Kinetic Appraoch

    CERN Document Server

    Bourdarias, Christian; Gerbi, Stéphane

    2011-01-01

    We recall the \\PFS} model constructed for the modeling of unsteady mixed flows in closed water pipes where transition points between the free surface and pressurized flow are treated as a free boundary associated to a discontinuity of the gradient of pressure. Then we present a numerical kinetic scheme for the computations of unsteady mixed flows in closed water pipes. This kinetic method that we call FKA for "Full Kinetic Approach" is an easy and mathematically elegant way to deal with multiple transition points when the changes of state between free surface and pressurized flow occur. We use two approaches namely the "ghost waves approach" and the "Full Kinetic Approach" to treat these transition points. We show that this kinetic numerical scheme has the following properties: it is wet area conservative, under a CFL condition it preserves the wet area positive, it treats "naturally" the drying and flooding area and most of all it preserves every stationary flow. Finally numerical experiment versus laborator...

  8. Interfacial wave behavior in oil-water channel flows: Prospects for a general understanding

    Energy Technology Data Exchange (ETDEWEB)

    McCready, M.J.; Uphold, D.D.; Gifford, K.A. [Univ. of Notre Dame, IN (United States)

    1997-12-31

    Oil-water pressure driven channel flow is examined as a model for general two-layer flows where interfacial disturbances are important. The goal is to develop sufficient understanding of this system so that the utility and limitations of linear and nonlinear theories can be known a priori. Experiments show that sometimes linear stability is useful at predicting the steady or dominant evolving waves. However in other situations there is no agreement between the linearly fastest growing wave and the spectral peak. An interesting preliminary result is that the bifurcation to interfacial waves is supercritical for all conditions that were studied for an oil-water channel flow, gas-liquid channel flow and two-liquid Couette flow. However, three different mechanisms are dominant for each of these three situations.

  9. Continuum Navier-Stokes modelling of water flow past fullerene molecules

    Science.gov (United States)

    Walther, J. H.; Popadic, A.; Koumoutsakos, P.; Praprotnik, M.

    2015-11-01

    We present continuum simulations of water flow past fullerene molecules. The governing Navier-Stokes equations are complemented with the Navier slip boundary condition with a slip length that is extracted from related molecular dynamics simulations. We find that several quantities of interest as computed by the present model are in good agreement with results from atomistic and atomistic-continuum simulations at a fraction of the computational cost. We simulate the flow past a single fullerene and an array of fullerenes and demonstrate that such nanoscale flows can be computed efficiently by continuum flow solvers, allowing for investigations into spatiotemporal scales inaccessible to atomistic simulations.

  10. Application of Tank Model for Predicting Water Balance and Flow Discharge Components of Cisadane Upper Catchment

    Directory of Open Access Journals (Sweden)

    Nana Mulyana Arifjaya

    2012-01-01

    Full Text Available The concept of hydrological tank model was well described into four compartments (tanks. The first tank (tank A comprised of one vertical (qA0 and two lateral (qA1 and qA2 water flow components and tank B comprised of one vertical (qB0 and one lateral (qB1 water flow components. Tank C comprised of one vertical (qC0 and one lateral (qC1 water flow components, whereas tank D comprised of one lateral water flow component (qD1.  These vertical water flows would also contribute to the depletion of water flow in the related tanks but would replenish tanks in the deeper layers. It was assumed that at all lateral water flow components would finally accumulate in one stream, summing-up of the lateral water flow, much or less, should be equal to the water discharge (Qo at specified time concerns. Tank A received precipitation (R and evapo-transpiration (ET which was its gradientof (R-ET over time would become the driving force for the changes of water stored in the soil profiles and thosewater flows leaving the soil layer.  Thus tank model could describe th vertical and horizontal water flow withinthe watershed. The research site was Cisadane Upper Catchment, located at Pasir Buncir Village of CaringinSub-District within the Regency of Bogor in West Java Province.  The elevations ranged 512 –2,235 m above sealevel, with a total drainage area of 1,811.5 ha and total length of main stream of 14,340.7 m.  The land cover wasdominated by  forest  with a total of 1,044.6 ha (57.67%,  upland agriculture with a total of 477.96 ha (26.38%,mixed garden with a total of 92.85 ha(5.13% and semitechnical irigated rice field with a total of 196.09 ha (10,8%.  The soil was classified as hydraquent (96.6% and distropept (3.4%.  Based on the calibration of tank model application in the study area, the resulting coefficient of determination (R2 was 0.72 with model efficiency (NSEof= 0.75, thus tank model could well illustrate the water flow distribution of

  11. Effect of Flow Rate of Side-Type Orifice Intake on Withdrawn Water Temperature

    Directory of Open Access Journals (Sweden)

    Xueping Gao

    2014-01-01

    Full Text Available Side-type orifice intake is a type of selective withdrawal facility used in managing reservoirs to mitigate the negative effects of low-temperature water. Based on the temperature data of a thermal stratified reservoir in China, an experiment was conducted in flume to study the influence of intake flow rate on withdrawn water temperature with different temperature distributions. Results indicated that withdrawn water temperature changed with different flow rates. The temperature change was determined by the water temperature gradients above and below the intake, whereas the change trend of temperature depended on the difference between the water temperature gradient above and below the intake. We likewise proposed a new equation with which the withdrawn water temperature of a thermal stratified reservoir using a side-type orifice could be calculated. These findings could be directly applied to the design and operation of side-type orifice intake in thermal stratified reservoirs.

  12. Effect of flow rate of side-type orifice intake on withdrawn water temperature.

    Science.gov (United States)

    Gao, Xueping; Li, Guangning; Han, Yunpeng

    2014-01-01

    Side-type orifice intake is a type of selective withdrawal facility used in managing reservoirs to mitigate the negative effects of low-temperature water. Based on the temperature data of a thermal stratified reservoir in China, an experiment was conducted in flume to study the influence of intake flow rate on withdrawn water temperature with different temperature distributions. Results indicated that withdrawn water temperature changed with different flow rates. The temperature change was determined by the water temperature gradients above and below the intake, whereas the change trend of temperature depended on the difference between the water temperature gradient above and below the intake. We likewise proposed a new equation with which the withdrawn water temperature of a thermal stratified reservoir using a side-type orifice could be calculated. These findings could be directly applied to the design and operation of side-type orifice intake in thermal stratified reservoirs.

  13. Isotopic evidence of complex ground-water flow at Yucca mountain, Nevada, USA

    Science.gov (United States)

    Peterman, Zell E.; Stuckless, John S.

    1993-01-01

    Strontium isotopes (expressed as per mill deviation from mean sea water, ??87Sr) reflect interaction between ground water and the aquifer through which it is flowing. In the Cenozoic aquifer of the Yucca Mountain region, ??87Sr values increase from north to south downgradient in the flow system. The largest ??87Sr values occur in the Amargosa Desert where ground water probably encounters alluvial basin fill derived from Precambrian rocks in the Funeral Range. Similarly, large ??87Sr values for ground water in the Paleozoic aquifer at the western end of the Spring Mountains also probably reflect an encounter with Precambrian rocks. In several wells into the volcanic rocks, apparent isotopic disequilibrium between ground water and the producing units suggests that the ground water probably integrates over a substantial part of the saturated section in attaining its strontium isotope signature.

  14. Ultrabroadband THz Time-Domain Spectroscopy of a Free-Flowing Water Film

    DEFF Research Database (Denmark)

    Wang, Tianwu; Pedersen, Pernille Klarskov; Jepsen, Peter Uhd

    2014-01-01

    We demonstrate quantitative ultrabroadband THz time-domain spectroscopy (THz-TDS) of water by application of a 17-$\\mu$m thick gravity-driven wire-guided flow jet of water. The thickness and stability of the water film is accurately measured by an optical intensity crosscorrelator, and the standard...... deviation of the film thickness is less than 500 nm. The cross section of the water film is found to have a biconcave cylindrical lens shape. By transmitting through such a thin film, we perform the first ultrabroadband (0.2–30 THz) THz-TDS across the strongest absorbing part of the infrared spectrum...... of liquid water using two different THz-TDS setups. The extracted absorption coefficient and refractive index of water are in agreement with previous results reported in the literature. With this we show that the thin free-flowing liquid film is a versatile tool for windowless, ultrabroadband THz...

  15. Redistribution of filtration flows by thermogel at boundary water flooding of oil reservoirs

    Science.gov (United States)

    Korsakova, N. K.; Penkovsky, V. I.; Altunina, L. K.; Kuvshinov, V. A.

    2016-11-01

    The results of physical simulation by a two-dimensional reservoir model and numerical calculation by a finite element method for the GALKA-NT thermogel influence on the redistribution of filtration flows of injected water in the oil production by boundary water flooding are presented. The reserve development by this method, especially in the case of viscose oil pools, occurs with an unstable displacement front that causes growing water fingers, which finally transform into the network of water-conducting channels in the direction of the least filtration resistance between well rows. Here the most amount of oil remains in the nonmobile capillary-locked state, which is in dynamic equilibrium with the flow of displacing water. The injection of thermogel into the reservoir area between the wells is shown to widen the displacement front and to increase the reservoir coverage by water flooding at a later stage in order to enhance oil recovery.

  16. Malignant human cell transformation of Marcellus shale gas drilling flow back water

    Science.gov (United States)

    Yao, Yixin; Chen, Tingting; Shen, Steven S.; Niu, Yingmei; DesMarais, Thomas L; Linn, Reka; Saunders, Eric; Fan, Zhihua; Lioy, Paul; Kluz, Thomas; Chen, Lung-Chi; Wu, Zhuangchun; Costa, Max

    2015-01-01

    The rapid development of high-volume horizontal hydraulic fracturing for mining natural gas from shale has posed potential impacts on human health and biodiversity. The produced flow back waters after hydraulic stimulation is known to carry high levels of saline and total dissolved solids. To understand the toxicity and potential carcinogenic effects of these waste waters, flow back water from five Marcellus hydraulic fracturing oil and gas wells were analyzed. The physicochemical nature of these samples was analyzed by inductively coupled plasma mass spectrometry and scanning electron microscopy / energy dispersive X-ray spectroscopy. A cytotoxicity study using colony formation as the endpoint was carried out to define the LC50 values of test samples using human bronchial epithelial cells (BEAS-2B). The BEAS-2B cell transformation assay was employed to assess the carcinogenic potential of the samples. Barium and strontium were among the most abundant metals in these samples and the same metals were found elevated in BEAS-2B cells after long-term treatment. BEAS-2B cells treated for 6 weeks with flow back waters produced colony formation in soft agar that was concentration dependant. In addition, flow back water-transformed BEAS-2B cells show a better migration capability when compared to control cells. This study provides information needed to assess the potential health impact of post-hydraulic fracturing flow back waters from Marcellus Shale natural gas mining. PMID:26210350

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

    Science.gov (United States)

    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.

  18. Optimality and Conductivity for Water Flow: From Landscapes, to Unsaturated Soils, to Plant Leaves

    Energy Technology Data Exchange (ETDEWEB)

    Liu, H.H.

    2012-02-23

    Optimality principles have been widely used in many areas. Based on an optimality principle that any flow field will tend toward a minimum in the energy dissipation rate, this work shows that there exists a unified form of conductivity relationship for three different flow systems: landscapes, unsaturated soils and plant leaves. The conductivity, the ratio of water flux to energy gradient, is a power function of water flux although the power value is system dependent. This relationship indicates that to minimize energy dissipation rate for a whole system, water flow has a small resistance (or a large conductivity) at a location of large water flux. Empirical evidence supports validity of the relationship for landscape and unsaturated soils (under gravity dominated conditions). Numerical simulation results also show that the relationship can capture the key features of hydraulic structure for a plant leaf, although more studies are needed to further confirm its validity. Especially, it is of interest that according to this relationship, hydraulic conductivity for gravity-dominated unsaturated flow, unlike that defined in the classic theories, depends on not only capillary pressure (or saturation), but also the water flux. Use of the optimality principle allows for determining useful results that are applicable to a broad range of areas involving highly non-linear processes and may not be possible to obtain from classic theories describing water flow processes.

  19. Effect of water flow rate and feed training on "pacamã" (Siluriforme: Pseudopimelodidae juvenile production

    Directory of Open Access Journals (Sweden)

    R.K. Luz

    2011-08-01

    Full Text Available The effects of different water flow rates and feed training on the production of "pacamã" Lophiosilurus alexandri juveniles were evaluated. In the first experiment, nine day post-hatch larvae (n= 2,400 were stocked at a density of 5 larvae/L. Different water flow (F rates were tested: F1 = 180; F2 = 600; F3 = 1,300; and F4 = 2,600mL/min. Artemia nauplii were offered as food during the first 15 days of active feeding. In the second experiment for feed training, 720 juveniles (total length of 22.2mm were stocked at a density of 1.5 juveniles/L. A water flow rate similar to F1 was used. The use of extruded dry diet was tested, and feed training was done with and without other enhanced flavors (Artemia nauplii or Scott emulsion. The water flow rates did not influence the survival or growth of L. alexandri. Cannibalism occurred during feed training. The worst survival, specific growth rate and high mortality were found with the use of extruded dry diet, while similar values were registered with the different feed training diets used. Reduced water flow rate can be used to lower water consumption during larviculture and feed training of L. alexandri.

  20. Demonstration of a plasma mirror based on a laminar flow water film

    Energy Technology Data Exchange (ETDEWEB)

    Panasenko, Dmitriy; Shu, Anthony; Gonsalves, Anthony; Nakamura, Kei; Matlis, Nicholas; Toth, Csaba; Leemans, Wim

    2011-07-22

    A plasma mirror based on a laminar water film with low flow speed 0.5-2 cm/s has been developed and characterized, for use as an ultrahigh intensity optical reflector. The use of flowing water as atarget surface automatically results in each laser pulse seeing a new interaction surface and avoids the need for mechanical scanning of the target surface. In addition, the breakdown of water does notproduce contaminating debris that can be deleterious to vacuum chamber conditions and optics, such as is the case when using conventional solid targets. The mirror exhibits 70percent reflectivity, whilemaintaining high-quality of the reflected spot.

  1. Effects of preferential flow on soil-water and surface runoff in a forested watershed in China

    Institute of Scientific and Technical Information of China (English)

    Jinhua CHENG; Hongjiang ZHANG; Youyan ZHANG; Yuhu SHI; Yun CHENG

    2009-01-01

    Preferential flow is a runoff mechanism intermediate between matrix flow and surface flow, transmitting water at high velocity through the subsurface zone. To assess the effect of preferential flow on soil-water flow and surface runoff in a forested watershed, precipitation and volumes of preferential flow, matrix flow and surface runoff were measured over a period of four years in a forested watershed in the Three Gorges area of southern China. Results show that preferential-flow hydrographs have gentler rises and steeper recessions than those for matrix flow and surface runoff. Preferential flow as a percentage of soil-water flow ranged from 2.40% to 8.72% and the maximum preferential-flow velocity exceeded as much as 5600 times that of matrix flow. This shows that preferential flow plays an important role in the movement of soil water. Preferential flow has a significant effect on peak surface runoff by increasing the surface runoff rate and accelerating the appearance of peak surface runoff. Preferential flow can also prolong the duration of surface runoff. Surface runoff was observed to be positively correlated with preferential flow. The greater the sum of rainfall amount and antecedent precipitation is, the greater the effect of preferential flow on surface runoff is.

  2. Multi-scale field investigation of water flow pathways and residence times in mountainous catchments

    Science.gov (United States)

    Lyon, S. W.; Troch, P. A.; Desilets, S. E.

    2006-12-01

    The "sky islands" of Arizona and New Mexico in the southwestern United States form a unique complex of about 27 mountain ranges whose ecosystems support many perennial and ephemeral streams in an arid climate. Among these sky islands are the Santa Catalina Mountains near Tucson, AZ, with a peak elevation of 9157 ft at Mt. Lemmon. Sabino Canyon Creek is the main stream which runs on the south face of the mountain range. It usually flows from July through April with an average daily flow of approximately 0.28 m3/s (10 cfs). However, flash floods are common both during summer as a result of intense monsoon rains and during spring because of rapid snowmelt. During these events, flow increases rapidally, reaching peak flows up to 480 m3/s (16,000 cfs, July 2006). Characterizing water flow pathways and residence times in these complex catchments is important for improving flash flood warning systems, estimating mountain front recharge, managing forest and wild fires, and understanding ecosystem functions. In the summer of 2006, we set up an extensive hydrometrical and hydro-chemical monitoring network in Sabino Canyon Creek, comprising 40 tipping bucket rain gauges (two of which were equipped to automatically collect rainwater samples), 5 automatic surface water level stations (three of which were equipped with auto samplers), and 8 manual soil lysimeters. In addition, several rain and stream water grab samples were collected manually during intensive rain events. Water samples are analyzed for major ions and liquid water isotopic concentration (2H and 18O) in rain, soil, ground and surface water. The data allows for a detailed reconstruction of water flow pathways and residence times at 3 different catchment scales (2 km2, 8 km2, and 91 km2) during the recorded flow events, including the highest monsoon rainfall-runoff event ever recorded in these mountains.

  3. Attenuation of concentration fluctuations of water vapor and other trace gases in turbulent tube flow

    DEFF Research Database (Denmark)

    Massman, W.J.; Ibrom, Andreas

    2008-01-01

    Recent studies with closed-path eddy covariance (EC) systems have indicated that the attenuation of fluctuations of water vapor concentration is dependent upon ambient relative humidity, presumably due to sorption/desorption of water molecules at the interior surface of the tube. Previous studies...... of EC-related tube attenuation effects have either not considered this issue at all or have only examined it superficially. Nonetheless, the attenuation of water vapor fluctuations is clearly much greater than might be expected from a passive tracer in turbulent tube flow. This study reexamines...... the turbulent tube flow issue for both passive and sorbing tracers with the intent of developing a physically-based semi-empirical model that describes the attenuation associated with water vapor fluctuations. Toward this end, we develop a new model of tube flow dynamics (radial profiles of the turbulent...

  4. The Research on Metrological Characteristics of House Water Meters during Transitional Flow Regimes

    Directory of Open Access Journals (Sweden)

    Inga Briliūtė

    2011-04-01

    Full Text Available The purpose of this research is to find the influence of transitional flow regimes on inlet water meters. Four construction types of mechanical inlet water meters (each capacity Q = 10 m3/h were investigated. The biggest additional volume 0,12–0,26% when Q = 0,2…2 m3/h shows single-jet vane wheel meter. This additional volume is less 0,06–0,13% for the multi-jet concentric water meter. The minimum influence of transitional flow regimes was for turbine water meters till 0,1% for all flow range. The volumetric meters are not sensitive for this effect.Article in Lithuanian

  5. Study and application of a high-pressure water jet multi-functional flow test system

    Science.gov (United States)

    Shi, Huaizhong; Li, Gensheng; Huang, Zhongwei; Li, Jingbin; Zhang, Yi

    2015-12-01

    As the exploration and development of oil and gas focus more and more on deeper formation, hydraulic issues such as high-pressure water jet rock breaking, wellbore multiphase flow law, cuttings carrying efficiency, and hydraulic fracturing technique during the drilling and completion process have become the key points. To accomplish related researches, a high-pressure water jet multi-functional flow test system was designed. The following novel researches are carried out: study of high-pressure water jet characteristics under confining pressure, wellbore multiphase flow regime, hydraulic pressure properties of down hole tools during jet fracturing and pulsed cavitation jet drilling, and deflector's friction in radial jet drilling. The validity and feasibility of the experimental results provided by the system with various test modules have proved its importance in the research of the high-pressure water jet and well completion technology.

  6. Laminar premixed methane/air flame extinction characteristics influenced by co-flow water mists

    Institute of Scientific and Technical Information of China (English)

    LIU XuanYa; LU ShouXiang; ZHU YingChun; LIU Yi

    2008-01-01

    Based on the tubular burner, the burning velocities, flame stretch and inhibition rules influenced by co-flow water mists were studied using a high-speed schlieren system. Moreover, the variation rules of the flame critical extinction in our burner equipment were also obtained by analyzing the process and mechanism of flame extinction and inhibition. It is shown that the flame stretch is related to the fuel concentration, co-flow fluxes and water mist diameters. For droplets with a larger diameter, the smaller the co-flow fluxes, the more obvious the flame stretch. When the water mist loading rate is rather smaller, for fuel-rich premixed flame with Le>1, the flame with larger burning rate tends to backfire more easily. Under the same water mist conditions, for fuel-lean premixed flame with Le<1, the smaller the gas concentration, the easier the flame is extinct.

  7. The mechanism of the flowing ground water impacting on coalbed gas content

    Institute of Scientific and Technical Information of China (English)

    QIN Shengfei; SONG Yan; TANG Xiuyi; FU Guoyou

    2005-01-01

    The hydrogeological condition affects the coalbed gas storage dramatically. In an area of stronger hydrodynamics, the coal has a lower gas content, while a higher gas content exists in an area of weaker hydrodynamics. Obviously, the flowing groundwater is harmful to coalbed gas preservation. But few researches focus on the mechanism of how the flowing water diminishes the coalbed gas content.Based on the phenomenon that the flowing groundwater not only makes coalbed gas content lower, but also fractionates the carbon isotope, this research puts forward an idea that it is the water solution that diminishes the coalbed gas content,rather than the water-driven action or the gas dissipation through cap rocks. Only water-soluble action can both fractionate the carbon isotope and lessen the coalbed gas content,and it is an efficient way to take gas away and affect the gas content.

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

    Science.gov (United States)

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

    2014-10-20

    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.

  9. Measurement of Vapor Flow As an Important Source of Water in Dry Land Eco-Hydrology

    Science.gov (United States)

    Wang, Z.; He, Z.; Wang, Y.; Gao, Z.; Hishida, K.

    2014-12-01

    When the temperature of land surface is lower than that of air and deeper soils, water vapor gathers toward the ground surface where dew maybe formed depending on the prevailing dew point and wind speed. Some plants are able to absorb the dew and vapor flow while the soil can readily absorb both. Certain animals such as desert beetles and ants harvest the dew or fog for daily survival. Recently, it is also realized that the dew and vapor flow can be a life-saving amount of water for plant survival at the driest seasons of the year in arid and semi-arid regions. Researches are conducted to quantify the amount of near-surface vapor flow in arid and semi-arid regions in China and USA. Quantitative leaf water absorption and desorption functions were derived based on laboratory experiments. Results show that plant leaves absorb and release water at different speeds depending on species and varieties. The "ideal" native plants in the dry climates can quickly absorb water and slowly release it. This water-holding capacity of plant is characterized by the absorption and desorption functions derived for plant physiology and water balance studies. Field studies are conducted to measure the dynamic vapor flow movements from the atmosphere and the groundwater table to soil surface. Results show that dew is usually formed on soil and plant surfaces during the daily hours when the temperature gradients are inverted toward the soil surface. The amount of dew harvested using gravels on the soil surface was enough to support water melon agriculture on deserts. The vapor flow can be effectively intercepted by artificially seeded plants in semi-arid regions forming new forests. New studies are attempted to quantify the role of vapor flow for the survival of giant sequoias in the southern Sierra Nevada Mountains of California.

  10. A new formulation to compute self-potential signals associated with ground water flow

    Directory of Open Access Journals (Sweden)

    A. Bolève

    2007-06-01

    Full Text Available The classical formulation of the coupled hydroelectrical flow in porous media is based on a linear formulation of two coupled constitutive equations for the electrical current density and the seepage velocity of the water phase and obeying Onsager's reciprocity. This formulation shows that the streaming current density is controlled by the gradient of the fluid pressure of the water phase and a streaming current coupling coefficient that depends on the so-called zeta potential. Recently a new formulation has been introduced in which the streaming current density is directly connected to the seepage velocity of the water phase and to the excess of electrical charge per unit pore volume in the porous material. The advantages of this formulation are numerous. First this new formulation is more intuitive not only in terms of constitutive equation for the generalized Ohm's law but also in specifying boundary conditions for the influence of the flow field upon the streaming potential. With the new formulation, the streaming potential coupling coefficient shows a decrease of its magnitude with permeability in agreement with published results. The new formulation is also easily extendable to non-viscous laminar flow problems (high Reynolds number ground water flow in cracks for example and to unsaturated conditions with applications to the vadose zone. We demonstrate here that this formulation is suitable to model self-potential signals in the field. We investigate infiltration of water from an agricultural ditch, vertical infiltration of water into a sinkhole, and preferential horizontal flow of ground water in a paleochannel. For the three cases reported in the present study, a good match is obtained between the finite element simulations performed with the finite element code Comsol Multiphysics 3.3 and field observations. Finally, this formulation seems also very promising for the inversion of the geometry of ground water flow from the

  11. Instream flow and water availability in the Rio das Pedras basin, Guarapuava-PR, Brazil

    Directory of Open Access Journals (Sweden)

    Ederson Dias de Oliveira

    2012-12-01

    Full Text Available Knowledge of instream flow is of paramount importance to determine water availability for water resources management. This study estimated instream flow and evaluated water availability in the stretch of the Rio das Pedras, which supplies water to Guarapuava, a town in the mid-southern region of the state of Paraná, Brazil. Several different methods were employed to obtain instream flow, a reference discharge for water consumption permit, and the river regime. Methods comprised 7-day mean minimum with a 10-year return period, discharges associated to 95% and 90% permanence, yearly 7-day mean minimum discharge and basic water discharge. Discharge data were obtained from the meteorological station at the Water Station of Guarapuava (ETA. Results show that yearly river debit between 1985 and 2009 had a daily mean of 9.12 m³ s-1 and a median discharge of 9.16 m³ s-1. Estimated instream flow, measured by methods used for the Rio das Pedras stretch, ranged from 1.72 to 2.74 m³ s-1, with an average of 2.20 m³ s-1 and a coefficient of variation of 19.5%. Discharge for the stretch was estimated as 0.91 m³ s-1, following criteria used in the state of Paraná. The relationship of the evaluated stretch between daily flow and the intake volume granted by the government revealed the inefficiency of the applied methods for instream flow assessment. In fact, they failed to warrant a minimum water volume required for the conservation of the river ecosystem.

  12. The Finite Element Analysis for a Mini-Conductance Probe in Horizontal Oil-Water Two-Phase Flow

    Directory of Open Access Journals (Sweden)

    Weihang Kong

    2016-08-01

    Full Text Available Oil-water two-phase flow is widespread in petroleum industry processes. The study of oil-water two-phase flow in horizontal pipes and the liquid holdup measurement of oil-water two-phase flow are of great importance for the optimization of the oil production process. This paper presents a novel sensor, i.e., a mini-conductance probe (MCP for measuring pure-water phase conductivity of oil-water segregated flow in horizontal pipes. The MCP solves the difficult problem of obtaining the pure-water correction for water holdup measurements by using a ring-shaped conductivity water-cut meter (RSCWCM. Firstly, using the finite element method (FEM, the spatial sensitivity field of the MCP is investigated and the optimized MCP geometry structure is determined in terms of the characteristic parameters. Then, the responses of the MCP for the oil-water segregated flow are calculated, and it is found that the MCP has better stability and sensitivity to the variation of water-layer thickness in the condition of high water holdup and low flow velocity. Finally, the static experiments for the oil-water segregated flow were carried out and a novel calibration method for pure-water phase conductivity measurements was presented. The validity of the pure-water phase conductivity measurement with segregated flow in horizontal pipes was verified by experimental results.

  13. The Finite Element Analysis for a Mini-Conductance Probe in Horizontal Oil-Water Two-Phase Flow.

    Science.gov (United States)

    Kong, Weihang; Kong, Lingfu; Li, Lei; Liu, Xingbin; Xie, Ronghua; Li, Jun; Tang, Haitao

    2016-08-24

    Oil-water two-phase flow is widespread in petroleum industry processes. The study of oil-water two-phase flow in horizontal pipes and the liquid holdup measurement of oil-water two-phase flow are of great importance for the optimization of the oil production process. This paper presents a novel sensor, i.e., a mini-conductance probe (MCP) for measuring pure-water phase conductivity of oil-water segregated flow in horizontal pipes. The MCP solves the difficult problem of obtaining the pure-water correction for water holdup measurements by using a ring-shaped conductivity water-cut meter (RSCWCM). Firstly, using the finite element method (FEM), the spatial sensitivity field of the MCP is investigated and the optimized MCP geometry structure is determined in terms of the characteristic parameters. Then, the responses of the MCP for the oil-water segregated flow are calculated, and it is found that the MCP has better stability and sensitivity to the variation of water-layer thickness in the condition of high water holdup and low flow velocity. Finally, the static experiments for the oil-water segregated flow were carried out and a novel calibration method for pure-water phase conductivity measurements was presented. The validity of the pure-water phase conductivity measurement with segregated flow in horizontal pipes was verified by experimental results.

  14. An assessment of aquifer storage recovery using ground water flow models.

    Science.gov (United States)

    Lowry, Christopher S; Anderson, Mary P

    2006-01-01

    Owing to increased demands on ground water accompanied by increased drawdowns, technologies that use recharge options, such as aquifer storage recovery (ASR), are being used to optimize available water resources and reduce adverse effects of pumping. In this paper, three representative ground water flow models were created to assess the impact of hydrogeologic and operational parameters/factors on recovery efficiency of ASR systems. Flow/particle tracking and solute transport models were used to track the movement of water during injection, storage, and recovery. Results from particle tracking models consistently produced higher recovery efficiency than the solute transport models for the parameters/properties examined because the particle tracking models neglected mixing of the injected and ambient water. Mixing between injected and ambient water affected recovery efficiency. Results from this study demonstrate the interactions between hydrogeologic and operational parameters on predictions of recovery efficiency. These interactions are best simulated using coupled numerical ground water flow and transport models that include the effects of mixing of injected water and ambient ground water.

  15. Coupled Dynamics of Turbulent Water Flow and Non-Spherical Particles Through Novel Measurement Method

    Science.gov (United States)

    Byron, M.; Meyer, C.; Bellani, G.; Variano, E. A.

    2011-12-01

    We present a method for simultaneously measuring both the fluid and particle phases in a dense particle-laden flow or slurry. There is no limit to the technique's ability to resolve very high particle number density. With this, we measure the motion of particles in high-Reynolds number turbulent water flow. The particles we consider include spheres, ellipsoids, and completely irregular geometries. The particles range from near neutrally buoyant to a specific gravity of 2. We measure the particles' translation and rotation, while simultaneously measuring the turbulent flow surrounding them. With this information, we can determine: the effect of particles on turbulent flow (e.g. enhanced dissipation); the effect of turbulent flow on particle (e.g. eddy diffusivity and modified settling velocity); and the dynamics at the particle interfaces which explain theses effects. In this presentation, we explain the method; present results on the rotational diffusion of particles; and present results on how particles affect the ambient turbulent flow.

  16. Ion distribution measured by electron probe X-ray microanalysis in apoplastic and symplastic pathways in root cells in sunflower plants grown in saline medium.

    Science.gov (United States)

    Ebrahimi, Reza; Bhatla, S C

    2012-09-01

    Little is known about how salinity affects ions distribution in root apoplast and symplast. Using x-ray microanalysis, ions distribution and the relative contribution of apoplastic and symplastic pathways for delivery of ions to root xylem were studied in sunflower plants exposed to moderate salinity (EC=6). Cortical cells provided a considerably extended Na(+) and Cl(-) storage facility. Their contents are greater in cytoplasm (root symplast) as compared to those in intercellular spaces (root apoplast). Hence, in this level of salinity, salt damage in sunflower is not dehydration due to extracellular accumulation of sodium and chloride ions, as suggested in the Oertli hypothesis. On the other hand, reduction in calcium content due to salinity in intercellular space is less than reduction in the cytoplasm of cortical cells. It seems that sodium inhibits the radial movement of calcium in symplastic pathway more than in the apoplastic pathway. The cell wall seems to have an important role in providing calcium for the apoplastic pathway. Redistribution of calcium from the cell wall to intercellular space is because of its tendency towards xylem through the apoplastic pathway. This might be a strategy to enhance loading of calcium to xylem elements and to reduce calcium deficiency in young leaves under salinity. This phenomenon may be able to increase salt tolerance in sunflower plants. Supplemental calcium has been found to be effective in reducing radial transport of Na(+) across the root cells and their loading into the xylem, but not sodium absorption. Supplemental calcium enhanced Ca(2+) uptake and influx into roots and transport to stele.

  17. Ion distribution measured by electron probe X-ray microanalysis in apoplastic and symplastic pathways in root cells in sunflower plants grown in saline medium

    Indian Academy of Sciences (India)

    Reza Ebrahimi; S C Bhatla

    2012-09-01

    Little is known about how salinity affects ions distribution in root apoplast and symplast. Using x-ray microanalysis, ions distribution and the relative contribution of apoplastic and symplastic pathways for delivery of ions to root xylem were studied in sunflower plants exposed to moderate salinity (EC=6). Cortical cells provided a considerably extended Na+ and Cl− storage facility. Their contents are greater in cytoplasm (root symplast) as compared to those in intercellular spaces (root apoplast). Hence, in this level of salinity, salt damage in sunflower is not dehydration due to extracellular accumulation of sodium and chloride ions, as suggested in the Oertli hypothesis. On the other hand, reduction in calcium content due to salinity in intercellular space is less than reduction in the cytoplasm of cortical cells. It seems that sodium inhibits the radial movement of calcium in symplastic pathway more than in the apoplastic pathway. The cell wall seems to have an important role in providing calcium for the apoplastic pathway. Redistribution of calcium from the cell wall to intercellular space is because of its tendency towards xylem through the apoplastic pathway. This might be a strategy to enhance loading of calcium to xylem elements and to reduce calcium deficiency in young leaves under salinity. This phenomenon may be able to increase salt tolerance in sunflower plants. Supplemental calcium has been found to be effective in reducing radial transport of Na+ across the root cells and their loading into the xylem, but not sodium absorption. Supplemental calcium enhanced Ca2+ uptake and influx into roots and transport to stele.

  18. UNDERWATER ACOUSTICS AND CAVITATING FLOW OF WATER ENTRY

    Institute of Scientific and Technical Information of China (English)

    SHI Honghui; KUME Makoto

    2004-01-01

    The fluid mechanics of water entry is studied through investigating the underwater acoustics and the supercavitation. Underwater acoustic signals in water entry are extensively measured at about 30 different positions by using a PVDF needle hydrophone. From the measurements we obtain (1) the primary shock wave caused by the impact of the blunt body on free surface; (2) the vapor pressure inside the cavity; (3) the secondary shock wave caused by pulling away of the cavity from free surface; and so on. The supercavitation induced by the blunt body is observed by using a digital high-speed video camera as well as the single shot photography. The periodic and 3 dimensional motion of the supercavitation is revealed. The experiment is carried out at room temperature.

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

    Directory of Open Access Journals (Sweden)

    C. Mathison

    2015-06-01

    Full Text Available 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

  20. Data flows and water woes: The Utah Data Center

    Directory of Open Access Journals (Sweden)

    Mél Hogan

    2015-07-01

    Full Text Available Using a new materialist line of questioning that looks at the agential potentialities of water and its entanglements with Big Data and surveillance, this article explores how the recent Snowden revelations about the National Security Agency (NSA have reignited media scholars to engage with the infrastructures that enable intercepting, hosting, and processing immeasurable amounts of data. Focusing on the expansive architecture, location, and resource dependence of the NSA’s Utah Data Center, I demonstrate how surveillance and privacy can never be disconnected from the material infrastructures that allow and render natural the epistemological state of mass surveillance. Specifically, I explore the NSA’s infrastructure and the million of gallons of water it requires daily to cool its servers, while located in one of the driest states in the US. Complicating surveillance beyond the NSA, as also already imbricated with various social media companies, this article questions the emplacement and impact of corporate data centers more generally, and the changes they are causing to the landscape and local economies. I look at how water is an intriguing and politically relevant part of the surveillance infrastructure and how it has been constructed as the main tool for activism in this case, and how it may eventually help transform the public’s conceptualization of Big Data, as deeply material.

  1. Flow resistance reduction of coal water slurry through gas phase addition

    Directory of Open Access Journals (Sweden)

    Robak Jolanta

    2016-01-01

    Full Text Available One of the main advantages of coal water slurry fuel (CWS is a physical form that allows, among others, their transfer by pipelines over long distances. For this form of transport actions towards reducing the flow resistance of the transmitted medium are important. One of the treatments leading to reduction in the flow resistance of suspensions is to introduce gas into the stream of flowing slurry. The goal of that action is to either loosen the structure of densely packed grains or increase the velocity of the suspension. The paper presents the flow resistance of CWS in a horizontal pipeline and the effect of addition of the gas phase on the resistance level. The investigation was carried out with the use of a research stand enabling to measure the flow resistance of the multiphase/multicomponent systems. The measured diameter and length of sections were respectively: 0.03 and 2 m. The coal-water slurries (based on steam coals with concentration of dry coal in the range of 51 do 60% obtained by wet milling in a drum mill were used. During the tests, the following parameters were measured: slurry flow rate, air flow rate, temperature and pressure difference in inlet and outlet of the measured section. The volume flow rate of slurry fuel was in the range of 30 to 110 dm3/min while the volume flow rate of air was from 0.15 to 4 m3/h. Based on the obtained results, the slurry flow resistance as a function of the flow rate and share of introduced air was evaluated. The performed research allowed for assessment of flow resistance reduction condition and to determine the pipe flow curves for different temperatures. It was found that the effect of reducing the flow resistance of the coal slurry by introducing gas into the flow tube depended on the volumetric flow rate, and thus the linear velocity of the slurry. Under the experimental condition, this effect only occurred at low flow rates (30 - 50 dm3/min and low temperature of the suspension. The

  2. Geohydrological characterization, water-chemistry, and ground-water flow simulation model of the Sonoma Valley area, Sonoma County, California

    Science.gov (United States)

    Farrar, Christopher D.; Metzger, Loren F.; Nishikawa, Tracy; Koczot, Kathryn M.; Reichard, Eric G.; Langenheim, V.E.

    2006-01-01

    The Sonoma Valley, located about 30 miles north of San Francisco, is one of several basins in Sonoma County that use a combination of ground water and water delivered from the Russian River for supply. Over the past 30 years, Sonoma Valley has experienced rapid population growth and land-use changes. In particular, there has been a significant increase in irrigated agriculture, predominantly vineyards. To provide a better understanding of the ground-water/surface-water system in Sonoma Valley, the U.S. Geological Survey compiled and evaluated existing data, collected and analyzed new data, and developed a ground-water flow model to better understand and manage the ground-water system. The new data collected include subsurface lithology, gravity measurements, groundwater levels, streamflow gains and losses, temperature, water chemistry, and stable isotopes. Sonoma Valley is drained by Sonoma Creek, which discharges into San Pablo Bay. The long-term average annual volume of precipitation in the watershed is estimated to be 269,000 acre-feet. Recharge to the ground-water system is primarily from direct precipitation and Sonoma Creek. Discharge from the ground-water system is predominantly outflow to Sonoma Creek, pumpage, and outflow to marshlands and to San Pablo Bay. Geologic units of most importance for groundwater supply are the Quaternary alluvial deposits, the Glen Ellen Formation, the Huichica Formation, and the Sonoma Volcanics. In this report, the ground-water system is divided into three depth-based geohydrologic units: upper (less than 200 feet below land surface), middle (between 200 and 500 feet), and lower (greater than 500 feet). Synoptic streamflow measurements were made along Sonoma Creek and indicate those reaches with statistically significant gains or losses. Changes in ground-water levels in wells were analyzed by comparing historical contour maps with the contour map for 2003. In addition, individual hydrographs were evaluated to assess temporal

  3. Separation of bacterial spores from flowing water in macro-scale cavities by ultrasonic standing waves

    CERN Document Server

    Lipkens, B; Costolo, M; Stevens, A; Rietman, Edward

    2010-01-01

    The separation of micron-sized bacterial spores (Bacillus cereus) from a steady flow of water through the use of ultrasonic standing waves is demonstrated. An ultrasonic resonator with cross-section of 0.0254 m x 0.0254 m has been designed with a flow inlet and outlet for a water stream that ensures laminar flow conditions into and out of the resonator section of the flow tube. A 0.01905-m diameter PZT-4, nominal 2-MHz transducer is used to generate ultrasonic standing waves in the resonator. The acoustic resonator is 0.0356 m from transducer face to the opposite reflector wall with the acoustic field in a direction orthogonal to the water flow direction. At fixed frequency excitation, spores are concentrated at the stable locations of the acoustic radiation force and trapped in the resonator region. The effect of the transducer voltage and frequency on the efficiency of spore capture in the resonator has been investigated. Successful separation of B. cereus spores from water with typical volume flow rates of...

  4. Flow Data for Solute Transport Modeling from Tracer Experiments in a Stream Not Continuously Gaining Water

    Science.gov (United States)

    Bencala, K. E.; Kimball, B. A.; Gooseff, M. N.

    2007-12-01

    In-stream tracer experiments are a well-established method for determining flow data to be incorporated in solute transport modeling. For a gaining stream, this method is implemented to provide spatial flow data at scales of minutes and tens of meters without physical disturbance to the flow of water, the streambed, or biota. Of importance for solute transport modeling, solute inflow loading along the stream can be estimated with this spatial data. The tracer information can also be interpreted to characterize hyporheic exchange time-scales for a stream with hyporheic exchange flowpaths (HEFs) that are short relative to the distance over which the stream gains water. The interpretation of tracer data becomes uncertain for a stream that is not gaining water continuously over intended study reach. We demonstrate, with straight-forward mass-balances, uncertainties for solute loading which arise in the analysis of streams locally losing water while predominantly gaining water (and solutes) over a larger scale. With field data from Mineral Creek (Silverton, Colorado) we illustrate the further uncertainty distinguishing HEFs from (locally) losing segments of the stream. Comparison of bromide tracer with ambient sulfate concentrations suggests that subsurface inflows and outflows, concurrent with likely HEFs, occur in a hydrogeochemical setting of multiple, dispersed and mixed, sources of water along a 64 m sub-reach of the predominately gaining, but locally losing, stream. To compute stream-reach mass-balances (the simplest of water quality models) there is a need to quantitatively define the character and source of contaminants entering streams from ground-water pathways, as well as the potential for changes in water chemistry and contaminant concentrations along flow paths crossing the sediment-water interface. Identification of inflow solute mass requires quantifying water gain, loss, and hyporheic exchange in addition to concentration.

  5. Detection of artificial water flows by the lateral line system of a benthic feeding cichlid fish.

    Science.gov (United States)

    Schwalbe, Margot A B; Sevey, Benjamin J; Webb, Jacqueline F

    2016-04-01

    The mechanosensory lateral line system of fishes detects water motions within a few body lengths of the source. Several types of artificial stimuli have been used to probe lateral line function in the laboratory, but few studies have investigated the role of flow sensing in benthic feeding teleosts. In this study, we used artificial flows emerging from a sandy substrate to assess the contribution of flow sensing to prey detection in the peacock cichlid, Aulonocara stuartgranti, which feeds on benthic invertebrates in Lake Malawi. Using a positive reinforcement protocol, we trained fish to respond to flows lacking the visual and chemical cues generated by tethered prey in prior studies with A. stuartgranti Fish successfully responded to artificial flows at all five rates presented (characterized using digital particle image velocimetry), and showed a range of flow-sensing behaviors, including an unconditioned bite response. Immediately after lateral line inactivation, fish rarely responded to flows and the loss of vital fluorescent staining of hair cells (with 4-di-2-ASP) verified lateral line inactivation. Within 2 days post-treatment, some aspects of flow-sensing behavior returned and after 7 days, flow-sensing behavior and hair cell fluorescence both returned to pre-treatment levels, which is consistent with the reported timing of hair cell regeneration in other vertebrates. The presentation of ecologically relevant water flows to assess flow-sensing behaviors and the use of a positive reinforcement protocol are methods that present new opportunities to study the role of flow sensing in the feeding ecology of benthic feeding fishes.

  6. Estimation of natural historical flows for the Manitowish River near Manitowish Waters, Wisconsin

    Science.gov (United States)

    Juckem, Paul F.; Reneau, Paul C.; Robertson, Dale M.

    2012-01-01

    The Wisconsin Department of Natural Resources is charged with oversight of dam operations throughout Wisconsin and is considering modifications to the operating orders for the Rest Lake Dam in Vilas County, Wisconsin. State law requires that the operation orders be tied to natural low flows at the dam. Because the presence of the dam confounds measurement of natural flows, the U.S. Geological Survey, in cooperation with the Wisconsin Department of Natural Resources, installed streamflow-gaging stations and developed two statistical methods to improve estimates of natural flows at the Rest Lake Dam. Two independent methods were used to estimate daily natural flow for the Manitowish River approximately 1 mile downstream of the Rest Lake Dam. The first method was an adjusted drainage-area ratio method, which used a regression analysis that related measured water yield (flow divided by watershed area) from short-term (2009–11) gaging stations upstream of the Manitowish Chain of Lakes to the water yield from two nearby long-term gaging stations in order to extend the flow record (1991–2011). In this approach, the computed flows into the Chain of Lakes at the upstream gaging stations were multiplied by a coefficient to account for the monthly hydrologic contributions (precipitation, evaporation, groundwater, and runoff) associated with the additional watershed area between the upstream gaging stations and the dam at the outlet of the Chain of Lakes (Rest Lake Dam). The second method used to estimate daily natural flow at the Rest Lake Dam was a water-budget approach, which used lake stage and dam outflow data provided by the dam operator. A water-budget model was constructed and then calibrated with an automated parameter-estimation program by matching simulated flow-duration statistics with measured flow-duration statistics at the upstream gaging stations. After calibration of the water-budget model, the model was used to compute natural flow at the dam from 1973 to

  7. Experimental Investigation on Flow-Induced Vibration of Fuel Rods in Supercritical Water Loop

    Directory of Open Access Journals (Sweden)

    Licun Wu

    2014-01-01

    Full Text Available The supercritical water-cooled reactor (SCWR is one of the most promising Generation IV reactors. In order to make the fuel qualification test for SCWR, a research plan is proposed to test a small scale fuel assembly in a supercritical water loop. To ensure the structure safety of fuel assembly in the loop, a flow-induced vibration experiment was carried out to investigate the vibration behavior of fuel rods, especially the vibration caused by leakage flow. From the experiment result, it can be found that: the vibration of rods is mainly caused by turbulence when flow rate is low. However, the effects of leakage flow become obvious as flow rate increases, which could changes the distribution of vibrational energy in spectrum, increasing the vibrational energy in high-frequency band. That is detrimental to the structure safety of fuel rods. Therefore, it is more reasonable to improve the design by using the spacers with blind hole, which can eliminate the leakage flow, to assemble the fuel rods in supercritical water loop. On the other hand, the experimental result could provide a benchmark for the theoretical studies to validate the applicability of boundary condition set for the leakage-flow-induced vibration.

  8. Neuronal responses to water flow in the marine slug tritonia diomedea

    Directory of Open Access Journals (Sweden)

    Jeffrey Blackwell

    2005-07-01

    Full Text Available The marine slug Tritonia diomedea must rely on its ability to touch and smell in order to navigate because it is blind. The primary factor that influences its crawling direction is the direction of water flow (caused by tides in nature. The sensory cells that detect flow and determine flow direction have not been identified. The lateral branch of Cerebral Nerve 2 (latCeN2 has been identified as the nerve that carries sensory axons to the brain from the flow receptors inthe oral tentacles. Backfilling this nerve to the brain resulted in the labeling of a number of cells located throughout the brain. Most of the labeled cells are concentrated in the cerebral ganglion where the nerve enters the brain. The medial and lateral branches of CeN2 were backfilled for comparison of the pattern of cells from each nerve. A map of the cells innervated by latCeN2 reveals the location of the stained cells. Extracellular recording from latCeN2 revealed its involvement in the detection of water flow and orientation. The nerve becomes active in response to water flow stimulation. Intracellular recordings of the electrical activity of these cells in a live animal will be the next step to determine if these cells are the flow receptors.

  9. Neuronal Responses to Water Flow in the Marine Slug Tritonia diomedea

    Directory of Open Access Journals (Sweden)

    James A. Murray

    2005-01-01

    Full Text Available The marine slug Tritonia diomedea mustrely on its ability to touch and smell in order to navigate because it is blind. The primaryfactor that influences its crawling direction is the direction of water flow (caused bytides in nature. The sensory cells that detect flow and determine flow directionhave not been identified. The lateral branch of Cerebral Nerve 2 (latCeN2 has beenidentified as the nerve that carries sensory axons to the brain from the flow receptors inthe oral tentacles. Backfilling this nerve to the brain resulted in the labeling of a numberof cells located throughout the brain. Most of the labeled cells are concentrated in the cerebral ganglion where the nerve enters thebrain. The medial and lateral branches of CeN2 were backfilled for comparison of thepattern of cells from each nerve. A map of the cells innervated by latCeN2 reveals thelocation of the stained cells. Extracellular recording from latCeN2 revealed itsinvolvement in the detection of water flow and orientation. The nerve becomes activein response to water flow stimulation. Intracellular recordings of the electricalactivity of these cells in a live animal will be the next step to determine if these cells arethe flow receptors.

  10. Investigation of particle detachment and transport in raindrop impacted thin water flows under highly controlled conditions

    Science.gov (United States)

    Fister, Wolfgang; Kinnell, Peter I.; Greenwood, Philip; Kuhn, Nikolaus J.

    2016-04-01

    Small scale processes, such as splash, sheet, and interrill erosion mechanisms, can be studied with a very high degree of precision and accuracy. However, a major problem when performing investigations on raindrop impacted thin water flows is that accurate measurements of key erosion variables are difficult to obtain. In many investigations, important values are, therefore, not directly measured, but inferred from easier to determine parameters. For example rainfall intensity, plot dimension, and flow discharge are recorded during an experiment to rather crudely estimate velocity and depth of flow. Since water depth and flow velocity vary spatially and temporally during experiments with non-controlled flow conditions, this lack of measurement accuracy clearly reduces the explanatory power of the experimental data and could be a reason why it is still not possible to deduce exact physical formulas to precisely model soil erosion mechanisms. In order to be able to control and manipulate the key factors governing erosion processes in raindrop impacted thin surface flows, a special experimental setup and measurement protocol was designed. During the experiments, factors like rainfall (drop size, fall velocity, kinetic energy), flow velocity, and particle size were kept constant to reduce the complexity of the system and provide a better opportunity to precisely evaluate the effect of water depth, water discharge, and slope angle on erosion amounts. The used water depths ranged between 2.5 - 10 mm, water discharge between 100-700 l/h, and slope angle between 0-2°. The results of these preliminary tests show that this experimental setup and protocol is capable of producing reproducible, high quality datasets. In future, this device will be used to for example investigate varying sand-size mixtures, varying kinds of substrates, such as a biochar/sand/soil mixture, until natural soil monoliths will be analysed.

  11. Apoplastic peroxidases are required for salicylic acid-mediated defense against Pseudomonas syringae.

    Science.gov (United States)

    Mammarella, Nicole D; Cheng, Zhenyu; Fu, Zheng Qing; Daudi, Arsalan; Bolwell, G Paul; Dong, Xinnian; Ausubel, Frederick M

    2015-04-01

    Reactive oxygen species (ROS) generated by NADPH oxidases or apoplastic peroxidases play an important role in the plant defense response. Diminished expression of at least two Arabidopsis thaliana peroxidase encoding genes, PRX33 (At3g49110) and PRX34 (At3g49120), as a consequence of anti-sense expression of a heterologous French bean peroxidase gene (asFBP1.1), were previously shown to result in reduced levels of ROS following pathogen attack, enhanced susceptibility to a variety of bacterial and fungal pathogens, and reduced levels of callose production and defense-related gene expression in response to the microbe associated molecular pattern (MAMP) molecules flg22 and elf26. These data demonstrated that the peroxidase-dependent oxidative burst plays an important role in the elicitation of pattern-triggered immunity (PTI). Further work reported in this paper, however, shows that asFBP1.1 antisense plants are not impaired in all PTI-associated responses. For example, some but not all flg22-elicited genes are induced to lower levels by flg22 in asFPB1.1, and callose deposition in asFPB1.1 is similar to wild-type following infiltration with a Pseudomonas syringae hrcC mutant or with non-host P. syringae pathovars. Moreover, asFPB1.1 plants did not exhibit any apparent defect in their ability to mount a hypersensitive response (HR). On the other hand, salicylic acid (SA)-mediated activation of PR1 was dramatically impaired in asFPB1.1 plants. In addition, P. syringae-elicited expression of many genes known to be SA-dependent was significantly reduced in asFBP1.1 plants. Consistent with this latter result, in asFBP1.1 plants the key regulator of SA-mediated responses, NPR1, showed both dramatically decreased total protein abundance and a failure to monomerize, which is required for its translocation into the nucleus.

  12. Flow study on the ESS target water model using the UVP method

    Energy Technology Data Exchange (ETDEWEB)

    Haga, Katsuhiro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Takeda, Yasushi; Bauer, G.; Guttek, B.

    1999-03-01

    The European Spallation Source (ESS) is a next generation neutron source using a proton accelerator which generates a high power proton beam of 5 MW. In the conceptual design of the ESS target, the heavy liquid metal, mercury, is used as the target material to endure the high heat load caused by the spallation reaction. The mercury target container is partitioned into three inlet and one outlet channels. One of the key issues to keep its structural integrity is to suppress recirculation flows in the outlet channel so as not be lead excessive temperature rises of the mercury which will cause boiling. To investigate flow behaviors in the ESS target container, a mock-up model was fabricated with plexiglass at the Forschungszentrum Juelich (KFA) in Germany. The experiments were carried out under water flow conditions. Flow velocity fields were measured with the Ultrasound Doppler Velocity Profile Method developed at the Paul Scherrer Institute (PSI) in Switzerland. In the experiments, flow rate ratios of the inlet channels (A, B, C) were changed under a constant total flow rate of 0.88L/s as 1:0:1, 2:1:2, 1:1:1, 1:2:1 and 0:1:0. The recirculation flow was observed from the velocity patterns measured under each flow rate ratio. Flow patterns in the cross section of the recirculation flow showed large vortex structures, and the length of the recirculation flow region increased with the flow rate of the bottom inlet channel. On the bases of these experimental results, it can be said that the creation of the recirculation flow might be inevitable in this target structure of the return-flow type. (author)

  13. Assessment of overland flow variation and blue water production in a farmed semi-arid water harvesting catchment

    Science.gov (United States)

    Mekki, I.; Albergel, J.; Ben Mechlia, N.; Voltz, M.

    Upgrading agriculture in semi-arid areas and ensuring its sustainability require an optimal management of rainfall partition between blue and green waters in the farmed water harvesting catchment. The main objective of this study is to analyze the influence of heterogeneous land use on the spatial and temporal variation of rainfall partitioning and blue water production within a typical farmed catchment located in north-eastern Tunisia. The catchment has an area of 2.6 km 2 and comprises at its outlet a dam, which retains the runoff water in a reservoir. Overland flow and soil water balance components were monitored during two cropping seasons (2000/2001 and 2001/2002) on a network of eleven plots of 2 m 2 each with different land use and soil characteristics. The hydrological balances of both the catchment and reservoir have been monitored since 1994. Observed data showed a very large temporal and spatial variability of overland flow within the catchment reflecting the great importance of total rainfall as well as land use. During the 2001/2002 season the results showed a large variation of the number of observed runoff events, from 27 to 39, and of the annual overland flow depths, from 8 mm (under vineyard on calcaric cambisols) up to 43 mm (under shrubs-pasture on haplic regosols), between the plots. The annual runoff amounts were moderate; they always corresponded to less than 15% of the annual rainfall amount whatever the observation scale. It was also observed that changes in land use in years with similar rainfall could lead to significant differences in blue water flow. An attempt for predicting the overland flow by the general linear regression approach showed an r2 of 31%, the predictors used are the class of soil infiltration capacity, the initial moisture saturation ratio of the soil surface layer and the total rainfall amounts. These experimental results indicate that the variation in land use in a semi-arid catchment is a main factor of variation in

  14. Testing for Nonlinearity in Dynamic Characteristics of Vertical Upward Oil-Gas-Water Three-phase Bubble and Slug Flows

    Institute of Scientific and Technical Information of China (English)

    朱雷; 金宁德; 高忠科; 杜萌; 王振亚

    2012-01-01

    Based on the conductance fluctuation signals measured from vertical upward oil-gas-water three-phase flow experiment, time frequency representation and surrogate data method were used to investigate dynamical characteristics of oil-in-water type bubble and slug flows. The results indicate that oil-in-water type bubble flow will turn to deterministic motion with the increase of oil phase fraction f o and superficial gas velocity U sg under fixed flowrate of oil-water mixture Q mix . The dynamics of oil-in-water type slug flow becomes more complex with the increase of U sg under fixed flowrate of oil-water mixture. The change of f o leads to irregular influence on the dynamics of slug flow. These interesting findings suggest that the surrogate data method can be a faithful tool for characterizing dynamic characteristics of oil-in-water type bubble and slug flows.

  15. Hydraulic Bureaucracies and the Hydraulic Mission: Flows of Water, Flows of Power

    Directory of Open Access Journals (Sweden)

    François Molle

    2009-10-01

    Full Text Available Anchored in 19th century scientism and an ideology of the domination of nature, inspired by colonial hydraulic feats, and fuelled by technological improvements in high dam constructions and power generation and transmission, large-scale water resources development has been a defining feature of the 20th century. Whether out of a need to increase food production, raise rural incomes, or strengthen state building and the legitimacy of the state, governments – North and South, East and West – embraced the 'hydraulic mission' and entrusted it to powerful state water bureaucracies (hydrocracies. Engaged in the pursuit of iconic and symbolic projects, the massive damming of river systems, and the expansion of large-scale public irrigation these hydrocracies have long remained out of reach. While they have enormously contributed to actual welfare, including energy and food generation, flood protection and water supply to urban areas, infrastructural development has often become an end in itself, rather than a means to an end, fuelling rent-seeking and symbolising state power. In many places projects have been challenged on the basis of their economic, social or environmental impacts. Water bureaucracies have been challenged internally (within the state bureaucracies or through political changes and externally (by critiques from civil society and academia, or by reduced funding. They have endeavoured to respond to these challenges by reinventing themselves or deflecting reforms. This paper analyses these transformations, from the emergence of the hydraulic mission and associated water bureaucracies to their adjustment and responses to changing conditions.

  16. Flume experiments on wind induced flow in static water bodies in the presence of protruding vegetation

    Science.gov (United States)

    Banerjee, Tirtha; Muste, Marian; Katul, Gabriel

    2015-02-01

    The problem of wind-induced flow in inland waters is drawing significant research attention given its relevance to a plethora of applications in wetlands including treatment designs, pollution reduction, and biogeochemical cycling. The present work addresses the role of wind induced turbulence and waves within an otherwise static water body in the presence of rigid and flexible emergent vegetation through flume experimentation and time series analysis. Because no prior example of Particle Imaging Velocimetry (PIV) experiments involving air-water and flexible oscillating components have been found in the literature, a spectral analysis framework is needed and proposed here to guide the analysis involving noise, wave and turbulence separation. The experiments reveal that wave and turbulence effects are simultaneously produced at the air-water interface and the nature of their coexistence is found to vary with different flow parameters including water level, mean wind speed, vegetation density and its flexibility. For deep water levels, signature of fine-scaled inertial turbulence is found at deeper layers of the water system. The wave action appears stronger close to the air-water interface and damped by the turbulence deeper inside the water system. As expected, wave action is found to be dominated in a certain frequency range driven by the wind forcing, while it is also diffused to lower frequencies by means of (wind-induced) oscillations in vegetation. Regarding the mean water velocity, existence of a counter-current flow and its switching to fully forward flow in the direction of the wind under certain combinations of flow parameters were studied. The relative importance of wave and turbulence to the overall energy, degree of anisotropy in the turbulent energy components, and turbulent momentum transport at different depths from the air-water interface and flow combinations were then quantified. The flume experiments reported here differ from previous laboratory

  17. Water flowing north of the border: export agriculture and water politics in a rural community in Baja California.

    Science.gov (United States)

    Zlolniski, Christian

    2011-01-01

    Favored by neoliberal agrarian policies, the production of fresh crops for international markets has become a common strategy for economic development in Mexico and other Latin American countries. But as some scholars have argued, the global fresh produce industry in developing countries in which fresh crops are produced for consumer markets in affluent nations implies “virtual water flows,” the transfer of high volumes of water embedded in these crops across international borders. This article examines the local effects of the production of fresh produce in the San Quintín Valley in northwestern Mexico for markets in the United States. Although export agriculture has fostered economic growth and employment opportunities for indigenous farm laborers, it has also led to the overexploitation of underground finite water resources, and an alarming decline of the quantity and quality of water available for residents’ domestic use. I discuss how neoliberal water policies have further contributed to water inequalities along class and ethnic lines, the hardships settlers endure to secure access to water for their basic needs, and the political protests and social tensions water scarcity has triggered in the region. Although the production of fresh crops for international markets is promoted by organizations such as the World Bank and Inter-American Development Bank as a model for economic development, I argue that it often produces water insecurity for the poorest, threatening the UN goal of ensuring access to clean water as a universal human right.

  18. Iron fractions in the apoplast of intact root tips of Zea mays L. seedlings affected by nitrogen form

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The effects of ammonium (NH+4- N ) and ni trate (NO-3- N ) Were examined on Fe fractions and FeCN (ferricyanide) reductase activity in intact root tips (0-3 em)of young maize (Zea mays L. cv. Lenz) in solution culture by using short-term experiment under controlled Fe deficiency conditions (containing high HCO-3 concentration in preculture solution). The results showed that Fe( II ) concentrations in root tip apoplast of maize were only 20-40 nmol/g FW which accounted for 7%-13% of total Fe. Most of Fe in root tips existed as Fe(Ⅲ) compounds. Imposition of the roots to NH+4 - N or NO-3 - N for 60 min led to an increase of Fe( II ) in root tip apoplast. NH+4 - N led to an increased concentration of Fe( II ) and exchangeable Fe (Fe( II ) and Fe (III)) in root tips, while NO-3 - N increased FeCN reductaseactivity. The relationship between pH and Fe fractions,FeCN reductase activity was also discussed.``

  19. On the similarity in shape between debris-flow channels and high-gradient flood channels: Initial insight from continuum models for granular and water flow

    Science.gov (United States)

    Kean, J. W.; McCoy, S. W.; Tucker, G. E.

    2011-12-01

    The cross-sectional shape of high-gradient bedrock channels carved by debris flows is often very similar to that of channels formed by fluvial erosion. Both tend to have narrow U-shapes with width-to-depth ratios much less than 10. Gullies and channels cut into colluvium by both water erosion and debris-flow erosion have similarly narrow geometries. Given that the physics governing debris flow and turbulent water flow are very different, why are channels eroded by these two processes so similar in shape? To begin to investigate this question, we conducted a series of numerical simulations using continuum models for the end-member cases of granular flow and water flow. Each model is used to evolve the steady-state channel shape formed by uniform flow of the respective material. The granular model is based on the constitutive equation for dense granular flow proposed by Jop et al. (Nature, 2006). They demonstrated that without any fitting parameters, a numerical model using this constitutive equation could reproduce the velocity and depth profiles observed in granular-flow laboratory experiments. The model for water flow uses a ray-isovel turbulence closure to calculate the boundary shear stress across the wetted perimeter of the channel. This fully predictive model has also been shown to be in good agreement with laboratory data. We start the calculations for the granular and water-flow cases by determining the velocity and boundary shear-stress fields in an initial V-shape cross section. We then erode both channels using a simple wear law scaled linearly by the bed-normal boundary shear stress. The calculation is repeated until the channel reaches an equilibrium shape. Initial comparisons of the granular and water-flow channels show that they have very similar width-to-depth ratios of about four, and only moderate differences in bottom geometries and boundary shear-stress distributions. The structure of the velocity field differs more substantially between the two

  20. On the turbulent flow around water turbines placed in an open channel: an experimental study

    Science.gov (United States)

    Sotiropoulos, F.; Chamorro, L. P.; Arndt, R.

    2010-12-01

    A growing interest in water turbines (using tidal, river, marine currents) has been observed during the last few years. Fundamental understanding of the turbulent flow around the water turbines is crucial to predict the potential effects of these structures on the local morphology, water flow and power available in the current, among others. In this study, a series of model water turbines (single and an aligned array) of 50 cm rotor diameter were placed in the main channel of the Saint Anthony Falls Laboratory at the University of Minnesota. The main channel is approx 2.5 m wide, 1.8 m height and 85 m long. Flow around the water turbines were analyzed under subcritical conditions. Turbine hub heights coincided with the channel mid height. A series of acoustic Doppler anemometers (ADV) were used to obtain 3 velocity components of the flow at a rate of 200 Hz. Selected streamwise and spanwise vertical planes were measured to describe the kinematics around the water turbines. Potential interactions with the lateral walls were also addressed. High order statistics (mean velocity, turbulence intensities and Reynolds stresses) as well as two point correlations and spectra were computed to infer fundamental differences and similitude with their counterparts, the wind turbines.

  1. SITE-94. Glaciation and regional ground-water flow in the Fennoscandian shield

    Energy Technology Data Exchange (ETDEWEB)

    Provost, A.M.; Voss, C.I.; Neuzil, C.E. [US Geological Survey, Reston, VA (United States)

    1998-02-01

    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. The simulation results suggest that vertical movement of deep shield brines induced by the next few glacial cycles should not increase the concentration of dissolved solids significantly above present-day levels. However, the concentration of dissolved solids should decrease significantly at depths of up to several kilometers during periods of glacial melt water recharge. The melt water may reside in the subsurface for periods exceeding 10 ka and may bring oxygenated conditions to an otherwise reducing chemical environment 33 refs, 32 figs, 4 tabs

  2. Measurement of oil-water flow via the correlation of turbine flow meter, gamma ray densitometry and drift-flux model

    Institute of Scientific and Technical Information of China (English)

    李东晖; 许晶禹

    2015-01-01

    The flow rate of the oil-water horizontal flow is measured by the combination of the turbine flow meter and the single- beam gamma ray densitometry. The emphasis is placed on the effects of the pipe diameter, the oil viscosity and the slip velocity on the measurement accuracy. It is shown that the mixture flow rate measured by the turbine flow meter can meet the application requirement in the water continuous pattern (o-w flow pattern). In addition, by introducing the developed drift-flux model into the measurement system, the relative errors of measurements for component phase flow rates can be controlled within±5%. Although more accurate methods for the flow rate measurement are available, the method suggested in this work is advantageous over other methods due to its simplicity for practical applications in the petroleum industry.

  3. The One-Water Hydrologic Flow Model - The next generation in fully integrated hydrologic simulation software

    Science.gov (United States)

    Boyce, S. E.; Hanson, R. T.

    2015-12-01

    The One-Water Hydrologic Flow Model (MF-OWHM) is a MODFLOW-based integrated hydrologic flow model 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. MF-OWHM fully links the movement and use of groundwater, surface water, and imported water for consumption by agriculture and natural vegetation on the landscape, and for potable and other uses within a supply-and-demand framework. MF-OWHM is based on the Farm Process for MODFLOW-2005 combined with Local Grid Refinement, Streamflow Routing, Surface-water Routing Process, Seawater Intrusion, Riparian Evapotranspiration, and the Newton-Raphson solver. MF-OWHM also includes linkages for deformation-, flow-, and head-dependent flows; additional observation and parameter options for higher-order calibrations; and redesigned code for facilitation of self-updating models and faster simulation run times. The next version of MF-OWHM, currently under development, will include a new surface-water operations module that simulates dynamic reservoir operations, the conduit flow process for karst aquifers and leaky pipe networks, a new subsidence and aquifer compaction package, and additional features and enhancements to enable more integration and cross communication between traditional MODFLOW packages. By retaining and tracking the water within the hydrosphere, MF-OWHM accounts for "all of the water everywhere and all of the time." This philosophy provides more confidence in the water accounting by the scientific community and provides the public a foundation needed to address wider classes of problems such as evaluation of conjunctive-use alternatives and sustainability analysis, including potential adaptation and mitigation strategies, and best management practices. By Scott E. Boyce and Randall T. Hanson

  4. Hydraulic Transport Across Hydrophilic and Hydrophobic Nanopores: Flow Experiments with Water and n-Hexane

    CERN Document Server

    Gruener, Simon; Greulich, Stefanie; Busch, Mark; Huber, Patrick

    2015-01-01

    We experimentally explore pressure-driven flow of water and n-hexane across nanoporous silica (Vycor glass monoliths with 7 or 10 nm pore diameters, respectively) as a function of temperature and surface functionalization (native and silanized glass surfaces). Hydraulic flow rates are measured by applying hydrostatic pressures via inert gases (argon and helium, pressurized up to 70 bar) on the upstream side in a capacitor-based membrane permeability setup. For the native, hydrophilic silica walls, the measured hydraulic permeabilities can be quantitatively accounted for by bulk fluidity provided we assume a sticking boundary layer, i.e. a negative velocity slip length of molecular dimensions. The thickness of this boundary layer is discussed with regard to previous capillarity-driven flow experiments (spontaneous imbibition) and with regard to velocity slippage at the pore walls resulting from dissolved gas. Water flow across the silanized, hydrophobic nanopores is blocked up to a hydrostatic pressure of at l...

  5. Numerical investigation of cavitating flow behind the cone of a poppet valve in water hydraulic system

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Computational Fluid Dynamics (CFD) simulations of cavitating flow th rough water hydraulic poppet valves were performed using advanced RNG k-eps ilon turbulence model. The flow was turbulent, incompressible and unsteady, for Reyno lds numbers greater than 43 000. The working fluid was water, and the structure o f the valve was simplified as a two dimensional axisymmetric geometrical model. Flow field visualization was numerically achieved. The effects of inlet velocity , outlet pressure, opening size as well as poppet angle on cavitation intensity in the poppet valve were numerically investigated. Experimental flow visualization was conducted to capture cavitation images near the orifice in the poppet valve with 30° poppet angle using high speed video camera. The binary cavitating flo w field distribution obtained from digital processing of the original cavitation i mage showed a good agreement with the numerical result.

  6. Nanedi Vallis: Sustained Water Flow? - High Resolution Image

    Science.gov (United States)

    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 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 89A32), 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.

  7. Ground water stratification and delivery of nitrate to an incised stream under varying flow conditions.

    Science.gov (United States)

    Böhlke, J K; O'Connell, Michael E; Prestegaard, Karen L

    2007-01-01

    Ground water processes affecting seasonal variations of surface water nitrate concentrations were investigated in an incised first-order stream in an agricultural watershed with a riparian forest in the coastal plain of Maryland. Aquifer characteristics including sediment stratigraphy, geochemistry, and hydraulic properties were examined in combination with chemical and isotopic analyses of ground water, macropore discharge, and stream water. The ground water flow system exhibits vertical stratification of hydraulic properties and redox conditions, with sub-horizontal boundaries that extend beneath the field and adjacent riparian forest. Below the minimum water table position, ground water age gradients indicate low recharge rates (2-5 cm yr(-1)) and long residence times (years to decades), whereas the transient ground water wedge between the maximum and minimum water table positions has a relatively short residence time (months to years), partly because of an upward increase in hydraulic conductivity. Oxygen reduction and denitrification in recharging ground waters are coupled with pyrite oxidation near the minimum water table elevation in a mottled weathering zone in Tertiary marine glauconitic sediments. The incised stream had high nitrate concentrations during high flow conditions when much of the ground water was transmitted rapidly across the riparian zone in a shallow oxic aquifer wedge with abundant outflow macropores, and low nitrate concentrations during low flow conditions when the oxic wedge was smaller and stream discharge was dominated by upwelling from the deeper denitrified parts of the aquifer. Results from this and similar studies illustrate the importance of near-stream geomorphology and subsurface geology as controls of riparian zone function and delivery of nitrate to streams in agricultural watersheds.

  8. Comparability of Slack Water and Lagrangian Flow Respirometry Methods for Community Metabolic Measurements

    Science.gov (United States)

    Shaw, Emily C.; Phinn, Stuart R.; Tilbrook, Bronte; Steven, Andy

    2014-01-01

    Coral reef calcification is predicted to decline as a result of ocean acidification and other anthropogenic stressors. The majority of studies predicting declines based on in situ relationships between environmental parameters and net community calcification rate have been location-specific, preventing accurate predictions for coral reefs globally. In this study, net community calcification and production were measured on a coral reef flat at One Tree Island, Great Barrier Reef, using Lagrangian flow respirometry and slack water methods. Net community calcification, daytime net photosynthesis and nighttime respiration were higher under the flow respirometry method, likely due to increased water flow relative to the slack water method. The two methods also varied in the degrees to which they were influenced by potential measurement uncertainties. The difference in the results from these two commonly used methods implies that some of the location-specific differences in coral reef community metabolism may be due to differences in measurement methods. PMID:25426626

  9. Comparability of slack water and Lagrangian flow respirometry methods for community metabolic measurements.

    Directory of Open Access Journals (Sweden)

    Emily C Shaw

    Full Text Available Coral reef calcification is predicted to decline as a result of ocean acidification and other anthropogenic stressors. The majority of studies predicting declines based on in situ relationships between environmental parameters and net community calcification rate have been location-specific, preventing accurate predictions for coral reefs globally. In this study, net community calcification and production were measured on a coral reef flat at One Tree Island, Great Barrier Reef, using Lagrangian flow respirometry and slack water methods. Net community calcification, daytime net photosynthesis and nighttime respiration were higher under the flow respirometry method, likely due to increased water flow relative to the slack water method. The two methods also varied in the degrees to which they were influenced by potential measurement uncertainties. The difference in the results from these two commonly used methods implies that some of the location-specific differences in coral reef community metabolism may be due to differences in measurement methods.

  10. A modified Rusanov scheme for shallow water equations with topography and two phase flows

    Science.gov (United States)

    Mohamed, Kamel; Benkhaldoun, F.

    2016-06-01

    In this work, we introduce a finite volume method for numerical simulation of shallow water equations with source terms in one and two space dimensions, and one-pressure model of two-phase flows in one space dimension. The proposed method is composed of two steps. The first, called predictor step, depends on a local parameter allowing to control the numerical diffusion. A strategy based on limiters theory enables to control this parameter. The second step recovers the conservation equation. The scheme can thus be turned to order 1 in the regions where the flow has a strong variation, and order 2 in the regions where the flow is regular. The numerical scheme is applied to several test cases in one and two space dimensions. This scheme demonstrates its well-balanced property, and that it is an efficient and accurate approach for solving shallow water equations with and without source terms, and water faucet problem.

  11. Theoretical study of motion of small spherical air bubbles in a uniform shear flow of water

    Energy Technology Data Exchange (ETDEWEB)

    Mehdi, Syed Murtuza [Mechatronics Engineering, Jeju National University, Jeju (Korea, Republic of); Kim, Sin [School of Energy Systems Engineering, Chung-Ang University, Seoul (Korea, Republic of)

    2015-02-15

    A simple Couette flow velocity profile with an appropriate correlation for the free terminal rise velocity of a single bubble in a quiescent liquid can produce reliable results for the trajectories of small spherical air bubbles in a low-viscosity liquid (water) provided the liquid remains under uniform shear flow. Comparison of the model adopted in this paper with published results has been accomplished. Based on this study it has also been found that the lift coefficient in water is higher than its typical value in a high-viscosity liquid and therefore a modified correlation for the lift coefficient in a uniform shear flow of water within the regime of the Eoetvoes number 0:305 ≤ Eo ≤ 1:22 is also presented.

  12. Documentation of finite-difference model for simulation of three-dimensional ground-water flow

    Science.gov (United States)

    Trescott, Peter C.; Larson, S.P.

    1976-01-01

    User experience has indicated that the documentation of the model of three-dimensional ground-water flow (Trescott and Larson, 1975) should be expanded. This supplement is intended to fulfill that need. The original report emphasized the theory of the strongly implicit procedure, instructions for using the groundwater-flow model, and practical considerations for application. (See also W76-02962 and W76-13085) (Woodard-USGS)

  13. Physiological plasticity to water flow habitat in the damselfish, Acanthochromis polyacanthus: linking phenotype to performance.

    Directory of Open Access Journals (Sweden)

    Sandra A Binning

    Full Text Available The relationships among animal form, function and performance are complex, and vary across environments. Therefore, it can be difficult to identify morphological and/or physiological traits responsible for enhancing performance in a given habitat. In fishes, differences in swimming performance across water flow gradients are related to morphological variation among and within species. However, physiological traits related to performance have been less well studied. We experimentally reared juvenile damselfish, Acanthochromis polyacanthus, under different water flow regimes to test 1 whether aspects of swimming physiology and morphology show plastic responses to water flow, 2 whether trait divergence correlates with swimming performance and 3 whether flow environment relates to performance differences observed in wild fish. We found that maximum metabolic rate, aerobic scope and blood haematocrit were higher in wave-reared fish compared to fish reared in low water flow. However, pectoral fin shape, which tends to correlate with sustained swimming performance, did not differ between rearing treatments or collection sites. Maximum metabolic rate was the best overall predictor of individual swimming performance; fin shape and fish total length were 3.3 and 3.7 times less likely than maximum metabolic rate to explain differences in critical swimming speed. Performance differences induced in fish reared in different flow environments were less pronounced than in wild fish but similar in direction. Our results suggest that exposure to water motion induces plastic physiological changes which enhance swimming performance in A. polyacanthus. Thus, functional relationships between fish morphology and performance across flow habitats should also consider differences in physiology.

  14. Water Flow Testing and Unsteady Pressure Analysis of a Two-Bladed Liquid Oxidizer Pump Inducer

    Science.gov (United States)

    Schwarz, Jordan B.; Mulder, Andrew; Zoladz, Thomas

    2011-01-01

    The unsteady fluid dynamic performance of a cavitating two-bladed oxidizer turbopump inducer was characterized through sub-scale water flow testing. While testing a novel inlet duct design that included a cavitation suppression groove, unusual high-frequency pressure oscillations were observed. With potential implications for inducer blade loads, these high-frequency components were analyzed extensively in order to understand their origins and impacts to blade loading. Water flow testing provides a technique to determine pump performance without the costs and hazards associated with handling cryogenic propellants. Water has a similar density and Reynolds number to liquid oxygen. In a 70%-scale water flow test, the inducer-only pump performance was evaluated. Over a range of flow rates, the pump inlet pressure was gradually reduced, causing the flow to cavitate near the pump inducer. A nominal, smooth inducer inlet was tested, followed by an inlet duct with a circumferential groove designed to suppress cavitation. A subsequent 52%-scale water flow test in another facility evaluated the combined inducer-impeller pump performance. With the nominal inlet design, the inducer showed traditional cavitation and surge characteristics. Significant bearing loads were created by large side loads on the inducer during synchronous cavitation. The grooved inlet successfully mitigated these loads by greatly reducing synchronous cavitation, however high-frequency pressure oscillations were observed over a range of frequencies. Analytical signal processing techniques showed these oscillations to be created by a rotating, multi-celled train of pressure pulses, and subsequent CFD analysis suggested that such pulses could be created by the interaction of rotating inducer blades with fluid trapped in a cavitation suppression groove. Despite their relatively low amplitude, these high-frequency pressure oscillations posed a design concern due to their sensitivity to flow conditions and

  15. Use of a ground-water flow model with particle tracking to evaluate ground-water vulnerability, Clark County, Washington

    Science.gov (United States)

    Snyder, D.T.; Wilkinson, J.M.; Orzol, L.L.

    1996-01-01

    A ground-water flow model was used in conjunction with particle tracking to evaluate ground-water vulnerability in Clark County, Washington. Using the particle-tracking program, particles were placed in every cell of the flow model (about 60,000 particles) and tracked backwards in time and space upgradient along flow paths to their recharge points. A new computer program was developed that interfaces the results from a particle-tracking program with a geographic information system (GIS). The GIS was used to display and analyze the particle-tracking results. Ground-water vulnerability was evaluated by selecting parts of the ground-water flow system and combining the results with ancillary information stored in the GIS to determine recharge areas, characteristics of recharge areas, downgradient impact of land use at recharge areas, and age of ground water. Maps of the recharge areas for each hydrogeologic unit illustrate the presence of local, intermediate, or regional ground-water flow systems and emphasize the three-dimensional nature of the ground-water flow system in Clark County. Maps of the recharge points for each hydrogeologic unit were overlaid with maps depicting aquifer sensitivity as determined by DRASTIC (a measure of the pollution potential of ground water, based on the intrinsic characteristics of the near-surface unsaturated and saturated zones) and recharge from on-site waste-disposal systems. A large number of recharge areas were identified, particularly in southern Clark County, that have a high aquifer sensitivity, coincide with areas of recharge from on-site waste-disposal systems, or both. Using the GIS, the characteristics of the recharge areas were related to the downgradient parts of the ground-water system that will eventually receive flow that has recharged through these areas. The aquifer sensitivity, as indicated by DRASTIC, of the recharge areas for downgradient parts of the flow system was mapped for each hydrogeologic unit. A number of

  16. Effect of air on water capillary flow in silica nanochannels

    DEFF Research Database (Denmark)

    Zambrano, Harvey; Walther, Jens Honore; Oyarzua, Elton

    2013-01-01

    Capillarity is a classical topic in fluid dynamics. The fundamental relationship between capillarity and surface tension is solidly established. Nevertheless, capillarity is an active research area especially as the miniaturization of devices is reaching the molecular scale. Currently, with the f......Capillarity is a classical topic in fluid dynamics. The fundamental relationship between capillarity and surface tension is solidly established. Nevertheless, capillarity is an active research area especially as the miniaturization of devices is reaching the molecular scale. Currently......, with the fabrication of microsystems integrated by nanochannels, a thorough understanding of the transport of fluids in nanoconfinement is required for a successful operation of the functional parts of such devices. In this work, Molecular Dynamics simulations are conducted to study the spontaneous imbibition of water...

  17. An assembly model for simulation of large-scale ground water flow and transport.

    Science.gov (United States)

    Huang, Junqi; Christ, John A; Goltz, Mark N

    2008-01-01

    When managing large-scale ground water contamination problems, it is often necessary to model flow and transport using finely discretized domains--for instance (1) to simulate flow and transport near a contamination source area or in the area where a remediation technology is being implemented; (2) to account for small-scale heterogeneities; (3) to represent ground water-surface water interactions; or (4) some combination of these scenarios. A model with a large domain and fine-grid resolution will need extensive computing resources. In this work, a domain decomposition-based assembly model implemented in a parallel computing environment is developed, which will allow efficient simulation of large-scale ground water flow and transport problems using domain-wide grid refinement. The method employs common ground water flow (MODFLOW) and transport (RT3D) simulators, enabling the solution of almost all commonly encountered ground water flow and transport problems. The basic approach partitions a large model domain into any number of subdomains. Parallel processors are used to solve the model equations within each subdomain. Schwarz iteration is applied to match the flow solution at the subdomain boundaries. For the transport model, an extended numerical array is implemented to permit the exchange of dispersive and advective flux information across subdomain boundaries. The model is verified using a conventional single-domain model. Model simulations demonstrate that the proposed model operated in a parallel computing environment can result in considerable savings in computer run times (between 50% and 80%) compared with conventional modeling approaches and may be used to simulate grid discretizations that were formerly intractable.

  18. Behavior of CO2/water flow in porous media for CO2 geological storage.

    Science.gov (United States)

    Jiang, Lanlan; Yu, Minghao; Liu, Yu; Yang, Mingjun; Zhang, Yi; Xue, Ziqiu; Suekane, Tetsuya; Song, Yongchen

    2017-04-01

    A clear understanding of two-phase fluid flow properties in porous media is of importance to CO2 geological storage. The study visually measured the immiscible and miscible displacement of water by CO2 using MRI (magnetic resonance imaging), and investigated the factor influencing the displacement process in porous media which were filled with quartz glass beads. For immiscible displacement at slow flow rates, the MR signal intensity of images increased because of CO2 dissolution; before the dissolution phenomenon became inconspicuous at flow rate of 0.8mLmin(-1). For miscible displacement, the MR signal intensity decreased gradually independent of flow rates, because supercritical CO2 and water became miscible in the beginning of CO2 injection. CO2 channeling or fingering phenomena were more obviously observed with lower permeable porous media. Capillary force decreases with increasing particle size, which would increase permeability and allow CO2 and water to invade into small pore spaces more easily. The study also showed CO2 flow patterns were dominated by dimensionless capillary number, changing from capillary finger to stable flow. The relative permeability curve was calculated using Brooks-Corey model, while the results showed the relative permeability of CO2 slightly decreases with the increase of capillary number.

  19. Determination of flow rates of oil, water and gas in pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Roach, G.J.; Watt, J.S.; Zastawny, H.W. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), Lucas Heights, NSW (Australia). Div. of Mineral Physics

    1993-12-31

    This paper describes a multiphase flow meter developed by CSIRO for determining of the flow rates of oil, water and gas in high pressure pipelines, and the results of a trial of this flow meter on an offshore oil platform. Two gamma-ray transmission gauges are mounted about a pipeline carrying the full flow of oil, water and gas. The flow rates are determined by combining single energy gamma-ray transmission measurements which determine the mass per unit area of fluids in the gamma-ray beam as a function of time, dual energy gamma-ray transmission (DUET) which determine the approximate mass fraction of oil in the liquids, cross-correlation of gamma-ray transmission measurements, with one gauge upstream of the other, which determines flow velocity, pressure and temperature measurements, and knowledge of the specific gravities of oil and (salt) water, and solubility of the gas in the liquids, all as a function of pressure and temperature. 3 figs.

  20. Linkages Among Water Vapor Flows, Food Production, and Terrestrial Ecosystem Services

    Directory of Open Access Journals (Sweden)

    Johan Rockström

    1999-12-01

    Full Text Available Global freshwater assessments have not addressed the linkages among water vapor flows, agricultural food production, and terrestrial ecosystem services. We perform the first bottom-up estimate of continental water vapor flows, subdivided into the major terrestrial biomes, and arrive at a total continental water vapor flow of 70,000 km3/yr (ranging from 56,000 to 84,000 km3/yr. Of this flow, 90% is attributed to forests, including woodlands (40,000 km3/yr, wetlands (1400 km3/yr, grasslands (15,100 km3/yr, and croplands (6800 km3/yr. These terrestrial biomes sustain society with essential welfare-supporting ecosystem services, including food production. By analyzing the freshwater requirements of an increasing demand for food in the year 2025, we discover a critical trade-off between flows of water vapor for food production and for other welfare-supporting ecosystem services. To reduce the risk of unintentional welfare losses, this trade-off must become embedded in intentional ecohydrological landscape management.

  1. Energy Harvesting from Fluid Flow in Water Pipelines for Smart Metering Applications

    Science.gov (United States)

    Hoffmann, D.; Willmann, A.; Göpfert, R.; Becker, P.; Folkmer, B.; Manoli, Y.

    2013-12-01

    In this paper a rotational, radial-flux energy harvester incorporating a three-phase generation principle is presented for converting energy from water flow in domestic water pipelines. The energy harvester together with a power management circuit and energy storage is used to power a smart metering system installed underground making it independent from external power supplies or depleting batteries. The design of the radial-flux energy harvester is adapted to the housing of a conventional mechanical water flow meter enabling the use of standard components such as housing and impeller. The energy harvester is able to generate up to 720 mW when using a flow rate of 20 l/min (fully opened water tab). A minimum flow rate of 3 l/min is required to get the harvester started. In this case a power output of 2 mW is achievable. By further design optimization of the mechanical structure including the impeller and magnetic circuit the threshold flow rate can be further reduced.

  2. An investigation of channel flow with a smooth air-water interface

    Science.gov (United States)

    Madad, Reza; Elsnab, John; Chin, Cheng; Klewicki, Joseph; Marusic, Ivan

    2015-06-01

    Experiments and numerical simulation are used to investigate fully developed laminar and turbulent channel flow with an air-water interface as the lower boundary condition. Laser Doppler velocimetry measurements of streamwise and wall-normal velocity components are made over a range of Reynolds number based upon channel height and bulk velocity from 1100 to 4300, which encompasses the laminar, transitional and low Reynolds numbers turbulent regimes. The results show that the airflow statistics near the stationary wall are not significantly altered by the air-water moving interface and reflect those found in channel flows. The mean statistics on the water interface side largely exhibit results similar to simulated Poiseuille-Couette flow (PCF) with a solid moving wall. For second-order statistics, however, the simulation and experimental results show some discrepancies near the moving water surface, suggesting that a full two-phase simulation is required. A momentum and energy transport tubes analysis is investigated for laminar and turbulent PCFs. This analysis builds upon the classical notion of a streamtube and indicates that part of the energy from the pressure gradient is transported towards the stationary wall and is dissipated as heat inside the energy tubes, while the remainder is transmitted to the moving wall. For the experiments, the airflow energy is transmitted towards the water to overcome the drag force and drive the water forward; therefore, the amount of energy transferred to the water is higher than the energy transferred to a solid moving wall.

  3. Water tunnel visualization of the vortex flows of the F-15

    Science.gov (United States)

    Lorincz, D. J.; Friend, E. L.

    1979-01-01

    Flow visualization studies were conducted in a diagnostic water tunnel to provide details of the wing, glove, and forebody vortex flow fields of the F-15 aircraft over a range of angles of attack and sideslip. Both the formation and breakdown of the vortex flow as a function of angle of attack and sideslip are detailed for the basic aircraft configuration. Additional tests showed that the wing upper surface vortex flows were sensitive to variations in an inlet mass flow ratio and an inlet cowl deflection angle. Two lengthened forebodies, one with a modified cross-sectional shape, were tested in addition to the basic forebody. Asymmetric forebody vortices were observed at zero sideslip and high angles of attack on each forebody. A large nose boom was added to each of the three forebodies, and it was observed that the turbulent wake shed from the boom disrupted the forebody vortices.

  4. Applications of Continuous-Flow Photochemistry in Organic Synthesis, Material Science, and Water Treatment.

    Science.gov (United States)

    Cambié, Dario; Bottecchia, Cecilia; Straathof, Natan J W; Hessel, Volker; Noël, Timothy

    2016-09-14

    Continuous-flow photochemistry in microreactors receives a lot of attention from researchers in academia and industry as this technology provides reduced reaction times, higher selectivities, straightforward scalability, and the possibility to safely use hazardous intermediates and gaseous reactants. In this review, an up-to-date overview is given of photochemical transformations in continuous-flow reactors, including applications in organic synthesis, material science, and water treatment. In addition, the advantages of continuous-flow photochemistry are pointed out and a thorough comparison with batch processing is presented.

  5. A Preliminary Study on 1D Numerical Experiment of Water Debris Flow in Gully

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    In order to improve and enhance the numerical modeling methods and its application on debris flow problems,a preliminary study has been proposed in accordance with the corrected water-sediment numerical model on the premise of revised resistance and sediment capacity equations.Firstly,an overview the recent re- search achievements on numerical simulation of debris flow has been conducted,the results shown that a gener- al numerical model for debris flow can not be existed at all because the complex rheol...

  6. Water Quality and Environmental Flow Management in Rapidly Urbanizing Shenzhen Estuary Area, China

    Science.gov (United States)

    Qin, H.; Su, Q.

    2011-12-01

    Shenzhen estuary is located in a rapidly urbanizing coastal region of Southeast China, and forms the administrative border between mainland China and Hong Kong. It receives the waters of the Shenzhen River, where it enters the Deep Bay. The estuary has great ecological importance with the internationally recognized mangrove wetlands, which provides a habitat for some rare and endangered waterfowl and migratory birds.Water quality in the esturay has deteriorated not only due to increasing wastewater discharges from domestic and industrial sources, but also as a consequence of decreasing base environmental flow during rapid urbanization in the Shenzhen River catchment since 1980s. Measures to improve water quality of the estuary include not only reducing pollutant inputs by intercepting wastewater, but also increasing environmental flow by reusing reclaimed wastewater or withdrawing nearshore seawater into the river. However, salinity alternation due to flow increase is deemed to have impacts on the mangrove wetland ecosystem. In this paper, Environmental Fluid Dynamics Code (EFDC) is used to simulate hydrodynamics, salinity, and water quality condition in the Shenzhen estuary. After calibration and validation, the model is used to evaluate effects of various control measures on water quality improvement and salinity alteration in the estuary. The results indicate that implementing different measures independently does not reach the goals of water quality improvement; furthermore, increasing environmental flow by importing nearshore seawater may greatly increase the salinity in the Shenzhen River, destroy the fresh ecosystem of the river and have non-negligible impacts on the mangrove wetland ecosystem. Based on the effectiveness and impacts of the measures, an integrated measure, which combine pollutant loads reduction and environmental flow increase by reusing reclaimed wastewater, is proposed to achieve water environmental sustainability in the study area.

  7. Depressurization and two-phase flow of water containing high levels of dissolved nitrogen gas

    Science.gov (United States)

    Simoneau, R. J.

    1981-01-01

    Depressurization of water containing various concentrations of dissolved nitrogen gas was studied. In a nonflow depressurization experiment, water with very high nitrogen content was depressurized at rates from 0.09 to 0.50 MPa per second and a metastable behavior which was a strong function of the depressurization rate was observed. Flow experiments were performed in an axisymmetric, converging diverging nozzle, a two dimensional, converging nozzle with glass sidewalls, and a sharp edge orifice. The converging diverging nozzle exhibited choked flow behavior even at nitrogen concentration levels as low as 4 percent of the saturation level. The flow rates were independent of concentration level. Flow in the two dimensional, converging, visual nozzle appeared to have a sufficient pressure drop at the throat to cause nitrogen to come out of solution, but choking occurred further downstream. The orifice flow motion pictures showed considerable oscillation downstream of the orifice and parallel to the flow. Nitrogen bubbles appeared in the flow at back pressures as high as 3.28 MPa, and the level at which bubbles were no longer visible was a function of nitrogen concentration.

  8. Fire Source Accessibility of Water Mist Fire Suppression Improvement through Flow Method Control

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Jun Ho; Kim, Hyeong Taek; Kim, Yun Jung; Park, Mun Hee [KHNP CRI, Daejeon (Korea, Republic of)

    2013-10-15

    Recently, nuclear power plants set CO{sub 2} fire suppression system. However it is hard to establish and to maintain and it also has difficulties performing function test. Therefore, it needs to develop a new fire suppression system to replace the existing CO{sub 2} fire suppression systems in nuclear power plant. In fact, already, there exist alternatives - gas fire suppression system or clean fire extinguishing agent, but it is hard to apply because it requires a highly complicated plan. However, water mist fire suppression system which has both water system and gas system uses small amount of water and droplet, so it is excellent at oxygen displacement and more suitable for nuclear power plant because it can avoid second damage caused by fire fighting water. This paper explains about enclosure effect of water mist fire suppression. And it suggests a study direction about water mist fire source approach improvement and enclosure effect improvement, using flow method control of ventilation system. Water mist fire suppression can be influenced by various variable. And flow and direction of ventilation system are important variable. Expectations of the plan for more fire source ventilation system is as in the following. It enhances enclosure effects of water mists, so it improves extinguish performance. Also the same effect as a inert gas injection causes can be achieved. Lastly, it is considered that combustible accessibility of water mists will increase because of descending air currents.

  9. Global network of embodied water flow by systems input-output simulation

    Institute of Scientific and Technical Information of China (English)

    Zhanming CHEN; Guoqian CHEN; Xiaohua XIA; Shiyun XU

    2012-01-01

    The global water resources network is simulated in the present work for the latest target year with statistical data available and with the most detailed data disaggregation.A top-down approach of systems inputoutput simulation is employed to track the embodied water flows associated with economic flows for the globalized economy in 2004.The numerical simulation provides a database of embodied water intensities for all economic commodities from 4928 producers,based on which the differences between direct and indirect water using efficiencies at the global scale are discussed.The direct and embodied water uses are analyzed at continental level.Besides,the commodity demand in terms of monetary expenditure and the water demand in terms of embodied water use are compared for the world as well as for three major water using regions,i.e.,India,China,and the United States.Results show that food product contributes to a significant fraction for water demand,despite the value varies significantly with respect to the economic status of region.

  10. Computer-Aided Analysis of Flow in Water Pipe Networks after a Seismic Event

    Directory of Open Access Journals (Sweden)

    Won-Hee Kang

    2017-01-01

    Full Text Available This paper proposes a framework for a reliability-based flow analysis for a water pipe network after an earthquake. For the first part of the framework, we propose to use a modeling procedure for multiple leaks and breaks in the water pipe segments of a network that has been damaged by an earthquake. For the second part, we propose an efficient system-level probabilistic flow analysis process that integrates the matrix-based system reliability (MSR formulation and the branch-and-bound method. This process probabilistically predicts flow quantities by considering system-level damage scenarios consisting of combinations of leaks and breaks in network pipes and significantly reduces the computational cost by sequentially prioritizing the system states according to their likelihoods and by using the branch-and-bound method to select their partial sets. The proposed framework is illustrated and demonstrated by examining two example water pipe networks that have been subjected to a seismic event. These two examples consist of 11 and 20 pipe segments, respectively, and are computationally modeled considering their available topological, material, and mechanical properties. Considering different earthquake scenarios and the resulting multiple leaks and breaks in the water pipe segments, the water flows in the segments are estimated in a computationally efficient manner.

  11. Numerical Investigation of the Water Droplet Transport in a PEM Fuel Cell with Serpentine Flow Channel

    Directory of Open Access Journals (Sweden)

    Bittagopal Mondal

    2016-01-01

    Full Text Available The serpentine flow channel can be considered as one of the most common and practical channel layouts for a polymer electrolyte membrane fuel cell (PEMFC since it ensures an effective and efficient removal of water produced in a cell with acceptable parasitic load. Water management is one of the key issues to improve the cell performance since at low operating temperatures in PEMFC, water vapor condensation starts easily and accumulates the liquid water droplet within the flow channels, thus affecting the chemical reactions and reducing the fuel cell performance. In this article, a comprehensive three dimensional numerical simulation is carried out to understand the water droplet mobility in a serpentine gas flow channel for a wide range of surface properties, inlet air velocities, droplet positions (center or off-center, bottom or top and droplet sizes by deploying a finite volume based methodology. The liquid-gas interface is tracked following the volume-of-fluid (VOF method. The droplet transport is found to be greatly influenced by the surface wettability properties, inlet velocities, number of droplets emerged and initial droplet positions. Super hydrophobic surface property is not always preferable for designing the gas flow channels. It depends upon the inlet velocity conditions, droplet positions, number of droplets and surface properties.

  12. Factors influencing arsenic and nitrate removal from drinking water in a continuous flow electrocoagulation (EC) process

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, N. Sanjeev [Civil Engineering Department, IIT Kharagpur, Kharagpur 721302 (India); Goel, Sudha, E-mail: sudhagoel@civil.iitkgp.ernet.in [Civil Engineering Department, IIT Kharagpur, Kharagpur 721302 (India)

    2010-01-15

    An experimental study was conducted under continuous flow conditions to evaluate some of the factors influencing contaminant removal by electrocoagulation (EC). A bench-scale simulation of drinking water treatment was done by adding a filtration column after a rectangular EC reactor. Contaminant removal efficiency was determined for voltages ranging from 10 to 25 V and a comparative study was done with distilled water and tap water for two contaminants: nitrate and arsenic(V). Maximum removal efficiency was 84% for nitrate at 25 V and 75% for arsenic(V) at 20 V. No significant difference in contaminant removal was observed in tap water versus distilled water. Increase in initial As(V) concentration from 1 ppm to 2 ppm resulted in a 10% increase in removal efficiency. Turbidity in the EC reactor effluent was 52 NTU and had to be filtered to achieve acceptable levels of final turbidity (5 NTU) at steady-state. The flow regime in the continuous flow reactor was also evaluated in a tracer study to determine whether it is a plug flow reactor (PFR) or constantly stirred tank reactor (CSTR) and the results show that this reactor was close to an ideal CSTR, i.e., it was fairly well-mixed.

  13. Grass Cover Influences Hydrophysical Parameters and Heterogeneity of Water Flow in a Sandy Soil

    Institute of Scientific and Technical Information of China (English)

    L. LICHNER; D. J. ELDRIDGE; K. SCHACHT; N. ZHUKOVA; L. HOLKO; M. (S)(I)R; J. PECHO

    2011-01-01

    Vegetation cover has a major effect on water flow in soils.Two sites,separated by distance of about 50 m,were selected to quantify the influence of grass cover on hydrophysical parameters and heterogeneity of water flow in a sandy soil emerging during a heavy rain following a long hot,dry period.A control soil (pure sand) with limited impact of vegetation or organic matter was obtained by sampling at 50 cm depth beneath a glade area,and a grassland soil was covered in a 10 cm thick humic layer and colonised by grasses.The persistence of water repellency was measured using the water drop penetration time test,sorptivity and unsaturated hydraulic conductivity using a mini disk infiltrometer,and saturated hydraulic conductivity using a double-ring infiltrometer.Dye tracer experiments were used to assess the heterogeneity of water flow,and both the modified method for estimating effective cross section and an original method for assessing the degree of preferential flow were used to quantify this heterogeneity from the images of dyed soil profiles.Most hydrophysical parameters were substantially different between the two surfaces.The grassland soil had an index of water repellency about 10 times that of pure sand and the persistence of water repellency almost 350 times that of pure sand.Water and ethanol sorptivities in the grassland soil were 7% and 43%,respectively,of those of the pure sand.Hydraulic conductivity and saturated hydraulic conductivities in the grassland soil were 5% and 16% of those of the pure sand,respectively.Dye tracer experiments revealed a stable flow with "air-draining" condition in pure sand and well-developed preferential flow in grassland soil,corresponding to individual grass tussocks and small micro-depressions.The grassland soil was substantially more water repellent and had 3 times the degree of preferential flow compared to pure sand.The results of this study reinforce our view that the consequences of any change in climate

  14. In-pipe water quality monitoring in water supply systems under steady and unsteady state flow conditions: a quantitative assessment.

    Science.gov (United States)

    Aisopou, Angeliki; Stoianov, Ivan; Graham, Nigel J D

    2012-01-01

    Monitoring the quality of drinking water from the treatment plant to the consumers tap is critical to ensure compliance with national standards and/or WHO guideline levels. There are a number of processes and factors affecting the water quality during transmission and distribution which are little understood. A significant obstacle for gaining a detailed knowledge of various physical and chemical processes and the effect of the hydraulic conditions on the water quality deterioration within water supply systems is the lack of reliable and low-cost (both capital and O & M) water quality sensors for continuous monitoring. This paper has two objectives. The first one is to present a detailed evaluation of the performance of a novel in-pipe multi-parameter sensor probe for reagent- and membrane-free continuous water quality monitoring in water supply systems. The second objective is to describe the results from experimental research which was conducted to acquire continuous water quality and high-frequency hydraulic data for the quantitative assessment of the water quality changes occurring under steady and unsteady-state flow conditions. The laboratory and field evaluation of the multi-parameter sensor probe showed that the sensors have a rapid dynamic response, average repeatability and unreliable accuracy. The uncertainties in the sensor data present significant challenges for the analysis and interpretation of the acquired data and their use for water quality modelling, decision support and control in operational systems. Notwithstanding these uncertainties, the unique data sets acquired from transmission and distribution systems demonstrated the deleterious effect of unsteady state flow conditions on various water quality parameters. These studies demonstrate: (i) the significant impact of the unsteady-state hydraulic conditions on the disinfectant residual, turbidity and colour caused by the re-suspension of sediments, scouring of biofilms and tubercles from the

  15. The Discuss of the Formula of Flow Loss and Water Using Coefficient on Seepage Proofed Channel

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    On the basis of the analysis about present water resource situation in China ,the disadvantage of the for mula of flow loss and water using coefficient on anti-seep channel which have been applying in channel de sign and water saving irrigation administration will be indicated in the paper. The characteristics of that the loss of conveying water is changeable with the flow changing have been take into account in the new formula. The formula is validated by the example of middle permeable channel (A = 1.90,m = 0.40). The calculate re sult is more precision. Also some formula has been given,they can be referred to the worker of the irrigation administration.

  16. Influence of submarine morphology on bottom water flow across the western Ross Sea continental margin

    Science.gov (United States)

    Davey, F.J.; Jacobs, S.S.

    2007-01-01

    Multibeam sonar bathymetry documents a lack of significant channels crossing outer continental shelf and slope of the western Ross Sea. This indicates that movement of bottom water across the shelf break into the deep ocean in this area is mainly by laminar or sheet flow. Subtle, ~20 m deep and up to 1000 m wide channels extend down the continental slope, into tributary drainage patterns on the upper rise, and then major erosional submarine canyons. These down-slope channels may have been formed by episodic pulses of rapid down slope water flow, some recorded on bottom current meters, or by sub-ice melt water erosion from an icesheet grounded at the margin. Narrow, mostly linear furrows on the continental shelf thought to be caused by iceberg scouring are randomly oriented, have widths generally less than 400 m and depths less than 30m, and extend to water depths in excess of 600 m.

  17. Reverse motion characteristics of water-vapor mixture in supercavitating flow around a hydrofoil

    Institute of Scientific and Technical Information of China (English)

    李向宾; 李楠; 王国玉; 张敏弟

    2016-01-01

    The supercavitation has attracted a growing interest because of its potential for high-speed vehicle maneuvering and drag reduction. To better understand the reverse flow characteristics of a water-vapor mixture in supercavitating flows around a hydrofoil, a numerical simulation is conducted using a unified supercavitation model, which combines a modified RNGk-e turbulence model and a cavitation one. By comparing the related experimental results, the reverse motion of the water-vapor mixture is found in the cavitation area in all supercavitation stages. The inverse pressure gradient leads to reverse pressure fluctuations in the cavity, followed by the reverse motion of the water-vapor two-phase interface. Compared with the water-vapor mixture area at the back of the cavity, the pressure in the vapor area is inversely and slowly reduced,a higher-pressure gradient occurs near the cavity boundary.

  18. Relationships between basic soils-engineering equations and basic ground-water flow equations

    Science.gov (United States)

    Jorgensen, Donald G.

    1980-01-01

    The many varied though related terms developed by ground-water hydrologists and by soils engineers are useful to each discipline, but their differences in terminology hinder the use of related information in interdisciplinary studies. Equations for the Terzaghi theory of consolidation and equations for ground-water flow are identical under specific conditions. A combination of the two sets of equations relates porosity to void ratio and relates the modulus of elasticity to the coefficient of compressibility, coefficient of volume compressibility, compression index, coefficient of consolidation, specific storage, and ultimate compaction. Also, transient ground-water flow is related to coefficient of consolidation, rate of soil compaction, and hydraulic conductivity. Examples show that soils-engineering data and concepts are useful to solution of problems in ground-water hydrology.

  19. Shrub morpho-types as indicator for the water flow energy - Tivoli travertine case (Central Italy)

    Science.gov (United States)

    Erthal, Marcelle Marques; Capezzuoli, Enrico; Mancini, Alessandro; Claes, Hannes; Soete, Jeroen; Swennen, Rudy

    2017-01-01

    Travertines from Tivoli area (Central Italy) possess abundant shrub-like fabrics that are laterally continuous over hundreds of square meters. They occur dominantly in horizontal layers with aggradational and progradational stacking patterns. Their fabrics and morphologies are remarkably similar to the shrubs lithotypes reported in literature for the Pre-Salt reservoirs, offshore Brazil and Angola, with huge oil accumulations. Petrographic and micro-computer tomography analyses allowed the identification of six shrub morpho-types (i.e., narrow dendriform, wide dendriform, fili dendriform, arborescent, arbustiform and pustular). Dendriform shrubs are the most common lithotype in Tivoli area, and three different subtypes could be distinguished according to the arrangement of their branches. The shrubs consist largely of peloidal micritic aggregates engulfed in spar calcite, ranging in average from 1 to 3 cm in height. The shrubs are interpreted to have developed in very shallow extensive waterlogged slightly inclined flat areas, changing laterally into a slope system with crusts as the main lithotype. Changes in the hydrodynamic conditions with episodes of stagnancy influenced the shrub morpho-types making them very variegated. Shrub morphologies likely reflect specific (micro-) environments that are controlled by water flow rates, evaporation and microbial activity. The latter processes influenced shrub fabric and morphology. Under high flow conditions, CO2 degassing is the main process leading to carbonate precipitation. Consequently, denser and tightly packed morphologies will precipitate, composing mainly the crust lithotype. In this scenario microbes are less dominant. Dendriform shrubs, with narrow, wide and fili morphologies are interpreted to occur in moderate to low energy water flows. Narrow dendriform shrubs reflect faster flowing conditions, with decreasing impact of flow on the morphological aspects from wide dendriform shrubs to fili dendriform shrubs

  20. The role of event water, a rapid shallow flow component, and catchment size in summer stormflow

    Science.gov (United States)

    Brown, V.A.; McDonnell, Jeffery J.; Burns, Douglas A.; Kendall, C.

    1999-01-01

    Seven nested headwater catchments (8 to 161 ha) were monitored during five summer rain events to evaluate storm runoff components and the effect of catchment size on water sources. Two-component isotopic hydrograph separation showed that event-water contributions near the time of peakflow ranged from 49% to 62% in the 7 catchments during the highest intensity event. The proportion of event water in stormflow was greater than could be accounted for by direct precipitation onto saturated areas. DOC concentrations in stormflow were strongly correlated with stream 18O composition. Bivariate mixing diagrams indicated that the large event water contributions were likely derived from flow through the soil O-horizon. Results from two-tracer, three-component hydrograph separations showed that the throughfall and O-horizon soil-water components together could account for the estimated contributions of event water to stormflow. End-member mixing analysis confirmed these results. Estimated event-water contributions were inversely related to catchment size, but the relation was significant for only the event with greatest rainfall intensity. Our results suggest that perched, shallow subsurface flow provides a substantial contribution to summer stormflow in these small catchments, but the relative contribution of this component decreases with catchment size.Seven nested headwater catchments (8 to 161 ha) were monitored during five summer rain events to evaluate storm runoff components and the effect of catchment size on water sources. Two-component isotopic hydrograph separation showed that event-water contributions near the time of peakflow ranged from 49% to 62% in the 7 catchments during the highest intensity event. The proportion of event water in stormflow was greater than could be accounted for by direct precipitation onto saturated areas. DOC concentrations in stormflow were strongly correlated with stream 18O composition. Bivariate mixing diagrams indicated that the

  1. Coupled equations for transient water flow, heat flow, and deformation in hydrogeological systems

    Indian Academy of Sciences (India)

    T N Narasimhan

    2006-04-01

    Hydrogeological systems are earth systems influenced by water.Their behaviors are governed by interacting processes,including flow of fluids,deformation of porous materials,chemical reactions, and transport of matter and energy.Here,coupling among three of these processes is considered: flow of water,heat,and deformation,each of which is represented by a diffusion-type of partial differential equation.One side of the diffusion-type equation relates to motion of matter or energy, while the other relates to temporal changes of state variables at a given location.The coupling arises from processes that govern motion as well as those that relate to change of state.In this work, attention is devoted to coupling arising from changes in state.Partial derivatives of equations of state constitute the capacitance terms of diffusion-type equations.Of the many partial derivatives that are mathematically possible in physical systems characterized by several variables,only a few are physically signi ficant.Because the state variables are related to each other through an equation of state,the partial derivatives must collectively satisfy a closure criterion.This framework offers a systematic way of developing the coupled set of equations that govern hydrogeological systems involving the flow of water,heat,and deformation.Such systems are described in terms of four variables,and the associated partial derivatives.The physical import of these derivatives are discussed,followed by a description of partial derivatives that are of practical interest.These partial derivatives are then used as the basis to develop a set of coupled equations.A brief discussion is presented on coupled equations from a perspective of energy optimization.

  2. On calculation of a steam-water flow in a geothermal well

    Science.gov (United States)

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

    2013-08-01

    Approaches to calculation of a steam-water flow in a geothermal well are considered. For hydraulic applications, a WELL-4 model of a steam-water well is developed. Data obtained using this model are compared with experimental data and also with calculations by similar models including the well-known HOLA model. The capacity of the A-2 well in the Mutnovskoe flash-steam field (Kamchatka half-island, Russia) after planned reconstruction is predicted.

  3. Larval green and white sturgeon swimming performance in relation to water-diversion flows

    OpenAIRE

    Verhille, Christine E.; Poletto, Jamilynn B.; Cocherell, Dennis E.; DeCourten, Bethany; Baird, Sarah; Joseph J Cech; Fangue, Nann A.

    2014-01-01

    Little is known of the swimming capacities of larval sturgeons, despite global population declines in many species due in part to fragmentation of their spawning and rearing habitats by man-made water-diversion structures. Larval green (Acipenser medirostris) and white sturgeon (Acipenser transmontanus) inhabit the highly altered Sacramento–San Joaquin watershed, making them logical species to examine vulnerability to entrainment by altered water flows. The risk of larval sturgeon entrainment...

  4. Simulating Water-Quality Trends in Public-Supply Wells in Transient Flow Systems

    OpenAIRE

    Jeffrey Starn, J; Green, Christopher T.; Hinkle, Stephen R; Bagtzoglou, Amvrossios C.; Stolp, Bernard J

    2014-01-01

    Models need not be complex to be useful. An existing groundwater-flow model of Salt Lake Valley, Utah, was adapted for use with convolution-based advective particle tracking to explain broad spatial trends in dissolved solids. This model supports the hypothesis that water produced from wells is increasingly younger with higher proportions of surface sources as pumping changes in the basin over time. At individual wells, however, predicting specific water-quality changes remains challenging. T...

  5. Experimental study on the flow regimes and pressure gradients of air-oil-water three-phase flow in horizontal pipes.

    Science.gov (United States)

    Al-Hadhrami, Luai M; Shaahid, S M; Tunde, Lukman O; Al-Sarkhi, A

    2014-01-01

    An experimental investigation has been carried out to study the flow regimes and pressure gradients of air-oil-water three-phase flows in 2.25 ID horizontal pipe at different flow conditions. The effects of water cuts, liquid and gas velocities on flow patterns and pressure gradients have been studied. The experiments have been conducted at 20 °C using low viscosity Safrasol D80 oil, tap water and air. Superficial water and oil velocities were varied from 0.3 m/s to 3 m/s and air velocity varied from 0.29 m/s to 52.5 m/s to cover wide range of flow patterns. The experiments were performed for 10% to 90% water cuts. The flow patterns were observed and recorded using high speed video camera while the pressure drops were measured using pressure transducers and U-tube manometers. The flow patterns show strong dependence on water fraction, gas velocities, and liquid velocities. The observed flow patterns are stratified (smooth and wavy), elongated bubble, slug, dispersed bubble, and annular flow patterns. The pressure gradients have been found to increase with the increase in gas flow rates. Also, for a given superficial gas velocity, the pressure gradients increased with the increase in the superficial liquid velocity. The pressure gradient first increases and then decreases with increasing water cut. In general, phase inversion was observed with increase in the water cut. The experimental results have been compared with the existing unified Model and a good agreement has been noticed.

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

    Science.gov (United States)

    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.

  7. Flow pattern, void fraction and pressure drop of two-phase air-water flow in a horizontal circular micro-channel

    Energy Technology Data Exchange (ETDEWEB)

    Saisorn, Sira [Energy Division, The Joint Graduate School of Energy and Environment (JGSEE), King Mongkut' s University of Technology Thonburi, Bangmod, Bangkok 10140 (Thailand); Wongwises, Somchai [Fluid Mechanics, Thermal Engineering and Multiphase Flow Research Laboratory (FUTURE), Department of Mechanical Engineering, King Mongkut' s University of Technology Thonburi, Bangmod, Bangkok 10140 (Thailand)

    2008-01-15

    Adiabatic two-phase air-water flow characteristics, including the two-phase flow pattern as well as the void fraction and two-phase frictional pressure drop, in a circular micro-channel are experimentally studied. A fused silica channel, 320 mm long, with an inside diameter of 0.53 mm is used as the test section. The test runs are done at superficial velocity of gas and liquid ranging between 0.37-16 and 0.005-3.04 m/s, respectively. The flow pattern map is developed from the observed flow patterns i.e. slug flow, throat-annular flow, churn flow and annular-rivulet flow. The flow pattern map is compared with those of other researchers obtained from different working fluids. The present single-phase experiments also show that there are no significant differences in the data from the use of air or nitrogen gas, and water or de-ionized water. The void fraction data obtained by image analysis tends to correspond with the homogeneous flow model. The two-phase pressure drops are also used to calculate the frictional multiplier. The multiplier data show a dependence on flow pattern as well as mass flux. A new correlation of two-phase frictional multiplier is also proposed for practical application. (author)

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

    Science.gov (United States)

    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

  9. The Physiological and Biochemical Mechanisms Providing the Increased Constitutive Cold Resistance in the Potato Plants, Expressing the Yeast SUC2 Gene Encoding Apoplastic Invertase

    Directory of Open Access Journals (Sweden)

    A.N. Deryabin

    2016-05-01

    Full Text Available The expression of heterologous genes in plants is an effective method to improve our understanding of plant resistance mechanisms. The purpose of this work was to investigate the involvement of cell-wall invertase and apoplastic sugars into constitutive cold resistance of potato (Solanum tuberosum L., cv. Dйsirйe plants, which expressed the yeast SUC2 gene encoding apoplastic invertase. WT-plants of a potato served as the control. The increase in the essential cell-wall invertase activity in the leaves of transformed plants indicates significant changes in the cellular carbohydrate metabolism and regulatory function of this enzyme. The activity of yeast invertase changed the composition of intracellular sugars in the leaves of the transformed potato plant. The total content of sugars (sucrose, glucose, fructose in the leaves and apoplast was higher in the transformants, in comparison by WT-plants. Our data indicate higher constitutive resistance of transformants to severe hypothermia conditions compared to WT-plants. This fact allows us to consider cell-wall invertase as a enzyme of carbohydrate metabolism playing an important regulatory role in the metabolic signaling upon forming increased plant resistance to low temperature. Thus, the potato line with the integrated SUC2 gene is a convenient tool to study the role of the apoplastic invertase and the products of its activity during growth, development and formation constitutive resistance to hypothermia.

  10. Impact and Mitigation of Nutrient Pollution and Overland Water Flow Change on the Florida Everglades, USA

    Directory of Open Access Journals (Sweden)

    Kristin Schade-Poole

    2016-09-01

    Full Text Available A subtropical watershed and wetland covering nearly 47,000 km2 in the southeastern United States, the Florida Everglades is a degraded, human-dominated environment. As a unique and important ecosystem, the Everglades provide a variety of important environmental services for society and nature. Over the past century and a half, anthropogenic actions have severely impacted the Everglades by disrupting the natural water flow and causing water pollution. As a result, the native flora and fauna have been displaced, important habitats have been lost, invasive species have become prevalent, and water contaminant concentrations have increased. Accelerating efforts are being made towards preserving the Everglades ecosystem by restoring water flow and improving water quality. To explore this complex and important aquatic ecosystem, we critically review the relevant environmental history, major terrestrial and aquatic characteristics and dynamics, engineered changes to water flow, major sources and impacts of nutrient pollution, trends in system response to pollution and mitigation actions, and recent regulatory efforts driving restoration.

  11. Performance characteristics of two-phase-flow turbo-expanders used in water-cooled chillers

    Energy Technology Data Exchange (ETDEWEB)

    Brasz, J.J. [United Technologies Carrier, New York, NY (United States)

    1999-07-01

    Use of two-phase-flow throttle loss recovery devices in water-cooled chillers requires satisfactory part-load operation. This paper describes the results of two-phase-flow impulse turbine testing and the data reduction of the test results into a two-phase-flow turbine off-design performance model. It was found that the main parameter controlling the efficiency of two-phase-flow turbine is the ratio of the nozzle spouting velocity to the rotor speed. The turbine mass flow rate is mainly controlled by inlet subcooling of the entering liquid. The strong sensitivity of turbine mass flow rate on inlet subcooling allows the use of a conventional float valve upstream of the turbine as an effective means of controlling the turbine during part-load operation. For a well-designed two-phase-flow turbine, nozzle spouting velocity and therefore turbine efficiency is hardly affected by the amount of inlet subcooling. Also, capacity can be substantially reduced by a reduction in the amount of inlet subcooling entering the turbine nozzles. Hence, turbine part-load efficiency equals its full-load efficiency over a wide range of flow rates using this control concept. (Author)

  12. The value of long-term monitoring in the development of ground-water-flow models

    Science.gov (United States)

    Feinstein, Daniel T.; Hart, David J.; Krohelski, James T.

    2004-01-01

    As environmental issues have come to the forefront of public concern, so has the awareness of the importance of ground water in the overall water cycle and as a source of the Nation’s drinking water. Heightened interest has spawned a host of scientific enterprises (Taylor and Alley, 2001). Some activities are directed toward collection of water-level data and related information to monitor the physical and chemical state of the resource. Other activities are directed at interpretive studies undertaken, for example, to optimize the location of new water-supply wells or to protect rivers and lakes fed by ground water. An important type of interpretive study is the computer ground-water-flow model that inte- grates field data in a mathematical framework. Long-term, systematic collection of hydro- logic data is crucial to the construction and testing of ground-water models so that they can reproduce the evolution of flow systems and forecast future conditions. 

  13. Hydrogeology and simulation of ground-water flow, Picatinny Arsenal and vicinity, Morris County, New Jersey

    Science.gov (United States)

    Voronin, L.M.; Rice, D.E.

    1996-01-01

    Ground-water flow in glacial sediments and bedrock at Picatinny Arsenal, N.J., was simulated by use of a three-dimensional finite-difference ground- water-flow model. The modeled area includes a 4.3-square-mile area that extends from Picatinny Lake to the Rockaway River. Most of the study area is bounded by the natural hydrologic boundaries of the ground-water system. eophysical logs, lithologic logs, particle-size data, and core data from selected wells and surface geophysical data were analyzed to define the hydrogeologic framework. Hydrogeologic sections and thickness maps define six permeable and three low-permeability layers that are represented in the model as aquifers and confining units, respectively. Hydrologic data incorporated in the model include a rate of recharge from precipitation of 22 inches per year, estimated from long-term precipitation records and estimates of evapotranspiration. Additional recharge from infiltration along valleys was estimated from measured discharge of springs along the adjacent valley walls and from estimates of runoff from upland drainage that flows to the valley floor. Horizontal and vertical hydraulic conductivities of permeable and low-permeability layers were estimated from examination of aquifer-test data, gamma-ray logs, borehole cuttings, and previously published data. Horizontal hydraulic conductivities in glacial sediments range from 10 to 380 feet per day. Vertical hydraulic conductivities of the low-permeability layers range from 0.01 to 0.7 feet per day. The model was calibrated by simulating steady-state conditions during 1989-93 and by closely matching simulated and measured ground-water levels, vertical ground-water-head differences, and streamflow gain and loss. Simulated steady-state potentiometric- surface maps produced for the six permeable layers indicate that ground water in the unconfined material within Picatinny Arsenal flows predominantly toward the center of the valley, where it discharges to Green

  14. Cerberus Fossae and Elysium Planitia Lavas, Mars: Source Vents, Flow Rates, Edifice Styles and Water Interactions

    Science.gov (United States)

    Sakimoto, S. E. H.; Gregg, T. K. P.

    2004-01-01

    The Cerberus Fossae and Elysium Planitia regions have been suggested as some of the youngest martian surfaces since the Viking mission, although there was doubt whether the origins were predominantly volcanic or fluvial. The Mars Global Surveyor and Mars Odyssey Missions have shown that the region is certainly young in terms of the topographic preservation and the youthful crater counts (e.g. in the tens to a few hundred million yrs.). Numerous authors have shown that fluvial and volcanic features share common flow paths and vent systems, and that there is evidence for some interaction between the lava flows and underlying volatiles as well as the use by lavas and water of the same vent system. Given the youthful age and possible water-volcanism interaction environment, we'd like constraints on water and volcanic flux rates and interactions. Here, we model ranges of volcanic flow rates where we can well-constrain them, and consider the modest flow rate results results in context with local eruption styles, and track vent locations, edifice volumes, and flow sources and data.

  15. Nanoparticle transport in water-unsaturated porous media: effects of solution ionic strength and flow rate

    Science.gov (United States)

    Prédélus, Dieuseul; Lassabatere, Laurent; Louis, Cédric; Gehan, Hélène; Brichart, Thomas; Winiarski, Thierry; Angulo-Jaramillo, Rafael

    2017-03-01

    This paper presents the influence of ionic strength and flow on nanoparticle (NP) retention rate in an unsaturated calcareous medium, originating from a heterogeneous glaciofluvial deposit of the region of Lyon (France). Laboratory columns 10 cm in diameter and 30 cm in length were used. Silica nanoparticles (Au-SiO2-FluoNPs), with hydrodynamic diameter ranging from 50 to 60 nm and labeled with fluorescein derivatives, were used to simulate particle transport, and bromide was used to characterize flow. Three flow rates and five different ionic strengths were tested. The transfer model based on fractionation of water into mobile and immobile fractions was coupled with the attachment/detachment model to fit NPs breakthrough curves. The results show that increasing flow velocity induces a decrease in nanoparticle retention, probably as the result of several physical but also geochemical factors. The results show that NPs retention increases with ionic strength. However, an inversion of retention occurs for ionic strength >5.10-2 M, which has been scarcely observed in previous studies. The measure of zeta potential and DLVO calculations show that NPs may sorb on both solid-water and air-water interfaces. NPs size distribution shows the potential for nanoparticle agglomeration mostly at low pH, leading to entrapment in the soil pores. These mechanisms are highly sensitive to both hydrodynamic and geochemical conditions, which explains their high sensitivity to flow rates and ionic strength.

  16. A Hydrological Concept including Lateral Water Flow Compatible with the Biogeochemical Model ForSAFE

    Directory of Open Access Journals (Sweden)

    Giuliana Zanchi

    2016-03-01

    Full Text Available The study presents a hydrology concept developed to include lateral water flow in the biogeochemical model ForSAFE. The hydrology concept was evaluated against data collected at Svartberget in the Vindeln Research Forest in Northern Sweden. The results show that the new concept allows simulation of a saturated and an unsaturated zone in the soil as well as water flow that reaches the stream comparable to measurements. The most relevant differences compared to streamflow measurements are that the model simulates a higher base flow in winter and lower flow peaks after snowmelt. These differences are mainly caused by the assumptions made to regulate the percolation at the bottom of the simulated soil columns. The capability for simulating lateral flows and a saturated zone in ForSAFE can greatly improve the simulation of chemical exchange in the soil and export of elements from the soil to watercourses. Such a model can help improve the understanding of how environmental changes in the forest landscape will influence chemical loads to surface waters.

  17. An Efficient Multiple-Dimensional Finite Element Solution for Water Flow in Variably Saturated Soils

    Institute of Scientific and Technical Information of China (English)

    QI Xue-bin; ZHANG Xiao-xian; PANG Hong-bin

    2008-01-01

    Multiple-dimensional water flow in variably saturated soils plays an important role in ecological systems such as irrigation and water uptake by plant roots;its quantitative description is usually based on the Richards' equation.Because of the nonlinearity of the Richards' equation and the complexity of natural soils,most practical simulations rely on numerical solutions with the nonlinearity solved by iterations.The commonly used iterations for solving the nonlinearity are Picard and Newton methods with the former converging at first-order rate and the later at second-order rate.A recent theoretical analysis by the authors,however,revealed that for solving the diffusive flow,the classical Picard method is actually a chord-Newton method,converging at a rate faster than first order;its linear convergence rate is due to the treatment of the gravity term.To improve computational efficiency,a similar chord-Newton method as for solving the diffusive term was proposed to solve the gravity term.Testing examples for one-dimensional flow showed significant improvement.The core of this method is to produce a diagonally dominant matrix in the linear system so as to improve the iteration-toiteration stability and hence the convergence.In this paper,we develop a similar method for multiple-dimensional flow and compare its performance with the classical Picard and Newton methods for water flow in soils characterised by a wide range of van Genuchten parameters.

  18. Slip divergence of water flow in graphene nanochannels: the role of chirality

    DEFF Research Database (Denmark)

    Wagemann, Enrique; Oyarzua, Elton; Walther, Jens Honore

    2017-01-01

    , for an optimal design of nanofluidic devices, a comprehensive understanding of the slippage in a water flow confined between graphene walls is important. In nanoconfinement, experimental and computational studies have found the slip length to increase nonlinearly when the shear rate is larger than a critical...

  19. Flow resistance of vegetated oblique weir-like obstacles during high water stages

    NARCIS (Netherlands)

    Ali, S.; Uijttewaal, W.S.J.

    2011-01-01

    At high water stages obstacles in the floodplains of a river contribute to the flow resistance. In particular the elevated vegetated parts are expected to play an important role. The objective of this study is to estimate and parameterize the form drag due to vegetated oblique weir-like obstacles. A

  20. Iron oxidation kinetics and phosphate immobilization along the flow-path from groundwater into surface water.

    NARCIS (Netherlands)

    Grift, van der B.; Rozemeijer, J.C.; Griffioen, J.; Velde, van der Y.

    2014-01-01

    The retention of phosphorus in surface waters though co-precipitation of phosphate with Fe-oxyhydroxides during exfiltration of anaerobic Fe(II) rich groundwater is not well understood. We developed an experimental field set-up to study Fe(II) oxidation and 5 P immobilization along the flow-path fro

  1. Iron oxidation kinetics and phosphate immobilization along the flow-path from groundwater into surface water

    NARCIS (Netherlands)

    van der Grift, B.; Rozemeijer, J. C.; Griffioen, J.; van der Velde, Y.

    2014-01-01

    The retention of phosphorus in surface waters though co-precipitation of phosphate with Fe-oxyhydroxides during exfiltration of anaerobic Fe(II) rich groundwater is not well understood. We developed an experimental field set-up to study Fe(II) oxidation and P immobilization along the flow-path from

  2. Water repellency under coniferous and deciduous forest - Experimental assessment and impact on overland flow

    NARCIS (Netherlands)

    Butzen, Verena; Seeger, Manuel; Marruedo, Amaia; Jonge, de Lianne; Wengel, René; Ries, Johannes B.; Casper, Markus C.

    2015-01-01

    Current climate change makes it necessary to gain a deeper understanding of the runoff generation processes in Central European forests. A changing climate might affect soil water repellency (SWR) which can be seen as an import trigger for overland flow generation in forested areas. In this study

  3. Parametric Studies on Buoyancy Induced Flow through Circular Pipes in Solar water heating system

    Directory of Open Access Journals (Sweden)

    Dr. S. V. Prayagi

    2011-01-01

    Full Text Available Solar energy is the primary source of energy for our planet. The average solar energy reaching the earth in the tropical zone is about 1kWh/m2 giving approximately 5 to 10 kWh/m2 per day. Increased utilization of solar energy in India would result in all around benefits, both in term of cleaner environment and monetary gain.The energy from the sun can be used for various purposes such as water heating, water distillation, refrigeration, drying, power generation etc. The present work deals with solar water heating system in particular. Performance of the solar collectors can be determined using the famous Hottel-Whillier-Bliss equation [1]. The analysis is simple for the forced convection situation, where the flow rate is artificially maintained constant to a desired value and the heat transfer coefficient can easily be predicted using the information available in the literature. However the natural convection situation it is very difficult to analyze as appropriate correlations for predicting the values of induced mass flow rate due to thermosiphon effect and the associated heat transfer coefficient are not available. The aim of the present investigation, therefore, is to establish correlations for heat transfer and flow characteristics for the buoyancy induced flow through inclined tubes in case of solar water heating system in particular. Considering the complexity of the problem, experimental approach is preferred. In order to produce required data, experiments were performed using inclined tubes of various lengths, diameters, inclinations, and different heat inputs.

  4. A coupled model tree genetic algorithm scheme for flow and water quality predictions in watersheds

    Science.gov (United States)

    Preis, Ami; Ostfeld, Avi

    2008-02-01

    SummaryThe rapid advance in information processing systems along with the increasing data availability have directed research towards the development of intelligent systems that evolve models of natural phenomena automatically. This is the discipline of data driven modeling which is the study of algorithms that improve automatically through experience. Applications of data driven modeling range from data mining schemes that discover general rules in large data sets, to information filtering systems that automatically learn users' interests. This study presents a data driven modeling algorithm for flow and water quality load predictions in watersheds. The methodology is comprised of a coupled model tree-genetic algorithm scheme. The model tree predicts flow and water quality constituents while the genetic algorithm is employed for calibrating the model tree parameters. The methodology is demonstrated through base runs and sensitivity analysis for daily flow and water quality load predictions on a watershed in northern Israel. The method produced close fits in most cases, but was limited in estimating the peak flows and water quality loads.

  5. Thermal ground water flow systems in the thrust zone in southeastern Idaho

    Energy Technology Data Exchange (ETDEWEB)

    Ralston, D.R.

    1983-05-01

    The results of a regional study of thermal and non-thermal ground water flow systems in the thrust zone of southern Idaho and western Wyoming are presented. The study involved hydrogeologic and hydrochemical data collection and interpretation. Particular emphasis was placed on analyzing the role that thrust zones play in controlling the movement of thermal and non-thermal fluids.

  6. Water flow induced transport of Pseudomonas fluorescens cells through soil columns as affected by inoculant treatment

    NARCIS (Netherlands)

    Hekman, W.E.; Heijnen, C.E.; Trevors, J.T.; Elsas, van J.D.

    1994-01-01

    Water flow induced transport of Pseudomonas fluorescens cells through soil columns was measured as affected by the inoculant treatment. Bacterial cells were introduced into the topsoil of columns, either encapsulated in alginate beads of different types or mixed with bentonite clay in concentrations

  7. Experimental Investigation of the Interaction between Rising Bubbles and Swirling Water Flow

    Directory of Open Access Journals (Sweden)

    Tomomi Uchiyama

    2014-01-01

    Full Text Available This study experimentally investigates the interaction between rising bubbles and swirling water flow imposed around the central (vertical axis of a bubble plume in a cylindrical water tank. Small air bubbles are successively released from the bottom of the tank to generate a bubble plume, and a stirring disc at the bottom of the tank is rotated to impose a swirling water flow around the central axis of the bubble plume. The bubbles disperse further with the increasing rotational speed ω of the stirring disc. Some bubbles shift toward the central axis of the swirling flow when ω is high. The nondimensional swirling velocity of water reduces with increasing bubble flow rate when ω is lower than a certain value. However, it is less affected by the bubbles when ω is higher. The precessional amplitude for the upper end of the vortex core increases due to the presence of the bubbles. With increasing ω, the nondimensional precessional velocity decreases, and the bubble effect also reduces.

  8. Concepts and dimensionality in modeling unsaturated water flow and solute transport

    NARCIS (Netherlands)

    Dam, van J.C.; Rooij, de G.H.; Heinen, M.; Stagnitti, F.

    2004-01-01

    Many environmental studies require accurate simulation of waterand solute fluxes in the unsaturated zone. This paper evaluatesone- and multi-dimensional approaches for soil water flow as wellas different spreading mechanisms to model solute behavior atdifferent scales. For quantification of soil wat

  9. Flow Regimes of Air-Water Counterflow Through Cross Corrugated Parallel Plates

    Energy Technology Data Exchange (ETDEWEB)

    de Almeida, V.F.

    2000-06-07

    Heretofore unknown flow regimes of air-water counterflow through a pair of transparent vertical parallel cross corrugated plates were observed via high-speed video. Air flows upward driven by pressure gradient and water, downward driven by gravity. The crimp geometry of the corrugations was drawn from typical corrugated sheets used as filling material in modern structured packed towers. Four regimes were featured, namely, rivulet, bicontinuous, flooding fronts, and flooding waves. It is conceivable that the regimes observed might constitute the basis for understanding how gas and liquid phases contend for available space in the interstices of structured packings in packed towers. Flow regime transitions were expressed in terms of liquid load (liquid superficial velocity) and gas flow factor parameters commonly used in pressure drop and capacity curves. We have carefully examined the range of parameters equivalent to the ill-understood high-liquid-flow operation in packed towers. More importantly, our findings should prove valuable in validating improved first-principles modeling of gas-liquid flows in these industrially important devices.

  10. Water fact sheet, history of landslides and debris flows at Mount Rainier

    Science.gov (United States)

    Scott, K.M.; Vallance, J.W.

    1993-01-01

    Many landslides and debris flows have originated from Mount Rainier since the retreat of glaciers from Puget Sound about 10,000 years ago. The recurrent instability is due to several factors--height of the steep-sided volcanic cone, frequent volcanic activity, continuous weakening of rock by steam and hot, chemical-laden water, and exposure of unstable areas as the mountains glaciers have receded. The landslide scars and deposits tell a fascinating story of the changing shape of the volcano. Landslides occur when part of the volcano "collapses" or fails and slides away from the rest of the volcano. The failed mass rapidly breaks up into a jumble of disaggregated pieces that flow at high velocity like a fluid. Clay and water in the debris cause further change to a liquid slurry known as a debris flow or mudflow. Volcanic debris flows are also widely known by the Indonesian term "lahar." Although the largest debris flows at Rainier form from landslides, many smaller flows are caused by volcanic eruptions, intense rainfall, and glacial-outburst floods.

  11. Simulation of regional ground-water flow in the Upper Deschutes Basin, Oregon

    Science.gov (United States)

    Gannett, Marshall W.; Lite, Kenneth E.

    2004-01-01

    This report describes a numerical model that simulates regional ground-water flow in the upper Deschutes Basin of central Oregon. Ground water and surface water are intimately connected in the upper Deschutes Basin and most of the flow of the Deschutes River is supplied by ground water. Because of this connection, ground-water pumping and reduction of artificial recharge by lining leaking irrigation canals can reduce the amount of ground water discharging to streams and, consequently, streamflow. The model described in this report is intended to help water-management agencies and the public evaluate how the regional ground-water system and streamflow will respond to ground-water pumping, canal lining, drought, and other stresses. Ground-water flow is simulated in the model by the finite-difference method using MODFLOW and MODFLOWP. The finite-difference grid consists of 8 layers, 127 rows, and 87 columns. All major streams and most principal tributaries in the upper Deschutes Basin are included. Ground-water recharge from precipitation was estimated using a daily water-balance approach. Artificial recharge from leaking irrigation canals and on-farm losses was estimated from diversion and delivery records, seepage studies, and crop data. Ground-water pumpage for irrigation and public water supplies, and evapotranspiration are also included in the model. The model was calibrated to mean annual (1993-95) steady-state conditions using parameter-estimation techniques employing nonlinear regression. Fourteen hydraulic-conductivity parameters and two vertical conductance parameters were determined using nonlinear regression. Final parameter values are all within expected ranges. The general shape and slope of the simulated water-table surface and overall hydraulic-head distribution match the geometry determined from field measurements. The fitted standard deviation for hydraulic head is about 76 feet. The general magnitude and distribution of ground-water discharge to

  12. Water demand for ecosystem protection in rivers with hyper-concentrated sediment-laden flow

    Institute of Scientific and Technical Information of China (English)

    LUO Huaming; LI Tianhong; NI Jinren; WANG Yudong

    2004-01-01

    Sediment transport is one of the main concerns in a river system with hyper-concentrated flows. Therefore, the water use for sediment transport must be considered in study on the water demand for river ecosystem. The conventional methods for calculating the Minimum Water Demand for River Ecosystem (MWDRE) are not appropriate for rivers with high sediment concentration. This paper studied the MWDRE in wet season, dry season and the whole year under different water-and-sediment conditions in the Lower Yellow River, which is regarded as a typical river with sediment-laden flows. The characteristics of MWDRE in the river are analyzed. Firstly,the water demand for sediment transport (WDST) is much larger than the demands for other riverine functions, the WDST accounts for the absolute majority of the MWDRE.Secondly, in wet season when the WDST is satisfied, not only most of the annual incoming sediment can be transported downstream, but also the water demands for other river functions can be satisfied automatically, so that the MWDRE in wet season is identical to the WDST. Thirdly, in dry season, when the WDST is satisfied, the water demands for other river functions can also be satisfied, but the low sediment transport efficiency results in significant waste of water resources. According to these characteristics and aiming at decreasing sediment deposition in the riverbed and improving the utilization efficiency of water resources, hydrological engineering works can be used to regulate or control flow and sediment so that the sediment incoming in dry season can be accumulated and be transported downstream intensively and thus efficiently in wet season.

  13. Direction of ground-water flow and ground-water quality near a landfill in Falmouth, Massachusetts

    Science.gov (United States)

    Persky, J.H.

    1986-01-01

    A landfill in Falmouth, Massachusetts, is upgradient of a pond used for municipal water supply, but analysis of groundwater flow directions and groundwater quality indicates that leachate from the landfill does not threaten the municipal water supply. A network of water table observation wells was established, and water table altitudes were measured in these wells on several dates in 1981. Water quality analyses and specific conductance measurements were made on water samples from several wells in the vicinity of the landfill between October 1980 and April 1983. A water table altitude contour map of the area between the landfill and Long Pond for April 16-17, 1981, indicates that the direction of groundwater flow is primarily southwest from the landfill to Buzzards Bay. A similar map for September 2, 1981--a time at which the water table was unusually low--indicates the possibility of groundwater discharge to Long Pond from the landfill site. Groundwater quality beneath the landfill exceeded U.S. EPA water quality criteria for domestic water supply for manganese and total dissolved solids. Concentrations as high as 52 mg/L of nitrogen as ammonia and 4,500 micrograms/L (ug/L) of manganese were found. Concentrations of ammonia, manganese, calcium, potassium, and alkalinity exceeded local background levels by more than a factor of 100; specific-conductance levels and concentrations of hardness, barium, chloride, sodium, magnesium, iron, and strontium exceeded local background levels by more than a factor of 10; and cadmium concentrations exceeded local background levels by more than a factor of 5. Water quality analyses and field specific conductance measurements indicate the presence of a volume of leachate extending south-southwest from the landfill. Average chloride concentrations of landfill leachate, precipitation on the surface of Long Pond, and recharge from the remainder of the recharge area were 180, 3, and 9 mg/L, respectively. No significant degradation of

  14. Transient flow between aquifers and surface water: analytically derived field-scale hydraulic heads and fluxes

    Directory of Open Access Journals (Sweden)

    G. H. de Rooij

    2012-03-01

    Full Text Available The increasing importance of catchment-scale and basin-scale models of the hydrological cycle makes it desirable to have a simple, yet physically realistic model for lateral subsurface water flow. As a first building block towards such a model, analytical solutions are presented for horizontal groundwater flow to surface waters held at prescribed water levels for aquifers with parallel and radial flow. The solutions are valid for a wide array of initial and boundary conditions and additions or withdrawals of water, and can handle discharge into as well as lateral infiltration from the surface water. Expressions for the average hydraulic head, the flux to or from the surface water, and the aquifer-scale hydraulic conductivity are developed to provide output at the scale of the modelled system rather than just point-scale values. The upscaled conductivity is time-variant. It does not depend on the magnitude of the flux but is determined by medium properties as well as the external forcings that drive the flow. For the systems studied, with lateral travel distances not exceeding 10 m, the circular aquifers respond very differently from the infinite-strip aquifers. The modelled fluxes are sensitive to the magnitude of the storage coefficient. For phreatic aquifers a value of 0.2 is argued to be representative, but considerable variations are likely. The effect of varying distributions over the day of recharge damps out rapidly; a soil water model that can provide accurate daily totals is preferable over a less accurate model hat correctly estimates the timing of recharge peaks.

  15. A mathematical model for unsteady mixed flows in closed water pipes

    CERN Document Server

    Bourdarias, Christian; Gerbi, Stéphane

    2011-01-01

    We present the formal derivation of a new unidirectional model for unsteady mixed flows in non uniform closed water pipe. In the case of free surface incompressible flows, the \\FS-model is formally obtained, using formal asymptotic analysis, which is an extension to more classical shallow water models. In the same way, when the pipe is full, we propose the \\Pres-model, which describes the evolution of a compressible inviscid flow, close to gas dynamics equations in a nozzle. In order to cope the transition between a free surface state and a pressured (i.e. compressible) state, we propose a mixed model, the \\PFS-model, taking into account changes of section and slope variation.

  16. A mathematical model for unsteady mixed flows in closed water pipes

    Institute of Scientific and Technical Information of China (English)

    BOURDARIAS; Christian; ERSOY; Mehmet; GERBI; Stéphane

    2012-01-01

    We present the formal derivation of a new unidirectional model for unsteady mixed flows in nonuniform closed water pipes.In the case of free surface incompressible flows,the FS-model is formally obtained,using formal asymptotic analysis,which is an extension to more classical shallow water models.In the same way,when the pipe is full,we propose the P-model,which describes the evolution of a compressible inviscid flow,close to gas dynamics equations in a nozzle.In order to cope with the transition between a free surface state and a pressured(i.e.,compressible) state,we propose a mixed model,the PFS-model,taking into account changes of section and slope variation.

  17. Immiscible displacement of oil by water in a microchannel: asymmetric flow behavior and nonlinear stability analysis of core-annular flow.

    Science.gov (United States)

    Foroughi, Hooman; Abbasi, Alireza; Das, Kausik S; Kawaji, Masahiro

    2012-02-01

    The immiscible displacement of oil by water in a circular microchannel was investigated. A fused silica microchannel with an inner diameter of 250 μm and a length of 7 cm was initially filled with a viscous silicone oil. Only water then was injected into the channel. We describe our flow observations based on the two-dimensional images captured in the middle of the channel. The water finger displaced the oil and left an oil film on the channel wall. While the oil was being displaced at the core, the flow resistance decreased, which resulted in increases in water flow rate and inertia. Eventually, the water finger reached the channel exit and formed a core-annular flow pattern. The wavelength of the waves formed at the oil-water interface also increased with the increase in inertia. The initially symmetric interfacial waves became asymmetric with time. Also, the water core shifted from the center of the channel and left a thinner oil film on one side of the microchannel. Under all flow rates tested in this study, as long as the water was continuously injected, the water core was stable and no breakup into droplets was observed. We also discuss the flow stability based on nonlinear and linear stability analyses performed on the core-annular flow. Compared to the linear analysis, which ignores the inertia effects, the nonlinear analysis, which includes the inertia effects, predicts longer interfacial wavelengths by a factor of 1/sqrt[1-a(o)/2(We(w) + We(o)a(o)(2)/1-a(o)(2))] where We(w) and We(o) are the Weber numbers of the water and the oil phases, respectively, and a(o) is the unperturbed water core radius made dimensionless by the channel radius.

  18. Immiscible displacement of oil by water in a microchannel: Asymmetric flow behavior and nonlinear stability analysis of core-annular flow

    Science.gov (United States)

    Foroughi, Hooman; Abbasi, Alireza; Das, Kausik S.; Kawaji, Masahiro

    2012-02-01

    The immiscible displacement of oil by water in a circular microchannel was investigated. A fused silica microchannel with an inner diameter of 250 μm and a length of 7 cm was initially filled with a viscous silicone oil. Only water then was injected into the channel. We describe our flow observations based on the two-dimensional images captured in the middle of the channel. The water finger displaced the oil and left an oil film on the channel wall. While the oil was being displaced at the core, the flow resistance decreased, which resulted in increases in water flow rate and inertia. Eventually, the water finger reached the channel exit and formed a core-annular flow pattern. The wavelength of the waves formed at the oil-water interface also increased with the increase in inertia. The initially symmetric interfacial waves became asymmetric with time. Also, the water core shifted from the center of the channel and left a thinner oil film on one side of the microchannel. Under all flow rates tested in this study, as long as the water was continuously injected, the water core was stable and no breakup into droplets was observed. We also discuss the flow stability based on nonlinear and linear stability analyses performed on the core-annular flow. Compared to the linear analysis, which ignores the inertia effects, the nonlinear analysis, which includes the inertia effects, predicts longer interfacial wavelengths by a factor of (1)/(1-(ao)/(2)(Wew+Weo(ao2)/(1-ao2))) where Wew and Weo are the Weber numbers of the water and the oil phases, respectively, and ao is the unperturbed water core radius made dimensionless by the channel radius.

  19. Towards more spatially explicit assessments of virtual water flows: linking local water use and scarcity to global demand of Brazilian farming commodities

    Science.gov (United States)

    Flach, Rafaela; Ran, Ylva; Godar, Javier; Karlberg, Louise; Suavet, Clement

    2016-07-01

    Global consumption of farming commodities is an important driver of water demand in regions of production. This is the case in Brazil, which has emerged as one of the main producers of globally traded farming commodities. Traditional methods to assess environmental implications of this demand rely on international trade material flows at country resolution; we argue for the need of finer scales that capture spatial heterogeneity in environmental variables in the regions of production, and that account for differential sourcing within the borders of a country of production. To illustrate this, we obtain virtual water flows from Brazilian municipalities to countries of consumption, by allocating high-resolution water footprints of sugarcane and soy production to spatially-explicit material trade flows. We found that this approach results in differences of virtual water use estimations of over 20% when compared to approaches that disregard spatial heterogeneity in sourcing patterns, for three of the main consumers of the analysed crops. This discrepancy against methods using national resolution in trade flows is determined by national heterogeneity in water resources, and differential sourcing. To illustrate the practical implications of this approach, we relate virtual water flows to water stress, identifying where global demand for water coincides with high levels of water stress. For instance, the virtual water flows for Brazilian sugarcane sourced by China were disproportionally less associated to areas with higher water stress when compared to those of the EU, due to EU’s much higher reliance on sugarcane from water scarce areas in Northeast Brazil. Our findings indicate that the policy relevance of current assessments of virtual water flows that rely on trade data aggregated at the national level may be hampered, as they do not capture the spatial heterogeneity in water resources, water use and water management options.

  20. Ensemble kalman filtering to perform data assimilation with soil water content probes and pedotransfer functions in modeling water flow in variably saturated soils

    Science.gov (United States)

    Data from modern soil water contents probes can be used for data assimilation in soil water flow modeling, i.e. continual correction of the flow model performance based on observations. The ensemble Kalman filter appears to be an appropriate method for that. The method requires estimates of the unce...

  1. Flow Forecasting in Urban Drainage Systems using Deterministic Updating of Water Levels in Distributed Hydraulic Models

    DEFF Research Database (Denmark)

    Hansen, Lisbeth S.; Borup, Morten; Møller, A.;

    2011-01-01

    the performance of the updating procedure for flow forecasting. Measured water levels in combination with rain gauge input are used as basis for the evaluation. When compared to simulations without updating, the results show that it is possible to obtain an improvement in the 20 minute forecast of the water level...... to eliminate some of the unavoidable discrepancies between model and reality. The latter can partly be achieved by using the commercial tool MOUSE UPDATE, which is capable of inserting measured water levels from the system into the distributed, physically based MOUSE model. This study evaluates and documents...

  2. Flows induced by sorption on fibrous material in a two-layer oil-water system

    Science.gov (United States)

    Chaplina, T. O.; Chashechkin, Yu. D.; Stepanova, E. V.

    2016-09-01

    The processes of sorption on fibrous materials in the open elliptic cell filled with a two-layer oil-water liquid at rest are investigated experimentally. When the sorption efficiency dependent on the type of material proves to be reasonably high, large-scale flows are formed in the liquid. In this case, the uniformity of distribution of oil is violated and the free surface of the water is partially restored. The trajectories of motion of individual oil droplets on a released water surface are tracked, and the transfer rates are calculated in various phases of the process.

  3. Design and Analysis of Cross Flow Turbine for Micro Hydro Power Application using Sewerage Water

    OpenAIRE

    Muhammad Adil Khan; Saeed Badshah

    2014-01-01

    The objective of this study endeavor is to describe the design of an environment friendly captive micro hydel power plant at the sewerage treatment plant outlet fall at Lai Nallah located in I-9 Islamabad. It will use sewerage water of CDA as discharge water to run the turbine of the micro hydel power plant to generate electricity. The important phases of the project are to carry out survey for collection of data about hydrology, quantity of flow of water, fall head, geology and design of an ...

  4. EXPERIMENTAL STUDY OF EFFECTS OF OPERATING CONDITIONS ON THE FLOW CHARACTERISTICS OF WATER HYDRAULIC THROTTLE

    Institute of Scientific and Technical Information of China (English)

    Liu Yinshui; Nie Songlin; Zhu Yuquan; He Xiaofeng; Li Zhuangyun

    2004-01-01

    Experimental investigations are made on the effects of operating conditions on the flow characteristics of throttle when tap water is used as the working media. The researched throttles include cone poppet valve, ball valve, disc valve and dumping orifice. Operating condition includes poppet lift, working media, back pressure, medium temperature, etc. Because the vapourous pressure of water is much higher than that of oil, cavitation is easier to occur in water hydraulic elements and systems, so the effects of operating conditions on the cavitation characteristics of throttle are also researched.

  5. Dimensionless numbers used to characterize stratification in water tanks for discharging at low flow rates

    Energy Technology Data Exchange (ETDEWEB)

    Castell, A.; Medrano, M.; Sole, C.; Cabeza, L.F. [GREA Innovacio concurrent, Universitat de Lleida, Pere de Cabrera s/n, 25001 Lleida (Spain)

    2010-10-15

    The efficiency of thermal energy storage and solar collector systems is improved if the water tank is stratified. There are many parameters to characterize stratification but no work compares their suitability. This paper identifies the most used dimensionless numbers to characterize stratification in water tanks and studies their suitability. Experiments with different flow rates were done and the dimensionless numbers were determined. Richardson is the best number to define stratification in a water tank, while Mix number presents some problems and a bad behaviour. The other numbers do not clearly characterize stratification but can be useful combined with Richardson. (author)

  6. Apoplastic polyamine oxidation plays different roles in local responses of tobacco to infection by the necrotrophic fungus Sclerotinia sclerotiorum and the biotrophic bacterium Pseudomonas viridiflava.

    Science.gov (United States)

    Marina, María; Maiale, Santiago Javier; Rossi, Franco Rubén; Romero, Matías Fernando; Rivas, Elisa Isabel; Gárriz, Andrés; Ruiz, Oscar Adolfo; Pieckenstain, Fernando Luis

    2008-08-01

    The role of polyamine (PA) metabolism in tobacco (Nicotiana tabacum) defense against pathogens with contrasting pathogenic strategies was evaluated. Infection by the necrotrophic fungus Sclerotinia sclerotiorum resulted in increased arginine decarboxylase expression and activity in host tissues, as well as putrescine and spermine accumulation in leaf apoplast. Enhancement of leaf PA levels, either by using transgenic plants or infiltration with exogenous PAs, led to increased necrosis due to infection by S. sclerotiorum. Specific inhibition of diamine and PA oxidases attenuated the PA-induced enhancement of leaf necrosis during fungal infection. When tobacco responses to infection by the biotrophic bacterium Pseudomonas viridiflava were investigated, an increase of apoplastic spermine levels was detected. Enhancement of host PA levels by the above-described experimental approaches strongly decreased in planta bacterial growth, an effect that was blocked by a PA oxidase inhibitor. It can be concluded that accumulation and further oxidation of free PAs in the leaf apoplast of tobacco plants occurs in a similar, although not identical way during tobacco defense against infection by microorganisms with contrasting pathogenesis strategies. This response affects the pathogen's ability to colonize host tissues and results are detrimental for plant defense against necrotrophic pathogens that feed on necrotic tissue; on the contrary, this response plays a beneficial role in defense against biotrophic pathogens that depend on living tissue for successful host colonization. Thus, apoplastic PAs play important roles in plant-pathogen interactions, and modulation of host PA levels, particularly in the leaf apoplast, may lead to significant changes in host susceptibility to different kinds of pathogens.

  7. Apoplastic Polyamine Oxidation Plays Different Roles in Local Responses of Tobacco to Infection by the Necrotrophic Fungus Sclerotinia sclerotiorum and the Biotrophic Bacterium Pseudomonas viridiflava1[W

    Science.gov (United States)

    Marina, María; Maiale, Santiago Javier; Rossi, Franco Rubén; Romero, Matías Fernando; Rivas, Elisa Isabel; Gárriz, Andrés; Ruiz, Oscar Adolfo; Pieckenstain, Fernando Luis

    2008-01-01

    The role of polyamine (PA) metabolism in tobacco (Nicotiana tabacum) defense against pathogens with contrasting pathogenic strategies was evaluated. Infection by the necrotrophic fungus Sclerotinia sclerotiorum resulted in increased arginine decarboxylase expression and activity in host tissues, as well as putrescine and spermine accumulation in leaf apoplast. Enhancement of leaf PA levels, either by using transgenic plants or infiltration with exogenous PAs, led to increased necrosis due to infection by S. sclerotiorum. Specific inhibition of diamine and PA oxidases attenuated the PA-induced enhancement of leaf necrosis during fungal infection. When tobacco responses to infection by the biotrophic bacterium Pseudomonas viridiflava were investigated, an increase of apoplastic spermine levels was detected. Enhancement of host PA levels by the above-described experimental approaches strongly decreased in planta bacterial growth, an effect that was blocked by a PA oxidase inhibitor. It can be concluded that accumulation and further oxidation of free PAs in the leaf apoplast of tobacco plants occurs in a similar, although not identical way during tobacco defense against infection by microorganisms with contrasting pathogenesis strategies. This response affects the pathogen's ability to colonize host tissues and results are detrimental for plant defense against necrotrophic pathogens that feed on necrotic tissue; on the contrary, this response plays a beneficial role in defense against biotrophic pathogens that depend on living tissue for successful host colonization. Thus, apoplastic PAs play important roles in plant-pathogen interactions, and modulation of host PA levels, particularly in the leaf apoplast, may lead to significant changes in host susceptibility to different kinds of pathogens. PMID:18583531

  8. Experimental results for oscillatory water flow in 10-ppi metal foam at low-frequencies

    Science.gov (United States)

    Bağcı, Ö.; Arbak, A.; De Paepe, M.; Dukhan, N.

    2016-09-01

    This experimental study presents results and interpretation of oscillatory water flow in open-cell metal foam. The tested foam had 10 pores per inch and a por