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Sample records for additional surface water

  1. Atmospheric transport and deposition, an additional input pathway for triazine herbicides to surface waters

    SciTech Connect

    Muir, D.C.G.; Rawn, D.F.

    1996-10-01

    Although surface runoff from treated fields is regarded as the major route of entry of triazine herbicides to surface waters, other pathways such as deposition via precipitation, gas absorption and dryfall may also be important. Triazine herbicides have been detected in precipitation but there has been only a very limited amount of work on gas phase and aerosols. To examine the importance of atmospheric inputs concentrations of atrazine, cyanazine and terbuthylazine in gas phase/aerosols, precipitation, and surface waters were determined (along with other herbicides) using selected ion GC-MS. Atrazine was detected at low ng/L concentrations in surface waters (<0.04-5.3 ng/L) and precipitation (0.1-53 ng/L), and at 0.02-0.1 ng/m{sup 3} in air. Cyanazine and terbuthylazine were detected in air and infrequently in water. Highest atrazine concentrations in air were found during June each year on both gas phase and particles. Concentrations of atrazine in surface waters at both locations increased during June, even in the absence of precipitation or overland flow, presumably due to inputs from dryfall and to gas areas and boreal forest lakes due to transport and deposition. Ecological risk assessment of triazines, especially for pristine aquatic environments should include consideration of this atmospheric pathway.

  2. Water-Insoluble Surface Coatings of Polyion-Surfactant Ion Complex Salts Respond to Additives in a Surrounding Aqueous Solution.

    PubMed

    Gustavsson, Charlotte; Obiols-Rabasa, Marc; Piculell, Lennart

    2015-06-16

    Hydrated, but water-insoluble, "complex salts" (CS) composed of alkyltrimethylammonium surfactant ions with polyacrylate counterions are known to exhibit a rich phase behavior in bulk mixtures with water and have recently been shown to act as water-responsive surface coatings. Here it is shown, by SAXS measurements, that surface coatings of CS also respond to various added solutes in a surrounding aqueous solution, by altering their liquid crystalline structure. The obtained results provide new information on the phase behavior of CS in contact with water and aqueous solutions. Solutes such as acids, salts, excess ionic surfactant, or water-soluble polymers act on the CS by altering the polyion charge density, screening the electrostatic interaction, changing the curvature of the surfactant aggregate, or increasing the osmotic pressuring in the surrounding solution, all of which may result in a phase transition in the film. In water, all studied CS surface coatings had a micellar cubic structure, which could change to 2D hexagonal, HCP, or disordered micellar structure, depending on the identity of the CS and the identity and concentration of the added solute. For some systems, even dissolved CO2 from the ambient air was sufficient to induce a structural change in the film. Especially the films containing the long polyions remained intact even for large concentrations of solutes in the contacting solutions, and extensive washing in water resulted, in most cases, in films with the "original" structure found in water. PMID:26017683

  3. Enantioselective Michael Addition of Water

    PubMed Central

    Chen, Bi-Shuang; Resch, Verena; Otten, Linda G; Hanefeld, Ulf

    2015-01-01

    The enantioselective Michael addition using water as both nucleophile and solvent has to date proved beyond the ability of synthetic chemists. Herein, the direct, enantioselective Michael addition of water in water to prepare important β-hydroxy carbonyl compounds using whole cells of Rhodococcus strains is described. Good yields and excellent enantioselectivities were achieved with this method. Deuterium labeling studies demonstrate that a Michael hydratase catalyzes the water addition exclusively with anti-stereochemistry. PMID:25529526

  4. Enantioselective Michael addition of water.

    PubMed

    Chen, Bi-Shuang; Resch, Verena; Otten, Linda G; Hanefeld, Ulf

    2015-02-01

    The enantioselective Michael addition using water as both nucleophile and solvent has to date proved beyond the ability of synthetic chemists. Herein, the direct, enantioselective Michael addition of water in water to prepare important β-hydroxy carbonyl compounds using whole cells of Rhodococcus strains is described. Good yields and excellent enantioselectivities were achieved with this method. Deuterium labeling studies demonstrate that a Michael hydratase catalyzes the water addition exclusively with anti-stereochemistry.

  5. Addition of surfactants in ozonated water cleaning for the suppression of functional group formation and particle adhesion on the SiO2 surface

    NASA Astrophysics Data System (ADS)

    Yang, Jahyun; Im, Kyungtaek; Lim, Sangwoo

    2011-04-01

    Various kinds of surfactants were added to a cleaning solution and deionized (DI) water, and their effect on the suppression of organic function group formation and particle adhesion to a SiO2 surface was analyzed using multi-internal reflection Fourier transform infrared spectroscopy. The results implied that attached organic functional groups are affected by the chemical structure of a surfactant in DI water. Furthermore, the addition of anionic glycolic acid ethoxylate 4-tert-butylphenyl ether (GAE4E) is the most effective in terms of preventing organic group attachment and particle adhesion to the SiO2 surface, whether it was added to the cleaning solution or post-cleaning rinse water, with or without polystyrene latex particles. Moreover, it was possible to completely prevent particle adhesion to the SiO2 surface with the proper addition of GAE4E in DIO3 solution.

  6. Surface freezing of water.

    PubMed

    Pérez-Díaz, J L; Álvarez-Valenzuela, M A; Rodríguez-Celis, F

    2016-01-01

    Freezing, melting, evaporation and condensation of water are essential ingredients for climate and eventually life on Earth. In the present work, we show how surface freezing of supercooled water in an open container is conditioned and triggered-exclusively-by humidity in air. Additionally, a change of phase is demonstrated to be triggered on the water surface forming surface ice crystals prior to freezing of bulk. The symmetry of the surface crystal, as well as the freezing point, depend on humidity, presenting at least three different types of surface crystals. Humidity triggers surface freezing as soon as it overpasses a defined value for a given temperature, generating a plurality of nucleation nodes. An evidence of simultaneous nucleation of surface ice crystals is also provided. PMID:27330895

  7. Surface freezing of water.

    PubMed

    Pérez-Díaz, J L; Álvarez-Valenzuela, M A; Rodríguez-Celis, F

    2016-01-01

    Freezing, melting, evaporation and condensation of water are essential ingredients for climate and eventually life on Earth. In the present work, we show how surface freezing of supercooled water in an open container is conditioned and triggered-exclusively-by humidity in air. Additionally, a change of phase is demonstrated to be triggered on the water surface forming surface ice crystals prior to freezing of bulk. The symmetry of the surface crystal, as well as the freezing point, depend on humidity, presenting at least three different types of surface crystals. Humidity triggers surface freezing as soon as it overpasses a defined value for a given temperature, generating a plurality of nucleation nodes. An evidence of simultaneous nucleation of surface ice crystals is also provided.

  8. Literature review and need for additional study of surface-water quality in the Cuyahoga Valley National Recreation Area, Ohio

    USGS Publications Warehouse

    Childress, C.J.

    1984-01-01

    The Cuyahoga Valley National Recreation Area encompasses about 24 miles of the middle reach of the Cuyahoga River and parts of four major tributaries -- Furnace Run, Brandywine Creek, Chippewa Creek, and TInkers Creek. Water quality in this reach does not meet Ohio water-quality standards for dissolved oxygen, fecal bacteria, ammonia, and lead. Point sources of effluent contribute contaminants. On the basis of a review of scientific and technical literature, National Park Service management goals, and water-quality data collected by the U.S. Geological Survey, three subject areas for future study are suggested: (1) The dissolved oxygen regime, (2) chemical quality of base flow, and (3) quality of storm-water runoff.

  9. Surface tension increment due to solute addition

    NASA Astrophysics Data System (ADS)

    Hsin, Wei Lun; Sheng, Yu-Jane; Lin, Shi-Yow; Tsao, Heng-Kwong

    2004-03-01

    Addition of solute into solvent may lead to an increase in surface tension, such as salt in water and water in alcohol, due to solute depletion at the interface. The repulsion of the solute from the interface may originate from electrostatic forces or solute-solvent attraction. On the basis of the square-well model for the interface-solute interaction, we derive the surface tension increment Δγ by both canonical and grand-canonical routes (Gibbs adsorption isotherm) for a spherical droplet. The surface tension is increased linearly with the bulk concentration of the solute cb and the interaction range λ. The theoretical results are consistent with those obtained by experiments and Monte Carlo simulations up to a few molarity. For weak repulsion, the increment is internal energy driven. When the repulsion is large enough, the surface tension increment is entropy driven and approaches the asymptotic limit, Δγ≃cbkBTλ, due to the nearly complete depletion of the solute at the interface. Our result may shed some light on the surface tension increment for electrolyte solutions with concentration above 0.2M.

  10. Influence of type and level of water-soluble additives on drug release and surface and mechanical properties of Surelease films.

    PubMed

    Rohera, Bhagwan D; Parikh, Nilesh H

    2002-11-01

    Ethylcellulose in combination with water-soluble additives has been used in the development of microporous membrane-coated dosage forms. In the present study, application of three types of water-soluble additives, namely polyethylene glycols (PEG 400, 3350, and 8000), maltodextrins (Maltrin M150, M100, and M040 in the order of lower to higher average polymer size and molecular weight; dextrose equivalence 16.9, 11.1, and 4.8, respectively), and xylitol, as porosity modifiers in the films of a commercially available aqueous ethylcellulose dispersion (Surelease/E-7-7060 plasticized with glyceryl tricaprylate/caprate) was investigated. The effect of type and level of these additives on drug release characteristics and surface and mechanical properties of the polymeric films was studied. Each additive was incorporated at 20 and 30% levels in the polymeric dispersion based on its solids content. Ibuprofen tablets were coated using the polymeric dispersion with and without additive at 3% w/w coat level in a fluid-bed equipment. The coated tablets were evaluated for their drug release rate, coat reflectivity (gloss), Brinell hardness, and elastic modulus. Differential scanning calorimetric analysis of the films was performed to determine the physico-chemical changes in the applied film-coats. The rate of drug release, hence film porosity, was observed to be dependent on the type and level of the additive added. The molecular weight of the additive and its concentration in the polymeric dispersion had significant influence on the rate of drug release, hardness, and elasticity of the film-coats.

  11. Sustaining dry surfaces under water

    PubMed Central

    Jones, Paul R.; Hao, Xiuqing; Cruz-Chu, Eduardo R.; Rykaczewski, Konrad; Nandy, Krishanu; Schutzius, Thomas M.; Varanasi, Kripa K.; Megaridis, Constantine M.; Walther, Jens H.; Koumoutsakos, Petros; Espinosa, Horacio D.; Patankar, Neelesh A.

    2015-01-01

    Rough surfaces immersed under water remain practically dry if the liquid-solid contact is on roughness peaks, while the roughness valleys are filled with gas. Mechanisms that prevent water from invading the valleys are well studied. However, to remain practically dry under water, additional mechanisms need consideration. This is because trapped gas (e.g. air) in the roughness valleys can dissolve into the water pool, leading to invasion. Additionally, water vapor can also occupy the roughness valleys of immersed surfaces. If water vapor condenses, that too leads to invasion. These effects have not been investigated, and are critically important to maintain surfaces dry under water. In this work, we identify the critical roughness scale, below which it is possible to sustain the vapor phase of water and/or trapped gases in roughness valleys – thus keeping the immersed surface dry. Theoretical predictions are consistent with molecular dynamics simulations and experiments. PMID:26282732

  12. Surface texture measurement for additive manufacturing

    NASA Astrophysics Data System (ADS)

    Triantaphyllou, Andrew; Giusca, Claudiu L.; Macaulay, Gavin D.; Roerig, Felix; Hoebel, Matthias; Leach, Richard K.; Tomita, Ben; Milne, Katherine A.

    2015-06-01

    The surface texture of additively manufactured metallic surfaces made by powder bed methods is affected by a number of factors, including the powder’s particle size distribution, the effect of the heat source, the thickness of the printed layers, the angle of the surface relative to the horizontal build bed and the effect of any post processing/finishing. The aim of the research reported here is to understand the way these surfaces should be measured in order to characterise them. In published research to date, the surface texture is generally reported as an Ra value, measured across the lay. The appropriateness of this method for such surfaces is investigated here. A preliminary investigation was carried out on two additive manufacturing processes—selective laser melting (SLM) and electron beam melting (EBM)—focusing on the effect of build angle and post processing. The surfaces were measured using both tactile and optical methods and a range of profile and areal parameters were reported. Test coupons were manufactured at four angles relative to the horizontal plane of the powder bed using both SLM and EBM. The effect of lay—caused by the layered nature of the manufacturing process—was investigated, as was the required sample area for optical measurements. The surfaces were also measured before and after grit blasting.

  13. Surface-water surveillance

    SciTech Connect

    Saldi, K.A.; Dirkes, R.L.; Blanton, M.L.

    1995-06-01

    This section of the 1994 Hanford Site Environmental Report summarizes the Surface water on and near the Hanford Site is monitored to determine the potential effects of Hanford operations. Surface water at Hanford includes the Columbia River, riverbank springs, ponds located on the Hanford Site, and offsite water systems directly east and across the Columbia River from the Hanford Site, and offsite water systems directly east and across the Columbia River from the Hanford Site. Columbia River sediments are also included in this discussion. Tables 5.3.1 and 5.3.2 summarize the sampling locations, sample types, sampling frequencies, and sample analyses included in surface-water surveillance activities during 1994. Sample locations are also identified in Figure 5.3.1. This section describes the surveillance effort and summarizes the results for these aquatic environments. Detailed analytical results are reported by Bisping (1995).

  14. The Fate of Carbon Draining Permafrost Soils is Controlled by Photochemical Reactions in Addition to Microbial Degradation in Arctic Surface Waters

    NASA Astrophysics Data System (ADS)

    Kling, G. W.; Dobkowski, J.; Ward, C. P.; Crump, B. C.; Neilson, B. T.; Cory, R. M.

    2013-12-01

    Perhaps the unknown of greatest potential consequence in determining the arc of climate change in this century is the role of thawing permafrost carbon. Arctic soil temperatures are increasing and large areas of permafrost have thawed, but not all soils will thaw quietly in place. Destabilization from melting ice has caused an increase in thermokarst failures that expose buried C and release dissolved organic C (DOC) to surface waters. We found that this exposure to sunlight and surface conditions increases the reactivity of permafrost C to microbial attack by 40% compared to soil DOC held in the dark. The range of lability to microbes depends on microbial community composition and especially on prior light exposure, implying that sunlight may act as an amplification factor in converting frozen C to gases in the atmosphere. We also found that photochemical degradation accounted for the majority (up to 80%) of the degradation of DOC in the water column of lakes and streams. This was based on concurrent measurements of (1) respiration of DOM to CO2 by bacteria in the dark, (2) O2 consumed in DOM photo-oxidation, (3) CO2 produced by DOM photo-mineralization, and (4) photo-stimulated bacterial respiration. Using in-situ UV light profiles and surveys of ~70 surface waters on the North Slope of Alaska, we found that depth-integrated water column rates of photochemical DOM degradation equaled or exceeded dark bacterial respiration, by up to 7x depending on the mean depth of the water column. The total dark and light processing of DOM in these waters was estimated to be roughly 20% of the DOM exported from major rivers on the North Slope of Alaska to the Arctic Ocean. The dominant degradation pathway was the partial photo-oxidation of DOC, which was at least 2x greater than complete photo-mineralization of DOC to CO2 or than bacterial respiration to CO2. This means that the dominant fate of permafrost C released as DOC is to be partially degraded and transported through

  15. Surface Water in Hawaii

    USGS Publications Warehouse

    Oki, Delwyn S.

    2003-01-01

    Surface water in Hawaii is a valued resource as well as a potential threat to human lives and property. The surface-water resources of Hawaii are of significant economic, ecologic, cultural, and aesthetic importance. Streams supply more than 50 percent of the irrigation water in Hawaii, and although streams supply only a few percent of the drinking water statewide, surface water is the main source of drinking water in some places. Streams also are a source of hydroelectric power, provide important riparian and instream habitats for many unique native species, support traditional and customary Hawaiian gathering rights and the practice of taro cultivation, and possess valued aesthetic qualities. Streams affect the physical, chemical, and aesthetic quality of receiving waters, such as estuaries, bays, and nearshore waters, which are critical to the tourism-based economy of the islands. Streams in Hawaii pose a danger because of their flashy nature; a stream's stage, or water level, can rise several feet in less than an hour during periods of intense rainfall. Streams in Hawaii are flashy because rainfall is intense, drainage basins are small, basins and streams are steep, and channel storage is limited. Streamflow generated during periods of heavy rainfall has led to loss of property and human lives in Hawaii. Most Hawaiian streams originate in the mountainous interiors of the islands and terminate at the coast. Streams are significant sculptors of the Hawaiian landscape because of the erosive power of the water they convey. In geologically young areas, such as much of the southern part of the island of Hawaii, well-defined stream channels have not developed because the permeability of the surface rocks generally is so high that rainfall infiltrates before flowing for significant distances on the surface. In geologically older areas that have received significant rainfall, streams and mass wasting have carved out large valleys.

  16. Cryptosporidiosis and surface water.

    PubMed Central

    Gallaher, M M; Herndon, J L; Nims, L J; Sterling, C R; Grabowski, D J; Hull, H F

    1989-01-01

    In the period July through October, 1986, 78 laboratory-confirmed cases of cryptosporidiosis were identified in New Mexico. To determine possible risk factors for development of this disease, we conducted a case-control study; 24 case-patients and 46 neighborhood controls were interviewed. Seventeen (71 per cent) of the 24 case-patients were females, seven (29%) were males; their ages ranged from 4 months to 44 years, median 3 years. There was a strong association between drinking surface water and illness: five of the 24 case-patients, but none of the 46 controls drank untreated surface water. Among children, illness was also associated with attending a day care center where other children were ill (odds ratio = 13.1). PMID:2909180

  17. Fire extinct experiments with water mist by adding additives

    NASA Astrophysics Data System (ADS)

    Yang, Lijun; Zhao, Jianbo

    2011-12-01

    The effects of fire extinguishment with water mist by adding different additives were studied. Tens of chemical substances (including alkali metal salt, dilution agent and surface active agent) were selected as additives due to their different extinct mechanisms. At first the performance of fire extinguishment with single additive was studied, then the effects of the same kinds of chemical substances under the same mass fraction were compared to study their influences on the fire extinguishment factors, including extinct time, fire temperature and oxygen concentration from which the fire extinct mechanism with additives could be concluded. Based on this the experiments were conducted to study the cooperate effect of the complexity of different additives. It indicated the relations between different firefighting mechanisms and different additives were competitive. From a large number of experiments the extinct mechanism with water mist by adding additives was concluded and an optimal compounding additive was selected.

  18. Internal Surface Water Flows

    USGS Publications Warehouse

    Murray, Mitchell H.

    1999-01-01

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

  19. Water addition, evaporation and water holding capacity of poultry litter.

    PubMed

    Dunlop, Mark W; Blackall, Patrick J; Stuetz, Richard M

    2015-12-15

    Litter moisture content has been related to ammonia, dust and odour emissions as well as bird health and welfare. Improved understanding of the water holding properties of poultry litter as well as water additions to litter and evaporation from litter will contribute to improved litter moisture management during the meat chicken grow-out. The purpose of this paper is to demonstrate how management and environmental conditions over the course of a grow-out affect the volume of water A) applied to litter, B) able to be stored in litter, and C) evaporated from litter on a daily basis. The same unit of measurement has been used to enable direct comparison-litres of water per square metre of poultry shed floor area, L/m(2), assuming a litter depth of 5cm. An equation was developed to estimate the amount of water added to litter from bird excretion and drinking spillage, which are sources of regular water application to the litter. Using this equation showed that water applied to litter from these sources changes over the course of a grow-out, and can be as much as 3.2L/m(2)/day. Over a 56day grow-out, the total quantity of water added to the litter was estimated to be 104L/m(2). Litter porosity, water holding capacity and water evaporation rates from litter were measured experimentally. Litter porosity decreased and water holding capacity increased over the course of a grow-out due to manure addition. Water evaporation rates at 25°C and 50% relative humidity ranged from 0.5 to 10L/m(2)/day. Evaporation rates increased with litter moisture content and air speed. Maintaining dry litter at the peak of a grow-out is likely to be challenging because evaporation rates from dry litter may be insufficient to remove the quantity of water added to the litter on a daily basis.

  20. Water on a Hydrophobic surface

    NASA Astrophysics Data System (ADS)

    Scruggs, Ryan; Zhu, Mengjue; Poynor, Adele

    2012-02-01

    Hydrophobicity, meaning literally fear of water, is exhibited on the surfaces of non-stick cooking pans and water resistant clothing, on the leaves of the lotus plan, or even during the protein folding process in our bodies. Hydrophobicity is directly measured by determining a contact angle between water and an objects surface. Associated with a hydrophobic surface is the depletion layer, a low density region approximately 0.2 nm thick. We study this region by comparing data found in lab using surface plasmon resonance techniques to theoretical calculations. Experiments use gold slides coated in ODT and Mercapto solutions to model both hydrophobic and hydrophilic surfaces respectively.

  1. Identifying vulnerable surface water utilities

    SciTech Connect

    Clark, R.M.; Grayman, W.M.; Males, R.M.; Kilgore, R.

    1989-01-01

    Although industrial discharges from point sources are regulated by the Federal Water Pollution Control Acts, National Pollutant Discharge Elimination System (NPDES), some toxic pollutants continue to be discharged into surface waters. Frequently these same surface waters are major sources of drinking water. The Safe Drinking Water Act Amendments have specified a large number of new contaminant levels, (MCLs) at the microgram per liter level. It is possible that many water utilities finding that these new MCLs are violated will seek to identify upstream dischargers and request that regulatory agencies force them to install discharge controls rather than pay for expensive water treatment processes. The study reported in the paper documents the development of a data base management system and a water quality modeling approach that allows drinking water utilities to assess the impact of these upstream discharges on raw water quality. The report makes recommendations to USEPA for modifying its NPDES procedures.

  2. THE FATE OF FLUOROSILICATE DRINKING WATER ADDITIVES

    EPA Science Inventory

    Periodically, the EPA reexamines its information on regulated drinking water contaminants to deterime if further study is required. Fluoride is one such contaminant undergoing review. The chemical literature indicates that some deficiencies exist in our understanding of the spe...

  3. Surface Water Response Modeling

    EPA Science Inventory

    During response to spills, or for facility planning, the vulnerability of downstream water resources is a major concern. How long and at what concentration do spilled contaminants reach downstream receptors? Models have the potential to answer these questions, but only if they ...

  4. Measuring Surface Water From Space

    NASA Astrophysics Data System (ADS)

    Partsch, J.; Alsdorf, D.; Rodriguez, E.; Lettenmaier, D.; Mognard, N.; Participants, T.

    2006-12-01

    Surface fresh water is essential for life, yet we have surprisingly poor knowledge of the spatial and temporal dynamics of surface fresh water discharge and changes in storage globally. For example, we are unable to answer such basic questions as "What is the spatial and temporal variability of water stored on and near the surface of all continents?" Furthermore, key societal issues, such as the susceptibility of life to flood hazards, cannot be answered with the current global, in-situ networks designed to observe river discharge at points but not flood events. The measurements required to answer these hydrologic questions are surface water area, the elevation of the water surface (h), its slope (dh/dx), and temporal change (dh/dt). Advances in remote sensing hydrology, particularly over the past 10 years and even more recently, have demonstrated that these hydraulic variables can be measured reliably from orbiting platforms. Measurements of inundated area have been used to varying degrees of accuracy as proxies for discharge, but are successful only when in-situ data are available for calibration and fail to indicate the dynamic topography of water surfaces. Radar altimeters have a rich, multi-decadal history of successfully measuring elevations of the ocean surface and are now also accepted as capable tools for measuring h along orbital profiles crossing fresh water bodies. However, altimeters are profiling tools which, because of their orbital spacings, miss too many fresh water bodies to be useful hydrologically. High spatial resolution images of dh/dt have been observed with interferometric synthetic aperture radar (SAR), but the method requires emergent vegetation to scatter radar pulses back to the receiving antenna. Essentially, existing spaceborne methods have been used to measure components of surface water hydraulics, but none of the technologies can singularly supply the water volume and hydraulic measurements that are needed to accurately model the

  5. Measuring surface water from space

    NASA Astrophysics Data System (ADS)

    Alsdorf, Douglas E.; RodríGuez, Ernesto; Lettenmaier, Dennis P.

    2007-06-01

    Surface fresh water is essential for life, yet we have surprisingly poor knowledge of the spatial and temporal dynamics of surface freshwater discharge and changes in storage globally. For example, we are unable to answer such basic questions as "What is the spatial and temporal variability of water stored on and near the surface of all continents?" Furthermore, key societal issues, such as the susceptibility of life to flood hazards, cannot be answered with the current global, in situ networks designed to observe river discharge at points but not flood events. The measurements required to answer these hydrologic questions are surface water area, the elevation of the water surface (h), its slope (∂h/∂x), and temporal change (∂h/∂t). Advances in remote sensing hydrology, particularly over the past 10 years and even more recently, have demonstrated that these hydraulic variables can be measured reliably from orbiting platforms. Measurements of inundated area have been used to varying degrees of accuracy as proxies for discharge but are successful only when in situ data are available for calibration; they fail to indicate the dynamic topography of water surfaces. Radar altimeters have a rich, multidecadal history of successfully measuring elevations of the ocean surface and are now also accepted as capable tools for measuring h along orbital profiles crossing freshwater bodies. However, altimeters are profiling tools, which, because of their orbital spacings, miss too many freshwater bodies to be useful hydrologically. High spatial resolution images of ∂h/∂t have been observed with interferometric synthetic aperture radar, but the method requires emergent vegetation to scatter radar pulses back to the receiving antenna. Essentially, existing spaceborne methods have been used to measure components of surface water hydraulics, but none of the technologies can singularly supply the water volume and hydraulic measurements that are needed to accurately model

  6. Possibilities of obtaining an additional water supply near Hingham, Massachusetts

    USGS Publications Warehouse

    Brashears, M.L.

    1942-01-01

    In February 1942 the War Production Board requested the U.S. Geological Survey to furnish information on the possibilities of obtaining additional water supply near the shore at Hingham, Mass. It was estimated that 300,000 to 500,000 gallons a day was needed. On February 25 and 26, 1942, a brief field study of the ground-water conditions was made in an area about 2 miles wide along the shore of Hingham Bay at Hingham, Mass. Most of this area is shown on the topographic map of the Weymouth Quadrangle, Mass., surveyed by the U.S. Geological Survey in 1936. The field work of the ground-water study consisted mainly of surface transverses and the examination of road cuts and gravel pits. In addition, well records and other data were collected from well drillers and public officials. Acknowledgement is made to H. B. Kinnison, district engineer, U.S. Geological Survey, at Boston, Mass., for his assistance and suggestions.

  7. 10. Water treatment plant, view to S. 1965 addition is ...

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

    10. Water treatment plant, view to S. 1965 addition is in the foreground - Fort Benton Water Treatment Plant, Filtration Plant, Lots 9-13 of Block 7, Fort Benton Original Townsite at Missouri River, Fort Benton, Chouteau County, MT

  8. Persisting water droplets on water surfaces.

    PubMed

    Klyuzhin, Ivan S; Ienna, Federico; Roeder, Brandon; Wexler, Adam; Pollack, Gerald H

    2010-11-11

    Droplets of various liquids may float on the respective surfaces for extended periods of time prior to coalescence. We explored the features of delayed coalescence in highly purified water. Droplets several millimeters in diameter were released from a nozzle onto a water surface. Results showed that droplets had float times up to hundreds of milliseconds. When the droplets did coalesce, they did so in stepwise fashion, with periods of quiescence interspersed between periods of coalescence. Up to six steps were noted before the droplet finally vanished. Droplets were released in a series, which allowed the detection of unexpected abrupt float-time changes throughout the duration of the series. Factors such as electrostatic charge, droplet size, and sideways motion had considerable effect on droplet lifetime, as did reduction of pressure, which also diminished the number of steps needed for coalescence. On the basis of present observations and recent reports, a possible mechanism for noncoalescence is considered. PMID:20961076

  9. 21 CFR 173.310 - Boiler water additives.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... Boiler water additives. Boiler water additives may be safely used in the preparation of steam that will.... The mixture is used as an anticorrosive agent in steam boiler distribution systems, with each... nitrilotriacetate Not to exceed 5 parts per million in boiler feedwater; not to be used where steam will be...

  10. Polarimetric thermal emission from periodic water surfaces

    NASA Technical Reports Server (NTRS)

    Yueh, S. H.; Nghiem, S. V.; Kwok, R.; Wilson, W. J.; Li, F. K.; Johnson, J. T.; Kong, J. A.

    1993-01-01

    Experimental results and theoretical calculations are presented to study the polarimetric emission from water surfaces with directional features. For our ground-based Ku-band radiometer measurements, a water pool was constructed on the roof of a building in the Jet Propulsion Laboratory, and a fiberglass surface with periodic corrugations in one direction was impressed on the top of the water surface to create a stationary water surface underneath it. It is observed that the measured Stokes parameters of corrugated fiberglass-covered water surfaces are functions of azimuth angles and agree very well with the theoretical calculations. The theory, after being verified by the experimental data, was then used to calculate the Stokes parameters of periodic surfaces without fiberglass surface layer and with rms height of the order of wind-generated water ripples. The magnitudes of the azimuthal variation of the calculated emissivities at horizontal and vertical polarizations corresponding to the first two Stokes parameters are found to be comparable to the values measured by airborne radiometers and SSM/I. In addition, the third Stokes parameter not shown in the literature is seen to have approximately twice the magnitude of the azimuth variation of either T(sub h) or T(sub v), which may make it more sensitive to the row direction, while less susceptive to noises because the atmospheric and system noises tend to be unpolarized and are expected to be cancelled out when the third Stokes parameter is derived as the difference of two or three power measurements, as indicated by another experiment carried out at a swimming pool with complicated surroundings. The results indicate that passive polarimetry is a potential technology in the remote sensing of ocean wind vector which is a crucial component in the understanding of global climate change. Issues related to the application of microwave passive polarimetry to ocean wind are also discussed.

  11. Water-soluble fluorochemical surfactant well stimulation additives

    SciTech Connect

    Clark, H.B.; Pike, M.T.; Rengel, G.L.

    1982-07-01

    Water-soluble fluorochemical surfactants have been used in the oilfield since the early 1970's as surface tension depressants in a variety of aqueous stimulation fluids for low-permeability oil and gas wells. A discussion is presented of a laboratory study of the behavior of water-soluble fluorochemical surfactants relative to their oilfield use. Data are presented on surface tension depression, thermal stability, adsorption, fluid removal from sandpacks, flow rates, and emulsification tendencies. 7 refs.

  12. Bubble formation in water with addition of a hydrophobic solute.

    PubMed

    Okamoto, Ryuichi; Onuki, Akira

    2015-07-01

    We show that phase separation can occur in a one-component liquid outside its coexistence curve (CX) with addition of a small amount of a solute. The solute concentration at the transition decreases with increasing the difference of the solvation chemical potential between liquid and gas. As a typical bubble-forming solute, we consider O2 in ambient liquid water, which exhibits mild hydrophobicity and its critical temperature is lower than that of water. Such a solute can be expelled from the liquid to form gaseous domains while the surrounding liquid pressure is higher than the saturated vapor pressure p cx. This solute-induced bubble formation is a first-order transition in bulk and on a partially dried wall, while a gas film grows continuously on a completely dried wall. We set up a bubble free energy ΔG for bulk and surface bubbles with a small volume fraction ϕ. It becomes a function of the bubble radius R under the Laplace pressure balance. Then, for sufficiently large solute densities above a threshold, ΔG exhibits a local maximum at a critical radius and a minimum at an equilibrium radius. We also examine solute-induced nucleation taking place outside CX, where bubbles larger than the critical radius grow until attainment of equilibrium. PMID:26142694

  13. Surface-Water Conditions in Georgia, Water Year 2005

    USGS Publications Warehouse

    Painter, Jaime A.; Landers, Mark N.

    2007-01-01

    INTRODUCTION The U.S. Geological Survey (USGS) Georgia Water Science Center-in cooperation with Federal, State, and local agencies-collected surface-water streamflow, water-quality, and ecological data during the 2005 Water Year (October 1, 2004-September 30, 2005). These data were compiled into layers of an interactive ArcReaderTM published map document (pmf). ArcReaderTM is a product of Environmental Systems Research Institute, Inc (ESRI?). Datasets represented on the interactive map are * continuous daily mean streamflow * continuous daily mean water levels * continuous daily total precipitation * continuous daily water quality (water temperature, specific conductance dissolved oxygen, pH, and turbidity) * noncontinuous peak streamflow * miscellaneous streamflow measurements * lake or reservoir elevation * periodic surface-water quality * periodic ecological data * historical continuous daily mean streamflow discontinued prior to the 2005 water year The map interface provides the ability to identify a station in spatial reference to the political boundaries of the State of Georgia and other features-such as major streams, major roads, and other collection stations. Each station is hyperlinked to a station summary showing seasonal and annual stream characteristics for the current year and for the period of record. For continuous discharge stations, the station summary includes a one page graphical summary page containing five graphs, a station map, and a photograph of the station. The graphs provide a quick overview of the current and period-of-record hydrologic conditions of the station by providing a daily mean discharge graph for the water year, monthly statistics graph for the water year and period of record, an annual mean streamflow graph for the period of record, an annual minimum 7-day average streamflow graph for the period of record, and an annual peak streamflow graph for the period of record. Additionally, data can be accessed through the layer's link

  14. Sulfate deposition to surface waters

    SciTech Connect

    Henriksen, A.; Brakke, D.F.

    1988-01-01

    Critical loads are the highest deposition of strong acid anions in surface waters that will not cause harmful biological effects on populations, such as declines in or extinctions of fish. Our analysis focuses on sulfate deposition because in glaciated regions sulfate is conservative in soils, whereas nitrate in biologically cycled. Sulfate also is the dominant anion in acidic deposition and in most acidic lakes. This analysis, represents the first evaluation of certain data available from Norway and the eastern United States, with an emphasis on the data from Scandinavia. The concept of dose-response is widely used in connection with water pollution. Any lake system subjected to an external dose of pollutants will have an internal resistance (or buffer capacity) to the change. The response of the lake system will depend on the relative magnitudes of the dose and the resistance parameters.

  15. Surface modification of additive manufactured Ti6Al4V alloy with Ag nanoparticles: wettability and surface morphology study

    NASA Astrophysics Data System (ADS)

    Chudinova, E.; Surmeneva, M.; Koptioug, A.; Sharonova, A.; Loza, K.; Surmenev, R.

    2016-02-01

    In this work, the use of electrophoretic deposition to modify the surface of Ti6Al4V alloy fabricated via additive manufacturing technology is reported. Poly(vinylpyrrolidone) (PVP)-stabilized silver nanoparticles (AgNPs) had a spherical shape with a diameter of the metallic core of 100±20 nm and ζ -potential -15 mV. The AgNPs- coated Ti6Al4V alloy was studied in respect with its chemical composition and surface morphology, water contact angle, hysteresis, and surface free energy. The results of SEM microphotography analysis showed that the AgNPs were homogeneously distributed over the surface. Hysteresis and water contact angle measurements revealed the effect of the deposited AgNPs layer, namely an increased water contact angle and decreased contact angle hysteresis. However, the average water contact angle was 125° for PVP-stabilized-AgNPs-coated surface, whereas ethylene glycol gave the average contact angle of 17°. A higher surface energy is observed for AgNPs-coated Ti6Al4V surface (70.17 mN/m) compared with the uncoated surface (49.07 mN/m).

  16. 3D Additive Construction with Regolith for Surface Systems

    NASA Technical Reports Server (NTRS)

    Mueller, Robert P.

    2014-01-01

    Planetary surface exploration on Asteroids, the Moon, Mars and Martian Moons will require the stabilization of loose, fine, dusty regolith to avoid the effects of vertical lander rocket plume impingement, to keep abrasive and harmful dust from getting lofted and for dust free operations. In addition, the same regolith stabilization process can be used for 3 Dimensional ( 3D) printing, additive construction techniques by repeating the 2D stabilization in many vertical layers. This will allow in-situ construction with regolith so that materials will not have to be transported from Earth. Recent work in the NASA Kennedy Space Center (KSC) Surface Systems Office (NE-S) Swamp Works and at the University of Southern California (USC) under two NASA Innovative Advanced Concept (NIAC) awards have shown promising results with regolith (crushed basalt rock) materials for in-situ heat shields, bricks, landing/launch pads, berms, roads, and other structures that could be fabricated using regolith that is sintered or mixed with a polymer binder. The technical goals and objectives of this project are to prove the feasibility of 3D printing additive construction using planetary regolith simulants and to show that they have structural integrity and practical applications in space exploration.

  17. Water molecules orientation in surface layer

    NASA Astrophysics Data System (ADS)

    Klingo, V. V.

    2000-08-01

    The water molecules orientation has been investigated theoretically in the water surface layer. The surface molecule orientation is determined by the direction of a molecule dipole moment in relation to outward normal to the water surface. Entropy expressions of the superficial molecules in statistical meaning and from thermodynamical approach to a liquid surface tension have been found. The molecules share directed opposite to the outward normal that is hydrogen protons inside is equal 51.6%. 48.4% water molecules are directed along to surface outward normal that is by oxygen inside. A potential jump at the water surface layer amounts about 0.2 volts.

  18. Influence of mineral oil and additives on microhardness and surface chemistry of magnesium oxide (001) surface

    NASA Technical Reports Server (NTRS)

    Miyoshi, K.; Shigaki, H.; Buckley, D. H.

    1982-01-01

    X-ray photoelectron spectroscopy analyses and hardness experiments were conducted with cleaved magnesium oxide /001/ surfaces. The magnesium oxide bulk crystals were cleaved into specimens along the /001/ surface, and indentations were made on the cleaved surface in laboratory air, in nitrogen gas, or in degassed mineral oil with and without an additive while not exposing specimen surface to any other environment. The various additives examined contained sulfur, phosphorus, chlorine, or oleic acid. The sulfur-containing additive exhibited the highest hardness and smallest dislocation patterns evidencing plastic deformation; the chlorine-containing additive exhibited the lowest hardness and largest dislocation patterns evidencing plastic deformation. Hydrocarbon and chloride (MgCl2) films formed on the magnesium oxide surface. A chloride film was responsible for the lowest measured hardness.

  19. THE PERSISTENCE OF MYCOBACTERIUM AVIUM IN A DRINKING WATER SYSTEM AFTER THE ADDITION OF FILTRATION

    EPA Science Inventory

    Drinking water is increasingly recognized as a major source of pathogenic nontuberculous mycobacteria (NTM) associated with human infection. Our goal was to determine if the prevalence of NTM would decrease after the addition of filtration treatment to an unfiltered surface water...

  20. Persistence of Nontuberculous Mycobacteria in a Drinking Water System after Addition of Filtration Treatment

    PubMed Central

    Hilborn, Elizabeth D.; Covert, Terry C.; Yakrus, Mitchell A.; Harris, Stephanie I.; Donnelly, Sandra F.; Rice, Eugene W.; Toney, Sean; Bailey, Stephanie A.; Stelma, Gerard N.

    2006-01-01

    There is evidence that drinking water may be a source of infections with pathogenic nontuberculous mycobacteria (NTM) in humans. One method by which NTM are believed to enter drinking water distribution systems is by their intracellular colonization of protozoa. Our goal was to determine whether we could detect a reduction in the prevalence of NTM recovered from an unfiltered surface drinking water system after the addition of ozonation and filtration treatment and to characterize NTM isolates by using molecular methods. We sampled water from two initially unfiltered surface drinking water treatment plants over a 29-month period. One plant received the addition of filtration and ozonation after 6 months of sampling. Sample sites included those at treatment plant effluents, distributed water, and cold water taps (point-of-use [POU] sites) in public or commercial buildings located within each distribution system. NTM were recovered from 27% of the sites. POU sites yielded the majority of NTM, with >50% recovery despite the addition of ozonation and filtration. Closely related electrophoretic groups of Mycobacterium avium were found to persist at POU sites for up to 26 months. Water collected from POU cold water outlets was persistently colonized with NTM despite the addition of ozonation and filtration to a drinking water system. This suggests that cold water POU outlets need to be considered as a potential source of chronic human exposure to NTM. PMID:16957205

  1. Global modeling of fresh surface water temperature

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

    Temperature determines a range of water physical properties, the solubility of oxygen and other gases and acts as a strong control on fresh water biogeochemistry, influencing chemical reaction rates, phytoplankton and zooplankton composition and the presence or absence of pathogens. Thus, in freshwater ecosystems the thermal regime affects the geographical distribution of aquatic species through their growth and metabolism, tolerance to parasites, diseases and pollution and life history. Compared to statistical approaches, physically-based models of surface water temperature have the advantage that they are robust in light of changes in flow regime, river morphology, radiation balance and upstream hydrology. Such models are therefore better suited for projecting the effects of global change on water temperature. Till now, physically-based models have only been applied to well-defined fresh water bodies of limited size (e.g., lakes or stream segments), where the numerous parameters can be measured or otherwise established, whereas attempts to model water temperature over larger scales has thus far been limited to regression type of models. Here, we present a first attempt to apply a physically-based model of global fresh surface water temperature. The model adds a surface water energy balance to river discharge modelled by the global hydrological model PCR-GLOBWB. In addition to advection of energy from direct precipitation, runoff and lateral exchange along the drainage network, energy is exchanged between the water body and the atmosphere by short and long-wave radiation and sensible and latent heat fluxes. Also included are ice-formation and its effect on heat storage and river hydraulics. We used the coupled surface water and energy balance model to simulate global fresh surface water temperature at daily time steps on a 0.5x0.5 degree grid for the period 1970-2000. Meteorological forcing was obtained from the CRU data set, downscaled to daily values with ECMWF

  2. Mutagens in surface waters: a review.

    PubMed

    Ohe, Takeshi; Watanabe, Tetsushi; Wakabayashi, Keiji

    2004-11-01

    A review of the literature on the mutagenicity/genotoxicity of surface waters is presented in this article. Subheadings of this article include a description of sample concentration methods, mutagenic/genotoxic bioassay data, and suspected or identified mutagens in surface waters published in the literature since 1990. Much of the published surface water mutagenicity/genotoxicity studies employed the Salmonella/mutagenicity test with strains TA98 and/or TA100 with and/or without metabolic activation. Among all data analyzed, the percentage of positive samples toward TA98 was approximately 15%, both in the absence and the presence of S9 mix. Those positive toward TA100 were 7%, both with and without S9 mix. The percentage classified as highly mutagenic (2500-5000 revertants per liter) or extremely mutagenic (more than 5000 revertants per liter) was approximately 3-5% both towards TA98 and TA100, regardless of the absence or the presence of S9 mix. This analysis demonstrates that some rivers in the world, especially in Europe, Asia and South America, are contaminated with potent direct-acting and indirect-acting frameshift-type and base substitution-type mutagens. These rivers are reported to be contaminated by either partially treated or untreated discharges from chemical industries, petrochemical industries, oil refineries, oil spills, rolling steel mills, untreated domestic sludges and pesticides runoff. Aquatic organisms such as teleosts and bivalves have also been used as sentinels to monitor contamination of surface water with genotoxic chemicals. DNA modifications were analyzed for this purpose. Many studies indicate that the 32P-postlabeling assay, the single cell gel electrophoresis (comet) assay and the micronucleus test are sensitive enough to monitor genotoxic responses of indigenous aquatic organisms to environmental pollution. In order to efficiently assess the presence of mutagens in the water, in addition to the chemical analysis, mutagenicity

  3. Surface water discharges from onshore stripper wells.

    SciTech Connect

    Veil, J. A.

    1998-01-16

    Under current US Environmental Protection Agency (EPA) rules, small onshore oil producers are allowed to discharge produced water to surface waters with approval from state agencies; but small onshore gas producers, however, are prohibited from discharging produced water to surface waters. The purpose of this report is to identify those states that allow surface water discharges from small onshore oil operations and to summarize the types of permitting controls they use. It is intended that the findings of this report will serve as a rationale to encourage the EPA to revise its rules and to remove the prohibition on surface water discharges from small gas operations.

  4. Hematite Surface Activation by Chemical Addition of Tin Oxide Layer.

    PubMed

    Carvalho, Waldemir M; Souza, Flavio L

    2016-09-01

    In this study, the effect of tin (Sn(4+) ) modification on the surface of hematite electrodes synthesized by an aqueous solution route at different times (2, 5, 10, 18, and 24 h) is investigated. As confirmed from X-ray diffraction results, the as-synthesized electrode exhibits an oxyhydroxide phase, which is converted into a pure hematite phase after being subjected to additional thermal treatment at 750 °C for 30 min. The tin-modified hematite electrode is prepared by depositing a solution of Sn(4+) precursor on the as-synthesized electrode, followed by thermal treatment under the same abovementioned conditions. This modification results in an enhancement of the photocurrent response for all hematite electrodes investigated and attains the highest values of around 1.62 and 2.3 mA cm(-2) at 1.23 and 1.4 V versus RHE, respectively, for electrodes obtained in short synthesis times (2 h). Contact angle measurements suggest that the deposition of Sn(4+) on the hematite electrode provides a more hydrophilic surface, which favors a chemical reaction at the interface between the electrode and electrolyte. This result generates new perspectives for understanding the deposition of Sn(4+) on the hematite electrode surface, which is in contrast with several studies previously reported; these studies state that the enhancement in photocurrent density is related to either the induction of an increased donor charge density or shift in the flat-band potential, which favors charge separation.

  5. Progressive addition lens design by optimizing NURBS surface

    NASA Astrophysics Data System (ADS)

    Liu, Yen-Liang; Hsu, Wei-Yao; Cheng, Yuan-Chieh; Su, Guo-Dung

    2011-10-01

    Progressive addition lenses (PAL) are used to compensate presbyopia, which is induced by losing accommodation of elder eyes. These eyes need different optical power provided by eye glasses while watching objects at different distance. A smaller optical power is required in further distance and a larger one in nearer zone. A progressive addition lens can provides different power requirements in one piece of lens. This paper introduces a whole process of PAL production, from design, fabrication, to measurement. The PAL is designed by optimizing NURBS surface. Parameters of merit function are adjusted to design lenses with different specifications. The simulation results confirm that the power distributes as expected and cylinders are controlled under an acceptable level. Besides, sample lenses have been fabricated and measured. We apply precise-machining to produce the molds for plastic injection. Then, the samples are produced by injecting polycorbonate to the molds. Finally, Ultra Accuracy 3D Profilemeter is used to measure the sample PALs. Practical examinations shows that our designs are achievable and feasible in practice use.

  6. Water surface capturing by image processing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An alternative means of measuring the water surface interface during laboratory experiments is processing a series of sequentially captured images. Image processing can provide a continuous, non-intrusive record of the water surface profile whose accuracy is not dependent on water depth. More trad...

  7. Activities affecting surface water resources: A general overview

    SciTech Connect

    Not Available

    1990-01-01

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

  8. Ground water and surface water; a single resource

    USGS Publications Warehouse

    Winter, Thomas C.; Harvey, Judson W.; Franke, O. Lehn; Alley, William M.

    1998-01-01

    The importance of considering ground water and surface water as a single resource has become increasingly evident. Issues related to water supply, water quality, and degradation of aquatic environments are reported on frequently. The interaction of ground water and surface water has been shown to be a significant concern in many of these issues. Contaminated aquifers that discharge to streams can result in long-term contamination of surface water; conversely, streams can be a major source of contamination to aquifers. Surface water commonly is hydraulically connected to ground water, but the interactions are difficult to observe and measure. The purpose of this report is to present our current understanding of these processes and activities as well as limitations in our knowledge and ability to characterize them.

  9. Claisen-type addition of glycine to pyridoxal in water.

    PubMed

    Toth, Krisztina; Amyes, Tina L; Richard, John P; Malthouse, J Paul G; NíBeilliú, Máire E

    2004-09-01

    The reaction between 5'-deoxypyridoxal and glycine in D2O buffered at pD 7.0 does not result in significant formation of the expected products of pyridoxal-catalyzed transamination or deuterium exchange of the alpha-amino protons of glycine, but rather gives a quantitative yield of the two diastereomeric products of the formal Claisen-type addition of glycine to 5'-deoxypyridoxal. The unexpected extensive formation of these products reflects the extraordinary selectivity of the 5'-deoxypyridoxal-stabilized glycine enolate toward addition to the carbonyl group of 5'-deoxypyridoxal in the protic solvent water.

  10. Bacteriophages as surface and ground water tracers

    NASA Astrophysics Data System (ADS)

    Rossi, P.; Dörfliger, N.; Kennedy, K.; Müller, I.; Aragno, M.

    Bacteriophages are increasingly used as tracers for quantitative analysis in both hydrology and hydrogeology. The biological particles are neither toxic nor pathogenic for other living organisms as they penetrate only a specific bacterial host. They have many advantages over classical fluorescent tracers and offer the additional possibility of multi-point injection for tracer tests. Several years of research make them suitable for quantitative transport analysis and flow boundary delineation in both surface and ground waters, including karst, fractured and porous media aquifers. This article presents the effective application of bacteriophages based on their use in differing Swiss hydrological environments and compares their behaviour to conventional coloured dye or salt-type tracers. In surface water and karst aquifers, bacteriophages travel at about the same speed as the typically referenced fluorescent tracers (uranine, sulphurhodamine G extra). In aquifers of interstitial porosity, however, they appear to migrate more rapidly than fluorescent tracers, albeit with a significant reduction in their numbers within the porous media. This faster travel time implies that a modified rationale is needed for defining some ground water protection area boundaries. Further developments of other bacteriophages and their documentation as tracer methods should result in an accurate and efficient tracer tool that will be a proven alternative to conventional fluorescent dyes.

  11. 21 CFR 173.310 - Boiler water additives.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...), pp. 744-745, which is incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51... accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies are available from the National Academy Press, 2101... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Boiler water additives. 173.310 Section...

  12. 21 CFR 173.310 - Boiler water additives.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...), pp. 744-745, which is incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51... accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies are available from the National Academy Press, 2101... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Boiler water additives. 173.310 Section...

  13. 21 CFR 173.310 - Boiler water additives.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...), pp. 744-745, which is incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51... accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies are available from the National Academy Press, 2101... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Boiler water additives. 173.310 Section...

  14. 21 CFR 173.310 - Boiler water additives.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...), pp. 744-745, which is incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51... accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies are available from the National Academy Press, 2101... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Boiler water additives. 173.310 Section...

  15. Streaks Of Colored Water Indicate Surface Airflows

    NASA Technical Reports Server (NTRS)

    Wilcox, Floyd J., Jr.

    1994-01-01

    Response faster and contamination less than in oil-flow technique. Flowing colored water provides accurate and clean way to reveal flows of air on surfaces of models in wind tunnels. Colored water flows from small orifices in model, forming streak lines under influence of air streaming over surface of model.

  16. Layers of Porous Superhydrophobic Surfaces for Robust Water Repellency

    NASA Astrophysics Data System (ADS)

    Ahmadi, Farzad; Boreyko, Jonathan; Nature-Inspired Fluids; Interfaces Team

    2015-11-01

    In nature, birds exhibit multiple layers of superhydrophobic feathers that repel water. Inspired by bird feathers, we utilize porous superhydrophobic surfaces and compare the wetting and dewetting characteristics of a single surface to stacks of multiple surfaces. The superhydrophobic surfaces were submerged in water in a closed chamber. Pressurized gas was regulated to measure the critical pressure for the water to fully penetrate through the surfaces. In addition to using duck feathers, two-tier porous superhydrophobic surfaces were fabricated to serve as synthetic mimics with a controlled surface structure. The energy barrier for the wetting transition was modeled as a function of the number of layers and their orientations with respect to each other. Moreover, after partial impalement into a subset of the superhydrophobic layers, it was observed that a full dewetting transition was possible, which suggests that natural organisms can exploit their multiple layers to prevent irreversible wetting.

  17. Investigation of surface water behavior during glaze ice accretion

    NASA Technical Reports Server (NTRS)

    Hansman, R. John, Jr.; Turnock, Stephen R.

    1990-01-01

    A series of experimental investigations that focused on isolating the primary factors that control the behavior of unfrozen surface water during glaze ice accretion were conducted. Detailed microvideo observations were made of glaze ice accretions on 2.54 cm diam cylinders in a closed-loop refrigerated wind tunnel. Distinct zones of surface water behavior were observed; a smooth wet zone in the stagnation region with a uniform water film, a rough zone where surface tension effects caused coalescence of surface water into stationary beads, and a zone where surface water ran back as rivulets. The location of the transition from the smooth to the rough zone was found to migrate towards the stagnation point with time. Comparative tests were conducted to study the effect of the substrate thermal and roughness properties on ice accretion. The importance of surface water behavior was evaluated by the addition of a surface tension reducing agent to the icing tunnel water supply, which significantly altered the accreted glaze ice shape. Measurements were made to determine the contact angle behavior of water droplets on ice. A simple multizone modification to current glaze ice accretion models was proposed to include the observed surface roughness behavior.

  18. Gray solitons on the surface of water.

    PubMed

    Chabchoub, A; Kimmoun, O; Branger, H; Kharif, C; Hoffmann, N; Onorato, M; Akhmediev, N

    2014-01-01

    The dynamics of surface gravity water waves can be described by the self-defocusing nonlinear Schrödinger equation. Recent observations of black solitons on the surface of water confirmed its validity for finite, below critical depth. The black soliton is a limiting case of a family of gray soliton solutions with finite amplitude depressions. Here, we report observations of gray solitons in water waves, thus, complementing our previous observations of black solitons. PMID:24580162

  19. Pesticide mitigation strategies for surface water quality

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pesticide residues are being increasingly detected in surface water in agricultural and urban areas. In some cases water bodies are being listed under the Clean Water Act 303(d) as impaired and Total Maximum Daily Loads are required to address the impairments in agricultural areas. Pesticides in sur...

  20. Tribological Behaviour of Surface Modified Copper Nanoparticles as lubricating Additives

    NASA Astrophysics Data System (ADS)

    Shi, P. J.; Yu, H. L.; Wang, H. M.; Xu, B. S.

    A special kind of surface modified copper nanoparticles was selected as the auto-reconditioning materials to in situ generate a copperized protective film on iron-base metal surfaces under designed tribological conditions. The morphologies and element distributions of the formed film were observed and determined by scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). The micro mechanical properties and tribological behaviors were investigated by nano test system and ball- on-disc tribotester. The results show that the morphology of the protective film is smooth, the nano-hardness decreases by 46% and the friction coefficient of the copperized protective film is about 0.10. The forming mechanism of the auto-reconditioning film can be described that the copper nanoparticles deposit on the worn surfaces and form iron-copper alloy film with lower hardness and shear strength, which has better friction-reducing, antiwear and surface-optimizing behaviors.

  1. IDENTIFYING VULNERABLE SURFACE WATER UTILITIES

    EPA Science Inventory

    This study was conducted to provide a mechanism and framework with which utility managers could analyze the effects of upstream discharges on source waters. Specific components of the project included selection, implementation, and demonstration of a microcomputer-based commerci...

  2. Additives

    NASA Technical Reports Server (NTRS)

    Smalheer, C. V.

    1973-01-01

    The chemistry of lubricant additives is discussed to show what the additives are chemically and what functions they perform in the lubrication of various kinds of equipment. Current theories regarding the mode of action of lubricant additives are presented. The additive groups discussed include the following: (1) detergents and dispersants, (2) corrosion inhibitors, (3) antioxidants, (4) viscosity index improvers, (5) pour point depressants, and (6) antifouling agents.

  3. Modeled heating and surface erosion comparing motile (gas borne) and stationary (surface coating) inert particle additives

    SciTech Connect

    Buckingham, A.C.; Siekhaus, W.J.

    1982-09-27

    The unsteady, non-similar, chemically reactive, turbulent boundary layer equations are modified for gas plus dispersed solid particle mixtures, for gas phase turbulent combustion reactions and for heterogeneous gas-solid surface erosive reactions. The exterior (ballistic core) edge boundary conditions for the solutions are modified to include dispersed particle influences on core propellant combustion-generated turbulence levels, combustion reactants and products, and reaction-induced, non-isentropic mixture states. The wall surface (in this study it is always steel) is considered either bare or coated with a fixed particle coating which is conceptually non-reactive, insulative, and non-ablative. Two families of solutions are compared. These correspond to: (1) consideration of gas-borne, free-slip, almost spontaneously mobile (motile) solid particle additives which influence the turbulent heat transfer at the uncoated steel surface and, in contrast, (2) consideration of particle-free, gas phase turbulent heat transfer to the insulated surface coated by stationary particles. Significant differences in erosive heat transfer are found in comparing the two families of solutions over a substantial range of interior ballistic flow conditions. The most effective influences on reducing erosive heat transfer appear to favor mobile, gas-borne particle additives.

  4. A Review of Surface Water Quality Models

    PubMed Central

    Li, Shibei; Jia, Peng; Qi, Changjun; Ding, Feng

    2013-01-01

    Surface water quality models can be useful tools to simulate and predict the levels, distributions, and risks of chemical pollutants in a given water body. The modeling results from these models under different pollution scenarios are very important components of environmental impact assessment and can provide a basis and technique support for environmental management agencies to make right decisions. Whether the model results are right or not can impact the reasonability and scientificity of the authorized construct projects and the availability of pollution control measures. We reviewed the development of surface water quality models at three stages and analyzed the suitability, precisions, and methods among different models. Standardization of water quality models can help environmental management agencies guarantee the consistency in application of water quality models for regulatory purposes. We concluded the status of standardization of these models in developed countries and put forward available measures for the standardization of these surface water quality models, especially in developing countries. PMID:23853533

  5. Surface Water Treatment Workshop Manual.

    ERIC Educational Resources Information Center

    Ontario Ministry of the Environment, Toronto.

    This manual was developed for use at workshops designed to increase the knowledge of experienced water treatment plant operators. Each of the fourteen lessons in this document has clearly stated behavioral objectives to tell the trainee what he should know or do after completing that topic. Areas covered in this manual include: basic water…

  6. Water vapor retrieval over many surface types

    SciTech Connect

    Borel, C.C.; Clodius, W.C.; Johnson, J.

    1996-04-01

    In this paper we present a study of of the water vapor retrieval for many natural surface types which would be valuable for multi-spectral instruments using the existing Continuum Interpolated Band Ratio (CIBR) for the 940 nm water vapor absorption feature. An atmospheric code (6S) and 562 spectra were used to compute the top of the atmosphere radiance near the 940 nm water vapor absorption feature in steps of 2.5 nm as a function of precipitable water (PW). We derive a novel technique called ``Atmospheric Pre-corrected Differential Absorption`` (APDA) and show that APDA performs better than the CIBR over many surface types.

  7. Shallow water sound propagation with surface waves.

    PubMed

    Tindle, Chris T; Deane, Grant B

    2005-05-01

    The theory of wavefront modeling in underwater acoustics is extended to allow rapid range dependence of the boundaries such as occurs in shallow water with surface waves. The theory allows for multiple reflections at surface and bottom as well as focusing and defocusing due to reflection from surface waves. The phase and amplitude of the field are calculated directly and used to model pulse propagation in the time domain. Pulse waveforms are obtained directly for all wavefront arrivals including both insonified and shadow regions near caustics. Calculated waveforms agree well with a reference solution and data obtained in a near-shore shallow water experiment with surface waves over a sloping bottom.

  8. Evidence for water structuring forces between surfaces

    SciTech Connect

    Stanley, Christopher B; Rau, Dr. Donald

    2011-01-01

    Structured water on apposing surfaces can generate significant energies due to reorganization and displacement as the surfaces encounter each other. Force measurements on a multitude of biological structures using the osmotic stress technique have elucidated commonalities that point toward an underlying hydration force. In this review, the forces of two contrasting systems are considered in detail: highly charged DNA and nonpolar, uncharged hydroxypropyl cellulose. Conditions for both net repulsion and attraction, along with the measured exclusion of chemically different solutes from these macromolecular surfaces, are explored and demonstrate features consistent with a hydration force origin. Specifically, the observed interaction forces can be reduced to the effects of perturbing structured surface water.

  9. Subsurface And Surface Water Flow Interactions

    EPA Science Inventory

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

  10. Surface processing using water cluster ion beams

    NASA Astrophysics Data System (ADS)

    Takaoka, Gikan H.; Ryuto, Hiromichi; Takeuchi, Mitsuaki; Ichihashi, Gaku

    2013-07-01

    Vaporized water clusters were produced by an adiabatic expansion phenomenon, and various substrates such as Si(1 0 0), SiO2, polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), and polycarbonate (PC) were irradiated by water cluster ion beams. The sputtered depth increased with increasing acceleration voltage, and the sputtering rate was much larger than that obtained using Ar monomer ion irradiation. The sputtering yield for PMMA was approximately 200 molecules per ion, at an acceleration voltage of 9 kV. X-ray photoelectron spectroscopy (XPS) measurements showed that high-rate sputtering for the PMMA surface can be ascribed to the surface erosion by the water cluster ion irradiation. Furthermore, the micropatterning was demonstrated on the PMMA substrate. Thus, the surface irradiation by water cluster ion beams exhibited a chemical reaction based on OH radicals, as well as excited hydrogen atoms, which resulted in a high sputtering rate and low irradiation damage of the substrate surfaces.

  11. Effect of ionic additive on pool boiling critical heat flux of titania/water nanofluids

    NASA Astrophysics Data System (ADS)

    Jung, Jung-Yeul; Kim, Hyungdae; Kim, Moo Hwan

    2013-01-01

    TiO2/water nanofluids were prepared and tested to investigate the effects of an ionic additive (i.e., nitric acid in this study) on the critical heat flux (CHF) behavior in pool boiling. Experimental results showed that the ionic additive improved the dispersion stability but reduced the CHF increase in the nanofluid. The additive affected the self-assembled nanoparticle structures formed on the heater surfaces by creating a more uniform and smoother structure, thus diminishing the CHF enhancement in nanofluids.

  12. Toward a mechanistic understanding of the effect of biochar addition on soil water retention

    NASA Astrophysics Data System (ADS)

    Yi, S.; Chang, N.; Guo, M.; Imhoff, P. T.

    2014-12-01

    Biochar (BC) is a carbon-rich product produced by thermal degradation of biomass in an oxygen-free environment, whose application to sediment is said to improve water retention. However, BC produced from different feedstocks and pyrolyzed at different temperatures have distinct properties, which may alter water retention in ways difficult to predict a priori. Our goal is to develop a mechanistic understanding of BC addition on water retention by examining the impact of BC from two feedstocks, poultry litter (PL) and hardwood (HW), on the soil-water retention curves (SWRC) of a uniform sand and a sandy loam (SL). For experiments with sand, BC and sand were sieved to the same particle size (~ 0.547 mm) to minimize effects of BC addition on particle size distribution. Experiments with SL contained the same sieved BC. PL and HW bicohars were added at 2 and 7% (w/w), and water retention was measured from 0 to -4.38 × 106 cm-H2O. Both BCs increased porosities for sand and SL, up to 39 and 13% for sand and SL, respectively, with 7% HW BC addition. The primary cause for these increases was the internal porosity of BC particles. While the matric potential for air-entry was unchanged with BC addition, BC amendment increased water retention for sand and SL in the capillary region (0 to -15,000 cm-H2O) by an average of 26 and 33 % for 7% PL and HW BC in sand, respectively, but only 7 and 14 % for 7% PL and HW BC in SL. The most dramatic influence of BC amendment on water retention occurred in the adsorption region (< -15,000 cm-H2O), where water retention increased by a factor of 11 and 22 for 7% PL and HW BC in sand, respectively, but by 140 and 190 % for 7% PL and HW BC in SL, respectively. The impact of BC on water retention in these sediments is explained primarily by the additional surface area and internal porosity of PL and HW BC particles. van Genuchten (VG) models were fitted to the water retention data. For SL where the impact of BC addition on water retention was

  13. Aflatoxin Toxicity Reduction in Feed by Enhanced Binding to Surface-Modified Clay Additives

    PubMed Central

    Jaynes, William F.; Zartman, Richard E.

    2011-01-01

    Animal feeding studies have demonstrated that clay additives, such as bentonites, can bind aflatoxins in ingested feed and reduce or eliminate the toxicity. Bentonite deposits are found throughout the world and mostly consist of expandable smectite minerals, such as montmorillonite. The surfaces of smectite minerals can be treated with organic compounds to create surface-modified clays that more readily bind some contaminants than the untreated clay. Montmorillonites treated with organic cations, such as hexadecyltrimethylammonium (HDTMA) and phenyltrimethylammonium (PTMA), more effectively remove organic contaminants, such as benzene and toluene, from water than untreated clay. Similarly, montmorillonite treated with PTMA (Kd = 24,100) retained more aflatoxin B1 (AfB1) from aqueous corn flour than untreated montmorillonite (Kd = 944). Feed additives that reduced aflatoxin toxicity in animal feeding studies adsorbed more AfB1 from aqueous corn flour than feed additives that were less effective. The organic cations HDTMA and PTMA are considered toxic and would not be suitable for clay additives used in feed or food, but other non-toxic or nutrient compounds can be used to prepare surface-modified clays. Montmorillonite (SWy) treated with choline (Kd = 13,800) and carnitine (Kd = 3960) adsorbed much more AfB1 from aqueous corn flour than the untreated clay (Kd = 944). A choline-treated clay prepared from a reduced-charge, high-charge montmorillonite (Kd = 20,100) adsorbed more AfB1 than the choline-treated high-charge montmorillonite (Kd = 1340) or the untreated montmorillonite (Kd = 293). Surface-modified clay additives prepared using low-charge smectites and nutrient or non-toxic organic compounds might be used to more effectively bind aflatoxins in contaminated feed or food and prevent toxicity. PMID:22069725

  14. Water resources data, New Jersey, water year 2005. Volume 1 - surface-water data

    USGS Publications Warehouse

    White, B.T.; Hoppe, H.L.; Centinaro, G.L.; Dudek, J.F.; Painter, B.S.; Protz, A.R.; Reed, T.J.; Shvanda, J.C.; Watson, A.F.

    2006-01-01

    Water-resources data for the 2005 water year for New Jersey are presented in three volumes, and consists of records of stage, discharge, and water-quality of streams; stage and contents of lakes and reservoirs; and water levels and water-quality of ground water. Volume 1 contains discharge records for 103 gaging stations; tide summaries at 28 tidal gaging stations; stage and contents at 34 lakes and reservoirs; and diversions from 50 surface-water sources. Also included are stage and discharge for 116 crest-stage partial-record stations, stage-only at 33 tidal crest-stage gages, and discharge for 155 low-flow partial-record stations. Locations of these sites are shown in figures 8-11. Additional discharge measurements were made at 222 miscellaneous sites that are not part of the systematic data-collection program. Discontinued station tables for gaging stations, crest-stage gages, tidal crest-stage and tidal gaging stations show historical coverage. The data in this report represent that part of the National Water Information System (NWIS) data collected by the United States Geological Survey (USGS). Hydrologic conditions are also described for this water year, including stream-flow, precipitation, reservoir conditions, and air temperatures.

  15. Autocatalytic dissociation of water at stepped transition metal surfaces

    NASA Astrophysics Data System (ADS)

    Pekoez, Rengin; Woerner, Swenja; Ghiringhelli, Luca M.; Donadio, Davide

    2014-03-01

    By means of density functional theory calculations, we investigate the adsorption and dissociation of water clusters on flat and stepped surfaces of several transition metals: Rh, Ir, Pd, Pt, and Ru. We find that water binds preferentially to the edge of the steps than to terrace sites, so that isolated clusters or one-dimensional water wires can be isolated by differential desorption. The enhanced reactivity of metal atoms at the step edge and the cooperative effect of hydrogen bonding enhance the chances of partial dissociation of water clusters on stepped surfaces. For example, water dissociation on Pt and Ir surface turns from endothermic at terraces to exothermic at steps. The interpretation of water dissociation is achieved by analyzing changes in the electronic structure of both water and metals, especially focusing on the interaction between the lone-pair electrons of water and the d-band of the metals. The shift in the energetics of water dissociation at steps is expected to play a prominent role in catalysis and fuel cells reactions, as the density of steps at surfaces could be an additional parameter to design more efficient anode materials or catalytic substrates.

  16. Benefits of neutral electrolyzed oxidizing water as a drinking water additive for broiler chickens.

    PubMed

    Bügener, E; Kump, A Wilms-Schulze; Casteel, M; Klein, G

    2014-09-01

    In the wake of discussion about the use of drugs in food-producing farms, it seems to be more and more important to search for alternatives and supportive measures to improve health. In this field trial, the influence of electrolyzed oxidizing (EO) water on water quality, drug consumption, mortality, and performance parameters such as BW and feed conversion rate was investigated on 2 broiler farms. At each farm, 3 rearing periods were included in the study. With EO water as the water additive, the total viable cell count and the number of Escherichia coli in drinking water samples were reduced compared with the respective control group. The frequency of treatment days was represented by the number of used daily doses per population and showed lower values in EO-water-treated groups at both farms. Furthermore, the addition of EO water resulted in a lower mortality rate. In terms of analyzed performance parameters, no significant differences were determined. In this study, the use of EO water improved drinking water quality and seemed to reduce the drug use without showing negative effects on performance parameters and mortality rates. PMID:25037820

  17. Benefits of neutral electrolyzed oxidizing water as a drinking water additive for broiler chickens.

    PubMed

    Bügener, E; Kump, A Wilms-Schulze; Casteel, M; Klein, G

    2014-09-01

    In the wake of discussion about the use of drugs in food-producing farms, it seems to be more and more important to search for alternatives and supportive measures to improve health. In this field trial, the influence of electrolyzed oxidizing (EO) water on water quality, drug consumption, mortality, and performance parameters such as BW and feed conversion rate was investigated on 2 broiler farms. At each farm, 3 rearing periods were included in the study. With EO water as the water additive, the total viable cell count and the number of Escherichia coli in drinking water samples were reduced compared with the respective control group. The frequency of treatment days was represented by the number of used daily doses per population and showed lower values in EO-water-treated groups at both farms. Furthermore, the addition of EO water resulted in a lower mortality rate. In terms of analyzed performance parameters, no significant differences were determined. In this study, the use of EO water improved drinking water quality and seemed to reduce the drug use without showing negative effects on performance parameters and mortality rates.

  18. Stable water layers on solid surfaces.

    PubMed

    Hong, Ying-Jhan; Tai, Lin-Ai; Chen, Hung-Jen; Chang, Pin; Yang, Chung-Shi; Yew, Tri-Rung

    2016-02-17

    Liquid layers adhered to solid surfaces and that are in equilibrium with the vapor phase are common in printing, coating, and washing processes as well as in alveoli in lungs and in stomata in leaves. For such a liquid layer in equilibrium with the vapor it faces, it has been generally believed that, aside from liquid lumps, only a very thin layer of the liquid, i.e., with a thickness of only a few nanometers, is held onto the surface of the solid, and that this adhesion is due to van der Waals forces. A similar layer of water can remain on the surface of a wall of a microchannel after evaporation of bulk water creates a void in the channel, but the thickness of such a water layer has not yet been well characterized. Herein we showed such a water layer adhered to a microchannel wall to be 100 to 170 nm thick and stable against surface tension. The water layer thickness was measured using electron energy loss spectroscopy (EELS), and the water layer structure was characterized by using a quantitative nanoparticle counting technique. This thickness was found for channel gap heights ranging from 1 to 5 μm. Once formed, the water layers in the microchannel, when sealed, were stable for at least one week without any special care. Our results indicate that the water layer forms naturally and is closely associated only with the surface to which it adheres. Our study of naturally formed, stable water layers may shed light on topics from gas exchange in alveoli in biology to the post-wet-process control in the semiconductor industry. We anticipate our report to be a starting point for more detailed research and understanding of the microfluidics, mechanisms and applications of gas-liquid-solid systems. PMID:26856872

  19. Quality of surface waters in Wilton, Connecticut

    USGS Publications Warehouse

    Kulp, K.P.

    1982-01-01

    Water, bed material, and biological samples were collected and analyzed at 10 surface-water gaging sites on six streams in the town of Wilton, Connecticut over a 2-year period. The data indicate fair to excellent water quality. Fecal coliform bacteria, pH, alkalinity, iron, and manganese are the parameters that most often exceed recommended limits established by either the U. S. Environmental Protection Agency or the Connecticut Department of Environmental Protection. Data from sites on the Norwalk and East Branch Silvermine Rivers indicate little if any undesirable changes in water quality take place as they flow through the study area. (USGS)

  20. Surface water resources issues analysis: Wheeler Reservoir watershed region

    SciTech Connect

    Cox, J.P.

    1990-02-01

    This report is one in a continuing series of periodic water resources issues analyses (WRIAs) conducted within the various local drainage basins that comprise the larger Tennessee River drainage basin. These analyses, based primarily upon existing information gathered from a variety of sources, perform several functions: document known or probable water quality issues that should be addressed by TVA or others; identify specific needs for additional information; guide routine surface water monitoring programs; and provide focus for planning and setting priorities for subsequent water quality assessments, mitigative activities, and resource management projects. 4 refs., 1 fig., 16 tabs.

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

    USGS Publications Warehouse

    Lorens, J.A.

    1982-01-01

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

  2. Free energy calculation of water addition coupled to reduction of aqueous RuO4-

    NASA Astrophysics Data System (ADS)

    Tateyama, Yoshitaka; Blumberger, Jochen; Ohno, Takahisa; Sprik, Michiel

    2007-05-01

    Free energy calculations were carried out for water addition coupled reduction of aqueous ruthenate, RuO4-+H2O +e-→[RuO3(OH)2]2-, using Car-Parrinello molecular dynamics simulations. The full reaction is divided into the reduction of the tetrahedral monoanion, RuO4-+e-→RuO42-, followed by water addition, RuO42-+H2O →[RuO3(OH)2]2-. The free energy of reduction is computed from the fluctuations of the vertical energy gap using the MnO4-+e -→MnO42- reaction as reference. The free energy for water addition is estimated using constrained molecular dynamics methods. While the description of this complex reaction, in principle, involves multiple reaction coordinates, we found that reversible transformation of the reactant into the product can be achieved by control of a single reaction coordinate consisting of a suitable linear combination of atomic distances. The free energy difference of the full reaction is computed to be -0.62eV relative to the normal hydrogen electrode. This is in good agreement with the experimental value of -0.59eV, lending further support to the hypothesis that, contrary to the ruthenate monoanion, the dianion is not tetrahedral but forms a trigonal-bipyramidal dihydroxo complex in aqueous solution. We construct an approximate two-dimensional free energy surface using the coupling parameter for reduction and the mechanical constraint for water addition as variables. Analyzing this surface we find that in the most favorable reaction pathway the reduction reaction precedes water addition. The latter takes place via the protonated complex [RuO3(OH)]- and subsequent transport of the created hydroxide ion to the fifth coordination site of Ru.

  3. Influence of microwaves on the water surface tension.

    PubMed

    Parmar, Harisinh; Asada, Masahiro; Kanazawa, Yushin; Asakuma, Yusuke; Phan, Chi M; Pareek, Vishnu; Evans, Geoffrey M

    2014-08-26

    In this study, microwave irradiation was applied to hanging droplets of both water and ethylene glycol. Once the irradiation had ceased and the droplet was allowed to return to its original temperature, it was found that the surface tension of ethylene glycol returned to its original value. In contrast, the water surface tension remained well below its original value for an extended period of time. Similar observations have been reported for magnetically treated water, but this is the first time that such a lasting effect has been reported for microwave irradiation. The effect can be attributed to the unique hydrogen bonds of interfacial water molecules. While the irradiation intensities used in this study are well above those in household devices, there is certainly the potential to apply the methodology to industrial applications where the manipulation of surface tension is required without the use of chemical addition.

  4. The utility of surface temperature measurements for the remote sensing of surface soil water status

    NASA Technical Reports Server (NTRS)

    Idso, S. B.; Jackson, R. D.; Reginato, R. J.; Schmugge, T. J.

    1975-01-01

    Experiments carried out on an Avondale loam soil indicated that the thermal inertia concept of soil water content detection is reasonably sound. The volumetric water contents of surface soil layers between 2 and 4 cm thick were found to be linear functions of the amplitude of the diurnal surface soil temperature wave for clear day-night periods. They were also found to be linear functions of the daily maximum value of the surface soil-air-temperature differential. Tests on three additional soils ranging from sandy loam to clay indicated that the relations determined for Avondale loam could not be accurately applied to these other soil types. When the moisture characteristic curves of each soil were used to transform water contents into pressure potentials, however, it was found that soil water pressure potential could be determined without prior knowledge of soil type, and thus its value as a potential soil water status survey tool was significantly enhanced.

  5. A Water Rich Mars Surface Mission Scenario

    NASA Technical Reports Server (NTRS)

    Hoffman, Stephen; Andrews, Alida; Joosten, Kent; Watts, Kevin

    2017-01-01

    The surface of Mars once had abundant water flowing on its surface, but now there is a general perception that this surface is completely dry. Several lines of research have shown that there are sources of potentially large quantities of water at many locations on the surface, including regions considered as candidates for future human missions. Traditionally, system designs for these human missions are constrained to tightly recycle water and oxygen, and current resource utilization strategies involve ascent vehicle oxidizer production only. But the assumption of relatively abundant extant water may change this. Several scenarios were constructed to evaluate water requirements for human Mars expeditions to assess the impact to system design if locally produced water is available. Specifically, we have assessed water resources needed for 1) ascent vehicle oxidizer and fuel production, 2) open-loop water and oxygen life support requirements along with more robust usage scenarios, and 3) crew radiation protection augmentation. In this assessment, production techniques and the associated chemistry to transform Martian water and atmosphere into these useful commodities are identified, but production mass and power requirements are left to future analyses. The figure below illustrates the type of water need assessment performed and that will be discussed. There have been several sources of feedstock material discussed in recent literature that could be used to produce these quantities of water. This paper will focus on Mars surface features that resemble glacier-like forms on Earth. Several lines of evidence indicate that some of these features are in fact buried ice, likely remnants from an earlier ice age on Mars. This paper examines techniques and hardware systems used in the polar regions of Earth to access this buried ice and withdraw water from it. These techniques and systems will be described to illustrate options available. A technique known as a Rodriguez Well

  6. Water resources data, Iowa, water year 2001, Volume 2. surface water--Missouri River basin, and ground water

    USGS Publications Warehouse

    Nalley, G.M.; Gorman, J.G.; Goodrich, R.D.; Miller, V.E.; Turco, M.J.; Linhart, S.M.

    2002-01-01

    The Water Resources Division of the U.S. Geological Survey, in cooperation with State, county, municipal, and other Federal agencies, obtains a large amount of data pertaining to the water resources of Iowa each water year. These data, accumulated during many water years, constitute a valuable data base for developing an improved understanding of the water resources of the State. To make this data readily available to interested parties outside of the Geological Survey, the data is published annually in this report series entitled “Water Resources Data - Iowa” as part of the National Water Data System. Water resources data for water year 2001 for Iowa consists of records of stage, discharge, and water quality of streams; stage and contents of lakes and reservoirs; and water levels and water quality of ground water. This report, in two volumes, contains stage or discharge records for 132 gaging stations; stage records for 9 lakes and reservoirs; water-quality records for 4 gaging stations; sediment records for 13 gaging stations; and water levels for 163 ground-water observation wells. Also included are peak-flow data for 92 crest-stage partial-record stations, water-quality data from 86 municipal wells, and precipitation data collected at 6 gaging stations and 2 precipitation sites. Additional water data were collected at various sites not included in the systematic data-collection program, and are published here as miscellaneous measurements and analyses. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating local, State, and Federal agencies in Iowa.Records of discharge or stage of streams, and contents or stage of lakes and reservoirs were first published in a series of U.S. Geological Survey water-supply papers entitled “Surface Water Supply of the United States.” Through September 30, 1960, these water-supply papers were published in an annual series; during 1961-65 and 1966-70, they

  7. Physicochemical properties of concentrated Martian surface waters

    NASA Astrophysics Data System (ADS)

    Tosca, Nicholas J.; McLennan, Scott M.; Lamb, Michael P.; Grotzinger, John P.

    2011-05-01

    Understanding the processes controlling chemical sedimentation is an important step in deciphering paleoclimatic conditions from the rock records preserved on both Earth and Mars. Clear evidence for subaqueous sedimentation at Meridiani Planum, widespread saline mineral deposits in the Valles Marineris region, and the possible role of saline waters in forming recent geomorphologic features all underscore the need to understand the physical properties of highly concentrated solutions on Mars in addition to, and as a function of, their distinct chemistry. Using thermodynamic models predicting saline mineral solubility, we generate likely brine compositions ranging from bicarbonate-dominated to sulfate-dominated and predict their saline mineralogy. For each brine composition, we then estimate a number of thermal, transport, and colligative properties using established models that have been developed for highly concentrated multicomponent electrolyte solutions. The available experimental data and theoretical models that allow estimation of these physicochemical properties encompass, for the most part, much of the anticipated variation in chemistry for likely Martian brines. These estimates allow significant progress in building a detailed analysis of physical sedimentation at the ancient Martian surface and allow more accurate predictions of thermal behavior and the diffusive transport of matter through chemically distinct solutions under comparatively nonstandard conditions.

  8. Improved surface property of PVDF membrane with amphiphilic zwitterionic copolymer as membrane additive

    NASA Astrophysics Data System (ADS)

    Li, Jian-Hua; Li, Mi-Zi; Miao, Jing; Wang, Jia-Bin; Shao, Xi-Sheng; Zhang, Qi-Qing

    2012-06-01

    An attempt to improve hydrophilicity and anti-fouling properties of PVDF membranes, a novel amphiphilic zwitterionic copolymer poly(vinylidene fluoride)-graft-poly(sulfobetaine methacrylate) (PVDF-g-PSBMA) was firstly synthesized by atom transfer radical polymerization (ATRP) and used as amphiphilic copolymer additive in the preparation of PVDF membranes. The PVDF-g-PSBMA/PVDF blend membranes were prepared by immersion precipitation process. Fourier transform infrared attenuated reflection spectroscopy (FTIR-ATR) and X-ray photoelectronic spectroscopy (XPS) measurements confirmed that PSBMA brushes from amphiphilic additives were preferentially segregated to membrane-coagulant interface during membrane formation. The morphology of membranes was characterized by scanning electron microscopy (SEM). Water contact angle measurements showed that the surface hydrophilicity of PVDF membranes was improved significantly with the increasing of amphiphilic copolymer PVDF-g-PSBMA in cast solution. Protein static adsorption experiment and dynamic fouling resistance experiment revealed that the surface enrichment of PSBMA brush endowed PVDF blend membrane great improvement of surface anti-fouling ability.

  9. Anthropogenic impacts on continental surface water fluxes

    NASA Astrophysics Data System (ADS)

    Haddeland, Ingjerd; Skaugen, Thomas; Lettenmaier, Dennis P.

    2006-04-01

    Impacts of reservoirs and irrigation water withdrawals on continental surface water fluxes are studied within the framework of the Variable Infiltration Capacity (VIC) model for a part of North America, and for Asia. A reservoir model, designed for continental-scale simulations, is developed and implemented in the VIC model. The model successfully simulates irrigation water requirements, and captures the main effects of reservoir operations and irrigation water withdrawals on surface water fluxes, although consumptive irrigation water use is somewhat underestimated. For the North American region, simulated irrigation water requirements and consumptive irrigation water uses are 191 and 98 km3year-1, while the corresponding numbers for the Asian region are 810 and 509 km3year-1, respectively. The consumptive uses represent a decrease in river discharge of 4.2 percent for the North American region, and 2.8 percent for the Asian region. The largest monthly decrease is about 30 percent, for the area draining the Western USA in June. The maximum monthly increase in streamflow (28 percent) is in March for the Asian Arctic region.

  10. Salty glycerol versus salty water surface organization: bromide and iodide surface propensities.

    PubMed

    Huang, Zishuai; Hua, Wei; Verreault, Dominique; Allen, Heather C

    2013-07-25

    Salty NaBr and NaI glycerol solution interfaces are examined in the OH stretching region using broadband vibrational sum frequency generation (VSFG) spectroscopy. Raman and infrared (IR) spectroscopy are used to further understand the VSFG spectroscopic signature. The VSFG spectra of salty glycerol solutions reveal that bromide and iodide anions perturb the interfacial glycerol organization in a manner similar as that found in aqueous halide salt solutions, thus confirming the presence of bromide and iodide anions at the glycerol surface. Surface tension measurements are consistent with the surface propensity suggested by the VSFG data and also show that the surface excess increases with increasing salt concentration, similar to that of water. In addition, iodide is shown to have more surface prevalence than bromide, as has also been determined from aqueous solutions. These results suggest that glycerol behaves similarly to water with respect to surface activity and solvation of halide anions at its air/liquid interface. PMID:23663033

  11. Surface properties of a single perfluoroalkyl group on water surfaces studied by surface potential measurements.

    PubMed

    Shimoaka, Takafumi; Tanaka, Yuki; Shioya, Nobutaka; Morita, Kohei; Sonoyama, Masashi; Amii, Hideki; Takagi, Toshiyuki; Kanamori, Toshiyuki; Hasegawa, Takeshi

    2016-12-01

    A discriminative study of a single perfluoroalkyl (Rf) group from a bulk material is recently recognized to be necessary toward the total understanding of Rf compounds based on a primary chemical structure. The single molecule and the bulk matter have an interrelationship via an intrinsic two-dimensional (2D) aggregation property of an Rf group, which is theorized by the stratified dipole-arrays (SDA) theory. Since an Rf group has dipole moments along many C-F bonds, a single Rf group would possess a hydrophilic-like character on the surface. To reveal the hydration character of a single Rf group, in the present study, surface potential (ΔV) measurements are performed for Langmuir monolayers of Rf-containing compounds. From a comparative study with a monolayer of a normal hydrocarbon compound, the hydration/dehydration dynamics of a lying Rf group on water has first been monitored by ΔV measurements, through which a single Rf group has been revealed to have a unique "dipole-interactive" character, which enables the Rf group interacted with the water 'surface.' In addition, the SDA theory proves to be useful to predict the 2D aggregation property across the phase transition temperature of 19°C by use of the ΔV measurements.

  12. Surface properties of a single perfluoroalkyl group on water surfaces studied by surface potential measurements.

    PubMed

    Shimoaka, Takafumi; Tanaka, Yuki; Shioya, Nobutaka; Morita, Kohei; Sonoyama, Masashi; Amii, Hideki; Takagi, Toshiyuki; Kanamori, Toshiyuki; Hasegawa, Takeshi

    2016-12-01

    A discriminative study of a single perfluoroalkyl (Rf) group from a bulk material is recently recognized to be necessary toward the total understanding of Rf compounds based on a primary chemical structure. The single molecule and the bulk matter have an interrelationship via an intrinsic two-dimensional (2D) aggregation property of an Rf group, which is theorized by the stratified dipole-arrays (SDA) theory. Since an Rf group has dipole moments along many C-F bonds, a single Rf group would possess a hydrophilic-like character on the surface. To reveal the hydration character of a single Rf group, in the present study, surface potential (ΔV) measurements are performed for Langmuir monolayers of Rf-containing compounds. From a comparative study with a monolayer of a normal hydrocarbon compound, the hydration/dehydration dynamics of a lying Rf group on water has first been monitored by ΔV measurements, through which a single Rf group has been revealed to have a unique "dipole-interactive" character, which enables the Rf group interacted with the water 'surface.' In addition, the SDA theory proves to be useful to predict the 2D aggregation property across the phase transition temperature of 19°C by use of the ΔV measurements. PMID:27569518

  13. Burning of suspended coal-water slurry droplet with oil as combustion additive. Final report

    SciTech Connect

    Yao, S.C.

    1984-10-01

    The combustion of single coal-water slurry droplet with oil as combustion additive (CWOM) has been studied. In this study, the droplet is suspended on a fine quartz fiber and is exposed to the hot combustion product of propane (C/sub 3/H/sub 8/) and air. The results are documented in a movie series. The combustion of CWOM with various combinations of concentrations are compared with that of coal-water slurry and water-oil mixture droplets. The combustion of coal-water slurry is enhanced significantly due to the presence of emulsified kerosene. The enhancement is also dependent upon the mixing procedure during preparation of CWOM. The presence of emulsified kerosene induces local boil-off and combustion that coal particles are splashed as fire works during the early evaporation stage of droplet heat-up. After particle splashing, blow-holes appear on the droplet surface. The popcorn and swelling phenomena usually occurred in coal-water-slurry combustion is greatly reduced. Significant combustion enhancement occurs with the use of kerosene in an amount of about 15 percent of the overall CWOM. This process of using kerosene as combustion additive may provide obvious advantage for the combustion of bituminous coal-water slurry. 4 references, 6 figures.

  14. Using water isotopes in the evaluation of land surface models

    NASA Astrophysics Data System (ADS)

    Guglielmo, Francesca; Risi, Camille; Ottlé, Catherine; Bastrikov, Vladislav; Valdayskikh, Victor; Cattani, Olivier; Jouzel, Jean; Gribanov, Konstantin; Nekrasova, Olga; Zacharov, Vyacheslav; Ogée, Jérôme; Wingate, Lisa; Raz-Yaseef, Naama

    2013-04-01

    Several studies show that uncertainties in the representation of land surface processes contribute significantly to the spread in projections for the hydrological cycle. Improvements in the evaluation of land surface models would therefore translate into more reliable predictions of future changes. The isotopic composition of water is affected by phase transitions and, for this reason, is a good tracer for the hydrological cycle. Particularly relevant for the assessment of land surface processes is the fact that bare soil evaporation and transpiration bear different isotopic signatures. Water isotopic measurement could thus be employed in the evaluation of the land surface hydrological budget. With this objective, isotopes have been implemented in the most recent version of the land surface model ORCHIDEE. This model has undergone considerable development in the past few years. In particular, a newly discretised (11 layers) hydrology aims at a more realistic representation of the soil water budget. In addition, biogeophysical processes, as, for instance, the dynamics of permafrost and of its interaction with snow and vegetation, have been included. This model version will allow us to better resolve vertical profiles of soil water isotopic composition and to more realistically simulate the land surface hydrological and isotopic budget in a broader range of climate zones. Model results have been evaluated against temperature profiles and isotopes measurements in soil and stem water at sites located in semi-arid (Yatir), temperate (Le Bray) and boreal (Labytnangi) regions. Seasonal cycles are reasonably well reproduced. Furthermore, a sensitivity analysis investigates to what extent water isotopic measurements in soil water can help constrain the representation of land surface processes, with a focus on the partitioning between evaporation and transpiration. In turn, improvements in the description of this partitioning may help reduce the uncertainties in the land

  15. Pollution of surface water in Europe

    PubMed Central

    Key, A.

    1956-01-01

    This paper discusses pollution of surface water in 18 European countries. For each an account is given of its physical character, population, industries, and present condition of water supplies; the legal, administrative, and technical means of controlling pollution are then described, and an outline is given of current research on the difficulties peculiar to each country. A general discussion of various aspects common to the European problem of water pollution follows; standards of quality are suggested; some difficulties likely to arise in the near future are indicated, and international collaboration, primarily by the exchange of information, is recommended to check or forestall these trends. PMID:13374532

  16. Global modelling of Cryptosporidium in surface water

    NASA Astrophysics Data System (ADS)

    Vermeulen, Lucie; Hofstra, Nynke

    2016-04-01

    Introduction Waterborne pathogens that cause diarrhoea, such as Cryptosporidium, pose a health risk all over the world. In many regions quantitative information on pathogens in surface water is unavailable. Our main objective is to model Cryptosporidium concentrations in surface waters worldwide. We present the GloWPa-Crypto model and use the model in a scenario analysis. A first exploration of global Cryptosporidium emissions to surface waters has been published by Hofstra et al. (2013). Further work has focused on modelling emissions of Cryptosporidium and Rotavirus to surface waters from human sources (Vermeulen et al 2015, Kiulia et al 2015). A global waterborne pathogen model can provide valuable insights by (1) providing quantitative information on pathogen levels in data-sparse regions, (2) identifying pathogen hotspots, (3) enabling future projections under global change scenarios and (4) supporting decision making. Material and Methods GloWPa-Crypto runs on a monthly time step and represents conditions for approximately the year 2010. The spatial resolution is a 0.5 x 0.5 degree latitude x longitude grid for the world. We use livestock maps (http://livestock.geo-wiki.org/) combined with literature estimates to calculate spatially explicit livestock Cryptosporidium emissions. For human Cryptosporidium emissions, we use UN population estimates, the WHO/UNICEF JMP sanitation country data and literature estimates of wastewater treatment. We combine our emissions model with a river routing model and data from the VIC hydrological model (http://vic.readthedocs.org/en/master/) to calculate concentrations in surface water. Cryptosporidium survival during transport depends on UV radiation and water temperature. We explore pathogen emissions and concentrations in 2050 with the new Shared Socio-economic Pathways (SSPs) 1 and 3. These scenarios describe plausible future trends in demographics, economic development and the degree of global integration. Results and

  17. Evaporation over fresh and saline water surfaces

    NASA Astrophysics Data System (ADS)

    Abdelrady, Ahmed; Timmermans, Joris; Vekerdy, Zoltan

    2013-04-01

    Evaporation over large water bodies has a crucial role in the global hydrological cycle. Evaporation occurs whenever there is a vapor pressure deficit between a water surface and the atmosphere, and the available energy is sufficient. Salinity affects the density and latent heat of vaporization of the water body, which reflects on the evaporation rate. Different models have been developed to estimate the evaporation process over water surfaces using earth observation data. Most of these models are concerned with the atmospheric parameters. However these models do not take into account the influence of salinity on the evaporation rate; they do not consider the difference in the energy needed for vaporization. For this purpose an energy balance model is required. Several energy balance models that calculate daily evapotranspiration exist, such as the surface energy balance system (SEBS). They estimate the heat fluxes by integration of satellite data and hydro-meteorological field data. SEBS has the advantage that it can be applied over a large scale because it incorporates the physical state of the surface and the aerodynamic resistances in the daily evapotranspiration estimation. Nevertheless this model has not used over water surfaces. The goal of this research is to adapt SEBS to estimate the daily evaporation over fresh and saline water bodies. In particular, 1) water heat flux and roughness of momentum and heat transfer estimation need to be updated, 2) upscaling to daily evaporation needs to be investigated and finally 3) integration of the salinity factor to estimate the evaporation over saline water needs to be performed. Eddy covariance measurements over the Ijsselmeer Lake (The Netherlands) were used to estimate the roughness of momentum and heat transfer at respectively 0.0002 and 0.0001 m. Application of these values over Tana Lake (freshwater), in Ethiopia showed latent heat to be in a good agreement with the measurements, with RMSE of 35.5 Wm-2and r

  18. NANOFILTRATION FOULANTS FROM A TREATED SURFACE WATER

    EPA Science Inventory

    The foulant from pilot nanofiltration membrane elements fed conventionally-treated surface water for 15 months was analyzed for organic, inorganic, and biological parameters. The foulant responsible for flux loss was shown to be a film layer 20 to 80 um thick with the greatest de...

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

    NASA Astrophysics Data System (ADS)

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

    2014-08-01

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

  20. Surface-Water Data, Georgia, Water Year 1999

    USGS Publications Warehouse

    Alhadeff, S. Jack; Landers, Mark N.; McCallum, Brian E.

    1999-01-01

    Water resources data for the 1999 water year for Georgia consists of records of stage, discharge, and water quality of streams; and the stage and contents of lakes and reservoirs published in one volume in a digital format on a CD-ROM. This volume contains discharge records of 121 gaging stations; stage for 13 gaging stations; stage and contents for 18 lakes and reservoirs; continuous water quality records for 10 stations; and the annual peak stage and annual peak discharge for 75 crest-stage partial-record stations. These data represent that part of the National Water Data System collected by the U.S. Geological Survey and cooperating State and Federal agencies in Georgia. Records of discharge and stage of streams, and contents or stage of lakes and reservoirs were first published in a series of U.S. Geological water-supply papers entitled, 'Surface-Water Supply of the United States.' Through September 30, 1960, these water-supply papers were in an annual series and then in a 5-year series for 1961-65 and 1966-70. Records of chemical quality, water temperature, and suspended sediment were published from 1941 to 1970 in an annual series of water-supply papers entitled, 'Quality of Surface Waters of the United States.' Records of ground-water levels were published from 1935 to 1974 in a series of water-supply papers entitled, 'Ground-Water Levels in the United States.' Water-supply papers may be consulted in the libraries of the principal cities in the United States or may be purchased from the U.S. Geological Survey, Branch of Information Services, Federal Center, Box 25286, Denver, CO 80225. For water years 1961 through 1970, streamflow data were released by the U.S. Geological Survey in annual reports on a State-boundary basis prior to the two 5-year series water-supply papers, which cover this period. The data contained in the water-supply papers are considered the official record. Water-quality records for water years 1964 through 1970 were similarly released

  1. Thermodynamic properties of water solvating biomolecular surfaces

    NASA Astrophysics Data System (ADS)

    Heyden, Matthias

    Changes in the potential energy and entropy of water molecules hydrating biomolecular interfaces play a significant role for biomolecular solubility and association. Free energy perturbation and thermodynamic integration methods allow calculations of free energy differences between two states from simulations. However, these methods are computationally demanding and do not provide insights into individual thermodynamic contributions, i.e. changes in the solvent energy or entropy. Here, we employ methods to spatially resolve distributions of hydration water thermodynamic properties in the vicinity of biomolecular surfaces. This allows direct insights into thermodynamic signatures of the hydration of hydrophobic and hydrophilic solvent accessible sites of proteins and small molecules and comparisons to ideal model surfaces. We correlate dynamic properties of hydration water molecules, i.e. translational and rotational mobility, to their thermodynamics. The latter can be used as a guide to extract thermodynamic information from experimental measurements of site-resolved water dynamics. Further, we study energy-entropy compensations of water at different hydration sites of biomolecular surfaces. This work is supported by the Cluster of Excellence RESOLV (EXC 1069) funded by the Deutsche Forschungsgemeinschaft.

  2. Surface Water and Ocean Topography (SWOT) mission

    NASA Astrophysics Data System (ADS)

    Neeck, Steven P.; Lindstrom, Eric J.; Vaze, Parag V.; Fu, Lee-Lueng

    2012-09-01

    The Surface Water Ocean Topography (SWOT) mission was recommended in 2007 by the National Research Council's Decadal Survey, "Earth Science and Applications from Space: National Imperatives for the Next Decade and Beyond", for implementation by NASA. The SWOT mission is a partnership between two communities, the physical oceanography and the hydrology, to share high vertical accuracy and high spatial resolution topography data produced by the science payload, principally a Ka-band radar Interferometer (KaRIn). The SWOT payload also includes a precision orbit determination system consisting of GPS and DORIS receivers, a Laser Retro-reflector Assembly (LRA), a Jason-class nadir radar altimeter, and a JASON-class radiometer for tropospheric path delay corrections. The SWOT mission will provide large-scale data sets of ocean sea-surface height resolving scales of 15km and larger, allowing the characterization of ocean mesoscale and submesoscale circulation. The SWOT mission will also provide measurements of water storage changes in terrestrial surface water bodies and estimates of discharge in large (wider than 100m) rivers globally. The SWOT measurements will provide a key complement to other NASA spaceborne global measurements of the water cycle measurements by directly measuring the surface water (lakes, reservoirs, rivers, and wetlands) component of the water cycle. The SWOT mission is an international partnership between NASA and the Centre National d'Etudes Spatiales (CNES). The Canadian Space Agency (CSA) is also expected to contribute to the mission. SWOT is currently nearing entry to Formulation (Phase A). Its launch is targeted for October 2020.

  3. Effect of addition of water-soluble chitin on amylose film.

    PubMed

    Suzuki, Shiho; Shimahashi, Katsumasa; Takahara, Junichi; Sunako, Michihiro; Takaha, Takeshi; Ogawa, Kozo; Kitamura, Shinichi

    2005-01-01

    Amylose films blended with chitosan, which were free from additives such as acid, salt, and plasticizer, were prepared by casting mixtures of an aqueous solution of an enzymatically synthesized amylose and that of water-soluble chitin (44.1% deacetylated). The presence of a small amount of chitin (less than 10%) increased significantly the permeability of gases (N2, O2, CO2, C2H4) and improved the mechanical parameters of amylose film; particularly, the elastic modulus and elongation of the blend films were larger than those of amylose or chitin films. No antibacterial activity was observed with either amylose or water-soluble chitin films. But amylose films having a small amount of chitin showed strong antibacterial action, suggesting a morphological change in water-soluble chitin on the film surface by blending with amylose molecule. These facts suggested the presence of a molecular complex of amylose and chitosan. PMID:16283751

  4. pH and the surface tension of water.

    PubMed

    Beattie, James K; Djerdjev, Alex M; Gray-Weale, Angus; Kallay, Nikola; Lützenkirchen, Johannes; Preočanin, Tajana; Selmani, Atiđa

    2014-05-15

    Despite the strong adsorption of hydroxide ions, the surface tension of water is almost independent of pH between pH 1 and 13 when the pH is adjusted by addition of HCl or NaOH. This is consistent with the Gibbs adsorption isotherm which measures the surface excess of all species in the double layer, if hydronium ions and hydroxide ions are adsorbed and sodium and chloride ions are not. The surface tension becomes pH dependent around pH 7 in millimolar NaCl or KCl solutions, for now sodium ions can replace hydronium ions as counterions to the adsorbed hydroxide ions.

  5. Exfoliated MoS2 in Water without Additives

    PubMed Central

    Forsberg, Viviane; Zhang, Renyun; Bäckström, Joakim; Dahlström, Christina; Andres, Britta; Norgren, Magnus; Andersson, Mattias; Hummelgård, Magnus; Olin, Håkan

    2016-01-01

    Many solution processing methods of exfoliation of layered materials have been studied during the last few years; most of them are based on organic solvents or rely on surfactants and other funtionalization agents. Pure water should be an ideal solvent, however, it is generally believed, based on solubility theories that stable dispersions of water could not be achieved and systematic studies are lacking. Here we describe the use of water as a solvent and the stabilization process involved therein. We introduce an exfoliation method of molybdenum disulfide (MoS2) in pure water at high concentration (i.e., 0.14 ± 0.01 g L−1). This was achieved by thinning the bulk MoS2 by mechanical exfoliation between sand papers and dispersing it by liquid exfoliation through probe sonication in water. We observed thin MoS2 nanosheets in water characterized by TEM, AFM and SEM images. The dimensions of the nanosheets were around 200 nm, the same range obtained in organic solvents. Electrophoretic mobility measurements indicated that electrical charges may be responsible for the stabilization of the dispersions. A probability decay equation was proposed to compare the stability of these dispersions with the ones reported in the literature. Water can be used as a solvent to disperse nanosheets and although the stability of the dispersions may not be as high as in organic solvents, the present method could be employed for a number of applications where the dispersions can be produced on site and organic solvents are not desirable. PMID:27120098

  6. Properties of water surface discharge at different pulse repetition rates

    SciTech Connect

    Ruma,; Yoshihara, K.; Hosseini, S. H. R. Sakugawa, T.; Akiyama, H.; Akiyama, M.; Lukeš, P.

    2014-09-28

    The properties of water surface discharge plasma for variety of pulse repetition rates are investigated. A magnetic pulse compression (MPC) pulsed power modulator able to deliver pulse repetition rates up to 1000 Hz, with 0.5 J per pulse energy output at 25 kV, was used as the pulsed power source. Positive pulse with a point-to-plane electrode configuration was used for the experiments. The concentration and production yield of hydrogen peroxide (H₂O₂) were quantitatively measured and orange II organic dye was treated, to evaluate the chemical properties of the discharge reactor. Experimental results show that the physical and chemical properties of water surface discharge are not influenced by pulse repetition rate, very different from those observed for under water discharge. The production yield of H₂O₂ and degradation rate per pulse of the dye did not significantly vary at different pulse repetition rates under a constant discharge mode on water surface. In addition, the solution temperature, pH, and conductivity for both water surface and underwater discharge reactors were measured to compare their plasma properties for different pulse repetition rates. The results confirm that surface discharge can be employed at high pulse repetition rates as a reliable and advantageous method for industrial and environmental decontamination applications.

  7. The initiation of subduction: criticality by addition of water?

    PubMed

    Regenauer-Lieb, K; Yuen, D A; Branlund, J

    2001-10-19

    Subduction is a major process of plate tectonics; however, its initiation is not understood. We used high-resolution (less than 1 kilometer) finite-element models based on rheological data of the lithosphere to investigate the role played by water on initiating subduction. A solid-fluid thermomechanical instability is needed to drive a cold, stiff, and negatively buoyant lithosphere into the mantle. This instability can be triggered slowly by sedimentary loading over a time span of 100 million years. Our results indicate that subduction can proceed by a double feedback mechanism (thermoelastic and thermal-rheological) promoted by lubrication due to water.

  8. Surface-Water and Ground-Water Resources of Kendall County, Illinois

    USGS Publications Warehouse

    Kay, Robert T.; Mills, Patrick C.; Hogan, Jennifer L.; Arnold, Terri L.

    2005-01-01

    Water-supply needs in Kendall County, in northern Illinois, are met exclusively from ground water derived from glacial drift aquifers and bedrock aquifers open to Silurian, Ordovician, and Cambrian System units. As a result of population growth in Kendall County and the surrounding area, water use has increased from about 1.2 million gallons per day in 1957 to more than 5 million gallons per day in 2000. The purpose of this report is to characterize the surface-water and ground-water resources of Kendall County. The report presents a compilation of available information on geology, surface-water and ground-water hydrology, water quality, and water use. The Fox River is the primary surface-water body in Kendall County and is used for both wastewater disposal and as a drinking-water supply upstream of the county. Water from the Fox River requires pretreatment for use as drinking water, but the river is a potentially viable additional source of water for the county. Glacial drift aquifers capable of yielding sufficient water for municipal supply are expected to be present in northern Kendall County, along the Fox River, and in the Newark Valley and its tributaries. Glacial drift aquifers capable of yielding sufficient water for residential supply are present in most of the county, with the exception of the southeastern portion. Volatile organic compounds and select trace metals and pesticides have been detected at low concentrations in glacial drift aquifers near waste-disposal sites. Agricultural-related constituents have been detected infrequently in glacial drift aquifers near agricultural areas. However, on the basis of the available data, widespread, consistent problems with water quality are not apparent in these aquifers. These aquifers are a viable source for additional water supply, but would require further characterization prior to full development. The shallow bedrock aquifer is composed of the sandstone units of the Ancell Group, the Prairie du Chien

  9. Uncertainty in surface water flood risk modelling

    NASA Astrophysics Data System (ADS)

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

    2009-04-01

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

  10. Modeling decadal timescale interactions between surface water and ground water in the central Everglades, Florida, USA

    USGS Publications Warehouse

    Harvey, J.W.; Newlin, J.T.; Krupa, S.L.

    2006-01-01

    Surface-water and ground-water flow are coupled in the central Everglades, although the remoteness of this system has hindered many previous attempts to quantify interactions between surface water and ground water. We modeled flow through a 43,000 ha basin in the central Everglades called Water Conservation Area 2A. The purpose of the model was to quantify recharge and discharge in the basin's vast interior areas. The presence and distribution of tritium in ground water was the principal constraint on the modeling, based on measurements in 25 research wells ranging in depth from 2 to 37 m. In addition to average characteristics of surface-water flow, the model parameters included depth of the layer of 'interactive' ground water that is actively exchanged with surface water, average residence time of interactive ground water, and the associated recharge and discharge fluxes across the wetland ground surface. Results indicated that only a relatively thin (8 m) layer of the 60 m deep surfical aquifer actively exchanges surface water and ground water on a decadal timescale. The calculated storage depth of interactive ground water was 3.1 m after adjustment for the porosity of peat and sandy limestone. Modeling of the tritium data yielded an average residence time of 90 years in interactive ground water, with associated recharge and discharge fluxes equal to 0.01 cm d -1. 3H/3He isotopic ratio measurements (which correct for effects of vertical mixing in the aquifer with deeper, tritium-dead water) were available from several wells, and these indicated an average residence time of 25 years, suggesting that residence time was overestimated using tritium measurements alone. Indeed, both residence time and storage depth would be expected to be overestimated due to vertical mixing. The estimate of recharge and discharge (0.01 cm d-1) that resulted from tritium modeling therefore is still considered reliable, because the ratio of residence time and storage depth (used to

  11. Silver speciation in wastewater effluent, surface waters, and pore waters

    SciTech Connect

    Adams, N.W.H.; Kramer, J.R.

    1999-12-01

    Silver, inorganic sulfide, and thiol compounds were measured in municipal wastewater effluent, receiving waters, and pore waters from an anoxic lake sediment in order to predict silver speciation in these systems. The authors found submicromolar concentrations of inorganic sulfide even in fully oxic surface water. This inorganic sulfide is likely to exist in the form of colloidal metal sulfides, which have been shown to be stable under oxidizing conditions for periods of several hours. Inorganic sulfide in both the wastewater effluent and receiving waters was found to be 200 to 300 times in excess of silver concentrations, whereas inorganic sulfide in pore waters was 1,000 to 15,000 times in excess of silver concentrations. With sulfide in excess of silver, the authors predict silver sulfide complexes to dominate silver speciation. Thiols were present at low nanomolar levels in pore waters but were not detectable in wastewater effluent or receiving waters. Thiols do not appear to be important to silver speciation in these freshwater systems. Partitioning of silver into particular, colloidal, and dissolved size fractions showed that a significant proportion of silver is in the colloidal and dissolved phases. Dissolved phase concentrations were relatively constant in the treatment plant effluent and receiving waters, suggesting that silver in the <10-kDa size fraction is strongly complexed by ligands that are not significantly affected by aggregation or sorption processes.

  12. Water droplet impact on elastic superhydrophobic surfaces.

    PubMed

    Weisensee, Patricia B; Tian, Junjiao; Miljkovic, Nenad; King, William P

    2016-01-01

    Water droplet impact on surfaces is a ubiquitous phenomenon in nature and industry, where the time of contact between droplet and surface influences the transfer of mass, momentum and energy. To manipulate and reduce the contact time of impacting droplets, previous publications report tailoring of surface microstructures that influence the droplet - surface interface. Here we show that surface elasticity also affects droplet impact, where a droplet impacting an elastic superhydrophobic surface can lead to a two-fold reduction in contact time compared to equivalent rigid surfaces. Using high speed imaging, we investigated the impact dynamics on elastic nanostructured superhydrophobic substrates having membrane and cantilever designs with stiffness 0.5-7630 N/m. Upon impact, the droplet excites the substrate to oscillate, while during liquid retraction, the substrate imparts vertical momentum back to the droplet with a springboard effect, causing early droplet lift-off with reduced contact time. Through detailed experimental and theoretical analysis, we show that this novel springboarding phenomenon is achieved for a specific range of Weber numbers (We >40) and droplet Froude numbers during spreading (Fr >1). The observation of the substrate elasticity-mediated droplet springboard effect provides new insight into droplet impact physics.

  13. Water droplet impact on elastic superhydrophobic surfaces.

    PubMed

    Weisensee, Patricia B; Tian, Junjiao; Miljkovic, Nenad; King, William P

    2016-01-01

    Water droplet impact on surfaces is a ubiquitous phenomenon in nature and industry, where the time of contact between droplet and surface influences the transfer of mass, momentum and energy. To manipulate and reduce the contact time of impacting droplets, previous publications report tailoring of surface microstructures that influence the droplet - surface interface. Here we show that surface elasticity also affects droplet impact, where a droplet impacting an elastic superhydrophobic surface can lead to a two-fold reduction in contact time compared to equivalent rigid surfaces. Using high speed imaging, we investigated the impact dynamics on elastic nanostructured superhydrophobic substrates having membrane and cantilever designs with stiffness 0.5-7630 N/m. Upon impact, the droplet excites the substrate to oscillate, while during liquid retraction, the substrate imparts vertical momentum back to the droplet with a springboard effect, causing early droplet lift-off with reduced contact time. Through detailed experimental and theoretical analysis, we show that this novel springboarding phenomenon is achieved for a specific range of Weber numbers (We >40) and droplet Froude numbers during spreading (Fr >1). The observation of the substrate elasticity-mediated droplet springboard effect provides new insight into droplet impact physics. PMID:27461899

  14. Water droplet impact on elastic superhydrophobic surfaces

    NASA Astrophysics Data System (ADS)

    Weisensee, Patricia B.; Tian, Junjiao; Miljkovic, Nenad; King, William P.

    2016-07-01

    Water droplet impact on surfaces is a ubiquitous phenomenon in nature and industry, where the time of contact between droplet and surface influences the transfer of mass, momentum and energy. To manipulate and reduce the contact time of impacting droplets, previous publications report tailoring of surface microstructures that influence the droplet - surface interface. Here we show that surface elasticity also affects droplet impact, where a droplet impacting an elastic superhydrophobic surface can lead to a two-fold reduction in contact time compared to equivalent rigid surfaces. Using high speed imaging, we investigated the impact dynamics on elastic nanostructured superhydrophobic substrates having membrane and cantilever designs with stiffness 0.5–7630 N/m. Upon impact, the droplet excites the substrate to oscillate, while during liquid retraction, the substrate imparts vertical momentum back to the droplet with a springboard effect, causing early droplet lift-off with reduced contact time. Through detailed experimental and theoretical analysis, we show that this novel springboarding phenomenon is achieved for a specific range of Weber numbers (We >40) and droplet Froude numbers during spreading (Fr >1). The observation of the substrate elasticity-mediated droplet springboard effect provides new insight into droplet impact physics.

  15. Acidification of East Siberian Arctic Shelf waters through addition of freshwater and terrestrial carbon

    NASA Astrophysics Data System (ADS)

    Semiletov, Igor; Pipko, Irina; Gustafsson, Örjan; Anderson, Leif G.; Sergienko, Valentin; Pugach, Svetlana; Dudarev, Oleg; Charkin, Alexander; Gukov, Alexander; Bröder, Lisa; Andersson, August; Spivak, Eduard; Shakhova, Natalia

    2016-05-01

    Ocean acidification affects marine ecosystems and carbon cycling, and is considered a direct effect of anthropogenic carbon dioxide uptake from the atmosphere. Accumulation of atmospheric CO2 in ocean surface waters is predicted to make the ocean twice as acidic by the end of this century. The Arctic Ocean is particularly sensitive to ocean acidification because more CO2 can dissolve in cold water. Here we present observations of the chemical and physical characteristics of East Siberian Arctic Shelf waters from 1999, 2000-2005, 2008 and 2011, and find extreme aragonite undersaturation that reflects acidity levels in excess of those projected in this region for 2100. Dissolved inorganic carbon isotopic data and Markov chain Monte Carlo simulations of water sources using salinity and δ18O data suggest that the persistent acidification is driven by the degradation of terrestrial organic matter and discharge of Arctic river water with elevated CO2 concentrations, rather than by uptake of atmospheric CO2. We suggest that East Siberian Arctic Shelf waters may become more acidic if thawing permafrost leads to enhanced terrestrial organic carbon inputs and if freshwater additions continue to increase, which may affect their efficiency as a source of CO2.

  16. Improvement of pattern collapse issue by additive-added D.I. water rinse process

    NASA Astrophysics Data System (ADS)

    Tanaka, Keiichi; Naito, Ryoichiro; Kitada, Tomohiro; Kiba, Yukio; Yamada, Yoshiaki; Kobayashi, Masakazu; Ichikawa, Hiroyuki

    2003-06-01

    Reduction of critical dimension in lithography technology is aggressively promoted. At the same time, further resist thickness reduction is being pursued to increase the resolution capabilities of resist. However, thin film has its limitation because of etch requirements etc. As that result, the promotion of reduction results in increasing the aspect ratio, which leads to pattern collapse. It is well known that at drying step in developing process the capillary effect operates the photoresist pattern. If the force of the capillary effect is greater than the aggregation force of the resist pattern, the pattern collapse is generated. And the key parameters of the capillary effect are the space width between patterns, the aspect ratio, the contact angle of the D.I water rinse and the surface tension of rinse solution. Among these parameters the surface tension of rinse solution can be controlled by us. On the other hand, we've already reported that the penetration of TMAH and D.I water into the resist plays an important role on the lithographic latitude. For example, when we use the resist which TMA ion can be easily diffuse into, D.I water and TMA ion which are penetrated in the resist decreases the aggregation force of resist pattern and causes the pattern collapse even by the weak force against resist pattern. These results indicate that the swelling of photoresist by TMA ion and water is very important factor for controlling the pattern collapse. Currently, two methods are mainly tried to reduce the surface tension of rinse solution: SCF (Super Critical Fluid) and addition of additive to D.I water rinse. We used the latter method this time, because this technique has retrofittability and not special tool. And in this evaluation, we found that the degree of suppressing pattern collapse depends on the additive chemistry or formulation. With consideration given to process factors such as above, we investigated what factors contribute to suppressing pattern collapse

  17. Atmospheric radiation model for water surfaces

    NASA Technical Reports Server (NTRS)

    Turner, R. E.; Gaskill, D. W.; Lierzer, J. R.

    1982-01-01

    An atmospheric correction model was extended to account for various atmospheric radiation components in remotely sensed data. Components such as the atmospheric path radiance which results from singly scattered sky radiation specularly reflected by the water surface are considered. A component which is referred to as the virtual Sun path radiance, i.e. the singly scattered path radiance which results from the solar radiation which is specularly reflected by the water surface is also considered. These atmospheric radiation components are coded into a computer program for the analysis of multispectral remote sensor data over the Great Lakes of the United States. The user must know certain parameters, such as the visibility or spectral optical thickness of the atmosphere and the geometry of the sensor with respect to the Sun and the target elements under investigation.

  18. Morphology and optical properties of aluminum oxide formed into oxalic electrolyte with addition surface active agents

    NASA Astrophysics Data System (ADS)

    Kazarkin, B.; Stsiapanau, A.; Zhilinski, V.; Chernik, A.; Bezborodov, V.; Kozak, G.; Danilovich, S.; Smirnov, A.

    2016-08-01

    The article discusses the results of investigations of porous films of alumina, formed into oxalic electrolyte with addition surface active agents, in particular, ordering structure, roughness of a surface, the optical transparency of the electrolyte concentration and surface active agents. Also discusses the features of the formation of porous films of temperature and IR radiation.

  19. Radon in surface water on Jersey.

    PubMed

    Grainger, C R

    1996-08-01

    A survey of surface water was undertaken, in Jersey, in 1994, to measure the concentration of radon. Over most of the island the levels were found to be low. The highest levels correlated with the areas where granite was intruded into older rocks. The levels found could lead to elevated concentrations in some dwellings but it was felt that radon was not a major risk to the health of the public.

  20. Source Water Assessment for the Las Vegas Valley Surface Waters

    NASA Astrophysics Data System (ADS)

    Albuquerque, S. P.; Piechota, T. C.

    2003-12-01

    The 1996 amendment to the Safe Drinking Water Act of 1974 created the Source Water Assessment Program (SWAP) with an objective to evaluate potential sources of contamination to drinking water intakes. The development of a Source Water Assessment Plan for Las Vegas Valley surface water runoff into Lake Mead is important since it will guide future work on source water protection of the main source of water. The first step was the identification of the watershed boundary and source water protection area. Two protection zones were delineated. Zone A extends 500 ft around water bodies, and Zone B extends 3000 ft from the boundaries of Zone A. These Zones extend upstream to the limits of dry weather flows in the storm channels within the Las Vegas Valley. After the protection areas were identified, the potential sources of contamination in the protection area were inventoried. Field work was conducted to identify possible sources of contamination. A GIS coverage obtained from local data sources was used to identify the septic tank locations. Finally, the National Pollutant Discharge Elimination System (NPDES) Permits were obtained from the State of Nevada, and included in the inventory. After the inventory was completed, a level of risk was assigned to each potential contaminating activity (PCA). The contaminants of concern were grouped into five categories: volatile organic compounds (VOCs), synthetic organic compounds (SOCs), inorganic compounds (IOCs), microbiological, and radionuclides. The vulnerability of the water intake to each of the PCAs was assigned based on these five categories, and also on three other factors: the physical barrier effectiveness, the risk potential, and the time of travel. The vulnerability analysis shows that the PCAs with the highest vulnerability rating include septic systems, golf courses/parks, storm channels, gas stations, auto repair shops, construction, and the wastewater treatment plant discharges. Based on the current water quality

  1. Water quality analysis of surface water: a Web approach.

    PubMed

    Prasad, Poonam; Chaurasia, Meenal; Sohony, R A; Gupta, Indrani; Kumar, R

    2013-07-01

    The chemical, physical and biological characteristics of water with respect to its suitability describe its quality. Concentration of pesticides or fertilisers degrades the water quality and affects marine life. A comprehensive environmental data information system helps to perform and complete common tasks in less time with less effort for data verification, data calculations, graph generation, and proper monitoring, which helps in the further mitigation step. In this paper, focus is given to a web-based system developed to express the quality of water in the imprecise environment of monitoring data. Water samples were analyzed for eight different surface water parameters, in which four parameters such as pH, dissolved oxygen, biochemical oxygen demand, and fecal coliform were used for the water quality index calculation following MPCB Water Quality Standards of class A-II for best designated use. The analysis showed that river points in a particular year were in very bad category with certainty level of 0-38% which is unsuitable for drinking purposes; samples in bad category had certainty level that ranged from 38 to 50%; samples in medium to good category had certainty levels from 50 to 100%, and the remaining samples were in good to excellent category, suitable for drinking purposes, with certainty levels from 63 to 100%.

  2. Rapid Recovery of Cyanobacterial Pigments in Desiccated Biological Soil Crusts following Addition of Water

    PubMed Central

    Abed, Raeid M. M.; Polerecky, Lubos; Al-Habsi, Amal; Oetjen, Janina; Strous, Marc; de Beer, Dirk

    2014-01-01

    We examined soil surface colour change to green and hydrotaxis following addition of water to biological soil crusts using pigment extraction, hyperspectral imaging, microsensors and 13C labeling experiments coupled to matrix-assisted laser desorption and ionization time of flight-mass spectrometry (MALD-TOF MS). The topsoil colour turned green in less than 5 minutes following water addition. The concentrations of chlorophyll a (Chl a), scytonemin and echinenon rapidly increased in the top <1 mm layer while in the deeper layer, their concentrations remained low. Hyperspectral imaging showed that, in both wet and dehydrated crusts, cyanobacteria formed a layer at a depth of 0.2–0.4 mm and this layer did not move upward after wetting. 13C labeling experiments and MALDI TOF analysis showed that Chl a was already present in the desiccated crusts and de novo synthesis of this molecule started only after 2 days of wetting due to growth of cyanobacteria. Microsensor measurements showed that photosynthetic activity increased concomitantly with the increase of Chl a, and reached a maximum net rate of 92 µmol m−2 h−1 approximately 2 hours after wetting. We conclude that the colour change of soil crusts to green upon water addition was not due to hydrotaxis but rather to the quick recovery and reassembly of pigments. Cyanobacteria in crusts can maintain their photosynthetic apparatus intact even under prolonged periods of desiccation with the ability to resume their photosynthetic activities within minutes after wetting. PMID:25375172

  3. Optical Triangulation on Instationary Water Surfaces

    NASA Astrophysics Data System (ADS)

    Mulsow, C.; Maas, H.-G.; Hentschel, B.

    2016-06-01

    The measurement of water surfaces is a key task in the field of experimental hydromechanics. Established techniques are usually gauge-based and often come with a large instrumental effort and a limited spatial resolution. The paper shows a photogrammetric alternative based on the well-known laser light sheet projection technique. While the original approach is limited to surfaces with diffuse reflection properties, the developed technique is capable of measuring dynamically on reflecting instationary surfaces. Contrary to the traditional way, the laser line is not observed on the object. Instead, using the properties of water, the laser light is reflected on to a set of staggered vertical planes. The resulting laser line is observed by a camera and measured by subpixel operators. A calibration based on known still water levels provides the parameters for the translation of image space measurements into water level and gradient determination in dynamic experiments. As a side-effect of the principle of measuring the reflected laser line rather than the projected one, the accuracy can be improved by almost a factor two. In experiments a standard deviation of 0.03 mm for water level changes could be achieved. The measuring rate corresponds to the frame rate of the camera. A complete measuring system is currently under development for the Federal Waterways Engineering and Research Institute (BAW). This article shows the basic principle, potential and limitations of the method. Furthermore, several system variants optimised for different requirements are presented. Besides the geometrical models of different levels of complexity, system calibration procedures are described too. The applicability of the techniques and their accuracy potential are shown in several practical tests.

  4. Microcystins in potable surface waters: toxic effects and removal strategies.

    PubMed

    Roegner, Amber F; Brena, Beatriz; González-Sapienza, Gualberto; Puschner, Birgit

    2014-05-01

    In freshwater, harmful cyanobacterial blooms threaten to increase with global climate change and eutrophication of surface waters. In addition to the burden and necessity of removal of algal material during water treatment processes, bloom-forming cyanobacteria can produce a class of remarkably stable toxins, microcystins, difficult to remove from drinking water sources. A number of animal intoxications over the past 20 years have served as sentinels for widespread risk presented by microcystins. Cyanobacterial blooms have the potential to threaten severely both public health and the regional economy of affected communities, particularly those with limited infrastructure or resources. Our main objectives were to assess whether existing water treatment infrastructure provides sufficient protection against microcystin exposure, identify available options feasible to implement in resource-limited communities in bloom scenarios and to identify strategies for improved solutions. Finally, interventions at the watershed level aimed at bloom prevention and risk reduction for entry into potable water sources were outlined. We evaluated primary studies, reviews and reports for treatment options for microcystins in surface waters, potable water sources and treatment plants. Because of the difficulty of removal of microcystins, prevention is ideal; once in the public water supply, the coarse removal of cyanobacterial cells combined with secondary carbon filtration of dissolved toxins currently provides the greatest potential for protection of public health. Options for point of use filtration must be optimized to provide affordable and adequate protection for affected communities. PMID:24038121

  5. Increasing iron concentrations in surface waters - a factor behind brownification?

    NASA Astrophysics Data System (ADS)

    Kritzberg, E. S.; Ekström, S. M.

    2012-04-01

    Browning of inland waters has been noted over large parts of the Northern hemisphere and is a phenomenon with both ecological and societal consequences. The increase in water color is generally ascribed to increasing concentrations of dissolved organic matter of terrestrial origin. However, oftentimes the increase in water color is larger than that of organic matter, implying that changes in the concentration of organic matter alone cannot explain the enhanced water color. Water color is known to be affected also by the quality of organic matter and the prevalence of iron. Here we investigated trends in water color, organic matter and iron between 1972 and 2010 in 30 rivers draining into the Swedish coast (data from the national Swedish monitoring program), and performed a laboratory iron addition experiment to natural waters, to evaluate the role of iron and organic matter in determining water color. By comparing the effect of iron additions on water color in the experiment, to variation in water color and iron concentration in the monitoring data, we show that iron can explain a significant share of the variation in water color (on average 25 %), especially in the rivers in the north of Sweden (up to 74 %). Furthermore, positive trends for iron are seen in 27 of 30 rivers (21-468 %) and the increase in iron is larger than that of organic matter, indicating that iron and organic matter concentrations are controlled by similar but not identical processes. We speculate that increasing iron concentrations can be caused by changes in redox conditions, that mean that more anoxic water with high concentrations of soluble FeII are feeding into the surface waters. More studies are needed about why iron is increasing so strongly, since both causes and consequences are partly different from those of increasing organic matter content.

  6. Increasing iron concentrations in surface waters - a factor behind brownification?

    NASA Astrophysics Data System (ADS)

    Kritzberg, E. S.; Ekström, S. M.

    2011-12-01

    Browning of inland waters has been noted over large parts of the Northern Hemisphere and is a phenomenon with both ecological and societal consequences. The increase in water color is generally ascribed to increasing amounts of dissolved organic matter of terrestrial origin. However, oftentimes the increase in water color is larger than that of organic matter, implying that changes in the amount of organic matter alone cannot explain the enhanced water color. Water color is known to be affected also by the quality of organic matter and the prevalence of iron. Here we investigated trends in water color, organic matter and iron between 1972 and 2010 in 30 rivers draining into the Swedish cost, and peformed a laboratory iron addition experiment to natural waters, to evaluate the role of iron and organic matter in determining water color. By comparing the effect of iron additions on water color in the experiment, to variation in water color and iron concentration in the monitoring data, we show that iron can explain a significant share of the variation in water color (on average 25%), especially in the rivers in the north of Sweden (up to 74%). Further more, positive trends for iron are seen in 27 of 30 rivers (21-468%) and the increase in iron is larger than that of organic matter, indicating that iron and organic matter concentrations are controlled by similar but not identical processes. We speculate that increasing iron concentrations can be caused by changes in redox conditions, that mean that more anoxic water with high concentrations of soluble FeII are feeding into the surface waters. More studies are needed about why iron is increasing so strongly, since both causes and consequences are partly different from those of increasing organic matter content.

  7. How Water Advances on Superhydrophobic Surfaces

    NASA Astrophysics Data System (ADS)

    Schellenberger, Frank; Encinas, Noemí; Vollmer, Doris; Butt, Hans-Jürgen

    2016-03-01

    Superliquid repellency can be achieved by nano- and microstructuring surfaces in such a way that protrusions entrap air underneath the liquid. It is still not known how the three-phase contact line advances on such structured surfaces. In contrast to a smooth surface, where the contact line can advance continuously, on a superliquid-repellent surface, the contact line has to overcome an air gap between protrusions. Here, we apply laser scanning confocal microscopy to get the first microscopic videos of water drops advancing on a superhydrophobic array of micropillars. In contrast to common belief, the liquid surface gradually bends down until it touches the top face of the next micropillars. The apparent advancing contact angle is 180°. On the receding side, pinning to the top faces of the micropillars determines the apparent receding contact angle. Based on these observations, we propose that the apparent receding contact angle should be used for characterizing superliquid-repellent surfaces rather than the apparent advancing contact angle and hysteresis.

  8. Versatile antifouling polyethersulfone filtration membranes modified via surface grafting of zwitterionic polymers from a reactive amphiphilic copolymer additive.

    PubMed

    Zhao, Yi-Fan; Zhang, Pei-Bin; Sun, Jian; Liu, Cui-Jing; Yi, Zhuan; Zhu, Li-Ping; Xu, You-Yi

    2015-06-15

    Here we describe the development of versatile antifouling polyethersulfone (PES) filtration membranes modified via surface grafting of zwitterionic polymers from a reactive amphiphilic copolymer additive. Amphiphilic polyethersulfone-block-poly(2-hydroxyethyl methacrylate) (PES-b-PHEMA) was beforehand designed and used as the blending additive of PES membranes prepared by phase inversion technique. The surface enriched PHEMA blocks on membrane surface acted as an anchor to immobilize the initiating site. Poly(sulfobetaine methacrylate) (PSBMA) were subsequently grafted onto the PES blend membranes by surface-initiated atom transfer radical polymerization (SI-ATRP). The analysis of surface chemistry confirmed the successful grafting of zwitterionic PSBMA brushes on PES membrane surface. The resulted PES-g-PSBMA membranes were capable of separating proteins from protein solution and oil from oil/water emulsion efficiently. Furthermore, the modified membranes showed high hydrophilicity and strongly antifouling properties due to the incorporation of well-defined PSBMA layer. In addition, the PES-g-PSBMA membranes exhibited excellent blood compatibility and durability during the washing process. The developed antifouling PES membranes are versatile and can find their applications in protein filtration, blood purification and oil/water separation, etc. PMID:25752579

  9. Removal of perfluorooctanoate from surface water by polyaluminium chloride coagulation.

    PubMed

    Deng, Shubo; Zhou, Qin; Yu, Gang; Huang, Jun; Fan, Qing

    2011-02-01

    Perfluorooctanoate (PFOA) has been detected in surface water all over the world, and little is known of its removal by coagulation in water treatment plants. In this study, polyaluminium chloride (PACl) was used to remove PFOA from surface water, and the effects of coagulant dose, solution pH, temperature, and initial turbidity on the removal of both PFOA and suspended solids (SS) from water were investigated. Since the SS had high sorption affinity for PFOA, most PFOA was adsorbed on the particles and removed via the SS removal in the coagulation process. PFOA concentrations in aqueous phase decreased with increasing initial turbidity and PACl dose, while they increased with increasing solution pH and temperature. Other perfluorinated compounds (PFCs) with different C-F chain lengths and functional groups were also compared with PFOA. It was proved that hydrophobic interaction played an important role in the adsorption of PFOA on the SS. The addition of powdered activated carbon (PAC) before the coagulation process significantly enhanced the removal efficiency of PFOA in water, and the residual PFOA concentrations in water were less than 1 μg/L after the addition of 1-16 mg/L PAC and subsequent coagulation when the initial PFOA concentrations were in the range of 0.5-3 mg/L. PMID:21163511

  10. Assessing nitrogen pressures on European surface water

    NASA Astrophysics Data System (ADS)

    Grizzetti, B.; Bouraoui, F.; de Marsily, G.

    2008-12-01

    The European environmental legislation on water, in particular the 2000 Water Framework Directive, requires the evaluation of nutrient pressures and the assessment of mitigation measures at the river basin scale. Models have been identified as tools that can contribute to fulfill these requirements. The objective of this research was the implementation of a modeling approach (Geospatial Regression Equation for European Nutrient losses (GREEN)) to assess the actual nitrogen pressures on surface water quality at medium and large basin scale (European scale) using readily available data. In particular the aim was to estimate diffuse nitrogen emissions into surface waters, contributions by different sources (point and diffuse) to the nitrate load in rivers, and nitrogen retention in river systems. A comprehensive database including nutrient sources and physical watershed characteristics was built at the European scale. The modeling partially or entirely covered some of the larger and more populated European river basins, including the Danube, Rhine, Elbe, Weser, and Ems in Germany, the Seine and Rhone in France, and the Meuse basin shared by France and Belgium. The model calibration was satisfactory for all basins. The source contribution to the in-stream nitrogen load, together with the diffuse nitrogen emissions and river nitrogen retention were estimated and were found to be in the range of values reported in the literature. Finally, the model results were extrapolated to estimate the diffuse nitrogen emission and source apportionment at the European scale.

  11. Quality of Surface Water in Missouri, Water Year 2007

    USGS Publications Warehouse

    Otero-Benitez, William; Davis, Jerri V.

    2009-01-01

    The U.S. Geological Survey, in cooperation with the Missouri Department of Natural Resources, designed and operates a series of monitoring stations on streams throughout Missouri known as the Ambient Water-Quality Monitoring Network. During the 2007 water year (October 1, 2006 through September 30, 2007), data were collected at 67 stations including two U.S. Geological Survey National Stream Quality Accounting Network stations and one spring sampled in cooperation with the U.S. Forest Service. Dissolved oxygen, specific conductance, water temperature, suspended solids, suspended sediment, fecal coliform bacteria, dissolved nitrite plus nitrte, total phosphorus, dissolved and total recoverable lead and zinc, and selected pesticide data summaries are presented for 64 of these stations, which primarily have been classified in groups corresponding to the physiography of the State, main land use, or unique station types. In addition, a summary of hydrologic conditions in the State during water year 2007 is presented.

  12. Dendrite-Free Li Deposition Using Trace-Amounts of Water as an Electrolyte Additive

    SciTech Connect

    Qian, Jiangfeng; Xu, Wu; Bhattacharya, Priyanka; Engelhard, Mark H.; Henderson, Wesley A.; Zhang, Yaohui; Zhang, Jiguang

    2015-07-01

    Residual water presents in nonaqueous electrolytes has been widely regarded as a detrimental factor for lithium (Li) batteries. This is because water is highly reactive with the commonly used LiPF6 salt and leads to the formation of HF that corrodes battery materials. In this work, we demonstrate that a controlled trace-amount of water (25-100 ppm) can be an effective electrolyte additive for achieving dendrite-free Li metal deposition in LiPF6-based electrolytes and avoid its detrimental effect at the same time. Detailed analyses reveal that the trace amount of HF formed by the decomposition reaction of LiPF6 with water will be electrochemically reduced during initial Li deposition process to form a uniform and dense LiF-rich SEI layer on the surface of the substrate. This LiF-rich SEI layer leads to a uniform distribution of the electric field on the substrate surface and enables uniform and dendrite-free Li deposition. Meanwhile the detrimental effect of HF is diminished due to the consumption of HF in the LiF formation process. Microscopic analysis reveals that the as-deposited dendrite-free Li films exhibit a self-aligned and highly-compacted Li nanorods structure which is consistent with their charming blue color or known as structure color. These findings clearly demonstrate a novel approach to control the nucleation and grow process of Li metal films using well-controlled trace-amount of water. They also shine the light on the effect of water on other electrodeposition processes.

  13. Lawrence Livermore National Laboratory Surface Water Protection: A Watershed Approach

    SciTech Connect

    Coty, J

    2009-03-16

    This surface water protection plan (plan) provides an overview of the management efforts implemented at Lawrence Livermore National Laboratory (LLNL) that support a watershed approach to protect surface water. This plan fulfills a requirement in the Department of Energy (DOE) Order 450.1A to demonstrate a watershed approach for surface water protection that protects the environment and public health. This plan describes the use of a watershed approach within which the Laboratory's current surface water management and protections efforts have been structured and coordinated. With more than 800 million acres of land in the U.S. under federal management and stewardship, a unified approach across agencies provides enhanced resource protection and cost-effectiveness. The DOE adopted, along with other federal agencies, the Unified Federal Policy for a Watershed Approach to Federal Land and Resource Management (UFP) with a goal to protect water quality and aquatic ecosystems on federal lands. This policy intends to prevent and/or reduce water pollution from federal activities while fostering a cost-effective watershed approach to federal land and resource management. The UFP also intends to enhance the implementation of existing laws (e.g., the Clean Water Act [CWA] and National Environmental Policy Act [NEPA]) and regulations. In addition, this provides an opportunity for the federal government to serve as a model for water quality stewardship using a watershed approach for federal land and resource activities that potentially impact surface water and its uses. As a federal land manager, the Laboratory is responsible for a small but important part of those 800 million acres of land. Diverse land uses are required to support the Laboratory's mission and provide an appropriate work environment for its staff. The Laboratory comprises two sites: its main site in Livermore, California, and the Experimental Test Site (Site 300), near Tracy, California. The main site is largely

  14. Water resources data for Maryland, Delaware, and Washington, D.C, water year 2002, Volume 1. surface-water data

    USGS Publications Warehouse

    James, Robert W.; Saffer, Richard W.; Pentz, Robert H.; Tallman, Anthony J.

    2003-01-01

    Water resources data for the 2002 water year for Maryland, Delaware, and Washington, D.C. consist of records of stage, discharge, and water quality of streams; stage and contents of lakes and reservoirs. This volume (Volume 1. Surface-Water Data) contains records for water discharge at 137 gaging stations; stage and contents of 1 reservoir; and water quality at 28 gaging stations. Also included are stage and discharge for 3 crest-stage partial-record stations and stage only for 8 tidal crest-stage partialrecord stations. Additional water data were collected at various sites not involved in the systematic data-collection program and are published as miscellaneous measurements. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State, local, and Federal agencies in Maryland, Delaware, and Washington, D.C.

  15. Water resources data for Maryland, Delaware, and Washington, D.C, water year 2003, volume 1. surface-water data

    USGS Publications Warehouse

    James, Robert W.; Saffer, Richard W.; Pentz, Robert H.; Tallman, Anthony J.

    2003-01-01

    Water resources data for the 2003 water year for Maryland, Delaware, and Washington, D.C. consist of records of stage, discharge, and water quality of streams; stage and contents of lakes and reservoirs. This volume (Volume 1. Surface-Water Data) contains records for water discharge at 140 gaging stations; stage and contents of 1 reservoir; and water quality at 17 gaging stations. Also included are stage and discharge for 3 crest-stage partial-record stations and stage only for 10 tidal crest-stage partial-record stations. Additional water data were collected at various sites not involved in the systematic data-collection program and are published as miscellaneous measurements. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State, local, and Federal agencies in Maryland, Delaware, and Washington, D.C.

  16. Water resources data, Maryland, Delaware, and Washington, D.C., water year 2000, volume 1. surface-water data

    USGS Publications Warehouse

    James, Robert W.; Saffer, Richard W.; Tallman, Anthony J.

    2001-01-01

    Water resources data for the 2000 water year for Maryland and Delaware consist of records of stage, discharge, and water quality of streams; stage and contents of lakes and reservoirs. This volume (Volume 1. Surface-Water Data) contains records for water discharge at 121 gaging stations; stage and contents of 1 reservoir; and water quality at 21 gaging stations. Also included are stage and discharge for 3 creststage partial-record stations, discharge only for 27 low-flow partial-record stations, and stage only for 5 tidal crest-stage partial-record stations. Additional water data were collected at various sites not involved in the systematic data-collection program and are published as miscellaneous measurements. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State, local, and Federal agencies in Maryland and Delaware.

  17. Water resources data Maryland, Delaware, and Washington, D.C.,water year 2005, Volume 1. Surface-water data

    USGS Publications Warehouse

    Saffer, Richard W.; Pentz, Robert H.; Tallman, Anthony J.

    2006-01-01

    Water resources data for the 2005 water year for Maryland, Delaware, and Washington, D.C. consist of records of stage, discharge, and water quality of streams; stage and contents of lakes and reservoirs. This volume (Volume 1. Surface-Water Data) contains records for water discharge at 145 gaging stations; stage and contents of 1 reservoir; stage only for 2 tidal gaging station; and water quality at 19 gaging stations. Also included are stage only for 11 tidal crest-stage partial-record stations. Additional water data were collected at various sites not involved in the systematic data-collection program and are published as miscellaneous measurements. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State, local, and Federal agencies in Maryland, Delaware, and Washington, D.C.

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

    PubMed

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

    2016-09-01

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

  19. Effects of Surface Modification Conditions on Hydrophobicity of Silica-based Coating Additives

    SciTech Connect

    Armstrong, Beth L; Pawel, Steven J; Hunter, Scott Robert; Haynes, James A; Hillesheim, Daniel A

    2013-01-01

    Superhydrophobic silica (SHS) powders are being evaluated as a potential additive to the polyurethane topcoats used in Chemical Agent Resistant Coating (CARC) systems, with the goal of improving water repellency and corrosion protection characteristics. The current generation of CARC topcoats is already highly loaded with solids, and thus there is a premium on minimization of the total SHS powder required to achieve the desired properties. Therefore, efficient surface modification of the silica and proper dispersion in the coating will be required. The effect of a dispersant on the surface modification of silica particles by chlorosilanes was addressed in this study. The properties of various SHS powders were characterized by thermogravimetric analysis and mass spectroscopy. Correlations between powder modification conditions and the ultimate effects of the modified particles on hydrophobicity of CARC topcoats were assessed. The use of contact and rolling angle measurements along with scanning electron microscopy are discussed as they pertain to the ability to quantify the effects of modified silicas on corrosion prevention coatings. Furthermore, a systematic approach to modifying and testing both powders and top coats of corrosion prevention systems is presented.

  20. Field Techniques for Estimating Water Fluxes Between Surface Water and Ground Water

    USGS Publications Warehouse

    Rosenberry, Donald O.; LaBaugh, James W.

    2008-01-01

    This report focuses on measuring the flow of water across the interface between surface water and ground water, rather than the hydrogeological or geochemical processes that occur at or near this interface. The methods, however, that use hydrogeological and geochemical evidence to quantify water fluxes are described herein. This material is presented as a guide for those who have to examine the interaction of surface water and ground water. The intent here is that both the overview of the many available methods and the in-depth presentation of specific methods will enable the reader to choose those study approaches that will best meet the requirements of the environments and processes they are investigating, as well as to recognize the merits of using more than one approach. This report is designed to make the reader aware of the breadth of approaches available for the study of the exchange between surface and ground water. To accomplish this, the report is divided into four chapters. Chapter 1 describes many well-documented approaches for defining the flow between surface and ground waters. Subsequent chapters provide an in-depth presentation of particular methods. Chapter 2 focuses on three of the most commonly used methods to either calculate or directly measure flow of water between surface-water bodies and the ground-water domain: (1) measurement of water levels in well networks in combination with measurement of water level in nearby surface water to determine water-level gradients and flow; (2) use of portable piezometers (wells) or hydraulic potentiomanometers to measure hydraulic gradients; and (3) use of seepage meters to measure flow directly. Chapter 3 focuses on describing the techniques involved in conducting water-tracer tests using fluorescent dyes, a method commonly used in the hydrogeologic investigation and characterization of karst aquifers, and in the study of water fluxes in karst terranes. Chapter 4 focuses on heat as a tracer in hydrological

  1. Chemical composition of Texas surface waters, 1949

    USGS Publications Warehouse

    Irelan, Burdge

    1950-01-01

    This report is the fifth the a series of publications by the Texas Board of Water Engineers giving chemical analyses of the surface waters in the State of Texas. The samples for which data are given were collected between October 1, 1948 and September 30, 1949. During the water year 25 daily sampling stations were maintained by the Geological Survey. Sampled were collected less frequently during the year at many other points. Quality of water records for previous years can be found in the following reports: "Chemical Composition of Texas Surface Waters, 1938-1945," by W. W. Hastings, and J. H. Rowley; "Chemical Composition of Texas Surface Waters, 1946," by W. W. Hastings and B. Irelan; "Chemical Composition of Texas Surface Waters, 1947," by B. Irelan and J. R. Avrett; "Chemical Composition of Texas Surface Waters, 1948," by B. Irelan, D. E. Weaver, and J. R. Avrett. These reports may be obtained from the Texas Board of Water Engineers and Geological Survey at Austin, Texas. Samples for chemical analysis were collected daily at or near points on streams where gaging stations are maintained for measurement of discharge. Most of the analyses were made of 10-day composites of daily samples collected for a year at each sampling point. Three composite samples were usually prepared each month by mixing together equal quantities of daily samples collected for the 1st to the 10th, from the 11th to the 20th, and during the remainder of the month. Monthly composites were made at a few stations where variation in daily conductance was small. For some streams that are subject to sudden large changes in chemical composition, composite samples were made for shorter periods on the basis of the concentration of dissolved solids as indicated by measurement of specific conductance of the daily samples. The mean discharge for the composite period is reported in second-feet. Specific conductance values are expressed as "micromhos, K x 10 at 25° C." Silica, calcium, magnesium, sodium

  2. Evaluation of the EHL Film Thickness and Extreme Pressure Additives on Gear Surface Fatigue Life

    NASA Technical Reports Server (NTRS)

    Townsend, Dennis P.; Shimski, John

    1994-01-01

    Surface pitting fatigue life tests were conducted with seven lubricants, using AISI 9310 spur gears. The test lubricants can be classified as synthetic polyol-esters with various viscosities and additive packages. The lubricant with a viscosity that provided a specific film thickness greater than one and with an additive package produced gear surface fatigue lives that were 8.6 times that for lubricants with a viscosity that provided specific film thickness less than one. Lubricants with the same viscosity and similar additive packages gave equivalent gear surface fatigue lives.

  3. Effect of Organic Additive on Surface Roughness of Polycrystalline Silicon Film after Chemical Mechanical Polishing

    NASA Astrophysics Data System (ADS)

    Hwang, Hee-Sub; Park, Jin-Hyung; Yi, Sok-Ho; Paik, Ungyu; Park, Jea-Gun

    2010-01-01

    The effect of an organic additive on the surface roughness of a polycrystalline silicon (poly-Si) film was investigated by chemical mechanical polishing (CMP). The surface roughness of the polished poly-Si film was markedly reduced by adding 0.001 wt % hydroxyl ethyl cellulose (HEC) and then decreased slightly with further addition of HEC. We concluded that the reduction of surface roughness was attributed to the formation of a hydroplane layer on the poly-Si surface. Evidence of the hydroplane layer was verified by contact angle and X-ray photoelectron spectroscopy (XPS) measurements.

  4. Acidic deposition and surface water chemistry

    NASA Astrophysics Data System (ADS)

    Church, M. R.

    A pair of back-to-back (morning and afternoon) hydrology sessions, held December 10, 1987, at the AGU Fall Meeting in San Francisco, Calif., covered “Predicting the Effects of Acidic Deposition on Surface Water Chemistry.” The combined sessions included four invited papers, 12 contributed papers, and a panel discussion at its conclusion. The gathering dealt with questions on a variety of aspects of modeling the effects of acidic deposition on surface water chemistry.Contributed papers included discussions on the representation of processes in models as well as limiting assumptions in model application (V. S. Tripathi et al., Oak Ridge National Laboratory, Oak Ridge, Tenn., and E. C. Krug, Illinois State Water Survey, Champaign), along with problems in estimating depositional inputs to catchments and thus inputs to be used in the simulation of catchment response (M. M. Reddy et al., U.S. Geological Survey, Lakewood, Colo.; and E. A. McBean, University of Waterloo, Waterloo, Canada). L. A. Baker et al. (University of Minnesota, Minneapolis) dealt with the problem of modeling seepage lake systems, an exceedingly important portion of the aquatic resources in Florida and parts of the upper U.S. Midwest. J. A. Hau and Y. Eckstein (Kent State University, Kent, Ohio) considered equilibrium modeling of two northern Ohio watersheds that receive very different loads of acidic deposition but are highly similar in other respects.

  5. Phospholipid surface bilayers at the air-water interface. II. Water permeability of dimyristoylphosphatidylcholine surface bilayers.

    PubMed Central

    Ginsberg, L; Gershfeld, N L

    1985-01-01

    Dispersions of dimyristoylphosphatidylcholine (DMPC) in water have been reported to form a structure at 29 degrees C at the equilibrium air/water surface with a molecular density equal to that of a typical bilayer. In this study, the water permeability of this structure has been evaluated by measuring the rate of water evaporation from DMPC dispersions in water in the temperature range where the surface film density exceeds that of a monolayer. Evaporation rates for the lipid dispersions did not deviate from those for lipid-free systems throughout the entire temperature range examined (20-35 degrees C) except at 29 degrees C, where a barrier to evaporation was detected. This strengthens the view that the structure that forms at this temperature has the properties of a typical bilayer. PMID:3978199

  6. Capillary condensation of water between mica surfaces above and below zero-effect of surface ions.

    PubMed

    Nowak, Dominika; Christenson, Hugo K

    2009-09-01

    We have studied the capillary condensation of water from saturated vapor below 0 degrees C in the annular wedge-pore formed around two mica surfaces in contact in a surface force apparatus. The condensed water remains liquid down to at least -9 degrees C, and the measured condensate size is close to the predictions of a recent model for the dependence of the interfacial curvature of supercooled capillary condensates on temperature and surface tension. The small deviation observed may be accounted for by assuming that solute as K(2)CO(3) from the mica-condensate interface dissolves in the condensates and gives rise to an additional depression of the freezing point apart from that caused by the interface curvature. By contrast, measurements of the interface curvature at relative vapor pressures of 0.95-0.99 at 20 degrees C confirm a significantly larger deviation from the Kelvin equation. The magnitude of the deviation is in remarkable agreement with that calculated from the results of an earlier study of capillary condensation of water from a nonpolar liquid, also at T = 20 degrees C. Evidently, additional solute from the surrounding mica surface migrates into the condensates at room temperature. We conclude that the surface diffusion of ions on mica is much slower at subzero temperatures than at room temperature. PMID:19705887

  7. Water and Carbon Dioxide Adsorption at Olivine Surfaces

    SciTech Connect

    Kerisit, Sebastien N.; Bylaska, Eric J.; Felmy, Andrew R.

    2013-11-14

    Plane-wave density functional theory (DFT) calculations were performed to simulate water and carbon dioxide adsorption at the (010) surface of five olivine minerals, namely, forsterite (Mg2SiO4), calcio-olivine (Ca2SiO4), tephroite (Mn2SiO4), fayalite (Fe2SiO4), and Co-olivine (Co2SiO4). Adsorption energies per water molecule obtained from energy minimizations varied from -78 kJ mol-1 for fayalite to -128 kJ mol-1 for calcio-olivine at sub-monolayer coverage and became less exothermic as coverage increased. In contrast, carbon dioxide adsorption energies at sub-monolayer coverage ranged from -20 kJ mol-1 for fayalite to -59 kJ mol-1 for calcio-olivine. Therefore, the DFT calculations show a strong driving force for carbon dioxide displacement by water at the surface of all olivine minerals in a competitive adsorption scenario. Additionally, adsorption energies for both water and carbon dioxide were found to be more exothermic for the alkaline-earth (AE) olivines than for the transition-metal (TM) olivines and to not correlate with the solvation enthalpies of the corresponding divalent cations. However, a correlation was obtained with the charge of the surface divalent cation indicating that the more ionic character of the AE cations in the olivine structure relative to the TM cations leads to greater interactions with adsorbed water and carbon dioxide molecules at the surface and thus more exothermic adsorption energies for the AE olivines. For calcio-olivine, which exhibits the highest divalent cation charge of the five olivines, ab initio molecular dynamics simulations showed that this effect leads both water and carbon dioxide to react with the surface and form hydroxyl groups and a carbonate-like species, respectively.

  8. Effect of Periodic Water Addition on Citric Acid Production in Solid State Fermentation

    NASA Astrophysics Data System (ADS)

    Utpat, Shraddha S.; Kinnige, Pallavi T.; Dhamole, Pradip B.

    2013-09-01

    Water addition is one of the methods used to control the moisture loss in solid state fermentation (SSF). However, none of the studies report the timing of water addition and amount of water to be added in SSF. Therefore, this work was undertaken with an objective to evaluate the performance of periodic water addition on citric acid production in SSF. Experiments were conducted at different moistures (50-80 %) and temperatures (30-40 °C) to simulate the conditions in a fermenter. Citric acid production by Aspergillus niger (ATCC 9029) using sugarcane baggase was chosen as a model system. Based on the moisture profile, citric acid and sugar data, a strategy was designed for periodic addition of water. Water addition at 48, 96, 144 and 192 h enhanced the citric acid production by 62 % whereas water addition at 72, 120, and 168 h increased the citric acid production by just 17 %.

  9. Surface crystallization of supercooled water in clouds.

    PubMed

    Tabazadeh, A; Djikaev, Y S; Reiss, H

    2002-12-10

    The process by which liquid cloud droplets homogeneously crystallize into ice is still not well understood. The ice nucleation process based on the standard and classical theory of homogeneous freezing initiates within the interior volume of a cloud droplet. Current experimental data on homogeneous freezing rates of ice in droplets of supercooled water, both in air and emulsion oil samples, show considerable scatter. For example, at -33 degrees C, the reported volume-based freezing rates of ice in supercooled water vary by as many as 5 orders of magnitude, which is well outside the range of measurement uncertainties. Here, we show that the process of ice nucleus formation at the air (or oil)-liquid water interface may help to explain why experimental results on ice nucleation rates yield different results in different ambient phases. Our results also suggest that surface crystallization of ice in cloud droplets can explain why low amounts of supercooled water have been observed in the atmosphere near -40 degrees C.

  10. Quality of surface water in Missouri, water year 2013

    USGS Publications Warehouse

    Barr, Miya N.; Schneider, Rachel E.

    2014-01-01

    The U.S. Geological Survey, in cooperation with the Missouri Department of Natural Resources, designed and operates a series of monitoring stations on streams and springs throughout Missouri known as the Ambient Water-Quality Monitoring Network. During the 2013 water year (October 1, 2012, through September 30, 2013), data were collected at 79 stations—73 Ambient Water-Quality Monitoring Network stations, 4 alternate Ambient Water-Quality Monitoring Network stations, and 2 U.S. Geological Survey National Stream Quality Accounting Network stations. Dissolved oxygen, specific conductance, water temperature, suspended solids, suspended sediment, Escherichia coli bacteria, fecal coliform bacteria, dissolved nitrate plus nitrite as nitrogen, total phosphorus, dissolved and total recoverable lead and zinc, and select pesticide compound summaries are presented for 76 of these stations. The stations primarily have been classified into groups corresponding to the physiography of the State, primary land use, or unique station types. In addition, a summary of hydrologic conditions in the State including peak discharges, monthly mean discharges, and 7-day low flow is presented.

  11. Quality of surface water in Missouri, water year 2012

    USGS Publications Warehouse

    Barr, Miya N.

    2014-01-01

    The U.S. Geological Survey, in cooperation with the Missouri Department of Natural Resources, designed and operates a series of monitoring stations on streams and springs throughout Missouri known as the Ambient Water-Quality Monitoring Network. During the 2012 water year (October 1, 2011, through September 30, 2012), data were collected at 81 stations—73 Ambient Water-Quality Monitoring Network stations, 6 alternate Ambient Water-Quality Monitoring Network stations, and 2 U.S. Geological Survey National Stream Quality Accounting Network stations. Dissolved oxygen, specific conductance, water temperature, suspended solids, suspended sediment, fecal coliform bacteria, Escherichia coli bacteria, dissolved nitrate plus nitrite as nitrogen, total phosphorus, dissolved and total recoverable lead and zinc, and select pesticide compound summaries are presented for 78 of these stations. The stations primarily have been classified into groups corresponding to the physiography of the State, primary land use, or unique station types. In addition, a summary of hydrologic conditions in the State including peak discharges, monthly mean discharges, and 7-day low flow is presented.

  12. The effect of surface charge and KNO 3 additive on the crystallization of potassium chloride

    NASA Astrophysics Data System (ADS)

    Abdullah Ceyhan, Ayhan; Nusret Bulutcu, A.

    2011-07-01

    In this study, crystal growth and dissolution rates of potassium chloride crystals in pure solution and in the presence of potassium nitrate were investigated in a stagnant type single crystal cell using an image analyzer system. Closely sized seed crystals were separated with respect to their surface potentials using an electrostatic separator and then growth and dissolution behavior of potassium chloride crystals having different surface charges were systematically measured in pure solution and at 10, 100 and 1000 ppm additive concentrations at around 20 °C. In high supersaturation levels, very thin but very long rod-like growth, growing perpendicular to the surface, were observed. This is considered to result from surface nucleation. A dead zone was detected and its width was a function of surface potential of seed crystals. It was determined that, potassium nitrate additive, which has a common ion with KCl leads to increase the surface potential but not to affect the growth behavior, significantly.

  13. 75 FR 22589 - Preliminary Listing of an Additional Water to Wisconsin's 2008 List of Waters Under Section 303(d...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-29

    ... AGENCY Preliminary Listing of an Additional Water to Wisconsin's 2008 List of Waters Under Section 303(d) of the Clean Water Act AGENCY: Environmental Protection Agency (EPA). ACTION: Notice and request for comments. SUMMARY: This notice announces the availability of EPA's decision identifying one water...

  14. Single and double addition of oxygen atoms to propyne on surfaces at low temperatures.

    PubMed

    Kimber, Helen J; Ennis, Courtney P; Price, Stephen D

    2014-01-01

    Experiments designed to simulate the low temperature surface chemistry occurring in interstellar clouds provide clear evidence of a reaction between oxygen atoms and propyne ice. The reactants are dosed onto a surface held at a fixed temperature between 14 and 100 K. After the dosing period, temperature programmed desorption (TPD), coupled with time-of-flight mass spectrometry, are used to identify two reaction products with molecular formulae C3H4O and C3H4O2. These products result from the addition of a single oxygen atom, or two oxygen atoms, to a propyne reactant. A simple model has been used to extract kinetic data from the measured yield of the single-addition (C3H4O) product at surface temperatures from 30-100 K. This modelling reveals that the barrier of the solid-state reaction between propyne and a single oxygen atom (160 +/- 10 K) is an order of magnitude less than that reported for the gas-phase reaction. In addition, estimates for the desorption energy of propyne and reaction rate coefficient, as a function of temperature, are determined for the single addition process from the modelling. The yield of the single addition product falls as the surface temperature decreases from 50 K to 30K, but rises again as the surface temperature falls below 30 K. This increase in the rate of reaction at low surface temperatures is indicative of an alternative, perhaps barrierless, pathway to the single addition product which is only important at low surface temperatures. The kinetic model has been further developed to characterize the double addition reaction, which appears to involve the addition of a second oxygen atom to C3H4O. This modelling indicates that this second addition is a barrierless process. The kinetic parameters we extract from our experiments indicate that the reaction between atomic oxygen and propyne could occur under on interstellar dust grains on an astrophysical time scale.

  15. Effects of additives on volume change on melting, surface tension, and viscosity of liquid aluminum oxide

    NASA Technical Reports Server (NTRS)

    Bates, J. L.; Rasmussen, J. J.

    1972-01-01

    The effects of various oxide additives on the volume change on melting, the surface tension, and the viscosity of liquid Al2O3 were studied. Additives of Sm2O3, MgO, and Y2O3 which form solid solutions, compounds, and multiphase solids with Al2O3 were studied. A review of the property data for Al2O3 and Al2O3 containing oxide additives is presented. Oxide additives to Al2O3 reduce the volume change on melting and with the exception of SiO2 lower the viscosity; surface tensions change with oxide additives, but changes vary with different container material. Viscosity and volume change on melting appeared to be significantly more important for studying the properties of liquid oxides than surface tension. Supercooling of 270 K of yttrium aluminum garnet was observed.

  16. Contamination of surface, ground, and drinking water from pharmaceutical production.

    PubMed

    Fick, Jerker; Söderström, Hanna; Lindberg, Richard H; Phan, Chau; Tysklind, Mats; Larsson, D G Joakim

    2009-12-01

    Low levels of pharmaceuticals are detected in surface, ground, and drinking water worldwide. Usage and incorrect disposal have been considered the major environmental sources of these microcontaminants. Recent publications, however, suggest that wastewater from drug production can potentially be a source of much higher concentrations in certain locations. The present study investigated the environmental fate of active pharmaceutical ingredients in a major production area for the global bulk drug market. Water samples were taken from a common effluent treatment plant near Hyderabad, India, which receives process water from approximately 90 bulk drug manufacturers. Surface water was analyzed from the recipient stream and from two lakes that are not contaminated by the treatment plant. Water samples were also taken from wells in six nearby villages. The samples were analyzed for the presence of 12 pharmaceuticals with liquid chromatography-mass spectrometry. All wells were determined to be contaminated with drugs. Ciprofloxacin, enoxacin, cetirizine, terbinafine, and citalopram were detected at more than 1 microg/L in several wells. Very high concentrations of ciprofloxacin (14 mg/L) and cetirizine (2.1 mg/L) were found in the effluent of the treatment plant, together with high concentrations of seven additional pharmaceuticals. Very high concentrations of ciprofloxacin (up to 6.5 mg/L), cetirizine (up to 1.2 mg/L), norfloxacin (up to 0.52 mg/L), and enoxacin (up to 0.16 mg/L) were also detected in the two lakes, which clearly shows that the investigated area has additional environmental sources of insufficiently treated industrial waste. Thus, insufficient wastewater management in one of the world's largest centers for bulk drug production leads to unprecedented drug contamination of surface, ground, and drinking water. This raises serious concerns regarding the development of antibiotic resistance, and it creates a major challenge for producers and regulatory

  17. Relaxations and Interfacial Water Ordering at the Corundum (110) Surface

    SciTech Connect

    Catalano, Jeffrey G.

    2010-09-17

    In situ high resolution specular X-ray reflectivity measurements were used to examine relaxations and interfacial water ordering occurring at the corundum (110)-water interface. Sample preparation affected the resulting surface structure. Annealing in air at 1373 K produced a reconstructed surface formed through an apparently ordered aluminum vacancy. The effect of the reconstruction on in-plane periodicity was not determined. The remaining aluminum sites on the surface maintain full coordination by oxygen and the surface was coated with a layer of physically adsorbed water. Ordering of water further from the surface was not observed. Acid etching of this surface and preparing a surface through annealing at 723 K both produced an unreconstructed surface with identical relaxations and water ordering. Relaxations were confined primarily to the top {approx}4 {angstrom} of the surface and were dominated by an increased distribution width of the fully occupied surface aluminum site and outward relaxation of the oxygen surface functional groups. A layer of adsorbed water fully coated the surface and occurred in two distinct sites. Water above this showed signs of layering and indicated that water ordering extended 7-10 {angstrom} from the surface. Relaxations and the arrangement of interfacial water were nearly identical on both the unreconstructed corundum and isostructural hematite (110) surfaces. Comparison to corundum and hematite (012) suggests that the arrangement of interfacial water is primarily controlled by mineral surface structure.

  18. Water: one molecule, two surfaces, one mistake

    NASA Astrophysics Data System (ADS)

    Vega, Carlos

    2015-05-01

    In order to rigorously evaluate the energy and dipole moment of a certain configuration of molecules, one needs to solve the Schrödinger equation. Repeating this for many different configurations allows one to determine the potential energy surface (PES) and the dipole moment surface (DMS). Since the early days of computer simulation, it has been implicitly accepted that for empirical potentials the charges used to fit the PES should also be used to describe the DMS. This is a mistake. Partial charges are not observable magnitudes. They should be regarded as adjustable fitting parameters. Optimal values used to describe the PES are not necessarily the best to describe the DMS. One could use two fits: one for the PES and the other for the DMS. This is a common practice in the quantum chemistry community, but not used so often by the community performing computer simulations. This idea affects all types of modelling of water (with the exception of ab initio calculations) from coarse-grained to non-polarisable and polarisable models. We anticipate that an area that will benefit dramatically from having both, a good PES and a good DMS, is the modelling of water in the presence of electric fields.

  19. The influence of compost addition on the water repellency of brownfield soils

    NASA Astrophysics Data System (ADS)

    Whelan, Amii; Kechavarzi, Cedric; Sakrabani, Ruben; Coulon, Frederic; Simmons, Robert; Wu, Guozhong

    2010-05-01

    Compost application to brownfield sites, which can facilitate the stabilisation and remediation of contaminants whilst providing adequate conditions for plant growth, is seen as an opportunity to divert biodegradable wastes from landfill and put degraded land back into productive use. However, although compost application is thought to improve soil hydraulic functioning, there is a lack of information on the impact of large amounts of compost on soil water repellency. Water repellency in soils is attributed to the accumulation of hydrophobic organic compounds released as root exudates, fungal and microbial by-products and decomposition of organic matter. It has also been shown that brownfield soils contaminated with petroleum-derived organic contaminants can exhibit strong water repellency, preventing the rapid infiltration of water and leading potentially to surface run off and erosion of contaminated soil. However, hydrophobic organic contaminants are known to become sequestrated by partitioning into organic matter or diffusing into nano- and micropores, making them less available over time (ageing). The effect of large amounts of organic matter addition through compost application on the water repellency of soils contaminated with petroleum-derived organic contaminants requires further investigation. We characterised the influence of compost addition on water repellency in the laboratory by measuring the Water Drop Penetration Time (WDPT), sorptivity and water repellency index through infiltration experiments on soil samples amended with two composts made with contrasting feedstocks (green waste and predominantly meat waste). The treatments consisted of a sandy loam, a clay loam and a sandy loam contaminated with diesel fuel and aged for 3 years, which were amended with the two composts at a rate equivalent to 750t/ha. In addition core samples collected from a brownfield site, amended with compost at three different rates (250, 500 and 750t/ha) in 2007, were

  20. Interregional management of ground and surface water

    USGS Publications Warehouse

    Thomas, H.E.

    1957-01-01

    I feel that there is not a large gap between what we have and what we need for "management" of the people who must give their assent to any program for management of water resources. We need a "generalist" approach in addition to our specialist approach, to achieve a synthesis of the results of the specialist's analysis of specific problems. And as a means of developing these generalists, closer coordination or perhaps "combined operations" of groups of specialists in diverse fields might provide the comprehensive and overall understanding which we need, and which is needed by the general public.

  1. Methods and energy storage devices utilizing electrolytes having surface-smoothing additives

    SciTech Connect

    Xu, Wu; Zhang, Jiguang; Graff, Gordon L; Chen, Xilin; Ding, Fei

    2015-11-12

    Electrodeposition and energy storage devices utilizing an electrolyte having a surface-smoothing additive can result in self-healing, instead of self-amplification, of initial protuberant tips that give rise to roughness and/or dendrite formation on the substrate and anode surface. For electrodeposition of a first metal (M1) on a substrate or anode from one or more cations of M1 in an electrolyte solution, the electrolyte solution is characterized by a surface-smoothing additive containing cations of a second metal (M2), wherein cations of M2 have an effective electrochemical reduction potential in the solution lower than that of the cations of M1.

  2. Organic acids in naturally colored surface waters

    USGS Publications Warehouse

    Lamar, William L.; Goerlitz, D.F.

    1966-01-01

    Most of the organic matter in naturally colored surface waters consists of a mixture of carboxylic acids or salts of these acids. Many of the acids color the water yellow to brown; however, not all of the acids are colored. These acids range from simple to complex, but predominantly they are nonvolatile polymeric carboxylic acids. The organic acids were recovered from the water by two techniques: continuous liquid-liquid extraction with n-butanol and vacuum evaporation at 50?C (centigrade). The isolated acids were studied by techniques of gas, paper, and column chromatography and infrared spectroscopy. About 10 percent of the acids recovered were volatile or could be made volatile for gas chromatographic analysis. Approximately 30 of these carboxylic acids were isolated, and 13 of them were individually identified. The predominant part of the total acids could not be made volatile for gas chromatographic analysis. Infrared examination of many column chromatographic fractions indicated that these nonvolatile substances are primarily polymeric hydroxy carboxylic acids having aromatic and olefinic unsaturation. The evidence suggests that some of these acids result from polymerization in aqueous solution. Elemental analysis of the sodium fusion products disclosed the absence of nitrogen, sulfur, and halogens.

  3. Chapter 5: Surface water quality sampling in streams and canals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Surface water sampling and water quality assessments have greatly evolved in the United States since the 1970s establishment of the Clean Water Act. Traditionally, water quality referred to only the chemical characteristics of the water and its toxicological properties related to drinking water or ...

  4. Surface Tension Mediated Under-Water Adhesion of Rigid Spheres on Soft, Charged Surfaces

    NASA Astrophysics Data System (ADS)

    Sinha, Shayandev; Das, Siddhartha

    2015-11-01

    Understanding the phenomenon of surface-tension-mediated under-water adhesion is necessary for studying a plethora of physiological and technical phenomena, such as the uptake of bacteria or nanoparticle by cells, attachment of virus on bacterial surfaces, biofouling on large ocean vessels and marine devices, etc. This adhesion phenomenon becomes highly non-trivial in case the soft surface where the adhesion occurs is also charged. Here we propose a theory for analyzing such an under-water adhesion of a rigid sphere on a soft, charged surface, represented by a grafted polyelectrolyte layer (PEL). We develop a model based on the minimization of free energy that, in addition to considering the elastic and the surface-tension-mediated adhesion energies, also accounts for the PEL electric double layer (EDL) induced electrostatic energies. We show that in the presence of surface charges, adhesion gets enhanced. This can be explained by the fact that the increase in the elastic energy is better balanced by the lowering of the EDL energy associated with the adhesion process. The entire behaviour is further dictated by the surface tension components that govern the adhesion energy.

  5. Quality of surface water in Missouri, water year 2014

    USGS Publications Warehouse

    Barr, Miya N.

    2015-12-18

    The U.S. Geological Survey, in cooperation with the Missouri Department of Natural Resources, designed and operates a series of monitoring stations on streams and springs throughout Missouri known as the Ambient Water-Quality Monitoring Network. During the 2014 water year (October 1, 2013, through September 30, 2014), data were collected at 74 stations—72 Ambient Water-Quality Monitoring Network stations and 2 U.S. Geological Survey National Stream Quality Assessment Network stations. Dissolved oxygen, specific conductance, water temperature, suspended solids, suspended sediment, Escherichia coli bacteria, fecal coliform bacteria, dissolved nitrate plus nitrite as nitrogen, total phosphorus, dissolved and total recoverable lead and zinc, and select pesticide compound summaries are presented for 71 of these stations. The stations primarily have been classified into groups corresponding to the physiography of the State, primary land use, or unique station types. In addition, a summary of hydrologic conditions in the State including peak discharges, monthly mean discharges, and 7-day low flow is presented.

  6. Quality of surface water in Missouri, water year 2011

    USGS Publications Warehouse

    Barr, Miya N.

    2012-01-01

    The U.S. Geological Survey, in cooperation with the Missouri Department of Natural Resources, designed and operates a series of monitoring stations on streams throughout Missouri known as the Ambient Water-Quality Monitoring Network. During the 2011 water year (October 1, 2010, through September 30, 2011), data were collected at 75 stations—72 Ambient Water-Quality Monitoring Network stations, 2 U.S. Geological Survey National Stream Quality Accounting Network stations, and 1 spring sampled in cooperation with the U.S. Forest Service. Dissolved oxygen, specific conductance, water temperature, suspended solids, suspended sediment, fecal coliform bacteria, Escherichia coli bacteria, dissolved nitrate plus nitrite, total phosphorus, dissolved and total recoverable lead and zinc, and select pesticide compound summaries are presented for 72 of these stations. The stations primarily have been classified into groups corresponding to the physiography of the State, primary land use, or unique station types. In addition, a summary of hydrologic conditions in the State including peak discharges, monthly mean discharges, and 7-day low flow is presented.

  7. Quality of surface water in Missouri, water year 2010

    USGS Publications Warehouse

    Barr, Miya N.

    2011-01-01

    The U.S. Geological Survey, in cooperation with the Missouri Department of Natural Resources, designs and operates a series of monitoring stations on streams throughout Missouri known as the Ambient Water-Quality Monitoring Network. During the 2010 water year (October 1, 2009 through September 30, 2010), data were collected at 75 stations-72 Ambient Water-Quality Monitoring Network stations, 2 U.S. Geological Survey National Stream Quality Accounting Network stations, and 1 spring sampled in cooperation with the U.S. Forest Service. Dissolved oxygen, specific conductance, water temperature, suspended solids, suspended sediment, fecal coliform bacteria, Escherichia coli bacteria, dissolved nitrate plus nitrite, total phosphorus, dissolved and total recoverable lead and zinc, and select pesticide compound summaries are presented for 72 of these stations. The stations primarily have been classified into groups corresponding to the physiography of the State, primary land use, or unique station types. In addition, a summary of hydrologic conditions in the State including peak discharges, monthly mean discharges, and 7-day low flow is presented.

  8. Quality of surface water in Missouri, water year 2009

    USGS Publications Warehouse

    Barr, Miya N.

    2010-01-01

    The U.S. Geological Survey, in cooperation with the Missouri Department of Natural Resources, designs and operates a series of monitoring stations on streams throughout Missouri known as the Ambient Water-Quality Monitoring Network. During the 2009 water year (October 1, 2008, through September 30, 2009), data were collected at 75 stations-69 Ambient Water-Quality Monitoring Network stations, 2 U.S. Geological Survey National Stream Quality Accounting Network stations, 1 spring sampled in cooperation with the U.S. Forest Service, and 3 stations sampled in cooperation with the Elk River Watershed Improvement Association. Dissolved oxygen, specific conductance, water temperature, suspended solids, suspended sediment, fecal coliform bacteria, Escherichia coli bacteria, dissolved nitrate plus nitrite, total phosphorus, dissolved and total recoverable lead and zinc, and select pesticide compound summaries are presented for 72 of these stations. The stations primarily have been classified into groups corresponding to the physiography of the State, primary land use, or unique station types. In addition, a summary of hydrologic conditions in the State including peak discharges, monthly mean discharges, and seven-day low flow is presented.

  9. Surface water risk assessment of pesticides in Ethiopia.

    PubMed

    Teklu, Berhan M; Adriaanse, Paulien I; Ter Horst, Mechteld M S; Deneer, John W; Van den Brink, Paul J

    2015-03-01

    Scenarios for future use in the pesticide registration procedure in Ethiopia were designed for 3 separate Ethiopian locations, which are aimed to be protective for the whole of Ethiopia. The scenarios estimate concentrations in surface water resulting from agricultural use of pesticides for a small stream and for two types of small ponds. Seven selected pesticides were selected since they were estimated to bear the highest risk to humans on the basis of volume of use, application rate and acute and chronic human toxicity, assuming exposure as a result of the consumption of surface water. Potential ecotoxicological risks were not considered as a selection criterion at this stage. Estimates of exposure concentrations in surface water were established using modelling software also applied in the EU registration procedure (PRZM and TOXSWA). Input variables included physico-chemical properties, and data such as crop calendars, irrigation schedules, meteorological information and detailed application data which were specifically tailored to the Ethiopian situation. The results indicate that for all the pesticides investigated the acute human risk resulting from the consumption of surface water is low to negligible, whereas agricultural use of chlorothalonil, deltamethrin, endosulfan and malathion in some crops may result in medium to high risk to aquatic species. The predicted environmental concentration estimates are based on procedures similar to procedures used at the EU level and in the USA. Addition of aquatic macrophytes as an ecotoxicological endpoint may constitute a welcome future addition to the risk assessment procedure. Implementation of the methods used for risk characterization constitutes a good step forward in the pesticide registration procedure in Ethiopia.

  10. Surface water risk assessment of pesticides in Ethiopia.

    PubMed

    Teklu, Berhan M; Adriaanse, Paulien I; Ter Horst, Mechteld M S; Deneer, John W; Van den Brink, Paul J

    2015-03-01

    Scenarios for future use in the pesticide registration procedure in Ethiopia were designed for 3 separate Ethiopian locations, which are aimed to be protective for the whole of Ethiopia. The scenarios estimate concentrations in surface water resulting from agricultural use of pesticides for a small stream and for two types of small ponds. Seven selected pesticides were selected since they were estimated to bear the highest risk to humans on the basis of volume of use, application rate and acute and chronic human toxicity, assuming exposure as a result of the consumption of surface water. Potential ecotoxicological risks were not considered as a selection criterion at this stage. Estimates of exposure concentrations in surface water were established using modelling software also applied in the EU registration procedure (PRZM and TOXSWA). Input variables included physico-chemical properties, and data such as crop calendars, irrigation schedules, meteorological information and detailed application data which were specifically tailored to the Ethiopian situation. The results indicate that for all the pesticides investigated the acute human risk resulting from the consumption of surface water is low to negligible, whereas agricultural use of chlorothalonil, deltamethrin, endosulfan and malathion in some crops may result in medium to high risk to aquatic species. The predicted environmental concentration estimates are based on procedures similar to procedures used at the EU level and in the USA. Addition of aquatic macrophytes as an ecotoxicological endpoint may constitute a welcome future addition to the risk assessment procedure. Implementation of the methods used for risk characterization constitutes a good step forward in the pesticide registration procedure in Ethiopia. PMID:25481716

  11. Surface Modified Particles By Multi-Step Addition And Process For The Preparation Thereof

    DOEpatents

    Cook, Ronald Lee; Elliott, Brian John; Luebben, Silvia DeVito; Myers, Andrew William; Smith, Bryan Matthew

    2006-01-17

    The present invention relates to a new class of surface modified particles and to a multi-step surface modification process for the preparation of the same. The multi-step surface functionalization process involves two or more reactions to produce particles that are compatible with various host systems and/or to provide the particles with particular chemical reactivities. The initial step comprises the attachment of a small organic compound to the surface of the inorganic particle. The subsequent steps attach additional compounds to the previously attached organic compounds through organic linking groups.

  12. Impact of Water Withdrawals from Groundwater and Surface Water on Continental Water Storage Variations

    NASA Technical Reports Server (NTRS)

    Doell, Petra; Hoffmann-Dobrev, Heike; Portmann, Felix T.; Siebert, Stefan; Eicker, Annette; Rodell, Matthew; Strassberg, Gil

    2011-01-01

    Humans have strongly impacted the global water cycle, not only water flows but also water storage. We have performed a first global-scale analysis of the impact of water withdrawals on water storage variations, using the global water resources and use model WaterGAP. This required estimation of fractions of total water withdrawals from groundwater, considering five water use sectors. According to our assessment, the source of 35% of the water withdrawn worldwide (4300 cubic km/yr during 1998-2002) is groundwater. Groundwater contributes 42%, 36% and 27% of water used for irrigation, households and manufacturing, respectively, while we assume that only surface water is used for livestock and for cooling of thermal power plants. Consumptive water use was 1400 cubic km/yr during 1998-2002. It is the sum of the net abstraction of 250 cubic km/yr of groundwater (taking into account evapotranspiration and return flows of withdrawn surface water and groundwater) and the net abstraction of 1150 km3/yr of surface water. Computed net abstractions indicate, for the first time at the global scale, where and when human water withdrawals decrease or increase groundwater or surface water storage. In regions with extensive surface water irrigation, such as Southern China, net abstractions from groundwater are negative, i.e. groundwater is recharged by irrigation. The opposite is true for areas dominated by groundwater irrigation, such as in the High Plains aquifer of the central USA, where net abstraction of surface water is negative because return flow of withdrawn groundwater recharges the surface water compartments. In intensively irrigated areas, the amplitude of seasonal total water storage variations is generally increased due to human water use; however, in some areas, it is decreased. For the High Plains aquifer and the whole Mississippi basin, modeled groundwater and total water storage variations were compared with estimates of groundwater storage variations based on

  13. Europa: Divining Water from Surface Geology

    NASA Astrophysics Data System (ADS)

    Pappalardo, R. T.

    2001-12-01

    Europa's surface geology as viewed by Galileo imaging suggests a thin brittle lithosphere above a warm (potentially salt-rich) ice layer that is at least in part convecting, in turn situated above a liquid water ocean. This configuration is consistent with thermal and geochemical modeling, and with Galileo magnetometer and NIMS results, which suggest that Europa may have a salty global-scale subsurface ocean at relatively shallow depths (~20-30 km). Dynamical modeling and visible crater density suggests a surface age of ~50 million years, implying that Europa is probably still geologically active today. Large shallow craters and even larger multi-ringed structures imply impact into low-viscosity (warm) subsurface material. The satellite's bright plains are criss-crossed by narrow troughs and enigmatic double ridges (paired ridges separated by a medial trough); a morphological sequence (and implied evolutionary sequence) exists from isolated troughs to doublet ridges to wider and more complex ridge morphologies. Troughs are inferred as widened fractures formed though tensile and shear failure in response to global stressing of the ice shell above liquid water. Several models exist to explain ridges, but the most likely is one in which localized shear heating triggers upwelling of warm ice along fracture zones. Triple bands are ridges with diffuse ruddy margins that may have formed through thermal alteration and/or partial melting of briny ice. Wider pull-apart bands represent complete separation and spreading of the icy lithosphere, in a manner broadly analogous to terrestrial sea-floor spreading. Europa's global lineament pattern implies that nonsynchronous rotation and orbital flexing ("diurnal" stressing) have worked in tandem to deform the surface. Diurnal stressing can explain Europa's extremely enigmatic cycloid ridge and fracture patterns, and may drive rapid strike-slip faulting along ridges. Because significant tidal amplitude is necessary to produce

  14. Qualitative Uncertainty Assessment for Distributed Surface Water Quality Models

    NASA Astrophysics Data System (ADS)

    Meixner, T.; Bubb, K.; van Griensven, A.

    2006-12-01

    Water quality models are often used to aid water quality regulators in the United States and around the world make critical decisions about how to improve water quality. Basin scale water quality models generally simplify spatial complexity to some degree. This problem is especially relevant in water quality modeling since the sources of pollution as well as the hydrologic drivers vary spatially across the landscape. The spatial complexity problem also presents specific challenges for estimating model predictive uncertainty. Questions of how to integrate multiple sources of stream water and water quality data at multiple locations are likely to be even more daunting than they are for surface water hydrologic models. At this time, given the complexity of water quality models and the general lack of data available, true statistical techniques of integrating, multiple data sources and calculating uncertainty bounds are probably not reasonable approaches. For this reason, we propose evaluation methods that are not based on statistics in order to evaluate the fit-to- purpose of particular model applications. Within SWAT2005, both a statistical method for uncertainty analysis, ParaSol, and an evaluation method, SUNGLASSES, have been incorporated. Additionally weighted averages of prediction errors are integrated into a global objective function and used to evaluate the reasonableness of model assumptions. This integration occurs across multiple objective functions and multiple locations. These methods have been applied in the context of a hypothetical water quality control problem in the San Jacinto watershed in southern California. The analysis includes an extension of the uncertainty analysis into its economic implications. The economic impact of the uncertainty methods proposed here are compared to more traditional uncertainty methods. The economic implications of uncertainty are shown to be important but only under circumstances where water quality targets are close

  15. The impact of land use on microbial surface water pollution.

    PubMed

    Schreiber, Christiane; Rechenburg, Andrea; Rind, Esther; Kistemann, Thomas

    2015-03-01

    Our knowledge relating to water contamination from point and diffuse sources has increased in recent years and there have been many studies undertaken focusing on effluent from sewage plants or combined sewer overflows. However, there is still only a limited amount of microbial data on non-point sources leading to diffuse pollution of surface waters. In this study, the concentrations of several indicator micro-organisms and pathogens in the upper reaches of a river system were examined over a period of 16 months. In addition to bacteria, diffuse pollution caused by Giardia lamblia and Cryptosporidium spp. was analysed. A single land use type predestined to cause high concentrations of all microbial parameters could not be identified. The influence of different land use types varies between microbial species. The microbial concentration in river water cannot be explained by stable non-point effluent concentrations from different land use types. There is variation in the ranking of the potential of different land use types resulting in surface water contamination with regard to minimum, median and maximum effects. These differences between median and maximum impact indicate that small-scale events like spreading manure substantially influence the general contamination potential of a land use type and may cause increasing micro-organism concentrations in the river water by mobilisation during the next rainfall event. PMID:25456147

  16. A new device for collecting time-integrated water samples from springs and surface water bodies

    USGS Publications Warehouse

    Panno, S.V.; Krapac, I.G.; Keefer, D.A.

    1998-01-01

    A new device termed the 'seepage sampler' was developed to collect representative water samples from springs, streams, and other surface-water bodies. The sampler collects composite, time-integrated water samples over short (hours) or extended (weeks) periods without causing significant changes to the chemical composition of the samples. The water sample within the sampler remains at the ambient temperature of the water body and does not need to be cooled. Seepage samplers are inexpensive to construct and easy to use. A sampling program of numerous springs and/or streams can be designed at a relatively low cost through the use of these samplers. Transient solutes migrating through such flow systems, potentially unnoticed by periodic sampling, may be detected. In addition, the mass loading of solutes (e.g., agrichemicals) may be determined when seepage samplers are used in conjunction with discharge measurements.

  17. Facile synthesis of SrCO3 nanostructures in methanol/water solution without additives

    PubMed Central

    2012-01-01

    Highly dispersive strontium carbonate (SrCO3) nanostructures with uniform dumbbell, ellipsoid, and rod-like morphologies were synthesized in methanol solution without any additives. These SrCO3 were characterized by X-ray diffraction, field emission scanning electron microscopy, and N2 adsorption-desorption. The results showed that the reaction temperature and the methanol/water ratio had important effects on the morphologies of SrCO3 particles. The dumbbell-like SrCO3 exhibited a Broader-Emmett-Teller surface area of 14.9 m2 g−1 and an average pore size of about 32 nm with narrow pore size distribution. The formation mechanism of the SrCO3 crystal was preliminary presented. PMID:22704526

  18. Evaluation of the Surface-Water Quantity, Surface-Water Quality, and Rainfall Data-Collection Programs in Hawaii, 1994

    USGS Publications Warehouse

    Fontaine, Richard A.

    1996-01-01

    This report documents the results of an evaluation of the surface-water quantity, surface-water quality, and rainfall data-collection programs in Hawaii. Fourteen specific issues and related goals were identified for the surface-water quantity program and a geographic information systems (GIS) data base was developed summarizing information for all surface-water stream gages that have been operated in Hawaii by the U.S. Geological Survey. Changes in status, which for some gages includes discontinuing operation, need to be considered at 42 sites where data are currently collected. The current surface-water quantity data base was determined to be adequate to address only two of the 14 specific issues and related goals. Alternatives were identified to address the areas where future issues and goals could not be adequately addressed. Options include new and expanded data collection, use of regional regression analyses, hydrologic and hydraulic modeling, and analysis and publication of existing data. A total of 47 streams were identified where additional stream-gaging stations are needed. Evaluation of the surface-water quality program was limited to a description of the U.S. Geological Survey's historical and existing programs and available analyses of data. Limitations of the program are described which primarily included lack of data regarding suspended sediment, land-use effects, quality of stream discharge to oceans, background water quality and nonpoint sources of contamination. Evaluation of the rainfall data program indicated that identified future goals could be discussed as either regional, systems related, current needs, forecasting, water quality, or trend analysis related. To address these goals, data from about 2,000 rain gages, 528 of which are active, are available. Data were found to only partially meet identified goals. Alternatives discussed to address the limitations include the need for more recording gages, primarily in areas of high rainfall

  19. Surface-water availability, Tuscaloosa County, Alabama

    USGS Publications Warehouse

    Knight, Alfred L.; Davis, Marvin E.

    1975-01-01

    The average annual runoff, about 1,270 mgd (million gallons per day), originating in Tuscaloosa County is equivalent to 20 inches or 0.95 mgd per square mile. The Black Warrior and Sipsey Rivers, the largest streams in the county, have average flows of 5,230 mgd and 580 mgd, respectively, where they leave the county, and median annual 7-day low flows in excess of 150 mgd and 35 mgd, respectively. North River, Big Sandy Creek, and Hurricane Creek have average flows in excess of 100 mgd and median annual 7-day low flows in excess of 2 mgd. Surface water generally contains less than 100 mg/l (milligrams per liter) dissolved solids, less than 10 mg/l chloride, and is soft to moderately hard. Streams having the higher hardness and the higher dissolved-solids content are in eastern Tuscaloosa County.

  20. Water Resources Data, Florida, Water Year 2003, Volume 3A: Southwest Florida Surface Water

    USGS Publications Warehouse

    Kane, R.L.; Fletcher, W.L.

    2004-01-01

    Water resources data for the 2003 water year in Florida consist of continuous or daily discharges for 385 streams, periodic discharge for 13 streams, continuous daily stage for 255 streams, periodic stage for 13 streams, peak stage for 36 streams and peak discharge for 36 streams, continuous or daily elevations for 13 lakes, periodic elevations for 46 lakes; continuous ground-water levels for 441 wells, periodic ground-water levels for 1,227 wells, and quality-of-water data for 133 surface-water sites and 308 wells. The data for Southwest Florida include records of stage, discharge, and water quality of streams; stage, contents, water quality of lakes and reservoirs, and water levels and water quality of ground-water wells. Volume 3A contains continuous or daily discharge for 103 streams, periodic discharge for 7 streams, continuous or daily stage for 67 streams, periodic stage for 13 streams, peak stage and discharge for 8 streams, continuous or daily elevations for 2 lakes, periodic elevations for 26 lakes, and quality-of-water data for 62 surface-water sites. These data represent the national Water Data System records collected by the U.S. Geological Survey and cooperating local, state, and federal agencies in Florida.

  1. Water Resources Data, Florida, Water Year 2001, Volume 3A. Southwest Florida Surface Water

    USGS Publications Warehouse

    Stoker, Y.E.; Kane, R.L.; Fletcher, W.L.

    2002-01-01

    Water resources data for the 2001 water year in Florida consist of continuous or daily discharges for 406 streams, periodic discharge for 12 streams, continuous daily stage for 142 streams, periodic stage for 12 streams, peak stage and discharge for 37 streams, continuous or daily elevations for 11 lakes, periodic elevations for 30 lakes; continuous ground-water levels for 424 wells, periodic ground-water levels for 1,426 wells, and quality-of-water data for 80 surface-water sites and 245 wells. The data for Southwest Florida include records of stage, discharge, and water quality of streams; stage, contents, water quality of lakes and reservoirs, and water levels and water quality of ground-water wells. Volume 3A contains continuous or daily discharge for 83 streams, periodic discharge for 10 streams, continuous or daily stage for 43 streams, peak stage and discharge for 8 streams, continuous or daily elevations for 2 lakes, periodic elevations for 26 lakes, and quality-of-water data for 37 surface-water sites. These data represent the national Water Data System records collected by the U.S. Geological Survey and cooperating local, state, and federal agencies in Florida.

  2. Water Resources Data, Florida, Water Year 2002, Volume 3A. Southwest Florida Surface Water

    USGS Publications Warehouse

    Kane, R.L.; Fletcher, W.L.

    2003-01-01

    Water resources data for the 2002 water year in Florida consist of continuous or daily discharges for 392 streams, periodic discharge for 15 streams, continuous daily stage for 191 streams, periodic stage for 13 streams, peak stage for 33 streams and peak discharge for 33 streams, continuous or daily elevations for 14 lakes, periodic elevations for 49 lakes; continuous ground-water levels for 418 wells, periodic ground-water levels for 1,287 wells, and quality-of-water data for 116 surface-water sites and 291 wells. The data for Southwest Florida include records of stage, discharge, and water quality of streams; stage, contents, water quality of lakes and reservoirs, and water levels and water quality of ground-water wells. Volume 3A contains continuous or daily discharge for 99 streams, periodic discharge for 11 streams, continuous or daily stage for 63 streams, peak stage and discharge for 7 streams, continuous or daily elevations for 2 lakes, periodic elevations for 26 lakes, and quality-of-water data for 59 surface-water sites. These data represent the national Water Data System records collected by the U.S. Geological Survey and cooperating local, state, and federal agencies in Florida.

  3. Water resources data, Florida, water year 2004, volume 3A: southwest Florida surface water

    USGS Publications Warehouse

    Kane, Richard L.

    2004-01-01

    Water resources data for the 2004 water year in Florida consist of continuous or daily discharges for 405 streams, periodic discharge for 12 streams, continuous daily stage for 159 streams, periodic stage for 19 streams, peak stage for 30 streams and peak discharge for 30 streams, continuous or daily elevations for 14 lakes, periodic elevations for 23 lakes; continuous ground-water levels for 408 wells, periodic ground-water levels for 1,188 wells, and quality-of-water data for 140 surface-water sites and 240 wells. The data for Southwest Florida include records of stage, discharge, and water quality of streams; stage, contents, water quality of lakes and reservoirs, and water levels and water quality of ground-water wells. Volume 3A contains continuous or daily discharge for 104 streams, periodic discharge for 6 streams, continuous or daily stage for 36 streams, periodic stage for 14 streams, peak stage and discharge for 8 streams, continuous or daily elevations for 2 lakes, periodic elevations for 3 lakes, and quality-of-water data for 58 surface-water sites. These data represent the national Water Data System records collected by the U.S. Geological Survey and cooperating local, state, and federal agencies in Florida.

  4. Water resources data, Florida, water year 2005. Volume 3A: Southwest Florida surface water

    USGS Publications Warehouse

    Kane, Richard L.; Dickman, Mark

    2005-01-01

    Water resources data for the 2005 water year in Florida consist of continuous or daily discharges for 429 streams, periodic discharge for 9 streams, continuous or daily stage for 218 streams, periodic stage for 5 streams, peak stage for 28 streams and peak discharge for 28 streams, continuous or daily elevations for 15 lakes, periodic elevations for 23 lakes; continuous ground-water levels for 401 wells, periodic ground-water levels for 1,098 wells, and quality-of-water data for 211 surface-water sites and 208 wells. The data for Southwest Florida include records of stage, discharge, and water quality of streams; stage, contents, water quality of lakes and reservoirs, and water levels and water quality of ground-water wells. Volume 3A contains records for continuous or daily discharge for 113 streams, periodic discharge for 4 streams, continuous or daily stage for 80 streams, periodic stage for 2 stream, peak stage and discharge for 8 streams, continuous or daily elevations for 3 lakes, continous or daily elevations for 3 lakes, and quality of water for 75 surface water sites. These data represent the national Water Data System records collected by the U.S. Geological Survey and cooperating local, state, and federal agencies in Florida.

  5. Metolachlor and atrazine fate in surface water systems

    SciTech Connect

    Rice, P.J.; Anderson, T.A.; Coats, J.R.

    1995-12-31

    The detection of pesticides in surface water and ground water provokes concern involving human health risks associated with pesticide exposure. Monitoring studies of surface waters have detected concentrations of herbicides that exceed the U.S. Environmental Protection Agency proposed maximum contamination level (MCL) for drinking water. Conventional water treatment processes do not remove many herbicides. Tap water drawn from surface-water sources has been reported to contain levels of herbicides above the regulatory limits. There is current interest in the use of artificial wetlands and macrophyte-cultured ponds in waste-water-treatment systems. Aquatic plant-based water treatment systems improve waste water effluent by solid filtration and nutrient assimilation. Various aquatic plants have been shown to accumulate metals, absorb inorganic ions, and accelerate the biodegradation of complex organics. Our research evaluates the fate of metolachlor and atrazine in surface water, surface water/sediment, and surface water/aquatic plant incubation systems to study the influence of sediment and aquatic plants in the removal and biotransformation of herbicides from contaminated waters. Aquatic macrophyte systems may prove to be useful in the remediation of herbicide contaminated surface waters in water treatment facilities or in the reduction of herbicide concentrations from tile drain effluents prior to entering watersheds.

  6. Water resources data, Wyoming, water year 2004; Volume 1. Surface water; with List of discontinued and active surface-water, water-quality, sediment, and biological stations

    USGS Publications Warehouse

    Watson, K.R.; Woodruff, R.E.; Laidlaw, G.A.; Clark, M.L.; Miller, K.A.

    2005-01-01

    Water resources data for the 2004 water year for Wyoming consist of records of stage, discharge and water quality of streams; stage and contents of lakes and reservoirs, and water levels and water quality of ground water. Volume 1 of this report contains discharge records for 164 gaging stations; water quality for 43 gaging stations and 45 ungaged stations, and stage and contents for one reservoir. Volume 2 of this report contains water levels records for 64 wells. Additional water data were collected at various sites, not part of the systematic data collection program, and are published as miscellaneous measurements. These data represent part of the National Water Information System operated by the U.S. Geological Survey and cooperating State and Federal agencies in Wyoming.

  7. Concentration Data for Anthropogenic Organic Compounds in Ground Water, Surface Water, and Finished Water of Selected Community Water Systems in the United States, 2002-05

    USGS Publications Warehouse

    Carter, Janet M.; Delzer, Gregory C.; Kingsbury, James A.; Hopple, Jessica A.

    2007-01-01

    The National Water-Quality Assessment Program of the U.S. Geological Survey began implementing Source Water-Quality Assessments (SWQAs) in 2001 that focus on characterizing the quality of source water and finished water of aquifers and major rivers used by some of the larger community water systems (CWSs) in the United States. As used for SWQA studies, source water is the raw (ambient) water collected at the supply well prior to water treatment (for ground water) or the raw (ambient) water collected from the river near the intake (for surface water), and finished water is the water that is treated and ready to be delivered to consumers. Finished water is collected before entering the distribution system. SWQA studies are conducted in two phases, and the objectives of SWQA studies are twofold: (1) to determine the occurrence and, for rivers, seasonal changes in concentrations of a broad list of anthropogenic organic compounds (AOCs) in aquifers and rivers that have some of the largest withdrawals for drinking-water supply (phase 1), and (2) for those AOCs found to occur most frequently in source water, characterize the extent to which these compounds are present in finished water (phase 2). These objectives were met for SWQA studies by collecting ground-water and surface-water (source) samples and analyzing these samples for 258 AOCs during phase 1. Samples from a subset of wells and surface-water sites located in areas with substantial agricultural production in the watershed were analyzed for 19 additional AOCs, for a total of 277 compounds analyzed for SWQA studies. The 277 compounds were classified according to the following 13 primary use or source groups: (1) disinfection by-products; (2) fumigant-related compounds; (3) fungicides; (4) gasoline hydrocarbons, oxygenates, and oxygenate degradates; (5) herbicides and herbicide degradates; (6) insecticides and insecticide degradates; (7) manufacturing additives; (8) organic synthesis compounds; (9) pavement- and

  8. Surface-Water and Ground-Water Interactions in the Central Everglades, Florida

    USGS Publications Warehouse

    Harvey, Judson W.; Newlin, Jessica T.; Krest, James M.; Choi, Jungyill; Nemeth, Eric A.; Krupa, Steven L.

    2004-01-01

    Recharge and discharge are hydrological processes that cause Everglades surface water to be exchanged for subsurface water in the peat soil and the underlying sand and limestone aquifer. These interactions are thought to be important to water budgets, water quality, and ecology in the Everglades. Nonetheless, relatively few studies of surface water and ground water interactions have been conducted in the Everglades, especially in its vast interior areas. This report is a product of a cooperative investigation conducted by the USGS and the South Florida Water Management District (SFWMD) aimed at developing and testing techniques that would provide reliable estimates of recharge and discharge in interior areas of WCA-2A (Water Conservation Area 2A) and several other sites in the central Everglades. The new techniques quantified flow from surface water to the subsurface (recharge) and the opposite (discharge) using (1) Darcy-flux calculations based on measured vertical gradients in hydraulic head and hydraulic conductivity of peat; (2) modeling transport through peat and decay of the naturally occurring isotopes 224Ra and 223Ra (with half-lives of 4 and 11 days, respectively); and (3) modeling transport and decay of naturally occurring and 'bomb-pulse' tritium (half-life of 12.4 years) in ground water. Advantages and disadvantages of each method for quantifying recharge and discharge were compared. In addition, spatial and temporal variability of recharge and discharge were evaluated and controlling factors identified. A final goal was to develop appropriately simplified (that is, time averaged) expressions of the results that will be useful in addressing a broad range of hydrological and ecological problems in the Everglades. Results were compared with existing information about water budgets from the South Florida Water Management Model (SFWMM), a principal tool used by the South Florida Water Management District to plan many of the hydrological aspects of the

  9. The Synergism Between Heat and Mass Transfer Additive and Advanced Surfaces in Aqueous LiBr Horizontal Tube Absorbers

    SciTech Connect

    Miller, W.A.

    1999-03-24

    Experiments were conducted in a laboratory to investigate the absorption of water vapor into a falling-film of aqueous lithium bromide (LiBr). A mini-absorber test stand was used to test smooth tubes and a variety of advanced tube surfaces placed horizontally in a single-row bundle. The bundle had six copper tubes; each tube had an outside diameter of 15.9-mm and a length of 0.32-m. A unique feature of the stand is its ability to operate continuously and support testing of LiBr brine at mass fractions {ge} 0.62. The test stand can also support testing to study the effect of the failing film mass flow rate, the coolant mass flow rate, the coolant temperature, the absorber pressure and the tube spacing. Manufacturers of absorption chillers add small quantities of a heat and mass transfer additive to improve the performance of the absorbers. The additive causes surface stirring which enhances the transport of absorbate into the bulk of the film. Absorption may also be enhanced with advanced tube surfaces that mechanically induce secondary flows in the falling film without increasing the thickness of the film. Several tube geometry's were identified and tested with the intent of mixing the film and renewing the interface with fresh solution from the tube wall. Testing was completed on a smooth tube and several different externally enhanced tube surfaces. Experiments were conducted over the operating conditions of 6.5 mm Hg absorber pressure, coolant temperatures ranging from 20 to 35 C and LiBr mass fractions ranging from 0.60 through 0.62. Initially the effect of tube spacing was investigated for the smooth tube surface, tested with no heat and mass transfer additive. Test results showed the absorber load and the mass absorbed increased as the tube spacing increased because of the improved wetting of the tube bundle. However, tube spacing was not a critical factor if heat and mass transfer additive was active in the mini-absorber. The additive dramatically affected

  10. Quality of Surface Water in Missouri, Water Year 2008

    USGS Publications Warehouse

    Otero-Benitez, William; Davis, Jerri V.

    2009-01-01

    The U.S. Geological Survey, in cooperation with the Missouri Department of Natural Resources, designed and operates a series of monitoring stations on streams throughout Missouri known as the Ambient Water-Quality Monitoring Network. During the 2008 water year (October 1, 2007, through September 30, 2008), data were collected at 67 stations, including two U.S. Geological Survey National Stream Quality Accounting Network stations and one spring sampled in cooperation with the U.S. Forest Service. Dissolved oxygen, specific conductance, water temperature, suspended solids, suspended sediment, fecal coliform bacteria, Escherichia coli bacteria, dissolved nitrate plus nitrite, total phosphorus, dissolved and total recoverable lead and zinc, and selected pesticide data summaries are presented for 64 of these stations. The stations primarily have been classified into groups corresponding to the physiography of the State, primary land use, or unique station types. In addition, a summary of hydrologic conditions in the State including peak discharges, monthly mean discharges, and seven-day low flow is presented.

  11. Leaching of additives from construction materials to urban storm water runoff.

    PubMed

    Burkhardt, M; Zuleeg, S; Vonbank, R; Schmid, P; Hean, S; Lamani, X; Bester, K; Boller, M

    2011-01-01

    Urban water management requires further clarification about pollutants in storm water. Little is known about the release of organic additives used in construction materials and the impact of these compounds to storm water runoff. We investigated sources and pathways of additives used in construction materials, i.e., biocides in facades' render as well as root protection products in bitumen membranes for rooftops. Under wet-weather conditions, the concentrations of diuron, terbutryn, carbendazim, irgarol 1051 (all from facades) and mecoprop in storm water and receiving water exceeded the predicted no-effect concentrations values and the Swiss water quality standard of 0.1 microg/L. Under laboratory conditions maximum concentrations of additives were in the range of a few milligrams and a few hundred micrograms per litre in runoff of facades and bitumen membranes. Runoff from aged materials shows approximately one to two orders of magnitude lower concentrations. Concentrations decreased also during individual runoff events. In storm water and receiving water the occurrence of additives did not follow the typical first flush model. This can be explained by the release lasting over the time of rainfall and the complexity of the drainage network. Beside the amounts used, the impact of construction materials containing hazardous additives on water quality is related clearly to the age of the buildings and the separated sewer network. The development of improved products regarding release of hazardous additives is the most efficient way of reducing the pollutant load from construction materials in storm water runoff.

  12. Surface Wave Driven Air-Water Plasmas

    NASA Astrophysics Data System (ADS)

    Tatarova, Elena; Henriques, Julio; Ferreira, Carlos

    2013-09-01

    The performance of a surface wave driven air-water plasma source operating at atmospheric pressure and 2.45 GHz has been analyzed. A 1D model has been developed in order to describe in detail the creation and loss processes of active species of interest and to provide a complete characterization of the axial structure of the source, including the discharge and the afterglow zones. The main electron creation channel was found to be the associative ionization process N +O -->NO+ + e. The NO(X) relative density in the afterglow plasma jet ranges from 1.2% to 1.6% depending on power and water percentage according to the model predictions and the measurements. Other types of species such as NO2 and nitrous acid HNO2 have also been detected by mass and FT-IR spectroscopy. Furthermore, high densities of O2(a1Δg) singlet delta oxygen molecules and OH radicals (1% and 5%, respectively) can be achieved in the discharge zone. In the late afterglow the O2(a1Δg) density is about 0.1% of the total density. The plasma source has a flexible operation and potential for channeling the energy in ways that maximize the density of active species of interest. This study was funded by the Foundation for Science and Technology, Portuguese Ministry of Education and Science, under the research contract PTDC/FIS/108411/2008.

  13. 75 FR 41725 - Food Additives Permitted in Feed and Drinking Water of Animals; Ammonium Formate

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-19

    ... Additives Permitted in Feed and Drinking Water of Animals; Ammonium Formate AGENCY: Food and Drug... regulations for food additives permitted in feed and drinking water of animals to provide for the safe use of ammonium formate as an acidifying agent in swine feed. This action is in response to a food...

  14. Surface water quality-assurance plan, U.S. Geological Survey, Kentucky Water Science Center, water year 2006

    USGS Publications Warehouse

    Griffin, Michael S.

    2006-01-01

    This Surface Water Quality-Assurance Plan documents the standards, policies, and procedures used by the Kentucky Water Science Center for activities related to the collection, processing, storage, analysis, and publication of surface-water data.

  15. Characterization and analysis of surface notches on Ti-alloy plates fabricated by additive manufacturing techniques

    NASA Astrophysics Data System (ADS)

    Chan, Kwai S.

    2015-12-01

    Rectangular plates of Ti-6Al-4V with extra low interstitial (ELI) were fabricated by layer-by-layer deposition techniques that included electron beam melting (EBM) and laser beam melting (LBM). The surface conditions of these plates were characterized using x-ray micro-computed tomography. The depth and radius of surface notch-like features on the LBM and EBM plates were measured from sectional images of individual virtual slices of the rectangular plates. The stress concentration factors of individual surface notches were computed and analyzed statistically to determine the appropriate distributions for the notch depth, notch radius, and stress concentration factor. These results were correlated with the fatigue life of the Ti-6Al-4V ELI alloys from an earlier investigation. A surface notch analysis was performed to assess the debit in the fatigue strength due to the surface notches. The assessment revealed that the fatigue lives of the additively manufactured plates with rough surface topographies and notch-like features are dominated by the fatigue crack growth of large cracks for both the LBM and EBM materials. The fatigue strength reduction due to the surface notches can be as large as 60%-75%. It is concluded that for better fatigue performance, the surface notches on EBM and LBM materials need to be removed by machining and the surface roughness be improved to a surface finish of about 1 μm.

  16. Effects of extreme pressure additive chemistry on rolling element bearing surface durability

    SciTech Connect

    Evans, Ryan D.; Nixon, H. P.; Darragh, Craig V.; Howe, Jane Y; Coffey, Dorothy W

    2007-01-01

    Lubricant additives have been known to affect rolling element bearing surface durability for many years. Tapered roller bearings were used in fatigue testing of lubricants formulated with gear oil type additive systems. These systems have sulfur- and phosphoruscontaining compounds used for gear protection as well as bearing lubrication. Several variations of a commercially available base additive formulation were tested having modified sulfur components. The variations represent a range of ''active'' extreme pressure (EP) chemistries. The bearing fatigue test results were compared with respect to EP formulation and test conditions. Inner ring near-surface material in selected test bearings was evaluated on two scales: the micrometer scale using optical metallography and the nanometer scale using transmission electron microscopy (TEM). Focused-ion beam (FIB) techniques were used for TEM specimen preparation. Imaging and chemical analysis of the bearing samples revealed near-surface material and tribofilm characteristics. These results are discussed with respect to the relative fatigue lives.

  17. Enhancing Surface Finish of Additively Manufactured Titanium and Cobalt Chrome Elements Using Laser Based Finishing

    NASA Astrophysics Data System (ADS)

    Gora, Wojciech S.; Tian, Yingtao; Cabo, Aldara Pan; Ardron, Marcus; Maier, Robert R. J.; Prangnell, Philip; Weston, Nicholas J.; Hand, Duncan P.

    Additive manufacturing (AM) offers the possibility of creating a complex free form object as a single element, which is not possible using traditional mechanical machining. Unfortunately the typically rough surface finish of additively manufactured parts is unsuitable for many applications. As a result AM parts must be post-processed; typically mechanically machined and/or and polished using either chemical or mechanical techniques (both of which have their limitations). Laser based polishing is based on remelting of a very thin surface layer and it offers potential as a highly repeatable, higher speed process capable of selective area polishing, and without any waste problems (no abrasives or liquids). In this paper an in-depth investigation of CW laser polishing of titanium and cobalt chrome AM elements is presented. The impact of different scanning strategies, laser parameters and initial surface condition on the achieved surface finish is evaluated.

  18. Water Surface Turbulance and Internal Waves, Norfolk, VA, USA

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Norfolk and the mouth of the Chesapeake Bay, VA, (37.5N, 75.5W) was exposed in sunglint conditions to emphasizes water surface patterns. Outgoing tides from the bay generate considerable turbulence as they encounter coastal ocean currents and can be observed as differences in the reflective properties of the water surface. Smooth flowing water has high reflectivity. Turbulent water has a rough surface and low reflectance. Ship wakes can also be seen.

  19. Olefin Metathesis Reaction in Water and in Air Improved by Supramolecular Additives.

    PubMed

    Tomasek, Jasmine; Seßler, Miriam; Gröger, Harald; Schatz, Jürgen

    2015-10-21

    A range of water-immiscible commercially available Grubbs-type precatalysts can be used in ring-closing olefin metathesis reaction in high yields. The synthetic transformation is possible in pure water under ambient conditions. Sulfocalixarenes can help to boost the reactivity of the metathesis reaction by catalyst activation, improved mass transfer, and solubility of reactants in the aqueous reaction media. Additionally, the use of supramolecular additives allows lower catalyst loadings, but still high activity in pure water under aerobic conditions.

  20. Water formation by surface O3 hydrogenation.

    PubMed

    Romanzin, C; Ioppolo, S; Cuppen, H M; van Dishoeck, E F; Linnartz, H

    2011-02-28

    Three solid state formation routes have been proposed in the past to explain the observed abundance of water in space: the hydrogenation reaction channels of atomic oxygen (O + H), molecular oxygen (O(2) + H), and ozone (O(3) + H). New data are presented here for the third scheme with a focus on the reactions O(3) + H, OH + H and OH + H(2), which were difficult to quantify in previous studies. A comprehensive set of H/D-atom addition experiments is presented for astronomically relevant temperatures. Starting from the hydrogenation/deuteration of solid O(3) ice, we find experimental evidence for H(2)O/D(2)O (and H(2)O(2)/D(2)O(2)) ice formation using reflection absorption infrared spectroscopy. The temperature and H/D-atom flux dependence are studied and this provides information on the mobility of ozone within the ice and possible isotope effects in the reaction scheme. The experiments show that the O(3) + H channel takes place through stages that interact with the O and O(2) hydrogenation reaction schemes. It is also found that the reaction OH + H(2) (OH + H), as an intermediate step, plays a prominent (less efficient) role. The main conclusion is that solid O(3) hydrogenation offers a potential reaction channel for the formation of water in space. Moreover, the nondetection of solid ozone in dense molecular clouds is consistent with the astrophysical picture in which O(3) + H is an efficient process under interstellar conditions.

  1. Room temperature water splitting at the surface of magnetite.

    PubMed

    Parkinson, Gareth S; Novotný, Zbyněk; Jacobson, Peter; Schmid, Michael; Diebold, Ulrike

    2011-08-17

    An array of surface science measurements has revealed novel water adsorption behavior at the Fe(3)O(4)(001) surface. Following room temperature exposure to water, a low coverage of hydrogen atoms is observed, with no associated water hydroxyl group. Mild annealing of the hydrogenated surface leads to desorption of water via abstraction of surface oxygen atoms, leading to a reduction of the surface. These results point to an irreversible splitting of the water molecule. The observed phenomena are discussed in the context of recent DFT calculations (Mulakaluri, N.; Pentcheva, R.; Scheffler, M. J. Phys. Chem. C 2010, 114, 11148), which show that the Jahn-Teller distorted surface isolates adsorbed H in a geometry that could kinetically hinder recombinative desorption. In contrast, the adsorption geometry facilitates interaction between water hydroxyl species, which are concluded to leave the surface following a reactive desorption process, possibly via the creation of O(2).

  2. Strain-related variation in the persistence of influenza A virus in three types of water: distilled water, filtered surface water, and intact surface water

    PubMed Central

    2013-01-01

    Background The persistence of influenza A (IA) virus in aquatic habitats has been demonstrated to be a determinant for virus transmission dynamics in wild duck populations. In this study, we investigated virus strain-related variation in persistence in water for nine wild duck isolated IA viruses of three subtypes (H3N8, H4N6, and H8N4). Results We experimentally estimated the loss of infectivity over time in three different types of water: distilled, filtered surface water, and intact surface water. All viruses persisted longest in distilled water followed by filtered surface water with markedly reduced durations of persistence observed in the intact surface water. Strain-related variations were observed in distilled and filtered surface water but limited variation was observed in the intact surface water. Conclusions Our findings suggest that the role of surface water for long-term (between years) maintenance of AI viruses in the environment may be limited, and suggest that the physico-chemical characteristics of water, as well as microorganisms, may be of strong importance. Results also indicate that the extent of strain-related variation observed in distilled water may overestimate persistence abilities for IA viruses in the wild and supports the need to develop experiments that account for these effects to assess subtype, genotype, as well as spatial and temporal variation in the persistence of IA viruses in aquatic habitats. PMID:23289857

  3. Macro-invertebrate decline in surface water polluted with imidacloprid.

    PubMed

    Van Dijk, Tessa C; Van Staalduinen, Marja A; Van der Sluijs, Jeroen P

    2013-01-01

    Imidacloprid is one of the most widely used insecticides in the world. Its concentration in surface water exceeds the water quality norms in many parts of the Netherlands. Several studies have demonstrated harmful effects of this neonicotinoid to a wide range of non-target species. Therefore we expected that surface water pollution with imidacloprid would negatively impact aquatic ecosystems. Availability of extensive monitoring data on the abundance of aquatic macro-invertebrate species, and on imidacloprid concentrations in surface water in the Netherlands enabled us to test this hypothesis. Our regression analysis showed a significant negative relationship (P<0.001) between macro-invertebrate abundance and imidacloprid concentration for all species pooled. A significant negative relationship was also found for the orders Amphipoda, Basommatophora, Diptera, Ephemeroptera and Isopoda, and for several species separately. The order Odonata had a negative relationship very close to the significance threshold of 0.05 (P = 0.051). However, in accordance with previous research, a positive relationship was found for the order Actinedida. We used the monitoring field data to test whether the existing three water quality norms for imidacloprid in the Netherlands are protective in real conditions. Our data show that macrofauna abundance drops sharply between 13 and 67 ng l(-1). For aquatic ecosystem protection, two of the norms are not protective at all while the strictest norm of 13 ng l(-1) (MTR) seems somewhat protective. In addition to the existing experimental evidence on the negative effects of imidacloprid on invertebrate life, our study, based on data from large-scale field monitoring during multiple years, shows that serious concern about the far-reaching consequences of the abundant use of imidacloprid for aquatic ecosystems is justified.

  4. Macro-Invertebrate Decline in Surface Water Polluted with Imidacloprid

    PubMed Central

    Van Dijk, Tessa C.; Van Staalduinen, Marja A.; Van der Sluijs, Jeroen P.

    2013-01-01

    Imidacloprid is one of the most widely used insecticides in the world. Its concentration in surface water exceeds the water quality norms in many parts of the Netherlands. Several studies have demonstrated harmful effects of this neonicotinoid to a wide range of non-target species. Therefore we expected that surface water pollution with imidacloprid would negatively impact aquatic ecosystems. Availability of extensive monitoring data on the abundance of aquatic macro-invertebrate species, and on imidacloprid concentrations in surface water in the Netherlands enabled us to test this hypothesis. Our regression analysis showed a significant negative relationship (P<0.001) between macro-invertebrate abundance and imidacloprid concentration for all species pooled. A significant negative relationship was also found for the orders Amphipoda, Basommatophora, Diptera, Ephemeroptera and Isopoda, and for several species separately. The order Odonata had a negative relationship very close to the significance threshold of 0.05 (P = 0.051). However, in accordance with previous research, a positive relationship was found for the order Actinedida. We used the monitoring field data to test whether the existing three water quality norms for imidacloprid in the Netherlands are protective in real conditions. Our data show that macrofauna abundance drops sharply between 13 and 67 ng l−1. For aquatic ecosystem protection, two of the norms are not protective at all while the strictest norm of 13 ng l−1 (MTR) seems somewhat protective. In addition to the existing experimental evidence on the negative effects of imidacloprid on invertebrate life, our study, based on data from large-scale field monitoring during multiple years, shows that serious concern about the far-reaching consequences of the abundant use of imidacloprid for aquatic ecosystems is justified. PMID:23650513

  5. 40 CFR 258.27 - Surface water requirements.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... the discharge of a nonpoint source of pollution to waters of the United States, including wetlands... 40 Protection of Environment 26 2013-07-01 2013-07-01 false Surface water requirements. 258.27... FOR MUNICIPAL SOLID WASTE LANDFILLS Operating Criteria § 258.27 Surface water requirements....

  6. 40 CFR 258.27 - Surface water requirements.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... the discharge of a nonpoint source of pollution to waters of the United States, including wetlands... 40 Protection of Environment 26 2012-07-01 2011-07-01 true Surface water requirements. 258.27... FOR MUNICIPAL SOLID WASTE LANDFILLS Operating Criteria § 258.27 Surface water requirements....

  7. 40 CFR 257.3-3 - Surface water.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Water Act, as amended, 33 U.S.C. 1251 et seq., and implementing regulations, specifically 33 CFR part... 40 Protection of Environment 25 2014-07-01 2014-07-01 false Surface water. 257.3-3 Section 257.3-3... and Practices § 257.3-3 Surface water. (a) For purposes of section 4004(a) of the Act, a...

  8. 40 CFR 257.3-3 - Surface water.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Water Act, as amended, 33 U.S.C. 1251 et seq., and implementing regulations, specifically 33 CFR part... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Surface water. 257.3-3 Section 257.3-3... and Practices § 257.3-3 Surface water. (a) For purposes of section 4004(a) of the Act, a...

  9. 40 CFR 258.27 - Surface water requirements.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 25 2014-07-01 2014-07-01 false Surface water requirements. 258.27... FOR MUNICIPAL SOLID WASTE LANDFILLS Operating Criteria § 258.27 Surface water requirements. MSWLF... wetlands, that violates any requirements of the Clean Water Act, including, but not limited to,...

  10. 40 CFR 257.3-3 - Surface water.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Water Act, as amended, 33 U.S.C. 1251 et seq., and implementing regulations, specifically 33 CFR part... 40 Protection of Environment 25 2011-07-01 2011-07-01 false Surface water. 257.3-3 Section 257.3-3... and Practices § 257.3-3 Surface water. (a) For purposes of section 4004(a) of the Act, a...

  11. 40 CFR 257.3-3 - Surface water.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Water Act, as amended, 33 U.S.C. 1251 et seq., and implementing regulations, specifically 33 CFR part... 40 Protection of Environment 26 2012-07-01 2011-07-01 true Surface water. 257.3-3 Section 257.3-3... and Practices § 257.3-3 Surface water. (a) For purposes of section 4004(a) of the Act, a...

  12. 40 CFR 257.3-3 - Surface water.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Water Act, as amended, 33 U.S.C. 1251 et seq., and implementing regulations, specifically 33 CFR part... 40 Protection of Environment 26 2013-07-01 2013-07-01 false Surface water. 257.3-3 Section 257.3-3... and Practices § 257.3-3 Surface water. (a) For purposes of section 4004(a) of the Act, a...

  13. 40 CFR 258.27 - Surface water requirements.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 25 2011-07-01 2011-07-01 false Surface water requirements. 258.27... FOR MUNICIPAL SOLID WASTE LANDFILLS Operating Criteria § 258.27 Surface water requirements. MSWLF... wetlands, that violates any requirements of the Clean Water Act, including, but not limited to,...

  14. Adsorption structure of water molecules on the Be(0001) surface

    SciTech Connect

    Yang, Yu; Li, Yanfang; Wang, Shuangxi; Zhang, Ping

    2014-06-07

    By using density functional theory calculations, we systematically investigate the adsorption of water molecules at different coverages on the Be(0001) surface. The coverage dependence of the prototype water structures and energetics for water adlayer growth are systematically studied. The structures, energetics, and electronic properties are calculated and compared with other available studies. Through our systematic investigations, we find that water molecules form clusters or chains on the Be(0001) surface at low coverages. When increasing the water coverage, water molecules tend to form a 2 × 2 hexagonal network on the Be(0001) surface.

  15. Enthalpic Breakdown of Water Structure on Protein Active-Site Surfaces.

    PubMed

    Haider, Kamran; Wickstrom, Lauren; Ramsey, Steven; Gilson, Michael K; Kurtzman, Tom

    2016-09-01

    The principles underlying water reorganization around simple nonpolar solutes are well understood and provide the framework for the classical hydrophobic effect, whereby water molecules structure themselves around solutes so that they maintain favorable energetic contacts with both the solute and the other water molecules. However, for certain solute surface topographies, water molecules, due to their geometry and size, are unable to simultaneously maintain favorable energetic contacts with both the surface and neighboring water molecules. In this study, we analyze the solvation of ligand-binding sites for six structurally diverse proteins using hydration site analysis and measures of local water structure, in order to identify surfaces at which water molecules are unable to structure themselves in a way that maintains favorable enthalpy relative to bulk water. These surfaces are characterized by a high degree of enclosure, weak solute-water interactions, and surface constraints that induce unfavorable pair interactions between neighboring water molecules. Additionally, we find that the solvation of charged side chains in an active site generally results in favorable enthalpy but can also lead to pair interactions between neighboring water molecules that are significantly unfavorable relative to bulk water. We find that frustrated local structure can occur not only in apolar and weakly polar pockets, where overall enthalpy tends to be unfavorable, but also in charged pockets, where overall water enthalpy tends to be favorable. The characterization of local water structure in these terms may prove useful for evaluating the displacement of water from diverse protein active-site environments.

  16. Sustainability of global groundwater and surface water use: past reconstruction and future projections

    NASA Astrophysics Data System (ADS)

    Wada, Y.; Bierkens, M. F.

    2014-12-01

    Overuse of surface water and an increasing reliance on nonrenewable groundwater resources have been reported over various regions of the world, casting significant doubt on the sustainable water supply and food production met by irrigation. To assess the limitations of global water resources, numerous indicators have been developed, but they rarely consider nonrenewable water use. In addition, surface water over-abstraction is rarely assessed in the context of human and environmental water needs. Here, we perform a transient assessment of global groundwater and surface water use over the historical period 1960-2010 as well as the future projections of 2011-2099, using a newly developed indicator: the Blue Water Sustainability Index (BlWSI). The BlWSI incorporates both nonrenewable groundwater use and nonsustainable water use that compromises environmental flow requirements. Our results reveal an increasing trend of water consumed from nonsustainable surface water and groundwater resources over the historical period (~30%), and this increase is projected to continue further towards the end of this century (~40%). The global amount of nonsustainable water consumption has been increasing especially since the late 1990s, despite a wetter climate and increasing water availability during this period. The BlWSI is the first tool suitable for consistently evaluating the renewability and degradation of surface water and groundwater resources as a result of human water over-abstraction.

  17. First-principles study of water desorption from montmorillonite surface.

    PubMed

    Zhang, Yao; Meng, Yingfeng; Liu, Houbin; Yang, Mingli

    2016-05-01

    Knowledge about water desorption is important to give a full picture of water diffusion in montmorillonites (MMT), which is a driving factor in MMT swelling. The desorption paths and energetics of water molecules from the surface of MMT with trapped Li(+), Na(+) or K(+) counterions were studied using periodic density functional theory calculations. Two paths--surface and vacuum desorption--were designed for water desorption starting from a stationary structure in which water bonds with both the counterion and the MMT surface. Surface desorption is energetically more favorable than vacuum desorption due to water-surface hydrogen bonds that help stabilize the intermediate structure of water released from the counterion. The energy barriers of water desorption are in the order of Li(+) > Na(+) > K(+), which can be attributed to the short ionic radius of Li(+), which favors strong binding with the water molecule. The temperature dependence of water adsorption and desorption rates were compared based on the computed activation energies. Our calculations reveal that the water desorption on the MMT surface has a different mechanism from water adsorption, which results from surface effects favoring stabilization of water conformers during the desorption process. PMID:27083565

  18. Effects of water addition on soil arthropods and soil characteristics in a precipitation-limited environment

    NASA Astrophysics Data System (ADS)

    Chikoski, Jennifer M.; Ferguson, Steven H.; Meyer, Lense

    2006-09-01

    We investigated the effect of water addition and season on soil arthropod abundance and soil characteristics (%C, %N, C:N, moisture, pH). The experimental design consisted of 24 groups of five boxes distributed within a small aspen stand in Saskatchewan, Canada. The boxes depressed the soil to create a habitat with suitable microclimate for soil arthropods, and by overturning boxes we counted soil arthropods during weekly surveys from April to September 1999. Soil samples were collected at two-month intervals and water was added once per week to half of the plots. Of the eleven recognizable taxonomic units identified, only mites (Acari) and springtails (Collembola) responded to water addition by increasing abundance, whereas ants decreased in abundance with water addition. During summer, springtail numbers increased with water addition, whereas pH was a stronger determinant of mite abundance. In autumn, springtails were positively correlated with water and negatively correlated with mites, whereas mite abundance was negatively correlated with increasing C:N ratio, positively correlated to water addition, and negatively correlated with springtail abundance. Although both mite and springtail numbers decreased in autumn with a decrease in soil moisture, mites became more abundant than springtails suggesting a predator-prey (mite-springtail) relationship. Water had a significant effect on both springtails and mites in summer and autumn supporting the assertion that prairie soil communities are water limited.

  19. Effect of Surface-active Additives on Physical Properties of Slurries of Vapor-process Magnesium

    NASA Technical Reports Server (NTRS)

    Pinns, Murray L

    1955-01-01

    The presence of 3 to 5 percent surface-active additive gave the lowest Brookfield apparent viscosity, plastic viscosity, and yield value that were obtained for slurry fuels containing approximately 50 percent vapor-process magnesium in JP-1 fuel. The slurries settled little and were easily remixed. A polyoxyethylene dodecyl alcohol was the most effective of 13 additives tested in reducing the Brookfield apparent viscosity and the yield value of the slurry. The seven most effective additives all had a hydroxyl group plus an ester or polyoxethylene group in the molecule. The densities of some of the slurries were measured.

  20. Soy Protein Isolate As Fluid Loss Additive in Bentonite-Water-Based Drilling Fluids.

    PubMed

    Li, Mei-Chun; Wu, Qinglin; Song, Kunlin; Lee, Sunyoung; Jin, Chunde; Ren, Suxia; Lei, Tingzhou

    2015-11-11

    Wellbore instability and formation collapse caused by lost circulation are vital issues during well excavation in the oil industry. This study reports the novel utilization of soy protein isolate (SPI) as fluid loss additive in bentonite-water based drilling fluids (BT-WDFs) and describes how its particle size and concentration influence on the filtration property of SPI/BT-WDFs. It was found that high pressure homogenization (HPH)-treated SPI had superior filtration property over that of native SPI due to the improved ability for the plugging pore throat. HPH treatment also caused a significant change in the surface characteristic of SPI, leading to a considerable surface interaction with BT in aqueous solution. The concentration of SPI had a significant impact on the dispersion state of SPI/BT mixtures in aquesous solution. At low SPI concentrations, strong aggregations were created, resulting in the formation of thick, loose, high-porosity and high-permeability filter cakes and high fluid loss. At high SPI concentrations, intercatlated/exfoliated structures were generated, resulting in the formation of thin, compact, low-porosity and low-permeability filter cakes and low fluid loss. The SPI/BT-WDFs exhibited superior filtration property than pure BT-WDFs at the same solid concentraion, demonstrating the potential utilization of SPI as an effective, renewable, and biodegradable fluid loss reducer in well excavation applications. PMID:26492498

  1. Soy Protein Isolate As Fluid Loss Additive in Bentonite-Water-Based Drilling Fluids.

    PubMed

    Li, Mei-Chun; Wu, Qinglin; Song, Kunlin; Lee, Sunyoung; Jin, Chunde; Ren, Suxia; Lei, Tingzhou

    2015-11-11

    Wellbore instability and formation collapse caused by lost circulation are vital issues during well excavation in the oil industry. This study reports the novel utilization of soy protein isolate (SPI) as fluid loss additive in bentonite-water based drilling fluids (BT-WDFs) and describes how its particle size and concentration influence on the filtration property of SPI/BT-WDFs. It was found that high pressure homogenization (HPH)-treated SPI had superior filtration property over that of native SPI due to the improved ability for the plugging pore throat. HPH treatment also caused a significant change in the surface characteristic of SPI, leading to a considerable surface interaction with BT in aqueous solution. The concentration of SPI had a significant impact on the dispersion state of SPI/BT mixtures in aquesous solution. At low SPI concentrations, strong aggregations were created, resulting in the formation of thick, loose, high-porosity and high-permeability filter cakes and high fluid loss. At high SPI concentrations, intercatlated/exfoliated structures were generated, resulting in the formation of thin, compact, low-porosity and low-permeability filter cakes and low fluid loss. The SPI/BT-WDFs exhibited superior filtration property than pure BT-WDFs at the same solid concentraion, demonstrating the potential utilization of SPI as an effective, renewable, and biodegradable fluid loss reducer in well excavation applications.

  2. Water Resources Data, Florida, Water Year 2003 Volume 2A: South Florida Surface Water

    USGS Publications Warehouse

    Price, C.; Woolverton, J.; Overton, K.

    2004-01-01

    Water resources data for 2003 water year in Florida consists of continuous or daily discharge for 385 streams, periodic discharge for 13 streams, continuous or daily stage for 255 streams, periodic stage for 13 stream, peak discharge for 36 streams, and peak stage for 36 streams, continuous or daily elevations for 13 lakes, periodic elevations for 46 lakes, continuous ground-water levels for 441 wells, periodic ground-water levels for 1227 wells, quality of water data for 133 surface-water sites, and 308 wells. The data for South Florida included continuous or daily discharge for 72 streams, continuous or daily stage for 50 streams, no peak stage discharge for streams, 1 continuous elevation for lake, continuous ground-water levels for 237 wells, periodic ground-water levels for 248 wells, water quality for 25 surface-water sites, and 161 wells. These data represent the National Water Data System records collected by the U.S. Geological Survey and cooperation with local, state, and federal agencies in Florida.

  3. Water resources data-Florida water year 2004volume 2A: south Florida surface water

    USGS Publications Warehouse

    Price, C.; Woolverton, J.; Overton, K.

    2005-01-01

    Water resources data for 2004 water year in Florida consists of continuous or daily discharge for 405 streams, periodic discharge for 12 streams, continuous or daily stage for 159 streams, periodic stage for 19 stream, peak discharge for 30 streams, and peak stage for 30 streams, continuous or daily elevations for 14 lakes, periodic elevations for 23 lakes, continuous ground-water levels for 408 wells, periodic ground-water levels for 1188 wells, quality of water data for 140 surface-water sites, and 240 wells. The data for South Florida included continuous or daily discharge for 86 streams, continuous or daily stage for 54 streams, no peak stage discharge for streams, 1 continuous elevation for lake, continuous ground-water levels for 257 wells, periodic ground-water levels for 226 wells, water quality for 39 surface-water sites, and 149 wells. These data represent the National Water Data System records collected by the U.S. Geological Survey and cooperating local, State, and Federal agencies in Florida.

  4. Water Resources Data, Florida, Water Year 2001, Volume 2A. South Florida Surface Water

    USGS Publications Warehouse

    Price, C.; Woolverton, J.; Overton, K.

    2002-01-01

    Water resources data for 2001 water year in Florida consists of continuous or daily discharge for 404 streams, periodic discharge for 15 streams, continuous or daily stage for 154 streams, periodic stage for 12 stream, peak discharge for 37 streams, and peak stage for 37 streams, continuous or daily elevations for 12 lakes, periodic elevations for 50 lakes, continuous ground-water levels for 426 wells, periodic ground-water levels for 1251 wells, quality of water data for 112 surface-water sites, and 235 wells. The data for South Florida included continuous or daily discharge for 89 streams, continuous or daily stage for 64 streams, no peak stage discharge for streams, 1 continuous elevation for lake, continuous ground-water levels for 244 wells, periodic ground-water levels for 255 wells, water quality for 32 surface-water sites, and 166 wells. The data represent the National Water Data System records collected by the U.S. Geological Survey and cooperation with local, state, and federal agencies in Florida.

  5. Water resources data, Florida, water year 2005. Volume 2A: south Florida surface water

    USGS Publications Warehouse

    Price, C.; Overton, K.

    2006-01-01

    Water resources data for 2005 water year in Florida consists of continuous or daily discharge for 429 streams, periodic discharge for 9 streams, continuous or daily stage for 218 streams, periodic stage for 5 stream, peak discharge for 28 streams, and peak stage for 28 streams, continuous or daily elevations for 15 lakes, periodic elevations for 23 lakes, continuous ground-water levels for 401 wells, periodic ground-water levels for 1,098 wells, quality of water data for 211 surface-water sites, and 208 wells. The data for South Florida included continuous or daily discharge for 91 streams, continuous or daily stage for 62 streams, no peak stage discharge for streams, 1 continuous elevation for lake, continuous ground-water levels for 248 wells, periodic ground-water levels for 187 wells, water quality for 54 surface-water sites, and 121 wells. These data represent the National Water Data System records collected by the U.S. Geological Survey and cooperating local, State, and Federal agencies in Florida.

  6. Water Resources Data, Florida, Water Year 2002, Volume 2A. South Florida Surface Water

    USGS Publications Warehouse

    Price, C.; Woolverton, J.; Overton, K.

    2003-01-01

    Water resources data for 2002 water year in Florida consists of continuous or daily discharge for 392 streams, periodic discharge for 15 streams, continuous or daily stage for 191 streams, periodic stage for 13 stream, peak discharge for 33 streams, and peak stage for 33 streams, continuous or daily elevations for 14 lakes, periodic elevations for 49 lakes, continuous ground-water levels for 418 wells, periodic ground-water levels for 1287 wells, quality of water data for 116 surface-water sites, and 291 wells. The data for South Florida included continuous or daily discharge for 71 streams, continuous or daily stage for 49 streams, no peak stage discharge for streams, 1 continuous elevation for lake, continuous ground-water levels for 238 wells, periodic ground-water levels for 260 wells, water quality for 24 surface-water sites, and 159 wells. The data represent the National Water Data System records collected by the U.S. Geological Survey and cooperation with local, state, and federal agencies in Florida.

  7. Water resources data for Florida water year 2004volume 1A. northeast Florida surface water

    USGS Publications Warehouse

    Herrett, Thomas A.; Hess, Glen W.; House, Jon G.; Ruppert, Gregory P.; Courts, Mary-Lorraine

    2005-01-01

    Water resources data for the 2004 water year in Florida consist of continuous or daily discharge for 405 streams, periodic discharge for 12 streams, continuous or daily stage for 159 streams, periodic stage for 19 streams, peak stage and discharge for 30 streams; continuous or daily elevations for 14 lakes, periodic elevations for 23 lakes; continuous ground-water levels for 408 wells, periodic ground-water levels for 1,157 wells; quality-of-water data for 140 surface-water sites and 239 wells. The data for northeast Florida include continuous or daily discharge for 140 streams, periodic discharge for 4 streams, continuous or daily stage for 58 streams, periodic stage for 3 streams; peak stage and discharge for 0 streams; continuous or daily elevations for 10 lakes, periodic elevations for 20 lakes; continuous ground water levels for 50 wells, periodic ground-water levels for 522 wells; quality-of-water data for 40 surface-water sites and 66 wells. These data represent the National Water Data System records collected by the U.S. Geological Survey and cooperating local, State and Federal agencies in Florida.

  8. Plant nitrogen uptake drives responses of productivity to nitrogen and water addition in a grassland

    PubMed Central

    Lü, Xiao-Tao; Dijkstra, Feike A.; Kong, De-Liang; Wang, Zheng-Wen; Han, Xing-Guo

    2014-01-01

    Increased atmospheric nitrogen (N) deposition and altered precipitation regimes have profound impacts on ecosystem functioning in semiarid grasslands. The interactions between those two factors remain largely unknown. A field experiment with N and water additions was conducted in a semiarid grassland in northern China. We examined the responses of aboveground net primary production (ANPP) and plant N use during two contrasting hydrological growing seasons. Nitrogen addition had no impact on ANPP, which may be accounted for by the offset between enhanced plant N uptake and decreased plant nitrogen use efficiency (NUE). Water addition significantly enhanced ANPP, which was largely due to enhanced plant aboveground N uptake. Nitrogen and water additions significantly interacted to affect ANPP, plant N uptake and N concentrations at the community level. Our observations highlight the important role of plant N uptake and use in mediating the effects of N and water addition on ANPP. PMID:24769508

  9. Investigation of natural biofilms formed during the production of drinking water from surface water embankment filtration.

    PubMed

    Emtiazi, Farahnaz; Schwartz, Thomas; Marten, Silke Mareike; Krolla-Sidenstein, Peter; Obst, Ursula

    2004-03-01

    Populations of bacteria in biofilms from different sites of a drinking water production system were analysed. Polymerase chain reaction (PCR) and denaturing gradient gel electrophoresis (DGGE) analyses revealed changing DNA band patterns, suggesting a population shift during bank filtration and processing at the waterworks. In addition, common DNA bands that were attributed to ubiquitous bacteria were found. Biofilms even developed directly after UV disinfection (1-2m distance). Their DNA band patterns only partly agreed with those of the biofilms from the downstream distribution system. Opportunistic pathogenic bacteria in biofilms were analysed using PCR and Southern blot hybridisation (SBH). Surface water appeared to have a direct influence on the composition of biofilms in the drinking water distribution system. In spite of preceding filtration and UV disinfection, opportunistic pathogens such as atypical mycobacteria and Legionella spp. were found in biofilms of drinking water, and Pseudomonas aeruginosa was detected sporadically. Enterococci were not found in any biofilm. Bacterial cell counts in the biofilms from surface water to drinking water dropped significantly, and esterase and alanine-aminopeptidase activity decreased. beta-glucosidase activity was not found in the biofilms. Contrary to the results for planktonic bacteria, inhibitory effects were not observed in biofilms. This suggested an increased tolerance of biofilm bacteria against toxic compounds.

  10. Water resources data, North Carolina, water year 2005. Volume 1: Surface-water records

    USGS Publications Warehouse

    Walters, D.A.; Robinson, J.B.; Barker, R.G.

    2006-01-01

    Water-resources data for the 2005 water year for North Carolina consist of records of stage, discharge, and water quality for streams; stage and contents for lakes and reservoirs; precipitation; and ground-water levels and water quality of ground water. Volume 1 contains discharge records for 215 gaging stations; stage and contents for 60 lakes and reservoirs; stage only records for 25 gaging stations; elevations for 10 stations; water quality for 35 gaging stations and continuous water quality for 19 sites; and continuous precipitation at 127 sites. Volume 2 contains ground-water-level data from 180 observation wells, ground-water-quality data from 36 wells, continuous water quality for 3 sites and continuous precipitation at 4 sites. Additional water data were collected at 53 sites not involved in the systematic data-collection program, and are published as miscellaneous measurements in Volume 1. The collection of water-resources data in North Carolina is a part of the National Water-Data System operated by the U.S. Geological Survey in cooperation with State, municipal, and Federal agencies.

  11. Water resources data, North Carolina, water year 2004. Volume 1: Surface-water records

    USGS Publications Warehouse

    Walters, D.A.; Robinson, J.B.; Barker, R.G.

    2005-01-01

    Water-resources data for the 2004 water year for North Carolina consist of records of stage, discharge, water quality for streams; stage and contents for lakes and reservoirs; precipitation; and ground-water levels and water quality of ground water. Volume 1 contains discharge records for 217 gaging stations; stage and contents for 58 lakes and reservoirs; stage only records for 22 gaging stations; elevations for 9 stations; water quality for 39 gaging stations and 5 miscellaneous sites, and continuous water quality for 35 sites; and continuous precipitation at 127 sites. Volume 2 contains ground-water-level data from 161 observation wells, ground-water-quality data from 38 wells, continuous water quality for 7 sites and continuous precipitation at 7 sites. Additional water data were collected at 51 sites not involved in the systematic data-collection program, and are published as miscellaneous measurements in Volume 1. The collection of water-resources data in North Carolina is a part of the National Water-Data System operated by the U.S. Geological Survey in cooperation with State, municipal, and Federal agencies.

  12. Microscopic origin of the surface tension anomaly of water.

    PubMed

    Sega, Marcello; Horvai, George; Jedlovszky, Pál

    2014-03-25

    We investigate the hydrogen bonding percolation threshold of water molecules at the surface of the liquid-vapor interface. We show that the percolation temperature agrees within statistical accuracy with the high-temperature inflection point of the water surface tension. We associate the origin of this surface tension anomaly of water with the sudden breakup of the hydrogen-bonding network in the interfacial molecular layer.

  13. Water Resources Data: New Jersey, Water Year 1998, Volume 1, Surface-Water Data

    USGS Publications Warehouse

    Reed, T.J.; Centinaro, G.L.; Dudek, J.F.; Corcino, V.; Stekroadt, G.C.; McTigure, R.C.

    1999-01-01

    This volume of the annual hydrologic data report of New Jersey is one of a series of annual reports that document hydrologic data gathered from the U.S. Geological Survey's surface- and ground-water data-collection networks in each State, Puerto Rico, and the Trust Territories. These records of streamflow, ground-water levels, and water quality provide the hydrologic information needed by state, local and federal agencies, and the private sector for developing and managing our Nation's land and water resources.

  14. High prevalence of enteric viruses in untreated individual drinking water sources and surface water in Slovenia.

    PubMed

    Steyer, Andrej; Torkar, Karmen Godič; Gutiérrez-Aguirre, Ion; Poljšak-Prijatelj, Mateja

    2011-09-01

    Waterborne infections have been shown to be important in outbreaks of gastroenteritis throughout the world. Although improved sanitary conditions are being progressively applied, fecal contaminations remain an emerging problem also in developed countries. The aim of our study was to investigate the prevalence of fecal contaminated water sources in Slovenia, including surface waters and groundwater sources throughout the country. In total, 152 water samples were investigated, of which 72 samples represents groundwater from individual wells, 17 samples from public collection supplies and 63 samples from surface stream waters. Two liters of untreated water samples were collected and concentrated by the adsorption/elution technique with positively charged filters followed by an additional ultracentrifugation step. Group A rotaviruses, noroviruses (genogroups I and II) and astroviruses were detected with real-time RT-PCR method in 69 (45.4%) out of 152 samples collected, of which 31/89 (34.8%) drinking water and 38/63 (60.3%) surface water samples were positive for at least one virus tested. In 30.3% of drinking water samples group A rotaviruses were detected (27/89), followed by noroviruses GI (2.2%; 2/89) and astroviruses (2.2%; 2/89). In drinking groundwater samples group A rotaviruses were detected in 27 out of 72 tested samples (37.5%), genogroup I noroviruses in two (2.8%), and human astroviruses in one (1.4%) samples. In surface water samples norovirus genogroup GII was the most frequently detected (41.3%; 26/63), followed by norovirus GI (33.3%; 21/63), human astrovirus (27.0%; 17/63) and group A rotavirus (17.5%; 11/63). Our study demonstrates relatively high percentage of groundwater contamination in Slovenia and, suggests that raw groundwater used as individual drinking water supply may constitute a possible source of enteric virus infections. In the future, testing for enteric viruses should be applied for drinking water sources in waterborne outbreaks.

  15. Water resources data, North Carolina, water year 2002. Volume 1B: Surface-water records

    USGS Publications Warehouse

    Ragland, B.C.; Barker, R.G.; Robinson, J.B.

    2003-01-01

    Water-resources data for the 2002 water year for North Carolina consist of records of stage, discharge, water quality for streams; stage and contents for lakes and reservoirs; precipitation; and ground-water levels and water quality of ground water. Volume 1 contains discharge records for 211 gaging stations; stage and contents for 62 lakes and reservoirs; stage for 20 gaging stations; water quality for 52 gaging stations and 7 miscellaneous sites, and continuous water quality for 30 sites; and continuous precipitation at 109 sites. Volume 2 contains ground-water-level data from 143 observation wells and ground-water-quality data from 72 wells. Additional water data were collected at 85 sites not involved in the systematic data-collection program, and are published as miscellaneous measurements in Volume 1. The collection of water-resources data in North Carolina is a part of the National Water-Data System operated by the U.S. Geological Survey in cooperation with State, municipal, and Federal agencies.

  16. Layered Double Hydroxide Nanoplatelets with Excellent Tribological Properties under High Contact Pressure as Water-Based Lubricant Additives

    PubMed Central

    Wang, Hongdong; Liu, Yuhong; Chen, Zhe; Wu, Bibo; Xu, Sailong; Luo, Jianbin

    2016-01-01

    High efficient and sustainable utilization of water-based lubricant is essential for saving energy. In this paper, a kind of layered double hydroxide (LDH) nanoplatelets is synthesized and well dispersed in water due to the surface modification with oleylamine. The excellent tribological properties of the oleylamine-modified Ni-Al LDH (NiAl-LDH/OAm) nanoplatelets as water-based lubricant additives are evaluated by the tribological tests in an aqueous environment. The modified LDH nanoplatelets are found to not only reduce the friction but also enhance the wear resistance, compared with the water-based cutting fluid and lubricants containing other particle additives. By adding 0.5 wt% LDH nanoplatelets, under 1.5 GPa initial contact pressure, the friction coefficient, scar diameter, depth and width of the wear track dramatically decrease by 83.1%, 43.2%, 88.5% and 59.5%, respectively. It is considered that the sufficiently small size and the excellent dispersion of NiAl-LDH/OAm nanoplatelets in water are the key factors, so as to make them enter the contact area, form a lubricating film and prevent direct collision of asperity peaks. Our investigations demonstrate that the LDH nanoplatelet as a water-based lubricant additive has a great potential value in industrial application. PMID:26951794

  17. Layered Double Hydroxide Nanoplatelets with Excellent Tribological Properties under High Contact Pressure as Water-Based Lubricant Additives

    NASA Astrophysics Data System (ADS)

    Wang, Hongdong; Liu, Yuhong; Chen, Zhe; Wu, Bibo; Xu, Sailong; Luo, Jianbin

    2016-03-01

    High efficient and sustainable utilization of water-based lubricant is essential for saving energy. In this paper, a kind of layered double hydroxide (LDH) nanoplatelets is synthesized and well dispersed in water due to the surface modification with oleylamine. The excellent tribological properties of the oleylamine-modified Ni-Al LDH (NiAl-LDH/OAm) nanoplatelets as water-based lubricant additives are evaluated by the tribological tests in an aqueous environment. The modified LDH nanoplatelets are found to not only reduce the friction but also enhance the wear resistance, compared with the water-based cutting fluid and lubricants containing other particle additives. By adding 0.5 wt% LDH nanoplatelets, under 1.5 GPa initial contact pressure, the friction coefficient, scar diameter, depth and width of the wear track dramatically decrease by 83.1%, 43.2%, 88.5% and 59.5%, respectively. It is considered that the sufficiently small size and the excellent dispersion of NiAl-LDH/OAm nanoplatelets in water are the key factors, so as to make them enter the contact area, form a lubricating film and prevent direct collision of asperity peaks. Our investigations demonstrate that the LDH nanoplatelet as a water-based lubricant additive has a great potential value in industrial application.

  18. Layered Double Hydroxide Nanoplatelets with Excellent Tribological Properties under High Contact Pressure as Water-Based Lubricant Additives.

    PubMed

    Wang, Hongdong; Liu, Yuhong; Chen, Zhe; Wu, Bibo; Xu, Sailong; Luo, Jianbin

    2016-01-01

    High efficient and sustainable utilization of water-based lubricant is essential for saving energy. In this paper, a kind of layered double hydroxide (LDH) nanoplatelets is synthesized and well dispersed in water due to the surface modification with oleylamine. The excellent tribological properties of the oleylamine-modified Ni-Al LDH (NiAl-LDH/OAm) nanoplatelets as water-based lubricant additives are evaluated by the tribological tests in an aqueous environment. The modified LDH nanoplatelets are found to not only reduce the friction but also enhance the wear resistance, compared with the water-based cutting fluid and lubricants containing other particle additives. By adding 0.5 wt% LDH nanoplatelets, under 1.5 GPa initial contact pressure, the friction coefficient, scar diameter, depth and width of the wear track dramatically decrease by 83.1%, 43.2%, 88.5% and 59.5%, respectively. It is considered that the sufficiently small size and the excellent dispersion of NiAl-LDH/OAm nanoplatelets in water are the key factors, so as to make them enter the contact area, form a lubricating film and prevent direct collision of asperity peaks. Our investigations demonstrate that the LDH nanoplatelet as a water-based lubricant additive has a great potential value in industrial application. PMID:26951794

  19. Structure of water adsorbed on a mica surface

    SciTech Connect

    Park, Sung-Ho; Sposito, Garrison

    2002-01-29

    Monte Carlo simulations of hydration water on the mica (001) surface under ambient conditions revealed water molecules bound closely to the ditrigonal cavities in the surface, with a lateral distribution of approximately one per cavity, and water molecules interposed between K{sup +} counter ions in a layer situated about 2.5 {angstrom} from a surface O along a direction normal to the (001) plane. The calculated water O density profile was in quantitative agreement with recent X-ray reflectivity measurements indicating strong lateral ordering of the hydration water but liquid-like disorder otherwise.

  20. Improving water tolerance of Co3O4 by SnO2 addition for CO oxidation

    NASA Astrophysics Data System (ADS)

    Xu, Xianglan; Sun, Xiongfei; Han, Hong; Peng, Honggen; Liu, Wenming; Peng, Xing; Wang, Xiang; Yang, Xiangjie

    2015-11-01

    A series of Sn-modified Co3O4 catalysts with different Co/Sn molar ratios were prepared via co-precipitation method and characterized by N2-BET, XRD, H2-TPR, XPS and FTIR techniques. The addition of a small amount of Sn into Co3O4 has a mild influence on its CO oxidation activity, but promotes its water resistance evidently. The major reason is attributed to the effective suppressing of water adsorption on the catalyst surface by Sn addition, as testified by FTIR results. Co0.90Sn0.10, a catalyst with a Co/Sn molar ratio of 0.90/0.10, shows the potential to be used in some real emission control processes for CO oxidation due to its reasonable activity and evidently improved reaction stability in the presence of water vapour.

  1. Surface Tension: The Ways of Water.

    ERIC Educational Resources Information Center

    Donalson-Sams, Marilyn

    1988-01-01

    Describes activities which help students understand several basic scientific concepts regarding water. Outlines objectives, materials needed, procedures, and questions to ask about student observations. Investigations include working with the self-sealing property of water, talcum powder, paper clips, and making water wetter. (RT)

  2. Additive manufactured polymeric 3D scaffolds with tailored surface topography influence mesenchymal stromal cells activity.

    PubMed

    Neves, Sara C; Mota, Carlos; Longoni, Alessia; Barrias, Cristina C; Granja, Pedro L; Moroni, Lorenzo

    2016-06-01

    Additive manufactured three-dimensional (3D) scaffolds with tailored surface topography constitute a clear advantage in tissue regeneration strategies to steer cell behavior. 3D fibrous scaffolds of poly(ethylene oxide terephthalate)/poly(butylene terephthalate) block copolymer presenting different fiber surface features were successfully fabricated by additive manufacturing combined with wet-spinning, in a single step, without any post-processing. The optimization of the processing parameters, mainly driven by different solvent/non-solvent combinations, led to four distinct scaffold types, with average surface roughness values ranging from 0.071 ± 0.012 μm to 1.950 ± 0.553 μm, average pore sizes in the x- and y-axis between 351.1 ± 33.6 μm and 396.1 ± 32.3 μm, in the z-axis between 36.5 ± 5.3 μm and 70.7 ± 8.8 μm, average fiber diameters between 69.4 ± 6.1 μm and 99.0 ± 9.4 μm, and porosity values ranging from 60.2 ± 0.8% to 71.7 ± 2.6%. Human mesenchymal stromal cells (hMSCs) cultured on these scaffolds adhered, proliferated, and produced endogenous extracellular matrix. The effect of surface roughness and topography on hMSCs differentiation was more evident for cells seeded at lower density, where the percentage of cells in direct contact with the surface was higher compared to more densely seeded scaffolds. Under osteogenic conditions, lower surface roughness values (0.227 ± 0.035 μm) had a synergistic effect on hMSCs behavior, while chondrogenesis was favored on rougher surfaces (1.950 ± 0.553 μm). PMID:27219645

  3. Review of methods for assessing nonpoint-source contaminated ground-water discharge to surface water

    SciTech Connect

    Not Available

    1991-04-01

    The document provides an overview of selected methods that have been used for assessing nonpoint source contaminated ground water discharge to surface water. EPA undertook the project in response to the growing awareness that contaminated ground water discharge is a significant source of nonpoint source contaminant loading to surface water in many parts of the country.

  4. Water Condensation Kinetics on a Hydrophobic Surface

    NASA Astrophysics Data System (ADS)

    Linderoth, Trolle R.; Zhdanov, Vladimir P.; Kasemo, Bengt

    2003-04-01

    Employing thermal desorption spectroscopy, we show that the effective probability of water condensation at low water vapor pressure on an octane film is much below unity at 100 120K. This unusual finding is related to a small binding energy of H2O monomers on octane (≃0.08 eV), requiring the formation of critical water clusters for condensation to occur. This results in strong temperature and impingement-rate dependencies of the water condensation rate and a nonlinear uptake as a function of dose time. All these features are rationalized quantitatively by a kinetic model of water condensation.

  5. Effect of lubricant extreme-pressure additives on surface fatigue life of AISI 9310 spur gears

    NASA Technical Reports Server (NTRS)

    Scibbe, H. W.; Townsend, D. P.; Aron, P. R.

    1984-01-01

    Surface fatigue tests were conducted with AISI 9310 spur gears using a formulated synthetic tetraester oil (conforming to MIL-L-23699 specifications) as the lubricant containing either sulfur or phosphorus as the EP additive. Four groups of gears were tested. One group of gears tested without an additive in the lubricant acted as the reference oil. In the other three groups either a 0.1 wt % sulfur or phosphorus additive was added to the tetraester oil to enhance gear surface fatigue life. Test conditions included a gear temperature of 334 K (160 F), a maximum Hertz stress of 1.71 GPa (248 000 psi), and a speed of 10,000 rpm. The gears tested with a 0.1 wt % phosphorus additive showed pitting fatigue life 2.6 times the life of gears tested with the reference tetraester based oil. Although fatigue lives of two groups of gears tested with the sulfur additive in the oil showed improvement over the control group gear life, the results, unlike those obtained with the phosphorus oil, were not considered to be statistically significant.

  6. Critical loads of acidity for surface waters in China.

    PubMed

    Duan, L; Hao, J; Xie, S; Du, K

    2000-01-31

    For further control of acid rain and sulphur dioxide pollution, the Chinese government has designated the Acid Rain Control Zone and the Sulphur Dioxide Pollution Control Zone for those areas that are, or could become, affected by acid deposition or ambient sulphur dioxide concentrations. One of the most important principles for designating the Acid Rain Control Zone is that the critical load is exceeded by the sulphur deposition. Through the steady-state water chemistry method (SSWC), critical loads of acidity for surface waters were mapped based on available data. Results show that surface waters sensitive to acid deposition, i.e. surface waters with low critical loads, are mainly found in north-east China, on the Tibetan Plateau, and in north-west China. Compared with the critical loads of soils, critical loads of surface waters are usually higher in almost all areas in China. The reason for very low critical loads of surface waters in some regions dominated by soils geologically not sensitive to acid deposition may be attributed to the low temperature, high altitude and low runoff. In contrast, surface waters in south China are not susceptible to acid deposition, and so far acidification of surface water has not been found in spite of the heavy acid rain. As can be seen from the critical load exceedance map, nearly 10% of the surface waters are subject to risk of acidification in 1995.

  7. An ontology design pattern for surface water features

    USGS Publications Warehouse

    Sinha, Gaurav; Mark, David; Kolas, Dave; Varanka, Dalia; Romero, Boleslo E.; Feng, Chen-Chieh; Usery, E. Lynn; Liebermann, Joshua; Sorokine, Alexandre

    2014-01-01

    Surface water is a primary concept of human experience but concepts are captured in cultures and languages in many different ways. Still, many commonalities exist due to the physical basis of many of the properties and categories. An abstract ontology of surface water features based only on those physical properties of landscape features has the best potential for serving as a foundational domain ontology for other more context-dependent ontologies. The Surface Water ontology design pattern was developed both for domain knowledge distillation and to serve as a conceptual building-block for more complex or specialized surface water ontologies. A fundamental distinction is made in this ontology between landscape features that act as containers (e.g., stream channels, basins) and the bodies of water (e.g., rivers, lakes) that occupy those containers. Concave (container) landforms semantics are specified in a Dry module and the semantics of contained bodies of water in a Wet module. The pattern is implemented in OWL, but Description Logic axioms and a detailed explanation is provided in this paper. The OWL ontology will be an important contribution to Semantic Web vocabulary for annotating surface water feature datasets. Also provided is a discussion of why there is a need to complement the pattern with other ontologies, especially the previously developed Surface Network pattern. Finally, the practical value of the pattern in semantic querying of surface water datasets is illustrated through an annotated geospatial dataset and sample queries using the classes of the Surface Water pattern.

  8. Rain water transport and storage in a model sandy soil with hydrogel particle additives.

    PubMed

    Wei, Y; Durian, D J

    2014-10-01

    We study rain water infiltration and drainage in a dry model sandy soil with superabsorbent hydrogel particle additives by measuring the mass of retained water for non-ponding rainfall using a self-built 3D laboratory set-up. In the pure model sandy soil, the retained water curve measurements indicate that instead of a stable horizontal wetting front that grows downward uniformly, a narrow fingered flow forms under the top layer of water-saturated soil. This rain water channelization phenomenon not only further reduces the available rain water in the plant root zone, but also affects the efficiency of soil additives, such as superabsorbent hydrogel particles. Our studies show that the shape of the retained water curve for a soil packing with hydrogel particle additives strongly depends on the location and the concentration of the hydrogel particles in the model sandy soil. By carefully choosing the particle size and distribution methods, we may use the swollen hydrogel particles to modify the soil pore structure, to clog or extend the water channels in sandy soils, or to build water reservoirs in the plant root zone.

  9. Water resources data, North Carolina, water year 2001. Volume 1B: Surface-water records

    USGS Publications Warehouse

    Ragland, B.C.; Barker, R.G.; Robinson, J.B.

    2002-01-01

    Water-resources data for the 2001 water year for North Carolina consist of records of stage, discharge, water-quality for streams; stage and contents for lakes and reservoirs; precipitation; and ground water levels and water-quality of ground-water. Volume 1 contains discharge records for 209 gaging stations; stage and contents for 62 lakes and reservoirs; stage for 52 gaging stations; water quality for 101 gaging stations and 91 miscellaneous sites; continuous daily tide stage at 4 sites; and continuous precipitation at 98 sites. Volume 2 contains ground-water-level data from 136 observation wells and ground-water-quality data from 68 wells. Additional water data were collected at 84 sites not involved in the systematic data-collection program, and are published as miscellaneous measurements in Volume 1. The collection of water-resources data in North Carolina is a part of the National Water-Data System operated by the U.S. Geological Survey in cooperation with State, municipal, and Federal agencies.

  10. Structure and properties of water film adsorbed on mica surfaces.

    PubMed

    Zhao, Gutian; Tan, Qiyan; Xiang, Li; Cai, Di; Zeng, Hongbo; Yi, Hong; Ni, Zhonghua; Chen, Yunfei

    2015-09-14

    The structure profiles and physical properties of the adsorbed water film on a mica surface under conditions with different degrees of relative humidity are investigated by a surface force apparatus. The first layer of the adsorbed water film shows ice-like properties, including a lattice constant similar with ice crystal, a high bearing capacity that can support normal pressure as high as 4 MPa, a creep behavior under the action of even a small normal load, and a character of hydrogen bond. Adjacent to the first layer of the adsorbed water film, the water molecules in the outer layer are liquid-like that can flow freely under the action of external loads. Experimental results demonstrate that the adsorbed water layer makes the mica surface change from hydrophilic to weak hydrophobic. The weak hydrophobic surface may induce the latter adsorbed water molecules to form water islands on a mica sheet. PMID:26374054

  11. Structure and properties of water film adsorbed on mica surfaces.

    PubMed

    Zhao, Gutian; Tan, Qiyan; Xiang, Li; Cai, Di; Zeng, Hongbo; Yi, Hong; Ni, Zhonghua; Chen, Yunfei

    2015-09-14

    The structure profiles and physical properties of the adsorbed water film on a mica surface under conditions with different degrees of relative humidity are investigated by a surface force apparatus. The first layer of the adsorbed water film shows ice-like properties, including a lattice constant similar with ice crystal, a high bearing capacity that can support normal pressure as high as 4 MPa, a creep behavior under the action of even a small normal load, and a character of hydrogen bond. Adjacent to the first layer of the adsorbed water film, the water molecules in the outer layer are liquid-like that can flow freely under the action of external loads. Experimental results demonstrate that the adsorbed water layer makes the mica surface change from hydrophilic to weak hydrophobic. The weak hydrophobic surface may induce the latter adsorbed water molecules to form water islands on a mica sheet.

  12. Thermal behavior of water confined in micro porous of clay mineral at additional pressure.

    NASA Astrophysics Data System (ADS)

    Ito, Y.; Takemura, T.; Fujimori, H.; Nagoe, A.; Sugimoto, T.

    2014-12-01

    Water is the most familiar substance. However water has specific properties that has a crystal structure of a dozen and density of that is maximum at 277.15 K. Therefore it understands various natural phenomena to study physical properties of water. Oodo et al study physical properties of water confined in silica gel [1]. They indicate that melting point of water confined in silica gel decrease with decreasing pore size of silica gel. Also in case that pore size is less than 2 nm, water confined in silica gel is unfreezing water at low temperature. It is considered that effect of pore size prevent crystal growth of water. Therefore we are interested in water confined in clay minerals. Clay minerals have a number of water conditions. Also it is thought that water confined in clay minerals show different physical behavior to exist the domain where change with various effect. Therefore we studied a thermal properties and phase behavior of absorption water in clay minerals. In addition, we analyzed the changes in the thermal behavior of absorption water due to the effect of earth pressure that was an environmental factor in the ground. [1] Oodo & Fujimori, J. Non-Cryst. Solids, 357 (2011) 683.

  13. Ground-water/surface-water relations along Honey Creek, Washtenaw County, Michigan, 2003

    USGS Publications Warehouse

    Healy, Denis F.

    2005-01-01

    The U.S. Geological Survey (USGS), in cooperation with the city of Ann Arbor, Mich., investigated the ground-water/ surface-water relations along the lower reaches of Honey Creek, Washtenaw County, Mich., and an unnamed tributary to Honey Creek (the discharge tributary) from June through October 2003. Streamflow in these reaches was artificially high during a naturally low-flow period due to an anthropogenic discharge. Ground-water/surface-water relations were examined by seepage runs (series of streamflow measurements for the computation of streams gains or losses) and measurements of the difference in head between the stream surface and shallow aquifer. Specific conductance and water-temperature measurements were used as ancillary data to help identify gaining and losing reaches. Three seepage runs and four runs in which hydraulic-head differences between the stream and shallow aquifer were measured (piezometer runs) were made during periods of base flow. Streamflow measurements were made at 18 sites for the seepage runs. Instream piezometers were installed at 16 sites and bank piezometers were installed at 2 sites. Two deeper instream piezometers were installed at site 13 on September 4, 2003 to collect additional data on the ground-water/surface-water relations at that site. The seepage runs indicate that the main stem of Honey Creek and the discharge tributary in the study area are overall gaining reaches. The seepage runs also indicate that smaller reaches of Honey Creek and the discharge tributary may be losing reaches and that this relation may change over time with changing hydraulic conditions. The piezometer-run measurements support the seepage-run results on the main stem, whereas piezometer-run measurements both support and conflict with seepage-run measurements on the discharge tributary. Seepage runs give an average for the reach, whereas piezometer head-difference measurements are for a specific area around the piezometer. Data that may appear to be

  14. Surface porosity of stone casts resulting from immersion of addition silicone rubber impressions in disinfectant solutions.

    PubMed

    Hiraguchi, Hisako; Kaketani, Masahiro; Hirose, Hideharu; Kikuchi, Hisaji; Yoneyama, Takayuki

    2014-01-01

    This study investigated the effects of immersion of addition silicone rubber impressions in disinfectant solutions on the surface porosity of the resulting stone casts. Five brands of type 2 and 3 addition silicone rubber impression materials and one brand of type 4 dental stone were used. Impressions of a master die designed to simulate an abutment tooth were immersed in disinfectant for 30 minutes. The disinfectants used were 2% glutaraldehyde solution and 0.55% ortho-phthalaldehyde solution. The surface porosities of stone casts obtained from two brands of impression materials immersed in disinfectant for 30 minutes were determined. Results suggest that impression materials immersed in disinfectant solutions need sufficient time before pouring into dental stone.

  15. Effect of nonionic surfactant addition on Pyrex glass ablation using water-assisted CO2 laser processing

    NASA Astrophysics Data System (ADS)

    Chung, C. K.; Liao, M. W.; Lin, S. L.

    2010-04-01

    Pyrex glass etching using laser ablation is an important technology for the microfluid application to lab-on-a-chip devices but suffers from the formation of surface crack. In this article, the addition of nonionic surfactant to water for glass ablation using water-assisted CO2 laser processing (WACLAP) has been investigated to enhance ablation rate and to eliminate conventional surface defects of cracks in air. WACLAP for Pyrex glass ablation can reduce thermal-stress-induced crack with water cooling and hydrophilic nonionic surfactant to water can enhance ablation performance. Compared to pure water, the 15% weight percent Lauramidopropyl Betaine surfactant solutions for WACLAP can enhance ablation rate from 13.6 to 25 μm/pass of Pyrex glass ablation at a linear laser energy density of 2.11 J/cm, i.e., 24 W power, 114 mm/s scanning speed, and obtain through-wafer etching at 3.16 J/cm for 20 passes without cracks on the surface. Effect of surfactant concentration and linear energy density on WACLAP was also examined. The possible mechanism of surfactant-enhanced phenomenon was discussed by the Newton’s law of viscosity of surfactant solution.

  16. Geochemical Analysis of Surface Water in Rice County, Minnesota

    NASA Astrophysics Data System (ADS)

    Christenson, C.; Prullage, R.; Harvey, M.; Haileab, B.; Harrison, B. K.

    2012-12-01

    Monitoring the quality of surface water is essential to protecting freshwater systems from pollution. For the past four years, Rice County, located in southeastern Minnesota, has been subject to continuous research with the objective of determining the long-term effects of farmland runoff in the water systems. During the summer of 2012, 105 samples were collected from lakes, rivers, and streams. The samples were analyzed for conductivity, nitrate, chloride, calcium, and phosphate. Results show nitrate levels exceeding EPA restrictions (ranging 10-25 ppm) at some locations in the streams along farmlands in the southeast corner of the county. These findings are consistent with past results correlating nitrate levels with farmland runoff, with potential impact on contamination of surficial aquifers as well as significant lake eutrophication observed in the state. ICP-MS results on 67 samples exhibit complex geographical trends across the county not readily attributed to anthropogenic sources. Our findings should inform residents and policy makers taking measures to improve water quality in the county. In addition, annual studies should be continued to monitor water quality in Rice County.

  17. Polyelectrolytes Ability in Reducing Atrazine Concentration in Water: Surface Effects

    PubMed Central

    Heijman, S. G. J.; Lopes, S. I. C.; Rietveld, L. C.

    2014-01-01

    This paper reports on the direct ability of two positively charged organic polyelectrolytes (natural-based and synthetic) to reduce the atrazine concentration in water. The adsorption study was set up using multiple glass vessels with different polymer dosing levels followed by ultrafiltration with a 1 kDa membrane. The addition of polymers exhibited a capability in reducing the atrazine concentration up to a maximum of 60% in surface-to-volume ratio experiments. In the beginning, the theoretical L-type of the isotherm of Giles' classification was expected with an increase in the dosage of the polymer. However, in this study, the conventional type of isotherm was not observed. It was found that the adsorption of the cationic polymer on the negatively charged glass surface was necessary and influential for the removal of atrazine. Surface-to-volume ratio adsorption experiments were performed to elucidate the mechanisms and the polymer configuration. The glass surface area was determined to be a limiting parameter in the adsorption mechanism. PMID:25197693

  18. Polyelectrolytes ability in reducing atrazine concentration in water: surface effects.

    PubMed

    Mohd Amin, Mohamad Faiz; Heijman, S G J; Lopes, S I C; Rietveld, L C

    2014-01-01

    This paper reports on the direct ability of two positively charged organic polyelectrolytes (natural-based and synthetic) to reduce the atrazine concentration in water. The adsorption study was set up using multiple glass vessels with different polymer dosing levels followed by ultrafiltration with a 1 kDa membrane. The addition of polymers exhibited a capability in reducing the atrazine concentration up to a maximum of 60% in surface-to-volume ratio experiments. In the beginning, the theoretical L-type of the isotherm of Giles' classification was expected with an increase in the dosage of the polymer. However, in this study, the conventional type of isotherm was not observed. It was found that the adsorption of the cationic polymer on the negatively charged glass surface was necessary and influential for the removal of atrazine. Surface-to-volume ratio adsorption experiments were performed to elucidate the mechanisms and the polymer configuration. The glass surface area was determined to be a limiting parameter in the adsorption mechanism. PMID:25197693

  19. Effect of Surface Oxidation on Interfacial Water Structure at a Pyrite (100) Surface as Studied by Molecular Dynamics Simulation

    SciTech Connect

    Jin, Jiaqi; Miller, Jan D.; Dang, Liem X.; Wick, Collin D.

    2015-06-01

    In the first part of this paper, a Scanning Electron Microscopy and contact angle study of a pyrite surface (100) is reported describing the relationship between surface oxidation and the hydrophilic surface state. In addition to these experimental results, the following simulated surface states were examined using Molecular Dynamics Simulation (MDS): fresh unoxidized (100) surface; polysulfide at the (100) surface; elemental sulfur at the (100) surface. Crystal structures for the polysulfide and elemental sulfur at the (100) surface were simulated using Density Functional Theory (DFT) quantum chemical calculations. The well known oxidation mechanism which involves formation of a metal deficient layer was also described with DFT. Our MDS results of the behavior of interfacial water at the fresh and oxidized pyrite (100) surfaces without/with the presence of ferric hydroxide include simulated contact angles, number density distribution for water, water dipole orientation, water residence time, and hydrogen-bonding considerations. The significance of the formation of ferric hydroxide islands in accounting for the corresponding hydrophilic surface state is revealed not only from experimental contact angle measurements but also from simulated contact angle measurements using MDS. The hydrophilic surface state developed at oxidized pyrite surfaces has been described by MDS, on which basis the surface state is explained based on interfacial water structure. The Division of Chemical Sciences, Geosciences, and Biosciences, Office of Basic Energy Sciences (BES), of the DOE funded work performed by Liem X. Dang. Battelle operates the Pacific Northwest National Laboratory for DOE. The calculations were carried out using computer resources provided by BES.

  20. A New Antiwear Additive/Surface Pretreatment for PFPE Liquid Lubricants

    NASA Technical Reports Server (NTRS)

    Morales, Wilfredo; Fusaro, Robert L.; Siebert, Mark; Keith, Theo; Jansen, Ralph; Herrera-Fierro, Pilar

    1995-01-01

    Pin-on-disk tribology experiments were conducted on a perfluoroalkylelher (PFPE) liquid lubricant with and without a new PFPE lubricant antiwear additive material, a silane. It was found that the silane provided moderate improvement in the antiwear performance of the PFPE lubricant when applied to the metallic surface as a surface coating or when added to the PFPE as a dispersion (emulsion). Slightly better results were obtained by using the combination of a surface coating and an emulsion of the silane. The silane emulsions or coatings did not affect the friction properties of the lubricant. Micro-Fourier transformation infrared (muFTIR) spectroscopy analysis was performed to study silane transfer films and the degradation of the PFPE. The silane was found to mitigate degradation of the PFPE which may have been the major reason for the improved antiwear performance observed.

  1. Sliding friction and wear behaviors of surface-coated natural serpentine mineral powders as lubricant additive

    NASA Astrophysics Data System (ADS)

    Zhang, Baosen; Xu, Yi; Gao, Fei; Shi, Peijing; Xu, Binshi; Wu, Yixiong

    2011-01-01

    This work aims to investigate the friction and wear properties of surface-coated natural serpentine powders (SP) suspended in diesel engine oil using an Optimal SRV oscillating friction and wear tester. The worn surface was characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS). Results indicated that the additives can improve the wear resistance and decrease friction coefficient of carbon steel friction couples. The 0.5 wt% content of serpentine powders is found most efficient in reducing friction and wear at the load of 50 N. The SEM and XPS analysis results demonstrate that a tribofilm forms on the worn surface, which is responsible for the decrease in friction and wear, mainly with iron oxides, silicon oxides, graphite and organic compounds.

  2. Olefin Metathesis Reaction in Water and in Air Improved by Supramolecular Additives.

    PubMed

    Tomasek, Jasmine; Seßler, Miriam; Gröger, Harald; Schatz, Jürgen

    2015-01-01

    A range of water-immiscible commercially available Grubbs-type precatalysts can be used in ring-closing olefin metathesis reaction in high yields. The synthetic transformation is possible in pure water under ambient conditions. Sulfocalixarenes can help to boost the reactivity of the metathesis reaction by catalyst activation, improved mass transfer, and solubility of reactants in the aqueous reaction media. Additionally, the use of supramolecular additives allows lower catalyst loadings, but still high activity in pure water under aerobic conditions. PMID:26506329

  3. Evaluation of Select Surface Processing Techniques for In Situ Application During the Additive Manufacturing Build Process

    NASA Astrophysics Data System (ADS)

    Book, Todd A.; Sangid, Michael D.

    2016-07-01

    Although additive manufacturing offers numerous performance advantages for different applications, it is not being used for critical applications due to uncertainties in structural integrity as a result of innate process variability and defects. To minimize uncertainty, the current approach relies on the concurrent utilization of process monitoring, post-processing, and non-destructive inspection in addition to an extensive material qualification process. This paper examines an alternative approach by evaluating the application of select surface process techniques, to include sliding severe plastic deformation (SPD) and fine particle shot peening, on direct metal laser sintering-produced AlSi10Mg materials. Each surface processing technique is compared to baseline as-built and post-processed samples as a proof of concept for surface enhancement. Initial results pairing sliding SPD with the manufacture's recommended thermal stress relief cycle demonstrated uniform recrystallization of the microstructure, resulting in a more homogeneous distribution of strain among the microstructure than as-built or post-processed conditions. This result demonstrates the potential for the in situ application of various surface processing techniques during the layerwise direct metal laser sintering build process.

  4. Simulation of water cluster assembly on a graphite surface.

    PubMed

    Lin, C S; Zhang, R Q; Lee, S T; Elstner, M; Frauenheim, Th; Wan, L J

    2005-07-28

    The assembly of small water clusters (H2O)n, n = 1-6, on a graphite surface is studied using a density functional tight-binding method complemented with an empirical van der Waals force correction, with confirmation using second-order Møller-Plesset perturbation theory. It is shown that the optimized geometry of the water hexamer may change its original structure to an isoenergy one when interacting with a graphite surface in some specific orientation, while the smaller water cluster will maintain its cyclic or linear configurations (for the water dimer). The binding energy of water clusters interacting with graphite is dependent on the number of water molecules that form hydrogen bonds, but is independent of the water cluster size. These physically adsorbed water clusters show little change in their IR peak position and leave an almost perfect graphite surface.

  5. Molecular dynamics studies of interfacial water at the alumina surface.

    SciTech Connect

    Argyris, Dr. Dimitrios; Ho, Thomas; Cole, David

    2011-01-01

    Interfacial water properties at the alumina surface were investigated via all-atom equilibrium molecular dynamics simulations at ambient temperature. Al-terminated and OH-terminated alumina surfaces were considered to assess the structural and dynamic behavior of the first few hydration layers in contact with the substrates. Density profiles suggest water layering up to {approx}10 {angstrom} from the solid substrate. Planar density distribution data indicate that water molecules in the first interfacial layer are organized in well-defined patterns dictated by the atomic terminations of the alumina surface. Interfacial water exhibits preferential orientation and delayed dynamics compared to bulk water. Water exhibits bulk-like behavior at distances greater than {approx}10 {angstrom} from the substrate. The formation of an extended hydrogen bond network within the first few hydration layers illustrates the significance of water?water interactions on the structural properties at the interface.

  6. Biogeochemistry of DMS in Surface Waters

    NASA Technical Reports Server (NTRS)

    Dacey, J. W. H.

    1997-01-01

    Dimethylsulfide (DMS) is important in influencing the formation of aerosols in the troposphere over large areas of the world's oceans. Understanding the dynamics of aerosols is important to understanding the earth's radiation balance. In evaluating the factors controlling DMS in the troposphere it is vital to understand the dynamics of DMS in the surface ocean. The biogeochemical processes controlling DMS concentration in seawater are myriad; modeling and theoretical estimation are problematic. At the beginning of this project we believed that we were on the verge of simplifying the ship-track measurement of DMS, and we proposed to deploy such a system to develop a database relating high frequency DMS measurements to biological and physicochemical and optical properties of surface water that can be quantified by remote sensing techniques. We designed a system to measure DMS concomitantly with other basic chemical and biological data in a flow-through system. The project was collaborative between Woods Hole Oceanographic Institution (WHOI) and Bermuda Biological Station for Research (BBSR). The project on which we are reporting was budgeted for only one year with a one year no-cost extension. At WHOI our effort was directed towards designing traps which would be used to concentrate DMS from seawater and allow storage for subsequent analysis. At that time, GC systems were too large for easy long-term deployment on a research vessel like R/V Weatherbird, so we focused on simplifying the shipboard sampling procedure. Initial studies of sample recovery with high levels of DMS suggested that Carboxen 1000, a relatively new carbon molecular sieve, could be used as a stable storage medium. The affinity of Carboxen for DMS is several orders of magnitude higher than gold wool (another adsorbent used for DMS collection) on a weight or volume basis. Furthermore, Carboxen's affinity for DMS is also far less susceptible to humidity than gold wool. Unfortunately, further

  7. Economic Impacts of Surface Mining on Household Drinking Water Supplies

    EPA Science Inventory

    This report provides information on the economic and social impacts of contaminated surface and ground water supplies on residents and households near surface mining operations. The focus is on coal slurry contamination of water supplies in Mingo County, West Virginia, and descr...

  8. 40 CFR 258.27 - Surface water requirements.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Surface water requirements. 258.27 Section 258.27 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES CRITERIA FOR MUNICIPAL SOLID WASTE LANDFILLS Operating Criteria § 258.27 Surface water requirements....

  9. Models of Fate and Transport of Pollutants in Surface Waters

    ERIC Educational Resources Information Center

    Okome, Gloria Eloho

    2013-01-01

    There is the need to answer very crucial questions of "what happens to pollutants in surface waters?" This question must be answered to determine the factors controlling fate and transport of chemicals and their evolutionary state in surface waters. Monitoring and experimental methods are used in establishing the environmental states.…

  10. Calcium carbonate nucleation in an alkaline lake surface water, Pyramid Lake, Nevada, USA

    USGS Publications Warehouse

    Reddy, Michael M.; Hoch, Anthony

    2012-01-01

    Calcium concentration and calcite supersaturation (Ω) needed for calcium carbonate nucleation and crystal growth in Pyramid Lake (PL) surface water were determined during August of 1997, 2000, and 2001. PL surface water has Ω values of 10-16. Notwithstanding high Ω, calcium carbonate growth did not occur on aragonite single crystals suspended PL surface water for several months. However, calcium solution addition to PL surface-water samples caused reproducible calcium carbonate mineral nucleation and crystal growth. Mean PL surface-water calcium concentration at nucleation was 2.33 mM (n = 10), a value about nine times higher than the ambient PL surface-water calcium concentration (0.26 mM); mean Ω at nucleation (109 with a standard deviation of 8) is about eight times the PL surface-water Ω. Calcium concentration and Ω regulated the calcium carbonate formation in PL nucleation experiments and surface water. Unfiltered samples nucleated at lower Ω than filtered samples. Calcium concentration and Ω at nucleation for experiments in the presence of added particles were within one standard deviation of the mean for all samples. Calcium carbonate formation rates followed a simple rate expression of the form, rate (mM/min) = A (Ω) + B. The best fit rate equation "Rate (Δ mM/Δ min) = -0.0026 Ω + 0.0175 (r = 0.904, n = 10)" was statistically significant at greater than the 0.01 confidence level and gives, after rearrangement, Ω at zero rate of 6.7. Nucleation in PL surface water and morphology of calcium carbonate particles formed in PL nucleation experiments and in PL surface-water samples suggest crystal growth inhibition by multiple substances present in PL surface water mediates PL calcium carbonate formation, but there is insufficient information to determine the chemical nature of all inhibitors.

  11. Calcium Carbonate Nucleation in an Alkaline Lake Surface Water, Pyramid Lake, Nevada, USA

    USGS Publications Warehouse

    Reddy, M.M.; Hoch, A.

    2012-01-01

    Calcium concentration and calcite supersaturation (??) needed for calcium carbonate nucleation and crystal growth in Pyramid Lake (PL) surface water were determined during August of 1997, 2000, and 2001. PL surface water has ?? values of 10-16. Notwithstanding high ??, calcium carbonate growth did not occur on aragonite single crystals suspended PL surface water for several months. However, calcium solution addition to PL surface-water samples caused reproducible calcium carbonate mineral nucleation and crystal growth. Mean PL surface-water calcium concentration at nucleation was 2.33 mM (n = 10), a value about nine times higher than the ambient PL surface-water calcium concentration (0.26 mM); mean ?? at nucleation (109 with a standard deviation of 8) is about eight times the PL surface-water ??. Calcium concentration and ?? regulated the calcium carbonate formation in PL nucleation experiments and surface water. Unfiltered samples nucleated at lower ?? than filtered samples. Calcium concentration and ?? at nucleation for experiments in the presence of added particles were within one standard deviation of the mean for all samples. Calcium carbonate formation rates followed a simple rate expression of the form, rate (mM/min) = A (??) + B. The best fit rate equation "Rate (?? mM/?? min) = -0.0026 ?? + 0.0175 (r = 0.904, n = 10)" was statistically significant at greater than the 0.01 confidence level and gives, after rearrangement, ?? at zero rate of 6.7. Nucleation in PL surface water and morphology of calcium carbonate particles formed in PL nucleation experiments and in PL surface-water samples suggest crystal growth inhibition by multiple substances present in PL surface water mediates PL calcium carbonate formation, but there is insufficient information to determine the chemical nature of all inhibitors. ?? 2011 U.S. Government.

  12. Effect of Surface Energy on Freezing Temperature of Water.

    PubMed

    Zhang, Yu; Anim-Danso, Emmanuel; Bekele, Selemon; Dhinojwala, Ali

    2016-07-13

    Previous studies have found that superhydrophobic surfaces are effective in delaying freezing of water droplets. However, the freezing process of water droplets on superhydrophobic surfaces depends on factors such as droplet size, surface area, roughness, and cooling rate. The role of surface energy, independent of any other parameters, in delaying freezing of water is not understood. Here, we have used infrared-visible sum frequency generation spectroscopy (SFG) to study the freezing of water next to solid substrates with water contact angles varying from 5° to 110°. We find that the freezing temperature of water decreases with increasing surface hydrophobicity only when the sample volume is small (∼10 μL). For a larger volume of water (∼300 μL), the freezing temperature is independent of surface energy. For water next to the surfaces with contact angle ≥54°, we observe a strong SFG peak associated with highly coordinated water. This research sheds new light on understanding the key factors in designing new anti-icing coatings. PMID:27314147

  13. Dynamic behavior of interfacila water at the silica surface

    SciTech Connect

    Argyris, Dr. Dimitrios; Cole, David R; Striolo, Alberto

    2009-01-01

    Molecular dynamics simulations were employed to study the dynamics properties of water at the silica-liquid interface at ambient temperature. Three different degrees of hydroxylation of a crystalline silica surface were used. To assess the water dynamic properties we calculated the residence probability and in-plane mean square displacement as a function of distance from the surface. The data indicate that water molecules at the fully hydroxylated surface remain longer, on average, in the interfacial region than in the other cases. By assessing the dynamics of molecular dipole moment and hydrogen-hydrogen vector an anisotropic reorientation was discovered for interfacial water in contact with any of the surfaces considered. However, the features of the anisotropic reorientation observed for water molecules depend strongly on the relative orientation of interfacial water molecules and their interactions with surface hydroxyl groups. On the partially hydroxylated surface, where water molecules with hydrogen-down and hydrogen-up orientation are both found, those water molecules associated with surface hydroxyl groups remain at the adsorbed locations longer and reorient slower than the other water molecules. A number of equilibrium properties, including density profiles, hydrogen bond networks, charge densities, and dipole moment densities are also reported to explain the dynamics results.

  14. Ground water/surface water interaction in a fractured rock aquifer.

    PubMed

    Oxtobee, Jaime P A; Novakowski, Kent S

    2003-01-01

    In a recent field study of ground water/surface water interaction between a bedrock stream and an underlying fractured rock aquifer, it was determined that the majority of ground water discharge occurred through sparsely located vertical fractures. In this paper, the dominant mechanisms governing ground water/surface water exchange in such an environment are investigated using a numerical model. The study was conducted using several conceptual models based on the field study results. Although the field results provided the motivation for the modeling study, it was not intended to match modeling and field results directly. In addition, the extent of capture zones for discharging or recharging fractures was explored. The results of this study are intended to provide a better understanding of contaminant migration in the vicinity of bedrock streams. Based on the numerical results, the rate of ground water discharge (or recharge) was found to depend on the aperture size of the discharging feature, and on the distribution of hydraulic head with depth within the fracture network. It was determined that the extent of both the capture zone and reverse capture zone for an individual fracture can be extremely large, and will be determined by the height of the stream stage, the fracture apertures of the network, and the hydraulic-head distribution within the network. Because both the stream stage and the hydraulic-head distribution are transient, the size of the capture zone and/or the reverse capture zone for an individual fracture may change significantly over time. As a result, the migration path for contaminants within the fracture network and between the surface and subsurface will also vary significantly with time. PMID:13678121

  15. Water-Mediated Interactions between Hydrophilic and Hydrophobic Surfaces.

    PubMed

    Kanduč, Matej; Schlaich, Alexander; Schneck, Emanuel; Netz, Roland R

    2016-09-01

    All surfaces in water experience at short separations hydration repulsion or hydrophobic attraction, depending on the surface polarity. These interactions dominate the more long-ranged electrostatic and van der Waals interactions and are ubiquitous in biological and colloidal systems. Despite their importance in all scenarios where the surface separation is in the nanometer range, the origin of these hydration interactions is still unclear. Using atomistic solvent-explicit molecular dynamics simulations, we analyze the interaction free energies of charge-neutral model surfaces with different elastic and water-binding properties. The surface polarity is shown to be the most important parameter that not only determines the hydration properties and thereby the water contact angle of a single surface but also the surface-surface interaction and whether two surfaces attract or repel. Elastic properties of the surfaces are less important. On the basis of surface contact angles and surface-surface binding affinities, we construct a universal interaction diagram featuring three different interaction regimes-hydration repulsion, cavitation-induced attraction-and for intermediate surface polarities-dry adhesion. On the basis of scaling arguments and perturbation theory, we establish simple combination rules that predict the interaction behavior for combinations of dissimilar surfaces. PMID:27487420

  16. Water-Mediated Interactions between Hydrophilic and Hydrophobic Surfaces.

    PubMed

    Kanduč, Matej; Schlaich, Alexander; Schneck, Emanuel; Netz, Roland R

    2016-09-01

    All surfaces in water experience at short separations hydration repulsion or hydrophobic attraction, depending on the surface polarity. These interactions dominate the more long-ranged electrostatic and van der Waals interactions and are ubiquitous in biological and colloidal systems. Despite their importance in all scenarios where the surface separation is in the nanometer range, the origin of these hydration interactions is still unclear. Using atomistic solvent-explicit molecular dynamics simulations, we analyze the interaction free energies of charge-neutral model surfaces with different elastic and water-binding properties. The surface polarity is shown to be the most important parameter that not only determines the hydration properties and thereby the water contact angle of a single surface but also the surface-surface interaction and whether two surfaces attract or repel. Elastic properties of the surfaces are less important. On the basis of surface contact angles and surface-surface binding affinities, we construct a universal interaction diagram featuring three different interaction regimes-hydration repulsion, cavitation-induced attraction-and for intermediate surface polarities-dry adhesion. On the basis of scaling arguments and perturbation theory, we establish simple combination rules that predict the interaction behavior for combinations of dissimilar surfaces.

  17. Sea-ice and surface water circulation, Alaskan continental shelf

    NASA Technical Reports Server (NTRS)

    Wright, F. F.; Sharma, G. D.; Burns, J. J. (Principal Investigator)

    1973-01-01

    The author has identified the following significant results. Over 1500 water samples from surface and from standard hydrographic depths were collected during June and July 1973 from Bering Sea and Gulf of Alaska. The measurement of temperature, salinity, and productivity indicated that various distinct water masses cover the Bering Sea Shelf. The suspended load in surface waters will be correlated with the ERTS-1 imagery as it becomes available to delineate the surface water circulation. The movement of ice floes in the Bering Strait and Bering Sea indicated that movement of ice varies considerably and may depend on wind stress as well as ocean currents.

  18. Environmental factors influencing isolation of enteroviruses from polluted surface waters.

    PubMed

    Metcalf, T G; Wallis, C; Melnick, J L

    1974-05-01

    The influence of water quality upon the concentration of virus on location was assessed in field studies conducted in the Houston ship channel, Galveston Bay, and Houston waste treatment plants. Clarification of polluted surface waters was accomplished with minimal loss of virus. Virus from clarified sewage effluents and saline waters was then adsorbed and concentrated on textile and membrane filter surfaces. Direct measurements of virus from large volumes of polluted surface waters under existing field conditions were then made using the virus concentrator equipment.

  19. Modeling of water outgassing from metal surfaces (III)

    SciTech Connect

    Minxu Li; H. F. Dylla

    1995-06-01

    A model of water adsorption on metal oxide layers and water outgassing from metal surfaces has been developed. The oxide layer is assumed to have porous structure and a pore length (l) distribution of l/l{sup 2}. Numerical evaluation shows that the quantity of water adsorbed is logarithmic with time within a certain time range as experimentally observed. The outgassing rate from surfaces with adsorbed water distributed uniformly on the inner surfaces of individual pores is shown analytically to be inversely proportional to time. This result is consistent with frequently observed pumpdown curves.

  20. Water Adsorption on the LaMnO3 Surface

    NASA Astrophysics Data System (ADS)

    Billman, Chris; Wang, Yan; Cheng, Hai-Ping

    Studying the adsorption of water on the metallic LaMnO3 surface can provide insight into this complicated surface-adsorbate interaction. Using density functional theory, we investigated the adsorption of a water monomer, dimer, trimer and a monolayer on the surface. The electronic structure of ground state configurations is explored using analysis of density of states, charge density, and crystal orbital overlap populations. We found that the interaction between the surface and water molecules is stronger than hydrogen bonding between molecules, which facilitates wetting of the surface. Adsorbed water molecules form very strong hydrogen bonds, with substantially shifted OH stretch modes. For the monolayer of adsorbed water, a hint of a bilayer is observed with a height separation of only 0.2 Å. However, simulated scanning tunneling microscopy (STM) images and vibrational spectra suggest a significant difference between the two layers due to intermolecular bonding and interaction with the substrate.

  1. Water adsorption on the LaMnO3 surface

    NASA Astrophysics Data System (ADS)

    Billman, Chris R.; Wang, Yan; Cheng, Hai-Ping

    2016-02-01

    Studying the adsorption of water on the metallic LaMnO3 surface can provide insight into this complicated surface-adsorbate interaction. Using density functional theory, we investigated the adsorption of a water monomer, dimer, trimer, and a monolayer on the surface. The electronic structure of ground state configurations is explored using analysis of density of states, charge density, and crystal orbital overlap populations. We found that the interaction between the surface and water molecules is stronger than hydrogen bonding between molecules, which facilitates wetting of the surface. Adsorbed water molecules form very strong hydrogen bonds, with substantially shifted OH stretch modes. For the monolayer of adsorbed water, a hint of a bilayer is observed with a height separation of only 0.2 A˚. However, simulated scanning tunneling microscopy images and vibrational spectra suggest a significant difference between the two layers due to intermolecular bonding and interaction with the substrate.

  2. Herbicide Metabolites in Surface Water and Groundwater: Introduction and Overview

    USGS Publications Warehouse

    Thurman, E.M.; Meyer, M.T.

    1996-01-01

    Several future research topics for herbicide metabolites in surface and ground water are outlined in this chapter. They are herbicide usage, chemical analysis of metabolites, and fate and transport of metabolites in surface and ground water. These three ideas follow the themes in this book, which are the summary of a symposium of the American Chemical Society on herbicide metabolites in surface and ground water. First, geographic information systems allow the spatial distribution of herbicide-use data to be combined with geochemical information on fate and transport of herbicides. Next these two types of information are useful in predicting the kinds of metabolites present and their probable distribution in surface and ground water. Finally, methods development efforts may be focused on these specific target analytes. This chapter discusses these three concepts and provides an introduction to this book on the analysis, chemistry, and fate and transport of herbicide metabolites in surface and ground water.

  3. Surface water quality assessment by environmetric methods.

    PubMed

    Boyacioglu, Hülya; Boyacioglu, Hayal

    2007-08-01

    This environmetric study deals with the interpretation of river water monitoring data from the basin of the Buyuk Menderes River and its tributaries in Turkey. Eleven variables were measured to estimate water quality at 17 sampling sites. Factor analysis was applied to explain the correlations between the observations in terms of underlying factors. Results revealed that, water quality was strongly affected from agricultural uses. Cluster analysis was used to classify stations with similar properties and results distinguished three groups of stations. Water quality at downstream of the river was quite different from the other part. It is recommended to involve the environmetric data treatment as a substantial procedure in assessment of water quality data.

  4. Surface properties and water treatment capacity of surface engineered silica coated with 3-(2-aminoethyl) aminopropyltrimethoxysilane

    NASA Astrophysics Data System (ADS)

    Majewski, Peter; Keegan, Alexandra

    2012-01-01

    This study's focus was on the water-based, one-pot preparation and characterisation of silica particles coated with 3-(2-aminoethyl)aminopropyltrimethoxysilane (Diamo) and the efficiency of the material in removing the pathogens Escherichia coli, Pseudomonas aeruginosa, Mycobacterium immunogenum, Vibrio cholerae, poliovirus, and Cryptosporidium parvum. The water-based processing resulted in Diamo coated silica particles with significantly increased positive surface charge as determined by zeta potential measurements. In addition, X-ray photoelectron spectrometry of pure and Diamo coated silica confirmed the presence of Diamo on the surface of the particles. Thermogravimetric measurements and chemical analysis of the silica indicated a surface concentration of amine groups of about 1 mmol/gsilica. Water treatment tests with the pathogens showed that a dose of about 10 g appeared to be sufficient to remove pathogens from pure water samples which were spiked with pathogen concentrations between about 102 and 104 cfu/mL.

  5. Effect of water depth and water velocity upon the surfacing frequency of the bimodally respiring freshwater turtle, Rheodytes leukops.

    PubMed

    Gordos, Matthew A; Franklin, Craig E; Limpus, Colin J

    2004-08-01

    This study examines the effect of increasing water depth and water velocity upon the surfacing behaviour of the bimodally respiring turtle, Rheodytes leukops. Surfacing frequency was recorded for R. leukops at varying water depths (50, 100, 150 cm) and water velocities (5, 15, 30 cm s(-1)) during independent trials to provide an indirect cost-benefit analysis of aquatic versus pulmonary respiration. With increasing water velocity, R. leukops decreased its surfacing frequency twentyfold, thus suggesting a heightened reliance upon aquatic gas exchange. An elevated reliance upon aquatic respiration, which presumably translates into a decreased air-breathing frequency, may be metabolically more efficient for R. leukops compared to the expenditure (i.e. time and energy) associated with air-breathing within fast-flowing riffle zones. Additionally, R. leukops at higher water velocities preferentially selected low-velocity microhabitats, presumably to avoid the metabolic expenditure associated with high water flow. Alternatively, increasing water depth had no effect upon the surfacing frequency of R. leukops, suggesting little to no change in the respiratory partitioning of the species across treatment settings. Routinely long dives (>90 min) recorded for R. leukops indicate a high reliance upon aquatic O2 uptake regardless of water depth. Moreover, metabolic and temporal costs attributed to pulmonary gas exchange within a pool-like environment were likely minimal for R. leukops, irrespective of water depth. PMID:15277564

  6. Electron at the Surface of Water: Dehydrated or Not?

    PubMed

    Uhlig, Frank; Marsalek, Ondrej; Jungwirth, Pavel

    2013-01-17

    The hydrated electron is a crucial species in radiative processes, and it has been speculated that its behavior at the water surface could lead to specific interfacial chemical properties. Here, we address fundamental questions concerning the structure and energetics of an electron at the surface of water. We use the method of ab initio molecular dynamics, which was shown to provide a faithful description of solvated electrons in large water clusters and in bulk water. The present results clearly demonstrate that the surface electron is mostly buried in the interfacial water layer, with only about 10 % of its density protruding into the vapor phase. Consequently, it has a structure that is very similar to that of an electron solvated in the aqueous bulk. This points to a general feature of charges at the surface of water, namely, that they do not behave as half-dehydrated but rather as almost fully hydrated species.

  7. Water adsorbate influence on the Cu(110) surface optical response

    NASA Astrophysics Data System (ADS)

    Baghbanpourasl, Amirreza; Schmidt, Wolf Gero; Denk, Mariella; Cobet, Christoph; Hohage, Michael; Zeppenfeld, Peter; Hingerl, Kurt

    2015-11-01

    Surface reflectance anisotropy may be utilized for characterizing surfaces, interfaces, and adsorption structures. Here, the reflectance anisotropy and surface dielectric functions of the thermodynamically most favored water adsorbate structures on the Cu(110) surface (i.e. hexagonal bilayers, pentagonal chains, and partially dissociated water structures) are calculated from density-functional theory and compared with recent experimental data. It is shown that the water overlayer structures modify in a geometry-specific way the optical anisotropy of the bare surface which can be exploited for in situ determination of the adsorption structures. For hexagonal bilayer overlayer geometries, strong features in the vacuum ultraviolet region are predicted. The theoretical analysis shows a noticeable influence of intraband transitions also for higher photon energies and rather slight influences of the van der Waals interaction on the spectral signatures. Water induced strain effects on the surface optical response are found to be negligible.

  8. Water resources data, Idaho, 2003; Volume 1. Surface water records for Great Basin and Snake River basin above King Hill

    USGS Publications Warehouse

    Brennan, T.S.; Lehmann, A.K.; O'Dell, I.

    2004-01-01

    Water resources data for the 2003 water year for Idaho consists of records of stage, discharge, and water quality of streams; stage, contents, and water quality of lakes and reservoirs; discharge of irrigation diversions; and water levels and water quality of groundwater. The three volumes of this report contain discharge records for 208 stream-gaging stations and 14 irrigation diversions; stage only records for 6 stream-gaging stations; stage only for 6 lakes and reservoirs; contents only for 13 lakes and reservoirs; water-quality for 50 stream-gaging stations and partial record sites, 3 lakes sites, and 398 groundwater wells; and water levels for 427 observation network wells and 900 special project wells. Additional water data were collected at various sites not involved in the systematic data collection program and are published as miscellaneous measurements. Volumes 1 & 2 contain the surface-water and surface-water-quality records. Volume 3 contains the ground-water and ground-water-quality records. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State and Federal agencies in Idaho, adjacent States, and Canada.

  9. Water resources data, Idaho, 2004; Volume 1. Surface water records for Great Basin and Snake River basin above King Hill

    USGS Publications Warehouse

    Brennan, T.S.; Lehmann, A.K.; O'Dell, I.

    2005-01-01

    Water resources data for the 2004 water year for Idaho consists of records of stage, discharge, and water quality of streams; stage, contents, and water quality of lakes and reservoirs; discharge of irrigation diversions; and water levels and water quality of groundwater. The three volumes of this report contain discharge records for 209 stream-gaging stations and 8 irrigation diversions; stage only records for 6 stream-gaging stations; stage only for 6 lakes and reservoirs; contents only for 13 lakes and reservoirs; water-quality for 39 stream-gaging stations and partial record sites, 3 lakes sites, and 395 groundwater wells; and water levels for 425 observation network wells and 900 special project wells. Additional water data were collected at various sites not involved in the systematic data collection program and are published as miscellaneous measurements. Volumes 1 & 2 contain the surface-water and surface-water-quality records. Volume 3 contains the ground-water and ground-water-quality records. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State and Federal agencies in Idaho, adjacent States, and Canada.

  10. Calcite surface structure and reactivity: molecular dynamics simulations and macroscopic surface modelling of the calcite-water interface.

    PubMed

    Wolthers, M; Di Tommaso, D; Du, Z; de Leeuw, N H

    2012-11-21

    Calcite-water interactions are important not only in carbon sequestration and the global carbon cycle, but also in contaminant behaviour in calcite-bearing host rock and in many industrial applications. Here we quantify the effect of variations in surface structure on calcite surface reactivity. Firstly, we employ classical Molecular Dynamics simulations of calcite surfaces containing an etch pit and a growth terrace, to show that the local environment in water around structurally different surface sites is distinct. In addition to observing the expected formation of more calcium-water interactions and hydrogen-bonds at lower-coordinated sites, we also observed subtle differences in hydrogen bonding around acute versus obtuse edges and corners. We subsequently used this information to refine the protonation constants for the calcite surface sites, according to the Charge Distribution MUltiSite Ion Complexation (CD-MUSIC) approach. The subtle differences in hydrogen bonding translate into markedly different charging behaviour versus pH, in particular for acute versus obtuse corner sites. The results show quantitatively that calcite surface reactivity is directly related to surface topography. The information obtained in this study is not only crucial for the improvement of existing macroscopic surface models of the reactivity of calcite towards contaminants, but also improves our atomic-level understanding of mineral-water interactions.

  11. Water surface tension modulates the swarming mechanics of Bacillus subtilis.

    PubMed

    Ke, Wan-Ju; Hsueh, Yi-Huang; Cheng, Yu-Chieh; Wu, Chih-Ching; Liu, Shih-Tung

    2015-01-01

    Many Bacillus subtilis strains swarm, often forming colonies with tendrils on agar medium. It is known that B. subtilis swarming requires flagella and a biosurfactant, surfactin. In this study, we find that water surface tension plays a role in swarming dynamics. B. subtilis colonies were found to contain water, and when a low amount of surfactin is produced, the water surface tension of the colony restricts expansion, causing bacterial density to rise. The increased density induces a quorum sensing response that leads to heightened production of surfactin, which then weakens water surface tension to allow colony expansion. When the barrier formed by water surface tension is breached at a specific location, a stream of bacteria swarms out of the colony to form a tendril. If a B. subtilis strain produces surfactin at levels that can substantially weaken the overall water surface tension of the colony, water floods the agar surface in a thin layer, within which bacteria swarm and migrate rapidly. This study sheds light on the role of water surface tension in regulating B. subtilis swarming, and provides insight into the mechanisms underlying swarming initiation and tendril formation.

  12. Crocodylus niloticus (Crocodilia) is highly sensitive to water surface waves.

    PubMed

    Grap, Nadja J; Monzel, Anna S; Kohl, Tobias; Bleckmann, Horst

    2015-10-01

    Crocodiles show oriented responses to water surface wave stimuli but up to now behavioral thresholds are missing. This study determines the behavioral thresholds of crocodilians to water surface waves. Nile crocodiles (Crocodylus niloticus) were conditioned to respond to single-frequency water surface wave stimuli (duration 1150 ms, frequency 15, 30, 40, 60 and 80 Hz), produced by blowing air onto the water surface. Our study shows that C. niloticus is highly sensitive to capillary water surface waves. Threshold values decreased with increasing frequency and ranged between 10.3 μm (15 Hz) and 0.5 μm (80 Hz) peak-to-peak wave amplitude. For the frequencies 15 Hz and 30 Hz the sensitivity of one spectacled caiman (Caiman crocodilus) to water surface waves was also tested. Threshold values were 12.8 μm (15 Hz) down to 1.76 μm (30 Hz), i.e. close to the threshold values of C. niloticus. The surface wave sensitivity of crocodiles is similar to the surface wave sensitivity of semi-aquatic insects and fishing spiders but does not match the sensitivity of surface-feeding fishes which is higher by one to two orders of magnitude.

  13. Crocodylus niloticus (Crocodilia) is highly sensitive to water surface waves.

    PubMed

    Grap, Nadja J; Monzel, Anna S; Kohl, Tobias; Bleckmann, Horst

    2015-10-01

    Crocodiles show oriented responses to water surface wave stimuli but up to now behavioral thresholds are missing. This study determines the behavioral thresholds of crocodilians to water surface waves. Nile crocodiles (Crocodylus niloticus) were conditioned to respond to single-frequency water surface wave stimuli (duration 1150 ms, frequency 15, 30, 40, 60 and 80 Hz), produced by blowing air onto the water surface. Our study shows that C. niloticus is highly sensitive to capillary water surface waves. Threshold values decreased with increasing frequency and ranged between 10.3 μm (15 Hz) and 0.5 μm (80 Hz) peak-to-peak wave amplitude. For the frequencies 15 Hz and 30 Hz the sensitivity of one spectacled caiman (Caiman crocodilus) to water surface waves was also tested. Threshold values were 12.8 μm (15 Hz) down to 1.76 μm (30 Hz), i.e. close to the threshold values of C. niloticus. The surface wave sensitivity of crocodiles is similar to the surface wave sensitivity of semi-aquatic insects and fishing spiders but does not match the sensitivity of surface-feeding fishes which is higher by one to two orders of magnitude. PMID:26153334

  14. Water Quality Indicators Guide [and Teacher's Handbook]: Surface Waters.

    ERIC Educational Resources Information Center

    Terrell, Charles R.; Perfetti, Patricia Bytnar

    This guide aids in finding water quality solutions to problems from sediment, animal wastes, nutrients, pesticides, and salts. The guide allows users to learn the fundamental concepts of water quality assessment by extracting basic tenets from geology, hydrology, biology, ecology, and wastewater treatment. An introduction and eight chapters are…

  15. Surface-Water Quality-Assurance Plan for the USGS Wisconsin Water Science Center

    USGS Publications Warehouse

    Garn, H.S.

    2007-01-01

    This surface-water quality-assurance plan documents the standards, policies, and procedures used by the Wisconsin Water Science Center of the U.S. Geological Survey, Water Resources Discipline, for activities related to the collection, processing, storage, analysis, management, and publication of surface-water data. The roles and responsibilities of Water Science Center personnel in following these policies and procedures including those related to safety and training are presented.

  16. OCCURRENCE OF ENTERIC VIRUSES IN SURFACE WATERS

    EPA Science Inventory

    Human enteric viruses cause a number of diseases when individuals are exposed to contaminated drinking & recreational waters. Vaccination against poliovirus has virtually eliminated poliomyelitis from the planet. Other members of enterovirus group cause numerous diseases. Hepatit...

  17. Interaction of surface and subsurface waters in the system

    NASA Astrophysics Data System (ADS)

    Mazukhina, Svetlana; Masloboev, Vladimir; Chudnenko, Konstantin; Bychinski, Valerii; Sandimirov, Sergey

    2010-05-01

    Purpose of the study - to assess the influence of the Khibiny massif on the formation of the chemical composition of surface and subsurface waters, generated within its boundaries using physical-chemical modeling ("Selector" software package). Objects of monitoring - rivers with sources in the upper reaches of the Khibiny massif (surface waters), and boreholes, located in these rivers' valleys (subsurface waters) have been chosen as objects of monitoring. Processes of formation of surface and subsurface waters, generated within the boundaries of the Khibiny massif, have been considered within the framework of a unified system "water-rock-atmosphere-carbon". The initial data of the model: chemical compositions of the Khibiny massif rocks and chemical analyses of atmospheric and surface waters. Besides, there have been considered Clarke concentrations S, Cl, F, C, their influence on the formation of chemical composition of water solutions; geochemical mobility of chemical elements. The previously developed model has been improved with the purpose of assessment of the influence of organic substance, either liquid or solid, on the formation of the chemical composition of water. The record of the base model of the multisystem includes 24 independent components (Al-B-Br-Ar-He-Ne-C-Ca-Cl-F-K-Mg-Mn-N-Na-P-S-Si-Sr-Cu-Zn-H-O-e), 872 dependent components, including, in a water solution - 295, in a gas phase - 76, liquid hydrocarbons - 111, solid phases, organic and mineral substances - 390. The record of solid phases of multisystem is made with consideration of the mineral composition of the Khibiny massif. Using the created model, the physical-chemical modeling of surface and subsurface water generation has been carried out: 1. The system "water-rock-atmosphere" has been studied, depending on the interaction degree (ksi) of rock with water. A model like this allowed investigating the interactions of surface waters (rivers and lakes) with rocks that form the Khibiny massif. 2

  18. Density functional theory study of the effects of alloying additions on sulfur adsorption on nickel surfaces

    NASA Astrophysics Data System (ADS)

    Malyi, Oleksandr I.; Chen, Zhong; Kulish, Vadym V.; Bai, Kewu; Wu, Ping

    2013-01-01

    Reactions of hydrogen sulfide (H2S) with Nickel/Ytrria-doped zirconia (Ni/YDZ) anode materials might cause degradation of the performance of solid oxide fuel cells when S containing fuels are used. In this paper, we employ density functional theory to investigate S adsorption on metal (M)-doped and undoped Ni(0 0 1) and Ni(1 1 1) surfaces. Based on the performed calculations, we analyze the effects of 12 alloying additions (Ag, Au, Al, Bi, Cd, Co, Cu, Fe, Sn, Sb, V, and Zn) on the temperature of transition between clean (S atoms do not adsorb on the surfaces) and contaminated (S atoms can adsorb on the surfaces spontaneously) M-doped Ni surfaces for different concentrations of H2S in the fuel. Predicted results are consistent with many experimental studies relevant to S poisoning of both Ni/YDZ and M-doped Ni/YDZ anode materials. This study is important to understand S poisoning phenomena and to develop new S tolerant anode materials.

  19. Asymmetric Anion-π Catalysis: Enamine Addition to Nitroolefins on π-Acidic Surfaces.

    PubMed

    Zhao, Yingjie; Cotelle, Yoann; Avestro, Alyssa-Jennifer; Sakai, Naomi; Matile, Stefan

    2015-09-16

    Here we provide experimental evidence for anion-π catalysis of enamine chemistry and for asymmetric anion-π catalysis. A proline for enamine formation on one side and a glutamic acid for nitronate protonation on the other side are placed to make the enamine addition to nitroolefins occur on the aromatic surface of π-acidic naphthalenediimides. With increasing π acidity of the formally trifunctional catalysts, rate and enantioselectivity of the reaction increase. Mismatched and more flexible controls reveal that the importance of rigidified, precisely sculpted architectures increases with increasing π acidity as well. The absolute configuration of stereogenic sulfoxide acceptors at the edge of the π-acidic surface has a profound influence on asymmetric anion-π catalysis and, if perfectly matched, affords the highest enantio- and diastereoselectivity.

  20. A Novel Approach for Direct Measurement of Cumulative Water and Solute Mass Fluxes using a Passive Surface Water Flux Meter

    NASA Astrophysics Data System (ADS)

    Padowski, J. C.; Jawitz, J. W.; Hatfield, K.; Annable, M. D.; Cho, J.; Klammler, H.

    2005-12-01

    This work describes the development of a novel technique for passive measurement of pollutant loads in flowing surface water systems. Recent changes to the Clean Water Act have prompted a major initiative for the development of a national list of impaired surface waters. According to the law, every state is now responsible for defining the use of each water body and creating a Total Maximum Daily Load (TMDL) to regulate all pollutant loads entering these systems. Current methods for determining pollutant loads typically involve collecting separate instantaneous measurements of water velocities and solute concentrations at discrete points in space and time. The data must be combined, interpolated and integrated after collection to arrive at estimates of local cumulative solute flux and discharge. The frequency with which these parameters are measured typically rely upon the availability of resources (time, money, manpower, etc.) and are often undersampled. A method is presented here for direct measurement of cumulative surface water flux (discharge) and solute flux using a Passive Surface Water Flux Meter (PSFM). The PSFM is designed to directly measure local cumulative water and solute mass fluxes in surface water flow without any active components transmitting or logging data over time. This passive integration of water and solute mass fluxes eliminates the need for independent water flux and concentration measurements and any additional computations. Laboratory trials under steady state and transient conditions were used to test the appropriateness of the PSFM as a device for collecting water quality data. Results from steady state experiments verified the ability of PSFM to accurately measure cumulative water and solute mass flux. Preliminary results from investigations under transient flow conditions also showed promise for measuring pollutant loads in natural systems with this device.

  1. Effects of water and nitrogen addition on species turnover in temperate grasslands in northern China.

    PubMed

    Xu, Zhuwen; Wan, Shiqiang; Ren, Haiyan; Han, Xingguo; Li, Mai-He; Cheng, Weixin; Jiang, Yong

    2012-01-01

    Global nitrogen (N) deposition and climate change have been identified as two of the most important causes of current plant diversity loss. However, temporal patterns of species turnover underlying diversity changes in response to changing precipitation regimes and atmospheric N deposition have received inadequate attention. We carried out a manipulation experiment in a steppe and an old-field in North China from 2005 to 2009, to test the hypothesis that water addition enhances plant species richness through increase in the rate of species gain and decrease in the rate of species loss, while N addition has opposite effects on species changes. Our results showed that water addition increased the rate of species gain in both the steppe and the old field but decreased the rates of species loss and turnover in the old field. In contrast, N addition increased the rates of species loss and turnover in the steppe but decreased the rate of species gain in the old field. The rate of species change was greater in the old field than in the steppe. Water interacted with N to affect species richness and species turnover, indicating that the impacts of N on semi-arid grasslands were largely mediated by water availability. The temporal stability of communities was negatively correlated with rates of species loss and turnover, suggesting that water addition might enhance, but N addition would reduce the compositional stability of grasslands. Experimental results support our initial hypothesis and demonstrate that water and N availabilities differed in the effects on rate of species change in the temperate grasslands, and these effects also depend on grassland types and/or land-use history. Species gain and loss together contribute to the dynamic change of species richness in semi-arid grasslands under future climate change.

  2. Effects of Water and Nitrogen Addition on Species Turnover in Temperate Grasslands in Northern China

    PubMed Central

    Xu, Zhuwen; Wan, Shiqiang; Ren, Haiyan; Han, Xingguo; Li, Mai-He; Cheng, Weixin; Jiang, Yong

    2012-01-01

    Global nitrogen (N) deposition and climate change have been identified as two of the most important causes of current plant diversity loss. However, temporal patterns of species turnover underlying diversity changes in response to changing precipitation regimes and atmospheric N deposition have received inadequate attention. We carried out a manipulation experiment in a steppe and an old-field in North China from 2005 to 2009, to test the hypothesis that water addition enhances plant species richness through increase in the rate of species gain and decrease in the rate of species loss, while N addition has opposite effects on species changes. Our results showed that water addition increased the rate of species gain in both the steppe and the old field but decreased the rates of species loss and turnover in the old field. In contrast, N addition increased the rates of species loss and turnover in the steppe but decreased the rate of species gain in the old field. The rate of species change was greater in the old field than in the steppe. Water interacted with N to affect species richness and species turnover, indicating that the impacts of N on semi-arid grasslands were largely mediated by water availability. The temporal stability of communities was negatively correlated with rates of species loss and turnover, suggesting that water addition might enhance, but N addition would reduce the compositional stability of grasslands. Experimental results support our initial hypothesis and demonstrate that water and N availabilities differed in the effects on rate of species change in the temperate grasslands, and these effects also depend on grassland types and/or land-use history. Species gain and loss together contribute to the dynamic change of species richness in semi-arid grasslands under future climate change. PMID:22768119

  3. National water summary 1985: Hydrologic events and surface-water resources

    USGS Publications Warehouse

    Moody, David W.; Chase, Edith B.; Aronson, David A.

    1986-01-01

    The surface-water resources of the United States, the focal point for this National Water Summary, are extensively developed and managed to provide water supplies, hydroelectric power, navigation, recreational opportunities, and sufficient instream flows to maintain fish and wildlife habitats and adequate water quality. Surface water represents 77 percent of the Nation's total freshwater withdrawals, 65 percent of public supplies, 74 percent of self- supplied industries, excluding thermoelectric power generation, and 60 percent of irrigation. In only 10 States does surface water provide less than half of the total withdrawals.

  4. Behavior of severely supercooled water drops impacting on superhydrophobic surfaces

    NASA Astrophysics Data System (ADS)

    Maitra, Tanmoy; Antonini, Carlo; Tiwari, Manish K.; Mularczyk, Adrian; Imeri, Zulkufli; Schoch, Philippe; Poulikakos, Dimos

    2014-11-01

    Surface icing, commonplace in nature and technology, has broad implications to daily life. To prevent surface icing, superhydrophobic surfaces/coatings with rationally controlled roughness features (both at micro and nano-scale) are considered to be a promising candidate. However, to fabricate/synthesize a high performance icephobic surface or coating, understanding the dynamic interaction between water and the surface during water drop impact in supercooled state is necessary. In this work, we investigate the water/substrate interaction using drop impact experiments down to -17°C. It is found that the resulting increased viscous effect of water at low temperature significantly affects all stages of drop dynamics such as maximum spreading, contact time and meniscus penetration into the superhydrophobic texture. Most interestingly, the viscous effect on the meniscus penetration into roughness feature leads to clear change in the velocity threshold for rebounding to sticking transition by 25% of supercooled drops. Swiss National Science Foundation (SNF) Grant 200021_135479.

  5. Interaction between water cluster ions and mica surface

    SciTech Connect

    Ryuto, Hiromichi Ohmura, Yuki; Nakagawa, Minoru; Takeuchi, Mitsuaki; Takaoka, Gikan H.

    2014-03-15

    Water cluster ion beams were irradiated on mica surfaces to investigate the interaction between molecular cluster ions and a mica surface. The contact angle of the mica surface increased with increasing dose of the water cluster ion beam, but the increase in the contact angle was smaller than that induced by an ethanol cluster ion beam. The surface roughness also increased with increasing dose of the water cluster ion beam, whereas the intensity of K 2p x-ray photoelectron spectroscopy peaks decreased with increasing dose of the water cluster ion beam. The decrease in the number of potassium atoms together with the increase in the surface roughness may be the causes of the increase in the contact angle.

  6. Molecular dynamics simulations of water droplets on polymer surfaces.

    PubMed

    Hirvi, Janne T; Pakkanen, Tapani A

    2006-10-14

    Molecular dynamics simulations were used to study the wetting of polymer surfaces with water. Contact angles of water droplets on crystalline and two amorphous polyethylene (PE) and poly(vinyl chloride) (PVC) surfaces were extracted from atomistic simulations. Crystalline surfaces were produced by duplicating the unit cell of an experimental crystal structure, and amorphous surfaces by pressing the bulk polymer step by step at elevated temperature between two repulsive grid surfaces to a target density. Different-sized water droplets on the crystalline PE surface revealed a slightly positive line tension on the order of 10(-12)-10(-11) N, whereas droplets on crystalline PVC did not yield a definite line tension. Microscopic contact angles produced by the simple point charge (SPC) water model were mostly a few degrees smaller than those produced by the extended SPC model, which, as the model with lowest bulk energy, presents an upper boundary for contact angles. The macroscopic contact angle for the SPC model was 94 degrees on crystalline PVC and 113 degrees on crystalline PE. Amorphicity of the surface increased the water contact angle on PE but decreased it on PVC, for both water models. If the simulated contact angles on crystalline and amorphous surfaces are combined in proportion to the crystallinity of the polymer in question, simulated values in relatively good agreement with measured values are obtained.

  7. [Mapping sensitivity of surface waters to acidification in China].

    PubMed

    Ye, Xuemei; Hao, Jiming; Duan, Lei; Zhou, Zhongping

    2002-01-30

    Acidification of surface waters can be decided by some environmental factors, such as soil's buffering capacity, neutralization capacity of bedrock to acid deposition and types of land use, among which the most important factor is the soil's resistance to acidification. Therefore, information about soils, geology and land use can be used to predict the regional occurrence of acidification surface waters under different flows. In this paper, information and data about Chinese soils, geology and land use types were collected to determine and to map the sensitivity of surface waters to acidification. Results showed that in China, most surface waters were not sensitive to acidification. The few most sensitive surface waters were located in the north part of Northeastern China, accounting for 2.67% of all the country land. It was the combined results of strongly acidified ortho podzolic soil, acidified bedrock and coniferous forest. Surface waters which were not very sensitive to acidification were distributed both in the region of dark brown forest soil in Northeastern China and in the ferralsol and yellow-brown earth area in Southern China, occupying 15.2% of all the country land. The other surface waters which distributed on 82.11% of all the country land were not sensitive to acidification at all. Most in the Northern China because of the high resistance of soils to acidification and the others were in the Southern China where calcareous soils and agricultural lands were widely distributed. Since soils were quite resistant to acid, acidification of surface waters of large area will not likely occur in the southern region of China suffering from heavy acid deposition in the near future. Nevertheless, the acid deposition in Northern China should be controlled as soon as possible in case that acidified surface waters will be found there.

  8. Effects of Water and Nitrogen Addition on Ecosystem Carbon Exchange in a Meadow Steppe

    PubMed Central

    Wang, Yunbo; Jiang, Qi; Yang, Zhiming; Sun, Wei; Wang, Deli

    2015-01-01

    A changing precipitation regime and increasing nitrogen deposition are likely to have profound impacts on arid and semiarid ecosystem C cycling, which is often constrained by the timing and availability of water and nitrogen. However, little is known about the effects of altered precipitation and nitrogen addition on grassland ecosystem C exchange. We conducted a 3-year field experiment to assess the responses of vegetation composition, ecosystem productivity, and ecosystem C exchange to manipulative water and nitrogen addition in a meadow steppe. Nitrogen addition significantly stimulated aboveground biomass and net ecosystem CO2 exchange (NEE), which suggests that nitrogen availability is a primary limiting factor for ecosystem C cycling in the meadow steppe. Water addition had no significant impacts on either ecosystem C exchange or plant biomass, but ecosystem C fluxes showed a strong correlation with early growing season precipitation, rather than whole growing season precipitation, across the 3 experimental years. After we incorporated water addition into the calculation of precipitation regimes, we found that monthly average ecosystem C fluxes correlated more strongly with precipitation frequency than with precipitation amount. These results highlight the importance of precipitation distribution in regulating ecosystem C cycling. Overall, ecosystem C fluxes in the studied ecosystem are highly sensitive to nitrogen deposition, but less sensitive to increased precipitation. PMID:26010888

  9. Numerical study of surface water waves generated by mass movement

    NASA Astrophysics Data System (ADS)

    Ghozlani, Belgacem; Hafsia, Zouhaier; Maalel, Khlifa

    2013-10-01

    In this paper waves generated by two-dimensional mass movement are simulated using a numerical model based on the full hydrodynamic coupling between rigid-body motion and ambient fluid flow. This approach has the capability to represent the dynamics of the moving rigid body, which avoids the need to prescribe the body velocity based on the data measurements. This model is implemented in the CFX code and uses the Reynolds average Navier-Stokes equations solver coupled to the recently developed immersed solid technique. The latter technique allows us to follow implicitly the motion of the solid block based on the rigid body solver. The volume-of-fluid method is used to track the free surface locations. The accuracy of the present model is firstly examined against the simple physical case of a freely falling rigid body into water reproducing Scott Russell's solitary waves. More complex and realistic simulations of aerial and submarine mass-movement, simulated by a rigid wedge sliding into water along a 45° slope, are then performed. Simulated results of the aerial mass movement show the complex flow patterns in terms of the velocity fields and free surface profiles. Results are in good agreement with the available experimental data. In addition, the physical processes associated with the generation of water wave by two-dimensional submarine mass-movement are explored. The effects of the initial submergence and specific gravity on the slide mass kinematics and maximum wave amplitude are investigated. The terminal velocity and initial acceleration of the slide mass are well predicted when compared to experimental results. It is found that the initial submergence did not have a significant effect on the initial acceleration of the slide block centre of mass. However, it depends nonlinearly\\vadjust{\

  10. Interaction of water with bioactive glass surfaces

    NASA Astrophysics Data System (ADS)

    Zeitler, Todd R.; Cormack, A. N.

    2006-08-01

    The bioactivity of bioactive glasses is related to their dissolution in the presence of body fluid, or water. The dissolution process involves disruption of the tetrahedral network structure through the formation of silanol groups on the take-up of water by bioactive glasses. Molecular dynamics simulations show that the dissolution energy varies considerably depending on the nature and environment of the Si-O-Si bond being broken. However, no obvious correlation with bioactivity is observed, suggesting that although the network disruption is a necessary process, it is not rate determining.

  11. Multivariate qualitative analysis of banned additives in food safety using surface enhanced Raman scattering spectroscopy

    NASA Astrophysics Data System (ADS)

    He, Shixuan; Xie, Wanyi; Zhang, Wei; Zhang, Liqun; Wang, Yunxia; Liu, Xiaoling; Liu, Yulong; Du, Chunlei

    2015-02-01

    A novel strategy which combines iteratively cubic spline fitting baseline correction method with discriminant partial least squares qualitative analysis is employed to analyze the surface enhanced Raman scattering (SERS) spectroscopy of banned food additives, such as Sudan I dye and Rhodamine B in food, Malachite green residues in aquaculture fish. Multivariate qualitative analysis methods, using the combination of spectra preprocessing iteratively cubic spline fitting (ICSF) baseline correction with principal component analysis (PCA) and discriminant partial least squares (DPLS) classification respectively, are applied to investigate the effectiveness of SERS spectroscopy for predicting the class assignments of unknown banned food additives. PCA cannot be used to predict the class assignments of unknown samples. However, the DPLS classification can discriminate the class assignment of unknown banned additives using the information of differences in relative intensities. The results demonstrate that SERS spectroscopy combined with ICSF baseline correction method and exploratory analysis methodology DPLS classification can be potentially used for distinguishing the banned food additives in field of food safety.

  12. Multivariate qualitative analysis of banned additives in food safety using surface enhanced Raman scattering spectroscopy.

    PubMed

    He, Shixuan; Xie, Wanyi; Zhang, Wei; Zhang, Liqun; Wang, Yunxia; Liu, Xiaoling; Liu, Yulong; Du, Chunlei

    2015-02-25

    A novel strategy which combines iteratively cubic spline fitting baseline correction method with discriminant partial least squares qualitative analysis is employed to analyze the surface enhanced Raman scattering (SERS) spectroscopy of banned food additives, such as Sudan I dye and Rhodamine B in food, Malachite green residues in aquaculture fish. Multivariate qualitative analysis methods, using the combination of spectra preprocessing iteratively cubic spline fitting (ICSF) baseline correction with principal component analysis (PCA) and discriminant partial least squares (DPLS) classification respectively, are applied to investigate the effectiveness of SERS spectroscopy for predicting the class assignments of unknown banned food additives. PCA cannot be used to predict the class assignments of unknown samples. However, the DPLS classification can discriminate the class assignment of unknown banned additives using the information of differences in relative intensities. The results demonstrate that SERS spectroscopy combined with ICSF baseline correction method and exploratory analysis methodology DPLS classification can be potentially used for distinguishing the banned food additives in field of food safety.

  13. Multivariate qualitative analysis of banned additives in food safety using surface enhanced Raman scattering spectroscopy.

    PubMed

    He, Shixuan; Xie, Wanyi; Zhang, Wei; Zhang, Liqun; Wang, Yunxia; Liu, Xiaoling; Liu, Yulong; Du, Chunlei

    2015-02-25

    A novel strategy which combines iteratively cubic spline fitting baseline correction method with discriminant partial least squares qualitative analysis is employed to analyze the surface enhanced Raman scattering (SERS) spectroscopy of banned food additives, such as Sudan I dye and Rhodamine B in food, Malachite green residues in aquaculture fish. Multivariate qualitative analysis methods, using the combination of spectra preprocessing iteratively cubic spline fitting (ICSF) baseline correction with principal component analysis (PCA) and discriminant partial least squares (DPLS) classification respectively, are applied to investigate the effectiveness of SERS spectroscopy for predicting the class assignments of unknown banned food additives. PCA cannot be used to predict the class assignments of unknown samples. However, the DPLS classification can discriminate the class assignment of unknown banned additives using the information of differences in relative intensities. The results demonstrate that SERS spectroscopy combined with ICSF baseline correction method and exploratory analysis methodology DPLS classification can be potentially used for distinguishing the banned food additives in field of food safety. PMID:25300041

  14. Georgia's Surface-Water Resources and Streamflow Monitoring Network, 2008

    USGS Publications Warehouse

    ,

    2008-01-01

    Surface water provides 5 billion gallons per day, or 78 percent, of the total freshwater used (including thermoelectric) in Georgia (Fanning, 2003). Climate, geology, and landforms control the natural distribution of Georgia's water resources. Georgia is a 'headwaters' State, with most of the rivers beginning in northern Georgia and increasing in size downstream (see map at right for major watersheds). Surface water is the primary source of water in the northern one-half of the State, including the Atlanta metropolitan area, where limited ground-water resources are difficult to obtain. In Georgia, periodic droughts exacerbate competition for surface-water supplies. Many areas of Georgia also face a threat of flooding because of spring frontal thunderstorms and the potential for hurricanes from both the Atlantic Ocean and Gulf of Mexico. As the population of Georgia increases, these flood risks will increase with development in flood-risk zones, particularly in the coastal region.

  15. Measurements of Water Surface Snow Lines in Classical Protoplanetary Disks

    NASA Astrophysics Data System (ADS)

    Blevins, Sandra M.; Pontoppidan, Klaus M.; Banzatti, Andrea; Zhang, Ke; Najita, Joan R.; Carr, John S.; Salyk, Colette; Blake, Geoffrey A.

    2016-02-01

    We present deep Herschel-PACS spectroscopy of far-infrared water lines from a sample of four protoplanetary disks around solar-mass stars, selected to have strong water emission at mid-infrared wavelengths. By combining the new Herschel spectra with archival Spitzer-IRS spectroscopy, we retrieve a parameterized radial surface water vapor distribution from 0.1 to 100 au using two-dimensional dust and line radiative transfer modeling. The surface water distribution is modeled with a step model composed of a constant inner and outer relative water abundance and a critical radius at which the surface water abundance is allowed to change. We find that the four disks have critical radii of ˜3-11 au, at which the surface water abundance decreases by at least 5 orders of magnitude. The measured values for the critical radius are consistently smaller than the location of the surface snow line, as predicted by the observed spectral energy distribution. This suggests that the sharp drop-off of the surface water abundance is not solely due to the local gas-solid balance, but may also be driven by the deactivation of gas-phase chemical pathways to water below 300 K. Assuming a canonical gas-to-dust ratio of 100, as well as coupled gas and dust temperatures Tgas = Tdust, the best-fit inner water abundances become implausibly high (0.01-1.0 {{{{H}}}2}-1). Conversely, a model in which the gas and dust temperatures are decoupled leads to canonical inner-disk water abundances of ˜ {10}-4 {{{H}}}2-1, while retaining gas-to-dust ratios of 100. That is, the evidence for gas-dust decoupling in disk surfaces is stronger than for enhanced gas-to-dust ratios.

  16. Summary of surface-water quality, ground-water quality, and water withdrawals for the Spirit Lake Reservation, North Dakota

    USGS Publications Warehouse

    Vining, Kevin C.; Cates, Steven W.

    2006-01-01

    Available surface-water quality, ground-water quality, and water-withdrawal data for the Spirit Lake Reservation were summarized. The data were collected intermittently from 1948 through 2004 and were compiled from U.S. Geological Survey databases, North Dakota State Water Commission databases, and Spirit Lake Nation tribal agencies. Although the quality of surface water on the reservation generally is satisfactory, no surface-water sources are used for consumable water supplies. Ground water on the reservation is of sufficient quality for most uses. The Tokio and Warwick aquifers have better overall water quality than the Spiritwood aquifer. Water from the Spiritwood aquifer is used mostly for irrigation. The Warwick aquifer provides most of the consumable water for the reservation and for the city of Devils Lake. Annual water withdrawals from the Warwick aquifer by the Spirit Lake Nation ranged from 71 million gallons to 122 million gallons during 2000-04.

  17. Use of ready-mixed concrete plant sludge water in concrete containing an additive or admixture.

    PubMed

    Chatveera, B; Lertwattanaruk, P

    2009-04-01

    In this study, we investigated the feasibility of using sludge water from a ready-mixed concrete plant as mixing water in concrete containing either fly ash as an additive or a superplasticizer admixture based on sulfonated naphthalene-formaldehyde condensates (SNF). The chemical and physical properties of the sludge water and the dry sludge were investigated. Cement pastes were mixed using sludge water containing various levels of total solids content (0.5, 2.5, 5, 7.5, 10, 12.5, and 15%) in order to determine the optimum content in the sludge water. Increasing the total solids content beyond 5-6% tended to reduce the compressive strength and shorten the setting time. Concrete mixes were then prepared using sludge water containing 5-6% total solids content. The concrete samples were evaluated with regard to water required, setting time, slump, compressive strength, permeability, and resistance to acid attack. The use of sludge water in the concrete mix tended to reduce the effect of both fly ash and superplasticizer. Sludge water with a total solids content of less than 6% is suitable for use in the production of concrete with acceptable strength and durability.

  18. Dynamic effect of sodium-water reaction in fast flux test facility power addition sodium pipes

    SciTech Connect

    Huang, S.N.; Anderson, M.J.

    1990-03-01

    The Fast Flux Facility (FFTF) is a demonstration and test facility of the sodium-cooled fast breeder reactor. A power addition'' to the facility is being considered to convert some of the dumped, unused heat into electricity generation. Components and piping systems to be added are sodium-water steam generators, sodium loop extensions from existing dump heat exchangers to sodium-water steam generators, and conventional water/steam loops. The sodium loops can be subjected to the dynamic loadings of pressure pulses that are caused by postulated sodium leaks and subsequent sodium-water reaction in the steam generator. The existing FFTF secondary pipes and the new power addition sodium loops were evaluated for exposure to the dynamic effect of the sodium-water reaction. Elastic and simplified inelastic dynamic analyses were used in this feasibility study. The results indicate that both the maximum strain and strain range are within the allowable limits. Several cycles of the sodium-water reaction can be sustained by the sodium pipes that are supported by ordinary pipe supports and seismic restraints. Expensive axial pipe restraints to withstand the sodium-water reaction loads are not needed, because the pressure-pulse-induced alternating bending stresses act as secondary stresses and the pressure pulse dynamic effect is a deformation-controlled quantity and is self-limiting. 14 refs., 7 figs., 3 tabs.

  19. Investigation of surface water behavior during glaze ice accretion

    NASA Technical Reports Server (NTRS)

    Hansman, R. John, Jr.; Turnock, Stephen R.

    1988-01-01

    Microvideo observations of glaze ice accretions on 1-in-diameter cylinders in a closed-loop refrigerated wind tunnel were obtained to study factors controlling the behavior of unfrozen surface water during glaze ice accretion. Three zones of surface water behavior were noted, each with a characteristic roughness. The effect of substrate thermal and roughness properties on ice accretions was also studied. The contact angle and hysteresis were found to increase sharply at temperatures just below 0 C, explaining the high resistance to motion of water beads observed on accreting glaze ice surfaces. Based on the results, a simple multizone modification to the current glaze ice accretion model is proposed.

  20. Deep Groundwater Contributions to Surface Water in a Mountainous Watershed

    NASA Astrophysics Data System (ADS)

    Tolley, D. G.; Harding, J. J.; Wilson, J. L.; Frisbee, M. D.

    2012-12-01

    With growing concerns about declining snowpack, warmer temperatures, and land use changes, it is becoming increasingly important to determine the sources that contribute to surface water. In western states, such as New Mexico, most of the surface water is derived from mountainous watersheds. However, the interaction between the groundwater and the surface water within these mountain systems is poorly understood. Geochemical data collected from a mesoscale (~200 km2) watershed in northern New Mexico indicate there may be significant groundwater contributions to the surface water that have largely been ignored in previous studies. Stable isotopic analysis of δ18O and δ2H and Piper diagrams for surface water, groundwater, and spring water are not geochemically distinct. Surface water solute concentrations for most constituents increase as a function of the drainage area while the stable isotopic signature remains constant, suggesting that the water is sourced from similar areas but has undergone differing degrees of geochemical evolution along different flow paths. Plots of SiO2 vs Ca2+, Na+, Mg2+, and K+ show evidence of spatial evolution of groundwater with solute concentrations from the headwaters to the watershed outlet. We hypothesize that the increasing solute concentrations in the surface water are controlled by inputs from deep, more geochemically evolved groundwater. This is similar to what Frisbee et al. (2011) saw in the Saguache Watershed, though our watershed is significantly smaller and has a different geological setting. Due to the chemical kinetics involved, this more geochemically evolved groundwater would require longer residence time along a given flow path to achieve the observed chemical compositions. Significant contributions of old groundwater to surface water could result in the surface water system having increased buffering capacity against climate change. This deep groundwater component in watersheds has largely been unexplored. Our

  1. Surface waters of Kansas, 1895-1919

    USGS Publications Warehouse

    Rice, R.C.

    1921-01-01

    The collection of long-time records of stream-flow in Kansas which is published in this volume has been prepared for the use of those who are concerned with the different phases of the utilization of water in the state.

  2. Third Stokes parameter emission from a periodic water surface

    NASA Technical Reports Server (NTRS)

    Johnson, J. T.; Kong, J. A.; Shin, R. T.; Staelin, D. H.; Oneill, K.; Lohanick, A.

    1991-01-01

    An experiment in which the third Stokes parameter thermal emission from a periodic water surface was measured is documented. This parameter is shown to be related to the direction of periodicity of the periodic surface and to approach brightnesses of up to 30 K at X band for the surface used in the experiment. The surface actually analyzed was a 'two-layer' periodic surface; the theory of thermal emission from such a surface is derived and the theoretical results are found to be in good agreement with the experimental measurements. These results further the idea of using the third Stokes parameter emission as an indicator of wind direction over the ocean.

  3. Groundwater-surface water interactions in fractured Mediterranean mountain environments

    NASA Astrophysics Data System (ADS)

    Eliades, Marinos; Bruggeman, Adriana; Lange, Manfred A.

    2014-05-01

    Groundwater and surface-water systems interact in a variety of geological, morphological, and climatic settings. Vegetation also plays a key role in these interactions as it transfers water from the subsurface and groundwater table towards the surface, where it is redistributed by plants and trees in different soil depths. Cyprus is at the drier end of the precipitation spectrum of the Mediterranean region and has intense seasonal variations in precipitation with frequent droughts. In order to confront water scarcity issues and improve water management plans in the future, we need to obtain a better understanding of the groundwater and surface-water interactions and quantify the hydrological processes in this complex fractured Mediterranean mountain environment. The upstream and midstream of Peristerona watershed was selected as the study area (77 km2). It is a forested mountain watershed with steep slopes (mean 22o) and elevation varying from 417 to 1543 m. The main formations in the area are lower and upper pillow lavas, basalt, diabase and gabbro. From a hydrogeological point of view the upstream area consists mainly of heavily fractured intrusive formations that can hold groundwater inside the fractured zones and in some areas it consists of plutonic rocks with springs. The midstream area is dominated by volcanics with submarine pillow lavas. To assess the surface and groundwater interactions a nested watershed approach will be followed with the synthesis and collation of hydrometric data through a dense monitoring network. Continuous measurements of rainfall, runoff and groundwater levels will be taken. Watershed characteristics will be processed in GIS environment. Also measurements of environmental stable isotopes (O18and H2) will be taken. In addition sap flow instruments will be installed in Pinus brutia species among with soil moisture sensors. Results will quantify the water uptake by trees (Pinus Brutia sp.) and the hydraulic redistribution back to the

  4. Micro-Plasma Transferred Arc Additive Manufacturing for Die and Mold Surface Remanufacturing

    NASA Astrophysics Data System (ADS)

    Jhavar, Suyog; Paul, Christ Prakash; Jain, Neelesh Kumar

    2016-07-01

    Micro-plasma transferred arc ( µPTA) additive manufacturing is one of the newest options for remanufacturing of dies and molds surfaces in the near-millimeter range leading to extended usage of the same. We deployed an automatic micro-plasma deposition setup to deposit a wire of 300 µm of AISI P20 tool steel on the substrate of same material for the potential application in remanufacturing of the die and mold surface. Our present research effort is to establish µPTA additive manufacturing as a viable economical and cleaner methodology for potential industrial applications. We undertook the optimization of single weld bead geometry as the first step in our present study. Bead-on-plate trials were conducted to deposit single bead geometry at various processing parameters. The bead geometry (shape and size) and dilution were measured and the parametric dependence was derived. A set of parameters leading to reproducible regular and smooth single bead geometry were identified and used to prepare a thin wall for mechanical testing. The deposits were subjected to material characterization such as microscopic studies, micro-hardness measurements and tensile testing. The process was compared qualitatively with other deposition processes involving high-energy density beams and was found to be advantageous in terms of low initial and running costs with comparable properties. The outcome of the study confirmed the process capability of µPTA deposition leading to deployment of cost-effective and environmentally friendlier technology for die and mold remanufacturing.

  5. Safety assessment of greenhouse hydroponic tomatoes irrigated with reclaimed and surface water.

    PubMed

    Lopez-Galvez, Francisco; Allende, Ana; Pedrero-Salcedo, Francisco; Alarcon, Juan Jose; Gil, Maria Isabel

    2014-11-17

    The impact of reclaimed and surface water on the microbiological safety of hydroponic tomatoes was assessed. Greenhouse tomatoes were irrigated with reclaimed and surface water and grown on two hydroponic substrates (coconut fiber and rock wool). Water samples (n=208) were taken from irrigation water, with and without the addition of fertilizers and drainage water, and hydroponic tomatoes (n=72). Samples were analyzed for indicator microorganisms, generic Escherichia coli and Listeria spp., and pathogenic bacteria such as Salmonella spp. and Shiga-toxigenic E. coli (STEC), using multiplex real-time PCR (RT-PCR) after enrichment. The correlation between climatological parameters such as temperature and the levels of microorganisms in water samples was also determined. In irrigation water, generic E. coli counts were higher in reclaimed than in surface water whereas Listeria spp. numbers increased after adding the fertilizers in both water sources. In drainage water, no clear differences in E. coli and Listeria numbers were observed between reclaimed and surface water. No positive samples for STEC were found in irrigation water. Presumptive positives for Salmonella spp. were found in 7.7% of the water samples and 62.5% of these samples were reclaimed water. Salmonella-positive samples by RT-PCR could not be confirmed by conventional methods. Higher concentrations of E. coli were associated with Salmonella-presumptive positive samples. Climatological parameters, such as temperature, were not correlated with the E. coli and Listeria spp. counts. Tomato samples were negative for bacterial pathogens, while generic E. coli and Listeria spp. counts were below the detection limit. The prevalence of presumptive Salmonella spp. found in irrigation water (reclaimed and surface water) was high, which might present a risk of contamination. The absence of pathogens on greenhouse hydroponic tomatoes indicates that good agricultural practices (GAP) were in place, avoiding the

  6. Safety assessment of greenhouse hydroponic tomatoes irrigated with reclaimed and surface water.

    PubMed

    Lopez-Galvez, Francisco; Allende, Ana; Pedrero-Salcedo, Francisco; Alarcon, Juan Jose; Gil, Maria Isabel

    2014-11-17

    The impact of reclaimed and surface water on the microbiological safety of hydroponic tomatoes was assessed. Greenhouse tomatoes were irrigated with reclaimed and surface water and grown on two hydroponic substrates (coconut fiber and rock wool). Water samples (n=208) were taken from irrigation water, with and without the addition of fertilizers and drainage water, and hydroponic tomatoes (n=72). Samples were analyzed for indicator microorganisms, generic Escherichia coli and Listeria spp., and pathogenic bacteria such as Salmonella spp. and Shiga-toxigenic E. coli (STEC), using multiplex real-time PCR (RT-PCR) after enrichment. The correlation between climatological parameters such as temperature and the levels of microorganisms in water samples was also determined. In irrigation water, generic E. coli counts were higher in reclaimed than in surface water whereas Listeria spp. numbers increased after adding the fertilizers in both water sources. In drainage water, no clear differences in E. coli and Listeria numbers were observed between reclaimed and surface water. No positive samples for STEC were found in irrigation water. Presumptive positives for Salmonella spp. were found in 7.7% of the water samples and 62.5% of these samples were reclaimed water. Salmonella-positive samples by RT-PCR could not be confirmed by conventional methods. Higher concentrations of E. coli were associated with Salmonella-presumptive positive samples. Climatological parameters, such as temperature, were not correlated with the E. coli and Listeria spp. counts. Tomato samples were negative for bacterial pathogens, while generic E. coli and Listeria spp. counts were below the detection limit. The prevalence of presumptive Salmonella spp. found in irrigation water (reclaimed and surface water) was high, which might present a risk of contamination. The absence of pathogens on greenhouse hydroponic tomatoes indicates that good agricultural practices (GAP) were in place, avoiding the

  7. The potential application of red mud and soil mixture as additive to the surface layer of a landfill cover system.

    PubMed

    Ujaczki, Éva; Feigl, Viktória; Molnár, Mónika; Vaszita, Emese; Uzinger, Nikolett; Erdélyi, Attila; Gruiz, Katalin

    2016-06-01

    Red mud, the by-product of aluminum production, has been regarded as a problematic residue all over the world. Its storage involves risks as evidenced by the Ajka red mud spill, an accident in Hungary where the slurry broke free, flooding the surrounding areas. As an immediate remediation measure more than 5cm thick red mud layer was removed from the flooded soil surface. The removed red mud and soil mixture (RMSM) was transferred into the reservoirs for storage. In this paper the application of RMSM is evaluated in a field study aiming at re-utilizing waste, decreasing cost of waste disposal and providing a value-added product. The purpose was to investigate the applicability of RMSM as surface layer component of landfill cover systems. The field study was carried out in two steps: in lysimeters and in field plots. The RMSM was mixed at ratios ranging between 0 and 50% w/w with low quality subsoil (LQS) originally used as surface layer of an interim landfill cover. The characteristics of the LQS+RMSM mixtures compared to the subsoil (LQS) and the RMSM were determined by physical-chemical, biological and ecotoxicological methods. The addition of RMSM to the subsoil (LQS) at up to 20% did not result any ecotoxic effect, but it increased the water holding capacity. In addition, the microbial substrate utilization became about triple of subsoil (LQS) after 10months. According to our results the RMSM mixed into subsoil (LQS) at 20% w/w dose may be applied as surface layer of landfill cover systems. PMID:27266315

  8. Additive surface complexation modeling of uranium(VI) adsorption onto quartz-sand dominated sediments.

    PubMed

    Dong, Wenming; Wan, Jiamin

    2014-06-17

    Many aquifers contaminated by U(VI)-containing acidic plumes are composed predominantly of quartz-sand sediments. The F-Area of the Savannah River Site (SRS) in South Carolina (USA) is an example. To predict U(VI) mobility and natural attenuation, we conducted U(VI) adsorption experiments using the F-Area plume sediments and reference quartz, goethite, and kaolinite. The sediments are composed of ∼96% quartz-sand and 3-4% fine fractions of kaolinite and goethite. We developed a new humic acid adsorption method for determining the relative surface area abundances of goethite and kaolinite in the fine fractions. This method is expected to be applicable to many other binary mineral pairs, and allows successful application of the component additivity (CA) approach based surface complexation modeling (SCM) at the SRS F-Area and other similar aquifers. Our experimental results indicate that quartz has stronger U(VI) adsorption ability per unit surface area than goethite and kaolinite at pH ≤ 4.0. Our modeling results indicate that the binary (goethite/kaolinite) CA-SCM under-predicts U(VI) adsorption to the quartz-sand dominated sediments at pH ≤ 4.0. The new ternary (quartz/goethite/kaolinite) CA-SCM provides excellent predictions. The contributions of quartz-sand, kaolinite, and goethite to U(VI) adsorption and the potential influences of dissolved Al, Si, and Fe are also discussed.

  9. Boundary slip of superoleophilic, oleophobic, and superoleophobic surfaces immersed in deionized water, hexadecane, and ethylene glycol.

    PubMed

    Jing, Dalei; Bhushan, Bharat

    2013-11-26

    The boundary slip condition is an important property, and its existence can reduce fluid drag in micro/nanofluidic systems. The boundary slip on various surfaces immersed in water and various electrolytes has been widely studied. For the surfaces immersed in oil, the boundary slip on superoleophilic and oleophilic surfaces has been studied, but there is no data on oleophobic and superoleophobic surfaces. In this paper, experiments are carried out to study electrostatic force and boundary slip on superoleophilic, oleophobic, and superoleophobic surfaces immersed in deionized (DI) water, hexadecane, and ethylene glycol. In addition, the surface charge density of the samples immersed in DI water is quantified. Results show that the electrostatic force and the absolute value of the surface charge density of an octadecyltrichlorosilane surface are larger than that of a polystyrene surface, and the electrostatic force and the absolute value of surface charge density of a superoleophilic surface are larger than that of oleophobic and superoleophobic surfaces. For the same liquid, the larger contact angle leads to a larger slip length at the solid-liquid interface. For the same surface, the larger liquid viscosity leads to a larger slip length. The relevant mechanisms are discussed in this paper. PMID:24168076

  10. Boundary slip of superoleophilic, oleophobic, and superoleophobic surfaces immersed in deionized water, hexadecane, and ethylene glycol.

    PubMed

    Jing, Dalei; Bhushan, Bharat

    2013-11-26

    The boundary slip condition is an important property, and its existence can reduce fluid drag in micro/nanofluidic systems. The boundary slip on various surfaces immersed in water and various electrolytes has been widely studied. For the surfaces immersed in oil, the boundary slip on superoleophilic and oleophilic surfaces has been studied, but there is no data on oleophobic and superoleophobic surfaces. In this paper, experiments are carried out to study electrostatic force and boundary slip on superoleophilic, oleophobic, and superoleophobic surfaces immersed in deionized (DI) water, hexadecane, and ethylene glycol. In addition, the surface charge density of the samples immersed in DI water is quantified. Results show that the electrostatic force and the absolute value of the surface charge density of an octadecyltrichlorosilane surface are larger than that of a polystyrene surface, and the electrostatic force and the absolute value of surface charge density of a superoleophilic surface are larger than that of oleophobic and superoleophobic surfaces. For the same liquid, the larger contact angle leads to a larger slip length at the solid-liquid interface. For the same surface, the larger liquid viscosity leads to a larger slip length. The relevant mechanisms are discussed in this paper.

  11. Anomalously rapid hydration water diffusion dynamics near DNA surfaces

    PubMed Central

    Franck, John M.; Ding, Yuan; Stone, Katherine

    2015-01-01

    The emerging Overhauser effect Dynamic Nuclear Polarization (ODNP) technique measures the translational mobility of water within the vicinity (5-15 Å) of preselected sites. The work presented here expands the capabilities of the ODNP technique and illuminates an important, previously unseen, property of the translational diffusion dynamics of water at the surface of DNA duplexes. We attach nitroxide radicals (i.e., spin labels) to multiple phosphate backbone positions of DNA duplexes, allowing ODNP to measure the hydration dynamics at select positions along the DNA surface. With a novel approach to ODNP analysis, we isolate the contributions of water molecules at these sites that undergo free translational diffusion from water molecules that either loosely bind to or exchange protons with the DNA. The results reveal that a significant population of water in a localized volume adjacent to the DNA surface exhibits fast, bulk-like characteristics and moves unusually rapidly compared to water found in similar probe volumes near protein and membrane surfaces. Control studies show that the observation of these characteristics are upheld even when the DNA duplex is tethered to streptavidin or the mobility of the nitroxides is altered. This implies that, as compared to protein or lipid surfaces, it is an intrinsic feature of the DNA duplex surface that it interacts only weakly with a significant fraction of a network of surface hydration water. The displacement of this translationally mobile water is energetically less costly than that of more strongly bound water by up to several kBT and thus can lower the activation barrier for interactions involving the DNA surface. PMID:26256693

  12. Anomalously Rapid Hydration Water Diffusion Dynamics Near DNA Surfaces.

    PubMed

    Franck, John M; Ding, Yuan; Stone, Katherine; Qin, Peter Z; Han, Songi

    2015-09-23

    The emerging Overhauser effect dynamic nuclear polarization (ODNP) technique measures the translational mobility of water within the vicinity (5-15 Å) of preselected sites. The work presented here expands the capabilities of the ODNP technique and illuminates an important, previously unseen, property of the translational diffusion dynamics of water at the surface of DNA duplexes. We attach nitroxide radicals (i.e., spin labels) to multiple phosphate backbone positions of DNA duplexes, allowing ODNP to measure the hydration dynamics at select positions along the DNA surface. With a novel approach to ODNP analysis, we isolate the contributions of water molecules at these sites that undergo free translational diffusion from water molecules that either loosely bind to or exchange protons with the DNA. The results reveal that a significant population of water in a localized volume adjacent to the DNA surface exhibits fast, bulk-like characteristics and moves unusually rapidly compared to water found in similar probe volumes near protein and membrane surfaces. Control studies show that the observation of these characteristics are upheld even when the DNA duplex is tethered to streptavidin or the mobility of the nitroxides is altered. This implies that, as compared to protein or lipid surfaces, it is an intrinsic feature of the DNA duplex surface that it interacts only weakly with a significant fraction of the surface hydration water network. The displacement of this translationally mobile water is energetically less costly than that of more strongly bound water by up to several kBT and thus can lower the activation barrier for interactions involving the DNA surface.

  13. Antibacterial Behavior of Additively Manufactured Porous Titanium with Nanotubular Surfaces Releasing Silver Ions.

    PubMed

    Amin Yavari, S; Loozen, L; Paganelli, F L; Bakhshandeh, S; Lietaert, K; Groot, J A; Fluit, A C; Boel, C H E; Alblas, J; Vogely, H C; Weinans, H; Zadpoor, A A

    2016-07-13

    Additive manufacturing (3D printing) has enabled fabrication of geometrically complex and fully interconnected porous biomaterials with huge surface areas that could be used for biofunctionalization to achieve multifunctional biomaterials. Covering the huge surface area of such porous titanium with nanotubes has been already shown to result in improved bone regeneration performance and implant fixation. In this study, we loaded TiO2 nanotubes with silver antimicrobial agents to equip them with an additional biofunctionality, i.e., antimicrobial behavior. An optimized anodizing protocol was used to create nanotubes on the entire surface area of direct metal printed porous titanium scaffolds. The nanotubes were then loaded by soaking them in three different concentrations (i.e., 0.02, 0.1, and 0.5 M) of AgNO3 solution. The antimicrobial behavior and cell viability of the developed biomaterials were assessed. As far as the early time points (i.e., up to 1 day) are concerned, the biomaterials were found to be extremely effective in preventing biofilm formation and decreasing the number of planktonic bacteria particularly for the middle and high concentrations of silver ions. Interestingly, nanotubes not loaded with antimicrobial agents also showed significantly smaller numbers of adherent bacteria at day 1, which may be attributed to the bactericidal effect of high aspect ratio nanotopographies. The specimens with the highest concentrations of antimicrobial agents adversely affected cell viability at day 1, but this effect is expected to decrease or disappear in the following days as the rate of release of silver ions was observed to markedly decrease within the next few days. The antimicrobial effects of the biomaterials, particularly the ones with the middle and high concentrations of antimicrobial agents, continued until 2 weeks. The potency of the developed biomaterials in decreasing the number of planktonic bacteria and hindering the formation of biofilms make

  14. Field calibration of surface: a model of agricultural chemicals in surface waters.

    PubMed

    Gustafson, D I

    1990-10-01

    Agricultural chemicals sporadically occur at detectable levels in the surface waters of intensively farmed watersheds. HSPF, a previously released model of agricultural chemicals in surface water, had been used to predict concentrations which were much higher (10 X) than those actually observed during monitoring studies. A new model, SURFACE, is described here which is much simpler than HSPF and gives better predictions of surface water concentrations. SURFACE uses PRZM, an EPA model, to calculate edge-of-field runoff losses and simple hydraulic routing algorithms to determine concentrations at the bottom of large river basins. In water systems sampled during 1985 and 1986, SURFACE predictions of annualized mean concentrations for alachlor, atrazine, cyanazine and metolachlor were within 0.09 ppb half of the time.

  15. Two-dimensional percolation at the free water surface and its relation with the surface tension anomaly of water.

    PubMed

    Sega, Marcello; Horvai, George; Jedlovszky, Pál

    2014-08-01

    The percolation temperature of the lateral hydrogen bonding network of the molecules at the free water surface is determined by means of molecular dynamics computer simulation and identification of the truly interfacial molecules analysis for six different water models, including three, four, and five site ones. The results reveal that the lateral percolation temperature coincides with the point where the temperature derivative of the surface tension has a minimum. Hence, the anomalous temperature dependence of the water surface tension is explained by this percolation transition. It is also found that the hydrogen bonding structure of the water surface is largely model-independent at the percolation threshold; the molecules have, on average, 1.90 ± 0.07 hydrogen bonded surface neighbors. The distribution of the molecules according to the number of their hydrogen bonded neighbors at the percolation threshold also agrees very well for all the water models considered. Hydrogen bonding at the water surface can be well described in terms of the random bond percolation model, namely, by the assumptions that (i) every surface water molecule can form up to 3 hydrogen bonds with its lateral neighbors and (ii) the formation of these hydrogen bonds occurs independently from each other. PMID:25106600

  16. Two-dimensional percolation at the free water surface and its relation with the surface tension anomaly of water.

    PubMed

    Sega, Marcello; Horvai, George; Jedlovszky, Pál

    2014-08-01

    The percolation temperature of the lateral hydrogen bonding network of the molecules at the free water surface is determined by means of molecular dynamics computer simulation and identification of the truly interfacial molecules analysis for six different water models, including three, four, and five site ones. The results reveal that the lateral percolation temperature coincides with the point where the temperature derivative of the surface tension has a minimum. Hence, the anomalous temperature dependence of the water surface tension is explained by this percolation transition. It is also found that the hydrogen bonding structure of the water surface is largely model-independent at the percolation threshold; the molecules have, on average, 1.90 ± 0.07 hydrogen bonded surface neighbors. The distribution of the molecules according to the number of their hydrogen bonded neighbors at the percolation threshold also agrees very well for all the water models considered. Hydrogen bonding at the water surface can be well described in terms of the random bond percolation model, namely, by the assumptions that (i) every surface water molecule can form up to 3 hydrogen bonds with its lateral neighbors and (ii) the formation of these hydrogen bonds occurs independently from each other.

  17. Groundwater and surface-water utilisation using a bank infiltration technique in Malaysia

    NASA Astrophysics Data System (ADS)

    Shamsuddin, Mohd Khairul Nizar; Sulaiman, Wan Nor Azmin; Suratman, Saim; Zakaria, Mohamad Pauzi; Samuding, Kamarudin

    2014-05-01

    Bank infiltration (BI) is one of the solutions to providing raw water for public supply in tropical countries. This study in Malaysia explores the use of BI to supplement a polluted surface-water resource with groundwater. Three major factors were investigated: (1) contribution of surface water through BI to the resulting abstraction, (2) input of local groundwater, and (3) water-quality characteristics of the resulting water supply. A geophysical method was employed to define the subsurface geology and hydrogeology, and isotope techniques were performed to identify the source of groundwater recharge and the interaction between surface water and groundwater. The physicochemical and microbiological parameters of the local surface-water bodies and groundwater were analyzed before and during water abstraction. Extracted water revealed a 5-98 % decrease in turbidity, as well as reductions in HCO3 -, Cl-, SO4 2-, NO3 -, Ca2+, Al3+ and As concentrations compared with those of Langat River water. In addition, amounts of E. coli, total coliform and Giardia were significantly reduced (99.9 %). However, water samples from test wells during pumping showed high concentrations of Fe2+ and Mn2+. Pumping test results indicate that the two wells used in the study were able to sustain yields.

  18. Phosphorus removal with membrane filtration for surface water treatment.

    PubMed

    Dietze, A; Gnirss, R; Wiesmann, U

    2002-01-01

    Surface waters are often burdened with inflows of low quality water, so that drinking-water production, swimming or ground water charging must be restricted. To ensure the long-term use of such surface water it is necessary to treat the influents or the water used for ground water charging. The current treatment process for phosphorus and turbidity removal is a process combination called floc filtration. By using this conventional method it is possible to reduce the dissolved ortho-phosphate and the turbidity (particulate phosphorus) as well as the amounts of algae and pathogenic organisms to very low concentrations. The high degree of reduction is only achieved by a relatively high dosage of chemicals. A comparison will be made between this process, which represents the state-of-the-art, and the combination of precipitation/coagulation with micro-/ultrafiltration in dead-end filtration mode.

  19. Identifying and Mapping Seasonal Surface Water Frost with MGS TES

    NASA Astrophysics Data System (ADS)

    Bapst, J.; Bandfield, J. L.; Wood, S. E.

    2013-12-01

    The Thermal Emission Spectrometer (TES) visible/near-infrared and thermal infrared bolometers measured surface broadband albedo and temperature for more than three Mars years. As seasons progress on Mars, surface temperatures may fall below the frost point of volatiles in the atmosphere (namely, carbon dioxide and water). Systematic mapping of the spatial and temporal occurrence of these volatiles in the martian atmosphere, on the surface, and in the subsurface has shown their importance in understanding the climate of Mars. However, few studies have investigated seasonal surface water frost and its role in the global water cycle. We examine zonally-averaged TES daytime albedo, temperature, and water vapor abundance data [after Smith, 2004] to map the presence of surface water frost on Mars. Surface water frost occurs in the polar and mid latitudes, in regions with surface temperatures less than 220 K and above 150 K, and can significantly increase albedo relative to the bare surface. In the northern hemisphere water frost is most apparent in late fall/early winter, before the onset of carbon dioxide frost. Dust storms occurring near northern winter solstice affect albedo data and prevent us from putting a latitudinal lower limit on the water frost in the northern hemisphere. Regardless, seasonal water frost occurs at least as low as 48°N in Utopia Planitia, beginning at Ls=~230°, as observed by Viking Lander 2 [Svitek and Murray, 1990]. Daytime surface water frost was also observed at the Phoenix Lander site (68°N) beginning at Ls=~160° [Cull et al., 2010]. The timing of albedo variations observed by TES agree relatively well with lander observations of seasonal frost. Seasonal water frost is not detected during fall in the southern hemisphere. A potential explanation for this discrepancy, compared with frost detections in the north, is the disparity in atmospheric water vapor abundance between the two hemispheres. The frost point temperatures for water vapor

  20. Precipitation of salt in saline water drop on superhydrophobic surface

    NASA Astrophysics Data System (ADS)

    Shin, Bongsu; Moon, Myoung-Woon; Kim, Ho-Young

    2012-11-01

    In the membrane distillation process, water vapor of heated, pressurized saline water is transported across the membrane to be collected as pure water. While the water-repellency of the membrane surface has been considered an important parameter affecting the distillation efficiency, the resistance of the membrane to the contamination due to salt has gathered little scientific interest thus far. Here we experimentally investigate the precipitation of salt in sessile saline water drops, to find drastic differences in salt crystallization behavior depending on the water-repellency of solid surface. On a moderately hydrophobic surface with a static contact angle with water being about 150 degrees, salt crystals are aligned and stacked along the initial contact line, forming an interesting structure resembling an igloo. On a superhydrophobic surface with about 164 degrees of static contact angle with water, salt crystallizes only at the center of the drop-solid contact area, forming a pebble-shaped structure. We explain this difference by comparing the evaporation modes (constant contact radius versus constant contact angle) of the sessile drops on those surfaces. We also visualize the liquid flow within drops undergoing evaporation and precipitation at the same time using PIV.

  1. Exposure and risk assessment of zinc in Japanese surface waters.

    PubMed

    Naito, Wataru; Kamo, Masashi; Tsushima, Koji; Iwasaki, Yuichi

    2010-09-15

    In recent years, due to concerns on the potential effects of zinc on aquatic biota, zinc is receiving particular attention from regulatory agencies. A comprehensive exposure and risk assessment of zinc in Japanese surface waters was conducted to provide a scientific basis for developing realistic risk reduction measures for zinc. Emissions from corrosion contribute approximately 37% of the total zinc emissions to surface water in Japan. The zinc concentration distributions estimated using 12 years of monitoring data from 2075 sites by a maximum likelihood method indicated that the mean concentrations have gradually declined. The threshold concentrations (HC5 and PHC5) derived from organism- and population-level species sensitivity distributions were estimated to be 27 and 107 microg/L for total zinc, respectively. The risk characterization identified that during 1991-2002, 14.5-26.8% of the monitoring sites likely exceeded the HC5, whereas only 0.7-3.5% likely exceeded the PHC5. Evaluation of the effect of stormwater runoff to zinc concentrations in a river showed that zinc concentrations in river water increased significantly from roadway drainage flowing into the river. The cost-effectiveness analyses demonstrated that enforcement of the zinc national effluent standard may be effective at a certain level for public water areas in Japan; however, the degree of the effectiveness is highly dependent on the characteristics (e.g., sources and background) of the watersheds. An emissions and exposure assessment along with cost-effectiveness analysis is crucial for developing realistic and appropriate ecological risk management of zinc. The zinc RAD in Japan illustrated that in any "state-of-the science" method used, some degree of ecological risk from zinc can be observed in some Japanese water environments. On the other hand, zinc is a beneficial material for human industrial activities. Because zinc is an element, its role in industrial activities would be difficult

  2. Surface Propensities of the Self-Ions of Water

    PubMed Central

    2016-01-01

    The surface charge of water, which is important in a wide range of chemical, biological, material, and environmental contexts, has been a subject of lengthy and heated debate. Recently, it has been shown that the highly efficient LEWIS force field, in which semiclassical, independently mobile valence electron pairs capture the amphiproticity, polarizability and H-bonding of water, provides an excellent description of the solvation and dynamics of hydroxide and hydronium in bulk water. Here we turn our attention to slabs, cylinders, and droplets. In extended simulations with 1000 molecules, we find that hydroxide consistently prefers the surface, hydronium consistently avoids the surface, and the two together form an electrical double layer until neutralization occurs. The behavior of hydroxide can largely be accounted for by the observation that hydroxide moving to the surface loses fewer hydrogen bonds than are gained by the water molecule that it displaces from the surface. At the same time, since the orientation of the hydroxide increases the ratio of dangling hydrogens to dangling lone pairs, the proton activity of the exposed surface may be increased, rather than decreased. Hydroxide also moves more rapidly in the surface than in the bulk, likely because the proton donating propensity of neighboring water molecules is focused on the one hydrogen that is not dangling from the surface. PMID:27163053

  3. Effect of dilute polymer additives on the acoustic cavitation threshold of water

    SciTech Connect

    Crum, L.A.; Brosey, J.E.

    1984-02-01

    Measurements are presented of the variation of the acoustic cavitation threshold of water with concentration of the polymer additives polyethylene oxide and guar gum. It was found that small amounts of these additives could significantly increase the cavitation threshold. A theoretical model, based upon nucleation of a gas bubble from a Harvey-type crevice in a mote or solid particle, is developed that gives good agreement with the measurements. The applicability of this approach to an explanation of cavitation index reduction in flow-generated or confined jet cavitation, when polymer additives are introduced, is discussed.

  4. 78 FR 42692 - Food Additives Permitted in Feed and Drinking Water of Animals; Ammonium Formate

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-17

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration 21 CFR Part 573 Food Additives Permitted in Feed and Drinking Water of Animals; Ammonium Formate AGENCY: Food and Drug Administration, HHS. ACTION: Final...

  5. Releasing-addition method for the flame-photometric determination of calcium in thermal waters

    USGS Publications Warehouse

    Rowe, J.J.

    1963-01-01

    Study of the interferences of silica and sulfate in the flame-photometric determination of calcium in thermal waters has led to the development of a method requiring no prior chemical separations. The interference effects of silica, sulfate, potassium, sodium, aluminum, and phosphate are overcome by an addition technique coupled with the use of magnesium as a releasing agent. ?? 1963.

  6. An addition at the C-terminus of water-buffalo immunoglobin lambda chains.

    PubMed

    Svasti, J

    1977-01-01

    The amino acid sequence of the C-terminal tryptic peptide of pooled water-buffalo immunoglobulin lambda chains was determined as Thr-Val-Lys-Pro-Ser-Glu-Cys-Pro-Ser. This sequence is closely homologous to equivalent sequences from other species, but shows an additional amino acid on the C-terminal side of the interchain half-cystine residue.

  7. Chloride in ground water and surface water in the vicinity of selected surface-water sampling sites of the beneficial use monitoring program of Oklahoma, 2003

    USGS Publications Warehouse

    Mashburn, Shana L.; Sughru, Michael P.

    2004-01-01

    The Oklahoma Water Resources Board Beneficial Use Monitoring Program reported exceedances of beneficial-use standards for chloride at 11 surface-water sampling sites from January to October 2002. The U.S. Geological Survey, in cooperation with the Oklahoma Department of Environmental Quality, conducted a study to determine the chloride concentrations in ground water in the vicinity of Beneficial Use Monitoring Program surface-water sampling sites not meeting beneficial use standards for chloride and compare chloride concentrations in ground water and surface water. The chloride-impaired Beneficial Use Monitoring Program surface-water sampling sites are located in the western and southern regions of Oklahoma. The ground-water sampling sites were placed in proximity to the 11 surface-water sampling sites designated impaired by chloride by the Oklahoma Water Resources Board. Two surface-water sampling sites were located on the Beaver River (headwaters of the North Canadian River), three sites on the Cimarron River, one site on Sandy Creek, one site on North Fork Red River, and four sites on the Red River. Six ground-water samples were collected, when possible, from two test holes located upstream from each of the 11 Beneficial Use Monitoring Program surface-water sampling sites. One test hole was placed on the left bank and right bank, when possible, of each Beneficial Use Monitoring Program surfacewater sampling site. All test holes were located on alluvial deposits adjacent to the Beneficial Use Monitoring Program surface-water sampling sites within 0.5 mile of the stream. Top, middle, and bottom ground-water samples were collected from the alluvium at each test hole, when possible. Water properties of specific conductance, pH, water temperature, and dissolved oxygen were recorded in the field before sampling for chloride. The ground-water median chloride concentrations at 8 of the 11 Beneficial Use Monitoring Program sites were less than the surface-water median

  8. A siphon gage for monitoring surface-water levels

    USGS Publications Warehouse

    McCobb, T.D.; LeBlanc, D.R.; Socolow, R.S.

    1999-01-01

    A device that uses a siphon tube to establish a hydraulic connection between the bottom of an onshore standpipe and a point at the bottom of a water body was designed and tested for monitoring surface-water levels. Water is added to the standpipe to a level sufficient to drive a complete slug of water through the siphoning tube and to flush all air out of the system. The water levels in the standpipe and the water body equilibrate and provide a measurable static water surface in the standpipe. The siphon gage was designed to allow quick and accurate year-round measurements with minimal maintenance. Currently available devices for monitoring surface-water levels commonly involve time-consuming and costly installation and surveying, and the movement of reference points and the presence of ice cover in cold regions cause discontinuity and inaccuracy in the data collected. Installation and field testing of a siphon gage using 0.75-in-diameter polyethylene tubing at Ashumet Pond in Falmouth, Massachusetts, demonstrated that the siphon gage can provide long-term data with a field effort and accuracy equivalent to measurement of ground-water levels at an observation well.A device that uses a siphon tube to establish a hydraulic connection between the bottom of an onshore standpipe and a point at the bottom of a water body was designed and tested for monitoring surface-water levels. Water is added to the standpipe to a level sufficient to drive a complete slug of water through the siphoning tube and to flush all air out of the system. The water levels in the standpipe and the water body equilibrate and provide a measurable static water surface in the standpipe. The siphon gage was designed to allow quick and accurate year-round measurements with minimal maintenance. Currently available devices for monitoring surface-water levels commonly involve time-consuming and costly installation and surveying, and the movement of reference points and the presence of ice cover in cold

  9. Study of stability and thermodynamic properties of water-in-diesel nanoemulsion fuels with nano-Al additive

    NASA Astrophysics Data System (ADS)

    Mehta, Rakhi N.; More, Utkarsh; Malek, Naved; Chakraborty, Mousumi; Parikh, Parimal A.

    2015-11-01

    The present work addresses the formation of water-in-diesel (W/D) nanoemulsion by blending different percentages of water along with nano-Al additive in various propositions to enhance the combustion characteristics. The roles of various surfactants such as Sorbitan monooleate (Span 80), Triton X-100, Tetradecyltrimethylammonium bromide, and newly synthesized and characterized dicationic surfactants were discussed based upon their ability to stabilize the nanoemulsions. Surface active properties of the surfactants were determined by measuring their interfacial tension and subsequently by measuring the critical micelle concentration of the surfactants. Triton X-100 was found to be the most efficient surfactant for the current water-in-diesel nanoemulsion as it stabilized the suspensions for more than 8 h. Particle size analysis proved emulsion size to be in the order of nanometer, and zeta potential values were found to have neutral behavior at water-diesel interface. Experimental studies confirmed that that blends W/D [1 % (vol.) water] and W/DA [1 % (vol.) water, 0.1 % (wt.) nano-Al] were thermodynamically stable.

  10. Tracer injection techniques in flowing surface water

    NASA Astrophysics Data System (ADS)

    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

  11. Aerobic methane production in surface waters of the Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Finke, N.; Crespo-Medina, M.; Schweers, J.; Joye, S. B.

    2011-12-01

    Near surface water of the global oceans often show elevated methane concentrations compared to the water column below with concentrations in supersaturation in regard to the atmosphere (Lamontagne et al. 1973), resulting in a source of this potent greenhouse gas to the atmosphere. The mechanisms leading to methane supersaturation in surface waters remains unclear. Incubations with Trichodesmium-containing Pacific surface water suggested methylphosphonate as potential methane precursor under phosphate limiting conditions (Karl et al. 2008), whereas in phosphate rich Arctic surface waters, DMSP addition stimulated methane production (Damm et al. 2010). Surface waters of the Gulf of Mexico typically exhibit a methane maximum that is conincident with the deep chlorophyll maximum, below the depths where Trichodesmium is abundant. Addition of methylphosphonate, dimethylsulfoniopropionate (DMSP) or methane thiol (MeSH), the proposed methane precursor in DMSP conversion to methane, to oxic sea water did not affect methane production within the chlorophyll maximum at most stations, whereas methyl phosphonate addition stimulated methane production in the surface water and proposed deep Trichodesmium horizon. Pre-filtration of the water through a 10 μm sieve, which eliminated Trichodesmium, or through a 1.2 μm filter, which eliminated additional cyanobacteria such as Synechococcus, did not reduce methane production. Under dark oxic and dark anoxic conditions, however, methane production was reduced 5 and 7-20 fold, respectively, indicating that anerobic methane production in anoxic microniches is not responsible for the methane production. The reduction of methane production under dark conditions suggests that methane production is, in some yet unrecognized way, linked to phototrophic metabolism. Cyanobacteria are likely not responsible for the observed aerobic methane production in the surface waters of the Gulf of Mexico and while methylphosphonate is a potential

  12. ICESat-derived inland water surface spot heights

    NASA Astrophysics Data System (ADS)

    O'Loughlin, Fiachra E.; Neal, Jeffrey; Yamazaki, Dai; Bates, Paul D.

    2016-04-01

    Accurate measurement of water surface height is key to many fields in hydrology and limnology. Satellite radar and laser altimetry have been shown to be useful means of obtaining such data where no ground gauging stations exist, and the accuracy of different satellite instruments is now reasonably well understood. Past validation studies have shown water surface height data from the ICESat instrument to have the highest vertical accuracy (mean absolute errors of ˜10 cm for ICESat, compared, for example, with ˜28 cm from Envisat), yet no freely available source of processed ICESat data currently exists for inland water bodies. Here we present a database of processed and quality checked ICESat-derived inland water surface heights (IWSH) for water bodies greater than 3 arc sec (˜92 m at the equator) in width. Four automated methods for removing spurious observations or outliers were investigated, along with the impact of using different water masks. We find that the best performing method ensures that observations used are completely surrounded by water in the SRTM Water Body data. Using this method for removing spurious observations, we estimate transect-averaged water surface heights at 587,292 unique locations from 2003 to 2009, with the number of locations proportional to the size of the river.

  13. Passive water control at the surface of a superhydrophobic lichen.

    PubMed

    Hamlett, Christopher A E; Shirtcliffe, Neil James; Pyatt, F Brian; Newton, Michael I; McHale, Glen; Koch, Kerstin

    2011-12-01

    Some lichens have a super-hydrophobic upper surface, which repels water drops, keeping the surface dry but probably preventing water uptake. Spore ejection requires water and is most efficient just after rainfall. This study was carried out to investigate how super-hydrophobic lichens manage water uptake and repellence at their fruiting bodies, or podetia. Drops of water were placed onto separate podetia of Cladonia chlorophaea and observed using optical microscopy and cryo-scanning-electron microscopy (cryo-SEM) techniques to determine the structure of podetia and to visualise their interaction with water droplets. SEM and optical microscopy studies revealed that the surface of the podetia was constructed in a three-level structural hierarchy. By cryo-SEM of water-glycerol droplets placed on the upper part of the podetium, pinning of the droplet to specific, hydrophilic spots (pycnidia/apothecia) was observed. The results suggest a mechanism for water uptake, which is highly sophisticated, using surface wettability to generate a passive response to different types of precipitation in a manner similar to the Namib Desert beetle. This mechanism is likely to be found in other organisms as it offers passive but selective water control.

  14. EMAP - surface waters monitoring and research strategy. Fiscal Year 1991

    SciTech Connect

    Paulsen, S.G.; Larsen, D.P.; Kaufmann, P.R.; Whittier, T.R.; Baker, J.R.

    1991-03-01

    The document describes the Environmental Monitoring and Assessment Program's (EMAP) vision of what is needed to evaluate the ecological condition of the surface waters of the United States. It describes the content and organization of the research plan.

  15. Second Inflection Point of the Surface Tension of Water

    NASA Astrophysics Data System (ADS)

    Kalova, Jana; Mares, Radim

    2012-06-01

    The theme of a second inflection point of the temperature dependence of the surface tension of water remains a subject of controversy. Using data above 273 K, it is difficult to get a proof of existence of the second inflection point, because of experimental uncertainties. Data for the surface tension of supercooled water and results of a molecular dynamics study were included into the exploration of existence of an inflection point. A new term was included into the IAPWS equation to describe the surface tension in the supercooled water region. The new equation describes the surface tension values of ordinary water between 228 K and 647 K and leads to the inflection point value at a temperature of about 1.5 °C.

  16. Wave-Generated Flows on the Water Surface

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

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

  17. Reassigning the most stable surface of hydroxyapatite to the water resistant hydroxyl terminated (010) surface

    NASA Astrophysics Data System (ADS)

    Zeglinski, Jacek; Nolan, Michael; Thompson, Damien; Tofail, Syed A. M.

    2014-05-01

    Understanding the surface stability and crystal growth morphology of hydroxyapatite is important to comprehend bone growth and repair processes and to engineer protein adsorption, cellular adhesion and biomineralization on calcium phosphate based bone grafts and implant coatings. It has generally been assumed from electronic structure calculations that the most stable hydroxyapatite surface is the (001) surface, terminated just above hydroxyl ions perpendicular to the {001} crystal plane. However, this is inconsistent with the known preferential growth direction of hydroxyapatite crystals and previous experimental work which indicates that, contrary to currently accepted theoretical predictions, it is actually the (010) surface that is preferentially exposed. The surface structure of the (010) face is still debated and needs reconciliation. In this work, we use a large set of density functional theory calculations to model the interaction of water with hydroxyapatite surfaces and probe the surface stability and resistance to hydrolytic remodeling of a range of surface faces including the (001) surface and the phosphate-exposed, calcium-exposed, and hydroxyl-exposed terminations of the (010) surface. For the (001) surface and the phosphate-exposed (010) surface, dissociative water adsorption is favorable. In contrast, the hydroxyl-terminated (010) surface will not split water and only molecular adsorption of water is possible. Our calculations show, overall, that the hydroxyl-terminated (010) surface is the most stable and thus should be the predominant form of the hydroxyapatite surface exposed in experiments. This finding reconciles discrepancies between the currently proposed surface terminations of hydroxyapatite and the experimentally observed crystal growth direction and surface stability, which may aid efforts to accelerate biomineralization and better control bone-repair processes on hydroxyapatite surfaces.

  18. The biological impact of landfill leachate on nearby surface water

    SciTech Connect

    Geis, S.W.

    1994-12-31

    Five landfill sites were evaluated for their potential to adversely impact the biotic community of surface waters. Acute and chronic aquatic toxicity tests were used to determine the toxicity of water samples collected from landfill monitoring wells and the nearest surface water. Four of the five landfill sites exhibited acute or chronic toxicity to Ceriodaphnia dubia, Daphnia magna, or Pimephales promelas. Toxicity identification procedures performed on water samples revealed toxic responses to metals and one toxic response to organic compounds. Surface water toxicity at an industrial landfill is most likely due to zinc from a tire production facility. Iron and a surfactant were determined to be the probable causes for toxicity at two municipal solid waste landfills.

  19. Screening and human health risk assessment of pharmaceuticals and their transformation products in Dutch surface waters and drinking water.

    PubMed

    de Jongh, Cindy M; Kooij, Pascal J F; de Voogt, Pim; ter Laak, Thomas L

    2012-06-15

    Numerous studies describe the presence of pharmaceuticals in the water cycle, while their transformation products are usually not included. In the current study 17 common pharmaceuticals and 9 transformation products were monitored in the Dutch waters, including surface waters, pre-treated surface waters, river bank filtrates, two groundwater samples affected by surface water and drinking waters. In these samples, 12 pharmaceuticals and 7 transformation products were present. Concentrations were generally highest in surface waters, intermediate in treated surface waters and river bank filtrates and lowest or not detected in produced drinking water. However, the concentrations of phenazone and its environmental transformation product AMPH were significantly higher in river bank filtrates, which is likely due to historical contamination. Fairly constant ratios were observed between concentrations of transformation products and parent pharmaceuticals. This might enable prediction of concentrations of transformation products from concentrations of parent pharmaceuticals. The toxicological relevance of the observed pharmaceuticals and transformation products was assessed by deriving (i) a substance specific provisional guideline value (pGLV) and (ii) a group pGLV for groups of related compounds were under the assumption of additivity of effects within each group. A substantial margin exists between the maximum summed concentrations of these compounds present in different water types and the derived (group) pGLVs. Based on the results of this limited screening campaign no adverse health effects of the studied compounds are expected in (sources of) drinking water in the Netherlands. The presence of transformation products with similar pharmacological activities and concentration levels as their parents illustrates the relevance of monitoring transformation products, and including these in risk assessment. More thorough monitoring yielding information on statistical

  20. Intermolecular Casimir-Polder forces in water and near surfaces.

    PubMed

    Thiyam, Priyadarshini; Persson, Clas; Sernelius, Bo E; Parsons, Drew F; Malthe-Sørenssen, Anders; Boström, Mathias

    2014-09-01

    The Casimir-Polder force is an important long-range interaction involved in adsorption and desorption of molecules in fluids. We explore Casimir-Polder interactions between methane molecules in water, and between a molecule in water near SiO(2) and hexane surfaces. Inclusion of the finite molecular size in the expression for the Casimir-Polder energy leads to estimates of the dispersion contribution to the binding energies between molecules and between one molecule and a planar surface.

  1. Odour and flavour thresholds of gasoline additives (MTBE, ETBE and TAME) and their occurrence in Dutch drinking water collection areas.

    PubMed

    van Wezel, Annemarie; Puijker, Leo; Vink, Cees; Versteegh, Ans; de Voogt, Pim

    2009-07-01

    The use of ETBE (ethyl-tert-butylether) as gasoline additive has recently grown rapidly. Contamination of aquatic systems is well documented for MTBE (methyl-tert-butylether), but less for other gasoline additives. Due to their mobility they may easily reach drinking water collection areas. Odour and flavour thresholds of MTBE are known to be low, but for ETBE and TAME (methyl-tert-amylether) hardly information is available. The objective here is to determine these thresholds for MTBE, ETBE and TAME, and relate these to concentrations monitored in thousands of samples from Dutch drinking water collection areas. For ETBE odour and flavour thresholds are low with 1-2microgL(-1), for MTBE and TAME they range from 7 to 16microg L(-1). In most groundwater collection areas MTBE concentrations are below 0.1microg L(-1). In phreatic groundwaters in sandy soils not covered by a protective soil layer, occasionally MTBE occurs at higher concentrations. For surface water collection areas a minority of the locations is free of MTBE. For river bank and dune infiltrates, at a few locations the odour and flavour threshold is exceeded. For ETBE fewer monitoring data are available. ETBE was found in 2 out of 37 groundwater collection areas, in concentrations below 1microgL(-1). In the surface water collection areas monitored ETBE was found in concentrations near to the odour and flavour thresholds. The low odour and flavour thresholds combined with the high mobility and persistence of these compounds, their high production volumes and their increased use may yield problems with future production of drinking water.

  2. Protocol for quantitative tracing of surface water with synthetic DNA

    NASA Astrophysics Data System (ADS)

    Foppen, J. W.; Bogaard, T. A.

    2012-04-01

    Based on experiments we carried out in 2010 with various synthetic single stranded DNA markers with a size of 80 nucleotides (ssDNA; Foppen et al., 2011), we concluded that ssDNA can be used to carry out spatially distributed multi-tracer experiments in the environment. Main advantages are in principle unlimited amount of tracers, environmental friendly and tracer recovery at very high dilution rates (detection limit is very low). However, when ssDNA was injected in headwater streams, we found that at selected downstream locations, the total mass recovery was less than 100%. The exact reason for low mass recovery was unknown. In order to start identifying the cause of the loss of mass in these surface waters, and to increase our knowledge of the behaviour of synthetic ssDNA in the environment, we examined the effect of laboratory and field protocols working with artificial DNA by performing numerous batch experiments. Then, we carried out several field tests in different headwater streams in the Netherlands and in Luxembourg. The laboratory experiments consisted of a batch of water in a vessel with in the order of 10^10 ssDNA molecules injected into the batch. The total duration of each experiment was 10 hour, and, at regular time intervals, 100 µl samples were collected in a 1.5 ml Eppendorf vial for qPCR analyses. The waters we used ranged from milliQ water to river water with an Electrical Conductivity of around 400 μS/cm. The batch experiments were performed in different vessel types: polyethylene bottles, polypropylene copolymer bottles , and glass bottles. In addition, two filter types were tested: 1 µm pore size glass fibre filters and 0.2 µm pore size cellulose acetate filters. Lastly, stream bed sediment was added to the batch experiments to quantify interaction of the DNA with sediment. For each field experiment around 10^15 ssDNA molecules were injected, and water samples were collected 100 - 600 m downstream of the point of injection. Additionally

  3. Dropwise condensation rate of water breath figures on polymer surfaces having similar surface free energies

    NASA Astrophysics Data System (ADS)

    Ucar, Ikrime O.; Erbil, H. Yildirim

    2012-10-01

    This study investigates the effect of surface roughness, wettability, water contact angle hysteresis (CAH) and wetting hysteresis (WH) of polymeric substrates to the water drop condensation rate. We used five polyolefin coatings whose surface free energies were in a close range of 30-37 mJ/m2 but having different surface roughness and CAH. The formation of water breath figures was monitored at a temperature just below the dew point. The initial number of the condensed droplets per unit area (N0) and droplet surface coverage were determined during the early stage of drop condensation where the droplet coalescence was negligible. It was found that the mean drop diameter of condensed droplets on these polymer surfaces grow according to a power law with exponent 1/3 of time, similar to the previous reports given in the literature. It was determined that surface roughness and corresponding CAH and WH properties of polymers have important effects on the number of nucleation sites and growth rate of the condensed water droplets. N0 values and the surface coverage increased with the increase in surface roughness, CAH and WH of the polymer surfaces. The total condensed water drop volume also increased with the increase in surface roughness in accordance with the increase of the number of nucleated droplets.

  4. Modeling Studies of Geothermal Systems with a Free Water Surface

    SciTech Connect

    Bodvarsson, Gudmundur S.; Pruess, K.

    1983-12-15

    Numerical simulators developed for geothermal reservoir engineering applications generally only consider systems which are saturated with liquid water and/or steam. However, most geothermal fields are in hydraulic communicatino with shallow ground water aquifers having free surface (water level), so that production or injection operations will cause movement of the surface, and of the air in the pore spaces above the water level. In some geothermal fields the water level is located hundreds of meters below the surface (e.g. Olkaria, Kenya; Bjornsson, 1978), so that an extensive so that an extensive unsaturated zone is present. In other the caprock may be very leaky or nonexistent [e.g., Klamath Falls, oregon (Sammel, 1976)]; Cerro Prieto, Mexico; (Grant et al., 1984) in which case ther eis good hydraulic communication between the geothermal reservoir and the shallow unconfined aquifers. Thus, there is a need to explore the effect of shallow free-surface aquifers on reservoir behavior during production or injection operations. In a free-surface aquifer the water table moves depending upon the rate of recharge or discharge. This results in a high overall storativity; typically two orders of magnitude higher than that of compressed liquid systems, but one or two orders of magnitude lower than that for liquid-steam reservoirs. As a consequence, various data analysis methods developed for compressed liquid aquifers (such as conventional well test analysis methods) are not applicable to aquifer with a free surface.

  5. Chlorine stress mediates microbial surface attachment in drinking water systems.

    PubMed

    Liu, Li; Le, Yang; Jin, Juliang; Zhou, Yuliang; Chen, Guowei

    2015-03-01

    Microbial attachment to drinking water pipe surfaces facilitates pathogen survival and deteriorates disinfection performance, directly threatening the safety of drinking water. Notwithstanding that the formation of biofilm has been studied for decades, the underlying mechanisms for the origins of microbial surface attachment in biofilm development in drinking water pipelines remain largely elusive. We combined experimental and mathematical methods to investigate the role of environmental stress-mediated cell motility on microbial surface attachment in chlorination-stressed drinking water distribution systems. Results show that at low levels of disinfectant (0.0-1.0 mg/L), the presence of chlorine promotes initiation of microbial surface attachment, while higher amounts of disinfectant (>1.0 mg/L) inhibit microbial attachment. The proposed mathematical model further demonstrates that chlorination stress (0.0-5.0 mg/L)-mediated microbial cell motility regulates the frequency of cell-wall collision and thereby controls initial microbial surface attachment. The results reveal that transport processes and decay patterns of chlorine in drinking water pipelines regulate microbial cell motility and, thus, control initial surface cell attachment. It provides a mechanistic understanding of microbial attachment shaped by environmental disinfection stress and leads to new insights into microbial safety protocols in water distribution systems.

  6. Occurrence of deeethylatrazine and deisopropylatrazine in surface and ground water

    SciTech Connect

    Thurman, E.M.; Goolsby, D.A.

    1996-10-01

    Field-disappearance studies and a regional study of nine rivers in the Midwest show that deethylatrazine (DEA) and deisopropylatrazine (DIA) occur frequently in surface water that has received runoff from two parent triazine herbicides, atrazine and cyanazine. The concentration of DEA and DIA in surface water varies with the hydrologic conditions of the basin and the timing of runoff, with maximum concentrations reaching 5 mg/L (DEA + DIA). Early rainfall followed by a dry summer will result in an early peak concentration of metabolites in surface water. A wet summer will delay the maximum concentrations of metabolites and increase their runoff into surface water, occasionally resulting in a slight separation of the parent atrazine maximum concentrations from the metabolite maximum concentrations giving a {open_quotes}second flush{close_quotes} of triazine metabolites to surface water. Replicated field dissipation studies of atrazine and cyanazine indicate that DIA/DEA ratios will vary from 0.4{plus_minus}0.1 when atrazine is the major triazine present to 0.6{plus_minus}0.1 when significant amounts of cyanazine are present. A comparison of transport time of DEA and DIA from field plots to their appearance in surface water indicates that storage and dilution are occurring in the alluvial aquifers of the basin.

  7. Formation and transport of deethylatrazine and deisopropylatrazine in surface water

    USGS Publications Warehouse

    Thurman, E.M.; Meyer, M.T.; Mills, M.S.; Zimmerman, L.R.; Perry, C.A.; Goolsby, D.A.

    1994-01-01

    Field disappearance studies and a regional study of nine rivers in the Midwest Corn Belt show that deethylatrazine (DEA; 2-amino-4-chloro-6-isopropylamino-s-triazine) and deisopropylatrazine (DIA; 2-amino-4-chloro-6-ethylaminos-triazine) occur frequently in surface water that has received runoff from two parent triazine herbicides, atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) and cyanazine (2-chloro-4-ethylamino-6-methylpropionitrileamino-s-triazine). The concentration of DEA and DIA in surface water varies with the hydrologic conditions of the basin and the timing of runoff, with maximum concentrations reaching 5 ??g/L (DEA + DIA). Early rainfall followed by a dry summer will result in an early peak concentration of metabolites in surface water. A wet summer will delay the maximum concentrations of metabolites and increase their runoff into surface water, occasionally resulting in a slight separation of the parent atrazine maximum concentrations from the metabolite maximum concentrations, giving a "second flush?? of triazine metabolites to surface water. Replicated field dissipation studies of atrazine and cyanazine indicate that DIA/DEA ratios will vary from 0.4 ?? 0.1 when atrazine is the major triazine present to 0.6 ?? 0.1 when significant amounts of cyanazine are present. A comparison of transport time of DEA and DIA from field plots to their appearance in surface water indicates that storage and dilution are occurring in the alluvial aquifers of the basin.

  8. Stabilization of solid-supported phospholipid multilayer against water by gramicidin addition.

    PubMed

    Han, Won Bae; Kim, Yongdeok; An, Hyeun Hwan; Kim, Hee-Soo; Yoon, Chong Seung

    2014-03-20

    It was demonstrated that hydrophobicity of solid supported planar dipalmitoyl phosphatidylcholine (DPPC) phospholipid multilayer can be greatly increased by incorporating a transmembrane protein, gramicidin, into the DPPC membrane. The contact angle of deionized water droplet on the gramicidin-modified DPPC membrane increased from 0° (complete wetting) without gramicidin to 55° after adding 15 mol % gramicidin. The increased hydrophobicity of the gramicidin-modified DPPC membrane allowed the membrane to remain stable at the air/water interface as well as underwater. The Au nanoparticles deposited on the gramicidin-modified DPPC membrane reproduced the characteristic surface plasmon resonance peak after being kept underwater or in phosphate-buffered saline solution for 5 days, attesting to the membrane stability in an aqueous environment. The enhanced underwater stability of the lipid multilayer substantially broadens the potential application of the lipid multilayer which includes biosensing, enzymatic fuel cell, surface enhanced Raman spectroscopy substrate.

  9. Variation of Local Surface Properties of an Air Bubble in Water Caused by Its Interaction with Another Surface.

    PubMed

    Del Castillo, Lorena A; Ohnishi, Satomi; Carnie, Steven L; Horn, Roger G

    2016-08-01

    Surface and hydrodynamic forces acting between an air bubble and a flat mica surface in surfactant-free water and in 1 mM KCl solution have been investigated by observing film drainage using a modified surface force apparatus (SFA). The bubble shapes observed with the SFA are compared to theoretical profiles computed from a model that considers hydrodynamic interactions, surface curvature, and disjoining pressure arising from electrical double layer and van der Waals interactions. It is shown that the bubble experiences double-layer forces, and a final equilibrium wetting film between the bubble and mica surfaces is formed by van der Waals repulsion. However, comparison with the theoretical model reveals that the double-layer forces are not simply a function of surface separation. Rather, they appear to be changed by one of more of the following: the bubble's dynamic deformation, its proximity to another surface, and/or hydrodynamic flow in the aqueous film that separate them. The same comments apply to the hydrodynamic mobility or immobility of the air-water interface. Together the results show that the bubble's surface is "soft" in two senses: in addition to its well-known deformability, its local properties are affected by weak external forces, in this case the electrical double-layer interactions with a nearby surface and hydrodynamic flow in the neighboring aqueous phase. PMID:27391417

  10. The Use of Additional GPS Frequencies to Independently Determine Tropospheric Water Vapor Profiles

    NASA Technical Reports Server (NTRS)

    Herman, B.M.; Feng, D.; Flittner, D. E.; Kursinski, E. R.

    2000-01-01

    It is well known that the currently employed L1 and L2 GPS/MET frequencies (1.2 - 1.6) Ghz) do not allow for the separation of water vapor and density (or temperature) from active microwave occultation measurements in regions of the troposphere warmer than 240 K Therefore, additional information must be used, from other types of measurements and weather analyses, to recover water vapor (and temperature) profiles. Thus in data sparse regions, these inferred profiles can be subject to larger errors than would result in data rich regions. The use of properly selected additional GPS frequencies enables a direct, independent measurement of the absorption associated with the water vapor profile, which may then be used in the standard GPS/MET retrievals to obtain a more accurate determination of atmospheric temperature throughout the water vapor layer. This study looks at the use of microwave crosslinks in the region of the 22 Ghz water vapor absorption line for this purpose. An added advantage of using 22 Ghz frequencies is that they are only negligibly affected by the ionosphere in contrast to the large effect at the GPS frequencies. The retrieval algorithm uses both amplitude and phase measurements to obtain profiles of atmospheric pressure, temperature and water water vapor pressure with a vertical resolution of 1 km or better. This technique also provides the cloud liquid water content along the ray path, which is in itself an important element in climate monitoring. Advantages of this method include the ability to make measurements in the presence of clouds and the use of techniques and technology proven through the GPS/MET experiment and several of NASA's planetary exploration missions. Simulations demonstrating this method will be presented for both clear and cloudy sky conditions.

  11. Highly treated mine waters may require major ion addition before environmental release.

    PubMed

    Harford, Andrew J; Jones, David R; van Dam, Rick A

    2013-01-15

    Mining operations often use passive and/or active water treatments to improve water quality prior to environmental release. Key considerations in choosing a treatment process include the extent to which the water quality is actually improved, and the potential residual environmental risks of the release of such water. However, there are few published studies concerning the environmental impacts of treated waste waters. This study used toxicity identification evaluation (TIE) methods to quantify and identify the "toxic" constituents of a highly-treated water (distillate) produced by brine concentration of a mining process water. Exposure of five freshwater species (Chlorella sp., Lemna aequinoctialis, Hydra viridissima, Moinodaphnia macleayi and Mogurnda mogurnda) to a concentration range of the distillate (0, 25, 50 and 100%) found that it was toxic to H. viridissima (50-100% effect when exposed to 100% distillate). TIE tests demonstrated that the effect wasn't due to residual ammonia (~1 mg L(-1)N) or trace organics, and unlikely to be due to manganese (Mn; 130-230 μg L(-1)). Conversely, addition of 0.2 and 0.5 mg L(-1) calcium improved the growth rate of H. viridissima by 61 and 66%, respectively, while addition of calcium, sodium and potassium (0.5, 1.0 and 0.4 mg L(-1), respectively) to levels comparable to that in the local aquatic environment resulted in 100% recovery. Further assessment on the likelihood of residual metal toxicity indicated that Mn concentrations in the distillate were at levels that could inhibit the growth of H. viridissima. Ultimately, the results demonstrated that ion deficiency should be considered as a potential stressor in risk/impact assessments of the discharge of treated wastewaters, and these may need to be supplemented with the deficient ions to reduce environmental impacts. The findings have highlighted the need for water managers to consider the possibility of unintended environmental risks from the discharge of highly

  12. Highly treated mine waters may require major ion addition before environmental release.

    PubMed

    Harford, Andrew J; Jones, David R; van Dam, Rick A

    2013-01-15

    Mining operations often use passive and/or active water treatments to improve water quality prior to environmental release. Key considerations in choosing a treatment process include the extent to which the water quality is actually improved, and the potential residual environmental risks of the release of such water. However, there are few published studies concerning the environmental impacts of treated waste waters. This study used toxicity identification evaluation (TIE) methods to quantify and identify the "toxic" constituents of a highly-treated water (distillate) produced by brine concentration of a mining process water. Exposure of five freshwater species (Chlorella sp., Lemna aequinoctialis, Hydra viridissima, Moinodaphnia macleayi and Mogurnda mogurnda) to a concentration range of the distillate (0, 25, 50 and 100%) found that it was toxic to H. viridissima (50-100% effect when exposed to 100% distillate). TIE tests demonstrated that the effect wasn't due to residual ammonia (~1 mg L(-1)N) or trace organics, and unlikely to be due to manganese (Mn; 130-230 μg L(-1)). Conversely, addition of 0.2 and 0.5 mg L(-1) calcium improved the growth rate of H. viridissima by 61 and 66%, respectively, while addition of calcium, sodium and potassium (0.5, 1.0 and 0.4 mg L(-1), respectively) to levels comparable to that in the local aquatic environment resulted in 100% recovery. Further assessment on the likelihood of residual metal toxicity indicated that Mn concentrations in the distillate were at levels that could inhibit the growth of H. viridissima. Ultimately, the results demonstrated that ion deficiency should be considered as a potential stressor in risk/impact assessments of the discharge of treated wastewaters, and these may need to be supplemented with the deficient ions to reduce environmental impacts. The findings have highlighted the need for water managers to consider the possibility of unintended environmental risks from the discharge of highly

  13. High resolution remote sensing of water surface patterns

    NASA Astrophysics Data System (ADS)

    Woodget, A.; Visser, F.; Maddock, I.; Carbonneau, P.

    2012-12-01

    The assessment of in-stream habitat availability within fluvial environments in the UK traditionally includes the mapping of patterns which appear on the surface of the water, known as 'surface flow types' (SFTs). The UK's River Habitat Survey identifies ten key SFTs, including categories such as rippled flow, upwelling, broken standing waves and smooth flow. SFTs result from the interaction between the underlying channel morphology, water depth and velocity and reflect the local flow hydraulics. It has been shown that SFTs can be both biologically and hydraulically distinct. SFT mapping is usually conducted from the river banks where estimates of spatial coverage are made by eye. This approach is affected by user subjectivity and inaccuracies in the spatial extent of mapped units. Remote sensing and specifically the recent developments in unmanned aerial systems (UAS) may now offer an alternative approach for SFT mapping, with the capability for rapid and repeatable collection of very high resolution imagery from low altitudes, under bespoke flight conditions. This PhD research is aimed at investigating the mapping of SFTs using high resolution optical imagery (less than 10cm) collected from a helicopter-based UAS flown at low altitudes (less than 100m). This paper presents the initial findings from a series of structured experiments on the River Arrow, a small lowland river in Warwickshire, UK. These experiments investigate the potential for mapping SFTs from still and video imagery of different spatial resolutions collected at different flying altitudes and from different viewing angles (i.e. vertical and oblique). Imagery is processed using 3D mosaicking software to create orthophotos and digital elevation models (DEM). The types of image analysis which are tested include a simple, manual visual assessment undertaken in a GIS environment, based on the high resolution optical imagery. In addition, an object-based image analysis approach which makes use of the

  14. Evaporation model for beam based additive manufacturing using free surface lattice Boltzmann methods

    NASA Astrophysics Data System (ADS)

    Klassen, Alexander; Scharowsky, Thorsten; Körner, Carolin

    2014-07-01

    Evaporation plays an important role in many technical applications including beam-based additive manufacturing processes, such as selective electron beam or selective laser melting (SEBM/SLM). In this paper, we describe an evaporation model which we employ within the framework of a two-dimensional free surface lattice Boltzmann method. With this method, we solve the hydrodynamics as well as thermodynamics of the molten material taking into account the mass and energy losses due to evaporation and the recoil pressure acting on the melt pool. Validation of the numerical model is performed by measuring maximum melt depths and evaporative losses in samples of pure titanium and Ti-6Al-4V molten by an electron beam. Finally, the model is applied to create processing maps for an SEBM process. The results predict that the penetration depth of the electron beam, which is a function of the acceleration voltage, has a significant influence on evaporation effects.

  15. CHARACTERIZING SURFACE WATERS THAT MAY NOT REQUIRE FILTRATION

    EPA Science Inventory

    Field data from various utilities were studied with the object of identifying a set of characteristics of a surface water that might allow it to be successfully treated by disinfection alone, thus avoiding the need to filter. It was found possible to define water quality standard...

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

    USGS Publications Warehouse

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

    2012-01-01

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

  17. A Black Phosphate Conversion Coating on Steel Surface Using Antimony(III)-Tartrate as an Additive

    NASA Astrophysics Data System (ADS)

    Li, Feng; Wang, Guiping

    2016-05-01

    A novel black phosphate conversion coating was formed on steel surface through a Zn-Mn phosphating bath containing mainly ZnO, H3PO4, Mn(H2PO4)2, and Ca(NO3)2, where antimony(III)-tartrate was used as the blackening agent of phosphatization. The surface morphology and composition of the coating were characterized by scanning electron microscopy, energy dispersion spectroscopy, and x-ray photoelectron spectroscopy. Corrosion resistance of the coating was studied by potentiodynamic polarization curves and electrochemical impedance spectroscopy. The pH value of the solution had significant influence on the formation and corrosion resistance of the coating. The experimental results indicated that the Sb plays a vital role in the blackening of phosphate conversion coating. The optimal concentration of antimony(III)-tartrate in the phosphating bath used in this experiment was 1.0 g L-1, as higher values reduced the corrosion resistance of the coating. In addition, by saponification and oil seals, the corrosion duration of the black phosphate coating in a copper sulfate spot test can be as long as 20 min.

  18. Non-additivity of molecule-surface van der Waals potentials from force measurements

    PubMed Central

    Wagner, Christian; Fournier, Norman; Ruiz, Victor G.; Li, Chen; Müllen, Klaus; Rohlfing, Michael; Tkatchenko, Alexandre; Temirov, Ruslan; Tautz, F. Stefan

    2014-01-01

    Van der Waals (vdW) forces act ubiquitously in condensed matter. Despite being weak on an atomic level, they substantially influence molecular and biological systems due to their long range and system-size scaling. The difficulty to isolate and measure vdW forces on a single-molecule level causes our present understanding to be strongly theory based. Here we show measurements of the attractive potential between differently sized organic molecules and a metal surface using an atomic force microscope. Our choice of molecules and the large molecule-surface separation cause this attraction to be purely of vdW type. The experiment allows testing the asymptotic vdW force law and its validity range. We find a superlinear growth of the vdW attraction with molecular size, originating from the increased deconfinement of electrons in the molecules. Because such non-additive vdW contributions are not accounted for in most first-principles or empirical calculations, we suggest further development in that direction. PMID:25424490

  19. Non-additivity of molecule-surface van der Waals potentials from force measurements.

    PubMed

    Wagner, Christian; Fournier, Norman; Ruiz, Victor G; Li, Chen; Müllen, Klaus; Rohlfing, Michael; Tkatchenko, Alexandre; Temirov, Ruslan; Tautz, F Stefan

    2014-11-26

    Van der Waals (vdW) forces act ubiquitously in condensed matter. Despite being weak on an atomic level, they substantially influence molecular and biological systems due to their long range and system-size scaling. The difficulty to isolate and measure vdW forces on a single-molecule level causes our present understanding to be strongly theory based. Here we show measurements of the attractive potential between differently sized organic molecules and a metal surface using an atomic force microscope. Our choice of molecules and the large molecule-surface separation cause this attraction to be purely of vdW type. The experiment allows testing the asymptotic vdW force law and its validity range. We find a superlinear growth of the vdW attraction with molecular size, originating from the increased deconfinement of electrons in the molecules. Because such non-additive vdW contributions are not accounted for in most first-principles or empirical calculations, we suggest further development in that direction.

  20. Molecular Imprinting of Silica Nanoparticle Surfaces via Reversible Addition-Fragmentation Polymerization for Optical Biosensing Applications

    NASA Astrophysics Data System (ADS)

    Oluz, Zehra; Nayab, Sana; Kursun, Talya Tugana; Caykara, Tuncer; Yameen, Basit; Duran, Hatice

    Azo initiator modified surface of silica nanoparticles were coated via reversible addition-fragmentation polymerization (RAFT) of methacrylic acid and ethylene glycol dimethacrylate using 2-phenylprop 2-yl dithobenzoate as chain transfer agent. Using L-phenylalanine anilide as template during polymerization led molecularly imprinted nanoparticles. RAFT polymerization offers an efficient control of grafting process, while molecularly imprinted polymers shows enhanced capacity as sensor. L-phenylalanine anilide imprinted silica particles were characterized by X-Ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM). Performances of the particles were followed by surface plasmon resonance spectroscopy (SPR) after coating the final product on gold deposited glass substrate against four different analogous of analyte molecules: D-henylalanine anilide, L-tyrosine, L-tryptophan and L-phenylalanine. Characterizations indicated that silica particles coated with polymer layer do contain binding sites for L-phenylalanine anilide, and are highly selective for the molecule of interest. This project was supported by TUBITAK (Project No:112M804).

  1. An Ontology Design Pattern for Surface Water Features

    SciTech Connect

    Sinha, Gaurav; Mark, David; Kolas, Dave; Varanka, Dalia; Romero, Boleslo E; Feng, Chen-Chieh; Usery, Lynn; Liebermann, Joshua; Sorokine, Alexandre

    2014-01-01

    Surface water is a primary concept of human experience but concepts are captured in cultures and languages in many different ways. Still, many commonalities can be found due to the physical basis of many of the properties and categories. An abstract ontology of surface water features based only on those physical properties of landscape features has the best potential for serving as a foundational domain ontology. It can then be used to systematically incor-porate concepts that are specific to a culture, language, or scientific domain. The Surface Water ontology design pattern was developed both for domain knowledge distillation and to serve as a conceptual building-block for more complex surface water ontologies. A fundamental distinction is made in this on-tology between landscape features that act as containers (e.g., stream channels, basins) and the bodies of water (e.g., rivers, lakes) that occupy those containers. Concave (container) landforms semantics are specified in a Dry module and the semantics of contained bodies of water in a Wet module. The pattern is imple-mented in OWL, but Description Logic axioms and a detailed explanation is provided. The OWL ontology will be an important contribution to Semantic Web vocabulary for annotating surface water feature datasets. A discussion about why there is a need to complement the pattern with other ontologies, es-pecially the previously developed Surface Network pattern is also provided. Fi-nally, the practical value of the pattern in semantic querying of surface water datasets is illustrated through a few queries and annotated geospatial datasets.

  2. Earth's surface water change over the past 30 years

    NASA Astrophysics Data System (ADS)

    Donchyts, Gennadii; Baart, Fedor; Winsemius, Hessel; Gorelick, Noel; Kwadijk, Jaap; van de Giesen, Nick

    2016-09-01

    Earth's surface gained 115,000 km2 of water and 173,000 km2 of land over the past 30 years, including 20,135 km2 of water and 33,700 km2 of land in coastal areas. Here, we analyse the gains and losses through the Deltares Aqua Monitor -- an open tool that detects land and water changes around the globe.

  3. Seasonal Spatial Patterns of Surface Water Temperature, Surface Heat Fluxes and Meteorological Forcing Over Lake Geneva

    NASA Astrophysics Data System (ADS)

    Irani Rahaghi, A.; Lemmin, U.; Bouffard, D.; Riffler, M.; Wunderle, S.; Barry, D. A.

    2015-12-01

    In many lakes, surface heat flux (SHF) is the most important component controlling the lake's energy content. Accurate methods for the determination of SHF are valuable for water management, and for use in hydrological and meteorological models. Large lakes, not surprisingly, are subject to spatially and temporally varying meteorological conditions, and hence SHF. Here, we report on an investigation for estimating the SHF of a large European lake, Lake Geneva. We evaluated several bulk formulas to estimate Lake Geneva's SHF based on different data sources. A total of 64 different surface heat flux models were realized using existing representations for different heat flux components. Data sources to run the models included meteorological data (from an operational numerical weather prediction model, COSMO-2) and lake surface water temperature (LSWT, from satellite imagery). Models were calibrated at two points in the lake for which regular depth profiles of temperature are available, and which enabled computation of the total heat content variation. The latter, computed for 03.2008-12.2012, was the metric used to rank the different models. The best calibrated model was then selected to calculate the spatial distribution of SHF. Analysis of the model results shows that evaporative and convective heat fluxes are the dominant terms controlling the spatial pattern of SHF. The former is significant in all seasons while the latter plays a role only in fall and winter. Meteorological observations illustrate that wind-sheltering, and to some extent relative humidity variability, are the main reasons for the observed large-scale spatial variability. In addition, both modeling and satellite observations indicate that, on average, the eastern part of the lake is warmer than the western part, with a greater temperature contrast in spring and summer than in fall and winter whereas the SHF spatial splitting is stronger in fall and winter. This is mainly due to negative heat flux

  4. 10 CFR 60.132 - Additional design criteria for surface facilities in the geologic repository operations area.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... the Geologic Repository Operations Area § 60.132 Additional design criteria for surface facilities in the geologic repository operations area. (a) Facilities for receipt and retrieval of waste. Surface... wastes at the geologic repository operations area, whether these wastes are on the surface...

  5. Effects of ground water exchange on the hydrology and ecology of surface water.

    PubMed

    Hayashi, Masaki; Rosenberry, Donald O

    2002-01-01

    Ground water exchange affects the ecology of surface water by sustaining stream base flow and moderating water-level fluctuations of ground water-fed lakes. It also provides stable-temperature habitats and supplies nutrients and inorganic ions. Ground water input of nutrients can even determine the trophic status of lakes and the distribution of macrophytes. In streams the mixing of ground water and surface water in shallow channel and bankside sediments creates a unique environment called the hyporheic zone, an important component of the lotic ecosystem. Localized areas of high ground water discharge in streams provide thermal refugia for fish. Ground water also provides moisture to riparian vegetation, which in turn supplies organic matter to streams and enhances bank resistance to erosion. As hydrologists and ecologists interact to understand the impact of ground water on aquatic ecology, a new research field called "ecohydrology" is emerging.

  6. Water transport mechanism through open capillaries analyzed by direct surface modifications on biological surfaces.

    PubMed

    Ishii, Daisuke; Horiguchi, Hiroko; Hirai, Yuji; Yabu, Hiroshi; Matsuo, Yasutaka; Ijiro, Kuniharu; Tsujii, Kaoru; Shimozawa, Tateo; Hariyama, Takahiko; Shimomura, Masatsugu

    2013-01-01

    Some small animals only use water transport mechanisms passively driven by surface energies. However, little is known about passive water transport mechanisms because it is difficult to measure the wettability of microstructures in small areas and determine the chemistry of biological surfaces. Herein, we developed to directly analyse the structural effects of wettability of chemically modified biological surfaces by using a nanoliter volume water droplet and a hi-speed video system. The wharf roach Ligia exotica transports water only by using open capillaries in its legs containing hair- and paddle-like microstructures. The structural effects of legs chemically modified with a self-assembled monolayer were analysed, so that the wharf roach has a smart water transport system passively driven by differences of wettability between the microstructures. We anticipate that this passive water transport mechanism may inspire novel biomimetic fluid manipulations with or without a gravitational field. PMID:24149467

  7. Water transport mechanism through open capillaries analyzed by direct surface modifications on biological surfaces

    NASA Astrophysics Data System (ADS)

    Ishii, Daisuke; Horiguchi, Hiroko; Hirai, Yuji; Yabu, Hiroshi; Matsuo, Yasutaka; Ijiro, Kuniharu; Tsujii, Kaoru; Shimozawa, Tateo; Hariyama, Takahiko; Shimomura, Masatsugu

    2013-10-01

    Some small animals only use water transport mechanisms passively driven by surface energies. However, little is known about passive water transport mechanisms because it is difficult to measure the wettability of microstructures in small areas and determine the chemistry of biological surfaces. Herein, we developed to directly analyse the structural effects of wettability of chemically modified biological surfaces by using a nanoliter volume water droplet and a hi-speed video system. The wharf roach Ligia exotica transports water only by using open capillaries in its legs containing hair- and paddle-like microstructures. The structural effects of legs chemically modified with a self-assembled monolayer were analysed, so that the wharf roach has a smart water transport system passively driven by differences of wettability between the microstructures. We anticipate that this passive water transport mechanism may inspire novel biomimetic fluid manipulations with or without a gravitational field.

  8. Role of Carbon-Addition and Hydrogen-Migration Reactions in Soot Surface Growth.

    PubMed

    Zhang, Hong-Bo; Hou, Dingyu; Law, Chung K; You, Xiaoqing

    2016-02-11

    Using density functional theory and master equation modeling, we have studied the kinetics of small unsaturated aliphatic molecules reacting with polycyclic aromatic hydrocarbon (PAH) molecules having a diradical character. We have found that these reactions follow the mechanism of carbon addition and hydrogen migration (CAHM) on both spin-triplet and open-shell singlet potential energy surfaces at a rate that is about ten times those of the hydrogen-abstraction-carbon-addition (HACA) reactions at 1500 K in the fuel-rich postflame region. The results also show that the most active reaction sites are in the center of the zigzag edges of the PAHs. Furthermore, the reaction products are more likely to form straight rather than branched aliphatic side chains in the case of reacting with diacetylene. The computed rate constants are also found to be independent of pressure at conditions of interest in soot formation, and the activation barriers of the CAHM reactions are linearly correlated with the diradical characters.

  9. Role of Carbon-Addition and Hydrogen-Migration Reactions in Soot Surface Growth.

    PubMed

    Zhang, Hong-Bo; Hou, Dingyu; Law, Chung K; You, Xiaoqing

    2016-02-11

    Using density functional theory and master equation modeling, we have studied the kinetics of small unsaturated aliphatic molecules reacting with polycyclic aromatic hydrocarbon (PAH) molecules having a diradical character. We have found that these reactions follow the mechanism of carbon addition and hydrogen migration (CAHM) on both spin-triplet and open-shell singlet potential energy surfaces at a rate that is about ten times those of the hydrogen-abstraction-carbon-addition (HACA) reactions at 1500 K in the fuel-rich postflame region. The results also show that the most active reaction sites are in the center of the zigzag edges of the PAHs. Furthermore, the reaction products are more likely to form straight rather than branched aliphatic side chains in the case of reacting with diacetylene. The computed rate constants are also found to be independent of pressure at conditions of interest in soot formation, and the activation barriers of the CAHM reactions are linearly correlated with the diradical characters. PMID:26799641

  10. Occurrence of Giardia and Cryptosporidium spp. in surface water supplies.

    PubMed Central

    LeChevallier, M W; Norton, W D; Lee, R G

    1991-01-01

    Giardia and Cryptosporidium levels were determined by using a combined immunofluorescence test for source waters of 66 surface water treatment plants in 14 states and 1 Canadian province. The results showed that cysts and oocysts were widely dispersed in the aquatic environment. Giardia spp. were detected in 81% of the raw water samples. Cryptosporidium spp. were found in 87% of the raw water locations. Overall, Giardia or Cryptosporidium spp. were detected in 97% of the raw water samples. Higher cyst and oocyst densities were associated with source waters receiving industrial or sewage effluents. Significant correlations were found between Giardia and Cryptosporidium densities and raw water quality parameters such as turbidity and total and fecal coliform levels. Statistical modeling suggests that cyst and oocyst densities could be predicted on the basis of watershed and water quality characteristics. The occurrence of high levels of Giardia cysts in raw water samples may require water utilities to apply treatment beyond that outlined in the Surface Water Treatment Rule of the U.S. Environmental Protection Agency. PMID:1822675

  11. Profile of the Interface between a Hydrophobic Surface and Water

    NASA Astrophysics Data System (ADS)

    Perez-Salas, Ursula; Stalgren, Johan; Majkrzak, Charles; Heinrich, Frank; Toney, Michael; Vanderah, David

    2008-03-01

    Aqueous interfaces are ubiquitous and play a fundamental role in biology, chemistry, and geology. The structure of water near interfaces is of the utmost importance, including chemical reactivity and macromolecular function. Theoretical work by Chandler et al. on polar-apolar interfaces predicts that a water depletion layer exists between a hydrophobic surface and bulk water for hydrophobes larger than ˜20nm2 (a ˜4A in radius apolar molecule). Until now, what the interface really looks like remains in dispute since recent experiments give conflicting results: from complete wetting (no water depletion layer) to a water depletion layer. Those experiments that have found a water depletion layer report 40-70% water in the depletion zone: 40 -70% and a width of ˜3A. However, an alternative interpretation to the profiles exists where no depletion layer is required. By studying hydrophobic SAM surfaces against several water mixtures we obtained the hydrophobic/water profile by phase sensitive neutron reflectivity. With this model independent technique we observe a 2 times wider and drier depletion water layer: 6A thick and 0-25% water. Given the level of disagreement, I will review the topic of immiscible interfaces and show how phase sensitive reflectometry is unique in obtaining nm resolution profiles without fitting bias.

  12. Evaluation of selected surface-water-quality stations in Wyoming

    USGS Publications Warehouse

    Rucker, S.J.; DeLong, L.L.

    1987-01-01

    The U.S. Geological Survey, in cooperation with the Wyoming Department of Agriculture, has conducted a surface-water-quality program in Wyoming since 1965. The purpose has been to determine the chemical quality of the water in terms of the major dissolved constituents (salinity). Changing agricultural techniques and energy development have stimulated a need for an expanded program involving additional types of data. This report determines the adequacy of the data collected thus far to describe the chemical quality. The sampling program was evaluated by determining how well the data describe the dissolved-solids load of the streams. Monthly mean loads were estimated at 16 stations throughout the network where daily streamflow and daily specific conductance were available. Monthly loads were then compared with loads estimated from daily streamflow and data derived from analyses of samples collected on a monthly basis at these same stations. Agreement was good. Solute-load hydrographs were constructed for 37 stations and from some reaches where streamflow records were available. Because stations where no discharge records are available are not amenable to this type of analysis, data collected at these stations are of limited usefulness. This report covers analyses of data for all qualifying sites in Wyoming except those in the Green River Basin, which were analyzed in U.S. Geological Survey Water Resources Investigations 77-103. The salinity in most of the streams evaluated is adequately described by the data collected. Reduced sampling is feasible, and time and money can be diverted to collecting other data. (USGS)

  13. Investigation of water washes suitable for very small meat plants to reduce pathogens on beef surfaces.

    PubMed

    Yoder, Sally Flowers; Henning, William R; Mills, Edward W; Doores, Stephanie; Ostiguy, Nancy; Cutter, Catherine N

    2010-05-01

    Water washing with a handheld hose was performed on beef surfaces to ascertain the most effective combination of methods needed to remove potentially harmful microorganisms. For these experiments, beef brisket surfaces were experimentally inoculated with a fecal slurry containing Escherichia coli O157:H7, Salmonella Typhimurium, Campylobacter coli, and Campylobacter jejuni. In a pilot study, surfaces were washed with cold water (15 degrees C) at various water pressures, spray distances, application times, and drip times, and remaining bacterial populations were determined following the enumeration and isolation of pathogens and naturally occurring hygiene indicators (mesophilic aerobic bacteria, coliforms, and E. coli). The most efficacious combinations of these washing conditions were applied subsequently to artificially contaminated beef brisket surfaces in conjunction with hot (77 degrees C), warm (54 degrees C), and additional cold (15 degrees C) water washes. In the cold water washing pilot study, combinations of physical washing conditions significantly reduced all bacterial populations (P < 0.05). Further studies clearly indicated the superior bactericidal effectiveness of hot water washing; E. coli O157:H7 and Salmonella Typhimurium were reduced by 3.8 and 4.1 log CFU/cm(2), respectively. Overall, higher water temperature, longer application times, and shorter spray distances more effectively removed pathogens from inoculated beef surfaces. These findings will be used to formulate water washing recommendations for very small meat processing establishments. PMID:20501042

  14. Tensile testing of ultra-thin films on water surface

    NASA Astrophysics Data System (ADS)

    Kim, Jae-Han; Nizami, Adeel; Hwangbo, Yun; Jang, Bongkyun; Lee, Hak-Joo; Woo, Chang-Su; Hyun, Seungmin; Kim, Taek-Soo

    2013-10-01

    The surface of water provides an excellent environment for gliding movement, in both nature and modern technology, from surface living animals such as the water strider, to Langmuir-Blodgett films. The high surface tension of water keeps the contacting objects afloat, and its low viscosity enables almost frictionless sliding on the surface. Here we utilize the water surface as a nearly ideal underlying support for free-standing ultra-thin films and develop a novel tensile testing method for the precise measurement of mechanical properties of the films. In this method, namely, the pseudo free-standing tensile test, all specimen preparation and testing procedures are performed on the water surface, resulting in easy handling and almost frictionless sliding without specimen damage or substrate effects. We further utilize van der Waals adhesion for the damage-free gripping of an ultra-thin film specimen. Our approach can potentially be used to explore the mechanical properties of emerging two-dimensional materials.

  15. Index of surface-water stations in Texas, January 1989

    USGS Publications Warehouse

    Rawson, Jack; Carrillo, E.R.; Buckner, H.D.

    1989-01-01

    As of January 1, 1989, the surface-water data-collection network in Texas included 373 continuous-streamflow, 75 continuous or daily reservoir-content, 37 gage-height, 15 crest-stage partial-record, 200 data collection platform, 7 periodic discharge through range, 27 flood-hydrograph partial-record, 27 low-flow partial-record, 43 daily chemical-quality, 17 continuous-recording water quality, 87 periodic biological, 11 lake survey, 159 period organic and (or) nutrient, 2 periodic insecticide, 28 periodic pesticide, 19 automatic sampler, 137 periodic minor element, 126 periodic chemical-quality, 75 periodic physical organic, 17 continuous-recording temperature, and 29 national stream-gaging accounting network stations. Plate 1 shows the location of surface-water streamflow or reservoir-content and chemical-quality or sediment stations in Texas. Plate 2 shows the location of partial-record surface-water stations. (USGS)

  16. Circumnutation on the water surface: female flowers of Vallisneria

    PubMed Central

    Kosuge, Keiko; Iida, Satoko; Katou, Kiyoshi; Mimura, Tetsuro

    2013-01-01

    Circumnutation, the helical movement of growing organ tips, is ubiquitous in land plants. The mechanisms underlying circumnutation have been debated since Darwin's time. Experiments in space and mutant analyses have revealed that internal oscillatory (tropism-independent) movement and gravitropic response are involved in circumnutation. Female flower buds of tape grass (Vallisneria asiatica var. biwaensis) circumnutate on the water surface. Our observations and experiments with an artificial model indicated that gravitropism is barely involved in circumnutation. Instead, we show that helical intercalary growth at the base of peduncle plays the primary role in all movements in Vallisneria. This growth pattern produces torsional bud rotation, and gravity and buoyancy forces have a physical effect on the direction of peduncle elongation, resulting in bud circumnutation on the water surface. In contrast to other water-pollinated hydrophilous plants, circumnutation in Vallisneria enables female flowers to actively collect male flowers from a larger surface area of water. PMID:23355948

  17. Circumnutation on the water surface: female flowers of Vallisneria.

    PubMed

    Kosuge, Keiko; Iida, Satoko; Katou, Kiyoshi; Mimura, Tetsuro

    2013-01-01

    Circumnutation, the helical movement of growing organ tips, is ubiquitous in land plants. The mechanisms underlying circumnutation have been debated since Darwin's time. Experiments in space and mutant analyses have revealed that internal oscillatory (tropism-independent) movement and gravitropic response are involved in circumnutation. Female flower buds of tape grass (Vallisneria asiatica var. biwaensis) circumnutate on the water surface. Our observations and experiments with an artificial model indicated that gravitropism is barely involved in circumnutation. Instead, we show that helical intercalary growth at the base of peduncle plays the primary role in all movements in Vallisneria. This growth pattern produces torsional bud rotation, and gravity and buoyancy forces have a physical effect on the direction of peduncle elongation, resulting in bud circumnutation on the water surface. In contrast to other water-pollinated hydrophilous plants, circumnutation in Vallisneria enables female flowers to actively collect male flowers from a larger surface area of water. PMID:23355948

  18. Thermal surface signatures of ship propeller wakes in stratified waters

    NASA Astrophysics Data System (ADS)

    Voropayev, S. I.; Nath, C.; Fernando, H. J. S.

    2012-11-01

    When a ship moves in temperature stratified water, e.g., in the ocean diurnal thermocline, the propeller(s) as well as the turbulent boundary layer of the hull mix the surface water with underlying colder fluid. As a result, when observed from above, a temperature "wake signature" of ˜1-2 °C may be detected at the water surface. To quantify this phenomenon, theoretical modeling and physical experiments were conducted. The dominant processes responsible for thermal wake generation were identified and parameterized. Most important similarity parameters were derived and estimates for wake signature contrast were made. To verify model predictions, scaled experiments were conducted, with the water surface temperature measured using a sensitive infrared camera. Comparison of laboratory measurements with model estimates has shown satisfactory agreement, both qualitative and quantitatively. Estimates for ocean ship-wake scenarios are also given, which are supported by available field observations.

  19. Yersinia spp. in surface water in Matsue, Japan.

    PubMed

    Fukushima, H; Saito, K; Tsubokura, M; Otsuki, K

    1984-06-01

    Yersinia spp. (741 strains) were recovered from 81% of 48 surface water samples collected over a 12-month period from four rivers in Matsue, Japan. The precipitation methods with FeCl3 or Kaolin and the cold enrichment method with Peptone-Mannitol-Phosphate buffer solution were used for recovery. Isolates belonged to Yersinia enterocolitica (Ye) (133 strains), Yersinia intermedia (511 strains), Yersinia frederiksenii (57 strains), Yersinia kristensenii (10 strains) and X2-like organisms (30 strains). Thirty colonies of Ye O3 biotype 3 per ml surface water may relate to the drainage containing 2 X 10(4) Ye O3 biotype 3 per ml, from the piggery that raised Ye O3 biotype 3-positive pigs. There was the negative interrelation between the incidence of isolation of Yersinia spp. and the environmental- and water temperatures. This may be the first documentation of isolation of Ye O3 from surface water.

  20. The Proposed Surface Water and Ocean Topography (SWOT) Mission

    NASA Technical Reports Server (NTRS)

    Fu, Lee-Lueng; Alsdorf, Douglas; Rodriguez, Ernesto; Morrow, Rosemary; Mognard, Nelly; Vaze, Parag; Lafon, Thierry

    2012-01-01

    A new space mission concept called Surface Water and Ocean Topography (SWOT) is being developed jointly by a collaborative effort of the international oceanographic and hydrological communities for making high-resolution measurement of the water elevation of both the ocean and land surface water to answer the questions about the oceanic submesoscale processes and the storage and discharge of land surface water. The key instrument payload would be a Ka-band radar interferometer capable of making high-resolution wide-swath altimetry measurement. This paper describes the proposed science objectives and requirements as well as the measurement approach of SWOT, which is baselined to be launched in 2019. SWOT would demonstrate this new approach to advancing both oceanography and land hydrology and set a standard for future altimetry missions.

  1. Investigating the interface of superhydrophobic surfaces in contact with water.

    PubMed

    Doshi, Dhaval A; Shah, Pratik B; Singh, Seema; Branson, Eric D; Malanoski, Anthony P; Watkins, Erik B; Majewski, Jaroslaw; van Swol, Frank; Brinker, C Jeffrey

    2005-08-16

    Neutron reflectivity (NR) is used to probe the solid, liquid, vapor interface of a porous superhydrophobic (SH) surface submerged in water. A low-temperature, low-pressure technique was used to prepare a rough, highly porous organosilica aerogel-like film. UV/ozone treatments were used to control the surface coverage of hydrophobic organic ligands on the silica framework, allowing the contact angle with water to be continuously varied over the range of 160 degrees (superhydrophobic) to <10 degrees (hydrophilic). NR shows that the superhydrophobic nature of the surface prevents infiltration of water into the porous film. Atomic force microscopy and density functional theory simulations are used in combination to interpret the NR results and help establish the location, width, and nature of the SH film-water interface.

  2. Optical measuring technique for small scale water surface waves

    NASA Astrophysics Data System (ADS)

    Jahne, Bernd; Waas, Stefan

    1989-10-01

    This paper describes two optical measuring techniques for determining the spatial and temporal structure of small-scale surface waves: (1) the imaging slope gage (ISG) and (2) the reflective stereo slope gage (RSSG). The ISG is based on light refraction at the water surface; it records image sequences of the wave slope at a maximum area of 1 sq m. The RSSG technique involves illumination of the water surface from above by a monochromatic light source; its two CCD camera take stereo images of sequences of the specular reflexes returned by the water surface. Both instruments were successfully used in wind/wave facility investigations. The results show that they permit a much more detailed investigation of the physics of small scale waves than those made using conventional equipment, such as point measuring devices or laser slope gages.

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

    USGS Publications Warehouse

    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

  4. Concentration data for anthropogenic organic compounds in groundwater, surface water, and finished water of selected community water systems in the United States, 2002-10

    USGS Publications Warehouse

    Carter, Janet M.; Kingsbury, James A.; Hopple, Jessica A.; Delzer, Gregory C.

    2010-01-01

    The National Water-Quality Assessment Program of the U.S. Geological Survey began implementing Source Water-Quality Assessments (SWQAs) in 2001 that focus on characterizing the quality of source water and finished water of aquifers and major rivers used by some of the larger community water systems in the United States. As used in SWQA studies, source water is the raw (ambient) water collected at the supply well before water treatment (for groundwater) or the raw (ambient) water collected from the river near the intake (for surface water), and finished water is the water that has been treated and is ready to be delivered to consumers. Finished-water samples are collected before the water enters the distribution system. The primary objective of SWQAs is to determine the occurrence of more than 250 anthropogenic organic compounds in source water used by community water systems, many of which currently are unregulated in drinking water by the U.S. Environmental Protection Agency. A secondary objective is to understand recurrence patterns in source water and determine if these patterns also occur in finished water before distribution. SWQA studies were conducted in two phases for most studies completed by 2005, and in one phase for most studies completed since 2005. Analytical results are reported for a total of 295 different anthropogenic organic compounds monitored in source-water and finished-water samples collected during 2002-10. The 295 compounds were classified according to the following 13 primary use or source groups: (1) disinfection by-products; (2) fumigant-related compounds; (3) fungicides; (4) gasoline hydrocarbons, oxygenates, and oxygenate degradates; (5) herbicides and herbicide degradates; (6) insecticides and insecticide degradates; (7) manufacturing additives; (8) organic synthesis compounds; (9) pavement- and combustion-derived compounds; (10) personal-care and domestic-use products; (11) plant- or animal-derived biochemicals; (12) refrigerants and

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

    USGS Publications Warehouse

    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

  6. [Current status of surface water acidification in Northeast China].

    PubMed

    Xu, Guang-yi; Kang, Rong-hua; Luo, Yao; Duan, Lei

    2013-05-01

    In order to evaluate the status of surface water acidification in Northeast China, chemical composition of 33 small streams was investigated in August, 2011. It was found that only a few waters located in Changbai Mountain had pH of lower than 6.0, and all waters had acid neutralizing capacity (ANC) of higher than 0.2 meq x L(-1). This indicated that surface water acidification was not a regional environmental issue in Northeast China. HCO3- was the major anion, with SO4(2-) concentration mostly below 150 microeq x L(-1) and even much lower NO3- concentration. Low concentration of SO4(2-) and NO3- means no serious acid deposition in this area. However, the distribution of acidic forest soils, with low base cation weathering rate, could only provide limited buffering capacity for surface water to acidification in Northeast China, and the potential risk of water acidification still existed. Currently, acid deposition in Northeast Asia could hardly cause severe acidification of surface water. The neighboring countries should therefore not amplify the environmental impact by transboundary air pollutants from China.

  7. [Current status of surface water acidification in Northeast China].

    PubMed

    Xu, Guang-yi; Kang, Rong-hua; Luo, Yao; Duan, Lei

    2013-05-01

    In order to evaluate the status of surface water acidification in Northeast China, chemical composition of 33 small streams was investigated in August, 2011. It was found that only a few waters located in Changbai Mountain had pH of lower than 6.0, and all waters had acid neutralizing capacity (ANC) of higher than 0.2 meq x L(-1). This indicated that surface water acidification was not a regional environmental issue in Northeast China. HCO3- was the major anion, with SO4(2-) concentration mostly below 150 microeq x L(-1) and even much lower NO3- concentration. Low concentration of SO4(2-) and NO3- means no serious acid deposition in this area. However, the distribution of acidic forest soils, with low base cation weathering rate, could only provide limited buffering capacity for surface water to acidification in Northeast China, and the potential risk of water acidification still existed. Currently, acid deposition in Northeast Asia could hardly cause severe acidification of surface water. The neighboring countries should therefore not amplify the environmental impact by transboundary air pollutants from China. PMID:23914517

  8. Effects of drainage and water table control on groundwater and surface water quality

    SciTech Connect

    Chescheir, G.M.; Skaggs, R.W.; Gilliam, J.W.; Breve, M.A.; Munster, C.

    1995-12-31

    The objectives of the research project were to: conduct field experiments to measure and evaluate the effects of drainage, controlled drainage, and subirrigation of the following hydrologic and water quality variables: Movement and fate of fertilizer nutrients and sediment in surface runoff, shallow groundwater and subsurface drainage waters; and loss of pesticides in surface and subsurface drainage waters and their movement into shallow groundwaters; test the reliability of selected models for predicting the movement of pesticides and fertilizer nutrients to shallow groundwater and the losses of these pollutants via surface and subsurface drainage waters; and modify and further develop these existing models to improve their reliability.

  9. Percent recoveries of anthropogenic organic compounds with and without the addition of ascorbic acid to preserve finished-water samples containing free chlorine, 2004-10

    USGS Publications Warehouse

    Valder, Joshua F.; Delzer, Gregory C.; Bender, David A.; Price, Curtis V.

    2011-01-01

    This report presents finished-water matrix-spike recoveries of 270 anthropogenic organic compounds with and without the addition of ascorbic acid to preserve water samples containing free chlorine. Percent recoveries were calculated using analytical results from a study conducted during 2004-10 for the National Water-Quality Assessment (NAWQA) Program of the U.S. Geological Survey (USGS). The study was intended to characterize the effect of quenching on finished-water matrix-spike recoveries and to better understand the potential oxidation and transformation of 270 anthropogenic organic compounds. The anthropogenic organic compounds studied include those on analytical schedules 1433, 2003, 2033, 2060, 2020, and 4024 of the USGS National Water Quality Laboratory. Three types of samples were collected from 34 NAWQA locations across the Nation: (1) quenched finished-water samples (not spiked), (2) quenched finished-water matrix-spike samples, and (3) nonquenched finished-water matrix-spike samples. Percent recoveries of anthropogenic organic compounds in quenched and nonquenched finished-water matrix-spike samples are presented. Comparisons of percent recoveries between quenched and nonquenched spiked samples can be used to show how quenching affects finished-water samples. A maximum of 18 surface-water and 34 groundwater quenched finished-water matrix-spike samples paired with nonquenched finished-water matrix-spike samples were analyzed. Percent recoveries for the study are presented in two ways: (1) finished-water matrix-spike samples supplied by surface-water or groundwater, and (2) by use (or source) group category for surface-water and groundwater supplies. Graphical representations of percent recoveries for the quenched and nonquenched finished-water matrix-spike samples also are presented.

  10. Nano-porous pottery using calcined waste sediment from tap water production as an additive.

    PubMed

    Sangsuk, Supin; Khunthon, Srichalai; Nilpairach, Siriphan

    2010-10-01

    A suspension of sediment from a lagoon in a tap water production plant was collected for this experiment. The suspension was spray dried and calcined at 700 °C for 1 h. After calcining, 30 wt.% of the sediment were mixed with pottery clay. Samples with and without calcined sediment were sintered at 900, 1000 and 1100 °C. The results show that calcined sediment can be used as an additive in pottery clay. The samples with calcined sediment show higher porosity, water absorption and flexural strength, especially for 900 and 1000 °C. At 900 °C, samples with calcined sediment show a porosity of 50% with an average pore size of 68 nm, water absorption of 31% and flexural strength of 12.61 MPa.

  11. Structure and stability of pyrophyllite edge surfaces: Effect of temperature and water chemical potential

    NASA Astrophysics Data System (ADS)

    Kwon, Kideok D.; Newton, Aric G.

    2016-10-01

    regardless of the water chemical potential. The equilibrium morphology of pyrophyllite crystals is also expected to be dependent on these two environmental variables. Surface defects may impact the surface reactivity. We discuss the thermodynamic stability of a possible Si cation vacancy defect which provides additional hydroxyl group on the surface.

  12. Experimental Values of the Surface Tension of Supercooled Water

    NASA Technical Reports Server (NTRS)

    Hacker, P. T.

    1951-01-01

    The results of surface-tension measurements for supercooled water are presented. A total of 702 individual measurements of surface tension of triple-distilled water were made in the temperature range, 27 to -22.2 C, with 404 of these measurements at temperatures below 0 C. The increase in magnitude of surface tension with decreasing temperature, as indicated by measurements above 0 C, continues to -22.2 C. The inflection point in the surface-tension - temperature relation in the vicinity of 0 C, as indicated by the International Critical Table values for temperatures down to -8 C, is substantiated by the measurements in the temperature range, 0 to -22.2 C. The surface tension increases at approximately a linear rate from a value of 76.96+/-0.06 dynes per centimeter at -8 C to 79.67+/-0.06 dynes per centimeter at -22.2 C.

  13. Influence of surface structure and chemistry on water droplet splashing.

    PubMed

    Koch, Kerstin; Grichnik, Roland

    2016-08-01

    Water droplet splashing and aerosolization play a role in human hygiene and health systems as well as in crop culturing. Prevention or reduction of splashing can prevent transmission of diseases between animals and plants and keep technical systems such as pipe or bottling systems free of contamination. This study demonstrates to what extent the surface chemistry and structures influence the water droplet splashing behaviour. Smooth surfaces and structured replicas of Calathea zebrina (Sims) Lindl. leaves were produced. Modification of their wettability was done by coating with hydrophobizing and hydrophilizing agents. Their wetting was characterized by contact angle measurement and splashing behaviour was observed with a high-speed video camera. Hydrophobic and superhydrophilic surfaces generally showed fewer tendencies to splash than hydrophobic ones. Structuring amplified the underlying behaviour of the surface chemistries, increasing hydrophobic surfaces' tendency to splash and decreasing splash on hydrophilic surfaces by quickly transporting water off the impact point by capillary forces. The non-porous surface structures found in C. zebrina could easily be applied to technical products such as plastic foils or mats and coated with hydrophilizing agents to suppress splash in areas of increased hygiene requirements or wherever pooling of liquids is not desirable.This article is part of the themed issue 'Bioinspired hierarchically structured surfaces for green science'. PMID:27354737

  14. Influence of surface structure and chemistry on water droplet splashing.

    PubMed

    Koch, Kerstin; Grichnik, Roland

    2016-08-01

    Water droplet splashing and aerosolization play a role in human hygiene and health systems as well as in crop culturing. Prevention or reduction of splashing can prevent transmission of diseases between animals and plants and keep technical systems such as pipe or bottling systems free of contamination. This study demonstrates to what extent the surface chemistry and structures influence the water droplet splashing behaviour. Smooth surfaces and structured replicas of Calathea zebrina (Sims) Lindl. leaves were produced. Modification of their wettability was done by coating with hydrophobizing and hydrophilizing agents. Their wetting was characterized by contact angle measurement and splashing behaviour was observed with a high-speed video camera. Hydrophobic and superhydrophilic surfaces generally showed fewer tendencies to splash than hydrophobic ones. Structuring amplified the underlying behaviour of the surface chemistries, increasing hydrophobic surfaces' tendency to splash and decreasing splash on hydrophilic surfaces by quickly transporting water off the impact point by capillary forces. The non-porous surface structures found in C. zebrina could easily be applied to technical products such as plastic foils or mats and coated with hydrophilizing agents to suppress splash in areas of increased hygiene requirements or wherever pooling of liquids is not desirable.This article is part of the themed issue 'Bioinspired hierarchically structured surfaces for green science'.

  15. High Conductivity Water Treatment Using Water Surface Discharge with Nonmetallic Electrodes

    NASA Astrophysics Data System (ADS)

    Wang, Xiaoping; Zhang, Xingwang; Lei, Lecheng

    2013-06-01

    Although electrohydraulic discharge is effective for wastewater treatment, its application is restricted by water conductivity and limited to the treatment of low conductivity water. For high conductivity water treatment, water-surface discharge is the preferred choice. However, the metallic electrodes are easily corroded because of the high temperature and strong oxidative environment caused by gas phase discharge and the electrochemical reaction in water. As a result, the efficiency of the water treatment might be affected and the service life of the reactor might be shortened. In order to avoid the corrosion problem, nonmetallic electrode water-surface discharge is introduced into high conductivity water treatment in the present study. Carbon-felt and water were used as the high voltage electrode and ground electrode, respectively. A comparison of the electrical and chemical characteristics showed that nonmetallic electrode discharge maintained the discharge characteristics and enhanced the energy efficiency, and furthermore, the corrosion of metal electrodes was avoided.

  16. Groundwater interactions with surface waters: consequences on diffuse pollution pathways

    NASA Astrophysics Data System (ADS)

    Azzellino, Arianna; Salvetti, Roberta; Gorla, Elena; Parati, Paolo; Malagò, Anna; Ragusa, Francesca; Vismara, Renato

    2010-05-01

    The interactions between groundwater and surface water are complex. Surface-waters and groundwaters are, in fact, linked components of a hydrologic continuum. In general, diffuse pollution in surface waters is difficult to quantify since it follows a multitude of pathways and acts on different time scales. During rainfall events most of the diffuse pollutant load follows the surface runoff pathways and, reaches the surface acquifers however, a fraction of this load will follows the sub-surface runoff pathways and it will possibly reach the surface acquifers after a certain time lag. The time scale of the sub-surface runoff pathways is very different from the surface runoff time scale and rarely a subsurface diffuse pollution event can be directly correlated to a specific rainfall event. This is the reason why even though there are models that enable to simulate the groundwater-surface water system (GW-SW), yet the effect of these interactions in terms of diffuse pollution pathways and their correspondent effect on the quality of surface waters to date are largely unknown. To upgrade the conceptual modeling of the "groundwater-surface water" system, a broader perspective of such interactions across and between surfacewater bodies is needed. Multidimensional analyses may help in understanding the effect of such interactions, as the characterization of the hydraulic interface and its spatial variability. To fully understand these interactions, modeling studies need to be coupled to sound and robust monitoring of surface- and ground- water quality data. Modeling can be combined with multivariate statistical techniques (e.g. factor analysis) to improve our capability to "detect" the effect of the sub-surface runoff on the water quality of specific water courses. Aim of this study was to analyse the groundwater contribution to the total nutrient river load of different watersheds that share a very intensive agriculture and landfarming system. The studied watersheds all

  17. Organic Matter and Water Addition Enhance Soil Respiration in an Arid Region

    PubMed Central

    Lai, Liming; Wang, Jianjian; Tian, Yuan; Zhao, Xuechun; Jiang, Lianhe; Chen, Xi; Gao, Yong; Wang, Shaoming; Zheng, Yuanrun

    2013-01-01

    Climate change is generally predicted to increase net primary production, which could lead to additional C input to soil. In arid central Asia, precipitation has increased and is predicted to increase further. To assess the combined effects of these changes on soil CO2 efflux in arid land, a two factorial manipulation experiment in the shrubland of an arid region in northwest China was conducted. The experiment used a nested design with fresh organic matter and water as the two controlled parameters. It was found that both fresh organic matter and water enhanced soil respiration, and there was a synergistic effect of these two treatments on soil respiration increase. Water addition not only enhanced soil C emission, but also regulated soil C sequestration by fresh organic matter addition. The results indicated that the soil CO2 flux of the shrubland is likely to increase with climate change, and precipitation played a dominant role in regulating soil C balance in the shrubland of an arid region. PMID:24204907

  18. Surface tension isotherms of the dioxane-acetone-water and glycerol-ethanol-water ternary systems

    NASA Astrophysics Data System (ADS)

    Dzhambulatov, R. S.; Dadashev, R. Kh.; Elimkhanov, D. Z.; Dadashev, I. N.

    2016-10-01

    The results of the experimental and theoretical studies of the concentration dependence of surface tension of aqueous solutions of the 1,4-dioxane-acetone-water and glycerol-ethanol-water ternary systems were given. The studies were performed by the hanging-drop method on a DSA100 tensiometer. The maximum error of surface tension was 1%. The theoretical models for calculating the surface tension of the ternary systems of organic solutions were analyzed.

  19. Nitrification in lake sediment with addition of drinking water treatment residuals.

    PubMed

    Wang, Changhui; Liu, Juanfeng; Wang, Zhixin; Pei, Yuansheng

    2014-06-01

    Drinking water treatment residuals (WTRs), non-hazardous by-products generated during potable water production, can effectively reduce the lake internal phosphorus (P) loading and improve water quality in lakes. It stands to reason that special attention regarding the beneficial reuse of WTRs should be given not only to the effectiveness of P pollution control, but also to the effects on the migration and transformation of other nutrients (e.g., nitrogen (N)). In this work, based on laboratory enrichment tests, the effects of WTRs addition on nitrification in lake sediment were investigated using batch tests, fluorescence in situ hybridization, quantitative polymerase chain reaction and phylogenetic analysis techniques. The results indicated that WTRs addition had minor effects on the morphologies of AOB and NOB; however, the addition slightly enhanced the sediment nitrification potential from 12.8 to 13.2 μg-N g(-1)-dry sample h(-1) and also increased the ammonia oxidation bacteria (AOB) and nitrite oxidizing bacteria (NOB) abundances, particularly the AOB abundances (P < 0.05), which increased from 1.11 × 10(8) to 1.31 × 10(8) copies g(-1)-dry sample. Moreover, WTRs addition was beneficial to the enrichment of Nitrosomonas and Nitrosospira multiformis and promoted the emergence of a new Nitrospira cluster, causing the increase in AOB and NOB diversities. Further analysis showed that the variations of nitrification in lake sediment after WTRs addition were primarily due to the decrease of bioavailable P, the introduction of new nitrifiers and the increase of favorable carriers for microorganism attachment in sediments. Overall, these results suggested that WTRs reuse for the control of lake internal P loading would also lead to conditions that are beneficial to nitrification.

  20. Ground Water and Surface Water in the Haiku Area, East Maui, Hawaii

    USGS Publications Warehouse

    Gingerich, Stephen B.

    1999-01-01

    The Haiku study area lies on the gently sloping eastern flank of the East Maui Volcano (Haleakala) between the drainage basins of Maliko Gulch to the west and Kakipi Gulch to the east. The study area lies on the northwest rift zone of East Maui Volcano, a geologic feature 3 to 5 miles wide marked by surface expressions such as cinder, spatter, and pumice cones. The study area contains two geologic units, the main shield-building stage Honomanu Basalt and the Kula Volcanics. The hydraulic conductivity of the Honomanu Basalt was estimated to be between 1,000 and 3,600 feet per day on the basis of aquifer tests and 3,300 feet per day on the basis of the regional recharge rate and observed ground-water heads. The hydraulic conductivity of the Kula Volcanics is expected to be several orders of magnitude lower. An estimated 191 million gallons per day of rainfall and 22 million gallons per day of fog drip reach the study area and about 98 million gallons per day enters the ground-water system as recharge. Nearly all of the ground water currently withdrawn in the study area is from well 5520-01 in Maliko Gulch, where historic withdrawal rates have averaged about 2.8 million gallons per day. An additional 18 million gallons per day of ground-water withdrawal is proposed. Flow in Waiohiwi Gulch, a tributary to Maliko Gulch, is perennial between about 2,000 ft and 4,000 ft altitude. At lower altitudes in Maliko Gulch, flow is perennial at only a few spots downstream of springs and near the coast. The Kuiaha and Kaupakulua Gulch systems are usually dry from sea level to an altitude of 350 feet and gain water from about 350 feet to about 900 feet altitude. The two main branches of the Kaupakulua Gulch system alternately gain and lose water as high as 2,400 feet altitude. Kakipi Gulch has perennial flow over much of its length but is often dry near the coast below 400 feet altitude. Fresh ground water occurs in two main forms: (1) as perched high-level water held up by

  1. Effect of Grain Size on Uranium(VI) Surface Complexation Kinetics and Adsorption Additivity

    SciTech Connect

    Shang, Jianying; Liu, Chongxuan; Wang, Zheming; Zachara, John M.

    2011-07-27

    Laboratory experiments were performed to investigate the contribution of variable grain sizes to uranium adsorption/desorption in a sediment collected from the US DOE Hanford site. The sediment was wet-sieved into four size fractions: coarse sand (1-2 mm), medium sand (0.2-1 mm), fine sand (0.05-0.2 mm), and clay/silt fraction (< 0.05mm). For each size fraction and their composite (sediment), batch experiments were performed to determine uranium adsorption isotherms, and stirred flow-cell experiments were conducted to derive kinetic data of uranium adsorption and subsequent desorption. The results showed that uranium adsorption isotherms and adsorption/desorption kinetics were size-specific, reflecting the effects of size-specific adsorption site concentration and kinetic rate constants. The larger-size fraction had a larger mass percentage in the sediment, but with a smaller adsorption site concentration and generally a slower uranium adsorption/desorption rate. The same equilibrium surface complexation reaction and reaction constant could describe uranium adsorption isotherms for all size fractions and the composite after accounting for the effect of adsorption site concentration. Mass-weighted, linear additivity was observed for both uranium adsorption isotherms and adsorption/desorption kinetics in the composite. Our analysis also showed that uranium adsorption site concentration estimated from the adsorption isotherms was 3 orders of magnitude less than a site concentration estimated from sediment surface area and generic site density. One important implication of this study is that grain size distribution may be used to estimate uranium adsorption site, and adsorption/desorption kinetic rates in heterogeneous sediments from a common location.

  2. Surface water data at Los Alamos National Laboratory: 1996 water year. Progress report

    SciTech Connect

    Shaull, D.A.; Alexander, M.R.; Reynolds, R.P.; McLean, C.T.

    1996-11-01

    The principle investigators collected and computed surface water discharge data from 17 stream-gaging stations that cover most of Los Alamos National Laboratory. The data show less runoff than do data for the 1995 water year. Water chemistry data from larger storm events occurring at some stations are also published here.

  3. Hydrochemical characteristics and water quality assessment of surface water and groundwater in Songnen plain, Northeast China.

    PubMed

    Zhang, Bing; Song, Xianfang; Zhang, Yinghua; Han, Dongmei; Tang, Changyuan; Yu, Yilei; Ma, Ying

    2012-05-15

    Water quality is the critical factor that influence on human health and quantity and quality of grain production in semi-humid and semi-arid area. Songnen plain is one of the grain bases in China, as well as one of the three major distribution regions of soda saline-alkali soil in the world. To assess the water quality, surface water and groundwater were sampled and analyzed by fuzzy membership analysis and multivariate statistics. The surface water were gather into class I, IV and V, while groundwater were grouped as class I, II, III and V by fuzzy membership analysis. The water samples were grouped into four categories according to irrigation water quality assessment diagrams of USDA. Most water samples distributed in category C1-S1, C2-S2 and C3-S3. Three groups were generated from hierarchical cluster analysis. Four principal components were extracted from principal component analysis. The indicators to water quality assessment were Na, HCO(3), NO(3), Fe, Mn and EC from principal component analysis. We conclude that surface water and shallow groundwater are suitable for irrigation, the reservoir and deep groundwater in upstream are the resources for drinking. The water for drinking should remove of the naturally occurring ions of Fe and Mn. The control of sodium and salinity hazard is required for irrigation. The integrated management of surface water and groundwater for drinking and irrigation is to solve the water issues.

  4. 77 FR 12227 - Long Term 2 Enhanced Surface Water Treatment Rule: Uncovered Finished Water Reservoirs; Public...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-29

    ... contaminants in uncovered finished water reservoirs; and potential assessment approaches to determine the... AGENCY 40 CFR Parts 141 and 142 Long Term 2 Enhanced Surface Water Treatment Rule: Uncovered Finished Water Reservoirs; Public Meeting AGENCY: Environmental Protection Agency (EPA). ACTION: Notice of...

  5. DETECTION OF A GROUND-WATER/SURFACE-WATER INTERFACE WITH DIRECT-PUSH EQUIPMENT

    EPA Science Inventory

    A ground-water/surface-water interface (GSI) was documented at the Thermo Chem CERCLA Site in Muskegon, MI via direct-push (DP) sampling. At that time, contaminated ground water flowed from the upland area of the site into the Black Creek floodplain. DP rods equipped with a 1.5...

  6. SURFACE WATER AND GROUND WATER QUALITY MONITORING FOR RESTORATION OF URBAN LAKES IN GREATER HYDERABAD, INDIA

    NASA Astrophysics Data System (ADS)

    Mohanty, A. K.

    2009-12-01

    SURFACE WATER AND GROUND WATER QUALITY MONITORING FOR RESTORATION OF URBAN LAKES IN GREATER HYDERABAD, INDIA A.K. Mohanty, K. Mahesh Kumar, B. A. Prakash and V.V.S. Gurunadha Rao Ecology and Environment Group National Geophysical Research Institute, (CSIR) Hyderabad - 500 606, India E-mail:atulyakumarmohanty@yahoo.com Abstract: Hyderabad Metropolitan Development Authority has taken up restoration of urban lakes around Hyderabad city under Green Hyderabad Environment Program. Restoration of Mir Alam Tank, Durgamcheruvu, Patel cheruvu, Pedda Cheruvu and Nallacheruvu lakes have been taken up under the second phase. There are of six lakes viz., RKPuramcheruvu, Nadimicheruvu (Safilguda), Bandacheruvu Patelcheruvu, Peddacheruvu, Nallacheruvu, in North East Musi Basin covering 38 sq km. Bimonthly monitoring of lake water quality for BOD, COD, Total Nitrogen, Total phosphorous has been carried out for two hydrological cycles during October 2002- October 2004 in all the five lakes at inlet channels and outlets. The sediments in the lake have been also assessed for nutrient status. The nutrient parameters have been used to assess eutrophic condition through computation of Trophic Status Index, which has indicated that all the above lakes under study are under hyper-eutrophic condition. The hydrogeological, geophysical, water quality and groundwater data base collected in two watersheds covering 4 lakes has been used to construct groundwater flow and mass transport models. The interaction of lake-water with groundwater has been computed for assessing the lake water budget combining with inflow and outflow measurements on streams entering and leaving the lakes. Individual lake water budget has been used for design of appropriate capacity of Sewage Treatment Plants (STPs) on the inlet channels of the lakes for maintaining Full Tank Level (FTL) in each lake. STPs are designed for tertiary treatment i.e. removal of nutrient load viz., Phosphates and Nitrates. Phosphates are

  7. Model for outgassing of water from metal surfaces

    SciTech Connect

    Li, Minxu; Dylla, Fred

    1993-06-01

    Numerous measurements of outgassing from metal surfaces show that the outgassing obeys a power law of the form Q=Q{sub 10}t{sup -alpha}, where alpha is typically near unity. For unbaked systems, outgassing is dominated by water. This work demonstrates that alpha is a function of the water vapor exposure during venting of the system, and the physical properties of the passivation oxide layer on the surface. An analytic expression for the outgassing rate is derived based on the assumption that the rate of water diffusing through the passivation oxide layer to the surface governs the rate of its release into the vacuum. The source distribution function for the desorbing water is assumed to be a combination of a Gaussian distribution centered at the interior surface driven by atmospheric exposure, and a uniform concentration throughout the bulk. We have measured the outgassing rate from a clean stainless-steel (type 304) chamber as a function of water exposure to the chamber surface from <1 to 600 monolayers. The measured outgassing rate data show that alpha tends to 0.5 for low H{sub 2}O exposures and tends to 1.5 for high H{sub 2}O exposures as predicted by the model.

  8. Additive pressures of elevated sea surface temperatures and herbicides on symbiont-bearing foraminifera.

    PubMed

    van Dam, Joost W; Negri, Andrew P; Mueller, Jochen F; Altenburger, Rolf; Uthicke, Sven

    2012-01-01

    Elevated ocean temperatures and agrochemical pollution individually threaten inshore coral reefs, but these pressures are likely to occur simultaneously. Experiments were conducted to evaluate the combined effects of elevated temperature and the photosystem II (PSII) inhibiting herbicide diuron on several types of symbiotic algae (diatom, dinoflagellate or rhodophyte) of benthic foraminifera in hospite. Diuron was shown to evoke a direct effect on photosynthetic efficiency (reduced effective PSII quantum yield ΔF/F'(m)), while elevated temperatures (>30 °C, only 2 °C above current average summer temperatures) were observed to impact photosynthesis more indirectly by causing reductions in maximum PSII quantum yield (F(v)/F(m)), interpreted as photodamage. Additionally, elevated temperatures were shown to cause bleaching through loss of chlorophyll a in foraminifera hosting either diatoms or dinoflagellates. A significant linear correlation was found between reduced F(v)/F(m) and loss of chlorophyll a. In most cases, symbionts within foraminifera proved more sensitive to thermal stress in the presence of diuron (≥ 1 µg L(-1)). The mixture toxicity model of Independent Action (IA) described the combined effects of temperature and diuron on the photosystem of species hosting diatoms or dinoflagellates convincingly and in agreement with probabilistic statistics, so a response additive joint action can be assumed. We thus demonstrate that improving water quality can improve resilience of symbiotic phototrophs to projected increases in ocean temperatures. As IA described the observed combined effects from elevated temperature and diuron stress it may therefore be employed for prediction of untested mixtures and for assessing the efficacy of management measures. PMID:22439012

  9. Additive Pressures of Elevated Sea Surface Temperatures and Herbicides on Symbiont-Bearing Foraminifera

    PubMed Central

    van Dam, Joost W.; Negri, Andrew P.; Mueller, Jochen F.; Altenburger, Rolf; Uthicke, Sven

    2012-01-01

    Elevated ocean temperatures and agrochemical pollution individually threaten inshore coral reefs, but these pressures are likely to occur simultaneously. Experiments were conducted to evaluate the combined effects of elevated temperature and the photosystem II (PSII) inhibiting herbicide diuron on several types of symbiotic algae (diatom, dinoflagellate or rhodophyte) of benthic foraminifera in hospite. Diuron was shown to evoke a direct effect on photosynthetic efficiency (reduced effective PSII quantum yield ΔF/F′m), while elevated temperatures (>30°C, only 2°C above current average summer temperatures) were observed to impact photosynthesis more indirectly by causing reductions in maximum PSII quantum yield (Fv/Fm), interpreted as photodamage. Additionally, elevated temperatures were shown to cause bleaching through loss of chlorophyll a in foraminifera hosting either diatoms or dinoflagellates. A significant linear correlation was found between reduced Fv/Fm and loss of chlorophyll a. In most cases, symbionts within foraminifera proved more sensitive to thermal stress in the presence of diuron (≥1 µg L−1). The mixture toxicity model of Independent Action (IA) described the combined effects of temperature and diuron on the photosystem of species hosting diatoms or dinoflagellates convincingly and in agreement with probabilistic statistics, so a response additive joint action can be assumed. We thus demonstrate that improving water quality can improve resilience of symbiotic phototrophs to projected increases in ocean temperatures. As IA described the observed combined effects from elevated temperature and diuron stress it may therefore be employed for prediction of untested mixtures and for assessing the efficacy of management measures. PMID:22439012

  10. Additive pressures of elevated sea surface temperatures and herbicides on symbiont-bearing foraminifera.

    PubMed

    van Dam, Joost W; Negri, Andrew P; Mueller, Jochen F; Altenburger, Rolf; Uthicke, Sven

    2012-01-01

    Elevated ocean temperatures and agrochemical pollution individually threaten inshore coral reefs, but these pressures are likely to occur simultaneously. Experiments were conducted to evaluate the combined effects of elevated temperature and the photosystem II (PSII) inhibiting herbicide diuron on several types of symbiotic algae (diatom, dinoflagellate or rhodophyte) of benthic foraminifera in hospite. Diuron was shown to evoke a direct effect on photosynthetic efficiency (reduced effective PSII quantum yield ΔF/F'(m)), while elevated temperatures (>30 °C, only 2 °C above current average summer temperatures) were observed to impact photosynthesis more indirectly by causing reductions in maximum PSII quantum yield (F(v)/F(m)), interpreted as photodamage. Additionally, elevated temperatures were shown to cause bleaching through loss of chlorophyll a in foraminifera hosting either diatoms or dinoflagellates. A significant linear correlation was found between reduced F(v)/F(m) and loss of chlorophyll a. In most cases, symbionts within foraminifera proved more sensitive to thermal stress in the presence of diuron (≥ 1 µg L(-1)). The mixture toxicity model of Independent Action (IA) described the combined effects of temperature and diuron on the photosystem of species hosting diatoms or dinoflagellates convincingly and in agreement with probabilistic statistics, so a response additive joint action can be assumed. We thus demonstrate that improving water quality can improve resilience of symbiotic phototrophs to projected increases in ocean temperatures. As IA described the observed combined effects from elevated temperature and diuron stress it may therefore be employed for prediction of untested mixtures and for assessing the efficacy of management measures.

  11. Additive Effects on Si3n4 Oxidation/Volatilization in Water Vapor

    NASA Technical Reports Server (NTRS)

    Opila, Elizabeth J.; Robinson, R. Craig; Fox, Dennis S.; Wenglarz, Richard A.; Ferber, Mattison K.

    2002-01-01

    Two commercially available additive-containing silicon nitride materials were exposed in four environments which range in severity from dry oxygen at 1 atm pressure, and low gas velocity to an actual turbine engine. Oxidation and volatilization kinetics were monitored at temperatures ranging from 1066 to 1400 C. The main purpose of this paper is to examine the surface oxide morphology resulting from the exposures. It was found that the material surface was enriched in rare earth silicate phases in combustion environments when compared to the oxides formed on materials exposed in dry oxygen. However, the in situ formation of rare earth disilicate phases offered little additional protection from the volatilization of silica observed in combustion environments. It was concluded that externally applied environmental barrier coatings are needed to protect additive-containing silicon nitride materials from volatilization reactions in combustion environments. Introduction Si3N4 is proposed for use as components, such as vanes, in turbine applications. Tens of thousands of hours of life are needed for both land-based turbines and aeropropulsion applications. Additive-containing SisN4 materials are

  12. Study on Nucleation of Water on Solid Surface

    NASA Astrophysics Data System (ADS)

    Okawa, Seiji; Saito, Akio; Matsui, Tatsuyuki

    Heterogeneous nucleation of water was investigated using Molecular Dynamics method. Solid with fcc(111) surface was placed at the bottom of a cell consisting of 864 water molecules. ST2 model with NPT ensemble was used. The pressure and temperature were set at 0.1MPa and 275K, respectively. The interaction between water and the solid was based on the equations proposed by Spohr. Exception was made on the lattice constant which was slightly modified to fit with that for ice structure. The shape of the solid surface was considered. It was found that the only one layer of water molecules was adsorbed in a case of a flat surface, whereas ice nucleation occurred by removing some of the atoms from the surface. Spohr's interaction was also modified so that the dipole moment of water became anti-ferroelectric. It was found that the modification increased the ice growth, further. The effect of lattice constant of solid on nucleation was also investigated. It was found that the variation on lattice constant with a few percent from that of ice was acceptable for nucleation, especially on shrinking side. On expanding side, however, it gave some gaps for water molecules to fit in other than that for ice structure, and it prevented the growth of ice.

  13. Molecular dynamics study of oil detachment from an amorphous silica surface in water medium

    NASA Astrophysics Data System (ADS)

    Chen, Jiaxuan; Si, Hao; Chen, Wenyang

    2015-10-01

    In this paper, the mechanism of oil detachment from optical glass in water medium is studied by using molecular dynamics simulation. At the beginning, some undecane molecules are adsorbed on the amorphous silica surface to get contaminated glass. Upon addition of 6000 water molecules, most of the undecane molecules on the substrate surface can be detached from an amorphous silica surface through three stages. The formation of different directions of water channels is vital for oil detachment. The electrostatic interaction of water substrate contributes to disturbing the aggregates of undecane molecules and the H-bonding interaction between the water molecules is helpful for the oil puddle away from the substrate. However, there is still some oil molecules residue on the substrate surface after water cleaning. The simulation results showed that the specific ring potential well of amorphous silica surface will hinder the detachment of oil molecules. We also find that the formation of the specific ring potential well is related to the number of atoms and the average radius in silica atomic rings. Increasing the upward lift force, which acts on the hydrocarbon tail of oil molecules, will be benefit to clear the oil pollution residues from the glass surface.

  14. Elucidating the mechanism of water adsorption on aluminum surface by SIMS

    NASA Astrophysics Data System (ADS)

    Chen, J. R.; Hsu, H. T.; Lee, J. Y.; Shen, T. H.; Hsiung, G. Y.; Chang, S. L.

    2004-07-01

    This study investigated the adsorption of water on aluminum surface. Aluminum samples exposed to different amounts of water vapor, with or without nitrogen gas mixture, were analyzed by a secondary ion mass spectrometer (SIMS). A two stage load-lock system was used to reduce the water vapor contamination attributed from the transfer of the samples. Experimental results indicate that the background water signal on the sample is linearly proportional to the amount of exposure. However, the intensity of background water signal on the sample displayed a power of 3.8 of the maximum transient pressure in the main chamber during sample transfer. Additionally, the effect of adiabatic expansion on water adsorption was studied by comparing different exposure conditions with respect to the intensity of water signal. According to those results, more water was adsorbed on aluminum surface when the exposure water mixed with nitrogen gas of ˜1 atm. This finding implies that adiabatic expansion may be a mechanism of water adsorbed on sample surface during evacuation.

  15. Vulnerability of drinking-water wells in La Crosse, Wisconsin, to enteric-virus contamination from surface water contributions

    USGS Publications Warehouse

    Borchardt, M. A.; Haas, N.L.; Hunt, R.J.

    2004-01-01

    Human enteric viruses can contaminate municipal drinking-water wells, but few studies have examined the routes by which viruses enter these wells. In the present study, the objective was to monitor the municipal wells of La Crosse, Wisconsin, for enteric viruses and determine whether the amount of Mississippi River water infiltrating the wells was related to the frequency of virus detection. From March 2001 to February 2002, one river water site and four wells predicted by hydrogeological modeling to have variable degrees of surface water contributions were sampled monthly for enteric viruses, microbial indicators of sanitary quality, and oxygen and hydrogen isotopes. 18O/ 16O and 2H/1H ratios were used to determine the level of surface water contributions. All samples were collected prior to chlorination at the wellhead. By reverse transcription-PCR (RT-PCR), 24 of 48 municipal well water samples (50%) were positive for enteric viruses, including enteroviruses, rotavirus, hepatitis A virus (HAV), and noroviruses. Of 12 river water samples, 10 (83%) were virus positive by RT-PCR. Viable enteroviruses were not detected by cell culture in the well samples, although three well samples were positive for culturable HAV. Enteroviruses detected in the wells by RT-PCR were identified as several serotypes of echoviruses and group A and group B coxsackieviruses. None of the well water samples was positive for indicators of sanitary quality, namely male-specific and somatic coliphages, total coliform bacteria, Escherichia coli, and fecal enterococci. Contrary to expectations, viruses were found in all wells regardless of the level of surface water contributions. This result suggests that there were other unidentified sources, in addition to surface water, responsible for the contamination.

  16. Vulnerability of Drinking-Water Wells in La Crosse, Wisconsin, to Enteric-Virus Contamination from Surface Water Contributions

    PubMed Central

    Borchardt, Mark A.; Haas, Nathaniel L.; Hunt, Randall J.

    2004-01-01

    Human enteric viruses can contaminate municipal drinking-water wells, but few studies have examined the routes by which viruses enter these wells. In the present study, the objective was to monitor the municipal wells of La Crosse, Wisconsin, for enteric viruses and determine whether the amount of Mississippi River water infiltrating the wells was related to the frequency of virus detection. From March 2001 to February 2002, one river water site and four wells predicted by hydrogeological modeling to have variable degrees of surface water contributions were sampled monthly for enteric viruses, microbial indicators of sanitary quality, and oxygen and hydrogen isotopes. 18O/16O and 2H/1H ratios were used to determine the level of surface water contributions. All samples were collected prior to chlorination at the wellhead. By reverse transcription-PCR (RT-PCR), 24 of 48 municipal well water samples (50%) were positive for enteric viruses, including enteroviruses, rotavirus, hepatitis A virus (HAV), and noroviruses. Of 12 river water samples, 10 (83%) were virus positive by RT-PCR. Viable enteroviruses were not detected by cell culture in the well samples, although three well samples were positive for culturable HAV. Enteroviruses detected in the wells by RT-PCR were identified as several serotypes of echoviruses and group A and group B coxsackieviruses. None of the well water samples was positive for indicators of sanitary quality, namely male-specific and somatic coliphages, total coliform bacteria, Escherichia coli, and fecal enterococci. Contrary to expectations, viruses were found in all wells regardless of the level of surface water contributions. This result suggests that there were other unidentified sources, in addition to surface water, responsible for the contamination. PMID:15466536

  17. Numerical study of the effect of water addition on gas explosion.

    PubMed

    Liang, Yuntao; Zeng, Wen

    2010-02-15

    Through amending the SENKIN code of CHEMKIN III chemical kinetics package, a computational model of gas explosion in a constant volume bomb was built, and the detailed reaction mechanism (GRI-Mech 3.0) was adopted. The mole fraction profiles of reactants, some selected free radicals and catastrophic gases in the process of gas explosion were analyzed by this model. Furthermore, through the sensitivity analysis of the reaction mechanism of gas explosion, the dominant reactions that affect gas explosion and the formation of catastrophic gases were found out. At the same time, the inhibition mechanisms of water on gas explosion and the formation of catastrophic gases were analyzed. The results show that the induced explosion time is prolonged, and the mole fractions of reactant species such as CH(4), O(2) and catastrophic gases such as CO, CO(2) and NO are decreased as water is added to the mixed gas. With the water fraction in the mixed gas increasing, the sensitivities of the dominant reactions contributing to CH(4), CO(2) are decreased and the sensitivity coefficients of CH(4), CO and NO mole fractions are also decreased. The inhibition of gas explosion with water addition can be ascribed to the significant decrease of H, O and OH in the process of gas explosion due to the water presence. PMID:19811873

  18. Suppression of methane/air explosion by ultrafine water mist containing sodium chloride additive.

    PubMed

    Cao, Xingyan; Ren, Jingjie; Zhou, Yihui; Wang, Qiuju; Gao, Xuliang; Bi, Mingshu

    2015-03-21

    The suppression effect of ultrafine mists on methane/air explosions with methane concentrations of 6.5%, 8%, 9.5%, 11%, and 13.5% were experimentally studied in a closed visual vessel. Ultrafine water/NaCl solution mist as well as pure water mist was adopted and the droplet sizes of mists were measured by phase doppler particle analyzer (PDPA). A high speed camera was used to record the flame evolution processes. In contrast to pure water mist, the flame propagation speed, the maximum explosion overpressure (ΔP(max)), and the maximum pressure rising rate ((dP/dt)max) decreased significantly, with the "tulip" flame disappearing and the flame getting brighter. The results show that the suppressing effect on methane explosion by ultrafine water/NaCl solution mist is influenced by the mist amount and methane concentration. With the increase of the mist amount, the pressure, and the flame speed both descended significantly. And when the mist amount reached 74.08 g/m(3) and 37.04 g/m(3), the flames of 6.5% and 13.5% methane explosions can be absolutely suppressed, respectively. All of results indicate that addition of NaCl can improve the suppression effect of ultrafine pure water mist on the methane explosions, and the suppression effect is considered due to the combination effect of physical and chemical inhibitions. PMID:25528229

  19. Suppression of methane/air explosion by ultrafine water mist containing sodium chloride additive.

    PubMed

    Cao, Xingyan; Ren, Jingjie; Zhou, Yihui; Wang, Qiuju; Gao, Xuliang; Bi, Mingshu

    2015-03-21

    The suppression effect of ultrafine mists on methane/air explosions with methane concentrations of 6.5%, 8%, 9.5%, 11%, and 13.5% were experimentally studied in a closed visual vessel. Ultrafine water/NaCl solution mist as well as pure water mist was adopted and the droplet sizes of mists were measured by phase doppler particle analyzer (PDPA). A high speed camera was used to record the flame evolution processes. In contrast to pure water mist, the flame propagation speed, the maximum explosion overpressure (ΔP(max)), and the maximum pressure rising rate ((dP/dt)max) decreased significantly, with the "tulip" flame disappearing and the flame getting brighter. The results show that the suppressing effect on methane explosion by ultrafine water/NaCl solution mist is influenced by the mist amount and methane concentration. With the increase of the mist amount, the pressure, and the flame speed both descended significantly. And when the mist amount reached 74.08 g/m(3) and 37.04 g/m(3), the flames of 6.5% and 13.5% methane explosions can be absolutely suppressed, respectively. All of results indicate that addition of NaCl can improve the suppression effect of ultrafine pure water mist on the methane explosions, and the suppression effect is considered due to the combination effect of physical and chemical inhibitions.

  20. Land use/land cover water quality nexus: quantifying anthropogenic influences on surface water quality.

    PubMed

    Wilson, Cyril O

    2015-07-01

    Anthropogenic forces widely influence the composition, configuration, and trend of land use and land cover (LULC) changes with potential implications for surface water quality. These changes have the likelihood of generating non-point source pollution with additional environmental implications for terrestrial and aquatic ecosystems. Monitoring the scope and trajectory of LULC change is pivotal for region-wide planning, tracking the sustainability of natural resources, and meeting the information needs of policy makers. A good comprehension of the dynamics of anthropogenic drivers (proximate and underlying) that influence such changes in LULC is important because any potential adverse change in LULC that may be inimical to sustainable water quality might be addressed at the anthropogenic driver level rather than the LULC change stage. Using a dense time stack of Landsat-5 Thematic Mapper images, a hydrologic water quality and socio-geospatial modeling framework, this study quantifies the role of anthropogenic drivers of LULC change on total suspended solids and total phosphorus concentrations in the Lower Chippewa River Watershed, Wisconsin, at three time steps-1990, 2000, and 2010. Results of the study demonstrated that proximate drivers of LULC change accounted for between 32 and 59% of the concentration and spatial distribution of total suspended solids, while the extent of phosphorus impairment attributed to the proximate drivers ranged between 31 and 42%. PMID:26065891

  1. Land use/land cover water quality nexus: quantifying anthropogenic influences on surface water quality.

    PubMed

    Wilson, Cyril O

    2015-07-01

    Anthropogenic forces widely influence the composition, configuration, and trend of land use and land cover (LULC) changes with potential implications for surface water quality. These changes have the likelihood of generating non-point source pollution with additional environmental implications for terrestrial and aquatic ecosystems. Monitoring the scope and trajectory of LULC change is pivotal for region-wide planning, tracking the sustainability of natural resources, and meeting the information needs of policy makers. A good comprehension of the dynamics of anthropogenic drivers (proximate and underlying) that influence such changes in LULC is important because any potential adverse change in LULC that may be inimical to sustainable water quality might be addressed at the anthropogenic driver level rather than the LULC change stage. Using a dense time stack of Landsat-5 Thematic Mapper images, a hydrologic water quality and socio-geospatial modeling framework, this study quantifies the role of anthropogenic drivers of LULC change on total suspended solids and total phosphorus concentrations in the Lower Chippewa River Watershed, Wisconsin, at three time steps-1990, 2000, and 2010. Results of the study demonstrated that proximate drivers of LULC change accounted for between 32 and 59% of the concentration and spatial distribution of total suspended solids, while the extent of phosphorus impairment attributed to the proximate drivers ranged between 31 and 42%.

  2. Foulant characteristics comparison in recycling cooling water system makeup by municipal reclaimed water and surface water in power plant.

    PubMed

    Ping, Xu; Jing, Wang; Yajun, Zhang; Jie, Wang; Shuai, Si

    2015-01-01

    Due to water shortage, municipal reclaimed water rather than surface water was replenished into recycling cooling water system in power plants in some cities in China. In order to understand the effects of the measure on carbon steel corrosion, characteristics of two kinds of foulant produced in different systems were studied in the paper. Differences between municipal reclaimed water and surface water were analyzed firstly. Then, the weight and the morphology of two kinds of foulant were compared. Moreover, other characteristics including the total number of bacteria, sulfate reducing bacteria, iron bacteria, extracellular polymeric substance (EPS), protein (PN), and polysaccharide (PS) in foulant were analyzed. Based on results, it could be concluded that microbial and corrosive risk would be increased when the system replenished by municipal reclaimed water instead of surface water.

  3. Foulant Characteristics Comparison in Recycling Cooling Water System Makeup by Municipal Reclaimed Water and Surface Water in Power Plant

    PubMed Central

    Ping, Xu; Jing, Wang; Yajun, Zhang; Jie, Wang; Shuai, Si

    2015-01-01

    Due to water shortage, municipal reclaimed water rather than surface water was replenished into recycling cooling water system in power plants in some cities in China. In order to understand the effects of the measure on carbon steel corrosion, characteristics of two kinds of foulant produced in different systems were studied in the paper. Differences between municipal reclaimed water and surface water were analyzed firstly. Then, the weight and the morphology of two kinds of foulant were compared. Moreover, other characteristics including the total number of bacteria, sulfate reducing bacteria, iron bacteria, extracellular polymeric substance (EPS), protein (PN), and polysaccharide (PS) in foulant were analyzed. Based on results, it could be concluded that microbial and corrosive risk would be increased when the system replenished by municipal reclaimed water instead of surface water. PMID:25893132

  4. Foulant characteristics comparison in recycling cooling water system makeup by municipal reclaimed water and surface water in power plant.

    PubMed

    Ping, Xu; Jing, Wang; Yajun, Zhang; Jie, Wang; Shuai, Si

    2015-01-01

    Due to water shortage, municipal reclaimed water rather than surface water was replenished into recycling cooling water system in power plants in some cities in China. In order to understand the effects of the measure on carbon steel corrosion, characteristics of two kinds of foulant produced in different systems were studied in the paper. Differences between municipal reclaimed water and surface water were analyzed firstly. Then, the weight and the morphology of two kinds of foulant were compared. Moreover, other characteristics including the total number of bacteria, sulfate reducing bacteria, iron bacteria, extracellular polymeric substance (EPS), protein (PN), and polysaccharide (PS) in foulant were analyzed. Based on results, it could be concluded that microbial and corrosive risk would be increased when the system replenished by municipal reclaimed water instead of surface water. PMID:25893132

  5. A water soluble additive to suppress respirable dust from concrete-cutting chainsaws: a case study.

    PubMed

    Summers, Michael P; Parmigiani, John P

    2015-01-01

    Respirable dust is of particular concern in the construction industry because it contains crystalline silica. Respirable forms of silica are a severe health threat because they heighten the risk of numerous respirable diseases. Concrete cutting, a common work practice in the construction industry, is a major contributor to dust generation. No studies have been found that focus on the dust suppression of concrete-cutting chainsaws, presumably because, during normal operation water is supplied continuously and copiously to the dust generation points. However, there is a desire to better understand dust creation at low water flow rates. In this case study, a water-soluble surfactant additive was used in the chainsaw's water supply. Cutting was performed on a free-standing concrete wall in a covered outdoor lab with a hand-held, gas-powered, concrete-cutting chainsaw. Air was sampled at the operator's lapel, and around the concrete wall to simulate nearby personnel. Two additive concentrations were tested (2.0% and 0.2%), across a range of fluid flow rates (0.38-3.8 Lpm [0.1-1.0 gpm] at 0.38 Lpm [0.1 gpm] increments). Results indicate that when a lower concentration of additive is used exposure levels increase. However, all exposure levels, once adjusted for 3 hours of continuous cutting in an 8-hour work shift, are below the Occupational Safety and Health Administration (OSHA) permissible exposure limit (PEL) of 5 mg/m(3). Estimates were made using trend lines to predict the fluid flow rates that would cause respirable dust exposure to exceed both the OSHA PEL and the American Conference of Governmental Industrial Hygienists (ACGIH®) threshold limit value (TLV).

  6. Occurrence and distribution of polycyclic aromatic hydrocarbons in reclaimed water and surface water of Tianjin, China.

    PubMed

    Cao, Zhonghong; Wang, Yuqiu; Ma, Yongmin; Xu, Ze; Shi, Guoliang; Zhuang, Yuanyi; Zhu, Tan

    2005-06-30

    Persistent organic pollutants (POPs) such as polycyclic aromatic hydrocarbons (PAHs) are of great concern due to their persistence, bioaccumulation and toxic effects. In this work, 16 PAHs included in the US Environmental Protection Agency's (EPA) priority pollutant list were analyzed using solid-phase extraction-gas chromatography-mass spectrometry (SPE-GC-MS) with a selected ion monitoring (SIM) mode. Reclaimed water and surface water sampling was undertaken in Tianjin, northern China. Total PAH concentrations varied from 1800 to 35,000 ng/L in surface waters (main rivers, tributaries, ditches, etc.) with mean value of 14,000 ng/L and from 227 to 600 ng/L in reclaimed water with mean value of 352 ng/L, respectively. The PAH profiles were dominated by low molecular weight PAHs (two- and three-ring components) in reclaimed water samples and surface water samples. These indicated that PAHs in reclaimed water and surface water might origin from oil or sewage contamination (petrogenic input). To elucidate sources, molecular indices based on indices among phenanthrene versus anthracene and fluoranthene versus pyrene were used to evaluate the possible source (pyrogenic and petrogenic sources, respectively) of PAH contamination in reclaimed water and surface water. The collected data showed that petrogenic input was predominant at almost all the stations investigated. To discriminate pattern differences and similarities among samples, principal component analysis (PCA) was performed using a correlation matrix. PCA revealed the latent relationships among all the surface water stations investigated and confirmed our analytical results. The analysis results of the ratios and PCA in this study showed that the ratios and PCA could be applied to the surface water investigation to some extent. PMID:15943926

  7. Non-additivity of molecule-surface van der Waals potentials from force measurements

    NASA Astrophysics Data System (ADS)

    Tautz, Stefan

    2014-03-01

    Van der Waals (vdW) forces act ubiquitously in condensed matter. Their description as an inherently quantum mechanical phenomenon was developed for single atoms and homogeneous macroscopic bodies by London, Casimir, and Lifshitz. For intermediate-sized objects like organic molecules an atomistic description is required, but explicit first principles calculations are very difficult since correlations between many interacting electrons have to be considered. Hence, semi-empirical correction schemes are often used that simplify the vdW interaction to a sum over atom-pair potentials. A similar gap exists between successful measurements of vdW and Casimir forces for single atoms on the one hand and macroscopic bodies on the other, as comparable experiments for molecules are absent. I will present experiments in which long-range vdW potentials between a series of related molecules and a metal surface have been determined experimentally. The experiments rely on the extremely sensitive force detection of an atomic force microscope in combination with its molecular manipulation capabilities. The results allow us to confirm the asymptotic force law and to quantify the non-additive part of the vdW interaction which is particularly challenging for theory. In the present case, cooperative effects account for 10% of the total interaction. This effect is of general validity in molecules and thus relevant at the intersection of chemistry, physics, biology, and materials science.

  8. Temperature Dependence of Cryogenic Ammonia-Water Ice Mixtures and Implications for Icy Satellite Surfaces

    NASA Technical Reports Server (NTRS)

    Dalton, J. B., III; Curchin, J. M.; Clark, R. N.

    2001-01-01

    Infrared spectra of ammonia-water ice mixtures reveal temperature-dependent absorption bands due to ammonia. These features, at 1.04, 2.0, and 2.25 microns, may shed light on the surface compositions of the Galilean and Saturnian satellites. Additional information is contained in the original extended abstract.

  9. Multilayer water condensation and desorption on hydrophobic and hydrophilic surfaces

    NASA Astrophysics Data System (ADS)

    Kasemo, Bengt; Lindroth, Trolle; Chakarov, Dinko

    2000-03-01

    We are studying water condensation and desorption on hydrophilic (e.g. Pt (111)) and hydrophilic (e.g. octane films on Pt(111) and graphite (0001)), at temperatures around 100-150K. On hydrophilic surfaces the behavior is well known from a manifold of earlier studies. On hydrophobic surfaces there are two qualitatively new behaviors; (i) The effective sticking coefficient can be much less than one because of the much weaker monomer H2O interaction with the surface, compared to hydrophilic surfaces. As a consequence the initial nucleation and growth rate of the film varies strongly with temperature and water vapor pressure (on hydrophobic surfaces) for the studied temperature range. (ii) The required mass of water to reach a coherent and completely covering film is much larger on the hydrophobic surface, i.e. the film morphology differs on the two types of surfaces. These differences are also reflected in differences in the phase transition from amorphous to crystallineof the ice film upon heating through the transition temperature. The measurements were primarily done by temperature programmed desorption. Theoretical modeling can semiquantitatively reproduce the nucleation and growth behavior on the hydrophobic substrate.

  10. Impact of Water Recovery from Wastes on the Lunar Surface Mission Water Balance

    NASA Technical Reports Server (NTRS)

    Fisher, John W.; Hogan, John Andrew; Wignarajah, Kanapathipi; Pace, Gregory S.

    2010-01-01

    Future extended lunar surface missions will require extensive recovery of resources to reduce mission costs and enable self-sufficiency. Water is of particular importance due to its potential use for human consumption and hygiene, general cleaning, clothes washing, radiation shielding, cooling for extravehicular activity suits, and oxygen and hydrogen production. Various water sources are inherently present or are generated in lunar surface missions, and subject to recovery. They include: initial water stores, water contained in food, human and other solid wastes, wastewaters and associated brines, ISRU water, and scavenging from residual propellant in landers. This paper presents the results of an analysis of the contribution of water recovery from life support wastes on the overall water balance for lunar surface missions. Water in human wastes, metabolic activity and survival needs are well characterized and dependable figures are available. A detailed life support waste model was developed that summarizes the composition of life support wastes and their water content. Waste processing technologies were reviewed for their potential to recover that water. The recoverable water in waste is a significant contribution to the overall water balance. The value of this contribution is discussed in the context of the other major sources and loses of water. Combined with other analyses these results provide guidance for research and technology development and down-selection.

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

    NASA Astrophysics Data System (ADS)

    Chemin, Rémi; Caulliez, Guillemette

    2015-04-01

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

  12. Influence of building resolution on surface water inundation outputs

    NASA Astrophysics Data System (ADS)

    Green, Daniel; Yu, Dapeng; Pattison, Ian

    2016-04-01

    Surface water (pluvial) flooding occurs when intense precipitation events overwhelm the drainage capacity of an area and excess water is unable to infiltrate into the ground or drain via natural or artificial drainage channels. In the UK, over 3 million properties are at risk from surface water flooding alone, accounting for approximately one third of all UK flood risk. This risk is predicted to increase due to future climatic changes resulting in an increasing magnitude and frequency of intense precipitation events. Numerical modelling is a well-established method of investigating surface water flood risk, allowing the researcher to gain an understanding of the depth, extent and severity of actual or hypothetical flood scenarios. Although numerical models allow the simulation of surface water inundation in a particular region, the model parameters (e.g. roughness, hydraulic conductivity) and resolution of topographic data have been shown to exert a profound influence on the inundation outputs which often leads to an over- or under-estimation of flood depths and extent without the use of external validation data to calibrate model outputs. Although previous research has demonstrated that model outputs are highly sensitive to Digital Elevation Model (DEM) mesh resolution, with flood inundation over large and complex topographies often requiring mesh resolutions coarser than the structural features (e.g. buildings) present within the study catchment, the specific influence of building resolution on surface flowpaths and connectivity during a surface water flood event has not been investigated. In this study, a LiDAR-derived DEM and OS MasterMap buildings layer of the Loughborough University campus, UK, were rasterized into separate 1m, 5m and 10m resolution layers. These layers were combined to create a series of Digital Surface Models (DSM) with varying, mismatching building and DEM resolutions (e.g. 1m DEM resolution, 10m building resolution, etc.) to understand

  13. Surface water pesticide modelling for decision support in drinking water production

    NASA Astrophysics Data System (ADS)

    Desmet, Nele; Dams, Jef; Bronders, Jan; Peleman, Gisèle; Verdickt, Liesbeth

    2015-04-01

    The occurrence of pesticides and other contaminants in river systems may compromise the use of surface water for drinking water production. To reduce the cost of removal of pesticides from the raw water, drinking water companies can: search for other raw water sources, invest in water storage capacity to overcome periods with high pesticide concentrations (often related to the application period), or impose measures to reduce the emission of pesticides to surface water (i.e. sustainable application strategies or use restrictions). To select the most appropriate water management options, the costs and effects of the aforementioned actions need to be evaluated. This evaluation requires knowledge on the concentrations and loads of pesticides at the point of drinking water abstraction, as well as insight in the contribution and the temporal variability of different sources or subbasins. In such a case, a modelling approach can assist in generating measurement-based datasets and to compare different scenarios for water management. We illustrate how a modelling approach can provide decision support for water management related to drinking water abstraction from surface water in a catchment that suffers from elevated pesticide concentrations. The study area is a water production center (WPC) located in northwestern Belgium. The WPC abstracts raw water from the river IJzer or from a natural pond and its connected streams. The available quantities as well as the quality of the water vary throughout the year. The WPC uses a reservoir of 3 million m³ to capture and store raw water to overcome periods with limited water availability and/or poor water quality. However, the pressure on water increases and in the future this buffering capacity might be no longer sufficient to fulfill the drinking water production demand. A surface water quality model for the area is set up using InfoWorks RS. The model is applied to obtain insight in the concentrations and loads at the different

  14. Surface activity of saponin from Quillaja bark at the air/water and oil/water interfaces.

    PubMed

    Wojciechowski, Kamil

    2013-08-01

    Surface activity of Sigma's Quillaja bark saponin (QBS) was studied by means of dynamic interfacial tension and surface dilational rheology at three fluid/fluid interfaces with the polarity of the non-aqueous phase increasing in the order: air/water, tetradecane/water and olive oil/water. The equilibrium interfacial tension isotherms were fitted to the generalized Frumkin model with surface compressibility for the air/water and tetradecane/water interfaces, whereas the isotherm for the third interface displays a more complex shape. Upon fast compression of a drop of concentrated "Sigma" QBS solution immersed in olive oil, a clearly visible and durable skin was formed. On the other hand, no skin formation was noticed at the air/water interface, and only a little at the tetradecane/water interface. Addition of a fatty acid, however, improved slightly the skin-formation ability of the QBS at the latter interface. The surface behavior of the QBS from Sigma was compared with that from Desert King, Int. ("Supersap"), employed in a recent study by Stanimirova et al. [22]. The two products exhibit different areas per molecule in the saturated adsorbed layer (0.37nm(2) vs. 1.19nm(2) for "Sigma" and "Supersap", respectively). Also their surface rheology is different: although both QBSs form predominantly elastic layers, for "Sigma" the surface storage modulus, εr=103mNm(-1), while for "Supersap" εr=73mNm(-1) at 10(-3)moll(-1) (i.e., around their cmc). The two saponin products exhibit also different ionic character, as proven by the acid-base titration of their aqueous solutions: QBS from Sigma is an ionic surfactant, while the "Supersap" from Desert King is a non-ionic one. PMID:23524082

  15. Surface activity of saponin from Quillaja bark at the air/water and oil/water interfaces.

    PubMed

    Wojciechowski, Kamil

    2013-08-01

    Surface activity of Sigma's Quillaja bark saponin (QBS) was studied by means of dynamic interfacial tension and surface dilational rheology at three fluid/fluid interfaces with the polarity of the non-aqueous phase increasing in the order: air/water, tetradecane/water and olive oil/water. The equilibrium interfacial tension isotherms were fitted to the generalized Frumkin model with surface compressibility for the air/water and tetradecane/water interfaces, whereas the isotherm for the third interface displays a more complex shape. Upon fast compression of a drop of concentrated "Sigma" QBS solution immersed in olive oil, a clearly visible and durable skin was formed. On the other hand, no skin formation was noticed at the air/water interface, and only a little at the tetradecane/water interface. Addition of a fatty acid, however, improved slightly the skin-formation ability of the QBS at the latter interface. The surface behavior of the QBS from Sigma was compared with that from Desert King, Int. ("Supersap"), employed in a recent study by Stanimirova et al. [22]. The two products exhibit different areas per molecule in the saturated adsorbed layer (0.37nm(2) vs. 1.19nm(2) for "Sigma" and "Supersap", respectively). Also their surface rheology is different: although both QBSs form predominantly elastic layers, for "Sigma" the surface storage modulus, εr=103mNm(-1), while for "Supersap" εr=73mNm(-1) at 10(-3)moll(-1) (i.e., around their cmc). The two saponin products exhibit also different ionic character, as proven by the acid-base titration of their aqueous solutions: QBS from Sigma is an ionic surfactant, while the "Supersap" from Desert King is a non-ionic one.

  16. The impact of groundwater depletions on groundwater surface water interactions and streamflow across the contiguous US

    NASA Astrophysics Data System (ADS)

    Condon, L. E.; Maxwell, R. M.

    2015-12-01

    Over the past 50 years, connections between climate change and streamflow trends have been observed in many regions of the Western US. However, much of the work to detect climate change signals in historical hydrologic records has focused on surface water changes in relatively undeveloped basins. While this is necessary to isolate any climate change signal from uncertain water management operations, it also excludes interactions with the concurrent human development that has occurred over the last 100 years. In highly utilized groundwater systems, such as the High Plains Aquifer, groundwater mining has already been linked to streamflow depletions at local to regional scales; but no prior studies have evaluated the role of groundwater declines in historical changes of groundwater surface water interactions at the continental scale. Here we isolate the influence of groundwater depletions from water management operations (e.g. irrigation and surface water diversions) to systematically evaluate how subsurface storage losses alter large-scale hydrologic interactions. Using a fully integrated groundwater surface water model of the contiguous US we simulate dynamic equilibrium conditions of a predevelopment system and a system with groundwater depletions equivalent to all of the groundwater development of the 20th century. Results illustrate the effect of persistent drawdown on streamflows, recharge and groundwater surface water exchanges across many spatial scales. In addition, we run transient simulations to evaluate the effect of these shifts on seasonal surface water variability. Simulations demonstrate the widespread trends in groundwater surface water interactions that have already resulted from ubiquitous groundwater mining in the United States and the potential for such changes to influence future response to climate variability.

  17. Modeling studies of geothermal systems with a free water surface

    SciTech Connect

    Bodvarsson, G.S.; Pruess, K.

    1983-12-01

    A numerical simulator was developed for the modeling of air-steam-water systems. The simulator was applied to various problems involving injection into or production from a geothermal reservoir in hydraulic communication with a shallow free-surface aquifer. First, a one-dimensional column problem is considered and the water level movement during exploitation is studied using different capillary pressure functions. Second, a two-dimensional radial model is used to study and compare reservoir depletion for cases with and without a free-surface aquifer. Finally, the contamination of a shallow free-surface aquifer due to cold water injection is investigated. The primary aim of these studies is to obtain an understanding of the response of a reservoir in hydraulic communication with a unconfined aquifer during exploitation or injection and to determine under which circumstances conventional modeling techniques (fully saturated systems) can be applied to such systems.

  18. Return of naturally sourced Pb to Atlantic surface waters

    PubMed Central

    Bridgestock, Luke; van de Flierdt, Tina; Rehkämper, Mark; Paul, Maxence; Middag, Rob; Milne, Angela; Lohan, Maeve C.; Baker, Alex R.; Chance, Rosie; Khondoker, Roulin; Strekopytov, Stanislav; Humphreys-Williams, Emma; Achterberg, Eric P.; Rijkenberg, Micha J. A.; Gerringa, Loes J. A.; de Baar, Hein J. W.

    2016-01-01

    Anthropogenic emissions completely overwhelmed natural marine lead (Pb) sources during the past century, predominantly due to leaded petrol usage. Here, based on Pb isotope measurements, we reassess the importance of natural and anthropogenic Pb sources to the tropical North Atlantic following the nearly complete global cessation of leaded petrol use. Significant proportions of up to 30–50% of natural Pb, derived from mineral dust, are observed in Atlantic surface waters, reflecting the success of the global effort to reduce anthropogenic Pb emissions. The observation of mineral dust derived Pb in surface waters is governed by the elevated atmospheric mineral dust concentration of the North African dust plume and the dominance of dry deposition for the atmospheric aerosol flux to surface waters. Given these specific regional conditions, emissions from anthropogenic activities will remain the dominant global marine Pb source, even in the absence of leaded petrol combustion. PMID:27678297

  19. The effect of surface water and wetting on gecko adhesion.

    PubMed

    Stark, Alyssa Y; Sullivan, Timothy W; Niewiarowski, Peter H

    2012-09-01

    Despite profound interest in the mechanics and performance of the gecko adhesive system, relatively few studies have focused on performance under conditions that are ecologically relevant to the natural habitats of geckos. Because geckos are likely to encounter surfaces that are wet, we used shear force adhesion measurements to examine the effect of surface water and toe pad wetting on the whole-animal performance of a tropical-dwelling gecko (Gekko gecko). To test the effect of surface wetting, we measured the shear adhesive force of geckos on three substrate conditions: dry glass, glass misted with water droplets and glass fully submerged in water. We also investigated the effect of wetting on the adhesive toe pad by soaking the toe pads prior to testing. Finally, we tested for repeatability of the adhesive system in each wetting condition by measuring shear adhesion after each step a gecko made under treatment conditions. Wetted toe pads had significantly lower shear adhesive force in all treatments (0.86 ± 0.09 N) than the control (17.96 ± 3.42 N), as did full immersion in water (0.44 ± 0.03 N). Treatments with droplets of water distributed across the surface were more variable and did not differ from treatments where the surface was dry (4.72 ± 1.59 N misted glass; 9.76 ± 2.81 N dry glass), except after the gecko took multiple steps. These findings suggest that surface water and the wetting of a gecko's adhesive toe pads may have significant consequences for the ecology and behavior of geckos living in tropical environments.

  20. Improved simulation of groundwater - surface water interaction in catchment models

    NASA Astrophysics Data System (ADS)

    teklesadik, aklilu; van Griensven, Ann; Anibas, Christian; Huysmans, Marijke

    2016-04-01

    Groundwater storage can have a significant contribution to stream flow, therefore a thorough understanding of the groundwater surface water interaction is of prime important when doing catchment modeling. The aim of this study is to improve the simulation of groundwater - surface water interaction in a catchment model of the upper Zenne River basin located in Belgium. To achieve this objective we used the "Groundwater-Surface water Flow" (GSFLOW) modeling software, which is an integration of the surface water modeling tool "Precipitation and Runoff Modeling system" (PRMS) and the groundwater modeling tool MODFLOW. For this case study, the PRMS model and MODFLOW model were built and calibrated independently. The PRMS upper Zenne River basin model is divided into 84 hydrological response units (HRUs) and is calibrated with flow data at the Tubize gauging station. The spatial discretization of the MODFLOW upper Zenne groundwater flow model consists of 100m grids. Natural groundwater divides and the Brussels-Charleroi canal are used as boundary conditions for the MODFLOW model. The model is calibrated using piezometric data. The GSFLOW results were evaluated against a SWAT model application and field observations of groundwater-surface water interactions along a cross section of the Zenne River and riparian zone. The field observations confirm that there is no exchange of groundwater beyond the Brussel-Charleroi canal and that the interaction at the river bed is relatively low. The results show that there is a significant difference in the groundwater simulations when using GSFLOW versus SWAT. This indicates that the groundwater component representation in the SWAT model could be improved and that a more realistic implementation of the interactions between groundwater and surface water is advisable. This could be achieved by integrating SWAT and MODFLOW.

  1. Radar image sequence analysis of inhomogeneous water surfaces

    NASA Astrophysics Data System (ADS)

    Seemann, Joerg; Senet, Christian M.; Dankert, Heiko; Hatten, Helge; Ziemer, Friedwart

    1999-10-01

    The radar backscatter from the ocean surface, called sea clutter, is modulated by the surface wave field. A method was developed to estimate the near-surface current, the water depth and calibrated surface wave spectra from nautical radar image sequences. The algorithm is based on the three- dimensional Fast Fourier Transformation (FFT) of the spatio- temporal sea clutter pattern in the wavenumber-frequency domain. The dispersion relation is used to define a filter to separate the spectral signal of the imaged waves from the background noise component caused by speckle noise. The signal-to-noise ratio (SNR) contains information about the significant wave height. The method has been proved to be reliable for the analysis of homogeneous water surfaces in offshore installations. Radar images are inhomogeneous because of the dependency of the image transfer function (ITF) on the azimuth angle between the wave propagation and the antenna viewing direction. The inhomogeneity of radar imaging is analyzed using image sequences of a homogeneous deep-water surface sampled by a ship-borne radar. Changing water depths in shallow-water regions induce horizontal gradients of the tidal current. Wave refraction occurs due to the spatial variability of the current and water depth. These areas cannot be investigated with the standard method. A new method, based on local wavenumber estimation with the multiple-signal classification (MUSIC) algorithm, is outlined. The MUSIC algorithm provides superior wavenumber resolution on local spatial scales. First results, retrieved from a radar image sequence taken from an installation at a coastal site, are presented.

  2. Hydroeconomic optimization of integrated water management and transfers under stochastic surface water supply

    NASA Astrophysics Data System (ADS)

    Zhu, Tingju; Marques, Guilherme Fernandes; Lund, Jay R.

    2015-05-01

    Efficient reallocation and conjunctive operation of existing water supplies is gaining importance as demands grow, competitions among users intensify, and new supplies become more costly. This paper analyzes the roles and benefits of conjunctive use of surface water and groundwater and market-based water transfers in an integrated regional water system where agricultural and urban water users coordinate supply and demand management based on supply reliability and economic values of water. Agricultural users optimize land and water use for annual and perennial crops to maximize farm income, while urban users choose short-term and long-term water conservation actions to maintain reliability and minimize costs. The temporal order of these decisions is represented in a two-stage optimization that maximizes the net expected benefits of crop production, urban conservation and water management including conjunctive use and water transfers. Long-term decisions are in the first stage and short-term decisions are in a second stage based on probabilities of water availability events. Analytical and numerical analyses are made. Results show that conjunctive use and water transfers can substantially stabilize farmer's income and reduce system costs by reducing expensive urban water conservation or construction. Water transfers can equalize marginal values of water across users, while conjunctive use minimizes water marginal value differences in time. Model results are useful for exploring the integration of different water demands and supplies through water transfers, conjunctive use, and conservation, providing valuable insights for improving system management.

  3. Enhancement of nitrate removal at the sediment-water interface by carbon addition plus vertical mixing.

    PubMed

    Chen, Xuechu; He, Shengbing; Zhang, Yueping; Huang, Xiaobo; Huang, Yingying; Chen, Danyue; Huang, Xiaochen; Tang, Jianwu

    2015-10-01

    Wetlands and ponds are frequently used to remove nitrate from effluents or runoffs. However, the efficiency of this approach is limited. Based on the assumption that introducing vertical mixing to water column plus carbon addition would benefit the diffusion across the sediment-water interface, we conducted simulation experiments to identify a method for enhancing nitrate removal. The results suggested that the sediment-water interface has a great potential for nitrate removal, and the potential can be activated after several days of acclimation. Adding additional carbon plus mixing significantly increases the nitrate removal capacity, and the removal of total nitrogen (TN) and nitrate-nitrogen (NO3(-)-N) is well fitted to a first-order reaction model. Adding Hydrilla verticillata debris as a carbon source increased nitrate removal, whereas adding Eichhornia crassipe decreased it. Adding ethanol plus mixing greatly improved the removal performance, with the removal rate of NO3(-)-N and TN reaching 15.0-16.5 g m(-2) d(-1). The feasibility of this enhancement method was further confirmed with a wetland microcosm, and the NO3(-)-N removal rate maintained at 10.0-12.0 g m(-2) d(-1) at a hydraulic loading rate of 0.5 m d(-1). PMID:25556005

  4. Hydrogeology and ground-water/surface water interactions in the Des Moines River valley, southwestern Minnesota, 1997-2001

    USGS Publications Warehouse

    Cowdery, Timothy K.

    2005-01-01

    Long-term withdrawals of water for public supplies may cause a net decrease in ground-water discharge to surface water. Water that does not evaporate, or that is not exported, is discharged to the Des Moines River but with changed water quality. Because ground-water and surface-water qualities in the study area are similar, the ground-water discharge probably has little effect on river water quality.

  5. Infiltration of pesticides in surface water into nearby drinking water supply wells

    NASA Astrophysics Data System (ADS)

    Malaguerra, F.; Albrechtsen, H.; Binning, P. J.

    2010-12-01

    Drinking water wells are often placed near streams because streams often overly permeable sediments and the water table is near the surface in valleys, and so pumping costs are reduced. The lowering of the water table by pumping wells can reverse the natural flow from the groundwater to the stream, inducing infiltration of surface water to groundwater and consequently to the drinking water well. Many attenuation processes can take place in the riparian zone, mainly due to mixing, biodegradation and sorption. However, if the water travel time from the surface water to the pumping well is too short, or if the compounds are poorly degradable, contaminants can reach the drinking water well at high concentrations, jeopardizing drinking water quality. Here we developed a reactive transport model to evaluate the risk of contamination of drinking water wells by surface water pollution. The model was validated using data of a tracer experiment in a riparian zone. Three compounds were considered: an older pesticide MCPP (Mecoprop) which is mobile and persistent, glyphosate (Roundup), a new biodegradable and strongly sorbed pesticide, and its degradation product AMPA. Global sensitivity analysis using the method of Morris was employed to identify the dominant model parameters. Results showed that the presence of an aquitard and its characteristics (degree of fracturing and thickness), pollutant properties and well depth are the crucial factors affecting the risk of drinking water well contamination from surface water. Global sensitivity analysis results were compared with rank correlation statistics between pesticide concentrations and geological parameters derived from a comprehensive database of Danish drinking water wells. Aquitard thickness and well depth are the most critical parameters in both the model and observed data.

  6. Zirconium fluoride glass - Surface crystals formed by reaction with water

    NASA Technical Reports Server (NTRS)

    Doremus, R. H.; Bansal, N. P.; Bradner, T.; Murphy, D.

    1984-01-01

    The hydrated surfaces of a zirconium barium fluoride glass, which has potential for application in optical fibers and other optical elements, were observed by scanning electron microscopy. Crystalline zirconium fluoride was identified by analysis of X-ray diffraction patterns of the surface crystals and found to be the main constituent of the surface material. It was also found that hydrated zirconium fluorides form only in highly acidic fluoride solutions. It is possible that the zirconium fluoride crystals form directly on the glass surface as a result of its depletion of other ions. The solubility of zirconium fluoride is suggested to be probably much lower than that of barium fluoride (0.16 g/100 cu cm at 18 C). Dissolution was determined to be the predominant process in the initial stages of the reaction of the glass with water. Penetration of water into the glass has little effect.

  7. Isotopic Tracers for Delineating Non-Point Source Pollutants in Surface Water

    SciTech Connect

    Davisson, M L

    2001-03-01

    This study tested whether isotope measurements of surface water and dissolved constituents in surface water could be used as tracers of non-point source pollution. Oxygen-18 was used as a water tracer, while carbon-14, carbon-13, and deuterium were tested as tracers of DOC. Carbon-14 and carbon-13 were also used as tracers of dissolved inorganic carbon, and chlorine-36 and uranium isotopes were tested as tracers of other dissolved salts. In addition, large databases of water quality measurements were assembled for the Missouri River at St. Louis and the Sacramento-San Joaquin Delta in California to enhance interpretive results of the isotope measurements. Much of the water quality data has been under-interpreted and provides a valuable resource to investigative research, for which this report exploits and integrates with the isotope measurements.

  8. Reconstruction of surfaces from mixed hydrocarbon and PEG components in water: responsive surfaces aid fouling release.

    PubMed

    Cho, Youngjin; Sundaram, Harihara S; Finlay, John A; Dimitriou, Michael D; Callow, Maureen E; Callow, James A; Kramer, Edward J; Ober, Christopher K

    2012-06-11

    Coatings derived from surface active block copolymers (SABCs) having a combination of hydrophobic aliphatic (linear hydrocarbon or propylene oxide-derived groups) and hydrophilic poly(ethlyene glycol) (PEG) side chains have been developed. The coatings demonstrate superior performance against protein adsorption as well as resistance to biofouling, providing an alternative to coatings containing fluorinated side chains as the hydrophobe, thus reducing the potential environmental impact. The surfaces were examined using dynamic water contact angle, captive air-bubble contact angle, atomic force microscopy, X-ray photoelectron spectroscopy, and near-edge X-ray absorption fine structure analysis. The PS(8K)-b-P(E/B)(25K)-b-PI(10K) triblock copolymer precursor (K3) initially dominated the dry surface. In contrast to previous studies with mixed fluorinated/PEG surfaces, these new materials displayed significant surface changes after exposure to water that allowed fouling resistant behavior. PEG groups buried several nanometers below the surface in the dry state were able to occupy the coating surface after placement in water. The resulting surface exhibits a very low contact angle and good antifouling properties that are very different from those of K3. The surfaces are strongly resistant to protein adsorption using bovine serum albumin as a standard protein challenge. Biofouling assays with sporelings of the green alga Ulva and cells of the diatom Navicula showed the level of adhesion was significantly reduced relative to that of a PDMS standard and that of the triblock copolymer precursor of the SABCs.

  9. The use of radar imagery for surface water investigations

    NASA Technical Reports Server (NTRS)

    Bryan, M. L.

    1981-01-01

    The paper is concerned with the interpretation of hydrologic features using L-band (HH) imagery collected by aircraft and Seasat systems. Areas of research needed to more precisely define the accuracy and repeatability of measurements related to the conditions of surfaces and boundaries of fresh water bodies are identified. These include: the definition of shoreline, the nature of variations in surface roughness across a water body and along streams and lake shores, and the separation of ambiguous conditions which appear similar to lakes.

  10. International Tables of the Surface Tension of Water

    NASA Astrophysics Data System (ADS)

    Vargaftik, N. B.; Volkov, B. N.; Voljak, L. D.

    1983-07-01

    This paper presents a table for the surface tension of water from 0.01 to 374 °C and an interpolating equation which represents the values in the table to well within their estimated uncertainties. The table of values and the interpolating equation are those recommended by the International Association for the Properties of Steam (IAPS) in its recent official release. The experimental measurements of the surface tension of water and their uncertainties are discussed, as is the development of the IAPS tables.

  11. Heterogeneous Nucleation of Naphthalene Vapor on Water Surface

    PubMed

    Smolík; Schwarz

    1997-01-15

    The evaporation of a water drop into a ternary gaseous mixture of air, steam, and naphthalene vapor was investigated. The experimental results were compared with a theoretical prediction based on a numerical solution of coupled boundary layer equations for heat and mass transfer from a drop moving in ternary gas. In the experiments the naphthalene vapor condensed on the water drop as a supercooled liquid even at temperatures far below the melting point of naphthalene. The condensation on drop surface is discussed in terms of classical theory of heterogeneous nucleation on smooth surfaces. PMID:9028892

  12. Pesticides in surface waters: distribution, trends, and governing factors

    USGS Publications Warehouse

    Larson, Steven J.; Capel, Paul D.; Majewski, Michael

    1997-01-01

    Pesticde use in agriculture and non-agriculture settings has increased dramatically over the last several decades. Concern about adverse effects on the environment and human health has spurred an enormous amount of research into their environmental behavior and fate. Pesticides in Surface Waters presents a comprehensive summary of this research. This book evaluates published studies that focus on measuring pesticide concentration. The studies chosen include peer reviewed scientific literature, government reports, laboratory studies, and those using microcosms and artificial streams and ponds. The authors used this information to develop their overview of pesticide contamination of surface waters. The exhaustive compilation of data along with the fundamental science make this book essential for those involved in pesticide use, environmental protection, water quality, and human or ecological risk assessment. Pesticides in Surface Waters covers the results of actual studies, sources of pesticides to surface water, fate and transport, and environmental significance. Hundreds of data-packed tables, maps, charts, and drawings illustrate the key points, making research and application easy and cost effective.

  13. Aluminum in acidic surface waters: chemistry, transport, and effects.

    PubMed Central

    Driscoll, C T

    1985-01-01

    Ecologically significant concentrations of Al have been reported in surface waters draining "acid-sensitive" watersheds that are receiving elevated inputs of acidic deposition. It has been hypothesized that mineral acids from atmospheric deposition have remobilized Al previously precipitated within the soil during soil development. This Al is then thought to be transported to adjacent surface waters. Dissolved mononuclear Al occurs as aquo Al, as well as OH-, F-, SO4(2-), and organic complexes. Although past investigations have often ignored non-hydroxide complexes of Al, it appears that organic and F complexes are the predominant forms of Al in dilute (low ionic strength) acidic surface waters. The concentration of inorganic forms of Al increases exponentially with decreases in solution pH. This response is similar to the theoretical pH dependent solubility of Al mineral phases. The concentration of organic forms of Al, however, is strongly correlated with variations in organic carbon concentration of surface waters rather than pH. Elevated concentrations of Al in dilute acidic waters are of interest because: Al is an important pH buffer; Al may influence the cycling of important elements like P, organic carbon, and trace metals; and Al is potentially toxic to aquatic organisms. An understanding of the aqueous speciation of Al is essential for an evaluation of these processes. PMID:3935428

  14. Aluminum in acidic surface waters: chemistry, transport, and effects.

    PubMed

    Driscoll, C T

    1985-11-01

    Ecologically significant concentrations of Al have been reported in surface waters draining "acid-sensitive" watersheds that are receiving elevated inputs of acidic deposition. It has been hypothesized that mineral acids from atmospheric deposition have remobilized Al previously precipitated within the soil during soil development. This Al is then thought to be transported to adjacent surface waters. Dissolved mononuclear Al occurs as aquo Al, as well as OH-, F-, SO4(2-), and organic complexes. Although past investigations have often ignored non-hydroxide complexes of Al, it appears that organic and F complexes are the predominant forms of Al in dilute (low ionic strength) acidic surface waters. The concentration of inorganic forms of Al increases exponentially with decreases in solution pH. This response is similar to the theoretical pH dependent solubility of Al mineral phases. The concentration of organic forms of Al, however, is strongly correlated with variations in organic carbon concentration of surface waters rather than pH. Elevated concentrations of Al in dilute acidic waters are of interest because: Al is an important pH buffer; Al may influence the cycling of important elements like P, organic carbon, and trace metals; and Al is potentially toxic to aquatic organisms. An understanding of the aqueous speciation of Al is essential for an evaluation of these processes.

  15. Surface-Heating Algorithm for Water at Nanoscale.

    PubMed

    Y D, Sumith; Maroo, Shalabh C

    2015-09-17

    A novel surface-heating algorithm for water is developed for molecular dynamics simulations. The validated algorithm can simulate the transient behavior of the evaporation of water when heated from a surface, which has been lacking in the literature. In this work, the algorithm is used to study the evaporation of water droplets on a platinum surface at different temperatures. The resulting contact angles of the droplets are compared to existing theoretical, numerical, and experimental studies. The evaporation profile along the droplet's radius and height is deduced along with the temperature gradient within the drop, and the evaporation behavior conforms to the Kelvin-Clapeyron theory. The algorithm captures the realistic differential thermal gradient in water heated at the surface and is promising for studying various heating/cooling problems, such as thin film evaporation, Leidenfrost effect, and so forth. The simplicity of the algorithm allows it to be easily extended to other surfaces and integrated into various molecular simulation software and user codes.

  16. Surface Modified Particles By Multi-Step Michael-Type Addition And Process For The Preparation Thereof

    DOEpatents

    Cook, Ronald Lee; Elliott, Brian John; Luebben, Silvia DeVito; Myers, Andrew William; Smith, Bryan Matthew

    2005-05-03

    A new class of surface modified particles and a multi-step Michael-type addition surface modification process for the preparation of the same is provided. The multi-step Michael-type addition surface modification process involves two or more reactions to compatibilize particles with various host systems and/or to provide the particles with particular chemical reactivities. The initial step comprises the attachment of a small organic compound to the surface of the inorganic particle. The subsequent steps attach additional compounds to the previously attached organic compounds through reactive organic linking groups. Specifically, these reactive groups are activated carbon—carbon pi bonds and carbon and non-carbon nucleophiles that react via Michael or Michael-type additions.

  17. Energy Landscape of Water and Ethanol on Silica Surfaces

    SciTech Connect

    Wu, Di; Guo, Xiaofeng; Sun, Hui; Navrotsky, Alexandra

    2015-06-26

    Fundamental understanding of small molecule–silica surface interactions at their interfaces is essential for the scientific, technological, and medical communities. We report direct enthalpy of adsorption (Δhads) measurements for ethanol and water vapor on porous silica glass (CPG-10), in both hydroxylated and dehydroxylated (hydrophobic) forms. Results suggest a spectrum of energetics as a function of coverage, stepwise for ethanol but continuous for water. The zero-coverage enthalpy of adsorption for hydroxylated silica shows the most exothermic enthalpies for both water (-72.7 ± 3.1 kJ/mol water) and ethanol (-78.0 ± 1.9 kJ/mol ethanol). The water adsorption enthalpy becomes less exothermic gradually until reaching its only plateau (-20.7 ± 2.2 kJ/mol water) reflecting water clustering on a largely hydrophobic surface, while the enthalpy of ethanol adsorption profile presents two well separated plateaus, corresponding to strong chemisorption of ethanol on adsorbate-free silica surface (-66.4 ± 4.8 kJ/mol ethanol), and weak physisorption of ethanol on ethanol covered silica (-4.0 ± 1.6 kJ/mol ethanol). On the other hand, dehydroxylation leads to missing water–silica interactions, whereas the number of ethanol binding sites is not impacted. The isotherms and partial molar properties of adsorption suggest that water may only bind strongly onto the silanols (which are a minor species on silica glass), whereas ethanol can interact strongly with both silanols and the hydrophobic areas of the silica surface.

  18. Energy Landscape of Water and Ethanol on Silica Surfaces

    DOE PAGES

    Wu, Di; Guo, Xiaofeng; Sun, Hui; Navrotsky, Alexandra

    2015-06-26

    Fundamental understanding of small molecule–silica surface interactions at their interfaces is essential for the scientific, technological, and medical communities. We report direct enthalpy of adsorption (Δhads) measurements for ethanol and water vapor on porous silica glass (CPG-10), in both hydroxylated and dehydroxylated (hydrophobic) forms. Results suggest a spectrum of energetics as a function of coverage, stepwise for ethanol but continuous for water. The zero-coverage enthalpy of adsorption for hydroxylated silica shows the most exothermic enthalpies for both water (-72.7 ± 3.1 kJ/mol water) and ethanol (-78.0 ± 1.9 kJ/mol ethanol). The water adsorption enthalpy becomes less exothermic gradually until reachingmore » its only plateau (-20.7 ± 2.2 kJ/mol water) reflecting water clustering on a largely hydrophobic surface, while the enthalpy of ethanol adsorption profile presents two well separated plateaus, corresponding to strong chemisorption of ethanol on adsorbate-free silica surface (-66.4 ± 4.8 kJ/mol ethanol), and weak physisorption of ethanol on ethanol covered silica (-4.0 ± 1.6 kJ/mol ethanol). On the other hand, dehydroxylation leads to missing water–silica interactions, whereas the number of ethanol binding sites is not impacted. The isotherms and partial molar properties of adsorption suggest that water may only bind strongly onto the silanols (which are a minor species on silica glass), whereas ethanol can interact strongly with both silanols and the hydrophobic areas of the silica surface.« less

  19. Water Surface Ripples Generated by the Turbulent Boundary Layer of a Surface-Piercing Moving Wall

    NASA Astrophysics Data System (ADS)

    Washuta, N.; Masnadi, N.; Duncan, J. H.

    2014-11-01

    Free surface ripples created by subsurface turbulence along a surface-piercing moving wall are studied experimentally. In this experiment, a meter-wide stainless steel belt travels horizontally in a loop around two rollers with vertically oriented axes, which are separated by 7.5 meters. One of the two 7.5-m-long belt sections between the rollers is in contact with the water in a large open-surface water tank and the water level is adjusted so that the top of the belt pierces the water free surface. The belt is launched from rest with a 3 g acceleration in order to quickly reach a steady state velocity. This belt motion creates a temporally evolving boundary layer analogous to the spatially evolving boundary layer created along the side of a ship hull moving at the belt velocity, with a length equivalent to the length of belt that has passed the measurement region. The water surface ripples generated by the subsurface turbulence are measured in a plane normal to the belt using a cinematic LIF technique. It is found that the overall RMS surface fluctuations increase linearly with belt speed and that the spatial distributions of the fluctuations show a sharp increase near the wall. The support of the Office of Naval Research is gratefully acknowledged.

  20. Shallow water surface gravity wave imaging, spectra and their use in shallow water dredging operations

    NASA Astrophysics Data System (ADS)

    Bostater, Charles R.; Yang, Bingyu

    2014-10-01

    Imaging of shallow waters using high resolution video imagery is described. Common to mono, stereo and trinocular imaging approaches from ground and airborne platforms is the need to validate the surface water wave field measurements, particularly the amplitude and specular reflectance of water surface small gravity waves. A technique for calibration and validation of water surface gravity wave field energy spectra is described. Results demonstrate the value of video imagery where water level staff gauges with approximately with 0.5 cm wave height accuracy are easily sensed using high definition videography. Essentially, a staff gauge placed in shallow water constructed from PVC materials with custom colored line coding are imaged at 30 H or high frame rates, followed by frame by frame analyses in order to detect the water level measured at 0.5 cm height intervals. The image based time series allow the development of shallow water gravity wave energy spectra using standard FFT analysis procedures. Spectral models based upon peak frequency, for example, are then used in a two dimensional water surface wave simulation model that generates radiative transfer based hyperspectral images of the water surface wave field. The simulated and observed water surface wave patch fields are compared by extracting vertical or horizontal transects within observed and simulated imagery. The approach allows one to developed spectral energy model probability distributions at low cost. The novel noncontact video sensing and image analysis methodology used to calibrate and validate shallow water gravity wave models yield a means for ultimately calculating bottom boundary velocities under measured or simulated wave fields. These boundary layer velocities can cause migration and horizontal particle fluxes (g cm-2 s-1), resuspension, settling, and increased turbidity during dredging operations, but not necessarily due to waterway dredging operations and activities.

  1. Characterization of typical surface effects in additive manufacturing with confocal microscopy

    NASA Astrophysics Data System (ADS)

    Grimm, Tobias; Wiora, Georg; Witt, Gerd

    2015-03-01

    The surfaces of laser-sintered and laser beam melted parts are characterized by typical surface effects and thus cause difficulties when using the popular tactile profilometry method and conventional two-dimensional surface parameters for analysis. Therefore, this study shows the potential of a new measurement approach by a confocal microscope and three-dimensional surface parameters. Within this study, a special focus is laid on the classification of different surface orientations and on a special issue in laser sintering: orange peel severity.

  2. THE USE OF DI WATER TO MITIGATE DUSTING FOR ADDITION OF DWPF FRIT TO THE SLURRY MIX EVAPORATOR

    SciTech Connect

    Hansen, E.

    2010-07-21

    objective of this task is to perform bench scale testing on various frits that have been used at DWPF or in test programs at SRNL to determine the quantity of de-ionized (DI) water required to mitigate dusting per mass basis of frit. The quantity of DI water required was determined visually by observing the effluent port of the mixer, and DI water addition was made to the point where no visible dust was observed leaving the effluent port. A total of eight different frits were selected for testing. Secondary objectives in this task include the following: (1) Video taping of the de-dusting procedure, (2) Particle size distribution analyses of the dry and wetted frits at the weight fraction of water required for de-dusting, (3) Plate flow tests to determine angle of flow and quantity of material remaining on plate at 90 degrees, (4) Microscopy of dry and wetted frit, and (5) Effect of excess water for selected frits on plate flow. The above analyses were performed within one hour of water addition, to minimize the effect of evaporative water losses. To better understand the size of dust particles, perform settling tests on selected frits and capture the fines. Analyze the fines for particle size distribution. Finally, it is expected that the surface area of frit is an important parameter in the quantity of water required for dust mitigation. An analysis of particle size distribution (PSD) data of as-received frit analyzed by SRNL over the past two to three years will be performed to determine the variation in the distribution of as-received frit. The following objectives were stated in the Technical Task Request4 as objectives that given adequate time would provide insight in helping DWPF in assessing equipment or processes for de-dusting and processing of dry frit. Due to time constraints, commercial methods for dedusting are provided. These results are detailed in section 3.7. Obtain design information from Hanford with respective to equipment used for dedusting. Suggestions

  3. Secondary functionalization of allyl-terminated GaP(111)A surfaces via heck cross-coupling metathesis, hydrosilylation, and electrophilic addition of bromine.

    PubMed

    Peczonczyk, Sabrina L; Brown, Elizabeth S; Maldonado, Stephen

    2014-01-14

    The functionalization of single crystalline gallium phosphide (GaP) (111)A surfaces with allyl groups has been performed using a sequential chlorine-activation/Grignard reaction process. Increased hydrophobicity following reaction of a GaP(111)A surface with C3H5MgCl was observed through water contact angle measurements. Infrared spectra of GaP(111)A samples after reaction with C3H5MgCl showed the asymmetric C═C and C═C-H modes diagnostic of surface-attached allyl groups. The stability of allyl-terminated GaP(111)A surfaces under ambient and aqueous conditions was investigated. XP spectra of allyl-terminated GaP(111)A highlighted a significant resistance against interfacial oxidation both in air and in water relative to the native interface. Electrochemical impedance spectroscopy indicated a change in the flat-band potential of allyl-terminated GaP(111)A electrodes immersed in water relative to native GaP(111)A surfaces. Further, the flat-band potentials for allyl-terminated electrodes were insensitive to changes in solution pH. The utility of surface-bound allyl groups for covalent secondary functionalization of GaP(111)A interfaces was assessed through three separate reactions: Heck cross-coupling metathesis, hydrosilylation, and electrophilic addition of bromine reactions. Addition of aryl groups across the olefins on allyl-terminated GaP(111)A via Heck cross coupling was performed and confirmed through high-resolution F 1s and C 1s XP spectra and IR spectra. Control experiments with GaP(111)A surfaces functionalized with short alkanes indicated no evidence for metathesis. Hydrosilylation reactions were separately performed. Si 2s XP spectra, in conjunction with infrared spectra, similarly showed secondary evidence of surface functionalization for allyl-terminated GaP(111)A but not for CH3-terminated GaP(111)A surfaces. Similar analyses showed electrophilic addition of Br2 across the terminal olefin on an allyl-terminated GaP(111)A surface after exposure to

  4. Constraints f