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Sample records for surface water ph

  1. Controls on pH in surface waters of northwestern European shelf seas

    Directory of Open Access Journals (Sweden)

    V. M. C. Rérolle

    2014-01-01

    Full Text Available We present here a high resolution surface water pH dataset obtained in the Northwest European shelf seas in summer 2011. This is the first time that pH has been measured at such a high spatial resolution (10 measurements h–1 in this region. The aim of our paper is to investigate the carbonate chemistry dynamics of the surface water using pH and ancillary data. The main processes controlling the pH distribution along the ship's transect, and their relative importance, were determined using a statistical approach. The study highlights the impact of biological activity, temperature and riverine inputs on the carbonate chemistry dynamics of the shelf seas surface water. For this summer cruise, the biological activity formed the main control of the pH distribution along the cruise transect. Variations in chlorophyll and nutrients explained 29% of the pH variance along the full transect and as much as 68% in the northern part of the transect. In contrast, the temperature distribution explained ca. 50% of the pH variation in the Skagerrak region. Riverine inputs were evidenced by high dissolved organic carbon (DOC levels in the Strait of Moyle (northern Irish Sea and the southern North Sea with consequent remineralisation processes and a reduction in pH. The DOC distribution described 15% of the pH variance along the full transect. This study highlights the high spatial variability of the surface water pH in shelf seawaters where a range of processes simultaneously impacts the carbonate chemistry.

  2. Surface water pH variations and trends in China from 2004 to 2014.

    Science.gov (United States)

    Qiao, Yinhuan; Feng, Jianfeng; Liu, Xia; Wang, Wei; Zhang, Pei; Zhu, Lin

    2016-07-01

    With economic development and the increase of energy consumption, surface water acidification has been a potential environmental concern in China. Here, we analyzed variations and trends in surface water pH of 73 sites from ten river basins in China from 2004 to 2014 with nonparametric Seasonal Kendall test method. Our analysis showed that the variations of surface water pH in China ranged from 6.5 to 9.0 in the past decade (2004-2014), which satisfied the water quality criteria in pH for protection of aquatic ecosystems in China (6.0-9.0) and USA (6.5-9.0). However, significant decreasing trends in surface water pH were found in 31 monitoring sites, which were mainly located in Haihe River, Taihu Lake and Yangtze River, while the pH value showed significant increasing trends in 22 sites, which mainly were located in Songhua River and Pearl River. Our results suggested the increased potential acidification of susceptible water bodies in China. Besides the control policy of sulfur dioxide (SO2) emissions, the emissions of nitrous oxides (NOx) should also be reduced to protect the aquatic systems in China.

  3. Spatial variability of surface-sediment porewater pH and related water-column characteristics in deep waters of the northern South China Sea

    Science.gov (United States)

    Shao, Changgao; Sui, Yi; Tang, Danling; Legendre, Louis

    2016-12-01

    This study analyzes the pH of surface-sediment porewater (i.e. 2-3 cm below the water-sediment interface), and concentrations of CaCO3 and organic carbon (OC) in 1192 sediment cores from the northern South China Sea, in water depths ranging from 137 to 3702 m. This is the first study in the literature to analyze the large-scale spatial variability of deep-water surface-sediment pH over a large ocean basin. The data showed strong spatial variations in pH. The lowest pH values (Pearl and Red Rivers. Moderately low pH values (generally 7.3-7.5) occurred in two other areas: a submarine canyon, where sediments originated partly from the Pearl River and correspond to a paleo-delta front during the last glacial period; and southwest of Taiwan Island, where waters are affected by the northern branch of the Kuroshio intrusion current (KIC) and runoff from Taiwan rivers. The surface sediments with the highest pH (⩾7.5, and up to 8.3) were located in a fourth area, which corresponded to the western branch of the KIC where sediments have been intensively eroded by bottom currents. The pH of surface-sediment porewater was significantly linearly related to water depth, bottom-water temperature, and CaCO3 concentration (p < 0.05 for the whole sampling area). This study shows that the pH of surface-sediment porewater can be sensitive to characteristics of the overlying water column, and suggests that it will respond to global warming as changes in surface-ocean temperature and pH progressively reach deeper waters.

  4. Variability of shelf sea pH and surface water CO2 in response to North Atlantic Oscillation forcing

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    Salt, L.; Thomas, H.; Prowe, A. E. F.; Borges, A. V.; de Baar, H. J. W.

    2012-04-01

    High biological activity causes a distinct seasonality of surface water pH in the North Sea, which has been identified as a strong sink for atmospheric CO2 via a particularly effective shelf pump. The intimate connection between the North Sea and the North Atlantic suggests that the variability of the CO2 system of the North Atlantic Ocean may in part be responsible for the observed, but hitherto poorly understood variability of pH and CO2 in the North Sea. Here we investigate the role of the North Atlantic Oscillation (NAO), the dominant climate mode for the North Atlantic hemisphere in governing this variability. Based on three extensive observational records covering the relevant levels of the NAO index, we provide evidence that the North Sea pH and CO2 system strongly responds to external and internal expressions of the NAO. We argue that under NAO+ conditions higher rates of inflow of water from the North Atlantic Ocean limits seasonal shoaling of the summer mixed layer in the northern North Sea, diminishing the biological potential to lower pCO2 and raise pH. In addition the faster circulation of the North Sea enhances the shelf pump efficiency. These clear patterns are obscured by changing properties of the North Sea waters, masking or enforcing these effects on various time scales. Such controls indicate that inter-annual trends in the North Sea CO2 system must be carefully examined with consideration to the North Atlantic Oscillation.

  5. A surface-enhanced infrared absorption spectroscopic study of pH dependent water adsorption on Au

    Science.gov (United States)

    Dunwell, Marco; Yan, Yushan; Xu, Bingjun

    2016-08-01

    The potential dependent behavior of near-surface water on Au film electrodes in acidic and alkaline solutions is studied using a combination of attenuated total reflectance surface enhanced infrared spectroscopy and chronoamperometry. In acid, sharp νOH peaks appear at 3583 cm- 1 at high potentials attributed to non-H-bonded water coadsorbed in the hydration sphere of perchlorate near the electrode surface. Adsorbed hydronium bending mode at near 1680 cm- 1 is observed at low potentials in low pH solutions (1.4, 4.0, 6.8). At high pH (10.0, 12.3), a potential-dependent OH stretching band assigned to adsorbed hydroxide emerges from 3400-3506 cm- 1. The observation of adsorbed hydroxide, even on a weakly oxophilic metal such as Au, provides the framework for further studies of hydroxide adsorption on other electrodes to determine the role of adsorbed hydroxide on important reactions such as the hydrogen oxidation reaction.

  6. Chemical equilibrium modeling of organic acids, pH, aluminum, and iron in Swedish surface waters.

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    Sjöstedt, Carin S; Gustafsson, Jon Petter; Köhler, Stephan J

    2010-11-15

    A consistent chemical equilibrium model that calculates pH from charge balance constraints and aluminum and iron speciation in the presence of natural organic matter is presented. The model requires input data for total aluminum, iron, organic carbon, fluoride, sulfate, and charge balance ANC. The model is calibrated to pH measurements (n = 322) by adjusting the fraction of active organic matter only, which results in an error of pH prediction on average below 0.2 pH units. The small systematic discrepancy between the analytical results for the monomeric aluminum fractionation and the model results is corrected for separately for two different fractionation techniques (n = 499) and validated on a large number (n = 3419) of geographically widely spread samples all over Sweden. The resulting average error for inorganic monomeric aluminum is around 1 µM. In its present form the model is the first internally consistent modeling approach for Sweden and may now be used as a tool for environmental quality management. Soil gibbsite with a log *Ks of 8.29 at 25°C together with a pH dependent loading function that uses molar Al/C ratios describes the amount of aluminum in solution in the presence of organic matter if the pH is roughly above 6.0.

  7. Impact of pH, dissolved inorganic carbon, and polyphosphates for the initial stages of water corrosion of copper surfaces investigated by AFM and NEXAFS

    Science.gov (United States)

    Nanoscale studies at the early stages of the exposure of copper surfaces after systematic treatments in synthesized water solutions can provide useful information about corrosion processes. The corrosion and passivation of copper surfaces as influenced by pH, dissolved inorganic ...

  8. Ocean circulation and biogeochemistry moderate interannual and decadal surface water pH changes in the Sargasso Sea

    Science.gov (United States)

    Nathalie F. Goodkin,; Bo-Shian Wang,; Chen-Feng You,; Konrad Hughen,; Prouty, Nancy G.; Bates, Nicholas; Scott Doney,

    2015-01-01

    The oceans absorb anthropogenic CO2 from the atmosphere, lowering surface ocean pH, a concern for calcifying marine organisms. The impact of ocean acidification is challenging to predict as each species appears to respond differently and because our knowledge of natural changes to ocean pH is limited in both time and space. Here we reconstruct 222 years of biennial seawater pH variability in the Sargasso Sea from a brain coral, Diploria labyrinthiformis. Using hydrographic data from the Bermuda Atlantic Time-series Study and the coral-derived pH record, we are able to differentiate pH changes due to surface temperature versus those from ocean circulation and biogeochemical changes. We find that ocean pH does not simply reflect atmospheric CO2 trends but rather that circulation/biogeochemical changes account for >90% of pH variability in the Sargasso Sea and more variability in the last century than would be predicted from anthropogenic uptake of CO2 alone.

  9. Investigation by response surface methodology of the combined effect of pH and composition of water-methanol mixtures on the stability of curcuminoids.

    Science.gov (United States)

    D'Archivio, Angelo Antonio; Maggi, Maria Anna

    2017-03-15

    Response surface methodology, coupled to a full factorial three-level experimental design, was applied to investigate the combined influence of pH (between 7.0 and 8.6) and composition of methanol-water mixtures (between 30 and 70% v/v of methanol content) on the stability of curcumin and its analogues demethoxycurcumin and bisdemethoxycurcumin. The response plots revealed that addition of methanol noticeably improved the stability of curcuminoids, this effect being both pH- and structure-dependent. In the central point of the experimental domain, half-life times of curcumin, demethoxycurcumin and bisdemethoxycurcumin were 3.8±0.2, 27±2 and 251±17h, respectively. Stability of curcuminoids increased at lower pH and higher methanol content and decreased in the opposite vertex of the experimental domain. These results can be interpreted by assuming that addition of methanol to water produces a different variation of pH of the medium and apparent pKa values of the ionisable groups of curcuminoids.

  10. Surface Water & Surface Drainage

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    Earth Data Analysis Center, University of New Mexico — This data set contains boundaries for all surface water and surface drainage for the state of New Mexico. It is in a vector digital data structure digitized from a...

  11. Blending Canal Surfaces Based on PH Curves

    Institute of Scientific and Technical Information of China (English)

    Chen-Dong Xu; Fa-Lai Chen

    2005-01-01

    In this paper, a new method for blending two canal surfaces is proposed. The blending surface is itself a generalized canal surface, the spine curve of which is a PH (Pythagorean-Hodograph) curve. The blending surface possesses an attractive property - its representation is rational. The method is extensible to blend general surfaces as long as the blending boundaries are well-defined.

  12. The complementary power of pH and lake-water organic carbon reconstructions for discerning the influences on surface waters across decadal to millennial time scales

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    P. Rosén

    2011-09-01

    Full Text Available Lysevatten, a lake in southwest Sweden, has experienced both acidification and recent changes in the amount of lake-water organic carbon (TOC, both causing concern across Europe and North America. A range of paleolimnological tools – diatom-inferred pH, inferred lake-water TOC from visible-near-infrared spectroscopy (VNIRS, multi-element geochemistry and pollen analysis, combined with geochemical modeling were used to reconstruct the lake's chemistry and surroundings back to the most recent deglaciation 12 500 years ago. The results reveal that the recent anthropogenic impacts are similar in magnitude to the long-term variation driven by natural catchment changes and early agricultural land use occurring over centuries and millennia. The combined reconstruction of both lake-water TOC and lithogenic element delivery can explain the major changes in lake-water pH and modeled acid neutralizing capacity during the past 12 500 years. The results raise important questions regarding what precisely comprises "reference" conditions (i.e., free from human impacts as defined in the European Water Framework Directive.

  13. Ikaite crystals in melting sea ice - implications for pCO(2) and pH levels in Arctic surface waters

    DEFF Research Database (Denmark)

    Rysgaard, Søren; Glud, Ronnie N.; Lennert, K.

    2012-01-01

    that multiple chemical transformations occur in sea ice with a possible effect on CO2 and pH conditions in surface waters. Here, we report on biogeochemical conditions, microscopic examinations and x-ray diffraction analysis of single crystals from a melting 1.7 km(2) (0.5-1m thick) drifting ice floe......, melt reduced the ice floe thickness by 0.2m per week and resulted in an estimated 3.8 ppm decrease of pCO(2) in the ocean surface mixed layer. This corresponds to an air-sea CO2 uptake of 10.6 mmol m(-2) sea ice d(-1) or to 3.3 ton km(-2) ice floe week(-1). This is markedly higher than the estimated...... primary production within the ice floe of 0.3-1.3 mmol m(-2) sea ice d(-1). Finally, the presence of ikaite in sea ice and the dissolution of the mineral during melting of the sea ice and mixing of the melt water into the surface oceanic mixed layer accounted for half of the estimated pCO(2) uptake...

  14. Ikaite crystals in melting sea ice – implications for pCO2 and pH levels in Arctic surface waters

    DEFF Research Database (Denmark)

    Rysgaard, Søren; Glud, R.N.; Lennert, K.

    2012-01-01

    chemical transformations occur in sea ice with a possible effect on CO 2 and pH conditions in surface waters. Here, we report on biogeochemical conditions, microscopic examinations and x-ray diffraction analysis of single crystals from a melting 1.7 km 2 (0.5-1 m thick) drifting ice floe in the Fram Strait...... during summer. Our findings show that ikaite crystals are present throughout the sea ice but with larger crystals appearing in the upper ice layers. Ikaite crystals placed at elevated temperatures disintegrated into smaller crystallites and dissolved. During our field campaign in late June, melt reduced...... within the ice floe of 0.3-1.3 mmol m -2 sea ice d -1. Finally, the presence of ikaite in sea ice and the dissolution of the mineral during melting of the sea ice and mixing of the melt water into the surface oceanic mixed layer accounted for half of the estimated pCO 2 uptake. © Author(s) 2012....

  15. Ikaite crystals in melting sea ice – implications for pCO2 and pH levels in Arctic surface waters

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    R. J. G. Leakey

    2012-08-01

    Full Text Available A major issue of Arctic marine science is to understand whether the Arctic Ocean is, or will be, a source or sink for air–sea CO2 exchange. This has been complicated by the recent discoveries of ikaite (a polymorph of CaCO3·6H2O in Arctic and Antarctic sea ice, which indicate that multiple chemical transformations occur in sea ice with a possible effect on CO2 and pH conditions in surface waters. Here, we report on biogeochemical conditions, microscopic examinations and x-ray diffraction analysis of single crystals from a melting 1.7 km2 (0.5–1 m thick drifting ice floe in the Fram Strait during summer. Our findings show that ikaite crystals are present throughout the sea ice but with larger crystals appearing in the upper ice layers. Ikaite crystals placed at elevated temperatures disintegrated into smaller crystallites and dissolved. During our field campaign in late June, melt reduced the ice floe thickness by 0.2 m per week and resulted in an estimated 3.8 ppm decrease of pCO2 in the ocean surface mixed layer. This corresponds to an air–sea CO2 uptake of 10.6 mmol m−2 sea ice d−1 or to 3.3 ton km−2 ice floe week−1. This is markedly higher than the estimated primary production within the ice floe of 0.3–1.3 mmol m−2 sea ice d−1. Finally, the presence of ikaite in sea ice and the dissolution of the mineral during melting of the sea ice and mixing of the melt water into the surface oceanic mixed layer accounted for half of the estimated pCO2 uptake.

  16. Ikaite crystals in melting sea ice - implications for pCO(2) and pH levels in Arctic surface waters

    DEFF Research Database (Denmark)

    Rysgaard, Søren; Glud, Ronnie N.; Lennert, K.

    2012-01-01

    A major issue of Arctic marine science is to understand whether the Arctic Ocean is, or will be, a source or sink for air-sea CO2 exchange. This has been complicated by the recent discoveries of ikaite (a polymorph of CaCO3 center dot 6H(2)O) in Arctic and Antarctic sea ice, which indicate...... that multiple chemical transformations occur in sea ice with a possible effect on CO2 and pH conditions in surface waters. Here, we report on biogeochemical conditions, microscopic examinations and x-ray diffraction analysis of single crystals from a melting 1.7 km(2) (0.5-1m thick) drifting ice floe......, melt reduced the ice floe thickness by 0.2m per week and resulted in an estimated 3.8 ppm decrease of pCO(2) in the ocean surface mixed layer. This corresponds to an air-sea CO2 uptake of 10.6 mmol m(-2) sea ice d(-1) or to 3.3 ton km(-2) ice floe week(-1). This is markedly higher than the estimated...

  17. Ikaite crystals in melting sea ice – implications for pCO2 and pH levels in Arctic surface waters

    Directory of Open Access Journals (Sweden)

    R. J. G. Leakey

    2012-03-01

    Full Text Available A major issue of Arctic marine science is to understand whether the Arctic Ocean is, or will be, a source or sink for air-sea CO2 exchange. This has been complicated by the recent discoveries of ikaite (CaCO3·6H2O in Arctic and Antarctic sea ice, which indicate that multiple chemical transformations occur in sea ice with a possible effect on CO2 and pH conditions in surface waters. Here we report on biogeochemical conditions, microscopic examinations and x-ray diffraction analysis of single crystals from an actively melting 1.7 km2 (0.5–1 m thick drifting ice floe in the Fram Strait during summer. Our findings show that ikaite crystals are present throughout the sea ice but with larger crystals appearing in the upper ice layers. Ikaite crystals placed at elevated temperatures gradually disintegrated into smaller crystallites and dissolved. During our field campaign in late June, melt reduced the ice flow thickness by ca. 0.2 m per week and resulted in an estimated 1.6 ppm decrease of pCO2 in the ocean surface mixed layer. This corresponds to an air-sea CO2 uptake of 11 mmol m−2 sea ice d−1 or to 3.5 ton km−2 ice floe week−1.

  18. Ikaite crystals in melting sea ice – implications for pCO2 and pH levels in Arctic surface waters

    DEFF Research Database (Denmark)

    Rysgaard, Søren; Glud, R.N.; Lennert, K.

    2012-01-01

    A major issue of Arctic marine science is to understand whether the Arctic Ocean is, or will be, a source or sink for air-sea CO 2 exchange. This has been complicated by the recent discoveries of ikaite (a polymorph of CaCO 3•6H 2O) in Arctic and Antarctic sea ice, which indicate that multiple...... chemical transformations occur in sea ice with a possible effect on CO 2 and pH conditions in surface waters. Here, we report on biogeochemical conditions, microscopic examinations and x-ray diffraction analysis of single crystals from a melting 1.7 km 2 (0.5-1 m thick) drifting ice floe in the Fram Strait...... during summer. Our findings show that ikaite crystals are present throughout the sea ice but with larger crystals appearing in the upper ice layers. Ikaite crystals placed at elevated temperatures disintegrated into smaller crystallites and dissolved. During our field campaign in late June, melt reduced...

  19. Adsorption of natural organic matter and disinfection byproduct precursors from surface water onto TiO2 nanoparticles: pH effects, isotherm modelling and implications for using TiO2 for drinking water treatment.

    Science.gov (United States)

    Gora, Stephanie L; Andrews, Susan A

    2017-05-01

    Titanium dioxide is a photocatalyst that can remove organic contaminants of interest to the drinking water treatment industry, including natural organic matter (NOM) and disinfection byproduct (DBP) precursors. The photocatalytic reaction occurs in two steps: adsorption of the contaminant followed by degradation of the adsorbed contaminant upon irradiation with UV light. The second part of this process can lead to the formation of reactive intermediates and negative impacts on treated water quality, such as increased DBP formation potential (DBPfp). Adsorption alone does not result in the formation of reactive intermediates and thus may prove to be a safe way to incorporate TiO2 into drinking water treatment processes. The goal of this study was to expand on the current understanding of NOM adsorption on TiO2 and examine it in a drinking water context by observing NOM adsorption from real water sources and evaluating the effects of the resulting reductions on the DBPfp of the treated water. Bottle point isotherm tests were conducted with raw water from two Canadian water treatment plants adjusted to pH 4, pH 6 and pH 8 and dosed with TiO2 nanoparticles. The DOC results were a good fit to a modified Freundlich isotherm. DBP precursors and liquid chromatography with organic carbon detection NOM fractions associated with DBP formation were removed to some extent at all pHs, but most effectively at pH 4. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Detection and aggregation of the antitumoral drug parietin in ethanol/water mixture and on plasmonic metal nanoparticles studied by surface-enhanced optical spectroscopy: Effect of pH and ethanol concentration.

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    Lopez-Tobar, Eduardo; Verebova, Valeria; Blascakova, Ludmila; Jancura, Daniel; Fabriciova, Gabriela; Sanchez-Cortes, Santiago

    2016-04-15

    In the present paper, we have investigated the effect of ethanol in aqueous media, the pH and the presence of Ag nanoparticles (NPs) on the aggregation processes of the antitumoral anthraquinone parietin in aqueous media and on the metal surface. UV-visible absorption, fluorescence and Raman spectra of parietin were used for such purpose. The present study provides information about the deprotonation and molecular aggregation processes occurring in parietin under different environments: ethanol/water mixture and when adsorbed onto Ag nanoparticles. The effect of ethanol on the optical properties of parietin in alcohol-water mixtures was also investigated at different ethanol concentrations with the time. For the case of the adsorption and organization of parietin molecules on the surface of Ag NPs, special attention was paid to the use of surface-enhanced optical techniques, SEF (surface-enhanced fluorescence) and SERS (surface-enhanced Raman scattering), for the characterization of the parietin aggregates and the ionization of the molecule on the surface. In particular, we have studied the variation of the SEF signal with the pH, which depends on the molecular organization of the molecule on the surface. Furthermore, a detailed analysis of the SERS spectra at different pH was accomplished and the main Raman bands of the protonated, mono-deprotonated and di-deprotonated parietin were identified. Finally, the second ionization pK of parietin on metal NPs was deduced from the SERS spectra. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Effects of different substrates in the mitigation of algae-induced high pH wastewaters in a pilot-scale free water surface wetland system.

    Science.gov (United States)

    Jin, Meng; Champagne, Pascale; Hall, Geoffrey

    2017-01-01

    Waste stabilization ponds (WSPs), as part of municipal wastewater treatment strategies, can exhibit variability in performance due to climatic conditions. Under elevated temperature and strong solar radiation, algal blooms and subsequent high pH effluents have often been observed. In this study, four substrates (gravel, peat, organic mulch, and topsoil) were evaluated for their ability to attenuate high pH effluents from a WSP. Synthetic wastewater with pH > 9.5, and low organic and nutrient loadings, was used to mimic algal-induced high pH effluents in 72 L rectangular bench-scale superficial constructed wetland configuration reactors. Peat exhibited the highest attenuation ability, where the effluent pH decreased substantially from 10.3 to 7.7, primarily due to its high organic contents. Peat also removed 53.7% of the influent total phosphorus, which could effectively limit algal growth. No statistically significant differences were discovered among gravel, topsoil, and organic mulch in terms of pH attenuation. Topsoil and organic mulch both have a relatively high alkalinity, making them ideal to maintain consistent pH levels. However, naturally high chemical oxygen demand levels in organic mulch raised concerns in the leaching of these compounds into the treated wastewater, making it less appealing for systems with low organic loading.

  2. Surface-water surveillance

    Energy Technology Data Exchange (ETDEWEB)

    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).

  3. Surface Water in Hawaii

    Science.gov (United States)

    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.

  4. WATER HARDNESS AS AN IMPORTANT PARAMETER OF PH

    Directory of Open Access Journals (Sweden)

    Žigmund Tóth

    2013-02-01

    Full Text Available Quality of final product is to great extent influenced by intermediate products that are formed during beer production. In addition quality of pH is one of the most important properties that forms suitable medium for activity of enzymes complexes that have crucial influence on character of produced wort. Moreover enzymes influence the yield of production process and quality of final product as well. Quality of boiling water and especially its hardness have crucial task in terms of keeping optimal qualitative parameters. Water hardness is given by amount of salts, mainly calcium and magnesium salts. It is expressed as absolute hardness which is given by sum of temporary (carbonate and permanent (noncarbonate hardness. In our work we solved the effect of total water hardness on final pH of various intermediate products. We used different water samples and we prepared variants of total hardness by stirring of unpurified water with distilled water thus we achieved various values of hardness. For comparison we prepared several brews with regard to combinations of unpurified water and distilled water. Higher pH of boiling water was caused due to higher water alkalinity that negatively affected enzyme complex present in used malt. Presence of hydrogenphosphates in used malt had high buffering ability and pH lowering ability. Such unfavorable result could be adjust by use of various additions of acidulates that would have in great extent influence on beer final price therefore boiling water adjustment seems to be the most acceptable approach.

  5. MANUFACTURE OF FIBER OPTIC SENSORS TO MEASURE THE PH WATER

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    Bushra R. Mahdi

    2016-07-01

    Full Text Available A fiber-optic pH sensor based on evanescent wave penetration is presented. Evanescent wave penetration is generated by removing the clad and contact the core with the solution. Testing samples were perpetrated by add a strong acid (HCL or a strong base (NaOH at distilled water to produce different value of pH (from 4 to 13. To determine the absorption or transmission of the evanescent waves, that generate after where obtained on appropriate calibration curve to determine a wide range of pH, by using pH indicators. Where using methyl red, by add fixed amounts of this dyes to the water samples were obtained on samples with colors vary with pH values. Calculate the transmission and absorption with draw a relationship between the transmissions or absorption with the pH values, to obtain on suitable curves, considered as calibration curves. Calibration curve for methyl red is best, where extends (from 4 to 12 for pH value. Can calculate the pH value for any water sample to tested, by the add the same ratios of the organic dyes it used.

  6. Variability in pH, fCO 2, oxygen and flux of CO 2 in the surface water along a transect in the Atlantic sector of the Southern Ocean

    Science.gov (United States)

    Chierici, Melissa; Fransson, Agneta; Turner, David R.; Pakhomov, E. A.; Froneman, P. W.

    2004-11-01

    Underway sampling and measurements of pH, fCO 2, oxygen and Chlorophyll a (Chl a) were performed in the surface waters from Cape Town (South Africa) to Queen Maud Land (Antarctica) in the Atlantic sector of the Southern Ocean during the austral summer 1997/1998. From direct measurements of these parameters and from calculated fCO 2 the oceanic carbon dioxide system was studied and related to hydrological and biological parameters. fCO 2 was in general undersaturated relative to the atmosphere and showed a large variability with values ranging from 313 to 377 μatm with a mean value of 346±13 μatm. The undersaturation was more pronounced in areas associated with fronts where high Chl a and high pH in situ values were observed. Using shipboard wind speed data, estimates of the CO 2 flux were made along the transect and during three mesoscale surveys on the northward return transect in the area of the Spring Ice Edge (SIE), the Winter Ice Edge (WIE) and in the Antarctic Polar Front (APF). The undersaturation observed during the transect caused the ocean to act as a sink for CO 2 with a mean sea-air flux for the entire transect of -3±5 mmol m -2 d -1 with a large variability between -20 mmol m -2 d -1 (oceanic uptake) to 1.3 mmol m -2 d -1 (oceanic source). The lowest fCO 2 values (largest oceanic uptake of CO 2) were found at the southern boundary of the APF at 53°S, which coincided with a supersaturation in oxygen and high pH values. Oxygen concentrations were measured from 50°S to 63°S and varied between 324 and 359 μmol kg -1 with a mean value of 347±9 μmol kg -1. In general only small deviations from equilibrium oxygen saturation were observed (mean value=99±2%). However, in the SIE oxygen was clearly undersaturated, probably an effect of upwelling of oxygen poor deep water which had not yet been compensated for by biological production. Three weeks later, the ice edge had retreated in the SIE region and the Chl a concentration had increased three

  7. Effect of coagulant/flocculant dosage and pH to water recovery of black liquor wastewater in bioethanol production from oil palm empty fruit bunch using response surface methodology

    Science.gov (United States)

    Burhani, Dian; Winarni, Anissa; Sari, Ajeng Arum

    2017-01-01

    Coagulation and flocculation process was used to treat black liquor wastewater from alkali pretreatment of bioethanol production from oil palm empty fruit bunch. The optimization and the effect of pH, coagulant and flocculant dosage against decolorization, TSS reduction, final pH and sludge volume were investigated using Response Surface Methodology (RSM). Six combination were used, however, no combination gave good result to all four responses. Decolorization percentage of 99.69% was obtained by the combination of PAC and anionic polyacrylamide. The combination of alum and anionic polyacrylamide gave 91.12% TSS reduction. Final pH of 7.3 was resulted also from the combination of PAC and anionic polyacrylamide While, 50 ml sludge volume was generated from the combination of PAC and anionic polyacrylamide. From RSM with Central Composite Design (CCD) analysis, strong interaction between coagulant dosage and pH revealed to be the significant factor for black liquor wastewater treatment.

  8. Water on graphene surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Gordillo, M C [Departamento de Sistemas Fisicos, Quimicos y Naturales, Facultad de Ciencias Experimentales, Universidad Pablo de Olavide, Carretera de Utrera, km 1, E-41013 Sevilla (Spain); Marti, J, E-mail: cgorbar@upo.e, E-mail: jordi.marti@upc.ed [Departament de Fisica i Enginyeria Nuclear, Universitat Politecnica de Catalunya, B4-B5 Campus Nord, E-08034 Barcelona, Catalonia (Spain)

    2010-07-21

    In this paper, we summarize the main results obtained in our group about the behavior of water confined inside or close to different graphene surfaces by means of molecular dynamics simulations. These include the inside and outside of carbon nanotubes, and the confinement inside a slit pore or a single graphene sheet. We paid special attention to some thermodynamical (binding energies), structural (hydrogen-bond distributions) and dynamic (infrared spectra) properties, and their comparison to their bulk counterparts.

  9. The Dynamic Surface Tension of Water.

    Science.gov (United States)

    Hauner, Ines M; Deblais, Antoine; Beattie, James K; Kellay, Hamid; Bonn, Daniel

    2017-03-23

    The surface tension of water is an important parameter for many biological or industrial processes, and roughly a factor of 3 higher than that of nonpolar liquids such as oils, which is usually attributed to hydrogen bonding and dipolar interactions. Here we show by studying the formation of water drops that the surface tension of a freshly created water surface is even higher (∼90 mN m(-1)) than under equilibrium conditions (∼72 mN m(-1)) with a relaxation process occurring on a long time scale (∼1 ms). Dynamic adsorption effects of protons or hydroxides may be at the origin of this dynamic surface tension. However, changing the pH does not significantly change the dynamic surface tension. It also seems unlikely that hydrogen bonding or dipole orientation effects play any role at the relatively long time scale probed in the experiments.

  10. Estimating pH at the Air/Water Interface with a Confocal Fluorescence Microscope.

    Science.gov (United States)

    Yang, Haiya; Imanishi, Yasushi; Harata, Akira

    2015-01-01

    One way to determine the pH at the air/water interface with a confocal fluorescence microscope has been proposed. The relation between the pH at the air/water interface and that in a bulk solution has been formulated in connection with the adsorption equilibrium and the dissociation equilibrium of the dye adsorbed. Rhodamine B (RhB) is used as a surface-active fluorescent pH probe. The corrected fluorescence spectrum of RhB molecules at the air/water interface with the surface density of 1.0 nmol m(-2) level shows pH-dependent shifts representing an acid-base equilibrium. Two ways to determine the unknown acid-base equilibrium constant of RhB molecules at the air/water interface have been discussed. With surface-tension measurements, the adsorption properties, maximum surface density, and adsorption equilibrium constants were estimated for both cationic and zwitterionic forms of RhB molecules at the air/water interface.

  11. Aggregation behaviors of PEO-PPO-ph-PPO-PEO and PPO-PEO-ph-PEO-PPO at an air/water interface: experimental study and molecular dynamics simulation.

    Science.gov (United States)

    Gong, Houjian; Xu, Guiying; Liu, Teng; Xu, Long; Zhai, Xueru; Zhang, Jian; Lv, Xin

    2012-09-25

    The block polyethers PEO-PPO-ph-PPO-PEO (BPE) and PPO-PEO-ph-PEO-PPO (BEP) are synthesized by anionic polymerization using bisphenol A as initiator. Compared with Pluronic P123, the aggregation behaviors of BPE and BEP at an air/water interface are investigated by the surface tension and dilational viscoelasticity. The molecular construction can influence the efficiency and effectiveness of block polyethers in decreasing surface tension. BPE has the most efficient ability to decrease surface tension of water among the three block polyethers. The maximum surface excess concentration (Γ(max)) of BPE is larger than that of BEP or P123. Moreover, the dilational modulus of BPE is almost the same as that of P123, but much larger than that of BEP. The molecular dynamics simulation provides the conformational variations of block polyethers at the air/water interface.

  12. In-situ test methods for assessment of surface pH of corroding sewer pipes

    DEFF Research Database (Denmark)

    Nielsen, Asbjørn Haaning; Vollertsen, Jes

    A method for measuring the surface pH of corroding concrete was developed in the lab and tested in the field. The method is based on direct application of pH indicator solution on the corroding surfaces. Comparison against point measurements using a flat surface pH electrode (flatrode) confirmed...... the accuracy of the method. Blind testing of concrete specimens exposed to different acid concentrations demonstrated that it was possible to determine the surface pH within ±0.5 pH units in the pH range of one to five. The developed method provides a simple and reliable estimate on the extent of concrete...

  13. Ionic strength and pH as control parameters for spontaneous surface oscillations.

    Science.gov (United States)

    Kovalchuk, N M; Pimienta, V; Tadmouri, R; Miller, R; Vollhardt, D

    2012-05-01

    A system far from equilibrium, where the surfactant transfer from a small drop located in the aqueous bulk to the air-water interface results in spontaneous nonlinear oscillations of surface tension, is theoretically and experimentally considered. The oscillations in this system are the result of periodically arising and terminating Marangoni instability. The surfactant under consideration is octanoic acid, the dissociated form of which is much less surface-active than the protonated form. Numerical simulations show how the system behavior can be controlled by changes in pH and ionic strength of the aqueous phase. The results of numerical simulations are in good agreement with experimental data.

  14. Sustaining dry surfaces under water

    DEFF Research Database (Denmark)

    Jones, Paul R.; Hao, Xiuqing; Cruz-Chu, Eduardo R.

    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...

  15. Sustaining dry surfaces under water

    Science.gov (United States)

    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.

    2015-08-01

    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.

  16. Artificial Ground Water Recharge with Surface Water

    Science.gov (United States)

    Heviánková, Silvie; Marschalko, Marian; Chromíková, Jitka; Kyncl, Miroslav; Korabík, Michal

    2016-10-01

    With regard to the adverse manifestations of the recent climatic conditions, Europe as well as the world have been facing the problem of dry periods that reduce the possibility of drawing drinking water from the underground sources. The paper aims to describe artificial ground water recharge (infiltration) that may be used to restock underground sources with surface water from natural streams. Among many conditions, it aims to specify the boundary and operational conditions of the individual aspects of the artificial ground water recharge technology. The principle of artificial infiltration lies in the design of a technical system, by means of which it is possible to conduct surplus water from one place (in this case a natural stream) into another place (an infiltration basin in this case). This way, the water begins to infiltrate into the underground resources of drinking water, while the mixed water composition corresponds to the water parameters required for drinking water.

  17. Total Phosphorus in Surface Water

    Data.gov (United States)

    U.S. Environmental Protection Agency — Excess phosphorus in surface water can result in eutrophication. TOTALP is reported in kilograms/hectare/year. More information about these resources, including the...

  18. Total Nitrogen in Surface Water

    Data.gov (United States)

    U.S. Environmental Protection Agency — Excess nitrogen in surface water can result in eutrophication. TOTALN is reported in kilograms/hectare/year. More information about these resources, including the...

  19. Free Surface Water Tunnel (FSWT)

    Data.gov (United States)

    Federal Laboratory Consortium — Description: The Free Surface Water Tunnel consists of the intake plenum, the test section and the exit plenum. The intake plenum starts with a perforated pipe that...

  20. Muscle surface pH: measurement technique and responses to acidosis and alkalosis.

    Science.gov (United States)

    Kost, G J

    1982-01-01

    The technique of muscle surface pH measurement used clinically was refined for application in animal experimentation. Guidelines for electrode utilization were developed, and sources of error were investigated. In pentobarbital sodium-anesthetized rabbits, during steady-state conditions, the surface pH of the medial gastrocnemius [7.39 +/- 0.05 (SD)] was equal to that of the soleus, and both were lower than femoral venous outflow pH (7.42 +/- 0.04, P less than 0.001), which was lower than arterial pH (7.46 +/- 0.05, P less than 0.001). With acid-base infusions, the same relationship found during steady-state control conditions (arterial greater than venous outflow greater than muscle surface pH) was observed despite large fluctuations in blood pH. Only during forced hypoventilation, when CO2 transiently moved into muscle, did the relationship reverse. In all experiments, muscle surface pH followed venous outflow pH more closely than it followed arterial pH, the soleus more rapidly than the medial gastrocnemius. Results were consistent with the physiological characteristics of the two muscles and demonstrated that muscle surface pH reflects the local pH of the interstitial compartment under the site of electrode placement.

  1. Locally driven interannual variability of near-surface pH and ΩA in the Strait of Georgia

    Science.gov (United States)

    Moore-Maley, Ben L.; Allen, Susan E.; Ianson, Debby

    2016-03-01

    Declines in mean ocean pH and aragonite saturation state (ΩA) driven by anthropogenic CO2 emissions have raised concerns regarding the trends of pH and ΩA in estuaries. Low pH and ΩA can be harmful to a variety of marine organisms, especially those with calcium carbonate shells, and so may threaten the productive ecosystems and commercial fisheries found in many estuarine environments. The Strait of Georgia is a large, temperate, productive estuarine system with numerous wild and aquaculture shellfish and finfish populations. We determine the seasonality and variability of near-surface pH and ΩA in the Strait using a one-dimensional, biophysical, mixing layer model. We further evaluate the sensitivity of these quantities to local wind, freshwater, and cloud forcing by running the model over a wide range of scenarios using 12 years of observations. Near-surface pH and ΩA demonstrate strong seasonal cycles characterized by low pH, aragonite-undersaturated waters in winter and high pH, aragonite-supersaturated waters in summer. The aragonite saturation horizon generally lies at ˜20 m depth except in winter and during strong Fraser River freshets when it shoals to the surface. Periods of strong interannual variability in pH and aragonite saturation horizon depth arise in spring and summer. We determine that at different times of year, each of wind speed, freshwater flux, and cloud fraction are the dominant drivers of this variability. These results establish the mechanisms behind the emerging observations of highly variable near-surface carbonate chemistry in the Strait.

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

    Science.gov (United States)

    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

  3. Solubility of water in lunar basalt at low pH2O

    Science.gov (United States)

    Newcombe, M. E.; Brett, A.; Beckett, J. R.; Baker, M. B.; Newman, S.; Guan, Y.; Eiler, J. M.; Stolper, E. M.

    2017-03-01

    We report the solubility of water in Apollo 15 basaltic "Yellow Glass" and an iron-free basaltic analog composition at 1 atm and 1350 °C. We equilibrated melts in a 1-atm furnace with flowing H2/CO2 gas mixtures that spanned ∼8 orders of magnitude in fO2 (from three orders of magnitude more reducing than the iron-wüstite buffer, IW-3.0, to IW+4.8) and ∼4 orders of magnitude in pH2/pH2O (from 0.003 to 24). Based on Fourier transform infrared spectroscopy (FTIR), our quenched experimental glasses contain 69-425 ppm total water (by weight). Our results demonstrate that under the conditions of our experiments: (1) hydroxyl is the only H-bearing species detected by FTIR; (2) the solubility of water is proportional to the square root of pH2O in the furnace atmosphere and is independent of fO2 and pH2/pH2O; (3) the solubility of water is very similar in both melt compositions; (4) the concentration of H2 in our iron-free experiments is ppm, even at oxygen fugacities as low as IW-2.3 and pH2/pH2O as high as 11; (5) Secondary ion mass spectrometry (SIMS) analyses of water in iron-rich glasses equilibrated under variable fO2 conditions may be strongly influenced by matrix effects, even when the concentration of water in the glasses is low; and (6) Our results can be used to constrain the entrapment pressure of lunar melt inclusions and the partial pressures of water and molecular hydrogen in the carrier gas of the lunar pyroclastic glass beads. We find that the most water-rich melt inclusion of Hauri et al. (2011) would be in equilibrium with a vapor with pH2O ∼ 3 bar and pH2 ∼ 8 bar. We constrain the partial pressures of water and molecular hydrogen in the carrier gas of the lunar pyroclastic glass beads to be 0.0005 bar and 0.0011 bar respectively. We calculate that batch degassing of lunar magmas containing initial volatile contents of 1200 ppm H2O (dissolved primarily as hydroxyl) and 4-64 ppm C would produce enough vapor to reach the critical vapor volume

  4. Predicted pH at the domestic and public supply drinking water depths, Central Valley, California

    Science.gov (United States)

    Rosecrans, Celia Z.; Nolan, Bernard T.; Gronberg, Jo Ann M.

    2017-03-08

    This scientific investigations map is a product of the U.S. Geological Survey (USGS) National Water-Quality Assessment (NAWQA) project modeling and mapping team. The prediction grids depicted in this map are of continuous pH and are intended to provide an understanding of groundwater-quality conditions at the domestic and public supply drinking water zones in the groundwater of the Central Valley of California. The chemical quality of groundwater and the fate of many contaminants is often influenced by pH in all aquifers. These grids are of interest to water-resource managers, water-quality researchers, and groundwater modelers concerned with the occurrence of natural and anthropogenic contaminants related to pH. In this work, the median well depth categorized as domestic supply was 30 meters below land surface, and the median well depth categorized as public supply is 100 meters below land surface. Prediction grids were created using prediction modeling methods, specifically boosted regression trees (BRT) with a Gaussian error distribution within a statistical learning framework within the computing framework of R (http://www.r-project.org/). The statistical learning framework seeks to maximize the predictive performance of machine learning methods through model tuning by cross validation. The response variable was measured pH from 1,337 wells and was compiled from two sources: USGS National Water Information System (NWIS) database (all data are publicly available from the USGS: http://waterdata.usgs.gov/ca/nwis/nwis) and the California State Water Resources Control Board Division of Drinking Water (SWRCB-DDW) database (water quality data are publicly available from the SWRCB: http://www.waterboards.ca.gov/gama/geotracker_gama.shtml). Only wells with measured pH and well depth data were selected, and for wells with multiple records, only the most recent sample in the period 1993–2014 was used. A total of 1,003 wells (training dataset) were used to train the BRT

  5. Effects of different saliva pH on hybrid composite resin surface roughness

    Directory of Open Access Journals (Sweden)

    Nirawati Pribadi

    2011-06-01

    Full Text Available Background: Currently, hybrid composite resin is the mostly used filling material to restore esthetic and function. During function, this material is in contact with various pH from food consumption, which is acidic and alkali which may effect the physical properties of composite resin, including surface roughness. Purpose: The research was conducted to determine the effect of pH in saliva on surface roughness of hybrid composite resin. Methods: This research used artificial saliva and composite resin samples divided into 3 groups based on different pH of immersion (pH 4, pH 7 and pH 10 for 30 days. Results: There were significant differences (p > 0.05 among those three treatment groups of hybrid composites soaked in artificial saliva with different pH for 30 days. And, with LSD test it is also known that there were significant differences between the artificial saliva with pH 4 and pH 7, whereas there was no significant difference between pH 4 and pH 10 and between pH 7 and pH 10. Conclusion: It can concluded that the changes of salivary pH affect the surface roughness of the hybrid composite resin. Acidic pH has increase the surface roughness of hybrid composite resin, whereas alkaline pH has no effects on the surface roughness of hybrid composite resin.Latar belakang: Saat ini tumpatan komposit merupakan bahan tumpatan yang paling sering digunakan untuk memperbaiki estetik dan fungsi. Dalam rongga mulut, bahan ini kontak dengan berbagai macam pH dari konsumsi makanan, baik asam maupun basa yang dapat mempengaruhi perubahan sifat fisik resin komposit, diantaranya yaitu kekasaran permukaan. Tujuan: Penelitian ini dilakukan untuk mengetahui tentang efek pH saliva terhadap kekasaran permukaan tumpatan resin komposit hybrid. Metode: Penelitian ini menggunakan saliva buatan yang dibagi dalam 3 kelompok sampel yaitu masing-masing dengan perendaman pH yang berbeda (pH 4, pH 7 dan pH 10selama 30 hari. Hasil: Terdapat perbedaan yang bermakna (p > 0

  6. Recovery from acidification in European surface waters

    Directory of Open Access Journals (Sweden)

    C. D. Evans

    2001-01-01

    Full Text Available Water quality data for 56 long-term monitoring sites in eight European countries are used to assess freshwater responses to reductions in acid deposition at a large spatial scale. In a consistent analysis of trends from 1980 onwards, the majority of surface waters (38 of 56 showed significant (p ≤0.05 decreasing trends in pollution-derived sulphate. Only two sites showed a significant increase. Nitrate, on the other hand, had a much weaker and more varied pattern, with no significant trend at 35 of 56 sites, decreases at some sites in Scandinavia and Central Europe, and increases at some sites in Italy and the UK. The general reduction in surface water acid anion concentrations has led to increases in acid neutralising capacity (significant at 27 of 56 sites but has also been offset in part by decreases in base cations, particularly calcium (significant at 26 of 56 sites, indicating that much of the improvement in runoff quality to date has been the result of decreasing ionic strength. Increases in acid neutralising capacity have been accompanied by increases in pH and decreases in aluminium, although fewer trends were significant (pH 19 of 56, aluminium 13 of 53. Increases in pH appear to have been limited in some areas by rising concentrations of organic acids. Within a general trend towards recovery, some inter-regional variation is evident, with recovery strongest in the Czech Republic and Slovakia, moderate in Scandinavia and the United Kingdom, and apparently weakest in Germany. Keywords: acidification, recovery, European trends, sulphate, nitrate, acid neutralising capacity

  7. Groundwater–Surface Water Exchange

    DEFF Research Database (Denmark)

    Karan, Sachin

    The exchange of groundwater-surface water has been invetigated in the western part of Denmark. Holtum AA provides the framework for all the performed investigations. Several methods are used, primarily eld based measurements ombined with numerical models to achieve insight to the governing...... processes of interaction between groundwater and surface water. By using heat as a tracer it has been possible to use temperature directly as calibrationtargets in a groundwater and heat transport model. Thus, it is possible to use heat investigate the change in groundwater discharge in dynamic conditions...... by using simple temperature devices along a stream to delineate the areas of interest in regard to GW{SW exchange. Thus, at several locations in a stream a temperature data logger was placed in the water column and right at the streambed-water interface. By looking at the correlation of streambed...

  8. Groundwater–Surface Water Exchange

    DEFF Research Database (Denmark)

    Karan, Sachin

    The exchange of groundwater-surface water has been invetigated in the western part of Denmark. Holtum AA provides the framework for all the performed investigations. Several methods are used, primarily eld based measurements ombined with numerical models to achieve insight to the governing...... processes of interaction between groundwater and surface water. By using heat as a tracer it has been possible to use temperature directly as calibrationtargets in a groundwater and heat transport model. Thus, it is possible to use heat investigate the change in groundwater discharge in dynamic conditions...... by using simple temperature devices along a stream to delineate the areas of interest in regard to GW{SW exchange. Thus, at several locations in a stream a temperature data logger was placed in the water column and right at the streambed-water interface. By looking at the correlation of streambed...

  9. Effects of pH on rheological characteristics and stability of petroleum coke water slurry

    Directory of Open Access Journals (Sweden)

    Fu-Yan Gao

    2016-10-01

    Full Text Available Abstract In this study, the effects of pH on slurrying properties of petroleum coke water slurry (PCWS were investigated. The slurrying concentration, rheological characteristics and stability of PCWS were studied with four different types of additives at pH varying from 5 to 11. The results showed that the slurrying concentration, rheological characteristics and stability of PCWS all increased at first and then decreased with increasing pH from 5 to 11, and a pH of around 9 was found to be the most favorable acid–alkali environment to all these three slurrying properties. It was also indicated that only in a moderate alkaline environment can the additives be active enough to react with particle surfaces sufficiently to obtain good slurrying concentration and form a stable three-dimensional network structure, which can support strong pseudoplastic characteristics and good stability. An acid environment was a very unfavorable factor to the slurrying properties of PCWS.

  10. Surface activity evaluation of an arabinose ester as water/oil demulsifier at severe conditions of temperature, salinity and pH; Avaliacao da atividade superficial de um ester de arabinose, como desemulsificante agua/oleo, em condicoes severas de temperatura, salinidade e pH

    Energy Technology Data Exchange (ETDEWEB)

    Borges, Mauricio Rodrigues; Garcia, Rosangela Balaban; Santos, Jaciara Alves dos; Vieira, Mariane; Silva, Luciana Carvalho; Campos, Viviane de Oliveira; Silva, Rayane Araujo da; Santos, Telma Pitanga dos [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)

    2008-07-01

    This work had for objective to compare the superficial properties of an arabinose ester, no-ionic, nontoxic, biodegradable, with two commercial products: the first one based on sodium dodecyl sulfate and the second one based on poly-oxy alkylene phenol formaldehyde. The arabinose ester was synthesized on the Petroleum Research Laboratory - UFRN, through enzymatic catalysis by protease from Bacillus subtilis, using arabinose and vegetable oil, in organic medium. In previous work [1], this sugar ester was evaluated as a possible water/oil demulsifier and the results were compared with the results of the commercial product based on poly-oxy alkylene phenol formaldehyde, showing that, for certain reaction conditions, the sugar ester presented better acting (71%) that the commercial product (33%) as demulsifier. In this work, the stability of this arabinose ester was evaluated in severe conditions of temperature, salinity and pH, through superficial tests in a tensiometer, using Wilhelmy plate method and the results were compared with the results obtained for two commercial products above mentioned. (author)

  11. Molecular layer deposition of APTES on silicon nanowire biosensors: Surface characterization, stability and pH response

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Yuchen [Department of Electrical Engineering, University of Texas at Dallas, Richardson, TX 75080 (United States); Huang, Jie [Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, TX 75080 (United States); Zang, Pengyuan [Department of Electrical Engineering, University of Texas at Dallas, Richardson, TX 75080 (United States); Kim, Jiyoung [Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, TX 75080 (United States); Hu, Walter, E-mail: walter.hu@utdallas.edu [Department of Electrical Engineering, University of Texas at Dallas, Richardson, TX 75080 (United States)

    2014-12-15

    Graphical abstract: - Abstract: We report the use of molecular layer deposition (MLD) for depositing 3-aminopropyltriethoxysilane (APTES) on a silicon dioxide surface. The APTES monolayer was characterized using spectroscopic ellipsometry, contact angle goniometry, and atomic force microscopy. Effects of reaction time of repeating pulses and simultaneous feeding of water vapor with APTES were tested. The results indicate that the synergistic effects of water vapor and reaction time are significant for the formation of a stable monolayer. Additionally, increasing the number of repeating pulses improved the APTES surface coverage but led to saturation after 10 pulses. In comparing MLD with solution-phase deposition, the APTES surface coverage and the surface quality were nearly equivalent. The hydrolytic stability of the resulting films was also studied. The results confirmed that the hydrolysis process was necessary for MLD to obtain stable surface chemistry. Furthermore, we compared the pH sensing results of Si nanowire field effect transistors (Si NWFETs) modified by both the MLD and solution methods. The highly repeatable pH sensing results reflected the stability of APTES monolayers. The results also showed an improved pH response of the sensor prepared by MLD compared to the one prepared by the solution treatment, which indicated higher surface coverage of APTES.

  12. Molecular layer deposition of APTES on silicon nanowire biosensors: Surface characterization, stability and pH response

    Science.gov (United States)

    Liang, Yuchen; Huang, Jie; Zang, Pengyuan; Kim, Jiyoung; Hu, Walter

    2014-12-01

    We report the use of molecular layer deposition (MLD) for depositing 3-aminopropyltriethoxysilane (APTES) on a silicon dioxide surface. The APTES monolayer was characterized using spectroscopic ellipsometry, contact angle goniometry, and atomic force microscopy. Effects of reaction time of repeating pulses and simultaneous feeding of water vapor with APTES were tested. The results indicate that the synergistic effects of water vapor and reaction time are significant for the formation of a stable monolayer. Additionally, increasing the number of repeating pulses improved the APTES surface coverage but led to saturation after 10 pulses. In comparing MLD with solution-phase deposition, the APTES surface coverage and the surface quality were nearly equivalent. The hydrolytic stability of the resulting films was also studied. The results confirmed that the hydrolysis process was necessary for MLD to obtain stable surface chemistry. Furthermore, we compared the pH sensing results of Si nanowire field effect transistors (Si NWFETs) modified by both the MLD and solution methods. The highly repeatable pH sensing results reflected the stability of APTES monolayers. The results also showed an improved pH response of the sensor prepared by MLD compared to the one prepared by the solution treatment, which indicated higher surface coverage of APTES.

  13. Influence of pH on Chemical Forms of Phosphate Adfsorbed on Gothite Surfaces

    Institute of Scientific and Technical Information of China (English)

    LIUFAN; WANGDIAN-FEN; 等

    1995-01-01

    Chemical forms of the phosphate adsorbed on goethite surfaces and characteristics of the coordinate groups which exchange with P on goethite surfaces in solutions with different pll values were investigated.Results showed that the chemical forms of P on goethite surfaces changed from the dominance of monodentate corrdination to that of bidentate one with increasing pH of the solution.By influencing types of phosphate ions in solutions,pH affected the chemical forms of P on goethite surfaces,The amount of OH- displaced by phosphae on goethite surfaces was the most at pH 7.0,the second at pH 9.0,and the least at pH 4.5.

  14. Partial oxidation of Step-Bound Water Leads to Anomalous pH Effects on Metal Electrode Step-Edges

    CERN Document Server

    Schwarz, Kathleen; Yan, Yushan; Sundararaman, Ravishankar

    2016-01-01

    The design of better heterogeneous catalysts for applications such as fuel cells and electrolyzers requires a mechanistic understanding of electrocatalytic reactions and the dependence of their activity on operating conditions such as pH. A satisfactory explanation for the unexpected pH dependence of electrochemical properties of platinum surfaces has so far remained elusive, with previous explanations resorting to complex co-adsorption of multiple species and resulting in limited predictive power. This knowledge gap suggests that the fundamental properties of these catalysts are not yet understood, limiting systematic improvement. Here, we analyze the change in charge and free energies upon adsorption using density-functional theory (DFT) to establish that water adsorbs on platinum step edges across a wide voltage range, including the double-layer region, with a loss of approximately 0.2 electrons upon adsorption. We show how the change in net surface charge due to this water explains the anomalous pH variat...

  15. Mobile surface water filtration system

    Directory of Open Access Journals (Sweden)

    Aashish Vatsyayan

    2012-09-01

    Full Text Available To design a mobile system for surface water filtrationMethodology: the filtration of surface impurities begins with their retraction to concentrated thickness using non ionising surfactants, then isolation using surface tension property and sedimentation of impurities in process chamber using electrocoagulation. Result:following studies done to determine the rate of spreading of crude oil on water a method for retraction of spread crude oil to concentrated volumes is developed involving addition of non -ionising surfactants in contrast to use of dispersants. Electrocoagulation process involves multiple processes taking place to lead to depositionof impurities such as oil, grease, metals. Studies of experiments conducted reveals parameters necessary for design of electrocoagulation process chamber though a holistic approach towards system designing is still required. Propeller theory is used in determining the required design of propeller and the desired thrust, the overall structure will finally contribute in deciding the choice of propeller.

  16. The pH Value of Fungicide, Insecticide and Mineral Fertilizer Mixtures Depending on Water Quality

    Directory of Open Access Journals (Sweden)

    Dušanka Inđić

    2008-01-01

    Full Text Available The paper deals with the effect of water quality on the pH value of fungicides, insecticides, mineral fertilizers and their mixtures. The fungicides propineb (Antracol WP-70 and mancozeb (Dithane M-70, insecticides pirimiphos-methyl (Actellic-50 and imidacloprid(Confidor 200-SL, several fertilizers (Ferticare I, Ferticare II, Ferticare III and Wuxal Super and their mixtures were analyzed for pH value under laboratory conditions using a potentiometric pH meter. Measurements were made directly after preparation or mixing with tap and well water and 24 hours later. Tap water exhibited a neutral reaction. A slightly alkaline reaction of well water was mostlikely due to high ammonium content. The suspensions of Antracol WP-70 exhibited slightly alkaline reactions with both water types during 24 hours. The spray liquids of Dithane M-70 mixed with tap or well water had neutral reaction after preparation and slightly alkaline reaction after 24 hours. The emulsions of Actellic-50 showed neutral reaction with both water types, followed by a pH increase in tap water after 24 hours. The solutions of Confidor200-SL had a slightly alkaline reaction after mixing and the pH value increased with both water types after 24 hours. It is therefore recommended to apply these insecticides directly after preparation. Mineral fertilizers considerably reduced pH values of the fungicide and insecticide components in double and triple mixtures, especially Ferticare nutrients which had a moderately acid reaction. Wuxal Super had a neutral reaction with both water types.The mixtures with well water increased pH values, which indicates that water pH does affect the pH value of the mixture. Both individual fertilizers and all mixtures (double and triple with Ferticare had pH values between 2.4 and 6, which allows their active liquids to be stored for 12 to 24 hours. The suspensions (Antracol WP-70, double and triple mixtures, emulsions (Actellic-50 and Actellic-50+Wuxal Super

  17. Effect of low pH on surface rehardening efficacy of high concentration fluoride treatments on non-cavitated lesions.

    Science.gov (United States)

    González-Cabezas, C; Jiang, H; Fontana, M; Eckert, G

    2012-06-01

    Professionally applied acidulated phosphate fluoride has been shown to reduce caries incidence. However, it has been suggested that its efficacy might be reduced in advanced non-cavitated lesions. This study aimed to compare the surface rehardening and fluoride uptake effect of 2%-NaF solutions at different pH on non-cavitated caries-like lesions with two different levels of demineralization. Human enamel specimens were demineralized to create early and advanced non-cavitated lesions. Specimens for each type of lesion were divided into 3 groups, treated for four minutes with either 2%-NaF pH 3.5, 2%-NaF at pH 7.0, or neutral deionized water, and exposed to a pH cycling remineralization/demineralization model for five days. An additional treatment was then done as described above followed by five more days of cycling (total of 2 treatments, ten-day pH cycling). Specimens were analyzed for surface microhardness change and fluoride uptake. It was found that for both types of lesions, acidic pH fluoride treatment was significantly (pfluoride uptake. Furthermore, the low pH vs neutral pH difference in rehardening was significantly larger in the less demineralized lesions (p=0.0001). Water treatment resulted in no rehardening or fluoride uptake. Results from this study suggest that high concentration fluoride treatments at acidic pH are more effective in rehardening the surface of non-cavitated caries lesions and promoting fluoride uptake than those at neutral pH. This effect appears to be greater in less demineralized lesions when compared to more advanced ones. The results of this investigation suggest that when no other attenuating circumstances are present (e.g., the possibility of damaging tooth-coloured restorations), high concentration fluoride treatments for high risk individuals might be more efficacious using products at low pH. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Immobilized fluorescent dyes for sensitive pH measurements on enamel surfaces with fiber optics

    Science.gov (United States)

    Rumphorst, A.; Seeger, Stefan; Duschner, H.

    1996-01-01

    Information on the pH directly on surfaces of dental enamel is an important aspect in research on tooth decay. As an alternative to pH-electrodes our approach to the problem is the optical determination of pH by pH sensitive fluorescent dyes immobilized to tooth surfaces. In this study a model for measuring pH either on aminated cellulose substrates or on enamel (in vitro) with a fluorescein type dye is presented. The experimental realization is a fiber optic sensor with a nitrogen-pumped dye laser system and photodiode for the detection of the emitted fluorescence light. The surface pH values in the range between 4 and 7 were derived from the ratios of the excitation bands at 490 nm and 460 nm.

  19. Microbial sulfate reduction and metal attenuation in pH 4 acid mine water

    Directory of Open Access Journals (Sweden)

    Alpers Charles N

    2007-10-01

    Full Text Available Abstract Sediments recovered from the flooded mine workings of the Penn Mine, a Cu-Zn mine abandoned since the early 1960s, were cultured for anaerobic bacteria over a range of pH (4.0 to 7.5. The molecular biology of sediments and cultures was studied to determine whether sulfate-reducing bacteria (SRB were active in moderately acidic conditions present in the underground mine workings. Here we document multiple, independent analyses and show evidence that sulfate reduction and associated metal attenuation are occurring in the pH-4 mine environment. Water-chemistry analyses of the mine water reveal: (1 preferential complexation and precipitation by H2S of Cu and Cd, relative to Zn; (2 stable isotope ratios of 34S/32S and 18O/16O in dissolved SO4 that are 2–3 ‰ heavier in the mine water, relative to those in surface waters; (3 reduction/oxidation conditions and dissolved gas concentrations consistent with conditions to support anaerobic processes such as sulfate reduction. Scanning electron microscope (SEM analyses of sediment show 1.5-micrometer, spherical ZnS precipitates. Phospholipid fatty acid (PLFA and denaturing gradient gel electrophoresis (DGGE analyses of Penn Mine sediment show a high biomass level with a moderately diverse community structure composed primarily of iron- and sulfate-reducing bacteria. Cultures of sediment from the mine produced dissolved sulfide at pH values near 7 and near 4, forming precipitates of either iron sulfide or elemental sulfur. DGGE coupled with sequence and phylogenetic analysis of 16S rDNA gene segments showed populations of Desulfosporosinus and Desulfitobacterium in Penn Mine sediment and laboratory cultures.

  20. Microbial sulfate reduction and metal attenuation in pH 4 acid mine water

    Science.gov (United States)

    Church, C.D.; Wilkin, R.T.; Alpers, C.N.; Rye, R.O.; Blaine, R.B.

    2007-01-01

    Sediments recovered from the flooded mine workings of the Penn Mine, a Cu-Zn mine abandoned since the early 1960s, were cultured for anaerobic bacteria over a range of pH (4.0 to 7.5). The molecular biology of sediments and cultures was studied to determine whether sulfate-reducing bacteria (SRB) were active in moderately acidic conditions present in the underground mine workings. Here we document multiple, independent analyses and show evidence that sulfate reduction and associated metal attenuation are occurring in the pH-4 mine environment. Water-chemistry analyses of the mine water reveal: (1) preferential complexation and precipitation by H2S of Cu and Cd, relative to Zn; (2) stable isotope ratios of 34S/32S and 18O/16O in dissolved SO4 that are 2-3 ??? heavier in the mine water, relative to those in surface waters; (3) reduction/oxidation conditions and dissolved gas concentrations consistent with conditions to support anaerobic processes such as sulfate reduction. Scanning electron microscope (SEM) analyses of sediment show 1.5-micrometer, spherical ZnS precipitates. Phospholipid fatty acid (PLFA) and denaturing gradient gel electrophoresis (DGGE) analyses of Penn Mine sediment show a high biomass level with a moderately diverse community structure composed primarily of iron- and sulfate-reducing bacteria. Cultures of sediment from the mine produced dissolved sulfide at pH values near 7 and near 4, forming precipitates of either iron sulfide or elemental sulfur. DGGE coupled with sequence and phylogenetic analysis of 16S rDNA gene segments showed populations of Desulfosporosinus and Desulfitobacterium in Penn Mine sediment and laboratory cultures. ?? 2007 Church et al; licensee BioMed Central Ltd.

  1. Is Your Drinking Water Acidic? A Comparison of the Varied pH of Popular Bottled Waters

    National Research Council Canada - National Science Library

    Wright, Kellie F

    2015-01-01

    .... However, water is not typically categorized as acidic. The purpose of this in-vitro study was to investigate the pH levels of several popular brands of bottled water and compare them to various other acidic beverages...

  2. Is Your Drinking Water Acidic? A Comparison of the Varied pH of Popular Bottled Waters.

    Science.gov (United States)

    Wright, Kellie F

    2015-06-01

    Dental professionals continually educate patients on the dangers of consuming acidic foods and beverages due to their potential to contribute to dental erosion and tooth decay. Excess acid in the diet can also lead to acidosis, which causes negative systemic side effects. However, water is not typically categorized as acidic. The purpose of this in-vitro study was to investigate the pH levels of several popular brands of bottled water and compare them to various other acidic beverages. Two different brands of marketed alkaline water (with a pH of 8.8 or higher) were also studied, tested for acidity and described. A pilot in-vitro study was conducted to determine the pH levels of a convenience sample of popular brands of bottled water, tap water and other known acidic beverages in comparison with the pH values reported on the respective manufacturers' website. Each beverage was tested in a laboratory using a calibrated Corning pH meter model 240, and waters were compared to the corresponding company's testified pH value. Waters were also compared and contrasted based on their process of purification. The data was then compiled and analyzed descriptively. The pH values for the tested beverages and bottled waters were found to be predominantly acidic. Ten out of the 14 beverages tested were acidic (pHwaters were neutral (pH=7) and 2 bottled waters were alkaline (pH>7). The majority of waters tested had a more acidic pH when tested in the lab than the value listed in their water quality reports. It is beneficial for the health care provider to be aware of the potential acidity of popular bottled drinking waters and educate patients accordingly. Copyright © 2015 The American Dental Hygienists’ Association.

  3. Distribution of total alkalinity and pH in the Ross Sea (Antarctica waters during austral summer 2008

    Directory of Open Access Journals (Sweden)

    Paola Rivaro

    2014-10-01

    Full Text Available Measurements of total alkalinity (AT and pH were made in the Ross Sea in January–February 2008 in order to characterize the carbonate system in the Ross Sea and to evaluate the variability associated with different water masses. The main water masses of the Ross Sea, Antarctic Surface Water, High Salinity Shelf Water (HSSW, Deep Ice Shelf Water, Circumpolar Deep Water (CDW and Antarctic Bottom Water, were identified on the basis of the physical and chemical data. In particular, the AT ranged between 2275 and 2374 µmol kg−1 with the lowest values in the surface waters (2275–2346 µmol kg−1, where the influence of the sea-ice melting and of the variability of the physical properties was significant. In the deep layers of the water column, the AT maxima were measured in correspondence to the preferential pathways of the spreading HSSW. The pH had variable values in the surface layer (7.890–8.033 with the highest values in Terra Nova Bay and Ross Sea polynyas. A low pH (7.969±0.025 traced the intrusion of the CDW in the Ross Sea shelf area. All samples revealed waters that were oversaturated with respect to both calcite and aragonite, but near corrosive levels of aragonite saturation state (Ω ca. 1.1–1.2 were associated with the entrainment of CDW over the slope. Aragonite undersaturation is of particular concern for the zooplankton species comprising to calcifying organisms such as pteropods. The partial pressure of CO2 at the sea surface was undersaturated with respect to the atmospheric value, particularly in Terra Nova Bay and the Ross Sea polynyas, but a large variability in the sea–air CO2 fluxes was observed associated with different responses in the strength of the biological and physical processes.

  4. Cadmium triggers Elodea canadensis to change the surrounding water pH and thereby Cd uptake.

    Science.gov (United States)

    Javed, M Tariq; Greger, Maria

    2011-01-01

    This study was aimed to investigate the influence of Elodea canadensis shoots on surrounding water pH in the presence of cadmium and the effect of plant-induced pH on cadmium uptake. The pH change in the surrounding nutrient solution and Cd uptake by Elodea shoots were investigated after cultivation of various plant densities (1, 3, 6 plants per 500 ml) in hydroponics at a starting pH of 4.0 and in the presence of different concentrations of cadmium (0, 0.1, 0.5 microM). Cadmium uptake was also investigated at different constant pH (4.0, 4.5, 5.5 and 6.5). To investigate if the pH change arose from photosynthetic activities, plants were grown under light, darkness or in the presence of a photosynthetic inhibitor, 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), and 0.5 microM cadmium in the solution. Elodea had an ability to increase the surrounding water pH, when the initial pH was low, which resulted in increased accumulation of Cd. The higher the plant density, the more pronounced was the pH change. The pH increase was not due to the photosynthetic activity since the pH rise was more pronounced under darkness and in the presence of DCMU. The pH increase by Elodea was triggered by cadmium.

  5. Nonlinear friction characteristics between silica surfaces in high pH solution.

    Science.gov (United States)

    Taran, Elena; Kanda, Yoichi; Vakarelski, Ivan U; Higashitani, Ko

    2007-03-15

    Molecular-scale characteristics of friction forces between silica particles and silica wafers in aqueous solutions of the normal (pH 5.6) and high pH (pH 10.6) are investigated, using the lateral force measuring procedure of the atomic force microscope (AFM). Various significant differences of friction characteristics between solutions of normal and high pH's are found. In the case of solutions of normal pH, the friction force increases linearly with increasing loading force, as the Amonton's law for solid bodies indicates. However, in the case of high pH solutions, the increasing rate with the loading force is considerably reduced in the low loading region, but the value increases abruptly above a critical loading force to overcome the magnitude of friction force of normal pH above the region of very high loading. It is very interesting to know that this nonlinear force curve at high pH is independent of the atomic-scale roughness of surfaces, although the magnitude of friction is greatly influenced by the roughness in the case of normal pH. The reason why the friction at high pH is independent of the surface roughness is postulated to be due to the hairy-like layer formed on the silica surface. The existence of hairy-like layers at high pH is proven directly by the dynamic method of normal force measurements with AFM and the thickness is estimated to be at least ca. 1.3 nm.

  6. Negative pH and extremely acidic mine waters from Iron Mountain, California

    Science.gov (United States)

    Nordstrom, D.K.; Alpers, C.N.; Ptacek, C.J.; Blowes, D.W.

    2000-01-01

    Extremely acidic mine waters with pH values as low as -3.6, total dissolved metal concentrations as high as 200 g/L, and sulfate concentrations as high as 760 g/L, have been encountered underground in the Richmond Mine at Iron Mountain, CA. These are the most acidic waters known. The pH measurements were obtained by using the Pitzer method to define pH for calibration of glass membrane electrodes. The calibration of pH below 0.5 with glass membrane electrodes becomes strongly nonlinear but is reproducible to a pH as low as -4. Numerous efflorescent minerals were found forming from these acid waters. These extreme acid waters were formed primarily by pyrite oxidation and concentration by evaporation with minor effects from aqueous ferrous iron oxidation and efflorescent mineral formation.

  7. Fabrication of pH sensitive nanovalves using smart surface coated nanopores

    Science.gov (United States)

    Nieto-Soto, A. M.; Diaz-Maldonado, D. K.; Rios Angarita, F. A.

    2017-01-01

    A pH sensitive nanovalve was fabricated using different smart surfaces covalently attached to an anodized aluminium oxide membrane (AAO). The smart surfaces were synthesized using a mixture of aliphatic and aminated silanes. Effect on the contact angle of the aliphatic silane chain length was evaluated. The smart surface, in conjunction with a nanoporous membrane, allowed the formation of a hydrophobic plug which controlled the transport of the molecule safranine depending on the pH of the solution. It was demonstrated that mixtures of butyl and methyl-trimethoxysilane with aminopropyl-trimethoxysilane were able to perform as effective nanovalves creating a plug that remained closed at pH>7 and opened up at pH<5.

  8. The pH of water from various sources: an overview for recommendation for patients with atopic dermatitis.

    Science.gov (United States)

    Kulthanan, Kanokvalai; Nuchkull, Piyavadee; Varothai, Supenya

    2013-07-01

    Patients with atopic dermatitis (AD) have increased susceptibility to irritants. Some patients have questions about types of water for bathing or skin cleansing. We studied the pH of water from various sources to give an overview for physicians to recommend patients with AD. Water from various sources was collected for measurement of the pH using a pH meter and pH-indicator strips. Bottled drinking still water had pH between 6.9 and 7.5 while the sparkling type had pH between 4.9 and 5.5. Water derived from home water filters had an approximate pH of 7.5 as same as tap water. Swimming pool water had had pH between 7.2 and 7.5 while seawater had a pH of 8. Normal saline and distilled water had pH of 5.4 and 5.7, respectively. Facial mineral water had pH between 7.5 and 8, while facial makeup removing water had an acidic pH. Normal saline, distilled water, bottled sparkling water and facial makeup removing water had similar pH to that of normal skin of normal people. However, other factors including benefits of mineral substances in the water in terms of bacteriostatic and anti-inflammation should be considered in the selection of cleansing water.

  9. The effect of pH modification on wetting kinetics of a naturally water repellent coniferous soil

    Science.gov (United States)

    Amer, Ahmad; Diehl, Dörte; Schaumann, Gabriele

    2017-04-01

    The interfacial dynamics of soil-water interactions are significantly affected by the hydrophobic properties of organic matter. The underlying mechanisms responsible for the development of soil water repellency (SWR) are still under discussion. Various environmental factors control the appearance and degree of SWR. The wetting of soil greatly depends on the physicochemical characteristics of soil surfaces which in turn depends on pH. In this contribution, we propose a mechanism for the change in SWR that is observed upon the artificial change in soil pH. Wetting kinetics were studied by the time dependent sessile drop measurements (TISED) of the contact angle, the work of spreading and the drop base diameter as time elapsed under controlled relative humidity. Modification of pH strongly affected the wetting kinetics, suggesting maximum wetting resistance at the control pH (3.60) and with decreased wetting resistance as pH was changed in either direction. The enhancement of the wetting kinetics by artificial modification of soil pH can be attributed to the chemical modification in organic materials coating soil particles based on the magnitude of spreading activation energy and the hydrophilic/hydrophobic moieties ratio of treated soil samples measured by (XPS & MIR spectroscopy). On the basis of our current state of knowledge, we propose that acid and base catalyzed hydrolysis-condensation reactions as dominant processes responsible for the chemical nature of SWR.

  10. Imines that React with Phenols in Water over a Wide pH Range

    Science.gov (United States)

    Minakawa, Maki; Guo, Hai-Ming

    2009-01-01

    Cyclic imine derivatives that react with phenols, including tyrosine residues of peptides, have been developed. Reactions of the imines with phenols proceeded in water over a wide pH range (pH 2-10) at room temperature to 37 °C and afforded Mannich products without the need of additional catalysts. PMID:18844415

  11. Partial oxidation of step-bound water leads to anomalous pH effects on metal electrode step-edges.

    Science.gov (United States)

    Schwarz, Kathleen; Xu, Bingjun; Yan, Yushan; Sundararaman, Ravishankar

    2016-06-28

    The design of better heterogeneous catalysts for applications such as fuel cells and electrolyzers requires a mechanistic understanding of electrocatalytic reactions and the dependence of their activity on operating conditions such as pH. A satisfactory explanation for the unexpected pH dependence of electrochemical properties of platinum surfaces has so far remained elusive, with previous explanations resorting to complex co-adsorption of multiple species and resulting in limited predictive power. This knowledge gap suggests that the fundamental properties of these catalysts are not yet understood, limiting systematic improvement. Here, we analyze the change in charge and free energies upon adsorption using density-functional theory (DFT) to establish that water adsorbs on platinum step edges across a wide voltage range, including the double-layer region, with a loss of approximately 0.2 electrons upon adsorption. We show how this as-yet unreported change in net surface charge due to this water explains the anomalous pH variations of the hydrogen underpotential deposition (Hupd) and the potentials of zero total charge (PZTC) observed in published experimental data. This partial oxidation of water is not limited to platinum metal step edges, and we report the charge of the water on metal step edges of commonly used catalytic metals, including copper, silver, iridium, and palladium, illustrating that this partial oxidation of water broadly influences the reactivity of metal electrodes.

  12. Water molecules orientation in surface layer

    Science.gov (United States)

    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.

  13. Water-to-air transfer of branched and linear PFOA: Influence of pH, concentration and water type

    Directory of Open Access Journals (Sweden)

    Jana H. Johansson

    2017-03-01

    Full Text Available The volatilisation of perfluorooctanoic acid (PFOA was measured experimentally at a range of pH values using a previously published laboratory method. Water-to-air transfer was studied for five structural isomers, namely: the linear isomer (n-PFOA and the four most commonly occurring branched isomers (3-, 4-, 5- and 6-PFOA. The influence of water concentration and water type on the pH-dependent water-to-air transfer was also investigated for n-PFOA. The water-to-air transfer was studied over the course of 48 h at pH values ranging from 0.2 to 5.5. Under all experimental conditions tested, the volatilisation of PFOA was negligible at pH > 2.5. In experiments performed with MilliQ water, volatilisation increased with decreasing water pH. In experiments performed with tap water and lake water, maximum volatilisation was observed at pH 1. The concentration of PFOA in water had no influence on the pH value at which water-to-air transfer was observed (i.e. at pH < 2.5 for the concentration range tested (0.1–50 μg/L PFOA in deionised water. Although the percentage of PFOA volatilised was significantly different for the four branched isomers at low pH, volatilisation was not observed above pH 2.5 for any branched isomer suggesting that all PFOA isomers have a low pKa. Overall, these laboratory results demonstrate that volatilisation of any structural isomer of PFOA from water is negligible at environmentally-relevant conditions. It is unlikely that PFOA isomers will be fractionated in the environment as a result of volatilisation because it is a process of negligible environmental relevance.

  14. Controlled surface adsorption of fd filamentous phage by tuning of the pH and the functionalization of the surface

    Science.gov (United States)

    Jeon, Dae-Young; Hwang, Kyung Hoon; Park, So-Jeong; Kim, Yun-Jeong; Joo, Min-Kyu; Ahn, Seung-Eon; Kim, Gyu-Tae; Nam, Chang-Hoon

    2011-03-01

    The surface adsorption of fd filamentous phage (fd phage) dispersed in different solution pHs was investigated with functionalized SiO2/Si substrates. The fd phages at high pH (˜9.0) were well-adsorbed on the SiO2/Si surface that was functionalized by 3-aminopropyltriethoxysilane, whereas those at low pH (˜3.0) were well-adsorbed on the cleaned SiO2/Si surface. The high affinity of the carboxylic acid groups (COO-) at high pH (˜9.0) was attributed to the fact that they give a higher adsorption to the positively charged amine groups (NH3+) on the surface of the substrate, similar to the effect of H3O+ at low pH (˜3.0) in a solution on the surface of the hydroxyl groups on the substrate (OH-). Interestingly, the aligned structures of the fd phage at intermediate pH (˜7.0), caused by the locally positively charged coat protein of the fd phage and the shear forces along the washing and blowing direction, were identified. The effective spring constant of the fd phage bundles was estimated to be 0.672 N/m using a force-distance curve. Our results offer prerequisite information for the bottom-up assembly in SiO2/Si substrates using the fd phage in bionanoelectronics.

  15. Trends and drivers in global surface ocean pH over the past three decades

    Directory of Open Access Journals (Sweden)

    S. K. Lauvset

    2014-11-01

    Full Text Available We report global long-term trends in surface ocean pH using a new pH data set computed by combining fCO2 observations from the Surface Ocean CO2 Atlas (SOCAT version 2 with surface alkalinity estimates based on temperature and salinity. Trends were determined over the periods 1981–2011 and 1991–2011 for a set of 17 biomes using a weighted linear least squares method. We observe significant decreases in surface ocean pH in ~70% of all biomes and a global mean rate of decrease of –0.0018 ± 0.0004 yr-1 for 1991–2011. We are not able to calculate a global trend for 1981–2011 because too few biomes have enough data for this. In two-thirds of the biomes, the rate of change is commensurate with the trends expected based on the assumption that the surface ocean pH change is only driven by the surface ocean carbon chemistry remaining in a transient equilibrium with the increase in atmospheric CO2. In the remaining biomes deviations from such equilibrium may reflect changes in the trend of surface ocean fCO2, most notably in the equatorial Pacific Ocean, or changes in the oceanic buffer (Revelle factor. We conclude that well-planned and long-term sustained observational networks are key to reliably document the ongoing and future changes in ocean carbon chemistry due to anthropogenic forcing.

  16. Long-term effects of water pH changes on hematological parameters ...

    African Journals Online (AJOL)

    Yomi

    2012-02-14

    Feb 14, 2012 ... face between fish and its environment for gas transfer, acid-base ... and low water pH on ion balance and ammonia excretion in freshwater fish ... Water quality parameters of the stored water were measured at the beginning of ...

  17. Modelling global fresh surface water temperature

    NARCIS (Netherlands)

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

    2011-01-01

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

  18. Modelling global fresh surface water temperature

    NARCIS (Netherlands)

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

    2011-01-01

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

  19. Changes in the size of the apparent surface area and adsorption energy of the rye roots by low pH and the presence of aluminium ions induced

    Science.gov (United States)

    Szatanik-Kloc, Alicja

    2016-07-01

    The plant reactions on Al-stress include i.a. change of the surface area of the roots, which in the physicochemistry of plants characterizes the transport of water and ions through the root. The object of this study is the specific surface area of the roots of plants which are tolerant to aluminium, such as rye. Plants of rye were grown in a nutrient solution for 14 days at pH 4.5 in the presence of Al3+ ions of concentration 10, 20, and 40 mg dm-3. The control plants were grown continuously at pH 7 or pH 4.5 without Al3+. The apparent surface area and adsorption energy of the plants roots were determined from water vapour adsorption - desorption data. The apparent surface area of roots growing in the aluminium was (with respect to control) statistically significantly lower. There were no statistically significant differences in the apparent surface area of the roots which grew in pH 7, pH 4.5 without Al3+. The average water vapour adsorption energy of the root surface, under stress conditions decreased. In the roots grown in the presence of Al+3, there was a slight decrease in high energy adsorption centres and an increase in the amount of low-energy centres.

  20. Investigations into aggregate formation with oppositely charged oil-in-water emulsions at different pH values.

    Science.gov (United States)

    Maier, Christiane; Zeeb, Benjamin; Weiss, Jochen

    2014-05-01

    The pH-dependent formation and stability of food-grade heteroaggregates from oppositely charged oil-in-water (O/W) emulsions was investigated. After screening suitable emulsifiers, 10% (w/w) oil in-water emulsions (d32≈1 μm) were prepared at pH 3-7 using a positively charged emulsifier (Na-lauroyl-l-arginine ethyl ester; LAE) and four negatively charged ones (citric esters of mono- and diglycerides, soy lecithin, sugar beet pectin, and Quillaja saponin). The oppositely charged emulsions were then combined at constant pH values at a volume flow rate ratio of 1:1. Emulsions and heteroaggregates were characterized by their surface charge, particle size distribution and microstructure using dynamic and static light scattering as well as confocal laser scanning microscopy. The emulsifier type was found to greatly influence the type of heteroaggregates formed, as well as the pH value, specifically in combined LAE/Quillaja saponin emulsions. Larger aggregates particularly were formed with increasing pH values (2.71±1.21 to 46.53±4.30 μm from pH 3 to 7, respectively), while LAE/pectin aggregates appeared not to be affected by pH over the full pH range investigated (3.80±2.89 to 3.94±2.78 μm from pH 3 to 7, respectively). Our study thus provides valuable first insights into the mechanism of the formation of food-grade heteroaggregates for later use in food systems. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Rocky Mountain Arsenal surface water management plan : water year 2003

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Surface Water Management Plan (SWMP) for Water Year 2003 (WY 2003) (October I, 2002 to September 30, 2003) is an assessment of the nonpotable water demands at...

  2. Rocky Mountain Arsenal surface water management plan : water year 2005

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Surface Water Management Plan for Water Year (WY) 2005 (October 1, 2004 to September 30, 2005) is an assessment of the nonpotable water demands at the Rocky...

  3. Rocky Mountain Arsenal surface water management plan : water year 2006

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Surface Water Management Plan for Water Year (WY) 2006 (October 1, 2005 to September 30, 2006) is an assessment of the nonpotable water demands at the Rocky...

  4. Importance of sample pH on recovery of mutagenicity from drinking water by XAD resins

    Energy Technology Data Exchange (ETDEWEB)

    Ringhand, H.P.; Meier, J.R.; Kopfler, F.C.; Schenck, K.M.; Kaylor, W.H.; Mitchell, D.E.

    1987-04-01

    Sample pH and the presence of a chlorine residual were evaluated for their effects of the recovery of mutagenicity in drinking water following concentration by XAD resins. The levels of mutagenicity in the pH 2 concentrates were 7-8-fold higher than those of the pH 8 concentrates, suggesting that acidic compounds accounted for the majority of the mutagenicity. The presence of a chlorine residual had little effect on the levels of mutagenicity at either pH. Comparisons of the mutagenic activity for the pH 2 resin concentrates vs. pH 8 concentrates prepared by lyophilization further indicated that the acidic mutagens were products of disinfection with chlorine and not artifacts of the sample acidification step in the concentration procedure. 27 references, 6 figures, 1 table.

  5. Surface water discharges from onshore stripper wells.

    Energy Technology Data Exchange (ETDEWEB)

    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.

  6. Analysis of pH on Water Temperature in the Recirculation Sump

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sang Nyung; Yoon, Hyoung Ju [Kyunghee University, Yongin (Korea, Republic of)

    2010-10-15

    During a loss-of-coolant accident (LOCA) in a pressurized water reactor (PWR), remedial actions initiated automatically include actuation of the containment spray system (CSS) in most plants and actuation of the emergency core cooling system (ECCS) to provide an emergency supply of borated water from the in-containment refueling water storage tank (IRWST). The reactor coolant, containment spray, and borated water injected by the ECCS drain to the floor of the containment building and are collected by the recirculation sump. After the initiation of these actions, the recirculation sump would contain boric acid and tri-sodium phosphate (TSP) that is held dry in the sump to neutralize the boric acid. These materials have influence on pH and the sump pH is dependent on the amount of TSP under the variable conditions such as sump water level, boron concentration for each water source and sump water temperature. The equilibrium sump solution pH should be above 7.0 according to the Standard Review Plan. The purpose of controlling the sump pH is to provide assurance that significant long-term iodine revolution does not occur, and to be within material compatibility constraints. It has been the domestic practice that the pH value of sump water following a LOCA was computed by a chemical equilibrium calculation involving equilibrium constants or ionization constants. However, in this paper, the sump pH analysis has been performed by the modified SOLGASMIX-PV program which computes thermodynamic equilibrium compositions involving the Gibbs free energy and pH for each sump condition

  7. pH dependence of friction forces between silica surfaces in solutions.

    Science.gov (United States)

    Taran, Elena; Donose, Bogdan C; Vakarelski, Ivan U; Higashitani, Ko

    2006-05-01

    The pH dependence of the friction between a silica particle and a silica wafer was investigated using lateral force microscopy. Measurements were done in the range of 3.6 < or = pH < or = 10.6 and the effect of high loading force was also examined. It is found that the friction is independent of the pH of solutions and increases linearly with the applied load, when the pH is between 3.6 and 8.6. On the other hand, once the pH is above 9.0, the friction becomes extremely small and the dependence on the applied load becomes nonlinear. It is postulated that this transition is due to the development of a gel layer composed of polymer-like segments of silicilic acid anchored on the surface; at the lower applied load, this layer acts as a boundary lubricant between the surfaces, but, at the higher applied load, the entanglements of these segments and more direct contact between two solid surfaces leads to the increase of the friction. The effects found here are expected to play an important role in elucidating the basic mechanism of the planarization process of silica wafers.

  8. Estimation of water activity from pH and °Brix values of some food products.

    Science.gov (United States)

    Gabriel, Alonzo A

    2008-06-01

    In this study, a predictive model for the estimation of water activity (aw(25°C)) as a function of pH (1.00-8.00) and °Brix (0-82.00) values of simulated food solutions (SFS) was developed, through response surface methodology. Response fit analyses resulted in a highly significant (pHBrix values within the defined variable ranges. The linear, quadratic and interactive influences of pH and °Brix on aw(25°C) were all significant (pH<0.0001). Model validations in SFS and in a number of actual food systems showed that the model had acceptable predictive performance, as indicated by the calculated accuracy and bias indices.

  9. Particle water and pH in the southeastern United States

    Science.gov (United States)

    Guo, H.; Xu, L.; Bougiatioti, A.; Cerully, K. M.; Capps, S. L.; Hite, J. R.; Carlton, A. G.; Lee, S.-H.; Bergin, M. H.; Ng, N. L.; Nenes, A.; Weber, R. J.

    2014-10-01

    Particle water and pH are predicted using thermodynamic modeling (with ISORROPIA-II), meteorological observations (RH, T), and gas/particle composition. A comprehensive uncertainty analysis is included and the model validated with ammonia partitioning. The method is applied to predict mass concentrations of particle water and related particle pH for ambient fine mode aerosols sampled in a relatively remote Alabama forest during the Southern Oxidant and Aerosol Study (SOAS) in summer, and at various sites in the southeastern US, during different seasons, as part of the Southeastern Center for Air Pollution and Epidemiology (SCAPE) study. Particle water and pH are closely linked; pH is a measure of the particle H+ aqueous concentration, and so depends on both the presence of ions and amount of particle liquid water. Levels of particle water, in-turn, are determined through water uptake by both the ionic species and organic compounds. Particle ion balances, often used to infer pH, do not consider either the dissociation state of individual ions, nor particle liquid water levels and so do not necessarily correlate with particle pH. Thermodynamic calculations based on measured ion concentrations can predict both pH and liquid water, but do not consider contributions of organic species to liquid water and so may also be biased. In this study, contributions of both inorganic and organic fractions to aerosol liquid water were considered and predictions were in good agreement with measured liquid water based on differences in ambient and dry light scattering coefficients (prediction vs. measurement: slope = 0.91, intercept = 0.45 μg m-3, R = 0.87). ISORROPIA-II predictions were evaluated by reproducing the observed gas-particle partitioning of NH3. Based on this study, organic species on average contributed 35% to the total water, with a substantially higher contribution (63%) at night. The mean pH predicted in the Alabama forest (SOAS) was 0.94 ± 0.59 (median 0.93). Not

  10. Single molecule force measurements delineate salt, pH and surface effects on biopolymer adhesion

    Science.gov (United States)

    Pirzer, T.; Geisler, M.; Scheibel, T.; Hugel, T.

    2009-06-01

    In this paper we probe the influence of surface properties, pH and salt on the adhesion of recombinant spider silk proteins onto solid substrates with single molecule force spectroscopy. A single engineered spider silk protein (monomeric C16 or dimeric (QAQ)8NR3) is covalently bound with one end to an AFM tip, which assures long-time measurements for hours with one and the same protein. The tip with the protein is brought into contact with various substrates at various buffer conditions and then retracted to desorb the protein. We observe a linear dependence of the adhesion force on the concentration of three selected salts (NaCl, NaH2PO4 and NaI) and a Hofmeister series both for anions and cations. As expected, the more hydrophobic C16 shows a higher adhesion force than (QAQ)8NR3, and the adhesion force rises with the hydrophobicity of the substrate. Unexpected is the magnitude of the dependences—we never observe a change of more than 30%, suggesting a surprisingly well-regulated balance between dispersive forces, water-structure-induced forces as well as co-solute-induced forces in biopolymer adhesion.

  11. Adhesion of Pathogenic Bacteria to Food Contact Surfaces: Influence of pH of Culture

    Directory of Open Access Journals (Sweden)

    Akier Assanta Mafu

    2011-01-01

    Full Text Available The adhesion of Aeromonas hydrophila, Escherichia coli O157:H7, Salmonella Enteritidis, and Staphylococcus aureus to hydrophobic and hydrophilic surfaces in cultures with different pHs (6, 7, and 8 was studied. The results indicated that the type of material had no effect on the attachment capacity of microorganisms, while environmental pH influenced the adhesion of A. hydrophila, E. coli, and S. aureus to both solid substrates. The attachment of S. Enteritidis (P>.05 was not affected by the type of substrate or the culture pH, whereas E. coli displayed the weakest affinity for both polystyrene and glass surfaces. No correlation was established between the physicochemical properties of the materials, or the bacterial and the rate of bacterial adhesion, except for S. aureus. Photomicrographs have shown that surfaces were contaminated by small clusters of S. Enteritidis while S. aureus invaded the food contact surfaces in the form of small chains or cell aggregates.

  12. Water surface capturing by image processing

    Science.gov (United States)

    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...

  13. Observation of temperature and pH during biogas production from water hyacinth and cow manure

    Directory of Open Access Journals (Sweden)

    Nurfitri Astuti

    2013-11-01

    Full Text Available Biogas is generated from biological process of organic material by bacterial engaged. Biogas can be derived from manure, municipal waste, agricultural waste and other biomass resources. In addition to the use of cow manure as raw material for biogas production, it can also be derived from biomass containing cellulose which one is water hyacinth as an organic material that contains quite large cellulose. The abundance of water hyacinth found in Rawapening causing several negative impacts. The purpose of this study is to observe  temperature and pH on the biogas production generated from water hyacinth of Rawapening and cow manure. Biogas production process begins by chopping the leaves and stems of water hyacinth, and then mixed with cow manure and water. The results of substrate variation of water hyacinth, cow manure and water reaches optimally at 40:80:480 respectively, which produce the highest point of  biogas amounted 176.33 ml on the day 20 in 1L sized digester, the temperature of the biogas production is at 32°C.  At the initial fermentation, digester temperature of 30°C has increased over the course of the fermentation process, a peak at day 20 and then decreased to 27°C at the end of fermentation. There is a decrease in pH starting from initial fermentation at pH 6-7 and then the pH began to decline until the end of fermentation as amount of pH 5.Doi: http://dx.doi.org/10.12777/wastech.1.1.22-25Citation:  Nurfitri Astuti, N., Tri Retnaningsih Soeprobowati, T.R., and  Budiyono. 2013. Observation of temperature and pH during biogas production from water hyacinth and cow manure. Waste Technology 1(1:1-5. Doi: http://dx.doi.org/10.12777/wastech.1.1.22-25

  14. Application of adsorption methods to determine the effect of pH and Cu-stress on the changes in the surface properties of the roots

    Science.gov (United States)

    Szatanik-Kloc, Alicja

    2014-10-01

    Rye plants were grown in a nutrient solution prepared according to Hoagland for 2 weeks at pH 7, next for 14 days at pH 4.5 (without Cu+2) and in the presence of 20, 50, or 100 mg dm-3 copper ions. The control plants were grown continuously at pH 7. The physicochemical surface properties of the roots were examined using two adsorbates - polar (water vapour) and non-polar (nitrogen). The surface properties of the roots grown at pH 4.5 without Cu+2 were apparently the same as those of controls. The roots of rye which grew in the presence of Cu+2 were characterized by lower (relative to controls) specific surface area values. Statistically significant differences in the size of the apparent surface area (determined by water vapour) were reported for roots incubated with copper ions at a concentration of 20 and 50 mg dm-3. The average water vapour adsorption energy of the root surface decreased under the stress conditions. There were no statistically significant differences for the free surface area and characteristic energy of nitrogen adsorption.

  15. Optical pH measurements with water dispersion of polyaniline nanoparticles and their redox sensitivity.

    Science.gov (United States)

    Lindfors, Tom; Harju, Leo; Ivaska, Ari

    2006-05-01

    A new method for optical pH and redox measurements with a commercially available water dispersion of polyaniline (PANI) nanoparticles (mean particle size, 46 nm) is presented. The pH measurements are based on the acid-base equilibrium of PANI and were carried out either by combining both the automated sequential injection analysis (SIA) and UV-visible spectrophotometric techniques or with a fiber-optic light guide. In the former case, the detection was done in continuous mode at lambda = 800 nm by using the SIA technique for transporting the sample to a flow-through cell, which was placed in the light path of the photometer. With the fiber-optic light guide, the detection was done in batch mode at lambda = 400 and 580 nm. In both methods, fresh pH reagent (PANI) solution was used in each measurement, thus overcoming the problem with hysteresis (memory effect), which is usually observed with PANI films. The PANI nanoparticles were characterized with UV-visible spectroscopy in pH buffer solutions between pH 2-12 and a protonation constant of logK(0.5H,L)(H(0.5)L) = 4.4 was calculated from these data. Fast pH measurements can be done between pH 6 and 10.5 depending on the measuring technique. It is possible to determine pH with an accuracy of 0.1 pH unit between pH 8 and 10.5 (RSD, 0.5-2%). Redox transitions typical for PANI films were also observed for water solutions of PANI nanoparticles in the presence of the hexacyanoferrate(II/III) and the iron(II/III) oxalate redox couples. The absorbance at lambda = 875 nm is linearly dependent on the logarithm of the concentration ratio (0.1-10) of the iron oxalate redox couple.

  16. Water soluble drug releasing soft contact lens in response to pH of tears

    Science.gov (United States)

    Kim, G.; Noh, H.

    2016-06-01

    Human tear characteristics including pH and compositions can vary significantly depending on physical and environmental factors. Contact lenses directly contact with human tears can be swelled or de-swelled depending on the pH of the solution due to the nature of the hydrogel. For examples, anionic hydrogels, when the solution's pH is low, is shrunken due to the electric attraction force within the hydrogel network; the opposite phenomenon appears when the solution is basic. The purpose of this study was to evaluate the extent of water soluble drug, hydroxyl propyl methyl cellulose, released from contact lens according to the pH of the artificial tears. Artificial tears are prepared by mixing lysozyme, albumin, sodium chloride, potassium chloride, and calcium chloride following physiological concentrations. Hydrogel contact lens was thermally polymerized using HEMA, EGDMA, and AIBN. The prepared hydrogel lens was immersed in drug for 3 hours and the eluted drug mass was measured as a function of the time. As a result, the drug was released from the lens for 12 hours in all the pH of artificial tears. At the lower pH of artificial tears (pH 5.8), the total amount of dye emitted from the lens was increased than the total amount of dye emitted at the basic tear (pH 8.4). Also, initial burst at acidic tears was increased within 1 hour. Release pattern of water-soluble drug from hydrogel lens turned out to be different depending on the pH of the artificial tears. When designing drug releasing contact lens, physiological pH of tears should be considered.

  17. Water balance creates a threshold in soil pH at the global scale

    Science.gov (United States)

    Slessarev, E. W.; Lin, Y.; Bingham, N. L.; Johnson, J. E.; Dai, Y.; Schimel, J. P.; Chadwick, O. A.

    2016-12-01

    Soil pH regulates the capacity of soils to store and supply nutrients, and thus contributes substantially to controlling productivity in terrestrial ecosystems. However, soil pH is not an independent regulator of soil fertility—rather, it is ultimately controlled by environmental forcing. In particular, small changes in water balance cause a steep transition from alkaline to acid soils across natural climate gradients. Although the processes governing this threshold in soil pH are well understood, the threshold has not been quantified at the global scale, where the influence of climate may be confounded by the effects of topography and mineralogy. Here we evaluate the global relationship between water balance and soil pH by extracting a spatially random sample (n = 20,000) from an extensive compilation of 60,291 soil pH measurements. We show that there is an abrupt transition from alkaline to acid soil pH that occurs at the point where mean annual precipitation begins to exceed mean annual potential evapotranspiration. We evaluate deviations from this global pattern, showing that they may result from seasonality, climate history, erosion and mineralogy. These results demonstrate that climate creates a nonlinear pattern in soil solution chemistry at the global scale; they also reveal conditions under which soils maintain pH out of equilibrium with modern climate.

  18. Effects of diferent salivary ph on the surface and roughness of different orthodontic wires

    OpenAIRE

    2015-01-01

    AIM: The aim of this study was to evaluate the effects of different salivary pH on the surface of orthodontic wires. MATERIAL AND METHODS: Two hundred and seventy wire segments of titanium-molybdenum alloy (TMA), and Cr-Ni stainless steel , subjected to saliva pH 2.0 , 5.0 and 7.6 , in three different times of storage, divided into 3 groups (n=30). Group 1: TMA (Morelli), Group 2: TMA (Ormco) and Group 3: Stainless steel Cr-Ni (Morelli). To read the roughness profilometer was used Mitutoyo Su...

  19. ASSESSMENT OF SURFACE WATER QUALITY IN AN ARSENIC CONTAMINATED VILLAGE

    Directory of Open Access Journals (Sweden)

    Kumud C. Saikia

    2012-01-01

    Full Text Available Arsenic contamination of ground water has occurred in various parts of the world, becoming a menace in the Ganga-Meghna-Brahmaputra basin (West Bengal and Assam in India and Bangladesh. Recently arsenic has been detected in Cachar and Karimganj districts of barak valley, Assam, bordering Bangladesh. In this area coli form contamination comprises the major constraint towards utilization of its otherwise ample surface water resources. The local water management exploited ground water sources using a centralized piped water delivery scheme without taking into account the geologically arsenic-prone nature of the sediments and aquifers in this area. Thus surface water was the suggestive alternative for drinking water in this area. The present study investigated surface water quality and availability in a village of Karimganj district, Assam, India contaminated with arsenic for identifying the potential problems of surface water quality maintenance so that with effective management safe drinking water could be provided. The study revealed that the area was rich in freshwater ecosystems which had all physico-chemical variables such as water temperature, pH, DO, total alkalinity, free CO2, heavy metals like lead, chromium and cadmium within WHO standards. In contrast, coli form bacteria count was found far beyond permissible limit in all the sources. Around 60% people of the village preferred ground water for drinking and only 6% were aware of arsenic related problems. The problem of bacterial contamination could be controlled by implementing some ameliorative measures so that people can safely use surface water. Inhabitants of the two districts should be given proper education regarding arsenic contamination and associated health risk. Effluents should be treated to acceptable levels and standards before discharging them into natural streams.

  20. Safe Drinking Water Information System (SDWIS) Surface Water Intakes

    Data.gov (United States)

    U.S. Environmental Protection Agency — This is a point feature dataset showing the locations of surface water intakes. These intake locations are part of the safe drinking water information system...

  1. Tuning the Structure and Rheology of Polystyrene Particles at the Air-Water Interface by Varying the pH.

    Science.gov (United States)

    Truzzolillo, Domenico; Sharaf, Hossameldeen; Jonas, Ulrich; Loppinet, Benoit; Vlassopoulos, Dimitris

    2016-07-12

    We form films of carboxylated polystyrene particles (C-PS) at the air-water interface and investigate the effect of subphase pH on their structure and rheology by using a suite of complementary experimental techniques. Our results suggest that electrostatic interactions drive the stability and the structural order of the films. In particular, we show that by increasing the pH of the subphase from 9 up to 13, the films exhibit a gradual transition from solid to liquidlike, which is accompanied by a loss of the long-range order (that characterizes them at lower values of pH). Direct optical visualization of the layers, scanning electron microscopy, and surface pressure isotherms indicate that the particles deposited at the interface form three-dimensional structures involving clusters, with the latter being suppressed and a quasi-2D particle configuration eventually reached at the highest pH values. Evidently, the properties of colloidal films can be tailored significantly by altering the pH of the subphase.

  2. Regulation and Functional Significance of Airway Surface Liquid pH

    Directory of Open Access Journals (Sweden)

    Coakley RD

    2001-07-01

    Full Text Available In gastrointestinal tissues, cumulative evidence from both in vivo and in vitro studies suggests a role for the cystic fibrosis transmembrane conductance regulator (CFTR in apical epithelial bicarbonate conductance. Abnormal lumenal acidification is thus hypothesized to play a role in the genesis of cystic fibrosis (CF pancreatic disease. However, consensus regarding CFTR's participation in pH regulation of airway surface liquid (ASL and thus the contribution of ASL pH to the etiology of CF lung disease, is lacking. The absence of data reflects difficulties in both sampling ASL in vivo and modeling ASL biology in vitro. Here we evaluate the evidence in support of a lumenal acidification hypothesis in the CF lung, summarize current knowledge of pH regulation in the normal airway and illustrate how hyper-acidified airway secretions could contribute to the pathogenesis of CF lung disease.

  3. Molecular modeling of the surface charging of hematite. II. Optimal proton distribution and simulation of surface charge versus pH relationships

    Science.gov (United States)

    Rustad, James R.; Wasserman, Evgeny; Felmy, Andrew R.

    1999-03-01

    A parameterized classical potential model for the interaction of water and hydroxide with iron oxide was used to calculate the optimal proton arrangement and proton binding energies on the (012) surface of hematite. Energy minimization calculations with the parameterized potential model indicate that approximately 75% of adsorbed water molecules are dissociated on this surface, in agreement with recent TPD and HREELS measurements. Surface protonation/deprotonation energies were calculated from the predicted optimal arrangement of protons on the neutral (012) surface. A supercell geometry with translational symmetry in two dimensions and finite in the third dimension (2-D PBC) was assumed. The calculated surface protonation energies were then used to model the experimentally observed surface-charging curve of hematite in aqueous solution. Excellent agreement was found between the calculated and measured surface charge for ionic strengths ranging from 0.001 to 0.1 M. Our calculations favor the value of 8.5 for the pH of zero charge of hematite over the more recent result of 6.7.

  4. Anti-Aliased Rendering of Water Surface

    Institute of Scientific and Technical Information of China (English)

    Xue-Ying Qin; Eihachiro Nakamae; Wei Hua; Yasuo Nagai; Qun-Sheng Peng

    2004-01-01

    Water surface is one of the most important components of landscape scenes. When rendering spacious far from the viewpoint. This is because water surface consists of stochastic water waves which are usually modeled by periodic bump mapping. The incident rays on the water surface are actually scattered by the bumped waves,pattern, we estimate this solid angle of reflected rays and trace these rays. An image-based accelerating method is adopted so that the contribution of each reflected ray can be quickly obtained without elaborate intersection calculation. We also demonstrate anti-aliased shadows of sunlight and skylight on the water surface. Both the rendered images and animations show excellent effects on the water surface of a reservoir.

  5. Nanofiltration of Mine Water: Impact of Feed pH and Membrane Charge on Resource Recovery and Water Discharge

    Directory of Open Access Journals (Sweden)

    Mark Mullett

    2014-03-01

    Full Text Available Two nanofiltration membranes, a Dow NF 270 polyamide thin film and a TriSep TS 80 polyamide thin film, were investigated for their retention of ionic species when filtering mine influenced water streams at a range of acidic pH values. The functional iso-electric point of the membranes, characterized by changes in retention over a small pH range, were examined by filtering solutions of sodium sulphate. Both membranes showed changes in retention at pH 3, suggesting a zero net charge on the membranes at this pH. Copper mine drainage and synthetic solutions of mine influenced water were filtered using the same membranes. These solutions were characterized by pH values within 2 and 5, thus crossing the iso-electric point of both membranes. Retention of cations was maximized when the feed solution pH was less than the iso-electric point of the membrane. In these conditions, the membrane has a net positive charge, reducing the transmission rate of cations. From the recoveries of a range of cations, the suitability of nanofiltration was discussed relative to the compliance with mine water discharge criteria and the recovery of valuable commodity metals. The nanofiltration process was demonstrated to offer advantages in metal recovery from mine waste streams, concomitantly enabling discharge criteria for the filtrate disposal to be met.

  6. Effect of pH and Pressure on Uranium Removal from Drinking Water Using NF/RO Membranes.

    Science.gov (United States)

    Schulte-Herbrüggen, Helfrid M A; Semião, Andrea J C; Chaurand, Perrine; Graham, Margaret C

    2016-06-01

    Groundwater is becoming an increasingly important drinking water source. However, the use of groundwater for potable purposes can lead to chronic human exposure to geogenic contaminants, for example, uranium. Nanofiltration (NF) and reverse osmosis (RO) processes are used for drinking water purification, and it is important to understand how contaminants interact with membranes since accumulation of contaminants to the membrane surface can lead to fouling, performance decline and possible breakthrough of contaminants. During the current study laboratory experiments were conducted using NF (TFC-SR2) and RO (BW30) membranes to establish the behavior of uranium across pH (3-10) and pressure (5-15 bar) ranges. The results showed that important determinants of uranium-membrane sorption interactions were (i) the uranium speciation (uranium species valence and size in relation to membrane surface charge and pore size) and (ii) concentration polarization, depending on the pH values. The results show that it is important to monitor sorption of uranium to membranes, which is controlled by pH and concentration polarization, and, if necessary, adjust those parameters controlling uranium sorption.

  7. Intelligent smartphone-based portable network diagnostics for water security Case Study realtime pH mapping of tap water

    CERN Document Server

    Hossain, Arafat; Ast, Sandra; Rutledge, Peter J; Jamalipour, Abbas

    2014-01-01

    Using a field-portable, smartphone fluorometer to assess water quality based on the pH response of a designer probe, a map of pH of public tap water sites has been obtained. A custom designed Android application digitally processed and mapped the results utilizing the GPS service of the smartphone. The map generated indicates no disruption in pH for all sites measured. All the data are assessed to fall inside the upper limit of local government regulations and are consistent with authority reported measurements. The work demonstrates a new security concept: environmental forensics utilizing the advantage of real-time analysis for the detection of potential water quality disruption at any point in the city. The concept can be extended on national and global scales to a wide variety of analytes.

  8. SURFACE WATER QUALITY IN THE RIVER PRUT

    Directory of Open Access Journals (Sweden)

    MIHAELA DUMITRAN

    2011-03-01

    Full Text Available Water is an increasingly important and why it is important to surfacewater quality, which is given by the analysis of physical - chemical, biological andobserving the investigation of water, biota, environments investigation. Analysis ofthe Prut river in terms of biological and physical elements - chemical. Evaluationof ecological and chemical status of water was done according to order of approvalof the standard classification nr.161/2006 surface water to determine the ecologicalstatus of water bodies

  9. The pH effect on black spots in surface finish: Electroless nickel immersion gold

    Science.gov (United States)

    Won, Yong Sun; Park, Sung Soo; Lee, Jinuk; Kim, Jong-Yun; Lee, Seong-Jae

    2010-10-01

    In order to understand the black spot generation after electroless nickel immersion gold (ENIG) plating, we investigated the pH effect with a combined approach of experiments and computer aided engineering (CAE). As the pH is increased in IG plating solution, the deprotonation of citric acid as chelating agent is enhanced to stabilize the solution by producing Ni-citrate complex ion. For the substitution reaction between nickel and gold, excess citrate ions (deprotonated citric acids) are adsorbed along nodal boundaries of Ni-P layer to decrease the surface reactivity. Since the low reactivity decreases the overall growth rate, the resulting homogeneous Au layer growth avoids the unfavorable galvanic cell corrosion to control black spot. Based on molecular orbital method and kinetic Monte Carlo calculation, our computational approach well explained the capability of citric acid as chelating agent and the Au growth rate along the nodal boundaries of Ni-P layer depending on the surface reactivity.

  10. Extremely alkaline (pH > 12) ground water hosts diverse microbial community.

    Science.gov (United States)

    Roadcap, George S; Sanford, Robert A; Jin, Qusheng; Pardinas, José R; Bethke, Craig M

    2006-01-01

    Chemically unusual ground water can provide an environment for novel communities of bacteria to develop. Here, we describe a diverse microbial community that inhabits extremely alkaline (pH > 12) ground water from the Lake Calumet area of Chicago, Illinois, where historic dumping of steel slag has filled in a wetland. Using microbial 16S ribosomal ribonucleic acid gene sequencing and microcosm experiments, we confirmed the presence and growth of a variety of alkaliphilic beta-Proteobacteria, Bacillus, and Clostridium species at pH up to 13.2. Many of the bacterial sequences most closely matched those of other alkaliphiles found in more moderately alkaline water around the world. Oxidation of dihydrogen produced by reaction of water with steel slag is likely a primary energy source to the community. The widespread occurrence of iron-oxidizing bacteria suggests that reduced iron serves as an additional energy source. These results extend upward the known range of pH tolerance for a microbial community by as much as 2 pH units. The community may provide a source of novel microbes and enzymes that can be exploited under alkaline conditions.

  11. Ground and river water quality monitoring using a smartphone-based pH sensor

    Directory of Open Access Journals (Sweden)

    Sibasish Dutta

    2015-05-01

    Full Text Available We report here the working of a compact and handheld smartphone-based pH sensor for monitoring of ground and river water quality. Using simple laboratory optical components and the camera of the smartphone, we develop a compact spectrophotometer which is operational in the wavelength range of 400-700 nm and having spectral resolution of 0.305 nm/pixel for our equipment. The sensor measures variations in optical absorption band of pH sensitive dye sample in different pH solutions. The transmission image spectra through a transmission grating gets captured by the smartphone, and subsequently converted into intensity vs. wavelengths. Using the designed sensor, we measure water quality of ground water and river water from different locations in Assam and the results are found to be reliable when compared with the standard spectrophotometer tool. The overall cost involved for development of the sensor is relatively low. We envision that the designed sensing technique could emerge as an inexpensive, compact and portable pH sensor that would be useful for in-field applications.

  12. Ground and river water quality monitoring using a smartphone-based pH sensor

    Science.gov (United States)

    Dutta, Sibasish; Sarma, Dhrubajyoti; Nath, Pabitra

    2015-05-01

    We report here the working of a compact and handheld smartphone-based pH sensor for monitoring of ground and river water quality. Using simple laboratory optical components and the camera of the smartphone, we develop a compact spectrophotometer which is operational in the wavelength range of 400-700 nm and having spectral resolution of 0.305 nm/pixel for our equipment. The sensor measures variations in optical absorption band of pH sensitive dye sample in different pH solutions. The transmission image spectra through a transmission grating gets captured by the smartphone, and subsequently converted into intensity vs. wavelengths. Using the designed sensor, we measure water quality of ground water and river water from different locations in Assam and the results are found to be reliable when compared with the standard spectrophotometer tool. The overall cost involved for development of the sensor is relatively low. We envision that the designed sensing technique could emerge as an inexpensive, compact and portable pH sensor that would be useful for in-field applications.

  13. Manufacturing and characterisation of water repellent surfaces

    DEFF Research Database (Denmark)

    De Grave, Arnaud; Botija, Pablo; Hansen, Hans Nørgaard

    2006-01-01

    design criteria for such surfaces. The problem of adapting this behaviour to artificially roughened surfaces is addressed by providing design criteria for superhydrophobic, water-repellent and self-cleaning surfaces according to the concrete performance desired for them. Different kind of manufacturing...

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

    Energy Technology Data Exchange (ETDEWEB)

    Ruma,; Yoshihara, K. [Graduate School of Science and Technology, Kumamoto University, Kumamoto 860-8555 (Japan); Hosseini, S. H. R., E-mail: hosseini@kumamoto-u.ac.jp; Sakugawa, T.; Akiyama, H. [Graduate School of Science and Technology, Kumamoto University, Kumamoto 860-8555 (Japan); Institute of Pulsed Power Science, Kumamoto University, Kumamoto 860-8555 (Japan); Akiyama, M. [Department of Electrical and Electronic Engineering, Kagoshima University, Kagoshima 890-0065 (Japan); Lukeš, P. [Institute of Plasma Physics, AS CR, Prague, Prague 18200 (Czech Republic)

    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.

  15. Influence of pH, bleaching agents, and acid etching on surface wear of bovine enamel

    Directory of Open Access Journals (Sweden)

    Ana Flávia Soares

    2016-02-01

    Full Text Available ABSTRACT Development of new materials for tooth bleaching justifies the need for studies to evaluate the changes in the enamel surface caused by different bleaching protocols. Objective The aim of this study was to evaluate the bovine dental enamel wear in function of different bleaching gel protocols, acid etching and pH variation. Material and Methods Sixty fragments of bovine teeth were cut, obtaining a control and test areas. In the test area, one half received etching followed by a bleaching gel application, and the other half, only the bleaching gel. The fragments were randomly divided into six groups (n=10, each one received one bleaching session with five hydrogen peroxide gel applications of 8 min, activated with hybrid light, diode laser/blue LED (HL or diode laser/violet LED (VHL (experimental: Control (C; 35% Total Blanc Office (TBO35HL; 35% Lase Peroxide Sensy (LPS35HL; 25% Lase Peroxide Sensy II (LPS25HL; 15% Lase Peroxide Lite (LPL15HL; and 10% hydrogen peroxide (experimental (EXP10VHL. pH values were determined by a pHmeter at the initial and final time periods. Specimens were stored, subjected to simulated brushing cycles, and the superficial wear was determined (μm. ANOVA and Tukey´s tests were applied (α=0.05. Results The pH showed a slight decrease, except for Group LPL15HL. Group LPS25HL showed the highest degree of wear, with and without etching. Conclusion There was a decrease from the initial to the final pH. Different bleaching gels were able to increase the surface wear values after simulated brushing. Acid etching before bleaching increased surface wear values in all groups.

  16. Surface degradation of dental ceramics as a function of environmental pH.

    Science.gov (United States)

    Esquivel-Upshaw, J F; Dieng, F Y; Clark, A E; Neal, D; Anusavice, K J

    2013-05-01

    We tested the hypotheses that glass-ceramic veneers and overglazes degrade by ion exchange in an acidic environment, and that they degrade by breakdown of the silica network in a basic environment. Disk specimens of glass-ceramic veneer and glaze were fabricated and immersed in pH 2, 7, or 10 buffer solutions, for 1, 3, 5, 10, 15, and 30 days. Each specimen was placed in a shaker bath containing de-ionized distilled water at 80°C. Concentrations of Al(3+), Ca(2+), Zn(2+), Li(2+), and Si(4+) were analyzed by means of inductively coupled plasma atomic emission spectrometry (ICP/AES). Statistical analyses were performed by factorial ANOVA. Significant differences occurred among leached ion concentrations as a function of material type, solution pH, and exposure time. A substantial release of Si occurred at pH 10 over time, leading to a breakdown of the glass phase. At pH 2, dissolution was controlled by an ionic exchange mechanism. We conclude that ceramic veneers and glazes may be susceptible to considerable degradation in low- and high-pH buffer solutions.

  17. Surface Water Quality Monitoring Sites

    Data.gov (United States)

    Minnesota Department of Natural Resources — The MN Department of Agriculture (MDA) is charged with periodically collecting and analyzing water samples from selected locations throughout the state to determine...

  18. The pH of water from various sources: an overview for recommendation for patients with atopic dermatitis

    OpenAIRE

    Kulthanan, Kanokvalai; Nuchkull, Piyavadee; Varothai, Supenya

    2013-01-01

    Background Patients with atopic dermatitis (AD) have increased susceptibility to irritants. Some patients have questions about types of water for bathing or skin cleansing. Objective We studied the pH of water from various sources to give an overview for physicians to recommend patients with AD. Methods Water from various sources was collected for measurement of the pH using a pH meter and pH-indicator strips. Results Bottled drinking still water had pH between 6.9 and 7.5 while the sparkling...

  19. The pH of water from various sources: an overview for recommendation for patients with atopic dermatitis

    OpenAIRE

    Kulthanan, Kanokvalai; Nuchkull, Piyavadee; Varothai, Supenya

    2013-01-01

    Background Patients with atopic dermatitis (AD) have increased susceptibility to irritants. Some patients have questions about types of water for bathing or skin cleansing. Objective We studied the pH of water from various sources to give an overview for physicians to recommend patients with AD. Methods Water from various sources was collected for measurement of the pH using a pH meter and pH-indicator strips. Results Bottled drinking still water had pH between 6.9 and 7.5 while the sparkling...

  20. Adsorption of Hydrophobin-Protein Mixtures at the Air-Water Interface: The Impact of pH and Electrolyte.

    Science.gov (United States)

    Tucker, Ian M; Petkov, Jordan T; Penfold, Jeffrey; Thomas, Robert K; Cox, Andrew R; Hedges, Nick

    2015-09-15

    The adsorption of the proteins β-casein, β-lactoglobulin, and hydrophobin, and the protein mixtures of β-casein/hydrophobin and β-lactoglobulin/hydrophobin have been studied at the air-water interface by neutron reflectivity, NR. Changing the solution pH from 7 to 2.6 has relatively little impact on the adsorption of hydrophobin or β-lactoglobulin, but results in a substantial change in the structure of the adsorbed layer of β-casein. In β-lactoglobulin/hydrophobin mixtures, the adsorption is dominated by the hydrophobin adsorption, and is independent of the hydrophobin or β-lactoglobulin concentration and solution pH. At pH 2.6, the adsorption of the β-casein/hydrophobin mixtures is dominated by the hydrophobin adsorption over the range of β-casein concentrations studied. At pH 4 and 7, the adsorption of β-casein/hydrophobin mixtures is dominated by the hydrophobin adsorption at low β-casein concentrations. At higher β-casein concentrations, β-casein is adsorbed onto the surface monolayer of hydrophobin, and some interpenetration between the two proteins occurs. These results illustrate the importance of pH on the intermolecular interactions between the two proteins at the interface. This is further confirmed by the impact of PBS, phosphate buffered saline, buffer and CaCl2 on the coadsorption and surface structure. The results provide an important insight into the adsorption properties of protein mixtures and their application in foam and emulsion stabilization.

  1. Cytotoxic and genotoxic potential of surface water from the Pitimbu river, northeastern/RN Brazil

    OpenAIRE

    Lucila Carmem Monte Egito; Maria das Graças Medeiros; Silvia Regina Batistuzzo de Medeiros; Lucymara Fassarella Agnez-Lima

    2007-01-01

    In this study, the onion (Allium cepa) root test was used to evaluate the genotoxicity of the Pitimbu River (Natal city, Brazil) surface water. The water was collected at five sampling sites along the river and one sample was obtained after the treatment (flocculation, chlorination and pH correction) of the river water for human consumption. All raw river water samples increased the frequency of chromosomal abnormalities and/or micronuclei and two of the water samples produced alterations in ...

  2. Preference behavior of silver catfish, Rhamdia quelen, juveniles in waters with pH gradients: laboratory experiments

    Directory of Open Access Journals (Sweden)

    Jaqueline Ineu Golombieski

    Full Text Available The aim of this study was to determine the preferred pH in silver catfish Rhamdia quelenjuveniles acclimated to different water hardness and the effect of shelters and infection by Ichthyophthirius multifiliis. Fish were acclimated for two weeks at different water hardness levels (4, 24, 50, or 100 mg CaCO3 L-1 and then transferred to a polyethylene tube with a pH gradient ranging from 3.5 to 11.7 and maintaining the same hardness. The position of the fish in the pH gradient was observed at 1, 2, 4, 6, 8, 10, and 12 h after transfer. Acclimation to different water hardness did not change pH preference of uninfected silver catfish (pH 7.30-7.83, and the presence of a shelter at the preferred pH or outside this preferred pH did not change the chosen pH range, either. Consequently silver catfish favored the acid-base regulation over shelter seeking tendency. Juveniles infected with I. multifiliis acclimated to water hardness of 24 mg CaCO3 L-1 preferred alkaline pH (9.08-9.79. This choice is not explained by the higher Na+ levels at alkaline pH compared to neutral pH because infected and uninfected fish choose the same waterborne Na+ levels in a Na+ gradient with the same pH.

  3. Surface Water Treatment Workshop Manual.

    Science.gov (United States)

    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…

  4. Spring and surface water quality of the Cyprus ophiolites

    Directory of Open Access Journals (Sweden)

    C. Neal

    2002-01-01

    Full Text Available A survey of surface, spring and borehole waters associated with the ophiolite rocks of Cyprus shows five broad water types (1 Mg-HCO3, (2 Na-SO4-Cl-HCO3, (3 Na-Ca-Cl-SO4-OH-CO3, (4 Na-Cl-SO4 and (5 Ca-SO4. The waters represent a progression in chemical reactivity from surface waters that evolve within a groundwater setting due to hydrolysis of the basic/ultrabasic rock as modified by CO2-weathering. An increase in salinity is also observed which is due to mixing with a saline end-member (modified sea-water and dissolution of gypsum/anhydrite. In some cases, the waters have pH values greater than 11. Such high values are associated with low temperature serpentinisation reactions. The system is a net sink for CO2. This feature is related not only to the hydrolysis of the primary minerals in the rock, but also to CaCO3 or Ca-Mg-CO3 solubility controls. Under hyperalkaline conditions, virtually all the carbon dioxide is lost from the water due to the sufficiently high calcium levels and carbonate buffering is then insignificant. Calcium sulphate solubility controls may also be operative when calcium and sulphate concentrations are particularly high. Keywords: Cyprus, Troodos, ophiolite, serpentinisation, spring, stream, water quality, bromide, iodine, boron, trace elements, hyperalkaline.

  5. Evidence for water structuring forces between surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Stanley, Christopher B [ORNL; Rau, Dr. Donald [National Institutes of Health

    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.

  6. pH and redox responsive polymer for antifouling surface coating

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kang Seok [Department of Chemical and Biological Engineering, Korea National University of Transportation, Chungju, 380-702 (Korea, Republic of); In, Insik, E-mail: in1@ut.ac.kr [Department of Polymer Science and Engineering, Korea National University of Transportation, Chungju, 380-702 (Korea, Republic of); Department of IT Convergence, Korea National University of Transportation, Chungju, 380-702 (Korea, Republic of); Park, Sung Young, E-mail: parkchem@ut.ac.kr [Department of Chemical and Biological Engineering, Korea National University of Transportation, Chungju, 380-702 (Korea, Republic of); Department of IT Convergence, Korea National University of Transportation, Chungju, 380-702 (Korea, Republic of)

    2014-09-15

    Graphical abstract: Dual responsive surface with highly fouling resistance with the formation of a pH-dependent benzoic imine and redox-sensitive disulfide bond has been developed using a catechol/benzoic acid conjugated polymer and disulfide containing amine end-capped Pluronic. - Highlights: • Stimuli-responsive antifouling surface was prepared by layer-by-layer method. • The surface contact angle showed responsive behavior via pH and redox environments. • Simply coated polymer completely prevented cell adhesion onto surfaces. - Abstract: A dual environmentally responsive polymer with a highly fouling-resistant surface has been developed using poly[(hydroxyethyl methacrylate-g-benzoic acid)-co-(dimethylaminoethyl methacrylate-g-2-chloro-3′, 4′-dihydroxyacetophenone)] [poly[(HEMA-BA)-co-(DMAEMA-CCDP)], P1] as a coating material. The redox-sensitive disulfide containing amine end-capped Pluronic [(Plu-S-S-NH{sub 2}), P2] was then introduced over the P1 surface via the formation of a pH-dependent benzoic imine bond, where the polyethylene glycol (PEG) acts as an antifouling agent. The successful adhesion of P1 and the deposition of P2 onto the P1-coated substrate were ascertained with X-ray photoelectron spectroscopy (XPS). In vitro cell adhesion followed by scanning electron microscopy (SEM) indicated an excellent antifouling nature of the P2 layer. Consequently, the reattachment of Hela cells was strongly observed when P2 layered on P1-coated substrates (P1–P2) was pretreated at lower pH and high redox conditions. The P1–P2 bilayer-coated substrate has exhibited a great advantage in its effective antifouling behaviors with well-tuned cell attachment and detachment.

  7. Total Phosphorus in Surface Water (Future)

    Data.gov (United States)

    U.S. Environmental Protection Agency — Excess phosphorus in surface water can result in eutrophication. TOTALPFuture is reported in kilograms/hectare/year. More information about these resources,...

  8. Surface processing using water cluster ion beams

    Science.gov (United States)

    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.

  9. Surface processing using water cluster ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Takaoka, Gikan H., E-mail: gtakaoka@kuee.kyoto-u.ac.jp [Photonics and Electronics Science and Engineering Center, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510 (Japan); Ryuto, Hiromichi; Takeuchi, Mitsuaki; Ichihashi, Gaku [Photonics and Electronics Science and Engineering Center, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510 (Japan)

    2013-07-15

    Vaporized water clusters were produced by an adiabatic expansion phenomenon, and various substrates such as Si(1 0 0), SiO{sub 2}, 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.

  10. Exit Creek Water Surface Survey, June 2013

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset consists of survey data from a longitudinal profile of water surface surveyed June 23-24, 2013 at Exit Creek, a stream draining Exit Glacier in Kenai...

  11. US Forest Service Surface Drinking Water Importance

    Data.gov (United States)

    US Forest Service, Department of Agriculture — A map service on the www depicting watershed indexes to help identify areas of interest for protecting surface drinking water quality. The dataset depicted in this...

  12. Total Nitrogen in Surface Water (Future)

    Data.gov (United States)

    U.S. Environmental Protection Agency — Excess nitrogen in surface water can result in eutrophication. TOTALNFuture is reported in kilograms/hectare/year. More information about these resources, including...

  13. Surface Waters Information Management System (SWIMS)

    Data.gov (United States)

    Kansas Data Access and Support Center — The Surface Waters Information Management System (SWIMS) has been designed to meet multi-agency hydrologic database needs for Kansas. The SWIMS project was supported...

  14. Water desorption from nanostructured graphite surfaces.

    Science.gov (United States)

    Clemens, Anna; Hellberg, Lars; Grönbeck, Henrik; Chakarov, Dinko

    2013-12-21

    Water interaction with nanostructured graphite surfaces is strongly dependent on the surface morphology. In this work, temperature programmed desorption (TPD) in combination with quadrupole mass spectrometry (QMS) has been used to study water ice desorption from a nanostructured graphite surface. This model surface was fabricated by hole-mask colloidal lithography (HCL) along with oxygen plasma etching and consists of a rough carbon surface covered by well defined structures of highly oriented pyrolytic graphite (HOPG). The results are compared with those from pristine HOPG and a rough (oxygen plasma etched) carbon surface without graphite nanostructures. The samples were characterized using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The TPD experiments were conducted for H2O coverages obtained after exposures between 0.2 and 55 langmuir (L) and reveal a complex desorption behaviour. The spectra from the nanostructured surface show additional, coverage dependent desorption peaks. They are assigned to water bound in two-dimensional (2D) and three-dimensional (3D) hydrogen-bonded networks, defect-bound water, and to water intercalated into the graphite structures. The intercalation is more pronounced for the nanostructured graphite surface in comparison to HOPG surfaces because of a higher concentration of intersheet openings. From the TPD spectra, the desorption energies for water bound in 2D and 3D (multilayer) networks were determined to be 0.32 ± 0.06 and 0.41 ± 0.03 eV per molecule, respectively. An upper limit for the desorption energy for defect-bound water was estimated to be 1 eV per molecule.

  15. Polyfluorinated chemicals in European surface waters, ground- and drinking waters

    NARCIS (Netherlands)

    Eschauzier, C.; de Voogt, P.; Brauch, H.-J.; Lange, F.T.; Knepper, T.P.; Lange, F.T.

    2012-01-01

    Polyfluorinated chemicals (PFCs), especially short chain fluorinated alkyl sulfonates and carboxylates, are ubiquitously found in the environment. This chapter aims at giving an overview of PFC concentrations found in European surface, ground- and drinking waters and their behavior during convention

  16. Polyfluorinated chemicals in European surface waters, ground- and drinking waters

    NARCIS (Netherlands)

    Eschauzier, C.; de Voogt, P.; Brauch, H.-J.; Lange, F.T.; Knepper, T.P.; Lange, F.T.

    2012-01-01

    Polyfluorinated chemicals (PFCs), especially short chain fluorinated alkyl sulfonates and carboxylates, are ubiquitously found in the environment. This chapter aims at giving an overview of PFC concentrations found in European surface, ground- and drinking waters and their behavior during

  17. Fluidized-bed denitrification for mine waters. Part I: low pH and temperature operation.

    Science.gov (United States)

    Papirio, S; Ylinen, A; Zou, G; Peltola, M; Esposito, G; Puhakka, J A

    2014-06-01

    Mining often leads to nitrate and metal contamination of groundwater and water bodies. Denitrification of acidic water was investigated in two up-flow fluidized-bed reactors (FBR) and using batch assays. Bacterial communities were enriched on ethanol plus nitrate in the FBRs. Initially, the effects of temperature, low-pH and ethanol/nitrate on denitrification were revealed. Batch assays showed that pH 4.8 was inhibitory to denitrification, whereas FBR characteristics permitted denitrification even at feed pH of 2.5 and at 7-8 °C. Nitrate and ethanol were removed and the feed pH was neutralized, provided that ethanol was supplied in excess to nitrate. Subsequently, Fe(II) and Cu impact on denitrification was investigated within batch tests at pH 7. Iron supplementation up to 100 mg/L resulted in iron oxidation and soluble concentrations ranging from 0.4 to 1.6 mg/L that stimulated denitrification. On the contrary, 0.7 mg/L of soluble Cu significantly slowed denitrification down resulting in about 45 % of inhibition in the first 8 h. Polymerase chain reaction-denaturant gradient gel electrophoresis demonstrated the co-existence of different denitrifying microbial consortia in FBRs. Dechloromonas denitrificans and Hydrogenophaga caeni were present in both FBRs and mainly responsible for nitrate reduction.

  18. Effect of pH on surface energy of glass and Teflon and theoretical prediction of Staphylococcus aureus adhesion

    Energy Technology Data Exchange (ETDEWEB)

    Hamadi, F. [Equipe de recherche: Microbiologie et biochimie appliquee a l' agroalimentaire, l' environnement et la sante. Faculte de Sciences et Techniques, B. P 523, Beni, Mellal (Morocco); Latrache, H., E-mail: latracheh@yahoo.fr [Equipe de recherche: Microbiologie et biochimie appliquee a l' agroalimentaire, l' environnement et la sante. Faculte de Sciences et Techniques, B. P 523, Beni, Mellal (Morocco); Zekraoui, M. [Equipe de recherche: Genie industriel, agroalimentaire et environnement. Faculte de Sciences et Techniques, B. P 523, Beni, Mellal (Morocco); Ellouali, M. [Equipe de recherche: Microbiologie et biochimie appliquee a l' agroalimentaire, l' environnement et la sante. Faculte de Sciences et Techniques, B. P 523, Beni, Mellal (Morocco); Bengourram, J. [Equipe de recherche: Genie industriel, agroalimentaire et environnement. Faculte de Sciences et Techniques, B. P 523, Beni, Mellal (Morocco)

    2009-05-05

    The surface energy of glass and Teflon at various pH values was examined. Contact angle was used to determine physico-chemical substratum properties. The surface energy of both substratums including, hydrophobicity, and electron donor/electron acceptor (Lewis acid-base properties) were found to depend on pH of contact solution. The maximum of hydrophobicity (higher negative value of {Delta}G{sub iwi}) was obtained at pH 11 and pH 6.5 for glass and Teflon respectively. The electron donor property was higher at pH 5 and pH 3 for glass and Teflon respectively. Moreover, prediction of Staphylococcus aureus adhesion on both substratums was estimated by calculating the total interaction free energy ({Delta}G{sup Tot}). Based on the value of {Delta}G{sup Tot}, S. aureus should adhere to glass at pH 2, pH 3 and pH 11 with the maximal adhesion obtained at pH 3 and pH 11. For Teflon, regardless of pH values, S. aureus should be able to attach on this substratum with the high adhesion level at pH 5. The relation between surface energy of substratum and the total interaction free energy was also examined. Based on this relation and the value of the components of total interaction free energy, we show that adhesion to glass could be governed by both short range forces (Lewis acid-bases forces) and by long range forces (van der Waals forces) and the adhesion to Teflon could be mediated only by the short range forces.

  19. Responsive Grafted Polymer Layers: the role of pH, temperature and surface geometry

    Science.gov (United States)

    Szleifer, Igal

    2011-03-01

    The competition between chemical equilibrium, e.g. protonation, and physical interactions determines the molecular organization and functionality in biological and synthetic systems. Charge regulation by displacement of acid-base equilibrium induced by changes in the local environment provides for a feedback mechanism that controls the balance between electrostatic, van der Waals, steric interactions and molecular organization. What are the mechanisms that determine the interplay between all these different factors? In this talk I will describe a molecular theory to address this question. In particular, the theory will be used to study the structural and thermodynamic properties of end-grafted polyacids with hydrophobic backbones. The molecular theory explicitly includes the size, shape, conformations, charge and charge distribution of all the molecular species in the system and incorporates excluded volume, van der Walls and electrostatic interactions coupled with acid-base equilibrium. On planar surfaces, the theory predicts the formation of surface micelles with morphologies that depend upon the bulk pH, solution ionic strength, temperature and surface coverage. The self assembled aggregates, present domains of varying local pH that is very different from that of the bulk solution. We show that a qualitatively new form of local organization arises that is only found when there is explicit coupling between charge regulation and physical interactions. The different morphologies can be manipulated by changing the bulk solution conditions and they provide for local domains with controlled charge and pH with large gradients with a characteristic size of a few nanometers. Following this we will discuss how ion conductivity in nanopores functionalized with polybases changes as a function of solution pH. The predictions of the theory are in quantitative agreement with experiments and they provide a physical explanation of the interplay between molecular organization and

  20. Calcification of the cold-water coral Lophelia pertusa, under ambient and reduced pH

    Directory of Open Access Journals (Sweden)

    J.-P. Gattuso

    2009-08-01

    Full Text Available The cold-water coral Lophelia pertusa is one of the few species able to build reef-like structures and a 3-dimensional coral framework in the deep oceans. Furthermore, deep cold-water coral bioherms may be among the first marine ecosystems to be affected by ocean acidification. Colonies of L. pertusa were collected during a cruise in 2006 to cold-water coral bioherms of the Mingulay reef complex (Hebrides, North Atlantic. Shortly after sample collection onboard these corals were labelled with calcium-45. The same experimental approach was used to assess calcification rates and how those changed due to reduced pH during a cruise to the Skagerrak (North Sea in 2007. The highest calcification rates were found in youngest polyps with up to 1% d−1 new skeletal growth and average rates of 0.11±0.02% d−1±S.E.. Lowering pH by 0.15 and 0.3 units relative to the ambient level resulted in calcification being reduced by 30 and 56%. Lower pH reduced calcification more in fast growing, young polyps (59% reduction than in older polyps (40% reduction. Thus skeletal growth of young and fast calcifying corallites suffered more from ocean acidification. Nevertheless, L. pertusa exhibited positive net calcification (as measured by 45Ca incorporation even at an aragonite saturation state (Ωa below 1.

  1. A noise-resistant ADSA-PH algorithm for superhydrophobic surface's static contact angle evaluation

    Science.gov (United States)

    Xu, Z. N.

    2017-03-01

    The blur around the contact points significantly decreases the evaluated static contact angle for superhydrophobic surface which is clearly presented in the paper. To improve the accuracy in the evaluated static contact angle for superhydrophobic surface, an accurate static contact angle algorithm, namely ADSA-PH (axisymmetric drop shape analysis-profile and height), is proposed. It discards the extracted drop edge points close to the contact points and makes use of the residual points and the drop height to determine the static contact angle. The contact angle errors caused by the blur close to the contact points are significantly reduced. The classical ADSA-P algorithm, the modified selected-plane method and the proposed algorithm are used to evaluate static contact angle. The results validate the proposed algorithm. The accuracy in the evaluated contact angle increases with increasing image resolution. To reduce the error caused by a limitation of image resolution, the minimum allowable image resolutions are presented.

  2. Influence of ph on corrosion control of carbon steel by peroxide injection in sour water

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, Martins Magda; Baptista, Walmar; Joia, Carlos Jose Bandeira de Mello [PROTEMP - PETROBRAS/CENPES, Cidade Universitaria, Quadra 7, Rio de Janeiro, CEP 21949-900 (Brazil); Ponciano, Gomes Jose Antonio da Cunha [Departamento de Engenharia Metalurgica e de Materiais-COPPE/UFRJ, Cidade Universitaria, Rio de Janeiro (Brazil)

    2004-07-01

    Sour hydrogen damage is considered the most important corrosive process in the light-ends recovery section of Fluid Catalytic Cracking Units (FCCU). Corrosion in this condition is due to heavy gas oil that originates great amount of contaminants, such as H{sub 2}S, NH{sub 3} and HCN. Hydrogen absorption is promoted by the presence of free cyanides in the environment. The attenuation of this process requires the use of some inhibitors, such as oxygen, hydrogen peroxide (H{sub 2}O{sub 2}) or commercial polysulfides. The effect of these compounds is to neutralize free cyanides (CN{sup -}) into thio-sulfides (SCN{sup -}). When peroxide injection is selected, cyanide concentration in sour water has been used as key parameter to start the peroxide introduction. However, the importance of pH in this system has been pointed out by many authors. The aim of this work is to investigate the influence of pH when peroxide injection is carried out in less alkaline conditions of sour water. Electrochemical techniques - like anodic polarization and hydrogen permeation tests - and weight loss measurements were used to evaluate the effectiveness of corrosion control of carbon steel. It was concluded that at pH 7.5 peroxide injection can drive to an increment of the corrosion rate. Besides that, it was concluded that hydrogen permeation into the metal is promoted. Both detrimental effects were due to elemental sulfur generation in this pH range. The adoption of pH as a key parameter for peroxide injection is then suggested. (authors)

  3. Stable water layers on solid surfaces.

    Science.gov (United States)

    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.

  4. pH induced polychromatic UV treatment for the removal of a mixture of SMX, OTC and CIP from water

    Energy Technology Data Exchange (ETDEWEB)

    Avisar, D., E-mail: droravi@post.tau.ac.il [Hydro-chemistry Laboratory, Geography and the Environment, Tel Aviv University, Tel Aviv 69978 (Israel); Lester, Y. [Hydro-chemistry Laboratory, Geography and the Environment, Tel Aviv University, Tel Aviv 69978 (Israel); School of Mechanical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978 (Israel); Mamane, H. [School of Mechanical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978 (Israel)

    2010-03-15

    Water and wastewater effluents contain a vast range of chemicals in mixtures that have different chemical structures and characteristics. This study presents a treatment technology for the removal of mixtures of antibiotic residues (sulfamethoxazole (SMX), oxtetracycline (OTC) and ciprofloxacin (CIP)) from contaminated water. The treatment combines pH modification of the water to an optimal value, followed by a photolytic treatment using direct polychromatic ultraviolet (UV) irradiation by medium pressure UV lamp. The pH adjustment of the treated water leads to structural modifications of the pollutant's molecule thus may enhance direct photolysis by UV light. Results showed that an increase of water pH from 5 to 7 leads to a decrease in degradation rate of SMX and an increase in degradation rate of OTC and CIP, when studied separately and not in a mixture. Thus, the optimal pH values for UV photodegradation in a mixture, involve initial photolysis at pH 5 and then gradually changing the pH from 5 to 7 during the UV exposure. For example, this resulted in 99% degradation of SMX at pH 5 and enhanced degradation of OTC and CIP from 54% and 26% to 91% and 96% respectively when pH was increased from 5 to 7. Thus the pH induced photolytic treatment has a potential in improving treatment of antibiotics in mixtures.

  5. pH induced polychromatic UV treatment for the removal of a mixture of SMX, OTC and CIP from water.

    Science.gov (United States)

    Avisar, D; Lester, Y; Mamane, H

    2010-03-15

    Water and wastewater effluents contain a vast range of chemicals in mixtures that have different chemical structures and characteristics. This study presents a treatment technology for the removal of mixtures of antibiotic residues (sulfamethoxazole (SMX), oxytetracycline (OTC) and ciprofloxacin (CIP)) from contaminated water. The treatment combines pH modification of the water to an optimal value, followed by a photolytic treatment using direct polychromatic ultraviolet (UV) irradiation by medium pressure UV lamp. The pH adjustment of the treated water leads to structural modifications of the pollutant's molecule thus may enhance direct photolysis by UV light. Results showed that an increase of water pH from 5 to 7 leads to a decrease in degradation rate of SMX and an increase in degradation rate of OTC and CIP, when studied separately and not in a mixture. Thus, the optimal pH values for UV photodegradation in a mixture, involve initial photolysis at pH 5 and then gradually changing the pH from 5 to 7 during the UV exposure. For example, this resulted in 99% degradation of SMX at pH 5 and enhanced degradation of OTC and CIP from 54% and 26% to 91% and 96% respectively when pH was increased from 5 to 7. Thus the pH induced photolytic treatment has a potential in improving treatment of antibiotics in mixtures. (c) 2009 Elsevier B.V. All rights reserved.

  6. Origins of high pH mineral waters from ultramafic rocks, Central Portugal

    Energy Technology Data Exchange (ETDEWEB)

    Marques, Jose M. [Instituto Superior Tecnico, Av. Rovisco Pais, 1049-001, Lisboa (Portugal)], E-mail: jose.marques@ist.ult.pt; Carreira, Paula M. [Instituto Tecnologico e Nuclear, Estrada Nacional No 10, 2686-953 Sacavem (Portugal); Carvalho, Maria Rosario [Departamento de Geologia, Faculdade de Ciencias, Universidade de Lisboa, Ed. C6, 3oP, Campo Grande, 1749-016 Lisboa (Portugal); Matias, Maria J. [Instituto Superior Tecnico, Av. Rovisco Pais, 1049-001, Lisboa (Portugal); Goff, Fraser E. [Earth and Planetary Sciences Department MSCO3-2040, University of New Mexico, Albuquerque, New Mexico 87131-000 (United States); Basto, Maria J.; Graca, Rui C.; Aires-Barros, Luis [Instituto Superior Tecnico, Av. Rovisco Pais, 1049-001, Lisboa (Portugal); Rocha, Luis [Junta de Freguesia, Av. da Libertacao, 45-D, 7460-002, Cabeco de Vide (Portugal)

    2008-12-15

    This paper reviews the geochemical, isotopic ({sup 2}H, {sup 18}O, {sup 13}C, {sup 3}H and {sup 14}C) and numerical modelling approaches to evaluate possible geological sources of the high pH (11.5)/Na-Cl/Ca-OH mineral waters from the Cabeco de Vide region (Central-Portugal). Water-rock interaction studies have greatly contributed to a conceptual hydrogeological circulation model of the Cabeco de Vide mineral waters, which was corroborated by numerical modelling approaches. The local shallow groundwaters belong to the Mg-HCO{sub 3} type, and are derived by interaction with the local serpentinized rocks. At depth, these type waters evolve into the high pH/Na-Cl/Ca-OH mineral waters of Cabeco de Vide spas, issuing from the intrusive contact between mafic/ultramafic rocks and an older carbonate sequence. The Cabeco de Vide mineral waters are supersaturated with respect to serpentine indicating that they may cause serpentinization. Magnesium silicate phases (brucite and serpentine) seem to control Mg concentrations in Cabeco de Vide mineral waters. Similar {delta}{sup 2}H and {delta}{sup 18}O suggest a common meteoric origin and that the Mg-HCO{sub 3} type waters have evolved towards Cabeco de Vide mineral waters. The reaction path simulations show that the progressive evolution of the Ca-HCO{sub 3} to Mg-HCO{sub 3} waters can be attributed to the interaction of meteoric waters with serpentinites. The sequential dissolution at CO{sub 2} (g) closed system conditions leads to the precipitation of calcite, magnesite, amorphous silica, chrysotile and brucite, indicating that the waters would be responsible for the serpentinization of fresh ultramafic rocks (dunites) present at depth. The apparent age of Cabeco de Vide mineral waters was determined as 2790 {+-} 40 a BP, on the basis of {sup 14}C and {sup 13}C values, which is in agreement with the {sup 3}H concentrations being below the detection limit.

  7. Single step, pH induced gold nanoparticle chain formation in lecithin/water system.

    Science.gov (United States)

    Sharma, Damyanti

    2013-07-01

    Gold nanoparticle (AuNP) chains have been formed by a single step method in a lecithin/water system where lecithin itself plays the role of a reductant and a template for AuNP chain formation. Two preparative strategies were explored: (1) evaporating lecithin solution with aqueous gold chloride (HAuCl4) at different pHs and (2) dispersing lecithin vesicles in aqueous HAuCl4 solutions of various pHs in the range of 2.5-11.3. In method 1, at initial pH 2.5, 20-50 nm AuNPs are found attached to lecithin vesicles. When pH is raised to 5.5 there are no vesicles present and 20 nm monodisperse particles are found aggregating. Chain formation of fine nanoparticles (3-5 nm) is observed from neutral to basic pH, between 6.5-10.3 The chains formed are hundreds of nanometers to micrometer long and are usually 2-3 nanoparticles wide. On further increasing pH to 11.3, particles form disk-like or raft-like structures. When method (ii) was used a little chain formation was observed. Most of the nanoparticles formed were found either sitting together as raft like structures or scattered on lecithin structures. Copyright © 2013 Elsevier B.V. All rights reserved.

  8. Radiolysis of water with aluminum oxide surfaces

    Science.gov (United States)

    Reiff, Sarah C.; LaVerne, Jay A.

    2017-02-01

    Aluminum oxide, Al2O3, nanoparticles with water were irradiated with γ-rays and 5 MeV He ions followed by the determination of the production of molecular hydrogen, H2, and characterization of changes in the particle surface. Surface analysis techniques included: diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), nitrogen absorption with the Brunauer - Emmett - Teller (BET) methodology for surface area determination, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Production of H2 by γ-ray radiolysis was determined for samples with adsorbed water and for Al2O3 - water slurries. For Al2O3 samples with adsorbed water, the radiation chemical yield of H2 was measured as 80±20 molecules/100 eV (1 molecule/100 eV=1.04×10-7 mol/J). The yield of H2 was observed to decrease as the amount of water present in the Al2O3 - water slurries increased. Surface studies indicated that the α-phase Al2O3 samples changed phase following irradiation by He ions, and that the oxyhydroxide layer, present on the pristine sample, is removed by γ-ray and He ion irradiation.

  9. Water vapor interactions with polycrystalline titanium surfaces

    Science.gov (United States)

    Azoulay, A.; Shamir, N.; Volterra, V.; Mintz, M. H.

    1999-02-01

    The initial interactions of water vapor with polycrystalline titanium surfaces were studied at room temperature. Measurements of water vapor surface accumulation were performed in a combined surface analysis system incorporating direct recoils spectrometry (DRS), Auger electron spectroscopy and X-ray photoelectron spectroscopy. The kinetics of accommodation of the water dissociation fragments (H, O and OH) displayed a complex behavior depending not only on the exposure dose but also on the exposure pressure. For a given exposure dose the efficiency of chemisorption increased with increasing exposure pressure. DRS measurements indicated the occurrence of clustered hydroxyl moieties with tilted O-H bonds formed even at very low surface coverage. A model which assumes two parallel routes of chemisorption, by direct collisions (Langmuir type) and by a precursor state is proposed to account for the observed behavior. The oxidation efficiency of water seemed to be much lower than that of oxygen. No Ti 4+ states were detected even at high water exposure values. It is likely that hydroxyl species play an important role in the reduced oxidation efficiency of water.

  10. A Water Rich Mars Surface Mission Scenario

    Science.gov (United States)

    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

  11. Electrolysis of water on (oxidized) metal surfaces

    DEFF Research Database (Denmark)

    Rossmeisl, Jan; Logadottir, Ashildur; Nørskov, Jens Kehlet

    2005-01-01

    directly from the electronic structure calculations. We consider electrodes of Pt(111) and Au(111) in detail and then discuss trends for a series of different metals. We show that the difficult step in the water splitting process is the formation of superoxy-type (OOH) species on the surface...... by the splitting of a water molecule on top an adsorbed oxygen atom. One conclusion is that this is only possible on metal surfaces that are (partly) oxidized. We show that the binding energies of the different intermediates are linearly correlated for a number of metals. In a simple analysis, where the linear...... relations are assumed to be obeyed exactly, this leads to a universal relationship between the catalytic rate and the oxygen binding energy. Finally, we conclude that for systems obeying these relations, there is a limit to how good a water splitting catalyst an oxidized metal surface can become. (c) 2005...

  12. Surface Modification of Water Purification Membranes.

    Science.gov (United States)

    Miller, Daniel J; Dreyer, Daniel R; Bielawski, Christopher W; Paul, Donald R; Freeman, Benny D

    2017-04-18

    Polymeric membranes are an energy-efficient means of purifying water, but they suffer from fouling during filtration. Modification of the membrane surface is one route to mitigating membrane fouling, as it helps to maintain high levels of water productivity. Here, a series of common techniques for modification of the membrane surface are reviewed, including surface coating, grafting, and various treatment techniques such as chemical treatment, UV irradiation, and plasma treatment. Historical background on membrane development and surface modification is also provided. Finally, polydopamine, an emerging material that can be easily deposited onto a wide variety of substrates, is discussed within the context of membrane modification. A brief summary of the chemistry of polydopamine, particularly as it may pertain to membrane development, is also described. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. pH and Eh effects on phosphorus fate in constructed wetland's sludge surface deposit.

    Science.gov (United States)

    Kim, Boram; Gautier, Mathieu; Simidoff, Arnaud; Sanglar, Corinne; Chatain, Vincent; Michel, Philippe; Gourdon, Rémy

    2016-12-01

    The objective of the present study was to assess the influence of extreme pH and redox potential (Eh) conditions on phosphorus (P) retention within the surface sludge deposit layer of a vertical flow constructed wetland (VFCW) where phosphorus was captured by FeCl3 injection. Series of 27 successive batch leaching tests were conducted under acidic, alkaline or reductive conditions using a representative sludge sample taken from an 8-year old VFCW plant. Experiments were followed by monitoring the pH and Eh variations and analysing the releases of P and other selected elements into the solutions. The sludge material was also analyzed before and after leaching, using solution (31)P NMR spectroscopy and sequential chemical extractions, in order to evaluate dissolutions of both organic and inorganic P-bearing species and their respective contributions to P release. The correlations between the monitored variables were analyzed and visualized through principal components analyses (PCA). Results showed a very good stability of P retention in the sludge deposit and a relatively good acid-buffering capacity of the sludge, revealing that the risk of accidental P release into the environment would be extremely low during the real plant operation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Surface Water Protection by Productive Buffers

    DEFF Research Database (Denmark)

    Christen, Benjamin

    Vegetated riparian buffer zones are a widely recommended best management practice in agriculture for protecting surface and coastal waters from diffuse nutrient pollution. On the background of the EU funded research project NitroEurope (NEU; www.NitroEurope.eu), this study concentrates...... on the mitigation of nitrogen pollution in surface and groundwater, using riparian buffer zones for biomass production. The objectives are to map suitable areas for buffer implementation across the six NEU study landscapes, model tentative N-loss mitigation, calculate biomass production potential and economic...... designed for local conditions could be a way of protecting water quality attractive to many stakeholders....

  15. Effect of pH Upper Control Limit on Nutrient Solution Component and Water Spinach Growth under Hydroponics

    Directory of Open Access Journals (Sweden)

    Xuzhang Xue

    2015-09-01

    Full Text Available In this study, experiment with four levels of nutrient solution pH control upper limit was conducted to explore the optimal nutrient solution pH management scheme under hydroponics by evaluating the nutrient solution characters i.e., pH, Electric Conductivity (EC, nitrate, soluble phosphorus (soluble-P, water spinach growth and quality. The results showed that the nutrient solution pH was 8.2 and unsuitable for water spinach growth under the treatment with no pH regulation during the experimental period. The pH could be maintained within a reasonable range for water spinach growth by adding nitric acid to nutrient solution. Meanwhile, the availability of cations and soluble-P were improved. The water/nutrition uptake was also promoted. Through nutrient solution pH control, the plant height, leaf number and fresh/dry shoot weight increased by 34.66-55.70%, 12.42-13.66%, 39.18¬-101.72% and 13.78-74.03%, respectively. It indicated that pH regulation could improve water spinach growth, promote allocation of photosynthetic product to shoot and increase the effective yield. The nitrate content of water spinach shoot increased, but which was lower than the critical value of 3000 mg/kg FW. Vitamin C content decreased under the treatment which 6.5 of pH control upper limit was set. There were no significant differences in soluble sugar and crude protein content among the four treatments. Considering the yield and quality of water spinach, the suitable nutrient solution pH control upper limit was 7.0.

  16. How water meets a hydrophobic surface: Reluctantly and with flucuations

    Science.gov (United States)

    Poynor Torigoe, Adele Nichole

    By definition hydrophobic substances hate water. Water placed on a hydrophobic surface will form a drop in order to minimize its contact area. What happens when water is forced into contact with a hydrophobic surface? One theory is that an ultra-thin low density region forms near the surface. This depleted region would have implications in such diverse areas as colloidal self-assembly, and the boundary conditions of fluid flow. However, the literature still remains divided as to whether or not such a depleted region exists. To investigate the existence of this layer, we have employed three surface-sensitive techniques, time-resolved phase-modulated ellipsometry, surface plasmon resonance, and X-ray reflectivity. Both ellipsometry and X-ray reflectivity provide strong evidence for the low-density layer and illuminate unexpected temporal behavior. Using all three techniques, we found surprising fluctuations at the interface with a non-Gaussian distribution and a single characteristic time on the order of tenths of seconds. This information supports the idea that the boundary fluctuates with something akin to capillary waves. We have also investigated the dependence of the static and dynamic properties of the hydrophobic/water interface on variables such as temperature, contact angle, pH, dissolved gasses, and sample quality, among others, in a hope to discover the root of the controversy in the literature. We found that the depletion layer is highly dependent on temperature, contact angle and sample quality. This dependence might explain some of the discrepancies in the literature as different groups often use hydrophobic surfaces with different properties.

  17. Ultra Water Repellent Polypropylene Surfaces with Tunable Water Adhesion.

    Science.gov (United States)

    Zhu, Tang; Cai, Chao; Guo, Jing; Wang, Rong; Zhao, Ning; Xu, Jian

    2017-03-22

    Polypropylene (PP), including isotactic PP (i-PP) and atactic PP (a-PP) with distinct tacticity, is one of the most widely used general plastics. Herein, ultra water repellent PP coatings with tunable adhesion to water were prepared via a simple casting method. The pure i-PP coating shows a hierarchical morphology with micro/nanobinary structures, exhibiting a water contact angle (CA) larger than 150° and a sliding angle less than 5° (for 5 μL water droplet). In contrast, the pure a-PP coating has a less rough morphology with a water contact angle of about 130°, and the water droplets stick on the coating at any tilted angles. For the composite i-PP/a-PP coatings, however, ultra water repellency with CA > 150° but water adhesion tailorable from slippery to sticky can be realized, depending on the contents of a-PP and i-PP. The different wetting behaviors are due to the various microstructures of the composite coatings resulting from the distinct crystallization ability of a-PP and i-PP. Furthermore, the existence of a-PP in the composite coatings enhances the mechanical properties compared to the i-PP coating. The proposed method is feasible to modify various substrates and potential applications in no-loss liquid transportation, slippery surfaces, and patterned superhydrophobic surfaces are demonstrated.

  18. Adsorption behavior of methyl orange onto wheat bran: Role of surface and pH

    Directory of Open Access Journals (Sweden)

    Atef S. Alzaydien

    2015-06-01

    Full Text Available This paper deals with the application of wheat bran (WB, an agricultural by-product, for the adsorption of methyl orange (MO from aqueous solution. The characteristics of WS surface, such as surface functional groups, zero of point charge and conductivity were obtained. The removal of MO onto WB from aqueous solution was investigated by using parameters, such as pH, temperature, adsorbent dose and contact time. A spectrophotometer technique was used for measuring the extent of adsorption. The extent of dye removal decreased with increasing adsorbent dosage and also increased with increasing contact time and temperature. The results revealed that the sorption capacity increases from 12.34 to 19.85 mg/g when the temperature increased from 25 to 55 ﻩC. This suggests that the sorption of MO dye onto WB is endothermic and activated process indicating that the higher temperature is more favorable for the dye sorption. Optimum pH value for dye adsorption was determined to be 4.0. strong pH-dependence of MO adsorption onto WB together with FTIR results indicate to possible involvement of physical forces such as hydrogen bonding, Vander Waals and covalent chemical bonds in the adsorption process. In addition, the adsorption data of MO by WB were applied to Lagergren,s pseudo first-order, pseudo second-order and the rate constants of first-order adsorption (k1 = 1.34x102 min-1 the rate constants of second-order adsorption (k2 = 2.93x10-3 g/mgmin were calculated, respectively.. The results indicate that WB could be employed as a low-cost alternative to other adsorbents in the removal of MO from aqueous solution.

  19. Influence of surface porosity and pH on bacterial adherence to hydroxyapatite and biphasic calcium phosphate bioceramics.

    Science.gov (United States)

    Kinnari, Teemu J; Esteban, Jaime; Martin-de-Hijas, Nieves Z; Sánchez-Muñoz, Orlando; Sánchez-Salcedo, Sandra; Colilla, Montserrat; Vallet-Regí, María; Gomez-Barrena, Enrique

    2009-01-01

    Hydroxyapatite (HA) and biphasic calcium phosphate (BCP) ceramic materials are widely employed as bone substitutes due to their porous and osteoconductive structure. Their porosity and the lowering of surrounding pH as a result of surgical trauma may, however, predispose these materials to bacterial infections. For this reason, the influence of porosity and pH on the adherence of common Gram-positive bacteria to the surfaces of these materials requires investigation. Mercury intrusion porosimetry measurements revealed that the pore size distribution of both bioceramics had, on a logarithmic scale, a sinusoidal frequency distribution ranging from 50 to 300 nm, with a mean pore diameter of 200 nm. Moreover, total porosity was 20 % for HA and 50 % for BCP. Adherence of Staphylococcus aureus and Staphylococcus epidermidis was studied at a physiological pH of 7.4 and at a pH simulating bone infection of 6.8. Moreover, the effect of pH on the zeta potential of HA, BCP and of both staphylococci was evaluated. Results showed that when pH decreased from 7.4 to 6.8, the adherence of both staphylococci to HA and BCP surfaces decreased significantly, although at the same time the negative zeta-potential values of the ceramic surfaces and both bacteria diminished. At both pH values, the number of S. aureus adhered to the HA surface appeared to be lower than that for BCP. A decrease in pH to 6.8 reduced the adherence of both bacterial species (mean 57 %). This study provides evidence that HA and BCP ceramics do not have pores sufficiently large to allow the internalization of staphylococci. Their anti-adherent properties seemed to improve when pH value decreased, suggesting that HA and BCP bioceramics are not compromised upon orthopaedic use.

  20. Flow and coral morphology control coral surface pH: Implications for the effects of ocean acidification

    Directory of Open Access Journals (Sweden)

    Neil C. S. Chan

    2016-02-01

    Full Text Available The future impact of ocean acidification (OA on corals is disputed in part because mathematical models used to predict these impacts do not seem to capture, or offer a framework to adequately explain, the substantial variability in acidification effects observed in empirical studies. The build-up of a diffusive boundary layer (DBL, wherein solute transport is controlled by diffusion, can lead to pronounced differences between the bulk seawater pH, and the actual pH experienced by the organism, a factor rarely considered in mathematical modelling of ocean acidification effects on corals. In the present study, we developed a simple diffusion-reaction-uptake model that was experimentally parameterized based on direct microsensor measurements of coral tissue pH and O2 within the DBL of a branching and a massive coral. The model accurately predicts tissue surface pH for different coral morphologies and under different flow velocities as a function of ambient pH. We show that, for all cases, tissue surface pH is elevated at lower flows, and thus thicker DBLs. The relative effects of OA on coral surface pH was controlled by flow and we show that under low flow velocities tissue surface pH under OA conditions (pHSWS = 7.8 can be equal to the pH under normal conditions (pHSWS = 8.2. We conclude that OA effects on corals in nature will be complex as the degree to which they are controlled by flow appears to be species specific.

  1. Effect of drinking water treatment process parameters on biological removal of manganese from surface water.

    Science.gov (United States)

    Hoyland, Victoria W; Knocke, William R; Falkinham, Joseph O; Pruden, Amy; Singh, Gargi

    2014-12-01

    Soluble manganese (Mn) presents a significant treatment challenge to many water utilities, causing aesthetic and operational concerns. While application of free chlorine to oxidize Mn prior to filtration can be effective, this is not feasible for surface water treatment plants using ozonation followed by biofiltration because it inhibits biological removal of organics. Manganese-oxidizing bacteria (MOB) readily oxidize Mn in groundwater treatment applications, which normally involve pH > 7.0. The purpose of this study was to evaluate the potential for biological Mn removal at the lower pH conditions (6.2-6.3) often employed in enhanced coagulation to optimize organics removal. Four laboratory-scale biofilters were operated over a pH range of 6.3-7.3. The biofilters were able to oxidize Mn at a pH as low as pH 6.3 with greater than 98% Mn removal. Removal of simulated organic ozonation by-products was also greater than 90% in all columns. Stress studies indicated that well-acclimated MOB can withstand variations in Mn concentration (e.g., 0.1-0.2 mg/L), hydraulic loading rate (e.g., 2-4 gpm/ft(2); 1.36 × 10(-3)-2.72 × 10(-3) m/s), and temperature (e.g., 7-22 °C) typically found at surface water treatment plants at least for relatively short (1-2 days) periods of time. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Global modelling of Cryptosporidium in surface water

    Science.gov (United States)

    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

  3. A pH dependent Raman and surface enhanced Raman spectroscopic studies of citrazinic acid aided by theoretical calculations

    Science.gov (United States)

    Sarkar, Sougata; Chowdhury, Joydeep; Dutta, Soumen; Pal, Tarasankar

    2016-12-01

    A pH dependent normal Raman scattering (NRS) and surface enhanced Raman scattering (SERS) spectral patterns of citrazinic acid (CZA), a biologically important molecule, have been investigated. The acid, with different pKa values (~ 4 and ~ 11) for the two different functional groups (-COOH and -OH groups), shows interesting range of color changes (yellow at pH ~ 14 and brown at pH ~ 2) with the variation in solution pH. Thus, depending upon the pH of the medium, CZA molecule can exist in various protonated and/or deprotonated forms. Here we have prescribed the existence different possible forms of CZA at different pH (Forms "C", "H" and "Dprot" at pH ~ 14 and Forms "A", "D", and "P" at pH ~ 2 respectively). The NRS spectra of these solutions and their respective SERS spectra over gold nanoparticles were recorded. The spectra clearly differ in their spectral profiles. For example the SERS spectra recorded with the CZA solution at pH ~ 2 shows blue shift for different bands compared to its NRS window e.g. 406 to 450 cm- 1, 616 to 632 cm- 1, 1332 to 1343 cm- 1 etc. Again, the most enhanced peak at ~ 1548 cm- 1 in NRS while in the SERS window this appears at ~ 1580 cm- 1. Similar observation was also made for CZA at pH ~ 14. For example, the 423 cm- 1 band in the NRS profile experience a blue shift and appears at ~ 447 cm- 1 in the SERS spectrum as well as other bands at ~ 850, ~ 1067 and ~ 1214 cm- 1 in the SERS window are markedly enhanced. It is also worth noting that the SERS spectra at the different pH also differ from each other. These spectral differences indicate the existence of various adsorptive forms of the CZA molecule depending upon the pH of the solution. Therefore based on the experimental findings we propose different possible molecular forms of CZA at different pH (acidic and alkaline) conditions. For example forms 'A', 'D' and 'P' existing in acidic pH (pH ~ 2) and three other deprotonated forms 'C', 'H' and 'Dprot' in alkaline pH (pH ~ 14). The DFT

  4. Lithium content in potable water, surface water, ground water, and mineral water on the territory of Republic of Macedonia

    OpenAIRE

    Vesna Kostik; Biljana Bauer; Zoran Kavrakovski

    2014-01-01

    The aim of this study was to determine lithium concentration in potable water, surface water, ground, and mineral water on the territory of the Republic of Macedonia. Water samples were collected from water bodies such as multiple public water supply systems located in 13 cities, wells boreholes located in 12 areas, lakes and rivers located in three different areas. Determination of lithium concentration in potable water, surface water was performed by the technique of inductively coupl...

  5. Influence of Soft Drinks with Low pH on Different Ni-Ti Orthodontic Archwire Surface Patterns

    Science.gov (United States)

    Abalos, C.; Paul, A.; Mendoza, A.; Solano, E.; Palazon, C.; Gil, F. J.

    2013-03-01

    The aim of this study was to determine the influence of soft drinks on the surface of Ni-Ti archwires and their corrosion behavior. Archwires with different patterns (smooth, scratch, dimple, and crack) were selected and characterized by scanning electron microscopy and laser confocal microscopy. Immersion tests were performed in artificial saliva (pH 6.7) with a soft drink with a pH of 2.5 for 28 days. The results showed an increase in the surface defects and/or roughness of the dimple, crack and scratch patterns with the immersion times, and a decrease in corrosion resistance. A relationship between the surface pattern and the extent of the corrosion in Ni-Ti archwires with soft drinks at low pH has been demonstrated. Pattern should be taken into account in future studies, and manufacturing processes that produce surface defects (especially cracks) should be avoided.

  6. Thermodynamic properties of water solvating biomolecular surfaces

    Science.gov (United States)

    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.

  7. Binding of chloroquine to ionic micelles: Effect of pH and micellar surface charge

    Energy Technology Data Exchange (ETDEWEB)

    Souza Santos, Marcela de, E-mail: marcelafarmausp77@gmail.com [Departamento de Física e Química, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Avenida do Café, s/n, Ribeirão Preto, São Paulo 14040-903 (Brazil); Perpétua Freire de Morais Del Lama, Maria, E-mail: mpemdel@fcfrp.usp.br [Departamento de Física e Química, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Avenida do Café, s/n, Ribeirão Preto, São Paulo 14040-903 (Brazil); Instituto Nacional de Ciência e Tecnologia de Bioanalítica, Departamento de Química Analítica, Universidade Estadual de Campinas, Cidade Universitária Zeferino Vaz, s/n, Campinas, São Paulo 13083-970 (Brazil); Siuiti Ito, Amando, E-mail: amandosi@ffclrp.usp.br [Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Avenida Bandeirantes, 3900, Ribeirão Preto, São Paulo 14040-901 (Brazil); and others

    2014-03-15

    The pharmacological action of chloroquine relies on its ability to cross biological membranes in order to accumulate inside lysosomes. The present work aimed at understanding the basis for the interaction between different chloroquine species and ionic micelles of opposite charges, the latter used as a simple membrane model. The sensitivity of absorbance and fluorescence of chloroquine to changes in its local environment was used to probe its interaction with cetyltrimethylammonium micelles presenting bromide (CTAB) and sulfate (CTAS) as counterions, in addition to dodecyl sulfate micelles bearing sodium (SDS) and tetramethylammonium (TMADS) counterions. Counterion exchange was shown to have little effect on drug–micelle interaction. Chloroquine first dissociation constant (pKa{sub 1}) shifted to opposite directions when anionic and cationic micelles were compared. Chloroquine binding constants (K{sub b}) revealed that electrostatic forces mediate charged drug–micelle association, whereas hydrophobic interactions allowed neutral chloroquine to associate with anionic and cationic micelles. Fluorescence quenching studies indicated that monoprotonated chloroquine is inserted deeper into the micelle surface of anionic micelles than its neutral form, the latter being less exposed to the aqueous phase when associated with cationic over anionic assemblies. The findings provide further evidence that chloroquine–micelle interaction is driven by a tight interplay between the drug form and the micellar surface charge, which can have a major effect on the drug biological activity. -- Highlights: • Chloroquine (CQ) pKa{sub 1} increased for SDS micelles and decreased for CTAB micelles. • CQ is solubilized to the surface of both CTAB and SDS micelles. • Monoprotonated CQ is buried deeper into SDS micelles than neutral CQ. • Neutral CQ is less exposed to aqueous phase in CTAB over SDS micelles. • Local pH and micellar surface charge mediate interaction of CQ with

  8. Impinging Water Droplets on Inclined Glass Surfaces.

    Energy Technology Data Exchange (ETDEWEB)

    Armijo, Kenneth Miguel; Lance, Blake; Ho, Clifford K.

    2017-09-01

    Multiphase computational models and tests of falling water droplets on inclined glass surfaces were developed to investigate the physics of impingement and potential of these droplets to self-clean glass surfaces for photovoltaic modules and heliostats. A multiphase volume-of-fluid model was developed in ANSYS Fluent to simulate the impinging droplets. The simulations considered different droplet sizes (1 mm and 3 mm), tilt angles (0deg, 10deg, and 45deg), droplet velocities (1 m/s and 3 m/s), and wetting characteristics (wetting=47deg contact angle and non-wetting = 93deg contact angle). Results showed that the spread factor (maximum droplet diameter during impact divided by the initial droplet diameter) decreased with increasing inclination angle due to the reduced normal force on the surface. The hydrophilic surface yielded greater spread factors than the hydrophobic surface in all cases. With regard to impact forces, the greater surface tilt angles yielded lower normal forces, but higher shear forces. Experiments showed that the experimentally observed spread factor (maximum droplet diameter during impact divided by the initial droplet diameter) was significantly larger than the simulated spread factor. Observed spread factors were on the order of 5 - 6 for droplet velocities of %7E3 m/s, whereas the simulated spread factors were on the order of 2. Droplets were observed to be mobile following impact only for the cases with 45deg tilt angle, which matched the simulations. An interesting phenomenon that was observed was that shortly after being released from the nozzle, the water droplet oscillated (like a trampoline) due to the "snapback" caused by the surface tension of the water droplet being released from the nozzle. This oscillation impacted the velocity immediately after the release. Future work should evaluate the impact of parameters such as tilt angle and surface wettability on the impact of particle/soiling uptake and removal to investigate ways that

  9. Surface water - groundwater interactions at different spatial and temporal scales

    DEFF Research Database (Denmark)

    Sebök, Éva

    in lowland catchments, mainly exploring and assessing Distributed Temperature Sensing (DTS) which by detecting variability in temperatures at the Sediment-Water Interface (SWI) can indirectly map variability in groundwater discharge at several spatial and temporal scales. On the small-scale (...As there is a growing demand for the protection and optimal management of both the surface water and groundwater resources, the understanding of their exchange processes is of great importance. This PhD study aimed at describing the natural spatial and temporal variability of these interactions...... detected large spatial variability in SWI temperatures with scattered high-discharge sites in a stream and also in a lake where discharge fluxes were estimated by vertical temperature profiles and seepage meter measurements. On the kilometre scale DTS indicated less spatial variability in streambed...

  10. Electrolyte engineering toward efficient water splitting at mild pH

    KAUST Repository

    Shinagawa, Tatsuya

    2017-08-28

    The development of processes for the conversion of H2O/CO2 driven by electricity generated in renewable manners is essential to achieve sustainable energy and chemical cycles, in which the electrocatalytic oxygen evolution reaction (OER) is one of the bottlenecks. In this contribution, the influences of the electrolyte molarity and identity on OER at alkaline to neutral pH were investigated at an appreciable current density of ~10 mA cm-2, revealing (1) the clear boundary of reactant switching between H2O/OH- due to the diffusion limitation of OH- and (2) the substantial contribution of the mass transport of the buffered species in buffered mild pH conditions. These findings propose a strategy of electrolyte engineering: tuning the electrolyte properties to maximize the mass-transport flux. The concept was successfully demonstrated for OER as well as overall water electrolysis in buffered mild pH conditions, shedding light on the development of practical solar fuel production systems.

  11. Influence of temperature, pH and water activity on "in vitro" inhibition of Penicillium glabrum (Wehmer) Westling by yeasts.

    Science.gov (United States)

    Sinigaglia, M; Corbo, M R; Ciccarone, C

    1998-08-01

    Four different yeast species (Metschnikowia pulcherrima, Saccharomycopsis vini, Kluyveromyces marxianus, Cryptococcus albidus), isolated from surface of grapes, were evaluated for biocontrol potential against Penicillium glabrum. In order to investigate the influence of temperature, pH, water activity and yeast cell concentration on Penicillium glabrum inhibition, the individual effects and the interaction of these factors were analyzed by means of a Central Composite Design (CCD). All yeast species tested showed antagonistic effects which were more pronounced at high cell concentrations. The other variables affected the antagonistic effect differentially depending on the yeast species. Results of the experimental design showed that the selective success of a competitive microflora is under environmental control; moreover, when microbial cells are subjected to multiple factors, the effects and the reciprocal interactions of the individual variables cannot be independently evaluated.

  12. Water at surfaces with tunable surface chemistries and the chiral imprint of water around DNA

    Science.gov (United States)

    Petersen, Poul

    Aqueous interfaces are ubiquitous in atmospheric chemistry and biological systems but are notoriously hard to probe experimentally. Surface-specific vibrational spectroscopy offers an avenue to directly probe the vibrational modes of the water OH stretching band but this method is challenging to implement to buried surfaces. Here we present results from sum-frequency generation (SFG) spectroscopy probing the buried interface between a functionalized surface and aqueous solutions. Studying such buried surfaces offers the advantage of being able to systematically tune the surface chemistry using self-assembled monolayers, i.e. the hydrophobic and hydrophilic character, and examine the effect on the interfacial water. In addition to water at these controlled surfaces, we have initiated studying water at biological surfaces. This includes the solvation structure around DNA. X-ray experiments at cryogenic temperatures have found crystallographic water in the minor grove of DNA giving rise to the notion of a spine of hydration surrounding DNA. Such structured water should exhibit a chiral structure adapted from DNA. We investigate if such a chiral water structure exist around DNA at room temperature using chiral SFG. This work was supported by the National Science Foundation under a NSF CAREER Grant (CHE-1151079).

  13. A Water Rich Mars Surface Mission Scenario

    Science.gov (United States)

    Hoffman, Stephen J.; Andrews, Alida; Joosten, B. Kent; Watts, Kevin

    2017-01-01

    In an on-going effort to make human Mars missions more affordable and sustainable, NASA continues to investigate the innovative leveraging of technological advances in conjunction with the use of accessible Martian resources directly applicable to these missions. One of the resources with the broadest utility for human missions is water. Many past studies of human Mars missions assumed a complete lack of water derivable from local sources. However, recent advances in our understanding of the Martian environment provides growing evidence that Mars may be more "water rich" than previously suspected. This is based on data indicating that substantial quantities of water are mixed with surface regolith, bound in minerals located at or near the surface, and buried in large glacier-like forms. This paper describes an assessment of what could be done in a "water rich" human Mars mission scenario. A description of what is meant by "water rich" in this context is provided, including a quantification of the water that would be used by crews in this scenario. The different types of potential feedstock that could be used to generate these quantities of water are described, drawing on the most recently available assessments of data being returned from Mars. This paper specifically focuses on sources that appear to be buried quantities of water ice. (An assessment of other potential feedstock materials is documented in another paper.) Technologies and processes currently used in terrestrial Polar Regions are reviewed. One process with a long history of use on Earth and with potential application on Mars - the Rodriguez Well - is described and results of an analysis simulating the performance of such a well on Mars are presented. These results indicate that a Rodriguez Well capable of producing the quantities of water identified for a "water rich" human mission are within the capabilities assumed to be available on the Martian surface, as envisioned in other comparable Evolvable

  14. Influence of temperature, water activity and pH on growth of some xerophilic fungi.

    Science.gov (United States)

    Gock, Melissa A; Hocking, Ailsa D; Pitt, John I; Poulos, Peter G

    2003-02-25

    The combined effects of water activity (aw), pH and temperature on the germination and growth of seven xerophilic fungi important in the spoilage of baked goods and confectionery were examined. Eurotium rubrum, E. repens, Wallemia sebi, Aspergillus penicillioides, Penicillium roqueforti, Chrysosporium xerophilum and Xeromyces bisporus were grown at 25, 30 and 37 degrees C on media with pH values of 4.5, 5.5, 6.5 and 7.5 and a range of water activities (aw) from 0.92 to 0.70. The aw of the media was controlled with a mixture of equal parts of glucose and fructose. Temperature affected the minimum aw for germination for most species. For example, P. roqueforti germinated at 0.82 aw at 25 degrees C, 0.86 aw at 30 degrees C and was unable to germinate at 37 degrees C. E. repens germinated at 0.70 aw at 30 degrees C, but at 25 and 37 degrees C, its minimum aw for germination was 0.74. C. xerophilum and X. bisporus germinated at 0.70 aw at all three temperatures. The optimum growth occurred at 25 degrees C for P. roqueforti and W. sebi, at 30 degrees C for Eurotium species, A. penicillioides and X. bisporus and at 37 degrees C for C. xerophilum. These fungi all grew faster under acidic than neutral pH conditions. The data presented here provide a matrix that will be used in the development of a mathematical model for the prediction of the shelf life of baked goods and confectionery.

  15. Streamers sliding on a water surface

    Science.gov (United States)

    Akishev, Yuri Semenov; Karalnik, Vladimir; Medvedev, Mikhail; Petryakov, Alexander; Trushkin, Nikolay; Shafikov, Airat

    2017-06-01

    The features of an electrical interaction between surface streamers (thin current filaments) sliding on a liquid and liquid itself are still unknown in many details. This paper presents the experimental results on properties of the surface streamers sliding on water with different conductivity (distilled and tap water). The streamers were initiated with a sharpened thin metallic needle placed above the liquid and stressed with a periodical or pulsed high voltage. Two electrode systems were used and tested. The first of them provides in advance the existence of the longitudinal electric field above the water. The second one imitates the electrode geometry of a pin-to-plane dielectric barrier discharge in which the barrier is a thick layer of liquid. The electrical and optical characteristics of streamers were complemented with data on the spectroscopic measurements. It was revealed that surface streamers on water have no spatial memory. Contribution to the topical issue "The 15th International Symposium on High Pressure Low Temperature Plasma Chemistry (HAKONE XV)", edited by Nicolas Gherardi and Tomáš Hoder

  16. Uncertainty in surface water flood risk modelling

    Science.gov (United States)

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

    2009-04-01

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

  17. Coral records of reef-water pH across the central Great Barrier Reef, Australia: assessing the influence of river runoff on inshore reefs

    Directory of Open Access Journals (Sweden)

    J. P. D'Olivo

    2014-07-01

    Full Text Available The boron isotopic (δ11Bcarb compositions of long-lived Porites coral are used to reconstruct reef-water pH across the central Great Barrier Reef (GBR and assess the impact of river runoff on inshore reefs. For the period from 1940 to 2009, corals from both inner as well as mid-shelf sites exhibit the same overall decrease in δ11Bcarb of 0.086 ± 0.033‰ per decade, equivalent to a~decline in seawater pH (pHsw of ~ 0.017 ± 0.007 pH units per decade. This decline is consistent with the long-term effects of ocean acidification based on estimates of CO2 uptake by surface waters due to rising atmospheric levels. We also find that compared to the mid-shelf corals, the δ11Bcarb compositions for inner shelf corals subject to river discharge events, have higher and more variable values and hence higher inferred pHsw values. These higher δ11Bcarb values for inner-shelf corals are particularly evident during wet years, despite river waters having lower pH. The main effect of river discharge on reef-water carbonate chemistry thus appears to be from higher nutrients driving increased phytoplankton productivity, resulting in the drawdown of pCO2 and increase in pHsw. Increased primary production therefore has the potential to counter the more transient effects of low pH river water (pHrw discharged into near-shore environments. Importantly however, inshore reefs also show a consistent pattern of sharply declining coral growth that coincides with periods of high river discharge. This occurs despite these reefs having higher pHsw values and hence higher seawater aragonite saturation states, demonstrating the over-riding importance of local reef-water quality on coral reef health.

  18. Variations in pH caused by porous ceramic capsules in water sampling in non-saturated areas; Variaciones del pH inducidas por las capsulas de ceramica porosa en el muestreo de agua en la zona no saturada

    Energy Technology Data Exchange (ETDEWEB)

    Torre de la Sanchez, M. L.; Grande Gil, J. A.; Garrido Morillo, R. [Escuela Politecnica Superior La Rabida. Palos de La Frontera. Huelva (Spain)

    1999-05-01

    Porous ceramic capsules are a very useful tool for water sampling in non-saturated areas. However, several authors have found variations in pH in the water collected by such capsules. This paper compares the variation in pH distilled water and in different concentrations of saline solution. A large increase in pH was found due to the release process and subsequent precipitation of calcium ions from the ceramic. (Author) 5 refs.

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

    Science.gov (United States)

    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

  20. Influence of Water Temperature and Salinity on PH During Dry Season in Lower Dong Nai River System, Vietnam

    Directory of Open Access Journals (Sweden)

    Dung Dang Quoc

    2015-12-01

    Full Text Available This paper uses the gvSIG 2.2.0 software, IDW interpolation method, river and stream network data, and 36 sampling sites to build the maps of three monitored parameters such as pH, water temperature, and salinity in the Lower Dong Nai River system (2009-2010 in dry season. Based on an analysis of these maps and statistical assessment by using the R software, the correlations between pH, temperature, and salinity are clarified. The results show that the pH and temperature values have a tendency to decrease, whereas the salinity tends to increase annually. The pH value has good and significant correlations with the water temperature and salinity in both simple and multiple linear regression models. The results aim to provide a scientific reference for further research on the water environment in this area.

  1. How Water Advances on Superhydrophobic Surfaces

    Science.gov (United States)

    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.

  2. Convergent surface water distributions in U.S. cities

    Science.gov (United States)

    M.K. Steele; J.B. Heffernan; N. Bettez; J. Cavender-Bares; P.M. Groffman; J.M. Grove; S. Hall; S.E. Hobbie; K. Larson; J.L. Morse; C. Neill; K.C. Nelson; J. O' Neil-Dunne; L. Ogden; D.E. Pataki; C. Polsky; R. Roy Chowdhury

    2014-01-01

    Earth's surface is rapidly urbanizing, resulting in dramatic changes in the abundance, distribution and character of surface water features in urban landscapes. However, the scope and consequences of surface water redistribution at broad spatial scales are not well understood. We hypothesized that urbanization would lead to convergent surface water abundance and...

  3. Improved photoelectrochemical water oxidation kinetics using a TiO2 nanorod array photoanode decorated with graphene oxide in a neutral pH solution.

    Science.gov (United States)

    Chae, Sang Youn; Sudhagar, Pitchaimuthu; Fujishima, Akira; Hwang, Yun Jeong; Joo, Oh-Shim

    2015-03-28

    We prepared TiO2 nanorod (NR) arrays on a fluorine-doped tin oxide substrate and decorated with graphene oxide (GO) to study their photoelectrochemical (PEC) water oxidation activities in two different electrolytes. The PEC performances of GO-decorated TiO2 NR photoanodes were characterized by optical and electrochemical impedance spectroscopy measurements. In 1 M KOH, the photocurrent density of the TiO2 NR film decreased after deposition of GO, while in the neutral pH electrolyte (phosphate buffered 0.5 M Na2SO4), the TiO2 NR photoanode showed enhanced performance after deposition with the 2 wt% GO solution. This was a consequence of the decrease in charge transfer resistance between the electrode surface and the electrolyte. The improvement of photocurrents by GO decoration was obvious near the onset potential of the photocurrents in the neutral pH electrolyte. These opposite contributions of GO on the TiO2 NR photoanodes suggest that GO can promote water oxidation effectively in a neutral electrolyte because depending on the pH of the electrolyte, different chemical species interact with the surface of the photoanode in the water oxidation reaction.

  4. Quality of surface-water supplies in the Triangle area of North Carolina, water year 2009

    Science.gov (United States)

    Pfeifle, C. A.; Giorgino, M. J.; Rasmussen, R. B.

    2014-01-01

    Surface-water supplies are important sources of drinking water for residents in the Triangle area of North Carolina, which is located within the upper Cape Fear and Neuse River Basins. Since 1988, the U.S. Geological Survey and a consortium of governments have tracked water-quality conditions and trends in several of the area’s water-supply lakes and streams. This report summarizes data collected through this cooperative effort, known as the Triangle Area Water Supply Monitoring Project, during October 2008 through September 2009. Major findings for this period include: - Annual precipitation was approximately 20 percent below the long-term mean (average) annual precipitation. - Streamflow was below the long-term mean at the 10 project streamgages during most of the year. - More than 7,000 individual measurements of water quality were made at a total of 26 sites—15 in the Neuse River Basin and 11 in the Cape Fear River Basin. Forty-seven water-quality properties and constituents were measured. - All observations met North Carolina water-quality standards for water temperature, pH, hardness, chloride, fluoride, sulfate, nitrate, arsenic, cadmium, chromium, lead, nickel, and selenium. - North Carolina water-quality standards were exceeded one or more times for dissolved oxygen, dissolved oxygen percent saturation, chlorophyll a, mercury, copper, iron, manganese, silver, and zinc. Exceedances occurred at 23 sites—13 in the Neuse River Basin and 10 in the Cape Fear River Basin. - Stream samples collected during storm events contained elevated concentrations of 18 water-quality constituents compared to samples collected during non-storm events. - Concentrations of nitrogen and phosphorus were within ranges observed during previous years. - Five reservoirs had chlorophyll a concentrations in excess of 40 micrograms per liter at least once during 2009: Little River Reservoir, Falls Lake, Cane Creek Reservoir, University Lake, and Jordan Lake.

  5. Transformation of Coordinate Forms of Phosphate Adsorbed on Goethite Surfaces Under Conditions of Varying pH

    Institute of Scientific and Technical Information of China (English)

    JIEXIAO-LEI; WANGDIAN-FEN; 等

    1995-01-01

    X-ray photoelectron spectroscopy(XPS) and automatic titrimeter were used to study the relation bewteen pH and the transformation of the coordinate forms of P on goethite surfaces.The results showed that for a given P concentration,increasing the pH of suspension could cause a fast transformation of monodentate complexes of phosphate ions on goethite surfaces to binuclear ones,When lowering the pH,additional adsorption of P occurred and the binuclear complexes reverted slowly to the monodentate ones,The dissociation and association of protons of the sorbed P caused by pH changes was considered to be a major reason leading to the transformation of the coordinate forms of P on the surfaces.The stability of binuclear surface complex of P was greater than that of monodentate omplex.The possible reactions on the interface of goethite and solutions with pH changes,and the reasons causing the different stabilities of the two coordinate P complexes are discussed in the paper.

  6. Bacteriophages as surface and ground water tracers

    Directory of Open Access Journals (Sweden)

    P. Rossi

    1998-01-01

    Full Text Available 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.

  7. Bacteriophages as surface and ground water tracers

    Science.gov (United States)

    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.

  8. Water droplet evaporation from sticky superhydrophobic surfaces

    Science.gov (United States)

    Lee, Moonchan; Kim, Wuseok; Lee, Sanghee; Baek, Seunghyeon; Yong, Kijung; Jeon, Sangmin

    2017-07-01

    The evaporation dynamics of water from sticky superhydrophobic surfaces was investigated using a quartz crystal microresonator and an optical microscope. Anodic aluminum oxide (AAO) layers with different pore sizes were directly fabricated onto quartz crystal substrates and hydrophobized via chemical modification. The resulting AAO layers exhibited hydrophobic or superhydrophobic characteristics with strong adhesion to water due to the presence of sealed air pockets inside the nanopores. After placing a water droplet on the AAO membranes, variations in the resonance frequency and Q-factor were measured throughout the evaporation process, which were related to changes in mass and viscous damping, respectively. It was found that droplet evaporation from a sticky superhydrophobic surface followed a constant contact radius (CCR) mode in the early stage of evaporation and a combination of CCR and constant contact angle modes without a Cassie-Wenzel transition in the final stage. Furthermore, AAO membranes with larger pore sizes exhibited longer evaporation times, which were attributed to evaporative cooling at the droplet interface.

  9. Effects of overlying water aeration on phosphorus fractions and alkaline phosphatase activity in surface sediment

    Institute of Scientific and Technical Information of China (English)

    Jianjun Chen; Shaoyong Lu; Yikun Zhao; Wei Wang; Minsheng Huang

    2011-01-01

    Microbial activity may influence phosphorus (P) deposit and release at the water sediment interface.The properties of DO (dissolved oxygen), pH, P fractions (TP, Ca-P, Fe-P, OP, IP), and APA (alkaline phosphatase activity) at the water sediment interface were measured to investigate microbial activity variations in surface sediment under conditions of two-month intermittent aeration in overlying water.Results showed that DO and TP of overlying water increased rapidly in the first week and then decreased gradually after 15 day of intermittent aeration.Microorganism metabolism in surface sediment increased pH and decreased DO and TP in the overlying water.After two-month intermittent aeration, APA and OP from surface sediment (0-2 crm) were both significantly higher than those from bottom sediment (6-8 cm) (p < 0.05), and surface sediment Fe-P was transferred to OP during the course of microorganism reproduction on the surface sediment.These results suggest that microbial activity and microorganism biomass from the surface sediment were higher than those from bottom sediment afar two-month intermittent aeration in the overlying water.

  10. PIP Water Transport and Its pH Dependence Are Regulated by Tetramer Stoichiometry.

    Science.gov (United States)

    Jozefkowicz, Cintia; Sigaut, Lorena; Scochera, Florencia; Soto, Gabriela; Ayub, Nicolás; Pietrasanta, Lía Isabel; Amodeo, Gabriela; González Flecha, F Luis; Alleva, Karina

    2016-03-29

    Many plasma membrane channels form oligomeric assemblies, and heterooligomerization has been described as a distinctive feature of some protein families. In the particular case of plant plasma membrane aquaporins (PIPs), PIP1 and PIP2 monomers interact to form heterotetramers. However, the biological properties of the different heterotetrameric configurations formed by PIP1 and PIP2 subunits have not been addressed yet. Upon coexpression of tandem PIP2-PIP1 dimers in Xenopus oocytes, we can address, for the first time to our knowledge, the functional properties of single heterotetrameric species having 2:2 stoichiometry. We have also coexpressed PIP2-PIP1 dimers with PIP1 and PIP2 monomers to experimentally investigate the localization and biological activity of each tetrameric assembly. Our results show that PIP2-PIP1 heterotetramers can assemble with 3:1, 1:3, or 2:2 stoichiometry, depending on PIP1 and PIP2 relative expression in the cell. All PIP2-PIP1 heterotetrameric species localize at the plasma membrane and present the same water transport capacity. Furthermore, the contribution of any heterotetrameric assembly to the total water transport through the plasma membrane doubles the contribution of PIP2 homotetramers. Our results also indicate that plasma membrane water transport can be modulated by the coexistence of different tetrameric species and by intracellular pH. Moreover, all the tetrameric species present similar cooperativity behavior for proton sensing. These findings throw light on the functional properties of PIP tetramers, showing that they have flexible stoichiometry dependent on the quantity of PIP1 and PIP2 molecules available. This represents, to our knowledge, a novel regulatory mechanism to adjust water transport across the plasma membrane.

  11. Vertical and horizontal distribution of Desmophyllum dianthus in Comau Fjord, Chile: a cold-water coral thriving at low pH.

    Science.gov (United States)

    Fillinger, Laura; Richter, Claudio

    2013-01-01

    Cold-water corals provide an important habitat for a rich fauna along the continental margins and slopes. Although these azooxanthellate corals are considered particularly sensitive to ocean acidification, their responses to natural variations in pH and aragonite saturation are largely unknown due to the difficulty of studying their ecology in deep waters. Previous SCUBA investigations have shown an exceptionally shallow population of the cold-water coral Desmophyllum dianthus in near-surface waters of Comau Fjord, a stratified 480 m deep basin in northern Chilean Patagonia with suboxic deep waters. Here, we use a remotely operated vehicle to quantitatively investigate the distribution of D. dianthus and its physico-chemical drivers in so far uncharted naturally acidified waters. Remarkably, D. dianthus was ubiquitous throughout the fjord, but particularly abundant between 20 and 280 m depth in a pH range of 8.4 to 7.4. The persistence of individuals in aragonite-undersaturated waters suggests that present-day D. dianthus in Comau Fjord may show pre-acclimation or pre-adaptation to conditions of ocean acidification predicted to reach over 70% of the known deep-sea coral locations by the end of the century.

  12. Vertical and horizontal distribution of Desmophyllum dianthus in Comau Fjord, Chile: a cold-water coral thriving at low pH

    Directory of Open Access Journals (Sweden)

    Laura Fillinger

    2013-10-01

    Full Text Available Cold-water corals provide an important habitat for a rich fauna along the continental margins and slopes. Although these azooxanthellate corals are considered particularly sensitive to ocean acidification, their responses to natural variations in pH and aragonite saturation are largely unknown due to the difficulty of studying their ecology in deep waters. Previous SCUBA investigations have shown an exceptionally shallow population of the cold-water coral Desmophyllum dianthus in near-surface waters of Comau Fjord, a stratified 480 m deep basin in northern Chilean Patagonia with suboxic deep waters. Here, we use a remotely operated vehicle to quantitatively investigate the distribution of D. dianthus and its physico-chemical drivers in so far uncharted naturally acidified waters. Remarkably, D. dianthus was ubiquitous throughout the fjord, but particularly abundant between 20 and 280 m depth in a pH range of 8.4 to 7.4. The persistence of individuals in aragonite-undersaturated waters suggests that present-day D. dianthus in Comau Fjord may show pre-acclimation or pre-adaptation to conditions of ocean acidification predicted to reach over 70% of the known deep-sea coral locations by the end of the century.

  13. Coral records of reef-water pH across the central Great Barrier Reef, Australia: assessing the influence of river runoff on inshore reefs

    Science.gov (United States)

    D'Olivo, J. P.; McCulloch, M. T.; Eggins, S. M.; Trotter, J.

    2015-02-01

    The boron isotopic (δ11Bcarb) compositions of long-lived Porites coral are used to reconstruct reef-water pH across the central Great Barrier Reef (GBR) and assess the impact of river runoff on inshore reefs. For the period from 1940 to 2009, corals from both inner- and mid-shelf sites exhibit the same overall decrease in δ11Bcarb of 0.086 ± 0.033‰ per decade, equivalent to a decline in seawater pH (pHsw) of ~0.017 ± 0.007 pH units per decade. This decline is consistent with the long-term effects of ocean acidification based on estimates of CO2 uptake by surface waters due to rising atmospheric levels. We also find that, compared to the mid-shelf corals, the δ11Bcarb compositions of inner-shelf corals subject to river discharge events have higher and more variable values, and hence higher inferred pHsw values. These higher δ11Bcarb values of inner-shelf corals are particularly evident during wet years, despite river waters having lower pH. The main effect of river discharge on reef-water carbonate chemistry thus appears to be from reduced aragonite saturation state and higher nutrients driving increased phytoplankton productivity, resulting in the drawdown of pCO2 and increase in pHsw. Increased primary production therefore has the potential to counter the more transient effects of low-pH river water (pHrw) discharged into near-shore environments. Importantly, however, inshore reefs also show a consistent pattern of sharply declining coral growth that coincides with periods of high river discharge. This occurs despite these reefs having higher pHsw, demonstrating the overriding importance of local reef-water quality and reduced aragonite saturation state on coral reef health.

  14. Screen-printed calcium-birnessite electrodes for water oxidation at neutral pH and an "electrochemical harriman series".

    Science.gov (United States)

    Lee, Seung Y; González-Flores, Diego; Ohms, Jonas; Trost, Tim; Dau, Holger; Zaharieva, Ivelina; Kurz, Philipp

    2014-12-01

    A mild screen-printing method was developed to coat conductive oxide surfaces (here: fluorine-doped tin oxide) with micrometer-thick layers of presynthesized calcium manganese oxide (Ca-birnessite) particles. After optimization steps concerning the printing process and layer thickness, electrodes were obtained that could be used as corrosion-stable water-oxidizing anodes at pH 7 to yield current densities of 1 mA cm(-2) at an overpotential of less than 500 mV. Analyses of the electrode coatings of optimal thickness (≈10 μm) indicated that composition, oxide phase, and morphology of the synthetic Ca-birnessite particles were hardly affected by the screen-printing procedure. However, a more detailed analysis by X-ray absorption spectroscopy revealed small modifications of both the Mn redox state and the structure at the atomic level, which could affect functional properties such as proton conductivity. Furthermore, the versatile new screen-printing method was used for a comparative study of various transition-metal oxides concerning electrochemical water oxidation under "artificial leaf conditions" (neutral pH, fairly low overpotential and current density), for which a general activity ranking of RuO2 >Co3 O4 ≈(Ca)MnOx ≈NiO was observed. Within the group of screened manganese oxides, Ca-birnessite performed better than "Mn-only materials" such as Mn2 O3 and MnO2 .

  15. Visible-infrared remote-sensing model and applications for ocean waters. Ph.D. Thesis

    Science.gov (United States)

    Lee, Zhongping

    1994-01-01

    Remote sensing has become important in the ocean sciences, especially for research involving large spatial scales. To estimate the in-water constituents through remote sensing, whether carried out by satellite or airplane, the signal emitted from beneath the sea surface, the so called water-leaving radiance (L(w)), is of prime importance. The magnitude of L(w) depends on two terms: one is the intensity of the solar input, and the other is the reflectance of the in-water constituents. The ratio of the water-leaving radiance to the downwelling irradiance (E(d)) above the sear surface (remote-sensing reflectance, R(sub rs)) is independent of the intensity of the irradiance input, and is largely a function of the optical properties of the in-water constituents. In this work, a model is developed to interpret r(sub rs) for ocean water in the visible-infrared range. In addition to terms for the radiance scattered from molecules and particles, the model includes terms that describe contributions from bottom reflectance, fluorescence of gelbstoff or colored dissolved organic matter (CDOM), and water Raman scattering. By using this model, the measured R(sub rs) of waters from the West Florida Shelf to the Mississippi River plume, which covered a (concentration of chlorophyll a) range of 0.07 - 50 mg/cu m, were well interpreted. The average percentage difference (a.p.d.) between the measured and modeled R(sub rs) is 3.4%, and, for the shallow waters, the model-required water depth is within 10% of the chart depth. Simple mathematical simulations for the phytoplankton pigment absorption coefficient (a(sub theta)) are suggested for using the R(sub rs) model. The inverse problem of R(sub rs), which is to analytically derive the in-water constituents from R(sub rs) data alone, can be solved using the a(sub theta) functions without prior knowledge of the in-water optical properties. More importantly, this method avoids problems associated with a need for knowledge of the shape

  16. Chemistry and dissolved gases of matrix pore water and fluid inclusions in Olkiluoto bedrock from drillhole ONK-PH9

    Energy Technology Data Exchange (ETDEWEB)

    Eichinger, F.; Haemmerli, J.; Waber, H.N.; Diamond, L.W. [Univ. of Bern (Switzerland). Inst. of Geological Sciences; Smellie, J.A.T. [Conterra AB, Stockholm (Sweden)

    2013-05-15

    Matrix pore water and gas dissolved in matrix pore water in drillcore samples from drillhole ONK-PH9 have been successfully characterised for their chemical and isotopic composition. Based on the comparison of natural tracers in matrix pore water and adjacent fracture groundwater, conclusions about the palaeohydrogeological history of the encountered system are drawn. The investigations are based on naturally saturated core samples from the subhorizontal drillhole ONK-PH9 which was drilled from the ONKALO access tunnel at a vertical depth of 306 m into the bedrock intersecting the water-conducting hydrogeological zone HZ20B. Pore water samples were taken from this highly transmissive water-conducting zone and the adjacent low transmissive bedrock along a continuous eleven metre long profile. Additional samples have been collected at intervals between five and ten metres until 100 m drillhole length (DHL)

  17. Effect of pH on the formation of disinfection byproducts in swimming pool water – Is less THM better?

    OpenAIRE

    Hansen, Kamilla Marie Speht; Willach, Sarah; Antoniou, Maria; Mosbæk, Hans; Albrechtsen, Hans-Jørgen; Andersen, Henrik Rasmus

    2012-01-01

    This study investigated the formation and predicted toxicity of different groups of disinfection byproducts (DBPs) from human exudates in relation to chlorination of pool water at different pH values. Specifically, the formation of the DBP groups trihalomethanes (THMs), haloacetic acids (HAAs), haloacetonitriles (HANs) and trichloramine (NCl3), resulting from the chlorination of body fluid analog, were investigated at 6.0 ≤ pH ≤ 8.0. Either the initial concentration of active chorine or free ...

  18. The adhesion of mussel foot protein-3 to TiO2 surfaces: the effect of pH

    Science.gov (United States)

    Yu, Jing; Wei, Wei; Menyo, Matthew S.; Masic, Admir; Waite, J. Herbert; Israelachvili, Jacob N.

    2013-01-01

    The underwater adhesion of marine mussels relies on mussel foot proteins (mfps) rich in the catecholic amino acid 3, 4-dihydroxyphenylalanine (Dopa). As a side-chain, Dopa is capable of strong bidentate interactions with a variety of surfaces, including many minerals and metal oxides. Titanium is among the most widely used medical implant material and quickly forms a TiO2 passivation layer under physiological conditions. Understanding the binding mechanism of Dopa to TiO2 surfaces is therefore of considerable theoretical and practical interest. Using a surface forces apparatus, we explored the force-distance profiles and adhesion energies of mussel foot protein 3 (mfp-3) to TiO2 surfaces at three different pHs (pH3, 5.5 and 7.5). At pH3, mfp-3 showed the strongest adhesion force on TiO2, with an adhesion energy of ~ −7.0 mJ/m2. Increasing the pH gives rise to two opposing effects: (1) increased oxidation of Dopa, thus decreasing availability for the Dopa-mediated adhesion, and (2) increased bidentate Dopa-Ti coordination, leading to the further stabilization of the Dopa group and thus an increasing of adhesion force. Both effects were reflected in the resonance-enhanced Raman spectra obtained at the three deposition pHs. The two competing effects give rise to a higher adhesion force of mfp-3 on TiO2 surface at pH 7.5 than at pH 5.5. Our results suggest that Dopa-containing proteins and synthetic polymers have great potential as coating materials for medical implant materials, particularly if redox activity can be controlled. PMID:23452271

  19. Oxidative stability of 70% fish oil‐in‐water emulsions: Impact of emulsifiers and pH

    DEFF Research Database (Denmark)

    Horn, Anna Frisenfeldt; Nielsen, Nina Skall; Andersen, Ulf

    2011-01-01

    or protein based. The PL‐based emulsifiers were soy lecithin and two milk PL concentrates (with either 20 or 75% PL). The protein‐based emulsifiers were whey protein isolate and sodium caseinate. Lipid oxidation was studied at two pH values (pH 4.5 and 7.0) and results were compared to lipid oxidation......‐in‐water emulsions prepared with whey protein isolate, sodium caseinate, milk phospholipids, or soy lecithin. The emulsions can be used as delivery systems for fish oil to foods. However, only emulsions prepared with proteins at high pH offered advantages with respect to better oxidative stability during storage...

  20. Water pH and temperature in Lake Biwa from MBT'/CBT indices during the last 282 000 years

    Science.gov (United States)

    Ajioka, T.; Yamamoto, M.; Takemura, K.; Hayashida, A.

    2014-03-01

    We generated a 282 000-year record of water pH and temperature in Lake Biwa, central Japan, by analysing the methylation index (MBT') and cyclisation ratio (CBT) of branched tetraethers in sediments from piston and borehole cores to understand the responses of precipitation and air temperature in central Japan to the East Asian monsoon variability on the orbital timescale. Because water pH in Lake Biwa is determined by phosphorus input driven by precipitation, the record of water pH should indicate changes in summer precipitation in central Japan. The estimated pH showed significant periodicity at 19 and 23 ka (precession) and at 41 ka (obliquity). The variation in the estimated pH agrees with variation in the pollen temperature index. This indicates synchronous variation in summer air temperature and precipitation in central Japan, which contradicts the conclusions of previous studies. The variation in estimated pH was also synchronous with the variation of oxygen isotopes in stalagmites in China, suggesting that East Asian summer monsoon precipitation was governed by Northern Hemisphere summer insolation on orbital timescales. However, the estimated winter temperatures were higher during interglacials and lower during glacials, showing an eccentricity cycle. This suggests that the temperature variation reflected winter monsoon variability.

  1. Water-wettable polypropylene fibers by facile surface treatment based on soy proteins.

    Science.gov (United States)

    Salas, Carlos; Genzer, Jan; Lucia, Lucian A; Hubbe, Martin A; Rojas, Orlando J

    2013-07-24

    Modification of the wetting behavior of hydrophobic surfaces is essential in a variety of materials, including textiles and membranes that require control of fluid interactions, adhesion, transport processes, sensing, etc. This investigation examines the enhancement of wettability of an important class of textile materials, viz., polypropylene (PP) fibers, by surface adsorption of different proteins from soybeans, including soy flour, isolate,glycinin, and β-conglycinin. Detailed investigations of soy adsorption from aqueous solution (pH 7.4, 25 °C) on polypropylene thin films is carried out using quartz crystal microbalance (QCM) and surface plasmon resonance (SPR). A significant amount of protein adsorbs onto the PP surfaces primarily due to hydrophobic interactions. We establish that adsorption of a cationic surfactant, dioctadecyldimethylammonium bromide (DODA) onto PP surfaces prior to the protein deposition dramatically enhances its adsorption. The adsorption of proteins from native (PBS buffer, pH 7.4, 25 °C) and denatured conditions (PBS buffer, pH 7.4, 95 °C) onto DODA-treated PP leads to a high coverage of the proteins on the PP surface as confirmed by a significant improvement in water wettability. A shift in the contact angle from 128° to completely wettable surfaces (≈0°) is observed and confirmed by imaging experiments conducted with fluorescence tags. Furthermore, the results from wicking tests indicate that hydrophobic PP nonwovens absorb a significant amount of water after protein treatment, i.e., the PP-modified surfaces become completely hydrophilic.

  2. Solubility controls on aluminum in drinking water at relatively low and high pH.

    Science.gov (United States)

    Kvech, Steve; Edwards, Marc

    2002-10-01

    Potential control of soluble aluminum in drinking water by formation of solids other than Al(OH)3 was examined. At pHs below 6.0, Al(+3) solids containing sulfate, silica or potassium are thermodynamically favored versus amorphous Al(OH)3; however, in this work no evidence could be obtained that solids other than Al(OH)3 would form in practice. At pHs above 9, aluminum and magnesium were discovered to form complex solid phases of approximate composition AlMg2(OH)7, AlMg2SiO2(OH)7 or Al(SiO2)2(OH)3 dependent on circumstance. Formation of these solids provide a mechanistic explanation for enhancements to precipitative softening obtained in practice by dosing Al(+3) salts; that is, improved flocculation/settling and removal of silica from water that interferes with calcium precipitation. The solids also maintain residual aluminum below regulatory guidelines at high pH > 9.5.

  3. Effect of pH on the formation of disinfection byproducts in swimming pool water--is less THM better?

    Science.gov (United States)

    Hansen, Kamilla M S; Willach, Sarah; Antoniou, Maria G; Mosbæk, Hans; Albrechtsen, Hans-Jørgen; Andersen, Henrik R

    2012-12-01

    This study investigated the formation and predicted toxicity of different groups of disinfection byproducts (DBPs) from human exudates in relation to chlorination of pool water at different pH values. Specifically, the formation of the DBP groups trihalomethanes (THMs), haloacetic acids (HAAs), haloacetonitriles (HANs) and trichloramine (NCl(3)), resulting from the chlorination of body fluid analog, were investigated at 6.0 ≤ pH ≤ 8.0. Either the initial concentration of active chorine or free chlorine was kept constant in the tested pH range. THM formation was reduced by decreasing pH but HAN, and NCl(3) formation increased at decreasing pH whereas the formation of HAAs remained constant. Under our experimental conditions, the formation of NCl(3) (suspected asthma inducing compound) at pH = 6.0 was an order of magnitude higher than at pH = 7.5. Furthermore, the effect of the presence of bromide on DBP formation was investigated and found to follow the same pH dependency as without bromide present, with the overall DBP formation increasing, except for HAAs. Estimation of genotoxicity and cytotoxicity of the chlorinated human exudates showed that among the quantified DBP groups, HAN formation were responsible for the majority of the toxicity from the measured DBPs in both absence and presence of bromide.

  4. Volatile composition of sunflower oil-in-water emulsions during initial lipid oxidation: influence of pH.

    Science.gov (United States)

    van Ruth, S M; Roozen, J P; Posthumus, M A; Jansen, F J

    1999-10-01

    The formation of odor active compounds resulting from initial lipid oxidation in sunflower oil-in-water emulsions was examined during storage at 60 degrees C. The emulsions differed in initial pH, that is, pH 3 and 6. The volatile compounds were isolated under mouth conditions and were analyzed by gas chromatography/sniffing port analysis. The lipid oxidation rate was followed by the formation of conjugated hydroperoxide dienes and headspace hexanal. The initial pH affected the lipid oxidation rate in the emulsions: the formation of conjugated diene hydroperoxides and the hexanal concentration in the static headspace were increased at pH 6. Pentanal, hexanal, 3-pentanol, and 1-octen-3-one showed odor activity in the emulsions after 6 days of storage, for both pH 3 and 6. Larger amounts of odor active compounds were released from the pH 6 emulsion with extended storage. It was shown that this increased release at pH 6 was not due to increased volatility because an increase in pH diminished the static headspace concentrations of added compounds in emulsions.

  5. Nitrate reducing activity pervades surface waters during upwelling.

    Digital Repository Service at National Institute of Oceanography (India)

    Fernandes, S.O.; Halarnekar, R.; Malik, A.; Vijayan, V.; Varik, S.; RituKumari; Jineesh V.K.; Gauns, M.U.; Nair, S.; LokaBharathi, P.A.

    Nitrate reducing activity (NRA) is known to be mediated by microaerophilic to anaerobic bacteria and generally occurs in the sub-surface waters. However, we hypothesize that NRA could become prominent in the surface waters during upwelling. Hence...

  6. Effect of rare earths on mechanical properties of plasma nitrocarburized surface layer of 17-4PH steel

    Institute of Scientific and Technical Information of China (English)

    刘瑞良; 闫牧夫; 吴丹蕾

    2009-01-01

    The aim of this investigation is to reveal the influence of rare earths(RE) addition on mechanical properties of plasma nitrocarburized 17-4PH steel.The nitrocarburized layers were characterized by optical microscope,scanning electron microscope equipped with energy dispersive X-ray analyzer,X-ray diffractometer,microhardness tester and pin-on-disc tribometer.The results showed that RE atoms could diffuse into the surface layer of 17-4PH steel plasma nitrocarburized at 500 °C for 4 h and did not change the ...

  7. The glycocalyx maintains a cell surface pH nanoenvironment crucial for integrin-mediated migration of human melanoma cells.

    Science.gov (United States)

    Krähling, Hermann; Mally, Sabine; Eble, Johannes A; Noël, Josette; Schwab, Albrecht; Stock, Christian

    2009-10-01

    The glycocalyx consists of proteoglycans, glycoproteins, glycosaminoglycans, associated plasma proteins, and soluble glycosaminoglycans and covers the surface of all eukaryotic cells. It mediates specific recognition events, modulates biological processes such as ligand-receptor interactions, and has been proposed to affect tumor metastasis. Here, we studied whether the glycocalyx is required for melanoma cell migration. We diminished the glycocalyx of human melanoma cells by inhibiting posttranslational N-glycosylation or by enzymatic digestion of the N-glycosides. This partial destruction of the glycocalyx reduced melanoma cell migration by up to 60%. It was accompanied by the disintegration of a characteristic pH nanoenvironment typically surrounding migrating cells. Restoring this pH profile by stimulating the activity of the Na(+)/H(+) exchanger NHE1 rescued cell migration even in the absence of an intact glycocalyx. The effects of partially removing the glycocalyx compared to those of knocking down beta(1)-integrin expression points to a close functional correlation between glycocalyx, integrins, and cell surface pH nanoenvironment. We conclude that the glycocalyx is required for tumor cell migration. It stabilizes the cell surface pH nanoenvironment allowing a concerted pH-dependent interaction of adhesion receptors and extracellular matrix.

  8. Wettability and water uptake of holm oak leaf surfaces

    OpenAIRE

    2014-01-01

    Plant trichomes play important protective functions and may have a major influence on leaf surface wettability. With the aim of gaining insight into trichome structure, composition and function in relation to water-plant surface interactions, we analyzed the adaxial and abaxial leaf surface of Quercus ilex L. (holm oak) as model. By measuring the leaf water potential 24 h after the deposition of water drops on to abaxial and adaxial surfaces, evidence for water penetration through the upper l...

  9. Water pH and temperature in Lake Biwa from MBT'/CBT indices during the last 280 000 years

    Science.gov (United States)

    Ajioka, T.; Yamamoto, M.; Takemura, K.; Hayashida, A.; Kitagawa, H.

    2014-10-01

    We generated a 280 000 yr record of water pH and temperature in Lake Biwa, central Japan, by analysing the methylation index (MBT') and cyclisation ratio (CBT) of branched tetraethers in sediments from piston and borehole cores. Our aim was to understand the responses of precipitation and air temperature in central Japan to the East Asian monsoon variability on orbital timescales. Because the water pH in Lake Biwa is determined by phosphorus and alkali cation inputs, the record of water pH should indicate the changes in precipitation and temperature in central Japan. Comparison with a pollen assemblage in a Lake Biwa core suggests that lake water pH was determined by summer temperature in the low-eccentricity period before 55 ka, while it was determined by summer precipitation in the high-eccentricity period after 55 ka. From 130 to 55 ka, the variation in lake pH (summer precipitation) lagged behind that in summer temperature by several thousand years. This perspective is consistent with the conclusions of previous studies (Igarashi and Oba, 2006; Yamamoto, 2009), in that the temperature variation preceded the precipitation variation in central Japan.

  10. Groundwater–surface water interactions in wetlands for integrated water resources management (preface)

    NARCIS (Netherlands)

    Schot, P.P.; Winter, T.C.

    2006-01-01

    Groundwater–surface water interactions constitute an important link between wetlands and the surrounding catchment. Wetlands may develop in topographic lows where groundwater exfiltrates. This water has its functions for ecological processes within the wetland, while surface water outflow from

  11. Fluorine uptake into the human enamel surface from fluoride-containing sealing materials during cariogenic pH cycling

    Science.gov (United States)

    Yasuhiro, Matsuda; Katsushi, Okuyama; Hiroko, Yamamoto; Hisanori, Komatsu; Masashi, Koka; Takahiro, Sato; Naoki, Hashimoto; Saiko, Oki; Chiharu, Kawamoto; Hidehiko, Sano

    2015-04-01

    To prevent the formation of caries and reduce dentin hypersensitivity, sealing materials, either with or without fluoride, are generally applied on the tooth in clinical practice. Application of fluoride-free sealing materials results in the formation of an acid-resistant layer on the tooth surface. On the other hand, fluoride-containing sealing materials might not only form an acid-resistant layer but could possibly further provide fluoride to enhance remineralization and reduce demineralization. In this study, the demineralization prevention ability and fluorine uptake rate in human enamel of fluoride-containing sealing materials ["MS coats F" (MSF)] and fluoride-free sealing materials ("hybrid coats 2" [HI]) were evaluated using an automatic pH cycling system. Each material was applied to the original tooth surface, the cut surfaces were covered with sticky wax, and the automatic pH-cycling system simulated daily acid changes (pH 6.8-4.5) occurring in the oral cavity for 4 weeks. Caries progression was analyzed using transverse microradiography (TMR) taken pre and post the 4 weeks of pH cycling. The fluorine and calcium distributions in the carious lesion in each specimen were evaluated using the proton-induced gamma emission (PIGE) and proton-induced X-ray (PIXE) techniques, respectively. TMR analysis showed that both MSF and HI had a caries-preventing effect after 4 weeks of pH cycling. PIGE/PIXE analysis demonstrated that only MSF resulted in fluoride uptake in the enamel surface. Therefore, MSF can help to form an acid-resistant layer and provide fluoride to the enamel surface. The presence of fluoride on the enamel surface suggested that MSF could prevent demineralization, even if the acid-resistant layer was removed, in clinical settings. The data obtained using the PIGE and PIXE techniques are useful for understanding the benefits of the use of a fluoride-containing sealing material for preventing caries.

  12. General survey and conclusions with regard to the connection of water quantity and water quality studies of surface waters

    NARCIS (Netherlands)

    Rijtema, P.E.

    1979-01-01

    Publikatie die bestaat uit twee delen: 1. General survey of the relation between water quantity and water quality; 2. Conclusions with regard to the connection of water quantity and water quality studies of surface waters

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

    Science.gov (United States)

    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

  14. Study of Water Binding Capacity, pH, Chemical Composition and Microstructure of Livestock Meat and Poultry

    OpenAIRE

    Eleonora Okuskhanova; Maksim Rebezov; Zhanibek Yessimbekov; Anuarbek Suychinov; Natalya Semenova; Yaroslav Rebezov; Olga Gorelik; Oksana Zinina

    2017-01-01

    This paper shows the results of analysis of chemical composition, water binding capacity, pH and microstructure of maral meat, goat meat, lamb, and turkey meat. From the analysis, the high content of protein and ash is observed in turkey meat, fat prevails in lamb, and less amount in maral meat and goat meat. pH value lies between 5.7 (turkey white meat) and 6.4 (goat meat). Low value of water binding capacity is detected in turkey meat (58.2% in red meat, 59.2% in white meat) and high value ...

  15. Effects of carbon, nitrogen and pH on the growth of Aspergillus parasiticus and aflatoxins production in water.

    Science.gov (United States)

    Al-Gabr, Hamid Moh; Ye, Chengsong; Zhang, Yongli; Khan, Sardar; Lin, Huirong; Zheng, Tianling

    2013-04-01

    Mycotoxins are considered as the most hazardous fungal metabolites for human, animals and plant health. Recently, more attention has been paid on the occurrence of this group of fungi in different water sources throughout the globe. In this study, Aspergillus parasiticus ATCC strain was used as representative strain producing aflatoxins in drinking water. This study aimed to investigate the activation of fungi in drinking water and their ability to produce aflatoxins (B1, B2, G1, and G2) in water under different ratios of C:N using different concentrations of total organic carbon (TOC) and total nitrogen (TN). Glucose and ammonium sulphate were used for changing the levels of TOC and TN in the selected water media. Similarly, the effects of different water pH levels from 4.5 to 8.2 on the growth of this group of fungi and aflatoxins production were also investigated. The results indicate that the growth of fungi was highest, at C:N ratio of 1:1 as compared to other selected ratios. Furthermore, the findings indicate that the pH levels 5.5-6.5 showed best growth of fungi as compared to other pH levels. Aflatoxin concentrations were measured in the water samples using HPLC technique, but selected fungi were not able to produce aflatoxins in water at applied concentrations of TOC and TN mimicking the ratios and concentrations present in the natural aquatic environment.

  16. AND logic-like pH- and light-dual controlled drug delivery by surface modified mesoporous silica nanoparticles.

    Science.gov (United States)

    Zhao, Junwei; He, Zhaoshuai; Li, Biao; Cheng, Tanyu; Liu, Guohua

    2017-04-01

    Recently, the controlled drug delivery system has become a potential platform for biomedical application. Herein, we developed a pH and light-dual controlled cargo release system exhibiting AND logic based on MCM-41 mesoporous silica nanoparticles, which was surface modified using β-cyclodextrin (β-CD) with imine bond and azobenzene derivative. The complex of β-CD and azobenzene derivative effectively blocked the cargo delivery in pH=7.0 phosphate buffered saline (PBS) solution without 365nm UV light irradiation. The cargo was fully released when both factors of acidic environment (pH=5.0 PBS) and 365nm UV light irradiation were satisfied, meanwhile only very little cargo was delivered if one factor was satisfied. The result also demonstrates that the opening/closing of the gate and the release of the cargo in small portions can be controlled. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Particle water and pH in the eastern Mediterranean: source variability and implications for nutrient availability

    Science.gov (United States)

    Bougiatioti, Aikaterini; Nikolaou, Panayiota; Stavroulas, Iasonas; Kouvarakis, Giorgos; Weber, Rodney; Nenes, Athanasios; Kanakidou, Maria; Mihalopoulos, Nikolaos

    2016-04-01

    Particle water (liquid water content, LWC) and aerosol pH are important parameters of the aerosol phase, affecting heterogeneous chemistry and bioavailability of nutrients that profoundly impact cloud formation, atmospheric composition, and atmospheric fluxes of nutrients to ecosystems. Few measurements of in situ LWC and pH, however, exist in the published literature. Using concurrent measurements of aerosol chemical composition, cloud condensation nuclei activity, and tandem light scattering coefficients, the particle water mass concentrations associated with the aerosol inorganic (Winorg) and organic (Worg) components are determined for measurements conducted at the Finokalia atmospheric observation station in the eastern Mediterranean between June and November 2012. These data are interpreted using the ISORROPIA-II thermodynamic model to predict the pH of aerosols originating from the various sources that influence air quality in the region. On average, closure between predicted aerosol water and that determined by comparison of ambient with dry light scattering coefficients was achieved to within 8 % (slope = 0.92, R2 = 0.8, n = 5201 points). Based on the scattering measurements, a parameterization is also derived, capable of reproducing the hygroscopic growth factor (f(RH)) within 15 % of the measured values. The highest aerosol water concentrations are observed during nighttime, when relative humidity is highest and the collapse of the boundary layer increases the aerosol concentration. A significant diurnal variability is found for Worg with morning and afternoon average mass concentrations being 10-15 times lower than nighttime concentrations, thus rendering Winorg the main form of particle water during daytime. The average value of total aerosol water was 2.19 ± 1.75 µg m-3, contributing on average up to 33 % of the total submicron mass concentration. Average aerosol water associated with organics, Worg, was equal to 0.56 ± 0.37 µg m-3; thus, organics

  18. Interactions between iron, phenolic compounds, emulsifiers, and pH in omega-3-enriched oil-in-water emulsions

    DEFF Research Database (Denmark)

    Sørensen, Ann-Dorit Moltke; Haahr, Anne-Mette; Becker, E.M.

    2008-01-01

    in a 10% oil-in-water emulsion. The emulsifiers tested were Tween 80 and Citrem, and the phenolic compounds were naringenin, rutin, caffeic acid, and coumaric acid. Lipid oxidation was evaluated at all levels, that is, formation of radicals (ESR), hydroperoxides (PV), and secondary volatile oxidation......The behavior of antioxidants in emulsions is influenced by several factors such as pH and emulsifier type. This study aimed to evaluate the interaction between selected food emulsifiers, phenolic compounds, iron, and pH and their effect on the oxidative stability of n-3 polyunsaturated lipids...... significant effects, as caffeic acid was found to be prooxidative irrespective of pH, emulsifier type, and presence of iron, although the degrees of lipid oxidation were different at the different experimental conditions. The other evaluated phenols were prooxidative at pH 3 in Citrem-stabilized emulsions...

  19. Structured free-water clusters near lubricating surfaces are essential in water-based lubrication.

    Science.gov (United States)

    Hou, Jiapeng; Veeregowda, Deepak H; de Vries, Joop; Van der Mei, Henny C; Busscher, Henk J

    2016-10-01

    Water-based lubrication provides cheap and environmentally friendly lubrication and, although hydrophilic surfaces are preferred in water-based lubrication, often lubricating surfaces do not retain water molecules during shear. We show here that hydrophilic (42° water contact angle) quartz surfaces facilitate water-based lubrication to the same extent as more hydrophobic Si crystal surfaces (61°), while lubrication by hydrophilic Ge crystal surfaces (44°) is best. Thus surface hydrophilicity is not sufficient for water-based lubrication. Surface-thermodynamic analyses demonstrated that all surfaces, regardless of their water-based lubrication, were predominantly electron donating, implying water binding with their hydrogen groups. X-ray photoelectron spectroscopy showed that Ge crystal surfaces providing optimal lubrication consisted of a mixture of -O and =O functionalities, while Si crystal and quartz surfaces solely possessed -O functionalities. Comparison of infrared absorption bands of the crystals in water indicated fewer bound-water layers on hydrophilic Ge than on hydrophobic Si crystal surfaces, while absorption bands for free water on the Ge crystal surface indicated a much more pronounced presence of structured, free-water clusters near the Ge crystal than near Si crystal surfaces. Accordingly, we conclude that the presence of structured, free-water clusters is essential for water-based lubrication. The prevalence of structured water clusters can be regulated by adjusting the ratio between surface electron-donating and electron-accepting groups and between -O and =O functionalities.

  20. VOPcPhO:P3HT composite micro-structures with nano-porous surface morphology

    Science.gov (United States)

    Azmer, Mohamad Izzat; Ahmad, Zubair; Sulaiman, Khaulah; Touati, Farid; Bawazeer, Tahani M.; Alsoufi, Mohammad S.

    2017-03-01

    In this paper, composite micro-structures of Vanadyl 2,9,16,23-tetraphenoxy-29H,31H-phthalocyanine) (VOPcPhO) and Poly (3-hexylthiophene-2,5-diyl) (P3HT) complex with nano-porous surface morphology have been developed by electro-spraying technique. The structural and morphological characteristics of the VOPcPhO:P3HT composite films have been studied by field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). The multidimensional VOPcPhO:P3HT micro-structures formed by electro-spraying with nano-porous surface morphology are very promising for the humidity sensors due to the pore sizes in the range of micro to nano-meters scale. The performance of the VOPcPhO:P3HT electro-sprayed sensor is superior in term of sensitivity, hysteresis and response/recovery times as compared to the spin-coated one. The electro-sprayed humidity sensor exhibits ∼3 times and 0.19 times lower hysteresis in capacitive and resistive mode, respectively, as compared to the spin-coated humidity sensor.

  1. Potentially hazardous substances in surface waters. II. Cholinesterase inhibitors in Dutch surface waters

    NARCIS (Netherlands)

    Greve, P.A.; Freudenthal, J.; Wit, S.L.

    1972-01-01

    Several analytical methods were employed to determine the concentrations of cholinesterase inhibitors in several Dutch surface waters. An Auto-Analyzer method was used for screening purposes; thin-layer chromatography and gas-liquid chromatography-mass spectrometry were used for identification and q

  2. Manipulating and Monitoring On-Surface Biological Reactions by Light-Triggered Local pH Alterations.

    Science.gov (United States)

    Peretz-Soroka, Hagit; Pevzner, Alexander; Davidi, Guy; Naddaka, Vladimir; Kwiat, Moria; Huppert, Dan; Patolsky, Fernando

    2015-07-08

    Significant research efforts have been dedicated to the integration of biological species with electronic elements to yield smart bioelectronic devices. The integration of DNA, proteins, and whole living cells and tissues with electronic devices has been developed into numerous intriguing applications. In particular, the quantitative detection of biological species and monitoring of biological processes are both critical to numerous areas of medical and life sciences. Nevertheless, most current approaches merely focus on the "monitoring" of chemical processes taking place on the sensing surfaces, and little efforts have been invested in the conception of sensitive devices that can simultaneously "control" and "monitor" chemical and biological reactions by the application of on-surface reversible stimuli. Here, we demonstrate the light-controlled fine modulation of surface pH by the use of photoactive molecularly modified nanomaterials. Through the use of nanowire-based FET devices, we showed the capability of modulating the on-surface pH, by intensity-controlled light stimulus. This allowed us simultaneously and locally to control and monitor pH-sensitive biological reactions on the nanodevices surfaces, such as the local activation and inhibition of proteolytic enzymatic processes, as well as dissociation of antigen-antibody binding interactions. The demonstrated capability of locally modulating the on-surface effective pH, by a light stimuli, may be further applied in the local control of on-surface DNA hybridization/dehybridization processes, activation or inhibition of living cells processes, local switching of cellular function, local photoactivation of neuronal networks with single cell resolution and so forth.

  3. Assessment of dry season surface, ground, and treated water quality in the Cape Coast municipality of Ghana.

    Science.gov (United States)

    Quagraine, E K; Adokoh, C K

    2010-01-01

    This aim of this monitoring was to assess water quality in a dry season for the Cape Coast municipality in Ghana, which has been experiencing chronic water shortages. Fifteen different sampling stations--four surface, five ground, and six tap water samples--were analyzed for physicochemical and microbiological parameters during January to April 2005. Levels or trends in water quality that may be deleterious to sensitive water uses, including drinking, irrigation, and livestock watering have been noted with reference to well-established guidelines. Exceedances to some health-based drinking water guidelines included positive coliform for various water samples; pH for all groundwater samples (pH 5.9+/-0.3); conductivity for 50% groundwater; color for about a third of groundwater and tap water; Mn for 44% tap water, 67% groundwater, and 50% surface water samples. The World Health Organization laundry staining Fe guideline of 0.3 mg/l was exceeded by 75% of surface water, 44% tap water, and 53% groundwater samples. The corresponding Mn guideline of 0.1 mg/l was exceeded by all the water samples. Respectively, all surface water samples and also 75% of the surface water exceeded some known Cu and Zn guideline for the protection of aquatic life. Compared to some historic data for Fosu Lagoon, the current study shows a lowering of approximately 1 pH unit, increase of approximately 65% NH3, one to two orders of magnitude increase in PO4(3-), and more than two orders of magnitude increase in NO3-. In several instances, tap water samples collected at the consumers' end of the distribution system did not reflect on the true quality of the treated water. Mn, SO4(2-), PO4(3-), Cu, and Zn were among the chemical contaminations observed to occur in the distribution system.

  4. Lateral Protein-Protein Interactions at Hydrophobic and Charged Surfaces as a Function of pH and Salt Concentration.

    Science.gov (United States)

    Hladílková, Jana; Callisen, Thomas H; Lund, Mikael

    2016-04-07

    Surface adsorption of Thermomyces lanuginosus lipase (TLL)-a widely used industrial biocatalyst-is studied experimentally and theoretically at different pH and salt concentrations. The maximum achievable surface coverage on a hydrophobic surface occurs around the protein isoelectric point and adsorption is reduced when either increasing or decreasing pH, indicating that electrostatic protein-protein interactions in the adsorbed layer play an important role. Using Metropolis Monte Carlo (MC) simulations, where proteins are coarse grained to the amino acid level, we estimate the protein isoelectric point in the vicinity of charged surfaces as well as the lateral osmotic pressure in the adsorbed monolayer. Good agreement with available experimental data is achieved and we further make predictions of the protein orientation at hydrophobic and charged surfaces. Finally, we present a perturbation theory for predicting shifts in the protein isoelectric point due to close proximity to charged surfaces. Although this approximate model requires only single protein properties (mean charge and its variance), excellent agreement is found with MC simulations.

  5. Tolerance of Physocypria kraepelini (Crustacean, Ostracoda) to water-borne ammonia, phosphate and pH value

    Institute of Scientific and Technical Information of China (English)

    YU Na; CHEN Shimei; LI Erchao; CHEN Jiayan; CHEN Liqiao

    2009-01-01

    This study evaluated the median lethal concentration (LC_(50)) and safe concentration of water-borne ammonia,phosphate and pH value on Physocypria kraepelini,a freshwater Ostracoda with a static renewal test system.The results indicated that the LC_(50) values of ammonia for P.kraepelini were 1026.71,859.98,771.79 and 583.82 mg/L at 24,48,72 and 96 h exposure,respectively,and the safe concentration range of ammonia for the long-term survival of P.kraepelini was less than 58.38 mg/L.Finally,the safe range of pH value for the survival of P.kraepelini was from 6.59 to 7.61.P.kraepelini has a high tolerance to ammonia,phosphate and pH value which are the main environmental factors in the serious eutrophication water.

  6. Extracellular pH dynamically controls cell surface delivery of functional TRPV5 channels.

    NARCIS (Netherlands)

    Lambers, T.T.; Oancea, E.; Groot, T. de; Topala, C.N.; Hoenderop, J.G.J.; Bindels, R.J.M.

    2007-01-01

    Extracellular pH has long been known to affect the rate and magnitude of ion transport processes among others via regulation of ion channel activity. The Ca(2+)-selective transient receptor potential vanilloid 5 (TRPV5) channel constitutes the apical entry gate in Ca(2+)-transporting cells, contribu

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

    Science.gov (United States)

    Zhang, W; Zwiazek, J J

    2016-11-01

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

  8. Simulation Programs for Ph.D. Study of Analysis, Modeling and Optimum Design of Solar Domestic Hot Water Systems

    DEFF Research Database (Denmark)

    Qin, Lin

    1999-01-01

    The design of solar domestic hot water system is a complex process, due to characteristics inherent in solar heating technology. Recently, computer simulation has become a widely used technique to improve the understanding of the thermal processes in such systems. This report presents the detailed...... programs or units that were developed in the Ph.D study of " Analysis, Modeling and Optimum Design of Solar Domestic Hot Water Systems"....

  9. Roughness and pH changes of enamel surface induced by soft drinks in vitro-applications of stylus profilometry, focus variation 3D scanning microscopy and micro pH sensor.

    Science.gov (United States)

    Fujii, Mie; Kitasako, Yuichi; Sadr, Alireza; Tagami, Junji

    2011-01-01

    This study aimed to evaluate enamel surface roughness (Ra) and pH before and after erosion by soft drinks. Enamel was exposed to a soft drink (cola, orange juice or green tea) for 1, 5 or 60 min; Ra was measured using contact-stylus surface profilometry (SSP) and non-contact focus variation 3D microscope (FVM). Surface pH was measured using a micro pH sensor. Data were analyzed at significance level of alpha=0.05. There was a significant correlation in Ra between SSP and FVM. FVM images showed no changes in the surface morphology after various periods of exposure to green tea. Unlike cola and orange juice, exposure to green tea did not significantly affect Ra or pH. A significant correlation was observed between surface pH and Ra change after exposure to the drinks. Optical surface analysis and micro pH sensor may be useful tools for non-damaging, quantitative assessment of soft drinks erosion on enamel.

  10. Effect of pH on the formation of disinfection byproducts in swimming pool water – Is less THM better?

    DEFF Research Database (Denmark)

    Hansen, Kamilla Marie Speht; Willach, Sarah; Antoniou, Maria

    2012-01-01

    This study investigated the formation and predicted toxicity of different groups of disinfection byproducts (DBPs) from human exudates in relation to chlorination of pool water at different pH values. Specifically, the formation of the DBP groups trihalomethanes (THMs), haloacetic acids (HAAs...

  11. Significance of pH on the Cytotoxic Potential of the Water Disinfection By-Product Iodoacetic Acid

    Science.gov (United States)

    Significance of pH on the Cytotoxic Potential of the Water Disinfection By-Product Iodoacetic Acid Vicki Richardson1, Susan D. Richardson2, Mary Moyer3, Jane Ellen Simmons1, and Anthony DeAngelo1, 1U.S. Environmental Protection Agency, Research Triangle Park, NC, 2University of...

  12. Monitoring and assessment of surface water acidification following rewetting of oxidised acid sulfate soils.

    Science.gov (United States)

    Mosley, Luke M; Zammit, Benjamin; Jolley, Ann-Marie; Barnett, Liz; Fitzpatrick, Rob

    2014-01-01

    Large-scale exposure of acid sulfate soils during a hydrological drought in the Lower Lakes of South Australia resulted in acidification of surface water in several locations. Our aim was to describe the techniques used to monitor, assess and manage these acidification events using a field and laboratory dataset (n = 1,208) of acidic to circum-neutral pH water samples. The median pH of the acidified (pH  H(+) ≈ Mn(II) > Fe(II/III)) but was about 20 % higher on average. Geochemical speciation calculations and XRD measurements indicated that solid phase minerals (schwertmannite and jarosite for Fe and jurbanite for Al) were likely controlling dissolved metal concentrations and influencing measured acidity between pH 2 and 5.

  13. Grooved organogel surfaces towards anisotropic sliding of water droplets.

    Science.gov (United States)

    Zhang, Pengchao; Liu, Hongliang; Meng, Jingxin; Yang, Gao; Liu, Xueli; Wang, Shutao; Jiang, Lei

    2014-05-21

    Periodic micro-grooved organogel surfaces can easily realize the anisotropic sliding of water droplets attributing to the formed slippery water/oil/solid interface. Different from the existing anisotropic surfaces, this novel surface provides a versatile candidate for the anisotropic sliding of water droplets and might present a promising way for the easy manipulation of liquid droplets for water collection, liquid-directional transportation, and microfluidics.

  14. Adsorption of dyes by ACs prepared from waste tyre reinforcing fibre. Effect of texture, surface chemistry and pH.

    Science.gov (United States)

    Acevedo, Beatriz; Rocha, Raquel P; Pereira, Manuel F R; Figueiredo, José L; Barriocanal, Carmen

    2015-12-01

    This paper compares the importance of the texture and surface chemistry of waste tyre activated carbons in the adsorption of commercial dyes. The adsorption of two commercial dyes, Basic Astrazon Yellow 7GLL and Reactive Rifafix Red 3BN on activated carbons made up of reinforcing fibres from tyre waste and low-rank bituminous coal was studied. The surface chemistry of activated carbons was modified by means of HCl-HNO3 treatment in order to increase the number of functional groups. Moreover, the influence of the pH on the process was also studied, this factor being of great importance due to the amphoteric characteristics of activated carbons. The activated carbons made with reinforcing fibre and coal had the highest SBET, but the reinforcing fibre activated carbon samples had the highest mesopore volume. The texture of the activated carbons was not modified upon acid oxidation treatment, unlike their surface chemistry which underwent considerable modification. The activated carbons made with a mixture of reinforcing fibre and coal experienced the largest degree of oxidation, and so had more acid surface groups. The adsorption of reactive dye was governed by the mesoporous volume, whilst surface chemistry played only a secondary role. However, the surface chemistry of the activated carbons and dispersive interactions played a key role in the adsorption of the basic dye. The adsorption of the reactive dye was more favored in a solution of pH 2, whereas the basic dye was adsorbed more easily in a solution of pH 12. Copyright © 2015 Elsevier Inc. All rights reserved.

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

    Science.gov (United States)

    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.

  16. Factors affecting pH change in alkaline waste water treatment - I

    NARCIS (Netherlands)

    Lijklema, L.

    1969-01-01

    The pH of wastewater in various stages of its purification depends mainly upon the equilibria of carbonic acid. Thus relations between pH and the concentrations of carbon dioxide, bicarbonate and carbonate can be formulated. Corrections for the non-ideal character of the sewage are necessary. With s

  17. Petroleum pollutant degradation by surface water microorganisms.

    Science.gov (United States)

    Antić, Malisa P; Jovancićević, Branimir S; Ilić, Mila; Vrvić, Miroslav M; Schwarzbauer, Jan

    2006-09-01

    It is well known that the composition of petroleum or some of its processing products changes in the environment mostly under the influence of microorganisms. A series of experiments was conducted in order to define the optimum conditions for an efficient biodegradation of petroleum pollutant, or bioremediation of different segments of the environment. The aim of these investigations was to show to what extent the hydrocarbons of a petroleum pollutant are degraded by microbial cultures which were isolated as dominant microorganisms from a surface water of a wastewater canal of an oil refinery and a nitrogen plant. Biodegradation experiments were conducted on one paraffinic, and one naphthenic type of petroleum during a three month period under aerobic conditions, varying the following parameters: Inorganic (Kp) or an organic medium (Bh) with or without exposition to light. Microorganisms were analyzed in a surface water sample from a canal (Pancevo, Serbia), into which wastewater from an oil refinery and a nitrogen plant is released. The consortia of microorganisms were isolated from the water sample (most abundant species: Phormidium foveolarum--filamentous Cyanobacteria, blue-green algae and Achanthes minutissima, diatoms, algae). The simulation experiments of biodegradation were conducted with the biomass suspension and crude oils Sirakovo (Sir, paraffinic type) and Velebit (Ve, naphthenic type). After a three month period, organic substance was extracted by means of chloroform. In the extracts, the content of saturated hydrocarbons, aromatic hydrocarbons, alcohols and fatty acids was determined (the group composition). n-Alkanes and isoprenoid aliphatic alkanes, pristane and phytane, in the aliphatic fractions, were analyzed using gas chromatography (GC). Total isoprenoid aliphatic alkanes and polycyclic alkanes of sterane and triterpane types were analyzed by GC-MS. Paraffinic type petroleums have a significant loss of saturated hydrocarbons. For naphthenic

  18. Fabrication of Superhydrophobic Surfaces with Controllable Electrical Conductivity and Water Adhesion.

    Science.gov (United States)

    Ye, Lijun; Guan, Jipeng; Li, Zhixiang; Zhao, Jingxin; Ye, Cuicui; You, Jichun; Li, Yongjin

    2017-02-14

    A facile and versatile strategy for fabricating superhydrophobic surfaces with controllable electrical conductivity and water adhesion is reported. "Vine-on-fence"-structured and cerebral cortex-like superhydrophobic surfaces are constructed by filtering a suspension of multiwalled carbon nanotubes (MWCNTs), using polyoxymethylene nonwovens as the filter paper. The nonwovens with micro- and nanoporous two-tier structures act as the skeleton, introducing a microscale structure. The MWCNTs act as nanoscale structures, creating hierarchical surface roughness. The surface topography and the electrical conductivity of the superhydrophobic surfaces are controlled by varying the MWCNT loading. The vine-on-fence-structured surfaces exhibit "sticky" superhydrophobicity with high water adhesion. The cerebral cortex-like surfaces exhibit self-cleaning properties with low water adhesion. The as-prepared superhydrophobic surfaces are chemically resistant to acidic and alkaline environments of pH 2-12. They therefore have potential in applications such as droplet-based microreactors and thin-film microextraction. These findings aid our understanding of the role that surface topography plays in the design and fabrication of superhydrophobic surfaces with different water-adhesion properties.

  19. Effect of temperature, water activity, and pH on growth and production of ochratoxin A by Aspergillus niger and Aspergillus carbonarius from Brazilian grapes.

    Science.gov (United States)

    Passamani, Fabiana Reinis Franca; Hernandes, Thais; Lopes, Noelly Alves; Bastos, Sabrina Carvalho; Santiago, Wilder Douglas; Cardoso, Maria das Graças; Batista, Luís Roberto

    2014-11-01

    The growth of ochratoxigenic fungus and the presence of ochratoxin A (OTA) in grapes and their derivatives can be caused by a wide range of physical, chemical, and biological factors. The determination of interactions between these factors and fungal species from different climatic regions is important in designing models for minimizing the risk of OTA in wine and grape juice. This study evaluated the influence of temperature, water activity (aw), and pH on the development and production of OTA in a semisynthetic grape culture medium by Aspergillus carbonarius and Aspergillus niger strains. To analyze the growth conditions and production of OTA, an experimental design was conducted using response surface methodology as a tool to assess the effects of these abiotic variables on fungal behavior. A. carbonarius showed the highest growth at temperatures from 20 to 33°C, aw between 0.95 and 0.98, and pH levels between 5 and 6.5. Similarly, for A. niger, temperatures between 24 and 37°C, aw greater than 0.95, and pH levels between 4 and 6.5 were optimal. The greatest toxin concentrations for A. carbonarius and A. niger (10 μg/g and 7.0 μg/g, respectively) were found at 15°C, aw 0.99, and pH 5.35. The lowest pH was found to contribute to greater OTA production. These results show that the evaluated fungi are able to grow and produce OTA in a wide range of temperature, aw, and pH. However, the optimal conditions for toxin production are generally different from those optimal for fungal growth. The knowledge of optimal conditions for fungal growth and production of OTA, and of the stages of cultivation in which these conditions are optimal, allows a more precise assessment of the potential risk to health from consumption of products derived from grapes.

  20. The stability of water- and fat-soluble vitamin in dentifrices according to pH level and storage type.

    Science.gov (United States)

    Park, Jung-Eun; Kim, Ki-Eun; Choi, Yong-Jun; Park, Yong-Duk; Kwon, Ha-Jeong

    2016-02-01

    The purpose of this study is to evaluate the vitamin stabilities in dentifrices by analyzing various vitamins according to the level and storage temperature. The stabilities of water- and fat-soluble vitamins were investigated in buffer solution at different pH values (4, 7, 8, 10 and 11) for 14 days and in dentifrices at different pH (7 and 10) for 5 months at two temperature conditions (room and refrigeration temperature) by analyzing the remaining amounts using HPLC methods. In the buffer solution, the stability of vitamins B1 , B6 and C was increased as the pH values increased. Vitamins E and K showed poor stability at pH 4, and vitamin B3 showed poor stability at pH 11. In dentifrices, the storage temperature highly influenced vitamin stability, especially vitamins C and E, but the stabilities of vitamins B1 and C according to pH values did not correspond to the buffer solution tests. Vitamin B group was relatively stable in dentifrices, but vitamin C completely disappeared after 5 months. Vitamin K showed the least initial preservation rates. Vitamins were not detected in commercial dentifrices for adults and detected amounts were less than the advertised contents in dentifrices for children.

  1. Wide pH range for fluoride removal from water by MHS-MgO/MgCO₃ adsorbent: kinetic, thermodynamic and mechanism studies.

    Science.gov (United States)

    Zhang, Kaisheng; Wu, Shibiao; Wang, Xuelong; He, Junyong; Sun, Bai; Jia, Yong; Luo, Tao; Meng, Fanli; Jin, Zhen; Lin, Dongyue; Shen, Wei; Kong, Lingtao; Liu, Jinhuai

    2015-05-15

    A novel environment friendly adsorbent, micro-nano hierarchical structured flower-like MgO/MgCO3 (MHS-MgO/MgCO3), was developed for fluoride removal from water. The adsorbent was characterized and its defluoridation properties were investigated. Adsorption kinetics fitted well the pseudo-second-order model. Kinetic data revealed that the fluoride adsorption was rapid, more than 83-90% of fluoride could be removed within 30 min, and the adsorption equilibrium was achieved in the following 4 h. The fluoride adsorption isotherm was well described by Freundlich model. The maximum adsorption capacity was about 300 mg/g at pH=7. Moreover, this adsorbent possessed a very wide available pH range of 5-11, and the fluoride removal efficiencies even reached up to 86.2%, 83.2% and 76.5% at pH=11 for initial fluoride concentrations of 10, 20 and 30 mg/L, respectively. The effects of co-existing anions indicated that the anions had less effect on adsorption of fluoride except phosphate. In addition, the adsorption mechanism analysis revealed that the wide available pH range toward fluoride was mainly resulted from the exchange of the carbonate and hydroxyl groups on the surface of the MHS-MgO/MgCO3 with fluoride anions.

  2. Using airborne hyperspectral data to characterize the surface pH and mineralogy of pyrite mine tailings

    Science.gov (United States)

    Zabcic, N.; Rivard, B.; Ong, C.; Mueller, A.

    2014-10-01

    Acid mine drainage (AMD) is a key concern of the mining industry due to its impact on the quality of water and soils surrounding mine waste deposits. Acid mine drainage derives from the oxidation of metal sulphides, e.g. pyrite (FeS2), exposed to oxygen and water. The leachate acidity is capable of releasing heavy metals contained in the mining waste rock, which can affect water quality and lead to metal enrichment in sediments and potentially resulting in ecosystem degradation. Predicting tailings leachate pH is key to the management of sulfide-bearing mine wastes and is an emerging remote sensing application with limited studies having been realized. Such a capability would supplement traditional methods (i.e. ground surveys) that are challenging to implement due to the extent and large volume of mine waste. This study reports regional scale tailings mineral maps generated from airborne hyperspectral information of the Sotiel-Migollas complex in Spain and pinpoints sources of AMD. The extraction of spectral endmembers from imagery revealed twenty six endmembers for tailings material that represent mostly mineral mixtures. From these, eleven spectral groups were defined, each encompassing minor variations in mineral mixtures. The mineral maps resulting from the use of these endmembers for the detailed investigation of four tailings serve as indicators of the metal, sulphate, and pH levels of the AMD solution at the time of mineral precipitation. Predicted mineralogy was assessed using spectra from samples collected in the field and associated X-ray diffraction measurements. We also discuss the relative merits of the minerals maps of this study and soil leachate pH maps that we previously reported for the same locality using the same airborne data. The pH maps tend to provide predictions consistent with the mineralogy predicted from the mineral maps and the field and laboratory evidence. The pH maps offer information on the pH conditions of the tailings thus giving

  3. Atmospheric Water Harvesting: Role of Surface Wettability and Edge Effect

    KAUST Repository

    Jin, Yong

    2017-06-23

    Atmospheric water is emerging as an important potable water source. The present work experimentally and theoretically investigates water condensation and collection on flat surfaces with contrasting contact angles and contact angle hysteresis (CAH) to elucidate their roles on water mass collection efficiency. The experimental results indicate that a hydrophilic surface promotes nucleation and individual droplets growth, and a surface with a low CAH tends to let a smaller droplet to slide down, but the overall water mass collection efficiency is independent of both surface contact angle and CAH. The experimental results agree well with our theoretical calculations. During water condensation, a balance has to be struck between single droplet growth and droplet density on a surface so as to maintain a constant water droplet surface coverage ratio, which renders the role of both surface wettability and hysteresis insignificant to the ultimate water mass collection. Moreover, water droplets on the edges of a surface grow much faster than those on the non-edge areas and thus dominate the contribution to the water mass collection by the entire surface, directly pointing out the very important role of edge effect on water condensation and collection.

  4. Adsorbed water on iron surface by molecular dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, F.W.; Campos, T.M.B.; Cividanes, L.S., E-mail: flaviano@ita.br; Simonetti, E.A.N.; Thim, G.P.

    2016-01-30

    Graphical abstract: - Highlights: • We developed a new force field to describe the Fe–H{sub 2}O interaction. • We developed a new force field to describe the flexible water model at low temperature. • We analyze the orientation of water along the iron surface. • We calculate the vibrational spectra of water near the iron surface. • We found a complex relationship between water orientation and the atomic vibrational spectra at different sites of adsorption along the iron surface. - Abstract: The adsorption of H{sub 2}O molecules on metal surfaces is important to understand the early process of water corrosion. This process can be described by computational simulation using molecular dynamics and Monte Carlo. However, this simulation demands an efficient description of the surface interactions between the water molecule and the metallic surface. In this study, an effective force field to describe the iron-water surface interactions was developed and it was used in a molecular dynamics simulation. The results showed a very good agreement between the simulated vibrational-DOS spectrum and the experimental vibrational spectrum of the iron–water interface. The water density profile revealed the presence of a water double layer in the metal interface. Furthermore, the horizontal mapping combined with the angular distribution of the molecular plane allowed the analysis of the water structure above the surface, which in turn agrees with the model of the double layer on metal surfaces.

  5. Water Temperature, Specific Conductance, pH, and Dissolved-Oxygen Concentrations in the Lower White River and the Puyallup River Estuary, Washington, August-October 2002

    Science.gov (United States)

    Ebbert, James C.

    2003-01-01

    The U.S. Geological Survey, Washington State Department of Ecology, and Puyallup Tribe of Indians monitored water temperature, specific conductance, pH, and dissolved-oxygen concentrations in the White River at river miles 4.9 and 1.8 from August until mid-October 2002. Water diverted from the White River upstream from the monitoring sites into Lake Tapps is returned to the river at river mile 3.6 between the two sites. The same characteristics were measured in a cross section of the Puyallup River estuary at river mile 1.5 during high and low tides in September 2002. In late August, maximum daily water temperatures in the White River of 21.1oC (degrees Celsius) at river mile 4.9 and 19.6oC at river mile 1.8 exceeded the water-quality standard of 18oC at both monitoring sites. In mid-September, maximum daily water temperatures at river mile 4.9 exceeded the standard on 5 days. From August 2-25, water temperatures at both monitoring sites were similar and little or no water was discharged from Lake Tapps to the White River. Increases in water temperature at river mile 1.8 in late September and early October were caused by the mixing of warmer water discharged from Lake Tapps with cooler water in the White River. Specific conductance in the White River usually was lower at river mile 1.8 than at river mile 4.9 because of mixing with water from Lake Tapps, which has a lower specific conductance. Maximum values of pH in the White River at river mile 4.9 often exceeded the upper limit of the water-quality standard, 8.5 pH units, from early September until mid-October, when turbidity decreased. The pH standard was not exceeded at river mile 1.8. Dissolved-oxygen concentrations in the White River were often lower at river mile 1.8 than at river mile 4.9 because of mixing with water discharged from Lake Tapps, which has lower dissolved-oxygen concentrations. The lowest concentration of dissolved oxygen observed was 7.9 mg/L (milligrams per liter) at river mile 1.8. The

  6. Water temperature, specific conductance, pH, and dissolved-oxygen concentrations in the lower White River and the Puyallup River estuary, Washington, August-October 2002

    Science.gov (United States)

    Ebbert, James C.

    2003-01-01

    The U.S. Geological Survey, Washington State Department of Ecology, and Puyallup Tribe of Indians monitored water temperature, specific conductance, pH, and dissolved-oxygen concentrations in the White River at river miles 4.9 and 1.8 from August until mid-October 2002. Water diverted from the White River upstream from the monitoring sites into Lake Tapps is returned to the river at river mile 3.6 between the two sites. The same characteristics were measured in a cross section of the Puyallup River estuary at river mile 1.5 during high and low tides in September 2002. In late August, maximum daily water temperatures in the White River of 21.1°C (degrees Celsius) at river mile 4.9 and 19.6°C at river mile 1.8 exceeded the water-quality standard of 18°C at both monitoring sites. In mid-September, maximum daily water temperatures at river mile 4.9 exceeded the standard on 5 days. From August 2-25, water temperatures at both monitoring sites were similar and little or no water was discharged from Lake Tapps to the White River. Increases in water temperature at river mile 1.8 in late September and early October were caused by the mixing of warmer water discharged from Lake Tapps with cooler water in the White River.Specific conductance in the White River usually was lower at river mile 1.8 than at river mile 4.9 because of mixing with water from Lake Tapps, which has a lower specific conductance. Maximum values of pH in the White River at river mile 4.9 often exceeded the upper limit of the water-quality standard, 8.5 pH units, from early September until mid-October, when turbidity decreased. The pH standard was not exceeded at river mile 1.8. Dissolved-oxygen concentrations in the White River were often lower at river mile 1.8 than at river mile 4.9 because of mixing with water discharged from Lake Tapps, which has lower dissolved-oxygen concentrations. The lowest concentration of dissolved oxygen observed was 7.9 mg/L (milligrams per liter) at river mile 1.8. The

  7. 40 CFR 258.27 - Surface water requirements.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 24 2010-07-01 2010-07-01 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,...

  8. Floating Vegetated Mats For Improving Surface Water Quality

    Science.gov (United States)

    Contamination of surface and ground waters is an environmental concern. Pollution from both point and nonpoint sources can render water unsuitable for use. Surface waters of concern include streams, rivers, ponds, lakes, canals, and wastewater lagoons. Lagooned wastewater from confined animal feedi...

  9. Lithium content in potable water, surface water, ground water, and mineral water on the territory of Republic of Macedonia

    Directory of Open Access Journals (Sweden)

    Vesna Kostik

    2014-07-01

    Full Text Available The aim of this study was to determine lithium concentration in potable water, surface water, ground, and mineral water on the territory of the Republic of Macedonia. Water samples were collected from water bodies such as multiple public water supply systems located in 13 cities, wells boreholes located in 12 areas, lakes and rivers located in three different areas. Determination of lithium concentration in potable water, surface water was performed by the technique of inductively coupled plasma-mass spectrometry, while in ground water samples from wells boreholes and mineral waters with the technique of ion chromatography. The research shows that lithium concentration in potable water ranging from 0.1 to 5.2 μg/L; in surface water from 0.5 to 15.0 μg/L; ground water from wells boreholes from 16.0 to 49.1 μg/L and mineral water from 125.2 to 484.9 μg/L. Obtained values are in accordance with the relevant international values for the lithium content in water.

  10. Removal of selenium species from waters using various surface-modified natural particles and waste materials

    Energy Technology Data Exchange (ETDEWEB)

    Yigit, Nevzat O.; Tozum, Seda [Department of Environmental Engineering, Suleyman Demirel University, Isparta (Turkey)

    2012-07-15

    Waste red mud and natural pumice/volcanic slag particles were surface modified and their selenium adsorption from waters was investigated. Acid activation/heat treatment of original red mud (ORM) particles significantly increased their micropore and external surface area and cumulative volume of pores. Iron oxide coating of pumice/slags and acid activation of ORM decreased their pH{sub pzc} values and increased surface acidity. Selenite/selenate adsorption on iron oxide surfaces and acid activated red mud (AARM) was very fast with approximately first-order adsorption kinetics. Iron oxide coating of pumice/slag and acid activation of ORM particles significantly enhanced their selenite and selenate uptakes. Maximum Se adsorption capacities as high as 6.3 (mg Se/g adsorbent) were obtained by AARM. The extent of selenate uptakes by the surface modified particles was generally lower than those of selenite. Due to competition among Se species and other background water matrix for iron oxide adsorption sites, reduced selenite/selenate uptakes were found in natural water compared to single solute tests. Higher Se uptakes by iron oxide surfaces were found at pH 7.5 compared to pH 8.9, due to increased electrostatic repulsion among iron oxides and Se species at higher pH. The most effective adsorbents among the tested 17 different particles for Se uptake were AARM and iron oxide coated pumice. Se concentrations less than drinking water standards (5-10 {mu}g/L) can be achieved by these particles. These low-cost, natural, or recyclable waste particles appear to be promising adsorbents for Se removal after their surface modification. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. UV Light Inactivation of Human and Plant Pathogens in Unfiltered Surface Irrigation Water

    Science.gov (United States)

    Jones, Lisa A.; Worobo, Randy W.

    2014-01-01

    Fruit and vegetable growers continually battle plant diseases and food safety concerns. Surface water is commonly used in the production of fruits and vegetables and can harbor both human- and plant-pathogenic microorganisms that can contaminate crops when used for irrigation or other agricultural purposes. Treatment methods for surface water are currently limited, and there is a need for suitable treatment options. A liquid-processing unit that uses UV light for the decontamination of turbid juices was analyzed for its efficacy in the treatment of surface waters contaminated with bacterial or oomycete pathogens, i.e., Escherichia coli, Salmonella enterica, Listeria monocytogenes, Clavibacter michiganensis subsp. michiganensis, Pseudomonas syringae pv. tomato, and Phytophthora capsici. Five-strain cocktails of each pathogen, containing approximately 108 or 109 CFU/liter for bacteria or 104 or 105 zoospores/liter for Ph. capsici, were inoculated into aliquots of two turbid surface water irrigation sources and processed with the UV unit. Pathogens were enumerated before and after treatment. In general, as the turbidity of the water source increased, the effectiveness of the UV treatment decreased, but in all cases, 99.9% or higher inactivation was achieved. Log reductions ranged from 10.0 to 6.1 and from 5.0 to 4.2 for bacterial pathogens and Ph. capsici, respectively. PMID:24242253

  12. UV light inactivation of human and plant pathogens in unfiltered surface irrigation water.

    Science.gov (United States)

    Jones, Lisa A; Worobo, Randy W; Smart, Christine D

    2014-02-01

    Fruit and vegetable growers continually battle plant diseases and food safety concerns. Surface water is commonly used in the production of fruits and vegetables and can harbor both human- and plant-pathogenic microorganisms that can contaminate crops when used for irrigation or other agricultural purposes. Treatment methods for surface water are currently limited, and there is a need for suitable treatment options. A liquid-processing unit that uses UV light for the decontamination of turbid juices was analyzed for its efficacy in the treatment of surface waters contaminated with bacterial or oomycete pathogens, i.e., Escherichia coli, Salmonella enterica, Listeria monocytogenes, Clavibacter michiganensis subsp. michiganensis, Pseudomonas syringae pv. tomato, and Phytophthora capsici. Five-strain cocktails of each pathogen, containing approximately 10(8) or 10(9) CFU/liter for bacteria or 10(4) or 10(5) zoospores/liter for Ph. capsici, were inoculated into aliquots of two turbid surface water irrigation sources and processed with the UV unit. Pathogens were enumerated before and after treatment. In general, as the turbidity of the water source increased, the effectiveness of the UV treatment decreased, but in all cases, 99.9% or higher inactivation was achieved. Log reductions ranged from 10.0 to 6.1 and from 5.0 to 4.2 for bacterial pathogens and Ph. capsici, respectively.

  13. Influence of microsprinkler irrigation amount on water, soil, and pH profiles in a coastal saline soil.

    Science.gov (United States)

    Chu, Linlin; Kang, Yaohu; Wan, Shuqin

    2014-01-01

    Microsprinkler irrigation is a potential method to alleviate soil salinization. After conducting a homogeneous, highly saline, clayey, and coastal soil from the Bohai Gulf in northern China in a column experiment, the results show that the depth of the wetting front increased as the water amount applied increased, low-salinity and low-SAR enlarged after irrigation and water redistribution, and the soil pH increased with an increase in irrigation amount. We concluded that a water amount of 207 mm could be used to reclaim the coastal saline soil in northern China.

  14. Simulation programs for ph.D. study of analysis, modeling and optimum design of solar domestic hot water systems

    Energy Technology Data Exchange (ETDEWEB)

    Lin Qin

    1998-12-31

    The design of solar domestic hot water (DHW) systems is a complex process, due to characteristics inherent in the solar heating technology. Recently, computer simulation has become a widely used technique to improve the understanding of the thermal processes in such systems. One of the main objects of the Ph.D. study of `Analysis, Modelling and optimum Design of Solar Domestic Hot Water Systems` is to develop and verify programs for carrying out the simulation and evaluation of the dynamic performance of solar DHW systems. During this study, simulation programs for hot water distribution networks and for certain types of solar DHW systems were developed. (au)

  15. Influence of Microsprinkler Irrigation Amount on Water, Soil, and pH Profiles in a Coastal Saline Soil

    Directory of Open Access Journals (Sweden)

    Linlin Chu

    2014-01-01

    Full Text Available Microsprinkler irrigation is a potential method to alleviate soil salinization. After conducting a homogeneous, highly saline, clayey, and coastal soil from the Bohai Gulf in northern China in a column experiment, the results show that the depth of the wetting front increased as the water amount applied increased, low-salinity and low-SAR enlarged after irrigation and water redistribution, and the soil pH increased with an increase in irrigation amount. We concluded that a water amount of 207 mm could be used to reclaim the coastal saline soil in northern China.

  16. Fluorine uptake into the human enamel surface from fluoride-containing sealing materials during cariogenic pH cycling

    Energy Technology Data Exchange (ETDEWEB)

    Yasuhiro, Matsuda, E-mail: matsuda@den.hokudai.ac.jp [Department of Restorative Dentistry, Graduate School of Dental Medicine Hokkaido University (Japan); Katsushi, Okuyama [Department of Restorative Dentistry, Graduate School of Dental Medicine Hokkaido University (Japan); Hiroko, Yamamoto [Graduate School of Dentistry, Osaka University (Japan); Hisanori, Komatsu [Department of Restorative Dentistry, Graduate School of Dental Medicine Hokkaido University (Japan); Masashi, Koka; Takahiro, Sato [Takasaki Advanced Radiation Research Institute, JAEA (Japan); Naoki, Hashimoto; Saiko, Oki; Chiharu, Kawamoto; Hidehiko, Sano [Department of Restorative Dentistry, Graduate School of Dental Medicine Hokkaido University (Japan)

    2015-04-01

    To prevent the formation of caries and reduce dentin hypersensitivity, sealing materials, either with or without fluoride, are generally applied on the tooth in clinical practice. Application of fluoride-free sealing materials results in the formation of an acid-resistant layer on the tooth surface. On the other hand, fluoride-containing sealing materials might not only form an acid-resistant layer but could possibly further provide fluoride to enhance remineralization and reduce demineralization. In this study, the demineralization prevention ability and fluorine uptake rate in human enamel of fluoride-containing sealing materials [“MS coats F” (MSF)] and fluoride-free sealing materials (“hybrid coats 2” [HI]) were evaluated using an automatic pH cycling system. Each material was applied to the original tooth surface, the cut surfaces were covered with sticky wax, and the automatic pH-cycling system simulated daily acid changes (pH 6.8–4.5) occurring in the oral cavity for 4 weeks. Caries progression was analyzed using transverse microradiography (TMR) taken pre and post the 4 weeks of pH cycling. The fluorine and calcium distributions in the carious lesion in each specimen were evaluated using the proton-induced gamma emission (PIGE) and proton-induced X-ray (PIXE) techniques, respectively. TMR analysis showed that both MSF and HI had a caries-preventing effect after 4 weeks of pH cycling. PIGE/PIXE analysis demonstrated that only MSF resulted in fluoride uptake in the enamel surface. Therefore, MSF can help to form an acid-resistant layer and provide fluoride to the enamel surface. The presence of fluoride on the enamel surface suggested that MSF could prevent demineralization, even if the acid-resistant layer was removed, in clinical settings. The data obtained using the PIGE and PIXE techniques are useful for understanding the benefits of the use of a fluoride-containing sealing material for preventing caries.

  17. How to repel hot water from a superhydrophobic surface?

    KAUST Repository

    Yu, Zhejun

    2014-01-01

    Superhydrophobic surfaces, with water contact angles greater than 150° and slide angles less than 10°, have attracted a great deal of attention due to their self-cleaning ability and excellent water-repellency. It is commonly accepted that a superhydrophobic surface loses its superhydrophobicity in contact with water hotter than 50 °C. Such a phenomenon was recently demonstrated by Liu et al. [J. Mater. Chem., 2009, 19, 5602], using both natural lotus leaf and artificial leaf-like surfaces. However, our work has shown that superhydrophobic surfaces maintained their superhydrophobicity, even in water at 80 °C, provided that the leaf temperature is greater than that of the water droplet. In this paper, we report on the wettability of water droplets on superhydrophobic thin films, as a function of both their temperatures. The results have shown that both the water contact and slide angles on the surfaces will remain unchanged when the temperature of the water droplet is greater than that of the surface. The water contact angle, or the slide angle, will decrease or increase, however, with droplet temperatures increasingly greater than that of the surfaces. We propose that, in such cases, the loss of superhydrophobicity of the surfaces is caused by evaporation of the hot water molecules and their condensation on the cooler surface. © 2014 the Partner Organisations.

  18. Effect of concentration and pH on the surface-enhanced Raman scattering of captopril on nano-colloidal silver surface

    Science.gov (United States)

    Gao, Junxiang; Gu, Huaimin; Liu, Fangfang; Dong, Xiao; Xie, Min; Hu, Yongjun

    2011-07-01

    In this report, Raman and surface-enhanced Raman scattering (SERS) spectra of captopril are studied in detail. Herein, the Raman bands are assigned by the density functional theory (DFT) calculations and potential energy distributions (PED) based on internal coordinates of the molecule, which are found to be in good agree with the experimental values. Furthermore, the concentration and pH dependence of the SERS intensity of the molecule is discussed. By analyzing the intensities variation of SERS bands of the different concentrations of captopril solution, it can be concluded that the molecules orientation adsorbed on the silver nanoparticles surface change with the change of the concentrations. The variation of SERS spectra of captopril with the change of pH suggests that the interaction among the adsorbates with Ag cluster depend on the protonated state of the adsorbate and the aggregation of silver nanoparticles.

  19. Sticky water surfaces: Helix-coil transitions suppressed in a cell-penetrating peptide at the air-water interface

    Science.gov (United States)

    Schach, Denise; Globisch, Christoph; Roeters, Steven J.; Woutersen, Sander; Fuchs, Adrian; Weiss, Clemens K.; Backus, Ellen H. G.; Landfester, Katharina; Bonn, Mischa; Peter, Christine; Weidner, Tobias

    2014-12-01

    GALA is a 30 amino acid synthetic peptide consisting of a Glu-Ala-Leu-Ala repeat and is known to undergo a reversible structural transition from a disordered to an α-helical structure when changing the pH from basic to acidic values. In its helical state GALA can insert into and disintegrate lipid membranes. This effect has generated much interest in GALA as a candidate for pH triggered, targeted drug delivery. GALA also serves as a well-defined model system to understand cell penetration mechanisms and protein folding triggered by external stimuli. Structural transitions of GALA in solution have been studied extensively. However, cell penetration is an interfacial effect and potential biomedical applications of GALA would involve a variety of surfaces, e.g., nanoparticles, lipid membranes, tubing, and liquid-gas interfaces. Despite the apparent importance of interfaces in the functioning of GALA, the effect of surfaces on the reversible folding of GALA has not yet been studied. Here, we use sum frequency generation vibrational spectroscopy (SFG) to probe the structural response of GALA at the air-water interface and IR spectroscopy to follow GALA folding in bulk solution. We combine the SFG data with molecular dynamics simulations to obtain a molecular-level picture of the interaction of GALA with the air-water interface. Surprisingly, while the fully reversible structural transition was observed in solution, at the water-air interface, a large fraction of the GALA population remained helical at high pH. This "stickiness" of the air-water interface can be explained by the stabilizing interactions of hydrophobic leucine and alanine side chains with the water surface.

  20. Structure and reactivity of water at biomaterial surfaces.

    Science.gov (United States)

    Vogler, E A

    1998-02-01

    Molecular self association in liquids is a physical process that can dominate cohesion (interfacial tension) and miscibility. In water, self association is a powerful organizational force leading to a three-dimensional hydrogen-bonded network (water structure). Localized perturbations in the chemical potential of water as by, for example, contact with a solid surface, induces compensating changes in water structure that can be sensed tens of nanometers from the point of origin using the surface force apparatus (SFA) and ancillary techniques. These instruments reveal attractive or repulsive forces between opposing surfaces immersed in water, over and above that anticipated by continuum theory (DLVO), that are attributed to a variable density (partial molar volume) of a more-or-less ordered water structure, depending on the water wettability (surface energy) of the water-contacting surfaces. Water structure at surfaces is thus found to be a manifestation of hydrophobicity and, while mechanistic/theoretical interpretation of experimental results remain the subject of some debate in the literature, convergence of experimental observations permit, for the first time, quantitative definition of the relative terms 'hydrophobic' and 'hydrophilic'. In particular, long-range attractive forces are detected only between surfaces exhibiting a water contact angle theta > 65 degrees (herein defined as hydrophobic surfaces with pure water adhesion tension tau O = gamma O cos theta 30 dyn/cm). These findings suggest at least two distinct kinds of water structure and reactivity: a relatively less-dense water region against hydrophobic surfaces with an open hydrogen-bonded network and a relatively more-dense water region against hydrophilic surfaces with a collapsed hydrogen-bonded network. Importantly, membrane and SFA studies reveal a discrimination between biologically-important ions that preferentially solubilizes divalent ions in more-dense water regions relative to less

  1. Distribution of {sup 129}I in terrestrial surface water environments

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xuegao [State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing 210098 (China); College of Hydrology and Water Resources, Hohai University, Nanjing (China); Gong, Meng [College of Hydrology and Water Resources, Hohai University, Nanjing (China); Yi, Peng, E-mail: pengyi1915@163.com [State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing 210098 (China); College of Hydrology and Water Resources, Hohai University, Nanjing (China); Aldahan, Ala [Department of Earth Sciences, Uppsala University, Uppsala (Sweden); Department of Geology, United Arab Emirates University, Al Ain (United Arab Emirates); Yu, Zhongbo [State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing 210098 (China); College of Hydrology and Water Resources, Hohai University, Nanjing (China); Possnert, Göran [Tandem Laboratory, Uppsala University, Uppsala (Sweden); Chen, Li [State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing 210098 (China); College of Hydrology and Water Resources, Hohai University, Nanjing (China)

    2015-10-15

    The global distribution of the radioactive isotope iodine-129 in surface waters (lakes and rivers) is presented here and compared with the atmospheric deposition and distribution in surface marine waters. The results indicate relatively high concentrations in surface water systems in close vicinity of the anthropogenic release sources as well as in parts of Western Europe, North America and Central Asia. {sup 129}I level is generally higher in the terrestrial surface water of the Northern hemisphere compared to the southern hemisphere. The highest values of {sup 129}I appear around 50°N and 40°S in the northern and southern hemisphere, separately. Direct gaseous and marine atmospheric emissions are the most likely avenues for the transport of {sup 129}I from the sources to the terrestrial surface waters. To apply iodine-129 as process tracer in terrestrial surface water environment, more data are needed on {sup 129}I distribution patterns both locally and globally.

  2. Water content distribution in the surface layer of Maoping slope

    Institute of Scientific and Technical Information of China (English)

    LIU Yuewu; CHEN Huixin; LIU Qingquan; GONG Xin; ZHANG Dawei; LI Lianxiang

    2005-01-01

    The water content distribution in the surface layer of Maoping slope has been studied by testing the water content at 31 control sites. The water content profiles at these sites have also been determined. The water content distributions at different segments have been obtained by using the Kriging method of geostatistics. By comparing the water content distributions with the landform of the slope, it was shown that the water content is closely dependent on the landform of the slope. The water content distribution in the surface layer provided a fundamental basis for landslide predication and treatment.

  3. Partial pressure (or fugacity) of carbon dioxide, dissolved inorganic carbon, pH, alkalinity, temperature, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from WEATHERBIRD II in the Coastal Waters of Florida and Gulf of Mexico from 2008-08-11 to 2011-06-30 (NCEI Accession 0144622)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0144622 includes Surface underway data collected from WEATHERBIRD II in the Coastal Waters of Florida and Gulf of Mexico from 2008-08-11 to...

  4. The effect of prolonged immersion of giomer bulk-fill composite resin on the pH value of artificial saliva and resin surface roughness

    Science.gov (United States)

    Ratna, A. A.; Triaminingsih, S.; Eriwati, Y. K.

    2017-08-01

    This study aimed to determine the effect of immersion time on the surface roughness of Giomer Bulk-Fill composite resin and on the pH value of artificial saliva. Sixty-three specimens were divided into nine groups and immersed in artificial saliva with pH values of 7, 5.5, and 4.5 for 1 hour, 24 hours, and 72 hours at 37 °C. The changes in artificial saliva pH were measured using a pH meter and the surface roughness was measured using a surface roughness tester. Longer immersion time increases the pH of artificial saliva and the surface roughness of Giomer Bulk-Fill composite resin.

  5. Gas Surface Interactions Occurring on Materials Within Ultrahigh Vacuum. Ph.D. Thesis - va. Polytechnic Inst.

    Science.gov (United States)

    Outlaw, R. A.

    1972-01-01

    The physical adsorption of nitrogen on the chemically cleaned surfaces of Pyrex, 347 stainless steel and polycrystalline nickel was investigated over the pressure range 1 x 10 to the minus 12th power to 3 x 10 to the minus 7th power torr and for temperatures 77.4 and 87.4 K. The adsorption data were linearized by the Dubinin-Radushkevich equation. The metal surfaces were cleaned by electron impact desorption (EID) and the desorbed gases analyzed by mass spectrometry. Work function measurements were also used to indicate changes in the surface condition following an EID dose. At least a monolayer of gas was observed to desorb from the metal surfaces. The isotherms revealed that the metal surfaces were very heterogeneous and that the Pyrex surface had been leached. The calculated isosteric heats of adsorption indicated that the relative order of the physical binding of nitrogen to the solids was 347 stainless steel Pyrex nickel. A relationship was observed to exist in the dynamic technique between the equilibration time and the pressure above the absorbed layer. The slope of the log-log plot of these parameters was found to be sensitive to the surface heterogeneity and may be related to the activation energy for surface diffusion of physically absorbed molecules.

  6. Section 11: Surface Water Pathway - Likelihood of Release

    Science.gov (United States)

    Surface water releases can include the threat to targets from overland flow of hazardous substances and from flooding or the threat from the release of hazardous substances to ground water and the subsequent discharge of contaminated ground w

  7. Ascii grids of predicted pH in depth zones used by domestic and public drinking water supply depths, Central Valley, California

    Science.gov (United States)

    Zamora, Celia; Nolan, Bernard T.; Gronberg, JoAnn M.

    2017-01-01

    The ascii grids associated with this data release are predicted distributions of continuous pH at the drinking water depth zones in the groundwater of Central Valley, California. The two prediction grids produced in this work represent predicted pH at the domestic supply and public supply drinking water depths, respectively and are bound by the alluvial boundary that defines the Central Valley. A depth of 46 m was used to stratify wells into the shallow and deep aquifer and were derived from depth percentiles associated with domestic and public supply in previous work by Burow et al. (2013). In this work, the median well depth categorized as domestic supply was 30 meters below land surface and the median well depth categorized as public supply is 100 meters below land surface. Prediction grids were created using prediction modeling methods, specifically Boosted Regression Trees (BRT) with a gaussian error distribution within a statistical learning framework within R's computing framework (http://www.r-project.org/). The statistical learning framework seeks to maximize the predictive performance of machine learning methods through model tuning by cross validation. The response variable was measured pH from 1337 wells, and was compiled from two sources: US Geological Survey (USGS) National Water Information System (NWIS) Database (all data are publicly available from the USGS: http://waterdata.usgs.gov/ca/nwis/nwis) and the California State Water Resources Control Board Division of Drinking Water (SWRCB-DDW) database (water quality data are publicly available from the SWRCB: http://www.waterboards.ca.gov/gama/geotracker_gama.shtml). Only wells with measured pH and well depth data were selected, and for wells with multiple records, only the most recent sample in the period 1993-2014 was used. A total of 1003 wells (training dataset) were used to train the BRT model and 334 wells (hold-out dataset) were used to validate the prediction model. The training r-squared was

  8. Biofilm development on metal surfaces in tropical marine waters

    Digital Repository Service at National Institute of Oceanography (India)

    DeSouza, F.P.; Bhosle, N.B.

    environments. However, little is known about biofilm bacteria developed on metal surfaces, especially immersed in tropical marine waters. Similarly, not much is known about the nature of organic matter deposited on the surfaces over the period of immersion...

  9. The glass-liquid transition of water on hydrophobic surfaces.

    Science.gov (United States)

    Souda, Ryutaro

    2008-09-28

    Interactions of thin water films with surfaces of graphite and vitrified room-temperature ionic liquid [1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF(6)])] were investigated using time-of-flight secondary ion mass spectrometry as a function of temperature and annealing time to elucidate the glass-liquid transition of water at the molecular level. Surface diffusion of water occurs at temperatures higher than 120 K, thereby forming three-dimensional clusters (a two-dimensional layer) on the [bmim][PF(6)] (graphite) surface. The hydrophobic effect of the surface decreases with increasing coverage of water; the bulklike properties evolve up to 40 ML, as evidenced by the occurrence of film dewetting at around the conventional glass transition temperature (140 K). Results also showed that aging is necessary for the water monolayer (a 40 ML water film) to dewet the graphite ([bmim][PF(6)]) surface. The occurrence of aging is explainable by the successive evolution of two distinct liquids during the glass-liquid transition: low density liquid is followed by supercooled liquid water. The water monolayer on graphite is characterized by the preferred orientation of unpaired OH groups toward the surface; this structure is arrested during the aging time despite the occurrence of surface diffusion. However, the water monolayer formed on the [bmim][PF(6)] surface agglomerates immediately after the commencement of surface diffusion. The structure of low density liquid tends to be arrested by the attractive interaction with the neighbors.

  10. Proton Transfer Dynamics at the Membrane/Water Interface: Dependence on the Fixed and Mobile pH Buffers, on the Size and Form of Membrane Particles, and on the Interfacial Potential Barrier

    OpenAIRE

    Cherepanov, Dmitry A.; Junge, Wolfgang; Armen Y Mulkidjanian

    2004-01-01

    Crossing the membrane/water interface is an indispensable step in the transmembrane proton transfer. Elsewhere we have shown that the low dielectric permittivity of the surface water gives rise to a potential barrier for ions, so that the surface pH can deviate from that in the bulk water at steady operation of proton pumps. Here we addressed the retardation in the pulsed proton transfer across the interface as observed when light-triggered membrane proton pumps ejected or captured protons. B...

  11. The surface properties of Shewanella putrefaciens 200 and S. oneidensis MR-1: the effect of pH and terminal electron acceptors.

    Science.gov (United States)

    Furukawa, Yoko; Dale, Jason R

    2013-04-08

    We investigated the surface characteristics of two strains of Shewanella sp., S. oneidensis MR-1 and S. putrefaciens 200, that were grown under aerobic conditions as well as under anaerobic conditions with trimethylamine oxide (TMAO) as the electron acceptor. The investigation focused on the experimental determination of electrophoretic mobility (EPM) under a range of pH and ionic strength, as well as by subsequent modeling in which Shewanella cells were considered to be soft particles with water- and ion-permeable outermost layers. The soft layer of p200 is significantly more highly charged (i.e., more negative) than that of MR-1. The effect of electron acceptor on the soft particle characteristics of Shewanella sp. is complex. The fixed charge density, which is a measure of the deionized and deprotonated functional groups in the soft layer polymers, is slightly greater (i.e., more negative) for aerobically grown p200 than for p200 grown with TMAO. On the other hand, the fixed charge density of aerobically grown MR1 is slightly less than that of p200 grown with TMAO. The effect of pH on the soft particle characteristics is also complex, and does not exhibit a clear pH-dependent trend. The Shewanella surface characteristics were attributed to the nature of the outermost soft layer, the extracellular polymeric substances (EPS) in case of p200 and lypopolysaccharides (LPS) in case of MR1 which generally lacks EPS. The growth conditions (i.e., aerobic vs. anaerobic TMAO) have an influence on the soft layer characteristics of Shewanella sp. cells. Meanwhile, the clear pH dependency of the mechanical and morphological characteristics of EPS and LPS layers, observed in previous studies through atomic force microscopy, adhesion tests and spectroscopies, cannot be corroborated by the electrohydrodynamics-based soft particle characteristics which does not exhibited a clear pH dependency in this study. While the electrohydrodynamics-based soft-particle model is a useful tool

  12. Hydrogeochemical analysis and evaluation of surface water quality of Pratapgarh district, Uttar Pradesh, India

    Science.gov (United States)

    Tiwari, Ashwani Kumar; Singh, Abhay Kumar; Singh, Amit Kumar; Singh, M. P.

    2017-07-01

    The hydrogeochemical study of surface water in Pratapgarh district has been carried out to assess the major ion chemistry and water quality for drinking and domestic purposes. For this purpose, twenty-five surface water samples were collected from river, ponds and canals and analysed for pH, electrical conductivity, total dissolved solids (TDS), turbidity, hardness, major cations (Ca2+, Mg2+, Na+ and K+), major anions (HCO3 -, F-, Cl-, NO3 -, SO4 2-) and dissolved silica concentration. The analytical results show mildly acidic to alkaline nature of surface water resources of Pratapgarh district. HCO3 - and Cl- are the dominant anions, while cation chemistry is dominated by Na+ and Ca2+. The statistical analysis and data plotted on the Piper diagram reveals that the surface water chemistry is mainly controlled by rock weathering with secondary contributions from agriculture and anthropogenic sources. Ca2+-Mg2+-HCO3 -, Ca2+-Mg2+-Cl- and Na+-HCO3 --Cl- are the dominant hydrogeochemical facies in the surface water of the area. For quality assessment, values of analysed parameters were compared with Indian and WHO water quality standards, which shows that the concentrations of TDS, F-, NO3 -, Na+, Mg2+ and total hardness are exceeding the desirable limits in some water samples. Water Quality Index (WQI) is one of the most effective tools to communicate information on the quality of any water body. The computed WQI values of Pratapgarh district surface water range from 28 to 198 with an average value of 82, and more than half of the study area is under excellent to good category.

  13. The influence of seawater pH on U / Ca ratios in the scleractinian cold-water coral Lophelia pertusa

    Directory of Open Access Journals (Sweden)

    J. Raddatz

    2013-10-01

    Full Text Available The increasing pCO2 in seawater is a serious threat for marine calcifiers and alters the biogeochemistry of the ocean. Therefore, the reconstruction of past-seawater properties and their impact on marine ecosystems is an important way to investigate the underlying mechanisms and to better constrain the effects of possible changes in the future ocean. Cold-water coral (CWC ecosystems are biodiversity hotspots. Living close to aragonite-undersaturation, these corals serve as living laboratories as well as archives to reconstruct the boundary conditions of their calcification under the carbonate system of the ocean. We investigated the reef-building CWC Lophelia pertusa as a recorder of intermediate ocean seawater pH. This species-specific field calibration is based on a unique sample set of live in-situ collected L. pertusa and corresponding seawater samples. These data demonstrate that uranium speciation and skeletal incorporation for azooxanthellate scleractinian CWCs is pH dependent. However, this also indicates that internal pH up-regulation of the coral does not play a role in uranium incorporation into the majority of the skeleton of L. pertusa. This study suggests L. pertusa provides a new archive for the reconstruction of intermediate water mass pH and hence may help to constrain tipping points for ecosystem dynamics and evolutionary characteristics in a changing ocean.

  14. Conjunctive Surface Water and Groundwater Management under Climate Change

    Directory of Open Access Journals (Sweden)

    Xiaodong eZhang

    2015-09-01

    Full Text Available Climate change can result in significant impacts on regional and global surface water and groundwater resources. Using groundwater as a complimentary source of water has provided an effective means to satisfy the ever-increasing water demands and deal with surface water shortages problems due to robust capability of groundwater in responding to climate change. Conjunctive use of surface water and groundwater is crucial for integrated water resources management. It is helpful to reduce vulnerabilities of water supply systems and mitigate the water supply stress in responding to climate change. Some critical challenges and perspectives are discussed to help decision/policy makers develop more effective management and adaptation strategies for conjunctive water resources use in facing climate change under complex uncertainties.

  15. Spreading of Cholera through Surface Water

    Science.gov (United States)

    Bertuzzo, E.; Casagrandi, R.; Gatto, M.; Rodriguez-Iturbe, I.; Rinaldo, A.

    2009-12-01

    Cholera epidemics are still a major public health concern to date in many areas of the world. In order to understand and forecast cholera outbreaks, one of the most important factors is the role played by the environmental matrix in which the disease spreads. We study how river networks, acting as environmental corridors for pathogens, affect the spreading of cholera epidemics. The environmental matrix in which the disease spreads is constituted by different human communities and their hydrologic interconnections. Each community is characterized by its spatial position, population size, water resources availability and hygiene conditions. By implementing a spatially explicit cholera model we seek the effects on epidemic dynamics of: i) the topology and metrics of the pathogens pathways that connect different communities; ii) the spatial distribution of the population size; and iii) the spatial distributions and quality of surface water resources and public health conditions, and how they vary with population size. The model has been applied to study the space-time evolution of a well documented cholera epidemic occurred in the KwaZulu-Natal province of South Africa. The epidemic lasted for two years and involved about 140,000 confirmed cholera cases. The model does well in reproducing the distribution of the cholera cases during the two outbreaks as well as their spatial spreading. We further extend the model by deriving the speed of propagation of traveling fronts in the case of uniformly distributed systems for different topologies: one and two dimensional lattices and river networks. The derivation of the spreading celerity proves instrumental in establishing the overall conditions for the relevance of spatially explicit models. The conditions are sought by comparison between spreading and disease timescales. Consider a cholera epidemic that starts from a point and spreads throughout a finite size system, it is possible to identify two different timescales: i

  16. Region 9 Surface Water Intakes (SDWIS)

    Data.gov (United States)

    U.S. Environmental Protection Agency — EPAâ??s Safe Drinking Water Information System (SDWIS) databases store information about drinking water. The federal version (SDWIS/FED) stores the information EPA...

  17. The effect of pH, fluoride and tribocorrosion on the surface properties of dental archwires.

    Science.gov (United States)

    Močnik, Petra; Kosec, Tadeja; Kovač, Janez; Bizjak, Milan

    2017-09-01

    Nickel-titanium and stainless steel are the most commonly used alloys for orthodontic treatments. Even though both are known to be resistant to corrosion, there are circumstances that can lead to undesired situations, like localized types of corrosion attack, wear during sliding of an archwire though brackets and breakdowns due to iatrogenic causes. The aim of this research was to analyse the influence of environmental effects on the corrosion and tribocorrosion properties of NiTi and stainless steel dental alloys. The effects of pH and fluorides on the electrochemical properties were studied using the cyclic potentiodynamic technique. The migration of ions from the alloy into saliva during exposure to saliva with and without the presence of wear was analysed using ICP-MS analyses. Auger spectroscopy was used to study the formation of a passive oxide layer on different dental alloys. It was found that lowering the pH preferentially affects the corrosion susceptibility of NiTi alloys, whereas stainless steel dental archwires are prone to local types of corrosion. The NiTi alloy is not affected by smaller increases of fluoride ions up to 0.024M, while at 0.076M (simulating the use of toothpaste) the properties are affected. A leaching test during wear-assisted corrosion showed that the concentrations of Ni ions released into the saliva exceeded the limit value of 0.5μg/cm(2)/week. The oxide films on the NiTi and stainless steel alloys after the tribocorrosion experiment were thicker than those exposed to saliva only. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. COMMUNITY PARTICIPATION IN SURFACE WATER HARVESTING ...

    African Journals Online (AJOL)

    USER

    2014-11-25

    Nov 25, 2014 ... There is seasonal water scarcity in Marigat Division and the water demand has been ... with improved storage and rainwater harvesting methods. Such water can be ..... in the planning process and decision making and this ... The organizations support the community ... systems for domestic uses in urban.

  19. Differences in the Effect of Coal Pile Runoff (Low pH, High Metal Concentrations) Versus Natural Carolina Bay Water (Low pH, Low Metal Concentrations) on Plant Condition and Associated Bacterial Epiphytes of Salvinia minima.

    Science.gov (United States)

    Lindell, A H; Tuckfield, R C; McArthur, J V

    2016-05-01

    Numerous wetlands and streams have been impacted by acid mine drainage (AMD) resulting in lowered pH and increased levels of toxic heavy metals. Remediation of these contaminated sites requires knowledge on the response of microbial communities (especially epiphytic) and aquatic plants to these altered environmental conditions. We examined the effect of coal pile runoff waters as an example of AMD in contrast to natural water from Carolina Bays with low pH and levels of metals on Salvinia minima, a non-native, metal accumulating plant and associated epiphytic bacteria. Treatments included water from two Carolina Bays, one AMD basin and Hoagland's Solution at two pH levels (natural and adjusted to 5.0-5.5). Using controlled replicated microcosms (N = 64) we determined that the combination of low pH and high metal concentrations has a significant negative impact (p epiphytes. Solution metal concentrations dropped indicating removal from solution by S. minima in all microcosms.

  20. Posteruptive impacts of pyroclastic deposits from basaltic andesite stratovolcanoes on surface water composition

    Science.gov (United States)

    Genareau, K.; Cronin, S. J.; Stewart, C.; Bhattacharyya, S.; Donahoe, R.

    2016-05-01

    Volcanic ash deposition following explosive eruptions can pose significant hazards for water quality, human health, agriculture, and infrastructure functionality. Many studies have examined how fresh ash deposition may lower the pH of, and introduce a range of potentially toxic elements into, exposed surface waters. However, no study has yet determined the effects on water composition as a result of mechanical pyroclast disaggregation and production of new fresh particle surfaces and increasingly fine grained particles. Such disaggregation could result from natural posteruptive processes such as debris avalanches, lahars, or fluvial/aeolian transport and human activities such as cleanup efforts or mining of pyroclastic deposits. The posteruption time scales of pyroclast disaggregation may vary from months in moist tropical or temperate environments to years or decades in arid settings. Here we show, for the first time in experimental studies, that mechanical milling of pyroclasts will introduce a range of elements into exposed waters, including Al, which can be toxic at elevated levels, and Na, which increases the electrical conductivity of solutions. The pH of leaching solutions also increases by several log units. Such dramatic changes on the experimental scale may have implications for surface water composition in posteruptive settings, necessitating longer-term risk assessments for ecosystem health and consideration of the role of pyroclastic deposits in element cycling in volcanically active regions.

  1. An ontology design pattern for surface water features

    Science.gov (United States)

    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.

  2. Adsorption mechanism of water molecule on goethite (010) surface

    Science.gov (United States)

    Xiu, Fangyuan; Zhou, Long; Xia, Shuwei; Yu, Liangmin

    2016-12-01

    Goethite widely exists among ocean sediments; it plays an important role in fixing heavy metals and adsorbing organic contaminants. So the understanding of the adsorbing process of water molecule on its surface will be very helpful to further reveal such environmental friendly processes. The configuration, electronic properties and interaction energy of water molecules adsorbed on pnma goethite (010) surface were investigated in detail by using density functional theory on 6-31G (d,p) basis set and projector- augment wave (PAW) method. The mechanism of the interaction between goethite surface and H2O was proposed. Despite the differences in total energy, there are four possible types of water molecule adsorption configurations on goethite (010) surface (Aa, Ab, Ba, Bb), forming coordination bond with surface Fe atom. Results of theoretical modeling indicate that the dissociation process of adsorbed water is an endothermic reaction with high activation energy. The dissociation of adsorbed water molecule is a proton transportation process between water's O atoms and surface. PDOS results indicate that the bonding between H2O and (010) surface is due to the overlapping of water's 2p orbitals and Fe's 3d orbitals. These results clarify the mechanism on how adsorbed water is dissociated on the surface of goethite and potentially provide useful information of the surface chemistry of goethite.

  3. Infiltration of pesticides in surface water into nearby drinking water supply wells

    DEFF Research Database (Denmark)

    Malaguerra, Flavio; Albrechtsen, Hans-Jørgen; Binning, Philip John

    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...

  4. Early warning smartphone diagnostics for water security and analysis using real-time pH mapping

    Science.gov (United States)

    Hossain, Md. Arafat; Canning, John; Ast, Sandra; Rutledge, Peter J.; Jamalipour, Abbas

    2015-12-01

    Early detection of environmental disruption, unintentional or otherwise, is increasingly desired to ensure hazard minimization in many settings. Here, using a field-portable, smartphone fluorimeter to assess water quality based on the pH response of a designer probe, a map of pH of public tap water sites has been obtained. A custom designed Android application digitally processed and mapped the results utilizing the global positioning system (GPS) service of the smartphone. The map generated indicates no disruption in pH for all sites measured, and all the data are assessed to fall inside the upper limit of local government regulations, consistent with authority reported measurements. This implementation demonstrates a new security concept: network environmental forensics utilizing the potential of novel smartgrid analysis with wireless sensors for the detection of potential disruption to water quality at any point in the city. This concept is applicable across all smartgrid strategies within the next generation of the Internet of Things and can be extended on national and global scales to address a range of target analytes, both chemical and biological.

  5. Optimized coagulation of high alkalinity, low temperature and particle water: pH adjustment and polyelectrolytes as coagulant aids.

    Science.gov (United States)

    Yu, Jianfeng; Wang, Dongsheng; Yan, Mingquan; Ye, Changqing; Yang, Min; Ge, Xiaopeng

    2007-08-01

    The Yellow River in winter as source water is characterized as high alkalinity, low temperature and low particle concentrations, which have brought many difficulties to water treatment plants. This study fully examines the optimized coagulation process of the Yellow River by conventional and pre-polymerized metal coagulants, pH adjustment and polyelectrolytes as the primary coagulants or coagulant aids. For all the metal coagulants, polyaluminum chlorides are superior to traditional metal coagulants due to their stable polymeric species and low consumption of alkalinity. The removal of natural organic matter by monomeric metal coagulants can be improved through pH adjustment, which is in accordance with the higher concentration of polymeric species formed at corresponding pH value. With the addition of polyelectrolytes as coagulant aids, the coagulation performance is significantly improved. The effective removal of dissolved organic matter is consistent with high charge density, while molecular weight is relatively important for removing particles, which is consistent with polyelectrolytes as primary coagulants. These results suggest that the coagulation mechanisms in the removal of dissolved organic matter and particles are different, which may be exploited for optimized coagulation for the typical source water in practice.

  6. Surface modification of a zeolite and the influence of pH and ionic strength on the desorption of an amine

    Directory of Open Access Journals (Sweden)

    JOVAN LEMIC

    2006-11-01

    Full Text Available The adsorption of stearyldimethylbenzylammonium chloride (SDBAC on the clinoptilolite–heulandite rich tuff in dependence on the applied temperature was studied. The maximal amount of sorbed SDBAC was 123 mmol/kg in the case of thermally treated zeolite tuff (100 °C and a warm surfactant solution (80 °C. The amount and properties of water adsorbed on the organo-zeolite (OZ as well as the bonding between the organic species and the zeolite were investigated by DTA, TG, DTG and IR analyses. During gradual heating in an oxidizing atmosphere, the adsorbed organic material was oxidized, giving rise to significant exothermic peaks. The adsorption of water vapor decreased with increasing SDBAC loading up to 75 mmol/kg of zeolite, which can be ascribed to an intensification of the hydrophobic characteristics of the surface. With loadings above the 75 mmol/kg, the adsorption of water vapor increased. Desorption of SDBAC from the organo-zeolite under environmentally relevant conditions: distilled water, pH 3 and 10 buffers, as well as aqueous NaCl and CaCl2 solutions, was investigated. OZs with loadings up to their external cation exchange capacity value (75 mmol/kg were stable under all of the applied conditions.

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

    Science.gov (United States)

    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.

  8. Realization of National Programme of Municipal Wastewater Treatment and the quality of surface water in Poland

    Directory of Open Access Journals (Sweden)

    Sylwia Myszograj

    2012-09-01

    Full Text Available One of the aims of improving water quality, resulting directly from the Water Framework Directive 2000/60/EC, is to achieve in 2015, at least good status for all waters in the country. Following the adoption by Poland of the Water Framework Directive assessment of the economic and general cleanliness of water was replaced by an assessment of ecological status. In this way, the analysis of water status shall be treated as not only economic resources, but primarily as part of the ecosystem. The most important from the standpoint of human health protection, is the quality of water intended for human consumption.In the document „The purity of rivers based on the results of tests carried out within the national environmental monitoring in 2007–2009” is given that: – only 10.6% of the surface of flowing water meets the requirements of collective waters used for water supply for drinking, – up 28.7% of the length of monitored water is too polluted for them mildest demands posed conditioned needs of the economy. The decrease in water quality was affected by the physico-chemical pollutants such as pH, total suspension, manganese, polycyclic aromatic hydrocarbons (PAHs, CODCr, BOD5 and TOC. Large impact on reducing water quality category also had microbial contamination, the number of fecal coliform bacteria, fecal streptococci and total coliforms.

  9. Effect of ethanol and pH on the adsorption of acetaminophen (paracetamol) to high surface activated charcoal, in vitro studies

    DEFF Research Database (Denmark)

    Høgberg, Lotte Christine Groth; Angelo, Helle R; Christophersen, A Bolette

    2002-01-01

    the maximum adsorption capacity for paracetamol for two types of high surface-activated charcoal [Carbomix and Norit Ready-To-Use (not yet registered trademark in Denmark) both from Norit Cosmara, Amersfoort, The Netherlands] in simulated in vivo environments: At pH 1.2 (gastric environment), at pH 7...

  10. Adsorption and nanowear properties of bovine submaxillary mucin films on solid surfaces: Influence of solution pH and substrate hydrophobicity

    DEFF Research Database (Denmark)

    Sotres, Javier; Madsen, Jan Busk; Arnebrant, Thomas;

    2014-01-01

    The adsorption and mechanical stability of bovine submaxillary mucins (BSM) films at solid-liquid interfaces were studied with respect to both substrate hydrophobicity and solution pH. Dynamic light scattering revealed a single peak distribution in neutral aqueous solution (pH 7.4) and a small...... fraction with enhanced aggregation was observed in acidic solution (pH 3.8). Both substrate hydrophobicity and solution pH were found to affect the spontaneous adsorption of BSM onto solid surfaces; BSM adsorbed more onto hydrophobic surfaces than hydrophilic ones, and adsorbed more at pH 3.8 than at pH 7.......4. Thus, the highest "dry" adsorbed mass was observed for hydrophobic surfaces in pH 3.8 solution. However, a highest "wet" adsorbed mass, i.e. which includes the solvent coupled to the film, was observed for hydrophobic surfaces at pH 7.4. The mechanical stability of the films was studied...

  11. [Stability in drinking and surface water of nine virus species from different genera (author's transl)].

    Science.gov (United States)

    Mahnel, H; Ottis, K; Herlyn, M

    1977-01-01

    The stability of nine viruses, Aujeszky, Sindbis, Vesicular Stomatitis, Newcastle Disease, Vaccinia, FMD, HCC, Reo and Teschen virus in drinking and surface water was investigated comparatively at temperatures of 9 and 15 degrees C as well as the influence of water factors like seasonal difference in temperature, pH value, hardness and sort of water. The results can be summarized as follows: 1. At temperatures of 9 to 15 degrees C the majority of the viruses remained stabil in natural water for an astonishing long time. 2. Starting with virus concentration of about 10(4) infectious units per ml Teschen, Vaccinia, Reo, HCC and ND virus could mostly be demonstrated in water longer than 200 days and FMD, Aujeszky, Vesicular Stomatitis and Sindbis virus for 20 to 50 days on average at 9 degrees C. The stability of the viruses investigated decreased in water in the named turn. 3. Based on these results it can be assumed that under natural conditions with very low virus content of some particles the labile viruses such as Toga, Herpes, Rhabdo and pH labile Picorna remain infectious in water for some days. They should not have any importance as water contaminants. More resistant viruses like Paramyxo may keep infectious for weeks and very stabile viruses such as Entero, Reo, Adeno and Pox viruses several weeks to months. 4. As to factors temperature, pH, hardness and sort of water-within the naturally differing range-only the temperature and only in the case of less resistant viruses showed significant influence on the virus stability in water.

  12. Surface Curvature-Induced Directional Movement of Water Droplets

    CERN Document Server

    Lv, Cunjing; Yin, Yajun; Zheng, Quanshui

    2010-01-01

    Here we report a surface curvature-induced directional movement phenomenon, based on molecular dynamics simulations, that a nanoscale water droplet at the outer surface of a graphene cone always spontaneously moves toward the larger end of the cone, and at the inner surface toward the smaller end. The analysis on the van der Waals interaction potential between a single water molecule and a curved graphene surface reveals that the curvature with its gradient does generate the driving force resulting in the above directional motion. Furthermore, we found that the direction of the above movement is independent of the wettability, namely is regardless of either hydrophobic or hydrophilic of the surface. However, the latter surface is in general leading to higher motion speed than the former. The above results provide a basis for a better understanding of many reported observations, and helping design of curved surfaces with desired directional surface water transportation.

  13. Concepts of fen and bog re-examined in relation to bryophyte cover and the acidity of surface waters

    Directory of Open Access Journals (Sweden)

    Eville Gorham

    2014-01-01

    Full Text Available Studies of surface-water pH and bryophyte assemblages in 440 plots from five peatland regions across northern North America reveal a very distinct, two-fold division into fens with a pH mode at 6.76-7.00, in which Amblystegiaceae are prominent, and bogs with a pH mode at 4.01-4.25, in which Sphagnaceae are dominant. The relevance of the data to past and current views on peatland classification is explored.

  14. Factors affecting pH change in alkaline waste water treatment - II: Carbon dioxide production

    NARCIS (Netherlands)

    Lijklema, L.

    1971-01-01

    The carbon dioxide produced during biological oxidation of wastewater has a pronounced influence upon the pH that is attained in the activated sludge process. The quantity produced is proportional to the COD removed, its degree of oxidation and depends also on the oxidation level of the substrate. A

  15. Sampling procedure for lake or stream surface water chemistry

    Science.gov (United States)

    Robert Musselman

    2012-01-01

    Surface waters collected in the field for chemical analyses are easily contaminated. This research note presents a step-by-step detailed description of how to avoid sample contamination when field collecting, processing, and transporting surface water samples for laboratory analysis.

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

    Science.gov (United States)

    Okome, Gloria Eloho

    2013-01-01

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

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

    Science.gov (United States)

    Okome, Gloria Eloho

    2013-01-01

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

  18. Adsorption behavior of methacryloyloxydecyl dihydrogen phosphate on an apatite surface at neutral pH.

    Science.gov (United States)

    Bista, Baba; Nakashima, Syozi; Nikaido, Toru; Sadr, Alireza; Takagaki, Tomohiro; Romero, Maria J R H; Sato, Takaaki; Tagami, Junji

    2016-04-01

    This study aimed to quantify the adsorption affinity of neutralized 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP-N) toward hydroxyapatite (HA) and dicalcium phosphate dihydrate (DCPD) at pH 7.0 by employing the Langmuir isotherm model. Furthermore, the effects of inorganic phosphate (Pi) and fluoride (F(-) ) ions on the adsorption of 10-MDP-N onto HA and DCPD were examined. Fixed amounts of HA and DCPD powders were suspended in different concentrations of 10-MDP-N solutions and were incubated for 18 h. Equilibrated concentrations of 10-MDP-N were measured by spectrophotometry and the adsorption affinity was estimated using the Langmuir model. Moreover, the adsorption was examined by zeta-potential analysis. The results indicated that significant Langmuir correlation was noted in both substrates, along with an increasing negative zeta-potential; however, in DCPD the correlation was less strong. The addition of 1.0 mM Pi slightly delayed the adsorption of 10-MDP-N onto both substrates, whereas 3.0 mM Pi drastically delayed adsorption onto HA but completely inhibited adsorption onto DCPD. Up to 50 ppm, F(-) enhanced the adsorption onto HA, and the adsorption plateaued at higher concentrations of F(-) , whereas no obvious influence of F(-) on the adsorption onto DCPD was noted.

  19. Surface ocean pH response to variations in pCO 2 through two full glacial cycles

    Science.gov (United States)

    Hönisch, Bärbel; Hemming, N. Gary

    2005-07-01

    Knowledge of past atmospheric pCO 2 is important for evaluating the role of greenhouse gases in climate forcing. Ice core records show the tight correlation between climate change and pCO 2, but records are limited to the past ˜900 kyr. We present surface ocean pH and PCO 2 data, reconstructed from boron isotopes in planktonic foraminifera over two full glacial cycles (0-140 and 300-420 kyr). The data co-vary strongly with the Vostok pCO 2-record and demonstrate that the coupling between surface ocean chemistry and the atmosphere is recorded in marine archives, allowing for quantitative estimation of atmospheric pCO 2 beyond the reach of ice cores.

  20. Spread mixed monolayers of deoxycholic and dehydrocholic acids at the air-water interface, effect of subphase pH. Characterization by axisymmetric drop shape analysis.

    Science.gov (United States)

    Messina, Paula V; Fernández-Leyes, Marcos D; Prieto, Gerardo; Ruso, Juan M; Sarmiento, Félix; Schulz, Pablo C

    2008-01-01

    Bile acids (deoxycholic and dehydrocholic acids) spread mixed monolayers behavior at the air/water interface were studied as a function of subphase pH using a constant surface pressure penetration Langmuir balance based on the Axisymmetric Drop Shape Analysis (ADSA). We examined the influence of electrostatic, hydrophobic and hydration forces on the interaction between amphiphilic molecules at the interface by the collapse area values, the thermodynamic parameters and equation of state virial coefficients analysis. The obtained results showed that at neutral (pH=6.7) or basic (pH=10) subphase conditions the collapse areas values are similar to that of cholanoic acid and consistent with the cross-sectional area of the steroid nucleus (approximately 40 A(2)). The Gibbs energy of mixing values (DeltaG(mix) or =1). Such behavior indicates that the polar groups of the molecules interacts each other more strongly by repulsive electrostatic forces than with the more hydrophobic part of the molecule.

  1. Shallow Water Propagation and Surface Reverberation Modeling

    Science.gov (United States)

    2014-07-29

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

  2. Quality of surface-water supplies in the Triangle Area of North Carolina, water years 2012–13

    Science.gov (United States)

    Pfeifle, C.A.; Cain, J.L.; Rasmussen, R.B.

    2016-09-07

    Surface-water supplies are important sources of drinking water for residents in the Triangle area of North Carolina, which is located within the upper Cape Fear and Neuse River Basins. Since 1988, the U.S. Geological Survey and a consortium of local governments have tracked water-quality conditions and trends in several of the area’s water-supply lakes and streams. This report summarizes data collected through this cooperative effort, known as the Triangle Area Water Supply Monitoring Project, during October 2011 through September 2012 (water year 2012) and October 2012 through September 2013 (water year 2013). Major findings for this period include:Annual precipitation was approximately 2 percent above the long-term mean (average) annual precipitation in 2012 and approximately 3 percent below the long-term mean in 2013.In water year 2012, streamflow was generally below the long-term mean during most of the period for the 10 project streamflow gaging stations. Streamflow was near or above the long-term mean at the same streamflow gaging stations during the 2013 water year.More than 7,000 individual measurements of water quality were made at a total of 17 sites—6 in the Neuse River Basin and 11 in the Cape Fear River Basin. Forty-three water-quality properties or constituents were measured; State water-quality standards exist for 23 of these.All observations met State water-quality standards for pH, temperature, hardness, chloride, fluoride, sulfate, nitrate, arsenic, cadmium, chromium, lead, nickel, and selenium.North Carolina water-quality standards were exceeded one or more times for dissolved oxygen, dissolved-oxygen percent saturation, turbidity, chlorophyll a, copper, iron, manganese, mercury, silver, and zinc. Exceedances occurred at all 17 sites.Stream samples collected during storm events contained elevated concentrations of 19 water-quality constituents relative to non-storm events.

  3. Dependence on surface pH and surface substrate concentration of activity of microsome-bound arylsulfatase C and the surface charge density in the vicinity of the enzyme.

    Science.gov (United States)

    Masamoto, K

    1984-03-01

    Dependence on the salt concentration of the activity of microsome-bound arylsulfatase C [EC 3.1.6.1] from rat liver was examined. The activity increased with increasing salt concentration in the reaction medium in the whole pH range tested. This effect can be explained by the dependence of the reaction rate on the surface pH and the surface concentration of the ionic substrate. The dependence on salt concentration of the activity of the microsome-bound arylsulfatase C and the pH-dependences of Vmax and Km of the enzyme were used for the estimation of pH at the microsomal surface. The two values of the surface pH (surface potential) and the salt concentration were applied to the Gouy-Chapman equation. The value of -0.39 +/- 0.08 X 10(-3) elementary charge/A2 was obtained as the surface charge density in the vicinity of the microsome-bound arylsulfatase C. This was smaller than the over-all value for microsomes (-1.08 +/- 0.04 X 10(-3) elementary charge/A2; Masamoto, K. (1982) J. Biochem. 92, 365-371). This suggests that the anion concentration in the vicinity of the enzyme on microsomes is lower than that in the bulk aqueous phase and is higher than the average value at the microsomal surface when the salt concentration is low.

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

    Science.gov (United States)

    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.

  5. Variation of Skin Surface pH, Sebum Content and Stratum Corneum Hydration with Age and Gender in a Large Chinese Population

    National Research Council Canada - National Science Library

    Man, M.Q; Xin, S.J; Song, S.P; Cho, S.Y; Zhang, X.J; Tu, C.X; Feingold, K.R; Elias, P.M

    2009-01-01

    .... The results to date of studies on skin surface pH, stratum corneum (SC) hydration and sebum content in both genders and at various ages have been inconclusive, which was in part due to small sample size...

  6. Efficacy of pH elevation as a bactericidal strategy for treating ballast water of freight carriers

    Directory of Open Access Journals (Sweden)

    Clifford E. Starliper

    2015-05-01

    Full Text Available Treatment of ship ballast water with sodium hydroxide (NaOH is one method currently being developed to minimize the risk to introduce aquatic invasive species. The bactericidal capability of sodium hydroxide was determined for 148 bacterial strains from ballast water collected in 2009 and 2010 from the M/V Indiana Harbor, a bulk-freight carrier plying the Laurentian Great Lakes, USA. Primary culture of bacteria was done using brain heart infusion agar and a developmental medium. Strains were characterized based on PCR amplification and sequencing of a portion of the 16S rRNA gene. Sequence similarities (99+ % were determined by comparison with the National Center for Biotechnology Information (NCBI GenBank catalog. Flavobacterium spp. were the most prevalent bacteria characterized in 2009, comprising 51.1% (24/47 of the total, and Pseudomonas spp. (62/101; 61.4% and Brevundimonas spp. (22/101; 21.8% were the predominate bacteria recovered in 2010; together, comprising 83.2% (84/101 of the total. Testing was done in tryptic soy broth (TSB medium adjusted with 5 N NaOH. Growth of each strain was evaluated at pH 10.0, pH 11.0 and pH 12.0, and 4 h up to 72 h. The median cell count at 0 h for 148 cultures was 5.20 × 106 cfu/mL with a range 1.02 × 105–1.60 × 108 cfu/mL. The TSB adjusted to pH 10.0 and incubation for less than 24 h was bactericidal to 52 (35.1% strains. Growth in pH 11.0 TSB for less than 4 h was bactericidal to 131 (88.5% strains and pH 11.0 within 12 h was bactericidal to 141 (95.3%. One strain, Bacillus horikoshii, survived the harshest treatment, pH 12.0 for 72 h.

  7. Characterization of Drain Surface Water: Environmental Profile, Degradation Level and Geo-statistic Monitoring

    Directory of Open Access Journals (Sweden)

    Muhammad Waseem Mumtaz

    2015-12-01

    Full Text Available The physico-chemical characterization of the surface water. Samples was carried out collected from nine sampling points of drain passing by the territory of Hafizabad city, Punjab, Pakistan. The water of drain is used by farmers for irrigation purposes in nearby agricultural fields. Twenty water quality parameters were evaluated in three turns and the results obtained were compared with the National Environmental Quality Standards (NEQS municipal and industrial effluents prescribed limits. The highly significant difference (p0.05 was noted for temperature, pH, electrical conductivity, hardness, calcium, sodium, chemical oxygen demand and chloride among water samples from different sampling points. Furthermore, the experimental results of different water quality parameters studied at nine sampling points of the drain were used and interpolated in ArcGIS 9.3 environment system using kriging techniques to obtain calculated values for the remaining locations of the Drain.

  8. Surface water quality assessment by environmetric methods.

    Science.gov (United States)

    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.

  9. 40 CFR 257.3-3 - Surface water.

    Science.gov (United States)

    2010-07-01

    ... 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 facility... Water Act, as amended. (b) For purposes of section 4004(a) of the Act, a facility shall not cause...

  10. Calcium carbonate saturation in the surface water of the Arctic Ocean: undersaturation in freshwater influenced shelves

    Directory of Open Access Journals (Sweden)

    M. Chierici

    2009-05-01

    Full Text Available In the summer of 2005, we sampled surface water and measured pH and total alkalinity (AT underway aboard IB Oden along the Northwest Passage from Cape Farwell (South Greenland to the Chukchi Sea. We investigated variability of carbonate system parameters, focusing particularly on carbonate concentration [CO32−] and calcium carbonate saturation states, as related to freshwater addition, biological processes and physical upwelling. Measurements on AT, pH at 15°C, salinity (S and sea surface temperature (SST, were used to calculate total dissolved inorganic carbon (DIC, [CO32−] and saturation of aragonite (ΩAr and calcite (ΩCa in the surface water. The same parameters were measured in the water column of the Bering Strait. Some surface waters in the Canadian Arctic Archipelago (CAA and on the Mackenzie shelf (MS were found to be undersaturated with respect to aragonite (ΩAr<1. In these areas, surface water was low in AT and DIC (<1500 μmol kg−1 relative to seawater and showed low [CO32−]. The low saturation states were probably due to the effect of dilution due from freshwater addition by sea ice melt (CAA and river runoff (MS. High AT and DIC and low pH, corresponded with the lowest [CO32−], ΩAr and ΩCa, observed near Cape Bathurst and along the South Chukchi Peninsula. This was linked to physical upwelling of subsurface water with elevated CO2. Highest surface ΩAr and ΩCa of 3.0 and 4.5, respectively, were found on the Chukchi Sea shelf and in the cold water north of Wrangel Island, which is heavily influenced by high CO2 drawdown and lower DIC from intense biological production. In the western Bering Strait, the cold and saline Anadyr Current carries water that is enriched in AT and DIC from enhanced organic matter remineralization, resulting in

  11. Calcium carbonate saturation in the surface water of the Arctic Ocean: undersaturation in freshwater influenced shelves

    Directory of Open Access Journals (Sweden)

    A. Fransson

    2009-11-01

    Full Text Available In the summer of 2005, we sampled surface water and measured pH and total alkalinity (AT underway aboard IB Oden along the Northwest Passage from Cape Farewell (South Greenland to the Chukchi Sea. We investigated the variability of carbonate system parameters, focusing particularly on carbonate concentration [CO32−] and calcium carbonate saturation states, as related to freshwater addition, biological processes and physical upwelling. Measurements on AT, pH at 15°C, salinity (S and sea surface temperature (SST, were used to calculate total dissolved inorganic carbon (CT, [CO32−] and the saturation of aragonite (ΩAr and calcite (ΩCa in the surface water. The same parameters were measured in the water column of the Bering Strait. Some surface waters in the Canadian Arctic Archipelago (CAA and on the Mackenzie shelf (MS were found to be undersaturated with respect to aragonite (ΩAr<1. In these areas, surface water was low in AT and CT (<1500 μmol kg−1 relative to seawater and showed low [CO32−]. The low saturation states were probably due to the likely the effect of dilution due to freshwater addition by sea ice melt (CAA and river runoff (MS. High AT and CT and low pH, corresponded with the lowest [CO32−], ΩAr and ΩCa, observed near Cape Bathurst and along the South Chukchi Peninsula. This was linked to the physical upwelling of subsurface water with elevated CO2. The highest surface ΩAr and ΩCa of 3.0 and 4.5, respectively, were found on the Chukchi Sea shelf and in the cold water north of Wrangel Island, which is heavily influenced by high CO2 drawdown and lower CT from intense biological production. In the western Bering Strait, the cold and saline Anadyr Current carries water that is enriched in AT and

  12. Preliminary monitoring of faecal indicator organisms of surface water ...

    African Journals Online (AJOL)

    Preliminary monitoring of faecal indicator organisms of surface water: A case study ... in Mvudi River used as a source of domestic water for people who live around it. ... of Water Affairs and Forestry of South Africa (DWAF) and the World Health ...

  13. Layers of Porous Superhydrophobic Surfaces for Robust Water Repellency

    Science.gov (United States)

    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.

  14. Optimal Soil Eh, pH, and Water Management for Simultaneously Minimizing Arsenic and Cadmium Concentrations in Rice Grains.

    Science.gov (United States)

    Honma, Toshimitsu; Ohba, Hirotomo; Kaneko-Kadokura, Ayako; Makino, Tomoyuki; Nakamura, Ken; Katou, Hidetaka

    2016-04-19

    Arsenic (As) and cadmium (Cd) concentrations in rice grains are a human health concern. We conducted field experiments to investigate optimal conditions of Eh and pH in soil for simultaneously decreasing As and Cd accumulation in rice. Water managements in the experiments, which included continuous flooding and intermittent irrigation with different intervals after midseason drainage, exerted striking effects on the dissolved As and Cd concentrations in soil through changes in Eh, pH, and dissolved Fe(II) concentrations in the soil. Intermittent irrigation with three-day flooding and five-day drainage was found to be effective for simultaneously decreasing the accumulation of As and Cd in grain. The grain As and Cd concentrations were, respectively, linearly related to the average dissolved As and Cd concentrations during the 3 weeks after heading. We propose a new indicator for expressing the degree to which a decrease in the dissolved As or Cd concentration is compromised by the increase in the other. For minimizing the trade-off relationship between As and Cd in rice grains in the field investigated, water management strategies should target the realization of optimal soil Eh of -73 mV and pH of 6.2 during the 3 weeks after heading.

  15. Multivariate statistical analysis of water chemistry conditions in three wastewater stabilization ponds with algae blooms and pH fluctuations.

    Science.gov (United States)

    Wallace, Jack; Champagne, Pascale; Hall, Geof

    2016-06-01

    The wastewater stabilization ponds (WSPs) at a wastewater treatment facility in eastern Ontario, Canada, have experienced excessive algae growth and high pH levels in the summer months. A full range of parameters were sampled from the system and the chemical dynamics in the three WSPs were assessed through multivariate statistical analysis. The study presents a novel approach for exploratory analysis of a comprehensive water chemistry dataset, incorporating principal components analysis (PCA) and principal components (PC) and partial least squares (PLS) regressions. The analyses showed strong correlations between chl-a and sunlight, temperature, organic matter, and nutrients, and weak and negative correlations between chl-a and pH and chl-a and DO. PCA reduced the data from 19 to 8 variables, with a good fit to the original data matrix (similarity measure of 0.73). Multivariate regressions to model system pH in terms of these key parameters were performed on the reduced variable set and the PCs generated, for which strong fits (R(2) > 0.79 with all data) were observed. The methodologies presented in this study are applicable to a wide range of natural and engineered systems where a large number of water chemistry parameters are monitored resulting in the generation of large data sets. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Non-monotonic swelling of surface grafted hydrogels induced by pH and/or salt concentration

    Energy Technology Data Exchange (ETDEWEB)

    Longo, Gabriel S. [Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), CONICET, La Plata (Argentina); Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60208 (United States); Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois 60208 (United States); Olvera de la Cruz, Monica [Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois 60208 (United States); Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208 (United States); Department of Chemistry, Northwestern University, Evanston, Illinois 60208 (United States); Szleifer, I., E-mail: igal@northwestern.edu [Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60208 (United States); Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois 60208 (United States); Department of Chemistry, Northwestern University, Evanston, Illinois 60208 (United States)

    2014-09-28

    We use a molecular theory to study the thermodynamics of a weak-polyacid hydrogel film that is chemically grafted to a solid surface. We investigate the response of the material to changes in the pH and salt concentration of the buffer solution. Our results show that the pH-triggered swelling of the hydrogel film has a non-monotonic dependence on the acidity of the bath solution. At most salt concentrations, the thickness of the hydrogel film presents a maximum when the pH of the solution is increased from acidic values. The quantitative details of such swelling behavior, which is not observed when the film is physically deposited on the surface, depend on the molecular architecture of the polymer network. This swelling-deswelling transition is the consequence of the complex interplay between the chemical free energy (acid-base equilibrium), the electrostatic repulsions between charged monomers, which are both modulated by the absorption of ions, and the ability of the polymer network to regulate charge and control its volume (molecular organization). In the absence of such competition, for example, for high salt concentrations, the film swells monotonically with increasing pH. A deswelling-swelling transition is similarly predicted as a function of the salt concentration at intermediate pH values. This reentrant behavior, which is due to the coupling between charge regulation and the two opposing effects triggered by salt concentration (screening electrostatic interactions and charging/discharging the acid groups), is similar to that found in end-grafted weak polyelectrolyte layers. Understanding how to control the response of the material to different stimuli, in terms of its molecular structure and local chemical composition, can help the targeted design of applications with extended functionality. We describe the response of the material to an applied pressure and an electric potential. We present profiles that outline the local chemical composition of the

  17. Conductimetric study of struvite crystallization in water as a function of pH

    Science.gov (United States)

    Moulessehoul, A.; Gallart-Mateu, D.; Harrache, D.; Djaroud, S.; de la Guardia, M.; Kameche, M.

    2017-08-01

    The main objective of this work was to investigate the best pH for phosphorus removal from synthetic aqueous solutions using chemical precipitation of struvite, at constant temperature. The experimental approach, developed in the present study, consisted to precipitate struvite in synthetic wastewater containing PO43-, NH4+ and Mg2+ ions in an equal molar ratio, using a stirred tank with continuous monitoring by conductimetry, at 25 °C. Different laboratory experiments were used to evaluate the effects of pH in the range of 8.5 till 11.8, on size, shape, and purity of the precipitated crystals. Struvite crystals were characterized by Infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The phosphorus conversion rate was determined by spectrophotometric determination of residual phosphorus. The experimental results showed that pH 8.5 provided the best conditions for struvite crystal growth, being obtained a 98% phosphorus to phosphate conversion rate, for an initial concentration of 474 mg/L.

  18. Conventional Treatment of Surface Water Using Moringa Oleifera Seeds Extract as a Primary Coagulant

    Directory of Open Access Journals (Sweden)

    Suleyman A. Muyibi, Ahmed Hissein M Birima, Thamer A. Mohammed

    2012-10-01

    Full Text Available The present study involved the use of a model pilot scale water treatment plant to treat turbid surface water from a stream using processed Moringa oleifera seed with 25 % w/w oil extracted as primary coagulant. The water treatment plant was made up of four unit operations: coagulation, flocculation, sedimentation, and filtration (rapid sand filter. Test runs were carried out for three hours per run over a three-month period with turbidities ranging from 18 to 261 NTU. The turbidity, pH, and alkalinity as well as the filter head loss were measured every 30 minutes during the experimental runs. Average turbidity removal of up to 96 % at an effective doses of 20 and 30 mg/l of oil extracted M. oleifera for low (< 50 NTU and moderate turbidity (< 100 NTU water respectively was observed doses 50 – 80 mg/l for high turbidity (> 100 NTU water. M. oleifera seed extract was found to have no significant effect on pH or alkalinity of the water. The residual turbidities measured during most of the test runs satisfied the Malaysian Guideline for Drinking Water Supplies. Key Words: Moringa oleifera, primary coagulant, coagulation, pilot plant, filtration.

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

    Science.gov (United States)

    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.

  20. OCCURRENCE OF ENTERIC VIRUSES IN SURFACE WATERS

    Science.gov (United States)

    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...

  1. Interim Enhanced Surface Water Treatment Rule Documents

    Science.gov (United States)

    The IESWTR balances the need for treatment with potential increases in disinfection by -products. The materials found on this page are intended to assist public water systems and state in the implementation of the IESWTR.

  2. SurfaceWater Source Protection Areas (SPAs)

    Data.gov (United States)

    Vermont Center for Geographic Information — Source Protection Area (SPA) boundaries have been located on RF 24000 & RF 25000 scale USGS topographic maps by Water Supply Division (DEC) and VT Dept of Health...

  3. SURFACE WATER QUALITY IN ADDIS ABABA, ETHIOPIA

    African Journals Online (AJOL)

    environmental pollution derived from domestic and industrial activities. Due to the inadequacy of controlled waste management strategies and waste treatment plants ... Oxygen Demand (COD), Biological Oxygen Demand (BOD) and Dissolved ... appropriate waste water purifying plants. ..... University of Turku, Finland. 2.

  4. Bioinspired aquatic microrobot capable of walking on water surface like a water strider.

    Science.gov (United States)

    Zhang, Xinbin; Zhao, Jie; Zhu, Qing; Chen, Ning; Zhang, Mingwen; Pan, Qinmin

    2011-07-01

    Walking on the water surface is a dream of humans, but it is exactly the way of life for some aquatic insects. In this study, a bionic aquatic microrobot capable of walking on the water surface like a water strider was reported. The novel water strider-like robot consisted of ten superhydrophobic supporting legs, two miniature dc motors, and two actuating legs. The microrobot could not only stand effortlessly but also walk and turn freely on the water surface, exhibiting an interesting motion characteristic. A numerical model describing the interface between the partially submerged leg and the air-water surface was established to fully understand the mechanism for the large supporting force of the leg. It was revealed that the radius and water contact angle of the legs significantly affect the supporting force. Because of its high speed, agility, low cost, and easy fabrication, this microrobot might have a potential application in water quality surveillance, water pollution monitoring, and so on.

  5. Summit crater lake observations, and the location, chemistry, and pH of water samples near Mount Chiginagak volcano, Alaska: 2004-2012

    Science.gov (United States)

    Schaefer, Janet R.; Scott, William E.; Evans, William C.; Wang, Bronwen; McGimsey, Robert G.

    2013-01-01

    maximum depth of 45 m (resulting pH ~2.9), and preventing the annual salmon run in the King Salmon River. A simultaneous release of gas and acidic aerosols from the crater caused widespread vegetation damage along the flow path. Since 2005, we have been monitoring the crater lake water that continues to flow into Mother Goose Lake by collecting surface water samples for major cation and anion analysis, measuring surface-water pH of affected drainages, and photo-documenting the condition of the summit crater lake. This report describes water sampling locations, provides a table of chemistry and pH measurements, and documents the condition of the summit crater between 2004 and 2011. In September 2013, the report was updated with results of water-chemistry samples collected in 2011 and 2012, which were added as an addendum.

  6. A Study on the Dissolution Kinetics of Basalt—Water Interaction under Different pH Conditions I:Release of Elements and pH Neutralization Effect

    Institute of Scientific and Technical Information of China (English)

    党志; 侯英

    1993-01-01

    Experimental research on the chemical weathering of alkaline-olivine basalt from Huangyi Mountain,Kuandain County,Liaoning.Province and olivine basalt from Dayangke,Mingxi County,Fujian Province has shown that the acidity of the solution tends to become neutral regardless of what the acidity of the starting solution would be during basalt0-water interaction.We call this phenome-non“pH neutralized Effect”.The dissolved species in the solution were determined and unreacted and reacted sample-surface chemical components involved or uninvolved in reaction were analyzed using X-ray photoelectron spectroscopy(XPS).The results revealed two different mechanisms of dissolution of basalt in acidic and basic solutions.

  7. Unique water-water coordination tailored by a metal surface

    DEFF Research Database (Denmark)

    Schiros, T.; Andersson, Klas Jerker; MacNaughton, J.;

    2013-01-01

    At low coverage of water on Cu(110), substrate-mediated electrostatics lead to zigzagging chains along [001] as observed with STM [T. Yamada, S. Tamamori, H. Okuyama, and T. Aruga, “Anisotropic water chain growth on Cu(110) observed with scanning tunneling microscopy” Phys. Rev. Lett. 96, 036105...... (2006)]. Using x-ray absorption spectroscopy we find an anomalous low-energy resonance at ~533.1 eV which, based on density functional theory spectrum simulations, we assign to an unexpected configuration of water units whose uncoordinated O-H bonds directly face those of their neighbors...

  8. Characterization of an organic acid analog model in Adirondack, New York, surface waters

    Science.gov (United States)

    Fakhraei, H.; Driscoll, C. T.

    2013-12-01

    Natural waters include a variety of organic matter that differs in composition and functional groups. Dissolved organic matter is important but difficult to characterize acidic and metal binding (e.g., Al) functional groups in chemical equilibrium models. In this study data from Adirondack Lake Survey were used to calibrate an organic acid analog model in order to quantify the influence of organic acids on surface water chemistry. The study sites in the Adirondack region of New York have diverse levels of dissolved organic carbon (DOC), used as a surrogate for organic acids. DOC in 55 Adirondack surface waters varies from 180 μmol C/l (in Little Echo Pond) to 1263 μmol C/l (in Sunday Pond). To reduce the variability inherited in the large raw data set, suite of mean observations was constructed by grouping and averaging measured data into pH intervals of 0.05 pH units from pH 4.15 to 7.3. A chemical equilibrium model, which includes major solutes in natural waters, was linked to an optimization algorithm (genetic algorithm) to calibrate a triprotic organic analog model which includes proton and aluminum binding by adjusting the dissociation constants and site density of DOC. The object of fitting procedure was to simultaneously minimize the discrepancy between observed and simulated pH, acid neutralizing capacity (ANC), organic monomeric aluminum and inorganic monomeric aluminum. A sensitivity analysis on calibrated values indicate that the speciation of the modeled solutes are most responsive to the dissociation constant of AlOrg= Al3+ + Org3- reaction (Org3- represents organic anion), the site density of DOC and the second H+ dissociation constant of the triprotic organic analog (i.e. H2Org- = 2H+ + Org3- reaction).

  9. Modelling biofilm formation of Salmonella enterica ser. Newport as a function of pH and water activity.

    Science.gov (United States)

    Dimakopoulou-Papazoglou, Dafni; Lianou, Alexandra; Koutsoumanis, Konstantinos P

    2016-02-01

    The effect of pH and water activity (aw) on the formation of biofilm by Salmonella enterica ser. Newport, previously identified as a strong biofilm producer, was assessed. Biofilm formation was evaluated in tryptone soy broth at 37 °C and at different combinations of pH (3.3-7.8) and aw (0.894-0.997). In total, 540 biofilm formation tests in 108 pH and aw combinations were carried out in polystyrene microtiter plates using crystal violet staining and optical density (OD; 580 nm) measurements. Since the individual effects of pH and aw on biofilm formation had a similar pattern to that observed for microbial growth rate, cardinal parameter models (CPMs) were used to describe these effects. CPMs described successfully the effects of these two environmental parameters, with the estimated cardinal values of pHmin, pHopt, pHmax, awmin and awopt being 3.58, 6.02, 9.71, 0.894 and 0.994, respectively. The CPMs assumption of the multiplicative inhibitory effect of environmental factors was validated in the case of biofilm formation using additional independent data (i.e. 430 OD data at 86 different combinations of pH and aw). The validation results showed a good agreement (r(2) = 0.938) between observed and predicted OD with no systematic error. In the second part of this study, a probabilistic model predicting the pathogen's biofilm formation boundaries was developed, and the degree of agreement between predicted probabilities and observations was as high as 99.8%. Hence, the effect of environmental parameters on biofilm formation can be quantitatively expressed using mathematical models, with the latter models, in turn, providing useful information for biofilm control in food industry environments.

  10. All-Atom Continuous Constant pH Molecular Dynamics With Particle Mesh Ewald and Titratable Water.

    Science.gov (United States)

    Huang, Yandong; Chen, Wei; Wallace, Jason A; Shen, Jana

    2016-11-08

    Development of a pH stat to properly control solution pH in biomolecular simulations has been a long-standing goal in the community. Toward this goal recent years have witnessed the emergence of the so-called constant pH molecular dynamics methods. However, the accuracy and generality of these methods have been hampered by the use of implicit-solvent models or truncation-based electrostatic schemes. Here we report the implementation of the particle mesh Ewald (PME) scheme into the all-atom continuous constant pH molecular dynamics (CpHMD) method, enabling CpHMD to be performed with a standard MD engine at a fractional added computational cost. We demonstrate the performance using pH replica-exchange CpHMD simulations with titratable water for a stringent test set of proteins, HP36, BBL, HEWL, and SNase. With the sampling time of 10 ns per replica, most pKa's are converged, yielding the average absolute and root-mean-square deviations of 0.61 and 0.77, respectively, from experiment. Linear regression of the calculated vs experimental pKa shifts gives a correlation coefficient of 0.79, a slope of 1, and an intercept near 0. Analysis reveals inadequate sampling of structure relaxation accompanying a protonation-state switch as a major source of the remaining errors, which are reduced as simulation prolongs. These data suggest PME-based CpHMD can be used as a general tool for pH-controlled simulations of macromolecular systems in various environments, enabling atomic insights into pH-dependent phenomena involving not only soluble proteins but also transmembrane proteins, nucleic acids, surfactants, and polysaccharides.

  11. Degradation of Kresoxim-Methyl in Water: Impact of Varying pH, Temperature, Light and Atmospheric CO2 Level.

    Science.gov (United States)

    Khandelwal, Ashish; Gupta, Suman; Gajbhiye, Vijay T; Varghese, Eldho

    2016-01-01

    In the present investigation, persistence of kresoxim-methyl (a broad spectrum strobilurin fungicide) was studied in water. Results revealed that kresoxim-methyl readily form acid metabolite. Therefore, residues of kresoxim-methyl were quantified on the basis of parent molecule alone and sum total of kresoxim-methyl and its acid metabolite. In water, influence of various abiotic factors like pH, temperature, light and atmospheric carbon dioxide level on dissipation of kresoxim-methyl was studied. The half life value for kresoxim-methyl and total residue varied from 1 to 26.1 and 6.1 to 94.0 days under different conditions. Statistical analysis revealed the significant effect of abiotic factors on the dissipation of kresoxim-methyl from water.

  12. Evaluating the generation efficiency of hydrogen peroxide in water by pulsed discharge over water surface and underwater bubbling pulsed discharge

    Science.gov (United States)

    Shang, Kefeng; Li, Jie; Wang, Xiaojing; Yao, Dan; Lu, Na; Jiang, Nan; Wu, Yan

    2016-01-01

    Pulsed electric discharge over water surface/in water has been used to generate reactive species for decomposing the organic compounds in water, and hydrogen peroxide (H2O2) is one of the strong reactive species which can be decomposed into another stronger oxidative species, hydroxyl radical. The production efficacy of H2O2 by a gas phase pulsed discharge over water surface and an underwater bubbling pulsed discharge was evaluated through diagnosis of H2O2 by a chemical probe method. The experimental results show that the yield and the production rate of H2O2 increased with the input energy regardless of the electric discharge patterns, and the underwater bubbling pulsed discharge was more advantageous for H2O2 production considering both the yield and the production rate of H2O2. Results also indicate that the electric discharge patterns also influenced the water solution properties including the conductivity, the pH value and the water temperature.

  13. Measurements of water surface snow lines in classical protoplanetary disks

    CERN Document Server

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

    2015-01-01

    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 0.1-100 AU using two-dimensional dust and line radiative transfer modeling. The surface water distribution is modeled with a step model comprising 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 $\\sim 3-11$ 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 abu...

  14. Interactive effects of temperature, pH, and water activity on the growth kinetics of Shiga toxin-producing Escherichia coli O104:H4 3.

    Science.gov (United States)

    Juneja, Vijay K; Mukhopadhyay, Sudarsan; Ukuku, Dike; Hwang, Cheng-An; Wu, Vivian C H; Thippareddi, Harshavardhan

    2014-05-01

    The risk of non-O157 Shiga toxin-producing Escherichia coli strains has become a growing public health concern. Several studies characterized the behavior of E. coli O157:H7; however, no reports on the influence of multiple factors on E. coli O104:H4 are available. This study examined the effects and interactions of temperature (7 to 46°C), pH (4.5 to 8.5), and water activity (aw ; 0.95 to 0.99) on the growth kinetics of E. coli O104:H4 and developed predictive models to estimate its growth potential in foods. Growth kinetics studies for each of the 23 variable combinations from a central composite design were performed. Growth data were used to obtain the lag phase duration (LPD), exponential growth rate, generation time, and maximum population density (MPD). These growth parameters as a function of temperature, pH, and aw as controlling factors were analyzed to generate second-order response surface models. The results indicate that the observed MPD was dependent on the pH, aw, and temperature of the growth medium. Increasing temperature resulted in a concomitant decrease in LPD. Regression analysis suggests that temperature, pH, and aw significantly affect the LPD, exponential growth rate, generation time, and MPD of E. coli O104:H4. A comparison between the observed values and those of E. coli O157:H7 predictions obtained by using the U. S. Department of Agriculture Pathogen Modeling Program indicated that E. coli O104:H4 grows faster than E. coli O157:H7. The developed models were validated with alfalfa and broccoli sprouts. These models will provide risk assessors and food safety managers a rapid means of estimating the likelihood that the pathogen, if present, would grow in response to the interaction of the three variables assessed.

  15. Survival of Phytophthora infestans in Surface Water.

    Science.gov (United States)

    Porter, Lyndon D; Johnson, Dennis A

    2004-04-01

    ABSTRACT Coverless petri dishes with water suspensions of sporangia and zoospores of Phytophthora infestans were embedded in sandy soil in eastern Washington in July and October 2001 and July 2002 to quantify longevity of spores in water under natural conditions. Effects of solar radiation intensity, presence of soil in petri dishes (15 g per dish), and a 2-h chill period on survival of isolates of clonal lineages US-8 and US-11 were investigated. Spores in water suspensions survived 0 to 16 days under nonshaded conditions and 2 to 20 days under shaded conditions. Mean spore survival significantly increased from 1.7 to 5.8 days when soil was added to the water. Maximum survival time of spores in water without soil exposed to direct sunlight was 2 to 3 days in July and 6 to 8 days in October. Mean duration of survival did not differ significantly between chilled and nonchilled sporangia, but significantly fewer chilled spores survived for extended periods than that of nonchilled spores. Spores of US-11 and US-8 isolates did not differ in mean duration of survival, but significantly greater numbers of sporangia of US-8 survived than did sporangia of US-11 in one of three trials.

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

    Science.gov (United States)

    ,

    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.

  17. Assessment of Boron Doped Diamond Electrode Quality and Application to In Situ Modification of Local pH by Water Electrolysis.

    Science.gov (United States)

    Read, Tania L; Macpherson, Julie V

    2016-01-06

    Boron doped diamond (BDD) electrodes have shown considerable promise as an electrode material where many of their reported properties such as extended solvent window, low background currents, corrosion resistance, etc., arise from the catalytically inert nature of the surface. However, if during the growth process, non-diamond-carbon (NDC) becomes incorporated into the electrode matrix, the electrochemical properties will change as the surface becomes more catalytically active. As such it is important that the electrochemist is aware of the quality and resulting key electrochemical properties of the BDD electrode prior to use. This paper describes a series of characterization steps, including Raman microscopy, capacitance, solvent window and redox electrochemistry, to ascertain whether the BDD electrode contains negligible NDC i.e. negligible sp(2) carbon. One application is highlighted which takes advantage of the catalytically inert and corrosion resistant nature of an NDC-free surface i.e. stable and quantifiable local proton and hydroxide production due to water electrolysis at a BDD electrode. An approach to measuring the local pH change induced by water electrolysis using iridium oxide coated BDD electrodes is also described in detail.

  18. Surface complexation at calcium mineral-water interfaces

    OpenAIRE

    Wu, Liuming

    1994-01-01

    Surface reactions occurring at solid-water interfaces in calcium mineral-ligands systems have been studied. Both hydrous apatite and fluorite surfaces show clear amphoteric properties. An ion exchange process between lattice ions of F- on fluorite and OH- ions in bulk solution is discovered. The surface adsorption of Alizarin Red S and sodium oleate are determined. Surface chemical reaction models are established based on acidbase potentiometric titrations, solubility, adsorption and zeta-pot...

  19. A molecular dynamics study on surface properties of supercooled water

    Institute of Scientific and Technical Information of China (English)

    L(U) Yongjun; WEI Bingbo

    2006-01-01

    Molecular dynamics simulations were performed to study the surface properties of water in a temperature range from 228 to 293 K by using the extended simple point charge (SPC/E) and four-site TIP4P potentials. The calculated surface tension increases with the decrease of temperature, and moreover the slopes of the surface tension-temperature curves show a weak rise below 273 K, whereas no obvious anomalies appear near 228 K, which accords with the previous experiments. Compared with the measured values, the SPC/E potential shows a good agreement, and the TIP4P potential scription of the surface structure of supercooled water for the SPC/E. When simulating the orientational distributions of water molecules near the surface, the SPC/E potential produces higher ordering and larger surface potentials than the TIP4P potential.

  20. Tractor beam on the water surface

    CERN Document Server

    Punzmann, Horst; Xia, Hua; Falkovich, Gregory; Shats, Michael

    2014-01-01

    Can one send a wave to bring an object from a distance? The general idea is inspired by the recent success in moving micro particles using light and the development of a tractor beam concept. For fluid surfaces, however, the only known paradigm is the Stokes drift model, where linear planar waves push particles in the direction of the wave propagation. Here we show how to fetch a macroscopic floater from a large distance by sending a surface wave towards it. We develop a new method of remote manipulation of floaters by forming inward and outward surface jets, stationary vortices, and other complex surface flows using nonlinear waves generated by a vertically oscillating plunger. The flows can be engineered by changing the geometry and the power of a wave maker, and the flow dissipation. The new method is robust and works both for long gravity and for short capillary waves. We use a novel method of visualising 3D particle trajectories on the surface. This letter introduces a new conceptual framework for unders...

  1. Experimental Observation of Dark Solitons on Water Surface

    Science.gov (United States)

    2016-06-13

    vertical walls are made of transparent sections of glass supported by the metal frame. The water level of the free surface is measured with seven resistive...Experimental observation of dark solitons on water surface A. Chabchoub1,∗, O. Kimmoun2, H. Branger3, N. Hoffmann1, D. Proment4, M. Onorato4,5, and N...observation of dark solitons on the water surface. It takes the form of an amplitude drop of the carrier wave which does not change shape in propagation

  2. Survival of the faucet snail after chemical disinfection, pH extremes, and heated water bath treatments

    Science.gov (United States)

    Mitchell, A.J.; Cole, R.A.

    2008-01-01

    The faucet snail Bithynia tentaculata, a nonindigenous aquatic snail from Eurasia, was introduced into Lake Michigan in 1871 and has spread to the mid-Atlantic states, the Great Lakes region, Montana, and most recently, the Mississippi River. The faucet snail serves as intermediate host for several trematodes that have caused large-scale mortality among water birds, primarily in the Great Lakes region and Montana. It is important to limit the spread of the faucet snail; small fisheries equipment can serve as a method of snail distribution. Treatments with chemical disinfection, pH extremes, and heated water baths were tested to determine their effectiveness as a disinfectant for small fisheries equipment. Two treatments eliminated all test snails: (1) a 24-h exposure to Hydrothol 191 at a concentration of at least 20 mg/L and (2) a treatment with 50??C heated water for 1 min or longer. Faucet snails were highly resistant to ethanol, NaCl, formalin, Lysol, potassium permanganate, copper sulfate, Baquacil, Virkon, household bleach, and pH extremes (as low as 1 and as high as 13).

  3. Modified atmosphere packaging for prevention of mold spoilage of bakery products with different pH and water activity levels.

    Science.gov (United States)

    Guynot, M E; Marín, S; Sanchis, V; Ramos, A J

    2003-10-01

    A sponge cake analog was used to study the influence of pH, water activity (aw), and carbon dioxide (CO2) levels on the growth of seven fungal species commonly causing bakery product spoilage (Eurotium amstelodami, Eurotium herbariorum, Eurotium repens, Eurotium rubrum, Aspergillus niger, Aspergillus flavus, and Penicillium corylophilum). A full factorial design was used. Water activity, CO2, and their interaction were the main factors significantly affecting fungal growth. Water activity at levels of 0.80 to 0.90 had a significant influence on fungal growth and determined the concentration of CO2 needed to prevent cake analog spoilage. At an aw level of 0.85, lag phases increased twofold when the level of CO2 in the headspace increased from 0 to 70%. In general, no fungal growth was observed for up to 28 days of incubation at 25 degrees C when samples were packaged with 100% CO2, regardless of the aw level. Partial least squares projection to latent structures regression was used to build a polynomial model to predict sponge cake shelf life on the basis of the lag phases of all seven species tested. The model developed explained quite well (R2 = 79%) the growth of almost all species, which responded similarly to changes in tested factors. The results of this study emphasize the importance of combining several hurdles, such as modified atmosphere packaging, aw, and pH, that have synergistic or additive effects on the inhibition of mold growth.

  4. Drainage-water travel times as a key factor for surface water contamination

    OpenAIRE

    Groenendijk, P.; Eertwegh, van den, A.J.M.

    2004-01-01

    The importance of the unsaturated zone as an inextricable part of the hydrologic cycle has long been recognized. The root zone and the unsaturated sub-surface domain are chemically and biologically the most active zones. The interrelationships between soil, subsoil and surface waters make it unrealistic to treat the saturated and unsaturated zones and the discharge to surface waters separately. Point models describe vertical water flow in the saturated zone and possibly lateral flow by defini...

  5. Phosphate adsorption onto hematite: an in situ ATR-FTIR investigation of the effects of pH and loading level on the mode of phosphate surface complexation.

    Science.gov (United States)

    Elzinga, Evert J; Sparks, Donald L

    2007-04-01

    Phosphate adsorption on hematite was characterized as a function of pH (3.5-8.9) and phosphate concentration (5-500 microM) by in situ ATR-FTIR spectroscopy. Under most conditions a mixture of different (inner-sphere) phosphate complexes existed at the hematite surface, with the relative importance of these complexes varying with pH and surface coverage. Experiments using D(2)O and H(2)O indicated the presence of two protonated phosphate surface complexes at pH/pD=3.5-7.0. Comparison to spectra of protonated aqueous phosphate species suggested that these surface complexes are monoprotonated. The difference in the IR spectra of these complexes is tentatively interpreted to result from a different surface coordination, with one surface complex coordinated in a monodentate binuclear (bridging) fashion, and the second as a monodentate mononuclear complex. Alternatively, the bridging complex may be a (protonated) monodentate mononuclear complex exhibiting strong hydrogen bonding to an adjacent surface site, and the second species a monodentate complex exhibiting limited hydrogen bonding. Formation of the bridging complex is favored at lower pH values and higher surface loadings in the 3.5-7.0 pH range. At the highest pH values studied (8.5-9.0) a third complex, interpreted to be a nonprotonated monodentate mononuclear complex, is present along with the monodentate monoprotonated surface species. The importance of the nonprotonated monodentate complex increases with increasing surface coverage at these high pH values.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  8. Direct determination of thickness of sea surface microlayer using a pH microelectrode at original location

    Institute of Scientific and Technical Information of China (English)

    张正斌; 蔡卫君; 刘莲生; 刘春颖; 陈飞舟

    2003-01-01

    By using a pH microelectrode and ultramicro-vernier shift equipment,a new method to determine directly the thickness of the sea surface microlayer (SML) at original location, is advanced and founded, which is an important innovation on the SML sampling method and the SML research. Applying the intersecting straight line method, the SML thickness was found to be approximately 60 μm. This result is consistent not only with the measurement result, (50±10) μm, obtained with the conventional glass plate method, but also with the sudden change layer of physical and chemical properties of seawater, and with the results reported in the literature. The determination method will have the ocean biogeochemistry significance on marine chemistry.

  9. Electron bombardment of water adsorbed on Zr(0001) surfaces

    CERN Document Server

    Ankrah, S; Ramsier, R D

    2003-01-01

    A study of the effects of electron bombardment on water adsorbed on Zr(0001) is reported. Zirconium surfaces are dosed with isotopic water mixtures at 160 K followed by electron bombardment (485 eV). The system is then probed by low energy electron diffraction, temperature programmed desorption (TPD) and Auger electron spectroscopy (AES). No evidence is found that would indicate preferential mixing of hydrogen from the bulk with isotopic water dissociation products during TPD. However, electron bombardment results in the sharpening of a hydrogen/deuterium desorption peak near 320 K and the production of water near 730 K at low water exposures. In addition, although water does not oxidize Zr(0001) thermally, electron bombardment of adsorbed water induces a shift of about 2 eV in the Zr AES features indicating that the surface is partially oxidized by electron bombardment.

  10. A pinch of salt is all it takes: chemistry at the frozen water surface.

    Science.gov (United States)

    Kahan, Tara F; Wren, Sumi N; Donaldson, D James

    2014-05-20

    Chemical interactions at the air-ice interface are of great importance to local atmospheric chemistry but also to the concentrations of pollutants deposited onto natural snow and ice. However, the study of such processes has been hampered by the lack of general, surface-specific probes. Even seemingly basic chemical properties, such as the local concentration of chemical compounds, or the pH at the interface, have required the application of assumptions about solute distributions in frozen media. The measurements that have been reported have tended for the most part to focus on entire ice or snow samples, rather than strictly the frozen interface with the atmosphere. We have used glancing-angle laser spectroscopy to interrogate the air-ice interface; this has yielded several insights into the chemical interactions there. The linear fluorescence and Raman spectra thus measured have the advantage of easy interpretability; careful experimentation can limit their probe depth to that which is relevant to atmospheric heterogeneous processes. We have used these techniques to show that the environment at the interface between air and freshwater ice surfaces is distinct from that at the interface between air and liquid water. Acids such as HCl that adsorb to ice surfaces from the gas phase result in significantly different pH responses than those at liquid water surfaces. Further, the solvation of aromatic species is suppressed at freshwater ice surfaces compared with that at liquid water surfaces, leading to extensive self-association of aromatics at ice surfaces. Photolysis kinetics of these species are much faster than at liquid water surfaces; this can sometimes (but not always) be explained by red shifts in the absorption spectra of self-associated aromatics increasing the extent to which solar radiation is absorbed. The environment presented by frozen saltwater surfaces, in contrast, appears to be reasonably well-described by liquid water. The extent of hydrogen

  11. Insights into key factors controlling GO stability in natural surface waters.

    Science.gov (United States)

    Gao, Yang; Ren, Xuemei; Tan, Xiaoli; Hayat, Tasawar; Alsaedi, Ahmed; Chen, Changlun

    2017-08-05

    The effects of pH, cations (Na(+), K(+), Mg(2+), Ca(2+) and Al(3+)), and anions (Cl(-), HCO3(-), HPO4(2-) and SO4(2-)) on graphene oxide (GO) stability were investigated to address the current limitations in the knowledge regarding the stability of GO in natural surface water and its underlying mechanism. The threshold values of cations that destabilize GO were obtained and affected by both pH and anions. By employing elemental mapping and studying the effects of polyacrylic acid (PAA) on GO sedimentation and the re-dispersion of GO aggregates, we find that the GO aggregates induced by Na(+) and K(+) via electric double layer suppression and by Ca(2+) and Al(3+) via strong complxing are difficult to re-disperse completely. Specifically, more PAA is needed to re-disperse GO aggregates than to stabilize GO, which suggests that after GO binds with heavy metal ions. It is less likely to be transported over a long distance even in natural water that are rich in natural organic matter. Finally, we find that the key factor controlling GO sedimentation in natural surface waters is its binding with Mg(2+) and Ca(2+). This study is expected to provide critical knowledge to more accurately predict the fate of GO in natural surface aquatic environments. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Solar light (hv) and H2O2/hv photo-disinfection of natural alkaline water (pH 8.6) in a compound parabolic collector at different day periods in Sahelian region

    OpenAIRE

    Ndounla, J.; Pulgarin, C

    2015-01-01

    The photo-disinfection of natural alkaline surface water (pH 8.6 +/- 0.3) for drinking purposes was carried out under solar radiation treatments. The enteric bacteria studied were the wild total coliforms/Escherichia coli (10(4) CFU/ml) and Salmonella spp. (10(4) CFU/ml) naturally present in the water. The photo-disinfection of a 25-l water sample was carried out in a solar compound parabolic collector (CPC) in the absence and in the presence of hydrogen peroxide (H2O2). The addition of H2O2 ...

  13. Evaluation of the potentials of humic acid removal in water by gas phase surface discharge plasma.

    Science.gov (United States)

    Wang, Tiecheng; Qu, Guangzhou; Ren, Jingyu; Yan, Qiuhe; Sun, Qiuhong; Liang, Dongli; Hu, Shibin

    2016-02-01

    Degradation of humic acid (HA), a predominant type of natural organic matter in ground water and surface waters, was conducted using a gas phase surface discharge plasma system. HA standard and two surface waters (Wetland, and Weihe River) were selected as the targets. The experimental results showed that about 90.9% of standard HA was smoothly removed within 40 min's discharge plasma treatment at discharge voltage 23.0 kV, and the removal process fitted the first-order kinetic model. Roles of some active species in HA removal were studied by evaluating the effects of solution pH and OH radical scavenger; and the results presented that O3 and OH radical played significant roles in HA removal. Scanning electron microscope (SEM) and FTIR analysis showed that HA surface topography and molecular structure were changed during discharge plasma process. The mineralization of HA was analyzed by UV-Vis spectrum, dissolved organic carbon (DOC), specific UV absorbance (SUVA), UV absorption ratios, and excitation-emission matrix (EEM) fluorescence. The formation of disinfection by-products during HA sample chlorination was also identified, and CHCl3 was detected as the main disinfection by-product, but discharge plasma treatment could suppress its formation to a certain extent. In addition, approximately 82.3% and 67.9% of UV254 were removed for the Weihe River water and the Wetland water after 40 min of discharge plasma treatment.

  14. Oxide/Water Interfaces: How the Surface Chemistry Modifies the Electronic Energy Alignment

    Science.gov (United States)

    Sprik, Michiel

    2014-03-01

    The minimum of the d-electron conduction band of an aqueous transition metal oxide electrode is typically no more than a few 100 mV away from the standard hydrogen electrode (SHE). Because of this favourable alignment of the electronic energy levels (near) metallic transition metal oxides with partly filled d bands can be used as electrocatalysts while the compounds with finite electronic gap can be used as photocatalysts. However, because of their ionic character, transition metal-oxide surfaces also show amphiphilic acid-base activity. At low pH the basic sites are protonated and at high pH the acidic sites deprotonated creating an electrical double layer with corresponding surface potential. The alignment of the electronic energy levels, and by implication their redox activity, is therefore pH dependent. In fact, even in absence of protonic surface charge, the coordination with water molecules is already capable of shifting the electronic energy levels of the oxide by 1 eV or more. Computation of the electronic energies in transition metal oxide electrodes requires therefore a detailed modeling of their aqueous surface chemistry. The solvation energy of the proton is the common energy reference for both redox potentials on the SHE scale and acidity constants (pKa). Computation of the H+ solvation energy is therefore a key component in a unified treatment of redox and acid-base chemistry. In this talk we outline the Density Functional Theory based Molecular Dynamics (DFTMD) method we have developed for this purpose. The central tool of our approach is a method for reversible insertion of protons in the aqueous part of the DFTMD model system. As an illustration we discuss the application to the rutile TiO2/water and MnO2/water interface.

  15. Surface Passivation of GaN Nanowires for Enhanced Photoelectrochemical Water-Splitting

    KAUST Repository

    Varadhan, Purushothaman

    2017-02-08

    Hydrogen production via photoelectrochemical water-splitting is a key source of clean and sustainable energy. The use of one-dimensional nanostructures as photoelectrodes is desirable for photoelectrochemical water-splitting applications due to the ultralarge surface areas, lateral carrier extraction schemes, and superior light-harvesting capabilities. However, the unavoidable surface states of nanostructured materials create additional charge carrier trapping centers and energy barriers at the semiconductor-electrolyte interface, which severely reduce the solar-to-hydrogen conversion efficiency. In this work, we address the issue of surface states in GaN nanowire photoelectrodes by employing a simple and low-cost surface treatment method, which utilizes an organic thiol compound (i.e., 1,2-ethanedithiol). The surface-treated photocathode showed an enhanced photocurrent density of −31 mA/cm at −0.2 V versus RHE with an incident photon-to-current conversion efficiency of 18.3%, whereas untreated nanowires yielded only 8.1% efficiency. Furthermore, the surface passivation provides enhanced photoelectrochemical stability as surface-treated nanowires retained ∼80% of their initial photocurrent value and produced 8000 μmol of gas molecules over 55 h at acidic conditions (pH ∼ 0), whereas the untreated nanowires demonstrated only <4 h of photoelectrochemical stability. These findings shed new light on the importance of surface passivation of nanostructured photoelectrodes for photoelectrochemical applications.

  16. Surface Passivation of GaN Nanowires for Enhanced Photoelectrochemical Water-Splitting.

    Science.gov (United States)

    Varadhan, Purushothaman; Fu, Hui-Chun; Priante, Davide; Retamal, Jose Ramon Duran; Zhao, Chao; Ebaid, Mohamed; Ng, Tien Khee; Ajia, Idirs; Mitra, Somak; Roqan, Iman S; Ooi, Boon S; He, Jr-Hau

    2017-03-08

    Hydrogen production via photoelectrochemical water-splitting is a key source of clean and sustainable energy. The use of one-dimensional nanostructures as photoelectrodes is desirable for photoelectrochemical water-splitting applications due to the ultralarge surface areas, lateral carrier extraction schemes, and superior light-harvesting capabilities. However, the unavoidable surface states of nanostructured materials create additional charge carrier trapping centers and energy barriers at the semiconductor-electrolyte interface, which severely reduce the solar-to-hydrogen conversion efficiency. In this work, we address the issue of surface states in GaN nanowire photoelectrodes by employing a simple and low-cost surface treatment method, which utilizes an organic thiol compound (i.e., 1,2-ethanedithiol). The surface-treated photocathode showed an enhanced photocurrent density of -31 mA/cm(2) at -0.2 V versus RHE with an incident photon-to-current conversion efficiency of 18.3%, whereas untreated nanowires yielded only 8.1% efficiency. Furthermore, the surface passivation provides enhanced photoelectrochemical stability as surface-treated nanowires retained ∼80% of their initial photocurrent value and produced 8000 μmol of gas molecules over 55 h at acidic conditions (pH ∼ 0), whereas the untreated nanowires demonstrated only surface passivation of nanostructured photoelectrodes for photoelectrochemical applications.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  1. Quality of surface water in Missouri, water year 2015

    Science.gov (United States)

    Barr, Miya N.; Heimann, David C.

    2016-11-14

    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 water year 2015 (October 1, 2014, through September 30, 2015), 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 streamflows, monthly mean streamflows, and 7-day low flows is presented.

  2. Significantly improving trace thallium removal from surface waters during coagulation enhanced by nanosized manganese dioxide.

    Science.gov (United States)

    Huangfu, Xiaoliu; Ma, Chengxue; Ma, Jun; He, Qiang; Yang, Chun; Jiang, Jin; Wang, Yaan; Wu, Zhengsong

    2017-02-01

    Thallium (Tl) is an element of high toxicity and significant accumulation in human body. There is an urgent need for the development of appropriate strategies for trace Tl removal in drinking water treatment plants. In this study, the efficiency and mechanism of trace Tl (0.5 μg/L) removal by conventional coagulation enhanced by nanosized manganese dioxide (nMnO2) were explored in simulated water and two representative surface waters (a river water and a reservoir water obtained from Northeast China). Experimental results showed that nMnO2 significantly improve Tl(I) removal from selected waters. The removal efficiency was dramatically higher in the simulated water, demonstrating by less than 0.1 μg/L Tl residual. The enhancement of trace Tl removal in the surface waters decreased to a certain extent. Both adjusting water pH to alkaline condition and preoxidation of Tl(I) to Tl(III) benefit trace Tl removal from surface waters. Data also indicated that competitive cation of Ca(2+) decreased the efficiency of trace Tl removal, resulting from the reduction of Tl adsorption on nMnO2. Humic acid could largely low Tl removal efficiency during nMnO2 enhanced coagulation processes. Trace elemental Tl firstly adsorbed on nMnO2 and then removed accompanying with nMnO2 settling. The information obtained in the present study may provide a potential strategy for drinking water treatment plants threatened by trace Tl.

  3. Selected elements in surface waters of Antarctica and their relations with the natural environment

    Directory of Open Access Journals (Sweden)

    Arkadiusz Nędzarek

    2014-03-01

    Full Text Available The aim of the study was to specify the concentration of selected chemical elements in surface waters of King George Island, off the western coast of the Antarctic Peninsula. The research encompassed six streams, a lake and an artificial water reservoir located on the western coast of Admiralty Bay. Measured hydrochemical parameters included pH, conductivity, total dissolved solids (TDS, and total and dissolved forms elements such as Al, Co, Ni, Cu, Zn, Cd, Pb, Mn, Fe, As and Se. The values of pH, conductivity and TDS had the following ranges: 6.09–8.21, 6.0–875 µS cm−1 and 7.0–975 mg/L, respectively, and were typical for surface waters of Antarctica. Wide disparities were discovered regarding concentrations of the investigated elements, ranging from <0.01 µg/L for Cd to 510 µg/L for Fe, and differing from one water body to another. The investigated elements are discussed with reference to environmental conditions and anthropogenic factors. Concentrations of total and dissolved forms of elements are considered in connection with the composition of soil in their surroundings and with atmospheric deposition, mostly such as that took place locally. The increased levels of Pb and Zn concentrations in the immediate proximity of a research station suggested anthropogenic contamination.

  4. Role of water in polymer surface modification using organosilanes

    Science.gov (United States)

    Thallapalle, Pradeep Kumar; Zhang Newby, Bi-Min

    2002-03-01

    In general, polymers exhibit excellent bulk properties but may not possess specific surface properties for successful applications in biomaterials and nanotechnology. Surface modification of polymers with the self-assembled monolayers (SAMs) of organosilanes - ‘Silanization’ - is an attractive approach to alter surface properties without altering the polymer’s desired bulk properties. However, a pretreatment such as exposure to UV/O or plasma is normally required to generate active surface groups prior to silanization. These pretreatments cause undesirable surface changes such as severe surface roughening and excessive surface damage. Recent studies in silanization suggest that the presence of water or OH groups on the surface is essential to form SAMs. In this study we investigated the importance of surface water layer and OH groups in the formation of SAMs for a variety of polymers. The pre and post-modified polymers were examined using fourier transform infrared spectrometry, scanning probe microscopy and contact angle measurements. The results show that organosilanes can be grafted to a polymer surface as long as a water layer can be physisorbed to the surface or the polymer itself contains OH groups. However the monolayers formed are less organized compared to those formed on silicon wafers due to the amorphous nature of the polymers.

  5. Evaluation of water quality and hydrogeochemistry of surface and groundwater, Tiruvallur District, Tamil Nadu, India

    Science.gov (United States)

    Krishna Kumar, S.; Hari Babu, S.; Eswar Rao, P.; Selvakumar, S.; Thivya, C.; Muralidharan, S.; Jeyabal, G.

    2017-09-01

    Water quality of Tiruvallur Taluk of Tiruvallur district, Tamil Nadu, India has been analysed to assess its suitability in relation to domestic and agricultural uses. Thirty water samples, including 8 surface water (S), 22 groundwater samples [15 shallow ground waters (SW) and 7 deep ground waters (DW)], were collected to assess the various physico-chemical parameters such as Temperature, pH, Electrical conductivity (EC), Total dissolved solids (TDS), cations (Ca, Mg, Na, K), anions (CO3, HCO3, Cl, SO4, NO3, PO4) and trace elements (Fe, Mn, Zn). Various irrigation water quality diagrams and parameters such as United states salinity laboratory (USSL), Wilcox, sodium absorption ratio (SAR), sodium percentage (Na %), Residual sodium carbonate (RSC), Residual Sodium Bicarbonate (RSBC) and Kelley's ratio revealed that most of the water samples are suitable for irrigation. Langelier Saturation Index (LSI) values suggest that the water is slightly corrosive and non-scale forming in nature. Gibbs plot suggests that the study area is dominated by evaporation and rock-water dominance process. Piper plot indicates the chemical composition of water, chiefly controlled by dissolution and mixing of irrigation return flow.

  6. Evaluation of water quality and hydrogeochemistry of surface and groundwater, Tiruvallur District, Tamil Nadu, India

    Science.gov (United States)

    Krishna Kumar, S.; Hari Babu, S.; Eswar Rao, P.; Selvakumar, S.; Thivya, C.; Muralidharan, S.; Jeyabal, G.

    2016-07-01

    Water quality of Tiruvallur Taluk of Tiruvallur district, Tamil Nadu, India has been analysed to assess its suitability in relation to domestic and agricultural uses. Thirty water samples, including 8 surface water (S), 22 groundwater samples [15 shallow ground waters (SW) and 7 deep ground waters (DW)], were collected to assess the various physico-chemical parameters such as Temperature, pH, Electrical conductivity (EC), Total dissolved solids (TDS), cations (Ca, Mg, Na, K), anions (CO3, HCO3, Cl, SO4, NO3, PO4) and trace elements (Fe, Mn, Zn). Various irrigation water quality diagrams and parameters such as United states salinity laboratory (USSL), Wilcox, sodium absorption ratio (SAR), sodium percentage (Na %), Residual sodium carbonate (RSC), Residual Sodium Bicarbonate (RSBC) and Kelley's ratio revealed that most of the water samples are suitable for irrigation. Langelier Saturation Index (LSI) values suggest that the water is slightly corrosive and non-scale forming in nature. Gibbs plot suggests that the study area is dominated by evaporation and rock-water dominance process. Piper plot indicates the chemical composition of water, chiefly controlled by dissolution and mixing of irrigation return flow.

  7. SWFSC FED Mid Water Trawl Juvenile Rockfish Survey, Surface Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — SWFSC FED Mid Water Trawl Juvenile Rockfish Survey: Station Information and Surface Data. Surveys have been conducted along the central California coast in May/June...

  8. Treatability of South African surface waters by enhanced coagulation

    African Journals Online (AJOL)

    2013-06-05

    Jun 5, 2013 ... The majority of South African inland surface water sources are compromised due to a ... minimising residual coagulant, minimising sludge production .... included as being indicative of the worst effects of indirect reuse.

  9. Second Inflection Point of the Surface Tension of Water

    Science.gov (United States)

    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.

  10. Impact of alginate concentration on the stability of agglomerates made of TiO{sub 2} engineered nanoparticles: Water hardness and pH effects

    Energy Technology Data Exchange (ETDEWEB)

    Loosli, Frédéric, E-mail: frederic.loosli@unige.ch [University of Geneva, Section des Sciences de la Terre et de l’Environnement, Group of Environmental Physical Chemistry, F.-A. Forel Institute (Switzerland); Coustumer, Philippe Le, E-mail: philippe.le-coustumer@u-bordeaux1.fr [Université Bordeaux 3, EA 4592 Géoressources & Environnement, ENSEGID (France); Stoll, Serge, E-mail: serge.stoll@unige.ch [University of Geneva, Section des Sciences de la Terre et de l’Environnement, Group of Environmental Physical Chemistry, F.-A. Forel Institute (Switzerland)

    2015-01-15

    The stability of engineered nanoparticles in natural aquatic systems is of high interest for environmental risk assessment since an already important quantity of these reactive species is entering aquatic systems. In the present study, an important issue is addressed by investigating (i) the influence of divalent cations and water hardness (Mg{sup 2+} and Ca{sup 2+}) in agglomerate formation and (ii) alginate concentration effect on the stability TiO{sub 2} agglomerates formed in environmental freshwater conditions (pH and total hardness) representative of Lake Geneva, France/Switzerland. Our results indicate that the presence of alginate at typical natural organic matter concentration strongly modifies the stability of TiO{sub 2} nanoparticle agglomerates by inducing their partial disagglomeration. Significant TiO{sub 2} nanoparticles redispersion and formation of small fragments are expected to be induced by alginate adsorbed layer formed at the nanoparticle surfaces within the agglomerates.Graphical Abstract.

  11. pH driven addressing of silicon nanowires onto Si3N4/SiO2 micro-patterned surfaces

    Science.gov (United States)

    Cloarec, Jean-Pierre; Chevalier, Céline; Genest, Jonathan; Beauvais, Jacques; Chamas, Hassan; Chevolot, Yann; Baron, Thierry; Souifi, Abdelkader

    2016-07-01

    pH was used as the main driving parameter for specifically immobilizing silicon nanowires onto Si3N4 microsquares at the surface of a SiO2 substrate. Different pH values of the coating aqueous solution enabled to experimentally distribute nanowires between silicon nitride and silicon dioxide: at pH 3 nanowires were mainly anchored on Si3N4; they were evenly distributed between SiO2 and Si3N4 at pH 2.8; and they were mainly anchored on SiO2 at pH 2. A theoretical model based on DLVO theory and surface protonation/deprotonation equilibria was used to study how, in adequate pH conditions, Si nanowires could be anchored onto specific regions of a patterned Si3N4/SiO2 surface. Instead of using capillary forces, or hydrophilic/hydrophobic contrast between the two types of materials, the specificity of immobilization could rely on surface electric charge contrasts between Si3N4 and SiO2. This simple and generic method could be used for addressing a large diversity of nano-objects onto patterned substrates.

  12. Analysis and occurrence of seven artificial sweeteners in German waste water and surface water and in soil aquifer treatment (SAT).

    Science.gov (United States)

    Scheurer, Marco; Brauch, Heinz-J; Lange, Frank T

    2009-07-01

    A method for the simultaneous determination of seven commonly used artificial sweeteners in water is presented. The analytes were extracted by solid phase extraction using Bakerbond SDB 1 cartridges at pH 3 and analyzed by liquid chromatography electrospray ionization tandem mass spectrometry in negative ionization mode. Ionization was enhanced by post-column addition of the alkaline modifier Tris(hydroxymethyl)amino methane. Except for aspartame and neohesperidin dihydrochalcone, recoveries were higher than 75% in potable water with comparable results for surface water. Matrix effects due to reduced extraction yields in undiluted waste water were negligible for aspartame and neotame but considerable for the other compounds. The widespread distribution of acesulfame, saccharin, cyclamate, and sucralose in the aquatic environment could be proven. Concentrations in two influents of German sewage treatment plants (STPs) were up to 190 microg/L for cyclamate, about 40 microg/L for acesulfame and saccharin, and less than 1 microg/L for sucralose. Removal in the STPs was limited for acesulfame and sucralose and >94% for saccharin and cyclamate. The persistence of some artificial sweeteners during soil aquifer treatment was demonstrated and confirmed their environmental relevance. The use of sucralose and acesulfame as tracers for anthropogenic contamination is conceivable. In German surface waters, acesulfame was the predominant artificial sweetener with concentrations exceeding 2 microg/L. Other sweeteners were detected up to several hundred nanograms per liter in the order saccharin approximately cyclamate > sucralose.

  13. Shallow Water Propagation and Surface Reverberation Modeling

    Science.gov (United States)

    2012-09-30

    compare the results with experiment. This work will be used to help interpret field data of bistatic scattering from sea ice cover and calibrate...approximate analytical and numerical acoustic models used to compute bistatic scattering. The clouds of bubbles entrained at the sea surface by breaking...ABSTRACT SAR 18. NUMBER OF PAGES 7 19a. NAME OF RESPONSIBLE PERSON a. REPORT unclassified b. ABSTRACT unclassified c. THIS PAGE unclassified

  14. Tracer injection techniques in flowing surface water

    Science.gov (United States)

    Wörman, A.

    2009-04-01

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

  15. Macrophyte and pH buffering updates to the Klamath River water-quality model upstream of Keno Dam, Oregon

    Science.gov (United States)

    Sullivan, Annett B.; Rounds, Stewart A.; Asbill-Case, Jessica R.; Deas, Michael L.

    2013-01-01

    A hydrodynamic, water temperature, and water-quality model of the Link River to Keno Dam reach of the upper Klamath River was updated to account for macrophytes and enhanced pH buffering from dissolved organic matter, ammonia, and orthophosphorus. Macrophytes had been observed in this reach by field personnel, so macrophyte field data were collected in summer and fall (June-October) 2011 to provide a dataset to guide the inclusion of macrophytes in the model. Three types of macrophytes were most common: pondweed (Potamogeton species), coontail (Ceratophyllum demersum), and common waterweed (Elodea canadensis). Pondweed was found throughout the Link River to Keno Dam reach in early summer with densities declining by mid-summer and fall. Coontail and common waterweed were more common in the lower reach near Keno Dam and were at highest density in summer. All species were most dense in shallow water (less than 2 meters deep) near shore. The highest estimated dry weight biomass for any sample during the study was 202 grams per square meter for coontail in August. Guided by field results, three macrophyte groups were incorporated into the CE-QUAL-W2 model for calendar years 2006-09. The CE-QUAL-W2 model code was adjusted to allow the user to initialize macrophyte populations spatially across the model grid. The default CE-QUAL-W2 model includes pH buffering by carbonates, but does not include pH buffering by organic matter, ammonia, or orthophosphorus. These three constituents, especially dissolved organic matter, are present in the upper Klamath River at concentrations that provide substantial pH buffering capacity. In this study, CE-QUAL-W2 was updated to include this enhanced buffering capacity in the simulation of pH. Acid dissociation constants for ammonium and phosphoric acid were taken from the literature. For dissolved organic matter, the number of organic acid groups and each group's acid dissociation constant (Ka) and site density (moles of sites per mole of

  16. Idaho's surface-water-quality monitoring program: results from five sites sampled during water years 1990-93

    Science.gov (United States)

    ,

    1994-01-01

    In 1990, the U.S. Geological Survey (USGS), in cooperation with the Idaho Department of Health and Welfare, Division of Environmental Quality, implemented a statewide water-quality monitoring program in response to Idaho's antidegradation policy as required by the Clean Water Act. The program objective is to provide water-quality managers with a coordinated statewide network to detect trends in surface-water quality. The monitoring program includes the collection and analysis of samples from 56 sites on the Bear, Clearwater, Kootenai, Pend Oreille, Salmon, Snake, and Spokane Rivers and their tributaries (fig. 1). Samples are collected every year at 5 sites (annual sites) in drainage basins where long-term water-quality management is practiced, every other year at 19 sites (biennial sites) in basins where land and water uses change slowly, and every third year at 32 sites (triennial sites) where future development may affect water quality. Each year, 25 of the 56 sites are sampled. This report discusses results of sampling at five annual sites. During water years 1990-93 (October 1, 1989, through September 30, 1993), samples were collected six times per year at the five annual sites (fig. 1). Onsite analyses were made for discharge, specific conductance, pH, temperature, dissolved oxygen, bacteria (fecal coliform and fecal streptococci), and alkalinity. Laboratory analyses were made for major ions, nutrients, trace elements, and suspended sediment. Suspended sediment, nitrate, fecal coliform, trace elements, and specific conductance were used to characterize surface-water quality. Because concentrations of all trace elements except zinc were near detection limits, only zinc is discussed.

  17. Rhesus glycoprotein and urea transporter genes in rainbow trout embryos are upregulated in response to alkaline water (pH 9.7) but not elevated water ammonia.

    Science.gov (United States)

    Sashaw, Jessica; Nawata, Michele; Thompson, Sarah; Wood, Chris M; Wright, Patricia A

    2010-03-01

    Recent studies have shown that genes for the putative ammonia transporter, Rhesus glycoproteins (Rh) and the facilitated urea transporter (UT) are expressed before hatching in rainbow trout (Oncorhychus mykiss Walbaum) embryos. We tested the hypothesis that Rh and UT gene expressions are regulated in response to environmental conditions that inhibit ammonia excretion during early life stages. Eyed-up embryos (22 days post-fertilization (dpf)) were exposed to control (pH 8.3), high ammonia (1.70 mmol l(-1) NH4HCO3) and high pH (pH 9.7) conditions for 48h. With exposure to high water ammonia, ammonia excretion rates were reversed, tissue ammonia concentration was elevated by 9-fold, but there were no significant changes in mRNA expression relative to control embryos. In contrast, exposure to high water pH had a smaller impact on ammonia excretion rates and tissue ammonia concentrations, whereas mRNA levels for the Rhesus glycoprotein Rhcg2 and urea transporter (UT) were elevated by 3.5- and 5.6-fold, respectively. As well, mRNAs of the genes for H+ATPase and Na+/H+ exchanger (NHE2), associated with NH3 excretion, were also upregulated by 7.2- and 13-fold, respectively, in embryos exposed to alkaline water relative to controls. These results indicate that the Rhcg2, UT and associated transport genes are regulated in rainbow trout embryos, but in contrast to adults, there is no effect of high external ammonia at this stage of development.

  18. Cooperativity in Surface Bonding and Hydrogen Bonding of Water and Hydroxyl at Metal Surfaces

    DEFF Research Database (Denmark)

    Schiros, T.; Ogasawara, H.; Naslund, L. A.;

    2010-01-01

    of the mixed phase at metal surfaces. The surface bonding can be considered to be similar to accepting a hydrogen bond, and we can thereby apply general cooperativity rules developed for hydrogen-bonded systems. This provides a simple understanding of why water molecules become more strongly bonded...... to the surface upon hydrogen bonding to OH and why the OH surface bonding is instead weakened through hydrogen bonding to water. We extend the application of this simple model to other observed cooperativity effects for pure water adsorption systems and H3O+ on metal surfaces.......We examine the balance of surface bonding and hydrogen bonding in the mixed OH + H2O overlayer on Pt(111), Cu(111), and Cu(110) via density functional theory calculations. We find that there is a cooperativity effect between surface bonding and hydrogen bonding that underlies the stability...

  19. Super water repellent surface 'strictly' mimicking the surface structure of lotus leaf

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Tae Gon; Kim, Ho Young [Seoul National University, Seoul (Korea, Republic of); Yi, Jin Woo; Lee, Kwang Ryeol; Moon, Myoung Woon [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2009-07-01

    To achieve the hierarchy of roughness as observed in lotus leaves, most artificial water-repellent surfaces have nano-asperities on top of micropillars. However, observation of real lotus leaves through SEM reveals that nonoscale roughness covers the entire surface including the base as well as bumps. Thus we fabricate surfaces having the same hierarchical roughness structure as the lotus leaf by forming nanopillars on both micropillars and base. We compare the measures of water-repellency (static contact angle, contact angle hysteresis, and transition pressure between the Cassie and Wenzel states) of the lotus-like surface with those of surfaces having single micro- and nano- roughness. The results show that nanoscale roughness covering entire surface area leads to superior water-repellency to other surface roughness structures. We also give a theoretical consideration of this observation.

  20. Ramping of pH Across the Water-Pool of a Reverse Micelle.

    Science.gov (United States)

    Mukherjee, Puspal; Gupta, Shradhey; Rafiq, Shahnawaz; Yadav, Rajeev; Jain, Vipin Kumar; Raval, Jayraj; Sen, Pratik

    2016-02-23

    In this work, we have addressed the problem of "acidity" of the water-pool of a reverse micelle (RM) through the well-known inversion of sucrose reaction as a tool of investigation. This reaction has been performed inside positively and negatively charged RM and the rates are compared with that in bulk water. We propose that the buffer-like action in a water-pool is much stronger than expected earlier. The rate of sucrose hydrolysis slowed down in the negatively charged AOT reverse micelle while it sped up for the positively charged CTAB reverse micelle. However, temperature-dependent measurements showed that the activation energy remained the same for all the cases. It has been concluded that a proton gradient exists inside the water-pool of the reverse micelle and it determines the buffer-like action of the water-pool that persists until about 2 N of HCl in AOT RM of w(0) = 10.5.

  1. Simulation method for determining biodegradation in surface waters

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-07-01

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

  2. Chlorine stress mediates microbial surface attachment in drinking water systems.

    Science.gov (United States)

    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.

  3. An Efficient and Stable Hydrophobic Molecular Cobalt Catalyst for Water Electro-oxidation at Neutral pH

    KAUST Repository

    Chen, Ba-Tian

    2016-06-14

    The synthesis of a library of molecular water oxidation catalysts based on the Co complex of tris(2-benzimidazolylmethyl)amine is described. Hydrophobicity was identified as the key variable in mediating the catalytic competence of the complexes. The change in this parameter correlates with both the conformational mobility of the ligand core and the structural changes in the local solvent environment around the metal site. The optimal Co complex identified is hydrophobic, because of three semifluorinated side chains. It catalyzes water electro-oxidation efficiently at neutral pH, with an overpotential of 390 mV and a turnover frequency (TOF) of 1.83 s-1 in the absence of soluble Co salts. The catalyst can be immobilized through physisorption, and it remains stable in prolonged electrolysis experiments. © 2016 American Chemical Society.

  4. Water-clay surface interaction: A neutron scattering study

    Energy Technology Data Exchange (ETDEWEB)

    Sobolev, O., E-mail: sobolev38@gmail.com [LGIT, University of Grenoble and CNRS, BP 53-38041 Grenoble (France); Favre Buivin, F. [HES-SO Fribourg, Bd de Perolles 80-CP 32, CH-1705 Fribourg (Switzerland); Kemner, E.; Russina, M. [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Glienicker Strasse 100, D-14109 Berlin (Germany); Beuneu, B. [Laboratoire Leon Brillouin, C.E. Saclay, 91191 Gif sur Yvette (France); Cuello, G.J. [Institut Laue Langevin and Ikerbasque, 6, rue Jules Horowitz, BP 156, 38042 Grenoble, Cedex 9 (France); Charlet, L. [LGIT, University of Grenoble and CNRS, BP 53-38041 Grenoble (France)

    2010-08-23

    Graphical abstract: Interaction between water molecules and internal clay surfaces was studied by means of neutron diffraction and quasielastic neutron scattering. A hydrophobic cation, TMA{sup +} was used to reduce hydration of interlayer cations. - Abstract: The aim of this study was to investigate interaction between water molecules and internal clay surfaces by means of neutron diffraction and quasielastic neutron scattering. A hydrophobic cation, TMA{sup +} (NC{sub 4}H{sub 12}), was used to saturate the interlayer space of nontronite NAu-1 in order to reduce hydration of interlayer cations that could hinder the effects related to the clay-water interactions. The water content was low in order to reduce hydrogen bonding between water molecules. It was found that water molecules form strong hydrogen bonds with surface oxygen atoms of nontronite. The diffusion activation energy value E{sub a} = 29 {+-} 3 kJ/mol was obtained for water molecules hydrating the clay surface. These results confirm the assumption that surfaces of smectite clays with tetrahedral substitutions are hydrophilic.

  5. pH measuring of the interstitial water in high-density bentonite (2). Resin insertion method under controlled atmosphere (Progress report)

    Energy Technology Data Exchange (ETDEWEB)

    Oda, H.; Sato, K; Shibata, Masahiro [Japan Nuclear Cycle Development Inst., Tokai, Ibaraki (Japan). Tokai Works; Isogai, T.

    1999-03-01

    To measure the pH value of the interstitial water in the bentonite under the saturated pressure, a resin (adsorbent particles impregnated with pH indicator) was put between semi-permeable cellulose protection sheets and inserted into the bentonite and pH was measured using its color reaction. pH values (7-9) thus measured were found to depend on the pressure, the density at dried conditions and also on chemical constituents. The method was found to be applicable to rough estimate of elemental composition. (S. Ohno)

  6. Dropwise condensation rate of water breath figures on polymer surfaces having similar surface free energies

    Science.gov (United States)

    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.

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

    NARCIS (Netherlands)

    van Dijk, T.; van Staalduinen, M.A.; van der Sluijs, J.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 expe

  8. In vitro evaluation of topical fluoride pH and their effect on surface hardness of composite resin-based restorative materials.

    Science.gov (United States)

    Mujeeb, Abdul; Mansuri, Samir; Hussain, Seema Abid; Ramaswamy, Kausar

    2014-03-01

    The aim of the study was to correlate the pH and fluoride ion uptake with surface hardness of composite resin based restorative materials after topical fluoride application. Forty disks of each of test materials Composite (Filtek Z350XT, 3M ESPE, St Paul, MN, USA), Resin modified glass ionomer (Vitremer) and Compomer (Dyract AP) were made and ten disks of each material were placed in different test solutions - 1.23% APF gel, Sodium fluoride mouth rinse, 0.9% neutral fluoride and distilled water (Control group). After 36 hours of immersion, specimens were subjected to microhardness testing machine for evaluation of surface hardness. The greater hardness deterioration for all materials resulted with 1.23% APF gel when compared to the control group. Composite (Filtek Z350XT, 3M ESPE, St Paul, MN, USA) showed 17.13 VHN (control group 59.11 VHN). Vitremer showed 9.71 VHN (control group 37.71 VHN). Compomer showed 19.22 VHN (control group 36.78 VHN). 1.23% ApF gel significantly decreased hardness of composite, Vitremer and Compomer. Hardness deterioration associated with sodium fluoride mouth rinse and 0.9% neutral fluoride was less compared to 1.23% ApF gel.

  9. Effects of cyanobacterial-driven pH increases on sediment nutrient fluxes and coupled nitrification-denitrification in a shallow fresh water estuary

    Directory of Open Access Journals (Sweden)

    Y. Gao

    2012-07-01

    Full Text Available Summer cyanobacterial blooms caused an elevation in pH (9 to ~10.5 that lasted for weeks in the shallow and tidal-fresh region of the Sassafras River, a tributary of Chesapeake Bay (USA. Elevated pH promoted desorption of sedimentary inorganic phosphorus and facilitated conversion of ammonium (NH4+ to ammonia (NH3. In this study, we investigated pH effects on exchangeable NH4+ desorption, pore water diffusion and the flux rates of NH4+, soluble reactive phosphorus (SRP and nitrate (NO3, nitrification, denitrification, and oxygen consumption. Elevated pH enhanced desorption of exchangeable NH4+ through NH3 formation from both pore water and adsorbed NH4+ pools. Progressive penetration of high pH from the overlying water into sediment promoted the mobility of SRP and the release of total ammonium (NH4+ and NH3 into the pore water. At elevated pH levels, high sediment-water effluxes of SRP and total ammonium were associated with reduction of nitrification, denitrification and oxygen consumption rates. Alkaline pH and the toxicity of NH3 may inhibit nitrification in the thin aerobic zone, simultaneously constraining coupled nitrification–denitrification with limited NO3 supply and high pH penetration into the anaerobic zone. Geochemical feedbacks to pH elevation, such as enhancement of dissolved nutrient effluxes and reduction in N2 loss via denitrification, may enhance the persistence of cyanobacterial blooms in shallow water ecosystems.

  10. Surface waters of Illinois River basin in Arkansas and Oklahoma

    Science.gov (United States)

    Laine, L.L.

    1959-01-01

    flow during the 19-year base period, an impoundment at that site would have required a usable storage of 185,000 acre-ft to satisfy this demand during the drought years 1954-1956. The surface waters of the Illinois River basin are excellent quality being suitable for municipal, agriculture and most industrial uses. The average concentration of the dissolved mineral content is about 105 ppm (parts per million) and the hardness about 85 ppm. The water is slightly alkaline, having a range of pH values from 7.2 to 8.0. This report gives the estimated average discharge at gaging stations and approximations of average discharge at the State line for 3 sub-basins during the 19-year period October 1937 to September 1956, used as a base period in this report. Duration-of-flow data for various percentages of the time are shown for the period of observed record at the gaging stations; similar data are estimated for the selected base period. Storage requirements to sustain flow during the recent drought years are given for 3 stations. The streamflow records in the basin are presented on a monthly and annual basis through September 1957; provisional records for 3 stations are included through July 1958 for correlation purposes. Results of discharge measurements are given for miscellaneous sites where low-flow observations have been made. (available as photostat copy only)

  11. ATR-FTIR spectroscopy study of the influence of pH and contact time on the adhesion of Shewanella putrefaciens bacterial cells to the surface of hematite.

    Science.gov (United States)

    Elzinga, Evert J; Huang, Jen-How; Chorover, Jon; Kretzschmar, Ruben

    2012-12-04

    Attachment of live cells of Shewanella putrefaciens strain CN-32 to the surface of hematite (α-Fe(2)O(3)) was studied with in situ ATR-FTIR spectroscopy at variable pH (4.5-7.7) and contact times up to 24 h. The IR spectra indicate that phosphate based functional groups on the cell wall play an important role in mediating adhesion through formation of inner-sphere coordinative bonds to hematite surface sites. The inner-sphere attachment mode of microbial P groups varies with pH, involving either a change in protonation or in coordination to hematite surface sites as pH is modified. At all pH values, spectra collected during the early stages of adhesion show intense IR bands associated with reactive P-groups, suggestive of preferential coordination of P-moieties at the hematite surface. Spectra collected after longer sorption times show distinct frequencies from cell wall protein and carboxyl groups, indicating that bacterial adhesion occurring over longer time scales is to a lesser degree associated with preferential attachment of P-based bacterial functional groups to the hematite surface. The results of this study demonstrate that pH and reaction time influence cell-mineral interactions, implying that these parameters play an important role in determining cell mobility and biofilm formation in aqueous geochemical environments.

  12. Practical aspects of tritium measurement in ground and surface waters

    Energy Technology Data Exchange (ETDEWEB)

    Nitzsche, O. [Technische Univ. Bergakademie Freiberg (Germany). Inst. fuer Angewandte Physik; Hebert, D. [Technische Univ. Bergakademie Freiberg (Germany). Inst. fuer Angewandte Physik

    1997-03-01

    Tritium measurements are a powerful tool in hydrological and hydrogeological investigations for detecting mean residence times of several water reservoirs. Due to the low tritium activities in precipitation, ground and surface waters a low level measurement is necessary. Therefore often the liquid scintillation counting after an electrolytic enrichment of water is used. In this paper some practical aspects and problems of measurement are discussed and the problem of contamination in low level laboratories is shown. (orig.)

  13. Assessment of heavy metal river Ingulets surface water pollution

    OpenAIRE

    Trokhymenko, Ganna G.; Tsyhanyuk, Nina V.

    2017-01-01

    The low efficiency of implemented targeted programs to reduce the anthropogenic impact on hydroecosystem and overcoming its negative consequences demand a search for the optimal evidence reasonable decisions to improve the quality of Ingul river water basin for different economic sectors of water resources and the required number and suitable quality. Methodical bases of such research must be based on a detailed and comprehensive study of the hydrochemical regime and surface water quality. Th...

  14. Effects of Dimethyl Sulfoxide on Surface Water near Phospholipid Bilayers.

    Science.gov (United States)

    Lee, Yuno; Pincus, Philip A; Hyeon, Changbong

    2016-12-06

    Despite much effort to probe the properties of dimethyl sulfoxide (DMSO) solution, the effects of DMSO on water, especially near plasma membrane surfaces, still remain elusive. By performing molecular dynamics simulations at varying DMSO concentrations (XDMSO), we study how DMSO affects structural and dynamical properties of water in the vicinity of phospholipid bilayers. As proposed by a number of experiments, our simulations confirm that DMSO induces dehydration from bilayer surfaces and disrupts the H-bond structure of water. However, DMSO-enhanced water diffusivity at solvent-bilayer interfaces, an intriguing discovery reported by a spin-label measurement, is not confirmed in our simulations. To resolve this discrepancy, we examine the location of the spin label (Tempo) relative to the solvent-bilayer interface. In accord with the evidence in the literature, our simulations, which explicitly model Tempo-phosphatidylcholine, find that the Tempo moiety is equilibrated at ∼8-10 Å below the bilayer surface. Furthermore, the DMSO-enhanced surface-water diffusion is confirmed only when water diffusion is analyzed around the Tempo moiety that is immersed below the bilayer surface, which implies that the experimentally detected signal of water using Tempo stems from the interior of bilayers, not from the interface. Our analysis finds that the increase of water diffusion below the bilayer surface is coupled to the increase of area per lipid with an increasing XDMSO(≲10mol%). Underscoring the hydrophobic nature of the Tempo moiety, our study calls for careful re-evaluation of the use of Tempo in measurements on lipid bilayer surfaces. Copyright © 2016 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  15. An Ontology Design Pattern for Surface Water Features

    Energy Technology Data Exchange (ETDEWEB)

    Sinha, Gaurav [Ohio University; Mark, David [University at Buffalo (SUNY); Kolas, Dave [Raytheon BBN Technologies; Varanka, Dalia [U.S. Geological Survey, Rolla, MO; Romero, Boleslo E [University of California, Santa Barbara; Feng, Chen-Chieh [National University of Singapore; Usery, Lynn [U.S. Geological Survey, Rolla, MO; Liebermann, Joshua [Tumbling Walls, LLC; Sorokine, Alexandre [ORNL

    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.

  16. Rapid surface-water volume estimations in beaver ponds

    Science.gov (United States)

    Karran, Daniel J.; Westbrook, Cherie J.; Wheaton, Joseph M.; Johnston, Carol A.; Bedard-Haughn, Angela

    2017-02-01

    Beaver ponds are surface-water features that are transient through space and time. Such qualities complicate the inclusion of beaver ponds in local and regional water balances, and in hydrological models, as reliable estimates of surface-water storage are difficult to acquire without time- and labour-intensive topographic surveys. A simpler approach to overcome this challenge is needed, given the abundance of the beaver ponds in North America, Eurasia, and southern South America. We investigated whether simple morphometric characteristics derived from readily available aerial imagery or quickly measured field attributes of beaver ponds can be used to approximate surface-water storage among the range of environmental settings in which beaver ponds are found. Studied were a total of 40 beaver ponds from four different sites in North and South America. The simplified volume-area-depth (V-A-h) approach, originally developed for prairie potholes, was tested. With only two measurements of pond depth and corresponding surface area, this method estimated surface-water storage in beaver ponds within 5 % on average. Beaver pond morphometry was characterized by a median basin coefficient of 0.91, and dam length and pond surface area were strongly correlated with beaver pond storage capacity, regardless of geographic setting. These attributes provide a means for coarsely estimating surface-water storage capacity in beaver ponds. Overall, this research demonstrates that reliable estimates of surface-water storage in beaver ponds only requires simple measurements derived from aerial imagery and/or brief visits to the field. Future research efforts should be directed at incorporating these simple methods into both broader beaver-related tools and catchment-scale hydrological models.

  17. Sequential Washing with Electrolyzed Alkaline and Acidic Water Effectively Removes Pathogens from Metal Surfaces

    Science.gov (United States)

    Nakano, Yuichiro; Akamatsu, Norihiko; Mori, Tsuyoshi; Sano, Kazunori; Satoh, Katsuya; Nagayasu, Takeshi; Miyoshi, Yoshiaki; Sugio, Tomomi; Sakai, Hideyuki; Sakae, Eiji; Ichimiya, Kazuko; Hamada, Masahisa; Nakayama, Takehisa; Fujita, Yuhzo; Yanagihara, Katsunori; Nishida, Noriyuki

    2016-01-01

    Removal of pathogenic organisms from reprocessed surgical instruments is essential to prevent iatrogenic infections. Some bacteria can make persistent biofilms on medical devices. Contamination of non-disposable equipment with prions also represents a serious risk to surgical patients. Efficient disinfection of prions from endoscopes and other instruments such as high-resolution cameras remains problematic because these instruments do not tolerate aggressive chemical or heat treatments. Herein, we develop a new washing system that uses both the alkaline and acidic water produced by electrolysis. Electrolyzed acidic water, containing HCl and HOCl as active substances, has been reported to be an effective disinfectant. A 0.15% NaCl solution was electrolyzed and used immediately to wash bio-contaminated stainless steel model systems with alkaline water (pH 11.9) with sonication, and then with acidic water (pH 2.7) without sonication. Two bacterial species (Staphylococcus aureus and Pseudomonas aeruginosa) and a fungus (Candida albicans) were effectively removed or inactivated by the washing process. In addition, this process effectively removed or inactivated prions from the stainless steel surfaces. This washing system will be potentially useful for the disinfection of clinical devices such as neuroendoscopes because electrolyzed water is gentle to both patients and equipment and is environmentally sound. PMID:27223116

  18. Sequential Washing with Electrolyzed Alkaline and Acidic Water Effectively Removes Pathogens from Metal Surfaces.

    Science.gov (United States)

    Nakano, Yuichiro; Akamatsu, Norihiko; Mori, Tsuyoshi; Sano, Kazunori; Satoh, Katsuya; Nagayasu, Takeshi; Miyoshi, Yoshiaki; Sugio, Tomomi; Sakai, Hideyuki; Sakae, Eiji; Ichimiya, Kazuko; Hamada, Masahisa; Nakayama, Takehisa; Fujita, Yuhzo; Yanagihara, Katsunori; Nishida, Noriyuki

    2016-01-01

    Removal of pathogenic organisms from reprocessed surgical instruments is essential to prevent iatrogenic infections. Some bacteria can make persistent biofilms on medical devices. Contamination of non-disposable equipment with prions also represents a serious risk to surgical patients. Efficient disinfection of prions from endoscopes and other instruments such as high-resolution cameras remains problematic because these instruments do not tolerate aggressive chemical or heat treatments. Herein, we develop a new washing system that uses both the alkaline and acidic water produced by electrolysis. Electrolyzed acidic water, containing HCl and HOCl as active substances, has been reported to be an effective disinfectant. A 0.15% NaCl solution was electrolyzed and used immediately to wash bio-contaminated stainless steel model systems with alkaline water (pH 11.9) with sonication, and then with acidic water (pH 2.7) without sonication. Two bacterial species (Staphylococcus aureus and Pseudomonas aeruginosa) and a fungus (Candida albicans) were effectively removed or inactivated by the washing process. In addition, this process effectively removed or inactivated prions from the stainless steel surfaces. This washing system will be potentially useful for the disinfection of clinical devices such as neuroendoscopes because electrolyzed water is gentle to both patients and equipment and is environmentally sound.

  19. Multivariate statistical analysis of surface water chemistry: A case study of Gharasoo River, Iran

    Directory of Open Access Journals (Sweden)

    MH Sayadi

    2014-09-01

    Full Text Available Regional water quality is a hot spot in the environmental sciences for inconsistency of pollutants. In this paper, the surface water quality of the Gharasoo River in western Iran is assessed incorporating multivariate statistical techniques. Parameters like EC, TDS, pH, HCO3-, Cl-, SO4 2-, Ca2+, Mg2+ and Na+ were analyzed. Principal component and factor analysis is showed the parameters generated 3 significant factors, which explained 73.06% of the variance in data sets. Factor 1 may be derived from agricultural activities and subsequent release of EC, TDS, SO4 2- and Na+ to the water. Factor 2 could be influenced by domestic pollution and explained the deliverance of HCO3-, Cl- and Mg2+ into the water. Factor 3 contains hydro-geochemical variable Ca2+ and pH, originating from mineralization of the geological components of bed sediments and soils of watershed area. Likewise, the clustering analysis generated 3 groups of the stations as the groups had similar characteristic features. Pearson correlation analysis showed significant correlations between HCO3- and Mg2+ (0.775, Ca2+ (0.552 as well as TDS and Na+ (0.726. With reference to multivariate statistical analyses it can be concluded that the agricultural, domestic and hydro-geochemical sources are releasing the pollutants into the Gharasoo River water.

  20. Sequential Washing with Electrolyzed Alkaline and Acidic Water Effectively Removes Pathogens from Metal Surfaces.

    Directory of Open Access Journals (Sweden)

    Yuichiro Nakano

    Full Text Available Removal of pathogenic organisms from reprocessed surgical instruments is essential to prevent iatrogenic infections. Some bacteria can make persistent biofilms on medical devices. Contamination of non-disposable equipment with prions also represents a serious risk to surgical patients. Efficient disinfection of prions from endoscopes and other instruments such as high-resolution cameras remains problematic because these instruments do not tolerate aggressive chemical or heat treatments. Herein, we develop a new washing system that uses both the alkaline and acidic water produced by electrolysis. Electrolyzed acidic water, containing HCl and HOCl as active substances, has been reported to be an effective disinfectant. A 0.15% NaCl solution was electrolyzed and used immediately to wash bio-contaminated stainless steel model systems with alkaline water (pH 11.9 with sonication, and then with acidic water (pH 2.7 without sonication. Two bacterial species (Staphylococcus aureus and Pseudomonas aeruginosa and a fungus (Candida albicans were effectively removed or inactivated by the washing process. In addition, this process effectively removed or inactivated prions from the stainless steel surfaces. This washing system will be potentially useful for the disinfection of clinical devices such as neuroendoscopes because electrolyzed water is gentle to both patients and equipment and is environmentally sound.

  1. Integrated Water Flow Model (IWFM), A Tool For Numerically Simulating Linked Groundwater, Surface Water And Land-Surface Hydrologic Processes

    Science.gov (United States)

    Dogrul, E. C.; Brush, C. F.; Kadir, T. N.

    2006-12-01

    The Integrated Water Flow Model (IWFM) is a comprehensive input-driven application for simulating groundwater flow, surface water flow and land-surface hydrologic processes, and interactions between these processes, developed by the California Department of Water Resources (DWR). IWFM couples a 3-D finite element groundwater flow process and 1-D land surface, lake, stream flow and vertical unsaturated-zone flow processes which are solved simultaneously at each time step. The groundwater flow system is simulated as a multilayer aquifer system with a mixture of confined and unconfined aquifers separated by semiconfining layers. The groundwater flow process can simulate changing aquifer conditions (confined to unconfined and vice versa), subsidence, tile drains, injection wells and pumping wells. The land surface process calculates elemental water budgets for agricultural, urban, riparian and native vegetation classes. Crop water demands are dynamically calculated using distributed soil properties, land use and crop data, and precipitation and evapotranspiration rates. The crop mix can also be automatically modified as a function of pumping lift using logit functions. Surface water diversions and groundwater pumping can each be specified, or can be automatically adjusted at run time to balance water supply with water demand. The land-surface process also routes runoff to streams and deep percolation to the unsaturated zone. Surface water networks are specified as a series of stream nodes (coincident with groundwater nodes) with specified bed elevation, conductance and stage-flow relationships. Stream nodes are linked to form stream reaches. Stream inflows at the model boundary, surface water diversion locations, and one or more surface water deliveries per location are specified. IWFM routes stream flows through the network, calculating groundwater-surface water interactions, accumulating inflows from runoff, and allocating available stream flows to meet specified or

  2. High-resolution Imaging of pH in Alkaline Sediments and Water Based on a New Rapid Response Fluorescent Planar Optode.

    Science.gov (United States)

    Han, Chao; Yao, Lei; Xu, Di; Xie, Xianchuan; Zhang, Chaosheng

    2016-05-20

    A new dual-lumophore optical sensor combined with a robust RGB referencing method was developed for two-dimensional (2D) pH imaging in alkaline sediments and water. The pH sensor film consisted of a proton-permeable polymer (PVC) in which two dyes with different pH sensitivities and emission colors: (1) chloro phenyl imino propenyl aniline (CPIPA) and (2) the coumarin dye Macrolex(®) fluorescence yellow 10 GN (MFY-10 GN) were entrapped. Calibration experiments revealed the typical sigmoid function and temperature dependencies. This sensor featured high sensitivity and fast response over the alkaline working ranges from pH 7.5 to pH 10.5. Cross-sensitivity towards ionic strength (IS) was found to be negligible for freshwater when IS water associated with the photosynthesis of Vallisneria spiral species was also presented, suggesting that the sensor held great promise for the field applications.

  3. Nonzero Ideal Gas Contribution to the Surface Tension of Water.

    Science.gov (United States)

    Sega, Marcello; Fábián, Balázs; Jedlovszky, Pál

    2017-06-15

    Surface tension, the tendency of fluid interfaces to behave elastically and minimize their surface, is routinely calculated as the difference between the lateral and normal components of the pressure or, invoking isotropy in momentum space, of the virial tensor. Here we show that the anisotropy of the kinetic energy tensor close to a liquid-vapor interface can be responsible for a large part of its surface tension (about 15% for water, independent from temperature).

  4. Tenderness, pH and Water Activity (Aw of Spices Dried Meat on Various Concentrate of Ginger Extract (Zingiber Officinale Roscoe and Different Soaking Time

    Directory of Open Access Journals (Sweden)

    Akhadiyah Afrila

    2012-09-01

    Full Text Available The objectives of current research were to find out the concentrate of Ginger extract (Zingiber officinale Roscoe and different soaking time of to tenderness, pH, and water activity (Aw, microbial count and sensory evaluation of spices dried meat. The result showed that higher the ginger extract (Zingiber officinale Roscoe concentrate and longer the soaking time, it would give more tenderness, pH, and water activity (Aw to spices dried meat with 15% ginger extract (Zingiber officinale Roscoe extract and 20 minutes length of soaking time. Key Words : Dendeng, ginger, soaking time, tenderness, pH and Aw

  5. Characterization of Surface Water and Groundwater Quality in the Lower Tano River Basin Using Statistical and Isotopic Approach.

    Science.gov (United States)

    Edjah, Adwoba; Stenni, Barbara; Cozzi, Giulio; Turetta, Clara; Dreossi, Giuliano; Tetteh Akiti, Thomas; Yidana, Sandow

    2017-04-01

    Adwoba Kua- Manza Edjaha, Barbara Stennib,c,Giuliano Dreossib, Giulio Cozzic, Clara Turetta c,T.T Akitid ,Sandow Yidanae a,eDepartment of Earth Science, University of Ghana Legon, Ghana West Africa bDepartment of Enviromental Sciences, Informatics and Statistics, Ca Foscari University of Venice, Italy cInstitute for the Dynamics of Environmental Processes, CNR, Venice, Italy dDepartment of Nuclear Application and Techniques, Graduate School of Nuclear and Allied Sciences University of Ghana Legon This research is part of a PhD research work "Hydrogeological Assessment of the Lower Tano river basin for sustainable economic usage, Ghana, West - Africa". In this study, the researcher investigated surface water and groundwater quality in the Lower Tano river basin. This assessment was based on some selected sampling sites associated with mining activities, and the development of oil and gas. Statistical approach was applied to characterize the quality of surface water and groundwater. Also, water stable isotopes, which is a natural tracer of the hydrological cycle was used to investigate the origin of groundwater recharge in the basin. The study revealed that Pb and Ni values of the surface water and groundwater samples exceeded the WHO standards for drinking water. In addition, water quality index (WQI), based on physicochemical parameters(EC, TDS, pH) and major ions(Ca2+, Na+, Mg2+, HCO3-,NO3-, CL-, SO42-, K+) exhibited good quality water for 60% of the sampled surface water and groundwater. Other statistical techniques, such as Heavy metal pollution index (HPI), degree of contamination (Cd), and heavy metal evaluation index (HEI), based on trace element parameters in the water samples, reveal that 90% of the surface water and groundwater samples belong to high level of pollution. Principal component analysis (PCA) also suggests that the water quality in the basin is likely affected by rock - water interaction and anthropogenic activities (sea water intrusion). This

  6. Metropolitan Spokane Region Water Resources Study. Appendix A. Surface Water

    Science.gov (United States)

    1976-01-01

    the river as surface supply. This second area lies mostly north of the Spokane River extending up the val- ley known as Rathdrum Prairie and includes...4 10. 2-29 I .~ -A- IvA -4 -4 IS I rp4r 1-4 - 4NCs 4~ 10. 2- 3o * r~tar gg~wr 4 . fAPPENDIX I en00 -4 - r., 0 CM- WMC q ~~0 0r0 4. .44 . VFog 4102A3

  7. Water transport mechanism through open capillaries analyzed by direct surface modifications on biological surfaces

    Science.gov (United States)

    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. Stormwater Priority Pollutants Versus Surface Water Quality Criteria

    DEFF Research Database (Denmark)

    Eriksson, Eva; Ledin, Anna; Baun, Anders

    2011-01-01

    Stormwater in urban areas comprises of a substantial part of the urban water cycle, dominating the flow in many small urban streams, and the pollution levels are sizeable. No stormwater quality criteria were found here and no European or national emission limit values exist. Stormwater pollutants...... however are present in levels exceeding most of the regulated surface water quality criteria and environmental quality standards. Therefore catchment characterisation is needed to chose suitable treatment prior to discharge into receiving surface waters, as the mixing may be insufficient in small streams....

  9. REMOVAL OF ORGANIC MATTER FROM SURFACE WATER USING COAGULANTS WITH VARIOUS BASICITY

    Directory of Open Access Journals (Sweden)

    Lidia Dąbrowska

    2016-07-01

    Full Text Available Humic substances are a natural admixture of surface water and determine the level of organic pollution of water and colour intensity. Application of coagulation process in surface water treatment allows for decrease turbidity and colour of water, as well as organic matter content. In Poland most drinking water treatment plants use aluminium sulphate as a coagulant. Research works on pre-hydrolysed coagulants, e.g. polyaluminium chlorides (general formula Aln(OHmCl3n-m are also carried out. The aim of this study was to evaluate the effectiveness of the coagulation process using polyaluminium chlorides with different basicity, in reducing the level of pollution of surface water with organic substances. Apart from the typical indicators used to evaluate the content of organic compounds, the potential for trihalomethanes formation THM-FP was also determined. The influence of the type of coagulant (low, medium, highly alkaline on the efficiency of organic compound removal, determined as total organic carbon TOC, oxidisability OXI, absorbance UV254, was stated. Under the conditions of the coagulation (pH 7.2-7.4, temperature of 19-21°C, the best results were obtained using highly alkaline polyaluminium chlorides PAX-XL19F, PAX-XL1905 and PAX-XL1910S, decrease in TOC and OXI by 43-46%, slightly worse - 40-41% using low alkaline PAX18. Using the medium alkaline coagulants PAX-XL61 and PAXX-XL69, 30-35% removal of organic matter was obtained. Despite various effects of dissolved organic carbon removal, depending on the used coagulant, THM-FP in purified water did not differ significantly and ranged from 10.0 to 10.9 mgCHCl3 m-3. It was by 37-42% lower than in surface water.

  10. Atrazine, triketone herbicides, and their degradation products in sediment, soil and surface water samples in Poland.

    Science.gov (United States)

    Barchanska, Hanna; Sajdak, Marcin; Szczypka, Kornelia; Swientek, Angelika; Tworek, Martyna; Kurek, Magdalena

    2017-01-01

    The aim of this study was to monitor the sediment, soil and surface water contamination with selected popular triketone herbicides (mesotrione (MES) and sulcotrione(SUL)), atrazine (ATR) classified as a possible carcinogen and endocrine disrupting chemical, as well as their degradation products, in Silesia (Poland). Seventeen sediment samples, 24 soil samples, and 64 surface water samples collected in 2014 were studied. After solid-liquid extraction (SLE) and solid phase extraction (SPE), analytes were determined by high-performance liquid chromatography (HPLC) with diode array detection (DAD). Ten years after the withdrawal from the use, ATR was not detected in any of the collected samples; however, its degradation products are still present in 41 % of sediment, 71 % of soil, and 8 % of surface water samples. SUL was determined in 85 % of soil samples; its degradation product (2-chloro-4-(methylosulfonyl) benzoic acid (CMBA)) was present in 43 % of soil samples. In 17 % of sediment samples, CMBA was detected. Triketones were detected occasionally in surface water samples. The chemometric analysis (clustering analysis (CA), single-factor analysis of variance (ANOVA), N-Way ANOVA) was applied to find relations between selected soil and sediment parameters and herbicides concentration. In neither of the studied cases a statistically significant relationship between the concentrations of examined herbicides, their degradation products and soil parameters (organic carbon (OC), pH) was observed.

  11. Surface Water Resources Response to Climate Changes in Jilin Province

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    [Objective] The response of surface water resources on climate changes was studied.[Method] By dint of monthly average temperature and precipitation in 45 meteorological stations in Jilin Province from 1960 to 2000,monthly runoff in 56 hydrological stations in Songhuajiang and Liaohe region,the surface runoff change and the response of surface water resources to climate change in 41 years were expounded.[Result] The runoff of Songliao region was limited during 1960s and 1970s.It began to increase slowly in ...

  12. In situ Determination of Pore-water pH in Reducing Sediments near Methane Seeps and Vents by Laser Raman Spectroscopy

    Science.gov (United States)

    Peltzer, E. T.; Walz, P. M.; Luna, M.; Zhang, X.; Brewer, P. G.

    2015-12-01

    Sediments near methane vents and seeps are often anoxic in nature due to the microbial oxidation of organic matter. When the pore-water oxygen is consumed, the microbial population resorts to using sulfate as the terminal electron receptor. For the anaerobic oxidation of methane, the net reaction is: CH4 + SO42- = HCO3- + HS- + H2O. Hydrogen sulfide produced by this reaction dissociates into bisulfide in proportion to the pore-water pH. Since the first pK of H2S is about 7 and close to the in situ pore-water pH, it satisfies the criteria for a useful pH indicating dye. Although the two forms of hydrogen sulfide are not visually discernable by the human eye, these two forms have distinct Raman spectra and thus can be easily quantified using an in situ spectrometer. The relative Raman cross-sections of the hydrogen sulfide species were determined in the laboratory across a range of relevant pH values and at the approximate salinity (ionic strength) and temperature of deep-sea pore waters. With this calibration, it is simple to compute the pore-water pH from the relative abundance of the two sulfide species: pH = pK1 + log10([HS-]/[H2S]). Pore-water profiles were investigated at several sites in the Santa Monica basin around methane mounds, gas vents and cold seeps. A titanium pore-water probe with a stainless steel frit was used to filter and collect pore-water samples at 5-10 cm intervals in the top 50-60 cm of sediment. Filtration and collection of the pore-water samples was usually accomplished in 5-10 minutes, with acquisition of the laser Raman spectra requiring only 2-4 minutes additional time. Vertical profiles of sulfate, total sulfide (H2S + HS-), methane and pH were collected simultaneously using the laser Raman spectrometer and pore-water profile sampler. Sulfate was observed to decrease from seawater concentrations to below detection limits while both methane and total sulfide increased proportionally to the sulfate loss. Once total sulfide concentrations

  13. Monitoring of ph, redox and turbidity in a water treatment plant using WSN with ZIGBEE technology

    Directory of Open Access Journals (Sweden)

    Gerson Fonseca-Gonzaléz

    2014-05-01

    Full Text Available This paper presents the design of a WSN using Zigbee technology (Standart IEEE 802.15.4, With the help of the XBee of Maxtream modules the communication is carried out between a remote water treatment plant towards a ccordinator node. The acqired data are entered to a microcontroller which takes care of the processing to be able to transmit and visualized under a graphical user interface in Matlab

  14. The Proposed Surface Water and Ocean Topography (SWOT) Mission

    Science.gov (United States)

    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.

  15. The influence of lithology on surface water sources | Science ...

    Science.gov (United States)

    Understanding the temporal and spatial variability of surface water sources within a basin is vital to our ability to manage the impacts of climate variability and land cover change. Water stable isotopes can be used as a tool to determine geographic and seasonal sources of water at the basin scale. Previous studies in the Coastal Range of Oregon reported that the variation in the isotopic signatures of surface water does not conform to the commonly observed “rainout effect”, which exhibits a trend of increasing isotopic depletion with rising elevation. The primary purpose of this research is to investigate the mechanisms governing seasonal and spatial variations in the isotopic signature of surface waters within the Marys River Basin, located in the leeward side of the Oregon Coastal Range. Surface water and precipitation samples were collected every 2-3 weeks for isotopic analysis of δ18O and δ2H for one year. Results indicate a significant difference in isotopic signature between watersheds underlain by basalt and sandstone. The degree of separation was the most distinct during the summer when low flows reflect deeper groundwater sources, whereas isotopic signatures during the rainy season (fall and winter) showed a greater degree of similarity between the two lithologies. This indicates that baseflow within streams drained by sandstone versus basalt is being supplied from two distinctly separate water sources. In addition, Marys River flow at the outle

  16. Surface water waves due to an oscillatory wavemaker in the presence of surface tension

    Directory of Open Access Journals (Sweden)

    B. N. Mandal

    1992-01-01

    Full Text Available The initial value problem of generation of surface water waves by a harmonically oscillating plane vertical wavemaker in an infinite incompressible fluid under the action of gravity and surface tension is investigated. In the asymptotic evaluation of the free surface depression for large time and distance, the contribution to the integral by stationary phase method gives rise to transient component of the free surface depression while the contribution from the poles give rise to steady state component. It is observed that the presence of surface tension sometimes changes the qualitative nature of the transient component of free surface depression.

  17. Surface tension isotherms of the dioxane-acetone-water and glycerol-ethanol-water ternary systems

    Science.gov (United States)

    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.

  18. Supplementary report on surface-water and ground-water surveys, Nueces River Basin, Texas

    Science.gov (United States)

    Broadhurst, W.L.; Ellsworth, C.E.

    1950-01-01

    A report on the ground-water and surface-water surveys of the Nueces River Basin was included in a report by the Bureau of Reclamation, entitled "Comprehensive plan for water-resources development of the Nueces River Basin project planning report number 5-14.04-3, February 1946".

  19. Using IR Imaging of Water Surfaces for Estimating Piston Velocities

    Science.gov (United States)

    Gålfalk, M.; Bastviken, D.; Arneborg, L.

    2013-12-01

    The transport of gasses dissolved in surface waters across the water-atmosphere interface is controlled by the piston velocity (k). This coefficient has large implications for, e.g., greenhouse gas fluxes but is challenging to quantify in situ. At present, empirical k-wind speed relationships from a small number of studies and systems are often extrapolated without knowledge of model performance. It is therefore of interest to search for new methods for estimating k, and to compare the pros and cons of existing and new methods. Wind speeds in such models are often measured at a height of 10 meters. In smaller bodies of water such as lakes, wind speeds can vary dramatically across the surface through varying degrees of wind shadow from e.g. trees at the shoreline. More local measurements of the water surface, through wave heights or surface motion mapping, could give improved k-estimates over a surface, also taking into account wind fetch. At thermal infrared (IR) wavelengths water has very low reflectivity (depending on viewing angle) than can go below 1%, meaning that more than 99% is heat radiation giving a direct measurement of surface temperature variations. Using an IR camera at about 100 frames/s one could map surface temperature structures at a fraction of a mm depth even with waves present. In this presentation I will focus on IR imaging as a possible tool for estimating piston velocities. Results will be presented from IR field measurements, relating the motions of surface temperature structures to k calculated from other simultaneous measurements (flux chamber and ADV-Based Dissipation Rate), but also attempting to calculate k directly from the IR surface divergence. A relation between wave height and k will also be presented.

  20. Arsenic and major cation hydrogeochemistry of the Central Victorian (Australia) surface waters

    Institute of Scientific and Technical Information of China (English)

    Khawar SULTAN; Kim DOWLING

    2006-01-01

    This paper reports on the major cations(Ca, Mg, Na and K) and arsenic(As) compositions of surface waters collected from major creeks, rivers and lakes in Central Victoria (Australia). The surface waters were found to be neutral to alkaline (pH 6.7-9.4),oxidised (average redox potential (Eh) about 130 mV) and showed variable concentrations of dissolved ions (EC, about 51-4386 μS/cm). The concen- trations of dissolved major cations in surface waters were found to be in the order of Na>>Mg>Ca>K and in soils the contents of metals followed an order of abundance as: Ca>Mg>>K>Na. While Na was the least abundant in soils, it registered the highest dissolved cation in surface waters. Of the four major cations, the average concentration ofNa(98.7 mg/L) was attributed to the weathering of feldspars and atmospheric input. Relatively highly dissolved concentrations of Na and Mg compared with the world average values of rivers reflected the weathering of rock and soil minerals within the catchments.The As soil level is naturally high(linked to lithology) as reflected by high background soil values and mining operations are also considered to be a contributory factor. Under relatively alkaline-oxidative conditions low mobility of dissolved As (average about 7.9 μg/L) was observed in most of the surface waters with a few higher values(>15 μg/L) around a sewage disposal site and mine tailings.Arsenic in soils is slowly released into water under alkaline and/or lower Eh conditions. The efficient sink of Fe, Al and Mn oxides acts as a barrier against the As release under near neutral-oxidising conditions. High As content (average about 28.3 mg/kg) in soils was found to be associated with Fe-hydroxides as revealed by XRD and SEM analysis. The dissolved As concentration was found to be below the recommended maximum levels for recreational water in all surface waters(lakes and rivers) in the study area. Catchment lithology exerted the fundamental control on surface water chemistry

  1. Microbial Survey of Pennsylvania Surface Water Used for Irrigating Produce Crops.

    Science.gov (United States)

    Draper, Audrey D; Doores, Stephanie; Gourama, Hassan; LaBorde, Luke F

    2016-06-01

    Recent produce-associated foodborne illness outbreaks have been attributed to contaminated irrigation water. This study examined microbial levels in Pennsylvania surface waters used for irrigation, relationships between microbial indicator organisms and water physicochemical characteristics, and the potential use of indicators for predicting the presence of human pathogens. A total of 153 samples taken from surface water sources used for irrigation in southeastern Pennsylvania were collected from 39 farms over a 2-year period. Samples were analyzed for six microbial indicator organisms (aerobic plate count, Enterobacteriaceae, coliform, fecal coliforms, Escherichia coli, and enterococci), two human pathogens (Salmonella and E. coli O157), and seven physical and environmental characteristics (pH, conductivity, turbidity, air and water temperature, and sampling day and 3-day-accumulated precipitation levels). Indicator populations were highly variable and not predicted by water and environmental characteristics. Only five samples were confirmed positive for Salmonella, and no E. coli O157 was detected in any samples. Predictive relationships between microbial indicators and the occurrence of pathogens could therefore not be determined.

  2. Foulant characteristics comparison in recycling cooling water system makeup by municipal reclaimed water and surface water in power plant.

    Science.gov (United States)

    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. Molecular Dynamics Simulations of Water Nanodroplets on Silica Surfaces

    DEFF Research Database (Denmark)

    Zambrano, Harvey A; Walther, Jens Honore; Jaffe, Richard L.

    2009-01-01

    and DNA microarrays technologies.4,5,6,7,8 Although extensive experimental, theoretical and computational work has been devoted to study the nature of the interaction between silica and water,2,9-16 at the molecular level a complete understanding of silica-water systems has not been reached. Contact angle...... computations of water droplets on silica surfaces offers a useful fundamental and quantitative measurement in order to study chemical and physical properties of water-silica systems.3,16,17,18 For hydrophobic systems the static and dynamic properties of the fluid-solid interface are influenced by the presence...

  4. Surface Chemistry and Tribology of Copper Surfaces in Carbon Dioxide and Water Vapor Environments

    Science.gov (United States)

    2011-02-23

    progress). Simultaneous XAS and cyclic voltammetry of Cu in bicarbonate solutions under potentiostatic control at the Berkeley Synchrotron facility (Figure...bicarbonate ions that mimic the conditions of the wet brush-rotor contact. Electrochemical control of the surface by cyclic voltammetry makes it...the electrochemical modifications of Cu under potentiostat control and solution pH 3) Determine the loss of mass of Cu when in carbonate containing

  5. A Mechanism for Near-Surface Water Ice on Mars

    Science.gov (United States)

    Travis, B. J.; Feldman, W. C.; Maurice, S.

    2009-12-01

    Recent findings (e.g., Byrne et al, 2009) indicate that water ice lies very close to the surface at mid-latitudes on Mars. Re-interpretation of neutron and gamma-ray data is consistent with water ice buried less than a meter or two below the surface. Hydrothermal convection of brines provides a mechanism for delivering water to the near-surface. Previous numerical and experimental studies with pure water have indicated that hydrothermal circulation of pore water should be possible, given reasonable estimates of geothermal heat flux and regolith permeability. For pure water convection, the upper limit of the liquid zone would lie at some depth, but in the case of salt solutions, the boundary between liquid and frozen pore water could reach virtually to the surface. The principal drivers for hydrothermal circulation are regolith permeability, geothermal heat flux, surface temperature and salt composition. Both the Clifford and the Hanna-Phillips models of Martian regolith permeability predict sufficiently high permeabilities to sustain hydrothermal convection. Salts in solution will concentrate in upwelling plumes as the cold surface is approached. As water ice is excluded upon freezing, the remaining solution becomes a more concentrated brine, reaching its eutectic concentration before freezing. Numerical simulations considering several salts (NaCl, CaCl2, MgSO4), and a range of heat fluxes (20 - 100 mW/m2) covering the range of estimated present day heat flux (20 to 40 mW/m2) to moderately elevated conditions (60 to 100 mW/m2) such as might exist in the vicinity of volcanoes and craters, all indicate the same qualitative behavior. A completely liquid, convective regime occurs at depth, overlain by a partially frozen "mushy" layer (but still convecting despite the increased viscosity), overlain by a thin frozen layer at the surface. The thicknesses of these layers depend on the heat flux, surface temperature and the salt. As heat flux increases, the mushy region

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

    Energy Technology Data Exchange (ETDEWEB)

    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

  7. Impact of Water Recovery from Wastes on the Lunar Surface Mission Water Balance

    Science.gov (United States)

    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.

  8. The significant surface-water connectivity of "geographically isolated wetlands"

    Science.gov (United States)

    Calhoun, Aram J. K.; Mushet, David M.; Alexander, Laurie C.; DeKeyser, Edward S.; Fowler, Laurie; Lane, Charles R.; Lang, Megan W.; Rains, Mark C.; Richter, Stephen; Walls, Susan

    2017-01-01

    We evaluated the current literature, coupled with our collective research expertise, on surface-water connectivity of wetlands considered to be “geographically isolated” (sensu Tiner Wetlands 23:494–516, 2003a) to critically assess the scientific foundation of grouping wetlands based on the singular condition of being surrounded by uplands. The most recent research on wetlands considered to be “geographically isolated” shows the difficulties in grouping an ecological resource that does not reliably indicate lack of surface water connectivity in order to meet legal, regulatory, or scientific needs. Additionally, the practice of identifying “geographically isolated wetlands” based on distance from a stream can result in gross overestimates of the number of wetlands lacking ecologically important surface-water connections. Our findings do not support use of the overly simplistic label of “geographically isolated wetlands”. Wetlands surrounded by uplands vary in function and surface-water connections based on wetland landscape setting, context, climate, and geographic region and should be evaluated as such. We found that the “geographically isolated” grouping does not reflect our understanding of the hydrologic variability of these wetlands and hence does not benefit conservation of the Nation’s diverse wetland resources. Therefore, we strongly discourage use of categorizations that provide overly simplistic views of surface-water connectivity of wetlands fully embedded in upland landscapes.

  9. Operational Surface Water Detection and Monitoring Using Radarsat 2

    Directory of Open Access Journals (Sweden)

    Sandra Bolanos

    2016-03-01

    Full Text Available Traditional on-site methods for mapping and monitoring surface water extent are prohibitively expensive at a national scale within Canada. Despite successful cost-sharing programs between the provinces and the federal government, an extensive number of water features within the country remain unmonitored. Particularly difficult to monitor are the potholes in the Canadian Prairie region, most of which are ephemeral in nature and represent a discontinuous flow that influences water pathways, runoff response, flooding and local weather. Radarsat-2 and the Radarsat Constellation Mission (RCM offer unique capabilities to map the extent of water bodies at a national scale, including unmonitored sites, and leverage the current infrastructure of the Meteorological Service of Canada to monitor water information in remote regions. An analysis of the technical requirements of the Radarsat-2 beam mode, polarization and resolution is presented. A threshold-based procedure to map locations of non-vegetated water bodies after the ice break-up is used and complemented with a texture-based indicator to capture the most homogeneous water areas and automatically delineate their extents. Some strategies to cope with the radiometric artifacts of noise inherent to Synthetic Aperture Radar (SAR images are also discussed. Our results show that Radarsat-2 Fine mode can capture 88% of the total water area in a fully automated way. This will greatly improve current operational procedures for surface water monitoring information and impact a number of applications including weather forecasting, hydrological modeling, and drought/flood predictions.

  10. Adsorption of Speckled Sugar bean protein isolate at oil-water interface: Effect of ionic strength and pH.

    Science.gov (United States)

    Rahmati, Nazanin Fatemeh; Koocheki, Arash; Varidi, Mehdi; Kadkhodaee, Rassoul

    2017-02-01

    Speckled Sugar bean protein (0-4%) was used to stabilize sunflower oil in water emulsion (30% oil). To investigate the effect of other components on emulsion properties different salt concentrations (0-0.5M) and pH (3-7) were used. For this purpose, zeta potential, oil droplet size, adsorbed protein, non-adsorbed protein, viscosity, emulsifying capacity, emulsion stability and creaming rate were evaluated. Results showed that protein concentration was the most effective variable affected emulsions characteristics followed by protein-pH interaction as the second effective term. Salt somehow influenced emulsion properties but it had no negative effect on emulsifying capacity, emulsion stability or creaming rate. FTIR spectroscopy revealed that protein fractions with higher sheet secondary structure had better adsorption on oil droplets; while, fractions with helix subunit as the predominant secondary structure had the lowest adsorption capacity. At the end, emulsion properties were optimized based on the different independent and dependent variables. Results confirmed that Speckled Sugar bean protein was resistant to aggregation at high ionic strength. As a result, this protein could perform well as an emulsifier at different pH values. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Fabrication of superhydrophobic copper surface on various substrates for roll-off, self-cleaning, and water/oil separation.

    Science.gov (United States)

    Sasmal, Anup Kumar; Mondal, Chanchal; Sinha, Arun Kumar; Gauri, Samiran Sona; Pal, Jaya; Aditya, Teresa; Ganguly, Mainak; Dey, Satyahari; Pal, Tarasankar

    2014-12-24

    Superhydrophobic surfaces prevent percolation of water droplets and thus render roll-off, self-cleaning, corrosion protection, etc., which find day-to-day and industrial applications. In this work, we developed a facile, cost-effective, and free-standing method for direct fabrication of copper nanoparticles to engender superhydrophobicity for various flat and irregular surfaces such as glass, transparency sheet (plastic), cotton wool, textile, and silicon substrates. The fabrication of as-prepared superhydrophobic surfaces was accomplished using a simple chemical reduction of copper acetate by hydrazine hydrate at room temperature. The surface morphological studies demonstrate that the as-prepared surfaces are rough and display superhydrophobic character on wetting due to generation of air pockets (The Cassie-Baxter state). Because of the low adhesion of water droplets on the as-prepared surfaces, the surfaces exhibited not only high water contact angle (164 ± 2°, 5 μL droplets) but also superb roll-off and self-cleaning properties. Superhydrophobic copper nanoparticle coated glass surface uniquely withstands water (10 min), mild alkali (5 min in saturated aqueous NaHCO3 of pH ≈ 9), acids (10 s in dilute HNO3, H2SO4 of pH ≈ 5) and thiol (10 s in neat 1-octanethiol) at room temperature (25-35 °C). Again as-prepared surface (cotton wool) was also found to be very effective for water-kerosene separation due to its superhydrophobic and oleophilic character. Additionally, the superhydrophobic copper nanoparticle (deposited on glass surface) was found to exhibit antibacterial activity against both Gram-negative and Gram-positive bacteria.

  12. Studying surface water balance in Kurdistan province using GIS

    Directory of Open Access Journals (Sweden)

    Nader Fallah

    2016-06-01

    Full Text Available The study of water exchange in a region or area, which emphasizes the principle of conservation of matter in the water cycle, is called balance. Investigating their balance is the basis for managing the rivers’ water management, the results of which refer to the change rate in surface water supply and can efficiently be used in decision making and optimal use of water resources. The present study was carried out in order to investigate the surface water balance in Kurdistan province using GIS. In so doing, digital topographic maps, soil map of the area, and meteorological data retrieved from the regional stations were used to prepare layers of precipitation, evaporation and infiltration of rainwater into the soil. Discharge-arearegion comparative method was employed to measure the amount of runoff and base flow for each sub-basin in raster form saved per unit area which was subsequently overlapped based on balance equation, and the balance of the region was displayed in a graphical mode. The results indicated that more surface water is wasted in the southeast and central area of the province.

  13. Evaluation of water quality in surface water and shallow groundwater: a case study of a rare earth mining area in southern Jiangxi Province, China.

    Science.gov (United States)

    Hao, Xiuzhen; Wang, Dengjun; Wang, Peiran; Wang, Yuxia; Zhou, Dongmei

    2016-01-01

    This study was conducted to evaluate the quality of surface water and shallow groundwater near a rare earth mining area in southern Jiangxi Province, China. Water samples from paddy fields, ponds, streams, wells, and springs were collected and analyzed. The results showed that water bodies were characterized by low pH and high concentrations of total nitrogen (total N), ammonium nitrogen (NH4 (+)-N), manganese (Mn), and rare earth elements (REEs), which was likely due to residual chemicals in the soil after mining activity. A comparison with the surface water standard (State Environmental Protection Administration & General Administration of Quality Supervision, Inspection and Quarantine of China GB3838, 2002) and drinking water sanitary standard (Ministry of Health & National Standardization Management Committee of China GB5749, 2006) of China revealed that 88 % of pond and stream water samples investigated were unsuitable for agricultural use and aquaculture water supply, and 50 % of well and spring water samples were unsuitable for drinking water. Moreover, significant cerium (Ce) negative and heavy REEs enrichment was observed after the data were normalized to the Post-Archean Australian Shales (PAAS). Principal component analysis indicated that the mining activity had a more significant impact on local water quality than terrace field farming and poultry breeding activities. Moreover, greater risk of water pollution and adverse effects on local residents' health was observed with closer proximity to mining sites. Overall, these findings indicate that effective measures to prevent contamination of surrounding water bodies from the effects of mining activity are needed.

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

    Science.gov (United States)

    Chemin, Rémi; Caulliez, Guillemette

    2015-04-01

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

  15. Influence of building resolution on surface water inundation outputs

    Science.gov (United States)

    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

  16. Fluorescence measurements of serotonin-induced V-ATPase-dependent pH changes at the luminal surface in salivary glands of the blowfly Calliphora vicina.

    Science.gov (United States)

    Rein, Julia; Zimmermann, Bernhard; Hille, Carsten; Lang, Ingo; Walz, Bernd; Baumann, Otto

    2006-05-01

    Secretion in blowfly salivary glands is induced by the neurohormone serotonin and powered by a vacuolar-type H(+)-ATPase (V-ATPase) located in the apical membrane of the secretory cells. We have established a microfluorometric method for analysing pH changes at the luminal surface of the secretory epithelial cells by using the fluorescent dye 5-N-hexadecanoyl-aminofluorescein (HAF). After injection of HAF into the lumen of the tubular salivary gland, the fatty acyl chain of the dye molecule partitions into the outer leaflet of the plasma membrane and its pH-sensitive fluorescent moiety is exposed at the cell surface. Confocal imaging has confirmed that HAF distributes over the entire apical membrane of the secretory cells and remains restricted to this membrane domain. Ratiometric analysis of HAF fluorescence demonstrates that serotonin leads to a reversible dose-dependent acidification at the luminal surface. Inhibition by concanamycin A confirms that the serotonin-induced acidification at the luminal surface is due to H(+) transport across the apical membrane via V-ATPase. Measurements with pH-sensitive microelectrodes corroborate a serotonin-induced luminal acidification and demonstrate that luminal pH decreases by about 0.4 pH units at saturating serotonin concentrations. We conclude that ratiometric measurements of HAF fluorescence provide an elegant method for monitoring V-ATPase-dependent H(+) transport in the blowfly salivary gland in vivo and for analysing the spatiotemporal pattern of pH changes at the luminal surface.

  17. Infiltration of pesticides in surface water into nearby drinking water supply wells

    Science.gov (United States)

    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.

  18. Influence of Soil and Irrigation Water pH on the Availability of Phosphorus in Struvite Derived from Urine through a Greenhouse Pot Experiment.

    Science.gov (United States)

    Liu, Xiaoning; Tao, Yi; Wen, Guoqi; Kong, Fanxin; Zhang, Xihui; Hu, Zhengyi

    2016-05-04

    One greenhouse pot experiment was used to investigate the availability of phosphorus in struvite derived from urine affected by soil pH (cinnamon soil, pH 7.3; paddy soil, pH 5.3) and irrigation water (pH 6.0 and 7.5) with bird rapeseed (Brassica campestris L.). The biomass of applied struvite in paddy soil was significantly greater than that of applied calcium superphosphate. However, statistically significant differences were not observed in cinnamon soil. Soil-applied struvite had a higher Olsen P compared to soil-applied calcium superphosphate irrespective of soil type. The biomass of applied struvite and irrigation with pH 6.0 water was greater compared to that with irrigation with pH 7.3 water irrespective of soil type, accompanied with significantly higher leaf chlorophyll concentration. Therefore, struvite has the potential to be an effective P fertilizer, and acidic irrigation water has greater influence on the availability of phosphorus in struvite than does acidic soil.

  19. Water-, pH- and temperature relations of germination for the extreme xerophiles Xeromyces bisporus (FRR 0025), Aspergillus penicillioides (JH06THJ) and Eurotium halophilicum (FRR 2471)

    NARCIS (Netherlands)

    Stevenson, Andrew; Hamill, Philip G; Dijksterhuis, Jan; Hallsworth, John E

    2016-01-01

    Water activity, temperature and pH are determinants for biotic activity of cellular systems, biosphere function and, indeed, for all life processes. This study was carried out at high concentrations of glycerol, which concurrently reduces water activity and acts as a stress protectant, to

  20. Irrigation water acidification to neutralize alkalinity for nursery crop production: Substrate pH, electrical conductivity, and nutrient concentrations; and plant nutrition and growth

    Science.gov (United States)

    Liming agents (LA) in irrigation water, typically associated with carbonates and bicarbonates of calcium (Ca) and magnesium (Mg), contribute to water alkalinity. Repeated application of LA to container crops can cause media-solution pH to rise overtime, that uncorrected, can lead to a nutrient avail...

  1. Characterization of Alternaria and Penicillium species from similar substrata based on growth at different temperature, pH and water activity

    DEFF Research Database (Denmark)

    Andersen, Birgitte; Frisvad, Jens Christian

    2002-01-01

    Fifty-eight Alternaria isolates representing 10 species or species-groups and 66 Penicillium isolates representing 18 species were examined for their growth response to the combined effects of water activity, temperature and pH in an extended Central Composite Design. Growth responses were recorded...... incubated at two different temperatures were enough to get genus segregation and to some extent species segregation. The results also showed that water activity, temperature and pH interact strongly in their effect on growth rates and that the squared products (optima) of water activity, temperature and p...

  2. Return of naturally sourced Pb to Atlantic surface waters

    Science.gov (United States)

    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.

    2016-09-01

    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.

  3. Macroelements in the surface microlayer of water of urban ponds

    Directory of Open Access Journals (Sweden)

    Antonowicz Józef Piotr

    2016-03-01

    Full Text Available Analyses were conducted concerning the accumulation of four metals representing the group of macroelements, i.e. sodium, potassium, calcium and magnesium in two ponds located in the city of Słupsk. Water samples for chemical analyses were collected from the surface microlayer using a Garrett net. At the same time subsurface water samples were collected. Concentrations of metals were determined using a mass spectrometer. Generally, amounts of sodium, potassium, calcium and magnesium were similar in surface microlayer and subsurface water. Only in the case of potassium and calcium was low enrichment observed in the surface microlayer in one pond, while the greatest extent for magnesium enrichment was observed in the spring period.

  4. Occurrence of illicit drugs in surface waters in China.

    Science.gov (United States)

    Li, Kaiyang; Du, Peng; Xu, Zeqiong; Gao, Tingting; Li, Xiqing

    2016-06-01

    Illicit drugs have been recognized as a group of emerging contaminants. In this work, occurrence of common illicit drugs and their metabolites in Chinese surface waters was examined by collecting samples from 49 lakes and 4 major rivers across the country. Among the drugs examined, methamphetamine and ketamine were detected with highest frequencies and concentration levels, consistent with the fact that these are primary drugs of abuse in China. Detection frequencies and concentrations of other drugs were much lower than in European lakes and rivers reported in the literature. In most Chinese surface waters methamphetamine and ketamine were detected at concentrations of several ng L(-1) or less, but in some southern lakes and rivers, these two drugs were detected at much higher concentrations (up to several tens ng L(-1)). Greater occurrence of methamphetamine and ketamine in southern surface waters was attributed to greater abuse and more clandestine production of the two drugs in southern China.

  5. Wavefront modulation of water surface wave by a metasurface

    Institute of Scientific and Technical Information of China (English)

    孙海涛; 程营; 王敬时; 刘晓峻

    2015-01-01

    We design a planar metasurface to modulate the wavefront of a water surface wave (WSW) on a deep sub-wavelength scale. The metasurface is composed of an array of coiling-up-space units with specially designed parameters, and can take on the work of steering the wavefront when it is pierced into water. Like their acoustic counterparts, the modulation of WSW is ascribed to the gradient phase shift of the coiling-up-space units, which can be perfectly tuned by changing the coiling plate length and channel number inside the units. According to the generalized Snell’s law, negative refraction and‘driven’ surface mode of WSW are also demonstrated at certain incidences. Specially, the transmitted WSW could be efficiently guided out by linking a symmetrically-corrugated channel in‘driven’ surface mode. This work may have potential applications in water wave energy extraction and coastal protection.

  6. Effects of chlorine and other water quality parameters on the release of silver nanoparticles from a ceramic surface.

    Science.gov (United States)

    Bielefeldt, Angela R; Stewart, Michael W; Mansfield, Elisabeth; Scott Summers, R; Ryan, Joseph N

    2013-08-01

    A quartz crystal microbalance was used to determine the effects of different water quality parameters on the detachment of silver nanoparticles from surfaces representative of ceramic pot filters (CPFs). Silver nanoparticles stabilized with casein were used in the experiments. The average hydrodynamic diameter of the nanoparticles ranged from 20 nm to 100 nm over a pH range of 6.5-10.5. The isoelectric point was about 3.5 and the zeta potential was -45 mV from pH 4.5 to 9.5. The silver nanoparticles were deposited onto silica surfaces and a quartz crystal microbalance was used to monitor silver release from the surface. At environmentally relevant ranges of pH (4.8-9.3), ionic strength (0 and 150 mol/m(3) NaNO3 or 150 mol/m(3) Ca(NO3)2), and turbidity (0 and 51.5 NTU kaolin clay), the rates of silver release were similar. A high concentration of sodium chloride and bacteria (Echerichia coli in 10% tryptic soy broth) caused rapid silver release. Water containing sodium hypochlorite removed 85% of the silver from the silica surface within 3 h. The results suggest that contact between CPFs and prechlorinated water or bleach CPF cleaning should be avoided.

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

    Science.gov (United States)

    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.

  8. Zirconium fluoride glass - Surface crystals formed by reaction with water

    Science.gov (United States)

    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.

  9. Eutrophication management in surface waters using lanthanum modified bentonite

    DEFF Research Database (Denmark)

    Copetti, Diego; Finsterle, Karin; Marziali, Laura

    2016-01-01

    This paper reviews the scientific knowledge on the use of a lanthanum modified bentonite (LMB) to manage eutrophication in surface water. The LMB has been applied in around 200 environments worldwide and it has undergone extensive testing at laboratory, mesocosm, and whole lake scales. The availa......This paper reviews the scientific knowledge on the use of a lanthanum modified bentonite (LMB) to manage eutrophication in surface water. The LMB has been applied in around 200 environments worldwide and it has undergone extensive testing at laboratory, mesocosm, and whole lake scales...

  10. Evaluation of ATP measurements to detect microbial ingress by wastewater and surface water in drinking water

    DEFF Research Database (Denmark)

    Vang, Óluva Karin; Corfitzen, Charlotte B.; Smith, Christian

    2014-01-01

    in this respect. Compared to traditional microbiological methods, the ATP assay could detect wastewater and surface water in drinking water to a higher degree than total direct counts (TDCs), while both heterotrophic plate counts (HPC 22 °C and HPC 37 °C) and Colilert-18 (Escherichia coli and coliforms) were more......Fast and reliable methods are required for monitoring of microbial drinking water quality in order to protect public health. Adenosine triphosphate (ATP) was investigated as a potential real-time parameter for detecting microbial ingress in drinking water contaminated with wastewater or surface...

  11. Some Aspects of Surface Water Treatment Technology in Tirana Drinking Water Treatment Plant

    OpenAIRE

    , Tania Floqi; , Aleksandër Trajçe; , Daut Vezi

    2009-01-01

    Tirana’s Bovilla treatment plant was the Şrst of its kind for Albania, which treats surface water. The input water comes from the Bovilla artiŞcial lake, around which, the presence of villages induces pollution in the surface water and therefore affects the efŞciency of treatment plant and consequently the quality of drinking water. The treatment plant is a simple conventional system and includes pre-oxidation, coagulation, şocculation & sedimentation, fast Şltration, post-oxidation. ...

  12. Fluctuations of water near extended hydrophobic and hydrophilic surfaces

    OpenAIRE

    Patel, Amish J.; Chandler, David

    2009-01-01

    We use molecular dynamics simulations of the SPC-E model of liquid water to derive probability distributions for water density fluctuations in probe volumes of different shapes and sizes, both in the bulk as well as near hydrophobic and hydrophilic surfaces. To obtain our results, we introduce a biased sampling of coarse-grained densities, which in turn biases the actual solvent density. The technique is easily combined with molecular dynamics integration algorithms. Our principal result is t...

  13. Questa baseline and pre-mining ground-water quality investigation. 5. Well installation, water-level data, and surface- and ground-water geochemistry in the Straight Creek drainage basin, Red River Valley, New Mexico, 2001-03

    Science.gov (United States)

    Naus, Cheryl A.; McCleskey, R. Blaine; Nordstrom, D. Kirk; Donohoe, Lisa C.; Hunt, Andrew G.; Paillet, Frederick L.; Morin, Roger H.; Verplanck, Philip L.

    2005-01-01

    The U.S. Geological Survey, in cooperation with the New Mexico Environment Department, is investigating the pre-mining ground-water chemistry at the Molycorp molybdenum mine in the Red River Valley, northern New Mexico. The primary approach is to determine the processes controlling ground-water chemistry at an unmined, off-site, proximal analog. The Straight Creek drainage basin, chosen for this purpose, consists of the same quartz-sericite-pyrite altered andesitic and rhyolitic volcanic rock of Tertiary age as the mine site. The weathered and rugged volcanic bedrock surface is overlain by heterogeneous debris-flow deposits that interfinger with alluvial deposits near the confluence of Straight Creek and the Red River. Pyritized rock in the upper part of the drainage basin is the source of acid rock drainage (pH 2.8-3.3) that infiltrates debris-flow deposits containing acidic ground water (pH 3.0-4.0) and bedrock containing water of circumneutral pH values (5.6-7.7). Eleven observation wells were installed in the Straight Creek drainage basin. The wells were completed in debris-flow deposits, bedrock, and interfingering debris-flow and Red River alluvial deposits. Chemical analyses of ground water from these wells, combined with chemical analyses of surface water, water-level data, and lithologic and geophysical logs, provided information used to develop an understanding of the processes contributing to the chemistry of ground water in the Straight Creek drainage basin. Surface- and ground-water samples were routinely collected for determination of total major cations and selected trace metals; dissolved major cations, selected trace metals, and rare-earth elements; anions and alkalinity; and dissolved-iron species. Rare-earth elements were determined on selected samples only. Samples were collected for determination of dissolved organic carbon, mercury, sulfur isotopic composition (34S and 18O of sulfate), and water isotopic composition (2H and 18O) during

  14. Predicting Salmonella populations from biological, chemical, and physical indicators in Florida surface waters.

    Science.gov (United States)

    McEgan, Rachel; Mootian, Gabriel; Goodridge, Lawrence D; Schaffner, Donald W; Danyluk, Michelle D

    2013-07-01

    Coliforms, Escherichia coli, and various physicochemical water characteristics have been suggested as indicators of microbial water quality or index organisms for pathogen populations. The relationship between the presence and/or concentration of Salmonella and biological, physical, or chemical indicators in Central Florida surface water samples over 12 consecutive months was explored. Samples were taken monthly for 12 months from 18 locations throughout Central Florida (n = 202). Air and water temperature, pH, oxidation-reduction potential (ORP), turbidity, and conductivity were measured. Weather data were obtained from nearby weather stations. Aerobic plate counts and most probable numbers (MPN) for Salmonella, E. coli, and coliforms were performed. Weak linear relationships existed between biological indicators (E. coli/coliforms) and Salmonella levels (R(2) Salmonella levels (R(2) Salmonella levels. The lack of good correlations between biological indicators and Salmonella levels and between physicochemical indicators and Salmonella levels shows that the relationship between pathogens and indicators is complex. However, Escherichia coli provides a reasonable way to predict Salmonella levels in Central Florida surface water through logistic regression.

  15. Monitoring of endocrine disrupting chemicals in surface water

    CSIR Research Space (South Africa)

    Govender, S

    2008-06-01

    Full Text Available the surface. The chelated Pluronic-DMDDO ligand can be used for affinity purification of histidine tagged proteins. A regeneration formulation based on anionic SDS detergent desorbed pluronic modified polymeric membranes and the possibility of re... ingredients, household products and industrial chemicals. Surface waters are the main sink of said EDCs. Accurate EDC detection is usually via time consuming and costly ex situ LC-MS and GC-MS analysis. An important class of biosensors include those...

  16. Hydrodynamic boundary condition of water on hydrophobic surfaces.

    Science.gov (United States)

    Schaeffel, David; Yordanov, Stoyan; Schmelzeisen, Marcus; Yamamoto, Tetsuya; Kappl, Michael; Schmitz, Roman; Dünweg, Burkhard; Butt, Hans-Jürgen; Koynov, Kaloian

    2013-05-01

    By combining total internal reflection fluorescence cross-correlation spectroscopy with Brownian dynamics simulations, we were able to measure the hydrodynamic boundary condition of water flowing over a smooth solid surface with exceptional accuracy. We analyzed the flow of aqueous electrolytes over glass coated with a layer of poly(dimethylsiloxane) (advancing contact angle Θ = 108°) or perfluorosilane (Θ = 113°). Within an error of better than 10 nm the slip length was indistinguishable from zero on all surfaces.

  17. Effect of α-lactalbumin and β-lactoglobulin on the oxidative stability of 10% fish oil-in-water emulsions depends on pH

    DEFF Research Database (Denmark)

    Horn, Anna Frisenfeldt; Wulff, Tune; Nielsen, Nina Skall

    2013-01-01

    The objective of this study was to investigate the influence of pH on lipid oxidation and protein partitioning in 10% fish oil-in-water emulsions prepared with different whey protein isolates with varying ratios of α-lactalbumin and β-lactoglobulin. Results showed that an increase in pH increased...... lipid oxidation irrespective of the emulsifier used. At pH 4, lipid oxidation was not affected by the type of whey protein emulsifier used or the partitioning of proteins between the interface and the water phase. However, at pH 7 the emulsifier with the highest concentration of β......-lactoglobulin protected more effectively against oxidation during emulsion production, whereas the emulsions with the highest concentration of α-lactalbumin were most stable to oxidation during storage. These differences were explained by differences in the pressure and adsorption induced unfolding of the individual...

  18. Nanofiltration in Transforming Surface Water into Healthy Water: Comparison with Reverse Osmosis

    Directory of Open Access Journals (Sweden)

    L. D. Naidu

    2015-01-01

    Full Text Available The natural surface water, especially available through rivers, is the main source of healthy water for the living beings throughout the world from ancient days as it consists of all essential minerals. With the advent of industrialization, gradually even the most prominent rivers have been polluted in all parts of the world. Although there are lots of technologies, nanofiltration (NF has been chosen to transform river water into healthy water due to its unique advantages of retaining optimum TDS (with essential minerals required for human body, consuming of lower energy, and no usage of any chemicals. The prominent parameters of surface water and macro/microminerals of treated water have been analyzed. It is shown that NF is better in producing healthy water with high flux by consuming low energy.

  19. Spatial and temporal variability of surface water pollution in the Mekong Delta, Vietnam.

    Science.gov (United States)

    Wilbers, Gert-Jan; Becker, Mathias; Nga, La Thi; Sebesvari, Zita; Renaud, Fabrice G

    2014-07-01

    Surface water pollution in the Vietnamese Mekong Delta (MD) could threaten human, animal and ecosystem health given the fact that this water source is intensively used for drinking, irrigation and domestic services. We therefore determined the levels of pollution by organic pollutants, salts, metals and microbial indicators by (bi)monthly monitoring of canals between November 2011 and July 2012 at 32 sampling locations, representing fresh and saline/brackish environments. The results were compared with national water quality guidelines, between the studied regions and with water quality data from main waterways. Key factors explaining the observed levels of pollution in surface water were identified through principal component analysis (PCA). Temporal variations due to tidal regime and seasonality were also assessed. Based on regression models, the spatial variability of five water quality parameters was visualized using GIS based maps. Results indicate that pH (max. 8.6), turbidity (max. 461 FTU), maximum concentrations of ammonium (14.7 mg L(-1)), arsenic (44.1 μg L(-1)), barium (157.5 μg L(-1)), chromium (84.7 μg L(-1)), mercury (45.5 μg L(-1)), manganese (1659.7 μg L(-1)), aluminum (14.5 mg L(-1)), iron (17.0 mg L(-1)) and the number of Escherichia coli (87,000 CFU 100 mL(-1)) and total coliforms (2,500,000 CFU 100 mL(-1)) in canals exceed the thresholds set by Vietnamese quality guidelines for drinking and domestic purposes. The PCA showed that i) urbanization; ii) metal leaching from soils; iii) aquaculture; and iv) tidal regime explain 85% of the variance of surface water quality attributes. Significant differences in water quality were found due to daily tidal regime and as a result of seasonality. Surface water quality maps for dissolved oxygen, ammonium, ortho-phosphate, manganese and total coliforms were developed to highlight hot-spot areas of pollution. The results of this study can assist policy makers in developing water management strategies

  20. Surface Tension of Ab Initio Liquid Water at the Water-Air Interface

    CERN Document Server

    Nagata, Yuki; Bonn, Mischa; Kühne, Thomas D

    2016-01-01

    We report calculations of the surface tension of the water-air interface using ab initio molecular dynamics (AIMD) simulations. We investigate the simulation cell size dependence of the surface tension of water from force field molecular dynamics (MD) simulations, which show that the calculated surface tension increases with increasing simulation cell size, thereby illustrating that a correction for finite size effects is required for the small system used in the AIMD simulation. The AIMD simulations reveal that the double-{\\xi} basis set overestimates the experimentally measured surface tension due to the Pulay stress, while the triple and quadruple-{\\xi} basis sets give similar results. We further demonstrate that the van der Waals corrections critically affect the surface tension. AIMD simulations without the van der Waals correction substantially underestimate the surface tension, while van der Waals correction with the Grimme's D2 technique results in the value for the surface tension that is too high. T...

  1. Groundwater - surface water interactions in the Ayeyarwady river delta, Myanmar

    Science.gov (United States)

    Miyaoka, K.; Haruyama, S.; Kuzuha, Y.; Kay, T.

    2012-12-01

    Groundwater is widely used as a water resource in the Ayeyarwady River delta. But, Groundwater has some chemical problem in part of the area. To use safety groundwater for health, it is important to make clear the actual conditions of physical and chemical characteristics of groundwater in this delta. Besides, Ayeyarwady River delta has remarkable wet and dry season. Surface water - groundwater interaction is also different in each season, and it is concerned that physical and chemical characteristics of groundwater is affected by the flood and high waves through cyclone or monsoon. So, it is necessary to research a good aquifer distribution for sustainable groundwater resource supply. The purposes of this study are evaluate to seasonal change of groundwater - surface water interactions, and to investigate the more safety aquifer to reduce the healthy risk. Water samples are collected at 49 measurement points of river and groundwater, and are analyzed dissolved major ions and oxygen and hydro-stable isotope compositions. There are some groundwater flow systems and these water qualities are different in each depth. These showed that physical and chemical characteristics of groundwater are closely related to climatological, geomorphogical, geological and land use conditions. At the upper Alluvium, groundwater quality changes to lower concentration in wet season, so Ayeyarwady River water is main recharge water at this layer in the wet season. Besides, in the dry season, water quality is high concentration by artificial activities. Shallower groundwater is affected by land surface conditions such as the river water and land use in this layer. At lower Alluvium, Arakan and Pegu mountains are main recharge area of good water quality aquifers. Oxygen18 value showed a little affected by river water infiltration in the wet season, but keep stable good water quality through the both seasons. In the wet season, the same groundwater exists and water quality changes through

  2. Desenvolvimento de um sistema para o controle do pH da água para microirrigação Development of a system for control of water pH for microirrigation

    Directory of Open Access Journals (Sweden)

    Marinaldo F Pinto

    2011-02-01

    Full Text Available O objetivo deste trabalho foi desenvolver um sistema eletrônico de controle do pH da água para microirrigação. O trabalho foi realizado no Laboratório de Hidráulica do Departamento de Engenharia de Biossistemas (LEB da Escola Superior de Agricultura "Luiz de Queiroz" (ESALQ/USP. O sistema de controle consta de um sensor de pH, um circuito eletrônico programado para manter o pH da água em 5,5 e um dispositivo de injeção de ácido controlado por uma válvula solenóide comandada por pulsos elétricos enviados pelo circuito eletrônico. O sistema foi testado em águas de diferentes valores iniciais de pH (variando de 6,2 a 9,2 sob vazão constante (264 L h-1 e variável, sendo efetuada a medição do pH imediatamente à jusante do sistema e ao longo da linha lateral, nos pontos situados a 1, 14, 29 e 44 m do início e em diferentes intervalos de tempo a partir do início dos ensaios. Os resultados obtidos comprovam a eficiência do sistema para manter o pH da água na faixa desejada, tanto para a condição de vazão constante quanto para a variável. Não foram verificadas variações temporais nem espaciais significativas na linha lateral de irrigação.The aim of this work was to develop an electronic system for control of water pH in microirrigation. The study was accomplished in the Hydraulics Laboratory of Biossystems Engineering Department, Escola Superior de Agricultura "Luiz de Queiroz" (ESALQ/USP. The water pH control system has a device for acid injection controlled by a solenoid valve. This valve is switched on by electric pulses from a microcontroller. The system was evaluated for different water pH values (ranging from 6.2 to 9.2 under constant (264 L h-1 and variable flow. The pH was measured immediately on system downstream, and along the lateral line at 1, 14, 29, and 44 m from the lateral inlet, tests were also accomplished for different intervals of time. The obtained results proved the efficiency of the system on

  3. Molecular dynamics simulation of the effect of pH on the adsorption of rhodamine laser dyes on TiO2 hydroxylated surfaces

    OpenAIRE

    Hamad, Said; Sanchez Valencia, Juan Ramon; Barranco, Angel; Mejias, Jose Antonio; González-Elipe, Agustin R

    2009-01-01

    Abstract We have carried out a study of the adsorption, on the (101) surface of anatase TiO2, of two industrially relevant rhodamines molecules (rhodamine 6G and rhodamine 800) employing Molecular Dynamics. These theoretical studies have shown that Rhodamine 6G must adsorb on surfaces under basic conditions. Moreover, the adsorption of this molecule shows a strong dependence upon the pH of the system, i.e. under neutral conditions the adsorption energy is quite smaller, and under ...

  4. In situ observation of biotite (001) surface dissolution at pH 1 and 9.5 by advanced optical microscopy

    OpenAIRE

    Chiara Cappelli; Daniel Lamarca-Irisarri; Jordi Camas; F. Javier Huertas; van Driessche, Alexander E.S.

    2015-01-01

    Laser confocal differential interference contrast microscopy (LCM-DIM) allows for the study of the reactivity of surface minerals with slow dissolution rates (e.g., phyllosilicates). With this technique, it is possible to carry out in situ inspection of the reacting surface in a broad range of pH, ionic strength and temperature providing useful information to help unravel the dissolution mechanisms of phyllosilicates. In this work, LCM-DIM was used to study the mechanisms controlling the biot...

  5. Evaluation of the residual liquid junction potential contribution to the uncertainty in pH measurement: a case study on low ionic strength natural waters.

    Science.gov (United States)

    Kadis, Rouvim; Leito, Ivo

    2010-04-01

    The residual liquid junction potential (RLJP) needs to be accounted for in pH uncertainty estimation. Attempts to do this and the currently available methods for evaluating the RLJP are critically discussed and their weak sides are pointed out. In this work an empirical approach to the problem is proposed. It is based on the use of the RLJP bias estimated on a variety of measurement conditions for a specific class of analytical objects essentially differing in ionic strength from the pH calibration buffers. The data from five independent studies, including interlaboratory comparisons, on pH measurement in low ionic strength waters were used to find the overall bias observed in the 10(-4) mol dm(-3) strong acid solution. The procedure includes quantifying the uncertainty of bias values from separate studies by combination of the relevant uncertainty components and testing the consistency of the data. The weighted mean bias in pH was found to be 0.043+/-0.007 (k=2). With this estimate, the pH measurement uncertainties calculated according to the previously suggested procedure (I. Leito, L. Strauss, E. Koort, V. Pihl, Accredit. Qual. Assur. 7 (2002) 242-249.) can be enlarged to take the uncorrected bias into account. The resulting uncertainties on the level of 0.10-0.14 (k=2) are obtained in this way for pH measurement in water and poorly buffered aqueous solutions in the range of pH 7.5-3.5.

  6. Distribution of tritium in precipitation and surface water in California

    Science.gov (United States)

    Harms, Patrick A.; Visser, Ate; Moran, Jean E.; Esser, Brad K.

    2016-03-01

    The tritium concentration in the surface hydrosphere throughout California was characterized to examine the reasons for spatial variability and to enhance the applicability of tritium in hydrological investigations. Eighteen precipitation samples were analyzed and 148 samples were collected from surface waters across California in the Summer and Fall of 2013, with repeat samples from some locations collected in Winter and Spring of 2014 to examine seasonal variation. The concentration of tritium in present day precipitation varied from 4.0 pCi/L near the California coast to 17.8 pCi/L in the Sierra Nevada Mountains. Concentrations in precipitation increase in spring due to the 'Spring Leak' phenomenon. The average coastal concentration (6.3 ± 1.2 pCi/L) in precipitation matches estimated pre-nuclear levels. Surface water samples show a trend of increasing tritium with inland distance. Superimposed on that trend, elevated tritium concentrations are found in the San Francisco Bay area compared to other coastal areas, resulting from municipal water imported from inland mountain sources and local anthropogenic sources. Tritium concentrations in most surface waters decreased between Summer/Fall 2013 and Winter/Spring 2014 likely due to an increased groundwater signal as a result of drought conditions in 2014. A relationship between tritium and electrical conductivity in surface water was found to be indicative of water provenance and anthropogenic influences such as agricultural runoff. Despite low initial concentrations in precipitation, tritium continues to be a valuable tracer in a post nuclear bomb pulse world.

  7. Water and Carbon Dioxide Adsorption at Olivine Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    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. Surface Water Data at Los Alamos National Laboratory 1998 Water Year

    Energy Technology Data Exchange (ETDEWEB)

    D. A. Shaull; M. R. Alexander; R. P. Reynolds; C. T. McLean; R. P. Romero

    1999-02-01

    The principal investigators collected and computed surface water discharge data from 19 stream-gaging stations that cover most of Los Alamos National Laboratory. Also included are discharge data from three springs that flow into Caiion de Vane.

  9. Scaling up ecohydrological processes: role of surface water flow in water-limited landscapes

    CSIR Research Space (South Africa)

    Popp, A

    2009-11-01

    Full Text Available microscale processes like ecohydrological feedback mechanisms and spatial exchange like surface water flow, the authors derive transition probabilities from a fine-scale simulation model. They applied two versions of the landscape model, one that includes...

  10. Theoretical Study of Sodium-Water Surface Reaction Mechanism

    Science.gov (United States)

    Kikuchi, Shin; Kurihara, Akikazu; Ohshima, Hiroyuki; Hashimoto, Kenro

    Computational study of the sodium-water reaction at the gas (water) - liquid (sodium) interface has been carried out using the ab initio (first-principle) method. A possible reaction channel has been identified for the stepwise OH bond dissociations of a single water molecule. The energetics including the binding energy of a water molecule on the sodium surface, the activation energies of the bond cleavages, and the reaction energies, have been evaluated, and the rate constants of the first and second OH bond-breakings have been compared. It was found that the estimated rate constant of the former was much larger than the latter. The results are the basis for constructing the chemical reaction model used in a multi-dimensional sodium-water reaction code, SERAPHIM, being developed by Japan Atomic Energy Agency (JAEA) toward the safety assessment of the steam generator (SG) in a sodium-cooled fast reactor (SFR).

  11. The effect of water pH on the incubation and larviculture of curimbatá Prochilodus lineatus (Valenciennes, 1837 (Characiformes: Prochilodontidae

    Directory of Open Access Journals (Sweden)

    David Augusto Reynalte-Tataje

    Full Text Available Different pH levels of water in the incubation and larviculture of 'curimbatá' (Prochilodus lineatus were tested to evaluate the effect of this variable on the survival and development of eggs and larvae. During incubation, pH of 5.0, 6.0, 7.0, 8.0, and 8.5 was tested. To observe the effects of pH on larvae with different hatchery histories, the following experimental design was utilised (pH incubation - pH larviculture: L 6-6; L 6-7; L 7-6; L 7-7; L 7-8; L 8-7; L 8-8; L 8.5-7, and L 8.5-8.5. At pH 5.0 and four hours after incubation, an almost total mortality of incubated eggs was seen. Eggs incubated at pH 6.0 to 8.5 had similar fertilization and survival rates at the end of incubation, although eggs and larvae incubated at pH 6.0 had a smaller diameter and total length than larvae incubated at neutral and alkaline pH. During larviculture, it was observed the highest post-larvae survival rates with incubation at pH values of 7.0 (93 ± 7% and the largest post-larvae lengths from the L 8.5-7 treatment (9.29 ± 0.8 mm. It can be concluded that hatchery and larviculture pH directly affects the initial developmental stages of P. lineatus.

  12. Solid-phase microextraction for determination of anilino-pyrimidine, dimethylcarbamate and thiadiazine pesticides in irrigation project surface water

    OpenAIRE

    Silva Filho,Clóvis F; Emídio,Elissandro S.; Dórea,Haroldo S.

    2011-01-01

    The objective of this work was to develop a solid-phase microextraction (SPME) technique for the determination of residues of the pyrimethanil, pirimicarb and buprofezin pesticides in surface waters from irrigated areas, with analysis by gas chromatography-mass spectrometry (GC-MS). The optimized method used a 100 µm polydimethylsiloxane (PDMS) fiber, agitation speed of the sample of 900 rpm and pH 7.0. Extraction and desorption times were 30 and 7 min, respectively. Linearity was achieved in...

  13. Hydrogeochemical features of surface water and groundwater contaminated with acid mine drainage (AMD) in coal mining areas: a case study in southern Brazil.

    Science.gov (United States)

    Galhardi, Juliana Aparecida; Bonotto, Daniel Marcos

    2016-09-01

    Effects of acid mine drainage (AMD) were investigated in surface waters (Laranjinha River and Ribeirão das Pedras stream) and groundwaters from a coal mining area sampled in two different seasons at Figueira city, Paraná State, Brazil. The spatial data distribution indicated that the acid effluents favor the chemical elements leaching and transport from the tailings pile into the superficial water bodies or aquifers, modifying their quality. The acid groundwaters in both sampling periods (dry: pH 2.94-6.04; rainy: pH 3.25-6.63) were probably due to the AMD generation and infiltration, after the oxidation of sulfide minerals. Such acid effluents cause an increase of the solubilization rate of metals, mainly iron and aluminum, contributing to both groundwater and surface water contamination. Sulfate in high levels is a result of waters' pollution due to AMD. In some cases, high sulfate and low iron contents, associated with less acidic pH values, could indicate that AMD, previously generated, is nowadays being neutralized. The chemistry of the waters affected by AMD is controlled by the pH, sulfide minerals' oxidation, oxygen, iron content, and microbial activity. It is also influenced by seasonal variations that allow the occurrence of dissolution processes and the concentration of some chemical elements. Under the perspective of the waters' quality evaluation, the parameters such as conductivity, dissolved sodium, and sulfate concentrations acted as AMD indicators of groundwaters and surface waters affected by acid effluents.

  14. DBP formation in hot and cold water across a simulated distribution system: effect of incubation time, heating time, pH, chlorine dose, and incubation temperature.

    Science.gov (United States)

    Liu, Boning; Reckhow, David A

    2013-10-15

    This paper demonstrates that disinfection byproducts (DBP) concentration profiles in heated water were quite different from the DBP concentrations in the cold tap water. Chloroform concentrations in the heated water remained constant or even decreased slightly with increasing distribution system water age. The amount of dichloroacetic acid (DCAA) was much higher in the heated water than in the cold water; however, the maximum levels in heated water with different distribution system water ages did not differ substantially. The levels of trichloroacetic acid (TCAA) in the heated water were similar to the TCAA levels in the tap water, and a slight reduction was observed after the tap water was heated for 24 h. Regardless of water age, significant reductions of nonregulated DBPs were observed after the tap water was heated for 24 h. For tap water with lower water ages, there were significant increases in dichloroacetonitrile (DCAN), chloropicrin (CP), and 1,1-dichloropropane (1,1-DCP) after a short period of heating. Heating of the tap water with low pH led to a more significant increase of chloroform and a more significant short-term increase of DCAN. High pH accelerated the loss of the nonregulated DBPs in the heated water. The results indicated that as the chlorine doses increased, levels of chloroform and DCAA in the heated water increased significantly. However, for TCAA, the thermally induced increase in concentration was only notable for the chlorinated water with very high chlorine dose. Finally, heating may lead to higher DBP concentrations in chlorinated water with lower distribution system temperatures.

  15. IMPROVING CYANOBACTERIA AND CYANOTOXIN MONITORING IN SURFACE WATERS FOR DRINKING WATER SUPPLY

    Directory of Open Access Journals (Sweden)

    Jing Li

    2017-06-01

    Full Text Available Cyanobacteria in fresh water can cause serious threats to drinking water supplies. Managing cyanobacterial blooms particularly at small drinking water treatment plants is challenging. Because large amount of cyanobacteria may cause clogging in the treatment process and various cyanotoxins are hard to remove, while they may cause severe health problems. There is lack of instructions of what cyanobacteria/toxin amount should trigger what kind of actions for drinking water management except for Microcystins. This demands a Cyanobacteria Management Tool (CMT to help regulators/operators to improve cyanobacteria/cyanotoxin monitoring in surface waters for drinking water supply. This project proposes a CMT tool, including selecting proper indicators for quick cyanobacteria monitoring and verifying quick analysis methods for cyanobacteria and cyanotoxin. This tool is suggested for raw water management regarding cyanobacteria monitoring in lakes, especially in boreal forest climate. In addition, it applies to regions that apply international WHO standards for water management. In Swedish context, drinking water producers which use raw water from lakes that experience cyanobacterial blooms, need to create a monitoring routine for cyanobacteria/cyanotoxin and to monitor beyond such as Anatoxins, Cylindrospermopsins and Saxitoxins. Using the proposed CMT tool will increase water safety at surface water treatment plants substantially by introducing three alerting points for actions. CMT design for each local condition should integrate adaptive monitoring program.

  16. Thin Water and Ice Films at Mineral Surfaces

    Science.gov (United States)

    Yeşilbaş, Merve; Boily, Jean-François

    2016-04-01

    Mineral-water and ice interactions play important roles in atmospheric cloud formation. They also affect soil biogeochemistry as well as outer-space processes. In this study, thin water and ice films formed on minerals of varied bulk and surface structure, shape, size and surface roughness were probed by Fourier Transform Infrared Spectroscopy (FTIR) and by Dynamic Vapor Adsorption (DVA). Measurements on several types of iron (oxyhydr)oxides, phyllosilicates, orthosilicates, tectosilicates as well as Arizona Test Dust (ATD) and Icelandic volcanic ash constrained our understanding of the molecular-level nature of mineral surface-water and ice interactions. DVA experiments showed that particle size is the key feature controlling water loadings at 25 ° C. Under this condition, nano-sized particles stabilized the equivalence of no more than ˜6 monolayers of water at the near saturation of water vapor while sub-micron sized particles stabilized several thousand layers. This result can be explained by the greater ability of larger sized particles at driving water condensation reactions. Cryogenic FTIR measurements at -10 and -50 ° C revealed that most minerals acquired the thin ice films with similar hydrogen bonding environments as those formed at room temperature.[1,2] These thin ice films have weaker hydrogen bond environments than hexagonal ice (νOH ≈ 3130 cm-1), a result seen by FTIR through predominant O-H stretching modes at νOH ≈ 3408-3425 cm-1. The water bending region (˜1630 cm-1) also reveals that most thin ice films are rather supercooled forms of water. Only the materials with greatest levels of heterogeneity, namely ATD and volcanic ash, stabilized solid forms of water reminiscent to hexagonal ice. This work thus constrains further our understanding of how interfacial ice is stabilized at mineral surfaces, and opens possibilities for future studies focused on atmospheric gas uptake on mineral- water and ice admixtures. [1] Song, X. and Boily, J

  17. Uranium in US surface, ground, and domestic waters. Volume 2

    Energy Technology Data Exchange (ETDEWEB)

    Drury, J.S.; Reynolds, S.; Owen, P.T.; Ross, R.H.; Ensminger, J.T.

    1981-04-01

    The report Uranium in US Surface, Ground, and Domestic Waters comprises four volumes. Volumes 2, 3, and 4 contain data characterizing the location, sampling date, type, use, and uranium conentrations of 89,994 individual samples presented in tabular form. The tabular data in volumes 2, 3, and 4 are summarized in volume 1 in narrative form and with maps and histograms.

  18. Surface water and groundwater interaction on a hill island

    DEFF Research Database (Denmark)

    Frederiksen, Rasmus Rumph; Rasmussen, Keld Rømer; Christensen, Steen

    – the hill islands – is relatively unknown. This study aims at providing new information about the rainfall-runoff processes in hill island landscapes where surface water and groundwater interaction is expected to have a dominant role and hill-slope processes not. Through stream flow measurements, field...

  19. The interaction of water and hydrogen with nickel surfaces

    NARCIS (Netherlands)

    Shan, Junjun

    2009-01-01

    As nickel and platinum are in the same group of the periodic table, the Ni(111) and Pt(111) surfaces may be expected to show similar interaction with water and hydrogen. However in this thesis, we show these interactions for Ni(111) are quite different from those of Pt(111). Moreover, our results

  20. Observation of water condensate on hydrophobic micro textured surfaces

    Science.gov (United States)

    Kim, Ki Wook; Do, Sang Cheol; Ko, Jong Soo; Jeong, Ji Hwan

    2013-07-01

    We visually observed that a dropwise condensation occurred initially and later changed into a filmwise condensation on hydrophobic textured surface at atmosphere pressure condition. It was observed that the condensate nucleated on the pillar side walls of the micro structure and the bottom wall adhered to the walls and would not be lifted to form a spherical water droplet using environmental scanning electron microscope.

  1. Zearalenone occurrence in surface waters in central Illinois, USA

    Science.gov (United States)

    Zearalenone (ZEN) is an estrogenic secondary metabolite produced by certain fungi that commonly infest important cereal crops, such as corn and wheat. The ability of ZEN to move from contaminated crops to surface waters has been demonstrated previously. This article reports the development of a meth...

  2. Surface water risk assessment of pesticides in Ethiopia

    NARCIS (Netherlands)

    Teklu, B.M.; Adriaanse, P.I.; Horst, ter M.M.S.; Deneer, J.W.; Brink, van den P.J.

    2015-01-01

    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

  3. Riparian shrub buffers reduce surface water pollutant loads

    Science.gov (United States)

    W. A. Geyer; C. Barden; K. Mankin; D. Devlin

    2003-01-01

    Surface water resources in Kansas often contain concentrations of pesticides, nutrients, and sediments that are of concern to local citizens. The United States Geological Survey reported in 1999 that 97 percent of streams and 82 percent of lakes in Kansas would not fully support all uses as designated by state statutes (U.S. Geological Survey 1999). Bacteria and...

  4. Modelling the effects of surface water flood pulses on groundwater

    NARCIS (Netherlands)

    Schot, P.P.; Wassen, M.J.

    2010-01-01

    Flood pulses in wetlands steer ecosystem development directly through surface water processes and indirectly through the effects of the flood pulse on groundwater. Direct effects on ecosystems are exerted by e.g. inundation and deposition of sediments containing nutrients. Indirect effects include t

  5. The interaction of water and hydrogen with nickel surfaces

    NARCIS (Netherlands)

    Shan, Junjun

    2009-01-01

    As nickel and platinum are in the same group of the periodic table, the Ni(111) and Pt(111) surfaces may be expected to show similar interaction with water and hydrogen. However in this thesis, we show these interactions for Ni(111) are quite different from those of Pt(111). Moreover, our results sh

  6. Surface water risk assessment of pesticides in Ethiopia

    NARCIS (Netherlands)

    Teklu, B.M.; Adriaanse, P.I.; Horst, ter M.M.S.; Deneer, J.W.; Brink, van den P.J.

    2015-01-01

    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

  7. An Experimental Study of Planing Surfaces Operating in Shallow Water

    Science.gov (United States)

    1976-09-01

    D C APPROVED FOR PUBLIC RELEASE; (7 DISTRIBUTION UNLIMITED 22 1918 PT CLAIME Ar-Th -L’A THI S DOUETI 7E QUALITLY . AVAIILABIJaTECP FURNSR DTO DTIC...Aerodynamic tares were determined by towing the model just above the water surface at various trims and speeds. Only the drag was greatly affected by air

  8. CONTROLLING STORM WATER RUNOFF WITH TRADABLE CREDITS FOR IMPERVIOUS SURFACES

    Science.gov (United States)

    Storm water flow off impervious surface in a watershed can lead to stream degradation, habitat alteration, low base flows and toxic leading. We show that a properly designed tradable runoff credit (TRC) system creates economic incentives for landowners to employ best management p...

  9. Quality of surface-water supplies in the Triangle area of North Carolina, water year 2008

    Science.gov (United States)

    Giorgino, M.J.; Rasmussen, R.B.; Pfeifle, C.A.

    2012-01-01

    Surface-water supplies are important sources of drinking water for residents in the Triangle area of North Carolina, which is located within the upper Cape Fear and Neuse River Basins. Since 1988, the U.S. Geological Survey and a consortium of governments have tracked water-quality conditions and trends in several of the area's water-supply lakes and streams. This report summarizes data collected through this cooperative effort, known as the Triangle Area Water Supply Monitoring Project, during October 2007 through September