Evaporation of tiny water aggregation on solid surfaces with different wetting properties.

PubMed

Wang, Shen; Tu, Yusong; Wan, Rongzheng; Fang, Haiping

2012-11-29

The evaporation of a tiny amount of water on the solid surface with different wettabilities has been studied by molecular dynamics simulations. From nonequilibrium MD simulations, we found that, as the surface changed from hydrophobic to hydrophilic, the evaporation speed did not show a monotonic decrease as intuitively expected, but increased first, and then decreased after it reached a maximum value. The analysis of the simulation trajectory and calculation of the surface water interaction illustrate that the competition between the number of water molecules on the water-gas surface from where the water molecules can evaporate and the potential barrier to prevent those water molecules from evaporating results in the unexpected behavior of the evaporation. This finding is helpful in understanding the evaporation on biological surfaces, designing artificial surfaces of ultrafast water evaporating, or preserving water in soil.

Fully-Integrated Simulation of Conjunctive Use from Field to Basin Scales: Development of a Surface Water Operations Module for MODFLOW-OWHM

NASA Astrophysics Data System (ADS)

Ferguson, I. M.; Boyce, S. E.; Hanson, R. T.; Llewellyn, D.

2014-12-01

It is well established that groundwater pumping affects surface-water availability by intercepting groundwater that would otherwise discharge to streams and/or by increasing seepage from surface-water channels. Conversely, surface-water management operations effect groundwater availability by altering the timing, location, and quantity of groundwater recharge and demand. Successful conjunctive use may require analysis with an integrated approach that accounts for the many interactions and feedbacks between surface-water and groundwater availability and their joint management. In order to improve simulation and analysis of conjunctive use, Bureau of Reclamation and USGS are collaborating to develop a surface-water operations module within MODFLOW One Water Hydrologic Flow Model (MF-OWHM), a new version of the USGS Modular Groundwater Flow Model (MODFLOW). Here we describe the development and application of the surface-water operations module. We provide an overview of the conceptual approach used to simulate surface-water operations—including surface-water storage, allocation, release, diversion, and delivery on monthly to seasonal time frames—in a fully-integrated manner. We then present results from a recent case study analysis of the Rio Grande Project, a large-scale irrigation project located in New Mexico and Texas, under varying surface-water operations criteria and climate conditions. Case study results demonstrate the importance of integrated hydrologic simulation of surface water and groundwater operations in analysis and management of conjunctive-use systems.

Emission of dimers from a free surface of heated water

NASA Astrophysics Data System (ADS)

Bochkarev, A. A.; Polyakova, V. I.

2014-09-01

The emission rate of water dimers from a free surface and a wetted solid surface in various cases was calculated by a simplified Monte Carlo method with the use of the binding energy of water molecules. The binding energy of water molecules obtained numerically assuming equilibrium between the free surface of water and vapor in the temperature range of 298-438 K corresponds to the coordination number for liquid water equal to 4.956 and is close to the reference value. The calculation results show that as the water temperature increases, the free surface of water and the wetted solid surface become sources of free water dimers. At a temperature of 438 K, the proportion of dimers in the total flow of water molecules on its surface reaches 1%. It is found that in the film boiling mode, the emission rate of dimers decreases with decreasing saturation vapor. Two mechanisms of the emission are described.

Effectiveness of disinfectant wipes for decontamination of bacteria on patients' environmental and medical equipment surfaces at Siriraj Hospital.

PubMed

Seenama, Chakkraphong; Tachasirinugune, Peenithi; Jintanothaitavorn, Duangporn; Kachintorn, Kanchana; Thamlikitkul, Visanu

2013-02-01

To determine the effectiveness of Virusolve+ disinfectant wipes and PAL disinfectant wipes for decontamination of inoculated bacteria on patients' environmental and medical equipment surfaces at Siriraj Hospital. Tryptic soy broths containing MRSA and XDR A. baumannii were painted onto the surfaces of patient's stainless steel bed rail, patient's fiber footboard, control panel of infusion pump machine and control panel of respirator. The contaminated surfaces were cleaned by either tap water, tap water containing detergent, Virusolve+ disinfectant wipes or PAL disinfectant wipes. The surfaces without any cleaning procedures served as the control surface. The contaminated surfaces cleaned with the aforementioned procedures and control surfaces were swabbed with cotton swabs. The swabs were streaked on agar plates to determine the presence of MRSA and XDR A. baumannii. MRSA and XDR A. baumannii were recovered from all control surfaces. All surfaces cleaned with tap water or tap water containing detergent revealed presence of both MRSA and XDR A. baumannii. However the amounts of bacteria on the surfaces cleaned with tap water containing detergent were less than those cleaned with tap water alone. All surfaces cleaned with PAL disinfectant wipes also revealed presence of both MRSA and XDR A. baumannii. However the amounts of bacteria on the surfaces cleaned with PAL disinfectant wipes were less than those cleaned with tap water containing detergent. No bacteria were recovered from all surfaces cleaned with Virusolve+ disinfectant wipes. Virusolve+ disinfectant wipes were more effective than tap water; tap water containing detergent and PAL disinfectant wipes for decontamination of bacteria inoculated on patients environmental and medical equipment surfaces at Siriraj Hospital.

Reaction of water with MgO(100) surfaces: Part III. X-ray standing wave studies

NASA Astrophysics Data System (ADS)

Liu, P.; Kendelewicz, T.; Nelson, E. J.; Brown, G. E.

1998-09-01

Clean MgO(100) surfaces cleaved in vacuum and exposed to water vapor or bulk water were studied using the X-ray standing wave (XSW) technique in back reflection mode and surface sensitive, element specific O KLL and Mg KLL Auger electron yield detection. The effects of surface charging were mitigated, but not entirely eliminated, by using a low-energy electron flood gun. Simulation of the XSW signal showed that the effect of surface charging on the XSW data could be minimized with careful experimental design. We demonstrate that the XSW method can be applied to studies of insulating surfaces, and our results for MgO(100) surfaces exposed to water vapor or bulk water indicate the following: (1) the vacuum-cleaved clean surface undergoes no surface reconstruction or significant relaxation perpendicular to the surface; (2) Mg-OH distances on surfaces exposed to water vapor or bulk water measured perpendicular to the (100) surface are the same as in bulk MgO; and (3) the z-position of the surface Mg atoms does not change within the estimated error [±2% of the (200) spacing] after the surface is fully hydroxylated. Our results for the clean, vacuum-cleaved surface disagree with results from impact collision ion-scattering spectroscopy and surface-extended electron-loss fine structure for MgO(100), which indicate 15 and 17% inward relaxation, respectively, and they support results from low-energy electron diffraction, reflection high-energy electron diffraction, and photoelectron diffraction that show little, if any, relaxation or rumpling of the surface.

Surface restructuring behavior of various types of poly(dimethylsiloxane) in water detected by SFG.

PubMed

Chen, Chunyan; Wang, Jie; Chen, Zhan

2004-11-09

Surface structures of several different poly(dimethylsiloxane) (PDMS) materials, tetraethoxysilane-cured hydroxy-terminated PDMS (TEOS-PDMS), platinum-cured vinyl-terminated PDMS (Pt-PDMS), platinum-cured vinyl-terminated poly(diphenylsiloxane)-co-poly(dimethylsiloxane) (PDPS-co-PDMS), and PDMS-co-polystyrene (PDMS-co-PS) copolymer in air and water have been investigated by sum frequency generation (SFG) vibrational spectroscopy. The SFG spectra collected from all PDMS surfaces in both air and water are dominated by methyl group stretches, indicating that all the surfaces are mainly covered by methyl groups. Other than surface-dominating methyl groups, some -Si-CH2-CH2- moieties on the Pt-PDMS surface have also been detected in air, which are present at cross-linking points. Information about the average orientation angle and angle distribution of the methyl groups on the PDMS surface has been evaluated. Surface restructuring of the methyl groups has been observed for all PDMS surfaces in water. Upon contacting water, the methyl groups on all PDMS surfaces tilt more toward the surface. The detailed restructuring behaviors of several PDMS surfaces in water and the effects of molecular weight on restructuring behaviors have been investigated. For comparison, in addition to air and water, surface structures of PDMS materials mentioned above in a nonpolar solvent, FC-75, have also been studied. By comparing the different response of phenyl groups to water on both PDPS-co-PDMS and PS-co-PDMS surfaces, we have demonstrated how the restructuring behaviors of surface phenyl groups are affected by the structural flexibility of the molecular chains where they are attached.

Effective water surface mapping in macrophyte-covered reservoirs in NE Brazil based on TerraSAR-X time series

NASA Astrophysics Data System (ADS)

Zhang, Shuping; Foerster, Saskia; Medeiros, Pedro; de Araújo, José Carlos; Waske, Bjoern

2018-07-01

Water supplies in northeastern Brazil strongly depend on the numerous surface water reservoirs of various sizes there. However, the seasonal and long-term water surface dynamics of these reservoirs, particularly the large number of small ones, remain inadequately known. Remote sensing techniques have shown great potentials in water bodies mapping. Yet, the widespread presence of macrophytes in most of the reservoirs often impedes the delineation of the effective water surfaces. Knowledge of the dynamics of the effective water surfaces in the reservoirs is essential for understanding, managing, and modelling the local and regional water resources. In this study, a two-year time series of TerraSAR-X (TSX) satellite data was used to monitor the effective water surface areas in nine reservoirs in NE Brazil. Calm open water surfaces were obtained by segmenting the backscattering coefficients of TSX images with minimum error thresholding. Linear unmixing was implemented on the distributions of gray-level co-occurrence matrix (GLCM) variance in the reservoirs to quantify the proportions of sub-populations dominated by different types of scattering along the TSX time series. By referring to the statistics and the seasonal proportions of the GLCM variance sub-populations the GLCM variance was segmented to map the vegetated water surfaces. The effective water surface areas that include the vegetation-covered waters as well as calm open water in the reservoirs were mapped with accuracies >77%. The temporal and spatial change patterns of water surfaces in the nine reservoirs over a period of two consecutive dry and wet seasons were derived. Precipitation-related soil moisture changes, topography and the dense macrophyte canopies are the main sources of errors in the such-derived effective water surfaces. Independent from in-situ data, the approach employed in this study shows great potential in monitoring water surfaces of different complexity and macrophyte coverage. The effective water surface areas obtained for the reservoirs can provide valuable input for efficient water management and improve the hydrological modelling in this region.

First-principles study of water desorption from montmorillonite surface.

PubMed

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

2016-05-01

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

Fast MAS 1H NMR Study of Water Adsorption and Dissociation on the (100) Surface of Ceria Nanocubes: A Fully Hydroxylated, Hydrophobic Ceria Surface

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gill, Lance; Beste, Ariana; Chen, Banghao

1H nuclear magnetic resonance (NMR) spectroscopy was used to study hydroxylic surface species on ceria nanocubes, a crystalline, high-surface-area CeO 2 that presents mostly (100) facets. Water adsorption and desorption experiments in combination with fast magic angle spinning (MAS, 20–40 kHz) 1H NMR provide high-resolution 1H spectra that allow the observation of ten resonance bands (water or hydroxyl) on or under the (100) surface. Assignments were made using a combination of adsorption and temperature-programmed desorption, quantitative spin counting, deuterium exchange, spin–lattice (T 1) and spin–spin (T 2) relaxation, and DFT calculations. In air, the (100) surface exists as a fullymore » hydroxylated surface. Water adsorption and dissociation on dry ceria surfaces occur first at oxygen vacancies, but Ce 3+ centers are not required since water dissociation is barrier-less on the fully oxidized surface. Surface $-$OH functionality occurs in two resolved bands representing isolated $-$OH (1 ppm) and hydrogen-bonded $-$OH (9 ppm), the latter being dominant. Deuterium exchange of surface hydroxyls with D 2O does not occur under mild or forcing conditions. Despite large differences in the T 1 of surface hydroxyls and physisorbed water, surface hydroxyl T 1 values are independent of the presence or absence of physisorbed water, demonstrating that the protons within these two functional group pools are not in intimate contact. These observations show that, once hydroxylated, the surface $-$OH functionality preferentially forms hydrogen bonds with surface lattice oxygen, i.e., the hydroxylated (100) surface of ceria is hydrophobic. Near this surface it is energetically more favorable for physisorbed water to hydrogen bond to itself rather than to the surface. DFT calculations support this notion. Impurity Na + remaining in incompletely washed ceria nanocubes increases the surface hydrophilicity. In conclusion, sharp, low-field resonances observed in spectra of noncalcined nanocubes arise from kinetically trapped subsurface $-$OH.« less

Fast MAS 1H NMR Study of Water Adsorption and Dissociation on the (100) Surface of Ceria Nanocubes: A Fully Hydroxylated, Hydrophobic Ceria Surface

DOE PAGES

Gill, Lance; Beste, Ariana; Chen, Banghao; ...

2017-03-22

1H nuclear magnetic resonance (NMR) spectroscopy was used to study hydroxylic surface species on ceria nanocubes, a crystalline, high-surface-area CeO 2 that presents mostly (100) facets. Water adsorption and desorption experiments in combination with fast magic angle spinning (MAS, 20–40 kHz) 1H NMR provide high-resolution 1H spectra that allow the observation of ten resonance bands (water or hydroxyl) on or under the (100) surface. Assignments were made using a combination of adsorption and temperature-programmed desorption, quantitative spin counting, deuterium exchange, spin–lattice (T 1) and spin–spin (T 2) relaxation, and DFT calculations. In air, the (100) surface exists as a fullymore » hydroxylated surface. Water adsorption and dissociation on dry ceria surfaces occur first at oxygen vacancies, but Ce 3+ centers are not required since water dissociation is barrier-less on the fully oxidized surface. Surface $-$OH functionality occurs in two resolved bands representing isolated $-$OH (1 ppm) and hydrogen-bonded $-$OH (9 ppm), the latter being dominant. Deuterium exchange of surface hydroxyls with D 2O does not occur under mild or forcing conditions. Despite large differences in the T 1 of surface hydroxyls and physisorbed water, surface hydroxyl T 1 values are independent of the presence or absence of physisorbed water, demonstrating that the protons within these two functional group pools are not in intimate contact. These observations show that, once hydroxylated, the surface $-$OH functionality preferentially forms hydrogen bonds with surface lattice oxygen, i.e., the hydroxylated (100) surface of ceria is hydrophobic. Near this surface it is energetically more favorable for physisorbed water to hydrogen bond to itself rather than to the surface. DFT calculations support this notion. Impurity Na + remaining in incompletely washed ceria nanocubes increases the surface hydrophilicity. In conclusion, sharp, low-field resonances observed in spectra of noncalcined nanocubes arise from kinetically trapped subsurface $-$OH.« less

Design and Fabrication of a Hybrid Superhydrophobic-Hydrophilic Surface That Exhibits Stable Dropwise Condensation.

PubMed

Mondal, Bikash; Mac Giolla Eain, Marc; Xu, QianFeng; Egan, Vanessa M; Punch, Jeff; Lyons, Alan M

2015-10-28

Condensation of water vapor is an essential process in power generation, water collection, and thermal management. Dropwise condensation, where condensed droplets are removed from the surface before coalescing into a film, has been shown to increase the heat transfer efficiency and water collection ability of many surfaces. Numerous efforts have been made to create surfaces which can promote dropwise condensation, including superhydrophobic surfaces on which water droplets are highly mobile. However, the challenge with using such surfaces in condensing environments is that hydrophobic coatings can degrade and/or water droplets on superhydrophobic surfaces transition from the mobile Cassie to the wetted Wenzel state over time and condensation shifts to a less-effective filmwise mechanism. To meet the need for a heat-transfer surface that can maintain stable dropwise condensation, we designed and fabricated a hybrid superhydrophobic-hydrophilic surface. An array of hydrophilic needles, thermally connected to a heat sink, was forced through a robust superhydrophobic polymer film. Condensation occurs preferentially on the needle surface due to differences in wettability and temperature. As the droplet grows, the liquid drop on the needle remains in the Cassie state and does not wet the underlying superhydrophobic surface. The water collection rate on this surface was studied using different surface tilt angles, needle array pitch values, and needle heights. Water condensation rates on the hybrid surface were shown to be 4 times greater than for a planar copper surface and twice as large for silanized silicon or superhydrophobic surfaces without hydrophilic features. A convection-conduction heat transfer model was developed; predicted water condensation rates were in good agreement with experimental observations. This type of hybrid superhydrophobic-hydrophilic surface with a larger array of needles is low-cost, robust, and scalable and so could be used for heat transfer and water collection applications.

Thermophoretically driven water droplets on graphene and boron nitride surfaces.

PubMed

Rajegowda, Rakesh; Kannam, Sridhar Kumar; Hartkamp, Remco; Sathian, Sarith P

2018-05-25

We investigate thermally driven water droplet transport on graphene and hexagonal boron nitride (h-BN) surfaces using molecular dynamics simulations. The two surfaces considered here have different wettabilities with a significant difference in the mode of droplet transport. The water droplet travels along a straighter path on the h-BN sheet than on graphene. The h-BN surface produced a higher driving force on the droplet than the graphene surface. The water droplet is found to move faster on h-BN surface compared to graphene surface. The instantaneous contact angle was monitored as a measure of droplet deformation during thermal transport. The characteristics of the droplet motion on both surfaces is determined through the moment scaling spectrum. The water droplet on h-BN surface showed the attributes of the super-diffusive process, whereas it was sub-diffusive on the graphene surface.

Modulators of heterogeneous protein surface water dynamics

NASA Astrophysics Data System (ADS)

Han, Songi

The hydration water that solvates proteins is a major factor in driving or enabling biological events, including protein-protein and protein-ligand interactions. We investigate the role of the protein surface in modulating the hydration water fluctuations on both the picosecond and nanosecond timescale with an emerging experimental NMR technique known as Overhauser Dynamic Nuclear Polarization (ODNP). We carry out site-specific ODNP measurements of the hydration water fluctuations along the surface of Chemotaxis Y (CheY), and correlate the measured fluctuations to hydropathic and topological properties of the CheY surface as derived from molecular dynamics (MD) simulation. Furthermore, we compare hydration water fluctuations measured on the CheY surface to that of other globular proteins, as well as intrinsically disordered proteins, peptides, and liposome surfaces to systematically test characteristic effects of the biomolecular surface on the hydration water dynamics. Our results suggest that the labile (ps) hydration water fluctuations are modulated by the chemical nature of the surface, while the bound (ns) water fluctuations are present on surfaces that feature a rough topology and chemical heterogeneity such as the surface of a folded and structured protein. In collaboration with: Ryan Barnes, Dept of Chemistry and Biochemistry, University of California Santa Barbara

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

USGS Publications Warehouse

Reddy, Michael M.; Hoch, Anthony

2012-01-01

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

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

USGS Publications Warehouse

Reddy, M.M.; Hoch, A.

2012-01-01

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

Water at protein surfaces studied with femtosecond nonlinear spectroscopy

NASA Astrophysics Data System (ADS)

Bakker, Huib J.

We report on an investigation of the structure and dynamics of water molecules near protein surfaces with femtosecond nonlinear spectroscopic techniques. We measured the reorientation dynamics of water molecules near the surface of several globular protein surfaces, using polarization-resolved femtosecond infrared spectroscopy. We found that water molecules near the protein surface have a much slower reorientation than water molecules in bulk liquid water. The number of slow water molecules scales scales with the size of the hydrophobic surface of the protein. When we denature the proteins by adding an increasing amount of urea to the protein solution, we observe that the water-exposed surface increases by 50% before the secondary structure of the proteins changes. This finding indicates that protein unfolding starts with the protein structure becoming less tight, thereby allowing water to enter. With surface vibrational sum frequency generation (VSFG) spectroscopy, we studied the structure of water at the surface of antifreeze protein III. The measured VSFG spectra showed the presence of ice-like water layers at the ice-binding site of the protein in aqueous solution, at temperatures well above the freezing point. This ordered ice-like hydration layers at the protein surface likely plays an important role in the specific recognition and binding of anti-freeze protein III to nascent ice crystallites, and thus in its anti-freeze mechanism. This research is supported by the ''Nederlandse organisatie voor Wetenschappelijk Onderzoek (NWO).

Statistical robustness of machine-learning estimates for characterizing a groundwater-surface water system, Southland, New Zealand

NASA Astrophysics Data System (ADS)

Friedel, M. J.; Daughney, C.

2016-12-01

The development of a successful surface-groundwater management strategy depends on the quality of data provided for analysis. This study evaluates the statistical robustness when using a modified self-organizing map (MSOM) technique to estimate missing values for three hypersurface models: synoptic groundwater-surface water hydrochemistry, time-series of groundwater-surface water hydrochemistry, and mixed-survey (combination of groundwater-surface water hydrochemistry and lithologies) hydrostratigraphic unit data. These models of increasing complexity are developed and validated based on observations from the Southland region of New Zealand. In each case, the estimation method is sufficiently robust to cope with groundwater-surface water hydrochemistry vagaries due to sample size and extreme data insufficiency, even when >80% of the data are missing. The estimation of surface water hydrochemistry time series values enabled the evaluation of seasonal variation, and the imputation of lithologies facilitated the evaluation of hydrostratigraphic controls on groundwater-surface water interaction. The robust statistical results for groundwater-surface water models of increasing data complexity provide justification to apply the MSOM technique in other regions of New Zealand and abroad.

Hydrogen Isotopic Constraints on the Evolution of Surface and Subsurface Water on Mars

NASA Technical Reports Server (NTRS)

Usui, T.; Kurokawa, H.; Wang, J.; Alexander, C. M. O’D.; Simon, J. I.; Jones, J. H.

2017-01-01

The geology and geomorphology of Mars provide clear evidence for the presence of liquid water on its surface during the Noachian and Hesperien eras (i.e., >3 Ga). In contrast to the ancient watery environment, today the surface of Mars is relatively dry. The current desert-like surface conditions, however, do not necessarily indicate a lack of surface or near-surface water/ice. In fact, massive deposits of ground ice and/or icy sediments have been proposed based on subsurface radar sounder observations. Hence, accurate knowledge of both the evolution of the distribution of water and of the global water inventory is crucial to our understanding of the evolution of the climate and near-surface environments and the potential habitability of Mars. This study presents insights from hydrogen isotopes for the interactive evolution of Martian water reservoirs. In particular, based on our new measurement of the D/H ratio of 4 Ga-old Noachian water, we constrain the atmospheric loss and possible exchange of surface and subsurface water through time.

The effects of surface wettability on the fog and dew moisture harvesting performance on tubular surfaces

PubMed Central

Seo, Donghyun; Lee, Junghun; Lee, Choongyeop; Nam, Youngsuk

2016-01-01

The efficient water harvesting from air-laden moisture has been a subject of great interest to address world-wide water shortage issues. Recently, it has been shown that tailoring surface wettability can enhance the moisture harvesting performance. However, depending on the harvesting condition, a different conclusion has often been reported and it remains unclear what type of surface wettability would be desirable for the efficient water harvesting under the given condition. Here we compare the water harvesting performance of the surfaces with various wettability under two different harvesting conditions–dewing and fogging, and show that the different harvesting efficiency of each surface under these two conditions can be understood by considering the relative importance of the water capturing and removal efficiency of the surface. At fogging, the moisture harvesting performance is determined by the water removal efficiency of the surface with the oil-infused surfaces exhibiting the best performance. Meanwhile, at dewing, both the water capturing and removal efficiency are crucial to the harvesting performance. And well-wetting surfaces with a lower barrier to nucleation of condensates exhibit a better harvesting performance due to the increasing importance of the water capture efficiency over the water removal efficiency at dewing. PMID:27063149

Village-level supply reliability of surface water irrigation in rural China: effects of climate change

NASA Astrophysics Data System (ADS)

Li, Yanrong; Wang, Jinxia

2018-06-01

Surface water, as the largest part of water resources, plays an important role on China's agricultural production and food security. And surface water is vulnerable to climate change. This paper aims to examine the status of the supply reliability of surface water irrigation, and discusses how it is affected by climate change in rural China. The field data we used in this study was collected from a nine-province field survey during 2012 and 2013. Climate data are offered by China's National Meteorological Information Center which contains temperature and precipitation in the past 30 years. A Tobit model (or censored regression model) was used to estimate the influence of climate change on supply reliability of surface water irrigation. Descriptive results showed that, surface water supply reliability was 74 % in the past 3 years. Econometric results revealed that climate variables significantly influenced the supply reliability of surface water irrigation. Specifically, temperature is negatively related with the supply reliability of surface water irrigation; but precipitation positively influences the supply reliability of surface water irrigation. Besides, climate influence differs by seasons. In a word, this paper improves our understanding of the impact of climate change on agriculture irrigation and water supply reliability in the micro scale, and provides a scientific basis for relevant policy making.

A deformable surface model for real-time water drop animation.

PubMed

Zhang, Yizhong; Wang, Huamin; Wang, Shuai; Tong, Yiying; Zhou, Kun

2012-08-01

A water drop behaves differently from a large water body because of its strong viscosity and surface tension under the small scale. Surface tension causes the motion of a water drop to be largely determined by its boundary surface. Meanwhile, viscosity makes the interior of a water drop less relevant to its motion, as the smooth velocity field can be well approximated by an interpolation of the velocity on the boundary. Consequently, we propose a fast deformable surface model to realistically animate water drops and their flowing behaviors on solid surfaces. Our system efficiently simulates water drop motions in a Lagrangian fashion, by reducing 3D fluid dynamics over the whole liquid volume to a deformable surface model. In each time step, the model uses an implicit mean curvature flow operator to produce surface tension effects, a contact angle operator to change droplet shapes on solid surfaces, and a set of mesh connectivity updates to handle topological changes and improve mesh quality over time. Our numerical experiments demonstrate a variety of physically plausible water drop phenomena at a real-time rate, including capillary waves when water drops collide, pinch-off of water jets, and droplets flowing over solid materials. The whole system performs orders-of-magnitude faster than existing simulation approaches that generate comparable water drop effects.

Investigation of surface water behavior during glaze ice accretion

NASA Technical Reports Server (NTRS)

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

1990-01-01

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

Monitoring monthly surface water dynamics of Dongting Lake using Sentinel-1 data at 10 m.

PubMed

Xing, Liwei; Tang, Xinming; Wang, Huabin; Fan, Wenfeng; Wang, Guanghui

2018-01-01

High temporal resolution water distribution maps are essential for surface water monitoring because surface water exhibits significant inner-annual variation. Therefore, high-frequency remote sensing data are needed for surface water mapping. Dongting Lake, the second-largest freshwater lake in China, is famous for the seasonal fluctuations of its inundation extents in the middle reaches of the Yangtze River. It is also greatly affected by the Three Gorges Project. In this study, we used Sentinel-1 data to generate surface water maps of Dongting Lake at 10 m resolution. First, we generated the Sentinel-1 time series backscattering coefficient for VH and VV polarizations at 10 m resolution by using a monthly composition method. Second, we generated the thresholds for mapping surface water at 10 m resolution with monthly frequencies using Sentinel-1 data. Then, we derived the monthly surface water distribution product of Dongting Lake in 2016, and finally, we analyzed the inner-annual surface water dynamics. The results showed that: (1) The thresholds were -21.56 and -15.82 dB for the backscattering coefficients for VH and VV, respectively, and the overall accuracy and Kappa coefficients were above 95.50% and 0.90, respectively, for the VH backscattering coefficient, and above 94.50% and 0.88, respectively, for the VV backscattering coefficient. The VV backscattering coefficient achieved lower accuracy due to the effect of the wind causing roughness on the surface of the water. (2) The maximum and minimum areas of surface water were 2040.33 km 2 in July, and 738.89 km 2 in December. The surface water area of Dongting Lake varied most significantly in April and August. The permanent water acreage in 2016 was 556.35 km 2 , accounting for 19.65% of the total area of Dongting Lake, and the acreage of seasonal water was 1525.21 km 2 . This study proposed a method to automatically generate monthly surface water at 10 m resolution, which may contribute to monitoring surface water in a timely manner.

Quantifying the Contribution of Regional Aquifers to Stream Flow in the Upper Colorado River Basin

NASA Astrophysics Data System (ADS)

Masbruch, M.; Dickinson, J.

2017-12-01

The growing population of the arid and semiarid southwestern U.S. relies on over-allocated surface water resources and poorly quantified groundwater resources. In the Upper Colorado River Basin, recent studies have found that about 50 percent of the surface water at U.S. Geological Survey (USGS) stream gages is derived from groundwater contributions as base flow. Prior USGS and other studies for the Colorado Plateau region have mainly examined groundwater and surface water as separate systems, and there has yet to be regional synthesis of groundwater availability in aquifers that contribute to surface water. A more physically based representation of groundwater flow could improve simulations of surface-water capture by groundwater pumping, and changes of groundwater discharge to surface water caused by possible shifts in the distribution, magnitude, and timing of recharge in the future. We seek to improve conceptual and numerical models of groundwater and surface-water interactions in the Colorado Plateau region as part of a USGS regional groundwater availability assessment. Numerical modeling is used to simulate and quantify the base flow from groundwater to the Colorado River and its major tributaries. Groundwater/surface-water interactions will be simulated using the USGS code GSFLOW, which couples the Precipitation Runoff Modeling System (PRMS) to the groundwater flow model MODFLOW. Initial results suggest that interactions between groundwater and surface water are important for projecting long-term changes in surface water budgets.

The glass-liquid transition of water on hydrophobic surfaces

NASA Astrophysics Data System (ADS)

Souda, Ryutaro

2008-09-01

Interactions of thin water films with surfaces of graphite and vitrified room-temperature ionic liquid [1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6])] 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 120K, thereby forming three-dimensional clusters (a two-dimensional layer) on the [bmim][PF6] (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 (140K). Results also showed that aging is necessary for the water monolayer (a 40 ML water film) to dewet the graphite ([bmim][PF6]) 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][PF6] 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.

Water resources of the Prairie Island Indian Reservation, Minnesota, 1994-97

USGS Publications Warehouse

Cowdery, Timothy K.

1999-01-01

The only surface-water constituents exceeding U.S. Environmental Protection Agency drinking water standards was coliform or fecal streptococci bacteria, which was exceeded in all samples. Thirteen percent of ground-water samples exceeded the nitrate maximum contaminant level (MCL), but this is probably higher than the percentage of the aquifer exceeding the nitrate MCL because most of the wells sampled were shallow. Surface-water recharge to and ground-water discharge from the surficial aquifer influence the water quality in both the aquifer and the surrounding surface water. However, surface water probably influences ground-water quality more because of the greater amount of surface water flowing through the study area.

Escape jumping by three age-classes of water striders from smooth, wavy and bubbling water surfaces.

PubMed

Ortega-Jimenez, Victor Manuel; von Rabenau, Lisa; Dudley, Robert

2017-08-01

Surface roughness is a ubiquitous phenomenon in both oceanic and terrestrial waters. For insects that live at the air-water interface, such as water striders, non-linear and multi-scale perturbations produce dynamic surface deformations which may impair locomotion. We studied escape jumps of adults, juveniles and first-instar larvae of the water strider Aquarius remigis on smooth, wave-dominated and bubble-dominated water surfaces. Effects of substrate on takeoff jumps were substantial, with significant reductions in takeoff angles, peak translational speeds, attained heights and power expenditure on more perturbed water surfaces. Age effects were similarly pronounced, with the first-instar larvae experiencing the greatest degradation in performance; age-by-treatment effects were also significant for many kinematic variables. Although commonplace in nature, perturbed water surfaces thus have significant and age-dependent effects on water strider locomotion, and on behavior more generally of surface-dwelling insects. © 2017. Published by The Company of Biologists Ltd.

Critical Dipole Length for the Wetting Transition Due to Collective Water-dipoles Interactions

PubMed Central

Wang, Chunlei; Zhou, Bo; Tu, Yusong; Duan, Manyi; Xiu, Peng; Li, Jingye; Fang, Haiping

2012-01-01

The wetting behavior of water on the solid surfaces is fundamental to various physical, chemical and biological processes. Conventionally, the surface with charges or charge dipoles is hydrophilic, whereas the non-polar surface is hydrophobic though some exceptions were recently reported. Using molecular dynamics simulations, we show that there is a critical length of the charge dipoles on the solid surface. The solid surface still exhibited hydrophobic behavior when the dipole length was less than the critical value, indicating that the water molecules on the solid surface seemed not “feel” attractive interactions from the charge dipoles on the solid surface. Those unexpected observations result from the collective interactions between the water molecules and charge dipoles on the solid surface, where the steric exclusion effect between water molecules greatly reduces the water-dipole interactions. Remarkably, the steric exclusion effect is also important for surfaces with charge dipole lengths greater than this critical length. PMID:22496954

A robust Multi-Band Water Index (MBWI) for automated extraction of surface water from Landsat 8 OLI imagery

NASA Astrophysics Data System (ADS)

Wang, Xiaobiao; Xie, Shunping; Zhang, Xueliang; Chen, Cheng; Guo, Hao; Du, Jinkang; Duan, Zheng

2018-06-01

Surface water is vital resources for terrestrial life, while the rapid development of urbanization results in diverse changes in sizes, amounts, and quality of surface water. To accurately extract surface water from remote sensing imagery is very important for water environment conservations and water resource management. In this study, a new Multi-Band Water Index (MBWI) for Landsat 8 Operational Land Imager (OLI) images is proposed by maximizing the spectral difference between water and non-water surfaces using pure pixels. Based on the MBWI map, the K-means cluster method is applied to automatically extract surface water. The performance of MBWI is validated and compared with six widely used water indices in 29 sites of China. Results show that our proposed MBWI performs best with the highest accuracy in 26 out of the 29 test sites. Compared with other water indices, the MBWI results in lower mean water total errors by a range of 9.31%-25.99%, and higher mean overall accuracies and kappa coefficients by 0.87%-3.73% and 0.06-0.18, respectively. It is also demonstrated for MBWI in terms of robustly discriminating surface water from confused backgrounds that are usually sources of surface water extraction errors, e.g., mountainous shadows and dark built-up areas. In addition, the new index is validated to be able to mitigate the seasonal and daily influences resulting from the variations of the solar condition. MBWI holds the potential to be a useful surface water extraction technology for water resource studies and applications.

Dynamics of water confined on the surface of titania and cassiterite nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ross, Dr. Nancy; Spencer, Elinor; Levchenko, Andrey A.

2011-01-01

We present low-temperature inelastic neutron scattering spectra collected on two metal oxide nanoparticle systems, isostructural TiO2 rutile and SnO2 cassiterite, between 0-550 meV. Data were collected on samples with varying levels of water coverage, and in the case of SnO2, particles of different sizes. This study provides a comprehensive understanding of the structure and dynamics of the water confined on the surface of these particles. The translational movement of water confined on the surface of these nanoparticles is suppressed relative to that in ice-Ih and water molecules on the surface of rutile nanoparticles are more strongly restrained that molecules residingmore » on the surface of cassiterite nanoparticles. The INS spectra also indicate that the hydrogen bond network within the hydration layers on rutile is more perturbed than for water on cassiterite. This result is indicative of stronger water-surface interactions between water on the rutile nanoparticles than for water confined on the surface of cassiterite nanoparticles. These differences are consistent with the recently reported differences in the surface energy of these two nanoparticle systems. The results of this study also support previous studies that suggest that water dissociation is more prevalent on the surface of SnO2 than TiO2.« less

Distribution of volatile organic compounds (VOCs) in surface water, soil, and groundwater within a chemical industry park in Eastern China.

PubMed

Liu, Benhua; Chen, Liang; Huang, Linxian; Wang, Yongseng; Li, Yuehua

2015-01-01

This paper focuses on the distribution of volatile organic compounds (VOCs) in the surface water, soil, and groundwater within a chemical industry park in Eastern China. At least one VOC was detected in each of the 20 sampling sites, and the maximum number of VOCs detected in the surface water, groundwater, and soil were 13, 16, and 14, respectively. Two of the 10 VOCs with elevated concentrations detected in surface water, groundwater, and soil were chloroform and 1,2-dichloroethane. The characteristics of VOCs, which include volatility, boiling point, and solubility, could significantly affect their distribution in surface water, soil, and groundwater. However, due to the direct discharging of chemical industry wastewater into surface water, higher concentrations of VOCs (except chloroform) were detected in surface water than in soil and groundwater. Fortunately, the higher volatility of VOCs prevents the VOCs from impacting groundwater, which helps to maintain a lower concentration of VOCs in the groundwater than in both surface water and soil. This is because pollutants with relatively higher boiling points and lower solubilities have higher detection frequencies in soil, and contaminants with relatively lower boiling points and higher solubilities have higher detection frequencies in water, notably in surface water.

Water Adsorption on Clean and Defective Anatase TiO2 (001) Nanotube Surfaces: A Surface Science Approach.

PubMed

Kenmoe, Stephane; Lisovski, Oleg; Piskunov, Sergei; Bocharov, Dmitry; Zhukovskii, Yuri F; Spohr, Eckhard

2018-05-31

We use ab initio molecular dynamics simulations to study the adsorption of thin water films with 1 and 2 ML coverage on anatase TiO 2 (001) nanotubes. The nanotubes are modeled as 2D slabs, which consist of partially constrained and partially relaxed structural motifs from nanotubes. The effect of anion doping on the adsorption is investigated by substituting O atoms with N and S impurities on the nanotube slab surface. Due to strain-induced curvature effects, water adsorbs molecularly on defect-free surfaces via weak bonds on Ti sites and H bonds to surface oxygens. While the introduction of an S atom weakens the interaction of the surface with water, which adsorbs molecularly, the presence of an N impurity renders the surface more reactive to water, with a proton transfer from the water film and the formation of an NH group at the N site. At 2 ML coverage, a further surface-assisted proton transfer takes place in the water film, resulting in the formation of an OH - group and an NH 2 + cationic site on the surface.

Transfer of Materials from Water to Solid Surfaces Using Liquid Marbles.

PubMed

Kawashima, Hisato; Paven, Maxime; Mayama, Hiroyuki; Butt, Hans-Jürgen; Nakamura, Yoshinobu; Fujii, Syuji

2017-09-27

Remotely controlling the movement of small objects is desirable, especially for the transportation and selection of materials. Transfer of objects between liquid and solid surfaces and triggering their release would allow for development of novel material transportation technology. Here, we describe the remote transport of a material from a water film surface to a solid surface using quasispherical liquid marbles (LMs). A light-induced Marangoni flow or an air stream is used to propel the LMs on water. As the LMs approach the rim of the water film, gravity forces them to slide down the water rim and roll onto the solid surface. Through this method, LMs can be efficiently moved on water and placed on a solid surface. The materials encapsulated within LMs can be released at a specific time by an external stimulus. We analyzed the velocity, acceleration, and force of the LMs on the liquid and solid surfaces. On water, the sliding friction due to the drag force resists the movement of the LMs. On a solid surface, the rolling distance is affected by the surface roughness of the LMs.

Orientation-dependent hydration structures at yttria-stabilized cubic zirconia surfaces

DOE PAGES

Hou, Binyang; Kim, Seunghyun; Kim, Taeho; ...

2016-11-30

Water interaction with surfaces is very important and plays key roles in many natural and technological processes. Because the experimental challenges that arise when studying the interaction water with specific crystalline surfaces, most studies on metal oxides have focused on powder samples, which averaged the interaction over different crystalline surfaces. As a result, studies on the crystal orientation-dependent interaction of water with metal oxides are rarely available in the literature. In this work, water adsorption at 8 mol % yttria-stabilized cubic single crystal zirconia (100) and (111) surfaces was studied in terms of interfacial hydration structures using high resolution X-raymore » reflectivity measurements. The interfacial electron density profiles derived from the structure factor analysis of the measured data show the existence of multiple layers of adsorbed water with additional peculiar metal adsorption near the oxide surfaces.Surface relaxation, depletion, and interaction between the adsorbed layers and bulk water are found to vary greatly between the two surfaces and are also different when compared to the previously studied (110) surface. The fractional ratio between chemisorbed and physisorbed water species were also quantitatively estimated, which turned out to vary dramatically from surface to surface. Finally, the result gives us a unique opportunity to reconsider the simplified 2:1 relation between chemisorption and physisorption, originally proposed by Morimoto et al. based on the adsorption isotherms of water on powder metal oxide samples.« less

Surface freezing of water.

PubMed

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

2016-01-01

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

Electrohydrodynamic behavior of water droplets on a horizontal super hydrophobic surface and its self-cleaning application

NASA Astrophysics Data System (ADS)

Li, Jian; Wei, Yuan; Huang, Zhengyong; Wang, Feipeng; Yan, Xinzhu; Wu, Zhuolin

2017-05-01

Moisture is a significant factor that affects the insulation performance of outdoor high-voltage insulators in power systems. Accumulation of water droplets on insulators causes severe problems such as flashover of insulators and power outage. In this study, we develop a method to fabricate a micro/nano hierarchical super hydrophobic surface. The as-prepared super hydrophobic surface exhibits a water contact angle (WCA) of 160.4 ± 2°, slide angle (SA) less than 1° and surface free energy (SFE) of 5.99 mJ/m2. We investigated the electrohydropdynamic behavior of water droplet on a horizontal super hydrophobic surface compared with hydrophobic RTV silicone rubber surface which was widely used as anti-pollution coating or shed material of composite insulator. Results show that water droplet tended to a self-propelled motion on the super hydrophobic surface while it tended to elongate and break up on the RTV surface. The micro/nano hierarchical surface structure and chemical components with low surface free energy of the super hydrophobic surface jointly contributed to the reduction of skin fraction drag and subsequently made it possible for the motion of water droplet driven by electric field. Furthermore, the self-propelled motion of water droplets could also sweep away contaminations along its moving trace, which provides super hydrophobic surface a promising anti-pollution prospect in power systems.

First-principles molecular dynamics study of water dissociation on the γ-U(1 0 0) surface

NASA Astrophysics Data System (ADS)

Yang, Yu; Zhang, Ping

2015-05-01

Based on first-principles molecular dynamics simulations at finite temperatures, we systematically study the adsorption and dissociation of water molecules on the γ-U(1 0 0) surface. We predict that water molecules spontaneously dissociate upon approaching the native γ-U(1 0 0) surface. The dissociation results from electronic interactions between surface uranium 6d states and 1b2, 3a1, and 1b1 molecular orbitals of water. With segregated Nb atoms existing on the surface, adsorbing water molecules also dissociate spontaneously because Nb 3d electronic states can also interact with the molecular orbitals similarly. After dissociation, the isolated hydrogen atoms are found to diffuse fast on both the γ-U surface and that with a surface substitutional Nb atom, which is very similar to the ‘Hot-Atom’ dissociation of oxygen molecules on the Al(1 1 1) surface. From a series of consecutive molecular dynamics simulations, we further reveal that on both the γ-U surface and that with a surface substitutional Nb atom, one surface U atom will be pulled out to form the U-O-U structure after dissociative adsorption of 0.44 ML water molecules. This result indicates that oxide nucleus can form at low coverage of water adsorption on the two surfaces.

Insight into Chemistry on Cloud/Aerosol Water Surfaces.

PubMed

Zhong, Jie; Kumar, Manoj; Francisco, Joseph S; Zeng, Xiao Cheng

2018-05-15

Cloud/aerosol water surfaces exert significant influence over atmospheric chemical processes. Atmospheric processes at the water surface are observed to follow mechanisms that are quite different from those in the gas phase. This Account summarizes our recent findings of new reaction pathways on the water surface. We have studied these surface reactions using Born-Oppenheimer molecular dynamics simulations. These studies provide useful information on the reaction time scale, the underlying mechanism of surface reactions, and the dynamic behavior of the product formed on the aqueous surface. According to these studies, the aerosol water surfaces confine the atmospheric species into a specific orientation depending on the hydrophilicity of atmospheric species or the hydrogen-bonding interactions between atmospheric species and interfacial water. As a result, atmospheric species are activated toward a particular reaction on the aerosol water surface. For example, the simplest Criegee intermediate (CH 2 OO) exhibits high reactivity toward the interfacial water and hydrogen sulfide, with the reaction times being a few picoseconds, 2-3 orders of magnitude faster than that in the gas phase. The presence of interfacial water molecules induces proton-transfer-based stepwise pathways for these reactions, which are not possible in the gas phase. The strong hydrophobicity of methyl substituents in larger Criegee intermediates (>C1), such as CH 3 CHOO and (CH 3 ) 2 COO, blocks the formation of the necessary prereaction complexes for the Criegee-water reaction to occur at the water droplet surface, which lowers their proton-transfer ability and hampers the reaction. The aerosol water surface provides a solvent medium for acids (e.g., HNO 3 and HCOOH) to participate in reactions via mechanisms that are different from those in the gas and bulk aqueous phases. For example, the anti-CH 3 CHOO-HNO 3 reaction in the gas phase follows a direct reaction between anti-CH 3 CHOO and HNO 3 , whereas on a water surface, the HNO 3 -mediated stepwise hydration of anti-CH 3 CHOO is dominantly observed. The high surface/volume ratio of interfacial water molecules at the aerosol water surface can significantly lower the energy barriers for the proton transfer reactions in the atmosphere. Such catalysis by the aerosol water surface is shown to cause the barrier-less formation of ammonium bisulfate from hydrated NH 3 and SO 3 molecules rather than from the reaction of H 2 SO 4 with NH 3 . Finally, an aerosol water droplet is a polar solvent, which would favorably interact with high polarity substrates. This can accelerate interconversion of different conformers (e.g., anti and syn) of atmospheric species, such as glyoxal, depending on their polarity. The results discussed here enable an improved understanding of atmospheric processes on the aerosol water surface.

Heterogeneous Ice Nucleation: Interplay of Surface Properties and Their Impact on Water Orientations.

PubMed

Glatz, Brittany; Sarupria, Sapna

2018-01-23

Ice is ubiquitous in nature, and heterogeneous ice nucleation is the most common pathway of ice formation. How surface properties affect the propensity to observe ice nucleation on that surface remains an open question. We present results of molecular dynamics studies of heterogeneous ice nucleation on model surfaces. The models surfaces considered emulate the chemistry of kaolinite, an abundant component of mineral dust. We investigate the interplay of surface lattice and hydrogen bonding properties in affecting ice nucleation. We find that lattice matching and hydrogen bonding are necessary but not sufficient conditions for observing ice nucleation at these surfaces. We correlate this behavior to the orientations sampled by the metastable supercooled water in contact with the surfaces. We find that ice is observed in cases where water molecules not only sample orientations favorable for bilayer formation but also do not sample unfavorable orientations. This distribution depends on both surface-water and water-water interactions and can change with subtle modifications to the surface properties. Our results provide insights into the diverse behavior of ice nucleation observed at different surfaces and highlight the complexity in elucidating heterogeneous ice nucleation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Jian; Guo, Pan; University of Chinese Academy of Sciences, Beijing 100049

Using molecular dynamics simulations, we show a fine linear relationship between surface energies and microscopic Lennard-Jones parameters of super-hydrophilic surfaces. The linear slope of the super-hydrophilic surfaces is consistent with the linear slope of the super-hydrophobic, hydrophobic, and hydrophilic surfaces where stable water droplets can stand, indicating that there is a universal linear behavior of the surface energies with the water-surface van der Waals interaction that extends from the super-hydrophobic to super-hydrophilic surfaces. Moreover, we find that the linear relationship exists for various substrate types, and the linear slopes of these different types of substrates are dependent on the surfacemore » atom density, i.e., higher surface atom densities correspond to larger linear slopes. These results enrich our understanding of water behavior on solid surfaces, especially the water wetting behaviors on uncharged super-hydrophilic metal surfaces.« less

The Interaction of Water with Solid Surfaces: Fundamental Aspects Revisited

DOE Office of Scientific and Technical Information (OSTI.GOV)

Henderson, Michael A.

2002-05-01

Water is perhaps the most important and most pervasive chemical on our planet. The influence of water permeates virtually all areas of biochemical, chemical and physical importance, and is especially evident in phenomena occurring at the interfaces of solid surfaces. Since 1987, when Thiel and Madey (TM) published their review titled "The Interaction of Water with Solid Surfaces: Fundamental Aspects" in Surface Science Reports, there has been considerable progress made in further understanding the fundamental interactions of water with solid surfaces. In the decade and a half, the increased capability of surface scientists to probe at the molecular-level has resultedmore » in more detailed information of the properties of water on progressively more complicated materials and under more stringent conditions. This progress in understanding the properties of water on solid surfaces is evident both in areas for which surface science methodology has traditionally been strong (catalysis and electronic materials) and also in new areas not traditionally studied by surface scientists, such as electrochemistry, photoconversion, mineralogy, adhesion, sensors, atmospheric chemistry, and tribology. Researchers in all these fields grapple with very basic questions regarding the interactions of water with solid surfaces, such as how is water adsorbed, what are the chemical and electrostatic forces that constitute the adsorbed layer, how is water thermally or non-thermally activated, and how do coadsorbates influence these properties of water. The attention paid to these and other fundamental questions in the past decade and a half has been immense. In this review, experimental studies published since the TM review are assimilated with those covered by TM to provide a current picture of the fundamental interactions of water with solid surfaces.« less

Experimental study on soluble chemical transfer to surface runoff from soil.

PubMed

Tong, Juxiu; Yang, Jinzhong; Hu, Bill X; Sun, Huaiwei

2016-10-01

Prevention of chemical transfer from soil to surface runoff, under condition of irrigation and subsurface drainage, would improve surface water quality. In this paper, a series of laboratory experiments were conducted to assess the effects of various soil and hydraulic factors on chemical transfer from soil to surface runoff. The factors include maximum depth of ponding water on soil surface, initial volumetric water content of soil, depth of soil with low porosity, type or texture of soil and condition of drainage. In the experiments, two soils, sand and loam, mixed with different quantities of soluble KCl were filled in the sandboxes and prepared under different initial saturated conditions. Simulated rainfall induced surface runoff are operated in the soils, and various ponding water depths on soil surface are simulated. Flow rates and KCl concentration of surface runoff are measured during the experiments. The following conclusions are made from the study results: (1) KCl concentration in surface runoff water would decrease with the increase of the maximum depth of ponding water on soil surface; (2) KCl concentration in surface runoff water would increase with the increase of initial volumetric water content in the soil; (3) smaller depth of soil with less porosity or deeper depth of soil with larger porosity leads to less KCl transfer to surface runoff; (4) the soil with finer texture, such as loam, could keep more fertilizer in soil, which will result in more KCl concentration in surface runoff; and (5) good subsurface drainage condition will increase the infiltration and drainage rates during rainfall event and will decrease KCl concentration in surface runoff. Therefore, it is necessary to reuse drained fertile water effectively during rainfall, without polluting groundwater. These study results should be considered in agriculture management to reduce soluble chemical transfer from soil to surface runoff for reducing non-point sources pollution.

Use of chemical and isotopic tracers to characterize the interactions between ground water and surface water in mantled karst

USGS Publications Warehouse

Katz, B.G.; Coplen, T.B.; Bullen, T.D.; Hal, Davis J.

1997-01-01

In the mantled karst terrane of northern Florida, the water quality of the Upper Floridan aquifer is influenced by the degree of connectivity between the aquifer and the surface. Chemical and isotopic analyses [18O/16O (??18O), 2H/1H (??D), 13C/12C (??13C), tritium(3H), and strontium-87/strontium-86(87Sr/86Sr)]along with geochemical mass-balance modeling were used to identify the dominant hydrochemical processes that control the composition of ground water as it evolves downgradient in two systems. In one system, surface water enters the Upper Floridan aquifer through a sinkhole located in the Northern Highlands physiographic unit. In the other system, surface water enters the aquifer through a sinkhole lake (Lake Bradford) in the Woodville Karst Plain. Differences in the composition of water isotopes (??18O and ??D) in rainfall, ground water, and surface water were used to develop mixing models of surface water (leakage of water to the Upper Floridan aquifer from a sinkhole lake and a sinkhole) and ground water. Using mass-balance calculations, based on differences in ??18O and ??D, the proportion of lake water that mixed with meteoric water ranged from 7 to 86% in water from wells located in close proximity to Lake Bradford. In deeper parts of the Upper Floridan aquifer, water enriched in 18O and D from five of 12 sampled municipal wells indicated that recharge from a sinkhole (1 to 24%) and surface water with an evaporated isotopic signature (2 to 32%) was mixing with ground water. The solute isotopes, ??13C and 87Sr/86Sr, were used to test the sensitivity of binary and ternary mixing models, and to estimate the amount of mass transfer of carbon and other dissolved species in geochemical reactions. In ground water downgradient from Lake Bradford, the dominant processes controlling carbon cycling in ground water were dissolution of carbonate minerals, aerobic degradation of organic matter, and hydrolysis of silicate minerals. In the deeper parts of the Upper Floridan aquifer, the major processes controlling the concentrations of major dissolved species included dissolution of calcite and dolomite, and degradation of organic matter under oxic conditions. The Upper Floridan aquifer is highly susceptible to contamination from activities at the land surface in the Tallahassee area. The presence of post-1950s concentrations of 3H in ground water from depths greater than 100 m below land surface indicates that water throughout much of the Upper Floridan aquifer has been recharged during the last 40 years. Even though mixing is likely between ground water and surface water in many parts of the study area, the Upper Floridan aquifer produces good quality water, which due to dilution effects shows little if any impact from trace elements or nutrients that are present in surface waters.The water quality of the Upper Floridan aquifer is influenced by the degree of connectivity between the aquifer and the surface water. Chemical and isotopic analyses, tritium, and strontium-87/strontium-86 along with geochemical mass-balance modeling were used to identify the dominant hydrochemical processes that control the composition of groundwater. Differences in the composition of water isotopes in rainfall, groundwater and surface water were used to develop mixing models of surface water and groundwater. Even though mixing is likely between groundwater and surface water in many parts of the study area, the Upper Floridan aquifer produces good quality water, showing little impact from trace elements present in surface waters.

The humidity dependence of ozone deposition onto a variety of building surfaces

NASA Astrophysics Data System (ADS)

Grøntoft, Terje; Henriksen, Jan F.; Seip, Hans M.

Measurements of the dry deposition velocity of O 3 to material samples of calcareous stone, concrete and wood at varying humidity of the air, were performed in a deposition chamber. Equilibrium surface deposition velocities were found for various humidity values by fitting a model to the time-dependent deposition data. A deposition velocity-humidity model was derived giving three separate rate constants for the surface deposition velocities, i.e. on the dry surface, on the first mono-layer of adsorbed water and on additional surface water. The variation in the dry air equilibrium surface deposition velocities among the samples correlated with variations in effective areas, with larger effective areas giving higher measured deposition velocities. A minimum for the equilibrium surface deposition velocity was generally measured at an intermediate humidity close to the humidity found to correspond to one mono-layer of water molecules on the surfaces. At low air humidity the equilibrium surface deposition velocity of O 3 was found to decrease as more adsorbed water prevented direct contact of the O 3 molecules with the surface. This was partly compensated by an increase as more adsorbed water became available for reaction with O 3. At high air humidity the equilibrium surface deposition velocity was found to increase as the mass of water on the surface increased. The deposition velocity on bulk de-ionised water at RH=90% was an order of magnitude lower than on the sample surfaces.

Quality of water and chemistry of bottom sediment in the Rillito Creek basin, Tucson, Arizona, 1992-93

USGS Publications Warehouse

Tadayon, Saeid

1995-01-01

Physical and chemical data were collected from four surface-water sites, six ground-water sites, and two bottom-sediment sites during 1992-93. Specific conductance, hardness, alkalinity, and dissolved- solids concentrations generally were higher in ground water than in surface water. The median concentrations of dissolved major ions, with the exception of potassium, were higher in ground water than in surface water. In surface water and ground water, calcium was the dominant cation, and bicarbonate was the dominant anion. Concentrations of dissolved nitrite and nitrite plus nitrate in surface water and ground water did not exceed the U.S. Environmental Protection Agency maximum contaminant levels of 1 and 10 milligrams per liter for drinking water, respectively. Ammonium plus organic nitrogen in bottom sediment was detected at the highest concentration of any nitrogen species. Median values for most of the dissolved trace elements in surface water and ground water were below the detection levels. Dissolved trace elements in surface water and ground water did not exceed the U.S. Environmental Protection Agency maximum contaminant levels for drinking water. Trace-element concentrations in bottom sediment were similar to trace-element concentrations reported for soils of the western conterminous United States. Several organochlorine pesticides and priority pollutants were detected in surface-water and bottom-sediment samples; however, they did not exceed water-quality standards. Pesticides or priority pollutants were not detected in ground-water samples.

Long Term 2 Second Round Source Water Monitoring and Bin Placement Memo

EPA Pesticide Factsheets

The Long Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR) applies to all public water systems served by a surface water source or public water systems served by a ground water source under the direct influence of surface water.

A conceptual model for the analysis of multi-stressors in linked groundwater-surface water systems.

PubMed

Kaandorp, Vince P; Molina-Navarro, Eugenio; Andersen, Hans E; Bloomfield, John P; Kuijper, Martina J M; de Louw, Perry G B

2018-06-15

Groundwater and surface water are often closely coupled and are both under the influence of multiple stressors. Stressed groundwater systems may lead to a poor ecological status of surface waters but to date no conceptual framework to analyse linked multi-stressed groundwater - surface water systems has been developed. In this paper, a framework is proposed showing the effect of groundwater on surface waters in multiple stressed systems. This framework will be illustrated by applying it to four European catchments, the Odense, Denmark, the Regge and Dinkel, Netherlands, and the Thames, UK, and by assessing its utility in analysing the propagation or buffering of multi-stressors through groundwater to surface waters in these catchments. It is shown that groundwater affects surface water flow, nutrients and temperature, and can both propagate stressors towards surface waters and buffer the effect of stressors in space and time. The effect of groundwater on drivers and states depends on catchment characteristics, stressor combinations, scale and management practises. The proposed framework shows how groundwater in lowland catchments acts as a bridge between stressors and their effects within surface waters. It shows water managers how their management areas might be influenced by groundwater, and helps them to include this important, but often overlooked part of the water cycle in their basin management plans. The analysis of the study catchments also revealed a lack of data on the temperature of both groundwater and surface water, while it is an important parameter considering future climate warming. Copyright © 2018. Published by Elsevier B.V.

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

PubMed

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.

Evaluation of automated urban surface water extraction from Sentinel-2A imagery using different water indices

NASA Astrophysics Data System (ADS)

Yang, Xiucheng; Chen, Li

2017-04-01

Urban surface water is characterized by complex surface continents and small size of water bodies, and the mapping of urban surface water is currently a challenging task. The moderate-resolution remote sensing satellites provide effective ways of monitoring surface water. This study conducts an exploratory evaluation on the performance of the newly available Sentinel-2A multispectral instrument (MSI) imagery for detecting urban surface water. An automatic framework that integrates pixel-level threshold adjustment and object-oriented segmentation is proposed. Based on the automated workflow, different combinations of visible, near infrared, and short-wave infrared bands in Sentinel-2 image via different water indices are first compared. Results show that object-level modified normalized difference water index (MNDWI with band 11) and automated water extraction index are feasible in urban surface water mapping for Sentinel-2 MSI imagery. Moreover, comparative results are obtained utilizing optimal MNDWI from Sentinel-2 and Landsat 8 images, respectively. Consequently, Sentinel-2 MSI achieves the kappa coefficient of 0.92, compared with that of 0.83 from Landsat 8 operational land imager.

Potential Chemical Effects of Changes in the Source of Water Supply for the Albuquerque Bernalillo County Water Utility Authority

USGS Publications Warehouse

Bexfield, Laura M.; Anderholm, Scott K.

2008-01-01

Chemical modeling was used by the U.S. Geological Survey, in cooperation with the Albuquerque Bernalillo County Water Utility Authority (henceforth, Authority), to gain insight into the potential chemical effects that could occur in the Authority's water distribution system as a result of changing the source of water used for municipal and industrial supply from ground water to surface water, or to some mixture of the two sources. From historical data, representative samples of ground-water and surface-water chemistry were selected for modeling under a range of environmental conditions anticipated to be present in the distribution system. Mineral phases calculated to have the potential to precipitate from ground water were compared with the compositions of precipitate samples collected from the current water distribution system and with mineral phases calculated to have the potential to precipitate from surface water and ground-water/surface-water mixtures. Several minerals that were calculated to have the potential to precipitate from ground water in the current distribution system were identified in precipitate samples from pipes, reservoirs, and water heaters. These minerals were the calcium carbonates aragonite and calcite, and the iron oxides/hydroxides goethite, hematite, and lepidocrocite. Several other minerals that were indicated by modeling to have the potential to precipitate were not found in precipitate samples. For most of these minerals, either the kinetics of formation were known to be unfavorable under conditions present in the distribution system or the minerals typically are not formed through direct precipitation from aqueous solutions. The minerals with potential to precipitate as simulated for surface-water samples and ground-water/surface-water mixtures were quite similar to the minerals with potential to precipitate from ground-water samples. Based on the modeling results along with kinetic considerations, minerals that appear most likely to either dissolve or newly precipitate when surface water or ground-water/surface-water mixtures are delivered through the Authority's current distribution system are carbonates (particularly aragonite and calcite). Other types of minerals having the potential to dissolve or newly precipitate under conditions present throughout most of the distribution system include a form of silica, an aluminum hyroxide (gibbsite or diaspore), or the Fe-containing mineral Fe3(OH)8. Dissolution of most of these minerals (except perhaps the Fe-containing minerals) is not likely to substantially affect trace-element concentrations or aesthetic characteristics of delivered water, except perhaps hardness. Precipitation of these minerals would probably be of concern only if the quantities of material involved were large enough to clog pipes or fixtures. The mineral Fe3(OH)8 was not found in the current distribution system. Some Fe-containing minerals that were identified in the distribution system were associated with relatively high contents of selected elements, including As, Cr, Cu, Mn, Pb, and Zn. However, these Fe-containing minerals were not identified as minerals likely to dissolve when the source of water was changed from ground water to surface water or a ground-water/surface-water mixture. Based on the modeled potential for calcite precipitation and additional calculations of corrosion indices ground water, surface water, and ground-water/surface-water mixtures are not likely to differ greatly in corrosion potential. In particular, surface water and ground-water/surface-water mixtures do not appear likely to dissolve large quantities of existing calcite and expose metal surfaces in the distribution system to substantially increased corrosion. Instead, modeling calculations indicate that somewhat larger masses of material would tend to precipitate from surface water or ground-water/surface-water mixtures compared to ground water alone.

Structure and stability of pyrophyllite edge surfaces: Effect of temperature and water chemical potential

NASA Astrophysics Data System (ADS)

Kwon, Kideok D.; Newton, Aric G.

2016-10-01

The surfaces of clay minerals, which are abundant in atmospheric mineral dust, serve as an important medium to catalyze ice nucleation. The lateral edge surface of 2:1 clay minerals is postulated to be a potential site for ice nucleation. However, experimental investigations of the edge surface structure itself have been limited compared to the basal planes of clay minerals. Density functional theory (DFT) computational studies have provided insights into the pyrophyllite edge surface. Pyrophyllite is an ideal surrogate mineral for the edge surfaces of 2:1 clay minerals as it possesses no or little structural charge. Of the two most-common hydrated edge surfaces, the AC edge, (1 1 0) surface in the monoclinic polytype notation, is predicted to be more stable than the B edge, (0 1 0) surface. These stabilities, however, were determined based on the total energies calculated at 0 K and did not consider environmental effects such as temperature and humidity. In this study, atomistic thermodynamics based on periodic DFT electronic calculations was applied to examine the effects of environmental variables on the structure and thermodynamic stability of the common edge surfaces in equilibrium with bulk pyrophyllite and water vapor. We demonstrate that the temperature-dependent vibrational energy of sorbed water molecules at the edge surface is a significant component of the surface free energy and cannot be neglected when determining the surface stability of pyrophyllite. The surface free energies were calculated as a function of temperature from 240 to 600 K and water chemical potential corresponding to conditions from ultrahigh vacuum to the saturation vapor pressure of water. We show that at lower water chemical potentials (dry conditions), the AC and B edge surfaces possessed similar stabilities; at higher chemical potentials (humid conditions) the AC edge surface was more stable than the B edge surface. At high temperatures, both surfaces showed similar stabilities regardless of the water chemical potential. The equilibrium morphology of pyrophyllite crystals is also expected to be dependent on these two environmental variables. Surface defects may impact the surface reactivity. We discuss the thermodynamic stability of a possible Si cation vacancy defect which provides additional hydroxyl group on the surface.

Self-cleaning efficiency of artificial superhydrophobic surfaces.

PubMed

Bhushan, Bharat; Jung, Yong Chae; Koch, Kerstin

2009-03-03

The hierarchical structured surface of the lotus (Nelumbo nucifera, Gaertn.) leaf provides a model for the development of biomimetic self-cleaning surfaces. On these water-repellent surfaces, water droplets move easily at a low inclination of the leaf and collect dirt particles adhering to the leaf surface. Flat hydrophilic and hydrophobic, nanostructured, microstructured, and hierarchical structured superhydrophobic surfaces were fabricated, and a systematic study of wettability and adhesion properties was carried out. The influence of contact angle hysteresis on self-cleaning by water droplets was studied at different tilt angles (TA) of the specimen surfaces (3 degrees for Lotus wax, 10 degrees for n-hexatriacontane, as well as 45 degrees for both types of surfaces). At 3 degrees and 10 degrees TA, no surfaces were cleaned by moving water applied onto the surfaces with nearly zero kinetic energy, but most particles were removed from hierarchical structured surfaces, and a certain amount of particles were captured between the asperities of the micro- and hierarchical structured surfaces. After an increase of the TA to 45 degrees (larger than the tilt angles of all structured surfaces), as usually used for industrial self-cleaning tests, all nanostructured surfaces were cleaned by water droplets moving over the surfaces followed by hierarchical and microstructures. Droplets applied onto the surfaces with some pressure removed particles residues and led to self-cleaning by a combination of sliding and rolling droplets. Geometrical scale effects were responsible for superior performance of nanostructured surfaces.

Topographic design and application of hierarchical polymer surfaces replicated by microinjection compression molding

NASA Astrophysics Data System (ADS)

Guan, Wei-Sheng; Huang, Han-Xiong; Wang, Bin

2013-10-01

In recent years, the fast growing demand for biomimetic surfaces featuring unique wettability and functionality in various fields highlights the necessity of developing a reliable technique for mass production. In this work, hierarchical topography designs of templates were applied to prepare superhydrophobic surfaces via microinjection compression molding, comprehensively considering the feasibility of mechanical demolding and the superhydrophobicity and mechanical robustness of the molded polypropylene parts. Mimicking the wettability of a lotus leaf or rose petal, superhydrophobic surfaces were replicated. An unstable wetting state formed on the surface exhibiting the petal effect. On such a surface, the increased water pressure could cause water penetration into the micro gaps between the hierarchical asperities featuring low-roughness sidewalls and bottom surface; the resultant water membrane led to drastically increased water adhesion of the surface. Moreover, the low-adhesion superhydrophobicity of the molded surface was changed into superhydrophilicity, by means of introducing carbonyl groups via ultraviolet/ozone treatment and the subsequent water membrane preserved in microstructures via the pre-wetting process. Patterning the superhydrophilic micro channel on the superhydrophobic surface developed the surface microfluidic devices for micro-liter fluid pumping and mixing processes driven by surface tension.

Ions, metabolites, and cells: Water as a reporter of surface conditions during bacterial growth.

PubMed

Jarisz, Tasha A; Lane, Sarah; Gozdzialski, Lea; Hore, Dennis K

2018-06-14

Surface-specific nonlinear vibrational spectroscopy, combined with bulk solution measurements and imaging, is used to study the surface conditions during the growth of E. coli. As a result of the silica high surface charge density, the water structure at the silica-aqueous interface is known to be especially sensitive to pH and ionic strength, and surface concentration profiles develop that can be appreciably different from the bulk solution conditions. We illustrate that, in the presence of growing cells, a unique surface micro-environment is established as a result of metabolites accumulating on the silica surface. Even in the subsequent absence of the cells, this surface layer works to reduce the interfacial ionic strength as revealed by the enhanced signal from surface water molecules. In the presence of growing cells, an additional boost in surface water signal is attributed to a local pH that is higher than that of the bulk solution.

Ions, metabolites, and cells: Water as a reporter of surface conditions during bacterial growth

NASA Astrophysics Data System (ADS)

Jarisz, Tasha A.; Lane, Sarah; Gozdzialski, Lea; Hore, Dennis K.

2018-06-01

Surface-specific nonlinear vibrational spectroscopy, combined with bulk solution measurements and imaging, is used to study the surface conditions during the growth of E. coli. As a result of the silica high surface charge density, the water structure at the silica-aqueous interface is known to be especially sensitive to pH and ionic strength, and surface concentration profiles develop that can be appreciably different from the bulk solution conditions. We illustrate that, in the presence of growing cells, a unique surface micro-environment is established as a result of metabolites accumulating on the silica surface. Even in the subsequent absence of the cells, this surface layer works to reduce the interfacial ionic strength as revealed by the enhanced signal from surface water molecules. In the presence of growing cells, an additional boost in surface water signal is attributed to a local pH that is higher than that of the bulk solution.

Fabricating Superhydrophobic and Superoleophobic Surfaces with Multiscale Roughness Using Airbrush and Electrospray

NASA Astrophysics Data System (ADS)

AL-Milaji, Karam N.

Examples of superhydrophobic surfaces found in nature such as self-cleaning property of lotus leaf and walking on water ability of water strider have led to an extensive investigation in this area over the past few decades. When a water droplet rests on a textured surface, it may either form a liquid-solid-vapor composite interface by which the liquid droplet partially sits on air pockets or it may wet the surface in which the water replaces the trapped air depending on the surface roughness and the surface chemistry. Super water repellent surfaces have numerous applications in our daily life such as drag reduction, anti-icing, anti-fogging, energy conservation, noise reduction, and self-cleaning. In fact, the same concept could be applied in designing and producing surfaces that repel organic contaminations (e.g. low surface tension liquids). However, superoleophobic surfaces are more challenging to fabricate than superhydrophobic surfaces since the combination of multiscale roughness with re-entrant or overhang structure and surface chemistry must be provided. In this study, simple, cost-effective and potentially scalable techniques, i.e., airbrush and electrospray, were employed for the sake of making superhydrophobic and superoleophobic coatings with random and patterned multiscale surface roughness. Different types of silicon dioxide were utilized in this work to in order to study and to characterize the effect of surface morphology and surface roughness on surface wettability. The experimental findings indicated that super liquid repellent surfaces with high apparent contact angles and extremely low sliding angles were successfully fabricated by combining re-entrant structure, multiscale surface roughness, and low surface energy obtained from chemically treating the fabricated surfaces. In addition to that, the experimental observations regarding producing textured surfaces in mask-assisted electrospray were further validated by simulating the actual working conditions and geometries using COMSOL Multiphysics.

Permitted water use in Iowa, 1985

USGS Publications Warehouse

Runkle, D.L.; Newman, J.L.; Shields, E.M.

1985-01-01

This report summarizes where, how much and for what purpose water is allocated for use in Iowa with permits issued by the Department of Water, Air and Waste Management. In Iowa, from a total permitted water use of 855,175.45 million gallons per year, about 58 percent is from surface-water sources and about 42 percent is from ground-water sources. Streams are 80.5 percent of the total surface-water use and wells make up 80.1 percent of the total ground-water use, with 65.4 percent of ground water coming from surficial aquifers. Power generation is the use category that is permitted the largest amount of total water use, 46.6 percent, with surface water being the source of 96.7 percent and 77.9 percent of the surface water is from streams. The public water suppliers' category is the next largest use type with 15.7 percent of the total permitted water. Ground water constitutes 74.4 percent of the public water supplier category with 51.7 percent from surficial aquifers. Surface water makes up 25.6 percent of this category with 83.0 percent of the surface water withdrawn from streams. Mining comprises 13.4 percent of the total water use and is the third largest water-use category. Ground water is the source of 63.3 percent of permitted mining water use with 94.3 percent of this from quarries and sand and gravel pits. Surface water is the source of 36.7 percent of the permitted mining water use with 97.6 percent from streams. Irrigation is the fourth largest permitted use type using 12.0 percent of the total water use. Eighty-eight percent of irrigation is from ground-water sources where surficial aquifers account for 94.7 percent. Streams are 81.1 percent of irrigational surface-water use. Self-supplied industrial users are permitted 10.6 percent of the total permitted water use with 85.5 percent of this from ground-water sources and 14.5 percent from surface-water sources. Of the self-supplied industrial ground-water use, 47.9 percent comes from surficial aquifers and of the self-supplied industrial surface-water use 86.1 percent is from streams. Self-supplied commercial use is allocated 1.5 percent of the total permitted water. Surface-water is the source of 37.7 percent of this and 62.3 percent is from ground-water sources. Agricultural (non-irrigation) use is 0.3 percent of the total permitted water with 73.3 percent from groundwater sources and 26.7 percent from surface-water sources. The areas that are allocated the most water permits are east-central Iowa and west-central Iowa.

Recruiting physisorbed water in surface polymerization for bio-inspired materials of tunable hydrophobicity

DOE PAGES

Oyola-Reynoso, S.; Tevis, I. D.; Chen, J.; ...

2016-08-18

Here, chemical grafting has been widely used to modify the surface properties of materials, especially surface energy for controlled wetting, because of the resilience of such coatings/modifications. Reagents with multiple reactive sites have been used with the expectation that a monolayer will form. The step-growth polymerization mechanism, however, suggests the possibility of gel formation for hydrolyzable moieties in the presence of physisorbed water. In this report, we demonstrated that using alkyltrichlorosilanes (trivalent [i.e., 3 reactive sites]) in the surface modification of a cellulosic material (paper) does not yield a monolayer but rather gives surface-bound particles. We infer that the presencemore » of physisorbed (surface-bound) water allows for polymerization (or oligomerization) of the silane prior to its attachment on the surface. Surface energy mismatch between the hydrophobic tails of the growing polymer and any unreacted bound water leads to the assembly of the polymerizing material into spherical particles to minimize surface tension. By varying paper grammage (16.2–201.4 g m –2), we varied the accessible surface area and thus the amount of surface-adsorbed water, allowing us to control the ratio of the silane to the bound water. Using this approach, polymeric particles were formed on the surface of cellulose fibers ranging from ~70 nm to a film. The hydrophobicity of the surface, as determined by water contact angles, correlates with particle sizes (p < 0.001, Student's t-test), and, hence, the hydrophobicity can be tuned (contact angle between 94° and 149°). Using a model structure of a house, we demonstrated that as a result of this modification, paper-based houses can be rendered self-cleaning or tolerant to surface running water. In another application, we demonstrated that the felicitous choice of architectural design allows for the hydrophobic paper to be used for water harvesting.« less

Surface Water Quality-Assurance Plan for the North Florida Program Office of the U.S. Geological Survey

USGS Publications Warehouse

Franklin, Marvin A.

2000-01-01

The U.S. Geological Survey, Water Resources Division, has a policy that requires each District office to prepare a Surface Water Quality-Assurance Plan. The plan for each District describes the policies and procedures that ensure high quality in the collection, processing, analysis, computer storage, and publication of surface-water data. The North Florida Program Office Surface Water Quality-Assurance Plan documents the standards, policies, and procedures used by the North Florida Program office for activities related to the collection, processing, storage, analysis, and publication of surface-water data.

Bacterial community diversity and variation in spray water sources and the tomato fruit surface.

PubMed

Telias, Adriana; White, James R; Pahl, Donna M; Ottesen, Andrea R; Walsh, Christopher S

2011-04-21

Tomato (Solanum lycopersicum) consumption has been one of the most common causes of produce-associated salmonellosis in the United States. Contamination may originate from animal waste, insects, soil or water. Current guidelines for fresh tomato production recommend the use of potable water for applications coming in direct contact with the fruit, but due to high demand, water from other sources is frequently used. We sought to describe the overall bacterial diversity on the surface of tomato fruit and the effect of two different water sources (ground and surface water) when used for direct crop applications by generating a 454-pyrosequencing 16S rRNA dataset of these different environments. This study represents the first in depth characterization of bacterial communities in the tomato fruit surface and the water sources commonly used in commercial vegetable production. The two water sources tested had a significantly different bacterial composition. Proteobacteria was predominant in groundwater samples, whereas in the significantly more diverse surface water, abundant phyla also included Firmicutes, Actinobacteria and Verrucomicrobia. The fruit surface bacterial communities on tomatoes sprayed with both water sources could not be differentiated using various statistical methods. Both fruit surface environments had a high representation of Gammaproteobacteria, and within this class the genera Pantoea and Enterobacter were the most abundant. Despite the major differences observed in the bacterial composition of ground and surface water, the season long use of these very different water sources did not have a significant impact on the bacterial composition of the tomato fruit surface. This study has provided the first next-generation sequencing database describing the bacterial communities living in the fruit surface of a tomato crop under two different spray water regimes, and therefore represents an important step forward towards the development of science-based metrics for Good Agricultural Practices.

Impact of catchment geophysical characteristics and climate on the regional variability of dissolved organic carbon (DOC) in surface water.

PubMed

Cool, Geneviève; Lebel, Alexandre; Sadiq, Rehan; Rodriguez, Manuel J

2014-08-15

Dissolved organic carbon (DOC) is a recognized indicator of natural organic matter (NOM) in surface waters. The aim of this paper is twofold: to evaluate the impact of geophysical characteristics, climate and ecological zones on DOC concentrations in surface waters and, to develop a statistical model to estimate the regional variability of these concentrations. In this study, multilevel statistical analysis was used to achieve three specific objectives: (1) evaluate the influence of climate and geophysical characteristics on DOC concentrations in surface waters; (2) compare the influence of geophysical characteristics and ecological zones on DOC concentrations in surface waters; and (3) develop a model to estimate the most accurate DOC concentrations in surface waters. The case study involved 115 catchments from surface waters in the Province of Quebec, Canada. Results showed that mean temperatures recorded 60 days prior to sampling, total precipitation 10 days prior to sampling and percentages of wetlands, coniferous forests and mixed forests have a significant positive influence on DOC concentrations in surface waters. The catchment mean slope had a significant negative influence on DOC concentrations in surface waters. Water type (lake or river) and deciduous forest variables were not significant. The ecological zones had a significant influence on DOC concentrations. However, geophysical characteristics (wetlands, forests and slope) estimated DOC concentrations more accurately. A model describing the variability of DOC concentrations was developed and can be used, in future research, for estimating DBPs in drinking water as well evaluating the impact of climate change on the quality of surface waters and drinking water. Copyright © 2014 Elsevier B.V. All rights reserved.

Effects of electrolyzed oxidizing water on reducing Listeria monocytogenes contamination on seafood processing surfaces.

PubMed

Liu, Chengchu; Duan, Jingyun; Su, Yi-Cheng

2006-02-15

The effects of electrolyzed oxidizing (EO) water on reducing Listeria monocytogenes contamination on seafood processing surfaces were studied. Chips (5 x 5 cm(2)) of stainless steel sheet (SS), ceramic tile (CT), and floor tile (FT) with and without crabmeat residue on the surface were inoculated with L. monocytogenes and soaked in tap or EO water for 5 min. Viable cells of L. monocytogenes were detected on all chip surfaces with or without crabmeat residue after being held at room temperature for 1 h. Soaking contaminated chips in tap water resulted in small-degree reductions of the organism (0.40-0.66 log cfu/chip on clean surfaces and 0.78-1.33 log cfu/chip on dirty surfaces). Treatments of EO water significantly (p<0.05) reduced L. monocytogenes on clean surfaces (3.73 log on SS, 4.24 log on CT, and 5.12 log on FT). Presence of crabmeat residue on chip surfaces reduced the effectiveness of EO water on inactivating Listeria cells. However, treatments of EO water also resulted in significant reductions of L. monocytogenes on dirty surfaces (2.33 log on SS and CT and 1.52 log on FT) when compared with tap water treatments. The antimicrobial activity of EO water was positively correlated with its chlorine content. High oxidation-reduction potential (ORP) of EO water also contributed significantly to its antimicrobial activity against L. monocytogenes. EO water was more effective than chlorine water on inactivating L. monocytogenes on surfaces and could be used as a chlorine alternative for sanitation purpose. Application of EO water following a thorough cleaning process could greatly reduce L. monocytogenes contamination in seafood processing environments.

Planetary-scale surface water detection from space

NASA Astrophysics Data System (ADS)

Donchyts, G.; Baart, F.; Winsemius, H.; Gorelick, N.

2017-12-01

Accurate, efficient and high-resolution methods of surface water detection are needed for a better water management. Datasets on surface water extent and dynamics are crucial for a better understanding of natural and human-made processes, and as an input data for hydrological and hydraulic models. In spite of considerable progress in the harmonization of freely available satellite data, producing accurate and efficient higher-level surface water data products remains very challenging. This presentation will provide an overview of existing methods for surface water extent and change detection from multitemporal and multi-sensor satellite imagery. An algorithm to detect surface water changes from multi-temporal satellite imagery will be demonstrated as well as its open-source implementation (http://aqua-monitor.deltares.nl). This algorithm was used to estimate global surface water changes at high spatial resolution. These changes include climate change, land reclamation, reservoir construction/decommissioning, erosion/accretion, and many other. This presentation will demonstrate how open satellite data and open platforms such as Google Earth Engine have helped with this research.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oyola-Reynoso, S.; Tevis, I. D.; Chen, J.

Here, chemical grafting has been widely used to modify the surface properties of materials, especially surface energy for controlled wetting, because of the resilience of such coatings/modifications. Reagents with multiple reactive sites have been used with the expectation that a monolayer will form. The step-growth polymerization mechanism, however, suggests the possibility of gel formation for hydrolyzable moieties in the presence of physisorbed water. In this report, we demonstrated that using alkyltrichlorosilanes (trivalent [i.e., 3 reactive sites]) in the surface modification of a cellulosic material (paper) does not yield a monolayer but rather gives surface-bound particles. We infer that the presencemore » of physisorbed (surface-bound) water allows for polymerization (or oligomerization) of the silane prior to its attachment on the surface. Surface energy mismatch between the hydrophobic tails of the growing polymer and any unreacted bound water leads to the assembly of the polymerizing material into spherical particles to minimize surface tension. By varying paper grammage (16.2–201.4 g m –2), we varied the accessible surface area and thus the amount of surface-adsorbed water, allowing us to control the ratio of the silane to the bound water. Using this approach, polymeric particles were formed on the surface of cellulose fibers ranging from ~70 nm to a film. The hydrophobicity of the surface, as determined by water contact angles, correlates with particle sizes (p < 0.001, Student's t-test), and, hence, the hydrophobicity can be tuned (contact angle between 94° and 149°). Using a model structure of a house, we demonstrated that as a result of this modification, paper-based houses can be rendered self-cleaning or tolerant to surface running water. In another application, we demonstrated that the felicitous choice of architectural design allows for the hydrophobic paper to be used for water harvesting.« less

Effect of Surface Hydration on Antifouling Properties of Mixed Charged Polymers.

PubMed

Leng, Chuan; Huang, Hao; Zhang, Kexin; Hung, Hsiang-Chieh; Xu, Yao; Li, Yaoxin; Jiang, Shaoyi; Chen, Zhan

2018-05-07

Interfacial water structure on a polymer surface in water (or surface hydration) is related to the antifouling activity of the polymer. Zwitterionic polymer materials exhibit excellent antifouling activity due to their strong surface hydration. It was proposed to replace zwitterionic polymers using mixed charged polymers because it is much easier to prepare mixed charged polymer samples with much lower costs. In this study, using sum frequency generation (SFG) vibrational spectroscopy, we investigated interfacial water structures on mixed charged polymer surfaces in water, and how such structures change while exposing to salt solutions and protein solutions. The 1:1 mixed charged polymer exhibits excellent antifouling property while other mixed charged polymers with different ratios of the positive/negative charges do not. It was found that on the 1:1 mixed charged polymer surface, SFG water signal is dominated by the contribution of the strongly hydrogen bonded water molecules, indicating strong hydration of the polymer surface. The responses of the 1:1 mixed charged polymer surface to salt solutions are similar to those of zwitterionic polymers. Interestingly, exposure to high concentrations of salt solutions leads to stronger hydration of the 1:1 mixed charged polymer surface after replacing the salt solution with water. Protein molecules do not substantially perturb the interfacial water structure on the 1:1 mixed charged polymer surface and do not adsorb to the surface, showing that this mixed charged polymer is an excellent antifouling material.

Monitoring of Water and Contaminant Migration at the Groundwater-Surface Water Interface

DTIC Science & Technology

2008-08-01

seepage is occurring in a freshwater lake environment and to map the lateral extent of any subsurface contamination at the groundwater –surface water ...and Contaminant Migration at the Groundwater -Surface Water Interface August 2008 Report Documentation Page Form ApprovedOMB No. 0704-0188 Public...4. TITLE AND SUBTITLE Monitoring of Water and Contaminant Migration at the Groundwater -Surface Water Interface 5a. CONTRACT NUMBER 5b. GRANT NUMBER

Water's Interfacial Hydrogen Bonding Structure Reveals the Effective Strength of Surface-Water Interactions.

PubMed

Shin, Sucheol; Willard, Adam P

2018-06-05

We combine all-atom molecular dynamics simulations with a mean field model of interfacial hydrogen bonding to analyze the effect of surface-water interactions on the structural and energetic properties of the liquid water interface. We show that the molecular structure of water at a weakly interacting ( i.e., hydrophobic) surface is resistant to change unless the strength of surface-water interactions are above a certain threshold. We find that below this threshold water's interfacial structure is homogeneous and insensitive to the details of the disordered surface, however, above this threshold water's interfacial structure is heterogeneous. Despite this heterogeneity, we demonstrate that the equilibrium distribution of molecular orientations can be used to quantify the energetic component of the surface-water interactions that contribute specifically to modifying the interfacial hydrogen bonding network. We identify this specific energetic component as a new measure of hydrophilicity, which we refer to as the intrinsic hydropathy.

Spatio-temporal image-based parametric water surface reconstruction: a novel methodology based on refraction

NASA Astrophysics Data System (ADS)

Engelen, L.; Creëlle, S.; Schindfessel, L.; De Mulder, T.

2018-03-01

This paper presents a low-cost and easy-to-implement image-based reconstruction technique for laboratory experiments, which results in a temporal description of the water surface topography. The distortion due to refraction of a known pattern, located below the water surface, is used to fit a low parameter surface model that describes the time-dependent and three-dimensional surface variation. Instead of finding the optimal water depth for characteristic points on the surface, the deformation of the entire pattern is compared to its original shape. This avoids the need for feature tracking adopted in similar techniques, which improves the robustness to suboptimal optical conditions and small-scale, high-frequency surface perturbations. Experimental validation, by comparison with water depth measurements using a level gauge and pressure sensor, proves sub-millimetre accuracy for smooth and steady surface shapes. Although such accuracy cannot be achieved in case of highly dynamic surface phenomena, the low-frequency and large-scale free surface oscillations can still be measured with a temporal and spatial resolution mostly limited by the available optical set-up. The technique is initially intended for periodic surface phenomena, but the results presented in this paper indicate that also irregular surface shapes can robustly be reconstructed. Therefore, the presented technique is a promising tool for other research applications that require non-intrusive, low-cost surface measurements while maintaining visual access to the water below the surface. The latter ensures that the suggested surface reconstruction is compatible with simultaneous image-based velocity measurements, enabling a detailed study of the flow.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

2015-06-01

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

The differences in crown formation during the splash on the thin water layers formed on the saturated soil surface and model surface

PubMed Central

Mazur, Rafał; Polakowski, Cezary; Bieganowski, Andrzej

2017-01-01

Splash is the first stage of a negative phenomenon–soil erosion. The aim of this work was to describe the crown formation quantitatively (as part of the splash erosion) and compare the course of this phenomenon on the thin water film formed on a smooth glass surface and on the surface of saturated soil. The height of the falling water drop was 1.5 m. The observation of the crowns was carried out by high-speed cameras. The static and dynamic parameters of crown formation were analysed. It was found that the crowns formed on the water film covering the saturated soil surface were smaller and the time intervals of their existence were shorter. In addition, the shapes of the crowns were different from those created on the water layer covering the glass surface. These differences can be explained by the slightly different values of surface tension and viscosity of the soil solution, the greater roughness of the soil surface and the lower thickness of the water film on the soil surface. PMID:28750072

The differences in crown formation during the splash on the thin water layers formed on the saturated soil surface and model surface.

PubMed

Beczek, Michał; Ryżak, Magdalena; Sochan, Agata; Mazur, Rafał; Polakowski, Cezary; Bieganowski, Andrzej

2017-01-01

Splash is the first stage of a negative phenomenon-soil erosion. The aim of this work was to describe the crown formation quantitatively (as part of the splash erosion) and compare the course of this phenomenon on the thin water film formed on a smooth glass surface and on the surface of saturated soil. The height of the falling water drop was 1.5 m. The observation of the crowns was carried out by high-speed cameras. The static and dynamic parameters of crown formation were analysed. It was found that the crowns formed on the water film covering the saturated soil surface were smaller and the time intervals of their existence were shorter. In addition, the shapes of the crowns were different from those created on the water layer covering the glass surface. These differences can be explained by the slightly different values of surface tension and viscosity of the soil solution, the greater roughness of the soil surface and the lower thickness of the water film on the soil surface.

Superhydrophobicity of biological and technical surfaces under moisture condensation: stability in relation to surface structure.

PubMed

Mockenhaupt, Bernd; Ensikat, Hans-Jürgen; Spaeth, Manuel; Barthlott, Wilhelm

2008-12-02

The stability of superhydrophobic properties of eight plants and four technical surfaces in respect to water condensation has been compared. Contact and sliding angles were measured after application of water drops of ambient temperature (20 degrees C) onto cooled surfaces. Water evaporating from the drops condensed, due to the temperature difference between the drops and the surface, on the cooled samples, forming "satellite droplets" in the vicinity of the drops. Surface cooling to 15, 10, and 5 degrees C showed a gradual decrease of superhydrophobicity. The decrease was dependent on the specific surface architecture of the sample. The least decrease was found on hierarchically structured surfaces with a combination of a coarse microstructure and submicrometer-sized structures, similar to that of the Lotus leaf. Control experiments with glycerol droplets, which show no evaporation, and thus no condensation, were carried out to verify that the effects with water were caused by condensation from the drop (secondary condensation). Furthermore, the superhydrophobic properties after condensation on cooled surfaces from a humid environment for 10 min were examined. After this period, the surfaces were covered with spherical water droplets, but most samples retained their superhydrophobicity. Again, the best stability of the water-repellent properties was found on hierarchically structured surfaces similar to that of the Lotus leaf.

Effects of blending of desalinated and conventionally treated surface water on iron corrosion and its release from corroding surfaces and pre-existing scales.

PubMed

Liu, Haizhou; Schonberger, Kenneth D; Peng, Ching-Yu; Ferguson, John F; Desormeaux, Erik; Meyerhofer, Paul; Luckenbach, Heidi; Korshin, Gregory V

2013-07-01

This study examined effects of blending desalinated water with conventionally treated surface water on iron corrosion and release from corroding metal surfaces and pre-existing scales exposed to waters having varying fractions of desalinated water, alkalinities, pH values and orthophosphate levels. The presence of desalinated water resulted in markedly decreased 0.45 μm-filtered soluble iron concentrations. However, higher fractions of desalinated water in the blends were also associated with more fragile corroding surfaces, lower retention of iron oxidation products and release of larger iron particles in the bulk water. SEM, XRD and XANES data showed that in surface water, a dense layer of amorphous ferrihydrite phase predominated in the corrosion products. More crystalline surface phases developed in the presence of desalinated water. These solid phases transformed from goethite to lepidocrocite with increased fraction of desalinated water. These effects are likely to result from a combination of chemical parameters, notably variations of the concentrations of natural organic matter, calcium, chloride and sulfate when desalinated and conventionally treated waters are blended. Copyright © 2013 Elsevier Ltd. All rights reserved.

Pump station for radioactive waste water

DOEpatents

Whitton, John P.; Klos, Dean M.; Carrara, Danny T.; Minno, John J.

2003-11-18

A pump station for transferring radioactive particle containing waste water, includes: (a.) an enclosed sump having a vertically elongated right frusto conical wall surface and a bottom surface and (b.) a submersible volute centrifugal pump having a horizontally rotating impeller and a volute exterior surface. The sump interior surface, the bottom surface and the volute exterior surface are made of stainless steel having a 30 Ra or finer surface finish. A 15 Ra finish has been found to be most cost effective. The pump station is used for transferring waste water, without accumulation of radioactive fines.

Occurrence and distribution of pesticides and volatile organic compounds in ground water and surface water in Central Arizona Basins, 1996-98, and their relation to land use

USGS Publications Warehouse

Gellenbeck, Dorinda J.; Anning, David W.

2002-01-01

Samples of ground water and surface water from the Sierra Vista subbasin, the Upper Santa Cruz Basin, and the West Salt River Valley were collected and analyzed to determine the occurrence and distribution of pesticides and volatile organic compounds in central Arizona. The study was done during 1996-98 within the Central Arizona Basins study unit of the National Water-Quality Assessment program. This study included 121 wells and 4 surface-water sites in the 3 basins and the analyses of samples from 4 sites along the Santa Cruz River that were part of a separate study. Samples were collected from 121 wells and 3 surface-water sites for pesticide analyses, and samples were collected from 109 wells and 3 surface-water sites for volatile organic compound analyses. Certain pesticides detected in ground water and surface water can be related specifically to agricultural or urban uses; others can be related to multiple land uses. Effects from historical agriculture are made evident by detections of DDE in ground-water and surface-water samples collected in the West Salt River Valley and detections of atrazine and deethylatrazine in the ground water in the Upper Santa Cruz Basin. Effects from present agriculture are evident in the seasonal variability in concentrations of pre-emergent pesticides in surface-water samples from the West Salt River Valley. Several detections of DDE and dieldrin in surface water were higher than established water-quality limits. Effects of urban land use are made evident by detections of volatile organic compounds in ground water and surface water from the West Salt River Valley. Detections of volatile organic compounds in surface water from the Santa Cruz River near Nogales, Arizona, also are indications of the effects of urban land use. One detection of tetrachloroethene in ground water was higher than established water-quality limits. Water reuse is an important conservation technique in the Southwest; however, the reuse of water provides a transport mechanism for pesticides and volatile organic compounds to reach areas that are not normally affected by manmade compounds from specific land-use activities. The most complex mixture of pesticides and volatile organic compounds is in the West Salt River Valley and is the result of water-management practices and the combination of land uses in this basin throughout history.

Controlling Heterogeneous Catalysis of Water Dissociation Using Cu-Ni Bimetallic Alloy Surfaces: A Quantum Dynamics Study.

PubMed

Ray, Dhiman; Ghosh, Smita; Tiwari, Ashwani Kumar

2018-06-07

Copper-Nickel bimetallic alloys are emerging heterogeneous catalysts for water dissociation which is the rate determining step of industrially important Water Gas Shift (WGS) reaction. Yet, the detailed quantum dynamics studies of water-surface scattering in literature are limited to pure metal surfaces. We present here, a three dimensional wave-packet dynamics study of water dissociation on Cu-Ni alloy surfaces, using a pseudo diatomic model of water on a London-Eyring-Polanyi-Sato (LEPS) potential energy surface in order to study the effect of initial vibration, rotation and orientation of water molecule on reactivity. For all the chosen surfaces reactivity increases significantly with vibrational excitation. In general, for lower vibrational states the reactivity increases with increasing rotational excitation but it decreases in higher vibrational states. Molecular orientation strongly affects reactivity by helping the molecule to align along the reaction path at higher vibrational states. For different alloys, the reaction probability follows the trend of barrier heights and the surfaces having all Ni atoms in the uppermost layer are much more reactive than the ones with Cu atoms. Hence the nature of the alloy surface and initial quantum state of the incoming molecule significantly influence the reactivity in surface catalyzed water dissociation.

Dynamics of confined water reconstructed from inelastic x-ray scattering measurements of bulk response functions

NASA Astrophysics Data System (ADS)

Coridan, Robert H.; Schmidt, Nathan W.; Lai, Ghee Hwee; Abbamonte, Peter; Wong, Gerard C. L.

2012-03-01

Nanoconfined water and surface-structured water impacts a broad range of fields. For water confined between hydrophilic surfaces, measurements and simulations have shown conflicting results ranging from “liquidlike” to “solidlike” behavior, from bulklike water viscosity to viscosity orders of magnitude higher. Here, we investigate how a homogeneous fluid behaves under nanoconfinement using its bulk response function: The Green's function of water extracted from a library of S(q,ω) inelastic x-ray scattering data is used to make femtosecond movies of nanoconfined water. Between two confining surfaces, the structure undergoes drastic changes as a function of surface separation. For surface separations of ≈9 Å, although the surface-associated hydration layers are highly deformed, they are separated by a layer of bulklike water. For separations of ≈6 Å, the two surface-associated hydration layers are forced to reconstruct into a single layer that modulates between localized “frozen’ and delocalized “melted” structures due to interference of density fields. These results potentially reconcile recent conflicting experiments. Importantly, we find a different delocalized wetting regime for nanoconfined water between surfaces with high spatial frequency charge densities, where water is organized into delocalized hydration layers instead of localized hydration shells, and are strongly resistant to `freezing' down to molecular distances (<6 Å).

Studying groundwater and surface water interactions using airborne remote sensing in Heihe River basin, northwest China

NASA Astrophysics Data System (ADS)

Liu, C.; Liu, J.; Hu, Y.; Zheng, C.

2015-05-01

Managing surface water and groundwater as a unified system is important for water resource exploitation and aquatic ecosystem conservation. The unified approach to water management needs accurate characterization of surface water and groundwater interactions. Temperature is a natural tracer for identifying surface water and groundwater interactions, and the use of remote sensing techniques facilitates basin-scale temperature measurement. This study focuses on the Heihe River basin, the second largest inland river basin in the arid and semi-arid northwest of China where surface water and groundwater undergoes dynamic exchanges. The spatially continuous river-surface temperature of the midstream section of the Heihe River was obtained by using an airborne pushbroom hyperspectral thermal sensor system. By using the hot spot analysis toolkit in the ArcGIS software, abnormally cold water zones were identified as indicators of the spatial pattern of groundwater discharge to the river.

Separation of oil from bilge water I. Bilge water characteristics and the interaction of bilge water with chemically modified surfaces. Interim report, October 1994-September 1995

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang, E.L.; Calvert, J.M.; Koloski, T.

1997-02-01

We report on the results of a project using surface characterization and novel surface-modification techniques to address the issues of developing a minimally fouling ceramic membrane filter. We have studied the physical characteristics of a synthetic bilge water mixture, examined the surfaces of the ceramic filters for evidence of fouling, and identified several surface modifications that, under laboratory conditions, work well in prevention of foulants. These surfaces include hydrophobic as well as polar coatings. For the bilge water, it was discovered that detergent, at certain concentrations, may be useful in separating and coalescing oil droplets from the bilge water. Basedmore » on the results of the studies, several strategies for optimizing the removal of oil from water are suggested.« less

Potentiometric Surface of the Upper Floridan Aquifer in the St. Johns River Water Management District and Vicinity, Florida, May 2005

USGS Publications Warehouse

Kinnaman, Sandra L.

2006-01-01

INTRODUCTION This map depicts the potentiometric surface of the upper Floridan aquifer in the St. Johns River Water Management District and vicinity for May 2005. Potentiometric contours are based on water level measurements collected at 598 wens during the period May 5 - 31, near the end of the dry season. Some contours are inferred from previous potentiometric-surface maps with larger well networks. The potentiometric surface of the carbonate upper Floridan aquifer responds mainly to rainfall, and more locally, to ground water withdrawals. Potentiometric-surface highs generally correspond to topographic highs where the aquifer is recharged. Springs and areas of diffuse upward leakage naturally discharge water from the aquifer and are most prevalent along the St. Johns River. Areas of discharge are reflected by depressions in the potentiometric surface. Ground water withdrawals locally have lowered the potentiometric surface. Ground water in the upper Floridan aquifer generally flows from potentiometric highs to potentiometric lows in a direction perpendicular to the contours.

Potentiometric Surface of the Upper Floridan Aquifer in the St. Johns River Water Management District and Vicinity, Florida, May 2006

USGS Publications Warehouse

Kinnaman, Sandra L.

2006-01-01

Introduction: This map depicts the potentiometric surface of the Upper Floridan aquifer in the St. Johns River Water Management District and vicinity for May 2006. Potentiometric contours are based on water-level measurements collected at 599 wells during the period May 14-31, near the end of the dry season. Some contours are inferred from previous potentiometric-surface maps with larger well networks. The potentiometric surface of the carbonate Upper Floridan aquifer responds mainly to rainfall, and more locally, to ground-water withdrawals and springflow. Potentiometric-surface highs generally correspond to topographic highs where the aquifer is recharged. Springs and areas of diffuse upward leakage naturally discharge water from the aquifer and are most prevalent along the St. Johns River. Areas of discharge are reflected by depressions in the potentiometric surface. Ground-water withdrawals locally have lowered the potentiometric surface. Ground water in the Upper Floridan aquifer generally flows from potentiometric highs to potentiometric lows in a direction perpendicular to the contours.

Potentiometric surface of the Upper Floridan aquifer in the St. Johns River water management district and vicinity, Florida, September 2005

USGS Publications Warehouse

Kinnaman, Sandra L.

2006-01-01

This map depicts the potentiometric surface of the Upper Floridan aquifer in the St. Johns River Water Management District and vicinity for September 2005. Potentiometric contours are based on water-level measurements collected at 643 wells during the period September 12-28, near the end of the wet season. Some contours are inferred from previous potentiometric-surface maps with larger well networks. The potentiometric surface of the carbonate Upper Floridan aquifer responds mainly to rainfall, and more locally, to ground-water withdrawals and springflow. Potentiometric-surface highs generally correspond to topographic highs where the aquifer is recharged. Springs and areas of diffuse upward leakage naturally discharge water from the aquifer and are most prevalent along the St. Johns River. Areas of discharge are reflected by depressions in the potentiometric surface. Ground-water withdrawals locally have lowered the potentiometric surface. Ground water in the Upper Floridan aquifer generally flows from potentiometric highs to potentiometric lows in a direction perpendicular to the contours.

Potentiometric Surface of the Upper Floridan Aquifer in the St. Johns River Water Management District and Vicinity, Florida, September 2006

USGS Publications Warehouse

Kinnaman, Sandra L.; Dixon, Joann F.

2007-01-01

Introduction This map depicts the potentiometric surface of the Upper Floridan aquifer in the St. Johns River Water Management District and vicinity for September 2006. Potentiometric contours are based on water-level measurements collected at 571 wells during the period September 11-29, near the end of the wet season. Some contours are inferred from previouspotentiometric-surface maps with larger well networks. The potentiometric surface of the carbonate Upper Floridan aquifer responds mainly to rainfall, and more locally, to ground-water withdrawals and spring flow. Potentiometric-surface highs generally correspond to topographic highs where the aquifer is recharged. Springs and areas of diffuse upward leakage naturally discharge water from the aquifer and are most prevalent along the St. Johns River. Areas of discharge are reflected by depressions in the potentiometric surface. Ground-water withdrawals locally have lowered the potentiometric surface. Ground water in the Upper Floridan aquifer generally flows from potentiometric highs to potentiometric lows in a direction perpendicular to the contours.

Potentiometric Surface of the Upper Floridan Aquifer in the St. Johns River Water Management District and Vicinity, Florida, September 2008

USGS Publications Warehouse

Kinnaman, Sandra L.; Dixon, Joann F.

2009-01-01

This map depicts the potentiometric surface of the Upper Floridan aquifer in the St. Johns River Water Management District and vicinity for September 2008. Potentiometric contours are based on water-level measurements collected at 589 wells during the period September 15-25, near the end of the wet season. Some contours are inferred from previous potentiometric-surface maps with larger well networks. The potentiometric surface of the carbonate Upper Floridan aquifer responds mainly to rainfall, and more locally, to ground-water withdrawals and spring flow. Potentiometric-surface highs generally correspond to topographic highs where the aquifer is recharged. Springs and areas of diffuse upward leakage naturally discharge water from the aquifer and are most prevalent along the St. Johns River. Areas of discharge are reflected by depressions in the potentiometric surface. Ground-water withdrawals locally have lowered the potentiometric surface. Ground water in the Upper Floridan aquifer generally flows from potentiometric highs to potentiometric lows in a direction perpendicular to the contours.

Potentiometric Surface of the Upper Floridan Aquifer in the St. Johns River Water Management District and Vicinity, Florida, September 2007

USGS Publications Warehouse

Kinnaman, Sandra L.; Dixon, Joann F.

2008-01-01

This map depicts the potentiometric surface of the Upper Floridan aquifer in the St. Johns River Water Management District and vicinity for September 2007. Potentiometric contours are based on water-level measurements collected at 554 wells during the period September 15-27, near the end of the wet season. Some contours are inferred from previous potentiometric-surface maps with larger well networks. The potentiometric surface of the carbonate Upper Floridan aquifer responds mainly to rainfall, and more locally, to ground-water withdrawals and spring flow. Potentiometric-surface highs generally correspond to topographic highs where the aquifer is recharged. Springs and areas of diffuse upward leakage naturally discharge water from the aquifer and are most prevalent along the St. Johns River. Areas of discharge are reflected by depressions in the potentiometric surface. Ground-water withdrawals locally have lowered the potentiometric surface. Ground water in the Upper Floridan aquifer generally flows from potentiometric highs to potentiometric lows in a direction perpendicular to the contours.

Input and fate of anthropogenic estrogens and gadolinium in surface water and sewage plants in the hydrological basin of Prague (Czech Republic).

PubMed

Morteani, Giulio; Möller, Peter; Fuganti, Andrea; Paces, Tomas

2006-06-01

The concentration of the estrogens 17beta-estradiol, estriol, estrone, 17alpha-ethinylestradiol, mestranol and norethisterone and of the anthropogenic gadolinium (Gd(ant)) has been determined in the creeks and rivers, sewage treatment plants and water works of the city of Prague. The rapid degradation of estrogens in surface water allows the estrogen concentration gradient to be used as a very precise and sensitive guideline by which to pin-point sewage leaks into surface run-off water. The rather conservative behavior of Gd(ant) in surface and ground water documents in the present case the presence of sewage water in the surface water cycle.

Highly Transparent Water-Repelling Surfaces based on Biomimetic Hierarchical Structure

NASA Astrophysics Data System (ADS)

Wooh, Sanghyuk; Koh, Jai; Yoon, Hyunsik; Char, Kookheon

2013-03-01

Nature is a great source of inspiration for creating unique structures with special functions. The representative examples of water-repelling surfaces in nature, such as lotus leaves, rose petals, and insect wings, consist of an array of bumps (or long hairs) and nanoscale surface features with different dimension scales. Herein, we introduced a method of realizing multi-dimensional hierarchical structures and water-repellancy of the surfaces with different drop impact scenarios. The multi-dimensional hierarchical structures were fabricated by soft imprinting method with TiO2 nanoparticle pastes. In order to achieve the enhanced hydrophobicity, fluorinated moieties were attached to the etched surfaces to lower the surface energy. As a result, super-hydrophobic surfaces with high transparency were realized (over 176° water contact angle), and for further investigation, these hierarchical surfaces with different drop impact scenarios were characterized by varying the impact speed, drop size, and the geometry of the surfaces.

Oil Contact Angles in a Water-Decane-Silicon Dioxide System: Effects of Surface Charge

NASA Astrophysics Data System (ADS)

Xu, Shijing; Wang, Jingyao; Wu, Jiazhong; Liu, Qingjie; Sun, Chengzhen; Bai, Bofeng

2018-04-01

Oil wettability in the water-oil-rock systems is very sensitive to the evolution of surface charges on the rock surfaces induced by the adsorption of ions and other chemical agents in water flooding. Through a set of large-scale molecular dynamics simulations, we reveal the effects of surface charge on the oil contact angles in an ideal water-decane-silicon dioxide system. The results show that the contact angles of oil nano-droplets have a great dependence on the surface charges. As the surface charge density exceeds a critical value of 0.992 e/nm2, the contact angle reaches up to 78.8° and the water-wet state is very apparent. The variation of contact angles can be confirmed from the number density distributions of oil molecules. With increasing the surface charge density, the adsorption of oil molecules weakens and the contact areas between nano-droplets and silicon dioxide surface are reduced. In addition, the number density distributions, RDF distributions, and molecular orientations indicate that the oil molecules are adsorbed on the silicon dioxide surface layer-by-layer with an orientation parallel to the surface. However, the layered structure of oil molecules near the silicon dioxide surface becomes more and more obscure at higher surface charge densities.

Oil Contact Angles in a Water-Decane-Silicon Dioxide System: Effects of Surface Charge.

PubMed

Xu, Shijing; Wang, Jingyao; Wu, Jiazhong; Liu, Qingjie; Sun, Chengzhen; Bai, Bofeng

2018-04-19

Oil wettability in the water-oil-rock systems is very sensitive to the evolution of surface charges on the rock surfaces induced by the adsorption of ions and other chemical agents in water flooding. Through a set of large-scale molecular dynamics simulations, we reveal the effects of surface charge on the oil contact angles in an ideal water-decane-silicon dioxide system. The results show that the contact angles of oil nano-droplets have a great dependence on the surface charges. As the surface charge density exceeds a critical value of 0.992 e/nm 2 , the contact angle reaches up to 78.8° and the water-wet state is very apparent. The variation of contact angles can be confirmed from the number density distributions of oil molecules. With increasing the surface charge density, the adsorption of oil molecules weakens and the contact areas between nano-droplets and silicon dioxide surface are reduced. In addition, the number density distributions, RDF distributions, and molecular orientations indicate that the oil molecules are adsorbed on the silicon dioxide surface layer-by-layer with an orientation parallel to the surface. However, the layered structure of oil molecules near the silicon dioxide surface becomes more and more obscure at higher surface charge densities.

The Influence of Climate Change on Irrigated Water Demands and Surface Water Availability of the Yellow River Basin

NASA Astrophysics Data System (ADS)

Troy, T. J.; Zhang, J.

2017-12-01

Balancing irrigated water demands and surface water availability is critical for sustainable water resources management. In China, irrigation is the largest water user, and there is concern that irrigated water demands will be affected by climate change. If the relationship between climate change, irrigated water demands and surface water availability is quantified, then effective measures can be developed to maintain food production while ensuring water sustainability. This research focuses on the Yellow River, the second longest in China, and analyzes the impact of historical and projected climate change on agricultural water demands and surface water availability. Corn and wheat are selected as representative crops to estimate the effect of temperature and precipitin changes on irrigated water demands. The VIC model is used to simulate daily streamflow throughout the Yellow River, providing estimates of surface water availability. Overall, results indicate the irrigated water need and surface water availability are impacted by climate change, with spatially varying impacts depending on spatial patterns of climate trends and river network position. This research provides insight into water security in the Yellow River basin, indicating where water efficiency measures are needed and where they are not.

Vicariance biogeography of the open-ocean Pacific

NASA Astrophysics Data System (ADS)

White, Brian N.

The first cladogram to treat oceanic water masses as distinct geographic units presents a ‘hydrotectonic’ history of Pacific surface water masses. It is used to test the idea that the oceanographic subdivision of the surface waters of the Pacific Basin into separate water masses shaped pelagic biogeographic patterns in much the same way that the tectonic fragmentation of Pangea influenced biogeographic patterns on land. The historical water-mass relationships depicted by the surface water-mass cladogram resemble modern pelagic biogeographic regions. The prediction that the cladistic phylogenies of monophyletic groups having allopatric taxa in three or more surface water masses will be consistent with the topology of the surface water-mass cladogram is met by the pelagic fish genera Stomias and Evermanella.

Anomalous water dynamics at surfaces and interfaces: synergistic effects of confinement and surface interactions

NASA Astrophysics Data System (ADS)

Biswas, Rajib; Bagchi, Biman

2018-01-01

In nature, water is often found in contact with surfaces that are extended on the scale of molecule size but small on a macroscopic scale. Examples include lipid bilayers and reverse micelles as well as biomolecules like proteins, DNA and zeolites, to name a few. While the presence of surfaces and interfaces interrupts the continuous hydrogen bond network of liquid water, confinement on a mesoscopic scale introduces new features. Even when extended on a molecular scale, natural and biological surfaces often have features (like charge, hydrophobicity) that vary on the scale of the molecular diameter of water. As a result, many new and exotic features, which are not seen in the bulk, appear in the dynamics of water close to the surface. These different behaviors bear the signature of both water-surface interactions and of confinement. In other words, the altered properties are the result of the synergistic effects of surface-water interactions and confinement. Ultrafast spectroscopy, theoretical modeling and computer simulations together form powerful synergistic approaches towards an understanding of the properties of confined water in such systems as nanocavities, reverse micelles (RMs), water inside and outside biomolecules like proteins and DNA, and also between two hydrophobic walls. We shall review the experimental results and place them in the context of theory and simulations. For water confined within RMs, we discuss the possible interference effects propagating from opposite surfaces. Similar interference is found to give rise to an effective attractive force between two hydrophobic surfaces immersed and kept fixed at a separation of d, with the force showing an exponential dependence on this distance. For protein and DNA hydration, we shall examine a multitude of timescales that arise from frustration effects due to the inherent heterogeneity of these surfaces. We pay particular attention to the role of orientational correlations and modification of the same due to interaction with the surfaces.

Effects of surface topography and vibrations on wetting: Superhydrophobicity, icephobicity and corrosion resistance

NASA Astrophysics Data System (ADS)

Ramachandran, Rahul

Concrete and metallic materials are widely used in construction and water industry. The interaction of both these materials with water and ice (or snow) produces undesirable results and is therefore of interest. Water that gets absorbed into the pores of dry concrete expands on freezing and can lead to crack formation. Also, the ice accretion on concrete surfaces such as roadways can have disastrous consequence. Metallic components used in the water industry undergo corrosion due to contact with aqueous corrosive solutions. Therefore, it is desirable to make concrete water/ice-repellent, and to make metallic surfaces corrosion-resistant. Recent advances in micro/nanotechnology have made it possible to design functional micro/nanostructured surfaces with micro/nanotopography providing low adhesion. Some examples of such surfaces are superhydrophobic surfaces, which are extremely water repellent, and icephobic surfaces, which have low ice adhesion, repel incoming water droplets before freezing, or delay ice nucleation. This dissertation investigates the effects of surface micro/nanotopography and small amplitude fast vibrations on the wetting and adhesion of concrete with the goal of producing hydrophobic and icephobic concrete, and on the wetting of metallic surfaces to prevent corrosion. The relationship between surface micro/nanotopography and small fast vibrations is established using the method of separation of motions. Both these small scale effects can be substituted by an effective force or energy. The structure-property relationships in materials and surfaces are established. Both vibrations as well as surface micro/nanopatterns can affect wetting properties such as contact angle and surface free energy. Hydrophobic engineered cementitious composite samples are produced by controlling their surface topography and surface free energy. The surface topography is controlled by varying the concrete mixture composition. The surface free energy of concrete is lowered using a hydrophobic emulsion. The hydrophobic concrete samples were able to repel incoming water droplets as well as resist droplet pinning. Corrosion resistance is achieved in cast iron samples by rendering them superhydrophobic. The corrosion resistance of superhydrophobic surfaces with micro/nanotopography may be explained by the low effective contact area with the electrolyte. The experimental results matched the theoretical predictions based on surface roughness and wettability. The icephobicity of engineered cementitious composite samples is achieved by hydrophobization, by using coatings containing dielectric material (such as polyvinyl alcohol fibers), and by controlling the surface topography. Two aspects of the icephobicity of concrete, namely, the repulsion of incoming water droplets before freezing and the ice adhesion strength, are investigated experimentally. It is found that icephobic performance of concrete depends on these parameters --- the hydrophobic emulsion concentration, the polyvinyl alcohol fiber content, the water to cement ratio, and the sand to cement ratio. The potential for biomimetic icephobicity of thermogenic skunk cabbage plant is investigated, and it is found that the surface topography of its leaves can affect the heat transfer from the plant to the surrounding snow. The hierarchical microstructure of the leaf surface coupled with its high adhesion to water suggests the presence of an impregnated wetting state, which can minimize the heat loss. Thus functional materials and surfaces, such as hydrophobic and icephobic engineered cementitious composites and corrosion resistant metallic surfaces, can be produced by controlling the surface micro/nanotopography.

Ground-water situation in Oregon

USGS Publications Warehouse

Newcomb, R.C.

1951-01-01

The water that occurs beneath the land surface follows definite and well-known rules of hydraulics, the same as water on the surface. However, ground water must be studied by methods, some of which are unique to that type of water occurrence, in order to evaluate the part it plays in the over-all water scheme.Water that falls on the land surface as rain or snow and water that rests upon the surface may in places pass laterally or downward through the pores of the earth materials. There it may take one or more of a variety of paths before again flowing out on the surface or being expelled to the atmosphere by evaporation and by the transpiration of plants. Water so diverted underground is delayed or diverted from its course toward the sea and that digression results in many services of prime importance to mankind. Underground, the water generally exceeds in total quantity the water present on the land surface at any one time.The discussion of ground water can be clarified somewhat by a description of the major parts or phases of the normal path of water underground.

An energy balance model exploration of the impacts of interactions between surface albedo, cloud cover and water vapor on polar amplification

NASA Astrophysics Data System (ADS)

Södergren, A. Helena; McDonald, Adrian J.; Bodeker, Gregory E.

2017-11-01

We examine the effects of non-linear interactions between surface albedo, water vapor and cloud cover (referred to as climate variables) on amplified warming of the polar regions, using a new energy balance model. Our simulations show that the sum of the contributions to surface temperature changes due to any variable considered in isolation is smaller than the temperature changes from coupled feedback simulations. This non-linearity is strongest when all three climate variables are allowed to interact. Surface albedo appears to be the strongest driver of this non-linear behavior, followed by water vapor and clouds. This is because increases in longwave radiation absorbed by the surface, related to increases in water vapor and clouds, and increases in surface absorbed shortwave radiation caused by a decrease in surface albedo, amplify each other. Furthermore, our results corroborate previous findings that while increases in cloud cover and water vapor, along with the greenhouse effect itself, warm the polar regions, water vapor also significantly warms equatorial regions, which reduces polar amplification. Changes in surface albedo drive large changes in absorption of incoming shortwave radiation, thereby enhancing surface warming. Unlike high latitudes, surface albedo change at low latitudes are more constrained. Interactions between surface albedo, water vapor and clouds drive larger increases in temperatures in the polar regions compared to low latitudes. This is in spite of the fact that, due to a forcing, cloud cover increases at high latitudes and decreases in low latitudes, and that water vapor significantly enhances warming at low latitudes.

Giardia spp. Are Commonly Found in Mixed Assemblages in Surface Water, as Revealed by Molecular and Whole-Genome Characterization

PubMed Central

Tsui, Clement K.-M.; Hsiao, William W. L.; Uyaguari-Diaz, Miguel I.; Ho, Jordan; Tang, Patrick; Isaac-Renton, Judith

2015-01-01

Giardia is the most common parasitic cause of gastrointestinal infections worldwide, with transmission through surface water playing an important role in various parts of the world. Giardia duodenalis (synonyms: G. intestinalis and G. lamblia), a multispecies complex, has two zoonotic subtypes, assemblages A and B. When British Columbia (BC), a western Canadian province, experienced several waterborne giardiasis outbreaks due to unfiltered surface drinking water in the late 1980s, collection of isolates from surface water, as well as from humans and beavers (Castor canadensis), throughout the province was carried out. To better understand Giardia in surface water, 71 isolates, including 29 from raw surface water samples, 29 from human giardiasis cases, and 13 from beavers in watersheds from this historical library were characterized by PCR. Study isolates also included isolates from waterborne giardiasis outbreaks. Both assemblages A and B were identified in surface water, human, and beavers samples, including a mixture of both assemblages A and B in waterborne outbreaks. PCR results were confirmed by whole-genome sequencing (WGS) for one waterborne outbreak and supported the clustering of human, water, and beaver isolates within both assemblages. We concluded that contamination of surface water by Giardia is complex, that the majority of our surface water isolates were assemblage B, and that both assemblages A and B may cause waterborne outbreaks. The higher-resolution data provided by WGS warrants further study to better understand the spread of Giardia. PMID:25956776

An ontology design pattern for surface water features

USGS Publications Warehouse

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

2014-01-01

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

Molecular dynamics simulations study of nano bubble attachment at hydrophobic surfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

Bubble attachment phenomena are examined using Molecular Dynamics Simulations (MDS) for the first time. The simulation involves a nitrogen nano bubble containing 906 nitrogen molecules in a water phase with 74,000 water molecules at molybdenite surfaces. During a simulation period of 1 ns, film rupture and displacement occurs. The attached nanobubble at the hydrophobic molybdenite face surface results in a contact angle of about 90º. This spontaneous attachment is due to a “water exclusion zone” at the molybdenite face surface and can be explained by a van der Waals (vdW) attractive force, as discussed in the literature. In contrast, themore » film is stable at the hydrophilic quartz (001) surface and the bubble does not attach. Contact angles determined from MD simulations are reported, and these results agree well with experimental and MDS sessile drop results. In this way, film stability and bubble attachment are described with respect to interfacial water structure for surfaces of different polarity. Interfacial water molecules at the hydrophobic molybdenite face surface have relatively weak interactions with the surface when compared to the hydrophilic quartz (001) surface, as revealed by the presence of a 3 Å “water exclusion zone” at the molybdenite/water interface. The molybdenite armchair-edge and zigzag-edge surfaces show a comparably slow process for film rupture and displacement when compared to the molybdenite face surface, which is consistent with their relatively weak hydrophobic character.« less

Engineering tunable bio-inspired polymeric coatings for amphiphobic fibrous materials

NASA Astrophysics Data System (ADS)

Oyola-Reynoso, Stephanie

Chemical grafting has been widely used to modify the surface properties of materials, especially surface energy for controlled wetting, because of the resilience of such coatings/modifications. Reagents with multiple reactive sites have been used with the expectation that a monolayer will form. The step-growth polymerization mechanism, however, suggests the possibility of gel formation for hydrolysable moieties in the presence of physisorbed water. In the following chapters, we demonstrate that using alkyltrichlorosilanes (trivalent [3 reactive sites]) in the surface modification of a cellulosic material (paper) does not yield a monolayer but rather gives surface-bound polymeric particles. We infer that the presence of physisorbed (surface-bound) water allows for polymerization (or oligomerization) of the silane, prior to its attachment on the surface. Surface energy mismatch between the hydrophobic tails of the growing polymer and any unreacted bound water leads to the assembly of the polymerizing material into spherical particles to minimize surface tension. By varying paper grammage (16.2-201.4 g/m2), we varied the accessible surface area and thus the amount of surface-adsorbed water, allowing us to control the ratio of the silane to the bound water. Using this approach, polymeric particles were formed on the surface of cellulose fibers ranging from 70 nm to a film. The hydrophobicity of the surface, as determined by water contact angles, correlates with particle sizes (p < 0.001, Student t-test), and, hence, the hydrophobicity can be tuned (contact angle between 94° and 149°). Using a model structure of a house, we demonstrated that as a result of this modification, cardboard houses can be rendered self-cleaning or tolerant to surface running water. Each of the chapters below supports the mechanism via a series of applications, material characterization, and/or, smart engineering.

Evaluation of surface water resources from machine-processing of ERTS multispectral data

NASA Technical Reports Server (NTRS)

Mausel, P. W.; Todd, W. J.; Baumgardner, M. F.; Mitchell, R. A.; Cook, J. P.

1976-01-01

The surface water resources of a large metropolitan area, Marion County (Indianapolis), Indiana, are studied in order to assess the potential value of ERTS spectral analysis to water resources problems. The results of the research indicate that all surface water bodies over 0.5 ha were identified accurately from ERTS multispectral analysis. Five distinct classes of water were identified and correlated with parameters which included: degree of water siltiness; depth of water; presence of macro and micro biotic forms in the water; and presence of various chemical concentrations in the water. The machine processing of ERTS spectral data used alone or in conjunction with conventional sources of hydrological information can lead to the monitoring of area of surface water bodies; estimated volume of selected surface water bodies; differences in degree of silt and clay suspended in water and degree of water eutrophication related to chemical concentrations.

Super Water-Repellent Fractal Surfaces of a Photochromic Diarylethene Induced by UV Light

NASA Astrophysics Data System (ADS)

Izumi, Norikazu; Minami, Takayuki; Mayama, Hiroyuki; Takata, Atsushi; Nakamura, Shinichiro; Yokojima, Satoshi; Tsujii, Kaoru; Uchida, Kingo

2008-09-01

Photochromic diarylethene forms super water-repellent surfaces upon irradiation with UV light. Microfibril-like crystals grow on the solid diarylethene surface after UV irradiation, and the contact angle of water on the surface becomes larger with increasing surface roughness with time. The fractal analysis was made by the box-counting method for the rough surfaces. There are three regions in the roughness size having the fractal dimension of ca. 2.4 (size of roughness smaller than 5 µm), of ca. 2.2 (size of roughness between 5-40 µm), and of ca. 2.0 (size of roughness larger than 40 µm). The fractal dimension of ca. 2.4 was due to the fibril-like structures generated gradually by UV irradiation on diarylethene surfaces accompanied with an increase in the contact angle. The surface structure with larger fractal dimension mainly contributes to realizing the super water-repellency of the diarylethene surfaces. This mechanism of spontaneous formation of fractal surfaces is similar to that for triglyceride and alkylketene dimer waxes.

Icephobicity and the effect of water condensation on the superhydrophobic low-density polyethylene surface

NASA Astrophysics Data System (ADS)

Yuan, Zhiqing; Wang, Menglei; Huang, Juan; Wang, Xian; Bin, Jiping; Peng, Chaoyi; Xing, Suli; Xiao, Jiayu; Zeng, Jingcheng; Xiao, Ximei; Fu, Xin; Gong, Huifang; Zhao, Dejian; Chen, Hong

2015-06-01

A superhydrophobic surface was obtained on a low-density polyethylene (LDPE) substrate using a facile method. The water contact angle and the sliding angle of the superhydrophobic LDPE surface were 155 ± 2° and 4°, respectively. The ice shear stress of the superhydrophobic LDPE surface was 2.08 times smaller than that of the flat LDPE surface. The superhydrophobic surface still showed excellent icephobicity and superhydrophobicity after undergoing a circulatory icing/deicing procedure five times. In addition, water condensation and its effect on the icephobicity of the as-prepared superhydrophobic surface were also studied.

Laser surface texturing of 316L stainless steel in air and water: A method for increasing hydrophilicity via direct creation of microstructures

NASA Astrophysics Data System (ADS)

Razi, Sepehr; Madanipour, Khosro; Mollabashi, Mahmoud

2016-06-01

Laser processing of materials in water contact is sometimes employed for improving the machining, cutting or welding quality. Here, we demonstrate surface patterning of stainless steel grade 316L by nano-second laser processing in air and water. Suitable adjustments of laser parameters offer a variety of surface patterns on the treated targets. Furthermore alterations of different surface features such as surface chemistry and wettability are investigated in various processing circumstances. More than surface morphology, remarkable differences are observed in the surface oxygen content and wettability of the samples treated in air and water at the same laser processing conditions. Mechanisms of the changes are discussed extensively.

Modeling surface-water flow and sediment mobility with the Multi-Dimensional Surface-Water Modeling System (MD_SWMS)

USGS Publications Warehouse

McDonald, Richard; Nelson, Jonathan; Kinzel, Paul; Conaway, Jeffrey S.

2006-01-01

The Multi-Dimensional Surface-Water Modeling System (MD_SWMS) is a Graphical User Interface for surface-water flow and sediment-transport models. The capabilities of MD_SWMS for developing models include: importing raw topography and other ancillary data; building the numerical grid and defining initial and boundary conditions; running simulations; visualizing results; and comparing results with measured data.

Water-Use Estimates for West Virginia, 2004

USGS Publications Warehouse

Atkins, John T.

2007-01-01

This study estimates the quantity of surface water and ground water used within West Virginia. About 4,787 million gallons per day (Mgal/d) of water were withdrawn from West Virginia surface-water and ground-water sources in 2004, with about 4,641 Mgal/d (97 percent) from surface-water sources and about 146 Mgal/d (3 percent) from ground water sources. The largest surface-water withdrawals were in Grant and Mason Counties and were about 1,156 and 1,090 Mgal/d, respectively. The largest ground-water withdrawals were in Berkeley and Wood Counties and were about 12.0 and 12.8 Mgal/d, respectively. Estimates were determined for surface-water and ground-water withdrawals in seven water-use categories: public supply, domestic, thermoelectric power, industrial, irrigation, commercial, and mining. Instream water uses, including hydroelectric power generation, were not considered. Total withdrawals for public supply were 189 Mgal/d, of which 152 Mgal/d were from surface-water sources and 37 Mgal/d were from ground-water sources. Kanawha County withdrew 34 Mgal/d of surface water for public supply, which is more than any other county in the state. Wood County withdrew more ground water for public supply than any other county in the state, about 7.59 Mgal/d. The total domestic (non-publicly supplied) water withdrawal was estimated at 33.5 Mgal/d, with 98 percent from ground water and 2 percent from surface water. There were 17 fossil-fuel, steam-generating thermoelectric power plants operated in the state, 10 plants with once-through cooling systems and 7 plants with recirculation cooling systems. Thermoelectric power used the greatest amount of water compared to the other water-use categories, and water withdrawal from surface-water sources was about 3,406 Mgal/d for plants with once-through cooling systems and about 145 Mgal/d for plants with recirculation cooling systems. Only a trace of water was withdrawn from ground-water sources for plants with once-through cooling systems and about 0.20 Mgal/d for plants with recirculation cooling systems. Water withdrawal by industries was about 911 Mgal/d from surface-water sources and about 54 Mgal/d from ground-water sources. West Virginia had the lowest estimated irrigation of any state or territory of the United States, with only about 0.036 Mgal/d withdrawn from surface-water sources and 0.036 Mgal/d withdrawn from ground-water sources. Water withdrawal for commercial use was about 16.7 Mgal/d from surface-water sources and about 16.0 Mgal/d from ground-water sources. Water withdrawal for mining was about 9.78 Mgal/d from surface-water sources and about 4.89 Mgal/d from ground-water sources. The proportions of surface-water and ground-water withdrawals were similar in 1995 and 2004 (at about 3 percent ground water). Public-supply withdrawal for 2004 was about the same as for 2000 and 7 percent greater than the 1995 estimate. Domestic withdrawal for 2004 was about 18 percent less than the 1995 estimate. Withdrawal for thermoelectric power for 2004 was about 10 percent less than the 2000 estimate and about 18 percent greater than the 1995 estimate. Industrial withdrawal for 2004 was about 27 percent less than the estimate for 1995 and about the same as the estimate for 2000. Irrigation withdrawal for 2004 was about double that estimated for 2000. Commercial withdrawal for 2004 was down 28 percent from 1995. Mining withdrawals for 2004 were about 31 and 32 percent greater for surface and ground water, respectively, than estimates for 1995.

Water adsorption on the P-rich GaP(100) surface: optical spectroscopy from first principles

NASA Astrophysics Data System (ADS)

May, Matthias M.; Sprik, Michiel

2018-03-01

The contact of water with semiconductors typically changes its surface electronic structure by oxidation or corrosion processes. A detailed knowledge—or even control of—the surface structure is highly desirable, as it impacts the performance of opto-electronic devices from gas-sensing to energy conversion applications. It is also a prerequisite for density functional theory-based modelling of the electronic structure in contact with an electrolyte. The P-rich GaP(100) surface is extraordinary with respect to its contact with gas-phase water, as it undergoes a surface reordering, but does not oxidise. We investigate the underlying changes of the surface in contact with water by means of theoretically derived reflection anisotropy spectroscopy (RAS). A comparison of our results with experiment reveals that a water-induced hydrogen-rich phase on the surface is compatible with the boundary conditions from experiment, reproducing the optical spectra. We discuss potential reaction paths that comprise a water-enhanced hydrogen mobility on the surface. Our results also show that computational RAS—required for the interpretation of experimental signatures—is feasible for GaP in contact with water double layers. Here, RAS is sensitive to surface electric fields, which are an important ingredient of the Helmholtz-layer. This paves the way for future investigations of RAS at the semiconductor–electrolyte interface.

Modifying the anti-wetting property of butterfly wings and water strider legs by atomic layer deposition coating: surface materials versus geometry.

PubMed

Ding, Yong; Xu, Sheng; Zhang, Yue; Wang, Aurelia C; Wang, Melissa H; Xiu, Yonghao; Wong, Ching Ping; Wang, Zhong Lin

2008-09-03

Although butterfly wings and water strider legs have an anti-wetting property, their working conditions are quite different. Water striders, for example, live in a wet environment and their legs need to support their weight and bear the high pressure during motion. In this work, we have focused on the importance of the surface geometrical structures in determining their performance. We have applied an atomic layer deposition technique to coat the surfaces of both butterfly wings and water strider legs with a uniform 30 nm thick hydrophilic Al(2)O(3) film. By keeping the surface material the same, we have studied the effect of different surface roughness/structure on their hydrophobic property. After the surface coating, the butterfly wings changed to become hydrophilic, while the water strider legs still remained super-hydrophobic. We suggest that the super-hydrophobic property of the water strider is due to the special shape of the long inclining spindly cone-shaped setae at the surface. The roughness in the surface can enhance the natural tendency to be hydrophobic or hydrophilic, while the roughness in the normal direction of the surface is favorable for forming a composite interface.

A GPU-based mipmapping method for water surface visualization

NASA Astrophysics Data System (ADS)

Li, Hua; Quan, Wei; Xu, Chao; Wu, Yan

2018-03-01

Visualization of water surface is a hot topic in computer graphics. In this paper, we presented a fast method to generate wide range of water surface with good image quality both near and far from the viewpoint. This method utilized uniform mesh and Fractal Perlin noise to model water surface. Mipmapping technology was enforced to the surface textures, which adjust the resolution with respect to the distance from the viewpoint and reduce the computing cost. Lighting effect was computed based on shadow mapping technology, Snell's law and Fresnel term. The render pipeline utilizes a CPU-GPU shared memory structure, which improves the rendering efficiency. Experiment results show that our approach visualizes water surface with good image quality at real-time frame rates performance.

Occurrence of Diatoms in Lakeside Wells in Northern New Jersey as an Indicator of the Effect of Surface Water on Ground-Water Quality

USGS Publications Warehouse

Reilly, Timothy J.; Walker, Christopher E.; Baehr, Arthur L.; Schrock, Robin M.; Reinfelder, John R.

2006-01-01

In a novel approach for detecting ground-water/surface-water interaction, diatoms were used as an indicator that surface water affects ground-water quality in lakeside communities in northern New Jersey. The presence of diatoms, which are abundant in lakes, in adjacent domestic wells demonstrated that ground water in these lakeside communities was under the direct influence of surface water. Entire diatom frustules were present in 17 of 18 water samples collected in August 1999 from domestic wells in communities surrounding Cranberry Lake and Lake Lackawanna. Diatoms in water from the wells were of the same genus as those found in the lakes. The presence of diatoms in the wells, together with the fact that most static and stressed water levels in wells were below the elevation of the lake surfaces, indicates that ground-water/surface-water interaction is likely. Ground-water/surface-water interaction also probably accounts for the previously documented near-ubiquitous presence of methyl tertiary-butyl ether in the ground-water samples. Recreational use of lakes for motor boating and swimming, the application of herbicides for aquatic weed control, runoff from septic systems and roadways, and the presence of waterfowl all introduce contaminants to the lake. Samples from 4 of the 18 wells contained Navicula spp., a documented significant predictor of Giardia and Cryptosporidium. Because private well owners in New Jersey generally are not required to regularly monitor their wells, and tests conducted by public-water suppliers may not be sensitive to indicators of ground-water/surface-water interaction, these contaminants may remain undetected. The presence of diatoms in wells in similar settings can warn of lake/well interactions in the absence of other indicators.

Presence of active pharmaceutical ingredients in the continuum of surface and ground water used in drinking water production.

PubMed

Ahkola, Heidi; Tuominen, Sirkku; Karlsson, Sanja; Perkola, Noora; Huttula, Timo; Saraperä, Sami; Artimo, Aki; Korpiharju, Taina; Äystö, Lauri; Fjäder, Päivi; Assmuth, Timo; Rosendahl, Kirsi; Nysten, Taina

2017-12-01

Anthropogenic chemicals in surface water and groundwater cause concern especially when the water is used in drinking water production. Due to their continuous release or spill-over at waste water treatment plants, active pharmaceutical ingredients (APIs) are constantly present in aquatic environment and despite their low concentrations, APIs can still cause effects on the organisms. In the present study, Chemcatcher passive sampling was applied in surface water, surface water intake site, and groundwater observation wells to estimate whether the selected APIs are able to end up in drinking water supply through an artificial groundwater recharge system. The API concentrations measured in conventional wastewater, surface water, and groundwater grab samples were assessed with the results obtained with passive samplers. Out of the 25 APIs studied with passive sampling, four were observed in groundwater and 21 in surface water. This suggests that many anthropogenic APIs released to waste water proceed downstream and can be detectable in groundwater recharge. Chemcatcher passive samplers have previously been used in monitoring several harmful chemicals in surface and wastewaters, but the path of chemicals to groundwater has not been studied. This study provides novel information on the suitability of the Chemcatcher passive samplers for detecting APIs in groundwater wells.

Water vapor adsorption on goethite.

PubMed

Song, Xiaowei; Boily, Jean-François

2013-07-02

Goethite (α-FeOOH) is an important mineral contributing to processes of atmospheric and terrestrial importance. Their interactions with water vapor are particularly relevant in these contexts. In this work, molecular details of water vapor (0.0-19.0 Torr; 0-96% relative humidity at 25 °C) adsorption at surfaces of synthetic goethite nanoparticles reacted with and without HCl and NaCl were resolved using vibrational spectroscopy. This technique probed interactions between surface (hydr)oxo groups and liquid water-like films. Molecular dynamics showed that structures and orientations adopted by these waters are comparable to those adopted at the interface with liquid water. Particle surfaces reacted with HCl accumulated less water than acid-free surfaces due to disruptions in hydrogen bond networks by chemisorbed waters and chloride. Particles reacted with NaCl had lower loadings below ∼10 Torr water vapor but greater loadings above this value than salt-free surfaces. Water adsorption reactions were here affected by competitive hydration of coexisting salt-free surface regions, adsorbed chloride and sodium, as well as precipitated NaCl. Collectively, the findings presented in this study add further insight into the initial mechanisms of thin water film formation at goethite surfaces subjected to variations in water vapor pressure that are relevant to natural systems.

Hydrologic effects of impoundments in Sherburne National Wildlife Refuge, Minnesota

USGS Publications Warehouse

Brown, R.G.

1984-01-01

The hydrologic effects of proposed impoundments in Sherburne National Wildlife Refuge were found to be insignificant with respect to both ground- and surface-water flow patterns and water quality. Monitoring of water levels in 23 observation wells and of discharge in the St. Francis River during 1980 and 1981 has shown that ground water in the surf icial aquifer responds quickly to areal recharge and subsequently discharges to the St. Francis River. The impoundment of surface water in the refuge was not found to affect water levels in the refuge significantly. The impoundments may affect ground-water-flow systems beneath and adjacent to the impoundments. Quality of ground and surface water was found to be similar except ground water contained higher concentrations of dissolved nitrite plus nitrate nitrogen than surface water. Phytoplankton removed dissolved nitrite plus nitrate nitrogen from surface water. The effects of impoundments on water quality are expected to be minor.

Patterns and drivers for wetland connections in the Prairie Pothole Region, United States

USGS Publications Warehouse

Vanderhoof, Melanie; Christensen, Jay R.; Alexander, Laurie C.

2017-01-01

Ecosystem function in rivers, lakes and coastal waters depends on the functioning of upstream aquatic ecosystems, necessitating an improved understanding of watershed-scale interactions including variable surface-water flows between wetlands and streams. As surface water in the Prairie Pothole Region expands in wet years, surface-water connections occur between many depressional wetlands and streams. Minimal research has explored the spatial patterns and drivers for the abundance of these connections, despite their potential to inform resource management and regulatory programs including the U.S. Clean Water Act. In this study, wetlands were identified that did not intersect the stream network, but were shown with Landsat images (1990–2011) to become merged with the stream network as surface water expanded. Wetlands were found to spill into or consolidate with other wetlands within both small (2–10 wetlands) and large (>100 wetlands) wetland clusters, eventually intersecting a stream channel, most often via a riparian wetland. These surface-water connections occurred over a wide range of wetland distances from streams (averaging 90–1400 m in different ecoregions). Differences in the spatial abundance of wetlands that show a variable surface-water connection to a stream were best explained by smaller wetland-to-wetland distances, greater wetland abundance, and maximum surface-water extent. This analysis demonstrated that wetland arrangement and surface water expansion are important mechanisms for depressional wetlands to connect to streams and provides a first step to understanding the frequency and abundance of these surface-water connections across the Prairie Pothole Region.

Microbial and chemical contamination during and after flooding in the Ohio River-Kentucky, 2011.

PubMed

Yard, Ellen E; Murphy, Matthew W; Schneeberger, Chandra; Narayanan, Jothikumar; Hoo, Elizabeth; Freiman, Alexander; Lewis, Lauren S; Hill, Vincent R

2014-09-19

Surface water contaminants in Kentucky during and after 2011 flooding were characterized. Surface water samples were collected during flood stage (May 2-4, 2011; n = 15) and after (July 25-26, 2011; n = 8) from four different cities along the Ohio River and were analyzed for the presence of microbial indicators, pathogens, metals, and chemical contaminants. Contaminant concentrations during and after flooding were compared using linear and logistic regression. Surface water samples collected during flooding had higher levels of E. coli, enterococci, Salmonella, Campylobacter, E. coli O157:H7, adenovirus, arsenic, copper, iron, lead, and zinc compared to surface water samples collected 3-months post-flood (P < 0.05). These results suggest that flooding increases microbial and chemical loads in surface water. These findings reinforce commonly recommended guidelines to limit exposure to flood water and to appropriately sanitize contaminated surfaces and drinking wells after contamination by flood water.

Microbial and chemical contamination during and after flooding in the Ohio River—Kentucky, 2011

PubMed Central

Yard, Ellen E.; Murphy, Matthew W.; Schneeberger, Chandra; Narayanan, Jothikumar; Hoo, Elizabeth; Freiman, Alexander; Lewis, Lauren S.; Hill, Vincent R.

2017-01-01

Surface water contaminants in Kentucky during and after 2011 flooding were characterized. Surface water samples were collected during flood stage (May 2–4, 2011; n = 15) and after (July 25–26, 2011; n = 8) from four different cities along the Ohio River and were analyzed for the presence of microbial indicators, pathogens, metals, and chemical contaminants. Contaminant concentrations during and after flooding were compared using linear and logistic regression. Surface water samples collected during flooding had higher levels of E. coli, enterococci, Salmonella, Campylobacter, E. coli O157:H7, adenovirus, arsenic, copper, iron, lead, and zinc compared to surface water samples collected 3-months post-flood (P < 0.05). These results suggest that flooding increases microbial and chemical loads in surface water. These findings reinforce commonly recommended guidelines to limit exposure to flood water and to appropriately sanitize contaminated surfaces and drinking wells after contamination by flood water. PMID:24967556

Quality of water and chemistry of bottom sediment in the Rillito Creek basin, Tucson, Arizona, 1986-92

USGS Publications Warehouse

Tadayon, Saeid; Smith, C.F.

1994-01-01

Data were collected on physical properties and chemistry of 4 surface water, l4 ground water, and 4 bottom sediment sites in the Rillito Creek basin where artificial recharge of surface runoff is being considered. Concentrations of suspended sediment in streams generally increased with increases in streamflow and were higher during the summer. The surface water is a calcium and bicarbonate type, and the ground water is calcium sodium and bicarbonate type. Total trace ek=nents in surface water that exceeded the U.S. Environmental Protection Agency primary maximum contaminant levels for drinking-water standards were barium, beryllium, cadmium, chromium, lead, mercury and nickel. Most unfiltered samples for suspended gross alpha as uranium, and unadjusted gross alpha plus gross beta in surface water exceeded the U.S. Environmental Protection Agency and the State of Arizona drinking-water standards. Comparisons of trace- element concentrations in bottom sediment with those in soils of the western conterminous United States generally indicate similar concentrations for most of the trace elements, with the exceptions of scandium and tin. The maximum concentration of total nitrite plus nitrate as nitrogen in three ground- samples and total lead in one ground-water sample exceeded U.S. Environmental Protection Agency primary maximum contaminant levels for drinking- water standards, respectively. Seven organochlorine pesticides were detected in surface-water samples and nine in bottom-sediment samples. Three priority pollutants were detected in surface water, two were detected in ground water, and eleven were detected in bottom sediment. Low concentrations of oil and grease were detected in surface-water and bottom- sediment samples.

Silane Modification of Glass and Silica Surfaces to Obtain Equally Oil-Wet Surfaces in Glass-Covered Silicon Micromodel Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grate, Jay W.; Warner, Marvin G.; Pittman, Jonathan W.

2013-08-05

The wettability of silicon and glass surfaces can be modified by silanization. However, similar treatments of glass and silica surfaces using the same silane do not necessarily yield the same wettability as determined by the oil-water contact angle. In this technical note, surface cleaning pretreatments were investigated to determine conditions that would yield oil-wet surfaces on glass with similar wettability to silica surfaces treated with the same silane, and both air-water and oil-water contact angles were determined. Air-water contact angles were less sensitive to differences between silanized silica and glass surfaces, often yielding similar values while the oil-water contact anglesmore » were quite different. Borosilicate glass surfaces cleaned with standard cleaning solution 1 (SC1) yield intermediate-wet surfaces when silanized with hexamethyldisilazane, while the same cleaning and silanization yields oil-wet surfaces on silica. However, cleaning glass in boiling concentrated nitric acid creates a surface that can be silanized to obtain oil-wet surfaces using HDMS. Moreover, this method is effective on glass with prior thermal treatment at an elevated temperature of 400oC. In this way, silica and glass can be silanized to obtain equally oil-wet surfaces using HMDS. It is demonstrated that pretreatment and silanization is feasible in silicon-silica/glass micromodels previously assembled by anodic bonding, and that the change in wettability has a significant observable effect on immiscisble fluid displacements in the pore network.« less

Structure and Dynamics of Forsterite-scCO2/H2O Interfaces as a Function of Water Content

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kerisit, Sebastien N.; Weare, John H.; Felmy, Andrew R.

Molecular dynamics (MD) simulations of forsterite surfaces in contact with supercritical carbon dioxide (scCO2) fluids of varying water content were performed to determine the partition of water between the scCO2 fluid and the mineral surface, the nature of CO2 and H2O bonding at the interface, and the regions of the interface that may be conducive to HxCO3(2-x)- formation. Calculations of the free energy of the associative adsorption of water onto the (010) forsterite surface from the scCO2 phase indicated that the formation of a water film up to three-monolayer thick can be exothermic even for water contents below the watermore » saturation concentration of the scCO2 fluid. In MD simulations of scCO2/H2O mixtures in contact with the (010) forsterite surface, H2O was found to readily displace CO2 at the surface and, therefore, CO2 directly contacted the surface only for water coverages below two monolayers. For thicker water films, a two-monolayer hydration layer formed that CO2 could not penetrate. Simulations of the hydroxylated (010) surface and of the (011) surface suggested that this conclusion can be extended to forsterite surfaces with different surface structures and/or compositions. The density, diffusion, and degree of hydration of CO2 as well as the extent of CO2/H2O mixing at the interface were all predicted to depend strongly on the thickness of the water-rich film, i.e., on the water content of the scCO2 fluid.« less

Simulations of ecosystem hydrological processes using a unified multi-scale model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Xiaofan; Liu, Chongxuan; Fang, Yilin

2015-01-01

This paper presents a unified multi-scale model (UMSM) that we developed to simulate hydrological processes in an ecosystem containing both surface water and groundwater. The UMSM approach modifies the Navier–Stokes equation by adding a Darcy force term to formulate a single set of equations to describe fluid momentum and uses a generalized equation to describe fluid mass balance. The advantage of the approach is that the single set of the equations can describe hydrological processes in both surface water and groundwater where different models are traditionally required to simulate fluid flow. This feature of the UMSM significantly facilitates modelling ofmore » hydrological processes in ecosystems, especially at locations where soil/sediment may be frequently inundated and drained in response to precipitation, regional hydrological and climate changes. In this paper, the UMSM was benchmarked using WASH123D, a model commonly used for simulating coupled surface water and groundwater flow. Disney Wilderness Preserve (DWP) site at the Kissimmee, Florida, where active field monitoring and measurements are ongoing to understand hydrological and biogeochemical processes, was then used as an example to illustrate the UMSM modelling approach. The simulations results demonstrated that the DWP site is subject to the frequent changes in soil saturation, the geometry and volume of surface water bodies, and groundwater and surface water exchange. All the hydrological phenomena in surface water and groundwater components including inundation and draining, river bank flow, groundwater table change, soil saturation, hydrological interactions between groundwater and surface water, and the migration of surface water and groundwater interfaces can be simultaneously simulated using the UMSM. Overall, the UMSM offers a cross-scale approach that is particularly suitable to simulate coupled surface and ground water flow in ecosystems with strong surface water and groundwater interactions.« less

Effective use of surface-water management to control saltwater intrusion

NASA Astrophysics Data System (ADS)

Hughes, J. D.; White, J.

2012-12-01

The Biscayne aquifer in southeast Florida is susceptible to saltwater intrusion and inundation from rising sea-level as a result of high groundwater withdrawal rates and low topographic relief. Groundwater levels in the Biscayne aquifer are managed by an extensive canal system that is designed to control flooding, supply recharge to municipal well fields, and control saltwater intrusion. We present results from an integrated surface-water/groundwater model of a portion of the Biscayne aquifer to evaluate the ability of the existing managed surface-water control network to control saltwater intrusion. Surface-water stage and flow are simulated using a hydrodynamic model that solves the diffusive-wave approximation of the depth-integrated shallow surface-water equations. Variable-density groundwater flow and fluid density are solved using the Oberbeck--Boussinesq approximation of the three-dimensional variable-density groundwater flow equation and a sharp interface approximation, respectively. The surface-water and variable-density groundwater domains are implicitly coupled during each Picard iteration. The Biscayne aquifer is discretized into a multi-layer model having a 500-m square horizontal grid spacing. All primary and secondary surface-water features in the active model domain are discretized into segments using the 500-m square horizontal grid. A 15-year period of time is simulated and the model includes 66 operable surface-water control structures, 127 municipal production wells, and spatially-distributed daily internal and external hydrologic stresses. Numerical results indicate that the existing surface-water system can be effectively used in many locations to control saltwater intrusion in the Biscayne aquifer resulting from increases in groundwater withdrawals or sea-level rise expected to occur over the next 25 years. In other locations, numerical results indicate surface-water control structures and/or operations may need to be modified to control saltwater intrusion.

Molecular dynamics simulation of water at mineral surfaces: Structure, dynamics, energetics and hydrogen bonding

NASA Astrophysics Data System (ADS)

Kalinichev, A. G.; Wang, J.; Kirkpatrick, R.

2006-05-01

Fundamental molecular-level understanding of the properties of aqueous mineral interfaces is of great importance for many geochemical and environmental systems. Interaction between water and mineral surfaces substantially affects the properties of both phases, including the reactivity and functionality of the substrate surface, and the structure, dynamics, and energetics of the near surface aqueous phase. Experimental studies of interfacial water structure and dynamics using surface-sensitive techniques such as sum-frequency vibrational spectroscopy or X-ray and neutron reflectivity are not always possible for many practically important substrates, and their results often require interpretation concerning the atomistic mechanisms responsible for the observed behavior. Molecular computer simulations can provide new insight into the underlying molecular- level relationships between the inorganic substrate structure and composition and the structure, ordering, and dynamics of interfacial water. We have performed a series of molecular dynamics (MD) computer simulations of aqueous interfaces with several silicates (quartz, muscovite, and talc) and hydroxides (brucite, portlandite, gibbsite, Ca/Al and Mg/Al double hydroxides) to quantify the effects of the substrate mineral structure and composition on the structural, transport, and thermodynamic properties of water on these mineral surfaces. Due to the prevalent effects of the development of well-interconnected H-bonding networks across the mineral- water interfaces, all the hydroxide surfaces (including a fully hydroxylated quartz surface) show very similar H2O density profiles perpendicular to the interface. However, the predominant orientations of the interfacial H2O molecules and their detailed 2-dimensional near-surface structure and dynamics parallel to the interface are quite different reflecting the differences in the substrate structural charge distribution and the density and orientations of the surface OH groups. The H2O density profiles and other structural and dynamic characteristics of water at the two siloxane surfaces are very different from each other and from the hydroxide surfaces, since the muscovite surface is negatively charged and hydrophilic, while the talc surface is electrostatically neutral and hydrophobic. In general, at hydrophilic neutral surfaces both donating and accepting H-bonds from the H2O molecules are contributing to the development of the interfacial H-bond network, whereas at hydrophilic but charged surfaces only accepting or donating H-bonds with H2O molecules are possible. At the hydrophobic talc surface H-bonds among H2O molecules dominate the interfacial H-bond network and the water-surface interactions are very weak. The first water layer at all substrates is well ordered parallel to the surface, reflecting substrate crystal structures and indicating the reduced translational and orientational mobility of interfacial H2O molecules. At longer time scale (~100ps) their dynamics can be decomposed into a slow, virtually frozen, regime due to the substrate- bound H2O and a faster regime of almost free water reflecting the dynamics far from the surface. At shorter times (>10ps) the two dynamical regimes are superimposed. The much higher ordering of interfacial water (compared to bulk liquid) can not be adequately described as simply "ice-like". To some extent, it rather resembles the behavior of supercooled water.

Porous ceramic membrane with superhydrophobic and superoleophilic surface for reclaiming oil from oily water

NASA Astrophysics Data System (ADS)

Su, Changhong; Xu, Youqian; Zhang, Wei; Liu, Yang; Li, Jun

2012-01-01

A porous ceramic tube with superhydrophobic and superoleophilic surface was fabricated by sol-gel and then surface modification with polyurethane-polydimethysiloxane, and an oil-water separator based on the porous ceramic tube was erected to characterize superhydrophobic and superoleophilic surface's separation efficiency and velocity when being used to reclaim oil from oily water and complex oily water containing clay particle. The separator is fit for reclaiming oil from oily water.

Study of factors governing oil-water separation process using TiO₂ films prepared by spray deposition of nanoparticle dispersions.

PubMed

Gondal, Mohammed A; Sadullah, Muhammad S; Dastageer, Mohamed A; McKinley, Gareth H; Panchanathan, Divya; Varanasi, Kripa K

2014-08-27

Surfaces which possess extraordinary water attraction or repellency depend on surface energy, surface chemistry, and nano- and microscale surface roughness. Synergistic superhydrophilic-underwater superoleophobic surfaces were fabricated by spray deposition of nanostructured TiO2 on stainless steel mesh substrates. The coated meshes were then used to study gravity driven oil-water separation, where only the water from the oil-water mixture is allowed to permeate through the mesh. Oil-water separation efficiencies of up to 99% could be achieved through the coated mesh of pore sizes 50 and 100 μm, compared to no separation at all, that was observed in the case of uncoated meshes of the same material and pore sizes. An adsorbed water on the TiO2 coated surface, formation of a water-film between the wires that form the mesh and the underwater superoleophobicity of the structured surface are the key factors that contribute to the enhanced efficiency observed in oil-water separation. The nature of the oil-water separation process using this coated mesh (in which the mesh allows water to pass through the porous structure but resists wetting by the oil phase) minimizes the fouling of mesh so that the need for frequent replacement of the separating medium is reduced. The fabrication approach presented here can be applied for coating large surface areas and to develop a large-scale oil-water separation facility for oil-field applications and petroleum industries.

Moulding technique demonstrates the contribution of surface geometry to the super-hydrophobic properties of the surface of a water strider.

PubMed

Goodwyn, Pablo Perez; De Souza, Emerson; Fujisaki, Kenji; Gorb, Stanislav

2008-05-01

Water striders (Insecta, Heteroptera, Gerridae) have a complex three-dimensional waterproof hairy cover which renders them super-hydrophobic. This paper experimentally demonstrates for the first time the mechanism of the super-hydrophobicity of the cuticle of water striders. The complex two-level microstructure of the surface, including the smallest microtrichia (200-300 nm wide, 7-9 microm long), was successfully replicated using a two-step moulding technique. The mould surface exhibited super-hydrophobic properties similar to the original insect surface. The average water contact angle (CA) of the mould was 164.7 degrees , whereas the CA of the flat polymer was about 92 degrees . These results show that (i) in water striders, the topography of the surface plays a dominant role in super-hydrophobicity, (ii) very low surface energy bulk material (typically smaller than 0.020 N m(-1)) is not necessary to achieve super-hydrophobicity; and (3) the two-step moulding technique may be used to mimic quite complex biological functional surfaces.

Quantum Chemical Study of Water Adsorption on the Surfaces of SrTiO3 Nanotubes.

PubMed

Bandura, Andrei V; Kuruch, Dmitry D; Evarestov, Robert A

2015-07-20

We have studied the adsorption of water molecules on the inner and outer surfaces of nanotubes generated by rolling (001) layers of SrTiO3 cubic crystals. The stability and the atomic and electronic structures of the adsorbed layers are determined by using hybrid density functional theory. The absorption energy and the preferred adsorbate structure are essentially governed by the nature of the surface of the nanotube. Dissociative adsorption prevails on the outer nanotube surfaces. The stability of the adsorbed layers on the inner surfaces is related to the possibility of the formation of hydrogen bonds between water molecules and surface oxygen atoms, and depends on the surface curvature. The presence of water molecules on the inner surface of the nanotubes leads to an increase of the electronic band gap. Externally TiO2 -terminated nanotubes could be used for the photocatalytic decomposition of water by ultraviolet radiation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Efficacy of electrolysed oxidizing water in inactivating Vibrio parahaemolyticus on kitchen cutting boards and food contact surfaces.

PubMed

Chiu, T-H; Duan, J; Liu, C; Su, Y-C

2006-12-01

To determine the efficacy of electrolysed oxidizing (EO) water in inactivating Vibrio parahaemolyticus on kitchen cutting boards and food contact surfaces. Cutting boards (bamboo, wood and plastic) and food contact surfaces (stainless steel and glazed ceramic tile) were inoculated with V. parahaemolyticus. Viable cells of V. parahaemolyticus were detected on all cutting boards and food contact surfaces after 10 and 30 min, respectively, at room temperatures. Soaking inoculated food contact surfaces and cutting boards in distilled water for 1 and 3 min, respectively, resulted in various reductions of V. parahaemolyticus, but failed to remove the organism completely from surfaces. However, the treatment of EO water [pH 2.7, chlorine 40 ppm, oxidation-reduction potential 1151 mV] for 30, 45, and 60 s, completely inactivated V. parahaemolyticus on stainless steel, ceramic tile, and plastic cutting boards, respectively. EO water could be used as a disinfecting agent for inactivating V. parahaemolyticus on plastic and wood cutting boards and food contact surfaces. Rinsing the food contact surfaces with EO water or soaking cutting boards in EO water for up to 5 min could be a simple strategy to reduce cross-contamination of V. parahaemolyticus during food preparation.

Water organization between oppositely charged surfaces: Implications for protein sliding along DNA a)

NASA Astrophysics Data System (ADS)

Marcovitz, Amir; Naftaly, Aviv; Levy, Yaakov

2015-02-01

Water molecules are abundant in protein-DNA interfaces, especially in their nonspecific complexes. In this study, we investigated the organization and energetics of the interfacial water by simplifying the geometries of the proteins and the DNA to represent them as two equally and oppositely charged planar surfaces immersed in water. We found that the potential of mean force for bringing the two parallel surfaces into close proximity comprises energetic barriers whose properties strongly depend on the charge density of the surfaces. We demonstrated how the organization of the water molecules into discretized layers and the corresponding energetic barriers to dehydration can be modulated by the charge density on the surfaces, salt, and the structure of the surfaces. The 1-2 layers of ordered water are tightly bound to the charged surfaces representing the nonspecific protein-DNA complex. This suggests that water might mediate one-dimensional diffusion of proteins along DNA (sliding) by screening attractive electrostatic interactions between the positively charged molecular surface on the protein and the negatively charged DNA backbone and, in doing so, reduce intermolecular friction in a manner that smoothens the energetic landscape for sliding, and facilitates the 1D diffusion of the protein.

Surface-water quality-assurance plan for the U.S. Geological Survey Washington Water Science Center

USGS Publications Warehouse

Mastin, Mark C.

2016-02-19

This Surface-Water Quality-Assurance Plan documents the standards, policies, and procedures used by the U.S. Geological Survey Washington Water Science Center (WAWSC) for activities related to the collection, processing, storage, analysis, and publication of surface-water data. This plan serves as a guide to all WAWSC personnel involved in surface-water data activities, and changes as the needs and requirements of the WAWSC change. Regular updates to this plan represent an integral part of the quality-assurance process. In the WAWSC, direct oversight and responsibility by the hydrographer(s) assigned to a surface-water station, combined with team approaches in all work efforts, assure highquality data, analyses, reviews, and reports for cooperating agencies and the public.

Experimental demonstration of remote, passive acousto-optic sensing.

PubMed

Antonelli, Lynn; Blackmon, Fletcher

2004-12-01

Passively detecting underwater sound from the air can allow aircraft and surface vessels to monitor the underwater acoustic environment. Experimental research into an optical hydrophone is being conducted for remote, aerial detection of underwater sound. A laser beam is directed onto the water surface to measure the velocity of the vibrations occurring as the underwater acoustic signal reaches the water surface. The acoustically generated surface vibrations modulate the phase of the laser beam. Sound detection occurs when the laser is reflected back towards the sensor. Therefore, laser alignment on the specularly reflecting water surface is critical. As the water surface moves, the laser beam is reflected away from the photodetector and no signal is obtained. One option to mitigate this problem is to continually steer the laser onto a spot on the water surface that provides a direct back-reflection. Results are presented from a laboratory test that investigates the feasibility of the acousto-optic sensor detection on hydrostatic and hydrodynamic surfaces using a laser Doppler vibrometer in combination with a laser-based, surface normal glint tracker for remotely detecting underwater sound. This paper outlines the acousto-optic sensor and tracker concepts and presents experimental results comparing sensor operation under various sea surface conditions.

Bacterial community diversity and variation in spray water sources and the tomato fruit surface

PubMed Central

2011-01-01

Background Tomato (Solanum lycopersicum) consumption has been one of the most common causes of produce-associated salmonellosis in the United States. Contamination may originate from animal waste, insects, soil or water. Current guidelines for fresh tomato production recommend the use of potable water for applications coming in direct contact with the fruit, but due to high demand, water from other sources is frequently used. We sought to describe the overall bacterial diversity on the surface of tomato fruit and the effect of two different water sources (ground and surface water) when used for direct crop applications by generating a 454-pyrosequencing 16S rRNA dataset of these different environments. This study represents the first in depth characterization of bacterial communities in the tomato fruit surface and the water sources commonly used in commercial vegetable production. Results The two water sources tested had a significantly different bacterial composition. Proteobacteria was predominant in groundwater samples, whereas in the significantly more diverse surface water, abundant phyla also included Firmicutes, Actinobacteria and Verrucomicrobia. The fruit surface bacterial communities on tomatoes sprayed with both water sources could not be differentiated using various statistical methods. Both fruit surface environments had a high representation of Gammaproteobacteria, and within this class the genera Pantoea and Enterobacter were the most abundant. Conclusions Despite the major differences observed in the bacterial composition of ground and surface water, the season long use of these very different water sources did not have a significant impact on the bacterial composition of the tomato fruit surface. This study has provided the first next-generation sequencing database describing the bacterial communities living in the fruit surface of a tomato crop under two different spray water regimes, and therefore represents an important step forward towards the development of science-based metrics for Good Agricultural Practices. PMID:21510867

The Relationship Between Microscopic Grain Surface Structure and the Dynamic Capillary-Driven Advance of Water Films over Individual Dry Natural Sand Grains

NASA Astrophysics Data System (ADS)

Kibbey, T. C. G.; Adegbule, A.; Yan, S.

2017-12-01

The movement of nonvolatile solutes in unsaturated porous media at low water contents depends on transport in surface-associated water films. The focus of the work described here was on studying solute movement in water films advancing by capillary forces over initially-dry grain surfaces, to understand how microscopic surface roughness features influence the initial velocity of water film advance. For this work, water containing a non-adsorbing conservative tracer was used to track the movement of advancing water films. A stainless steel capillary tube connected to an external reservoir a fixed distance below the grain surface was used to transmit solution to the grain surface under negative pressure (positive capillary pressure), consistent with conditions that might be expected in the unsaturated zone. The small internal diameter of the capillary prevents solution from draining out of the capillary back into the reservoir. When the capillary is contacted with a grain surface, capillary forces that result from contact between the fluid and the rough grain surface cause water films to wick across the grain surface. Multiple experiments were conducted on the same grain, rotating the grain and varying the capillary contact point around the circumference of the grain. Imaging was conducted at fixed intervals using an automated Extended Depth of Field (EDF) imaging system, and images were analyzed to determine initial velocity. Grain surfaces were then characterized through scanning electron microscope (SEM) imaging, using a hybrid stereoscopic reconstruction method designed to extract maximum detail in creating elevation maps of geologic surfaces from tilted pairs of SEM images. The resulting elevation maps were used to relate surface roughness profiles around the grain with initial velocities. Results suggest that velocity varies significant with contact point around an individual grain, and correlates quantitatively with the local grain surface structure. Preliminary simulation results will also be discussed.

Water surface capturing by image processing

USDA-ARS?s Scientific Manuscript database

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...

Developing the greatest Blue Economy: Water productivity, fresh water depletion, and virtual water trade in the Great Lakes basin

NASA Astrophysics Data System (ADS)

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

2016-12-01

The Great Lakes basin hosts the world's most abundant surface fresh water reserve. Historically an industrial and natural resource powerhouse, the region has suffered economic stagnation in recent decades. Meanwhile, growing water resource scarcity around the world is creating pressure on water-intensive human activities. This situation creates the potential for the Great Lakes region to sustainably utilize its relative water wealth for economic benefit. We combine economic production and trade datasets with water consumption data and models of surface water depletion in the region. We find that, on average, the current economy does not create significant impacts on surface waters, but there is some risk that unregulated large water uses can create environmental flow impacts if they are developed in the wrong locations. Water uses drawing on deep groundwater or the Great Lakes themselves are unlikely to create a significant depletion, and discharge of groundwater withdrawals to surface waters offsets most surface water depletion. This relative abundance of surface water means that science-based management of large water uses to avoid accidentally creating "hotspots" is likely to be successful in avoiding future impacts, even if water use is significantly increased. Commercial water uses are the most productive, with thermoelectric, mining, and agricultural water uses in the lowest tier of water productivity. Surprisingly for such a water-abundant economy, the region is a net importer of water-derived goods and services. This, combined with the abundance of surface water, suggests that the region's water-based economy has room to grow in the 21st century.

First principles study of the atomic layer deposition of alumina by TMA-H2O-process.

PubMed

Weckman, Timo; Laasonen, Kari

2015-07-14

Atomic layer deposition (ALD) is a coating technology used to produce highly uniform thin films. Aluminiumoxide, Al2O3, is mainly deposited using trimethylaluminium (TMA) and water as precursors and is the most studied ALD-process to date. However, only few theoretical studies have been reported in the literature. The surface reaction mechanisms and energetics previously reported focus on a gibbsite-like surface model but a more realistic description of the surface can be achieved when the hydroxylation of the surface is taken into account using dissociatively adsorbed water molecules. The adsorbed water changes the structure of the surface and reaction energetics change considerably when compared to previously studied surface model. Here we have studied the TMA-H2O process using density functional theory on a hydroxylated alumina surface and reproduced the previous results for comparison. Mechanisms and energetics during both the TMA and the subsequent water pulse are presented. TMA is found to adsorb exothermically onto the surface. The reaction barriers for the ligand-exchange reactions between the TMA and the surface hydroxyl groups were found to be much lower compared to previously presented results. TMA dissociation on the surface is predicted to saturate at monomethylaluminium. Barriers for proton diffusion between surface sites are observed to be low. TMA adsorption was also found to be cooperative with the formation of methyl bridges between the adsorbants. The water pulse was studied using single water molecules reacting with the DMA and MMA surface species. Barriers for these reactions were found to reasonable in the process conditions. However, stabilizing interactions amongst water molecules were found to lower the reaction barriers and the dynamical nature of water is predicted to be of importance. It is expected that these calculations can only set an upper limit for the barriers during the water pulse.

Groundwater impacts on surface water quality and nutrient loads in lowland polder catchments: monitoring the greater Amsterdam area

NASA Astrophysics Data System (ADS)

Yu, Liang; Rozemeijer, Joachim; van Breukelen, Boris M.; Ouboter, Maarten; van der Vlugt, Corné; Broers, Hans Peter

2018-01-01

The Amsterdam area, a highly manipulated delta area formed by polders and reclaimed lakes, struggles with high nutrient levels in its surface water system. The polders receive spatially and temporally variable amounts of water and nutrients via surface runoff, groundwater seepage, sewer leakage, and via water inlets from upstream polders. Diffuse anthropogenic sources, such as manure and fertiliser use and atmospheric deposition, add to the water quality problems in the polders. The major nutrient sources and pathways have not yet been clarified due to the complex hydrological system in lowland catchments with both urban and agricultural areas. In this study, the spatial variability of the groundwater seepage impact was identified by exploiting the dense groundwater and surface water monitoring networks in Amsterdam and its surrounding polders. A total of 25 variables (concentrations of total nitrogen (TN), total phosphorus (TP), NH4, NO3, HCO3, SO4, Ca, and Cl in surface water and groundwater, N and P agricultural inputs, seepage rate, elevation, land-use, and soil type) for 144 polders were analysed statistically and interpreted in relation to sources, transport mechanisms, and pathways. The results imply that groundwater is a large source of nutrients in the greater Amsterdam mixed urban-agricultural catchments. The groundwater nutrient concentrations exceeded the surface water environmental quality standards (EQSs) in 93 % of the polders for TP and in 91 % for TN. Groundwater outflow into the polders thus adds to nutrient levels in the surface water. High correlations (R2 up to 0.88) between solutes in groundwater and surface water, together with the close similarities in their spatial patterns, confirmed the large impact of groundwater on surface water chemistry, especially in the polders that have high seepage rates. Our analysis indicates that the elevated nutrient and bicarbonate concentrations in the groundwater seepage originate from the decomposition of organic matter in subsurface sediments coupled to sulfate reduction and possibly methanogenesis. The large loads of nutrient-rich groundwater seepage into the deepest polders indirectly affect surface water quality in the surrounding area, because excess water from the deep polders is pumped out and used to supply water to the surrounding infiltrating polders in dry periods. The study shows the importance of the connection between groundwater and surface water nutrient chemistry in the greater Amsterdam area. We expect that taking account of groundwater-surface water interaction is also important in other subsiding and urbanising deltas around the world, where water is managed intensively in order to enable agricultural productivity and achieve water-sustainable cities.

Surface-Enhanced Separation of Water from Hydrocarbons: Potential Dewatering Membranes for the Catalytic Fast Pyrolysis of Pine Biomass

DOE PAGES

Engtrakul, Dr. Chaiwat; Hu, Michael Z.; Bischoff, Brian L; ...

2016-01-01

The impact of surface-selective coatings on water permeation through a membrane when exposed to catalytic fast pyrolysis (CFP) vapor products was studied by tailoring the surface properties of the membrane coating from superhydrophilic to superhydrophobic. Our approach utilized high-performance architectured surface-selective (HiPAS) membranes that were inserted after a CFP reactor. At this insertion point, the inner wall surface of a tubular membrane was exposed to a mixture of water and upgraded product vapors, including light gases and deoxygenated hydrocarbons. Under proper membrane operating conditions, a high selectivity for water over 1-ring upgraded biomass pyrolysis hydrocarbons was observed due to amore » surface-enhanced capillary condensation process. Owing to this surface-enhanced effect, HiPAS membranes have the potential to enable high flux separations suggesting that water can be selectively removed from the CFP product vapors.« less

Surface-Enhanced Separation of Water from Hydrocarbons: Potential Dewatering Membranes for the Catalytic Fast Pyrolysis of Pine Biomass

DOE Office of Scientific and Technical Information (OSTI.GOV)

Engtrakul, Chaiwat; Hu, Michael Z.; Bischoff, Brian L.

2016-10-20

The impact of surface-selective coatings on water permeation through a membrane when exposed to catalytic fast pyrolysis (CFP) vapor products was studied by tailoring the surface properties of the membrane coating from superhydrophilic to superhydrophobic. Our approach used high-performance architectured surface-selective (HiPAS) membranes that were inserted after a CFP reactor. At this insertion point, the inner wall surface of a tubular membrane was exposed to a mixture of water and upgraded product vapors, including light gases and deoxygenated hydrocarbons. Under proper membrane operating conditions, a high selectivity for water over one-ring upgraded biomass pyrolysis hydrocarbons was observed as a resultmore » of a surface-enhanced capillary condensation process. Owing to this surface-enhanced effect, HiPAS membranes have the potential to enable high flux separations, suggesting that water can be selectively removed from the CFP product vapors.« less

Investigating How Contact Angle Effects the Interaction between Water and a Hydrophobic Surface

NASA Astrophysics Data System (ADS)

Poynor, Adele; Neidig, Caitlyn

2012-02-01

By definition hydrophobic substances hate water. 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. Contact angle is a measure of how hydrophobic a surface is. We have employed an automated home-built Surface Plasmon Resonance (SPR) apparatus to investigate the effect of varying the contact angle on the depletion layer

Using a hybrid model to predict solute transfer from initially saturated soil into surface runoff with controlled drainage water.

PubMed

Tong, Juxiu; Hu, Bill X; Yang, Jinzhong; Zhu, Yan

2016-06-01

The mixing layer theory is not suitable for predicting solute transfer from initially saturated soil to surface runoff water under controlled drainage conditions. By coupling the mixing layer theory model with the numerical model Hydrus-1D, a hybrid solute transfer model has been proposed to predict soil solute transfer from an initially saturated soil into surface water, under controlled drainage water conditions. The model can also consider the increasing ponding water conditions on soil surface before surface runoff. The data of solute concentration in surface runoff and drainage water from a sand experiment is used as the reference experiment. The parameters for the water flow and solute transfer model and mixing layer depth under controlled drainage water condition are identified. Based on these identified parameters, the model is applied to another initially saturated sand experiment with constant and time-increasing mixing layer depth after surface runoff, under the controlled drainage water condition with lower drainage height at the bottom. The simulation results agree well with the observed data. Study results suggest that the hybrid model can accurately simulate the solute transfer from initially saturated soil into surface runoff under controlled drainage water condition. And it has been found that the prediction with increasing mixing layer depth is better than that with the constant one in the experiment with lower drainage condition. Since lower drainage condition and deeper ponded water depth result in later runoff start time, more solute sources in the mixing layer are needed for the surface water, and larger change rate results in the increasing mixing layer depth.

Terminal velocity and drag reduction measurements on superhydrophobic spheres

NASA Astrophysics Data System (ADS)

McHale, G.; Shirtcliffe, N. J.; Evans, C. R.; Newton, M. I.

2009-02-01

Super water-repellent surfaces occur naturally on plants and aquatic insects and are created in the laboratory by combining micro- or nanoscale surface topographic features with hydrophobic surface chemistry. When such types of water-repellent surfaces are submerged they can retain a film of air (a plastron). In this work, we report measurements of the terminal velocity of solid acrylic spheres with various surface treatments settling under the action of gravity in water. We observed increases in terminal velocity corresponding to drag reduction of between 5% and 15% for superhydrophobic surfaces that carry plastrons.

Detecting surface runoff location in a small catchment using distributed and simple observation method

NASA Astrophysics Data System (ADS)

Dehotin, Judicaël; Breil, Pascal; Braud, Isabelle; de Lavenne, Alban; Lagouy, Mickaël; Sarrazin, Benoît

2015-06-01

Surface runoff is one of the hydrological processes involved in floods, pollution transfer, soil erosion and mudslide. Many models allow the simulation and the mapping of surface runoff and erosion hazards. Field observations of this hydrological process are not common although they are crucial to evaluate surface runoff models and to investigate or assess different kinds of hazards linked to this process. In this study, a simple field monitoring network is implemented to assess the relevance of a surface runoff susceptibility mapping method. The network is based on spatially distributed observations (nine different locations in the catchment) of soil water content and rainfall events. These data are analyzed to determine if surface runoff occurs. Two surface runoff mechanisms are considered: surface runoff by saturation of the soil surface horizon and surface runoff by infiltration excess (also called hortonian runoff). The monitoring strategy includes continuous records of soil surface water content and rainfall with a 5 min time step. Soil infiltration capacity time series are calculated using field soil water content and in situ measurements of soil hydraulic conductivity. Comparison of soil infiltration capacity and rainfall intensity time series allows detecting the occurrence of surface runoff by infiltration-excess. Comparison of surface soil water content with saturated water content values allows detecting the occurrence of surface runoff by saturation of the soil surface horizon. Automatic records were complemented with direct field observations of surface runoff in the experimental catchment after each significant rainfall event. The presented observation method allows the identification of fast and short-lived surface runoff processes at a small spatial and temporal resolution in natural conditions. The results also highlight the relationship between surface runoff and factors usually integrated in surface runoff mapping such as topography, rainfall parameters, soil or land cover. This study opens interesting prospects for the use of spatially distributed measurement for surface runoff detection, spatially distributed hydrological models implementation and validation at a reasonable cost.

Dual-Functional Superhydrophobic Textiles with Asymmetric Roll-Down/Pinned States for Water Droplet Transportation and Oil-Water Separation.

PubMed

Su, Xiaojing; Li, Hongqiang; Lai, Xuejun; Zhang, Lin; Liao, Xiaofeng; Wang, Jing; Chen, Zhonghua; He, Jie; Zeng, Xingrong

2018-01-31

Superhydrophobic surfaces with tunable adhesion from lotus-leaf to rose-petal states have generated much attention for their potential applications in self-cleaning, anti-icing, oil-water separation, microdroplet transportation, and microfluidic devices. Herein we report a facile magnetic-field-manipulation strategy to fabricate dual-functional superhydrophobic textiles with asymmetric roll-down/pinned states on the two surfaces of the textile simultaneously. Upon exposure to a static magnetic field, fluoroalkylsilane-modified iron oxide (F-Fe 3 O 4 ) nanoparticles in polydimethylsiloxane (PDMS) moved along the magnetic field to construct discrepant hierarchical structures and roughnesses on the two sides of the textile. The positive surface (closer to the magnet, or P-surface) showed a water contact angle up to 165°, and the opposite surface (or O-surface) had a water contact angle of 152.5°. The P-surface where water droplets easily slid off with a sliding angle of 7.5° appeared in the "roll-down" state as Cassie mode, while the O-surface was in the "pinned" state as Wenzel mode, where water droplets firmly adhered even at vertical (90°) and inverted (180°) angles. The surface morphology and wetting mode were adjustable by varying the ratios of F-Fe 3 O 4 nanoparticles and PDMS. By taking advantage of the asymmetric adhesion behaviors, the as-fabricated superhydrophobic textile was successfully applied in no-loss microdroplet transportation and oil-water separation. Our method is simple and cost-effective. The fabricated textile has the characteristics of superhydrophobicity, magnetic responsiveness, excellent chemical stability, adjustable surface morphology, and controllable adhesion. Our findings conceivably stand out as a new tool to fabricate functional superhydrophobic materials with asymmetric surface properties for various potential applications.

[Spatial distribution and pollution assessment of heavy metals in the tidal reach and its adjacent sea estuary of Daliaohe area, China ].

PubMed

Zhang, Lei; Qin, Yan-wen; Ma, Ying-qun; Zhao, Yan-min; Shi, Yao

2014-09-01

The aim of this article was to explore the pollution level of heavy metals in the tidal reach and its adjacent sea estuary of Daliaohe area. The contents and spatial distribution of As, Cd, Cr, Cu, Ph and Zn in surface water, suspended solids and surface sediments were analyzed respectively. The integrated pollution index and geoaccumulation index were used to evaluate the contamination degree of heavy metals in surface water and surface sediments respectively. The results indicated that the contents of heavy metals in surface water was in the order of Pb < Cu < Cd < Cr < As < Zn. The heavy metal contents in surface water increased from river to sea. Compared with the contents of heavy metals in surface water of the typical domestic estuary in China, the overall contents of heavy metals in surface water were at a higher level. The contents of heavy metals in suspended solids was in the order of Cd < Cu < As < Cr

Testing the performance of superhydrophobic aluminum surfaces.

PubMed

Ruiz-Cabello, F Javier Montes; Ibáñez-Ibáñez, Pablo F; Gómez-Lopera, J Francisco; Martínez-Aroza, José; Cabrerizo-Vílchez, Miguel; Rodríguez-Valverde, Miguel A

2017-12-15

The analysis of wetting properties of superhydrophobic surfaces may be a difficult task due to the restless behavior of drops on this type of surfaces and the limitations of goniometry for high contact angles. A method to validate the performance of superhydrophobic surfaces, rather than standard goniometry, is required. In this work, we used bouncing drop dynamics as a useful tool to predict the water repellency of different superhydrophobic surfaces. From bouncing drop experiments conducted over a wide range of superhydrophobic surfaces, we found that those surfaces with a proper roughness degree and homogeneous chemical composition showed higher water-repellency. We also conducted a drop condensation study at saturating conditions aimed to determine whether there is direct correlation between water repellency and condensation delay. We found that the drop condensation process is strongly related to the surface topography, as well as the intrinsic wettability. The condensation is promoted on rough surfaces but it is delayed on intrinsically hydrophobic surfaces. However, the differences found in condensation delay between the superhydrophobic surfaces explored in this study cannot be justified by their chemical homogeneity nor their efficiency as water repellent surfaces, separately. Copyright © 2017 Elsevier Inc. All rights reserved.

Quantification of surface water volume changes in the Mackenzie Delta using satellite multi-mission data

NASA Astrophysics Data System (ADS)

Normandin, Cassandra; Frappart, Frédéric; Lubac, Bertrand; Bélanger, Simon; Marieu, Vincent; Blarel, Fabien; Robinet, Arthur; Guiastrennec-Faugas, Léa

2018-02-01

Quantification of surface water storage in extensive floodplains and their dynamics are crucial for a better understanding of global hydrological and biogeochemical cycles. In this study, we present estimates of both surface water extent and storage combining multi-mission remotely sensed observations and their temporal evolution over more than 15 years in the Mackenzie Delta. The Mackenzie Delta is located in the northwest of Canada and is the second largest delta in the Arctic Ocean. The delta is frozen from October to May and the recurrent ice break-up provokes an increase in the river's flows. Thus, this phenomenon causes intensive floods along the delta every year, with dramatic environmental impacts. In this study, the dynamics of surface water extent and volume are analysed from 2000 to 2015 by combining multi-satellite information from MODIS multispectral images at 500 m spatial resolution and river stages derived from ERS-2 (1995-2003), ENVISAT (2002-2010) and SARAL (since 2013) altimetry data. The surface water extent (permanent water and flooded area) peaked in June with an area of 9600 km2 (±200 km2) on average, representing approximately 70 % of the delta's total surface. Altimetry-based water levels exhibit annual amplitudes ranging from 4 m in the downstream part to more than 10 m in the upstream part of the Mackenzie Delta. A high overall correlation between the satellite-derived and in situ water heights (R > 0.84) is found for the three altimetry missions. Finally, using altimetry-based water levels and MODIS-derived surface water extents, maps of interpolated water heights over the surface water extents are produced. Results indicate a high variability of the water height magnitude that can reach 10 m compared to the lowest water height in the upstream part of the delta during the flood peak in June. Furthermore, the total surface water volume is estimated and shows an annual variation of approximately 8.5 km3 during the whole study period, with a maximum of 14.4 km3 observed in 2006. The good agreement between the total surface water volume retrievals and in situ river discharges (R = 0.66) allows for validation of this innovative multi-mission approach and highlights the high potential to study the surface water extent dynamics.

Modelling surface-water depression storage in a Prairie Pothole Region

USGS Publications Warehouse

Hay, Lauren E.; Norton, Parker A.; Viger, Roland; Markstrom, Steven; Regan, R. Steven; Vanderhoof, Melanie

2018-01-01

In this study, the Precipitation-Runoff Modelling System (PRMS) was used to simulate changes in surface-water depression storage in the 1,126-km2 Upper Pipestem Creek basin located within the Prairie Pothole Region of North Dakota, USA. The Prairie Pothole Region is characterized by millions of small water bodies (or surface-water depressions) that provide numerous ecosystem services and are considered an important contribution to the hydrologic cycle. The Upper Pipestem PRMS model was extracted from the U.S. Geological Survey's (USGS) National Hydrologic Model (NHM), developed to support consistent hydrologic modelling across the conterminous United States. The Geospatial Fabric database, created for the USGS NHM, contains hydrologic model parameter values derived from datasets that characterize the physical features of the entire conterminous United States for 109,951 hydrologic response units. Each hydrologic response unit in the Geospatial Fabric was parameterized using aggregated surface-water depression area derived from the National Hydrography Dataset Plus, an integrated suite of application-ready geospatial datasets. This paper presents a calibration strategy for the Upper Pipestem PRMS model that uses normalized lake elevation measurements to calibrate the parameters influencing simulated fractional surface-water depression storage. Results indicate that inclusion of measurements that give an indication of the change in surface-water depression storage in the calibration procedure resulted in accurate changes in surface-water depression storage in the water balance. Regionalized parameterization of the USGS NHM will require a proxy for change in surface-storage to accurately parameterize surface-water depression storage within the USGS NHM.

Understanding heterogeneity and data assimilation in karst groundwater surface water interactions: The role of geophysics and hydrologic models in a semi-confined aquifer

NASA Astrophysics Data System (ADS)

Meyerhoff, Steven B.

Groundwater and surface water historically have been treated as different entities. Due to this, planning and development of groundwater and surface water resources, both quantity and quality are often also treated separately. Recently, there has been work to characterize groundwater and surface water as a single system. Karstic systems are widely influenced by these interactions due to varying permeability, fracture geometry and porosity. Here, three different approaches are used to characterize groundwater surface water interactions in karstic environments. 1) A hydrologic model, ParFlow, is conditioned with known subsurface data to determine whether a reduction in subsurface uncertainty will enhance the prediction of surface water variables. A reduction in subsurface uncertainty resulted in substantial reductions in uncertainty in Hortonian runoff and less reductions in Dunne runoff. 2) Geophysical data is collected at a field site in O'leno State Park, Florida to visualize groundwater and surface water interactions in karstic environments. Significant changes in resistivity are seen through time at two locations. It is hypothesized that these changes are related to changing fluid source waters (e.g groundwater or surface water). 3). To confirm these observations an ensemble of synthetic forward models are simulated, inverted and compared directly with field observations and End-Member-Mixing-Analysis (EMMA). Field observations and synthetic models have comparable resistivity anomalies patterns and mixing fractions. This allows us to characterize and quantify subsurface mixing of groundwater and surface in karst environments. These three approaches (hydrologic models, field data and forward model experiments), (1) show the complexity and dynamics of groundwater and surface mixing in karstic environments in varying flow conditions, (2) showcase a novel geophysical technique to visualize groundwater and surface water interactions and (3) confirm hypothesis of flow and mixing in subsurface karst environments.

The Research of Correlation of Water Surface Spectral and Sediment Parameters

NASA Astrophysics Data System (ADS)

Li, J.; Gong, G.; Fang, W.; Sun, W.

2018-04-01

In the method of survey underwater topography using remote sensing, and the water surface spectral reflectance R, which remote sensing inversion results were closely related to affects by the water and underwater sediment and other aspects, especially in shallow nearshore coastal waters, different sediment types significantly affected the reflectance changes. Therefore, it was of great significance of improving retrieval accuracy to explore the relation of sediment and water surface spectral reflectance. In this study, in order to explore relationship, we used intertidal sediment sand samples in Sheyang estuary, and in the laboratory measured and calculated the chroma indicators, and the water surface spectral reflectance. We found that water surface spectral reflectance had a high correlation with the chroma indicators; research result stated that the color of the sediment had an very important impact on the water surface spectral, especially in Red-Green chroma a*. Also, the research determined the sensitive spectrum bands of the Red-Green chroma a*, which were 636-617 nm, 716-747 nm and 770-792 nm.

Durable, Low-Surface-Energy Treatments

NASA Technical Reports Server (NTRS)

Willis, Paul B.; Mcelroy, Paul M.; Hickey, Gregory S.

1992-01-01

Chemical treatment for creation of durable, low-surface-energy coatings for glass, ceramics and other protonated surfaces easily applied, and creates very thin semipermanent film with extremely low surface tension. Exhibits excellent stability; surfaces retreated if coating becomes damaged or eroded. Uses include water-repellent surfaces, oil-repellent surfaces, antimigration barriers, corrosion barriers, mold-release agents, and self-cleaning surfaces. Film resists wetting by water, alcohols, hydrocarbon solvents, and silicone oil. Has moderate resistance to abrasion, such as rubbing with cloths, and compression molding to polymers and composite materials.

Method and apparatus for production of subsea hydrocarbon formations

DOEpatents

Blandford, Joseph W.

1995-01-01

A system for controlling, separating, processing and exporting well fluids produced from subsea hydrocarbon formations is disclosed. The subsea well tender system includes a surface buoy supporting one or more decks above the water surface for accommodating equipment to process oil, gas and water recovered from the subsea hydrocarbon formation. The surface buoy includes a surface-piercing central flotation column connected to one or more external floatation tanks located below the water surface. The surface buoy is secured to the seabed by one or more tendons which are anchored to a foundation with piles imbedded in the seabed. The system accommodates multiple versions on the surface buoy configuration.

Hydrophilic directional slippery rough surfaces for water harvesting

PubMed Central

Sun, Nan; Nielsen, Steven O.; Wang, Jing

2018-01-01

Multifunctional surfaces that are favorable for both droplet nucleation and removal are highly desirable for water harvesting applications but are rare. Inspired by the unique functions of pitcher plants and rice leaves, we present a hydrophilic directional slippery rough surface (SRS) that is capable of rapidly nucleating and removing water droplets. Our surfaces consist of nanotextured directional microgrooves in which the nanotextures alone are infused with hydrophilic liquid lubricant. We have shown through molecular dynamics simulations that the physical origin of the efficient droplet nucleation is attributed to the hydrophilic surface functional groups, whereas the rapid droplet removal is due to the significantly reduced droplet pinning of the directional surface structures and slippery interface. We have further demonstrated that the SRS, owing to its large surface area, hydrophilic slippery interface, and directional liquid repellency, outperforms conventional liquid-repellent surfaces in water harvesting applications. PMID:29670942

Potentiometric surface of the upper Floridan Aquifer in the St. Johns River Water Management District and vicinity, Florida, September, 2004

USGS Publications Warehouse

Kinnaman, Sandra L.

2005-01-01

Introduction: This map depicts the potentiometric surface of the Upper Floridan aquifer in the St. Johns River Water Management District and vicinity in September 2004. Potentiometric contours are based on water-level measurements collected at 608 wells during the period September 14-October 1, near the end of the wet season. The shapes of some contours have been inferred from previous potentiometric-surface maps with larger well networks. The potentiometric surface of the carbonate Upper Floridan aquifer responds mainly to rainfall, and more locally, to ground-water withdrawals. Potentiometric-surface highs generally correspond to topographic highs where the aquifer is recharged. Springs and areas of diffuse upward leakage naturally discharge water from the aquifer and are most prevalent along the St. Johns River. Areas of discharge are reflected by depressions in the potentiometric surface. Ground-water withdrawals locally have lowered the potentiometric surface. Ground water in the Upper Floridan aquifer generally flows from potentiometric highs to potentiometric lows in a direction perpendicular to the contours.

Potentiometric Surface of the Upper Floridan Aquifer in the St. Johns River Water Management District and Vicinity, Florida, May, 2004

USGS Publications Warehouse

Kinnaman, Sandra L.; Knowles, Leel

2004-01-01

INTRODUCTION This map depicts the potentiometric surface of the Upper Floridan aquifer in the St. Johns River Water Management District and vicinity in May 2001. Potentiometric contours are based on water-level measurements collected at 684 wells during the period May 2 - 30, near the end of the dry season. The shapes of some contours have been inferred from previous potentiometric-surface maps with larger well networks. The potentiometric surface of the carbonate Upper Floridan aquifer responds mainly to rainfall, and more locally, to ground-water withdrawals. Potentiometric-surface highs generally correspond to topographic highs where the aquifer is recharged. Springs and areas of diffuse upward leakage naturally discharge water from the aquifer and are most prevalent along the St. Johns River. Areas of discharge are reflected by depressions in the potentiometric surface. Ground-water withdrawals locally have lowered the potentiometric surface. Ground water in the Upper Floridan aquifer generally flows from potentiometric highs to potentiometric lows in a direction perpendicular to the contours.

How well Can We Classify SWOT-derived Water Surface Profiles?

NASA Astrophysics Data System (ADS)

Frasson, R. P. M.; Wei, R.; Picamilh, C.; Durand, M. T.

2015-12-01

The upcoming Surface Water Ocean Topography (SWOT) mission will detect water bodies and measure water surface elevation throughout the globe. Within its continental high resolution mask, SWOT is expected to deliver measurements of river width, water elevation and slope of rivers wider than ~50 m. The definition of river reaches is an integral step of the computation of discharge based on SWOT's observables. As poorly defined reaches can negatively affect the accuracy of discharge estimations, we seek strategies to break up rivers into physically meaningful sections. In the present work, we investigate how accurately we can classify water surface profiles based on simulated SWOT observations. We assume that most river sections can be classified as either M1 (mild slope, with depth larger than the normal depth), or A1 (adverse slope with depth larger than the critical depth). This assumption allows the classification to be based solely on the second derivative of water surface profiles, with convex profiles being classified as A1 and concave profiles as M1. We consider a HEC-RAS model of the Sacramento River as a representation of the true state of the river. We employ the SWOT instrument simulator to generate a synthetic pass of the river, which includes our best estimates of height measurement noise and geolocation errors. We process the resulting point cloud of water surface heights with the RiverObs package, which delineates the river center line and draws the water surface profile. Next, we identify inflection points in the water surface profile and classify the sections between the inflection points. Finally, we compare our limited classification of simulated SWOT-derived water surface profile to the "exact" classification of the modeled Sacramento River. With this exercise, we expect to determine if SWOT observations can be used to find inflection points in water surface profiles, which would bring knowledge of flow regimes into the definition of river reaches.

Occurrence of seven artificial sweeteners in the aquatic environment and precipitation of Tianjin, China.

PubMed

Gan, Zhiwei; Sun, Hongwen; Feng, Biting; Wang, Ruonan; Zhang, Yanwei

2013-09-15

Seventy water samples, including wastewaters, tap waters, fresh surface waters, coastal waters, groundwaters, and precipitation samples, from Tianjin, China, were analyzed for seven commonly used artificial sweeteners (ASs). The concentrations of the investigated ASs were generally in the order of wastewater treatment plant (WWTP) influent > WWTP effluent > surface water > tap water > groundwater ≈ precipitation, while the composition profiles of ASs varied in different waters. Acesulfame, sucralose, cyclamate, and saccharin were consistently detected in surface waters and ranged from 50 ng/L to 0.12 mg/L, while acesulfame was the dominant AS in surface and tap waters. Aspartame was found in all of the surface waters at a concentration up to 0.21 μg/L, but was not found in groundwaters and tap waters. Neotame and neohesperidin dihydrochalcone were less frequently detected and the concentrations were low. The concentrations of the ASs in some of the surface waters were of the same order with those in the WWTP influents, but not with the effluents, indicating there are probably untreated discharges into the surface waters. The ASs were detected in precipitation samples with high frequency, and acesulfame, saccharin, and cyclamate were the predominant ASs, with concentrations ranging from 3.5 ng/L to 1.3 μg/L. A gross estimation revealed that precipitation may act as a source for saccharin and cyclamate in the surface environment of Tianjin city. Moreover, the presence of ASs in the atmosphere was primarily assessed by taking 4 air samples to evaluate their potential source in precipitation. Copyright © 2013 Elsevier Ltd. All rights reserved.

Water Cycling in the North Polar Region of Mars

NASA Technical Reports Server (NTRS)

Tamppari, L. K.; Smith, M. D.; Bass, D. S.

2003-01-01

To date, there has been no comprehensive study to understand the partitioning of water into vapor and ice clouds, and the associated effects of dust and surface temperature in the north polar region. Ascertaining the degree to which water is transported out of the cap region versus within the cap region will give much needed insight into the overall story of water cycling on a seasonal basis. In particular, understanding the mechanism for the polar cap surface albedo changes would go along way in comprehending the sources and sinks of water in the northern polar region. We approach this problem by examining Thermal Emission Spectrometer (TES) atmospheric and surface data acquired in the northern summer season and comparing it to Viking data when possible. Because the TES instrument spans the absorption bands of water vapor, water ice, dust, and measures surface temperature, all three aerosols and surface temperature can be retrieved simultaneously. This presentation will show our latest results on the water vapor, water-ice clouds seasonal and spatial distributions, as well as surface temperatures and dust distribution which may lend insight into where the water is going.

Summary of pesticide data from streams and wells in the Potomac River Basin, 1993-96

USGS Publications Warehouse

Donnelly, Colleen A.; Ferrari, Matthew J.

1998-01-01

Eighty-five water-soluble pesticides and pesticide degradation products were analyzed in 384 surface-water and ground-water samples collected from the Potomac River Basin during March 1993 through September 1996. Thirty-nine of these compounds were detected in surface-water samples and 16 were detected in ground-water samples. At least one pesticide was detected in 86 percent of the streams sampled and 45 percent of the wells sampled. Pesticides were detected more frequently and at higher concentrations in surface water than in ground water. The following four herbicides and one degradation product were the most frequently detected pesticides in both surface water and ground water: atrazine and metolachlor, which are used primarily on corn and soybean crops; prometon, which is used primarily in nonagricultural (urban and suburban) areas; simazine, which is used in both agricultural and nonagricultural areas, and desethylatrazine, which is one of the degradation products of atrazine. Insecticides were detected more frequently in surface water than in ground water. Diazinon, chlorpyrifos, and gamma-HCH (Undone) were found in more than 10 percent of surface-water samples, but in none of the ground-water samples.

Evidence for phase separation of ethanol-water mixtures at the hydrogen terminated nanocrystalline diamond surface.

PubMed

Janssens, Stoffel D; Drijkoningen, Sien; Saitner, Marc; Boyen, Hans-Gerd; Wagner, Patrick; Larsson, Karin; Haenen, Ken

2012-07-28

Interactions between ethanol-water mixtures and a hydrophobic hydrogen terminated nanocrystalline diamond surface, are investigated by sessile drop contact angle measurements. The surface free energy of the hydrophobic surface, obtained with pure liquids, differs strongly from values obtained by ethanol-water mixtures. Here, a model which explains this difference is presented. The model suggests that, due to a higher affinity of ethanol for the hydrophobic surface, when compared to water, a phase separation occurs when a mixture of both liquids is in contact with the H-terminated diamond surface. These results are supported by a computational study giving insight in the affinity and related interaction at the liquid-solid interface.

Impact of surface nanostructure on ice nucleation.

PubMed

Zhang, Xiang-Xiong; Chen, Min; Fu, Ming

2014-09-28

Nucleation of water on solid surface can be promoted noticeably when the lattice parameter of a surface matches well with the ice structure. However, the characteristic length of the surface lattice reported is generally less than 0.5 nm and is hardly tunable. In this paper, we show that a surface with nanoscale roughness can also remarkably promote ice nucleation if the characteristic length of the surface structure matches well with the ice crystal. A series of surfaces composed of periodic grooves with same depth but different widths are constructed in molecular dynamics simulations. Water cylinders are placed on the constructed surfaces and frozen at constant undercooling. The nucleation rates of the water cylinders are calculated in the simulation using the mean first-passage time method and then used to measure the nucleation promotion ability of the surfaces. Results suggest that the nucleation behavior of the supercooled water is significantly sensitive to the width of the groove. When the width of the groove matches well with the specific lengths of the ice crystal structure, the nucleation can be promoted remarkably. If the width does not match with the ice crystal, this kind of promotion disappears and the nucleation rate is even smaller than that on the smooth surface. Simulations also indicate that even when water molecules are adsorbed onto the surface structure in high-humidity environment, the solid surface can provide promising anti-icing ability as long as the characteristic length of the surface structure is carefully designed to avoid geometric match.

Contamination levels of human pharmaceutical compounds in French surface and drinking water.

PubMed

Mompelat, S; Thomas, O; Le Bot, B

2011-10-01

The occurrence of 20 human pharmaceutical compounds and metabolites from 10 representative therapeutic classes was analysed from resource and drinking water in two catchment basins located in north-west France. 98 samples were analysed from 63 stations (surface water and drinking water produced from surface water). Of the 20 human pharmaceutical compounds selected, 16 were quantified in both the surface water and drinking water, with 22% of the values above the limit of quantification for surface water and 14% for drinking water). Psychostimulants, non-steroidal anti-inflammatory drugs, iodinated contrast media and anxiolytic drugs were the main therapeutic classes of human pharmaceutical compounds detected in the surface water and drinking water. The results for surface water were close to results from previous studies in spite of differences in prescription rates of human pharmaceutical compounds in different countries. The removal rate of human pharmaceutical compounds at 11 water treatment units was also determined. Only caffeine proved to be resistant to drinking water treatment processes (with a minimum rate of 5%). Other human pharmaceutical compounds seemed to be removed more efficiently (average elimination rate of over 50%) by adsorption onto activated carbon and oxidation/disinfection with ozone or chlorine (not taking account of the disinfection by-products). These results add to the increasing evidence of the occurrence of human pharmaceutical compounds in drinking water that may represent a threat to human beings exposed to a cocktail of human pharmaceutical compounds and related metabolites and by-products in drinking water.

Recent advances in understanding the interaction of groundwater and surface water

USGS Publications Warehouse

Winter, Thomas C.

1995-01-01

The most common image of the interaction of groundwater and surface water is that of the interaction of streams with a contiguous alluvial aquifer. This type of system has been the focus of study for more than 100 years, from the work of Boussinesq (1877) to the present, and stream-aquifer interaction continues to be the most common topic of papers discussing the interaction of groundwater and surface water. However, groundwater and surface water interact in a wide variety of landscapes from alpine to coastal. Within these landscapes, ground-water systems range in scale from local to regional, and the types of surface water include streams, lakes, wetlands, and oceans. Given the broad spectrum of the topic of groundwater and surface water interaction, an overview of studies of this topic could be organized according to surface water type, landscape type, scale of hydrologic systems, or field and analytical methods. All these factors are discussed, but this paper is organized according to landscape type because of the great increase in studies of the interaction of groundwater and surface water in landscapes other than riverine systems in the last 15 years. Furthermore, discussing studies by landscape type facilitates comparison of methods and results from different geologic and climatic settings. The general landscapes discussed are mountain terrane, riverine systems, coastal terrane, hummocky terrane, and karst terrane.

Effect of water table dynamics on land surface hydrologic memory

NASA Astrophysics Data System (ADS)

Lo, Min-Hui; Famiglietti, James S.

2010-11-01

The representation of groundwater dynamics in land surface models has received considerable attention in recent years. Most studies have found that soil moisture increases after adding a groundwater component because of the additional supply of water to the root zone. However, the effect of groundwater on land surface hydrologic memory (persistence) has not been explored thoroughly. In this study we investigate the effect of water table dynamics on National Center for Atmospheric Research Community Land Model hydrologic simulations in terms of land surface hydrologic memory. Unlike soil water or evapotranspiration, results show that land surface hydrologic memory does not always increase after adding a groundwater component. In regions where the water table level is intermediate, land surface hydrologic memory can even decrease, which occurs when soil moisture and capillary rise from groundwater are not in phase with each other. Further, we explore the hypothesis that in addition to atmospheric forcing, groundwater variations may also play an important role in affecting land surface hydrologic memory. Analyses show that feedbacks of groundwater on land surface hydrologic memory can be positive, negative, or neutral, depending on water table dynamics. In regions where the water table is shallow, the damping process of soil moisture variations by groundwater is not significant, and soil moisture variations are mostly controlled by random noise from atmospheric forcing. In contrast, in regions where the water table is very deep, capillary fluxes from groundwater are small, having limited potential to affect soil moisture variations. Therefore, a positive feedback of groundwater to land surface hydrologic memory is observed in a transition zone between deep and shallow water tables, where capillary fluxes act as a buffer by reducing high-frequency soil moisture variations resulting in longer land surface hydrologic memory.

Effect of a surface tension gradient on the slip flow along a superhydrophobic air-water interface

NASA Astrophysics Data System (ADS)

Song, Dong; Song, Baowei; Hu, Haibao; Du, Xiaosong; Du, Peng; Choi, Chang-Hwan; Rothstein, Jonathan P.

2018-03-01

Superhydrophobic surfaces have been shown to produce significant drag reduction in both laminar and turbulent flows by introducing an apparent slip velocity along an air-water interface trapped within the surface roughness. In the experiments presented within this study, we demonstrate the existence of a surface tension gradient associated with the resultant Marangoni flow along an air-water interface that causes the slip velocity and slip length to be significantly reduced. In this study, the slip velocity along a millimeter-sized air-water interface was investigated experimentally. This large-scale air-water interface facilitated a detailed investigation of the interfacial velocity profiles as the flow rate, interfacial curvature, and interface geometry were varied. For the air-water interfaces supported above continuous grooves (concentric rings within a torsional shear flow) where no surface tension gradient exists, a slip velocity as high as 30% of the bulk velocity was observed. However, for the air-water interfaces supported above discontinuous grooves (rectangular channels in a Poiseuille flow), the presence of a surface tension gradient reduced the slip velocity and in some cases resulted in an interfacial velocity that was opposite to the main flow direction. The curvature of the air-water interface in the spanwise direction was found to dictate the details of the interfacial flow profile with reverse flow in the center of the interface for concave surfaces and along the outside of the interface for convex surfaces. The deflection of the air-water interface was also found to greatly affect the magnitude of the slip. Numerical simulations imposed with a relatively small surface tension gradient along the air-water interface were able to predict both the reduced slip velocity and back flow along the air-water interface.

Potentiometric Surface of the Ozark Aquifer in Northern Arkansas, 2007

USGS Publications Warehouse

Pugh, Aaron L.

2008-01-01

The Ozark aquifer in northern Arkansas is composed of dolomite, limestone, sandstone, and shale of Late Cambrian to Middle Devonian age, and ranges in thickness from approximately 1,100 feet to more than 4,000 feet. Hydrologically, the aquifer is complex, characterized by discrete and discontinuous flow components with large variations in permeability. The potentiometric-surface map, based on 58 well and 5 spring water-level measurements collected in 2007 in Arkansas and Missouri, has a maximum water-level altitude measurement of 1,169 feet in Carroll County and a minimum water-level altitude measurement of 118 feet in Randolph County. Regionally, the flow within the aquifer is to the south and southeast in the eastern and central part of the study area and to the west, northwest, and north in the western part of the study area. Comparing the 2007 potentiometric-surface map with a predevelopment potentiometric-surface map indicates general agreement between the two surfaces except in the northwestern part of the study area. Potentiometric-surface differences can be attributed to withdrawals related to increasing population, changes in public-supply sources, processes or water withdrawals outside the study area, or differences in data-collection or map-construction methods. The rapidly increasing population within the study area appears to have some effect on ground-water levels. Although, the effect appears to have been minimized by the development and use of surface-water distribution infrastructure, suggesting most of the incoming populations are fulfilling their water needs from surface-water sources. The conversion of some users from ground water to surface water may be allowing water levels in wells to recover (rise) or decline at a slower rate, such as in Benton, Carroll, and Washington Counties.

Robust and Superhydrophobic Surface Modification by a "Paint + Adhesive" Method: Applications in Self-Cleaning after Oil Contamination and Oil-Water Separation.

PubMed

Chen, Baiyi; Qiu, Jianhui; Sakai, Eiichi; Kanazawa, Nobuhiro; Liang, Ruilu; Feng, Huixia

2016-07-13

Conventional superhydrophobic surfaces have always depended on expensive, sophisticated, and fragile roughness structures. Therefore, poor robustness has turned into the bottleneck for large-scale industrial applications of the superhydrophobic surfaces. To handle this problem, a superhydrophobic surface with firm robustness urgently needs to be developed. In this work, we created a versatile strategy to fabricate robust, self-cleaning, and superhydrophobic surfaces for both soft and hard substrates. We created an ethanol based suspension of perfluorooctyltriethoxysilane-mdodified calcium carbonate nanoparticles which can be sprayed onto both hard and soft substrates to form superhydrophobic surfaces. For all kinds of substrates, spray adhesive was directly coated onto abluent substrate surfaces to promote the robustness. These superhydrophobic surfaces showed remarkable robustness against knife scratch and sandpaper abrasion, while retaining its superhydrophobicity even after 30 abrasion cycles with sandpaper. What is more, the superhydrophobic surfaces have shown promising potential applications in self-cleaning and oil-water separation. The surfaces retained their self-cleaning property even immersed in oil. In addition to oil-water separation, the water contents in oil after separation of various mixtures were all below 150 ppm, and for toluene even as low as 55 ppm. Furthermore, the as-prepared device for oil-water separation could be cycled 6 times and still retained excellent oil-water separation efficiency.

Climate change and water table fluctuation: Implications for raised bog surface variability

NASA Astrophysics Data System (ADS)

Taminskas, Julius; Linkevičienė, Rita; Šimanauskienė, Rasa; Jukna, Laurynas; Kibirkštis, Gintautas; Tamkevičiūtė, Marija

2018-03-01

Cyclic peatland surface variability is influenced by hydrological conditions that highly depend on climate and/or anthropogenic activities. A low water level leads to a decrease of peatland surface and an increase of C emissions into the atmosphere, whereas a high water level leads to an increase of peatland surface and carbon sequestration in peatlands. The main aim of this article is to evaluate the influence of hydrometeorological conditions toward the peatland surface and its feedback toward the water regime. A regional survey of the raised bog water table fluctuation and surface variability was made in one of the largest peatlands in Lithuania. Two appropriate indicators for different peatland surface variability periods (increase and decrease) were detected. The first one is an 200 mm y- 1 average net rainfall over a three-year range. The second one is an average annual water depth of 25-30 cm. The application of these indicators enabled the reconstruction of Čepkeliai peatland surface variability during a 100 year period. Processes of peatland surface variability differ in time and in separate parts of peatland. Therefore, internal subbasins in peatland are formed. Subbasins involve autogenic processes that can later affect their internal hydrology, nutrient status, and vegetation succession. Internal hydrological conditions, surface fluctuation, and vegetation succession in peatland subbasins should be taken into account during evaluation of their state, nature management projects, and other peatland research works.

Quality-control results for ground-water and surface-water data, Sacramento River Basin, California, National Water-Quality Assessment, 1996-1998

USGS Publications Warehouse

Munday, Cathy; Domagalski, Joseph L.

2003-01-01

Evaluating the extent that bias and variability affect the interpretation of ground- and surface-water data is necessary to meet the objectives of the National Water-Quality Assessment (NAWQA) Program. Quality-control samples used to evaluate the bias and variability include annual equipment blanks, field blanks, field matrix spikes, surrogates, and replicates. This report contains quality-control results for the constituents critical to the ground- and surface-water components of the Sacramento River Basin study unit of the NAWQA Program. A critical constituent is one that was detected frequently (more than 50 percent of the time in blank samples), was detected at amounts exceeding water-quality standards or goals, or was important for the interpretation of water-quality data. Quality-control samples were collected along with ground- and surface-water samples during the high intensity phase (cycle 1) of the Sacramento River Basin NAWQA beginning early in 1996 and ending in 1998. Ground-water field blanks indicated contamination of varying levels of significance when compared with concentrations detected in environmental ground-water samples for ammonia, dissolved organic carbon, aluminum, and copper. Concentrations of aluminum in surface-water field blanks were significant when compared with environmental samples. Field blank samples collected for pesticide and volatile organic compound analyses revealed no contamination in either ground- or surface-water samples that would effect the interpretation of environmental data, with the possible exception of the volatile organic compound trichloromethane (chloroform) in ground water. Replicate samples for ground water and surface water indicate that variability resulting from sample collection, processing, and analysis was generally low. Some of the larger maximum relative percentage differences calculated for replicate samples occurred between samples having lowest absolute concentration differences and(or) values near the reporting limit. Surrogate recoveries for pesticides analyzed by gas chromatography/mass spectrometry (GC/MS), pesticides analyzed by high performance liquid chromatography (HPLC), and volatile organic compounds in ground- and surface-water samples were within the acceptable limits of 70 to 130 percent and median recovery values between 82 and 113 percent. The recovery percentages for surrogate compounds analyzed by HPLC had the highest standard deviation, 20 percent for ground-water samples and 16 percent for surface-water samples, and the lowest median values, 82 percent for ground-water samples and 91 percent for surface-water samples. Results were consistent with the recovery results described for the analytical methods. Field matrix spike recoveries for pesticide compounds analyzed using GC/MS in ground- and surface-water samples were comparable with published recovery data. Recoveries of carbofuran, a critical constituent in ground- and surface-water studies, and desethyl atrazine, a critical constituent in the ground-water study, could not be calculated because of problems with the analytical method. Recoveries of pesticides analyzed using HPLC in ground- and surface-water samples were generally low and comparable with published recovery data. Other methodological problems for HPLC analytes included nondetection of the spike compounds and estimated values of spike concentrations. Recovery of field matrix spikes for volatile organic compounds generally were within the acceptable range, 70 and 130 percent for both ground- and surface-water samples, and median recoveries from 62 to 127 percent. High or low recoveries could be related to errors in the field, such as double spiking or using spike solution past its expiration date, rather than problems during analysis. The methodological changes in the field spike protocol during the course of the Sacramento River Basin study, which included decreasing the amount of spike solu

40 CFR 258.27 - Surface water requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 26 2012-07-01 2011-07-01 true Surface water requirements. 258.27... FOR MUNICIPAL SOLID WASTE LANDFILLS Operating Criteria § 258.27 Surface water requirements. MSWLF... wetlands, that violates any requirements of the Clean Water Act, including, but not limited to, the...

40 CFR 258.27 - Surface water requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

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

40 CFR 258.27 - Surface water requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Surface water requirements. 258.27... 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, the...

Low temperature self-cleaning properties of superhydrophobic surfaces

NASA Astrophysics Data System (ADS)

Wang, Fajun; Shen, Taohua; Li, Changquan; Li, Wen; Yan, Guilong

2014-10-01

Outdoor surfaces are usually dirty surfaces. Ice accretion on outdoor surfaces could lead to serious accidents. In the present work, the superhydrophobic surface based on 1H, 1H, 2H, 2H-Perfluorodecanethiol (PFDT) modified Ag/PDMS composite was prepared to investigate the anti-icing property and self-cleaning property at temperatures below freezing point. The superhydrophobic surface was deliberately polluted with activated carbon before testing. It was observed that water droplet picked up dusts on the cold superhydrophobic surface and took it away without freezing at a measuring temperature of -10 °C. While on a smooth PFDT surface and a rough surface base on Ag/PDMS composite without PFDT modification, water droplets accumulated and then froze quickly at the same temperature. However, at even lower temperature of -12 °C, the superhydrophobic surface could not prevent the surface water from icing. In addition, it was observed that the frost layer condensed from the moisture pay an important role in determining the low temperature self-cleaning properties of a superhydrophobic surface.

Surface Forces Apparatus Measurements of Interactions between Rough and Reactive Calcite Surfaces.

PubMed

Dziadkowiec, Joanna; Javadi, Shaghayegh; Bratvold, Jon E; Nilsen, Ola; Røyne, Anja

2018-06-26

nm-Range forces acting between calcite surfaces in water affect macroscopic properties of carbonate rocks and calcite-based granular materials and are significantly influenced by calcite surface recrystallization. We suggest that the repulsive mechanical effects related to nm-scale surface recrystallization of calcite in water could be partially responsible for the observed decrease of cohesion in calcitic rocks saturated with water. Using the surface forces apparatus, we simultaneously followed the calcite reactivity and measured the forces in water in two surface configurations: between two rough calcite surfaces (CC) and between rough calcite and a smooth mica surface (CM). We used nm-scale rough, polycrystalline calcite films prepared by atomic layer deposition. We measured only repulsive forces in CC in CaCO 3 -saturated water, which was related to roughness and possibly to repulsive hydration effects. Adhesive or repulsive forces were measured in CM in CaCO 3 -saturated water depending on calcite roughness, and the adhesion was likely enhanced by electrostatic effects. The pull-off adhesive force in CM became stronger with time, and this increase was correlated with a decrease of roughness at contacts, the parameter which could be estimated from the measured force-distance curves. That suggested a progressive increase of real contact areas between the surfaces, caused by gradual pressure-driven deformation of calcite surface asperities during repeated loading-unloading cycles. Reactivity of calcite was affected by mass transport across nm- to μm-thick gaps between the surfaces. Major roughening was observed only for the smoothest calcite films, where gaps between two opposing surfaces were nm-thick over μm-sized areas and led to force of crystallization that could overcome confining pressures of the order of MPa. Any substantial roughening of calcite caused a significant increase of the repulsive mechanical force contribution.

Herbicide Metabolites in Surface Water and Groundwater: Introduction and Overview

USGS Publications Warehouse

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

1996-01-01

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

Fabrication and condensation characteristics of metallic superhydrophobic surface with hierarchical micro-nano structures

NASA Astrophysics Data System (ADS)

Chu, Fuqiang; Wu, Xiaomin

2016-05-01

Metallic superhydrophobic surfaces have various applications in aerospace, refrigeration and other engineering fields due to their excellent water repellent characteristics. This study considers a simple but widely applicable fabrication method using a two simultaneous chemical reactions method to prepare the acid-salt mixed solutions to process the metal surfaces with surface deposition and surface etching to construct hierarchical micro-nano structures on the surface and then modify the surface with low surface-energy materials. Al-based and Cu-based superhydrophobic surfaces were fabricated using this method. The Al-based superhydrophobic surface had a water contact angle of 164° with hierarchical micro-nano structures similar to the lotus leaves. The Cu-based surface had a water contact angle of 157° with moss-like hierarchical micro-nano structures. Droplet condensation experiments were also performed on these two superhydrophobic surfaces to investigate their condensation characteristics. The results show that the Al-based superhydrophobic surface has lower droplet density, higher droplet jumping probability, slower droplet growth rate and lower surface coverage due to the more structured hierarchical structures.

Mechanisms of surface runoff genesis on a subsurface drained soil affected by surface crusting: A field investigation

NASA Astrophysics Data System (ADS)

Augeard, Bénédicte; Kao, Cyril; Chaumont, Cédric; Vauclin, Michel

Artificial drainage has been subject to widespread criticism because of its impact on water quality and because there is suspicion that it may have detrimental effects on flood genesis. The present work aims at a better understanding of the mechanisms controlling infiltration and surface runoff genesis, particularly in soils with artificial drainage and affected by surface crusting. A field experiment was conducted during one drainage season (November 2003-March 2004) in the Brie region (80 km east of Paris, France) on a subsurface drained silty soil. Water table elevation and surface runoff were monitored above the drain and at midpoint between drains. Soil water pressure head was measured at various depths and locations between the midpoint and the drain. Soil surface characteristics (microtopography and degree of structural and sedimentary crust development) were recorded regularly on the experimental site and on other plots of various drainage intensities. The results show that the first surface runoff events were induced by high water table. However, runoff was higher at midpoint between the drains because water table reached the soil surface at that point, thus considerably reducing infiltration capacity compared to that above the drain. Comparing different plots, the area with older drainage installation (1948) yielded the most surface runoff. Wider drain spacing, smaller drain depth and possible plugging may have led to a greater area of saturated soil between drains. During the winter period, the impact of raindrops induced the formation of a structural crust on the soil surface. Furthermore, the development of the sedimentary crust, which was favored by water actually flowing on the soil surface during the high water table periods could be correlated with surface runoff volume. The formation of this crust had a significant impact on runoff occurrence at the end of the winter. Therefore, poorly drained fields presented more favorable conditions for both Horton type runoff and saturation excess runoff. Drainage effectively reduces surface runoff occurrences not only by lowering the water table in winter but also by limiting soil surface sealing.

Analogies to Demonstrate the Effect of Roughness on Surface Wettability

ERIC Educational Resources Information Center

Yolcu, Hasan

2017-01-01

This article presents an analogy to illustrate the effect of surface roughness on surface wettability. I used a water-filled balloon to represent water droplet, a toothpick to represent surface roughness and Styrofoam as the surface. The analogies presented in this article will help visualize how roughness affects the wettability of the surface…

Documentation of programs used to determine a wetlands hydroperiod from model-simulated water-surface elevations

USGS Publications Warehouse

Sonenshein, R.S.

1996-01-01

A technique has been developed to determine a wetlands hydroperiod by comparing simulated water levels from a ground-water flow model and land- surface elevation data through a geographic information system. The simulated water levels are compared with the land-surface elevation data to determine the height of the water surface above or below land surface for the area of interest. Finally, the hydroperiod is determined for established time periods using criteria specified by the user. The program application requires the use of geographic information system software (ARC/INFO), including the TIN and GRID subsystems of the software. The application consists of an ANSI compatible C program to translate ground- water data output from the U.S. Geological Survey modular three-dimensional, finite-difference, ground-water flow model (MODFLOW) into a format that can be used as input for the geographic information system programs (AML's). The application uses ARC/INFO AML programs and ARC/INFO menu interface programs to create digital spatial data layers of the land surface and water surface and to determine the hydroperiod. The technique can be used to evaluate and manage wetlands hydrology.

Oxidation of MnO(100) and NaMnO2 formation: Characterization of Mn2+ and Mn3+ surfaces via XPS and water TPD

NASA Astrophysics Data System (ADS)

Feng, Xu; Cox, David F.

2018-09-01

The oxidation of clean and Na precovered MnO(100) has been investigated by X-ray photoelectron spectroscopy (XPS), low energy electron diffraction (LEED) and temperature programmed desorption (TPD) of adsorbed water. XPS results indicate that Mn3O4-like and Mn2O3-like surfaces can be formed by various oxidation treatments of clean and nearly-stoichiometric MnO(100), while a NaMnO2-like surface can be produced by the oxidation of MnO(100) pre-covered with multilayers of metallic Na. Water TPD results indicate that water adsorption/desorption is sensitive to the available oxidation states of surface Mn cations, and can be used to distinguish between surfaces exposing Mn2+and Mn3+ cations, or a combination of these oxidation states. Carbon dioxide and water TPD results from the NaMnO2-like surface indicate that pre-adsorbed water blocks the uptake of CO2, while water displaces pre-adsorbed CO2. No indication of a strong reactive interaction is observed between CO2, water and the NaMnO2-like surface under the conditions of our study.

Characterizing hydrophobicity at the nanoscale: a molecular dynamics simulation study.

PubMed

Bandyopadhyay, Dibyendu; Choudhury, Niharendu

2012-06-14

We use molecular dynamics (MD) simulations of water near nanoscopic surfaces to characterize hydrophobic solute-water interfaces. By using nanoscopic paraffin like plates as model solutes, MD simulations in isothermal-isobaric ensemble have been employed to identify characteristic features of such an interface. Enhanced water correlation, density fluctuations, and position dependent compressibility apart from surface specific hydrogen bond distribution and molecular orientations have been identified as characteristic features of such interfaces. Tetrahedral order parameter that quantifies the degree of tetrahedrality in the water structure and an orientational order parameter, which quantifies the orientational preferences of the second solvation shell water around a central water molecule, have also been calculated as a function of distance from the plate surface. In the vicinity of the surface these two order parameters too show considerable sensitivity to the surface hydrophobicity. The potential of mean force (PMF) between water and the surface as a function of the distance from the surface has also been analyzed in terms of direct interaction and induced contribution, which shows unusual effect of plate hydrophobicity on the solvent induced PMF. In order to investigate hydrophobic nature of these plates, we have also investigated interplate dewetting when two such plates are immersed in water.

A Facile All-Solution-Processed Surface with High Water Contact Angle and High Water Adhesive Force.

PubMed

Chen, Mei; Hu, Wei; Liang, Xiao; Zou, Cheng; Li, Fasheng; Zhang, Lanying; Chen, Feiwu; Yang, Huai

2017-07-12

A series of sticky superhydrophobicity surfaces with high water contact angle and high water adhesive force is facilely prepared via an all-solution-processed method based on polymerization-induced phase separation between liquid crystals (LCs) and epoxy resin, which produces layers of epoxy microspheres (EMSs) with nanofolds on the surface of a substrate. The morphologies and size distributions of EMSs are confirmed by scanning electron microscopy. Results reveal that the obtained EMS coated-surface exhibits high apparent contact angle of 152.0° and high water adhesive force up to 117.6 μN. By varying the composition of the sample or preparing conditions, the sizes of the produced EMSs can be artificially regulated and, thus, control the wetting properties and water adhesive behaviors. Also, the sticky superhydrophobic surface exhibits excellent chemical stability, as well as long-term durability. Water droplet transportation experiments further prove that the as-made surface can be effectively used as a mechanical hand for water transportation applications. Based on this, it is believed that the simple method proposed in this paper will pave a new way for producing a sticky superhydrophobic surface and obtain a wide range of use.

Groundwater and surface water exchange and resulting Nitrate dynamics in the Bogue Phalia Basin in northwestern Mississippi

USGS Publications Warehouse

Barlow, Jeannie R.; Coupe, Richard H.

2012-01-01

During April 2007 through September 2008, the USGS collected hydrogeologic and water-quality data from a site on the Bogue Phalia to evaluate the role of groundwater and surface-water interaction on the transport of nitrate to the shallow sand and gravel aquifer underlying the Mississippi Alluvial Plain in northwestern Mississippi. A two-dimensional groundwater/surface-water exchange model was developed using temperature and head data and VS2DH, a variably saturated flow and energy transport model. Results from this model showed that groundwater/surface-water exchange at the site occurred regularly and recharge was laterally extensive into the alluvial aquifer. Nitrate was consistently reported in surface-water samples (n = 52, median concentration = 39.8 μmol/L) although never detected in samples collected from in-stream piezometers or shallow monitoring wells adjacent to the stream (n = 46). These two facts, consistent detections of nitrate in surface water and no detections of nitrate in groundwater, coupled with model results that indicate large amounts of surface water moving through an anoxic streambed, support the case for denitrification and nitrate loss through the streambed.

Potentiometric Surface of the Upper Floridan Aquifer in the St. Johns River Water Management District and Vicinity, Florida, May 2007

USGS Publications Warehouse

Kinnaman, Sandra L.; Dixon, Joann F.

2007-01-01

Introduction This map depicts the potentiometric surface of the Upper Floridan aquifer in the St. Johns River Water Management District and vicinity for May 2007. Potentiometric contours are based on water-level measurements collected at 566 wells during the period May 4-June 11 near the end of the dry season, however most of the water level data for this map were collected by the U.S. Geological Survey during the period May 21-25, 2007. Some contours are inferred from previous potentiometric-surface maps with larger well networks. The potentiometric surface of the carbonate Upper Floridan aquifer responds mainly to rainfall, and more locally, to ground-water withdrawals and spring flow. Potentiometric-surface highs generally correspond to topographic highs where the aquifer is recharged. Springs and areas of diffuse upward leakage naturally discharge water from the aquifer and are most prevalent along the St. Johns River. Areas of discharge are reflected by depressions in the potentiometric surface. Ground-water withdrawals locally have lowered the potentiometric surface. Ground water in the Upper Floridan aquifer generally flows from potentiometric highs to potentiometric lows in a direction perpendicular to the contours.

Hydrogeology and ground-water/surface water interactions in the Des Moines River valley, southwestern Minnesota, 1997-2001

USGS Publications Warehouse

Cowdery, Timothy K.

2005-01-01

Long-term withdrawals of water for public supplies may cause a net decrease in ground-water discharge to surface water. Water that does not evaporate, or that is not exported, is discharged to the Des Moines River but with changed water quality. Because ground-water and surface-water qualities in the study area are similar, the ground-water discharge probably has little effect on river water quality.

The effects of large-scale pumping and diversion on the water resources of Dane County, Wisconsin

USGS Publications Warehouse

Hunt, Randall J.; Bradbury, Kenneth R.; Krohelski, James T.

2001-01-01

Throughout many parts of the U.S., there is growing concern over the effects of rapid urban growth and development on water resources. Ground- water and surface-water systems (which comprise the hydrologic system) are linked in much of Wisconsin, and ground water can be utilized both for drinking water and as a source of water for sustaining lakes, streams, springs, and wetlands. Ground water is important for surface-water systems because it commonly has greater dissolved solids and more acid-neutraliz- ing capacity than surface water or precipitation. The supplies of ground water are finite, however, and, in many cases ground water used for one purpose cannot be used for another. Moreover, ground-water use and withdrawal patterns may not be easy to alter once established. Thus, urban and rural planners are faced with decisions that balance the need for ground- water withdrawals while maintaining the quantity and quality of ground water for sustaining surface-water resources. Science-based information on the ground-water system and the connections to surface-water systems provides valuable insight for such decisions.

Sustaining dry surfaces under water

PubMed Central

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

2015-01-01

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

Interaction of poly(ethylene-glycols) with air-water interfaces and lipid monolayers: investigations on surface pressure and surface potential.

PubMed Central

Winterhalter, M; Bürner, H; Marzinka, S; Benz, R; Kasianowicz, J J

1995-01-01

We have characterized the surface activity of different-sized poly(ethylene-glycols) (PEG; M(r) 200-100,000 Da) in the presence or absence of lipid monolayers and over a wide range of bulk PEG concentrations (10(-8)-10% w/v). Measurements of the surface potential and surface pressure demonstrate that PEGs interact with the air-water and lipid-water interfaces. Without lipid, PEG added either to the subphase or to the air-water interface forms relatively stable monolayers. Except for very low molecular weight polymers (PEGs < 1000 Da), low concentrations of PEG in the subphase (between 10(-5) and 10(-4)% w/v) increase the surface potential from zero (with respect to the potential of a pure air-water interface) to a plateau value of approximately 440 mV. At much higher polymer concentrations, > 10(-1)% (w/v), depending on the molecular weight of the PEG and corresponding to the concentration at which the polymers in solution are likely to overlap, the surface potential decreases. High concentrations of PEG in the subphase cause a similar decrease in the surface potential of densely packed lipid monolayers spread from either diphytanoyl phosphatidylcholine (DPhPC), dipalmitoyl phosphatidylcholine (DPPC), or dioleoyl phosphatidylserine (DOPS). Adding PEG as a monolayer at the air-water interface also affects the surface activity of DPhPC or DPPC monolayers. At low lipid concentration, the surface pressure and potential are determined by the polymer. For intermediate lipid concentrations, the surface pressure-area and surface potential-area isotherms show that the effects due to lipid and PEG are not always additive and that the polymer's effect is distinct for the two lipids. When PEG-lipid-mixed monolayers are compressed to surface pressures greater than the collapse pressure for a PEG monolayer, the surface pressure-area and surface potential-area isotherms approach that of the lipid alone, suggesting that for this experimental condition PEG is expelled from the interface. PMID:8534807

Anti-icing properties of superhydrophobic ZnO/PDMS composite coating

NASA Astrophysics Data System (ADS)

Yang, Chao; Wang, Fajun; Li, Wen; Ou, Junfei; Li, Changquan; Amirfazli, Alidad

2016-01-01

We present the excellent anti-icing performance for a superhydrophobic coating surface based on ZnO/polydimethylsiloxane (ZnO/PDMS) composite. The superhydrophobic ZnO/PDMS coating surface was prepared by a facile solution mixing, drop coating, room-temperature curing and surface abrading procedure. The superhydrophobic ZnO/PDMS composite coating possesses a water contact angle of 159.5° and a water sliding angle of 8.3° at room temperature (5 °C). The anti-icing properties of the superhydrophobic coating were investigated by continuously dropping cold-water droplets (about 0 °C) onto the pre-cooled surface using a home-made apparatus. The sample was placed at different tilting angle (0° and 10°) and pre-cooled to various temperatures (-5, -10 and -15 °C) prior to measure. The pure Al surface was also studied for comparison. It was found that icing accretion on the surface could be reduced apparently because the water droplets merged together and slid away from the superhydrophobic surface at all of the measuring temperatures when the surface is horizontally placed. In addition, water droplet slid away completely from the superhydrophobic surface at -5 and -10 °C when the surface is tilted at 10°, which demonstrates its excellent anti-icing properties at these temperatures. When the temperature decreased to -15 °C, though ice accretion on the tilted superhydrophobic coating surface could not be avoided absolutely, the amount of ice formed on the surface is very small, which indicated that the coating surface with superhydrophobicity could significantly reduce ice accumulation on the surface at very low temperature (-15 °C). Importantly, the sample is also stable against repeated icing/deicing cycles. More meaningfully, once the superhydrophobic surface is damaged, it can be repaired easily and rapidly.

Structural and dynamical characterization of water on the Au (100) and graphene surfaces: A molecular dynamics simulation approach

NASA Astrophysics Data System (ADS)

Foroutan, Masumeh; Darvishi, Mehdi; Fatemi, S. Mahmood

2017-09-01

The positioning, adsorption, and movement of water on substrates is dependent upon the chemical nature and arrangement of the atoms of the surface. Therefore the behavior of water molecules on a substrate is a reflection of properties of the surface. Based on this premise, graphene and gold substrates were chosen to study this subject from a molecular perspective. In this work, the structural and dynamical behaviors of a water nanodroplet on Au (100) and the graphene interfaces have been studied by molecular dynamics simulation. The results have shown how the structural and dynamical behaviors of water molecules at the interface reflect the characteristics of these surfaces. The results have demonstrated that residence time and hydrogen bonds' lifetime at the water-Au (100) interface are bigger than at the water-graphene interface. Energy contour map analysis indicates a more uniform surface energy on graphene than on the gold surface. The obtained results illustrate that water clusters on gold and graphene form tetramer and hexamer structures, respectively. Furthermore, the water molecules are more ordered on the gold surface than on graphene. The study of hydrogen bonds showed that the order, stability, and the number of hydrogen bonds is higher on the gold surface. The positioning pattern of water molecules is also similar to the arrangement of gold atoms while no regularity was observed on graphene. The study of dynamical behavior of water molecules revealed that the movement of water on gold is much less than on graphene which is in agreement with the strong water-gold interaction in comparison to the water-graphene interaction.

U.S. Geological Survey quality-assurance plan for surface-water activities in Kansas, 2015

USGS Publications Warehouse

Painter, Colin C.; Loving, Brian L.

2015-01-01

This Surface Water Quality-Assurance Plan documents the standards, policies, and procedures used by the Kansas Water Science Center (KSWSC) of the U.S. Geological Survey (USGS) for activities related to the collection, processing, storage, analysis, and publication of surface-water data.

Role of oxygen functional groups for structure and dynamics of interfacial water on low rank coal surface: a molecular dynamics simulation

NASA Astrophysics Data System (ADS)

You, Xiaofang; Wei, Hengbin; Zhu, Xianchang; Lyu, Xianjun; Li, Lin

2018-07-01

Molecular dynamics simulations were employed to study the effects of oxygen functional groups for structure and dynamics properties of interfacial water molecules on the subbituminous coal surface. Because of complex composition and structure, the graphite surface modified by hydroxyl, carboxyl and carbonyl groups was used to represent the surface model of subbituminous coal according to XPS results, and the composing proportion for hydroxyl, carbonyl and carboxyl is 25:3:5. The hydration energy with -386.28 kJ/mol means that the adsorption process between water and coal surface is spontaneous. Density profiles for oxygen atoms and hydrogen atoms indicate that the coal surface properties affect the structural and dynamic characteristics of the interfacial water molecules. The interfacial water exhibits much more ordering than bulk water. The results of radial distribution functions, mean square displacement and local self-diffusion coefficient for water molecule related to three oxygen moieties confirmed that the water molecules prefer to absorb with carboxylic groups, and adsorption of water molecules at the hydroxyl and carbonyl is similar.

Surface wastewater in Samara and their impact on water basins as water supply sources

NASA Astrophysics Data System (ADS)

Strelkov, Alexander; Shuvalov, Mikhail; Gridneva, Marina

2017-10-01

The paper gives an overview of surface wastewater outlets in Samara through the rainwater sewer system into the Saratov water reservoir and the Samara river. The rainwater sewer system in Samara is designed and executed according to a separate scheme, except for the old part of the city, where surface run-off is dumped into the sewer system through siphoned drain. The rainwater system disposes of surface, drainage, industrial clean-contamined waters, emergency and technology discharges from the city’s heat supply and water supply systems. The effluent discharge is carried out by means of separate wastewater outlets into ravines or directly into the Samara river and the Saratov water reservoir without cleaning. The effluent discharge is carried out through the rainwater sewer system with 17 wastewater outlets into the Saratov water reservoir. In the Samara river, surface runoff drainage and clean-contamined water of industrial enterprises is carried out through 14 wastewater outlets. This study emphasizes the demand to arrange effluent discharge and construction of sewage treatment plants to prevent contamination of water objects by surface run-off from residential areas and industrial territories.

Tritium migration to the surfaces of Type 316 stainless steel; aluminum 6061; and oxygen-free, high-conductivity copper

DOE PAGES

Sharpe, M.; Shmayda, W. T.; Schroder, W. U.

2016-05-25

The migration of tritium to the surfaces of aluminum 6061, oxygen-free, high-conductivity copper (OFHC), and stainless-steel 316 from the bulk metal was studied using low-pressure Tonks–Langmuir argon plasma. The plasma is shown to be effective at removing tritium from metal surfaces in a controlled manner. Tritium is removed in decreasing quantities with successive plasma exposures, which suggests a depletion of the surface and near-surface tritium inventories. A diffusion model was developed to predict tritium migration from the bulk and its accumulation in the water layers present on the metal surface. The model reproduces the rate of tritium re-growth on themore » surface for all three metals and can be used to calculate the triton solubility in the water layers present on metal surfaces. The ratio of surface-to-bulk solubilities at the water-layer/bulk-metal interface uniquely determines the concentration ratio between these two media. Removing the tritium-rich water layers induces tritium to migrate from the bulk to the surface. Furthermore, this process is driven by a concentration gradient that develops in the bulk because of the perturbation on the surface.« less

Pepper mild mottle virus as an indicator and a tracer of fecal pollution in water environments: comparative evaluation with wastewater-tracer pharmaceuticals in Hanoi, Vietnam.

PubMed

Kuroda, Keisuke; Nakada, Norihide; Hanamoto, Seiya; Inaba, Manami; Katayama, Hiroyuki; Do, An Thuan; Nga, Tran Thi Viet; Oguma, Kumiko; Hayashi, Takeshi; Takizawa, Satoshi

2015-02-15

We analyzed pepper mild mottle virus (PMMoV) in 36 samples taken from surface water, wastewater, groundwater, tap water and bottled water in Hanoi, Vietnam. We then compared the occurrence and fates of PMMoV with pharmaceuticals and personal care products (PPCPs), which are known wastewater tracers. PMMoV was detected in 94% of the surface water samples (ponds, water from irrigated farmlands and rivers) and in all the wastewater samples. The PMMoV concentration ranged from 5.5×10(6)-7.2×10(6)copies/L in wastewater treatment plant (WWTP) influents, 6.5×10(5)-8.5×10(5)copies/L in WWTP effluents and 1.0×10(4)-1.8×10(6)copies/L in surface water. Among the sixty PPCPs analyzed, caffeine and carbamazepine had high detection rates in surface water (100% and 88%, respectively). In surface water, the concentration ratio of PMMoV to caffeine remained unchanged than that in WWTP influents, suggesting that the persistence of PMMoV in surface water was comparable to that of caffeine. The persistence and the large concentration ratio of PMMoV in WWTP influents to the method detection limit would account for its ubiquitous detection in surface water. In comparison, human enteric viruses (HEV) were less frequently detected (18-59%) than PMMoV in surface water, probably because of their faster decay. Together with the reported high human feces-specificity, our results suggested that PMMoV is useful as a sensitive fecal indicator for evaluating the potential occurrence of pathogenic viruses in surface water. Moreover, PMMoV can be useful as a moderately conservative fecal tracer for specifically tracking fecal pollution of surface water. PMMoV was detected in 38% of the groundwater samples at low concentrations (up to 19copies/L). PMMoV was not detected in the tap water and bottled water samples. In groundwater, tap water and bottled water samples, the occurrence of PPCPs and HEV disagreed with that of PMMoV, suggesting that PMMoV is not suitable as an indicator or a tracer in those waters. Copyright © 2014 Elsevier B.V. All rights reserved.

Peeling the astronomical onion.

PubMed

Rosu-Finsen, Alexander; Marchione, Demian; Salter, Tara L; Stubbing, James W; Brown, Wendy A; McCoustra, Martin R S

2016-11-23

Water ice is the most abundant solid in the Universe. Understanding the formation, structure and multiplicity of physicochemical roles for water ice in the cold, dense interstellar environments in which it is predominantly observed is a crucial quest for astrochemistry as these are regions active in star and planet formation. Intuitively, we would expect the mobility of water molecules deposited or synthesised on dust grain surfaces at temperatures below 50 K to be very limited. This work delves into the thermally-activated mobility of H 2 O molecules on model interstellar grain surfaces. The energy required to initiate this process is studied by reflection-absorption infrared spectroscopy of small quantities of water on amorphous silica and highly oriented pyrolytic graphite surfaces as the surface is annealed. Strongly non-Arrhenius behaviour is observed with an activation energy of 2 kJ mol -1 on the silica surface below 25 K and 0 kJ mol -1 on both surfaces between 25 and 100 K. The astrophysical implication of these results is that on timescales shorter than that estimated for the formation of a complete monolayer of water ice on a grain, aggregation of water ice will result in a non-uniform coating of water, hence leaving bare grain surface exposed. Other molecules can thus be formed or adsorbed on this bare surface.

Measurements of slip length for flows over graphite surface with gas domains

NASA Astrophysics Data System (ADS)

Li, Dayong; Wang, Yuliang; Pan, Yunlu; Zhao, Xuezeng

2016-10-01

We present the measurements of slip lengths for the flows of purified water over graphite surface covered with surface nanobubbles or nano/micropancakes, which can be produced after using high temperature water to replace low temperature water. The slip length values measured on bare graphite surface, nano/micropancake or nanobubble covered graphite surfaces are about 8 nm, 27 nm, and 63 nm, respectively. Our results indicate that the gaseous domains formed at the solid-liquid interface, including surface nanobubbles and nano/micropancakes, could act as a lubricant and significantly increase slip length.

Free energy of adhesion of lipid bilayers on silica surfaces

NASA Astrophysics Data System (ADS)

Schneemilch, M.; Quirke, N.

2018-05-01

The free energy of adhesion per unit area (hereafter referred to as the adhesion strength) of lipid arrays on surfaces is a key parameter that determines the nature of the interaction between materials and biological systems. Here we report classical molecular simulations of water and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) lipid bilayers at model silica surfaces with a range of silanol densities and structures. We employ a novel technique that enables us to estimate the adhesion strength of supported lipid bilayers in the presence of water. We find that silanols on the silica surface form hydrogen bonds with water molecules and that the water immersion enthalpy for all surfaces varies linearly with the surface density of these hydrogen bonds. The adhesion strength of lipid bilayers is a linear function of the surface density of hydrogen bonds formed between silanols and the lipid molecules on crystalline surfaces. Approximately 20% of isolated silanols form such bonds but more than 99% of mutually interacting geminal silanols do not engage in hydrogen bonding with water. On amorphous silica, the bilayer displays much stronger adhesion than expected from the crystalline surface data. We discuss the implications of these results for nanoparticle toxicity.

A global, 30-m resolution land-surface water body dataset for 2000

NASA Astrophysics Data System (ADS)

Feng, M.; Sexton, J. O.; Huang, C.; Song, D. X.; Song, X. P.; Channan, S.; Townshend, J. R.

2014-12-01

Inland surface water is essential to terrestrial ecosystems and human civilization. The distribution of surface water in space and its change over time are related to many agricultural, environmental and ecological issues, and are important factors that must be considered in human socioeconomic development. Accurate mapping of surface water is essential for both scientific research and policy-driven applications. Satellite-based remote sensing provides snapshots of Earth's surface and can be used as the main input for water mapping, especially in large areas. Global water areas have been mapped with coarse resolution remotely sensed data (e.g., the Moderate Resolution Imaging Spectroradiometer (MODIS)). However, most inland rivers and water bodies, as well as their changes, are too small to map at such coarse resolutions. Landsat TM (Thematic Mapper) and ETM+ (Enhanced Thematic Mapper Plus) imagery has a 30m spatial resolution and provides decades of records (~40 years). Since 2008, the opening of the Landsat archive, coupled with relatively lower costs associated with computing and data storage, has made comprehensive study of the dynamic changes of surface water over large even global areas more feasible. Although Landsat images have been used for regional and even global water mapping, the method can hardly be automated due to the difficulties on distinguishing inland surface water with variant degrees of impurities and mixing of soil background with only Landsat data. The spectral similarities to other land cover types, e.g., shadow and glacier remnants, also cause misidentification. We have developed a probabilistic based automatic approach for mapping inland surface water bodies. Landsat surface reflectance in multiple bands, derived water indices, and data from other sources are integrated to maximize the ability of identifying water without human interference. The approach has been implemented with open-source libraries to facilitate processing large amounts of Landsat images on high-performance computing machines. It has been applied to the ~9,000 Landsat scenes of the Global Land Survey (GLS) 2000 data collection to produce a global, 30m resolution inland surface water body data set, which will be made available on the Global Land Cover Facility (GLCF) website (http://www.landcover.org).

Development of Biomimetic and Functionally Responsive Surfaces

NASA Astrophysics Data System (ADS)

Anastasiadis, Spiros H.

2010-03-01

Controlling the surface morphology of solids and manufacturing of functional surfaces with special responsive properties has been the subject of intense research. We report a methodology for creating multifunctionally responsive surfaces by irradiating silicon wafers with femtosecond laser pulses and subsequently coating them with different types of functional conformal coatings. Such surfaces exhibit controlled dual-scale roughness at the micro- and the nano-scale, which mimics the hierarchical morphology of water repellent natural surfaces. When a simple alkylsilane coating is utilized, highly water repellent surfaces are produced that quantitatively compare to those of the Lotus leaf. When a polymer brush is ``grafted from" these surfaces based on a pH-sensitive polymer, the surfaces can alter their behavior from super-hydrophilic (after immersion in a low pH buffer) to super-hydrophobic and water-repellent (following immersion to a high pH buffer). We quantify the water repellency of such responsive systems by drop elasticity measurements whereas we demonstrate that the water repellent state of such surface requires appropriate hydrophobicity of the functionalizing polymer. When a photo-responsive azobenzene-type polymer is deposited, a dynamic optical control of the wetting properties is obtained and the surface can be switched from super-hydrophilic (following UV irradiation) to hydrophobic (following green irradiation). In all the above cases we show that the principal effect of roughness is to cause amplification of the response to the different external stimuli.

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

USGS Publications Warehouse

Rosenberry, Donald O.; LaBaugh, James W.

2008-01-01

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

Ground-water/surface-water interaction in nearshore areas of Three Lakes on the Grand Portage Reservation, northeastern Minnesota, 2003-04

USGS Publications Warehouse

Jones, Perry M.

2006-01-01

Knowledge of general water-flow directions in lake watersheds and how they may change seasonally can help water-quality specialists and lake managers address a variety of water-quality and aquatic habitat protection issues for lakes. Results from this study indicate that ground-water and surface-water interactions at the study lakes are complex, and the ability of the applied techniques to identify ground-water inflow and surface-water outseepage locations varied among the lakes. Measurement of lake-sediment temperatures proved to be a reliable and relatively inexpensive reconnaissance technique that lake managers may apply in complex settings to identify general areas of ground-water inflow and surface-water outseepage.

Influence of LaFeO 3 Surface Termination on Water Reactivity

DOE PAGES

Stoerzinger, Kelsey A.; Comes, Ryan; Spurgeon, Steven R.; ...

2017-02-16

The polarity of oxide surfaces can dramatically impact their surface reactivity, in particular, with polar molecules such as water. The surface species that result from this interaction change the oxide electronic structure and chemical reactivity in applications such as photoelectrochemistry but are challenging to probe experimentally. Here, we report a detailed study of the surface chemistry and electronic structure of the perovskite LaFeO 3 in humid conditions using ambient-pressure X-ray photoelectron spectroscopy. In comparing the two possible terminations of the polar (001)-oriented surface, we find that the LaO-terminated surface is more reactive toward water, forming hydroxyl species and adsorbing molecularmore » water at lower relative humidity than its FeO 2-terminated counterpart. But, the FeO 2-terminated surface forms more hydroxyl species during water adsorption at higher humidity, suggesting that adsorbate–adsorbate interactions may impact reactivity. These results demonstrate how the termination of a complex oxide can dramatically impact its reactivity, providing insight that can aid in the design of catalyst materials.« less

Influence of LaFeO 3 Surface Termination on Water Reactivity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stoerzinger, Kelsey A.; Comes, Ryan; Spurgeon, Steven R.

The polarity of oxide surfaces can dramatically impact their surface reactivity, in particular, with polar molecules such as water. The surface species that result from this interaction change the oxide electronic structure and chemical reactivity in applications such as photoelectrochemistry but are challenging to probe experimentally. Here, we report a detailed study of the surface chemistry and electronic structure of the perovskite LaFeO 3 in humid conditions using ambient-pressure X-ray photoelectron spectroscopy. In comparing the two possible terminations of the polar (001)-oriented surface, we find that the LaO-terminated surface is more reactive toward water, forming hydroxyl species and adsorbing molecularmore » water at lower relative humidity than its FeO 2-terminated counterpart. But, the FeO 2-terminated surface forms more hydroxyl species during water adsorption at higher humidity, suggesting that adsorbate–adsorbate interactions may impact reactivity. These results demonstrate how the termination of a complex oxide can dramatically impact its reactivity, providing insight that can aid in the design of catalyst materials.« less

Mechanically durable underwater superoleophobic surfaces based on hydrophilic bulk metals for oil/water separation

NASA Astrophysics Data System (ADS)

Yu, Huadong; Lian, Zhongxu; Xu, Jinkai; Wan, Yanling; Wang, Zuobin; Li, Yiquan; Yu, Zhanjiang; Weng, Zhankun

2018-04-01

Despite the success of previous methods for fabricating underwater superoleophobic surfaces, most of the surfaces based on soft materials are prone to collapse and deformation due to their mechanically fragile nature, and they fail to perform their designed functions after the surface materials are damaged in water. In this work, the nanosecond laser-induced oxide coatings on hydrophilic bulk metals are reported which overcomes the limitation and shows the robust underwater superoleophobicity to a mechanical challenge encountered by surfaces deployed in water environment. The results show that the surface materials have the advantage that the underwater superoleophobicity is still preserved after the surfaces are scratched by knife or sandpaper and even completely destroyed because of the hydrophilic property of damaged materials in water. It is important that the results provide a guide for the design of durable underwater superoleophobic surfaces, and the development of superoleophobic materials in many potential applications such as the oil-repellent and the oil/water separation. Additionally, the nanosecond laser technology is simple, cost-effective and suitable for the large-area and mass fabrication of mechanically durable underwater superoleophobic metal materials.

A quantum mechanical study of water adsorption on the (110) surfaces of rutile SnO₂ and TiO₂: investigating the effects of intermolecular interactions using hybrid-exchange density functional theory.

PubMed

Patel, M; Sanches, F F; Mallia, G; Harrison, N M

2014-10-21

Periodic hybrid-exchange density functional theory calculations are used to explore the first layer of water at model oxide surfaces, which is an important step for understanding the photocatalytic reactions involved in solar water splitting. By comparing the structure and properties of SnO2(110) and TiO2(110) surfaces in contact with water, the effects of structural and electronic differences on the water chemistry are examined. The dissociative adsorption mode at low coverage (1/7 ML) up to monolayer coverage (1 ML) on both SnO2 and TiO2(110) surfaces is analysed. To investigate further the intermolecular interactions between adjacent adsorbates, monolayer adsorption on each surface is explored in terms of binding energies and bond lengths. Analysis of the water adsorption geometry and energetics shows that the relative stability of water adsorption on SnO2(110) is governed largely by the strength of the chemisorption and hydrogen bonds at the surface of the adsorbate-substrate system. However on TiO2(110), a more complicated scenario of the first layer of water on its surface arises in which there is an interplay between chemisorption, hydrogen bonding and adsorbate-induced atomic displacements in the surface. Furthermore the projected density of states of each surface in contact with a mixture of adsorbed water molecules and adsorbed hydroxyls is presented and sheds some light on the nature of the crystalline chemical bonds as well as on why adsorbed water has often been reported to be unstable on rutile SnO2(110).

Compounding effects of fluid confinement and surface strain on the wet–dry transition, thermodynamic response, and dynamics of water–graphene systems

DOE PAGES

Chialvo, Ariel A.; Vlcek, Lukas; Cummings, Peter T.

2014-10-17

We studied the link between the water-mediated (tensile or compressive) strain-driven hydration free energy changes in the association process involving finite-size graphene surfaces, the resulting water-graphene interfacial behavior, and the combined effect of surface strain and fluid confinement on the thermodynamic response functions and the dynamics of water. In this study, we found that either small surface corrugation (compressive strain) or surface stretching (tensile strain) is able to enhance significantly the water-graphene hydrophobicity relative to that of the unstrained surface, an effect that exacerbates the confinement impact on the isothermal compressibility and isobaric thermal expansivity of confined water, as wellmore » as on the slowing down of its dynamics that gives rise to anomalous diffusivity.« less

Method and apparatus for production of subsea hydrocarbon formations

DOEpatents

Blandford, J.W.

1995-01-17

A system for controlling, separating, processing and exporting well fluids produced from subsea hydrocarbon formations is disclosed. The subsea well tender system includes a surface buoy supporting one or more decks above the water surface for accommodating equipment to process oil, gas and water recovered from the subsea hydrocarbon formation. The surface buoy includes a surface-piercing central flotation column connected to one or more external flotation tanks located below the water surface. The surface buoy is secured to the sea bed by one or more tendons which are anchored to a foundation with piles imbedded in the sea bed. The system accommodates multiple versions on the surface buoy configuration. 20 figures.

Surface tension isotherms of the dioxane-acetone-water and glycerol-ethanol-water ternary systems

NASA Astrophysics Data System (ADS)

Dzhambulatov, R. S.; Dadashev, R. Kh.; Elimkhanov, D. Z.; Dadashev, I. N.

2016-10-01

The results of the experimental and theoretical studies of the concentration dependence of surface tension of aqueous solutions of the 1,4-dioxane-acetone-water and glycerol-ethanol-water ternary systems were given. The studies were performed by the hanging-drop method on a DSA100 tensiometer. The maximum error of surface tension was 1%. The theoretical models for calculating the surface tension of the ternary systems of organic solutions were analyzed.

Tracking fine-scale seasonal evolution of surface water extent in Central Alaska and the Canadian Shield

NASA Astrophysics Data System (ADS)

Cooley, S. W.; Smith, L. C.; Pitcher, L. H.; Pavelsky, T.; Topp, S.

2017-12-01

Quantifying spatial and temporal variability in surface water storage at high latitudes is critical for assessing environmental sensitivity to climate change. Traditionally the tradeoff between high spatial and high temporal resolution space-borne optical imagery has limited the ability to track fine-scale changes in surface water extent. However, the recent launch of hundreds of earth-imaging CubeSats by commercial satellite companies such as Planet opens up new possibilities for monitoring surface water from space. In this study we present a comparison of seasonal evolution of surface water extent in two study areas with differing geologic, hydrologic and permafrost regimes, namely, the Yukon Flats in Central Alaska and the Canadian Shield north of Yellowknife, N.W.T. Using near-daily 3m Planet CubeSat imagery, we track individual lake surface area from break-up to freeze-up during summer 2017 and quantify the spatial and temporal variability in inundation extent. We validate our water delineation method and inundation extent time series using WorldView imagery, coincident in situ lake shoreline mapping and pressure transducer data for 19 lakes in the Northwest Territories and Alaska collected during the NASA Arctic Boreal Vulnerability Experiment (ABoVE) 2017 field campaign. The results of this analysis demonstrate the value of CubeSat imagery for dynamic surface water research particularly at high latitudes and illuminate fine-scale drivers of cold regions surface water extent.

Aqueous or solvent based surface modification: The influence of the combination solvent - organic functional group on the surface characteristics of titanium dioxide grafted with organophosphonic acids

NASA Astrophysics Data System (ADS)

Roevens, Annelore; Van Dijck, Jeroen G.; Geldof, Davy; Blockhuys, Frank; Prelot, Benedicte; Zajac, Jerzy; Meynen, Vera

2017-09-01

To alter the versatility of interactions at its surface, TiO2 is modified with organophosphonic acids (PA). A thorough understanding of the role of all synthesis conditions is necessary to achieve controlled functionalization. This study reports on the effect of using water, toluene and their mixtures when performing the modification of TiO2 with PA. Sorption and calorimetry measurements of surface interactions with various probing species clearly indicate that, by grafting PA in water, clear differences appear in the distribution of organic groups on the surface. Also the functional group of the PA determines the impact of using water as solvent. Modification in toluene results in a higher modification degree for propylphosphonic acid (3PA), as the solvent-solute interaction may hinder the grafting with phenylphosphonic acid (PhPA) in toluene. Water is preferred as solvent for PhPA modification as stabilizing π-OH interactions enhance surface grafting overcoming the competitive interaction of water at the surface as observed with 3PA. By using water in toluene mixtures for the functionalization of TiO2 with 3PA, the degree of functionalization is higher than when only water or toluene is used. Furthermore, adding small amounts of water leads to the formation of titanium propylphosphonates, next to surface grafting.

DNA damage and oxidative stress in human liver cell L-02 caused by surface water extracts during drinking water treatment in a waterworks in China.

PubMed

Xie, Shao-Hua; Liu, Ai-Lin; Chen, Yan-Yan; Zhang, Li; Zhang, Hui-Juan; Jin, Bang-Xiong; Lu, Wen-Hong; Li, Xiao-Yan; Lu, Wen-Qing

2010-04-01

Because of the daily and life-long exposure to disinfection by-products formed during drinking water treatment, potential adverse human health risk of drinking water disinfection is of great concern. Toxicological studies have shown that drinking water treatment increases the genotoxicity of surface water. Drinking water treatment is comprised of different potabilization steps, which greatly influence the levels of genotoxic products in the surface water and thus may alter the toxicity and genotoxicity of surface water. The aim of the present study was to understand the influence of specific steps on toxicity and genotoxicity during the treatment of surface water in a water treatment plant using liquid chlorine as the disinfectant in China. An integrated approach of the comet and oxidative stress assays was used in the study, and the results showed that both the prechlorination and postchlorination steps increased DNA damage and oxidative stress caused by water extracts in human derived L-02 cells while the tube settling and filtration steps had the opposite effect. This research also highlighted the usefulness of an integrated approach of the comet and oxidative stress assays in evaluating the genotoxicity of surface water during drinking water treatment. Copyright 2009 Wiley-Liss, Inc.

Interpreting contact angle results under air, water and oil for the same surfaces

NASA Astrophysics Data System (ADS)

Ozkan, Orkun; Yildirim Erbil, H.

2017-06-01

Under-water and under-oil superhydropobicity and superhydrophilicity have gained significant attention over the last few years. In this study, contact angles on five flat surfaces (polypropylene, poly(methyl methacrylate), polycarbonate, TEFLON-FEP and glass slide) were measured in water drop-in-air, air bubble-under-water, oil drop-in-air, air bubble-under-oil, oil drop-under-water and water drop-under-oil conditions. Heptane, octane, nonane, decane, dodecane, and hexadecane hydrocarbons were used as oils. Immiscible water/oil pairs were previously mutually saturated to provide thermodynamical equilibrium conditions and their surface and interfacial tensions were determined experimentally. These pairs were used in the two-liquid contact angle measurements. Surface free energies of the solid surfaces in air were determined independently by using the van Oss-Good method, using the contact angle results of pure water, ethylene glycol, formamide, methylene iodide and α-bromonaphalene. In addition, Zisman’s ‘critical surface tension’ values were also determined for comparison. In theory, the summation of contact angle results in a complementary case would give a total of 180° for ideal surfaces. However, it was determined that there are large deviations from this rule in practical cases and these deviations depend on surface free energies of solids. Three complementary cases of (water-in-air with air bubble-under-water); (oil-in-air with air bubble-under-oil); and (oil-under-water with water-under-oil) were investigated in particular to determine the deviations from ideality. A novel approach, named ‘complementary hysteresis’ [γ WA(cosθ 1  -  cosθ 2) and γ OW(cosθ 6  -  cosθ 5)] was developed where γ WA and γ OW represent the interfacial tensions of water/air and oil/water, and θ 1, θ 2, θ 5, and θ 6 were the contact angles of water/air, air bubble/water, oil/water and water/oil respectively. It was experimentally determined that complementary hysteresis varies almost linearly with the surface free energy of the flat solid samples. This is the first report showing the relation of the surface free energy of a solid which is determined under-air with the contact angles obtained on the same solid in different three-phase systems.

Global modeling of withdrawal, allocation and consumptive use of surface water and groundwater resources

NASA Astrophysics Data System (ADS)

Wada, Y.; Wisser, D.; Bierkens, M. F. P.

2013-02-01

To sustain growing food demand and increasing standard of living, global water withdrawal and consumptive water use have been increasing rapidly. To analyze the human perturbation on water resources consistently over a large scale, a number of macro-scale hydrological models (MHMs) have been developed over the recent decades. However, few models consider the feedback between water availability and water demand, and even fewer models explicitly incorporate water allocation from surface water and groundwater resources. Here, we integrate a global water demand model into a global water balance model, and simulate water withdrawal and consumptive water use over the period 1979-2010, considering water allocation from surface water and groundwater resources and explicitly taking into account feedbacks between supply and demand, using two re-analysis products: ERA-Interim and MERRA. We implement an irrigation water scheme, which works dynamically with daily surface and soil water balance, and include a newly available extensive reservoir data set. Simulated surface water and groundwater withdrawal show generally good agreement with available reported national and sub-national statistics. The results show a consistent increase in both surface water and groundwater use worldwide, but groundwater use has been increasing more rapidly than surface water use since the 1990s. Human impacts on terrestrial water storage (TWS) signals are evident, altering the seasonal and inter-annual variability. The alteration is particularly large over the heavily regulated basins such as the Colorado and the Columbia, and over the major irrigated basins such as the Mississippi, the Indus, and the Ganges. Including human water use generally improves the correlation of simulated TWS anomalies with those of the GRACE observations.

CONNECTICUT SURFACE WATER QUALITY CLASSIFICATIONS

EPA Science Inventory

This is a 1:24,000-scale datalayer of Surface Water Quality Classifications for Connecticut. It is comprised of two 0Shapefiles with line and polygon features. Both Shapefiles must be used together with the Hydrography datalayer. The polygon Shapefile includes surface water qual...

Sampling procedure for lake or stream surface water chemistry

Treesearch

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.

Ripple Communication.

ERIC Educational Resources Information Center

Wilcox, R. Stimson

1980-01-01

Discusses how surface-dwelling animals use the water surface as a mode of communication by making ripple signals while they swim about. Provides information about surfaces and surface waves, ripple communication in water striders, ripple signal characteristics, sensing and orienting, other modes of communication, and evolution of ripple…

Water levels and groundwater and surface-water exchanges in lakes of the northeast Twin Cities Metropolitan Area, Minnesota, 2002 through 2015

USGS Publications Warehouse

Jones, Perry M.; Trost, Jared J.; Erickson, Melinda L.

2016-10-19

OverviewThis study assessed lake-water levels and regional and local groundwater and surface-water exchanges near northeast Twin Cities Metropolitan Area lakes applying three approaches: statistical analysis, field study, and groundwater-flow modeling.  Statistical analyses of lake levels were completed to assess the effect of physical setting and climate on lake-level fluctuations of selected lakes. A field study of groundwater and surface-water interactions in selected lakes was completed to (1) estimate potential percentages of surface-water contributions to well water across the northeast Twin Cities Metropolitan Area, (2) estimate general ages for waters extracted from the wells, and (3) assess groundwater inflow to lakes and lake-water outflow to aquifers downgradient from White Bear Lake.  Groundwater flow was simulated using a steady-state, groundwater-flow model to assess regional groundwater and surface-water exchanges and the effects of groundwater withdrawals, climate, and other factors on water levels of northeast Twin Cities Metropolitan Area lakes.

Terrestrial water storage variations and surface vertical deformation derived from GPS and GRACE observations in Nepal and Himalayas

NASA Astrophysics Data System (ADS)

Pan, Y.; Shen, W.; Hwang, C.

2015-12-01

As an elastic Earth, the surface vertical deformation is in response to hydrological mass change on or near Earth's surface. The continuous GPS (CGPS) records show surface vertical deformations which are significant information to estimate the variation of terrestrial water storage. We compute the loading deformations at GPS stations based on synthetic models of seasonal water load distribution and then invert the synthetic GPS data for surface mass distribution. We use GRACE gravity observations and hydrology models to evaluate seasonal water storage variability in Nepal and Himalayas. The coherence among GPS inversion results, GRACE and hydrology models indicate that GPS can provide quantitative estimates of terrestrial water storage variations by inverting the surface deformation observations. The annual peak-to-peak surface mass change derived from GPS and GRACE results reveal seasonal loads oscillations of water, snow and ice. Meanwhile, the present uplifting of Nepal and Himalayas indicates the hydrology mass loss. This study is supported by National 973 Project China (grant Nos. 2013CB733302 and 2013CB733305), NSFC (grant Nos. 41174011, 41429401, 41210006, 41128003, 41021061).

Field and laboratory determination of water-surface elevation and velocity using noncontact measurements

USGS Publications Warehouse

Nelson, Jonathan M.; Kinzel, Paul J.; Schmeeckle, Mark Walter; McDonald, Richard R.; Minear, Justin T.

2016-01-01

Noncontact methods for measuring water-surface elevation and velocity in laboratory flumes and rivers are presented with examples. Water-surface elevations are measured using an array of acoustic transducers in the laboratory and using laser scanning in field situations. Water-surface velocities are based on using particle image velocimetry or other machine vision techniques on infrared video of the water surface. Using spatial and temporal averaging, results from these methods provide information that can be used to develop estimates of discharge for flows over known bathymetry. Making such estimates requires relating water-surface velocities to vertically averaged velocities; the methods here use standard relations. To examine where these relations break down, laboratory data for flows over simple bumps of three amplitudes are evaluated. As anticipated, discharges determined from surface information can have large errors where nonhydrostatic effects are large. In addition to investigating and characterizing this potential error in estimating discharge, a simple method for correction of the issue is presented. With a simple correction based on bed gradient along the flow direction, remotely sensed estimates of discharge appear to be viable.

Wettability, Polarity, and Water Absorption of Holm Oak Leaves: Effect of Leaf Side and Age1[OPEN

PubMed Central

Fernández, Victoria; Sancho-Knapik, Domingo; Guzmán, Paula; Peguero-Pina, José Javier; Gil, Luis; Karabourniotis, George; Khayet, Mohamed; Fasseas, Costas; Heredia-Guerrero, José Alejandro; Heredia, Antonio; Gil-Pelegrín, Eustaquio

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 holm oak (Quercus ilex) as a model. By measuring the leaf water potential 24 h after the deposition of water drops onto abaxial and adaxial surfaces, evidence for water penetration through the upper leaf side was gained in young and mature leaves. The structure and chemical composition of the abaxial (always present) and adaxial (occurring only in young leaves) trichomes were analyzed by various microscopic and analytical procedures. The adaxial surfaces were wettable and had a high degree of water drop adhesion in contrast to the highly unwettable and water-repellent abaxial holm oak leaf sides. The surface free energy and solubility parameter decreased with leaf age, with higher values determined for the adaxial sides. All holm oak leaf trichomes were covered with a cuticle. The abaxial trichomes were composed of 8% soluble waxes, 49% cutin, and 43% polysaccharides. For the adaxial side, it is concluded that trichomes and the scars after trichome shedding contribute to water uptake, while the abaxial leaf side is highly hydrophobic due to its high degree of pubescence and different trichome structure, composition, and density. Results are interpreted in terms of water-plant surface interactions, plant surface physical chemistry, and plant ecophysiology. PMID:24913938

Trawling bats exploit an echo-acoustic ground effect

PubMed Central

Zsebok, Sandor; Kroll, Ferdinand; Heinrich, Melina; Genzel, Daria; Siemers, Björn M.; Wiegrebe, Lutz

2013-01-01

A water surface acts not only as an optic mirror but also as an acoustic mirror. Echolocation calls emitted by bats at low heights above water are reflected away from the bat, and hence the background clutter is reduced. Moreover, targets on the surface create an enhanced echo. Here, we formally quantified the effect of the surface and target height on both target detection and -discrimination in a combined laboratory and field approach with Myotis daubentonii. In a two-alternative, forced-choice paradigm, the bats had to detect a mealworm and discriminate it from an inedible dummy (20 mm PVC disc). Psychophysical performance was measured as a function of height above either smooth surfaces (water or PVC) or above a clutter surface (artificial grass). At low heights above the clutter surface (10, 20, or 35 cm), the bats' detection performance was worse than above a smooth surface. At a height of 50 cm, the surface structure had no influence on target detection. Above the clutter surface, also target discrimination was significantly impaired with decreasing target height. A detailed analysis of the bats' echolocation calls during target approach shows that above the clutter surface, the bats produce calls with significantly higher peak frequency. Flight-path reconstruction revealed that the bats attacked an target from below over water but from above over a clutter surface. These results are consistent with the hypothesis that trawling bats exploit an echo-acoustic ground effect, in terms of a spatio-temporal integration of direct reflections with indirect reflections from the water surface, to optimize prey detection and -discrimination not only for prey on the water but also for some range above. PMID:23576990

Fabrication of superhydrophobic copper surface on various substrates for roll-off, self-cleaning, and water/oil separation.

PubMed

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.

CH4 Hydrate Formation between Silica and Graphite Surfaces: Insights from Microsecond Molecular Dynamics Simulations.

PubMed

He, Zhongjin; Linga, Praveen; Jiang, Jianwen

2017-10-31

Microsecond simulations have been performed to investigate CH 4 hydrate formation from gas/water two-phase systems between silica and graphite surfaces, respectively. The hydrophilic silica and hydrophobic graphite surfaces exhibit substantially different effects on CH 4 hydrate formation. The graphite surface adsorbs CH 4 molecules to form a nanobubble with a flat or negative curvature, resulting in a low aqueous CH 4 concentration, and hydrate nucleation does not occur during 2.5 μs simulation. Moreover, an ordered interfacial water bilayer forms between the nanobubble and graphite surface thus preventing their direct contact. In contrast, the hydroxylated-silica surface prefers to be hydrated by water, with a cylindrical nanobubble formed in the solution, leading to a high aqueous CH 4 concentration and hydrate nucleation in the bulk region; during hydrate growth, the nanobubble is gradually covered by hydrate solid and separated from the water phase, hence slowing growth. The silanol groups on the silica surface can form strong hydrogen bonds with water, and hydrate cages need to match the arrangements of silanols to form more hydrogen bonds. At the end of the simulation, the hydrate solid is separated from the silica surface by liquid water, with only several cages forming hydrogen bonds with the silica surface, mainly due to the low CH 4 aqueous concentrations near the surface. To further explore hydrate formation between graphite surfaces, CH 4 /water homogeneous solution systems are also simulated. CH 4 molecules in the solution are adsorbed onto graphite and hydrate nucleation occurs in the bulk region. During hydrate growth, the adsorbed CH 4 molecules are gradually converted into hydrate solid. It is found that the hydrate-like ordering of interfacial water induced by graphite promotes the contact between hydrate solid and graphite. We reveal that the ability of silanol groups on silica to form strong hydrogen bonds to stabilize incipient hydrate solid, as well as the ability of graphite to adsorb CH 4 molecules and induce hydrate-like ordering of the interfacial water, are the key factors to affect CH 4 hydrate formation between silica and graphite surfaces.

Water-quality conditions and an evaluation of ground- and surface-water sampling programs in the Livermore-Amador Valley, California

USGS Publications Warehouse

Sorenson, S.K.; Cascos, P.V.; Glass, R.L.

1984-01-01

A program to monitor the ground- and surface water quality in the Livermore-Amador Valley has been operated since 1976. As of 1982, this monitoring network consisted of approximately 130 wells, about 100 of which were constructed specifically for this program, and 9 surface water stations. Increased demand on the groundwater for municipal and industrial water supply in the past has caused a decline in water levels and a gradual buildup of salts from natural surface-water recharge and land disposal of treated wastewater from waste treatment plants. Results of this study identify the salt buildup to be the major problem with the groundwater quality. Established water quality objectives for dissolved solids are exceeded in 52 of 130 wells. Concentrations of dissolved nitrate are also in excess of basin objectives and health standards. Water quality in both surface and groundwater is highly variable areally. Magnesium to calcium magnesium bicarbonate groundwater are found in the areas where most of the high volume municipal wells are located. Large areas of sodium bicarbonate water occur in the northern part of the valley. Except for two stations on Arroyo Las Positas which has sodium chloride water, surface water is mixed-cation bicarbonate water. (USGS)

Chlorine stress mediates microbial surface attachment in drinking water systems.

PubMed

Liu, Li; Le, Yang; Jin, Juliang; Zhou, Yuliang; Chen, Guowei

2015-03-01

Microbial attachment to drinking water pipe surfaces facilitates pathogen survival and deteriorates disinfection performance, directly threatening the safety of drinking water. Notwithstanding that the formation of biofilm has been studied for decades, the underlying mechanisms for the origins of microbial surface attachment in biofilm development in drinking water pipelines remain largely elusive. We combined experimental and mathematical methods to investigate the role of environmental stress-mediated cell motility on microbial surface attachment in chlorination-stressed drinking water distribution systems. Results show that at low levels of disinfectant (0.0-1.0 mg/L), the presence of chlorine promotes initiation of microbial surface attachment, while higher amounts of disinfectant (>1.0 mg/L) inhibit microbial attachment. The proposed mathematical model further demonstrates that chlorination stress (0.0-5.0 mg/L)-mediated microbial cell motility regulates the frequency of cell-wall collision and thereby controls initial microbial surface attachment. The results reveal that transport processes and decay patterns of chlorine in drinking water pipelines regulate microbial cell motility and, thus, control initial surface cell attachment. It provides a mechanistic understanding of microbial attachment shaped by environmental disinfection stress and leads to new insights into microbial safety protocols in water distribution systems.

Permian paleoclimate data from fluid inclusions in halite

USGS Publications Warehouse

Benison, K.C.; Goldstein, R.H.

1999-01-01

This study has yielded surface water paleotemperatures from primary fluid inclusions in mid Permian Nippewalla Group halite from western Kansas. A 'cooling nucleation' method is used to generate vapor bubbles in originally all-liquid primary inclusions. Then, surface water paleotemperatures are obtained by measuring temperatures of homogenization to liquid. Homogenization temperatures ranged from 21??C to 50??C and are consistent along individual fluid inclusion assemblages, indicating that the fluid inclusions have not been altered by thermal reequilibration. Homogenization temperatures show a range of up to 26??C from base to top of individual cloudy chevron growth bands. Petrographic and fluid inclusion evidence indicate that no significant pressure correction is needed for the homogenization temperature data. We interpret these homogenization temperatures to represent shallow surface water paleotemperatures. The range in temperatures from base to top of single chevron bands may reflect daily temperatures variations. These Permian surface water temperatures fall within the same range as some modern evaporative surface waters, suggesting that this Permian environment may have been relatively similar to its modern counterparts. Shallow surface water temperatures in evaporative settings correspond closely to local air temperatures. Therefore, the Permian surface water temperatures determined in this study may be considered proxies for local Permian air temperatures.

Noncontact methods for measuring water-surface elevations and velocities in rivers: Implications for depth and discharge extraction

USGS Publications Warehouse

Nelson, Jonathan M.; Kinzel, Paul J.; McDonald, Richard R.; Schmeeckle, Mark

2016-01-01

Recently developed optical and videographic methods for measuring water-surface properties in a noninvasive manner hold great promise for extracting river hydraulic and bathymetric information. This paper describes such a technique, concentrating on the method of infrared videog- raphy for measuring surface velocities and both acoustic (laboratory-based) and laser-scanning (field-based) techniques for measuring water-surface elevations. In ideal laboratory situations with simple flows, appropriate spatial and temporal averaging results in accurate water-surface elevations and water-surface velocities. In test cases, this accuracy is sufficient to allow direct inversion of the governing equations of motion to produce estimates of depth and discharge. Unlike other optical techniques for determining local depth that rely on transmissivity of the water column (bathymetric lidar, multi/hyperspectral correlation), this method uses only water-surface information, so even deep and/or turbid flows can be investigated. However, significant errors arise in areas of nonhydrostatic spatial accelerations, such as those associated with flow over bedforms or other relatively steep obstacles. Using laboratory measurements for test cases, the cause of these errors is examined and both a simple semi-empirical method and computational results are presented that can potentially reduce bathymetric inversion errors.

Predictability and Quantification of Complex Groundwater Table Dynamics Driven by Irregular Surface Water Fluctuations

NASA Astrophysics Data System (ADS)

Xin, Pei; Wang, Shen S. J.; Shen, Chengji; Zhang, Zeyu; Lu, Chunhui; Li, Ling

2018-03-01

Shallow groundwater interacts strongly with surface water across a quarter of global land area, affecting significantly the terrestrial eco-hydrology and biogeochemistry. We examined groundwater behavior subjected to unimodal impulse and irregular surface water fluctuations, combining physical experiments, numerical simulations, and functional data analysis. Both the experiments and numerical simulations demonstrated a damped and delayed response of groundwater table to surface water fluctuations. To quantify this hysteretic shallow groundwater behavior, we developed a regression model with the Gamma distribution functions adopted to account for the dependence of groundwater behavior on antecedent surface water conditions. The regression model fits and predicts well the groundwater table oscillations resulting from propagation of irregular surface water fluctuations in both laboratory and large-scale aquifers. The coefficients of the Gamma distribution function vary spatially, reflecting the hysteresis effect associated with increased amplitude damping and delay as the fluctuation propagates. The regression model, in a relatively simple functional form, has demonstrated its capacity of reproducing high-order nonlinear effects that underpin the surface water and groundwater interactions. The finding has important implications for understanding and predicting shallow groundwater behavior and associated biogeochemical processes, and will contribute broadly to studies of groundwater-dependent ecology and biogeochemistry.

Surface-Water Quality-Assurance Plan for the Tallahassee Office, U.S. Geological Survey

USGS Publications Warehouse

Tomlinson, Stewart A.

2006-01-01

This Tallahassee Office Surface-Water Quality-Assurance Plan documents the standards, policies, and procedures used by the Tallahassee Office for activities related to the collection, processing, storage, analysis, and publication of surface-water data. This plan serves as a guide to all Tallahassee Office personnel involved in surface-water data activities, and changes as the needs and requirements of the Tallahassee Office, Florida Integrated Science Center, and Water Discipline change. Reg-ular updates to this Plan represent an integral part of the quality-assurance process. In the Tallahassee Office, direct oversight and responsibility by the employee(s) assigned to a surface-water station, combined with team approaches in all work efforts, assure high-quality data, analyses, reviews, and reports for cooperating agencies and the public.

Occurrence of pesticides and contaminants of emerging concern in surface waters: Influence of surrounding land use and evaluation of sampling methods

USDA-ARS?s Scientific Manuscript database

Biologically active compounds originating from agricultural, residential, and industrial sources have been detected in surface waters, which have invoked concern of their potential ecological and human health effects. Automated and grab surface water samples, passive water samples - Polar Organic Co...

Description of the surface water filtration and ozone treatment system at the Northeast Fishery Center

USDA-ARS?s Scientific Manuscript database

A water filtration and ozone disinfection system was installed at the U.S. Fish and Wildlife Service's Northeast Fishery Center in Lamar, Pennsylvania to treat a surface water supply that is used to culture sensitive and endangered fish. The treatment system first passes the surface water through dr...

Nutrient Loss in Runoff from Turf: Effect on Surface Water Quality

USDA-ARS?s Scientific Manuscript database

Excess nutrients in surface waters may result in enhanced algal blooms and plant growth that can lead to eutrophication and a decline in water quality. The applicatin of fertilizer to golf courses may be a source of nutrients to surface waters. Runoff studies were conducted to measure applied nitrog...

Potential health implications of water resources depletion and sewage discharges in the Republic of Macedonia.

PubMed

Hristovski, Kiril D; Pacemska-Atanasova, Tatjana; Olson, Larry W; Markovski, Jasmina; Mitev, Trajce

2016-08-01

Potential health implications of deficient sanitation infrastructure and reduced surface water flows due to climate change are examined in the case study of the Republic of Macedonia. Changes in surface water flows and wastewater discharges over the period 1955-2013 were analyzed to assess potential future surface water contamination trends. Simple model predictions indicated a decline in surface water hydrology over the last half century, which caused the surface waters in Macedonia to be frequently dominated by >50% of untreated sewage discharges. The surface water quality deterioration is further supported by an increasing trend in modeled biochemical oxygen demand trends, which correspond well with the scarce and intermittent water quality data that are available. Facilitated by the climate change trends, the increasing number of severe weather events is already triggering flooding of the sewage-dominated rivers into urban and non-urban areas. If efforts to develop a comprehensive sewage collection and treatment infrastructure are not implemented, such events have the potential to increase public health risks and cause epidemics, as in the 2015 case of a tularemia outbreak.

Metagenomes of Microbial Communities in Arsenic- and Pathogen-Contaminated Well and Surface Water from Bangladesh

PubMed Central

Layton, Alice C.; Chauhan, Archana; Williams, Daniel E.; Mailloux, Brian; Knappett, Peter S. K.; Ferguson, Andrew S.; McKay, Larry D.; Alam, M. Jahangir; Matin Ahmed, Kazi; van Geen, Alexander

2014-01-01

The contamination of drinking water from both arsenic and microbial pathogens occurs in Bangladesh. A general metagenomic survey of well water and surface water provided information on the types of pathogens present and may help elucidate arsenic metabolic pathways and potential assay targets for monitoring surface-to-ground water pathogen transport. PMID:25414497

Desert Beetle-Inspired Superwettable Patterned Surfaces for Water Harvesting.

PubMed

Yu, Zhenwei; Yun, Frank F; Wang, Yanqin; Yao, Li; Dou, Shixue; Liu, Kesong; Jiang, Lei; Wang, Xiaolin

2017-09-01

With the impacts of climate change and impending crisis of clean drinking water, designing functional materials for water harvesting from fog with large water capacity has received much attention in recent years. Nature has evolved different strategies for surviving dry, arid, and xeric conditions. Nature is a school for human beings. In this contribution, inspired by the Stenocara beetle, superhydrophilic/superhydrophobic patterned surfaces are fabricated on the silica poly(dimethylsiloxane) (PDMS)-coated superhydrophobic surfaces using a pulsed laser deposition approach with masks. The resultant samples with patterned wettability demonstrate water-harvesting efficiency in comparison with the silica PDMS-coated superhydrophobic surface and the Pt nanoparticles-coated superhydrophilic surface. The maximum water-harvesting efficiency can reach about 5.3 g cm -2 h -1 . Both the size and the percentage of the Pt-coated superhydrophilic square regions on the patterned surface affect the condensation and coalescence of the water droplet, as well as the final water-harvesting efficiency. The present water-harvesting strategy should provide an avenue to alleviate the water crisis facing mankind in certain arid regions of the world. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nanoscale water condensation on click-functionalized self-assembled monolayers.

PubMed

James, Michael; Ciampi, Simone; Darwish, Tamim A; Hanley, Tracey L; Sylvester, Sven O; Gooding, J Justin

2011-09-06

We have examined the nanoscale adsorption of molecular water under ambient conditions onto a series of well-characterized functionalized surfaces produced by Cu(I)-catalyzed alkyne-azide cycloaddition (CuAAC or "click") reactions on alkyne-terminated self-assembled monolayers on silicon. Water contact angle (CA) measurements reveal a range of macroscopic hydrophilicity that does not correlate with the tendency of these surfaces to adsorb water at the molecular level. X-ray reflectometry has been used to follow the kinetics of water adsorption on these "click"-functionalized surfaces, and also shows that dense continuous molecular water layers are formed over 30 h. For example, a highly hydrophilic surface, functionalized by an oligo(ethylene glycol) moiety (with a CA = 34°) showed 2.9 Å of adsorbed water after 30 h, while the almost hydrophobic underlying alkyne-terminated monolayer (CA = 84°) showed 5.6 Å of adsorbed water over the same period. While this study highlights the capacity of X-ray reflectometry to study the structure of adsorbed water on these surfaces, it should also serve as a warning for those intending to characterize self-assembled monolayers and functionalized surfaces to avoid contamination by even trace amounts of water vapor. Moreover, contact angle measurements alone cannot be relied upon to predict the likely degree of moisture uptake on such surfaces. © 2011 American Chemical Society

40 CFR 258.27 - Surface water requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 25 2011-07-01 2011-07-01 false Surface water requirements. 258.27 Section 258.27 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES CRITERIA FOR MUNICIPAL SOLID WASTE LANDFILLS Operating Criteria § 258.27 Surface water requirements. MSWLF...

Surface fractal dimension, water adsorption efficiency, and cloud nucleation activity of insoluble aerosol.

PubMed

Laaksonen, Ari; Malila, Jussi; Nenes, Athanasios; Hung, Hui-Ming; Chen, Jen-Ping

2016-05-03

Surface porosity affects the ability of a substance to adsorb gases. The surface fractal dimension D is a measure that indicates the amount that a surface fills a space, and can thereby be used to characterize the surface porosity. Here we propose a new method for determining D, based on measuring both the water vapour adsorption isotherm of a given substance, and its ability to act as a cloud condensation nucleus when introduced to humidified air in aerosol form. We show that our method agrees well with previous methods based on measurement of nitrogen adsorption. Besides proving the usefulness of the new method for general surface characterization of materials, our results show that the surface fractal dimension is an important determinant in cloud drop formation on water insoluble particles. We suggest that a closure can be obtained between experimental critical supersaturation for cloud drop activation and that calculated based on water adsorption data, if the latter is corrected using the surface fractal dimension of the insoluble cloud nucleus.

Surface fractal dimension, water adsorption efficiency, and cloud nucleation activity of insoluble aerosol

NASA Astrophysics Data System (ADS)

Laaksonen, Ari; Malila, Jussi; Nenes, Athanasios; Hung, Hui-Ming; Chen, Jen-Ping

2016-05-01

Surface porosity affects the ability of a substance to adsorb gases. The surface fractal dimension D is a measure that indicates the amount that a surface fills a space, and can thereby be used to characterize the surface porosity. Here we propose a new method for determining D, based on measuring both the water vapour adsorption isotherm of a given substance, and its ability to act as a cloud condensation nucleus when introduced to humidified air in aerosol form. We show that our method agrees well with previous methods based on measurement of nitrogen adsorption. Besides proving the usefulness of the new method for general surface characterization of materials, our results show that the surface fractal dimension is an important determinant in cloud drop formation on water insoluble particles. We suggest that a closure can be obtained between experimental critical supersaturation for cloud drop activation and that calculated based on water adsorption data, if the latter is corrected using the surface fractal dimension of the insoluble cloud nucleus.

Assessment of volatile organic compounds in surface water at West Branch Canal Creek, Aberdeen Proving Ground, Maryland, 1999

USGS Publications Warehouse

Olsen, Lisa D.; Spencer, Tracey A.

2000-01-01

The U.S. Geological Survey (USGS) collected 13 surface-water samples and 3 replicates from 5 sites in the West Branch Canal Creek area at Aberdeen Proving Ground from February through August 1999, as a part of an investigation of ground-water contamination and natural attenuation processes. The samples were analyzed for volatile organic compounds, including trichloroethylene, 1,1,2,2-tetrachloroethane, carbon tetrachloride, and chloroform, which are the four major contaminants that were detected in ground water in the Canal Creek area in earlier USGS studies. Field blanks were collected during the sampling period to assess sample bias. Field replicates were used to assess sample variability, which was expressed as relative percent difference. The mean variability of the surface-water replicate analyses was larger (35.4 percent) than the mean variability of ground-water replicate analyses (14.6 percent) determined for West Branch Canal Creek from 1995 through 1996. The higher variability in surface-water analyses is probably due to heterogeneities in the composition of the surface water rather than differences in sampling or analytical procedures. The most frequently detected volatile organic compound was 1,1,2,2- tetrachloroethane, which was detected in every sample and in two of the replicates. The surface-water contamination is likely the result of cross-media transfer of contaminants from the ground water and sediments along the West Branch Canal Creek. The full extent of surface-water contamination in West Branch Canal Creek and the locations of probable contaminant sources cannot be determined from this limited set of data. Tidal mixing, creek flow patterns, and potential effects of a drought that occurred during the sampling period also complicate the evaluation of surface-water contamination.

Identifying the regional-scale groundwater-surface water interaction on the Sanjiang Plain, Northeast China.

PubMed

Wang, Xihua; Zhang, Guangxin; Xu, Y Jun; Sun, Guangzhi

2015-11-01

Assessment on the interaction between groundwater and surface water (GW-SW) can generate information that is critical to regional water resource management, especially for regions that are highly dependent on groundwater resources for irrigation. This study investigated such interaction on China's Sanjiang Plain (10.9 × 10(4) km(2)) and produced results to assist sustainable regional water management for intensive agricultural activities. Methods of hierarchical cluster analysis (HCA), principal component analysis (PCA), and statistical analysis were used in this study. One hundred two water samplings (60 from shallow groundwater, 7 from deep groundwater, and 35 from surface water) were collected and grouped into three clusters and seven sub-clusters during the analyses. The PCA analysis identified four principal components of the interaction, which explained 85.9% variance of total database, attributed to the dissolution and evolution of gypsum, feldspar, and other natural minerals in the region that was affected by anthropic and geological (sedimentary rock mineral) activities. The analyses showed that surface water in the upper region of the Sanjiang Plain gained water from local shallow groundwater, indicating that the surface water in the upper region was relatively more resilient to withdrawal for usage, whereas in the middle region, there was only a weak interaction between shallow groundwater and surface water. In the lower region of the Sanjiang Plain, surface water lost water to shallow groundwater, indicating that the groundwater was vulnerable to pollution by pesticides and fertilizers from terrestrial sources.

Results of soil, ground-water, surface-water, and streambed-sediment sampling at Air Force Plane 85, Columbus, Ohio, 1996

USGS Publications Warehouse

Parnell, J.M.

1997-01-01

The U.S. Geological Survey (USGS), in cooperation with Aeronautical Systems Center, Environmental Management Directorate, Restoration Division, prepared the Surface- and Ground- Water Monitoring Work Plan for Air Force Plant 85 (AFP 85 or Plant), Columbus, Ohio, under the Air Force Installation Restoration Program to characterize any ground-water, surface-water, and soil contamination that may exist at AFP 85. The USGS began the study in November 1996. The Plant was divided into nine sampling areas, which included some previously investi gated study sites. The investigation activities included the collection and presentation of data taken during drilling and water-quality sampling. Data collection focused on the saturated and unsatur ated zones and surface water. Twenty-three soil borings were completed. Ten monitoring wells (six existing wells and four newly constructed monitoring wells) were selected for water-quality sam pling. Surface-water and streambed-sediment sampling locations were chosen to monitor flow onto and off of the Plant. Seven sites were sampled for both surface-water and streambed-sediment quality. This report presents data on the selected inorganic and organic constituents in soil, ground water, surface water, and streambed sediments at AFP 85. The methods of data collection and anal ysis also are included. Knowledge of the geologic and hydrologic setting could aid Aeronautical Systems Center, Environmental Management Directorate, Restoration Division, and its governing regulatory agencies in future remediation studies.

A novel orthogonal transmission-virtual grating method and its applications in measuring micro 3-D shape of deformed liquid surface

NASA Astrophysics Data System (ADS)

Liu, Zhanwei; Huang, Xianfu; Xie, Huimin

2013-02-01

Deformed liquid surface directly involves the surface tension, which can always be used to account for the kinematics of aquatic insects in gas-liquid interface and the light metal floating on the water surface. In this paper a novel method based upon deformed transmission-virtual grating is proposed for determination of deformed liquid surface. By addressing an orthogonal grating (1-5 line/mm) under the transparent water groove and then capturing images from upset of the deformed water surface, a displacement vector of full-field which directly associates the 3-D deformed liquid surface then can be evaluated by processing the recorded deformed fringe pattern in the two directions (x- and y-direction). Theories and equations for the method are thoroughly delivered. Validation test to measure the deformed water surface caused by a Chinese 1-cent coin has been conducted to demonstrate the ability of the developed method. The obtained results show that the method is robust in determination of micro 3-D surface of deformed liquid with a submicron scale resolution and with a wide range application scope.

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

USGS Publications Warehouse

Garn, H.S.

2007-01-01

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

Inventory of File sref_nmb.t03z.pgrb221.p1.f06.grib2

Science.gov Websites

surface WEASD 6 hour fcst Water Equivalent of Accumulated Snow Depth [kg/m^2] 016 surface APCP 3-6 hour surface WEASD 3-6 hour acc Water Equivalent of Accumulated Snow Depth [kg/m^2] 019 surface CSNOW 6 hour surface NCPCP 3-6 hour acc Large-Scale Precipitation (non-convective) [kg/m^2] 404 surface SNOM 3-6 hour

Inventory of File sref_nmm.t03z.pgrb221.p1.f06.grib2

Science.gov Websites

surface WEASD 6 hour fcst Water Equivalent of Accumulated Snow Depth [kg/m^2] 016 surface APCP 3-6 hour surface WEASD 3-6 hour acc Water Equivalent of Accumulated Snow Depth [kg/m^2] 019 surface CSNOW 6 hour surface NCPCP 3-6 hour acc Large-Scale Precipitation (non-convective) [kg/m^2] 404 surface SNOM 3-6 hour

The surface stability and morphology of tobermorite 11 Å from first principles

NASA Astrophysics Data System (ADS)

Mutisya, Sylvia M.; Miranda, Caetano R.

2018-06-01

Tobermorite minerals are important in many industrial processes typically occurring in hydrous environment. Their functionality is therefore governed in various aspects by their morphology and surface stability/reactivity. Here, we present the results of the surface energies and morphology of normal tobermorite 11 Å in a water vapor environment investigated by employing first principles atomistic thermodynamic calculations. For the low index tobermorite surfaces studied, the calculated surface energies fall within a narrow range (0.41-0.97 J/m2) with the (0 0 4) surface being the most stable. The equilibrium morphology is a thin pseudohexagonal plate elongated along the b axis. The hydrated surfaces are more stable at high water vapor chemical potentials with the stability enhanced as the water partial pressures are varied from ambient to supercritical hydrothermal conditions. Increasing the water vapor chemical potential gives rise to a smaller size of the tobermorite crystal, with the equilibrium morphology remaining unaltered.

Influence of LaFeO 3 Surface Termination on Water Reactivity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stoerzinger, Kelsey A.; Comes, Ryan; Spurgeon, Steven R.

2017-02-17

The polarity of oxide surfaces can dramatically impact their surface reactivity, in particular with polar molecules such as water. The surface species that result from this interaction change the oxide electronic structure and chemical reactivity in applications such as photoelectrochemistry, but are challenging to probe experimentally with atomic-scale understanding. Here we report a detailed study of the surface chemistry and electronic structure of the perovskite LaFeO3 in humid conditions using ambient pressure X-ray photoelectron spectroscopy. Comparing the two possible terminations of the polar (001)-oriented surface, we find that the LaO surface is more reactive toward water, forming hydroxyl species andmore » adsorbing molecular water at lower relative humidity than its FeO2-terminated counterpart. Our results demonstrate how the termination of a complex oxide can dramatically impact its reactivity, providing insight into the design of catalyst materials.« less

Effect of surface roughness on droplet splashing

NASA Astrophysics Data System (ADS)

Hao, Jiguang

2017-12-01

It is well known that rough surfaces trigger prompt splashing and suppress corona splashing on droplet impact. Upon water droplet impact, we experimentally found that a slightly rough substrate triggers corona splashing which is suppressed to prompt splashing by both further increase and further decrease of surface roughness. The nonmonotonic effect of surface roughness on corona splashing weakens with decreasing droplet surface tension. The threshold velocities for prompt splashing and corona splashing are quantified under different conditions including surface roughness, droplet diameter, and droplet surface tension. It is determined that slight roughness significantly enhances both prompt splashing and corona splashing of a water droplet, whereas it weakly affects low-surface-tension droplet splashing. Consistent with previous studies, high roughness triggers prompt splashing and suppresses corona splashing. Further experiments on droplet spreading propose that the mechanism of slight roughness enhancing water droplet splashing is due to the decrease of the wetted area with increasing surface roughness.

Surface characterization of gallium nitride modified with peptides before and after exposure to ionizing radiation in solution.

PubMed

Berg, Nora G; Nolan, Michael W; Paskova, Tania; Ivanisevic, Albena

2014-12-30

An aqueous surface modification of gallium nitride was employed to attach biomolecules to the surface. The modification was a simple two-step process using a single linker molecule and mild temperatures. The presence of the peptide on the surface was confirmed with X-ray photoelectron spectroscopy. Subsequently, the samples were placed in water baths and exposed to ionizing radiation to examine the effects of the radiation on the material in an environment similar to the body. Surface analysis confirmed degradation of the surface of GaN after radiation exposure in water; however, the peptide molecules successfully remained on the surface following exposure to ionizing radiation. We hypothesize that during radiation exposure of the samples, the radiolysis of water produces peroxide and other reactive species on the sample surface. Peroxide exposure promotes the formation of a more stable layer of gallium oxyhydroxide which passivates the surface better than other oxide species.

Tribological properties of fish scale inspired underwater superoleophobic hierarchical structure in aqueous environment

NASA Astrophysics Data System (ADS)

Lian, Zhongxu; Xu, Jinkai; Wan, Yanling; Li, Yiquan; Yu, Zhanjiang; Liu, Qimeng; Yu, Huadong

2017-10-01

Underwater superoleophobic surfaces are becoming increasingly important in regard to self-cleaning, anti-fouling, oil droplet transportation and water/oil separation. Although a great number of underwater superoleophobic surfaces have been demonstrated, their tribological properties remain impractical for the purposes of real-life applications. Herein, a two-step method of high speed wire electrical discharge machining and boiling water treatment was adopted to fabricate fish scale inspired underwater oil repellent hierarchical structure on an aluminum (Al) alloy 5083 surface. The hierarchical roughness and hydroxyl groups were obtained on the surface, and the surface exhibited the ability to prevent contact with organic fluids when submerged in water. Moreover, the tribological properties of underwater superoleophobic Al surfaces in aqueous environments were analyzed. The average friction coefficient of underwater superoleophobic surfaces was decreased compared with the polished Al surface. We believe that this research will contribute to the engineering application of underwater superoleophobic surfaces in the future.

How Properties of Solid Surfaces Modulate the Nucleation of Gas Hydrate

PubMed Central

Bai, Dongsheng; Chen, Guangjin; Zhang, Xianren; Sum, Amadeu K.; Wang, Wenchuan

2015-01-01

Molecular dynamics simulations were performed for CO2 dissolved in water near silica surfaces to investigate how the hydrophilicity and crystallinity of solid surfaces modulate the local structure of adjacent molecules and the nucleation of CO2 hydrates. Our simulations reveal that the hydrophilicity of solid surfaces can change the local structure of water molecules and gas distribution near liquid-solid interfaces, and thus alter the mechanism and dynamics of gas hydrate nucleation. Interestingly, we find that hydrate nucleation tends to occur more easily on relatively less hydrophilic surfaces. Different from surface hydrophilicity, surface crystallinity shows a weak effect on the local structure of adjacent water molecules and on gas hydrate nucleation. At the initial stage of gas hydrate growth, however, the structuring of molecules induced by crystalline surfaces are more ordered than that induced by amorphous solid surfaces. PMID:26227239

Hydrologic considerations in defining isolated wetlands

USGS Publications Warehouse

Winter, T.C.; LaBaugh, J.W.

2003-01-01

Wetlands that are not connected by streams to other surface-water bodies are considered to be isolated. Although the definition is based on surface-water connections to other water bodies, isolated wetlands commonly are integral parts of extensive ground-water flow systems, and isolated wetlands can spill over their surface divides into adjacent surface-water bodies during periods of abundant precipitation and high water levels. Thus, characteristics of ground-water flow and atmospheric-water flow affect the isolation of wetlands. In general, the degree that isolated wetlands are connected through the ground-water system to other surface-water bodies depends to a large extent on the rate that ground water moves and the rate that hydrologic stresses can be transmitted through the ground-water system. Water that seeps from an isolated wetland into a gravel aquifer can travel many kilometers through the ground-water system in one year. In contrast, water that seeps from an isolated wetland into a clayey or silty substrate may travel less than one meter in one year. For wetlands that can spill over their surface watersheds during periods of wet climate conditions, their isolation is related to the height to a spill elevation above normal wetland water level and the recurrence interval of various magnitudes of precipitation. The concepts presented in this paper indicate that the entire hydrologic system needs to be considered in establishing a definition of hydrologic isolation.

High-resolution mapping of global surface water and its long-term changes

NASA Astrophysics Data System (ADS)

Pekel, Jean-François; Cottam, Andrew; Gorelick, Noel; Belward, Alan S.

2016-12-01

The location and persistence of surface water (inland and coastal) is both affected by climate and human activity and affects climate, biological diversity and human wellbeing. Global data sets documenting surface water location and seasonality have been produced from inventories and national descriptions, statistical extrapolation of regional data and satellite imagery, but measuring long-term changes at high resolution remains a challenge. Here, using three million Landsat satellite images, we quantify changes in global surface water over the past 32 years at 30-metre resolution. We record the months and years when water was present, where occurrence changed and what form changes took in terms of seasonality and persistence. Between 1984 and 2015 permanent surface water has disappeared from an area of almost 90,000 square kilometres, roughly equivalent to that of Lake Superior, though new permanent bodies of surface water covering 184,000 square kilometres have formed elsewhere. All continental regions show a net increase in permanent water, except Oceania, which has a fractional (one per cent) net loss. Much of the increase is from reservoir filling, although climate change is also implicated. Loss is more geographically concentrated than gain. Over 70 per cent of global net permanent water loss occurred in the Middle East and Central Asia, linked to drought and human actions including river diversion or damming and unregulated withdrawal. Losses in Australia and the USA linked to long-term droughts are also evident. This globally consistent, validated data set shows that impacts of climate change and climate oscillations on surface water occurrence can be measured and that evidence can be gathered to show how surface water is altered by human activities. We anticipate that this freely available data will improve the modelling of surface forcing, provide evidence of state and change in wetland ecotones (the transition areas between biomes), and inform water-management decision-making.

PAHs behavior in surface water and groundwater of the Yellow River estuary: Evidence from isotopes and hydrochemistry.

PubMed

Li, Jing; Li, Fadong; Liu, Qiang

2017-07-01

Large-scale irrigation projects have impacted the regional surface-groundwater interactions in the North China Plain (NCP). Given this concern, the aim of this study is to evaluate levels of PAH pollution, identify the sources of the PAHs, analyze the influence of surface-groundwater interactions on PAH distribution, and propose urgent management strategies for PAHs in China's agricultural areas. PAH concentrations, hydrochemical indicators and stable isotopic compositions (δ 18 O and δ 2 H) were determined for surface water (SW) and groundwater (GW) samples. PAHs concentrations in surface water and groundwater varied from 11.84 to 393.12 ng/L and 8.51-402.84 ng/L, respectively, indicating mild pollution. The seasonal variations showed the following trend: PAHs in surface water at the low-water phase > PAHs in groundwater at the low-water phase > PAHs in surface water at the high-water phase > PAHs in groundwater at the high-water phase. Hydrochemical and δ 18 O value of most groundwater samples distributed between the Yellow River and seawater. The mean value of mixture ratio of the Yellow River water recharge to the groundwater was 65%, few anomalous sites can reach to 90%. Surface-groundwater interactions influence the spatial distribution of PAHs in the study area. In light of the ongoing serious pollution, management practices for source control, improved control technologies, and the construction of a monitoring network to warn of increased risk are urgently needed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Pharmaceuticals and personal care products (PPCPs) and artificial sweeteners (ASs) in surface and ground waters and their application as indication of wastewater contamination.

PubMed

Yang, Yuan-Yuan; Zhao, Jian-Liang; Liu, You-Sheng; Liu, Wang-Rong; Zhang, Qian-Qian; Yao, Li; Hu, Li-Xin; Zhang, Jin-Na; Jiang, Yu-Xia; Ying, Guang-Guo

2018-03-01

We systematically investigated the occurrence and distribution of 93 pharmaceuticals and personal care products (PPCPs) and 5 artificial sweeteners (ASs) in surface water and groundwater of Dongjiang River basin in south China. In surface water, 52 compounds were detected with median concentrations ranging from 0.06ng/L to 504ng/L, while in groundwater, 33 compounds were detected with concentrations up to 4580ng/L for acesulfame. PPCPs and ASs were widely detected in the surface water and groundwater samples, which indicated contamination by domestic wastewater in the surface water and groundwater of Dongjiang River basin. Temporal and spatial variations of the detected chemicals were observed in surface water. Acesulfame, sucralose and cyclamate can be used as wastewater indicators to imply contamination in groundwater caused by domestic wastewater due to their hydrophilicity, anthropogenic sources and ubiquity in groundwater. Moreover, the detection of the readily degradable ASs, cyclamate, was a strong indication of untreated wastewater in groundwater. Sucralose was found to be a suitable wastewater indicator to reflect domestic wastewater contamination in surface water and groundwater qualitatively and quantitatively, and it can be used to evaluate wastewater burden in surface water and groundwater of Dongjiang River basin. The wastewater burden data from this survey implied serious contamination in surface water and groundwater by domestic wastewater at Shima River, a tributary of the Dongjiang River. The findings from this study suggest that the selected labile and conservative chemicals can be used as indication of wastewater contamination for aquatic environments qualitatively and quantitatively. Copyright © 2017 Elsevier B.V. All rights reserved.

Dynamic Bubble Surface Tension Measurements in Northwest Atlantic Seawater

NASA Astrophysics Data System (ADS)

Kieber, D. J.; Long, M. S.; Keene, W. C.; Kinsey, J. D.; Frossard, A. A.; Beaupre, S. R.; Duplessis, P.; Maben, J. R.; Lu, X.; Chang, R.; Zhu, Y.; Bisgrove, J.

2017-12-01

Numerous reports suggest that most organic matter (OM) associated with newly formed primary marine aerosol (PMA) originates from the sea-surface microlayer. However, surface-active OM rapidly adsorbs onto bubble surfaces in the water column and is ejected into the atmosphere when bubbles burst at the air-water interface. Here we present dynamic surface tension measurements of bubbles produced in near surface seawater from biologically productive and oligotrophic sites and in deep seawater collected from 2500 m in the northwest Atlantic. In all cases, the surface tension of bubble surfaces decreased within seconds after the bubbles were exposed to seawater. These observations demonstrate that bubble surfaces are rapidly saturated by surfactant material scavenged from seawater. Spatial and diel variability in bubble surface evolution indicate corresponding variability in surfactant concentrations and/or composition. Our results reveal that surface-active OM is found throughout the water column, and that at least some surfactants are not of recent biological origin. Our results also support the hypothesis that the surface microlayer is a minor to negligible source of OM associated with freshly produced PMA.

Water interactions with condensed organic phases: a combined experimental and theoretical study of molecular-level processes

NASA Astrophysics Data System (ADS)

Johansson, Sofia M.; Kong, Xiangrui; Thomson, Erik S.; Papagiannakopoulos, Panos; Pettersson, Jan B. C.; Lovrić, Josip; Toubin, Céline

2016-04-01

Water uptake on aerosol particles modifies their chemistry and microphysics with important implications for air quality and climate. A large fraction of the atmospheric aerosol consists of organic aerosol particles or inorganic particles with condensed organic components. Here, we combine laboratory studies using the environmental molecular beam (EMB) method1 with molecular dynamics (MD) simulations to characterize water interactions with organic surfaces in detail. The over-arching aim is to characterize the mechanisms that govern water uptake, in order to guide the development of physics-based models to be used in atmospheric modelling. The EMB method enables molecular level studies of interactions between gases and volatile surfaces at near ambient pressure,1 and the technique may provide information about collision dynamics, surface and bulk accommodation, desorption and diffusion kinetics. Molecular dynamics simulations provide complementary information about the collision dynamics and initial interactions between gas molecules and the condensed phase. Here, we focus on water interactions with condensed alcohol phases that serve as highly simplified proxies for systems in the environment. Gas-surface collisions are in general found to be highly inelastic and result in efficient surface accommodation of water molecules. As a consequence, surface accommodation of water can be safely assumed to be close to unity under typical ambient conditions. Bulk accommodation is inefficient on solid alcohol and the condensed materials appear to produce hydrophobic surface structures, with limited opportunities for adsorbed water to form hydrogen bonds with surface molecules. Accommodation is significantly more efficient on the dynamic liquid alcohol surfaces. The results for n-butanol (BuOH) are particularly intriguing where substantial changes in water accommodation taking place over a 10 K interval below and above the BuOH melting point.2 The governing mechanisms for the observed water accommodation are discussed based on the combined EMB and MD results. The studies illustrate that the detailed surface properties of the condensed organic phase may substantially modify water uptake, with potential implications for the properties and action of aerosols and clouds in the Earth system. References: 1. X.R. Kong, E. S. Thomson, P. Papagiannakopoulos, S.M. Johansson, and J.B.C. Pettersson, Water Accommodation on Ice and Organic Surfaces: Insights from Environmental Molecular Beam Experiments. J. Phys. Chem. B 118 (2014) 13378-13386. 2. P. Papagiannakopoulos, X. Kong, E. S. Thomson, N. Marković, and J. B. C. Pettersson, Surface Transformations and Water Uptake on Liquid and Solid Butanol near the Melting Temperature. J. Phys. Chem. C 117 (2013) 6678-6685.

Surface Treatment on Physical Properties and Biocompatibility of Orthodontic Power Chains

PubMed Central

Cheng, H. C.; Chen, M. S.; Peng, B. Y.; Lin, W. T.; Wang, Y. H.

2017-01-01

The conventional orthodontic power chain, often composed of polymer materials, has drawbacks such as a reduction of elasticity owing to water absorption as well as surface discoloration and staining resulting from food or beverages consumed by the patient. The goal of this study was to develop a surface treatment (nanoimprinting) for orthodontic power chains and to alleviate their shortcomings. A concave template (anodic alumina) was manufactured by anodization process using pure aluminum substrate by employing the nanoimprinting process. Convex nanopillars were fabricated on the surface of orthodontic power chains, resulting in surface treatment. Distinct parameters of the nanoimprinting process (e.g., imprinting temperature, imprinting pressure, imprinting time, and demolding temperature) were used to fabricate nanopillars on the surface of orthodontic power chains. The results of this study showed that the contact angle of the power chains became larger after surface treatment. In addition, the power chains changed from hydrophilic to hydrophobic. The power chain before surface treatment without water absorption had a water absorption rate of approximately 4%, whereas a modified chain had a water absorption rate of approximately 2%–4%. Furthermore, the color adhesion of the orthodontic power chains after surface modification was less than that before surface modification. PMID:28540299

Superamphiphobic Surfaces Prepared by Coating Multifunctional Nanofluids.

PubMed

Esmaeilzadeh, Pouriya; Sadeghi, Mohammad Taghi; Bahramian, Alireza; Fakhroueian, Zahra; Zarbakhsh, Ali

2016-11-23

Construction of surfaces with the capability of repelling both water and oil is a challenging issue. We report the superamphiphobic properties of mineral surfaces coated with nanofluids based on synthesized Co-doped and Ce-doped Barium Strontium Titanate (CoBST and CeBST) nanoparticles and fluorochemicals of trichloro(1H,1H,2H,2H-perfluorooctyl)silane (PFOS) and polytetrafluoroethylene (PTFE). Coating surfaces with these nanofluids provides both oil (with surface tensions as low as 23 mN/m) and water repellency. Liquids with high surface tension (such as water and ethylene glycol) roll off the coated surface without tilting. A water drop released from 8 mm above the coated surface undergoes first a lateral displacement from its trajectory and shape deformation, striking the surface after 23 ms, bouncing and rolling off freely. These multifunctional coating nanofluids impart properties of self-cleaning. Applications include coating surfaces where cleanliness is paramount such as in hospitals and domestic environments as well as the maintenance of building facades and protection of public monuments from weathering. These superamphiphobic-doped nanofluids have thermal stability up to 180 °C; novel industrial applications include within fracking and the elimination of condensate blockage in gas reservoirs.

Correlation between Surface Tension and Water Activity in New Particle Formation

NASA Astrophysics Data System (ADS)

Daskalakis, E.; Salameh, A.

2016-12-01

The impact of aerosol properties on cloud dynamics and the radiative balance of the atmosphere relies on the parametrizations of cloud droplet formation. Such parametrization is based on equilibrium thermodynamics proposed by Köhler in 1936. There is considerable debate in the literature on the importance of factors like the surface tension depression or the water activity decrease for the correct parametrization. To gain fundamental insight into New Particle Formation (NPF), or Cloud Condensation Nuclei (CCN) activation one has to study microscopic properties of aqueous droplets, involving surface and bulk dynamics. The surface tension of droplets can be associated with the effects from Organic Matter (OM), whereas the static dielectric constant of water reflects the structure and dynamics of ions within solutions and can present a measure of water activity. In this study we employ Molecular Dynamics Simulations on aquatic droplets that contain surface active OM (acetaldehyde, methylglyoxal) and salts. We give insight into the dynamics of aquatic droplets with radials of 3.6nm at a level of detail that is not accessible experimentally (J. Phys. Chem. C 2016, 120:11508). We propose that as the surface tension of an aquatic droplet is decreased in the presence of surface-active OM, the water activity is affected as well. This is due to the fact that the water dipoles are oriented based on the salt morphology within the droplet. We suggest that the surface tension depression can be accompanied by the water activity change. This can be associated with the possible effects of surface-active species in terms of salt morphology transitions within an aerosol at the NPF and early particle growth time scales. Based on this study, surface-active OM seems important in controlling (a) the salt morphology transitions within a nucleus during NPF and particle growth and (b) a correlation between surface activity and water activity of ionic aquatic droplets. The latter correlation could be a fundamental property to consider when assessing NPF and the Köhler theory.

Ceres: predictions for near-surface water ice stability and implications for plume generating processes

USGS Publications Warehouse

Titus, Timothy N.

2015-01-01

This paper will constrain the possible sources and processes for the formation of recently observed H2O vapor plumes above the surface of the dwarf planet Ceres. Two hypotheses have been proposed: (1) cryovolcanism where the water source is the mantle and the heating source is still unknown or (2) comet-like sublimation where near-surface water ice is vaporized by seasonally increasing solar insolation. We test hypothesis #2, comet-like near-surface sublimation, by using a thermal model to examine the stability of water-ice in the near surface. For a reasonable range of physical parameters (thermal inertia, surface roughness, slopes), we find that water ice is only stable at latitudes higher than ~40-60 degrees. These results indicate that either (a) the physical properties of Ceres are unlike our expectations or (b) an alternative to comet-like sublimation, such as the cryovolcanism hypothesis, must be invoked.

Behavior of severely supercooled water drops impacting on superhydrophobic surfaces

NASA Astrophysics Data System (ADS)

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

2014-11-01

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

Method to identify wells that yield water that will be replaced by water from the Colorado River downstream from Laguna Dam in Arizona and California

USGS Publications Warehouse

Owen-Joyce, Sandra J.; Wilson, Richard P.; Carpenter, Michael C.; Fink, James B.

2000-01-01

Accounting for the use of Colorado River water is required by the U.S. Supreme Court decree, 1964, Arizona v. California. Water pumped from wells on the flood plain and from certain wells on alluvial slopes outside the flood plain is presumed to be river water and is accounted for as Colorado River water. The accounting-surface method developed for the area upstream from Laguna Dam was modified for use downstream from Laguna Dam to identify wells outside the flood plain of the lower Colorado River that yield water that will be replaced by water from the river. Use of the same method provides a uniform criterion of identification for all users pumping water from wells by determining if the static water-level elevation in the well is above or below the elevation of the accounting surface. Wells that have a static water-level elevation equal to or below the accounting surface are presumed to yield water that will be replaced by water from the Colorado River. Wells that have a static water-level elevation above the accounting surface are presumed to yield river water stored above river level. The method is based on the concept of a river aquifer and an accounting surface within the river aquifer. The river aquifer consists of permeable sediments and sedimentary rocks that are hydraulically connected to the Colorado River so that water can move between the river and the aquifer in response to withdrawal of water from the aquifer or differences in water-level elevations between the river and the aquifer. The subsurface limit of the river aquifer is the nearly impermeable bedrock of the bottom and sides of the basins that underlie the Yuma area and adjacent valleys. The accounting surface represents the elevation and slope of the unconfined static water table in the river aquifer outside the flood plain of the Colorado River that would exist if the river were the only source of water to the river aquifer. The accounting surface was generated by using water-surface profiles of the Colorado River from Laguna Dam to about the downstream limit of perennial flow at Morelos Dam. The accounting surface extends outward from the edges of the flood plain to the subsurface boundary of the river aquifer. Maps at a scale of 1:100,000 show the extent of the river aquifer and elevation of the accounting surface downstream from Laguna Dam in Arizona and California.

Assessment of stream water chemistry and impact of geothermal fluid in the up-Buyuk Menderes Basin, Turkey.

PubMed

Davraz, Aysen; Aksever, Fatma; Afsin, Mustafa

2017-12-01

The discharge of geothermal fluid into the natural water environment may lead to serious damages. In this study, the impact of geothermal waste water on surface water has been investigated in the up-Buyuk Menderes River, Turkey. Thermal return water from district heating and from thermal bath in the Sandıklı region were the most important source of major solutes and trace elements to the up-Buyuk Menderes River and tributaries. The thermal contribution causes a drastic increase in Na, SO 4 ions, EC, and temperature of surface waters. The concentrations of As, Al, B, Fe, Cr, Li, S, P, Pb, U, Mn, and Zn are increasing dramatically downstream of thermal water inputs in the Kufi Creek tributary. In addition to natural thermal water inputs, water quality was impacted by anthropogenic trace and major element inputs from surface waters. The increased of some trace elements (Al, As, B, Cu, Cd, Fe, Mn, P, U) in surface water are related to anthropogenic activities such as agricultural activities, sewage effluents, and stockyards in the study area. Additionally, surface water quality of the up-Buyuk Menderes River and tributaries was evaluated according to standards given by the Environmental Protection Agency of both Turkey and USA. Our study demonstrates the influence of thermal water inputs on water quality of surface waters.

40 CFR 279.54 - Used oil management.

Code of Federal Regulations, 2014 CFR

2014-07-01

... the soil, groundwater, or surface water. (d) Secondary containment for existing aboveground tanks... containment system from migrating out of the system to the soil, groundwater, or surface water. (e) Secondary... out of the system to the soil, groundwater, or surface water. (f) Labels. (1) Containers and...

40 CFR 279.54 - Used oil management.

Code of Federal Regulations, 2011 CFR

2011-07-01

... the soil, groundwater, or surface water. (d) Secondary containment for existing aboveground tanks... containment system from migrating out of the system to the soil, groundwater, or surface water. (e) Secondary... out of the system to the soil, groundwater, or surface water. (f) Labels. (1) Containers and...

40 CFR 279.54 - Used oil management.

Code of Federal Regulations, 2012 CFR

2012-07-01

... the soil, groundwater, or surface water. (d) Secondary containment for existing aboveground tanks... containment system from migrating out of the system to the soil, groundwater, or surface water. (e) Secondary... out of the system to the soil, groundwater, or surface water. (f) Labels. (1) Containers and...

40 CFR 279.54 - Used oil management.

Code of Federal Regulations, 2013 CFR

2013-07-01

... the soil, groundwater, or surface water. (d) Secondary containment for existing aboveground tanks... containment system from migrating out of the system to the soil, groundwater, or surface water. (e) Secondary... out of the system to the soil, groundwater, or surface water. (f) Labels. (1) Containers and...

40 CFR 279.64 - Used oil storage.

Code of Federal Regulations, 2010 CFR

2010-07-01

... soil, groundwater, or surface water. (d) Secondary containment for existing aboveground tanks. Existing... system to the soil, groundwater, or surface water. (e) Secondary containment for new aboveground tanks... containment system from migrating out of the system to the soil, groundwater, or surface water. (f) Labels. (1...

40 CFR 279.64 - Used oil storage.

Code of Federal Regulations, 2011 CFR

2011-07-01

... soil, groundwater, or surface water. (d) Secondary containment for existing aboveground tanks. Existing... system to the soil, groundwater, or surface water. (e) Secondary containment for new aboveground tanks... containment system from migrating out of the system to the soil, groundwater, or surface water. (f) Labels. (1...

Economic Impacts of Surface Mining on Household Drinking Water Supplies

EPA Science Inventory

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

Control and characterization of textured, hydrophobic ionomer surfaces

NASA Astrophysics Data System (ADS)

Wang, Xueyuan

Polymer thin films are of increasing interest in many industrial and technological applications. Superhydrophobic, self-cleaning surfaces have attracted a lot of attention for their application in self-cleaning, anti-sticking coatings, stain resistance, or anti-contamination surfaces in diverse technologies, including medical, transportation, textiles, electronics and paints. This thesis focuses on the preparation of nanometer to micrometer-size particle textured surfaces which are desirable for super water repellency. Textured surfaces consisting of nanometer to micrometer-sized lightly sulfonated polystyrene ionomer (SPS) particles were prepared by rapid evaporation of the solvent from a dilute polymer solution cast onto silica. The effect of the solvent used to spin coat the film, the molecular weight of the ionomer, and the rate of solvent evaporation were investigated. The nano-particle or micron-particle textured ionomer surfaces were prepared by either spin coating or solution casting ionomer solutions at controlled evaporation rates. The surface morphologies were consistent with a spinodal decomposition mechanism where the surface first existed as a percolated-like structure and then ripened into droplets if molecular mobility was retained for sufficient time. The SPS particles or particle aggregates were robust and resisted deformation even after annealing at 120°C for one week. The water contact angles on as-prepared surfaces were relatively low, ~ 90° since the polar groups in ionomer reduce the surface hydrophobicity. After chemical vapor deposition of 1H,1H,2H,2H-perfluorooctyltrichlorosilane, the surface contact angles increased to ~ 109° on smooth surfaces and ~140° on the textured surfaces. Water droplets stuck to these surfaces even when tilted 90 degrees. Superhydrophobic surfaces were prepared by spraying coating ionomer solutions and Chemical Vapor Deposition (CVD) of 1H,1H,2H,2H-perfluorooctyltrichlorosilane onto textured surfaces. The surfaces after CVD of silane exhibited water contact angle of 152° and the water droplet stuck to the surfaces without falling even when tilted upside down. This kind of sticky superhydrophobic surface would have potential applications in no-loss transport of liquid, and cleaning robots.

Water adsorption on surface-modified cellulose nanocrystals

NASA Astrophysics Data System (ADS)

Wei, Zonghui; Sinko, Robert; Keten, Sinan; Luijten, Erik

Cellulose nanocrystals (CNCs) have attracted much attention as a filler phase for polymer nanocomposites due to their impressive mechanical properties, low cost, and environmental sustainability. Despite their promise for this application, there are still numerous obstacles that prevent optimal performance of CNC-polymer nanocomposites, such as poor filler dispersion and high levels of water absorption. One way to mitigate these negative effects is to modify CNC surfaces. Computational approaches can be utilized to obtain direct insight into the properties of modified CNC surfaces and probe the interactions of CNCs with other materials to facilitate the experimental design of nanocomposites. We use atomistic grand-canonical Monte Carlo simulations to study how surface modification of ion-exchanged sulfated cellulose nanocrystals (Na-CNCs) impacts water adsorption. We find that methyl(triphenyl)phosphonium-exchanged CNCs adsorb less water than Na-CNCs at the same relative humidity, supporting recent experimental dynamic vapor sorption measurements. By characterizing the distribution and configuration of water molecules near the modified CNC surfaces we determine how surface modifications disrupt CNC-water interactions.

Application of Geographic Information System Methods to Identify Areas Yielding Water that will be Replaced by Water from the Colorado River in the Vidal and Chemehuevi Areas, California, and the Mohave Mesa Area, Arizona

USGS Publications Warehouse

Spangler, Lawrence E.; Angeroth, Cory E.; Walton, Sarah J.

2008-01-01

Relations between the elevation of the static water level in wells and the elevation of the accounting surface within the Colorado River aquifer in the vicinity of Vidal, California, the Chemehuevi Indian Reservation, California, and on Mohave Mesa, Arizona, were used to determine which wells outside the flood plain of the Colorado River are presumed to yield water that will be replaced by water from the Colorado River. Wells that have a static water-level elevation equal to or below the elevation of the accounting surface are presumed to yield water that will be replaced by water from the Colorado River. Geographic Information System (GIS) interpolation tools were used to produce maps of areas where water levels are above, below, and near (within ? 0.84 foot) the accounting surface. Calculated water-level elevations and interpolated accounting-surface elevations were determined for 33 wells in the vicinity of Vidal, 16 wells in the Chemehuevi area, and 35 wells on Mohave Mesa. Water-level measurements generally were taken in the last 10 years with steel and electrical tapes accurate to within hundredths of a foot. A Differential Global Positioning System (DGPS) was used to determine land-surface elevations to within an operational accuracy of ? 0.43 foot, resulting in calculated water-level elevations having a 95-percent confidence interval of ? 0.84 foot. In the Vidal area, differences in elevation between the accounting surface and measured water levels range from -2.7 feet below to as much as 17.6 feet above the accounting surface. Relative differences between the elevation of the water level and the elevation of the accounting surface decrease from west to east and from north to south. In the Chemehuevi area, differences in elevation range from -3.7 feet below to as much as 8.7 feet above the accounting surface, which is established at 449.6 feet in the vicinity of Lake Havasu. In all of the Mohave Mesa area, the water-level elevation is near or below the elevation of the accounting surface. Differences in elevation between water levels and the accounting surface range from -0.2 to -11.3 feet, with most values exceeding -7.0 feet. In general, the ArcGIS Triangulated Irregular Network (TIN) Contour and Natural Neighbor tools reasonably represent areas where the elevation of water levels in wells is above, below, and near (within ? 0.84 foot) the elevation of the accounting surface in the Vidal and Chemehuevi study areas and accurately delineate areas around outlying wells and where anomalies exist. The TIN Contour tool provides a strict linear interpolation while the Natural Neighbor tool provides a smoothed interpolation. Using the default options in ArcGIS, the Inverse Distance Weighted (IDW) and Spline tools also reasonably represent areas above, below, and near the accounting surface in the Vidal and Chemehuevi areas. However, spatial extent of and boundaries between areas above, below, and near the accounting surface vary among the GIS methods, which results largely from the fundamentally different mathematical approaches used by these tools. The limited number and spatial distribution of wells in comparison to the size of the areas, and the locations and relative differences in elevation between water levels and the accounting surface of wells with anomalous water levels also influence the contouring by each of these methods. Qualitatively, the Natural Neighbor tool appears to provide the best representation of the difference between water-level and accounting-surface elevations in the study areas, on the basis of available well data.

Electrospray surface-enhanced Raman spectroscopy (ES-SERS) for probing surface chemical compositions of atmospherically relevant particles

NASA Astrophysics Data System (ADS)

Gen, Masao; Chan, Chak K.

2017-11-01

We present electrospray surface-enhanced Raman spectroscopy (ES-SERS) as a new approach to measuring the surface chemical compositions of atmospherically relevant particles. The surface-sensitive SERS is realized by electrospraying Ag nanoparticle aerosols over analyte particles. Spectral features at v(SO42-), v(C-H) and v(O-H) modes were observed from the normal Raman and SERS measurements of laboratory-generated supermicron particles of ammonium sulfate (AS), AS mixed with succinic acid (AS / SA) and AS mixed with sucrose (AS / sucrose). SERS measurements showed strong interaction (or chemisorption) between Ag nanoparticles and surface aqueous sulfate [SO42-] with [SO42-]AS / sucrose > [SO42-]AS / SA > [SO42-]AS. Enhanced spectra of the solid AS and AS / SA particles revealed the formation of surface-adsorbed water on their surfaces at 60 % relative humidity. These observations of surface aqueous sulfate and adsorbed water demonstrate a possible role of surface-adsorbed water in facilitating the dissolution of sulfate from the bulk phase into its water layer(s). Submicron ambient aerosol particles collected in Hong Kong exhibited non-enhanced features of black carbon and enhanced features of sulfate and organic matter (carbonyl group), indicating an enrichment of sulfate and organic matter on the particle surface.

Update of the Accounting Surface Along the Lower Colorado River

USGS Publications Warehouse

Wiele, Stephen M.; Leake, Stanley A.; Owen-Joyce, Sandra J.; McGuire, Emmet H.

2008-01-01

The accounting-surface method was developed in the 1990s by the U.S. Geological Survey, in cooperation with the Bureau of Reclamation, to identify wells outside the flood plain of the lower Colorado River that yield water that will be replaced by water from the river. This method was needed to identify which wells require an entitlement for diversion of water from the Colorado River and need to be included in accounting for consumptive use of Colorado River water as outlined in the Consolidated Decree of the United States Supreme Court in Arizona v. California. The method is based on the concept of a river aquifer and an accounting surface within the river aquifer. The study area includes the valley adjacent to the lower Colorado River and parts of some adjacent valleys in Arizona, California, Nevada, and Utah and extends from the east end of Lake Mead south to the southerly international boundary with Mexico. Contours for the original accounting surface were hand drawn based on the shape of the aquifer, water-surface elevations in the Colorado River and drainage ditches, and hydrologic judgment. This report documents an update of the original accounting surface based on updated water-surface elevations in the Colorado River and drainage ditches and the use of simple, physically based ground-water flow models to calculate the accounting surface in four areas adjacent to the free-flowing river.

The impacts of surface polarity on the solubility of nanoparticle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhu, Jianzhuo; Su, Jiguo, E-mail: jiguosu@ysu.edu.cn; Ou, Xinwen

In order to study the dependence of water solubility and hydration behavior of nanoparticles on their surface polarity, we designed polar nanoparticles with varying surface polarity by assigning atomic partial charge to the surface of C60. The water solubility of the nanoparticle is enhanced by several orders of magnitude after the introduction of surface polarity. Nevertheless, when the atomic partial charge grows beyond a certain value (q{sub M}), the solubility continuously decreases to the level of nonpolar nanoparticle. It should be noted that such q{sub M} is comparable with atomic partial charge of a variety of functional groups. The hydrationmore » behaviors of nanoparticles were then studied to investigate the non-monotonic dependence of solubility on the surface polarity. The interaction between the polar nanoparticle and the hydration water is stronger than the nonpolar counterpart, which should facilitate the dissolution of the nanoparticles. On the other hand, the surface polarity also reduces the interaction of hydration water with the other water molecules and enhances the interaction between the nanoparticles which may hinder their dispersion. Besides, the introduction of surface polarity disturbs and even rearranges the hydration structure of nonpolar nanoparticle. Interestingly, the polar nanoparticle with less ordered hydration structure tends to have higher water solubility.« less

Adsorption and structure of water on kaolinite surfaces: possible insight into ice nucleation from grand canonical monte carlo calculations.

PubMed

Croteau, T; Bertram, A K; Patey, G N

2008-10-30

Grand canonical Monte Carlo calculations are used to determine water adsorption and structure on defect-free kaolinite surfaces as a function of relative humidity at 235 K. This information is then used to gain insight into ice nucleation on kaolinite surfaces. Results for both the SPC/E and TIP5P-E water models are compared and demonstrate that the Al-surface [(001) plane] and both protonated and unprotonated edges [(100) plane] strongly adsorb at atmospherically relevant relative humidities. Adsorption on the Al-surface exhibits properties of a first-order process with evidence of collective behavior, whereas adsorption on the edges is essentially continuous and appears dominated by strong water lattice interactions. For the protonated and unprotonated edges no structure that matches hexagonal ice is observed. For the Al-surface some of the water molecules formed hexagonal rings. However, the a o lattice parameter for these rings is significantly different from the corresponding constant for hexagonal ice ( Ih). A misfit strain of 14.0% is calculated between the hexagonal pattern of water adsorbed on the Al-surface and the basal plane of ice Ih. Hence, the ring structures that form on the Al-surface are not expected to be good building-blocks for ice nucleation due to the large misfit strain.

Estimated use of water in South Dakota, 2005

USGS Publications Warehouse

Carter, Janet M.; Neitzert, Kathleen M.

2008-01-01

During 2005, withdrawals from ground-water and surface-water sources in South Dakota for the eight categories of offstream use totaled about 500 million gallons per day (Mgal/d). Of total withdrawals, about 271 Mgal/d was withdrawn from ground water and about 230 Mgal/d was withdrawn from surface water. The largest use of water in South Dakota during 2005 was irrigation, which accounted for about 58 percent of the total water withdrawn, followed by public supply, which accounted for about 20 percent of withdrawals. Public-supply systems served about 666,210 people, or about 86 percent of South Dakota's population in 2005. Public-supply systems withdrew about 100 Mgal/d in 2005. Ground-water withdrawals accounted for about 66 percent of the total withdrawals (66 Mgal/d), and surface-water withdrawals accounted for about 34 percent of total withdrawals (35 Mgal/d). Total public-supply withdrawals averaged about 151 gallons per day (gal/d) per capita. About 65 percent of the public-supply water was used for domestic purposes, and the average per capita domestic use was 99 gal/d. Self-supplied domestic withdrawals were about 8 Mgal/d, all of which was from ground water. About 109,750 people obtained household water from private wells in 2005, and per capita use was about 70 gal/d. Industrial self-supplied water use during 2005 was about 4 Mgal/d, of which about 98 percent was from ground water and about 2 percent was from surface water. Total withdrawals for thermoelectric use were about 5 Mgal/d, of which about 1 Mgal/d was from ground water and about 4 Mgal/d was from surface water. Total mining water use was about 10 Mgal/d, of which about 5 Mgal/d came from ground water and about 6 Mgal/d came from surface water. Total livestock water use was about 48 Mgal/d, of which about 19 Mgal/d came from ground water and about 28 Mgal/d came from surface water. Total aquaculture use was about 33 Mgal/d, of which about 19 Mgal/d came from ground water and about 14 Mgal/d came from surface water. Irrigation withdrawals during 2005 totaled about 292 Mgal/d, of which about 149 Mgal/d was from ground-water sources and about 143 Mgal/d was from surface-water sources. An estimated 421,830 acres was irrigated during 2005. Of the total acres irrigated, 298,160 acres was irrigated by sprinkler application and 123,670 acres was irrigated by surface (or flood) application. The only instream use reported for South Dakota was for hydroelectric power generation. During 2005, about 68,400 Mgal/d was used by the hydroelectric powerplants to generate about 3,688 gigawatt-hours of electricity. Total water use in South Dakota decreased by about 25 percent (175 Mgal/d) between 1985 and 2005 despite an increase in the State's population of about 70,000 people. Total ground-water use increased slightly (about 21 Mgal/d) between 1985 and 2005, whereas surface-water use decreased by about 195 Mgal/d. The decreases in both total use and surface-water use are mostly attributable to decreases in irrigation water use. Total irrigation water use decreased by about 168 Mgal/d between 1985 and 2005, and surface-water irrigation use decreased by about 204 Mgal/d. Ground-water irrigation use increased by about 36 Mgal/d between 1985 and 2005. Water use for public supply increased about 20 Mgal/d between 1985 and 2005, and the population served by public suppliers increased by about 118,000 people. In contrast, the number of people relying on private wells for domestic use decreased by about 48,000 between 1985 and 2005. All self-supplied domestic water use in 2005 was supplied by ground water. Total domestic use decreased about 8 Mgal/d between 1985 and 2005.

Intermittent surface water connectivity: Fill and spill vs. fill and merge dynamics

USGS Publications Warehouse

Leibowitz, Scott G.; Mushet, David M.; Newton, Wesley E.

2016-01-01

Intermittent surface connectivity can influence aquatic systems, since chemical and biotic movements are often associated with water flow. Although often referred to as fill and spill, wetlands also fill and merge. We examined the effects of these connection types on water levels, ion concentrations, and biotic communities of eight prairie pothole wetlands between 1979 and 2015. Fill and spill caused pulsed surface water connections that were limited to periods following spring snow melt. In contrast, two wetlands connected through fill and merge experienced a nearly continuous, 20-year surface water connection and had completely coincident water levels. Fill and spill led to minimal convergence in dissolved ions and macroinvertebrate composition, while these constituents converged under fill and merge. The primary factor determining differences in response was duration of the surface water connection between wetland pairs. Our findings suggest that investigations into the effects of intermittent surface water connections should not consider these connections generically, but need to address the specific types of connections. In particular, fill and spill promotes external water exports while fill and merge favors internal storage. The behaviors of such intermittent connections will likely be accentuated under a future with more frequent and severe climate extremes.

Flood recovery maps for the White River in Bethel, Stockbridge, and Rochester, Vermont, and the Tweed River in Stockbridge and Pittsfield, Vermont, 2014

USGS Publications Warehouse

Olson, Scott A.

2015-01-01

Eighteen high-water marks from Tropical Storm Irene were available along the studied reaches. The discharges in the Tropical Storm Irene HEC–RAS model were adjusted so that the resulting water-surface elevations matched the high-water mark elevations along the study reaches. This allowed for an estimation of the water-surface profile throughout the study area resulting from Tropical Storm Irene. From a comparison of the estimated water-surface profile of Tropical Storm Irene to the water-surface profiles of the 1- and 0.2-percent AEP floods, it was determined that the high-water elevations resulting from Tropical Storm Irene exceeded the estimated 1-percent AEP flood throughout the White River and Tweed River study reaches and exceeded the estimated 0.2-percent AEP flood in 16.7 of the 28.6 study reach miles. The simulated water-surface profiles were then combined with a geographic information system digital elevation model derived from light detection and ranging (lidar) data having a 18.2-centimeter vertical accuracy at the 95-percent confidence level and 1-meter horizontal resolution to delineate the area flooded for each water-surface profile.

A Raman spectroscopy study on the effects of intermolecular hydrogen bonding on water molecules absorbed by borosilicate glass surface

NASA Astrophysics Data System (ADS)

Li, Fabing; Li, Zhanlong; Wang, Ying; Wang, Shenghan; Wang, Xiaojun; Sun, Chenglin; Men, Zhiwei

2018-05-01

The structural forms of water/deuterated water molecules located on the surface of borosilicate capillaries have been first investigated in this study on the basis of the Raman spectral data obtained at different temperatures and under atmospheric pressure for molecules in bulk and also for molecules absorbed by borosilicate glass surface. The strongest two fundamental bands locating at 3063 cm-1 (2438 cm-1) in the recorded Raman spectra are assigned here to the Osbnd H (Osbnd D) bond stretching vibrations and they are compared with the corresponding bands observed at 3124 cm-1 (2325 cm-1) in the Raman spectrum of ice Ih. Our spectroscopic observations have indicated that the structure of water and deuterated water molecules on borosilicate surface is similar to that of ice Ih (hexagonal phase of ice). These observations have also indicated that water molecules locate on the borosilicate surface so as to construct a bilayer structure and that strong and weak intermolecular hydrogen bonds are formed between water/deuterated molecules and silanol groups on borosilicate surface. In accordance with these findings, water and deuterated water molecules at the interface of capillary have a higher melting temperature.

Performance of a pilot showcase of different wetland systems in an urban setting in Singapore.

PubMed

Quek, B S; He, Q H; Sim, C H

2015-01-01

The Alexandra Wetlands, part of PUB's Active, Beautiful, Clean Waters (ABC Waters) Programme, showcase a surface flow wetland, an aquatic pond and a sub-surface flow wetland on a 200 m deck built over an urban drainage canal. Water from the canal is pumped to a sedimentation basin, before flowing in parallel to the three wetlands. Water quality monitoring was carried out monthly from April 2011 to December 2012. The order of removal efficiency is sub-surface flow (81.3%) >aquatic pond (58.5%) >surface flow (50.7%) for total suspended solids (TSS); sub-surface (44.9%) >surface flow (31.9%) >aquatic pond (22.0%) for total nitrogen (TN); and surface flow (56.7%) >aquatic pond (39.8%) >sub-surface flow (5.4%) for total phosphorus (TP). All three wetlands achieved the Singapore stormwater treatment objectives (STO) for TP removal, but only the sub-surface flow wetland met the STO for TSS, and none met the STO for TN. Challenges in achieving satisfactory performance include inconsistent feed water quality, undesirable behaviour such as fishing, release of pets and feeding of animals in the wetlands, and canal dredging during part of the monitoring period. As a pilot showcase, the Alexandra Wetlands provide useful lessons for implementing multi-objective wetlands in an urban setting.

Pattern of dental caries experience on tooth surfaces in an adult population.

PubMed

Hopcraft, Matthew Scott; Morgan, Michael Vivian

2006-06-01

To determine the pattern of caries experience across teeth and surfaces in an adult population depending on age and exposure to water fluoridation. Between November 2002 and March 2003 a total of 973 subjects aged 17-51 years had a clinical examination using visual and tactile criteria. Subsequent to this examination, bitewing radiographs were taken and viewed separately. Approximal and occlusal surfaces of molars and premolars were examined on the radiographs. Caries experience was relatively low, with mean DMFS scores of 3.21, 5.12, 9.61, 13.04 and 24.35 for subjects aged 17-20, 21-25, 26-30, 31-35 and 36-51 years respectively. The first molar teeth had the greatest caries experience, and occlusal surfaces had more caries experience than approximal surfaces. Subjects with a lifetime exposure to fluoridated drinking water had significantly lower caries experience than those who had no exposure to fluoridated drinking water. This study showed that caries prevalence, although relatively low in the study population, was found predominantly in occlusal surfaces, with an increasing prevalence in approximal surfaces of posterior teeth in older subjects. Subjects with a lifetime exposure to fluoridated drinking water had a lower level of caries experience than those with no exposure to fluoridated drinking water, and this was more noticeable in approximal surfaces than occlusal surfaces.

Water transport mechanism through open capillaries analyzed by direct surface modifications on biological surfaces

NASA Astrophysics Data System (ADS)

Ishii, Daisuke; Horiguchi, Hiroko; Hirai, Yuji; Yabu, Hiroshi; Matsuo, Yasutaka; Ijiro, Kuniharu; Tsujii, Kaoru; Shimozawa, Tateo; Hariyama, Takahiko; Shimomura, Masatsugu

2013-10-01

Some small animals only use water transport mechanisms passively driven by surface energies. However, little is known about passive water transport mechanisms because it is difficult to measure the wettability of microstructures in small areas and determine the chemistry of biological surfaces. Herein, we developed to directly analyse the structural effects of wettability of chemically modified biological surfaces by using a nanoliter volume water droplet and a hi-speed video system. The wharf roach Ligia exotica transports water only by using open capillaries in its legs containing hair- and paddle-like microstructures. The structural effects of legs chemically modified with a self-assembled monolayer were analysed, so that the wharf roach has a smart water transport system passively driven by differences of wettability between the microstructures. We anticipate that this passive water transport mechanism may inspire novel biomimetic fluid manipulations with or without a gravitational field.

High volume hydraulic fracturing operations: potential impacts on surface water and human health.

PubMed

Mrdjen, Igor; Lee, Jiyoung

2016-08-01

High volume, hydraulic fracturing (HVHF) processes, used to extract natural gas and oil from underground shale deposits, pose many potential hazards to the environment and human health. HVHF can negatively affect the environment by contaminating soil, water, and air matrices with potential pollutants. Due to the relatively novel nature of the process, hazards to surface waters and human health are not well known. The purpose of this article is to link the impacts of HVHF operations on surface water integrity, with human health consequences. Surface water contamination risks include: increased structural failure rates of unconventional wells, issues with wastewater treatment, and accidental discharge of contaminated fluids. Human health risks associated with exposure to surface water contaminated with HVHF chemicals include increased cancer risk and turbidity of water, leading to increased pathogen survival time. Future research should focus on modeling contamination spread throughout the environment, and minimizing occupational exposure to harmful chemicals.

Surface Water Records of Colorado

USGS Publications Warehouse

U.S. Geological Survey, Water Resources Division

1962-01-01

The surface-water records for the 1962 water year for gaging stations and miscellaneous sites within the State of Colorado are given in this report. For convenience there are also included records for a few pertinent gaging stations in bordering States. The records were collected and computed by the Water Resources Division of the U.S. Geological Survey, under the direction of J. W. Odell, district engineer, Surface Water Branch.

Sensory Ecology of Water Detection by Bats: A Field Experiment

PubMed Central

Russo, Danilo; Cistrone, Luca; Jones, Gareth

2012-01-01

Bats face a great risk of dehydration, so sensory mechanisms for water recognition are crucial for their survival. In the laboratory, bats recognized any smooth horizontal surface as water because these provide analogous reflections of echolocation calls. We tested whether bats also approach smooth horizontal surfaces other than water to drink in nature by partly covering watering troughs used by hundreds of bats with a Perspex layer mimicking water. We aimed 1) to confirm that under natural conditions too bats mistake any horizontal smooth surface for water by testing this on large numbers of individuals from a range of species and 2) to assess the occurrence of learning effects. Eleven bat species mistook Perspex for water relying chiefly on echoacoustic information. Using black instead of transparent Perspex did not deter bats from attempting to drink. In Barbastella barbastellus no echolocation differences occurred between bats approaching the water and the Perspex surfaces respectively, confirming that bats perceive water and Perspex to be acoustically similar. The drinking attempt rates at the fake surface were often lower than those recorded in the laboratory: bats then either left the site or moved to the control water surface. This suggests that bats modified their behaviour as soon as the lack of drinking reward had overridden the influence of echoacoustic information. Regardless of which of two adjoining surfaces was covered, bats preferentially approached and attempted to drink from the first surface encountered, probably because they followed a common route, involving spatial memory and perhaps social coordination. Overall, although acoustic recognition itself is stereotyped and its importance in the drinking process overwhelming, our findings point at the role of experience in increasing behavioural flexibility under natural conditions. PMID:23133558

76 FR 13175 - Pacific Gas and Electric Company; Notice of Application for Amendment of License and Soliciting...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-10

... water surface elevation requirement, pursuant to Article 403 of the Hat Creek Hydroelectric Project. b... Electric Company (PG&E) is requesting a temporary variance of its water surface elevation requirement of... purpose of the water surface elevation of Cassel Pond is to mitigate the new water leakage found on the...

REAL-TIME high-resolution urban surface water flood mapping to support flood emergency management

NASA Astrophysics Data System (ADS)

Guan, M.; Yu, D.; Wilby, R.

2016-12-01

Strong evidence has shown that urban flood risks will substantially increase because of urbanisation, economic growth, and more frequent weather extremes. To effectively manage these risks require not only traditional grey engineering solutions, but also a green management solution. Surface water flood risk maps based on return period are useful for planning purposes, but are limited for application in flood emergencies, because of the spatiotemporal heterogeneity of rainfall and complex urban topography. Therefore, a REAL-TIME urban surface water mapping system is highly beneficial to increasing urban resilience to surface water flooding. This study integrated numerical weather forecast and high-resolution urban surface water modelling into a real-time multi-level surface water mapping system for Leicester City in the UK. For rainfall forecast, the 1km composite rain radar from the Met Office was used, and we used the advanced rainfall-runoff model - FloodMap to predict urban surface water at both city-level (10m-20m) and street-level (2m-5m). The system is capable of projecting 3-hour urban surface water flood, driven by rainfall derived from UK Met Office radar. Moreover, this system includes real-time accessibility mapping to assist the decision-making of emergency responders. This will allow accessibility (e.g. time to travel) from individual emergency service stations (e.g. Fire & Rescue; Ambulance) to vulnerable places to be evaluated. The mapping results will support contingency planning by emergency responders ahead of potential flood events.

Effect of Water Surface Salinity on Evaporation: The Case of a Diluted Buoyant Plume Over the Dead Sea

NASA Astrophysics Data System (ADS)

Mor, Z.; Assouline, S.; Tanny, J.; Lensky, I. M.; Lensky, N. G.

2018-03-01

Evaporation from water bodies strongly depends on surface water salinity. Spatial variation of surface salinity of saline water bodies commonly occurs across diluted buoyant plumes fed by freshwater inflows. Although mainly studied at the pan evaporation scale, the effect of surface water salinity on evaporation has not yet been investigated by means of direct measurement at the scale of natural water bodies. The Dead Sea, a large hypersaline lake, is fed by onshore freshwater springs that form local diluted buoyant plumes, offering a unique opportunity to explore this effect. Surface heat fluxes, micrometeorological variables, and water temperature and salinity profiles were measured simultaneously and directly over the salty lake and over a region of diluted buoyant plume. Relatively close meteorological conditions prevailed in the two regions; however, surface water salinity was significantly different. Evaporation rate from the diluted plume was occasionally 3 times larger than that of the main salty lake. In the open lake, where salinity was uniform with depth, increased wind speed resulted in increased evaporation rate, as expected. However, in the buoyant plume where diluted brine floats over the hypersaline brine, wind speed above a threshold value (˜4 m s-1) caused a sharp decrease in evaporation probably due to mixing of the stratified plume and a consequent increase in the surface water salinity.

Storm water runoff concentration matrix for urban areas.

PubMed

Göbel, P; Dierkes, C; Coldewey, W G

2007-04-01

The infrastructure (roads, sidewalk, commercial and residential structures) added during the land development and urbanisation process is designed to collect precipitation and convey it out of the watershed, typically in existing surface water channels, such as streams and rivers. The quality of surface water, seepage water and ground water is influenced by pollutants that collect on impervious surfaces and that are carried by urban storm water runoff. Heavy metals, e.g. lead (Pb), zinc (Zn), copper (Cu), cadmium (Cd), polycyclic aromatic hydrocarbons (PAH), mineral oil hydrocarbons (MOH) and readily soluble salts in runoff, contribute to the degradation of water. An intensive literature search on the distribution and concentration of the surface-dependent runoff water has been compiled. Concentration variations of several pollutants derived from different surfaces have been averaged. More than 300 references providing about 1300 data for different pollutants culminate in a representative concentration matrix consisting of medians and extreme values. This matrix can be applied to long-term valuations and numerical modelling of storm water treatment facilities.

Map showing general chemical quality of surface water in the Richfield Quadrangle, Utah

USGS Publications Warehouse

Price, Don

1980-01-01

This is one of a series of maps that describe the geology and related natural resources of the Richfield 2° quadrangle, Utah. The purpose of this map is to show the general chemical quality of surface water in the area by ranges of dissolved-solids concentrations.Data used to compile this map were collected by the U.S. Geological Survey in cooperation with the Utah Department of Natural Resources, Division of Water Rights. In those areas where little or no surface-water-quality data are available, ranges of dissolved-solids concentrations of the water are inferred on the basis of such factors as geology (Stokes, 1964), precipitation, topography, known ground-water quality, and water uses – all of which affect the chemical quality of surface water.Additional information about the chemical quality of surface water in various parts of the Richfield 2° quadrangle may be found in the following reports: Hahl and Cabell (1965), Hahl and Mundorff (1968), Stephens (1974, 1976), Cruff and Mower (1976), and Cruff(1977)

Numerical analysis of the bucket surface roughness effects in Pelton turbine

NASA Astrophysics Data System (ADS)

Xiao, Y. X.; Zeng, C. J.; Zhang, J.; Yan, Z. G.; Wang, Z. W.

2013-12-01

The internal flow of a Pelton turbine is quite complex. It is difficult to analyse the unsteady free water sheet flow in the rotating bucket owing to the lack of a sound theory. Affected by manufacturing technique and silt abrasion during the operation, the bucket surface roughness of Pelton turbine may be too great, and thereby influence unit performance. To investigate the effect of bucket roughness on Pelton turbine performance, this paper presents the numerical simulation of the interaction between the jet and the bucket in a Pelton turbine. The unsteady three-dimensional numerical simulations were performed with CFX code by using the SST turbulence model coupling the two-phase flow volume of fluid method. Different magnitude orders of bucket surface roughness were analysed and compared. Unsteady numerical results of the free water sheet flow patterns on bucket surface, torque and unit performance for each bucket surface roughness were generated. The total pressure distribution on bucket surface is used to show the free water sheet flow pattern on bucket surface. By comparing the variation of water sheet flow patterns on bucket surface with different roughness, this paper qualitatively analyses how the bucket surface roughness magnitude influences the impeding effect on free water sheet flow. Comparison of the torque variation of different bucket surface roughness highlighted the effect of the bucket surface roughness on the Pelton turbine output capacity. To further investigate the effect of bucket surface roughness on Pelton turbine performance, the relation between the relative efficiency loss rate and bucket surface roughness magnitude is quantitatively analysed. The result can be used to predict and evaluate the Pelton turbine performance.

Fathoms Below: Propagation of Deep Water-driven Fractures and Implications for Surface Expression and Temporally-varying Activity at Europa

NASA Astrophysics Data System (ADS)

Walker, C. C.; Craft, K.; Schmidt, B. E.

2015-12-01

The fracture and failure of Europa's icy shell are not only observable scars of variable stress and activity throughout its evolution, they also serve key as mechanisms in the interaction of surface and subsurface material, and thus crucial aspects of the study of crustal overturn and ice shell habitability. Galileo images, our best and only reasonable-resolution views of Europa until the Europa Multiple Flyby Mission arrives in the coming decades, illustrates a single snapshot in time in Europa's history from which we deduce many temporally-based hypotheses. One of those hypotheses, which we investigate here, is that sub-surface water-both in the form of Great Lake-sized perched water pockets in the near-surface and the larger global ocean below-drives the deformation, fracture, and failure of the surface. Using Galileo's snapshot in time, we use a 2D/3D hydraulic fracturing model to investigate the propagation of vertical fractures upward into the ice shell, motion of water within and between fractures, and the subsequent break-up of ice over shallow water, forming the chaos regions and other smaller surface features. We will present results from a cohesive fragmentation model to determine the time over which chaos formation occurs, and use a fracking model to determine the time interval required to allow water to escape from basal fractures in the ice shell. In determining the style, energy, and timescale of these processes, we constrain temporal variability in observable activity and topography at the surface. Finally, we compare these results to similar settings on Earth-Antarctica-where we have much higher resolution imagery and observations to better understand how sub-surface water can affect ice surface morphology, which most certainly have implications for future flyby and surface lander exploration.

Inventory of File sref_nmb.t03z.pgrb212.p1.f06.grib2

Science.gov Websites

surface WEASD 6 hour fcst Water Equivalent of Accumulated Snow Depth [kg/m^2] 016 surface APCP 3-6 hour surface WEASD 3-6 hour acc Water Equivalent of Accumulated Snow Depth [kg/m^2] 019 surface CSNOW 6 hour (non-convective) [kg/m^2] 417 surface SNOM 3-6 hour acc Snow Melt [kg/m^2] 418 surface LHTFL 3-6 hour

Inventory of File sref_nmm.t03z.pgrb212.p1.f06.grib2

Science.gov Websites

surface WEASD 6 hour fcst Water Equivalent of Accumulated Snow Depth [kg/m^2] 016 surface APCP 3-6 hour surface WEASD 3-6 hour acc Water Equivalent of Accumulated Snow Depth [kg/m^2] 019 surface CSNOW 6 hour (non-convective) [kg/m^2] 417 surface SNOM 3-6 hour acc Snow Melt [kg/m^2] 418 surface LHTFL 0-6 hour

Development of an Operational Land Water Mask for MODIS Collection 6, and Influence on Downstream Data Products

NASA Technical Reports Server (NTRS)

Carroll, M. L.; DiMiceli, C. M.; Townshend, J. R. G.; Sohlberg, R. A.; Elders, A. I.; Devadiga, S.; Sayer, A. M.; Levy, R. C.

2016-01-01

Data from the Moderate Resolution Imaging Spectro-radiometer (MODIS)on-board the Earth Observing System Terra and Aqua satellites are processed using a land water mask to determine when an algorithm no longer needs to be run or when an algorithm needs to follow a different pathway. Entering the fourth reprocessing (Collection 6 (C6)) the MODIS team replaced the 1 km water mask with a 500 m water mask for improved representation of the continental surfaces. The new water mask represents more small water bodies for an overall increase in water surface from 1 to 2 of the continental surface. While this is still a small fraction of the overall global surface area the increase is more dramatic in certain areas such as the Arctic and Boreal regions where there are dramatic increases in water surface area in the new mask. MODIS products generated by the on-going C6 reprocessing using the new land water mask show significant impact in areas with high concentrations of change in the land water mask. Here differences between the Collection 5 (C5) and C6 water masks and the impact of these differences on the MOD04 aerosol product and the MOD11 land surface temperature product are shown.

Characterization of water bodies for mosquito habitat using a multi-sensor approach

NASA Astrophysics Data System (ADS)

Midekisa, A.; Wimberly, M. C.; Senay, G. B.

2012-12-01

Malaria is a major health problem in Ethiopia. Anopheles arabiensis, which inhabits and breeds in a variety of aquatic habitats, is the major mosquito vector for malaria transmission in the region. In the Amhara region of Ethiopia, mosquito breeding sites are heterogeneously distributed. Therefore, accurate characterization of aquatic habitats and potential breeding sites can be used as a proxy to measure the spatial distribution of malaria risk. Satellite remote sensing provides the ability to map the spatial distribution and monitor the temporal dynamics of surface water. The objective of this study is to map the probability of surface water accumulation to identify potential vector breeding sites for Anopheles arabiensis using remote sensing data from sensors at multiple spatial and temporal resolutions. The normalized difference water index (NDWI), which is based on reflectance in the green and the near infrared (NIR) bands were used to estimate fractional cover of surface water. Temporal changes in surface water were mapped using NDWI indices derived from MODIS surface reflectance product (MOD09A1) for the period 2001-2012. Landsat TM and ETM+ imagery were used to train and calibrate model results from MODIS. Results highlighted interannual variation and seasonal changes in surface water that were observed from the MODIS time series. Static topographic indices that estimate the potential for water accumulation were generated from 30 meter Shuttle Radar Topography Mission (SRTM) elevation data. Integrated fractional surface water cover was developed by combining the static topographic indices and dynamic NDWI indices using Geographic Information System (GIS) overlay methods. Accuracy of the results was evaluated based on ground truth data that was collected on presence and absence of surface water immediately after the rainy season. The study provided a multi-sensor approach for mapping areas with a high potential for surface water accumulation that are potential breeding habitats for anopheline mosquitoes. The resulting products are useful for public health decision making towards effective prevention and control of the malaria burden in the Amhara region of Ethiopia.

Water at surfaces with tunable surface chemistries

NASA Astrophysics Data System (ADS)

Sanders, Stephanie E.; Vanselous, Heather; Petersen, Poul B.

2018-03-01

Aqueous interfaces are ubiquitous in natural environments, spanning atmospheric, geological, oceanographic, and biological systems, as well as in technical applications, such as fuel cells and membrane filtration. Where liquid water terminates at a surface, an interfacial region is formed, which exhibits distinct properties from the bulk aqueous phase. The unique properties of water are governed by the hydrogen-bonded network. The chemical and physical properties of the surface dictate the boundary conditions of the bulk hydrogen-bonded network and thus the interfacial properties of the water and any molecules in that region. Understanding the properties of interfacial water requires systematically characterizing the structure and dynamics of interfacial water as a function of the surface chemistry. In this review, we focus on the use of experimental surface-specific spectroscopic methods to understand the properties of interfacial water as a function of surface chemistry. Investigations of the air-water interface, as well as efforts in tuning the properties of the air-water interface by adding solutes or surfactants, are briefly discussed. Buried aqueous interfaces can be accessed with careful selection of spectroscopic technique and sample configuration, further expanding the range of chemical environments that can be probed, including solid inorganic materials, polymers, and water immiscible liquids. Solid substrates can be finely tuned by functionalization with self-assembled monolayers, polymers, or biomolecules. These variables provide a platform for systematically tuning the chemical nature of the interface and examining the resulting water structure. Finally, time-resolved methods to probe the dynamics of interfacial water are briefly summarized before discussing the current status and future directions in studying the structure and dynamics of interfacial water.

Atomistic investigation on the detachment of oil molecules from defective alumina surface

NASA Astrophysics Data System (ADS)

Xie, W. K.; Sun, Y. Z.; Liu, H. T.

2017-12-01

The mechanism of oil detachment from defective alumina surface in aqueous solution was investigated via atomistic molecular dynamics (MD) simulations. Special attention was focused on the effect of surface defect on the oil detachment. Our simulation results suggest that compared with perfect Al2O3 surface, defective substrate surface provides much more sites for the adsorption of oil molecules, thus it has higher oil adsorption energy. However, higher oil-solid adsorption energy does not mean that oil contaminants are much more difficult to be detached. It is found that surface defect could induce the spontaneous imbibition of water molecules, effectively promoting the detachment of oil molecules. Thus, compared with perfect alumina surface, the detachment of oil molecules from defective alumina surface tends to be much easier. Moreover, surface defect could lead to the oil residues inside surface defect. In water solution, the entire detachment process of oil molecules on defective surface consists of following stages, including the early detachment of oil molecules inside surface defect induced by capillary-driven spontaneous imbibition of water molecules, the following conformational change of oil molecules on topmost surface and the final migration of detached oil molecules from solid surface. These findings may help to sufficiently enrich the removal mechanism of oil molecules adhered onto defective solid surface.

Investigation of Water Dissociation and Surface Hydroxyl Stability on Pure and Ni-Modified CoOOH by Ambient Pressure Photoelectron Spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Zhu; Kronawitter, Coleman X.; Waluyo, Iradwikanari

Water adsorption and reaction on pure and Ni-modified CoOOH nanowires were investigated using ambient pressure photoemission spectroscopy (APPES). The unique capabilities of APPES enable us to observe water dissociation and monitor formation of surface species on pure and Ni-modified CoOOH under elevated pressures and temperatures for the first time. Over a large range of pressures (UHV to 1 Torr), water dissociates readily on the pure and Ni-modified CoOOH surfaces at 27 °C. With an increase in H 2O pressure, a greater degree of surface hydroxylation was observed for all samples. At 1 Torr H 2O, ratios of different oxygen speciesmore » indicate a transformation of CoOOH to CoO xH y in pure and Ni-modified CoOOH. In temperature dependent studies, desorption of weakly bound water and surface dehydroxylation were observed with increasing temperature. In conclusion, larger percentages of surface hydroxyl groups at higher temperatures were observed on Ni-modified CoOOH compared to pure CoOOH, which indicates an increased stability of surface hydroxyl groups on these Ni-modified surfaces.« less

Investigation of Water Dissociation and Surface Hydroxyl Stability on Pure and Ni-Modified CoOOH by Ambient Pressure Photoelectron Spectroscopy

DOE PAGES

Chen, Zhu; Kronawitter, Coleman X.; Waluyo, Iradwikanari; ...

2017-09-07

Water adsorption and reaction on pure and Ni-modified CoOOH nanowires were investigated using ambient pressure photoemission spectroscopy (APPES). The unique capabilities of APPES enable us to observe water dissociation and monitor formation of surface species on pure and Ni-modified CoOOH under elevated pressures and temperatures for the first time. Over a large range of pressures (UHV to 1 Torr), water dissociates readily on the pure and Ni-modified CoOOH surfaces at 27 °C. With an increase in H 2O pressure, a greater degree of surface hydroxylation was observed for all samples. At 1 Torr H 2O, ratios of different oxygen speciesmore » indicate a transformation of CoOOH to CoO xH y in pure and Ni-modified CoOOH. In temperature dependent studies, desorption of weakly bound water and surface dehydroxylation were observed with increasing temperature. In conclusion, larger percentages of surface hydroxyl groups at higher temperatures were observed on Ni-modified CoOOH compared to pure CoOOH, which indicates an increased stability of surface hydroxyl groups on these Ni-modified surfaces.« less

A statistical examination of Nimbus 7 SMMR data and remote sensing of sea surface temperature, liquid water content in the atmosphere and surfaces wind speed

NASA Technical Reports Server (NTRS)

Prabhakara, C.; Wang, I.; Chang, A. T. C.; Gloersen, P.

1982-01-01

Nimbus 7 Scanning Multichannel Microwave Radiometer (SMMR) brightness temperature measurements over the global oceans have been examined with the help of statistical and empirical techniques. Such analyses show that zonal averages of brightness temperature measured by SMMR, over the oceans, on a large scale are primarily influenced by the water vapor in the atmosphere. Liquid water in the clouds and rain, which has a much smaller spatial and temporal scale, contributes substantially to the variability of the SMMR measurements within the latitudinal zones. The surface wind not only increases the surface emissivity but through its interactions with the atmosphere produces correlations, in the SMMR brightness temperature data, that have significant meteorological implications. It is found that a simple meteorological model can explain the general characteristics of the SMMR data. With the help of this model methods to infer over the global oceans, the surface temperature, liquid water content in the atmosphere, and surface wind speed are developed. Monthly mean estimates of the sea surface temperature and surface winds are compared with the ship measurements. Estimates of liquid water content in the atmosphere are consistent with earlier satellite measurements.

Saltwater icephobicity: Influence of surface chemistry on saltwater icing

PubMed Central

Carpenter, Katherine; Bahadur, Vaibhav

2015-01-01

Most studies on icephobicity focus on ice formation with pure water. This manuscript presents studies to understand the influence of surfaces on saltwater ice nucleation and propagation. Experiments are conducted to quantify the influence of surface chemistry on saltwater ice nucleation and to understand the utility of superhydrophobic surfaces for saltwater icephobicity. These experiments are conducted with pure water and two sodium chloride solutions, which represent the salinity of seawater and briny produced water. It is seen that the presence of salt slows down the ice front propagation velocity significantly. Saltwater droplet impact dynamics on superhydrophobic surfaces are also different from pure water. Saltwater droplets retract more and a greater fraction of impacting liquid is repelled from the superhydrophobic surface. It is seen that the greater bounciness of saltwater droplets is a result of slower ice nucleation propagation kinetics. These experiments indicate that superhydrophobic surfaces will have better resistance to impact icing with saltwater than pure water and can remain useful at temperatures as low as −40 °C. Overall, this work is a starting point for further studies on heterogeneous nucleation in saltwater and serves as a bridge between the widely studied freshwater icephobic surfaces and saltwater-related applications. PMID:26626958

Drop-wise and film-wise water condensation processes occurring on metallic micro-scaled surfaces

NASA Astrophysics Data System (ADS)

Starostin, Anton; Valtsifer, Viktor; Barkay, Zahava; Legchenkova, Irina; Danchuk, Viktor; Bormashenko, Edward

2018-06-01

Water condensation was studied on silanized (superhydrophobic) and fluorinated (superoleophobic) micro-rough aluminum surfaces of the same topography. Condensation on superhydrophobic surfaces occurred via film-wise mechanism, whereas on superoleophobic surfaces it was drop-wise. The difference in the pathways of condensation was attributed to the various energy barriers separating the Cassie and Wenzel wetting states on the investigated surfaces. The higher barriers inherent for superoleophobic surfaces promoted the drop-wise condensation. Triple-stage kinetics of growth of droplets condensed on superoleophobic surfaces is reported and discussed.

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

USGS Publications Warehouse

Vining, Kevin C.; Cates, Steven W.

2006-01-01

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

Groundwater infiltration, surface water inflow and sewerage exfiltration considering hydrodynamic conditions in sewer systems.

PubMed

Karpf, Christian; Hoeft, Stefan; Scheffer, Claudia; Fuchs, Lothar; Krebs, Peter

2011-01-01

Sewer systems are closely interlinked with groundwater and surface water. Due to leaks and regular openings in the sewer system (e.g. combined sewer overflow structures with sometimes reverse pressure conditions), groundwater infiltration and surface water inflow as well as exfiltration of sewage take place and cannot be avoided. In the paper a new hydrodynamic sewer network modelling approach will be presented, which includes--besides precipitation--hydrographs of groundwater and surface water as essential boundary conditions. The concept of the modelling approach and the models to describe the infiltration, inflow and exfiltration fluxes are described. The model application to the sewerage system of the City of Dresden during a flood event with complex conditions shows that the processes of infiltration, exfiltration and surface water inflows can be described with a higher reliability and accuracy, showing that surface water inflow causes a pronounced system reaction. Further, according to the simulation results, a high sensitivity of exfiltration rates on the in-sewer water levels and a relatively low influence of the dynamic conditions on the infiltration rates were found.

Modeling Water Redistribution in a Near-Surface Arid Soil

NASA Astrophysics Data System (ADS)

Luo, Y.; Ghezzehei, T. A.; Berli, M.; Dijkema, J.; Koonce, J.

2017-12-01

Desert soils cover about one third of the Earth's land surface and play an important role in the ecology and hydrology of arid environments. Despite their large extend, relatively little is known about their near-surface (top centimeters to meter) water dynamics. Recent studies by Koonce (2016) and Dijkema et al. (2017) shed light on the water dynamics of near-surface arid soil but also revealed some of the challenges to simulate the water redistribution in arid soils. The goal of this study was to improve water redistribution simulations in near-surface arid soils by employing more advanced hydraulic conductivity functions. Expanding on the work by Dijkema et al. (2017), we used a HYDRUS-1D model with different hydraulic conductivity functions to simulate water redistribution within the soil as a function of precipitation, evaporation and drainage. Model calculations were compared with measured data from the SEPHAS weighing lysimeters in Boulder City, NV. Preliminary results indicate that water redistribution simulations of near-surface arid soils can be improved by using hydraulic conductivity functions that can capture capillary, film and vapor flow, like for example the Peter-Durner-Iden (PDI) model.

A Strontium-Modified Titanium Surface Produced by a New Method and Its Biocompatibility In Vitro

PubMed Central

Liu, Chundong; Zhang, Yanli; Wang, Lichao; Zhang, Xinhua; Chen, Qiuyue; Wu, Buling

2015-01-01

Objective To present a new and effective method of producing titanium surfaces modified with strontium and to investigate the surface characteristics and in vitro biocompatibility of titanium (Ti) surfaces modified with strontium (Sr) for bone implant applications. Materials and Methods Sr-modified Ti surfaces were produced by sequential treatments with NaOH, strontium acetate, heat and water. The surface characteristics and the concentration of the Sr ions released from the samples were examined. Cell adhesion, morphology and growth were investigated using osteoblasts isolated from the calvaria of neonatal Sprague-Dawley rats. Expression of osteogenesis-related genes and proteins was examined to assess the effect of the Sr-modified Ti surfaces on osteoblasts. Results The modified titanium surface had a mesh structure with significantly greater porosity, and approximately5.37±0.35at.% of Sr was incorporated into the surface. The hydrophilicity was enhanced by the incorporation of Sr ions and water treatment. The average amounts of Sr released from the Sr-modified plates subjected to water treatment were slight higher than the plates without water treatment. Sr promoted cellular adhesion, spreading and growth compared with untreated Ti surfaces. The Sr-modified Ti plates also promoted expression of osteogenesis-related genes,and expression of OPN and COL-І by osteoblasts. Ti plates heat treated at 700°C showed increased bioactivity in comparison with those treated at 600°C. Water treatment upregulated the expression of osteogenesis-related genes. Conclusions These results show that Sr-modification of Ti surfaces may improve bioactivity in vitro. Water treatment has enhanced the response of osteoblasts. The Sr-modified Ti heat-treated at 700°C exhibited better bioactivity compared with that heated at 600°C. PMID:26529234

A Strontium-Modified Titanium Surface Produced by a New Method and Its Biocompatibility In Vitro.

PubMed

Liu, Chundong; Zhang, Yanli; Wang, Lichao; Zhang, Xinhua; Chen, Qiuyue; Wu, Buling

2015-01-01

To present a new and effective method of producing titanium surfaces modified with strontium and to investigate the surface characteristics and in vitro biocompatibility of titanium (Ti) surfaces modified with strontium (Sr) for bone implant applications. Sr-modified Ti surfaces were produced by sequential treatments with NaOH, strontium acetate, heat and water. The surface characteristics and the concentration of the Sr ions released from the samples were examined. Cell adhesion, morphology and growth were investigated using osteoblasts isolated from the calvaria of neonatal Sprague-Dawley rats. Expression of osteogenesis-related genes and proteins was examined to assess the effect of the Sr-modified Ti surfaces on osteoblasts. The modified titanium surface had a mesh structure with significantly greater porosity, and approximately5.37±0.35at.% of Sr was incorporated into the surface. The hydrophilicity was enhanced by the incorporation of Sr ions and water treatment. The average amounts of Sr released from the Sr-modified plates subjected to water treatment were slight higher than the plates without water treatment. Sr promoted cellular adhesion, spreading and growth compared with untreated Ti surfaces. The Sr-modified Ti plates also promoted expression of osteogenesis-related genes,and expression of OPN and COL-І by osteoblasts. Ti plates heat treated at 700°C showed increased bioactivity in comparison with those treated at 600°C. Water treatment upregulated the expression of osteogenesis-related genes. These results show that Sr-modification of Ti surfaces may improve bioactivity in vitro. Water treatment has enhanced the response of osteoblasts. The Sr-modified Ti heat-treated at 700°C exhibited better bioactivity compared with that heated at 600°C.

Bioinspired Surface Treatments for Improved Decontamination: Silicate-Based Slippery Liquid-Infused Porous Surfaces (SLIPS)

DTIC Science & Technology

2017-07-20

methyl salicylate, dimethyl methylphosphate, and diisopropyl fluorophosphates following treatment of contaminated surfaces with a soapy water solution...and diisopropyl fluorophosphate following treatment of contaminated surfaces with a soapy water solution is reported along with droplet diffusion on...SURFACES (SLIPS) INTRODUCTION The DoD Chemical and Biological Defense Program (CBDP) seeks to provide protection of forces in a contaminated

Wettability, polarity, and water absorption of holm oak leaves: effect of leaf side and age.

PubMed

Fernández, Victoria; Sancho-Knapik, Domingo; Guzmán, Paula; Peguero-Pina, José Javier; Gil, Luis; Karabourniotis, George; Khayet, Mohamed; Fasseas, Costas; Heredia-Guerrero, José Alejandro; Heredia, Antonio; Gil-Pelegrín, Eustaquio

2014-09-01

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 holm oak (Quercus ilex) as a model. By measuring the leaf water potential 24 h after the deposition of water drops onto abaxial and adaxial surfaces, evidence for water penetration through the upper leaf side was gained in young and mature leaves. The structure and chemical composition of the abaxial (always present) and adaxial (occurring only in young leaves) trichomes were analyzed by various microscopic and analytical procedures. The adaxial surfaces were wettable and had a high degree of water drop adhesion in contrast to the highly unwettable and water-repellent abaxial holm oak leaf sides. The surface free energy and solubility parameter decreased with leaf age, with higher values determined for the adaxial sides. All holm oak leaf trichomes were covered with a cuticle. The abaxial trichomes were composed of 8% soluble waxes, 49% cutin, and 43% polysaccharides. For the adaxial side, it is concluded that trichomes and the scars after trichome shedding contribute to water uptake, while the abaxial leaf side is highly hydrophobic due to its high degree of pubescence and different trichome structure, composition, and density. Results are interpreted in terms of water-plant surface interactions, plant surface physical chemistry, and plant ecophysiology. © 2014 American Society of Plant Biologists. All Rights Reserved.

Potentiometric surface of the Floridan Aquifer and its use in management of water resources, St. Johns River Water Management District, Florida

USGS Publications Warehouse

Rodis, Harry George; Munch, D.A.

1983-01-01

The Floridan aquifer supplies most of the fresh groundwater for municipal, industrial, and agricultural uses within the 12,400 sq mi St. Johns River Water Management District. Because of the growing demand for water and the variation in rainfall, resource managers need timely information on short-term and long-term changes in the availability of fresh water. The purpose of this report is to explain potentiometric surface maps and their value in assessing the resource, particularly during drought conditions. The Floridan aquifer is recharged by rainfall falling directly on the outcrop of the aquifer, and, where the aquifer is overlain by the surficial aquifer with the water table above the potentiometric surface of the Floridan, by water infiltrating downward from the overlying surficial aquifer. Water is discharged by pumping and free-flowing wells, springflow, and upward leakage into overlying formations, streams, and lakes or into the ocean. Fluctuations in the potentiometric surface reflect net gains (recharge) or losses (discharge) of water stored in the aquifer. Net gains occur during the wet season (June through September) when recharge exceeds discharge and causes the potentiometric surface to rise in most places. Net losses in storage, and declines in the potentiometric surface, follow during the dry season (October through May) when discharge exceeds recharge. Seasonal changes in the potentiometric surface, based on a 2-yr average of water level measurements during May and September 1977, and May and September 1978, are illustrated. Two of the greater long-term declines in the potentiometric surface have occurred in the growing metropolitan areas of Jacksonville and Orlando-Winter Park, the two largest public suppliers of water in the Water Management District. Municipal pumpage increased in Jacksonville from 37 million gallons per day (mgd) in 1961 to 56 mgd in 1980. The increased pumpage and a deficiency in rainfall of 15.8 inches contributed to a decline in the potentiometric surface of as much as 15 ft. Orlando-Winter Park municipal pumpage increasing from 27 mgd in 1961 to 62 mgd in 1980. The periodic preparation of maps showing changes in the potentiometric surface of the aquifer provide the best base information for both short-term and long-term management of the water resources in the St. Johns River Water Management District. (Lantz-PTT)

Understanding surface-water availability in the Central Valley as a means to projecting future groundwater storage with climate variability

NASA Astrophysics Data System (ADS)

Goodrich, J. P.; Cayan, D. R.

2017-12-01

California's Central Valley (CV) relies heavily on diverted surface water and groundwater pumping to supply irrigated agriculture. However, understanding the spatiotemporal character of water availability in the CV is difficult because of the number of individual farms and local, state, and federal agencies involved in using and managing water. Here we use the Central Valley Hydrologic Model (CVHM), developed by the USGS, to understand the relationships between climatic variability, surface water inputs, and resulting groundwater use over the historical period 1970-2013. We analyzed monthly surface water diversion data from >500 CV locations. Principle components analyses were applied to drivers constructed from meteorological data, surface reservoir storage, ET, land use cover, and upstream inflows, to feed multiple regressions and identify factors most important in predicting surface water diversions. Two thirds of the diversion locations ( 80% of total diverted water) can be predicted to within 15%. Along with monthly inputs, representations of cumulative precipitation over the previous 3 to 36 months can explain an additional 10% of variance, depending on location, compared to results that excluded this information. Diversions in the southern CV are highly sensitive to inter-annual variability in precipitation (R2 = 0.8), whereby more surface water is used during wet years. Until recently, this was not the case in the northern and mid-CV, where diversions were relatively constant annually, suggesting relative insensitivity to drought. In contrast, this has important implications for drought response in southern regions (eg. Tulare Basin) where extended dry conditions can severely limit surface water supplies and lead to excess groundwater pumping, storage loss, and subsidence. In addition to fueling our understanding of spatiotemporal variability in diversions, our ability to predict these water balance components allows us to update CVHM predictions before surface water data are compiled. We can then develop groundwater pumping and storage predictions in real time, and make them available to water managers. In addition, we are working toward future projections by coupling the regional CVHM to downscaled GCM output to assess future scenarios of water availability in this critical region.

Adsorption of surfactant ions and binding of their counterions at an air/water interface.

PubMed

Tagashira, Hiroaki; Takata, Youichi; Hyono, Atsushi; Ohshima, Hiroyuki

2009-01-01

An expression for the surface tension of an aqueous mixed solution of surfactants and electrolyte ions in the presence of the common ions was derived from the Helmholtz free energy of an air/water surface. By applying the equation to experimental data for the surface tension, the adsorption constant of surfactant ions onto the air/water interface, the binding constant of counterions on the surfactants, and the surface potential and surface charge density of the interface were estimated. The adsorption constant and binding constant were dependent on the species of surfactant ion and counterion, respectively. Taking account of the dependence of surface potential and surface charge density on the concentration of electrolyte, it was suggested that the addition of electrolyte to the aqueous surfactant solution brings about the decrease in the surface potential, the increase in the surface density of surfactant ions, and consequently, the decrease in the surface tension. Furthermore, it was found that the configurational entropy plays a predominant role for the surface tension, compared to the electrical work.

Salinity driven oceanographic upwelling

DOEpatents

Johnson, D.H.

1984-08-30

The salinity driven oceanographic upwelling is maintained in a mariculture device that includes a long main duct in the general shape of a cylinder having perforated cover plates at each end. The mariculture device is suspended vertically in the ocean such that one end of the main duct is in surface water and the other end in relatively deep water that is cold, nutrient rich and relatively fresh in comparison to the surface water which is relatively warm, relatively nutrient deficient and relatively saline. A plurality of elongated flow segregating tubes are disposed in the main duct and extend from the upper cover plate beyond the lower cover plate into a lower manifold plate. The lower manifold plate is spaced from the lower cover plate to define a deep water fluid flow path to the interior space of the main duct. Spacer tubes extend from the upper cover plate and communicate with the interior space of the main duct. The spacer tubes are received in an upper manifold plate spaced from the upper cover plate to define a surface water fluid flow path into the flow segregating tubes. A surface water-deep water counterflow is thus established with deep water flowing upwardly through the main duct interior for discharge beyond the upper manifold plate while surface water flows downwardly through the flow segregating tubes for discharge below the lower manifold plate. During such counterflow heat is transferred from the downflowing warm water to the upflowing cold water. The flow is maintained by the difference in density between the deep water and the surface water due to their differences in salinity. The upwelling of nutrient rich deep water is used for marifarming by fertilizing the nutrient deficient surface water. 1 fig.

Salinity driven oceanographic upwelling

DOEpatents

Johnson, David H.

1986-01-01

The salinity driven oceanographic upwelling is maintained in a mariculture device that includes a long main duct in the general shape of a cylinder having perforated cover plates at each end. The mariculture device is suspended vertically in the ocean such that one end of the main duct is in surface water and the other end in relatively deep water that is cold, nutrient rich and relatively fresh in comparison to the surface water which is relatively warm, relatively nutrient deficient and relatively saline. A plurality of elongated flow segregating tubes are disposed in the main duct and extend from the upper cover plate beyond the lower cover plate into a lower manifold plate. The lower manifold plate is spaced from the lower cover plate to define a deep water fluid flow path to the interior space of the main duct. Spacer tubes extend from the upper cover plate and communicate with the interior space of the main duct. The spacer tubes are received in an upper manifold plate spaced from the upper cover plate to define a surface water fluid flow path into the flow segregating tubes. A surface water-deep water counterflow is thus established with deep water flowing upwardly through the main duct interior for discharge beyond the upper manifold plate while surface water flows downwardly through the flow segregating tubes for discharge below the lower manifold plate. During such counterflow heat is transferred from the downflowing warm water to the upflowing cold water. The flow is maintained by the difference in density between the deep water and the surface water due to their differences in salinity. The upwelling of nutrient rich deep water is used for marifarming by fertilizing the nutrient deficient surface water.

A monitoring of chemical contaminants in waters used for field irrigation and livestock watering in the Veneto region (Italy), using bioassays as a screening tool.

PubMed

De Liguoro, Marco; Bona, Mirco Dalla; Gallina, Guglielmo; Capolongo, Francesca; Gallocchio, Federica; Binato, Giovanni; Di Leva, Vincenzo

2014-03-01

In this study, 50 livestock watering sources (ground water) and 50 field irrigation sources (surface water) from various industrialised areas of the Veneto region were monitored for chemical contaminants. From each site, four water samples (one in each season) were collected during the period from summer 2009 through to spring 2010. Surface water samples and ground water samples were first screened for toxicity using the growth inhibition test on Pseudokirchneriella subcapitata and the immobilisation test on Daphnia magna, respectively. Then, based on the results of these toxicity tests, 28 ground water samples and 26 surface water samples were submitted to chemical analysis for various contaminants (insecticides/acaricides, fungicides, herbicides, metals and anions) by means of UPLC-MS(n) HPLC-MS(n), AAS and IEC. With the exception of one surface water sample where the total pesticides concentration was greater than 4 μg L(-1), positive samples (51.9 %) showed only traces (nanograms per liter) of pesticides. Metals were generally under the detection limit. High concentrations of chlorines (up to 692 mg L(-1)) were found in some ground water samples while some surface water samples showed an excess of nitrites (up to 336 mg L(-1)). Detected levels of contamination were generally too low to justify the toxicity recorded in bioassays, especially in the case of surface water samples, and analytical results painted quite a reassuring picture, while tests on P. subcapitata showed a strong growth inhibition activity. It was concluded that, from an ecotoxicological point of view, surface waters used for field irrigation in the Veneto region cannot be considered safe.

Patterned gradient surface for spontaneous droplet transportation and water collection: simulation and experiment

NASA Astrophysics Data System (ADS)

Tan, Xianhua; Zhu, Yiying; Shi, Tielin; Tang, Zirong; Liao, Guanglan

2016-11-01

We demonstrate spontaneous droplet transportation and water collection on wedge-shaped gradient surfaces consisting of alternating hydrophilic and hydrophobic regions. Droplets on the surfaces are modeled and simulated to analyze the Gibbs free energy and free energy gradient distributions. Big half-apex angle and great wettability difference result in considerable free energy gradient, corresponding to large driving force for spontaneous droplet transportation, thus causing the droplets to move towards the open end of the wedge-shaped hydrophilic regions, where the Gibbs free energy is low. Gradient surfaces are then fabricated and tested. Filmwise condensation begins on the hydrophilic regions, forming wedge-shaped tracks for water collection. Dropwise condensation occurs on the hydrophobic regions, where the droplet size distribution and departure diameters are controlled by the width of the regions. Condensate water from both the hydrophilic and hydrophobic regions are collected directionally to the open end of the wedge-shaped hydrophilic regions, agreeing with the simulations. Directional droplet transport and controllable departure diameters make the branched gradient surfaces more efficient than smooth surfaces for water collection, which proves that gradient surfaces are potential in water collection, microfluidic devices, anti-fogging and self-cleaning.

The surface tension of aqueous solutions of some atmospheric water-soluble organic compounds

NASA Astrophysics Data System (ADS)

Tuckermann, Rudolf; Cammenga, Heiko K.

The surface tensions of aqueous solutions of levoglucosan, 3-hydroxybutanoic acid, 3-hydroxybenzoic acid, azelaic acid, pinonic acid, and humic acid have been measured. These compounds are suggested as model substances for the water-soluble organic compounds (WSOC) in atmospheric aerosols and droplets which may play an important role in the aerosol cycle because of their surface-active potentials. The reductions in surface tension induced by single and mixed WSOC in aqueous solution of pure water is remarkable. However, the results of this investigation cannot explain the strong reduction in surface tension in real cloud and fog water samples at concentrations of WSOC below 1 mg/mL.

Carbon and nitrogen biogeochemistry of a Prairie Pothole Wetland, Stutsman County, North Dakota, USA

USGS Publications Warehouse

Holloway, JoAnn M.; Goldhaber, Martin B.; Mills, Christopher T.

2011-01-01

The concentration and form of dissolved organic C (DOC) and N species (NH4+ and NO3-) were investigated as part of a larger hydrogeochemical study of the Cottonwood Lake Study Area within the Prairie Potholes region. Groundwater, pore water and surface wetland water data were used to help characterize the relationships between surface and groundwater with respect to nutrient dynamics. Photosynthesis and subsequent decomposition of vegetation in these hydrologically dynamic wetlands generates a large amount of dissolved C and N, although the subsurface till, derived in part from organic matter rich Pierre Shale, is a likely secondary source of nutrients in deeper groundwater. While surface water DOC concentrations ranged from 2.2 to 4.6 mM, groundwater values were 0.15 mM to 3.7 mM. Greater specific UV absorbance (SUVA254) in the wetland water column and in soil pore waters relative to groundwater indicate more reactive DOC in the surface to near-surface waters. Circumneutral wetlands had greater SUVA254, possibly because of variations in vegetation communities. The dominant inorganic nitrogen species was NH4+ in both wetland water and most ground water samples. The exceptions were 3 wells with NO3- ranging from 38 to 115 μM. Shallow groundwater wells (Well 28 and Well 13S) with greater connection to wetland surface water had greater NH4+ concentrations (1.1 mM and 120 μM) than other well samples (3–90 μM). Pore water nutrient chemistry was more similar to surface water than ground water. Nitrogen results suggest reducing conditions in both groundwater and surface water, possibly due to the microbial uptake of O2 by decaying vegetation in the wetland water column, labile organic C available in shallow groundwater, or the oxidation of pyrite associated with the subsurface.

Water interaction with hydrophobic and hydrophilic soot particles.

PubMed

Popovicheva, Olga; Persiantseva, Natalia M; Shonija, Natalia K; DeMott, Paul; Koehler, Kirsten; Petters, Markus; Kreidenweis, Sonia; Tishkova, Victoria; Demirdjian, Benjamin; Suzanne, Jean

2008-05-07

The interaction of water with laboratory soots possessing a range of properties relevant for atmospheric studies is examined by two complementary methods: gravimetrical measurement of water uptake coupled with chemical composition and porosity analysis and HTDMA (humidified tandem differential mobility analyzer) inference of water uptake accompanied by separate TEM (transmission electron microscopy) analysis of single particles. The first method clarifies the mechanism of water uptake for bulk soot and allows the classification of soot with respect to its hygroscopicity. The second method highlights the dependence of the soot aerosol growth factor on relative humidity (RH) for quasi-monodisperse particles. Hydrophobic and hydrophilic soot are qualitatively defined by their water uptake and surface polarity: laboratory soot particles are thus classified from very hydrophobic to very hydrophilic. Thermal soot particles produced from natural gas combustion are classified as hydrophobic with a surface of low polarity since water is found to cover only half of the surface. Graphitized thermal soot particles are proposed for comparison as extremely hydrophobic and of very low surface polarity. Soot particles produced from laboratory flame of TC1 aviation kerosene are less hydrophobic, with their entire surface being available for statistical monolayer water coverage at RH approximately 10%. Porosity measurements suggest that, initially, much of this surface water resides within micropores. Consequently, the growth factor increase of these particles to 1.07 at RH > 80% is attributed to irreversible swelling that accompanies water uptake. Hysteresis of adsorption/desorption cycles strongly supports this conclusion. In contrast, aircraft engine soot, produced from burning TC1 kerosene in a gas turbine engine combustor, has an extremely hydrophilic surface of high polarity. Due to the presence of water soluble organic and inorganic material it can be covered by many water layers even below water saturation conditions. This soot demonstrates a gradual diameter growth factor (D(wet)/D(dry)) increase up to 1.22 at 93% relative humidity, most likely due to the presence of single particles with water soluble material heterogeneously distributed over their surface.

Foulant characteristics comparison in recycling cooling water system makeup by municipal reclaimed water and surface water in power plant.

PubMed

Ping, Xu; Jing, Wang; Yajun, Zhang; Jie, Wang; Shuai, Si

2015-01-01

Due to water shortage, municipal reclaimed water rather than surface water was replenished into recycling cooling water system in power plants in some cities in China. In order to understand the effects of the measure on carbon steel corrosion, characteristics of two kinds of foulant produced in different systems were studied in the paper. Differences between municipal reclaimed water and surface water were analyzed firstly. Then, the weight and the morphology of two kinds of foulant were compared. Moreover, other characteristics including the total number of bacteria, sulfate reducing bacteria, iron bacteria, extracellular polymeric substance (EPS), protein (PN), and polysaccharide (PS) in foulant were analyzed. Based on results, it could be concluded that microbial and corrosive risk would be increased when the system replenished by municipal reclaimed water instead of surface water.

Engineered Multifunctional Surfaces for Fluid Handling

NASA Technical Reports Server (NTRS)

Thomas, Chris; Ma, Yonghui; Weislogel, Mark

2012-01-01

Designs incorporating variations in capillary geometry and hydrophilic and/or antibacterial surface properties have been developed that are capable of passive gas/liquid separation and passive water flow. These designs can incorporate capillary grooves and/or surfaces arranged to create linear and circumferential capillary geometry at the micro and macro scale, radial fin configurations, micro holes and patterns, and combinations of the above. The antibacterial property of this design inhibits the growth of bacteria or the development of biofilm. The hydrophilic property reduces the water contact angle with a treated substrate such that water spreads into a thin layer atop the treated surface. These antibacterial and hydrophilic properties applied to a thermally conductive surface, combined with capillary geometry, create a novel heat exchanger capable of condensing water from a humid, two-phase water and gas flow onto the treated heat exchanger surfaces, and passively separating the condensed water from the gas flow in a reduced gravity application. The overall process to generate the antibacterial and hydrophilic properties includes multiple steps to generate the two different surface properties, and can be divided into two major steps. Step 1 uses a magnetron-based sputtering technique to implant the silver atoms into the base material. A layer of silver is built up on top of the base material. Completion of this step provides the antibacterial property. Step 2 uses a cold-plasma technique to generate the hydrophilic surface property on top of the silver layer generated in Step 1. Completion of this step provides the hydrophilic property in addition to the antibacterial property. Thermally conductive materials are fabricated and then treated to create the antibacterial and hydrophilic surface properties. The individual parts are assembled to create a condensing heat exchanger with antibacterial and hydrophilic surface properties and capillary geometry, which is capable of passive phase separation in a reduced gravity application. The plasma processes for creating antibacterial and hydrophilic surface properties are suitable for applications where water is present on an exposed surface for an extended time, such that bacteria or biofilms could form, and where there is a need to manage the water on the surface. The processes are also suitable for applications where only the hydrophilic property is needed. In particular, the processes are applicable to condensing heat exchangers (CHXs), which benefit from the antibacterial properties as well as the hydrophilic properties. Water condensing onto the control surfaces of the CHX will provide the moist conditions necessary for the growth of bacteria and the formation of biofilms. The antibacterial properties of the base layer (silver) will mitigate and prevent the growth of bacteria and formation of biofilms that would otherwise reduce the CHX performance. In addition, the hydrophilic properties reduce the water contact angle and prevent water droplets from bridging between control surfaces. Overall, the hydrophilic properties reduce the pressure drop across the CHX.

Exchange of E. coli from the foreshore reservoir to surface waters during intensified wave conditions

NASA Astrophysics Data System (ADS)

Malott, S. S.; Vogel, L. J.; Edge, T.; O'Carroll, D. M.; Robinson, C. E.

2014-12-01

In recent years a number of studies have suggested that foreshore sand and porewater can act as a non-point source of microbial contamination to adjacent surface waters. Fecal indicator bacteria (FIB) can be released from the sand into the surface water through sand erosion or wave-induced porewater flows leading to FIB detachment. Although regression models often show that there is a strong correlation between wave events and high E. coli in surface waters, there is limited understanding of the mechanisms by which E. coli is transported from the subsurface foreshore reservoir (sand and porewater) to surface waters during wave events. An improved understanding of the transport mechanisms will facilitate the development of better water quality exceedences predictions. Detailed groundwater flow, sand level and E. coli measurements were conducted at Ipperwash Beach, Lake Huron (Ontario) for three wave events during the 2014 bathing season to evaluate the relative contribution of sand erosion and wave-induced pore water flow in transporting E. coli from the subsurface reservoir to the shallow waters. As expected, results indicate increased E. coli concentrations in ankle and waist deep surface water during periods of increased wave activity (wave height > 0.5m). Considerable sand erosion from the foreshore may have contributed to these increased surface water concentrations. The E. coli concentrations in the foreshore reservoir generally decreased as the wave height intensified, while E. coli concentrations in upshore sand and porewater locations increased.

Integrated Water Flow Model (IWFM), A Tool For Numerically Simulating Linked Groundwater, Surface Water And Land-Surface Hydrologic Processes

NASA Astrophysics Data System (ADS)

Dogrul, E. C.; Brush, C. F.; Kadir, T. N.

2006-12-01

The Integrated Water Flow Model (IWFM) is a comprehensive input-driven application for simulating groundwater flow, surface water flow and land-surface hydrologic processes, and interactions between these processes, developed by the California Department of Water Resources (DWR). IWFM couples a 3-D finite element groundwater flow process and 1-D land surface, lake, stream flow and vertical unsaturated-zone flow processes which are solved simultaneously at each time step. The groundwater flow system is simulated as a multilayer aquifer system with a mixture of confined and unconfined aquifers separated by semiconfining layers. The groundwater flow process can simulate changing aquifer conditions (confined to unconfined and vice versa), subsidence, tile drains, injection wells and pumping wells. The land surface process calculates elemental water budgets for agricultural, urban, riparian and native vegetation classes. Crop water demands are dynamically calculated using distributed soil properties, land use and crop data, and precipitation and evapotranspiration rates. The crop mix can also be automatically modified as a function of pumping lift using logit functions. Surface water diversions and groundwater pumping can each be specified, or can be automatically adjusted at run time to balance water supply with water demand. The land-surface process also routes runoff to streams and deep percolation to the unsaturated zone. Surface water networks are specified as a series of stream nodes (coincident with groundwater nodes) with specified bed elevation, conductance and stage-flow relationships. Stream nodes are linked to form stream reaches. Stream inflows at the model boundary, surface water diversion locations, and one or more surface water deliveries per location are specified. IWFM routes stream flows through the network, calculating groundwater-surface water interactions, accumulating inflows from runoff, and allocating available stream flows to meet specified or calculated deliveries. IWFM utilizes a very straight-forward input file structure, allowing rapid development of complex simulations. A key feature of IWFM is a new algorithm for computation of groundwater flow across element faces. Enhancements to version 3.0 include automatic time-tracking of input and output data sets, linkage with the HEC-DSS database, and dynamic crop allocation using logit functions. Utilities linking IWFM to the PEST automated calibration suite are also available. All source code, executables and documentation are available for download from the DWR web site. IWFM is currently being used to develop hydrologic simulations of California's Central Valley (C2VSIM); the west side of California's San Joaquin Valley (WESTSIM); Butte County, CA; Solano County, CA; Merced County, CA; and the Oregon side of the Walla Walla River Basin.

Streaks Of Colored Water Indicate Surface Airflows

NASA Technical Reports Server (NTRS)

Wilcox, Floyd J., Jr.

1994-01-01

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

43 CFR 11.64 - Injury determination phase-testing and sampling methods.

Code of Federal Regulations, 2010 CFR

2010-10-01

... paragraphs (b), (c), (d), (e), and (f) of this section. (b) Surface water resources. (1) Testing and sampling for injury to surface water resources shall be performed using methodologies described in the... for surface water resources shall be conducted in accordance with methods that are generally accepted...

43 CFR 11.64 - Injury determination phase-testing and sampling methods.

Code of Federal Regulations, 2011 CFR

2011-10-01

... paragraphs (b), (c), (d), (e), and (f) of this section. (b) Surface water resources. (1) Testing and sampling for injury to surface water resources shall be performed using methodologies described in the... for surface water resources shall be conducted in accordance with methods that are generally accepted...

Nutrient sampling slam: high resolution surface-water sampling in streams reveals patterns in groundwater chemistry and flow paths

EPA Science Inventory

The groundwater–surface water interface (GSWI), consisting of shallow groundwater adjacent to stream channels, is a hot spot for nitrogen removal processes, a storage zone for other solutes, and a target for restoration activities. Characterizing groundwater-surface water intera...

IMPROVING THE QUALITY, AVAILABILITY AND SUSTAINABILITY OF DRINKING WATER SUPPLIES THROUGH ANTIFOULING AND ANTISCALING DESALINATION MEMBRANES

EPA Science Inventory

Surface modification with the selected polymers is expected to reduce the fouling and scaling propensity of desalination membranes by strongly binding water at the membrane surface. Foulants will interact with this bound water layer and not with the membrane surface itself....

40 CFR 258.27 - Surface water requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 26 2013-07-01 2013-07-01 false Surface water requirements. 258.27 Section 258.27 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES CRITERIA FOR MUNICIPAL SOLID WASTE LANDFILLS Operating Criteria § 258.27 Surface water requirements. MSWLF units shall not: (a) Cause a discharge of...

75 FR 18500 - Guidance on Improving EPA Review of Appalachian Surface Coal Mining Operations under the Clean...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-12

... of Appalachian Surface Coal Mining Operations under the Clean Water Act, National Environmental... Appalachian Surface Coal Mining Operations under the Clean Water Act, National Environmental Policy Act, and... coal mining operations under the Clean Water Act, National Environmental Policy Act, and the...

Dragonfly: Exploring Titan's Surface with a New Frontiers Relocatable Lander

NASA Astrophysics Data System (ADS)

Barnes, Jason W.; Turtle, Elizabeth P.; Trainer, Melissa G.; Lorenz, Ralph

2017-10-01

We proposed to the NASA New Frontiers 4 mission call a lander to assess Titan's prebiotic chemistry, evaluate its habitability, and search for biosignatures on its surface. Titan as an Ocean World is ideal for the study of prebiotic chemical processes and the habitability of an extraterrestrial environment due to its abundant complex carbon-rich chemistry and because both liquid water and liquid hydrocarbons can occur on its surface. Transient liquid water surface environments can be created by both impacts and cryovolcanic processes. In both cases, the water could mix with surface organics to form a primordial soup. The mission would sample both organic sediments and water ice to measure surface composition, achieving surface mobility by using rotors to take off, fly, and land at new sites. The Dragonfly rotorcraft lander can thus convey a single capable instrument suite to multiple locations providing the capability to explore diverse locations 10s to 100s of kilometers apart to characterize the habitability of Titan's environment, investigate how far prebiotic chemistry has progressed, and search for chemical signatures indicative of water- and/or hydrocarbon-based life.

The Value of GRACE Data in Improving, Assessing and Evaluating Land Surface and Climate Models

NASA Astrophysics Data System (ADS)

Yang, Z.

2011-12-01

I will review how the Gravity Recovery and Climate Experiment (GRACE) satellite measurements have improved land surface models that are developed for weather, climate, and hydrological studies. GRACE-derived terrestrial water storage (TWS) changes have been successfully used to assess and evaluate the improved representations of land-surface hydrological processes such as groundwater-soil moisture interaction, frozen soil and infiltration, and the topographic control on runoff production, as evident in the simulations from the latest Noah-MP, the Community Land Model, and the Community Climate System Model. GRACE data sets have made it possible to estimate key terrestrial water storage components (snow mass, surface water, groundwater or water table depth), biomass, and surface water fluxes (evapotranspiration, solid precipitation, melt of snow/ice). Many of the examples will draw from my Land, Environment and Atmosphere Dynamics group's work on land surface model developments, snow mass retrieval, and multi-sensor snow data assimilation using the ensemble Karman filter and the ensemble Karman smoother. Finally, I will briefly outline some future directions in using GRACE in land surface modeling.

A Probabilistic Analysis of Surface Water Flood Risk in London.

PubMed

Jenkins, Katie; Hall, Jim; Glenis, Vassilis; Kilsby, Chris

2018-06-01

Flooding in urban areas during heavy rainfall, often characterized by short duration and high-intensity events, is known as "surface water flooding." Analyzing surface water flood risk is complex as it requires understanding of biophysical and human factors, such as the localized scale and nature of heavy precipitation events, characteristics of the urban area affected (including detailed topography and drainage networks), and the spatial distribution of economic and social vulnerability. Climate change is recognized as having the potential to enhance the intensity and frequency of heavy rainfall events. This study develops a methodology to link high spatial resolution probabilistic projections of hourly precipitation with detailed surface water flood depth maps and characterization of urban vulnerability to estimate surface water flood risk. It incorporates probabilistic information on the range of uncertainties in future precipitation in a changing climate. The method is applied to a case study of Greater London and highlights that both the frequency and spatial extent of surface water flood events are set to increase under future climate change. The expected annual damage from surface water flooding is estimated to be to be £171 million, £343 million, and £390 million/year under the baseline, 2030 high, and 2050 high climate change scenarios, respectively. © 2017 Society for Risk Analysis.

Velocity and stage data collected in a laboratory flume for water-surface slope determination using a pipe manometer

USGS Publications Warehouse

Lee, Jonathan K.; Visser, H.M.; Jenter, H.L.; Duff, M.P.

2000-01-01

U.S. Geological Survey (USGS) hydrologists and ecologist are conducting studies to quantify vegetative flow resistance in order to improve numerical models of surface-water flow in the Florida Everglades. Water-surface slope is perhaps the most difficult of the flow resistance parameters to measure in the Everglades due to the very low gradients of the topography and flow. In an effort to measure these very small slopes, a unique pipe manometer was developed for the local measurement of water-surface slopes on the order of 1 centimeter per kilometer (cm/km). According to theory, a very precise measurement of centerline velocity obtained inside the pipe manometer should serve as a unique proxy for water-surface slope in the direction of the pipe axis. In order to confirm this theoretical relationship and calibrate the pipe manometer, water-surface elevation and pipe centerline velocity data were simultaneously measured in a set of experiments carried out in the tilting flume at the USGS Hydraulic Laboratory Facility at Stennis Space Center, Mississippi. A description of the instrumentation and methods used to evaluate this technique for measuring water-surface slope as well as a summary of the entire data set is presented.

Real-time direct measurement of liquid (water) evaporation by simple disturbance inhibited interfometry technique

NASA Astrophysics Data System (ADS)

Kim, Yong Gi

2017-11-01

A real-time in-situ interferometry method was proposed to measure water (liquid) evaporation directly over the liquid surface inside the reservoir. The direct evaporation measurement relied on the counting the number of sinusoidal fringes. As the water inside reservoir evaporated, the depth of the water decreases a little thus the optical path length changes. Evaporation signals have been determined as a function of the focusing beam position of the signal beam over the liquid surface. In interferometry technique, the most limiting factors are surface disturbances and vibrations over the liquid surface. This limiting factor was simply inhibited by placing a long cylindrical aluminum tube around the signal beam of the interferometer over the liquid surface. A small diameter cylindrical Al tube diminished vibrations and wind induced surface ripples more effectively than that of the larger one. Water evaporation was successfully measured in real-time with a warm water and cold water even under windy condition with an electric fan. The experimental results demonstrated that the interferometry technique allows determining of liquid evaporation in real-time. Interferometric technique opens up a new possibility of methodology for liquid evaporation measurement even in several environmental disturbances, such as, vibration, surface disturbance, temperature change and windy environments.

Dynamics of two-dimensional monolayer water confined in hydrophobic and charged environments.

PubMed

Kumar, Pradeep; Han, Sungho

2012-09-21

We perform molecular dynamics simulations to study the effect of charged surfaces on the intermediate and long time dynamics of water in nanoconfinements. Here, we use the transferable interaction potential with five points (TIP5P) model of a water molecule confined in both hydrophobic and charged surfaces. For a single molecular layer of water between the surfaces, we find that the temperature dependence of the lateral diffusion constant of water up to very high temperatures remains Arrhenius with a high activation energy. In case of charged surfaces, however, the dynamics of water in the intermediate time regime is drastically modified presumably due to the transient coupling of dipoles of water molecules with electric field fluctuations induced by charges on the confining surfaces. Specifically, the lateral mean square displacements display a distinct super-diffusive behavior at intermediate time scale, defined as the time scale between ballistic and diffusive regimes. This change in the intermediate time-scale dynamics in the charged confinement leads to the enhancement of long-time dynamics as reflected in increasing diffusion constant. We introduce a simple model for a possible explanation of the super-diffusive behavior and find it to be in good agreement with our simulation results. Furthermore, we find that confinement and the surface polarity enhance the low frequency vibration in confinement compared to bulk water. By introducing a new effective length scale of coupling between translational and orientational motions, we find that the length scale increases with the increasing strength of the surface polarity. Further, we calculate the correlation between the diffusion constant and the excess entropy and find a disordering effect of polar surfaces on the structure of water. Finally, we find that the empirical relation between the diffusion constant and the excess entropy holds for a monolayer of water in nanoconfinement.

Intermittent Surface Water Connectivity: Fill and Spill vs. Fill ...

EPA Pesticide Factsheets

Intermittent surface connectivity can influence aquatic systems, since chemical and biotic movements are often associated with water flow. Although often referred to as fill and spill, wetlands also fill and merge. We examined the effects of these connection types on water levels, ion concentrations, and biotic communities of eight prairie pothole wetlands between 1979 and 2015. Fill and spill caused pulsed surface water connections that were limited to periods following spring snow melt. In contrast, two wetlands connected through fill and merge experienced a nearly continuous, 20-year surface water connection and had completely coincident water levels. Fill and spill led to minimal convergence in dissolved ions and macroinvertebrate composition, while these constituents converged under fill and merge. The primary factor determining difference in responses was duration of the surface water connection between wetland pairs. Our findings suggest that investigations into the effects of intermittent surface water connections should not consider these connections generically, but need to address the specific types of connections. In particular, fill and spill promotes external water exports while fill and merge favors internal storage. The behaviors of such intermittent connections will likely be accentuated under a future with more frequent and severe climate extremes. Under the Safe and Sustainable Water Resources National Program, work is being done to qu

Intermittent Surface Water Connectivity: Fill and Spill Vs. Fill ...

EPA Pesticide Factsheets

Intermittent surface connectivity can influence aquatic systems, since chemical and biotic movements are often associated with water flow. Although often referred to as fill and spill, wetlands also fill and merge. We examined the effects of these connection types on water levels, ion concentrations, and biotic communities of eight prairie pothole wetlands between 1979 and 2015. Fill and spill caused pulsed surface water connections that were limited to periods following spring snow melt. In contrast, two wetlands connected through fill and merge experienced a nearly continuous, 20-year surface water connection and had completely coincident water levels. Fill and spill led to minimal convergence in dissolved ions and macroinvertebrate composition, while these constituents converged under fill and merge. The primary factor determining difference in responses was duration of the surface water connection between wetland pairs. Our findings suggest that investigations into the effects of intermittent surface water connections should not consider these connections generically, but need to address the specific types of connections. In particular, fill and spill promotes external water exports while fill and merge favors internal storage. The behaviors of such intermittent connections will likely be accentuated under a future with more frequent and severe climate extremes. Under the Safe and Sustainable Water Resources National Program, work is being done to qu

Soil water content spatial pattern estimated by thermal inertia from air-borne sensors

NASA Astrophysics Data System (ADS)

Coppola, Antonio; Basile, Angelo; Esposito, Marco; Menenti, Massimo; Buonanno, Maurizio

2010-05-01

Remote sensing of soil water content from air- or space-borne platforms offer the possibility to provide large spatial coverage and temporal continuity. The water content can be actually monitored in a thin soil layer, usually up to a depth of 0.05m below the soil surface. To the contrary, difficulties arise in the estimation of the water content storage along the soil profile and its spatial (horizontal) distribution, which are closely connected to soil hydraulic properties and their spatial distribution. A promising approach for estimating soil water contents profiles is the integration of remote sensing of surface water content and hydrological modeling. A major goal of the scientific group is to develop a practical and robust procedure for estimating water contents throughout the soil profile from surface water content. As a first step, in this work, we will show some preliminary results from aircraft images analysis and their validation by field campaigns data. The data extracted from the airborne sensors provided the opportunity of retrieving land surface temperatures with a very high spatial resolution. The surface water content pattern, as deduced by the thermal inertia estimations, was compared to the surface water contents maps measured in situ by time domain reflectometry-based probes.

Fabrication and Wettability Study of WO3 Coated Photocatalytic Membrane for Oil-Water Separation: A Comparative Study with ZnO Coated Membrane.

PubMed

Gondal, Mohammed A; Sadullah, Muhammad S; Qahtan, Talal F; Dastageer, Mohamed A; Baig, Umair; McKinley, Gareth H

2017-05-10

Superhydrophilic and underwater superoleophobic surfaces were fabricated by facile spray coating of nanostructured WO 3 on stainless steel meshes and compared its performance in oil-water separation with ZnO coated meshes. The gravity driven oil-water separation system was designed using these surfaces as the separation media and it was noticed that WO 3 coated stainless steel mesh showed high separation efficiency (99%), with pore size as high as 150 µm, whereas ZnO coated surfaces failed in the process of oil-water separation when the pore exceeded 50 µm size. Since, nanostructured WO 3 is a well known catalyst, the simultaneous photocatalytic degradation of organic pollutants present in the separated water from the oil water separation process were tested using WO 3 coated surfaces under UV radiation and the efficiency of this degradation was found to be quite significant. These results assure that with little improvisation on the oil water separation system, these surfaces can be made multifunctional to work simultaneously for oil-water separation and demineralization of organic pollutants from the separated water. Fabrication of the separating surface, their morphological characteristics, wettability, oil water separation efficiency and photo-catalytic degradation efficiency are enunciated.

A miniature surface tension-driven robot using spatially elliptical moving legs to mimic a water strider's locomotion.

PubMed

Yan, J H; Zhang, X B; Zhao, J; Liu, G F; Cai, H G; Pan, Q M

2015-08-04

The highly agile and efficient water-surface locomotion of the water strider has stimulated substantial interest in biomimetic research. In this paper, we propose a new miniature surface tension-driven robot inspired by the water strider. A key feature of this robot is that its actuating leg possesses an ellipse-like spatial trajectory similar to that of a water strider by using a cam-link mechanism. Simplified models are presented to discuss the leg-water interactions as well as critical conditions for a leg penetrating the water surface, and simulations are performed on the robot's dynamic properties. The final fabricated robot weighs about 3.9 g, and can freely and stably walk on water at different gaits. The maximum forward and turning speeds of the robot are measured as 16 cm s(-1) and 23°/s, respectively. Furthermore, a similarity analysis with Bond number and Weber number demonstrates that the locomotion of this robot is quite analogous to that of a real water strider: the surface tension force dominates the lifting force and plays a major role in the propulsion force. This miniature surface tension-driven robot might have potential applications in many areas such as water quality monitoring and aquatic search and rescue.

Investigation of aluminum surface cleaning using cavitating fluid flow

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ralys, Aurimas; Striška, Vytautas; Mokšin, Vadim

This paper investigates efficiency of specially designed atomizer used to spray water and cavitate microbubbles in water flow. Surface cleaning system was used to clean machined (grinded) aluminum surface from abrasive particles. It is established that cleaning efficiency depends on diameter of the diffuser, water pressure and distance between nozzle and metal surface. It is obtained that the best cleaning efficiency (100%) is achieved at pressure 36 bar, when diameter of diffuser is 0.4 mm and distance between nozzle and surface is 1 mm. It is also established that satisfactory cleaning efficiency (80%) is achieved not only when atomizer ismore » placed closer to metal surface, but also at larger (120 mm) distances.« less

Enthalpic Breakdown of Water Structure on Protein Active-Site Surfaces

PubMed Central

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

2016-01-01

The principles underlying water reorganization around simple non-polar solutes are well understood and provide the framework for classical hydrophobic effect, whereby water molecules structure themselves around solutes so that they maintain favorable energetic contacts with both the solute and with other water molecules. However, for certain solute surface topographies, water molecules, due to their geometry and size, are unable to simultaneously maintain favorable energetic contacts with both the surface and neighboring water molecules. In this study, we analyze the solvation of ligand-binding sites for six structurally diverse proteins using hydration site analysis and measures of local water structure, in order to identify surfaces at which water molecules are unable to structure themselves in a way that maintains favorable enthalpy relative to bulk water. These surfaces are characterized by a high degree of enclosure, weak solute-water interactions, and surface constraints that induce unfavorable pair interactions between neighboring water molecules. Additionally, we find that the solvation of charged side-chains in an active site generally results in favorable enthalpy but can also lead to pair interactions between neighboring water molecules that are significantly unfavorable relative to bulk water. We find that frustrated local structure can occur not only in apolar and weakly polar pockets, where overall enthalpy tends to be unfavorable, but also in charged pockets, where overall water enthalpy tends to be favorable. The characterization of local water structure in these terms may prove useful for evaluating the displacement of water from diverse protein active-site environments. PMID:27169482

40 CFR 257.3-3 - Surface water.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 25 2011-07-01 2011-07-01 false Surface water. 257.3-3 Section 257.3-3... and Practices § 257.3-3 Surface water. (a) For purposes of section 4004(a) of the Act, a facility... Water Act, as amended. (b) For purposes of section 4004(a) of the Act, a facility shall not cause a...

40 CFR 257.3-3 - Surface water.

Code of Federal Regulations, 2010 CFR

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 a...

40 CFR 257.3-3 - Surface water.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 26 2012-07-01 2011-07-01 true Surface water. 257.3-3 Section 257.3-3... and Practices § 257.3-3 Surface water. (a) For purposes of section 4004(a) of the Act, a facility... Water Act, as amended. (b) For purposes of section 4004(a) of the Act, a facility shall not cause a...

40 CFR 257.3-3 - Surface water.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 25 2014-07-01 2014-07-01 false Surface water. 257.3-3 Section 257.3-3... and Practices § 257.3-3 Surface water. (a) For purposes of section 4004(a) of the Act, a facility... Water Act, as amended. (b) For purposes of section 4004(a) of the Act, a facility shall not cause a...

40 CFR 257.3-3 - Surface water.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 26 2013-07-01 2013-07-01 false Surface water. 257.3-3 Section 257.3-3... and Practices § 257.3-3 Surface water. (a) For purposes of section 4004(a) of the Act, a facility... Water Act, as amended. (b) For purposes of section 4004(a) of the Act, a facility shall not cause a...

Delay in the Freezing of Supercooled Water Drops on Superhydrophobic Surfaces of Silicone Rubber at Negative Temperatures

NASA Astrophysics Data System (ADS)

Bezdomnikov, A. A.; Emel'yanenko, A. M.; Emel'yanenko, K. A.; Boinovich, L. B.

2018-01-01

A method is proposed for fabricating textured superhydrophobic surfaces of silicone rubber with mechanical resistance toward liquid or freezing aqueous solutions. The anti-icing characteristics of silicone rubber samples that differ in the wetting characteristics and mechanical stability of their micro- and nanotextures are derived by analyzing the delays in the freezing of supercooled sessile water drops deposited on the sample surface. The longest delay in freezings are observed for sessile water drops on superhydrophobic surfaces prepared by laser texturing with subsequent application of a layer of a hydrophobic agent to consolidate the textural elements. Delay in freezings can be as long as tens of hours on such surfaces at T = -18°C. The prepared superhydrophobic surfaces exhibit greater anti-icing ability with respect to aqueous salt solutions than to deionized water.

Enhanced load-carrying capacity of hairy surfaces floating on water.

PubMed

Xue, Yahui; Yuan, Huijing; Su, Weidong; Shi, Yipeng; Duan, Huiling

2014-05-08

Water repellency of hairy surfaces depends on the geometric arrangement of these hairs and enables different applications in both nature and engineering. We investigate the mechanism and optimization of a hairy surface floating on water to obtain its maximum load-carrying capacity by the free energy and force analyses. It is demonstrated that there is an optimum cylinder spacing, as a result of the compromise between the vertical capillary force and the gravity, so that the hairy surface has both high load-carrying capacity and mechanical stability. Our analysis makes it clear that the setae on water striders' legs or some insects' wings are in such an optimized geometry. Moreover, it is shown that surface hydrophobicity can further increase the capacity of a hairy surface with thick cylinders, while the influence is negligible when the cylinders are thin.

Enhanced load-carrying capacity of hairy surfaces floating on water

PubMed Central

Xue, Yahui; Yuan, Huijing; Su, Weidong; Shi, Yipeng; Duan, Huiling

2014-01-01

Water repellency of hairy surfaces depends on the geometric arrangement of these hairs and enables different applications in both nature and engineering. We investigate the mechanism and optimization of a hairy surface floating on water to obtain its maximum load-carrying capacity by the free energy and force analyses. It is demonstrated that there is an optimum cylinder spacing, as a result of the compromise between the vertical capillary force and the gravity, so that the hairy surface has both high load-carrying capacity and mechanical stability. Our analysis makes it clear that the setae on water striders' legs or some insects' wings are in such an optimized geometry. Moreover, it is shown that surface hydrophobicity can further increase the capacity of a hairy surface with thick cylinders, while the influence is negligible when the cylinders are thin. PMID:24808757

On the Role of Fe2O3 Surface States for Water Splitting

NASA Astrophysics Data System (ADS)

Caspary Toroker, Maytal

Understanding the chemical nature and role of electrode surface states is crucial for improved electrochemical cell operation. For iron (III) oxide (α-Fe2O3) , which is one of the most widely studied anode electrodes used for water splitting, surface states were related to the appearance of a dominant absorption peak during water splitting. The chemical origin of this signature is still unclear and this open question has provoked tremendous debate. In order to pin down the origin and role of surface states, we perform first principle calculations with density functional theory +U on several possible adsorbates at the α-Fe2O3(0001) surface. We show that the origin of the surface absorption peak could be a Fe-Otype bond that functions as an essential intermediate of water oxidation

Communication: Contrasting effects of glycerol and DMSO on lipid membrane surface hydration dynamics and forces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schrader, Alex M.; Cheng, Chi-Yuan; Israelachvili, Jacob N.

2016-07-28

Glycerol and dimethyl sulfoxide (DMSO) are commonly used cryoprotectants in cellular systems, but due to the challenges of measuring the properties of surface-bound solvent, fundamental questions remain regarding the concentration, interactions, and conformation of these solutes at lipid membrane surfaces. We measured the surface water diffusivity at gel-phase dipalmitoylphosphatidylcholine (DPPC) bilayer surfaces in aqueous solutions containing ≤7.5 mol. % of DMSO or glycerol using Overhauser dynamic nuclear polarization. We found that glycerol similarly affects the diffusivity of water near the bilayer surface and that in the bulk solution (within 20%), while DMSO substantially increases the diffusivity of surface water relativemore » to bulk water. We compare these measurements of water dynamics with those of equilibrium forces between DPPC bilayers in the same solvent mixtures. DMSO greatly decreases the range and magnitude of the repulsive forces between the bilayers, whereas glycerol increases it. We propose that the differences in hydrogen bonding capability of the two solutes leads DMSO to dehydrate the lipid head groups, while glycerol affects surface hydration only as much as it affects the bulk water properties. The results suggest that the mechanism of the two most common cryoprotectants must be fundamentally different: in the case of DMSO by decoupling the solvent from the lipid surface, and in the case of glycerol by altering the hydrogen bond structure and intermolecular cohesion of the global solvent, as manifested by increased solvent viscosity.« less

Trends in water monomer adsorption and dissociation on flat insulating surfaces.

PubMed

Hu, Xiao Liang; Carrasco, Javier; Klimeš, Jiří; Michaelides, Angelos

2011-07-21

The interaction of water with solid surfaces is key to a wide variety of industrial and natural processes. However, the basic principles that dictate how stable and in which state (intact or dissociated) water will be on a given surface are not fully understood. Towards this end, we have used density functional theory to examine water monomer adsorption on the (001) surfaces of a broad range of alkaline earth oxides, alkaline earth sulfides, alkali fluorides, and alkali chlorides. Some interesting general conclusions are arrived at: (i) on all the surfaces considered only a few specific adsorption structures are favoured; (ii) water becomes more stable upon descending the oxide and fluoride series but does not vary much upon going down the chloride and sulfide series; (iii) water is stabilised both by an increase in the lattice constant, which facilitates hydrogen bonding to the substrate, and by the flexibility of the substrate. These are also factors that favour water dissociation. We hope that this study is of some value in better understanding the surface science of water in general, and in assisting in the interpretation and design of future experiments. This journal is © the Owner Societies 2011

Reimagining cost recovery in Pakistan's irrigation system through willingness-to-pay estimates for irrigation water from a discrete choice experiment

NASA Astrophysics Data System (ADS)

Bell, Andrew Reid; Shah, M. Azeem Ali; Ward, Patrick S.

2014-08-01

It is widely argued that farmers are unwilling to pay adequate fees for surface water irrigation to recover the costs associated with maintenance and improvement of delivery systems. In this paper, we use a discrete choice experiment to study farmer preferences for irrigation characteristics along two branch canals in Punjab Province in eastern Pakistan. We find that farmers are generally willing to pay well in excess of current surface water irrigation costs for increased surface water reliability and that the amount that farmers are willing to pay is an increasing function of their existing surface water supply as well as location along the main canal branch. This explicit translation of implicit willingness-to-pay (WTP) for water (via expenditure on groundwater pumping) to WTP for reliable surface water demonstrates the potential for greatly enhanced cost recovery in the Indus Basin Irrigation System via appropriate setting of water user fees, driven by the higher WTP of those currently receiving reliable supplies.

Reimagining cost recovery in Pakistan's irrigation system through willingness-to-pay estimates for irrigation water from a discrete choice experiment

PubMed Central

Bell, Andrew Reid; Shah, M Azeem Ali; Ward, Patrick S

2014-01-01

It is widely argued that farmers are unwilling to pay adequate fees for surface water irrigation to recover the costs associated with maintenance and improvement of delivery systems. In this paper, we use a discrete choice experiment to study farmer preferences for irrigation characteristics along two branch canals in Punjab Province in eastern Pakistan. We find that farmers are generally willing to pay well in excess of current surface water irrigation costs for increased surface water reliability and that the amount that farmers are willing to pay is an increasing function of their existing surface water supply as well as location along the main canal branch. This explicit translation of implicit willingness-to-pay (WTP) for water (via expenditure on groundwater pumping) to WTP for reliable surface water demonstrates the potential for greatly enhanced cost recovery in the Indus Basin Irrigation System via appropriate setting of water user fees, driven by the higher WTP of those currently receiving reliable supplies. PMID:25552779

Filamentary superhydrophobic Teflon surfaces: Moderate apparent contact angle but superior air-retaining properties.

PubMed

Di Mundo, Rosa; Bottiglione, Francesco; Palumbo, Fabio; Notarnicola, Michele; Carbone, Giuseppe

2016-11-15

Micro-scale textured Teflon surfaces, resulting from plasma etching modification, show extremely high water contact angle values and fairly good resistance to water penetration when hit by water drops at medium-high speed. This behavior is more pronounced when these surfaces present denser and smaller micrometric reliefs. Tailoring the top of these reliefs with a structure which further stabilizes the air may further increase resistance to wetting (water penetration) under static and dynamic conditions. Conditions of the oxygen fed plasma were tuned in order to explore the possibility of obtaining differently topped structures on the surface of the polymer. Scanning Electron Microscopy (SEM) was used to explore topography and X-ray Photoelectron Spectroscopy (XPS) to assess chemical similarity of the modified surfaces. Beside the usual advancing and receding water contact angle (WCA) measurements, surfaces were subjected to high speed impacting drops and immersion in water. At milder, i.e. shorter time and lower input power, plasma conditions formation of peculiar filaments is observed on the top of the sculpted reliefs. Filamentary topped surfaces result in a lower WCA than the spherical ones, appearing in this sense less superhydrophobic. However, these surfaces give rise to the formation of a more pronounced air layer when placed underwater. Further, when hit by water drops falling at medium/high speed, they show a higher resistance to water penetration and a sensitively lower surface-liquid contact time. The contact time is as low as previously observed only on heated solids. This behavior may be ascribed to the cavities formed beneath the filaments which, similarly with the salvinia leaf structures, require a surplus of pressure to be filled by water. Also, it suggests a different concept of superhydrophobicity, which cannot be expected on the basis of the conventional water contact angle characterization. Copyright © 2016 Elsevier Inc. All rights reserved.

The Surface Water and Ocean Topography Satellite Mission - An Assessment of Swath Altimetry Measurements of River Hydrodynamics

NASA Technical Reports Server (NTRS)

Wilson, Matthew D.; Durand, Michael; Alsdorf, Douglas; Chul-Jung, Hahn; Andreadis, Konstantinos M.; Lee, Hyongki

2012-01-01

The Surface Water and Ocean Topography (SWOT) satellite mission, scheduled for launch in 2020 with development commencing in 2015, will provide a step-change improvement in the measurement of terrestrial surface water storage and dynamics. In particular, it will provide the first, routine two-dimensional measurements of water surface elevations, which will allow for the estimation of river and floodplain flows via the water surface slope. In this paper, we characterize the measurements which may be obtained from SWOT and illustrate how they may be used to derive estimates of river discharge. In particular, we show (i) the spatia-temporal sampling scheme of SWOT, (ii) the errors which maybe expected in swath altimetry measurements of the terrestrial surface water, and (iii) the impacts such errors may have on estimates of water surface slope and river discharge, We illustrate this through a "virtual mission" study for a approximately 300 km reach of the central Amazon river, using a hydraulic model to provide water surface elevations according to the SWOT spatia-temporal sampling scheme (orbit with 78 degree inclination, 22 day repeat and 140 km swath width) to which errors were added based on a two-dimension height error spectrum derived from the SWOT design requirements. Water surface elevation measurements for the Amazon mainstem as may be observed by SWOT were thereby obtained. Using these measurements, estimates of river slope and discharge were derived and compared to those which may be obtained without error, and those obtained directly from the hydraulic model. It was found that discharge can be reproduced highly accurately from the water height, without knowledge of the detailed channel bathymetry using a modified Manning's equation, if friction, depth, width and slope are known. Increasing reach length was found to be an effective method to reduce systematic height error in SWOT measurements.

Water and Ethanol Droplet Wetting Transition during Evaporation on Omniphobic Surfaces

PubMed Central

Chen, Xuemei; Weibel, Justin A.; Garimella, Suresh V.

2015-01-01

Omniphobic surfaces with reentrant microstructures have been investigated for a range of applications, but the evaporation of high- and low-surface-tension liquid droplets placed on such surfaces has not been rigorously studied. In this work, we develop a technique to fabricate omniphobic surfaces on copper substrates to allow for a systematic examination of the effects of surface topography on the evaporation dynamics of water and ethanol droplets. Compared to a water droplet, the ethanol droplet not only evaporates faster, but also inhibits Cassie-to-Wenzel wetting transitions on surfaces with certain geometries. We use an interfacial energy-based description of the system, including the transition energy barrier and triple line energy, to explain the underlying transition mechanism and behaviour observed. Suppression of the wetting transition during evaporation of droplets provides an important metric for evaluating the robustness of omniphobic surfaces requiring such functionality. PMID:26603940

Simulation of ground-water flow, surface-water flow, and a deep sewer tunnel system in the Menomonee Valley, Milwaukee, Wisconsin

USGS Publications Warehouse

Dunning, C.P.; Feinstein, D.T.; Hunt, R.J.; Krohelski, J.T.

2004-01-01

Numerical models were constructed for simulation of ground-water flow in the Menomonee Valley Brownfield, in Milwaukee, Wisconsin. An understanding of ground-water flow is necessary to develop an efficient program to sample ground water for contaminants. Models were constructed in a stepwise fashion, beginning with a regional, single-layer, analytic-element model (GFLOW code) that provided boundary conditions for a local, eight layer, finite-difference model (MODFLOW code) centered on the Menomonee Valley Brownfield. The primary source of ground water to the models is recharge over the model domains; primary sinks for ground water within the models are surface-water features and the Milwaukee Metropolitan Sewerage District Inline Storage System (ISS). Calibration targets were hydraulic heads, surface-water fluxes, vertical gradients, and ground-water infiltration to the ISS. Simulation of ground-water flow by use of the MODFLOW model indicates that about 73 percent of recharge within the MODFLOW domain circulates to the ISS and 27 percent discharges to gaining surface-water bodies. In addition, infiltration to the ISS comes from the following sources: 36 percent from recharge within the model domain, 45 percent from lateral flow into the domain, 15 percent from Lake Michigan, and 4 percent from other surface-water bodies. Particle tracking reveals that the median traveltime from the recharge point to surface-water features is 8 years; the median time to the ISS is 255 years. The traveltimes to the ISS are least over the northern part of the valley, where dolomite is near the land surface. The distribution of traveltimes in the MODFLOW simulation is greatly influenced by the effective porosity values assigned to the various lithologies.

Monitoring the dynamics of surface water fraction from MODIS time series in a Mediterranean environment

NASA Astrophysics Data System (ADS)

Li, Linlin; Vrieling, Anton; Skidmore, Andrew; Wang, Tiejun; Turak, Eren

2018-04-01

Detailed spatial information of changes in surface water extent is needed for water management and biodiversity conservation, particularly in drier parts of the globe where small, temporally-variant wetlands prevail. Although global surface water histories are now generated from 30 m Landsat data, for many locations they contain large temporal gaps particularly for longer periods (>10 years) due to revisit intervals and cloud cover. Daily Moderate Resolution Imaging Spectrometer (MODIS) imagery has potential to fill such gaps, but its relatively coarse spatial resolution may not detect small water bodies, which can be of great ecological importance. To address this problem, this study proposes and tests options for estimating the surface water fraction from MODIS 16-day 500 m Bidirectional Reflectance Distribution Function (BRDF) corrected surface reflectance image composites. The spatial extent of two Landsat tiles over Spain were selected as test areas. We obtained a 500 m reference dataset on surface water fraction by spatially aggregating 30 m binary water masks obtained from the Landsat-derived C-version of Function of Mask (CFmask), which themselves were evaluated against high-resolution Google Earth imagery. Twelve regression tree models were developed with two approaches, Random Forest and Cubist, using spectral metrics derived from MODIS data and topographic parameters generated from a 30 m spatial resolution digital elevation model. Results showed that accuracies were higher when we included annual summary statistics of the spectral metrics as predictor variables. Models trained on a single Landsat tile were ineffective in mapping surface water in the other tile, but global models trained with environmental conditions from both tiles can provide accurate results for both study areas. We achieved the highest accuracy with Cubist global model (R2 = 0.91, RMSE = 11.05%, MAE = 7.67%). Our method was not only effective for mapping permanent water fraction, but also in accurately capturing temporal fluctuations of surface water. Based on this good performance, we produced surface water fraction maps at 16-day interval for the 2000-2015 MODIS archive. Our approach is promising for monitoring surface water fraction at high frequency time intervals over much larger regions provided that training data are collected across the spatial domain for which the model will be applied.

Aerobic methane production in surface waters of the Gulf of Mexico

NASA Astrophysics Data System (ADS)

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

2011-12-01

Near surface water of the global oceans often show elevated methane concentrations compared to the water column below with concentrations in supersaturation in regard to the atmosphere (Lamontagne et al. 1973), resulting in a source of this potent greenhouse gas to the atmosphere. The mechanisms leading to methane supersaturation in surface waters remains unclear. Incubations with Trichodesmium-containing Pacific surface water suggested methylphosphonate as potential methane precursor under phosphate limiting conditions (Karl et al. 2008), whereas in phosphate rich Arctic surface waters, DMSP addition stimulated methane production (Damm et al. 2010). Surface waters of the Gulf of Mexico typically exhibit a methane maximum that is conincident with the deep chlorophyll maximum, below the depths where Trichodesmium is abundant. Addition of methylphosphonate, dimethylsulfoniopropionate (DMSP) or methane thiol (MeSH), the proposed methane precursor in DMSP conversion to methane, to oxic sea water did not affect methane production within the chlorophyll maximum at most stations, whereas methyl phosphonate addition stimulated methane production in the surface water and proposed deep Trichodesmium horizon. Pre-filtration of the water through a 10 μm sieve, which eliminated Trichodesmium, or through a 1.2 μm filter, which eliminated additional cyanobacteria such as Synechococcus, did not reduce methane production. Under dark oxic and dark anoxic conditions, however, methane production was reduced 5 and 7-20 fold, respectively, indicating that anerobic methane production in anoxic microniches is not responsible for the methane production. The reduction of methane production under dark conditions suggests that methane production is, in some yet unrecognized way, linked to phototrophic metabolism. Cyanobacteria are likely not responsible for the observed aerobic methane production in the surface waters of the Gulf of Mexico and while methylphosphonate is a potential precursor in the surface waters, the precursor and methanism of methane production within the coincident deep chlorophyll/methane maximum remains unknown. Lamontagne R, Swinnert J, Linnenbo V, Smith WD (1973) Methane concentrations in various marine environments. Journal of Geophysical Research 78, 5317-5324 Karl DM et al. (2008) Aerobic production of methane in the sea. Nature Geosciences 1, 473-478 Damm E et al. (2010) Methane production in aerobic oligotrophic surface water in the central Arctic Ocean. Biogeosciences 7, 1099-1108

Distribution of acidic and neutral drugs in surface waters near sewage treatment plants in the lower Great Lakes, Canada.

PubMed

Metcalfe, Chris D; Miao, Xiu-Sheng; Koenig, Brenda G; Struger, John

2003-12-01

Prescription and nonprescription drugs have been detected in rivers and streams in Europe and the United States. Sewage treatment plants (STPs) are an important source of these contaminants, but few data exist on the spatial distribution of drugs in surface waters near STPs. Samples of surface water were collected in the summer and fall of 2000 at open-water sites in the lower Great Lakes (Lake Ontario and Lake Erie), at sites near the two STPs for the city of Windsor (ON, Canada), and at sites in Hamilton Harbour (ON, Canada), an embayment of western Lake Ontario that receives discharges from several STPs. In a follow-up study in the summer of 2002, samples of surface water and final effluent from adjacent STPs were collected from sites in Hamilton Harbour and Windsor. In addition, surface water and STP effluent samples were collected in Peterborough (ON, Canada). All samples of surface water and STP effluents were analyzed for selected acidic and neutral drugs. In the survey of Hamilton Harbour and Windsor conducted in 2000, acidic drugs and the antiepileptic drug carbamazepine were detected at ng/L concentrations at sites that were up to 500 m away from the STP, but the hydrological conditions of the receiving waters strongly influenced the spatial distribution of these compounds. Drugs were not detected at open-water locations in western Lake Erie or in the Niagara River near the municipality of Niagara-on-the-Lake (ON, Canada). However, clofibric acid, ketoprofen, fenoprofen, and carbamazepine were detected in samples collected in the summer of 2000 at sites in Lake Ontario and at a site in the Niagara River (Fort Erie, ON, Canada) that were relatively remote from STP discharges. Follow-up studies in the summer of 2002 indicated that concentrations of acidic and neutral drugs in surface waters near the point of sewage discharge into the Little River (ON, Canada) STP were approximately equal to the concentrations in the final effluent from the STP. Caffeine and cotinine, a metabolite of nicotine, were generally present in STP effluents and surface waters contaminated by drugs. The antidepressant fluoxetine and the antibiotic trimethoprom were also detected in most STP effluents and some surface water samples. For the first time, the lipid regulating drug atorvastatin was detected in samples of STP effluent and surface water.

Per- and Polyfluoroalkyl Substances in Swedish Groundwater and Surface Water: Implications for Environmental Quality Standards and Drinking Water Guidelines.

PubMed

Gobelius, Laura; Hedlund, Johanna; Dürig, Wiebke; Tröger, Rikard; Lilja, Karl; Wiberg, Karin; Ahrens, Lutz

2018-04-03

The aim of this study was to assess per- and polyfluoroalkyl substances (PFASs) in the Swedish aquatic environment, identify emission sources, and compare measured concentrations with environmental quality standards (EQS) and (drinking) water guideline values. In total, 493 samples were analyzed in 2015 for 26 PFASs (∑ 26 PFASs) in surface water, groundwater, landfill leachate, sewage treatment plant effluents and reference lakes, focusing on hot spots and drinking water sources. Highest ∑ 26 PFAS concentrations were detected in surface water (13 000 ng L -1 ) and groundwater (6400 ng L -1 ). The dominating fraction of PFASs in surface water were perfluoroalkyl carboxylates (PFCAs; 64% of ∑ 26 PFASs), with high contributions from C 4 -C 8 PFCAs (94% of ∑PFCAs), indicating high mobility of shorter chain PFCAs. In inland surface water, the annual average (AA)-EQS of the EU Water Framework Directive of 0.65 ng L -1 for ∑PFOS (linear and branched isomers) was exceeded in 46% of the samples. The drinking water guideline value of 90 ng L -1 for ∑ 11 PFASs recommended by the Swedish EPA was exceeded in 3% of the water samples from drinking water sources ( n = 169). The branched isomers had a noticeable fraction in surface- and groundwater for perfluorooctanesulfonamide, perfluorohexanesulfonate, and perfluorooctanesulfonate, highlighting the need to include branched isomers in future guidelines.

Surface water storage capacity of twenty tree species in Davis, California

Treesearch

Qingfu Xiao; E. Gregory McPherson

2016-01-01

Urban forestry is an important green infrastructure strategy because healthy trees can intercept rainfall, reducing stormwater runoff and pollutant loading. Surface saturation storage capacity, defined as the thin film of water that must wet tree surfaces before flow begins, is the most important variable influencing rainfall interception processes. Surface storage...

Heterogeneous nucleation of ice on carbon surfaces.

PubMed

Lupi, Laura; Hudait, Arpa; Molinero, Valeria

2014-02-26

Atmospheric aerosols can promote the heterogeneous nucleation of ice, impacting the radiative properties of clouds and Earth's climate. The experimental investigation of heterogeneous freezing of water droplets by carbonaceous particles reveals widespread ice freezing temperatures. It is not known which structural and chemical characteristics of soot account for the variability in ice nucleation efficiency. Here we use molecular dynamics simulations to investigate the nucleation of ice from liquid water in contact with graphitic surfaces. We find that atomically flat carbon surfaces promote heterogeneous nucleation of ice, while molecularly rough surfaces with the same hydrophobicity do not. Graphitic surfaces and other surfaces that promote ice nucleation induce layering in the interfacial water, suggesting that the order imposed by the surface on liquid water may play an important role in the heterogeneous nucleation mechanism. We investigate a large set of graphitic surfaces of various dimensions and radii of curvature and find that variations in nanostructures alone could account for the spread in the freezing temperatures of ice on soot in experiments. We conclude that a characterization of the nanostructure of soot is needed to predict its ice nucleation efficiency.

Inventory of File sref_em.t03z.pgrb221.p1.f06.grib2

Science.gov Websites

surface WEASD 6 hour fcst Water Equivalent of Accumulated Snow Depth [kg/m^2] 016 surface APCP 0-6 hour surface WEASD 0-6 hour acc Water Equivalent of Accumulated Snow Depth [kg/m^2] 019 surface CSNOW 6 hour hour fcst Specific Humidity [kg/kg] 401 surface NCPCP 0-6 hour acc Large-Scale Precipitation (non

Surface waves generated by shallow underwater explosions

NASA Technical Reports Server (NTRS)

Falade, A.; Holt, M.

1978-01-01

Surface water waves generated by surface and near surface point explosions are calculated. Taking the impulse distribution imparted at the water surface by the explosion as the overriding mechanism for transferring energy of the explosive to surface wave motion, the linearized theory of Kranzer and Keller is used to obtain the wave displacement in the far field. The impulse distribution is obtained by integrating the pressure wave over an appropriate time interval on a horizontal surface just beneath the undisturbed water surface. For surface explosions, a modified form of the similarity method first used by Collins and Holt is used to obtain the flow field. In the case of submerged explosions, the flow field is estimated by making necessary modifications to Sedov's similarity solution to account for the venting that accompanies the interaction of the leading (blast) wave with the ocean surface. Surface waves generated by a charge at six depths of placement (0.15 m, 0.30 m, 0.61 m, 0.91 m, 1.37 m, 3.05 m) are considered in addition to surface explosions. The results seem to support the existence of an upper critical depth phenomenon (of the type already established for chemical explosions) for point (nuclear) explosions.

DFT simulations of water adsorption and activation on low-index α-Ga2O3 surfaces.

PubMed

Zhou, Xin; Hensen, Emiel J M; van Santen, Rutger A; Li, Can

2014-06-02

Density functional theory (DFT) calculations are used to explore water adsorption and activation on different α-Ga2O3 surfaces, namely (001), (100), (110), and (012). The geometries and binding energies of molecular and dissociative adsorption are studied as a function of coverage. The simulations reveal that dissociative water adsorption on all the studied low-index surfaces are thermodynamically favorable. Analysis of surface energies suggests that the most preferentially exposed surface is (012). The contribution of surface relaxation to the respective surface energies is significant. Calculations of electron local density of states indicate that the electron-energy band gaps for the four investigated surfaces appears to be less related to the difference in coordinative unsaturation of the surface atoms, but rather to changes in the ionicity of the surface chemical bonds. The electrochemical computation is used to investigate the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) on α-Ga2O3 surfaces. Our results indicate that the (100) and (110) surfaces, which have low stability, are the most favorable ones for HER and OER, respectively. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Marangoni flow in an evaporating water droplet

NASA Astrophysics Data System (ADS)

Xu, Xuefeng; Luo, Jianbin

2007-09-01

Marangoni effect has been observed in many liquids, but its existence in pure water is still a debated problem. In the present work, the Marangoni flow in evaporating water droplets has been observed by using fluorescent nanoparticles. Flow patterns indicate that a stagnation point where the surface flow, the surface tension gradient, and the surface temperature gradient change their directions exists at the droplet surface. The deduced nonmonotonic variation of the droplet surface temperature, which is different from that in some previous works, is explained by a heat transfer model considering the adsorbed thin film of the evaporating liquid droplet.

Super-hydrophobicity fundamentals: implications to biofouling prevention.

PubMed

Marmur, Abraham

2006-01-01

The theory of wetting on super-hydrophobic surfaces is presented and discussed, within the general framework of equilibrium wetting and contact angles. Emphasis is put on the implications of super-hydrophobicity to the prevention of biofouling. Two main lines of thought are discussed, viz. i) "mirror imaging" of the Lotus effect, namely designing a surface that repels biological entities by being super-hydrophilic, and ii) designing a surface that minimises the water-wetted area when submerged in water (by keeping an air film between the water and the surface), so that the suspended biological entities have a low probability of encountering the solid surface.

[ASSESSMENT OF POTENTIAL RISK FOR CONTAMINATION OF SURFACE WATER RESERVOIRS BY PATHOGENS OF HUMAN PARASITIC DISEASES].

PubMed

Khromenkova, E P; Dimidova, L L; Dumbadze, O S; Aidinov, G T; Shendo, G L; Agirov, A Kh; Batchaev, Kh Kh

2015-01-01

Sanitary and parasitological studies of the waste effluents and surface reservoir waters were conducted in the south of Russia. The efficiency of purification of waste effluents from the pathogens of parasitic diseases was investigated in the region's sewage-purification facilities. The water of the surface water reservoirs was found to contain helminthic eggs and larvae and intestinal protozoan cysts because of the poor purification and disinfection of service fecal sewage waters. The poor purification and disinvasion of waste effluents in the region determine the potential risk of contamination of the surface water reservoirs and infection of the population with the pathogens of human parasitic diseases.

Photoionization of environmentally polluting aromatic chlorides and nitrides on the water surface by laser and synchrotron radiations.

PubMed

Sato, Miki; Maeda, Yuki; Ishioka, Toshio; Harata, Akira

2017-11-20

The detection limits and photoionization thresholds of polycyclic aromatic hydrocarbons and their chlorides and nitrides on the water surface are examined using laser two-photon ionization and single-photon ionization, respectively. The laser two-photon ionization methods are highly surface-selective, with a high sensitivity for aromatic hydrocarbons tending to accumulate on the water surface in the natural environment due to their highly hydrophobic nature. The dependence of the detection limits of target aromatic molecules on their physicochemical properties (photoionization thresholds relating to excess energy, molar absorptivity, and the octanol-water partition coefficient) is discussed. The detection limit clearly depends on the product of the octanol-water partition coefficient and molar absorptivity, and no clear dependence was found on excess energy. The detection limits of laser two-photon ionization for these types of molecules on the water surface are formulated.

Water adsorption on the Fe3O4(111) surface: dissociation and network formation.

PubMed

Zaki, Eman; Mirabella, Francesca; Ivars-Barceló, Francisco; Seifert, Jan; Carey, Spencer; Shaikhutdinov, Shamil; Freund, Hans-Joachim; Li, Xiaoke; Paier, Joachim; Sauer, Joachim

2018-06-13

We monitored adsorption of water on a well-defined Fe3O4(111) film surface at different temperatures as a function of coverage using infrared reflection-absorption spectroscopy, temperature programmed desorption, and single crystal adsorption calorimetry. Additionally, density functional theory was employed using a Fe3O4(111)-(2 × 2) slab model to generate 15 energy minimum structures for various coverages. Corresponding vibrational properties of the adsorbed water species were also computed. The results show that water molecules readily dissociate on regular surface Fetet1-O ion pairs to form "monomers", i.e., terminal Fe-OH and surface OH groups. Further water molecules adsorb on the hydroxyl covered surface non-dissociatively and form "dimers" and larger oligomers, which ultimately assemble into an ordered (2 × 2) hydrogen-bonded network structure with increasing coverage prior to the formation of a solid water film.

Compatibility Study of Silver Biocide in Drinking Water with Candidate Metals for Crew Exploration Vehicle Potable Water System

NASA Technical Reports Server (NTRS)

Adam, Niklas M.

2009-01-01

The stability of silver biocide, used to keep drinking water on the CEV potable water sterile, is unknown as the system design is still in progress. Silver biocide in water can deplete rapidly when exposed to various metal surfaces. Additionally, silver depletion rates may be affected by the surface-area-to-volume (SA/V) ratios in the water system. Therefore, to facilitate the CEV water system design, it would be advantageous to know the biocide depletion rates in water exposed to the surfaces of these candidate metals at various SA/V ratios. Certain surface treatments can be employed to reduce the depletion rates of silver compared to the base metal. The purpose of this work is to determine the compatibility of specific spaceflight-certified metals that could used in the design of the CEV potable water system with silver biocide as well as understand the effect of surface are to volume ratios of metals used in the construction of the potable water system on the silver concentration.

Mycobacteria in water used for personal hygiene in heavy industry and collieries: a potential risk for employees.

PubMed

Ulmann, Vit; Kracalikova, Anna; Dziedzinska, Radka

2015-03-04

Environmental mycobacteria (EM) constitute a health risk, particularly for immunocompromised people. Workers in heavy industry and in collieries represent an at-risk group of people as their immunity is often weakened by long-term employment in dusty environments, frequent smoking and an increased occurrence of pulmonary diseases. This study was concerned with the presence of EM in non-drinking water used for the hygiene of employees in six large industrial companies and collieries. Over a period of ten years, 1096 samples of surface water treated for hygiene purposes (treated surface water) and treated surface water diluted with mining water were examined. EM were detected in 63.4 and 41.5% samples of treated surface water and treated surface water diluted with mining water, respectively. Mycobacterium gordonae, M. avium-intracellulare and M. kansasii were the most frequently detected species. Adoption of suitable precautions should be enforced to reduce the incidence of mycobacteria in shower water and to decrease the infectious pressure on employees belonging to an at-risk group of people.

Distribution of icy particles across Enceladus' surface as derived from Cassini-VIMS measurements

USGS Publications Warehouse

Jaumann, R.; Stephan, K.; Hansen, G.B.; Clark, R.N.; Buratti, B.J.; Brown, R.H.; Baines, K.H.; Newman, S.F.; Bellucci, G.; Filacchione, G.; Coradini, A.; Cruikshank, D.P.; Griffith, C.A.; Hibbitts, C.A.; McCord, T.B.; Nelson, R.M.; Nicholson, P.D.; Sotin, Christophe; Wagner, R.

2008-01-01

The surface of Enceladus consists almost completely of water ice. As the band depths of water ice absorptions are sensitive to the size of particles, absorptions can be used to map variations of icy particles across the surface. The Visual and Infrared Mapping Spectrometer (VIMS) observed Enceladus with a high spatial resolution during three Cassini flybys in 2005 (orbits EN 003, EN 004 and EN 011). Based on these data we measured the band depths of water ice absorptions at 1.04, 1.25, 1.5, and 2 ??m. These band depths were compared to water ice models that represent theoretically calculated reflectance spectra for a range of particle diameters between 2 ??m and 1 mm. The agreement between the experimental (VIMS) and model values supports the assumption that pure water ice characterizes the surface of Enceladus and therefore that variations in band depth correspond to variations in water ice particle diameters. Our measurements show that the particle diameter of water ice increases toward younger tectonically altered surface units with the largest particles exposed in relatively "fresh" surface material. The smallest particles were generally found in old densely cratered terrains. The largest particles (???0.2 mm) are concentrated in the so called "tiger stripes" at the south pole. In general, the particle diameters are strongly correlated with geologic features and surface ages, indicating a stratigraphic evolution of the surface that is caused by cryovolcanic resurfacing and impact gardening. ?? 2007 Elsevier Inc. All rights reserved.

Assessing the influence of climate change and inter-basin water diversion on Haihe River basin, eastern China: a coupled model approach

NASA Astrophysics Data System (ADS)

Xia, Jun; Wang, Qiang; Zhang, Xiang; Wang, Rui; She, Dunxian

2018-04-01

The modeling of changes in surface water and groundwater in the areas of inter-basin water diversion projects is quite difficult because surface water and groundwater models are run separately most of the time and the lack of sufficient data limits the application of complex surface-water/groundwater coupling models based on physical laws, especially for developing countries. In this study, a distributed surface-water and groundwater coupling model, named the distributed time variant gain model-groundwater model (DTVGM-GWM), was used to assess the influence of climate change and inter-basin water diversion on a watershed hydrological cycle. The DTVGM-GWM model can reflect the interaction processes of surface water and groundwater at basin scale. The model was applied to the Haihe River Basin (HRB) in eastern China. The possible influences of climate change and the South-to-North Water Diversion Project (SNWDP) on surface water and groundwater in the HRB were analyzed under various scenarios. The results showed that the newly constructed model DTVGM-GWM can reasonably simulate the surface and river runoff, and describe the spatiotemporal distribution characteristics of groundwater level, groundwater storage and phreatic recharge. The prediction results under different scenarios showed a decline in annual groundwater exploitation and also runoff in the HRB, while an increase of groundwater storage and groundwater level after the SNWDP's operation. Additionally, as the project also addresses future scenarios, a slight increase is predicted in the actual evapotranspiration, soil water content and phreatic recharge. This study provides valuable insights for developing sustainable groundwater management options for the HRB.

Spatial distribution of perchlorate, iodide and thiocyanate in the aquatic environment of Tianjin, China: environmental source analysis.

PubMed

Qin, Xiaolei; Zhang, Tao; Gan, Zhiwei; Sun, Hongwen

2014-09-01

Although China is the largest producer of fireworks (perchlorate-containing products) in the world, the pathways through which perchlorate enters the environment have not been characterized completely in this country. In this study, perchlorate, iodide and thiocyanate were measured in 101 water samples, including waste water, surface water, sea water and paired samples of rain water and surface runoff collected in Tianjin, China. The concentrations of the target anions were generally on the order of rain>surface water≈waste water treatment plant (WWTP) influent>WWTP effluent. High concentrations of perchlorate, iodide and thiocyanate were detected in rain samples, ranging from 0.35 to 27.3 (median: 4.05), 0.51 to 8.33 (2.92), and 1.31 to 107 (5.62) ngmL(-)(1), respectively. Furthermore, the concentrations of the target anions in rain samples were significantly (r=0.596-0.750, p<0.01) positively correlated with the concentrations obtained in the paired surface runoff samples. The anions tested showed a clear spatial distribution, and higher concentrations were observed in the upper reaches of rivers, sea waters near the coast, and rain-surface runoff pairs sampled in urban areas. Our results revealed that precipitation may act as an important source of perchlorate, iodide and thiocyanate in surface water. Moreover, iodide concentrations in the Haihe River and Dagu Drainage Canal showed a good correlation with an ideal marker (acesulfame) of domestic waste water, indicating that input from domestic waste water was an important source of iodide in the surface waters of Tianjin. Copyright © 2014 Elsevier Ltd. All rights reserved.

Potentiometric Surface of the Upper Floridan Aquifer in the St. Johns River Water Management District and Vicinity, Florida, May 2009

USGS Publications Warehouse

Kinnaman, Sandra L.; Dixon, Joann F.

2009-01-01

This map depicts the potentiometric surface of the Upper Floridan aquifer in the St. Johns River Water Management District and vicinity for May 2009. Potentiometric contours are based on water-level measurements collected at 625 wells during the period May 14 - May 29, near the end of the dry season. Some contours are inferred from previous potentiometric-surface maps with larger well networks. The potentiometric surface of the carbonate Upper Floridan aquifer responds mainly to rainfall, and more locally, to groundwater withdrawals and spring flow. Potentiometric-surface highs generally correspond to topographic highs where the aquifer is recharged. Springs and areas of diffuse upward leakage naturally discharge water from the aquifer and are most prevalent along the St. Johns River. Areas of discharge are reflected by depressions in the potentiometric surface. Groundwater withdrawals locally have lowered the potentiometric surface. Groundwater in the Upper Floridan aquifer generally flows from potentiometric highs to potentiometric lows in a direction perpendicular to the contours.

Influence of water on the surface of graphene

NASA Astrophysics Data System (ADS)

Kaya, Yunus; Kalkan, Yalçin; Veenhof, Rob

2018-02-01

We have studied how water modifies the surface of graphene and in particular how the surface conductivity of graphene is affected. According to the literature, two types of interactions should be distinguished: physical, where a water molecule remains intact and is located at some distance from the mesh, and chemical, where a water molecule is imbricated in the graphene bond structure. We have developed theoretical models for both types of interactions using the density functional theory (DFT) with the B3LYP hybrid functional combined with the 6-31G(d) basis set. Our calculations show that the surface conductivity of graphene is reduced in the presence of water.

Total Nitrogen Concentrations in Surface Water of Typical Agro- and Forest Ecosystems in China, 2004-2009

PubMed Central

Xu, Zhiwei; Zhang, Xinyu; Xie, Juan; Yuan, Guofu; Tang, Xinzhai; Sun, Xiaomin; Yu, Guirui

2014-01-01

We assessed the total nitrogen (N) concentrations of 28 still surface water (lake and pond), and 42 flowing surface water (river), monitoring sites under 29 typical terrestrial ecosystems of the Chinese Ecosystem Research Network (CERN) using monitoring data collected between 2004 and 2009. The results showed that the median total N concentrations of still surface water were significantly higher in the agro- (1.5 mg·L−1) and oasis agro- ecosystems (1.8 mg·L−1) than in the forest ecosystems (1.0 mg·L−1). This was also the case for flowing surface water, with total N concentrations of 2.4 mg·L−1, 1.8 mg·L−1 and 0.5 mg·L−1 for the agro-, oasis agro- and forest ecosystems, respectively. In addition, more than 50% of the samples in agro- and oasis agro- ecosystems were seriously polluted (>1.0 mg·L−1) by N. Spatial analysis showed that the total N concentrations in northern and northwestern regions were higher than those in the southern region for both still and flowing surface waters under agro- and oasis agro- ecosystems, with more than 50% of samples exceeding 1.0 mg·L−1 (the Class III limit of the Chinese National Quality Standards for Surface Waters) in surface water in the northern region. Nitrogen pollution in agro- ecosystems is mainly due to fertilizer applications, while the combination of fertilizer and irrigation exacerbates nitrogen pollution in oasis agro- ecosystems. PMID:24667701

The spatial-temporal dynamics of open surface water bodies in CONUS during 1984-2016

NASA Astrophysics Data System (ADS)

Zou, Z.; Xiao, X.; Dong, J.; Qin, Y.; Doughty, R.; Menarguez, M.; Wang, J.

2017-12-01

Open surface water bodies provided 80% of the total water withdrawals in the Contiguous United States (CONUS) in 1985-2010. The inter-annual variability and changing trends of surface water body areas have various impacts on the human society and ecosystems. This study made use of all Landsat 5, 7, and 8 surface reflectance archives ( 370,000 images) during 1984-2016 and a water index- and pixel-based approach to detect and map open surface water bodies in the cloud-based platform of Google Earth Engine. The year-long water body area and annual average water body area were calculated for each of the last 33 years and their inter-annual variations during 1984-2016 were analyzed through anomaly analysis while their changing trends were analyzed through linear regressions. The national annual average water body areas varied from 265,000 to 281,000 km2 during 1984-2016, which is 3% below to 3% above the mean value 274,000 km2. In state level, significant decreasing trends were found in both year-long and annual average water body areas in some states of dry climates in west and southwest U.S., including Oregon, Nevada, Utah, Arizona, New Mexico, and Oklahoma. In comparison, significant increasing trends were found in some states of wet climates in the southeast and north U.S., including Indiana, Ohio, New Jersey, Delaware, Virginia, Tennessee, North Carolina, South Carolina, Louisiana, Alabama, Georgia, North Dakota and South Dakota. Open surface water body areas in CONUS decreased in relatively dry areas but increased in relatively wet areas. The relationships between open surface water body area variability and climate factors (precipitation, temperature) and human impacts (water exploitation) were also analyzed.

Effect of Concentration on the Interfacial and Bulk Structure of Ionic Liquids in Aqueous Solution.

PubMed

Cheng, H-W; Weiss, H; Stock, P; Chen, Y-J; Reinecke, C R; Dienemann, J-N; Mezger, M; Valtiner, M

2018-02-27

Bio and aqueous applications of ionic liquids (IL) such as catalysis in micelles formed in aqueous IL solutions or extraction of chemicals from biologic materials rely on surface-active and self-assembly properties of ILs. Here, we discuss qualitative relations of the interfacial and bulk structuring of a water-soluble surface-active IL ([C 8 MIm][Cl]) on chemically controlled surfaces over a wide range of water concentrations using both force probe and X-ray scattering experiments. Our data indicate that IL structuring evolves from surfactant-like surface adsorption at low IL concentrations, to micellar bulk structure adsorption above the critical micelle concentration, to planar bilayer formation in ILs with <1 wt % of water and at high charging of the surface. Interfacial structuring is controlled by mesoscopic bulk structuring at high water concentrations. Surface chemistry and surface charges decisively steer interfacial ordering of ions if the water concentration is low and/or the surface charge is high. We also demonstrate that controlling the interfacial forces by using self-assembled monolayer chemistry allows tuning of interfacial structures. Both the ratio of the head group size to the hydrophobic tail volume as well as the surface charging trigger the bulk structure and offer a tool for predicting interfacial structures. Based on the applied techniques and analyses, a qualitative prediction of molecular layering of ILs in aqueous systems is possible.

Dynamics of ice nucleation on water repellent surfaces.

PubMed

Alizadeh, Azar; Yamada, Masako; Li, Ri; Shang, Wen; Otta, Shourya; Zhong, Sheng; Ge, Liehui; Dhinojwala, Ali; Conway, Ken R; Bahadur, Vaibhav; Vinciquerra, A Joseph; Stephens, Brian; Blohm, Margaret L

2012-02-14

Prevention of ice accretion and adhesion on surfaces is relevant to many applications, leading to improved operation safety, increased energy efficiency, and cost reduction. Development of passive nonicing coatings is highly desirable, since current antiicing strategies are energy and cost intensive. Superhydrophobicity has been proposed as a lead passive nonicing strategy, yet the exact mechanism of delayed icing on these surfaces is not clearly understood. In this work, we present an in-depth analysis of ice formation dynamics upon water droplet impact on surfaces with different wettabilities. We experimentally demonstrate that ice nucleation under low-humidity conditions can be delayed through control of surface chemistry and texture. Combining infrared (IR) thermometry and high-speed photography, we observe that the reduction of water-surface contact area on superhydrophobic surfaces plays a dual role in delaying nucleation: first by reducing heat transfer and second by reducing the probability of heterogeneous nucleation at the water-substrate interface. This work also includes an analysis (based on classical nucleation theory) to estimate various homogeneous and heterogeneous nucleation rates in icing situations. The key finding is that ice nucleation delay on superhydrophobic surfaces is more prominent at moderate degrees of supercooling, while closer to the homogeneous nucleation temperature, bulk and air-water interface nucleation effects become equally important. The study presented here offers a comprehensive perspective on the efficacy of textured surfaces for nonicing applications.

Water resources data for Indiana, 1968

USGS Publications Warehouse

,

1969-01-01

The surface-water records for the 1968 water year for gaging stations, partial-record stations, and miscellaneous sties within the State of Indiana are given in this report. For convenience there are also included records for a few pertinent gaging stations in bordering States. Water-resources investigations of the U.S. Geological Survey include the collection of water quality data on the chemical and physical characteristics of surface- and ground-water supplies of the Nation. These data for the 1968 water year for the quality of surface water in Indiana are presented in this report.

Exploring the differences of antibiotic resistance genes profiles between river surface water and sediments using metagenomic approach.

PubMed

Jiang, Haoyu; Zhou, Renjun; Zhang, Mengdi; Cheng, Zhineng; Li, Jun; Zhang, Gan; Chen, Baowei; Zou, Shichun; Yang, Ying

2018-05-30

To better understand the potential genic communication and dissemination of antibiotic resistance genes (ARGs) in different environmental matrices, the differences of ARG profiles between river surface water and sediments were explored. Metagenomic analysis was applied to investigate the comprehensive ARG profiles in water and sediment samples collected from the highly human-impacted catchment of the Beijiang River and its river source. A total of 135 ARG subtypes belonging to 18 ARG types were identified. Generally, ARGs in surface water were more diverse and abundant than those in sediments. ARG profiles in the surface water and sediment samples were distinct from each other, but some ARGs were shared by the surface water and sediments. Results revealed that multidrug and bacitracin resistance genes were the predominant ARGs types in both surface water (0.30, 0.17 copies/cell) and sediments (0.19, 0.15 copies/cell). 73 ARG subtypes were shared by the water and sediment samples and had taken over 90% of the total detected ARG abundance. Most of the shared ARGs are resistant to the clinically relevant antibiotics. Furthermore, significant correlations between the ARGs and 21 shared genera or mobile genetic elements (MGEs) (plasmids and integrons) were found in surface water and sediments, suggesting the important role of genera or MGEs in shaping ARGs profiles, propagation and distribution. These findings provide deeper insight into mitigating the propagation of ARGs and the associated risks to public health. Copyright © 2018 Elsevier Inc. All rights reserved.

Seasonal variation of nitrogen-concentration in the surface water and its relationship with land use in a catchment of northern China.

PubMed

Chen, Li-ding; Peng, Hong-jia; Fu, Bo-Jie; Qiu, Jun; Zhang, Shu-rong

2005-01-01

Surface waters can be contaminated by human activities in two ways: (1) by point sources, such as sewage treatment discharge and storm-water runoff; and (2) by non-point sources, such as runoff from urban and agricultural areas. With point-source pollution effectively controlled, non-point source pollution has become the most important environmental concern in the world. The formation of non-point source pollution is related to both the sources such as soil nutrient, the amount of fertilizer and pesticide applied, the amount of refuse, and the spatial complex combination of land uses within a heterogeneous landscape. Land-use change, dominated by human activities, has a significant impact on water resources and quality. In this study, fifteen surface water monitoring points in the Yuqiao Reservoir Basin, Zunhua, Hebei Province, northern China, were chosen to study the seasonal variation of nitrogen concentration in the surface water. Water samples were collected in low-flow period (June), high-flow period (July) and mean-flow period (October) from 1999 to 2000. The results indicated that the seasonal variation of nitrogen concentration in the surface water among the fifteen monitoring points in the rainfall-rich year is more complex than that in the rainfall-deficit year. It was found that the land use, the characteristics of the surface river system, rainfall, and human activities play an important role in the seasonal variation of N-concentration in surface water.

The relationship between surface tension and the industrial performance of water-soluble polymers prepared from acid hydrolysis lignin, a saccharification by-product from woody materials.

PubMed

Matsushita, Yasuyuki; Imai, Masanori; Iwatsuki, Ayuko; Fukushima, Kazuhiko

2008-05-01

In this study, water-soluble anionic and cationic polymers were prepared from sulfuric acid lignin (SAL), an acid hydrolysis lignin, and the relationship between the surface tension of these polymers and industrial performance was examined. The SAL was phenolized (P-SAL) to enhance its solubility and reactivity. Sulfonation and the Mannich reaction with aminocarboxylic acids produced water-soluble anionic polymers and high-dispersibility gypsum paste. The dispersing efficiency increased as the surface tension decreased, suggesting that the fluidity of the gypsum paste increased with the polymer adsorption on the gypsum particle surface. Water-soluble cationic polymers were prepared using the Mannich reaction with dimethylamine. The cationic polymers showed high sizing efficiency under neutral papermaking conditions; the sizing efficiency increased with the surface tension. This suggests that the polymer with high hydrophilicity spread in the water and readily adhered to the pulp surface and the rosin, showing good retention.

Surface-water quality-assurance plan for the Wisconsin district of the U. S. Geological Survey, Water Resources Division

USGS Publications Warehouse

Garn, H.S.

2002-01-01

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

Surface water records of Colorado, 1961

USGS Publications Warehouse

U.S. Geological Survey, Water Resources Division

1961-01-01

The surface-water records for the 1961 water year for gaging stations and miscellaneous sites within the State of Colorado are given in this report. For convenience there are also included records for a few pertinent gaging stations in bordering States. The records were collected and computed by the Water Resources Division of the U.S. Geological Survey, under the direction of W. T. Miller, district engineer, Surface Water Branch, succeeded by J. W. Odell.

Estuarine water-quality and sediment data, and surface-water and ground-water-quality data, Naval Submarine Base Kings Bay, Camden County, Georgia, January 1999

USGS Publications Warehouse

Leeth, David C.; Holloway, Owen G.

2000-01-01

In January 1999, the U.S. Geological Survey collected estuarine-water, estuarine-sediment, surface-water, and ground-water quality samples in the vicinity of Naval Submarine Base Kings Bay, Camden County, Georgia. Data from these samples are used by the U.S. Navy to monitor the impact of submarine base activities on local water resources. Estuarine water and sediment data were collected from five sites on the Crooked River, Kings Bay, and Cumberland Sound. Surface-water data were collected from seven streams that discharge from Naval Submarine Base, Kings Bay. Ground-water data were collected from six ground-water monitoring wells completed in the water-table zone of the surficial aquifer at Naval Submarine Base Kings Bay. Samples were analyzed for nutrients, total and dissolved trace metals, total and dissolved organic carbon, oil and grease, total organic halogens, biological and chemical oxygen demand, and total and fecal coliform. Trace metals in ground and surface waters did not exceed U.S. Environmental Protection Agency Drinking Water Standards; and trace metals in surface water also did not exceed U.S. Environmental Protection Agency Surface Water Standards. These trace metals included arsenic, barium, cadmium, chromium, copper, lead, mercury, selenium, silver, tin, and zinc. Barium was detected in relatively high concentrations in ground water (concentrations ranged from 18 to 264 micrograms per liter). Two estuarine water samples exceeded the Georgia Department of Natural Resources, Environmental Protection Division standards for copper (concentrations of 6.2 and 3.0 micrograms per liter).

Quantification of surface charge density and its effect on boundary slip.

PubMed

Jing, Dalei; Bhushan, Bharat

2013-06-11

Reduction of fluid drag is important in the micro-/nanofluidic systems. Surface charge and boundary slip can affect the fluid drag, and surface charge is also believed to affect boundary slip. The quantification of surface charge and boundary slip at a solid-liquid interface has been widely studied, but there is a lack of understanding of the effect of surface charge on boundary slip. In this paper, the surface charge density of borosilicate glass and octadecyltrichlorosilane (OTS) surfaces immersed in saline solutions with two ionic concentrations and deionized (DI) water with different pH values and electric field values is quantified by fitting experimental atomic force microscopy (AFM) electrostatic force data using a theoretical model relating the surface charge density and electrostatic force. Results show that pH and electric field can affect the surface charge density of glass and OTS surfaces immersed in saline solutions and DI water. The mechanisms of the effect of pH and electric field on the surface charge density are discussed. The slip length of the OTS surface immersed in saline solutions with two ionic concentrations and DI water with different pH values and electric field values is measured, and their effects on the slip length are analyzed from the point of surface charge. Results show that a larger absolute value of surface charge density leads to a smaller slip length for the OTS surface.

Models of Fate and Transport of Pollutants in Surface Waters

ERIC Educational Resources Information Center

Okome, Gloria Eloho

2013-01-01

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

Protecting Surface Water Systems on Forest Sites Through Herbicide Use

Treesearch

J.L. Michael; H.L. Gibbs; J.B. Fischer; E.C. Webber

2000-01-01

Sediment, nutrients, and pesticides are universally accepted as the greatest threats to surface water quality world-wide. Sedimentation in surface waters is a natural phenomenon, but is magnified by human activities. Intensive forest management practices, particularly road building, harvesting and planting site preparation, result in the greatest increases in erosion...

40 CFR 279.45 - Used oil storage at transfer facilities.

Code of Federal Regulations, 2010 CFR

2010-07-01

... containment system from migrating out of the system to the soil, groundwater, or surface water. (e) Secondary... into the containment system from migrating out of the system to the soil, groundwater, or surface water... system to the soil, groundwater, or surface water. (g) Labels. (1) Containers and aboveground tanks used...

40 CFR 279.45 - Used oil storage at transfer facilities.

Code of Federal Regulations, 2012 CFR

2012-07-01

... containment system from migrating out of the system to the soil, groundwater, or surface water. (e) Secondary... into the containment system from migrating out of the system to the soil, groundwater, or surface water... system to the soil, groundwater, or surface water. (g) Labels. (1) Containers and aboveground tanks used...

40 CFR 279.45 - Used oil storage at transfer facilities.

Code of Federal Regulations, 2014 CFR

2014-07-01

... containment system from migrating out of the system to the soil, groundwater, or surface water. (e) Secondary... into the containment system from migrating out of the system to the soil, groundwater, or surface water... system to the soil, groundwater, or surface water. (g) Labels. (1) Containers and aboveground tanks used...

40 CFR 279.45 - Used oil storage at transfer facilities.

Code of Federal Regulations, 2011 CFR

2011-07-01

... containment system from migrating out of the system to the soil, groundwater, or surface water. (e) Secondary... into the containment system from migrating out of the system to the soil, groundwater, or surface water... system to the soil, groundwater, or surface water. (g) Labels. (1) Containers and aboveground tanks used...

40 CFR 279.45 - Used oil storage at transfer facilities.

Code of Federal Regulations, 2013 CFR

2013-07-01

... containment system from migrating out of the system to the soil, groundwater, or surface water. (e) Secondary... into the containment system from migrating out of the system to the soil, groundwater, or surface water... system to the soil, groundwater, or surface water. (g) Labels. (1) Containers and aboveground tanks used...

78 FR 6149 - Final Interim Staff Guidance Assessing the Radiological Consequences of Accidental Releases of...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-29

... Accidental Releases of Radioactive Materials From Liquid Waste Tanks in Ground and Surface Waters for... Radioactive Materials from Liquid Waste Tanks in Ground and Surface Waters for Combined License Applications... Radioactive Materials from Liquid Waste Tanks in Ground and Surface Waters for Combined License Applications...

Soil, Groundwater, Surface Water, and Sediments of Kennedy Space Center, Florida: Background Chemical and Physical Characteristics

NASA Technical Reports Server (NTRS)

Shmalzer, Paul A.; Hensley, Melissa A.; Mota, Mario; Hall, Carlton R.; Dunlevy, Colleen A.

2000-01-01

This study documented background chemical composition of soils, groundwater, surface; water, and sediments of Kennedy Space Center. Two hundred soil samples were collected, 20 each in 10 soil classes. Fifty-one groundwater wells were installed in 4 subaquifers of the Surficial Aquifer and sampled; there were 24 shallow, 16 intermediate, and 11 deep wells. Forty surface water and sediment samples were collected in major watershed basins. All samples were away from sites of known contamination. Samples were analyzed for organochlorine pesticides, aroclors, chlorinated herbicides, polycyclic aromatic hydrocarbons (PAH), total metals, and other parameters. All aroclors (6) were below detection in all media. Some organochlorine pesticides were detected at very low frequencies in soil, sediment, and surface water. Chlorinated herbicides were detected at very low frequencies in soil and sediments. PAH occurred in low frequencies in soiL, shallow groundwater, surface water, and sediments. Concentrations of some metals differed among soil classes, with subaquifers and depths, and among watershed basins for surface water but not sediments. Most of the variation in metal concentrations was natural, but agriculture had increased Cr, Cu, Mn, and Zn.

The calming effect of oil on water

NASA Astrophysics Data System (ADS)

Behroozi, Peter; Cordray, Kimberly; Griffin, William; Behroozi, Feredoon

2007-05-01

The calming effect of oil on water has been known since ancient times. Benjamin Franklin was the first to investigate the effect, but the underlying mechanism for this striking phenomenon remains elusive. We used a miniature laser interferometer to measure the amplitude of surface waves to a resolution of ±5nm, making it possible to determine the effect of an oil monolayer on the attenuation of capillary waves and the surface dilational modulus of the monolayer. We present attenuation data on pure water, water covered by olive oil, water covered by a fatty acid, and a water-acetone mixture for comparison. From the attenuation data at frequencies between 251 and 551Hz, we conclude that the calming effect of oil on surface waves is principally due to the dissipation of wave energy caused by the Gibbs surface elasticity of the monolayer, with only a secondary contribution from the reduction in surface tension. Our data also indicate that the surface-dilational viscosity of the oil monolayer is negligible and plays an insignificant role in calming the waves.

Perfluoroalkyl acids in surface waters and tapwater in the Qiantang River watershed-Influences from paper, textile, and leather industries.

PubMed

Lu, Guo-Hui; Gai, Nan; Zhang, Peng; Piao, Hai-Tao; Chen, Shu; Wang, Xiao-Chun; Jiao, Xing-Chun; Yin, Xiao-Cai; Tan, Ke-Yan; Yang, Yong-Liang

2017-10-01

Perfluoroalkyl acids (PFAAs) are widely used as multi-purpose surfactants or water/oil repellents. In order to understand the contamination level and compositional profiles of PFAAs in aqueous environment in textile, leather, and paper making industrial areas, surface waters and tap waters were collected along the watershed of the Qiantang River where China's largest textile, leather, and paper making industrial bases are located. For comparison, surface water and tapwater samples were also collected in Hangzhou and its adjacent areas. 17 PFAAs were analyzed by solid phase extraction-high performance liquid chromatography-tandem mass spectrometry. The results show that the total concentrations of PFAAs (ΣPFAAs) in the Qiantang River waters ranged from 106.1 to 322.9 ng/L, averaging 164.2 ng/L. The contamination levels have been found to be extremely high, comparable to the levels of the most serious PFAA contamination in surface waters of China. The PFAA composition profiles were characterized by the dominant PFOA (average 58.1% of the total PFAAs), and PFHxA (average 18.8%). The ΣPFAAs in tap water ranged from 9.5 to 174.8 ng/L, showing PFAA compositional pattern similar to the surface waters. Good correlations between PFAA composition profiles in tap waters and the surface waters were observed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Development of a Model to Correct Multi-View Angle above Water Measurements for the Analysis of the Bidirectional Reflectance of Coral and Other Reef Substrates

NASA Astrophysics Data System (ADS)

Miller, I.; Forster, B. C.; Laffan, S. W.

2012-07-01

Spectral reflectance characteristics of substrates in a coral reef environment are often measured in the field by viewing a substrate at nadir. However, viewing a substrate from multiple angles would likely result in different spectral characteristics for most coral reef substrates and provide valuable information on structural properties. To understand the relationship between the morphology of a substrate and its spectral response it is necessary to correct the observed above-water radiance for the effects of atmosphere and water attenuation, at a number of view and azimuth angles. In this way the actual surface reflectance can be determined. This research examines the air-water surface interaction for two hypothetical atmospheric conditions (clear Rayleigh scattering and totally cloudcovered) and the global irradiance reaching the benthic surface. It accounts for both water scattering and absorption, with simplifications for shallow water conditions, as well as the additive effect of background reflectance being reflected at the water-air surface at angles greater than the critical refraction angle (~48°). A model was developed to correct measured above-water radiance along the refracted view angle for its decrease due to path attenuation and the "n squared law of radiance" and the additive surface reflectance. This allows bidirectional benthic surface reflectance and nadir-normalised reflectance to be determined. These theoretical models were adapted to incorporate above-water measures relative to a standard, diffuse, white reference panel. The derived spectral signatures of a number of coral and non-coral benthic surfaces compared well with other published results, and the signatures and nadir normalised reflectance of the corals and other benthic surface classes indicate good class separation.

Effects of Dimethyl Sulfoxide on Surface Water near Phospholipid Bilayers.

PubMed

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 (X DMSO ), 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 X DMSO (≲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.

Salinization and arsenic contamination of surface water in southwest Bangladesh.

PubMed

Ayers, John C; George, Gregory; Fry, David; Benneyworth, Laura; Wilson, Carol; Auerbach, Leslie; Roy, Kushal; Karim, Md Rezaul; Akter, Farjana; Goodbred, Steven

2017-09-11

To identify the causes of salinization and arsenic contamination of surface water on an embanked island (i.e., polder) in the tidal delta plain of SW Bangladesh we collected and analyzed water samples in the dry (May) and wet (October) seasons in 2012-2013. Samples were collected from rice paddies (wet season), saltwater ponds used for brine shrimp aquaculture (dry season), freshwater ponds and tidal channels (both wet and dry season), and rainwater collectors. Continuous measurements of salinity from March 2012 to February 2013 show that tidal channel water increases from ~0.15 ppt in the wet season up to ~20 ppt in the dry season. On the polder, surface water exceeds the World Health Organization drinking water guideline of 10 μg As/L in 78% of shrimp ponds and 27% of rice paddies, raising concerns that produced shrimp and rice could have unsafe levels of As. Drinking water sources also often have unsafe As levels, with 83% of tubewell and 43% of freshwater pond samples having >10 μg As/L. Water compositions and field observations are consistent with shrimp pond water being sourced from tidal channels during the dry season, rather than the locally saline groundwater from tubewells. Irrigation water for rice paddies is also obtained from the tidal channels, but during the wet season when surface waters are fresh. Salts become concentrated in irrigation water through evaporation, with average salinity increasing from 0.43 ppt in the tidal channel source to 0.91 ppt in the rice paddies. Our observations suggest that the practice of seasonally alternating rice and shrimp farming in a field has a negligible effect on rice paddy water salinity. Also, shrimp ponds do not significantly affect the salinity of adjacent surface water bodies or subjacent groundwater because impermeable shallow surface deposits of silt and clay mostly isolate surface water bodies from each other and from the shallow groundwater aquifer. Bivariate plots of conservative element concentrations show that all surface water types lie on mixing lines between dry season tidal channel water and rainwater, i.e., all are related by varying degrees of salinization. High As concentrations in dry season tidal channel water and shrimp ponds likely result from groundwater exfiltration and upstream irrigation in the dry season. Arsenic is transferred from tidal channels to rice paddies through irrigation. Including groundwater samples from the same area (Ayers et al. in Geochem Trans 17:1-22, 2016), principal components analysis and correlation analysis reveal that salinization explains most variation in surface water compositions, whereas progressive reduction of buried surface water by dissolved organic carbon is responsible for the nonconservative behavior of S, Fe, and As and changes in Eh and alkalinity of groundwater.

Drinking water: a major source of lead exposure in Karachi, Pakistan.

PubMed

Ul-Haq, N; Arain, M A; Badar, N; Rasheed, M; Haque, Z

2011-11-01

Excess lead in drinking water is a neglected source of lead toxicity in Pakistan. A cross-sectional survey in 2007/08 was made of water samples from drinking water sources in Karachi, a large industrial city. This study aimed to compare lead levels between untreated ground water and treated surface (tap) water in 18 different districts. Of 216 ground and surface water samples collected, 86% had lead levels higher than the World Health Organization maximum acceptable concentration of l0 ppb. Mean lead concentration in ground water [146 (SD 119) ppb] was significantly higher than in surface water [77.1 (SD 54) ppb]. None of the 18 districts had a mean lead level of ground or surface water below the WHO cut-off and ground water sources in 9 districts had a severe level of contamination (>150 ppb). Urgent action is needed to eliminate sources of contamination.

Foulant Characteristics Comparison in Recycling Cooling Water System Makeup by Municipal Reclaimed Water and Surface Water in Power Plant

PubMed Central

Ping, Xu; Jing, Wang; Yajun, Zhang; Jie, Wang; Shuai, Si

2015-01-01

Due to water shortage, municipal reclaimed water rather than surface water was replenished into recycling cooling water system in power plants in some cities in China. In order to understand the effects of the measure on carbon steel corrosion, characteristics of two kinds of foulant produced in different systems were studied in the paper. Differences between municipal reclaimed water and surface water were analyzed firstly. Then, the weight and the morphology of two kinds of foulant were compared. Moreover, other characteristics including the total number of bacteria, sulfate reducing bacteria, iron bacteria, extracellular polymeric substance (EPS), protein (PN), and polysaccharide (PS) in foulant were analyzed. Based on results, it could be concluded that microbial and corrosive risk would be increased when the system replenished by municipal reclaimed water instead of surface water. PMID:25893132

Methane evasion and oxidation in the Big Cypress National Preserve—a low relief carbonate wetland

NASA Astrophysics Data System (ADS)

Ward, N. D.; Bianchi, T. S.; Cohen, M. J.; Martin, J. B.; Quintero, C.; Brown, A.; Osborne, T.; Sawakuchi, H. O.

2016-12-01

The Big Cypress National Preserve is a low relief carbonate wetland characterized by unique basin patterning known as "cypress domes." Here we examine the concentration and stable isotopic composition of methane in pore waters, surface waters, and bubbles from the sediment across horizontal gradients in four domes during three sampling campaigns. The proportion of methane oxidized in surface waters was estimated based on isotopic differences between surface water and pore waters/bubbles. Rates of methane evasion from surface waters, soils, and cypress knees to the atmosphere were also measured. Surface water CH4 concentrations ranged from 170 to 4,533 ppm with the highest levels generally being observed during wet periods. Pore water CH4 concentrations ranged from 748 to 75,213 ppm. The concentration of methane in bubbles ranged from 6.5 to 71%. The stable isotopic composition of CH4 ranged from -69.2 to -43.8‰ for all samples and was generally more enriched in surface waters compared to bubbles and porewaters, particularly in the two domes that were persistently inundated throughout the year. Based on these isotopic values, the average percentage of surface water CH4 that was oxidized was 37 ± 16% (maximum of 67%) and 19 ± 4% (maximum of 47%) in the two domes that are persistently inundated versus the two domes that are not inundated during the dry season, respectively. The average rate of CH4 evasion was 3.6 ± 1.6 mmol m-2 d-1 via diffusion, 7.6 ± 4.7 mmol m-2 d-1 via ebullition, 10.9 ± 11.4 mmol m-2 d-1­ from soil surfaces, and 34.3 ± 27.4 mmol m-2 d-1 from cypress knees. These results indicate that CH4 is produced in great quantities in inundated sediments, particularly in the center of the cypress domes. Diffusive fluxes from surface waters are suppressed by microbial oxidation in the water column, whereas ebullition from sediments and evasion through cypress knees, and likely other vascular vegetation, are the primary pathways for CH4 outgassing.

Modelling of surface-water temperature for the estimation of the Czech fishery productivity under the climate change

NASA Astrophysics Data System (ADS)

Svobodová, Eva; Trnka, Miroslav; Kopp, Radovan; Mareš, Jan; Dubrovský, Martin; Spurný, Petr; Žalud, Zděněk

2015-04-01

Freshwater fish production is significantly correlated with water temperature which is expected to increase under the climate change. This study is dealing with the estimation of the change of water temperature in productive ponds and its impact on the fishery in the Czech Republic. Calculation of surface-water temperature which was based on three-day mean of the air temperature was developed and tested in several ponds in three main fish production areas. Output of surface-water temperature model was compared with measured data and showed that the lower range of model accuracy is surface-water temperature 3°C, under this temperature threshold the model loses its predictive competence. In the expecting of surface-water temperature above the temperature 3°C the model has proved the well consistence between observed and modelled surface-water temperature (R 0.79 - 0.96). Verified model was applied in the conditions of climate change determined by the pattern scaling method, in which standardised scenarios were derived from five global circulation models MPEH5, CSMK3, IPCM4, GFCM21 and HADGEM. Results were evaluated with regard to thresholds which characterise the fish species requirements on water temperature. Used thresholds involved the upper temperature threshold for fish survival and the tolerable number of days in continual period with mentioned threshold surface-water temperature. Target fish species were Common carp (Cyprinus carpio), Maraene whitefish (Coregonus maraena), Northern whitefish (Coregonus peled) and Rainbow trout (Oncorhynchus mykis). Results indicated the limitation of the Czech fish-farming in terms of i) the increase of the length of continual periods with surface-water temperature above the threshold appropriate to given fish species toleration, ii) the increase of the number of continual periods with surface-water temperature above the threshold, both appropriate to given fish species toleration, and iii) the increase of overall number of days within the continual period with temperature above the threshold tolerated by given fish species. ACKNOWLEDGEMENTS: This study was funded by project "Building up a multidisciplinary scientific team focused on drought" No. CZ.1.07/2.3.00/20.0248.

Effects of surface roughness and energy on ice adhesion strength

NASA Astrophysics Data System (ADS)

Zou, M.; Beckford, S.; Wei, R.; Ellis, C.; Hatton, G.; Miller, M. A.

2011-02-01

The aim of this study is to investigate the effects of surface roughness and surface energy on ice adhesion strength. Sandblasting technique was used to prepare samples with high roughness. Silicon-doped hydrocarbon and fluorinated-carbon thin films were employed to alter the surface energy of the samples. Silicon-doped hydrocarbon films were deposited by plasma-enhanced chemical vapor deposition, while fluorinated-carbon films were produced using deep reactive ion etching equipment by only activating the passivation step. Surface topographies were characterized using scanning electron microscopy and a stylus profilometer. The surface wetting properties were characterized by a video-based contact angle measurement system. The adhesion strength of ice formed from a water droplet on these surfaces was studied using a custom-built shear force test apparatus. It was found that the ice adhesion strength is correlated to the water contact angles of the samples only for surfaces with similar roughness: the ice adhesion strength decreases with the increase in water contact angle. The study also shows that smoother as-received sample surfaces have lower ice adhesion strength than the much rougher sandblasted surfaces.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aytug, Tolga; Simpson, John T.; Lupini, Andrew R.

Inspired by highly non-wetting natural biological surfaces (e.g., lotus leaves and water strider legs), artificial superhydrophobic surfaces that exhibit water droplet contact angles exceeding 150o have previously been constructed by utilizing various synthesis strategies.[ , , ] Such bio-inspired, water-repellent surfaces offer significant potential for numerous uses ranging from marine applications (e.g., anti-biofouling, anti-corrosion), anti-condensation (e.g., anti-icing, anti-fogging), membranes for selective separation (e.g., oil-water, gas-liquid), microfluidic systems, surfaces requiring reduced maintenance and cleaning, to applications involving glasses and optical materials.[ ] In addition to superhydrophobic attributes, for integration into device systems that have extended operational limits and overall improved performance,more » surfaces that also possess multifunctional characteristics are desired, where the functionality should match to the application-specific requirements.« less

Optical methods in modeling nicotine effect on the surface water of cell membranes

NASA Astrophysics Data System (ADS)

Alexandrova, Tatyana V.; Rogacheva, Svetlana M.; Kuznetsov, Pavel E.; Gubina, Tamara I.

2005-06-01

Fluorescence and spectrophotometric methods have been used for investigation of nicotine action on the state and mobility of the surface water. The surfaces of membranes and proteins were simulated with the help of liposomes and ultradispersive diamonds consequently. Nicotine was shown to reduce the stability of liposomes and to change the aggregative ability of ultradispersive diamonds. The wave-like curves for the nicotine concentration dependences of the pointed features were observed. Such shape of responses was suggested to be due to the changing in structure and dynamics of water hydrogen bonds net near the surface of the model systems induced by nicotine molecules. The surface water phase was supposed to be one of signal elements ofthe ligand receptor recognition process.

Summary of reported agriculture and irrigation water use in Monroe County, Arkansas, 1991

USGS Publications Warehouse

Holland, T.W.; Manning, C.A.; Stafford, K.L.

1993-01-01

This report summarizes the 1991 water-use reporting through the Conservation District Office in Monroe County, Arkansas. The number of withdrawal registrations for Monroe County was 1,886 (1,677 groundwater and 209 surface water). Water withdrawals reported during the registration process total 8.87 Mgal/d (5.75 Mgal/d groundwater and 3.12 Mgal/d surface water) for agriculture and 210.61 Mgal/d (190.99 Mgal/d groundwater and 19.62 Mgal/d surface water) for irrigation. The registration reports for 1991 indicate that this water was applied to 127,670 acres of land to irrigate rice, sorghum, soybeans, milo, cash grains, cotton, hay, and unknown crops, as well as for agricultural uses of animal aquaculture, minnows, and ducks. {descriptors: *Water use, *Arkansas, *Monroe County, Selective withdrawal, Groundwater, Surface water

Surface studies of low molecular weight photolysis products from UV-ozone oxidised polystyrene

NASA Astrophysics Data System (ADS)

Davidson, M. R.; Mitchell, S. A.; Bradley, R. H.

2005-05-01

The production of low molecular weight oxidised material during UV-ozone treatment of polystyrene has been studied by XPS, GC-MS, FTIR and UV/visible spectroscopy. XPS analysis of the oxidised polystyrene surfaces before and after washing with water or methanol indicates that the removal of oxidation products and the surface that remains after washing is strongly dependent on the choice of solvent. Methanol washing removes a greater proportion of the more highly oxidised carbonyl and carboxyl groups resulting in a surface with a lower oxygen content than that remaining after water washing. Extended exposure to UV-ozone treatment reveals a two-stage oxidation process with mono-substituted benzene rings such as benzaldehyde, acetophenone and benzoic acid being produced at exposure times less than 15 min. Compounds, more typical of those formed via dehydration reactions of existing oxidised species, are produced at longer exposure times. UV-visible spectroscopy and Fourier transform infrared spectroscopy also confirm the presence of carboxylic acid, aromatic ketones and esters. Measurements of water contact angle on a 10 min treated surface reveals that methanol washing produces a more hydrophilic surface than water washing, the resulting water contact angles being 47° and 62° respectively. Ageing of methanol washed surfaces for 24 h leads to a recovery of the water contact angle back to 62° which suggests some form of post-washing surface relaxation process. Since XPS analyses show no increase in the oxygen concentration of the methanol washed surfaces after a 24 h ageing period, the increase in contact angle found with ageing is attributed to the reorientation of very near-surface functional groups i.e. within the XPS sampling depth.

Measurement of the oxygen mass transfer through the air-water interface.

PubMed

Mölder, Erik; Mashirin, Alelxei; Tenno, Toomas

2005-01-01

Gas mass transfer through the liquid-gas interface has enormous importance in various natural and industrial processes. Surfactants or insoluble compounds adsorbed onto an interface will inhibit the gas mass transfer through the liquid-gas surface. This study presents a technique for measuring the oxygen mass transfer through the air-water interface. Experimental data obtained with the measuring device were incorporated into a novel mathematical model, which allowed one to calculate diffusion conduction of liquid surface layer and oxygen mass transfer coefficient in the liquid surface layer. A special measurement cell was constructed. The most important part of the measurement cell is a chamber containing the electrochemical oxygen sensor inside it. Gas exchange between the volume of the chamber and the external environment takes place only through the investigated surface layer. Investigated liquid was deoxygenated, which triggers the oxygen mass transfer from the chamber through the liquid-air interface into the liquid phase. The decrease of oxygen concentration in the cell during time was measured. By using this data it is possible to calculate diffusional parameters of the water surface layer. Diffusion conduction of oxygen through the air-water surface layer of selected wastewaters was measured. The diffusion conduction of different wastewaters was about 3 to 6 times less than in the unpolluted water surface. It was observed that the dilution of wastewater does not have a significant impact on the oxygen diffusion conduction through the wastewater surface layer. This fact can be explained with the presence of the compounds with high surface activity in the wastewater. Surfactants achieved a maximum adsorption and, accordingly, the maximum decrease of oxygen permeability already at a very low concentration of surfactants in the solution. Oxygen mass transfer coefficient of the surface layer of the water is found to be Ds/ls = 0.13 x 10(-3) x cm/s. A simple technique for measuring oxygen diffusion parameters through the air-water solution surface has been developed. Derived equations enable the calculation of diffusion parameters of the surface layer at current conditions. These values of the parameters permit one to compare the resistances of the gas-liquid interface to oxygen mass transfer in the case of adsorption of different substances on the surface layer. This simple technique may be used for a determination of oxygen permeability of different water-solution surface layers. It enables one to measure the resistance to the oxygen permeability of all inflowing wastewater surface layers in the wastewater treatment plant, and to initiate a preliminary cleaning of this wastewater if required. Similarly, we can measure oxygen permeability of natural waterbodies. Especially in the case of pollution, it is important to know to what extent the oxygen permeability of the water surface layer has been decreased. Based on the tehnique presented in this research, fieldwork equipment will be developed.

The annual and interannual variabilities of precipitable water, surface wind speed, and sea surface temperature over the tropical Pacific

NASA Technical Reports Server (NTRS)

Liu, W. Timothy

1989-01-01

The Nimbus-7 Scanning Multichannel Microwave Radiometer (SSMR) provided simultaneous measurements of three geophysical parameters, each of which describing a certain aspect of the evolution of the 1982-1983 ENSO: the sea-surface temperature (T), precipitable water (W), and surface-wind speed (U). In this paper, values derived from the SSMR were compared with in situ measurements from ships, research buoys, and operational island stations in the tropical Pacific between January 1980 and October 1983, demonstrating the temporal and spatial coherence of the SSMR measurements. The results show that the variabilities of the surface convergence, sea surface temperature, and precipitable water are related. It was found that W anomalies were not always colocated with T anomalies, and that W anomalies were often associated with negative U anomalies, interpreted as surface convergence.

Langmuir circulation inhibits near-surface water turbulence

NASA Astrophysics Data System (ADS)

Schultz, Colin

2012-07-01

In the surface ocean, breaking waves are a major source of air bubbles and turbulent kinetic energy. During the presence of a consistent surface wind, these wave-generated bubbles, along with other surface material like seaweed or foam, can be drawn into long rows along the surface. Driving this organization is Langmuir circulation, a phenomenon in which the wind and waves cause surface waters to rotate helically, moving like a wire wrapped around a pole in the windward direction. These spiral currents oscillate between clockwise and counterclockwise rotations, such that in some places the surface waters are pushed together and in others they are pulled apart. Researchers have previously found that at sites of convergence the bubbles produced by breaking waves are pushed to depths of 15 meters or more, with important implications for air-sea gas mixing and other processes.

Inventory of File sref_em.t03z.pgrb212.p1.f06.grib2

Science.gov Websites

surface WEASD 6 hour fcst Water Equivalent of Accumulated Snow Depth [kg/m^2] 016 surface APCP 0-6 hour surface WEASD 0-6 hour acc Water Equivalent of Accumulated Snow Depth [kg/m^2] 019 surface CSNOW 6 hour -6 hour acc Large-Scale Precipitation (non-convective) [kg/m^2] 415 surface SNOM 0-6 hour acc Snow

Chemical Composition of Surfaces of Polycrystalline Silver Held in Water Vapor

NASA Astrophysics Data System (ADS)

Ashkhotov, O. G.; Khubezhov, S. A.; Aleroev, M. A.; Grigorkina, G. S.; Ashkhotova, I. B.; Magkoev, T. T.; Bliev, A. P.; Ramonova, A. G.; Kibizov, D. D.

2018-01-01

The chemical composition of surfaces and near-surface layers of massive polycrystalline silver held in water vapor for 2 h at 1073 K is studied via Auger and X-ray photoelectron spectroscopy. It is shown that the oxygen on a surface is in the molecular state. In near-surface layers at depths of up to 8 nm, it is predominantly in the atomic state typical of chemisorbed Ag2O.

Microwave Imager Measures Sea Surface Temperature Through Clouds

NASA Technical Reports Server (NTRS)

2002-01-01

This image was acquired over Tropical Atlantic and U.S. East Coast regions on Aug. 22 - Sept. 23, 1998. Cloud data were collected by the Geostationary Operational Environmental Satellite (GOES). Sea Surface Temperature (SST) data were collected aboard the NASA/NASDA Tropical Rainfall Measuring Mission (TRMM) satellite by The TRMM Microwave Imager (TMI). TMI is the first satellite microwave sensor capable of accurately measuring sea surface temperature through clouds, as shown in this scene. For years scientists have known there is a strong correlation between sea surface temperature and the intensity of hurricanes. But one of the major stumbling blocks for forecasters has been the precise measurement of those temperatures when a storm begins to form. In this scene, clouds have been made translucent to allow an unobstructed view of the surface. Notice Hurricane Bonnie approaching the Carolina Coast (upper left) and Hurricane Danielle following roughly in its path (lower right). The ocean surface has been falsely colored to show a map of water temperature--dark blues are around 75oF, light blues are about 80oF, greens are about 85oF, and yellows are roughly 90oF. A hurricane gathers energy from warm waters found at tropical latitudes. In this image we see Hurricane Bonnie cross the Atlantic, leaving a cooler trail of water in its wake. As Hurricane Danielle followed in Bonnie's path, the wind speed of the second storm dropped markedly, as available energy to fuel the storm dropped off. But when Danielle left Bonnie's wake, wind speeds increased due to temperature increases in surface water around the storm. As a hurricane churns up the ocean, it's central vortex draws surface heat and water into the storm. That suction at the surface causes an upwelling of deep water. At depth, tropical ocean waters are significantly colder than water found near the surface. As they're pulled up to meet the storm, those colder waters essentially leave a footprint in the storm's wake which might last as long as two weeks. Forecasters can quantify the difference in surface temperatures between this footprint and the surrounding temperatures and use that information to better predict storm intensity. If another storm intersects with this cold water trail, it is likely to lose significant strength due to the fact that the colder water does not contain as much potential energy as warm water. TRMM Fact Sheet Predicting Hurricane Intensity Far from Land Remote Sensing Systems Image courtesy TRMM Project, Remote Sensing Systems, and Scientific Visualization Studio, NASA Goddard Space Flight Center

Surface Wave Velocity of Crosslinked Polyacrylate Gels

NASA Astrophysics Data System (ADS)

Matsuoka, Tatsuro; Kinouchi, Wataru; ShinobuKoda, ShinobuKoda; Nomura, Hiroyasu

1999-05-01

Surface wave velocities of crosslinked polyacrylate hydrogelswere measured as a function of water content with differentcompositions of sodium polyacrylate (NaPA) and polyacrylic acid (PAA).The water content and composition dependencies of the surface wavevelocity were discussed.

The Dynamic Surface Tension of Water

PubMed Central

2017-01-01

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. PMID:28301160

The Dynamic Surface Tension of Water.

PubMed

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

2017-04-06

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.

Ozone treatment of coal- and coffee grounds-based active carbons: Water vapor adsorption and surface fractal micropores

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsunoda, Ryoichi; Ozawa, Takayoshi; Ando, Junichi

1998-09-15

Characteristics of the adsorption iostherms of water vapor on active carbons from coal and coffee grounds and those ozonized ones from the surface fractal dimension analysis are discussed. The upswing of the adsorption isotherms in the low relative pressure of coffee grounds-based active carbon, of which isotherms were not scarcely affected on ozonization, was attributed to the adsorption of water molecules on the metallic oxides playing the role of oxygen-surface complexes, which formed the corrugated surfaces on the basal planes of micropore walls with the surface fractal dimension D{sub s} > 2. On the other hand, coal-based active carbon withmore » D{sub s} < 2, which indicated the flat surfaces of micropore walls, showed little effect on the upswing even on ozonization, even though the adsorption amounts of water vapor were increased in the low relative pressure.« less

An all-water-based system for robust superhydrophobic surfaces.

PubMed

Liu, Mingming; Hou, Yuanyuan; Li, Jing; Tie, Lu; Guo, Zhiguang

2018-06-01

Superhydrophobic surfaces with micro-/nanohierarchical structures are mechanically weak. Generally, organic solvents are used to dissolve or disperse organic adhesives and modifiers to enhance the mechanical strength of superhydrophobic surfaces. In this work, an all-water-based spraying solution is developed for the preparation of robust superhydrophobic surfaces, which contains ZnO nanoparticles, aluminum phosphate as an inorganic adhesive, and polytetrafluoroethylene with low surface energy. The all-water-based system is appreciated for low price and less pollution. Importantly, the prepared superhydrophobic surfaces are durable enough against various harsh conditions (such as UV irradiation for 12 h, pH values from 1 to 13, and temperatures from -10 to 300 °C for 12 h) and physical damages (including sandpaper abrasion and sand impact tests for 50 cycles). In addition, the obtained interfacial materials show promise for practical applications such as anti-icing and oil-water separation. Copyright © 2018 Elsevier Inc. All rights reserved.

Water-Surface Elevations, Discharge, and Water-Quality Data for Selected Sites in the Warm Springs Area near Moapa, Nevada

USGS Publications Warehouse

Beck, David A.; Ryan, Roslyn; Veley, Ronald J.; Harper, Donald P.; Tanko, Daron J.

2006-01-01

The U.S. Geological Survey, in cooperation with Southern Nevada Water Authority and the Nevada Division of Water Resources, operates and maintains a surface-water monitoring network of 6 continuous-record stream-flow gaging stations and 11 partial-record stations in the Warm Springs area near Moapa, Nevada. Permanent land-surface bench marks were installed within the Warm Springs area by the Las Vegas Valley Water District, the Southern Nevada Water Authority, and the U.S. Geological Survey to determine water-surface elevations at all network monitoring sites. Vertical datum elevation and horizontal coordinates were established for all bench marks through a series of Differential Global Positioning System surveys. Optical theodolite surveys were made to transfer Differential Global Positioning System vertical datums to reference marks installed at each monitoring site. The surveys were completed in June 2004 and water-surface elevations were measured on August 17, 2004. Water-surface elevations ranged from 1,810.33 feet above North American Vertical Datum of 1988 at a stream-gaging station in the Pederson Springs area to 1,706.31 feet at a station on the Muddy River near Moapa. Discharge and water-quality data were compiled for the Warm Springs area and include data provided by the U.S. Geological Survey, Nevada Division of Water Resources, U.S. Fish and Wildlife Service, Moapa Valley Water District, Desert Research Institute, and Converse Consultants. Historical and current hydrologic data-collection networks primarily are related to changes in land- and water-use activities in the Warm Springs area. These changes include declines in ranching and agricultural use, the exportation of water to other areas of Moapa Valley, and the creation of a national wildlife refuge. Water-surface elevations, discharge, and water-quality data compiled for the Warm Springs area will help identify (1) effects of changing vegetation within the former agricultural lands, (2) effects of restoration activities in the wildlife refuge, and (3) potential impacts of ground-water withdrawals.

Surface energy changes produced by ultraviolet-ozone irradiation of poly(methylmethacrylate), polycarbone and polytetrafluoroethylene

NASA Technical Reports Server (NTRS)

Ponter, A. B.; Jones, W. R., Jr.; Jansen, R. H.

1994-01-01

Contact angles of water and methylene iodide were measured as a function of UV/O3 treatment time for three polymers: poly(methylmethacrylate) (PMMA), polycarbonate, and polytetrafluoroethylene (PTFE). Surface roughnesses were also measured. Surface free energies were then calculated using relationships developed by Kaelble and Neumann. The surface energy of polycarbonate was found to increase (60 percent) during UV/O3 treatment. However, calculations on PMMA were hampered by the formation of a water soluble surface product. On PTFE surfaces, the UV/O3 treatment etched the surface causing large increases in surface roughness, rendering contact angle measurements impossible. It is concluded that care must be taken in interpreting contact angle measurements and surface energy calculations on UV/O3 treated polymer surfaces.

Vibrational spectroscopic study of pH dependent solvation at a Ge(100)-water interface during an electrode potential triggered surface termination transition

NASA Astrophysics Data System (ADS)

Niu, Fang; Rabe, Martin; Nayak, Simantini; Erbe, Andreas

2018-06-01

The charge-dependent structure of interfacial water at the n-Ge(100)-aqueous perchlorate interface was studied by controlling the electrode potential. Specifically, a joint attenuated total reflection infrared spectroscopy and electrochemical experiment was used in 0.1M NaClO4 at pH ≈ 1-10. The germanium surface transformation to an H-terminated surface followed the thermodynamic Nernstian pH dependence and was observed throughout the entire pH range. A singular value decomposition-based spectra deconvolution technique coupled to a sigmoidal transition model for the potential dependence of the main components in the spectra shows the surface transformation to be a two-stage process. The first stage was observed together with the first appearance of Ge-H stretching modes in the spectra and is attributed to the formation of a mixed surface termination. This transition was reversible. The second stage occurs at potentials ≈0.1-0.3 V negative of the first one, shows a hysteresis in potential, and is attributed to the formation of a surface with maximum Ge-H coverage. During the surface transformation, the surface becomes hydrophobic, and an effective desolvation layer, a "hydrophobic gap," developed with a thickness ≈1-3 Å. The largest thickness was observed near neutral pH. Interfacial water IR spectra show a loss of strongly hydrogen-bound water molecules compared to bulk water after the surface transformation, and the appearance of "free," non-hydrogen bound OH groups, throughout the entire pH range. Near neutral pH at negative electrode potentials, large changes at wavenumbers below 1000 cm-1 were observed. Librational modes of water contribute to the observed changes, indicating large changes in the water structure.

Continuous measurements of water surface height and width along a 6.5km river reach for discharge algorithm development

NASA Astrophysics Data System (ADS)

Tuozzolo, S.; Durand, M. T.; Pavelsky, T.; Pentecost, J.

2015-12-01

The upcoming Surface Water and Ocean Topography (SWOT) satellite will provide measurements of river width and water surface elevation and slope along continuous swaths of world rivers. Understanding water surface slope and width dynamics in river reaches is important for both developing and validating discharge algorithms to be used on future SWOT data. We collected water surface elevation and river width data along a 6.5km stretch of the Olentangy River in Columbus, Ohio from October to December 2014. Continuous measurements of water surface height were supplemented with periodical river width measurements at twenty sites along the study reach. The water surface slope of the entire reach ranged from during 41.58 cm/km at baseflow to 45.31 cm/km after a storm event. The study reach was also broken into sub-reaches roughly 1km in length to study smaller scale slope dynamics. The furthest upstream sub-reaches are characterized by free-flowing riffle-pool sequences, while the furthest downstream sub-reaches were directly affected by two low-head dams. In the sub-reaches immediately upstream of each dam, baseflow slope is as low as 2 cm/km, while the furthest upstream free-flowing sub-reach has a baseflow slope of 100 cm/km. During high flow events the backwater effect of the dams was observed to propagate upstream: sub-reaches impounded by the dams had increased water surface slopes, while free flowing sub-reaches had decreased water surface slopes. During the largest observed flow event, a stage change of 0.40 m affected sub-reach slopes by as much as 30 cm/km. Further analysis will examine height-width relationships within the study reach and relate cross-sectional flow area to river stage. These relationships can be used in conjunction with slope data to estimate discharge using a modified Manning's equation, and are a core component of discharge algorithms being developed for the SWOT mission.

Revealing Surface Waters on an Antifreeze Protein by Fusion Protein Crystallography Combined with Molecular Dynamic Simulations.

PubMed

Sun, Tianjun; Gauthier, Sherry Y; Campbell, Robert L; Davies, Peter L

2015-10-08

Antifreeze proteins (AFPs) adsorb to ice through an extensive, flat, relatively hydrophobic surface. It has been suggested that this ice-binding site (IBS) organizes surface waters into an ice-like clathrate arrangement that matches and fuses to the quasi-liquid layer on the ice surface. On cooling, these waters join the ice lattice and freeze the AFP to its ligand. Evidence for the generality of this binding mechanism is limited because AFPs tend to crystallize with their IBS as a preferred protein-protein contact surface, which displaces some bound waters. Type III AFP is a 7 kDa globular protein with an IBS made up two adjacent surfaces. In the crystal structure of the most active isoform (QAE1), the part of the IBS that docks to the primary prism plane of ice is partially exposed to solvent and has clathrate waters present that match this plane of ice. The adjacent IBS, which matches the pyramidal plane of ice, is involved in protein-protein crystal contacts with few surface waters. Here we have changed the protein-protein contacts in the ice-binding region by crystallizing a fusion of QAE1 to maltose-binding protein. In this 1.9 Å structure, the IBS that fits the pyramidal plane of ice is exposed to solvent. By combining crystallography data with MD simulations, the surface waters on both sides of the IBS were revealed and match well with the target ice planes. The waters on the pyramidal plane IBS were loosely constrained, which might explain why other isoforms of type III AFP that lack the prism plane IBS are less active than QAE1. The AFP fusion crystallization method can potentially be used to force the exposure to solvent of the IBS on other AFPs to reveal the locations of key surface waters.

Using computational modeling of river flow with remotely sensed data to infer channel bathymetry

USGS Publications Warehouse

Nelson, Jonathan M.; McDonald, Richard R.; Kinzel, Paul J.; Shimizu, Y.

2012-01-01

As part of an ongoing investigation into the use of computational river flow and morphodynamic models for the purpose of correcting and extending remotely sensed river datasets, a simple method for inferring channel bathymetry is developed and discussed. The method is based on an inversion of the equations expressing conservation of mass and momentum to develop equations that can be solved for depth given known values of vertically-averaged velocity and water-surface elevation. The ultimate goal of this work is to combine imperfect remotely sensed data on river planform, water-surface elevation and water-surface velocity in order to estimate depth and other physical parameters of river channels. In this paper, the technique is examined using synthetic data sets that are developed directly from the application of forward two-and three-dimensional flow models. These data sets are constrained to satisfy conservation of mass and momentum, unlike typical remotely sensed field data sets. This provides a better understanding of the process and also allows assessment of how simple inaccuracies in remotely sensed estimates might propagate into depth estimates. The technique is applied to three simple cases: First, depth is extracted from a synthetic dataset of vertically averaged velocity and water-surface elevation; second, depth is extracted from the same data set but with a normally-distributed random error added to the water-surface elevation; third, depth is extracted from a synthetic data set for the same river reach using computed water-surface velocities (in place of depth-integrated values) and water-surface elevations. In each case, the extracted depths are compared to the actual measured depths used to construct the synthetic data sets (with two- and three-dimensional flow models). Errors in water-surface elevation and velocity that are very small degrade depth estimates and cannot be recovered. Errors in depth estimates associated with assuming water-surface velocities equal to depth-integrated velocities are substantial, but can be reduced with simple corrections.

Trend-outflow method for understanding interactions of surface water with groundwater and atmospheric water for eight reaches of the Upper Rio Grande

NASA Astrophysics Data System (ADS)

Liu, Yi; Sheng, Zhuping

2011-11-01

SummaryAtmospheric water, surface water, and groundwater interact very actively through hydrologic processes such as precipitation, infiltration, seepage, irrigation, drainage, evaporation, and evapotranspiration in the Upper Rio Grande Basin. A trend-outflow method has been developed in this paper to gain a better understanding of the interactions based on cumulated inflow and outflow data for any river reaches of interest. A general trend-outflow equation was derived by associating the net interaction of surface water with atmospheric water as a polynomial of inflow and the net interaction of surface water with groundwater as a constant based on surface water budget. Linear and quadratic relations are probably two common trend-outflow types in the real world. It was found that trend-outflows of the Upper Rio Grande reaches, Española, Albuquerque, Socorro-Engle, Palomas, and Rincon are linear with inflow, while those of reaches, Belen, Mesilla and Hueco are quadratic. Reaches Belen, Mesilla and Hueco are found as water deficit reaches mainly for irrigated agriculture in extreme drought years.

Biomimetic Water-Collecting Fabric with Light-Induced Superhydrophilic Bumps.

PubMed

Wang, Yuanfeng; Wang, Xiaowen; Lai, Chuilin; Hu, Huawen; Kong, Yeeyee; Fei, Bin; Xin, John H

2016-02-10

To develop an efficient water-collecting surface that integrates both fast water-capturing and easy drainage properties is of high current interest for addressing global water issues. In this work, a superhydrophobic surface was fabricated on cotton fabric via manipulation of both the surface roughness and surface energy. This was followed by a subsequent spray coating of TiO2 nanosol that created light-induced superhydrophilic bumps with a unique raised structure as a result of the interfacial tension of the TiO2 nanosol sprayed on the superhydrophobic fiber surface. These raised TiO2 bumps induce both a wettability gradient and a shape gradient, synergistically accelerating water coalescence and water collection. The in-depth study revealed that the quantity and the distribution of the TiO2 had a significant impact on the final water collection efficiency. This inexpensive and facilely fabricated fabric biomimicks the desert beetle's back and spider silk, which are capable of fog harvesting without additional energy consumption.

Environmental monitoring of water resources around a municipal landfill of the Rio Grande do Sul state, Brazil.

PubMed

de Medeiros Engelmann, Pâmela; Dos Santos, Victor Hugo Jacks Mendes; Moser, Letícia Isabela; do Canto Bruzza, Eduardo; Barbieri, Cristina Barazzetti; Barela, Pâmela Susin; de Moraes, Diogo Pompéu; Augustin, Adolpho Herbert; Goudinho, Flávio Soares; Melo, Clarissa Lovato; Ketzer, João Marcelo Medina; Rodrigues, Luiz Frederico

2017-09-01

In Brazil, landfills are commonly used as a method for the final disposal of waste that is compliant with the legislation. This technique, however, presents a risk to surface water and groundwater resources, owing to the leakage of metals, anions, and organic compounds. The geochemical monitoring of water resources is therefore extremely important, since the leachate can compromise the quality and use of surface water and groundwater close to landfills. In this paper, the results of analyses of metals, anions, ammonia, and physicochemical parameters were used to identify possible contamination of surface water and groundwater in a landfill area. A statistical multivariate approach was used. The values found for alkali metals, nitrate, and chloride indicate contamination in the regional groundwater and, moreover, surface waters also show variation when compared to the other background points, mainly for ammonia. Thus, the results of this study evidence the landfill leachate influence on the quality of groundwater and surface water in the study area.

Urban evaporation rates for water-permeable pavements.

PubMed

Starke, P; Göbel, P; Coldewey, W G

2010-01-01

In urban areas the natural water balance is disturbed. Infiltration and evaporation are reduced, resulting in a high surface runoff and a typical city climate, which can lead to floods and damages. Water-permeable pavements have a high infiltration rate that reduces surface runoff by increasing the groundwater recharge. The high water retention capacity of the street body of up to 51 l/m(2) and its connection via pores to the surface lead to higher evaporation rates than impermeable surfaces. A comparison of these two kinds of pavements shows a 16% increase in evaporation levels of water-permeable pavements. Furthermore, the evaporation from impermeable pavements is linked directly to rain events due to fast-drying surfaces. Water-permeable pavements show a more evenly distributed evaporation after a rain event. Cooling effects by evaporative heat loss can improve the city climate even several days after rain events. On a large scale use, uncomfortable weather like sultriness or dry heat can be prevented and the urban water balance can be attenuated towards the natural.

77 FR 14717 - National Oil and Hazardous Substances Pollution Contingency Plan; National Priorities List...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-13

... preclude future actions under Superfund. This partial deletion pertains to the surface soil, unsaturated subsurface soil, surface water and sediments of Operable Unit (OU) 1, the Gateway Lake Ash Study Area, and.... Surface soil, unsaturated subsurface soil, surface water, and sediments at OU-2, OU-3, OU-4, OU-5, OU-6...

Evaporation from a sphagnum moss surface

Treesearch

D.S. Nichols; J.M. Brown

1980-01-01

Peat cores, 45 cm in diameter, were collected from a sphagnum bog in northern Minnesota, and used to measure the effects of different temperatures and water levels on evaporation from a sphagnum moss surface in a growth chamber. Under all conditions, evaporation from the moss surface was greater than that from a free-water surface. Evaporation from the moss increased...

Water adsorption on TiO2 surfaces probed by soft X-ray spectroscopies: bulk materials vs. isolated nanoparticles

PubMed Central

Benkoula, Safia; Sublemontier, Olivier; Patanen, Minna; Nicolas, Christophe; Sirotti, Fausto; Naitabdi, Ahmed; Gaie-Levrel, François; Antonsson, Egill; Aureau, Damien; Ouf, François-Xavier; Wada, Shin-Ichi; Etcheberry, Arnaud; Ueda, Kiyoshi; Miron, Catalin

2015-01-01

We describe an experimental method to probe the adsorption of water at the surface of isolated, substrate-free TiO2 nanoparticles (NPs) based on soft X-ray spectroscopy in the gas phase using synchrotron radiation. To understand the interfacial properties between water and TiO2 surface, a water shell was adsorbed at the surface of TiO2 NPs. We used two different ways to control the hydration level of the NPs: in the first scheme, initially solvated NPs were dried and in the second one, dry NPs generated thanks to a commercial aerosol generator were exposed to water vapor. XPS was used to identify the signature of the water layer shell on the surface of the free TiO2 NPs and made it possible to follow the evolution of their hydration state. The results obtained allow the establishment of a qualitative determination of isolated NPs’ surface states, as well as to unravel water adsorption mechanisms. This method appears to be a unique approach to investigate the interface between an isolated nano-object and a solvent over-layer, paving the way towards new investigation methods in heterogeneous catalysis on nanomaterials. PMID:26462615

Interactions between groundwater and surface water: The state of the science

USGS Publications Warehouse

Sophocleous, M.

2002-01-01

The interactions between groundwater and surface water are complex. To understand these interactions in relation to climate, landform, geology, and biotic factors, a sound hydrogeoecological framework is needed. All these aspects are synthesized and exemplified in this overview. In addition, the mechanisms of interactions between groundwater and surface water (GW-SW) as they affect recharge-discharge processes are comprehensively outlined, and the ecological significance and the human impacts of such interactions are emphasized. Surface-water and groundwater ecosystems are viewed as linked components of a hydrologic continuum leading to related sustainability issues. This overview concludes with a discussion of research needs and challenges facting this evolving field. The biogeochemical processes within the upper few centimeters of sediments beneath nearly all surface-water bodies (hyporheic zone) have a profound effect on the chemistry of the water interchange, and here is where most of the recent research has been focusing. However, to advance conceptual and other modeling of GW-SW systems, a broader perspective of such interactions across and between surface-water bodies is needed, including multidimensional analyses, interface hydraulic characterization and spatial variability, site-to-region regionalization approaches, as well as cross-disciplinary collaborations.

Connection Zones, Surface Water - Groundwater: Aquifers Associated To Niger Central Delta, In Mali.

NASA Astrophysics Data System (ADS)

Kone, S.

2016-12-01

Surface water infiltration recharging Mali aquifers occurs through, underlying perched hydrogeological networks, lacustrine zones of the Central Delta or inundation valleys. The mapping of both the Surface water and the Groundwater, their types and availabilities, are briefly presented, and the focus of the study is on the types of hydraulic connections between these water bodies. The aquifers hydraulically connected to the Niger Central Delta flows systems are Continental Terminal/Quaternary, and they concern some areas where either inundation or perennial surface water flow occurs. These aquifers belong to the hydrogeological Unit of Central Delta where the recharge by surface water is estimated to be five percent of the flow loss between the entry and the outlet of this hydrological system. Some attempts of simulation along with a review based on the first studies synthetized in "Synthese Hydrogeologique du Mali" would permit to pave the way to other studies on these hydraulically connected zones in Mali. A previews simulation study, about mapping the potential rate of pumping capacity, corroborates some observed structural characteristics and leads to subdivide the area in two hydrogeological sectors, and the present simulation studies focus on the sector "Macina -Diaka" where surface water are in hydraulic relation with groundwater.

Roles of surface water areas for water and solute cycle in Hanoi city, Viet Nam

NASA Astrophysics Data System (ADS)

Hayashi, Takeshi; Kuroda, Keisuke; Do Thuan, An; Tran Thi Viet, Nga; Takizawa, Satoshi

2013-04-01

Hanoi city, the capital of Viet Nam, has developed beside the Red river. Recent rapid urbanization of this city has reduced a large number of natural water areas such as lakes, ponds and canals not only in the central area but the suburban area. Contrary, the urbanization has increased artificial water areas such as pond for fish cultivation and landscaping. On the other hand, the urbanization has induced the inflow of waste water from households and various kinds of factories to these water areas because of delay of sewerage system development. Inflow of the waste water has induced eutrophication and pollution of these water areas. Also, there is a possibility of groundwater pollution by infiltration of polluted surface water. However, the role of these water areas for water cycle and solute transport is not clarified. Therefore, this study focuses on the interaction between surface water areas and groundwater in Hanoi city to evaluate appropriate land development and groundwater resource management. We are carrying out three approaches: a) understanding of geochemical characteristics of surface water and groundwater, b) monitoring of water levels of pond and groundwater, c) sampling of soil and pond sediment. Correlation between d18O and dD of precipitation (after GNIP), the Red River (after GNIR) and the water samples of this study showed that the groundwater is composed of precipitation, the Red River and surface water that has evaporation process. Contribution of the surface water with evaporation process was widely found in the study area. As for groundwater monitoring, the Holocene aquifers at two sites were in unconfined condition in dry season and the groundwater levels in the aquifer continued to increase through rainy season. The results of isotopic analysis and groundwater level monitoring showed that the surface water areas are one of the major groundwater sources. On the other hand, concentrations of dissolved Arsenic (filtered by 0.45um) in the pore water of the pond sediments were much higher than the pond water and closed to that of groundwater. Also, other metal elements showed the same trend. This result suggested that Arsenic and other metal elements recharged to these ponds is probably adsorbed and removed by sediments (including organic matters). That is, pond sediment plays an important role for solute transport as a filter of Arsenic and metal elements. The results of this study strongly suggest that the natural and artificial surface water areas have important roles for water cycle and solute transport in Hanoi city. Although the number of the natural water areas is decreasing, dredging of artificial water areas increases the infiltration from the surface to aquifers. Therefore, qualitative and quantitative preservation of the surface water areas is important for conservation of groundwater environment and contribute to sustainable groundwater management in Hanoi city.

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

NASA Astrophysics Data System (ADS)

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.

Assessment of the contamination of drinking water supply wells by pesticides from surface water resources using a finite element reactive transport model and global sensitivity analysis techniques

NASA Astrophysics Data System (ADS)

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

2013-01-01

SummaryA reactive transport model is employed to evaluate the potential for contamination of drinking water wells by surface water pollution. The model considers various geologic settings, includes sorption and degradation processes and is tested by comparison with data from a tracer experiment where fluorescein dye injected in a river is monitored at nearby drinking water wells. Three compounds were considered: an older pesticide MCPP (Mecoprop) which is mobile and relatively persistent, glyphosate (Roundup), a newer biodegradable and strongly sorbing pesticide, and its degradation product AMPA. Global sensitivity analysis using the Morris method is employed to identify the dominant model parameters. Results show that the characteristics of clay aquitards (degree of fracturing and thickness), pollutant properties and well depths are crucial factors when evaluating the risk of drinking water well contamination from surface water. This study suggests that it is unlikely that glyphosate in streams can pose a threat to drinking water wells, while MCPP in surface water can represent a risk: MCPP concentration at the drinking water well can be up to 7% of surface water concentration in confined aquifers and up to 10% in unconfined aquifers. Thus, the presence of confining clay aquitards may not prevent contamination of drinking water wells by persistent compounds in surface water. Results are consistent with data on pesticide occurrence in Denmark where pesticides are found at higher concentrations at shallow depths and close to streams.

Application of a laser Doppler vibrometer for air-water to subsurface signature detection

NASA Astrophysics Data System (ADS)

Land, Phillip; Roeder, James; Robinson, Dennis; Majumdar, Arun

2015-05-01

There is much interest in detecting a target and optical communications from an airborne platform to a platform submerged under water. Accurate detection and communications between underwater and aerial platforms would increase the capabilities of surface, subsurface, and air, manned and unmanned vehicles engaged in oversea and undersea activities. The technique introduced in this paper involves a Laser Doppler Vibrometer (LDV) for acousto-optic sensing for detecting acoustic information propagated towards the water surface from a submerged platform inside a 12 gallon water tank. The LDV probes and penetrates the water surface from an aerial platform to detect air-water surface interface vibrations caused by an amplifier to a speaker generating a signal generated from underneath the water surface (varied water depth from 1" to 8"), ranging between 50Hz to 5kHz. As a comparison tool, a hydrophone was used simultaneously inside the water tank for recording the acoustic signature of the signal generated between 50Hz to 5kHz. For a signal generated by a submerged platform, the LDV can detect the signal. The LDV detects the signal via surface perturbations caused by the impinging acoustic pressure field; proving a technique of transmitting/sending information/messages from a submerged platform acoustically to the surface of the water and optically receiving the information/message using the LDV, via the Doppler Effect, allowing the LDV to become a high sensitivity optical-acoustic device. The technique developed has much potential usage in commercial oceanography applications. The present work is focused on the reception of acoustic information from an object located underwater.

Surface Freshwater Storage and Variability in the Amazon Basin from Multi-Satellite Observations, 1993-2007

NASA Technical Reports Server (NTRS)

Papa, Fabrice; Frappart, Frederic; Guntner, Andreas; Prigent, Catherine; Aires, Filipe; Getirana, Augusto; Maurer, Raffael

2013-01-01

The amount of water stored and moving through the surface water bodies of large river basins (river, floodplains, wetlands) plays a major role in the global water and biochemical cycles and is a critical parameter for water resources management. However, the spatio-temporal variations of these freshwater reservoirs are still widely unknown at the global scale. Here, we propose a hypsographic curve approach to estimate surface freshwater storage variations over the Amazon basin combining surface water extent from a multi-satellite-technique with topographic data from the Global Digital Elevation Model (GDEM) from Advance Spaceborne Thermal Emission and Reflection Radiometer (ASTER). Monthly surface water storage variations for 1993-2007 are presented, showing a strong seasonal and interannual variability, and are evaluated against in situ river discharge and precipitation. The basin-scale mean annual amplitude of approx. 1200 cu km is in the range of previous estimates and contributes to about half of the Gravity Recovery And Climate Experiment (GRACE) total water storage variations. For the first time, we map the surface water volume anomaly during the extreme droughts of 1997 (October-November) and 2005 (September-October) and found that during these dry events the water stored in the river and flood-plains of the Amazon basin was, respectively, approx. 230 (approx. 40%) and 210 (approx. 50%) cu km below the 1993-2007 average. This new 15year data set of surface water volume represents an unprecedented source of information for future hydrological or climate modeling of the Amazon. It is also a first step toward the development of such database at the global scale.

Fractal behavior of soil water storage at multiple depths

NASA Astrophysics Data System (ADS)

Ji, Wenjun; Lin, Mi; Biswas, Asim; Si, Bing C.; Chau, Henry W.; Cresswell, Hamish P.

2016-08-01

Spatiotemporal behavior of soil water is essential to understand the science of hydrodynamics. Data intensive measurement of surface soil water using remote sensing has established that the spatial variability of soil water can be described using the principle of self-similarity (scaling properties) or fractal theory. This information can be used in determining land management practices provided the surface scaling properties are kept at deep layers. The current study examined the scaling properties of sub-surface soil water and their relationship to surface soil water, thereby serving as supporting information for plant root and vadose zone models. Soil water storage (SWS) down to 1.4 m depth at seven equal intervals was measured along a transect of 576 m for 5 years in Saskatchewan. The surface SWS showed multifractal nature only during the wet period (from snowmelt until mid- to late June) indicating the need for multiple scaling indices in transferring soil water variability information over multiple scales. However, with increasing depth, the SWS became monofractal in nature indicating the need for a single scaling index to upscale/downscale soil water variability information. In contrast, all soil layers during the dry period (from late June to the end of the growing season in early November) were monofractal in nature, probably resulting from the high evapotranspirative demand of the growing vegetation that surpassed other effects. This strong similarity between the scaling properties at the surface layer and deep layers provides the possibility of inferring about the whole profile soil water dynamics using the scaling properties of the easy-to-measure surface SWS data.

Friction Regimes of Water-Lubricated Diamond (111): Role of Interfacial Ether Groups and Tribo-Induced Aromatic Surface Reconstructions

NASA Astrophysics Data System (ADS)

Kuwahara, Takuya; Moras, Gianpietro; Moseler, Michael

2017-09-01

Large-scale quantum molecular dynamics of water-lubricated diamond (111) surfaces in sliding contact reveals multiple friction regimes. While water starvation causes amorphization of the tribological interface, small H2O traces are sufficient to preserve crystallinity. This can result in high friction due to cold welding via ether groups or in ultralow friction due to aromatic surface passivation triggered by tribo-induced Pandey reconstruction. At higher water coverage, Grotthuss-type diffusion and H2O dissociation yield dense H /OH surface passivation leading to another ultralow friction regime.

Interaction between Air Bubbles and Superhydrophobic Surfaces in Aqueous Solutions.

PubMed

Shi, Chen; Cui, Xin; Zhang, Xurui; Tchoukov, Plamen; Liu, Qingxia; Encinas, Noemi; Paven, Maxime; Geyer, Florian; Vollmer, Doris; Xu, Zhenghe; Butt, Hans-Jürgen; Zeng, Hongbo

2015-07-07

Superhydrophobic surfaces are usually characterized by a high apparent contact angle of water drops in air. Here we analyze the inverse situation: Rather than focusing on water repellency in air, we measure the attractive interaction of air bubbles and superhydrophobic surfaces in water. Forces were measured between microbubbles with radii R of 40-90 μm attached to an atomic force microscope cantilever and submerged superhydrophobic surfaces. In addition, forces between macroscopic bubbles (R = 1.2 mm) at the end of capillaries and superhydrophobic surfaces were measured. As superhydrophobic surfaces we applied soot-templated surfaces, nanofilament surfaces, micropillar arrays with flat top faces, and decorated micropillars. Depending on the specific structure of the superhydrophobic surfaces and the presence and amount of entrapped air, different interactions were observed. Soot-templated surfaces in the Cassie state showed superaerophilic behavior: Once the electrostatic double-layer force and a hydrodynamic repulsion were overcome, bubbles jumped onto the surface and fully merged with the entrapped air. On nanofilaments and micropillar arrays we observed in addition the formation of sessile bubbles with finite contact angles below 90° or the attachment of bubbles, which retained their spherical shape.

Experimental und numerical investigations on cooling efficiency of Air-Mist nozzles on steel during continuous casting

NASA Astrophysics Data System (ADS)

Arth, G.; Taferner, M.; Bernhard, C.; Michelic, S.

2016-07-01

Cooling strategies in continuous casting of steel can vary from rapid cooling to slow cooling, mainly controlled by adjusting the amount of water sprayed onto the surface of the product. Inadequate adjustment however can lead to local surface undercooling or reheating, leading to surface and inner defects. This paper focuses on cooling efficiency of Air-Mist nozzles on casted steel and the experimental and numerical prediction of surface temperature distributions over the product width. The first part explains the determination of heat transfer coefficients (HTC) on laboratory scale, using a so called nozzle measuring stand (NMS). Based on measured water distributions and determined HTC's for air-mist nozzles using the NMS, surface temperatures are calculated by a transient 2D-model on a simple steel plate, explained in the second part of this paper. Simulations are carried out varying water impact density and spray water distribution, consequently influencing the local HTC distribution over the plate width. Furthermore, these results will be interpreted with regard to their consequence for surface and internal quality of the cast product. The results reveal the difficulty of correct adjustment of the amount of sprayed water, concurrent influencing water distribution and thus changing HTC distribution and surface temperature.

UV sensitivity of planktonic net community production in ocean surface waters

NASA Astrophysics Data System (ADS)

Regaudie-de-Gioux, Aurore; Agustí, Susana; Duarte, Carlos M.

2014-05-01

The net plankton community metabolism of oceanic surface waters is particularly important as it more directly affects the partial pressure of CO2 in surface waters and thus the air-sea fluxes of CO2. Plankton communities in surface waters are exposed to high irradiance that includes significant ultraviolet blue (UVB, 280-315 nm) radiation. UVB radiation affects both photosynthetic and respiration rates, increase plankton mortality rates, and other metabolic and chemical processes. Here we test the sensitivity of net community production (NCP) to UVB of planktonic communities in surface waters across contrasting regions of the ocean. We observed here that UVB radiation affects net plankton community production at the ocean surface, imposing a shift in NCP by, on average, 50% relative to the values measured when excluding partly UVB. Our results show that under full solar radiation, the metabolic balance shows the prevalence of net heterotrophic community production. The demonstration of an important effect of UVB radiation on NCP in surface waters presented here is of particular relevance in relation to the increased UVB radiation derived from the erosion of the stratospheric ozone layer. Our results encourage design future research to further our understanding of UVB effects on the metabolic balance of plankton communities.

Evaporation of nanoscale water on a uniformly complete wetting surface at different temperatures.

PubMed

Guo, Yuwei; Wan, Rongzheng

2018-05-03

The evaporation of nanoscale water films on surfaces affects many processes in nature and industry. Using molecular dynamics (MD) simulations, we show the evaporation of a nanoscale water film on a uniformly complete wetting surface at different temperatures. With the increase in temperature, the growth of the water evaporation rate becomes slow. Analyses show that the hydrogen bond (H-bond) lifetimes and orientational autocorrelation times of the outermost water film decrease slowly with the increase in temperature. Compared to a thicker water film, the H-bond lifetimes and orientational autocorrelation times of a monolayer water film are much slower. This suggests that the lower evaporation rate of the monolayer water film on a uniformly complete wetting surface may be caused by the constriction of the water rotation due to the substrate. This finding may be helpful for controlling nanoscale water evaporation within a certain range of temperatures.

40 CFR 141.73 - Filtration.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Filtration and Disinfection § 141.73 Filtration. A public water system that uses a surface water source or a ground water source under the direct influence of surface water...

Wetting behavior and drainage of water droplets on microgrooved brass surfaces.

PubMed

Rahman, M Ashiqur; Jacobi, Anthony M

2012-09-18

In the present study, contact angle hysteresis and sliding behavior of water droplets on parallel, periodic microgrooved brass surfaces are investigated experimentally for enhancement of water drainage and compared to that on flat baseline surfaces. The surfaces (a total of 17 microgrooved samples, with a range of groove depth of 22 to 109 μm, pillar width of 26 to 190 μm, and groove width of 103 and 127 μm) are fabricated using a mechanical micromachining process. The wetting state and shape/elongation of deposited water droplets, anisotropy of the contact angle hysteresis, and the drainage behavior of water droplets on the microgrooved surfaces are found to be strongly dependent on the topography of the groove geometry, which is analyzed in detail. The wetting state is found to be Wenzel for microgrooved surfaces with very low aspect ratio (<0.2) and narrow pillars (pillar width to groove width ratio of ≈0.2), and also for the two deepest grooved surfaces of two different sample series, all of which exhibit high contact angle hysteresis. Mechanisms of the advancing and receding motions are identified. The critical sliding angle (the angle from horizontal at incipient motion of the advancing confluence) for the microgrooved surfaces is found to be significantly smaller than for flat surfaces. The sliding angle exhibits significant groove geometry dependence and is found to increase with pillar width and decrease with groove depth. The findings of this study may be useful in a broad range of applications where water retention plays an important role.

Potentiometric surface of the upper Floridan Aquifer in the St. Johns River Water Management District and vicinity, Florida, May 1994

USGS Publications Warehouse

Schiffer, D.M.; O'Reilly, A. M.; Phelps, G.G.; Bradner, L.A.; Halford, K.J.; Spechler, R.M.

1994-01-01

This map depicts the potentiometric surface of the Upper Floridan aquifer in the St. Johns River Water Management District and vicinity for May 1994. The map is based on water-level measurements made at approximately 1,000 wells and several springs. Data on the map were contoured using 5-foot contour intervals in most areas. The potentiometric surface of this karstic aquifer generally reflects land surface topography. Potentiometric surface highs often correspond to topographic highs, which are areas of surficial recharge to the Upper Floridan aquifer. Springs within topographic lows along with areas of more diffuse upward leakage are natural zones of discharge. Municipal, agricultural, and industrial withdrawals have lowered the potentiometric surface in some areas. The potentiometric surface ranged from 125 feet above sea level in Polk County to 32 feet below sea level in Nassau County. Water levels in May 1994 generally were 0 to 3 feet lower than those measured in May 1993. Water levels in May 1994 in northeast Florida generally were 0 to 3 feet higher than in September 1993, except in the lower St. Johns River basin, where water levels were 0 to 4 feet lower than in September 1993. In the rest of the mapped area, water levels in May 1994 generally were 0 to 4 feet lower than those measured in September 1993.

Formation and transport of deethylatrazine and deisopropylatrazine in surface water

USGS Publications Warehouse

Thurman, E.M.; Meyer, M.T.; Mills, M.S.; Zimmerman, L.R.; Perry, C.A.; Goolsby, D.A.

1994-01-01

Field disappearance studies and a regional study of nine rivers in the Midwest Corn Belt show that deethylatrazine (DEA; 2-amino-4-chloro-6-isopropylamino-s-triazine) and deisopropylatrazine (DIA; 2-amino-4-chloro-6-ethylaminos-triazine) occur frequently in surface water that has received runoff from two parent triazine herbicides, atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) and cyanazine (2-chloro-4-ethylamino-6-methylpropionitrileamino-s-triazine). The concentration of DEA and DIA in surface water varies with the hydrologic conditions of the basin and the timing of runoff, with maximum concentrations reaching 5 ??g/L (DEA + DIA). Early rainfall followed by a dry summer will result in an early peak concentration of metabolites in surface water. A wet summer will delay the maximum concentrations of metabolites and increase their runoff into surface water, occasionally resulting in a slight separation of the parent atrazine maximum concentrations from the metabolite maximum concentrations, giving a "second flush?? of triazine metabolites to surface water. Replicated field dissipation studies of atrazine and cyanazine indicate that DIA/DEA ratios will vary from 0.4 ?? 0.1 when atrazine is the major triazine present to 0.6 ?? 0.1 when significant amounts of cyanazine are present. A comparison of transport time of DEA and DIA from field plots to their appearance in surface water indicates that storage and dilution are occurring in the alluvial aquifers of the basin.

On the influence of the intermolecular potential on the wetting properties of water on silica surfaces

NASA Astrophysics Data System (ADS)

Pafong, E.; Geske, J.; Drossel, B.

2016-09-01

We study the wetting properties of water on silica surfaces using molecular dynamics (MD) simulations. To describe the intermolecular interaction between water and silica atoms, two types of interaction potential models are used: the standard BródkA and Zerda (BZ) model and the Gulmen and Thompson (GT) model. We perform an in-depth analysis of the influence of the choice of the potential on the arrangement of the water molecules in partially filled pores and on top of silica slabs. We find that at moderate pore filling ratios, the GT silica surface is completely wetted by water molecules, which agrees well with experimental findings, while the commonly used BZ surface is less hydrophilic and is only partially wetted. We interpret our simulation results using an analytical calculation of the phase diagram of water in partially filled pores. Moreover, an evaluation of the contact angle of the water droplet on top of the silica slab reveals that the interaction becomes more hydrophilic with increasing slab thickness and saturates around 2.5-3 nm, in agreement with the experimentally found value. Our analysis also shows that the hydroaffinity of the surface is mainly determined by the electrostatic interaction, but the van der Waals interaction nevertheless is strong enough that it can turn a hydrophobic surface into a hydrophilic surface.

Review: Impacts of permafrost degradation on inorganic chemistry of surface fresh water

NASA Astrophysics Data System (ADS)

Colombo, Nicola; Salerno, Franco; Gruber, Stephan; Freppaz, Michele; Williams, Mark; Fratianni, Simona; Giardino, Marco

2018-03-01

Recent studies have shown that climate change is impacting the inorganic chemical characteristics of surface fresh water in permafrost areas and affecting aquatic ecosystems. Concentrations of major ions (e.g., Ca2 +, Mg2 +, SO42 -, NO3-) can increase following permafrost degradation with associated deepening of flow pathways and increased contributions of deep groundwater. In addition, thickening of the active layer and melting of near-surface ground ice can influence inorganic chemical fluxes from permafrost into surface water. Permafrost degradation has also the capability to modify trace element (e.g., Ni, Mn, Al, Hg, Pb) contents in surface water. Although several local and regional modifications of inorganic chemistry of surface fresh water have been attributed to permafrost degradation, a comprehensive review of the observed changes is lacking. The goal of this paper is to distil insight gained across differing permafrost settings through the identification of common patterns in previous studies, at global scale. In this review we focus on three typical permafrost configurations (pervasive permafrost degradation, thermokarst, and thawing rock glaciers) as examples and distinguish impacts on (i) major ions and (ii) trace elements. Consequences of warming climate have caused spatially-distributed progressive increases of major ion and trace element delivery to surface fresh water in both polar and mountain areas following pervasive permafrost degradation. Moreover, localised releases of major ions and trace elements to surface water due to the liberation of soluble materials sequestered in permafrost and ground ice have been found in ice-rich terrains both at high latitude (thermokarst features) and high elevation (rock glaciers). Further release of solutes and related transport to surface fresh water can be expected under warming climatic conditions. However, complex interactions among several factors able to influence the timing and magnitude of the impacts of permafrost degradation on inorganic chemistry of surface fresh water (e.g., permafrost sensitivity to thawing, modes of permafrost degradation, characteristics of watersheds) require further conceptual and mechanistic understanding together with quantitative diagnosis of the involved mechanisms in order to predict future changes with confidence.

Purification system

NASA Technical Reports Server (NTRS)

Flanagan, David T. (Inventor); Gibbons, Randall E. (Inventor)

1992-01-01

A system for prolonging the life of a granulated activated charcoal (GAC) water treatment device is disclosed in which an ultraviolet light transparent material is used to constrain water to flow over carbon surfaces. It is configured to receive maximum flux from a UV radiation source for the purpose of preventing microbial proliferation on the carbon surfaces; oxidizing organic contaminants adsorbed from the water onto the carbon surfaces and from biodegradation of adsorbed microbial forms; disinfecting water; and oxidizing organic contaminants in the water.

Optically Nonlinear Polymeric Materials.

DTIC Science & Technology

1983-01-01

distilled water . Polymer A was deposited onto two back-to-back clean glass slides on the upstroke. The subphase surface was cleaned and either behenic acid...having a water soluble head orouc I and a hydrophobic tail group such as a long chain fatty acid. The amphiphiles are spread on the water surface of a L/B...trough (Figure 1). The hydrophilic head group sits on . the water surface, while the hydrophobic alkyl tails orient themselves away from the water By

Coastal groundwater/surface-water interactions: a Great Lakes case study

USGS Publications Warehouse

Neff, Brian P.; Haack, Sheridan K.; Rosenberry, Donald O.; Savino, Jacqueline F.; Lundstrom, Scott C.

2006-01-01

Key similarities exist between marine and Great Lakes coastal environments. Water and nutrient fluxes across lakebeds in the Great Lakes are influenced by seiche and wind set-up and set-down, analogous to tidal influence in marine settings. Groundwater/surface-water interactions also commonly involve a saline-fresh water interface, although in the Great-Lakes cases, it is groundwater that is commonly saline and surface water that is fresh. Evapotranspiration also affects nearshore hydrology in both settings. Interactions between groundwater and surface water have recently been identified as an important component of ecological processes in the Great Lakes. Water withdrawals and the reversal of the groundwater/surface water seepage gradient are also common to many coastal areas around the Great Lakes. As compared to surface water, regional groundwater that discharges to western Lake Erie from Michigan is highly mineralized. Studies conducted by the U.S. Geological Survey at Erie State Game Area in southeastern Michigan, describe groundwater flow dynamics and chemistry, shallow lake-water chemistry, and fish and invertebrate communities. Results presented here provide an overview of recent progress of ongoing interdisciplinary studies of Great Lakes nearshore systems and describe a conceptual model that identifies relations among geologic, hydrologic, chemical, and biological processes in the coastal habitats of Lake Erie. This conceptual model is based on analysis of hydraulic head in piezometers at the study site and chemical analysis of deep and shallow coastal groundwater.

Extratropical Influence of Sea Surface Temperature and Wind on Water Recycling Rate Over Oceans and Coastal Lands

NASA Technical Reports Server (NTRS)

Hu, Hua; Liu, W. Timothy

1999-01-01

Water vapor and precipitation are two important parameters confining the hydrological cycle in the atmosphere and over the ocean surface. In the extratropical areas, due to variations of midlatitude storm tracks and subtropical jetstreams, water vapor and precipitation have large variability. Recently, a concept of water recycling rate defined previously by Chahine et al. (GEWEX NEWS, August, 1997) has drawn increasing attention. The recycling rate of moisture is calculated as the ratio of precipitation to total precipitable water (its inverse is the water residence time). In this paper, using multi-sensor spacebased measurements we will study the role of sea surface temperature and ocean surface wind in determining the water recycling rate over oceans and coastal lands. Response of water recycling rate in midlatitudes to the El Nino event will also be discussed. Sea surface temperature data are derived from satellite observations from the Advanced Very High Resolution Radiometer (AVHRR) blended with in situ measurements, available for the period 1982-1998. Global sea surface wind observations are obtained from spaceborne scatterometers aboard on the European Remote-Sensing Satellite (ERS1 and 2), available for the period 1991-1998. Global total precipitable water provided by the NASA Water Vapor Project (NVAP) is available for the period 1988-1995. Global monthly mean precipitation provided by the Global Precipitation Climatology Project (GPCP) is available for the period 1987-1998.

Enhancement of Water Evaporation on Solid Surfaces with Nanoscale Hydrophobic-Hydrophilic Patterns.

PubMed

Wan, Rongzheng; Wang, Chunlei; Lei, Xiaoling; Zhou, Guoquan; Fang, Haiping

2015-11-06

Using molecular dynamics simulations, we show that the evaporation of nanoscale water on hydrophobic-hydrophilic patterned surfaces is unexpectedly faster than that on any surfaces with uniform wettability. The key to this phenomenon is that, on the patterned surface, the evaporation rate from the hydrophilic region only slightly decreases due to the correspondingly increased water thickness; meanwhile, a considerable number of water molecules evaporate from the hydrophobic region despite the lack of water film. Most of the evaporated water from the hydrophobic region originates from the hydrophilic region by diffusing across the contact lines. Further analysis shows that the evaporation rate from the hydrophobic region is approximately proportional to the total length of the contact lines.

Ground-water and surface-water elevations in the Fairbanks International Airport area, Alaska, 1990-96, and selected geohydrologic report references

USGS Publications Warehouse

Claar, David V.; Lilly, Michael R.

1997-01-01

Ground-water and surface-water elevation data were collected at 61 sites from 1990 to 1996 by the U.S. Geological Survey in cooperation with the Alaska Department of Transportation and Public Facilities, Fairbanks International Airport. Water-surface elevations were measured in 41 ground-water observation wells and at 20 surface-water sites to help characterize the geohydrology of the Fairbanks International Airport area. From 1990 to 1993, data were collected in the vicinity of the former fire-training area at the airport. From 1993 to 1996, the data-collection area was expanded to include the entire airport area. The total number of data-collection sites varied each year because of changing project objectives and increased understanding of the geohydrology in the area.

Variation of Water Quality Parameters with Siltation Depth for River Ichamati Along International Border with Bangladesh Using Multivariate Statistical Techniques

NASA Astrophysics Data System (ADS)

Roy, P. K.; Pal, S.; Banerjee, G.; Biswas Roy, M.; Ray, D.; Majumder, A.

2014-12-01

River is considered as one of the main sources of freshwater all over the world. Hence analysis and maintenance of this water resource is globally considered a matter of major concern. This paper deals with the assessment of surface water quality of the Ichamati river using multivariate statistical techniques. Eight distinct surface water quality observation stations were located and samples were collected. For the samples collected statistical techniques were applied to the physico-chemical parameters and depth of siltation. In this paper cluster analysis is done to determine the relations between surface water quality and siltation depth of river Ichamati. Multiple regressions and mathematical equation modeling have been done to characterize surface water quality of Ichamati river on the basis of physico-chemical parameters. It was found that surface water quality of the downstream river was different from the water quality of the upstream. The analysis of the water quality parameters of the Ichamati river clearly indicate high pollution load on the river water which can be accounted to agricultural discharge, tidal effect and soil erosion. The results further reveal that with the increase in depth of siltation, water quality degraded.

Variable exchange between a stream and an aquifer in the Rio Grande Project Area

NASA Astrophysics Data System (ADS)

Sheng, Z.; Abudu, S.; Michelsen, A.; King, P.

2016-12-01

Both surface water and groundwater in the Rio Grande Project area in southern New Mexico and Far West Texas have been stressed by natural conditions such as droughts and human activities, including urban development and agricultural irrigation. In some area pumping stress in the aquifer becomes so great that it depletes the river flow especially during the irrigation season, typically from March through October. Therefore understanding such relationship between surface water and groundwater becomes more important in regional water resources planning and management. In this area, stream flows are highly regulated by the upstream reservoirs during the irrigation season and greatly influenced by return flows during non-irrigation season. During a drought additional groundwater pumping to supplement surface water shortage further complicates the surface water and groundwater interaction. In this paper the authors will use observation data and results of numerical models (MODFLOW) to characterize and quantify hydrological exchange fluxes between groundwater in the aquifers and surface water as well as impacts of groundwater pumping. The interaction shows a very interesting seasonal variation (irrigation vs. non-irrigation) as well as impact of a drought. Groundwater has been pumped for both municipal supplies and agricultural irrigation, which has imposed stresses toward both stream flows and aquifer storage. The results clearly show that historic groundwater pumping has caused some reaches of the river change from gaining stream to losing stream. Beyond the exchange between surface water and groundwater in the shallow aquifer, groundwater pumping in a deep aquifer could also enhance the exchanges between different aquifers through leaky confining layers. In the earlier history of pumping, pumping from the shallow aquifer is compensated by simple depletion of surface water, while deep aquifer tends to use the aquifer storage. With continued pumping, the cumulative stresses from deeper aquifers migrate upward, resulting in additional depletion of surface water. Eventually such impacts turn some reaches of a gaining river into a losing stream. The research finding provides information needed for future regional water planning and conjunctive management of surface water and groundwater resources.

Acetone and Water on TiO₂(110): H/D Exchange

DOE Office of Scientific and Technical Information (OSTI.GOV)

Henderson, Michael A.

2005-04-12

Isotopic H/D exchange between coadsorbed acetone and water on the TiO?(110) surface was examined using temperature programmed desorption (TPD) as a function of coverage and two surface pretreatments (oxidation and reduction). Coadsorbed acetone and water interact repulsively on reduced TiO?(110) based on results from the companion paper to this study, with water exerting a greater influence in destabilizing acetone and acetone having only a nominal influence on water. Despite the repulsive interaction between these coadsorbates, about 0.02 ML of a 1 ML d6-acetone on the reduced surface exhibits H/D exchange with coadsorbed water, with the exchange occurring exclusively in themore » high temperature region of the d?-acetone TPD spectrum at {approx}340 K. The effect was confirmed with combinations of d?-acetone and D?O. The extent of exchange decreased on the reduced surface with water coverages above {approx}0.3 ML due to the ability of water to displace coadsorbed acetone from first layer sites to the multilayer. In contrast, the extent of exchange increased by a factor of 3 when the surface was pre-oxidized prior to coadsorption. In this case, there was no evidence for the negative influence of high water coverages on the extent of H/D exchange. Comparison of the TPD spectra from the exchange products (either d?- or d?-acetone depending on the coadsorption pairing) suggests that, in addition to the 340 K exchange process seen on the reduced surface, a second exchange process was observed on the oxidized surface at {approx}390 K. In both cases (oxidized and reduced), desorption of the H/D exchange products appeared to be reaction limited and to involve the influence of OH/OD groups (or water formed during recombinative desorption of OH/OD groups) instead of molecularly adsorbed water. The 340 K exchange process is assigned to reaction at step sites and the 390 K exchange process is attributed to the influence of oxygen adatoms deposited during surface oxidation. The H/D exchange mechanism likely involves an enolate or propenol surface intermediate formed transiently during the desorption of oxygen-stabilized acetone molecules.« less

Endmembers of Ice Shelf Melt

NASA Astrophysics Data System (ADS)

Boghosian, A.; Child, S. F.; Kingslake, J.; Tedesco, M.; Bell, R. E.; Alexandrov, O.; McMichael, S.

2017-12-01

Studies of surface melt on ice shelves have defined a spectrum of meltwater behavior. On one end the storage of meltwater in persistent surface ponds can trigger ice shelf collapse as in the 2002 event leading to the disintegration of the Larsen B Ice Shelf. On the other, meltwater export by rivers can stabilize an ice shelf as was recently shown on the Nansen Ice Shelf. We explore this dichotomy by quantifying the partitioning between stored and transported water on two glaciers adjacent to floating ice shelves, Nimrod (Antarctica) and Peterman (Greenland). We analyze optical satellite imagery (LANDSAT, WorldView), airborne imagery (Operation IceBridge, Trimetrogon Aerial Phototography), satellite radar (Sentinel-1), and digital elevation models (DEMs) to categorize surface meltwater fate and map the evolution of ice shelf hydrology and topographic features through time. On the floating Peterman Glacier tongue a sizable river exports water to the ocean. The surface hydrology of Nimrod Glacier, geometrically similar to Peterman but with ten times shallower surface slope, is dominated by storage in surface lakes. In contrast, the Nansen has the same surface slope as Nimrod but transports water through surface rivers. Slope alone is not the sole control on ice shelf hydrology. It is essential to track the storage and transport volumes for each of these systems. To estimate water storage and transport we analyze high resolution (40 cm - 2 m) modern and historical DEMs. We produce historical (1957 onwards) DEMs with structure-from-motion photogrammetry. The DEMs are used to constrain water storage potential estimates of observed basins and water routing/transport potential. We quantify the total volume of water stored seasonally and interannually. We use the normalize difference water index to map meltwater extent, and estimate lake water depth from optical data. We also consider the role of stored water in subsurface aquifers in recharging surface water after observing a pond and river reemerge after apparently freezing during the 2016-17 melt season. Using the ponds/rivers endmember scheme helps us to constrain the role storage and transport play on stabilizing ice shelves. By extending this analysis to other ice tongues and shelves we can better understand their vulnerability to a warming world.

Investigating surface water-well interaction using stable isotope ratios of water

USGS Publications Warehouse

Hunt, R.J.; Coplen, T.B.; Haas, N.L.; Saad, D.A.; Borchardt, M. A.

2005-01-01

Because surface water can be a source of undesirable water quality in a drinking water well, an understanding of the amount of surface water and its travel time to the well is needed to assess a well's vulnerability. Stable isotope ratios of oxygen in river water at the City of La Crosse, Wisconsin, show peak-to-peak seasonal variation greater than 4??? in 2001 and 2002. This seasonal signal was identified in 7 of 13 city municipal wells, indicating that these 7 wells have appreciable surface water contributions and are potentially vulnerable to contaminants in the surface water. When looking at wells with more than 6 sampling events, a larger variation in ??18O compositions correlated with a larger fraction of surface water, suggesting that samples collected for oxygen isotopic composition over time may be useful for identifying the vulnerability to surface water influence even if a local meteoric water line is not available. A time series of ??18O from one of the municipal wells and from a piezometer located between the river and the municipal well showed that the travel time of flood water to the municipal well was approximately 2 months; non-flood arrival times were on the order of 9 months. Four independent methods were also used to assess time of travel. Three methods (groundwater temperature arrival times at the intermediate piezometer, virus-culture results, and particle tracking using a numerical groundwater-flow model) yielded flood and non-flood travel times of less than 1 year for this site. Age dating of one groundwater sample using 3H-3He methods estimated an age longer than 1 year, but was likely confounded by deviations from piston flow as noted by others. Chlorofluorocarbons and SF6 analyses were not useful at this site due to degradation and contamination, respectively. This work illustrates the utility of stable hydrogen and oxygen isotope ratios of water to determine the contribution and travel time of surface water in groundwater, and demonstrates the importance of using multiple methods to improve estimates for time of travel of 1 year or less. ?? 2004 Elsevier B.V. All rights reserved.

Experimental observation of standing interfacial waves induced by surface waves in muddy water

NASA Astrophysics Data System (ADS)

Maxeiner, Eric; Dalrymple, Robert A.

2011-09-01

A striking feature has been observed in a laboratory wave tank with a thin layer of clear water overlying a layer of mud. A piston-type wave maker is used to generate long monochromatic surface waves in a tank with a layer of kaolinite clay at the bottom. The wave action on the mud causes the clay particles to rise from the bottom into the water column, forming a lutocline. As the lutocline approaches the water surface, a set of standing interfacial waves form on the lutocline. The interfacial wave directions are oriented nearly orthogonal to the surface wave direction. The interfacial waves, which sometimes cover the entire length and width of the tank, are also temporally subharmonic as the phase of the interfacial wave alternates with each passing surface wave crest. These interfacial waves are the result of a resonant three-wave interaction involving the surface wave train and the two interfacial wave trains. The interfacial waves are only present when the lutocline is about 3 cm of the water surface and they can be sufficiently nonlinear as to exhibit superharmonics and a breaking-type of instability.

Impact of land cover change on the environmental hydrology characteristics in Kelantan river basin, Malaysia

NASA Astrophysics Data System (ADS)

Saadatkhah, Nader; Mansor, Shattri; Khuzaimah, Zailani; Asmat, Arnis; Adnan, Noraizam; Adam, Siti Noradzah

2016-09-01

Changing the land cover/ land use has serious environmental impacts affecting the ecosystem in Malaysia. The impact of land cover changes on the environmental functions such as surface water, loss water, and soil moisture is considered in this paper on the Kelantan river basin. The study area at the east coast of the peninsular Malaysia has suffered significant land cover changes in the recent years. The current research tried to assess the impact of land cover changes in the study area focused on the surface water, loss water, and soil moisture from different land use classes and the potential impact of land cover changes on the ecosystem of Kelantan river basin. To simulate the impact of land cover changes on the environmental hydrology characteristics, a deterministic regional modeling were employed in this study based on five approaches, i.e. (1) Land cover classification based on Landsat images; (2) assessment of land cover changes during last three decades; (3) Calculation the rate of water Loss/ Infiltration; (4) Assessment of hydrological and mechanical effects of the land cover changes on the surface water; and (5) evaluation the impact of land cover changes on the ecosystem of the study area. Assessment of land cover impact on the environmental hydrology was computed with the improved transient rainfall infiltration and grid based regional model (Improved-TRIGRS) based on the transient infiltration, and subsequently changes in the surface water, due to precipitation events. The results showed the direct increased in surface water from development area, agricultural area, and grassland regions compared with surface water from other land covered areas in the study area. The urban areas or lower planting density areas tend to increase for surface water during the monsoon seasons, whereas the inter flow from forested and secondary jungle areas contributes to the normal surface water.

Surface-Water to Groundwater Transport of Pharmaceuticals in a Wastewater-Impacted Stream in the U.S.

NASA Astrophysics Data System (ADS)

Bradley, P. M.; Barber, L. B.; Duris, J. W.; Foreman, W. T.; Furlong, E. T.; Hubbard, L. E.; Hutchinson, K. J.; Keefe, S. H.; Kolpin, D. W.

2014-12-01

Wastewater pharmaceutical contamination of shallow groundwater is a substantial concern in effluent-dominated streams, due to aqueous mobility and designed bioactivity of pharmaceuticals and due to effluent-driven hydraulic gradients. Improved understanding of the environmental fate and transport of wastewater-derived pharmaceuticals is essential for effective protection of vital aquatic ecosystem services, environmental health, and drinking-water supplies. Substantial longitudinal (downstream) transport of pharmaceutical contaminants has been documented in effluent-impacted streams. The comparative lack of information on vertical and lateral transport (infiltration) of wastewater contaminants from surface-water to hyporheic and shallow groundwater compartments is a critical scientific data gap, given the potential for contamination of groundwater supplies in effluent-impacted systems. Growing dependencies on bank filtration and artificial recharge applications for release of wastewater to the environment and for pretreatment of poor-quality surface-water for drinking water emphasize the critical need to better understand the exchange of wastewater contaminants, like pharmaceuticals, between surface-water and groundwater compartments. The potential transport of effluent-derived pharmaceutical contaminants from surface-water to hyporheic-water and shallow groundwater compartments was examined in a wastewater-treatment-facility (WWTF) impacted stream in Ankeny, Iowa under effluent-dominated (71-99% of downstream flow) conditions. Strong hydraulic gradients and hydrologic connectivity were evident between surface-water and shallow-groundwater compartments in the vicinity of the WWTF outfall. Carbamazepine, sulfamethoxazole, and immunologically-related compounds were detected in groundwater 10-20 meters from the stream bank. Direct aqueous-injection HPLC-MS/MS revealed high percentage detections of pharmaceuticals (110 total analytes) in surface-water and groundwater samples. The results demonstrate the importance of effluent discharge as a driver of local hydrologic conditions in an effluent-impacted stream and thus as a fundamental control on surface-water to groundwater transport of effluent-derived pharmaceutical contaminants.

Novel Methodology for the Highly-Efficient Separation of Oil and Water (Briefing Charts)

DTIC Science & Technology

2014-03-16

2DISTRIBUTION A. Approved for public release; distribution unlimited. Non-wetting surfaces Superhydrophilic Hydrophilic Hydrophobic Superhydrophobic ...concentrations many surfaces are both superhydrophobic and superoleophilic (*alkane ≈ 0°). Thus, these porous surfaces form ideal membranes for separating...Fluorodecyl POSS Advancing - Water Receding - Water Advancing - Octane Receding - Octane Superhydrophobic Superoleophilic Superhydrophobic

18 CFR 806.4 - Projects requiring review and approval.

Code of Federal Regulations, 2012 CFR

2012-04-01

... groundwater or surface water, shall also be subject to the standards set forth in § 806.23. Except to the... average of 100,000 gpd or more from a groundwater or surface water source, or a combination of such... which involves a withdrawal from a groundwater or surface water source and which is subject to the...

18 CFR 806.4 - Projects requiring review and approval.

Code of Federal Regulations, 2013 CFR

2013-04-01

... groundwater or surface water, shall also be subject to the standards set forth in § 806.23. Except to the... average of 100,000 gpd or more from a groundwater or surface water source, or a combination of such... which involves a withdrawal from a groundwater or surface water source and which is subject to the...