Sample records for highly ordered water

  1. An adaptive multiblock high-order finite-volume method for solving the shallow-water equations on the sphere

    DOE PAGES

    McCorquodale, Peter; Ullrich, Paul; Johansen, Hans; ...

    2015-09-04

    We present a high-order finite-volume approach for solving the shallow-water equations on the sphere, using multiblock grids on the cubed-sphere. This approach combines a Runge--Kutta time discretization with a fourth-order accurate spatial discretization, and includes adaptive mesh refinement and refinement in time. Results of tests show fourth-order convergence for the shallow-water equations as well as for advection in a highly deformational flow. Hierarchical adaptive mesh refinement allows solution error to be achieved that is comparable to that obtained with uniform resolution of the most refined level of the hierarchy, but with many fewer operations.

  2. Prediction of Ordered Water Molecules in Protein Binding Sites from Molecular Dynamics Simulations: The Impact of Ligand Binding on Hydration Networks.

    PubMed

    Rudling, Axel; Orro, Adolfo; Carlsson, Jens

    2018-02-26

    Water plays a major role in ligand binding and is attracting increasing attention in structure-based drug design. Water molecules can make large contributions to binding affinity by bridging protein-ligand interactions or by being displaced upon complex formation, but these phenomena are challenging to model at the molecular level. Herein, networks of ordered water molecules in protein binding sites were analyzed by clustering of molecular dynamics (MD) simulation trajectories. Locations of ordered waters (hydration sites) were first identified from simulations of high resolution crystal structures of 13 protein-ligand complexes. The MD-derived hydration sites reproduced 73% of the binding site water molecules observed in the crystal structures. If the simulations were repeated without the cocrystallized ligands, a majority (58%) of the crystal waters in the binding sites were still predicted. In addition, comparison of the hydration sites obtained from simulations carried out in the absence of ligands to those identified for the complexes revealed that the networks of ordered water molecules were preserved to a large extent, suggesting that the locations of waters in a protein-ligand interface are mainly dictated by the protein. Analysis of >1000 crystal structures showed that hydration sites bridged protein-ligand interactions in complexes with different ligands, and those with high MD-derived occupancies were more likely to correspond to experimentally observed ordered water molecules. The results demonstrate that ordered water molecules relevant for modeling of protein-ligand complexes can be identified from MD simulations. Our findings could contribute to development of improved methods for structure-based virtual screening and lead optimization.

  3. Chloride ions induce order-disorder transition at water-oxide interfaces

    NASA Astrophysics Data System (ADS)

    Deshmukh, Sanket; Kamath, Ganesh; Ramanathan, Shriram; Sankaranarayanan, Subramanian K. R. S.

    2013-12-01

    Water can form quasi-two-dimensional ordered layers near a solid interface. The solvation dynamics and ionic transport phenomena through this ordered water structure is of direct relevance to a variety of problems in interface science. Molecular dynamics simulations are used to study the impact of local fluctuation of the chloride ion density in the vicinity of an oxide surface on the structure and dynamics of water layers. We demonstrate that local increase in chloride ions beyond a threshold concentration near the water-MgO (100) interface introduces an order-disorder transition of this two-dimensional layered network into bulklike water, leading to increased diffusional characteristics and reduced hydrogen bonding lifetimes. We find that the extent of this order-disorder transition can be tuned by modifying the defect chemistry and nature of the underlying substrate. The kinetic fluidity resulting from order-disorder transition at high chloride ion concentration has significance for a broad range of phenomena, ranging from freezing point depression of brine to onset of aqueous corrosion.

  4. Well-balanced high-order centered schemes on unstructured meshes for shallow water equations with fixed and mobile bed

    NASA Astrophysics Data System (ADS)

    Canestrelli, Alberto; Dumbser, Michael; Siviglia, Annunziato; Toro, Eleuterio F.

    2010-03-01

    In this paper, we study the numerical approximation of the two-dimensional morphodynamic model governed by the shallow water equations and bed-load transport following a coupled solution strategy. The resulting system of governing equations contains non-conservative products and it is solved simultaneously within each time step. The numerical solution is obtained using a new high-order accurate centered scheme of the finite volume type on unstructured meshes, which is an extension of the one-dimensional PRICE-C scheme recently proposed in Canestrelli et al. (2009) [5]. The resulting first-order accurate centered method is then extended to high order of accuracy in space via a high order WENO reconstruction technique and in time via a local continuous space-time Galerkin predictor method. The scheme is applied to the shallow water equations and the well-balanced properties of the method are investigated. Finally, we apply the new scheme to different test cases with both fixed and movable bed. An attractive future of the proposed method is that it is particularly suitable for engineering applications since it allows practitioners to adopt the most suitable sediment transport formula which better fits the field data.

  5. Molecular dynamics simulations of proton-ordered water confined in low-diameter carbon nanotubes.

    PubMed

    Li, Shujuan; Schmidt, Burkhard

    2015-03-21

    The present work deals with molecular dynamics simulations of water confined in single-walled carbon nanotubes (CNTs), with emphasis on the proton-ordering of water and its polarization. First, the water occupancy of open-ended armchair and zigzag CNTs immersed in water under ambient NPT conditions is calculated for various water models, and for varying Lennard-Jones parameters of the water-carbon interaction. As a function of the CNT diameter, the water density displays several oscillations before converging to the bulk value. Based on these results, the water structures encapsulated in 10 nm long armchair CNTs (n,n) with 5 ≤ n ≤ 10, are investigated under NVT conditions. Inside the smallest nanotubes (n = 5, 6) highly ferroelectric (FE), quasi-one-dimensional water chains are found while inside the other CNTs water molecules assemble into single-walled ice nanotubes (INTs). There are several, near-degenerate minimum energy INT structures: single helical structures were found for 7 ≤ n ≤ 10, in all cases in FE arrangement. In addition, a double helical INT structure was found for n = 8 with an even higher polarization. Prism-like structures were found only for 8 ≤ n ≤ 10 with various FE, ferrielectric (FI), and antiferroelectric (AF, n = 9, 10) proton ordering. The coexistence of the nearly iso-energetic FE, FI, and AF INT structures separated by high barriers renders the molecular dynamics highly metastable, typically with nanosecond timescales at room temperature. Hence, the replica exchange simulation method is used to obtain populations of different INT states at finite temperatures. Many of the FE INT structures confined in low-diameter CNTs are still prevalent at room temperature. Both helix-helix and helix-prism structural transitions are detected which can be either continuous (around 470 K for n = 8) or discontinuous (at 218 K for n = 9). Also melting-like transitions are found in which the INT structures are disrupted leading to a loss of FE or FI ordering of the water orientations. Also these transitions can be either smooth (for n = 7, 8) or abrupt, first-order transitions, at T = 362 K for n = 9 and at T = 285 K for n = 10.

  6. Nucleation processes of nanobubbles at a solid/water interface

    NASA Astrophysics Data System (ADS)

    Fang, Chung-Kai; Ko, Hsien-Chen; Yang, Chih-Wen; Lu, Yi-Hsien; Hwang, Ing-Shouh

    2016-04-01

    Experimental investigations of hydrophobic/water interfaces often return controversial results, possibly due to the unknown role of gas accumulation at the interfaces. Here, during advanced atomic force microscopy of the initial evolution of gas-containing structures at a highly ordered pyrolytic graphite/water interface, a fluid phase first appeared as a circular wetting layer ~0.3 nm in thickness and was later transformed into a cap-shaped nanostructure (an interfacial nanobubble). Two-dimensional ordered domains were nucleated and grew over time outside or at the perimeter of the fluid regions, eventually confining growth of the fluid regions to the vertical direction. We determined that interfacial nanobubbles and fluid layers have very similar mechanical properties, suggesting low interfacial tension with water and a liquid-like nature, explaining their high stability and their roles in boundary slip and bubble nucleation. These ordered domains may be the interfacial hydrophilic gas hydrates and/or the long-sought chemical surface heterogeneities responsible for contact line pinning and contact angle hysteresis. The gradual nucleation and growth of hydrophilic ordered domains renders the original homogeneous hydrophobic/water interface more heterogeneous over time, which would have great consequence for interfacial properties that affect diverse phenomena, including interactions in water, chemical reactions, and the self-assembly and function of biological molecules.

  7. High-definition polymeric membranes: construction of 3D lithographed channel arrays through control of natural building blocks dynamics.

    PubMed

    Speranza, Valentina; Trotta, Francesco; Drioli, Enrico; Gugliuzza, Annarosa

    2010-02-01

    The fabrication of well-defined interfaces is in high demand in many fields of biotechnologies. Here, high-definition membrane-like arrays are developed through the self-assembly of water droplets, which work as natural building blocks for the construction of ordered channels. Solution viscosity together with the dynamics of the water droplets can decide the final formation of three-dimensional well-ordered patterns resembling anodic structures, especially because solvents denser than water are used. Particularly, the polymer solution viscosity is demonstrated to be a powerful tool for control of the mobility of submerged droplets during the microfabrication process. The polymeric patterns are structured at very high levels of organization and exhibit well-established transport-surface property relationships, considered basics for any types of advanced biotechnologies.

  8. Extending High-Order Flux Operators on Spherical Icosahedral Grids and Their Applications in the Framework of a Shallow Water Model

    NASA Astrophysics Data System (ADS)

    Zhang, Yi

    2018-01-01

    This study extends a set of unstructured third/fourth-order flux operators on spherical icosahedral grids from two perspectives. First, the fifth-order and sixth-order flux operators of this kind are further extended, and the nominally second-order to sixth-order operators are then compared based on the solid body rotation and deformational flow tests. Results show that increasing the nominal order generally leads to smaller absolute errors. Overall, the standard fifth-order scheme generates the smallest errors in limited and unlimited tests, although it does not enhance the convergence rate. Even-order operators show higher limiter sensitivity than the odd-order operators. Second, a triangular version of these high-order operators is repurposed for transporting the potential vorticity in a space-time-split shallow water framework. Results show that a class of nominally third-order upwind-biased operators generates better results than second-order and fourth-order counterparts. The increase of the potential enstrophy over time is suppressed owing to the damping effect. The grid-scale noise in the vorticity is largely alleviated, and the total energy remains conserved. Moreover, models using high-order operators show smaller numerical errors in the vorticity field because of a more accurate representation of the nonlinear Coriolis term. This improvement is especially evident in the Rossby-Haurwitz wave test, in which the fluid is highly rotating. Overall, high-order flux operators with higher damping coefficients, which essentially behave like the Anticipated Potential Vorticity Method, present better results.

  9. Microscopic structural descriptor of liquid water

    NASA Astrophysics Data System (ADS)

    Shi, Rui; Tanaka, Hajime

    2018-03-01

    The microscopic structure of liquid water has been believed to be the key to the understanding of the unique properties of this extremely important substance. Many structural descriptors have been developed for revealing local structural order in water, but their properties are still not well understood. The essential difficulty comes from structural fluctuations due to thermal noise, which are intrinsic to the liquid state. The most popular and widely used descriptors are the local structure index (LSI) and d5. Recently, Russo and Tanaka [Nat. Commun. 3, 3556 (2014)] introduced a new descriptor ζ which measures the translational order between the first and second shells considering hydrogen bonding (H-bonding) in the first shell. In this work, we compare the performance of these three structural descriptors for a popular water model known as TIP5P water. We show that local structural ordering can be properly captured only by the structural descriptor ζ, but not by the other two descriptors particularly at a high temperature, where thermal noise effects are severe. The key difference of ζ from LSI and d5 is that only ζ considers H-bonding which is crucial to detect high translational and tetrahedral order of not only oxygen but also hydrogen atoms. The importance of H-bonding is very natural, considering the fact that the locally favored structures are stabilized by energy gain due to the formation of four hydrogen bonds between the central water molecule and its neighboring ones in the first shell. Our analysis of the water structure by using ζ strongly supports the two-state model of water: water is a dynamic mixture of locally favored (ordered) and normal-liquid (disordered) structures. This work demonstrates the importance of H-bonding in the characterization of water's structures and provides a useful structural descriptor for water-type tetrahedral liquids to study their structure and dynamics.

  10. High-Performance Integrated Control of water quality and quantity in urban water reservoirs

    NASA Astrophysics Data System (ADS)

    Galelli, S.; Castelletti, A.; Goedbloed, A.

    2015-11-01

    This paper contributes a novel High-Performance Integrated Control framework to support the real-time operation of urban water supply storages affected by water quality problems. We use a 3-D, high-fidelity simulation model to predict the main water quality dynamics and inform a real-time controller based on Model Predictive Control. The integration of the simulation model into the control scheme is performed by a model reduction process that identifies a low-order, dynamic emulator running 4 orders of magnitude faster. The model reduction, which relies on a semiautomatic procedural approach integrating time series clustering and variable selection algorithms, generates a compact and physically meaningful emulator that can be coupled with the controller. The framework is used to design the hourly operation of Marina Reservoir, a 3.2 Mm3 storm-water-fed reservoir located in the center of Singapore, operated for drinking water supply and flood control. Because of its recent formation from a former estuary, the reservoir suffers from high salinity levels, whose behavior is modeled with Delft3D-FLOW. Results show that our control framework reduces the minimum salinity levels by nearly 40% and cuts the average annual deficit of drinking water supply by about 2 times the active storage of the reservoir (about 4% of the total annual demand).

  11. Nonequilibrium Phase Transitions in Supercooled Water

    NASA Astrophysics Data System (ADS)

    Limmer, David; Chandler, David

    2012-02-01

    We present results of a simulation study of water driven out of equilibrium. Using transition path sampling, we can probe stationary path distributions parameterize by order parameters that are extensive in space and time. We find that by coupling external fields to these parameters, we can drive water through a first order dynamical phase transition into amorphous ice. By varying the initial equilibrium distributions we can probe pathways for the creation of amorphous ices of low and high densities.

  12. Soliton, rational, and periodic solutions for the infinite hierarchy of defocusing nonlinear Schrödinger equations.

    PubMed

    Ankiewicz, Adrian

    2016-07-01

    Analysis of short-pulse propagation in positive dispersion media, e.g., in optical fibers and in shallow water, requires assorted high-order derivative terms. We present an infinite-order "dark" hierarchy of equations, starting from the basic defocusing nonlinear Schrödinger equation. We present generalized soliton solutions, plane-wave solutions, and periodic solutions of all orders. We find that "even"-order equations in the set affect phase and "stretching factors" in the solutions, while "odd"-order equations affect the velocities. Hence odd-order equation solutions can be real functions, while even-order equation solutions are complex. There are various applications in optics and water waves.

  13. Sediment yield along an actively managed riparian buffer

    Treesearch

    Ferhat Kara; Edward F. Loewenstein; Latif Kalin

    2012-01-01

    High quality water is generally associated with forested watersheds. However, intensive forestry activities within these watersheds can negatively affect water quality. In order to mitigate negative effects of forestry operations on water quality, best management practices (BMPs) are recommended. In this study, effects of silvicultural treatments on water quality are...

  14. Selecting an optimal number of binding site waters to improve virtual screening enrichments against the adenosine A2A receptor.

    PubMed

    Lenselink, Eelke B; Beuming, Thijs; Sherman, Woody; van Vlijmen, Herman W T; IJzerman, Adriaan P

    2014-06-23

    A major challenge in structure-based virtual screening (VS) involves the treatment of explicit water molecules during docking in order to improve the enrichment of active compounds over decoys. Here we have investigated this in the context of the adenosine A2A receptor, where water molecules have previously been shown to be important for achieving high enrichment rates with docking, and where the positions of some binding site waters are known from a high-resolution crystal structure. The effect of these waters (both their presence and orientations) on VS enrichment was assessed using a carefully curated set of 299 high affinity A2A antagonists and 17,337 decoys. We show that including certain crystal waters greatly improves VS enrichment and that optimization of water hydrogen positions is needed in order to achieve the best results. We also show that waters derived from a molecular dynamics simulation - without any knowledge of crystallographic waters - can improve enrichments to a similar degree as the crystallographic waters, which makes this strategy applicable to structures without experimental knowledge of water positions. Finally, we used decision trees to select an ensemble of structures with different water molecule positions and orientations that outperforms any single structure with water molecules. The approach presented here is validated against independent test sets of A2A receptor antagonists and decoys from the literature. In general, this water optimization strategy could be applied to any target with waters-mediated protein-ligand interactions.

  15. Extension of the TRANSURANUS burnup model to heavy water reactor conditions

    NASA Astrophysics Data System (ADS)

    Lassmann, K.; Walker, C. T.; van de Laar, J.

    1998-06-01

    The extension of the light water reactor burnup equations of the TRANSURANUS code to heavy water reactor conditions is described. Existing models for the fission of 235U and the buildup of plutonium in a heavy water reactor are evaluated. In order to overcome the limitations of the frequently used RADAR model at high burnup, a new model is presented. After verification against data for the radial distributions of Xe, Cs, Nd and Pu from electron probe microanalysis, the model is used to analyse the formation of the high burnup structure in a heavy water reactor. The new model allows the analysis of light water reactor fuel rod designs at high burnup in the OECD Halden Heavy Water Reactor.

  16. High pressure cosmochemistry of major planetary interiors: Laboratory studies of the water-rich region of the system ammonia-water

    NASA Technical Reports Server (NTRS)

    Nicol, Malcolm; Johnson, Mary; Boone, Steven; Cynn, Hyunchee

    1987-01-01

    Several studies relative to high pressure cosmochemistry of major planetary interiors are summarized. The behavior of gas-ice mixtures at very high pressures, studies of the phase diagram of (NH3) sub x (H2O) sub 1-x at pressures to 5GPa and temperatures from 240 to 370 K, single crystal growth of ammonia dihydrate at room temperature in order to determine their structures by x-ray diffraction, spectroscopy of chemical reactions during shock compression in order to evaluate how the reactions affect the interpretation of equation of state data obtained by shock methods, and temperature and x-ray diffraction measurements made on resistively heated wire in diamond anvil cells in order to obtain phase and structural data relevant to the interiors of terrestrial planets are among the studies discussed.

  17. Ordered water structure at hydrophobic graphite interfaces observed by 4D, ultrafast electron crystallography

    PubMed Central

    Yang, Ding-Shyue; Zewail, Ahmed H.

    2009-01-01

    Interfacial water has unique properties in various functions. Here, using 4-dimensional (4D), ultrafast electron crystallography with atomic-scale spatial and temporal resolution, we report study of structure and dynamics of interfacial water assembly on a hydrophobic surface. Structurally, vertically stacked bilayers on highly oriented pyrolytic graphite surface were determined to be ordered, contrary to the expectation that the strong hydrogen bonding of water on hydrophobic surfaces would dominate with suppressed interfacial order. Because of its terrace morphology, graphite plays the role of a template. The dynamics is also surprising. After the excitation of graphite by an ultrafast infrared pulse, the interfacial ice structure undergoes nonequilibrium “phase transformation” identified in the hydrogen-bond network through the observation of structural isosbestic point. We provide the time scales involved, the nature of ice-graphite structural dynamics, and relevance to properties related to confined water. PMID:19246378

  18. Comparative genotoxicity of nitrosamine drinking water disinfection byproducts in Salmonella and mammalian cells.

    PubMed

    Wagner, Elizabeth D; Hsu, Kang-Mei; Lagunas, Angelica; Mitch, William A; Plewa, Michael J

    2012-01-24

    Nitrosamine water disinfection byproducts (DBPs) are an emerging class of non-halogenated, nitrogen-containing water contaminants. Five nitrosamine DBPs were analyzed for genotoxicity (N-nitrosodimethylamine (NDMA), N-nitrosopiperidine (NPIP), N-nitrosopyrrolidine (NPYR), N-nitrosomorpholine (NMOR) and N-nitrosodiphenylamine (NDPhA). Using Salmonella typhimurium strain YG7108 the descending rank order of mutagenicity was NDMA>NPIP>NMOR>NPYR; NDPhA was not mutagenic. We developed and calibrated an exogenous S9 mix that was highly effective in activating NDMA in Chinese hamster ovary (CHO) cells using the SCGE (Comet) assay. The descending rank order for genotoxicity was NDMA>NPIP>NMOR. NDPhA was genotoxic only at one concentration and NPYR was not genotoxic. The genotoxic potencies in S. typhimurium and CHO cells were highly correlated. Based on their comparative genotoxicity attention should be focused on the generation and occurrence of NDMA, NPIP and NMOR. Current drinking water disinfection processes may need to be modified such that the generation of nitrosamine DBPs is effectively limited in order to protect the environment and the public health. © 2011 Elsevier B.V. All rights reserved.

  19. Continuous flow synthesis of ZSM-5 zeolite on the order of seconds

    PubMed Central

    Liu, Zhendong; Okabe, Kotatsu; Anand, Chokkalingam; Yonezawa, Yasuo; Zhu, Jie; Yamada, Hiroki; Endo, Akira; Yanaba, Yutaka; Yoshikawa, Takeshi; Ohara, Koji; Okubo, Tatsuya; Wakihara, Toru

    2016-01-01

    The hydrothermal synthesis of zeolites carried out in batch reactors takes a time so long (typically, on the order of days) that the crystallization of zeolites has long been believed to be very slow in nature. We herein present a synthetic process for ZSM-5, an industrially important zeolite, on the order of seconds in a continuous flow reactor using pressurized hot water as a heating medium. Direct mixing of a well-tuned precursor (90 °C) with the pressurized water preheated to extremely high temperature (370 °C) in the millimeter-sized continuous flow reactor resulted in immediate heating to high temperatures (240–300 °C); consequently, the crystallization of ZSM-5 in a seed-free system proceeded to completion within tens of or even several seconds. These results indicate that the crystallization of zeolites can complete in a period on the order of seconds. The subtle design combining a continuous flow reactor with pressurized hot water can greatly facilitate the mass production of zeolites in the future. PMID:27911823

  20. Modification of 2-D Time-Domain Shallow Water Wave Equation using Asymptotic Expansion Method

    NASA Astrophysics Data System (ADS)

    Khairuman, Teuku; Nasruddin, MN; Tulus; Ramli, Marwan

    2018-01-01

    Generally, research on the tsunami wave propagation model can be conducted by using a linear model of shallow water theory, where a non-linear side on high order is ignored. In line with research on the investigation of the tsunami waves, the Boussinesq equation model underwent a change aimed to obtain an improved quality of the dispersion relation and non-linearity by increasing the order to be higher. To solve non-linear sides at high order is used a asymptotic expansion method. This method can be used to solve non linear partial differential equations. In the present work, we found that this method needs much computational time and memory with the increase of the number of elements.

  1. Extending high-order flux operators on spherical icosahedral grids and their application in a Shallow Water Model for transporting the Potential Vorticity

    NASA Astrophysics Data System (ADS)

    Zhang, Y.

    2017-12-01

    The unstructured formulation of the third/fourth-order flux operators used by the Advanced Research WRF is extended twofold on spherical icosahedral grids. First, the fifth- and sixth-order flux operators of WRF are further extended, and the nominally second- to sixth-order operators are then compared based on the solid body rotation and deformational flow tests. Results show that increasing the nominal order generally leads to smaller absolute errors. Overall, the fifth-order scheme generates the smallest errors in limited and unlimited tests, although it does not enhance the convergence rate. The fifth-order scheme also exhibits smaller sensitivity to the damping coefficient than the third-order scheme. Overall, the even-order schemes have higher limiter sensitivity than the odd-order schemes. Second, a triangular version of these high-order operators is repurposed for transporting the potential vorticity in a space-time-split shallow water framework. Results show that a class of nominally third-order upwind-biased operators generates better results than second- and fourth-order counterparts. The increase of the potential enstrophy over time is suppressed owing to the damping effect. The grid-scale noise in the vorticity is largely alleviated, and the total energy remains conserved. Moreover, models using high-order operators show smaller numerical errors in the vorticity field because of a more accurate representation of the nonlinear Coriolis term. This improvement is especially evident in the Rossby-Haurwitz wave test, in which the fluid is highly rotating. Overall, flux operators with higher damping coefficients, which essentially behaves like the Anticipated Potential Vorticity Method, present optimal results.

  2. Documentation of the Goddard Laboratory for atmospheres fourth-order two-layer shallow water model

    NASA Technical Reports Server (NTRS)

    Takacs, L. L. (Compiler)

    1986-01-01

    The theory and numerical treatment used in the 2-level GLA fourth-order shallow water model are described. This model was designed to emulate the horizontal finite differences used by the GLA Fourth-Order General Circulation Model (Kalnay et al., 1983) in addition to its grid structure, form of high-latitude and global filtering, and time-integration schemes. A user's guide is also provided instructing the user on how to create initial conditions, execute the model, and post-process the data history.

  3. Water quantity and quality model for the evaluation of water-management strategies in the Netherlands: application to the province of Friesland

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

    Brinkman, J.J.; Griffioen, P.S.; Groot, S.

    1987-03-01

    The Netherlands have a rather complex water-management system consisting of a number of major rivers, canals, lakes and ditches. Water-quantity management on a regional scale is necessary for an effective water-quality policy. To support water management, a computer model was developed that includes both water quality and water quantity, based on three submodels: ABOPOL for the water movement, DELWAQ for the calculation of water quality variables and BLOOM-II for the phytoplankton growth. The northern province of Friesland was chosen as a test case for the integrated model to be developed, where water quality is highly related to the water distributionmore » and the main trade-off is minimizing the intake of (eutrophicated) alien water in order to minimize external nutrient load and maximizing the intake in order to flush channels and lakes. The results of the application of these models to this and to a number of hypothetical future situations are described.« less

  4. Highly permeable artificial water channels that can self-assemble into two-dimensional arrays

    PubMed Central

    Shen, Yue-xiao; Si, Wen; Erbakan, Mustafa; Decker, Karl; De Zorzi, Rita; Saboe, Patrick O.; Kang, You Jung; Majd, Sheereen; Butler, Peter J.; Walz, Thomas; Aksimentiev, Aleksei; Hou, Jun-li; Kumar, Manish

    2015-01-01

    Bioinspired artificial water channels aim to combine the high permeability and selectivity of biological aquaporin (AQP) water channels with chemical stability. Here, we carefully characterized a class of artificial water channels, peptide-appended pillar[5]arenes (PAPs). The average single-channel osmotic water permeability for PAPs is 1.0(±0.3) × 10−14 cm3/s or 3.5(±1.0) × 108 water molecules per s, which is in the range of AQPs (3.4∼40.3 × 108 water molecules per s) and their current synthetic analogs, carbon nanotubes (CNTs, 9.0 × 108 water molecules per s). This permeability is an order of magnitude higher than first-generation artificial water channels (20 to ∼107 water molecules per s). Furthermore, within lipid bilayers, PAP channels can self-assemble into 2D arrays. Relevant to permeable membrane design, the pore density of PAP channel arrays (∼2.6 × 105 pores per μm2) is two orders of magnitude higher than that of CNT membranes (0.1∼2.5 × 103 pores per μm2). PAP channels thus combine the advantages of biological channels and CNTs and improve upon them through their relatively simple synthesis, chemical stability, and propensity to form arrays. PMID:26216964

  5. [Study of high temperature water vapor concentration measurement method based on absorption spectroscopy].

    PubMed

    Chen, Jiu-ying; Liu, Jian-guo; He, Jun-feng; He, Ya-bai; Zhang, Guang-le; Xu, Zhen-yu; Gang, Qiang; Wang, Liao; Yao, Lu; Yuan, Song; Ruan, Jun; Dai, Yun-hai; Kan, Rui-feng

    2014-12-01

    Tunable diode laser absorption spectroscopy (TDLAS) has been developed to realize the real-time and dynamic measurement of the combustion temperature, gas component concentration, velocity and other flow parameters, owing to its high sensitivity, fast time response, non-invasive character and robust nature. In order to obtain accurate water vapor concentration at high temperature, several absorption spectra of water vapor near 1.39 μm from 773 to 1273 K under ordinary pressure were recorded in a high temperature experiment setup using a narrow band diode laser. The absorbance of high temperature absorption spectra was calculated by combined multi-line nonlinear least squares fitting method. Two water vapor absorption lines near 7154.35 and 7157.73 cm(-1) were selected for measurement of water vapor at high temperature. A model method for high temperature water vapor concentration was first proposed. Water vapor concentration from the model method at high temperature is in accordance with theoretical reasoning, concentration measurement standard error is less than 0.2%, and the relative error is less than 6%. The feasibility of this measuring method is verified by experiment.

  6. Terahertz sensing of highly absorptive water-methanol mixtures with multiple resonances in metamaterials.

    PubMed

    Chen, Min; Singh, Leena; Xu, Ningning; Singh, Ranjan; Zhang, Weili; Xie, Lijuan

    2017-06-26

    Terahertz sensing of highly absorptive aqueous solutions remains challenging due to strong absorption of water in the terahertz regime. Here, we experimentally demonstrate a cost-effective metamaterial-based sensor integrated with terahertz time-domain spectroscopy for highly absorptive water-methanol mixture sensing. This metamaterial has simple asymmetric wire structures that support multiple resonances including a fundamental Fano resonance and higher order dipolar resonance in the terahertz regime. Both the resonance modes have strong intensity in the transmission spectra which we exploit for detection of the highly absorptive water-methanol mixtures. The experimentally characterized sensitivities of the Fano and dipole resonances for the water-methanol mixtures are found to be 160 and 305 GHz/RIU, respectively. This method provides a robust route for metamaterial-assisted terahertz sensing of highly absorptive chemical and biochemical materials with multiple resonances and high accuracy.

  7. Effect of lyophilized water extracts of Melissa officinalis on the stability of algae and linseed oil-in-water emulsion to be used as a functional ingredient in meat products.

    PubMed

    de Ciriano, Mikel García-Iñiguez; Rehecho, Sheyla; Calvo, Maria Isabel; Cavero, Rita Yolanda; Navarro, Iñigo; Astiasarán, Iciar; Ansorena, Diana

    2010-06-01

    Previous work pointed out the possibility to enhance the nutritional value of meat products using long chain omega-3 PUFA enriched emulsions. Oil-in-water emulsions elaborated with a mixture of algae and linseed oils (15:10) in order to be used as functional ingredient were stabilized with BHA (butylhydroxyanisol) or with a lyophilized water extract of Melissa officinalis L. (Lemon balm). The lipid profile of the oil mixture showed a high amount of DHA (31.7%), oleic (25.4%) and alpha-linolenic acid (12.7%) resulting in a very low omega-6/omega-3 ratio (0.12). The lyophilized extract of M. officinalis showed a high antioxidant activity (being 62ppm of the lyophilized water extract of Melissa equivalent to 200ppm of BHA, using the DPPH assay as reference), and high total phenolic content. Studying the oxidation process in the emulsions during 15days at room temperature, it could be concluded that this extract was as efficient as BHA in order to control the thiobarbituric acid reactive substances (TBARS) formation. Copyright 2010 Elsevier Ltd. All rights reserved.

  8. Boron exposure assessment using drinking water and urine in the North of Chile.

    PubMed

    Cortes, S; Reynaga-Delgado, E; Sancha, A M; Ferreccio, C

    2011-12-01

    Boron is an essential trace element for plants and humans however it is still an open question what levels of boron are actually safe for humans. This study, conducted between 2006 and 2010, measured exposure levels of boron in drinking water and urine of volunteers in Arica, an area in the North of Chile with high levels of naturally occurring boron. Samples were taken of tap and bottled water (173 and 22, respectively), as well as urine from 22 volunteers, and subsequently analyzed by inductively coupled plasma spectroscopy (ICP-OES). Boron varied in public tap water from 0.22 to 11.3mgL(-1), with a median value of 2.9mgL(-1), while concentrations of boron in bottled water varied from 0.01 to 12.2mgL(-1). Neither tap nor bottled water samples had concentrations of boron within WHO recommended limits. The concentration of boron in urine varied between 0.45 and 17.4mgL(-1), with a median of 4.28mgL(-1) and was found to be correlated with tap water sampled from the homes of the volunteers (r=0.64). Authors highly recommend that in northern Chile - where levels of boron are naturally high - that the tap and bottled water supplies be monitored in order to protect public health and that regulatory standards also be established for boron in drinking water in order to limit exposure. Copyright © 2011 Elsevier B.V. All rights reserved.

  9. Metagenomic Analysis of Water Distribution System Bacterial Communities

    EPA Science Inventory

    The microbial quality of drinking water is assessed using culture-based methods that are highly selective and that tend to underestimate the densities and diversity of microbial populations inhabiting distribution systems. In order to better understand the effect of different dis...

  10. MOLECULAR DIVERSITY OF DRINKING WATER MICROBIAL COMMUNITIES: A PHYLOGENETIC APPROACH

    EPA Science Inventory

    Culture-based methods are traditionally used to determine microbiological quality of drinking water even though these methods are highly selective and tend to underestimate the densities and diversity bacterial populations inhabiting distribution systems. In order to better under...

  11. Beyond the classical kinetic model for chronic graphite oxidation by moisture in high temperature gas-cooled reactors

    DOE PAGES

    Contescu, Cristian I.; Mee, Robert W.; Lee, Yoonjo; ...

    2017-11-03

    Four grades of nuclear graphite with various microstructures were subjected to accelerated oxidation tests in helium with traces of moisture and hydrogen in order to evaluate the effects of chronic oxidation on graphite components in high temperature gas cooled reactors. Kinetic analysis showed that the Langmuir-Hinshelwood (LH) model cannot consistently reproduce all results. In particular, at high temperatures and water partial pressures oxidation was always faster than the LH model predicts, with stronger deviations for superfine grain graphite than for medium grain grades. It was also found empirically that the apparent reaction order for water has a sigmoid-type variation withmore » temperature which follows the integral Boltzmann distribution function. This suggests that the apparent activation with temperature of graphite reactive sites that causes deviations from the LH model is rooted in specific structural and electronic properties of surface sites on graphite. A semi-global kinetic model was proposed, whereby the classical LH model was modified with a temperature-dependent reaction order for water. The new Boltzmann-enhanced model (BLH) was shown to consistently predict experimental oxidation rates over large ranges of temperature (800-1100 oC) and partial pressures of water (3-1200 Pa) and hydrogen (0-300 Pa), not only for the four grades of graphite but also for the historic grade H-451. The BLH model offers as more reliable input for modeling the chemical environment effects during the life-time operation of new grades of graphite in advanced nuclear reactors operating at high and very high temperatures.« less

  12. Beyond the classical kinetic model for chronic graphite oxidation by moisture in high temperature gas-cooled reactors

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

    Contescu, Cristian I.; Mee, Robert W.; Lee, Yoonjo

    Four grades of nuclear graphite with various microstructures were subjected to accelerated oxidation tests in helium with traces of moisture and hydrogen in order to evaluate the effects of chronic oxidation on graphite components in high temperature gas cooled reactors. Kinetic analysis showed that the Langmuir-Hinshelwood (LH) model cannot consistently reproduce all results. In particular, at high temperatures and water partial pressures oxidation was always faster than the LH model predicts, with stronger deviations for superfine grain graphite than for medium grain grades. It was also found empirically that the apparent reaction order for water has a sigmoid-type variation withmore » temperature which follows the integral Boltzmann distribution function. This suggests that the apparent activation with temperature of graphite reactive sites that causes deviations from the LH model is rooted in specific structural and electronic properties of surface sites on graphite. A semi-global kinetic model was proposed, whereby the classical LH model was modified with a temperature-dependent reaction order for water. The new Boltzmann-enhanced model (BLH) was shown to consistently predict experimental oxidation rates over large ranges of temperature (800-1100 oC) and partial pressures of water (3-1200 Pa) and hydrogen (0-300 Pa), not only for the four grades of graphite but also for the historic grade H-451. The BLH model offers as more reliable input for modeling the chemical environment effects during the life-time operation of new grades of graphite in advanced nuclear reactors operating at high and very high temperatures.« less

  13. Effects of water flow regulation on ecosystem functioning in a Mediterranean river network assessed by wood decomposition.

    PubMed

    Abril, Meritxell; Muñoz, Isabel; Casas-Ruiz, Joan P; Gómez-Gener, Lluís; Barceló, Milagros; Oliva, Francesc; Menéndez, Margarita

    2015-06-01

    Mediterranean rivers are extensively modified by flow regulation practises along their courses. An important part of the river impoundment in this area is related to the presence of small dams constructed mainly for water abstraction purposes. These projects drastically modified the ecosystem morphology, transforming lotic into lentic reaches and increasing their alternation along the river. Hydro-morphologial differences between these reaches indicate that flow regulation can trigger important changes in the ecosystem functioning. Decomposition of organic matter is an integrative process and this complexity makes it a good indicator of changes in the ecosystem. The aim of this study was to assess the effect caused by flow regulation on ecosystem functioning at the river network scale, using wood decomposition as a functional indicator. We studied the mass loss from wood sticks during three months in different lotic and lentic reaches located along a Mediterranean river basin, in both winter and summer. Additionally, we identified the environmental factors affecting decomposition rates along the river orders. The results revealed differences in decomposition rates between sites in both seasons that were principally related to the differences between stream orders. The rates were mainly related to temperature, nutrient concentrations (NO2(-), NO3(2-)) and water residence time. High-order streams with higher temperature and nutrient concentrations exhibited higher decomposition rates compared with low-order streams. The effect of the flow regulation on the decomposition rates only appeared to be significant in high orders, especially in winter, when the hydrological characteristics of lotic and lentic habitats widely varied. Lotic reaches with lower water residence time exhibited greater decomposition rates compared with lentic reaches probably due to more physical abrasion and differences in the microbial assemblages. Overall, our study revealed that in high orders the reduction of flow caused by flow regulation affects the wood decomposition indicating changes in ecosystem functioning. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. MOLECULAR DIVERSITY OF DRINKING WATER MICROBIAL COMMUNITIES: A PHYLOGENETIC APPROACH

    EPA Science Inventory

    The microbiological quality of drinking water is assessed using culture-based methods that are highly selective and that tend to underestimate the densities and diversity of microbial populations inhabiting distribution systems. In order to better understand the effect of differe...

  15. Influence of fine water droplets to temperature and humidity

    NASA Astrophysics Data System (ADS)

    Hafidzal, M. H. M.; Hamzah, A.; Manaf, M. Z. A.; Saadun, M. N. A.; Zakaria, M. S.; Roslizar, A.; Jumaidin, R.

    2015-05-01

    Excessively dry air can cause dry skin, dry eyes and exacerbation of medical conditions. Therefore, many researches have been done in order to increase humidity in our environment. One of the ways is by using water droplets. Nowadays, it is well known in market stand fan equipped with water mister in order to increase the humidity of certain area. In this study, the same concept is applied to the ceiling fan. This study uses a model that combines a humidifier which functions as cooler, ceiling fan and scaled down model of house. The objective of this study is to analyze the influence of ceiling fan humidifier to the temperature and humidity in a house. The mechanism of this small model uses batteries as the power source, connected to the fan and the humidifier. The small water tank's function is to store and supply water to the humidifier. The humidifier is used to cool the room by changing water phase to fine water droplets. Fine water droplets are created from mechanism of the humidifier, which is by increasing the kinetic energy of water molecule using high frequency vibration that overcome the holding force between water molecules. Thus, the molecule of water will change to state of gas or mist. The fan is used to spread out the mist of water to surrounding of the room in order to enhance the humidity. Thermocouple and humidity meter are used to measure temperature and humidity in some period of times. The result shows that humidity increases and temperature decreases with time. This application of water droplet can be applied in the vehicles and engine in order to decrease the temperature.

  16. [Investigation on the phenomena of bacteria exceeding standards in rural pit water treated by ultrafiltration membrane].

    PubMed

    Yue, Yinling; Zhang, Lan; Ling, Bo

    2011-11-01

    To investigate the phenomenon of bacteria exceeding standards in rural pit water, which was intermittently operated by water pump equipped with ultrafiltration membrane, and to explore the solutions. Polyvinyl chloride (PVC) alloy capillary membranes combined with UV, disinfectant, one-way valve, water-seal, high water level-water tank and direct outlet were tested. The operation on water treatment was intermittent, simulating the ways of treating pit water in the rural. The combination modes of ultrafiltration membrane with UV, disinfectant and high water level-water tank are valid in solving the problem of high turbidity and microorganism of pit water stored in cellars, the quality of effluents was consistent with the requirements of the national standards. While the combination modes of ultrafiltration membrane with one-way valve or water-seal were less desirable, more bacteria in treated water than raw water were observed because of bacteria breeding on the membrane component. In order to avoid excessive bacteria in filtered pit water caused by intermittent operation, it is recommended that for the pit water in high water level water tanks, the ultrafiltration membranes should be cleaned with disinfectants on a regular basis. The effluent pit water from underground cellars should be disinfected with UV after ultrafiltration.

  17. Extrusion induced low-order starch matrices: Enzymic hydrolysis and structure.

    PubMed

    Zhang, Bin; Dhital, Sushil; Flanagan, Bernadine M; Luckman, Paul; Halley, Peter J; Gidley, Michael J

    2015-12-10

    Waxy, normal and highwaymen maize starches were extruded with water as sole plasticizer to achieve low-order starch matrices. Of the three starches, we found that only high-amylose extrudate showed lower digestion rate/extent than starches cooked in excess water. The ordered structure of high-amylose starches in cooked and extruded forms was similar, as judged by NMR, XRD and DSC techniques, but enzyme resistance was much greater for extruded forms. Size exclusion chromatography suggested that longer chains were involved in enzyme resistance. We propose that the local molecular density of packing of amylose chains can control the digestion kinetics rather than just crystallinity, with the principle being that density sufficient to either prevent/limit binding and/or slow down catalysis can be achieved by dense amorphous packing. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. 77 FR 2718 - Don Grant; Notice of Petition for Declaratory Order and Soliciting Comments, Protests, and/or...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-19

    ... 158-foot-long, 8- foot-high high-rock-laid dam with a small reservoir; (2) a 11-foot wide by 12.5-foot... reservations of the United States; (3) would utilize surplus water or water power from a government dam; or (4... modified the project's pre- 1935 design or operation. l. Locations of the Application: Copies of this...

  19. High-order scheme for the source-sink term in a one-dimensional water temperature model

    PubMed Central

    Jing, Zheng; Kang, Ling

    2017-01-01

    The source-sink term in water temperature models represents the net heat absorbed or released by a water system. This term is very important because it accounts for solar radiation that can significantly affect water temperature, especially in lakes. However, existing numerical methods for discretizing the source-sink term are very simplistic, causing significant deviations between simulation results and measured data. To address this problem, we present a numerical method specific to the source-sink term. A vertical one-dimensional heat conduction equation was chosen to describe water temperature changes. A two-step operator-splitting method was adopted as the numerical solution. In the first step, using the undetermined coefficient method, a high-order scheme was adopted for discretizing the source-sink term. In the second step, the diffusion term was discretized using the Crank-Nicolson scheme. The effectiveness and capability of the numerical method was assessed by performing numerical tests. Then, the proposed numerical method was applied to a simulation of Guozheng Lake (located in central China). The modeling results were in an excellent agreement with measured data. PMID:28264005

  20. High-order scheme for the source-sink term in a one-dimensional water temperature model.

    PubMed

    Jing, Zheng; Kang, Ling

    2017-01-01

    The source-sink term in water temperature models represents the net heat absorbed or released by a water system. This term is very important because it accounts for solar radiation that can significantly affect water temperature, especially in lakes. However, existing numerical methods for discretizing the source-sink term are very simplistic, causing significant deviations between simulation results and measured data. To address this problem, we present a numerical method specific to the source-sink term. A vertical one-dimensional heat conduction equation was chosen to describe water temperature changes. A two-step operator-splitting method was adopted as the numerical solution. In the first step, using the undetermined coefficient method, a high-order scheme was adopted for discretizing the source-sink term. In the second step, the diffusion term was discretized using the Crank-Nicolson scheme. The effectiveness and capability of the numerical method was assessed by performing numerical tests. Then, the proposed numerical method was applied to a simulation of Guozheng Lake (located in central China). The modeling results were in an excellent agreement with measured data.

  1. The behaviour of water and sodium chloride solution confined into asbestos nanotube

    NASA Astrophysics Data System (ADS)

    Fomin, Yu. D.; Ryzhov, V. N.; Tsiok, E. N.

    2016-08-01

    We present the molecular simulation study of the behaviour of water and sodium chloride solution confined in lizardite asbestos nanotube which is a typical example of hydrophilic confinement. The local structure and orientational and dynamic properties are studied. It is shown that at low enough temperatures there is a well-defined orientational ordering of the water molecules. At high local densities corresponding to the maxima of the density distribution function, the water molecules are oriented parallel to the axis of the tube. It is also shown that the diffusion coefficient drops about two orders of magnitude comparing to the bulk case. The behaviour of sodium chloride solutions is also considered and the formation of double layer is observed.

  2. [Spatial Variability Characteristics of Water Quality and Its Driving Forces in Honghu Lake During High Water-level Period].

    PubMed

    Li, Kun; Wang, Ling; Li, Zhao-hua; Wang, Xiang-rong; Chen, Hong-bing; Wu, Zhong; Zhu, Peng

    2015-04-01

    Based on the high-density analysis of 139 monitoring points and samples in water of honghu lake with different degrees of eutrophication during the high water-level period, we could get the figures of spatial variability characteristics of pollution factors, the biomass of aquatic plants and water quality in Honghu Lake using the GIS interpolation methods. The result showed that the concentrations of TN, TP, NH4(+) -N, permanganate index gradually increased from south to north during this period, the trend of water pollution degree in Honghu Lake was the region of inflowing rivers > enclosure culture area > open water area > the lake protection area > region of the Yangtze river into the lake; and the contribution rate of water quality parameters was in the order of TN > TP > permanganate index > NH4(+), -N > DO; under the influence of industrial sewage, agricultural sewage, domestic sewage, bait, aquatic plants and water exchange, 59% of TN, 35.2% of TP, 13.7% of permanganate index, 4.3% of NH4(+)-N exceeded the water quality targets, respectively, accordingly, 66.2% of the water quality also exceeded the water quality target. Nonetheless, DO reached the water quality target due to the influences of monsoon climate and other environment factors. The spatial variation analysis could directly reflect the mutual interaction among human activity, land-use types and environment factors which had an enormous impact on Honghu Lake water environment. In order to ensure that the lake water environment is beneficial for human productions and livings, it is necessary for us to control the discharge of industrial sewage, agricultural sewage and domestic sewage, as well as the expanding area of aquaculture, all the above measures would be significant for gradually resuming the self-purification capacity of water body and finally achieving the ecological sustainable development of Honghu Lake water environment.

  3. Water Mass Classification on a Highly Variable Arctic Shelf Region: Origin of Laptev Sea Water Masses and Implications for the Nutrient Budget

    NASA Astrophysics Data System (ADS)

    Bauch, D.; Cherniavskaia, E.

    2018-03-01

    Large gradients and inter annual variations on the Laptev Sea shelf prevent the use of uniform property ranges for a classification of major water masses. The central Laptev Sea is dominated by predominantly marine waters, locally formed polynya waters and riverine summer surface waters. Marine waters enter the central Laptev Sea from the northwestern Laptev Sea shelf and originate from the Kara Sea or the Arctic Ocean halocline. Local polynya waters are formed in the Laptev Sea coastal polynyas. Riverine summer surface waters are formed from Lena river discharge and local melt. We use a principal component analysis (PCA) in order to assess the distribution and importance of water masses within the Laptev Sea. This mathematical method is applied to hydro-chemical summer data sets from the Laptev Sea from five years and allows to define water types based on objective and statistically significant criteria. We argue that the PCA-derived water types are consistent with the Laptev Sea hydrography and indeed represent the major water masses on the central Laptev Sea shelf. Budgets estimated for the thus defined major Laptev Sea water masses indicate that freshwater inflow from the western Laptev Sea is about half or in the same order of magnitude as freshwater stored in locally formed polynya waters. Imported water dominates the nutrient budget in the central Laptev Sea; and only in years with enhanced local polynya activity is the nutrient budget of the locally formed water in the same order as imported nutrients.

  4. Anomalous Debye-like dielectric relaxation of water in micro-sized confined polymeric systems.

    PubMed

    Colosi, C; Costantini, M; Barbetta, A; Cametti, C; Dentini, M

    2013-12-14

    While it is well known that spatial confinement on a nm scale affects the molecular dynamics of water resulting in a hindered dipolar reorientation, question of whether these effects could result at length scales larger than these, i.e., in confined regions of the order of μm or more, is still under debate. Here we use dielectric relaxation spectroscopy techniques to study the relaxation orientation dynamics of water entrapped in different polymeric matrices with pore sizes of the order of 100 μm, analyzing the frequency relaxation behaviour of the dielectric response. Our results show that, contrary to what has been generally thought, even in confinements which are not particularly high such as those realized here, regions typically hundred micrometers in size can affect the water structure, inducing a water phase with properties different from those of bulk water. In particular, we observe a dielectric dispersion centered in the range 10(5)-10(7) Hz, in between the one characteristic of ice (8.3 kHz at T = 0 °C) and the one of bulk water (19.2 GHz at T = 25 °C). The analysis of the dependence on temperature of the relaxation time of this unexpected contribution rules out the possibility that it can be attributed to an interfacial polarization (Maxwell-Wagner effect) and suggests a dipolar Debye-like origin due to a slow-down of the hydrogen-bonded network orientational polarization. Also at these scales, the confinement alters the structure of water, leading to a hindered reorientation. These properties imply that water confined within these polymeric porous matrices is more ordered than bulk water. These findings may be important in order to understand biological processes in cells and in different biological compartments, where water is physiologically confined.

  5. A new submarine oil-water separation system

    NASA Astrophysics Data System (ADS)

    Cai, Wen-Bin; Liu, Bo-Hong

    2017-12-01

    In order to solve the oil field losses of environmental problems and economic benefit caused by the separation of lifting production liquid to offshore platforms in the current offshore oil production, from the most basic separation principle, a new oil-water separation system has been processed of adsorption and desorption on related materials, achieving high efficiency and separation of oil and water phases. And the submarine oil-water separation device has been designed. The main structure of the device consists of gas-solid phase separation device, period separating device and adsorption device that completed high efficiency separation of oil, gas and water under the adsorption and desorption principle, and the processing capacity of the device is calculated.

  6. Polymer Surface Textured with Nanowire Bundles to Repel High-Speed Water Drops.

    PubMed

    Li, Y P; Li, X Y; Zhu, X P; Lei, M K; Lakhtakia, A

    2018-05-22

    Water drops impacting windshields of high-speed trains and aircraft as well as blades in steam turbine power generators obliquely and at high speeds are difficult to repel. Impacting drops penetrate the void regions of nanotextured and microtextured superhydrophobic coatings, with this pinning resulting in the loss of drop mobility. In order to repel high-speed water drops, we nanotextured polymer surfaces with nanowire bundles separated from their neighbors by microscale void regions, with the nanowires in a bundle separated from their neighbors by nanoscale void regions. Water drops with speeds below a critical speed rebound completely. Water drops with speeds exceeding a critical speed rebound partially, but residual droplets that begin to be pinned undergo a spontaneous dewetting process and slide off. The natural oscillations of residual droplets drive this dewetting process in the interbundle void regions, resulting in a transition from the sticky Wenzel state to the slippery Cassie state without external stimuli.

  7. Release mechanism of insulin encapsulated in trehalose ester derivative microparticles delivered via inhalation.

    PubMed

    Davidson, Iain G; Langner, Eric J; Plowman, Steven V; Blair, Julian A

    2003-03-26

    The aim of this study was to evaluate properties of amorphous oligosaccharide ester derivative (OED) microparticles in order to determine drug release mechanisms in the lung. Trehalose OEDs with a wide range of properties were synthesised using conventional methods. The interaction of spray dried amorphous microparticles (2-3 microm) with water was investigated using attenuated total reflectance Fourier transform infra-red spectroscopy (ATR-FTIR) and dynamic vapour sorption (DVS). The in vivo performance of insulin/OED microparticles was assessed using a modified Higuchi kinetic model. A modified Hansen solvent parameter approach was used to analyse the interactions with water and in vivo trends. In water or high humidity, OED powders absorb water, lose relaxation energy and crystallise. The delay of the onset of crystallisation depends on the OED and the amount of water present. Crystallisation follows first order Arrhenius kinetics and release of insulin from OED microparticles closely matches the degree of crystallisation. The induction period depends on dispersive interactions between the OED and water while crystallisation is governed by polarity and hydrogen bonding. Drug release from OED microparticles is, therefore, controlled by crystallisation of the matrix on contact with water. The pulmonary environment was found to resemble one of high humidity rather than a liquid medium. Copyright 2003 Elsevier Science B.V.

  8. Potential energy landscape of the apparent first-order phase transition between low-density and high-density amorphous ice.

    PubMed

    Giovambattista, Nicolas; Sciortino, Francesco; Starr, Francis W; Poole, Peter H

    2016-12-14

    The potential energy landscape (PEL) formalism is a valuable approach within statistical mechanics to describe supercooled liquids and glasses. Here we use the PEL formalism and computer simulations to study the pressure-induced transformations between low-density amorphous ice (LDA) and high-density amorphous ice (HDA) at different temperatures. We employ the ST2 water model for which the LDA-HDA transformations are remarkably sharp, similar to what is observed in experiments, and reminiscent of a first-order phase transition. Our results are consistent with the view that LDA and HDA configurations are associated with two distinct regions (megabasins) of the PEL that are separated by a potential energy barrier. At higher temperature, we find that low-density liquid (LDL) configurations are located in the same megabasin as LDA, and that high-density liquid (HDL) configurations are located in the same megabasin as HDA. We show that the pressure-induced LDL-HDL and LDA-HDA transformations occur along paths that interconnect these two megabasins, but that the path followed by the liquid is different from the path followed by the amorphous solid. At higher pressure, we also study the liquid-to-ice-VII first-order phase transition, and find that the behavior of the PEL properties across this transition is qualitatively similar to the changes found during the LDA-HDA transformation. This similarity supports the interpretation that the LDA-HDA transformation is a first-order phase transition between out-of-equilibrium states. Finally, we compare the PEL properties explored during the LDA-HDA transformations in ST2 water with those reported previously for SPC/E water, for which the LDA-HDA transformations are rather smooth. This comparison illuminates the previous work showing that, at accessible computer times scales, a liquid-liquid phase transition occurs in the case of ST2 water, but not for SPC/E water.

  9. Potential energy landscape of the apparent first-order phase transition between low-density and high-density amorphous ice

    NASA Astrophysics Data System (ADS)

    Giovambattista, Nicolas; Sciortino, Francesco; Starr, Francis W.; Poole, Peter H.

    2016-12-01

    The potential energy landscape (PEL) formalism is a valuable approach within statistical mechanics to describe supercooled liquids and glasses. Here we use the PEL formalism and computer simulations to study the pressure-induced transformations between low-density amorphous ice (LDA) and high-density amorphous ice (HDA) at different temperatures. We employ the ST2 water model for which the LDA-HDA transformations are remarkably sharp, similar to what is observed in experiments, and reminiscent of a first-order phase transition. Our results are consistent with the view that LDA and HDA configurations are associated with two distinct regions (megabasins) of the PEL that are separated by a potential energy barrier. At higher temperature, we find that low-density liquid (LDL) configurations are located in the same megabasin as LDA, and that high-density liquid (HDL) configurations are located in the same megabasin as HDA. We show that the pressure-induced LDL-HDL and LDA-HDA transformations occur along paths that interconnect these two megabasins, but that the path followed by the liquid is different from the path followed by the amorphous solid. At higher pressure, we also study the liquid-to-ice-VII first-order phase transition, and find that the behavior of the PEL properties across this transition is qualitatively similar to the changes found during the LDA-HDA transformation. This similarity supports the interpretation that the LDA-HDA transformation is a first-order phase transition between out-of-equilibrium states. Finally, we compare the PEL properties explored during the LDA-HDA transformations in ST2 water with those reported previously for SPC/E water, for which the LDA-HDA transformations are rather smooth. This comparison illuminates the previous work showing that, at accessible computer times scales, a liquid-liquid phase transition occurs in the case of ST2 water, but not for SPC/E water.

  10. Out-of-water constitutional self-organization of chitosan-cinnamaldehyde dynagels.

    PubMed

    Marin, Luminita; Moraru, Simona; Popescu, Maria-Cristina; Nicolescu, Alina; Zgardan, Cristina; Simionescu, Bogdan C; Barboiu, Mihail

    2014-04-14

    An investigation of the constitutional adaptive gelation process of chitosan/cinnamaldehyde (C/Cy) dynagels is reported. These gels generate timely variant macroscopic organization across extended scales. In the first stage, imine-bond formation takes place "in-water" and generates low-ordered hydrogels. The progressive formation of imine bonds further induces "out-of-water" increased reactivity within interdigitated hydrophobic self-assembled layers of Cy, with a protecting environmental effect against hydrolysis and that leads to the stabilization of the imine bonds. The hydrophobic swelling due to Cy layers at the interfaces reaches a critical step when lamellar self-organized hybrids are generated (24 hours). This induces an important restructuration of the hydrogels on the micrometric scale, thus resulting in the formation of highly ordered microporous xerogel morphologies of high potential interest for chemical separations, drug delivery, and sensors. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Magnetic porous carbon as an adsorbent for the enrichment of chlorophenols from water and peach juice samples.

    PubMed

    Wang, Chun; Ma, Ruiyang; Wu, Qiuhua; Sun, Meng; Wang, Zhi

    2014-09-26

    In this paper, porous carbon with a highly ordered structure was synthesized using zeolite ZSM-5 as a template and sucrose as a carbon source. Through the in situ reduction of Fe(3+), magnetic property was successfully introduced into the ordered porous carbon, resulting in a magnetic porous carbon (MPC). MPC was used as an adsorbent for the extraction of some chlorophenols (2-chlorophenol, 3-chlorophenol, 2,3-dichlorophenol and 3,4-dichlorophenol) from water and peach juice samples followed by high performance liquid chromatography-ultraviolet detection. Good linearity was observed in the range 1.0-100.0 ng mL(-1) and 2.0-100.0 ng mL(-1) for water and peach juice sample, respectively. The limits of detection (S/N=3) were between 0.10 and 0.30 ng mL(-1). The relative standard deviations were less than 5.3% and the recoveries of the method for the compounds were in the range from 87.8% to 102.3%. The results demonstrated that the MPC had a high adsorptive capability toward the four chlorophenols from water and peach juice samples. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. High adherence is necessary to realize health gains from water quality interventions.

    PubMed

    Brown, Joe; Clasen, Thomas

    2012-01-01

    Safe drinking water is critical for health. Household water treatment (HWT) has been recommended for improving access to potable water where existing sources are unsafe. Reports of low adherence to HWT may limit the usefulness of this approach, however. We constructed a quantitative microbial risk model to predict gains in health attributable to water quality interventions based on a range of assumptions about pre-treatment water quality; treatment effectiveness in reducing bacteria, viruses, and protozoan parasites; adherence to treatment interventions; volume of water consumed per person per day; and other variables. According to mean estimates, greater than 500 DALYs may be averted per 100,000 person-years with increased access to safe water, assuming moderately poor pre-treatment water quality that is a source of risk and high treatment adherence (>90% of water consumed is treated). A decline in adherence from 100% to 90% reduces predicted health gains by up to 96%, with sharpest declines when pre-treatment water quality is of higher risk. Results suggest that high adherence is essential in order to realize potential health gains from HWT.

  13. Correlation Between Chain Architecture and Hydration Water Structure in Polysaccharides.

    PubMed

    Grossutti, Michael; Dutcher, John R

    2016-03-14

    The physical properties of confined water can differ dramatically from those of bulk water. Hydration water associated with polysaccharides provides a particularly interesting example of confined water, because differences in polysaccharide structure provide different spatially confined environments for water sorption. We have used attenuated total reflection infrared (ATR-IR) spectroscopy to investigate the structure of hydration water in films of three different polysaccharides under controlled relative humidity (RH) conditions. We compare the results obtained for films of highly branched, dendrimer-like phytoglycogen nanoparticles to those obtained for two unbranched polysaccharides, hyaluronic acid (HA), and chitosan. We find similarities between the water structuring in the two linear polysaccharides and significant differences for phytoglycogen. In particular, the results suggest that the high degree of branching in phytoglycogen leads to a much more well-ordered water structure (low density, high connectivity network water), indicating the strong influence of chain architecture on the structuring of water. These measurements provide unique insight into the relationship between the structure and hydration of polysaccharides, which is important for understanding and exploiting these sustainable nanomaterials in a wide range of applications.

  14. High Adherence Is Necessary to Realize Health Gains from Water Quality Interventions

    PubMed Central

    Brown, Joe; Clasen, Thomas

    2012-01-01

    Background Safe drinking water is critical for health. Household water treatment (HWT) has been recommended for improving access to potable water where existing sources are unsafe. Reports of low adherence to HWT may limit the usefulness of this approach, however. Methods and Findings We constructed a quantitative microbial risk model to predict gains in health attributable to water quality interventions based on a range of assumptions about pre-treatment water quality; treatment effectiveness in reducing bacteria, viruses, and protozoan parasites; adherence to treatment interventions; volume of water consumed per person per day; and other variables. According to mean estimates, greater than 500 DALYs may be averted per 100,000 person-years with increased access to safe water, assuming moderately poor pre-treatment water quality that is a source of risk and high treatment adherence (>90% of water consumed is treated). A decline in adherence from 100% to 90% reduces predicted health gains by up to 96%, with sharpest declines when pre-treatment water quality is of higher risk. Conclusions Results suggest that high adherence is essential in order to realize potential health gains from HWT. PMID:22586491

  15. Characterization of turbulent processes by the Raman lidar system BASIL during the HD(CP)2 observational prototype experiment - HOPE

    NASA Astrophysics Data System (ADS)

    Di Girolamo, Paolo; Summa, Donato; Stelitano, Dario; Cacciani, Marco; Scoccione, Andrea; Behrendt, Andreas; Wulfmeyer, Volker

    2017-02-01

    Measurements carried out by the Raman lidar system BASIL are reported to demonstrate the capability of this instrument to characterize turbulent processes within the Convective Boundary Layer (CBL). In order to resolve the vertical profiles of turbulent variables, high resolution water vapour and temperature measurements, with a temporal resolution of 10 sec and a vertical resolution of 90 and 30 m, respectively, are considered. Measurements of higher-order moments of the turbulent fluctuations of water vapour mixing ratio and temperature are obtained based on the application of spectral and auto-covariance analyses to the water vapour mixing ratio and temperature time series. The algorithms are applied to a case study (IOP 5, 20 April 2013) from the HD(CP)2 Observational Prototype Experiment (HOPE), held in Central Germany in the spring 2013. The noise errors are demonstrated to be small enough to allow the derivation of up to fourth-order moments for both water vapour mixing ratio and temperature fluctuations with sufficient accuracy.

  16. Removal of cyanobacterial toxins by sediment passage

    NASA Astrophysics Data System (ADS)

    Gruetzmacher, G.; Boettcher, G.; Chorus, I.; Bartel, H.

    2003-04-01

    Cyanbacterial toxins ("Cyanotoxins") comprise a wide range of toxic substances produced by cyanobacteria ("blue-green algae"). Cyanobacteria occur in surface water word wide and can be found in high concentrations during so-called algal blooms when conditions are favourable (e.g. high nutrient levels, high temperatures). Some cyanobacteria produce hepato- or neurotoxins, of which the hepatotoxic microcystins are the most common in Germany. The WHO guideline value for drinking water was set at 1 μg/L. However, maximum concentrations in surface water can reach 25 mg/L, so that a secure method for toxin elimination has to be found when this water is used as source water for drinking water production. In order to assess if cyanotoxins can be removed by sediment passage the German Federal Environmental Agency (UBA) conducted laboratory- and field scale experiments as well as observations on bank filtration field sites. Laboratory experiments (batch- and column experiments for adsorption and degradation parameters) were conducted in order to vary a multitude of experimental conditions. These experiments were followed by field scale experiments on the UBA's experimental field in Berlin. This plant offers the unique possibility to conduct experiments on the behaviour of various agents - such as harmful substances - during infiltration and bank filtration under well-defined conditions on a field scale, and without releasing these substances to the environment. Finally the development of microcystin concentrations was observed between infiltrating surface water and a drinking water well along a transsecte of observation wells. The results obtained show that infiltration and bank filtration normally seem to be secure treatment methods for source water contaminated by microcystins. However, elimination was shown to be difficult under the following circumstances: - dying cyanobacterial population due to insufficient light and / or nutrients, low temperatures or application of algizides (high amount of extracellular microcystins), - sandy material with low shares of clay and silt (little adsorption), - low temperatures (delayed biodegradation), - anoxic conditions (delayed biodegradation), - missing clogging layer or "schmutzdecke" (little bacteria), - no previous contact to microcystins (non adapted bacteria). It is therefore the aim of a new project financed by the KompetenzZentrum Wasser Berlin (KWB) to focus on these critical circumstances in order to find out how to optimise artificial recharge and bank filtration regarding microcystin elimination.

  17. Formation kinetics of gemfibrozil chlorination reaction products: analysis and application.

    PubMed

    Krkosek, Wendy H; Peldszus, Sigrid; Huck, Peter M; Gagnon, Graham A

    2014-07-01

    Aqueous chlorination kinetics of the lipid regulator gemfibrozil and the formation of reaction products were investigated in deionized water over the pH range 3 to 9, and in two wastewater matrices. Chlorine oxidation of gemfibrozil was found to be highly dependent on pH. No statistically significant degradation of gemfibrozil was observed at pH values greater than 7. Gemfibrozil oxidation between pH 4 and 7 was best represented by first order kinetics. At pH 3, formation of three reaction products was observed. 4'-C1Gem was the only reaction product formed from pH 4-7 and was modeled with zero order kinetics. Chlorine oxidation of gemfibrozil in two wastewater matrices followed second order kinetics. 4'-C1Gem was only formed in wastewater with pH below 7. Deionized water rate kinetic models were applied to two wastewater effluents with gemfibrozil concentrations reported in literature in order to calculate potential mass loading rates of 4'C1Gem to the receiving water.

  18. Wildfire effects on source-water quality--Lessons from Fourmile Canyon fire, Colorado, and implications for drinking-water treatment

    USGS Publications Warehouse

    Writer, Jeffrey H.; Murphy, Sheila F.

    2012-01-01

    Forested watersheds provide high-quality source water for many communities in the western United States. These watersheds are vulnerable to wildfires, and wildfire size, fire severity, and length of fire season have increased since the middle 1980s (Westerling and others, 2006). Burned watersheds are prone to increased flooding and erosion, which can impair water-supply reservoirs, water quality, and drinking-water treatment processes. Limited information exists on the degree, timing, and duration of the effects of wildfire on water quality, making it difficult for drinking-water providers to evaluate the risk and develop management options. In order to evaluate the effects of wildfire on water quality and downstream ecosystems in the Colorado Front Range, the U.S. Geological Survey initiated a study after the 2010 Fourmile Canyon fire near Boulder, Colorado. Hydrologists frequently sampled Fourmile Creek at monitoring sites upstream and downstream of the burned area to study water-quality changes during hydrologic conditions such as base flow, spring snowmelt, and summer thunderstorms. This fact sheet summarizes principal findings from the first year of research. Stream discharge and nitrate concentrations increased downstream of the burned area during snowmelt runoff, but increases were probably within the treatment capacity of most drinking-water plants, and limited changes were observed in downstream ecosystems. During and after high-intensity thunderstorms, however, turbidity, dissolved organic carbon, nitrate, and some metals increased by 1 to 4 orders of magnitude within and downstream of the burned area. Increases of such magnitude can pose problems for water-supply reservoirs, drinking-water treatment plants, and downstream aquatic ecosystems.

  19. Potassium dichromate method of coal gasification the study of the typical organic compounds in water

    NASA Astrophysics Data System (ADS)

    Quan, Jiankang; Qu, Guangfei; Dong, Zhanneng; Lu, Pei; Cai, Yingying; Wang, Shibo

    2017-05-01

    The national standard method is adopted in this paper the water - digestion spectrophotometry for determination of the chemical oxygen demand (COD), after ultrasonic processing of coal gasification water for CODCr measurement. Using the control variable method, measured in different solution pH, ultrasonic frequency, ultrasonic power, reaction conditions of different initial solution concentration, the change of coal gasification water CODCr value under the action of ultrasonic, the experimental results shows that appear when measurement is allowed to fluctuate, data, in order to explain the phenomenon we adopt the combination of the high performance liquid chromatography and mass spectrometry before and after ultrasonic coal gasification qualitative analysis on composition of organic matter in water. To raw water sample chromatography - mass spectrometry (GC/MS) analysis, combined with the spectra analysis of each peak stands for material, select coal gasification typical organic substances in water, with the method of single digestion, the equivalent CODCr values measured after digestion. Order to produce, coal gasification water contained high concentration organic wastewater, such as the national standard method is adopted to eliminate the organic material, therefore to measure the CODCr value is lower than actual CODCr value of the emergence of the phenomenon, the experiment of the effect of ultrasound [9-13] is promote the complex organic chain rupture, also explains the actual measurement data fluctuation phenomenon in the experiment.

  20. Production of cellulose II from native cellulose by near- and supercritical water solubilization.

    PubMed

    Sasaki, Mitsuru; Adschiri, Tadafumi; Arai, Kunio

    2003-08-27

    We explored conditions for dissolving microcrystalline cellulose in high-temperature and high-pressure water without catalyst and in order to produce cellulose II in a rapid and selective manner. For understanding reactions of microcrystalline cellulose in subcritical and supercritical water, its solubilization treatment was conducted using a continuous-flow-type microreactor. It was found that cellulose could dissolve in near- and supercritical water at short treatment times of 0.02-0.4 s, resulting in the formation of cellulose II in relatively high yield after the treatment. Next, characteristics of the cellulose II obtained were investigated. As a result, it was confirmed that the relative crystallinity index and the degree of polymerization of the cellulose II were high values ranging from 80 to 60% and from 50 to 30%, respectively. From these findings, it was suggested that this method had high potential as an alternative technique for the conventional cellulose II production method.

  1. Using high hydraulic conductivity nodes to simulate seepage lakes

    USGS Publications Warehouse

    Anderson, Mary P.; Hunt, Randall J.; Krohelski, James T.; Chung, Kuopo

    2002-01-01

    In a typical ground water flow model, lakes are represented by specified head nodes requiring that lake levels be known a priori. To remove this limitation, previous researchers assigned high hydraulic conductivity (K) values to nodes that represent a lake, under the assumption that the simulated head at the nodes in the high-K zone accurately reflects lake level. The solution should also produce a constant water level across the lake. We developed a model of a simple hypothetical ground water/lake system to test whether solutions using high-K lake nodes are sensitive to the value of K selected to represent the lake. Results show that the larger the contrast between the K of the aquifer and the K of the lake nodes, the smaller the error tolerance required for the solution to converge. For our test problem, a contrast of three orders of magnitude produced a head difference across the lake of 0.005 m under a regional gradient of the order of 10−3 m/m, while a contrast of four orders of magnitude produced a head difference of 0.001 m. The high-K method was then used to simulate lake levels in Pretty Lake, Wisconsin. Results for both the hypothetical system and the application to Pretty Lake compared favorably with results using a lake package developed for MODFLOW (Merritt and Konikow 2000). While our results demonstrate that the high-K method accurately simulates lake levels, this method has more cumbersome postprocessing and longer run times than the same problem simulated using the lake package.

  2. In Situ High Temperature High Pressure MAS NMR Study on the Crystallization of AlPO 4 -5

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

    Zhao, Zhenchao; Xu, Suochang; Hu, Mary Y.

    2016-01-28

    A damped oscillating crystallization process of AlPO4-5 at the presence of small amount of water is demonstrated by in situ high temperature high pressure multinuclear MAS NMR. Crystalline AlPO4-5 is formed from an intermediate semicrystalline phase via continuous rearrangement of the local structure of amorphous precursor gel. Activated water catalyzes the rearrangement via repeatedly hydrolysis and condensation reaction. Strong interactions between organic template and inorganic species facilitate the ordered rearrangement. During the crystallization process, excess water, phosphate, and aluminums are expelled from the precursor. The oscillating crystallization reflects mass transportation between the solid and liquid phase during the crystallization process.more » This crystallization process is also applicable to AlPO4-5 crystallized in the presence of a relatively large amount of water.« less

  3. Structural and mechanical properties of glassy water in nanoscale confinement.

    PubMed

    Lombardo, Thomas G; Giovambattista, Nicolás; Debenedetti, Pablo G

    2009-01-01

    We investigate the structure and mechanical properties of glassy water confined between silica-based surfaces with continuously tunable hydrophobicity and hydrophilicity by computing and analyzing minimum energy, mechanically stable configurations (inherent structures). The structured silica substrate imposes long-range order on the first layer of water molecules under hydrophobic confinement at high density (p > or = 1.0 g cm(-3)). This proximal layer is also structured in hydrophilic confinement at very low density (p approximately 0.4 g cm(-3)). The ordering of water next to the hydrophobic surface greatly enhances the mechanical strength of thin films (0.8 nm). This leads to a substantial stress anisotropy; the transverse strength of the film exceeds the normal strength by 500 MPa. The large transverse strength results in a minimum in the equation of state of the energy landscape that does not correspond to a mechanical instability, but represents disruption of the ordered layer of water next to the wall. In addition, we find that the mode of mechanical failure is dependent on the type of confinement. Under large lateral strain, water confined by hydrophilic surfaces preferentially forms voids in the middle of the film and fails cohesively. In contrast, water under hydrophobic confinement tends to form voids near the walls and fails by loss of adhesion.

  4. Rain pH estimation based on the particulate matter pollutants and wet deposition study.

    PubMed

    Singh, Shweta; Elumalai, Suresh Pandian; Pal, Asim Kumar

    2016-09-01

    In forecasting of rain pH, the changes caused by particulate matter (PM) are generally neglected. In regions of high PM concentration like Dhanbad, the role of PM in deciding the rain pH becomes important. Present work takes into account theoretical prediction of rain pH by two methods. First method considers only acid causing gases (ACG) like CO2, SO2 and NOx in pH estimation, whereas, second method additionally accounts for effect of PM (ACG-PM). In order to predict the rain pH, site specific deposited dust that represents local PM was studied experimentally for its impact on pH of neutral water. After incorporation of PM correction factor, it was found that, rain pH values estimated were more representative of the observed ones. Fractional bias (FB) for the ACG-PM method reduced to values of the order of 10(-2) from those with order of 10(-1) for the ACG method. The study confirms neutralization of rain acidity by PM. On account of this, rain pH was found in the slightly acidic to near neutral range, despite of the high sulfate flux found in rain water. Although, the safer range of rain pH blurs the severity of acid rain from the picture, yet huge flux of acidic and other ions get transferred to water bodies, soil and ultimately to the ground water system. Simple use of rain pH for rain water quality fails to address the issues of its increased ionic composition due to the interfering pollutants and thus undermines severity of pollutants transferred from air to rain water and then to water bodies and soil. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Geoenvironmental factors related to high incidence of human urinary calculi (kidney stones) in Central Highlands of Sri Lanka.

    PubMed

    Abeywickarama, Buddhika; Ralapanawa, Udaya; Chandrajith, Rohana

    2016-10-01

    An area with extremely high incidence of urinary calculi was investigated in the view of identifying the relationship between the disease prevalence and the drinking water geochemistry. The prevalence of the kidney stone disease in the selected Padiyapelella-Hanguranketa area in Central Highlands of Sri Lanka is significantly higher compared with neighboring regions. Drinking water samples were collected from water sources that used by clinically identified kidney stone patients and healthy people. A total of 83 samples were collected and analyzed for major anions and cations. The anions in the area varied in the order HCO3 (-) > Cl(-) > SO4 (2-) > NO3 (-) and cations varied in the order Ca(2+) > Mg(2+) > Na(+) > K(+) > Fe(2+). The dissolved silica that occurs as silicic acid (H4SiO4) in natural waters varied from 8.8 to 84 mg/L in prevalence samples, while it was between 9.7 and 65 mg/L for samples from non-prevalence locations. Hydrogeochemical data obtained from the two groups were compared using the Wilcoxon rank-sum test. It showed that pH, total hardness, Na(+), Ca(2+) and Fe(2+) had significant difference (p < 0.005) between water sources used by patients and non-patients. Elemental ratio plots, Gibbs' plot and factor analysis indicated that the chemical composition of water sources in this area is strongly influenced by rock-water interactions, particularly the weathering of carbonate and silicate minerals. This study reveals a kind of association between stone formation and drinking water geochemistry as evident by the high hardness/calcium contents in spring water used by patients.

  6. The Nature of Surface Oxides on Corrosion-Resistant Nickel Alloy Covered by Alkaline Water

    PubMed Central

    2010-01-01

    A nickel alloy with high chrome and molybdenum content was found to form a highly resistive and passive oxide layer. The donor density and mobility of ions in the oxide layer has been determined as a function of the electrical potential when alkaline water layers are on the alloy surface in order to account for the relative inertness of the nickel alloy in corrosive environments. PMID:20672134

  7. A second-order Budkyo-type parameterization of landsurface hydrology

    NASA Technical Reports Server (NTRS)

    Andreou, S. A.; Eagleson, P. S.

    1982-01-01

    A simple, second order parameterization of the water fluxes at a land surface for use as the appropriate boundary condition in general circulation models of the global atmosphere was developed. The derived parameterization incorporates the high nonlinearities in the relationship between the near surface soil moisture and the evaporation, runoff and percolation fluxes. Based on the one dimensional statistical dynamic derivation of the annual water balance, it makes the transition to short term prediction of the moisture fluxes, through a Taylor expansion around the average annual soil moisture. A comparison of the suggested parameterization is made with other existing techniques and available measurements. A thermodynamic coupling is applied in order to obtain estimations of the surface ground temperature.

  8. China's water sustainability in the 21st century: a climate-informed water risk assessment covering multi-sector water demands

    NASA Astrophysics Data System (ADS)

    Chen, X.; Naresh, D.; Upmanu, L.; Hao, Z.; Dong, L.; Ju, Q.; Wang, J.; Wang, S.

    2014-05-01

    China is facing a water resources crisis with growing concerns as to the reliable supply of water for agricultural, industrial and domestic needs. High inter-annual rainfall variability and increasing consumptive use across the country exacerbates the situation further and is a constraint on future development. For water sustainability, it is necessary to examine the differences in water demand and supply and their spatio-temporal distribution in order to quantify the dimensions of the water risk. Here, a detailed quantitative assessment of water risk as measured by the spatial distribution of cumulated deficits for China is presented. Considering daily precipitation and temperature variability over fifty years and the current water demands, risk measures are developed to inform county level water deficits that account for both within-year and across-year variations in climate. We choose political rather than watershed boundaries since economic activity and water use are organized by county and the political process is best informed through that unit. As expected, the risk measures highlight North China Plain counties as highly water stressed. Regions with high water stress have high inter-annual variability in rainfall and now have depleted groundwater aquifers. The stress components due to agricultural, industrial and domestic water demands are illustrated separately to assess the vulnerability of particular sectors within the country to provide a basis for targeted policy analysis for reducing water stress.

  9. Building America Case Study: Simple Retrofit High-Efficiency Natural Gas Water Heater Field Test, Minneapolis, Minnesota

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

    High performance water heaters are typically more time consuming and costly to install in retrofit applications, making high performance water heaters difficult to justify economically. However, recent advancements in high performance water heaters have targeted the retrofit market, simplifying installations and reducing costs. Four high efficiency natural gas water heaters designed specifically for retrofit applications were installed in single-family homes along with detailed monitoring systems to characterize their savings potential, their installed efficiencies, and their ability to meet household demands. The water heaters tested for this project were designed to improve the cost-effectiveness and increase market penetration of high efficiencymore » water heaters in the residential retrofit market. The retrofit high efficiency water heaters achieved their goal of reducing costs, maintaining savings potential and installed efficiency of other high efficiency water heaters, and meeting the necessary capacity in order to improve cost-effectiveness. However, the improvements were not sufficient to achieve simple paybacks of less than ten years for the incremental cost compared to a minimum efficiency heater. Significant changes would be necessary to reduce the simple payback to six years or less. Annual energy savings in the range of $200 would also reduce paybacks to less than six years. These energy savings would require either significantly higher fuel costs (greater than $1.50 per therm) or very high usage (around 120 gallons per day). For current incremental costs, the water heater efficiency would need to be similar to that of a heat pump water heater to deliver a six year payback.« less

  10. Simple Retrofit High-Efficiency Natural Gas Water Heater Field Test

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

    Schoenbauer, Ben

    High performance water heaters are typically more time consuming and costly to install in retrofit applications, making high performance water heaters difficult to justify economically. However, recent advancements in high performance water heaters have targeted the retrofit market, simplifying installations and reducing costs. Four high efficiency natural gas water heaters designed specifically for retrofit applications were installed in single-family homes along with detailed monitoring systems to characterize their savings potential, their installed efficiencies, and their ability to meet household demands. The water heaters tested for this project were designed to improve the cost-effectiveness and increase market penetration of high efficiencymore » water heaters in the residential retrofit market. The retrofit high efficiency water heaters achieved their goal of reducing costs, maintaining savings potential and installed efficiency of other high efficiency water heaters, and meeting the necessary capacity in order to improve cost-effectiveness. However, the improvements were not sufficient to achieve simple paybacks of less than ten years for the incremental cost compared to a minimum efficiency heater. Significant changes would be necessary to reduce the simple payback to six years or less. Annual energy savings in the range of $200 would also reduce paybacks to less than six years. These energy savings would require either significantly higher fuel costs (greater than $1.50 per therm) or very high usage (around 120 gallons per day). For current incremental costs, the water heater efficiency would need to be similar to that of a heat pump water heater to deliver a six year payback.« less

  11. Construction of an evaluation index system of water resources bearing capacity: An empirical study in Xi’an, China

    NASA Astrophysics Data System (ADS)

    Qu, X. E.; Zhang, L. L.

    2017-08-01

    In this paper, a comprehensive evaluation of the water resources bearing capacity of Xi’an is performed. By constructing a comprehensive evaluation index system of the water resources bearing capacity that included water resources, economy, society, and ecological environment, we empirically studied the dynamic change and regional differences of the water resources bearing capacities of Xi’an districts through the TOPSIS method (Technique for Order Preference by Similarity to an Ideal Solution). Results show that the water resources bearing capacity of Xi’an significantly increased over time, and the contributions of the subsystems from high to low are as follows: water resources subsystem, social subsystem, ecological subsystem, and economic subsystem. Furthermore, there are large differences between the water resources bearing capacities of the different districts in Xi’an. The water resources bearing capacities from high to low are urban areas, Huxian, Zhouzhi, Gaoling, and Lantian. Overall, the water resources bearing capacity of Xi’an is still at a the lower level, which is highly related to the scarcity of water resources, population pressure, insufficient water saving consciousness, irrational industrial structure, low water-use efficiency, and so on.

  12. Effects of air vessel on water hammer in high-head pumping station

    NASA Astrophysics Data System (ADS)

    Wang, L.; Wang, F. J.; Zou, Z. C.; Li, X. N.; Zhang, J. C.

    2013-12-01

    Effects of air vessel on water hammer process in a pumping station with high-head were analyzed by using the characteristics method. The results show that the air vessel volume is the key parameter that determines the protective effect on water hammer pressure. The maximum pressure in the system declines with increasing air vessel volume. For a fixed volume of air vessel, the shape of air vessel and mounting style, such as horizontal or vertical mounting, have little effect on the water hammer. In order to obtain good protection effects, the position of air vessel should be close to the outlet of the pump. Generally, once the volume of air vessel is guaranteed, the water hammer of a entire pipeline is effectively controlled.

  13. The hydration structure at yttria-stabilized cubic zirconia (110)-water interface with sub-Ångström resolution

    DOE PAGES

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

    2016-06-15

    The interfacial hydration structure of yttria-stabilized cubic zirconia (110) surface in contact with water was determined with ~0.5 Å resolution by high-resolution X-ray reflectivity measurement. The terminal layer shows a reduced electron density compared to the following substrate lattice layers, which indicates there are additional defects generated by metal depletion as well as intrinsic oxygen vacancies, both of which are apparently filled by water species. Above this top surface layer, two additional adsorbed layers are observed forming a characteristic interfacial hydration structure. The first adsorbed layer shows abnormally high density as pure water and likely includes metal species, whereas themore » second layer consists of pure water. The observed interfacial hydration structure seems responsible for local equilibration of the defective surface in water and eventually regulating the long-term degradation processes. As a result, the multitude of water interactions with the zirconia surface results in the complex but highly ordered interfacial structure constituting the reaction front.« less

  14. Rate of antioxidant degradation and color variations in dehydrated apples as related to water activity.

    PubMed

    Lavelli, Vera; Vantaggi, Claudia

    2009-06-10

    Dehydrated apples were studied to evaluate the effects of water activity on the stability of their antioxidants and color. Apples were freeze-dried, ground, then equilibrated, and stored at eight water activity levels, ranging from 0.058 to 0.747, at 40 degrees C. Their contents of hydroxycinnamic acids, dihydrochalcones, catechin, epicatechin, polymeric flavan-3-ols, and hydroxymethylfurfural, their antioxidant activity values, and their Hunter colorimetric parameters were analyzed at different storage times. Antioxidant degradation followed pseudo-first-order kinetics and was accelerated by increasing the water activity. The order of antioxidant stability in the products at water activity levels below 0.316 was catechin, epicatechin, and ascorbic acid < total procyanidins < dihydrochalcones and p-coumaric acid < chlorogenic acid; however, in the products at water activity levels above 0.316, the degradation of all antioxidants was very fast. The hydroxymethylfurfural formation rate increased exponentially during storage, especially at high water activity levels. The antioxidant activity of the dehydrated apples decreased during storage, consistent with antioxidant loss. The variations of the colorimetric parameters, namely, lightness (L*), redness (a*), and yellowness (b*), followed pseudo-zero-order kinetics and were accelerated by increasing water activity. All analytical indices indicated that the dehydrated apples were stable at water activity levels below 0.316, with the degradation rate accelerating upon exposure to higher relative humidities. Above 0.316, a small increase in water activity of the product would sharply increase the degradation rate constants for both antioxidant and color variations.

  15. IN SITU HIGH TEMPORAL RESOLUTION ANALYSIS OF ELEMENTAL MERCURY IN NATURAL WATER (R827915)

    EPA Science Inventory

    Abstract

    Volatilization of elemental Hg represents an important Hg flux for many aquatic systems. In order to model this flux accurately, it is necessary to measure elemental Hg concentrations in air and water, as well as meteorological variables. Up to now, temporal r...

  16. Fresh Waters and Fish Diversity: Distribution, Protection and Disturbance in Tropical Australia

    PubMed Central

    Januchowski-Hartley, Stephanie R.; Pearson, Richard G.; Puschendorf, Robert; Rayner, Thomas

    2011-01-01

    Background Given the globally poor protection of fresh waters for their intrinsic ecological values, assessments are needed to determine how well fresh waters and supported fish species are incidentally protected within existing terrestrial protected-area networks, and to identify their vulnerability to human-induced disturbances. To date, gaps in data have severely constrained any attempt to explore the representation of fresh waters in tropical regions. Methodology and Results We determined the distribution of fresh waters and fish diversity in the Wet Tropics of Queensland, Australia. We then used distribution data of fresh waters, fish species, human-induced disturbances, and the terrestrial protected-area network to assess the effectiveness of terrestrial protected areas for fresh waters and fish species. We also identified human-induced disturbances likely to influence the effectiveness of freshwater protection and evaluated the vulnerability of fresh waters to these disturbances within and outside protected areas. The representation of fresh waters and fish species in the protected areas of the Wet Tropics is poor: 83% of stream types defined by order, 75% of wetland types, and 89% of fish species have less than 20% of their total Wet Tropics length, area or distribution completely within IUCN category II protected areas. Numerous disturbances affect fresh waters both within and outside of protected areas despite the high level of protection afforded to terrestrial areas in the Wet Tropics (>60% of the region). High-order streams and associated wetlands are influenced by the greatest number of human-induced disturbances and are also the least protected. Thirty-two percent of stream length upstream of protected areas has at least one human-induced disturbance present. Conclusions/Significance We demonstrate the need for greater consideration of explicit protection and off-reserve management for fresh waters and supported biodiversity by showing that, even in a region where terrestrial protection is high, it does not adequately capture fresh waters. PMID:21998708

  17. Water-Stable Nanoporous Polymer Films with Excellent Proton Conductivity.

    PubMed

    Wang, Zhengbang; Liang, Cong; Tang, Haolin; Grosjean, Sylvain; Shahnas, Artak; Lahann, Joerg; Bräse, Stefan; Wöll, Christof

    2018-03-01

    Achieving high values for proton conductivity in a material critically depends on providing hopping sites arranged in a regular fashion. Record values reported for regular, molecular crystals cannot yet be reached by technologically relevant systems, and the best values measured for polymer membranes suited for integration into devices are almost two orders of magnitude lower. Here, an alternative polymer membrane synthesis strategy based on the chemical modification of surface-mounted, monolithic, crystalline metal-organic framework thin films is demonstrated. Due to chemical crosslinking and subsequent removal of metal ions, these surface-mounted gels (SURGELs) are found to exhibit high proton conductivity (0.1 S cm -1 at 30 °C and 100% RH (relative humidity). These record values are attributed to the highly ordered polymer network structure containing regularly spaced carboxylic acid side groups. These covalently bound organic frameworks outperform conventional, ion-conductive polymers with regard to ion conductivity and water stability. Pronounced water-induced swelling, which causes severe mechanical instabilities in commercial membranes, is not observed. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Effect of dewatering on seismic performance of multi-anchor wall due to high ground water level

    NASA Astrophysics Data System (ADS)

    Kobayashi, Makoto; Miura, Kinya; Konami, Takeharu; Hayashi, Taketo; Sato, Hiroki

    2017-10-01

    Previous research reported that the ground water in the backfill of reinforced soil wall made it deteriorate. According to the damage investigation of Great East Earthquake 2011, the reinforced soil structure due to high ground water level by seismic wave were deformed remarkably. Some of them classified ultimate limit state or restorability limit state. However, more than 90% of reinforced soil structure, which suffered from this earthquake, were classified into no damage condition. Therefore, it is necessary that the seismic behaviors of multi-anchor wall due to seepage flow should be clarified in order to adopt the performance-based design in such reinforced soil structure. In this study, a series of centrifugal shaking table tests were conducted to investigate the seismic behavior of multi-anchor wall due to high ground water level. The reinforced drainage pipes were installed into the backfill in order to verify the dewatering effect and additional reinforcement. Furthermore, to check only the dewatering effect, the model tests was carried out with several ground water table that was modeled the case reinforced drainage pipes installed. The test results show unique behavior of reinforced region that moved integrally. This implies that the reinforced region has been behaved as if it became one mass, and this behavior make this structure increase seismic performance. Thus, the effectiveness of dewatering was observed remarkably because of decreasing the inertial force during earthquake.

  19. Groundwater drainage from fissures as a source for lahars

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

    Johnson, P. J.; Valentine, G. A.; Stauffer, P. H.

    One mechanism for generating lahars at volcanoes experiencing unrest is the disruption of internal aquifers. These disruptions can trigger releases of large quantities of groundwater. An example of such aquifer disruption occurred at Nevado del Huila Volcano, Colombia, during February and April 2007 when large fractures formed across the summit area of the volcano and lahars were emitted from them. Previous work interpreted that lahar volumes could not be accounted for by melted glacial snow or precipitation, and by elimination suggested that the primary water source was groundwater. Conceptual models have been developed for perched, confined aquifers that have beenmore » heated and pressurized by magma intrusions, followed by sudden pressure release and water emission during fracture formation. In this paper, we consider an alternative end member wherein water release from large fissures at volcanoes is driven by simple gravity drainage. We apply numerical modeling to quantify water discharge from the porous medium surrounding a fissure with a low-elevation free exit. If a long fracture with high vertical extent (on the order of hundreds of meters) intersects a highly connected saturated porous medium, large volumes (on order 10 3 m 3/m of crack length) of water may be released within tens of minutes. The drainage rates from the model may be adequate to account for the Nevado del Huila events if the medium surrounding the crack contains a large volume of water and has high horizontal permeability. Finally, this simple but poorly understood mechanism can present a hazard on its own or compound other processes releasing water from volcanoes.« less

  20. Groundwater drainage from fissures as a source for lahars

    NASA Astrophysics Data System (ADS)

    Johnson, P. J.; Valentine, G. A.; Stauffer, P. H.; Lowry, C. S.; Sonder, I.; Pulgarín, B. A.; Santacoloma, C. C.; Agudelo, A.

    2018-04-01

    One mechanism for generating lahars at volcanoes experiencing unrest is the disruption of internal aquifers. These disruptions can trigger releases of large quantities of groundwater. An example of such aquifer disruption occurred at Nevado del Huila Volcano, Colombia, during February and April 2007 when large fractures formed across the summit area of the volcano and lahars were emitted from them. Previous work interpreted that lahar volumes could not be accounted for by melted glacial snow or precipitation, and by elimination suggested that the primary water source was groundwater. Conceptual models have been developed for perched, confined aquifers that have been heated and pressurized by magma intrusions, followed by sudden pressure release and water emission during fracture formation. We consider an alternative end member wherein water release from large fissures at volcanoes is driven by simple gravity drainage. We apply numerical modeling to quantify water discharge from the porous medium surrounding a fissure with a low-elevation free exit. If a long fracture with high vertical extent (on the order of hundreds of meters) intersects a highly connected saturated porous medium, large volumes (on order 103 m3/m of crack length) of water may be released within tens of minutes. The drainage rates from the model may be adequate to account for the Nevado del Huila events if the medium surrounding the crack contains a large volume of water and has high horizontal permeability. This simple but poorly understood mechanism can present a hazard on its own or compound other processes releasing water from volcanoes.

  1. Groundwater drainage from fissures as a source for lahars

    DOE PAGES

    Johnson, P. J.; Valentine, G. A.; Stauffer, P. H.; ...

    2018-03-22

    One mechanism for generating lahars at volcanoes experiencing unrest is the disruption of internal aquifers. These disruptions can trigger releases of large quantities of groundwater. An example of such aquifer disruption occurred at Nevado del Huila Volcano, Colombia, during February and April 2007 when large fractures formed across the summit area of the volcano and lahars were emitted from them. Previous work interpreted that lahar volumes could not be accounted for by melted glacial snow or precipitation, and by elimination suggested that the primary water source was groundwater. Conceptual models have been developed for perched, confined aquifers that have beenmore » heated and pressurized by magma intrusions, followed by sudden pressure release and water emission during fracture formation. In this paper, we consider an alternative end member wherein water release from large fissures at volcanoes is driven by simple gravity drainage. We apply numerical modeling to quantify water discharge from the porous medium surrounding a fissure with a low-elevation free exit. If a long fracture with high vertical extent (on the order of hundreds of meters) intersects a highly connected saturated porous medium, large volumes (on order 10 3 m 3/m of crack length) of water may be released within tens of minutes. The drainage rates from the model may be adequate to account for the Nevado del Huila events if the medium surrounding the crack contains a large volume of water and has high horizontal permeability. Finally, this simple but poorly understood mechanism can present a hazard on its own or compound other processes releasing water from volcanoes.« less

  2. Refined energetic ordering for sulphate-water (n = 3-6) clusters using high-level electronic structure calculations

    NASA Astrophysics Data System (ADS)

    Lambrecht, Daniel S.; McCaslin, Laura; Xantheas, Sotiris S.; Epifanovsky, Evgeny; Head-Gordon, Martin

    2012-10-01

    This work reports refinements of the energetic ordering of the known low-energy structures of sulphate-water clusters ? (n = 3-6) using high-level electronic structure methods. Coupled cluster singles and doubles with perturbative triples (CCSD(T)) is used in combination with an estimate of basis set effects up to the complete basis set limit using second-order Møller-Plesset theory. Harmonic zero-point energy (ZPE), included at the B3LYP/6-311 + + G(3df,3pd) level, was found to have a significant effect on the energetic ordering. In fact, we show that the energetic ordering is a result of a delicate balance between the electronic and vibrational energies. Limitations of the ZPE calculations, both due to electronic structure errors, and use of the harmonic approximation, probably constitute the largest remaining errors. Due to the often small energy differences between cluster isomers, and the significant role of ZPE, deuteration can alter the relative energies of low-lying structures, and, when it is applied in conjunction with calculated harmonic ZPEs, even alters the global minimum for n = 5. Experiments on deuterated clusters, as well as more sophisticated vibrational calculations, may therefore be quite interesting.

  3. A new modeling strategy for third-order fast high-performance liquid chromatographic data with fluorescence detection. Quantitation of fluoroquinolones in water samples.

    PubMed

    Alcaráz, Mirta R; Bortolato, Santiago A; Goicoechea, Héctor C; Olivieri, Alejandro C

    2015-03-01

    Matrix augmentation is regularly employed in extended multivariate curve resolution-alternating least-squares (MCR-ALS), as applied to analytical calibration based on second- and third-order data. However, this highly useful concept has almost no correspondence in parallel factor analysis (PARAFAC) of third-order data. In the present work, we propose a strategy to process third-order chromatographic data with matrix fluorescence detection, based on an Augmented PARAFAC model. The latter involves decomposition of a three-way data array augmented along the elution time mode with data for the calibration samples and for each of the test samples. A set of excitation-emission fluorescence matrices, measured at different chromatographic elution times for drinking water samples, containing three fluoroquinolones and uncalibrated interferences, were evaluated using this approach. Augmented PARAFAC exploits the second-order advantage, even in the presence of significant changes in chromatographic profiles from run to run. The obtained relative errors of prediction were ca. 10 % for ofloxacin, ciprofloxacin, and danofloxacin, with a significant enhancement in analytical figures of merit in comparison with previous reports. The results are compared with those furnished by MCR-ALS.

  4. Exploring results of the possibility on detecting cosmic ray particles by acoustic way

    NASA Technical Reports Server (NTRS)

    Jiang, Y.; Yuan, Y.; Li, Y.; Chen, D.; Zheng, R.; Song, J.

    1985-01-01

    It has been demonstrated experimentally and theoretically that high energy particles produce detectable sounds in water. However, no one has been able to detect an acoustic signal generated by a high energy cosmic ray particle in water. Results show that transient ultrasonic signals in a large lake or reservoir are fairly complex and that the transient signals under water may arise mainly from sound radiation from microbubbles. This field is not explored in detail. Perhaps, the sounds created by cosmic ray particles hide in these ultrasonic signals. In order to develop the technique of acoustic detection, it is most important to make a thorough investigation of these ultrasonic signals in water.

  5. Simple Retrofit High-Efficiency Natural Gas Water Heater Field Test

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

    Schoenbauer, Ben

    High-performance water heaters are typically more time consuming and costly to install in retrofit applications, making high performance water heaters difficult to justify economically. However, recent advancements in high performance water heaters have targeted the retrofit market, simplifying installations and reducing costs. Four high efficiency natural gas water heaters designed specifically for retrofit applications were installed in single-family homes along with detailed monitoring systems to characterize their savings potential, their installed efficiencies, and their ability to meet household demands. The water heaters tested for this project were designed to improve the cost-effectiveness and increase market penetration of high efficiency watermore » heaters in the residential retrofit market. The retrofit high efficiency water heaters achieved their goal of reducing costs, maintaining savings potential and installed efficiency of other high efficiency water heaters, and meeting the necessary capacity in order to improve cost-effectiveness. However, the improvements were not sufficient to achieve simple paybacks of less than ten years for the incremental cost compared to a minimum efficiency heater. Significant changes would be necessary to reduce the simple payback to six years or less. Annual energy savings in the range of $200 would also reduce paybacks to less than six years. These energy savings would require either significantly higher fuel costs (greater than $1.50 per therm) or very high usage (around 120 gallons per day). For current incremental costs, the water heater efficiency would need to be similar to that of a heat pump water heater to deliver a six year payback.« less

  6. The effect of water stress on super-high- density 'Koroneiki' olive oil quality.

    PubMed

    Dag, Arnon; Naor, Amos; Ben-Gal, Alon; Harlev, Guy; Zipori, Isaac; Schneider, Doron; Birger, Reuven; Peres, Moti; Gal, Yoni; Kerem, Zohar

    2015-08-15

    Over the last two decades, the area of cultivated super-high-density olive orchards has increased rapidly. Water stress is an important tool in super-high-density orchards to reduce tree growth and promote suitability for overhead mechanical harvesters. Little is known regarding the effect of water stress in super-high-density orchards on oil quality parameters. In this study the effect of irrigation rate on oil quality parameters was evaluated in a six-year-old super-high-density 'Koreneiki' olive orchard for five consecutive seasons. Five water status levels, determined by irrigating in order to maintain various midday stem water potential threshold values (-1.5, -2, -2.5, -3 and -4 MPa), were applied during the oil accumulation stage. The MUFA/PUFA ratio and free fatty acid content generally decreased as a function of increasing tree water stress. In most seasons a reduction in polyphenols was found with decreasing irrigation level. Peroxide value was not affected by the water stress level. The present study demonstrates that limiting irrigation and exposure of olive trees to water stress in a super-high-density orchard lowers free fatty acid content and therefore benefits oil quality. However, the decreased MUFA/PUFA ratio and the reduction in polyphenol content that were also found under increased water stress negatively influence oil quality. © 2014 Society of Chemical Industry.

  7. Multi-spark discharge system for preparation of nutritious water

    NASA Astrophysics Data System (ADS)

    Nakaso, Tetsushi; Harigai, Toru; Kusumawan, Sholihatta Aziz; Shimomura, Tomoya; Tanimoto, Tsuyoshi; Suda, Yoshiyuki; Takikawa, Hirofumi

    2018-01-01

    The nitrogen compound concentration in water is increased by atmospheric-pressure plasma discharge treatment. A rod-to-water electrode discharge treatment system using plasma discharge has been developed by our group to obtain water with a high concentration of nitrogen compounds, and this plasma-treated water improves the growth of chrysanthemum roots. However, it is difficult to apply the system to the agriculture because the amount of treated water obtained by using the system too small. In this study, a multi-spark discharge system (MSDS) equipped multiple spark plugs is presented to obtain a large amount of plasma-treated water. The MSDS consisted of inexpensive parts in order to reduce the system introduction cost for agriculture. To suppress the temperature increase of the spark plugs, the 9 spark plugs were divided into 3 groups, which were discharged in order. The plasma-treated water with a NO3- concentration of 50 mg/L was prepared using the MSDS for 90 min, and the treatment efficiency was about 6 times higher than that of our previous system. It was confirmed that the NO2-, O3, and H2O2 concentrations in the water were also increased by treating the water using the MSDS.

  8. Potential Energy Landscape of the Liquid-Liquid Phase Transition in Water and the transformation between Low-Density and High-Density Amorphous Ice

    NASA Astrophysics Data System (ADS)

    Giovambattista, N.; Sciortino, F.; Starr, F. W.; Poole, P. H.

    The potential energy landscape (PEL) formalism is a valuable approach within statistical mechanics for describing supercooled liquids and glasses. We use the PEL formalism and computer simulations to study the transformation between low-density (LDL) and high-density liquid (HDL) water, and between low-density (LDA) and high-density amorphous ice (HDA). We employ the ST2 water model that exhibits a LDL-HDL first-order phase transition and a sharp LDA-HDA transformation, as observed in experiments. Our results are consistent with the view that LDA and HDA configurations are associated with two distinct regions (megabasins) of the PEL that are separated by a potential energy barrier. At higher temperature, we find that LDL configurations are located in the same megabasin as LDA, and that HDL configurations are located in the same megabasin as HDA. We show that the pressure-induced LDL-HDL and LDA-HDA transformations occur along paths that interconnect these two megabasins, but that the path followed by the liquid and the amorphous ice differ. We also study the liquid-to-ice-VII first-order phase transition. The PEL properties across this transition are qualitatively similar to the changes found during the LDA-HDA transformation, supporting the interpretation that the LDA-HDA transformation is a first-order-like phase transition between out-of-equilibrium states.

  9. Coplanar surface barrier discharge ignited in water vapor—a selective source of OH radicals proved by (TA)LIF measurement

    NASA Astrophysics Data System (ADS)

    Procházka, V.; Tučeková, Z.; Dvořák, P.; Kováčik, D.; Slavíček, P.; Zahoranová, A.; Voráč, J.

    2018-01-01

    Coplanar dielectric barrier discharge (DBD) was ignited in pure water vapor at atmospheric pressure in order to generate highly oxidizing plasma with one specific type of reactive radicals. In order to prevent water condensation the used plasma reactor was heated to 120 {}\\circ C. The composition of the radical species in the discharge was studied by methods based on laser-induced fluorescence (LIF) and compared with analogous measurements realized in the same coplanar DBD ignited in air. Fast collisional processes and laser-surface interaction were taken into account during LIF data processing. It was found that coplanar DBD ignited in water vapor produces hydroxyl (OH) radicals with concentration in the order of 1020 m-3, which is 10× higher than the value measured in discharge in humid air (40% relative humidity at 21 {}\\circ C). The concentration of atomic hydrogen radicals in the DBD ignited in water vapor was below the detection limit, which proves that the generation of oxidizing plasma with dominance of one specific type of reactive radicals was achieved. The temporal evolution, spatial distribution, power dependence and rotational temperature of the OH radicals was determined in the DBD ignited in both water vapor and air.

  10. An engineered polypeptide around nano-sized manganese-calcium oxide: copying plants for water oxidation.

    PubMed

    Najafpour, Mohammad Mahdi; Ghobadi, Mohadeseh Zarei; Sarvi, Bahram; Haghighi, Behzad

    2015-09-14

    Synthesis of new efficient catalysts inspired by Nature is a key goal in the production of clean fuel. Different compounds based on manganese oxide have been investigated in order to find their water-oxidation activity. Herein, we introduce a novel engineered polypeptide containing tyrosine around nano-sized manganese-calcium oxide, which was shown to be a highly active catalyst toward water oxidation at low overpotential (240 mV), with high turnover frequency of 1.5 × 10(-2) s(-1) at pH = 6.3 in the Mn(III)/Mn(IV) oxidation range. The compound is a novel structural and efficient functional model for the water-oxidizing complex in Photosystem II. A new proposed clever strategy used by Nature in water oxidation is also discussed. The new model of the water-oxidizing complex opens a new perspective for synthesis of efficient water-oxidation catalysts.

  11. A case study of dissolved air flotation for seasonal high turbidity water in Korea.

    PubMed

    Kwon, S B; Ahn, H W; Ahn, C J; Wang, C K

    2004-01-01

    A DAF (Dissolved-Air-Flotation) process has been designed considering raw water quality characteristics in Korea. Although direct filtration is usually operated, DAF is operated when freshwater algae blooms occur or raw water turbidity becomes high. Pre-sedimentation is operated in case when the raw water turbidity is very high due to rainstorms. A main feature of this plant is that the operation mode can be changed (controlled) based on the characteristics of the raw water to optimize the effluent quality and the operation costs. Treatment capacity (surface loading rate) and efficiency of DAF was found to be better than the conventional sedimentation process. Moreover, low-density particles (algae and alum flocs) are easily separated while the removal of them by sedimentation is more difficult. One of the main concerns for DAF operation is a high raw water turbidity. DAF is not adequate for raw water, which is more turbid than 100 NTU. In order to avoid this problem, pre-sedimentation basins are installed in the DAF plant to decrease the turbidity of the DAF inflow. For simulation of the actual operation, bench and full-scale tests were performed for highly turbid water conditions. Consequently, it is suggested that pre-sedimentation with optimum coagulation prior to DAF is the appropriate treatment scheme.

  12. Improving surface-subsurface water budgeting using high resolution satellite imagery applied on a brownfield.

    PubMed

    Dujardin, J; Batelaan, O; Canters, F; Boel, S; Anibas, C; Bronders, J

    2011-01-15

    The estimation of surface-subsurface water interactions is complex and highly variable in space and time. It is even more complex when it has to be estimated in urban areas, because of the complex patterns of the land-cover in these areas. In this research a modeling approach with integrated remote sensing analysis has been developed for estimating water fluxes in urban environments. The methodology was developed with the aim to simulate fluxes of contaminants from polluted sites. Groundwater pollution in urban environments is linked to patterns of land use and hence it is essential to characterize the land cover in a detail. An object-oriented classification approach applied on high-resolution satellite data has been adopted. To assign the image objects to one of the land-cover classes a multiple layer perceptron approach was adopted (Kappa of 0.86). Groundwater recharge has been simulated using the spatially distributed WetSpass model and the subsurface water flow using MODFLOW in order to identify and budget water fluxes. The developed methodology is applied to a brownfield case site in Vilvoorde, Brussels (Belgium). The obtained land use map has a strong impact on the groundwater recharge, resulting in a high spatial variability. Simulated groundwater fluxes from brownfield to the receiving River Zenne were independently verified by measurements and simulation of groundwater-surface water interaction based on thermal gradients in the river bed. It is concluded that in order to better quantify total fluxes of contaminants from brownfields in the groundwater, remote sensing imagery can be operationally integrated in a modeling procedure. Copyright © 2010 Elsevier B.V. All rights reserved.

  13. Validation of CFD simulation of recoilless EOD water cannon by firing experiments with high speed camera

    NASA Astrophysics Data System (ADS)

    Chantrasmi, Tonkid; Hongthong, Premsiri; Kongkaniti, Manop

    2018-01-01

    Water cannon used by Explosive Ordnance Disposal (EOD) were designed to propel a burst of water jet moving at high speed to target and disrupt an improvised explosive device (IED). The cannon could be mounted on a remotely controlled robot, so it is highly desirable for the cannon to be recoilless in order not to damage the robot after firing. In the previous work, a nonconventional design of the water cannon was conceived. The recoil was greatly reduced by backward sprays of water through a ring of slotted holes around the muzzle. This minimizes the need to manufacture new parts by utilizing all off-the-shelf components except the tailor-made muzzle. The design was then investigated numerically by a series of Computational Fluid Dynamics (CFD) simulations. In this work, high speed camera was employed in firing experiments to capture the motion of the water jet and the backward sprays. It was found that the experimental data agreed well with the simulation results in term of averaged exit velocities.

  14. On the nature of a supposed water model

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

    Heckmann, Lotta, E-mail: lotta@fkp.tu-darmstadt.de; Drossel, Barbara

    2014-08-15

    A cell model that has been proposed by Stanley and Franzese in 2002 for modeling water is based on Potts variables that represent the possible orientations of bonds between water molecules. We show that in the liquid phase, where all cells are occupied by a molecule, the Hamiltonian of the cell model can be rewritten as a Hamiltonian of a conventional Potts model, albeit with two types of coupling constants. We argue that such a model, while having a first-order phase transition, cannot display the critical end point that is postulated for the phase transition between a high- and low-densitymore » liquid. A closer look at the mean-field calculations that claim to find such an end point in the cell model reveals that the mean-field theory is constructed such that the symmetry constraints on the order parameter are violated. This is equivalent to introducing an external field. The introduction of such a field can be given a physical justification due to the fact that water does not have the type of long-range order occurring in the Potts model.« less

  15. Characterization of Turbulent Processes by the Raman Lidar System Basil in the Frame of the HD(CP)2 Observational Prototype Experiment - Hope

    NASA Astrophysics Data System (ADS)

    Di Girolamo, Paolo; Summa, Donato; Stelitano, Dario; Cacciani, Marco; Scoccione, Andrea; Behrendt, Andreas; Wulfmeyer, Volker

    2016-06-01

    Measurements carried out by the Raman lidar system BASIL are reported to demonstrate the capability of this instrument to characterize turbulent processes within the Convective Boundary Layer (CBL). In order to resolve the vertical profiles of turbulent variables, high resolution water vapour and temperature measurements, with a temporal resolution of 10 sec and a vertical resolution of 90 and 210 m, respectively, are considered. Measurements of higher-order moments of the turbulent fluctuations of water vapour mixing ratio and temperature are obtained based on the application of spectral and auto-covariance analyses to the water vapour mixing ratio and temperature time series. The algorithms are applied to a case study (IOP 5, 20 April 2013) from the HD(CP)2 Observational Prototype Experiment (HOPE), held in Central Germany in the spring 2013. The noise errors are demonstrated to be small enough to allow the derivation of up to fourth-order moments for both water vapour mixing ratio and temperature fluctuations with sufficient accuracy.

  16. China's water sustainability in the 21st century: a climate informed water risk assessment covering multi-sector water demands

    NASA Astrophysics Data System (ADS)

    Chen, X.; Devineni, N.; Lall, U.; Hao, Z.; Dong, L.; Ju, Q.; Wang, J.; Wang, S.

    2013-08-01

    China is facing a water resources crisis with growing concerns as to the reliable supply of water for agricultural, industrial and domestic needs. High inter-annual rainfall variability and increasing consumptive use across the country exacerbates the situation further and is a constraint on future development. For water sustainability, it is necessary to examine the differences in water demand and supply and their spatio-temporal distribution in order to quantify the dimensions of the water risk. Here, a detailed quantitative assessment of water risk as measured by the distribution of cumulated deficits for China is presented. Considering daily precipitation and temperature variability over fifty years and the current water demands, risk measures are developed to inform county level water deficits that account for both within year and across year variations in climate. We choose political rather than watershed boundaries since economic activity and water use are organized by county and the political process is best informed through that unit. The risk measures highlight North China Plain counties as highly water stressed. Regions with high water stress are typically the regions with high inter-annual variability in rainfall and now have depleted groundwater aquifers. The stress components due to agricultural, industrial and domestic water demands are illustrated separately to assess the vulnerability of particular sectors within the country to provide a basis for targeted policy analysis for reducing water stress.

  17. Short, intermediate and long range order in amorphous ices

    NASA Astrophysics Data System (ADS)

    Martelli, Fausto; Torquato, Salvatore; Giovanbattista, Nicolas; Car, Roberto

    Water exhibits polyamorphism, i.e., it exists in more than one amorphous state. The most common forms of glassy water are the low-density amorphous (LDA) and the high-density amorphous (HDA) ices. LDA, the most abundant form of ice in the Universe, transforms into HDA upon isothermal compression. We model the transformation of LDA into HDA under isothermal compression with classical molecular dynamics simulations. We analyze the molecular structures with a recently introduced scalar order metric to measure short and intermediate range order. In addition, we rank the structures by their degree of hyperuniformity, i.e.,the extent to which long range density fluctuations are suppressed. F.M. and R.C. acknowledge support from the Department of Energy (DOE) under Grant No. DE-SC0008626.

  18. Influence of multi-industrial activities on trace metal contamination: an approach towards surface water body in the vicinity of Dhaka Export Processing Zone (DEPZ).

    PubMed

    Ahmed, Golam; Miah, M Arzu; Anawar, Hossain M; Chowdhury, Didarul A; Ahmad, Jasim U

    2012-07-01

    Industrial wastewater discharged into aquatic ecosystems either directly or because of inadequate treatment of process water can increase the concentrations of pollutants such as toxic metals and others, and subsequently deteriorate water quality, environmental ecology and human health in the Dhaka Export Processing Zone (DEPZ), the largest industrial belt of 6-EPZ in Bangladesh. Therefore, in order to monitor the contamination levels, this study collected water samples from composite effluent points inside DEPZ and the surrounding surface water body connected to effluent disposal sites and determined the environmental hazards by chemical analysis and statistical approach. The water samples were analysed by inductively coupled plasma mass spectrometry to determine 12 trace metals such as As, Ag, Cr, Co, Cu, Li, Ni, Pb, Se, Sr, V and Zn in order to assess the influence of multi-industrial activities on metal concentrations. The composite effluents and surface waters from lagoons were characterized by a strong colour and high concentrations of biochemical oxygen demand, chemical oxygen demand, electrical conductivity, pH, total alkalinity, total hardness, total organic carbon, Turb., Cl(-), total suspended solids and total dissolved solids, which were above the limit of Bangladesh industrial effluent standards, but dissolved oxygen concentration was lower than the standard value. The measurement of skewness and kurtosis values showed asymmetric and abnormal distribution of the elements in the respective phases. The mean trend of variation was found in a decreasing order: Zn > Cu > Sr > Pb > Ni > Cr > Li > Co > V > Se > As > Ag in composite industrial effluents and Zn > Cu > Sr > Pb > Ni > Cr > Li > V > As > Ag > Co > Se in surface waters near the DEPZ. The strong correlations between effluent and surface water metal contents indicate that industrial wastewaters discharged from DEPZ have a strong influence on the contamination of the surrounding water bodies by toxic metals. The average contamination factors were reported to be 0.70-96.57 and 2.85-1,462 for industrial effluents and surface waters, respectively. The results reveal that the surface water in the area is highly contaminated with very high concentrations of some heavy/toxic metals like Zn, Pb, Cu, Ni and Cr; their average contamination factors are 1,460, 860, 136, 74.71 and 4.9, respectively. The concentrations of the metals in effluent and surface water were much higher than the permissible limits for drinking water and the world average concentrations in surface water. Therefore, the discharged effluent and surface water may create health hazards especially for people working and living inside and in the surrounding area of DEPZ.

  19. Various nanoparticle morphologies and surface properties of waterborne polyurethane controlled by water

    PubMed Central

    Zhou, Xing; Fang, Changqing; Lei, Wanqing; Du, Jie; Huang, Tingyi; Li, Yan; Cheng, Youliang

    2016-01-01

    Water plays important roles in organic reactions such as polyurethane synthesis, and the aqueous solution environment affects polymer morphology and other properties. This paper focuses on the morphology and surface properties of waterborne polyurethane resulting from the organic reaction in water involving different forms (solid and liquid), temperatures and aqueous solutions. We provide evidence from TEM observations that the appearance of polyurethane nanoparticles in aqueous solutions presents diverse forms, including imperfect spheres, perfect spheres, perfect and homogenous spheres and tubes. Based on the results on FTIR, GPC, AFM and XRD experiments, we suggest that the shape of the nanoparticles may be decided by the crimp degree (i.e., the degree of polyurethane chains intertangling in the water environment) and order degree, which are determined by the molecular weight (Mn) and hydrogen bonds. Meanwhile, solid water and high-temperature water can both reduce hard segments that gather on the polyurethane film surface to reduce hydrophilic groups and produce a soft surface. Our findings show that water may play key roles in aqueous polymer formation and bring order to molecular chains. PMID:27687001

  20. Superstable Ultrathin Water Film Confined in a Hydrophilized Carbon Nanotube.

    PubMed

    Tomo, Yoko; Askounis, Alexandros; Ikuta, Tatsuya; Takata, Yasuyuki; Sefiane, Khellil; Takahashi, Koji

    2018-03-14

    Fluids confined in a nanoscale space behave differently than in the bulk due to strong interactions between fluid molecules and solid atoms. Here, we observed water confined inside "open" hydrophilized carbon nanotubes (CNT), with diameter of tens of nanometers, using transmission electron microscopy (TEM). A 1-7 nm water film adhering to most of the inner wall surface was observed and remained stable in the high vacuum (order of 10 -5 Pa) of the TEM. The superstability of this film was attributed to a combination of curvature, nanoroughness, and confinement resulting in a lower vapor pressure for water and hence inhibiting its vaporization. Occasional, suspended ultrathin water film with thickness of 3-20 nm were found and remained stable inside the CNT. This film thickness is 1 order of magnitude smaller than the critical film thickness (about 40 nm) reported by the Derjaguin-Landau-Verwey-Overbeek theory and previous experimental investigations. The stability of the suspended ultrathin water film is attributed to the additional molecular interactions due to the extended water meniscus, which balances the rest of the disjoining pressures.

  1. Patterns of nocturnal rehydration in root tissues of Vaccinium corymbosum L. under severe drought conditions

    PubMed Central

    Valenzuela-Estrada, Luis R.; Richards, James H.; Diaz, Andres; Eissensat, David M.

    2009-01-01

    Although roots in dry soil layers are commonly rehydrated by internal hydraulic redistribution during the nocturnal period, patterns of tissue rehydration are poorly understood. Rates of nocturnal rehydration were examined in roots of different orders in Vaccinium corymbosum L. ‘Bluecrop’ (Northern highbush blueberry) grown in a split-pot system with one set of roots in relatively moist soil and the other set of roots in dry soil. Vaccinium is noted for a highly branched and extremely fine root system. It is hypothesized that nocturnal root tissue rehydration would be slow, especially in the distal root orders because of their greater hydraulic constraints (smaller vessel diameters and fewer number of vessels). Vaccinium root hydraulic properties delayed internal water movement. Even when water was readily available to roots in the wet soil and transpiration was minimal, it took a whole night-time period of 12 h for the distal finest roots (1st to 4th order) under dry soil conditions to reach the same water potentials as fine roots in moist soil (1st to 4th order). Even though roots under dry soil equilibrated with roots in moist soil, the equilibrium point reached before sunrise was about –1.2 MPa, indicating that tissues were not fully rehydrated. Using a single-branch root model, it was estimated that individual roots exhibiting the lowest water potentials in dry soil were 1st order roots (distal finest roots of the root system). However, considered at the branch level, root orders with the highest hydraulic resistances corresponded to the lowest orders of the permanent root system (3rd-, 4th-, and 5th-order roots), thus indicating possible locations of hydraulic safety control in the root system of this species. PMID:19188275

  2. Patterns of nocturnal rehydration in root tissues of Vaccinium corymbosum L. under severe drought conditions.

    PubMed

    Valenzuela-Estrada, Luis R; Richards, James H; Diaz, Andres; Eissensat, David M

    2009-01-01

    Although roots in dry soil layers are commonly rehydrated by internal hydraulic redistribution during the nocturnal period, patterns of tissue rehydration are poorly understood. Rates of nocturnal rehydration were examined in roots of different orders in Vaccinium corymbosum L. 'Bluecrop' (Northern highbush blueberry) grown in a split-pot system with one set of roots in relatively moist soil and the other set of roots in dry soil. Vaccinium is noted for a highly branched and extremely fine root system. It is hypothesized that nocturnal root tissue rehydration would be slow, especially in the distal root orders because of their greater hydraulic constraints (smaller vessel diameters and fewer number of vessels). Vaccinium root hydraulic properties delayed internal water movement. Even when water was readily available to roots in the wet soil and transpiration was minimal, it took a whole night-time period of 12 h for the distal finest roots (1st to 4th order) under dry soil conditions to reach the same water potentials as fine roots in moist soil (1st to 4th order). Even though roots under dry soil equilibrated with roots in moist soil, the equilibrium point reached before sunrise was about -1.2 MPa, indicating that tissues were not fully rehydrated. Using a single-branch root model, it was estimated that individual roots exhibiting the lowest water potentials in dry soil were 1st order roots (distal finest roots of the root system). However, considered at the branch level, root orders with the highest hydraulic resistances corresponded to the lowest orders of the permanent root system (3rd-, 4th-, and 5th-order roots), thus indicating possible locations of hydraulic safety control in the root system of this species.

  3. Ultrahigh Ionic Conduction in Water-Stable Close-Packed Metal-Carbonate Frameworks.

    PubMed

    Manna, Biplab; Desai, Aamod V; Illathvalappil, Rajith; Gupta, Kriti; Sen, Arunabha; Kurungot, Sreekumar; Ghosh, Sujit K

    2017-08-21

    Utilization of the robust metal-carbonate backbone in a series of water-stable, anionic frameworks has been harnessed for the function of highly efficient solid-state ion-conduction. The compact organization of hydrophilic guest ions facilitates water-assisted ion-conduction in all the compounds. The dense packing of the compounds imparts high ion-conducting ability and minimizes the possibility of fuel crossover, making this approach promising for design and development of compounds as potential components of energy devices. This work presents the first report of evaluating ion-conduction in a purely metal-carbonate framework, which exhibits high ion-conductivity on the order of 10 -2 S cm -1 along with very low activation energy, which is comparable to highly conducting well-known crystalline coordination polymers or commercialized organic polymers like Nafion.

  4. Chemical and physical characterisation of water in an alpine permafrost area (Col d'Olen LTER site, Italian NW-Alps)

    NASA Astrophysics Data System (ADS)

    Giardino, Marco; Colombo, Nicola; Fratianni, Simona; Guenzi, Diego; Acquaotta, Fiorella; Perotti, Luigi; Freppaz, Michele; Godone, Danilo; Said Pullicino, Daniel; Martin, Maria; Viglietti, Davide; Gorra, Roberta; Mania, Ilaria; Viviano, Gaetano; Salerno, Franco; Balestrini, Raffaella

    2015-04-01

    High altitude areas in the Alps are characterised by the permafrost environment, which reacts sensitively to climate change. During the last decades several studies on alpine permafrost-related hazards have been performed, but few studies have focused on the geochemical content of the water that drains permafrost areas or outflow from rock glaciers (Williams et al., 2006; Thies et al., 2007; Krainer et al., 2011). Rock glaciers have physical and chemical influences on interflowing waters and their discharge can be highly enriched in solutes. For example, unexpected high nickel and manganese concentrations exceeding the EU limits for drinking water have been recently reported in some studies investigating rock glacier discharges (Ilyashuk et al., 2014). The present study aims to evaluate rock glacier solute fluxes into a high altitude lake in the Italian NW-Alps (Col d'Olen LTER site, Aosta Valley) in order to understand the impact of climate parameters on alpine permafrost, in particular the effects of permafrost ice melt on the water quality of mountain headwaters. This objective has been achieved through an integrated-multidisciplinary research programme involving climate analysis, rock glacier ground surface temperature investigation, water physiochemical and microbiological analyses. Nine automatic and three manned weather stations located in the surrounding areas of the rock glacier (radius: 12 km) have been used to study the relationships between climatic parameters and permafrost dynamics. Moreover, meteorological data have been collected by installing portable instruments in situ, integrated in a Mini Automatic Weather Station. To investigate the correlations between physiochemical features of water and the thermal state of the rock glacier surface, the ground temperature monitoring has been conducted. Temperature dataloggers have been buried 5/10 cm into the ground, regularly distributed on the rockglacier surface and in few surrounding sites. Total Station was used to achieve position for each datalogger and differential GNSS was used to acquire global geographic coordinates with centimetric precision in order to accurately interpolate ground temperature data grid. Water quality monitoring was conducted using a multiparameter spectrometer probe. In particular, NO3-Neq, DOCeq, TOCeq and turbidity were analysed, and UV-visible absorbance spectra (220-720 nm) were recorded every three hours during summer and early autumn seasons. Water sampling in the rock glacier lake (and related inflows) was conducted on weekly basis starting with the initiation of snow melt runoff until freeze-up in the early autumn. Moreover, the ablation water of the Indren Glacier (located in the study area) has been analysed in order to use it as reference data. Water samples have been analysed for anions, cations, trace elements, nutrient content (TOC, DOC, TDP, DOP, TDN, DON), EC (Electrical Conductivity), Eh (redox potential) and pH. Finally, in order to assess microbial diversity and abundance of communities, functionally related to ecosystem nutrient dynamics, diversity and abundance of microbial communities were analysed. The fine material in the permafrost feature has been characterised through the determination of Ntot, Corg, N forms and heavy metals.

  5. High resolution monitoring of hydrology and deformation in a unstable slope

    NASA Astrophysics Data System (ADS)

    Nevers, Pierre; Provost, Floriane; Kromer, Ryan; Bertrand, Catherine; Malet, Jean-Philippe; Marc, Vincent; Gaillardet, Jérôme; Gance, Julien; Abellan, Antonio; Jaboyedoff, Michel

    2017-04-01

    The Séchilienne landslide is located on the right bank of the Romanche River, South East of Grenoble (Isère, France). The active zone of the gravitational instability involves several millions of cubic meters. The geology consists in fractured hard rocks (micaschists) with double permeability and strong spatial heterogeneities. The deformation of the unstable slope is monitored by on-site extensometric gauges, inclinometers, GNSS and remotely by a terrestrial radar and a total station. Hydro-chemio-mechanical processes controlling the reactivation of the landslide are influenced by the evolution of the landslide deformation in space and time, and the water circulation in the highly heterogeneous fractured media. A hydrogeochemical monitoring of the unsaturated zone in the fractured hard rock has been carried out since 2010. This monitoring is supported by the French Landslide Observatory (OMIV) and consists in continuous measurements of physico-chemical parameters on two groundwater outlets (T°C, EC, flow rate) and weekly samplings of the waters for quality monitoring. Water chemistry is a good proxy to locate in time and space the origin of the infiltrated water. This tool is used to understand the complex relationships between chemical weathering, hydromechanical changes and weakening/deformation of the unstable material. This monitoring indicates a correlation between water chemistry, rainwater infiltration and rock mass deformation highlighting the impacts of rock-water interactions on the landslide dynamics. But a distributed information over area is still needed because the heterogeneities of the slope and the few sampling points currently prevent a detailed understanding of the global mechanisms involved. To better understand and constrain the hydrogeological and hydro-chemio-mechanical behavior of the slope, a multi-method monitoring of a flood wave infiltration has been carried out in early 2016 in order to distinguish possible signals related to significant displacements. Displacements were monitored by a GB-InSAR and a terrestrial laser scanner in order to obtain a global image of the deformation at high frequency (less than 1 hour). Repeated time-lapse geoelectrical profiles along four sections have been acquired each two hours on relevant plots which are suspected to be the main water flow paths from the surface to the depth. Water quality changes were monitored at high frequency in order to provide information on the water residence time. This first dataset gives insight into the moving volumes of rock and fluids. Imagery geophysics identifies a signal of fluid circulation in a fracture with a fast transit. The chemical signal identifies the heterogeneous functioning of the drainage system (drain/low permeable structure) with a fast transit.

  6. Numerical Simulation of HIWC Conditions with the Terminal Area Simulation System

    NASA Technical Reports Server (NTRS)

    Proctor, Fred H.; Switzer, George F.

    2016-01-01

    Three-dimensional, numerical simulation of a mesoconvective system is conducted in order to better understand conditions associated with High Ice Water Content (HIWC) and its threat to aviation safety. Although peak local values of ice water content may occur early in the storm lifetime, large areas of high concentrations expand with time and persist even when the storm tops begin to warm. The storm canopy which contains HIWC, has low radar reflectivity factor and is fed by an ensemble of regenerating thermal pulses.

  7. Local structure of dilute aqueous DMSO solutions, as seen from molecular dynamics simulations

    NASA Astrophysics Data System (ADS)

    Idrissi, Abdenacer; Marekha, Bogdan A.; Barj, Mohammed; Miannay, François Alexandre; Takamuku, Toshiyuki; Raptis, Vasilios; Samios, Jannis; Jedlovszky, Pál

    2017-06-01

    The information about the structure of dimethyl sulfoxide (DMSO)-water mixtures at relatively low DMSO mole fractions is an important step in order to understand their cryoprotective properties as well as the solvation process of proteins and amino acids. Classical MD simulations, using the potential model combination that best reproduces the free energy of mixing of these compounds, are used to analyze the local structure of DMSO-water mixtures at DMSO mole fractions below 0.2. Significant changes in the local structure of DMSO are observed around the DMSO mole fraction of 0.1. The array of evidence, based on the cluster and the metric and topological parameters of the Voronoi polyhedra distributions, indicates that these changes are associated with the simultaneous increase of the number of DMSO-water and decrease of water-water hydrogen bonds with increasing DMSO concentration. The inversion between the dominance of these two types of H-bonds occurs around XDMSO = 0.1, above which the DMSO-DMSO interactions also start playing an important role. In other words, below the DMSO mole fraction of 0.1, DMSO molecules are mainly solvated by water molecules, while above it, their solvation shell consists of a mixture of water and DMSO. The trigonal, tetrahedral, and trigonal bipyramidal distributions of water shift to lower corresponding order parameter values indicating the loosening of these orientations. Adding DMSO does not affect the hydrogen bonding between a reference water molecule and its first neighbor hydrogen bonded water molecules, while it increases the bent hydrogen bond geometry involving the second ones. The close-packed local structure of the third, fourth, and fifth water neighbors also is reinforced. In accordance with previous theoretical and experimental data, the hydrogen bonding between water and the first, the second, and the third DMSO neighbors is stronger than that with its corresponding water neighbors. At a given DMSO mole fraction, the behavior of the intensity of the high orientational order parameter values indicates that water molecules are more ordered in the vicinity of the hydrophilic group while their structure is close-packed near the hydrophobic group of DMSO.

  8. Search for the First-Order Liquid-to-Liquid Phase Transition in Low-Temperature Confined Water by Neutron Scattering

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

    Chen, Sow-Hsin; Wang, Zhe; Kolesnikov, Alexander I

    2013-01-01

    It has been conjectured that a 1st order liquid-to-liquid (L-L) phase transition (LLPT) between high density liquid (HDL) and low density liquid (LDL) in supercooled water may exist, as a thermodynamic extension to the liquid phase of the 1st order transition established between the two bulk solid phases of amorphous ice, the high density amorphous ice (HDA) and the low density amorphous ice (LDA). In this paper, we first recall our previous attempts to establish the existence of the 1st order L-L phase transition through the use of two neutron scattering techniques: a constant Q elastic diffraction study of isobaricmore » temperature scan of the D2O density, namely, the equation of state (EOS) measurements. A pronounced density hysteresis phenomenon in the temperature scan of the density above P = 1500 bar is observed which gives a plausible evidence of crossing the 1st order L-L phase transition line above this pressure; an incoherent quasi-elastic scattering measurements of temperature-dependence of the alpha-relaxation time of H2O at a series of pressures, namely, the study of the Fragile-to-Strong dynamic crossover (FSC) phenomenon as a function of pressure which we interpreted as the results of crossing the Widom line in the one-phase region. In this new experiment, we used incoherent inelastic neutron scattering (INS) to measure the density of states (DOS) of H atoms in H2O molecules in confined water as function of temperature and pressure, through which we may be able to follow the emergence of the LDL and HDL phases at supercooled temperature and high pressures. We here report for the first time the differences of librational and translational DOSs between the hypothetical HDL and LDL phases, which are similar to the corresponding differences between the well-established HDA and LDA ices. This is plausible evidence that the HDL and LDL phases are the thermodynamic extensions of the corresponding amorphous solid water HDA and LDA ices.« less

  9. Search for the first-order liquid-to-liquid phase transition in low-temperature confined water by neutron scattering

    NASA Astrophysics Data System (ADS)

    Chen, Sow-Hsin; Wang, Zhe; Kolesnikov, Alexander I.; Zhang, Yang; Liu, Kao-Hsiang

    2013-02-01

    It has been conjectured that a 1st order liquid-to-liquid (L-L) phase transition (LLPT) between high density liquid (HDL) and low density liquid (LDL) in supercooled water may exist, as a thermodynamic extension to the liquid phase of the 1st order transition established between the two bulk solid phases of amorphous ice, the high density amorphous ice (HDA) and the low density amorphous ice (LDA). In this paper, we first recall our previous attempts to establish the existence of the 1st order L-L phase transition through the use of two neutron scattering techniques: a constant Q elastic diffraction study of isobaric temperature scan of the D2O density, namely, the equation of state (EOS) measurements. A pronounced density hysteresis phenomenon in the temperature scan of the density above P = 1500 bar is observed which gives a plausible evidence of crossing the 1st order L-L phase transition line above this pressure; an incoherent quasi-elastic scattering measurements of temperature-dependence of the α-relaxation time of H2O at a series of pressures, namely, the study of the Fragile-to-Strong dynamic crossover (FSC) phenomenon as a function of pressure which we interpreted as the results of crossing the Widom line in the one-phase region. In this new experiment, we used incoherent inelastic neutron scattering (INS) to measure the density of states (DOS) of H atoms in H2O molecules in confined water as function of temperature and pressure, through which we may be able to follow the emergence of the LDL and HDL phases at supercooled temperature and high pressures. We here report for the first time the differences of librational and translational DOSs between the hypothetical HDL and LDL phases, which are similar to the corresponding differences between the well-established HDA and LDA ices. This is plausible evidence that the HDL and LDL phases are the thermodynamic extensions of the corresponding amorphous solid water HDA and LDA ices.

  10. Airborne Hydromapping - How high-resolution bathymetric surveys will change the research and work focused on waterbody-related topics

    NASA Astrophysics Data System (ADS)

    Steinbacher, Frank; Baran, Ramona; Dobler, Wolfgang; Aufleger, Markus

    2013-04-01

    Repetitive surveying of inshore waters and coastal zones is becoming more and more essential in order to evaluate water-level dynamics, structural and zonal variations of rivers and riparian areas, river degradation, water flow, reservoir sedimentation, delta growth, as well as coastal processes. This can only be achieved in an effective manner by employing hydrographic airborne laser scanning (hydromapping). A new laser scanner is introduced, which has been specifically designed for the acquisition of high-resolution hydrographic data in order to survey and monitor inland waters and shallow coastal zones. Recently, this scanner has been developed within the framework of an Austrian research cooperation between Riegl LMS and the Unit of Hydraulic Engineering at the University of Innsbruck. We present exemplary measurement results obtained with the compact airborne laser-scanning system during our project work. Along the Baltic Sea coast northeast of Kiel city, northern Germany, we obtained measurement depths up to 8 m under clear-water conditions. Moreover, we detect underwater dune-structures and the accumulation of sediment within groin structures. In contrast, under turbid water conditions we obtained depths of approximately 3 m along the Rhine River at Rheinfelden, German-Swiss border east of Basel city. Nevertheless, we were able to map small-scale and complex morphologic features within a fish ramp or bedrock cliffs. The laser data had been combined with sonar measurements displaying the bathymetry at depths of ca. 2-25 m in order to document comprehensively the actual hydrographic setting after the new construction of the hydropower plant Rheinfelden. In summary, a high-resolution spatial view on the ground of various waterbodies is now possible for the first time with point densities in the usual range of approximately 10-20 points/m². However, the combination of these data with high-resolution aerial (approximately < 5 cm/pixel) or spectral images offers a variety of new opportunities for further analysis. Lastly, the combined datasets - all of them captured during a single flight including topography, bathymetry, aerial and spectral pictures - provide a comprehensive and homogeneous database for the detailed and precise description of river- or coastal-bed hydraulic, morphologic and ecohydraulic processes. The high density and accuracy (less than 10 cm) of information offer the extended possibility for monitoring and supervisory purposes.

  11. Water quality at points-of-use in the Galapagos Islands.

    PubMed

    Gerhard, William A; Choi, Wan Suk; Houck, Kelly M; Stewart, Jill R

    2017-04-01

    Piped drinking water is often considered a gold standard for protecting public health but research is needed to explicitly evaluate the effect of centralized treatment systems on water quality in developing world settings. This study examined the effect of a new drinking water treatment plant (DWTP) on microbial drinking water quality at the point-of-use on San Cristobal Island, Galapagos using fecal indicator bacteria total coliforms and Escherichia coli. Samples were collected during six collection periods before and after operation of the DWTP began from the freshwater sources (n=4), the finished water (n=6), and 50 sites throughout the distribution system (n=287). This study found that there was a significant decrease in contamination by total coliforms (two orders of magnitude) and E. coli (one order of magnitude) after DWTP operation began (p<0.001). However, during at least one post-construction collection cycle, total coliforms and E. coli were still found at 66% and 28% of points-of-use (n=50), respectively. During the final collection period, conventional methods were augmented with human-specific Bacteroides assays - validated herein - with the goal of elucidating possible microbial contamination sources. Results show that E. coli contamination was not predictive of contamination by human wastes and suggests that observed indicator bacteria contamination may have environmental origins. Together these findings highlight the necessity of a holistic approach to drinking water infrastructure improvements in order to deliver high quality water through to the point-of-use. Copyright © 2017 Elsevier GmbH. All rights reserved.

  12. Conversion of deuterium gas to heavy water by catalytic isotopic exchange using wetproof catalyst

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

    Quaiattini, R.J.; McGauley, M.P.; Burns, D.L.

    The invention at Chalk River Nuclear Laboratories of a simple method of wetproofing platinum catalysts allows them to retain their activity in liquid water. High performance catalysts for the hydrogen-water isotope exchange reaction that remain active for years can now be routinely produced. The first commercial application using the ordered-bed-type wetproofed isotope exchange catalyst developed and patented by Atomic Energy of Canada Ltd. has been successfully completed. Approximately 9100 m/sup 3/ of deuterium gas stored at Brookhaven National Laboratory was converted to high grade heavy water. Conversion efficiency exceeded 99.8%. The product D/sub 2/O concentration was 6.7 percentage points highermore » than the feed D/sub 2/ gas.« less

  13. Mosquito larvicidal effectiveness of EcoBio-Block S: a novel integrated water-purifying concrete block formulation containing insect growth regulator pyriproxyfen.

    PubMed

    Kawada, Hitoshi; Saita, Susumu; Shimabukuro, Kozue; Hirano, Masachika; Koga, Masayuki; Iwashita, Toshiaki; Takagi, Masahiro

    2006-09-01

    EcoBio-Block S, a novel controlled release system (CRS) for the insect growth regulator pyriproxyfen, uses a water-purifying concrete block system (EcoBio-Block) composed of a porous volcanic rock and cement, and it incorporates the aerobic bacterial groups of Bacillus subtilis natto. EcoBio-Block S showed high inhibitory activity against mosquito emergence as well as a water-purifying effect. Chemical analysis and bioassay showed that EcoBio-Block S provides a high-performance CRS that controls the release of pyriproxyfen at low levels according to "zero order kinetics".

  14. Is a Cardio-Protective Diet Sustainable? A Review of the Synergies and Tensions Between Foods That Promote the Health of the Heart and the Planet.

    PubMed

    Downs, Shauna M; Fanzo, Jessica

    There are many synergies between a diet that is healthy for the heart and one that is healthy for the planet, but there may also be tensions. We examined the Barilla Center for Food and Nutrition's double pyramid to describe the carbon, water, and ecological footprints of the components of a cardio-protective diet. Overall, fruits, vegetables, and whole grains all tend to have low carbon and water footprints, while nuts and olive oil have relatively higher water footprints and fish have a high ecological footprint. In order to increase the sustainability of a cardio-protective diet, consumers can choose nuts (e.g., walnuts) and oils (e.g., sunflower) with lower water footprints and sustainably produced fish. However, in order to increase consumption of these foods, parallel efforts should be implemented targeting consumer knowledge and incentives to make these foods more affordable.

  15. Hierarchical nanoparticle assemblies formed by decorating breath figures.

    PubMed

    Böker, Alexander; Lin, Yao; Chiapperini, Kristen; Horowitz, Reina; Thompson, Mike; Carreon, Vincent; Xu, Ting; Abetz, Clarissa; Skaff, Habib; Dinsmore, A D; Emrick, Todd; Russell, Thomas P

    2004-05-01

    The combination of two self-assembly processes on different length scales leads to the formation of hierarchically structured nanoparticle arrays. Here, the formation of spherical cavities, or 'breath figures'-made by the condensation of micrometre-sized water droplets on the surface of a polymer solution-that self-assemble into a well-ordered hexagonal array, is combined with the self-assembly of CdSe nanoparticles at the polymer solution-water droplet interface. Complete evaporation of the solvent and water confines the particle assembly to an array of spherical cavities and allows for ex situ investigation. Fluorescence confocal, transmission electron and scanning electron microscope images show the preferential segregation of the CdSe nanoparticles to the polymer solution-water interface where they form a 5-7-nm-thick layer, thus functionalizing the walls of the holes. This process opens a new route to fabricating highly functionalized ordered microarrays of nanoparticles, potentially useful in sensory, separation membrane or catalytic applications.

  16. Distinct Interleaving of South China Sea Water and North Pacific Water During Impingements of Mesoscale Eddies on the Kuroshio

    NASA Astrophysics Data System (ADS)

    Wang, S. H.; Jan, S.

    2017-12-01

    In order to examine the water masses exchanges in and around the Kuroshio, hundreds of high-resolution hydrographic profiles (temperature, salinity and density) from the sea surface down to 1000 m depth acquired by a Seaglider across the Kuroshio off the southeast coast of Taiwan were analyzed. Hydrographic samplings at three different sections of a triangle glider track were conducted during 8 December 2016 and 6 March 2017 and each section was sampled repeatedly two times. Results from the observations reveal vigorous layered intrusions of the South China Sea Water coming from the northern South China Sea through the Luzon Strait to the North Pacific Water transported by the Kuroshio, resulting in the interleaving of the two water masses. The Diapycnal Spiciness Curvature (DSC) was used to characterize the magnitude of interleaving. The results indicate that significant interleaving mostly occurred in the intermediate layer between 400 m and 800 m, and the vertical and horizontal length scales were on the order of 10 m and 10 km, respectively. The Turner angle, which is a useful parameter for evaluating salt fingering and double diffusive processes, suggests that double diffusive is a dominant process in the interleaving regions. The associate estimation of eddy diffusivity for density is relatively high with a magnitude of O(10-3 m2 s-1) at depths between 600 m and 1000 m.

  17. Influence of Wetland and Channel Sediments on Strontium-90 Transport in the Borschi Stream, near Chernobyl

    NASA Astrophysics Data System (ADS)

    Freed, R.; Smith, L.; Bugai, D.

    2001-12-01

    In the Borschi watershed, 3 km south of the Chernobyl nuclear power plant, we have found the transfer of 90Sr in wetlands pore waters to surface waters and the subsequent flow of wetland surface waters to the stream, largely effect the concentration of 90Sr in the Borschi channel. In Borschi, we have observed that during most of the year, wetlands are the main source of 90Sr contributing to the Borschi stream and channel bottom sediments are a secondary source. Wetland pore waters have at least an order of magnitude higher concentration of 90Sr than all other surface and subsurface waters. Pore water data obtained using peepers shows the 90Sr diffusion gradient is high in near-surface wetland sediments while the 90Sr diffusion gradient is moderate to insignificant in near-surface channel sediments. Channel and wetland sediments are highly depleted in 90Sr compared with immobile nuclear fission products such as europium-154 and can account for all of the 90Sr removed by the stream since the accident. While channel sediments are largely depleted in exchangeable 90Sr, wetland sediments represent a large source of exchangeable 90Sr. Removal of 90Sr by the stream from the wetland and channel sediments is on the same order as mass loss by decay.

  18. Trends in Water Level and Flooding in Dhaka, Bangladesh and Their Impact on Mortality

    PubMed Central

    Thiele-Eich, Insa; Burkart, Katrin; Simmer, Clemens

    2015-01-01

    Climate change is expected to impact flooding in many highly populated coastal regions, including Dhaka (Bangladesh), which is currently among the fastest growing cities in the world. In the past, high mortality counts have been associated with extreme flood events. We first analyzed daily water levels of the past 100 years in order to detect potential shifts in extremes. A distributed lag non-linear model was then used to examine the connection between water levels and mortality. Results indicate that for the period of 2003–2007, which entails two major flood events in 2004 and 2007, high water levels do not lead to a significant increase in relative mortality, which indicates a good level of adaptation and capacity to cope with flooding. However, following low water levels, an increase in mortality could be found. As our trend analysis of past water levels shows that minimum water levels have decreased during the past 100 years, action should be taken to ensure that the exposed population is also well-adapted to drought. PMID:25648177

  19. Nonlinear vibrational spectroscopy of surfactants at liquid interfaces

    NASA Astrophysics Data System (ADS)

    Miranda, Paulo Barbeitas

    Surfactants are widely used to modify physical and chemical properties of interfaces. They play an important role in many technological problems. Surfactant monolayers are also of great scientific interest because they are two-dimensional systems that may exhibit a very rich phase transition behavior and can also be considered as a model system for biological interfaces. In this Thesis, we use a second-order nonlinear optical technique (Sum-Frequency Generation - SFG) to obtain vibrational spectra of surfactant monolayers at liquid/vapor and solid/liquid interfaces. The technique has several advantages: it is intrinsically surface-specific, can be applied to buried interfaces, has submonolayer sensitivity and is remarkably sensitive to the conformational order of surfactant monolayers. The first part of the Thesis is concerned with surfactant monolayers at the air/water interface (Langmuir films). Surface crystallization of an alcohol Langmuir film and of liquid alkanes are studied and their phase transition behaviors are found to be of different nature, although driven by similar intermolecular interactions. The effect of crystalline order of Langmuir monolayers on the interfacial water structure is also investigated. It is shown that water forms a well-ordered hydrogen-bonded network underneath an alcohol monolayer, in contrast to a fatty acid monolayer which induces a more disordered structure. In the latter case, ionization of the monolayer becomes more significant with increase of the water pH value, leading to an electric-field-induced ordering of interfacial water molecules. We also show that the orientation and conformation of fairly complicated molecules in a Langmuir monolayer can be completely mapped out using a combination of SFG and second harmonic generation (SHG). For a quantitative analysis of molecular orientation at an interface, local-field corrections must be included. The second part is a study of self-assembled surfactant monolayers at the solid/liquid interface. It is shown that the conformation of a monolayer adsorbed onto a solid substrate and immersed in a liquid is highly dependent on the monolayer surface density and on the nature of intermolecular interactions in the liquid. Fully packed monolayers are well ordered in any environment due to strong surfactant-surfactant interactions and limited liquid penetration into the monolayer. In contrast, loosely packed monolayers are very sensitive to the liquid environment. Non-polar liquids cause a mild increase in the surfactant conformational disorder. Polar liquids induce more disorder and hydrogen-bonding liquids produce highly disordered conformations due to the hydrophobic effect. When immersed in alkanes, under certain conditions the surfactant chains may become highly ordered due to their interaction with the liquid molecules (chain-chain interaction). In the case of long-chain alcohols, competition between the hydrophobic effect and chain-chain interaction is observed.

  20. Are extrusive rhyolites produced from permeable foam eruptions?

    USGS Publications Warehouse

    Friedman, I.

    1989-01-01

    The permeable foam hypothesis is suggested by Eichelberger el al. (1986) to explain a major loss of water from rhyolithic magmas in the volcanic conduit. Evidence for the high-water content of the major portion of the magmas is herein examined and rejected. Eichelberger's hypothesis does not take into account the large (~2 orders of magnitude) viscosity change that would occur in the conduit as a result of water loss. It also requires that the permeable foam collapse and weld to form an obsidian that in thin section displays no evidence of the foam. An alternate hypothesis to explain the existence of small amounts of high water content rhyolite glasses in acid volcanoes is that rhyolite magmas are relatively dry (0.1-0.3% H2O) and that water enters the magma from the environment to produce a water-rich selvage which then is kneaded into the body of the magma. -Author

  1. Significance of plasmalemma aquaporins for water-transport in Arabidopsis thaliana.

    PubMed

    Kaldenhoff, R; Grote, K; Zhu, J J; Zimmermann, U

    1998-04-01

    The plant plasma membrane intrinsic protein, PIP1b, facilitates water transport. These features were characterized in Xenopus oocytes and it has asked whether aquaporins are relevant for water transport in plants. In order to elucidate this uncertainty Arabidopsis thaliana was transformed with an anti-sense construct targeted to the PIP1b gene. Molecular analysis revealed that the anti-sense lines have reduced steady-state levels of PIP1b and the highly homologous PIP1a mRNA. The cell membrane water permeability was analyzed by swelling of protoplasts, which had been transferred into hypotonic conditions. The results indicate that the reduced expression of the specific aquaporins decreases the cellular osmotic water permeability coefficient approximately three times. The morphology and development of the anti-sense lines resembles that of control plants, with the exception of the root system, which is five times as abundant as that of control plants. Xylem pressure measurement suggests that the increase of root mass compensates the reduced cellular water permeability in order to ensure a sufficient water supply to the plant. The results obtained by this study, therefore, clearly demonstrate that aquaporins are important for plant water transport.

  2. Implementation of Collaborative Learning as a High-Impact Practice in a Natural Resources Management Section of Freshman Seminar

    ERIC Educational Resources Information Center

    McBroom, Matthew; Bullard, Steven; Kulhavy, David; Unger, Daniel

    2015-01-01

    Forestry and environmental science students enrolled in a one credit hour freshman seminar course participated in a land management evaluation and water quality sampling excursion using canoes and water sampling equipment. The purpose of this assessment was to engage students with hands-on, field based education in order to foster connections to…

  3. Development and Validation of a Fast Procedure to Analyze Amoxicillin in River Waters by Direct-Injection LC-MS/MS

    ERIC Educational Resources Information Center

    Homem, Vera; Alves, Arminda; Santos, Lu´cia

    2014-01-01

    A laboratory application with a strong component in analytical chemistry was designed for undergraduate students, in order to introduce a current problem in the environmental science field, the water contamination by antibiotics. Therefore, a simple and rapid method based on direct injection and high performance liquid chromatography-tandem mass…

  4. BLAM (Benthic Light Availability Model): A Proposed Model of Hydrogeomorphic Controls on Light in Rivers

    NASA Astrophysics Data System (ADS)

    Julian, J. P.; Doyle, M. W.; Stanley, E. H.

    2006-12-01

    Light is vital to the dynamics of aquatic ecosystems. It drives photosynthesis and photochemical reactions, affects thermal structure, and influences behavior of aquatic biota. Despite the fundamental role of light to riverine ecosystems, light studies in rivers have been mostly neglected because i) boundary conditions (e.g., banks, riparian vegetation) make ambient light measurements difficult, and ii) the optical water quality of rivers is highly variable and difficult to characterize. We propose a benthic light availability model (BLAM) that predicts the percent of incoming photosynthetically active radiation (PAR) available at the river bed. BLAM was developed by quantifying light attenuation of the five hydrogeomorphic controls that dictate riverine light availability: topography, riparian vegetation, channel geometry, optical water quality, and water depth. BLAM was calibrated using hydrogeomorphic data and light measurements from two rivers: Deep River - a 5th-order, turbid river in central North Carolina, and Big Spring Creek - a 2nd-order, optically clear stream in central Wisconsin. We used a series of four PAR sensors to measure i) above-canopy PAR, ii) PAR above water surface, iii) PAR below water surface, and iv) PAR on stream bed. These measurements were used to develop empirical light attenuation coefficients, which were then used in combination with optical water quality measurements, shading analyses, channel surveys, and flow records to quantify the spatial and temporal variability in riverine light availability. Finally, we apply BLAM to the Baraboo River - a 6th-order, 120-mile, unimpounded river in central Wisconsin - in order to characterize light availability along the river continuum (from headwaters to mouth).

  5. Sequence Dependencies of DNA Deformability and Hydration in the Minor Groove

    PubMed Central

    Yonetani, Yoshiteru; Kono, Hidetoshi

    2009-01-01

    Abstract DNA deformability and hydration are both sequence-dependent and are essential in specific DNA sequence recognition by proteins. However, the relationship between the two is not well understood. Here, systematic molecular dynamics simulations of 136 DNA sequences that differ from each other in their central tetramer revealed that sequence dependence of hydration is clearly correlated with that of deformability. We show that this correlation can be illustrated by four typical cases. Most rigid basepair steps are highly likely to form an ordered hydration pattern composed of one water molecule forming a bridge between the bases of distinct strands, but a few exceptions favor another ordered hydration composed of two water molecules forming such a bridge. Steps with medium deformability can display both of these hydration patterns with frequent transition. Highly flexible steps do not have any stable hydration pattern. A detailed picture of this correlation demonstrates that motions of hydration water molecules and DNA bases are tightly coupled with each other at the atomic level. These results contribute to our understanding of the entropic contribution from water molecules in protein or drug binding and could be applied for the purpose of predicting binding sites. PMID:19686662

  6. Evidence of low-density and high-density liquid phases and isochore end point for water confined to carbon nanotube

    PubMed Central

    Nomura, Kentaro; Kaneko, Toshihiro; Bai, Jaeil; Francisco, Joseph S.; Yasuoka, Kenji; Zeng, Xiao Cheng

    2017-01-01

    Possible transition between two phases of supercooled liquid water, namely the low- and high-density liquid water, has been only predicted to occur below 230 K from molecular dynamics (MD) simulation. However, such a phase transition cannot be detected in the laboratory because of the so-called “no-man’s land” under deeply supercooled condition, where only crystalline ices have been observed. Here, we show MD simulation evidence that, inside an isolated carbon nanotube (CNT) with a diameter of 1.25 nm, both low- and high-density liquid water states can be detected near ambient temperature and above ambient pressure. In the temperature–pressure phase diagram, the low- and high-density liquid water phases are separated by the hexagonal ice nanotube (hINT) phase, and the melting line terminates at the isochore end point near 292 K because of the retracting melting line from 292 to 278 K. Beyond the isochore end point (292 K), low- and high-density liquid becomes indistinguishable. When the pressure is increased from 10 to 600 MPa along the 280-K isotherm, we observe that water inside the 1.25-nm-diameter CNT can undergo low-density liquid to hINT to high-density liquid reentrant first-order transitions. PMID:28373562

  7. Water and solute permeability of rat lung caveolae: high permeabilities explained by acyl chain unsaturation.

    PubMed

    Hill, Warren G; Almasri, Eyad; Ruiz, W Giovanni; Apodaca, Gerard; Zeidel, Mark L

    2005-07-01

    Caveolae are invaginated membrane structures with high levels of cholesterol, sphingomyelin, and caveolin protein that are predicted to exist as liquid-ordered domains with low water permeability. We isolated a caveolae-enriched membrane fraction without detergents from rat lung and characterized its permeability properties to nonelectrolytes and protons. Membrane permeability to water was 2.85 +/- 0.41 x 10(-3) cm/s, a value 5-10 times higher than expected based on comparisons with other cholesterol and sphingolipid-enriched membranes. Permeabilities to urea, ammonia, and protons were measured and found to be moderately high for urea and ammonia at 8.85 +/- 2.40 x 10(-7)and 6.84 +/- 1.03 x 10(-2) respectively and high for protons at 8.84 +/- 3.06 x 10(-2) cm/s. To examine whether caveolin or other integral membrane proteins were responsible for high permeabilities, liposomes designed to mimic the lipids of the inner and outer leaflets of the caveolar membrane were made. Osmotic water permeability to both liposome compositions were determined and a combined inner/outer leaflet water permeability was calculated and found to be close to that of native caveolae at 1.58 +/- 1.1 x 10(-3) cm/s. In caveolae, activation energy for water flux was high (19.4 kcal/mol) and water permeability was not inhibited by HgCl2; however, aquaporin 1 was detectable by immunoblotting. Immunostaining of rat lung with AQP1 and caveolin antisera revealed very low levels of colocalization. We conclude that aquaporin water channels do not contribute significantly to the observed water flux and that caveolae have relatively high water and solute permeabilities due to the high degree of unsaturation in their fatty acyl chains.

  8. Application of multiple isotopic and geochemical tracers for investigation of recharge, salinization, and residence time of water in the Souss-Massa aquifer, southwest of Morocco

    USGS Publications Warehouse

    Bouchaou, L.; Michelot, J.L.; Vengosh, A.; Hsissou, Y.; Qurtobi, M.; Gaye, C.B.; Bullen, T.D.; Zuppi, G.M.

    2008-01-01

    Groundwater and surface water in Souss-Massa basin in the west-southern part of Morocco is characterized by a large variation in salinity, up to levels of 37 g L-1. The high salinity coupled with groundwater level decline pose serious problems for current irrigation and domestic water supplies as well as future exploitation. A combined hydrogeologic and isotopic investigation using several chemical and isotopic tracers such as Br/Cl, ??18O, ??2H, 3H, 87Sr/86Sr, ??11B, and 14C was carried out in order to determine the sources of water recharge to the aquifer, the origin of salinity, and the residence time of water. Stable isotope, 3H and 14C data indicate that the high Atlas mountains in the northern margin of the Souss-Massa basin with high rainfall and low ??18O and ??2H values (-6 to -8??? and -36 to -50???) is currently constitute the major source of recharge to the Souss-Massa shallow aquifer, particularly along the eastern part of the basin. Localized stable isotope enrichments offset meteoric isotopic signature and are associated with high nitrate concentrations, which infer water recycling via water agricultural return flows. The 3H and 14C data suggest that the residence time of water in the western part of the basin is in the order of several thousands of years; hence old water is mined, particularly in the coastal areas. The multiple isotope analyses and chemical tracing of groundwater from the basin reveal that seawater intrusion is just one of multiple salinity sources that affect the quality of groundwater in the Souss-Massa aquifer. We differentiate between modern seawater intrusion, salinization by remnants of seawater entrapped in the middle Souss plains, recharge of nitrate-rich agricultural return flow, and dissolution of evaporate rocks (gypsum and halite minerals) along the outcrops of the high Atlas mountains. The data generated in this study provide the framework for a comprehensive management plan in which water exploitation should shift toward the eastern part of the basin where current recharge occurs with young and high quality groundwater. In contrast, we argued that the heavily exploited aquifer along the coastal areas is more vulnerable given the relatively longer residence time of the water and salinization processes in this part of the aquifer. ?? 2008 Elsevier B.V. All rights reserved.

  9. Relationship between inferred redox potential of the depositional environment and geochemistry of the Upper Pennsylvanian (Missourian) Stark Shale Member of the Dennis Limestone, Wabaunsee County, Kansas, U.S.A.

    USGS Publications Warehouse

    Hatch, J.R.; Leventhal, J.S.

    1992-01-01

    Analyses of 21 samples collected from a core of the 52.8-cm-thick Stark Shale Member of the Dennis Limestone in Wabaunsee County, Kansas, demonstrate four cycles with two-orders-of-magnitude variations in contents of Cd, Mo, P, V and Zn, and order-of-magnitude variations in contents of organic carbon, Cr, Ni, Se and U. The observed variability in amounts and/or ratios of many metals and amounts and compositions of the organic matter appear related to the cause and degree of water-column stratification and the resulting absence/presence of dissolved O2 or H2S. High Cd, Mo, U, V, Zn and S contents, a high degree of pyritization (DOP) (0.75-0.88), and high high V (V + Ni) (0.84-0.89) indicate the presence of H2S in a strongly stratified water column. Intermediate contents of metals and S, intermediate DOP (0.67-0.75) and intermediate V (V + Ni) (054-0.82) indicate a less strongly stratified anoxic water column. Whereas, low metal contents and low V (V + Ni) (0.46-0.60) indicate a weakly stratified, dysoxic water column. High P contents at the top of the organic-matter-rich intervals within the Stark Shale Member indicate that phosphate precipitation was enhanced near the boundary between anoxic and dysoxic water compositions. Relatively abundant terrestrial organic matter in intervals deposited from the more strongly stratified H2S-bearing water column indicates a combined halocline-thermocline with the fresher near-surface water the transport mode for the terrestrial organic matter. The predominance of algal organic matter in intervals deposited from a less strongly stratified water column indicates the absence of the halocline and the presence of the more generally established thermocline. Relatively low amounts of degraded, hydrogen-poor organic matter characterize intervals deposited in a weakly stratified, dysoxic water column. The inferred variability in chemistry of the depositional environments may be related to climate variations and/or minor changes in sea level during the general phase of deeper water deposition responsible for this widespread shale member. ?? 1992.

  10. Microbial quality of water in dental unit waterlines.

    PubMed

    Nikaeen, Mahnaz; Hatamzadeh, Maryam; Sabzevari, Zohre; Zareh, Omolbanin

    2009-09-01

    Dental unit waterlines (DUWLs) are ideal environment for development of microbial biofilms. Microbial contamination of water in DUWLs is thought to be the result of biofilm formation as it could serves as a haven for pathogens. The aim of this study was to assess microbial quality of water in dental unit waterlines of dental units located at the dental school of Isfahan University of Medical Sciences. Water samples were collected from air/water syringe and high-speed handpiece. Generally, 100-200 ml water samples were collected aseptically in sterile containers with sodium thiosulfate at the beginning of the day after a 2 minute purge. Samples were transferred to the laboratory in insulated box with cooling packs and examined for total viable heterotrophic bacteria and fungi. The heterotrophic plate count levels were significantly exceeded the American Dental Association recommendations for DUWL water quality (< 200 CFU/ml), in both air/water syringe (84%, CFU/ml: 500-20000) and high-speed handpiece (96%, CFU/ml: 710-36800) samples. However, there was no significant difference between the level of contamination in the air/water syringe and high-speed handpiece. Fungi were found in 28% and 36% of air/water syringe and high-speed handpiece samples, respectively; and filamentous fungi were the most frequently isolated fungi. DUWLs should be subjected to routine microbial monitoring and to a decontamination protocol in order to minimize the risk of exposure to potential pathogens from dental units.

  11. “Nanofiltration” Enabled by Super-Absorbent Polymer Beads for Concentrating Microorganisms in Water Samples

    NASA Astrophysics Data System (ADS)

    Xie, Xing; Bahnemann, Janina; Wang, Siwen; Yang, Yang; Hoffmann, Michael R.

    2016-02-01

    Detection and quantification of pathogens in water is critical for the protection of human health and for drinking water safety and security. When the pathogen concentrations are low, large sample volumes (several liters) are needed to achieve reliable quantitative results. However, most microbial identification methods utilize relatively small sample volumes. As a consequence, a concentration step is often required to detect pathogens in natural waters. Herein, we introduce a novel water sample concentration method based on superabsorbent polymer (SAP) beads. When SAP beads swell with water, small molecules can be sorbed within the beads, but larger particles are excluded and, thus, concentrated in the residual non-sorbed water. To illustrate this approach, millimeter-sized poly(acrylamide-co-itaconic acid) (P(AM-co-IA)) beads are synthesized and successfully applied to concentrate water samples containing two model microorganisms: Escherichia coli and bacteriophage MS2. Experimental results indicate that the size of the water channel within water swollen P(AM-co-IA) hydrogel beads is on the order of several nanometers. The millimeter size coupled with a negative surface charge of the beads are shown to be critical in order to achieve high levels of concentration. This new concentration procedure is very fast, effective, scalable, and low-cost with no need for complex instrumentation.

  12. "Nanofiltration" Enabled by Super-Absorbent Polymer Beads for Concentrating Microorganisms in Water Samples.

    PubMed

    Xie, Xing; Bahnemann, Janina; Wang, Siwen; Yang, Yang; Hoffmann, Michael R

    2016-02-15

    Detection and quantification of pathogens in water is critical for the protection of human health and for drinking water safety and security. When the pathogen concentrations are low, large sample volumes (several liters) are needed to achieve reliable quantitative results. However, most microbial identification methods utilize relatively small sample volumes. As a consequence, a concentration step is often required to detect pathogens in natural waters. Herein, we introduce a novel water sample concentration method based on superabsorbent polymer (SAP) beads. When SAP beads swell with water, small molecules can be sorbed within the beads, but larger particles are excluded and, thus, concentrated in the residual non-sorbed water. To illustrate this approach, millimeter-sized poly(acrylamide-co-itaconic acid) (P(AM-co-IA)) beads are synthesized and successfully applied to concentrate water samples containing two model microorganisms: Escherichia coli and bacteriophage MS2. Experimental results indicate that the size of the water channel within water swollen P(AM-co-IA) hydrogel beads is on the order of several nanometers. The millimeter size coupled with a negative surface charge of the beads are shown to be critical in order to achieve high levels of concentration. This new concentration procedure is very fast, effective, scalable, and low-cost with no need for complex instrumentation.

  13. “Nanofiltration” Enabled by Super-Absorbent Polymer Beads for Concentrating Microorganisms in Water Samples

    PubMed Central

    Xie, Xing; Bahnemann, Janina; Wang, Siwen; Yang, Yang; Hoffmann, Michael R.

    2016-01-01

    Detection and quantification of pathogens in water is critical for the protection of human health and for drinking water safety and security. When the pathogen concentrations are low, large sample volumes (several liters) are needed to achieve reliable quantitative results. However, most microbial identification methods utilize relatively small sample volumes. As a consequence, a concentration step is often required to detect pathogens in natural waters. Herein, we introduce a novel water sample concentration method based on superabsorbent polymer (SAP) beads. When SAP beads swell with water, small molecules can be sorbed within the beads, but larger particles are excluded and, thus, concentrated in the residual non-sorbed water. To illustrate this approach, millimeter-sized poly(acrylamide-co-itaconic acid) (P(AM-co-IA)) beads are synthesized and successfully applied to concentrate water samples containing two model microorganisms: Escherichia coli and bacteriophage MS2. Experimental results indicate that the size of the water channel within water swollen P(AM-co-IA) hydrogel beads is on the order of several nanometers. The millimeter size coupled with a negative surface charge of the beads are shown to be critical in order to achieve high levels of concentration. This new concentration procedure is very fast, effective, scalable, and low-cost with no need for complex instrumentation. PMID:26876979

  14. Forecasting the Water Demand in Chongqing, China Using a Grey Prediction Model and Recommendations for the Sustainable Development of Urban Water Consumption.

    PubMed

    Wu, Hua'an; Zeng, Bo; Zhou, Meng

    2017-11-15

    High accuracy in water demand predictions is an important basis for the rational allocation of city water resources and forms the basis for sustainable urban development. The shortage of water resources in Chongqing, the youngest central municipality in Southwest China, has significantly increased with the population growth and rapid economic development. In this paper, a new grey water-forecasting model (GWFM) was built based on the data characteristics of water consumption. The parameter estimation and error checking methods of the GWFM model were investigated. Then, the GWFM model was employed to simulate the water demands of Chongqing from 2009 to 2015 and forecast it in 2016. The simulation and prediction errors of the GWFM model was checked, and the results show the GWFM model exhibits better simulation and prediction precisions than those of the classical Grey Model with one variable and single order equation GM(1,1) for short and the frequently-used Discrete Grey Model with one variable and single order equation, DGM(1,1) for short. Finally, the water demand in Chongqing from 2017 to 2022 was forecasted, and some corresponding control measures and recommendations were provided based on the prediction results to ensure a viable water supply and promote the sustainable development of the Chongqing economy.

  15. Determination of Germination Response to Temperature and Water Potential for a Wide Range of Cover Crop Species and Related Functional Groups

    PubMed Central

    Tribouillois, Hélène; Dürr, Carolyne; Demilly, Didier; Wagner, Marie-Hélène; Justes, Eric

    2016-01-01

    A wide range of species can be sown as cover crops during fallow periods to provide various ecosystem services. Plant establishment is a key stage, especially when sowing occurs in summer with high soil temperatures and low water availability. The aim of this study was to determine the response of germination to temperature and water potential for diverse cover crop species. Based on these characteristics, we developed contrasting functional groups that group species with the same germination ability, which may be useful to adapt species choice to climatic sowing conditions. Germination of 36 different species from six botanical families was measured in the laboratory at eight temperatures ranging from 4.5–43°C and at four water potentials. Final germination percentages, germination rate, cardinal temperatures, base temperature and base water potential were calculated for each species. Optimal temperatures varied from 21.3–37.2°C, maximum temperatures at which the species could germinate varied from 27.7–43.0°C and base water potentials varied from -0.1 to -2.6 MPa. Most cover crops were adapted to summer sowing with a relatively high mean optimal temperature for germination, but some Fabaceae species were more sensitive to high temperatures. Species mainly from Poaceae and Brassicaceae were the most resistant to water deficit and germinated under a low base water potential. Species were classified, independent of family, according to their ability to germinate under a range of temperatures and according to their base water potential in order to group species by functional germination groups. These groups may help in choosing the most adapted cover crop species to sow based on climatic conditions in order to favor plant establishment and the services provided by cover crops during fallow periods. Our data can also be useful as germination parameters in crop models to simulate the emergence of cover crops under different pedoclimatic conditions and crop management practices. PMID:27532825

  16. Toxic heavy metals in sediments, seawater, and molluscs in the eastern and western coastal waters of Guangdong Province, South China.

    PubMed

    Zhang, Ling; Shi, Zhen; Zhang, Jingping; Jiang, Zhijian; Wang, Fei; Huang, Xiaoping

    2016-05-01

    Heavy metal concentrations and distribution were studied in sediments, seawater, and molluscs, and the possible heavy metal sources in the coastal waters of Guangdong Province, South China were discussed. The results showed that the concentrations of Cu, Pb, Zn, and Cr in sediments in eastern coastal waters were generally higher than those in the western coastal waters. However, concentrations of most metals in seawater and molluscs in western waters were higher than in the eastern waters, which was tightly related to the local economics and urbanization development, especially, the different industrial structure in two regions. The main heavy metal sources were attributed to the industrial and agricultural effluent, domestic sewage, and even waste gas. Furthermore, heavy metal contamination assessment indicated that high contamination levels of Cd, Zn, and Pb occurred in sediments in local areas, especially in the bays and harbors. The metal accumulation levels by molluscs ranked following the order of Cd > Cu > As > Zn > Pb > Cr, and the ecological risks introduced by heavy metals in different areas were in the order of Zhanjiang > Yangmao > Shantou > Shanhui.

  17. Assessment of Service Life for Regenerative ECLSS Resin Beds

    NASA Technical Reports Server (NTRS)

    Cloud, Dale L.; Keilich, Maria C.; Polis, Peter C.; Yanczura, Stephen J.

    2013-01-01

    The International Space Station (ISS) Water Processor Assembly (WPA) and Oxygen Generation Assembly (OGA) manage and process water at various levels of cleanliness for multiple purposes. The effluent of theWPA and the influent of the OGA require water at very high levels of purity. The bulk of the water purification that occurs in both systems is performed by consumable activated carbon and ion exchange resin beds. Replacement beds must be available on orbit in order to continue the ISS critical processes of water purification and oxygen generation. Various hurdles exist in order to ensure viable spare resin beds. These include the characteristics of resin beds such as: storage environment, shelf life requirements, microbial growth, and variations in the levels and species of contaminants the beds are required to remove. Careful consideration has been given to match water models, bed capacities and spares traffic models to ensure that spares are always viable. The results of these studies and considerations, in particular, how shelf life requirements affect resin bed life management, are documented in this paper.

  18. Understanding how brass ball valves passing certification testing can cause elevated lead in water when installed.

    PubMed

    Triantafyllidou, Simoni; Raetz, Meredith; Parks, Jeffrey; Edwards, Marc

    2012-06-15

    The lead leaching potential of new brass plumbing devices has come under scrutiny as a significant source of lead in drinking water (>300 μg/L) of new buildings around the world. Experiments were conducted using ball valves that were sold as certified and known to have caused problems in practice, in order to better understand how installed products could create such problems, even if they passed "leaching tests" such as National Sanitation Foundation (NSF) Standard 61 Section 8. Diffusion of lead from within the device into water when installed can increase lead leaching by orders of magnitude relative to results of NSF testing, which once only required exposure of very small volumes of water within the device. "Normalization" of the lead-in-water result tended to produce estimates of lead concentration that were much lower than actual lead measured at the tap. Finally, the presence of flux could also dramatically increase lead leaching, whereas high water velocity had relatively little effect. Copyright © 2012. Published by Elsevier Ltd.

  19. Characterisation of boundary layer turbulent processes by the Raman lidar BASIL in the frame of HD(CP)2 Observational Prototype Experiment

    NASA Astrophysics Data System (ADS)

    Di Girolamo, Paolo; Cacciani, Marco; Summa, Donato; Scoccione, Andrea; De Rosa, Benedetto; Behrendt, Andreas; Wulfmeyer, Volker

    2017-01-01

    Measurements carried out by the University of Basilicata Raman lidar system (BASIL) are reported to demonstrate the capability of this instrument to characterise turbulent processes within the convective boundary layer (CBL). In order to resolve the vertical profiles of turbulent variables, high-resolution water vapour and temperature measurements, with a temporal resolution of 10 s and vertical resolutions of 90 and 30 m, respectively, are considered. Measurements of higher-order moments of the turbulent fluctuations of water vapour mixing ratio and temperature are obtained based on the application of autocovariance analyses to the water vapour mixing ratio and temperature time series. The algorithms are applied to a case study (11:30-13:30 UTC, 20 April 2013) from the High Definition Clouds and Precipitation for Climate Prediction (HD(CP)2) Observational Prototype Experiment (HOPE), held in western Germany in the spring 2013. A new correction scheme for the removal of the elastic signal crosstalk into the low quantum number rotational Raman signal is applied. The noise errors are small enough to derive up to fourth-order moments for both water vapour mixing ratio and temperature fluctuations.To the best of our knowledge, BASIL is the first Raman lidar with a demonstrated capability to simultaneously retrieve daytime profiles of water vapour turbulent fluctuations up to the fourth order throughout the atmospheric CBL. This is combined with the capability of measuring daytime profiles of temperature fluctuations up to the fourth order. These measurements, in combination with measurements from other lidar and in situ systems, are important for verifying and possibly improving turbulence and convection parameterisation in weather and climate models at different scales down to the grey zone (grid increment ˜ 1 km; Wulfmeyer et al., 2016).For the considered case study, which represents a well-mixed and quasi-stationary CBL, the mean boundary layer height is found to be 1290 ± 75 m above ground level (a.g.l.). Values of the integral scale for water vapour and temperature fluctuations at the top of the CBL are in the range of 70-125 and 75-225 s, respectively; these values are much larger than the temporal resolution of the measurements (10 s), which testifies that the temporal resolution considered for the measurements is sufficiently high to resolve turbulent processes down to the inertial subrange and, consequently, to resolve the major part of the turbulent fluctuations. Peak values of all moments are found in the interfacial layer in the proximity of the top of the CBL. Specifically, water vapour and temperature second-order moments (variance) have maximum values of 0.29 g2 kg-2 and 0.26 K2; water vapour and temperature third-order moments have peak values of 0.156 g3 kg-3 and -0.067 K3, while water vapour and temperature fourth-order moments have maximum values of 0.28 g4 kg-4 and 0.24 K4. Water vapour and temperature kurtosis have values of ˜ 3 in the upper portion of the CBL, which indicate normally distributed humidity and temperature fluctuations. Reported values of the higher-order moments are in good agreement with previous measurements at different locations, thus providing confidence in the possibility of using these measurements for turbulence parameterisation in weather and climate models.In the determination of the temperature profiles, particular care was dedicated to minimise potential effects associated with elastic signal crosstalk on the rotational Raman signals. For this purpose, a specific algorithm was defined and tested to identify and remove the elastic signal crosstalk and to assess the residual systematic uncertainty affecting temperature measurements after correction. The application of this approach confirms that, for the present Raman lidar system, the crosstalk factor remains constant with time; consequently an appropriate assessment of its constant value allows for a complete removal of the leaking elastic signal from the rotational Raman lidar signals at any time (with a residual error on temperature measurements after correction not exceeding 0.18 K).

  20. Forced intrusion of water and aqueous solutions in microporous materials: from fundamental thermodynamics to energy storage devices.

    PubMed

    Fraux, Guillaume; Coudert, François-Xavier; Boutin, Anne; Fuchs, Alain H

    2017-12-07

    We review the high pressure forced intrusion studies of water in hydrophobic microporous materials such as zeolites and MOFs, a field of research that has emerged some 15 years ago and is now very active. Many of these studies are aimed at investigating the possibility of using these systems as energy storage devices. A series of all-silica zeolites (zeosil) frameworks were found suitable for reversible energy storage because of their stability with respect to hydrolysis after several water intrusion-extrusion cycles. Several microporous hydrophobic zeolite imidazolate frameworks (ZIFs) also happen to be quite stable and resistant towards hydrolysis and thus seem very promising for energy storage applications. Replacing pure water by electrolyte aqueous solutions enables to increase the stored energy by a factor close to 3, on account of the high pressure shift of the intrusion transition. In addition to the fact that aqueous solutions and microporous silica materials are environmental friendly, these systems are thus becoming increasingly interesting for the design of new energy storage devices. This review also addresses the theoretical approaches and molecular simulations performed in order to better understand the experimental behavior of nano-confined water. Molecular simulation studies showed that water condensation takes place through a genuine first-order phase transition, provided that the interconnected pores structure is 3-dimensional and sufficiently open. In an extreme confinement situations such as in ferrierite zeosil, condensation seem to take place through a continuous supercritical crossing from a diluted to a dense fluid, on account of the fact that the first-order transition line is shifted to higher pressure, and the confined water critical point is correlatively shifted to lower temperature. These molecular simulation studies suggest that the most important features of the intrusion/extrusion process can be understood in terms of equilibrium thermodynamics considerations.

  1. Multilayer coatings for flexible high-barrier materials

    NASA Astrophysics Data System (ADS)

    Vaško, Karol; Noller, Klaus; Mikula, Milan; Amberg-Schwab, Sabine; Weber, Ulrike

    2009-06-01

    A multilayer, flexible, and transparent high-barrier system based on flexible plastic foils, polyethyleneterephthalate (PET) and ethylene-tetrafluoroethylene-copolymer (ETFE), combined with vacuum-deposited, inorganic SiOx layers and hybrid ORMOCER® varnish layers were prepared in different orders on a semiproduction level. Barrier properties of prepared systems, as water vapour transmission (WVTR) and oxygen transmission (OTR), were measured and studied in connection with surface energy, surface topography, and water vapour adsorption properties. Correlations among layers sequence, barrier properties, and other parameters are presented, including some basic principles of permeation of substances through multilayer barrier systems. A combination of several inorganic and hybrid varnish layers is necessary to achieve the technological demands from a barrier standpoint. It is easier to suppress the oxygen transport than the water transport, due to the additional active penetration of water through hydrogen bonds and silanol creations at oxide interfaces, capillary condensation, and swelling with high internal pressure, leading to new defects.

  2. Improving surface-subsurface water budgeting for Brownfield study sites using high resolution satellite imagery

    NASA Astrophysics Data System (ADS)

    Dujardin, J.; Boel, S.; Anibas, C.; Batelaan, O.; Canters, F.

    2009-04-01

    Countries around the world have problems with contaminated brownfield sites as resulting from a relatively anarchic economical and industrial development during the 19th and 20th centuries. Since a few decades policy makers and stakeholders have become more aware of the risk posed by these sites because some of these sites present direct public hazards. Water is often the main vector of the mobility of contaminants. In order to propose remediation measures for the contaminated sites, it is required to describe and to quantify as accurately as possible the surface and subsurface water fluxes in the polluted site. In this research a modelling approach with integrated remote sensing analysis has been developed for accurately calculating water and contaminant fluxes on the polluted sites. Groundwater pollution in urban environments is linked to patterns of land use, so to identify the sources of contamination with great accuracy in urban environments it is essential to characterize the land cover in a detailed way. The use of high resolution spatial information is required because of the complexity of the urban land use. An object-oriented classification approach applied on high resolution satellite data has been adopted. Cluster separability analysis and visual interpretation of the image objects belonging to each cluster resulted in the selection of 8 land-cover categories (water, bare soil, meadow, mixed forest, grey urban surfaces, red roofs, bright roofs and shadow).To assign the image objects to one of the 8 selected classes a multiple layer perceptron (MLP) approach was adopted, using the NeuralWorks Predict software. After a post-classification shadow removal and a rule-based classification enhancement a kappa-value of 0.86 was obtained. Once the land cover was characterized, the groundwater recharge has been simulated using the spatially distributed WetSpass model and the subsurface water flow was simulated with GMS 6.0 in order to identify and budget the water fluxes on the brownfield. The obtained land use map shows to have a strong impact on the groundwater recharge, resulting in a high spatial variability. Simulated groundwater fluxes from brownfield to a receiving river where independently verified by measurements and simulation of groundwater-surface water interaction based on thermal gradients in the river bed. It is concluded that in order to better quantify total fluxes of contaminants from brownfields in the groundwater, remote sensing imagery can be operationally integrated in a modelling procedure. The developed methodology is applied to a case site in Vilvoorde, Brussels (Belgium).

  3. Saving the Baltic Sea, the inland waters of its drainage basin, or both? spatial perspectives on reducing P-loads in eastern Sweden.

    PubMed

    Andersson, Ingela; Jarsjö, Jerker; Petersson, Mona

    2014-11-01

    Nutrient loads from inland sources to the Baltic Sea and adjacent inland waters need to be reduced in order to prevent eutrophication and meet requirements of the European Water Framework Directive (WFD) and the Baltic Sea Action Plan (BSAP). We here investigate the spatial implications of using different possible criteria for reducing water-borne phosphorous (P) loads in the Northern Baltic Sea River Basin District (NBS-RBD) in Sweden. Results show that most catchments that have a high degree of internal eutrophication do not express high export of P from their outlets. Furthermore, due to lake retention, lake catchments with high P-loads per agricultural area (which is potentially of concern for the WFD) did not considerably contribute to the P-loading of the Baltic Sea. Spatially uniform water quality goals may, therefore, not be effective in NBS-RBD, emphasizing more generally the need for regional adaptation of WFD and BSAP-related goals.

  4. A Novel Architecture for Carbon Nanotube Membranes towards Fast and Efficient Oil/water Separation.

    PubMed

    Saththasivam, Jayaprakash; Yiming, Wubulikasimu; Wang, Kui; Jin, Jian; Liu, Zhaoyang

    2018-05-09

    Carbon nanotubes (CNT) are robust and proven as promising building blocks for oil/water separating membranes. However, according to classic fluid dynamic theory, achieving high permeation flux without sacrificing other membrane properties is a formidable challenge for CNT membranes, because of the trade-off nature among key membrane parameters. Herein, to relieve the trade-off between permeation fluxes, oil rejection rate, and membrane thickness, we present a new concept to engineer CNT membranes with a three-dimensional (3D) architecture. Apart from achieving high oil separation efficiency (>99.9%), these new oil/water separating membranes can achieve water flux as high as 5,500 L/m 2 .h.bar, which is one order of magnitude higher than pristine CNT membranes. Most importantly, these outstanding properties can be achieved without drastically slashing membrane thickness down to nanoscale. The present study sheds a new light for the adoption of CNT-based membranes in oil/water separation industry.

  5. Using SRμCT to define water transport capacity in Picea abies

    NASA Astrophysics Data System (ADS)

    Lautner, Silke; Lenz, Claudia; Hammel, Jörg; Moosmann, Julian; Kühn, Michael; Caselle, Michele; Vogelgesang, Matthias; Kopmann, Andreas; Beckmann, Felix

    2017-10-01

    Water transport from roots to shoots is a vital necessity in trees in order to sustain their photosynthetic activity and, hence, their physiological activity. The vascular tissue in charge is the woody body of root, stem and branches. In gymnosperm trees, like spruce trees (Picea abies (L.) Karst.), vascular tissue consists of tracheids: elongated, protoplast- free cells with a rigid cell wall that allow for axial water transport via their lumina. In order to analyze the over-all water transport capacity within one growth ring, time-consuming light microscopy analysis of the woody sample still is the conventional approach for calculating tracheid lumen area. In our investigations at the Imaging Beamline (IBL) operated by the Helmholtz-Zentrum Geesthacht (HZG) at PETRA III storage ring of the Deutsches Elektronen-Synchrotron DESY, Hamburg, we applied SRμCT on small wood samples of spruce trees in order to visualize and analyze size and formation of xylem elements and their respective lumina. The selected high-resolution phase-contrast technique makes full use of the novel 20 MPixel CMOS area detector developed within the cooperation of HZG and the Karlsruhe data by light microscopy analysis and, hence, prove, that μCT is a most appropriate method to gain valid information on xylem cell structure and tree water transport capacity.

  6. Controllable Edge Oxidation and Bubbling Exfoliation Enable the Fabrication of High Quality Water Dispersible Graphene

    PubMed Central

    Tian, Suyun; Sun, Jing; Yang, Siwei; He, Peng; Wang, Gang; Di, Zengfeng; Ding, Guqiao; Xie, Xiaoming; Jiang, Mianheng

    2016-01-01

    Despite significant progresses made on mass production of chemically exfoliated graphene, the quality, cost and environmental friendliness remain major challenges for its market penetration. Here, we present a fast and green exfoliation strategy for large scale production of high quality water dispersible few layer graphene through a controllable edge oxidation and localized gas bubbling process. Mild edge oxidation guarantees that the pristine sp2 lattice is largely intact and the edges are functionalized with hydrophilic groups, giving rise to high conductivity and good water dispersibility at the same time. The aqueous concentration can be as high as 5.0 mg mL−1, which is an order of magnitude higher than previously reports. The water soluble graphene can be directly spray-coated on various substrates, and the back-gated field effect transistor give hole and electron mobility of ~496 and ~676 cm2 V−1 s−1, respectively. These results achieved are expected to expedite various applications of graphene. PMID:27666869

  7. Controllable Edge Oxidation and Bubbling Exfoliation Enable the Fabrication of High Quality Water Dispersible Graphene.

    PubMed

    Tian, Suyun; Sun, Jing; Yang, Siwei; He, Peng; Wang, Gang; Di, Zengfeng; Ding, Guqiao; Xie, Xiaoming; Jiang, Mianheng

    2016-09-26

    Despite significant progresses made on mass production of chemically exfoliated graphene, the quality, cost and environmental friendliness remain major challenges for its market penetration. Here, we present a fast and green exfoliation strategy for large scale production of high quality water dispersible few layer graphene through a controllable edge oxidation and localized gas bubbling process. Mild edge oxidation guarantees that the pristine sp 2 lattice is largely intact and the edges are functionalized with hydrophilic groups, giving rise to high conductivity and good water dispersibility at the same time. The aqueous concentration can be as high as 5.0 mg mL -1 , which is an order of magnitude higher than previously reports. The water soluble graphene can be directly spray-coated on various substrates, and the back-gated field effect transistor give hole and electron mobility of ~496 and ~676 cm 2 V -1 s -1 , respectively. These results achieved are expected to expedite various applications of graphene.

  8. Controllable Edge Oxidation and Bubbling Exfoliation Enable the Fabrication of High Quality Water Dispersible Graphene

    NASA Astrophysics Data System (ADS)

    Tian, Suyun; Sun, Jing; Yang, Siwei; He, Peng; Wang, Gang; di, Zengfeng; Ding, Guqiao; Xie, Xiaoming; Jiang, Mianheng

    2016-09-01

    Despite significant progresses made on mass production of chemically exfoliated graphene, the quality, cost and environmental friendliness remain major challenges for its market penetration. Here, we present a fast and green exfoliation strategy for large scale production of high quality water dispersible few layer graphene through a controllable edge oxidation and localized gas bubbling process. Mild edge oxidation guarantees that the pristine sp2 lattice is largely intact and the edges are functionalized with hydrophilic groups, giving rise to high conductivity and good water dispersibility at the same time. The aqueous concentration can be as high as 5.0 mg mL-1, which is an order of magnitude higher than previously reports. The water soluble graphene can be directly spray-coated on various substrates, and the back-gated field effect transistor give hole and electron mobility of ~496 and ~676 cm2 V-1 s-1, respectively. These results achieved are expected to expedite various applications of graphene.

  9. Behavioral Dynamics in Swimming: The Appropriate Use of Inertial Measurement Units.

    PubMed

    Guignard, Brice; Rouard, Annie; Chollet, Didier; Seifert, Ludovic

    2017-01-01

    Motor control in swimming can be analyzed using low- and high-order parameters of behavior. Low-order parameters generally refer to the superficial aspects of movement (i.e., position, velocity, acceleration), whereas high-order parameters capture the dynamics of movement coordination. To assess human aquatic behavior, both types have usually been investigated with multi-camera systems, as they offer high three-dimensional spatial accuracy. Research in ecological dynamics has shown that movement system variability can be viewed as a functional property of skilled performers, helping them adapt their movements to the surrounding constraints. Yet to determine the variability of swimming behavior, a large number of stroke cycles (i.e., inter-cyclic variability) has to be analyzed, which is impossible with camera-based systems as they simply record behaviors over restricted volumes of water. Inertial measurement units (IMUs) were designed to explore the parameters and variability of coordination dynamics. These light, transportable and easy-to-use devices offer new perspectives for swimming research because they can record low- to high-order behavioral parameters over long periods. We first review how the low-order behavioral parameters (i.e., speed, stroke length, stroke rate) of human aquatic locomotion and their variability can be assessed using IMUs. We then review the way high-order parameters are assessed and the adaptive role of movement and coordination variability in swimming. We give special focus to the circumstances in which determining the variability between stroke cycles provides insight into how behavior oscillates between stable and flexible states to functionally respond to environmental and task constraints. The last section of the review is dedicated to practical recommendations for coaches on using IMUs to monitor swimming performance. We therefore highlight the need for rigor in dealing with these sensors appropriately in water. We explain the fundamental and mandatory steps to follow for accurate results with IMUs, from data acquisition (e.g., waterproofing procedures) to interpretation (e.g., drift correction).

  10. Behavioral Dynamics in Swimming: The Appropriate Use of Inertial Measurement Units

    PubMed Central

    Guignard, Brice; Rouard, Annie; Chollet, Didier; Seifert, Ludovic

    2017-01-01

    Motor control in swimming can be analyzed using low- and high-order parameters of behavior. Low-order parameters generally refer to the superficial aspects of movement (i.e., position, velocity, acceleration), whereas high-order parameters capture the dynamics of movement coordination. To assess human aquatic behavior, both types have usually been investigated with multi-camera systems, as they offer high three-dimensional spatial accuracy. Research in ecological dynamics has shown that movement system variability can be viewed as a functional property of skilled performers, helping them adapt their movements to the surrounding constraints. Yet to determine the variability of swimming behavior, a large number of stroke cycles (i.e., inter-cyclic variability) has to be analyzed, which is impossible with camera-based systems as they simply record behaviors over restricted volumes of water. Inertial measurement units (IMUs) were designed to explore the parameters and variability of coordination dynamics. These light, transportable and easy-to-use devices offer new perspectives for swimming research because they can record low- to high-order behavioral parameters over long periods. We first review how the low-order behavioral parameters (i.e., speed, stroke length, stroke rate) of human aquatic locomotion and their variability can be assessed using IMUs. We then review the way high-order parameters are assessed and the adaptive role of movement and coordination variability in swimming. We give special focus to the circumstances in which determining the variability between stroke cycles provides insight into how behavior oscillates between stable and flexible states to functionally respond to environmental and task constraints. The last section of the review is dedicated to practical recommendations for coaches on using IMUs to monitor swimming performance. We therefore highlight the need for rigor in dealing with these sensors appropriately in water. We explain the fundamental and mandatory steps to follow for accurate results with IMUs, from data acquisition (e.g., waterproofing procedures) to interpretation (e.g., drift correction). PMID:28352243

  11. Natural clinoptilolite composite membranes on tubular stainless steel supports for water softening.

    PubMed

    Adamaref, Solmaz; An, Weizhu; Jarligo, Maria Ophelia; Kuznicki, Tetyana; Kuznicki, Steven M

    2014-01-01

    Disk membranes generated from high-purity natural clinoptilolite mineral rock have shown promising water desalination and de-oiling performance. In order to scale up production of these types of membranes for industrial wastewater treatment applications, a coating strategy was devised. A composite mixture of natural clinoptilolite from St. Cloud (Winston, NM, USA) and aluminum phosphate was deposited on the inner surface of porous stainless steel tubes by the slip casting technique. The commercial porous stainless steel tubes were pre-coated with a TiO2 layer of about 10 μm. Phase composition and morphology of the coating materials were investigated using X-ray diffraction and scanning electron microscopy. Water softening performance of the fabricated membranes was evaluated using Edmonton (Alberta, Canada) municipal tap water as feed source. Preliminary experimental results show a high water flux of 7.7 kg/(m(2) h) and 75% reduction of hardness and conductivity in a once-through membrane process at 95 °C and feed pressure of 780 kPa. These results show that natural zeolite coated, stainless steel tubular membranes have high potential for large-scale purification of oil sands steam-assisted gravity drainage water at high temperature and pressure requirements.

  12. Nano-electro-mechanical pump: Giant pumping of water in carbon nanotubes

    PubMed Central

    Farimani, Amir Barati; Heiranian, Mohammad; Aluru, Narayana R.

    2016-01-01

    A fully controllable nano-electro-mechanical device that can pump fluids at nanoscale is proposed. Using molecular dynamics simulations, we show that an applied electric field to an ion@C60 inside a water-filled carbon nanotube can pump water with excellent efficiency. The key physical mechanism governing the fluid pumping is the conversion of electrical energy into hydrodynamic flow with efficiencies as high as 64%. Our results show that water can be compressed up to 7% higher than its bulk value by applying electric fields. High flux of water (up to 13,000 molecules/ns) is obtained by the electro-mechanical, piston-cylinder-like moving mechanism of the ion@C60 in the CNT. This large flux results from the piston-like mechanism, compressibility of water (increase in density of water due to molecular ordering), orienting dipole along the electric field and efficient electrical to mechanical energy conversion. Our findings can pave the way towards efficient energy conversion, pumping of fluids at nanoscale, and drug delivery. PMID:27193507

  13. Nano-electro-mechanical pump: Giant pumping of water in carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Farimani, Amir Barati; Heiranian, Mohammad; Aluru, Narayana R.

    2016-05-01

    A fully controllable nano-electro-mechanical device that can pump fluids at nanoscale is proposed. Using molecular dynamics simulations, we show that an applied electric field to an ion@C60 inside a water-filled carbon nanotube can pump water with excellent efficiency. The key physical mechanism governing the fluid pumping is the conversion of electrical energy into hydrodynamic flow with efficiencies as high as 64%. Our results show that water can be compressed up to 7% higher than its bulk value by applying electric fields. High flux of water (up to 13,000 molecules/ns) is obtained by the electro-mechanical, piston-cylinder-like moving mechanism of the ion@C60 in the CNT. This large flux results from the piston-like mechanism, compressibility of water (increase in density of water due to molecular ordering), orienting dipole along the electric field and efficient electrical to mechanical energy conversion. Our findings can pave the way towards efficient energy conversion, pumping of fluids at nanoscale, and drug delivery.

  14. Nano-electro-mechanical pump: Giant pumping of water in carbon nanotubes.

    PubMed

    Farimani, Amir Barati; Heiranian, Mohammad; Aluru, Narayana R

    2016-05-19

    A fully controllable nano-electro-mechanical device that can pump fluids at nanoscale is proposed. Using molecular dynamics simulations, we show that an applied electric field to an ion@C60 inside a water-filled carbon nanotube can pump water with excellent efficiency. The key physical mechanism governing the fluid pumping is the conversion of electrical energy into hydrodynamic flow with efficiencies as high as 64%. Our results show that water can be compressed up to 7% higher than its bulk value by applying electric fields. High flux of water (up to 13,000 molecules/ns) is obtained by the electro-mechanical, piston-cylinder-like moving mechanism of the ion@C60 in the CNT. This large flux results from the piston-like mechanism, compressibility of water (increase in density of water due to molecular ordering), orienting dipole along the electric field and efficient electrical to mechanical energy conversion. Our findings can pave the way towards efficient energy conversion, pumping of fluids at nanoscale, and drug delivery.

  15. Superhydrophobic silica wool—a facile route to separating oil and hydrophobic solvents from water

    NASA Astrophysics Data System (ADS)

    Crick, Colin R.; Bhachu, Davinder S.; Parkin, Ivan P.

    2014-12-01

    Silica microfiber wool was systematically functionalized in order to provide an extremely water repellent and oleophilic material. This was carried out using a two-step functionalization that was shown to be a highly effective method for generating an intense water repulsion and attraction for oil. A demonstration of the silica wools application is shown through the highly efficient separation of oils and hydrophobic solvents from water. Water is confined to the extremities of the material, while oil is absorbed into the voids within the wool. The effect of surface functionalization is monitored though observing the interaction of the material with both oils and water, in addition to scanning electron microscope images, x-ray photoelectron spectroscopy and energy dispersive x-ray analysis. The material can be readily utilized in many applications, including the cleaning of oil spills and filtering during industrial processes, as well as further water purification tasks—while not suffering the losses of efficiency observed in current leading polymeric materials.

  16. Ozone Application for Tofu Waste Water Treatment and Its Utilisation for Growth Medium of Microalgae Spirulina sp

    NASA Astrophysics Data System (ADS)

    Hadiyanto, Hadiyanto

    2018-02-01

    Tofu industries produce waste water containing high organic contents and suspendid solid which is harmful if directly discharged to the environment. This waste can lead to disruption of water quality and lowering the environmental carrying capacity of waters around the tofu industries. Besides, the tofu waste water still contains high nitrogen contents which can be used for microalgae growth. This study was aimed to reduce the pollution load (chemical oxygen demand-COD) of tofue wastewater by using ozone treatments and to utilize nutrients in treated tofu waste water as medium growth of microalgae. The result showed that the reduction of COD by implementation of ozone treatment followed first order kinetic. Under variation of waste concentrations between 10-40%, the degradation rate constant was in the range of 0.00237-0.0149 min-1. The microalgae was able to grow in the tofue waste medium by the growth rate constants of 0.15-0.29 day-1. This study concluded that tofu waste was highly potent for microalgae growth.

  17. Compilation of regional ground water monitoring data to investigate 60 years of ground water dynamics in New England

    NASA Astrophysics Data System (ADS)

    Boutt, D. F.; Weider, K. M.

    2010-12-01

    Theory suggests that ground water systems at shallow depths are sensitive to climate system dynamics but respond at differing rates due to primarily hydrogeologic characteristics of the aquifer. These rates are presumably to a first order controlled by the transmissivity and hydrogeologic settings of aquifer systems. Regional scale modeling and understanding of the impact of this behavior is complicated by the fact that aquifer systems in glaciated regions of the North American continent often possess high degrees of heterogeneity as well as disparate hydraulic connections between aquifer systems. In order to investigate these relationships we present the results of a regional compilation of groundwater hydraulic head data across the New England states together with corresponding atmospheric (precipitation and temperature) and streamflow data for a 60 year period (1950-2010). Ground water trends are calculated as normalized anomalies, and analyzed with respect to regional compiled precipitation, temperature, and streamflow. Anomalies in ground water levels are analyzed together with hydrogeologic variables such as aquifer thickness, topographic setting, and distance from coast. The time-series display decadal patterns with ground water levels being highly variable and lagging that of precipitation and streamflow pointing to site specific and non-linear response to changes in climate. Sites with deeper water tables respond slower and with larger anomalies compared to shallow water table sites. Tills consistently respond quicker and have larger anomalies compared to outwash and stratified glacial deposits. The data set suggests that while regional patterns in ground water table response are internally consistent, the magnitude and timing of the response to wet or dry periods is extremely sensitive to hydrogeologic characteristics of the host aquifer.

  18. Ice polyamorphism in the minimal Mercedes-Benz model of water.

    PubMed

    Cartwright, Julyan H E; Piro, Oreste; Sánchez, Pedro A; Sintes, Tomás

    2012-12-28

    We investigate ice polyamorphism in the context of the two-dimensional Mercedes-Benz model of water. We find a first-order phase transition between a crystalline phase and a high-density amorphous phase. Furthermore, we find a reversible transformation between two amorphous structures of high and low density; however, we find this to be a continuous and not an abrupt transition, as the low-density amorphous phase does not show structural stability. We discuss the origin of this behavior and its implications with regard to the minimal generic modeling of polyamorphism.

  19. Ice polyamorphism in the minimal Mercedes-Benz model of water

    NASA Astrophysics Data System (ADS)

    Cartwright, Julyan H. E.; Piro, Oreste; Sánchez, Pedro A.; Sintes, Tomás

    2012-12-01

    We investigate ice polyamorphism in the context of the two-dimensional Mercedes-Benz model of water. We find a first-order phase transition between a crystalline phase and a high-density amorphous phase. Furthermore, we find a reversible transformation between two amorphous structures of high and low density; however, we find this to be a continuous and not an abrupt transition, as the low-density amorphous phase does not show structural stability. We discuss the origin of this behavior and its implications with regard to the minimal generic modeling of polyamorphism.

  20. Inactivation of Escherichia coli in water by pulsed dielectric barrier discharge in coaxial reactor.

    PubMed

    Hernández-Arias, A N; Rodríguez-Méndez, B G; López-Callejas, R; Alcántara-Díaz, D; Valencia-Alvarado, R; Mercado-Cabrera, A; Peña-Eguiluz, R; Muñoz-Castro, A E; Barocio, S R; de la Piedad-Beneitez, A

    2012-09-01

    An experimental study of ATCC (American Type Culture Collection) 8739 Escherichia coli bacteria inactivation in water by means of pulsed dielectric barrier discharge (PDBD) atmospheric pressure plasmas is presented. Plasma is generated by an adjustable power source capable of supplying high voltage 25 kV pulses, ∼30 μs long and at a 500 Hz frequency. The process was conducted in a ∼152 cm(3) cylindrical stainless steel coaxial reactor, endowed with a straight central electrode and a gas inlet. The bacterial concentration in water was varied from 10(3) up to 10(8) E. coli cells per millilitre. The inactivation was achieved without gas flow in the order of 82% at 10(8) colony-forming units per millilitre (CFU mL(-1)) concentrations in 600 s. In addition, oxygen was added to the gas supply in order to increase the ozone content in the process, raising the inactivation percentage to the order of 90% in the same treatment time. In order to reach a higher efficiency however, oxygen injection modulation is applied, leading to inactivation percentages above 99.99%. These results are similarly valid for lower bacterial concentrations.

  1. A symmetric, triply interlaced 3-D anionic MOF that exhibits both magnetic order and SMM behaviour.

    PubMed

    Campo, J; Falvello, L R; Forcén-Vázquez, E; Sáenz de Pipaón, C; Palacio, F; Tomás, M

    2016-11-14

    A newly prepared 3-D polymer of cobalt citrate cubanes bridged by high-spin Co(ii) centres displays both single-molecule magnet (SMM) behaviour and magnetic ordering. Triple interpenetration of the 3-D diamondoid polymers yields a crystalline solid with channels that host cations and free water molecules, with the SMM behaviour of the Co 4 O 4 cores preserved. The octahedrally coordinated Co(ii) bridges are implicated in the onset of magnetic order at an experimentally accessible temperature.

  2. Evidence for the existence of Persian Gulf Water and Red Sea Water in the Bay of Bengal

    NASA Astrophysics Data System (ADS)

    Jain, Vineet; Shankar, D.; Vinayachandran, P. N.; Kankonkar, A.; Chatterjee, Abhisek; Amol, P.; Almeida, A. M.; Michael, G. S.; Mukherjee, A.; Chatterjee, Meenakshi; Fernandes, R.; Luis, R.; Kamble, Amol; Hegde, A. K.; Chatterjee, Siddhartha; Das, Umasankar; Neema, C. P.

    2017-05-01

    The high-salinity water masses that originate in the North Indian Ocean are Arabian Sea High-Salinity Water (ASHSW), Persian Gulf Water (PGW), and Red Sea Water (RSW). Among them, only ASHSW has been shown to exist in the Bay of Bengal. We use CTD data from recent cruises to show that PGW and RSW also exist in the bay. The presence of RSW is marked by a deviation of the salinity vertical profile from a fitted curve at depths ranging from 500 to 1000 m; this deviation, though small (of the order of 0.005 psu and therefore comparable to the CTD accuracy of 0.003 psu), is an order of magnitude larger than the 0.0003 psu fluctuations associated with the background turbulence or instrument noise in this depth regime, allowing us to infer the existence of RSW throughout the bay. PGW is marked by the presence of a salinity maximum at 200-450 m; in the southwestern bay, PGW can be distinguished from the salinity maximum due to ASHSW because of the intervening Arabian Sea Salinity Minimum. This salinity minimum and the maximum associated with ASHSW disappear east and north of the south-central bay (85°E, 8°N) owing to mixing between the fresher surface waters that are native to the bay (Bay of Bengal Water or BBW) with the high-salinity ASHSW. Hence, ASHSW is not seen as a distinct water mass in the northern and eastern bay and the maximum salinity over most of the bay is associated with PGW. The surface water over most of the bay is therefore a mixture of ASHSW and the low-salinity BBW. As a corollary, we can also infer that the weak oxygen peak seen within the oxygen-minimum zone in the bay at a depth of 250-400 m is associated with PGW. The hydrographic data also show that these three high-salinity water masses are advected into the bay by the Summer Monsoon Current, which is seen to be a deep current extending to 1000 m. These deep currents extend into the northern bay as well, providing a mechanism for spreading ASHSW, PGW, and RSW throughout the bay.

  3. New gentle-wing high-shear granulator: impact of processing variables on granules and tablets characteristics of high-drug loading formulation using design of experiment approach.

    PubMed

    Fayed, Mohamed H; Abdel-Rahman, Sayed I; Alanazi, Fars K; Ahmed, Mahrous O; Tawfeek, Hesham M; Al-Shdefat, Ramadan I

    2017-10-01

    The aim of this work was to study the application of design of experiment (DoE) approach in defining design space for granulation and tableting processes using a novel gentle-wing high-shear granulator. According to quality-by-design (QbD) prospective, critical attributes of granules, and tablets should be ensured by manufacturing process design. A face-centered central composite design has been employed in order to investigate the effect of water amount (X 1 ), impeller speed (X 2 ), wet massing time (X 3 ), and water addition rate (X 4 ) as independent process variables on granules and tablets characteristics. Acetaminophen was used as a model drug and granulation experiments were carried out using dry addition of povidone k30. The dried granules have been analyzed for their size distribution, density, and flow pattern. Additionally, the produced tablets have been investigated for; weight uniformity, breaking force, friability and percent capping, disintegration time, and drug dissolution. Results of regression analysis showed that water amount, impeller speed and wet massing time have significant (p < .05) effect on granules and tablets characteristics. However, the water amount had the most pronounced effect as indicated by its higher parameter estimate. On the other hand, water addition rate showed a minimal impact on granules and tablets properties. In conclusion, water amount, impeller speed, and wet massing time could be considered as critical process variables. Thus, understanding the relationship between these variables and quality attributes of granules and corresponding tablets provides the basis for adjusting granulation variables in order to optimize product performance.

  4. Elevated temperature drives kelp microbiome dysbiosis, while elevated carbon dioxide induces water microbiome disruption

    PubMed Central

    Morris, Megan M.; Brown, Matt; Doane, Michael; Edwards, Matthew S.; Michael, Todd P.; Dinsdale, Elizabeth A.

    2018-01-01

    Global climate change includes rising temperatures and increased pCO2 concentrations in the ocean, with potential deleterious impacts on marine organisms. In this case study we conducted a four-week climate change incubation experiment, and tested the independent and combined effects of increased temperature and partial pressure of carbon dioxide (pCO2), on the microbiomes of a foundation species, the giant kelp Macrocystis pyrifera, and the surrounding water column. The water and kelp microbiome responded differently to each of the climate stressors. In the water microbiome, each condition caused an increase in a distinct microbial order, whereas the kelp microbiome exhibited a reduction in the dominant kelp-associated order, Alteromondales. The water column microbiomes were most disrupted by elevated pCO2, with a 7.3 fold increase in Rhizobiales. The kelp microbiome was most influenced by elevated temperature and elevated temperature in combination with elevated pCO2. Kelp growth was negatively associated with elevated temperature, and the kelp microbiome showed a 5.3 fold increase Flavobacteriales and a 2.2 fold increase alginate degrading enzymes and sulfated polysaccharides. In contrast, kelp growth was positively associated with the combination of high temperature and high pCO2 ‘future conditions’, with a 12.5 fold increase in Planctomycetales and 4.8 fold increase in Rhodobacteriales. Therefore, the water and kelp microbiomes acted as distinct communities, where the kelp was stabilizing the microbiome under changing pCO2 conditions, but lost control at high temperature. Under future conditions, a new equilibrium between the kelp and the microbiome was potentially reached, where the kelp grew rapidly and the commensal microbes responded to an increase in mucus production. PMID:29474389

  5. Solid anaerobic digestion: State-of-art, scientific and technological hurdles.

    PubMed

    André, Laura; Pauss, André; Ribeiro, Thierry

    2018-01-01

    In this paper, a state-of-art about solid anaerobic digestion (AD), focused on recent progress and trends of research is proposed. Solid anaerobic digestion should be the most appropriate process for degradation of by-products with high total solid (TS) content, especially lignocellulosic materials like agricultural waste (straw, manure), household waste and food waste. Solid AD is already widely used in waste water treatment plant for treating plant for sewage sludge but could be more developed for lignocellulosic materials with high TS content. Many research works were carried out in Europe on solid AD, focused on current hurdles (BMP, codigestion, inhibition, microbial population, rheology, water transfers, inoculum, etc.) in order to optimize the solid AD process. In conclusion, hurdles of solid AD process should and must be solved in order to propose better productivity and profitability of such system operating with high TS content (>15%), favouring reliable industrial processes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Aqueous Rare Earth Element Patterns and Concentration in Thermal Brines Associated With Oil and Gas Production

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

    Nye, Charles; Quillinan, Scott Austin; Neupane, Ghanashyam

    This study is part of a joint effort by the University of Wyoming (UW) School of Energy Resources (SER), the UW Engineering Department, Idaho National Laboratories (INL), and the United States Geological Survey (USGS) to describe rare earth element concentrations in oil and gas produced waters and in coal-fired power station ash ponds. In this work we present rare earth element (REE) and trace metal behavior in produced water from four Wyoming oil and gas fields and surface ash pond water from two coal-fired power stations. The concentration of REEs in oil and gas produced waters is largely unknown. Formore » example, of the 150,000 entries in the USGS National Produced Waters Geochemical Database less than 5 include data for REEs. Part of the reason for this scarcity is the analytical challenge of measuring REEs in high salinity, hydrocarbon-bearing waters. The industry standard for water analysis struggles to detect REEs in natural waters under ideal conditions. The detection of REEs in oil and gas field samples becomes all but impossible with the background noise and interferences caused by high concentrations of non-REE ions and residual hydrocarbons. The INL team members have overcome many of these challenges (e.g. McLing, 2014), and continue to develop their methods. Using the methods of the INL team members we measured REEs in high salinity oil and gas produced waters. Our results show that REEs exist as a dissolved species in all waters measured for this project, typically within the parts per trillion range. The samples may be grouped into two broad categories analytically, and these categories match their genesis: Wyoming oil and gas brines contain elevated levels of Europium, and Wyoming industrial pond waters show elevation in heavy REEs (HREEs). While broadly true, important variations exist within both groups. In the same field Europium can vary by more than an order of magnitude, and likewise HREEs in industrial ponds at the same site can vary by more than an order of magnitude. Future work will investigate the reasons for these variations.« less

  7. Laboratory measurements of physical, chemical, and optical characteristics of Lake Chicot sediment waters

    NASA Technical Reports Server (NTRS)

    Witte, W. G.; Whitlock, C. H.; Usry, J. W.; Morris, W. D.; Gurganus, E. A.

    1981-01-01

    Reflectance, chromaticity, diffuse attenuation, beam attenuation, and several other physical and chemical properties were measured for various water mixtures of lake bottom sediment. Mixture concentrations range from 5 ppm to 700 ppm by weight of total suspended solids in filtered deionized tap water. Upwelled reflectance is a nonlinear function of remote sensing wave lengths. Near-infrared wavelengths are useful for monitoring highly turbid waters with sediment concentrations above 100 ppm. It is found that both visible and near infrared wavelengths, beam attenuation correlates well with total suspended solids ranging over two orders of magnitude.

  8. Design of a New Water Load for S-band 750 kW Continuous Wave High Power Klystron Used in EAST Tokamak

    NASA Astrophysics Data System (ADS)

    Liu, Liang; Liu, Fukun; Shan, Jiafang; Kuang, Guangli

    2007-04-01

    In order to test the klystrons operated at a frequency of 3.7 GHz in a continuous wave (CW) mode, a type of water load to absorb its power up to 750 kW is presented. The distilled water sealed with an RF ceramic window is used as the absorbent. At a frequency range of 70 MHz, the VSWR (Voltage Standing Wave Ratio) is below 1.2, and the rise in temperature of water is about 30 oC at the highest power level.

  9. Two-Dimensional Wetting of a Stepped Copper Surface

    NASA Astrophysics Data System (ADS)

    Lin, C.; Avidor, N.; Corem, G.; Godsi, O.; Alexandrowicz, G.; Darling, G. R.; Hodgson, A.

    2018-02-01

    Highly corrugated, stepped surfaces present regular 1D arrays of binding sites, creating a complex, heterogeneous environment to water. Rather than decorating the hydrophilic step sites to form 1D chains, water on stepped Cu(511) forms an extended 2D network that binds strongly to the steps but bridges across the intervening hydrophobic Cu(100) terraces. The hydrogen-bonded network contains pentamer, hexamer, and octomer water rings that leave a third of the stable Cu step sites unoccupied in order to bind water H down close to the step dipole and complete three hydrogen bonds per molecule.

  10. Rheology of water and ammonia-water ices

    NASA Technical Reports Server (NTRS)

    Goldsby, D. L.; Kohlstedt, D. L.; Durham, W. B.

    1993-01-01

    Creep experiments on fine-grained water and ammonia-water ices have been performed at one atmosphere and high confining pressure in order to develop constitutive relationships necessary to model tectonic processes and interpret surface features of icy moons of the outer solar system. The present series of experiments explores the effects of temperature, strain rate, grain size, and melt fraction on creep strength. In general, creep strength decreases with increasing temperature, decreasing strain rate, and increasing melt fraction. A transition from dislocation creep to diffusion creep occurs at finer grain sizes, higher temperatures, and lower strain rates.

  11. Pressure effects on collective density fluctuations in water and protein solutions

    PubMed Central

    Russo, Daniela; Laloni, Alessio; Filabozzi, Alessandra; Heyden, Matthias

    2017-01-01

    Neutron Brillouin scattering and molecular dynamics simulations have been used to investigate protein hydration water density fluctuations as a function of pressure. Our results show significant differences between the pressure and density dependence of collective dynamics in bulk water and in concentrated protein solutions. Pressure-induced changes in the tetrahedral order of the water HB network have direct consequences for the high-frequency sound velocity and damping coefficients, which we find to be a sensitive probe for changes in the HB network structure as well as the wetting of biomolecular surfaces. PMID:29073065

  12. Influence of metal ions intercalation on the vibrational dynamics of water confined between MXene layers

    DOE PAGES

    Osti, Naresh C.; Naguib, Michael; Ganeshan, Karthik; ...

    2017-11-21

    Two-dimensional carbides and nitrides of early transition metals (MXenes) combine high conductivity with hydrophilic surfaces, which make them promising for energy storage, electrocatalysis, and water desalination. Effects of intercalated metal ions on the vibrational states of water confined in Ti 3C 2T x MXenes have been explored using inelastic neutron scattering (INS) and molecular dynamics simulations to better understand the mechanisms that control MXenes’ behavior in aqueous electrolytes, water purification and other important applications. Here, we observe INS signal from water in all samples, pristine and with lithium, sodium or potassium ions intercalated between the 2D Ti 3C 2T xmore » layers. However, only a small amount of water is found to reside in Ti 3C 2T x intercalated with metal ions. Water in pristine Ti 3C 2T x is more disordered, with bulk-like characteristics, in contrast to intercalated Ti 3C 2T x, where water is more ordered, irrespective of the metal ions used for intercalation. The ordering of the confined water increases with the ion size. Lastly, this finding is further confirmed from molecular dynamics simulation which showed an increase in interference of water molecules with increasing ion size resulting in a concomitant decrease in water mobility, therefore, providing a guidance to tailor MXene properties for energy and environmental applications.« less

  13. Influence of metal ions intercalation on the vibrational dynamics of water confined between MXene layers

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

    Osti, Naresh C.; Naguib, Michael; Ganeshan, Karthik

    Two-dimensional carbides and nitrides of early transition metals (MXenes) combine high conductivity with hydrophilic surfaces, which make them promising for energy storage, electrocatalysis, and water desalination. Effects of intercalated metal ions on the vibrational states of water confined in Ti 3C 2T x MXenes have been explored using inelastic neutron scattering (INS) and molecular dynamics simulations to better understand the mechanisms that control MXenes’ behavior in aqueous electrolytes, water purification and other important applications. Here, we observe INS signal from water in all samples, pristine and with lithium, sodium or potassium ions intercalated between the 2D Ti 3C 2T xmore » layers. However, only a small amount of water is found to reside in Ti 3C 2T x intercalated with metal ions. Water in pristine Ti 3C 2T x is more disordered, with bulk-like characteristics, in contrast to intercalated Ti 3C 2T x, where water is more ordered, irrespective of the metal ions used for intercalation. The ordering of the confined water increases with the ion size. Lastly, this finding is further confirmed from molecular dynamics simulation which showed an increase in interference of water molecules with increasing ion size resulting in a concomitant decrease in water mobility, therefore, providing a guidance to tailor MXene properties for energy and environmental applications.« less

  14. Concrete-Water-Interaction and Ikaite (CaCO3.6H2O) Precipitation in a Man-Made River Bed

    NASA Astrophysics Data System (ADS)

    Boch, R.; Dietzel, M.; Reichl, P.; Leis, A.; Pölt, P.; Baldermann, A.

    2014-12-01

    Centimetre-thick, beige-colored and soft crusts were observed shortly after construction of a man-made river bed, i.e. a small natural river was bypassed flowing through a new bed lined with concrete and blocks. Hydrochemical investigations during wintertime - when water temperatures dropped down close to freezing - showed surprisingly high pH values up to 13.0 and elevated Ca2+ concentrations up to 200 mg/l. Both, the artifical and natural (downstream) section of the river bed were affected by the anomalous hydrochemistry and formation of prominent secondary precipitates. In order to better understand the particular and rapid water-rock-interaction, a hydrochemical monitoring program was launched and several of the delicate precipitates were recovered in refrigerator boxes in their original solution. The samples were analyzed in the laboratory within a few hours after sampling and stored at 1 °C. XRD and FT-IR patterns clearly revealed the predominant occurrence of "ikaite" in the crusts next to minor amounts of other carbonates (calcite, aragonite, vaterite) and detrital minerals. Ikaite - calcium carbonate hexahydrate - is a worldwide rarely documented carbonate mineral. This mineral is metastable and needs particular and narrow conditions in order to precipitate from solutions, i.e. a very limited water-temperature range between 0 and 4 °C (with ambient-pressure and low-salinity), highly alkaline pH conditions, high supersaturation values, and in many cases carbonate precipitation inhibitors (e.g. phosphates). Outside these conditions it disintegrates into calcite and water within minutes to hours. The few places of ikaite formation include Ikka Fjord in Greenland, Arctic- and Antarctic sea-ice and some sites of water mixing at Mono Lake, California. Combining detailed field monitoring results, solid-phase analyses and regional meteorological data (rainfall, water discharge, temperature) with hydrogeochemical modeling allows constraining the mechanisms of ikaite formation, as well as the temporal and spatial evolution of the waters and precipitates in the river bed.

  15. Heat flow and subsurface temperature as evidence for basin-scale ground-water flow, North Slope of Alaska

    USGS Publications Warehouse

    Deming, D.; Sass, J.H.; Lachenbruch, A.H.; De Rito, R. F.

    1992-01-01

    Several high-resolution temperature logs were made in each of 21 drillholes and a total of 601 thermal conductivity measurements were made on drill cuttings and cores. Near-surface heat flow (??20%) is inversely correlated with elevation and ranges from a low of 27 mW/m2 in the foothills of the Brooks Range in the south, to a high of 90 mW/m2 near the north coast. Subsurface temperatures and thermal gradients estimated from corrected BHTs are similarly much higher on the coastal plain than in the foothills province to the south. Significant east-west variation in heat flow and subsurface temperature is also observed; higher heat flow and temperature coincide with higher basement topography. The observed thermal pattern is consistent with forced convection by a topographically driven ground-water flow system. Average ground-water (Darcy) velocity in the postulated flow system is estimated to be of the order of 0.1 m/yr; the effective basin-scale permeability is estimated to be of the order of 10-14 m2. -from Authors

  16. Artificial neural network modeling of the water quality index using land use areas as predictors.

    PubMed

    Gazzaz, Nabeel M; Yusoff, Mohd Kamil; Ramli, Mohammad Firuz; Juahir, Hafizan; Aris, Ahmad Zaharin

    2015-02-01

    This paper describes the design of an artificial neural network (ANN) model to predict the water quality index (WQI) using land use areas as predictors. Ten-year records of land use statistics and water quality data for Kinta River (Malaysia) were employed in the modeling process. The most accurate WQI predictions were obtained with the network architecture 7-23-1; the back propagation training algorithm; and a learning rate of 0.02. The WQI forecasts of this model had significant (p < 0.01), positive, very high correlation (ρs = 0.882) with the measured WQI values. Sensitivity analysis revealed that the relative importance of the land use classes to WQI predictions followed the order: mining > rubber > forest > logging > urban areas > agriculture > oil palm. These findings show that the ANNs are highly reliable means of relating water quality to land use, thus integrating land use development with river water quality management.

  17. Water-based adhesives with tailored hydrophobic association: dilution resistance and improved setting behavior.

    PubMed

    Dundua, Alexander; Landfester, Katharina; Taden, Andreas

    2014-11-01

    Hydrophobic association and stimuli-responsiveness is a powerful tool towards water-based adhesives with strongly improved properties, which is demonstrated based on the example of hydrophobically modified alkali-soluble latexes (HASE) with modulated association. Their rheological properties are highly tunable due to the hydrophobic domains that act as physical crosslinking sites of adjustable interaction strength. Ethanol, propanol, and butanol are used as water-soluble model additives with different hydrophobicity in order to specifically target the association sites and impact the viscoelastic properties and stimuli-responsiveness. The rheological and mechanical property response upon dilution with water can be tailored, and dilution-resistant or even dilution-thickening systems are obtained. The investigations are of high importance for water-based adhesives, as our findings provide insight into general structure-property relationships to improve their setting behavior, especially upon contact with wet substrates. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Methods of eutrophication assessment in the context of the water framework directive: Examples from the Eastern Mediterranean coastal areas

    NASA Astrophysics Data System (ADS)

    Pavlidou, Alexandra; Simboura, Nomiki; Rousselaki, Eleni; Tsapakis, Manolis; Pagou, Kalliopi; Drakopoulou, Paraskevi; Assimakopoulou, Georgia; Kontoyiannis, Harilaos; Panayotidis, Panayotis

    2015-10-01

    A set of methodological tools were tested in order to assess the eutrophication quality of selected coastal areas in Eastern Mediterranean Sea, Greece, in the context of the Water Framework Directive under various anthropogenic pressures. Three, five-step tools, namely, TRIX, chlorophyll-a (chl-a) biomass classification scheme, and eutrophication index (E.I.) were applied in oligotrophic waters for (a) the whole water column and (b) the euphotic zone. The relationship among the eutrophication assessment indices and the ecological quality status (EcoQ) assessment indices for benthic macroinvertebrates (BENTIX index) and macroalgae (ecological evaluation index-EEIc) was also explored. Agricultural activities and mariculture are the pressures mostly related to the eutrophication assessment of the selected Greek coastal water bodies. Chl-a proved to be the criterion with the best overall correlation with the EcoQ indices, while TRIX with the lowest. Moreover, among the eutrophication indices, E.I. showed better overall agreement with BENTIX showing that probably it reflects the indirect relation of macroinvertebrates with water eutrophication in a better way. Among the eutrophication indices used, TRIX rather overestimated the eutrophication status of the selected coastal areas. The first stage of eutrophication was reflected more efficiently using E.I. than TRIX, but E.I. seems to be a rather sensitive index. A future modification of the high to good boundary of E.I. may be needed in order to demonstrate the high status of the relatively undisturbed Greek coastal sites.

  19. Tritium Separation from High Volume Dilute Aqueous Streams- Milestone Report for M3FT-15OR0302092

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

    Bhave, Ramesh R.; Jubin, Robert Thomas; Spencer, Barry B.

    2016-02-29

    This report describes the synthesis and evaluation of molecular sieve zeolite membranes to separate and concentrate tritiated water (HTO) from dilute HTO-bearing aqueous streams. Several silico alumino phosphate (SAPO-34) molecular sieve zeolite membranes were synthesized and characterized with gas and vapor permeation measurements. The pervaporation process performance was evaluated for the separation and concentration of tritiated water. Experiments were performed over a range of tritiated water concentration covering the range of concentration anticipated in nuclear fuel processing where potentially both acid and water streams are recycled. The permeate was recovered under vacuum. The tritium concentration ranged from 0.5 to 1more » mCi/mL which is about 0.1 mg/L or 0.1 ppm. The HTO concentration was three orders of magnitude lower than experiments performed with simulated feed containing HDO (>100 ppm) using deuterated water where high separation factors (>10) were obtained using SAPO membranes. Separation factor calculated from the measured tritium concentrations ranged from 0.83-0.98. Although the membrane performance characterization results were lower than expected, they can be explained on the basis of low feed volume and three orders of magnitude lower HTO concentration compared to HDO concentration in deuterated water. We have identified several new approaches, such as tuning the diffusion coefficient of HTO, that may help achieve preferential transport of tritium (HTO) resulting in a substantially more concentrated permeate.« less

  20. The Sterilization Effect of Cooperative Treatment of High Voltage Electrostatic Field and Variable Frequency Pulsed Electromagnetic Field on Heterotrophic Bacteria in Circulating Cooling Water

    NASA Astrophysics Data System (ADS)

    Gao, Xuetong; Liu, Zhian; Zhao, Judong

    2018-01-01

    Compared to other treatment of industrial circulating cooling water in the field of industrial water treatment, high-voltage electrostatic field and variable frequency pulsed electromagnetic field co-sterilization technology, an advanced technology, is widely used because of its special characteristics--low energy consumption, nonpoisonous and environmentally friendly. In order to get a better cooling water sterilization effect under the premise of not polluting the environment, some experiments about sterilization of heterotrophic bacteria in industrial circulating cooling water by cooperative treatment of high voltage electrostatic field and variable frequency pulsed electromagnetic field were carried out. The comparison experiment on the sterilization effect of high-voltage electrostatic field and variable frequency pulsed electromagnetic field co-sterilization on heterotrophic bacteria in industrial circulating cooling water was carried out by change electric field strength and pulse frequency. The results show that the bactericidal rate is selective to the frequency and output voltage, and the heterotrophic bacterium can only kill under the condition of sweep frequency range and output voltage. When the voltage of the high voltage power supply is 4000V, the pulse frequency is 1000Hz and the water temperature is 30°C, the sterilization rate is 48.7%, the sterilization rate is over 90%. Results of this study have important guiding significance for future application of magnetic field sterilization.

  1. On site experiments of the slanted soil treatment systems for domestic gray water.

    PubMed

    Itayama, Tomoaki; Kiji, Masato; Suetsugu, Aya; Tanaka, Nobuyuki; Saito, Takeshi; Iwami, Norio; Mizuochi, Motoyuki; Inamori, Yuhei

    2006-01-01

    In order to make a breakthrough for the acute problem of water shortage in the world, the key words "decentralization and re-use" are very important for new sustainable sanitation systems that will be developed. Therefore, we focused on a new treatments system called "a slanted soil treatment system" which combines a biotoilet system with a domestic grey water treatment system. Because this system is a low cost and compact system, the system can be easily introduced to homes in urban areas or in the suburbs of cities in many developing countries. In this study, we performed on site experiments carried out on Shikoku Island, Japan, for several years. We obtained the following results. The slanted soil treatment system could remove organic pollutants and total nitrogen and total phosphorus in grey water effectively. Furthermore, the system performance became high in the case of the high concentration of the influent water. The nitrification reaction and denitrification reaction were speculated to exist due to aerobic zones and anaerobic zones present in the slanted soil treatment system. The slanted soil treatment system could perform for approximately 3 years with zero maintenance. The plug flow model of 1st order reaction kinetics could describe the reaction in the slanted soil treatment system. However, it is necessary to improve the system to maintain the performance in all seasons.

  2. Meshless collocation methods for the numerical solution of elliptic boundary valued problems the rotational shallow water equations on the sphere

    NASA Astrophysics Data System (ADS)

    Blakely, Christopher D.

    This dissertation thesis has three main goals: (1) To explore the anatomy of meshless collocation approximation methods that have recently gained attention in the numerical analysis community; (2) Numerically demonstrate why the meshless collocation method should clearly become an attractive alternative to standard finite-element methods due to the simplicity of its implementation and its high-order convergence properties; (3) Propose a meshless collocation method for large scale computational geophysical fluid dynamics models. We provide numerical verification and validation of the meshless collocation scheme applied to the rotational shallow-water equations on the sphere and demonstrate computationally that the proposed model can compete with existing high performance methods for approximating the shallow-water equations such as the SEAM (spectral-element atmospheric model) developed at NCAR. A detailed analysis of the parallel implementation of the model, along with the introduction of parallel algorithmic routines for the high-performance simulation of the model will be given. We analyze the programming and computational aspects of the model using Fortran 90 and the message passing interface (mpi) library along with software and hardware specifications and performance tests. Details from many aspects of the implementation in regards to performance, optimization, and stabilization will be given. In order to verify the mathematical correctness of the algorithms presented and to validate the performance of the meshless collocation shallow-water model, we conclude the thesis with numerical experiments on some standardized test cases for the shallow-water equations on the sphere using the proposed method.

  3. Chemistry and potential mutagenicity of humic substances in waters from different watersheds in Britain and Ireland

    USGS Publications Warehouse

    Watt, B.E.; Malcolm, R.L.; Hayes, M.H.B.; Clark, N.W.E.; Chipman, J.K.

    1996-01-01

    Humic substances are amorphous organic macromolecules responsible for the hue of natural waters. They are also known to be precursors of mutagens formed on chlorination prior to distribution of drinking water. In this study humic substances from the waters of primary streams, from major rivers, and from reservoirs were isolated and fractionated into humic acids (HA), fulvic acids (FA) and XAD-4 acids using columns of XAD-8 and of XAD-4 resins in tandem, and the fractions from the different sources were chlorinated and assayed for mutagenicity. CPMAS 13C NMR spectroscopy showed marked differences in compositions not only between HA, FA, and XAD-4 acids from the same water samples, but also between the same fractions from water samples from different watersheds. There were found to be strong similarities between the fractions from watersheds which had closely related soil types. Aromaticity was greatest in HAs, and lowest in XAD-4 acids, and carboxyl contents and aliphatic character were greatest in the XAD-4 acids. Carbon content decreased in the order HA > FA > XAD-4 acids, and amino acids and neutral sugars contents decreased in the order HA > XAD-4 > FA. Titration data complemented aspects of the NMR data, demonstrating that carboxyl content decreased in the order XAD-4 acids > FA > HA, and indicated that phenolic character was highest in HAs and lowest in the XAD-4 acids. All samples tested gave rise to bacterial mutagens on chlorination. Although the mutagenicities were of the same order of magnitude for the chlorinated humic samples from the different sources, the samples which showed the greatest number of revertant bacterial colonies were from the Thames and Trent, large rivers with humic materials from diverse environments, and relatively high in amino acid contents.

  4. Competitive sorption affinity of sulfonamides and chloramphenicol antibiotics toward functionalized biochar for water and wastewater treatment.

    PubMed

    Ahmed, Mohammad Boshir; Zhou, John L; Ngo, Huu Hao; Guo, Wenshan; Johir, Md Abu Hasan; Belhaj, Dalel

    2017-08-01

    Competitive sorption of sulfamethazine (SMT), sulfamethoxazole (SMX), sulfathiazole (STZ) and chloramphenicol (CP) toward functionalized biochar (fBC) was highly pH dependent with maximum sorption at pH ∼4.0-4.25. Equilibrium data were well represented by the Langmuir and Freundlich models in the order STZ>SMX>CP>SMT. Kinetics data were slightly better fitted by the pseudo second-order model than pseudo first-order and intra-particle-diffusion models. Maximum sorptive interactions occurred at pH 4.0-4.25 through H-bonds formations for neutral sulfonamides species and through negative charge assisted H-bond (CAHB) formation for CP, in addition to π-π electron-donor-acceptor (EDA) interactions. EDA was the main mechanism for the sorption of positive sulfonamides species and CP at pH<2.0. Sorption of negative sulfonamides species and CP at pH>7.0 was regulated by H-bond formation and proton exchange with water by forming CAHB, respectively. The results suggested fBC to be highly efficient in removing antibiotics mixture. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Water quality deterioration at a karst spring (Gallusquelle, Germany) due to combined sewer overflow: evidence of bacterial and micro-pollutant contamination

    NASA Astrophysics Data System (ADS)

    Heinz, B.; Birk, S.; Liedl, R.; Geyer, T.; Straub, K. L.; Andresen, J.; Bester, K.; Kappler, A.

    2009-04-01

    The concurrent use of karst aquifers as drinking water resources and receptors of combined sewer overflow lacking appropriate pre-treatment may cause conflicts between drinking water supply and storm water management. A storm water tank (SWT) for combined wastewater is identified as the source of sporadic contamination of a karst spring (Gallusquelle, “Schwäbische Alb”, SW Germany) used for public water supply. Spring water quality was examined by routine and event sampling and by evaluating physicochemical and microbiological parameters. The total number of microbial colonies growing at 20°C and the number of Escherichia coli colonies rose to values up to four orders of magnitude higher than background, 2-5 days after overflow of the SWT. High concentrations of chloride, sodium, and total organic carbon (TOC) and high values of turbidity coincide with this increase. However, high bacterial contamination is also observed while turbidity and TOC are low. Several wastewater-related organic micro-pollutants such as chlorinated and non-chlorinated organophosphates were detected in the SWT and, depending on their K ow values and their biodegradability, in lower concentrations at the spring.

  6. Estimating the own-price elasticity of demand for irrigation water in the Musi catchment of India

    NASA Astrophysics Data System (ADS)

    Davidson, Brian; Hellegers, Petra

    2011-10-01

    SummaryAs irrigation water is an input into a production process, its demand must be 'derived'. According to theory, a derived demand schedule should be downward sloping and dependent on the outputs produced from it, the prices of other inputs and the price of the water itself. Problems arise when an attempt is made to estimate the demand for irrigation water and the resulting own-price elasticity of demand, as the uses to which water is put are spatially, temporarily and geographically diverse. Because water is not generally freely traded, what normally passes for an estimate of the own-price elasticity of demand for irrigation water is usually a well argued assumption or an estimate that is derived from a simulation model of a hypothesized producer. Such approaches tend to provide an inadequate explanation of what is an extremely complex and important relationship. An adequate explanation of the relationship between the price and the quantity demanded of water should be one that not only accords with the theoretical expectations, but also accounts for the diversity of products produced from water (which includes the management practices of farmers), the seasons in which it is used and over the region within which it is used. The objective in this article is to present a method of estimating the demand curve for irrigation water. The method uses actual field data which is collated using the Residual Method to determine the value of the marginal product of water deployed over a wide range of crops, seasons and regions. These values of the marginal products, all which must lie of the input demand schedule for water, are then ordered from the highest value to the lowest. Then, the amount of irrigation water used for each product, in each season and in each region is cumulatively summed over the range of uses according to the order of the values of the marginal products. This data, once ordered, is then used to econometrically estimate the demand schedule from which the own-price elasticity of demand for irrigation water can be derived. To illustrate the method, the values of the marginal product of water deployed in the Musi catchment in India are used to determine an own-price elasticity of demand for irrigation water which has some positive value to producers of approximately -0.64. For water that is most highly valued, the elasticity was found to be highly elastic at -2.12, while less valued water used in agriculture was far more inelastic at -0.44. Finally, for almost 36% of water deployed in the catchment the elasticity was logically determined to be perfectly elastic.

  7. The investigation of degradation reaction of various saccharides in high temperature and high pressure water

    NASA Astrophysics Data System (ADS)

    Saito, T.; Noguchi, S.; Matsumoto, T.; Sasaki, M.; Goto, M.

    2008-07-01

    Recently, conversions of polysaccharides included in biomass resources have been studied in order to recover valuable chemicals. Degradation of polysaccharides has been attracted by many researchers, whereas by-products from secondary reactions of the materials have not been studied very well. For the purpose of understanding reaction behavior of various monosaccharides in high-temperature and high-pressure water regions, we investigated reaction pathway and kinetics through reaction experiments of degradation of saccharides in subcritical water. The experiment was conducted by using continuous flow-type micro-reactors. Glucose was used as the starting material. From the experimental results, the conversion of glucose increased with increasing the residence time. The yields of fructose and 1, 6-anhydro-β-D-glucose decreased with increasing the residence time. The yields of organic acids and some aldehydes increased with increasing the residence time.

  8. Spatial distribution mapping of drinking water fluoride levels in Karnataka, India: fluoride-related health effects.

    PubMed

    Chowdhury, Chitta R; Shahnawaz, Khijmatgar; Kumari, Divya; Chowdhury, Avidyuti; Bedi, Raman; Lynch, Edward; Harding, Stewart; Grootveld, Martin

    2016-11-01

    (1) To estimate the concentrations of fluoride in drinking water throughout different zones and districts of the state of Karnataka. (2) To investigate the variation of fluoride concentration in drinking water from different sources, and its relationships to daily temperature and rainfall status in the regional districts. (3) To develop an updated fluoride concentration intensity map of the state of Karnataka, and to evaluate these data in the context of fluoride-related health effects such as fluorosis and their prevalence. Aqueous standard solutions of 10, 100 and 1,000 ppm fluoride (F - ) were prepared with analytical grade Na + /F - and a buffer; TISAB II was incorporated in both calibration standard and analysis solutions in order to remove the potentially interfering effects of trace metal ions. This analysis was performed using an ion-selective electrode (ISE), and mean determination readings for n = 5 samples collected at each Karnataka water source were recorded. The F - concentration in drinking water in Karnataka state was found to vary substantially, with the highest mean values recorded being in the north-eastern zone (1.61 ppm), and the lowest in the south-western one (only 0.41 ppm). Analysis of variance (ANOVA) demonstrated that there were very highly significant 'between-zone' and 'between-districts-within-zones' sources of variation (p < 10 -5 -10 -9 ), results consistent with a substantial spatial variance of water source F - levels within this state. The southern part of Karnataka has low levels of F - in its drinking water, and may require fluoridation treatment in order to mitigate for dental caries and further ailments related to fluoride deficiency. However, districts within the north-eastern region have contrastingly high levels of fluoride, an observation which has been linked to dental and skeletal fluorosis. This highlights a major requirement for interventional actions in order to ensure maintenance of the recommended range of fluoride concentrations (0.8-1.5 ppm) in Karnataka's drinking water sources. © Royal Society for Public Health 2016.

  9. Naphthenic acids removal from high TDS produced water by persulfate mediated iron oxide functionalized catalytic membrane, and by nanofiltration.

    PubMed

    Aher, Ashish; Papp, Joseph; Colburn, Andrew; Wan, Hongyi; Hatakeyama, Evan; Prakash, Prakhar; Weaver, Ben; Bhattacharyya, Dibakar

    2017-11-01

    Oil industries generate large amounts of produced water containing organic contaminants, such as naphthenic acids (NA) and very high concentrations of inorganic salts. Recovery of potable water from produced water can be highly energy intensive is some cases due to its high salt concentration, and safe discharge is more suitable. Here, we explored catalytic properties of iron oxide (Fe x O y nanoparticles) functionalized membranes in oxidizing NA from water containing high concentrations of total dissolved solids (TDS) using persulfate as an oxidizing agent. Catalytic decomposition of persulfate by Fe x O y functionalized membranes followed pseudo-first order kinetics with an apparent activation energy of 18 Kcal/mol. Fe x O y functionalized membranes were capable of lowering the NA concentrations to less than discharge limits of 10 ppm at 40 °C. Oxidation state of iron during reaction was quantified. Membrane performance was investigated for extended period of time. A coupled process of advanced oxidation catalyzed by membrane and nanofiltration was also evaluated. Commercially available nanofiltration membranes were found capable of retaining NA from water containing high concentrations of dissolved salts. Commercial NF membranes, Dow NF270 (Dow), and NF8 (Nanostone) had NA rejection of 79% and 82%, respectively. Retentate for the nanofiltration was further treated with advanced oxidation catalyzed by Fe x O y functionalized membrane for removal of NA.

  10. Acoustic radiation force on an air bubble and soft fluid spheres in ideal liquids: example of a high-order Bessel beam of quasi-standing waves.

    PubMed

    Mitri, F G

    2009-04-01

    The partial wave series for the scattering of a high-order Bessel beam (HOBB) of acoustic quasi-standing waves by an air bubble and fluid spheres immersed in water and centered on the axis of the beam is applied to the calculation of the acoustic radiation force. A HOBB refers to a type of beam having an axial amplitude null and an azimuthal phase gradient. Radiation force examples obtained through numerical evaluation of the radiation force function are computed for an air bubble, a hexane, a red blood and mercury fluid spheres in water. The examples were selected to illustrate conditions having progressive, standing and quasi-standing waves with appropriate selection of the waves' amplitude ratio. An especially noteworthy result is the lack of a specific vibrational mode contribution to the radiation force determined by appropriate selection of the HOBB parameters.

  11. A comprehensive insight into bacterial virulence in drinking water using 454 pyrosequencing and Illumina high-throughput sequencing.

    PubMed

    Huang, Kailong; Zhang, Xu-Xiang; Shi, Peng; Wu, Bing; Ren, Hongqiang

    2014-11-01

    In order to comprehensively investigate bacterial virulence in drinking water, 454 pyrosequencing and Illumina high-throughput sequencing were used to detect potential pathogenic bacteria and virulence factors (VFs) in a full-scale drinking water treatment and distribution system. 16S rRNA gene pyrosequencing revealed high bacterial diversity in the drinking water (441-586 operational taxonomic units). Bacterial diversity decreased after chlorine disinfection, but increased after pipeline distribution. α-Proteobacteria was the most dominant taxonomic class. Alignment against the established pathogen database showed that several types of putative pathogens were present in the drinking water and Pseudomonas aeruginosa had the highest abundance (over 11‰ of total sequencing reads). Many pathogens disappeared after chlorine disinfection, but P. aeruginosa and Leptospira interrogans were still detected in the tap water. High-throughput sequencing revealed prevalence of various pathogenicity islands and virulence proteins in the drinking water, and translocases, transposons, Clp proteases and flagellar motor switch proteins were the predominant VFs. Both diversity and abundance of the detectable VFs increased after the chlorination, and decreased after the pipeline distribution. This study indicates that joint use of 454 pyrosequencing and Illumina sequencing can comprehensively characterize environmental pathogenesis, and several types of putative pathogens and various VFs are prevalent in drinking water. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. Bacteria in atmospheric waters: Detection, characteristics and implications

    NASA Astrophysics Data System (ADS)

    Hu, Wei; Niu, Hongya; Murata, Kotaro; Wu, Zhijun; Hu, Min; Kojima, Tomoko; Zhang, Daizhou

    2018-04-01

    In this review paper, we synthesize the current knowledges about bacteria in atmospheric waters, e.g., cloud, fog, rain, and snow, most of which were obtained very recently. First, we briefly describe the importance of bacteria in atmospheric waters, i.e., the essentiality of studying bacteria in atmospheric waters in understanding aerosol-cloud-precipitation-climate interactions in the Earth system. Next, approaches to collect atmospheric water samples for the detection of bacteria and methods to identify the bacteria are summarized and compared. Then the available data on the abundance, viability and community composition of bacteria in atmospheric waters are summarized. The average bacterial concentration in cloud water was usually on the order 104-105 cells mL-1, while that in precipitation on the order 103-104 cells mL-1. Most of the bacteria were viable or metabolically active. Their community composition was highly diverse and differed at various sites. Factors potentially influencing the bacteria, e.g., air pollution levels and sources, meteorological conditions, seasonal effect, and physicochemical properties of atmospheric waters, are described. After that, the implications of bacteria present in atmospheric waters, including their effect on nucleation in clouds, atmospheric chemistry, ecosystems and public health, are briefly discussed. Finally, based on the current knowledges on bacteria in atmospheric waters, which in fact remains largely unknown, we give perspectives that should be paid attention to in future studies.

  13. Forecasting the Water Demand in Chongqing, China Using a Grey Prediction Model and Recommendations for the Sustainable Development of Urban Water Consumption

    PubMed Central

    Wu, Hua’an; Zhou, Meng

    2017-01-01

    High accuracy in water demand predictions is an important basis for the rational allocation of city water resources and forms the basis for sustainable urban development. The shortage of water resources in Chongqing, the youngest central municipality in Southwest China, has significantly increased with the population growth and rapid economic development. In this paper, a new grey water-forecasting model (GWFM) was built based on the data characteristics of water consumption. The parameter estimation and error checking methods of the GWFM model were investigated. Then, the GWFM model was employed to simulate the water demands of Chongqing from 2009 to 2015 and forecast it in 2016. The simulation and prediction errors of the GWFM model was checked, and the results show the GWFM model exhibits better simulation and prediction precisions than those of the classical Grey Model with one variable and single order equation GM(1,1) for short and the frequently-used Discrete Grey Model with one variable and single order equation, DGM(1,1) for short. Finally, the water demand in Chongqing from 2017 to 2022 was forecasted, and some corresponding control measures and recommendations were provided based on the prediction results to ensure a viable water supply and promote the sustainable development of the Chongqing economy. PMID:29140266

  14. Water-Rich Fluid Material Containing Orderly Condensed Proteins.

    PubMed

    Nojima, Tatsuya; Iyoda, Tomokazu

    2017-01-24

    A fluid material with high protein content (120-310 mg mL -1 ) was formed through the ordered self-assembly of native proteins segregated from water. This material is instantly prepared by the simple mixing of a protein solution with anionic and cationic surfactants. By changing the ratio of the surfactants based on the electrostatic characteristics of the target protein, we observed that the surfactants could function as a versatile molecular glue for protein assembly. Moreover, these protein assemblies could be disassembled back into an aqueous solution depending on the salt conditions. Owing to the water-retaining properties of the hydrophilic part of surfactants, the proteins in this material are in a water-rich environment, which maintains their native structure and function. The inclusion of water also provides functional extensibility to this material, as demonstrated by the preparation of an enzymatically active gel. We anticipate that the unique features of this material will permit the use of proteins not only in solution but also as elements of integrated functionalized materials. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Occurrence and Comparative Toxicity of Haloacetaldehyde Disinfection Byproducts in Drinking Water.

    PubMed

    Jeong, Clara H; Postigo, Cristina; Richardson, Susan D; Simmons, Jane Ellen; Kimura, Susana Y; Mariñas, Benito J; Barcelo, Damia; Liang, Pei; Wagner, Elizabeth D; Plewa, Michael J

    2015-12-01

    The introduction of drinking water disinfection greatly reduced waterborne diseases. However, the reaction between disinfectants and natural organic matter in the source water leads to an unintended consequence, the formation of drinking water disinfection byproducts (DBPs). The haloacetaldehydes (HALs) are the third largest group by weight of identified DBPs in drinking water. The primary objective of this study was to analyze the occurrence and comparative toxicity of the emerging HAL DBPs. A new HAL DBP, iodoacetaldehyde (IAL) was identified. This study provided the first systematic, quantitative comparison of HAL toxicity in Chinese hamster ovary cells. The rank order of HAL cytotoxicity is tribromoacetaldehyde (TBAL) ≈ chloroacetaldehyde (CAL) > dibromoacetaldehyde (DBAL) ≈ bromochloroacetaldehyde (BCAL) ≈ dibromochloroacetaldehyde (DBCAL) > IAL > bromoacetaldehyde (BAL) ≈ bromodichloroacetaldehyde (BDCAL) > dichloroacetaldehyde (DCAL) > trichloroacetaldehyde (TCAL). The HALs were highly cytotoxic compared to other DBP chemical classes. The rank order of HAL genotoxicity is DBAL > CAL ≈ DBCAL > TBAL ≈ BAL > BDCAL>BCAL ≈ DCAL>IAL. TCAL was not genotoxic. Because of their toxicity and abundance, further research is needed to investigate their mode of action to protect the public health and the environment.

  16. Water injection into vapor- and liquid-dominated reservoirs: Modeling of heat transfer and mass transport

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

    Pruess, K.; Oldenburg, C.; Moridis, G.

    1997-12-31

    This paper summarizes recent advances in methods for simulating water and tracer injection, and presents illustrative applications to liquid- and vapor-dominated geothermal reservoirs. High-resolution simulations of water injection into heterogeneous, vertical fractures in superheated vapor zones were performed. Injected water was found to move in dendritic patterns, and to experience stronger lateral flow effects than predicted from homogeneous medium models. Higher-order differencing methods were applied to modeling water and tracer injection into liquid-dominated systems. Conventional upstream weighting techniques were shown to be adequate for predicting the migration of thermal fronts, while higher-order methods give far better accuracy for tracer transport.more » A new fluid property module for the TOUGH2 simulator is described which allows a more accurate description of geofluids, and includes mineral dissolution and precipitation effects with associated porosity and permeability change. Comparisons between numerical simulation predictions and data for laboratory and field injection experiments are summarized. Enhanced simulation capabilities include a new linear solver package for TOUGH2, and inverse modeling techniques for automatic history matching and optimization.« less

  17. Interplay of the Glass Transition and the Liquid-Liquid Phase Transition in Water

    PubMed Central

    Giovambattista, Nicolas; Loerting, Thomas; Lukanov, Boris R.; Starr, Francis W.

    2012-01-01

    Water has multiple glassy states, often called amorphous ices. Low-density (LDA) and high-density (HDA) amorphous ice are separated by a dramatic, first-order like phase transition. It has been argued that the LDA-HDA transformation connects to a first-order liquid-liquid phase transition (LLPT) above the glass transition temperature Tg. Direct experimental evidence of the LLPT is challenging to obtain, since the LLPT occurs at conditions where water rapidly crystallizes. In this work, we explore the implications of a LLPT on the pressure dependence of Tg(P) for LDA and HDA by performing computer simulations of two water models – one with a LLPT, and one without. In the absence of a LLPT, Tg(P) for all glasses nearly coincide. When there is a LLPT, different glasses exhibit dramatically different Tg(P) which are directly linked with the LLPT. Available experimental data for Tg(P) are only consistent with the scenario including a LLPT. PMID:22550566

  18. Interplay of the Glass Transition and the Liquid-Liquid Phase Transition in Water

    NASA Astrophysics Data System (ADS)

    Giovambattista, Nicolas; Loerting, Thomas; Lukanov, Boris R.; Starr, Francis W.

    2012-05-01

    Water has multiple glassy states, often called amorphous ices. Low-density (LDA) and high-density (HDA) amorphous ice are separated by a dramatic, first-order like phase transition. It has been argued that the LDA-HDA transformation connects to a first-order liquid-liquid phase transition (LLPT) above the glass transition temperature Tg. Direct experimental evidence of the LLPT is challenging to obtain, since the LLPT occurs at conditions where water rapidly crystallizes. In this work, we explore the implications of a LLPT on the pressure dependence of Tg(P) for LDA and HDA by performing computer simulations of two water models - one with a LLPT, and one without. In the absence of a LLPT, Tg(P) for all glasses nearly coincide. When there is a LLPT, different glasses exhibit dramatically different Tg(P) which are directly linked with the LLPT. Available experimental data for Tg(P) are only consistent with the scenario including a LLPT.

  19. Experimental evidence of a liquid-liquid transition in interfacial water

    NASA Astrophysics Data System (ADS)

    Zanotti, J.-M.; Bellissent-Funel, M.-C.; Chen, S.-H.

    2005-07-01

    At ambient pressure, bulk liquid water shows an anomalous increase of thermodynamic quantities and apparent divergences of dynamic properties on approaching a temperature Ts of 228 K. At normal pressure, supercooled water spontaneously freezes below the homogeneous nucleation temperature, TH = 235 K. Upon heating, the two forms of Amorphous Solid Water (ASW), LDA (Low Density Amorphous Ice) and HDA (High Density Amorphous Ice), crystallise above TX = 150 K. As a consequence, up to now no experiment has been able to explore the properties of liquid water in this very interesting temperature range between 150 and 235 K. We present nanosecond-time-scale measurements of local rotational and translational dynamics of interfacial, non-crystalline, water from 77 to 280 K. These experimental dynamic results are combined with calorimetric and diffraction data to show that after exhibiting a glass transition at 165 K, interfacial water experiences a first-order liquid-liquid transition at 240 K from a low-density to a high-density liquid. This is the first direct evidence of the existence of a liquid-liquid transition involving water.

  20. Temperature-Responsive Polymers for Biological Applications

    DTIC Science & Technology

    2003-06-01

    polymer temperature response in water by varying chemical composition of the monomer. In order to achieve this a series of polymers were designed and...varying the m/n composition and polymer type. Polymer grafting onto the silicon surface exhibits similar solubility behaviour. Adhesion energy...Driven by the high promise for biomedical applications, polymers that exhibit a response in water at about 37ºC are of particular interest. Taylor and

  1. Cl/B ratio of geothermal fluid around Slamet Volcano, Jawa Tengah, Indonesia

    NASA Astrophysics Data System (ADS)

    Harijoko, Agung; Juhri, Saefudin

    2017-12-01

    Geothermal manifestations occurred in four areas surrounding Slamet Volcano, such as Guci, Baturraden, Paguyangan, and Bantarkawung. These areas are located of about 7.5 km, 8 km, 25 km and 33 km from the summit of Slamet volcano, respectively. We analyzed the chemical composition of cold and hot hater in order to understand the genesis and hydrological the relationship of the hot springs. The plot on HCO3-Cl-SO4 ternary diagram classified the hot water into four water types i.e. chloride-bicarbonate water (Bantarkawung), chloride water (Paguyangan), sulfate-chloride water (Baturraden), and bicarbonate water (Guci). The Cl/B ratio values indicate that the southern part of the Slamet volcano (Baturaden) hot springs have high Cl/B ratio compared to that of the northern hot springs (Guci area). While the hot springs in the western part (Paguyangan and Bantarkawung) are classified into high and low Cl/B ratio. This indicates that the hot springs in Paguyangan and Bantarkawung are the outflow of Baturraden and Guci.

  2. Fracture toughness of Alloy 690 and EN52 weld in air and water

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

    Brown, C.M.; Mills, W.J.

    1999-06-01

    The effect of low and high temperature water with high hydrogen on the fracture toughness of Alloy 690 and its weld, EN52, was characterized using elastic-plastic J{sub IC} methodology. While both materials display excellent fracture resistance in air and elevated temperature (>93 C) water, a dramatic degradation in toughness is observed in 54 C water. The loss of toughness is associated with a hydrogen-induced intergranular cracking mechanism where hydrogen is picked up from the water. Comparison of the cracking behavior in low temperature water with that for hydrogen-precharged specimens tested in air indicates that the critical local hydrogen content requiredmore » to cause low temperature embrittlement is on the order of 120 to 160 ppm. Loading rate studies show that the cracking resistance is significantly improved at rates above ca. 1000 MPa{radical}m/h because there is insufficient time to produce grain boundary embrittlement. Electron fractographic examinations were performed to correlate cracking behavior with microstructural features and operative fracture mechanics.« less

  3. Fracture toughness of alloy 690 and EN52 welds in air and water

    NASA Astrophysics Data System (ADS)

    Brown, C. M.; Mills, W. J.

    2002-06-01

    The effect of low- and high-temperature water with high hydrogen on the fracture toughness of alloy 690 and its weld, EN52, was characterized using elastic-plastic J IC methodology. While both materials display excellent fracture resistance in air and elevated-temperature (>93 °C) water, a dramatic degradation in toughness is observed in 54 °C water. The loss of toughness is associated with a hydrogen-induced intergranular cracking mechanism, where hydrogen is picked up from the water. Comparison of the cracking behavior in low-temperature water with that for hydrogen-precharged specimens tested in air indicates that the critical local hydrogen content required to cause low-temperature embrittlement is on the order of 120 to 160 ppm. Loading-rate studies show that cracking resistance is improved at rates above ˜ 1000 MPa √m/h, because there is insufficient time to produce grain-boundary embrittlement. Electron fractographic examinations were performed to correlate cracking behavior with microstructural features and operative fracture mechanisms.

  4. Direct exfoliation and dispersion of two-dimensional materials in pure water via temperature control.

    PubMed

    Kim, Jinseon; Kwon, Sanghyuk; Cho, Dae-Hyun; Kang, Byunggil; Kwon, Hyukjoon; Kim, Youngchan; Park, Sung O; Jung, Gwan Yeong; Shin, Eunhye; Kim, Wan-Gu; Lee, Hyungdong; Ryu, Gyeong Hee; Choi, Minseok; Kim, Tae Hyeong; Oh, Junghoon; Park, Sungjin; Kwak, Sang Kyu; Yoon, Suk Wang; Byun, Doyoung; Lee, Zonghoon; Lee, Changgu

    2015-09-15

    The high-volume synthesis of two-dimensional (2D) materials in the form of platelets is desirable for various applications. While water is considered an ideal dispersion medium, due to its abundance and low cost, the hydrophobicity of platelet surfaces has prohibited its widespread use. Here we exfoliate 2D materials directly in pure water without using any chemicals or surfactants. In order to exfoliate and disperse the materials in water, we elevate the temperature of the sonication bath, and introduce energy via the dissipation of sonic waves. Storage stability greater than one month is achieved through the maintenance of high temperatures, and through atomic and molecular level simulations, we further discover that good solubility in water is maintained due to the presence of platelet surface charges as a result of edge functionalization or intrinsic polarity. Finally, we demonstrate inkjet printing on hard and flexible substrates as a potential application of water-dispersed 2D materials.

  5. Dehydration of multilamellar fatty acid membranes: Towards a computational model of the stratum corneum

    NASA Astrophysics Data System (ADS)

    MacDermaid, Christopher M.; DeVane, Russell H.; Klein, Michael L.; Fiorin, Giacomo

    2014-12-01

    The level of hydration controls the cohesion between apposed lamellae of saturated free fatty acids found in the lipid matrix of stratum corneum, the outermost layer of mammalian skin. This multilamellar lipid matrix is highly impermeable to water and ions, so that the local hydration shell of its fatty acids may not always be in equilibrium with the acidity and relative humidity, which significantly change over a course of days during skin growth. The homeostasis of the stratum corneum at each moment of its growth likely requires a balance between two factors, which affect in opposite ways the diffusion of hydrophilic species through the stratum corneum: (i) an increase in water order as the lipid lamellae come in closer contact, and (ii) a decrease in water order as the fraction of charged fatty acids is lowered by pH. Herein molecular dynamics simulations are employed to estimate the impact of both effects on water molecules confined between lamellae of fatty acids. Under conditions where membrane undulations are energetically favorable, the charged fatty acids are able to sequester cations around points of contact between lamellae that are fully dehydrated, while essentially maintaining a multilamellar structure for the entire system. This observation suggests that the undulations of the fatty acid lamellae control the diffusion of hydrophilic species through the water phase by altering the positional and rotational order of water molecules in the embedded/occluded "droplets."

  6. Estimated Quantity of Water in Fractured Bedrock Units on Mt. Desert Island, and Estimated Ground-Water Use, Recharge, and Dilution of Nitrogen in Septic Waste in the Bar Harbor Area, Maine

    USGS Publications Warehouse

    Nielsen, Martha G.

    2002-01-01

    In 2002, the U.S. Geological Survey, in cooperation with the town of Bar Harbor, Maine, and the National Park Service, conducted a study to assess the quantity of water in the bedrock units underlying Mt. Desert Island, and to estimate water use, recharge, and dilution of nutrients from domestic septic systems overlying the bedrock units in several watersheds in rural Bar Harbor. Water quantity was calculated as the static volume of water in the top 600 feet of saturated thickness of the bedrock units. Volumes of water were estimated on the basis of effective fracture porosities for the five different rock types found on Mt. Desert Island. Values of porosities for the various bedrock units from the literature range more than five orders of magnitude, although the possible range in porosities for most individual rock types is on the order of three orders of magnitude. The static volume of water in the various units may range from a low of 4,000 gallons per acre for intrusive igneous rocks (primarily granites) to 20 million gallons per acre for the Cranberry Island Volcanics, but given the range in porosity estimates, these numbers can vary by orders of magnitude. Water-use data for the municipal water supply in the Town of Bar Harbor (1998-2000) indicate that residential usage averages 225 gallons per household per day. Recharge to the bedrock units in rural Bar Harbor was bracketed using low, medium, and high estimates, which were 3, 9, and 14 inches per year, respectively. Water use in 2001 was about 2.5 percent of the total estimated medium recharge (9 inches per year) in the study area. Dilution of nitrogen in septic effluent discharging to the bedrock aquifer was evaluated for the development density in 2001. On the basis of an assumed concentration of 47 mg/L of nitrogen in septic system discharge, dilution factors in populated rural Bar Harbor watersheds ranged from 4 to 151, for the housing density in 2001. Understanding that ground water in this fractured bedrock system mixes slowly, the fully mixed average nitrate-nitrogen concentrations in ground water estimated for the watersheds ranged from 0.1 to 11 mg/L.

  7. Nano-confined water in the interlayers of hydrocalumite: Reorientational dynamics probed by neutron spectroscopy and molecular dynamics computer simulations

    NASA Astrophysics Data System (ADS)

    Kalinichev, A. G.; Faraone, A.; Udovic, T.; Kolesnikov, A. I.; de Souza, N. R.; Reinholdt, M. X.; Kirkpatrick, R.

    2008-12-01

    Layered double hydroxides (LDHs, anionic clays) represent excellent model systems for detailed molecular- level studies of the structure, dynamics, and energetics of nano-confined water in mineral interlayers and nano-pores, because LDH interlayers can have a well-defined structures and contain H2O molecules and a wide variety of anions in structurally well-defined positions and coordinations. [Ca2Al(OH)6]Cl·2H2O, also known as hydrocalumite or Friedel's salt, has a well- ordered Ca,Al distribution in the hydroxide layer and a very high degree of H2O,Cl ordering in the interlayer. It is also one of the only LDH phase for which a single crystal structure refinement is available. Thus, it is currently the best model compound for understanding the structure and dynamical behavior of interlayer and surface species in other, less-ordered, LDHs. We investigated the structural and dynamic behavior of water in the interlayers of hydrocalumite using inelastic (INS) and quasielastic (QENS) neutron scattering and molecular dynamics computer simulations. The comperehensive neutron scattering studies were performed for one fully hydrated and one dehydrated sample of hydrocalumite using several complementary instruments (HFBS, DCS and FANS at NCNR; HRMECS and QENS at IPNS) at temperatures above and below the previously discovered order-disorder interlayer phase transition. Together the experimental and molecular modeling results capture the important details of the dynamics of nano-confined water and the effects of the orientational ordering of H2O molecules above and below the phase transition. They provide otherwise unobtainable experimental information about the transformation of H2O librational and diffusional modes across the order-disorder phase transition and significantly add to our current understanding of the structure and dynamics of water in LDH phases based on the earlier NMR, IR, X-ray, and calorimetric measurements. The approach can now be extended to probe the dynamics of nano-confined and interfacial water in more disordered phases (LDH, clays, cement, etc.), for which much less initial structural information is available.

  8. A framework and a set of tools called Nutting models to estimate retention capacities and loads of nitrogen and phosphorus in rivers at catchment and national level (France)

    NASA Astrophysics Data System (ADS)

    Legeay, Pierre-Louis; Moatar, Florentina; Dupas, Rémi; Gascuel-Odoux, Chantal

    2016-04-01

    The Nutting-N and Nutting-P models (Dupas et al., 2013, 2015) have been developed to estimate Nitrogen and Phosphorus nonpoint-source emissions to surface water, using readily available data. These models were inspired from US model SPARROW (Smith al., 1997) and European model GREEN (Grizzetti et al., 2008), i.e. statistical approaches consisting of linking nitrogen and phosphorus surplus to catchment's land and rivers characteristics to find the catchment relative retention capacities. The nutrient load (L) at the outlet of each catchment is expressed as: L=R*(B*DS+PS) [1] where DS is diffuse sources (i.e. surplus in kg.ha-1/yr-1 for N, P storage in soil for P), PS is point sources from domestic and industrial origin (kg.ha-1.yr-1), R and B are the river system and basin reduction factor, respectively and they combine observed variables and calibrated parameters. The model was calibrated on independent catchments for the 2005-2009 and 2008-2012 periods. Variables were selected according to Bayesian Information Criterion (BIC) in order to optimize the predictive performance of the models. From these basic models, different improvements have been realized to build a framework and a set of tools: 1) a routing module has been added in order to improve estimations on 4 or 5 stream order, i.e. upscaling the basic Nutting approach; 2) a territorial module, in order to test the models at local scale (from 500 to 5000 km²); 3) a seasonal estimation has been investigated. The basic approach as well territorial application will be illustrated. These tools allow water manager to identify areas at risk where high nutrients loads are estimated, as well areas where retention is potentially high and can buffer high nutrient sources. References Dupas R., Curie F., Gascuel-Odoux C., Moatar F., Delmas M., Parnaudeau, V., Durand P., 2013. Assessing N emissions in surface water at the national level: Comparison of country-wide vs. regionalized models. Science of the Total Environment 443, 152-162 Dupas R., Delmas M., Dorioz J.M., Garnier J., Moatar F., Gascuel-Odoux C., 2015. Assessing the impact of agricultural pressures on N and P loads andeutrophication risk. Ecological Indicators 48, 396-407. Grizzetti B., Bouraoui F., De Marsily G., 2008. Assessing nitrogen pressures on European surface water. Global Biogeochemical Cycles; 22. Smith R.A., Schwarz G.E., Alexander R.B., 1997. Regional interpretation of water-quality monitoring data. Water Resources Research 1997; 33: 2781-2798.

  9. Transport studies in polymer electrolyte fuel cell with porous metallic flow field at ultra high current density

    NASA Astrophysics Data System (ADS)

    Srouji, Abdul-Kader

    Achieving cost reduction for polymer electrolyte fuel cells (PEFC) requires a simultaneous effort in increasing power density while reducing precious metal loading. In PEFCs, the cathode performance is often limiting due to both the slow oxygen reduction reaction (ORR), and mass transport limitation caused by limited oxygen diffusion and liquid water flooding at high current density. This study is motivated by the achievement of ultra-high current density through the elimination of the channel/land (C/L) paradigm in PEFC flow field design. An open metallic element (OME) flow field capable of operating at unprecedented ultra-high current density (3 A/cm2) introduces new advantages and limitations for PEFC operation. The first part of this study compares the OME with a conventional C/L flow field, through performance and electrochemical diagnostic tools such as electrochemical impedance spectroscopy (EIS). The results indicate the uniqueness of the OME's mass transport improvement. No sign of operation limitation due to flooding is noted. The second part specifically examines water management at high current density using the OME flow field. A unique experimental setup is developed to measure steady-state and transient net water drag across the membrane, in order to characterize the fundamental aspects of water transport at high current density with the OME. Instead of flooding, the new limitation is identified to be anode side dry-out of the membrane, caused by electroosmotic drag. The OME improves water removal from the cathode, which immediately improves oxygen transport and performance. However, the low water content in the cathode reduces back diffusion of water to the membrane, and electroosmotic drag dominates at high current density, leading to dry-out. The third part employs the OME flow field as a tool that avoids C/L effects endemic to a typical flow field, in order to study oxygen transport resistance at the catalyst layer of a PEFC. In open literature, a resistance of unknown origin, was shown to directly or indirectly scale with Pt loading. A lack of understanding of the mechanism responsible for such resistance is noted, and several possible theories have been proposed. This lack of fundamental understanding of the origins of this resistance adds complexity to computational models which are designed to capture performance behavior with ultra-low loading electrodes. By employing the OME flow field as a tool to study this phenomena, the origins of the transport resistance appearing at ultra-low Platinum (Pt) loading is proposed to be an increase in oxygen dilution resistance through water film.

  10. Interplay of the Glass Transition and the Liquid-Liquid Phase Transition in Water

    NASA Astrophysics Data System (ADS)

    Giovambattista, Nicolas

    2013-03-01

    Most liquids can form a single glass or amorphous state when cooled sufficiently fast (in order to prevent crystallization). However, there are a few substances that are relevant to scientific and technological applications which can exist in at least two different amorphous states, a property known as polyamorphism. Examples include silicon, silica, and in particular, water. In the case of water, experiments show the existence of a low-density (LDA) and high-density (HDA) amorphous ice that are separated by a dramatic, first-order like phase transition. It has been argued that the LDA-HDA transformation evolves into a first-order liquid-liquid phase transition (LLPT) at temperatures above the glass transition temperature Tg. However, obtaining direct experimental evidence of the LLPT has been challenging since the LLPT occurs at conditions where water rapidly crystallizes. In this talk, I will (i) discuss the general phenomenology of polyamorphism in water and its implications, and (ii) explore the effects of a LLPT on the pressure dependence of Tg(P) for LDA and HDA. Our study is based on computer simulations of two water models - one with a LLPT (ST2 model), and one without (SPC/E model). In the absence of a LLPT, Tg(P) for all glasses nearly coincide. Instead, when there is a LLPT, different glasses exhibit dramatically different Tg(P) loci which are directly linked with the LLPT. Available experimental data for Tg(P) are only consistent with the scenario that includes a LLPT (ST2 model) and hence, our results support the view that a LLPT may exist for the case of water.

  11. On the contribution of vibrational anharmonicity to the binding energies of water clusters.

    PubMed

    Diri, Kadir; Myshakin, Evgeniy M; Jordan, Kenneth D

    2005-05-05

    The second-order vibrational perturbation theory method has been used together with the B3LYP and MP2 electronic structure methods to investigate the effects of anharmonicity on the vibrational zero-point energy (ZPE) contributions to the binding energies of (H2O)n, n = 2-6, clusters. For the low-lying isomers of (H2O)6, the anharmonicity correction to the binding energy is calculated to range from -248 to -355 cm(-1). It is also demonstrated that although high-order electron correlation effects are important for the individual vibrational frequencies, they are relatively unimportant for the net ZPE contributions to the binding energies of water clusters.

  12. Development of an Integrated Modeling Framework for Simulations of Coastal Processes in Deltaic Environments Using High-Performance Computing

    DTIC Science & Technology

    2008-01-01

    exceeds the local water depth. The approximation eliminates the vertical dimension of the elliptic equation that is normally required for the fully non...used for vertical resolution. The shallow water equations (SWE) are a set of non-linear hyperbolic equations. As the equations are derived under...linear standing wave with a wavelength of 10 m in a square 10 m by 10 m basin. The still water depth is 0.5 m. In order to compare with the analytical

  13. Distribution and bioaccumulation of endocrine disrupting chemicals in water, sediment and fishes in a shallow Chinese freshwater lake: Implications for ecological and human health risks.

    PubMed

    Dan Liu; Wu, Shengmin; Xu, Huaizhou; Zhang, Qin; Zhang, Shenghu; Shi, Lili; Yao, Cheng; Liu, Yanhua; Cheng, Jie

    2017-06-01

    The occurrence, distribution and bioaccumulation of six endocrine disrupting compounds (EDCs) were investigated in water, sediment and biota samples from Luoma Lake, a shallow Chinese freshwater lake. Total concentrations of ∑phenolic EDCs were much higher than ∑estrogens EDCs in both waters and sediments. There were not obvious differences on the concentrations of target compounds [except nonylphenol (NP)] in upstream, lake and downstream locations, these may be suggested that they were mainly affected by non-point discharges in this area. However, the high concentration of NP in water may be associated with the discharge of rural domestic wastewater without thorough treatment. Furthermore, concentrations of NP were about 2-3 order magnitude higher than those of OP in both water and sediment compartments. Relatively higher bioaccumulation factors (BAF) were obtained for DES and EE2. Ecological risk assessment revealed greater risk of NP in surface water, which may pose a serious threat to aquatic ecosystems. The estrogen equivalent concentration (EEQ) of male were higher than those in female, and occurred in the order of city >rural-urban>countryside. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Micropollutants in source separated wastewater streams and recovered resources of source separated sanitation.

    PubMed

    Butkovskyi, A; Leal, L Hernandez; Zeeman, G; Rijnaarts, H H M

    2017-07-01

    The quality of anaerobic sludge and struvite from black water treatment system, aerobic sludge from grey water treatment system and effluents of both systems was assessed for organic micropollutant content in order to ensure safety when reusing these products. Use of anaerobic black water sludge and struvite as soil amendments is recommended based on the low micropollutant content. Aerobic grey water sludge is recommended for disposal, because of the relatively high micropollutant concentrations, exceeding those in sewage sludge. Effluents of black and grey water treatment systems require post-treatment prior to reuse, because the measured micropollutant concentrations in the effluents are above ecotoxicological thresholds. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Phase transformation of calcium oxalate dihydrate-monohydrate: Effects of relative humidity and new spectroscopic data

    NASA Astrophysics Data System (ADS)

    Conti, Claudia; Casati, Marco; Colombo, Chiara; Realini, Marco; Brambilla, Luigi; Zerbi, Giuseppe

    2014-07-01

    New data on vibrational properties of calcium oxalates and their controversial transformation mechanism are presented. We have focused on whewellite (CaC2O4·H2O) and weddellite [CaC2O4·(2 + x) H2O], the most common phases of calcium oxalate; these compounds occur in many organisms, in kidney stones and in particular kinds of films found on the surface of many works of art. Low temperature experiments carried out by Fourier transform infrared spectroscopy have highlighted both the high structural order in the crystalline state of whewellite and the disordered distribution of the zeolitic water molecules in weddellite. The synthesised nanocrystals of weddellite have been kept under different hygrometric conditions in order to study, by X-ray powder diffraction, the role of “external” water molecules on their stability. Moreover, in order to identify the different kinds of water molecules, a re-investigation, supported by quantum chemical calculations, of the observed vibrational spectra (IR and Raman) of whewellite has been conducted.

  16. Household Water Disinfection in Hurricane-Affected Communities of Louisiana: Implications for Disaster Preparedness for the General Public

    PubMed Central

    Ram, Pavani K.; Blanton, Elizabeth; Klinghoffer, Debra; Platek, Mary; Piper, Janet; Straif-Bourgeois, Susanne; Bonner, Matthew R.; Mintz, Eric D.

    2007-01-01

    Objectives. Thousands of Louisiana residents were asked to boil water because of widespread disruptions in electricity and natural gas services after Hurricane Rita. We sought to assess awareness of boil water orders and familiarity with household water disinfection techniques other than boiling. Methods. We conducted a cross-sectional survey in randomly selected mobile home communities in Louisiana. Results. We interviewed 196 respondents from 8 communities, which had boil water orders instituted. Of 97 who were home while communities were still under orders to boil water, 30 (31%) were aware of the orders and, of those, 24 (80%) said the orders were active while they were living at home; of the 24, 10 (42%) reported boiling water. Overall, 163 (83%) respondents were aware of a method of water disinfection at the household level: boiling (78%), chlorination (27%), and filtration (25%); 87% had a container of chlorine bleach at home. Conclusions. Few hurricane-affected respondents were aware of boil water orders and of alternate water disinfection techniques. Most had access to chlorine and could have practiced household chlorination if disruption in natural gas and electricity made boiling impossible. PMID:17413065

  17. Riverbank filtration for the treatment of highly turbid Colombian rivers

    NASA Astrophysics Data System (ADS)

    Gutiérrez, Juan Pablo; van Halem, Doris; Rietveld, Luuk

    2017-05-01

    The poor quality of many Colombian surface waters forces us to seek alternative, sustainable treatment solutions with the ability to manage peak pollution events and to guarantee the uninterrupted provision of safe drinking water to the population. This review assesses the potential of using riverbank filtration (RBF) for the highly turbid and contaminated waters in Colombia, emphasizing water quality improvement and the influence of clogging by suspended solids. The suspended sediments may be favorable for the improvement of the water quality, but they may also reduce the production yield capacity. The cake layer must be balanced by scouring in order for an RBF system to be sustainable. The infiltration rate must remain high enough throughout the river-aquifer interface to provide the water quantity needed, and the residence time of the contaminants must be sufficient to ensure adequate water quality. In general, RBF seems to be a technology appropriate for use in highly turbid and contaminated surface rivers in Colombia, where improvements are expected due to the removal of turbidity, pathogens and to a lesser extent inorganics, organic matter and micro-pollutants. RBF has the potential to mitigate shock loads, thus leading to the prevention of shutdowns of surface water treatment plants. In addition, RBF, as an alternative pretreatment step, may provide an important reduction in chemical consumption, considerably simplifying the operation of the existing treatment processes. However, clogging and self-cleansing issues must be studied deeper in the context of these highly turbid waters to evaluate the potential loss of abstraction capacity yield as well as the development of different redox zones for efficient contaminant removal.

  18. High resolution modelling of extreme precipitation events in urban areas

    NASA Astrophysics Data System (ADS)

    Siemerink, Martijn; Volp, Nicolette; Schuurmans, Wytze; Deckers, Dave

    2015-04-01

    The present day society needs to adjust to the effects of climate change. More extreme weather conditions are expected, which can lead to longer periods of drought, but also to more extreme precipitation events. Urban water systems are not designed for such extreme events. Most sewer systems are not able to drain the excessive storm water, causing urban flooding. This leads to high economic damage. In order to take appropriate measures against extreme urban storms, detailed knowledge about the behaviour of the urban water system above and below the streets is required. To investigate the behaviour of urban water systems during extreme precipitation events new assessment tools are necessary. These tools should provide a detailed and integral description of the flow in the full domain of overland runoff, sewer flow, surface water flow and groundwater flow. We developed a new assessment tool, called 3Di, which provides detailed insight in the urban water system. This tool is based on a new numerical methodology that can accurately deal with the interaction between overland runoff, sewer flow and surface water flow. A one-dimensional model for the sewer system and open channel flow is fully coupled to a two-dimensional depth-averaged model that simulates the overland flow. The tool uses a subgrid-based approach in order to take high resolution information of the sewer system and of the terrain into account [1, 2]. The combination of using the high resolution information and the subgrid based approach results in an accurate and efficient modelling tool. It is now possible to simulate entire urban water systems using extreme high resolution (0.5m x 0.5m) terrain data in combination with a detailed sewer and surface water network representation. The new tool has been tested in several Dutch cities, such as Rotterdam, Amsterdam and The Hague. We will present the results of an extreme precipitation event in the city of Schiedam (The Netherlands). This city deals with significant soil consolidation and the low-lying areas are prone to urban flooding. The simulation results are compared with measurements in the sewer network. References [1] Guus S. Stelling G.S., 2012. Quadtree flood simulations with subgrid digital elevation models. Water Management 165 (WM1):1329-1354. [2] Vincenzo Cassuli and Guus S. Stelling, 2013. A semi-implicit numerical model for urban drainage systems. International Journal for Numerical Methods in Fluids. Vol. 73:600-614. DOI: 10.1002/fld.3817

  19. Are Longitudinal Patterns of Bacterial Community Composition and Dissolved Organic Matter Composition Linked Across a River Continuum? (Invited)

    NASA Astrophysics Data System (ADS)

    Mosher, J.; Kaplan, L. A.; Kan, J.; Findlay, R. H.; Podgorski, D. C.; McKenna, A. M.; Branan, T. L.; Griffith, C.

    2013-12-01

    The River Continuum Concept (RCC), an early meta-ecosystem idea, was developed without the benefit of new frontiers in molecular microbial ecology and ultra-high resolution mass spectrometry. We have applied technical advances in these areas to address a hypothesis implicit in the RCC that the upstream legacy of DOM processing contributes to the structure and function of downstream bacterial communities. DOM molecular structure and microbial community structure were measured across river networks within three distinct forested catchments. High-throughput pyrosequencing of bacterial 16S rRNA amplicons and phospholipid fatty acid analysis were used to characterize bacterial communities, and ultra-high resolution Fourier transform ion cyclotron resonance mass spectrometry characterized the molecular composition of stream water DOM. Total microbial biomass varied among river networks but showed a trend of decreasing biomass in sediment with increasing stream order. There were distinct shifts in bacterial community structure and a trend of decreasing richness was observed traveling downstream in both sediment and epilithic habitats. The bacterial richness in the first order stream sediment habitats was 7728 genera which decreased to 6597 genera in the second order sites and 4867 genera in the third order streams. The richness in the epilithic biofilm habitats was 2830 genera in the first order, 2322 genera in the second order and 1629 genera in the third order sites. Over 45% of the sediment biofilm genera and 37% of the epilithic genera were found in all three orders. In addition to shifts in bacterial richness, we observed a longitudinal shift in bacterial functional-types. In the sediment biofilms, Rhodoplanes spp. (containing rhodopsin pigment) and Bradyrhizobium spp. (nitrogen fixing bacteria) were predominately found in the heavily forested first order streams, while the cyanobacteria Limnothrix spp. was dominant in the second order streams. The third order streams had higher abundances of Sphingomonadaceae spp. and Nordella spp. (both Alphaproteobacteria). The cyanobacteria Chamaesiphon spp. was observed in highest abundance in the first and second order streams of the rock biofilm samples and the cyanobacteria Oscillatoria spp. was in highest abundance in the third order streams. Stream water samples from all orders had high lignin/tannin content and were enriched with carboxylic-rich alicyclic molecules (CRAM). There was an observable shift in in the molecular weight and relative abundance of the CRAM molecules with the CRAM molecules becoming less abundant and having lower molecular weight following the downstream gradient. Multivariate statistical analyses correlated the longitudinal patterns of changes in bacterial community structure to the DOM molecular structure and geochemical parameters across the river continuum.

  20. Measuring sporadic gastrointestinal illness associated with drinking water - an overview of methodologies.

    PubMed

    Bylund, John; Toljander, Jonas; Lysén, Maria; Rasti, Niloofar; Engqvist, Jannes; Simonsson, Magnus

    2017-06-01

    There is an increasing awareness that drinking water contributes to sporadic gastrointestinal illness (GI) in high income countries of the northern hemisphere. A literature search was conducted in order to review: (1) methods used for investigating the effects of public drinking water on GI; (2) evidence of possible dose-response relationship between sporadic GI and drinking water consumption; and (3) association between sporadic GI and factors affecting drinking water quality. Seventy-four articles were selected, key findings and information gaps were identified. In-home intervention studies have only been conducted in areas using surface water sources and intervention studies in communities supplied by ground water are therefore needed. Community-wide intervention studies may constitute a cost-effective alternative to in-home intervention studies. Proxy data that correlate with GI in the community can be used for detecting changes in the incidence of GI. Proxy data can, however, not be used for measuring the prevalence of illness. Local conditions affecting water safety may vary greatly, making direct comparisons between studies difficult unless sufficient knowledge about these conditions is acquired. Drinking water in high-income countries contributes to endemic levels of GI and there are public health benefits for further improvements of drinking water safety.

  1. A flexible, robust and antifouling asymmetric membrane based on ultra-long ceramic/polymeric fibers for high-efficiency separation of oil/water emulsions.

    PubMed

    Wang, Kui; Yiming, Wubulikasimu; Saththasivam, Jayaprakash; Liu, Zhaoyang

    2017-07-06

    Polymeric and ceramic asymmetric membranes have dominated commercial membranes for water treatment. However, polymeric membranes are prone to becoming fouled, while ceramic membranes are mechanically fragile. Here, we report a novel concept to develop asymmetric membranes based on ultra-long ceramic/polymeric fibers, with the combined merits of good mechanical stability, excellent fouling resistance and high oil/water selectivity, in order to meet the stringent requirements for practical oil/water separation. The ultra-long dimensions of ceramic nanofibers/polymeric microfibers endow this novel membrane with mechanical flexibility and robustness, due to the integrated and intertwined structure. This membrane is capable of separating oil/water emulsions with high oil-separation efficiency (99.9%), thanks to its nanoporous selective layer made of ceramic nanofibers. Further, this membrane also displays superior antifouling properties due to its underwater superoleophobicity and ultra-low oil adhesion of the ceramic-based selective layer. This membrane exhibits high water permeation flux (6.8 × 10 4 L m -2 h -1 bar -1 ) at low operation pressures, which is attributed to its 3-dimensional (3D) interconnected fiber-based structure throughout the membrane. In addition, the facile fabrication process and inexpensive materials required for this membrane suggest its significant potential for industrial applications.

  2. Tunable water desalination across Graphene Oxide Framework membranes

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

    Nicolai, Adrien; Sumpter, Bobby G; Meunier, V.

    2014-01-01

    The performance of graphene oxide framework (GOF) membranes for water desalination is assessed using classical molecular dynamics (MD) simulations. The coupling between water permeability and salt rejection GOF membranes is studied as a function of linker concentration n, thickness h and applied pressure DP. The simulations reveal that water permeability in GOF-(n,h) membranes can be tuned from 5 (n = 32 and h = 6.5 nm) to 400 L/cm2/day/MPa (n = 64 and h = 2.5 nm) and follows the law Cnh an . For a given pore size (n = 16 or 32), water permeability of GOF membranes increasesmore » when the pore spacing decreases, whereas for a given pore spacing (n = 32 or 64), water permeability increases by up to two orders of magnitude when the pore size increases. Furthermore, for linker concentrations n 32, the high water permeability corresponds to a 100% salt rejection, elevating this type of GOF membrane as an ideal candidate for water desalination. Compared to experimental performance of reverse osmosis membranes, our calculations suggest that under the same conditions of applied pressure and characteristics of membranes (DP 10 MPa and h 100 nm), one can expect a perfect salt rejection coupled to a water permeability two orders of magnitude higher than existing technologies, i.e., from a few cL/cm2/day/MPa to a few L/cm2/day/MPa.« less

  3. Induction of long-lived room temperature phosphorescence of carbon dots by water in hydrogen-bonded matrices.

    PubMed

    Li, Qijun; Zhou, Ming; Yang, Mingyang; Yang, Qingfeng; Zhang, Zhixun; Shi, Jing

    2018-02-21

    Phosphorescence shows great potential for application in bioimaging and ion detection because of its long-lived luminescence and high signal-to-noise ratio, but establishing phosphorescence emission in aqueous environments remains a challenge. Herein, we present a general design strategy that effectively promotes phosphorescence by utilising water molecules to construct hydrogen-bonded networks between carbon dots (CDs) and cyanuric acid (CA). Interestingly, water molecules not only cause no phosphorescence quenching but also greatly enhance the phosphorescence emission. This enhancement behaviour can be explained by the fact that the highly ordered bound water on the CA particle surface can construct robust bridge-like hydrogen-bonded networks between the CDs and CA, which not only effectively rigidifies the C=O bonds of the CDs but also greatly enhances the rigidity of the entire system. In addition, the CD-CA suspension exhibits a high phosphorescence lifetime (687 ms) and is successfully applied in ion detection based on its visible phosphorescence.

  4. Large Area, High Reliability Liquid Dielectric Systems: Provisional Design Criteria and Experimental Approaches to More Realistic Projections

    DTIC Science & Technology

    2001-06-01

    illustrated in Fig. 1, where the regions of highly-stressed electrodes in the water and oil are indicated. There will be of the order first tests...will be on oil. We will be able to test only ∧ 104 cm2 of electrode compared with ~108 cm2 in the power plant, and even if we are able to accelerate...the data in Ref. 3 further illustrates this question and how it might be tested. For a 100 cm2 electrode area in water, the stress cor- responding to

  5. Watershed prioritization in the upper Han River basin for soil and water conservation in the South-to-North Water Transfer Project (middle route) of China.

    PubMed

    Wu, Haibing

    2018-01-01

    Watershed prioritization with the objective of identifying critical areas to undertake soil and water conservation measures was conducted in the upper Han River basin, the water source area of approximately 95,000 km 2 for the middle route of China's South-to-North Water Transfer Project. Based on the estimated soil erosion intensity in uplands and clustering analysis of measured nutrient concentrations in rivers, the basin was grouped into very-high-, high-, moderate-, and low-priority regions for water and soil conservation, respectively. The results indicated that soil erosion was primarily controlled by topography, and nutrients in rivers were associated with land use and land cover in uplands. Also, there was large spatial disparity between soil erosion intensity in the uplands and nutrient concentrations in the rivers across the basin. Analysis was then performed to prioritize the basin by the integration of the soil erosion intensity and water quality on a GIS platform in order to identify critical areas for water and soil conservation in the basin. The identified high-priority regions which occupy 5.74% of the drainage areas need immediate attention for soil and water conservation treatments, of which 5.28% is critical for soil erosion prevention and 0.46% for water conservation. Understandings of the basin environment and pollutant loading with spatial explicit are critical to the soil and water resource conservation for the interbasin water transfer project.

  6. Nanostructured polymer membranes for proton conduction

    DOEpatents

    Balsara, Nitash Pervez; Park, Moon Jeong

    2013-06-18

    Polymers having an improved ability to entrain water are characterized, in some embodiments, by unusual humidity-induced phase transitions. The described polymers (e.g., hydrophilically functionalized block copolymers) have a disordered state and one or more ordered states (e.g., a lamellar state, a gyroid state, etc.). In one aspect, the polymers are capable of undergoing a disorder-to-order transition while the polymer is exposed to an increasing temperature at a constant relative humidity. In some aspects the polymer includes a plurality of portions, wherein a first portion forms proton-conductive channels within the membrane and wherein the channels have a width of less than about 6 nm. The described polymers are capable of entraining and preserving water at high temperature and low humidity. Surprisingly, in some embodiments, the polymers are capable of entraining greater amounts of water with the increase of temperature. The polymers can be used in Polymer Electrolyte Membranes in fuel cells.

  7. Cavitation propagation in water under tension

    NASA Astrophysics Data System (ADS)

    Noblin, Xavier; Yip Cheung Sang, Yann; Pellegrin, Mathieu; Materials and Complex Fluids Team

    2012-11-01

    Cavitation appears when pressure decreases below vapor pressure, generating vapor bubbles. It can be obtain in dynamical ways (acoustic, hydraulic) but also in quasi-static conditions. This later case is often observed in nature, in trees, or during the ejection of ferns spores. We study the cavitation bubbles nucleation dynamics and its propagation in a confined microfabricated media. This later is an ordered array of microcavities made in hydrogel filled with water. When the system is put into dry air, it dehydrates, water leaves the cavities and tension (negative pressure) builds in the cavities. This can be sustained up to a critical pressure (of order -20 MPa), then cavitation bubbles appear. We follow the dynamics using ultra high speed imaging. Events with several bubbles cavitating in a few microseconds could be observed along neighboring cells, showing a propagation phenomenon that we discuss. ANR CAVISOFT 2010-JCJC-0407 01.

  8. Simulation of Shallow Water Jets with a Unified Element-based Continuous/Discontinuous Galerkin Model with Grid Flexibility on the Sphere

    DTIC Science & Technology

    2013-01-01

    is the derivative of the N th-order Legendre polynomial . Given these definitions, the one-dimensional Lagrange polynomials hi(ξ) are hi(ξ) = − 1 N(N...2. Detail of one interface patch in the northern hemisphere. The high-order Legendre -Gauss-Lobatto (LGL) points are added to the linear grid by...smaller ones by a Lagrange polynomial of order nI . The number of quadrilateral elements and grid points of the final grid are then given by Np = 6(N

  9. [Limnetic zooplankton run-off a high-head dam and their fate in a river with high current velocity (case of the Krasnoiarsk hydroelectric power station on the Yenisei river].

    PubMed

    Dubovskaia, O P; Gladyshev, M I; Makhutova, O N

    2004-01-01

    The vertical distribution of net zooplankton in head-water of Krasnoyarsk hydroelectric power station and its horizontal distribution in the tail-water were studied during two years in winter and summer seasons. In order to distinguish living and dead individuals the special staining was used. It was revealed that on average 77% of living plankton pass through high-head dam with deep water scoop to the tailwater. While passing through dam aggregates some individuals of the reservoir plankton are traumatized and die, that results in some increase of portion of dead individuals in the tail water near dam (from 3 to 6%). Alive zooplankton passed through the dam aggregates is eliminated under the Upper Yenisei highly turbulent conditions. There is approximately 10% of it in 32 km from the dam if compare with biomass in 20-40 m layer of reservoir, the portion of dead increases to 11%. The biomass of zooplankton suspended in the water column of the tail-water sometimes increases (till > 1 g/m3) due to large Copepoda Heteroscope borealis, which inhabits near-bottom and near-shore river zones and can be found in the central part of the river during reproductive period. Limnetic zooplankton from the reservoir cannot be considered as important food for planktivores in the tail-water.

  10. Heat, Mass and Aerosol Transfers in Spray Conditions for Containment Application

    NASA Astrophysics Data System (ADS)

    Porcheron, Emmanuel; Lemaitre, Pascal; Nuboer, Amandine; Vendel, Jacques

    TOSQAN is an experimental program undertaken by the Institut de Radioprotection et de Surété Nucleaire (IRSN) in order to perform thermal hydraulic containment studies. The TOSQAN facility is a large enclosure devoted to simulating typical accidental thermal hydraulic flow conditions in nuclear Pressurized Water Reactor (PWR) containment. The TOSQAN facility, which is highly instrumented with non-intrusive optical diagnostics, is particularly adapted to nuclear safety CFD code validation. The present work is devoted to studying the interaction of a water spray injection used as a mitigation means in order to reduce the gas pressure and temperature in the containment, to produce gases mixing and washout of fission products. In order to have a better understanding of heat and mass transfers between spray droplets and the gas mixture, and to analyze mixing effects due to spray activation, we performed detailed characterization of the two-phase flow.

  11. Design and function of biomimetic multilayer water purification membranes

    PubMed Central

    Ling, Shengjie; Qin, Zhao; Huang, Wenwen; Cao, Sufeng; Kaplan, David L.; Buehler, Markus J.

    2017-01-01

    Multilayer architectures in water purification membranes enable increased water throughput, high filter efficiency, and high molecular loading capacity. However, the preparation of membranes with well-organized multilayer structures, starting from the nanoscale to maximize filtration efficiency, remains a challenge. We report a complete strategy to fully realize a novel biomaterial-based multilayer nanoporous membrane via the integration of computational simulation and experimental fabrication. Our comparative computational simulations, based on coarse-grained models of protein nanofibrils and mineral plates, reveal that the multilayer structure can only form with weak interactions between nanofibrils and mineral plates. We demonstrate experimentally that silk nanofibril (SNF) and hydroxyapatite (HAP) can be used to fabricate highly ordered multilayer membranes with nanoporous features by combining protein self-assembly and in situ biomineralization. The production is optimized to be a simple and highly repeatable process that does not require sophisticated equipment and is suitable for scaled production of low-cost water purification membranes. These membranes not only show ultrafast water penetration but also exhibit broad utility and high efficiency of removal and even reuse (in some cases) of contaminants, including heavy metal ions, dyes, proteins, and other nanoparticles in water. Our biomimetic design and synthesis of these functional SNF/HAP materials have established a paradigm that could lead to the large-scale, low-cost production of multilayer materials with broad spectrum and efficiency for water purification, with applications in wastewater treatment, biomedicine, food industry, and the life sciences. PMID:28435877

  12. Design and function of biomimetic multilayer water purification membranes.

    PubMed

    Ling, Shengjie; Qin, Zhao; Huang, Wenwen; Cao, Sufeng; Kaplan, David L; Buehler, Markus J

    2017-04-01

    Multilayer architectures in water purification membranes enable increased water throughput, high filter efficiency, and high molecular loading capacity. However, the preparation of membranes with well-organized multilayer structures, starting from the nanoscale to maximize filtration efficiency, remains a challenge. We report a complete strategy to fully realize a novel biomaterial-based multilayer nanoporous membrane via the integration of computational simulation and experimental fabrication. Our comparative computational simulations, based on coarse-grained models of protein nanofibrils and mineral plates, reveal that the multilayer structure can only form with weak interactions between nanofibrils and mineral plates. We demonstrate experimentally that silk nanofibril (SNF) and hydroxyapatite (HAP) can be used to fabricate highly ordered multilayer membranes with nanoporous features by combining protein self-assembly and in situ biomineralization. The production is optimized to be a simple and highly repeatable process that does not require sophisticated equipment and is suitable for scaled production of low-cost water purification membranes. These membranes not only show ultrafast water penetration but also exhibit broad utility and high efficiency of removal and even reuse (in some cases) of contaminants, including heavy metal ions, dyes, proteins, and other nanoparticles in water. Our biomimetic design and synthesis of these functional SNF/HAP materials have established a paradigm that could lead to the large-scale, low-cost production of multilayer materials with broad spectrum and efficiency for water purification, with applications in wastewater treatment, biomedicine, food industry, and the life sciences.

  13. Stratified flows with variable density: mathematical modelling and numerical challenges.

    NASA Astrophysics Data System (ADS)

    Murillo, Javier; Navas-Montilla, Adrian

    2017-04-01

    Stratified flows appear in a wide variety of fundamental problems in hydrological and geophysical sciences. They may involve from hyperconcentrated floods carrying sediment causing collapse, landslides and debris flows, to suspended material in turbidity currents where turbulence is a key process. Also, in stratified flows variable horizontal density is present. Depending on the case, density varies according to the volumetric concentration of different components or species that can represent transported or suspended materials or soluble substances. Multilayer approaches based on the shallow water equations provide suitable models but are not free from difficulties when moving to the numerical resolution of the governing equations. Considering the variety of temporal and spatial scales, transfer of mass and energy among layers may strongly differ from one case to another. As a consequence, in order to provide accurate solutions, very high order methods of proved quality are demanded. Under these complex scenarios it is necessary to observe that the numerical solution provides the expected order of accuracy but also converges to the physically based solution, which is not an easy task. To this purpose, this work will focus in the use of Energy balanced augmented solvers, in particular, the Augmented Roe Flux ADER scheme. References: J. Murillo , P. García-Navarro, Wave Riemann description of friction terms in unsteady shallow flows: Application to water and mud/debris floods. J. Comput. Phys. 231 (2012) 1963-2001. J. Murillo B. Latorre, P. García-Navarro. A Riemann solver for unsteady computation of 2D shallow flows with variable density. J. Comput. Phys.231 (2012) 4775-4807. A. Navas-Montilla, J. Murillo, Energy balanced numerical schemes with very high order. The Augmented Roe Flux ADER scheme. Application to the shallow water equations, J. Comput. Phys. 290 (2015) 188-218. A. Navas-Montilla, J. Murillo, Asymptotically and exactly energy balanced augmented flux-ADER schemes with application to hyperbolic conservation laws with geometric source terms, J. Comput. Phys. 317 (2016) 108-147. J. Murillo and A. Navas-Montilla, A comprehensive explanation and exercise of the source terms in hyperbolic systems using Roe type solutions. Application to the 1D-2D shallow water equations, Advances in Water Resources 98 (2016) 70-96.

  14. Controls on old and new water contributions to stream flow at some nested catchments in Vermont, USA

    USGS Publications Warehouse

    Shanley, J.B.; Kendall, C.; Smith, T.E.; Wolock, D.M.; McDonnell, Jeffery J.

    2002-01-01

    Factors controlling the partitioning of old and new water contributions to stream flow were investigated for three events in four catchments (three of which were nested) at Sleepers River Research Watershed in Danville, Vermont. In the 1993 snowmelt period, two-component isotopic hydrograph separations showed that new water (meltwater) inputs to the stream ranged widely from 41 to 74%, and increased with catchment size (41 to 11 125 ha) (with one exception) and with open land cover (0-73%). Peak dissolved organic carbon concentrations and relative alkalinity dilution in stream water ranked in the same order among catchments as the new water fractions, suggesting that new water followed shallow flow paths. During the 1994 snowmelt, despite similar timing and magnitude of melt inputs, the new-water contribution to stream flow ranged only from 30 to 36% in the four catchments. We conclude that the uncommonly high and variable new water fractions in streamwater during the 1993 melt were caused by direct runoff of meltwater over frozen ground, which was prevalent in open land areas during the 1993 winter. In a high-intensity summer rainstorm in 1993, new water fractions were smaller relative to the 1993 snowmelt, ranging from 28 to 46%, but they ranked in the identical catchment order. Reconciliation of the contrasting patterns of new-old water partitioning in the three events appears to require an explanation that invokes multiple processes and effects, including: 1 topographically controlled increase in surface-saturated area with increasing catchment size; 2 direct runoff over frozen ground; 3 low infiltration in agriculturally compacted soils; 4 differences in soil transmissivity, which may be more relevant under dry antecedent conditions. These data highlight some of the difficulties faced by catchment hydrologists in formulating a theory of runoff generation at varying basin scales. Copyright ?? 2002 John Wiley and Sons, Ltd.

  15. Controls on old and new water contributions to stream flow at some nested catchments in Vermont, USA

    NASA Astrophysics Data System (ADS)

    Shanley, James B.; Kendall, Carol; Smith, Thor E.; Wolock, David M.; McDonnell, Jeffrey J.

    2002-02-01

    Factors controlling the partitioning of old and new water contributions to stream flow were investigated for three events in four catchments (three of which were nested) at Sleepers River Research Watershed in Danville, Vermont. In the 1993 snowmelt period, two-component isotopic hydrograph separations showed that new water (meltwater) inputs to the stream ranged widely from 41 to 74%, and increased with catchment size (41 to 11 125 ha) (with one exception) and with open land cover (0-73%). Peak dissolved organic carbon concentrations and relative alkalinity dilution in stream water ranked in the same order among catchments as the new water fractions, suggesting that new water followed shallow flow paths. During the 1994 snowmelt, despite similar timing and magnitude of melt inputs, the new-water contribution to stream flow ranged only from 30 to 36% in the four catchments. We conclude that the uncommonly high and variable new water fractions in streamwater during the 1993 melt were caused by direct runoff of meltwater over frozen ground, which was prevalent in open land areas during the 1993 winter. In a high-intensity summer rainstorm in 1993, new water fractions were smaller relative to the 1993 snowmelt, ranging from 28 to 46%, but they ranked in the identical catchment order. Reconciliation of the contrasting patterns of new-old water partitioning in the three events appears to require an explanation that invokes multiple processes and effects, including: 1.topographically controlled increase in surface-saturated area with increasing catchment size;2.direct runoff over frozen ground;3.low infiltration in agriculturally compacted soils;4.differences in soil transmissivity, which may be more relevant under dry antecedent conditions. These data highlight some of the difficulties faced by catchment hydrologists in formulating a theory of runoff generation at varying basin scales.

  16. Removal of glyphosate herbicide from water using biopolymer membranes.

    PubMed

    Carneiro, Rafael T A; Taketa, Thiago B; Gomes Neto, Reginaldo J; Oliveira, Jhones L; Campos, Estefânia V R; de Moraes, Mariana A; da Silva, Camila M G; Beppu, Marisa M; Fraceto, Leonardo F

    2015-03-15

    Enormous amounts of pesticides are manufactured and used worldwide, some of which reach soils and aquatic systems. Glyphosate is a non-selective herbicide that is effective against all types of weeds and has been used for many years. It can therefore be found as a contaminant in water, and procedures are required for its removal. This work investigates the use of biopolymeric membranes prepared with chitosan (CS), alginate (AG), and a chitosan/alginate combination (CS/AG) for the adsorption of glyphosate present in water samples. The adsorption of glyphosate by the different membranes was investigated using the pseudo-first order and pseudo-second order kinetic models, as well as the Langmuir and Freundlich isotherm models. The membranes were characterized regarding membrane solubility, swelling, mechanical, chemical and morphological properties. The results of kinetics experiments showed that adsorption equilibrium was reached within 4 h and that the CS membrane presented the best adsorption (10.88 mg of glyphosate/g of membrane), followed by the CS/AG bilayer (8.70 mg of glyphosate/g of membrane). The AG membrane did not show any adsorption capacity for this herbicide. The pseudo-second order model provided good fits to the glyphosate adsorption data on CS and CS/AG membranes, with high correlation coefficient values. Glyphosate adsorption by the membranes could be fitted by the Freundlich isotherm model. There was a high affinity between glyphosate and the CS membrane and moderate affinity in the case of the CS/AG membrane. Physico-chemical characterization of the membranes showed low values of solubility in water, indicating that the membranes are stable and not soluble in water. The SEM and AFM analysis showed evidence of the presence of glyphosate on CS membranes and on chitosan face on CS/AG membranes. The results showed that the glyphosate herbicide can be adsorbed by chitosan membranes and the proposed membrane-based methodology was successfully used to treat a water sample contaminated with glyphosate. Biopolymer membranes therefore potentially offer a versatile method to eliminate agricultural chemicals from water supplies. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Regulation of water balance in mangroves

    PubMed Central

    Reef, Ruth; Lovelock, Catherine E.

    2015-01-01

    Background Mangroves are a group of highly salt-tolerant woody plants. The high water use efficiency of mangroves under saline conditions suggests that regulation of water transport is a crucial component of their salinity tolerance. Scope This review focuses on the processes that contribute to the ability of mangroves to maintain water uptake and limit water loss to the soil and the atmosphere under saline conditions, from micro to macro scales. These processes include: (1) efficient filtering of the incoming water to exclude salt; (2) maintenance of internal osmotic potentials lower than that of the rhizosphere; (3) water-saving properties; and (4) efficient exploitation of less-saline water sources when these become available. Conclusions Mangroves are inherently plastic and can change their structure at the root, leaf and stand levels in response to salinity in order to exclude salt from the xylem stream, maintain leaf hydraulic conductance, avoid cavitation and regulate water loss (e.g. suberization of roots and alterations of leaf size, succulence and angle, hydraulic anatomy and biomass partitioning). However, much is still unknown about the regulation of water uptake in mangroves, such as how they sense and respond to heterogeneity in root zone salinity, the extent to which they utilize non-stomatally derived CO2 as a water-saving measure and whether they can exploit atmospheric water sources. PMID:25157072

  18. Large-scale hydrological modeling for calculating water stress indices: implications of improved spatiotemporal resolution, surface-groundwater differentiation, and uncertainty characterization.

    PubMed

    Scherer, Laura; Venkatesh, Aranya; Karuppiah, Ramkumar; Pfister, Stephan

    2015-04-21

    Physical water scarcities can be described by water stress indices. These are often determined at an annual scale and a watershed level; however, such scales mask seasonal fluctuations and spatial heterogeneity within a watershed. In order to account for this level of detail, first and foremost, water availability estimates must be improved and refined. State-of-the-art global hydrological models such as WaterGAP and UNH/GRDC have previously been unable to reliably reflect water availability at the subbasin scale. In this study, the Soil and Water Assessment Tool (SWAT) was tested as an alternative to global models, using the case study of the Mississippi watershed. While SWAT clearly outperformed the global models at the scale of a large watershed, it was judged to be unsuitable for global scale simulations due to the high calibration efforts required. The results obtained in this study show that global assessments miss out on key aspects related to upstream/downstream relations and monthly fluctuations, which are important both for the characterization of water scarcity in the Mississippi watershed and for water footprints. Especially in arid regions, where scarcity is high, these models provide unsatisfying results.

  19. Water, a host of life

    NASA Astrophysics Data System (ADS)

    Niculescu, E.; Maghiar, R.

    2012-04-01

    An interdisciplinary study of water realized in High Schools of Bucharest and Oradea The paper studies the importance and the properties of water from different points of view. In the curricula the water is studied by sciences as Chemistry, Physics, Biology, Geography and Environmental Sciences, but the water is important also for History, Economy, Sociology, Religion, Arts, Sport, and so on. The students from "C.A.Rosetti High-school" from Bucharest and "Mihai Viteazul" from Oradea, guided by their teachers realized some interesting studies about water as physical, biological and chemical properties but also about economical importance of the water in our life, or about the aesthetic value of the water. The final products (CD-s, PowerPoint presentations, movies, drawings, posters and so on) are realized during the lessons from the curricula but also in non-formal education activities. So the students accomplished some research about water in specialised institutes, but also in the middle of nature. They studied the plants, insects and animals living in wetland areas. The students went to the springs, rivers , lakes, the Danube Delta and to the Black Sea and after that they organised workshops and seminars in order to disseminate their work.

  20. Modeling Household Water Consumption in a Hydro-Institutional System - The Case of Jordan

    NASA Astrophysics Data System (ADS)

    Klassert, C. J. A.; Gawel, E.; Klauer, B.; Sigel, K.

    2014-12-01

    Jordan faces an archetypal combination of high water scarcity, with a per capita water availability of around 150 CM per year significantly below the absolute scarcity threshold of 500 CM, and strong population growth, especially due to the Syrian refugee crisis. This poses a severe challenge to the already strained institutions in the Jordanian water sector. The Stanford-led G8 Belmont Forum project "Integrated Analysis of Freshwater Resources Sustainability in Jordan" aims at analyzing the potential role of water sector institutions in the pursuit of a sustainable freshwater system performance. In order to do so, the project develops a coupled hydrological and agent-based model, allowing for the exploration of physical as well as socio-economic and institutional scenarios for Jordan's water sector. The part of this integrated model in focus here is the representation of household behavior in Jordan's densely populated capital Amman. Amman's piped water supply is highly intermittent, which also affects its potability. Therefore, Amman's citizens rely on various decentralized modes of supply, depending on their socio-economic characteristics. These include water storage in roof-top and basement tanks, private tanker supply, and the purchase of bottled water. Capturing this combination of centralized and decentralized supply modes is important for an adequate representation of water consumption behavior: Firstly, it will affect the impacts of supply-side and demand-side policies, such as reductions of non-revenue water (including illegal abstractions), the introduction of continuous supply, support for storage enhancements, and water tariff reforms. Secondly, it is also necessary to differentiate the impacts of any policy on the different socio-economic groups in Amman. In order to capture the above aspects of water supply, our model is based on the tiered supply curve approach, developed by Srinivasan et al. in 2011 to model a similar situation in Chennai, India. To tailor our model to the situation in Amman, we rely on sectoral data, existing literature analyses and expert discussions with Jordanian water sector representatives. Our modeling approach allows us to directly compare policies affecting both centralized and decentralized elements of the system within a common framework.

  1. Vancomycin-Resistant Enterococci and Bacterial Community Structure following a Sewage Spill into an Aquatic Environment.

    PubMed

    Young, Suzanne; Nayak, Bina; Sun, Shan; Badgley, Brian D; Rohr, Jason R; Harwood, Valerie J

    2016-09-15

    Sewage spills can release antibiotic-resistant bacteria into surface waters, contributing to environmental reservoirs and potentially impacting human health. Vancomycin-resistant enterococci (VRE) are nosocomial pathogens that have been detected in environmental habitats, including soil, water, and beach sands, as well as wildlife feces. However, VRE harboring vanA genes that confer high-level resistance have infrequently been found outside clinical settings in the United States. This study found culturable Enterococcus faecium harboring the vanA gene in water and sediment for up to 3 days after a sewage spill, and the quantitative PCR (qPCR) signal for vanA persisted for an additional week. Culturable levels of enterococci in water exceeded recreational water guidelines for 2 weeks following the spill, declining about five orders of magnitude in sediments and two orders of magnitude in the water column over 6 weeks. Analysis of bacterial taxa via 16S rRNA gene sequencing showed changes in community structure through time following the sewage spill in sediment and water. The spread of opportunistic pathogens harboring high-level vancomycin resistance genes beyond hospitals and into the broader community and associated habitats is a potential threat to public health, requiring further studies that examine the persistence, occurrence, and survival of VRE in different environmental matrices. Vancomycin-resistant enterococci (VRE) are harmful bacteria that are resistant to the powerful antibiotic vancomycin, which is used as a last resort against many infections. This study followed the release of VRE in a major sewage spill and their persistence over time. Such events can act as a means of spreading vancomycin-resistant bacteria in the environment, which can eventually impact human health. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  2. Vancomycin-Resistant Enterococci and Bacterial Community Structure following a Sewage Spill into an Aquatic Environment

    PubMed Central

    Young, Suzanne; Nayak, Bina; Sun, Shan; Badgley, Brian D.; Rohr, Jason R.

    2016-01-01

    ABSTRACT Sewage spills can release antibiotic-resistant bacteria into surface waters, contributing to environmental reservoirs and potentially impacting human health. Vancomycin-resistant enterococci (VRE) are nosocomial pathogens that have been detected in environmental habitats, including soil, water, and beach sands, as well as wildlife feces. However, VRE harboring vanA genes that confer high-level resistance have infrequently been found outside clinical settings in the United States. This study found culturable Enterococcus faecium harboring the vanA gene in water and sediment for up to 3 days after a sewage spill, and the quantitative PCR (qPCR) signal for vanA persisted for an additional week. Culturable levels of enterococci in water exceeded recreational water guidelines for 2 weeks following the spill, declining about five orders of magnitude in sediments and two orders of magnitude in the water column over 6 weeks. Analysis of bacterial taxa via 16S rRNA gene sequencing showed changes in community structure through time following the sewage spill in sediment and water. The spread of opportunistic pathogens harboring high-level vancomycin resistance genes beyond hospitals and into the broader community and associated habitats is a potential threat to public health, requiring further studies that examine the persistence, occurrence, and survival of VRE in different environmental matrices. IMPORTANCE Vancomycin-resistant enterococci (VRE) are harmful bacteria that are resistant to the powerful antibiotic vancomycin, which is used as a last resort against many infections. This study followed the release of VRE in a major sewage spill and their persistence over time. Such events can act as a means of spreading vancomycin-resistant bacteria in the environment, which can eventually impact human health. PMID:27422829

  3. 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.

  4. Water Quality in Surface Water: A Preliminary Assessment of Heavy Metal Contamination of the Mashavera River, Georgia

    PubMed Central

    Urushadze, Teo

    2018-01-01

    Water quality contamination by heavy metal pollution has severe effects on public health. In the Mashavera River Basin, an important agricultural area for the national food system in Georgia (e.g., vegetable, dairy and wine production), water contamination has multiple influences on the regional and country-wide health. With new industrial activities in the region, sediment extraction, and discharge of untreated wastewater into the river, its tributaries and irrigation canals, a comprehensive study of water quality was greatly needed. This study examined sediment and water samples from 17 sampling sites in the Mashavera River Basin during the high and low precipitation seasons. The results were characterized utilizing the Geo-accumulation Index (Igeo), Enrichment Factor (EF), Pollution Load index (PLI), Contamination Factor (CF) and Metal Index (MI). According to the CFs, Cu > Cd > Zn > Pb > Fe > Mn > Ni > Cr > Hg is the descending order for the content of all observed heavy metals in sediments collected in both seasons. Fe and As were additionally examined in water samples. Overall, As, Cd and Pb, all highly toxic elements, were found in high concentrations in downstream sample sites. According to these results, comprehensive monitoring with narrow intervals between sampling dates, more sample sites along all waterways, and proximate observation of multiple trace metal elements are highly recommended. Moreover, as the part of the water quality governance system, an immediate and sustainable collective action by all stakeholders to control the pollution level is highly recommended, as this issue is linked to the security of the national food system and poses a local public health risk. PMID:29597320

  5. Water monitoring by optofluidic Raman spectroscopy for in situ applications.

    PubMed

    Persichetti, Gianluca; Bernini, Romeo

    2016-08-01

    The feasibility of water monitoring by Raman spectroscopy with a portable optofluidic system for in-situ applications has been successfully demonstrated. In the proposed approach, the sample under analysis is injected into a capillary nozzle in order to produce a liquid jet that acts as an optical waveguide. This jet waveguide provides an effective strategy to excite and collect the Raman signals arising from water contaminants due to the high refractive index difference between air and water. The proposed approach avoids any necessity of liquid container or flow cell and removes any background signal coming from the sample container commonly affects Raman measurements. Furthermore, this absence is a significant advantage for in situ measurements where fouling problems can be relevant and cleaning procedures are troublesome. The extreme simplicity and efficiency of the optical scheme adopted in our approach result in highly sensitive and rapid measurements that have been performed on different representative water pollutants. The experimental results demonstrate the high potentiality of our device in water quality monitoring and analysis. In particular, nitrate and sulfate are detected below the maximum contamination level allowed for drinking water, whereas a limit of detection of 40mg/l has been found for benzene. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. High concentrations of fluoride and boron in drinking water wells in the Muenster region--results of a preliminary investigation.

    PubMed

    Queste, A; Lacombe, M; Hellmeier, W; Hillermann, F; Bortulussi, B; Kaup, M; Ott, K; Mathys, W

    2001-03-01

    In 1998, two cases of severe dental fluorosis in schoolchildren occurred in the Muenster region. These cases took place in one household, where fluoridated toothpaste, fluoridated salt, and fluoride tablets were consumed. Furthermore, the family used drinking water from its private well only. Analyses of the well water ordered by local health officials revealed very high amounts of fluoride, boron, and other electrolytes. This unusual combination of high amounts of fluoride and boron could also be found in the water of a great number of other private wells that are the only source for drinking water in this rural region of the Muensterland. Anthropogenic sources could be excluded. Because of this, the results of the water samples were collated to the specific geological situation in this area. In the Muenster region there are marl layers of the chalk era covered with quarternary sediments. The quarternary sediments are up to 10 to 20 metres thick and they usually conduct the groundwater. The marl contains high concentrations of fluoride and boron. In some places the groundwater has contact with these layers. To check the amount of fluoride and boron in the groundwater, indicator values were sought, which can give a hint of high contents of these trace elements. In this study the conductivity and acidity were identified as possible indicators of a high amount of fluoride and boron in the drinking water in this specific region. To work economically and efficiently, the drinking water should be checked for fluoride and boron on a regular basis only when these values are extraordinarily high. In the case of high concentrations, especially of fluoride, in the drinking water the persons concerned should be informed about their potential health risk, giving them the opportunity to optimise the total daily intake of fluoride.

  7. Linking hyporheic flow and nitrogen cycling near the Willamette River - A large river in Oregon, USA

    USGS Publications Warehouse

    Hinkle, S.R.; Duff, J.H.; Triska, F.J.; Laenen, A.; Gates, E.B.; Bencala, K.E.; Wentz, D.A.; Silva, S.R.

    2001-01-01

    Several approaches were used to characterize ground water/surface water interactions near the Willamette River - A large (ninth order) river in Oregon, USA. A series of potentiometric surface maps demonstrated the presence of highly dynamic hydraulic gradients between rivers and the adjacent aquifer. Hyporheic zone gradients extended on the order of hundreds of meters. River gains and losses at the river stretch scale (tens of kilometers) were consistent with fluxes implied by the potentiometric surface maps, and apparently reflect regional ground water/surface water interactions. Gains and losses of up to 5-10% of streamflow were observed at this scale. On the river reach scale (1-2 km), gains and losses on the order of 5% of streamflow were interpreted as representing primarily local hyporheic exchange. Isotopic and chemical data collected from shallow hyporheic zone wells demonstrated interaction between regional ground water and river water. The origin of sampled hyporheic zone water ranged from a mixture dominated by regional ground water to water containing 100% river water. The common assumption that ground and river water mix primarily in the river channel is not applicable in this system. Isotopic and chemical data also indicated that significant (nearly complete) vegetative nitrate uptake and/or nitrate reduction occurred in water from 4 of 12 hyporheic zone sites. In these cases, it was primarily nitrate transported to the hyporheic zone in regional ground water that was removed from solution. Isotopes of water and nitrate indicated that hyporheic zone water sampled at two sites was composed of water originating as river water and demonstrated that significant vegetative nitrate uptake and nitrate reduction occurred along these hyporheic zone flowpaths. Thus, the hyporheic zone may, in some instances, serve to remove nitrate from river water. Additional investigations with chemical tools and microbial enzyme assays were conducted at one hyporheic site. A strong vertical redox gradient was observed, with nitrate-limited denitrification potential in deeper sediment and both nitrification and denitrification potential in shallower sediment. Since nitrogen cycling is strongly affected by redox conditions, nitrogen cycling in the hyporheic zone of this large-river system likely is affected by dynamics of ground water/surface water interactions that control fluxes of nitrogen and other redox species to hyporheic zone sediment.

  8. Cellulose Nanomaterials in Water Treatment Technologies

    PubMed Central

    Carpenter, Alexis Wells; de Lannoy, Charles François; Wiesner, Mark R.

    2015-01-01

    Cellulose nanomaterials are naturally occurring with unique structural, mechanical and optical properties. While the paper and packaging, automotive, personal care, construction, and textiles industries have recognized cellulose nanomaterials’ potential, we suggest cellulose nanomaterials have great untapped potential in water treatment technologies. In this review, we gather evidence of cellulose nanomaterials’ beneficial role in environmental remediation and membranes for water filtration, including their high surface area-to-volume ratio, low environmental impact, high strength, functionalizability, and sustainability. We make direct comparison between cellulose nanomaterials and carbon nanotubes (CNTs) in terms of physical and chemical properties, production costs, use and disposal in order to show the potential of cellulose nanomaterials as a sustainable replacement for CNTs in water treatment technologies. Finally, we comment on the need for improved communication and collaboration across the myriad industries invested in cellulose nanomaterials production and development to achieve an efficient means to commercialization. PMID:25837659

  9. 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.

  10. Ion chromatographic determination of lithium at trace level concentrations. Application to a tracer experiment in a high-mountain lake.

    PubMed

    Nickus, U; Thies, H

    2001-06-22

    The water residence time of a high-mountain seepage lake in the Austrian Alps was derived from the flushing rate of a tracer substance. A diluted lithium chloride solution was injected into the lake during holomictic conditions in order to favour the homogeneous distribution of the tracer. The exponential decline of the mass of lithium in the lake revealed a water residence time of 1.5 to 3 months for summer and almost no lake water exchange during winter. Lithium concentrations ranged from background values of 0.06 microg l(-1) to about 3 microg l(-1) immediately after the tracer injection. Lake water samples were analyzed with ion-exchange chromatography using a Dionex device with a CS 12A separation column. The method detection limit determined according to the definition of the US Envirinmental Protection Agency amounted to 0.009 microg l(-1).

  11. Evaluation of membrane bioreactor for advanced treatment of industrial wastewater and reverse osmosis pretreatment

    PubMed Central

    2013-01-01

    The evaluation of a membrane bioreactor (MBR) for pretreatment of reverse osmosis (RO) in order to reuse and reclamation of industrial town wastewater treatment plant was investigated in this study. Performance of MBR effluent through water quality in term of parameters such as chemical oxygen demand (COD), total suspended solids (TSS), total nitrogen (TN) and total coliform (TC) were measured. Also Silt density index (SDI) was used as indicator for RO feed water. The results of this study demonstrated that MBR produce a high quality permeate water. Approximately 75%, 98%, 74% and 99.9% removal of COD, TSS, TN and TC were recorded, respectively. Also SDI of the permeate effluent from membrane was below 3 for most of the times. It means that pilot yield a high quality treated effluent from the membrane module which can be used as RO feed water. PMID:24355199

  12. Cellulose nanomaterials in water treatment technologies.

    PubMed

    Carpenter, Alexis Wells; de Lannoy, Charles-François; Wiesner, Mark R

    2015-05-05

    Cellulose nanomaterials are naturally occurring with unique structural, mechanical and optical properties. While the paper and packaging, automotive, personal care, construction, and textiles industries have recognized cellulose nanomaterials' potential, we suggest cellulose nanomaterials have great untapped potential in water treatment technologies. In this review, we gather evidence of cellulose nanomaterials' beneficial role in environmental remediation and membranes for water filtration, including their high surface area-to-volume ratio, low environmental impact, high strength, functionalizability, and sustainability. We make direct comparison between cellulose nanomaterials and carbon nanotubes (CNTs) in terms of physical and chemical properties, production costs, use and disposal in order to show the potential of cellulose nanomaterials as a sustainable replacement for CNTs in water treatment technologies. Finally, we comment on the need for improved communication and collaboration across the myriad industries invested in cellulose nanomaterials production and development to achieve an efficient means to commercialization.

  13. The Evaluation and Implementation of a Water Containment System to Support Aerospace Flywheel Testing

    NASA Technical Reports Server (NTRS)

    Trase, Larry M.

    2002-01-01

    High-energy flywheel systems for aerospace power storage and attitude control applications are being developed because of the potential for increasing the energy density and reducing operational costs. A significant challenge facing the development of the test hardware is containment of the rotating elements in the event of a failure during the development and qualification stages of testing. This containment is critical in order to ensure the safety of the test personnel and the facility. A containment system utilizing water as the containment media is presented. Water containment was found to be a low cost, flexible, and highly effective containment system. Ballistic test results and analytical results are discussed along with a description of a flywheel test facility that was designed and built utilizing the water containment system at the NASA Glenn Research Center at Lewis Field in Cleveland, Ohio.

  14. Water quality and agricultural practices: the case study of southern Massaciuccoli reclaimed land (Tuscany, Italy)

    NASA Astrophysics Data System (ADS)

    Pistocchi, Chiara; Baneschi, Ilaria; Basile, Paolo; Cannavò, Silvia; Guidi, Massimo; Risaliti, Rosalba; Rossetto, Rudy; Sabbatini, Tiziana; Silvestri, Nicola; Bonari, Enrico

    2010-05-01

    Owing to increasing anthropogenic impacts, lagoons and wetlands are being exposed to environmental degradation. Therefore, the sustainable management of these environmental resources is a fundamental issue to maintain either the ecosystems and the human activity. The Massaciuccoli Lake is a coastal lake of fresh to brackish water surrounded by a marsh, which drains a total catchment of about 114 km2. Large part of the basin has been reclaimed since 1930 by means of pumping stations forcing water from the drained areas into the lake. The system is characterized by: high complexity of the hydrological setting; subsidence of the peaty soils in the reclaimed area (2 to 3 m in 70 years), that left the lake perched; reclaimed land currently devoted mainly to conventional agriculture (e.g.: maize monoculture) along with some industrial sites, two sewage treatment plants and some relevant urban settlements; social conflicts among different land users because of the impact on water quality and quantity. The interaction between such a fragile natural system and human activities leads to an altered ecological status mainly due to eutrophication and water salinisation. Hence, the present work aims at identifying and assessing the sources of nutrients (phosphorous in particular) into the lake, and characterising land use and some socio-economic aspects focusing on agricultural systems, in order to set up suitable mitigation measures. Water quantity and quality in the most intensively cultivated sub-catchment, placed 0.5 to 3 m under m.s.l. were monitored in order to underlain the interaction between water and its nutrient load. Questionnaires and interviews to farmers were conducted to obtain information about agricultural practices, farm management, risks and constraints for farming activities. The available information about the natural system and land use were collected and organised in a GIS system: a conceptual model of surface water hydrodinamics was build up and 14 sampling points were monitored monthly during 2008-2009. The main water physical and chemical parameters, including nutrients, as well as the principal soil types within the sub-catchment were analysed. First results point out: the reclaimed land presents a dense drainage network hydraulically interconnected with the shallow aquifer; surface waters present a high chemical heterogeneity: three main hydrochemical facies were identified and compared with nutrients contents and soil chemistry; artificially induced recharge to the reclaimed land aquifer occurs by means of lake water infiltration. This forces the pumping stations to remove an additional amount of water in order to allow land cultivation; the water salinity in the drainage network may increase during summer period. This could be related both to irrigation using lake water and a further contribution due to evapotranspiration processes; agricultural land use changed during the last 15 years, and shifted to less intensive farming practices. Fertilization levels dropped from 200 and 150 to 100 and 50 kg/ha N and P2O5 respectively, and the irrigated area decreased from 50% to 40% of the total utilised agricultural area; in the low land peaty area, the higher content of sulphate and phosphate in the drainage water supports the hypothesis that peat degradation could be a relevant source of nutrients. As a result, the impact of fertilizer use on the water quality is limited, while land management (e.g. water use and land reclamation) constitutes the key issue. Therefore, local stakeholders participation, farmers above all, should be supported in future management and planning actions in order to adapt socio-economic needs with the peculiar biophysical conditions.

  15. Crew Exploration Vehicle (CEV) Water Landing Simulation

    NASA Technical Reports Server (NTRS)

    Littell, Justin D.; Lawrence, Charles; Carney, Kelly S.

    2007-01-01

    Crew Exploration Vehicle (CEV) water splashdowns were simulated in order to find maximum acceleration loads on the astronauts and spacecraft under various landing conditions. The acceleration loads were used in a Dynamic Risk Index (DRI) program to find the potential risk for injury posed on the astronauts for a range of landing conditions. The DRI results showed that greater risks for injury occurred for two landing conditions; when the vertical velocity was large and the contact angle between the spacecraft and the water impact surface was zero, and when the spacecraft was in a toe down configuration and both the vertical and horizontal landing velocities were large. Rollover was also predicted to occur for cases where there is high horizontal velocity and low contact angles in a toe up configuration, and cases where there was a high horizontal velocity with high contact angles in a toe down configuration.

  16. Natural solar photolysis of total organic chlorine, bromine and iodine in water.

    PubMed

    Abusallout, Ibrahim; Hua, Guanghui

    2016-04-01

    Municipal wastewater has been increasingly used to augment drinking water supplies due to the growing water scarcity. Wastewater-derived disinfection byproducts (DBPs) may negatively affect the aquatic ecosystems and human health of downstream communities during water reuse. The objective of this research was to determine the degradation kinetics of total organic chlorine (TOCl), bromine (TOBr) and iodine (TOI) in water by natural sunlight irradiation. Outdoor solar photolysis experiments were performed to investigate photolytic degradation of the total organic halogen (TOX) formed by fulvic acid and real water and wastewater samples. The results showed that TOX degradation by sunlight irradiation followed the first-order kinetics with half-lives in the range of 2.6-10.7 h for different TOX compounds produced by fulvic acid. The TOX degradation rates were generally in the order of TOI > TOBr ≅ TOCl(NH2Cl) > TOCl(Cl2). High molecular weight TOX was more susceptible to solar photolysis than corresponding low molecular weight halogenated compounds. The nitrate and sulfite induced indirect TOX photolysis rates were less than 50% of the direct photolysis rates under the conditions of this study. Fulvic acid and turbidity in water reduced TOX photodegradation. These results contribute to a better understanding of the fate of chlorinated, brominated and iodinated DBPs in surface waters. Published by Elsevier Ltd.

  17. Ambient noise imaging in warm shallow waters; robust statistical algorithms and range estimation.

    PubMed

    Chitre, Mandar; Kuselan, Subash; Pallayil, Venugopalan

    2012-08-01

    The high frequency ambient noise in warm shallow waters is dominated by snapping shrimp. The loud snapping noises they produce are impulsive and broadband. As the noise propagates through the water, it interacts with the seabed, sea surface, and submerged objects. An array of acoustic pressure sensors can produce images of the submerged objects using this noise as the source of acoustic "illumination." This concept is called ambient noise imaging (ANI) and was demonstrated using ADONIS, an ANI camera developed at the Scripps Institution of Oceanography. To overcome some of the limitations of ADONIS, a second generation ANI camera (ROMANIS) was developed at the National University of Singapore. The acoustic time series recordings made by ROMANIS during field experiments in Singapore show that the ambient noise is well modeled by a symmetric α-stable (SαS) distribution. As high-order moments of SαS distributions generally do not converge, ANI algorithms based on low-order moments and fractiles are developed and demonstrated. By localizing nearby snaps and identifying the echoes from an object, the range to the object can be passively estimated. This technique is also demonstrated using the data collected with ROMANIS.

  18. Ultra-high resolution water window x ray microscope optics design and analysis

    NASA Technical Reports Server (NTRS)

    Shealy, David L.; Wang, C.

    1993-01-01

    This project has been focused on the design and analysis of an ultra-high resolution water window soft-x-ray microscope. These activities have been accomplished by completing two tasks contained in the statement of work of this contract. The new results from this work confirm: (1) that in order to achieve resolutions greater than three times the wavelength of the incident radiation, it will be necessary to use spherical mirror surfaces and to use graded multilayer coatings on the secondary in order to accommodate the large variations of the angle of incidence over the secondary when operating the microscope at numerical apertures of 0.35 or greater; (2) that surface contour errors will have a significant effect on the optical performance of the microscope and must be controlled to a peak-to-valley variation of 50-100 A and a frequency of 8 periods over the surface of a mirror; and (3) that tolerance analysis of the spherical Schwarzschild microscope has been shown that the water window operations will require 2-3 times tighter tolerances to achieve a similar performance of operations with 130 A radiation. These results have been included in a manuscript included in the appendix.

  19. Solution-Based Electro-Orientation Spectroscopy (EOS) for Contactless Measurement of Semiconductor Nanowires

    NASA Astrophysics Data System (ADS)

    Yuan, Wuhan; Mohabir, Amar; Tutuncuoglu, Gozde; Filler, Michael; Feldman, Leonard; Shan, Jerry

    2017-11-01

    Solution-based, contactless methods for determining the electrical conductivity of nanowires and nanotubes have unique advantages over conventional techniques in terms of high throughput and compatibility with further solution-based processing and assembly methods. Here, we describe the solution-based electro-orientation spectroscopy (EOS) method, in which nanowire conductivity is measured from the AC-electric-field-induced alignment rate of the nanowire in a suspending fluid. The particle conductivity is determined from the measured crossover frequency between conductivity-dominated, low-frequency alignment to the permittivity-dominated, high-frequency regime. We discuss the extension of the EOS measurement range by an order-of-magnitude, taking advantage of the high dielectric constant of deionized water. With water and other fluids, we demonstrate that EOS can quantitatively characterize the electrical conductivities of nanowires over a 7-order-of-magnitude range, 10-5 to 102 S/m. We highlight the efficiency and utility of EOS for nanomaterial characterization by statistically characterizing the variability of semiconductor nanowires of the same nominal composition, and studying the connection between synthesis parameters and properties. NSF CBET-1604931.

  20. Electrolysis Propulsion Provides High-Performance, Inexpensive, Clean Spacecraft Propulsion

    NASA Technical Reports Server (NTRS)

    deGroot, Wim A.

    1999-01-01

    An electrolysis propulsion system consumes electrical energy to decompose water into hydrogen and oxygen. These gases are stored in separate tanks and used when needed in gaseous bipropellant thrusters for spacecraft propulsion. The propellant and combustion products are clean and nontoxic. As a result, costs associated with testing, handling, and launching can be an order of magnitude lower than for conventional propulsion systems, making electrolysis a cost-effective alternative to state-of-the-art systems. The electrical conversion efficiency is high (>85 percent), and maximum thrust-to-power ratios of 0.2 newtons per kilowatt (N/kW), a 370-sec specific impulse, can be obtained. A further advantage of the water rocket is its dual-mode potential. For relatively high thrust applications, the system can be used as a bipropellant engine. For low thrust levels and/or small impulse bit requirements, cold gas oxygen can be used alone. An added innovation is that the same hardware, with modest modifications, can be converted into an energy-storage and power-generation fuel cell, reducing the spacecraft power and propulsion system weight by an order of magnitude.

  1. Controls on Water Use for Thermoelectric Generation: Case Study Texas, U.S.

    PubMed Central

    2013-01-01

    Large-scale U.S. dependence on thermoelectric (steam electric) generation requiring water for cooling underscores the need to understand controls on this water use. The study objective was to quantify water consumption and withdrawal for thermoelectric generation, identifying controls, using Texas as a case study. Water consumption for thermoelectricity in Texas in 2010 totaled ∼0.43 million acre feet (maf; 0.53 km3), accounting for ∼4% of total state water consumption. High water withdrawals (26.2 maf, 32.3 km3) mostly reflect circulation between ponds and power plants, with only two-thirds of this water required for cooling. Controls on water consumption include (1) generator technology/thermal efficiency and (2) cooling system, resulting in statewide consumption intensity for natural gas combined cycle generators with mostly cooling towers (0.19 gal/kWh) being 63% lower than that of traditional coal, nuclear, or natural gas steam turbine generators with mostly cooling ponds (0.52 gal/kWh). The primary control on water withdrawals is cooling system, with ∼2 orders of magnitude lower withdrawals for cooling towers relative to once-through ponds statewide. Increases in natural gas combined cycle plants with cooling towers in response to high production of low-cost natural gas has greatly reduced water demand for thermoelectric cooling since 2000. PMID:23937226

  2. Controls on water use for thermoelectric generation: case study Texas, US.

    PubMed

    Scanlon, Bridget R; Reedy, Robert C; Duncan, Ian; Mullican, William F; Young, Michael

    2013-10-01

    Large-scale U.S. dependence on thermoelectric (steam electric) generation requiring water for cooling underscores the need to understand controls on this water use. The study objective was to quantify water consumption and withdrawal for thermoelectric generation, identifying controls, using Texas as a case study. Water consumption for thermoelectricity in Texas in 2010 totaled ∼0.43 million acre feet (maf; 0.53 km(3)), accounting for ∼4% of total state water consumption. High water withdrawals (26.2 maf, 32.3 km(3)) mostly reflect circulation between ponds and power plants, with only two-thirds of this water required for cooling. Controls on water consumption include (1) generator technology/thermal efficiency and (2) cooling system, resulting in statewide consumption intensity for natural gas combined cycle generators with mostly cooling towers (0.19 gal/kWh) being 63% lower than that of traditional coal, nuclear, or natural gas steam turbine generators with mostly cooling ponds (0.52 gal/kWh). The primary control on water withdrawals is cooling system, with ∼2 orders of magnitude lower withdrawals for cooling towers relative to once-through ponds statewide. Increases in natural gas combined cycle plants with cooling towers in response to high production of low-cost natural gas has greatly reduced water demand for thermoelectric cooling since 2000.

  3. Near- and Extended-Edge X-Ray-Absorption Fine-Structure Spectroscopy Using Ultrafast Coherent High-Order Harmonic Supercontinua

    NASA Astrophysics Data System (ADS)

    Popmintchev, Dimitar; Galloway, Benjamin R.; Chen, Ming-Chang; Dollar, Franklin; Mancuso, Christopher A.; Hankla, Amelia; Miaja-Avila, Luis; O'Neil, Galen; Shaw, Justin M.; Fan, Guangyu; Ališauskas, Skirmantas; Andriukaitis, Giedrius; Balčiunas, Tadas; Mücke, Oliver D.; Pugzlys, Audrius; Baltuška, Andrius; Kapteyn, Henry C.; Popmintchev, Tenio; Murnane, Margaret M.

    2018-03-01

    Recent advances in high-order harmonic generation have made it possible to use a tabletop-scale setup to produce spatially and temporally coherent beams of light with bandwidth spanning 12 octaves, from the ultraviolet up to x-ray photon energies >1.6 keV . Here we demonstrate the use of this light for x-ray-absorption spectroscopy at the K - and L -absorption edges of solids at photon energies near 1 keV. We also report x-ray-absorption spectroscopy in the water window spectral region (284-543 eV) using a high flux high-order harmonic generation x-ray supercontinuum with 109 photons/s in 1% bandwidth, 3 orders of magnitude larger than has previously been possible using tabletop sources. Since this x-ray radiation emerges as a single attosecond-to-femtosecond pulse with peak brightness exceeding 1026 photons/s /mrad2/mm2/1 % bandwidth, these novel coherent x-ray sources are ideal for probing the fastest molecular and materials processes on femtosecond-to-attosecond time scales and picometer length scales.

  4. Assesment of pesticide fluxes to surface water using Uranine in Colombia

    NASA Astrophysics Data System (ADS)

    Garcia-Santos, G.; Scheiben, D.; Diaz, J.; Leuenberger, F.; Binder, C. R.

    2009-04-01

    In the highlands of Colombia, potato farmers maximize their yields by the application of pesticides. Properly applied pesticides can significantly reduce yield loss and improve product quality; however their misuse leads to human health and environmental problems, i.e. water bodies contaminated with pesticides. Due to the lack of control regarding local pesticide use, unmeasured hydrological parameters and use of local water runoff as a drinking water supply, an assessment of the impact of agricultural practice on water quality is mandatory as first stage. In order to accomplish this, our study assesses pesticide fluxes to surface water using the tracer Uranine. The experimental area La Hoya main basin (3 km2) contains the Pantano Verde river which flows into the Teatinos river in the Boyaca region (Colombia). Some facts such as the deep soils in the area and the importance of the unsaturated zone for the sorption and degradation of pesticides suggest a lack of contaminants in groundwater. However, due to the humid conditions, steep slopes and an intensive agricultural with high pesticide use, we expect surface water to be highly contaminated. In order to assess pesticide pathways, a tracer (Uranine), detectable at very low amount was used. Four local farmers applied the tracer instead of the pesticide mixture covering a total surface of 1.2 10-2 km2. Meteorological data were measured every 15 min with one compact meteorological station installed within the basin and water flow and water sampling were obtained using an ISCO-6700 water sampler, during one week every 10 min in the outlet of Pantano Verde River. In addition, three pairs of membranes were installed down the river and collected 1 week, one month and 4 months after the experiment to measure tracer accumulation. The tracer in water was analysed using a fluorescent spectrometer. Results of this study show first variations of tracer concentration in water in La Hoya basin and constitute an initial steep in assessing the impact of agricultural practices in the local water quality under the influence of pesticides.

  5. Gaseous fuel production from nonrecyclable paper wastes by using supported metal catalysts in high-temperature liquid water.

    PubMed

    Yamaguchi, Aritomo; Hiyoshi, Norihito; Sato, Osamu; Bando, Kyoko K; Shirai, Masayuki

    2010-06-21

    Paper wastes are used for the production of gaseous fuels over supported metal catalysts. The gasification of the nonrecyclable paper wastes, such as shredded documents and paper sludge, is carried out in high-temperature liquid water. The order of the catalytic activity for the gasification is found to be ruthenium>rhodium>platinum>palladium. A charcoal-supported ruthenium catalyst (Ru/C) is the most effective for the gasification of paper and cellulose. Paper wastes are gasified to a limited degree (32.6 carbon %) for 30 min in water at 523 K to produce methane and carbon dioxide, with a small amount of hydrogen. At 573 K, more complete gasification with almost 100 carbon % is achieved within 10 min in water. At 523 K, the gas yield of paper gasification over Ru/C is higher than that of cellulose powder. The gas yields are increased by ball-milling treatment of the recycled paper and cellulose powder. Printed paper wastes are also gasified at 523 K in water.

  6. LCA of greywater management within a water circular economy restorative thinking framework.

    PubMed

    Dominguez, Sara; Laso, Jara; Margallo, María; Aldaco, Rubén; Rivero, Maria J; Irabien, Ángel; Ortiz, Inmaculada

    2018-04-15

    Greywater reuse is an attractive option for the sustainable management of water under water scarcity circumstances, within a water circular economy restorative thinking framework. Its successful deployment relies on the availability of low cost and environmentally friendly technologies. The life cycle assessment (LCA) approach provides the appropriate methodological tool for the evaluation of alternative treatments based on environmental decision criteria and, therefore, it is highly useful during the process conceptual design. This methodology should be employed in the early design phase to select those technologies with lower environmental impact. This work reports the comparative LCA of three scenarios for greywater reuse: photocatalysis, photovoltaic solar-driven photocatalysis and membrane biological reactor, in order to help the selection of the most environmentally friendly technology. The study has been focused on the removal of the surfactant sodium dodecylbenzenesulfonate, which is used in the formulation of detergents and personal care products and, thus, widely present in greywater. LCA was applied using the Environmental Sustainability Assessment methodology to obtain two main environmental indicators in order to simplify the decision making process: natural resources and environmental burdens. Energy consumption is the main contributor to both indicators owing to the high energy consumption of the light source for the photocatalytic greywater treatment. In order to reduce its environmental burdens, the most desirable scenario would be the use of solar light for the photocatalytic transformation. However, while the technological challenge of direct use of solar light is approached, the environmental suitability of the photovoltaic solar energy driven photocatalysis technology to greywater reuse has been demonstrated, as it involves the smallest environmental impact among the three studied alternatives. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Evaluating the role of higher order nonlinearity in water of finite and shallow depth with a direct numerical simulation method of Euler equations

    NASA Astrophysics Data System (ADS)

    Fernandez, L.; Toffoli, A.; Monbaliu, J.

    2012-04-01

    In deep water, the dynamics of surface gravity waves is dominated by the instability of wave packets to side band perturbations. This mechanism, which is a nonlinear third order in wave steepness effect, can lead to a particularly strong focusing of wave energy, which in turn results in the formation of waves of very large amplitude also known as freak or rogue waves [1]. In finite water depth, however, the interaction between waves and the ocean floor induces a mean current. This subtracts energy from wave instability and causes it to cease for relative water depth , where k is the wavenumber and h the water depth [2]. Yet, this contradicts field observations of extreme waves such as the infamous 26-m "New Year" wave that have mainly been recorded in regions of relatively shallow water . In this respect, recent studies [3] seem to suggest that higher order nonlinearity in water of finite depth may sustain instability. In order to assess the role of higher order nonlinearity in water of finite and shallow depth, here we use a Higher Order Spectral Method [4] to simulate the evolution of surface gravity waves according to the Euler equations of motion. This method is based on an expansion of the vertical velocity about the surface elevation under the assumption of weak nonlinearity and has a great advantage of allowing the activation or deactivation of different orders of nonlinearity. The model is constructed to deal with an arbitrary order of nonlinearity and water depths so that finite and shallow water regimes can be analyzed. Several wave configurations are considered with oblique and collinear with the primary waves disturbances and different water depths. The analysis confirms that nonlinearity higher than third order play a substantial role in the destabilization of a primary wave train and subsequent growth of side band perturbations.

  8. Microalgae removal with Moringa oleifera.

    PubMed

    Barrado-Moreno, M M; Beltran-Heredia, J; Martín-Gallardo, J

    2016-02-01

    Moringa oleifera seed extract was tested for algae (Chlorella, Microcystis, Oocystis and Scenedesmus) removal by Jar-test technique. This coagulant can be used in drinking water treatment. Jar-test has been carried out in order to evaluate the efficiency of this natural coagulant agent inside real surface water matrix. The influence of variables has been studied in this process, including operating parameters such as coagulant dosage, initial algae concentration, pH, agitation time and water matrix. Removal capacity is verified for water with high contamination of algae while the process is not affected by the pH and water matrix. Coagulation process may be modelling through Langmuir and Freundlich adsorption hypothesis, so acceptable r2 coefficients are obtained. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Failing our children: lead in U.S. school drinking water.

    PubMed

    Lambrinidou, Yanna; Triantafyllidou, Simoni; Edwards, Marc

    2010-01-01

    Lead is the most prevalent toxicant in U. S. school drinking water. Yet for the vast majority of schools, federal regulation for testing taps and remediating contamination is voluntary. Using school case studies, this article discusses the regulatory vacuum that leaves children unprotected from potential exposure to very high lead doses through consumption of school water. Controlling lead hazards from water fountains, coolers, and other drinking water outlets in schools requires improved sampling protocols that can capture the inherent variability of lead release from plumbing and measure both the particulate and dissolved lead present in water. There is a need to reevaluate the potential public health implications of lead-contaminated drinking water in schools. Accounting for this misunderstood and largely overlooked exposure source is necessary in order to better understand and address childhood lead poisoning in the U. S.

  10. Design highwater clearances for highway pavements appendix : volume II, appendix, August 2008.

    DOT National Transportation Integrated Search

    2008-08-01

    High groundwater table exerts detrimental effects on the roadway base and the whole pavement. Base clearance guidelines have been developed to prevent water from entering the pavement system in order to reduce its detrimental effects. In these guidel...

  11. Design highwater clearances for highway pavements : volume I, final report, August 2008.

    DOT National Transportation Integrated Search

    2008-08-01

    High groundwater table exerts detrimental effects on the roadway base and the whole pavement. Base : clearance guidelines have been developed to prevent water from entering the pavement system in order to : reduce its detrimental effects. In these gu...

  12. A Survey of Recreation Behavior and Attitude Patterns of High School Juniors and Seniors: Implications for Environmental Education and Resource Management.

    ERIC Educational Resources Information Center

    Ditton, Robert B.; Johnsen, Per K.

    In this study, the behavior and attitude patterns of high school juniors and seniors in northeastern Wisconsin have been examined with respect to recreational activities and water quality conditions. Most popular activities were identified in order as swimming, boating, fishing, waterskiing, sailing, and duck hunting. Location of participation in…

  13. Streamflow and nutrient dependence of temperature effects on dissolved oxygen in low-order forest streams

    Treesearch

    April Mason; Y. Jun Xu; Philip Saksa; Adrienne Viosca; Johnny M. Grace; John Beebe; Richard Stich

    2007-01-01

    Low dissolved oxygen (DO) concentrations in streams can be linked to both natural conditions and human activities. In Louisiana, natural stream conditions such as low flow, high temperature and high organic content, often result in DO levels already below current water quality criteria, making it difficult to develop standards for Best Management Practices (BMPs)....

  14. A discontinuous Galerkin method for the shallow water equations in spherical triangular coordinates

    NASA Astrophysics Data System (ADS)

    Läuter, Matthias; Giraldo, Francis X.; Handorf, Dörthe; Dethloff, Klaus

    2008-12-01

    A global model of the atmosphere is presented governed by the shallow water equations and discretized by a Runge-Kutta discontinuous Galerkin method on an unstructured triangular grid. The shallow water equations on the sphere, a two-dimensional surface in R3, are locally represented in terms of spherical triangular coordinates, the appropriate local coordinate mappings on triangles. On every triangular grid element, this leads to a two-dimensional representation of tangential momentum and therefore only two discrete momentum equations. The discontinuous Galerkin method consists of an integral formulation which requires both area (elements) and line (element faces) integrals. Here, we use a Rusanov numerical flux to resolve the discontinuous fluxes at the element faces. A strong stability-preserving third-order Runge-Kutta method is applied for the time discretization. The polynomial space of order k on each curved triangle of the grid is characterized by a Lagrange basis and requires high-order quadature rules for the integration over elements and element faces. For the presented method no mass matrix inversion is necessary, except in a preprocessing step. The validation of the atmospheric model has been done considering standard tests from Williamson et al. [D.L. Williamson, J.B. Drake, J.J. Hack, R. Jakob, P.N. Swarztrauber, A standard test set for numerical approximations to the shallow water equations in spherical geometry, J. Comput. Phys. 102 (1992) 211-224], unsteady analytical solutions of the nonlinear shallow water equations and a barotropic instability caused by an initial perturbation of a jet stream. A convergence rate of O(Δx) was observed in the model experiments. Furthermore, a numerical experiment is presented, for which the third-order time-integration method limits the model error. Thus, the time step Δt is restricted by both the CFL-condition and accuracy demands. Conservation of mass was shown up to machine precision and energy conservation converges for both increasing grid resolution and increasing polynomial order k.

  15. Distributed modelling of water resources in the Lower Jordan River Basin - from present day variability to suitability for new water sources

    NASA Astrophysics Data System (ADS)

    Gunkel, Anne; Lange, Jens

    2010-05-01

    The Middle East is characterized by a high temporal and spatial variability of rainfall. As a result, water resources are not reliable and severe drought events are frequent, worsening the natural water scarcity. Single high magnitude events may dominate the water balance of entire seasons - a fact that is poorly represented in the assessments of available water resources that are normally based on long term averages. Therefore, a distributed hydrological model with a high temporal and spatial resolution is applied to the Lower Jordan River basin (LJRB). The focus is hereby to capture the variability of rainfall and to investigate how this signal is amplified in the hydrological cycle in this arid and semi arid environment. Rainfall variability is addressed through a volume scanning rainfall radar providing precipitation data with a resolution of 5 minutes for entire seasons that serves as input to a conceptual hydrological model. The raw radar data recorded by a C-Band system was pre-corrected by a multiple regression approach prior to regionalization to the LJRB, ground truthing with rainfall station data and conditional merging. Despite certain uncertainties, the data documents the accentuated rainfall variability in the entire LJRB. In order to include the full range of present rainfall variability, one average and two extreme seasons (wet and dry) are studied. Hydrological modelling is undertaken with a new modelling tool created by coupling two hydrological models, TRAIN and ZIN, complementing each other in respect to the addressed processes and water fluxes. The resulting modelling tool enables conceptual modelling of the processes relevant for semi-arid / arid environments with a high temporal and spatial resolution. The model is applied to the large scale LJRB (16,000 km²) in order to simulate all components of the water balance for three rainy seasons representing the present climate variability. Under given conditions of low data availability, the results give a basin wide view on the availability of surface water resources without human intervention with a high resolution in time (5 min) and space (up to 250 x 250 m²). The scarcity of water resources in many areas within the region is illustrated and detailed maps of the water balance components reveal spatial pattern of water availability characterizing the different potentials of regions or sub basins for water management options. Moreover, comparing different climate conditions provides valuable information for water management, including insights into the relation between green and blue water. For instance, runoff generation and percolation react stronger to changes in precipitation than evapotranspiration and the changes in runoff and percolation are considerably higher than the differences in rainfall between the three years. This amplification of rainfall variability by the hydrological cycle is significant for water management. Based on the results for current conditions, the impact of different scenarios and management options is analyzed, e.g. the effect of land use changes or the suitability of different regions for rainwater harvesting, one of the urgently needed new water sources.

  16. Fracture toughness, tensile and stress corrosion cracking properties of Alloy 600, Alloy 690 and their welds in water

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

    Brown, C.M.; Mills, W.J.

    1996-10-01

    The fracture toughness and tensile properties of Alloy 600, Alloy 690 and their welds, EN82H and EN52, were characterized in 54 and 338 C water with an elevated hydrogen content. Results were compared with air data to evaluate the effect of low and high temperature water on mechanical properties. In addition, the stress corrosion cracking (SCC) behavior of EN82H and EN52 welds was evaluated in 360 C water with high hydrogen. Elastic-plastic J{sub c} fracture toughness testing revealed that the fracture resistance of all test materials was exceptionally high in 54 and 338 C air and 338 C water, demonstratingmore » that fracture properties were essentially unaffected by the high temperature water environment. In 54 C water, however, J{sub c} values for EN82H and EN52 welds were reduced by an order of magnitude, and Alloy 690 showed a five-fold decrease in J{sub c}. Tensile properties for all test materials were essentially unaffected by the water environment, except for the total elongation for EN82H welds which was significantly reduced in 54 C water. At a strain rate of 5 x 10{sup 6} sec{sup {minus}1} in low temperature water, there appears to be sufficient time for environmental interactions to restrict ductility in EN82H welds. Constant-load testing of precracked weld specimens in 360 C water resulted in extensive intergranular SCC in EN82H welds loaded to K{sub I} levels between 35 and 55 MPa {radical}m, whereas no SCC occurred in EN52 welds under comparable test conditions.« less

  17. Boosting subsurface life: is subseafloor sediment a natural catalyst for radiolytic hydrogen production?

    NASA Astrophysics Data System (ADS)

    Sauvage, J.; Graham, D.; Spivack, A. J.; Dunlea, A. G.; Murray, R. W.; D'Hondt, S.

    2014-12-01

    Naturally occurring production of molecular hydrogen (H2) by water radiolysis may be a fundamentally important source of electron donors (energy) for life in subsurface environments where organic matter is scarce. Previous studies with very high gamma radiation rates and wet mineral phases have reported high H2 production relative to production from water radiolysis in the absence of solid phases. Numerical calculations by other previous studies have predicted enhanced H2 production from seawater radiolysis relative to pure water radiolysis, due to the interaction of anions with hydroxyl radicals. Given these reports, the potential catalytic influences of solid and dissolved chemical phases on radiolytic H2 production need to be carefully quantified in order to fully evaluate the role of radiolytic H2 as a microbial energy source. For such quantification, we undertook gamma-irradiation experiments with pure water, deep ocean water and mixtures (slurries, φ = 0.85) of seawater with: North Pacific abyssal clay and calcareous oozes, coastal sediment, zirconium dioxide, and zeolite. We carried out our experiments at the Rhode Island Nuclear Science Center using a 37Cesium source at low dose rates (up to 0.1 Gy/hr). Our results to date include the following. First, the per-dose radiolytic H2 yield of pure water at low dose rates is directly comparable to the per-dose yield at much higher dose rates (ca. 1 kGy/hr); this result indicates that H2 production rate is linearly related to radiation dose rate across four orders of magnitude. Second, there is no statistically significant difference (90% confidence limit) between the radiolytic H2 yield from pure water and that from seawater; this result rules out influence of abundant seawater salts on H2 yield from water radiolysis. Third, H2 production from a mixture of abyssal clay and seawater is 25% higher than the yield from pure water. This enhanced yield is consistent with catalysis of radiolytic H2 production by zeolite.

  18. Molecular dynamics shows that ion pairing and counterion anchoring control the properties of triflate micelles: a comparison with triflate at the air/water interface.

    PubMed

    Lima, Filipe S; Chaimovich, Hernan; Cuccovia, Iolanda M; Horinek, Dominik

    2014-02-11

    Micellar properties of dodecyltrimethylammonium triflate (DTA-triflate, DTATf) are very different from those of DTA-bromide (DTAB). DTATf aggregates show high aggregation numbers (Nagg), low degree of counterion dissociation (α), disk-like shape, high packing, ordering, and low hydration. These micellar properties and the low surface tension of NaTf aqueous solutions point to a high affinity of Tf(-) to the micellar and air/water interfaces. Although the micellar properties of DTATf are well defined, the source of the Tf(-) effect upon the DTA aggregates is unclear. Molecular dynamics (MD) simulations of Tf(-) (and Br(-)) at the air/water interface and as counterion of a DTA aggregate were performed to clarify the nature of Tf(-) preferences for these interfaces. The effect of NaTf or NaBr on surface tension calculated from MD simulations agreed with the reported experimental values. From the MD simulations a high affinity of Tf(-) toward the interface, which occurred in a specific orientation, was calculated. The micellar properties calculated from the MD simulations for DTATf and DTAB were consistent with experimental data: in MD simulations, the DTATf aggregate was more ordered, packed, and dehydrated than the DTAB aggregate. The Tf(-)/alkyltrimethylammonium interaction energies, calculated from the MD simulations, suggested ion pair formation at the micellar interface, stabilized by the preferential orientation of the adsorbed Tf(-) at the micellar interface.

  19. Membrane contactor/separator for an advanced ozone membrane reactor for treatment of recalcitrant organic pollutants in water

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

    Chan, Wai Kit, E-mail: kekyeung@ust.hk; Joueet, Justine; Heng, Samuel

    An advanced ozone membrane reactor that synergistically combines membrane distributor for ozone gas, membrane contactor for pollutant adsorption and reaction, and membrane separator for clean water production is described. The membrane reactor represents an order of magnitude improvement over traditional semibatch reactor design and is capable of complete conversion of recalcitrant endocrine disrupting compounds (EDCs) in water at less than three minutes residence time. Coating the membrane contactor with alumina and hydrotalcite (Mg/Al=3) adsorbs and traps the organics in the reaction zone resulting in 30% increase of total organic carbon (TOC) removal. Large surface area coating that diffuses surface chargesmore » from adsorbed polar organic molecules is preferred as it reduces membrane polarization that is detrimental to separation. - Graphical abstract: Advanced ozone membrane reactor synergistically combines membrane distributor for ozone, membrane contactor for sorption and reaction and membrane separator for clean water production to achieve an order of magnitude enhancement in treatment performance compared to traditional ozone reactor. Highlights: Black-Right-Pointing-Pointer Novel reactor using membranes for ozone distributor, reaction contactor and water separator. Black-Right-Pointing-Pointer Designed to achieve an order of magnitude enhancement over traditional reactor. Black-Right-Pointing-Pointer Al{sub 2}O{sub 3} and hydrotalcite coatings capture and trap pollutants giving additional 30% TOC removal. Black-Right-Pointing-Pointer High surface area coating prevents polarization and improves membrane separation and life.« less

  20. Light Modulation and Water Splitting Enhancement Using a Composite Porous GaN Structure.

    PubMed

    Yang, Chao; Xi, Xin; Yu, Zhiguo; Cao, Haicheng; Li, Jing; Lin, Shan; Ma, Zhanhong; Zhao, Lixia

    2018-02-14

    On the basis of the laterally porous GaN, we designed and fabricated a composite porous GaN structure with both well-ordered lateral and vertical holes. Compared to the plane GaN, the composite porous GaN structure with the combination of the vertical holes can help to reduce UV reflectance and increase the saturation photocurrent during water splitting by a factor of ∼4.5. Furthermore, we investigated the underlying mechanism for the enhancement of the water splitting performance using a finite-difference time-domain method. The results show that the well-ordered vertical holes can not only help to open the embedded pore channels to the electrolyte at both sides and reduce the migration distance of the gas bubbles during the water splitting reactions but also help to modulate the light field. Using this composite porous GaN structure, most of the incident light can be modulated and trapped into the nanoholes, and thus the electric fields localized in the lateral pores can increase dramatically as a result of the strong optical coupling. Our findings pave a new way to develop GaN photoelectrodes for highly efficient solar water splitting.

  1. Validation of phenol red versus gravimetric method for water reabsorption correction and study of gender differences in Doluisio's absorption technique.

    PubMed

    Tuğcu-Demiröz, Fatmanur; Gonzalez-Alvarez, Isabel; Gonzalez-Alvarez, Marta; Bermejo, Marival

    2014-10-01

    The aim of the present study was to develop a method for water flux reabsorption measurement in Doluisio's Perfusion Technique based on the use of phenol red as a non-absorbable marker and to validate it by comparison with gravimetric procedure. The compounds selected for the study were metoprolol, atenolol, cimetidine and cefadroxil in order to include low, intermediate and high permeability drugs absorbed by passive diffusion and by carrier mediated mechanism. The intestinal permeabilities (Peff) of the drugs were obtained in male and female Wistar rats and calculated using both methods of water flux correction. The absorption rate coefficients of all the assayed compounds did not show statistically significant differences between male and female rats consequently all the individual values were combined to compare between reabsorption methods. The absorption rate coefficients and permeability values did not show statistically significant differences between the two strategies of concentration correction. The apparent zero order water absorption coefficients were also similar in both correction procedures. In conclusion gravimetric and phenol red method for water reabsorption correction are accurate and interchangeable for permeability estimation in closed loop perfusion method. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Detection of an organic-non volatile compound in variable-contaminated volcanic soil samples via Time Domain Reflectometry (TDR) technique: Preliminary results

    NASA Astrophysics Data System (ADS)

    comegna, alessandro; coppola, antonio; dragonetti, giovanna; chaali, nesrine; sommella, angelo

    2014-05-01

    Hydrocarbons may be present in soils as non-aqueous phase liquids (NAPLs), which means that these organic compounds, exist as a separate and immiscible phase with respect to water and air commonly present in the soil. NAPLs, which can be accidentally introduced in the environment (for example by waste disposal sites, industrial spills, gasoline stations, etc), constitutes a serious geo-environmental problem, given the toxicity level and the high mobility. Time domain reflectometry (TDR) has became, over several decades, an important technique for water estimation in soils. In order to expand the potentiality of the TDR technique, the main objective of this study is to explore the capacity of dielectric response to detect the presence of NAPLs in volcanic soils. In laboratory, soil samples were oven dried at 105° C and passed through a 2 mm sieve. Known quantities of soil, water and NAPL (corn oil, a non-volatile and non-toxic organic compound) were mixed and repacked into plastic cylinders (16 cm high and 9.5 cm in diameter); in order to obtain forty different volumetric combinations of water and oil (i.e. θfg = θwater + θNAPL), with θNAPL varying from 0.05 to 0.40 by 0.05 cm3/cm3 increments. Data collected were employed to implement a multiphase mixing model which permitted conversion from a dielectric permittivity domain into a θf domain and vice versa. The results of this study show that, the TDR device is NAPL-sensitive, especially for θf values greater than 0.20. Further works will be built on this initial study, concentrating on improving the dielectric response-database, in order to: i) enhancing the model efficiency in terms of NAPL capability detention, and ii) validating the developed TDR interpretation tool with field results.

  3. Ubiquitous Detection of Artificial Sweeteners and Iodinated X-ray Contrast Media in Aquatic Environmental and Wastewater Treatment Plant Samples from Vietnam, The Philippines, and Myanmar.

    PubMed

    Watanabe, Yuta; Bach, Leu Tho; Van Dinh, Pham; Prudente, Maricar; Aguja, Socorro; Phay, Nyunt; Nakata, Haruhiko

    2016-05-01

    Water samples from Vietnam, The Philippines, and Myanmar were analyzed for artificial sweeteners (ASs) and iodinated X-ray contrast media (ICMs). High concentrations (low micrograms per liter) of ASs, including aspartame, saccharin, and sucralose, were found in wastewater treatment plant (WWTP) influents from Vietnam. Three ICMs, iohexol, iopamidol, and iopromide were detected in Vietnamese WWTP influents and effluents, suggesting that these ICMs are frequently used in Vietnam. ASs and ICMs were found in river water from downtown Hanoi at concentrations comparable to or lower than the concentrations in WWTP influents. The ASs and ICMs concentrations in WWTP influents and adjacent surface water significantly correlated (r (2) = 0.99, p < 0.001), suggesting that household wastewater is discharged directly into rivers in Vietnam. Acesulfame was frequently detected in northern Vietnamese groundwater, but the concentrations varied spatially by one order of magnitude even though the sampling points were very close together. This implies that poorly performing domestic septic tanks sporadically leak household wastewater into groundwater. High acesulfame, cyclamate, saccharin, and sucralose concentrations were found in surface water from Manila, The Philippines. The sucralose concentrations were one order of magnitude higher in the Manila samples than in the Vietnamese samples, indicating that more sucralose is used in The Philippines than in Vietnam. Acesulfame and cyclamate were found in surface water from Pathein (rural) and Yangon (urban) in Myanmar, but no ICMs were found in the samples. The ASs concentrations were two-three orders of magnitude lower in the samples from Myanmar than in the samples from Vietnam and The Philippines, suggesting that different amounts of ASs are used in these countries. We believe this is the first report of persistent ASs and ICMs having ubiquitous distributions in economically emerging South Asian countries.

  4. Applicability of fluidized bed reactor in recalcitrant compound degradation through advanced oxidation processes: a review.

    PubMed

    Tisa, Farhana; Abdul Raman, Abdul Aziz; Wan Daud, Wan Mohd Ashri

    2014-12-15

    Treatment of industrial waste water (e.g. textile waste water, phenol waste water, pharmaceutical etc) faces limitation in conventional treatment procedures. Advanced oxidation processes (AOPs) do not suffer from the limits of conventional treatment processes and consequently degrade toxic pollutants more efficiently. Complexity is faced in eradicating the restrictions of AOPs such as sludge formation, toxic intermediates formation and high requirement for oxidants. Increased mass-transfer in AOPs is an alternate solution to this problem. AOPs combined with Fluidized bed reactor (FBR) can be a potential choice compared to fixed bed or moving bed reactor, as AOP catalysts life-span last for only maximum of 5-10 cycles. Hence, FBR-AOPs require lesser operational and maintenance cost by reducing material resources. The time required for AOP can be minimized using FBR and also treatable working volume can be increased. FBR-AOP can process from 1 to 10 L of volume which is 10 times more than simple batch reaction. The mass transfer is higher thus the reaction time is lesser. For having increased mass transfer sludge production can be successfully avoided. The review study suggests that, optimum particle size, catalyst to reactor volume ratio, catalyst diameter and liquid or gas velocity is required for efficient FBR-AOP systems. However, FBR-AOPs are still under lab-scale investigation and for industrial application cost study is needed. Cost of FBR-AOPs highly depends on energy density needed and the mechanism of degradation of the pollutant. The cost of waste water treatment containing azo dyes was found to be US$ 50 to US$ 500 per 1000 gallons where, the cost for treating phenol water was US$ 50 to US$ 800 per 1000 gallons. The analysis for FBR-AOP costs has been found to depend on the targeted pollutant, degradation mechanism (zero order, 1st order and 2nd order) and energy consumptions by the AOPs. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. A (very) Simple Model for the Aspect Ratio of High-Order River Basins

    NASA Astrophysics Data System (ADS)

    Shelef, E.

    2017-12-01

    The structure of river networks dictates the distribution of elevation, water, and sediments across Earth's surface. Despite its intricate shape, the structure of high-order river networks displays some surprising regularities such as the consistent aspect ratio (i.e., basin's width over length) of river basins along linear mountain fronts. This ratio controls the spacing between high-order channels as well as the spacing between the depositional bodies they form. It is generally independent of tectonic and climatic conditions and is often attributed to the initial topography over which the network was formed. This study shows that a simple, cross-like channel model explains this ratio via a requirement for equal elevation gain between the outlets and drainage-divides of adjacent channels at topographic steady state. This model also explains the dependence of aspect ratio on channel concavity and the location of the widest point on a drainage divide.

  6. 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).

  7. Water distribution at the root-soil interface: is there more water next to roots?

    NASA Astrophysics Data System (ADS)

    Carminati, A.; Moradi, A.; Oswald, S.; Vetterlein, D.; Weller, U.; Vogel, H.-J.

    2009-04-01

    Plants are big water movers and have a significant impact on soil water dynamics as well as on the global water cycle. Despite the relevance of root water uptake in terrestrial ecology, the movement of water from soil to roots still presents important open questions, e.g the following two. Which are the properties of the soil near the roots? And what effect do these properties have on soil plant water relations? Most models are based on brute-force spatial averaging of soil properties and assume that the bulk soil has the same properties as the rhizosphere. However, there is evidence in the literature that the rhizosphere has specific properties that may affect water and nutrient uptake (Young 1995, Gregory 2007). In order to investigate the rhizosphere hydraulic properties and their effect on soil plant water relations, we used neutron radiography and neutron tomography to image the water content distribution in soils during plant transpiration. Rectangular (quasi-2D) and cylindrical containers were filled with sandy soil and planted with lupins (Lupinus albus). Three weeks after planting, the samples were equilibrated at water potentials of -10 and 30 hPa and have been imaged for 5 days at intervals of 6 hours. At day 5 the samples were irrigated again via capillary rise and the water distribution was monitored for 4 more days. During the first day of the drying period, regions of water depletion formed around the central part of the tap root where first order laterals were present. As the soil dried up, the picture changed: instead of less water around the roots, as commonly supposed by models, we observed that more water was present around the lateral roots. Interestingly, these regions during drying were retaining high water content, but after irrigation remained markedly drier than the bulk soil. Our hypothesis is that high water content near roots during drying and lower water content during rewetting are explained by the presence of bio-polymers exuded by roots forming a hydrogel that consists of up to 99% water at very negative water potentials (Read et al. 1999). Thanks to its high water holding capacity, this hydrogel maintains a continuous hydraulic pathway across soil and roots for an extended period of time during drying. During rewetting it adversely affects water redistribution, like a storage that needs time to fill up again. These data show for the first time in situ the potential role of mucilage in controlling water dynamics in the rhizosphere and consequences for plant water extraction. Gregory P J, Roots, rhizosphere and soil: the route to a better understanding of soil science? European Journal of Soil Science, 57: 2-12, 2006. Read D P, Gregory P J, and Bell A E. Physical properties of axenic maize root mucilage. Plant and Soil, 211: 87-91, 1999. Young I M. Variation in moisture contents between bulk soil and the rhizosheath of wheat. New Phytologist, 130: 135-139, 1995.

  8. Western and Clark's grebes use novel strategies for running on water.

    PubMed

    Clifton, Glenna T; Hedrick, Tyson L; Biewener, Andrew A

    2015-04-15

    Few vertebrates run on water. The largest animals to accomplish this feat are western and Clark's grebes (Aechmophorus occidentalis and Aechmophorus clarkii). These birds use water running to secure a mate during a display called rushing. Grebes weigh an order of magnitude more than the next largest water runners, basilisk lizards (Basilicus basiliscus), and therefore face a greater challenge to support their body weight. How do these birds produce the hydrodynamic forces necessary to overcome gravity and sustain rushing? We present the first quantitative study of water running by grebes. High-speed video recordings elucidate the hindlimb movements of grebes rushing in the wild. We complement these findings with laboratory experiments using physical models and a preserved grebe foot to estimate how slapping the water surface contributes to weight support. Our results indicate that grebes use three novel tactics to successfully run on water. First, rushing grebes use exceptionally high stride rates, reaching 10 Hz. Second, grebe foot size and high water impact speed allow grebes to generate up to 30-55% of the required weight support through water slap alone. Finally, flattened foot bones reduce downward drag, permitting grebes to retract each foot from the water laterally. Together, these mechanisms outline a water-running strategy qualitatively different from that of the only previously studied water runner, the basilisk lizard. The hydrodynamic specializations of rushing grebes could inform the design of biomimetic appendages. Furthermore, the mechanisms underlying this impressive display demonstrate that evolution can dramatically alter performance under sexual selection. © 2015. Published by The Company of Biologists Ltd.

  9. Eco-Friendly Superwetting Material for Highly Effective Separations of Oil/Water Mixtures and Oil-in-Water Emulsions.

    PubMed

    Wang, Chih-Feng; Yang, Sheng-Yi; Kuo, Shiao-Wei

    2017-02-20

    Because the treatment of oily wastewater, generated from many industrial processes, has become an increasing environmental concern, the search continues for simple, inexpensive, eco-friendly, and readily scalable processes for fabricating novel materials capable of effective oil/water separation. In this study we prepared an eco-friendly superhydrophilic and underwater superoleophobic polyvinylpyrrolidone (PVP)-modified cotton that mediated extremely efficient separations of mixtures of oil/water and oil/corrosive solutions. This PVP-modified cotton exhibited excellent antifouling properties and could be used to separate oil/water mixtures continuously for up to 20 h. Moreover, the compressed PVP-modified cotton could separate both surfactant-free and -stabilized oil-in-water emulsions with fluxes of up to 23,500 L m -2 h -1 bar -1 -a level one to two orders of magnitude higher than that possible when using traditional ultrafiltration membranes having similar rejection properties. The high performance of our PVP-modified cotton and its green, low-energy, cost-effective preparation suggest its great potential for practical applications.

  10. Eco-Friendly Superwetting Material for Highly Effective Separations of Oil/Water Mixtures and Oil-in-Water Emulsions

    NASA Astrophysics Data System (ADS)

    Wang, Chih-Feng; Yang, Sheng-Yi; Kuo, Shiao-Wei

    2017-02-01

    Because the treatment of oily wastewater, generated from many industrial processes, has become an increasing environmental concern, the search continues for simple, inexpensive, eco-friendly, and readily scalable processes for fabricating novel materials capable of effective oil/water separation. In this study we prepared an eco-friendly superhydrophilic and underwater superoleophobic polyvinylpyrrolidone (PVP)-modified cotton that mediated extremely efficient separations of mixtures of oil/water and oil/corrosive solutions. This PVP-modified cotton exhibited excellent antifouling properties and could be used to separate oil/water mixtures continuously for up to 20 h. Moreover, the compressed PVP-modified cotton could separate both surfactant-free and -stabilized oil-in-water emulsions with fluxes of up to 23,500 L m-2 h-1 bar-1—a level one to two orders of magnitude higher than that possible when using traditional ultrafiltration membranes having similar rejection properties. The high performance of our PVP-modified cotton and its green, low-energy, cost-effective preparation suggest its great potential for practical applications.

  11. Research Regarding Membrane Filtration Capacity of Water Collected from Siret River

    NASA Astrophysics Data System (ADS)

    Mihalache, I.; Pintilie, Ş. C.; Bîrsan, I. G.; Dănăila, E.; Baltă, Ş.

    2018-06-01

    In the past decade, the high demand and strict legislations regarding pure and potable water production and quality require finding new treatment technologies with higher effectiveness. When compared with conventional treatment technologies, membrane technology is a viable option in water and wastewater treatment due to high performance, ease in implementation, cost-efficiency among other advantages, also, leading to a rapid expansion in use in almost all areas of industry. Polymeric ultrafiltration membranes have been successfully used in various industries since 1969, and in later years they were studied in the water purification sector, mainly as a pre-treatment step to reduce severe fouling that could occur in reverse osmosis filtration stage. Polysulfone (PSf) was the polymer of choice in this study with two concentrations, 25 wt.% and 30 wt.%. Surface SEM morphology, roughness and water affinity were analyzed for the studied membranes. Water from Siret river was used in the permeation tests in order to analyze the retention capacity and anti-fouling ability. The present study revealed higher retention for the 30 wt.% PSf membranes, from the physico-chemical and microbiological point-of-view and lower fouling, also.

  12. Eco-Friendly Superwetting Material for Highly Effective Separations of Oil/Water Mixtures and Oil-in-Water Emulsions

    PubMed Central

    Wang, Chih-Feng; Yang, Sheng-Yi; Kuo, Shiao-Wei

    2017-01-01

    Because the treatment of oily wastewater, generated from many industrial processes, has become an increasing environmental concern, the search continues for simple, inexpensive, eco-friendly, and readily scalable processes for fabricating novel materials capable of effective oil/water separation. In this study we prepared an eco-friendly superhydrophilic and underwater superoleophobic polyvinylpyrrolidone (PVP)-modified cotton that mediated extremely efficient separations of mixtures of oil/water and oil/corrosive solutions. This PVP-modified cotton exhibited excellent antifouling properties and could be used to separate oil/water mixtures continuously for up to 20 h. Moreover, the compressed PVP-modified cotton could separate both surfactant-free and -stabilized oil-in-water emulsions with fluxes of up to 23,500 L m−2 h−1 bar−1—a level one to two orders of magnitude higher than that possible when using traditional ultrafiltration membranes having similar rejection properties. The high performance of our PVP-modified cotton and its green, low-energy, cost-effective preparation suggest its great potential for practical applications. PMID:28216617

  13. Testing the sensitivity of snowpack to climatic change in a large physiographically diverse watershed

    NASA Astrophysics Data System (ADS)

    MacDonald, R. J.; Byrne, J. M.; Kienzle, S. W.; Sauchyn, D.

    2009-12-01

    Snowpack in mountain watersheds provide a large portion of fresh water for many human and ecosystem function. Given the sensitivity of snow processes to temperature, it is likely that available water from snowpack will be reduced under future climate warming. It is important to understand how mountain environments will respond to changes in climate in order to properly manage water future resources. In order to assess potential changes in mountain snowpack and subsequent effects on water supply, we use a combination of hydrometeorological and general circulation models (GCMs). This work describes the application of the GENESYS (GENerate Earth SYstems Science input) spatial hydrometeorological model in simulating potential future changes in snowpack for the North Saskatchewan River watershed, Alberta. Snowpack in the North Saskatchewan River watershed supplies fresh water for over one million people and supports a wide range of ecosystem processes. To assess how snowpack may change in the watershed, scenarios from five GCMs are applied by perturbing the 1961-90 time series with mean changes in temperature and precipitation for the 2010-39, 2040-69 and 2070-99 periods. This study demonstrates that snowpack in the North Saskatchewan River watershed is highly susceptible to climate change and adaptive management strategies should be implemented to ensure sustainable water resources in the region.

  14. An experimental evaluation of two nonazeotropic refrigerant mixtures in a water-to-water breadboard heat pump

    NASA Astrophysics Data System (ADS)

    Kauffeld, Michael; Mulroy, William; McLinden, Mark; Didion, David

    1990-02-01

    As part of the Department of Energy/Oak Ridge National Laboratory Building Equipment Research program, the National Institute of Standards and Technology constructed an experimental, easily reconfigurable, water-to-water, breadboard heat pump apparatus in order to compare pure R22 to nonazeotropic refrigerant mixtures. Performance of the heat pump charged with a range of compositions of the binary mixtures R22/RI14 and R13/R12 were compared to R22. The advantage claimed for mixtures in this application is improved thermodynamic efficiency as a result of gliding refrigerant temperatures in the evaporator and condenser in low lift, high glide applications typical of air conditioning.

  15. Approaches and challenges of soil water monitoring in an irrigated vineyard

    NASA Astrophysics Data System (ADS)

    Nolz, Reinhard; Loiskandl, Willibald

    2016-04-01

    Monitoring of water content is an approved method to quantify certain components of the soil water balance, for example as basis for hydrological studies and soil water management. Temporal soil water data also allow controlling water status by means of demand-oriented irrigation. Regarding spatial variability of water content due to soil characteristics, plant water uptake and other non-uniformities, it is a great challenge to select a location that is most likely representing soil water status of a larger area (e.g. an irrigated field). Although such an approach might not satisfy the requirements of precision farming - which becomes more and more related to industrial agriculture - it can help improving water use efficiency of small-scale farming. In this regard, specific conditions can be found in typical vineyards in the eastern part of Austria, where grapes are grown for high quality wine production. Generally, the local dry-subhumid climate supports grape development. However, irrigation is temporarily essential in order to guarantee stable yields and high quality. As the local winegrowers traditionally control irrigation based on their experience, there is a potential to improve irrigation management by means of soil water data. In order to gain experience with regard to irrigation management, soil water status was determined in a small vineyard in Austria (47°48'16'' N, 17°01'57'' E, 118 m elevation). The vineyard was equipped with a subsurface drip irrigation system and access tubes for measuring water content in soil profiles. The latter was measured using a portable device as well as permanently installed multi-sensor capacitance probes. Soil samples were taken at chosen dates and gravimetrically analyzed in the laboratory. Water content data were analyzed using simple statistical procedures and the temporal stability concept. Soil water content was interpreted considering different environmental conditions, including rainfall and irrigation periods, and influences from tillage operations. Variability of sensor readings was substantial across the study plot. However, locations could be identified that were most likely representative for soil water monitoring. Tillage operations and weed growth in the inter-rows had a recognizable impact on soil water distribution, which also has to be considered when installing probes. Furthermore, the distance of sensors to drip emitters was of great importance for correctly interpreting data for irrigation management.

  16. Geochemical signatures of groundwater in the coastal aquifers of Thiruvallur district, south India

    NASA Astrophysics Data System (ADS)

    Senthilkumar, S.; Balasubramanian, N.; Gowtham, B.; Lawrence, J. F.

    2017-03-01

    An attempt has been made to identify the chemical processes that control the hydrochemistry of groundwater in the coastal aquifers of Thiruvallur coastal village of Thiruvallur district, Tamil Nadu, south India. The parameters such as pH, EC, TDS and major ion concentrations of Na, K, Ca, Mg, Cl, HCO3, SO4 and NO3 of the groundwater were analyzed. Abundances of these ions are in the following order Na > Ca > Mg > K and HCO3 > Cl > SO4 > NO3. The dominant water types are in the order of NaCl> mixed CaMgCl > CaHCO3 > CaNaHCO3. Water types (mixed CaHCO3, mixed CaMgCl and NaCl) suggest that the mixing of high salinity water caused from surface contamination sources such as irrigation return flow, domestic wastewater and septic tank effluents with existing water followed by ion exchange reaction processes, silicate weathering and evaporation are responsible for the groundwater chemistry of the study area. The above statement is further supported by Gibbs plot where most of the samples fall within the evaporation zone.

  17. A two-dimensional polymer synthesized at the air/water interface.

    PubMed

    Schlüter, A Dieter; Müller, Vivian; Hinaut, Antoine; Moradi, Mina; Baljozovic, Milos; Jung, Thomas; Shahgaldian, Patrick; Möhwald, Helmuth; Hofer, Gregor; Kröger, Martin; King, Benjamin; Meyer, Ernst; Glatzel, Thilo

    2018-06-11

    A trifunctional, partially fluorinated anthracene-substituted triptycene monomer is spread at the air/water interface into a monolayer, which is transformed into a long-range ordered 2D polymer by irradiation with a standard ultraviolet lamp using 365 nm light. The polymer is analyzed by Brewster angle microscopy directly at this interface and by scanning tunneling microscopy measurements and non-contact atomic force microscopy (nc-AFM), both after transfer from below the interface onto highly oriented pyrolytic graphite and then into ultra-high vacuum. Both methods confirm a network structure, the lattice parameters of which are virtually identical to a structural model network based on X-ray diffractometry of a closely related 2D polymer unequivocally established in a single crystal. The nc-AFM images are obtained with unprecedentedly high resolution and prove long-range order over areas of at least 300 × 300 nm2. As required for a 2D polymer, the pore sizes are monodisperse, except for the regions, where the network is somewhat stretched because it spans over protrusions. Together with a previous report on the nature of the cross-links in this network, the structural information provided here leaves no doubt that a 2D polymer has been synthesized under ambient conditions at an air/water interface. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Morphology and Kinetics of Growth of CaCO3 Precipitates Formed in Saline Water at 30°C

    NASA Astrophysics Data System (ADS)

    Sui, Xin; Wang, Baohui; Wu, Haiming

    2018-02-01

    The crystallization kinetics and morphology of CaCO3 crystals precipitated from the high salinity oilfield water were studied. The crystallization kinetics measurements show that nucleation and nuclei growth obey the first order reaction kinetics. The induction period of precipitation is extended in the high salinity solutions. Morphological studies show that impurity ions remain mostly in the solution phase instead of filling the CaCO3 crystal lattice. The morphology of CaCO3 precipitates can be changed from a smooth surface (calcite) to rough spheres (vaterite), and spindle rod bundles, or spherical, ellipsoid, flowers, plates and other shapes (aragonite).

  19. Methods for assessing long-term mean pathogen count in drinking water and risk management implications.

    PubMed

    Englehardt, James D; Ashbolt, Nicholas J; Loewenstine, Chad; Gadzinski, Erik R; Ayenu-Prah, Albert Y

    2012-06-01

    Recently pathogen counts in drinking and source waters were shown theoretically to have the discrete Weibull (DW) or closely related discrete growth distribution (DGD). The result was demonstrated versus nine short-term and three simulated long-term water quality datasets. These distributions are highly skewed such that available datasets seldom represent the rare but important high-count events, making estimation of the long-term mean difficult. In the current work the methods, and data record length, required to assess long-term mean microbial count were evaluated by simulation of representative DW and DGD waterborne pathogen count distributions. Also, microbial count data were analyzed spectrally for correlation and cycles. In general, longer data records were required for more highly skewed distributions, conceptually associated with more highly treated water. In particular, 500-1,000 random samples were required for reliable assessment of the population mean ±10%, though 50-100 samples produced an estimate within one log (45%) below. A simple correlated first order model was shown to produce count series with 1/f signal, and such periodicity over many scales was shown in empirical microbial count data, for consideration in sampling. A tiered management strategy is recommended, including a plan for rapid response to unusual levels of routinely-monitored water quality indicators.

  20. Prediction of storm transfers and annual loads with data-based mechanistic models using high-frequency data

    NASA Astrophysics Data System (ADS)

    Ockenden, Mary C.; Tych, Wlodek; Beven, Keith J.; Collins, Adrian L.; Evans, Robert; Falloon, Peter D.; Forber, Kirsty J.; Hiscock, Kevin M.; Hollaway, Michael J.; Kahana, Ron; Macleod, Christopher J. A.; Villamizar, Martha L.; Wearing, Catherine; Withers, Paul J. A.; Zhou, Jian G.; Benskin, Clare McW. H.; Burke, Sean; Cooper, Richard J.; Freer, Jim E.; Haygarth, Philip M.

    2017-12-01

    Excess nutrients in surface waters, such as phosphorus (P) from agriculture, result in poor water quality, with adverse effects on ecological health and costs for remediation. However, understanding and prediction of P transfers in catchments have been limited by inadequate data and over-parameterised models with high uncertainty. We show that, with high temporal resolution data, we are able to identify simple dynamic models that capture the P load dynamics in three contrasting agricultural catchments in the UK. For a flashy catchment, a linear, second-order (two pathways) model for discharge gave high simulation efficiencies for short-term storm sequences and was useful in highlighting uncertainties in out-of-bank flows. A model with non-linear rainfall input was appropriate for predicting seasonal or annual cumulative P loads where antecedent conditions affected the catchment response. For second-order models, the time constant for the fast pathway varied between 2 and 15 h for all three catchments and for both discharge and P, confirming that high temporal resolution data are necessary to capture the dynamic responses in small catchments (10-50 km2). The models led to a better understanding of the dominant nutrient transfer modes, which will be helpful in determining phosphorus transfers following changes in precipitation patterns in the future.

  1. Scale and legacy controls on catchment nutrient export regimes

    NASA Astrophysics Data System (ADS)

    Howden, N. J. K.; Burt, T.; Worrall, F.

    2017-12-01

    Nutrient dynamics in river catchments are complex: water and chemical fluxes are highly variable in low-order streams, but this variability declines as fluxes move through higher-order reaches. This poses a major challenge for process understanding as much effort is focussed on long-term monitoring of the main river channel (a high-order reach), and therefore the data available to support process understanding are predominantly derived from sites where much of the transient response of nutrient export is masked by the effect of averaging over both space and time. This may be further exacerbated at all scales by the accumulation of legacy nutrient sources in soils, aquifers and pore waters, where historical activities have led to nutrient accumulation where the catchment system is transport limited. Therefore it is of particular interest to investigate how the variability of nutrient export changes both with catchment scale (from low to high-order catchment streams) and with the presence of legacy sources, such that the context of infrequent monitoring on high-order streams can be better understood. This is not only a question of characterising nutrient export regimes per se, but also developing a more thorough understanding of how the concepts of scale and legacy may modify the statistical characteristics of observed responses across scales in both space and time. In this paper, we use synthetic data series and develop a model approach to consider how space and timescales combine with impacts of legacy sources to influence observed variability in catchment export. We find that: increasing space and timescales tend to reduce the observed variance in nutrient exports, due to an increase in travel times and greater mixing, and therefore averaging, of sources; increasing the influence of legacy sources inflates the variance, with the level of inflation dictated by the residence time of the respective sources.

  2. Analyzing the Adaptive Mesh Refinement (AMR) Characteristics of a High-Order 2D Cubed-Sphere Shallow-Water Model

    DOE PAGES

    Ferguson, Jared O.; Jablonowski, Christiane; Johansen, Hans; ...

    2016-11-09

    Adaptive mesh refinement (AMR) is a technique that has been featured only sporadically in atmospheric science literature. This study aims to demonstrate the utility of AMR for simulating atmospheric flows. Several test cases are implemented in a 2D shallow-water model on the sphere using the Chombo-AMR dynamical core. This high-order finite-volume model implements adaptive refinement in both space and time on a cubed-sphere grid using a mapped-multiblock mesh technique. The tests consist of the passive advection of a tracer around moving vortices, a steady-state geostrophic flow, an unsteady solid-body rotation, a gravity wave impinging on a mountain, and the interactionmore » of binary vortices. Both static and dynamic refinements are analyzed to determine the strengths and weaknesses of AMR in both complex flows with small-scale features and large-scale smooth flows. The different test cases required different AMR criteria, such as vorticity or height-gradient based thresholds, in order to achieve the best accuracy for cost. The simulations show that the model can accurately resolve key local features without requiring global high-resolution grids. The adaptive grids are able to track features of interest reliably without inducing noise or visible distortions at the coarse–fine interfaces. Finally and furthermore, the AMR grids keep any degradations of the large-scale smooth flows to a minimum.« less

  3. High frequency measurements of reach scale nitrogen uptake in a fourth order river with contrasting hydromorphology and variable water chemistry (Weiße Elster, Germany)

    NASA Astrophysics Data System (ADS)

    Kunz, Julia Vanessa; Hensley, Robert; Brase, Lisa; Borchardt, Dietrich; Rode, Michael

    2017-01-01

    River networks exhibit a globally important capacity to retain and process nitrogen. However direct measurement of in-stream removal in higher order streams and rivers has been extremely limited. The recent advent of automated sensors has allowed high frequency measurements, and the development of new passive methods of quantifying nitrogen uptake which are scalable across river size. Here we extend these methods to higher order streams with anthropogenically elevated nitrogen levels, substantial tributaries, complex input signals, and multiple N species. We use a combination of two station time-series and longitudinal profiling of nitrate to assess differences in nitrogen processing dynamics in a natural versus a channelized impounded reach with WWTP effluent impacted water chemistry. Our results suggest that net mass removal rates of nitrate were markedly higher in the unmodified reach. Additionally, seasonal variations in temperature and insolation affected the relative contribution of assimilatory versus dissimilatory uptake processes, with the latter exhibiting a stronger positive dependence on temperature. From a methodological perspective, we demonstrate that a mass balance approach based on high frequency data can be useful in deriving quantitative uptake estimates, even under dynamic inputs and lateral tributary inflow. However, uncertainty in diffuse groundwater inputs and more importantly the effects of alternative nitrogen species, in this case ammonium, pose considerable challenges to this method.

  4. Analyzing the Adaptive Mesh Refinement (AMR) Characteristics of a High-Order 2D Cubed-Sphere Shallow-Water Model

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

    Ferguson, Jared O.; Jablonowski, Christiane; Johansen, Hans

    Adaptive mesh refinement (AMR) is a technique that has been featured only sporadically in atmospheric science literature. This study aims to demonstrate the utility of AMR for simulating atmospheric flows. Several test cases are implemented in a 2D shallow-water model on the sphere using the Chombo-AMR dynamical core. This high-order finite-volume model implements adaptive refinement in both space and time on a cubed-sphere grid using a mapped-multiblock mesh technique. The tests consist of the passive advection of a tracer around moving vortices, a steady-state geostrophic flow, an unsteady solid-body rotation, a gravity wave impinging on a mountain, and the interactionmore » of binary vortices. Both static and dynamic refinements are analyzed to determine the strengths and weaknesses of AMR in both complex flows with small-scale features and large-scale smooth flows. The different test cases required different AMR criteria, such as vorticity or height-gradient based thresholds, in order to achieve the best accuracy for cost. The simulations show that the model can accurately resolve key local features without requiring global high-resolution grids. The adaptive grids are able to track features of interest reliably without inducing noise or visible distortions at the coarse–fine interfaces. Finally and furthermore, the AMR grids keep any degradations of the large-scale smooth flows to a minimum.« less

  5. Improving catchment scale water quality modelling with continuous high resolution monitoring of metals in runoff

    NASA Astrophysics Data System (ADS)

    Saari, Markus; Rossi, Pekka; Blomberg von der Geest, Kalle; Mäkinen, Ari; Postila, Heini; Marttila, Hannu

    2017-04-01

    High metal concentrations in natural waters is one of the key environmental and health problems globally. Continuous in-situ analysis of metals from runoff water is technically challenging but essential for the better understanding of processes which lead to pollutant transport. Currently, typical analytical methods for monitoring elements in liquids are off-line laboratory methods such as ICP-OES (Inductively Coupled Plasma Optical Emission Spectroscopy) and ICP-MS (ICP combined with a mass spectrometer). Disadvantage of the both techniques is time consuming sample collection, preparation, and off-line analysis at laboratory conditions. Thus use of these techniques lack possibility for real-time monitoring of element transport. We combined a novel high resolution on-line metal concentration monitoring with catchment scale physical hydrological modelling in Mustijoki river in Southern Finland in order to study dynamics of processes and form a predictive warning system for leaching of metals. A novel on-line measurement technique based on micro plasma emission spectroscopy (MPES) is tested for on-line detection of selected elements (e.g. Na, Mg, Al, K, Ca, Fe, Ni, Cu, Cd and Pb) in runoff waters. The preliminary results indicate that MPES can sufficiently detect and monitor metal concentrations from river water. Water and Soil Assessment Tool (SWAT) catchment scale model was further calibrated with high resolution metal concentration data. We show that by combining high resolution monitoring and catchment scale physical based modelling, further process studies and creation of early warning systems, for example to optimization of drinking water uptake from rivers, can be achieved.

  6. Remote measurement of high preeruptive water vapor emissions at Sabancaya volcano by passive differential optical absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Kern, Christoph; Masias, Pablo; Apaza, Fredy; Reath, Kevin A.; Platt, Ulrich

    2017-05-01

    Water (H2O) is by far the most abundant volcanic volatile species and plays a predominant role in driving volcanic eruptions. However, numerous difficulties associated with making accurate measurements of water vapor in volcanic plumes have limited their use as a diagnostic tool. Here we present the first detection of water vapor in a volcanic plume using passive visible-light differential optical absorption spectroscopy (DOAS). Ultraviolet and visible-light DOAS measurements were made on 21 May 2016 at Sabancaya Volcano, Peru. We find that Sabancaya's plume contained an exceptionally high relative water vapor abundance 6 months prior to its November 2016 eruption. Our measurements yielded average sulfur dioxide (SO2) emission rates of 800-900 t/d, H2O emission rates of around 250,000 t/d, and an H2O/SO2 molecular ratio of 1000 which is about an order of magnitude larger than typically found in high-temperature volcanic gases. We attribute the high water vapor emissions to a boiling-off of Sabancaya's hydrothermal system caused by intrusion of magma to shallow depths. This hypothesis is supported by a significant increase in the thermal output of the volcanic edifice detected in infrared satellite imagery leading up to and after our measurements. Though the measurement conditions encountered at Sabancaya were very favorable for our experiment, we show that visible-light DOAS systems could be used to measure water vapor emissions at numerous other high-elevation volcanoes. Such measurements would provide observatories with additional information particularly useful for forecasting eruptions at volcanoes harboring significant hydrothermal systems.

  7. Peptide π-Electron Conjugates: Organic Electronics for Biology?

    PubMed

    Ardoña, Herdeline Ann M; Tovar, John D

    2015-12-16

    Highly ordered arrays of π-conjugated molecules are often viewed as a prerequisite for effective charge-transporting materials. Studies involving these materials have traditionally focused on organic electronic devices, with more recent emphasis on biological systems. In order to facilitate the transition to biological environments, biomolecules that can promote hierarchical ordering and water solubility are often covalently appended to the π-electron unit. This review highlights recent work on π-conjugated systems bound to peptide moieties that exhibit self-assembly and aims to provide an overview on the development and emerging applications of peptide-based supramolecular π-electron systems.

  8. Dual-frequency focused ultrasound using optoacoustic and piezoelectric transmitters for single-pulsed free-field cavitation in water

    NASA Astrophysics Data System (ADS)

    Baac, Hyoung Won; Lee, Taehwa; Ok, Jong G.; Hall, Timothy; Jay Guo, L.

    2013-12-01

    Pulsed ultrasonic cavitation is a promising modality for non-contact targeted therapy, enabling mechanical ablation of the tissue. We demonstrate a spatio-temporal superposition approach of two ultrasound pulses (high and low frequencies) producing a tight cavitation zone of 100 μm in water, which is an-order-of-magnitudes smaller than those obtained by the existing high-amplitude transducers. Particularly, laser-generated focused ultrasound (LGFU) was employed for the high-frequency operation (15 MHz). As demonstrated, LGFU plays a primary role to define the cavitation zone. The generation rate of cavitation bubbles could be dramatically increased up to 4.1% (cf. 0.06% without the superposition) with moderated threshold requirement.

  9. Numerical Investigation of Laser Propulsion for Transport in Water Environment

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

    Han Bing; Li Beibei; Zhang Hongchao

    Problems that cumber the development of the laser propulsion in atmosphere and vacuum are discussed. Based on the theory of interaction between high-intensity laser and materials, as air and water, it is proved that transport in water environment can be impulsed by laser. The process of laser propulsion in water is investigated theoretically and numerically. It shows that not only the laser induced plasma shock wave, but also the laser induced bubble oscillation shock waves and the pressure induced by the collapsing bubble can be used. Many experimental results show that the theory and the numerical results are valid. Themore » numerical result of the contribution of every propulsion source is given in percentage. And the maximum momentum coupling coefficient Cm is given. Laser propulsion in water environment can be applied in many fields. For example, it can provide highly controllable forces of the order of micro-Newton ({mu}N) in microsystems, such as the MEMS (Micro-electromechanical Systems). It can be used as minimally invasive surgery tools of high temporal and spatial resolution. It can be used as the propulsion source in marine survey and exploitation.« less

  10. "Carbon gain vs. water saving, growth vs. defence": two dilemmas with soluble phenolics as a joker.

    PubMed

    Karabourniotis, George; Liakopoulos, Georgios; Nikolopoulos, Dimosthenis; Bresta, Panagiota; Stavroulaki, Vassiliki; Sumbele, Sally

    2014-10-01

    Despite that phenolics are considered as a major weapon against herbivores and pathogens, the primal reason for their evolution may have been the imperative necessity for their UV-absorbing and antioxidant properties in order for plants to compensate for the adverse terrestrial conditions. In dry climates the choice concerning the first dilemma (carbon gain vs. water saving) needs the appropriate structural and metabolic modulations, which protect against stresses such as high UV and visible radiation or drought, but reduce photosynthesis and increase oxidative pressure. Thus, when water saving is chosen, priority is given to protection (including phenolic synthesis), instead of carbon gain and hence growth. At the global level, the different choices by the individual species are expressed by an interspecific negative relationship between total phenolics and photosynthesis. On the other hand, the accumulation of phenolics in water saving plants offers additional defensive functions because these multifunctional compounds can also act as pro-oxidant, antifeeding or toxic factors. Therefore phenolics, as biochemical jokers, can give the answer to both dilemmas: water saving involves high concentrations of phenolics which also offer high level of defence. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  11. Nekton use of intertidal creek edges in low salinity salt marshes of the Yangtze River estuary along a stream-order gradient

    NASA Astrophysics Data System (ADS)

    Jin, Binsong; Qin, Haiming; Xu, Wang; Wu, Jihua; Zhong, Junsheng; Lei, Guangchun; Chen, Jiakuan; Fu, Cuizhang

    2010-07-01

    Non-vegetated creek edges were investigated to explore spatial nekton use patterns in a low salinity intertidal salt marsh creek network of the Yangtze River estuary along a stream-order gradient with four creek orders. Non-vegetated creek edges were arbitrarily defined as the approximately 3 m extending from the creek bank (the marsh-creek interface) into open water. Nekton was sampled using seine nets during daytime high slack water during spring tides for two or three days each in May through July 2008. Twenty-three nekton species (16 fishes and 7 crustaceans) were caught during the study. Fishes were dominated by gobies ( Mugilogobius abei, Periophthalmus magnuspinnatus, Periophthalmus modestus, Synechogobius ommaturus), mullets ( Chelon haematocheilus, Liza affinis) and Chinese sea bass ( Lateolabrax maculatus). Crustaceans were dominated by mud crab ( Helice tientsinensis) and white prawn ( Exopalaemon carinicauda). Rank abundance curves revealed higher evenness of nekton assemblages in lower-order creeks compared to higher-order creeks. Fish abundance tended to increase with increasing creek order. Crustacean abundance was higher in the first-third order creeks than in the fourth-order creek. Dominant nekton species displayed various trends in abundance and length-frequency distributions along the stream-order gradient. The spatial separation of nekton assemblages between the first-third order creeks and the fourth-order creek could be attributed to geomorphological factors (distance to mouth and cross-sectional area). These findings indicate that both lower- and higher-order creek edges play important yet different roles for nekton species and life history stages in salt marshes.

  12. High levels of faecal contamination in drinking groundwater and recreational water due to poor sanitation, in the sub-rural neighbourhoods of Kinshasa, Democratic Republic of the Congo.

    PubMed

    Kayembe, John M; Thevenon, Florian; Laffite, Amandine; Sivalingam, Periyasamy; Ngelinkoto, Patience; Mulaji, Crispin K; Otamonga, Jean-Paul; Mubedi, Josué I; Poté, John

    2018-04-01

    In many urban and peri-urban areas of developing countries, shallow wells and untreated water from urban rivers are used for domestic purposes, including drinking water supply, population bathing and irrigation for urban agriculture. The evaluation and monitoring of water quality are therefore necessary for preventing potential human risk associated with the exposure to contaminated water. In this study, physicochemical and bacteriological parameters were assessed in an urban river (named Kokolo Canal/Jerusalem River) draining the municipality of Lingwala (City of Kinshasa, Democratic Republic of the Congo) and in two shallow wells used as drinking water supplies, during the wet and dry seasons in order to estimate the seasonal variation of contamination. The faecal indicator bacteria (FIB) isolated strains (Escherichia coli (E. coli) and Enterococcus (ENT)) from water and surface sediment, were characterized for human-specific bacteroides by molecular approach. The results revealed very high faecal contamination of water from the shallow wells, and of water and sediments from the river, during both wet and dry seasons. During the wet season, E. coli reached the values of 18.6 × 10 5 and 4.9 × 10 5  CFU 100 mL -1 in Kokolo Canal and shallow wells, respectively; and Enterococcus reached the values of 7.4 × 10 4 and 2.7 × 10 4  CFU 100 mL -1 . Strong mutually positive correlation was observed between E. coli and ENT, with the range of R-value being 0.93 < r < 0.97 (p-value < 0.001, n = 15). The PCR assays for human-specific Bacteroides indicated that more than 98% of 500 isolated FIB strains were of human origin, pointing out the effect of poor household sanitation practices on surface water but also on groundwater contamination. The water samples from the shallow wells and Kokolo Canal were highly polluted with faecal matter in both seasons. However, the pollution level was significantly higher during the wet season compared to the dry season. Physicochemical analysis revealed also very high water electrical conductivity, with values much higher than the recommended limits of the World Health Organization guideline for drinking water. These results highlight the potential human health risk associated with the exposure to water contamination from shallow wells and Kokolo Canal, due to the very high level of human FIB. Rapid, unplanned and uncontrolled population growth in the city of Kinshasa is increasing considerably the water demand, whereas there is a dramatic lack of appropriate sanitation and wastewater facilities, as well as of faecal sludge (and solid waste) management and treatment. The lack of hygiene and the practice of open defecation is leading to the degradation of water quality, consequently the persistence of waterborne diseases in the neighbourhoods of sub-rural municipalities, and there is a growing threat to the sustainability to water resources and water quality. The results of this study should encourage municipality policy and strategy on increasing the access to safely managed sanitation services; in order to better protect surface water and groundwater sources, and limit the proliferation of epidemics touching regularly the city. Copyright © 2018 Elsevier GmbH. All rights reserved.

  13. Joint optimization of regional water-power systems

    NASA Astrophysics Data System (ADS)

    Pereira-Cardenal, Silvio J.; Mo, Birger; Gjelsvik, Anders; Riegels, Niels D.; Arnbjerg-Nielsen, Karsten; Bauer-Gottwein, Peter

    2016-06-01

    Energy and water resources systems are tightly coupled; energy is needed to deliver water and water is needed to extract or produce energy. Growing pressure on these resources has raised concerns about their long-term management and highlights the need to develop integrated solutions. A method for joint optimization of water and electric power systems was developed in order to identify methodologies to assess the broader interactions between water and energy systems. The proposed method is to include water users and power producers into an economic optimization problem that minimizes the cost of power production and maximizes the benefits of water allocation, subject to constraints from the power and hydrological systems. The method was tested on the Iberian Peninsula using simplified models of the seven major river basins and the power market. The optimization problem was successfully solved using stochastic dual dynamic programming. The results showed that current water allocation to hydropower producers in basins with high irrigation productivity, and to irrigation users in basins with high hydropower productivity was sub-optimal. Optimal allocation was achieved by managing reservoirs in very distinct ways, according to the local inflow, storage capacity, hydropower productivity, and irrigation demand and productivity. This highlights the importance of appropriately representing the water users' spatial distribution and marginal benefits and costs when allocating water resources optimally. The method can handle further spatial disaggregation and can be extended to include other aspects of the water-energy nexus.

  14. ACCELERATED SOLVENT EXTRACTION COMBINED WITH ...

    EPA Pesticide Factsheets

    A research project was initiated to address a recurring problem of elevated detection limits above required risk-based concentrations for the determination of semivolatile organic compounds in high moisture content solid samples. This project was initiated, in cooperation with the EPA Region 1 Laboratory, under the Regional Methods Program administered through the ORD Office of Science Policy. The aim of the project was to develop an approach for the rapid removal of water in high moisture content solids (e.g., wetland sediments) in preparation for analysis via Method 8270. Alternative methods for water removal have been investigated to enhance compound solid concentrations and improve extraction efficiency, with the use of pressure filtration providing a high-throughput alternative for removal of the majority of free water in sediments and sludges. In order to eliminate problems with phase separation during extraction of solids using Accelerated Solvent Extraction, a variation of a water-isopropanol extraction method developed at the USGS National Water Quality Laboratory in Denver, CO is being employed. The concentrations of target compounds in water-isopropanol extraction fluids are subsequently analyzed using an automated Solid Phase Extraction (SPE)-GC/MS method developed in our laboratory. The coupled approaches for dewatering, extraction, and target compound identification-quantitation provide a useful alternative to enhance sample throughput for Me

  15. RF Path and Absorption Loss Estimation for Underwater Wireless Sensor Networks in Different Water Environments

    PubMed Central

    Qureshi, Umair Mujtaba; Shaikh, Faisal Karim; Aziz, Zuneera; Shah, Syed M. Zafi S.; Sheikh, Adil A.; Felemban, Emad; Qaisar, Saad Bin

    2016-01-01

    Underwater Wireless Sensor Network (UWSN) communication at high frequencies is extremely challenging. The intricacies presented by the underwater environment are far more compared to the terrestrial environment. The prime reason for such intricacies are the physical characteristics of the underwater environment that have a big impact on electromagnetic (EM) signals. Acoustics signals are by far the most preferred choice for underwater wireless communication. Because high frequency signals have the luxury of large bandwidth (BW) at shorter distances, high frequency EM signals cannot penetrate and propagate deep in underwater environments. The EM properties of water tend to resist their propagation and cause severe attenuation. Accordingly, there are two questions that need to be addressed for underwater environment, first what happens when high frequency EM signals operating at 2.4 GHz are used for communication, and second which factors affect the most to high frequency EM signals. To answer these questions, we present real-time experiments conducted at 2.4 GHz in terrestrial and underwater (fresh water) environments. The obtained results helped in studying the physical characteristics (i.e., EM properties, propagation and absorption loss) of underwater environments. It is observed that high frequency EM signals can propagate in fresh water at a shallow depth only and can be considered for a specific class of applications such as water sports. Furthermore, path loss, velocity of propagation, absorption loss and the rate of signal loss in different underwater environments are also calculated and presented in order to understand why EM signals cannot propagate in sea water and oceanic water environments. An optimal solk6ution for underwater communication in terms of coverage distance, bandwidth and nature of communication is presented, along with possible underwater applications of UWSNs at 2.4 GHz. PMID:27322263

  16. RF Path and Absorption Loss Estimation for Underwater Wireless Sensor Networks in Different Water Environments.

    PubMed

    Qureshi, Umair Mujtaba; Shaikh, Faisal Karim; Aziz, Zuneera; Shah, Syed M Zafi S; Sheikh, Adil A; Felemban, Emad; Qaisar, Saad Bin

    2016-06-16

    Underwater Wireless Sensor Network (UWSN) communication at high frequencies is extremely challenging. The intricacies presented by the underwater environment are far more compared to the terrestrial environment. The prime reason for such intricacies are the physical characteristics of the underwater environment that have a big impact on electromagnetic (EM) signals. Acoustics signals are by far the most preferred choice for underwater wireless communication. Because high frequency signals have the luxury of large bandwidth (BW) at shorter distances, high frequency EM signals cannot penetrate and propagate deep in underwater environments. The EM properties of water tend to resist their propagation and cause severe attenuation. Accordingly, there are two questions that need to be addressed for underwater environment, first what happens when high frequency EM signals operating at 2.4 GHz are used for communication, and second which factors affect the most to high frequency EM signals. To answer these questions, we present real-time experiments conducted at 2.4 GHz in terrestrial and underwater (fresh water) environments. The obtained results helped in studying the physical characteristics (i.e., EM properties, propagation and absorption loss) of underwater environments. It is observed that high frequency EM signals can propagate in fresh water at a shallow depth only and can be considered for a specific class of applications such as water sports. Furthermore, path loss, velocity of propagation, absorption loss and the rate of signal loss in different underwater environments are also calculated and presented in order to understand why EM signals cannot propagate in sea water and oceanic water environments. An optimal solk6ution for underwater communication in terms of coverage distance, bandwidth and nature of communication is presented, along with possible underwater applications of UWSNs at 2.4 GHz.

  17. Observations of Seafloor Roughness in a Tidally Modulated Inlet

    NASA Astrophysics Data System (ADS)

    Lippmann, T. C.; Hunt, J.

    2014-12-01

    The vertical structure of shallow water flows are influenced by the presence of a bottom boundary layer, which spans the water column for long period waves or mean flows. The nature of the boundary is determined in part by the roughness elements that make up the seafloor, and includes sometimes complex undulations associated with regular and irregular shaped bedforms whose scales range several orders of magnitude from orbital wave ripples (10-1 m) to mega-ripples (100 m) and even larger features (101-103) such as sand waves, bars, and dunes. Modeling efforts often parameterize the effects of roughness elements on flow fields, depending on the complexity of the boundary layer formulations. The problem is exacerbated by the transient nature of bedforms and their large spatial extent and variability. This is particularly important in high flow areas with large sediment transport, such as tidally dominated sandy inlets like New River Inlet, NC. Quantification of small scale seafloor variability over large spatial areas requires the use of mobile platforms that can measure with fine scale (order cm) accuracy in wide swaths. The problem is difficult in shallow water where waves and currents are large, and water clarity is often limited. In this work, we present results from bathymetric surveys obtained with the Coastal Bathymetry Survey System, a personal watercraft equipped with a Imagenex multibeam acoustic echosounder and Applanix POS-MV 320 GPS-aided inertial measurement unit. This system is able to measure shallow water seafloor bathymetry and backscatter intensity with very fine scale (10-1 m) resolution and over relatively large scales (103 m) in the presence of high waves and currents. Wavenumber spectra show that the noise floor of the resolved multibeam bathymetry is on the order of 2.5 - 5 cm in amplitude, depending on water depths ranging 2 - 6 m, and about 30 cm in wavelength. Seafloor roughness elements are estimated from wavenumber spectra across the inlet from bathymetric maps of the seafloor obtained with 10-25 cm horizontal resolution. Implications of the effects of the bottom variability on the vertical structure of the currents will be discussed. This work was supported by ONR and NOAA.

  18. A Demonstration of the Continuous Phase (Second-Order) Transition of a Binary Liquid System in the Region around Its Critical Point

    ERIC Educational Resources Information Center

    Johnson, Michael R.

    2006-01-01

    In most general chemistry and introductory physical chemistry classes, critical point is defined as that temperature-pressure point on a phase diagram where the liquid-gas interface disappears, a phenomenon that generally occurs at relatively high temperatures or high pressures. Two examples are: water, with a critical point at 647 K (critical…

  19. Mutual physiological genetic mechanism of plant high water use efficiency and nutrition use efficiency.

    PubMed

    Cao, Hong-Xing; Zhang, Zheng-Bin; Xu, Ping; Chu, Li-Ye; Shao, Hong-Bo; Lu, Zhao-Hua; Liu, Jun-Hong

    2007-05-15

    Water deficiency and lower fertilizer utilization efficiency are major constraints of productivity and yield stability. Improvements of crop water use efficiency (WUE) and nutrient use efficiency (NUE) is becoming an important objective in crop breeding. With the introduction of new physiological and biological approaches, we can better understand the mutual genetics mechanism of high use efficiency of water and nutrient. Much work has been done in past decades mainly including the interactions between different fertilizers and water influences on root characteristics and crop growth. Fertilizer quantity and form were regulated in order to improve crop WUE. The crop WUE and NUE shared the same increment tendency during evolution process; some genes associated with WUE and NUE have been precisely located and marked on the same chromosomes, some genes related to WUE and NUE have been cloned and transferred into wheat and rice and other plants, they can enhance water and nutrient use efficiency. The proteins transporting nutrient and water were identified such as some water channel proteins. The advance on the mechanism of higher water and nutrient use efficiency in crop was reviewed in this article, and it could provide some useful information for further research on WUE and NUE in crop.

  20. Hydro-ecological controls on dissolved carbon dynamics in groundwater and export to streams in a temperate pine forest

    NASA Astrophysics Data System (ADS)

    Deirmendjian, Loris; Loustau, Denis; Augusto, Laurent; Lafont, Sébastien; Chipeaux, Christophe; Poirier, Dominique; Abril, Gwenaël

    2018-02-01

    We studied the export of dissolved inorganic carbon (DIC) and dissolved organic carbon (DOC) from forested shallow groundwater to first-order streams, based on groundwater and surface water sampling and hydrological data. The selected watershed was particularly convenient for such study, with a very low slope, with pine forest growing on sandy permeable podzol and with hydrology occurring exclusively through drainage of shallow groundwater (no surface runoff). A forest plot was instrumented for continuous eddy covariance measurements of precipitation, evapotranspiration, and net ecosystem exchanges of sensible and latent heat fluxes as well as CO2 fluxes. Shallow groundwater was sampled with three piezometers located in different plots, and surface waters were sampled in six first-order streams; river discharge and drainage were modeled based on four gauging stations. On a monthly basis and on the plot scale, we found a good consistency between precipitation on the one hand and the sum of evapotranspiration, shallow groundwater storage and drainage on the other hand. DOC and DIC stocks in groundwater and exports to first-order streams varied drastically during the hydrological cycle, in relation with water table depth and amplitude. In the groundwater, DOC concentrations were maximal in winter when the water table reached the superficial organic-rich layer of the soil. In contrast, DIC (in majority excess CO2) in groundwater showed maximum concentrations at low water table during late summer, concomitant with heterotrophic conditions of the forest plot. Our data also suggest that a large part of the DOC mobilized at high water table was mineralized to DIC during the following months within the groundwater itself. In first-order streams, DOC and DIC followed an opposed seasonal trend similar to groundwater but with lower concentrations. On an annual basis, leaching of carbon to streams occurred as DIC and DOC in similar proportion, but DOC export occurred in majority during short periods of the highest water table, whereas DIC export was more constant throughout the year. Leaching of forest carbon to first-order streams represented a small portion (approximately 2 %) of the net land CO2 sink at the plot. In addition, approximately 75 % of the DIC exported from groundwater was not found in streams, as it returned very fast to the atmosphere through CO2 degassing.

  1. Groundwater salinity and hydrochemical processes in the volcano-sedimentary aquifer of La Aldea, Gran Canaria, Canary Islands, Spain.

    PubMed

    Cruz-Fuentes, Tatiana; Cabrera, María del Carmen; Heredia, Javier; Custodio, Emilio

    2014-06-15

    The origin of the groundwater salinity and hydrochemical conditions of a 44km(2) volcano-sedimentary aquifer in the semi-arid to arid La Aldea Valley (western Gran Canaria, Spain) has been studied, using major physical and chemical components. Current aquifer recharge is mainly the result of irrigation return flows and secondarily that of rainfall infiltration. Graphical, multivariate statistical and modeling tools have been applied in order to improve the hydrogeological conceptual model and identify the natural and anthropogenic factors controlling groundwater salinity. Groundwater ranges from Na-Cl-HCO3 type for moderate salinity water to Na-Mg-Cl-SO4 type for high salinity water. This is mainly the result of atmospheric airborne salt deposition; silicate weathering, and recharge incorporating irrigation return flows. High evapotranspiration produces significant evapo-concentration leading to relative high groundwater salinity in the area. Under average conditions, about 70% of the water used for intensive agricultural exploitation in the valley comes from three low salinity water runoff storage reservoirs upstream, out of the area, while the remaining 30% derives from groundwater. The main alluvial aquifer behaves as a short turnover time reservoir that adds to the surface waters to complement irrigation water supply in dry periods, when it reaches 70% of irrigation water requirements. The high seasonality and intra-annual variability of water demand for irrigation press on decision making on aquifer use by a large number of aquifer users acting on their own. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Water desalination with a single-layer MoS2 nanopore

    PubMed Central

    Heiranian, Mohammad; Farimani, Amir Barati; Aluru, Narayana R.

    2015-01-01

    Efficient desalination of water continues to be a problem facing the society. Advances in nanotechnology have led to the development of a variety of nanoporous membranes for water purification. Here we show, by performing molecular dynamics simulations, that a nanopore in a single-layer molybdenum disulfide can effectively reject ions and allow transport of water at a high rate. More than 88% of ions are rejected by membranes having pore areas ranging from 20 to 60 Å2. Water flux is found to be two to five orders of magnitude greater than that of other known nanoporous membranes. Pore chemistry is shown to play a significant role in modulating the water flux. Pores with only molybdenum atoms on their edges lead to higher fluxes, which are ∼70% greater than that of graphene nanopores. These observations are explained by permeation coefficients, energy barriers, water density and velocity distributions in the pores. PMID:26465062

  3. Water desalination with a single-layer MoS2 nanopore

    NASA Astrophysics Data System (ADS)

    Heiranian, Mohammad; Farimani, Amir Barati; Aluru, Narayana R.

    2015-10-01

    Efficient desalination of water continues to be a problem facing the society. Advances in nanotechnology have led to the development of a variety of nanoporous membranes for water purification. Here we show, by performing molecular dynamics simulations, that a nanopore in a single-layer molybdenum disulfide can effectively reject ions and allow transport of water at a high rate. More than 88% of ions are rejected by membranes having pore areas ranging from 20 to 60 Å2. Water flux is found to be two to five orders of magnitude greater than that of other known nanoporous membranes. Pore chemistry is shown to play a significant role in modulating the water flux. Pores with only molybdenum atoms on their edges lead to higher fluxes, which are ~70% greater than that of graphene nanopores. These observations are explained by permeation coefficients, energy barriers, water density and velocity distributions in the pores.

  4. Water desalination with a single-layer MoS2 nanopore.

    PubMed

    Heiranian, Mohammad; Farimani, Amir Barati; Aluru, Narayana R

    2015-10-14

    Efficient desalination of water continues to be a problem facing the society. Advances in nanotechnology have led to the development of a variety of nanoporous membranes for water purification. Here we show, by performing molecular dynamics simulations, that a nanopore in a single-layer molybdenum disulfide can effectively reject ions and allow transport of water at a high rate. More than 88% of ions are rejected by membranes having pore areas ranging from 20 to 60 Å(2). Water flux is found to be two to five orders of magnitude greater than that of other known nanoporous membranes. Pore chemistry is shown to play a significant role in modulating the water flux. Pores with only molybdenum atoms on their edges lead to higher fluxes, which are ∼ 70% greater than that of graphene nanopores. These observations are explained by permeation coefficients, energy barriers, water density and velocity distributions in the pores.

  5. The effects of de-icing in Helsinki urban streams, southern Finland.

    PubMed

    Ruth, O

    2003-01-01

    The environmental effects of road salt have been studied in Finland mainly in order to monitor and reduce groundwater contamination. In urban areas the road salt used for road maintenance in winter ends up in the storm water drains and receiving water bodies. We report here on water samples taken in 1998-1999 from three urban streams with catchments varying in area 1.7 to 24.4 km2 in different parts of the City of Helsinki. Despite efforts to reduce the amount of road salt, high concentrations were found in the urban stream water. Sudden variations in water quality were very marked during the spring flood period, with sodium and chloride concentrations varying over nine-fold within one day. Some 35-50% of the salt used on the roads in Helsinki passes into natural streams and from there into the sea. The significant positive correlation between NaCl and dissolved zinc in stream water was observed. The results show that it is important to monitor water quality, especially at the beginning of the spring flood period, when road salt and other contaminant levels are markedly high in urban streams.

  6. Harvesting energy from low-frequency excitations through alternate contacts between water and two dielectric materials.

    PubMed

    Yu, Jian; Ma, Enze; Ma, Tianwei

    2017-12-07

    Recent studies have demonstrated the benefits of water-dielectric interfaces in electrostatic energy harvesting. Most efforts have been focused on extracting the kinetic energy from the motions of water drops on hydrophobic surfaces, and thus, the resulting schemes inherently prefer cases where the water drops move at a high speed, or vibrate at a high frequency. Here we report a method for directly harvesting ambient mechanical energy as electric potential energy through water droplets by making alternate contacts with CYTOP and PTFE thin films. Because CYTOP and PTFE acquire significantly different surface charge densities during contact with water, such a difference can be utilized to effectively generate electricity. We demonstrate this concept using prototype devices fabricated on silicon substrates with a simple procedure. In the experiments conducted, a water drop of 400 μL alone could generate a peak open-circuit voltage of 42 V under a 0.25 Hz vibration. Under a 2.5 Hz vibration, the peak open-circuit voltage reached 115 V under an external bias of 8 V. The demonstrated efficiency is orders of magnitude higher than those of existing devices of similar dimensions.

  7. Effects of soil water table regime on tree community species richness and structure of alluvial forest fragments in Southeast Brazil.

    PubMed

    Silva, A C; Higuchi, P; van den Berg, E

    2010-08-01

    In order to determine the influence of soil water table fluctuation on tree species richness and structure of alluvial forest fragments, 24 plots were allocated in a point bar forest and 30 plots in five forest fragments located in a floodplain, in the municipality of São Sebastião da Bela Vista, Southeast Brazil, totalizing 54, 10 X 20 m, plots. The information recorded in each plot were the soil water table level, diameter at breast height (dbh), total height and botanical identity off all trees with dbh > 5 cm. The water table fluctuation was assessed through 1 m deep observation wells in each plot. Correlations analysis indicated that sites with shallower water table in the flooding plains had a low number of tree species and high tree density. Although the water table in the point bar remained below the wells during the study period, low tree species richness was observed. There are other events taking place within the point bar forest that assume a high ecological importance, such as the intensive water velocity during flooding and sedimentation processes.

  8. Literature Review on Demilitarization of Munitions: Document Prepared for the RIGHTTRAC Technology Demonstration Project

    DTIC Science & Technology

    2010-11-01

    shock, fire and impact by shrapnel or bullets but is still able to explode as intended in order to destroy its target. Two main charge explosives...involves the opening of the munitions by using a highly pressurized water jet and some abrasive material, like garnet. It was disclosed in US Patents...noise and spread of abrasive and debris around the area [23] and also avoid the production of sparks due to metal to metal contact. The water

  9. Shallow Scattering Layer (SSL): Emergence Behaviors of Coastal Macrofauna

    DTIC Science & Technology

    2003-09-30

    group ascent and descent speeds were slower than those found in a deeper water column in Puget Sound by Kringel et al. ( 2003) despite the order...instruments separated by 50 m show high coherence, but they were collected at the same water depth. Our initial data record for West Sound , Orcas Island...West Sound , Orcas Island, Washington Volume backscattering strength at 265 kHz (dB) H ei g h t ab o v e T A P S ( m ) 0 0 10 20 midnight midnight

  10. 7 CFR 993.49 - Incoming regulation.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE DRIED PRUNES PRODUCED IN CALIFORNIA... dried and cured in original natural condition, without the addition of water, and are free from active... “high moisture content prunes” are dried or dehydrated to a point where they are capable of being stored...

  11. 7 CFR 993.49 - Incoming regulation.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE DRIED PRUNES PRODUCED IN CALIFORNIA... dried and cured in original natural condition, without the addition of water, and are free from active... “high moisture content prunes” are dried or dehydrated to a point where they are capable of being stored...

  12. 7 CFR 993.49 - Incoming regulation.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE DRIED PRUNES PRODUCED IN CALIFORNIA... dried and cured in original natural condition, without the addition of water, and are free from active... “high moisture content prunes” are dried or dehydrated to a point where they are capable of being stored...

  13. 7 CFR 993.49 - Incoming regulation.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE DRIED PRUNES PRODUCED IN CALIFORNIA... dried and cured in original natural condition, without the addition of water, and are free from active... “high moisture content prunes” are dried or dehydrated to a point where they are capable of being stored...

  14. Effect of Water on Ethanol Conversion over ZnO

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

    Rahman, Muhammad Mahfuzur; Davidson, Stephen D.; Sun, Junming

    2015-10-01

    This work focuses on understanding the role of water on ethanol conversion over zinc oxide (ZnO). It was found that a competitive adsorption between ethanol and water occurs on ZnO, which leads to the blockage of the strong Lewis acid site by water on ZnO. As a result, both dehydration and dehydrogenation reactions are inhibited. However, the extent of inhibition for dehydration is orders of magnitude higher than that for dehydrogenation, leading to the shift of reaction pathway from ethanol dehydration to dehydrogenation. In the secondary reactions for acetaldehyde conversion, water inhibits the acetaldehyde aldol-condensation to crotonaldehyde, favoring the oxidationmore » of acetaldehyde to acetic acid, and then to acetone via ketonization at high temperature (i.e., 400 °C).« less

  15. Creating a testing field where delta technology and water innovations are tested and demonstrated with the help of citizen science methods

    NASA Astrophysics Data System (ADS)

    de Vries, Sandra; Rutten, Martine; de Vries, Liselotte; Anema, Kim; Klop, Tanja; Kaspersma, Judith

    2017-04-01

    In highly populated deltas, much work is to be done. Complex problems ask for new and knowledge driven solutions. Innovations in delta technology and water can bring relief to managing the water rich urban areas. Testing fields form a fundamental part of the knowledge valorisation for such innovations. In such testing fields, product development by start-ups is coupled with researchers, thus supplying new scientific insights. With the help of tests, demonstrations and large-scale applications by the end-users, these innovations find their way to the daily practices of delta management. More and more cities embrace the concept of Smart Cities to tackle the ongoing complexity of urban problems and to manage the city's assets - such as its water supply networks and other water management infrastructure. Through the use of new technologies and innovative systems, data are collected from and with citizens and devices - then processed and analysed. The information and knowledge gathered are keys to enabling a better quality of life. By testing water innovations together with citizens in order to find solutions for water management problems, not only highly spatial amounts of data are provided by and/or about these innovations, they are also improved and demonstrated to the public. A consortium consisting of a water authority, a science centre, a valorisation program and two universities have joined forces to create a testing field for delta technology and water innovations using citizen science methods. In this testing field, the use of citizen science for water technologies is researched and validated by facilitating pilot projects. In these projects, researchers, start-ups and citizens work together to find the answer to present-day water management problems. The above mentioned testing field tests the use of crowd-sourcing data as for example hydrological model inputs, or to validate remote sensing applications, or improve water management decisions. Currently the testing field starts two pilot projects concerning (1) the validation of green measures used for water storage in order to better quantify their worth, and (2) the collection of water quality data in a polder polluted by horticulture in such manner that water management and awareness are improved.

  16. On the Role of Water Models in Quantifying the Binding Free Energy of Highly Conserved Water Molecules in Proteins: The Case of Concanavalin A.

    PubMed

    Fadda, Elisa; Woods, Robert J

    2011-10-11

    The ability of ligands to displace conserved water molecules in protein binding sites is of significant interest in drug design and is particularly pertinent in the case of glycomimetic drugs. This concept was explored in previous work [ Clarke et al. J. Am. Chem. Soc. 2001 , 123 , 12238 - 12247 and Kadirvelraj et al. J. Am. Chem. Soc. 2008 , 130 , 16933 - 16942 ] for a highly conserved water molecule located in the binding site of the prototypic carbohydrate-binding protein Concanavalin A (Con A). A synthetic ligand was designed with the aim of displacing such water. While the synthetic ligand bound to Con A in an analogous manner to that of the natural ligand, crystallographic analysis demonstrated that it did not displace the conserved water. In order to quantify the affinity of this particular water for the Con A surface, we report here the calculated standard binding free energy for this water in both ligand-bound and free Con A, employing three popular water models: TIP3P, TIP4P, and TIP5P. Although each model was developed to perform well in simulations of bulk-phase water, the computed binding energies for the isolated water molecule displayed a high sensitivity to the model. Both molecular dynamics simulation and free energy results indicate that the choice of water model may greatly influence the characterization of surface water molecules as conserved (TIP5P) or not (TIP3P) in protein binding sites, an observation of considerable significance to rational drug design. Structural and theoretical aspects at the basis of the different behaviors are identified and discussed.

  17. Methane fluxes from tropical coastal lagoons surrounded bymangroves, Yucatán, Mexico

    USGS Publications Warehouse

    Chuang, Pei-Chuan; Young, Megan B.; Dale, Andrew W.; Miller, Laurence G.; Herrera-Silveira, Jorge A; Paytan, Adina

    2017-01-01

    Methane concentrations in the water column and emissions to the atmosphere were determined for three tropical coastal lagoons surrounded by mangrove forests on the Yucatán Peninsula, Mexico. Surface water dissolved methane was sampled at different seasons over a period of 2 years in areas representing a wide range of salinities and anthropogenic impacts. The highest surface water methane concentrations (up to 8378 nM) were measured in a polluted canal associated with Terminos Lagoon. In Chelem Lagoon, methane concentrations were typically lower, except in the polluted harbor area (1796 nM). In the relatively pristine Celestún Lagoon, surface water methane concentrations ranged from 41 to 2551 nM. Methane concentrations were negatively correlated with salinity in Celestún, while in Chelem and Terminos high methane concentrations were associated with areas of known pollution inputs, irrespective of salinity. The diffusive methane flux from surface lagoon water to the atmosphere ranged from 0.0023 to 15 mmol CH4 m−2 d−1. Flux chamber measurements revealed that direct methane release as ebullition was up to 3 orders of magnitude greater than measured diffusive flux. Coastal mangrove lagoons may therefore be an important natural source of methane to the atmosphere despite their relatively high salinity. Pollution inputs are likely to substantially enhance this flux. Additional statistically rigorous data collected globally are needed to better consider methane fluxes from mangrove-surrounded coastal areas in response to sea level changes and anthropogenic pollution in order to refine projections of future atmospheric methane budgets.

  18. Methane fluxes from tropical coastal lagoons surrounded by mangroves, Yucatán, Mexico

    NASA Astrophysics Data System (ADS)

    Chuang, P.-C.; Young, M. B.; Dale, A. W.; Miller, L. G.; Herrera-Silveira, J. A.; Paytan, A.

    2017-05-01

    Methane concentrations in the water column and emissions to the atmosphere were determined for three tropical coastal lagoons surrounded by mangrove forests on the Yucatán Peninsula, Mexico. Surface water dissolved methane was sampled at different seasons over a period of 2 years in areas representing a wide range of salinities and anthropogenic impacts. The highest surface water methane concentrations (up to 8378 nM) were measured in a polluted canal associated with Terminos Lagoon. In Chelem Lagoon, methane concentrations were typically lower, except in the polluted harbor area (1796 nM). In the relatively pristine Celestún Lagoon, surface water methane concentrations ranged from 41 to 2551 nM. Methane concentrations were negatively correlated with salinity in Celestún, while in Chelem and Terminos high methane concentrations were associated with areas of known pollution inputs, irrespective of salinity. The diffusive methane flux from surface lagoon water to the atmosphere ranged from 0.0023 to 15 mmol CH4 m-2 d-1. Flux chamber measurements revealed that direct methane release as ebullition was up to 3 orders of magnitude greater than measured diffusive flux. Coastal mangrove lagoons may therefore be an important natural source of methane to the atmosphere despite their relatively high salinity. Pollution inputs are likely to substantially enhance this flux. Additional statistically rigorous data collected globally are needed to better consider methane fluxes from mangrove-surrounded coastal areas in response to sea level changes and anthropogenic pollution in order to refine projections of future atmospheric methane budgets.

  19. Effects on environment and agriculture of geothermal wastewater and boron pollution in great Menderes basin.

    PubMed

    Koç, Cengiz

    2007-02-01

    Boron toxicity is an important disorder that can be limit plant growth on soils of arid and semi arid environments through the world. High concentrations of Boron may occur naturally in the soil or in groundwater, or be added to the soil from mining, fertilizers, or irrigation water. Off all the potential resources, irrigation water is the most important contributor to high levels of soil boron, boron is often found in high concentrations in association with saline soil and saline well water. Although of considerable agronomic importance, our understanding of Boron toxicity is rather fragment and limited. In this study, Boron content of Great Menderes River and Basin was researched. Great Menderes Basin is one of the consequence basins having agricultural potential, aspect of water and soil resources in Turkey. Great Menderes River, water resource of the basin was to be polluted by geothermal wastewater and thermal springs including Boron element. Great Menderes Basin has abundant geothermal water resources which contain high amounts of Boron and these ground water are brought to surface and used for various purposes such as power generation, heating or thermal spring and than discharged to Great Menderes River. In order to prevent Boron pollution and hence unproductively in soils, it is necessary not to discharged water with Boron to irrigation water. According to results, it was obtained that Boron content of River was as high in particular Upper Basin where there was a ground thermal water reservoir. Boron has been accumulated more than plant requirement in this area irrigated by this water. Boron content of River was relatively low in rainy months and irrigation season while it was high in dry season. Boron concentration in the River was to decrease from upstream to downstream. If it is no taken measure presently, about 130,000 ha irrigation areas which was constructed irrigation scheme in the Great Menderes basin will expose the Boron pollution and salinity. Even though Boron concentration of river water is under 0.5 ppm limit value, Boron element will store in basin soils, decrease in crop yields, and occur problematic soils in basin.

  20. [Effects of supplemental irrigation based on the measurement of moisture content in different soil layers on the water consumption characteristics and grain yield of winter wheat].

    PubMed

    Yi, Li-Pan; Yu, Zhen-Wen; Zhang, Yong-Li; Wang, Dong; Shi, Yu; Zhao, Jun-Ye

    2013-05-01

    In 2010-2011, a field experiment with high-yielding winter wheat cultivar Jimai 22 was conducted to study the effects of supplemental irrigation based on the measurement of moisture content in different soil layers on the water consumption characteristics and grain yield of winter wheat. Four soil layers (0-20 cm, W1; 0-40 cm, W2; 0-60 cm, W3; and 0-140 cm, W4) were designed to make the supplemental irrigation at wintering stage (target soil relative moisture content = 75%), jointing stage (target soil relative moisture content = 70%), and anthesis stage (target soil relative moisture content = 70%), taking no irrigation (W0) during the whole growth season as the control. At the wintering, jointing, and anthesis stages, the required irrigation amount followed the order of W3 > W2 > W1. Treatment W4 required smaller irrigation amount at wintering and jointing stages, but significantly higher one at anthesis stage than the other treatments. The proportion of the irrigation amount relative to the total water consumption over the entire growth season followed the sequence of W4, W3 > W2 > W1. By contrast, the proportion of soil water consumption relative to the total water consumption followed the trend of W1 > W2 > W3 > W4. With the increase of the test soil depths, the soil water utilization ratio decreased. The water consumption in 80-140 cm and 160-200 cm soil layers was significantly higher in W2 than in W3 and W4. The required total irrigation amount was in the order of W3 > W4 > W2 > W1, the grain yield was in the order of W2, W3, W4 > W1 > W0, and the water use efficiency followed the order of W2, W4 > W0, W1 > W3. To consider the irrigation amount, grain yield, and water use efficiency comprehensively, treatment W2 under our experimental condition could be the optimal treatment, i. e., the required amount of supplemental irrigation based on the measurement of the moisture content in 0-40 cm soil layer should be feasible for the local winter wheat production.

  1. Computational methods and traveling wave solutions for the fourth-order nonlinear Ablowitz-Kaup-Newell-Segur water wave dynamical equation via two methods and its applications

    NASA Astrophysics Data System (ADS)

    Ali, Asghar; Seadawy, Aly R.; Lu, Dianchen

    2018-05-01

    The aim of this article is to construct some new traveling wave solutions and investigate localized structures for fourth-order nonlinear Ablowitz-Kaup-Newell-Segur (AKNS) water wave dynamical equation. The simple equation method (SEM) and the modified simple equation method (MSEM) are applied in this paper to construct the analytical traveling wave solutions of AKNS equation. The different waves solutions are derived by assigning special values to the parameters. The obtained results have their importance in the field of physics and other areas of applied sciences. All the solutions are also graphically represented. The constructed results are often helpful for studying several new localized structures and the waves interaction in the high-dimensional models.

  2. Atomic force microscopy of hydrated phosphatidylethanolamine bilayers.

    PubMed Central

    Zasadzinski, J A; Helm, C A; Longo, M L; Weisenhorn, A L; Gould, S A; Hansma, P K

    1991-01-01

    We present images of the polar or headgroup regions of bilayers of dimyristoyl-phosphatidylethanolamine (DMPE), deposited by Langmuir-Blodgett deposition onto mica substrates at high surface pressures and imaged under water at room temperature with the optical lever atomic force microscope. The lattice structure of DMPE is visualized with sufficient resolution that the location of individual headgroups can be determined. The forces are sufficiently small that the same area can be repeatedly imaged with a minimum of damage. The DMPE molecules in the bilayer appear to have relatively good long-range orientational order, but rather short-range and poor positional order. These results are in good agreement with x-ray measurements of unsupported lipid monolayers on the water surface, and with electron diffraction of adsorbed monolayers. Images FIGURE 1 FIGURE 2 PMID:2049529

  3. Graphene oxide-based efficient and scalable solar desalination under one sun with a confined 2D water path

    PubMed Central

    Li, Xiuqiang; Xu, Weichao; Tang, Mingyao; Zhou, Lin; Zhu, Bin; Zhu, Shining; Zhu, Jia

    2016-01-01

    Because it is able to produce desalinated water directly using solar energy with minimum carbon footprint, solar steam generation and desalination is considered one of the most important technologies to address the increasingly pressing global water scarcity. Despite tremendous progress in the past few years, efficient solar steam generation and desalination can only be achieved for rather limited water quantity with the assistance of concentrators and thermal insulation, not feasible for large-scale applications. The fundamental paradox is that the conventional design of direct absorber−bulk water contact ensures efficient energy transfer and water supply but also has intrinsic thermal loss through bulk water. Here, enabled by a confined 2D water path, we report an efficient (80% under one-sun illumination) and effective (four orders salinity decrement) solar desalination device. More strikingly, because of minimized heat loss, high efficiency of solar desalination is independent of the water quantity and can be maintained without thermal insulation of the container. A foldable graphene oxide film, fabricated by a scalable process, serves as efficient solar absorbers (>94%), vapor channels, and thermal insulators. With unique structure designs fabricated by scalable processes and high and stable efficiency achieved under normal solar illumination independent of water quantity without any supporting systems, our device represents a concrete step for solar desalination to emerge as a complementary portable and personalized clean water solution. PMID:27872280

  4. 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.

  5. Graphene oxide-based efficient and scalable solar desalination under one sun with a confined 2D water path.

    PubMed

    Li, Xiuqiang; Xu, Weichao; Tang, Mingyao; Zhou, Lin; Zhu, Bin; Zhu, Shining; Zhu, Jia

    2016-12-06

    Because it is able to produce desalinated water directly using solar energy with minimum carbon footprint, solar steam generation and desalination is considered one of the most important technologies to address the increasingly pressing global water scarcity. Despite tremendous progress in the past few years, efficient solar steam generation and desalination can only be achieved for rather limited water quantity with the assistance of concentrators and thermal insulation, not feasible for large-scale applications. The fundamental paradox is that the conventional design of direct absorber-bulk water contact ensures efficient energy transfer and water supply but also has intrinsic thermal loss through bulk water. Here, enabled by a confined 2D water path, we report an efficient (80% under one-sun illumination) and effective (four orders salinity decrement) solar desalination device. More strikingly, because of minimized heat loss, high efficiency of solar desalination is independent of the water quantity and can be maintained without thermal insulation of the container. A foldable graphene oxide film, fabricated by a scalable process, serves as efficient solar absorbers (>94%), vapor channels, and thermal insulators. With unique structure designs fabricated by scalable processes and high and stable efficiency achieved under normal solar illumination independent of water quantity without any supporting systems, our device represents a concrete step for solar desalination to emerge as a complementary portable and personalized clean water solution.

  6. Ice-nucleating bacteria control the order and dynamics of interfacial water

    DOE PAGES

    Pandey, Ravindra; Usui, Kota; Livingstone, Ruth A.; ...

    2016-04-22

    Ice-nucleating organisms play important roles in the environment. With their ability to induce ice formation at temperatures just below the ice melting point, bacteria such as Pseudomonas syringae attack plants through frost damage using specialized ice-nucleating proteins. Besides the impact on agriculture and microbial ecology, airborne P. syringae can affect atmospheric glaciation processes, with consequences for cloud evolution, precipitation, and climate. Biogenic ice nucleation is also relevant for artificial snow production and for biomimetic materials for controlled interfacial freezing. We use interface-specific sum frequency generation (SFG) spectroscopy to show that hydrogen bonding at the water-bacteria contact imposes structural ordering onmore » the adjacent water network. Experimental SFG data and molecular dynamics simulations demonstrate that ice active sites within P. syringae feature unique hydrophilic-hydrophobic patterns to enhance ice nucleation. Finally, the freezing transition is further facilitated by the highly effective removal of latent heat from the nucleation site, as apparent from time-resolved SFG spectroscopy.« less

  7. The High-Resolution Structure of Activated Opsin Reveals a Conserved Solvent Network in the Transmembrane Region Essential for Activation.

    PubMed

    Blankenship, Elise; Vahedi-Faridi, Ardeschir; Lodowski, David T

    2015-12-01

    Rhodopsin, a light-activated G protein coupled receptor (GPCR), has been the subject of numerous biochemical and structural investigations, serving as a model receptor for GPCRs and their activation. We present the 2.3-Å resolution structure of native source rhodopsin stabilized in a conformation competent for G protein binding. An extensive water-mediated hydrogen bond network linking the chromophore binding site to the site of G protein binding is observed, providing connections to conserved motifs essential for GPCR activation. Comparison of this extensive solvent-mediated hydrogen-bonding network with the positions of ordered solvent in earlier crystallographic structures of rhodopsin photointermediates reveals both static structural and dynamic functional water-protein interactions present during the activation process. When considered along with observations that solvent occupies similar positions in the structures of other GPCRs, these analyses strongly support an integral role for this dynamic ordered water network in both rhodopsin and GPCR activation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Ice-nucleating bacteria control the order and dynamics of interfacial water

    PubMed Central

    Pandey, Ravindra; Usui, Kota; Livingstone, Ruth A.; Fischer, Sean A.; Pfaendtner, Jim; Backus, Ellen H. G.; Nagata, Yuki; Fröhlich-Nowoisky, Janine; Schmüser, Lars; Mauri, Sergio; Scheel, Jan F.; Knopf, Daniel A.; Pöschl, Ulrich; Bonn, Mischa; Weidner, Tobias

    2016-01-01

    Ice-nucleating organisms play important roles in the environment. With their ability to induce ice formation at temperatures just below the ice melting point, bacteria such as Pseudomonas syringae attack plants through frost damage using specialized ice-nucleating proteins. Besides the impact on agriculture and microbial ecology, airborne P. syringae can affect atmospheric glaciation processes, with consequences for cloud evolution, precipitation, and climate. Biogenic ice nucleation is also relevant for artificial snow production and for biomimetic materials for controlled interfacial freezing. We use interface-specific sum frequency generation (SFG) spectroscopy to show that hydrogen bonding at the water-bacteria contact imposes structural ordering on the adjacent water network. Experimental SFG data and molecular dynamics simulations demonstrate that ice-active sites within P. syringae feature unique hydrophilic-hydrophobic patterns to enhance ice nucleation. The freezing transition is further facilitated by the highly effective removal of latent heat from the nucleation site, as apparent from time-resolved SFG spectroscopy. PMID:27152346

  9. Optimization of the Working Cycle for an Underwater Propulsion System Based on Aluminium-Water Combustion

    NASA Astrophysics Data System (ADS)

    Chen, Xianhe; Xia, Zhixun; Huang, Liya; Hu, Jianxin

    2017-05-01

    The working cycle of a novel underwater propulsion system based on aluminium combustion with water is researched in order to evaluate the best performance. The system exploits the exothermic reaction between aluminium and water which will produce high temperature, pressure steam and hydrogen mixture that can be used to drive turbine to generate power. Several new system configurations corresponding to different working cycles are investigated, and their performance parameters in terms of net power, energy density and global efficiency are discussed. The results of the system simulation show that using the recirculation steam rather than hydrogen as the carrier gas, the system net power, energy density and efficiency of the system are greatly increased compared, however the system performance is close either using adiabatic compression or isothermal compression. And if an evaporator component is added into system in order to take full use of the solid product heat, the system performance will be improved.

  10. On-tap passive enrichment, a new way to investigate off-flavor episodes in drinking water.

    PubMed

    Tondelier, Christophe; Thouvenot, Thomas; Genin, Arnaud; Benanou, David

    2009-04-03

    Because taste and odor events in drinking water are often fleeting and unpredictable phenomena, an innovative enrichment sampler has been developed to trap off-flavor compounds directly at the consumer's tap. The ARISTOT (Advanced Relevant Investigation Sampler for Taste & Odor at Tap) consists of a tap adapter in which seven polydimethylsiloxane (PDMS) coated stir bars are placed, allowing the stir bar sorptive extraction (SBSE) of organic compounds during each tap opening. In order to study the efficiency of ARISTOT, a private network pilot unit has been constructed in our laboratory, equipped with four faucets in parallel, solenoid valves for an automation of the system and a mixing chamber to spike drinking water with odorous compounds in order to have homogenously smelling water at each tap. After enrichment, the stir bars are taken out, in-line thermo-desorbed and analyzed by gas chromatography coupled with a mass spectrometer. The results showed the high sensitivity of ARISTOT, which was able to quickly monitor odorous compounds at the sub ng/L level. A "multishot" method was developed to analyze chemicals concentrated on the seven stir bars in only one chromatographic run, thereby increasing the sensitivity of the system. Higher enrichment factors were obtained under low water flow rates or by using longer stir bars and/or stir bars with a higher PDMS film thickness. No significant loss of extracted compounds was reported for flow rates between 2 and 4L/min. This allowed us to spike the stir bars with an internal standard prior to sampling in order to monitor the analytical variations. It was also observed that hot water increases the loss of enriched solutes but the quantification can be corrected by internal standard addition.

  11. Grid Effect on Spherical Shallow Water Jets Using Continuous and Discontinuous Galerkin Methods

    DTIC Science & Technology

    2013-01-01

    The high-order Legendre -Gauss-Lobatto (LGL) points are added to the linear grid by projecting the linear elements onto the auxiliary gnomonic space...mapping, the triangles are subdivided into smaller ones by a Lagrange polynomial of order nI . The number of quadrilateral elements and grid points of...of the acceleration of gravity and the vertical height of the fluid), ν∇2 is the artificial viscosity term of viscous coefficient ν = 1× 105 m2 s−1

  12. Diving depths

    NASA Astrophysics Data System (ADS)

    Clanet, Christophe; Guillet, Thibault; Coux, Martin; Quéré, David

    2017-11-01

    Many seabirds (gannets, pelicans, gulls, albatrosses) dive into water at high speeds (25 m/s) in order to capture underwater preys. Diving depths of 20 body lengths are reported in the literature. This value is much larger than the one achieved by men, which is typically of the order of 3. We study this difference by comparing the vertical impact of slender vs bluff bodies. We quantify the influence of wetting and of the geometry on the trajectory and discuss the different laws that govern the diving depth.

  13. Effect of electrolyzed high-pH alkaline water on blood viscosity in healthy adults.

    PubMed

    Weidman, Joseph; Holsworth, Ralph E; Brossman, Bradley; Cho, Daniel J; St Cyr, John; Fridman, Gregory

    2016-01-01

    Previous research has shown fluid replacement beverages ingested after exercise can affect hydration biomarkers. No specific hydration marker is universally accepted as an ideal rehydration parameter following strenuous exercise. Currently, changes in body mass are used as a parameter during post-exercise hydration. Additional parameters are needed to fully appreciate and better understand rehydration following strenuous exercise. This randomized, double-blind, parallel-arm trial assessed the effect of high-pH water on four biomarkers after exercise-induced dehydration. One hundred healthy adults (50 M/50 F, 31 ± 6 years of age) were enrolled at a single clinical research center in Camden, NJ and completed this study with no adverse events. All individuals exercised in a warm environment (30 °C, 70% relative humidity) until their weight was reduced by a normally accepted level of 2.0 ± 0.2% due to perspiration, reflecting the effects of exercise in producing mild dehydration. Participants were randomized to rehydrate with an electrolyzed, high-pH (alkaline) water or standard water of equal volume (2% body weight) and assessed for an additional 2-h recovery period following exercise in order to assess any potential variations in measured parameters. The following biomarkers were assessed at baseline and during their recovery period: blood viscosity at high and low shear rates, plasma osmolality, bioimpedance, and body mass, as well as monitoring vital signs. Furthermore, a mixed model analysis was performed for additional validation. After exercise-induced dehydration, consumption of the electrolyzed, high-pH water reduced high-shear viscosity by an average of 6.30% compared to 3.36% with standard purified water ( p  = 0.03). Other measured biomarkers (plasma osmolality, bioimpedance, and body mass change) revealed no significant difference between the two types of water for rehydration. However, a mixed model analysis validated the effect of high-pH water on high-shear viscosity when compared to standard purified water ( p  = 0.0213) after controlling for covariates such as age and baseline values. A significant difference in whole blood viscosity was detected in this study when assessing a high-pH, electrolyte water versus an acceptable standard purified water during the recovery phase following strenuous exercise-induced dehydration.

  14. Effect of moderate high temperature on the vegetative growth and potassium allocation in olive plants.

    PubMed

    Benlloch-González, María; Quintero, José Manuel; Suárez, María Paz; Sánchez-Lucas, Rosa; Fernández-Escobar, Ricardo; Benlloch, Manuel

    2016-12-01

    There is little information about the prolonged effect of a moderately high temperature on the growth of olive (Olea europaea L.). It has been suggested that when the temperature of the air rises above 35°C the shoot growth of olive is inhibited while there is any reference on how growth is affected when the soil is warmed. In order to examine these effects, mist-cuttings and young plants generated from seeds were grown under moderate high temperature (37°C) for 64 and 42days respectively. In our study, plant dry matter accumulation was reduced when the temperature of both the air and the root medium was moderately high. However, when the temperature of the root medium was 25°C, the inhibitory effect of air high temperature on plant growth was not observed. The exposure of both the aerial part and the root to moderate high temperature also reduced the accumulation of K + in the stem and the root, the water use efficiency and leaf relative water content. However, when only the aerial part was exposed to moderate high temperature, the accumulation of K + in the stem, the water use efficiency and leaf relative water content were not modified. The results from this study suggest that the olive is very efficient in regulating the water and potassium transport through the plant when only the atmosphere surrounding the aerial part is warmed up. However, an increase in the soil temperature decrease root K + uptake and its transport to the aerial parts resulting in a reduction in shoot water status and growth. Copyright © 2016 Elsevier GmbH. All rights reserved.

  15. Predicting glass-to-glass and liquid-to-liquid phase transitions in supercooled water using classical nucleation theory

    NASA Astrophysics Data System (ADS)

    Tournier, Robert F.

    2018-01-01

    Glass-to-glass and liquid-to-liquid phase transitions are observed in bulk and confined water, with or without applied pressure. They result from the competition of two liquid phases separated by an enthalpy difference depending on temperature. The classical nucleation equation of these phases is completed by this quantity existing at all temperatures, a pressure contribution, and an enthalpy excess. This equation leads to two homogeneous nucleation temperatures in each liquid phase; the first one (Tn- below Tm) being the formation temperature of an "ordered" liquid phase and the second one corresponding to the overheating temperature (Tn+ above Tm). Thermodynamic properties, double glass transition temperatures, sharp enthalpy and volume changes are predicted in agreement with experimental results. The first-order transition line at TLL = 0.833 × Tm between fragile and strong liquids joins two critical points. Glass phase above Tg becomes "ordered" liquid phase disappearing at TLL at low pressure and at Tn+ = 1.302 × Tm at high pressure.

  16. Photoelectrodes based upon Mo:BiVO4 inverse opals for photoelectrochemical water splitting.

    PubMed

    Zhou, Min; Bao, Jian; Xu, Yang; Zhang, Jiajia; Xie, Junfeng; Guan, Meili; Wang, Chengliang; Wen, Liaoyong; Lei, Yong; Xie, Yi

    2014-07-22

    BiVO4 has been regarded as a promising material for photoelectrochemical water splitting, but it suffers from a major challenge on charge collection and utilization. In order to meet this challenge, we design a nanoengineered three-dimensional (3D) ordered macro-mesoporous architecture (a kind of inverse opal) of Mo:BiVO4 through a controllable colloidal crystal template method with the help of a sandwich solution infiltration method and adjustable post-heating time. Within expectation, a superior photocurrent density is achieved in return for this design. This enhancement originates primarily from effective charge collection and utilization according to the analysis of electrochemical impedance spectroscopy and so on. All the results highlight the great significance of the 3D ordered macro-mesoporous architecture as a promising photoelectrode model for the application in solar conversion. The cooperating amplification effects of nanoengineering from composition regulation and morphology innovation are helpful for creating more purpose-designed photoelectrodes with highly efficient performance.

  17. How ions affect the structure of water.

    PubMed

    Hribar, Barbara; Southall, Noel T; Vlachy, Vojko; Dill, Ken A

    2002-10-16

    We model ion solvation in water. We use the MB model of water, a simple two-dimensional statistical mechanical model in which waters are represented as Lennard-Jones disks having Gaussian hydrogen-bonding arms. We introduce a charge dipole into MB waters. We perform (NPT) Monte Carlo simulations to explore how water molecules are organized around ions and around nonpolar solutes in salt solutions. The model gives good qualitative agreement with experiments, including Jones-Dole viscosity B coefficients, Samoilov and Hirata ion hydration activation energies, ion solvation thermodynamics, and Setschenow coefficients for Hofmeister series ions, which describe the salt concentration dependence of the solubilities of hydrophobic solutes. The two main ideas captured here are (1) that charge densities govern the interactions of ions with water, and (2) that a balance of forces determines water structure: electrostatics (water's dipole interacting with ions) and hydrogen bonding (water interacting with neighboring waters). Small ions (kosmotropes) have high charge densities so they cause strong electrostatic ordering of nearby waters, breaking hydrogen bonds. In contrast, large ions (chaotropes) have low charge densities, and surrounding water molecules are largely hydrogen bonded.

  18. Fatigue Crack Propagation from Notched Specimens of 304 SS in elevated Temperature Aqueous Environment

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

    Wire, G. L.; Mills, W. J.

    2002-08-01

    Fatigue crack propagation (FCP) rates for 304 stainless steel (304SS) were determined in 24 degree C and 288 degree C air and 288 degree C water using double-edged notch (DEN) specimens of 304 stainless steel (304 SS). Test performed at matched loading conditions in air and water at 288 degree C with 20-6- cc h[sub]2/kg h[sub]2O provided a direct comparison of the relative crack growth rates in air and water over a wide range of crack growth rates. The DEN crack extension ranged from short cracks (0.03-0.25 mm) to long cracks up to 4.06 mm, which are consistent with conventionalmore » deep crack tests. Crack growth rates of 304 SS in water were about 12 times the air rate. This 12X environmental enhancement persisted to crack extensions up to 4.06 mm, far outside the range associated with short crack effects. The large environmental degradation for 304 SS crack growth is consistent with the strong reduction of fatigue life in high hydrogen water. Further, very similar environmental effects w ere reported in fatigue crack growth tests in hydrogen water chemistry (HWC). Most literature data in high hydrogen water show only a mild environmental effect for 304 SS, of order 2.5 times air or less, but the tests were predominantly performed at high cyclic stress intensity or equivalently, high air rates. The environmental effect in low oxygen environments at low stress intensity depends strongly on both the stress ratio, R, and the load rise time, T[sub]r, as recently reported for austenitic stainless steel in BWR water. Fractography was performed for both tests in air and water. At 288 degree C in water, the fracture surfaces were crisply faceted with a crystallographic appearance, and showed striations under high magnification. The cleavage-like facets on the fracture surfaces suggest that hydrogen embrittlement is the primary cause of accelerated cracking.« less

  19. Water Ordering Controls the Dynamic Equilibrium of Micelle-Fiber Formation in Self-Assembly of Peptide Amphiphiles

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

    Deshmukh, Sanket; Solomon, Lee A.; Kamath, Ganesh

    Understanding the role of water in governing the kinetics of the self-assembly processes of amphiphilic peptides has still remained elusive. Here, using a multi-stage atomistic-coarse-grained approach, complemented by circular dichroism/infra-red spectroscopy and dynamic light scattering experiments, we highlight the dual nature of water in dictating the mechanism and dynamics of self-assembly of peptide amphiphiles (PAs). Our computational study shows that (i) Water cage formation and breakage near the hydrophobic groups controls the fusion dynamics and aggregation of PAs in the micellar stage, and (ii) Enhanced structural ordering of vicinal water near the hydrophilic amino acids shifts the equilibrium towards themore » fiber phase and stimulates structure and order in the PAs when they assemble into a hexagonal nanofiber architecture. Finally, spectroscopy and microscopy studies authenticate our computational observation that water ordering near the PAs increases with increase in time. The measured infra-red O-H bond stretch frequency reminiscent of ice-like suggests that the solvated water becomes increasingly solid-like with increased structural order in the assembled peptide network – thus shedding light on the role of water in a self-assembly process.« less

  20. Water Ordering Controls the Dynamic Equilibrium of Micelle-Fiber Formation in Self-Assembly of Peptide Amphiphiles

    DOE PAGES

    Deshmukh, Sanket; Solomon, Lee A.; Kamath, Ganesh; ...

    2016-08-24

    Understanding the role of water in governing the kinetics of the self-assembly processes of amphiphilic peptides has still remained elusive. Here, using a multi-stage atomistic-coarse-grained approach, complemented by circular dichroism/infra-red spectroscopy and dynamic light scattering experiments, we highlight the dual nature of water in dictating the mechanism and dynamics of self-assembly of peptide amphiphiles (PAs). Our computational study shows that (i) Water cage formation and breakage near the hydrophobic groups controls the fusion dynamics and aggregation of PAs in the micellar stage, and (ii) Enhanced structural ordering of vicinal water near the hydrophilic amino acids shifts the equilibrium towards themore » fiber phase and stimulates structure and order in the PAs when they assemble into a hexagonal nanofiber architecture. Finally, spectroscopy and microscopy studies authenticate our computational observation that water ordering near the PAs increases with increase in time. The measured infra-red O-H bond stretch frequency reminiscent of ice-like suggests that the solvated water becomes increasingly solid-like with increased structural order in the assembled peptide network – thus shedding light on the role of water in a self-assembly process.« less

  1. 43 CFR 417.3 - Notice of recommendations and determinations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... RECLAMATION, DEPARTMENT OF THE INTERIOR PROCEDURAL METHODS FOR IMPLEMENTING COLORADO RIVER WATER CONSERVATION... raised, cropping practices, the type of irrigation system in use, the condition of water carriage and distribution facilities, record of water orders, and rejections of ordered water, general operating practices...

  2. 43 CFR 417.3 - Notice of recommendations and determinations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... RECLAMATION, DEPARTMENT OF THE INTERIOR PROCEDURAL METHODS FOR IMPLEMENTING COLORADO RIVER WATER CONSERVATION... raised, cropping practices, the type of irrigation system in use, the condition of water carriage and distribution facilities, record of water orders, and rejections of ordered water, general operating practices...

  3. 43 CFR 417.3 - Notice of recommendations and determinations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... RECLAMATION, DEPARTMENT OF THE INTERIOR PROCEDURAL METHODS FOR IMPLEMENTING COLORADO RIVER WATER CONSERVATION... raised, cropping practices, the type of irrigation system in use, the condition of water carriage and distribution facilities, record of water orders, and rejections of ordered water, general operating practices...

  4. Embedded optical fibers for PDV measurements in shock-loaded, light and heavy water

    NASA Astrophysics Data System (ADS)

    Mercier, Patrick; Benier, Jacky; Frugier, Pierre-Antoine; Debruyne, Michel; Bolis, Cyril

    2011-06-01

    In order to study the shock-detonation transition, it is necessary to characterize the shock loading of a high explosive plane wave generator into a nitromethane cell. To eliminate the reactive behaviour, we replace the nitromethane by an inert liquid compound. Light water has been first employed; eventually heavy water has been chosen for its better infrared spectral properties. We present the PDV results of different submerged embedded optical fibers which sense the medium with two different approaches: a non-intrusive optical observation of phenomena coming in front of them (interface, shock wave) followed by the mechanical interaction with the shock wave.

  5. Combining Empirical Relationships with Data Based Mechanistic Modeling to Inform Solute Tracer Investigations across Stream Orders

    NASA Astrophysics Data System (ADS)

    Herrington, C.; Gonzalez-Pinzon, R.; Covino, T. P.; Mortensen, J.

    2015-12-01

    Solute transport studies in streams and rivers often begin with the introduction of conservative and reactive tracers into the water column. Information on the transport of these substances is then captured within tracer breakthrough curves (BTCs) and used to estimate, for instance, travel times and dissolved nutrient and carbon dynamics. Traditionally, these investigations have been limited to systems with small discharges (< 200 L/s) and with small reach lengths (< 500 m), partly due to the need for a priori information of the reach's hydraulic characteristics (e.g., channel geometry, resistance and dispersion coefficients) to predict arrival times, times to peak concentrations of the solute and mean travel times. Current techniques to acquire these channel characteristics through preliminary tracer injections become cost prohibitive at higher stream orders and the use of semi-continuous water quality sensors for collecting real-time information may be affected from erroneous readings that are masked by high turbidity (e.g., nitrate signals with SUNA instruments or fluorescence measures) and/or high total dissolved solids (e.g., making prohibitively expensive the use of salt tracers such as NaCl) in larger systems. Additionally, a successful time-of-travel study is valuable for only a single discharge and river stage. We have developed a method to predict tracer BTCs to inform sampling frequencies at small and large stream orders using empirical relationships developed from multiple tracer injections spanning several orders of magnitude in discharge and reach length. This method was successfully tested in 1st to 8th order systems along the Middle Rio Grande River Basin in New Mexico, USA.

  6. 32 CFR 761.3 - Authority.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...; 3 CFR, 1943 Cum. Supp., p. 504). (iv) Johnston Island Naval Defensive Sea Area; Johnston Island... territorial waters: (1) Johnston Island—Executive Order 6935 of December 29, 1934 as amended by Executive... (Kwajalein Atoll) and of the Defense Nuclear Agency (Eniwetok Atoll) see § 761.4) is controlled by the High...

  7. 32 CFR 761.3 - Authority.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...; 3 CFR, 1943 Cum. Supp., p. 504). (iv) Johnston Island Naval Defensive Sea Area; Johnston Island... territorial waters: (1) Johnston Island—Executive Order 6935 of December 29, 1934 as amended by Executive... (Kwajalein Atoll) and of the Defense Nuclear Agency (Eniwetok Atoll) see § 761.4) is controlled by the High...

  8. 32 CFR 761.3 - Authority.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...; 3 CFR, 1943 Cum. Supp., p. 504). (iv) Johnston Island Naval Defensive Sea Area; Johnston Island... territorial waters: (1) Johnston Island—Executive Order 6935 of December 29, 1934 as amended by Executive... (Kwajalein Atoll) and of the Defense Nuclear Agency (Eniwetok Atoll) see § 761.4) is controlled by the High...

  9. 32 CFR 761.3 - Authority.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...; 3 CFR, 1943 Cum. Supp., p. 504). (iv) Johnston Island Naval Defensive Sea Area; Johnston Island... territorial waters: (1) Johnston Island—Executive Order 6935 of December 29, 1934 as amended by Executive... (Kwajalein Atoll) and of the Defense Nuclear Agency (Eniwetok Atoll) see § 761.4) is controlled by the High...

  10. 32 CFR 761.3 - Authority.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...; 3 CFR, 1943 Cum. Supp., p. 504). (iv) Johnston Island Naval Defensive Sea Area; Johnston Island... territorial waters: (1) Johnston Island—Executive Order 6935 of December 29, 1934 as amended by Executive... (Kwajalein Atoll) and of the Defense Nuclear Agency (Eniwetok Atoll) see § 761.4) is controlled by the High...

  11. New methods for modeling stream temperature using high resolution LiDAR, solar radiation analysis and flow accumulated values

    EPA Science Inventory

    In-stream temperature directly effects a variety of biotic organisms, communities and processes. Changes in stream temperature can render formally suitable habitat unsuitable for aquatic organisms, particularly native cold water species that are not able to adjust. In order to an...

  12. UV Influence on the Re-Growth of Pathogens in Cow Fecal Extract

    EPA Science Inventory

    The health risks pathogens pose to water and food resources are highly dependent on their fate and transport in agricultural settings. In order to assess these risks, and understanding of the factors that influence pathogen fate in agricultural settings is needed and is critical ...

  13. Pre-disinfection columns to improve the performance of the direct electro-disinfection of highly faecal-polluted surface water.

    PubMed

    Isidro, J; Llanos, J; Sáez, C; Lobato, J; Cañizares, P; Rodrigo, M A

    2018-09-15

    This work presents the design and evaluation of a new concept of pre-disinfection treatment that is especially suited for highly polluted surface water and is based on the combination of coagulation-flocculation, lamellar sedimentation and filtration into a single-column unit, in which the interconnection between treatments is an important part of the overall process. The new system, the so-called PREDICO (PRE-DIsinfection Column) system, was built with low-cost consumables from hardware stores (in order to promote in-house construction of the system in poor countries) and was tested with a mixture of 20% raw wastewater and 80% surface water (in order to simulate an extremely bad situation). The results confirmed that the PREDICO system helps to avoid fouling in later electro-disinfection processes and attains a remarkable degree of disinfection (3-4 log units), which supplements the removal of pathogens attained by the electrolytic cell (more than 4 log units). The most important sizing parameters for the PREDICO system are the surface loading rate (SLR) and the hydraulic residence time (HRT); SLR values under 20 cm min -1 and HRT values over 13.6 min in the PREDICO system are suitable to warrant efficient performance of the system. Copyright © 2018 Elsevier Ltd. All rights reserved.

  14. Removal of Cs+ from water and soil by ammonium-pillared montmorillonite/Fe3O4 composite.

    PubMed

    Zheng, Xianming; Dou, Junfeng; Yuan, Jing; Qin, Wei; Hong, Xiaoxi; Ding, Aizhong

    2017-06-01

    To remove cesium ions from water and soil, a novel adsorbent was synthesized by following a one-step co-precipitation method and using non-toxic raw materials. By combining ammonium-pillared montmorillonite (MMT) and magnetic nanoparticles (Fe 3 O 4 ), an MMT/Fe 3 O 4 composite was prepared and characterized. The adsorbent exhibited high selectivity of Cs + and could be rapidly separated from the mixed solution under an external magnetic field. Above all, the adsorbent had high removal efficiency in cesium-contaminated samples (water and soil) and also showed good recycling performance, indicating that the MMT/Fe 3 O 4 composite could be widely applied to the remediation of cesium-contaminated environments. It was observed that the pH, solid/liquid ratio and initial concentration affected adsorption capacity. In the presence of coexisting ions, the adsorption capacity decreased in the order of Ca 2+ >Mg 2+ >K + >Na + , which is consistent with our theoretical prediction. The adsorption behavior of this new adsorbent could be expressed by the pseudo-second-order model and Freundlich isotherm. In addition, the adsorption mechanism of Cs + was NH 4 + ion exchange and surface hydroxyl group coordination, with the former being more predominant. Copyright © 2016. Published by Elsevier B.V.

  15. In Pursuit of Nearshore Wave Characteristics- Implementation and Validation of a Shallow Water Correction for High Frequency Radars along the New Jersey Coast

    NASA Astrophysics Data System (ADS)

    Livermont, E. A.

    2014-12-01

    Within the U.S., coastal ocean current mapping with HF radar has matured to the point where it is now considered an essential component of regional ocean observing systems. A Mid-Atlantic HF radar network now provides high-resolution coverage within five localized networks, which are linked together to cover the full range of the Mid-Atlantic coast. While the primary focus of these networks has been on offshore current mapping observations, a long-term objective has been to develop and evaluate nearshore waves and currents. Of particular interest is the height of ocean waves that play a crucial role in engineering projects, ship navigation and design, vessel traffic control as well as shoreline protection, beach erosion, and mitigation of oil spills and ocean pollution. The radars owned by Rutgers University cover the coastline of New Jersey at multiple frequencies from 4.5 to 25 MHz. Their echoes contain information on both currents and waves from deep water up into the shallow coastal zone, providing an excellent archive for this study. Radar sea-echo spectra consist of dominant first-order peaks surrounded with lower-energy second-order structures. Present analysis methods assume that the waves do not interact with the ocean floor. The assumption of deep water is often invalid close to the coast and for broad continental shelves, and is particularly inadequate to describe the second-order sea-echo used to give information on ocean waves. Additionally, second-order echo is often only visible above the noise floor at close ranges. In this paper, a shallow water spectral theory is implemented at four locations on the New Jersey coast- Strathmere, Wildwood, Brant Beach, and Sea Bright. The corrected wave characteristics extracted from the HF radars were then compared to several in situ wave measurements. The first three sites—Strathmere, Wildwood and Brant Beach—were validated against two long-term (1999-2007) wave gauges deployed by Stevens Institute of Technology in 5 meters of water. Based on this initial comparison, several additional corrections to the radar processing were implemented. The site at Sea Bright was used for independent verification and validated against an ADCP deployed for three weeks in March 2012.

  16. Patchiness of phytoplankton and primary production in Liaodong Bay, China.

    PubMed

    Pei, Shaofeng; Laws, Edward A; Zhang, Haibo; Ye, Siyuan; Yuan, Hongming; Liu, Haiyue

    2017-01-01

    A comprehensive study of water quality, phytoplankton biomass, and photosynthetic rates in Liaodong Bay, China, during June and July of 2013 revealed two large patches of high biomass and production with dimensions on the order of 10 km. Nutrient concentrations were above growth-rate-saturating concentrations throughout the bay, with the possible exception of phosphate at some stations. The presence of the patches therefore appeared to reflect the distribution of water temperature and variation of light penetration restricted by water turbidity. There was no patch of high phytoplankton biomass or production in a third, linear patch of water with characteristics suitable for rapid phytoplankton growth; the absence of a bloom in that patch likely reflected the fact that the width of the patch was less than the critical size required to overcome losses of phytoplankton to turbulent diffusion. The bottom waters of virtually all of the eastern half of the bay were below the depth of the mixed layer, and the lowest bottom water oxygen concentrations, 3-5 mg L-1, were found in that part of the bay. The water column in much of the remainder of the bay was within the mixed layer, and oxygen concentrations in both surface and bottom waters exceeded 5 mg L-1.

  17. Patchiness of phytoplankton and primary production in Liaodong Bay, China

    PubMed Central

    Laws, Edward A.; Zhang, Haibo; Ye, Siyuan; Yuan, Hongming; Liu, Haiyue

    2017-01-01

    A comprehensive study of water quality, phytoplankton biomass, and photosynthetic rates in Liaodong Bay, China, during June and July of 2013 revealed two large patches of high biomass and production with dimensions on the order of 10 km. Nutrient concentrations were above growth-rate-saturating concentrations throughout the bay, with the possible exception of phosphate at some stations. The presence of the patches therefore appeared to reflect the distribution of water temperature and variation of light penetration restricted by water turbidity. There was no patch of high phytoplankton biomass or production in a third, linear patch of water with characteristics suitable for rapid phytoplankton growth; the absence of a bloom in that patch likely reflected the fact that the width of the patch was less than the critical size required to overcome losses of phytoplankton to turbulent diffusion. The bottom waters of virtually all of the eastern half of the bay were below the depth of the mixed layer, and the lowest bottom water oxygen concentrations, 3–5 mg L–1, were found in that part of the bay. The water column in much of the remainder of the bay was within the mixed layer, and oxygen concentrations in both surface and bottom waters exceeded 5 mg L–1. PMID:28235070

  18. A real-time control strategy for separation of highly polluted storm water based on UV-Vis online measurements--from theory to operation.

    PubMed

    Hoppe, H; Messmann, S; Giga, A; Gruening, H

    2011-01-01

    'Classical' real-time control (RTC) strategies in sewer systems are based on water level and flow measurements with the goal of activation of retention volume. The control system rule of 'clean (storm water) runoff into the receiving water - polluted runoff into the treatment plant' has been thwarted by rough operating conditions and lack of measurements. Due to the specific boundary conditions in the city of Wuppertal's separate sewer system (clean stream water is mixed with polluted storm water runoff) a more sophisticated--pollution-based--approach was needed. In addition the requirements to be met by the treatment of storm water runoff have become more stringent in recent years. To separate the highly-polluted storm water runoff during rain events from the cleaner stream flow a pollution-based real-time control (P-RTC) system was developed and installed. This paper describes the measurement and P-RTC equipment, the definition of total suspended solids as the pollution-indicating parameter, the serviceability of the system, and also gives a cost assessment. A sensitivity analysis and pollution load calculations have been carried out in order to improve the P-RTC algorithm. An examination of actual measurements clearly shows the ecological and economic advantages of the P-RTC strategy.

  19. A High Order Element Based Method for the Simulation of Velocity Damping in the Hyporheic Zone of a High Mountain River

    NASA Astrophysics Data System (ADS)

    Preziosi-Ribero, Antonio; Peñaloza-Giraldo, Jorge; Escobar-Vargas, Jorge; Donado-Garzón, Leonardo

    2016-04-01

    Groundwater - Surface water interaction is a topic that has gained relevance among the scientific community over the past decades. However, several questions remain unsolved inside this topic, and almost all the research that has been done in the past regards the transport phenomena and has little to do with understanding the dynamics of the flow patterns of the above mentioned interactions. The aim of this research is to verify the attenuation of the water velocity that comes from the free surface and enters the porous media under the bed of a high mountain river. The understanding of this process is a key feature in order to characterize and quantify the interactions between groundwater and surface water. However, the lack of information and the difficulties that arise when measuring groundwater flows under streams make the physical quantification non reliable for scientific purposes. These issues suggest that numerical simulations and in-stream velocity measurements can be used in order to characterize these flows. Previous studies have simulated the attenuation of a sinusoidal pulse of vertical velocity that comes from a stream and goes into a porous medium. These studies used the Burgers equation and the 1-D Navier-Stokes equations as governing equations. However, the boundary conditions of the problem, and the results when varying the different parameters of the equations show that the understanding of the process is not complete yet. To begin with, a Spectral Multi Domain Penalty Method (SMPM) was proposed for quantifying the velocity damping solving the Navier - Stokes equations in 1D. The main assumptions are incompressibility and a hydrostatic approximation for the pressure distributions. This method was tested with theoretical signals that are mainly trigonometric pulses or functions. Afterwards, in order to test the results with real signals, velocity profiles were captured near the Gualí River bed (Honda, Colombia), with an Acoustic Doppler Velocimeter (ADV). These profiles were filtered, treated and set up to feed the SMPM that solves the Navier - Stokes equations for the theoretical case. Besides, the velocity fluctuations along the river bed were calculated according to the mesh that was proposed to solve the numerical problem. This mesh required more refinement near the boundary conditions in order to calculate all the turbulent flow scales near the boundary. As a result, the velocity damping inside the porous media with real velocity pulses behaves similarly to the damping of the theoretical signals. However, there is still doubt about the use of the Navier - Stokes equations with the assumptions of incompressibility and hydrostatic approximation for the pressure distributions. Furthermore, the boundary conditions of the model suggest a great theme of discussion because of their nature. To sum up, the quantification of the interactions of groundwater and surface water have to be studied using numerical models in order to observe the behavior of the flow. Our research suggests that the velocity damping of water when entering the porous media goes beyond the approximations used for the Navier-Stokes equations and that this is a pressure driven flow that does not hold the hydrostatic simplification.

  20. International Comparison of Water Resources Utilization Efficiency in the Silk Road Economic Belt

    NASA Astrophysics Data System (ADS)

    Yan, Long; Ma, Jing; Deng, Wei; Wang, Yong

    2018-03-01

    In order to get knowledge of the standard of water utilization of the Silk Road Economic Belt from international point of view, the paper analyzes the annual variation of water resources utilization in the Silk Road Economic Belt, and compares with other typical countries. The study shows that Water resources utilization efficiency has been greatly improved in recent 20 years and the water consumption per USD 10000 of GDP has been declined 87.97%. the improvement of industrial water consumption efficiency is the key driving factors for substantial decrease in water consumption.The comparison of water utilization and human development shows that the higher HDI the country is, the more efficient water utilization the country has. water consumption per USD 10000 of GDP in country with HDI>0.9 is 194m³, being 8.5% of that in country with HDI from 0.5 to 0.6. On the premise of maintaining the stable economic and social development of the Silk Road Economic Belt, the realization of the control target of total water consumption must depend on the strict control over the disorderly expansion of irrigated area, the change in the mode of economic growth, the implementation of the development strategy for new industrialization and urbanization, vigorous development of the processing industry with low water consumption as well as the high-tech and high value-added industry. Only in this way, the control target of total water consumption can be realized in the process of completing the industrialization task.

  1. Effect of water on mechanical properties and stress corrosion behavior of alloy 600, alloy 690, EN82H welds, and EN52 welds

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

    Brown, C.M.; Mills, W.J.

    1999-02-01

    The fracture toughness and tensile properties of alloy 600 (UNS N06600), alloy 690 (UNS N06690), and their welds (EN82H [UNS N06082] and EN52 [UNS N06052]) were characterized in 54 C and 338 C water with an elevated hydrogen content. Results were compared with air data to evaluate the effect of low- and high-temperature water on the mechanical properties. In addition, the stress corrosion cracking (SCC) behavior of EN82H and EN52 welds was evaluated in 360 C water. Elastic-plastic (J{sub IC}) fracture toughness testing revealed that the fracture resistance of all test materials was exceptionally high in 54 C and 338more » C air and 338 C water, demonstrating that fracture properties essentially were unaffected by the high-temperature water environment. In 54 C water, however, J{sub IC} values for EN82H and EN52 welds were reduced by an order of magnitude, and alloy 690 showed a fivefold decrease in J{sub IC}. Scanning electron fractography revealed that the degraded fracture properties were associated with a fracture mechanism transition from ductile dimple rupture to intergranular cracking. The latter was associated with hydrogen-induced cracking mechanism. The fracture toughness for alloy 600 remained high in 54 C water, and microvoid coalescence was the operative mechanism in low-temperature air and water. Tensile properties for all test materials essentially were unaffected by the water environment, except for the total elongation for EN82H welds, which was reduced significantly in 54 C water. Constant-load testing of precracked weld specimens in 360 C water resulted in extensive intergranular SCC in EN82H welds, whereas no SCC occurred in EN52 welds under comparable test conditions.« less

  2. The role of dynamic surface water-groundwater exchange on streambed denitrification in a first-order, low-relief agricultural watershed

    NASA Astrophysics Data System (ADS)

    Rahimi, Mina; Essaid, Hedeff I.; Wilson, John T.

    2015-12-01

    The role of temporally varying surface water-groundwater (SW-GW) exchange on nitrate removal by streambed denitrification was examined along a reach of Leary Weber Ditch (LWD), Indiana, a small, first-order, low-relief agricultural watershed within the Upper Mississippi River basin, using data collected in 2004 and 2005. Stream stage, GW heads (H), and temperatures (T) were continuously monitored in streambed piezometers and stream bank wells for two transects across LWD accompanied by synoptic measurements of stream stage, H, T, and nitrate (NO3) concentrations along the reach. The H and T data were used to develop and calibrate vertical two-dimensional, models of streambed water flow and heat transport across and along the axis of the stream. Model-estimated SW-GW exchange varied seasonally and in response to high-streamflow events due to dynamic interactions between SW stage and GW H. Comparison of 2004 and 2005 conditions showed that small changes in precipitation amount and intensity, evapotranspiration, and/or nearby GW levels within a low-relief watershed can readily impact SW-GW interactions. The calibrated LWD flow models and observed stream and streambed NO3 concentrations were used to predict temporal variations in streambed NO3 removal in response to dynamic SW-GW exchange. NO3 removal rates underwent slow seasonal changes, but also underwent rapid changes in response to high-flow events. These findings suggest that increased temporal variability of SW-GW exchange in low-order, low-relief watersheds may be a factor contributing their more efficient removal of NO3.

  3. Presence and persistence of a highly ordered lipid phase state in the avian stratum corneum.

    PubMed

    Champagne, Alex M; Pigg, Victoria A; Allen, Heather C; Williams, Joseph B

    2018-06-07

    To survive high temperatures in a terrestrial environment, animals must effectively balance evaporative heat loss and water conservation. In passerine birds, cutaneous water loss (CWL) is the primary avenue of water loss at thermoneutral temperatures and increases slightly as ambient temperature increases, indicating a change in the permeability of the skin. In the stratum corneum (SC), the outermost layer of the skin, lipids arranged in layers called lamellae serve as the primary barrier to CWL in birds. The permeability of these lamellae depends in large part on the ability of lipid molecules to pack closely together in an ordered orthorhombic phase state. However, as temperature increases, lipids of the SC become more disordered, and may pack in more permeable hexagonal or liquid crystalline phase states. In this study, we used Fourier transform infrared spectroscopy to monitor the phase state of lipids in the SC of house sparrows ( Passer domesticus ) at skin temperatures ranging from 25 to 50°C. As temperature increased, lipids became slightly more disordered, but remained predominantly in the orthorhombic phase, consistent with the small increase in CWL observed in house sparrows as ambient temperature increases. These results differ considerably from studies on mammalian SC, which find a predominantly hexagonal arrangement of lipids at temperatures above 37°C, and the increased order in avian SC may be explained by longer lipid chain length, scarcity of cholesterol and the presence of cerebrosides. Our results lend further insight into the arrangement and packing of individual lipid molecules in avian SC. © 2018. Published by The Company of Biologists Ltd.

  4. The role of dynamic surface water-groundwater exchange on streambed denitrification in a first-order, low-relief agricultural watershed

    USGS Publications Warehouse

    Rahimi Kazerooni, Mina N.; Essaid, Hedeff I.; Wilson, John T.

    2015-01-01

    The role of temporally varying surface water-groundwater (SW-GW) exchange on nitrate removal by streambed denitrification was examined along a reach of Leary Weber Ditch (LWD), Indiana, a small, first-order, low-relief agricultural watershed within the Upper Mississippi River basin, using data collected in 2004 and 2005. Stream stage, GW heads (H), and temperatures (T) were continuously monitored in streambed piezometers and stream bank wells for two transects across LWD accompanied by synoptic measurements of stream stage, H, T, and nitrate (NO3) concentrations along the reach. The H and T data were used to develop and calibrate vertical two-dimensional, models of streambed water flow and heat transport across and along the axis of the stream. Model-estimated SW-GW exchange varied seasonally and in response to high-streamflow events due to dynamic interactions between SW stage and GW H. Comparison of 2004 and 2005 conditions showed that small changes in precipitation amount and intensity, evapotranspiration, and/or nearby GW levels within a low-relief watershed can readily impact SW-GW interactions. The calibrated LWD flow models and observed stream and streambed NO3 concentrations were used to predict temporal variations in streambed NO3 removal in response to dynamic SW-GW exchange. NO3 removal rates underwent slow seasonal changes, but also underwent rapid changes in response to high-flow events. These findings suggest that increased temporal variability of SW-GW exchange in low-order, low-relief watersheds may be a factor contributing their more efficient removal of NO3.

  5. Preparation of Hierarchical Highly Ordered Porous Films of Brominated Poly(phenylene oxide) and Hydrophilic SiO2/C Membrane via the Breath Figure Method

    PubMed Central

    Yuan, Hua; Yu, Bing; Chi, Ming; Cheng, Yuanzhe; Lv, Chunxin

    2018-01-01

    Porous permeable films materials have very broad prospects in the treatment of sludge-containing waste water due to their large surface area and good microfiltration. In this work, highly ordered porous membranes have been prepared successfully on ice substrates using a poly(phenylene oxide) (BPPO)-SiO2 nanoparticle (NP) mixture by the breath figure method. Based on the theory of Pickering emulsion system and capillary flow, particle assisted membrane formation was analyzed. Another two sorts of new membranes SiO2/C membrane and hierarchical porous polymer (HPP) membrane, which were obtained by modification of the BPPO-SiO2 membrane by calcination and etching, were set up in a further study. Their properties were investigated through the methods of scanning electron microscopy (SEM), fourier transform infrared spectrometry (FTIR), ultraviolet spectrum (UV), capillary electrophoresis (CE), contact angle, and water flux tests. All these results demonstrate that both surface hydrophilicity and fouling resistance of the membrane would be improved by using SiO2 as a filler. The membranes with high permeability and antifouling properties were used for microfiltration applications. PMID:29570622

  6. Proof of principle experiments for helicon discharges in hydrogen

    NASA Astrophysics Data System (ADS)

    Briefi, Stefan; Fantz, Ursel

    2013-09-01

    In order to reduce the amount of power required for generating CW hydrogen discharges with high electron densities and a high degree of dissociation via RF coupling, the helicon concept is investigated. For this purpose a small laboratory experiment (length of the discharge vessel 40 cm, diameter 10 cm) has been built up. The RF generator has a maximum power of 600 W (frequency 13.56 MHz) and a Nagoya type III antenna is applied. As water cooling was avoided in constructing the experiment for simplicity, the induction coils can only generate a rather low magnetic field up to 14 mT. The performed investigations cover a variation of the RF power and the magnetic field in a pressure range between 0.3 and 10 Pa. Around a magnetic field of 3 mT the low field peak which is typical for helicon discharges could be observed. As the high density mode of helicon discharges has not yet been reached, a different RF generator (2 MHz, 2 KW) and water cooled induction coils will be applied in a next step in order to increase the available power and the magnetic field.

  7. An Assessment of Research Gaps Related to Deep Water Wellbore Integrity

    NASA Astrophysics Data System (ADS)

    Tkach, M. K.; Radonjic, M.; Kutchko, B. G.

    2017-12-01

    In order for a deep-water wellbore to uphold its integrity under high pressure - high temperature conditions, the wellbore must possess complete zonal isolation while surrounded in an extreme environment. Highly variable temperature and pressure ranges, shallow flow zones, as well as potentially corrosive fluids and gasses all present unique challenges to the job of the cement which maintains that zonal isolation. As such, alternative options to mainstream choices often present themselves as attractive avenues of discovery. As it is of utmost importance to maintain structural integrity under HPHT conditions, cement slurries are pumped downhole to provide zonal isolation and structural support to offshore wells. The wellbore system potentially faces a variety of temperature and pressure fluctuations from the immediate onset. These fluctuations may affect the hydration properties of the cement. It is also important to consider the chemical interactions that the cement may have at the rock-cement interface where potential degradation or annulus gaps may occur further risking a decrease in zonal isolation. This presentation intends to review some of the important issues regarding zonal isolation in HPHT conditions and to highlight critical knowledge gaps in order to generate important research questions.

  8. Structure of the first- and second-neighbor shells of simulated water: Quantitative relation to translational and orientational order

    NASA Astrophysics Data System (ADS)

    Yan, Zhenyu; Buldyrev, Sergey V.; Kumar, Pradeep; Giovambattista, Nicolas; Debenedetti, Pablo G.; Stanley, H. Eugene

    2007-11-01

    We perform molecular dynamics simulations of water using the five-site transferable interaction potential (TIP5P) model to quantify structural order in both the first shell (defined by four nearest neighbors) and second shell (defined by twelve next-nearest neighbors) of a central water molecule. We find that the anomalous decrease of orientational order upon compression occurs in both shells, but the anomalous decrease of translational order upon compression occurs mainly in the second shell. The decreases of translational order and orientational order upon compression (called the “structural anomaly”) are thus correlated only in the second shell. Our findings quantitatively confirm the qualitative idea that the thermodynamic, structural, and hence dynamic anomalies of water are related to changes upon compression in the second shell.

  9. Re-evaluation and reconstruction of water purification system using soil. I. Assessment of soil as a sorbent of humic substances and phosphate ion.

    PubMed

    Fujikawa, Y; Hamasaki, T; Sugahara, M; Ozaki, H; Prasai, G; Yano, T; Imada, R; Tainaka, Y; Nakamura, W; Haruki, F

    2004-01-01

    The purpose of our study is to develop a treatment procedure for humic substances (HS hereafter) and phosphate ion in wastewater and environmental water by percolation of the water through a constructed soil layer at the hydraulic loading of a few metres per day. In the present work, batch sorption tests were conducted for more than 80 samples of soil, sludge, mineral and organic materials in order to find good sorbents for fulvic acid (FA hereafter) and phosphate ion. The results showed that the sorption of FA was high for some charcoal, and apatite and goethite minerals. Comparatively high sorption of FA was found for some Andosols and volcanic ash soil. Significant sorption of phosphate ion, on the other hand, was found for various types of soil, sludge from water treatment plants and some waste materials. The linear isotherm was obtained for the sorption of FA to a charcoal, apatite and goethite minerals, and Andosols.

  10. Modifying Surface Chemistry of Metal Oxides for Boosting Dissolution Kinetics in Water by Liquid Cell Electron Microscopy.

    PubMed

    Lu, Yue; Geng, Jiguo; Wang, Kuan; Zhang, Wei; Ding, Wenqiang; Zhang, Zhenhua; Xie, Shaohua; Dai, Hongxing; Chen, Fu-Rong; Sui, Manling

    2017-08-22

    Dissolution of metal oxides is fundamentally important for understanding mineral evolution and micromachining oxide functional materials. In general, dissolution of metal oxides is a slow and inefficient chemical reaction. Here, by introducing oxygen deficiencies to modify the surface chemistry of oxides, we can boost the dissolution kinetics of metal oxides in water, as in situ demonstrated in a liquid environmental transmission electron microscope (LETEM). The dissolution rate constant significantly increases by 16-19 orders of magnitude, equivalent to a reduction of 0.97-1.11 eV in activation energy, as compared with the normal dissolution in acid. It is evidenced from the high-resolution TEM imaging, electron energy loss spectra, and first-principle calculations where the dissolution route of metal oxides is dynamically changed by local interoperability between altered water chemistry and surface oxygen deficiencies via electron radiolysis. This discovery inspires the development of a highly efficient electron lithography method for metal oxide films in ecofriendly water, which offers an advanced technique for nanodevice fabrication.

  11. Possibility of wax control techniques in Indonesian oil fields

    NASA Astrophysics Data System (ADS)

    Abdurrahman, M.; Ferizal, F. H.; Husna, U. Z.; Pangaribuan, L.

    2018-03-01

    Wax is one of the common problem which can reduce the oil production, especially for the reservoir with high paraffin content case. When the temperature of crude oil is lower than pour point, wax molecules can begin rapidly precipitated. The impacts of this problem are the clogging of production equipment, sealing off the pores in the reservoir, and decreasing production flow rate. In order to solve the wax problem, several methods have been applied in some oil fields in the world. For example, chemical methods in Jiangsu field (China) and Mumbai High field (India), hot water in Mangala field (India), magnetic method in Daqing field (China), water-dispersible in Bakken basin (US), and microbial in Jidong field (China). In general, the various crude oils present in the Indonesia contain wax content between 10%-39% and pour point of 22°C-49°C. Hot water and chemical method are commonly used to solve wax problems in Indonesian oil fields. However, the primary solution is magnetic method, and the secondary solution is water dispersible.

  12. Cost Estimates Of Concentrated Photovoltaic Heat Sink Production

    DTIC Science & Technology

    2016-06-01

    steady year-round sunshine and in many cases high levels of direct normal irradiance (DNI). Beyond traditional PV , some climates favor rooftop solar ...water heating, but the majority of installed solar systems, are PV (EIA, 2015). Solar power generation has great benefits for the DON considering the...systems concentrate and focus sunlight onto a smaller focal point in order to take advantage of the highly efficient solar cells. Generally, PV

  13. A high-order time-parallel scheme for solving wave propagation problems via the direct construction of an approximate time-evolution operator

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

    Haut, T. S.; Babb, T.; Martinsson, P. G.

    2015-06-16

    Our manuscript demonstrates a technique for efficiently solving the classical wave equation, the shallow water equations, and, more generally, equations of the form ∂u/∂t=Lu∂u/∂t=Lu, where LL is a skew-Hermitian differential operator. The idea is to explicitly construct an approximation to the time-evolution operator exp(τL)exp(τL) for a relatively large time-step ττ. Recently developed techniques for approximating oscillatory scalar functions by rational functions, and accelerated algorithms for computing functions of discretized differential operators are exploited. Principal advantages of the proposed method include: stability even for large time-steps, the possibility to parallelize in time over many characteristic wavelengths and large speed-ups over existingmore » methods in situations where simulation over long times are required. Numerical examples involving the 2D rotating shallow water equations and the 2D wave equation in an inhomogenous medium are presented, and the method is compared to the 4th order Runge–Kutta (RK4) method and to the use of Chebyshev polynomials. The new method achieved high accuracy over long-time intervals, and with speeds that are orders of magnitude faster than both RK4 and the use of Chebyshev polynomials.« less

  14. Catchment-Scale Sampling Reveals the Consistent Function of the Sediment-Water Interface to Remove Landscape Scale Dissolved Organic Carbon Properties

    NASA Astrophysics Data System (ADS)

    Lee-Cullin, J. A.; Zarnetske, J. P.; Wiewiora, E.; Ruhala, S.; Hampton, T. B.

    2016-12-01

    Dissolved organic carbon (DOC) is a critical component to biogeochemical cycling and water quality in surface waters. As DOC moves through stream networks, from headwaters to higher order streams, the sediment-water interface (SWI), where streams and groundwater readily interact, exerts a strong influence on DOC concentrations and compositional characteristics (i.e., molecular properties). Few studies examine SWI patterns at larger spatial scales, instead focusing primarily on site-level studies because sampling in the SWI is methodologically time and labor intensive. It is presently unknown how land use and landcover influence the fate of DOC in the SWI and therefore the function of the SWI on catchment-scale DOC conditions. Here, we performed a catchment-scale, high spatial-resolution SWI sampling campaign to test how landscape pattern DOC signatures are propagated into the stream and groundwater, and to assess the fate of these signatures when DOC travels through the SWI. We sampled across 39 sites composed of first-, second-, and third-order locations in a lowland, third-order catchment composed of diverse landscape units and properties, including wetland, upland forest, and agriculture. At each of these locations, surface water, groundwater, and SWI water were collected, including six discrete depths across the SWI. The major land use and landcover properties were also determined for each of these locations. We developed two simple generalized linear models to identify the landscape properties with greatest explanatory power for DOC conditions - one for stream water and one for groundwater. The correlation between landscape properties and surface water DOC characteristics was stronger than between landscape properties and groundwater DOC characteristics. To test if the DOC properties from surface and groundwater were preserved or removed by the SWI, the resulting best-fit models for each water source were used to predict the DOC conditions across the SWI. The models were unable to predict SWI DOC conditions, indicating that the landscape signature present in both the surface water and groundwater is removed by processes occurring in the SWI. Overall, this suggests that the SWI functions as and effective zone for processing the landscape-derived DOC signatures.

  15. Catchment-Scale Sampling Reveals the Consistent Function of the Sediment-Water Interface to Remove Landscape Scale Dissolved Organic Carbon Properties

    NASA Astrophysics Data System (ADS)

    Lee-Cullin, J. A.; Zarnetske, J. P.; Wiewiora, E.; Ruhala, S.; Hampton, T. B.

    2017-12-01

    Dissolved organic carbon (DOC) is a critical component to biogeochemical cycling and water quality in surface waters. As DOC moves through stream networks, from headwaters to higher order streams, the sediment-water interface (SWI), where streams and groundwater readily interact, exerts a strong influence on DOC concentrations and compositional characteristics (i.e., molecular properties). Few studies examine SWI patterns at larger spatial scales, instead focusing primarily on site-level studies because sampling in the SWI is methodologically time and labor intensive. It is presently unknown how land use and landcover influence the fate of DOC in the SWI and therefore the function of the SWI on catchment-scale DOC conditions. Here, we performed a catchment-scale, high spatial-resolution SWI sampling campaign to test how landscape pattern DOC signatures are propagated into the stream and groundwater, and to assess the fate of these signatures when DOC travels through the SWI. We sampled across 39 sites composed of first-, second-, and third-order locations in a lowland, third-order catchment composed of diverse landscape units and properties, including wetland, upland forest, and agriculture. At each of these locations, surface water, groundwater, and SWI water were collected, including six discrete depths across the SWI. The major land use and landcover properties were also determined for each of these locations. We developed two simple generalized linear models to identify the landscape properties with greatest explanatory power for DOC conditions - one for stream water and one for groundwater. The correlation between landscape properties and surface water DOC characteristics was stronger than between landscape properties and groundwater DOC characteristics. To test if the DOC properties from surface and groundwater were preserved or removed by the SWI, the resulting best-fit models for each water source were used to predict the DOC conditions across the SWI. The models were unable to predict SWI DOC conditions, indicating that the landscape signature present in both the surface water and groundwater is removed by processes occurring in the SWI. Overall, this suggests that the SWI functions as and effective zone for processing the landscape-derived DOC signatures.

  16. Fluoride removal in water by a hybrid adsorbent lanthanum-carbon.

    PubMed

    Vences-Alvarez, Esmeralda; Velazquez-Jimenez, Litza Halla; Chazaro-Ruiz, Luis Felipe; Diaz-Flores, Paola E; Rangel-Mendez, Jose Rene

    2015-10-01

    Various health problems associated with drinking water containing high fluoride levels, have motivated researchers to develop more efficient adsorbents to remove fluoride from water for beneficial concentrations to human health. The objective of this research was to anchor lanthanum oxyhydroxides on a commercial granular activated carbon (GAC) to remove fluoride from water considering the effect of the solution pH, and the presence of co-existing anions and organic matter. The activated carbon was modified with lanthanum oxyhydroxides by impregnation. SEM and XRD were performed in order to determine the crystal structure and morphology of the La(III) particles anchored on the GAC surface. FT-IR and pK(a)'s distribution were determined in order to elucidate both the possible mechanism of the lanthanum anchorage on the activated carbon surface and the fluoride adsorption mechanism on the modified material. The results showed that lanthanum ions prefer binding to carboxyl and phenolic groups on the activated carbon surface. Potentiometric titrations revealed that the modified carbon (GAC-La) possesses positive charge at a pH lower than 9. The adsorption capacity of the modified GAC increased five times in contrast to an unmodified GAC adsorption capacity at an initial F(-) concentration of 20 mg L(-1). Moreover, the presence of co-existing anions had no effect on the fluoride adsorption capacity at concentrations below 30 mg L(-1), that indicated high F(-) affinity by the modified adsorbent material (GAG-La). Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Poly (vinyl alcohol)/gum karaya electrospun plasma treated membrane for the removal of nanoparticles (Au, Ag, Pt, CuO and Fe3O4) from aqueous solutions.

    PubMed

    Padil, Vinod Vellora Thekkae; Černík, Miroslav

    2015-04-28

    In the present work, nanofibre membranes composed of polyvinyl alcohol (PVA) and a natural gum karaya (GK) hydrocolloid were prepared using electrospinning. The electrospun membranes of PVA/GK were cross-linked with heat treatment and later methane plasma was used to obtain a hydrophobic membrane. The morphology, characterization and adsorption ability of P-NFM was assessed using scanning electron microscopy, UV-vis spectroscopy, ATR-FTIR techniques, water contact angle and ICP-MS analytical methods. The membrane was employed for the extraction of nanoparticles (Ag, Au, Pt, CuO and Fe3O4) from water. The nanoparticle extraction kinetic and adsorption isotherm perform the pseudo-second-order model and Langmuir isotherm model, respectively. The adsorption capacities of the membrane for the removal of NPs from water diverge in the order Pt>Au>Ag>CuO>Fe3O4. The high adsorption efficiency for the removal of NPs from water was compared with an untreated membrane. Physisorption, functional group interactions, complexation reactions between metal/metal oxide nanoparticles with various functional groups present in NFM and modified surface properties such as the balance of hydrophilicity/hydrophobicity, surface free energy, and the high surface area of the plasma treated membrane were possible mechanisms of NPs adsorption onto NFM. The regeneration and reusability were tested in five consecutive adsorption/desorption cycles. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Superheating of monolayer ice in graphene nanocapillaries

    NASA Astrophysics Data System (ADS)

    Zhu, YinBo; Wang, FengChao; Wu, HengAn

    2017-04-01

    The freezing and melting of low-dimensional materials, either via a first-order phase transition or without any discontinuity in thermodynamic, still remain a matter of debate. Melting (superheating) in two-dimensional (2D) ice is fundamentally different from that in bulk counterpart. Here, we perform comprehensive molecular dynamics simulations of the superheating of monolayer ice in graphene nanocapillaries to understand the nature of melting transition in 2D water/ice. We find four different superheating (melting) scenarios can happen in the superheating of monolayer square-like ice, which are closely related to the lateral pressure and the channel width. The anomalous two-stage melting transition with arisen coexistence phase is found, which reveals the unknown extraordinary characteristics of melting in 2D water/ice. Under ultrahigh lateral pressure, the intermediate monolayer triangular amorphous ice will be formed during the superheating of monolayer square-like ice with both continuous-like and first-order phase transitions. Whereas, under low lateral pressure, the melting in monolayer square-like ice manifests typical discontinuity with notable hysteresis-loop in potential energy during the heating/cooling process. Moreover, we also find that highly puckered monolayer square-like ice can transform into bilayer AB-stacked amorphous ice with square pattern in the superheating process. The superheating behavior under high lateral pressure can be partly regarded as the compression limit of superheated monolayer water. The intrinsic phenomena in our simulated superheating of monolayer ice may be significant for understanding the melting behavior in 2D water/ice.

  19. Superheating of monolayer ice in graphene nanocapillaries.

    PubMed

    Zhu, YinBo; Wang, FengChao; Wu, HengAn

    2017-04-07

    The freezing and melting of low-dimensional materials, either via a first-order phase transition or without any discontinuity in thermodynamic, still remain a matter of debate. Melting (superheating) in two-dimensional (2D) ice is fundamentally different from that in bulk counterpart. Here, we perform comprehensive molecular dynamics simulations of the superheating of monolayer ice in graphene nanocapillaries to understand the nature of melting transition in 2D water/ice. We find four different superheating (melting) scenarios can happen in the superheating of monolayer square-like ice, which are closely related to the lateral pressure and the channel width. The anomalous two-stage melting transition with arisen coexistence phase is found, which reveals the unknown extraordinary characteristics of melting in 2D water/ice. Under ultrahigh lateral pressure, the intermediate monolayer triangular amorphous ice will be formed during the superheating of monolayer square-like ice with both continuous-like and first-order phase transitions. Whereas, under low lateral pressure, the melting in monolayer square-like ice manifests typical discontinuity with notable hysteresis-loop in potential energy during the heating/cooling process. Moreover, we also find that highly puckered monolayer square-like ice can transform into bilayer AB-stacked amorphous ice with square pattern in the superheating process. The superheating behavior under high lateral pressure can be partly regarded as the compression limit of superheated monolayer water. The intrinsic phenomena in our simulated superheating of monolayer ice may be significant for understanding the melting behavior in 2D water/ice.

  20. Remote measurement of high preeruptive water vapor emissions at Sabancaya volcano by passive differential optical absorption spectroscopy

    USGS Publications Warehouse

    Kern, Christoph; Masias, Pablo; Apaza, Fredy; Reath, Kevin; Platt, Ulrich

    2017-01-01

    Water (H2O) is by far the most abundant volcanic volatile species and plays a predominant role in driving volcanic eruptions. However, numerous difficulties associated with making accurate measurements of water vapor in volcanic plumes have limited their use as a diagnostic tool. Here we present the first detection of water vapor in a volcanic plume using passive visible-light differential optical absorption spectroscopy (DOAS). Ultraviolet and visible-light DOAS measurements were made on 21 May 2016 at Sabancaya Volcano, Peru. We find that Sabancaya's plume contained an exceptionally high relative water vapor abundance 6 months prior to its November 2016 eruption. Our measurements yielded average sulfur dioxide (SO2) emission rates of 800–900 t/d, H2O emission rates of around 250,000 t/d, and an H2O/SO2 molecular ratio of 1000 which is about an order of magnitude larger than typically found in high-temperature volcanic gases. We attribute the high water vapor emissions to a boiling-off of Sabancaya's hydrothermal system caused by intrusion of magma to shallow depths. This hypothesis is supported by a significant increase in the thermal output of the volcanic edifice detected in infrared satellite imagery leading up to and after our measurements. Though the measurement conditions encountered at Sabancaya were very favorable for our experiment, we show that visible-light DOAS systems could be used to measure water vapor emissions at numerous other high-elevation volcanoes. Such measurements would provide observatories with additional information particularly useful for forecasting eruptions at volcanoes harboring significant hydrothermal systems.

  1. Fast arsenic speciation in water by on-site solid phase extraction and high-resolution continuum source graphite furnace atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Mihucz, Victor G.; Bencs, László; Koncz, Kornél; Tatár, Enikő; Weiszburg, Tamás; Záray, Gyula

    2017-02-01

    A method of high-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS-GFAAS), combined with on-site separation/solid phase extraction (SPE) has been developed for the speciation of inorganic As (iAs) in geothermal and drinking water samples. The HR-CS-GFAAS calibration curves were linear up to 200 μg/L As, but using second order polynomial fitting, accurate calibration could be performed up to 500 μg/L. It has been demonstrated that sample pH should not be higher than 8 for an accurate speciation of As(V) with a recovery of ≈ 95%. Geothermal water had fairly high salt content (≈ 2200 mg/L) due to the presence of chlorides and sulfates at mg/L levels. Therefore, a two-fold dilution of these types of samples before SPE is recommended, especially, for total As determinations, when the As concentration is as high as 400 μg/L. For drinking water, sampled from public wells with records of As concentrations higher than the 10 μg/L in the past, the reduction of As contamination below the WHO's health limit value could be observed. However, the electrical conductivity was close to 2500 μS/cm, i.e., the guideline limit for drinking water, which was due to their higher chloride content. The proposed fit-for-purpose SPE-HR-CS-GFAAS method could be a candidate for screening drinking water quality.

  2. Long-term variability of supratidal coastal boulder activation in Brittany (France)

    NASA Astrophysics Data System (ADS)

    Autret, Ronan; Dodet, Guillaume; Suanez, Serge; Roudaut, Gildas; Fichaut, Bernard

    2018-03-01

    High-energy supratidal coastal boulder deposit (SCBD) dynamics were investigated on Vierge Island and Pors Carn Point, north and south of western Brittany, France, respectively. Morphological changes induced by boulder transport and quarrying were quantified using high-resolution topographic survey data taken between 2012 and 2017. Additional in-situ wave parameters and water levels were also recorded over this period (2014-2017) in order to compute the maximum water levels and assess the relationship between SCBD morphological changes and specific hydrodynamic conditions. During extreme water levels (for maximum water levels exceeding a one in ten year event), SCBDs were broadly reworked (up to 40% of the total volume). During lower intensity events, for which maximum water levels were still very high, morphological changes represented 1% to 5% of the total volume. These morphological and hydrodynamic observations were then used to calibrate a chronology of SCBD activation events based on 70 years of hindcast winter maximum water levels. These long-term time-series showed great interannual variability in SCBD activation but no significant long-term trend. Winter-frequency SCBD activation was better correlated to the WEPA index (r = 0.46) than the NAO index (r = 0.1). Therefore, the WEPA index can be considered to be a more significant climate proxy for assessing storm-related geomorphic changes in the temperate latitudes of the N-E Atlantic basin (36°-52° N), including the Brittany coast. The potential of SCBDs as a morphological storm proxy for macrotidal high-energy rocky coasts is addressed.

  3. Advancement in Electrospun Nanofibrous Membranes Modification and Their Application in Water Treatment

    PubMed Central

    Nasreen, Shaik Anwar Ahamed Nabeela; Sundarrajan, Subramanian; Nizar, Syed Abdulrahim Syed; Balamurugan, Ramalingam; Ramakrishna, Seeram

    2013-01-01

    Water, among the most valuable natural resources available on earth, is under serious threat as a result of undesirable human activities: for example, marine dumping, atmospheric deposition, domestic, industrial and agricultural practices. Optimizing current methodologies and developing new and effective techniques to remove contaminants from water is the current focus of interest, in order to renew the available water resources. Materials like nanoparticles, polymers, and simple organic compounds, inorganic clay materials in the form of thin film, membrane or powder have been employed for water treatment. Among these materials, membrane technology plays a vital role in removal of contaminants due to its easy handling and high efficiency. Though many materials are under investigation, nanofibers driven membrane are more valuable and reliable. Synthetic methodologies applied over the modification of membrane and its applications in water treatment have been reviewed in this article. PMID:24957057

  4. Stability assessment of the chemical composition of the treated mining water used to replenish the cooling circuit in Jaworzno III Power Plant - Power Plant II

    NASA Astrophysics Data System (ADS)

    Karpiński, Marcin; Kmiecik, Ewa

    2017-11-01

    In Poland, electricity is still produced mainly in conventional power plants where fuel and water are materials necessary to generate the electricity. Even in modern power plants operating according to the principles of the sustainable development, this involves a high intake of water and considerable production of wastewater. This, in turn, necessi-tates the application of some technological solutions aimed at limiting the negative impact on the environment. The Jaworzno III Power Plant - Power Plant II is located in Jaworzno, Silesian Province, Poland. In order to minimise the negative impact on the surface water, the plant replenishes the cooling circuit with the mining water obtained from the closed-down Jan Kanty mine. The paper presents a stability assessment of the chemical composition of the treated mining water used to replenish the cooling circuit based on the data from 2007-2017.

  5. Fluoride concentration level in rural area in Poldasht city and daily fluoride intake based on drinking water consumption with temperature.

    PubMed

    Mohammadi, Ali Akbar; Yousefi, Mahmood; Mahvi, Amir Hossein

    2017-08-01

    Long-term exposure to high level of fluoride can caused several adverse effects on human health including dental and skeletal fluorosis. We investigated all the drinking water source located in rural areas of Poldasht city, west Azerbaijan Province, North West Iran between 2014 and 2015. Fluoride concentration of water samples was measured by SPADNS method. We found that in the villages of Poldasht the average of fluoride concentration in drinking water sources (well, and the river) was in the range mg/l 0.28-10.23. The average daily received per 2 l of drinking water is in the range mg/l 0.7-16.6 per day per person. Drinking water demands cause fluorosis in the villages around the area residents and based on the findings of this study writers are announced suggestions below in order to take care of the health of area residents.

  6. Chemical reaction between water vapor and stressed glass

    NASA Technical Reports Server (NTRS)

    Soga, N.; Okamoto, T.; Hanada, T.; Kunugi, M.

    1979-01-01

    The crack velocity in soda-lime silicate glass was determined at room temperature at water-vapor pressures of 10 to 0.04 torr using the double torsion technique. A precracked glass specimen (70 x 16 x 1.6 mm) was placed in a vacuum chamber containing a four-point bending test apparatus. The plotted experimental results show that the crack propagation curve in water agrees fairly well with that of Wiederhorn (1967). Attention is given to the effect of water vapor pressure on crack velocity at K(I) = 550,000 N/m to the 3/2 power, with (Wiederhorn's data) or without N2 present. The plotted results reveal that the present crack velocity is about two orders of magnitude higher than that of Wiederhorn at high water-vapor conditions, but the difference decreases as the water-vapor concentration diminishes or the crack velocity slows down.

  7. [Drinking water hardness and chronic degenerative diseases. II. Cardiovascular diseases].

    PubMed

    Monarca, S; Zerbini, I; Simonati, C; Gelatti, U

    2003-01-01

    Since the 1950s a causal relation between water hardness and cardiovascular diseases (CVD) in humans has been hypothesized. In order to evaluate the influence of calcium and magnesium, the minerals responsible for the hardness of drinking water, on human health, a review of all the articles published on the subject from 1980 up to today has been carried out. Many but not all geographic correlation studies showed an inverse association between water hardness and mortality for CVD. Most case-control and one cohort studies showed an inverse relation, statistically significant, between mortality from CVD and water levels of magnesium, but not calcium. Consumption of water containing high concentrations of magnesium seems to reduce of about 30-35% the mortality for CVD, but not the incidence. This inverse association is supported by clinical and experimental findings and is biologically plausible and in line with Hill's criteria for a cause-effect relationship.

  8. Efficient photochemistry of coronene:water complexes

    NASA Astrophysics Data System (ADS)

    Noble, J. A.; Jouvet, C.; Aupetit, C.; Moudens, A.; Mascetti, J.

    2017-03-01

    The photochemistry of ices with polycyclic aromatic hydrocarbons (PAHs) has been extensively studied, but to date no investigation has been made of PAHs in interaction with low numbers (n< 4) of molecules of water. We performed photochemical matrix isolation studies of coronene:water complexes, probing the argon matrix with FTIR spectroscopy. We find that coronene readily reacts with water upon irradiation with a mercury vapour lamp to produce oxygenated PAH photoproducts, and we postulate a reaction mechanism via a charge transfer Rydberg state. This result suggests that oxygenated PAHs should be widely observed in regions of the ISM with sufficiently high water abundances, for example near the edges of molecular clouds where water molecules begin to form, but before icy layers are observed, that is at AV< 3. In order to explain the low derived observational abundances of oxygenated PAHs, additional destruction routes must be invoked.

  9. Water-quality trends in New England rivers during the 20th century

    USGS Publications Warehouse

    Robinson, Keith W.; Campbell, Jean P.; Jaworski, Norbert A.

    2003-01-01

    Water-quality data from the Merrimack, Blackstone, and Connecticut Rivers in New England during parts of the 20th century were examined for trends in concentrations of sulfate, chloride, residue upon evaporation, nitrate, and total phosphorus. The concentrations of all five of these constituents show statistically significant trends during the century. Annual concentrations of sulfate and total phosphorus decreased during the second half of the century, whereas annual concentrations of nitrate, chloride, and residues increased throughout the century. In the Merrimack River, annual chloride concentrations increased by an order of magnitude. Annual nitrate concentrations also increased by an order of magnitude in the Merrimack and Connecticut Rivers. These changes in the water quality probably are related to changing human activities. Most notable is the relation between increasing use of road de-icing salts and chloride concentrations in rivers. In addition, changes in concentrations of nitrate and phosphorus probably are related to agricultural use of nitrogen and phosphorus fertilizers. For all the water-quality constituents assessed, concentrations were greatest in the Blackstone River. The Blackstone River Basin is smaller and more highly urbanized than the other basins studied. Data-collection programs that span multiple decades can provide valuable insight on the effects of changing human population and societal activities on the water quality of rivers. This study was done as part of the U.S. Geological Survey's National Water-Quality Assessment Program.

  10. Development of an integrated water resources management plan for the Lake Manyara sub-basin, Northern Tanzania

    NASA Astrophysics Data System (ADS)

    Ngana, J. O.; Mwalyosi, R. B. B.; Madulu, N. F.; Yanda, P. Z.

    Water resources management in Lake Manyara sub-basin is an issue of very high significance as the sub-basin hosts a number of national and global assets of great socio-cultural, ecological and economic values. The sub-basin comprise of a Biosphere Reserve with boosting tourism from Lake Manyara National Park with a variety of wildlife population, large livestock population and highly fertile land for agricultural production. The prevailing system of uncoordinated water resources management in the sub-basin cannot sustain the ever increasing water needs of the various expanding sectors, therefore a strategy must be sought to integrate the various sectoral needs against the available water resources in order to attain both economic and ecological sustainability. Through participatory approach with the stakeholders, the study has established key issues, demonstrated considerable experience in water resources management in the sub-basin including existence of water boards, water committees in some districts as well as land resources management practices However, a number of constraints were noted which inhibit sustainable water resources management including ignorance of water policies, conflicting sectoral policies, lack of coordination between sectors, high in migration rates into the basin, heavy in migration of livestock, conflicts between sectors, poor land use resulting in soil erosion and sedimentation, lack of comprehensive data base on water resources and water needs for : domestic, tourism, livestock, irrigation, wild life and environmental flows. As a way forward it was recommended that a basin wide legally mandated body (involving all levels) be established to oversee water use in the sub-basin. Other strategies include capacity building of stakeholders on water natural resources management policies, water rights and enforcement of laws. This progress report paper highlights the wealth of knowledge that stakeholders possess on water resources management and using that platform develop a participatory Integrated water resources management where roles and responsibilities are ironed out.

  11. 78 FR 52561 - Public Land Order No. 7820; Partial Modification, Public Water Reserve No. 107; Utah

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-23

    ...-52455] Public Land Order No. 7820; Partial Modification, Public Water Reserve No. 107; Utah AGENCY: Bureau of Land Management, Interior. ACTION: Public Land Order. SUMMARY: This order partially modifies a withdrawal created by an Executive Order insofar as it affects 264.21 acres of public lands withdrawn from...

  12. On the possible origin of bulk third harmonic generation in skin cells

    NASA Astrophysics Data System (ADS)

    Su, Tung-Yu; Liao, Chien-Sheng; Yang, Chih-Yuan; Zhuo, Guan-Yu; Chen, Szu-Yu; Chu, Shi-Wei

    2011-09-01

    We studied third harmonic generation (THG) of melanin solution with concentrations similar to melanocytes in human skin. In contrast to conventional observation of THG at interface, bulk THG was detected inside the solution due to the formation of melanin hydrocolloids. A linear relationship between melanin concentration and THG intensity was found, suggesting THG originated from high-order hyper-Rayleigh scattering. By fitting this linear relationship, third-order hyperpolarizability of melanin hydrocolloids was determined to be three orders larger than that of water. Our result will be useful for interpretation of THG signals in skin and other tissues containing colloidal particles.

  13. [Comparative studies on the action of chlorine and ozone on polioviruses in the reprocessing of drinking water in Essen (author's transl)].

    PubMed

    Thraenhart, O; Kuwert, E

    1975-07-01

    The present study was performed in order to evaluate comparatively the inactivation of polio virus type I strains (wild type and attenuated) by means of chlorine and ozone. Polio virus type I was chosen with regard to its epidemiological behaviour and high stability in drinking-water and sewage lines. In view of the lack of propagation techniques, hepatitis viruses A and B, unfortunately, could not be used for these experiments. The experiments were done under laboratory conditions only, and not in the water recovery plant because of hygienic reasons. Defined quantities of disinfectants were examined for their virus-inactivating effect in water without redox-potential (double-distilled water), water with low defined redox-potential (double-distilled water + KOH), previously chlorinated water with a residual chlorine content of 0.03 mg chlorine per liter (tap water) and water with a high redox-potential (well water from the drinking-water plant). Time-course studies were performed, both with chlorine and ozone, in order to evaluate the characteristics of the inactivation procedure. The experimental conditions chosen varied from experiment to experiment to obtain relevant conclusions for the practice. On the basis of our results, and taking into account the quantitative differences in effect, chlorine and ozone principially can be considered equivalent in their action of virus-disinfection. Both, the initial rate and the kinetics of virus disinfection are really identical. Both disinfectants are dependant on the condition of the water (redox-potential, pH etc.) to a great extent in their efficacy. Therefore, a decision of whether or not ozone should substitute for chlorine for the drinking-water supply in Essen cannot be drawn on the basis of virological experiments. This decision, then, depends more or less on other questions - such as relative costs and practicability of the ozonization on a large technical scale. The safety risk and technical reliability of the ozonization process is of particular significance. In the present condition of the Essen reservoir water, a good virus disinfection can be expected already with 1.0 to 1.5 mg ozone/liter (dissolved!); such a concentration guarantees very little residual ozone and, thus, makes then this procedure technically feasible. Continuous checking of the redox-potential and the amount of the ozone added is necessary. With regard to a continuous supply of ozone, the dependence on current supply must be guaranteed. Ozonization of water, probably by the cleavage of humic acid, promotes bacterial recontamination of the drinking-water in the city taps(Stalder und Klosterkötter, 45). Therefore only a combined pre-ozonization with subsequent chlorination would guarantee, both, safety and improvement of the cosmetical conditions of the drinking-water. Such a combination would be feasible with highly reduced amounts of ozone and chlorine.

  14. 76 FR 38144 - Energy Conservation Program for Consumer Products; Decision and Order Granting a Waiver to BSH...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-29

    ... measuring energy and water consumption. DATES: This Decision and Order is effective June 29, 2011. FOR... and water based on an estimate that at least 50% of homes already have a water softening system. BSH... Conservation Program for Consumer Products; Decision and Order Granting a Waiver to BSH Corporation From the...

  15. Experimental validation of a 2D overland flow model using high resolution water depth and velocity data

    NASA Astrophysics Data System (ADS)

    Cea, L.; Legout, C.; Darboux, F.; Esteves, M.; Nord, G.

    2014-05-01

    This paper presents a validation of a two-dimensional overland flow model using empirical laboratory data. Unlike previous publications in which model performance is evaluated as the ability to predict an outlet hydrograph, we use high resolution 2D water depth and velocity data to analyze to what degree the model is able to reproduce the spatial distribution of these variables. Several overland flow conditions over two impervious surfaces of the order of one square meter with different micro and macro-roughness characteristics are studied. The first surface is a simplified representation of a sinusoidal terrain with three crests and furrows, while the second one is a mould of a real agricultural seedbed terrain. We analyze four different bed friction parameterizations and we show that the performance of formulations which consider the transition between laminar, smooth turbulent and rough turbulent flow do not improve the results obtained with Manning or Keulegan formulas for rough turbulent flow. The simulations performed show that using Keulegan formula with a physically-based definition of the bed roughness coefficient, a two-dimensional shallow water model is able to reproduce satisfactorily the flow hydrodynamics. It is shown that, even if the resolution of the topography data and numerical mesh are high enough to include all the small scale features of the bed surface, the roughness coefficient must account for the macro-roughness characteristics of the terrain in order to correctly reproduce the flow hydrodynamics.

  16. Titanium based flat heat pipes for computer chip cooling

    NASA Astrophysics Data System (ADS)

    Soni, Gaurav; Ding, Changsong; Sigurdson, Marin; Bozorgi, Payam; Piorek, Brian; MacDonald, Noel; Meinhart, Carl

    2008-11-01

    We are developing a highly conductive flat heat pipe (called Thermal Ground Plane or TGP) for cooling computer chips. Conventional heat pipes have circular cross sections and thus can't make good contact with chip surface. The flatness of our TGP will enable conformal contact with the chip surface and thus enhance cooling efficiency. Another limiting factor in conventional heat pipes is the capillary flow of the working fluid through a wick structure. In order to overcome this limitation we have created a highly porous wick structure on a flat titanium substrate by using micro fabrication technology. We first etch titanium to create very tall micro pillars with a diameter of 5 μm, a height of 40 μm and a pitch of 10 μm. We then grow a very fine nano structured titania (NST) hairs on all surfaces of the pillars by oxidation in H202. In this way we achieve a wick structure which utilizes multiple length scales to yield high performance wicking of water. It's capable of wicking water at an average velocity of 1 cm/s over a distance of several cm. A titanium cavity is laser-welded onto the wicking substrate and a small quantity of water is hermetically sealed inside the cavity to achieve a TGP. The thermal conductivity of our preliminary TGP was measured to be 350 W/m-K, but has the potential to be several orders of magnitude higher.

  17. Mountains of the world: vulnerable water towers for the 21st century.

    PubMed

    Messerli, Bruno; Viviroli, Daniel; Weingartner, Rolf

    2004-11-01

    Mountains as "Water Towers" play an important role for the surrounding lowlands. This is particularly true of the world's semiarid and arid zones, where the contributions of mountains to total discharge are 50-90%. Taking into account the increasing water scarcity in these regions, especially for irrigation and food production, then today's state of knowledge in mountain hydrology makes sustainable water management and an assessment of vulnerability quite difficult. Following the IPCC report, the zone of maximum temperature increase in a 2 x CO2 state extends from low elevation in the arctic and sub-arctic to high elevation in the tropics and subtropics. The planned GCOS climate stations do not reach this elevation of high temperature change, although there are many high mountain peaks with the necessary sensitive and vulnerable ecosystems. Worldwide, more than 700 million people live in mountain areas, of these, 625 million are in developing countries. Probably more than half of these 625 million people are vulnerable to food insecurity. Consequences of this insecurity can be emigration or overuse of mountain ecosystems. Overuse of the ecosystems will, ultimately, have negative effects on the environment and especially on water resources. New research initiatives and new high mountain observatories are needed in order to understand the ongoing natural and human processes and their impacts on the adjacent lowlands.

  18. Use of surface water in drinking water production associated with municipal Legionnaires' disease incidence.

    PubMed

    Den Boer, J W; Coutinho, R A; Yzerman, E P F; van der Sande, M A B

    2008-04-01

    Given an observed geographical variation in Legionnaires' disease incidence in The Netherlands, the aim of the study was to test the hypothesis that the type of drinking water production was an independent determinant of the incidence of Legionnaires' disease. For the 1987-2005 period, the incidence of Legionnaires' disease in The Netherlands and the price of water as a proxy for production type was studied at the municipal level. The data on the price of water were available at the municipal level. For each of the 466 municipalities in The Netherlands a mean standardised incidence rate per 100,000 inhabitants over the 1987-2005 period was calculated, excluding patients with the most probable source of infection abroad or in hospital. Logistic regression was used to assess the relation of the price of water to the incidence rates. In order to control for diagnostic and inclusion bias, they were estimated using questionnaire data collected from all 62 medical microbiology laboratories in the country. The incidence of Legionnaires' disease varied between municipalities from 0.0 to 5.6 per 100,000 person-years. In univariate analysis high versus low water price was positively associated with a high municipal incidence rate (odds ratio (OR) 1.9; 95% CI 1.5-2.6). The association persisted (OR 5.1; 95% CI 3.2-8.0) after correction for diagnostic and inclusion bias. The price of water as a proxy for the type of water production was an independent risk factor for high municipal Legionnaires' disease incidence in The Netherlands. This can guide future prevention policies.

  19. Rocky-shore communities as indicators of water quality: a case study in the Northwestern Mediterranean.

    PubMed

    Pinedo, Susana; García, María; Satta, Maria Paola; de Torres, Mariona; Ballesteros, Enric

    2007-01-01

    The collection of 152 samples from the upper sublittoral zone along the rocky coasts of Catalonia (Northwestern Mediterranean) was carried out in 1999 in order to test the suitability of littoral communities to be used as indicators of water quality in the frame of the European Water Framework Directive. Detrended correspondence analysis were performed to distinguish between different communities and to relate communities composition to water quality. Samples collected in reference sites were included in the analysis. Mediterranean rocky shore communities situated in the upper sublittoral zone can be used as indicators of the water quality: there is a gradient from high to bad status that comprises from dense Cystoseira mediterranea forests to green algae dominated communities. The geographical patterns in the distribution of these communities show that the best areas are situated in the Northern coast, where tourism is the main economic resource of the area, and the worst area is situated close to the metropolitan zone of Barcelona with high population and industrial development. Thus, Mediterranean sublittoral rocky shore communities are useful indicators of water quality and multivariate analysis are a suitable statistical tool for the assessment of the ecological status.

  20. Water produced with coal-bed methane

    USGS Publications Warehouse

    ,

    2000-01-01

    Natural gas produced from coal beds (coal-bed methane, CBM) accounts for about 7.5 percent of the total natural gas production in the United States. Along with this gas, water is also brought to the surface. The amount of water produced from most CBM wells is relatively high compared to conventional natural gas wells because coal beds contain many fractures and pores that can contain and transmit large volumes of water. In some areas, coal beds may function as regional or local aquifers and important sources for ground water. The water in coal beds contributes to pressure in the reservoir that keeps methane gas adsorbed to the surface of the coal. This water must be removed by pumping in order to lower the pressure in the reservoir and stimulate desorption of methane from the coal (fi g. 1). Over time, volumes of pumped water typically decrease and the production of gas increases as coal beds near the well bore are dewatered.

  1. 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.

  2. Hydration energies and structures of alkaline earth metal ions, M2+(H2O)n, n = 5-7, M = Mg, Ca, Sr, and Ba.

    PubMed

    Rodriguez-Cruz, S E; Jockusch, R A; Williams, E R

    1999-09-29

    The evaporation of water from hydrated alkaline earth metal ions, produced by electrospray ionization, was studied in a Fourier transform mass spectrometer. Zero-pressure-limit dissociation rate constants for loss of a single water molecule from the hydrated divalent metal ions, M(2+)(H(2)O)(n) (M = Mg, Ca, and Sr for n = 5-7, and M = Ba for n = 4-7), are measured as a function of temperature using blackbody infrared radiative dissociation. From these values, zero-pressure-limit Arrhenius parameters are obtained. By modeling the dissociation kinetics using a master equation formalism, threshold dissociation energies (E(o)) are determined. These reactions should have a negligible reverse activation barrier; therefore, E(o) values should be approximately equal to the binding energy or hydration enthalpy at 0 K. For the hepta- and hexahydrated ions at low temperature, binding energies follow the trend expected on the basis of ionic radii: Mg > Ca > Sr > Ba. For the hexahydrated ions at high temperature, binding energies follow the order Ca > Mg > Sr > Ba. The same order is observed for the pentahydrated ions. Collisional dissociation experiments on the tetrahydrated species result in relative dissociation rates that directly correlate with the size of the metals. These results indicate the presence of two isomers for hexahydrated magnesium ions: a low-temperature isomer in which the six water molecules are located in the first solvation shell, and a high-temperature isomer with the most likely structure corresponding to four water molecules in the inner shell and two water molecules in the second shell. These results also indicate that the pentahydrated magnesium ions have a structure with four water molecules in the first solvation shell and one in the outer shell. The dissociation kinetics for the hexa- and pentahydrated clusters of Ca(2+), Sr(2+), and Ba(2+) are consistent with structures in which all the water molecules are located in the first solvation shell.

  3. Nitrogen transport and transformations in a coastal plain watershed: Influence of geomorphology on flow paths and residence times

    USGS Publications Warehouse

    Tesoriero, Anthony J.; Spruill, Timothy B.; Mew, H.E.; Farrell, Kathleen M.; Harden, Stephen L.

    2005-01-01

    Nitrogen transport and groundwater-surface water interactions were examined in a coastal plain watershed in the southeastern United States. Groundwater age dates, calculated using chlorofluorocarbon and tritium concentrations, along with concentrations of nitrogen species and other redox-active constituents, were used to evaluate the fate and transport of nitrate. Nitrate is stable only in recently recharged (<10 years) water found in the upper few meters of saturated thickness in the upland portion of a surficial aquifer. Groundwater with a residence time between 10 and 30 years typically has low nitrate and elevated excess N2 concentrations, indications that denitrification has reduced nitrate concentrations. Groundwater older than 30 years also has low nitrate concentrations but contains little or no excess N2, suggesting that this water did not contain elevated concentrations of nitrate along its flow path. Nitrate transport to streams varies between first- and third-order streams. Hydrologic, lithologic, and chemical data suggest that the surficial aquifer is the dominant source of flow and nitrate to a first-order stream. Iron-reducing conditions occur in groundwater samples from the bed and banks of the first-order stream, suggesting that direct groundwater discharge is denitrified prior to entering the stream. However, nitrogen from the surficial aquifer is transported directly to the stream via a tile drain that bypasses these reduced zones. In the alluvial valley of a third-order stream the erosion of a confining layer creates a much thicker unconfined alluvial aquifer with larger zones of nitrate stability. Age dating and chemical information (SiO 2, Na/K ratios) suggest that water in the alluvial aquifer is derived from short flow paths through the riparian zone and/or from adjacent streams during high-discharge periods. Copyright 2005 by the American Geophysical Union.

  4. Regulation of water balance in mangroves.

    PubMed

    Reef, Ruth; Lovelock, Catherine E

    2015-02-01

    Mangroves are a group of highly salt-tolerant woody plants. The high water use efficiency of mangroves under saline conditions suggests that regulation of water transport is a crucial component of their salinity tolerance. This review focuses on the processes that contribute to the ability of mangroves to maintain water uptake and limit water loss to the soil and the atmosphere under saline conditions, from micro to macro scales. These processes include: (1) efficient filtering of the incoming water to exclude salt; (2) maintenance of internal osmotic potentials lower than that of the rhizosphere; (3) water-saving properties; and (4) efficient exploitation of less-saline water sources when these become available. Mangroves are inherently plastic and can change their structure at the root, leaf and stand levels in response to salinity in order to exclude salt from the xylem stream, maintain leaf hydraulic conductance, avoid cavitation and regulate water loss (e.g. suberization of roots and alterations of leaf size, succulence and angle, hydraulic anatomy and biomass partitioning). However, much is still unknown about the regulation of water uptake in mangroves, such as how they sense and respond to heterogeneity in root zone salinity, the extent to which they utilize non-stomatally derived CO2 as a water-saving measure and whether they can exploit atmospheric water sources. © The Author 2014. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  5. Water mist injection in oil shale retorting

    DOEpatents

    Galloway, T.R.; Lyczkowski, R.W.; Burnham, A.K.

    1980-07-30

    Water mist is utilized to control the maximum temperature in an oil shale retort during processing. A mist of water droplets is generated and entrained in the combustion supporting gas flowing into the retort in order to distribute the liquid water droplets throughout the retort. The water droplets are vaporized in the retort in order to provide an efficient coolant for temperature control.

  6. Influences of coal mining water irrigation on the maize losses in the Xingdong Mine area, China.

    PubMed

    Sun, Yuzhuang; Ling, Pei; Li, Yanheng; Li, Qingxue; Sun, Quande; Wang, Jinxi

    2014-02-01

    In 2008, a maize underproduction disaster occurred in the Xianyu village after irrigation using the coal mining water from the Xingdong Mine, China. This disaster resulted in about 40 hectare maize underproduction and 20 hectare total loss of the maize yields. In order to study the reason, a total of 25 soil, water and plant samples were taken from the study area. These samples were analysed by inductively coupled plasma mass spectrometry and ion chromatography. The results indicate that the contents of both water-soluble fluorine and total fluorine are very high and resulting of maize underproduction and total loss of production. The possible pollution sources of fluorine in the study area could be from the coal mine water used for irrigation and glass chemical factory near the study area.

  7. Isotopic and chemical composition of parbati valley geothermal discharges, North-West Himalaya, India

    USGS Publications Warehouse

    Giggenbach, W.F.; Gonfiantini, R.; Jangi, B.L.; Truesdell, A.H.

    1983-01-01

    The isotopic compositions of the waters discharged from Parbati Valley geothermal areas indicate a higher altitude meteoric origin, with discharge temperatures reflecting variations in the depth of penetration of the waters to levels heated by the existence of a 'normal' geothermal gradient. On the basis of mixing models involving silica, tritium, discharge temperatures and chloride contents, deep equilibration temperatures of 120-140??C were obtained for Manikaran, possibly reaching 160??C at even greater depth. Geothermometers based on sulfate-water 18O exchange and gas reactions point to similar temperatures. Exceptionally high helium contents of the discharges correspond to apparent crustal residence times of the waters in the order of 10-100 Ma; relative nitrogen-argon contents support a largely meteoric origin of the waters with a possible fossil brine, but no detectable magmatic component. ?? 1983.

  8. Biogeochemical response of organic-rich freshwater marshes in the Louisiana delta plain to chronic river water influx

    USGS Publications Warehouse

    Swarzenski, C.M.; Doyle, T.W.; Fry, B.; Hargis, T.G.

    2008-01-01

    To help evaluate effects of Mississippi River inputs to sustainability of coastal Louisiana ecosystems, we compared porewater and substrate quality of organic-rich Panicum hemitomon freshwater marshes inundated by river water annually for more than 30 years (Penchant basin, PB) or not during the same time (Barataria basin, BB). In the marshes receiving river water the soil environment was more reduced, the organic substrate was more decomposed and accumulated more sulfur. The porewater dissolved ammonium and orthophosphate concentrations were an order of magnitude higher and sulfide and alkalinity concentrations were more than twice as high in PB compared with BB marshes. The pH was higher and dissolved iron concentrations were more than an order of magnitude lower in PB marshes than in BB marshes. The influx of nutrient-rich river water did not enhance end-of-year above-ground standing biomass or vertical accretion rates of the shallow substrate. The differences in porewater chemistry and substrate quality are reasonably linked to the long-term influx of river water through biogeochemical processes and transformations involving alkalinity, nitrate and sulfate. The key factor is the continual replenishment of alkalinity, nitrate and sulfate via overland flow during high river stage each year for several weeks to more than 6 months. This leads to a reducing soil environment, pooling of the phytotoxin sulfide and inorganic nutrients in porewater, and internally generated alkalinity. Organic matter decomposition is enhanced under these conditions and root mats degraded. The more decomposed root mat makes these marshes more susceptible to erosion during infrequent high-energy events (for example hurricanes) and regular low-energy events, such as tides and the passage of weather fronts. Our findings were unexpected and, if generally applicable, suggest that river diversions may not be the beneficial mitigating agent of wetland restoration and conservation that they are anticipated to be. ?? 2008 Springer Science+Business Media B.V.

  9. Pesticides and biocides in a karst catchment: Identification of contaminant sources and related flow components

    NASA Astrophysics Data System (ADS)

    Wagner, Thomas; Bollmann, Ulla E.; Bester, Kai; Birk, Steffen

    2013-04-01

    Karst aquifers are widely used as drinking water resources. However, their high vulnerability to chemical and bacterial contamination due to the heterogeneity in aquifer properties (highly conductive solution conduits embedded in the less conductive fissured rock) is difficult to assess and thus poses major challenges to the management of karst water resources. Contamination of karst springs by organic micro-pollutants has been observed in recent studies. Within this study the water from different springs draining one karst aquifer as well as the main sinking stream replenishing it were analysed before, during and after a storm water event in order to examine the occurrence of different pesticides and biocides. Contaminants from both urban as well as agricultural origin could be detected in the water with concentrations in the low ng/L range (tebuconazole, carbendazim, diuron, isoproturon, terbutryn, atrazine, dichlorobenzamide (BAM), which is a metabolite of dichlobenil). While some compounds could be followed from the sinking stream to the springs (e.g. dichlorobenzamide) some seem to have a source in the autogenic recharge from the karst plateau (Tebuconazole: wood preservative in buildings). These compounds appear to be related to fast flow components with residence times in the order of days, which are known from a number of tracer tests with fluorescent dyes. However, the occurrence of the pesticide atrazine (banned since 1995 in Austria) in the springs, while on the other hand no current input into the karst occurs, shows that some compounds have long residence times in the karst aquifer. These differences in residence times can hardly be attributed to differences in physico-chemical properties of the compounds and must thus be due to the presence of slow and fast flow components. This is in agreement with the duality of karst aquifers due to highly conductive networks of solution conduits embedded in less conductive fissured carbonate rocks.

  10. Survival and growth of salmonella in high-moisture pecan nutmeats, in-shell pecans, inedible nut components, and orchard soil.

    PubMed

    Beuchat, Larry R; Mann, David A

    2010-11-01

    Outbreaks of salmonellosis associated with almonds have raised interest in better understanding the behavior of Salmonella on other tree nuts. We undertook a study to determine the survival and growth characteristics of Salmonella on high-moisture (water activity of 0.96 to 0.99) pecan nutmeats, in-shell pecans, and inedible components (shuck, shell, and middle septum tissue) of in-shell pecans. Salmonella did not grow on high-moisture nutmeat halves, pieces, or granules stored at 4°C for up to 48 h. Growth did occur, however, at 21, 30, and 37°C. Increases of 1.77 to 5.87 log CFU/g of nutmeats occurred within 48 h at 37°C; the order in which nutmeats supported growth was granules > pieces > halves. Populations of Salmonella on and in high-moisture in-shell pecans (kernel water activity of 0.94) stored at 4, 21, 30, and 37°C for 8 days decreased by 0.52 to 1.19 log CFU/g. The pathogen grew on the surface of high-moisture (water activity of 0.99) pecan shucks and shells but died on middle septum tissue stored at 21, 30, and 37°C for up to 6 days. Salmonella died in water extracts of shucks and in pecan orchard soil saturated with water or shuck extract, but survived well for at least 18 weeks in dry soil. The ability of the pathogen to grow on high-moisture nutmeats and some of the inedible components of pecans emphasizes the importance of controlling or limiting the time pecans are exposed to water in preharvest and postharvest environments.

  11. The Imbalance between Nature and Management: Jurisdictional Evaluation of Headwaters in a Mountain Watershed (Invited)

    NASA Astrophysics Data System (ADS)

    Caruso, B. S.

    2013-12-01

    In mountain ecoregions of the semi-arid western U.S., there is an imbalance between science and policy for jurisdictional determinations of aquatic resource as ';waters of the US' that can be protected under Clean Water Act Section 404 (permitting discharge of dredged and fill materials into wetlands and other waters). This leads to continued degradation of surface waters due to the imbalance of key biophysical and societal/regulatory components; the imbalance of water across these drier landscapes, and the imbalance between the critical ecological services provided by these headwater areas and the increasing impacts from urbanization and energy development in previously undeveloped areas. This study analysed headwater streams in a mountain watershed in southwestern Colorado and developed a classification scheme and hydrological connectivity index to demonstrate jurisdictional evaluation at a watershed scale. The National Hydrography Dataset and USGS program StreamStats were used with field observations to classify flow duration and stream order used for Level 1 and 2 classification. Kruskall Wallis tests and discriminant analysis were used to evaluate differences among Level 1 and 2 classes. Hierarchical cluster analysis was used to develop Level 3 classes based on stream length, distance to the nearest downstream traditional navigable water (TNW), and the ratio of mean annual flow from the source stream to the TNW. Three primary metrics were used for HCI development: Avg Q/AQ, or the average streamflow metric as a proportion of the metric for the TNW, distance from the stream to the TNW, and slope to the TNW. Additional metrics were also analyzed including stream length, elevation, channel slope and type, and riparian zone types. Perennial waters constitute over a third of all streams (the highest order of which is 4th order), 64% of all reaches are intermittent or ephemeral, and almost half are ephemeral 1st order (E1). The perennial and intermittent streams are classified as jurisdictional relatively permanent waters (RPWs). All ephemeral reaches are non-RPWs and would require significant nexus evaluation to determine jurisdiction. The main stream contributes 20% of the average annual flow to the TNW, and 5% of the total to the river can come from E1 streams. There were significant differences in most metrics among Level 2 classes. There was a large range of HCI values, with 48% <1 for ephemeral streams that are not RPWs requiring a significant nexus evaluation to determine jurisdiction. Perennial streams, ponds and intermittent streams that are jurisdictional RPWs had HCI values >1. Mean values differed among stream duration and order classes. Many ephemeral streams may be non-jurisdictional and unprotected under Section 404 of the Clean Water Act. The flow index (QI) component constituted the greatest proportion of the HCI for perennial streams, was sensitive to the Q metrics used, and was greatest for high flows. Ephemeral streams are only connected to the TNW <3 months of the year, but their flow contribution is proportionally larger during high flows than other flow metrics. Streams in one ephemeral Level 3 class with HCI values from 0.75-0.94 are farthest from the TNW but contribute the greatest proportion of flow and may have significant nexus with the river.

  12. Extraction of organic materials from red water by metal-impregnated lignite activated carbon.

    PubMed

    Wei, Fangfang; Zhang, Yihe; Lv, Fengzhu; Chu, Paul K; Ye, Zhengfang

    2011-12-15

    Extraction of organic materials from 2,4,6-trinitrotoluene (TNT) red water by lignite activated carbon (LAC) impregnated with Cu(2+), Ba(2+), Sn(2+), Fe(3+), Ca(2+) and Ag(+) was investigated. The affinity to organic materials in red water was found to follow the order: Cu/LAC>Sn/LAC>Ag/LAC>Ba/LAC>Fe/LAC>Ca/LAC, which was explained by the hard and soft acid base (HSAB) theory. Cu(2+) showed the best performance and several parameters were further studied. X-ray photoelectron spectroscopy (XPS) verified effective loading of Cu(2+) on the LAC surface. The water quality before and after treated by Cu/LAC was evaluated using high performance liquid chromatograph, Gas Chromatography/Mass Spectroscopy (GC/MS), UV-vis spectroscopy and other analyses. The extraction performances and mechanism of organic materials on Cu/LAC were investigated through static methods. The experimental results showed that Cu/LAC possessed stronger extraction ability for the sulfonated nitrotoluenes than the non-sulfonated nitrotoluenes, the kinetic data fitted the pseudo-second-order kinetic model well. In addition, the leaching out of Cu(2+) from Cu/LAC was found much lower in the 100 times diluted red water (0.074%) than in the raw water (10.201%). Column adsorptions with more concentrated red water were also studied. Finally, Cu/LAC was observed to possess excellent reusability as well. Copyright © 2011 Elsevier B.V. All rights reserved.

  13. New chlorinated amphetamine-type-stimulants disinfection-by-products formed during drinking water treatment.

    PubMed

    Huerta-Fontela, Maria; Pineda, Oriol; Ventura, Francesc; Galceran, Maria Teresa

    2012-06-15

    Previous studies have demonstrated high removal rates of amphetamine-type-stimulants (ATSs) through conventional drinking water treatments; however the behaviour of these compounds through disinfection steps and their transformation into disinfection-by-products (DBPs) is still unknown. In this work, for the first time, the reactivity of some ATSs such as amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA) and 3,4-methylenedioxyethylamphetamine (MDEA) with chlorine has been investigated under simulated and real drinking water treatment conditions in order to evaluate their ability to give rise to transformation products. Two new DBPs from these illicit drugs have been found. A common chlorinated-by-product (3-chlorobenzo)-1,3-dioxole, was identified for both MDA and MDEA while for MDMA, 3-chlorocatechol was found. The presence of these DBPs in water samples collected through drinking water treatment was studied in order to evaluate their formation under real conditions. Both compounds were generated through treatment from raw river water samples containing ATSs at concentration levels ranging from 1 to 15 ng/L for MDA and from 2.3 to 78 ng/L for MDMA. One of them, (3-chlorobenzo)-1,3-dioxole, found after the first chlorination step, was eliminated after ozone and GAC treatment while the MDMA DBP mainly generated after the postchlorination step, showed to be recalcitrant and it was found in final treated waters at concentrations ranging from 0.5 to 5.8 ng/L. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. The energy cost of water independence: the case of Singapore.

    PubMed

    Vincent, Lenouvel; Michel, Lafforgue; Catherine, Chevauché; Pauline, Rhétoré

    2014-01-01

    Finding alternative resources to secure or increase water availability is a key issue in most urban areas. This makes the research of alternative and local water resources of increasing importance. In the context of political tension with its main water provider (Malaysia), Singapore has been implementing a comprehensive water policy for some decades, which relies on water demand management and local water resource mobilisation in order to reach water self-sufficiency by 2060. The production of water from alternative resources through seawater desalination or water reclamation implies energy consumptive technologies such as reverse osmosis. In the context of increasing energy costs and high primary energy dependency, this water self-sufficiency objective is likely to be an important challenge for Singapore. The aim of this paper is to quantify the long-term impact of Singapore's water policy on the national electricity bill and to investigate the impact of Singapore's projects to reduce its water energy footprint. We estimate that 2.0% of the Singaporean electricity demand is already dedicated to water and wastewater treatment processes. If its water-energy footprint dramatically increases in the coming decades, ambitious research projects may buffer the energy cost of water self-sufficiency.

  15. Contribution of atmospheric nitrate to stream-water nitrate in Japanese coniferous forests revealed by the oxygen isotope ratio of nitrate.

    PubMed

    Tobari, Y; Koba, K; Fukushima, K; Tokuchi, N; Ohte, N; Tateno, R; Toyoda, S; Yoshioka, T; Yoshida, N

    2010-05-15

    Evaluation of the openness of the nitrogen (N) cycle in forest ecosystems is important in efforts to improve forest management because the N supply often limits primary production. The use of the oxygen isotope ratio (delta(18)O) of nitrate is a promising approach to determine how effectively atmospheric nitrate can be retained in a forest ecosystem. We investigated the delta(18)O of nitrate in stream water in order to estimate the contribution of atmospheric NO(3) (-) in stream-water NO(3) (-) (f(atm)) from 26 watersheds with different stand ages (1-87 years) in Japan. The stream-water nitrate concentrations were high in young forests whereas, in contrast, old forests discharged low-nitrate stream water. These results implied a low f(atm) and a closed N cycle in older forests. However, the delta(18)O values of nitrate in stream water revealed that f(atm) values were higher in older forests than in younger forests. These results indicated that even in old forests, where the discharged N loss was small, atmospheric nitrate was not retained effectively. The steep slopes of the studied watersheds (>40 degrees ) which hinder the capturing of atmospheric nitrate by plants and microbes might be responsible for the inefficient utilization of atmospheric nitrate. Moreover, the unprocessed fraction of atmospheric nitrate in the stream-water nitrate in the forest (f(unprocessed)) was high in the young forest (78%), although f(unprocessed) was stable and low for other forests (5-13%). This high f(unprocessed) of the young forest indicated that the young forest retained neither atmospheric NO(3) (-) nor soil NO(3) (-) effectively, engendering high stream-water NO(3) (-) concentrations. Copyright (c) 2010 John Wiley & Sons, Ltd.

  16. Contamination of water and soil by the Erdenet copper-molybdenum mine in Mongolia

    NASA Astrophysics Data System (ADS)

    Battogtokh, B.; Lee, J.; Woo, N. C.; Nyamjav, A.

    2013-12-01

    As one of the largest copper-molybdenum (Cu-Mo) mines in the world, the Erdenet Mine in Mongolia has been active since 1978, and is expected to continue operations for at least another 30 years. In this study, the potential impacts of mining activities on the soil and water environments have been evaluated. Water samples showed high concentrations of sulfate, calcium, magnesium, Mo, and arsenic, and high pH values in the order of high to low as follows: tailing water > Khangal River > groundwater. Statistical analysis and the δ2H and δ18O values of water samples indicate that the tailing water directly affects the stream water and indirectly affects groundwater through recharge processes. Soil and stream sediments are highly contaminated with Cu and Mo, which are major elements of ore minerals. Based on the contamination factor (CF), the pollution load index (PLI), and the degree of contamination (Cd), soil appears to be less contaminated than stream sediments. The soil particle size is similar to that of tailing materials, but stream sediments have much coarser particles, implying that the materials have different origins. Contamination levels in stream sediments display a tendency to decrease with distance from the mine, but no such changes are found in soil. Consequently, soil contamination by metals is attributable to wind-blown dusts from the tailing materials, and stream sediment contamination is caused by discharges from uncontained subgrade ore stock materials. Considering the evident impact on the soil and water environment, and the human health risk from the Erdenet Mine, measures to mitigate its environmental impact should be taken immediately including source control, the establishment of a systematic and continuous monitoring system, and a comprehensive risk assessment. Sampling locations around the Erdenet Mine

  17. Apparent optical properties of the Canadian Beaufort Sea - Part 1: Observational overview and water column relationships

    NASA Astrophysics Data System (ADS)

    Antoine, D.; Hooker, S. B.; Bélanger, S.; Matsuoka, A.; Babin, M.

    2013-07-01

    A data set of radiometric measurements collected in the Beaufort Sea (Canadian Arctic) in August 2009 (Malina project) is analyzed in order to describe apparent optical properties (AOPs) in this sea, which has been subject to dramatic environmental changes for several decades. The two properties derived from the measurements are the spectral diffuse attenuation coefficient for downward irradiance, Kd, and the spectral remote sensing reflectance, Rrs. The former controls light propagation in the upper water column. The latter determines how light is backscattered out of the water and becomes eventually observable from a satellite ocean color sensor. The data set includes offshore clear waters of the Beaufort Basin as well as highly turbid waters of the Mackenzie River plumes. In the clear waters, we show Kd values that are much larger in the ultraviolet and blue parts of the spectrum than what could be anticipated considering the chlorophyll concentration. A larger contribution of absorption by colored dissolved organic matter (CDOM) is responsible for these high Kd values, as compared to other oligotrophic areas. In turbid waters, attenuation reaches extremely high values, driven by high loads of particulate materials and also by a large CDOM content. In these two extreme types of waters, current satellite chlorophyll algorithms fail. This questions the role of ocean color remote sensing in the Arctic when Rrs from only the blue and green bands are used. Therefore, other parts of the spectrum (e.g., the red) should be explored if one aims at quantifying interannual changes in chlorophyll in the Arctic from space. The very peculiar AOPs in the Beaufort Sea also advocate for developing specific light propagation models when attempting to predict light availability for photosynthesis at depth.

  18. Apparent optical properties of the Canadian Beaufort Sea - Part 1: Observational overview and water column relationships

    NASA Astrophysics Data System (ADS)

    Antoine, D.; Hooker, S. B.; Belanger, S.; Matsuoka, A.; Babin, M.

    2013-03-01

    A data set of radiometric measurements collected in the Beaufort Sea (Canadian Arctic) in August 2009 (MALINA project) is analysed in order to describe apparent optical properties (AOPs) in this sea, which is subject to dramatic environmental changes for several decades. The two properties derived from the measurements are the spectral diffuse attenuation coefficient for downward irradiance, Kd, and the spectral remote sensing reflectance, Rrs. The former controls light propagation in the upper water column. The latter determines how light is backscattered out of the water and becomes eventually observable from a satellite ocean colour sensor. The data set includes offshore clear waters of the Beaufort basin as well as highly turbid waters of the Mackenzie River plumes. In the clear waters, we show Kd values that are much larger in the ultraviolet and blue parts of the spectrum than what could be anticipated considering the chlorophyll concentration. A larger contribution of absorption by coloured dissolved organic matter (CDOM) is responsible for this high Kd values, as compared to other oligotrophic areas. In turbid waters, attenuation reaches extremely high values, driven by high loads of particulate materials and also by a large CDOM content. In these two extreme types of waters, current satellite chlorophyll algorithms fail. This is questioning the role of ocean colour remote sensing in the Arctic when Rrs from only the blue and green bands are used. Therefore, other parts of the spectrum (e.g. the red) should be explored if one aims at quantifying interannual changes in chlorophyll in the Arctic from space. The very peculiar AOPs in the Beaufort Sea also advocate for developing specific light propagation models when attempting to predict light availability for photosynthesis at depth.

  19. Laser velocimeter measurements of the flow downstream of the Space Shuttle Main Engine high pressure oxidizer turbopump first-stage turbine nozzle

    NASA Technical Reports Server (NTRS)

    Ferguson, T. V.; Havskjold, G. L.; Rojas, L.

    1988-01-01

    A laser two-focus velocimeter was used in an open-loop water test facility in order to map the flowfield downstream of the SSME's high-pressure oxidizer turbopump first-stage turbine nozzle; attention was given to the effects of the upstream strut-downstream nozzle configuration on the flow at the rotor inlet, in order to estimate dynamic loads on the first-stage rotor blades. Velocity and flow angles were plotted as a function of circumferential position, and were found to clearly display the periodic behavior of the wake flow field. The influence of the upstream centerbody-supporting struts on the vane nozzle wake pattern was evident.

  20. Water Contaminant Mitigation in Ionic Liquid Propellant

    NASA Technical Reports Server (NTRS)

    Conroy, David; Ziemer, John

    2009-01-01

    Appropriate system and operational requirements are needed in order to ensure mission success without unnecessary cost. Purity requirements applied to thruster propellants may flow down to materials and operations as well as the propellant preparation itself. Colloid electrospray thrusters function by applying a large potential to a room temperature liquid propellant (such as an ionic liquid), inducing formation of a Taylor cone. Ions and droplets are ejected from the Taylor cone and accelerated through a strong electric field. Electrospray thrusters are highly efficient, precise, scaleable, and demonstrate low thrust noise. Ionic liquid propellants have excellent properties for use as electrospray propellants, but can be hampered by impurities, owing to their solvent capabilities. Of foremost concern is the water content, which can result from exposure to atmosphere. Even hydrophobic ionic liquids have been shown to absorb water from the air. In order to mitigate the risks of bubble formation in feed systems caused by water content of the ionic liquid propellant, physical properties of the ionic liquid EMI-Im are analyzed. The effects of surface tension, material wetting, physisorption, and geometric details of the flow manifold and electrospray emitters are explored. Results are compared to laboratory test data.

  1. Phosphorus sorption and buffering mechanisms in suspended sediments from the Yangtze Estuary and Hangzhou Bay, China

    NASA Astrophysics Data System (ADS)

    Li, M.; Whelan, M. J.; Wang, G.; White, S. M.

    2012-12-01

    The adsorption isotherm and the mechanism of the buffering effect are important controls on phosphorus behaviors in estuaries and are important for estimating phosphate concentrations in aquatic environments. In this paper, we derive phosphate adsorption isotherms in order to investigate sediment adsorption and buffering capacity for phosphorus discharged from sewage outfalls in the Yangtze Estuary and Hangzhou Bay near Shanghai, China. Experiments were also carried out at different temperatures in order to explore the buffering effects for phosphate. The results show that P sorption in sediments with low fine particle fractions was best described using exponential equations. Some P interactions between water and sediment may be caused by the precipitation of CaHPO4 from Ca2+ and HPO42- when the phosphate concentration in the liquid phase is high. Results from the buffering experiments suggest that the Zero Equilibrium Phosphate Concentrations (EPC0) vary from 0.014 mg l-1 to 0.061 mg l-1, which are consistent with measured phosphate concentrations in water samples collected at the same time as sediment sampling. Values of EPC0 and linear sorption coefficients (K) in sediments with high fine particle and organic matter contents are relatively high, which implies that they have high buffering capacity. Both EPC0 and K increase with increasing temperature, indicating a higher P buffering capacity at high temperatures.

  2. Phosphorus sorption and buffering mechanisms in suspended sediments from the Yangtze Estuary and Hangzhou Bay, China

    NASA Astrophysics Data System (ADS)

    Li, M.; Whelan, M. J.; Wang, G. Q.; White, S. M.

    2013-05-01

    The adsorption isotherm and the mechanism of the buffering effect are important controls on phosphorus (P) behaviors in estuaries and are important for estimating phosphate concentrations in aquatic environments. In this paper, we derive phosphate adsorption isotherms in order to investigate sediment adsorption and buffering capacity for phosphorus discharged from sewage outfalls in the Yangtze Estuary and Hangzhou Bay near Shanghai, China. Experiments were also carried out at different temperatures in order to explore the buffering effects for phosphate. The results show that P sorption in sediments with low fine particle fractions was best described using exponential equations. Some P interactions between water and sediment may be caused by the precipitation of CaHPO4 from Ca2+ and HPO42- when the phosphate concentration in the liquid phase is high. Results from the buffering experiments suggest that the Zero Equilibrium Phosphate Concentrations (EPC0) vary from 0.014 mg L-1 to 0.061 mg L-1, which are consistent with measured phosphate concentrations in water samples collected at the same time as sediment sampling. Values of EPC0 and linear sorption coefficients (K) in sediments with high fine particle and organic matter contents are relatively high, which implies that they have high buffering capacity. Both EPC0 and K increase with increasing temperature, indicating a higher P buffering capacity at high temperatures.

  3. Water ordering controls the dynamic equilibrium of micelle-fibre formation in self-assembly of peptide amphiphiles.

    PubMed

    Deshmukh, Sanket A; Solomon, Lee A; Kamath, Ganesh; Fry, H Christopher; Sankaranarayanan, Subramanian K R S

    2016-08-24

    Understanding the role of water in governing the kinetics of the self-assembly processes of amphiphilic peptides remains elusive. Here, we use a multistage atomistic-coarse-grained approach, complemented by circular dichroism/infrared spectroscopy and dynamic light scattering experiments to highlight the dual nature of water in driving the self-assembly of peptide amphiphiles (PAs). We show computationally that water cage formation and breakage near the hydrophobic groups control the fusion dynamics and aggregation of PAs in the micellar stage. Simulations also suggest that enhanced structural ordering of vicinal water near the hydrophilic amino acids shifts the equilibrium towards the fibre phase and stimulates structure and order during the PA assembly into nanofibres. Experiments validate our simulation findings; the measured infrared O-H bond stretching frequency is reminiscent of an ice-like bond which suggests that the solvated water becomes increasingly ordered with time in the assembled peptide network, thus shedding light on the role of water in a self-assembly process.

  4. Sensitivity of high-elevation streams in the Southern Blue Ridge Province to acidic deposition

    USGS Publications Warehouse

    Winger, P.V.; Lasier, P.J.; Hudy, M.; Fowler, D.; Van Den Avyle, M.J.

    1987-01-01

    The Southern Blue Ridge Province, which encompasses parts of northern Georgia, eastern Tennessee, and western North Carolina, has been predicted to be sensitive to impacts from acidic deposition, owing to the chemical composition of the bedrock geology and soils. This study confirms the predicted potential sensitivity, quantifies the level of total alkalinity and describes the chemical characteristics of 30 headwater streams of this area. Water chemistry was measured five times between April 1983 and June 1984 at first and third order reaches of each stream during baseflow conditions. Sensitivity based on total alkalinity and the Calcite Saturation Index indicates that the headwater streams of the Province are vulnerable to acidification. Total alkalinity and p11 were generally higher in third order reaches (mean, 72 ?eq/? and 6.7) than in first order reaches (64 ?eq/? and 6.4). Ionic concentrations were low, averaging 310 and 340 ?eq/? in first and third order reaches, respectively. A single sampling appears adequate for evaluating sensitivity based on total alkalinity, but large temporal variability requires multiple sampling for the detection of changes in pH and alkalinity over time. Monitoring of stream water should continue in order to detect any subtle effects of acidic deposition on these unique resource systems.

  5. Gold nanoparticle-based simple colorimetric and ultrasensitive dynamic light scattering assay for the selective detection of Pb(II) from paints, plastics, and water samples.

    PubMed

    Beqa, Lule; Singh, Anant Kumar; Khan, Sadia Afrin; Senapati, Dulal; Arumugam, Sri Ranjini; Ray, Paresh Chandra

    2011-03-01

    Pb (II) is a common water pollutant with high toxicity. According to the CDC, about 310,000 U.S. children of ages 1-5 have high levels of lead in their blood that it is due to the exposure to lead from plastic toys and other products. As a result, the development of ultrasensitive assays for the real-time detection of Pb(II) from plastic toys and paints is very important for water controlling, clinical toxicology and industrial processes. Driven by the need to detect trace amounts of Pb(II) from water samples, we report a label-free, highly selective and ultra sensitive glutathione modified gold nanoparticle based dynamic light scattering (DLS) probe for Pb(II) recognition in 100 ppt level from aqueous solution with excellent discrimination against other heavy metals. The sensitivity of our assay to detect Pb(II) level in water is almost 2 orders of magnitude higher than the EPA standard limit. We have also demonstrated that our DLS assay is capable of measuring the amount of Pb(II) in paint, plastic toys, and water from MS river. A possible mechanism and operating principles of our DLS assay have been discussed. Ultimately, this nanotechnology driven assay could have enormous potential applications in rapid, on-site monitoring of Pb(II) from day-to-day sample.

  6. Insights from fumarole gas geochemistry on the origin of hydrothermal fluids on the Yellowstone Plateau

    USGS Publications Warehouse

    Chiodini, Giovanni; Caliro, Stefano; Lowenstern, Jacob B.; Evans, William C.; Bergfeld, D.; Tassi, Franco; Tedesco, Dario

    2012-01-01

    The chemistry of Yellowstone fumarole gases shows the existence of two component waters, type MC, influenced by the addition of deep mantle fluid, and type CC, influenced by crustal interactions (CC). MC is high in 3He/4He (22 Ra) and low in 4He/40Ar (~1), reflecting input of deep mantle components. The other water is characterized by 4He concentrations 3-4 orders of magnitude higher than air-saturated meteoric water (ASW). These high He concentrations originate through circulation in Pleistocene volcanic rocks, as well as outgassing of Tertiary and older (including Archean) basement, some of which could be particularly rich in uranium, a major 4He source. Consideration of CO2-CH4-CO-H2O-H2 gas equilibrium reactions indicates equilibration temperatures from 170 °C to 310 °C. The estimated temperatures highly correlate with noble-gas variations, suggesting that the two waters differ in temperature. Type CC is ~170 °C whereas the MC is hotter, at 340 °C. This result is similar to models proposed by previous studies of thermal water chemistry. However, instead of mixing the deep hot component simply with cold, meteoric waters we argue that addition of a 4He-rich component, equilibrated at temperatures around 170 °C, is necessary to explain the range in fumarole gas chemistry.

  7. Modeling two-phase flow in three-dimensional complex flow-fields of proton exchange membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Kim, Jinyong; Luo, Gang; Wang, Chao-Yang

    2017-10-01

    3D fine-mesh flow-fields recently developed by Toyota Mirai improved water management and mass transport in proton exchange membrane (PEM) fuel cell stacks, suggesting their potential value for robust and high-power PEM fuel cell stack performance. In such complex flow-fields, Forchheimer's inertial effect is dominant at high current density. In this work, a two-phase flow model of 3D complex flow-fields of PEMFCs is developed by accounting for Forchheimer's inertial effect, for the first time, to elucidate the underlying mechanism of liquid water behavior and mass transport inside 3D complex flow-fields and their adjacent gas diffusion layers (GDL). It is found that Forchheimer's inertial effect enhances liquid water removal from flow-fields and adds additional flow resistance around baffles, which improves interfacial liquid water and mass transport. As a result, substantial improvements in high current density cell performance and operational stability are expected in PEMFCs with 3D complex flow-fields, compared to PEMFCs with conventional flow-fields. Higher current density operation required to further reduce PEMFC stack cost per kW in the future will necessitate optimizing complex flow-field designs using the present model, in order to efficiently remove a large amount of product water and hence minimize the mass transport voltage loss.

  8. High Resolution Climate Modeling of the Water Cycle over the Western United States Including Potential Climate Change Impacts

    NASA Astrophysics Data System (ADS)

    Rasmussen, R.; Liu, C.; Ikeda, K.

    2016-12-01

    The NCAR Water System program strives to improve the full representation of the water cycle in both regional and global models. Our previous high-resolution simulations using the WRF model over the Rocky Mountains revealed that proper spatial and temporal depiction of snowfall adequate for water resource and climate change purposes can be achieved with the appropriate choice of model grid spacing (< 6 km horizontal) and parameterizations. The climate sensitivity experiment consistent with expected climate change showed an altered hydrological cycle with increased fraction of rain versus snow, increased snowfall at high altitudes, earlier melting of snowpack, and decreased total runoff. In order to investigate regional differences between the Rockies and other major mountain barriers and to study climate change impacts over other regions of the contiguous U.S. (CONUS), we have expanded our prior CO Headwaters modeling study to encompass most of North America at a horizontal grid spacing of 4 km (see figure below). A domain expansion provides the opportunity to assess changes in orographic precipitation across different mountain ranges in the western USA. This study will examine the water cycle over Western U.S. seven U.S. mountain ranges, including likely changes to amount of snowpack and spring melt-off, critical to agriculture in the western U.S.

  9. Kiel Canal: Past and future threats for shipping resulting from precipitation, wind surge and sea level rise

    NASA Astrophysics Data System (ADS)

    Ganske, Anette; Hüttl-Kabus, Sabine; Möller, Jens; Schade, Nils; Heinrich, Hartmut; Tinz, Birger

    2017-04-01

    The Kiel Canal is the most frequented artificial waterway in the world. It connects the North Sea and the Hamburg Harbor with the Baltic Sea and has a length of about 100 km. The Canal receives its water from the upper catchment of the river Eider. Discharge from the Canal towards the North Sea is via the sluices at Brunsbüttel (90%) into river Elbe and into the Baltic Sea via the sluices at Kiel-Holtenau. A risk of closure of the Canal occurs when high precipitation in the catchment meets high water levels in the river Elbe and/or the Baltic preventing the discharge of excess Canal water. Future sea level rise jointly with other effects such as possibly increasing wind surge and precipitation will close the gap between the inner and outer water levels, so that someday the outside levels will surmount the inner one. The German Federal Ministry of Transport and Digital Infrastructure (BMVI) tasked its internal Network of Experts to run a case study on the evolution of critical water levels in order to estimate risks and vulnerabilities for adaptation measures. First step of the investigation is a search for factors or combination of factors responsible for closures in the past. Candidates are factors such as higher water levels at low tides, high precipitation events on land, soil moisture and human factors like preventive water management measures. Second step will be the search for the natural criteria in climate projections. Here we report on the results of the first step of the case study with a focus on the exit towards the North Sea. There, discharge is possible only during low tide. Presently still sufficient difference in height exists between the levels in the Canal and the river Elbe allowing for a free flow of excess Canal water. Shipping is ceased when levels in the Canal surpass safety limits due to high precipitation events in the catchment jointly with high outer water levels. We used atmospheric data from ERA-Interim reanalysis instead of gauge data for reconstructing the history in order to provide metrics that in the second step can be searched in Atmosphere Regional Climate Model runs. Water levels at Brunsbüttel were determined with hourly resolution using atmospheric conditions and astronomical tide. Ocean Model results were and will be excluded because of the small number of runs with astronomical tides and sufficient resolution. Past inflow from the tributary rivers into the Canal was simulated via antecedent and event precipitation derived from the REGNIE data set. Finally, the potential of critical situations in the past was calculated by combining both results and compared their occurrences with the recordings of the responsible waterway authority. In the second step we will analyze the proxies elaborated in step one in regional climate projections and combine them with expected changes of the sea levels in the North and Baltic Seas.

  10. Screening high-fluoride and high-arsenic drinking waters and surveying endemic fluorosis and arsenism in Shaanxi province in western China.

    PubMed

    Zhu, Cansheng; Bai, Guanglu; Liu, Xiaoli; Li, Yue

    2006-09-01

    The objectives of this study were to screen high-fluoride and high-arsenic drinking waters, to evaluate the effectiveness of fluoride-reducing projects and to assess the present condition of endemic fluorosis and arsenism in Shaanxi province in western China. For screening high-fluoride drinking waters, five water samples were collected from each selected village where dental fluorosis patients were detected in 8-12 year-old children. For evaluating the effectiveness of fluoride-reducing projects, four water samples were collected from each project at end-user level. Fluoride concentrations in water samples were measured by fluoride-selective electrode method or spectrophotometry. Dental fluorosis in children aging 8-12 years was examined according to Horowitz's Tooth Surface Index of Fluorosis. Skeletal fluorosis in adults was detected clinically and radiologically according to Chinese Criteria of Clinical Diagnosis of Skeletal Fluorosis. For screening high-arsenic waters, 20 water samples were collected from each village which was selected from areas characterized by the geographic features to induce high-arsenic underground water, i.e., alluvial plains, ore mining or smelting areas, geothermal artesians, and thermal springs. Arsenic concentrations in water samples were determined by spectrophotometry or arsine generation atomic fluorospectrophotometry. Arsenism in adults aging 40-89 years was examined in villages with arsenic concentrations in drinking water above 0.05 mg/l according to Chinese Criteria for Classification of Endemic Arsenism Areas and Clinical Diagnoses of Endemic Arsenism. The results showed that the fluoride level of 7144 water samples was 1.17 +/- 0.93 mg/l. There were 3396 (47.6%) high-fluoride waters (fluoride level was above 1.0 mg/l) distributing in 786 (45.1%) villages, where about 0.8 million (50.0%) people inhabited. Additionally, the 1315 fluoride-reducing projects were studied. The fluoride level of the projects was 2.79 +/- 1.09 and 0.98 +/- 0.47 mg/l before and after building the projects, which remained at relatively lower level (1.03 +/- 0.47 mg/l). But there were still 58.0% of the projects providing drinking waters with fluoride concentrations beyond 1.0mg/l. The rates of dental fluorosis and skeletal fluorosis were 38.2% and 11.8%, respectively. The arsenic level of 1732 water samples was 0.010 +/- 0.082 mg/l. There were 174 (14.9%) high-arsenic waters (arsenic level was above 0.010 mg/l) being detected, distributing in 41 (38.7%) villages. The arsenic level in 53 (4.5%) water samples was beyond 0.025 mg/l. There were 3 villages with arsenic level in drinking water beyond Chinese National Permissible Limits (0.050 mg/l), and the prevalence rate of arsenism reached 37.0% in these three villages, 3.7%, 22.2%, and 11.1% of subjects suffering from mild, moderate, and severe arsenism, respectively. Conclusively, the wide distribution of high-fluoride drinking waters contributes to the prevalence of dental and skeletal fluorosis in Shaanxi province and the quality of fluoride-reducing projects should be further improved. Ore mining and smelting induces high-arsenic drinking waters, resulting in arsenism prevalence in Shang-luo city. Proper measures should be taken to deal with water pollution in the ore mining and smelting areas in order to solve the high-arsenic water problem in Shaanxi province.

  11. Experimental Investigations of Boron, Lithium, and Halogens During High-Temperature Water-Rock Interaction: Insights into the Yellowstone Hydrothermal System

    NASA Astrophysics Data System (ADS)

    Cullen, J. T.; Hurwitz, S.; Thordsen, J. J.; Barnes, J.

    2017-12-01

    B, Li, and halogens (Cl, F, Br) are used extensively in studies of thermal waters to infer fluid equilibrium conditions with the host reservoir lithology, and quantify the possible fraction of a magmatic component in thermal waters. Apart from fluorine, the limited number of minerals that incorporate these elements support the notion that they preferentially partition into an aqueous fluid during high temperature water-rock interaction. Although limited experimental work is largely consistent with these observations, a rigorous experimental investigation is required to quantify the mobility of these elements under conditions emulating a silicic hydrothermal system. Here we present the results from water-rhyolite interaction batch experiments conducted over a range of temperatures between 150 °C and 350 °C and 250 bar. Powdered obsidian from Yellowstone was reacted with MiliQ water and sampled intermittently throughout the duration of the 90 day experiment. The experimental data show that at temperatures ≤ 200 °C, B, Cl, Br, and Li are not readily leached from the rhyolite, whereas aqueous F- concentration increases by a factor of 3.5 when the temperature was increased from 150 °C to 200 °C. Between 200 °C and 250 °C, B concentration increased by more than an order of magnitude and Cl- concentration increased by a factor of 5. F- concentration increased by a factor of 3. Between 250 °C and 300 °C the opposite trend was observed, in which F- concentration decreased by 60%, Br- concentration increased by a factor of 5, and Cl- and B concentrations increased by more than an order of magnitude. The progressive decrease of aqueous F- at T ≥ 300 °C is likely controlled by precipitation into a fluorine bearing secondary mineral(s). Our experimental results demonstrate that leaching of B, Li, Cl, F, and Br from rhyolite is highly temperature-dependent between 150 °C and 350 °C. These results can provide context to infer the sources of solutes discharged at thermal springs and the subsurface water-rhyolite equilibrium temperatures in the Yellowstone hydrothermal system. Work to characterize the alteration mineralogy and the temperature-dependent stable Cl, Li, and B isotope fractionation is currently ongoing. Keywords: Yellowstone, hydrothermal, halogens, experiments, water-rock interaction

  12. Experimental Investigations of Boron, Lithium, and Halogens During High-Temperature Water-Rock Interaction: Insights into the Yellowstone Hydrothermal System

    NASA Astrophysics Data System (ADS)

    Cullen, J. T.; Hurwitz, S.; Thordsen, J. J.; Barnes, J.

    2016-12-01

    B, Li, and halogens (Cl, F, Br) are used extensively in studies of thermal waters to infer fluid equilibrium conditions with the host reservoir lithology, and quantify the possible fraction of a magmatic component in thermal waters. Apart from fluorine, the limited number of minerals that incorporate these elements support the notion that they preferentially partition into an aqueous fluid during high temperature water-rock interaction. Although limited experimental work is largely consistent with these observations, a rigorous experimental investigation is required to quantify the mobility of these elements under conditions emulating a silicic hydrothermal system. Here we present the results from water-rhyolite interaction batch experiments conducted over a range of temperatures between 150 °C and 350 °C and 250 bar. Powdered obsidian from Yellowstone was reacted with MiliQ water and sampled intermittently throughout the duration of the 90 day experiment. The experimental data show that at temperatures ≤ 200 °C, B, Cl, Br, and Li are not readily leached from the rhyolite, whereas aqueous F- concentration increases by a factor of 3.5 when the temperature was increased from 150 °C to 200 °C. Between 200 °C and 250 °C, B concentration increased by more than an order of magnitude and Cl- concentration increased by a factor of 5. F- concentration increased by a factor of 3. Between 250 °C and 300 °C the opposite trend was observed, in which F- concentration decreased by 60%, Br- concentration increased by a factor of 5, and Cl- and B concentrations increased by more than an order of magnitude. The progressive decrease of aqueous F- at T ≥ 300 °C is likely controlled by precipitation into a fluorine bearing secondary mineral(s). Our experimental results demonstrate that leaching of B, Li, Cl, F, and Br from rhyolite is highly temperature-dependent between 150 °C and 350 °C. These results can provide context to infer the sources of solutes discharged at thermal springs and the subsurface water-rhyolite equilibrium temperatures in the Yellowstone hydrothermal system. Work to characterize the alteration mineralogy and the temperature-dependent stable Cl, Li, and B isotope fractionation is currently ongoing. Keywords: Yellowstone, hydrothermal, halogens, experiments, water-rock interaction

  13. Water disinfection in the mountains - state of the art recommendation paper of the Union Internationale des Associations d'Alpinisme Medical Commission.

    PubMed

    Küpper, Thomas E A H; Schöffl, Volker; Milledge, Jim S

    2009-01-01

    This paper provides the official recommendation of the Union Internationale des Associations d'Alpinisme (UIAA) Medical Commission to manage the problem of safe drinking water. The recommendation was accepted and authorized for publication by the Medical Commission during their annual meeting at Treplice, Tzechia, 2008. Safe water is essential for mountaineers worldwide in order to balance challenges associated with high altitude dehydration. The paper summarizes the advantages and disadvantages of several procedures used to procure safe drinking water in the mountains or at high altitude. Limitations or critical details, which may cause failure of the methods are mentioned systematically. We differentiate between "conventional" methods, which should be preferred because they produce safe water and "improvisation". The latter does not produce safe water but may be used if conventional methods are not available for any reason. They decrease the concentration of pathogenic microorganisms and by this they reduce the risk of enteral infection. Water filtration using a ceramic filter system or chemical disinfection is recommended as a standard method. Boiling water should be avoided because it is too fuel consuming and has the potential to increase deforestation. Generally, with regard to infections by water or food, all mountaineers should be vaccinated against hepatitis A and poliomyelitis in regions where they may be at-risk.

  14. [Effects of supplemental irrigation by measuring soil moisture on water consumption chara-cteristics and radiation utilization in wheat].

    PubMed

    Zhang, Rui; Yu, Zhen Wen; Zhang, Yong Li; Shi, Yu; Zhao, Jun Ye

    2017-03-18

    Field experiments were conducted during 2013-2014 and 2014-2015 winter wheat growing seasons by using Jimai 22 as test material. Five treatments were designed: W 0 (non-irrigation during growth season), W 1 (non-irrigation at overwintering, but irrigated to 65% of field capacity (FC) at jointing and 70% of FC at anthesis in 0-40 cm soil layer), W 2 (irrigated to 70% of FC at overwintering, 65% of FC at jointing and 70% of FC at anthesis in 0-40cm soil layer, respectively) and W 3 (irrigated to 75% of FC at overwintering, 65% of FC at jointing and 70% of FC at anthesis in 0-40cm soil layer, respectively), W 4 (irrigated 60 mm at overwintering, jointing and anthesis stages, respectively). The aim was to clarify the effects of supplemental irrigation on water consumption characteristics and photosynthetically active radiation utilization in wheat. Results showed that the total irrigation amount and its ratio to total water consumption in each treatment were ranked as W 4 ＞W 3 ＞W 2 ＞W 1 ＞W 0 . However, the percentage of water consumption in soil to total water consumption was presented as W 0 ＞W 1 , W 2 ＞W 3 , W 4 . The total water consumption, water consumption from anthesis to maturity were ranked as W 4 ＞W 2 , W 3 ＞W 1 ＞W 0 . The order of photosynthetically active radiation (PAR) capture ratio was W 4 ＞W 2 , W 3 ＞W 1 ＞W 0 , but the order was contrary in PAR reflect ratio among the treatments. The net accumulation of dry matter was ranked as W 4 ＞W 2 ＞W 3 ＞W 1 ＞W 0 in the two growing seasons. During the two winter wheat growing seasons, the grain yield in W 2 was higher than in the other treatments, except W 4 , but the irrigation efficiency and water use efficiency in W 2 were the highest. Concerning both the high-yield and high-water use efficiency in this experiment, the most appropriate irrigation regime was W 2 treatment.

  15. Adsorption, Ordering, and Local Environments of Surfactant-Encapsulated Polyoxometalate Ions Probed at the Air–Water Interface

    DOE PAGES

    Doughty, Benjamin; Yin, Panchao; Ma, Ying-Zhong

    2016-07-23

    The continued development and application of surfactant-encapsulated polyoxometalates (SEPs) relies on understanding the ordering and organization of species at their interface and how these are impacted by the various local environments to which they are exposed. In this paper, we report on the equilibrium properties of two common SEPs adsorbed to the air–water interface and probed with surface-specific vibrational sum-frequency generation (SFG) spectroscopy. These results reveal clear shifts in vibrational band positions, the magnitude of which scales with the charge of the SEP core, which is indicative of a static field effect on the surfactant coating and the associated localmore » chemical environment. This static field also induces ordering in surrounding water molecules that is mediated by charge screening via the surface-bound surfactants. From these SFG measurements, we are able to show that Mo 132-based SEPs are more polar than Mo 72V 30 SEPs. Disorder in the surfactant chain packing at the highly curved SEP surfaces is attributed to large conic volumes that can be sampled without interactions with neighboring chains. Measurements of adsorption isotherms yield free energies of adsorption to the air–water interface of -46.8 ± 0.4 and -44.8 ± 1.2 kJ/mol for the Mo 132 and Mo 72V 30 SEPs, respectively, indicating a strong propensity for the fluid surface. Finally, the influence of intermolecular interactions on the surface adsorption energies is discussed.« less

  16. New analytical solutions to the two-phase water faucet problem

    DOE PAGES

    Zou, Ling; Zhao, Haihua; Zhang, Hongbin

    2016-06-17

    Here, the one-dimensional water faucet problem is one of the classical benchmark problems originally proposed by Ransom to study the two-fluid two-phase flow model. With certain simplifications, such as massless gas phase and no wall and interfacial frictions, analytical solutions had been previously obtained for the transient liquid velocity and void fraction distribution. The water faucet problem and its analytical solutions have been widely used for the purposes of code assessment, benchmark and numerical verifications. In our previous study, the Ransom’s solutions were used for the mesh convergence study of a high-resolution spatial discretization scheme. It was found that, atmore » the steady state, an anticipated second-order spatial accuracy could not be achieved, when compared to the existing Ransom’s analytical solutions. A further investigation showed that the existing analytical solutions do not actually satisfy the commonly used two-fluid single-pressure two-phase flow equations. In this work, we present a new set of analytical solutions of the water faucet problem at the steady state, considering the gas phase density’s effect on pressure distribution. This new set of analytical solutions are used for mesh convergence studies, from which anticipated second-order of accuracy is achieved for the 2nd order spatial discretization scheme. In addition, extended Ransom’s transient solutions for the gas phase velocity and pressure are derived, with the assumption of decoupled liquid and gas pressures. Numerical verifications on the extended Ransom’s solutions are also presented.« less

  17. Widespread occurrence of neonicotinoid insecticides in streams in a high corn and soybean producing region, USA

    USGS Publications Warehouse

    Hladik, Michelle; Kolpin, Dana W.; Kuivila, Kathryn

    2014-01-01

    Neonicotinoid insecticides are of environmental concern, but little is known about their occurrence in surface water. An area of intense corn and soybean production in the Midwestern United States was chosen to study this issue because of the high agricultural use of neonicotinoids via both seed treatments and other forms of application. Water samples were collected from nine stream sites during the 2013 growing season. The results for the 79 water samples documented similar patterns among sites for both frequency of detection and concentration (maximum:median) with clothianidin (75%, 257 ng/L:8.2 ng/L) > thiamethoxam (47%, 185 ng/L: imidacloprid (23%, 42.7 ng/L: <2 ng/L). Neonicotinoids were detected at all nine sites sampled even though the basin areas spanned four orders of magnitude. Temporal patterns in concentrations reveal pulses of neonicotinoids associated with rainfall events during crop planting, suggesting seed treatments as their likely source.

  18. Green synthesis of highly concentrated aqueous colloidal solutions of large starch-stabilised silver nanoplatelets.

    PubMed

    Cheng, Fei; Betts, Jonathan W; Kelly, Stephen M; Hector, Andrew L

    2015-01-01

    A simple, environmentally friendly and cost-effective method has been developed to prepare a range of aqueous silver colloidal solutions, using ascorbic acid as a reducing agent, water-soluble starch as a combined crystallising, stabilising and solubilising agent, and water as the solvent. The diameter of silver nanoplatelets increases with higher concentrations of AgNO3 and starch. The silver nanoparticles are also more uniform in shape the greater the diameter of the nanoparticles. Colloidal solutions with a very high concentration of large, flat, hexagonal silver nanoplatelets (~230 nm in breadth) have been used to deposit and fix an antibacterial coating of these large starch-stabilised silver nanoplates on commercial cotton fibres, using a simple dip-coating process using water as the solvent, in order to study the dependence of the antibacterial properties of these nanoplatelets on their size. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Synergy of VHR Optical and VHR SAR Data for High Resolution DSM Generation over Large Flat Areas: Pleiades and TerraSAR-X Exploitation over the Low Lying Banks of the Yangtze River (PR China)

    NASA Astrophysics Data System (ADS)

    Huber, C.; Studer, M.; Giraud, H.; Durand, A.; Fruteau, L.; Lai, X.; Maxant, J.; Li, F.; Cao, L.; Tinel, C.; Yesou, H.

    2014-11-01

    Water resource monitoring and preservation are some of the biggest issues at global scale, and space technologies are playing a key role in various applications related to water topics the recently launched Sentinel-1, the future Sentinel-2 and 2020 altimetric mission SWOT, will be powerful for an accurate mapping of continental water resources but would be even more powerful and useful in association with high quality Digital Surface Models (DSM). Within the Thematic User Commissioning phase intending to valorize Pleiades imagery, 6 tri-stereo sets of Pleiades-HR images were acquired over test sites located within the Yangtze low-intermediate watershed reaches. At the same time, TanDEM-X InSAR pairs were acquired over the same area in order to get a wider coverage.

  20. Freshwater biodiversity and aquatic insect diversification.

    PubMed

    Dijkstra, Klaas-Douwe B; Monaghan, Michael T; Pauls, Steffen U

    2014-01-01

    Inland waters cover less than 1% of Earth's surface but harbor more than 6% of all insect species: Nearly 100,000 species from 12 orders spend one or more life stages in freshwater. Little is known about how this remarkable diversity arose, although allopatric speciation and ecological adaptation are thought to be primary mechanisms. Freshwater habitats are highly susceptible to environmental change and exhibit marked ecological gradients. Standing waters appear to harbor more dispersive species than running waters, but there is little understanding of how this fundamental ecological difference has affected diversification. In contrast to the lack of evolutionary studies, the ecology and habitat preferences of aquatic insects have been intensively studied, in part because of their widespread use as bioindicators. The combination of phylogenetics with the extensive ecological data provides a promising avenue for future research, making aquatic insects highly suitable models for the study of ecological diversification.

  1. Trends in lead concentrations in major US rivers and their relation to historical changes in gasoline-lead consumption, by Richard B. Alexander and Richard A. Smith

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

    Flegal, A.R.; Coale, K.H.

    1989-12-01

    The sequential development of trace metal clean techniques has resulted in a systematic decrease in reported lead concentrations in the ocean. Similar decreases have been observed in reports of lead concentrations in fresh water. This was illustrated by the changes in reported baseline concentrations of lead in Lake Huron. However, even the latest (1980) of those concentrations (19 ng/L) appears to be erroneously high based on recent measurements of lead concentrations in the Great Lakes. Lead concentrations in surface waters in the center of Lake Ontario are < 2 ng/L or one order of magnitude lower than the reported baselinemore » concentration of Lake Huron in 1980. Corresponding concentrations of lead in surface waters of Lake Huron should be equal to or less than those in Lake Ontario. Anthropogenic lead fluxes to Lake Huron (621 metric tons per year) and Lake Ontario (592 metric tons per year) are comparable, while the assimilative capacity of Lake Huron is two-fold greater than that of Lake Ontario. Moreover, the atmospheric flux of industrial lead aerosols to surface waters in Lake Huron is approximately one half of the flux in Lake Ontario. Therefore, if removal rates are similar in these two lakes, the authors expect the baseline concentration of lead in Lake Huron to be {le} 2 ng/L or one order of magnitude lower than the 1980 baseline concentration. Concentrations in remote fresh water systems in North America, where inputs of industrial lead aerosols are orders of magnitude lower should also be < 2 ng/L. The preceding measurements and projected concentrations of lead in fresh water systems in North America are of note in light of some recent reports on the decrease of lead in natural waters within the US. Those reports are questionable, in spite of other reports of decreasing lead concentrations in the Mississippi River and North Atlantic.« less

  2. Characterisation of hydrogeological connections in a lowland karst network using time series analysis of water levels in ephemeral groundwater-fed lakes (turloughs)

    NASA Astrophysics Data System (ADS)

    Gill, L. W.; Naughton, O.; Johnston, P. M.; Basu, B.; Ghosh, B.

    2013-08-01

    This research has used continuous water level measurements five groundwater-fed lakes (or turloughs) in a linked lowland karst network of south Galway in Ireland over a 3 year period in order to elucidate the hydrogeological controls and conduit configurations forming the flooded karstic hydraulic system beneath the ground. The main spring outflow from this network discharges below mean sea level making it difficult to determine the hydraulic nature of the network using traditional rainfall-spring flow cross analysis, as has been done in many other studies on karst systems. However, the localised groundwater-surface water interactions (the turloughs) in this flooded lowland karst system can yield information about the nature of the hydraulic connections beneath the ground. Various different analytical techniques have been applied to the fluctuating turlough water level time series data in order to determine the nature of the linkage between them as well as hydraulic pipe configurations at key points in order to improve the conceptual model of the overall karst network. Initially, simple cross correlations between the different turlough water levels were carried out applying different time lags. Frequency analysis of the signals was then carried out using Fast Fourier transform analysis and then both discrete and continuous wavelet analyses have been applied to the data sets to characterise these inherently non-stationary time-series of fluctuating water levels. The analysis has indicated which turloughs are on the main line conduit system and which are somewhat off-line, the relative size of the main conduit in the network including evidence of localised constrictions, as well as clearly showing the tidal influence on the water levels in the three lower turloughs at shallow depths ∼8 km from the main spring outfall at the sea. It has also indicated that the timing of high rainfall events coincident with maximum spring tide levels may promote more consistent, long duration flooding of the turloughs throughout the winter.

  3. Effect of pH on lead removal from water using tree fern as the sorbent.

    PubMed

    Ho, Yuh-Shan

    2005-07-01

    The sorption of lead from water onto an agricultural by-product, tree fern, was examined as a function of pH. The sorption processes were carried out using an agitated and baffled system. Pseudo-second-order kinetic analyses were performed to determine the rate constant of sorption, the equilibrium sorption capacity, and the initial sorption rate. Application of the pseudo-second-order kinetics model produced very high coefficients of determination. Results showed the efficiency of tree fern as a sorbent for lead. The optimum pH for lead removal was between 4 and 7, with pH 4.9 resulting in better lead removal. Ion exchange occurred in the initial reaction period. In addition, a relation between the change in the solution hydrogen ion concentration and equilibrium capacity was developed and is presented.

  4. Characterization and treatment of water used for human consumption from six sources located in the Cameron/Tuba City abandoned uranium mining area.

    PubMed

    Orescanin, Visnja; Kollar, Robert; Nad, Karlo; Mikelic, Ivanka Lovrencic; Kollar, Iris

    2011-01-01

    The purpose of this research was the characterization and improvement of the quality of water used for human consumption of unregulated/regulated water sources located in the Cameron/Tuba City abandoned uranium mining area (NE Arizona, western edge of the Navajo Nation). Samples were collected at six water sources which included regulated sources: Wind Mill (Tank 3T-538), Badger Springs and Paddock Well as well as unregulated sources: Willy Spring, Water Wall and Water Hole. Samples taken from Wind Mill, Water Wall and Water Hole were characterized with high turbidity and color as well as high level of manganese, iron and nickel and elevated value of molybdenum. High level of iron was also found in Badger Spring, Willy Spring, and Paddock Well. These three water sources were also characterized with elevated values of fluoride and vanadium. Significant amounts of zinc were found in Water Wall and Water Hole samples. Water Wall sample was also characterized with high level of Cr(VI). Compared to primary or secondary Navajo Nation Environmental Protection Agency (NNEPA) water quality standard the highest enrichment was found for turbidity (50.000 times), color (up to 1.796 times) and manganese (71 times), Cr(VI) (17.5 times), iron (7.4 times) and arsenic (5.2 times). Activities of (226)Ra and (238)U in water samples were still in agreement with the maximum contaminant levels. In order to comply with NNEPA water quality standard water samples were subjected to electrochemical treatment. This method was selected due to its high removal efficiency for heavy metals and uranium, lower settlement time, production of smaller volume of waste mud and higher stability of waste mud compared to physico-chemical treatment. Following the treatment, concentrations of heavy metals and activities of radionuclides in all samples were significantly lower compared to NNEPA or WHO regulated values. The maximum removal efficiencies for color, turbidity, arsenic, manganese, molybdenum and nickel were 100.0%. Maximum removal percentage of Cu, F(-), V, Zn, (137)Cs, (226)Ra, (232)Th, (238)U were as follows: 98.0%; 82.7%; 99.9%; 95.6%; 75.0%; 76.9%; 80.0% and 99.2%. From the results presented it could be concluded that electrochemical treatment is a suitable approach for the purification of drinking water with complex mixture of contaminants, especially those with high turbidity and color.

  5. Temperature-induced water stress in high-latitude forests in response to natural and anthropogenic warming.

    PubMed

    Trahan, Matthew W; Schubert, Brian A

    2016-02-01

    The Arctic is particularly sensitive to climate change, but the independent effects of increasing atmospheric CO2 concentration (pCO2 ) and temperature on high-latitude forests are poorly understood. Here, we present a new, annually resolved record of stable carbon isotope (δ(13) C) data determined from Larix cajanderi tree cores collected from far northeastern Siberia in order to investigate the physiological response of these trees to regional warming. The tree-ring record, which extends from 1912 through 1961 (50 years), targets early twentieth-century warming (ETCW), a natural warming event in the 1920s to 1940s that was limited to Northern hemisphere high latitudes. Our data show that net carbon isotope fractionation (Δ(13) C), decreased by 1.7‰ across the ETCW, which is consistent with increased water stress in response to climate warming and dryer soils. To investigate whether this signal is present across the northern boreal forest, we compiled published carbon isotope data from 14 high-latitude sites within Europe, Asia, and North America. The resulting dataset covered the entire twentieth century and spanned both natural ETCW and anthropogenic Late Twentieth-Century Warming (~0.7 °C per decade). After correcting for a ~1‰ increase in Δ(13) C in response to twentieth century pCO2 rise, a significant negative relationship (r = -0.53, P < 0.0001) between the average, annual Δ(13) C values and regional annual temperature anomalies is observed, suggesting a strong control of temperature on the Δ(13) C value of trees growing at high latitudes. We calculate a 17% increase in intrinsic water-use efficiency within these forests across the twentieth century, of which approximately half is attributed to a decrease in stomatal conductance in order to conserve water in response to drying conditions, with the other half being attributed to increasing pCO2 . We conclude that annual tree-ring records from northern high-latitude forests record the effects of climate warming and pCO2 rise across the twentieth century. © 2015 John Wiley & Sons Ltd.

  6. Terrain and subsurface influences on runoff generation in a steep, deep, highly weathered system

    NASA Astrophysics Data System (ADS)

    Mallard, J. M.; McGlynn, B. L.; Richter, D. D., Jr.

    2017-12-01

    Our understanding of runoff generation in regions characterized by deep, highly weathered soils is incomplete, despite the prevalence occupation of these landscapes worldwide. To address this, we instrumented a first-order watershed in the Piedmont of South Carolina, USA, a region that extends east of the Appalachians from Maryland to Alabama, and home to some of the most rapid population growth in the country. Although regionally the relief is modest, the landscape is often highly dissected and local slopes can be steep and highly varied. The typical soils of the region are kaolinite dominated ultisols, with hydrologic properties controlled by argillic Bt horizons, often with >50% clay-size fraction. The humid subtropical climate creates relatively consistent precipitation intra-annually and seasonally variable energy availability. Consequently, the mixed deciduous and coniferous tree cover creates a strong evapotranspiration-mediated hydrologic dynamic. While moist soils and extended stream networks are typical from late fall through spring, relatively dry soils and contracting stream networks emerge in the summer and early fall. Here, we seek to elucidate the relative influence of the vertical soil and spatial terrain structure of this region on watershed hillslope hydrology and subsequent runoff generation. We installed a network of nested, shallow groundwater wells and soil water content probes within an ephemeral to first-order watershed to continuously measure soil and groundwater dynamics across soil horizons and landscape position. We also recorded local precipitation and discharge from this watershed. Most landscape positions exhibited minimal water table response to precipitation throughout dry summer periods, with infrequently observed responses rarely coincident with streamflow generation. In contrast, during the wetter late fall through early spring period, streamflow was driven by the interaction between transient perched water tables and topographically mediated redistribution of shallow groundwater downslope. Our findings suggest that understanding streamflow generation in regions possessing both complex terrain and complex vertical soil structure requires synchronous characterization of terrain mediated water redistribution and subsurface soil hydrology.

  7. Responses of aquatic insects to Cu and Zn in stream microcosms: understanding differences between single species tests and field responses.

    PubMed

    Clements, William H; Cadmus, Pete; Brinkman, Stephen F

    2013-07-02

    Field surveys of metal-contaminated streams suggest that some aquatic insects, particularly mayflies (Ephemeroptera) and stoneflies (Plecoptera), are highly sensitive to metals. However, results of single species toxicity tests indicate these organisms are quite tolerant, with LC50 values often several orders of magnitude greater than those obtained using standard test organisms (e.g., cladocerans and fathead minnows). Reconciling these differences is a critical research need, particularly since water quality criteria for metals are based primarily on results of single species toxicity tests. In this research we provide evidence based on community-level microcosm experiments to support the hypothesis that some aquatic insects are highly sensitive to metals. We present results of three experiments that quantified effects of Cu and Zn, alone and in combination, on stream insect communities. EC50 values, defined as the metal concentration that reduced abundance of aquatic insects by 50%, were several orders of magnitude lower than previously published values obtained from single species tests. We hypothesize that the short duration of laboratory toxicity tests and the failure to evaluate effects of metals on sensitive early life stages are the primary factors responsible for unrealistically high LC50 values in the literature. We also observed that Cu alone was significantly more toxic to aquatic insects than the combination of Cu and Zn, despite the fact that exposure concentrations represented theoretically similar toxicity levels. Our results suggest that water quality criteria for Zn were protective of most aquatic insects, whereas Cu was highly toxic to some species at concentrations near water quality criteria. Because of the functional significance of aquatic insects in stream ecosystems and their well-established importance as indicators of water quality, reconciling differences between field and laboratory responses and understanding the mechanisms responsible for variation in sensitivity among metals and metal mixtures is of critical importance.

  8. Ferrocene functionalized nanoscale mixed-oxides as a potent phosphate adsorbent from the synthetic and real (Persian Gulf) waters.

    PubMed

    Arshadi, M; Zandi, H; Akbari, J; Shameli, A

    2015-07-15

    The application of covalently attached ferrocene groups to the aluminum-silicate nanoparticles (ASNPs) for phosphate (P) removal from the synthetic and real waters has been studied and the prepared nanomaterials were analyzed by XPS, EDS, BET, TEM, chemical analysis (CHN), FTIR, and ICP-AES. The immobilization of the ferrocene on the surface of the inorganic support (mixed oxides) can lead to reduce the drawback of the pristine ferrocene molecules which may have strong tendency to agglomerate into larger particles, resulting in the negative effect on both available active sites and catalyst performance. XPS of Fe ions evidenced that most of the active sites of the nano-adsorbent is in the form of Fe(III) ions at the surface. The heterogeneous Fe(III) ions were effective toward removal of phosphate. The contact time to obtain equilibrium for maximum adsorption of phosphate (100%) was found to be 120 min. The adsorption kinetics of P has been evaluated in terms of pseudo-first- and -second-order kinetics, and the Freundlich and Langmuir isotherm models have also been tested to the equilibrium adsorption results. The adsorption process was spontaneous and endothermic in nature and followed pseudo-second-order kinetic model. FTIR, EDS and XPS results confirmed the formation of Fe-O-P bond on the Si/Al@Fe surface after adsorption of P from aqueous media. The Si/Al@Fe displayed high reusability due to its high removal capacity after 10th adsorption-desorption runs. The proposed adsorbent could also be utilized to adsorb the P ions from the real sample (Persian Gulf water). The high removal capacity of P ions from the real water and the high levels of reusability confirmed the versatility of the heterogenized ferrocene groups on the ASNPs. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. High-pressure behaviour of serpentine and elasticity systematics of hydrous and nominally anhydrous phases

    NASA Astrophysics Data System (ADS)

    Fumagalli, P.; Mookherjee, M.; Stixrude, L. P.

    2006-12-01

    Serpentine, talc and brucite occur in oceanic crust as alteration products of ultramafic rocks. As mineral phases occurring in the subduction zone setting, both along the slab and within the mantle wedge, they are possible candidates for carrying and tranfer of water to the deep earth. This is manifested by serpentine mud volcanoes, high electrical conductivities, magnetic and seismic anomalies. At high pressure talc transforms to the 10 Å phase. Both the 10 Å phase and serpentine eventually transfer their water content to other dense hydrous magnesium silicates stable at depth greater than 200 km. Most of the mantle's water budget may be contained in nominally anhydrous phases in which hydrogen occurs as non-stoichiometric defects. In order to evaluate the potential for remote detection of mantle water via seismology, we have investigated the elasticity systematics of hydrous phases, supplementing literature data with a new ab initio theoretical study of serpentine. Serpentine shows unusual high-pressure behavior. We predict a symmetry preserving phase transformation involving a proton flip near 25 GPa, and elastic instability at somewhat higher pressures that may be related with experimentally observed amorphization. Results of compression for the low-pressure phase is well represented by a fourth order Birch-Murnaghan finite strain expression with Ko= 81 GPa, Ko'= 9.12 and KoKo"= -142, where K is the bulk modulus, prime indicates pressure derivatives, and O refers to zero pressure. The elastic constant tensor reveals large acoustic anisotropy (41 % in VP) and seismic wave velocities that are significantly higher than those inferred from experiments on serpentinites. We find that serpentine and many other hydrous and nominally anhydrous phases conform closely to generalized Birch's laws in VP, VS, and VB versus density space. Coherent patterns emerge only if hydroxyls are treated as single "atomic" units in the computation of mean atomic weight, suggesting important implications for the understanding of the influence of hydrogen on mineral elasticity.

  10. Hurricanes Ingrid and Manuel (2013) and their impact on the salinity of the Meteoric Water Mass, Quintana Roo, Mexico

    NASA Astrophysics Data System (ADS)

    Coutino, Aaron; Stastna, Marek; Kovacs, Shawn; Reinhardt, Eduard

    2017-08-01

    We report on measurements of the salinity and temperature in the Yax Chen cave system on the Yuacatan peninsula. This paper is submitted together with Kovacs et al. (2017). Kovacs et al. focuses on the salinity levels of the meteoric lens, while this paper uses the observed results to elucidate the hydrodynamics. The cave passages have water depths on the order of 10 m, with flow on the order of ten centimeters a second, and as such is a hydrodynamic, as opposed to a porous, system. The measurements reveal that episodes of significant mixing between the fresh meteoric lens and the underlying salty water are driven by meteorological events (e.g., Hurricane Rina in 2011, and the twin Hurricanes Ingrid and Manuel in 2013). We find evidence that after the hurricanes in 2013, the water column remains unstable for several months. Through wavelet analysis, we find that the marine Water Mass (WM) exhibits much less low period activity compared to the meteoric WM. We hypothesize that the open cenotes are locations of high mixing intensity, with turbulent fronts propagating away from the sites of direct mixing into the cave network. We perform laboratory experiments and numerical simulations to explore this phenomenon, and find that mixing preferentially occurs on the flanks of regions of strong, stable density stratification (i.e., on the periphery of pycnoclines), and leads to entrainment of fluid into the turbulent region. Using high resolution direct numerical simulation, we explore the detailed manner in which turbulent entrainment can drive flow toward the mixing region, and lead to mixing of passive tracers. Finally, we discuss the implications of these results for the mixing of passive tracers, such as suspended chemicals.

  11. An investigation of the Performance of a Conical Solar Water Heater in the Kingdom of Bahrain

    NASA Astrophysics Data System (ADS)

    Gaaliche, Nessreen; Ayhan, Teoman; Fathallah, Raouf

    2017-11-01

    Domestic water heater corresponds to 25% of the house energy consumption and can play an important role to reduce energy house expenses. Solar energy offers a preferred renewable energy resource because of its economic and environmental advantages. It is considered the best alternative to reduce domestic water heater energy consumption cost. Converting solar energy into heat can be considered among the simplest used systems. Solar thermal conversion is more efficient than solar electrical direct conversion method. Solar water heater systems are particularly easy to use and to repair. The integrated conical solar collector water heater (ICSCWH) is so far the easiest among water heating systems. The ICSCWH converts directly and efficiently the solar flux into heat. In order to expand the utilization of ICSCWH systems, many design modifications have been examined and analyzed. This study provides an experimental investigation and mathematical simulation of an ICSCWH system equipped with a glass cover resulting in the increase of the maximum absorption. Integrating the cone-shaped heat collector with an aluminum spiral pipe flow system may enhance the efficiency of the proposed system. In order to maximize the solar radiation of the system, the solar water heater has been designed in a conical shape, which removes the need to change its orientation toward the sun to receive the maximum sun radiation during the day. In this system, the heating of water has been obtained using the spiral pipe flow without the use of the solar cells and mirrors in order to reduce the total cost. The storage water tank of this system is coupled with a conical solar collector. Based on the above design, the solar water heater has been fabricated and tested. In addition, an analytical modeling approach aiming to predict the flow rate within the conical integrated collector storage solar water heater (ICSSWH) and its efficiency, was developed. Modeling through a numerical simulation approach based on energy equations was performed. Considering the entire water amount and the total area of the cone, the amount of water (facing the sun per unit absorbing area in the two symmetrical parts of the system) is found to increase, which is expected to reach a maximum water temperature at a high performance. Our experimental findings show that the daily performance is around 32% and the highest water temperature of about 45°C is obtained in the system at 4 pm, according to seasons and weather conditions. An efficient and simple mathematical simulation approach for the new conical solar water heater is described then validates using experimental data.

  12. Natural fluoride levels from public water supplies in Piauí State, Brazil.

    PubMed

    Silva, Josiene Saibrosa da; Moreno, Wallesk Gomes; Forte, Franklin Delano Soares; Sampaio, Fábio Correia

    2009-01-01

    The aim of this work was to determine the natural fluoride concentrations in public water supplies in Piauí State, Brazil, in order to identify cities in risk for high prevalence of dental fluorosis. For each city, two samples of drinking water were collected in the urban area: one from the main public water supply and another from a public or residential tap from the same source. Fluoride analyses were carried out in duplicate using a specific ion electrode and TISAB II. From a total of 222 cities in Piauí, 164 (73.8%) samples were analyzed. Urban population in these towns corresponds to 92.5% of the whole state with an estimated population of 1,654,563 inhabitants from the total urban population (1,788,590 inhabitants). A total of 151 cities showed low fluoride levels (<0.30 mg/L) and 13 were just below optimum fluoride concentration in the drinking water (0.31-0.59 mg/L). High natural fluoride concentration above 0.81 mg/L was not observed in any of the surveyed cities. As a conclusion, most of the cities in Piauí have low fluoride concentration in the drinking water. The risk for a high prevalence of dental fluorosis in these urban areas due to natural fluoride in the water supplies is very unlikely. Thus, surveys about the dental fluorosis prevalence in Piauí should be related with data about the consumption of fluoridated dentifrices and other fluoride sources.

  13. Solid Electrolyte Materials for use in Lithium-water Primary Batteries And the Synthesis and Characterization of Lanthanide Orthoferrite Magnetic Nanomaterials

    NASA Astrophysics Data System (ADS)

    Cook, Clifford Corlin

    This thesis was developed in two parts with the overall goals of this work being (1) synthesize and develop solid electrolyte materials for use in a lithium-water battery and (2) synthesize and characterize ternary magnetic nanomaterials. Lithium metal in combination with water is a highly attractive power source due to its high specific energy. Because of the vigorous nature of the reaction between lithium and water, many obstacles must be overcome in order to harness the energy that this system is capable of producing. Parasitic reactions must be controlled so as not to passivate the lithium or consume it totally. In addition, production of hydrogen gas that accompanies both the electrochemical and parasitic reactions can present a serious challenge. As a result it is difficult to maintain high voltage and control the current density in these systems. In order to overcome these obstacles we have developed composite membranes of various lithium-ion conducting solid electrolytes and polymers. Lithium-ion conducting solid electrolytes are known to achieve ionic conductance as high as 10-3 S/cm2. Utilizing these materials in conjunction with polymers, we have created hydrophobic membranes that allow us to limit the parasitic reactions and maintain low cell impedance. Lanthanide orthoferrite materials are technologically important classes of magnetic materials. They have found application in magneto-optical devices as well as in magnetic recording devices. We have explored the syntheses and magnetic properties of nanocrystalline materials. The synthesis of the nanomaterials was done by co-reduction of lanthanide, Ln3+, and iron, Fe 3+, cations with alkalide solution producing the Ln-Fe alloy of the desired stoichiometry. Removal of the byproducts and oxidization of the alloy was accomplished by washing the product with aerated water. Presented herein, several nanoscale lanthanide orthoferrite materials (LnFeO3, Ln = Gd, Tb, Er, Tm, Sm, Dy, Ho, and La) have been prepared. The products have been characterized by X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), and magnetic properties characterized by use of a Superconducting Quantum Interference Device (SQUID).

  14. Solitary wave solutions and their interactions for fully nonlinear water waves with surface tension in the generalized Serre equations

    NASA Astrophysics Data System (ADS)

    Dutykh, Denys; Hoefer, Mark; Mitsotakis, Dimitrios

    2018-04-01

    Some effects of surface tension on fully nonlinear, long, surface water waves are studied by numerical means. The differences between various solitary waves and their interactions in subcritical and supercritical surface tension regimes are presented. Analytical expressions for new peaked traveling wave solutions are presented in the dispersionless case of critical surface tension. Numerical experiments are performed using a high-accurate finite element method based on smooth cubic splines and the four-stage, classical, explicit Runge-Kutta method of order 4.

  15. New methods for modeling stream temperature using high resolution LiDAR, solar radiation analysis and flow accumulated values to predict stream temperature

    EPA Science Inventory

    In-stream temperature directly effects a variety of biotic organisms, communities and processes. Changes in stream temperature can render formally suitable habitat unsuitable for aquatic organisms, particularly native cold water species that are not able to adjust. In order to...

  16. Trends in Nanosecond Melanosome Microcavitation Up to 1540 Nanometers

    DTIC Science & Technology

    2015-09-01

    these absorption coeffi- cients are probably due to the high water content and low mela - nin concentration in the RPE layer, as a simple first-order...comparison of radiant exposure thresholds of bovine mela - nosomes as a function of wavelength, on a log scale, from 532 to 1540 nm, at ambient

  17. 76 FR 39298 - Drawbridge Operation Regulation; Christina River, Wilmington, DE

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-06

    ... Operation Regulation; Christina River, Wilmington, DE AGENCY: Coast Guard, DHS. ACTION: Notice of temporary... River, at mile 2.8, in Wilmington, DE. The deviation restricts the operation of the draw span in order... Wilmington, DE has a vertical clearance in the closed position to vessels of 13 feet above mean high water...

  18. Re-growth of fecal indicator bacteria and Escherichia coli 0157:H7 B6914 in cow fecal extract

    EPA Science Inventory

    The health risks that pathogens pose to water and food resources are highly dependent on their fate and transport in agricultural settings. In order to assess these risks, an understanding of the factors that influence pathogen fate in agricultural settings is needed and is criti...

  19. 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.

  20. Microfabrication of polymeric surfaces with extreme wettability using hot embossing

    NASA Astrophysics Data System (ADS)

    Falah Toosi, Salma; Moradi, Sona; Ebrahimi, Marzieh; Hatzikiriakos, Savvas G.

    2016-08-01

    Hot embossing was utilized to imprint topographical metallic patterns on the surfaces of thermoplastic polymers in order to create superhydrophobic and superoleophobic polymeric surfaces. The stainless steel (SS) micro/nano structured templates were fabricated using femtosecond laser ablation. The SS laser ablated templates were employed to imprint micron/submicron periodic structures onto the surface of high density polyethylene (HDPE), polylactic acid (PLA), and medical PVC at temperatures slightly above their melting points and pressures in the range of 3-12 MPa. Results have shown that the water contact angle (CA) of imprinted polymers increased to above 160° in the case of PLA and HDPE, while their water contact angle hysteresis (CAH) were significantly below 10°. In the case of medical-PVC, imprinting produced morphologies with high CA and high CAH (petal effect) due to the adhesion forces developed at the interface between the hydrophilic plasticizer of medical-PVC (TOTM) and water droplets. It is also noted that the re-entrant superoleophobic patterns created on HDPE through imprinting closely resemble the patterns found on the surface of filefish skin that is densely angled microfiber arrays. This bioinspired surface is highly capable of repelling both polar (water) and non-polar liquids of low surface tension and meets the superoleophobicity criteria.

  1. Flood risk analysis and adaptive strategy in context of uncertainties: a case study of Nhieu Loc Thi Nghe Basin, Ho Chi Minh City

    NASA Astrophysics Data System (ADS)

    Ho, Long-Phi; Chau, Nguyen-Xuan-Quang; Nguyen, Hong-Quan

    2013-04-01

    The Nhieu Loc - Thi Nghe basin is the most important administrative and business area of Ho Chi Minh City. Due to system complexity of the basin such as the increasing trend of rainfall intensity, (tidal) water level and land subsidence, the simulation of hydrological, hydraulic variables for flooding prediction seems rather not adequate in practical projects. The basin is still highly vulnerable despite of multi-million USD investment for urban drainage improvement projects since the last decade. In this paper, an integrated system analysis in both spatial and temporal aspects based on statistical, GIS and modelling approaches has been conducted in order to: (1) Analyse risks before and after projects, (2) Foresee water-related risk under uncertainties of unfavourable driving factors and (3) Develop a sustainable flood risk management strategy for the basin. The results show that given the framework of risk analysis and adaptive strategy, certain urban developing plans in the basin must be carefully revised and/or checked in order to reduce the highly unexpected loss in the future

  2. External nutrient loading from land, sea and atmosphere to all 656 Swedish coastal water bodies.

    PubMed

    Bryhn, Andreas C; Dimberg, Peter H; Bergström, Lena; Fredriksson, Ronny E; Mattila, Johanna; Bergström, Ulf

    2017-01-30

    Identifying the main sources of nutrient loading is a key factor for efficient mitigation of eutrophication. This study has investigated the pathways of external nutrient loading to 656 coastal water bodies along the entire Swedish coastline. The studied water bodies have been delineated to meet requirements in the European Union's Water Framework Directive, and recent status assessments have shown that 57% of them fail to attain good or high ecological status with respect to nutrients. The analysis in the study was performed on data from mass-balance based nutrient budgets computed using the modelling framework Vattenwebb. The external nutrient contribution from the sea to the water bodies was highly variable, ranging from about 1% to nearly 100%, but the median contribution was >99% of the total external loading regarding both nitrogen and phosphorus. External loading from the atmosphere and local catchment area played a minor role in general. However, 45 coastal water bodies received >25% of the external nitrogen and phosphorus from their catchments. Loading from land typically peaked in April following ice-break and snow melting and was comparatively low during summer. The results indicate that for many eutrophicated Swedish coastal water bodies, nutrient abatement is likely to be optimally effective when potential measures in all of the catchment area of the concerned sea basin are considered. Local-scale mitigation in single water bodies will likely be locally effective only in the small proportion of areas where water and thereby also nutrient input from the catchment is high compared to the influx from the sea. Future studies should include nutrient reduction scenarios in order to refine these conclusions and to identify relevant spatial scales for coastal eutrophication mitigation measures from a water body perspective. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Using heat to characterize streambed water flux variability in four stream reaches

    USGS Publications Warehouse

    Essaid, H.I.; Zamora, C.M.; McCarthy, K.A.; Vogel, J.R.; Wilson, J.T.

    2008-01-01

    Estimates of streambed water flux are needed for the interpretation of streambed chemistry and reactions. Continuous temperature and head monitoring in stream reaches within four agricultural watersheds (Leary Weber Ditch, IN; Maple Creek, NE; DR2 Drain, WA; and Merced River, CA) allowed heat to be used as a tracer to study the temporal and spatial variability of fluxes through the streambed. Synoptic methods (seepage meter and differential discharge measurements) were compared with estimates obtained by using heat as a tracer. Water flux was estimated by modeling one-dimensional vertical flow of water and heat using the model VS2DH. Flux was influenced by physical heterogeneity of the stream channel and temporal variability in stream and ground-water levels. During most of the study period (April-December 2004), flux was upward through the streambeds. At the IN, NE, and CA sites, high-stage events resulted in rapid reversal of flow direction inducing short-term surface-water flow into the streambed. During late summer at the IN site, regional ground-water levels dropped, leading to surface-water loss to ground water that resulted in drying of the ditch. Synoptic measurements of flux generally supported the model flux estimates. Water flow through the streambed was roughly an order of magnitude larger in the humid basins (IN and NE) than in the arid basins (WA and CA). Downward flux, in response to sudden high streamflows, and seasonal variability in flux was most pronounced in the humid basins and in high conductivity zones in the streambed. Copyright ?? 2008 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

  4. Small effect of water on upper-mantle rheology based on silicon self-diffusion coefficients.

    PubMed

    Fei, Hongzhan; Wiedenbeck, Michael; Yamazaki, Daisuke; Katsura, Tomoo

    2013-06-13

    Water has been thought to affect the dynamical processes in the Earth's interior to a great extent. In particular, experimental deformation results suggest that even only a few tens of parts per million of water by weight enhances the creep rates in olivine by orders of magnitude. However, those deformation studies have limitations, such as considering only a limited range of water concentrations and very high stresses, which might affect the results. Rock deformation can also be understood as an effect of silicon self-diffusion, because the creep rates of minerals at temperatures as high as those in the Earth's interior are limited by self-diffusion of the slowest species. Here we experimentally determine the silicon self-diffusion coefficient DSi in forsterite at 8 GPa and 1,600 K to 1,800 K as a function of water content CH2O from less than 1 to about 800 parts per million of water by weight, yielding the relationship, DSi ≈ (CH2O)(1/3). This exponent is strikingly lower than that obtained by deformation experiments (1.2; ref. 7). The high nominal creep rates in the deformation studies under wet conditions may be caused by excess grain boundary water. We conclude that the effect of water on upper-mantle rheology is very small. Hence, the smooth motion of the Earth's tectonic plates cannot be caused by mineral hydration in the asthenosphere. Also, water cannot cause the viscosity minimum zone in the upper mantle. And finally, the dominant mechanism responsible for hotspot immobility cannot be water content differences between their source and surrounding regions.

  5. In-depth analysis and discussions of water absorption-typed high power laser calorimeter

    NASA Astrophysics Data System (ADS)

    Wei, Ji Feng

    2017-02-01

    In high-power and high-energy laser measurement, the absorber materials can be easily destroyed under long-term direct laser irradiation. In order to improve the calorimeter's measuring capacity, a measuring system directly using water flow as the absorber medium was built. The system's basic principles and the designing parameters of major parts were elaborated. The system's measuring capacity, the laser working modes, and the effects of major parameters were analyzed deeply. Moreover, the factors that may affect the accuracy of measurement were analyzed and discussed. The specific control measures and methods were elaborated. The self-calibration and normal calibration experiments show that this calorimeter has very high accuracy. In electrical calibration, the average correction coefficient is only 1.015, with standard deviation of only 0.5%. In calibration experiments, the standard deviation relative to a middle-power standard calorimeter is only 1.9%.

  6. One-pot synthesis of transition metal ion-chelating ordered mesoporous carbon/carbon nanotube composites for active and durable fuel cell catalysts

    NASA Astrophysics Data System (ADS)

    Dombrovskis, Johanna K.; Palmqvist, Anders E. C.

    2017-07-01

    Development of non-precious metal catalysts for the oxygen reduction reaction (ORR) in proton exchange membrane (PEM) fuel cells with high activity and durability and with optimal water management properties is of outmost technological importance and highly challenging. Here we study the possibilities offered through judicious selection of small molecular precursors used for the formation of ordered mesoporous carbon-based non-precious metal ORR catalysts. By combining two complementary precursors, we present a one-pot synthesis that leads to a composite material consisting of transition metal ion-chelating ordered mesoporous carbon and multi-walled carbon nanotubes (TM-OMC/CNT). The resulting composite materials show high specific surface areas and a carbon structure that exhibits graphitic signatures. The synthesis procedure allows for tuning of the carbon structure, the surface area, the pore volume and the ratio of the two components of the composite. The TM-OMC/CNT composites were processed into membrane electrode assemblies and evaluated in single cell fuel cell measurements where they showed a combination of good ORR activity and very high durability.

  7. Multivariate classification of small order watersheds in the Quabbin Reservoir Basin, Massachusetts

    USGS Publications Warehouse

    Lent, R.M.; Waldron, M.C.; Rader, J.C.

    1998-01-01

    A multivariate approach was used to analyze hydrologic, geologic, geographic, and water-chemistry data from small order watersheds in the Quabbin Reservoir Basin in central Massachusetts. Eighty three small order watersheds were delineated and landscape attributes defining hydrologic, geologic, and geographic features of the watersheds were compiled from geographic information system data layers. Principal components analysis was used to evaluate 11 chemical constituents collected bi-weekly for 1 year at 15 surface-water stations in order to subdivide the basin into subbasins comprised of watersheds with similar water quality characteristics. Three principal components accounted for about 90 percent of the variance in water chemistry data. The principal components were defined as a biogeochemical variable related to wetland density, an acid-neutralization variable, and a road-salt variable related to density of primary roads. Three subbasins were identified. Analysis of variance and multiple comparisons of means were used to identify significant differences in stream water chemistry and landscape attributes among subbasins. All stream water constituents were significantly different among subbasins. Multiple regression techniques were used to relate stream water chemistry to landscape attributes. Important differences in landscape attributes were related to wetlands, slope, and soil type.A multivariate approach was used to analyze hydrologic, geologic, geographic, and water-chemistry data from small order watersheds in the Quabbin Reservoir Basin in central Massachusetts. Eighty three small order watersheds were delineated and landscape attributes defining hydrologic, geologic, and geographic features of the watersheds were compiled from geographic information system data layers. Principal components analysis was used to evaluate 11 chemical constituents collected bi-weekly for 1 year at 15 surface-water stations in order to subdivide the basin into subbasins comprised of watersheds with similar water quality characteristics. Three principal components accounted for about 90 percent of the variance in water chemistry data. The principal components were defined as a biogeochemical variable related to wetland density, an acid-neutralization variable, and a road-salt variable related to density of primary roads. Three subbasins were identified. Analysis of variance and multiple comparisons of means were used to identify significant differences in stream water chemistry and landscape attributes among subbasins. All stream water constituents were significantly different among subbasins. Multiple regression techniques were used to relate stream water chemistry to landscape attributes. Important differences in landscape attributes were related to wetlands, slope, and soil type.

  8. Neonicotinoid contamination of global surface waters and associated risk to aquatic invertebrates: a review.

    PubMed

    Morrissey, Christy A; Mineau, Pierre; Devries, James H; Sanchez-Bayo, Francisco; Liess, Matthias; Cavallaro, Michael C; Liber, Karsten

    2015-01-01

    Neonicotinoids, broad-spectrum systemic insecticides, are the fastest growing class of insecticides worldwide and are now registered for use on hundreds of field crops in over 120 different countries. The environmental profile of this class of pesticides indicate that they are persistent, have high leaching and runoff potential, and are highly toxic to a wide range of invertebrates. Therefore, neonicotinoids represent a significant risk to surface waters and the diverse aquatic and terrestrial fauna that these ecosystems support. This review synthesizes the current state of knowledge on the reported concentrations of neonicotinoids in surface waters from 29 studies in 9 countries world-wide in tandem with published data on their acute and chronic toxicity to 49 species of aquatic insects and crustaceans spanning 12 invertebrate orders. Strong evidence exists that water-borne neonicotinoid exposures are frequent, long-term and at levels (geometric means=0.13μg/L (averages) and 0.63μg/L (maxima)) which commonly exceed several existing water quality guidelines. Imidacloprid is by far the most widely studied neonicotinoid (66% of the 214 toxicity tests reviewed) with differences in sensitivity among aquatic invertebrate species ranging several orders of magnitude; other neonicotinoids display analogous modes of action and similar toxicities, although comparative data are limited. Of the species evaluated, insects belonging to the orders Ephemeroptera, Trichoptera and Diptera appear to be the most sensitive, while those of Crustacea (although not universally so) are less sensitive. In particular, the standard test species Daphnia magna appears to be very tolerant, with 24-96hour LC50 values exceeding 100,000μg/L (geometric mean>44,000μg/L), which is at least 2-3 orders of magnitude higher than the geometric mean of all other invertebrate species tested. Overall, neonicotinoids can exert adverse effects on survival, growth, emergence, mobility, and behavior of many sensitive aquatic invertebrate taxa at concentrations at or below 1μg/L under acute exposure and 0.1μg/L for chronic exposure. Using probabilistic approaches (species sensitivity distributions), we recommend here that ecological thresholds for neonicotinoid water concentrations need to be below 0.2μg/L (short-term acute) or 0.035μg/L (long-term chronic) to avoid lasting effects on aquatic invertebrate communities. The application of safety factors may still be warranted considering potential issues of slow recovery, additive or synergistic effects and multiple stressors that can occur in the field. Our analysis revealed that 81% (22/27) and 74% (14/19) of global surface water studies reporting maximum and average individual neonicotinoid concentrations respectively, exceeded these thresholds of 0.2 and 0.035μg/L. Therefore, it appears that environmentally relevant concentrations of neonicotinoids in surface waters worldwide are well within the range where both short- and long-term impacts on aquatic invertebrate species are possible over broad spatial scales. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Determining the Economic Feasibility of Using Produced Water for Agriculture in Colorado Through Life Cycle Cost Analyses

    NASA Astrophysics Data System (ADS)

    Dolan, F.; Blaine, A. C.; Hogue, T. S.

    2016-12-01

    To combat the need for new sources of water in Colorado, the current research looks to produced water as a potential source. Produced water, the water produced alongside oil and gas in a well, is currently viewed as a high-volume waste product; however, this water can potentially be used to irrigate food or non-food crops after treatment. Kern County in California has been using produced water for this purpose for over 20 years and a town in Colorado has followed suit. Our research seeks to determine how Wellington, CO overcame economic, legal, social, and technological barriers in order to put produced water to beneficial use. Life cycle cost analyses of produced water in three counties in Colorado are conducted to determine the economic feasibility of using produced water for irrigation on a broad scale. The current study is chosen based on the quality and quantity of the region's produced water as well as the need for new sources of water within the county. The results of this research will help in the transition between viewing produced water as a waste product and using it as a tool to help secure Colorado's water future.

  10. Exceptionally fast water desalination at complete salt rejection by pristine graphyne monolayers.

    PubMed

    Xue, Minmin; Qiu, Hu; Guo, Wanlin

    2013-12-20

    Desalination that produces clean freshwater from seawater holds the promise of solving the global water shortage for drinking, agriculture and industry. However, conventional desalination technologies such as reverse osmosis and thermal distillation involve large amounts of energy consumption, and the semipermeable membranes widely used in reverse osmosis face the challenge to provide a high throughput at high salt rejection. Here we find by comprehensive molecular dynamics simulations and first principles modeling that pristine graphyne, one of the graphene-like one-atom-thick carbon allotropes, can achieve 100% rejection of nearly all ions in seawater including Na(+), Cl(-), Mg(2+), K(+) and Ca(2+), at an exceptionally high water permeability about two orders of magnitude higher than those for commercial state-of-the-art reverse osmosis membranes at a salt rejection of ~98.5%. This complete ion rejection by graphyne, independent of the salt concentration and the operating pressure, is revealed to be originated from the significantly higher energy barriers for ions than for water. This intrinsic specialty of graphyne should provide a new possibility for the efforts to alleviate the global shortage of freshwater and other environmental problems.

  11. Fabrication of water-dispersible single-walled carbon nanotube powder using N-methylmorpholine N-oxide

    NASA Astrophysics Data System (ADS)

    Choi, Hyejun; Woo, Jong Seok; Tark Han, Joong; Park, Soo-Young

    2017-11-01

    Dispersion of nanocarbon materials in liquid media, via solution processing such as spraying, printing, spinning, etc. is one of the prerequisites for practical applications. Here we report that water-dispersible single-walled carbon nanotubes (SWCNTs) were prepared through successive treatments with chlorosulfuric acid (CSA)/H2O2 and N-methylmorpholine N-oxide (NMO) monohydrate. The powder of the CSA/H2O2- and NMO-treated SWCNTs (N-SWCNTs) could be readily redispersed in water in concentrations as high as 1 g l-1 without requiring a dispersant. The mechanism responsible for the high dispersity of the N-SWCNT powder in polar solvents, including water, was elucidated based on the high polarity of the NMO molecule. In order to highlight the wide applicability of the N-SWCNTs, they were used successfully to prepare conducting thin films by spray-coating plastic substrates with an aqueous hybrid solution containing the N-SWCNTs and Ag nanowires (NWs). In addition, a flexible, large-area thin-film heater was prepared based on the N-SWCNT/AgNW hybrid film with a transmittance of 93% and sheet resistance of 30 Ω sq-1.

  12. Strong copper(II) species in estuarine and sea waters investigated by a method with high detection window.

    PubMed

    Alberti, Giancarla; Biesuz, Raffaela; D'Agostino, Girolamo; Scarponi, Giuseppe; Pesavento, Maria

    2007-02-15

    The distribution of copper(II) in species of different stability in some estuarine and sea water samples (Adriatic Sea) was investigated by a method based on the sorption of the metal ion on a strongly sorbing resin, Chelex 100, whose sorbing properties have been previously characterized. From them, it is possible to predict very high values of detection windows at the considered conditions, for example side reaction coefficient as high as 10(10) at pH 7.5. Strong copper(II) species in equilibrium with Chelex 100 were detected, at concentration 2-20nM, with a reaction coefficient approximately 10(10.6) at pH 7.45 in sea water, strictly depending on the acidity. They represent 50-70% of the total metal ion and are the strongest copper(II) complexes found in sea water. Weak complexes too were detected in all the samples, with reaction coefficient lower than ca. 10(9) at the same pH. The method applied, named resin titration (RT), was described in a previous investigation, and is here modified in order to be carried out on oceanographic boat during a cruise in the Adriatic Sea.

  13. Mesoporous ZrO2 fibers with enhanced surface area and the application as recyclable absorbent

    NASA Astrophysics Data System (ADS)

    Yu, Zhichao; Liu, Benxue; Zhou, Haifeng; Feng, Cong; Wang, Xinqiang; Yuan, Kangkang; Gan, Xinzhu; Zhu, Luyi; Zhang, Guanghui; Xu, Dong

    2017-03-01

    Highly crystalline mesoporous zirconia fibers with high surface area have been prepared by the use of electrospinning combined with precursors method. The obtained precursor fibers were treated in water steam and directly in air at different temperature respectively. Compared with the direct calcination in air, the water steam cannot only promote the crystallization of ZrO2 but also effectively remove off the organics and prevent the pore structure collapse. Moreover, through adding hydrochloric acid to modify the solution pH value, the obtained t-ZrO2 fibers treated in water steam at 300 °C have high surface area and large pore volume of 232.70 m2 g-1 and 0.36 cm3 g-1. The formation mechanism of the mesostucture was studied and the schematic was represented. Compared with the previous reports of mesoporous ZrO2 fibers, the as-synthesized materials exhibited the high crystallinity, large surface area and the long-range order mesostructure.The adsorption of Congo red indicates that the samples have a high adsorption capacity of 103.46 mg g-1 and long-periodic repeated availability.

  14. A Dynamic Eddy Viscosity Model for the Shallow Water Equations Solved by Spectral Element and Discontinuous Galerkin Methods

    NASA Astrophysics Data System (ADS)

    Marras, Simone; Suckale, Jenny; Giraldo, Francis X.; Constantinescu, Emil

    2016-04-01

    We present the solution of the viscous shallow water equations where viscosity is built as a residual-based subgrid scale model originally designed for large eddy simulation of compressible [1] and stratified flows [2]. The necessity of viscosity for a shallow water model not only finds motivation from mathematical analysis [3], but is supported by physical reasoning as can be seen by an analysis of the energetics of the solution. We simulated the flow of an idealized wave as it hits a set of obstacles. The kinetic energy spectrum of this flow shows that, although the inviscid Galerkin solutions -by spectral elements and discontinuous Galerkin [4]- preserve numerical stability in spite of the spurious oscillations in the proximity of the wave fronts, the slope of the energy cascade deviates from the theoretically expected values. We show that only a sufficiently small amount of dynamically adaptive viscosity removes the unwanted high-frequency modes while preserving the overall sharpness of the solution. In addition, it yields a physically plausible energy decay. This work is motivated by a larger interest in the application of a shallow water model to the solution of tsunami triggered coastal flows. In particular, coastal flows in regions around the world where coastal parks made of mitigation hills of different sizes and configurations are considered as a means to deviate the power of the incoming wave. References [1] M. Nazarov and J. Hoffman (2013) "Residual-based artificial viscosity for simulation of turbulent compressible flow using adaptive finite element methods" Int. J. Numer. Methods Fluids, 71:339-357 [2] S. Marras, M. Nazarov, F. X. Giraldo (2015) "Stabilized high-order Galerkin methods based on a parameter-free dynamic SGS model for LES" J. Comput. Phys. 301:77-101 [3] J. F. Gerbeau and B. Perthame (2001) "Derivation of the viscous Saint-Venant system for laminar shallow water; numerical validation" Discrete Contin. Dyn. Syst. Ser. B, 1:89?102 [4] F. X. Giraldo and M. Restelli (2010) "High-order semi-implicit time-integrators for a triangular discontinuous Galerkin oceanic shallow water model. Int. J. Numer. Methods Fluids, 63:1077-1102

  15. Evaluation on Cost Overrun Risks of Long-distance Water Diversion Project Based on SPA-IAHP Method

    NASA Astrophysics Data System (ADS)

    Yuanyue, Yang; Huimin, Li

    2018-02-01

    Large investment, long route, many change orders and etc. are main causes for costs overrun of long-distance water diversion project. This paper, based on existing research, builds a full-process cost overrun risk evaluation index system for water diversion project, apply SPA-IAHP method to set up cost overrun risk evaluation mode, calculate and rank weight of every risk evaluation indexes. Finally, the cost overrun risks are comprehensively evaluated by calculating linkage measure, and comprehensive risk level is acquired. SPA-IAHP method can accurately evaluate risks, and the reliability is high. By case calculation and verification, it can provide valid cost overrun decision making information to construction companies.

  16. [A Method Research on Environmental Damage Assessment of a Truck Rollover Pollution Incident].

    PubMed

    Cai, Feng; Zhao, Shi-ho; Chen, Gang-cai; Xian, Si-shu; Yang, Qing-ling; Zhou, Xian-jie; Yu, Hai

    2015-05-01

    With high occurrence of sudden water pollution incident, China faces an increasingly severe situation of water environment. In order to deter the acts of environmental pollution, ensure the damaged resources of environment can be restored and compensated, it is very critical to quantify the economic losses caused by the sudden water pollution incident. This paper took truck rollover pollution incidents in Chongqing for an example, established a set of evaluation method for quantifying the environmental damage, and then assessed the environmental damage by the method from four aspects, including the property damage, ecological environment and resources damages, the costs of administrative affairs in emergency disposal, and the costs of investigation and evaluation.

  17. Embedded optical fibers for PDV measurements in shock-loaded, light and heavy water

    NASA Astrophysics Data System (ADS)

    Mercier, Patrick; Benier, Jacky; Frugier, Pierre Antoine; Debruyne, Michel; Bolis, Cyril

    2012-03-01

    In order to study the shock-detonation transition, we propose to characterize the shock loading of a high explosive plane wave generator into a nitromethane cell. To eliminate the reactive behaviour, we replace the nitromethane by an inert liquid compound. Light water (H2O) has been first employed; eventually heavy water (D2O) has been chosen for its better infrared spectral properties. We present the PDV results of different embedded optical fibers which sense the medium with two different approaches: a non intrusive optical observation of phenomena coming in front of them (interface, shock wave, detonation wave) followed by their mechanical interaction with the fiber.

  18. Effects of the gaseous and liquid water content of the atmosphere on range delay and Doppler frequency

    NASA Technical Reports Server (NTRS)

    Flock, W. L.

    1981-01-01

    When high precision is required for range measurement on Earth space paths, it is necessary to correct as accurately as possible for excess range delays due to the dry air, water vapor, and liquid water content of the atmosphere. Calculations based on representative values of atmospheric parameters are useful for illustrating the order of magnitude of the expected delays. Range delay, time delay, and phase delay are simply and directly related. Doppler frequency variations or noise are proportional to the time rate of change of excess range delay. Tropospheric effects were examined as part of an overall consideration of the capability of precision two way ranging and Doppler systems.

  19. 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.

  20. Evaluation of less-lethal characteristics of a chemical delivery system for use by prison and corrections departments

    NASA Astrophysics Data System (ADS)

    Cuadros, Jaime H.

    1998-12-01

    The use of high pressure water streams to disperse crowds, in general, and to subdue unruly individuals in a prison environment has been shown to be an effective way to reduce the severity of the confrontations among the inmates and guards. The less lethal chemical delivery system (Hydro-Force) disperses chemicals, such as oleoresin capsicum or 'pepper spray' (OC), in the high pressure water stream. The high pressure water stream is aimed to impact the target individuals. A close miss overhead is still very effective as the water mixture can 'ran' on them and soak the target individuals. The effect of the OC is multiplied by the whole body exposure with excellent results in stopping any undesirable behavior of the target individuals, without bodily contact or struggle with the guards. The possibility of producing blunt trauma damage by the impact of the water stream, at close range, was a concern to be investigated. The water stream can be considered as a special fluid kinetic energy projectile. At impact, the kinetic energy of the mass and velocity of the stream of water is dissipated and its momentum is transferred to the target. The purpose of this cursory study is to evaluate whether the physiological effects of this impact is below the threshold of damage or lethality. Comparisons are made, where the two crucial elements, the force coupled to the target and the duration of its application, in order to establish the probably level of blunt trauma associated with the use of the water jet.

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