Magnetic water-in-water droplet microfluidics

NASA Astrophysics Data System (ADS)

Navi, Maryam; Abbasi, Niki; Tsai, Scott

2017-11-01

Aqueous two-phase systems (ATPS) have shown to be ideal candidates for replacing the conventional water-oil systems used in droplet microfluidics. We use an ATPS of Polyethylene Glycol (PEG) and Dextran (DEX) for microfluidic generation of magnetic water-in-water droplets. As ferrofluid partitions to DEX phase, there is no significant diffusion of ferrofluid at the interface of the droplets, rendering generation of magnetic DEX droplets in a non-magnetic continuous phase of PEG possible. In this system, both phases are water-based and highly biocompatible. We microfluidically generate magnetic DEX droplets at a flow-focusing junction in a jetting regime. We sort the droplets based on their size by placing a permanent magnet downstream of the droplet generation region, and show that the deflection of droplets is in good agreement with a mathematical model. We also show that the magnetic DEX droplets can be stabilized by lysozyme and be used for separation of single cell containing water-in-water droplets. This system of magnetic water-in-water droplet manipulation may find biomedical applications such as single-cell studies and drug delivery.

New porous monolithic membranes based on supported ionic liquid-like phases for oil/water separation and homogenous catalyst immobilisation.

PubMed

Porcar, Raúl; Nuevo, Daniel; García-Verdugo, Eduardo; Lozano, Pedro; Sanchez-Marcano, José; Burguete, M Isabel; Luis, Santiago V

2018-03-07

Porous monolithic advanced functional materials based on supported ionic liquid-like phase (SILLP) systems were used for the preparation of oleophilic and hydrophobic cylindrical membranes and successfully tested as eco-friendly and safe systems for oil/water separation and for the continuous integration of catalytic and separation processes in an aqueous-organic biphasic reaction system.

Biological treatment of soils contaminated with hydrophobic organics using slurry- and solid-phase techniques

NASA Astrophysics Data System (ADS)

Cassidy, Daniel H.; Irvine, Robert L.

1995-10-01

Both slurry-phase and solid-phase bioremediation are effective ex situ soil decontamination methods. Slurrying is energy intensive relative to solid-phase treatment, but provides homogenization and uniform nutrient distribution. Limited contaminant bioavailability at concentrations above the required cleanup level reduces biodegradation rates and renders solid phase bioremediation more cost effective than complete treatment in a bio-slurry reactor. Slurrying followed by solid-phase bioremediation combines the advantages and minimizes the weaknesses of each treatment method when used alone. A biological treatment system consisting of slurrying followed by aeration in solid phase bioreactors was developed and tested in the laboratory using a silty clay loam contaminated with diesel fuel. The first set of experiments was designed to determine the impact of the water content and mixing time during slurrying on the rate an extent of contaminant removal in continuously aerated solid phase bioreactors. The second set of experiments compared the volatile and total diesel fuel removal in solid phase bioreactors using periodic and continuous aeration strategies. Results showed that slurrying for 1.5 hours at a water content less than saturation markedly increased the rate and extent of contaminant biodegradation in the solid phase bioreactors compared with soil having no slurry pretreatment. Slurrying the soil at or above its saturation moisture content resulted in lengthy dewatering times which prohibited aeration, thereby delaying the onset of biological treatment in the solid phase bioreactors. Results also showed that properly operated periodic aeration can provide less volatile contaminant removal and a grater fraction of biological contaminant removal than continuous aeration.

A bicontinuous tetrahedral structure in a liquid-crystalline lipid

NASA Astrophysics Data System (ADS)

Longley, William; McIntosh, Thomas J.

1983-06-01

The structure of most lipid-water phases can be visualized as an ordered distribution of two liquid media, water and hydrocarbons, separated by a continuous surface covered by the polar groups of the lipid molecules1. In the cubic phases in particular, rod-like elements are linked into three-dimensional networks1,2. Two of these phases (space groups Ia3d and Pn3m) contain two such three-dimensional networks mutually inter-woven and unconnected. Under the constraints of energy minimization3, the interface between the components in certain of these `porous fluids' may well resemble one of the periodic minimal surface structures of the type described mathematically by Schwarz4,5. A structure of this sort has been proposed for the viscous isotropic (cubic) form of glycerol monooleate (GMO) by Larsson et al.6 who suggested that the X-ray diagrams of Lindblom et al.7 indicated a body-centred crystal structure in which lipid bilayers might be arranged as in Schwarz's octahedral surface4. We have now found that at high water contents, a primitive cubic lattice better fits the X-ray evidence with the material in the crystal arranged in a tetrahedral way. The lipid appears to form a single bilayer, continuous in three dimensions, separating two continuous interlinked networks of water. Each of the water networks has the symmetry of the diamond crystal structure and the bilayer lies in the space between them following a surface resembling Schwarz's tetrahedral surface4.

Activities of the National Water-Quality Assessment Program in the upper Snake River Basin, Idaho and western Wyoming, 1991-2001

USGS Publications Warehouse

Low, Walton H.

1997-01-01

In 1991, the U.S. Geological Survey (USGS) began a full-scale National Water-Quality Assessment (NAWQA) Program. The long-term goals of the NAWQA Program are to describe the status and trends in the water quality of a large part of the Nation's rivers and aquifers and to improve understanding of the primary natural and human factors that affect water-quality conditions. In meeting these goals, the program will produce water-quality, ecological, and geographic information that will be useful to policy makers and managers at the national, State, and local levels. A major component of the program is study-unit investigations, upon which national-level assessment activities are based. The program's 60 study-unit investigations are associated with principal river basins and aquifer systems throughout the Nation. Study units encompass areas from 1,200 to more than 65,000 mi2 (square miles) and incorporate about 60 to 70 percent of the Nation's water use and population served by public water supply. In 1991, the upper Snake River Basin was among the first 20 NAWQA study units selected for implementation. From 1991 to 1995, a high-intensity data-collection phase of the upper Snake River Basin study unit (fig. 1) was implemented and completed. Components of this phase are described in a report by Gilliom and others (1995). In 1997, a low-intensity phase of data collection began, and work continued on data analysis, report writing, and data documentation and archiving activities that began in 1996. Principal data-collection activities during the low-intensity phase will include monitoring of surface-water and ground-water quality, assessment of aquatic biological conditions, and continued compilation of environmental setting information.

Formulation, Implementation and Validation of a Two-Fluid model in a Fuel Cell CFD Code

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

Jain, Kunal; Cole, J. Vernon; Kumar, Sanjiv

2008-12-01

Water management is one of the main challenges in PEM Fuel Cells. While water is essential for membrane electrical conductivity, excess liquid water leads to flooding of catalyst layers. Despite the fact that accurate prediction of two-phase transport is key for optimal water management, understanding of the two-phase transport in fuel cells is relatively poor. Wang et. al. have studied the two-phase transport in the channel and diffusion layer separately using a multiphase mixture model. The model fails to accurately predict saturation values for high humidity inlet streams. Nguyen et. al. developed a two-dimensional, two-phase, isothermal, isobaric, steady state modelmore » of the catalyst and gas diffusion layers. The model neglects any liquid in the channel. Djilali et. al. developed a three-dimensional two-phase multicomponent model. The model is an improvement over previous models, but neglects drag between the liquid and the gas phases in the channel. In this work, we present a comprehensive two-fluid model relevant to fuel cells. Models for two-phase transport through Channel, Gas Diffusion Layer (GDL) and Channel-GDL interface, are discussed. In the channel, the gas and liquid pressures are assumed to be same. The surface tension effects in the channel are incorporated using the continuum surface force (CSF) model. The force at the surface is expressed as a volumetric body force and added as a source to the momentum equation. In the GDL, the gas and liquid are assumed to be at different pressures. The difference in the pressures (capillary pressure) is calculated using an empirical correlations. At the Channel-GDL interface, the wall adhesion affects need to be taken into account. SIMPLE-type methods recast the continuity equation into a pressure-correction equation, the solution of which then provides corrections for velocities and pressures. However, in the two-fluid model, the presence of two phasic continuity equations gives more freedom and more complications. A general approach would be to form a mixture continuity equation by linearly combining the phasic continuity equations using appropriate weighting factors. Analogous to mixture equation for pressure correction, a difference equation is used for the volume/phase fraction by taking the difference between the phasic continuity equations. The relative advantages of the above mentioned algorithmic variants for computing pressure correction and volume fractions are discussed and quantitatively assessed. Preliminary model validation is done for each component of the fuel cell. The two-phase transport in the channel is validated using empirical correlations. Transport in the GDL is validated against results obtained from LBM and VOF simulation techniques. The Channel-GDL interface transport will be validated against experiment and empirical correlation of droplet detachment at the interface.« less

Process for producing fuel grade ethanol by continuous fermentation, solvent extraction and alcohol separation

DOEpatents

Tedder, Daniel W.

1985-05-14

Alcohol substantially free of water is prepared by continuously fermenting a fermentable biomass feedstock in a fermentation unit, thereby forming an aqueous fermentation liquor containing alcohol and microorganisms. Continuously extracting a portion of alcohol from said fermentation liquor with an organic solvent system containing an extractant for said alcohol, thereby forming an alcohol-organic solvent extract phase and an aqueous raffinate. Said alcohol is separated from said alcohol-organic solvent phase. A raffinate comprising microorganisms and unextracted alcohol is returned to the fermentation unit.

Interdroplet attractive forces in AOT water-in-oil microemulsions formed in subcritical and supercritical solvents

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

Tingey, J.M.; Fulton, J.L.; Smith, R.D.

1990-03-08

The van der Waals attractive interactions between aqueous droplets in water-in-oil type microemulsions have been investigated for a range of continuous-phase solvents including the alkanes from methane to isooctane and the noble gases, krypton and xenon. Hamaker constants for water droplets with surfactant shells of the sodium bis(2-ethylhexyl) sulfosuccinate (AOT) in subcritical and supercritical solvents were calculated by using Lifshitz theory and the resulting interaction potential calculations qualitatively account for many features of the phase behavior of these systems.

Wrapping with a splash: High-speed encapsulation with ultrathin sheets

NASA Astrophysics Data System (ADS)

Kumar, Deepak; Paulsen, Joseph D.; Russell, Thomas P.; Menon, Narayanan

2018-02-01

Many complex fluids rely on surfactants to contain, protect, or isolate liquid drops in an immiscible continuous phase. Thin elastic sheets can wrap liquid drops in a spontaneous process driven by capillary forces. For encapsulation by sheets to be practically viable, a rapid, continuous, and scalable process is essential. We exploit the fast dynamics of droplet impact to achieve wrapping of oil droplets by ultrathin polymer films in a water phase. Despite the violence of splashing events, the process robustly yields wrappings that are optimally shaped to maximize the enclosed fluid volume and have near-perfect seams. We achieve wrappings of targeted three-dimensional (3D) shapes by tailoring the 2D boundary of the films and show the generality of the technique by producing both oil-in-water and water-in-oil wrappings.

Biodegradation of chloroethene compounds in groundwater at Operable Unit 1, Naval Undersea Warfare Center, Division Keyport, Washington, 1999-2010

USGS Publications Warehouse

Dinicola, R.S.; Huffman, R.L.

2012-01-01

Flux calculations based on 2010 data indicate that 95 percent of dissolved-phase chloroethenes in the upper aquifer beneath the southern landfill were degraded before discharging to surface water. Overall, biodegradation of chloroethenes in groundwater throughout OU 1 continued through 2010, and it prevented most of the mass of dissolved-phase chloroethenes in the upper aquifer beneath the landfill from discharging to surface water.

Influence of Sodium Chloride on the Formation and Dissociation Behavior of CO2 Gas Hydrates.

PubMed

Holzammer, Christine; Schicks, Judith M; Will, Stefan; Braeuer, Andreas S

2017-09-07

We present an experimental study on the formation and dissociation characteristics of carbon dioxide (CO 2 ) gas hydrates using Raman spectroscopy. The CO 2 hydrates were formed from sodium chloride/water solutions with salinities of 0-10 wt %, which were pressurized with liquid CO 2 in a stirred vessel at 6 MPa and a subcooling of 9.5 K. The formation of the CO 2 hydrate resulted in a hydrate gel where the solid hydrate can be considered as the continuous phase that includes small amounts of a dispersed liquid water-rich phase that has not been converted to hydrate. During the hydrate formation process we quantified the fraction of solid hydrate, x H , and the fraction of the dispersed liquid water-rich phase, x L , from the signature of the hydroxyl (OH)-stretching vibration of the hydrate gel. We found that the fraction of hydrate x H contained in the hydrate gel linearly depends on the salinity of the initial liquid water-rich phase. In addition, the ratio of CO 2 and water was analyzed in the liquid water-rich phase before hydrate formation, in the hydrate gel during growth and dissociation, and after its complete dissociation again in the liquid water-rich phase. We observed a supersaturation of CO 2 in the water-rich phase after complete dissociation of the hydrate gel and were able to show that the excess CO 2 exists as dispersed micro- or nanoscale liquid droplets in the liquid water-rich phase. These residual nano- and microdroplets could be a possible explanation for the so-called memory effect.

Management of the diffusion of 4-methylumbelliferone across phases in microdroplet-based systems for in vitro protein evolution.

PubMed

Wu, Nan; Courtois, Fabienne; Zhu, Yonggang; Oakeshott, John; Easton, Chris; Abell, Chris

2010-09-01

Fluorongenic reagents based on 4-methylumbelliferone (4-MU) have been widely used for the detection of phosphatase, sulfatase, esterase, lipase and glycosidase activities in conventionally formatted enzyme assay systems. However, the sensitivity of assays based on these substrates is also potentially very useful in the microdroplet formats now being developed for high throughput in vitro evolution experiments. In this article, we report the investigation of diffusion of 4-MU as a model dye from water-in-oil droplets and the internal aqueous phase of water-in-oil-in-water droplets in microfluidics. The effect of BSA in the aqueous phase on the diffusion of 4-MU is also discussed. Based on these results, we provided here proof-of-concept of the reaction of the enzyme OpdA with the substrate coumaphos in water-in-oil-in-water droplets. In this double-emulsion system, the reaction of OpdA and coumaphos was achieved by allowing coumaphos to diffuse from the continuous aqueous phase across the oil phase into the internal aqueous droplets.

Project NOAH: Regulating modern sea-level rise. Phase II: Jerusalem Underground

NASA Astrophysics Data System (ADS)

Newman, Walter S.; Fairbridge, Rhodes W.

This proposal builds a high-speed inter-urban express between Jerusalem and Tel Aviv, generates 1500 megawatts of hydroelectric energy, curtails littoral erosion, builds a port along the Israeli Mediterranean coast and demands peaceful cooperation on both sides of the Jordan River. Phase II represents a pilot project demonstrating the feasibility of continuing to regulate world sea-level by a new series of water regulation schemes. Phase I previously described all those projects already completed or underway which have inadvertently and/or unintentionally served the purpose of sea-level regulation. These forms of Phase I sea-level regulation include large and small reservoirs, irrigation projects, water infiltration schemes, farm ponds, and swimming and reflecting pools. All these water storage projects have already exercised a very appreciable brake on 20th century sea-level rise. Phase II outlines a high-visibility proposal which will serve to illustrate the viability of “Project NOAH”.

Water- and air-quality monitoring of the Sweetwater Reservoir Watershed, San Diego County, California-Phase One results, continued, 1999-2001

USGS Publications Warehouse

Mendez, Gregory O.; Foreman, William T.; Sidhu, Jagdeep S.; Majewski, Michael S.

2007-01-01

In 1998, the U.S. Geological Survey, in cooperation with the Sweetwater Authority, began a study to assess the overall health of the Sweetwater watershed with respect to chemical contamination. The study included regular sampling of air and water at Sweetwater Reservoir for chemical contaminants, including volatile organic compounds, polycyclic aromatic hydrocarbons, pesticides, and major and trace elements. Background water samples were collected at Loveland Reservoir for volatile organic compounds and pesticides. The purpose of this study was to monitor changes in contaminant composition and concentration in the air and water resulting from the construction and operation of State Route 125 near Sweetwater Reservoir. To accomplish this, the study was divided into two phases. Phase One sampling was designed to establish baseline conditions for target compounds in terms of detection frequency and concentration in air and water. Phase Two sampling is planned to continue at the established monitoring sites during and after construction of State Route 125 to assess the chemical impact this roadway alignment project may have on the water quality in the reservoir. In addition to the ongoing data collection, several special studies were initiated to assess the occurrence of specific chemicals of concern, such as low-use pesticides, trace metals, and wastewater compounds. This report describes the study design, and the sampling and analytical methods, and presents the results for the second and third years of the study (October 1999 to September 2001). Data collected during the first year of sampling (October 1998 to September 1999) were published in 2002.

Continuous, high-flux and efficient oil/water separation assisted by an integrated system with opposite wettability

NASA Astrophysics Data System (ADS)

Li, Jian; Long, Yifei; Xu, Changcheng; Tian, Haifeng; Wu, Yanxia; Zha, Fei

2018-03-01

To resolve the drawbacks that single-mesh involved for oil/water separation, such as batch processing mode, only one phase was purified and the quick decrease in flux et al., herein, a two-way separation T-tube device was designed by integrating a pair of meshes with opposite wettability, i.e., underwater superoleophobic and superhydrophobic/superoleophilic properties. Such integrated system can continuously separate both oil and water phase from the oil/water mixtures simultaneously through one-step procedure with high flux (above 3.675 L m-2 s-1) and high separation efficiency larger than 99.8% regardless of the heavy oil or light oil involved in the mixture. Moreover, the as-prepared two meshes still maintained high separation efficiency larger than above 98.9% even after 50 cycle-usages. It worthy mentioned that this two-way separation mode essentially solves the oil liquid accumulation problem that is the single separation membrane needs to tolerate a large hydrostatic pressure caused by the accumulated liquid. We deeply believe this two-way separation system would provide a new strategy for realizing practical applications in oil spill clean-up via a continuous mode.

Theory of microemulsions in a gravitational field

NASA Technical Reports Server (NTRS)

Jeng, J. F.; Miller, Clarence A.

1989-01-01

A theory of microemulsions developed previously is extended to include the effect of a gravitational field. It predicts variation with position of drop size, drop volume fraction, and area per molecule in the surfactant films within a microemulsion phase. Variation in volume fraction is greatest and occurs in such a way that oil content increases with increasing elevation, as has been found experimentally. Large composition variations are predicted within a middle phase microemulsion near optimal conditions because inversion from the water-continuous to the oil-continuous arrangement occurs with increasing elevation. Generally speaking, gravity reduces solubilization within microemulsions and promotes separation of excess phases.

Graft polymerization of wood sawdust and peat with ethylene carbonate. A novel method for the preparation of supports with enhanced mechanical properties to be used in biofiltration of organic vapors.

PubMed

Hernández-Meléndez, O; Peydecastaing, J; Bárzana, E; Vaca-Garcia, C; Hernández-Luna, M; Borredon, M E

2009-01-01

The graft polymerization reaction between ethylene carbonate (EC) and scots pine sawdust (SPS) or peat moss (PM) offers a solvent-free approach to the simple and inexpensive aliphatic derivatization of these lignocellulosic fibers. This reaction was studied with liquid or vapor EC phases in three different reactor configurations: batch stirred (BSR), semi-continuous stirred (SSR) and continuous tubular in the gas phase (CVTR). The use of a vapor phase allowed a satisfactory grafting yield and minimal production of non-grafted polyol by-products. The crosslinking agent 4,4'-methylenebis(phenylisocyanate) (MDI) achieved superior characteristics to form shaped tablets resistant to water disaggregation, a high water retention capacity and high compression strength, characteristics that conventional organic supports like PM or PM-polyurethane foam mixtures used in biofiltration of waste gases do not completely possess.

77 FR 53231 - Final Environmental Impact Statement for the Odessa Subarea Special Study-Columbia Basin Project...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-31

... scope of the action alternative which include acreage, water supply, and general site locations would... authorized boundary with a surface water supply as part of continued phased development of the CBP. The... alternative impacts considered in the Draft EIS. Two water supply options are being considered that would use...

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

Burkholder, Michael B.; Litster, Shawn, E-mail: litster@andrew.cmu.edu

In this study, we analyze the stability of two-phase flow regimes and their transitions using chaotic and fractal statistics, and we report new measurements of dynamic two-phase pressure drop hysteresis that is related to flow regime stability and channel water content. Two-phase flow dynamics are relevant to a variety of real-world systems, and quantifying transient two-phase flow phenomena is important for efficient design. We recorded two-phase (air and water) pressure drops and flow images in a microchannel under both steady and transient conditions. Using Lyapunov exponents and Hurst exponents to characterize the steady-state pressure fluctuations, we develop a new, measurablemore » regime identification criteria based on the dynamic stability of the two-phase pressure signal. We also applied a new experimental technique by continuously cycling the air flow rate to study dynamic hysteresis in two-phase pressure drops, which is separate from steady-state hysteresis and can be used to understand two-phase flow development time scales. Using recorded images of the two-phase flow, we show that the capacitive dynamic hysteresis is related to channel water content and flow regime stability. The mixed-wettability microchannel and in-channel water introduction used in this study simulate a polymer electrolyte fuel cell cathode air flow channel.« less

Transitional phase inversion of emulsions monitored by in situ near-infrared spectroscopy.

PubMed

Charin, R M; Nele, M; Tavares, F W

2013-05-21

Water-heptane/toluene model emulsions were prepared to study emulsion transitional phase inversion by in situ near-infrared spectroscopy (NIR). The first emulsion contained a small amount of ionic surfactant (0.27 wt % of sodium dodecyl sulfate) and n-pentanol as a cosurfactant. In this emulsion, the study was guided by an inversion coordinate route based on a phase behavior study previously performed. The morphology changes were induced by rising aqueous phase salinity in a "steady-state" inversion protocol. The second emulsion contained a nonionic surfactant (ethoxylated nonylphenol) at a concentration of 3 wt %. A continuous temperature change induced two distinct transitional phase inversions: one occurred during the heating of the system and another during the cooling. NIR spectroscopy was able to detect phase inversion in these emulsions due to differences between light scattered/absorbed by water in oil (W/O) and oil in water (O/W) morphologies. It was observed that the two model emulsions exhibit different inversion mechanisms closely related to different quantities of the middle phases formed during the three-phase behavior of Winsor type III.

Influence of Sodium Chloride on the Formation and Dissociation Behavior of CO2 Gas Hydrates

PubMed Central

2017-01-01

We present an experimental study on the formation and dissociation characteristics of carbon dioxide (CO2) gas hydrates using Raman spectroscopy. The CO2 hydrates were formed from sodium chloride/water solutions with salinities of 0–10 wt %, which were pressurized with liquid CO2 in a stirred vessel at 6 MPa and a subcooling of 9.5 K. The formation of the CO2 hydrate resulted in a hydrate gel where the solid hydrate can be considered as the continuous phase that includes small amounts of a dispersed liquid water-rich phase that has not been converted to hydrate. During the hydrate formation process we quantified the fraction of solid hydrate, xH, and the fraction of the dispersed liquid water-rich phase, xL, from the signature of the hydroxyl (OH)-stretching vibration of the hydrate gel. We found that the fraction of hydrate xH contained in the hydrate gel linearly depends on the salinity of the initial liquid water-rich phase. In addition, the ratio of CO2 and water was analyzed in the liquid water-rich phase before hydrate formation, in the hydrate gel during growth and dissociation, and after its complete dissociation again in the liquid water-rich phase. We observed a supersaturation of CO2 in the water-rich phase after complete dissociation of the hydrate gel and were able to show that the excess CO2 exists as dispersed micro- or nanoscale liquid droplets in the liquid water-rich phase. These residual nano- and microdroplets could be a possible explanation for the so-called memory effect. PMID:28817275

Convective heat transfer measurements in a vapour-liquid-liquid three-phase direct contact heat exchanger

NASA Astrophysics Data System (ADS)

Mahood, Hameed B.; Campbell, A. N.; Baqir, Ali Sh.; Sharif, A. O.; Thorpe, R. B.

2018-06-01

Energy usage is increasing around the world due to the continued development of technology, and population growth. Solar energy is a promising low-grade energy resource that can be harvested and utilised in different applications, such solar heater systems, which are used in both domestic and industrial settings. However, the implementation of an efficient energy conversion system or heat exchanger would enhance such low-grade energy processes. The direct contact heat exchanger could be the right choice due to its ability to efficiently transfer significant amounts of heat, simple design, and low cost. In this work, the heat transfer associated with the direct contact condensation of pentane vapour bubbles in a three-phase direct contact condenser is investigated experimentally. Such a condenser could be used in a cycle with a solar water heater and heat recovery systems. The experiments on the steady state operation of the three-phase direct contact condenser were carried out using a short Perspex tube of 70 cm in total height and an internal diameter of 4 cm. Only a height of 48 cm was active as the direct contact condenser. Pentane vapour, (the dispersed phase) with three different initial temperatures (40° C, 43.5° C and 47.5° C) was directly contacted with water (the continuous phase) at 19° C. The experimental results showed that the total heat transfer rate per unit volume along the direct contact condenser gradually decreased upon moving higher up the condenser. Additionally, the heat transfer rate increases with increasing mass flow rate ratio, but no significant effect on the heat transfer rate of varying the initial temperature of the dispersed phase was seen. Furthermore, both the outlet temperature of the continuous phase and the void fraction were positively correlated with the total heat transfer rate per unit volume, with no considerable effect of the initial temperature difference between the dispersed and continuous phases.

Convective heat transfer measurements in a vapour-liquid-liquid three-phase direct contact heat exchanger

NASA Astrophysics Data System (ADS)

Mahood, Hameed B.; Campbell, A. N.; Baqir, Ali Sh.; Sharif, A. O.; Thorpe, R. B.

2017-12-01

Energy usage is increasing around the world due to the continued development of technology, and population growth. Solar energy is a promising low-grade energy resource that can be harvested and utilised in different applications, such solar heater systems, which are used in both domestic and industrial settings. However, the implementation of an efficient energy conversion system or heat exchanger would enhance such low-grade energy processes. The direct contact heat exchanger could be the right choice due to its ability to efficiently transfer significant amounts of heat, simple design, and low cost. In this work, the heat transfer associated with the direct contact condensation of pentane vapour bubbles in a three-phase direct contact condenser is investigated experimentally. Such a condenser could be used in a cycle with a solar water heater and heat recovery systems. The experiments on the steady state operation of the three-phase direct contact condenser were carried out using a short Perspex tube of 70 cm in total height and an internal diameter of 4 cm. Only a height of 48 cm was active as the direct contact condenser. Pentane vapour, (the dispersed phase) with three different initial temperatures (40° C, 43.5° C and 47.5° C) was directly contacted with water (the continuous phase) at 19° C. The experimental results showed that the total heat transfer rate per unit volume along the direct contact condenser gradually decreased upon moving higher up the condenser. Additionally, the heat transfer rate increases with increasing mass flow rate ratio, but no significant effect on the heat transfer rate of varying the initial temperature of the dispersed phase was seen. Furthermore, both the outlet temperature of the continuous phase and the void fraction were positively correlated with the total heat transfer rate per unit volume, with no considerable effect of the initial temperature difference between the dispersed and continuous phases.

New test for oil soluble/water dispersible gas pipeline inhibitors

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

Stegmann, D.W.; Asperger, R.G.

1987-01-01

The wheel test provides good mixing of the condensate and water phases, the coupons are exposed to both phases. Therefore, the wheel test cannot distinguish between inhibitors that need continuous mixing of the these phases to maintain a water dispersion of the inhibitor and inhibitors that will self disperse into the water. This concept becomes important for pipelines in stratified flow where the water can settle out. In these cases with low turbulence, the inhibitor must self disperse into the water to be effective. The paper describes a test method to measure the effectiveness of an inhibitor and its abilitymore » to self disperse. The effectiveness of several inhibitors as predicted by the new test method is discussed relative to data from the wheel test and breaker tests. Field performance of these inhibitors in a gas gathering line, with liquids in stratified flow, are cities and compared with the results of the various laboratory tests.« less

INTRINSIC BIOREMEDIATION OF FUEL CONTAMINATION IN GROUND WATER AT A FIELD SITE

EPA Science Inventory

A spill of gasoline occurred at an automobile service station in 1986. Oily phase residue in the subsurface has continued for the past 8 yr to release water soluble fuel hydrocarbons into the aquifer. The site was characterized for implementation of intrinsic remediation. The sub...

A microfluidic device for open loop stripping of volatile organic compounds.

PubMed

Cvetković, Benjamin Z; Dittrich, Petra S

2013-03-01

The detection of volatile organic compounds is of great importance for assessing the quality of water. In this contribution, we describe a miniaturized stripping device that allows fast online detection of organic solvents in water. The core component is a glass microfluidic chip that facilitates the creation of an annular-flowing stream of water and nitrogen gas. Volatile compounds are transferred efficiently from the water into the gas phase along the microfluidic pathway at room temperature within less than 5 s. Before exiting the microchip, the liquid phase is separated from the enriched gas phase by incorporating side capillaries through which the hydrophilic water phase is withdrawn. The gas phase is conveniently collected at the outlet reservoir by tubing. Finally, a semiconductor gas sensor analyzes the concentration of (volatile) organic compounds in the nitrogen gas. The operation and use of the stripping device is demonstrated for the organic solvents THF, 1-propanol, toluene, ethylbenzene, benzaldehyde, and methanol. The mobile, inexpensive, and continuously operating system with liquid flow rates in the low range of microliters per minute can be connected to other detectors or implemented in chemical production line for process control.

A multi-module microfluidic platform for continuous pre-concentration of water-soluble ions and separation of oil droplets from oil-in-water (O/W) emulsions using a DC-biased AC electrokinetic technique.

PubMed

Das, Dhiman; Phan, Dinh-Tuan; Zhao, Yugang; Kang, Yuejun; Chan, Vincent; Yang, Chun

2017-03-01

A novel continuous flow microfluidic platform specifically designed for environmental monitoring of O/W emulsions during an aftermath of oil spills is reported herein. Ionized polycyclic aromatic hydrocarbons which are toxic are readily released from crude oil to the surrounding water phase through the smaller oil droplets with enhanced surface area. Hence, a multi-module microfluidic device is fabricated to form ion enrichment zones in the water phase of O/W emulsions for the ease of detection and to separate micron-sized oil droplets from the O/W emulsions. Fluorescein ions in the water phase are used to simulate the presence of these toxic ions in the O/W emulsion. A DC-biased AC electric field is employed in both modules. In the first module, a nanoporous Nafion membrane is used for activating the concentration polarization effect on the fluorescein ions, resulting in the formation of stable ion enrichment zones in the water phase of the emulsion. A 35.6% amplification of the fluorescent signal is achieved in the ion enrichment zone; corresponding to 100% enrichment of the fluorescent dye concentration. In this module, the main inlet is split into two channels by using a Y-junction so that there are two outlets for the oil droplets. The second module located downstream of the first module consists of two oil droplet entrapment zones at two outlets. By switching on the appropriate electrodes, either one of the two oil droplet entrapment zones can be activated and the droplets can be blocked in the corresponding outlet. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Drowning-out crystallisation of sodium sulphate using aqueous two-phase systems.

PubMed

Taboada, M E; Graber, T A; Asenjo, J A; Andrews, B A

2000-06-23

A novel method to obtain crystals of pure, anhydrous salt, using aqueous two-phase systems was studied. A concentrated salt solution is mixed with polyethylene glycol (PEG), upon which three phases are formed: salt crystals, a PEG-rich liquid and a salt-rich liquid. After removal of the solid salt, a two-phase system is obtained. Both liquid phases are recycled, allowing the design of a continuous process, which could be exploited industrially. The phase diagram of the system water-Na2SO4-PEG 3350 at 28 degrees C was used. Several process alternatives are proposed and their economic potential is discussed. The process steps needed to produce sodium sulphate crystals include mixing, crystallisation, settling and, optionally, evaporation of water. The yield of sodium sulphate increases dramatically if an evaporation step is used.

National Program for Inspection of Non-Federal Dams. New Pond Dam (MA 00779), Massachusetts Coastal Basin, Easton, Massachusetts. Phase I Inspection Report.

DTIC Science & Technology

1981-07-01

formerly provided irrigation water for the Hammond-Fuller i cranberry bogs. At the present the reservoir continues to service some bogs approximately 2...there are few depressions or irregularities. Vegetation along the edges of the crest consist of short brush, scattered trees up to 22 in. diameter...dam formerly provided irrigation water for cranberry bogs downstream and continues to service some bogs although the owners of the bogs have no

Water quality monitoring of Sweetwater and Loveland reservoirs--Phase one results 1998-1999

USGS Publications Warehouse

Majewski, Michael S.; Sidhu, Jagdeep S.; Mendez, Gregory O.

2002-01-01

In 1998, the U.S. Geological Survey began a study to assess the overall health of the watershed feeding the Sweetwater Reservoir in southern San Diego County, California. The study focussed on monitoring for organic chemical contamination and the effects of construction and operation of State Route 125 on water quality. Three environmental compartments (air, water, and bed sediments) are being sampled regularly for chemical contaminants, including volatile organic compounds, polynuclear aromatic hydrocarbons, polychlorinated biphenyls, pesticides, and major and trace elements. The study is divided into two phases. Phase I sampling is designed to establish baseline conditions for target compounds in terms of detection frequency and concentration in air, water, and bed sediments. Phase II sampling will continue at the established monitoring sites during and after construction of State Route 125 to assess chemical impact on water quality in the reservoir resulting from land-use changes and development in the watershed. This report describes the study design, the sampling and analytical methods, and presents the data results for the first year of the study, September 1998 to September 1999.

Long-term stability of crystal-stabilized water-in-oil emulsions.

PubMed

Ghosh, Supratim; Pradhan, Mamata; Patel, Tejas; Haj-Shafiei, Samira; Rousseau, Dérick

2015-12-15

The impact of cooling rate and mixing on the long-term kinetic stability of wax-stabilized water-in-oil emulsions was investigated. Four cooling/mixing protocols were investigated: cooling from 45°C to either 25°C or 4°C with/without stirring and two cooling rates - slow (1°C/min) and fast (5°C/min). The sedimentation behaviour of the emulsions was significantly affected by cooling protocol. Stirring was critical to the stability of all emulsions, with statically-cooled (no stirring) emulsions suffering from extensive aqueous phase separation. Emulsions stirred while cooling showed sedimentation of a waxy emulsion layer leaving a clear oil layer at the top, with a smaller separation and droplet size distribution at 4°C compared to 25°C, indicating the importance of the amount of crystallized wax on emulsion stability. Light microscopy revealed that crystallized wax appeared both on the droplet surface and in the continuous phase, suggesting that stirring ensured dispersibility of the water droplets during cooling as the wax was crystallizing. Wax crystallization on the droplet surface provided stability against droplet coalescence while continuous phase wax crystals minimized inter-droplet collisions. The key novel aspect of this research is in the simplicity to tailor the spatial distribution of wax crystals, i.e., either at the droplet surface or in the continuous phase via use of a surfactant and judicious stirring and/or cooling. Knowledge gained from this research can be applied to develop strategies for long-term storage stability of crystal-stabilized W/O emulsions. Copyright © 2015 Elsevier Inc. All rights reserved.

Far-infrared spectral studies of phase changes in water ice induced by proton irradiation

NASA Technical Reports Server (NTRS)

Moore, Marla H.; Hudson, Reggie L.

1992-01-01

Changes in the FIR spectrum of crystalline and amorphous water ice as a function of temperature are reported. The dramatic differences between the spectra of these ices in the FIR are used to examine the effect of proton irradiation on the stability of the crystalline and amorphous ice phases from 13 to 77 K. In particular, the spectra near 13 K show interconversion between the amorphous and crystalline ice phases beginning at doses near 2 eV/molecule and continuing cyclically with increased dose. The results are used to estimate the stability of irradiated ices in astronomical environments.

Flexible echolocation behavior of trawling bats during approach of continuous or transient prey cues

PubMed Central

Übernickel, Kirstin; Tschapka, Marco; Kalko, Elisabeth K. V.

2013-01-01

Trawling bats use echolocation not only to detect and classify acoustically continuous cues originated from insects at and above water surfaces, but also to detect small water-dwelling prey items breaking the water surface for a very short time, producing only transient cues to be perceived acoustically. Generally, bats need to adjust their echolocation behavior to the specific task on hand, and because of the diversity of prey cues they use in hunting, trawling bats should be highly flexible in their echolocation behavior. We studied the adaptations in the behavior of Noctilio leporinus when approaching either a continuous cue or a transient cue that disappeared during the approach of the bat. Normally the bats reacted by dipping their feet in the water at the cue location. We found that the bats typically started to adapt their calling behavior at approximately 410 ms before prey contact in continuous cue trials, but were also able to adapt their approach behavior to stimuli onsets as short as 177 ms before contact, within a minimum reaction time of 50.9 ms in response to transient cues. In both tasks the approach phase ended between 32 and 53 ms before prey contact. Call emission always continued after the end of the approach phase until around prey contact. In some failed capture attempts, call emission did not cease at all after prey contact. Probably bats used spatial memory to dip at the original location of the transient cue after its disappearance. The duration of the pointed dips was significantly longer in transient cue trials than in continuous cue trials. Our results suggest that trawling bats possess the ability to modify their generally rather stereotyped echolocation behavior during approaches within very short reaction times depending on the sensory information available. PMID:23675352

Sorption-induced effects of humic substances on mass transfer of organic pollutants through aqueous diffusion boundary layers: the example of water/air exchange.

PubMed

Ramus, Ksenia; Kopinke, Frank-Dieter; Georgi, Anett

2012-02-21

This study examines the effect of dissolved humic substances (DHS) on the rate of water-gas exchange of organic compounds under conditions where diffusion through the aqueous boundary layer is rate-determining. A synthetic surfactant was applied for comparison. Mass-transfer coefficients were determined from the rate of depletion of the model compounds by means of an apparatus containing a stirred aqueous solution with continuous purging of the headspace above the solution. In addition, experiments with continuous passive dosing of analytes into the water phase were conducted to simulate a system where thermodynamic activity of the chemical in the aqueous phase is identical in the presence and absence of DHS. The experimental results show that DHS and surfactants can affect water-gas exchange rates by the superposition of two mechanisms: (1) hydrodynamic effects due to surface film formation ("surface smoothing"), and (2) sorption-induced effects. Whether sorption accelerates or retards mass transfer depends on its effect on the thermodynamic activity of the pollutant in the aqueous phase. Mass transfer will be retarded if the activity (or freely dissolved concentration) of the pollutant is decreased due to sorption. If it remains unchanged (e.g., due to fast equilibration with a sediment acting as a large source phase), then DHS and surfactant micelles can act as an additional shuttle for the pollutants, enhancing the flux through the boundary layer.

Effect of nanostructure on rapid boiling of water on a hot copper plate: a molecular dynamics study

NASA Astrophysics Data System (ADS)

Fu, Ting; Mao, Yijin; Tang, Yong; Zhang, Yuwen; Yuan, Wei

2016-08-01

Molecular dynamic simulations are performed to study the effects of nanostructure on rapid boiling of water that is suddenly heated by a hot copper plate. The results show that the nanostructure has significant effects on energy transfer from solid copper plate to liquid water and phase change process from liquid water to vapor. The liquid water on the solid surface rapidly boil after contacting with an extremely hot copper plate and consequently a cluster of liquid water moves upward during phase change. The temperature of the water film when it separates from solid surface and its final temperature when the system is at equilibrium strongly depend on the size of the nanostructure. These temperatures increase with increasing size of nanostructure. Furthermore, a non-vaporized molecular layer is formed on the surface of the copper plate even continuous heat flux is passing into water domain through the plate.

Abnormal gas-liquid-solid phase transition behaviour of water observed with in situ environmental SEM.

PubMed

Chen, Xin; Shu, Jiapei; Chen, Qing

2017-04-24

Gas-liquid-solid phase transition behaviour of water is studied with environmental scanning electron microscopy for the first time. Abnormal phenomena are observed. At a fixed pressure of 450 Pa, with the temperature set to -7 °C, direct desublimation happens, and ice grows continuously along the substrate surface. At 550 Pa, although ice is the stable phase according to the phase diagram, metastable liquid droplets first nucleate and grow to ~100-200 μm sizes. Ice crystals nucleate within the large sized droplets, grow up and fill up the droplets. Later, the ice crystals grow continuously through desublimation. At 600 Pa, the metastable liquid grows quickly, with some ice nuclei floating in it, and the liquid-solid coexistence state exists for a long time. By lowering the vapour pressure and/or increasing the substrate temperature, ice sublimates into vapour phase, and especially, the remaining ice forms a porous structure due to preferential sublimation in the concave regions, which can be explained with surface tension effect. Interestingly, although it should be forbidden for ice to transform into liquid phase when the temperature is well below 0 °C, liquid like droplets form during the ice sublimation process, which is attributed to the surface tension effect and the quasiliquid layers.

In situ continuous derivatization/pre-concentration of carbonyl compounds with 2,4-dinitrophenylhydrazine in aqueous samples by solid-phase extraction Application to liquid chromatography determination of aldehydes.

PubMed

Baños, Clara-Eugenia; Silva, Manuel

2009-03-15

A rapid and straightforward continuous solid-phase extraction system has been developed for in situ derivatization and pre-concentration of carbonyl compounds in aqueous samples. Initially 2,4-dinitrophenylhydrazine, the derivatizing agent, was adsorbed on a C(18) mini-column and then 15-ml of sample were continuously aspirated into the flow system, where the derivatization and pre-concentration of the analytes (low-molecular mass aldehydes) were performed simultaneously. Following elution, 20 microl of the extract were injected into a LC-DAD system, in which hydrazones were successfully separated in 12 min on a RP-C(18) column using a linear gradient mobile phase of acetonitrile-water of 60-100% acetonitrile for 8 min, flowing at 0.5 ml/min. The whole analytical process can be accomplished within ca. 35 min. Under optimum conditions, limits of detection were obtained between 0.3 and 1.0 microg/l and RSDs (inter-day precision) from 1.2 to 4.6%. Finally, some applications on water samples are presented with recoveries ranged from 95.8 to 99.4%.

C1-Continuous relative permeability and hybrid upwind discretization of three phase flow in porous media

NASA Astrophysics Data System (ADS)

Lee, S. H.; Efendiev, Y.

2016-10-01

Three-phase flow in a reservoir model has been a major challenge in simulation studies due to slowly convergent iterations in Newton solution of nonlinear transport equations. In this paper, we examine the numerical characteristics of three-phase flow and propose a consistent, "C1-continuous discretization" (to be clarified later) of transport equations that ensures a convergent solution in finite difference approximation. First, we examine three-phase relative permeabilities that are critical in solving nonlinear transport equations. Three-phase relative permeabilities are difficult to measure in the laboratory, and they are often correlated with two-phase relative permeabilities (e.g., oil-gas and water-oil systems). Numerical convergence of non-linear transport equations entails that three-phase relative permeability correlations are a monotonically increasing function of the phase saturation and the consistency conditions of phase transitions are satisfied. The Modified Stone's Method II and the Linear Interpolation Method for three-phase relative permeability are closely examined for their mathematical properties. We show that the Linear Interpolation Method yields C1-continuous three-phase relative permeabilities for smooth solutions if the two phase relative permeabilities are monotonic and continuously differentiable. In the second part of the paper, we extend a Hybrid-Upwinding (HU) method of two-phase flow (Lee, Efendiev and Tchelepi, ADWR 82 (2015) 27-38) to three phase flow. In the HU method, the phase flux is divided into two parts based on the driving forces (in general, it can be divided into several parts): viscous and buoyancy. The viscous-driven and buoyancy-driven fluxes are upwinded differently. Specifically, the viscous flux, which is always co-current, is upwinded based on the direction of the total velocity. The pure buoyancy-induced flux is shown to be only dependent on saturation distributions and counter-current. In three-phase flow, the buoyancy effect can be expressed as a sum of two buoyancy effects from two-phase flows, i.e., oil-water and oil-gas systems. We propose an upwind scheme for the buoyancy flux term from three-phase flow as a sum of two buoyancy terms from two-phase flows. The upwind direction of the buoyancy flux in two phase flow is always fixed such that the heavier fluid goes downward and the lighter fluid goes upward. It is shown that the Implicit Hybrid-Upwinding (IHU) scheme for three-phase flow is locally conservative and produces physically-consistent numerical solutions. As in two phase flow, the primary advantage of the IHU scheme is that the flux of a fluid phase remains continuous and differentiable as the flow regime changes between co-current and counter-current conditions as a function of time, or (Newton) iterations. This is in contrast to the standard phase-potential-based upwinding scheme, in which the overall fractional-flow (flux) function is non-differentiable across the transition between co-current and counter-current flows.

Role of continuous phase protein, (-)-epigallocatechin-3-gallate and carrier oil on β-carotene degradation in oil-in-water emulsions.

PubMed

Liu, Lei; Gao, Yanxiang; McClements, David Julian; Decker, Eric Andrew

2016-11-01

The chemical instability of β-carotene limits its utilization as a nutraceutical ingredient in foods. In this research, the effect of continuous phase alpha-lactalbumin (α-LA) and (-)-epigallocatechin-3-gallate (EGCG) on β-carotene degradation in medium chain triacylglycerol (MCT)- and corn oil-in-water emulsions was examined. EGCG significantly inhibited β-carotene degradation in both MCT and corn oil-in-water emulsions in a dose dependent manner. α-LA was not able to protect β-carotene in MCT emulsions and the combination of EGCG and α-LA had a similar effect as EGCG alone. EGCG had no effect on lipid oxidation in corn oil-in-water emulsions but can protect β-carotene. β-Carotene was more stable in corn oil emulsions stabilized by α-LA compared to emulsions stabilized by Tween 20. These results show that EGCG is effective at protecting β-carotene in different emulsion systems without negatively impacting lipid oxidation suggesting that it could be utilized to increase the incorporation of β-carotene into food emulsions. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

Ortiz, E.; Kraatz, M.; Luthy, R.G.

The dissolution of naphthalene, phenanthrene, and pyrene from viscous organic phases into water was studied in continuous-flow systems for time periods ranging from several months to more than 1 year. By selecting nonaqueous phases ranging from low viscosity to semisolid, i.e., from a light lubricating oil to paraffin, the governance of mass transfer was shown to vary from water phase control to nonaqueous phase control. An advancing depleted-zone model is proposed to explain the dissolution of PAHs from a viscous organic phase wherein the formation of a depleted zone within the organic phase increases the organic phase resistance to themore » dissolution of PAHs. The experimental data suggest the formation of a depleted zone within the organic phase for systems comprising a high-viscosity oil, petrolatum (petroleum jelly), and paraffin. Organic phase resistance to naphthalene dissolution became dominant over aqueous phase resistance after flushing for several days. Such effects were not evident for low viscosity lubricating oil. The transition from aqueous-phase dissolution control to nonaqueous-phase dissolution control appears predictable, and this provides a more rational framework to assess long-term release of HOCs from viscous nonaqueous phase liquids and semisolids.« less

Study of microbial community and biodegradation efficiency for single- and two-phase anaerobic co-digestion of brown water and food waste.

PubMed

Lim, J W; Chen, C-L; Ho, I J R; Wang, J-Y

2013-11-01

The objective of this work was to study the microbial community and reactor performance for the anaerobic co-digestion of brown water and food waste in single- and two-phase continuously stirred tank reactors (CSTRs). Bacterial and archaeal communities were analyzed after 150 days of reactor operation. As compared to single-phase CSTR, methane production in two-phase CSTR was found to be 23% higher. This was likely due to greater extent of solubilization and acidification observed in the latter. These findings could be attributed to the predominance of Firmicutes and greater bacterial diversity in two-phase CSTR, and the lack of Firmicutes in single-phase CSTR. Methanosaeta was predominant in both CSTRs and this correlated to low levels of acetate in their effluent. Insights gained from this study would enhance the understanding of microorganisms involved in co-digestion of brown water and food waste as well as the complex biochemical interactions promoting digester stability and performance. Copyright © 2013 Elsevier Ltd. All rights reserved.

Microfluidic generation of particle-stabilized water-in-water emulsions

NASA Astrophysics Data System (ADS)

Abbasi, Niki; Navi, Maryam; Tsai, Scott

2017-11-01

We present a microfluidic platform that generates particle-stabilized water-in-water emulsions, using an aqueous two-phase system (ATPS) of polyethylene glycol (PEG) and Dextran (DEX). DEX droplets are generated passively at a flow focusing junction, in a continuous phase of PEG and carboxylated particles, using weak hydrostatic pressure to drive the flow. As DEX droplets travel inside the microfluidic device, carboxylated particles partition to the interface of the droplets. The number of particles partitioning to the interface of droplets increases as the droplets migrate downstream in the microchannel. As a result, the DEX droplets become stabilized against coalescence. We study the coverage and stability of the DEX droplets further downstream inside a reservoir, by changing the carboxylated particle concentration and the particle size. We anticipate that particle-stabilized water-in-water emulsions may have important biotechnological applications, due to their intrinsic biocompatibility compared to traditional particle-stabilized water-in-oil emulsions, for example for cell encapsulation.

Separation by solvent extraction

DOEpatents

Holt, Jr., Charles H.

1976-04-06

17. A process for separating fission product values from uranium and plutonium values contained in an aqueous solution, comprising adding an oxidizing agent to said solution to secure uranium and plutonium in their hexavalent state; contacting said aqueous solution with a substantially water-immiscible organic solvent while agitating and maintaining the temperature at from -1.degree. to -2.degree. C. until the major part of the water present is frozen; continuously separating a solid ice phase as it is formed; separating a remaining aqueous liquid phase containing fission product values and a solvent phase containing plutonium and uranium values from each other; melting at least the last obtained part of said ice phase and adding it to said separated liquid phase; and treating the resulting liquid with a new supply of solvent whereby it is practically depleted of uranium and plutonium.

Continued Water-Based Phase Change Material Heat Exchanger Development

NASA Technical Reports Server (NTRS)

Hansen, Scott; Poynot, Joe

2014-01-01

In a cyclical heat load environment such as low Lunar orbit, a spacecraft's radiators are not sized to reject the full heat load requirement. Traditionally, a supplemental heat rejection device (SHReD) such as an evaporator or sublimator is used to act as a "topper" to meet the additional heat rejection demands. Utilizing a Phase Change Material (PCM) heat exchanger (HX) as a SHReD provides an attractive alternative to evaporators and sublimators as PCM HXs do not use a consumable, thereby leading to reduced launch mass and volume requirements. In continued pursuit of water PCM HX development two full-scale, Orion sized water-based PCM HX's were constructed by Mezzo Technologies. These HX's were designed by applying prior research and experimentation to the full scale design. Design options considered included bladder restraint and clamping mechanisms, bladder manufacturing, tube patterns, fill/drain methods, manifold dimensions, weight optimization, and midplate designs. Design and construction of these HX's led to successful testing of both PCM HX's.

Wrapping with a splash: High-speed encapsulation with ultrathin sheets.

PubMed

Kumar, Deepak; Paulsen, Joseph D; Russell, Thomas P; Menon, Narayanan

2018-02-16

Many complex fluids rely on surfactants to contain, protect, or isolate liquid drops in an immiscible continuous phase. Thin elastic sheets can wrap liquid drops in a spontaneous process driven by capillary forces. For encapsulation by sheets to be practically viable, a rapid, continuous, and scalable process is essential. We exploit the fast dynamics of droplet impact to achieve wrapping of oil droplets by ultrathin polymer films in a water phase. Despite the violence of splashing events, the process robustly yields wrappings that are optimally shaped to maximize the enclosed fluid volume and have near-perfect seams. We achieve wrappings of targeted three-dimensional (3D) shapes by tailoring the 2D boundary of the films and show the generality of the technique by producing both oil-in-water and water-in-oil wrappings. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Anaerobic on-site black water and kitchen waste treatment using UASB-septic tanks at low temperatures.

PubMed

Luostarinen, S; Rintala, J

2006-01-01

Anaerobic on-site treatment of black water (BW) and a mixture of black water and kitchen waste (BWKW) was studied in a two-phased upflow anaerobic sludge blanket septic tank (UASBst) at 10-20 degrees C. The processes were fed either continuously or discontinuously (twice per weekday). Moreover, BWKW was post-treated for nitrogen removal in an intermittently aerated moving bed biofilm reactor (MBBR) at 20 degrees C. Removal of total chemical oxygen demand (COD1) was efficient at minimum 90% with all three UASBst at all temperatures. Removal of dissolved COD (CODdis) was also high at approx. 70% with continuously fed BW and discontinuously fed BWKW, while with discontinuous BW feeding it was 20%. Temperature decrease had little effect on COD removals, though the need for phase 2 increased with decreasing temperature, especially with BWKW. Post-treatment of BWKW in MBBR resulted in approx. 50% nitrogen removal, but suffered from lack of carbon for denitrification. With carbon addition, removal of ca. 83% was achieved.

In-lake carbon dioxide concentration patterns in four distinct phases in relation to ice cover dynamics

NASA Astrophysics Data System (ADS)

Denfeld, B. A.; Wallin, M.; Sahlee, E.; Sobek, S.; Kokic, J.; Chmiel, H.; Weyhenmeyer, G. A.

2014-12-01

Global carbon dioxide (CO2) emission estimates from inland waters include emissions at ice melt that are based on simple assumptions rather than evidence. To account for CO2 accumulation below ice and potential emissions into the atmosphere at ice melt we combined continuous CO2 concentrations with spatial CO2 sampling in an ice-covered small boreal lake. From early ice cover to ice melt, our continuous surface water CO2 concentration measurements at 2 m depth showed a temporal development in four distinct phases: In early winter, CO2 accumulated continuously below ice, most likely due to biological in-lake and catchment inputs. Thereafter, in late winter, CO2 concentrations remained rather constant below ice, as catchment inputs were minimized and vertical mixing of hypolimnetic water was cut off. As ice melt began, surface water CO2 concentrations were rapidly changing, showing two distinct peaks, the first one reflecting horizontal mixing of CO2 from surface and catchment waters, the second one reflecting deep water mixing. We detected that 83% of the CO2 accumulated in the water during ice cover left the lake at ice melt which corresponded to one third of the total CO2 storage. Our results imply that CO2 emissions at ice melt must be accurately integrated into annual CO2 emission estimates from inland waters. If up-scaling approaches assume that CO2 accumulates linearly under ice and at ice melt all CO2 accumulated during ice cover period leaves the lake again, present estimates may overestimate CO2 emissions from small ice covered lakes. Likewise, neglecting CO2 spring outbursts will result in an underestimation of CO2 emissions from small ice covered lakes.

Advanced Exploration Systems Water Architecture Study Interim Results

NASA Technical Reports Server (NTRS)

Sargusingh, Miriam J.

2013-01-01

The mission of the Advanced Exploration System (AES) Water Recovery Project (WRP) is to develop advanced water recovery systems that enable NASA human exploration missions beyond low Earth orbit (LEO). The primary objective of the AES WRP is to develop water recovery technologies critical to near-term missions beyond LEO. The secondary objective is to continue to advance mid-readiness-level technologies to support future NASA missions. An effort is being undertaken to establish the architecture for the AES Water Recovery System (WRS) that meets both near- and long-term objectives. The resultant architecture will be used to guide future technical planning, establish a baseline development roadmap for technology infusion, and establish baseline assumptions for integrated ground and on-orbit Environmental Control and Life Support Systems definition. This study is being performed in three phases. Phase I established the scope of the study through definition of the mission requirements and constraints, as well as identifying all possible WRS configurations that meet the mission requirements. Phase II focused on the near-term space exploration objectives by establishing an International Space Station-derived reference schematic for long-duration (>180 day) in-space habitation. Phase III will focus on the long-term space exploration objectives, trading the viable WRS configurations identified in Phase I to identify the ideal exploration WRS. The results of Phases I and II are discussed in this paper.

AES Water Architecture Study Interim Results

NASA Technical Reports Server (NTRS)

Sarguisingh, Miriam J.

2012-01-01

The mission of the Advanced Exploration System (AES) Water Recovery Project (WRP) is to develop advanced water recovery systems in order to enable NASA human exploration missions beyond low earth orbit (LEO). The primary objective of the AES WRP is to develop water recovery technologies critical to near term missions beyond LEO. The secondary objective is to continue to advance mid-readiness level technologies to support future NASA missions. An effort is being undertaken to establish the architecture for the AES Water Recovery System (WRS) that meets both near and long term objectives. The resultant architecture will be used to guide future technical planning, establish a baseline development roadmap for technology infusion, and establish baseline assumptions for integrated ground and on-orbit environmental control and life support systems (ECLSS) definition. This study is being performed in three phases. Phase I of this study established the scope of the study through definition of the mission requirements and constraints, as well as indentifying all possible WRS configurations that meet the mission requirements. Phase II of this study focused on the near term space exploration objectives by establishing an ISS-derived reference schematic for long-duration (>180 day) in-space habitation. Phase III will focus on the long term space exploration objectives, trading the viable WRS configurations identified in Phase I to identify the ideal exploration WRS. The results of Phases I and II are discussed in this paper.

Liquid bridges at the root-soil interface

NASA Astrophysics Data System (ADS)

Carminati, Andrea; Benard, Pascal; Ahmed, Mutez; Zarebanadkouki, Mohsen

2017-04-01

The role of the root-soil interface on soil-plant water relations is unclear. Despite many experimental studies proved that the soil close to the root surface, the rhizosphere, has different properties compared to the adjacent bulk soil, the mechanisms underlying such differences are poorly understood and the implications for plant-water relations remain largely speculative. The objective of this contribution is to discuss the key elements affecting water dynamics in the rhizosphere. Special attention is dedicated to the role of mucilage exuded by roots in shaping the hydraulic properties of the rhizosphere. We identified three key properties: 1) mucilage adsorbs water decreasing its water potential; 2) mucilage decreases the surface tension of the soil solution; 3) mucilage increases the viscosity of the soil solution. These three properties determine the retention and spatial configuration of the liquid phase in porous media. The increase in viscosity and the decrease in surface tension (quantified by the Ohnesorge number) allow the persistence of long liquid filaments even at very negative water potentials. At high mucilage concentrations these filaments form a network that creates an additional matric potential and maintains the continuity of the liquid phase during drying. The biophysical interactions between mucilage and the pore space determine the physical properties of the rhizosphere. Mucilage forms a network that provides mechanical stability to soils upon drying and that maintains the continuity of the liquid phase across the soil-root interface. Such biophysical properties are functional to create an interconnected matrix that maintains the roots in contact with the soil, which is of particular importance when the soil is drying and the transpiration rate is high.

Reversed phase liquid chromatography with UV absorbance and flame ionization detection using a water mobile phase and a cyano propyl stationary phase Analysis of alcohols and chlorinated hydrocarbons.

PubMed

Quigley, W W; Ecker, S T; Vahey, P G; Synovec, R E

1999-10-01

The development of liquid chromatography with a commercially available cyano propyl stationary phase and a 100% water mobile phase is reported. Separations were performed at ambient temperature, simplifying instrumental requirements. Excellent separation efficiency using a water mobile phase was achieved, for example N=18 800, or 75 200 m(-1), was obtained for resorcinol, at a retention factor of k'=4.88 (retention time of 9.55 min at 1 ml min(-1) for a 25 cmx4.6 mm i.d. column, packed with 5 mum diameter particles with the cyano propyl stationary phase). A separation via reversed phase liquid chromatography (RP-LC) with a 100% water mobile phase of six phenols and related compounds was compared to a separation of the same compounds by traditional RP-LC, using octadecylsilane (ODS), i.e. C18, bound to silica and an aqueous mobile phase modified with acetonitrile. Nearly identical analysis time was achieved for the separation of six phenols and related compounds using the cyano propyl stationary phase with a 100% water mobile phase, as compared to traditional RP-LC requiring a relatively large fraction of organic solvent modifier in the mobile phase (25% acetonitrile:75% water). Additional understanding of the retention mechanism with the 100% water mobile phase was obtained by relating measured retention factors of aliphatic alcohols, phenols and related compounds, and chlorinated hydrocarbons to their octanol:water partition coefficients. The retention mechanism is found to be consistent with a RP-LC mechanism coupled with an additional retention effect due to residual hydroxyl groups on the cyano propyl stationary phase. Advantages due to a 100% water mobile phase for the chemical analysis of alcohol mixtures and chlorinated hydrocarbons are reported. By placing an absorbance detector in-series and preceding a novel drop interface to a flame ionization detector (FID), selective detection of a separated mixture of phenols and related compounds and aliphatic alcohols is achieved. The compound class of aliphatic alcohols is selectively and sensitively detected by the drop interface/FID, and the phenols and related compounds are selectively and sensitively detected by absorbance detection at 200 nm. The separation and detection of chlorinated hydrocarbons in a water sample matrix further illustrated the advantages of this methodology. The sensitivity and selectivity of the FID signal for the chlorinated hydrocarbons are significantly better than absorbance detection, even at 200 nm. This methodology is well suited to continuous and automated monitoring of water samples. The applicability of samples initially in an organic solvent matrix is explored, since an organic sample matrix may effect retention and efficiency. Separations in acetonitrile and isopropyl alcohol sample matrices compared well to separations with a water sample matrix.

Garden Banks 388 deepwater pipeline span avoidance

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

Davis, S.W.; Sawyer, M.A.; Kenney, T.D.

1995-12-31

This paper will describe the span avoidance measures taken for the installation of the Garden Banks 388 deepwater oil and gas gathering pipelines. The two 12 inch pipelines connect a shallow water facility in EI-315 to a deep water subsea template in GB-388. These pipelines run across the irregular continental slope typically found in moderate to deep water in the Gulf of Mexico. To minimize pipeline spans, steps were taken during design, survey, and installation phases of the project. During each phase, as additional information became available, analyses and resulting recommended approaches were refined. This continuity, seldom easily obtained, provedmore » beneficial in translating design work into field results.« less

Catalytic distillation water recovery subsystem

NASA Technical Reports Server (NTRS)

Budininkas, P.; Rasouli, F.

1985-01-01

An integrated engineering breadboard subsystem for the recovery of potable water from untreated urine based on the vapor phase catalytic ammonia removal was designed, fabricated and tested. Unlike other evaporative methods, this process catalytically oxidizes ammonia and volatile hydrocarbons vaporizing with water to innocuous products; therefore, no pretreatment of urine is required. Since the subsystem is fabricated from commercially available components, its volume, weight and power requirements are not optimized; however, it is suitable for zero-g operation. The testing program consists of parametric tests, one month of daily tests and a continuous test of 168 hours duration. The recovered water is clear, odorless, low in ammonia and organic carbon, and requires only an adjustment of its pH to meet potable water standards. The obtained data indicate that the vapor phase catalytic ammonia removal process, if further developed, would also be competitive with other water recovery systems in weight, volume and power requirements.

Hydrophilic microspheres from water-in-oil emulsions by the water diffusion technique.

PubMed

Trotta, Michele; Chirio, Daniela; Cavalli, Roberta; Peira, Elena

2004-08-01

In this study, we developed and evaluated a novel method to produce insulin-loaded hydrophilic microspheres allowing high encapsulation efficiency and the preservation of peptide stability during particle processing. The preparation method used the diffusion of water by an excess of solvent starting from a water-in-solvent emulsion. The water dispersed phase containing albumin or lactose, or albumin-lactose in different weight ratios, and insulin was emulsified in water-saturated triacetin with and without emulsifiers, producing a water-in-triacetin emulsion. An excess of triacetin was added to the emulsion so that water could be extracted into the continuous phase, allowing the insulin-loaded microsphere precipitation. Insulin stability within the microspheres after processing was evaluated by reverse-phase and size-exclusion high-performance liquid chromatography. The water diffusion extraction process provided spherical microparticles of albumin or albumin-lactose. The mean diameter of the microspheres prepared with or without emulsifiers ranged from 2 to 10 microm, and the encapsulation efficiency of insulin was between 60% and 75%, respectively. The analysis of microsphere content after processing showed that insulin did not undergo any chemical modification within microspheres. The use of lactose alone led to the formation of highly viscous droplets that coalesced during the purification step. The water extraction procedures successfully produced insulin-loaded hydrophilic microspheres allowing the preservation of peptide stability. The type of excipient and the size of the disperse phase of the primary w/o emulsion were crucial determinants of microsphere characteristics.

Preparation of Microcapsules Containing β-Carotene with Thermo Sensitive Curdlan by Utilizing Reverse Dispersion

PubMed Central

Taguchi, Yoshinari; Ono, Fumiyasu; Tanaka, Masato

2013-01-01

We have tried to microencapsulate β-carotene with curdlan of a thermogelation type polysaccharide. Microcapsules were prepared by utilizing reverse dispersion, in which salada oil was the continuous phase (O’) and the curdlan water slurry (W) was the dispersed phase. β-carotene (O) as a core material was broken into fine oil droplets in the dispersed phase to form the (O/W) dispersion. The (O/W) dispersion was poured in the continuous phase (O’) and stirred to form the (O/W)/O’ dispersion at room temperature and then, temperature of the dispersion was raised to 80 °C to prepare curdlan-microcapusles containing β-carotene. In this microencapsulation process, the concentrations of curdlan and oil soluble surfactant and the impeller speed to form the (O/W)/O’ dispersion were mainly changed stepwise. We were able to prepare microcapsules by the microencapsulation method adopted here. The content of core material was increased with the curdlan concentration and decreased with the impeller speed and the oil soluble surfactant concentration. With the curdlan concentration, the drying rate of microcapsules was decreased and the retention ability for water was increased due to the stable preservation of β-carotene. PMID:24300565

Mineralizing urban net-zero water treatment: Phase II field ...

EPA Pesticide Factsheets

Net-zero water (NZW) systems, or water management systems achieving high recycling rates and low residuals generation so as to avoid water import and export, can also conserve energy used to heat and convey water, while economically restoring local eco-hydrology. However, design and operating experience are extremely limited. The objective of this paper is to present the results of the second phase of operation of an advanced oxidation-based NZW pilot system designed, constructed, and operated for a period of two years, serving an occupied four-person apartment. System water was monitored, either continuously or thrice daily, for routine water quality parameters, minerals, and MicroTox® in-vitro toxicity, and intermittently for somatic and male-specific coliphage, adenovirus, Cryptosporidium, Giardia, emerging organic constituents (non-quantitative), and the Florida drinking water standards. All 115 drinking water standards with the exception of bromate were met in this phase. Neither virus nor protozoa were detected in the treated water, with the exception of measurement of adenovirus genome copies attributed to accumulation of inactive genetic material in hydraulic dead zones. Chemical oxygen demand was mineralized to 90% in treatment. Total dissolved solids were maintained at ∼500 mg/L at steady state, partially through aerated aluminum electrocoagulation. Bromate accumulation is projected to be controlled by aluminum electrocoagulation with separate dispo

Introduction of Monochloramine into a Municipal Water System: Impact on Colonization of Buildings by Legionella spp.

PubMed Central

Moore, Matthew R.; Pryor, Marsha; Fields, Barry; Lucas, Claressa; Phelan, Maureen; Besser, Richard E.

2006-01-01

Legionnaires' disease (LD) outbreaks are often traced to colonized potable water systems. We collected water samples from potable water systems of 96 buildings in Pinellas County, Florida, between January and April 2002, during a time when chlorine was the primary residual disinfectant, and from the same buildings between June and September 2002, immediately after monochloramine was introduced into the municipal water system. Samples were cultured for legionellae and amoebae using standard methods. We determined predictors of Legionella colonization of individual buildings and of individual sampling sites. During the chlorine phase, 19 (19.8%) buildings were colonized with legionellae in at least one sampling site. During the monochloramine phase, six (6.2%) buildings were colonized. In the chlorine phase, predictors of Legionella colonization included water source (source B compared to all others, adjusted odds ratio [aOR], 6.7; 95% confidence interval [CI], 2.0 to 23) and the presence of a system with continuously circulating hot water (aOR, 9.8; 95% CI, 1.9 to 51). In the monochloramine phase, there were no predictors of individual building colonization, although we observed a trend toward greater effectiveness of monochloramine in hotels and single-family homes than in county government buildings. The presence of amoebae predicted Legionella colonization at individual sampling sites in both phases (OR ranged from 15 to 46, depending on the phase and sampling site). The routine introduction of monochloramine into a municipal drinking water system appears to have reduced colonization by Legionella spp. in buildings served by the system. Monochloramine may hold promise as community-wide intervention for the prevention of LD. PMID:16391067

Reactor Experiments at the University of Minnesota.

DTIC Science & Technology

1987-07-15

metallurgy; zinc, zinc oxide; solar thermal,’ solar Pi% thermoelectrochemical’ water splitting, separation devices; reactors e, ? 20. AeSiRACT (Continue oe...reported. Water splitting, recovery of hydrogen 4. and sulfur from hydrogen sulfide, electrolysis of zinc oxide in vapor and liquid phases, oil...CH4-CO2 reforming process. 2. Hydrogen production from water and the production of hydrogen and sulfur (or ammonia and sulfuric acid) from H2S. 3

Metal-ion retention properties of water-soluble amphiphilic block copolymer in double emulsion systems (w/o/w) stabilized by non-ionic surfactants.

PubMed

Palencia, Manuel; Rivas, Bernabé L

2011-11-15

Metal-ion retention properties of water-soluble amphiphilic polymers in presence of double emulsion were studied by diafiltration. Double emulsion systems, water-in-oil-in-water, with a pH gradient between external and internal aqueous phases were prepared. A poly(styrene-co-maleic anhydride) (PSAM) solution at pH 6.0 was added to the external aqueous phase of double emulsion and by application of pressure a divalent metal-ion stream was continuously added. Metal-ions used were Cu(2+) and Cd(2+) at the same pH of polymer solution. According to our results, metal-ion retention is mainly the result of polymer-metal interaction. Interaction between PSMA and reverse emulsion globules is strongly controlled by amount of metal-ions added in the external aqueous phase. In addition, as metal-ion concentration was increased, a negative effect on polymer retention capacity and promotion of flocculation phenomena were produced. Copyright © 2011 Elsevier Inc. All rights reserved.

Biodegradation testing of chemicals with high Henry's constants - Separating mass and effective concentration reveals higher rate constants.

PubMed

Birch, Heidi; Andersen, Henrik R; Comber, Mike; Mayer, Philipp

2017-05-01

During simulation-type biodegradation tests, volatile chemicals will continuously partition between water phase and headspace. This study addressed how (1) this partitioning affects test results and (2) can be accounted for by combining equilibrium partition and dynamic biodegradation models. An aqueous mixture of 9 (semi)volatile chemicals was first generated using passive dosing and then diluted with environmental surface water producing concentrations in the ng/L to μg/L range. After incubation for 2 h to 4 weeks, automated Headspace Solid Phase Microextraction (HS-SPME) was applied directly on the test systems to measure substrate depletion by biodegradation relatively to abiotic controls. HS-SPME was also applied to determine air to water partitioning ratios. Biodegradation rate constants relating to the chemical in the water phase, k water , were generally a factor 1 to 11 times higher than biodegradation rate constants relating to the total mass of chemical in the test system, k system , with one exceptional factor of 72 times for a long chain alkane. True water phase degradation rate constants were found (i) more appropriate for risk assessment than test system rate constants, (ii) to facilitate extrapolation to other air-water systems and (iii) to be better defined input parameters for aquatic exposure and fate models. Copyright © 2017 Elsevier Ltd. All rights reserved.

Numerical Modelling and Simulation of Chemical Reactions in a Nano-Pulse Discharged Bubble for Water Treatment

NASA Astrophysics Data System (ADS)

He, Yuchen; Satoshi, Uehara; Hidemasa, Takana; Hideya, Nishiyama

2016-09-01

A zero-dimensional model to simulate a nano-pulse-discharged bubble in water was developed. The model consists of gas and liquid phases corresponding to the inside and outside of the bubble, respectively. The diffusions of chemical species from the gas to the liquid phase through the bubble interface was also investigated. The initial gas is Ar, but includes a little H2O and O2 in the bubble. The time evolution of the OH concentration in the liquid phase was mainly investigated as an important species for water treatment. It was shown that OH was generated in the bubble and then diffused into the liquid. With the application of a continuous nano-pulse discharge, more OH radicals were generated as the frequency increased at a low voltage for a given power consumption. supported partially by Japan Society for the Promotion of Science (JSPS) KAKENHI (No. 26249015)

Improvements in ion reflux: An electrodialytic eluent generation and suppression device for ion chromatography.

PubMed

Elkin, Kyle; Riviello, John; Small, Hamish

2015-07-17

This work describes a membrane based electrodialytic ion reflux device (IRD), which uses water as the pumped phase and integrates isocratic and gradient eluent generation and suppression. The current design incorporates several ion exchange membranes to create discrete chambers for suppression and eluent generation, while isolating the electrodes from the analytical stream. A small volume of recycled water can be used as the pumped phase while continuously refluxing the eluent ions. This current design permits electronically controlled eluent generation of at least 16.4μeq KOHmin(-1), while maintaining low suppressed background conductivity (<0.5μS/cm). The device was operated in gradient or isocratic mode continuously for up to 6 weeks. During this period, over 500 gradient and isocratic injections were performed, showing peak retention time precision below 1.5% RSD. Published by Elsevier B.V.

Annual report, 1966-67, stream ecology phase of the Caspar Creek project

Treesearch

John W. DeWitt

1967-01-01

During the 1966 - June 30, 1967 fiscal year, calibration work on the stream ecology phase of the project continued along about the lines of last year's work. The emphasis was on determining the importance of stream canopy, particulary as it affects the amount of solar radiation being received at the water surface and on stream conditions influenced by the amount...

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…

Competence formation and post-graduate education in the public water sector in Indonesia

NASA Astrophysics Data System (ADS)

Kaspersma, J. M.; Alaerts, G. J.; Slinger, J. H.

2012-01-01

A framework is introduced, describing three aggregate competences for technical issues, management and governance, and a meta-competence for continuous learning and innovation, for the water sector. The four competences are further organised in a T-shaped competence profile. The framework and an assessment methodology were tested in a case study on post-graduate water education for professional staff in the Directorate General Water Resources (DGWR) in Indonesia. Though DGWR professionals have a firmly "technical" orientation, both the surveys and interviews show strong interest in the other competences: in particular the learning meta-competence, as well as the aggregate competence for management. The aggregate competence for governance systematically scores lower. A discrepancy appears to exist between the competences that staff perceive as needed in daily work, and those that could be acquired during post-graduate water education. In both locally-based and international post-graduate water education, the aggregate competences for management as well as governance are reportedly addressed modestly, if at all. With only little competence in these disciplines, it will be difficult for professionals to communicate and collaborate effectively in an interdisciplinary way. As a result, the horizontal bar of the T-shaped profile remains weakly developed. In international post-graduate education, this seems partly compensated by the attention for continuous learning and innovation. The exposure to a different culture and learning format is reported as fundamentally formative. The policies of DGWR have gone through three distinct phases. In the first phase (1970-1987) technical competence and learning were valued highly and training was arranged effectively; in the current phase the need to develop new competences is raising new challenges.

Study on preparation and formation mechanism of n-alkanol/water emulsion using alpha-cyclodextrin.

PubMed

Hashizaki, Kaname; Kageyama, Takashi; Inoue, Motoki; Taguchi, Hiroyuki; Ueda, Haruhisa; Saito, Yoshihiro

2007-11-01

Surfactants are usually used for the preparation of emulsions; however, some have an adverse effect on the human body such as skin irritation, hemolysis, and protein denaturation, etc. In this study, we examined the preparation and formation mechanism of n-alkanol/water emulsions using alpha-cyclodextrin (alpha-CD) as an emulsifier. Emulsions were prepared by mixing oil and water phases for 4 min at 2500 rpm using a vortex mixer. The mechanism of emulsification was investigated with some physico-chemical techniques. From phase diagrams of n-alkanol/alpha-CD/water systems, the emulsion phase extended as the chain length of n-alkanols and the amount of alpha-CD added increased. Furthermore, the emulsion was not formed in the region where the n-alkanol/alpha-CD complex didn't precipitate; however, the emulsion was formed in the region where the complex precipitated. In addition, it was clear that the emulsions have a yield stress value and correspond to the Maxwell model from rheological measurement. Our experiments clearly showed that the stable emulsions are formed because the precipitated complexes form a dense film at the oil-water interface and prevent aggregation among dispersed phases. Furthermore, it is suggested that the creation of a three-dimensional network structure formed by precipitated complexes in the continuous phase contributes to the stabilization of the emulsion. Thus, we concluded that the n-alkanol/water emulsions using alpha-cyclodextrin were a kind of the Pickering emulsion.

Micro-explosion of compound drops

NASA Astrophysics Data System (ADS)

Chen, Chun-Kuei; Lin, Ta-Hui

2014-08-01

Introducing water into spray combustion systems, by either water-in-oil emulsification or supplementary water injection, is one of the major techniques for combustion improvement and NOx reduction. Plentiful researches are available on combustion of water-in-oil emulsion fuel drops. The emulsified liquid is a heterogeneous mixture of immiscible liquids. One component forms the continuous phase and the other component forms the discrete phase. The discrete phase consists of globules of the one fluid that are suspended in the continuous phase fluid. Water-in-oil emulsions are commonly considered for combustion applications because emulsions can result in micro-explosion, thereby reducing the average drop diameter to enhance liquid vaporization, and suppressing the formation of soot and NOx. However, the water addition generally does not exceed about 20% for smooth engine operations[!, 21. The combustion characteristics and micro-explosion of emulsion drop were studied by many researchers. The micro-explosion of water in fuel emulsion drops was caused by very fast growth of superheated water vapor bubbles, its superheat limits must be lower than the boiling point temperature of the fuel. These bubbles were primarily governed by the pressure difference between the superheated vapor and the liquid, and by the inertia imparted to the liquid by the motion of the bubble surface[3 6 In this study, we used a coaxial nozzle to generation the multi-component drop. The different type of water-in-oil fuel drops called the compound drops. Unlike an emulsion drop, a compound drop consists of a water core and a fuel shell, which can originate from the phase separation of emulsion[7, 81 or a water drop colliding with a fuel drop[9, 101 Burning and micro-explosion of compound drops have been found to be distinct from those of emulsion drops[9-111 Wang et al.[9 , 101 studied the combustion characteristics of collision merged alkane-water drops. The merged drops appeared in adhesive and inserted manners. The drop ignition delay time increased with increasing water content. The average burning rate of alkane-water drops decreased with increasing water content. In the burning process, hexadecane-water drops exhibited flash vaporization or flame extinction. Heterogeneous explosion was occasionally observed in drops with trapped air bubbles. The air bubbles were assumed to be the nucleation points of the heterogeneous explosions. Chen and Lin[11 studied the characteristics of water-in-dodecane compound drop with different water content, diameter of drop and environmental oxygen concentration. The vaporization rate increased with increasing environmental oxygen concentration. The compound drops micro-exploded during the burning process in a random way. The number of micro-explosions was majorly influenced by drop diameter, followed by environmental oxygen concentration. Water content had a weaker effect on micro-explosion. As available literature and research results of compound drop burning are scarce, their combustion and micro-explosion behaviors are still poorly understood. In this regard, we changed the drop nature as compound drops to study their combustion characteristics and micro-explosion phenomena.

Comparison of Austenite Decomposition Models During Finite Element Simulation of Water Quenching and Air Cooling of AISI 4140 Steel

NASA Astrophysics Data System (ADS)

Babu, K.; Prasanna Kumar, T. S.

2014-08-01

An indigenous, non-linear, and coupled finite element (FE) program has been developed to predict the temperature field and phase evolution during heat treatment of steels. The diffusional transformations during continuous cooling of steels were modeled using Johnson-Mehl-Avrami-Komogorov equation, and the non-diffusion transformation was modeled using Koistinen-Marburger equation. Cylindrical quench probes made of AISI 4140 steel of 20-mm diameter and 50-mm long were heated to 1123 K (850 °C), quenched in water, and cooled in air. The temperature history during continuous cooling was recorded at the selected interior locations of the quench probes. The probes were then sectioned at the mid plane and resultant microstructures were observed. The process of water quenching and air cooling of AISI 4140 steel probes was simulated with the heat flux boundary condition in the FE program. The heat flux for air cooling process was calculated through the inverse heat conduction method using the cooling curve measured during air cooling of a stainless steel 304L probe as an input. The heat flux for the water quenching process was calculated from a surface heat flux model proposed for quenching simulations. The isothermal transformation start and finish times of different phases were taken from the published TTT data and were also calculated using Kirkaldy model and Li model and used in the FE program. The simulated cooling curves and phases using the published TTT data had a good agreement with the experimentally measured values. The computation results revealed that the use of published TTT data was more reliable in predicting the phase transformation during heat treatment of low alloy steels than the use of the Kirkaldy or Li model.

Process for photosynthetically splitting water

DOEpatents

Greenbaum, Elias

1984-01-01

The invention is an improved process for producing gaseous hydrogen and oxygen from water. The process is conducted in a photolytic reactor which contains a water-suspension of a photoactive material containing a hydrogen-liberating catalyst. The reactor also includes a volume for receiving gaseous hydrogen and oxygen evolved from the liquid phase. To avoid oxygen-inactivation of the catalyst, the reactor is evacuated continuously by an external pump which circulates the evolved gases through means for selectively recovering hydrogen therefrom. The pump also cools the reactor by evaporating water from the liquid phase. Preferably, product recovery is effected by selectively diffusing the hydrogen through a heated semipermeable membrane, while maintaining across the membrane a magnetic field gradient which biases the oxygen away from the heated membrane. This promotes separation, minimizes the back-reaction of hydrogen and oxygen, and protects the membrane.

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

Seamless Collapsible Fuel Tanks. Phase 1

DTIC Science & Technology

1982-03-01

TITLE (and Subtitle) 5. TYrE OF REPORT & PERIOD COVERED Final Report: Phase I Seamless Collapsible Fuel Tanks April 1980 - March 1982 6. PERFORMING...KEY WORDS (Continue on reverse side it neceessery nd identify by block number) tubular weaving, pillow tanks, fuel resistance , water resistance ...ends x 28 picks per inch in a plain or basket weave. The fabric is then coated both sides with an appropriate fuel- resistant compound, usually a nitrile

Highly Transparent w/o Pickering Emulsions without Adjusting the Refractive Index of the Stabilizing Particles.

PubMed

Sihler, Susanne; Lindén, Mika; Ziener, Ulrich

2017-10-03

Pickering emulsions with a remarkable transmittance of up to 86% across the visible spectrum have been prepared without adjusting the refractive index (RI) of the stabilizing particles to those of the aqueous and oil phases. Commercially available hydrophilic silica particles with a diameter of 20 nm, which are hydrophobized partially in situ, were used to stabilize water droplets with diameters below 400 nm in IsoparM. In this system, the stabilizing particles and the emulsion droplets act as one single scattering object, which renders RI-matching of the particles unnecessary. By either evaporation of some water from the droplets or addition of an appropriate organic liquid to the oil phase, it is possible to match the RI of the droplets (aqueous phase + particles) with that of the continuous phase, which minimizes scattering and results in highly transparent emulsions.

Continuously tunable microdroplet-laser in a microfluidic channel.

PubMed

Tang, Sindy K Y; Derda, Ratmir; Quan, Qimin; Lončar, Marko; Whitesides, George M

2011-01-31

This paper describes the generation and optical characterization of a series of dye-doped droplet-based optical microcavities with continuously decreasing radius in a microfluidic channel. A flow-focusing nozzle generated the droplets (~21 μm in radius) using benzyl alcohol as the disperse phase and water as the continuous phase. As these drops moved down the channel, they dissolved, and their size decreased. The emission characteristics from the drops could be matched to the whispering gallery modes from spherical micro-cavities. The wavelength of emission from the drops changed from 700 to 620 nm as the radius of the drops decreased from 21 μm to 7 μm. This range of tunability in wavelengths was larger than that reported in previous work on droplet-based cavities.

Effect of water on nanomechanics of bone is different between tension and compression

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

Samuel, Jitin; Park, Jun-Sang; Almer, Jonathan

Water, an important constituent in bone, resides in different compartments in bone matrix and may impose significant effects on its bulk mechanical properties. However, a clear understanding of the mechanistic role of water in toughening bone is yet to emerge. To address this issue, this study used a progressive loading protocol, coupled with measurements of in situ mineral and collagen fibril deformations using synchrotron X-ray diffraction techniques. Using this unique approach, the contribution of water to the ultrastructural behavior of bone was examined by testing bone specimens in different loading modes (tension and compression) and hydration states (wet and dehydrated).more » The results indicated that the effect of water on the mechanical behavior of mineral and collagen phases at the ultrastructural level was loading mode dependent and correlated with the bulk behavior of bone. Tensile loading elicited a transitional drop followed by an increase in load bearing by the mineral phase at the ultrastructural level, which was correlated with a strain hardening behavior of bone at the bulk level. Compression loading caused a continuous loss of load bearing by the mineral phase, which was reflected at the bulk level as a strain softening behavior. In addition, viscous strain relaxation and pre-strain reduction were observed in the mineral phase in the presence of water. Taken together, the results of this study suggest that water dictates the bulk behavior of bone by altering the interaction between mineral crystals and their surrounding matrix.« less

Calculations of absorbed fractions in small water spheres for low-energy monoenergetic electrons and the Auger-emitting radionuclides (123)Ι and (125)Ι.

PubMed

Bousis, Christos; Emfietzoglou, Dimitris; Nikjoo, Hooshang

2012-12-01

To calculate the absorbed fraction (AF) of low energy electrons in small tissue-equivalent spherical volumes by Monte Carlo (MC) track structure simulation and assess the influence of phase (liquid water versus density-scaled water vapor) and of the continuous-slowing-down approximation (CSDA) used in semi-analytic calculations. An event-by-event MC code simulating the transport of electrons in both the vapor and liquid phase of water using appropriate electron-water interaction cross sections was used to quantify the energy deposition of low-energy electrons in spherical volumes. Semi-analytic calculations within the CSDA using a convolution integral of the Howell range-energy expressions are also presented for comparison. The AF for spherical volumes of radii from 10-1000 nm are presented for monoenergetic electrons over the energy range 100-10,000 eV and the two Auger-emitting radionuclides (125)I and (123)I. The MC calculated AF for the liquid phase are found to be smaller than those of the (density scaled) gas phase by up to 10-20% for the monoenergetic electrons and 10% for the two Auger-emitters. Differences between the liquid-phase MC results and the semi-analytic CSDA calculations are up to ∼ 55% for the monoenergetic electrons and up to ∼ 35% for the two Auger-emitters. Condensed-phase effects in the inelastic interaction of low-energy electrons with water have a noticeable but relatively small impact on the AF for the energy range and target sizes examined. Depending on the electron energies, the semi-analytic approach may lead to sizeable errors for target sizes with linear dimensions below 1 micron.

Phase equilibria and formation of vesicles of dioleoylphosphatidylcholine in glycerol/water mixtures.

PubMed

Johansson, L B; Kalman, B; Wikander, G; Fransson, A; Fontell, K; Bergenståhl, B; Lindblom, G

1993-07-04

The lipid 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) forms a lamellar liquid crystalline phase (L alpha) in arbitrary mixtures of glycerol and water. The phase has been characterized by means of X-ray diffraction, 31P-NMR spectroscopy and differential scanning calorimetry (DSC). In the L alpha state, and for DOPC concentrations greater than 50% (w/w), the thickness of the lipid bilayer decreases, while the area of the polar head group increases with increasing glycerol concentration. The phase transition from gel to L alpha state occurs in the range of 240 to 260 K. Contrary to a previous (McDaniel, R.V., McIntosh, T.J. and Simon, S.A. (1983) Biochim. Biophys. Acta 731, 97) study of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) we find that in the gel state, the thickness of the DOPC lipid bilayer is greater than that in the L alpha state. This suggests that in the gel state, the lipid acyl chains of DOPC are in extended configuration. The lamellar phase reaches its maximum swelling at about 50% (w/w) of DOPC. At lower DOPC concentrations a two-phase system is formed where the lamellar phase exists in equilibrium with excess of solvent. Unilamellar vesicles can be prepared from a diluted suspension of the lamellar phase either by using the sonicator or extruder technique. We show this by means of 31P-NMR, EPR and fluorescence spectroscopy. The mean radius of the vesicles, prepared by a sonicator, has been determined at different glycerol/water mixtures. It is found to decrease continuously from 100 A at 100% water to a minimum of 75 A at about 50% water in the solvent mixture. By further decreasing the water content in the solution, the radius rapidly increases, and a mean radius of 450 A is estimated at a water content of 10%. The rotational relaxation times of a fluorescent probe and two EPR spin probes, solubilized in DOPC vesicles, have been measured at different glycerol/water mixtures. It is found that the rotational rates are always much slower in the systems containing glycerol.

Spontaneous Growth and Mobilization of a Gas Phase in the Presence of Dense Non- Aqueous Phase Liquid (DNAPL)

NASA Astrophysics Data System (ADS)

Roy, J. W.; Smith, J. E.

2006-12-01

A number of mechanisms can lead to the presence of disconnected bubbles or ganglia of gas phase in groundwater. When associated with or near a DNAPL phase, the disconnected gas phase experiences mass transfer of dissolved gases including the volatile components of the DNAPL. The properties of the gas phase interface, such as interfacial tension and contact angle, can also be affected. This work addresses the behavior of spontaneous continual growth of initially trapped seed gas bubbles within DNAPL source zones. Three different experiments were performed in a 2-dimensional transparent flow cell 15 cm by 20 cm by 1.5 cm. In each case, a DNAPL pool was created within larger glass beads over smaller glass beads that served as a capillary barrier. The DNAPL consisted of either a 1:2 (v/v) tetrachloroethene (PCE) to benzene mixture, single component PCE, or single component TCE. The experiments effectively demonstrate spontaneous gas phase expansion and vertical advective mobilization of gas bubbles and ganglia above the DNAPL source zone. A cycle of gas phase growth and mobilization was facilitated by the presence of secondary seed bubbles left behind due to snap-off during vertical bubble (ganglion) mobilization. This gas phase growth process was relatively slow but continuous and could be expected to continue until the NAPL is completely dissolved. Some implications of the demonstrated behavior for water flow and mass transfer within and near the DNAPL source zone are highlighted.

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

NASA Astrophysics Data System (ADS)

Carter, J.; Dennis, K.

2013-12-01

Measuring the stable isotopes of liquid water (δ18O and δD) is a tool familiar to many Earth scientists, but most current techniques require discrete sampling. For example, isotope ratio mass spectrometry requires the collection of aliquots of water that are then converted to CO2, CO or H2 for analysis. Similarly, laser-based techniques, such as Cavity Ring-Down Spectroscopy (CRDS) convert discrete samples (typically < 2μL) of liquid water to water vapor using a flash vaporization process. By requiring the use of discrete samples fine-scale spatial and temporal studies of changes in δ18O and δD are limited. Here we present a continuous-flow water sampler that will enable scientists to probe isotopic changes in real-time, with applications including, but not limited to, quantification of the 'amount effect' (Dansgaard, 1964) during an individual precipitation event or storm track, real-time mixing of water in river systems, and shipboard continuous water measurements (Munksgaard et al., 2012). Due to the inherent ability of CRDS to measure a continuous flow of water vapor it is an ideal candidate for interfacing with a continuous water sampling system. Here we present results from the first commercially available continuous-flow water sampler, developed by engineers at Picarro. This peripheral device is compatible with Picarro CRDS isotopic water analyzers, allowing real-time, continuous isotopic measurements of liquid water. The new device, which expands upon the design of Munskgaard et al. (2011), utilizes expanded polytetrafluoroethylene (ePTFE) membrane technology to continuously generate gas-phase water, while liquid water is pumped through the system. The water vapor subsequently travels to the CRDS analyzer where the isotopic ratios are measured and recorded. The generation of water vapor using membrane technology is sensitive to environmental conditions, which if not actively control, lead to sustainable experimental noise and drift. Consequently, our continuous-flow water sample employs active control for all pertinent parameters, significantly increasing its stability and usability. We will present data from controlled laboratory experiments demonstrating sample-to-sample precision and long-term stability. We will also show experimental data that highlights the instrumental sample-to-sample memory, which we have decreased significantly from previous implementations of this technology. Additionally, we will present field results from the Sacramento River, CA. Dansgaard, W. (1964) 'Stable isotopes in precipitation', Tellus, 16(4), p. 436-468. Munksgaard, N.C., Wurster, C.M., Bass, A., Zagorskis, I., and Bird, M.I. (2012) 'First continuous shipboard d18O and dD measurements in seawater by diffusion sampling--cavity ring-down spectrometry', Environmental Chemistry Letters, 10, p.301-307. Munksgaard, N.C., Wurster, C.M., and Bird, M.I., (2011), 'Continuous analysis of δ18O and δD values of water by diffusion sampling cavity ring-down spectrometry: a novel sampling device for unattended field monitoring of precipitation, ground and surface waters', Rapid Communications in Mass Spectrometry, 25, p. 3706-3712.

Determination of pesticides in waters by automatic on-line solid-phase extraction-capillary electrophoresis.

PubMed

Hinsmann, P; Arce, L; Ríos, A; Valcárcel, M

2000-01-07

The separation of seven pesticides by micellar electrokinetic capillary chromatography in spiked water samples is described, allowing the analysis of pesticides mixtures down to a concentration of 50 microg l(-1) in less than 13 min. Calibration, pre-concentration, elution and injection into the sample vial was carried out automatically by a continuous flow system (CFS) coupled to a capillary electrophoresis system via a programmable arm. The whole system was electronically coupled by a micro-processor and completely controlled by a computer. A C18 solid-phase mini-column was used for the pre-concentration, allowing a 12-fold enrichment (as an average value) of the pesticides from fortified water samples. Under the optimal extraction conditions, recoveries between 90 and 114% for most of the pesticides were obtained.

Some Fundamental Experiments on Apparent Dissolution Rate of Gas Phase in the Groundwater Recovery Processes of the Geological Disposal System - 12146

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

Yoshii, Taiki; Niibori, Yuichi; Mimura, Hitoshi

The apparent dissolution rates of gas phase in the co-presence of solid phase were examined by in-room experiments in this study. The apparent dissolution rate of gas phase q (mol/m{sup 3}.s) was generally defined by q=aK{sub L}(γP{sub g}-c), where a (1/m) is specific surface area of the interface between gas and liquid phases, K{sub L} (m/s) is overall mass transfer coefficient, γ (mol/(Pa.m{sup 3})) is reciprocal number of Henry constant, P{sub g} (Pa) is partial pressure of gas phase, and c (mol/m{sup 3}) is the concentration of gas component in liquid phase. As a model gas, CO{sub 2} gas wasmore » used. For evaluating the values of K{sub L}, this study monitored pH or the migration rate of the interface between water/gas phases, using some experiments such as the packed beds and the micro channel consisting of granite chip and rubber sheet including a slit. In the results, the values of K{sub L} were distributed in the range from 5.0x10{sup -6} m/s to 5.0x10{sup -7} m/s. These values were small, in comparison with that (7.8x10{sup -4} m/s) obtained from the bubbling test where gas phase was continually injected into deionized water without solid phase. This means that the solid phase limits the local mixing of water phase near gas-liquid interfaces. (authors)« less

Thermal conductivity characteristics of dewatered sewage sludge by thermal hydrolysis reaction.

PubMed

Song, Hyoung Woon; Park, Keum Joo; Han, Seong Kuk; Jung, Hee Suk

2014-12-01

The purpose of this study is to quantify the thermal conductivity of sewage sludge related to reaction temperature for the optimal design of a thermal hydrolysis reactor. We continuously quantified the thermal conductivity of dewatered sludge related to the reaction temperature. As the reaction temperature increased, the dewatered sludge is thermally liquefied under high temperature and pressure by the thermal hydrolysis reaction. Therefore, the bound water in the sludge cells comes out as free water, which changes the dewatered sludge from a solid phase to slurry in a liquid phase. As a result, the thermal conductivity of the sludge was more than 2.64 times lower than that of the water at 20. However, above 200, it became 0.704 W/m* degrees C, which is about 4% higher than that of water. As a result, the change in physical properties due to thermal hydrolysis appears to be an important factor for heat transfer efficiency. Implications: The thermal conductivity of dewatered sludge is an important factor the optimal design of a thermal hydrolysis reactor. The dewatered sludge is thermally liquefied under high temperature and pressure by the thermal hydrolysis reaction. The liquid phase slurry has a higher thermal conductivity than pure water.

Hygroscopic behavior of atmospheric aerosols containing nitrate salts and water-soluble organic acids

NASA Astrophysics Data System (ADS)

Jing, Bo; Wang, Zhen; Tan, Fang; Guo, Yucong; Tong, Shengrui; Wang, Weigang; Zhang, Yunhong; Ge, Maofa

2018-04-01

While nitrate salts have critical impacts on environmental effects of atmospheric aerosols, the effects of coexisting species on hygroscopicity of nitrate salts remain uncertain. The hygroscopic behaviors of nitrate salt aerosols (NH4NO3, NaNO3, Ca(NO3)2) and their internal mixtures with water-soluble organic acids were determined using a hygroscopicity tandem differential mobility analyzer (HTDMA). The nitrate salt / organic acid mixed aerosols exhibit varying phase behavior and hygroscopic growth depending upon the type of components in the particles. Whereas pure nitrate salt particles show continuous water uptake with increasing relative humidity (RH), the deliquescence transition is still observed for ammonium nitrate particles internally mixed with organic acids such as oxalic acid and succinic acid with a high deliquescence point. The hygroscopicity of submicron aerosols containing sodium nitrate and an organic acid is also characterized by continuous growth, indicating that sodium nitrate tends to exist in a liquid-like state under dry conditions. It is observed that in contrast to the pure components, the water uptake is hindered at low and moderate RH for calcium nitrate particles containing malonic acid or phthalic acid, suggesting the potential effects of mass transfer limitation in highly viscous mixed systems. Our findings improve fundamental understanding of the phase behavior and water uptake of nitrate-salt-containing aerosols in the atmospheric environment.

Thermodynamics of water intrusion in nanoporous hydrophobic solids.

PubMed

Cailliez, Fabien; Trzpit, Mickael; Soulard, Michel; Demachy, Isabelle; Boutin, Anne; Patarin, Joël; Fuchs, Alain H

2008-08-28

We report a joint experimental and molecular simulation study of water intrusion in silicalite-1 and ferrerite zeolites. The main conclusion of this study is that water condensation takes place through a genuine first-order phase transition, provided that the interconnected pores structure is 3-dimensional. In the extreme confinement situation (ferrierite zeolite), condensation takes place through a continuous transition, which is explained by a shift of both the first-order transition line and the critical point with increasing confinement. The present findings are at odds with the common belief that conventional phase transitions cannot take place in microporous solids such as zeolites. The most important features of the intrusion/extrusion process can be understood in terms of equilibrium thermodynamics considerations. We believe that these findings are very general for hydrophobic solids, i.e. for both nonwetting as well as wetting water-solid interface systems.

Construction of a Direct Water-Injected Two-Stroke Engine for Phased Direct Fuel Injection-High Pressure Charging Investigations

NASA Technical Reports Server (NTRS)

Somsel, James P.

1998-01-01

The development of a water injected Orbital Combustion Process (OCP) engine was conducted to assess the viability of using the powerplant for high altitude NASA aircraft and General Aviation (GA) applications. An OCP direct fuel injected, 1.2 liter, three cylinder, two-stroke engine has been enhanced to independently inject water directly into the combustion chamber. The engine currently demonstrates low brake specific fuel consumption capability and an excellent power to weight ratio. With direct water injection, significant improvements can be made to engine power, to knock limits/ignition advance timing, and to engine NO(x) emissions. The principal aim of the testing was to validate a cyclic model developed by the Systems Analysis Branch at NASA Ames Research Center. The work is a continuation of Ames' investigations into a Phased Direct Fuel Injection Engine with High Pressure Charging (PDFI-ITPC).

Chemical reactions simulated by ground-water-quality models

USGS Publications Warehouse

Grove, David B.; Stollenwerk, Kenneth G.

1987-01-01

Recent literature concerning the modeling of chemical reactions during transport in ground water is examined with emphasis on sorption reactions. The theory of transport and reactions in porous media has been well documented. Numerous equations have been developed from this theory, to provide both continuous and sequential or multistep models, with the water phase considered for both mobile and immobile phases. Chemical reactions can be either equilibrium or non-equilibrium, and can be quantified in linear or non-linear mathematical forms. Non-equilibrium reactions can be separated into kinetic and diffusional rate-limiting mechanisms. Solutions to the equations are available by either analytical expressions or numerical techniques. Saturated and unsaturated batch, column, and field studies are discussed with one-dimensional, laboratory-column experiments predominating. A summary table is presented that references the various kinds of models studied and their applications in predicting chemical concentrations in ground waters.

Continuous Turbidity Monitoring in the Indian Creek Watershed, Tazewell County, Virginia, 2006-08

USGS Publications Warehouse

Moyer, Douglas; Hyer, Kenneth

2009-01-01

Thousands of miles of natural gas pipelines are installed annually in the United States. These pipelines commonly cross streams, rivers, and other water bodies during pipeline construction. A major concern associated with pipelines crossing water bodies is increased sediment loading and the subsequent impact to the ecology of the aquatic system. Several studies have investigated the techniques used to install pipelines across surface-water bodies and their effect on downstream suspended-sediment concentrations. These studies frequently employ the evaluation of suspended-sediment or turbidity data that were collected using discrete sample-collection methods. No studies, however, have evaluated the utility of continuous turbidity monitoring for identifying real-time sediment input and providing a robust dataset for the evaluation of long-term changes in suspended-sediment concentration as it relates to a pipeline crossing. In 2006, the U.S. Geological Survey, in cooperation with East Tennessee Natural Gas and the U.S. Fish and Wildlife Service, began a study to monitor the effects of construction of the Jewell Ridge Lateral natural gas pipeline on turbidity conditions below pipeline crossings of Indian Creek and an unnamed tributary to Indian Creek, in Tazewell County, Virginia. The potential for increased sediment loading to Indian Creek is of major concern for watershed managers because Indian Creek is listed as one of Virginia's Threatened and Endangered Species Waters and contains critical habitat for two freshwater mussel species, purple bean (Villosa perpurpurea) and rough rabbitsfoot (Quadrula cylindrical strigillata). Additionally, Indian Creek contains the last known reproducing population of the tan riffleshell (Epioblasma florentina walkeri). Therefore, the objectives of the U.S. Geological Survey monitoring effort were to (1) develop a continuous turbidity monitoring network that attempted to measure real-time changes in suspended sediment (using turbidity as a surrogate) downstream from the pipeline crossings, and (2) provide continuous turbidity data that enable the development of a real-time turbidity-input warning system and assessment of long-term changes in turbidity conditions. Water-quality conditions were assessed using continuous water-quality monitors deployed upstream and downstream from the pipeline crossings in Indian Creek and the unnamed tributary. These paired upstream and downstream monitors were outfitted with turbidity, pH (for Indian Creek only), specific-conductance, and water-temperature sensors. Water-quality data were collected continuously (every 15 minutes) during three phases of the pipeline construction: pre-construction, during construction, and post-construction. Continuous turbidity data were evaluated at various time steps to determine whether the construction of the pipeline crossings had an effect on downstream suspended-sediment conditions in Indian Creek and the unnamed tributary. These continuous turbidity data were analyzed in real time with the aid of a turbidity-input warning system. A warning occurred when turbidity values downstream from the pipeline were 6 Formazin Nephelometric Units or 15 percent (depending on the observed range) greater than turbidity upstream from the pipeline crossing. Statistical analyses also were performed on monthly and phase-of-construction turbidity data to determine if the pipeline crossing served as a long-term source of sediment. Results of this intensive water-quality monitoring effort indicate that values of turbidity in Indian Creek increased significantly between the upstream and downstream water-quality monitors during the construction of the Jewell Ridge pipeline. The magnitude of the significant turbidity increase, however, was small (less than 2 Formazin Nephelometric Units). Patterns in the continuous turbidity data indicate that the actual pipeline crossing of Indian Creek had little influence of downstream water quality; co

Fast Rotational Diffusion of Water Molecules in a 2D Hydrogen Bond Network at Cryogenic Temperatures

NASA Astrophysics Data System (ADS)

Prisk, T. R.; Hoffmann, C.; Kolesnikov, A. I.; Mamontov, E.; Podlesnyak, A. A.; Wang, X.; Kent, P. R. C.; Anovitz, L. M.

2018-05-01

Individual water molecules or small clusters of water molecules contained within microporous minerals present an extreme case of confinement where the local structure of hydrogen bond networks are dramatically altered from bulk water. In the zinc silicate hemimorphite, the water molecules form a two-dimensional hydrogen bond network with hydroxyl groups in the crystal framework. Here, we present a combined experimental and theoretical study of the structure and dynamics of water molecules within this network. The water molecules undergo a continuous phase transition in their orientational configuration analogous to a two-dimensional Ising model. The incoherent dynamic structure factor reveals two thermally activated relaxation processes, one on a subpicosecond timescale and another on a 10-100 ps timescale, between 70 and 130 K. The slow process is an in-plane reorientation of the water molecule involving the breaking of hydrogen bonds with a framework that, despite the low temperatures involved, is analogous to rotational diffusion of water molecules in the bulk liquid. The fast process is a localized motion of the water molecule with no apparent analogs among known bulk or confined phases of water.

Fast Rotational Diffusion of Water Molecules in a 2D Hydrogen Bond Network at Cryogenic Temperatures

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

Prisk, Timothy; Hoffmann, Christina; Kolesnikov, Alexander I.

Individual water molecules or small clusters of water molecules contained within microporous minerals present an extreme case of confinement where the local structure of hydrogen bond networks are dramatically altered from bulk water. In the zinc silicate hemimorphite, the water molecules form a two-dimensional hydrogen bond network with hydroxyl groups in the crystal framework. Here in this paper, we present a combined experimental and theoretical study of the structure and dynamics of water molecules within this network. The water molecules undergo a continuous phase transition in their orientational configuration analogous to a two-dimensional Ising model. The incoherent dynamic structure factormore » reveals two thermally activated relaxation processes, one on a subpicosecond timescale and another on a 10–100 ps timescale, between 70 and 130 K. The slow process is an in-plane reorientation of the water molecule involving the breaking of hydrogen bonds with a framework that, despite the low temperatures involved, is analogous to rotational diffusion of water molecules in the bulk liquid. The fast process is a localized motion of the water molecule with no apparent analogs among known bulk or confined phases of water.« less

Fast Rotational Diffusion of Water Molecules in a 2D Hydrogen Bond Network at Cryogenic Temperatures

DOE PAGES

Prisk, Timothy; Hoffmann, Christina; Kolesnikov, Alexander I.; ...

2018-05-09

Individual water molecules or small clusters of water molecules contained within microporous minerals present an extreme case of confinement where the local structure of hydrogen bond networks are dramatically altered from bulk water. In the zinc silicate hemimorphite, the water molecules form a two-dimensional hydrogen bond network with hydroxyl groups in the crystal framework. Here in this paper, we present a combined experimental and theoretical study of the structure and dynamics of water molecules within this network. The water molecules undergo a continuous phase transition in their orientational configuration analogous to a two-dimensional Ising model. The incoherent dynamic structure factormore » reveals two thermally activated relaxation processes, one on a subpicosecond timescale and another on a 10–100 ps timescale, between 70 and 130 K. The slow process is an in-plane reorientation of the water molecule involving the breaking of hydrogen bonds with a framework that, despite the low temperatures involved, is analogous to rotational diffusion of water molecules in the bulk liquid. The fast process is a localized motion of the water molecule with no apparent analogs among known bulk or confined phases of water.« less

Continuous low-level aquatic monitoring (CLAM) samplers for pesticide contaminant screening in urban runoff: Analytical approach and a field test case.

PubMed

Ensminger, Michael P; Vasquez, Martice; Tsai, Hsing-Ju; Mohammed, Sarah; Van Scoy, A; Goodell, Korena; Cho, Gail; Goh, Kean S

2017-10-01

Monitoring of surface waters for organic contaminants is costly. Grab water sampling often results in non-detects for organic contaminants due to missing a pulse event or analytical instrumentation limitations with a small sample size. Continuous Low-Level Aquatic Monitoring (CLAM) samplers (C.I.Agent ® Solutions) continually extract and concentrate organic contaminants in surface water onto a solid phase extraction disk. Utilizing CLAM samplers, we developed a broad spectrum analytical screen for monitoring organic contaminants in urban runoff. An intermediate polarity solid phase, hydrophobic/lipophilic balance (HLB), was chosen as the sorbent for the CLAM to target a broad range of compounds. Eighteen urban-use pesticides and pesticide degradates were targeted for analysis by LC/MS/MS, with recoveries between 59 and 135% in laboratory studies. In field studies, CLAM samplers were deployed at discrete time points from February 2015 to March 2016. Half of the targeted chemicals were detected with reporting limits up to 90 times lower than routine 1-L grab samples with good precision between field replicates. In a final deployment, CLAM samplers were compared to 1-L water samples. In this side-by-side comparison, imidacloprid, fipronil, and three fipronil degradates were detected by the CLAM sampler but only imidacloprid and fipronil sulfone were detected in the water samples. However, concentrations of fipronil sulfone and imidacloprid were significantly lower with the CLAM and a transient spike of diuron was not detected. Although the CLAM sampler has limitations, it can be a powerful tool for development of more focused and informed monitoring efforts based on pre-identified targets in the field. Copyright © 2017 Elsevier Ltd. All rights reserved.

Buckling failure of square ice-nanotube arrays constrained in graphene nanocapillaries.

PubMed

Zhu, YinBo; Wang, FengChao; Wu, HengAn

2016-08-07

Graphene confinement provides a new physical and mechanical environment with ultrahigh van der Waals pressure, resulting in new quasi-two-dimensional phases of few-layer ice. Polymorphic transition can occur in bilayer constrained water/ice system. Here, we perform a comprehensive study of the phase transition of AA-stacked bilayer water constrained within a graphene nanocapillary. The compression-limit and superheating-limit (phase) diagrams are obtained, based on the extensive molecular-dynamics simulations at numerous thermodynamic states. Liquid-to-solid, solid-to-solid, and solid-to-liquid-to-solid phase transitions are observed in the compression and superheating of bilayer water. Interestingly, there is a temperature threshold (∼275 K) in the compression-limit diagram, which indicates that the first-order and continuous-like phase transitions of bilayer water depend on the temperature. Two obviously different physical processes, compression and superheating, display similar structural evolution; that is, square ice-nanotube arrays (BL-VHDI) will bend first and then transform into bilayer triangular AA stacking ice (BL-AAI). The superheating limit of BL-VHDI exhibits local maxima, while that of BL-AAI increases monotonically. More importantly, from a mechanics point of view, we propose a novel mechanism of the transformation from BL-VHDI to BL-AAI, both for the compression and superheating limits. This structural transformation can be regarded as the "buckling failure" of the square-ice-nanotube columns, which is dominated by the lateral pressure.

Stabilization of NaCl-containing cuttings wastes in cement concrete by in situ formed mineral phases.

PubMed

Filippov, Lev; Thomas, Fabien; Filippova, Inna; Yvon, Jacques; Morillon-Jeanmaire, Anne

2009-11-15

Disposal of NaCl-containing cuttings is a major environmental concern due to the high solubility of chlorides. The present work aims at reducing the solubility of chloride by encapsulation in low permeability matrix as well as lowering its solubility by trapping into low-solubility phases. Both the studied materials were cuttings from an oil-based mud in oil drillings containing about 50% of halite, and cuttings in water-based mud from gas drilling containing 90% of halite. A reduction in the amount of dissolved salt from 41 to 19% according to normalized leaching tests was obtained by addition of potassium ortho-phosphate in the mortar formula of oil-based cuttings, while the aluminium dihydrogeno-phosphate is even more efficient for the stabilization of water-based cuttings with a NaCl content of 90%. Addition of ortho-phosphate leads to form a continuous and weakly soluble network in the cement matrix, which reduces the release of salt. The formed mineralogical phases were apatite and hydrocalumite. These phases encapsulate the salt grains within a network, thus lowering its interaction with water or/and trap chloride into low-solubility phases. The tested approaches allow to develop a confinement process of NaCl-containing waste of various compositions that can be applied to wastes, whatever the salt content and the nature of the drilling fluids (water or oil).

Development of a Compact and Efficient Ice Thermal Energy Storage Vessel

NASA Astrophysics Data System (ADS)

Sasaguchi, Kengo; Ishikawa, Masatoshi; Muta, Kenji; Yoshino, Kiyotaka; Hayashi, Hiroko; Baba, Yoshiyuki

In the present study, the authors propose the use of a low concentration aqueous solution as phase change material for static-type ice-storage-vessels, instead of pure water commonly used today. If an aqueous solution with low concentration is used, even when a large amount of solution (aqueous ethylene glycol in this study) is solidified and bridging of ice developed around cold tubes occurs, the pressure increase could be prevented by the existence of a continuous liquid phase in the solid-liquid two-phase layer (mushy layer) which opens to an air gap at the top of a vessel. Therefore, one can continue to solidify an aqueous solution after bridging, achieving a high ice packing factor (IPF). First, experiments using small-scale test cells have been conducted to confirm the present idea, and then we have performed experiments using a large vessel with an early practical size. It was seen that a large pressure increase is prevented for the initial concentration of the solution C0 of 1.0%, and IPF obtained using the solution is much greater than 0.65 using pure water for which the solidification must be stopped before the bridging.

Uses, funding, and availability of continuous streamflow data in Montana

USGS Publications Warehouse

Shields, R.R.; White, M.K.

1984-01-01

This report documents the results of a study of the uses, funding, and availability of continuous streamflow data collected and published by the U.S. Geological Survey in Montana. Data uses and funding sources are identified for the 218 continuous streamflow gages currently (1984) being operated. These stations are supported by 18 different funding sources at a budget for the 1984 water year of $1,065,000. The streamflow-gaging program in Montana has evolved through the years as Federal, State, and local needs for surface-water data have increased. Continuous streamflow records for periods ranging from less than 1 year to more than 90 years have been collected. This report describes phase 1 of a cost-effectiveness study of the streamflow-gaging program in Montana. Evaluation of the program indicates that numerous agencies use the data for studies involving regional hydrology, hydrologic systems, and planning and design. They also use the data for operations of existing hydroelectric and irrigation dams, forecasting flood and seasonal flows, water-quality monitoring, research studies for fish habitat, and other uses such as recreational management. (USGS)

Capturing Hot Moments of Carbon Cycling in the Hyporheic Zone of an Intermittent Stream

NASA Astrophysics Data System (ADS)

Brandt, T.; Harjung, A.; Vieweg, M.; Butturini, A.; Schmidt, C.; Fleckenstein, J. H.; Sabater, F.

2016-12-01

Intermittent streams are increasingly recognized as a factor for underestimating potential CO2 emissions of aquatic ecosystems, because they are neglected during their dry phase. This can be partly attributed to poor understanding of dissolved organic matter (DOM) processing at highly reactive interfaces such as the hyporheic zone (HZ). Here, hydrological transitions drive rapid changes in the spatiotemporal distribution of dissolved oxygen (DO), thus creating hot moments of increased biogeochemical cycling. However, capturing these process-dynamics requires a continuous monitoring of hyporheic pore water at a sufficient temporal and spatial resolution. In order to investigate the transitions between the wet and dry phase, we used a combination of automated pore water sampling and in situ measurements. By combining conventional pumping approaches with recently developed technology we achieved a high resolution multi-scale, quasi continuous monitoring of relevant parameters of the carbon cycle. Our novel approach coupled continuous fluorescence DOM and infrared CO2 sensor measurements with spatially continuous vertical oxygen profiling in situ. A proof-of-concept application was established in a semi-pristine Mediterranean stream during the drying period in summer 2015. Previous sampling campaigns already identified the water level as a driver of DOM composition in the HZ. Once the surface flow switches to subsurface flow, the HZ becomes a sink for aromatic, high molecular weight compounds, while protein-like, autochthonous DOM gets released. Generally, we observed exponential increases in hyporheic CO2 from this point on, co-occurring with a sharp vertical DO gradient as a function of changing hydrological conditions.

Effective Use of Household Water Treatment and Safe Storage in Response to the 2010 Haiti Earthquake

PubMed Central

Lantagne, Daniele; Clasen, Thomas

2013-01-01

When water supplies are compromised during an emergency, responders often recommend household water treatment and safe storage (HWTS) methods, such as boiling or chlorination. We evaluated the near- and longer-term impact of chlorine and filter products distributed shortly after the 2010 earthquake in Haiti. HWTS products were deemed as effective to use if they actually improved unsafe household drinking water to internationally accepted microbiological water quality standards. The acute emergency survey (442 households) was conducted within 8 weeks of emergency onset; the recovery survey (218 households) was conducted 10 months after onset. Effective use varied by HWTS product (from 8% to 63% of recipients in the acute phase and from 0% to 46% of recipients in the recovery phase). Higher rates of effective use were associated with programs that were underway in Haiti before the emergency, had a plan at initial distribution for program continuation, and distributed products with community health worker support and a safe storage container. PMID:23836571

Effect of hydrothermal liquefaction aqueous phase recycling on bio-crude yields and composition.

PubMed

Biller, Patrick; Madsen, René B; Klemmer, Maika; Becker, Jacob; Iversen, Bo B; Glasius, Marianne

2016-11-01

Hydrothermal liquefaction (HTL) is a promising thermo-chemical processing technology for the production of biofuels but produces large amounts of process water. Therefore recirculation of process water from HTL of dried distillers grains with solubles (DDGS) is investigated. Two sets of recirculation on a continuous reactor system using K2CO3 as catalyst were carried out. Following this, the process water was recirculated in batch experiments for a total of 10 rounds. To assess the effect of alkali catalyst, non-catalytic HTL process water recycling was performed with 9 recycle rounds. Both sets of experiments showed a large increase in bio-crude yields from approximately 35 to 55wt%. The water phase and bio-crude samples from all experiments were analysed via quantitative gas chromatography-mass spectrometry (GC-MS) to investigate their composition and build-up of organic compounds. Overall the results show an increase in HTL conversion efficiency and a lower volume, more concentrated aqueous by-product following recycling. Copyright © 2016 Elsevier Ltd. All rights reserved.

Analytical scaling relations to evaluate leakage and intrusion in intermittent water supply systems.

PubMed

Taylor, David D J; Slocum, Alexander H; Whittle, Andrew J

2018-01-01

Intermittent water supplies (IWS) deliver piped water to one billion people; this water is often microbially contaminated. Contaminants that accumulate while IWS are depressurized are flushed into customers' homes when these systems become pressurized. In addition, during the steady-state phase of IWS, contaminants from higher-pressure sources (e.g., sewers) may continue to intrude where pipe pressure is low. To guide the operation and improvement of IWS, this paper proposes an analytic model relating supply pressure, supply duration, leakage, and the volume of intruded, potentially-contaminated, fluids present during flushing and steady-state. The proposed model suggests that increasing the supply duration may improve water quality during the flushing phase, but decrease the subsequent steady-state water quality. As such, regulators and academics should take more care in reporting if water quality samples are taken during flushing or steady-state operational conditions. Pipe leakage increases with increased supply pressure and/or duration. We propose using an equivalent orifice area (EOA) to quantify pipe quality. This provides a more stable metric for regulators and utilities tracking pipe repairs. Finally, we show that the volume of intruded fluid decreases in proportion to reductions in EOA. The proposed relationships are applied to self-reported performance indicators for IWS serving 108 million people described in the IBNET database and in the Benchmarking and Data Book of Water Utilities in India. This application shows that current high-pressure, continuous water supply targets will require extensive EOA reductions. For example, in order to achieve national targets, utilities in India will need to reduce their EOA by a median of at least 90%.

Analytical scaling relations to evaluate leakage and intrusion in intermittent water supply systems

PubMed Central

Slocum, Alexander H.; Whittle, Andrew J.

2018-01-01

Intermittent water supplies (IWS) deliver piped water to one billion people; this water is often microbially contaminated. Contaminants that accumulate while IWS are depressurized are flushed into customers’ homes when these systems become pressurized. In addition, during the steady-state phase of IWS, contaminants from higher-pressure sources (e.g., sewers) may continue to intrude where pipe pressure is low. To guide the operation and improvement of IWS, this paper proposes an analytic model relating supply pressure, supply duration, leakage, and the volume of intruded, potentially-contaminated, fluids present during flushing and steady-state. The proposed model suggests that increasing the supply duration may improve water quality during the flushing phase, but decrease the subsequent steady-state water quality. As such, regulators and academics should take more care in reporting if water quality samples are taken during flushing or steady-state operational conditions. Pipe leakage increases with increased supply pressure and/or duration. We propose using an equivalent orifice area (EOA) to quantify pipe quality. This provides a more stable metric for regulators and utilities tracking pipe repairs. Finally, we show that the volume of intruded fluid decreases in proportion to reductions in EOA. The proposed relationships are applied to self-reported performance indicators for IWS serving 108 million people described in the IBNET database and in the Benchmarking and Data Book of Water Utilities in India. This application shows that current high-pressure, continuous water supply targets will require extensive EOA reductions. For example, in order to achieve national targets, utilities in India will need to reduce their EOA by a median of at least 90%. PMID:29775462

Continued Water-Based Phase Change Material Heat Exchanger Development

NASA Technical Reports Server (NTRS)

Hansen, Scott W.; Sheth, Rubik B.; Poynot, Joe; Giglio, Tony; Ungar, Gene K.

2015-01-01

In a cyclical heat load environment such as low Lunar orbit, a spacecraft's radiators are not sized to meet the full heat rejection demands. Traditionally, a supplemental heat rejection device (SHReD) such as an evaporator or sublimator is used to act as a "topper" to meet the additional heat rejection demands. Utilizing a Phase Change Material (PCM) heat exchanger (HX) as a SHReD provides an attractive alternative to evaporators and sublimators as PCM HX's do not use a consumable, thereby leading to reduced launch mass and volume requirements. In continued pursuit of water PCM HX development two full-scale, Orion sized water-based PCM HX's were constructed by Mezzo Technologies. These HX's were designed by applying prior research on freeze front propagation to a full-scale design. Design options considered included bladder restraint and clamping mechanisms, bladder manufacturing, tube patterns, fill/drain methods, manifold dimensions, weight optimization, and midplate designs. Two units, Units A and B, were constructed and differed only in their midplate design. Both units failed multiple times during testing. This report highlights learning outcomes from these tests and are applied to a final sub-scale PCM HX which is slated to be tested on the ISS in early 2017.

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

Mruetusatorn, Prachya; Boreyko, Jonathan B; Sarles, Stephen A

Droplet interface bilayers (DIBs) are a powerful platform for studying the dynamics of synthetic cellular membranes; however, very little has been done to exploit the unique dynamical features of DIBs. Here, we generate microscale droplet interface bilayers ( DIBs) by bringing together femtoliter-volume water droplets in a microfluidic oil channel, and characterize morphological changes of the DIBs as the droplets shrink due to evaporation. By varying the initial conditions of the system, we identify three distinct classes of dynamic morphology. (1) Buckling and Fission: When forming DIBs using the lipid-out method (lipids in oil phase), lipids in the shrinking monolayersmore » continually pair together and slide into the bilayer to conserve their mass. As the bilayer continues to grow, it becomes confined, buckles, and eventually fissions one or more vesicles. (2) Uniform Shrinking: When using the lipid-in method (lipids in water phase) to form DIBs, lipids uniformly transfer from the monolayers and bilayer into vesicles contained inside the water droplets. (3) Stretching and Unzipping: Finally, when the droplets are pinned to the wall(s) of the microfluidic channel, the droplets become stretched during evaporation, culminating in the unzipping of the bilayer and droplet separation. These findings offer a better understanding of the dynamics of coupled lipid interfaces.« less

Commencement Bay Studies Phase II, Environmental Impacts Assessment.

DTIC Science & Technology

1983-10-01

Approved for public release, distribution unlimited. 17. DISTRIBUTION STATEMENT (of the absirct entered In Block 20. If dlfforent from Report) IS...Matrix (Appendix D). 19. KEY WORDS (Continue n reveres side itnecsewy and identify by block number) Salmonids Wetlands Aesthetics City of Tacoma Marine...Water Quality Land and Water Use Port of Tacoma t AEINACr (Cm as ,.verem ebb N c evesey a - fdoswif by block n mbs) ames and Moore assessed the

The α-Effect and Competing Mechanisms: The Gas-Phase Reactions of Microsolvated Anions with Methyl Formate

NASA Astrophysics Data System (ADS)

Thomsen, Ditte L.; Nichols, Charles M.; Reece, Jennifer N.; Hammerum, Steen; Bierbaum, Veronica M.

2014-02-01

The enhanced reactivity of α-nucleophiles, which contain an electron lone pair adjacent to the reactive site, has been demonstrated in solution and in the gas phase and, recently, for the gas-phase SN2 reactions of the microsolvated HOO-(H2O) ion with methyl chloride. In the present work, we continue to explore the significance of microsolvation on the α-effect as we compare the gas-phase reactivity of the microsolvated α-nucleophile HOO-(H2O) with that of microsolvated normal alkoxy nucleophiles, RO-(H2O), in reactions with methyl formate, where three competing reactions are possible. The results reveal enhanced reactivity of HOO-(H2O) towards methyl formate, and clearly demonstrate the presence of an overall α-effect for the reactions of the microsolvated α-nucleophile. The association of the nucleophiles with a single water molecule significantly lowers the degree of proton abstraction and increases the SN2 and BAC2 reactivity compared with the unsolvated analogs. HOO-(H2O) reacts with methyl formate exclusively via the BAC2 channel. While microsolvation lowers the overall reaction efficiency, it enhances the BAC2 reaction efficiency for all anions compared with the unsolvated analogs. This may be explained by participation of the solvent water molecule in the BAC2 reaction in a way that continuously stabilizes the negative charge throughout the reaction.

Microwave assisted solid phase extraction for separation preconcentration sulfamethoxazole in wastewater using tyre based activated carbon as solid phase material prior to spectrophotometric determination

NASA Astrophysics Data System (ADS)

Mogolodi Dimpe, K.; Mpupa, Anele; Nomngongo, Philiswa N.

2018-01-01

This work was chiefly encouraged by the continuous consumption of antibiotics which eventually pose harmful effects on animals and human beings when present in water systems. In this study, the activated carbon (AC) was used as a solid phase material for the removal of sulfamethoxazole (SMX) in wastewater samples. The microwave assisted solid phase extraction (MASPE) as a sample extraction method was employed to better extract SMX in water samples and finally the analysis of SMX was done by the UV-Vis spectrophotometer. The microwave assisted solid phase extraction method was optimized using a two-level fractional factorial design by evaluating parameters such as pH, mass of adsorbent (MA), extraction time (ET), eluent ratio (ER) and microwave power (MP). Under optimized conditions, the limit of detection (LOD) and limit of quantification (LOQ) were 0.5 μg L- 1 and 1.7 μg L- 1, respectively, and intraday and interday precision expressed in terms of relative standard deviation were > 6%.The maximum adsorption capacity was 138 mg g- 1 for SMX and the adsorbent could be reused eight times. Lastly, the MASPE method was applied for the removal of SMX in wastewater samples collected from a domestic wastewater treatment plant (WWTP) and river water.

Water-in-oil Pickering emulsions stabilized by stearoylated microcrystalline cellulose.

PubMed

Pang, Bo; Liu, Huan; Liu, Peiwen; Peng, Xinwen; Zhang, Kai

2018-03-01

Hydrophobic particles with static water contact angles larger than 90° are more like to stabilize W/O Pickering emulsions. In particular, high internal phase Pickering emulsions (HIPEs) are of great interest for diverse applications. However, W/O HIPEs have rarely been realized using sustainable biopolymers. Herein, we used stearoylated microcrystalline cellulose (SMCC) to stabilize W/O Pickering emulsions and especially, W/O HIPEs. Moreover, these W/O HIPEs can be further used as platforms for the preparation of porous materials, such as porous foams. Stearoylated microcrystalline cellulose (SMCC) was prepared by modifying MCC with stearoyl chloride under heterogeneous conditions. Using SMCC as emulsifiers, W/O medium and high internal phase Pickering emulsions (MIPEs and HIPEs) with various organic solvents as continuous phases were prepared using one-step and two-step methods, respectively. Polystyrene (PS) foams were prepared after polymerization of oil phase using HIPEs as templates and their oil/water separation capacity were studied. SMCC could efficiently stabilize W/O Pickering emulsions and HIPEs could only be prepared via the two-step method. The internal phase volume fraction of the SMCC-stabilized HIPEs reached as high as 89%. Diverse internal phase volume fractions led to distinct inner structures of foams with closed or open cells. These macroporous polystyrene (PS) foams demonstrated great potential for the effective absorption of organic solvents from underwater. Copyright © 2017 Elsevier Inc. All rights reserved.

Stability conditions and mechanism of cream soaps: role of glycerol.

PubMed

Sagitani, Hiromichi

2014-01-01

Fatty acids, fatty acid potassium soaps, glycerol and water are essential ingredients in the production of stable cream soaps. In this study, the behavior of these components in solution was investigated to elucidate the stability conditions and mechanism of cream soaps. It was determined that the cream soaps were a dispersion of 1:1 acid soap (1:1 molar ratio of potassium soap/fatty acid) crystals in the lamellar gel phase, which has confirmed from the phase behavior diagrams and small angle X-ray scattering data. Glycerol was crucial ingredient in the formation of the lamellar gel phase. The cleansing process of the cream soaps was also evaluated using the same diagrams. The structure of the continuous phase in cream soaps changed from lamellar gel to a micellar aqueous solution upon the addition of water. This structural change during the washing process is important in producing the foaming activity of acid soaps to wash away dirt or excess fats from the skin surface.

CEBAF Superconducting Cavity RF Drive System

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

Fugitt, Jock; Moore, Thomas

1987-03-01

The CEBAR RF system consists of 418 individual RF amplifier chains. Each superconducting cavity is phase locked to the master drive reference line to within 1 degree, and the cavity field gradient is regulated to within 1 part in 10 by a state-of-the-art RF control module. Precision, continuously adjustable, modulo 360 phase shifters are used to generate the individual phase references, and a compensated RF detector is used for level feedback. The close coupled digital system enhances system accuracy, provides self-calibration, and continuously checks the system for malfunction. Calibration curves, the operating program, and system history are stored in anmore » on board EEPROM. The RF power is generated by a 5Kw, water cooled, permanent magnet focused klystorn. The klystons are clustered in groups of 8 and powered from a common supply. RF power is transmitted to the accelerator sections by semiflexible waveguide.« less

Hybrid composite based on poly(vinyl alcohol) and fillers from renewable resources

USDA-ARS?s Scientific Manuscript database

Hybrid composite laminates consisting of polyvinyl alcohol (PVA) as continuous phase (33% by weight) and lignocellulosic fillers, derived from sugarcane bagasse, apple and orange waste (22% by weight) were molded in a carver press in the presence of water and glycerol such as platicizers agents. Cor...

Gas-liquid-liquid three-phase flow pattern and pressure drop in a microfluidic chip: similarities with gas-liquid/liquid-liquid flows.

PubMed

Yue, Jun; Rebrov, Evgeny V; Schouten, Jaap C

2014-05-07

We report a three-phase slug flow and a parallel-slug flow as two major flow patterns found under the nitrogen-decane-water flow through a glass microfluidic chip which features a long microchannel with a hydraulic diameter of 98 μm connected to a cross-flow mixer. The three-phase slug flow pattern is characterized by a flow of decane droplets containing single elongated nitrogen bubbles, which are separated by water slugs. This flow pattern was observed at a superficial velocity of decane (in the range of about 0.6 to 10 mm s(-1)) typically lower than that of water for a given superficial gas velocity in the range of 30 to 91 mm s(-1). The parallel-slug flow pattern is characterized by a continuous water flow in one part of the channel cross section and a parallel flow of decane with dispersed nitrogen bubbles in the adjacent part of the channel cross section, which was observed at a superficial velocity of decane (in the range of about 2.5 to 40 mm s(-1)) typically higher than that of water for each given superficial gas velocity. The three-phase slug flow can be seen as a superimposition of both decane-water and nitrogen-decane slug flows observed in the chip when the flow of the third phase (viz. nitrogen or water, respectively) was set at zero. The parallel-slug flow can be seen as a superimposition of the decane-water parallel flow and the nitrogen-decane slug flow observed in the chip under the corresponding two-phase flow conditions. In case of small capillary numbers (Ca ≪ 0.1) and Weber numbers (We ≪ 1), the developed two-phase pressure drop model under a slug flow has been extended to obtain a three-phase slug flow model in which the 'nitrogen-in-decane' droplet is assumed as a pseudo-homogeneous droplet with an effective viscosity. The parallel flow and slug flow pressure drop models have been combined to obtain a parallel-slug flow model. The obtained models describe the experimental pressure drop with standard deviations of 8% and 12% for the three-phase slug flow and parallel-slug flow, respectively. An example is given to illustrate the model uses in designing bifurcated microchannels that split the three-phase slug flow for high-throughput processing.

A theoretical extension of the soil freezing curve paradigm

NASA Astrophysics Data System (ADS)

Amiri, Erfan A.; Craig, James R.; Kurylyk, Barret L.

2018-01-01

Numerical models of permafrost evolution in porous media typically rely upon a smooth continuous relation between pore ice saturation and sub-freezing temperature, rather than the abrupt phase change that occurs in pure media. Soil scientists have known for decades that this function, known as the soil freezing curve (SFC), is related to the soil water characteristic curve (SWCC) for unfrozen soils due to the analogous capillary and sorptive effects experienced during both soil freezing and drying. Herein we demonstrate that other factors beyond the SFC-SWCC relationship can influence the potential range over which pore water phase change occurs. In particular, we provide a theoretical extension for the functional form of the SFC based upon the presence of spatial heterogeneity in both soil thermal conductivity and the freezing point depression of water. We infer the functional form of the SFC from many abrupt-interface 1-D numerical simulations of heterogeneous systems with prescribed statistical distributions of water and soil properties. The proposed SFC paradigm extension has the appealing features that it (1) is determinable from measurable soil and water properties, (2) collapses into an abrupt phase transition for homogeneous media, (3) describes a wide range of heterogeneity within a single functional expression, and (4) replicates the observed hysteretic behavior of freeze-thaw cycles in soils.

Are superhydrophobic surfaces best for icephobicity?

PubMed

Jung, Stefan; Dorrestijn, Marko; Raps, Dominik; Das, Arindam; Megaridis, Constantine M; Poulikakos, Dimos

2011-03-15

Ice formation can have catastrophic consequences for human activity on the ground and in the air. Here we investigate water freezing delays on untreated and coated surfaces ranging from hydrophilic to superhydrophobic and use these delays to evaluate icephobicity. Supercooled water microdroplets are inkjet-deposited and coalesce until spontaneous freezing of the accumulated mass occurs. Surfaces with nanometer-scale roughness and higher wettability display unexpectedly long freezing delays, at least 1 order of magnitude longer than typical superhydrophobic surfaces with larger hierarchical roughness and low wettability. Directly related to the main focus on heterogeneous nucleation and freezing delay of supercooled water droplets, the observed ensuing crystallization process consisted of two distinct phases: one very rapid recalescent partial solidification phase and a subsequent slower phase. Observations of the droplet collision process employed for the continuous liquid mass accumulation up to the point of ice formation reveal a previously unseen atmospheric-pressure, subfreezing-temperature regime for liquid-on-liquid bounce. On the basis of the entropy reduction of water near a solid surface, we formulate a modification to the classical heterogeneous nucleation theory, which predicts the observed freezing delay trends. Our results bring to question recent emphasis on super water-repellent surface formulations for ice formation retardation and suggest that anti-icing design must optimize the competing influences of both wettability and roughness.

Buckling failure of square ice-nanotube arrays constrained in graphene nanocapillaries

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

Zhu, YinBo; Wang, FengChao, E-mail: wangfc@ustc.edu.cn; Wu, HengAn

Graphene confinement provides a new physical and mechanical environment with ultrahigh van der Waals pressure, resulting in new quasi-two-dimensional phases of few-layer ice. Polymorphic transition can occur in bilayer constrained water/ice system. Here, we perform a comprehensive study of the phase transition of AA-stacked bilayer water constrained within a graphene nanocapillary. The compression-limit and superheating-limit (phase) diagrams are obtained, based on the extensive molecular-dynamics simulations at numerous thermodynamic states. Liquid-to-solid, solid-to-solid, and solid-to-liquid-to-solid phase transitions are observed in the compression and superheating of bilayer water. Interestingly, there is a temperature threshold (∼275 K) in the compression-limit diagram, which indicates thatmore » the first-order and continuous-like phase transitions of bilayer water depend on the temperature. Two obviously different physical processes, compression and superheating, display similar structural evolution; that is, square ice-nanotube arrays (BL-VHDI) will bend first and then transform into bilayer triangular AA stacking ice (BL-AAI). The superheating limit of BL-VHDI exhibits local maxima, while that of BL-AAI increases monotonically. More importantly, from a mechanics point of view, we propose a novel mechanism of the transformation from BL-VHDI to BL-AAI, both for the compression and superheating limits. This structural transformation can be regarded as the “buckling failure” of the square-ice-nanotube columns, which is dominated by the lateral pressure.« less

Amelioration of chronic fluoride toxicity by calcium and fluoride-free water in rats.

PubMed

Shankar, Priyanka; Ghosh, Sudip; Bhaskarachary, K; Venkaiah, K; Khandare, Arjun L

2013-07-14

The study was undertaken to explore the amelioration of chronic fluoride (F) toxicity (with low and normal Ca) in rats. The study was conducted in two phases. In phase I (6 months), seventy-six Wistar, weanling male rats were assigned to four treatment groups: normal-Ca (0·5 %) diet (NCD), Ca+F - ; low-Ca (0·25 %) diet (LCD), Ca - F - ; NCD +100 parts per million (ppm) F water, Ca+F+; LCD +100 ppm F water, Ca - F+. In phase II (reversal experiment, 3 months), LCD was replaced with the NCD. Treatment groups Ca+F+ and Ca - F+ were divided into two subgroups to compare the effect of continuation v. discontinuation along with Ca supplementation on reversal of chronic F toxicity. In phase I, significantly reduced food efficiency ratio (FER), body weight gain (BWG), faecal F excretion, serum Ca and increased bone F deposition were observed in the treatment group Ca - F+. Reduced serum 25-hydroxy-vitamin D3, increased 1,25-dihydroxy-vitamin D3 and up-regulation of Ca-sensing receptor, vitamin D receptor and S100 Ca-binding protein G (S100G) were observed in treatment groups Ca - F - and Ca - F+. In phase II (reversal phase), FER, BWG and serum Ca in treatment groups Ca - F+/Ca+F - and Ca - F+/Ca+F+ were still lower, as compared with other groups. However, other variables were comparable. Down-regulation of S100G was observed in F-fed groups (Ca+F+/Ca+F+ and Ca - F+/Ca+F+) in phase II. It is concluded that low Ca aggravates F toxicity, which can be ameliorated after providing adequate Ca and F-free water. However, chronic F toxicity can interfere with Ca absorption by down-regulating S100G expression irrespective of Ca nutrition.

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

Nigro, Valentina, E-mail: nigro@fis.uniroma3.it; Bruni, Fabio; Ricci, Maria Antonietta

The temperature dependence of the local intra-particle structure of colloidal microgel particles, composed of interpenetrated polymer networks, has been investigated by small-angle neutron scattering at different pH and concentrations, in the range (299÷315) K, where a volume phase transition from a swollen to a shrunken state takes place. Data are well described by a theoretical model that takes into account the presence of both interpenetrated polymer networks and cross-linkers. Two different behaviors are found across the volume phase transition. At neutral pH and T ≈ 307 K, a sharp change of the local structure from a water rich open inhomogeneousmore » interpenetrated polymer network to a homogeneous porous solid-like structure after expelling water is observed. Differently, at acidic pH, the local structure changes almost continuously. These findings demonstrate that a fine control of the pH of the system allows to tune the sharpness of the volume-phase transition.« less

Rapid gas hydrate formation process

DOEpatents

Brown, Thomas D.; Taylor, Charles E.; Unione, Alfred J.

2013-01-15

The disclosure provides a method and apparatus for forming gas hydrates from a two-phase mixture of water and a hydrate forming gas. The two-phase mixture is created in a mixing zone which may be wholly included within the body of a spray nozzle. The two-phase mixture is subsequently sprayed into a reaction zone, where the reaction zone is under pressure and temperature conditions suitable for formation of the gas hydrate. The reaction zone pressure is less than the mixing zone pressure so that expansion of the hydrate-forming gas in the mixture provides a degree of cooling by the Joule-Thompson effect and provides more intimate mixing between the water and the hydrate-forming gas. The result of the process is the formation of gas hydrates continuously and with a greatly reduced induction time. An apparatus for conduct of the method is further provided.

A water bag theory of autoresonant Bernstein-Greene-Kruskal modes

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

Khain, P.; Friedland, L.

2007-08-15

The adiabatic water bag theory describing formation and passage through phase-space of driven, continuously phase-locked (autoresonant) coherent structures in plasmas [L. Friedland et al., Phys. Rev. Lett. 96, 225001 (2006)] and of the associated Bernstein-Greene-Kruskal (BGK) modes is developed. The phase-locking is achieved by using a chirped frequency ponderomotive drive, passing through kinetic Cerenkov-type resonances. The theory uses the adiabatic invariants (conserved actions of limiting trajectories) in the problem and, for a flat-top initial distribution of the electrons, reduces the calculation of the self-field of the driven BGK mode to solution of a few algebraic equations. The adiabatic multiwater bagmore » extension of the theory for applications to autoresonant BGK structures with more general initial distributions is suggested. The results of the theories are in very good agreement with numerical simulations.« less

Internal Dose from Food and Drink Ingestion in the Early Phase after the Accident

NASA Astrophysics Data System (ADS)

Kawai, Masaki; Yoshizawa, Nobuaki; Hirakawa, Sachiko; Murakami, Kana; Takizawa, Mari; Sato, Osamu; Takagi, Shunji; Miyatake, Hirokazu; Takahashi, Tomoyuki; Suzuki, Gen

2017-09-01

Activity concentrations in food and drink, represented by water and vegetables, have been monitored continuously since the Fukushima Daiichi Nuclear Power Plant accident, with a focus on radioactive cesium. On the other hand, iodine-131 was not measured systematically in the early phase after the accident. The activity concentrations of iodine-131 in food and drink are important to estimate internal exposure due to ingestion pathway. When the internal dose from ingestion in the evacuation areas is estimated, water is considered as the main ingestion pathway. In this study, we estimated the values of activity concentrations in water in the early phase after the accident, using a compartment model as an estimation method. The model uses measurement values of activity concentration and deposition rate of iodine-131 onto the ground, which is calculated from an atmospheric dispersion simulation. The model considers how drinking water would be affected by radionuclides deposited into water. We estimated the activity concentrations of water on Kawamata town and Minamisouma city during March of 2011 and the committed effective doses were 0.08 mSv and 0.06 mSv. We calculated the transfer parameters in the model for estimating the activity concentrations in the areas with a small amount of measurement data. In addition, we estimated the committed effective doses from vegetables using atmospheric dispersion simulation and FARMLAND model in case of eating certain vegetables as option information.

Mars surface-based factory: Computer control of a water treatment system to support a space colony on Mars

NASA Technical Reports Server (NTRS)

Brice, R.; Mosley, J.; Willis, D.; Coleman, K.; Martin, C.; Shelby, L.; Kelley, U.; Renfro, E.; Griffith, G.; Warsame, A.

1989-01-01

In a continued effort to design a surface-based factory on Mars for the production of oxygen and water, the Design Group at Prairie View A&M University made a preliminary study of the surface and atmospheric composition on Mars and determined the mass densities of the various gases in the martian atmosphere. Based on the initial studies, the design group determined oxygen and water to be the two products that could be produced economically under the martian conditions. Studies were also made on present production techniques to obtain water and oxygen. Analyses were made to evaluate the current methods of production that were adaptable to the martian conditions. The detailed report was contained in an Interim Report submitted to NASA/USRA in Aug. of 1986. Even though the initial effort was the production of oxygen and water, we found it necessary to produce some diluted gases that can be mixed with oxygen to constitute 'breathable' air. In Phase 2--Task 1A, the Prairie View A&M University team completed the conceptual design of a breathable-air manufacturing system, a means of drilling for underground water, and storage of water for future use. The design objective of the team for the 1987-1988 academic year was the conceptual design of an integrated system for the supply of quality water for biological consumption, farming, and residential and industrial use. The design has also been completed. Phase 2--Task 1C is the present task for the Prairie View Design Team. This is a continuation of the previous task, and the continuation of this effort is the investigation into the extraction of water from beneath the surface and an alternative method of extraction from ice formations on the surface of Mars if accessible. In addition to investigation of water extraction, a system for computer control of extraction and treatment was developed with emphasis on fully automated control with robotic repair and maintenance. It is expected that oxygen- and water-producing plants on Mars will be limited in the amount of human control that will be available to operate large and/or isolated plants. Therefore, it is imperative that computers be integrated into plant operation with the capability to maintain life support systems and analyze and replace defective parts or systems with no human interface.

Sampling trace organic compounds in water: a comparison of a continuous active sampler to continuous passive and discrete sampling methods

USGS Publications Warehouse

Coes, Alissa L.; Paretti, Nicholas V.; Foreman, William T.; Iverson, Jana L.; Alvarez, David A.

2014-01-01

A continuous active sampling method was compared to continuous passive and discrete sampling methods for the sampling of trace organic compounds (TOCs) in water. Results from each method are compared and contrasted in order to provide information for future investigators to use while selecting appropriate sampling methods for their research. The continuous low-level aquatic monitoring (CLAM) sampler (C.I.Agent® Storm-Water Solutions) is a submersible, low flow-rate sampler, that continuously draws water through solid-phase extraction media. CLAM samplers were deployed at two wastewater-dominated stream field sites in conjunction with the deployment of polar organic chemical integrative samplers (POCIS) and the collection of discrete (grab) water samples. All samples were analyzed for a suite of 69 TOCs. The CLAM and POCIS samples represent time-integrated samples that accumulate the TOCs present in the water over the deployment period (19–23 h for CLAM and 29 days for POCIS); the discrete samples represent only the TOCs present in the water at the time and place of sampling. Non-metric multi-dimensional scaling and cluster analysis were used to examine patterns in both TOC detections and relative concentrations between the three sampling methods. A greater number of TOCs were detected in the CLAM samples than in corresponding discrete and POCIS samples, but TOC concentrations in the CLAM samples were significantly lower than in the discrete and (or) POCIS samples. Thirteen TOCs of varying polarity were detected by all of the three methods. TOC detections and concentrations obtained by the three sampling methods, however, are dependent on multiple factors. This study found that stream discharge, constituent loading, and compound type all affected TOC concentrations detected by each method. In addition, TOC detections and concentrations were affected by the reporting limits, bias, recovery, and performance of each method.

Sampling trace organic compounds in water: a comparison of a continuous active sampler to continuous passive and discrete sampling methods.

PubMed

Coes, Alissa L; Paretti, Nicholas V; Foreman, William T; Iverson, Jana L; Alvarez, David A

2014-03-01

A continuous active sampling method was compared to continuous passive and discrete sampling methods for the sampling of trace organic compounds (TOCs) in water. Results from each method are compared and contrasted in order to provide information for future investigators to use while selecting appropriate sampling methods for their research. The continuous low-level aquatic monitoring (CLAM) sampler (C.I.Agent® Storm-Water Solutions) is a submersible, low flow-rate sampler, that continuously draws water through solid-phase extraction media. CLAM samplers were deployed at two wastewater-dominated stream field sites in conjunction with the deployment of polar organic chemical integrative samplers (POCIS) and the collection of discrete (grab) water samples. All samples were analyzed for a suite of 69 TOCs. The CLAM and POCIS samples represent time-integrated samples that accumulate the TOCs present in the water over the deployment period (19-23 h for CLAM and 29 days for POCIS); the discrete samples represent only the TOCs present in the water at the time and place of sampling. Non-metric multi-dimensional scaling and cluster analysis were used to examine patterns in both TOC detections and relative concentrations between the three sampling methods. A greater number of TOCs were detected in the CLAM samples than in corresponding discrete and POCIS samples, but TOC concentrations in the CLAM samples were significantly lower than in the discrete and (or) POCIS samples. Thirteen TOCs of varying polarity were detected by all of the three methods. TOC detections and concentrations obtained by the three sampling methods, however, are dependent on multiple factors. This study found that stream discharge, constituent loading, and compound type all affected TOC concentrations detected by each method. In addition, TOC detections and concentrations were affected by the reporting limits, bias, recovery, and performance of each method. Published by Elsevier B.V.

Transformation of a Water Slug in Free Fall Under the Conditions of Exposure to an Air Flow Orthogonal to the Direction of the Slug Motion

NASA Astrophysics Data System (ADS)

Volkov, R. S.; Zabelin, M. V.; Kuznetsov, G. V.; Strizhak, P. A.

2016-07-01

An experimental study has been made of the influence of an orthogonal (side) air flow propagating with a velocity to 5 m/s on the phases of transformation of a water slug with an initial volume of 0.05-0.5 liter in free fall from a height of 3 m. Use was made of Phantom V411 and Phantom Miro M310 high-speed video cameras and a Tema Automotive software system with the function of continuous tracking. The laws of retardation of the phases of transformation of the water slug from the instant of formation to that of formation of a droplet cloud under the action of the air flow orthogonal to the direction of the slug motion, and also of the deceleration, removal, and destruction of the droplets and fragments of water separating from the slug surface, have been established.

Effect of intermittent aeration strategies on treatment performance and microbial community of an IFAS reactor treating municipal waste water.

PubMed

Singh, Nitin Kumar; Bhatia, Akansha; Kazmi, Absar Ahmad

2017-11-01

This study investigated the effect of various intermittent aeration (IA) cycles on organics and nutrient removal, and microbial communities in an integrated fixed-film activated sludge (IFAS) reactor treating municipal waste water. Average effluent biological oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids, total nitrogen (TN) and total phosphorus (TP) values were noted as 20, 50, 30, 12 and 1.5 mgL -1 , respectively, in continuous aeration mode. A total of four operational conditions (run 1, continuous aeration; run 2, 150/30 min aeration on/off time; run 3, 120/60 min aeration on/off time and run 4, 90/60 min aeration on/off time) were investigated in IFAS reactor assessment. Among the all examined IA cycles, IA phase 2 gave the maximum COD and BOD removals with values recorded as 97% and 93.8%, respectively. With respect to nutrient removal (TN and TP), IA phase 1 was found to be optimum. Pathogen removal efficiency of present system was recorded as 90-95% during the three phases. With regard to settling characteristics, pilot showed poor settling during IA schedules, which was also evidenced by high sludge volume index values. Overall, IA could be used as a feasible way to improve the overall performance of IFAS system.

Determining Cloud Thermodynamic Phase from Micropulse Lidar Network Data

NASA Technical Reports Server (NTRS)

Lewis, Jasper R.; Campbell, James; Lolli, Simone; Tan, Ivy; Welton, Ellsworth J.

2017-01-01

Determining cloud thermodynamic phase is a critical factor in studies of Earth's radiation budget. Here we use observations from the NASA Micro Pulse Lidar Network (MPLNET) and thermodynamic profiles from the Goddard Earth Observing System, version 5 (GEOS-5) to distinguish liquid water, mixed-phase, and ice water clouds. The MPLNET provides sparse global, autonomous, and continuous measurements of clouds and aerosols which have been used in a number of scientific investigations to date. The use of a standardized instrument and a common suite of data processing algorithms with thorough uncertainty characterization allows for straightforward comparisons between sites. Lidars with polarization capabilities have recently been incorporated into the MPLNET project which allows, for the first time, the ability to infer a cloud thermodynamic phase. This presentation will look specifically at the occurrence of ice and mixed phase clouds in the temperature region of -10 C to -40 C for different climatological regions and seasons. We compare MPLNET occurrences of mixed-phase clouds to an historical climatology based on observations from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument aboard the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) spacecraft.

Determining cloud thermodynamic phase from Micropulse Lidar Network data

NASA Astrophysics Data System (ADS)

Lewis, J. R.; Campbell, J. R.; Lolli, S.; Tan, I.; Welton, E. J.

2017-12-01

Determining cloud thermodynamic phase is a critical factor in studies of Earth's radiation budget. Here we use observations from the NASA Micropulse Lidar Network (MPLNET) and thermodynamic profiles from the Goddard Earth Observing System, version 5 (GEOS-5) to distinguish liquid water, mixed-phase, and ice water clouds. The MPLNET provides sparse global, autonomous, and continuous measurements of clouds and aerosols which have been used in a number of scientific investigations to date. The use of a standardized instrument and a common suite of data processing algorithms with thorough uncertainty characterization allows for straightforward comparisons between sites. Lidars with polarization capabilities have recently been incorporated into the MPLNET project which allows, for the first time, the ability to infer a cloud thermodynamic phase. This presentation will look specifically at the occurrence of ice and mixed phase clouds in the temperature region of 0 °C to -40 °C for different climatological regions and seasons. We compare MPLNET occurrences of mixed-phase clouds to an historical climatology based on observations from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument aboard the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) spacecraft.

Optimising mobile phase composition, its flow-rate and column temperature in HPLC using taboo search.

PubMed

Guillaume, Y C; Peyrin, E

2000-03-06

A chemometric methodology is proposed to study the separation of seven p-hydroxybenzoic esters in reversed phase liquid chromatography (RPLC). Fifteen experiments were found to be necessary to find a mathematical model which linked a novel chromatographic response function (CRF) with the column temperature, the water fraction in the mobile phase and its flow rate. The CRF optimum was determined using a new algorithm based on Glover's taboo search (TS). A flow-rate of 0.9 ml min(-1) with a water fraction of 0.64 in the ACN-water mixture and a column temperature of 10 degrees C gave the most efficient separation conditions. The usefulness of TS was compared with the pure random search (PRS) and simplex search (SS). As demonstrated by calculations, the algorithm avoids entrapment in local minima and continues the search to give a near-optimal final solution. Unlike other methods of global optimisation, this procedure is generally applicable, easy to implement, derivative free, conceptually simple and could be used in the future for much more complex optimisation problems.

Pickering emulsions stabilized by paraffin wax and Laponite clay particles.

PubMed

Li, Caifu; Liu, Qian; Mei, Zhen; Wang, Jun; Xu, Jian; Sun, Dejun

2009-08-01

Emulsions containing wax in dispersed droplets stabilized by disc-like Laponite clay particles are prepared. Properties of the emulsions prepared at different temperatures are examined using stability, microscopy and droplet-size analysis. At low temperature, the wax crystals in the oil droplets can protrude through the interface, leading to droplet coalescence. But at higher temperatures, the droplet size decreases with wax concentration. Considering the viscosity of the oil phase and the interfacial tension, we conclude that the wax is liquid-like during the high temperature emulsification process, but during cooling wax crystals appear around the oil/water interface and stabilize the droplets. The oil/water ratio has minimal effect on the emulsions between ratios of 3:7 and 7:3. The Laponite is believed to stabilize the emulsions by increasing the viscosity of the continuous phase and also by adsorbing at the oil/water interface, thus providing a physical barrier to coalescence.

Cellulose nanofibrils for one-step stabilization of multiple emulsions (W/O/W) based on soybean oil.

PubMed

Carrillo, Carlos A; Nypelö, Tiina E; Rojas, Orlando J

2015-05-01

Cellulose nanofibrils (CNF) were incorporated in water-in-oil (W/O) microemulsions and emulsions, as well as water-in-oil-in-water (W/O/W) multiple emulsions using soybean oil. The addition of CNF to the aqueous phase expanded the composition range to obtain W/O/W emulsions. CNF also increased the viscosity of the continuous phase and reduced the drop size both of which increased the stability and effective viscosity of the emulsions. The effects of oil type and polarity on the properties of the W/O/W emulsions were tested with limonene and octane, which compared to soybean oil produced a smaller emulsion drop size, and thus a higher emulsion viscosity. Overall, CNF are a feasible alternative to conventional polysaccharides as stability enhancers for normal and multiple emulsions that exhibit strong shear thinning behavior. Copyright © 2014 Elsevier Inc. All rights reserved.

Performance evaluation of SPE electrolyzer for Space Station life support

NASA Technical Reports Server (NTRS)

Erickson, A. C.; Puskar, M. C.; Zagaja, J. A.; Miller, P. S.

1987-01-01

An static water-vapor feed electrolyzer has been developed as a candidate for Space Station life-support oxygen generation. The five-cell electrolysis module has eliminated the need for phase separation devices, pumps, and deionizers by transporting only water vapor to the solid polymer electrolyte cells. The introduction of an innovative electrochemical hydrogen pump allows the use of low-pressure reclaimed water to generate gas pressures of up to 230 psia. The electrolyzer has been tested in a computer-controlled test stand featuring continuous, cyclic, and standby operation (including automatic shutdown with fault detection).

Microfluidic Droplet Dehydration for Concentrating Processes in Biomolecules

NASA Astrophysics Data System (ADS)

Anna, Shelley

2014-03-01

Droplets in microfluidic devices have proven useful as picoliter reactors for biochemical processing operations such as polymerase chain reaction, protein crystallization, and the study of enzyme kinetics. Although droplets are typically considered to be self-contained, constant volume reactors, there can be significant transport between the dispersed and continuous phases depending on solubility and other factors. In the present talk, we show that water droplets trapped within a microfluidic device for tens of hours slowly dehydrate, concentrating the contents encapsulated within. We use this slow dehydration along with control of the initial droplet composition to influence gellation, crystallization, and phase separation processes. By examining these concentrating processes in many trapped drops at once we gain insight into the stochastic nature of the events. In one example, we show that dehydration rate impacts the probability of forming a specific crystal habit in a crystallizing amino acid. In another example, we phase separate a common aqueous two-phase system within droplets and use the ensuing two phases to separate DNA from an initial mixture. We further influence wetting conditions between the two aqueous polymer phases and the continuous oil, promoting complete de-wetting and physical separation of the polymer phases. Thus, controlled dehydration of droplets allows for concentration, separation, and purification of important biomolecules on a chip.

[Synthesis of hollow titania microspheres by using microfluidic droplet-template].

PubMed

Ma, Jingyun; Jiang, Lei; Qin, Jianhu

2011-09-01

Droplet-based microfluidics is of great interest due to its particular characteristics compared with the conventional methods, such as reduced reagent consumption, rapid mixing, high-throughput, shape controlled, etc. A novel method using microfluidic droplet as soft template for the synthesis of hollow titania microspheres was developed. A typical polydimethylsiloxane (PDMS) microfluidic device containing "flow-focusing" geometry was used to generate water/oil (W/O) droplet. The mechanism for the hollow structure formation was based on the interfacial hydrolysis reaction between the continuous phase containing titanium butoxide precursor and the dispersed containing water. The continuous phase mixed with butanol was added in the downstream of the channel after the hydrolysis reaction. This step was used for drawing the water out of the microgels for further hydrolysis. The microgels obtained through a glass pipe integrated were washed, dried under vacuum and calcined after aging for a certain time. The fluorescence and scanning electron microscope (SEM) image of the microspheres indicated the hollow structure and the thickness of the shell. In addition, these microspheres with thin shell (about 2 microm) were apt to rupture and collapse. Droplet-based microfluidic offered a gentle and size-controllable manner to moderate this problem. Moreover, it has potential applications in photocatalysis combined with some modification realized on the chip simultaneously.

Vasopressin Receptor Signaling and Cycling of Water Channels in Renal Epithelia.

DTIC Science & Technology

1994-08-31

bladder (Bentley, 1958; DiBona et al., 1969; Hays, 1983; Mia et al., 1983, 1987, 1991a and others). ADH stimulates water reabsorption in this tissue...out of a continuous phase of microridges (Davis et al., 1974; DiBona , 1978, 1981; Dratwa et al., 1979; Mills and Malick, 1978; Mia et al., 1983, 1988a...be directed by dynamic actions of the microtubules and microfilaments (Hays et al., 1982; Taylor et al., 1973; Hardy and DiBona , 1982; Pearl and Taylor

Performance comparison between packet and continuous data transmission using two adaptive equalizers in shallow water

NASA Astrophysics Data System (ADS)

Yoon, Jong Rak; Park, Kyu-Chil; Park, Jihyun

2015-07-01

Transmitted signals are markedly affected by sea surface and bottom boundaries in shallow water. The time variant reflection signals from such boundaries characterize the channel as a frequency-selective fading channel and cause intersymbol interference (ISI) in underwater acoustic communication. A channel-estimate-based equalizer is usually adopted to compensate for the reflected signals under this kind of acoustic channel. In this study, we apply two approaches for packet and continuous data transmission of the quadrature phase shift keying (QPSK) system. One is the use of a two-dimensional (2D) rotation matrix in a non-frequency-selective channel. The other is the use of two equalizers of types — the feed forward equalizer (FFE) and decision-directed equalizer (DDE) — with a normalized least mean square (NLMS) algorithm in a frequency-selective channel. The percentage improvement of packet transmission is notably better than that of continuous transmission.

Measurement Of Multiphase Flow Water Fraction And Water-cut

NASA Astrophysics Data System (ADS)

Xie, Cheng-gang

2007-06-01

This paper describes a microwave transmission multiphase flow water-cut meter that measures the amplitude attenuation and phase shift across a pipe diameter at multiple frequencies using cavity-backed antennas. The multiphase flow mixture permittivity and conductivity are derived from a unified microwave transmission model for both water- and oil-continuous flows over a wide water-conductivity range; this is far beyond the capability of microwave-resonance-based sensors currently on the market. The water fraction and water cut are derived from a three-component gas-oil-water mixing model using the mixture permittivity or the mixture conductivity and an independently measured mixture density. Water salinity variations caused, for example, by changing formation water or formation/injection water breakthrough can be detected and corrected using an online water-conductivity tracking technique based on the interpretation of the mixture permittivity and conductivity, simultaneously measured by a single-modality microwave sensor.

The influence of the surface composition of mixed monolayer films on the evaporation coefficient of water.

PubMed

Miles, Rachael E H; Davies, James F; Reid, Jonathan P

2016-07-20

We explore the dependence of the evaporation coefficient of water from aqueous droplets on the composition of a surface film, considering in particular the influence of monolayer mixed component films on the evaporative mass flux. Measurements with binary component films formed from long chain alcohols, specifically tridecanol (C13H27OH) and pentadecanol (C15H31OH), and tetradecanol (C14H29OH) and hexadecanol (C16H33OH), show that the evaporation coefficient is dependent on the mole fractions of the two components forming the monolayer film. Immediately at the point of film formation and commensurate reduction in droplet evaporation rate, the evaporation coefficient is equal to a mole fraction weighted average of the evaporation coefficients through the equivalent single component films. As a droplet continues to diminish in surface area with continued loss of water, the more-soluble, shorter alkyl chain component preferentially partitions into the droplet bulk with the evaporation coefficient tending towards that through a single component film formed simply from the less-soluble, longer chain alcohol. We also show that the addition of a long chain alcohol to an aqueous-sucrose droplet can facilitate control over the degree of dehydration achieved during evaporation. After undergoing rapid gas-phase diffusion limited water evaporation, binary aqueous-sucrose droplets show a continued slow evaporative flux that is limited by slow diffusional mass transport within the particle bulk due to the rapidly increasing particle viscosity and strong concentration gradients that are established. The addition of a long chain alcohol to the droplet is shown to slow the initial rate of water loss, leading to a droplet composition that remains more homogeneous for a longer period of time. When the sucrose concentration has achieved a sufficiently high value, and the diffusion constant of water has decreased accordingly so that bulk phase diffusion arrest occurs in the monolayer coated particle, the droplet is found to have lost a greater proportion of its initial water content. A greater degree of slowing in the evaporative flux can be achieved by increasing the chain length of the surface active alcohol, leading to a greater degree of dehydration.

Microwave assisted solid phase extraction for separation preconcentration sulfamethoxazole in wastewater using tyre based activated carbon as solid phase material prior to spectrophotometric determination.

PubMed

Mogolodi Dimpe, K; Mpupa, Anele; Nomngongo, Philiswa N

2018-01-05

This work was chiefly encouraged by the continuous consumption of antibiotics which eventually pose harmful effects on animals and human beings when present in water systems. In this study, the activated carbon (AC) was used as a solid phase material for the removal of sulfamethoxazole (SMX) in wastewater samples. The microwave assisted solid phase extraction (MASPE) as a sample extraction method was employed to better extract SMX in water samples and finally the analysis of SMX was done by the UV-Vis spectrophotometer. The microwave assisted solid phase extraction method was optimized using a two-level fractional factorial design by evaluating parameters such as pH, mass of adsorbent (MA), extraction time (ET), eluent ratio (ER) and microwave power (MP). Under optimized conditions, the limit of detection (LOD) and limit of quantification (LOQ) were 0.5μgL -1 and 1.7μgL -1 , respectively, and intraday and interday precision expressed in terms of relative standard deviation were >6%.The maximum adsorption capacity was 138mgg -1 for SMX and the adsorbent could be reused eight times. Lastly, the MASPE method was applied for the removal of SMX in wastewater samples collected from a domestic wastewater treatment plant (WWTP) and river water. Copyright © 2017 Elsevier B.V. All rights reserved.

Viking Phase III

NASA Technical Reports Server (NTRS)

1978-01-01

VIKING PHASE III - With the incredible success of the Viking missions on Mars, mission operations have progressed though a series of phases - each being funded as mission success dictated its potential. The Viking Primary Mission phase was concluded in November, 1976, when the reins were passed on to the second phase - the Viking Extended Mission. The Extended Mission successfully carried spacecraft operations through the desired period of time needed to provided a profile of a full Martian year, but would have fallen a little short of connecting and overlapping a full Martian year of Viking operations which scientists desired as a means of determining the degree of duplicity in the red planet's seasons - at least for the summer period. Without this continuation of spacecraft data acquisitions to and beyond the seasonal points when the spacecraft actually began their Mars observations, there would be no way of knowing whether the changing environmental values - such as temperatures and winds atmospheric dynamics and water vapor, surface thermal dynamics, etc. - would match up with those acquired as the spacecraft began investigations during the summer and fall of 1976. This same broad interest can be specifically pursued at the surface - where hundreds of rocks, soil drifts and other features have become extremely familiar during long-term analysis. This picture was acquired on the 690th Martian day of Lander 1 operations - 4009th picture sequence commanded of the two Viking Landers. As such, it became the first picture acquired as the third phase of Viking operations got under way - the Viking Continuation Mission. Between the start of the Continuation Mission in April, 1978, until spacecraft operations are concluded in November, the landers will acquire an additional 200 pictures. These will be used to monitor the two landscaped for the surface changes. All four cameras, two on Lander 1 and two on Lander 2, continue to operate perfectly. Both landers will also continue to monitor weather conditions - recording atmospheric pressure and its variations, daily temperature extremes, and wind behavior at the two lander locations.

[Study on phase correction method of spatial heterodyne spectrometer].

PubMed

Wang, Xin-Qiang; Ye, Song; Zhang, Li-Juan; Xiong, Wei

2013-05-01

Phase distortion exists in collected interferogram because of a variety of measure reasons when spatial heterodyne spectrometers are used in practice. So an improved phase correction method is presented. The phase curve of interferogram was obtained through Fourier inverse transform to extract single side transform spectrum, based on which, the phase distortions were attained by fitting phase slope, so were the phase correction functions, and the convolution was processed between transform spectrum and phase correction function to implement spectrum phase correction. The method was applied to phase correction of actually measured monochromatic spectrum and emulational water vapor spectrum. Experimental results show that the low-frequency false signals in monochromatic spectrum fringe would be eliminated effectively to increase the periodicity and the symmetry of interferogram, in addition when the continuous spectrum imposed phase error was corrected, the standard deviation between it and the original spectrum would be reduced form 0.47 to 0.20, and thus the accuracy of spectrum could be improved.

Kinetics of the water/air phase transition of radon and its implication on detection of radon-in-water concentrations: practical assessment of different on-site radon extraction methods.

PubMed

Schubert, Michael; Paschke, Albrecht; Bednorz, Denise; Bürkin, Walter; Stieglitz, Thomas

2012-08-21

The on-site measurement of radon-in-water concentrations relies on extraction of radon from the water followed by its detection by means of a mobile radon-in-air monitor. Many applications of radon as a naturally occurring aquatic tracer require the collection of continuous radon concentration time series, thus necessitating the continuous extraction of radon either from a permanent water stream supplied by a water pump or directly from a water body or a groundwater monitoring well. Essentially, three different types of extraction units are available for this purpose: (i) a flow-through spray chamber, (ii) a flow-through membrane extraction module, and (iii) a submersible (usually coiled) membrane tube. In this paper we discuss the advantages and disadvantages of these three methodical approaches with particular focus on their individual response to instantaneously changing radon-in-water concentrations. After a concise introduction into theoretical aspects of water/air phase transition kinetics of radon, experimental results for the three types of extraction units are presented. Quantitative suggestions for optimizing the detection setup by increasing the water/air interface and by reducing the air volume circulating through the degassing unit and radon detector are made. It was shown that the flow-through spray chamber and flow-through membrane perform nearly similarly, whereas the submersible membrane tubing has a significantly larger delay in response to concentration changes. The flow-through spray chamber is most suitable in turbid waters and to applications where high flow rates of the water pump stream can be achieved (e.g., where the power supply is not constrained by field conditions). The flow-through membrane is most suited to radon extraction from clear water and in field conditions where the power supply to a water pump is limited, e.g., from batteries. Finally, the submersible membrane tube is most suitable if radon is to be extracted in situ without any water pumping, e.g., in groundwater wells with a low yield, or in long-term time series, in which short-term variations in the radon concentration are of no relevance.

Water: A Tale of Two Liquids.

PubMed

Gallo, Paola; Amann-Winkel, Katrin; Angell, Charles Austen; Anisimov, Mikhail Alexeevich; Caupin, Frédéric; Chakravarty, Charusita; Lascaris, Erik; Loerting, Thomas; Panagiotopoulos, Athanassios Zois; Russo, John; Sellberg, Jonas Alexander; Stanley, Harry Eugene; Tanaka, Hajime; Vega, Carlos; Xu, Limei; Pettersson, Lars Gunnar Moody

2016-07-13

Water is the most abundant liquid on earth and also the substance with the largest number of anomalies in its properties. It is a prerequisite for life and as such a most important subject of current research in chemical physics and physical chemistry. In spite of its simplicity as a liquid, it has an enormously rich phase diagram where different types of ices, amorphous phases, and anomalies disclose a path that points to unique thermodynamics of its supercooled liquid state that still hides many unraveled secrets. In this review we describe the behavior of water in the regime from ambient conditions to the deeply supercooled region. The review describes simulations and experiments on this anomalous liquid. Several scenarios have been proposed to explain the anomalous properties that become strongly enhanced in the supercooled region. Among those, the second critical-point scenario has been investigated extensively, and at present most experimental evidence point to this scenario. Starting from very low temperatures, a coexistence line between a high-density amorphous phase and a low-density amorphous phase would continue in a coexistence line between a high-density and a low-density liquid phase terminating in a liquid-liquid critical point, LLCP. On approaching this LLCP from the one-phase region, a crossover in thermodynamics and dynamics can be found. This is discussed based on a picture of a temperature-dependent balance between a high-density liquid and a low-density liquid favored by, respectively, entropy and enthalpy, leading to a consistent picture of the thermodynamics of bulk water. Ice nucleation is also discussed, since this is what severely impedes experimental investigation of the vicinity of the proposed LLCP. Experimental investigation of stretched water, i.e., water at negative pressure, gives access to a different regime of the complex water diagram. Different ways to inhibit crystallization through confinement and aqueous solutions are discussed through results from experiments and simulations using the most sophisticated and advanced techniques. These findings represent tiles of a global picture that still needs to be completed. Some of the possible experimental lines of research that are essential to complete this picture are explored.

Water: A Tale of Two Liquids

DOE PAGES

Gallo, Paola; Amann-Winkel, Katrin; Angell, Charles Austen; ...

2016-07-05

Water is the most abundant liquid on earth and also the substance with the largest number of anomalies in its properties. It is a prerequisite for life and as such a most important subject of current research in chemical physics and physical chemistry. In spite of its simplicity as a liquid, it has an enormously rich phase diagram where different types of ices, amorphous phases, and anomalies disclose a path that points to unique thermodynamics of its supercooled liquid state that still hides many unraveled secrets. In this review we describe the behavior of water in the regime from ambientmore » conditions to the deeply supercooled region. The review describes simulations and experiments on this anomalous liquid. Several scenarios have been proposed to explain the anomalous properties that become strongly enhanced in the supercooled region. Among those, the second critical-point scenario has been investigated extensively, and at present most experimental evidence point to this scenario. Starting from very low temperatures, a coexistence line between a high-density amorphous phase and a low-density amorphous phase would continue in a coexistence line between a high-density and a low-density liquid phase terminating in a liquid–liquid critical point, LLCP. On approaching this LLCP from the one-phase region, a crossover in thermodynamics and dynamics can be found. This is discussed based on a picture of a temperature-dependent balance between a high-density liquid and a low-density liquid favored by, respectively, entropy and enthalpy, leading to a consistent picture of the thermodynamics of bulk water. Ice nucleation is also discussed, since this is what severely impedes experimental investigation of the vicinity of the proposed LLCP. Experimental investigation of stretched water, i.e., water at negative pressure, gives access to a different regime of the complex water diagram. Different ways to inhibit crystallization through confinement and aqueous solutions are discussed through results from experiments and simulations using the most sophisticated and advanced techniques. These findings represent tiles of a global picture that still needs to be completed. In conclusion, some of the possible experimental lines of research that are essential to complete this picture are explored.« less

Water: A Tale of Two Liquids

PubMed Central

2016-01-01

Water is the most abundant liquid on earth and also the substance with the largest number of anomalies in its properties. It is a prerequisite for life and as such a most important subject of current research in chemical physics and physical chemistry. In spite of its simplicity as a liquid, it has an enormously rich phase diagram where different types of ices, amorphous phases, and anomalies disclose a path that points to unique thermodynamics of its supercooled liquid state that still hides many unraveled secrets. In this review we describe the behavior of water in the regime from ambient conditions to the deeply supercooled region. The review describes simulations and experiments on this anomalous liquid. Several scenarios have been proposed to explain the anomalous properties that become strongly enhanced in the supercooled region. Among those, the second critical-point scenario has been investigated extensively, and at present most experimental evidence point to this scenario. Starting from very low temperatures, a coexistence line between a high-density amorphous phase and a low-density amorphous phase would continue in a coexistence line between a high-density and a low-density liquid phase terminating in a liquid–liquid critical point, LLCP. On approaching this LLCP from the one-phase region, a crossover in thermodynamics and dynamics can be found. This is discussed based on a picture of a temperature-dependent balance between a high-density liquid and a low-density liquid favored by, respectively, entropy and enthalpy, leading to a consistent picture of the thermodynamics of bulk water. Ice nucleation is also discussed, since this is what severely impedes experimental investigation of the vicinity of the proposed LLCP. Experimental investigation of stretched water, i.e., water at negative pressure, gives access to a different regime of the complex water diagram. Different ways to inhibit crystallization through confinement and aqueous solutions are discussed through results from experiments and simulations using the most sophisticated and advanced techniques. These findings represent tiles of a global picture that still needs to be completed. Some of the possible experimental lines of research that are essential to complete this picture are explored. PMID:27380438

[Geo-spectrum characteristics of land use change in Jiangsu Province, China.

PubMed

Lyu, Xiao; Shi, Yang Yang; Huang, Xian Jin; Sun, Xiao Fang; Miao, Zhi Wei

2016-04-22

This paper studied the spatial-temporal characteristics and rules of land use change in Jiangsu Province using theories and methods of geo-spectrum. Based on the land use data translated from remote sensing images of 1990, 2000 and 2010, we synthesized the geo-spectrum of the mode of arable land use change and that of land use change in two corresponding phases, 1990-2000 and 2000-2010, in Jiangsu using ArcGIS 10.0. The results showed that in the phase of 1990-2000, the major characteristics of land use change were swaps between the geo-spectrum unit of arable land and urban-rural construction land, arable land and water body, and arable land and grassland. Specifically, the patterns of "arable land → urban-rural construction land" and "arable land→ water body" were highly significant. We also found the reduction of arable land area and the concentration of its spatial distribution. In the phase of 2000-2010, the "arable land → urban-rural construction land" pattern was still the most salient characteristic. In addition, the patterns of "grassland → water body" and "urban-rural construction land → water body" became more spatially concentrated and tended to expand. Compared with the previous phase, the area of the land use in the phase of 2000-2010 had been changed expanded and became more scattered. Overall, the geo-spectrum of arable land use change in Jiangsu was mainly shaped by the anaphase change type and partially by the prophase change type, with a tiny influence of the repeated and continuous change.

Microrheology and microstructure of water-in-water emulsions containing sodium caseinate and locust bean gum.

PubMed

Moschakis, Thomas; Chantzos, Nikos; Biliaderis, Costas G; Dickinson, Eric

2018-05-23

The mechanical response on the microscale of phase-separated water-in-water emulsions containing sodium caseinate (SCN) and locust bean gum (LBG) has been monitored by confocal laser scanning microscopy and particle tracking microrheology. Mixed biopolymer systems exhibiting phase-separated micro-regions were enriched in either protein or polysaccharide in the continuous or dispersed phase, depending on the weight ratio of the two biopolymers. Measurements of the tracking of charged probe particles revealed that the local rheological properties of protein-rich regions were considerably lower than that of LBG-rich domains for all the biopolymer ratios examined. At pH 7 in the absence of added salt, the viscosity of the protein-rich regions was little affected by an increase in overall LBG concentration, which is consistent with the phase separation mechanism in the mixed solution of charged (SCN) and uncharged (LBG) biopolymers being dominated by the relative entropy of the counter-ions associated with the charged protein molecules. Addition of salt was found to produce an enhancement in the level of thermodynamic incompatibility, leading to faster and more pronounced phase separation, and altering the micro-viscosity of protein-rich regions. At high ionic strength, it was also noted that there was a pronounced accumulation of incorporated probe particles at the liquid-liquid interface. The microrheological properties of the SCN-rich regions were found to be substantially pH-dependent in the range 7 > pH > 5.4. By adjusting the acidification conditions and the biopolymer ratio, discrete protein-based microspheres were generated with potential applications as a functional food ingredient.

Hydrogeological conceptual model determined from baseline and construction phase groundwater pressure and surface tilt-meter data at the Mizunami underground research laboratory, Japan

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

Takeuchi, Shinji; Takeuchi, Ryuji; Salden, Walter

2007-07-01

A hydrogeological conceptual model has been developed based on pressure responses observed at multilevel pressure monitoring zones in seven boreholes and surface tilt data in and around the Mizunami Underground Research Laboratory site. Pressure changes caused by some earthquakes, cross-hole hydraulic testing, and shaft excavation activities are considered. Surface tilt has been measured from the half way of the shaft excavation phase. The shaft excavation has been commenced from July 2003 with two shafts (Main shaft and Ventilation shaft). By the end of October 2005, discharging of water in the shafts has been halted at the depths of 172 mmore » and 191 m respectively to allow modifications to be made to the water treatment facility due to an excess of F and B concentration in the water. This results in the recovery of the groundwater levels and filling of the underground workings. Beginning in February 2006 pumping has been resumed and the underground workings have been re-occupied. Continuous groundwater pressure and surface tilt measurements with some numerical analysis during the shaft excavation phase show the existence of the flow barrier fault predicted from the surface-based investigation phase and hydraulic parameter around the shafts. (authors)« less

Phase Change Material Trade Study: A Comparison Between Wax and Water for Manned Spacecraft

NASA Technical Reports Server (NTRS)

Quinn, Gregory; Hodgson, Ed; Stephan, Ryan A,

2011-01-01

Phase change material heat sinks have been recognized as an important tool in optimizing thermal control systems for space exploration vehicles and habitats that must deal with widely varying thermal loads and environments. In order to better focus technology investment in this arena, NASA has supported a trade study with the objective of identifying where the best potential pay-off can be found among identified aqueous and paraffin wax phase change materials and phase change material heat sink design approaches. The study used a representative exploration mission with well understood parameters to support the trade. Additional sensitivity studies were performed to ensure the applicability of study results across varying systems and destinations. Results from the study indicate that replacing a wax PCM heat sink with a water ice PCM heat sink has the potential to decrease the equivalent system mass of the mission s vehicle through a combination of a smaller heat sink and a slight 5% increase in radiator size or the addition of a lightweight heat pump. An evaluation of existing and emerging PCM heat sink technologies indicates that further mass savings should be achievable through continued development of those technologies. The largest mass savings may be realized by eliminating the melting and freezing pressure of wax and water, respectively.

Study of axial mixing, holdup and slip velocity of dispersed phase in a pulsed sieve plate extraction column using radiotracer technique.

PubMed

Ghiyas Ud Din; Imran Rafiq Chughtai; Hameed Inayat, Mansoor; Hussain Khan, Iqbal

2009-01-01

Axial mixing, holdup and slip velocity of dispersed phase which are parameters of fundamental importance in the design and operation of liquid-liquid extraction pulsed sieve plate columns have been investigated. Experiments for residence time distribution (RTD) analysis have been carried out for a range of pulsation frequency and amplitude in a liquid-liquid extraction pulsed sieve plate column with water as dispersed and kerosene as continuous phase using radiotracer technique. The column was operated in emulsion region and (99m)Tc in the form of sodium pertechnetate eluted from a (99)Mo/(99m)Tc generator was used to trace the dispersed phase. Axial dispersed plug flow model with open-open boundary condition and two points measurement method was used to simulate the hydrodynamics of dispersed phase. It has been observed that the axial mixing and holdup of dispersed phase increases with increase in pulsation frequency and amplitude until a maximum value is achieved while slip velocity decreases with increase in pulsation frequency and amplitude until it approaches a minimum value. Short lived and low energy radiotracer (99m)Tc in the form of sodium pertechnetate was found to be a good water tracer to study the hydrodynamics of a liquid-liquid extraction pulsed sieve plate column operating with two immiscible liquids, water and kerosene. Axial dispersed plug flow model with open-open boundary condition was found to be a suitable model to describe the hydrodynamics of dispersed phase in the pulsed sieve plate extraction column.

Development of porous lamellar poly(L-lactic acid) scaffolds by conventional injection molding process.

PubMed

Ghosh, Satyabrata; Viana, Júlio C; Reis, Rui L; Mano, João F

2008-07-01

A novel fabrication technique is proposed for the preparation of unidirectionally oriented, porous scaffolds by selective polymer leaching from lamellar structures created by conventional injection molding. The proof of the concept is implemented using a 50/50 wt.% poly(L-lactic acid)/poly(ethylene oxide) (PLLA/PEO) blend. With this composition, the PLLA and PEO blend is biphasic, containing a homogeneous PLLA/PEO phase and a PEO-rich phase. The two phases were structured using injection molding into well-defined alternating layers of homogeneous PLLA/PEO phase and PEO-rich phase. Leaching of water-soluble PEO from the PEO-rich phase produces macropores, and leaching of phase-separated PEO from the initially homogeneous PLLA/PEO phase produces micropores in the lamellae. Thus, scaffolds with a macroporous lamellar architecture with microporous walls can be produced. The lamellae are continuous along the flow direction, and a continuous lamellar thickness of less than 1 microm could be achieved. Porosities of 57-74% and pore sizes of around 50-100 microm can be obtained using this process. The tensile elastic moduli of the porous constructs were between 580 and 800 MPa. We propose that this organic-solvent-free method of preparing lamellar scaffolds with good mechanical properties, and the reproducibility associated with the injection molding technique, holds promise for a wide range of guided tissue engineering applications.

Operation condition for continuous anti-solvent crystallization of CBZ-SAC cocrystal considering deposition risk of undesired crystals

NASA Astrophysics Data System (ADS)

Nishimaru, Momoko; Nakasa, Miku; Kudo, Shoji; Takiyama, Hiroshi

2017-07-01

Crystallization operation of cocrystal production has deposition risk of undesired crystals. Simultaneously, continuous manufacturing processes are focused on. In this study, conditions for continuous cocrystallization considering risk reduction of undesired crystals deposition were investigated on the view point of thermodynamics and kinetics. The anti-solvent cocrystallization was carried out in four-component system of carbamazepine, saccharin, methanol and water. From the preliminary batch experiment, the relationships among undesired crystal deposition, solution composition decided by mixing ratio of solutions, and residence time for the crystals were considered, and then the conditions of continuous experiment were decided. Under these conditions, the continuous experiment was carried out. The XRD patterns of obtained crystals in the continuous experiment showed that desired cocrystals were obtained without undesired crystals. This experimental result was evaluated by using multi-component phase diagrams from the view point of the operation point's movement. From the evaluation, it was found that there is a certain operation condition which the operation point is fixed with time in the specific domain without the deposition risk of undesired single component crystals. It means the possibility of continuous production of cocrystals without deposition risk of undesired crystals was confirmed by using multi-component phase diagrams.

Pretreatment of industrial wastewater containing phthalate esters by centrifugation

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

Petrosky, C.J.; Vidic, R.D.

1996-11-01

In this study, a full-scale commercial centrifuge was used to treat, on a continuous basis, the entire wastewater stream generated by a chemical manufacturing facility which produces a variety of phthalate, adipate, maleate, and trimellitate esters. The wastewater from this facility is comprised of process water, equipment was water, and rain water runoff containing varying concentrations of bis(2-ethylhexyl) phthalate (BEHP), di-n-octyl phthalate (DNOP), and di-n-butyl phthalate (DNBP) esters in addition to mono-ester salts and alcohols. The wastewater is discharged to the local Publicly Owned Treatment Works (POTW) under pretreatment regulations which specify an effluent limitation of 5.0 mg/L on themore » total toxic organic (TTO) concentration which can be placed on the combined BEHP, DNOP, and DNBP ester concentration. Various esters and long chain alcohols present in the wastewater have very low water solubilities and are considered immiscible. They form a dispersed phase in the wastewater that has a specific gravity in the range of 0.88 to 0.93. Separation of the dispersed phase containing the regulated esters from the heavier water phase to consistently below 5.0 mg/L poses a challenge due to the stability of this colloidal suspension. The objective of this study was to evaluate the effectiveness of centrifugation in meeting the 5.0 mg/L effluent limit on the total BEHP, DNOP, and DNBP ester concentration.« less

Comparison of vapor formation of water at the solid/water interface to colloidal solutions using optically excited gold nanostructures.

PubMed

Baral, Susil; Green, Andrew J; Livshits, Maksim Y; Govorov, Alexander O; Richardson, Hugh H

2014-02-25

The phase transformation properties of liquid water to vapor is characterized by optical excitation of the lithographically fabricated single gold nanowrenches and contrasted to the phase transformation properties of gold nanoparticles located and optically excited in a bulk solution system [two and three dimensions]. The 532 nm continuous wave excitation of a single gold nanowrench results in superheating of the water to the spinodal decomposition temperature of 580 ± 20 K with bubble formation below the spinodal decomposition temperature being a rare event. Between the spinodal decomposition temperature and the boiling point liquid water is trapped into a metastable state because a barrier to vapor nucleation exists that must be overcome before the thermodynamically stable state is realized. The phase transformation for an optically heated single gold nanowrench is different from the phase transformation of optically excited colloidal gold nanoparticles solution where collective heating effects dominates and leads to the boiling of the solution exactly at the boiling point. In the solution case, the optically excited ensemble of nanoparticles collectively raises the ambient temperature of water to the boiling point where liquid is converted into vapor. The striking difference in the boiling properties of the single gold nanowrench and the nanoparticle solution system can be explained in terms of the vapor-nucleation mechanism, the volume of the overheated liquid, and the collective heating effect. The interpretation of the observed regimes of heating and vaporization is consistent with our theoretical modeling. In particular, we explain with our theory why the boiling with the collective heating in a solution requires 3 orders of magnitude less intensity compared to the case of optically driven single nanowrench.

Pastes: what do they contain? How do they work?

PubMed

Juch, R D; Rufli, T; Surber, C

1994-01-01

Pastes are semisolid stiff preparations containing a high proportion of finely powdered material. Powders such as zinc oxide, titanium dioxide, starch, kaolin or talc are incorporated in high concentrations into a preferably lipophilic, greasy vehicle. A clinically distinctive feature which is generally attributed to pastes is the quality to absorb exudates by nature of the powder or other absorptive components. Reviewing the various pharmacopoeias serious doubts arise from the various formulas of pastes and their absorptive features. The zinc oxide pastes of the USP XXII, the DAB 10 and BP 88 (US, German and British pharmacopoeias). are composed of petrolatum, zinc oxide and starch. Petrolatum, a highly lipophilic, water-immiscible vehicle surrounds the powder particles preventing any absorption of water or exudates. The goal of our investigation was to test a simple experimental setting to characterize the clinically important absorptive feature of powders and pastes. The absorptive features of the powders were determined by the method of Enslin. The absorptive features of the paste preparations were calculated from the weight difference between the paste preparation before and after incubation with water using a simple standardized procedure. The absorptive features of titanium dioxide, zinc oxide, kaolin, corn starch and methylcellulose powder in pharmacopoeia quality were determined. Zinc oxide and kaolin powder showed the highest absorption of 1,000 mg water/g powder (100%). The water absorption of corn starch and titanium dioxide was 700 and 450 mg/g powder, respectively. The absorptive features of a series of paste preparations were studied in a simple experimental setting. The data show that two-phase pastes consisting of two immiscible components, one (the dispersed or inner phase; powder) being suspended in the other (the continuous or outer phase; lipophilic vehicle), have no absorptive features. In contrast, three-phase pastes consisting of a hydrophilic two-phase emulsion with high concentrations of incorporated powder (cream pastes) show considerable water uptake. We conclude that the classical two-phase pastes such as the zinc oxide pastes have no absorptive features. On the contrary, these formulations are highly occlusive. Therefore lipophilic pastes are only indicated when protection of intact skin against aggressive body exudates and humidity is required. The hydrophilic three-phase pastes or cream pastes show considerable water uptake and fulfil common expectations of pastes to dry the skin.

Plant-water relationships in the Great Basin Desert of North America derived from Pinus monophylla hourly dendrometer records.

PubMed

Biondi, Franco; Rossi, Sergio

2015-08-01

Water is the main limiting resource for natural and human systems, but the effect of hydroclimatic variability on woody species in water-limited environments at sub-monthly time scales is not fully understood. Plant-water relationships of single-leaf pinyon pine (Pinus monophylla) were investigated using hourly dendrometer and environmental data from May 2006 to October 2011 in the Great Basin Desert, one of the driest regions of North America. Average radial stem increments showed an annual range of variation below 1.0 mm, with a monotonic steep increase from May to July that yielded a stem enlargement of about 0.5 mm. Stem shrinkage up to 0.2 mm occurred in late summer, followed by an abrupt expansion of up to 0.5 mm in the fall, at the arrival of the new water year precipitation. Subsequent winter shrinkage and enlargement were less than 0.3 mm each. Based on 4 years with continuous data, diel cycles varied in both timing and amplitude between months and years. Phase shifts in circadian stem changes were observed between the growing season and the dormant one, with stem size being linked to precipitation more than to other water-related indices, such as relative humidity or soil moisture. During May-October, the amplitude of the phases of stem contraction, expansion, and increment was positively related to their duration in a nonlinear fashion. Changes in precipitation regime, which affected the diel phases especially when lasting more than 5-6 h, could substantially influence the dynamics of water depletion and replenishment in single-leaf pinyon pine.

Plant-water relationships in the Great Basin Desert of North America derived from Pinus monophylla hourly dendrometer records

NASA Astrophysics Data System (ADS)

Biondi, Franco; Rossi, Sergio

2015-08-01

Water is the main limiting resource for natural and human systems, but the effect of hydroclimatic variability on woody species in water-limited environments at sub-monthly time scales is not fully understood. Plant-water relationships of single-leaf pinyon pine ( Pinus monophylla) were investigated using hourly dendrometer and environmental data from May 2006 to October 2011 in the Great Basin Desert, one of the driest regions of North America. Average radial stem increments showed an annual range of variation below 1.0 mm, with a monotonic steep increase from May to July that yielded a stem enlargement of about 0.5 mm. Stem shrinkage up to 0.2 mm occurred in late summer, followed by an abrupt expansion of up to 0.5 mm in the fall, at the arrival of the new water year precipitation. Subsequent winter shrinkage and enlargement were less than 0.3 mm each. Based on 4 years with continuous data, diel cycles varied in both timing and amplitude between months and years. Phase shifts in circadian stem changes were observed between the growing season and the dormant one, with stem size being linked to precipitation more than to other water-related indices, such as relative humidity or soil moisture. During May-October, the amplitude of the phases of stem contraction, expansion, and increment was positively related to their duration in a nonlinear fashion. Changes in precipitation regime, which affected the diel phases especially when lasting more than 5-6 h, could substantially influence the dynamics of water depletion and replenishment in single-leaf pinyon pine.

Making and breaking bridges in a Pickering emulsion.

PubMed

French, David J; Taylor, Phil; Fowler, Jeff; Clegg, Paul S

2015-03-01

Particle bridges form in Pickering emulsions when the oil-water interfacial area generated by an applied shear is greater than that which can be stabilised by the available particles and the particles have a slight preference for the continuous phase. They can subsequently be broken by low shear or by modifying the particle wettability. We have developed a model oil-in-water system for studying particle bridging in Pickering emulsions stabilised by fluorescent Stöber silica. A mixture of dodecane and isopropyl myristate was used as the oil phase. We have used light scattering and microscopy to study the degree to which emulsions are bridged, and how this is affected by parameters including particle volume fraction, particle wettability and shear rate. We have looked for direct evidence of droplets sharing particles using freeze fracture scanning electron microscopy. We have created strongly aggregating Pickering emulsions using our model system. This aggregating state can be accessed by varying several different parameters, including particle wettability and particle volume fraction. Particles with a slight preference for the continuous phase are required for bridging to occur, and the degree of bridging increases with increasing shear rate but decreases with increasing particle volume fraction. Particle bridges can subsequently be removed by applying low shear or by modifying the particle wettability. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

A Fuzzy Expert System for Fault Management of Water Supply Recovery in the ALSS Project

NASA Technical Reports Server (NTRS)

Tohala, Vapsi J.

1998-01-01

Modeling with a new software is a challenge. CONFIG is a challenge and is design to work with many types of systems in which discrete and continuous processes occur. The CONFIG software was used to model the two subsystem of the Water Recovery system: ICB and TFB. The model worked manually only for water flows with further implementation to be done in the future. Activities in the models are stiff need to be implemented based on testing of the hardware for phase III. More improvements to CONFIG are in progress to make it a more user friendly software.

Data uses and funding for the stream-gaging program in Utah

USGS Publications Warehouse

Cruff, R.W.

1986-01-01

This report documents the results of the first phase of a study of the cost effectiveness of the streamflow-information program in Utah. Data use, funding, and data availability are described for the streamflow stations operated by the U.S. Geological Survey; and a history of the stream-gaging program is given. During the 1984 water year, 214 continuous streamflow stations were operated on a budget of $854,000. Data from most stations have multiple uses and all stations presently have sufficient justification for continuation.

Importance of mechanical disaggregation in chemical weathering in a cold alpine environment, San Juan Mountains, Colorado

USGS Publications Warehouse

Hoch, A.R.; Reddy, M.M.; Drever, J.I.

1999-01-01

Weathering of welded tuff near the summit of Snowshoe Mountain (3660 m) in southwestern Colorado was studied by analyzing infiltrating waters in the soil and associated solid phases. Infiltrating waters exhibit anomalously high potassium to silica ratios resulting from dissolution of a potassium-rich glass that occurs as a trace phase in the rock. In laboratory experiments using rock from the field site, initial dissolution generated potassium-rich solutions similar to those observed in the field. The anomalous potassium release decreased over time (about 1 month), after which the dominant cation was calcium, with a much lower potassium to silica ratio. The anomalous potassium concentrations observed in the infiltrating soil solutions result from weathering of freshly exposed rock surfaces. Continual mechanical disaggregation of the rock due to segregation freezing exposes fresh glass to weathering and thus maintains the source of potassium for the infiltrating water. The ongoing process of creation of fresh surfaces by physical processes is an important influence on the composition of infiltrating waters in the vadose zone.

Water quality of the Little Arkansas River and Equus Beds Aquifer before and concurrent with large-scale artificial recharge, south-central Kansas, 1995-2012

USGS Publications Warehouse

Tappa, Daniel J.; Lanning-Rush, Jennifer L.; Klager, Brian J.; Hansen, Cristi V.; Ziegler, Andrew C.

2015-01-01

Recharge activities at Phase I recharge wells have not resulted in substantial effects on groundwater quality in the area, likely because the total amount of water recharged is relatively small (1 billion gallons) compared to aquifer storage volume (greater than 990 billion gallons in winter 2012). The eastward movement of the Burrton chloride plume is likely being slowed by a line of recharge locations associated with Phase I; however, chloride concentrations in deep groundwater still advanced to less than one half mile from the central part of the study area. Water-quality constituents of concern (major ions, nutrients, trace elements, triazine herbicides, and fecal indicator bacteria) have not increased substantially and are likely more affected by climatological (natural recharge by precipitation) and natural (geochemical oxidation/reduction, metabolic and decay rates) processes than artificial recharge. Arsenic remains a water-quality constituent of concern because of natural and continued persistence of concentrations exceeding the Federal maximum contaminant level of 10 micrograms per liter, especially in the deeper parts of theEquus Beds aquifer.

Determination of dissolved-phase pesticides in surface water from the Yakima River basin, Washington, using the Goulden large-sample extractor and gas chromatography/mass spectrometer

USGS Publications Warehouse

Foster, Gregory D.; Gates, Paul M.; Foreman, William T.; McKenzie, Stuart W.; Rinella, Frank A.

1993-01-01

Concentrations of pesticides in the dissolved phase of surface water samples from the Yakima River basin, WA, were determined using preconcentration in the Goulden large-sample extractor (GLSE) and gas chromatography/mass spectrometry (GC/MS) analysis. Sample volumes ranging from 10 to 120 L were processed with the GLSE, and the results from the large-sample analyses were compared to those derived from 1-L continuous liquid-liquid extractions Few of the 40 target pesticides were detected in 1-L samples, whereas large-sample preconcentration in the GLSE provided detectable levels for many of the target pesticides. The number of pesticides detected in GLSE processed samples was usually directly proportional to sample volume, although the measured concentrations of the pesticides were generally lower at the larger sample volumes for the same water source. The GLSE can be used to provide lower detection levels relative to conventional liquid-liquid extraction in GC/MS analysis of pesticides in samples of surface water.

International Space Station Potable Water Characterization for 2013

NASA Technical Reports Server (NTRS)

Straub, John E. II; Plumlee, Debrah K.; Schultz, John R..; Mudgett, Paul D.

2014-01-01

In this post-construction, operational phase of International Space Station (ISS) with an ever-increasing emphasis on its use as a test-bed for future exploration missions, the ISS crews continue to rely on water reclamation systems for the majority of their water needs. The onboard water supplies include US Segment potable water from humidity condensate and urine, Russian Segment potable water from condensate, and ground-supplied potable water, as reserve. In 2013, the cargo returned on the Soyuz 32-35 flights included archival potable water samples collected from Expeditions 34-37. The Water and Food Analytical Laboratory at the NASA Johnson Space Center continued its long-standing role of performing chemical analyses on ISS return water samples to verify compliance with potable water quality specifications. This paper presents and discusses the analytical results for potable water samples returned from Expeditions 34-37, including a comparison to ISS quality standards. During the summer of 2013, the U.S. Segment potable water experienced an anticipated temporary rise and fall in total organic carbon (TOC) content, as the result of organic contamination breaking through the water system's treatment process. Analytical results for the Expedition 36 archival samples returned on Soyuz 34 confirmed that dimethylsilanediol was once again the responsible contaminant, just as it was for comparable TOC rises in 2010 and 2012. Discussion herein includes the use of the in-flight Total Organic Carbon Analyzer (TOCA) as a key monitoring tool for tracking these TOC rises and scheduling appropriate remediation action.

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

Gallo, Paola; Amann-Winkel, Katrin; Angell, Charles Austen

Water is the most abundant liquid on earth and also the substance with the largest number of anomalies in its properties. It is a prerequisite for life and as such a most important subject of current research in chemical physics and physical chemistry. In spite of its simplicity as a liquid, it has an enormously rich phase diagram where different types of ices, amorphous phases, and anomalies disclose a path that points to unique thermodynamics of its supercooled liquid state that still hides many unraveled secrets. In this review we describe the behavior of water in the regime from ambientmore » conditions to the deeply supercooled region. The review describes simulations and experiments on this anomalous liquid. Several scenarios have been proposed to explain the anomalous properties that become strongly enhanced in the supercooled region. Among those, the second critical-point scenario has been investigated extensively, and at present most experimental evidence point to this scenario. Starting from very low temperatures, a coexistence line between a high-density amorphous phase and a low-density amorphous phase would continue in a coexistence line between a high-density and a low-density liquid phase terminating in a liquid–liquid critical point, LLCP. On approaching this LLCP from the one-phase region, a crossover in thermodynamics and dynamics can be found. This is discussed based on a picture of a temperature-dependent balance between a high-density liquid and a low-density liquid favored by, respectively, entropy and enthalpy, leading to a consistent picture of the thermodynamics of bulk water. Ice nucleation is also discussed, since this is what severely impedes experimental investigation of the vicinity of the proposed LLCP. Experimental investigation of stretched water, i.e., water at negative pressure, gives access to a different regime of the complex water diagram. Different ways to inhibit crystallization through confinement and aqueous solutions are discussed through results from experiments and simulations using the most sophisticated and advanced techniques. These findings represent tiles of a global picture that still needs to be completed. In conclusion, some of the possible experimental lines of research that are essential to complete this picture are explored.« less

Averaged variational principle for autoresonant Bernstein-Greene-Kruskal modes

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

Khain, P.; Friedland, L.

2010-10-15

Whitham's averaged variational principle is applied in studying dynamics of formation of autoresonant (continuously phase-locked) Bernstein-Greene-Kruskal (BGK) modes in a plasma driven by a chirped frequency ponderomotive wave. A flat-top electron velocity distribution is used as a model allowing a variational formulation within the water bag theory. The corresponding Lagrangian, averaged over the fast phase variable yields evolution equations for the slow field variables, allows uniform description of all stages of excitation of driven-chirped BGK modes, and predicts modulational stability of these nonlinear phase-space structures. Numerical solutions of the system of slow variational equations are in good agreement with Vlasov-Poissonmore » simulations.« less

National Program for Inspection of Non-Federal Dams. Lower Reservoir Dam (NH 00048), NHWRB Number 108.05, Connecticut River Basin, Hanover, New Hampshire. Phase I Inspection Report.

DTIC Science & Technology

1979-11-01

reservoirs, Upper Reservoir and Reservoir No. 3. The reservoir supplies to the water destribution system by gravity. h. Design and Construction History. o...continual supply to the water , destribution system as the main service area is fed by gravity. The waste pipe is usually closed. The flashboards on...however, no design calculations or b construction data were revealed.. The visual inspection revealed that the dam is in poor condition. The visual

Effects of aquifer storage and recovery activities on water quality in the Little Arkansas River and Equus Beds Aquifer, south-central Kansas, 2011–14

USGS Publications Warehouse

Stone, Mandy L.; Garrett, Jessica D.; Poulton, Barry C.; Ziegler, Andrew C.

2016-07-18

The Equus Beds aquifer in south-central Kansas is aprimary water source for the city of Wichita. The Equus Beds aquifer storage and recovery (ASR) project was developed to help the city of Wichita meet increasing current (2016) and future water demands. The Equus Beds ASR project pumps water out of the Little Arkansas River during above-base flow conditions, treats it using drinking-water quality standards as a guideline, and recharges it into the Equus Beds aquifer for later use. Phase II of the Equus Beds ASR project currently (2016) includes a river intake facility and a surface-water treatment facility with a 30 million gallon per day capacity. Water diverted from the Little Arkansas River is delivered to an adjacent presedimentation basin for solids removal. Subsequently, waste from the surface-water treatment facility and the presedimentation basin is returned to the Little Arkansas River through a residuals return line. The U.S. Geological Survey, in cooperation with the city of Wichita, developed and implemented a hydrobiological monitoring program as part of the ASR project to characterize and quantify the effects of aquifer storage and recovery activities on the Little Arkansas River and Equus Beds aquifer water quality.Data were collected from 2 surface-water sites (one upstream and one downstream from the residuals return line), 1 residuals return line site, and 2 groundwater well sites (each having a shallow and deep part): the Little Arkansas River upstream from the ASR facility near Sedgwick, Kansas (upstream surface-water site 375350097262800), about 0.03 mile (mi) upstream from the residuals return line site; the Little Arkansas River near Sedgwick, Kans. (downstream surface-water site 07144100), about 1.68 mi downstream from the residuals return line site; discharge from the Little Arkansas River ASR facility near Sedgwick, Kansas (residuals return line site 375348097262800); 25S 01 W 07BCCC01 SMW–S11 near CW36 (MW–7 shallow groundwater well site 375327097285401); 25S01 W 07BCCC02 DMW–S10 near CW36 (MW–7 deep groundwater well site 375327097285402); 25S 01W 07BCCA01 SMW–S13 near CW36 (MW–8 shallow groundwater well site 375332097284801); and 25S 01W 07BCCA02 DMW–S14 near CW36 (MW–8 deep groundwater well site 375332097284802). The U.S. Geological Survey, in cooperation with the city of Wichita, assessed the effects of the ASR Phase II facility residuals return line discharges on stream quality of the Little Arkansas River by measuring continuous physicochemical properties and collecting discrete water-quality and sediment samples for about 2 years pre- (January 2011 through April 2013) and post-ASR (May 2013 through December 2014) Phase II facility operation upstream and downstream from the ASR Phase II facility. Additionally, habitat variables were quantified and macroinvertebrate and fish communities were sampled upstream and downstream from the ASR Phase II facility during the study period. To assess the effects of aquifer recharge on Equus Beds groundwater quality, continuous physicochemical properties were measured and discrete water-quality samples were collected before and during the onset of Phase II aquifer recharge in two (shallow and deep) groundwater wells.Little Arkansas River streamflow was about 10 times larger after the facility began operating because of greater rainfall. Residuals return line release volumes were a very minimal proportion (0.06 percent) of downstream streamflow volume during the months the ASR facility was operating. Upstream and downstream continuously measured water temperature and dissolved oxygen median differences were smaller post-ASR than pre-ASR. Turbidity generally was smaller at the downstream site throughout the study period and decreased at both sites after the ASR Phase II facility began discharging despite a median residuals return line turbidity that was about an order of magnitude larger than the median turbidity at the downstream site. Upstream and downstream continuously measured turbidity median differences were larger post-ASR than pre-ASR. Median post-ASR continuously measured nitrite plus nitrate and continuously computed total suspended solids and suspended-sediment concentrations were smaller than pre-ASR likely because of higher streamflows and dilution; whereas, median continuously computed dissolved and total organic carbon concentrations were larger likely because of higher streamflows and runoff conditions.None of the discretely measured water-quality constituents (dissolved and suspended solids, primary ions, suspended sediment, nutrients, carbon, trace elements, viral and bacterial indicators, and pesticides) in surface water were significantly different between the upstream and downstream sites after the ASR Phase II facility began discharging; however, pre-ASR calcium, sodium, hardness, manganese, and arsenate concentrations were significantly larger at the upstream site, which indicates that some water-quality conditions at the upstream and downstream sites were more similar post-ASR. Most of the primary constituents that make up dissolved solids decreased at both sites after the ASR Phase II facility began operation. Discretely collected total suspended solids concentrations were similar between the upstream and downstream sites before the facility began operating but were about 27 percent smaller at the downstream site after the facility began operating, despite the total suspended solids concentrations in the residuals return line being 15 times larger than the downstream site.Overall habitat scores were indicative of suboptimal conditions upstream and downstream from the ASR Phase II facility throughout the study period. Substrate fouling and sediment deposition mean scores indicated marginal conditions at the upstream and downstream sites during the study period, demonstrating that sediment deposition was evident pre- and post-ASR and no substantial changes in these habitat characteristics were noted after the ASR Phase II facility began discharging. Macroinvertebrate community composition (evaluated using functional feeding, behavioral, and tolerance metrics) generally was similar between sites during the study period. Fewer macroinvertebrate metrics were significant between the upstream and downstream sites post-ASR (6) than pre-ASR (14), which suggests that macroinvertebate communities were more similar after the ASR facility began discharging. Upstream-downstream comparisons in macroinvertebrate aquatic-life-support metrics had no significant differences for the post-ASR time period and neither site was fully supporting for any of the Kansas Department of Health and Environment aquatic-life-support metrics (Macroinvertebrate Biotic Index; Kansas Biotic Index with tolerances for nutrients and oxygen-demanding substances; Ephemeroptera, Plecoptera, and Trichoptera [EPT] richness; and percentage of EPT species). Overall, using macroinvertebrate aquatic life-support criteria from the Kansas Department of Health and Environment, upstream and downstream sites were classified as partially supporting before and after the onset of ASR facility operations. Fish community trophic status and tolerance groups generally were similar among sites during the study period. Fish community Little Arkansas River Basin Index of Biotic Integrity scores at the upstream and downstream sites were indicative of fair-to-good conditions before the facility began operating and decreased to fair conditions after the facility began operating.Groundwater physicochemical changes concurrent with the beginning of recharge operations at the Sedgwick basin were more pronounced in shallow groundwater. No constituent concentrations in the pre-recharge period in comparison to the post-recharge period increased to concentrations exceeding drinking water regulations; however, nitrate decreased significantly from a pre-recharge exceedance of the U.S. Environmental Protection Agency maximum contaminant level to a post recharge nonexceedance. Shallow groundwater chemical concentrations or rates of detection increased after artificial recharge began for the ions potassium, chloride, and fluoride; phosphorus and organic carbon species; trace elements barium, manganese, nickel, arsenate, arsenic, and boron; agricultural pesticides atrazine, metolachlor, metribuzin, and simazine; organic disinfection byproducts bromodichloromethane and trichloromethane; and gross beta levels. Additionally, water temperature, and pH were larger after recharge began; and total solids and slime-forming bacteria concentrations and densities were smaller. Total solids, nitrate, and selenium significantly decreased; and potassium, chloride, nickel, arsenic, fluoride, phosphorus and carbon species, and gross beta levels significantly increased in shallow groundwater after artificial recharge. Results of biological activity reaction tests indicated that water quality microbiology was different before and after artificial recharge began; at times, these differences may lead to changes in dominant bacterial populations that, in turn, may lead to formation and expansion in populations that may cause bioplugging and other unwanted effects. Calcite, iron (II) hydroxide, hydroxyapatite, and similar minerals, had shifts in saturation indices that generally were from undersaturation toward equilibrium and, in some cases, toward oversaturation. These shifts toward neutral saturation indices might suggest reduced weathering of the minerals present in the Equus Beds aquifer. Chemical weathering in the shallow parts of the aquifer may be accelerated because of the increased water temperatures and the system is more vulnerable to clogged pores and mineral dissolution as the equilibrium state is affected by recharge and withdrawal. When oversaturation is indicated for iron minerals, plugging of aquifer materials may happen.

Lecithin organogels used as bioactive compounds carriers. A microdomain properties investigation.

PubMed

Avramiotis, Spyridon; Papadimitriou, Vassiliki; Hatzara, Elina; Bekiari, Vlasoula; Lianos, Panagiotis; Xenakis, Aristotelis

2007-04-10

Organogels were obtained by adding small amounts of water to a solution of lecithin in organic solvents. Either isooctane or isopropyl palmitate and isopropyl myristate were used as the continuous organic phase of the gels. EPR spectroscopy using both DSA membrane-sensitive and lipophilic spin probes was applied to define the dynamic structure of the surfactant monolayer and the continuous oil phase of lecithin organogels. It was found that by increasing the water quantity, an increase of the polar head area per lecithin molecule was induced, and as a consequence the total interface expanded. It was found that the use of esters as organic solvents induced a decrease of the size of the dispersed structures. The interconnection of the aqueous microdomains and their dynamics were monitored by both static and time-resolved fluorescence quenching spectroscopy using Ru(bipy)32+ as fluorophore and Fe(CN)63- as quencher. It was found that the rates of inter- and/or intra-micellar exchange of water molecules were very slow because they appeared quite immobilized close to the lecithin polar heads. According to the results of the dynamic studies, appropriate organogels were formulated and used to incorporate model bioactive compounds with medicinal or cosmetic interest such as caffeine and theophylline. When these systems were tested for trans-membrane diffusion, they showed a 24 h permeation of 20% and 35%, respectively.

Electrochemically driven emulsion inversion

NASA Astrophysics Data System (ADS)

Johans, Christoffer; Kontturi, Kyösti

2007-09-01

It is shown that emulsions stabilized by ionic surfactants can be inverted by controlling the electrical potential across the oil-water interface. The potential dependent partitioning of sodium dodecyl sulfate (SDS) was studied by cyclic voltammetry at the 1,2-dichlorobenzene|water interface. In the emulsion the potential control was achieved by using a potential-determining salt. The inversion of a 1,2-dichlorobenzene-in-water (O/W) emulsion stabilized by SDS was followed by conductometry as a function of added tetrapropylammonium chloride. A sudden drop in conductivity was observed, indicating the change of the continuous phase from water to 1,2-dichlorobenzene, i.e. a water-in-1,2-dichlorobenzene emulsion was formed. The inversion potential is well in accordance with that predicted by the hydrophilic-lipophilic deviation if the interfacial potential is appropriately accounted for.

PEGylated lipid nanocapsules with improved drug encapsulation and controlled release properties.

PubMed

Hervella, Pablo; Alonso-Sande, Maria; Ledo, Francisco; Lucero, Maria L; Alonso, Maria J; Garcia-Fuentes, Marcos

2014-01-01

Drugs with poor lipid and water solubility are some of the most challenging to formulate in nanocarriers, typically resulting in low encapsulation efficiencies and uncontrolled release profiles. PEGylated nanocapsules (PEG-NC) are known for their amenability to diverse modifications that allow the formation of domains with different physicochemical properties, an interesting feature to address a drug encapsulation problem. We explored this problem by encapsulating in PEG-NC the promising anticancer drug candidate F10320GD1, used herein as a model for compounds with such characteristics. The nanocarriers were prepared from Miglyol(®), lecithin and PEG-sterate through a solvent displacement technique. The resulting system was a homogeneous suspension of particles with size around 200 nm. F10320GD1 encapsulation was found to be very poor (<15%) if PEG-NC were prepared using water as continuous phase; but we were able to improve this value to 85% by fixing the pH of the continuous phase to 9. Interestingly, this modification also improved the controlled release properties and the chemical stability of the formulation during storage. These differences in pharmaceutical properties together with physicochemical data suggest that the pH of the continuous phase used for PEG-NC preparation can modify drug allocation, from the external shell towards the inner lipid core of the nanocapsules. Finally, we tested the bioactivity of the drug-loaded PEG-NC in several tumor cell lines, and also in endothelial cells. The results indicated that drug encapsulation led to an improvement on drug cytotoxicity in tumor cells, but not in non-tumor endothelial cells. Altogether, the data confirms that PEG-NC show adequate delivery properties for F10320GD1, and underlines its possible utility as an anticancer therapy.

Active oil-water interfaces: buckling and deformation of oil drops by bacteria

NASA Astrophysics Data System (ADS)

Juarez, Gabriel; Stocker, Roman

2014-11-01

Bacteria are unicellular organisms that seek nutrients and energy for growth, division, and self-propulsion. Bacteria are also natural colloidal particles that attach and self-assemble at liquid-liquid interfaces. Here, we present experimental results on active oil-water interfaces that spontaneously form when bacteria accumulate or grow on the interface. Using phase-contrast and fluorescence microscopy, we simultaneously observed the dynamics of adsorbed Alcanivorax bacteria and the oil-water interface within microfluidic devices. We find that, by growing and dividing, adsorbed bacteria form a jammed monolayer of cells that encapsulates the entire oil drop. As bacteria continue to grow at the interface, the drop buckles and the interface undergoes strong deformations. The bacteria act to stabilize non-equilibrium shapes of the oil-phase such wrinkling and tubulation. In addition to presenting a natural example of a living interface, these findings shape our understanding of microbial degradation of oil and may have important repercussions on engineering interventions for oil bioremediation.

Electrophoretic manipulation of multiple-emulsion droplets

NASA Astrophysics Data System (ADS)

Schoeler, Andreas M.; Josephides, Dimitris N.; Chaurasia, Ankur S.; Sajjadi, Shahriar; Mesquida, Patrick

2014-02-01

Electrophoretic manipulation of multiple-emulsion oil-in-water-in-oil (O/W)/O and water-in-oil-in-water-in-oil (W/O/W)/O core-shell droplets is shown. It was found that the electrophoretic mobility of the droplets is determined solely by the outer water shell, regardless of size or composition of the inner droplets. It was observed that the surface charge of the outer water shell can be changed and the polarity can be reversed through contact with a biased electrode in a similar way as with simple W/O droplets. Furthermore, addition of the anionic surfactant, sodium dodecyl sulfate to the outer water shell reverses the initial polarity and hence, electrophoretic mobility of the core-shell droplets before contact with an electrode. The results have practical implications for the manipulation of oil droplets in a continuous oil phase.

Coal fly ash interaction with environmental fluids: Geochemical and strontium isotope results from combined column and batch leaching experiments

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

Brubaker, Tonya M; Stewart, Brian W; Capo, Rosemary C

2013-05-01

The major element and Sr isotope systematics and geochemistry of coal fly ash and its interactions with environmental waters were investigated using laboratory flow-through column leaching experiments (sodium carbonate, acetic acid, nitric acid) and sequential batch leaching experiments (water, acetic acid, hydrochloric acid). Column leaching of Class F fly ash samples shows rapid release of most major elements early in the leaching procedure, suggesting an association of these elements with soluble and surface bound phases. Delayed release of certain elements (e.g., Al, Fe, Si) signals gradual dissolution of more resistant silicate or glass phases as leaching continues. Strontium isotope resultsmore » from both column and batch leaching experiments show a marked increase in {sup 87}Sr/{sup 86}Sr ratio with continued leaching, yielding a total range of values from 0.7107 to 0.7138. For comparison, the isotopic composition of fluid output from a fly ash impoundment in West Virginia falls in a narrow range around 0.7124. The experimental data suggest the presence of a more resistant, highly radiogenic silicate phase that survives the combustion process and is leached after the more soluble minerals are removed. Strontium isotopic homogenization of minerals in coal does not always occur during the combustion process, despite the high temperatures encountered in the boiler. Early-released Sr tends to be isotopically uniform; thus the Sr isotopic composition of fly ash could be distinguishable from other sources and is a useful tool for quantifying the possible contribution of fly ash leaching to the total dissolved load in natural surface and ground waters.« less

Getting the Right Answers for the Right Reasons: Toward Predictive Molecular Simulations of Water with Many-Body Potential Energy Functions.

PubMed

Paesani, Francesco

2016-09-20

The central role played by water in fundamental processes relevant to different disciplines, including chemistry, physics, biology, materials science, geology, and climate research, cannot be overemphasized. It is thus not surprising that, since the pioneering work by Stillinger and Rahman, many theoretical and computational studies have attempted to develop a microscopic description of the unique properties of water under different thermodynamic conditions. Consequently, numerous molecular models based on either molecular mechanics or ab initio approaches have been proposed over the years. However, despite continued progress, the correct prediction of the properties of water from small gas-phase clusters to the liquid phase and ice through a single molecular model remains challenging. To large extent, this is due to the difficulties encountered in the accurate modeling of the underlying hydrogen-bond network in which both number and strength of the hydrogen bonds vary continuously as a result of a subtle interplay between energetic, entropic, and nuclear quantum effects. In the past decade, the development of efficient algorithms for correlated electronic structure calculations of small molecular complexes, accompanied by tremendous progress in the analytical representation of multidimensional potential energy surfaces, opened the doors to the design of highly accurate potential energy functions built upon rigorous representations of the many-body expansion (MBE) of the interaction energies. This Account provides a critical overview of the performance of the MB-pol many-body potential energy function through a systematic analysis of energetic, structural, thermodynamic, and dynamical properties as well as of vibrational spectra of water from the gas to the condensed phase. It is shown that MB-pol achieves unprecedented accuracy across all phases of water through a quantitative description of each individual term of the MBE, with a physically correct representation of both short- and long-range many-body contributions. Comparisons with experimental data probing different regions of the water potential energy surface from clusters to bulk demonstrate that MB-pol represents a major step toward the long-sought-after "universal model" capable of accurately describing the molecular properties of water under different conditions and in different environments. Along this path, future challenges include the extension of the many-body scheme adopted by MB-pol to the description of generic solutes as well as the integration of MB-pol in an efficient theoretical and computational framework to model acid-base reactions in aqueous environments. In this context, given the nontraditional form of the MB-pol energy and force expressions, synergistic efforts by theoretical/computational chemists/physicists and computer scientists will be critical for the development of high-performance software for many-body molecular dynamics simulations.

A new device for continuous monitoring the CO2 dissolved in water

NASA Astrophysics Data System (ADS)

de Gregorio, S.; Camarda, M.; Cappuzzo, S.; Giudice, G.; Gurrieri, S.; Longo, M.

2009-04-01

The measurements of dissolved CO2 in water are common elements of industrial processes and scientific research. In order to perform gas dissolved measurements is required to separate the dissolved gaseous phase from water. We developed a new device able to separate the gases phase directly in situ and well suitable for continuous measuring the CO2 dissolved in water. The device is made by a probe of a polytetrafluorethylene (PTFE) tube connected to an I.R. spectrophotometer (I.R.) and a pump. The PTFE is a polymeric semi-permeable membrane and allows the permeation of gas in the system. Hence, this part of the device is dipped in water in order to equilibrate the probe headspace with the dissolved gases. The partial pressure of the gas i in the headspace at equilibrium (Pi) follows the Henry's law: Pi=Hi•Ci, where Hi is the Henry's constant and Ci is the dissolved concentration of gas i. After the equilibrium is achieved, the partial pressure of CO2 inside the tube is equal to the partial pressure of dissolved CO2. The concentration of CO2 is measured by the I.R. connected to the tube. The gas is moved from the tube headspace to the I.R. by using the pump. In order to test the device and assess the best operating condition, several experimental were performed in laboratory. All the test were executed in a special apparatus where was feasible to create controlled atmospheres. Afterward the device has been placed in a draining tunnel sited in the Mt. Etna Volcano edifice (Italy). The monitored groundwater intercepts the Pernicana Fault, along which degassing phenomena are often observed. The values recorded by the station result in agreement with monthly directly measurements of dissolved CO2 partial pressure.

An Individualized, Perception-Based Protocol to Investigate Human Physiological Responses to Cooling

PubMed Central

Coolbaugh, Crystal L.; Bush, Emily C.; Galenti, Elizabeth S.; Welch, E. Brian; Towse, Theodore F.

2018-01-01

Cold exposure, a known stimulant of the thermogenic effects of brown adipose tissue (BAT), is the most widely used method to study BAT physiology in adult humans. Recently, individualized cooling has been recommended to standardize the physiological cold stress applied across participants, but critical experimental details remain unclear. The purpose of this work was to develop a detailed methodology for an individualized, perception-based protocol to investigate human physiological responses to cooling. Participants were wrapped in two water-circulating blankets and fitted with skin temperature probes to estimate BAT activity and peripheral vasoconstriction. We created a thermoesthesia graphical user interface (tGUI) to continuously record the subject's perception of cooling and shivering status during the cooling protocol. The protocol began with a 15 min thermoneutral phase followed by a series of 10 min cooling phases and concluded when sustained shivering (>1 min duration) occurred. Researchers used perception of cooling feedback (tGUI ratings) to manually adjust and personalize the water temperature at each cooling phase. Blanket water temperatures were recorded continuously during the protocol. Twelve volunteers (ages: 26.2 ± 1.4 years; 25% female) completed a feasibility study to evaluate the proposed protocol. Water temperature, perception of cooling, and shivering varied considerably across participants in response to cooling. Mean clavicle skin temperature, a surrogate measure of BAT activity, decreased (−0.99°C, 95% CI: −1.7 to −0.25°C, P = 0.16) after the cooling protocol, but an increase in supraclavicular skin temperature was observed in 4 participants. A strong positive correlation was also found between thermoesthesia and peripheral vasoconstriction (ρ = 0.84, P < 0.001). The proposed individualized, perception-based protocol therefore has potential to investigate the physiological responses to cold stress applied across populations with varying age, sex, body composition, and cold sensitivity characteristics. PMID:29593558

Development and Calibration of Two and Four Wire Water Surface Wave Height Measurement Systems

DTIC Science & Technology

1992-12-01

ON 0; "I$ -’ AGE S/N 0102-LF-01 -6603 Unclassified i Unclassified SECURITY CLASSIFICATION OF THIS PAGE 19 ABSTRACT (Continued) Hertz and decayed at 50...to 70 dB per decade, or ascu -5 to W-7 for both systems. Gravity wave phase speed and wavelength measurements were performed with capaci- tance system

Flow separation characteristics of unstable dispersions

NASA Astrophysics Data System (ADS)

Voulgaropoulos, Victor; Zhai, Lusheng; Angeli, Panagiota

2016-11-01

Drops of a low viscosity oil are introduced through a multi-capillary inlet during the flow of water in a horizontal pipe. The flow rates of the continuous water phase are kept in the turbulent region while the droplets are injected at similar flow rates (with oil fractions ranging from 0.15 to 0.60). The acrylic pipe (ID of 37mm) is approximately 7m long. Measurements are conducted at three different axial locations to illustrate how the flow structures are formed and develop along the pipe. Initial observations are made on the flow patterns through high-speed imaging. Stratification is observed for the flow rates studied, indicating that the turbulent dispersive forces are lower than the gravity ones. These results are complemented with a tomography system acquiring measurements at the same locations and giving the cross-sectional hold-up. The coalescence dynamics are strong in the dense-packed drop layer and thus measurements with a dual-conductance probe are conducted to capture any drop size changes. It is found that the drop size variations depend on the spatial configuration of the drops, the initial drop size along with the continuous and dispersed phase velocities. Project funded under Chevron Energy Technology.

Phase Change Material Trade Study: A Comparison Between Wax and Water for Manned Spacecraft

NASA Technical Reports Server (NTRS)

Quinn, Gregory; Hodgson, Ed; Stephan, Ryan

2010-01-01

Phase change material heat sinks have been recognized as an important tool in optimizing thermal control systems for space exploration vehicles and habitats that must deal with widely varying thermal loads and environments. In order to better focus technology investment in this arena, NASA has supported a trade study with the objective of identifying where the best potential pay-off can be found among identified aqueous and paraffin wax phase change materials and phase change material heat sink design approaches. The study used a representative exploration mission with well understood parameters to support the trade. Additional sensitivity studies were performed to ensure the applicability of study results across varying systems and destinations. Results from the study indicate that a water ice PCM heat sink has the potential to decrease the equivalent system mass of the mission s vehicle through a combination of a smaller heat sink and a slight 5% increase in radiator size or the addition of a lightweight heat pump. An evaluation of existing and emerging PCM heat sink technologies indicates that further significant mass savings should be achievable through continued development of those technologies. The largest mass savings may be realized by managing the location of the liquid and the solid in the heat sink to eliminate the melting and freezing pressure of wax and water, respectively, while also accommodating the high structural loads expected on future manned launch vehicles.

Plant growth-promoting rhizobacteria (PGPR) reduce evaporation and increase soil water retention

NASA Astrophysics Data System (ADS)

Zheng, W.; Zeng, S.; LaManna, J.; Bais, H.; Jin, Y.

2017-12-01

Enhancement of plant drought stress tolerance by plant growth promoting rhizobacteria (PGPR) has been increasingly documented in the literature. However, most studies to date have focused on PGPR-root/plant interactions; very little is known about PGPR's role in mediating physiochemical and hydrological changes in the rhizospheric soil that may impact plant drought stress tolerance. Our study seeks to advance mechanistic understanding of PGPR- mediated biophysical changes in the rhizospheric soil that may contribute to plant drought stress tolerance in addition to plant responses. In this study, we measured soil water retention characteristics, hydraulic conductivity, and water evaporation in soils with various textures (i.e., pure sand, sandy soil, and loam) as influenced by a PGPR (Bacillus subtilis strain UD1022) using the instrument HYPROP©. All PGPR-treated soils held more water, had reduced conductivity, and reduced evaporation rate compared to their corresponding controls. While changes in evaporation behavior, i.e., the transition from Stage I to Stage II, due to PGPR addition, occurred in all soils, they differed with soil texture: PGPR prolonged Stage I (but at lower evaporation rate than control) in the pure sand while the bacteria shortened Stage I in the other two soils. These results indicate that PGPR affects evaporation by modifying soil capillarity and wettability that control liquid phase continuity and capillary forces that sustain Stage I evaporation. SEM images show that PGPR promoted aggregation in the pure sand due to EPS production and biofilm formation. On the other hand, modification of soil wettability by EPS/biofilm thus water phase continuity and capillary driving forces likely dominated the PGPR effects in the other two soils. These findings improve our understanding of rhizosphere functions and have implications in developing biotechnologies using PGPR to increase soil water retention, which would help sustain agricultural production under restricted water availability.

Hydraulic fracture monitoring in hard rock at 410 m depth with an advanced fluid-injection protocol and extensive sensor array

NASA Astrophysics Data System (ADS)

Zang, Arno; Stephansson, Ove; Stenberg, Leif; Plenkers, Katrin; Specht, Sebastian; Milkereit, Claus; Schill, Eva; Kwiatek, Grzegorz; Dresen, Georg; Zimmermann, Günter; Dahm, Torsten; Weber, Michael

2017-02-01

In this paper, an underground experiment at the Äspö Hard Rock Laboratory (HRL) is described. Main goal is optimizing geothermal heat exchange in crystalline rock mass at depth by multistage hydraulic fracturing with minimal impact on the environment, that is, seismic events. For this, three arrays with acoustic emission, microseismicity and electromagnetic sensors are installed mapping hydraulic fracture initiation and growth. Fractures are driven by three different water injection schemes (continuous, progressive and pulse pressurization). After a brief review of hydraulic fracture operations in crystalline rock mass at mine scale, the site geology and the stress conditions at Äspö HRL are described. Then, the continuous, single-flow rate and alternative, multiple-flow rate fracture breakdown tests in a horizontal borehole at depth level 410 m are described together with the monitoring networks and sensitivity. Monitoring results include the primary catalogue of acoustic emission hypocentres obtained from four hydraulic fractures with the in situ trigger and localizing network. The continuous versus alternative water injection schemes are discussed in terms of the fracture breakdown pressure, the fracture pattern from impression packer result and the monitoring at the arrays. An example of multistage hydraulic fracturing with several phases of opening and closing of fracture walls is evaluated using data from acoustic emissions, seismic broad-band recordings and electromagnetic signal response. Based on our limited amount of in situ tests (six) and evaluation of three tests in Ävrö granodiorite, in the multiple-flow rate test with progressively increasing target pressure, the acoustic emission activity starts at a later stage in the fracturing process compared to the conventional fracturing case with continuous water injection. In tendency, also the total number and magnitude of acoustic events are found to be smaller in the progressive treatment with frequent phases of depressurization.

Soil water storage, rainfall and runoff relationships in a tropical dry forest catchment

NASA Astrophysics Data System (ADS)

Farrick, Kegan K.; Branfireun, Brian A.

2014-12-01

In forested catchments, the exceedance of rainfall and antecedent water storage thresholds is often required for runoff generation, yet to our knowledge these threshold relationships remain undescribed in tropical dry forest catchments. We, therefore, identified the controls of streamflow activation and the timing and magnitude of runoff in a tropical dry forest catchment near the Pacific coast of central Mexico. During a 52 day transition phase from the dry to wet season, soil water movement was dominated by vertical flow which continued until a threshold soil moisture content of 26% was reached at 100 cm below the surface. This satisfied a 162 mm storage deficit and activated streamflow, likely through lateral subsurface flow pathways. High antecedent soil water conditions were maintained during the wet phase but had a weak influence on stormflow. We identified a threshold value of 289 mm of summed rainfall and antecedent soil water needed to generate >4 mm of stormflow per event. Above this threshold, stormflow response and magnitude was almost entirely governed by rainfall event characteristics and not antecedent soil moisture conditions. Our results show that over the course of the wet season in tropical dry forests the dominant controls on runoff generation changed from antecedent soil water and storage to the depth of rainfall.

Characterization of caprylocaproyl macrogolglycerides based microemulsion drug delivery vehicles for an amphiphilic drug.

PubMed

Djordjevic, Ljiljana; Primorac, Marija; Stupar, Mirjana; Krajisnik, Danina

2004-03-01

Microemulsion systems composed of water, isopropyl myristate, PEG-8 caprylic/capric glycerides (Labrasol), and polyglyceryl-6 dioleate (Plurol Oleique), were investigated as potential drug delivery vehicles for an amphiphilic model drug (diclofenac diethylamine). Pseudo-ternary phase diagram of the investigated system, at constant surfactant/cosurfactant mass ratio (Km 4:1) was constructed at room temperature by titration, and the oil-to-surfactant/cosurfactant mass ratios (O/SC) that exhibit the maximum in the solubilization of water were found. This allowed the investigation of the continuous structural inversion from water-in-oil to oil-in-water microemulsions on dilution with water phase. Furthermore, electrical conductivity (sigma) of the system at Km 1:4, and O/SC 0.250 was studied, and the percolation phenomenon was observed. Conductivity and apparent viscosity (eta') measurement results well described colloidal microstructure of the selected formulations, including gradual changes during their formation. Moreover, sigma, eta', and pH values of six selected microemulsion vehicles which differ in water phase volume fraction (phi(w)) at the selected Km and O/SC values, were measured. In order to investigate the influence of the amphiphilic drug on the vehicle microstructures, each system was formulated with 1.16% (w/w) diclofenac diethylamine. Electrical conductivity, and eta' of the investigated systems were strongly affected by drug incorporation. The obtained results suggest that diclofenac diethylamine interacts with the specific microstructure of the investigated vehicles, and that the different drug release kinetics from these microemulsions may be expected. The investigated microemulsions should be very interesting as new drug carrier systems for dermal application of diclofenac diethylamine.

A compressible two-phase model for dispersed particle flows with application from dense to dilute regimes

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

McGrath, Thomas P., E-mail: thomas.p.mcgrath@navy.mil; St Clair, Jeffrey G.; Department of Mechanical and Aerospace Engineering, University of Florida, 231 MAE-A, P.O. Box 116250, Gainesville, Florida 32611

2016-05-07

Multiphase flows are present in many important fields ranging from multiphase explosions to chemical processing. An important subset of multiphase flow applications involves dispersed materials, such as particles, droplets, and bubbles. This work presents an Eulerian–Eulerian model for multiphase flows containing dispersed particles surrounded by a continuous media such as air or water. Following a large body of multiphase literature, the driving force for particle acceleration is modeled as a direct function of both the continuous-phase pressure gradient and the gradient of intergranular stress existing within the particle phase. While the application of these two components of driving force ismore » well accepted in much of the literature, other models exist in which the particle-phase pressure gradient itself drives particle motion. The multiphase model treats all phases as compressible and is derived to ensure adherence to the 2nd Law of Thermodynamics. The governing equations are presented and discussed, and a characteristic analysis shows the model to be hyperbolic, with a degeneracy in the case that the intergranular stress, which is modeled as a configuration pressure, is zero. Finally, results from a two sample problems involving shock-induced particle dispersion are presented. The results agree well with experimental measurements, providing initial confidence in the proposed model.« less

Recovery of organic acids

DOEpatents

Verser, Dan W.; Eggeman, Timothy J.

2009-10-13

A method is disclosed for the recovery of an organic acid from a dilute salt solution in which the cation of the salt forms an insoluble carbonate salt. A tertiary amine and CO.sub.2 are introduced to the solution to form the insoluble carbonate salt and a complex between the acid and an amine. A water immiscible solvent, such as an alcohol, is added to extract the acid/amine complex from the dilute salt solution to a reaction phase. The reaction phase is continuously dried and a product between the acid and the solvent, such as an ester, is formed.

Recovery of organic acids

DOEpatents

Verser, Dan W [Menlo Park, CA; Eggeman, Timothy J [Lakewood, CO

2011-11-01

A method is disclosed for the recovery of an organic acid from a dilute salt solution in which the cation of the salt forms an insoluble carbonate salt. A tertiary amine and CO.sub.2 are introduced to the solution to form the insoluble carbonate salt and a complex between the acid and an amine. A water immiscible solvent, such as an alcohol, is added to extract the acid/amine complex from the dilute salt solution to a reaction phase. The reaction phase is continuously dried and a product between the acid and the solvent, such as an ester, is formed.

Two-phase pressure drop reduction BWR assembly design

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

Dix, G.E.; Crowther, R.L.; Colby, M.J.

1992-05-12

This patent describes a boiling water reactor having discrete bundles of fuel rods confined within channel enclosed fuel assemblies, an improvement to a fuel bundle assembly for placement in the reactor. It comprises a fuel channel having vertically extending walls forming a continuous channel around a fuel assembly volume, the channel being open at the bottom end for engagement to a lower tie plate and open at the upper end for engagement to an upper tie plate; rods for placement within the chamber, each the rod containing fissile material for producing nuclear reaction when in the presence of sufficient moderatedmore » neutron flux; a lower tie plate for supporting the bundle of rods within the channel, the lower tie plate for supporting the bundle of rods within the channel, the lower tie plate joining the bottom of the channel to close the bottom end of the channel, the lower tie plate providing defined apertures for the inflow of water in the channel between the rods for the generating of steam during the nuclear reaction; the plurality of fuel rods extending from the lower tie plate wherein a single phase region of the water in the bundle is defined to an upward portion of the bundle wherein a two phase region of the water and steam in the bundle is defined during nuclear steam generating reaction in the fuel bundle.« less

The behaviour of tributyl phosphate in an organic diluent

NASA Astrophysics Data System (ADS)

Leay, Laura; Tucker, Kate; Del Regno, Annalaura; Schroeder, Sven L. M.; Sharrad, Clint A.; Masters, Andrew J.

2014-09-01

Tributyl phosphate (TBP) is used as a complexing agent in the Plutonium Uranium Extraction (PUREX) liquid-liquid phase extraction process for recovering uranium and plutonium from spent nuclear reactor fuel. Here, we address the molecular and microstructure of the organic phases involved in the extraction process, using molecular dynamics to show that when TBP is mixed with a paraffinic diluent, the TBP self-assembles into a bi-continuous phase. The underlying self-association of TBP is driven by intermolecular interaction between its polar groups, resulting in butyl moieties radiating out into the organic solvent. Simulation predicts a TBP diffusion constant that is anomalously low compared to what might normally be expected for its size; experimental nuclear magnetic resonance (NMR) studies also indicate an extremely low diffusion constant, consistent with a molecular aggregation model. Simulation of TBP at an oil/water interface shows the formation of a bilayer system at low TBP concentrations. At higher concentrations, a bulk bi-continuous structure is observed linking to this surface bilayer. We suggest that this structure may be intimately connected with the surprisingly rapid kinetics of the interfacial mass transport of uranium and plutonium from the aqueous to the organic phase in the PUREX process.

Alginate as immobilization matrix and stabilizing agent in a two-phase liquid system: application in lipase-catalysed reactions.

PubMed

Hertzberg, S; Kvittingen, L; Anthonsen, T; Skjåk-Braek, G

1992-01-01

Alginate was evaluated as an immobilization matrix for enzyme-catalyzed reactions in organic solvents. In contrast to most hydrogels, calcium alginate was found to be stable in a range of organic solvents and to retain the enzyme inside the gel matrix. In hydrophobic solvents, the alginate gel (greater than 95% water) thus provided a stable, two-phase liquid system. The lipase from Candida cylindracea, after immobilization in alginate beads, catalysed esterification and transesterification in n-hexane under both batch and continuous-flow conditions. The operational stability of the lipase was markedly enhanced by alginate entrapment. In the esterification of butanoic acid with n-butanol, better results were obtained in the typical hydrophilic calcium alginate beads than in less hydrophilic matrices. The effects of substrate concentration, matrix area, and polarity of the substrate alcohols and of the organic solvent on the esterification activity were examined. The transesterification of octyl 2-bromopropanoate with ethanol was less efficient than that of ethyl 2-bromopropanoate with octanol. By using the hydrophilic alginate gel as an immobilization matrix in combination with a mobile hydrophobic phase, a two-phase liquid system was achieved with definite advantages for a continuous, enzyme-catalysed process.

Ferrofluid-in-oil two-phase flow patterns in a flow-focusing microchannel

NASA Astrophysics Data System (ADS)

Sheu, T. S.; Chen, Y. T.; Lih, F. L.; Miao, J. M.

This study investigates the two-phase flow formation process of water-based Fe3O4 ferrofluid (dispersed phase) in a silicon oil (continuous phase) flow in the microfluidic flow-focusing microchannel under various operational conditions. With transparent PDMS chip and optical microscope, four main two-phase flow patterns as droplet flow, slug flow, ring flow and churn flow are observed. The droplet shape, size, and formation mechanism were also investigated under different Ca numbers and intended to find out the empirical relations. The paper marks an original flow pattern map of the ferrofluid-in-oil flows in the microfluidic flow-focusing microchannels. The flow pattern transiting from droplet flow to slug flow appears for an operational conditions of QR < 1 and Lf / W < 1. The power law index that related Lf / W to QR was 0.36 in present device.

Coal desulfurization by low temperature chlorinolysis, phase 2

NASA Technical Reports Server (NTRS)

Kalvinskas, J. J.; Grohmann, K.; Rohatgi, N.; Ernest, J.; Feller, D.

1980-01-01

An engineering scale reactor system was constructed and operated for the evaluation of five high sulfur bituminous coals obtained from Kentucky, Ohio, and Illinois. Forty-four test runs were conducted under conditions of 100 by 200 mesh coal,solvents - methlychloroform and water, 60 to 130 C, 0 to 60 psig, 45 to 90 minutes, and gaseous chlorine flow rate of up to 24 SCFH. Sulfur removals demonstrated for the five coals were: maximum total sulfur removal of 46 to 89% (4 of 5 coals with methylchloroform) and 0 to 24% with water. In addition, an integrated continuous flow mini-pilot plant was designed and constructed for a nominal coal rate of 2 kilograms/hour which will be operated as part of the follow-on program. Equipment flow sheets and design drawings are included for both the batch and continuous flow mini-pilot plants.

International Space Station Potable Water Characterization for 2013

NASA Technical Reports Server (NTRS)

Straub, John E., II; Plumlee, Debrah K.; Schultz, John R.; Mudgett, Paul D.

2014-01-01

In this post-construction, operational phase of International Space Station (ISS) with an ever-increasing emphasis on its use as a test-bed for future exploration missions, the ISS crews continue to rely on water reclamation systems for the majority of their water needs. The onboard water supplies include U.S. Segment potable water from humidity condensate and urine, Russian Segment potable water from condensate, and ground-supplied potable water, as reserve. In 2013, the cargo returned on the Soyuz 32-35 flights included archival potable water samples collected from Expeditions 34-37. The former Water and Food Analytical Laboratory (now Toxicology and Evironmental Chemistry Laboratory) at the NASA Johnson Space Center continued its long-standing role of performing chemical analyses on ISS return water samples to verify compliance with potable water quality specifications. This paper presents and discusses the analytical results for potable water samples returned from Expeditions 34-37, including a comparison to ISS quality standards. During the summer of 2013, the U.S. Segment potable water experienced a third temporary rise and fall in total organic carbon (TOC) content, as the result of organic contamination breaking through the water system's treatment process. Analytical results for the Expedition 36 archival samples returned on Soyuz 34 confirmed that dimethylsilanediol was once again the responsible contaminant, just as it was for the previous comparable TOC rises in 2010 and 2012. Discussion herein includes the use of the in-flight total organic carbon analyzer (TOCA) as a key monitoring tool for tracking these TOC rises and scheduling appropriate remediation.

Treatment of metal-laden hazardous wastes with advanced clean coal technology by-products. Quarterly report, December 30, 1996--March 30, 1997

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

NONE

1997-12-31

The objective of this project is to utilize coal ashes to process hazardous materials such as industrial waste water treatment residues, contaminated soils, and air pollution control dusts from the metal industry and municipal waste incineration. This report describes the activities of the project team during the reporting period. The principal work has focused upon continuing evaluation of aged samples from Phase 1, planning supportive laboratory studies for Phase 2, completing scholarly work, reestablishing MAX Environmental Technologies, Inc., as the subcontractor for the field work of Phase 2, proposing two presentations for later in 1997, and making and responding tomore » several outside contacts.« less

Prospecting Rovers for Lunar Exploration

NASA Technical Reports Server (NTRS)

Graham, Jerry B.; Vaughn, Jason A.; Farmer, Jeffery T.

2007-01-01

A study of lunar rover options for exploring the permanently shadowed regions of the lunar environment is presented. The potential for nearly continuous solar illumination coupled with the potential for water ice, focus exploration planner's attention on the polar regions of the moon. These regions feature craters that scientists have reason to believe may contain water ice. Water ice can be easily converted to fuel cell reactants, breathing oxygen, potable water, and rocket propellant. For these reasons, the NASA Robotic Lunar Exploration Program (RLEP) sponsored a study of potential prospecting rover concepts as one part of the RLEP-2 Pre-Phase A. Numerous vehicle configurations and power, thermal, and communication options are investigated. Rover options in the 400kg to 530kg class are developed which are capable of either confirming the presence of water ice at the poles, or conclusively demonstrating its absence.

Water vapor diffusion membrane development. [for water recovery purposes onboard manned spacecraft

NASA Technical Reports Server (NTRS)

Tan, M. K.

1974-01-01

The phase separator component used as a membrane in the vapor diffusion process (VRD) for the recovery of potable water from urine on manned space missions of extended duration was investigated, with particular emphasis on cation-selective membranes because of their noted mechanical strength, superior resistance to acids, oxidants, and germicides, and their potential resistance to organic foulants. Two of the membranes were tested for 700 hours continuously, and were selected on the basis of criteria deemed important to an effective water reclamation system onboard spacecraft. The samples of urine were successfully processed by removing 93 percent of their water content in 70 hours using the selected membranes. Pretreatment with an acid-oxidant formulation improved product quality. Cation exchange membranes were shown to possess superior mechanical strength and chemical resistance, as compared to cellulosic membranes.

Modified sedimentation-dispersion model for solids in a three-phase slurry column

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

Smith, D.N.; Ruether, J.A.; Shah, Y.T.

1986-03-01

Solids distribution data for a three-phase, batch-fluidized slurry bubble column (SBC) are presented, using air as the gas phase, pure liquids and solutions as the liquid phase, and glass beads and carborundum catalyst powder as the solid phase. Solids distribution data for the three-phase SBC operated in a continuous mode of operation are also presented, using nitrogen as the gas phase, water as the liquid phase, and glass beads as the solid phase. A new model to provide a reasonable approach to predict solids concentration distributions for systems containing polydispersed solids is presented. The model is a modification of standardmore » sedimentation-dispersion model published earlier. Empirical correlations for prediction of hindered settling velocity and solids dispersion coefficient for systems containing polydispersed solids are presented. A new method of evaluating critical gas velocity (CGV) from concentrations of the sample withdrawn at the same port of the SBC is presented. Also presented is a new mapping for CGV which separates the two regimes in the SBC, namely, incomplete fluidization and complete fluidization.« less

Physical and material properties of an emulsion-based lipstick produced via a continuous process.

PubMed

Beri, A; Pichot, R; Norton, I T

2014-04-01

Water-in-oil emulsions in lipsticks could have the potential to improve moisturizing properties and deliver hydrophilic molecules to the lips. The aim of this work was to investigate the effect of a continuous process (scraped surface heat exchanger (SSHE) and pin stirrer (PS)) on the physical and material properties of an emulsion-based lipstick by altering the processing conditions of both the SSHE and PS. Emulsion formation was achieved using a SSHE and PS. Emulsions were analysed using nuclear magnetic resonance restricted diffusion (droplet size), texture analysis and rheology (mechanical properties). Results showed that a higher impeller rotational velocity (IRV) (1500 r.p.m.) and a lower exit temperature (52°C) produce the smallest droplets (~ 4 μm), due to greater disruptive forces and a higher viscosity of the continuous phase. The addition of a PS reduces the droplet size (14-6 μm) if the SSHE has a low IRV (500 r.p.m.), due to greater droplet disruption as the emulsion passes through the PS unit. Results also show that if the jacket temperature of a SSHE is 65°C, so that crystallization occurs in both process and post-production, droplets can be integrated into the network resulting in a stiffer wax network (G' - 0.12, in comparison to 0.02 MPa). This is due to small crystals creating a shell around water droplets which can form connections with the continuous network forming a structured network. The addition of a pin stirrer can disrupt a formed network reducing the stiffness of the emulsion (0.3-0.05 MPa). This work suggests the potential use of a continuous process in producing an emulsion-based lipstick, particularly when wax crystals are produced in the process. Future work should consider the moisturizing or lubricating properties of wax continuous emulsions and the release of hydrophilic compounds from the aqueous phase.

Ultrafast cavitation induced by an X-ray laser in water drops

NASA Astrophysics Data System (ADS)

Stan, Claudiu; Willmott, Philip; Stone, Howard; Koglin, Jason; Liang, Mengning; Aquila, Andrew; Robinson, Joseph; Gumerlock, Karl; Blaj, Gabriel; Sierra, Raymond; Boutet, Sebastien; Guillet, Serge; Curtis, Robin; Vetter, Sharon; Loos, Henrik; Turner, James; Decker, Franz-Josef

2016-11-01

Cavitation in pure water is determined by an intrinsic heterogeneous cavitation mechanism, which prevents in general the experimental generation of large tensions (negative pressures) in bulk liquid water. We developed an ultrafast decompression technique, based on the reflection of shock waves generated by an X-ray laser inside liquid drops, to stretch liquids to large negative pressures in a few nanoseconds. Using this method, we observed cavitation in liquid water at pressures below -100 MPa. These large tensions exceed significantly those achieved previously, mainly due to the ultrafast decompression. The decompression induced by shock waves generated by an X-ray laser is rapid enough to continue to stretch the liquid phase after the heterogeneous cavitation occurs in water, despite the rapid growth of cavitation nanobubbles. We developed a nucleation-and-growth hydrodynamic cavitation model that explains our results and estimates the concentration of heterogeneous cavitation nuclei in water.

Comparison of solid-phase and pore-water approaches for assessing the quality of marine and estuarine sediments

USGS Publications Warehouse

Carr, Robert Scott; Chapman, Duane C.

1992-01-01

As part of our continuing evaluation of the pore-water approach for assessing sediment quality, we made a series of side-by-side comparisons between the standard 10-day amphipod whole sediment test with the corophiid Grandidierella japonica and a suite of tests using pore water extracted from the same sediments. the pore-water tests evaluated were the sea urchin (Arbacia punctulata) sperm cell test and morphological development assay, the life-cycle test with the polychaete Dinophilus gyrociliatus, and acute exposures of red drum (Sciaenops ocellatus) embryo-larval stages. Sediment and surface microlayer samples were collected from contaminated sites. Whole-sediment, pore-water, and surface microlayer toxicity tests were performed. Pore-water toxicity tests were considerably more sensitive than the whole-sediment amphipod test, which is currently the most sensitive toxicity test now recommended for determining the acceptability of dredged material for open ocean disposal.

A fundamental study of gas formation and migration during leakage of stored carbon dioxide in subsurface formations

NASA Astrophysics Data System (ADS)

Sakaki, T.; Plampin, M. R.; Lassen, R. N.; Pawar, R. J.; Komatsu, M.; Jensen, K. H.; Illangasekare, T. H.

2011-12-01

Geologic sequestration of CO2 has received significant attention as a potential method for reducing the release of greenhouse gases into the atmosphere. Potential risk of leakage of the stored CO2 to the shallow zones of the subsurface is one of the critical issues that is needed to be addressed to design effective field storage systems. If a leak occurs, gaseous CO2 reaching shallow zones of the subsurface can potentially impact the surface and groundwater sources and vegetation. With a goal of developing models that can predict these impacts, a research study is underway to improve our understanding of the fundamental processes of gas-phase formation and multi-phase flow dynamics during CO2 migration in shallow porous media. The approach involves conducting a series of highly controlled experiments in soil columns and tanks to study the effects of soil properties, temperature, pressure gradients and heterogeneities on gas formation and migration. This paper presents the results from a set of column studies. A 3.6m long column was instrumented with 16 soil moisture sensors, 15 of which were capable of measuring electrical conductivity (EC) and temperature, eight water pressure, and two gas pressure sensors. The column was filled with test sands with known hydraulic and retention characteristics with predetermined packing configurations. Deionized water saturated with CO2 under ~0.3 kPa (roughly the same as the hydrostatic pressure at the bottom of the column) was injected at the bottom of the column using a peristaltic pump. Water and gas outflow at the top of the column were monitored continuously. The results, in general, showed that 1) gas phase formation can be triggered by multiple factors such as water pressure drop, temperature rise, and heterogeneity, 2) transition to gas phase tends to occur rather within a short period of time, 3) gas phase fraction was as high as ~40% so that gas flow was not via individual bubble movement but two-phase flow, 4) water outflow that was initially equal to the inflow rate increased when gas-phase started to form (i.e., water gets displaced), and 5) gas starts to flow upward after gas phase fraction stabilizes (i.e., buoyant force overcomes). These results suggest that the generation and migration processes of gas phase CO2 can be modelled as a traditional two-phase flow with source (when CO2 gas exsolved due to complex factors) as well as sink (when gas dissolved) terms. The experimental data will be used to develop and test the conceptual models that will guide the development of numerical simulators for applications involving CO2 storage and leakage.

Characterization of occurrence, sources and sinks of perfluoroalkyl and polyfluoroalkyl substances (PFASs) in a tropical urban catchment.

PubMed

Chen, Huiting; Reinhard, Martin; Nguyen, Tung Viet; You, Luhua; He, Yiliang; Gin, Karina Yew-Hoong

2017-08-01

Understanding the sources, occurrence and sinks of perfluoroalkyl and polyfluoroalkyl substances (PFASs) in the urban water cycle is important to protect and utilize local water resources. Concentrations of 22 target PFASs and general water quality parameters were determined monthly for a year in filtered water samples from five tributaries and three sampling stations of an urban water body. Of the 22 target PFASs, 17 PFASs were detected with a frequency >93% including PFCAs: C4-C12 perfluoroalkyl carboxylates, C4, C6, C8, and C10 perfluoroalkane sulfonates, perfluorooctane sulfonamides and perfluorooctane sulfonamide substances (FOSAMs), C10 perfluoroalkyl phosphonic acid (C10 PFPA), 6:2 fluorotelomer sulfonic acid (6:2 FTSA) and C8/C8 perfluoroalkyl phosphinic acid (C8/C8-PFPIA). The most abundant PFASs in water were PFBS (1.4-55 ng/L), PFBA (1.0-23 ng/L), PFOS (1.5-24 ng/L) and PFOA (2.0-21 ng/L). In the tributaries, PFNA concentrations ranged from 1.2 to 87.1 ng/L except in the May 2013 samples of two tributaries, which reached 520 and 260 ng/L. Total PFAS concentrations in the sediment samples ranged from 1.6 to 15 ng/g d.w. with EtFOSAA, PFDoA, PFOS and PFDA being the dominant species. Based on water and sediment data, two types of sources were inferred: one-time or intermittent point sources and continuous non-point sources. FOSAMs and PFOS released continually from non-point sources, C8/C8 PFPIA, PFDoA and PFUnA was released from point sources. The highly water soluble short-chain PFASs including PFBA, PFPeA and PFBS remained predominantly in the water column. The factors governing solution phase concentrations appear to be compound hydrophobicity and sorption to suspended particles. Correlation of the dissolved phase concentrations with precipitation data suggested stormwater was a significant source of PFBA, PFBS, PFUnA and PFDoA. Negative correlations with precipitation indicated sources feeding FOSAA and FOSA directly into the tributaries. Copyright © 2017 Elsevier Ltd. All rights reserved.

Production of sugarcane and tropical grasses as a renewable energy source. Second annual report, 1978-1979

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

Not Available

1979-01-01

Reseach continued on tropical grasses from Saccharum and related genera as sources of intensively-produced, solar-dried biomass. Categories of candidate grasses include short-, intermediate-, and long-rotation species. These categories are based on the time interval required for maximum dry matter production, and on future management requirements of energy crops for intensive co-production with food crop commodities. Year 1 studies at the greenhouse and field-plot levels were continued and broadened during Year 2. This included candidate screening, importation and quarantine of new clones, breeding, controlled nitrogen and water regimes, chemical growth control, tissue expansion and maturation control, seeding rates, harvest frequency, andmore » variable row spacing. Second-year studies were extended to the project's field-scale and mechanized-harvest phases. These include initial economic anayses for the short-rotation phases. These include initial economic analyses for the short-rotation category of candidate species.« less

Selective Permeating Properties of Butanol and Water through Polystyrene- b-polydimethylsiloxane- b-polystyrene Pervaporation Membranes

NASA Astrophysics Data System (ADS)

Shin, Chaeyoung; Baer, Zachary; Chen, X. Chelsea; Ozcam, A. Evren; Clark, Douglas; Balsara, Nitash

2015-03-01

Polystyrene- b-polydimethylsiloxane- b-polystyrene (SDS) membranes have been studied in butanol-water binary pervaporation experiments and pervaporation experiments integrated with viable fermentation broths. Polydimethylsiloxane has been widely known to be a suitable material for separating organic chemicals from aqueous solutions, and it thus provides a continuous matrix phase in SDS membranes for permeation of small molecules. The polystyrene block provides mechanical stability to maintain the membrane structure in the pervaporation membranes. We take advantage of these features to fabricate a thin and butanol-selective SDS membrane for in situ product removal in fermentation.

The development of coal-based technologies for Department of Defense facilities. Volume 1, Technical report. Semiannual technical progress report, September 28, 1994--March 27, 1995

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

Miller, B.G.; Bartley, D.A.; Hatcher, P.

1996-10-15

This program is being conducted as a cooperative agreement between the Consortium for Coal Water Mixture Technology and the U.S. Department of Energy. Activities this reporting period are summarized by phase. Phase I is nearly completed. During this reporting period, coal beneficiation/preparation studies, engineering designs and economics for retrofitting the Crane, Indiana boiler to fire coal-based fuels, and a 1,000-hour demonstration of dry, micronized coal were completed. In addition, a demonstration-scale micronized-coal water mixture (MCWM) preparation circuit was constructed and a 1,000-hour demonstration firing MCWM began. Work in Phase II focused on emissions reductions, coal beneficiation/preparation studies, and economic analysesmore » of coal use. Emissions reductions investigations involved literature surveys of NO{sub x}, SO{sub 2}, trace metals, volatile organic compounds, and fine particulate matter capture. In addition, vendors and engineering firms were contacted to identify the appropriate emissions technologies for the installation of commercial NO{sub x} and SO{sub 2} removal systems on the demonstration boiler. Information from the literature surveys and engineering firms will be used to identify, design, and install a control system(s). Work continued on the refinement and optimization of coal grinding and MCWM preparation procedures, and on the development of advanced processes for beneficiating high ash, high sulfur coals. Work also continued on determining the basic cost estimation of boiler retrofits, and evaluating environmental, regulatory, and regional economic impacts. In addition, the feasibility of technology adoption, and the public`s perception of the benefits and costs of coal usage was studied. A coal market analysis was completed. Work in Phase III focused on coal preparation studies, emissions reductions and economic analyses of coal use.« less

Electrokinetic coupling in unsaturated porous media.

PubMed

Revil, A; Linde, N; Cerepi, A; Jougnot, D; Matthäi, S; Finsterle, S

2007-09-01

We consider a charged porous material that is saturated by two fluid phases that are immiscible and continuous on the scale of a representative elementary volume. The wetting phase for the grains is water and the nonwetting phase is assumed to be an electrically insulating viscous fluid. We use a volume-averaging approach to derive the linear constitutive equations for the electrical current density as well as the seepage velocities of the wetting and nonwetting phases on the scale of a representative elementary volume. These macroscopic constitutive equations are obtained by volume-averaging Ampère's law together with the Nernst-Planck equation and the Stokes equations. The material properties entering the macroscopic constitutive equations are explicitly described as functions of the saturation of the water phase, the electrical formation factor, and parameters that describe the capillary pressure function, the relative permeability functions, and the variation of electrical conductivity with saturation. New equations are derived for the streaming potential and electro-osmosis coupling coefficients. A primary drainage and imbibition experiment is simulated numerically to demonstrate that the relative streaming potential coupling coefficient depends not only on the water saturation, but also on the material properties of the sample, as well as the saturation history. We also compare the predicted streaming potential coupling coefficients with experimental data from four dolomite core samples. Measurements on these samples include electrical conductivity, capillary pressure, the streaming potential coupling coefficient at various levels of saturation, and the permeability at saturation of the rock samples. We found very good agreement between these experimental data and the model predictions.

Control of ice chromatographic retention mechanism by changing temperature and dopant concentration.

PubMed

Tasaki, Yuiko; Okada, Tetsuo

2011-12-15

A liquid phase coexists with solid water ice in a typical binary system, such as NaCl-water, in the temperature range between the freezing point and the eutectic point (t(eu)) of the system. In ice chromatography with salt-doped ice as the stationary phase, both solid and liquid phase can contribute to solute retention in different fashions; that is, the solid ice surface acts as an adsorbent, while a solute can be partitioned into the liquid phase. Thus, both adsorption and partition mechanisms can be utilized for ice chromatographic separation. An important feature in this approach is that the liquid phase volume can be varied by changing the temperature and the concentration of a salt incorporated into the ice stationary phase. Thus, we can control the relative contribution from the partition mechanism in the entire retention because the liquid phase volume can be estimated from the freezing depression curve. Separation selectivity can thereby be modified. The applicability of this concept has been confirmed for the solutes of different adsorption and partition abilities. The predicted retention based on thermodynamics basically agrees well with the corresponding experimental retention. However, one important inconsistency has been found. The calculation predicts a step-like discontinuity of the solute retention at t(eu) because the phase diagram suggests that the liquid phase abruptly appears at t(eu) when the temperature increases. In contrast, the corresponding experimental plots are continuous over the wider range including the subeutectic temperatures. This discrepancy is explained by the existence of the liquid phase below t(eu). A difference between predicted and measured retention factors allows the estimation of the volume of the subeutectic liquid phase.

Ecological effects of nitrogen and sulfur air pollution in the US: what do we know?

USGS Publications Warehouse

Greaver, Tara L.; Sullivan, Timothy J.; Herrick, Jeffrey D.; Barber, Mary C.; Baron, Jill S.; Cosby, Bernard J.; Deerhake, Marion E.; Dennis, Robin L.; Dubois, Jean-Jacque B.; Goodale, Christine L.; Herlihy, Alan T.; Lawrence, Gregory B.; Liu, Lingli; Lynch, Jason A.; Novak, Kristopher J.

2012-01-01

Four decades after the passage of the US Clean Air Act, air-quality standards are set to protect ecosystems from damage caused by gas-phase nitrogen (N) and sulfur (S) compounds, but not from the deposition of these air pollutants to land and water. Here, we synthesize recent scientific literature on the ecological effects of N and S air pollution in the US. Deposition of N and S is the main driver of ecosystem acidification and contributes to nutrient enrichment in many natural systems. Although surface-water acidification has decreased in the US since 1990, it remains a problem in many regions. Perturbations to ecosystems caused by the nutrient effects of N deposition continue to emerge, although gas-phase concentrations are generally not high enough to cause phytotoxicity. In all, there is overwhelming evidence of a broad range of damaging effects to ecosystems in the US under current air quality conditions.

Phase behavior and kinetics of phase separation of a nonionic microemulsion of C12E5/water/1-chlorotetradecane upon a temperature quench.

PubMed

Roshan Deen, G; Oliveira, Cristiano L P; Pedersen, Jan Skov

2009-05-21

The phase behavior and phase separation kinetics of a model ternary nonionic microemulsion system composed of pentaethylene glycol dodecyl ether (C12E5), water, and 1-chlorotetradecane were studied. With increasing temperature, the microemulsion exhibits the following rich phase behavior: oil-in-water phase (L1+O), droplet microemulsion phase (L1), lamellar liquid crystalline phase (Lproportional), and sponge-like (liquid) phase (L3). The microemulsion with a fixed surfactant-to-oil volume fraction ratio (Phis/Phio) of 0.81 and droplet volume fraction of 0.087 was perturbed from equilibrium by a temperature quench from the L1 region (24 degrees C) to an unstable region L1+O (13 degrees C), where the excess oil phase is in equilibrium with the microemulsion droplets. The process of phase separation in the unstable region was followed by time-resolved small-angle X-ray scattering (TR-SAXS) and time-resolved turbidity methods. Due to the large range of scattering vector (q=0.004-0.22 A(-1)) that is possible to access with the TR-SAXS method, the growth of the oil droplets and shrinking of the microemulsion droplets as a result of phase separation could be studied simultaneously. By using an advanced polydisperse ellipsoidal hard-sphere model, the experimental curves have been quantitatively analyzed. The microemulsion droplets were modeled as polydisperse core-shell ellipsoidal particles, using molecular constraints, and the oil droplets are modeled as polydisperse spheres. The radius of gyration (Rg) of the growing oil droplets, volume fraction of oil in the microemulsion droplets, and polydispersity were obtained from the fit parameters. The volume equivalent radius at the neutral plane between the surfactant head and tail of the microemulsion droplet decreased from 76 to 51 A, while the radius of oil drop increased to 217 A within the 160 min of the experiment. After about 48 min from the temperature quench, the system reaches a steady state and continues to coarsen at a constant fraction of the oil of 0.51 in the oil phase by Ostwald ripening with the power law dependence of Roil proportional, variant t1/3. The size of the oil droplets determined by the time-resolved turbidity method is in good agreement with that of the TR-SAXS, highlighting the usefulness of the method in the size determination of oil-in-water microemulsions on an absolute scale.

Speciation of chromium using reversed phase-high performance liquid chromatography coupled to different spectrometric detection methods

NASA Astrophysics Data System (ADS)

Andrle, C. M.; Jakubowski, N.; Broekaert, J. A. C.

1997-02-01

Speciation of Cr(III) and Cr(VI) based on the formation of different complexes with ammonium-pyrrolidinedithioate (APDC) in a continuous flow technique and their preconcentration using solid phase extraction (SPE) have been elaborated and applied to the analysis of waste waters from the galvanic industry. The Cr complexes were separated and determined using reversed phase-high performance liquid chromatography (RP-HPLC) coupled to different detection methods, namely UV-detection, graphite furnace-atomic absorption spectrometry (GF-AAS) and inductively coupled plasma mass spectrometry with hydraulic high pressure nebulization (HHPN/ICP-MS). After optimization the detection limits for Cr(III) and Cr(VI) of all methods are at the μg 1 -1 level and the precision in terms of RSD is 5% ( cCr = 100 μg 1 -1, N = 10). The procedure was applied to the determination of Cr(III) and Cr(VI) at the μg 1 -1 level in galvanic waste waters, and its accuracy was approved by comparing the results with those of independent methods.

[Properties of synthesized CdS nanoparticles by reverse micelle method].

PubMed

Li, Heng-Da; Wang, Qing-Wei; Zhai, Hong-Ju; Li, Wen-Lian

2008-07-01

Micelle system with reverse phase (water/CTAB/n-hexyl alcohol/n-heptane) is a weenie liquid-globelet of surface active agent molecule which can be stably and uniformly dispersed in continuous oil medium. The micelle system with reverse phase can work as a "micro-reactor" to synthesize CdS nano-particle with excellent performance. In the present article considering the effects of W value (W= [water]/[surface agent]) of the micelle system with reverse phase, we observed that the ratio of [Cd2+] and [S2-] ions to the original concentrations of the Cd2+ and S2- ions can affect the luminescent properties of CdS nano-particle. Using regurgitant treatment process the surface of CdS nano-particle can be modified, and as a result the defect emission was reduced and even disappeared, but exciton emissions markedly increased. On the other hand, a red-shift of the exciton emission peak with the increase in the particle size was observed, indicating considerable quantum confinement effect. A maximum quantum efficiency of 11% for the synthesized CdS nano-material was achieved.

Water Based Phase Change Material Heat Exchanger Development

NASA Technical Reports Server (NTRS)

Hansen, Scott W.; Sheth, Ribik B.; Atwell, Matt; Cheek, Ann; Agarwal, Muskan; Hong, Steven; Patel, Aashini,; Nguyen, Lisa; Posada, Luciano

2014-01-01

In a cyclical heat load environment such as low Lunar orbit, a spacecraft’s radiators are not sized to reject the full heat load requirement. Traditionally, a supplemental heat rejection device (SHReD) such as an evaporator or sublimator is used to act as a “topper” to meet the additional heat rejection demands. Utilizing a Phase Change Material (PCM) heat exchanger (HX) as a SHReD provides an attractive alternative to evaporators and sublimators as PCM HXs do not use a consumable, thereby leading to reduced launch mass and volume requirements. Studies conducted in this paper investigate utilizing water’s high latent heat of formation as a PCM, as opposed to traditional waxes, and corresponding complications surrounding freezing water in an enclosed volume. Work highlighted in this study is primarily visual and includes understanding ice formation, freeze front propagation, and the solidification process of water/ice. Various test coupons were constructed of copper to emulate the interstitial pin configuration (to aid in conduction) of the proposed water PCM HX design. Construction of a prototypic HX was also completed in which a flexible bladder material and interstitial pin configurations were tested. Additionally, a microgravity flight was conducted where three copper test articles were frozen continuously during microgravity and 2-g periods and individual water droplets were frozen during microgravity.

In situ emulsification using a non-uniform alternating electric field

NASA Astrophysics Data System (ADS)

Choi, Suhwan; Saveliev, Alexei V.

2014-08-01

We report an electric field based method for in situ emulsification of water droplets immersed in a continuous oil phase. High density water-in-oil emulsions are generated using non-uniform ac electric fields applied between needle and plate electrodes. An initial water droplet is entrained in the area of high electric field near the needle electrode where it is dispersed under the influence of high electric stresses. Breakup mechanisms responsible for a gradual dispersion of the water droplets are investigated. Identified mechanisms involve drop elongation to a cylindrical shape followed by a capillary breakup, ac electrospraying from individual water droplets, and formation and breakup of bead-like structures comprised by the water droplets interconnected by thin water bridges. Water droplets with diameters close to 1 μm and a narrow size distribution are formed at long processing times. The generated emulsion has a well-defined boundary and is confined near the needle electrode in a shape resembling a pendant drop.

Quantitative aspects of vibratory mobilization and break-up of non-wetting fluids in porous media

NASA Astrophysics Data System (ADS)

Deng, Wen

Seismic stimulation is a promising technology aimed to mobilize the entrapped non-wetting fluids in the subsurface. The applications include enhanced oil recovery or, alternatively, facilitation of movement of immiscible/partly-miscible gases far into porous media, for example, for CO2 sequestration. This work is devoted to detailed quantitative studies of the two basic pore-scale mechanisms standing behind seismic stimulation: the mobilization of bubbles or drops entrapped in pore constrictions by capillary forces and the break-up of continuous long bubbles or drops. In typical oil-production operations, oil is produced by the natural reservoir-pressure drive during the primary stage and by artificial water flooding at the secondary stage. Capillary forces act to retain a substantial residual fraction of reservoir oil even after water flooding. The seismic stimulation is an unconventional technology that serves to overcome capillary barriers in individual pores and liberate the entrapped oil by adding an oscillatory inertial forcing to the external pressure gradient. According to our study, the effect of seismic stimulation on oil mobilization is highly dependent on the frequencies and amplitudes of the seismic waves. Generally, the lower the frequency and the larger the amplitude, more effective is the mobilization. To describe the mobilization process, we developed two theoretical hydrodynamics-based models and justified both using computational fluid dynamics (CFD). Our theoretical models have a significant advantage over CFD in that they reduce the computational time significantly, while providing correct practical guidance regarding the required field parameters of vibroseismic stimulation, such as the amplitude and frequency of the seismic field. The models also provide important insights into the basic mechanisms governing the vibration-driven two-phase flow in constricted capillaries. In a waterflooded reservoir, oil can be recovered most efficiently by forming continuous streams from isolated droplets. The longer the continuous oil phase under a certain pressure gradient, the more easily it overcomes its capillary barrier. However, surface tension between water and oil causes the typically non-wetting oil, constituting the core phase in the channels, to break up at the pore constriction into isolated beads, which inhibits further motion. The break-up thus counteracts the mobilization. We developed a theoretical model that provides an exact quantitative description of the dynamics of the oil-snap-off process. It also formulates a purely geometric criterion that controls, based on pore geometry only, whether the oil core phase stays continuous or disintegrates into droplets. Both the theoretical model and the break-criterion have been validated against CFD simulations. The work completed elucidates the basic physical mechanisms behind the enhanced oil recovery by seismic waves and vibrations. This creates a theoretical foundation for the further development of corresponding field technologies.

Trace analysis of endocrine disrupting compounds in environmental water samples by use of solid-phase extraction and gas chromatography with mass spectrometry detection.

PubMed

Azzouz, Abdelmonaim; Ballesteros, Evaristo

2014-09-19

A novel analytical method using a continuous solid-phase extraction system in combination with gas chromatography-mass spectrometry for the simultaneous separation and determination of endocrine disrupting compounds (EDCs) is reported. The method was applied to major EDCs of various types including parabens, alkylphenols, phenylphenols, bisphenol A and triclosan in water. Samples were preconcentrated by using an automatic solid-phase extraction module containing a sorbent column, and retained analytes eluted with acetonitrile for derivatization with a mixture of N,O-bis(trimethylsilyl)trifluoroacetamide and trimethylchlorosilane. A number of variables potentially influencing recovery of the target compounds such as the type of SPE sorbent (Silica gel, Florisil, RP-C18, Amberlite XAD-2 and XAD-4, Oasis HLB and LiChrolut EN), eluent and properties of the water including pH and ionic strength, were examined. LiChrolut EN was found to be the most efficient sorbent for retaining the analytes, with ∼100% efficiency. The ensuing method was validated with good analytical results including low limits of detection (0.01-0.08ng/L for 100mL of sample) and good linearity (r(2)>0.997) throughout the studied concentration ranges. The method exhibited good accuracy (recoveries of 90-101%) and precision (relative standard deviations less than 7%) in the determination of EDCs in drinking, river, pond, well, swimming pool and waste water. Waste water samples were found to contain the largest number and highest concentrations of analytes (3.2-390ng/L). Copyright © 2014 Elsevier B.V. All rights reserved.

Numerical modeling of the waves evolution generated by the depressurization of the vessels containing a supercritical parameters coolant

NASA Astrophysics Data System (ADS)

Alekseev, Maksim V.; Vozhakov, Ivan S.; Lezhnin, Sergey I.; Pribaturin, Nikolay A.

2017-10-01

The development of power plants focuses on increasing the parameters of water coolants up to a supercritical level. Depressurization of the unit circuits with such a coolant leads to emergency situations. Their scenarios can change significantly with the variation of initial pressure and temperature before the start of depressurization. When the pressure drops from the supercritical single-phase region of the initial thermodynamic parameters of the coolant, either the liquid boils up, or the vapor is condensed. Because of the rapid pressure decrease, the phase transition can be non-equilibrium that must be taken into account in the simulation. In the present study, an axisymmetric problem of the outflow of a water coolant from the pipe butt-end is considered. The equations of continuity, momentum and energy for a two-phase homogeneous mixture are solved numerically. The vapor and liquid properties are calculated using the TTSE software package (The Tabular Taylor Series Expansion Method). On the basis of the computer complex LCPFCT (The Flux-Corrected Transport Algorithm) the program code was developed for solving numerous problems on the depressurization of vessels or pipelines, containing superheated water or gas under high pressure. Different variants of outflow in the external model atmosphere and generation of waves are analyzed. The calculated data on the interaction of pressure waves with a barrier are calculated. To describe phase transitions, an asymptotic relaxation model of nonequilibrium evaporation and condensation has been created and tested.

A Science Plan for a Comprehensive Regional Assessment of the Atlantic Coastal Plain Aquifer System in Maryland

USGS Publications Warehouse

Shedlock, Robert J.; Bolton, David W.; Cleaves, Emery T.; Gerhart, James M.; Nardi, Mark R.

2007-01-01

The Maryland Coastal Plain region is, at present, largely dependent upon ground water for its water supply. Decades of increasing pumpage have caused ground-water levels in parts of the Maryland Coastal Plain to decline by as much as 2 feet per year in some areas of southern Maryland. Continued declines at this rate could affect the long-term sustainability of ground-water resources in Maryland's heavily populated Coastal Plain communities and the agricultural industry of the Eastern Shore. In response to a recommendation in 2004 by the Advisory Committee on the Management and Protection of the State's Water Resources, the Maryland Geological Survey and the U.S. Geological Survey have developed a science plan for a comprehensive assessment that will provide new scientific information and new data management and analysis tools for the State to use in allocating ground water in the Coastal Plain. The comprehensive assessment has five goals aimed at improving the current information and tools used to understand the resource potential of the aquifer system: (1) document the geologic and hydrologic characteristics of the aquifer system in the Maryland Coastal Plain and appropriate areas of adjacent states; (2) conduct detailed studies of the regional ground-water-flow system and water budget for the aquifer system; (3) improve documentation of patterns of water quality in all Coastal Plain aquifers, including the distribution of saltwater; (4) enhance ground-water-level, streamflow, and water-quality-monitoring networks in the Maryland Coastal Plain; and (5) develop science-based tools to facilitate sound management of the ground-water resources in the Maryland Coastal Plain. The assessment, as designed, will be conducted in three phases and if fully implemented, is expected to take 7 to 8 years to complete. Phase I, which was initiated in January 2006, is an effort to assemble all the information and investigation tools needed to do a more comprehensive assessment of the aquifer system. The work will include updating the hydrogeologic framework, developing a Geographic Information System-based aquifer information system, refinement of water-use information, assessment of existing water-quality data, and development of detailed plans for ground-water-flow and management models. Phase II is an intensive study phase during which a regional ground-water-flow model will be developed and calibrated for the entire region of Maryland in the Atlantic Coastal Plain as well as appropriate areas of Delaware and Virginia. The model will be used to simulate flow and water levels in the aquifer system and to study the water budget of the system. The model analysis will be based on published information but will be supplemented with field investigations of recharge and leakage in the aquifer system. Localized and finely discretized ground-water-flow models that are embedded in the regional model will be developed for selected areas of heavy withdrawals. Other modeling studies will be conducted to better understand flow in the unconfined parts of the aquifer system and to support the recharge studies. Phase II will also include selected water-quality studies and a study to determine how hydrologic and water-quality-monitoring networks need to be enhanced to appropriately assess the sustainability of the Coastal Plain aquifer system. Phase III will be largely devoted to the development and application of a ground-water optimization model. This model will be linked to the ground-water-flow model to create a model package that can be used to test different water-management scenarios. The management criteria that will be used to develop these scenarios will be determined in consultation with a variety of state and local stakeholders and policy makers in Phases I and II of the assessment. The development of the aquifer information system is a key component of the assessment. The system will store all relevant aquifer data

Electrical power generation by mechanically modulating electrical double layers.

PubMed

Moon, Jong Kyun; Jeong, Jaeki; Lee, Dongyun; Pak, Hyuk Kyu

2013-01-01

Since Michael Faraday and Joseph Henry made their great discovery of electromagnetic induction, there have been continuous developments in electrical power generation. Most people today get electricity from thermal, hydroelectric, or nuclear power generation systems, which use this electromagnetic induction phenomenon. Here we propose a new method for electrical power generation, without using electromagnetic induction, by mechanically modulating the electrical double layers at the interfacial areas of a water bridge between two conducting plates. We find that when the height of the water bridge is mechanically modulated, the electrical double layer capacitors formed on the two interfacial areas are continuously charged and discharged at different phases from each other, thus generating an AC electric current across the plates. We use a resistor-capacitor circuit model to explain the results of this experiment. This observation could be useful for constructing a micro-fluidic power generation system in the near future.

A Robust Oil-in-Oil Emulsion for the Nonaqueous Encapsulation of Hydrophilic Payloads.

PubMed

Lu, Xiaocun; Katz, Joshua S; Schmitt, Adam K; Moore, Jeffrey S

2018-03-14

Compartmentalized structures widely exist in cellular systems (organelles) and perform essential functions in smart composite materials (microcapsules, vasculatures, and micelles) to provide localized functionality and enhance materials' compatibility. An entirely water-free compartmentalization system is of significant value to the materials community as nonaqueous conditions are critical to packaging microcapsules with water-free hydrophilic payloads while avoiding energy-intensive drying steps. Few nonaqueous encapsulation techniques are known, especially when considering just the scalable processes that operate in batch mode. Herein, we report a robust oil-in-oil Pickering emulsion system that is compatible with nonaqueous interfacial reactions as required for encapsulation of hydrophilic payloads. A major conceptual advance of this work is the notion of the partitioning inhibitor-a chemical agent that greatly reduces the payload's distribution between the emulsion's two phases, thus providing appropriate conditions for emulsion-templated interfacial polymerization. As a specific example, an immiscible hydrocarbon-amine pair of liquids is emulsified by the incorporation of guanidinium chloride (GuHCl) as a partitioning inhibitor into the dispersed phase. Polyisobutylene (PIB) is added into the continuous phase as a viscosity modifier for suitable modification of interfacial polymerization kinetics. The combination of GuHCl and PIB is necessary to yield a robust emulsion with stable morphology for 3 weeks. Shell wall formation was accomplished by interfacial polymerization of isocyanates delivered through the continuous phase and polyamines from the droplet core. Diethylenetriamine (DETA)-loaded microcapsules were isolated in good yield, exhibiting high thermal and chemical stabilities with extended shelf-lives even when dispersed into a reactive epoxy resin. The polyamine phase is compatible with a variety of basic and hydrophilic actives, suggesting that this encapsulation technology is applicable to other hydrophilic payloads such as polyols, aromatic amines, and aromatic heterocyclic bases. Such payloads are important for the development of extended pot or shelf life systems and responsive coatings that report, protect, modify, and heal themselves without intervention.

Membrane-aerated biofilm reactor for the removal of 1,2-dichloroethane by Pseudomonas sp. strain DCA1.

PubMed

Hage, J C; Van Houten, R T; Tramper, J; Hartmans, S

2004-06-01

A membrane-aerated biofilm reactor (MBR) with a biofilm of Pseudomonas sp. strain DCA1 was studied for the removal of 1,2-dichloroethane (DCA) from water. A hydrophobic membrane was used to create a barrier between the liquid and the gas phase. Inoculation of the MBR with cells of strain DCA1 grown in a continuous culture resulted in the formation of a stable and active DCA-degrading biofilm on the membrane. The maximum removal rate of the MBR was reached at a DCA concentration of approximately 80 micro M. Simulation of the DCA fluxes into the biofilm showed that the MBR performance at lower concentrations was limited by the DCA diffusion rate rather than by kinetic constraints of strain DCA1. Aerobic biodegradation of DCA present in anoxic water could be achieved by supplying oxygen solely from the gas phase to the biofilm grown on the liquid side of the membrane. As a result, direct aeration of the water, which leads to undesired coagulation of iron oxides, could be avoided.

Solid-phase microextraction-gas chromatography-mass spectrometry for the analysis of selective serotonin reuptake inhibitors in environmental water.

PubMed

Lamas, J Pablo; Salgado-Petinal, Carmen; García-Jares, Carmen; Llompart, María; Cela, Rafael; Gómez, Mariano

2004-08-13

The continuous contamination of surface waters by pharmaceuticals is of most environmental concern. Selective serotonin reuptake inhibitors (SSRIs) are drugs currently prescribed for the treatment of depressions and other psychiatric disorders and then, they are among the pharmaceuticals that can occur in environmental waters. Solid-phase microextraction (SPME) coupled to gas chromatography-mass spectrometry has been applied to the extraction of five SSRIs--venlafaxine, fluvoxamine, fluoxetine, citalopram and sertraline--from water samples. Some of the analytes were not efficiently extracted as underivatized compounds and so, an in situ acetylation step was introduced in the sample preparation procedure. Different parameters affecting extraction efficiency such as extraction mode, fiber coating and temperature were studied. A mixed-level fractional factorial design was also performed to simultaneously study the influence of other five experimental factors. Finally, a method based on direct SPME at 100 degrees C using polydimethylsiloxane-divinylbenzene fibers is proposed. The performance of the method was evaluated, showing good linearity and precision. The detection limits were in the sub-ng/mL level. Practical applicability was demonstrated through the analysis of real samples. Recoveries obtained for river water and wastewater samples were satisfactory in all cases. An important aspect of the proposed method is that no matrix effects were observed. Two of the target compounds, venlafaxine and citalopram, were detected and quantified in a sewage water sample.

The U.S. Gas Flooding Experience: CO2 Injection Strategies and Impact on Ultimate Recovery

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

Nunez-Lopez, Vanessa; Hosseini, Seyyed; Gil-Egui, Ramon

The Permian Basin in West Texas and southwestern New Mexico has seen 45 years of oil reserve growth through CO2 enhanced oil recovery (CO2 EOR). More than 60 CO2 EOR projects are currently active in the region’s limestone, sandstone and dolomite reservoirs. Water alternating gas (WAG) has been the development strategy of choice in the Permian for several technical and economic reasons. More recently, the technology started to get implemented in the much more porous and permeable clastic depositional systems of the onshore U.S. Gulf Coast. Continued CO2 injection (CGI), as opposed to WAG, was selected as the injection strategymore » to develop Gulf Coast oil fields, where CO2 injection volumes are significantly larger (up to 6 times larger) than those of the Permian. We conducted a compositional simulation based study with the objective of comparing the CO2 utilization ratios (volume of CO2 injected to produce a barrel of oil) of 4 conventional and novel CO2 injection strategies: (1) continuous gas injection (CGI), (2) water alternating gas (WAG), (3) water curtain injection (WCI), and (4) WAG and WCI combination. These injection scenarios were simulated using the GEM module from the Computer Modeling Group (CMG). GEM is an advanced general equation-of-state compositional simulator, which includes equation of state, CO2 miscible flood, CO2/brine interactions, and complex phase behavior. The simulator is set up to model three fluid phases including water, oil, and gas. Our study demonstrates how the selected field development strategy has a significant impact on the ultimate recovery of CO2-EOR projects, with GCI injection providing maximum oil recovery in absolute volume terms, but with WAG offering a more balanced technical-economical approach.« less

Early Dynamics and Stabilization Mechanisms of Oil-in-Water Emulsions Containing Colloidal Particles Modified with Short Amphiphiles: A Numerical Study.

PubMed

Cerbelaud, Manuella; Videcoq, Arnaud; Alison, Lauriane; Tervoort, Elena; Studart, André R

2017-12-19

Emulsions stabilized by mixtures of particles and amphiphilic molecules are relevant for a wide range of applications, but their dynamics and stabilization mechanisms on the colloidal level are poorly understood. Given the challenges to experimentally probe the early dynamics and mechanisms of droplet stabilization, Brownian dynamics simulations are developed here to study the behavior of oil-in-water emulsions stabilized by colloidal particles modified with short amphiphiles. Simulation parameters are based on an experimental system that consists of emulsions obtained with octane as the oil phase and a suspension of alumina colloidal particles modified with short carboxylic acids as the continuous aqueous medium. The numerical results show that attractive forces between the colloidal particles favor the formation of closely packed clusters on the droplet surface or of a percolating network of particles throughout the continuous phase, depending on the amphiphile concentration. Simulations also reveal the importance of a strong adsorption of particles at the liquid interface to prevent their depletion from the droplet surface when another droplet approaches. Strongly adsorbed particles remain immobile on the droplet surface, generating an effective steric barrier against droplet coalescence. These findings provide new insights into the early dynamics and mechanisms of stabilization of emulsions using particles and amphiphilic molecules.

Observations of open-ocean deep convection in the northwestern Mediterranean Sea: Seasonal and interannual variability of mixing and deep water masses for the 2007-2013 Period

NASA Astrophysics Data System (ADS)

Houpert, L.; Durrieu de Madron, X.; Testor, P.; Bosse, A.; D'Ortenzio, F.; Bouin, M. N.; Dausse, D.; Le Goff, H.; Kunesch, S.; Labaste, M.; Coppola, L.; Mortier, L.; Raimbault, P.

2016-11-01

We present here a unique oceanographic and meteorological data set focus on the deep convection processes. Our results are essentially based on in situ data (mooring, research vessel, glider, and profiling float) collected from a multiplatform and integrated monitoring system (MOOSE: Mediterranean Ocean Observing System on Environment), which monitored continuously the northwestern Mediterranean Sea since 2007, and in particular high-frequency potential temperature, salinity, and current measurements from the mooring LION located within the convection region. From 2009 to 2013, the mixed layer depth reaches the seabed, at a depth of 2330m, in February. Then, the violent vertical mixing of the whole water column lasts between 9 and 12 days setting up the characteristics of the newly formed deep water. Each deep convection winter formed a new warmer and saltier "vintage" of deep water. These sudden inputs of salt and heat in the deep ocean are responsible for trends in salinity (3.3 ± 0.2 × 10-3/yr) and potential temperature (3.2 ± 0.5 × 10-3 C/yr) observed from 2009 to 2013 for the 600-2300 m layer. For the first time, the overlapping of the three "phases" of deep convection can be observed, with secondary vertical mixing events (2-4 days) after the beginning of the restratification phase, and the restratification/spreading phase still active at the beginning of the following deep convection event.

Studies of cavitation and ice nucleation in 'doubly-metastable' water: time-lapse photography and neutron diffraction.

PubMed

Barrow, Matthew S; Williams, P Rhodri; Chan, Hoi-Houng; Dore, John C; Bellissent-Funel, Marie-Claire

2012-10-14

High-speed photographic studies and neutron diffraction measurements have been made of water under tension in a Berthelot tube. Liquid water was cooled below the normal ice-nucleation temperature and was in a doubly-metastable state prior to a collapse of the liquid state. This transition was accompanied by an exothermic heat release corresponding with the rapid production of a solid phase nucleated by cavitation. Photographic techniques have been used to observe the phase transition over short time scales in which a solidification front is observed to propagate through the sample. Significantly, other images at a shorter time interval reveal the prior formation of cavitation bubbles at the beginning of the process. The ice-nucleation process is explained in terms of a mechanism involving hydrodynamically-induced changes in tension in supercooled water in the near vicinity of an expanding cavitation bubble. Previous explanations have attributed the nucleation of the solid phase to the production of high positive pressures. Corresponding results are presented which show the initial neutron diffraction pattern after ice-nucleation. The observed pattern does not exhibit the usual crystalline pattern of hexagonal ice [I(h)] that is formed under ambient conditions, but indicates the presence of other ice forms. The composite features can be attributed to a mixture of amorphous ice, ice-I(h)/I(c) and the high-pressure form, ice-III, and the diffraction pattern continues to evolve over a time period of about an hour.

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.

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.

Carbon isotope analysis of dissolved organic carbon in fresh and saline (NaCl) water via continuous flow cavity ring-down spectroscopy following wet chemical oxidation

USGS Publications Warehouse

Conaway, Christopher; Thomas, Randal B.; Saad, Nabil; Thordsen, James J.; Kharaka, Yousif K.

2015-01-01

This work examines the performance and limitations of a wet chemical oxidation carbon analyser interfaced with a cavity ring-down spectrometer (WCO-CRDS) in a continuous flow (CF) configuration for measuring δ13C of dissolved organic carbon (δ13C-DOC) in natural water samples. Low-chloride matrix (<5 g Cl/L) DOC solutions were analysed with as little as 2.5 mg C/L in a 9 mL aliquot with a precision of 0.5 ‰. In high-chloride matrix (10–100 g Cl/L) DOC solutions, bias towards lighter δ13C-DOC was observed because of incomplete oxidation despite using high-concentration oxidant, extended reaction time, or post-wet chemical oxidation gas-phase combustion. However, through a combination of dilution, chloride removal, and increasing the oxidant:sample ratio, high-salinity samples with sufficient DOC (>22.5 µg C/aliquot) may be analysed. The WCO-CRDS approach requires more total carbon (µg C/aliquot) than conventional CF-isotope ratio mass spectrometer, but is nonetheless applicable to a wide range of DOC concentration and water types, including brackish water, produced water, and basinal brines.

Amelogenin Affects Brushite Crystal Morphology and Promotes Its Phase Transformation to Monetite

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

Ren, Dongni; Ruan, Qichao; Tao, Jinhui

2016-09-07

Amelogenin protein is involved in organized apatite crystallization during enamel formation. Brushite (CaHPO4·2H2O), which is one of the precursors for hydroxyapatite in in vitro mineralization, has been used for fabrication of biomaterials for hard tissue repair. In order to explore its potential application in biomimetic material synthesis, we studied the influence of amelogenin on brushite morphology and phase transformation to monetite. Our results show that amelogenin can adsorb onto surface of brushite, leading to the formation of layered structures on the (010) face. Amelogenin promoted the phase transformation of brushite into monetite (CaHPO4) in the dry state, presumably by interactingmore » with crystalline water layers in brushite unit cell. Changes to the crystal morphology by amelogenin continued even after the phase transformation to monetite forming an organized nanotextured structure of nano-sticks resembling the bundle structure in enamel.« less

Inter- annual variability of water vapor over an equatorial coastal station using Microwave Radiometer observations.

NASA Astrophysics Data System (ADS)

Renju, Ramachandran Pillai; Uma, K. N.; Krishna Moorthy, K.; Mathew, Nizy; Raju C, Suresh

The south-western region of the Indian peninsula is the gateway of Indian summer monsoon. This region experiences continuous monsoon rain for a longer period of about six months from June to November. The amount of water vapor variability is one of the important parameters to study the onset, active and break phases of the monsoon. Keeping this in view, a multi-frequency Microwave Radiometer Profiler (MRP) has been made operational for continuous measurements of water vapor over an equatorial coastal station Thiruvananthapuram (8.5(°) N, 76.9(°) E) since April 2010. The MRP estimated precipitable water vapor (PWV) for different seasons including monsoon periods have been evaluated by comparing with the collocated GPS derived water vapor and radiosonde measurements. The diurnal, seasonal and inter annual variation of water vapor has been studied for the last four years (2010-2013) over this station. The significant diurnal variability of water vapor is found only during the winter and pre-monsoon periods (Dec -April). The vertical distribution of water vapour is studied in order to understand its variability especially during the onset of monsoon. During the building up of south-west monsoon, the specific humidity increases to ˜ 10g/kg in the altitude range of 4-6 km and consistently maintained it throughout the active spells and reduces to below 2g/kg during break spells of monsoon. The instrument details and the results will be presented.

Triggering processes of microseismic events associated with water injection in Okuaizu Geothermal Field, Japan

NASA Astrophysics Data System (ADS)

Okamoto, Kyosuke; Yi, Li; Asanuma, Hiroshi; Okabe, Takashi; Abe, Yasuyuki; Tsuzuki, Masatoshi

2018-02-01

A continuous water injection test was conducted to halt the reduction in steam production in the Okuaizu Geothermal Field, Japan. Understanding the factors triggering microseismicity associated with water injection is essential to ensuring effective steam production. We identified possible triggering processes by applying methods based on microseismic monitoring, including a new method to determine the presence of water in local fractures using scattered P-waves. We found that the evolving microseismicity near the injection point could be explained by a diffusion process and/or water migration. We also found that local microseismicity on a remote fault was likely activated by stress fluctuations resulting from changes in the injection rate. A mediator of this fluctuation might be water remaining in the fracture zone. After the injection was terminated, microseismicity possibly associated with the phase transition of the liquid was found. We conclude that a variety of triggering processes associated with water injection may exist.[Figure not available: see fulltext.

Analysis of Tests of Subsurface Injection, Storage, and Recovery of Freshwater in Lancaster, Antelope Valley, California

USGS Publications Warehouse

Phillips, Steven P.; Carlson, Carl S.; Metzger, Loren F.; Howle, James F.; Galloway, Devin L.; Sneed, Michelle; Ikehara, Marti E.; Hudnut, Kenneth W.; King, Nancy E.

2003-01-01

Ground-water levels in Lancaster, California, declined more than 200 feet during the 20th century, resulting in reduced ground-water supplies and more than 6 feet of land subsidence. Facing continuing population growth, water managers are seeking solutions to these problems. Injection of imported, treated fresh water into the aquifer system when it is most available and least expensive, for later use during high-demand periods, is being evaluated as part of a management solution. The U.S. Geological Survey, in cooperation with the Los Angeles County Department of Public Works and the Antelope Valley-East Kern Water Agency, monitored a pilot injection program, analyzed the hydraulic and subsidence-related effects of injection, and developed a simulation/optimization model to help evaluate the effectiveness of using existing and proposed wells in an injection program for halting the decline of ground-water levels and avoiding future land subsidence while meeting increasing ground-water demand. A variety of methods were used to measure aquifer-system response to injection. Water levels were measured continuously in nested (multi-depth) piezometers and monitoring wells and periodically in other wells that were within several miles of the injection site. Microgravity surveys were done to estimate changes in the elevation of the water table in the absence of wells and to estimate specific yield. Aquifer-system deformation was measured directly and continuously using a dual borehole extensometer and indirectly using continuous Global Positioning System (GPS), first-order spirit leveling, and an array of tiltmeters. The injected water and extracted water were sampled periodically and analyzed for constituents, including chloride and trihalomethanes. Measured injection rates of about 750 gallons per minute (gal/min) per well at the injection site during a 5-month period showed that injection at or above the average extraction rates at that site (about 800 gal/min) was hydraulically feasible. Analyses of these data took many forms. Coupled measurements of gravity and water-level change were used to estimate the specific yield near the injection wells, which, in turn, was used to estimate areal water-table changes from distributed measurements of gravity change. Values of the skeletal components of aquifer-system storage, which are key subsidence-related characteristics of the system, were derived from continuous measurements of water levels and aquifer-system deformation. A numerical model of ground-water flow was developed for the area surrounding Lancaster and used to estimate horizontal and vertical hydraulic conductivities. A chemical mass balance was done to estimate the recovery of injected water. The ground-water-flow model was used to project changes in ground-water levels for 10 years into the future, assuming no injection, no change in pumping distribution, and forecasted increases in ground-water demand. Simulated ground-water levels decreased throughout the Lancaster area, suggesting that land subsidence would continue as would the depletion of ground-water supplies and an associated loss of well production capacity. A simulation/optimization model was developed to help identify optimal injection and extraction rates for 16 existing and 13 proposed wells to avoid future land subsidence and to minimize loss of well production capacity while meeting increasing ground-water demands. Results of model simulations suggest that these objectives can be met with phased installation of the proposed wells during the 10-year period. Water quality was not considered in the optimization, but chemical-mass-balance results indicate that a sustained injection program likely would have residual effects on the chemistry of ground water.

Driving force behind adsorption-induced protein unfolding: a time-resolved X-ray reflectivity study on lysozyme adsorbed at an air/water interface.

PubMed

Yano, Yohko F; Uruga, Tomoya; Tanida, Hajime; Toyokawa, Hidenori; Terada, Yasuko; Takagaki, Masafumi; Yamada, Hironari

2009-01-06

Time-resolved X-ray reflectivity measurements for lysozyme (LSZ) adsorbed at an air/water interface were performed to study the mechanism of adsorption-induced protein unfolding. The time dependence of the density profile at the air/water interface revealed that the molecular conformation changed significantly during adsorption. Taking into account previous work using Fourier transform infrared (FTIR) spectroscopy, we propose that the LSZ molecules initially adsorbed on the air/water interface have a flat unfolded structure, forming antiparallel beta-sheets as a result of hydrophobic interactions with the gas phase. In contrast, as adsorption continues, a second layer forms in which the molecules have a very loose structure having random coils as a result of hydrophilic interactions with the hydrophilic groups that protrude from the first layer.

Toward the Characterization of Mixed-Phase Clouds Using Remote Sensing

NASA Astrophysics Data System (ADS)

Andronache, C.

2015-12-01

Mixed-phase clouds consist of a mixture of ice particles and liquid droplets at temperatures below 0 deg C. They are present in all seasons in many regions of the world, account for about 30% of the global cloud coverage, and are linked to cloud electrification and aircraft icing. The mix of ice particles, liquid droplets, and water vapor is unstable, and such clouds are thought to have a short lifetime. A characteristic parameter is the phase composition of mixed-phase clouds. It affects the cloud life cycle and the rate of precipitation. This parameter is important for cloud parameters retrievals by radar, lidar, and satellite and is relevant for climate modeling. The phase transformation includes the remarkable Wegener-Bergeron-Findeisen (WBF) process. The direction and the rate of the phase transformations depend on the local thermodynamic and microphysical properties. Cloud condensation nuclei (CCN) and ice nuclei (IN) particles determine to a large extent cloud microstructure and the dynamic response of clouds to aerosols. The complexity of dynamics and microphysics involved in mixed-phase clouds requires a set of observational and modeling tools that continue to be refined. Among these techniques, the remote sensing methods provide an increasing number of parameters, covering large regions of the world. Thus, a series of studies were dedicated to stratiform mixed-phase clouds revealing longer lifetime than previously thought. Satellite data and aircraft in situ measurements in deep convective clouds suggest that highly supercooled water often occurs in vigorous continental convective storms. In this study, we use cases of convective clouds to discuss the feasibility of mixed-phase clouds characterization and potential advantages of remote sensing.

Diurnal variability of gas phase and surface water ethanol in southeastern North Carolina, USA

NASA Astrophysics Data System (ADS)

Kieber, R. J.; Powell, J. P.; Foley, L.; Mead, R. N.; Willey, J. D.; Avery, G. B.

2017-11-01

Diurnal variations in gas phase and surface water concentrations of ethanol and acetaldehyde were investigated at five locations in southeastern North Carolina, USA. There were distinct diurnal oscillations observed in gas phase concentrations with maxima occurring in late afternoon suggesting that photochemical production is an important process in the cycling of these analytes in the troposphere. The rapid decrease in concentrations after the mid day maximum suggests that there is also an atmospheric photochemical sink for both analytes most likely involving photo produced hydroxyl radicals with a half-life on the order of hours rather than days at ground level. Ethanol concentrations in the surface microlayer taken at the same time as gas phase samples had a very similar diurnal profile suggesting photochemical processes, in addition to atmospheric deposition, play a role in the aqueous phase cycling of both analytes. The concentration of ethanol and acetaldehyde increased significantly in flasks containing freshwater collected from the Cape Fear River exposed to simulated sunlight for 6 h underscoring the importance of in situ photochemical production. Results of this study are significant because they represent the first simultaneous analyses of the temporal variability of ethanol and acetaldehyde concentrations in the gas and aqueous phases. These measurements are essential in order to better define the processes involved in the global biogeochemical cycling of ethanol both now and in the future as our use of the biofuel continues to grow.

Extraordinary phase separation and segregation in vent fluids from the southern East Pacific Rise

USGS Publications Warehouse

Von Damm, Karen L.; Lilley, M.D.; Shanks, Wayne C.; Brockington, M.; Bray, A.M.; O'Grady, K. M.; Olson, E.; Graham, A.; Proskurowski, G.

2003-01-01

The discovery of Brandon vent on the southern East Pacific Rise is providing new insights into the controls on midocean ridge hydrothermal vent fluid chemistry. The physical conditions at the time ofsampling (287 bar and 405??C) place the Brandon fluids very close to the critical point of seawater (298 bar and 407??C). This permits in situ study of the effects of near criticalphenomena, which are interpreted to be the primary cause of enhanced transition metal transport in these fluids. Of the five orifices on Brandon sampled, three were venting fluids with less than seawater chlorinity, and two were venting fluids with greater than seawater chlorinity. The liquid phase orifices contain 1.6-1.9 times the chloride content of the vapors. Most other elements, excluding the gases, have this same ratio demonstrating the conservative nature of phase separation and the lack of subsequent water-rock interaction. The vapor and liquid phases vent at the same time from orifices within meters of each other on the Brandon structure. Variations in fluid compositions occur on a time scale of minutes. Our interpretation is that phase separation and segregation must be occurring 'real time' within the sulfide structure itself. Fluids from Brandon therefore provide an unique opportunity to understand in situ phase separation without the overprinting of continued water-rock interaction with the oceanic crust, as well as critical phenomena. ?? 2002 Elsevier Science B.V. All rights reserved.

Mold Flux Crystallization and Mold Thermal Behavior

NASA Astrophysics Data System (ADS)

Peterson, Elizabeth Irene

Mold flux plays a small but critical role in the continuous casting of steel. The carbon-coated powder is added at the top of the water-cooled copper mold, over time it melts and infiltrates the gap between the copper mold and the solidifying steel strand. Mold powders serve five primary functions: (1) chemical insulation, (2) thermal insulation, (3) lubrication between the steel strand and mold, (4) absorption of inclusions, and (5) promotion of even heat flux. All five functions are critical to slab casting, but surface defect prevention is primarily controlled through even heat flux. Glassy fluxes have high heat transfer and result in a thicker steel shell. Steels with large volumetric shrinkage on cooling must have a crystalline flux to reduce the radiative heat transfer and avoid the formation of cracks in the shell. Crystallinity plays a critical role in steel shell formation, therefore it is important to study the thermal conditions that promote each phase and its morphology. Laboratory tests were performed to generate continuous cooling transformation (CCT) and time-temperature-transformation (TTT) diagrams. Continuous cooling transformation tests were performed in an instrumented eight cell step chill mold. Results showed that cuspidine was the only phase formed in conventional fluxes and all observed structures were dendritic. An isothermal tin bath quench method was also developed to isothermally age glassy samples. Isothermal tests yielded different microstructures and different phases than those observed by continuous cooling. Comparison of aged tests with industrial flux films indicates similar faceted structures along the mold wall, suggesting that mold flux first solidifies as a glass along the mold wall, but the elevated temperature devitrifies the glassy structure forming crystals that cannot form by continuous cooling.

Continual in situ monitoring of pore water stable isotopes in the subsurface

NASA Astrophysics Data System (ADS)

Volkmann, T. H. M.; Weiler, M.

2014-05-01

Stable isotope signatures provide an integral fingerprint of origin, flow paths, transport processes, and residence times of water in the environment. However, the full potential of stable isotopes to quantitatively characterize subsurface water dynamics is yet unfolded due to the difficulty in obtaining extensive, detailed, and repeated measurements of pore water in the unsaturated and saturated zone. This paper presents a functional and cost-efficient system for non-destructive continual in situ monitoring of pore water stable isotope signatures with high resolution. Automatic controllable valve arrays are used to continuously extract diluted water vapor in soil air via a branching network of small microporous probes into a commercial laser-based isotope analyzer. Normalized liquid-phase isotope signatures are then obtained based on a specific on-site calibration approach along with basic corrections for instrument bias and temperature dependent isotopic fractionation. The system was applied to sample depth profiles on three experimental plots with varied vegetation cover in southwest Germany. Two methods (i.e., based on advective versus diffusive vapor extraction) and two modes of sampling (i.e., using multiple permanently installed probes versus a single repeatedly inserted probe) were tested and compared. The results show that the isotope distribution along natural profiles could be resolved with sufficiently high accuracy and precision at sampling intervals of less than four minutes. The presented in situ approaches may thereby be used interchangeably with each other and with concurrent laboratory-based direct equilibration measurements of destructively collected samples. It is thus found that the introduced sampling techniques provide powerful tools towards a detailed quantitative understanding of dynamic and heterogeneous shallow subsurface and vadose zone processes.

The Pilot Phase of the Global Soil Wetness Project Phase 3

NASA Astrophysics Data System (ADS)

Kim, H.; Oki, T.

2015-12-01

After the second phase of the Global Soil Wetness Project (GSWP2) as an early global continuous gridded multi-model analysis, a comprehensive set of land surface fluxes and state variables became available. It has been broadly utilized in the hydrology community, and its success has evolved to take advantages of recent scientific progress and to extend the relatively short time span (1986-1995) of the previous project. In the third phase proposed here (GSWP3), an extensive set of quantities for hydro-energy-eco systems will be produced to investigate their long-term (1901-2010) changes. The energy-water-carbon cycles and their interactions are also examined subcomponent-wise with appropriate model verifications in ensemble land simulations. In this study, the preliminary results and problems found from the first round analysis of the GSWP3 pilot study are shown. Also, it is discussed how the global offline simulation activity contributes to wider communities and a bigger scope such as Climate Model Intercomparison Project Phase 6 (CMIP6).

Leaching of cadmium and tellurium from cadmium telluride (CdTe) thin-film solar panels under simulated landfill conditions

PubMed Central

Ramos-Ruiz, Adriana; Wilkening, Jean V.; Field, James A.; Sierra-Alvarez, Reyes

2017-01-01

A crushed non-encapsulated CdTe thin-film solar cell was subjected to two standardized batch leaching tests (i.e., Toxicity Characteristic Leaching Procedure (TCLP) and California Waste Extraction Test (WET)) and to a continuous-flow column test to assess cadmium (Cd) and tellurium (Te) dissolution under conditions simulating the acidic- and the methanogenic phases of municipal solid waste landfills. Low levels of Cd and Te were solubilized in both batch leaching tests (<8.2% and <3.6% of added Cd and Te, respectively). On the other hand, over the course of 30 days, 73% of the Cd and 21% of the Te were released to the synthetic leachate of a continuous-flow column simulating the acidic landfill phase. The dissolved Cd concentration was 3.24-fold higher than the TCLP limit (1 mg L-1), and 650-fold higher than the maximum contaminant level established by the US-EPA for this metal in drinking water (0.005 mg L-1). In contrast, the release of Cd and Te to the effluent of the continuous-flow column simulating the methanogenic phase of a landfill was negligible. The remarkable difference in the leaching behavior of CdTe in the columns is related to different aqueous pH and redox conditions promoted by the microbial communities in the columns, and is in agreement with thermodynamic predictions. PMID:28472709

Solid colloidal particles inducing coalescence in bitumen-in-water emulsions.

PubMed

Legrand, J; Chamerois, M; Placin, F; Poirier, J E; Bibette, J; Leal-Calderon, F

2005-01-04

Silica particles are dispersed in the continuous phase of bitumen-in-water emulsions. The mixture remains dispersed in quiescent storage conditions. However, rapid destabilization occurs once a shear is applied. Observations under the microscope reveal that the bitumen droplets form a colloidal gel and coalesce upon application of a shear. We follow the kinetic evolution of the emulsions viscosity, eta, at constant shear rate: eta remains initially constant and exhibits a dramatic increase after a finite time, tau. We study the influence of various parameters on the evolution of tau: bitumen droplet size and volume fraction, silica diameter and concentration, shear rate, etc.

Liquid jet pumped by rising gas bubbles

NASA Technical Reports Server (NTRS)

Hussain, N. A.; Siegel, R.

1975-01-01

A two-phase mathematical model is proposed for calculating the induced turbulent vertical liquid flow. Bubbles provide a large buoyancy force and the associated drag on the liquid moves the liquid upward. The liquid pumped upward consists of the bubble wakes and the liquid brought into the jet region by turbulent entrainment. The expansion of the gas bubbles as they rise through the liquid is taken into account. The continuity and momentum equations are solved numerically for an axisymmetric air jet submerged in water. Water pumping rates are obtained as a function of air flow rate and depth of submergence. Comparisons are made with limited experimental information in the literature.

Long-term trends of surface-water mercury and methylmercury concentrations downstream of historic mining within the Carson River watershed

USGS Publications Warehouse

Morway, Eric D.; Thodal, Carl E.; Marvin-DiPasquale, Mark C.

2017-01-01

The Carson River is a vital water resource for local municipalities and migratory birds travelling the Pacific Flyway. Historic mining practices that used mercury (Hg) to extract gold from Comstock Lode ore has left much of the river system heavily contaminated with Hg, a practice that continues in many parts of the world today. Between 1998 and 2013, the United States Geological Survey (USGS) collected and analyzed Carson River water for Hg and methylmercury (MeHg) concentrations resulting in a sixteen year record of unfiltered total mercury (uf.THg), filtered (dissolved) Hg (f.THg), total methylmercury (uf.MeHg), filtered MeHg (f.MeHg), and particulate-bound THg (p.THg) and MeHg (p.MeHg) concentrations. This represents one of the longest continuous records of Hg speciation data for any riverine system, thereby providing a unique opportunity to evaluate long-term trends in concentrations and annual loads. During the period of analysis, uf.THg concentration and load trended downward at rates of −0.85% and −1.8% per year, respectively. Conversely, the f.THg concentration increased at a rate of 1.7% per year between 1998 and 2005, and 4.9% per year between 2005 and 2013. Trends in flow-normalized partition coefficients for both Hg and MeHg suggest a statistically significant shift from the particulate to the filtered phase. The upwardly accelerating f.THg concentration and observed shift from the solid phase to the aqueous phase among the pools of Hg and MeHg within the river water column signals an increased risk of deteriorating ecological conditions in the lower basin with respect to Hg contamination. More broadly, the 16-year trend analysis, completed 140 years after the commencement of major Hg releases to the Carson River, provides a poignant example of the ongoing legacy left behind by gold and silver mining techniques that relied on Hg amalgamation, and a cautionary tale for regions still pursuing the practice in other countries.

Evaluation of geophysical logs, Phase II, at Willow Grove Naval Air Station Joint Reserve Base, Montgomery County, Pennsylvania

USGS Publications Warehouse

Conger, Randall W.

1999-01-01

Between March and April 1998, the U.S. Navy contracted Tetra Tech NUS Inc., to drill two monitor wells in the Stockton Formation at the Willow Grove Naval Air Station Joint Reserve Base, Horsham Township, Montgomery County, Pa. The wells MG-1634 and MG-1635 were installed to monitor water levels and sample contaminants in the shallow, intermediate, and deep water-producing zones of the fractured bedrock. Chemical analyses of the samples will help determine the horizontal and vertical distribution of any contaminated ground water migrating from known contaminant sources. Wells were drilled near the Fire Training Area (Site 5). Depths of all boreholes range from 69 to 149 feet below land surface. The U.S. Geological Survey conducted borehole geophysical logging and video surveys to identify water-producing zones in newly drilled monitor wells MG-1634 and MG-1635 and in wells MG-1675 and MG-1676. The logging was conducted from March 5, 1998, to April 16, 1998. This work is a continuation of the Phase I work. Caliper logs and video surveys were used to locate fractures; inflections on fluid-temperature and fluid-resistivity logs were used to locate possible water-producing fractures. Heatpulse-flowmeter measurements were used to verify the locations of water-producing or water-receiving zones and to measure rates of flow between water-bearing fractures. Single-point-resistance and natural-gamma logs provided information on stratigraphy. After interpretation of geophysical logs, video surveys, and driller's notes, wells MG-1634 and MG-1635 were screened such that water-levels fluctuations could be monitored and discrete water samples collected from one or more water-producing zones in each borehole.

Modes of supraglacial lake drainage and dynamic ice sheet response

NASA Astrophysics Data System (ADS)

Das, S. B.; Behn, M. D.; Joughin, I. R.

2011-12-01

We investigate modes of supraglacial lake drainage using geophysical, ground, and remote sensing observations over the western margin of the Greenland ice sheet. Lakes exhibit a characteristic life cycle defined by a pre-drainage, drainage, and post-drainage phase. In the pre-drainage phase winter snow fills pre-existing cracks and stream channels, efficiently blocking past drainage conduits. As temperatures increase in the spring, surface melting commences, initially saturating the snow pack and subsequently forming a surface network of streams that fills the lake basins. Basins continue to fill until lake drainage commences, which for individual lakes occurs at different times depending on the previous winter snow accumulation and summer temperatures. Three styles of drainage behavior have been observed: (1) no drainage, (2) slow drainage over the side into an adjacent pre-existing crack, and (3) rapid drainage through a new crack formed beneath the lake basin. Moreover, from year-to-year individual lakes exhibit different drainage behaviors. Lakes that drain slowly often utilize the same outflow channel for multiple years, creating dramatic canyons in the ice. Ultimately, these surface channels are advected out of the lake basin and a new channel forms. In the post-drainage phase, melt water continues to access the bed typically through a small conduit (e.g. moulin) formed near a local topographic minimum along the main drainage crack, draining the lake catchment throughout the remainder of the melt season. This melt water input to the bed leads to continued basal lubrication and enhanced ice flow compared to background velocities. Lakes that do not completely drain freeze over to form a surface ice layer that persists into the following year. Our results show that supraglacial lakes show a spectrum of drainage behaviors and that these styles of drainage lead to varying rates and timing of surface meltwater delivery to the bed resulting in different dynamic ice responses.

Thermodynamical effects accompanied freezing of two water layers separated by sea ice sheet

NASA Astrophysics Data System (ADS)

Bogorodsky, Petr; Marchenko, Aleksey

2014-05-01

The process of melt pond freezing is very important for generation of sea ice cover thermodynamic and mass balance during winterperiod. However, due to significant difficulties of field measurements the available data of model estimations still have no instrumental confirmation. In May 2009 the authors carried out laboratory experiment on freezing of limited water volume in the University Centre in Svalbard ice tank. In the course of experiment fresh water layer of 27.5 cm thickness at freezing point poured on the 24 cm sea ice layer was cooled during 50 hours at the temperature -10º C and then once again during 60 hours at -20º C. For revealing process typical characteristics the data of continuous measurements of temperature and salinity in different phases were compared with data of numerical computations obtained with thermodynamic model which was formulated in the frames of 1-D equation system (infinite extension of water freezing layer) and adapted to laboratory conditions. The known surprise of the experiment became proximity of calculated and measured estimates of process dynamics that confirmed the adequacy of the problem mathematical statement (excluding probably process finale stage). This effect can be explained by formation of cracks on the upper layer of ice at sharp decreases of air temperature, which temporary compensated hydrostatic pressure growth during freezing of closed water volume. Another compensated mechanism can be migration of brine through the lower layer of ice under influence of vertical pressure gradient and also rejection of gas dissolved in water which increased its compressibility. During 110 hours cooling thickness of water layer between ice layers reduced approximately to 2 cm. According to computations this layer is not chilled completely but keeps as thin brine interlayer within ice body whose thickness (about units of mm) is determined by temperature fluctuations of cooled surface. Nevertheless, despite good coincidence of experimental and model estimates the question of existence of liquid phase under actual conditions is still open and can be clarified in a continuous laboratory experiment. This work was supported by Russian Foundation for Basic Research (Project # 14-05-00677).

Liquid Water Transport in the Reactant Channels of Proton Exchange Membrane Fuel Cells

NASA Astrophysics Data System (ADS)

Banerjee, Rupak

Water management has been identified as a critical issue in the development of PEM fuel cells for automotive applications. Water is present inside the PEM fuel cell in three phases, i.e. liquid phase, vapor phase and mist phase. Liquid water in the reactant channels causes flooding of the cell and blocks the transport of reactants to the reaction sites at the catalyst layer. Understanding the behavior of liquid water in the reactant channels would allow us to devise improved strategies for removing liquid water from the reactant channels. In situ fuel cell tests have been performed to identify and diagnose operating conditions which result in the flooding of the fuel cell. A relationship has been identified between the liquid water present in the reactant channels and the cell performance. A novel diagnostic technique has been established which utilizes the pressure drop multiplier in the reactant channels to predict the flooding of the cell or the drying-out of the membrane. An ex-situ study has been undertaken to quantify the liquid water present in the reactant channels. A new parameter, the Area Coverage Ratio (ACR), has been defined to identify the interfacial area of the reactant channel which is blocked for reactant transport by the presence of liquid water. A parametric study has been conducted to study the effect of changing temperature and the inlet relative humidity on the ACR. The ACR decreases with increase in current density as the gas flow rates increase, removing water more efficiently. With increase in temperature, the ACR decreases rapidly, such that by 60°C, there is no significant ACR to be reported. Inlet relative humidity of the gases does change the saturation of the gases in the channel, but did not show any significant effect on the ACR. Automotive powertrains, which is the target for this work, are continuously faced with transient changes. Water management under transient operating conditions is significantly more challenging and has not been investigated in detail. This study begins to investigate the effects of changing operating conditions on liquid water transport through the reactant channels. It has been identified that rapidly increasing temperature leads to the dry-out of the membrane and rapidly cooling the cell below 55°C results in the start of cell flooding. In changing the operating load of the PEMFC, overshoot in the pressure drop in the reactant channel has been identified for the first time as part of this investigation. A parametric study has been conducted to identify the factors which influence this overshoot behavior.

Eddy correlation measurements of size-dependent cloud droplet turbulent fluxes to complex terrain

NASA Astrophysics Data System (ADS)

Vong, Richard J.; Kowalski, Andrew S.

1995-07-01

An eddy correlation technique was used to measure the turbulent flux of cloud droplets to complex, forested terrain near the coast of Washington State during the spring of 1993. Excellent agreement was achieved for cloud liquid water content measured by two instruments. Substantial downward liquid water fluxes of 1mm per 24 h were measured at night during "steady and continuous" cloud events, about twice the magnitude of those measured by Beswick etal. in Scotland. Cloud water chemical fluxes were estimated to represent up to 50% of the chemical deposition associated with precipitation at the site. An observed size-dependence in the turbulent liquid water fluxes suggested that both droplet impaction, which leads to downward fluxes, and phase change processes, which can lead to upward fluxes, consistently are important contributors to the eddy correlation results. The diameter below which phase change processes were important to observed fluxes was shown to depend upon σL, the relative standard deviation of the liquid water content (LWC) within a 30-min averaging period. The crossover from upward to downward LW flux occurs at 8µm for steady and continuous cloud events but at 13µm for events with a larger degree of LWC variability. This comparison of the two types of cloud events suggested that evaporation was the most likely cause of upward droplet fluxes for the smaller droplets (dia<13µm) during cloud with variable LWC (σL>0.3).

Water, Water Everywhere: Phase Diagrams of Ordinary Water Substance

ERIC Educational Resources Information Center

Glasser, L.

2004-01-01

The full phase diagram of water in the form of a graphical representation of the three-dimensional (3D) PVT diagram using authentic data is presented. An interesting controversy regarding the phase behavior of water was the much-touted proposal of a solid phase of water, polywater, supposedly stable under atmospheric conditions.

Mars Geological Province Designations for the Interpretation of GRS Data

NASA Technical Reports Server (NTRS)

Dohm, J. M.; Kerry, K.; Baker, V. R.; Boynton, W.; Maruyama, Shige; Anderson, R. C.

2005-01-01

Introduction: An overarching geologic theory, GEOMARS, coherently explains many otherwise anomalous aspects of the geological history of Mars. Premises for a theory of martian geologic evolution include: (1) Mars is a water-rich terrestrial planet, (2) terrestrial planets should evolve through progressive stages of dynamical history (accretion, differentiation, tectonism) and mantle convection (magma ocean, plate tectonism, stagnant lid), and (3) the early history of Earth affords an analogue to the evolution of Mars. The theory describes the following major stages of evolution for Mars (from oldest to youngest): Stage 1 - shortly after accretion, Mars differentiates to a liquid metallic core, a mantle boundary (MBL) of high-pressure silicate mineral phases, upper mantle, magma ocean, thin komatiic crust, and convecting steam atmosphere; Stage 2- Mars cools to condense its steam atmosphere and transform its mode of mantle convection to plate tectonism; subduction of waterrich oceanic crust initiates arc volcanism and transfers water, carbonates and sulfates to the mantle; Stage 3 - the core dynamo initiates, and the associated magnetosphere leads to conditions conducive to the development of near-surface life and photosynthetic production of oxygen; Stage 4 - accretion of thickened, continental crust and subduction of hydrated oceanic crust to the mantle boundary layer and lower mantle of Mars occurs; Stage 5 - the core dynamo stops during Noachian heavy bombardment while plate tectonism continues; Stage 6 - initiation of the Tharsis superplume (approx. between 4.0 and 3.8Ga) occurs, and Stage 7 - the superlume phase (stagnant-lid regime) of martian planetary evolution with episodic phases of volcanism and water outflows continues into the present. The GEOMARS Theory is testable through a multidisciplinary approach, including utilizing GRS-based information. Based on a synthesis of published geologic, paleohydrologic, topographic, geophysical, spectral, and elemental information, we have defined geologic provinces that represent significant windows into the geological evolution of Mars, unfolding the GEOMARS Theory and forming the basis for interpreting GRS data.

A Study of Chemical Reactions and Interactions in Microemulsion and Surfactant Phases.

DTIC Science & Technology

1982-07-19

purpose of this study was to continue in depth investigations of the utility of microemulsion systems for studies of interactions at microcopic oil...which contain one or more amphiphilic compounds and are mechanically stable. However, the crux of the problem concerning the definition of a...microemulsion is a "persistent translucent combination of oil and water that may contain electrolytes and one or more amphiphilic compounds ". The definition

Installation Restoration Program. Phase 2. Confirmation, Edwards AFB, California

DTIC Science & Technology

1982-09-01

aquifer boundaries has created unique hydrological conditions, with fluctuating water levels and continuously changing regimes of confinement...wells, resulting in changes in the regional gradien,ý from north to south. Figure 2.3 shows the groundwater table contours as of 1979 (U.S.G.S., 1980...of 11 inches. The maximum mean monthly rainfall occurs in February with about 0.5 inch in one day (Envirodyne Engineers, Inc., 1981). In arid climates

Skeletal growth phases of the cold-water coral Lophelia pertusa shown by scanning electron microscope and electron backscatter diffraction

NASA Astrophysics Data System (ADS)

Mouchi, Vincent; Vonlanthen, Pierre; Verrecchia, Eric P.; Crowley, Quentin G.

2016-04-01

Lophelia pertusa is a cold-water coral, which may form reefs by the association of multiple coralites within which a polyp lives. Each individual polyp builds an aragonite skeleton by an initial phase of early mineralization (traditionally referred to as centres of calcification) from which aragonite fibres grow in thickening deposits. The skeleton wall features successive optically opaque and translucent bands previously attributed to different regimes of growth as either uniform in crystal orientation (translucent bands) or with a chaotic organization (opaque bands). The processes involved in any organizational changes are still unknown. Microlayers in the coral wall, which represent separate periods of skeletal growth, have been recently identified and described. These growth patterns are readily visible under scanning electron microscope (SEM) after etching in dilute formic acid, but they do not necessarily form continuously visible structures. Here we present high quality SEM images and electron backscatter diffraction (EBSD) maps to study aragonite fibre orientation across the wall of L. pertusa. Both microlayers and opaque and translucent bands are compared to the crystallographic orientation of the aragonite fibres. EBSD maps and SEM images indicate that aragonite fibres do not exhibit a chaotic orientation, even in opaque bands. The absence of continuity of microlayers is partially explained by an association of multiple crystallographic preferred orientations of aragonite fibres. In the case of L. pertusa, careful textural characterisation is necessary prior to elemental or isotope analysis in order to select a skeletal transect representing a linear and continuous time period.

Lower critical solution temperature (LCST) phase separation of glycol ethers for forward osmotic control.

PubMed

Nakayama, Daichi; Mok, Yeongbong; Noh, Minwoo; Park, Jeongseon; Kang, Sunyoung; Lee, Yan

2014-03-21

Lower critical solution temperature (LCST) phase transition of glycol ether (GE)-water mixtures induces an abrupt change in osmotic pressure driven by a mild temperature change. The temperature-controlled osmotic change was applied for the forward osmosis (FO) desalination. Among three GEs evaluated, di(ethylene glycol) n-hexyl ether (DEH) was selected as a potential FO draw solute. A DEH-water mixture with a high osmotic pressure could draw fresh water from a high-salt feed solution such as seawater through a semipermeable membrane at around 10 °C. The water-drawn DEH-water mixture was phase-separated into a water-rich phase and a DEH-rich phase at around 30 °C. The water-rich phase with a much reduced osmotic pressure released water into a low-salt solution, and the DEH-rich phase was recovered into the initial DEH-water mixture. The phase separation behaviour, the residual GE concentration in the water-rich phase, the osmotic pressure of the DEH-water mixture, and the osmotic flux between the DEH-water mixture and salt solutions were carefully analysed for FO desalination. The liquid-liquid phase separation of the GE-water mixture driven by the mild temperature change between 10 °C and 30 °C is very attractive for the development of an ideal draw solute for future practical FO desalination.

The Effect of Organic Compounds on the Hygroscopic Properties of Inorganic Aerosol

NASA Astrophysics Data System (ADS)

Krieger, U. K.; Zardini, A. A.; Marcolli, C.

2006-12-01

The hygroscopicity of the aerosols plays a major role for the direct and indirect effect on the climate. It is known that aerosols are often a mixture of inorganic and organic matter. A significant fraction of the organic matter is water soluble (WSOC) and affects light scattering, water uptake and phase transitions of multicomponent aerosols. Additionally, organic matter can act as a surfactant around an inorganic particle, affecting the evaporation-condensation time scale. This research project benefits from the combined measurements performed by two different instrumentations: the electrodynamic trap at IACETH, Zürich, Switzerland, and a Tandem Differential Mobility Analizer (TDMA) at the Paul Scherrer Institute, Switzerland. The Electrodynamic Trap consists of a chamber in which a levitated particle can experience all the atmospherically relevant conditions of temperature, pressure, and humidity. All these parameters can be continuously varied so that the hygroscopic curve of the aerosol particle can be measured. Additional tools help to better characterize the aerosol particle: 90 degrees angular scattering of lasers (for radius measurements) and intensity fluctuation of the scattered light with time (for phase changes detection). In this poster the results obtained through the electrodynamic balance technique will be shown and compared with the TDMA. In particular, bicomponent ammonium sulphate with adipic acid bicomponent particles are studied, with different mixing ratios. Particular emphasis is put on assessing the water uptake and the phase changes of the particles.

Organochlorine pesticide contamination of ground water in the city of Hyderabad.

PubMed

Shukla, Gangesh; Kumar, Anoop; Bhanti, Mayank; Joseph, P E; Taneja, Ajay

2006-02-01

Organochlorine pesticides are ubiquitous and persistent organic pollutants used widely throughout the world. Due to the extensive use in agriculture, organic environmental contaminants such as HCH, DDT along with other organochlorine pesticides are distributed globally by transport through air and water. The main aim of present study is to determine contamination levels of organochlorine pesticides in the ground water of Hyderabad City. Water samples were collected from 28 domestic well supplies of the city. For this study, random sampling technique was applied, all the samples were collected in high purity glass bottles and refrigerated at 4 degrees C until analysis. Solid Phase Extraction (SPE) is used for the extraction of organochlorine pesticide residues in water sample. The collected water samples were pre-filtered through a 0.45 microg glass fiber filter (Wattman GF/F) to remove particulate matter and were acidified with hydrochloric acid (6N) to pH 2.5. Methanol modifier (BDH, for pesticide residue analysis, 10 mL) was added to water sample for better extraction. SPE using pre-packed reversed phase octadecyl (C-18 bonded silica) contained in cartridges was used for sample preparation. Prior to the extraction, the C-18 bonded phase, which contains 500 mg of bonded phase, was washed with 20 mL methanol. The sample was mixed well and allowed to percolate through the cartridges with flow rate of 10-15 mL/min under vacuum. After sample extraction, suction continued for 15 min to dry the packing material and pesticides trapped in the C-18 bonded phases were eluted by passing 10 mL hexane and fraction was evaporated in a gentle steam of Nitrogen. In all samples pesticide residues were analyzed by GC (Chemito-8510) with Ni63 ECD detector. Helium was used as carrier gas and nitrogen was used as make up gas. The injection technique was split/split less. All the samples analyzed were found to be contaminated with four pesticides i.e. DDT, beta-Endosulfan, alpha-Endosulfan and Lindane. DDT was found to range between 0.15 and 0.19 microg L(-1), beta-Endosulfan ranges between 0.21 and 0.87 microg L(-1), alpha-Endosulfan ranges between 1.34 and 2.14 microg L(-1) and Lindane ranges between 0.68 and 1.38 microg L(-1) respectively. These concentrations of pesticides in the water samples were found to be above their respective Acceptable Daily Intake (ADI) values for Humans.

Community shift of biofilms developed in a full-scale drinking water distribution system switching from different water sources.

PubMed

Li, Weiying; Wang, Feng; Zhang, Junpeng; Qiao, Yu; Xu, Chen; Liu, Yao; Qian, Lin; Li, Wenming; Dong, Bingzhi

2016-02-15

The bacterial community of biofilms in drinking water distribution systems (DWDS) with various water sources has been rarely reported. In this research, biofilms were sampled at three points (A, B, and C) during the river water source phase (phase I), the interim period (phase II) and the reservoir water source phase (phase III), and the biofilm community was determined using the 454-pyrosequencing method. Results showed that microbial diversity declined in phase II but increased in phase III. The primary phylum was Proteobacteria during three phases, while the dominant class at points A and B was Betaproteobacteria (>49%) during all phases, but that changed to Holophagae in phase II (62.7%) and Actinobacteria in phase III (35.6%) for point C, which was closely related to its water quality. More remarkable community shift was found at the genus level. In addition, analysis results showed that water quality could significantly affect microbial diversity together, while the nutrient composition (e.g. C/N ration) of the water environment might determine the microbial community. Furthermore, Mycobacterium spp. and Pseudomonas spp. were detected in the biofilm, which should give rise to attention. This study revealed that water source switching produced substantial impact on the biofilm community. Copyright © 2015 Elsevier B.V. All rights reserved.

Different magnesium release profiles from W/O/W emulsions based on crystallized oils.

PubMed

Herzi, Sameh; Essafi, Wafa

2018-01-01

Water-in-oil-in-water (W/O/W) double emulsions based on crystallized oils were prepared and the release kinetics of magnesium ions from the internal to the external aqueous phase was investigated at T=4°C, for different crystallized lipophilic matrices. All the emulsions were formulated using the same surface-active species, namely polyglycerol polyricinoleate (oil-soluble) and sodium caseinate (water-soluble). The external aqueous phase was a lactose or glucose solution at approximately the same osmotic pressure as that of the inner droplets, in order to avoid osmotic water transfer phenomena. We investigated two types of crystallized lipophilic systems: one based on blends of cocoa butter and miglyol oil, exploring a solid fat content from 0 to 90% and the other system based on milk fat fractions for which the solid fat content varies between 54 and 86%. For double emulsions based on cocoa butter/miglyol oil, the rate of magnesium release was gradually lowered by increasing the % of fat crystals i.e. cocoa butter, in agreement with a diffusion/permeation mechanism. However for double emulsions based on milk fat fractions, the rate of magnesium release was independent of the % of fat crystals and remains the one at t=0. This difference in diffusion patterns, although the solid content is of the same order, suggests a different distribution of fat crystals within the double globules: a continuous fat network acting as a physical barrier for the diffusion of magnesium for double emulsions based on cocoa butter/miglyol oil and double globule/water interfacial distribution for milk fat fractions based double emulsions, through the formation of a crystalline shell allowing an effective protection of the double globules against diffusion of magnesium to the external aqueous phase. Copyright © 2017 Elsevier Inc. All rights reserved.

Geochemical and Hydrologic Controls of Copper-Rich Surface Waters in the Yerba Loca-Mapocho System

NASA Astrophysics Data System (ADS)

Pasten, P.; Montecinos, M.; Coquery, M.; Pizarro, G. E.; Abarca, M. I.; Arce, G. J.

2015-12-01

Andean watersheds in Northern and Central Chile are naturally enriched with metals, many of them associated to sulfide mineralizations related to copper mining districts. The natural and anthropogenic influx of toxic metals into drinking water sources pose a sustainability challenge for cities that need to provide safe water with the smallest footprint. This work presents our study of the transformations of copper in the Yerba Loca-Mapocho system. Our sampling campaign started from the headwaters at La Paloma Glacier and continues to the inlet of the San Enrique drinking water treatment plant, a system feeding municipalities in the Eastern area of Santiago, Chile. Depending on the season, total copper concentrations go as high as 22 mg/L for the upper sections, which become diluted to <5 mg/L downstream. pH ranged from 3 to 5.6 while suspended solids ranged from <10 to 100 mg/L. We used Geochemist Workbench to assess copper speciation and to evaluate the thermodynamic controls for the formation and dissolution of solid phases. A sediment trap was used to concentrate suspended particulate matter, which was analyzed with ICP-MS, TXRF (total reflection X ray fluorescence) and XRD (X-ray diffraction). Major elements detected in the precipitates were Al (200 g/kg), S (60 g/kg), and Cu (6 g/kg). Likely solid phases include hydrous amorphous phases of aluminum hydroxides and sulfates, and copper hydroxides/carbonates. Efforts are undergoing to find the optimal mixing ratios between the acidic stream and more alkaline streams to maximize attenuation of dissolved copper. The results of this research could be used for enhancing in-stream natural attenuation of copper and reducing treatment needs at the drinking water facility. Acknowledgements to Fondecyt 1130936 and Conicyt Fondap 15110020

Blood glucose regulation during living-donor liver transplant surgery.

PubMed

Gedik, Ender; İlksen Toprak, Hüseyin; Koca, Erdinç; Şahin, Taylan; Özgül, Ülkü; Ersoy, Mehmet Özcan

2015-04-01

The goal of this study was to compare the effects of 2 different regimens on blood glucose levels of living-donor liver transplant. The study participants were randomly allocated to the dextrose in water plus insulin infusion group (group 1, n = 60) or the dextrose in water infusion group (group 2, n = 60) using a sealed envelope technique. Blood glucose levels were measured 3 times during each phase. When the blood glucose level of a patient exceeded the target level, extra insulin was administered via a different intravenous route. The following patient and procedural characteristics were recorded: age, sex, height, weight, body mass index, end-stage liver disease, Model for End-Stage Liver Disease score, total anesthesia time, total surgical time, and number of patients who received an extra bolus of insulin. The following laboratory data were measured pre- and postoperatively: hemoglobin, hematocrit, platelet count, prothrombin time, international normalized ratio, potassium, creatinine, total bilirubin, and albumin. No hypoglycemia was noted. The recipients exhibited statistically significant differences in blood glucose levels during the dissection and neohepatic phases. Blood glucose levels at every time point were significantly different compared with the first dissection time point in group 1. Excluding the first and second anhepatic time points, blood glucose levels were significantly different as compared with the first dissection time point in group 2 (P < .05). We concluded that dextrose with water infusion alone may be more effective and result in safer blood glucose levels as compared with dextrose with water plus insulin infusion for living-donor liver transplant recipients. Exogenous continuous insulin administration may induce hyperglycemic attacks, especially during the neohepatic phase of living-donor liver transplant surgery. Further prospective studies that include homogeneous patient subgroups and diabetic recipients are needed to support the use of dextrose plus water infusion without insulin.

Modeling 3H-3He Gas-Liquid Phase Transport for Interpretation of Groundwater Age

NASA Astrophysics Data System (ADS)

Carle, S. F.; Esser, B.; Moran, J. E.

2009-12-01

California’s Groundwater Ambient Monitoring and Assessment (GAMA) Program has measured many hundreds of tritium (3H) and helium-3 (3He) concentrations in well water samples to derive estimates of groundwater age at production and monitoring wells in California basins. However, a 3H-3He age differs from an ideal groundwater age tracer in several respects: (1) the radioactive decay of 3H results in the accumulation of 3He being first-order with respect to 3H activity (versus a zero-order age-mass accumulation process for an ideal tracer), (2) surface concentrations of 3H as measured in precipitation over the last several decades have not been uniform, and (3) the 3H-3He “clock” begins at the water table and not at the ground surface where 3H source measurements are made. To better understand how these non-idealities affect interpretation of 3H-3He apparent groundwater age, we are modeling coupled gas-liquid phase flow and 3H-3He transport including processes of radiogenic decay, phase equilibrium, and molecular diffusion for water, air, 3H, and 3He components continuously through the vadose zone and saturated zone. Assessment of coupled liquid-gas phase processes enables consideration of 3H-3He residence time and dispersion within the vadose zone, including partitioning of tritiogenic 3He to the gas phase and subsequent diffusion into the atmosphere. The coupled gas-liquid phase modeling framework provides direct means to compare apparent 3H-3He age to ideal mean or advective groundwater ages for the same groundwater flow conditions. Examples are given for common groundwater flow systems involving areal recharge, discharge to streams or long-screened wells, and aquifer system heterogeneity. The Groundwater Ambient Monitoring and Assessment program is sponsored by the California State Water Resources Control Board and carried out in cooperation with the U.S. Geological Survey. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Shallow subsurface imaging of northern Cascadia margin using downward continued short-streamer data

NASA Astrophysics Data System (ADS)

Yelisetti, S.; Ghosal, D.; Spence, G.

2017-12-01

Since Eocene, the Juan de Fuca plate has been subducting beneath the North American plate, scrapping off sediments from the down going plate, accreting to the margin forming frontal accretionary wedge, Crescent terrane and the Pacific Rim terrane, which are separated by landward dipping Crescent thrust and Tofino faults. In 1989, the Geological Survey of Canada has acquired several multichannel seismic lines along the northern Cascadia margin to study the subduction zone processes and the formation and distribution of methane hydrates in the accreted sediment section. Seismic reflections and refractions are recorded on a 3.6 km streamer up to 14 s using 4 ms sample rate with 183 m near-offset. In this study, we present the migrated image of line 89-06 which indicate the top of the down-going plate and several landward dipping frontal thrusts. Additionally, a bottom simulating reflector (BSR) is identified over a 20 km distance at a depth of 250 m beneath the seafloor within the accretionary wedge sediments where the water depth is around 1500-2000 m. Preliminary velocity analyses corresponding to the BSR reflection using semblance method indicate high-velocity sediment with P-wave velocities of 2.0 km/s. To better constrain the velocity distribution of such shallow subsurface features, we have analyzed the refracted arrivals from the seaward part of the Tofino basin sediment section. Specifically, we have downward continued the shot and receiver gathers to the seafloor bringing the far offset refracted phases to near offset as first arrivals. Since the refractions are not well captured over the trench deposits due to large water depth ( 2500 m) and limited streamer length, the downward continued results do not show refracted arrivals very clearly at the near offset. In contrast, moving landward along the frontal slope with gradual decrease in water depth to 1300 m and less, the effect of downward continuation seems to be more prominent bringing the refracted phases to near offset more clearly as first arrivals. More detailed first arrival tomographic velocity analysis is currently underway using these downward continued datasets. The tomographic velocity model will then be used as a starting model for future full waveform inversion to obtain the high-resolution velocity and attenuation models of the accreted sediments.

Experimental study on latent heat storage characteristics of W/O emulsion -Supercooling rate of dispersed water drops by direct contact heat exchange-

NASA Astrophysics Data System (ADS)

Morita, Shin-ichi; Hayamizu, Yasutaka; Horibe, Akihiko; Haruki, Naoto; Inaba, Hideo

2013-04-01

Recently, much attention has been paid to investigate the latent heat storage system. Using of ice heat storage system brings an equalization of electric power demand, because it will solved the electric -power-demand-concentration on day-time of summer by the air conditioning. The flowable latent heat storage material, Oil/Water type emulsion, microencapsulated latent heat material-water mixture or ice slurry, etc., is enable to transport the latent heat in a pipe. The flowable latent heat storage material can realize the pipe size reduction and system efficiency improvement. Supercooling phenomenon of the dispersed latent heat storage material in continuous phase brings the obstruction of latent heat storage. The latent heat storage rates of dispersed water drops in W/O (Water/Oil) emulsion are investigated experimentally in this study. The water drops in emulsion has the diameter within 3 ˜ 25μm, the averaged water drop diameter is 7.3μm and the standard deviation is 2.9μm. The direct contact heat exchange method is chosen as the phase change rate evaluation of water drops in W/O emulsion. The supercooled temperature and the cooling rate are set as parameters of this study. The evaluation is performed by comparison between the results of this study and the past research. The obtained experimental result is shown that the 35K or more degree from melting point brings 100% latent heat storage rate of W/O emulsion. It was clarified that the supercooling rate of dispersed water particles in emulsion shows the larger value than that of the bulk water.

Effects of experimental CO2 leakage on solubility and transport of seven trace metals in seawater and sediment.

PubMed

Ardelan, Murat V; Steinnes, Eiliv; Lierhagen, Syverin; Linde, Sven Ove

2009-12-01

The impact of CO(2) leakage on solubility and distribution of trace metals in seawater and sediment has been studied in lab scale chambers. Seven metals (Al, Cr, Ni, Pb, Cd, Cu, and Zn) were investigated in membrane-filtered seawater samples, and DGT samplers were deployed in water and sediment during the experiment. During the first phase (16 days), "dissolved" (<0.2 microm) concentrations of all elements increased substantially in the water. The increase in dissolved fractions of Al, Cr, Ni, Cu, Zn, Cd and Pb in the CO(2) seepage chamber was respectively 5.1, 3.8, 4.5, 3.2, 1.4, 2.3 and 1.3 times higher than the dissolved concentrations of these metals in the control. During the second phase of the experiment (10 days) with the same sediment but replenished seawater, the dissolved fractions of Al, Cr, Cd, and Zn were partly removed from the water column in the CO(2) chamber. DNi and DCu still increased but at reduced rates, while DPb increased faster than that was observed during the first phase. DGT-labile fractions (Me(DGT)) of all metals increased substantially during the first phase of CO(2) seepage. DGT-labile fractions of Al, Cr, Ni, Cu, Zn, Cd and Pb were respectively 7.9, 2.0, 3.6, 1.7, 2.1, 1.9 and 2.3 times higher in the CO(2) chamber than that of in the control chamber. Al(DGT), Cr(DGT), Ni(DGT), and Pb(DGT) continued to increase during the second phase of the experiment. There was no change in Cd(DGT) during the second phase, while Cu(DGT) and Zn(DGT) decreased by 30% and 25%, respectively in the CO(2) chamber. In the sediment pore water, DGT labile fractions of all the seven elements increased substantially in the CO(2) chamber. Our results show that CO(2) leakage affected the solubility, particle reactivity and transformation rates of the studied metals in sediment and at the sediment-water interface. The metal species released due to CO(2) acidification may have sufficiently long residence time in the seawater to affect bioavailability and toxicity of the metals to biota.

Increased Mediterranean Magma Production and Volcanism Triggered by the Messinian Salinity Crisis

NASA Astrophysics Data System (ADS)

Sternai, P.; Caricchi, L.; Garcia-Castellanos, D.; Jolivet, L.; Sheldrake, T.; Castelltort, S.

2017-12-01

For more than four decades, large controversies about the causes, effects and timing of the Mediterranean Messinian Salinity Crisis (MSC) have evolved in the light of a continuously growing body of evidences. The igneous response to such extreme event, however, has remained largely unexplored despite known relationships between surface load variations and the production, transfer and eruption of magma. Here, we compile published geochemical data and recognize a two-fold increase of volcanic eruptions from pan-Mediterranean magmatic provinces coinciding with the proposed "shallow-water phase" of the MSC between 5.70-5.33 Ma. Estimates of surface load variations due to the desiccation event corrected for water density change and deposition of salt deposits suggest a net mean lithospheric unloading of up to 15 MPa during the shallow-water phase of the MSC. Because the timescale of interest is too short for changes of the Mediterranean tectonics to significantly affect the bulk of the magma production, we propose that such net surface unloading enhanced the mantle decompression melting and dike formation, in turn causing the observed increase of volcanic events. If correct, the Mediterranean magmatic record provides an independent validation of the "shallow-water" model for the formation of salt deposits and testifies the high sensitivity of the melting of the Earth's interior to the surface forcing.

Phase I of the Kissimmee River restoration project, Florida, USA: impacts of construction on water quality.

PubMed

Colangelo, David J; Jones, Bradley L

2005-03-01

Phase I of the Kissimmee River restoration project included backfilling of 12 km of canal and restoring flow through 24 km of continuous river channel. We quantified the effects of construction activities on four water quality parameters (turbidity, total phosphorus flow-weighted concentration, total phosphorus load and dissolved oxygen concentration). Data were collected at stations upstream and downstream of the construction and at four stations within the construction zone to determine if canal backfilling and construction of 2.4 km of new river channel would negatively impact local and downstream water quality. Turbidity levels at the downstream station were elevated for approximately 2 weeks during the one and a half year construction period, but never exceeded the Florida Department of Environmental Protection construction permit criteria. Turbidity levels at stations within the construction zone were high at certain times. Flow-weighted concentration of total phosphorus at the downstream station was slightly higher than the upstream station during construction, but low discharge limited downstream transport of phosphorus. Total phosphorus loads at the upstream and downstream stations were similar and loading to Lake Okeechobee was not significantly affected by construction. Mean water column dissolved oxygen concentrations at all sampling stations were similar during construction.

Stabilization of ammonia-rich hydrate inside icy planets.

PubMed

Naden Robinson, Victor; Wang, Yanchao; Ma, Yanming; Hermann, Andreas

2017-08-22

The interior structure of the giant ice planets Uranus and Neptune, but also of newly discovered exoplanets, is loosely constrained, because limited observational data can be satisfied with various interior models. Although it is known that their mantles comprise large amounts of water, ammonia, and methane ices, it is unclear how these organize themselves within the planets-as homogeneous mixtures, with continuous concentration gradients, or as well-separated layers of specific composition. While individual ices have been studied in great detail under pressure, the properties of their mixtures are much less explored. We show here, using first-principles calculations, that the 2:1 ammonia hydrate, (H 2 O)(NH 3 ) 2 , is stabilized at icy planet mantle conditions due to a remarkable structural evolution. Above 65 GPa, we predict it will transform from a hydrogen-bonded molecular solid into a fully ionic phase O 2- ([Formula: see text]) 2 , where all water molecules are completely deprotonated, an unexpected bonding phenomenon not seen before. Ammonia hemihydrate is stable in a sequence of ionic phases up to 500 GPa, pressures found deep within Neptune-like planets, and thus at higher pressures than any other ammonia-water mixture. This suggests it precipitates out of any ammonia-water mixture at sufficiently high pressures and thus forms an important component of icy planets.

Representation of Arctic mixed-phase clouds and the Wegener-Bergeron-Findeisen process in climate models: Perspectives from a cloud-resolving study

NASA Astrophysics Data System (ADS)

Fan, Jiwen; Ghan, Steven; Ovchinnikov, Mikhail; Liu, Xiaohong; Rasch, Philip J.; Korolev, Alexei

2011-01-01

Two types of Arctic mixed-phase clouds observed during the ISDAC and M-PACE field campaigns are simulated using a 3-dimensional cloud-resolving model (CRM) with size-resolved cloud microphysics. The modeled cloud properties agree reasonably well with aircraft measurements and surface-based retrievals. Cloud properties such as the probability density function (PDF) of vertical velocity (w), cloud liquid and ice, regimes of cloud particle growth, including the Wegener-Bergeron-Findeisen (WBF) process, and the relationships among properties/processes in mixed-phase clouds are examined to gain insights for improving their representation in General Circulation Models (GCMs). The PDF of the simulated w is well represented by a Gaussian function, validating, at least for arctic clouds, the subgrid treatment used in GCMs. The PDFs of liquid and ice water contents can be approximated by Gamma functions, and a Gaussian function can describe the total water distribution, but a fixed variance assumption should be avoided in both cases. The CRM results support the assumption frequently used in GCMs that mixed phase clouds maintain water vapor near liquid saturation. Thus, ice continues to grow throughout the stratiform cloud but the WBF process occurs in about 50% of cloud volume where liquid and ice co-exist, predominantly in downdrafts. In updrafts, liquid and ice particles grow simultaneously. The relationship between the ice depositional growth rate and cloud ice strongly depends on the capacitance of ice particles. The simplified size-independent capacitance of ice particles used in GCMs could lead to large deviations in ice depositional growth.

Swimming for your life: locomotor effort and oxygen consumption during the green turtle (Chelonia mydas) hatchling frenzy.

PubMed

Booth, David T

2009-01-01

Swimming effort and oxygen consumption of newly emerged green turtle Chelonia mydas hatchlings was measured simultaneously and continuously for the first 18 h of swimming after hatchlings entered the water. Oxygen consumption was tightly correlated to swimming effort during the first 12 h of swimming indicating that swimming is powered predominantly by aerobic metabolism. The patterns of swimming effort and oxygen consumption could be divided into three distinct phases: (1) the rapid fatigue phase from 0 to 2 h when the mean swim thrust decreased from 45 to 30 mN and oxygen consumption decreased from 33 to 18 ml h(-1); (2) the slow fatigue phase from 2 to 12 h when the mean swim thrust decreased from 30 to 22 mN and oxygen consumption decreased from 18 to 10 ml h(-1); and (3) the sustained effort phase from 12 to 18 h when mean swim thrust averaged 22 mN and oxygen consumption averaged 10 ml h(-1). The decrease in mean swim thrust was caused by a combination of a decrease in front flipper stroke rate during a power stroking bout, a decrease in mean maximum thrust during a power stroking bout and a decrease in the proportion of time spent power stroking. Hence hatchlings maximise their swimming thrust as soon as they enter the water, a time when a fast swimming speed will maximise the chance of surviving the gauntlet of predators inhabiting the shallow fringing reef before reaching the relative safety of deeper water.

Adsorption of water from aqueous acetonitrile on silica-based stationary phases in aqueous normal-phase liquid chromatography.

PubMed

Soukup, Jan; Jandera, Pavel

2014-12-29

Excess adsorption of water from aqueous acetonitrile mobile phases was investigated on 16 stationary phases using the frontal analysis method and coulometric Karl-Fischer titration. The stationary phases include silica gel and silica-bonded phases with different polarities, octadecyl and cholesterol, phenyl, nitrile, pentafluorophenylpropyl, diol and zwitterionic sulfobetaine and phosphorylcholine ligands bonded on silica, hybrid organic-silica and hydrosilated matrices. Both fully porous and core-shell column types were included. Preferential uptake of water by the columns can be described by Langmuir isotherms. Even though a diffuse rather than a compact adsorbed discrete layer of water on the adsorbent surface can be formed because of the unlimited miscibility of water with acetonitrile, for convenience, the preferentially adsorbed water was expressed in terms of a hypothetical monomolecular water layer equivalent in the inner pores. The uptake of water strongly depends on the polarity and type of the column. Less than one monomolecular water layer equivalent was adsorbed on moderate polar silica hydride-based stationary phases, Ascentis Express F5 and Ascentis Express CN column at the saturation capacity, while on more polar stationary phases, several water layer equivalents were up-taken from the mobile phase. The strongest affinity to water was observed on the ZIC cHILIC stationary phases, where more than nine water layer equivalents were adsorbed onto its surface at its saturation capacity. Columns with bonded hydroxyl and diol ligands show stronger water adsorption in comparison to bare silica. Columns based on hydrosilated silica generally show significantly decreased water uptake in comparison to stationary phases bonded on ordinary silica. Significant correlations were found between the water uptake and the separation selectivity for compounds with strong polarity differences. Copyright © 2014 Elsevier B.V. All rights reserved.

Polarization gating of high harmonic generation in the water window

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

Li, Jie; Ren, Xiaoming; Yin, Yanchun

2016-06-06

We implement the polarization gating (PG) technique with a two-cycle, 1.7 μm driving field to generate an attosecond supercontinuum extending to the water window spectral region. The ellipticity dependence of the high harmonic yield over a photon energy range much broader than previous work is measured and compared with a semi-classical model. When PG is applied, the carrier-envelope phase (CEP) is swept to study its influence on the continuum generation. PG with one-cycle (5.7 fs) and two-cycle (11.3 fs) delay are tested, and both give continuous spectra spanning from 50 to 450 eV under certain CEP values, strongly indicating the generation ofmore » isolated attosecond pulses in the water window region.« less

High-performance liquid chromatographic analysis of methadone hydrochloride oral solution.

PubMed

Beasley, T H; Ziegler, H W

1977-12-01

A direct and rapid high-performance liquid chromatographic assay for methadone hydrochloride in a flavored oral solution dosage form is described. A syrup sample, one part diluted with three parts of water, is introduced onto a column packed with octadecylsilane bonded on 10 micrometer porous silica gel (reversed phase). A formic acid-ammonium formate-buffered mobile phase is linear programmed with acetonitrile. The absorbance is monitored continuously at 280 or 254 nm, using a flow-through, UV, double-beam photometer. An aqueous methadone hydrochloride solution is used for external standardization. The relative standard deviation was not more than 1.0%. Drug recovery from a syrup base was better than 99.8%.

Carrier phase altimetry using Zeppelin based GNSS-R observations and water gauge reference data

NASA Astrophysics Data System (ADS)

Semmling, Maximilian; Schön, Steffen; Beckheinrich, Jamila; Beyerle, Georg; Ge, Maorong; Wickert, Jens

2014-05-01

The increasing number of transmitters in global navigation satellite systems (GNSS), like GPS, Galileo, Glonass or Compass, provide observations with an increasing coverage for positioning but also for remote sensing. A space based GNSS remote sensing application is radio occultation, a limb sounding method. Globally distributed vertical profiles of temperature, water vapour and electron density are provided operationally for weather forecast and ionospheric monitoring. Another application is GNSS reflectometry (GNSS-R) that is currently developed especially for ocean remote sensing. The high reflection coefficient of water is crucial for GNSS-R. This study presents a method that uses GNSS phase observations for lake altimetry with the potential for ocean application. Phase observations are deduced from a GORS (GNSS Occultaction Reflectometry Scatterometry) receiver in Master-Slave-Configuration. The Master sampling dedicated for direct signal acquisition is connected to an up-looking antenna with right hand circular polarization (RHCP). Two Slave samplings dedicated for acquisition of the reflected signals are connected to down-looking antennas with right- and left-hand circular polarization (RHCP and LHCP). Based on in-phase and quad-phase (I, Q) sample components, an altimetric phase residual is retrieved. This residual can be related to the height of the reflecting surface. An altimetric challenge arises from the unknown ambiguity of phase residuals that introduces a height bias. The presented study uses ancillary data deduced from water gauges to mitigate the ambiguity bias. Reference tracks are formed by linear surface height interpolation between the water gauge stations. At crossover points of reflection tracks with reference tracks a phase ambiguity estimate is determined for bias mitigation. For this study airborne GNSS measurements were conducted aboard a Zeppelin NT (New Technology) airship with a geodetic receiver for navigation and a GORS receiver for reflectometry. The corresponding Zeppelin campaign was conducted in Sep 2012. It comprised three days with in total 13 flight hours over lake Constance (9.0°-9.8°E; 47.5°-47.8°N). Compared to a similar Zeppelin campaign in Oct 2010, Slave tracking problems could be solved providing reflection events with continuous tracks of up to 30min. The airship's trajectory is determined from navigation data with a precision better than 10cm in Precise Point Positioning mode supported by additional GNSS ground station data. Water gauge reference data around the lake is provided by stations at Friedrichshafen, Konstanz, Lindau and Romanshorn. Situated in vicinity of the Upper Rhine Plain the lake surface is affected by gravity anomalies in this region. As a consequence geoid undulations with up to 1m amplitude occur along the lake. Predictions of surface height undulation (including GCG-05 model) agree with phase altimetric retrievals. An example event shows a standard deviation of only 2cm (4cm) for RHCP (LHCP) data. The corresponding mean difference with 53cm (51cm) for RHCP (LHCP), respectively, is related to the residual ambiguity bias persisting after mitigation with reference data.

Challenges with Operating a Water Recovery System (WRS) in the Microgravity Environment of the International Space Station (ISS)

NASA Technical Reports Server (NTRS)

Carter, Donald Layne

2017-01-01

The ISS WRS produces potable water from crew urine, crew latent, and Sabatier product water. This system has been operational on ISS since November 2008, producing over 30,000 L of water during that time. The WRS includes a Urine Processor Assembly (UPA) to produce a distillate from the crew urine. This distillate is combined with the crew latent and Sabatier product water and further processed by the Water Processor Assembly (WPA) to the potable water. The UPA and WPA use technologies commonly used on ISS for water purification, including filtration, distillation, adsorption, ion exchange, and catalytic oxidation. The primary challenge with the design and operation of the WRS has been with implementing these technologies in microgravity. The absence of gravity has created unique issues that impact the constituency of the waste streams, alter two-phase fluid dynamics, and increases the impact of particulates on system performance. NASA personnel continue to pursue upgrades to the existing design to improve reliability while also addressing their viability for missions beyond ISS.

Laser anemometry measurements of natural circulation flow in a scale model PWR reactor system. [Pressurized Water Reactor

NASA Technical Reports Server (NTRS)

Kadambi, J. R.; Schneider, S. J.; Stewart, W. A.

1986-01-01

The natural circulation of a single phase fluid in a scale model of a pressurized water reactor system during a postulated grade core accident is analyzed. The fluids utilized were water and SF6. The design of the reactor model and the similitude requirements are described. Four LDA tests were conducted: water with 28 kW of heat in the simulated core, with and without the participation of simulated steam generators; water with 28 kW of heat in the simulated core, with the participation of simulated steam generators and with cold upflow of 12 lbm/min from the lower plenum; and SF6 with 0.9 kW of heat in the simulated core and without the participation of the simulated steam generators. For the water tests, the velocity of the water in the center of the core increases with vertical height and continues to increase in the upper plenum. For SF6, it is observed that the velocities are an order of magnitude higher than those of water; however, the velocity patterns are similar.

Self-assembled biomimetic superhydrophobic CaCO3 coating inspired from fouling mineralization in geothermal water.

PubMed

Wang, Gong G; Zhu, Li Q; Liu, Hui C; Li, Wei P

2011-10-18

Inspired from fouling self-mineralization in geothermal water, a novel biomimetic cactuslike CaCO(3) coating with superhydrophobic features is reported in this letter. The structure, morphologies, and phases of the CaCO(3) coating were characterized by X-ray diffractometry, scanning electron microscopy, transmission electron microscopy, and infrared spectrophotometry. After prenucleation treatment, a continuous cactuslike CaCO(3) coating with hierarchical nano- and microstructures was self-assembled on stainless steel surfaces after immersion in simulated geothermal water at 50 °C for 48 h. After being modified with a low-surface-energy monolayer of sodium stearate, the as-prepared coating exhibited superhydrophobic properties with a water contact angle of 158.9° and a sliding angle of 2°. Therefore, this work might open up a new application field of geothermal resources and provide insight into designing multidimensional structures with functional applications, including superhydrophobic surfaces. © 2011 American Chemical Society

Under-oil superhydrophilic wetted PVDF electrospun modified membrane for continuous gravitational oil/water separation with outstanding flux.

PubMed

Obaid, M; Mohamed, Hend Omar; Yasin, Ahmed S; Yassin, Mohamed A; Fadali, Olfat A; Kim, HakYong; Barakat, Nasser A M

2017-10-15

Water in the world is becoming an increasingly scarce commodity and the membrane technology is a most effective strategy to address this issue. However, the fouling and low flux of the polymeric membrane remains the big challenges. Novel modified Polyvinylidene fluoride (PVDF) membrane was introduced, in this work, using a novel treatment technique for an electrospun polymeric PVDF membrane to be used in oil/water separation systems. The Characterizations of the modified and pristine membranes showed distinct changes in the phase and crystal structure of the membrane material as well as the wettability. The modification process altered the surface morphology and structure of the membrane by forming hydrophilic microspheres on the membrane surface. Therefore, the proposed treatment converts the membrane from highly hydrophobic to be a superhydrophilic under-oil when wetted with water. Accordingly, in the separation of oil/water mixtures, the modified membrane can achieve an outstanding flux of 20664 L/m 2 . hr under gravity, which is higher than the pristine membrane by infinite times. Moreover, in the separation of the emulsion, a high flux of 2727 L/m 2 . h was achieved. The results exhibited that the modified membrane can treat a huge amount of oily water with a minimal energy consumption. The corresponding separation efficiencies of both of oil/water mixtures and emulsion are more than 99%. The achieved characteristics for the modified and pristine membranes could be exploited to design a novel continuous system for oil/water separation with an excellent efficiency. Copyright © 2017 Elsevier Ltd. All rights reserved.

Connecting thermodynamic and dynamical anomalies of water-like liquid-liquid phase transition in the Fermi-Jagla model

NASA Astrophysics Data System (ADS)

Higuchi, Saki; Kato, Daiki; Awaji, Daisuke; Kim, Kang

2018-03-01

We present a study using molecular dynamics simulations based on the Fermi-Jagla potential model, which is the continuous version of the mono-atomic core-softened Jagla model [J. Y. Abraham, S. V. Buldyrev, and N. Giovambattista, J. Phys. Chem. B 115, 14229 (2011)]. This model shows the water-like liquid-liquid phase transition between high-density and low-density liquids at the liquid-liquid critical point. In particular, the slope of the coexistence line becomes weakly negative, which is expected to represent one of the anomalies of liquid polyamorphism. In this study, we examined the density, dynamic, and thermodynamic anomalies in the vicinity of the liquid-liquid critical point. The boundaries of density, self-diffusion, shear viscosity, and excess entropy anomalies were characterized. Furthermore, these anomalies are connected according to Rosenfeld's scaling relationship between the excess entropy and the transport coefficients such as diffusion and viscosity. The results demonstrate the hierarchical and nested structures regarding the thermodynamic and dynamic anomalies of the Fermi-Jagla model.

A multifunctional biphasic water splitting catalyst tailored for integration with high-performance semiconductor photoanodes

NASA Astrophysics Data System (ADS)

Yang, Jinhui; Cooper, Jason K.; Toma, Francesca M.; Walczak, Karl A.; Favaro, Marco; Beeman, Jeffrey W.; Hess, Lucas H.; Wang, Cheng; Zhu, Chenhui; Gul, Sheraz; Yano, Junko; Kisielowski, Christian; Schwartzberg, Adam; Sharp, Ian D.

2017-03-01

Artificial photosystems are advanced by the development of conformal catalytic materials that promote desired chemical transformations, while also maintaining stability and minimizing parasitic light absorption for integration on surfaces of semiconductor light absorbers. Here, we demonstrate that multifunctional, nanoscale catalysts that enable high-performance photoelectrochemical energy conversion can be engineered by plasma-enhanced atomic layer deposition. The collective properties of tailored Co3O4/Co(OH)2 thin films simultaneously provide high activity for water splitting, permit efficient interfacial charge transport from semiconductor substrates, and enhance durability of chemically sensitive interfaces. These films comprise compact and continuous nanocrystalline Co3O4 spinel that is impervious to phase transformation and impermeable to ions, thereby providing effective protection of the underlying substrate. Moreover, a secondary phase of structurally disordered and chemically labile Co(OH)2 is introduced to ensure a high concentration of catalytically active sites. Application of this coating to photovoltaic p+n-Si junctions yields best reported performance characteristics for crystalline Si photoanodes.

Synthesis of Superabsorbent Polymer via Inverse Suspension Method: Effect of Carbon Filler

NASA Astrophysics Data System (ADS)

Zakaria, Munirah Ezzah Tuan; Shima Jamari, Saidatul; Ling, Yeong Yi; Ghazali, Suriati

2017-05-01

This paper studies on the effect of the addition of carbon filler towards the performance of superabsorbent polymer composite (SAPc). In this work, the SAPc was synthesized using inverse suspension polymerization method. The process involved two different solutions; dispersed phase which contains partially neutralized acrylic acid, acrylamide, APS and NN-Methylenebisacrylamide, and continuous phase which contains cyclohexane, span-80 and carbon filler (at different weight percent). The optimum SAPs and filler ratio was measured in terms of water retention in soil and characterized by Mastersizer, FTIR and SEM. Biodegradability of the polymer was determined by soil burial test and SAPc with 0.02% carbon has highest biodegradability rate. SAPc with 0.04wt% carbon showed the optimal water retention percentage among all the samples. The synthesized SAPc producing spherical shapes with parallel alignment due to the addition of carbon fiber. It can be concluded that the addition of carbon fiber able to enhance the performance of the SAP composite (SAPc).

Investigation of environmental indices from the Earth Resources Technology Satellite

NASA Technical Reports Server (NTRS)

Greeley, R. S. (Principal Investigator); Riley, E. L.; Stryker, S.; Ward, E. A.

1973-01-01

The author has identified the following significant results. Land use, quality, and air quality trends are being deduced from both ERTS-1 MSS and computer compatible tapes. The data analysis plan and the preliminary data analysis phase were conducted in January 1973. Results from these two phases are: (1) Method of analysis has been selected and checked out. (2) Land use for two dates have been generated for one test site. (3) Water quality for one date has been produced partially. (4) Air quality for three has been produced and compared with ground truth. (5) One of the two DCP stations is in operation; the second station will be installed in March 1973. Land use classification exceeds pre-launch expectations. Water quality (turbidity) is not progressing as expected. Finally, mesoscale air quality results have shown correlation with NOAA/EPA turbidity network. If air quality correlations continue to show favorable results, a rapid means of global turbidity may be available from ERTS-1 MSS observations.

Use of an intact core and stable-metal isotopes to examine leaching characteristics of a fluvial tailings deposit

USGS Publications Warehouse

Ranville, James F.; Smith, Kathleen S.; Lamothe, Paul J.; Jackson, Brian P.; Walton-Day, Katherine

2003-01-01

In this paper, we use Cd as an example of the utility of stable-metal isotopes in geochemical studies. In the case of Cd, after the core was partially saturated, the 111Cd spike was released as evidenced by a change in the Cd isotope ratios in the effluent. This release continued during the fully saturated leaching phase, however, the total Cd concentration did not increase. These results suggest that the 111Cd spike was retained inside the core during the unsaturated leaching phase, and only partially released as reducing conditions developed. Results from this core-leaching experiment indicate there is a large reservoir of water-soluble material within the fluvial tailings deposit, which yields elevated metal concentrations and high acidity, and which may degrade adjacent ground- and surface-water quality. Use of stable metal isotopes in this study facilitated the determination of different metal-retention processes, metal-release processes, and metal sources in the fluvial tailings deposit in response to changing geochemical conditions.

A new seamless, high-resolution digital elevation model of the San Francisco Bay-Delta Estuary, California

USGS Publications Warehouse

Fregoso, Theresa A.; Wang, Rueen-Fang; Ateljevich, Eli; Jaffe, Bruce E.

2017-06-14

Climate change, sea-level rise, and human development have contributed to the changing geomorphology of the San Francisco Bay - Delta (Bay-Delta) Estuary system. The need to predict scenarios of change led to the development of a new seamless, high-resolution digital elevation model (DEM) of the Bay – Delta that can be used by modelers attempting to understand potential future changes to the estuary system. This report details the three phases of the creation of this DEM. The first phase took a bathymetric-only DEM created in 2005 by the U.S. Geological Survey (USGS), refined it with additional data, and identified areas that would benefit from new surveys. The second phase began a USGS collaboration with the California Department of Water Resources (DWR) that updated a 2012 DWR seamless bathymetric/topographic DEM of the Bay-Delta with input from the USGS and modifications to fit the specific needs of USGS modelers. The third phase took the work from phase 2 and expanded the coverage area in the north to include the Yolo Bypass up to the Fremont Weir, the Sacramento River up to Knights Landing, and the American River up to the Nimbus Dam, and added back in the elevations for interior islands. The constant evolution of the Bay-Delta will require continuous updates to the DEM of the Delta, and there still are areas with older data that would benefit from modern surveys. As a result, DWR plans to continue updating the DEM.

N-Consecutive-Phase Encoder

NASA Technical Reports Server (NTRS)

Divsalar, Dariush; Lee, Ho-Kyoung; Weber, Charles

1995-01-01

N-consecutive-phase encoder (NCPE) is conceptual encoder for generating alphabet of N consecutive full-response continuous-phase-modulation (CPM) signals. Enables use of binary preencoder of higher rate than used with simple continuous-phase encoder (CPE). NCPE makes possible to achieve power efficiencies and bandwidth efficiencies greater than conventional trellis coders with continuous-phase frequency-shift keying (CPFSK).

Temporal resolution required for accurate evaluation of the interplay effect in spot scanning proton therapy

NASA Astrophysics Data System (ADS)

Seo, Jeongmin; Han, Min Cheol; Yeom, Yeon Soo; Lee, Hyun Su; Kim, Chan Hyeong; Jeong, Jong Hwi; Kim, SeongHoon

2017-04-01

In proton therapy, the spot scanning method is known to suffer from the interplay effect induced from the independent movements of the proton beam and the organs in the patient during the treatment. To study the interplay effect, several investigators have performed four-dimensional (4D) dose calculations with some limited temporal resolutions (4 or 10 phases per respiratory cycle) by using the 4D computed tomography (CT) images of the patient; however, the validity of the limited temporal resolutions has not been confirmed. The aim of the present study is to determine whether the previous temporal resolutions (4 or 10 phases per respiratory cycle) are really high enough for adequate study of the interplay effect in spot scanning proton therapy. For this study, a series of 4D dose calculations were performed with a virtual water phantom moving in the vertical direction during dose delivery. The dose distributions were calculated for different temporal resolutions (4, 10, 25, 50, and 100 phases per respiratory cycle), and the calculated dose distributions were compared with the reference dose distribution, which was calculated using an almost continuously-moving water phantom ( i.e., 1000 phases per respiratory cycle). The results of the present study show that the temporal resolutions of 4 and 10 phases per respiratory cycle are not high enough for an accurate evaluation of the interplay effect for spot scanning proton therapy. The temporal resolution should be at least 14 and 17 phases per respiratory cycle for 10-mm and 20-mm movement amplitudes, respectively, even for rigid movement ( i.e., without deformation) of the homogeneous water phantom considered in the present study. We believe that even higher temporal resolutions are needed for an accurate evaluation of the interplay effect in the human body, in which the organs are inhomogeneous and deform during movement.

Phase plate technology for laser marking of magnetic discs

DOEpatents

Neuman, Bill; Honig, John; Hackel, Lloyd; Dane, C. Brent; Dixit, Shamasundar

1998-01-01

An advanced design for a phase plate enables the distribution of spots in arbitrarily shaped patterns with very high uniformity and with a continuously or near-continuously varying phase pattern. A continuous phase pattern eliminates large phase jumps typically expected in a grating that provides arbitrary shapes. Large phase jumps increase scattered light outside of the desired pattern, reduce efficiency and can make the grating difficult to manufacture. When manufacturing capabilities preclude producing a fully continuous grating, the present design can be easily adapted to minimize manufacturing errors and maintain high efficiencies. This continuous grating is significantly more efficient than previously described Dammann gratings, offers much more flexibility in generating spot patterns and is easier to manufacture and replicate than a multi-level phase grating.

Streamflow and water-quality data for Lake Purdy and its tributaries, Jefferson and Shelby Counties, Alabama, water years 1987-91

USGS Publications Warehouse

Stricklin, V.E.

1993-01-01

An investigation was begun in North Carolina in 1988 to: (1) quantify nutrient, sediment, and freshwater loadings in canals that collect drainage from cropland field ditches; (2) determine the effects of tide gates and flashboard risers on these loadings and on receiving-water quality; and (3) characterize the effects of drainage on the salinity regime of a tidal creek. Data were collected in three canals in Hyde County, three canals in Beaufort County, and in Campbell Creek, which receives drainage directly from two of the Beaufort County canals. Water-control structures were placed on two of the six canals near the beginning of the investigation. Following about 2 years of data collection, control structures were placed on the remaining four canals. Hydrologic and water-quality data are presented for each of the study sites for the period of October 1990 through May 1992. Data presented in this report cover the second phase of the investigation after the installation of water-control structures in the six drainage canals. Following a description of the study sites and data-collection methods, data are presented for five of the drainage canals and Campbell Creek. Data collection was discontinued at one of the Beaufort County sites after the first phase of the investigation. The data collected include: (1) daily values of accumulated precipitation; (2) water-level statistics; (3) daily mean values of discharge in the canals; (4) biweekly water-quality measurements and sample analyses; (5) storm-event water-quality measurements and sample analyses; (6) continuous records of specific conductance in the canals; (7) vertical profiles of salinity in Campbell Creek; and (8) daily mean values of salinity at five sites in Campbell Creek.

Method for in situ characterization of a medium of dispersed matter in a continuous phase

DOEpatents

Kaufman, Eric N.

1995-01-01

A method for in situ characterization of a medium of a dispersed phase in a continuous phase, including the steps of adding a fluorescent dye to one phase capable of producing fluorescence therein when the fluorescent dye is optically excited, optically exciting the fluorescent dye at a wavelength to produce fluorescence in the one phase, and monitoring the fluorescence to distinguish the continuous phase from the dispersed phase.

Development of "ultrasound-assisted dynamic extraction" and its combination with CCC and CPC for simultaneous extraction and isolation of phytochemicals.

PubMed

Zhang, Yuchi; Liu, Chunming; Li, Jing; Qi, Yanjuan; Li, Yuchun; Li, Sainan

2015-09-01

A new method for the extraction of medicinal herbs termed ultrasonic-assisted dynamic extraction (UADE) was designed and evaluated. This technique was coupled with counter-current chromatography (CCC) and centrifugal partition chromatography (CPC) and then applied to the continuous extraction and online isolation of chemical constituents from Paeonia lactiflora Pall (white peony) roots. The mechanical parameters, including the pitch and diameter of the shaft, were optimized by means of mathematical modeling. Furthermore, the configuration and mechanism of online UADE coupled with CCC and CPC were elaborated. The stationary phases of the two-phase solvent systems from CCC and CPC were utilized as the UADE solution. The extraction solution was pumped into the sample loop and then introduced into the CCC column; the target compounds were eluted with the lower aqueous phase of the two-phase solvent system. During the CCC separation, the extraction solution was continuously fed in the sample loop by turning the ten-port valve; the extraction solution was then pumped into the CPC column and eluted by the mobile phase of the two-phase solvent system mentioned above. When the first cycle of the UADE/CCC/CPC was completed, the second cycle experiment could be carried out, and so on. Four target compounds (albiflorin, benzoylpaeoniflorin, paeoniflorin, and galloylpaeoniflorin) with purities above 94.96% were successfully extracted and isolated online using the two-phase solvent system comprising ethyl acetate-n-butanol-ethanol-water (1:3.5:2:4.5, v/v/v/v). Compared with conventional extraction methods, the instrumental setup of the present method offers the advantages of automation and systematic extraction and isolation of natural products. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.

Techniques for active passivation

DOEpatents

Roscioli, Joseph R.; Herndon, Scott C.; Nelson, Jr., David D.

2016-12-20

In one embodiment, active (continuous or intermittent) passivation may be employed to prevent interaction of sticky molecules with interfaces inside of an instrument (e.g., an infrared absorption spectrometer) and thereby improve response time. A passivation species may be continuously or intermittently applied to an inlet of the instrument while a sample gas stream is being applied. The passivation species may have a highly polar functional group that strongly binds to either water or polar groups of the interfaces, and once bound presents a non-polar group to the gas phase in order to prevent further binding of polar molecules. The instrument may be actively used to detect the sticky molecules while the passivation species is being applied.

Controlled double emulsification utilizing 3D PDMS microchannels

NASA Astrophysics Data System (ADS)

Chang, Fu-Che; Su, Yu-Chuan

2008-06-01

This paper presents a PDMS emulsification device that is capable of generating water-in-oil-in-water double emulsions in a controlled manner. Specially designed 3D microchannels are utilized to steer the independently driven water- and oil-phase flows (especially to restrict the attachment of the middle oil-phase flow on the channel surfaces), and to break the continuous flows into monodisperse double emulsions. In addition to channel geometries and fluid flow rates, surfactants and osmotic agents are employed to facilitate the breakup process and stabilize the resulting emulsion structures. In the prototype demonstration, two-level SU-8 molds were fabricated to duplicate PDMS microstructures, which were surface treated and bonded irreversibly to form 3D microchannels. Throughout the emulsification trials, dripping was intentionally induced to generate monodisperse double emulsions with single or multiple aqueous droplets inside each oil drop. It is found that the overall and core sizes of the resulting double emulsions could be adjusted independently, mainly by varying the outer and inner fluid flow rates, respectively. As such, the presented double emulsification device could potentially realize the controllability on emulsion structure and size distribution, which is desired for a variety of biological and pharmaceutical applications.

Numerical modeling of NI-monitored 3D infiltration experiment

NASA Astrophysics Data System (ADS)

Dohnal, Michal; Dusek, Jaromir; Snehota, Michal; Sacha, Jan; Vogel, Tomas; Votrubova, Jana

2014-05-01

It is well known that the temporal changes of saturated hydraulic conductivity caused by the occurrence of air phase discontinuities often play an important role in water flow and solute transport experiments. In the present study, a series of infiltration-outflow experiments was conducted to test several working hypotheses about the mechanism of air phase trapping. The experiments were performed on a porous sample with artificial internal structure, using three sandy materials with contrasting hydraulic properties. The sample was axially symmetric with continuous preferential pathways and separate porous matrix blocks (the sample was 3.4 cm in diameter and 8.8 cm high). The infiltration experiments were monitored by neutron imaging (NI). The NI data were then used to quantify the water content of the selected sample regions. The flow regime in the sample was studied using a three-dimensional model based on Richards' equation. The equation was solved by the finite element method. The results of the numerical simulations of the infiltration experiments were compared with the measured outflow rates and with the spatial distribution of water content determined by NI. The research was supported by the Czech Science Foundation Project No. 14-03691S.

Adapalene microemulsion for transfollicular drug delivery.

PubMed

Bhatia, Gaurav; Zhou, Yingcong; Banga, Ajay K

2013-08-01

The aim of this study was to develop a microemulsion formulation of adapalene for transfollicular delivery. A pseudoternary phase diagram was developed for microemulsion consisting of oleic acid as oil phase, tween 20 as surfactant, Transcutol® as cosurfactant, and deionized water. Differential tape stripping and confocal laser scanning microscopy were performed to determine the penetration of microemulsion through hair follicles. Transmission electron microscopy, dynamic light scattering, polarizing light microscopy, and differential scanning calorimetry were performed to characterize the microstructures of microemulsion. The pH and viscosity of the microemulsions were also determined. Permeation studies were carried out in vitro on porcine ear skin over a period of 24 h using Franz diffusion cells. The drug penetration in the hair follicles increased from 0.109 ± 0.03 to 0.292 ± 0.094 μg, as the microstructure of microemulsion shifted from oil-in-water to bi-continuous, with increase in water content of microemulsion. Confocal laser scanning microscopy images suggested that hair follicles provided the path for transfollicular permeation of adapalene microemulsion. These results suggest that microemulsion penetrated through hair follicles and are promising for transfollicular drug delivery. Copyright © 2013 Wiley Periodicals, Inc.

Application of the Baxter model for hard-spheres with surface adhesion to SANS data for the U(VI) - HNO{sub 3}, TBP-n-dodecane system.

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

Chiarizia, R.; Nash, K. L.; Jensen, M. P.

2003-11-11

Small-angle neutron scattering (SANS) data for the tri-n-butyl phosphate (TBP)-n-dodecane, HNO{sub 3}-UO{sub 2}(NO{sub 3}){sub 2} solvent extraction system have been interpreted using the Baxter model for hard spheres with surface adhesion. The increase in the scattering intensity in the low Q range observed when increasing amounts of HNO{sub 3} or UO{sub 2}(NO{sub 3}){sub 2} are transferred into the organic phase has been interpreted as arising from interactions between solute particles. The SANS data have been reproduced using a 12--16 {angstrom} diameter of the hard sphere, d{sub hs}, and a 5.6k{sub B}T-7.1k{sub B}T stickiness parameter, {tau}{sup -1}. When in contact withmore » an aqueous phase, TBP in n-dodecane forms small reverse micelles containing three TBP molecules. Upon extraction of water, HNO{sub 3}, and UO{sub 2}(NO{sub 3}){sub 2}, the swollen micelles interact through attractive forces between their polar cores with a potential energy of about 2k{sub B}T and an effective Hamaker constant of about 4k{sub B}T. The intermicellar attraction, under suitable conditions, leads to third-phase formation. Upon phase splitting, most of the solutes in the original organic phase (water, TBP, HNO{sub 3}, and UO{sub 2}(NO{sub 3}){sub 2}) separate in a continuous phase containing interspersed layers of n-dodecane.« less

Effect of potassium chloride supplementation in drinking water on broiler performance under heat stress conditions.

PubMed

Ahmad, T; Khalid, T; Mushtaq, T; Mirza, M A; Nadeem, A; Babar, M E; Ahmad, G

2008-07-01

The effect of water supplementation of KCl on performance of heat-stressed Hubbard broilers was evaluated in the present experiment. The 3 experimental treatments (i.e., control, 0.3 and 0.6% KCl) were allocated to 3 replicates of 15 birds each. The control group was kept on dugout tap water, whereas the other 2 groups were supplied water supplemented with 0.3 and 0.6% KCl (wt/vol) by supplementing 3 and 6 g of KCl, respectively, per liter of drinking water. Broilers were provided ad libitum access to feed and water for the experimental period of 7 to 42 d of age and kept in open-sided house. The birds were reared under continuous thermostress (minimum 28.2 +/- 1.02 and maximum 37.5 +/- 0.78 degrees C) environment. Supplementing drinking water with 0.6% KCl reduced panting-phase blood pH to 7.31 and significantly increased live BW gain by 14.5 (P = 0.036) and 7.9% (P = 0.029) at 28 and 42 d of age, respectively, relative to control. An improved (P = 0.04) feed:gain and lowered body temperature were noted in groups supplemented with 0.6% KCl as compared with control and 0.3% KCl. Enhanced physiological adaptation with 0.6% KCl was evidenced by a more favorable pH during the panting phase in the present study. These findings demonstrated a possibility of better broiler live performance through KCl supplementation under conditions of severe heat stress (35 to 38 degrees C).

Freezing-induced cellular and membrane dehydration in the presence of cryoprotective agents.

PubMed

Akhoondi, Maryam; Oldenhof, Harriëtte; Sieme, Harald; Wolkers, Willem F

2012-09-01

FTIR and cryomicroscopy have been used to study mouse embryonic fibroblast cells (3T3) during freezing in the absence and presence of DMSO and glycerol. The results show that cell volume changes as observed by cryomicroscopy typically end at temperatures above -15°C, whereas membrane phase changes may continue until temperatures as low as -30°C. This implies that cellular dehydration precedes dehydration of the bound water surrounding the phospholipid head groups. Both DMSO and glycerol increase the membrane hydraulic permeability at subzero temperature and reduce the activation energy for water transport. Cryoprotective agents facilitate dehydration to continue at low subzero temperatures thereby decreasing the incidence of intracellular ice formation. The increased subzero membrane hydraulic permeability likely plays an important role in the cryoprotective action of DMSO and glycerol. In the presence of DMSO water permeability was found to be greater compared to that in the presence of glycerol. Two temperature regimes were identified in an Arrhenius plot of the membrane hydraulic permeability. The activation energy for water transport at temperature ranging from 0 to -10°C was found to be greater than that below -10°C. The non-linear Arrhenius behavior of Lp has been implemented in the water transport model to simulate cell volume changes during freezing. At a cooling rate of 1°C min(-1), ∼5% of the initial osmotically active water volume is trapped inside the cells at -30°C.

Four phases of the Flint Water Crisis: Evidence from blood lead levels in children.

PubMed

Zahran, Sammy; McElmurry, Shawn P; Sadler, Richard C

2017-08-01

The Flint Water Crisis (FWC) is divisible into four phases of child water-lead exposure risk: Phase A) before the switch in water source to the Flint River (our baseline); Phase B) after the switch in water source, but before boil water advisories; Phase C) after boil water advisories, but before the switch back to the baseline water source of the Detroit Water and Sewerage Department (DWSD); and Phase D) after the switch back to DWSD. The objective of this work is to estimate water-lead attributable movements in child blood lead levels (BLLs) that correspond with the four phases in the FWC. With over 21,000 geo-referenced and time-stamped blood lead samples from children in Genesee County drawn from January 01, 2013 to July 19, 2016, we develop a series of quasi-experimental models to identify the causal effect of water-lead exposure on child BLLs in Flint. We find that the switch in water source (transitioning from phase A to B) caused mean BLLs to increase by about 0.5μg/dL, and increased the likelihood of a child presenting with a BLL ≥ 5μg/dL by a factor of 1.91-3.50, implying an additional 561 children exceeding 5μg/dL. We conservatively estimate cohort social costs (through lost earnings alone) of this increase in water-lead exposed children at $65 million, contrasted with expected annual savings of $2 million from switching water source. On the switch from Phase B to C, we find BLLs decreased about 50% from their initial rise following boil water advisories and subsequent water avoidance behaviors by households. Finally, the return to the baseline source water (Phase D) returned child BLLs to pre-FWC levels further implicating water-lead exposure as a causal source of child BLLs throughout the FWC. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Measurement of the initial phase of ozone decomposition in water and wastewater by means of a continuous quench-flow system: application to disinfection and pharmaceutical oxidation.

PubMed

Buffle, Marc-Olivier; Schumacher, Jochen; Salhi, Elisabeth; Jekel, Martin; von Gunten, Urs

2006-05-01

Due to a lack of adequate experimental techniques, the kinetics of the first 20s of ozone decomposition in natural water and wastewater is still poorly understood. Introducing a continuous quench-flow system (CQFS), measurements starting 350 ms after ozone addition are presented for the first time. Very high HO. to O3 exposures ratios (Rct=integralHO.dt/integralO3dt) reveal that the first 20s of ozonation present oxidation conditions that are similar to ozone-based advanced oxidation processes (AOP). The oxidation of carbamazepine could be accurately modeled using O3 and HO. exposures measured with CQFS during wastewater ozonation. These results demonstrate the applicability of bench scale determined second-order rate constants for wastewater ozonation. Important degrees of pharmaceutical oxidation and microbial inactivation are predicted, indicating that a significant oxidation potential is available during wastewater ozonation, even when ozone is entirely decomposed in the first 20s.

Ethanol fermentation integrated with PDMS composite membrane: An effective process.

PubMed

Fu, Chaohui; Cai, Di; Hu, Song; Miao, Qi; Wang, Yong; Qin, Peiyong; Wang, Zheng; Tan, Tianwei

2016-01-01

The polydimethylsiloxane (PDMS) membrane, prepared in water phase, was investigated in separation ethanol from model ethanol/water mixture and fermentation-pervaporation integrated process. Results showed that the PDMS membrane could effectively separate ethanol from model solution. When integrated with batch ethanol fermentation, the ethanol productivity was enhanced compared with conventional process. Fed-batch and continuous ethanol fermentation with pervaporation were also performed and studied. 396.2-663.7g/m(2)h and 332.4-548.1g/m(2)h of total flux with separation factor of 8.6-11.7 and 8-11.6, were generated in the fed-batch and continuous fermentation with pervaporation scenario, respectively. At the same time, high titre ethanol production of ∼417.2g/L and ∼446.3g/L were also achieved on the permeate side of membrane in the two scenarios, respectively. The integrated process was environmental friendly and energy saving, and has a promising perspective in long-terms operation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Phase plate technology for laser marking of magnetic discs

DOEpatents

Neuman, B.; Honig, J.; Hackel, L.; Dane, C.B.; Dixit, S.

1998-10-27

An advanced design for a phase plate enables the distribution of spots in arbitrarily shaped patterns with very high uniformity and with a continuously or near-continuously varying phase pattern. A continuous phase pattern eliminates large phase jumps typically expected in a grating that provides arbitrary shapes. Large phase jumps increase scattered light outside of the desired pattern, reduce efficiency and can make the grating difficult to manufacture. When manufacturing capabilities preclude producing a fully continuous grating, the present design can be easily adapted to minimize manufacturing errors and maintain high efficiencies. This continuous grating is significantly more efficient than previously described Dammann gratings, offers much more flexibility in generating spot patterns and is easier to manufacture and replicate than a multi-level phase grating. 3 figs.

Using noble gases measured in spring discharge to trace hydrothermal processes in the Norris Geyser Basin, Yellowstone National Park, U.S.A.

USGS Publications Warehouse

Gardner, W.P.; Susong, D.D.; Solomon, D.K.; Heasler, H.P.

2010-01-01

Dissolved noble gas concentrations in springs are used to investigate boiling of hydrothermal water and mixing of hydrothermal and shallow cool water in the Norris Geyser Basin area. Noble gas concentrations in water are modeled for single stage and continuous steam removal. Limitations on boiling using noble gas concentrations are then used to estimate the isotopic effect of boiling on hydrothermal water, allowing the isotopic composition of the parent hydrothermal water to be determined from that measured in spring. In neutral chloride springs of the Norris Geyser Basin, steam loss since the last addition of noble gas charged water is less than 30% of the total hydrothermal discharge, which results in an isotopic shift due to boiling of ?? 2.5% ??D. Noble gas concentrations in water rapidly and predictably change in dual phase systems, making them invaluable tracers of gas-liquid interaction in hydrothermal systems. By combining traditional tracers of hydrothermal flow such as deuterium with dissolved noble gas measurements, more complex hydrothermal processes can be interpreted. ?? 2010 Elsevier B.V.

Dynamic Performance of High Bypass Ratio Turbine Engines With Water Ingestion

NASA Technical Reports Server (NTRS)

Murthy, S. N. B.

1996-01-01

The research on dynamic performance of high bypass turbofan engines includes studies on inlets, turbomachinery and the total engine system operating with air-water mixture; the water may be in vapor, droplet, or film form, and their combinations. Prediction codes (WISGS, WINCOF, WINCOF-1, WINCLR, and Transient Engine Performance Code) for performance changes, as well as changes in blade-casing clearance, have been established and demonstrated in application to actual, generic engines. In view of the continuous changes in water distribution in turbomachinery, the performance of both components and the total engine system must be determined in a time-dependent mode; hence, the determination of clearance changes also requires a time-dependent approach. In general, the performance and clearances changes cannot be scaled either with respect to operating or ingestion conditions. Removal of water prior to phase change is the most effective means of avoiding ingestion effects. Sufficient background has been established to perform definitive, full scale tests on a set of components and a complete engine to establish engine control and operability with various air-water vapor-water mixtures.

Changes of Geo-Runoff Components in Russian Arctic Rivers

NASA Astrophysics Data System (ADS)

Groisman, P. Y.; Georgiadi, A.; Kashutina, E.; Milyukova, I.

2017-12-01

Long-term phases of changes in naturalized components of the geo-runoff (streamflow, heat flow and suspended sediment yield) of Russian Arctic Rivers during the period of observation (from 1930-1940 till 2000s) were revealed on the basis of normalized cumulative curves. Their characteristics and the effects of impact of anthropogenic factors are evaluated. Since 1930-1940s till the beginning of the 21st century, the naturalized annual and seasonal river runoff in the largest river basins (Ob', Yenisei, Lena) was characterized by two main long-term phases of its changes. The phase of decreased runoff (since the 1930-1940s) was replaced in the 1970-1980s by a long-term phase of increased streamflow. The duration of phases was several decades and are characterized by significant runoff differences. In the long-term variations of the heat flow of the Ob, Yenisei, Lena, Northern Dvina and Pechora also were found two major long-term phases. The phase of the heat flow decrease, which began in 1930-1940-ies and lasted for 35-55 years, was replaced in 1970-1980 by 20-year phase of its increase (except the Yenisei, where this phase began in the late 1990s.) and has continued until now. Similar long-term phases are observed for river water temperature of considered rivers. Differences in heat flow reaches 20% during the phase of its increased and decreased values for the Northern Dvina and the Yenisei Rivers, but for other rivers they are not higher than 10%. Long-term changes of annual suspended sediment yield for the Yenisei and Lena Rivers are also characterized by two major long-term phases, which replaced each another in the 1970-1990. Differences in the suspended sediment yield during the increase and decrease phases reach 40% for Lena, whereas for Yenisei they are substantially less (10%). Anthropogenic factors (mainly water reservoirs) have significantly changed the characteristics of the long-term phases on the Yenisei River while their impact is not significant on other rivers. The long-term phases of decrease and increase of "conditionally natural" components of Arctic Rivers of Russia geo-runoff are closely associated with the indices zonal atmospheric air transport intensity.

Investigation of Cooling Water Injection into Supersonic Rocket Engine Exhaust

NASA Astrophysics Data System (ADS)

Jones, Hansen; Jeansonne, Christopher; Menon, Shyam

2017-11-01

Water spray cooling of the exhaust plume from a rocket undergoing static testing is critical in preventing thermal wear of the test stand structure, and suppressing the acoustic noise signature. A scaled test facility has been developed that utilizes non-intrusive diagnostic techniques including Focusing Color Schlieren (FCS) and Phase Doppler Particle Anemometry (PDPA) to examine the interaction of a pressure-fed water jet with a supersonic flow of compressed air. FCS is used to visually assess the interaction of the water jet with the strong density gradients in the supersonic air flow. PDPA is used in conjunction to gain statistical information regarding water droplet size and velocity as the jet is broken up. Measurement results, along with numerical simulations and jet penetration models are used to explain the observed phenomena. Following the cold flow testing campaign a scaled hybrid rocket engine will be constructed to continue tests in a combusting flow environment similar to that generated by the rocket engines tested at NASA facilities. LaSPACE.

Status of surface-water modeling in the U.S. Geological Survey

USGS Publications Warehouse

Jennings, Marshall E.; Yotsukura, Nobuhiro

1979-01-01

The U.S. Geological Survey is active in the development and use of models for the analysis of various types of surface-water problems. Types of problems for which models have been, or are being developed, include categories such as the following: (1)specialized hydraulics, (2)flow routing in streams, estuaries, lakes, and reservoirs, (3) sedimentation, (4) transport of physical, chemical, and biological constituents, (5) surface exchange of heat and mass, (6) coupled stream-aquifer flow systems, (7) physical hydrology for rainfall-runoff relations, stream-system simulations, channel geometry, and water quality, (8) statistical hydrology for synthetic streamflows, floods, droughts, storage, and water quality, (9) management and operation problems, and (10) miscellaneous hydrologic problems. Following a brief review of activities prior to 1970, the current status of surface-water modeling is given as being in a developmental, verification, operational, or continued improvement phase. A list of recently published selected references, provides useful details on the characteristics of models.

Predicting Droplet Formation on Centrifugal Microfluidic Platforms

NASA Astrophysics Data System (ADS)

Moebius, Jacob Alfred

Centrifugal microfluidics is a widely known research tool for biological sample and water quality analysis. Currently, the standard equipment used for such diagnostic applications include slow, bulky machines controlled by multiple operators. These machines can be condensed into a smaller, faster benchtop sample-to-answer system. Sample processing is an important step taken to extract, isolate, and convert biological factors, such as nucleic acids or proteins, from a raw sample to an analyzable solution. Volume definition is one such step. The focus of this thesis is the development of a model predicting monodispersed droplet formation and the application of droplets as a technique for volume definition. First, a background of droplet microfluidic platforms is presented, along with current biological analysis technologies and the advantages of integrating such technologies onto microfluidic platforms. Second, background and theories of centrifugal microfluidics is given, followed by theories relevant to droplet emulsions. Third, fabrication techniques for centrifugal microfluidic designs are discussed. Finally, the development of a model for predicting droplet formation on the centrifugal microfluidic platform are presented for the rest of the thesis. Predicting droplet formation analytically based on the volumetric flow rates of the continuous and dispersed phases, the ratios of these two flow rates, and the interfacial tension between the continuous and dispersed phases presented many challenges, which will be discussed in this work. Experimental validation was completed using continuous phase solutions of different interfacial tensions. To conclude, prospective applications are discussed with expected challenges.

Leaching of cadmium and tellurium from cadmium telluride (CdTe) thin-film solar panels under simulated landfill conditions.

PubMed

Ramos-Ruiz, Adriana; Wilkening, Jean V; Field, James A; Sierra-Alvarez, Reyes

2017-08-15

A crushed non-encapsulated CdTe thin-film solar cell was subjected to two standardized batch leaching tests (i.e., Toxicity Characteristic Leaching Procedure (TCLP) and California Waste Extraction Test (WET)) and to a continuous-flow column test to assess cadmium (Cd) and tellurium (Te) dissolution under conditions simulating the acidic- and the methanogenic phases of municipal solid waste landfills. Low levels of Cd and Te were solubilized in both batch leaching tests (<8.2% and <3.6% of added Cd and Te, respectively). On the other hand, over the course of 30days, 73% of the Cd and 21% of the Te were released to the synthetic leachate of a continuous-flow column simulating the acidic landfill phase. The dissolved Cd concentration was 3.24-fold higher than the TCLP limit (1mgL -1 ), and 650-fold higher than the maximum contaminant level established by the US-EPA for this metal in drinking water (0.005mgL -1 ). In contrast, the release of Cd and Te to the effluent of the continuous-flow column simulating the methanogenic phase of a landfill was negligible. The remarkable difference in the leaching behavior of CdTe in the columns is related to different aqueous pH and redox conditions promoted by the microbial communities in the columns, and is in agreement with thermodynamic predictions. Copyright © 2017 Elsevier B.V. All rights reserved.

Arsenic chemistry in soils and sediments

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

Fendorf, S.; Nico, P.; Kocar, B.D.

2009-10-15

Arsenic is a naturally occurring trace element that poses a threat to human and ecosystem health, particularly when incorporated into food or water supplies. The greatest risk imposed by arsenic to human health results from contamination of drinking water, for which the World Health Organization recommends a maximum limit of 10 {micro}g L{sup -1}. Continued ingestion of drinking water having hazardous levels of arsenic can lead to arsenicosis and cancers of the bladder, skin, lungs and kidneys. Unfortunately, arsenic tainted drinking waters are a global threat and presently having a devastating impact on human health within Asia. Nearly 100 millionmore » people, for example, are presently consuming drinking water having arsenic concentrations exceeding the World Health Organization's recommended limit (Ahmed et al., 2006). Arsenic contamination of the environment often results from human activities such as mining or pesticide application, but recently natural sources of arsenic have demonstrated a devastating impact on water quality. Arsenic becomes problematic from a health perspective principally when it partitions into the aqueous rather than the solid phase. Dissolved concentrations, and the resulting mobility, of arsenic within soils and sediments are the combined result of biogeochemical processes linked to hydrologic factors. Processes favoring the partitioning of As into the aqueous phase, potentially leading to hazardous concentrations, vary extensively but can broadly be grouped into four categories: (1) ion displacement, (2) desorption (or limited sorption) at pH values > 8.5, (3) reduction of arsenate to arsenite, and (4) mineral dissolution, particularly reductive dissolution of Fe and Mn (hydr)oxides. Although various processes may liberate arsenic from solids, a transition from aerobic to anaerobic conditions, and commensurate arsenic and iron/manganese reduction, appears to be a dominant, but not exclusive, means by which high concentrations of dissolved arsenic are generated. Within the subsequent sections of this chapter, we explore and describe the biological and chemical processes that control the partitioning of arsenic between the solid and aqueous phase.« less

Deposition Nucleation or Pore Condensation and Freezing?

NASA Astrophysics Data System (ADS)

David, Robert O.; Mahrt, Fabian; Marcolli, Claudia; Fahrni, Jonas; Brühwiler, Dominik; Lohmann, Ulrike; Kanji, Zamin A.

2017-04-01

Ice nucleation plays an important role in moderating Earth's climate and precipitation formation. Over the last century of research, several mechanisms for the nucleation of ice have been identified. Of the known mechanisms for ice nucleation, only deposition nucleation occurs below water saturation. Deposition nucleation is defined as the formation of ice from supersaturated water vapor on an insoluble particle without the prior formation of liquid. However, recent work has found that the efficiency of so-called deposition nucleation shows a dependence on the homogeneous freezing temperature of water even though no liquid phase is presumed to be present. Additionally, the ability of certain particles to nucleate ice more efficiently after being pre-cooled (pre-activation) raises questions on the true mechanism when ice nucleation occurs below water saturation. In an attempt to explain the dependence of the efficiency of so-called deposition nucleation on the onset of homogeneous freezing of liquid water, pore condensation and freezing has been proposed. Pore condensation and freezing suggests that the liquid phase can exist under sub-saturated conditions with respect to liquid in narrow confinements or pores due to the inverse Kelvin effect. Once the liquid-phase condenses, it is capable of nucleating ice either homogeneously or heterogeneously. The role of pore condensation and freezing is assessed in the Zurich Ice Nucleation Chamber, a continuous flow diffusion chamber, using spherical nonporous and mesoporous silica particles. The mesoporous silica particles have a well-defined particle size range of 400 to 600nm with discreet pore sizes of 2.5, 2.8, 3.5 and 3.8nm. Experiments conducted between 218K and 238K show that so-called deposition nucleation only occurs below the homogenous freezing temperature of water and is highly dependent on the presence of pores and their size. The results strongly support pore condensation and freezing, questioning the role of deposition nucleation as an ice nucleation pathway.

Formation of hollow silica nanospheres by reverse microemulsion

NASA Astrophysics Data System (ADS)

Lin, Cheng-Han; Chang, Jen-Hsuan; Yeh, Yi-Qi; Wu, Si-Han; Liu, Yi-Hsin; Mou, Chung-Yuan

2015-05-01

Uniform hollow silica nanospheres (HSNs) synthesized with reverse microemulsion have great application potential as nanoreactors because enzymes or nanocatalysts can be easily encapsulated de novo in synthesis. Water-in-oil (w/o) reverse microemulsions comprising the polymeric surfactant polyoxyethylene (5) isooctylphenyl ether (Igepal CA-520), ammonia and water in a continuous oil phase (alkanes) coalesce into size-tunable silica nanoparticles via diffusion aggregation after the introduction of silica precursors. Here, we elucidate in detail the growth mechanism for silica nanoparticles via nucleation of ammonium-catalyzed silica oligomers from tetraethylorthosilicate (TEOS) and nanoporous aminopropyltrimethoxy silane (APTS) in the reverse microemulsion system. The formation pathway was studied in situ with small-angle X-ray scattering (SAXS). We find a four-stage process showing a sigmoidal growth behavior in time with a crossover from the induction period, early nucleation stage, coalescence growth and a final slowing down of growth. Various characterizations (TEM, N2 isotherm, dynamic light scattering, zeta potential, NMR, elemental analysis) reveal the diameters, scattering length density (SLD), mesoporosity, surface potentials and chemical compositions of the HSNs. Oil phases of alkanes with different alkyl chains are systematically employed to tune the sizes of HSNs by varying oil molar volumes, co-solvent amounts or surfactant mixture ratios. Silica condensation is incomplete in the core region, with the silica source of TEOS and APTS leading to the hollow silica nanosphere after etching with warm water.Uniform hollow silica nanospheres (HSNs) synthesized with reverse microemulsion have great application potential as nanoreactors because enzymes or nanocatalysts can be easily encapsulated de novo in synthesis. Water-in-oil (w/o) reverse microemulsions comprising the polymeric surfactant polyoxyethylene (5) isooctylphenyl ether (Igepal CA-520), ammonia and water in a continuous oil phase (alkanes) coalesce into size-tunable silica nanoparticles via diffusion aggregation after the introduction of silica precursors. Here, we elucidate in detail the growth mechanism for silica nanoparticles via nucleation of ammonium-catalyzed silica oligomers from tetraethylorthosilicate (TEOS) and nanoporous aminopropyltrimethoxy silane (APTS) in the reverse microemulsion system. The formation pathway was studied in situ with small-angle X-ray scattering (SAXS). We find a four-stage process showing a sigmoidal growth behavior in time with a crossover from the induction period, early nucleation stage, coalescence growth and a final slowing down of growth. Various characterizations (TEM, N2 isotherm, dynamic light scattering, zeta potential, NMR, elemental analysis) reveal the diameters, scattering length density (SLD), mesoporosity, surface potentials and chemical compositions of the HSNs. Oil phases of alkanes with different alkyl chains are systematically employed to tune the sizes of HSNs by varying oil molar volumes, co-solvent amounts or surfactant mixture ratios. Silica condensation is incomplete in the core region, with the silica source of TEOS and APTS leading to the hollow silica nanosphere after etching with warm water. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr01395j

InSAR constraints on soil moisture evolution after the March 2015 extreme precipitation event in Chile.

PubMed

Scott, C P; Lohman, R B; Jordan, T E

2017-07-07

Constraints on soil moisture can guide agricultural practices, act as input into weather, flooding and climate models and inform water resource policies. Space-based interferometric synthetic aperture radar (InSAR) observations provide near-global coverage, even in the presence of clouds, of proxies for soil moisture derived from the amplitude and phase content of radar imagery. We describe results from a 1.5 year-long InSAR time series spanning the March, 2015 extreme precipitation event in the hyperarid Atacama desert of Chile, constraining the immediate increase in soil moisture and drying out over the following months, as well as the response to a later, smaller precipitation event. The inferred temporal evolution of soil moisture is remarkably consistent between independent, overlapping SAR tracks covering a region ~100 km in extent. The unusually large rain event, combined with the extensive spatial and temporal coverage of the SAR dataset, present an unprecedented opportunity to image the time-evolution of soil characteristics over different surface types. Constraints on the timescale of shallow water storage after precipitation events are increasingly valuable as global water resources continue to be stretched to their limits and communities continue to develop in flood-prone areas.

Method for in situ characterization of a medium of dispersed matter in a continuous phase

DOEpatents

Kaufman, E.N.

1995-03-07

A method is described for the in situ characterization of a medium of a dispersed phase in a continuous phase, including the steps of adding a fluorescent dye to one phase capable of producing fluorescence therein when the fluorescent dye is optically excited, optically exciting the fluorescent dye at a wavelength to produce fluorescence in the one phase, and monitoring the fluorescence to distinguish the continuous phase from the dispersed phase. 2 figs.

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

USGS Publications Warehouse

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

2004-01-01

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

Water Resources Data, Florida, Water Year 2003 Volume 2B: South Florida Ground Water

USGS Publications Warehouse

Prinos, S.; Irvin, R.; Byrne, M.

2004-01-01

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

Application of Complex Fluids in Lignocellulose Processing

NASA Astrophysics Data System (ADS)

Carrillo Lugo, Carlos A.

Complex fluids such as emulsions, microemulsions and foams, have been used for different applications due to the multiplicity of properties they possess. In the present work, such fluids are introduced as effective media for processing lignocellulosic biomass. A demonstration of the generic benefits of complex fluids is presented to enhance biomass impregnation, to facilitate pretreatment for fiber deconstruction and to make compatible cellulose fibrils with hydrophobic polymers during composite manufacture. An improved impregnation of woody biomass was accomplished by application of water-continuous microemulsions. Microemulsions with high water content, > 85%, were formulated and wood samples were impregnated by wicking and capillary flooding at atmospheric pressure and temperature. Formulations were designed to effectively impregnate different wood species during shorter times and to a larger extent compared to the single components of the microemulsions (water, oil or surfactant solutions). The viscosity of the microemulsions and their interactions with cell wall constituents in fibers were critical to define the extent of impregnation and solubilization. The relation between composition and formulation variables and the extent of microemulsion penetration in different woody substrates was studied. Formulation variables such as salinity content of the aqueous phase and type of surfactant were elucidated. Likewise, composition variables such as the water-to-oil ratio and surfactant concentration were investigated. These variables affected the characteristics of the microemulsion and determined their effectiveness in wood treatment. Also, the interactions between the surfactant and the substrate had an important contribution in defining microemulsion penetration in the capillary structure of wood. Microemulsions as an alternative pretreatment for the manufacture of cellulose nanofibrils (CNFs) was also studied. Microemulsions were applied to pretreat lignin-free and lignin-containing fibers obtained from various processes. Incorporation of active agents in the microemulsion facilitated fiber pretreatment before deconstruction via grinding and microfluidization. The energy consumed during the manufacture of cellulose nanofibrils was reduced by up to 55 and 32% in the case of lignin-containing and lignin-free fibers. Moreover, such pre-treatment did not affect negatively the mechanical properties of films prepared with the produced CNF. CNF was also used to enhance the stability of normal and multiple emulsions of the water-in-oil-in-water (W/O/W) type and to prevent their creaming. This was achieved by the marked increase in viscosity of the aqueous phase in the presence CNF. Finally, water-continuous emulsions were used to prepare nanocomposite fibers containing polystyrene and CNF. The morphology of composite fibers obtained after electrospinning of emulsions incorporating polystyrene and CNF was affected by parameters such the concentration of surfactant additives present in the microemulsion and the conductivity of the aqueous phase. Overall, emulsions and microemulsions are presented as a convenient platform to improve the compatibility between polymers of different hydrophilicity, to facilitate their processing and integration in composites.

Solubilization of Tea Seed Oil in a Food-Grade Water-Dilutable Microemulsion

PubMed Central

Deng, Lingli; Que, Fei; Wei, Hewen; Xu, Guangwei; Dong, Xiaowei; Zhang, Hui

2015-01-01

Food-grade microemulsions containing oleic acid, ethanol, Tween 20, and water were formulated as a carrier system for tea seed oil (Camellia oleifera Abel.). The effect of ethanol on the phase behavior of the microemulsion system was clearly reflected in pseudo-ternary diagrams. The solubilization capacity and solubilization efficiency of tea seed oil dispersions were measured along the dilution line at a 70/30 surfactant/oil mass ratio with Tween 20 as the surfactant and oleic acid and ethanol (1:3, w/w) as the oil phase. The dispersed phase of the microemulsion (1.5% weight ratio of tea seed oil to the total amount of oil, surfactant, and tea seed oil) could be fully diluted with water without phase separation. Differential scanning calorimetry and viscosity measurements indicated that both the carrier and solubilized systems underwent a similar microstructure transition upon dilution. The dispersion phases gradually inverted from the water-in-oil phase (< 35% water) to the bicontinuous phase (40–45% water) and finally to the oil-in-water phase (> 45% water) along the dilution line. PMID:25996147

Solubilization of tea seed oil in a food-grade water-dilutable microemulsion.

PubMed

Deng, Lingli; Que, Fei; Wei, Hewen; Xu, Guangwei; Dong, Xiaowei; Zhang, Hui

2015-01-01

Food-grade microemulsions containing oleic acid, ethanol, Tween 20, and water were formulated as a carrier system for tea seed oil (Camellia oleifera Abel.). The effect of ethanol on the phase behavior of the microemulsion system was clearly reflected in pseudo-ternary diagrams. The solubilization capacity and solubilization efficiency of tea seed oil dispersions were measured along the dilution line at a 70/30 surfactant/oil mass ratio with Tween 20 as the surfactant and oleic acid and ethanol (1:3, w/w) as the oil phase. The dispersed phase of the microemulsion (1.5% weight ratio of tea seed oil to the total amount of oil, surfactant, and tea seed oil) could be fully diluted with water without phase separation. Differential scanning calorimetry and viscosity measurements indicated that both the carrier and solubilized systems underwent a similar microstructure transition upon dilution. The dispersion phases gradually inverted from the water-in-oil phase (< 35% water) to the bicontinuous phase (40-45% water) and finally to the oil-in-water phase (> 45% water) along the dilution line.

A phase screen model for simulating numerically the propagation of a laser beam in rain

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

Lukin, I P; Rychkov, D S; Falits, A V

2009-09-30

The method based on the generalisation of the phase screen method for a continuous random medium is proposed for simulating numerically the propagation of laser radiation in a turbulent atmosphere with precipitation. In the phase screen model for a discrete component of a heterogeneous 'air-rain droplet' medium, the amplitude screen describing the scattering of an optical field by discrete particles of the medium is replaced by an equivalent phase screen with a spectrum of the correlation function of the effective dielectric constant fluctuations that is similar to the spectrum of a discrete scattering component - water droplets in air. Themore » 'turbulent' phase screen is constructed on the basis of the Kolmogorov model, while the 'rain' screen model utiises the exponential distribution of the number of rain drops with respect to their radii as a function of the rain intensity. Theresults of the numerical simulation are compared with the known theoretical estimates for a large-scale discrete scattering medium. (propagation of laser radiation in matter)« less

Non-invasive analysis of swelling in polymer dispersions by means of time-domain(TD)-NMR.

PubMed

Nestle, Nikolaus; Häberle, Karl

2009-11-03

In this contribution, we discuss the potential of low-field time-domain(TD)-NMR to study the swelling of (aqueous) polymer dispersions by a volatile solvent. Due to the sensitivity of transverse relaxation times (T2) to swelling-induced changes in the molecular dynamics of the polymer component, the effects of swelling can be measured without spectral resolution. The measurement is performed on polymer dispersions in native state with solids contents around 50% in a non-invasive way without separating the polymeric phase and the water phase from each other. Using acetone in two polyurethane (PU) dispersions with different hard phase contents, we explore the sensitivity of the method and present a data evaluation strategy based on multicomponent fitting and proton balancing. Furthermore, we report exchange continualization as a further effect that needs to be taken into account for correct interpretation of the data.

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

PubMed

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

2016-08-24

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

Ionic liquid/water mixtures: from hostility to conciliation.

PubMed

Kohno, Yuki; Ohno, Hiroyuki

2012-07-21

Water was originally inimical to ionic liquids (ILs) especially in the analysis of their detailed properties. Various data on the properties of ILs indicate that there are two ways to design functions of ionic liquids. The first is to change the structure of component ions, to provide "task-specific ILs". The second is to mix ILs with other components, such as other ILs, organic solvents or water. Mixing makes it easy to control the properties of the solution. In this strategy, water is now a very important partner. Below, we summarise our recent results on the properties of IL/water mixtures. Stable phase separation is an effective method in some separation processes. Conversely, a dynamic phase change between a homogeneous mixture and separation of phases is important in many fields. Analysis of the relation between phase behaviour and the hydration state of the component ions indicates that the pattern of phase separation is governed by the hydrophilicity of the ions. Sufficiently hydrophilic ions yielded ILs that are miscible with water, and hydrophobic ions gave stable phase separation with water. ILs composed of hydrophobic but hydrated ions undergo a dynamic phase change between a homogeneous mixture and separate phases according to temperature. ILs having more than seven water molecules per ion pair undergo this phase transition. These dynamic phase changes are considered, with some examples, and application is made to the separation of water-soluble proteins.

Production of superheated steam from vapor-dominated geothermal reservoirs

USGS Publications Warehouse

Truesdell, A.H.; White, D.E.

1973-01-01

Vapor-dominated geothermal systems such as Larderello, Italy, The Geysers, California, and Matsukawa, Japan yield dry or superheated steam when exploited. Models for these systems are examined along with production data and the thermodynamic properties of water, steam and rock. It is concluded that these systems initially consist of a water and steam filled reservoir, a water-saturated cap rock, and a water or brine-saturated deep reservoir below a water table. Most liquid water in all parts of the system is relatively immobilized in small pores and crevices; steam dominates the large fractures and voids of the reservoir and is the continuous, pressure-controlling phase. With production, the pressure is lowered and the liquid water boils, causing massive transfer of heat from the rock and its eventual drying. Passage of steam through already dried rock produces superheating. After an initial vaporization of liquid water in the reservoir, the decrease in pressure produces increased boiling below the deep water table. With heavy exploitation, boiling extends deeper into hotter rock and the temperature of the steam increases. This model explains most features of the published production behavior of these systems and can be used to guide exploitation policies. ?? 1973.

Extent and relevance of stacking disorder in “ice Ic”

PubMed Central

Kuhs, Werner F.; Sippel, Christian; Falenty, Andrzej; Hansen, Thomas C.

2012-01-01

A solid water phase commonly known as “cubic ice” or “ice Ic” is frequently encountered in various transitions between the solid, liquid, and gaseous phases of the water substance. It may form, e.g., by water freezing or vapor deposition in the Earth’s atmosphere or in extraterrestrial environments, and plays a central role in various cryopreservation techniques; its formation is observed over a wide temperature range from about 120 K up to the melting point of ice. There was multiple and compelling evidence in the past that this phase is not truly cubic but composed of disordered cubic and hexagonal stacking sequences. The complexity of the stacking disorder, however, appears to have been largely overlooked in most of the literature. By analyzing neutron diffraction data with our stacking-disorder model, we show that correlations between next-nearest layers are clearly developed, leading to marked deviations from a simple random stacking in almost all investigated cases. We follow the evolution of the stacking disorder as a function of time and temperature at conditions relevant to atmospheric processes; a continuous transformation toward normal hexagonal ice is observed. We establish a quantitative link between the crystallite size established by diffraction and electron microscopic images of the material; the crystallite size evolves from several nanometers into the micrometer range with progressive annealing. The crystallites are isometric with markedly rough surfaces parallel to the stacking direction, which has implications for atmospheric sciences. PMID:23236184

Reducing Pumping Power in Hydronic Heating and Cooling Systems with Microencapsulated Phase Change Material Slurries

NASA Astrophysics Data System (ADS)

Karas, Kristoffer Jason

Phase change materials (PCMs) are being used increasingly in a variety of thermal transfer and thermal storage applications. This thesis presents the results of a laboratory study into the feasibility of improving the performance of hydronic heating and cooling systems by adding microcapsules filled with a PCM to the water used as heat transport media in these systems. Microencapsulated PCMs (MPCMs) increase the heat carrying capacity of heat transport liquids by absorbing or releasing heat at a constant temperature through a change of phase. Three sequences of tests and their results are presented: 1) Thermal cycling tests conducted to determine the melting temperatures and extent of supercooling associated with the MPCMs tested. 2) Hydronic performance tests in which MPCM slurries were pumped through a fin-and-tube, air-to-liquid heat exchanger and their thermal transfer performance compared against that of ordinary water. 3) Mechanical stability tests in which MPCM slurries were pumped in a continuous loop in order to gauge the extent of rupture due to pumping. It is shown that slurries consisting of water and MPCMs ˜ 14-24 mum in diameter improve thermal performance and offer the potential for power savings in the form of reduced pumping requirements. In addition, it is shown that while slurries of MPCMs 2-5 mum in diameter appear to exhibit better mechanical stability than slurries of larger diameter MPCMs, the smaller MPCMs appear to reduce the thermal performance of air-to-liquid heat exchangers.

Surface and Interface Chemistry for Gate Stacks on Silicon

NASA Astrophysics Data System (ADS)

Frank, M. M.; Chabal, Y. J.

This chapter addresses the fundamental silicon surface science associated with the continued progress of nanoelectronics along the path prescribed by Moore's law. Focus is on hydrogen passivation layers and on ultrathin oxide films encountered during silicon cleaning and gate stack formation in the fabrication of metal-oxide-semiconductor field-effect transistors (MOSFETs). Three main topics are addressed. (i) First, the current practices and understanding of silicon cleaning in aqueous solutions are reviewed, including oxidizing chemistries and cleans leading to a hydrogen passivation layer. The dependence of the final surface termination and morphology/roughness on reactant choice and pH and the influence of impurities such as dissolved oxygen or metal ions are discussed. (ii) Next, the stability of hydrogen-terminated silicon in oxidizing liquid and gas phase environments is considered. In particular, the remarkable stability of hydrogen-terminated silicon surface in pure water vapor is discussed in the context of atomic layer deposition (ALD) of high-permittivity (high-k) gate dielectrics where water is often used as an oxygen precursor. Evidence is also provided for co-operative action between oxygen and water vapor that accelerates surface oxidation in humid air. (iii) Finally, the fabrication of hafnium-, zirconium- and aluminum-based high-k gate stacks is described, focusing on the continued importance of the silicon/silicon oxide interface. This includes a review of silicon surface preparation by wet or gas phase processing and its impact on high-k nucleation during ALD growth, and the consideration of gate stack capacitance and carrier mobility. In conclusion, two issues are highlighted: the impact of oxygen vacancies on the electrical characteristics of high-k MOS devices, and the way alloyed metal ions (such as Al in Hf-based gate stacks) in contact with the interfacial silicon oxide layer can be used to control flatband and threshold voltages.

Mechanisms Related to Different Generations of gamma’ Precipitation During Continuous Cooling of a Nickel Base Superalloy

DTIC Science & Technology

2012-04-01

strongly depen- dent on the cooling rate employed. Faster cooling rates, such as those encountered during water quenching the alloy from the high temperature...precipitates. Subsequently on quenching to a lower temperature a second generation of c0 precipitates are formed that are considerably smaller in size and...annealing after rapid quenching of the alloy from the high temperature single c phase field. Therefore, typically these studies have focused on amonomodal

Biomechanical Analysis of Military Boots: Phase 2. Volume 1. Human User Testing of Military and Commercial Footwear

DTIC Science & Technology

1996-02-01

jungle boots, were subjected to tests of forefoot flexibility, rearfoot stability, outsole wear, water penetration, outsole friction, and impact...Testing of forefoot flexibility with the uppers in place revealed that the combat and the jungle boots were less flexible than all commercial items...began at the time of foot strike , or initial contact of the foot with the ground, and continued through toe-off, or termination of contact of the foot

Bear Creek Valley characterization area mixed wastes passive in situ treatment technology demonstration project - status report

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

Watson, D.; Leavitt, M.; Moss, D.

1997-03-01

Historical waste disposal activities within the Bear Creek Valley (BCV) Characterization Area (CA), at the U.S. Department of Energy (DOE) Oak Ridge Y-12 plant, have contaminated groundwater and surface water above human health risk levels and impacted the ecology of Bear Creek. Contaminates include nitrate, radioisotopes, metals, volatile organic chemicals (VOCS), and common ions. This paper provides a status report on a technology demonstration project that is investigating the feasibility of using passive in situ treatment systems to remove these contaminants. Although this technology may be applicable to many locations at the Oak Ridge Y-12 Plant, the project focuses onmore » collecting the information needed to take CERCLA removal actions in 1998 at the S-3 Disposal Ponds site. Phase 1 has been completed and included site characterization, laboratory screening of treatment media (sorbents; and iron), and limited field testing of biological treatment systems. Batch tests using different Y-12 Plant waters were conducted to evaluate the removal efficiencies of most of the media. Phase 1 results suggest that the most promising treatment media are Dowex 21 k resin, peat moss, zero-valent iron, and iron oxides. Phase 2 will include in-field column testing of these media to assess loading rates, and concerns with clogging, by-products, and long-term treatment efficiency and media stability. Continued testing of wetlands and algal mats (MATs) will be conducted to determine if they can be used for in-stream polishing of surface water. Hydraulic testing of a shallow trench and horizontal well will also be completed during Phase 2. 4 refs., 3 tabs.« less

The Numerical Technique for the Landslide Tsunami Simulations Based on Navier-Stokes Equations

NASA Astrophysics Data System (ADS)

Kozelkov, A. S.

2017-12-01

The paper presents an integral technique simulating all phases of a landslide-driven tsunami. The technique is based on the numerical solution of the system of Navier-Stokes equations for multiphase flows. The numerical algorithm uses a fully implicit approximation method, in which the equations of continuity and momentum conservation are coupled through implicit summands of pressure gradient and mass flow. The method we propose removes severe restrictions on the time step and allows simulation of tsunami propagation to arbitrarily large distances. The landslide origin is simulated as an individual phase being a Newtonian fluid with its own density and viscosity and separated from the water and air phases by an interface. The basic formulas of equation discretization and expressions for coefficients are presented, and the main steps of the computation procedure are described in the paper. To enable simulations of tsunami propagation across wide water areas, we propose a parallel algorithm of the technique implementation, which employs an algebraic multigrid method. The implementation of the multigrid method is based on the global level and cascade collection algorithms that impose no limitations on the paralleling scale and make this technique applicable to petascale systems. We demonstrate the possibility of simulating all phases of a landslide-driven tsunami, including its generation, propagation and uprush. The technique has been verified against the problems supported by experimental data. The paper describes the mechanism of incorporating bathymetric data to simulate tsunamis in real water areas of the world ocean. Results of comparison with the nonlinear dispersion theory, which has demonstrated good agreement, are presented for the case of a historical tsunami of volcanic origin on the Montserrat Island in the Caribbean Sea.

Characterization of Jamaican agro-industrial wastes. Part II, fatty acid profiling using HPLC: precolumn derivatization with phenacyl bromide.

PubMed

Bailey-Shaw, Y A; Golden, K D; Pearson, A G M; Porter, R B R

2012-09-01

This paper describes the determination of fatty acid composition of coffee, citrus and rum distillery wastes using reversed-phase high-performance liquid chromatography (RP-HPLC). Lipid extracts of the waste samples are derivatized with phenacyl bromide and their phenacyl esters are separated on a C8 reversed-phase column by using continuous gradient elution with water and acetonitrile. The presence of saturated and unsaturated fatty acids in quantifiable amounts in the examined wastes, as well as the high percentage recoveries, are clear indications that these wastes have potential value as inexpensive sources of lipids. The HPLC procedures described here could be adopted for further analysis of materials of this nature.

Determination of trace level thorium and uranium in high purity gadolinium sulfate using ICP-MS with solid-phase chromatographic extraction resins

NASA Astrophysics Data System (ADS)

Ito, S.; Takaku, Y.; Ikeda, M.; Kishimoto, Y.

2018-01-01

The Super Kamiokand-Gadolinium (SK-Gd) project is the upgrade of the Super-Kamiokande (SK) detector in order to discover Supernova Relic Neutrinos (SRNs) by loading 0.2% of Gd2(SO4)3 into a 50 kton of the SK water tank. In order to continue solar neutrino measurement with low energy threshold at ˜3.5 MeV, main radioactive contamination, U and Th in Gd2(SO4)3, should be purified before loading. We developed solid-phase extraction technique to measure low concentration of U and Th in Gd2(SO4)3 by ICP-MS. The extraction technique and current status will be presented.

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

NASA Astrophysics Data System (ADS)

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

2012-03-01

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

Fouling reduction by ozone-enhanced backwashing process in ultrafiltration of petroleum-based oil in water emulsion

NASA Astrophysics Data System (ADS)

Aryanti, Nita; Prihatiningtyas, Indah; Kusworo, Tutuk Djoko

2017-06-01

Ultrafiltration membrane has been successfully applied for oily waste water treatment. However, one significant drawback of membrane technology is fouling which is responsible for permeate flux decline as well as reducing membrane performance. One method commonly used to reduce fouling is a backwashing process. The backwashing is carried out by a push of reversed flow from permeate side to the feed side of a membrane to remove fouling on the membrane pore and release fouling release fouling layer on the external side. However, for adsorptive fouling, the backwashing process was not effective. On the other hand, Ozone demonstrated great performance for reducing organics fouling. Hence this research was focused on backwashing process with ozone for removing fouling due to ultrafiltration of petroleum based oil emulsion. Gasoline and diesel oil were selected as dispersed phase, while as continuous phase was water added with Tween 80 as a surfactant. This research found that the Ozone backwashing was effective to improve flux recovery. In ultrafiltration of gasoline emulsion, the flux recovery after Ozone backwashing was in the range of 42-74%. For ultrafiltration of diesel oil emulsion, the permeate flux recovery was about 35-84%. In addition, foulant deposition was proposed and predicting that foulant deposition for ultrafiltration of gasoline-in-water emulsion was surfactant as the top layer and the oil was underneath the surfactant. On the other hand, for ultrafiltration of diesel oil-in-water emulsion, the oil was predicted as a top layer above the surfactant foulant.

3D characterization of the critical zone within a basaltic catchment using an airborne electromagnetic survey

NASA Astrophysics Data System (ADS)

Dumont, Marc; Join, Jean-Lambert; Wendling, Valentin; Aunay, Bertrand

2017-04-01

Shield volcano islands come from the succession of constructive phases and destructive phases. In this complex geological setting, weathering and paleo-weathering profiles have a major impact on the critical zone hydrology. Nevertheless those underground structures are difficult to characterize, which leads to a leak of understanding of the water balance, infiltration, and ground water flows. Airborne transient electromagnetic method, as SkyTEM dispositive, allows to proceed regional 3D resistivity mapping with almost no topographic and vegetation limitations with an investigation depth higher than 300 m. Electromagnetics results are highly sensitive to conductive layers depending of clay content, water content and water mineralization. Skytem investigations are useful to characterize the thickness of the weathering profile and its lateral variations among large areas. In addition, it provides precise information about buried valleys and paleo-weathering of older lavas flows which control preferential groundwater flows. The French Geological Survey (BRGM) conducted a SkyTEM survey over Reunion Island (2500 km2). This survey yields on a dense 3D resistivity mapping. This continuous information is used to characterize the critical zone of the experimental watershed of Rivière des Pluies. A wide range of weathering profiles has been identified. Their variations are highly dependent of lava flow ages. Furthermore, 3D resistivity model highlights buried valleys characterized by specific weathering due to groundwater flows. Hydrogeological implication is a partitioning of groundwater flows in three different reservoirs: (i) deep basal aquifer, (ii) perched aquifers and (iii) superficial flows. The two latter behaviors have been characterized and mapped above our experimental watershed. The 3D manner of airborne electromagnetics results allows describing the continuity of weathering and alteration structures. The identification of specific groundwater flow paths provides a better understanding of the relation between the surface hydrology, the unsaturated medium and the basal aquifer. This study underlines the key role of volcanic underground structures in the critical zone flows.

Biogenic volatile organic compounds (BVOCs) emission of Scots pine under drought stress - a 13CO2 labeling study to determine de novo and pool emissions under different treatments

NASA Astrophysics Data System (ADS)

Lüpke, M.

2015-12-01

Plants emit biogenic volatile organic compounds (BVOCs) to e.g. communicate and to defend herbivores. Yet BVOCs also impact atmospheric chemistry processes, and lead to e.g. the built up of secondary organic aerosols. Abiotic stresses, such as drought, however highly influence plant physiology and subsequently BVOCs emission rates. In this study, we investigated the effect of drought stress on BVOCs emission rates of Scots pine trees, a de novo and pool emitter, under controlled climate chamber conditions within a dynamic enclosure system consisting of four plant chambers. Isotopic labeling with 13CO2 was used to detect which ratio of emissions of BVOCs derives from actual synthesis and from storage organs under different treatments. Additionally, the synthesis rate of the BVOCs synthesis can be determined. The experiment consisted of two campaigns (July 2015 and August 2015) of two control and two treated trees respectively in four controlled dynamic chambers simultaneously. Each campaign lasted for around 21 days and can be split into five phases: adaptation, control, dry-out, drought- and re-watering phase. The actual drought phase lasted around five days. During the campaigns two samples of BVOCs emissions were sampled per day and night on thermal desorption tubes and analyzed by a gas chromatograph coupled with a mass spectrometer and a flame ionization detector. Additionally, gas exchange of water and CO2, soil moisture, as well as leaf and chamber temperature was monitored continuously. 13CO2 labeling was performed simultaneously in all chambers during the phases control, drought and re-watering for five hours respectively. During the 13CO2 labeling four BVOCs emission samples per chamber were taken to identify the labeling rate on emitted BVOCs. First results show a decrease of BVOCs emissions during the drought phase and a recovery of emission after re-watering, as well as different strength of reduction of single compounds. The degree of labeling with 13CO2 differed between the emitted compounds, indicating different sources (pool / de novo) within the plant.

Destruction of humic substances by pulsed electrical discharge

NASA Astrophysics Data System (ADS)

Lobanova, G. L.; Yurmazova, T. A.; Shiyan, L. N.; Machekhina, K. I.; Davidenko, M. A.

2017-01-01

Currently, the water recourses in the territory of Tomsk region are groundwater which is limited to the high concentration of iron and manganese ions and organic substances. These impurities present in water in different forms such as soluble salts ant the colloid forms. Therefore, the present work is a part of a continuations researcher of the processes in natural waters containing humic substances at the influence of pulsed electrical discharges in a layer of iron pellets. It is shown that the main stage of water purification process of humic substances during treatment by pulsed electric discharge in the layer of iron granules is a difficult process including several stages such as formation of iron oxyhydroxide colloid particles, sorption and coagulation with humic macromolecules substances, growth of particle dispersed phase and precipitation. The reason for the formation and coagulation of the dispersed phase is a different state of charge of the colloid particles (zeta potentials of (Fe (OH)3) is +8 mV, zeta potentials of (Humic substances) is -70 mV. The most intense permanganate oxidation reduction to the maximum permissible concentration occurs at the processing time equal to 10 seconds. The contact time of active erosion products with sodium humate is established and it equals to 1 hour. The value of permanganate oxidation achieves maximum permissible concentration during this time and iron concentration in solution achieves maximum permissible concentration after filtration.

Design of Phosphonium-Type Zwitterion as an Additive to Improve Saturated Water Content of Phase-Separated Ionic Liquid from Aqueous Phase toward Reversible Extraction of Proteins

PubMed Central

Ito, Yoritsugu; Kohno, Yuki; Nakamura, Nobuhumi; Ohno, Hiroyuki

2013-01-01

We designed phosphonium-type zwitterion (ZI) to control the saturated water content of separated ionic liquid (IL) phase in the hydrophobic IL/water biphasic systems. The saturated water content of separated IL phase, 1-butyl-3-methyimidazolium bis(trifluoromethanesulfonyl)imide, was considerably improved from 0.4 wt% to 62.8 wt% by adding N,N,N-tripentyl-4-sulfonyl-1-butanephosphonium-type ZI (P555C4S). In addition, the maximum water content decreased from 62.8 wt% to 34.1 wt% by increasing KH2PO4/K2HPO4 salt content in upper aqueous phosphate buffer phase. Horse heart cytochrome c (cyt.c) was dissolved selectively in IL phase by improving the water content of IL phase, and spectroscopic analysis revealed that the dissolved cyt.c retained its higher ordered structure. Furthermore, cyt. c dissolved in IL phase was re-extracted again from IL phase to aqueous phase by increasing the concentration of inorganic salts of the buffer solution. PMID:24013379

Improved water resistance of SrAl2O4: Eu2+, Dy3+ phosphor directly achieved in a water-containing medium

NASA Astrophysics Data System (ADS)

Qi, Tonggang; Xia, Haofu; Zhang, Zhanhui; Kong, Shijin; Peng, Weikang; Zhao, Qi; Huang, Zhiliang

2017-03-01

In this paper, a heterogeneous precipitation method utilizing urea hydrolysis was adopted to coat a SiO2 layer on the surface of SrAl2O4:Eu2+, Dy3+ long persistence phosphors. To avoid phosphor hydrolysis in a water-containing coating medium, the hydrolysis and polymerization reactions of tetraethyl orthosilicate (TEOS) were concerned and carried out. The crystal phases, surface morphologies, hydrolysis stability and water resistance on afterglow properties of coated phosphors were investigated. Scanning electron microscopy, energy dispersive spectrum analysis, transmission electron microscope and Fourier transform infrared spectrum results confirmed that a continuous, uniform and compact SiO2 coating layer was successfully obtained on the phosphors surface. A theoretical coating amount of 5% or higher was found to be good for hydrolysis stability. Photoluminescence results revealed the coated phosphors showed much better water resistance on afterglow properties than the uncoated phosphor. We also discussed and proposed the hydrolysis restriction mechanism of SrAl2O4:Eu2+, Dy3+ in the water-containing coating medium.

Interaction of Vasopressin and Splenda on Glucose Metabolism and Long-term Preferences under Ad-libitum and Food-restricted Conditions.

PubMed

Murphy, H M; Wideman, C H; Cleary, A M

1999-01-01

Previous research has demonstrated that vasopressin-containing rats are capable of adapting to the stress of food restriction; whereas, vasopressin-deficient rats cannot adapt to this stressor. In the present study, the value of using a low-calorie (Splenda) or no-calorie (Equal) artificial sweetener to reverse the deleterious effects of food restriction in vasopressin-deficient rats was examined. In association with this effect, the role of vasopressin in long-term preferences for the two artificial sweeteners was studied. Vasopressin-deficient, Brattleboro (DI) rats and vasopressin-containing, Long-Evans (LE) rats underwent an habituation phase during which they had ad-libitum access to food. This was followed by an experimental phase during which the rats were divided into four groups. (1) DI rats continued with ad-libitum feeding, (2) LE rats continued with ad-libitum feeding, (3) DI rats subjected to 23 h of food restriction, and (4) LE rats subjected to 23 h of food restriction. All rats had ad-libitum access to an 8% Splenda solution, a 1% Equal solution, and water throughout both phases of the experiment. The deleterious effects of food restriction were completely reversed in DI rats, including survival, no stomach pathology, and normal plasma levels of glucose and urea nitrogen.

Technical Note: MR-visualization of interventional devices using transient field alterations and balanced steady-state free precession imaging.

PubMed

Eibofner, Frank; Martirosian, Petros; Würslin, Christian; Graf, Hansjörg; Syha, Roland; Clasen, Stephan

2015-11-01

In interventional magnetic resonance imaging, instruments can be equipped with conducting wires for visualization by current application. The potential of sequence triggered application of transient direct currents in balanced steady-state free precession (bSSFP) imaging is demonstrated. A conductor and a modified catheter were examined in water phantoms and in an ex vivo porcine liver. The current was switched by a trigger pulse in the bSSFP sequence in an interval between radiofrequency pulse and signal acquisition. Magnitude and phase images were recorded. Regions with transient field alterations were evaluated by a postprocessing algorithm. A phase mask was computed and overlaid with the magnitude image. Transient field alterations caused continuous phase shifts, which were separated by the postprocessing algorithm from phase jumps due to persistent field alterations. The overlaid images revealed the position of the conductor. The modified catheter generated visible phase offset in all orientations toward the static magnetic field and could be unambiguously localized in the ex vivo porcine liver. The application of a sequence triggered, direct current in combination with phase imaging allows conspicuous localization of interventional devices with a bSSFP sequence.

Disinfection of Spacecraft Potable Water Systems by Passivation with Ionic Silver

NASA Technical Reports Server (NTRS)

Birmele, Michele N.; McCoy, LaShelle e.; Roberts, Michael S.

2011-01-01

Microbial growth is common on wetted surfaces in spacecraft environmental control and life support systems despite the use of chemical and physical disinfection methods. Advanced control technologies are needed to limit microorganisms and increase the reliability of life support systems required for long-duration human missions. Silver ions and compounds are widely used as antimicrobial agents for medical applications and continue to be used as a residual biocide in some spacecraft water systems. The National Aeronautics and Space Administration (NASA) has identified silver fluoride for use in the potable water system on the next generation spacecraft. Due to ionic interactions between silver fluoride in solution and wetted metallic surfaces, ionic silver is rapidly depleted from solution and loses its antimicrobial efficacy over time. This report describes research to prolong the antimicrobial efficacy of ionic silver by maintaining its solubility. Three types of metal coupons (lnconel 718, Stainless Steel 316, and Titanium 6AI-4V) used in spacecraft potable water systems were exposed to either a continuous flow of water amended with 0.4 mg/L ionic silver fluoride or to a static, pre-treatment passivation in 50 mg/L ionic silver fluoride with or without a surface oxidation pre-treatment. Coupons were then challenged in a high-shear, CDC bioreactor (BioSurface Technologies) by exposure to six bacteria previously isolated from spacecraft potable water systems. Continuous exposure to 0.4 mg/L ionic silver over the course of 24 hours during the flow phase resulted in a >7-log reduction. The residual effect of a 24-hour passivation treatment in 50 mg/L of ionic silver resulted in a >3-log reduction, whereas a two-week treatment resulted in a >4-log reduction. Results indicate that 0.4 mg/L ionic silver is an effective biocide against many bacteria and that a prepassivation of metal surfaces with silver can provide additional microbial control.

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

Southworth, G.R.; Loar, J.M.; Ryon, M.G.

Ecological studies of the Bear Creek watershed, which drains the area surrounding several Oak Ridge Y-12 Plant waste disposal facilities, were initiated in May 1984 and are continuing at present. These studies consisted of an initial, detailed characterization of the benthic invertebrate and fish communities in Bear Creek, and they were followed by a presently ongoing monitoring phase that involves reduced sampling intensities. The characterization phase utilized two approaches: (1) instream sampling of benthic invertebrate and fish communities in Bear Creek to identify spatial and temporal patterns in distribution and abundance and (2) laboratory bioassays on water samples from Bearmore » Creek and selected tributaries to identify potential sources of toxicity to biota. The monitoring phase of the ecological program relates to the long-term goals of identifying and prioritizing contaminant sources and assessing the effectiveness of remedial actions. It continues activities of the characterization phase at less frequent intervals. The Bear Greek Valley is a watershed that drains the area surrounding several closed Oak Ridge Y-12 Plant waste disposal facilities. Past waste disposal practices in Bear Creek Valley resulted in contamination of Bear Creek and consequent ecological damage. Extensive remedial actions have been proposed at waste sites, and some of the have been implemented or are now underway. The proposed study plan consists of an initial, detailed characterization of the benthic invertebrate and fish communities in Bear Creek in the first year followed by a reduction in sampling intensity during the monitoring phase of the plan. The results of sampling conducted from May 1984 through early 1989 are presented in this report.« less

Water Resources Data, Florida, Water Year 2003, Volume 1A: Northeast Florida Surface Water

USGS Publications Warehouse

,

2004-01-01

Water resources data for the 2003 water year in Florida consist of continuous or daily discharge for 385 streams, periodic discharge for 13 streams, continuous or daily stage for 255 streams, periodic stage for 13 streams, peak stage and discharge for 36 streams; continuous or daily elevations for 13 lakes, periodic elevations for 46 lakes; continuous ground-water levels for 441 wells, periodic ground-water levels for 1,227 wells; quality-of-water data for 133 surface-water sites and 308 wells. The data for northeast Florida include continuous or daily discharge for 138 streams, periodic discharge for 3 streams, continuous or daily stage for 61 streams, periodic stage for 0 streams; peak stage and discharge for 0 streams; continuous or daily elevations for 9 lakes, periodic elevations for 20 lakes; continuous ground water levels for 73 wells, periodic groundwater levels for 543 wells; quality-of-water data for 43 surface-water sites and 115 wells. These data represent the National Water Data System records collected by the U.S. Geological Survey and cooperating local, State and Federal agencies in Florida.

Water Resources Data, Florida, Water Year 2003, Volume 1B: Northeast Florida Ground Water

USGS Publications Warehouse

George, H.G.; Nazarian, A.P.; Dickerson, S.M.

2004-01-01

Water resources data for the 2003 water year in Florida consist of continuous or daily discharge for 385 streams, periodic discharge for 13 streams, continuous or daily stage for 255 streams, periodic stage for 13 streams, peak stage and discharge for 36 streams; continuous or daily elevations for 13 lakes, periodic elevations for 46 lakes; continuous ground-water levels for 441 wells, periodic ground-water levels for 1,227 wells; quality-of-water data for 133 surface-water sites and 308 wells. The data for northeast Florida include continuous or daily discharge for 138 streams, periodic discharge for 3 streams, continuous or daily stage for 61 streams, periodic stage for 0 streams; peak stage and discharge for 0 streams; continuous or daily elevations for 9 lakes, periodic elevations for 20 lakes; continuous ground water levels for 73 wells, periodic groundwater levels for 543 wells; quality-of-water data for 43 surface-water sites and 115 wells. These data represent the National Water Data System records collected by the U.S. Geological Survey and cooperating local, State and Federal agencies in Florida.

Effects of varying water adsorption on a Cu3(BTC)2 metal-organic framework (MOF) as studied by 1H and 13C solid-state NMR spectroscopy.

PubMed

Gul-E-Noor, Farhana; Jee, Bettina; Pöppl, Andreas; Hartmann, Martin; Himsl, Dieter; Bertmer, Marko

2011-05-07

The process of water adsorption on a dehydrated Cu(3)(BTC)(2) (copper (II) benzene 1,3,5-tricarboxylate) metal-organic framework (MOF) was studied with (1)H and (13)C solid-state NMR. Different relative amounts of water (0.5, 0.75, 1, 1.5, 2, and 5 mole equivalents with respect to copper) were adsorbed via the gas phase. (1)H and (13)C MAS NMR spectra of dehydrated and water-loaded Cu(3)(BTC)(2) samples gave evidence on the structural changes due to water adsorption within the MOF material as well as information on water dynamics. The analysis of (1)H spinning sideband intensities reveals differences in the (1)H-(63/65)Cu hyperfine coupling between dehydrated and water-loaded samples. The investigation was continued for 60 days to follow the stability of the Cu(3)(BTC)(2) network under humid conditions. NMR data reveal that Cu(3)(BTC)(2) decomposes quite fast with the decomposition being different for different water contents. This journal is © the Owner Societies 2011

Mars surface based factory. Phase 2, task 1C: Computer control of a water treatment system to support a space colony on Mars

NASA Technical Reports Server (NTRS)

Fuller, John; Ali, Warsame; Willis, Danette

1989-01-01

In a continued effort to design a surface based factory on Mars for the production of oxygen and water, a preliminary study was made of the surface and atmospheric composition on Mars and determined the mass densities of the various gases in the Martian atmosphere. Based on the initial studies, oxygen and water were determined to be the two products that could be produced economically under the Martian conditions. Studies were also made on present production techniques to obtain water and oxygen. Analyses were made to evaluate the current methods of production that were adaptable to the Martian conditions. Even though the initial effort was the production of oxygen and water, it was found necessary to produce some diluted gases that can be mixed with the oxygen produced to constitute 'breathable' air. The conceptual design of a breathable air manufacturing system, a means of drilling for underground water, and storage of water for future use were completed. The design objective was the conceptual design of an integrated system for the supply of quality water for biological consumption, farming, residential and industrial use.

Geologic controls on the formation of lakes in north-central Florida

USGS Publications Warehouse

Kindinger, Jack G.; Davis, Jeffrey B.; Flocks, James G.; Pitman, Janet K.; Carroll, Alan R.

1998-01-01

Fluid exchange between surficial waters and groundwater, as well as the processes that control this exchange, are of critical concern to water management districts and planners. Digital high-resolution seismic systems were used to collect geophysical data from 30 lakes of north-central Florida. Although using seismic profile data in the past has been less than successful, the use of digital technology has increased the potential for success. Seismic profiles collected from the lakes of north-central Florida have shown the potential application of these techniques in understanding the formation of individual lakes. In each case study, lake structure and geomorphology were controlled by solution and/or mechanical processes. Processes that control lake development are twofold: 1) karstification or dissolution of the underlying limestone, and 2) me collapse, subsidence, or slumping of overburden to form sinkholes. Initial lake formation is directly related to the karst topography of the underlying host limestone. Lake size and shape are a factor of the thickness of overburden and size of the collapse or subsidence and/or clustering of depressions allowing for lake development. Lake development is through progressive sequence stages to maturity that can be delineated into geomorphic types. Case studies have shown that lakes can be divided by geomorphic types into progressive developmental phases: (1) active subsidence or collapse phase (young) - the open to partially filled collapse structures typically associated with sink holes; (2) transitional phase (middle age) - the sinkhole is plugged as the voids within the collapse are filled with sediment, periodic reactivation may occur; (3) baselevel phase (mature) - active sinkholes are progressively plugged by the continual erosion of material into the basin, and eventually sediment fills the basins; and (4) polje (drowned prairie) - broad flat-bottom basins located within the epiphreatic zone that are inundated at high stages of the water table and have one or all phases of sinkhole development and many types of karst and karren features. Most lakes in this study have a small diameter (

Results of the second phase of the drought-disaster test-drilling program near Morristown, N.J.

USGS Publications Warehouse

Vecchioli, John; Nichols, William D.; Nemickas, Bronius

1967-01-01

The continued drought in northeastern New Jersey through the summer of 1966 with its attendant water-supply problems resulted in an extension of the drought-disaster test-drilling program originally requested by the Office of Emergency Planning on August 30, 1965. Authorization to continue test drilling was fiven by the Office of Emergency Planning on September 26, 1966, with the stipulation that all field work be complete by January 31, 1977. Contractural costs were paid by the Office of Emergency Planning, whereas personnel costs were shared by the U.S. Geological Survey and the New Jersey Department of Conservation and Economic Development, Division of Water Policy and Supply.The work undertaken in 1965 by the Geological Survey was "...to preform the necessary drilling and testing of wells to identify the extent and nature of a reserve ground-water source in the vicinity of the Passaic River near the northern New Jersey metropolitan area." Results of this first phase were made available in the fall of 1966 in Water Resources Circular 16 of the New Jersey Department of Conservation and Economic Development. Three of the five areas tested (figure 1)--two in Parsippany-Troy Hills Township (areas 2 and 4) and one in East Hanover Township (area 1), Morris County--proved capable of providing an aggregate sustained yield of 7.5 million gallons daily (mgd) from wells constructed in sand and gravel deposits. Because significant supplies of ground water for emergency use were located in the first phase of the exploratory test-drilling program, it was though desirable to extend the originally planned studies so as to obtain maximum practicable information on emergency supplies.During this second phase of the investigation, drilling was conducted in 16 sites in Chatham, Madison, and Florham Park Boroughs and in Hanover and East Hanover Townships, Morris County. (See figure 2.) The drilling in Hanover and East Hanover Townships, and part of the drilling done in Florham Park was to explore the availability of large undeveloped ground-water supplies. Drilling in Chatham, Madison, and Florham Park Boroughs was done primarily to determine the extent and continuity of buried valley-fill aquifers, so that a full evaluation of the effects of pumpage from other areas on these already heavily pumped areas could be made. In addition, it was anticipated that the drilling could help in defining the feasibility of artificial recharge of the heavily pumped areas and in the determination of the prospective method of recharge and points of emplacement.Arrangements for easements with landowners, preparation of specifications for well drilling and seismic work, and supervision of well drilling and seismic contracts were all performed by the New Jersey District, Water Resources Division of the Geological Survey.Prior to the test drilling, seismic exploration under contract with Alpine Geophysical Associates of Norwood, N. J. was conducted at five locations in the Chatham-Madison-Florham Park area and at one place in Parsippany-Troy Hills Township. The seismic work was done to determine the most favorable location for a test well at several potential test-well sites and to help in the interpretation of subsurface geology between test sites.Contracts for the drilling of the test holes were awarded during November and drilling commences on November 30. Kaye Well drilling, Inc. of Jackson, N. J. was the recipient of a contract for eight of the test holes, and a second contract was awarded to Rinbrand Well Drilling Co., Inc. of Glen Rock, N. J.--also for eight test holes.Acknowledgment is due to the many public officials of Chatham, Madison, Florham Park, Morristown, and East Hanover Township as well as officials of the Braidburn Corporation and Esso Research and Engineering Co., who cooperated by making their lands available for exploration.

Shallow bedrock limits groundwater seepage-based headwater climate refugia

USGS Publications Warehouse

Briggs, Martin A.; Lane, John W.; Snyder, Craig D.; White, Eric A.; Johnson, Zachary; Nelms, David L.; Hitt, Nathaniel P.

2018-01-01

Groundwater/surface-water exchanges in streams are inexorably linked to adjacent aquifer dynamics. As surface-water temperatures continue to increase with climate warming, refugia created by groundwater connectivity is expected to enable cold water fish species to survive. The shallow alluvial aquifers that source groundwater seepage to headwater streams, however, may also be sensitive to seasonal and long-term air temperature dynamics. Depth to bedrock can directly influence shallow aquifer flow and thermal sensitivity, but is typically ill-defined along the stream corridor in steep mountain catchments. We employ rapid, cost-effective passive seismic measurements to evaluate the variable thickness of the shallow colluvial and alluvial aquifer sediments along a headwater stream supporting cold water-dependent brook trout (Salvelinus fontinalis) in Shenandoah National Park, VA, USA. Using a mean depth to bedrock of 2.6 m, numerical models predicted strong sensitivity of shallow aquifer temperature to the downward propagation of surface heat. The annual temperature dynamics (annual signal amplitude attenuation and phase shift) of potential seepage sourced from the shallow modeled aquifer were compared to several years of paired observed stream and air temperature records. Annual stream water temperature patterns were found to lag local air temperature by ∼8–19 d along the stream corridor, indicating that thermal exchange between the stream and shallow groundwater is spatially variable. Locations with greater annual signal phase lag were also associated with locally increased amplitude attenuation, further suggestion of year-round buffering of channel water temperature by groundwater seepage. Numerical models of shallow groundwater temperature that incorporate regional expected climate warming trends indicate that the summer cooling capacity of this groundwater seepage will be reduced over time, and lower-elevation stream sections may no longer serve as larger-scale climate refugia for cold water fish species, even with strong groundwater discharge.

Modelling of Dispersed Gas-Liquid Flow using LBGK and LPT Approach

NASA Astrophysics Data System (ADS)

Agarwal, Alankar; Prakash, Akshay; Ravindra, B.

2017-11-01

The dynamics of gas bubbles play a significant, if not crucial, role in a large variety of industrial process that involves using reactors. Many of these processes are still not well understood in terms of optimal scale-up strategies.An accurate modeling of bubbles and bubble swarms become important for high fidelity bioreactor simulations. This study is a part of the development of robust bubble fluid interaction modules for simulation of industrial-scale reactors. The work presents the simulation of a single bubble rising in a quiescent water tank using current models presented in the literature for bubble-fluid interaction. In this multiphase benchmark problem, the continuous phase (water) is discretized using the Lattice Bhatnagar-Gross and Krook (LBGK) model of Lattice Boltzmann Method (LBM), while the dispersed gas phase (i.e. air-bubble) modeled with the Lagrangian particle tracking (LPT) approach. The cheap clipped fourth order polynomial function is used to model the interaction between two phases. The model is validated by comparing the simulation results for terminal velocity of a bubble at varying bubble diameter and the influence of bubble motion in liquid velocity with the theoretical and previously available experimental data. This work is supported by the ``Centre for Development of Advanced Computing (C-DAC), Pune'' by providing the advanced computational facility in PARAM Yuva-II.

Monitoring reactive microencapsulation dynamics using microfluidics

PubMed Central

Brosseau, Quentin; Baret, Jean-Christophe

2015-01-01

We use microfluidic polydimethylsiloxane (PDMS) devices to measure the kinetics of reactive encapsulations occurring at the interface of emulsion droplets. The formation of the polymeric shell is inferred from the droplet deformability measured in a series of expansion–constriction chambers along the microfluidic chip. With this tool we quantify the kinetic processes governing the encapsulation at the very early stage of shell formation with a time resolution of the order of the millisecond for overall reactions occurring in less than 0.5 s. We perform a comparison of monomer reactivities used for the encapsulation. We study the formation of polyurea microcapsules (PUMCs); the shell formation proceeds at the water–oil interface by an immediate reaction of amines dissolved in the aqueous phase and isocyanates dissolved in the oil phase. We observe that both monomers contribute differently to the encapsulation kinetics. The kinetics of the shell formation process at the oil-in-water (O/W) experiments significantly differs from the water-in-oil (W/O) systems; the component dissolved in the continuous phase has the largest impact on the kinetics. In addition, we quantified the retarding effect on the encapsulation kinetics by the interface stabilizing agent (surfactant). Our approach is valuable for quantifying in situ reactive encapsulation processes and provides guidelines to generate microcapsules with soft interfaces of tailored and controllable interfacial properties. PMID:25705975

High-efficiency tri-band quasi-continuous phase gradient metamaterials based on spoof surface plasmon polaritons

PubMed Central

Li, Yongfeng; Ma, Hua; Wang, Jiafu; Pang, Yongqiang; Zheng, Qiqi; Chen, Hongya; Han, Yajuan; Zhang, Jieqiu; Qu, Shaobo

2017-01-01

A high-efficiency tri-band quasi-continuous phase gradient metamaterial is designed and demonstrated based on spoof surface plasmon polaritons (SSPPs). High-efficiency polarizaiton conversion transmission is firstly achieved via tailoring phase differece between the transmisive SSPP and the space wave in orthogonal directions. As an example, a tri-band circular-to-circular (CTC) polarization conversion metamateiral (PCM) was designed by a nonlinearly dispersive phase difference. Using such PCM unit cell, a tri-band quasi-continuous phase gradient metamaterial (PGM) was then realized by virtue of the Pancharatnam-Berry phase. The distribution of the cross-polarization transmission phase along the x-direction is continuous except for two infinitely small intervals near the phases 0° and 360°, and thus the phase gradient has definition at any point along the x-direction. The simulated normalized polarization conversion transmission spectrums together with the electric field distributions for circularly polarized wave and linearly polarized wave demonstrated the high-efficiency anomalous refraction of the quasi-continuous PGM. The experimental verification for the linearly polarized incidence was also provided. PMID:28079185

Vapor Phase Catalytic Ammonia Reduction

NASA Technical Reports Server (NTRS)

Flynn, Michael T.; Harper, Lynn D. (Technical Monitor)

1994-01-01

This paper discusses the development of a Vapor Phase Catalytic Ammonia Reduction (VPCAR) teststand and the results of an experimental program designed to evaluate the potential of the technology as a water purification process. In the experimental program the technology is evaluated based upon product water purity, water recovery rate, and power consumption. The experimental work demonstrates that the technology produces high purity product water and attains high water recovery rates at a relatively high specific power consumption. The experimental program was conducted in 3 phases. In phase I an Igepon(TM) soap and water mixture was used to evaluate the performance of an innovative Wiped-Film Rotating-Disk evaporator and associated demister. In phase II a phenol-water solution was used to evaluate the performance of the high temperature catalytic oxidation reactor. In phase III a urine analog was used to evaluate the performance of the combined distillation/oxidation functions of the processor.

In-situ continuous water analyzing module

DOEpatents

Thompson, Cyril V.; Wise, Marcus B.

1998-01-01

An in-situ continuous liquid analyzing system for continuously analyzing volatile components contained in a water source comprises: a carrier gas supply, an extraction container and a mass spectrometer. The carrier gas supply continuously supplies the carrier gas to the extraction container and is mixed with a water sample that is continuously drawn into the extraction container. The carrier gas continuously extracts the volatile components out of the water sample. The water sample is returned to the water source after the volatile components are extracted from it. The extracted volatile components and the carrier gas are delivered continuously to the mass spectometer and the volatile components are continuously analyzed by the mass spectrometer.

40 CFR 86.1915 - What are the requirements for Phase 1 and Phase 2 testing?

Code of Federal Regulations, 2011 CFR

2011-07-01

... (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED) Manufacturer-Run In-Use Testing Program for Heavy-Duty Diesel Engines § 86.1915 What are the requirements for Phase 1 and Phase 2 testing? For all selected engine families, you must do the following: (a...

40 CFR 86.1915 - What are the requirements for Phase 1 and Phase 2 testing?

Code of Federal Regulations, 2013 CFR

2013-07-01

... (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED) Manufacturer-Run In-Use Testing Program for Heavy-Duty Diesel Engines § 86.1915 What are the requirements for Phase 1 and Phase 2 testing? For all selected engine families, you must do the following: (a...

40 CFR 86.1915 - What are the requirements for Phase 1 and Phase 2 testing?

Code of Federal Regulations, 2012 CFR

2012-07-01

... (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED) Manufacturer-Run In-Use Testing Program for Heavy-Duty Diesel Engines § 86.1915 What are the requirements for Phase 1 and Phase 2 testing? For all selected engine families, you must do the following: (a...

40 CFR 86.1915 - What are the requirements for Phase 1 and Phase 2 testing?

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED) Manufacturer-Run In-Use Testing Program for Heavy-Duty Diesel Engines § 86.1915 What are the requirements for Phase 1 and Phase 2 testing? For all selected engine families, you must do the following: (a...

Conversion of a wet waste feedstock to biocrude by hydrothermal processing in a continuous-flow reactor: grape pomace

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

Elliott, Douglas C.; Schmidt, Andrew J.; Hart, Todd R.

Wet waste feedstocks present an apt opportunity for biomass conversion to fuels by hydrothermal processing. In this study, grape pomace slurries from two varieties, Montepulciano and cabernet sauvignon, have been converted into a biocrude by hydrothermal liquefaction (HTL) in a bench-scale, continuous-flow reactor system. Carbon conversion to gravity-separable biocrude product up to 56 % was accomplished at relatively low temperature (350 C) in a pressurized (sub-critical liquid water) environment (20 MPa) when using grape pomace feedstock slurry with a 16.8 wt% concentration of dry solids processed at a liquid hourly space velocity of 2.1 h-1. Direct oil recovery was achievedmore » without the use of a solvent and biomass trace mineral components were removed by processing steps so that they did not cause processing difficulties. In addition, catalytic hydrothermal gasification (CHG) was effectively applied for HTL byproduct water cleanup using a Ru on C catalyst in a fixed bed producing a gas composed of methane and carbon dioxide from water soluble organics. Conversion of 99.8% of the chemical oxygen demand (COD) left in the aqueous phase was demonstrated. As a result, high conversion of grape pomace to liquid and gas fuel products was found with residual organic contamination in byproduct water reduced to <150 mg/kg COD.« less

Revisiting a Hydrological Analysis Framework with International Satellite Land Surface Climatology Project Initiative 2 Rainfall, Net Radiation, and Runoff Fields

NASA Technical Reports Server (NTRS)

Koster, Randal D.; Fekete, Balazs M.; Huffman, George J.; Stackhouse, Paul W.

2006-01-01

The International Satellite Land Surface Climatology Project Initiative 2 (ISLSCP-2) data set provides the data needed to characterize the surface water budget across much of the globe in terms of energy availability (net radiation) and water availability (precipitation) controls. The data, on average, are shown to be consistent with Budyko s decades-old framework, thereby demonstrating the continuing relevance of Budyko s semiempirical relationships. This consistency, however, appears only when a small subset of the data with hydrologically suspicious behavior is removed from the analysis. In general, the precipitation, net radiation, and runoff data also appear consistent in their interannual variability and in the phasing of their seasonal cycles.

Changes to the hydrography and zooplankton in the northern California Current in response to `the Blob'of 2014-2015

NASA Astrophysics Data System (ADS)

Peterson, W. T.

2016-02-01

Fortnightly measurements of hydrography and zooplankton species composition have been sustained along the Newport Hydrographic line since 1996. From this 20 year time series we have established that zooplankton abundance and species composition closely tracks the phase of the Pacific Decadal Oscillation and the El Nino Southern Oscillation. During positive (warm) phase of the PDO, a warm water `southern' subtropical coastal community is found whereas during negative (cold) phase a cold water `northern'coastal community dominates. The Blob though was a rule-changer. The Blob began to move slowly ashore at Newport on 14 September 2014 with the seasonal relaxation of upwelling, and within 5 h SST increased 6°C to 19.4°C. On the 25 and 30 September cruises, copepod species richness increased as well, with an anomaly of 2 and 9 species respectively, greater than the 20 year climatology for September. We continued to monitor the plankton throughout the autumn 2014 and winter, spring and summer 2015 and found a total of seventeen copepod species that were either new to Oregon or have occurred only rarely in the past. Many of these species are oceanic with sub-tropical or tropical affinities thus are indicators of tropical waters, suggesting that the Blob water which came ashore in central Oregon had its origins offshore rather than from coastal waters to the south. Some of the copepod species that were new or rarely seen included Subeucalanus crassus, Eucalanus hyalinus, Mecynocera clausi, Calocalanus pavo, Centropages bradyii, and Pleuromamma borealis and P. xiphias. Krill biomass was the lowest in our 20 year time series. The southern California Current neritic krill species Nyctiphanes simplex appears off Oregon during major El Niño events (1983, 1998), but none were seen during The Blob event which again suggests that the origin of the Blob water which appeared off Oregon was from far offshore, not from coastal waters to the south. Note in the figure below that species richness during the Blob period was greater than that observed during the 1997-98 El Nino and lesser El Nino events in 2003-2005 and 2009-10.

Why Do Some Estuaries Close: A Model of Estuary Entrance Morphodynamics.

NASA Astrophysics Data System (ADS)

McSweeney, S. L.; Kennedy, D. M.; Rutherfurd, I.

2014-12-01

Intermittently Closed/Open Coastal Lakes/Lagoons (ICOLLs) are a form of wave-dominated, microtidal estuary that experience periodic closure in times of low river flow. ICOLL entrance morphodynamics are complex due to the interaction between wave, tidal and fluvial processes. Managers invest substantial funds to artificially open ICOLLs as they flood surrounding property and infrastructure, and have poor water quality. Existing studies examine broad scale processes but do not identify the main drivers of entrance condition. In this research, the changes in entrance geomorphology were surveyed before and after artificial entrance openings in three ICOLLs in Victoria, Australia. Changes in morphology were related to continuous measures of sediment volume, water level, tide and wave energy. A six-stage quantitative phase model of entrance geomorphology and hydrodynamics is presented to illustrate the spatio-temporal variability in ICOLL entrance morphodynamics. Phases include: breakout; channel expansion with rapid outflow; open with tidal exchange; initial berm rebuilding with tidal attenuation; partial berm recovery with rising water levels; closed with perched water levels. Entrance breakout initiates incision of a pilot channel to the ocean, whereby basin water levels then decline and channel expansion as the headcut migrates landwards. Peak outflow velocities of 5 m/s-3 were recorded and channel dimensions increased over 6 hrs to 3.5 m deep and 140 m wide. When tidal, a clear semi-diurnal signal is superimposed upon an otherwise stable water level. Deep-water wave energy was transferred 1.8 km upstream of the rivermouth with bores present in the basin. Berm rebuilding occurred by littoral drift and cross-shore transport once outflow ceased and microscale bedform features, particularly antidunes, contributed to sediment progradation. Phase duration is dependant on how high the estuary was perched above mean sea level, tidal prism extent, and onshore sediment supply. High offshore wave height and frequency, in addition to littoral drift magnitude, were main drivers of closure. This study presents a predictive model of entrance morphodynamics whereby managers can determine proximity to natural closure or opening, and as a result identify whether implementing an artificial opening is worthwhile.

Covalent attachment of microbial lipase onto microporous styrene-divinylbenzene copolymer by means of polyglutaraldehyde.

PubMed

Dizge, Nadir; Keskinler, Bülent; Tanriseven, Aziz

2008-10-01

A novel method for immobilization of Thermomyces lanuginosus lipase onto polyglutaraldehyde-activated poly(styrene-divinylbenzene) (STY-DVB), which is a hydrophobic microporous support has been successfully developed. The copolymer was prepared by the polymerization of the continuous phase of a high internal phase emulsion (polyHIPE). The concentrated emulsion consists of a mixture of styrene and divinylbenzene containing a suitable surfactant and an initiator as the continuous phase and water as the dispersed phase. Lipase from T. lanuginosus was immobilized covalently with 85% yield on the internal surface of the hydrophobic microporous poly(styrene-divinylbenzene) copolymer and used as a biocatalyst for the transesterification reaction. The immobilized enzyme has been fully active 30 days in storage and retained the activity during the 15 repeated batch reactions. The properties of free and immobilized lipase were studied. The effects of protein concentration, pH, temperature, and time on the immobilization, activity, and stability of the immobilized lipase were also studied. The newly synthesized microporous poly(styrene-divinylbenzene) copolymer constitutes excellent support for lipase. It given rise to high immobilization yield, retains enzymatic activity for 30 days, stable in structure and allows for the immobilization of large amount of protein (11.4mg/g support). Since immobilization is simple yet effective, the newly immobilized lipase could be used in several application including oil hydrolysis, production of modified oils, biodiesel synthesis, and removal of fatty acids from oils.

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

USGS Publications Warehouse

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

2004-01-01

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

TES buffer-induced phase separation of aqueous solutions of several water-miscible organic solvents at 298.15 K: phase diagrams and molecular dynamic simulations.

PubMed

Taha, Mohamed; Lee, Ming-Jer

2013-06-28

Water and the organic solvents tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, 1-propanol, 2-propanol, tert-butanol, acetonitrile, or acetone are completely miscible in all proportions at room temperature. Here, we present new buffering-out phase separation systems that the above mentioned organic aqueous solutions can be induced to form two liquid phases in the presence of a biological buffer 2-[[1,3-dihydroxy-2-(hydroxymethyl)propan-2-yl]amino]ethanesulfonic acid (TES). The lower liquid phase is rich in water and buffer, and the upper phase is organic rich. This observation has both practical and mechanistic interests. The phase diagrams of these systems were constructed by experimental measurements at ambient conditions. Molecular dynamic (MD) simulations were performed for TES + water + THF system to understand the interactions between TES, water, and organic solvent at molecular level. Several composition-sets for this system, beyond and inside the liquid-liquid phase-splitting region, have been simulated. Interestingly, the MD simulation for compositions inside the phase separation region showed that THF molecules are forced out from the water network to start forming a new liquid phase. The hydrogen-bonds, hydrogen-bonds lifetimes, hydrogen-bond energies, radial distribution functions, coordination numbers, the electrostatic interactions, and the van der Waals interactions between the different pairs have been calculated. Additionally, MD simulations for TES + water + tert-butanol∕acetonitrile∕acetone phase separation systems were simulated. The results from MD simulations provide an explanation for the buffering-out phenomena observed in [TES + water + organic solvent] systems by a mechanism controlled by the competitive interactions of the buffer and the organic solvent with water. The molecular mechanism reported here is helpful for designing new benign separation materials.

Evolution of volume fractions and droplet sizes by analysis of electrical conductance curves during destabilization of oil-in-water emulsions.

PubMed

Kostoglou, M; Varka, E-M; Kalogianni, E P; Karapantsios, T D

2010-09-01

Destabilization of hexane-in-water emulsions is studied by a continuous, non-intrusive, multi-probe, electrical conductance technique. Emulsions made of different oil fractions and surfactant (C(10)E(5)) concentrations are prepared in a stirred vessel using a Rushton turbine to break and agitate droplets. During the separation of phases, electrical signals from pairs of ring electrodes mounted at different heights onto the vessel wall, are recorded. The evolution of the local water volume fractions at the locations of the electrodes is estimated from these signals. It is found that in the absence of coalescence, the water fraction evolution curve from the bottom pair of electrodes is compatible with a bidisperse oil droplet size distribution. The sizes and volume fractions of the two droplet modes are estimated using theoretical arguments. The electrically determined droplet sizes are compared to data from microscopy image analysis. Results are discussed in detail. Copyright 2010 Elsevier Inc. All rights reserved.

Low-Energy Water Recovery from Subsurface Brines

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

Choi, Young Chul; Kim, Gyu Dong; Hendren, Zachary

A novel non-aqueous phase solvent (NAS) desalination process was proposed and developed in this research project. The NAS desalination process uses less energy than thermal processes, doesn’t require any additional chemicals for precipitation, and can be utilized to treat high TDS brine. In this project, our experimental work determined that water solubility changes and selective absorption are the key characteristics of NAS technology for successful desalination. Three NAS desalination mechanisms were investigated: (1) CO2 switchable, (2) high-temp absorption to low-temp desorption (thermally switchable), and (3) low-temp absorption to high-temp desorption (thermally switchable). Among these mechanisms, thermally switchable (low-temp absorption tomore » high-temp desorption) showed the highest water recovery and relatively high salt rejection. A test procedure for semi-continuous, bench scale NAS desalination process was also developed and used to assess performance under a range of conditions.« less

Response of the North Atlantic surface and intermediate ocean structure to climate warming of MIS 11.

PubMed

Kandiano, Evgenia S; van der Meer, Marcel T J; Schouten, Stefan; Fahl, Kirsten; Sinninghe Damsté, Jaap S; Bauch, Henning A

2017-04-10

Investigating past interglacial climates not only help to understand how the climate system operates in general, it also forms a vital basis for climate predictions. We reconstructed vertical stratification changes in temperature and salinity in the North Atlantic for a period some 400 ka ago (MIS11), an interglacial time analogue of a future climate. As inferred from a unique set of biogeochemical, geochemical, and faunal data, the internal upper ocean stratification across MIS 11 shows distinct depth-dependent dynamical changes related to vertical as well as lateral shifts in the upper Atlantic meridional circulation system. Importantly, transient cold events are recognized near the end of the long phase of postglacial warming at surface, subsurface, mid, and deeper water layers. These data demonstrate that MIS 11 coolings over the North Atlantic were initially triggered by freshwater input at the surface and expansion of cold polar waters into the Subpolar Gyre. The cooling signal was then transmitted downwards into mid-water depths. Since the cold events occurred after the main deglacial phase we suggest that their cause might be related to continuous melting of the Greenland ice sheet, a mechanism that might also be relevant for the present and upcoming climate.

Comparison of several solid-phase extraction sorbents for continuous determination of amines in water by gas chromatography-mass spectrometry.

PubMed

Jurado-Sánchez, Beatriz; Ballesteros, Evaristo; Gallego, Mercedes

2009-08-15

A semiautomatic method has been proposed for the determination of different types of amines in water samples including anilines, chloroanilines, N-nitrosamines and aliphatic amines. The analytes were retained on a solid-phase extraction sorbent column and after elution, 1 microL of the extract was analysed by gas chromatography coupled with electron impact ionization mass spectrometry. A systematic overview is given of the advantages and disadvantages of several sorbents (LiChrolut EN, Oasis HLB, RP-C(18), graphitized carbon black, fullerenes and nanotubes) in the retention of amine compounds and based on sensitivity, selectivity and reliability. The retention efficiency for the studied amines was higher (ca. 100%) with LiChrolut EN and Oasis HLB than it was with RP-C(18) and fullerenes (53 and 62%, respectively, on average). Detection limits of 0.5-16 ng L(-1) for the 27 amines studied were obtained when using a sorbent column containing 75 mg of LiChrolut EN for 100mL of sample, the RSD being lower than 6.5%. The method was applied with good accuracy and precision in the determination of amines in various types of water including river, pond, tap, well, drinking, swimming pool and waste.

Hydrogen from catalytic reforming of biomass-derived hydrocarbons in liquid water

NASA Astrophysics Data System (ADS)

Cortright, R. D.; Davda, R. R.; Dumesic, J. A.

2002-08-01

Concerns about the depletion of fossil fuel reserves and the pollution caused by continuously increasing energy demands make hydrogen an attractive alternative energy source. Hydrogen is currently derived from nonrenewable natural gas and petroleum, but could in principle be generated from renewable resources such as biomass or water. However, efficient hydrogen production from water remains difficult and technologies for generating hydrogen from biomass, such as enzymatic decomposition of sugars, steam-reforming of bio-oils and gasification, suffer from low hydrogen production rates and/or complex processing requirements. Here we demonstrate that hydrogen can be produced from sugars and alcohols at temperatures near 500K in a single-reactor aqueous-phase reforming process using a platinum-based catalyst. We are able to convert glucose-which makes up the major energy reserves in plants and animals-to hydrogen and gaseous alkanes, with hydrogen constituting 50% of the products. We find that the selectivity for hydrogen production increases when we use molecules that are more reduced than sugars, with ethylene glycol and methanol being almost completely converted into hydrogen and carbon dioxide. These findings suggest that catalytic aqueous-phase reforming might prove useful for the generation of hydrogen-rich fuel gas from carbohydrates extracted from renewable biomass and biomass waste streams.

Hydrogen from catalytic reforming of biomass-derived hydrocarbons in liquid water.

PubMed

Cortright, R D; Davda, R R; Dumesic, J A

2002-08-29

Concerns about the depletion of fossil fuel reserves and the pollution caused by continuously increasing energy demands make hydrogen an attractive alternative energy source. Hydrogen is currently derived from nonrenewable natural gas and petroleum, but could in principle be generated from renewable resources such as biomass or water. However, efficient hydrogen production from water remains difficult and technologies for generating hydrogen from biomass, such as enzymatic decomposition of sugars, steam-reforming of bio-oils and gasification, suffer from low hydrogen production rates and/or complex processing requirements. Here we demonstrate that hydrogen can be produced from sugars and alcohols at temperatures near 500 K in a single-reactor aqueous-phase reforming process using a platinum-based catalyst. We are able to convert glucose -- which makes up the major energy reserves in plants and animals -- to hydrogen and gaseous alkanes, with hydrogen constituting 50% of the products. We find that the selectivity for hydrogen production increases when we use molecules that are more reduced than sugars, with ethylene glycol and methanol being almost completely converted into hydrogen and carbon dioxide. These findings suggest that catalytic aqueous-phase reforming might prove useful for the generation of hydrogen-rich fuel gas from carbohydrates extracted from renewable biomass and biomass waste streams.

Microfluidic-SANS: insitu molecular insight into complex fluid processing and high throughput characterisation

NASA Astrophysics Data System (ADS)

Lopez, Carlos; Watanabe, Takaichi; Cabral, Joao; Graham, Peter; Porcar, Lionel; Martel, Anne

2014-03-01

The coupling of microfluidics and small angle neutron scattering (SANS) is successfully demonstrated for the first time. We have developed novel microdevices with suitably low SANS background and high pressure compatibility for the investigation of flow-induced phenomena and high throughput phase mapping of complex fluids. We successfully obtained scattering profiles from 50 micron channels, in 10s - 100s second acquisition times. The microfluidic geometry enables the variation of both flow type and magnitude, beyond traditional rheo-SANS setups, and is exceptionally well-suited for complex fluids due to the commensurability of relevant time and lengthscales. We demonstrate our approach by studying model flow responsive systems, including surfactant/co-surfactant/water mixtures, with well-known equilibrium phase behaviour,: sodium dodecyl sulfate (SDS)/octanol/brine, cetyltrimethyl ammonium chloride (C16TAC)/pentanol/water and a model microemulsion system (C10E4 /decane/ D20), as well as polyelectrolyte solutions. Finally, using an online micromixer we are able to implement a high throughput approach, scanning in excess of 10 scattering profiles/min for a continuous aqueous surfactant dilution over two decades in concentration.

Biodegradation pathway of an anionic surfactant (Igepon TC-42) during recycling waste water through plant hydroponics for advanced life support during long-duration space missions

NASA Astrophysics Data System (ADS)

Levine, L. H.; Kagie, H. R.; Garland, J. L.

The degradation of an anionic surfactant (Igepon TC-42) was investigated as part of an integrated study of direct recycling of human hygiene water through hydroponic plant growth systems. Several chemical approaches were developed to characterize the degradation of Igepon and to measure the accumulation of intermediates such as fatty acids and methyl taurine. Igepon was rapidly degraded as indicated by the reduction of methylene blue active substances (MBAS) and component fatty acids. The Igepon degradation rate continued to increase over a period of several weeks following repeated daily exposure to 18 μg/l Igepon. The accumulation of free fatty acids and methyl taurine was also observed during decomposition of Igepon. The concentration of methyl taurine was below detection limit (0.2 nmol/ml) during the slow phase of Igepon degradation, and increased to 1-2 nmol/ml during the phase of rapid degradation. These findings support a degradation pathway involving initial hydrolysis of amide to release fatty acids and methyl taurine, and subsequent degradation of these intermediates.

[Case of young woman with Graves' disease and incomplete distal renal tubular acidosis with severe progress and cardiac arrest].

PubMed

Klimm, Wojciech; Kade, Grzegorz; Spaleniak, Sebastian; Dubchak, Ivanna; Niemczyk, Stanisław

2014-07-01

Diagnostic of renal tubular disorders can be often difficult. Incomplete form of distal Renal Tubular Acidosis (dRta) in course of Graves' disease was de novo recognized in a young woman hospitalized with a deep deficiency of potassium in blood serum complicated with cardiac arrest. Series of tests assessing the types and severity of water-electrolyte, acid-base and thyroid disorders were performed during a complex diagnosis. During the treatment of acute phase of the disease we intensified efforts to maintain basic life functions and to eliminate deep water-electrolyte disturbances. In the second phase of the treatment we determined an underlying cause of the disease, recognized dRTA, and introduced a specific long-term electrolyte and hormonal therapy. To confirm the diagnosis oral test with ammonium chloride (Wrong-Davies' test) was performed. After completion of the diagnostic and therapeutic process, the patient was included in the nephrological supervision on an outpatient basis. The basic drug for the therapy was sodium citrate. After a year of observation and continuing treatment we evaluated therapeutic results as good and permanent.

A multifunctional biphasic water splitting catalyst tailored for integration with high-performance semiconductor photoanodes

DOE PAGES

Yang, Jinhui; Cooper, Jason K.; Toma, Francesca M.; ...

2016-11-07

Artificial photosystems are advanced by the development of conformal catalytic materials that promote desired chemical transformations, while also maintaining stability and minimizing parasitic light absorption for integration on surfaces of semiconductor light absorbers. We demonstrate that multifunctional, nanoscale catalysts that enable high-performance photoelectrochemical energy conversion can be engineered by plasma-enhanced atomic layer deposition. The collective properties of tailored Co 3 O 4 /Co(OH) 2 thin films simultaneously provide high activity for water splitting, permit efficient interfacial charge transport from semiconductor substrates, and enhance durability of chemically sensitive interfaces. Furthermore, these films comprise compact and continuous nanocrystalline Co 3 O 4more » spinel that is impervious to phase transformation and impermeable to ions, thereby providing effective protection of the underlying substrate. Moreover, a secondary phase of structurally disordered and chemically labile Co(OH) 2 is introduced to ensure a high concentration of catalytically active sites. Application of this coating to photovoltaic p + n-Si junctions yields best reported performance characteristics for crystalline Si photoanodes.« less

Study the effect of polymers on the stability and rheological properties of oil-in-water (O/W) Pickering emulsion muds

NASA Astrophysics Data System (ADS)

Jha, Praveen Kumar; Mahto, Vikas; Saxena, Vinod Kumar

2018-05-01

A new type of oil-in-water (O/W) Pickering emulsion systems, which were prepared by polymers such as xanthan gum, carboxymethyl cellulose (CMC), and sodium lignosulfonate have been investigated for their properties as multifunctional emulsion muds with respect to rheological control and filtration control properties. Diesel oil was used as dispersed phase and KCl-brine as continuous phase in the developed emulsions. Initially, rheological parameters like apparent viscosity, plastic viscosity, gel strength, and filtration control properties were measured using recommended practices. Emulsion stability was analyzed using steady state shear stress-shear rate and oscillatory (dynamic) rheological measurement techniques. The emulsions were found to exhibit shear-thinning (pseudoplastic) behavior. Experiments conducted for oscillatory rheological measurements have shown that emulsions are stable as per the stability criteria G' (elastic modulus) > G'' (loss modulus) and both are independent of changing ω (Frequency). These fluids have shown stable properties upto 70°C which shows that they can be used as drilling muds for drilling oil and gas wells.

Understanding decomposition and encapsulation energies of structure I and II clathrate hydrates

NASA Astrophysics Data System (ADS)

Alavi, Saman; Ohmura, Ryo

2016-10-01

When compressed with water or ice under high pressure and low temperature conditions, some gases form solid gas hydrate inclusion compounds which have higher melting points than ice under those pressures. In this work, we study the balance of the guest-water and water-water interaction energies that lead to the formation of the clathrate hydrate phases. In particular, molecular dynamics simulations with accurate water potentials are used to study the energetics of the formation of structure I (sI) and II (sII) clathrate hydrates of methane, ethane, and propane. The dissociation enthalpy of the clathrate hydrate phases, the encapsulation enthalpy of methane, ethane, and propane guests in the corresponding phases, and the average bonding enthalpy of water molecules are calculated and compared with accurate calorimetric measurements and previous classical and quantum mechanical calculations, when available. The encapsulation energies of methane, ethane, and propane guests stabilize the small and large sI and sII hydrate cages, with the larger molecules giving larger encapsulation energies. The average water-water interactions are weakened in the sI and sII phases compared to ice. The relative magnitudes of the van der Waals potential energy in ice and the hydrate phases are similar, but in the ice phase, the electrostatic interactions are stronger. The stabilizing guest-water "hydrophobic" interactions compensate for the weaker water-water interactions and stabilize the hydrate phases. A number of common assumptions regarding the guest-cage water interactions are used in the van der Waals-Platteeuw statistical mechanical theory to predict the clathrate hydrate phase stability under different pressure-temperature conditions. The present calculations show that some of these assumptions may not accurately reflect the physical nature of the interactions between guest molecules and the lattice waters.

Understanding decomposition and encapsulation energies of structure I and II clathrate hydrates.

PubMed

Alavi, Saman; Ohmura, Ryo

2016-10-21

When compressed with water or ice under high pressure and low temperature conditions, some gases form solid gas hydrate inclusion compounds which have higher melting points than ice under those pressures. In this work, we study the balance of the guest-water and water-water interaction energies that lead to the formation of the clathrate hydrate phases. In particular, molecular dynamics simulations with accurate water potentials are used to study the energetics of the formation of structure I (sI) and II (sII) clathrate hydrates of methane, ethane, and propane. The dissociation enthalpy of the clathrate hydrate phases, the encapsulation enthalpy of methane, ethane, and propane guests in the corresponding phases, and the average bonding enthalpy of water molecules are calculated and compared with accurate calorimetric measurements and previous classical and quantum mechanical calculations, when available. The encapsulation energies of methane, ethane, and propane guests stabilize the small and large sI and sII hydrate cages, with the larger molecules giving larger encapsulation energies. The average water-water interactions are weakened in the sI and sII phases compared to ice. The relative magnitudes of the van der Waals potential energy in ice and the hydrate phases are similar, but in the ice phase, the electrostatic interactions are stronger. The stabilizing guest-water "hydrophobic" interactions compensate for the weaker water-water interactions and stabilize the hydrate phases. A number of common assumptions regarding the guest-cage water interactions are used in the van der Waals-Platteeuw statistical mechanical theory to predict the clathrate hydrate phase stability under different pressure-temperature conditions. The present calculations show that some of these assumptions may not accurately reflect the physical nature of the interactions between guest molecules and the lattice waters.

Correlation of porous and functional properties of food materials by NMR relaxometry and multivariate analysis.

PubMed

Haiduc, Adrian Marius; van Duynhoven, John

2005-02-01

The porous properties of food materials are known to determine important macroscopic parameters such as water-holding capacity and texture. In conventional approaches, understanding is built from a long process of establishing macrostructure-property relations in a rational manner. Only recently, multivariate approaches were introduced for the same purpose. The model systems used here are oil-in-water emulsions, stabilised by protein, and form complex structures, consisting of fat droplets dispersed in a porous protein phase. NMR time-domain decay curves were recorded for emulsions with varied levels of fat, protein and water. Hardness, dry matter content and water drainage were determined by classical means and analysed for correlation with the NMR data with multivariate techniques. Partial least squares can calibrate and predict these properties directly from the continuous NMR exponential decays and yields regression coefficients higher than 82%. However, the calibration coefficients themselves belong to the continuous exponential domain and do little to explain the connection between NMR data and emulsion properties. Transformation of the NMR decays into a discreet domain with non-negative least squares permits the use of multilinear regression (MLR) on the resulting amplitudes as predictors and hardness or water drainage as responses. The MLR coefficients show that hardness is highly correlated with the components that have T2 distributions of about 20 and 200 ms whereas water drainage is correlated with components that have T2 distributions around 400 and 1800 ms. These T2 distributions very likely correlate with water populations present in pores with different sizes and/or wall mobility. The results for the emulsions studied demonstrate that NMR time-domain decays can be employed to predict properties and to provide insight in the underlying microstructural features.

Concentration data for anthropogenic organic compounds in ground water, surface water, and finished water of selected community water systems in the United States, 2002-05

USGS Publications Warehouse

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

2007-01-01

The National Water-Quality Assessment Program of the U.S. Geological Survey began implementing Source Water-Quality Assessments (SWQAs) in 2001 that focus on characterizing the quality of source water and finished water of aquifers and major rivers used by some of the larger community water systems (CWSs) in the United States. As used for SWQA studies, source water is the raw (ambient) water collected at the supply well prior to water treatment (for ground water) or the raw (ambient) water collected from the river near the intake (for surface water), and finished water is the water that is treated and ready to be delivered to consumers. Finished water is collected before entering the distribution system. SWQA studies are conducted in two phases, and the objectives of SWQA studies are twofold: (1) to determine the occurrence and, for rivers, seasonal changes in concentrations of a broad list of anthropogenic organic compounds (AOCs) in aquifers and rivers that have some of the largest withdrawals for drinking-water supply (phase 1), and (2) for those AOCs found to occur most frequently in source water, characterize the extent to which these compounds are present in finished water (phase 2). These objectives were met for SWQA studies by collecting ground-water and surface-water (source) samples and analyzing these samples for 258 AOCs during phase 1. Samples from a subset of wells and surface-water sites located in areas with substantial agricultural production in the watershed were analyzed for 19 additional AOCs, for a total of 277 compounds analyzed for SWQA studies. The 277 compounds were classified according to the following 13 primary use or source groups: (1) disinfection by-products; (2) fumigant-related compounds; (3) fungicides; (4) gasoline hydrocarbons, oxygenates, and oxygenate degradates; (5) herbicides and herbicide degradates; (6) insecticides and insecticide degradates; (7) manufacturing additives; (8) organic synthesis compounds; (9) pavement- and combustion-derived compounds; (10) personal care and domestic use products; (11) plant- or animal-derived biochemicals; (12) refrigerants and propellants; and (13) solvents. Source and finished water samples were collected during phase 2 and analyzed for constituents that were detected frequently during phase 1. This report presents concentration data for AOCs in ground water, surface water, and finished water of CWSs sampled for SWQA studies during 2002-05. Specifically, this report presents the analytical results of samples collected during phase 1 including (1) samples from 221 wells that were analyzed for 258 AOCs; (2) monthly samples from 9 surface-water sites that were analyzed for 258 AOCs during phase 1; and (3) samples from a subset of the wells and surface-water sites located in areas with substantial agricultural production that were analyzed for 3 additional pesticides and 16 pesticide degradates. Samples collected during phase 2 were analyzed for selected AOCs that were detected most frequently in source water during phase 1 sampling; analytical results for phase 2 are presented for (1) samples of source water and finished water from 94 wells; and (2) samples of source water and finished water samples that were collected monthly and during selected flow conditions at 8 surface-water sites. Results of quality-assurance/quality-control samples collected for SWQA studies during 2002-05 also are presented.

Space Station Freedom Water Recovery test total organic carbon accountability

NASA Technical Reports Server (NTRS)

Davidson, Michael W.; Slivon, Laurence; Sheldon, Linda; Traweek, Mary

1991-01-01

Marshall Space Flight Center's (MSFC) Water Recovery Test (WRT) addresses the concept of integrated hygiene and potable reuse water recovery systems baselined for Space Station Freedom (SSF). To assess the adequacy of water recovery system designs and the conformance of reclaimed water quality to established specifications, MSFC has initiated an extensive water characterization program. MSFC's goal is to quantitatively account for a large percentage of organic compounds present in waste and reclaimed hygiene and potable waters from the WRT and in humidity condensate from Spacelab missions. The program is coordinated into Phase A and B. Phase A's focus is qualitative and semi-quantitative. Precise quantitative analyses are not emphasized. Phase B's focus centers on a near complete quantitative characterization of all water types. Technical approaches along with Phase A and partial Phase B investigations on the compositional analysis of Total Organic Carbon (TOC) Accountability are presented.

Design and application of water-in-oil emulsions for use in lipstick formulations.

PubMed

Le Révérend, B J D; Taylor, M S; Norton, I T

2011-06-01

The addition of water to lipsticks in the form of a water-in-oil emulsion is an attractive opportunity for cosmetics manufacturers to deliver hydrophilic molecules to the consumers, as well as improving the moisturizing properties. In this work, the effect of the emulsifier type and water content on the structural properties of the designed products was investigated. It has been shown that PGPR leads to smaller droplets than the other emulsifiers tested. This was attributed to the ability of PGPR to form elastic interfaces that slow the coalescence between droplets during the process. It was also observed that crystals of wax tend to form structures at the interface upon cooling that prevent coalescence during storage. These structures also prevent leakage of water into the continuous phase. No effect of the water content on the melting properties of the emulsions was observed. Upon addition of more than 10% water, softening of the material was measured, due to the overall decrease in solid content. Addition of crystalline material (hard paraffin) was successfully used to reinstate the material properties. © 2011 The Authors. ICS © 2011 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

Boiling vapour-type fluids from the Nifonea vent field (New Hebrides Back-Arc, Vanuatu, SW Pacific): Geochemistry of an early-stage, post-eruptive hydrothermal system

NASA Astrophysics Data System (ADS)

Schmidt, Katja; Garbe-Schönberg, Dieter; Hannington, Mark D.; Anderson, Melissa O.; Bühring, Benjamin; Haase, Karsten; Haruel, Christy; Lupton, John; Koschinsky, Andrea

2017-06-01

In 2013, high-temperature vent fluids were sampled in the Nifonea vent field. This field is located within the caldera of a large shield-type volcano of the Vate Trough, a young extensional rift in the New Hebrides back-arc. Hydrothermal venting occurs as clear and black smoker fluids with temperatures up to 368 °C, the hottest temperatures measured so far in the western Pacific. The physico-chemical conditions place the fluids within the two-phase field of NaCl-H2O, and venting is dominated by vapour phase fluids with Cl concentrations as low as 25 mM. The fluid composition, which differs between the individual vent sites, is interpreted to reflect the specific geochemical fluid signature of a hydrothermal system in its initial, post-eruptive stage. The strong Cl depletion is accompanied by low alkali/Cl ratios compared to more evolved hydrothermal systems, and very high Fe/Cl ratios. The concentrations of REY (180 nM) and As (21 μM) in the most Cl-depleted fluid are among the highest reported so far for submarine hydrothermal fluids, whereas the inter-element REY fractionation is only minor. The fluid signature, which has been described here for the first time in a back-arc setting, is controlled by fast fluid passage through basaltic volcanic rocks, with extremely high water-rock ratios and only limited water-rock exchange, phase separation and segregation, and (at least) two-component fluid mixing. Metals and metalloids are unexpectedly mobile in the vapour phase fluids, and the strong enrichments of Fe, REY, and As highlight the metal transport capacity of low-salinity, low-density vapours at the specific physico-chemical conditions at Nifonea. One possible scenario is that the fluids boiled before the separated vapour phase continued to react with fresh glassy lavas. The mobilization of metals is likely to occur by leaching from fresh glass and grain boundaries and is supported by the high water/rock ratios. The enrichment of B and As is further controlled by their high volatility, whereas the strong enrichment of REY is also a consequence of the elevated concentrations in the host rocks. However, a direct contribution of metals such as As from magmatic degassing cannot be ruled out. The different fluid end-member composition of individual vent sites could be explained by mixing of vapour phase fluids with another fluid phase of different water/rock interaction history.

Microscopic Analysis of Current and Mechanical Properties of Nafion® Studied by Atomic Force Microscopy

PubMed Central

Hiesgen, Renate; Helmly, Stefan; Galm, Ines; Morawietz, Tobias; Handl, Michael; Friedrich, K. Andreas

2012-01-01

The conductivity of fuel cell membranes as well as their mechanical properties at the nanometer scale were characterized using advanced tapping mode atomic force microscopy (AFM) techniques. AFM produces high-resolution images under continuous current flow of the conductive structure at the membrane surface and provides some insight into the bulk conducting network in Nafion membranes. The correlation of conductivity with other mechanical properties, such as adhesion force, deformation and stiffness, were simultaneously measured with the current and provided an indication of subsurface phase separations and phase distribution at the surface of the membrane. The distribution of conductive pores at the surface was identified by the formation of water droplets. A comparison of nanostructure models with high-resolution current images is discussed in detail. PMID:24958429

48 CFR 2152.237-70 - Continuity of services.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Government or another Contractor, may continue them. The Contractor agrees to furnish phase-in training and...) The Contractor shall, upon the Contracting Officer's written notice, (1) furnish phase-in and phase... with a successor to determine the nature and extent of phase-in and phase-out services required. The...

In-situ continuous water monitoring system

DOEpatents

Thompson, Cyril V.; Wise, Marcus B.

1998-01-01

An in-situ continuous liquid monitoring system for continuously analyzing volatile components contained in a water source comprises: a carrier gas supply, an extraction container and a mass spectrometer. The carrier gas supply continuously supplies the carrier gas to the extraction container and is mixed with a water sample that is continuously drawn into the extraction container by the flow of carrier gas into the liquid directing device. The carrier gas continuously extracts the volatile components out of the water sample. The water sample is returned to the water source after the volatile components are extracted from it. The extracted volatile components and the carrier gas are delivered continuously to the mass spectrometer and the volatile components are continuously analyzed by the mass spectrometer.

In-situ continuous water monitoring system

DOEpatents

Thompson, C.V.; Wise, M.B.

1998-03-31

An in-situ continuous liquid monitoring system for continuously analyzing volatile components contained in a water source comprises: a carrier gas supply, an extraction container and a mass spectrometer. The carrier gas supply continuously supplies the carrier gas to the extraction container and is mixed with a water sample that is continuously drawn into the extraction container by the flow of carrier gas into the liquid directing device. The carrier gas continuously extracts the volatile components out of the water sample. The water sample is returned to the water source after the volatile components are extracted from it. The extracted volatile components and the carrier gas are delivered continuously to the mass spectrometer and the volatile components are continuously analyzed by the mass spectrometer. 2 figs.

Biopolymer-based structuring of liquid oil into soft solids and oleogels using water-continuous emulsions as templates.

PubMed

Patel, Ashok R; Rajarethinem, Pravin S; Cludts, Nick; Lewille, Benny; De Vos, Winnok H; Lesaffer, Ans; Dewettinck, Koen

2015-02-24

Physical trapping of a hydrophobic liquid oil in a matrix of water-soluble biopolymers was achieved using a facile two-step process by first formulating a surfactant-free oil-in-water emulsion stabilized by biopolymers (a protein and a polysaccharide) followed by complete removal of the water phase (by either high- or low-temperature drying of the emulsion) resulting in structured solid systems containing a high concentration of liquid oil (above 97 wt %). The microstructure of these systems was revealed by confocal and cryo-scanning electron microscopy, and the effect of biopolymer concentrations on the consistency of emulsions as well as the dried product was evaluated using a combination of small-amplitude oscillatory shear rheometry and large deformation fracture studies. The oleogel prepared by shearing the dried product showed a high gel strength as well as a certain degree of thixotropic recovery even at high temperatures. Moreover, the reversibility of the process was demonstrated by shearing the dried product in the presence of water to obtain reconstituted emulsions with rheological properties comparable to those of the fresh emulsion.

Influential factors of formation kinetics of flocs produced by water treatment coagulants.

PubMed

Wu, Chunde; Wang, Lin; Hu, Bing; Ye, Jian

2013-05-01

The growth rate and size of floc formation is of great importance in water treatment especially in coagulation process. The floc formation kinetics and the coagulation efficiency of synthetic water were investigated by using an on-line continuous optical photometric dispersion analyze and the analysis of water quality. Experimental conditions such as alum dosage, pH value for coagulation, stirring intensity and initial turbidity were extensively examined. The photometric dispersion analyze results showed that coagulation of kaolin suspensions with two coagulants (alum and polyaluminium chloride) could be taken as a two-phase process: slow and rapid growth periods. Operating conditions with higher coagulant doses, appropriate pH and average shear rate might be particularly advantageous. The rate of overall floc growth was mainly determined by a combination of hydraulic and water quality conditions such as pH and turbidity. The measurement of zeta potential indicates that polyaluminium chloride exhibited higher charge-neutralizing ability than alum and achieved lower turbidities than alum for equivalent Al dosages. Under the same operating conditions, the alum showed a higher grow rate, but with smaller floc size.

Comparing microbial water quality in an intermittent and continuous piped water supply.

PubMed

Kumpel, Emily; Nelson, Kara L

2013-09-15

Supplying piped water intermittently is a common practice throughout the world that increases the risk of microbial contamination through multiple mechanisms. Converting an intermittent supply to a continuous supply has the potential to improve the quality of water delivered to consumers. To understand the effects of this upgrade on water quality, we tested samples from reservoirs, consumer taps, and drinking water provided by households (e.g. from storage containers) from an intermittent and continuous supply in Hubli-Dharwad, India, over one year. Water samples were tested for total coliform, Escherichia coli, turbidity, free chlorine, and combined chlorine. While water quality was similar at service reservoirs supplying the continuous and intermittent sections of the network, indicator bacteria were detected more frequently and at higher concentrations in samples from taps supplied intermittently compared to those supplied continuously (p < 0.01). Detection of E. coli was rare in continuous supply, with 0.7% of tap samples positive compared to 31.7% of intermittent water supply tap samples positive for E. coli. In samples from both continuously and intermittently supplied taps, higher concentrations of total coliform were measured after rainfall events. While source water quality declined slightly during the rainy season, only tap water from intermittent supply had significantly more indicator bacteria throughout the rainy season compared to the dry season. Drinking water samples provided by households in both continuous and intermittent supplies had higher concentrations of indicator bacteria than samples collected directly from taps. Most households with continuous supply continued to store water for drinking, resulting in re-contamination, which may reduce the benefits to water quality of converting to continuous supply. Copyright © 2013 Elsevier Ltd. All rights reserved.

Doping-induced disappearance of ice II from water's phase diagram

NASA Astrophysics Data System (ADS)

Shephard, Jacob J.; Slater, Ben; Harvey, Peter; Hart, Martin; Bull, Craig L.; Bramwell, Steven T.; Salzmann, Christoph G.

2018-06-01

Water and the many phases of ice display a plethora of complex physical properties and phase relationships1-4 that are of paramount importance in a range of settings including processes in Earth's hydrosphere, the geology of icy moons, industry and even the evolution of life. Well-known examples include the unusual behaviour of supercooled water2, the emergent ferroelectric ordering in ice films4 and the fact that the `ordinary' ice Ih floats on water. We report the intriguing observation that ice II, one of the high-pressure phases of ice, disappears in a selective fashion from water's phase diagram following the addition of small amounts of ammonium fluoride. This finding exposes the strict topologically constrained nature of the ice II hydrogen-bond network, which is not found for the competing phases. In analogy to the behaviour of frustrated magnets5, the presence of the exceptional ice II is argued to have a wider impact on water's phase diagram, potentially explaining its general tendency to display anomalous behaviour. Furthermore, the impurity-induced disappearance of ice II raises the prospect that specific dopants may not only be able to suppress certain phases but also induce the formation of new phases of ice in future studies.

Phase equilibrium in a water + n-hexane system with a high water content

NASA Astrophysics Data System (ADS)

Rasulov, S. M.; Orakova, S. M.; Isaev, Z. A.

2017-02-01

The P, ρ, and T-properties of a water + n-hexane system immiscible under normal conditions are measured piezometrically in the water mole fraction range of 0.918-0.977 at 309-685 K and pressures of up to 66 MPa. Two phase transitions are observed on each isochore corresponding to phase transitions of hydrocarbon liquid into gas or the dissolution of n-hexane in water and the transition of aqueous liquid into gas. The boundaries of phase transitions and their critical parameters are determined.

Enhanced percutaneous permeability of diclofenac using a new U-type dilutable microemulsion.

PubMed

Shevachman, Marina; Garti, Nissim; Shani, Arnon; Sintov, Amnon C

2008-04-01

Enhanced systemic absorption in vivo and percutaneous penetration in vitro was demonstrated after transdermal administration of diclofenac sodium formulated in U-type microemulsion. Diclofenac sodium was solubilized in a typical four-component system consisting of an oil, polyoxyethylene-10EO-oleyl alcohol (Brij 96V) as the surfactant, and 1-hexanol along water dilution line W46 (40 wt % surfactant and 60 wt % oil phase before water titration). Viscosity and small angle X-ray scattering measurements have evidenced bicontinuous structures within water fractions of 0.25 and 0.5 along the dilution line. Self-diffusion NMR studies showed that drug molecules accumulated in the interfacial film and, to some extent, dissolved in the oil. Relative to a commercial macro-emulsion cream (Voltaren Emulgel), microemulsions containing paraffin oil or isopropyl myristate increased the in vivo transdermal penetration rate of diclofenac by two order of magnitude, whereas the rat plasma levels were increased by one order of magnitude. The in vitro data obtained from excised rat skin were comparable to the in vivo results, but suffered from discrepancies from the ideal in vivo-in vitro correlation, which might be explained by optimal in vitro conditions of perfusion and hydration. It has also been found that when jojoba oil is formulated as the oil phase in the microemulsion, the penetration rate of the drug decreases significantly. Based on the three-dimensional structure of jojoba oil, the wax is presumed to prevent the drug from being freely diffused into the skin while migrating from the interfacial film into the continuous oil phase.

The catalytic role of water in the photochemistry of ammonia ice: from diluted to concentrated phase

NASA Astrophysics Data System (ADS)

Jonusas, Mindaugas; Krim, Lahouari

2017-10-01

Using infrared spectroscopy as an in situ probe for reactions occurring in the solid phase, we investigated the influence of water molecules on the photochemistry of ammonia ices. Experiments were carried out in diluted and concentrated phases and between 3 and 130 K. We showed that the photolysis of NH3-H2O (2 per cent of H2O) ices using continuous radiation from 115 to 400 nm produces NH2OH as the main photoproduct, but also that such a photoinduced reaction strongly depends on both the initial ice temperature and the environment where the primary reactants NH3 and H2O are trapped. Our experimental results highlight the catalytic role played by H2O molecules in enhancing the formation yield of NH2 during the photolysis process through the NH3 + OH → NH2 + H2O hydrogen abstraction reaction, which is only favored at low temperatures in the range of 3-60 K. During heating of such irradiated ammonia-water ices, the amount of NH2OH keeps rising while that of NH2, is greatly reduced only from 70 K onwards. These behaviours are attributed to the competition that occurs between NH2 formation from the NH3 + OH reaction and its consumption from the NH2 + OH radical recombination. These results might explain the variable abundances of NH2 and NH3 provided by previous astronomical observations, where the NH2/NH3 ratio ranges from 0.02 to 0.5 depending on the regions of the interstellar medium that were analysed.

Inorganic chemistry of water and bed sediment in selected tributaries of the south Umpqua River, Oregon, 1998

USGS Publications Warehouse

Hinkle, Stephen R.

1999-01-01

Ten sites on small South Umpqua River tributaries were sampled for inorganic constituents in water and streambed sediment. In aqueous samples, high concentrations (concentrations exceeding U.S. Environmental Protection Agency criterion continuous concentration for the protection of aquatic life) of zinc, copper, and cadmium were detected in Middle Creek at Silver Butte, and the concentration of zinc was high at Middle Creek near Riddle. Similar patterns of trace-element occurrence were observed in streambed-sediment samples.The dissolved aqueous load of zinc carried by Middle Creek along the stretch between the upper site (Middle Creek at Silver Butte) and the lower site (Middle Creek near Riddle) decreased by about 0.3 pounds per day. Removal of zinc from solution between the upper and lower sites on Middle Creek evidently was occurring at the time of sampling. However, zinc that leaves the aqueous phase is not necessarily permanently lost from solution. For example, zinc solubility is pH-dependent, and a shift between solid and aqueous phases towards release of zinc to solution in Middle Creek could occur with a perturbation in stream-water pH. Thus, at least two potentially significant sources of zinc may exist in Middle Creek: (1) the upstream source(s) producing the observed high aqueous zinc concentrations and (2) the streambed sediment itself (zinc-bearing solid phases and/or adsorbed zinc). Similar behavior may be exhibited by copper and cadmium because these trace elements also were present at high concentrations in streambed sediment in the Middle Creek Basin.

ENVIRONMENTAL STEWARDSHIP OF PHARMACEUTICALS ...

EPA Pesticide Factsheets

The occurrence of pharmaceuticals and personal care products (PPCPS) as environmental pollutants is a multifaceted issue whose scope continues to become better delineated since the escalation of conceited attention beginning in the 1980s. PPCPs typically occur as trace environmental pollutants (primarily in surface but also in ground waters) as a result of their widespread, continuous, combined usage in a broad range of human and veterinary therapeutic activities and practices. With respect to the risk-assessment paradigm the growing body of published work has focused primarily on the origin and occurrence of these substances. Comparatively less is known about human and ecological exposure, and even less about the documented or potential hazards associated with trace exposure to these anthropogenic substances, many of which are highly bioactive and perpetually present in many aquatic locales. The research focused on in the subtasks is the development and application of state-of the-art technologies to meet the needs of the public, Office of Water, and ORD in the area of Water Quality. Located In the subtasks are the various research projects being performed in support of this Task and more in-depth coverage of each project. Briefly, each project's objective is stated below.Subtask 1: To integrate state-of-the-art technologies (polar organic chemical integrative samplers, advanced solid-phase extraction methodologies with liquid chromatography/electrospray/m

Basis for the development of sustainable optimisation indicators for activated sludge wastewater treatment plants in the Republic of Ireland.

PubMed

Gordon, G T; McCann, B P

2015-01-01

This paper describes the basis of a stakeholder-based sustainable optimisation indicator (SOI) system to be developed for small-to-medium sized activated sludge (AS) wastewater treatment plants (WwTPs) in the Republic of Ireland (ROI). Key technical publications relating to best practice plant operation, performance audits and optimisation, and indicator and benchmarking systems for wastewater services are identified. Optimisation studies were developed at a number of Irish AS WwTPs and key findings are presented. A national AS WwTP manager/operator survey was carried out to verify the applied operational findings and identify the key operator stakeholder requirements for this proposed SOI system. It was found that most plants require more consistent operational data-based decision-making, monitoring and communication structures to facilitate optimised, sustainable and continuous performance improvement. The applied optimisation and stakeholder consultation phases form the basis of the proposed stakeholder-based SOI system. This system will allow for continuous monitoring and rating of plant performance, facilitate optimised operation and encourage the prioritisation of performance improvement through tracking key operational metrics. Plant optimisation has become a major focus due to the transfer of all ROI water services to a national water utility from individual local authorities and the implementation of the EU Water Framework Directive.

Critical size of crystalline ZrO(2) nanoparticles synthesized in near- and supercritical water and supercritical isopropyl alcohol.

PubMed

Becker, Jacob; Hald, Peter; Bremholm, Martin; Pedersen, Jan S; Chevallier, Jacques; Iversen, Steen B; Iversen, Bo B

2008-05-01

Nanocrystalline ZrO(2) samples with narrow size distributions and mean particle sizes below 10 nm have been synthesized in a continuous flow reactor in near and supercritical water as well as supercritical isopropyl alcohol using a wide range of temperatures, pressures, concentrations and precursors. The samples were comprehensively characterized by powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), and small-angle X-ray scattering (SAXS), and the influence of the synthesis parameters on the particle size, particle size distribution, shape, aggregation and crystallinity was studied. On the basis of the choice of synthesis parameters either monoclinic or tetragonal zirconia phases can be obtained. The results suggest a critical particle size of 5-6 nm for nanocrystalline monoclinic ZrO(2) under the present conditions, which is smaller than estimates reported in the literature. Thus, very small monoclinic ZrO(2) particles can be obtained using a continuous flow reactor. This is an important result with respect to improvement of the catalytic properties of nanocrystalline ZrO(2).

Enhanced mobility of non aqueous phase liquid (NAPL) during drying of wet sand

NASA Astrophysics Data System (ADS)

Govindarajan, Dhivakar; Deshpande, Abhijit P.; Raghunathan, Ravikrishna

2018-02-01

Enhanced upward mobility of a non aqueous phase liquid (NAPL) present in wet sand during natural drying, and in the absence of any external pressure gradients, is reported for the first time. This mobility was significantly higher than that expected from capillary rise. Experiments were performed in a glass column with a small layer of NAPL-saturated sand trapped between two layers of water-saturated sand. Drying of the wet sand was induced by flow of air across the top surface of the wet sand. The upward movement of the NAPL, in the direction of water transport, commenced when the drying effect reached the location of the NAPL and continued as long as there was significant water evaporation in the vicinity of NAPL, indicating a clear correlation between the NAPL rise and water evaporation. The magnitude and the rate of NAPL rise was measured at different water evaporation rates, different initial locations of the NAPL, different grain size of the sand and the type of NAPL (on the basis of different NAPL-glass contact angle, viscosity and density). A positive correlation was observed between average rate of NAPL rise and the water evaporation while a negative correlation was obtained between the average NAPL rise rate and the NAPL properties of contact angle, viscosity and density. There was no significant correlation of average NAPL rise rate with variation of sand grain size between 0.1 to 0.5 mm. Based on these observations and on previous studies reported in the literature, two possible mechanisms are hypothesized -a) the effect of the spreading coefficient resulting in the wetting of NAPL on the water films created and b) a moving water film due to evaporation that "drags" the NAPL upwards. The NAPL rise reported in this paper has implications in fate and transport of chemicals in NAPL contaminated porous media such as soils and exposed dredged sediment material, which are subjected to varying water saturation levels due to drying and rewetting.

Constitutive equations for an electroactive polymer

NASA Astrophysics Data System (ADS)

Tixier, Mireille; Pouget, Joël

2016-07-01

Ionic electroactive polymers can be used as sensors or actuators. For this purpose, a thin film of polyelectrolyte is saturated with a solvent and sandwiched between two platinum electrodes. The solvent causes a complete dissociation of the polymer and the release of small cations. The application of an electric field across the thickness results in the bending of the strip and vice versa. The material is modeled by a two-phase continuous medium. The solid phase, constituted by the polymer backbone inlaid with anions, is depicted as a deformable porous media. The liquid phase is composed of the free cations and the solvent (usually water). We used a coarse grain model. The conservation laws of this system have been established in a previous work. The entropy balance law and the thermodynamic relations are first written for each phase and then for the complete material using a statistical average technique and the material derivative concept. One deduces the entropy production. Identifying generalized forces and fluxes provides the constitutive equations of the whole system: the stress-strain relations which satisfy a Kelvin-Voigt model, generalized Fourier's and Darcy's laws and the Nernst-Planck equation.

University of Minnesota Aquifer Thermal Energy Storage (ATES) project report on the first long-term cycle

NASA Astrophysics Data System (ADS)

Walton, M.

1991-10-01

The technical feasibility of high-temperature (greater than 100 C) aquifer thermal energy storage (IOTAS) in a deep, confined aquifer was tested in a series of experimental cycles at the University of Minnesota's St. Paul field test facility (FTF). This report describes the additions to the FTF for the long-term cycles and the details of the first long-term cycle (LT1) that was conducted from November 1984 through May 1985. Heat recovery; operational experience; and thermal, chemical, hydrologic, and geologic aspects of LT1 are reported. The permits for long-term cycles required the addition of a monitoring well 30.5 m from the storage well for monitoring near the edge of the thermally affected area and allowed the addition of a cation-exchange water softener to enable continuous operation during the injection phase. Approximately 62 percent of the 9.47 GWh of energy added to the 9.21 x 10(exp 4) cu m of ground water stored in the aquifer LT1 was recovered. Ion-exchange water softening of the heated and stored ground water prevented scaling in the system heat exchangers and the storage well and changed the major-ion chemistry of the stored water. Temperatures at the storage horizons in site monitoring wells reached as high as 108 C during the injection phase of LT1. Following heat recovery, temperatures were less than 30 C at the same locations. Less permeable horizons underwent slow temperature changes. No thermal or chemical effects were observed at the remote monitoring site.

Understanding the contribution of phytoplankton phase functions to uncertainties in the water colour signal.

PubMed

Lain, Lisl Robertson; Bernard, Stewart; Matthews, Mark W

2017-02-20

The accurate description of a water body's volume scattering function (VSF), and hence its phase functions, is critical to the determination of the constituent inherent optical properties (IOPs), the associated spectral water-leaving reflectance, and consequently the retrieval of phytoplankton functional type (PFT) information. The equivalent algal populations (EAP) model has previously been evaluated for phytoplankton-dominated waters, and offers the ability to provide phytoplankton population-specific phase functions, unveiling a new opportunity to further understanding of the causality of the PFT signal. This study presents and evaluates the wavelength dependent, spectrally variable EAP particle phase functions and the subsequent effects on water-leaving reflectance. Comparisons are made with frequently used phase function approximations e.g. the Fournier Forand formulation, as well as with phase functions inferred from measured VSFs in coastal waters. Relative differences in shape and magnitude are quantified. Reflectance modelled with the EAP phase functions is then compared against measured reflectance data from phytoplankton-dominated waters. Further examples of modelled phytoplankton-dominated waters are discussed with reference to choice of phase function for two PFTs (eukaryote and prokaryote) across a range of biomass. Finally a demonstration of the sensitivity of reflectance due to the choice of phase function is presented. The EAP model phase functions account for both spectral and angular variability in phytoplankton backscattering i.e. they display variability which is both spectral and shape-related. It is concluded that phase functions modelled in this way are necessary for investigating the effects of assemblage variability on the ocean colour signal, and should be considered for model closure even in relatively low scattering conditions where phytoplankton dominate the IOPs.

Periodic cycle of stretching and breaking of the head of gravity currents

NASA Astrophysics Data System (ADS)

Nogueira, H. I. S.; Adduce, C.; Alves, E.; Franca, M. J.

2012-04-01

Gravity currents, which are geophysical flows driven by density differences within a fluid, are herein investigated under unsteady conditions by means of lock-exchange releases of saline water into a fresh water tank. Generally, gravity or density currents are caused by temperature differences or the presence of dissolved substances or particles in suspension. Examples of gravity currents include avalanches of airborne snow and plumes of pyroclasts from volcanic eruptions, in the atmosphere, releases of pollutants and turbidity currents, in rivers, lakes and reservoirs, and oil spillage and oceanic fronts in the ocean. A controlled and convenient fashion to investigate in detail hydrodynamics of unsteady gravity currents is by means of lock-exchange experiments. The propagation of unsteady density currents, produced by lock exchange experiments, present three distinct phases, a first so-called slumping phase when buoyancy and inertial effects are balanced and front celerity is constant, a second (self-similar) phase when the reflected bore from the upper layer ambient fluid upstream drive, caused by continuity within the limited length tank, reaches the current front and causes the front celerity to decrease and provokes a diminution of the current head and, finally, a third viscous phase when viscosity plays a role and its effects overcome inertial effects. On the first and second phase, the current propagation is ruled by buoyancy effects counterbalanced by inertia, Reynolds stresses on the upper mixing layer and bed shear. Buoyancy is reduced due to entrainment and consequently the front velocity, leading to lower Reynolds number flows allowing thus viscosity effects to play a role. As for its anatomy, the current presents two distinct regions, the head and the remaining body or tail. On the very first instants of the release, the flow is bulky driven by the whole current mass while the head is not yet well defined. Later, this detaches from the main body and its particular buoyancy drives the advance of the current, with a different celerity from the tail. The head is highly concentrated being the main engine of convection of the released mass, being subjected to entrainment at the interface with the ambient fluid. The aim of the present work is to experimentally investigate the dynamics of the head, including continuous entrainment and cycles of stretching and breaking observed in the laboratory. Experiments were conducted at the Laboratory of Hydraulics of University of Rome "Roma Tre" in a 3.0 m long, 0.20 m wide and 0.30 m deep transparent Perspex flume. Four lock-exchange release tests were performed varying the density of the saline water. For smooth bed and for a fixed value of water depth, h = 0.20 m, the following four different initial densities of the salt-water mixture were analysed: 1015, 1030, 1045 and 1060 kg/m3. A controlled quantity of dye is added to the saline water in the lock to provide flow visualization and to serve as density tracer. The development of the current is recorded with a 25 Hz CCD camera under controlled light conditions. The resulting video frames are thus converted into grey scale matrices and a calibration procedure establishes a non-linear relation, experimentally determined, between the gray scale values and the quantity of dye in the water. The quantity of dye is converted into salt concentration by assuming a linear relation between quantities, dye and salt, allowing thus the estimation of the 2D instantaneous current density distribution. The experiments allowed the observation of the dynamics of the head of unsteady density currents in detail, including a cyclic increase in dimension and mass due to entrainment followed by a division in two distinct patches. A frontal one continues the drive downstream whereas a subsequent one is left behind and incorporated in the tail, thus indicating that the loss of saline mass in the head is not only due to continuous entrainment at the interface layer. Entrainment follows a decaying trend along the current development whereas periodic division of the head seems to be kept. The division of the head is related to mass ejections directing upstream with a clear signature in the current-depth time and spatial evolution maps. Initial density of the released saline current seems to be related to the period of the cyclic division of the head and the amplitude of the mentioned mass ejections; averaged periods of the occurrence of the divisions are 3.40, 1.63, 1.07 and 0.91 s respectively for initial densities of the salt-water mixture corresponding to 1015, 1030, 1045 and 1060 kg/m3. Research supported by Portuguese Foundation for Science and Technology through the research project PTDC/ECM/099752/2008 and the PhD grant SFRH/BD/48705/2008.

OC5 Project Phase Ib: Validation of hydrodynamic loading on a fixed, flexible cylinder for offshore wind applications

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

Robertson, Amy N.; Wendt, Fabian; Jonkman, Jason M.

This paper summarizes the findings from Phase Ib of the Offshore Code Comparison, Collaboration, Continued with Correlation (OC5) project. OC5 is a project run under the International Energy Agency (IEA) Wind Research Task 30, and is focused on validating the tools used for modelling offshore wind systems through the comparison of simulated responses of select offshore wind systems (and components) to physical test data. For Phase Ib of the project, simulated hydrodynamic loads on a flexible cylinder fixed to a sloped bed were validated against test measurements made in the shallow water basin at the Danish Hydraulic Institute (DHI) withmore » support from the Technical University of Denmark (DTU). The first phase of OC5 examined two simple cylinder structures (Phase Ia and Ib) to focus on validation of hydrodynamic models used in the various tools before moving on to more complex offshore wind systems and the associated coupled physics. As a result, verification and validation activities such as these lead to improvement of offshore wind modelling tools, which will enable the development of more innovative and cost-effective offshore wind designs.« less

OC5 Project Phase Ib: Validation of hydrodynamic loading on a fixed, flexible cylinder for offshore wind applications

DOE PAGES

Robertson, Amy N.; Wendt, Fabian; Jonkman, Jason M.; ...

2016-10-13

This paper summarizes the findings from Phase Ib of the Offshore Code Comparison, Collaboration, Continued with Correlation (OC5) project. OC5 is a project run under the International Energy Agency (IEA) Wind Research Task 30, and is focused on validating the tools used for modelling offshore wind systems through the comparison of simulated responses of select offshore wind systems (and components) to physical test data. For Phase Ib of the project, simulated hydrodynamic loads on a flexible cylinder fixed to a sloped bed were validated against test measurements made in the shallow water basin at the Danish Hydraulic Institute (DHI) withmore » support from the Technical University of Denmark (DTU). The first phase of OC5 examined two simple cylinder structures (Phase Ia and Ib) to focus on validation of hydrodynamic models used in the various tools before moving on to more complex offshore wind systems and the associated coupled physics. As a result, verification and validation activities such as these lead to improvement of offshore wind modelling tools, which will enable the development of more innovative and cost-effective offshore wind designs.« less

Melting of the Dipalmitoylphosphatidylcholine Monolayer.

PubMed

Xu, Lu; Bosiljevac, Gordon; Yu, Kyle; Zuo, Yi Y

2018-04-17

Langmuir monolayer self-assembled at the air-water interface represents an excellent model for studying phase transition and lipid polymorphism in two dimensions. Compared with numerous studies of phospholipid phase transitions induced by isothermal compression, there are very scarce reports on two-dimensional phase transitions induced by isobaric heating. This is mainly due to technical difficulties of continuously regulating temperature variations while maintaining a constant surface pressure in a classical Langmuir-type film balance. Here, with technological advances in constrained drop surfactometry and closed-loop axisymmetric drop shape analysis, we studied the isobaric heating process of the dipalmitoylphosphatidylcholine (DPPC) monolayer. It is found that temperature and surface pressure are two equally important intensive properties that jointly determine the phase behavior of the phospholipid monolayer. We have determined a critical point of the DPPC monolayer at a temperature of 44 °C and a surface pressure of 57 mN/m. Beyond this critical point, no phase transition can exist in the DPPC monolayer, either by isothermal compression or by isobaric heating. The melting process of the DPPC monolayer studied here provides novel insights into the understanding of a wide range of physicochemical and biophysical phenomena, such as surface thermodynamics, critical phenomena, and biophysical study of pulmonary surfactants.

48 CFR 52.237-3 - Continuity of Services.

Code of Federal Regulations, 2011 CFR

2011-10-01

... the Government or another contractor, may continue them. The Contractor agrees to (1) furnish phase-in... phase-in, phase-out services for up to 90 days after this contract expires and (2) negotiate in good faith a plan with a successor to determine the nature and extent of phase-in, phase-out services...

48 CFR 52.237-3 - Continuity of Services.

Code of Federal Regulations, 2010 CFR

2010-10-01

... the Government or another contractor, may continue them. The Contractor agrees to (1) furnish phase-in... phase-in, phase-out services for up to 90 days after this contract expires and (2) negotiate in good faith a plan with a successor to determine the nature and extent of phase-in, phase-out services...

Mutagenicity and estrogenicity of raw water and drinking water in an industrialized city in the Yangtze River Delta.

PubMed

Xiao, Sanhua; Lv, Xuemin; Zeng, Yifan; Jin, Tao; Luo, Lan; Zhang, Binbin; Zhang, Gang; Wang, Yanhui; Feng, Lin; Zhu, Yuan; Tang, Fei

2017-10-01

Public concern was aroused by frequently reported water pollution incidents in Taihu Lake and the Yangtze River. The pollution also caught and sustained the attention of the scientific community. From 2010 to 2016, raw water and drinking water samples were continually collected at Waterworks A and B (Taihu Lake) and Waterworks C (Yangtze River). The non-volatile organic pollutants in the water samples were extracted by solid phase extraction. Ames tests and yeast estrogen screen (YES) assays were conducted to evaluate the respective mutagenic and estrogenic effects. Water samples from the Yangtze River-based Waterworks C possessed higher mutagenicity than those from Taihu Lake-based Waterworks A (P＜0.001) and Waterworks B (P = 0.026). Water treatment enhanced the direct mutagenicity (P = 0.022), and weakened the estrogenicity of the raw water (P＜0.001) with a median removal rate of 100%. In fact, very few of the finished samples showed estrogenic activity. Raw water samples from Waterworks A showed weaker estrogenicity than those from Waterworks B (P = 0.034) and Waterworks C (P = 0.006). In summary, mutagenic effects in drinking water and estrogenic effects in raw water merited sustained attention. The Yangtze River was more seriously polluted by mutagenic and estrogenic chemicals than Taihu Lake was. Copyright © 2017 Elsevier Ltd. All rights reserved.

Miscibility at the immiscible liquid/liquid interface: A molecular dynamics study of thermodynamics and mechanism

NASA Astrophysics Data System (ADS)

Karnes, John J.; Benjamin, Ilan

2018-01-01

Molecular dynamics simulations are used to study the dissolution of water into an adjacent, immiscible organic liquid phase. Equilibrium thermodynamic and structural properties are calculated during the transfer of water molecule(s) across the interface using umbrella sampling. The net free energy of transfer agrees reasonably well with experimental solubility values. We find that water molecules "prefer" to transfer into the adjacent phase one-at-a-time, without co-transfer of the hydration shell, as in the case of evaporation. To study the dynamics and mechanism of transfer of water to liquid nitrobenzene, we collected over 400 independent dissolution events. Analysis of these trajectories suggests that the transfer of water is facilitated by interfacial protrusions of the water phase into the organic phase, where one water molecule at the tip of the protrusion enters the organic phase by the breakup of a single hydrogen bond.

Seafloor horizontal positioning from a continuously operating buoy-based GPS-acoustic array

NASA Astrophysics Data System (ADS)

Chadwell, C. D.; Brown, K. M.; Tryon, M. D.; Send, U.

2009-12-01

Seafloor horizontal positions in a global frame were estimated daily from an autonomous buoy operating continuously over several months. The buoy (GEOCE) was moored offshore San Diego in 100-m-deep waters above an array of 4 seafloor transponders. Dual-frequency GPS data were collected at 1-Hz at a main antenna on the buoy and at 3 shore stations to provide continuous 2-3 cm positions of the buoy main antenna. Two single-frequency antennas on the buoy along with the main antenna were used to estimate the buoy attitude and short-term velocity. At one minute intervals the two-way acoustic travel time was measured between the buoy and transponders. During this few second span when transmitting and receiving acoustic signals, 10-Hz attitude and velocity were collected to locate the position of the transducer mounted approximately 2 m below the water line. The GPS and acoustic data were recorded internally and transmitted to shore over a cell-phone link and/or a wireless Ethernet. GPS data were combined with the acoustic data to estimate the array location at 1 minute intervals. The 1-minute positions are combined to provide a daily estimate of the array position. The buoy is autonomous, solar-powered and in addition to the GPS and acoustic data collects air pressure, temperature, wind speed/direction as well as water level at the surface and conductivity and temperature along the mooring line from near the sea surface to just above the sea floor. Here we report results from the horizontal positioning effort from Phase I of the project in shallow waters. The project also includes a vertical deformation sensor and physical oceanographic monitoring. A deep water (nominally 1000 m) test is planned for 2010. This work is supported by NSF-OCE-0551363 of the Ocean Technology and Interdisciplinary Coordination Program.

Hydrophobin-nanofibrillated cellulose stabilized emulsions for encapsulation and release of BCS class II drugs.

PubMed

Paukkonen, Heli; Ukkonen, Anni; Szilvay, Geza; Yliperttula, Marjo; Laaksonen, Timo

2017-03-30

The purpose of this study was to construct biopolymer-based oil-in-water emulsion formulations for encapsulation and release of poorly water soluble model compounds naproxen and ibuprofen. Class II hydrophobin protein HFBII from Trichoderma reesei was used as a surfactant to stabilize the oil/water interfaces of the emulsion droplets in the continuous aqueous phase. Nanofibrillated cellulose (NFC) was used as a viscosity modifier to further stabilize the emulsions and encapsulate protein coated oil droplets in NFC fiber network. The potential of both native and oxidized NFC were studied for this purpose. Various emulsion formulations were prepared and the abilities of different formulations to control the drug release rate of naproxen and ibuprofen, used as model compounds, were evaluated. The optimal formulation for sustained drug release consisted of 0.01% of drug, 0.1% HFBII, 0.15% oxidized NFC, 10% soybean oil and 90% water phase. By comparison, the use of native NFC in combination with HFBII resulted in an immediate drug release for both of the compounds. The results indicate that these NFC originated biopolymers are suitable for pharmaceutical emulsion formulations. The native and oxidized NFC grades can be used as emulsion stabilizers in sustained and immediate drug release applications. Furthermore, stabilization of the emulsions was achieved with low concentrations of both HFBII and NFC, which may be an advantage when compared to surfactant concentrations of conventional excipients traditionally used in pharmaceutical emulsion formulations. Copyright © 2017 Elsevier B.V. All rights reserved.

Reverse micelle-mediated dispersive liquid-liquid microextraction of 2,4-dichlorophenoxyacetic acid and 4-chloro-2-methylphenoxyacetic acid.

PubMed

Tayyebi, Moslem; Yamini, Yadollah; Moradi, Morteza

2012-09-01

A supramolecular solvent consisting of reverse micelles of decanoic acid, dispersed in a continuous phase of tetrahydrofuran:water, was proposed as an efficient microextraction technique for extraction of selected chlorophenoxy acid herbicides from water samples prior to high-performance liquid chromatography UV determination. The disperser solvent (1.0 mL tetrahydrofuran) containing 20 mg decanoic acid was rapidly injected into 10.0 mL of water sample. After centrifugation, the reverse micelle-rich phase (25 ± 0.5 μL) was floated at top of the home-designed centrifuge tube. The solvent was collected and 20 μL of it was injected into high-performance liquid chromatography for analysis. The results showed that the in situ solvent formation and extraction process can be completed in a few seconds. Under the optimal conditions, limits of detection of the method for 4-chloro-2-methylphenoxyacetic acid and 2,4-dichlorophenoxyacetic acid were in the range of 0.5-0.8 μg L(-1) and the repeatability of the proposed method, expressed as relative standard deviation, varied in the range of 2.5-3.2%. Linearity was found to be in the range of 1-200 μg L(-1) and the preconcentration factors were between 148 and 157. The mean percentage recoveries exceeded 92.0% for all the spiking levels in real water samples. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Dysrhythmia of timed movements in Parkinson's disease and freezing of gait.

PubMed

Tolleson, Christopher M; Dobolyi, David G; Roman, Olivia C; Kanoff, Kristen; Barton, Scott; Wylie, Scott A; Kubovy, Michael; Claassen, Daniel O

2015-10-22

A well-established motor timing paradigm, the Synchronization-Continuation Task (SCT), quantifies how accurately participants can time finger tapping to a rhythmic auditory beat (synchronization phase) then maintain this rhythm after the external auditory cue is extinguished, where performance depends on an internal representation of the beat (continuation phase). In this study, we investigated the hypothesis that Parkinson's disease (PD) patients with clinical symptoms of freezing of gait (FOG) exhibit exaggerated motor timing deficits. We predicted that dysrhythmia is exacerbated when finger tapping is stopped temporarily and then reinitiated under the guidance of an internal representation of the beat. Healthy controls and PD patients with and without FOG performed the SCT with and without the insertion of a 7-s cessation of motor tapping between synchronization and continuation phases. With no interruption between synchronization and continuation phases, PD patients, especially those with FOG, showed pronounced motor timing hastening at the slowest inter-stimulus intervals during the continuation phase. The introduction of a gap prior to the continuation phase had a beneficial effect for healthy controls and PD patients without FOG, although patients with FOG continued to show pronounced and persistent motor timing hastening. Ratings of freezing of gait severity across the entire sample of PD tracked closely with the magnitude of hastening during the continuation phase. These results suggest that PD is accompanied by a unique dysrhythmia of measured movements, with FOG reflecting a particularly pronounced disruption to internal rhythmic timing. Copyright © 2015 Elsevier B.V. All rights reserved.

More is the Same; Phase Transitions and Mean Field Theories

NASA Astrophysics Data System (ADS)

Kadanoff, Leo P.

2009-12-01

This paper is the first in a series that will look at the theory of phase transitions from the perspectives of physics and the philosophy of science. The series will consider a group of related concepts derived from condensed matter and statistical physics. The key technical ideas go under the names of "singularity", "order parameter", "mean field theory", "variational method", "correlation length", "universality class", "scale changes", and "renormalization". The first four of these will be considered here. In a less technical vein, the question here is how can matter, ordinary matter, support a diversity of forms. We see this diversity each time we observe ice in contact with liquid water or see water vapor (steam) come up from a pot of heated water. Different phases can be qualitatively different in that walking on ice is well within human capacity, but walking on liquid water is proverbially forbidden to ordinary humans. These differences have been apparent to humankind for millennia, but only brought within the domain of scientific understanding since the 1880s. A phase transition is a change from one behavior to another. A first order phase transition involves a discontinuous jump in some statistical variable. The discontinuous property is called the order parameter. Each phase transition has its own order parameter. The possible order parameters range over a tremendous variety of physical properties. These properties include the density of a liquid-gas transition, the magnetization in a ferromagnet, the size of a connected cluster in a percolation transition, and a condensate wave function in a superfluid or superconductor. A continuous transition occurs when the discontinuity in the jump approaches zero. This article is about statistical mechanics and the development of mean field theory as a basis for a partial understanding of phase transition phenomena. Much of the material in this review was first prepared for the Royal Netherlands Academy of Arts and Sciences in 2006. It has appeared in draft form on the authors' web site (http://jfi.uchicago.edu/~leop/) since then. The title of this article is a hommage to Philip Anderson and his essay "More is Different" (Sci. New Ser. 177(4047):393-396, 1972; N.-P. Ong and R. Bhatt (eds.) More is Different: Fifty Years of Condensed Matter Physics, Princeton Series in Physics, Princeton University Press, 2001) which describes how new concepts, not applicable in ordinary classical or quantum mechanics, can arise from the consideration of aggregates of large numbers of particles. Since phase transitions only occur in systems with an infinite number of degrees of freedom, such transitions are a prime example of Anderson's thesis.

Stem Cell Therapy to Improve Burn Wound Healing

DTIC Science & Technology

2017-03-01

Aim(s) • Perform Phase 1 Trial of Allogeneic MSCs in Burns • Perform Phase 2 Trial of Allogeneic MSCs in Burns • Collect Tissue Repository for...for safety/dose studies CY15 Goal – Continue Phase 1 and, Start Tissue Repository  Continue donors recruitment, screening and Bone Marrow Aspiration...1 Trial and Collect Tissue Repository  Continue donors recruitment, screening and Bone Marrow Aspiration as needed.  Continue patients screening

Fast, multi-phase H2O measurements on board of HALO: Results from the novel HAI instrument during the first field campaigns.

NASA Astrophysics Data System (ADS)

Buchholz, Bernhard; Afchine, Armin; Krämer, Martina; Ebert, Volker

2014-05-01

Water vapor is a key species for many questions in atmospheric research [1] [2] but is also a gas species which is complex to handle. A particular challenge is the simultaneous quantification of gas and condensed phase water. This is especially true for measurements on airborne platforms but also for laboratory experiments [3]. On research aircraft, total water measurement (i.e. the sum of gas-phase and ice-phase) is realized by sampling air with an inlet faced into flight direction ('forward' sampling) and subsequent evaporation of the ice crystals in the heated sampling lines. Gas-phase detection is typically realized using inlets facing against flight direction ('backward' sampling) or 'Rosemount' inlets where an air stream is sampled perpendicular to the high speed airflow through the inlet. For both methods it is believed that no ice crystals reach the downstream hygrometer, but the question remains - especially for Rosemount inlets - if some small ice particles or water droplets may have entered the sampling lines. In addition to the question of proper sampling of the water phases, currently no hygrometer exists that measures all phases with the same measurement principle in one instrument. In the rare occasions that multi-phase measurements are realized, gas-and condensed-phase observations rely on different methods and calibration strategies so that precision and accuracy levels are difficult to compare. The novel HAI (Hygrometer for Atmospheric Investigation) realizes a simultaneous multi-phase hygrometer in a unique concept [4]. Water detection with HAI is based on Tunable Diode Laser Absorption Spectroscopy (TDLAS) with a special evaluation method allowing absolute water vapor measurements without any sensor calibration [5]. The HAI instrument contains two independent dual-channel spectrometers, one at 1.4 μm and one at 2.6 μm which allows to cover a very wide water concentration range from 1 to 30 000 ppmv. Both HAI spectrometers couple one light path in a so called "closed-path" cell [6] for total water measurement via a forward facing inlet. The other part of the laser light is coupled to an "open-path" cell [7] placed outside of the aircraft fuselage to measure gas phase water without any possible artifacts from ice or liquid particles. The frequency of the measurements can be up to 240 Hz (4.2 msec) for all four channels. Altogether, the novel HAI instrument allows fast, accurate and precise dual-phase water measurements. The individual evaluation of the multi-channel raw-data is done afterwards, without any channel interdependencies, in a calibration-free mode. The water signals are combined with an extensive set of more than 100 housekeeping data to enable a holistic data quality management and a rigorous signal scrutiny to maximize the confidence level of the final H2O values. HAI therefore represents a new unique research tool for atmospheric hygrometry to address numerous open topics in atmospheric research. First scientific HAI campaigns have been successfully realized in 2012 onboard the German research plane HALO (High Altitude and Long Range Research Aircraft) during the TACTS and ESMVal missions. The first two HALO campaigns in clouds (MLCIRRUS and ACRIDICON) will be realized in 2014. In our contribution we present and discuss the performance of HAI and show detailed evaluations of typical inflight data. The results of the first two HAI campaigns on HALO resulted in more than 100 operation hours of continuous data and show nice agreement between the closed-path and open-path under clear sky conditions, despite the different sampling conditions of the sensor channels and airspeed of up to 900 km/h in the open path section. All mission data are and will be uploaded to the HALO database and are available for further scientific exploitation. Furthermore, the HAI principle can be adapted to other (airborne) platforms and be used for phase resolved science of the atmospheric water cycle. In parallel HAI's cal-free data evaluation principle will be validated with metrological scrutiny to further investigate the possibility of flying field-qualified metrological transfer standards to resolve the persistent discrepancies in atmospheric hygrometry. The HAI development is funded by DFG within the SPP 1294 HALO via FKZ EB 235/3 [1] A. R. Ravishankara, Science, vol. 337, no. 6096, pp. 809-810, (2012), doi:10.1126/science.1227004. [2] S. Sherwood, S. Bony, and J. Dufresne, Nature, vol. 505, no. 7481, pp. 37-42, (2014), [3] D. Fahey R. Gao, 'Summary of the AquaVIT Water Vapor Intercomparison' source: https://aquavit.icg.kfa-juelich.de/WhitePaper/AquaVITWhitePaper_Final_23Oct2009_6MB.pdf, (2009). [4] V. Ebert, C. Lauer, H. Saathoff, S. Hunsmann, and S. Wagner, Geophys. Res.Abstr., 10, p. EGU2008-A-10066 (2008). [5] V. Ebert and J. Wolfrum, 'Absorption spectroscopy,' in Optical Measurements - Techniques and Applications, F. Mayinger and O. Feldmann, Eds., Springer Heidelberg, München, ISBN:978-3540666905, pp. 273-312, (2000). [6] B. Buchholz, B. Kühnreich, HGJ. Smit, V. Ebert, Appl. Phys. B, vol. 110, no. 2, pp. 249-262, (2013), [7] B. Buchholz, A. Afchine, A. Klein, J. Barthel, T. Klostermann, S. Kallweit, M. Krämer, C. Schiller, and V. Ebert, in DGAO Proceedings, ISSN:1614-8436 - urn:nbn:de:0287-2013-B035-5, (2013).

The Backscatter Cloudprobe with Polarization Detection: A New Aircraft Ice Water Detector

NASA Astrophysics Data System (ADS)

Freer, M.; Baumgardner, D.; Axisa, D.

2017-12-01

The differentiation of liquid water and ice crystals smaller than 100 um in mixed phase clouds continues to challenge the cloud measurement community. In situ imaging probes now have pixel resolution down to about 5 um, but at least 10 pixels are needed to accurately distinguish a water droplet from an ice crystal. This presents a major obstacle for the understanding of cloud glaciation in general, and the formation and evolution of cloud ice in particular. A new sensor has recently been developed that can detect and quantify supercooled liquid droplets and ice crystals. The Backscatter Cloudprobe with Polarization Detection (BCPD) is a very lightweight, compact and low power optical spectrometer that has already undergone laboratory, wind tunnel and flight tests that have validated its capabilities. The BCPD employs the optical approach with single particles that has been used for years in remote sensing to distinguish liquid water from ice crystals in ensembles of cloud particles. The sensor is mounted inside an aircraft and projects a linearly polarized laser beam to the outside through a heated window. Particles that pass through the sample volume of the laser scatter light and the photons scattered in the back direction pass through another heated window where they are collected and focused onto a beam splitter that directs them onto two photodetectors. The P-detector senses the light with polarization parallel to that of the incident light and the S-Detector measures the light that is perpendicular to that of the laser. The polarization ratio, S/P, is sensitive to the asphericity of a particle and is used to identify liquid water and ice crystals. The BCPD has now been exercised in an icing wind tunnel where it was compared with other cloud spectrometers. It has also been flown on the NCAR C-130 and on a commercial Citation, making measurements in all water, all ice and mixed phase clouds. Results from these three applications clearly show that the BCPD can be employed successfully to derive ice fraction in mixed phase clouds at sizes less than 50 um, a size range that has previously been inaccessible to cloud researchers.

Uniform discotic wax particles via electrospray emulsification.

PubMed

Mejia, Andres F; He, Peng; Luo, Dawei; Marquez, Manuel; Cheng, Zhengdong

2009-06-01

We present a novel colloidal discotic system: the formation and self-assembling of wax microdisks with a narrow size distribution. Uniform wax emulsions are first fabricated by electrospraying of melt alpha-eicosene. The size of the emulsions can be flexibly tailored by varying the flow rate of the discontinuous phase, its electric conductivity, and the applied voltage. The process of entrainment of wax droplets, vital for obtaining uniform emulsions, is facilitated by the reduction of air-water surface tension and the density of the continuous phase. Then uniform wax discotic particles are produced via phase transition, during which the formation of a layered structure of the rotator phase of wax converts the droplets, one by one, into oblate particles. The time span for the conversion from spherical emulsions to disk particles is linearly dependent on the size of droplets in the emulsion, indicating the growth of a rotator phase from surface to the center is the limiting step in the shape transition. Using polarized light microscopy, the self-assembling of wax disks is observed by increasing disk concentration and inducing depletion attraction among disks, where several phases, such as isotropic, condensed, columnar stacking, and self-assembly of columnar rods are present sequentially during solvent evaporation of a suspension drop.

Water Resources Data, Florida, Water Year 2003, Volume 4. Northwest Florida

USGS Publications Warehouse

prepared by Blum, Darlene A.; Alvarez, A. Ernie

2004-01-01

The U.S. Geological Survey (USGS), in cooperation with Federal, State, and local agencies, obtains a large amount of data on the water resources of the State of Florida each water year. These data, accumulated during many water years, constitute a valuable database that is used by water-resources managers, emergency-management officials, and many others to develop an improved understanding of water resources within the State. This report series for the 2003 water year for the state of Florida consists of records for continuous or daily discharge for 385 streams, periodic discharge for 13 streams, continuous or daily stage for 255 streams, periodic stage for 13 streams, peak stage and discharge for 36 streams, continuous or daily elevations for 13 lakes, periodic elevations for 46 lakes, continuous ground-water levels for 441 wells, periodic ground-water levels for 1,227 wells, and quality-of-water for 133 surface-water sites and 308 wells. This volume (Volume 4, Northwest Florida)contains records of continuous or daily discharge for 72 streams, periodic discharge for 3 stream, continuous or daily stage for 13 streams, periodic stage for 0 stream, peak stage and discharge for 28 streams, continuous or daily elevations for 1 lake, periodic elevations for 0 lakes, continuous ground-water levels for 3 wells, periodic ground-water levels for 0 wells, and quality-of-water for 3 surface-water sites and 0 wells. These data represent the National Water Data System records collected by the U.S. Geological Survey and cooperating local, State, and Federal agencies in Florida.

Continued development of a semianalytical solution for two-phase fluid and heat flow in a porous medium

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

Doughty, C.; Pruess, K.

1991-06-01

Over the past few years the authors have developed a semianalytical solution for transient two-phase water, air, and heat flow in a porous medium surrounding a constant-strength linear heat source, using a similarity variable {eta} = r/{radical}t. Although the similarity transformation approach requires a simplified geometry, all the complex physical mechanisms involved in coupled two-phase fluid and heat flow can be taken into account in a rigorous way, so that the solution may be applied to a variety of problems of current interest. The work was motivated by adverse to predict the thermohydrological response to the proposed geologic repository formore » heat-generating high-level nuclear wastes at Yucca Mountain, Nevada, in a partially saturated, highly fractured volcanic formation. The paper describes thermal and hydrologic conditions near the heat source; new features of the model; vapor pressure lowering; and the effective-continuum representation of a fractured/porous medium.« less

Nanoblinker: Brownian Motion Powered Bio-Nanomachine for FRET Detection of Phagocytic Phase of Apoptosis

PubMed Central

Minchew, Candace L.; Didenko, Vladimir V.

2014-01-01

We describe a new type of bio-nanomachine which runs on thermal noise. The machine is solely powered by the random motion of water molecules in its environment and does not ever require re-fuelling. The construct, which is made of DNA and vaccinia virus topoisomerase protein, can detect DNA damage by employing fluorescence. It uses Brownian motion as a cyclic motor to continually separate and bring together two types of fluorescent hairpins participating in FRET. This bio-molecular oscillator is a fast and specific sensor of 5′OH double-strand DNA breaks present in phagocytic phase of apoptosis. The detection takes 30 s in solution and 3 min in cell suspensions. The phagocytic phase is critical for the effective execution of apoptosis as it ensures complete degradation of the dying cells’ DNA, preventing release of pathological, viral and tumor DNA and self-immunization. The construct can be used as a smart FRET probe in studies of cell death and phagocytosis. PMID:25268504

Green synthesis of isopropyl myristate in novel single phase medium Part II: Packed bed reactor (PBR) studies.

PubMed

Vadgama, Rajeshkumar N; Odaneth, Annamma A; Lali, Arvind M

2015-12-01

Isopropyl myristate is a useful functional molecule responding to the requirements of numerous fields of application in cosmetic, pharmaceutical and food industry. In the present work, lipase-catalyzed production of isopropyl myristate by esterification of myristic acid with isopropyl alcohol (molar ratio of 1:15) in the homogenous reaction medium was performed on a bench-scale packed bed reactors, in order to obtain suitable reaction performance data for upscaling. An immobilized lipase B from Candida antartica was used as the biocatalyst based on our previous study. The process intensification resulted in a clean and green synthesis process comprising a series of packed bed reactors of immobilized enzyme and water dehydrant. In addition, use of the single phase reaction system facilitates efficient recovery of the product with no effluent generated and recyclability of unreacted substrates. The single phase reaction system coupled with a continuous operating bioreactor ensures a stable operational life for the enzyme.

Manipulation of Microenvironment with a Built-in Electrochemical Actuator in Proximity of a Dissolved Oxygen Microsensor

NASA Technical Reports Server (NTRS)

Kim, Chang-Soo; Lee, Cae-Hyang; Fiering, Jason O.; Ufer, Stefan; Scarantino, Charles W.; Nagle, H. Troy; Fiering, Jason O.; Ufer, Stefan; Nagle, H. Troy; Scarantino, Charles W.

2004-01-01

Abstract - Biochemical sensors for continuous monitoring require dependable periodic self- diagnosis with acceptable simplicity to check its functionality during operation. An in situ self- diagnostic technique for a dissolved oxygen microsensor is proposed in an effort to devise an intelligent microsensor system with an integrated electrochemical actuation electrode. With a built- in platinum microelectrode that surrounds the microsensor, two kinds of microenvironments, called the oxygen-saturated or oxygen-depleted phases, can be created by water electrolysis depending on the polarity. The functionality of the microsensor can be checked during these microenvironment phases. The polarographic oxygen microsensor is fabricated on a flexible polyimide substrate (Kapton) and the feasibility of the proposed concept is demonstrated in a physiological solution. The sensor responds properly during the oxygen-generating and oxygen- depleting phases. The use of these microenvironments for in situ self-calibration is discussed to achieve functional integration as well as structural integration of the microsensor system.

Biochar enables anaerobic digestion of aqueous phase from intermediate pyrolysis of biomass.

PubMed

Torri, Cristian; Fabbri, Daniele

2014-11-01

Intermediate pyrolysis produces a two-phase liquid whose aqueous phase is characterized by low heating value and high water content (aqueous pyrolysis liquid, APL). Anaerobic digestion can be the straightest way to produce a fuel (methane) from this material. Batch tests showed poor performance in anaerobic digestion of APL, which underlined the inhibition of biological process. Nutrient supplementation was ineffective, whereas biochar addition increased yield of methane (60±15% of theoretical) with respect to pure APL (34±6% of theoretical) and improved the reaction rate. On the basis of batch results, a semi-continuous biomethanation test was set up, by adding an increasingly amount of APL in a 30ml reactor preloaded with biochar (0.8gml(-1)). With a daily input of 5gd(-1)l(-1) of APL (corresponding to overall amount of 0.1kgl(-1) added before the end of the study) the yield of methane was 65±5% of the theoretical. Copyright © 2014 Elsevier Ltd. All rights reserved.

Water Resources Data, Florida, Water Year 2003, Volume 3B: Southwest Florida Ground Water

USGS Publications Warehouse

Kane, Richard L.; Fletcher, William L.; Lane, Susan L.

2004-01-01

Water resources data for the 2003 water year in Florida consist of continuous or daily discharges for 385 streams, periodic discharge for 13 streams, continuous daily stage for 255 streams, periodic stage for 13 streams, peak stage for 36 streams and peak discharge for 36 streams, continuous or daily elevations for 13 lakes, periodic elevations for 46 lakes; continuous ground-water levels for 441 wells, periodic ground-water levels for 1,227 wells, and quality-of-water data for 133 surface-water sites and 308 wells. The data for Southwest Florida include records of stage, discharge, and water quality of streams; stage, contents, water quality of lakes and reservoirs, and water levels and water quality of ground-water wells. Volume 3B contains records for continuous ground-water elevations for 128 wells; periodic ground-water elevations at 31 wells; miscellaneous ground-water elevations at 405 wells; and water quality at 32 ground-water sites. These data represent the national Water Data System records collected by the U.S. Geological Survey and cooperating local, state, and federal agencies in Florida.

A novel continuous two-phase partitioning bioreactor operated with polymeric tubing: Performance validation for enhanced biological removal of toxic substrates.

PubMed

Tomei, M Concetta; Mosca Angelucci, Domenica; Daugulis, Andrew J

2017-02-01

A continuous two-phase partitioning bioreactor (C-TPPB), operated with coiled tubing made of the DuPont polymer Hytrel 8206, was tested for the bioremediation of 4-chlorophenol, as a model toxic compound. The tubing was immersed in the aqueous phase, with the contaminated water flowing tube-side, and an adapted microbial culture suspended in the bioreactor itself, with the metabolic demand of the cells creating a concentration gradient to cause the substrate to diffuse into the bioreactor for biodegradation. The system was operated over a range of loadings (tubing influent concentration 750-1500 mg L -1 ), with near-complete substrate removal in all cases. Distribution of the contaminant at the end of the tests (96 h) highlighted biological removal in the range of 87-95%, while the amount retained in the polymer ranged from ∼1 to 8%. Mass transfer of the substrate across the tubing wall was not limiting, and the polymer demonstrated the capacity to buffer the substrate loadings and to adapt to microbial metabolism. The impact of C-TPPB operation on biomass activity was also investigated by a kinetic characterization of the microbial culture, which showed better resistance to substrate inhibition after C-TPPB operation, thereby confirming the beneficial effect of sub-inhibitory controlled conditions, characteristic of TPPB systems. Copyright © 2016 Elsevier Ltd. All rights reserved.

Analysis of solar water heater with parabolic dish concentrator and conical absorber

NASA Astrophysics Data System (ADS)

Rajamohan, G.; Kumar, P.; Anwar, M.; Mohanraj, T.

2017-06-01

This research focuses on developing novel technique for a solar water heating system. The novel solar system comprises a parabolic dish concentrator, conical absorber and water heater. In this system, the conical absorber tube directly absorbs solar radiation from the sun and the parabolic dish concentrator reflects the solar radiations towards the conical absorber tube from all directions, therefore both radiations would significantly improve the thermal collector efficiency. The working fluid water is stored at the bottom of the absorber tubes. The absorber tubes get heated and increases the temperature of the working fluid inside of the absorber tube and causes the working fluid to partially evaporate. The partially vaporized working fluid moves in the upward direction due to buoyancy effect and enters the heat exchanger. When fresh water passes through the heat exchanger, temperature of the vapour decreases through heat exchange. This leads to condensation of the vapour and forms liquid phase. The working fluid returns to the bottom of the collector absorber tube by gravity. Hence, this will continue as a cyclic process inside the system. The proposed investigation shows an improvement of collector efficiency, enhanced heat transfer and a quality water heating system.

Household-Level Determinants of Soil and Water Conservation Adoption Phases: Evidence from North-Western Ethiopian Highlands.

PubMed

Teshome, Akalu; de Graaff, Jan; Kassie, Menale

2016-03-01

Soil and water conservation (SWC) practices have been promoted in the highlands of Ethiopia during the last four decades. However, the level of adoption of SWC practices varies greatly. This paper examines the drivers of different stages of adoption of SWC technologies in the north-western highlands of Ethiopia. This study is based on a detailed farm survey among 298 households in three watersheds. Simple descriptive statistics were applied to analyze the stages of adoption. An ordered probit model was used to analyze the drivers of different stages of adoption of SWC. This model is used to analyze more than two outcomes of an ordinal dependent variable. The results indicate that sampled households are found in different phases of adoption, i.e., dis-adoption/non-adoption (18.5 %), initial adoption (30.5 %), actual adoption (20.1 %), and final adoption (30.9 %). The results of the ordered probit model show that some socio-economic and institutional factors affect the adoption phases of SWC differently. Farm labor, parcel size, ownership of tools, training in SWC, presence of SWC program, social capital (e.g., cooperation with adjacent farm owners), labor sharing scheme, and perception of erosion problem have a significant positive influence on actual and final adoption phases of SWC. In addition, the final adoption phase of SWC is positively associated with tenure security, cultivated land sizes, parcel slope, and perception on SWC profitability. Policy makers should take into consideration factors affecting (continued) adoption of SWC such as profitability, tenure security, social capital, technical support, and resource endowments (e.g., tools and labor) when designing and implementing SWC policies and programs.

Household-Level Determinants of Soil and Water Conservation Adoption Phases: Evidence from North-Western Ethiopian Highlands

NASA Astrophysics Data System (ADS)

Teshome, Akalu; de Graaff, Jan; Kassie, Menale

2016-03-01

Soil and water conservation (SWC) practices have been promoted in the highlands of Ethiopia during the last four decades. However, the level of adoption of SWC practices varies greatly. This paper examines the drivers of different stages of adoption of SWC technologies in the north-western highlands of Ethiopia. This study is based on a detailed farm survey among 298 households in three watersheds. Simple descriptive statistics were applied to analyze the stages of adoption. An ordered probit model was used to analyze the drivers of different stages of adoption of SWC. This model is used to analyze more than two outcomes of an ordinal dependent variable. The results indicate that sampled households are found in different phases of adoption, i.e., dis-adoption/non-adoption (18.5 %), initial adoption (30.5 %), actual adoption (20.1 %), and final adoption (30.9 %). The results of the ordered probit model show that some socio-economic and institutional factors affect the adoption phases of SWC differently. Farm labor, parcel size, ownership of tools, training in SWC, presence of SWC program, social capital (e.g., cooperation with adjacent farm owners), labor sharing scheme, and perception of erosion problem have a significant positive influence on actual and final adoption phases of SWC. In addition, the final adoption phase of SWC is positively associated with tenure security, cultivated land sizes, parcel slope, and perception on SWC profitability. Policy makers should take into consideration factors affecting (continued) adoption of SWC such as profitability, tenure security, social capital, technical support, and resource endowments (e.g., tools and labor) when designing and implementing SWC policies and programs.

The phase diagram of water at negative pressures: virtual ices.

PubMed

Conde, M M; Vega, C; Tribello, G A; Slater, B

2009-07-21

The phase diagram of water at negative pressures as obtained from computer simulations for two models of water, TIP4P/2005 and TIP5P is presented. Several solid structures with lower densities than ice Ih, so-called virtual ices, were considered as possible candidates to occupy the negative pressure region of the phase diagram of water. In particular the empty hydrate structures sI, sII, and sH and another, recently proposed, low-density ice structure. The relative stabilities of these structures at 0 K was determined using empirical water potentials and density functional theory calculations. By performing free energy calculations and Gibbs-Duhem integration the phase diagram of TIP4P/2005 was determined at negative pressures. The empty hydrates sII and sH appear to be the stable solid phases of water at negative pressures. The phase boundary between ice Ih and sII clathrate occurs at moderate negative pressures, while at large negative pressures sH becomes the most stable phase. This behavior is in reasonable agreement with what is observed in density functional theory calculations.

Water in the Geosystem: Phase Relationships

ERIC Educational Resources Information Center

Geer, Ira W.

1974-01-01

Examines the hydrologic cycle, the overall flow of water in the geosystem. Reviews the basic phase relationships among water, ice, and water vapor which are integrat parts of the hydrologic cycle. (JR)

Continuation-Phase Cognitive Therapy's Effects on Remission and Recovery from Depression

ERIC Educational Resources Information Center

Vittengl, Jeffrey R.; Clark, Lee Anna; Jarrett, Robin B.

2009-01-01

The authors tested the effects of continuation-phase cognitive therapy (C-CT) on remission and recovery from recurrent major depressive disorder, defined as 6 weeks and 8 months, respectively, of continuously absent or minimal symptoms. Responders to acute-phase cognitive therapy were randomized to 8 months of C-CT (n = 41) or assessment control…

Nature of the seismic crust at the Aegir Ridge: A downward continuation approach

NASA Astrophysics Data System (ADS)

Rai, Abhishek; Breivik, Asbj|rn; Mjelde, Rolf; Hanan, Barry; Ito, Garrett; Sayit, Kaan; Howell, Sam; Vogt, Peter; Pedersen, Rolf-Birger

2013-04-01

The marine seismic data are influenced by variations in the thickness and velocity of the water column which causes fluctuations in the arrival times of seismic phases. Downward continuation of the ocean-bottom seismometer data are used to remove the contributions of the water column by bring the shot and receiver at a common datum such as the seafloor. Additionally, the downward continuation focus the seismic energy and hence improves the resolution. We apply the downward continuation technique to analyze the OBS data collected along the eastern shoulder of the Aegir Ridge. The Aegir Ridge is an extinct spreading ridge in the North-East Atlantic ocean. Its proximity to the active Iceland hot-spot makes it important for understanding the process of hotspot-ridge interaction during the Oligocene. We present results of an OBS experiment, supported by single channel streamer, gravity and magnetic observations. Usable seismic data from 20 OBSs distributed along ~550 km length of the profile reveal the variations in crustal thickness and seismic velocities. Regional magnetic anomalies show a faster spreading rate towards the north and a slower spreading towards the southern end near the Iceland hotspot during the active period of the ridge. However, the observed and the predicted crustal thickness show an opposite trend. We interpret this anti-correlation between the seafloor spreading rate and the crustal thickness as a result of the interaction between the Iceland hotspot and the Aegir Ridge.

Upper Extremity Muscle Activity During In-Phase and Anti-Phase Continuous Pushing Tasks.

PubMed

Gruevski, Kristina M; Hodder, Joanne N; Keir, Peter J

2017-11-01

To determine the effect of anti-phase, in-phase bimanual and unimanual simulated industrial pushing tasks and frequency on upper extremity muscle activity. Research investigating symmetrical (in-phase) and asymmetrical (anti-phase) pushing exertions is limited despite a high prevalence in industry. Fifteen female participants completed five pushing tasks using a dual handle apparatus at three frequencies: 15 cycles per minute (cpm), 30 cpm, and self-selected. Tasks included two bimanual symmetrical pushes (constrained and unconstrained), two bimanual asymmetrical pushes (reciprocating and continuous), and one right unimanual push. Surface electromyography (EMG) from the right anterior, middle, and posterior deltoid (AD, MD, and PD); right and left trapezius (RT and LT); right pectoralis major (PM); and right and left external obliques (REO and LEO) was collected and normalized to maximum voluntary effort. There was a task by frequency interaction in the AD, MD, PD, and RT ( p < .005), where activity in AD, MD, and PD was highest in the continuous task at 15 cpm, but activity was similar across task in 30 cpm and self-selected. Muscle activity coefficient of variation was lowest during continuous task across all frequencies. Continuous, anti-phase pushes and constrained, in-phase pushes had the highest muscle activity demands and the least amount of variability in muscle activity and therefore may present the greatest risk of injury. Anti-phase pushing is known to have a greater cognitive demand, and this study demonstrated that it also has a greater physical demand when performed continuously.

What's the P in PPP?

NASA Astrophysics Data System (ADS)

Heikkila, T.; Lall, U.

2011-12-01

Public, Private, Partnership, Participatory, Polycentric, Poor, Perfect, Purveyor, Planner, Positive, Plural, Practical, Political, Process, Pervasive, Phase, Physical, Passive, Progressive, Paradigm? As the world stands at the crossroads of a water scarcity crisis, many wonder whether the "well developed" central planner paradigm of water resources planning, management, investment and regulation that emerged in the last century has served us well. The negative impacts of centralized projects and their management are routinely decried. Service metrics of publicly managed systems continue to deteriorate as the ability to recover operational and maintenance costs continue to be weak. The political processes that portend to protect the access of the disadvantaged are said to contribute to the poor performance of the systems, especially for the disadvantaged. The institutionalization of "well formed" policies that prove inflexible in an environment where supply, demand and societal goals change calls for adaptive management. Stakeholder driven participatory processes and public private partnerships are touted as potential paradigms for progressive solutions that span the political domain and could help achieve positive water balance recognizing the dimensions of supply and demand at local or regional scales. This talk presents a proposed framework that postulates the prospective roles that different actors could play to provide an effective and practical strategy for securing water resources while promoting active allocation strategies, improving access and reliability while promoting profitability for private operators, including progressive farmers who given their usage patterns can make the most prolific contribution to water security. We label this the many P Paradigm. To develop this framework, we draw initial insights from the literature on participatory and decentralized watershed governance. We then apply findings from field experiments on water management reforms in India and Brazil to extend this literature and demonstrate the benefits of the framework to scholars and practitioners alike.

Detailed validation of the bidirectional effect in various Case I and Case II waters.

PubMed

Gleason, Arthur C R; Voss, Kenneth J; Gordon, Howard R; Twardowski, Michael; Sullivan, James; Trees, Charles; Weidemann, Alan; Berthon, Jean-François; Clark, Dennis; Lee, Zhong-Ping

2012-03-26

Simulated bidirectional reflectance distribution functions (BRDF) were compared with measurements made just beneath the water's surface. In Case I water, the set of simulations that varied the particle scattering phase function depending on chlorophyll concentration agreed more closely with the data than other models. In Case II water, however, the simulations using fixed phase functions agreed well with the data and were nearly indistinguishable from each other, on average. The results suggest that BRDF corrections in Case II water are feasible using single, average, particle scattering phase functions, but that the existing approach using variable particle scattering phase functions is still warranted in Case I water.

Nationwide reconnaissance of contaminants of emerging concern in source and treated drinking waters of the United States: Pharmaceuticals.

PubMed

Furlong, Edward T; Batt, Angela L; Glassmeyer, Susan T; Noriega, Mary C; Kolpin, Dana W; Mash, Heath; Schenck, Kathleen M

2017-02-01

Mobile and persistent chemicals that are present in urban wastewater, such as pharmaceuticals, may survive on-site or municipal wastewater treatment and post-discharge environmental processes. These pharmaceuticals have the potential to reach surface and groundwaters, essential drinking-water sources. A joint, two-phase U.S. Geological Survey-U.S. Environmental Protection Agency study examined source and treated waters from 25 drinking-water treatment plants from across the United States. Treatment plants that had probable wastewater inputs to their source waters were selected to assess the prevalence of pharmaceuticals in such source waters, and to identify which pharmaceuticals persist through drinking-water treatment. All samples were analyzed for 24 pharmaceuticals in Phase I and for 118 in Phase II. In Phase I, 11 pharmaceuticals were detected in all source-water samples, with a maximum of nine pharmaceuticals detected in any one sample. The median number of pharmaceuticals for all 25 samples was five. Quantifiable pharmaceutical detections were fewer, with a maximum of five pharmaceuticals in any one sample and a median for all samples of two. In Phase II, 47 different pharmaceuticals were detected in all source-water samples, with a maximum of 41 pharmaceuticals detected in any one sample. The median number of pharmaceuticals for all 25 samples was eight. For 37 quantifiable pharmaceuticals in Phase II, median concentrations in source water were below 113ng/L. For both Phase I and Phase II campaigns, substantially fewer pharmaceuticals were detected in treated water samples than in corresponding source-water samples. Seven different pharmaceuticals were detected in all Phase I treated water samples, with a maximum of four detections in any one sample and a median of two pharmaceuticals for all samples. In Phase II a total of 26 different pharmaceuticals were detected in all treated water samples, with a maximum of 20 pharmaceuticals detected in any one sample and a median of 2 pharmaceuticals detected for all 25 samples. Source-water type influences the presence of pharmaceuticals in source and treated water. Treatment processes appear effective in reducing concentrations of most pharmaceuticals. Pharmaceuticals more consistently persisting through treatment include carbamazepine, bupropion, cotinine, metoprolol, and lithium. Pharmaceutical concentrations and compositions from this study provide an important base data set for further sublethal, long-term exposure assessments, and for understanding potential effects of these and other contaminants of emerging concern upon human and ecosystem health. Copyright © 2016. Published by Elsevier B.V.

New definition of Regulated Deficit Irrigation phases in pistachio: more sustainable, more efficient

NASA Astrophysics Data System (ADS)

Pérez-López, David; Moreno, Marta M.; Memmi, Houssem; Guerrero, Julián; Galindo, Alejandro; Centeno, Ana; Corell, Mireilla; Giron, Ignacio; José Martín-Palomo, María; Gijón, Mª Carmen; Moreno, Carmen; Torrecillas, Arturo; Moriana, Alfonso

2017-04-01

Regulated Deficit Irrigation (RDI) is an irrigation methodology in which a water stress is imposed by irrigation withholding in function of fruit growth phases. The objective of this method is to found phases where water stress has no effect on yield or only a slight effect. RDI in pistachio has been demonstrated as an efficient tool to save water without negative effect on yield, or even the contrary, a slight water stress has produced pistachios more appreciated by consumers opposite to well irrigated. Phases of fruit growth are widely defined as: Phase I, from leaf out to full shell expansion; Phase II, from full shell expansion to the onset of rapid kernel growth; Phase III, from rapid growth to harvest. Water stress applied in Phase II does not affect yield. Traditionally Phase II had been considered interchangeable with shell hardening; however, recent studies have showed that shell hardening extends for two weeks from the beginning of the kernel growth. In this assay, conducted in Ciudad Real (Spain) in 2015 and 2016, different irrigation treatments were applied on a pistachio crop in order to check if shell hardening can be considered as phase II instead the previous definition. The T1 treatment consisted of water stress during the shell hardening, always trying to maintain a stem water potential (SWP) of -1.5 MPa during this phase. The T2 treatment was severely water stressed, in this case trying to maintain -2 MPa during the phase II, as previous definition. In the rest of the season, both treatments were irrigated in order to have no water stress. Additionally, a control treatment (T0), irrigated following FAO methodology, was stablished to evaluate the loss of yield. Water irrigation applied in T0 was 596 and 505 mm in 2015 and 2016, respectively. In T1, 317 and 245 mm were applied, respectively, which means an average water save about 270 mm year-1. In T2, water irrigation was 396 and 272 mm, respectively, higher amounts than in T1, which an average water save of 217 mm year-1. In relation to the minimum SWP measured in the different treatments in 2015 and 2016, T0 reached -1.53 and -1.39 MPa, T1 -1.89 and -1.82 MPa, and T2 -2.26 and -2.21 MPa, respectively. There were not significant differences among yield treatments, neither when considering each year independently or over the entire period of study. In this sense, cumulative yields from the two years were 61, 57 and 68 kg tree-1 in T0, T1 and T2 respectively. Therefore, a new definition of Phase II allows the same yield with a higher water save than when applying an intense water stress during the previous definition.

Final report on Weeks Island Monitoring Phase : 1999 through 2004.

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

Ehgartner, Brian L.; Munson, Darrell Eugene

2005-05-01

This Final Report on the Monitoring Phase of the former Weeks Island Strategic Petroleum Reserve crude oil storage facility details the results of five years of monitoring of various surface accessible quantities at the decommissioned facility. The Weeks Island mine was authorized by the State of Louisiana as a Strategic Petroleum Reserve oil storage facility from 1979 until decommissioning of the facility in 1999. Discovery of a sinkhole over the facility in 1992 with freshwater inflow to the facility threatened the integrity of the oil storage and led to the decision to remove the oil, fill the chambers with brine,more » and decommission the facility. Thereafter, a monitoring phase, by agreement between the Department of Energy and the State, addressed facility stability and environmental concerns. Monitoring of the surface ground water and the brine of the underground chambers from the East Fill Hole produced no evidence of hydrocarbon contamination, which suggests that any unrecovered oil remaining in the underground chambers has been contained. Ever diminishing progression of the initial major sinkhole, and a subsequent minor sinkhole, with time was verification of the response of sinkholes to filling of the facility with brine. Brine filling of the facility ostensively eliminates any further growth or new formation from freshwater inflow. Continued monitoring of sinkhole response, together with continued surface surveillance for environmental problems, confirmed the intended results of brine pressurization. Surface subsidence measurements over the mine continued throughout the monitoring phase. And finally, the outward flow of brine was monitored as a measure of the creep closure of the mine chambers. Results of each of these monitoring activities are presented, with their correlation toward assuring the stability and environmental security of the decommissioned facility. The results suggest that the decommissioning was successful and no contamination of the surface environment by crude oil has been found.« less

Theory of Ostwald ripening in a two-component system

NASA Technical Reports Server (NTRS)

Baird, J. K.; Lee, L. K.; Frazier, D. O.; Naumann, R. J.

1986-01-01

When a two-component system is cooled below the minimum temperature for its stability, it separates into two or more immiscible phases. The initial nucleation produces grains (if solid) or droplets (if liquid) of one of the phases dispersed in the other. The dynamics by which these nuclei proceed toward equilibrium is called Ostwald ripening. The dynamics of growth of the droplets depends upon the following factors: (1) The solubility of the droplet depends upon its radius and the interfacial energy between it and the surrounding (continuous) phase. There is a critical radius determined by the supersaturation in the continuous phase. Droplets with radii smaller than critical dissolve, while droplets with radii larger grow. (2) The droplets concentrate one component and reject the other. The rate at which this occurs is assumed to be determined by the interdiffusion of the two components in the continuous phase. (3) The Ostwald ripening is constrained by conservation of mass; e.g., the amount of materials in the droplet phase plus the remaining supersaturation in the continuous phase must equal the supersaturation available at the start. (4) There is a distribution of droplet sizes associated with a mean droplet radius, which grows continuously with time. This distribution function satisfies a continuity equation, which is solved asymptotically by a similarity transformation method.

Large-Flow-Area Flow-Selective Liquid/Gas Separator

NASA Technical Reports Server (NTRS)

Vasquez, Arturo; Bradley, Karla F.

2010-01-01

This liquid/gas separator provides the basis for a first stage of a fuel cell product water/oxygen gas phase separator. It can separate liquid and gas in bulk in multiple gravity environments. The system separates fuel cell product water entrained with circulating oxygen gas from the outlet of a fuel cell stack before allowing the gas to return to the fuel cell stack inlet. Additional makeup oxygen gas is added either before or after the separator to account for the gas consumed in the fuel cell power plant. A large volume is provided upstream of porous material in the separator to allow for the collection of water that does not exit the separator with the outgoing oxygen gas. The water then can be removed as it continues to collect, so that the accumulation of water does not impede the separating action of the device. The system is designed with a series of tubes of the porous material configured into a shell-and-tube heat exchanger configuration. The two-phase fluid stream to be separated enters the shell-side portion of the device. Gas flows to the center passages of the tubes through the porous material and is then routed to a common volume at the end of the tubes by simple pressure difference from a pumping device. Gas flows through the porous material of the tubes with greater ease as a function of the ratio of the dynamic viscosity of the water and gas. By careful selection of the dimensions of the tubes (wall thickness, porosity, diameter, length of the tubes, number of the tubes, and tube-to-tube spacing in the shell volume) a suitable design can be made to match the magnitude of water and gas flow, developed pressures from the oxygen reactant pumping device, and required residual water inventory for the shellside volume.

Effect of water phase transition on dynamic ruptures with thermal pressurization: Numerical simulations with changes in physical properties of water

NASA Astrophysics Data System (ADS)

Urata, Yumi; Kuge, Keiko; Kase, Yuko

2015-02-01

Phase transitions of pore water have never been considered in dynamic rupture simulations with thermal pressurization (TP), although they may control TP. From numerical simulations of dynamic rupture propagation including TP, in the absence of any water phase transition process, we predict that frictional heating and TP are likely to change liquid pore water into supercritical water for a strike-slip fault under depth-dependent stress. This phase transition causes changes of a few orders of magnitude in viscosity, compressibility, and thermal expansion among physical properties of water, thus affecting the diffusion of pore pressure. Accordingly, we perform numerical simulations of dynamic ruptures with TP, considering physical properties that vary with the pressure and temperature of pore water on a fault. To observe the effects of the phase transition, we assume uniform initial stress and no fault-normal variations in fluid density and viscosity. The results suggest that the varying physical properties decrease the total slip in cases with high stress at depth and small shear zone thickness. When fault-normal variations in fluid density and viscosity are included in the diffusion equation, they activate TP much earlier than the phase transition. As a consequence, the total slip becomes greater than that in the case with constant physical properties, eradicating the phase transition effect. Varying physical properties do not affect the rupture velocity, irrespective of the fault-normal variations. Thus, the phase transition of pore water has little effect on dynamic ruptures. Fault-normal variations in fluid density and viscosity may play a more significant role.

Formation and Evolution of Target Patterns in Cahn-Hilliard Flows: An Extension of the Flux Expulsion Studies in MHD

NASA Astrophysics Data System (ADS)

Fan, Xiang; P H Diamond Collaboration; Luis Chacon Collaboration

2017-10-01

Spinodal decomposition is a second order phase transition for a binary liquid mixture to evolve from a miscible phase (e.g., water + alcohol) to two co-existing phases (e.g., water + oil). The Cahn-Hilliard model for spinodal decomposition is analogous to 2D MHD. We study the evolution of the concentration field in a single eddy in the 2D Cahn-Hilliard system to better understand scalar mixing processes in that system. This study extends investigations of the classic studies of flux expulsion in 2D MHD and homogenization of potential vorticity in 2D fluids. Simulation results show that there are three stages in the evolution: (A) formation of a ``jelly roll'' pattern, for which the concentration field is constant along spirals; (B) a change in isoconcentration contour topology; and (C) formation of a target pattern, for which the isoconcentration contours follow concentric annuli. In the final target pattern stage, the isoconcentration bands align with stream lines. The results indicate that the target pattern is a metastable state. Band merger process continues on a time scale exponentially long relative to the eddy turnover time. The band merger process resembles step merger in drift-ZF staircases. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Fusion Energy Sciences, under Award Number DE-FG02-04ER54738.

Kimberlite ascent by assimilation-fuelled buoyancy.

PubMed

Russell, James K; Porritt, Lucy A; Lavallée, Yan; Dingwell, Donald B

2012-01-18

Kimberlite magmas have the deepest origin of all terrestrial magmas and are exclusively associated with cratons. During ascent, they travel through about 150 kilometres of cratonic mantle lithosphere and entrain seemingly prohibitive loads (more than 25 per cent by volume) of mantle-derived xenoliths and xenocrysts (including diamond). Kimberlite magmas also reputedly have higher ascent rates than other xenolith-bearing magmas. Exsolution of dissolved volatiles (carbon dioxide and water) is thought to be essential to provide sufficient buoyancy for the rapid ascent of these dense, crystal-rich magmas. The cause and nature of such exsolution, however, remains elusive and is rarely specified. Here we use a series of high-temperature experiments to demonstrate a mechanism for the spontaneous, efficient and continuous production of this volatile phase. This mechanism requires parental melts of kimberlite to originate as carbonatite-like melts. In transit through the mantle lithosphere, these silica-undersaturated melts assimilate mantle minerals, especially orthopyroxene, driving the melt to more silicic compositions, and causing a marked drop in carbon dioxide solubility. The solubility drop manifests itself immediately in a continuous and vigorous exsolution of a fluid phase, thereby reducing magma density, increasing buoyancy, and driving the rapid and accelerating ascent of the increasingly kimberlitic magma. Our model provides an explanation for continuous ascent of magmas laden with high volumes of dense mantle cargo, an explanation for the chemical diversity of kimberlite, and a connection between kimberlites and cratons.

Osmotic membrane bioreactor for phenol biodegradation under continuous operation.

PubMed

Praveen, Prashant; Loh, Kai-Chee

2016-03-15

Continuous phenol biodegradation was accomplished in a two-phase partitioning osmotic membrane bioreactor (TPPOMBR) system, using extractant impregnated membranes (EIM) as the partitioning phase. The EIMs alleviated substrate inhibition during prolonged operation at influent phenol concentrations of 600-2000mg/L, and also at spiked concentrations of 2500mg/L phenol restricted to 2 days. Filtration of the effluent through forward osmosis maintained high biomass concentration in the bioreactor and improved effluent quality. Steady state was reached in 5-6 days at removal rates varying between 2000 and 5500mg/L-day under various conditions. Due to biofouling and salt accumulation, the permeate flux varied from 1.2-7.2 LMH during 54 days of operation, while maintaining an average hydraulic retention time of 7.4h. A washing cycle, comprising 1h osmotic backwashing using 0.5M NaCl and 2h washing with water, facilitated biofilm removal from the membranes. Characterization of the extracellular polymeric substances (EPS) through FTIR showed peaks between 1700 and 1500cm(-1), 1450-1450cm(-1) and 1200-1000cm(-1), indicating the presence of proteins, phenols and polysaccharides, respectively. The carbohydrate to protein ratio in the EPS was estimated to be 0.3. These results indicate that TPPOMBR can be promising in continuous treatment of phenolic wastewater. Copyright © 2015 Elsevier B.V. All rights reserved.

Influence of palmitoyl pentapeptide and Ceramide III B on the droplet size of nanoemulsion

NASA Astrophysics Data System (ADS)

Sondari, Dewi; Haryono, Agus; Harmami, Sri Budi; Randy, Ahmad

2010-05-01

The influence of the Palmitoyl Pentapeptide (PPp) and Ceramide IIIB (Cm III B) as active ingredients on the droplet size of nano-emulsion was studied using different kinds of oil (avocado oil, sweet almond oil, jojoba oil, mineral oil and squalene). The formation of nano-emulsions were prepared in water mixed non ionic surfactant/oils system using the spontaneous emulsification mechanism. The aqueous solution, which consist of water and Tween® 20 as a hydrophilic surfactant was mixed homogenously. The organic solution, which consist of oil and Span® 80 as a lipophilic surfactant was mixed homogenously in ethanol. Ethanol was used as a water miscible solvent, which can help the formation of nano-emulsion. The oil phase (containing the blend of surfactant Span® 80, ethanol, oil and active ingredient) and the aqueous phase (containing water and Tween® 20) were separately prepared at room temperatures. The oil phase was slowly added into aqueous phase under continuous mechanical agitation (18000 rpm). All samples were subsequently homogenized with Ultra-Turrax for 30 minutes. The characterizations of nano-emulsion were carried out using photo-microscope and particle size analyzer. Addition of active ingredients on the formation of nano-emulsion gave smallest droplet size compared without active ingredients addition on the formation of nano-emulsion. Squalene oil with Palmitoyl Pentapeptide (PPm) and Ceramide IIIB (Cm IIIB) gave smallest droplet size (184.0 nm) compared without Palmitoyl Pentapeptide and Ceramide IIIB (214.9 nm), however the droplets size of the emulsion prepared by the other oils still in the range of nano-emulsion (below 500 nm). The stability of nano-emulsion was observed using two methods. In one method, the stability of nano-emulsion was observed for three months at temperature of 5°C and 50°C, while in the other method, the stability nano-emulsion was observed by centrifuged at 12000 rpm for 30 minutes. Nanoemulsion with active ingredient was remained stable even when stored until three months. Coalescence process between the droplets was not occurred significantly and droplet size was still below 500 nm. Over all, the emulsion remained stable, even it was centrifuged at 12000 rpm for 30 minutes.

49 CFR 585.2 - Phase-in reports.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 7 2010-10-01 2010-10-01 false Phase-in reports. 585.2 Section 585.2 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PHASE-IN REPORTING REQUIREMENTS General § 585.2 Phase-in reports. Each report submitted to NHTSA...

Phase transformation of mixed-phase clouds

NASA Astrophysics Data System (ADS)

Korolev, Alexei; Isaac, George

2003-01-01

The glaciation time of a mixed-phase cloud due to the Wegener-Bergeron-Findeisen mechanism is calculated using an adiabatic one-dimensional numerical model for the cases of zero, ascending, descending and oscillating vertical velocities. The characteristic values of the glaciation time are obtained for different concentrations of ice particles and liquid-water content. Steady state is not possible for the ice-water content/total water content ratio in a uniformly vertically moving mixed-phase parcel. The vertical oscillation of a cloud parcel may result in a periodic evaporation and activation of liquid droplets in the presence of ice particles during infinite time. After a certain time, the average ice-water content and liquid-water content reach a steady state. This phenomenon may explain the existence of long-lived mixed-phase stratiform layers. The obtained results are important for understanding the mechanisms of formation and life cycle of mixed-phase clouds.

Molecular modeling of the dissociation of methane hydrate in contact with a silica surface.

PubMed

Bagherzadeh, S Alireza; Englezos, Peter; Alavi, Saman; Ripmeester, John A

2012-03-15

We use constant energy, constant volume (NVE) molecular dynamics simulations to study the dissociation of the fully occupied structure I methane hydrate in a confined geometry between two hydroxylated silica surfaces between 36 and 41 Å apart, at initial temperatures of 283, 293, and 303 K. Simulations of the two-phase hydrate/water system are performed in the presence of silica, with and without a 3 Å thick buffering water layer between the hydrate phase and silica surfaces. Faster decomposition is observed in the presence of silica, where the hydrate phase is prone to decomposition from four surfaces, as compared to only two sides in the case of the hydrate/water simulations. The existence of the water layer between the hydrate phase and the silica surface stabilizes the hydrate phase relative to the case where the hydrate is in direct contact with silica. Hydrates bound between the silica surfaces dissociate layer-by-layer in a shrinking core manner with a curved decomposition front which extends over a 5-8 Å thickness. Labeling water molecules shows that there is exchange of water molecules between the surrounding liquid and intact cages in the methane hydrate phase. In all cases, decomposition of the methane hydrate phase led to the formation of methane nanobubbles in the liquid water phase. © 2012 American Chemical Society

Deciphering the factors influencing the discrepant fate of antibiotic resistance genes in sludge and water phases during municipal wastewater treatment.

PubMed

Zhang, Junya; Yang, Min; Zhong, Hui; Liu, Mengmeng; Sui, Qianwen; Zheng, Libing; Tong, Juan; Wei, Yuansong

2018-06-09

The discrepant fate of antibiotic resistance genes (ARGs) in sludge and water phases was investigated in a municipal wastewater treatment plant, and a lab-scale A 2 O-MBR was operated to provide background value of ARGs. The influencing factors of ARGs including microbial community, co-selection from heavy metals, biomass and horizontal gene transfer were concerned. Results showed that iA 2 O (inversed A 2 O) showed better ARGs reduction, and longer SRT (sludge retention time) increased ARGs relative abundance while reduced the gene copies of ARGs in the effluent, but significantly increased the ARGs in sludge phase. Compared to background value, the most enriched ARG was tetX in water phase, while it was intI1 in sludge phase. There existed higher abundance of multi-resistant bacteria in sludge phase, and microbial community determined the fate of ARGs in both water and sludge phase, while the direct effects from horizontal gene transfer should not be overlooked especially in water phase. Copyright © 2018 Elsevier Ltd. All rights reserved.

Partitioning studies of coal-tar constituents in a two-phase contaminated ground-water system

USGS Publications Warehouse

Rostad, C.E.; Pereira, W.E.; Hult, M.F.

1985-01-01

Organic compounds derived from coal-tar wastes in a contaminated aquifer in St. Louis Park, Minnesota, were identified, and their partition coefficients between the tar phase and aqueous phase were determined and compared with the corresponding n-octanol/water partition coefficients. Coal tar contains numerous polycyclic aromatic compounds, many of which are suspected carcinogens or mutagens. Groundwater contamination by these toxic compounds may pose an environmental health hazard in nearby public water-supply wells. Fluid samples from this aquifer developed two phases upon settling: an upper aqueous phase, and a lower oily-tar phase. After separating the phases, polycyclic aromatic compounds in each phase were isolated using complexation with N-methyl-2-pyrrolidone and identified by fused-silica capillary gas chromatography/mass spectrometry. Thirty-one of the polycyclic aromatic compounds were chosen for further study from four different classes: 12 polycyclic aromatic hydrocarbons, 10 nitrogen heterocycles, 5 sulfur heterocycles, and 4 oxygen heterocycles. Within each compound class, the tar/water partition coefficients of these compounds were reasonably comparable with the respective n-octanol/water partition coefficient.

Fate of five pharmaceuticals under different infiltration conditions for managed aquifer recharge.

PubMed

Silver, Matthew; Selke, Stephanie; Balsaa, Peter; Wefer-Roehl, Annette; Kübeck, Christine; Schüth, Christoph

2018-06-18

Infiltration of treated wastewater (TWW) to recharge depleted aquifers, often referred to as managed aquifer recharge, is a solution to replenish groundwater resources in regions facing water scarcity. We present a mass balance approach to infer the amounts of five pharmaceuticals (carbamazepine, diclofenac, fenoprofen, gemfibrozil, and naproxen) degraded in column experiments based on concentrations of pharmaceuticals in the aqueous and solid (sorbed) phases. Column experiments were conducted under three different conditions: continuous infiltration, wetting and drying cycles, and wetting and drying cycles with elevated concentrations of antibiotics (which may reduce microbially aided degradation of other compounds). A mass balance comparing pharmaceutical mass in the water phase over the 16-month duration of the experiments to mass sorbed to the soil was used to infer the mass of pharmaceuticals degraded. Results show sorption as the main attenuation mechanism for carbamazepine. About half of the mass of diclofenac was degraded with wetting and drying cycles, but no significant degradation was found for continuous infiltration, while 32% of infiltrated mass sorbed. Fenoprofen was degraded in the shallow and aerobic part of the soil, but degradation appeared to cease beyond 27 cm depth. Gemfibrozil attenuated through a combination of degradation and sorption, with slight increases in attenuation with depth from both mechanisms. Naproxen degraded progressively with depth, resulting in attenuation of >90% of the mass. In the column with elevated concentrations of antibiotics, the antibiotics attenuated to about 50% or less of inflow concentrations by 27 cm depth and within this zone, less degradation of the other compounds was observed. Copyright © 2018 Elsevier B.V. All rights reserved.

Phase diagram of supercooled water confined to hydrophilic nanopores

NASA Astrophysics Data System (ADS)

Limmer, David T.; Chandler, David

2012-07-01

We present a phase diagram for water confined to cylindrical silica nanopores in terms of pressure, temperature, and pore radius. The confining cylindrical wall is hydrophilic and disordered, which has a destabilizing effect on ordered water structure. The phase diagram for this class of systems is derived from general arguments, with parameters taken from experimental observations and computer simulations and with assumptions tested by computer simulation. Phase space divides into three regions: a single liquid, a crystal-like solid, and glass. For large pores, radii exceeding 1 nm, water exhibits liquid and crystal-like behaviors, with abrupt crossovers between these regimes. For small pore radii, crystal-like behavior is unstable and water remains amorphous for all non-zero temperatures. At low enough temperatures, these states are glasses. Several experimental results for supercooled water can be understood in terms of the phase diagram we present.

Technology transfer program: Perspective

NASA Technical Reports Server (NTRS)

Toyshov, A. J.

1981-01-01

Most of NASA's technology transfer activities are in the area of land use (development, suitability, and planning); forestry (including wildlife and range and vegetation inventories) agriculture related activities; and water resources. The technology dissemination function is exercised through three regional applications centers which are involved in 91 applications projects within 22 states. In addition there are approximately eight application system verification transfer (ASVT) projects, 21 university applications branches, institutionalized liason activities with public interest groups, and user requirements activities. As the result of budget cuts, the ASVT and user requirements and awareness programs are to be phased out at the end of FY81. The university applications programs are to be phased down and terminated by 1985. NASA will continue to work with the user more in an R & D and an applications development capacity, and not in a national scale or administrative way.

Stepwise Synthesis of Giant Unilamellar Vesicles on a Microfluidic Assembly Line

PubMed Central

2011-01-01

Among the molecular milieu of the cell, the membrane bilayer stands out as a complex and elusive synthetic target. We report a microfluidic assembly line that produces uniform cellular compartments from droplet, lipid, and oil/water interface starting materials. Droplets form in a lipid-containing oil flow and travel to a junction where the confluence of oil and extracellular aqueous media establishes a flow-patterned interface that is both stable and reproducible. A triangular post mediates phase transfer bilayer assembly by deflecting droplets from oil, through the interface, and into the extracellular aqueous phase to yield a continuous stream of unilamellar phospholipid vesicles with uniform and tunable size. The size of the droplet precursor dictates vesicle size, encapsulation of small-molecule cargo is highly efficient, and the single bilayer promotes functional insertion of a bacterial transmembrane pore. PMID:21309555

Coupling between the Dynamics of Water and Surfactants in Lyotropic Liquid Crystals.

PubMed

McDaniel, Jesse G; Yethiraj, Arun

2017-05-18

Bilayers composed of lipid or surfactant molecules are central to biological membranes and lamellar lyotropic liquid crystalline (LLC) phases. Common to these systems are phases that exhibit either ordered or disordered packing of the hydrophobic tails. In this work, we study the impact of surfactant ordering, i.e., disordered L α and ordered L β LLC phases, on the dynamics of water and sodium ions in the lamellar phases of dicarboxylate gemini surfactants. We study the different phases at identical hydration levels by changing the length of the hydrophobic tails; surfactants with shorter tails form L α phases and those with longer tails form L β phases. We find that the L α phases exhibit lower density and greater compressibility than the L β phases, with a hydration-dependent headgroup surface area. These structural differences significantly affect the relative dynamic properties of the phases, primarily the mobility of the surfactant molecules tangential to the bilayer surface, as well as the rates of water and ion diffusion. We find ∼20-50% faster water diffusion in the L α phases compared to the L β phases, with the differences most pronounced at low hydration. This coupling between water dynamics and surfactant mobility is verified using additional simulations in which the surfactant tails are frozen. Our study indicates that gemini surfactant LLCs provide an important prototypical system for characterizing properties shared with more complex biological lipid membranes.

Demulsification of water/oil/solid emulsions by hollow-fiber membranes

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

Tirmizi, N.P.; Raghuraman, B.; Wiencek, J.

1996-05-01

The demulsification techniques investigated use preferential surface wetting to allow separation of oil and water phases in ultrafiltration and microfiltration membranes. A hydrophobic membrane allows the permeation of an oil phase at almost zero pressure and retains the water phase, even though the molecular weight of the water molecule (18) is much smaller than that of the oil molecule (198 for tetradecane, used in this study). Hydrophobic membranes having pore sizes from 0.02 to 0.2 {micro}m were tested for demulsification of water-in-oil emulsions and water/oil/solid mixtures. The dispersed (aqueous)-phase drop sizes ranged from 1 to 5 {micro}m. High separation rates,more » as well as good permeate quality, were obtained with microfiltration membranes. Water content of permeating oil was 32--830 ppm depending on operating conditions and interfacial properties. For emulsions with high surfactant content, simultaneous operation of a hydrophobic and hydrophilic membrane, or simultaneous membrane separation with electric demulsification was more efficient in obtaining complete phase separation.« less

Liquid part of the phase diagram and percolation line for two-dimensional Mercedes-Benz water.

PubMed

Urbic, T

2017-09-01

Monte Carlo simulations and Wertheim's thermodynamic perturbation theory (TPT) are used to predict the phase diagram and percolation curve for the simple two-dimensional Mercedes-Benz (MB) model of water. The MB model of water is quite popular for explaining water properties, but the phase diagram has not been reported till now. In the MB model, water molecules are modeled as two-dimensional Lennard-Jones disks, with three orientation-dependent hydrogen-bonding arms, arranged as in the MB logo. The liquid part of the phase space is explored using grand canonical Monte Carlo simulations and two versions of Wertheim's TPT for associative fluids, which have been used before to predict the properties of the simple MB model. We find that the theory reproduces well the physical properties of hot water but is less successful at capturing the more structured hydrogen bonding that occurs in cold water. In addition to reporting the phase diagram and percolation curve of the model, it is shown that the improved TPT predicts the phase diagram rather well, while the standard one predicts a phase transition at lower temperatures. For the percolation line, both versions have problems predicting the correct position of the line at high temperatures.

Liquid part of the phase diagram and percolation line for two-dimensional Mercedes-Benz water

NASA Astrophysics Data System (ADS)

Urbic, T.

2017-09-01

Monte Carlo simulations and Wertheim's thermodynamic perturbation theory (TPT) are used to predict the phase diagram and percolation curve for the simple two-dimensional Mercedes-Benz (MB) model of water. The MB model of water is quite popular for explaining water properties, but the phase diagram has not been reported till now. In the MB model, water molecules are modeled as two-dimensional Lennard-Jones disks, with three orientation-dependent hydrogen-bonding arms, arranged as in the MB logo. The liquid part of the phase space is explored using grand canonical Monte Carlo simulations and two versions of Wertheim's TPT for associative fluids, which have been used before to predict the properties of the simple MB model. We find that the theory reproduces well the physical properties of hot water but is less successful at capturing the more structured hydrogen bonding that occurs in cold water. In addition to reporting the phase diagram and percolation curve of the model, it is shown that the improved TPT predicts the phase diagram rather well, while the standard one predicts a phase transition at lower temperatures. For the percolation line, both versions have problems predicting the correct position of the line at high temperatures.

Simultaneous analysis for water- and fat-soluble vitamins by a novel single chromatography technique unifying supercritical fluid chromatography and liquid chromatography.

PubMed

Taguchi, Kaori; Fukusaki, Eiichiro; Bamba, Takeshi

2014-10-03

Chromatography techniques usually use a single state in the mobile phase, such as liquid, gas, or supercritical fluid. Chromatographers manage one of these techniques for their purpose but are sometimes required to use multiple methods, or even worse, multiple techniques when the target compounds have a wide range of chemical properties. To overcome this challenge, we developed a single method covering a diverse compound range by means of a "unified" chromatography which completely bridges supercritical fluid chromatography and liquid chromatography. In our method, the phase state was continuously changed in the following order; supercritical, subcritical and liquid. Moreover, the gradient of the mobile phase starting at almost 100% CO2 was replaced with 100% methanol at the end completely. As a result, this approach achieved further extension of the polarity range of the mobile phase in a single run, and successfully enabled the simultaneous analysis of fat- and water-soluble vitamins with a wide logP range of -2.11 to 10.12. Furthermore, the 17 vitamins were exceptionally separated in 4min. Our results indicated that the use of dense CO2 and the replacement of CO2 by methanol are practical approaches in unified chromatography covering diverse compounds. Additionally, this is a first report to apply the novel approach to unified chromatography, and can open another door for diverse compound analysis in a single chromatographic technique with single injection, single column and single system. Copyright © 2014. Published by Elsevier B.V.

A soluble star-shaped silsesquioxane-cored polymer-towards novel stabilization of pH-dependent high internal phase emulsions.

PubMed

Xing, Yuxiu; Peng, Jun; Xu, Kai; Gao, Shuxi; Gui, Xuefeng; Liang, Shengyuan; Sun, Longfeng; Chen, Mingcai

2017-08-30

A well-defined pH-responsive star-shaped polymer containing poly(N,N-dimethylaminoethyl methacrylate) (PDMA) arms and a cage-like methacryloxypropyl silsesquioxane (CMSQ-T 10 ) core was used as an interfacial stabilizer for emulsions consisting of m-xylene and water. We explored the properties of the CMSQ/PDMA star-shaped polymer using the characteristic results of nuclear magnetic resonance (NMR) spectroscopy, size exclusion chromatography (SEC), dynamic light scattering (DLS), and zeta potential and conductivity measurements. The interfacial tension results showed that the CMSQ/PDMA star-shaped polymer reduced the interfacial tension between water and oil in a pH-dependent manner. Gelled high internal phase emulsions (HIPEs) including o/w and w/o types were formed in the pH ranges of 1.2-5.8 and 9.1-12.3 with the CMSQ/PDMA star-shaped polymer as a stabilizer, when the oil fractions were 80-90 vol% and 10-20 vol%, respectively. The soluble star-shaped polymer aggregated spontaneously to form a microgel that adsorbed to the two immiscible phases. Images of the fluorescently labeled polymers demonstrated that there was a star-shaped polymer in the continuous phase, and the non-Pickering stabilization based on the percolating network of the star-shaped polymer also contributed to the stabilization of the HIPE. This pH-dependent HIPE was prepared with a novel stabilization mechanism consisting of microgel adsorption and non-Pickering stabilization. Moreover, the preparation of HIPEs provided the possibility of their application in porous materials and responsive materials.

Frequency and management of breakthrough bleeding with continuous use of the transvaginal contraceptive ring: a randomized controlled trial.

PubMed

Sulak, Patricia J; Smith, Virginia; Coffee, Andrea; Witt, Iris; Kuehl, Alicia L; Kuehl, Thomas J

2008-09-01

To assess bleeding patterns with continuous use of the transvaginal contraceptive ring. We did a prospective analysis of daily menstrual flow during a 21/7 cycle followed by 6 months of continuous use and institution of a randomized protocol to manage breakthrough bleeding/spotting. Seventy-four women completed the baseline 21/7 phase and were randomized equally into two groups during the continuous phase. Group 1 was instructed to replace the ring monthly on the same calendar day with no ring-free days. Group 2 was instructed to use the same process, but if breakthrough bleeding/spotting occurred for 5 days or more, they were to remove the ring for 4 days, store it, and then reinsert that ring. Sixty-five women completed the continuous phase with reduced average flow scores in the continuous phase compared with the 21/7 phase (P<.02). Most patients had no to minimal bleeding during continuous use, with group 2 experiencing a statistically greater percentage of days without breakthrough bleeding or spotting (95%) compared with group 1 (89%) (P=.016). Instituting a 4-day hormone-free interval was more (P<.001) effective in resolving breakthrough bleeding/spotting than continuing ring use. A reduction in bleeding occurred during continuous use with replacement of the transvaginal ring compared with baseline 21/7 use. Continuous vaginal ring use resulted in an acceptable bleeding profile in most patients, reduction in flow, reduction in pelvic pain, and a high continuation rate.

Florida Agriculture - Utilizing TRMM to Analyze Sea Breeze Thunderstorm Patterns During El Nino Southern Oscillations and Their Effects Upon Available Fresh Water for South Florida Agricultural Planning and Management

NASA Technical Reports Server (NTRS)

Billiot, Amanda; Lee, Lucas; McKee, Jake; Cooley, Zachary Clayton; Mitchell, Brandie

2010-01-01

This project utilizes Tropical Rainfall Measuring Mission (TRMM) and Landsat satellite data to assess the impact of sea breeze precipitation upon areas of agricultural land use in southern Florida. Water is a critical resource to agriculture, and the availability of water for agricultural use in Florida continues to remain a key issue. Recent projections of statewide water use by 2020 estimate that 9.3 billion gallons of water per day will be demanded, and agriculture represents 47% of this demand (Bronson 2003). Farmers have fewer options for water supplies than public users and are often limited to using available supplies from surface and ground water sources which depend in part upon variable weather patterns. Sea breeze thunderstorms are responsible for much of the rainfall delivered to Florida during the wet season (May-October) and have been recognized as an important overall contributor of rainfall in southern Florida (Almeida 2003). TRMM satellite data was used to analyze how sea breeze-induced thunderstorms during El Nino and La Nina affected interannual patterns of precipitation in southern Florida from 1998-2009. TRMM's Precipitation Radar and Microwave Imager provide data to quantify water vapor in the atmosphere, precipitation rates and intensity, and the distribution of precipitation. Rainfall accumulation data derived from TRMM and other microwave sensors were used to analyze the temporal and spatial variations of rainfall during each phase of the El Nino Southern Oscillation (ENSO). Through the use of TRMM and Landsat, slight variations were observed, but it was determined that neither sea breeze nor total rainfall patterns in South Florida were strongly affected by ENSO during the study period. However, more research is needed to characterize the influence of ENSO on summer weather patterns in South Florida. This research will provide the basis for continued observations and study with the Global Precipitation Measurement Mission.

Rotational reorientation dynamics of Aerosol-OT reverse micelles formed in near-critical propane

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

Heitz, M.P.; Bright, F.V.

1996-06-01

The rotational reorientation kinetics of two fluorescent solutes (rhodamine 6G, R6G, and rhodamine 101, R101) have been determined in sodium bis(2-ethylhexyl) sulfosuccinate (Aerosol-OT, AOT) reverse micelles formed in liquid and near-critical propane. We show that the amount of water loading ([water]/[AOT], R), continuous phase density, and temperature all influence the solute rotational dynamics. In all cases, the decay of anisotropy data (i.e., frequency-dependent differential polarized phase angle and polarized modulation ratio) are well described by a bi-exponential decay law. We find that the faster rotational correlation times are similar to but slightly less than the values predicted for an individualmore » AOT reverse micelle rotating in propane. The recovered rotational correlation times range from 200 to 500 ps depending on experimental conditions. This faster rotational process is explained in terms of lateral diffusion of the fluorophore along the water/headgroup interfacial region within the reverse micelle. The recovered values for the slower rotational correlation times range from 7 to 18 ns. These larger rotational reorientation times are assigned to varying micelle-micelle (i.e., tail-tail) interactions in the low-density, highly compressible fluid region. We also quantify the contribution of the reverse micellar {open_quotes}aggregate{close_quotes} to the total decay of anisotropy. {copyright} {ital 1996} {ital Society for Applied Spectroscopy}« less

Production of Concentrated Pickering Emulsions with Narrow Size Distributions Using Stirred Cell Membrane Emulsification.

PubMed

Manga, Mohamed S; York, David W

2017-09-12

Stirred cell membrane emulsification (SCME) has been employed to prepare concentrated Pickering oil in water emulsions solely stabilized by fumed silica nanoparticles. The optimal conditions under which highly stable and low-polydispersity concentrated emulsions using the SCME approach are highlighted. Optimization of the oil flux rates and the paddle stirrer speeds are critical to achieving control over the droplet size and size distribution. Investigating the influence of oil volume fraction highlights the criticality of the initial particle loading in the continuous phase on the final droplet size and polydispersity. At a particle loading of 4 wt %, both the droplet size and polydispersity increase with increasing of the oil volume fraction above 50%. As more interfacial area is produced, the number of particles available in the continuous phase diminishes, and coincidently a reduction in the kinetics of particle adsorption to the interface resulting in larger polydisperse droplets occurs. Increasing the particle loading to 10 wt % leads to significant improvements in both size and polydispersity with oil volume fractions as high as 70% produced with coefficient of variation values as low as ∼30% compared to ∼75% using conventional homogenization techniques.

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

Fernandez-Gutierrez, Sulmer, E-mail: sulmer.a.fernandez.gutierrez@intel.com; Browning, Jim; Lin, Ming-Chieh

Phase-control of a magnetron is studied via simulation using a combination of a continuous current source and a modulated current source. The addressable, modulated current source is turned ON and OFF at the magnetron operating frequency in order to control the electron injection and the spoke phase. Prior simulation work using a 2D model of a Rising Sun magnetron showed that the use of 100% modulated current controlled the magnetron phase and allowed for dynamic phase control. In this work, the minimum fraction of modulated current source needed to achieve a phase control is studied. The current fractions (modulated versusmore » continuous) were varied from 10% modulated current to 100% modulated current to study the effects on phase control. Dynamic phase-control, stability, and start up time of the device were studied for all these cases showing that with 10% modulated current and 90% continuous current, a phase shift of 180° can be achieved demonstrating dynamic phase control.« less

Modeling water partition in composite gels of BSA with gelatin following high pressure treatment.

PubMed

Semasaka, Carine; Mhaske, Pranita; Buckow, Roman; Kasapis, Stefan

2018-11-01

Changes in the structural properties of hydrogels made with gelatin and bovine serum albumin mixtures were recorded following exposure to high pressure at 300 MPa for 15 min at 10 and 80 °C. Dynamic oscillation, SEM, FTIR and blending law modelling were utilised to rationalise results. Pressurization at the low temperature end yielded continuous gelatin networks supporting discontinuous BSA inclusions, whereas an inverted dispersion was formed at the high temperature end with the continuous BSA network suspending the discontinuous gelatin inclusions. Lewis and Nielsen equations followed the mechanical properties of the composites thus arguing that solvent partition between the two phases was always in favour of the polymer forming the continuous network. As far as we are aware, this is the first attempt to elucidate the solvent partition in pressurised hydrogel composites using blending law theory. Outcomes were contrasted with earlier work where binary mixtures were subjected only to thermal treatment. Copyright © 2018. Published by Elsevier Ltd.

Hydrophilic organic/salt-containing aqueous two-phase solvent system for counter-current chromatography: a novel technique for separation of polar compounds.

PubMed

Liu, Dan; Zou, Xiaowei; Gao, Mingzhe; Gu, Ming; Xiao, Hongbin

2014-08-22

Hydrophilic organic/salt-containing aqueous two-phase system composing of ethanol, water and ammonium sulfate for separation polar compounds was investigated on multilayer coil associated with J-type HSCCC devices. Compared to the classical polar solvent system based on 1-butanol-water or PEG1000-ammonium sulfate-water, the water content of upper phase in ethanol-ammonium sulfate-water systems was from 53.7% to 32.8% (wt%), closed to PEG1000-ammonium sulfate-water aqueous two-phase systems and higher than 1-butanol-water (22.0%, wt%). Therefore, the polarity of ethanol-ammonium sulfate-water is in the middle of 1-butanol-water and PEG-ammonium sulfate-water system, which is quite good for separating polar compounds like phenols, nucleosides and amino acids with low partition coefficient in 1-octanol-water system. The retention of stationary phase in four elution mode on type-J counter-current chromatography devices with multilayer coil column changed from 26% to 71%. Hydrodynamic trend possess both intermediate and hydrophilic solvent system property, which closely related to the composition of solvent system. The applicability of this system was demonstrated by successful separation of adenosine, uridine guanosine and cytidine. Copyright © 2014 Elsevier B.V. All rights reserved.

Slow molecular dynamics of water in a lyotropic complex fluid studied by deuterium conventional and spin-lattice relaxometry NMR.

PubMed

Rodríguez, C R; Pusiol, D J; Figueiredo Neto, A M; Seitter, R-O

2002-03-01

A nuclear magnetic resonance study of protons and deuterons in the mesomorphic phases of the micellar lyotropic mixture potassium laurate/1-decanol/heavy water is reported. The slow dynamical behavior of water molecules has been investigated with deuterons spin-lattice relaxation dispersion in the Larmor frequency range 10(3)

Comparison of lead removal behaviors and generation of water-soluble sodium compounds in molten lead glass under a reductive atmosphere

NASA Astrophysics Data System (ADS)

Okada, Takashi; Nishimura, Fumihiro; Xu, Zhanglian; Yonezawa, Susumu

2018-06-01

We propose a method of reduction-melting at 1000 °C, using a sodium-based flux, to recover lead from cathode-ray tube funnel glass. To recover the added sodium from the treated glass, we combined a reduction-melting process with a subsequent annealing step at 700 °C, generating water-soluble sodium compounds in the molten glass. Using this combined process, this study compares lead removal behavior and the generation of water-soluble sodium compounds (sodium silicates and carbonates) in order to gain fundamental information to enhance the recovery of both lead and sodium. We find that lead removal increases with increasing melting time, whereas the generation efficiency of water-soluble sodium increases and decreases periodically. In particular, near 90% lead removal, the generation of water-soluble sodium compounds decreased sharply, increasing again with the prolongation of melting time. This is due to the different crystallization and phase separation efficiencies of water-soluble sodium in molten glass, whose structure continuously changes with lead removal. Previous studies used a melting time of 60 min in the processes. However, in this study, we observe that a melting time of 180 min enhances the water-soluble sodium generation efficiency.

Berezinskii-Kosterlitz-Thouless transition and two-dimensional melting

NASA Astrophysics Data System (ADS)

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

2017-12-01

The main aspects of the theory of phase transitions in two-dimensional degenerate systems (Berezinskii-Kosterlitz-Thouless, or BKT, transitions) are reviewed in detail, including the transition mechanism, the renormalization group as a tool for describing the transition, and how the transition scenario can possibly depend on the core energy of topological defects (in particular, in thin superconducting films). Various melting scenarios in two-dimensional systems are analyzed, and the current status of actual experiments and computer simulations in the field is examined. Whereas in three dimensions melting always occurs as a single first-order transition, in two dimensions, as shown by Halperin, Nelson, and Young, melting via two continuous BKT transitions with an intermediate hexatic phase characterized by quasi-long-range orientational order is possible. But there is also a possibility for a first-order phase transition to occur. Recently, one further melting scenario, different from that occurring in the Berezinskii-Kosterlitz-Thouless-Halperin-Nelson-Young theory, has been proposed, according to which a solid can melt in two stages: a continuous BKT-type solid-hexatic transition and then a first-order hexatic-phase-isotropic-liquid phase transition. Particular attention is given to the melting scenario as a function of the potential shape and to the random pinning effect on two-dimensional melting. In particular, it is shown that random pinning can alter the melting scenario fundamentally in the case of a first-order transition. Also considered is the melting of systems with potentials having a negative curvature in the repulsion region-potentials that are successfully used in describing the anomalous properties of water in two dimensions. This review is an extended version of the report “Old and new in the physics of phase transitions” presented at the scientific session of the Physical Sciences Division of the Russian Academy of Sciences on 21 December 2016 (see Phys. Usp. 60 948-957 (2017); Usp. Fiz. Nauk 187 1021 (2017)). (Editor’s note.)

Water-quality data-collection activities in Colorado and Ohio; Phase II, Evaluation of 1984 field and laboratory quality-assurance practices

USGS Publications Warehouse

Childress, Carolyn J. Oblinger; Chaney, Thomas H.; Myers, Donna; Norris, J. Michael; Hren, Janet

1987-01-01

Serious questions have been raised by Congress about the usefulness of water-quality data for addressing issues of regional and national scope and, especially, for characterizing the current quality of the Nation's streams and ground water. In response, the U.S. Geological Survey has undertaken a pilot study in Colorado and Ohio to (1) determine the characteristics of current (1984) water-quality data-collection activities of Federal, regional, State, and local agencies, and academic institutions; and (2) determine how well the data from these activities, collected for various purposes and using different procedures, can be used to improve our ability to answer major broad-scope questions, such as:A. What are (or were) natural or near-natural water-quality conditions?B. What are existing water-quality conditions?C. How has water quality changed, and how do the changes relate to human activities?Colorado and Ohio were chosen for the pilot study largely because they represent regions with different types of waterquality concerns and programs. The study has been divided into three phases, the objectives of which are: Phase I--Inventory water-quality data-collection programs, including costs, and identify those programs that met a set of broad criteria for producing data that are potentially appropriate for water-quality assessments of regional and national scope. Phase II--Evaluate the quality assurance of field and laboratory procedures used in producing the data from programs that met the broad criteria of Phase I. Phase III--Compile the qualifying data and evaluate the adequacy of this data base for addressing selected water-quality questions of regional and national scope.Water-quality data are collected by a large number of organizations for diverse purposes ranging from meeting statutory requirements to research on water chemistry. Combining these individual data bases is an appealing and potentially cost-effective way to attempt to develop a data base adequate for regional or national water-quality assessments. However, to combine data from diverse sources, field and laboratory procedures used to produce the data need to be equivalent and need to meet specific qualityassurance standards. It is these factors that are the focus of Phase II, which is described in this report. In the first phase of this study, an inventory was made of all public organizations and academic institutions that undertook water-quality data-collection activities in Colorado and Ohio in 1984. Water-quality programs identified in Phase I were tested against a set of broad screening criteria. A total of 44 waterquality programs in Colorado and 29 programs in Ohio passed the Phase-I screen and were examined in Phase II. These programs accounted for an estimated 165,000 analyses in Colorado and 76,300 analyses in Ohio for 20 selected constituents and properties. Although qualifying programs included both surface- and ground-water sampling, they emphasized surface waters and produced few groundwater analyses (3,660 for Colorado and 470 for Ohio). For Phase II, information about field and laboratory qualityassurance practices was provided by each organization and its supporting laboratories through questionnaires. This information was evaluated against a set of specific criteria for field and laboratory practices. The criteria were developed from guidelines published by public agencies and professional organizations such as the American Public Health Association, the U.Sc, Environmental Protection Agency, and the U.S. Geological Survey. Each of the eight criteria that comprise the Phase-II screen fall into one of two major categories--field practices or laboratory practices.

40 CFR 130.9 - Designation and de-designation.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Section 130.9 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS WATER... continue water quality planning activities within the designated boundaries. (c) Impact of de-designation... responsibility for continued water quality planning and oversight of implementation within the area. (d...

Evaluation of phase II toxicity identification evaluation methods for freshwater whole sediment and interstitial water.

PubMed

Phillips, Bryn M; Anderson, Brian S; Hunt, John W; Clark, Sara L; Voorhees, Jennifer P; Tjeerdema, Ron S; Casteline, Jane; Stewart, Margaret

2009-02-01

Phase I whole sediment toxicity identification evaluation (TIE) methods have been developed to characterize the cause of toxicity as organic chemicals, metals, or ammonia. In Phase II identification treatments, resins added to whole sediment to reduce toxicity caused by metals and organics can be separated and eluted much like solid-phase extraction (SPE) columns are eluted for interstitial water. In this study, formulated reference sediments spiked with toxic concentrations of copper, fluoranthene, and nonylphenol were subjected to whole sediment and interstitial water TIE treatments to evaluate Phase I and II TIE procedures for identifying the cause of toxicity to Hyalella azteca. Phase I TIE treatments consisted of adding adsorbent resins to whole sediment, and using SPE columns to remove spiked chemicals from interstitial water. Phase II treatments consisted of eluting resins and SPE columns and the preparation and testing of eluates for toxicity and chemistry. Whole sediment resins and SPE columns significantly reduced toxicity, and the eluates from all treatments contained toxic concentrations of the spiked chemical except for interstitial water fluoranthene. Toxic unit analysis based on median lethal concentrations (LC50s) allowed for the comparison of chemical concentrations among treatments, and demonstrated that the bioavailability of some chemicals was reduced in some samples and treatments. The concentration of fluoranthene in the resin eluate closely approximated the original interstitial water concentration, but the resin eluate concentrations of copper and nonylphenol were much higher than the original interstitial water concentrations. Phase II whole sediment TIE treatments provided complementary lines of evidence to the interstitial water TIE results.

The release of dissolved nutrients and metals from coastal sediments due to resuspension

USGS Publications Warehouse

Kalnejais, Linda H.; Martin, William R.; Bothner, Michael H.

2010-01-01

Coastal sediments in many regions are impacted by high levels of contaminants. Due to a combination of shallow water depths, waves, and currents, these sediments are subject to regular episodes of sediment resuspension. However, the influence of such disturbances on sediment chemistry and the release of solutes is poorly understood. The aim of this study is to quantify the release of dissolved metals (iron, manganese, silver, copper, and lead) and nutrients due to resuspension in Boston Harbor, Massachusetts, USA. Using a laboratory-based erosion chamber, a range of typical shear stresses was applied to fine-grained Harbor sediments and the solute concentration at each shear stress was measured. At low shear stress, below the erosion threshold, limited solutes were released. Beyond the erosion threshold, a release of all solutes, except lead, was observed and the concentrations increased with shear stress. The release was greater than could be accounted for by conservative mixing of porewaters into the overlying water, suggesting that sediment resuspension enhances the release of nutrients and metals to the dissolved phase. To address the long-term fate of resuspended particles, samples from the erosion chamber were maintained in suspension for 90. h. Over this time, 5-7% of the particulate copper and silver was released to the dissolved phase, while manganese was removed from solution. Thus resuspension releases solutes both during erosion events and over a longer timescale due to reactions of suspended particles in the water column. The magnitude of the annual solute release during erosion events was estimated by coupling the erosion chamber results with a record of bottom shear stresses simulated by a hydrodynamic model. The release of dissolved copper, lead, and phosphate due to resuspension is between 2% and 10% of the total (dissolved plus particulate phase) known inputs to Boston Harbor. Sediment resuspension is responsible for transferring a significant quantity of solid phase metals to the more bioavailable and mobile dissolved phase. The relative importance of sediment resuspension as a source of dissolved metals to Boston Harbor is expected to increase as continuing pollutant control decreases the inputs from other sources. ?? 2010 Elsevier B.V.

Convective heat transfer in foams under laminar flow in pipes and tube bundles.

PubMed

Attia, Joseph A; McKinley, Ian M; Moreno-Magana, David; Pilon, Laurent

2012-12-01

The present study reports experimental data and scaling analysis for forced convection of foams and microfoams in laminar flow in circular and rectangular tubes as well as in tube bundles. Foams and microfoams are pseudoplastic (shear thinning) two-phase fluids consisting of tightly packed bubbles with diameters ranging from tens of microns to a few millimeters. They have found applications in separation processes, soil remediation, oil recovery, water treatment, food processes, as well as in fire fighting and in heat exchangers. First, aqueous solutions of surfactant Tween 20 with different concentrations were used to generate microfoams with various porosity, bubble size distribution, and rheological behavior. These different microfoams were flowed in uniformly heated circular tubes of different diameter instrumented with thermocouples. A wide range of heat fluxes and flow rates were explored. Experimental data were compared with analytical and semi-empirical expressions derived and validated for single-phase power-law fluids. These correlations were extended to two-phase foams by defining the Reynolds number based on the effective viscosity and density of microfoams. However, the local Nusselt and Prandtl numbers were defined based on the specific heat and thermal conductivity of water. Indeed, the heated wall was continuously in contact with a film of water controlling convective heat transfer to the microfoams. Overall, good agreement between experimental results and model predictions was obtained for all experimental conditions considered. Finally, the same approach was shown to be also valid for experimental data reported in the literature for laminar forced convection of microfoams in rectangular minichannels and of macrofoams across aligned and staggered tube bundles with constant wall heat flux.

Aqueous photooxidation of ambient Po Valley Italy air samples: Insights into secondary organic aerosol formation

NASA Astrophysics Data System (ADS)

Kirkland, J. R.; Lim, Y. B.; Sullivan, A. P.; Decesari, S.; Facchini, C.; Collett, J. L.; Keutsch, F. N.; Turpin, B. J.

2012-12-01

In this work, we conducted aqueous photooxidation experiments with ambient samples in order to develop insights concerning the formation of secondary organic aerosol through gas followed by aqueous chemistry (SOAaq). Water-soluble organics (e.g., glyoxal, methylglyoxal, glycolaldehyde, acetic acid, acetone) are formed through gas phase oxidation of alkene and aromatic emissions of anthropogenic and biogenic origin. Their further oxidation in clouds, fogs and wet aerosols can form lower volatility products (e.g., oligomers, organic acids) that remain in the particle phase after water evaporation, thus producing SOA. The aqueous OH radical oxidation of several individual potentially important precursors has been studied in the laboratory. In this work, we used a mist-chamber apparatus to collect atmospheric mixtures of water-soluble gases from the ambient air at San Pietro Capofiume, Italy during the PEGASOS field campaign. We measured the concentration dynamics after addition of OH radicals, in order to develop new insights regarding formation of SOA through aqueous chemistry. Specifically, batch aqueous reactions were conducted with 33 ml mist-chamber samples (TOC ~ 50-100μM) and OH radicals (~10-12M) in a new low-volume aqueous reaction vessel. OH radicals were formed in-situ, continuously by H2O2 photolysis. Products were analyzed by ion chromatography (IC), electrospray ionization mass spectrometry (ESI-MS +/-), and ESI-MS with IC pre-separation (IC/ESI-MS-). Reproducible formation of pyruvate and oxalate were observed both by IC and ESI-MS. These compounds are known to form from aldehyde oxidation in the aqueous phase. New insights regarding the aqueous chemistry of these "more atmospherically-realistic" experiments will be discussed.

Thermal Energy Storage using PCM for Solar Domestic Hot Water Systems: A Review

NASA Astrophysics Data System (ADS)

Khot, S. A.; Sane, N. K.; Gawali, B. S.

2012-06-01

Thermal energy storage using phase chase materials (PCM) has received considerable attention in the past two decades for time dependent energy source such as solar energy. From several experimental and theoretical analyses that have been made to assess the performance of thermal energy storage systems, it has been demonstrated that PCM-based systems are reliable and viable options. This paper covers such information on PCMs and PCM-based systems developed for the application of solar domestic hot water system. In addition, economic analysis of thermal storage system using PCM in comparison with conventional storage system helps to validate its commercial possibility. From the economic analysis, it is found that, PCM based solar domestic hot water system (SWHS) provides 23 % more cumulative and life cycle savings than conventional SWHS and will continue to perform efficiently even after 15 years due to application of non-metallic tank. Payback period of PCM-based system is also less compared to conventional system. In conclusion, PCM based solar water heating systems can meet the requirements of Indian climatic situation in a cost effective and reliable manner.

How internal drainage affects evaporation dynamics from soil surfaces ?

NASA Astrophysics Data System (ADS)

Or, D.; Lehmann, P.; Sommer, M.

2017-12-01

Following rainfall, infiltrated water may be redistributed internally to larger depths or lost to the atmosphere by evaporation (and by plant uptake from depths at longer time scales). A large fraction of evaporative losses from terrestrial surfaces occurs during stage1 evaporation during which phase change occurs at the wet surface supplied by capillary flow from the soil. Recent studies have shown existence of a soil-dependent characteristic length below which capillary continuity is disrupted and a drastic shift to slower stage 2 evaporation ensues. Internal drainage hastens this transition and affect evaporative losses. To predict the transition to stage 2 and associated evaporative losses, we developed an analytical solution for evaporation dynamics with concurrent internal drainage. Expectedly, evaporative losses are suppressed when drainage is considered to different degrees depending on soil type and wetness. We observe that high initial water content supports rapid drainage and thus promotes the sheltering of soil water below the evaporation depth. The solution and laboratory experiments confirm nonlinear relationship between initial water content and total evaporative losses. The concept contributes to establishing bounds on regional surface evaporation considering rainfall characteristics and soil types.

IN SITU OXIDATION AND ASSOCIATED MASS-FLUX-REDUCTION/MASS-REMOVAL BEHAVIOR FOR SYSTEMS WITH ORGANIC LIQUID LOCATED IN LOWER-PERMEABILITY SEDIMENTS

PubMed Central

Marble, Justin C.; Carroll, Kenneth C.; Janousek, Hilary; Brusseau, Mark L.

2010-01-01

The effectiveness of permanganate for in situ chemical oxidation of organic liquid (trichloroethene) trapped in lower-permeability (K) zones located within a higher-permeability matrix was examined in a series of flow-cell experiments. The permanganate solution was applied in both continuous and pulsed-injection modes. Manganese-oxide precipitation, as confirmed by use of SEM-EDS, occurred within, adjacent to, and downgradient of the lower-K zones, reflective of trichloroethene oxidation. During flow interruptions, precipitate formed within the surrounding higher-permeability matrix, indicating diffusive flux of aqueous-phase trichloroethene from the lower-K zones. The impact of permanganate treatment on mass flux behavior was examined by conducting water floods after permanganate injection. The results were compared to those of water-flood control experiments. The amount of water flushing required for complete contaminant mass removal was reduced for all permanganate treatments for which complete removal was characterized. However, the nature of the mass-flux-reduction/mass-removal relationship observed during water flooding varied as a function of the specific permanganate treatment. PMID:20685008

Soil Water Content Sensors as a Method of Measuring Ice Depth

NASA Astrophysics Data System (ADS)

Whitaker, E.; Reed, D. E.; Desai, A. R.

2015-12-01

Lake ice depth provides important information about local and regional climate change, weather patterns, and recreational safety, as well as impacting in situ ecology and carbon cycling. However, it is challenging to measure ice depth continuously from a remote location, as existing methods are too large, expensive, and/or time-intensive. Therefore, we present a novel application that reduces the size and cost issues by using soil water content reflectometer sensors. Analysis of sensors deployed in an environmental chamber using a scale model of a lake demonstrated their value as accurate measures of the change in ice depth over any time period, through measurement of the liquid-to-solid phase change. A robust correlation exists between volumetric water content in time as a function of environmental temperature. This relationship allows us to convert volumetric water content into ice depth. An array of these sensors will be placed in Lake Mendota, Madison, Wisconsin in winter 2015-2016, to create a temporally high-resolution ice depth record, which will be used for ecological or climatological studies while also being transmitted to the public to increase recreational safety.

Responses of Cloud Type Distributions to the Large-Scale Dynamical Circulation: Water Budget-Related Dynamical Phase Space and Dynamical Regimes

NASA Technical Reports Server (NTRS)

Wong, Sun; Del Genio, Anthony; Wang, Tao; Kahn, Brian; Fetzer, Eric J.; L'Ecuyer, Tristan S.

2015-01-01

Goals: Water budget-related dynamical phase space; Connect large-scale dynamical conditions to atmospheric water budget (including precipitation); Connect atmospheric water budget to cloud type distributions.

Comparison of electrical and optical characteristics in gas-phase and gas-liquid phase discharges

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

Qazi, H. I. A.; Li, He-Ping, E-mail: liheping@tsinghua.edu.cn; Zhang, Xiao-Fei

This paper presents an AC-excited argon discharge generated using a gas-liquid (two-phase) hybrid plasma reactor, which mainly consists of a powered needle electrode enclosed in a conical quartz tube and grounded deionized water electrode. The discharges in the gas-phase, as well as in the two-phase, exhibit two discharge modes, i.e., the low current glow-like diffuse mode and the high current streamer-like constrict mode, with a mode transition, which exhibits a negative resistance of the discharges. The optical emission spectral analysis shows that the stronger diffusion of the water vapor into the discharge region in the two-phase discharges boosts up themore » generation of OH (A–X) radicals, and consequently, leads to a higher rotational temperature in the water-phase plasma plume than that of the gas-phase discharges. Both the increase of the power input and the decrease of the argon flow rate result in the increase of the rotational temperature in the plasma plume of the water-phase discharge. The stable two-phase discharges with a long plasma plume in the water-phase under a low power input and gas flow rate may show a promising prospect for the degradation of organic pollutants, e.g., printing and dyeing wastewater, in the field of environmental protection.« less