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Sample records for saturated salt solutions

  1. Saturated salt solution method: a useful cadaver embalming for surgical skills training.

    PubMed

    Hayashi, Shogo; Homma, Hiroshi; Naito, Munekazu; Oda, Jun; Nishiyama, Takahisa; Kawamoto, Atsuo; Kawata, Shinichi; Sato, Norio; Fukuhara, Tomomi; Taguchi, Hirokazu; Mashiko, Kazuki; Azuhata, Takeo; Ito, Masayuki; Kawai, Kentaro; Suzuki, Tomoya; Nishizawa, Yuji; Araki, Jun; Matsuno, Naoto; Shirai, Takayuki; Qu, Ning; Hatayama, Naoyuki; Hirai, Shuichi; Fukui, Hidekimi; Ohseto, Kiyoshige; Yukioka, Tetsuo; Itoh, Masahiro

    2014-12-01

    This article evaluates the suitability of cadavers embalmed by the saturated salt solution (SSS) method for surgical skills training (SST). SST courses using cadavers have been performed to advance a surgeon's techniques without any risk to patients. One important factor for improving SST is the suitability of specimens, which depends on the embalming method. In addition, the infectious risk and cost involved in using cadavers are problems that need to be solved. Six cadavers were embalmed by 3 methods: formalin solution, Thiel solution (TS), and SSS methods. Bacterial and fungal culture tests and measurement of ranges of motion were conducted for each cadaver. Fourteen surgeons evaluated the 3 embalming methods and 9 SST instructors (7 trauma surgeons and 2 orthopedists) operated the cadavers by 21 procedures. In addition, ultrasonography, central venous catheterization, and incision with cauterization followed by autosuture stapling were performed in some cadavers. The SSS method had a sufficient antibiotic effect and produced cadavers with flexible joints and a high tissue quality suitable for SST. The surgeons evaluated the cadavers embalmed by the SSS method to be highly equal to those embalmed by the TS method. Ultrasound images were clear in the cadavers embalmed by both the methods. Central venous catheterization could be performed in a cadaver embalmed by the SSS method and then be affirmed by x-ray. Lungs and intestines could be incised with cauterization and autosuture stapling in the cadavers embalmed by TS and SSS methods. Cadavers embalmed by the SSS method are sufficiently useful for SST. This method is simple, carries a low infectious risk, and is relatively of low cost, enabling a wider use of cadavers for SST. PMID:25501070

  2. Saturated Salt Solution Method: A Useful Cadaver Embalming for Surgical Skills Training

    PubMed Central

    Hayashi, Shogo; Homma, Hiroshi; Naito, Munekazu; Oda, Jun; Nishiyama, Takahisa; Kawamoto, Atsuo; Kawata, Shinichi; Sato, Norio; Fukuhara, Tomomi; Taguchi, Hirokazu; Mashiko, Kazuki; Azuhata, Takeo; Ito, Masayuki; Kawai, Kentaro; Suzuki, Tomoya; Nishizawa, Yuji; Araki, Jun; Matsuno, Naoto; Shirai, Takayuki; Qu, Ning; Hatayama, Naoyuki; Hirai, Shuichi; Fukui, Hidekimi; Ohseto, Kiyoshige; Yukioka, Tetsuo; Itoh, Masahiro

    2014-01-01

    Abstract This article evaluates the suitability of cadavers embalmed by the saturated salt solution (SSS) method for surgical skills training (SST). SST courses using cadavers have been performed to advance a surgeon's techniques without any risk to patients. One important factor for improving SST is the suitability of specimens, which depends on the embalming method. In addition, the infectious risk and cost involved in using cadavers are problems that need to be solved. Six cadavers were embalmed by 3 methods: formalin solution, Thiel solution (TS), and SSS methods. Bacterial and fungal culture tests and measurement of ranges of motion were conducted for each cadaver. Fourteen surgeons evaluated the 3 embalming methods and 9 SST instructors (7 trauma surgeons and 2 orthopedists) operated the cadavers by 21 procedures. In addition, ultrasonography, central venous catheterization, and incision with cauterization followed by autosuture stapling were performed in some cadavers. The SSS method had a sufficient antibiotic effect and produced cadavers with flexible joints and a high tissue quality suitable for SST. The surgeons evaluated the cadavers embalmed by the SSS method to be highly equal to those embalmed by the TS method. Ultrasound images were clear in the cadavers embalmed by both the methods. Central venous catheterization could be performed in a cadaver embalmed by the SSS method and then be affirmed by x-ray. Lungs and intestines could be incised with cauterization and autosuture stapling in the cadavers embalmed by TS and SSS methods. Cadavers embalmed by the SSS method are sufficiently useful for SST. This method is simple, carries a low infectious risk, and is relatively of low cost, enabling a wider use of cadavers for SST. PMID:25501070

  3. History and future of human cadaver preservation for surgical training: from formalin to saturated salt solution method.

    PubMed

    Hayashi, Shogo; Naito, Munekazu; Kawata, Shinichi; Qu, Ning; Hatayama, Naoyuki; Hirai, Shuichi; Itoh, Masahiro

    2016-01-01

    Traditionally, surgical training meant on-the-job training with live patients in an operating room. However, due to advancing surgical techniques, such as minimally invasive surgery, and increasing safety demands during procedures, human cadavers have been used for surgical training. When considering the use of human cadavers for surgical training, one of the most important factors is their preservation. In this review, we summarize four preservation methods: fresh-frozen cadaver, formalin, Thiel's, and saturated salt solution methods. Fresh-frozen cadaver is currently the model that is closest to reality, but it also presents myriad problems, including the requirement of freezers for storage, limited work time because of rapid putrefaction, and risk of infection. Formalin is still used ubiquitously due to its low cost and wide availability, but it is not ideal because formaldehyde has an adverse health effect and formalin-embalmed cadavers do not exhibit many of the qualities of living organs. Thiel's method results in soft and flexible cadavers with almost natural colors, and Thiel-embalmed cadavers have been appraised widely in various medical disciplines. However, Thiel's method is relatively expensive and technically complicated. In addition, Thiel-embalmed cadavers have a limited dissection time. The saturated salt solution method is simple, carries a low risk of infection, and is relatively low cost. Although more research is needed, this method seems to be sufficiently useful for surgical training and has noteworthy features that expand the capability of clinical training. The saturated salt solution method will contribute to a wider use of cadavers for surgical training. PMID:26670696

  4. Report on variation of electrical conductivity during steam injection in unconsolidated sand saturated with a salt solution

    SciTech Connect

    Vaughan, P.; Udell, K.S.; Wilt, M.

    1992-04-01

    Geophysical electrical methods are useful in evaluating the performance of certain classes of enhanced oil recovery (EOR) operations and also remediation operations for contaminant spills. Electrical resistivity is sensitive to the concentration of ionic species in solution in fluids present in the subsurface zone. Such fluids are displaced during oil recovery operations and contaminant remediation. If the resistivity of the displacing fluid differs from the in situ fluid, then a geophysical method for detecting resistivity variations may be capable of tracking the advance of the displacing fluid. This report presents the results of experiments designed to determine the variations in resistivity that occur when steam is injected into a homogeneous, fully-saturated sand. These experiments were simple, one-dimensional laboratory steam injection experiments. They were performed using a glass tube filled with a tightly-packed sand and fitted with an injection port at one end and an exit port at the other In each experiment, the sand pack was initially saturated with a brine and then steam was introduced at one end of the tube. Analytic solutions for the steam front velocity, steam temperature, steam distribution, salt concentration profile, and liquid saturation are presented and are used with appropriate correlations of electrical conductivity to describe the observed behavior. The results of these experiments should provide experimental justification for the electrical conductivity variations that are calculated from the analytic solutions. In addition, the experiments may yield new information regarding features of the data that may not result from the analytical modelling.

  5. Limitations of amorphous content quantification by isothermal calorimetry using saturated salt solutions to control relative humidity: alternative methods.

    PubMed

    Khalef, Nawel; Pinal, Rodolfo; Bakri, Aziz

    2010-04-01

    Despite the high sensitivity of isothermal calorimetry (IC), reported measurements of amorphous content by this technique show significant variability even for the same compound. An investigation into the reasons behind such variability is presented using amorphous lactose and salbutamol sulfate as model compounds. An analysis was carried out on the heat evolved as a result of the exchange of water vapor between the solid sample during crystallization and the saline solution reservoir. The use of saturated salt solutions as means of control of the vapor pressure of water within sealed ampoules bears inherent limitations that lead in turn to the variability associated with the IC technique. We present an alternative IC method, based on an open cell configuration that effectively addresses the limitations encountered with the sealed ampoule system. The proposed approach yields an integral whose value is proportional to the amorphous content in the sample, thus enabling reliable and consistent quantifications. PMID:19774655

  6. Interfacial behavior of perchlorate versus chloride ions in saturated aqueous salt solutions

    SciTech Connect

    Ghosal, S; Kuo, I W; Baer, M D; Bluhm, H

    2009-04-14

    In recent years combination of theoretical and experimental work have presented a novel view of the aqueous interface wherein hard and/or multiply charged ions are excluded from the interface, but large polarizable anions show interfacial enhancement relative to the bulk. The observed trend in the propensity of anions to adsorb at the air/water interface appears to be reverse of the Hofmeister series for anions. This study focuses on experimental and theoretical examination of the partitioning behavior of perchlorate (ClO{sub 4}{sup -}) and chloride (Cl{sup -}) ions at the air/water interface. We have used ambient pressure X-ray photoelectron spectroscopy technique to directly probe the interfacial concentrations of ClO{sub 4}{sup -} and Cl{sup -} ions in sodium perchlorate and sodium chloride solutions, respectively. Experimental observations are compared with first principles molecular dynamics simulations. Both experimental and simulation results show enhancement of ClO{sub 4}{sup -} ion at the interface, compared with the absence of such enhancement in the case of Cl{sup -} ion. These observations are in agreement with the expected trend in the interfacial propensity of anions based on the Hofmeister series.

  7. Experimental Microbiology of Saturated Salt Solutions and Other Harsh Environments. III. Growth of Salt-Tolerant Penicillium notatum in Boron-Rich Media 1

    PubMed Central

    Roberts, Karen; Siegel, S. M.

    1967-01-01

    A stress-tolerant strain of Penicillium notatum, isolated by passage through a nutrient solution saturated with calcium acetate, was found to have a tolerance to boron in several states of oxidation. Growth in the presence of elementary boron, saturating amounts of boric acid, and with various concentrations of sodium borohydride was observed and mycelial mats were spectrographically analyzed for boron accumulation. PMID:6076112

  8. The effects of steam injection on the electrical conductivity of an unconsolidated sand saturated with a salt solution

    SciTech Connect

    Vaughan, P.J.; Udell, K.S. ); Wilt, M.J. )

    1993-01-10

    The spatial and temporal variation of electrical conductivity in saturated sands during steam injection has been measured and modeled. Experiments consisted of introducing steam into one end of a tube filled with sand saturated with a slightly saline solution. A steam condensation front formed, separating the mixed-phase steam zone from the liquid zone. Measurements of electrical conductivity were made at 10 locations along the tube using a four-electrode technique. Results show that conductivity starts at a constant value, decreases before the steam front arrives and then, immediately prior to the steam front arrival, goes through a maximum before dropping by a factor of about 25. These variations can be explained by first, a dilution of the interstitial solution causing the initial drop in conductivity; second, an increase in temperature of the solution immediately prior to the arrival of the steam front causing the conductivity maximum; and finally, the large drop in conductivity due to the combined effects of a decrease in saturation and dilution of the residual liquid in the two-phase zone. Mathematical solutions of a set of differential equations that take into consideration all of these effects are presented. These solutions reproduce the significant features of the conductivity data. This study suggests that the measurement of changes in the subsurface conductivity field during steam injection operations may indicate the location of ionic concentration, temperature, and steam saturation fields. 28 refs., 7 figs., 1 tab.

  9. Report on variation of electrical conductivity during steam injection in unconsolidated sand saturated with a salt solution

    SciTech Connect

    Vaughn, P.; Udell, K.S.; Wilt, M.

    1992-07-01

    The spatial and temporal variation electrical conductivity in saturated sands during steam injection has been measured and modeled. Experiments consisted of introducing steam into an end of a tube filled with a sand saturated with a slightly saline solution. Measurements of electrical conductivity were then made every 10 seconds at 10 locations along the tube using a four electrode technique. After injection a steam condensation front forms ahead of the steam front that separates the mixed-phase steam zone from the liquid zone. Conductivity measurements at a specific position in the tube throughout time show that the electrical conductivity starts at a constant value, decreases before the steam front arrives and then, immediately prior to the steam front arrival, goes through a maximum before dropping by a factor about 25. These variations can be explained by first: a dilution of the interstitial solution ahead of the steam front thereby causing the initial drop in conductivity; second, an increase in temperature of the solution immediately prior to the arrival of the steam front causing the conductivity maximum; and finally the large drop in conductivity due to the combined effects of a decrease in saturation and dilution of the residual liquid in the two-phase zone. Mathematical solutions of a set of differential equations that take into consideration all of these effects are presented. These solutions reproduce the significant features of the conductivity data, and help to explain the physical phenomenon. The study suggests that the measurements of changes in the subsurface conductivity field during steam injection operations may indicate the location of ionic concentration, temperature, and steam saturation fields.

  10. Salt-saturated concrete strength and permeability

    SciTech Connect

    Pfeifle, T.W.

    1996-11-01

    Laboratory-scale experiments applicable to the use of salt-saturated concrete as a seal material for a transuranic waste repository have been completed. Nitrogen gas permeability measurements were made using a flexible-wall permeameter, a confining pressure of 1 MPa, and gas pressure gradients ranging from 0.3 MPa to 0.75 MPa. Results show that salt-saturated concrete has very low intrinsic permeability with values ranging from 9.4 {times} 10{sup {minus}22} m{sup 2} to 9.7 {times} 10{sup {minus}17} m{sup 2}. Strength and deformation characteristics were investigated under conditions of triaxial compression with confining pressures ranging from 0 to 15 MPa using either axial strain-rate or axial stress-rate control and show that the failure strength of concrete increases with confining pressure which can be adequately described through pressure-sensitive failure criteria. Axial, radial, and volumetric strains were also measured during each test and these data were used to determine elastic properties. Experimental results are applicable in the design and analysis of scale-related functions and apply to other concrete structures subjected to compressive loadings such as dams and prestressed structural members.

  11. Study of actinide chemistry in saturated potassium fluoride solution

    NASA Technical Reports Server (NTRS)

    Cohen, D.; Thalmayer, C. E.

    1969-01-01

    Study concerning the chemistry of actinides in saturated KF solution included work with neptunium, uranium, and americium. Solubilities, absorption spectra, oxidation-reduction reactions, and solid compounds which can be produced in KF solution were examined. The information is used for preparation of various materials from salts of the actinides.

  12. Electrochromic salts, solutions, and devices

    DOEpatents

    Burrell, Anthony K.; Warner, Benjamin P.; McClesky,7,064,212 T. Mark

    2006-06-20

    Electrochromic salts. Electrochromic salts of dicationic viologens such as methyl viologen and benzyl viologen associated with anions selected from bis(trifluoromethylsulfonyl)imide, bis(perfluoroethylsulfonyl)imide, and tris(trifluoromethylsulfonyl)methide are produced by metathesis with the corresponding viologen dihalide. They are highly soluble in molten quarternary ammonium salts and together with a suitable reductant provide electrolyte solutions that are used in electrochromic windows.

  13. Electrochromic Salts, Solutions, and Devices

    DOEpatents

    Burrell, Anthony K.; Warner, Benjamin P.; McClesky, T. Mark

    2008-10-14

    Electrochromic salts. Electrochromic salts of dicationic viologens such as methyl viologen and benzyl viologen associated with anions selected from bis(trifluoromethylsulfonyl)imide, bis(perfluoroethylsulfonyl)imide, and tris(trifluoromethylsulfonyl)methide are produced by metathesis with the corresponding viologen dihalide. They are highly soluble in molten quarternary ammonium salts and together with a suitable reductant provide electrolyte solutions that are used in electrochromic windows.

  14. Electrochromic Salts, Solutions, and Devices

    DOEpatents

    Burrell, Anthony K.; Warner, Benjamin P.; McClesky, T. Mark

    2008-11-11

    Electrochromic salts. Electrochromic salts of dicationic viologens such as methyl viologen and benzyl viologen associated with anions selected from bis(trifluoromethylsulfonyl)imide, bis(perfluoroethylsulfonyl)imide, and tris(trifluoromethylsulfonyl)methide are produced by metathesis with the corresponding viologen dihalide. They are highly soluble in molten quarternary ammonium salts and together with a suitable reductant provide electrolyte solutions that are used in electrochromic windows.

  15. Protein aggregation in salt solutions

    PubMed Central

    Kastelic, Miha; Kalyuzhnyi, Yurij V.; Hribar-Lee, Barbara; Dill, Ken A.; Vlachy, Vojko

    2015-01-01

    Protein aggregation is broadly important in diseases and in formulations of biological drugs. Here, we develop a theoretical model for reversible protein–protein aggregation in salt solutions. We treat proteins as hard spheres having square-well-energy binding sites, using Wertheim’s thermodynamic perturbation theory. The necessary condition required for such modeling to be realistic is that proteins in solution during the experiment remain in their compact form. Within this limitation our model gives accurate liquid–liquid coexistence curves for lysozyme and γ IIIa-crystallin solutions in respective buffers. It provides good fits to the cloud-point curves of lysozyme in buffer–salt mixtures as a function of the type and concentration of salt. It than predicts full coexistence curves, osmotic compressibilities, and second virial coefficients under such conditions. This treatment may also be relevant to protein crystallization. PMID:25964322

  16. Salting-out and Salting-in in Polyelectrolyte Solutions

    NASA Astrophysics Data System (ADS)

    Zhang, Pengfei; Wu, Jianzhong; Wang, Zhen-Gang

    The phase behavior of polyelectrolyte (PE) solutions is governed by complicated interplay involving the mixing entropy, excluded volume, chain connectivity, and electrostatic interactions. Here we study the phase behavior of PE solutions in both salt-free condition and with added salt using a liquid-state (LS) theory based thermodynamic model. The LS model accounts or the hard-core repulsion by the Canahan-Starling equation of state, correlations due to chain connectivity by the first-order thermodynamic perturbation theory, and electrostatic correlations by the mean-spherical approximation. In comparison to the prediction from the well-known Voorn-Overbeek theory, the LS model predicts loop-type binodal curves in the salt-PE concentration diagram at temperatures slightly above the critical temperature of PE solution in salt-free case, consistent with the experimental study. The phase separated region shrinks with increasing temperature. Three scenarios of salting-out and salting-in phenomenon are predicted with addition of salts based, depending on the PE concentration.

  17. SEPARATION OF INORGANIC SALTS FROM ORGANIC SOLUTIONS

    DOEpatents

    Katzin, L.I.; Sullivan, J.C.

    1958-06-24

    A process is described for recovering the nitrates of uranium and plutonium from solution in oxygen-containing organic solvents such as ketones or ethers. The solution of such salts dissolved in an oxygen-containing organic compound is contacted with an ion exchange resin whereby sorption of the entire salt on the resin takes place and then the salt-depleted liquid and the resin are separated from each other. The reaction seems to be based on an anion formation of the entire salt by complexing with the anion of the resin. Strong base or quaternary ammonium type resins can be used successfully in this process.

  18. Ammonia Solubility in High Concentration Salt Solutions

    SciTech Connect

    HEDENGREN, D.C.

    2000-02-01

    Solubility data for ammonia in water and various dilute solutions are abundant in the literature. However, there is a noticeable lack of ammonia solubility data for high salt, basic solutions of various mixtures of salts including those found in many of the Hanford Washington underground waste tanks. As a result, models based on solubility data for dilute salt solutions have been used to extrapolate to high salt solutions. These significant extrapolations need to be checked against actual laboratory data. Some indirect vapor measurements have been made. A more direct approach is to determine the ratio of solubility of ammonia in water to its solubility in high salt solutions. In various experiments, pairs of solutions, one of which is water and the other a high salt solution, are allowed to come to equilibrium with a common ammonia vapor pressure. The ratio of concentrations of ammonia in the two solutions is equal to the ratio of the respective ammonia solubilities (Henry's Law constants) at a given temperature. This information can then be used to refine the models that predict vapor space compositions of ammonia. Ammonia at Hanford is of concern because of its toxicity in the environment and its contribution to the flammability of vapor space gas mixtures in waste tanks.

  19. Coordination chemistry in fused-salt solutions

    NASA Technical Reports Server (NTRS)

    Gruen, D. M.

    1969-01-01

    Spectrophotometric work on structural determinations with fused-salt solutions is reviewed. Constraints placed on the method, as well as interpretation of the spectra, are discussed with parallels drawn to aqueous spectrophotometric curves of the same materials.

  20. Solubility of uranium in alkaline salt solutions

    SciTech Connect

    Hobbs, D.T.; Edwards, T.B.

    1994-03-29

    The solubility of uranium in alkaline salt solutions was investigated to screen for significant factors and interactions among the major salt components and temperature. The components included in the study were the sodium salts of hydroxide, nitrate, nitrite, aluminate, sulfate, and carbonate. General findings from the study included: (1) uranium solubilities are very low (1-20 mg/L) for all solution compositions at hydroxide concentrations from 0.1 to 17 molar (2) carbonate, sulfate, and aluminate are not effective complexants for uranium at high hydroxide concentration, (3) uranium solubility decreases with increasing temperature for most alkaline salt solutions, and (4) uranium solubility increases with changes in solution chemistry that reflect aging of high level waste (increase in nitrite and carbonate concentrations, decrease in nitrate and hydroxide concentrations). A predictive model for the concentration of uranium as a function of component concentrations and temperature was fitted to the data. All of the solution components and temperature were found to be significant. There is a significant lack of fit for the model, which suggests that the dependence on the uranium solubility over the wide range of solution compositions is non-linear and/or that there are other uncontrolled parameters which are important to the uranium solubility.

  1. Scattering by solutions of major sea salts.

    PubMed

    Zhang, Xiaodong; Hu, Lianbo; Twardowski, Michael S; Sullivan, James M

    2009-10-26

    Increased scattering by seawater relative to that by pure water is primarily due to additional fluctuation of the refractive index contributed by sea salts. Salts with different ionic weight and sizes, while barely affecting the scattering that is due to density fluctuations, have a significant effect on the scattering that is due to concentration fluctuations. And this explains the major differences of their total scattering that would be observed. Scattering by solutions of NaCl, the major sea salt, is consistently about 6.7% and 4% lower than seawater of the same mass concentration and of the same refractive index, respectively. Because of ionic interactions, the molecular scattering does not follow the simple addition rule that applies to bulk inherent optical properties, with the total less than the summation of the parts. The possible values of scattering by waters of, such as, Dead Sea or Orca Basin, which have different salt composition from seawater, are discussed. PMID:19997177

  2. ANALYTICAL SOLUTION TO SATURATED FLOW IN A FINITE STRATIFIED AQUIFER

    EPA Science Inventory

    An analytical solution for the flow of water in a saturated-stratified aquitard-aquifer-aquitard system of finite length is presented. The analytical solution assumes one-dimensional horizontal flow in the aquifer and two-dimensional flow in the aquitards. Several examples are gi...

  3. Americium separations from high salt solutions

    SciTech Connect

    Mary E. Barr; Gordon D. Jarvinen; Louis D. Schulte; Peter C. Stark; Rebecca M. Chamberlin; Kent D. Abney; Thomas E. Ricketts; Yvette E. Valdez; Richard A. Bartsch

    2000-03-01

    Americium (III) exhibits an unexpectedly high affinity for anion-exchange material from the high-salt evaporator bottoms solutions--an effect which has not been duplicated using simple salt solutions. Similar behavior is observed for its lanthanide homologue, Nd(III), in complex evaporator bottoms surrogate solutions. There appears to be no single controlling factor--acid concentration, total nitrate concentration or solution ionic strength--which accounts for the approximately 2-fold increase in retention of the trivalent ions from complex solutions relative to simple solutions. Calculation of species activities (i.e., water, proton and nitrate) in such concentrated mixed salt solutions is difficult and of questionable accuracy, but it is likely that the answer to forcing formation of anionic nitrate complexes of americium lies in the relative activities of water and nitrate. From a practical viewpoint, the modest americium removal needs (ca. 50--75%) from nitric acid evaporator bottoms allow sufficient latitude for the use of non-optimized conditions such as running existing columns filled with older, well-used Reillex HPQ. Newer materials, such as HPQ-100 and the experimental bifunctional resins, which exhibit higher distribution coefficients, would allow for either increased Am removal or the use of smaller columns. It is also of interest that one of the experimental neutral-donor solid-support extractants, DHDECMP, exhibits a similarly high level of americium (total alpha) removal from EV bottoms and is much less sensitive to total acid content than commercially-available material.

  4. HORSMIC. Horizontal Salt Solution Mining Model

    SciTech Connect

    Russo, A.J.

    1994-01-01

    The code HORSMIC was written to solve the problem of calculating the shape of hydrocarbon (gas or liquid) storage caverns formed by solution mining in bedded salt formations. In the past many storage caverns have been formed by vertically drilling into salt dome formations and solution mining large-aspect-ratio, vertically axisymmetric caverns. This approach is generally not satisfactory for shallow salt beds because it would result in geomechanically-unstable, pancake-shaped caverns. In order to produce a high aspect ratio cavern in the horizontal direction a more complicated strategy must be employed. This code was developed to implement such a strategy, and can be used to estimate the shape of the cavern produced by a prescribed leaching schedule. Multiple trials can then be used to investigate the effects of various pipe hole configurations in order to optimize over the cavern shape.

  5. Oscillations in a Linearly Stratified Salt Solution

    ERIC Educational Resources Information Center

    Heavers, Richard M.

    2007-01-01

    Our physics students like to watch a ball bouncing underwater. They do this by dropping a weighted plastic ball into a 1000-ml cylinder filled with a linearly stratified salt-water solution at room temperature. The ball oscillates and comes to rest at about mid-depth. Its motion is analogous to the damped vertical oscillations of a mass hanging…

  6. Non linear evolution: revisiting the solution in the saturation region

    NASA Astrophysics Data System (ADS)

    Contreras, Carlos; Levin, Eugene; Meneses, Rodrigo

    2014-10-01

    In this paper we revisit the problem of the solution to Balitsky-Kovchegov equation deeply in the saturation domain. We find that solution has the form given in ref. [23] but it depends on variable and the value of Const is calculated in this paper. We propose the solution for full BFKL kernel at large in the entire kinematic region that satisfies the McLerran-Venugopalan-type [3-7] initial condition.

  7. Relationship Between Solution Shear Viscosity and Density at the Saturation Point

    NASA Technical Reports Server (NTRS)

    Izmailov, Alexander F.; Myerson, Allan S.

    1996-01-01

    Properties of supersaturated solutions such as the density, viscosity, and solute diffusivity are dependent on the solute concentration. The diffusion-boundary-layer equations are derived and solved for the natural convection case with the viscosity and density dependent on the solute concentration. The solution obtained demonstrates that, at the vicinity of the saturation concentration c(sub s), there is a non-trivial dependence of the solution viscosity eta on its density rho: eta(c(sub s)) = eta(rho(sub s)) varies as rho(sub s)(exp 1/2), where rho(sub s) = rho(c(sub s)). This result has been verified in experiments with aqueous solutions of inorganic and organic salts.

  8. Method for preparing salt solutions having desired properties

    DOEpatents

    Ally, Moonis R.; Braunstein, Jerry

    1994-01-01

    The specification discloses a method for preparing salt solutions which exhibit desired thermodynamic properties. The method enables prediction of the value of the thermodynamic properties for single and multiple salt solutions over a wide range of conditions from activity data and constants which are independent of concentration and temperature. A particular application of the invention is in the control of salt solutions in a process to provide a salt solution which exhibits the desired properties.

  9. Electrical conductivity of aqueous solutions of aluminum salts

    NASA Astrophysics Data System (ADS)

    Vila, J.; Rilo, E.; Segade, L.; Cabeza, O.; Varela, L. M.

    2005-03-01

    We present experimental measurements of the specific electrical conductivity (σ) in aqueous solutions of aluminum salts at different temperatures, covering all salt concentrations from saturation to infinite dilution. The salts employed were AlCl3 , AlBr3 , AlI3 , and Al(NO3)3 , which present a 1:3 relationship between the electrical charges of anion and cation. In addition, we have measured the density in all ranges of concentrations of the four aqueous electrolyte solutions at 298.15K . The measured densities show an almost linear behavior with concentration, and we have fitted it to a second order polynomial with very high degree of approximation. The measurement of the specific conductivity at constant temperature reveals the existence of maxima in the conductivity vs concentration curves at molar concentrations around 1.5M for the three halide solutions studied, and at approximately 2M for the nitrate. We present a theoretical foundation for the existence of these maxima, based on the classical Debye-Hückel-Onsager hydrodynamic mean-field framework for electrical transport and its high concentration extensions, and also a brief consideration of ionic frictional coefficients using mode-coupling theory. We also found that the calculated values of the equivalent conductance vary in an approximately linear way with the square root of the concentration at concentrations as high as those where the maximum of σ appears. Finally, and for completeness, we have measured the temperature dependence of the electrical conductivity at selected concentrations from 283to353K , and performed a fit to an exponential equation of the Vogel-Fulcher-Tamman type. The values of the calculated temperatures of null mobility of the four salts are reported.

  10. SOLUTION MINING IN SALT DOMES OF THE GULF COAST EMBAYMENT

    SciTech Connect

    Griswold, G. B.

    1981-02-01

    Following a description of salt resources in the salt domes of the gulf coast embayment, mining, particularly solution mining, is described. A scenario is constructed which could lead to release of radioactive waste stored in a salt dome via inadvertent solution mining and the consequences of this scenario are analyzed.

  11. Solubility of pllutonium in alkaline salt solutions

    SciTech Connect

    Hobbs, D.T.; Edwards, T.B.

    1993-02-26

    Plutonium solubility data from several studies have been evaluated. For each data set, a predictive model has been developed where appropriate. In addition, a statistical model and corresponding prediction intervals for plutonium solubility as a quadratic function of the hydroxide concentration have been developed. Because of the wide range of solution compositions, the solubility of plutonium can vary by as much as three orders of magnitude for any given hydroxide concentration and still remain within the prediction interval. Any nuclear safety assessments that depend on the maximum amount of plutonium dissolved in alkaline salt solutions should use concentrations at least as great as the upper prediction limits developed in this study. To increase the confidence in the prediction model, it is recommended that additional solubility tests be conducted at low hydroxide concentrations and with all of the other solution components involved. To validate the model for application to actual waste solutions, it is recommended that the plutonium solubilities in actual waste solutions be determined and compared to the values predicted by the quadratic model.

  12. Ion aggregation in high salt solutions. III. Computational vibrational spectroscopy of HDO in aqueous salt solutions

    SciTech Connect

    Choi, Jun-Ho; Lim, Sohee; Chon, Bonghwan; Cho, Minhaeng; Kim, Heejae; Kim, Seongheun

    2015-05-28

    The vibrational frequency, frequency fluctuation dynamics, and transition dipole moment of the O—D stretch mode of HDO molecule in aqueous solutions are strongly dependent on its local electrostatic environment and hydrogen-bond network structure. Therefore, the time-resolved vibrational spectroscopy the O—D stretch mode has been particularly used to investigate specific ion effects on water structure. Despite prolonged efforts to understand the interplay of O—D vibrational dynamics with local water hydrogen-bond network and ion aggregate structures in high salt solutions, still there exists a gap between theory and experiment due to a lack of quantitative model for accurately describing O—D stretch frequency in high salt solutions. To fill this gap, we have performed numerical simulations of Raman scattering and IR absorption spectra of the O—D stretch mode of HDO in highly concentrated NaCl and KSCN solutions and compared them with experimental results. Carrying out extensive quantum chemistry calculations on not only water clusters but also ion-water clusters, we first developed a distributed vibrational solvatochromic charge model for the O—D stretch mode in aqueous salt solutions. Furthermore, the non-Condon effect on the vibrational transition dipole moment of the O—D stretch mode was fully taken into consideration with the charge response kernel that is non-local polarizability density. From the fluctuating O—D stretch mode frequencies and transition dipole vectors obtained from the molecular dynamics simulations, the O—D stretch Raman scattering and IR absorption spectra of HDO in salt solutions could be calculated. The polarization effect on the transition dipole vector of the O—D stretch mode is shown to be important and the asymmetric line shapes of the O—D stretch Raman scattering and IR absorption spectra of HDO especially in highly concentrated NaCl and KSCN solutions are in quantitative agreement with experimental results. We

  13. Ion aggregation in high salt solutions. III. Computational vibrational spectroscopy of HDO in aqueous salt solutions.

    PubMed

    Choi, Jun-Ho; Kim, Heejae; Kim, Seongheun; Lim, Sohee; Chon, Bonghwan; Cho, Minhaeng

    2015-05-28

    The vibrational frequency, frequency fluctuation dynamics, and transition dipole moment of the O-D stretch mode of HDO molecule in aqueous solutions are strongly dependent on its local electrostatic environment and hydrogen-bond network structure. Therefore, the time-resolved vibrational spectroscopy the O-D stretch mode has been particularly used to investigate specific ion effects on water structure. Despite prolonged efforts to understand the interplay of O-D vibrational dynamics with local water hydrogen-bond network and ion aggregate structures in high salt solutions, still there exists a gap between theory and experiment due to a lack of quantitative model for accurately describing O-D stretch frequency in high salt solutions. To fill this gap, we have performed numerical simulations of Raman scattering and IR absorption spectra of the O-D stretch mode of HDO in highly concentrated NaCl and KSCN solutions and compared them with experimental results. Carrying out extensive quantum chemistry calculations on not only water clusters but also ion-water clusters, we first developed a distributed vibrational solvatochromic charge model for the O-D stretch mode in aqueous salt solutions. Furthermore, the non-Condon effect on the vibrational transition dipole moment of the O-D stretch mode was fully taken into consideration with the charge response kernel that is non-local polarizability density. From the fluctuating O-D stretch mode frequencies and transition dipole vectors obtained from the molecular dynamics simulations, the O-D stretch Raman scattering and IR absorption spectra of HDO in salt solutions could be calculated. The polarization effect on the transition dipole vector of the O-D stretch mode is shown to be important and the asymmetric line shapes of the O-D stretch Raman scattering and IR absorption spectra of HDO especially in highly concentrated NaCl and KSCN solutions are in quantitative agreement with experimental results. We anticipate that this

  14. Effect of solution saturation state and temperature on diopside dissolution

    SciTech Connect

    Dixit, S; Carroll, S A

    2007-03-23

    Steady-state dissolution rates of diopside are measured as a function of solution saturation state using a titanium flow-through reactor at pH 7.5 and temperature ranging from 125 to 175 C. Diopside dissolved stoichiometrically under all experimental conditions and rates were not dependent on sample history. At each temperature, rates continuously decreased by two orders of magnitude as equilibrium was approached and did not exhibit a dissolution plateau of constant rates at high degrees of undersaturation. The variation of diopside dissolution rates with solution saturation can be described equally well with a ion exchange model based on transition state theory or pit nucleation model based on crystal growth/dissolution theory from 125 to 175 C. At 175 C, both models over predict dissolution rates by two orders of magnitude indicating that a secondary phase precipitated in the experiments. The ion exchange model assumes the formation of a Si-rich, Mg-deficient precursor complex. Lack of dependence of rates on steady-state aqueous calcium concentration supports the formation of such a complex, which is formed by exchange of protons for magnesium ions at the surface.

  15. [Structure and Activity of Fungal Lipases in Bile Salt Solutions].

    PubMed

    Bogdanova, L R; Bakirova, D R; Valiullina, Yu A; Idiyatullin, B Z; Faizullin, D A; Zueva, O S; Zuev, Yu F

    2016-01-01

    The changes in structure and catalytic properties of fungal lipases (Candida rugosa, Rhizomucor miehei, Mucor javanicus) were investigated in micellar solutions of bile salts that differ in hydrophilic-lypophilic balance and reaction medium properties. The methods of circular dichroism and tryptophan fluorescence were applied to estimate the changes in peptide structure within complexes with bile salt micelles. Bile salts do not exert a significant influence on the structure of the enzymes under study: in Rh. miehei and M. javanicus lipases the alpha helix content slightly decreased, the influence of bile salts on the C. rugosa structure was not revealed. Despite negligible structural modifications in the enzymes, in bile salt solutions a considerable change in their catalytic properties was observed: an abrupt decrease in catalytic effectiveness. Substrate-bile salts micelles complex formation was demonstrated by the NMR self-diffusion method. The model of a regulation of fungal lipase activity was proposed. PMID:27192825

  16. Surface viscoelasticity of concentrated salt solutions: specific ion effects.

    PubMed

    Safouane, Mahassine; Langevin, Dominique

    2009-01-12

    Herein, we study the viscoelastic response of concentrated salt solutions using surface waves excited by electrocapillarity. We show that the hydrodynamic behaviour of the solutions is similar to that of water at concentrations up to 2 m-well above the concentration C*, at which inhibition of bubble coalescence occurs in these solutions. This result excludes the occurrence of changes in the slip conditions at C*, postulated to explain this inhibition. Our study is carried out on salts that both increase and decrease the surface tension. We observe that the salt that decreases the tension does not change the surface behaviour at all, whereas the other two salts essentially produce negative contributions to the surface viscoelasticity at very high salt concentrations. The effects observed are quite large and remain to be explained. PMID:19072821

  17. Salt extraction from hydrogen-sulfide scrubber solution using electrodialysis

    SciTech Connect

    Jamaluddin, A.K.M.; Kennedy, M.W.; McManus, D.; Nazarko, T.W.

    1995-05-01

    The buildup of undesirable sulfur compounds (sulfates and thiosulfates) reduces the scrubbing effectiveness of the LO-CAT I autocirculation sulfur recovery process from acid-gas stream. Among various processes, withdrawing and disposing of a portion of the scrubber solution and replacing this blowdown with fresh solution have been the practice in the industry. The application of the electrodialysis system to recycle the blowdown is presented. Experiments were carried out using electrodialysis to separate salts (sulfates and thiosulfates) from the LO-CAT I autocirculation scrubber solution containing organic chelating agents, iron, and various alkali-metal inorganic salts. The results indicated that the electrodialysis was successful in removing 50% of the salts from the scrubber solution with less than 8% loss of organic and 8% loss of carbonates. The fluxes of the undesired salt species were high even at low current densities (200 to 400 A/m{sup 2}).

  18. An empirical correlation between the enthalpy of solution of aqueous salts and their ability to form hydrates

    SciTech Connect

    Pandelov, S.; Werhahn, Jasper C.; Pilles, Bert M.; Xantheas, Sotiris S.; Iglev, H.

    2010-09-30

    The ability of aqueous salt solutions to form hydrates by cooling them at ambient pressure is probed by infrared (IR) spectroscopy by examining the structure of the spectra in the hydrogen-bonding region (3,000 - 3,800 cm-1). A collection of 75 organic and inorganic salts in saturated solutions are examined. We have found a correlation between the enthalpy of solution of the salt and its ability to form a hydrate, namely that the salt’s enthalpy of solution is lower than the standard enthalpy of fusion of ice (6 kJ/mol). This observation can serve as an empirical rule that determines whether a salt will form a hydrate upon cooling from its aqueous solution.

  19. 40 CFR 180.1284 - Ammonium salts of higher fatty acids (C8-C18 saturated; C8-C12 unsaturated); exemption from the...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Ammonium salts of higher fatty acids... Ammonium salts of higher fatty acids (C8-C18 saturated; C8-C12 unsaturated); exemption from the requirement of a tolerance. Ammonium salts of C8-C18 saturated and C8-C12 unsaturated higher fatty acids...

  20. 40 CFR 180.1284 - Ammonium salts of higher fatty acids (C8-C18 saturated; C8-C12 unsaturated); exemption from the...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Ammonium salts of higher fatty acids... Ammonium salts of higher fatty acids (C8-C18 saturated; C8-C12 unsaturated); exemption from the requirement of a tolerance. Ammonium salts of C8-C18 saturated and C8-C12 unsaturated higher fatty acids...

  1. The role of saline solution properties on porous limestone salt weathering by magnesium and sodium sulfates

    NASA Astrophysics Data System (ADS)

    Ruiz-Agudo, E.; Mees, F.; Jacobs, P.; Rodriguez-Navarro, C.

    2007-03-01

    Saline solution properties, viscosity in particular, are shown to be critical in salt weathering associated with sodium and magnesium sulfate crystallization in porous limestone. The crystallization of sodium and magnesium sulfate within a porous limestone has been studied at a macro- and microscale using different techniques, including mercury intrusion porosimetry, environmental scanning microscopy and X-ray computed tomography. Such analysis enabled the visualization of the crystallization process in situ, and at high magnification, yielding critical information as to where and how salts crystallize. Sodium sulfate decahydrate (mirabilite) tends to crystallize in large pores as euhedral micron-sized crystals formed at low supersaturation near to the surface of the stone. In contrast, magnesium sulfate heptahydrate (epsomite) tends to precipitate as anhedral wax-like aggregates formed at high supersaturation and distributed homogeneously throughout the stone pore system filling large and small pores. While the former crystallization behavior resulted in scale formation, the latter led to crack development throughout the bulk stone. Ultimately, the contrasting weathering behavior of the two sulfates is explained by considering differences in flow dynamics of solutions within porous materials that are mainly connected with the higher viscosity of magnesium sulfate saturated solution (7.27 cP) when compared with sodium sulfate saturated solution (1.83 cP). On the basis of such results, new ways to tackle salt weathering, particularly in the field of cultural heritage conservation, are discussed.

  2. Microbial life in the Lake Medee, the largest deep-sea salt-saturated formation

    NASA Astrophysics Data System (ADS)

    Yakimov, Michail M.; La Cono, Violetta; Slepak, Vladlen Z.; La Spada, Gina; Arcadi, Erika; Messina, Enzo; Borghini, Mireno; Monticelli, Luis S.; Rojo, David; Barbas, Coral; Golyshina, Olga V.; Ferrer, Manuel; Golyshin, Peter N.; Giuliano, Laura

    2013-12-01

    Deep-sea hypersaline anoxic lakes (DHALs) of the Eastern Mediterranean represent some of the most hostile environments on our planet. We investigated microbial life in the recently discovered Lake Medee, the largest DHAL found to-date. Medee has two unique features: a complex geobiochemical stratification and an absence of chemolithoautotrophic Epsilonproteobacteria, which usually play the primary role in dark bicarbonate assimilation in DHALs interfaces. Presumably because of these features, Medee is less productive and exhibits reduced diversity of autochthonous prokaryotes in its interior. Indeed, the brine community almost exclusively consists of the members of euryarchaeal MSBL1 and bacterial KB1 candidate divisions. Our experiments utilizing cultivation and [14C]-assimilation, showed that these organisms at least partially rely on reductive cleavage of osmoprotectant glycine betaine and are engaged in trophic cooperation. These findings provide novel insights into how prokaryotic communities can adapt to salt-saturated conditions and sustain active metabolism at the thermodynamic edge of life.

  3. Microbial life in the Lake Medee, the largest deep-sea salt-saturated formation.

    PubMed

    Yakimov, Michail M; La Cono, Violetta; Slepak, Vladlen Z; La Spada, Gina; Arcadi, Erika; Messina, Enzo; Borghini, Mireno; Monticelli, Luis S; Rojo, David; Barbas, Coral; Golyshina, Olga V; Ferrer, Manuel; Golyshin, Peter N; Giuliano, Laura

    2013-01-01

    Deep-sea hypersaline anoxic lakes (DHALs) of the Eastern Mediterranean represent some of the most hostile environments on our planet. We investigated microbial life in the recently discovered Lake Medee, the largest DHAL found to-date. Medee has two unique features: a complex geobiochemical stratification and an absence of chemolithoautotrophic Epsilonproteobacteria, which usually play the primary role in dark bicarbonate assimilation in DHALs interfaces. Presumably because of these features, Medee is less productive and exhibits reduced diversity of autochthonous prokaryotes in its interior. Indeed, the brine community almost exclusively consists of the members of euryarchaeal MSBL1 and bacterial KB1 candidate divisions. Our experiments utilizing cultivation and [(14)C]-assimilation, showed that these organisms at least partially rely on reductive cleavage of osmoprotectant glycine betaine and are engaged in trophic cooperation. These findings provide novel insights into how prokaryotic communities can adapt to salt-saturated conditions and sustain active metabolism at the thermodynamic edge of life. PMID:24352146

  4. Microbial life in the Lake Medee, the largest deep-sea salt-saturated formation

    PubMed Central

    Yakimov, Michail M.; La Cono, Violetta; Slepak, Vladlen Z.; La Spada, Gina; Arcadi, Erika; Messina, Enzo; Borghini, Mireno; Monticelli, Luis S.; Rojo, David; Barbas, Coral; Golyshina, Olga V.; Ferrer, Manuel; Golyshin, Peter N.; Giuliano, Laura

    2013-01-01

    Deep-sea hypersaline anoxic lakes (DHALs) of the Eastern Mediterranean represent some of the most hostile environments on our planet. We investigated microbial life in the recently discovered Lake Medee, the largest DHAL found to-date. Medee has two unique features: a complex geobiochemical stratification and an absence of chemolithoautotrophic Epsilonproteobacteria, which usually play the primary role in dark bicarbonate assimilation in DHALs interfaces. Presumably because of these features, Medee is less productive and exhibits reduced diversity of autochthonous prokaryotes in its interior. Indeed, the brine community almost exclusively consists of the members of euryarchaeal MSBL1 and bacterial KB1 candidate divisions. Our experiments utilizing cultivation and [14C]-assimilation, showed that these organisms at least partially rely on reductive cleavage of osmoprotectant glycine betaine and are engaged in trophic cooperation. These findings provide novel insights into how prokaryotic communities can adapt to salt-saturated conditions and sustain active metabolism at the thermodynamic edge of life. PMID:24352146

  5. Isoconversional Kinetics of Nonisothermal Crystallization of Salts from Solutions.

    PubMed

    Stanford, Victoria L; McCulley, Calla M; Vyazovkin, Sergey

    2016-06-30

    In this study, differential scanning calorimetry (DSC) has been applied to measure the kinetics of nonisothermal crystallization of potassium nitrate and ammonium perchlorate from unsaturated and saturated aqueous solutions. DSC data have been analyzed by an advanced isoconversional method that demonstrates that the process is represented by negative values of the effective activation energy, which varies with the progress of crystallization. The classical nucleation model can be used to predict and understand the experimentally observed variation in the effective activation energy. The saturated and unsaturated solutions have demonstrated distinctly different crystallization kinetics. It is suggested that the unsaturated solutions undergo a change in crystallization mechanism from homogeneous to heterogeneous nucleation. PMID:27305831

  6. METHOD AND APPARATUS FOR CALCINING SALT SOLUTIONS

    DOEpatents

    Lawroski, S.; Jonke, A.A.; Taecker, R.G.

    1961-10-31

    A method is given for converting uranyl nitrate solution into solid UO/ sub 3/, The solution is sprayed horizontally into a fluidized bed of UO/sub 3/ particles at 310 to 350 deg C by a nozzle of the coaxial air jet type at about 26 psig, Under these conditions the desired conversion takes place, and caking in the bed is avoided.

  7. Characterization of Swollen States of Polyelectrolyte Brushes in Salt Solution by Neutron Reflectivity

    NASA Astrophysics Data System (ADS)

    Kobayashi, Motoyasu; Mitamura, Koji; Terada, Masami; Yamada, Norifumi L.; Takahara, Atsushi

    2011-01-01

    Cationic and zwitterionic polyelectrolyte brushes on quartz substrate were synthesized by surface-initiated atom transfer radical polymerization of 2-(methacryloyloxy)-ethyltrimethylammonium chloride (MTAC) and 2-(methacryloyloxy)ethyl phosphorylcholine (MPC). The effects of ionic strength on brush structure are investigated by neutron reflectivity (NR) in NaCl deuterium oxide (D2O) solutions. We observed that poly(MTAC) chains were drastically shrunk at concentrations above 0.1 M NaCl/D2O, which may be the change in charge-screening effect against ions on poly(MTAC). On the other hand, effect of salt concentration on a swollen state of poly(MPC) brush was negligible, even at the high concentration (5.0 M) close to saturation. The behaviour of poly(MPC) in salt aqueous solution is completely different from that of poly(MTAC), which may arise from the unique interaction properties, neutral nature, and hydrated water structure of phosphorylcholine units.

  8. Ice Multiplication by Crystal Growth?Ice growing from the vapor along with tiny amounts of salt solution sheds free ice crystals, at -5C and saturation with respect to liquid water, in quiescent conditions. This is a more appealing explanation for the Hallett-Mossop effect than rime splintering, if it occurs primarily at temperatures near -5C.

    NASA Astrophysics Data System (ADS)

    Knight, C. A.

    2015-12-01

    Ice growing from the vapor, at -5C and liquid water supersaturation, often sheds crystals when it grows along with a small amount of salt solution. The experiments are done with single crystals growing in a temperature-controlled chamber with 5 ml of water in the bottom to maintain and control supersaturation, and the new crystals are detected when they fall into and nucleate the water in the bottom. Crystal growth is initiated by inserting into the growth chamber a pipet tip that contained a few microliters of very dilute salt solution that had been supercooled to -5C and nucleated at the tip. Growth from the vapor ensues, with condensation directly onto ice and onto whatever salt solution is exposed. The results are not completely reproducible, no doubt because the starting details of the exposure of ice and solution is not controllable. However, the shedding of crystals often occurs with starting NaCl concentrations of the order of 0.01 wt. percent, and almost never occurs with "pure" water. The shedding events themselves have not been identified, and an attractive hypothesis for how the shedding of ice occurs has not been found at the time of writing this abstract. By the time of the AGU meeting it is hoped that enough experiments will have been performed in order to say whether this effect is found only near -5C. If it requires a temperature near -5C then it seems to be an attractive explanation of the Hallett-Mossop process. It also, of course, is hoped that an attractive hypothesis for the mechanism of the shedding will have been found.

  9. Properties of alkali-halide salt solutions about polarizable nanoparticle solutes for different ion models

    NASA Astrophysics Data System (ADS)

    Wynveen, Aaron; Bresme, Fernando

    2010-10-01

    We investigate the distributions of various salts about large hydrophobic polarizable solutes in aqueous electrolyte solutions. The solutes are modeled as nanometer-sized cylindrical objects, a scale relevant to biomolecules and nanomaterials, and particularly high aspect ratio nanoparticles. Interactions, including image charge forces arising from the finite polarizability of the solute, between explicit solvent/ions and the solute are computed explicitly using a molecular dynamics simulation methodology we have recently introduced. Comparisons are made between several salt species and different models of the force fields for each ionic component of the salt. We find evidence that both small cations, Li+, and large anions, I-, adsorb at hydrophobic interfaces. Our results indicate that the ion structure about the solute is strongly dependent on the force field investigated, suggesting that ion selectivity is quite sensitive to the respective parameters defining the ion's size and binding energy as well as to the polarizability of the solute.

  10. Preservation of corals in salt-saturated DMSO buffer is superior to ethanol for PCR experiments

    NASA Astrophysics Data System (ADS)

    Gaither, M. R.; Szabó, Z.; Crepeau, M. W.; Bird, C. E.; Toonen, R. J.

    2011-06-01

    Specimen collection is time consuming and expensive, yet few laboratories test preservation methods before setting out on field expeditions. The most common preservation buffer used for coral specimens is >70% EtOH. However, alternatives exist that are less flammable, easier to ship, and are widely used in other taxa. Here, we compare the effects of salt-saturated DMSO (SSD) and EtOH preservation buffers on post-extraction DNA quantity and quality. We found that soft tissue integrity was better maintained and higher quantities of DNA were extracted from EtOH-preserved specimens; however, by all other measures, SSD was a superior preservative to EtOH. Extractions of SSD-preserved specimens resulted in higher molecular weight DNA, higher PCR success, and more efficient amplification than specimens preserved in EtOH. Our results show that SSD is generally a superior preservative to EtOH for specimens destined for PCR studies, but species-specific differences indicate that preservation comparisons should be undertaken before collection and storage of samples.

  11. In situ X-ray microprobe study of salt layers during anodic dissolution of stainless steel in chloride solution

    SciTech Connect

    Isaacs, H.S.; Cho, J.H.; Rivers, M.L.; Sutton, S.R.

    1995-04-01

    Salt layers play an important role in many electrochemical dissolution processes. The composition of salt films formed on austenitic stainless steel have, for the first time, been determined using in situ energy dispersive X-ray fluorescence microanalysis during dissolution in a chloride solution. The electrode was the cross section of a nickel/chromium steel foil sandwiched between plastic sheets. The foil was electrochemically dissolved producing a pit 1.6 mm deep. The electrode configuration simulated localized corrosion with a one-dimensional diffusion geometry. X-ray fluorescence intensities of chromium K{sub {alpha}}, iron K{sub {alpha}}, an nickel K{sub {beta}} energies were measured as the steel/solution interface traversed a 6 {mu}m, polychromatic, high-intensity X-ray beam. Qualitative determinations were made of the composition of the salt layer and the composition of the saturated solution. Salt layer thickness was found to increase with increased applied potentials. The salt layer was found to be rich in iron and depleted in nickel and, particularly, chromium. The effective diffusion coefficients of the dissolved species were determined from the composition of the saturated solution at the interface. Nickel showed the highest and chromium the lowest effective diffusion coefficient.

  12. 9 CFR 96.14 - Uncertified casings; disinfection with saturated brine solution.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... for importation into the United States upon disinfection, may either be disinfected with hydrochloric acid as at present or if preferred may be submerged in a saturated brine solution at a temperature...

  13. 9 CFR 96.14 - Uncertified casings; disinfection with saturated brine solution.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... for importation into the United States upon disinfection, may either be disinfected with hydrochloric acid as at present or if preferred may be submerged in a saturated brine solution at a temperature...

  14. 9 CFR 96.14 - Uncertified casings; disinfection with saturated brine solution.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... for importation into the United States upon disinfection, may either be disinfected with hydrochloric acid as at present or if preferred may be submerged in a saturated brine solution at a temperature...

  15. 9 CFR 96.14 - Uncertified casings; disinfection with saturated brine solution.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... for importation into the United States upon disinfection, may either be disinfected with hydrochloric acid as at present or if preferred may be submerged in a saturated brine solution at a temperature...

  16. Hysteresis of Colloid Retention and Release in Saturated Porous Media During Transients in Solution Chemistry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Saturated packed column and micromodel transport studies wereconducted to gain insightonmechanismsof colloid retention and release under unfavorable attachment conditions. The initial deposition of colloids in porous media was found to be a strongly coupled process that depended on solution chemistr...

  17. Estimation of Retained Crude Oil Associated with Crushed Salt and Salt Cores in the Presence of Near-Saturated Brine

    SciTech Connect

    Grasser, T.W.; Hinkebein, T.E.; O'Hern, T.J.

    1999-02-01

    This paper describes three experiments whose purpose is to determine the amount of retained oil on massive salt surfaces and in crushed salt in the presence of water and brine. These experiments have application to the decommissioning process for the Weeks Island mine. In the first experiment, oil-coated salt cores were immersed in either fresh water or in 85% brine. In the case of both fluids, the oil was completely removed from the cores within several hours. In the second experiment, oil-coated salt pieces were suspended in air and the oil was allowed to drain. The weight of retained oil clinging to the salt was determined. This experiment was used to estimate the total amount of oil clinging to the roofs of the mine. The total amount of oil clinging to the roofs of the mine is estimated to be between 240 and 400 m3 (1500 and 2500 BBL). In the third experiment, a pan of oil-soaked crushed salt was immersed in 85% brine, and oil removal from the salt was monitored as a function of time. At the start of the experiment, prior to immersion, 16% of the bulk volume of the crushed salt was determined to be interstitial oil. After the pan of crushed salt was immersed in 85% brine, 80% of the oil, which had been in the interstitial spaces of the crushed salt, immediately floated to the surface of the brine. This oil was not bound and was immediately released. During the next 380 hours, oil continued to separate from the salt and the rate of transfer was governed by a mass-transfer rate limitation.

  18. Salt Effects on Surface Tethered Peptides in Solution

    PubMed Central

    Feng, Jun; Wong, Ka-Yiu; Lynch, Gillian C.; Gao, Xiaolian; Pettitt, B. Montgomery

    2009-01-01

    The capability to manipulate proteins/peptide fragments at liquid-solid interfaces has led to tremendous applications in detectors and biotechnology. Therefore, understanding the detailed molecular behavior of proteins and peptides tethered on a hard material surface is an interesting and important topic. The inhomogeneity presented by surfaces as well as ions in the solution plays an important role in the thermodynamics and kinetics of the tethered proteins. In this study, we perform a series of molecular dynamics simulations of a pentapeptide RHSVV, a p53 epitope, tethered on a prepared microarray surface in various salt concentrations (0 M, 0.14 M, 0.5 M, and 1M NaCl), as well as free in ionic solution (0M, 0.5M, and 1M). The conformational space the tethered peptide visits largely overlaps with the free peptide in solution. However, surface tethering as well as the salt concentration changes both the thermodynamics and kinetics of the peptide. Frequent conformational changes are observed during the simulations, and tend to be slowed down by both increasing the salt concentration and surface tethering. The local composition of ions at different salt concentrations is also compared between the tethered and free peptide. PMID:19548651

  19. Ionic conductivity of dual-phase polymer electrolytes comprised of NBR/SBR latex films swollen with lithium salt solutions

    SciTech Connect

    Matsumoto, Morihiko; Ichino, Toshihiro; Rutt, J.S.; Nishi, Shiro . NTT Interdisciplinary Research Lab.)

    1994-08-01

    Dual-phase polymer electrolytes (DPE) with high ionic conductivity and good mechanical strength were prepared by swelling poly(acrylonitrile-co-butadiene) rubber (NBR) and poly(styrene-co-butadiene) rubber (SBR) mixed latex films with lithium salt solutions (e.g., 1M LiClO[sub 4]/[gamma]-butyrolactone). The latex films retain particle morphology in the solid state. The NBR phase (formed from fused NBR latex particles) is polar and is impregnated selectively with polar lithium salt solutions, yielding ion-conductive channels, whereas the SBR phase (formed from fused SBR latex particles) is nonpolar and is not impregnated, providing a mechanically supportive matrix. The ionic conductivity of the DPE increased dramatically with increasing content of lithium salt solution, and higher amounts of solution were imbibed with increasing content of NBR relative to SBR. Several factors which affect the ionic conductivity of this system were examined, and the highest ionic conductivity (>10[sup [minus]3] S/cm) was obtained when either an NBR/SBR 70/30 (w/w) or a 50/50 (w/w) latex film was saturated with 1M LiClO[sub 4]/[gamma]-BL solution or 1M LiClO[sub 4]/[gamma]-BL/DME solution. Ion-conductive behavior changed critically with increasing lithium salt solution uptake. At low levels of lithium salt solution uptake, evidence suggested that ionic conductivity of the absorbed lithium salt solution was strongly influenced by the presence of the NBR in the ion-conductive channel, but at higher levels, the effects of the NBR were reduced and free'' lithium salt solution was present.

  20. Arsenophilic Bacterial Processes in Searles Lake: A Salt-saturated, Arsenic-rich, Alkaline Soda Lake.

    NASA Astrophysics Data System (ADS)

    Oremland, R. S.; Kulp, T. R.; Hoeft, S. E.; Miller, L. G.; Swizer Blum, J.; Stolz, J. F.

    2005-12-01

    Searles Lake, located in the Mojave Desert of California, is essentially a chemically-similar, concentrated version of Mono Lake, but having a much higher salinity (e.g., 340 vs. 90 g/L) and a greater dissolved inorganic arsenic content in its brine (e.g., 3.9 vs. 0.2 mM). The source of all this arsenic ultimately comes from hydrothermal spring inputs, thereby underscoring the importance of volcanic and fluvial processes in transporting this toxic element into these closed basin lakes. Nonetheless, the presence of microbial activities with regard to respiration of arsenate oxyanions under anaerobic conditions and the oxidation of arsenite oxyanions under aerobic conditions can be inferred from porewater profiles taken from handcores retrieved beneath Searles Lake's salt crust. Sediment slurry incubations confirmed biological arsenate respiration and arsenite oxidation, with the former processes notably enhanced by provision of the inorganic electron donor sulfide or H2. Hence, arsenic-linked chemo-autotrophy appears to be an important means of carbon fixation in this system. Subsequent efforts using 73As-arsenate as radiotracer detected dissimilatory arsenate reduction activity down the length of the core, but we were unable to detect any evidence for sulfate-reduction using 35S-sulfate. An extremely halophilic anaerobic bacterium of the order Haloanaerobiales [strain SLAS-1] was isolated from the sediments that grew via arsenate respiration using lactate or sulfide as its electron donors. These results show that, unlike sulfate-reduction, arsenic metabolism (i.e., both oxidation of arsenite and dissimilatory reduction of arsenate) is operative and even vigorous under the extreme conditions of salt-saturation and high pH. The occurrence of arsenophilic microbial processes in Searles Lake is relevant to the search for extant or extinct microbial life on Mars. It is evident from surface imagery that Mars had past episodes of volcanism, fluvial transport, and most

  1. Photoionization of Sodium Salt Solutions in a Liquid Jet

    SciTech Connect

    Grieves, G. A.; Petrik, Nikolay G.; Herring-Captain, J.; Olanrewaju, B.; Aleksandrov, A.; Tonkyn, Russell G.; Barlow, Stephan E.; Kimmel, Gregory A.; Orlando, Thomas M.

    2008-06-05

    A liquid microjet was employed to examine the gas/liquid interface of aqueous sodium halide (Na+X-, X=Cl, Br, I) salt solutions. Laser excitation at 193 nm produced and removed cations of the form H+(H2O)n and Na+(H2O)m from liquid jet surfaces containing either NaCl, NaBr or NaI. The protonated water cluster yield varied inversely with increasing salt concentration, while the solvated sodium ion cluster yield varied by anion type. The distribution of H+(H2O)n at low salt concentration is identical to that observed from low-energy electron irradiated amorphous ice and the production of these clusters can be accounted for using a localized ionization/Coulomb expulsion model. Production of Na+(H2O)m is not accounted for by this model but requires ionization of solvation shell waters and a contact ion/Coulomb expulsion mechanism. The reduced yields of Na+(H2O)m from high concentration (10-2 and 10-1 M) NaBr and NaI solutions indicate a propensity for Br- and I- at the solution surfaces and interfaces. This is supported by the observation of multiphoton induced production and desorption of Br+ and I+ from the 10-2 and 10-1 M solution surfaces.

  2. CRITICALITY SAFETY OF PROCESSING SALT SOLUTION AT SRS

    SciTech Connect

    Stephens, K; Davoud Eghbali, D; Michelle Abney, M

    2008-01-15

    High level radioactive liquid waste generated as a result of the production of nuclear material for the United States defense program at the Savannah River Site has been stored as 36 million gallons in underground tanks. About ten percent of the waste volume is sludge, composed of insoluble metal hydroxides primarily hydroxides of Mn, Fe, Al, Hg, and most radionuclides including fission products. The remaining ninety percent of the waste volume is saltcake, composed of primarily sodium (nitrites, nitrates, and aluminates) and hydroxides. Saltcakes account for 30% of the radioactivity while the sludge accounts for 70% of the radioactivity. A pilot plant salt disposition processing system has been designed at the Savannah River Site for interim processing of salt solution and is composed of two facilities: the Actinide Removal Process Facility (ARPF) and the Modular Caustic Side Solvent Extraction Unit (MCU). Data from the pilot plant salt processing system will be used for future processing salt at a much higher rate in a new salt processing facility. Saltcake contains significant amounts of actinides, and other long-lived radioactive nuclides such as strontium and cesium that must be extracted prior to disposal as low level waste. The extracted radioactive nuclides will be mixed with the sludge from waste tanks and vitrified in another facility. Because of the presence of highly enriched uranium in the saltcake, there is a criticality concern associated with concentration and/or accumulation of fissionable material in the ARP and MCU.

  3. Fabrication of CPA Salt Pill with Circulating Solution Method

    NASA Astrophysics Data System (ADS)

    Hoshino, A.; Tokoi, K.; Ishisaki, Y.; Shinozaki, K.; McCammon, D.

    2008-05-01

    We report results on fabrication of a Chromium Potassium Alum (CPA) salt pill. CPA is a typical paramagnetic salt used as refrigerant of Adiabatic Demagnetization Refrigerator (ADR) because of its low Curie point, 4 11 mK. We made an test model of CPA salt pill by fast crystallizing method, namely circulating solution between 36°C and 15°C. The crystallizing rate was 0.5 g h-1, and 40 g of CPA crystal was obtained inside a stainless steel cylinder equipped with 160 copper wires. The cooling test was operated utilizing a commercial ADR system. We attached three thermometers and four heaters to the salt pill, in order to measure thermal conductance among different parts of the pill. It is confirmed that our salt pill was cooled down from B/ T=4 T/2 K to 64 mK at zero magnetic field. We suspect the cause of limiting the cooling temperature in the present level to be the dehydration of CPA, non-uniformity of magnetic field, and stainless steel of the pill which has large heat capacity below 0.1 K.

  4. Numerical Investigations of Vadose Zone Transport of Saturated Sodium Thiosulfate Solutions

    NASA Astrophysics Data System (ADS)

    White, M. D.; Ward, A. L.

    2001-12-01

    Compared with water, hypersaline liquid wastes ([NaNO3] > 10 N) from the reduction-oxidation (REDOX) process at the Hanford site have elevated viscosity (μ > 1.2 cP), density (ρ > 1.4 gm/cm3), and surface tension (σ > 100 dyn/cm). Such liquids have infiltrated into the vadose zone at Hanford from leaking underground storage tanks. The migration behavior of saturated or hypersaline salt solutions through unsaturated soils is largely unknown. Laboratory tests with tank-waste simulants suggest that the elevated density, viscosity, and surface tension properties of these liquids can influence the wetting front behavior, altering its shape and migration rate. Conditions under which these mechanisms are active in the field and the extent to which they contribute to transport through the vadose zone are largely unknown, making it impossible to accurately predict the post-leak distribution of these fluids in the field. To investigate the effects of fluid properties on subsurface migration of hypersaline saline solutions, numerical simulations were conducted of a field-scale, tank-leak experiment. The field experiments consisted of five 4000-L injections, at a depth of 5 m, of saturated sodium thiosulfate brine (used as a surrogate for REDOX type wastes) over a 5-week period, followed by three 4000-L injections of Columbia River water. Pre-test modeling of river water injections at this Hanford field site predicted significant lateral spreading of the moisture plume and were confirmed by geophysical logging. A series of three-dimensional, multifluid (i.e., aqueous and gas phases) numerical simulations were conducted that systematically considered the effects of elevated density, viscosity, and surface tension, and reduced vapor pressure on vadose-zone transport. Hydrologic properties were determined from cores collected at the field site and calibrated using river-water injection experiments. Isothermal conditions were assumed for the simulations, however, the effects of

  5. Separation behaviors of actinides from rare-earths in molten salt electrorefining using saturated liquid cadmium cathode

    NASA Astrophysics Data System (ADS)

    Kato, Tetsuya; Inoue, Tadashi; Iwai, Takashi; Arai, Yasuo

    2006-10-01

    Electrorefining in the molten LiCl-KCl eutectic salt containing actinide (An) and rare-earth (RE) elements was conducted to recover An elements up to 10 wt% into liquid cadmium (Cd) cathode, which is much higher than the solubility of the An elements in liquid Cd at the experimental temperature of 773 K. In the saturated Cd cathode, the An and RE elements were recovered forming a PuCd 11 type compound, MCd 11 (M = An and RE elements). The separation factors of element M against Pu defined as [M/Pu in Cd alloy (cathode)]/[M/Pu in molten salt] were calculated for the saturated Cd cathode including MCd 11. The separation factors were 0.011, 0.044, 0.064, and 0.064 for La, Ce, Pr, and Nd, respectively. These values were a little differed from 0.014, 0.038, 0.044, and 0.043 for the equilibrium unsaturated liquid Cd, respectively. The above slight differences were considered to be caused by the solid phase formation in the saturated Cd cathode and the electrochemical transfer of the An and RE elements in the molten salt.

  6. Scaling Equations for a Biopolymer in Salt Solution

    NASA Astrophysics Data System (ADS)

    Geissler, Erik; Hecht, Anne-Marie; Horkay, Ferenc

    2007-12-01

    The effect of the simultaneous presence of monovalent and divalent cations on the thermodynamics of polyelectrolyte solutions is an incompletely solved problem. In physiological conditions, combinations of these ions affect structure formation in biopolymer systems. Dynamic light scattering measurements of the collective diffusion coefficient D and the osmotic compressibility of semidilute hyaluronan solutions containing different ratios of sodium and calcium ions are compared with simple polyelectrolyte models. Scaling relationships are proposed in terms of polymer concentration and ionic strength J of the added salt. Differences in the effects of sodium and calcium ions are found to be expressed only through J.

  7. SODIUM ALUMINOSILICATE FOULING AND CLEANING OF DECONTAMINATED SALT SOLUTION COALESCERS

    SciTech Connect

    Poirier, M; Thomas Peters, T; Fernando Fondeur, F; Samuel Fink, S

    2008-10-28

    During initial non-radioactive operations at the Modular Caustic Side Solvent Extraction Unit (MCU), the pressure drop across the decontaminated salt solution coalescer reached {approx}10 psi while processing {approx}1250 gallons of salt solution, indicating possible fouling or plugging of the coalescer. An analysis of the feed solution and the 'plugged coalescer' concluded that the plugging was due to sodium aluminosilicate solids. MCU personnel requested Savannah River National Laboratory (SRNL) to investigate the formation of the sodium aluminosilicate solids (NAS) and the impact of the solids on the decontaminated salt solution coalescer. Researchers performed developmental testing of the cleaning protocols with a bench-scale coalescer container 1-inch long segments of a new coalescer element fouled using simulant solution. In addition, the authors obtained a 'plugged' Decontaminated Salt Solution coalescer from non-radioactive testing in the MCU and cleaned it according to the proposed cleaning procedure. Conclusions from this testing include the following: (1) Testing with the bench-scale coalescer showed an increase in pressure drop from solid particles, but the increase was not as large as observed at MCU. (2) Cleaning the bench-scale coalescer with nitric acid reduced the pressure drop and removed a large amount of solid particles (11 g of bayerite if all aluminum is present in that form or 23 g of sodium aluminosilicate if all silicon is present in that form). (3) Based on analysis of the cleaning solutions from bench-scale test, the 'dirt capacity' of a 40 inch coalescer for the NAS solids tested is calculated as 450-950 grams. (4) Cleaning the full-scale coalescer with nitric acid reduced the pressure drop and removed a large amount of solid particles (60 g of aluminum and 5 g of silicon). (5) Piping holdup in the full-scale coalescer system caused the pH to differ from the target value. Comparable hold-up in the facility could lead to less effective

  8. On the uniqueness of the solution of inverse problems in saturation fluorimetry of polyatomic organic compounds

    SciTech Connect

    Kozyreva, O V; Popov, K V

    2000-10-31

    The theoretical and practical uniqueness of the results obtained by the method of nonlinear laser fluorimetry is considered. The theoretical uniqueness of measuring three basic photophysical parameters (the absorption cross section, the excited-state lifetime, and the quantum yield of intersystem crossing) from fluorescence saturation curves is proved rigorously mathematically. The practical uniqueness of the results obtained by this method is proved by the measurements of the absorption cross section and the excited-state lifetime from the calculated curves of fluorescence saturation simulating fluorescence saturation of aqueous solutions of rhodamine 6G, eosin, and Bengal rose dyes. (laser applications and other topics in quantum electronics)

  9. Molecular dynamics study of salt–solution interface: Solubility and surface charge of salt in water

    SciTech Connect

    Kobayashi, Kazuya; Liang, Yunfeng E-mail: matsuoka@earth.kumst.kyoto-u.ac.jp; Matsuoka, Toshifumi E-mail: matsuoka@earth.kumst.kyoto-u.ac.jp; Sakka, Tetsuo

    2014-04-14

    The NaCl salt–solution interface often serves as an example of an uncharged surface. However, recent laser-Doppler electrophoresis has shown some evidence that the NaCl crystal is positively charged in its saturated solution. Using molecular dynamics (MD) simulations, we have investigated the NaCl salt–solution interface system, and calculated the solubility of the salt using the direct method and free energy calculations, which are kinetic and thermodynamic approaches, respectively. The direct method calculation uses a salt–solution combined system. When the system is equilibrated, the concentration in the solution area is the solubility. In the free energy calculation, we separately calculate the chemical potential of NaCl in two systems, the solid and the solution, using thermodynamic integration with MD simulations. When the chemical potential of NaCl in the solution phase is equal to the chemical potential of the solid phase, the concentration of the solution system is the solubility. The advantage of using two different methods is that the computational methods can be mutually verified. We found that a relatively good estimate of the solubility of the system can be obtained through comparison of the two methods. Furthermore, we found using microsecond time-scale MD simulations that the positively charged NaCl surface was induced by a combination of a sodium-rich surface and the orientation of the interfacial water molecules.

  10. Simulation of osmotic pressure in concentrated aqueous salt solutions.

    SciTech Connect

    Luo, Y.; Roux, B.; Univ. of Chicago

    2010-01-01

    Accurate force fields are critical for meaningful simulation studies of highly concentrated electrolytes. The ion models that are widely used in biomolecular simulations do not necessarily reproduce the correct behavior at finite concentrations. In principle, the osmotic pressure is a key thermodynamic property that could be used to test and refine force field parameters for concentrated solutions. Here we describe a novel, simple, and practical method to compute the osmotic pressure directly from molecular dynamics (MD) simulation of concentrated aqueous solutions by introducing an idealized semipermeable membrane. Simple models for Na+, K+, and Cl- are tested and calibrated to accurately reproduce the experimental osmotic pressure at high salt concentration, up to the solubility limit of 4-5 M. The methodology is general and can be extended to any type of solute as well as nonadditive polarizable force fields.

  11. Healthcare Costs Associated with an Adequate Intake of Sugars, Salt and Saturated Fat in Germany: A Health Econometrical Analysis

    PubMed Central

    Meier, Toni; Senftleben, Karolin; Deumelandt, Peter; Christen, Olaf; Riedel, Katja; Langer, Martin

    2015-01-01

    Non-communicable diseases (NCDs) represent not only the major driver for quality-restricted and lost life years; NCDs and their related medical treatment costs also pose a substantial economic burden on healthcare and intra-generational tax distribution systems. The main objective of this study was therefore to quantify the economic burden of unbalanced nutrition in Germany—in particular the effects of an excessive consumption of fat, salt and sugar—and to examine different reduction scenarios on this basis. In this study, the avoidable direct cost savings in the German healthcare system attributable to an adequate intake of saturated fatty acids (SFA), salt and sugar (mono- & disaccharides, MDS) were calculated. To this end, disease-specific healthcare cost data from the official Federal Health Monitoring for the years 2002–2008 and disease-related risk factors, obtained by thoroughly searching the literature, were used. A total of 22 clinical endpoints with 48 risk-outcome pairs were considered. Direct healthcare costs attributable to an unbalanced intake of fat, salt and sugar are calculated to be 16.8 billion EUR (CI95%: 6.3–24.1 billion EUR) in the year 2008, which represents 7% (CI95% 2%-10%) of the total treatment costs in Germany (254 billion EUR). This is equal to 205 EUR per person annually. The excessive consumption of sugar poses the highest burden, at 8.6 billion EUR (CI95%: 3.0–12.1); salt ranks 2nd at 5.3 billion EUR (CI95%: 3.2–7.3) and saturated fat ranks 3rd at 2.9 billion EUR (CI95%: 32 million—4.7 billion). Predicted direct healthcare cost savings by means of a balanced intake of sugars, salt and saturated fat are substantial. However, as this study solely considered direct medical treatment costs regarding an adequate consumption of fat, salt and sugars, the actual societal and economic gains, resulting both from direct and indirect cost savings, may easily exceed 16.8 billion EUR. PMID:26352606

  12. Blending Of Radioactive Salt Solutions In Million Gallon Tanks

    SciTech Connect

    Leishear, Robert A.; Lee, Si Y.; Fowley, Mark D.; Poirier, Michael R.

    2012-12-10

    Research was completed at Savannah River National Laboratory (SRNL) to investigate processes related to the blending of radioactive, liquid waste, salt solutions in 4920 cubic meter, 25.9 meter diameter storage tanks. One process was the blending of large salt solution batches (up to 1135 ? 3028 cubic meters), using submerged centrifugal pumps. A second process was the disturbance of a settled layer of solids, or sludge, on the tank bottom. And a third investigated process was the settling rate of sludge solids if suspended into slurries by the blending pump. To investigate these processes, experiments, CFD models (computational fluid dynamics), and theory were applied. Experiments were performed using simulated, non-radioactive, salt solutions referred to as supernates, and a layer of settled solids referred to as sludge. Blending experiments were performed in a 2.44 meter diameter pilot scale tank, and flow rate measurements and settling tests were performed at both pilot scale and full scale. A summary of the research is presented here to demonstrate the adage that, ?One good experiment fixes a lot of good theory?. Experimental testing was required to benchmark CFD models, or the models would have been incorrectly used. In fact, CFD safety factors were established by this research to predict full-scale blending performance. CFD models were used to determine pump design requirements, predict blending times, and cut costs several million dollars by reducing the number of required blending pumps. This research contributed to DOE missions to permanently close the remaining 47 of 51 SRS waste storage tanks.

  13. Blending of Radioactive Salt Solutions in Million Gallon Tanks - 13002

    SciTech Connect

    Leishear, Robert A.; Lee, Si Y.; Fowley, Mark D.; Poirier, Michael R.

    2013-07-01

    Research was completed at Savannah River National Laboratory (SRNL) to investigate processes related to the blending of radioactive, liquid waste, salt solutions in 4920 cubic meter, 25.9 meter diameter storage tanks. One process was the blending of large salt solution batches (up to 1135 - 3028 cubic meters), using submerged centrifugal pumps. A second process was the disturbance of a settled layer of solids, or sludge, on the tank bottom. And a third investigated process was the settling rate of sludge solids if suspended into slurries by the blending pump. To investigate these processes, experiments, CFD models (computational fluid dynamics), and theory were applied. Experiments were performed using simulated, non-radioactive, salt solutions referred to as supernates, and a layer of settled solids referred to as sludge. Blending experiments were performed in a 2.44 meter diameter pilot scale tank, and flow rate measurements and settling tests were performed at both pilot scale and full scale. A summary of the research is presented here to demonstrate the adage that, 'One good experiment fixes a lot of good theory'. Experimental testing was required to benchmark CFD models, or the models would have been incorrectly used. In fact, CFD safety factors were established by this research to predict full-scale blending performance. CFD models were used to determine pump design requirements, predict blending times, and cut costs several million dollars by reducing the number of required blending pumps. This research contributed to DOE missions to permanently close the remaining 47 of 51 SRS waste storage tanks. (authors)

  14. Surface Potential of DPPC Monolayers on Concentrated Aqueous Salt Solutions.

    PubMed

    Casper, Clayton B; Verreault, Dominique; Adams, Ellen M; Hua, Wei; Allen, Heather C

    2016-03-01

    The presence and exchange of electrical charges on the surfaces of marine aerosols influence their ability to act as cloud condensation nuclei and play a role in thundercloud electrification. Although interactions exist between surface-active inorganic ions and organic compounds, their role in surface charging of marine aerosols is not well understood. In this study, the surface potential of dipalmitoylphosphatidylcholine (DPPC) monolayers, a zwitterionic phospholipid found in the sea surface microlayer, is measured on concentrated (0.3-2.0 M) chloride salt solutions containing marine-relevant cations (Na(+), K(+), Mg(2+), Ca(2+)) to model and elucidate the electrical properties of organic-covered marine aerosols. Monovalent cations show only a weak effect on the surface potential of DPPC monolayers in the condensed phase compared to water. In contrast, Mg(2+) and Ca(2+) increase the surface potential, indicating different cation binding modes and affinities for the PC headgroup. Moreover, it is found that for divalent chloride salt solutions, the PC headgroup and interfacial water molecules make the largest dipolar contribution to the surface potential. This study shows that for equal charge concentrations, divalent cations impact surface potential of DPPC monolayers more strongly than monovalents likely through changes in the PC headgroup orientation induced by their complexation along with the lesser ordering of interfacial water molecules caused by phosphate group charge screening. PMID:26761608

  15. Freezing of snow layers saturated with a calcium chloride aqueous solution

    NASA Astrophysics Data System (ADS)

    Sugawara, M.; Tago, M.; Nozawa, R.; Beer, H.

    2002-09-01

    This paper provides a basic information to control snow layers on roads or runways in order to maintain road safety. The snow saturated with a calcium chloride aqueous solution is initially in the thermodynamic equilibrium at the desired concentration and temperature. Since the snow layer bottom is quickly cooled by maintaining a fixed cooling wall temperature, the aqueous solution in the snow layer will freeze gradually upwards without natural convection in the layer due to the stable density distribution. It is seen that the temperature/concentration and the freezing volume fraction are affected by the cooling wall temperature and the initial concentration in the layer. A simple idealized numerical model predicts well the freezing behavior of the snow layer saturated with the aqueous solution.

  16. Derivation of the macroscopic solute transport equation for homogeneous, saturated, porous media

    SciTech Connect

    Chu, S.Y.; Sposito, G.

    1980-06-01

    The macroscopic transport equation for a conservative solute in a homogeneous, water-saturated porous medium is derived on the basis of a rigorous cumulant expansion applied to the equation of mass balance. The essential physical conept underlying the derivation is that of a local volume-averaged solute velocity which fluctuates on a time scale that is orders of magnitude smaller than its autocorrelation time scale, which, in turn, is much smaller than the time scale of interest in a typical solute transport experiment. This clear separation of the scales is illustrated with representative data on solute transport in homogeneous, water-saturated soils and is employed to justify the truncation of an exact cumulant expansion of the divergence of the volume-averaged solute mass flux density. With the cumulant expansion terminated at first order in the ratio of the solute velocity autocorrelation time to the macroscopic solute transport time interval, an expression for the macroscopic solute mass flux density is produced which is the same as Fick's law extended to porous media. 26 references.

  17. Collapse of sodium polyacrylate chains in calcium salt solutions

    NASA Astrophysics Data System (ADS)

    Schweins, R.; Huber, K.

    The sodium salt of polyacrylic acid (NaPA) precipitates in the presence of Ca^{2+}-ions. This phase behaviour can be represented by a phase diagram where the critical NaPA concentration is plotted versus the critical Ca^{2+} concentration resulting in a straight line as a phase boundary. The location of this phase boundary is influenced by the presence of an inert monovalent salt like NaCl. The present contribution focuses on the coil dimensions of NaPA chains in dilute aqueous solution corresponding to the one phase region of such a phase diagram. A variety of parameters with which the size and shape of the polyelectrolyte chains can be modulated are revealed. Approaching the phase boundary by decreasing the NaPA concentration at a constant Ca^{2+} content leads to a collapse of the NaPA chains. Combined static and dynamic light scattering suggests a compact spherical shape as the final state of this transition, both in 0.1 M NaCl and in 0.01 M NaCl. In the lower NaCl concentration, indication is presented for the existence of a cigar or pearl necklace like intermediate. Most strikingly, the collapsed chains can be reexpanded by increasing the concentration of inert NaCl at constant content of NaPA and Ca^{2+}. Clearly, excessive Na+-ions displace the Ca^{2+}-ions from the NaPA chains.

  18. Salt-enhanced removal of 2-ethyl-1-hexanol from aqueous solutions by adsorption on activated carbon.

    PubMed

    Chang, Ganggang; Bao, Zongbi; Zhang, Zhiguo; Xing, Huabin; Su, Baogen; Yang, Yiwen; Ren, Qilong

    2013-12-15

    2-Ethyl-1-hexanol has extensive industrial applications in solvent extraction, however, in view of its potential pollution to environment, the removal and recovery of 2-ethyl-1-hexanol is considered an essential step toward its sustainable use in the future. In this work, we report the removal of 2-ethyl-1-hexanol from aqueous solutions containing salts in high concentrations by adsorption on a coal-based activated carbon. Adsorption thermodynamics showed that the experimental isotherms were conformed well to the Langmuir equation. Also it was found that inorganic salts, i.e. MgCl2 and CaCl2 in high concentration significantly enhanced the adsorption capacity from 223 mg/g in the deionized water to 277 mg/g in a saline water. This phenomenon of adsorption enhancement could be ascribed to the salt-out effect. Kinetic analysis indicated that adsorption kinetics follows the pseudo-second-order equation and the adsorption rate constants increase with the salt concentration. The dynamic breakthrough volume and adsorbed amount of 2-ethyl-1-hexanol were significantly elevated when the salt is present in the water. The dynamic saturated adsorption amount increased from 218.3mg/g in the deionized water to 309.5mg/g in a salt lake brine. The Tomas model was well applied to predict the breakthrough curves and determine the characteristics parameters of the adsorption column. PMID:24144367

  19. 2D steady-state general solution and fundamental solution for fluid-saturated, orthotropic, poroelastic materials

    NASA Astrophysics Data System (ADS)

    Pan, Li-Hua; Hou, Peng-Fei; Chen, Jia-Yun

    2016-08-01

    The 2D steady-state solutions regarding the expressions of stress and strain for fluid-saturated, orthotropic, poroelastic plane are derived in this paper. For this object, the general solutions of the corresponding governing equation are first obtained and expressed in harmonic functions. Based on these compact general solutions, the suitable harmonic functions with undetermined constants for line fluid source in the interior of infinite poroelastic body and a line fluid source on the surface of semi-infinite poroelastic body are presented, respectively. The fundamental solutions can be obtained by substituting these functions into the general solution, and the undetermined constants can be obtained by the continuous conditions, equilibrium conditions and boundary conditions.

  20. Erosion-corrosion in carbon dioxide saturated systems in presence of sand, inhibitor, oil, and high concentration of salt

    NASA Astrophysics Data System (ADS)

    Hassani, Shokrollah

    Oil and gas production is usually accompanied by formation water which typically contains high levels of chloride. Some effects of chloride concentration on corrosion are not widely known in the literature, and this can result in misleading conclusions. One goal of this research was to contribute to a better understanding of the effects of chloride concentration in CO2 corrosion. Experimental and theoretical studies conducted in the present work have shown that increasing the NaCl concentration in solution has three important effects on corrosion results. First, standard pH meter readings in high NaCl concentration solutions require corrections. Second, increasing the NaCl concentration decreases the CO2 concentration in solution and therefore contributes to a decrease in the corrosion rate. Third, increasing the NaCl concentration increases the solubility of FeCO3 and therefore reduces the likelihood of forming an iron carbonate scale. High NaCl concentration also decreases the sand erosion rate of the metal slightly by increasing the density and viscosity of the liquid. There are two main contributions of this research. The first contribution is the experimental characterization of inhibited erosion-corrosion behavior of mild steel under CO2-saturated conditions with a high salt concentration. Chemical inhibition is one the most important techniques for controlling erosion-corrosion in offshore mild steel pipelines, tubing and pipe fittings in oil and gas industry. The second contribution is the introduction of a new approach for predicting inhibited erosion-corrosion in mild steel pipes including the effects of flow and environmental conditions, sand production, and an oil phase. Sand erosion can decrease the efficiency of corrosion protection systems including iron-carbonate scale formation and chemical inhibition. The need to be able to predict inhibitor performance under sand production conditions is particularly acute when the wells are deep or off

  1. The deliquescence behaviour, solubilities, and densities of aqueous solutions of five methyl- and ethyl-aminium sulphate salts

    NASA Astrophysics Data System (ADS)

    Clegg, Simon L.; Qiu, Chong; Zhang, Renyi

    2013-07-01

    We report measured solubilities of five aminium (i.e., monomethyl, dimethyl, trimethyl, diethyl, and triethyl) sulphate salts in water at 24 °C, and the densities of their aqueous solutions. Using these results, we have converted hygroscopic growth factors determined by Qiu and Zhang (Environ. Sci. Technol. 2012, 46, 4474-4480) to a moles of water per mole of solute basis, and obtained the relationships between concentration and equilibrium relative humidity (water activity) for solutions of the five salts. The results are compared with values predicted using the Extended Aerosol Inorganics Model (E-AIM) of Clegg and co-workers (J. Geophys. Res. 2002, 107, D14, Art. No. 4207). It is assumed in this model that ion and water activities in the solutions are the same as those for aqueous (NH4)2SO4 at the same molality. The experimental and modelled growth factors agree well in all cases, within the uncertainties of the data, which supports this assumption. Equations for the apparent molar volumes of the aminium sulphate salts in aqueous solutions are presented (based upon the measured densities and literature data), and also activity products of the salts in saturated aqueous solutions (based upon the measured solubilities and assumption of similarity with (NH4)2SO4). Simulations of the deliquescence curves of 1:1 and 1:9 mass ratio mixtures of monomethyl and dimethyl aminium sulphate with (NH4)2SO4 are shown to agree well with the measurements. The treatment of amines and aminium salts in the E-AIM model is described.

  2. Polyimide Composites from 'Salt-Like' Solution Precursors

    NASA Technical Reports Server (NTRS)

    Cano, Roberto J.; Hou, Tan H.; Weiser, Erik S.; SaintClair, Terry L.

    2001-01-01

    Four NASA Langley-developed polyimide matrix resins, LaRC(TM)-IA, LaRC(TM)-IAX, LaRC(TM)-8515 and LaRC(TM)-PETI-5, were produced via a 'saltlike' process developed by Unitika Ltd. The salt-like solutions (65% solids in NMP) were prepregged onto Hexcel IM7 carbon fiber using the NASA LaRC multipurpose tape machine. Process parameters were determined and composite panels fabricated. The temperature dependent volatile depletion rates, the thermal crystallization behavior and the resin rheology were characterized. Composite molding cycles were developed which consistently yielded well consolidated, void-free laminated parts. Composite mechanical properties such as the short beam shear strength; the longitudinal and transverse flexural strength and flexural modulus; the longitudinal compression strength and modulus; and the open hole compression strength and compression after impact strength were measured at room temperature and elevated temperatures. The processing characteristics and the composite mechanical properties of the four intermediate modulus carbon fiber/polyimide matrix composites were compared to existing data on the same polyimide resin systems and IM7 carbon fiber manufactured via poly(amide acid) solutions (30-35% solids in NMP). This work studies the effects of varying the synthetic route on the processing and mechanical properties of the polyimide composites.

  3. The effect of divalent salt in chondroitin sulfate solutions

    NASA Astrophysics Data System (ADS)

    Aranghel, D.; Badita, C. R.; Radulescu, A.; Moldovan, L.; Craciunescu, O.; Balasoiu, M.

    2016-03-01

    Chondroitin-4 sulfate (CS4) is the main glycosaminoglycan extracted from bovine trachea. CS4 play an important role in osteoarthritis treatment, anticoagulant activity, reduces the degradation of cartilage matrix components, reduces necrosis and apoptosis of chondrocytes and reduces the activity of collagenase. Chondroitin sulfate is also responsible for proteoglycans degradation. Chondroitin sulfate can bind calcium ions with different affinities, depending on their sulfation position. The purpose of this study was to determine the structural properties and the influence of Ca2+ cations. We carried out measurements on CS4 solutions and mixtures of liquid CS4 with Ca2+ by Small-Angle Neutron Scattering (SANS). CS4 have a mass fractal behavior and the addition of a salt (CaCl2) in CS4 solutions generates the appearance of a correlation peak due to local ordering between adjacent chains with inter-chain distances between 483 Å and 233 Å for a calcium concentration of 0.01% w/w.

  4. The Surface Structure of Concentrated Aqueous salt Solutions

    SciTech Connect

    Sloutskin,E.; Baumert, J.; Ocko, B.; Kuzmenko, I.; Checco, A.; Tamam, L.; Ofer, E.; Gog, T.; Deutsch, M.

    2007-01-01

    The surface-normal electron density profile {rho}{sub s}(z) of concentrated aqueous salt solutions of RbBr, CsCl, LiBr, RbCl, and SrCl{sub 2} was determined by x-ray reflectivity (XR). For all but RbBr and SrCl{sub 2} {rho}{sub s}(z) increases monotonically with depth z from {rho}{sub s}(z)=0 in the vapor (z<0) to {rho}{sub s}(z) = {rho}{sub b} of the bulk (z>0) over a width of a few angstroms. The width is commensurate with the expected interface broadening by thermally excited capillary waves. Anomalous (resonant) XR of RbBr reveals a depletion at the surface of Br{sup -} ions to a depth of {approx}10 A. For SrCl{sub 2}, the observed {rho}{sub s}(z)>{rho}{sub b} may imply a similar surface depletion of Cl{sup -} ions to a depth of a few angstroms. However, as the deviations of the XRs of RbBr and SrCl{sub 2} from those of the other solutions are small, the evidence for a different ion composition in the surface and the bulk is not strongly conclusive. Overall, these results contrast earlier theoretical and simulational results and nonstructural measurements, where significant surface layering of alternate, oppositely charged, ions is concluded.

  5. Model of a wedge-electrode corona discharge under saturation: Exact solutions

    NASA Astrophysics Data System (ADS)

    Boltachev, G. Sh.; Zubarev, N. M.; Zubareva, O. V.

    2014-03-01

    Analytical solutions for the distributions of the electric field potential and electric charge density are derived for the outer region of a steady-state unipolar corona discharge from an ideal wedge-shaped electrode under the conditions of space-charge-limited current. Two situations are considered: a corona is initiated only from the edge of the wedge and from the entire surface of the electrode. In the former case, general solutions are obtained by sewing together exact cylindrically symmetric solutions in the drift space and plane symmetric solutions in space-charge-free regions. In the latter case, the field distribution near the edge turns out to be self-similar, i.e., invariant under extensions in the cross-sectional plane of the wedge, with the center at the top of the wedge. For both models, the dependences of the saturation current per edge's unit length on the apex angle and applied potential difference are obtained.

  6. Modeling variably saturated subsurface solute transport with MODFLOW-UZF and MT3DMS

    USGS Publications Warehouse

    Morway, Eric D.; Niswonger, Richard G.; Langevin, Christian D.; Bailey, Ryan T.; Healy, Richard W.

    2013-01-01

    The MT3DMS groundwater solute transport model was modified to simulate solute transport in the unsaturated zone by incorporating the unsaturated-zone flow (UZF1) package developed for MODFLOW. The modified MT3DMS code uses a volume-averaged approach in which Lagrangian-based UZF1 fluid fluxes and storage changes are mapped onto a fixed grid. Referred to as UZF-MT3DMS, the linked model was tested against published benchmarks solved analytically as well as against other published codes, most frequently the U.S. Geological Survey's Variably-Saturated Two-Dimensional Flow and Transport Model. Results from a suite of test cases demonstrate that the modified code accurately simulates solute advection, dispersion, and reaction in the unsaturated zone. Two- and three-dimensional simulations also were investigated to ensure unsaturated-saturated zone interaction was simulated correctly. Because the UZF1 solution is analytical, large-scale flow and transport investigations can be performed free from the computational and data burdens required by numerical solutions to Richards' equation. Results demonstrate that significant simulation runtime savings can be achieved with UZF-MT3DMS, an important development when hundreds or thousands of model runs are required during parameter estimation and uncertainty analysis. Three-dimensional variably saturated flow and transport simulations revealed UZF-MT3DMS to have runtimes that are less than one tenth of the time required by models that rely on Richards' equation. Given its accuracy and efficiency, and the wide-spread use of both MODFLOW and MT3DMS, the added capability of unsaturated-zone transport in this familiar modeling framework stands to benefit a broad user-ship.

  7. Modeling variably saturated subsurface solute transport with MODFLOW-UZF and MT3DMS.

    PubMed

    Morway, Eric D; Niswonger, Richard G; Langevin, Christian D; Bailey, Ryan T; Healy, Richard W

    2013-03-01

    The MT3DMS groundwater solute transport model was modified to simulate solute transport in the unsaturated zone by incorporating the unsaturated-zone flow (UZF1) package developed for MODFLOW. The modified MT3DMS code uses a volume-averaged approach in which Lagrangian-based UZF1 fluid fluxes and storage changes are mapped onto a fixed grid. Referred to as UZF-MT3DMS, the linked model was tested against published benchmarks solved analytically as well as against other published codes, most frequently the U.S. Geological Survey's Variably-Saturated Two-Dimensional Flow and Transport Model. Results from a suite of test cases demonstrate that the modified code accurately simulates solute advection, dispersion, and reaction in the unsaturated zone. Two- and three-dimensional simulations also were investigated to ensure unsaturated-saturated zone interaction was simulated correctly. Because the UZF1 solution is analytical, large-scale flow and transport investigations can be performed free from the computational and data burdens required by numerical solutions to Richards' equation. Results demonstrate that significant simulation runtime savings can be achieved with UZF-MT3DMS, an important development when hundreds or thousands of model runs are required during parameter estimation and uncertainty analysis. Three-dimensional variably saturated flow and transport simulations revealed UZF-MT3DMS to have runtimes that are less than one tenth of the time required by models that rely on Richards' equation. Given its accuracy and efficiency, and the wide-spread use of both MODFLOW and MT3DMS, the added capability of unsaturated-zone transport in this familiar modeling framework stands to benefit a broad user-ship. PMID:22834908

  8. Comparison of finite difference and finite element solutions to the variably saturated flow equation

    NASA Astrophysics Data System (ADS)

    Simpson, M. J.; Clement, T. P.

    2003-01-01

    Numerical solutions to the equation governing variably saturated flow are usually obtained using either the finite difference (FD) method or the finite element (FE) method. A detailed comparison of these methods shows that the main difference between them is in how the numerical schemes spatially average the variation of material properties. Further differences are also observed in the way that flux boundaries are represented in FE and FD methods. A modified finite element (MFE) algorithm is used to explore the significance of these differences. The MFE algorithm enables a direct comparison with a typical FD solution scheme, and explicitly demonstrates the differences between FE and FD methods. The MFE algorithm provides an improved approximation to the partial differential equation over the usual FD approach while being computationally simpler to implement than the standard FE solution. One of the main limitations of the MFE algorithm is that the algorithm was developed by imposing several restrictions upon the more general FE solution; however, the MFE is shown to be preferable over the usual FE and FD solutions for some of the test problems considered in this study. The comparison results show that the FE (or MFE) solution can avoid the erroneous results encountered in the FD solution for coarsely discretized problems. The improvement in the FE solution is attributed to the broader hydraulic conductivity averaging and differences in the representation of flux type boundaries.

  9. Oil removal and effects of spilled oil on active microbial communities in close to salt-saturation brines.

    PubMed

    Corsellis, Yannick Y; Krasovec, Marc M; Sylvi, Léa L; Cuny, Philippe P; Militon, Cécile C

    2016-05-01

    Abiotic and biotic processes associated with the degradation of a light petroleum in brines close to the salt-saturation (~31 %) and the effect of labile organic matter (LOM) supply (casaminoacids/citrate; 0.2 and 0.1 % w/v, respectively) were followed during an incubation of 30 days. After 4-week incubation at 40 °C under light/dark cycles, a 24 % of abiotic degradation was observed in untreated brines. The stimulation of native brines community with LOM addition allowed an additional 12.8 % oil attenuation due to biodegradation processes. Successional changes in the active microbial community structure due to the oil contamination (16S rRNA DGGE approach) showed the selection of one phylotype affiliated to Salinibacter and the disappearance of Haloquadratum walsbyi in untreated brines. In LOM-amended microcosms, phylotypes related to Salinibacter, Haloarcula, Haloterrigena and Halorhabdus were selected. An effect of hydrocarbon contamination was only observed in the bacterial community with the inhibition of two dominant proteobacterial phylotypes. This study further confirms that short-term and moderate oil biodegradation is possible in LOM-stimulated brines. Biodegradation should be much more reduced under in situ conditions. Self-cleaning capacities of close to saturation hypersaline lakes appears, therefore very limited compared to non-extreme haline environments. PMID:26955981

  10. Modeling variably saturated multispecies reactive groundwater solute transport with MODFLOW-UZF and RT3D.

    PubMed

    Bailey, Ryan T; Morway, Eric D; Niswonger, Richard G; Gates, Timothy K

    2013-01-01

    A numerical model was developed that is capable of simulating multispecies reactive solute transport in variably saturated porous media. This model consists of a modified version of the reactive transport model RT3D (Reactive Transport in 3 Dimensions) that is linked to the Unsaturated-Zone Flow (UZF1) package and MODFLOW. Referred to as UZF-RT3D, the model is tested against published analytical benchmarks as well as other published contaminant transport models, including HYDRUS-1D, VS2DT, and SUTRA, and the coupled flow and transport modeling system of CATHY and TRAN3D. Comparisons in one-dimensional, two-dimensional, and three-dimensional variably saturated systems are explored. While several test cases are included to verify the correct implementation of variably saturated transport in UZF-RT3D, other cases are included to demonstrate the usefulness of the code in terms of model run-time and handling the reaction kinetics of multiple interacting species in variably saturated subsurface systems. As UZF1 relies on a kinematic-wave approximation for unsaturated flow that neglects the diffusive terms in Richards equation, UZF-RT3D can be used for large-scale aquifer systems for which the UZF1 formulation is reasonable, that is, capillary-pressure gradients can be neglected and soil parameters can be treated as homogeneous. Decreased model run-time and the ability to include site-specific chemical species and chemical reactions make UZF-RT3D an attractive model for efficient simulation of multispecies reactive transport in variably saturated large-scale subsurface systems. PMID:23131109

  11. Modeling variably saturated multispecies reactive groundwater solute transport with MODFLOW-UZF and RT3D

    USGS Publications Warehouse

    Bailey, Ryan T.; Morway, Eric D.; Niswonger, Richard G.; Gates, Timothy K.

    2013-01-01

    A numerical model was developed that is capable of simulating multispecies reactive solute transport in variably saturated porous media. This model consists of a modified version of the reactive transport model RT3D (Reactive Transport in 3 Dimensions) that is linked to the Unsaturated-Zone Flow (UZF1) package and MODFLOW. Referred to as UZF-RT3D, the model is tested against published analytical benchmarks as well as other published contaminant transport models, including HYDRUS-1D, VS2DT, and SUTRA, and the coupled flow and transport modeling system of CATHY and TRAN3D. Comparisons in one-dimensional, two-dimensional, and three-dimensional variably saturated systems are explored. While several test cases are included to verify the correct implementation of variably saturated transport in UZF-RT3D, other cases are included to demonstrate the usefulness of the code in terms of model run-time and handling the reaction kinetics of multiple interacting species in variably saturated subsurface systems. As UZF1 relies on a kinematic-wave approximation for unsaturated flow that neglects the diffusive terms in Richards equation, UZF-RT3D can be used for large-scale aquifer systems for which the UZF1 formulation is reasonable, that is, capillary-pressure gradients can be neglected and soil parameters can be treated as homogeneous. Decreased model run-time and the ability to include site-specific chemical species and chemical reactions make UZF-RT3D an attractive model for efficient simulation of multispecies reactive transport in variably saturated large-scale subsurface systems.

  12. Saturated sodium chloride solution under an external static electric field: A molecular dynamics study

    NASA Astrophysics Data System (ADS)

    Ren, Gan; Wang, Yan-Ting

    2015-12-01

    The behavior of saturated aqueous NaCl solutions under a constant external electric field (E) was studied by molecular dynamics (MD) simulation. Our dynamic MD simulations indicated that the irreversible nucleation process towards crystallization is accelerated by a moderate E but retarded or even prohibited under a stronger E, which can be understood by the competition between self-diffusion and drift motion. The former increases with E, thereby accelerating the nucleation process, whereas the latter pulls oppositely charged ions apart under a stronger E, thereby decelerating nucleation. Additionally, our steady-state MD simulations indicated that a first-order phase transition occurs in saturated solutions at a certain threshold Ec. The magnitude of Ec increases with concentration because larger clusters form more easily when the solution is more concentrated and require a stronger E to dissociate. Project supported by the National Basic Research Program of China (Grant No. 2013CB932804) and the National Natural Science Foundation of China (Grant Nos. 91227115, 11274319, and 11421063).

  13. ISOPAR L Release Rates from Saltstone Using Simulated Salt Solutions

    SciTech Connect

    Bronikowski, M

    2006-02-06

    The Modular Caustic-Side Solvent Extraction (CSSX) Unit (MCU) and the Salt Waste Processing Facility (SWPF) will produce a Deactivated Salt Solution (DSS) that will go to the Saltstone Production Facility (SPF). Recent information indicates that solvent entrainment in the DSS is larger than expected. The main concern is with Isopar{reg_sign} L, the diluent in the solvent mixture, and its flammability in the saltstone vault. If it is assumed that all the Isopar{reg_sign} L is released instantaneously into the vault from the curing grout before each subsequent pour; the Isopar{reg_sign} L in the vault headspace is well mixed; and each pour displaces an equivalent volume of headspace, the allowable concentration of Isopar{reg_sign} L in the DSS sent to SPF has been calculated at approximately 4 ppm. The amount allowed would be higher, if the release from grout were significantly less. The Savannah River National Laboratory was tasked with determining the release of Isopar{reg_sign} L from saltstone prepared with a simulated DSS with Isopar{reg_sign} L concentrations ranging from 50 mg/L to 200 mg/L in the salt fraction and with test temperatures ranging from ambient to 95 C. The results from the curing of the saltstone showed that the Isopar{reg_sign} L release data can be treated as a percentage of initial concentration in the concentration range studied. The majority of the Isopar{reg_sign} L that was released over the test duration was released in the first few days. The release of Isopar{reg_sign} L begins immediately and the rate of release decreases over time. At higher temperatures the immediate release is larger than at lower temperatures. In one test at 95 C essentially all of the Isopar{reg_sign} L was released in three months. Initial curing temperature was found to be very important as slight variations during the first few days affected the final Isopar{reg_sign} L amount released. Short scoping tests at 95 C with solvent containing all components (Isopar

  14. ISOPAR L RELEASE RATES FROM SALTSTONE USING SIMULATED SALT SOLUTIONS

    SciTech Connect

    Zamecnik, J; Michael Bronikowski, M; Alex Cozzi, A; Russell Eibling, R; Charles Nash, C

    2008-07-31

    The Modular Caustic-Side Solvent Extraction (CSSX) Unit (MCU) and the Salt Waste Processing Facility (SWPF) will produce a Decontaminated Salt Solution (DSS) that will go to the Saltstone Production Facility (SPF). Recent information indicates that solvent entrainment in the DSS is larger than expected. The main concern is with Isopar{reg_sign} L, the diluent in the solvent mixture, and its flammability in the saltstone vault. If it is assumed that all the Isopar{reg_sign} L is released instantaneously into the vault from the curing grout before each subsequent pour, the Isopar{reg_sign} L in the vault headspace is well mixed, and each pour displaces an equivalent volume of headspace, the maximum concentration of Isopar{reg_sign} L in the DSS to assure 25% of the lower flammable limit is not exceeded has been determined to be about 4 ppm. The amount allowed would be higher if the release from grout were significantly less. The Savannah River National Laboratory was tasked with determining the release of Isopar{reg_sign} L from saltstone prepared with a simulated DSS with Isopar{reg_sign} L concentrations ranging from 50 to 200 mg/L in the salt fraction and with test temperatures ranging from ambient to 95 C. The results from the curing of the saltstone showed that the amount of Isopar{reg_sign} L released versus time can be treated as a percentage of initial amount present; there was no statistically significant dependence of the release rate on the initial concentration. The majority of the Isopar{reg_sign} L that was released over the test duration was released in the first few days. The release of Isopar{reg_sign} L begins immediately and the rate of release decreases over time. At higher temperatures the immediate release rate is larger than at lower temperatures. Initial curing temperature was found to be very important as slight variations during the first few hours or days had a significant effect on the amount of Isopar{reg_sign} L released. Short scoping

  15. Adsorption of Oil onto API-X100 Pipeline Steel in CO2-Saturated Solutions

    NASA Astrophysics Data System (ADS)

    Eliyan, Faysal Fayez; Alfantazi, Akram

    2013-12-01

    This research explores the validity of Langmuir adsorption theorem in analyzing the natural corrosion inhibition by an aromatic C10H12 compound, in a hydrocarbon fuel, in 1-bar CO2-saturated solutions. The adsorption isotherms were constructed from the efficiencies of inhibition, by 10, 20, and 30 vol pct of the fuel, of the corrosion rates calculated from potentiodynamic polarization measurements, in 2 NaCl g/L solutions at 293 K, 323 K, and 353 K (20 °C, 50 °C, and 80 °C). The corrosion rates increased with temperature, and the hydrocarbon fuel, seemingly showing cathodic-inhibition characteristics, acted less efficiently accordingly; two main results the potentiodynamic polarization, electrochemical impedance spectroscopy and open-circuit measurements, demonstrated agreement on with each other.

  16. A Study of Novel Hexavalent Phosphazene Salts as Draw Solutes in Forward Osmosis

    SciTech Connect

    Mark L. Stone; Aaron D. Wilson; Mason K. Harrup; Frederick F. Stewart

    2013-03-01

    Two novel multi-valent salts based on phosphazene chemistry have been synthesized and characterized as forward osmosis (FO) draw solutes. Commercially obtained hexachlorocyclotriphosphazene was reacted with the sodium salt of 4-ethylhydroxybenzoate to yield hexa(4-ethylcarboxylatophenoxy)phosphazene. Hydrolysis, followed by and neutralization with NaOH or LiOH, of the resulting acidic moieties yielded water soluble sodium and lithium phosphazene salts, respectively. Degrees of dissociation were determined through osmometry over the range of 0.05-0.5 m, giving degrees of 3.08-4.95 per mole, suggesting a high osmotic potential. The Li salt was found to be more ionized in solution than the sodium salt, and this was reflected in FO experiments where the Li salt gave higher initial fluxes (~ 7 L/m2h) as compared to the sodium salt (~6 L/m2h) at identical 0.07 m draw solution concentrations at 30 °C. Longer term experiments revealed no detectable degradation of the salts; however some hydrolysis of the cellulose acetate membrane was observed, presumably due to the pH of the phosphazene salt draw solution (pH = ~8).

  17. The Arsenic Cycle in Searles Lake, California: An Arsenic-Rich, Salt-Saturated Soda Lake: I. Sediment Experiments.

    NASA Astrophysics Data System (ADS)

    Kulp, T. R.; Hoeft, S. E.; Miller, L. G.; Baesman, S. M.; Oremland, R. S.

    2004-12-01

    Searles Lake is a residual playa of what once was the end-member of a series of soda lakes that were connected during the Pleistocene. Brinewaters are saturated (300 g/L), alkaline (pH = 9.8), and rich in arsenic (3.9 mM). Porewater profiles (max. depth = 25 cm.) show the speciation of arsenic changes from arsenate [As(V)] in the slightly oxic (DO = 6.2 uM) surface to predominantly arsenite [As(III)] in the sediments. Porewaters also contained ammonia (0.4 - 1.2 mM), sulfide (0.1 - 0.2 mM), and methane (0.05 - 0.6 uM). Sediment slurries incubated with artificial brinewater (salinity = 346 g/L) demonstrated reduction of As(V) to As(III). The rate of As(V) reduction (40 umol/L/day) increased 50 percent with addition of lactate. Addition of sulfide or hydrogen to slurries stimulated this rate by 2.4- and 4.1-fold, respectively. This suggests that chemoautotrophs are important agents of As(V)-respiration in this system. The rate of As(V)-reduction responded inversely with increased salinity, decreasing from 470 umol/L/day at 50 g/L to 40 umol/L/day at 346 g/L. A similar relationship to salinity was found for methane production. Slurries incubated under aerobic conditions showed a rapid biological oxidization of As(III) (rate = 220 umol/L/day). These results show that a microbiological arsenic cycle occurs in this extreme environment. The anaerobes in this ecosystem, however, seem best adapted to lower salinities. Nonetheless, significant dissimilatory As(V) reduction still occurs at the condition of salt-saturation.

  18. Salt weathering in Egyptian limestone after laboratory simulations with continuous flow of salt solutions at different temperatures

    NASA Astrophysics Data System (ADS)

    Aly, Nevin; Gomez-Heras, Miguel; Hamed, Ayman; Alvarez de Buergo, Monica

    2013-04-01

    weathering in Egyptian limestone after laboratory simulations with continuous flow of salt solutions at different temperatures Nevin Aly Mohamed (1), Miguel Gomez - Heras(2), Ayman Hamed Ahmed (1), and Monica Alvarez de Buergo(2). (1) Faculty of Pet. & Min. Engineering- Suez Canal University, Suez, Egypt, (2) Instituto de Geociencias (CSIC-UCM) Madrid. Spain. Limestone is one of the most frequent building stones in Egypt and is used since the time of ancient Egyptians and salt weathering is one of the main threats to its conservation. Most of the limestone used in historical monuments in Cairo is a biomicrite extracted from the Mid-Eocene Mokattam Group. During this work, cylindrical samples (2.4 cm diameter and approx. 4.8 cm length) were subjected, in a purpose-made simulation chamber, to simulated laboratory weathering tests with fixed salt concentration (10% weight NaCl solution), at different temperatures, which were kept constant throughout each test (10, 20, 30, 40 oC). During each test, salt solutions flowed continuously imbibing samples by capilarity. Humidity within the simulation chamber was reduced using silica gel to keep it low and constant to increase evaporation rate. Temperature, humidity inside the simulation chamber and samples weight were digitally monitored during each test. Results show the advantages of the proposed experimental methodology using a continuous flow of salt solutions and shed light on the effect of temperature on the dynamics of salt crystallization on and within samples. Research funded by mission sector of high education ministry, Egypt and Geomateriales S2009/MAT-1629.

  19. Concentration and precipitation of NaCl and KCl from salt cake leach solutions by electrodialysis

    SciTech Connect

    Sreenivasarao, K; Patsiogiannis, F.; Hryn, J.N.

    1997-02-09

    Electrodialysis was investigated for cost-effective recovery of salt from salt cake leach solutions. (Salt cake is a waste stream generated by the aluminum industry during treatment of aluminum drosses and scrap.) We used a pilot-scale electrodialysis stack of 5 membrane pairs, each with an effective area of 0.02 m{sup 2}. The diluate stream contained synthetic NaCl, KCl,mixtures of NaCl and KCl, and actual salt cake leach solutions (mainly NaCl and KCl, with small amounts of MgCl{sub 2}). We concentrated and precipitated NaCl and KCl salts from the concentrate steam when the initial diluate stream concentration was 21.5 to 28.8 wt% NaCl and KCl. We found that water transferring through the membranes was a significant factor in overall efficiency of salt recovery by electrodialysis.

  20. Testing of stripping columns for the removal of benzene from aqueous radioactive salt solution

    SciTech Connect

    Georgeton, G.K.; Taylor, G.A.; Gaughan, T.P.

    1995-06-27

    Radioactive high level wastes (HLW) generated from production of special nuclear materials at the Savannah River Site (SRS) are held in interim storage in 51 underground, million gallon tanks. Radioactive cesium ({sup 137}Cs) is segregated by evaporation of aqueous waste solution for interim storage in a salt matrix comprised of Na and K salts or in concentrated salt solution. The saltcake will be dissolved and {sup 137}Cs will be separated from the nonradioactive salts in solution in the In-Tank Precipitation (ITP) Process. The cesium will be combined with other radioactive species and glass formers to be melted and poured into stainless steel canisters in the Defense Waste Processing Facility (DWPF). The salt solution remaining after decontamination in the ITP process will be incorporated into grout for disposal at the site`s Saltstone facility. In the ITP facility, sodium tetraphenylborate (STPB) will be added to precipitate the cesium. Potassium in the waste solution also reacts with STPB and precipitates. Due to radiolytic and chemical degradation of the tetraphenylborate (TPB) precipitate, benzene is generated. The benzene dissolves into the decontaminated salt solution (DSS) and into water (WW) used to {open_quotes}wash{close_quotes} the precipitate to lower the soluble salt content of the slurry. Safety and processing requirements for disposal of the DSS and for temporary storage of the WW dictate that the benzene concentration be reduced.

  1. Novel, electrolyte solutions comprising fully inorganic salts with high anodic stability for rechargeable magnesium batteries

    SciTech Connect

    Doe, RE; Han, R; Hwang, J; Gmitter, AJ; Shterenberg, I; Yoo, HD; Pour, N; Aurbach, D

    2014-01-01

    Herein the first inorganic magnesium salt solution capable of highly reversible magnesium electrodeposition is presented. Synthesized by acid-base reaction of MgCl2 and Lewis acidic compounds such as AlCl3, this salt class demonstrates upwards of 99% Coulombic efficiency, deposition overpotential of <200 mV, and anodic stability of 3.1 V.

  2. Location of microseismic swarms induced by salt solution mining

    NASA Astrophysics Data System (ADS)

    Kinscher, J.; Bernard, P.; Contrucci, I.; Mangeney, A.; Piguet, J. P.; Bigarre, P.

    2015-01-01

    Ground failures, caving processes and collapses of large natural or man-made underground cavities can produce significant socio-economic damages and represent a serious risk envisaged by the mine managements and municipalities. In order to improve our understanding of the mechanisms governing such a geohazard and to test the potential of geophysical methods to prevent them, the development and collapse of a salt solution mining cavity was monitored in the Lorraine basin in northeastern France. During the experiment, a huge microseismic data set (˜50 000 event files) was recorded by a local microseismic network. 80 per cent of the data comprised unusual swarming sequences with complex clusters of superimposed microseismic events which could not be processed through standard automatic detection and location routines. Here, we present two probabilistic methods which provide a powerful tool to assess the spatio-temporal characteristics of these swarming sequences in an automatic manner. Both methods take advantage of strong attenuation effects and significantly polarized P-wave energies at higher frequencies (>100 Hz). The first location approach uses simple signal amplitude estimates for different frequency bands, and an attenuation model to constrain the hypocentre locations. The second approach was designed to identify significantly polarized P-wave energies and the associated polarization angles which provide very valuable information on the hypocentre location. Both methods are applied to a microseismic data set recorded during an important step of the development of the cavity, that is, before its collapse. From our results, systematic spatio-temporal epicentre migration trends are observed in the order of seconds to minutes and several tens of meters which are partially associated with cyclic behaviours. In addition, from spatio-temporal distribution of epicentre clusters we observed similar epicentre migration in the order of hours and days. All together, we

  3. Students' Misconceptions in Electrochemistry: Current Flow in Electrolyte Solutions and the Salt Bridge.

    ERIC Educational Resources Information Center

    Sanger, Michael J.; Greenbowe, Thomas J.

    1997-01-01

    Examines students' misconceptions and proposed mechanisms related to current flow in electrolyte solutions and the salt bridge. Confirms reported misconceptions and identifies several new ones. Discusses probable sources of misconceptions and some methods for preventing them. Contains 27 references. (JRH)

  4. Boiling Performance of Antifreeze Solutions in a Saturate Pool Boiling System

    NASA Astrophysics Data System (ADS)

    Matsumura, Kunihito; Kaminaga, Fumito

    Nucleate boiling of binary mixtures is of particular importance in a various industries. The purpose of the present study is to provide experimental data and prediction method for nucleate boiling heat transfer of anti-freeze solutions, Propylene-glycol (PG)/water and Ethylene-glycol (EG)/water. The pool nucleate boiling experiments were carried out under a saturated and atmospheric condition. The platinum wire of 0.3 mm diameter was used as the heating surface. The mole fractions of solutions are varied from 0.85 to 1. It was found that the heat transfer coefficient gradually decreases with increasing fraction of anti-freeze to water. It was also shown that a small addition of propylene-glycol and ethylene-glycol also decreases the CHF value far below that of pure water. It is concluded that the correlation proposed by Fujita for several binary mixtures can well predict the heat transfer coefficients within almost ±5% accuracy for every concentration of present anti-freeze solutions.

  5. Nuclear magnetic resonance in water solutions of inorganic salts in vitreous and liquid states

    SciTech Connect

    Lundin, A. G. Koryavko, N. A.; Chichikov, S. A.

    2013-05-15

    Peculiarities of the behavior of water solutions of inorganic salts at temperatures of {approx}(120-150) K are examined. At these temperatures the solutions are in the vitreous state. At higher temperatures (up to 240 K) the solutions may be in metastable liquid, crystalline, or usual liquid states.

  6. Materials and methods for stabilizing nanoparticles in salt solutions

    DOEpatents

    Robinson, David Bruce; Zuckermann, Ronald; Buffleben, George M.

    2013-06-11

    Sequence-specific polymers are proving to be a powerful approach to assembly and manipulation of matter on the nanometer scale. Ligands that are peptoids, or sequence-specific N-functional glycine oligomers, allow precise and flexible control over the arrangement of binding groups, steric spacers, charge, and other functionality. We have synthesized short peptoids that can prevent the aggregation of gold nanoparticles in high-salt environments including divalent salt, and allow co-adsorption of a single DNA molecule. This degree of precision and versatility is likely to prove essential in bottom-up assembly of nanostructures and in biomedical applications of nanomaterials.

  7. In vitro stability of a highly crystalline hydroxylapatite coating in a saturated citric acid solution.

    PubMed

    Story, B J; Burgess, A V; La, D; Wagner, W R

    1999-01-01

    A novel pressurized hydrothermal post-plasma-spray process has been developed to convert the crystalline non-HA and amorphous components of plasma-sprayed hydroxylapatite coatings back into crystalline HA. The process, known commercially as MP-1, was used to produce coatings comprising approximately 96% crystalline HA. The in vitro solubility of the coating in saturated citric acid solution has been measured to simulate the effect of implant detoxification procedures, which use citric acid as a cleaning medium. The MP-1 coating solubility in saturated citric acid solution (pH = 1) was compared to that of coatings with crystalline HA contents ranging from 37.5-82%. All coatings showed an initial sharp rise in coating dissolution, which correlated with crystalline HA content, followed by a steady state dissolution rate. After 60 s at 25 degrees C, the MP-1 coating showed a 65% decrease in solubility compared to a highly amorphous coating (AM-2). All coatings showed very similar steady state dissolution rates, except for AM-2, which was significantly higher. SEM analysis showed that the AM-2 coating surface was degraded substantially more than the other coatings, resulting in partial coating exfoliation. A mechanism of coating dissolution is proposed, in which the initial rapid leaching of soluble phases from the coating leaves behind a porous layer of highly crystalline HA at the coating surface. The stability of this porous crystalline layer leads to steady state, diffusion-limited dissolution of the remainder of the coating. The observed two-regime dissolution profile can be accurately represented by a 2-parameter model, which predicts the initial sharp rise in coating dissolution followed by a slower, steady state loss in coating mass. Model parameters were determined from experimental solubility data, and were shown to correlate with the percentage of crystalline HA in the coatings. The present data suggest that the treated coating is significantly more resistant

  8. Coupled effects of hydrodynamic and solution chemistry conditions on long-term nanoparticle transport and deposition in saturated porous media

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study aims to systematically explore the coupled effects of hydrodynamic and solution chemistry conditions on the long-term transport and deposition kinetics of nanoparticles (NPs) in saturated porous media. Column transport experiments were carried out at various solution ionic strengths (IS),...

  9. Modeling of Flow, Transport and Controlled Sedimentation Phenomena during Mixing of Salt Solutions in Complex Porous Formations

    NASA Astrophysics Data System (ADS)

    Skouras, Eugene D.; Jaho, Sofia; Pavlakou, Efstathia I.; Sygouni, Varvara; Petsi, Anastasia; Paraskeva, Christakis A.

    2015-04-01

    -dimensional pore network, the dependence of the mass balance in all major directions is taken into account, either as a three-dimensional network of pores with specific geometry (cylinders, sinusoidal cells), or as a homogeneous random medium (Darcy description). The distribution of the crystals along the porous medium was calculated in the case of selective crystallization on the walls, which is the predominant effect to date in the experiments. The crystals distribution was also examined in the case where crystallization was carried out in the bulk solution. Salts sedimentation experiments were simulated both in an unsaturated porous medium and in a medium saturated with an oil phase. A comparison of the simulation results with corresponding experimental results was performed in order to design improved selective sedimentation of salts systems in porous formations. ACKNOWLEDGMENTS This research was partially funded by the European Union (European Social Fund-ESF) and Greek National Funds through the Operational program "Education and Lifelong Learning" under the action Aristeia II (Code No 4420).

  10. Salt-Finger Convection in a Stratified Fluid Layer Induced by Thermal and Solutal Capillary Motion

    NASA Technical Reports Server (NTRS)

    Chen, Chuan F.; Chan, Cho Lik

    1996-01-01

    Salt-finger convection in a double-diffusive system is a motion driven by the release of gravitational potential due to different diffusion rates. Normally, when the gravitational field is reduced, salt-finger convection together with other convective motions driven by buoyancy forces will be rapidly suppressed. However, because the destabilizing effect of the concentration gradient is amplified by the Lewis number, with values varying from 10(exp 2) for aqueous salt solutions to 10 (exp 4) for liquid metals, salt-finger convection may be generated at much reduced gravity levels. In the microgravity environment, the surface tension gradient assumes a dominant role in causing fluid motion. In this paper, we report on some experimental results showing the generation of salt-finger convection due to capillary motio on the surface of a stratified fluid layer. A numerical simulation is presented to show the cause of salt-finger convection.

  11. Pesticide Removal from Aqueous Solutions by Adding Salting Out Agents

    PubMed Central

    Moscoso, Fátima; Deive, Francisco J.; Esperança, José M. S. S.; Rodríguez, Ana

    2013-01-01

    Phase segregation in aqueous biphasic systems (ABS) composed of four hydrophilic ionic liquids (ILs): 1-butyl-3-methylimidazolium methylsulfate and 1-ethyl-3-methylimidazolium methylsulfate (CnC1im C1SO4, n = 2 and 4), tributylmethyl phosphonium methylsulfate (P4441 C1SO4) and methylpyridinium methylsulfate (C1Py C1SO4) and two high charge density potassium inorganic salts (K2CO3 and K2HPO4) were determined by the cloud point method at 298.15 K. The influence of the addition of the selected inorganic salts to aqueous mixtures of ILs was discussed in the light of the Hofmeister series and in terms of molar Gibbs free energy of hydration. The effect of the alkyl chain length of the cation on the methylsulfate-based ILs has been investigated. All the solubility data were satisfactorily correlated to several empirical equations. A pesticide (pentachlorophenol, PCP) extraction process based on the inorganic salt providing a greater salting out effect was tackled. The viability of the proposed process was analyzed in terms of partition coefficients and extraction efficiencies. PMID:24145747

  12. Ecophysiology of "halarsenatibacter silvermanii" strain SLAS-1T, gen. nov., sp. nov., a facultative chemoautotrophic arsenate respirer from salt-saturated Searles Lake, California

    USGS Publications Warehouse

    Blum, J.S.; Han, S.; Lanoil, B.; Saltikov, C.; Witte, B.; Tabita, F.R.; Langley, S.; Beveridge, T.J.; Jahnke, L.; Oremland, R.S.

    2009-01-01

    Searles Lake occupies a closed basin harboring salt-saturated, alkaline brines that have exceptionally high concentrations of arsenic oxyanions. Strain SLAS-1T was previously isolated from Searles Lake (R. S. Oremland, T. R. Kulp, J. Switzer Blum, S. E. Hoeft, S. Baesman, L. G. Miller, and J. F. Stolz, Science 308:1305-1308, 2005). We now describe this extremophile with regard to its substrate affinities, its unusual mode of motility, sequenced arrABD gene cluster, cell envelope lipids, and its phylogenetic alignment within the order Halanaero-bacteriales, assigning it the name "Halarsenatibacter silvermanii" strain SLAS-1T. We also report on the substrate dynamics of an anaerobic enrichment culture obtained from Searles Lake that grows under conditions of salt saturation and whose members include a novel sulfate reducer of the order Desulfovibriales, the archaeon Halorhabdus utahensis, as well as a close homolog of strain SLAS-1T. Copyright ?? 2009, American Society for Microbiology. All Rights Reserved.

  13. Hysteresis of colloid retention and release in saturated porous media during transients in solution chemistry.

    PubMed

    Torkzaban, Saeed; Kim, Hyunjung N; Simunek, Jiri; Bradford, Scott A

    2010-03-01

    Saturated packed column and micromodel transport studies were conducted to gain insight on mechanisms of colloid retention and release under unfavorable attachment conditions. The initial deposition of colloids in porous media was found to be a strongly coupled process that depended on solution chemistry and pore space geometry. During steady state chemical conditions, colloid deposition was not a readily reversible process, and micromodel photos indicated that colloids were immobilized in the presence of fluid drag. Upon stepwise reduction in eluting solution ionic strength (IS), a sharp release of colloids occurred in each step which indicates that colloid retention depends on a balance of applied (hydrodynamic) and resisting (adhesive) torques which varied with pore space geometry, surface roughness, and interaction energy. When the eluting fluid IS was reduced to deionized water, the final retention locations occurred near grain-grain contacts, and colloid aggregation was sometimes observed in micromodel experiments. Significant amounts of colloid retention hysteresis with IS were observed in the column experiments, and it depended on the porous medium (glass beads compared with sand), the colloid size (1.1 and 0.5 mum), and on the initial deposition IS. These observations were attributed to weak adhesive interactions that depended on the double layer thickness (e.g., the depth of the secondary minimum and/or nanoscale heterogeneity), colloid mass transfer on the solid phase to regions where the torque and force balances were favorable for retention, the number and extent of grain-grain contacts, and surface roughness. PMID:20136144

  14. Heat-induced formation of myosin oligomer-soluble filament complex in high-salt solution.

    PubMed

    Shimada, Masato; Takai, Eisuke; Ejima, Daisuke; Arakawa, Tsutomu; Shiraki, Kentaro

    2015-02-01

    Heat-induced aggregation of myosin into an elastic gel plays an important role in the water-holding capacity and texture of meat products. Here, we investigated thermal aggregation of porcine myosin in high-salt solution over a wide temperature range by dynamic light scattering experiments. The myosin samples were readily dissolved in 1.0 M NaCl at 25 °C followed by dilution into various salt concentrations. The diluted solutions consistently contained both myosin monomers and soluble filaments. The filament size decreased with increasing salt concentration and temperature. High temperatures above Tm led to at least partial dissociation of soluble filaments and thermal unfolding, resulting in the formation of soluble oligomers and binding to the persistently present soluble filaments. Such a complex formation between the oligomers and filaments has never been observed. Our results provide new insight into the heat-induced myosin gelation in high-salt solution. PMID:25445683

  15. Complex formation between excited-state saturated amines and water in n-hexane solution

    SciTech Connect

    Halpern, A.M.; Ruggles, C.J.; Zhang, X.K.

    1987-06-10

    Fluorescence spectra and decay curves of dilute solutions (<3 x 10/sup -4/ M) of triethylamine (TEA), tri-n-propylamine (TPA), and 1,4-diazabicyclo(2.2.2)octane (DABCO) in H/sub 2/O- and D/sub 2/O-saturated n-hexane reveal the presence of a complex formed between the electronically excited amine and water. The decay curves, measured between 273 and 323 K (and at 280 and 360 nm; 300 and 400 nm for DABCO), conform to the standard monomer-excimer photokinetic scheme and are analyzed accordingly. These results indicate that the binding energy of the excited TEA-H/sub 2/O complex (B*) is ca. 7.8 kcal/mol, which is larger than that of the ground-state TEA hydrate. B* for the TPA and DABCO-H/sub 2/O complexes is estimated to be ca. 10 and 8.8 kcal/mol, respectively. Stationary-state measurements are consistent with these assignments. The activation energy for the diffusion of water in n-hexane (assumed to be monomeric) appears to be very small (<1 kcal/mol). The decay constants of the three complexes studied are ca. 3.4 x 10/sup 7/ s/sup -1/ for amine-H/sub 2/O and 2.9 x 10/sup 7/ s/sup -1/ for the amine-D/sub 2/O systems. Intrinsic fluorescence quantum efficiencies of the amine-H/sub 2/O complexes are 0.17, 0.23, and 0.28 for TEA, TPA, and DABCO, respectively, at 303 K. A Foerster cycle analysis of the dry and H/sub 2/O-saturated fluorescence spectra of TEA, when taking the ground-state hydrate into account indicates that the repulsion energy of the post-fluorescence (TEA-H/sub 2/O) complex is ca. 10 kcal/mol.

  16. Evaluation of solute diffusion tortuosity factor models for variously saturated soils

    NASA Astrophysics Data System (ADS)

    Chou, Hsinyi; Wu, Laosheng; Zeng, Lingzao; Chang, Andrew

    2012-10-01

    Solute diffusion flux in soil is described by Fick's law along with a tortuosity factor to account for the tortuous and reduced diffusive pathway blocked by soil particles. Predictive models based on empirical or conceptual relationships with other more commonly measured soil attributes have been proposed to replace the time-consuming and multifarious laboratory measurements. However, these models have not been systematically tested and evaluated with soils of different textures under comparable conditions. This study determined solute diffusion coefficients and calculated tortuosity factors of a sand, a sandy clay loam, and a clay at various degrees of water saturation, and used the experimental data to test the predictive capabilities of these models. All the test models can fit the experimental data reasonably well as evidenced by low root mean square errors (RMSEs). When the proposed (fixed) parameter values were used, the widely accepted Millington and Quirk tortuosity model resulted in highest RMSEs for all three test soils. In terms of model efficiency as described by Akaike weight, however, the tortuosity factors of the sand and sandy clay loam soils are best represented by a quadratic function of volumetric soil water content (with the largest Akaike weights), while the combined parallel-series conceptual model assuming different configurations of film and pore water is the best for the clay soil. The Olesen power function tortuosity model has the second largest Akaike weights for the sand and sandy clay loam soils, while the So and Nye linear model has the second largest Akaike weight for the clay soil. The two-region linear model of log (tortuosity factor) versus soil water content uses a similar framework to the conceptual model, and it can satisfactorily fit to the experimental data well (low RMSEs), but with low Akaike weights due to the large number of parameters in the model. Adaption of the findings from this study may substantially improve solute

  17. Gas and solute diffusion in partially saturated porous media: Percolation theory and Effective Medium Approximation compared with lattice Boltzmann simulations

    NASA Astrophysics Data System (ADS)

    Ghanbarian, Behzad; Daigle, Hugh; Hunt, Allen G.; Ewing, Robert P.; Sahimi, Muhammad

    2015-01-01

    Understanding and accurate prediction of gas or liquid phase (solute) diffusion are essential to accurate prediction of contaminant transport in partially saturated porous media. In this study, we propose analytical equations, using concepts from percolation theory and the Effective Medium Approximation (EMA) to model the saturation dependence of both gas and solute diffusion in porous media. The predictions of our theoretical approach agree well with the results of nine lattice Boltzmann simulations. We find that the universal quadratic scaling predicted by percolation theory, combined with the universal linear scaling predicted by the EMA, describes diffusion in porous media with both relatively broad and extremely narrow pore size distributions.

  18. Ion aggregation in high salt solutions: Ion network versus ion cluster

    SciTech Connect

    Kim, Seongheun; Kim, Heejae; Choi, Jun-Ho; Cho, Minhaeng

    2014-09-28

    The critical aggregation phenomena are ubiquitous in many self-assembling systems. Ions in high salt solutions could also spontaneously form larger ion aggregates, but their effects on hydrogen-bond structures in water have long been controversial. Here, carrying out molecular dynamics (MD) simulation studies of high salt solutions and comparing the MD simulation results with infrared absorption and pump-probe spectroscopy of O–D stretch mode of HDO in highly concentrated salt solutions and {sup 13}C-NMR chemical shift of S{sup 13}CN{sup −} in KSCN solutions, we find evidence on the onset of ion aggregate and large-scale ion-ion network formation that concomitantly breaks water hydrogen-bond structure in certain salt solutions. Despite that these experimental results cannot provide direct evidence on the three-dimensional morphological structures of ion aggregates, they serve as reference data for verifying MD simulation methods. The MD results suggest that disrupted water hydrogen-bond network is intricately intertwined with ion-ion network. This further shows morphological variation of ion aggregate structures from ion cluster to ion network in high salt solutions that are interrelated to the onset of macroscopic aggregate formation and the water hydrogen-bond structure making and breaking processes induced by Hofmeister ions.

  19. Ion aggregation in high salt solutions: Ion network versus ion cluster

    NASA Astrophysics Data System (ADS)

    Kim, Seongheun; Kim, Heejae; Choi, Jun-Ho; Cho, Minhaeng

    2014-09-01

    The critical aggregation phenomena are ubiquitous in many self-assembling systems. Ions in high salt solutions could also spontaneously form larger ion aggregates, but their effects on hydrogen-bond structures in water have long been controversial. Here, carrying out molecular dynamics (MD) simulation studies of high salt solutions and comparing the MD simulation results with infrared absorption and pump-probe spectroscopy of O-D stretch mode of HDO in highly concentrated salt solutions and 13C-NMR chemical shift of S13CN- in KSCN solutions, we find evidence on the onset of ion aggregate and large-scale ion-ion network formation that concomitantly breaks water hydrogen-bond structure in certain salt solutions. Despite that these experimental results cannot provide direct evidence on the three-dimensional morphological structures of ion aggregates, they serve as reference data for verifying MD simulation methods. The MD results suggest that disrupted water hydrogen-bond network is intricately intertwined with ion-ion network. This further shows morphological variation of ion aggregate structures from ion cluster to ion network in high salt solutions that are interrelated to the onset of macroscopic aggregate formation and the water hydrogen-bond structure making and breaking processes induced by Hofmeister ions.

  20. Length Scale Dependence of the Dynamic Properties of Hyaluronic Acid Solutions in the Presence of Salt

    SciTech Connect

    Horkay, Ferenc; Falus, Peter; Hecht, Anne-Marie; Geissler, Erik

    2010-12-07

    In solutions of the charged semirigid biopolymer hyaluronic acid in salt-free conditions, the diffusion coefficient D{sub NSE} measured at high transfer momentum q by neutron spin echo is more than an order of magnitude smaller than that determined by dynamic light scattering, D{sub DLS}. This behavior contrasts with neutral polymer solutions. With increasing salt content, D{sub DLS} approaches D{sub NSE}, which is independent of ionic strength. Contrary to theoretical expectation, the ion-polymer coupling, which dominates the low q dynamics of polyelectrolyte solutions, already breaks down at distance scales greater than the Debye-Hueckel length.

  1. Preparation of silver nanoparticles in solution from a silver salt by laser irradiation.

    PubMed

    Abid, J P; Wark, A W; Brevet, P F; Girault, H H

    2002-04-01

    A new method is proposed for the fabrication of a well-defined size and shape distribution of silver nanoparticles in solution; the method employs direct laser irradiation of an aqueous solution containing a silver salt and a surfactant in the absence of reducing agents. PMID:12119726

  2. Particle formation and characterization of mackerel reaction oil by gas saturated solution process.

    PubMed

    Tanbirul Haque, A S M; Chun, Byung-Soo

    2016-01-01

    Most of the health benefits of fish oil can be attributed to the presence of omega-3 fatty acids like Docosahexenoic acid (DHA) and Eicosapentaenoic acid (EPA). There are few dietary sources of EPA and DHA other than oily fish. EPA and DHA have great potential effect on human health. In this research, Supercritical carbon dioxide (scCO2) extracted mackerel oil was reacted by enzyme at different systems to improve the EPA and DHA. Different types of immobilize enzyme TL-IM, RM-IM, Novozyme 435 were assessed for improving PUFAs. Best result was found at non-pressurized system using TL-IM. Reacted oil particle were obtained with polyethylene glycol by gas saturated solution process (PGSS). Different parameters like temperature, pressure, agitation speed and nozzle size effect on particle formulation were observed. SEM and PSA analysis showed, small size non spherical particles were obtained. It was found that after particle formation poly unsaturated fatty acids (PUFAs) were present in particle as same in oil. PUFAs release from particle was almost linear against constant time duration. Oil quality in particle not change significantly, in this contrast this study will be helpful for food and pharmaceutical industry to provide high EPA and DHA containing powder. PMID:26787949

  3. Fluid-loading solutions and plasma volume: Astro-ade and salt tablets with water

    NASA Technical Reports Server (NTRS)

    Fortney, Suzanne M.; Seinmann, Laura; Young, Joan A.; Hoskin, Cherylynn N.; Barrows, Linda H.

    1994-01-01

    Fluid loading with salt and water is a countermeasure used after space flight to restore body fluids. However, gastrointestinal side effects have been frequently reported in persons taking similar quantities of salt and water in ground-based studies. The effectiveness of the Shuttle fluid-loading countermeasure (8 gms salt, 0.97 liters of water) was compared to Astro-ade (an isotonic electrolyte solution), to maintain plasma volume (PV) during 4.5 hrs of resting fluid restriction. Three groups of healthy men (n=6) were studied: a Control Group (no drinking), an Astro-ade Group, and a Salt Tablet Group. Changes in PV after drinking were calculated from hematocrit and hemoglobin values. Both the Salt Tablet and Astro-ade Groups maintained PV at 2-3 hours after ingestion compared to the Control Group, which had a 6 percent decline. Side effects (thirst, stomach cramping, and diarrhea) were noted in at least one subject in both the Astro-ade and Salt Tablet Groups. Nausea and vomiting were reported in one subject in the Salt Tablet Group. It was concluded that Astro-ade may be offered as an alternate fluid-loading countermeasure but further work is needed to develop a solution that is more palatable and has fewer side effects.

  4. Temperature- and salt-responsive polyoxometalate-poly(N-isopropylacrylamide) hybrid macromolecules in aqueous solution.

    PubMed

    Zhou, Jing; Yin, Panchao; Chen, Xinyue; Hu, Lang; Liu, Tianbo

    2015-11-14

    Polyoxometalate (POM) polar head groups were covalently functionalized with poly(N-isopropylacrylamide) (PNIPAM) tails. The macromolecular hybrid demonstrates solution behavior of hydrophilic macroions by self-assembling into blackberry structures at room temperature. The hybrid behaves like an amphiphilic surfactant by forming a vesicular structure when the temperature is above the phase transition of PNIPAM. The reversible self-assembly is also salt-sensitive and the salt-induced smaller vesicular formation results from counterion-association. PMID:26383608

  5. Laser etching of metals in neutral salt solutions

    NASA Astrophysics Data System (ADS)

    Datta, M.; Romankiw, L. T.; Vigliotti, D. R.; von Gutfeld, R. J.

    1987-12-01

    We report new findings that relate to rapid maskless laser etching of steel and stainless steel in neutral solutions of sodium chloride, sodium nitrate, and potassium sulfate. Etch rates have been determined as a function of laser power, laser on-time, and solution concentration. The morphology of laser-etched holes obtained in these solutions was compared with holes obtained in pure water. Results indicate that some controlled melting occurs under certain laser conditions in addition to the metal dissolution process induced by the locally intense heat of the laser beam.

  6. Conformational changes of bovine plasma albumin prior to the salting-out of protein in concentrated salt solution.

    PubMed

    Sogami, M; Inouye, H; Nagaoka, S; Era, S

    1982-09-01

    By working at very low protein concentration (ca. 0.003%), it is possible to measure tryptophyl fluorescence intensity at 350 nm (F350) of bovine plasma albumin (BPA) as a function of pH under precipitating conditions (acidic concentrated salt solutions). Under such conditions, distinct changes in F350 were seen before the starting of precipitation of BPA and no further changes in F350 over the precipitating pH range. Comparison of pH-profiles monitored by F350 with those by solubility in the presence of various salts at various concentrations indicated that the change of solubility is observed after definite changes in conformation of the protein. PMID:7129758

  7. Facilitated transport of Cu with hydroxyapatite nanoparticles in saturated sand: Effects of solution ionic strength and composition

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Column experiments were conducted to investigate the facilitated transport of Cu in association with hydroxyapatite nanoparticles (nHAP) in water-saturated quartz sand at different solution concentrations of NaCl (0 to 100 mM) or CaCl2 (0.1 to 1.0 mM). The experimental breakthrough curves and retent...

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

    PubMed

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

    2016-06-01

    The mixing layer theory is not suitable for predicting solute transfer from initially saturated soil to surface runoff water under controlled drainage conditions. By coupling the mixing layer theory model with the numerical model Hydrus-1D, a hybrid solute transfer model has been proposed to predict soil solute transfer from an initially saturated soil into surface water, under controlled drainage water conditions. The model can also consider the increasing ponding water conditions on soil surface before surface runoff. The data of solute concentration in surface runoff and drainage water from a sand experiment is used as the reference experiment. The parameters for the water flow and solute transfer model and mixing layer depth under controlled drainage water condition are identified. Based on these identified parameters, the model is applied to another initially saturated sand experiment with constant and time-increasing mixing layer depth after surface runoff, under the controlled drainage water condition with lower drainage height at the bottom. The simulation results agree well with the observed data. Study results suggest that the hybrid model can accurately simulate the solute transfer from initially saturated soil into surface runoff under controlled drainage water condition. And it has been found that the prediction with increasing mixing layer depth is better than that with the constant one in the experiment with lower drainage condition. Since lower drainage condition and deeper ponded water depth result in later runoff start time, more solute sources in the mixing layer are needed for the surface water, and larger change rate results in the increasing mixing layer depth. PMID:26983916

  9. Continuous electrolytic decarbonation and recovery of a carbonate salt solution from a metal-contaminated carbonate solution.

    PubMed

    Kim, Kwang-Wook; Kim, Yeon-Hwa; Lee, Se-Yoon; Lee, Eil-Hee; Song, Kyusuk; Song, Kee-Chan

    2009-11-15

    This work studied the characteristic changes of a continuous electrolytic decarbonation and recovery of a carbonate salt solution from a metal-contaminated carbonate solution with changes of operational variables in an electrolytic system which consisted of a cell-stacked electrolyzer equipped with a cation exchange membrane and a gas absorber. The system could completely recover the carbonate salt solution from a uranyl carbonato complex solution in a continuous operation. The cathodic feed rate could control the carbonate concentration of the recovered solution and it affected the most transient pH drop phenomenon of a well type within the gas absorber before a steady state was reached, which caused the possibility of a CO(2) gas slip from the gas absorber. The pH drop problem could be overcome by temporarily increasing the OH(-) concentration of the cathodic solution flowing down within the gas absorber only during the time required for a steady state to be obtained in the case without the addition of outside NaOH. An overshooting peak of the carbonate concentration in the recovered solution before a steady state was observed, which was ascribed to the decarbonation of the initial solution filled within the stacked cells by a redundant current leftover from the complete decarbonation of the feeding carbonate solution. PMID:19604641

  10. Redox condition in molten salts and solute behavior: A first-principles molecular dynamics study

    NASA Astrophysics Data System (ADS)

    Nam, Hyo On; Morgan, Dane

    2015-10-01

    Molten salts technology is of significant interest for nuclear, solar, and other energy systems. In this work, first-principles molecular dynamics (FPMD) was used to model the solute behavior in eutectic LiCl-KCl and FLiBe (Li2BeF4) melts at 773 K and 973 K, respectively. The thermo-kinetic properties for solute systems such as the redox potential, solute diffusion coefficients and structural information surrounding the solute were predicted from FPMD modeling and the calculated properties are generally in agreement with the experiments. In particular, we formulate an approach to model redox energetics vs. chlorine (or fluorine) potential from first-principles approaches. This study develops approaches for, and demonstrates the capabilities of, FPMD to model solute properties in molten salts.

  11. Acemetacin cocrystals and salts: structure solution from powder X-ray data and form selection of the piperazine salt

    PubMed Central

    Sanphui, Palash; Bolla, Geetha; Nangia, Ashwini; Chernyshev, Vladimir

    2014-01-01

    Acemetacin (ACM) is a non-steroidal anti-inflammatory drug (NSAID), which causes reduced gastric damage compared with indomethacin. However, acemetacin has a tendency to form a less soluble hydrate in the aqueous medium. We noted difficulties in the preparation of cocrystals and salts of acemetacin by mechanochemical methods, because this drug tends to form a hydrate during any kind of solution-based processing. With the objective to discover a solid form of acemetacin that is stable in the aqueous medium, binary adducts were prepared by the melt method to avoid hydration. The coformers/salt formers reported are pyridine carboxamides [nicotinamide (NAM), isonicotinamide (INA), and picolinamide (PAM)], caprolactam (CPR), p-aminobenzoic acid (PABA), and piperazine (PPZ). The structures of an ACM–INA cocrystal and a binary adduct ACM–PABA were solved using single-crystal X-ray diffraction. Other ACM cocrystals, ACM–PAM and ACM–CPR, and the piperazine salt ACM–PPZ were solved from high-resolution powder X-ray diffraction data. The ACM–INA cocrystal is sustained by the acid⋯pyridine heterosynthon and N—H⋯O catemer hydrogen bonds involving the amide group. The acid⋯amide heterosynthon is present in the ACM–PAM cocrystal, while ACM–CPR contains carboxamide dimers of caprolactam along with acid–carbonyl (ACM) hydrogen bonds. The cocrystals ACM–INA, ACM–PAM and ACM–CPR are three-dimensional isostructural. The carboxyl⋯carboxyl synthon in ACM–PABA posed difficulty in assigning the position of the H atom, which may indicate proton disorder. In terms of stability, the salts were found to be relatively stable in pH 7 buffer medium over 24 h, but the cocrystals dissociated to give ACM hydrate during the same time period. The ACM–PPZ salt and ACM–nicotinamide cocrystal dissolve five times faster than the stable hydrate form, whereas the ACM–PABA adduct has 2.5 times faster dissolution rate. The pharmaceutically acceptable piperazine

  12. A salt-bridge structure in solution revealed by 2D-IR spectroscopy.

    PubMed

    Huerta-Viga, Adriana; Domingos, Sérgio R; Amirjalayer, Saeed; Woutersen, Sander

    2014-08-14

    Salt bridges are important interactions for the stability of protein conformations, but up to now it has been difficult to determine salt-bridge geometries in solution. Here we characterize the spatial structure of a salt bridge between guanidinium (Gdm(+)) and acetate (Ac(-)) using two-dimensional vibrational (2D-IR) spectroscopy. We find that as a result of salt bridge formation there is a significant change in the infrared response of Gdm(+) and Ac(-), and cross peaks between them appear in the 2D-IR spectrum. From the 2D-IR spectrum we determine the relative orientation of the transition-dipole moments of the vibrational modes of Gdm(+) and Ac(-), as well as the coupling between them. PMID:24676430

  13. Modeling solute transport through saturated zone ground water at 10 km scale: Example from the Yucca Mountain license application

    NASA Astrophysics Data System (ADS)

    Kelkar, Sharad; Ding, Mei; Chu, Shaoping; Robinson, Bruce A.; Arnold, Bill; Meijer, Arend; Eddebbarh, Al-Aziz

    2010-09-01

    This paper presents a study of solute transport through ground water in the saturated zone and the resulting breakthrough curves (BTCs), using a field-scale numerical model that incorporates the processes of advection, dispersion, matrix diffusion in fractured volcanic formations, sorption, and colloid-facilitated transport. Such BTCs at compliance boundaries are often used as performance measures for a site. The example considered here is that of the saturated zone study prepared for the Yucca Mountain license application. The saturated zone at this site occurs partly in volcanic, fractured rock formations and partly in alluvial formations. This paper presents a description of the site and the ground water flow model, the development of the conceptual model of transport, model uncertainties, model validation, and the influence of uncertainty in input parameters on the downstream BTCs at the Yucca Mountain site.

  14. Thermodynamics of extraction by solutions of amines and salts of substituted ammonium bases

    NASA Astrophysics Data System (ADS)

    Ochkin, A. V.; Sergievskii, V. V.

    1989-09-01

    Extraction systems containing amines and their salts are widely used to concentrate and separate metals. From the theoretical viewpoint, these systems are among the most complex, because of the variety of intermolecular interactions in the organic phase. The explanation and quantitative description of the observed regularities of extraction became possible only as a result of progress in the study of the thermodynamics of binary and multicomponent solutions of salts of substituted ammonium bases in non-polar organic solvents, which make it possible to distinguish the contribution of each type of interaction to the non-ideal character of the solutions. All known "anomalous" features are due to the influence of the hydration of the salts of the substituted ammonium bases on their activity. The bibliography contains 113 references.

  15. A new class of draw solutions for minimizing reverse salt flux to improve forward osmosis desalination.

    PubMed

    Nguyen, Hau Thi; Nguyen, Nguyen Cong; Chen, Shiao-Shing; Ngo, Huu Hao; Guo, Wenshan; Li, Chi-Wang

    2015-12-15

    The applications of forward osmosis (FO) have been hindered because of the lack of an optimal draw solution. The reverse salt flux from the draw solution not only reduces the water flux but also increases the cost of draw solute replenishment. Therefore, in this study, Tergitol NP7 and NP9 with a long straight carbon chain and low critical micelle concentration (CMC) were coupled with highly charged ethylenediaminetetraacetic acid (EDTA) as an innovative draw solution to minimize reverse salt diffusion in FO for the first time. The results showed that the lowest reverse salt flux of 0.067 GMH was observed when 0.1M EDTA-2Na coupled with 15mM NP7 was used as a draw solution and deionized water was used as a feed solution in FO mode (active layer facing with the feed solution). This is due to the hydrophobic interaction between the tails of NP7 and the FO membrane, thus creating layers on the membrane surface and constricting the FO membrane pores. Moreover, 1M EDTA-2Na coupled with 15mM NP7 is promising as an optimal draw solution for brackish water and sea water desalination. Average water fluxes of 7.68, 6.78, and 5.95 LMH were achieved when brackish water was used as a feed solution (5, 10, and 20g/L NaCl), and an average water flux of 3.81 LMH was achieved when sea water was used as a feed solution (35g/L NaCl). The diluted draw solution was recovered using a nanofiltration (NF-TS80) membrane with a high efficiency of 95% because of the high charge and large size of the draw solution. PMID:26298255

  16. Elastic properties of swollen polyelectrolyte gels in aqueous salt solutions.

    PubMed

    Sasaki, Shigeo

    2006-03-01

    The elastic relaxation responding to a uniaxially stretched poly(acrylic acid) rodlike gel in the aqueous NaCl solution was investigated. The relaxation elucidated the shear (mu) and bulk (K) moduli and the frictional coefficients (sigma) of the fully ionized gel at pH above 9 as functions of the degree of swelling, which was controlled by the NaCl concentration (C(S)) of the solution. Two gels, cross-linked chains of which consist of 500 (GelA500) and 50 (GelA50) monomeric units, were examined to investigate the effect of the chain length on the elastic behavior. The moduli of GelA500 increased with swelling at C(S) below 100 mM and decreased at C(S) above it. The mu values of both gels can be characterized by the power function of gel diameter, d as mu proportional, variantd(beta). The beta values being -1 at C(S) above 100 mM transitionally changed to 1.2 at C(S) about 100 mM. That is, the dimensionality of space for the chains to distribute, n(dim) [= (beta+5)/(beta+2) according to the conventional theory [Sasaki et al., J. Chem. Phys. 102, 5694 (1995)

  17. Electrosorption of inorganic salts from aqueous solution using carbon aerogels.

    PubMed

    Gabelich, Christopher J; Tran, Tri D; Suffet, I H Mel

    2002-07-01

    Capacitive deionization (CDI) with carbon aerogels has been shown to remove various inorganic species from aqueous solutions, though no studies have shown the electrosorption behavior of multisolute systems in which ions compete for limited surface area. Several experiments were conducted to determine the ion removal capacity and selectivity of carbon aerogel electrodes, using both laboratory and natural waters. Although carbon aerogel electrodes have been treated as electrical double-layer capacitors, this study showed that ion sorption followed a Langmuir isotherm, indicating monolayer adsorption. The sorption capacity of carbon aerogel electrodes was approximately 1.0-2.0 x 10(-4) equiv/g aerogel, with ion selectivity being based on ionic hydrated radius. Monovalent ions (e.g., sodium) with smaller hydrated radii were preferentially removed from solution over multivalent ions (e.g., calcium) on a percent or molar basis. Because of the relatively small average pore size (4-9 nm) of the carbon aerogel material, only 14-42 m2/g aerogel surface area was available for ion sorption. Natural organic matter may foul the aerogel surface and limit CDI effectiveness in treating natural waters. PMID:12144279

  18. Results of Analysis of Macrobatch 3 Decontaminated Salt Solution Coalescer from May 2010

    SciTech Connect

    Peters, T. B.; Fink, S. D.

    2012-12-18

    SRNL analyzed the Decontamination Salt Solution (DSS) coalescer from MCU by several analytical methods. This unit was removed from service in May 2010. The results of these analyses indicate that there is very little evidence of fouling via excessive solids, either from the leaching studies or X-Ray Diffraction (XRD) analysis.

  19. Methods for predicting properties and tailoring salt solutions for industrial processes

    NASA Technical Reports Server (NTRS)

    Ally, Moonis R.

    1993-01-01

    An algorithm developed at Oak Ridge National Laboratory accurately and quickly predicts thermodynamic properties of concentrated aqueous salt solutions. This algorithm is much simpler and much faster than other modeling schemes and is unique because it can predict solution behavior at very high concentrations and under varying conditions. Typical industrial applications of this algorithm would be in manufacture of inorganic chemicals by crystallization, thermal storage, refrigeration and cooling, extraction of metals, emissions controls, etc.

  20. Hydration structure of salt solutions from ab initio molecular dynamics

    NASA Astrophysics Data System (ADS)

    Bankura, Arindam; Carnevale, Vincenzo; Klein, Michael L.

    2013-01-01

    The solvation structures of Na^+, K^+, and Cl^- ions in aqueous solution have been investigated using density functional theory (DFT) based Car-Parrinello (CP) molecular dynamics (MD) simulations. CPMD trajectories were collected for systems containing three NaCl or KCl ion pairs solvated by 122 water molecules using three different but commonly employed density functionals (BLYP, HCTH, and PBE) with electron correlation treated at the level of the generalized gradient approximation (GGA). The effect of including dispersion forces was analyzed through the use of an empirical correction to the DFT-GGA scheme. Special attention was paid to the hydration characteristics, especially the structural properties of the first solvation shell of the ions, which was investigated through ion-water radial distribution functions, coordination numbers, and angular distribution functions. There are significant differences between the present results obtained from CPMD simulations and those provided by classical MD based on either the CHARMM force field or a polarizable model. Overall, the computed structural properties are in fair agreement with the available experimental results. In particular, the observed coordination numbers 5.0-5.5, 6.0-6.4, and 6.0-6.5 for Na^+, K^+, and Cl^-, respectively, are consistent with X-ray and neutron scattering studies but differ somewhat from some of the many other recent computational studies of these important systems. Possible reasons for the differences are discussed.

  1. pH in physiological salt solutions: direct measurements.

    PubMed

    Abrahamsen, J; Norrie, B; Andersen, P K; Stokke, D B; Nedergaard, O A

    1990-11-01

    Calculations of pH in modified Krebs solutions by inserting PCO2 and total-CO2 in the Henderson-Hasselbalch (H.-H.) equation are obvious as the equation originally served for this purpose. An exact calculation of the relation between pH and PCO2 is complicated as the concentration of bicarbonate, the dissociation constant and the solubility of CO2 change. Furthermore, the dissociation constant in the H.-H. equation is constant only if activities are used in the equation instead of stoichiometric concentrations. We therefore investigated the influence of different carbon dioxide tensions and bicarbonate concentrations on directly measured pH of organ baths aerated with mass-spectrometric analyzed O2-CO2 gases. For reference precision buffers were used. The measured pH values differed distinctly from calculated pH values in the acidic and alkaline parts of the pH interval investigated (6.57-8.15). Measurements of actual pH with proper calibration standards therefore seem mandatory. PMID:2177306

  2. Hydration structure of salt solutions from ab initio molecular dynamics

    SciTech Connect

    Bankura, Arindam; Carnevale, Vincenzo; Klein, Michael L.

    2013-01-07

    The solvation structures of Na{sup +}, K{sup +}, and Cl{sup -} ions in aqueous solution have been investigated using density functional theory (DFT) based Car-Parrinello (CP) molecular dynamics (MD) simulations. CPMD trajectories were collected for systems containing three NaCl or KCl ion pairs solvated by 122 water molecules using three different but commonly employed density functionals (BLYP, HCTH, and PBE) with electron correlation treated at the level of the generalized gradient approximation (GGA). The effect of including dispersion forces was analyzed through the use of an empirical correction to the DFT-GGA scheme. Special attention was paid to the hydration characteristics, especially the structural properties of the first solvation shell of the ions, which was investigated through ion-water radial distribution functions, coordination numbers, and angular distribution functions. There are significant differences between the present results obtained from CPMD simulations and those provided by classical MD based on either the CHARMM force field or a polarizable model. Overall, the computed structural properties are in fair agreement with the available experimental results. In particular, the observed coordination numbers 5.0-5.5, 6.0-6.4, and 6.0-6.5 for Na{sup +}, K{sup +}, and Cl{sup -}, respectively, are consistent with X-ray and neutron scattering studies but differ somewhat from some of the many other recent computational studies of these important systems. Possible reasons for the differences are discussed.

  3. Hydration structure of salt solutions from ab initio molecular dynamics.

    PubMed

    Bankura, Arindam; Carnevale, Vincenzo; Klein, Michael L

    2013-01-01

    The solvation structures of Na(+), K(+), and Cl(-) ions in aqueous solution have been investigated using density functional theory (DFT) based Car-Parrinello (CP) molecular dynamics (MD) simulations. CPMD trajectories were collected for systems containing three NaCl or KCl ion pairs solvated by 122 water molecules using three different but commonly employed density functionals (BLYP, HCTH, and PBE) with electron correlation treated at the level of the generalized gradient approximation (GGA). The effect of including dispersion forces was analyzed through the use of an empirical correction to the DFT-GGA scheme. Special attention was paid to the hydration characteristics, especially the structural properties of the first solvation shell of the ions, which was investigated through ion-water radial distribution functions, coordination numbers, and angular distribution functions. There are significant differences between the present results obtained from CPMD simulations and those provided by classical MD based on either the CHARMM force field or a polarizable model. Overall, the computed structural properties are in fair agreement with the available experimental results. In particular, the observed coordination numbers 5.0-5.5, 6.0-6.4, and 6.0-6.5 for Na(+), K(+), and Cl(-), respectively, are consistent with X-ray and neutron scattering studies but differ somewhat from some of the many other recent computational studies of these important systems. Possible reasons for the differences are discussed. PMID:23298049

  4. Escherichia coli O157:H7 Transport in Saturated Porous Media: Role of Solution Chemistry and Surface Macromolecules

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The transport and deposition behavior of Escherichia coli O157:H7 was investigated in saturated packed-bed columns and micromodel systems over a range of ionic strength (IS) (1, 10, and 100 mM) and pH (5.8, 8.4, and 9.2). At a given IS, enhanced solution pH resulted in decreased deposition as a res...

  5. Explicit-water theory for the salt-specific effects and Hofmeister series in protein solutions

    NASA Astrophysics Data System (ADS)

    Kalyuzhnyi, Yuriy V.; Vlachy, Vojko

    2016-06-01

    Effects of addition of salts on stability of aqueous protein solutions are studied theoretically and the results are compared with experimental data. In our approach, all the interacting species, proteins, ions, and water molecules, are accounted for explicitly. Water molecules are modeled as hard spheres with four off-center attractive square-well sites. These sites serve to bind either another water or to solvate the ions or protein charges. The ions are represented as charged hard spheres, and decorated by attractive sites to allow solvation. Spherical proteins simultaneously possess positive and negative groups, represented by charged hard spheres, attached to the surface of the protein. The attractive square-well sites, mimicking the protein-protein van der Waals interaction, are located on the surface of the protein. To obtain numerical results, we utilized the energy route of Wertheim's associative mean spherical approximation. From measurable properties, we choose to calculate the second virial coefficient B2, which is closely related to the tendency of proteins to aggregate and eventually crystalize. Calculations are in agreement with experimental trends: (i) For low concentration of added salt, the alkali halide salts follow the inverse Hofmeister series. (ii) At higher concentration of added salt, the trend is reversed. (iii) When cations are varied, the salts follow the direct Hofmeister series. (iv) In contrast to the colloidal theories, our approach correctly predicts the non-monotonic behavior of B2 upon addition of salts. (v) With respect to anions, the theory predicts for the B2 values to follow different sequences below and above the iso-ionic point, as also confirmed experimentally. (vi) A semi-quantitative agreement between measured and calculated values for the second virial coefficient, as functions of pH of solution and added salt type and concentration, is obtained.

  6. Explicit-water theory for the salt-specific effects and Hofmeister series in protein solutions.

    PubMed

    Kalyuzhnyi, Yuriy V; Vlachy, Vojko

    2016-06-01

    Effects of addition of salts on stability of aqueous protein solutions are studied theoretically and the results are compared with experimental data. In our approach, all the interacting species, proteins, ions, and water molecules, are accounted for explicitly. Water molecules are modeled as hard spheres with four off-center attractive square-well sites. These sites serve to bind either another water or to solvate the ions or protein charges. The ions are represented as charged hard spheres, and decorated by attractive sites to allow solvation. Spherical proteins simultaneously possess positive and negative groups, represented by charged hard spheres, attached to the surface of the protein. The attractive square-well sites, mimicking the protein-protein van der Waals interaction, are located on the surface of the protein. To obtain numerical results, we utilized the energy route of Wertheim's associative mean spherical approximation. From measurable properties, we choose to calculate the second virial coefficient B2, which is closely related to the tendency of proteins to aggregate and eventually crystalize. Calculations are in agreement with experimental trends: (i) For low concentration of added salt, the alkali halide salts follow the inverse Hofmeister series. (ii) At higher concentration of added salt, the trend is reversed. (iii) When cations are varied, the salts follow the direct Hofmeister series. (iv) In contrast to the colloidal theories, our approach correctly predicts the non-monotonic behavior of B2 upon addition of salts. (v) With respect to anions, the theory predicts for the B2 values to follow different sequences below and above the iso-ionic point, as also confirmed experimentally. (vi) A semi-quantitative agreement between measured and calculated values for the second virial coefficient, as functions of pH of solution and added salt type and concentration, is obtained. PMID:27276970

  7. A traditional Japanese-style salt field is a niche for haloarchaeal strains that can survive in 0.5% salt solution

    PubMed Central

    Fukushima, Tadamasa; Usami, Ron; Kamekura, Masahiro

    2007-01-01

    Background Most of the haloarchaeal strains have been isolated from hypersaline environments such as solar evaporation ponds, salt lakes, or salt deposits, and they, with some exceptions, lyse or lose viability in very low-salt concentrations. There are no salty environments suitable for the growth of haloarchaea in Japan. Although Natrialba asiatica and Haloarcula japonica were isolated many years ago, the question, "Are haloarchaea really thriving in natural environments of Japan?" has remained unanswered. Results Ten strains were isolated from a traditional Japanese-style salt field at Nie, Noto Peninsula, Japan by plating out the soil samples directly on agar plates containing 30% (w/v) salts and 0.5% yeast extract. They were most closely related to strains of three genera, Haladaptatus, Halococcus, and Halogeometricum. Survival rates in 3% and 0.5% SW (Salt Water, solutions containing salts in approximately the same proportions as found in seawater) solutions at 37°C differed considerably depending on the strains. Two strains belonging to Halogeometricum as well as the type strain Hgm. borinquense died and lysed immediately after suspension. Five strains that belonged to Halococcus and a strain that may be a member of Halogeometricum survived for 1–2 days in 0.5% SW solution. Two strains most closely related to Haladaptatus possessed extraordinary strong tolerance to low salt conditions. About 20 to 34% of the cells remained viable in 0.5% SW after 9 days incubation. Conclusion In this study we have demonstrated that haloarchaea are really thriving in the soil of Japanese-style salt field. The haloarchaeal cells, particularly the fragile strains are suggested to survive in the micropores of smaller size silt fraction, one of the components of soil. The inside of the silt particles is filled with concentrated salt solution and kept intact even upon suspension in rainwater. Possible origins of the haloarchaea isolated in this study are discussed. PMID

  8. Modeling Solute Thermokinetics in LiCI-KCI Molten Salt for Nuclear Waste Separation

    SciTech Connect

    Morgan, Dane; Eapen, Jacob

    2013-10-01

    Recovery of actinides is an integral part of a closed nuclear fuel cycle. Pyrometallurgical nuclear fuel recycling processes have been developed in the past for recovering actinides from spent metallic and nitride fuels. The process is essentially to dissolve the spent fuel in a molten salt and then extract just the actinides for reuse in a reactor. Extraction is typically done through electrorefining, which involves electrochemical reduction of the dissolved actinides and plating onto a cathode. Knowledge of a number of basic thermokinetic properties of salts and salt-fuel mixtures is necessary for optimizing present and developing new approaches for pyrometallurgical waste processing. The properties of salt-fuel mixtures are presently being studied, but there are so many solutes and varying concentrations that direct experimental investigation is prohibitively time consuming and expensive (particularly for radioactive elements like Pu). Therefore, there is a need to reduce the number of required experiments through modeling of salt and salt-fuel mixture properties. This project will develop first-principles-based molecular modeling and simulation approaches to predict fundamental thermokinetic properties of dissolved actinides and fission products in molten salts. The focus of the proposed work is on property changes with higher concentrations (up to 5 mol%) of dissolved fuel components, where there is still very limited experimental data. The properties predicted with the modeling will be density, which is used to assess the amount of dissolved material in the salt; diffusion coefficients, which can control rates of material transport during separation; and solute activity, which determines total solubility and reduction potentials used during electrorefining. The work will focus on La, Sr, and U, which are chosen to include the important distinct categories of lanthanides, alkali earths, and actinides, respectively. Studies will be performed using LiCl-KCl salt

  9. Salt-water-freshwater transient upconing - An implicit boundary-element solution

    USGS Publications Warehouse

    Kemblowski, M.

    1985-01-01

    The boundary-element method is used to solve the set of partial differential equations describing the flow of salt water and fresh water separated by a sharp interface in the vertical plane. In order to improve the accuracy and stability of the numerical solution, a new implicit scheme was developed for calculating the motion of the interface. The performance of this scheme was tested by means of numerical simulation. The numerical results are compared to experimental results for a salt-water upconing under a drain problem. ?? 1985.

  10. Investigation of the Ionic Hydration in Aqueous Salt Solutions by Soft X-ray Emission Spectroscopy.

    PubMed

    Jeyachandran, Y L; Meyer, F; Benkert, A; Bär, M; Blum, M; Yang, W; Reinert, F; Heske, C; Weinhardt, L; Zharnikov, M

    2016-08-11

    Understanding the molecular structure of the hydration shells and their impact on the hydrogen bond (HB) network of water in aqueous salt solutions is a fundamentally important and technically relevant question. In the present work, such hydration effects were studied for a series of representative salt solutions (NaCl, KCl, CaCl2, MgCl2, and KBr) by soft X-ray emission spectroscopy (XES) and resonant inelastic soft X-ray scattering (RIXS). The oxygen K-edge XES spectra could be described with three components, attributed to initial state HB configurations in pure water, water molecules that have undergone an ultrafast dissociation initiated by the X-ray excitation, and water molecules in contact with salt ions. The behavior of the individual components, as well as the spectral shape of the latter component, has been analyzed in detail. In view of the role of ions in such effects as protein denaturation (i.e., the Hofmeister series), we discuss the ion-specific nature of the hydration shells and find that the results point to a predominant role of anions as compared to cations. Furthermore, we observe a concentration-dependent suppression of ultrafast dissociation in all salt solutions, associated with a significant distortion of intact HB configurations of water molecules facilitating such a dissociation. PMID:27442708

  11. Solution Asymmetry and Salt Expand Fluid-Fluid Coexistence Regions of Charged Membranes.

    PubMed

    Kubsch, Bastian; Robinson, Tom; Lipowsky, Reinhard; Dimova, Rumiana

    2016-06-21

    Liquid-liquid phase separation in giant unilamellar vesicles (GUVs) leads to the formation of intramembrane domains. To mimic charged biological membranes, we studied phase separation and domain formation in GUVs of ternary lipid mixtures composed of egg sphingomyelin, cholesterol, and the negatively charged lipid dioleoylphosphatidylglycerol. The GUVs were exposed to solutions of sucrose and high-saline buffer. The phase diagram was determined using epifluorescence microscopy for vesicle populations with symmetric and asymmetric solution compositions across the membranes. Trans-membrane solution asymmetry was found to affect the membrane phase state. Furthermore, compared to the case of salt-free conditions, the phase diagram in the presence of high-saline buffer (both symmetrically or asymmetrically present across the membrane) was found to exhibit a significantly extended region of liquid-ordered and liquid-disordered coexistence. These observations were confirmed on single GUVs using microfluidics and confocal microscopy. Moreover, we found that the miscibility temperatures markedly increased for vesicles in the presence of symmetric and asymmetric salt solutions. Our results demonstrate a substantial effect of salt and solution asymmetry on the phase behavior of charged membranes, which has direct implications for protein adsorption onto these membranes and for the repartitioning of proteins within the membrane domains. PMID:27288275

  12. Films, Preimpregnated Tapes and Composites Made from Polyimide "Salt-Like" Solutions

    NASA Technical Reports Server (NTRS)

    Cano, Roberto J. (Inventor); Weiser, Erik S. (Inventor); St.Clair, Terry L. (Inventor); Echigo, Yoshiaki (Inventor); Kaneshiro, Hisayasu (Inventor)

    2001-01-01

    High quality films, preimpregnated tape (prepegs), and composites have been fabricated from polyimide precursor 'saltlike' solutions. These salt-like solutions have a low viscosity (5,000 to 10,000 cp) and a high solids content (50-65% by weight) and can be coated onto reinforcing fiber to produce prepegs with excellent tack and drape at 12-15% residual solvent (approximately 4-6% water from thermal imidization reaction). The processing of these types of prepegs significantly overcomes solvent removal problems and allows excellent fiber wet out. In addition, the physical characteristics of the polyimide precursor salt-like solutions permits processing into high-performance materials through the use of standard prepregging and composite fabrication equipment. The resultant composites are of high quality.

  13. Solution-derived sodalite made with Si- and Ge-ethoxide precursors for immobilizing electrorefiner salt

    NASA Astrophysics Data System (ADS)

    Riley, Brian J.; Lepry, William C.; Crum, Jarrod V.

    2016-01-01

    Chlorosodalite has the general form of Na8(AlSiO4)6Cl2 and this paper describes experiments conducted to synthesize sodalite with a solution-based approach to immobilize a simulated spent electrorefiner salt solution containing a mixture of alkali, alkaline earth, and lanthanide chlorides. The reactants used were the salt solution, NaAlO2, and either Si(OC2H5)4 or Ge(OC2H5)4. Additionally, seven different glass sintering aids (at loadings of 5 mass%) were evaluated as sintering aids for consolidating the as-made powders using a cold-press-and-sinter technique. This process of using alkoxide additives for the Group IV component can be used to produce large quantities of sodalite at near-room temperature as compared to a method where colloidal silica was used as the silica source. However, the small particle sizes inhibited densification during heat treatments.

  14. Molecular dynamics simulations of the surface tension and structure of salt solutions and clusters.

    PubMed

    Sun, Lu; Li, Xin; Hede, Thomas; Tu, Yaoquan; Leck, Caroline; Ågren, Hans

    2012-03-15

    Sodium halides, which are abundant in sea salt aerosols, affect the optical properties of aerosols and are active in heterogeneous reactions that cause ozone depletion and acid rain problems. Interfacial properties, including surface tension and halide anion distributions, are crucial issues in the study of the aerosols. We present results from molecular dynamics simulations of water solutions and clusters containing sodium halides with the interatomic interactions described by a conventional force field. The simulations reproduce experimental observations that sodium halides increase the surface tension with respect to pure water and that iodide anions reach the outermost layer of water clusters or solutions. It is found that the van der Waals interactions have an impact on the distribution of the halide anions and that a conventional force field with optimized parameters can model the surface tension of the salt solutions with reasonable accuracy. PMID:22352372

  15. Analysis of frozen salt solutions with laser-induced breakdown spectroscopy under Martian conditions

    NASA Astrophysics Data System (ADS)

    Schröder, S.; Pavlov, S. G.; Hübers, H.-W.; Rauschenbach, I.; Jessberger, E. K.

    2010-05-01

    Laser-induced breakdown spectroscopy (LIBS) is a powerful analytical technique for determining the elemental composition of materials. It can be applied in-situ to geological surfaces on planetary missions. Since pure liquid water is unstable at the current surface conditions on Mars, i.e. low surface pressure and temperatures ranging from 140 K to 300 K, salt solutions or brines are of particular interest. It has been suggested that salts could stabilize liquid water on Mars lowering the freezing point of the solution and suppressing evaporation rates. The appropriate salts have been found on Mars in different locations. In this study LIBS is employed for the investigation of frozen sulphate and chloride solutions under Martian conditions in a dedicated simulation chamber. For the laboratory experiments, various salt solutions were prepared with different concentrations. To produce ice with only little inclusions of air, the samples were degassed before freezing them in a copper container. The measurements were performed at 240 K by cooling with liquid nitrogen and controlled heating. A constant flow of a Martian atmosphere-like gas mixture at a pressure of approximately 6 hPa was maintained through the chamber during the measurements. A Q-switched Nd:YAG laser operating at 1064nm and at 10 Hz was used to ablate material and to generate a plasma on the frozen sample's surface. The emitted light of the plasma was collected into the entrance slit of an echelle spectrometer (LTB Aryelle Butterfly) by a toroid mirror. A time-gated ICCD camera (Andor) at the exit of the spectrometer recorded the plasma emission signal. The laser beam was focused at a new position for each measurement. The delay time and the integration time of the spectrometer have been optimized to obtain good signal-to-noise ratios up to 150 while at the same time not losing signals from fast recombining ions. First, the spectra of several frozen salt solutions were investigated qualitatively

  16. Laser-induced breakdown spectroscopy for analysis of frozen salt solutions under Martian conditions

    NASA Astrophysics Data System (ADS)

    Schröder, Susanne; Pavlov, Sergey; Hübers, Heinz-Wilhelm; Rauschenbach, Isabelle; Jessberger, Elmar K.

    Laser-induced breakdown spectroscopy (LIBS) is a powerful analytical technique for determin-ing the elemental composition of materials. It can be applied in-situ to geological surfaces on planetary missions. Since pure liquid water is unstable at the current surface conditions on Mars, i.e. low surface pressure and temperatures ranging from 140 K to 300 K, salt solutions or brines are of particular interest. It has been suggested that salts could stabilize liquid water on Mars lowering the freezing point of the solution and suppressing evaporation rates. The ap-propriate salts have been found on Mars in different locations. In this study LIBS is employed for the investigation of frozen sulphate and chloride solutions under Martian conditions in a dedicated simulation chamber. For the laboratory experiments, various salt solutions were prepared with different concen-trations. To produce ice with only little inclusions of air, the samples were degassed before freezing them in a copper container. The measurements were performed at 240 K by cooling with liquid nitrogen and controlled heating. A constant flow of a Martian atmosphere-like gas mixture at a pressure of approximately 6 hPa was maintained through the chamber during the measurements. A Q-switched Nd:YAG laser operating at 1064nm and at 10 Hz was used to ablate material and to generate a plasma on the frozen sample's surface. The emitted light of the plasma was collected into the entrance slit of an echelle spectrometer (LTB Aryelle But-terfly) by a toroid mirror. A time-gated ICCD camera (Andor) at the exit of the spectrometer recorded the plasma emission signal. The laser beam was focused at a new position for each measurement. The delay time and the integration time of the spectrometer have been optimized to obtain good signal-to-noise ratios up to 150 while at the same time not losing signals from fast recombining ions. First, the spectra of several frozen salt solutions were investigated qualitatively

  17. Identification of frozen salt solutions combining LIBS and multivariate analysis methods

    NASA Astrophysics Data System (ADS)

    Schröder, S.; Pavlov, S.; Jessberger, E.; Hübers, H.

    2012-12-01

    Laser-induced breakdown spectroscopy (LIBS) is an emission spectroscopy technique and relies on evaporating material from the target by focusing radiation from a pulsed laser onto the sample surface. The generated plasma is analyzed spectroscopically and information about the elemental composition is obtained from specific atomic or ionic transitions and the associated emanating photons, which result in characteristic spectral lines. For the geochemical investigation of extraterrestrial surfaces LIBS has been suggested as a powerful analytical tool and is part of the payload on NASA's rover MSL (Mars Science Laboratory), which landed in the Gale crater on Mars in August 2012. This is the first time that LIBS is used for planetary science. In this study, salts, which are considered relevant for Martian geochemistry were investigated, including sulfates, chlorides, and perchlorates. An infrared Nd:YAG laser (1064 nm wavelength, up to 220 mJ, 8 ns pulse duration, 10 Hz repetition rate) generated the plasma at distances < 1 m. The plasma emission was detected with an echelle spectrometer with a time-gated intensified CCD enabling a continuous coverage from 280 nm to 900 nm. The salts were investigated in their pure form and in frozen salt solutions under simulated Martian atmospheric conditions with an appropriate gas mixture composed of 95.55 % Vol. CO2 at a pressure of 7 mbar. The influence of different gating parameters for time-resolved detection of the plasma was studied and parameters best suited for the LIBS analysis of ices were determined. The emission lines of metals are detectable with LIBS with high signal-to-noise ratios, which facilitates a relatively straightforward identification of the type of the cation. Due to weak excitation of the high-energy levels required for efficient radiative transitions of both sulfur and chlorine ions, their emission lines are typically weak and hardly detectable, in particular in the LIBS spectra of the ices. This

  18. Effect of heat stable salts on MDEA solution corrosivity: Part 2

    SciTech Connect

    Rooney, P.C.; DuPart, M.S.; Bacon, T.R.

    1997-04-01

    A comprehensive coupon corrosion testing program was undertaken to address the effect of various heat stable salts on methyldiethanolamine (MDEA) corrosivity to carbon steel and various stainless steels. Corrosion rates of carbon steel, 304SS, 316SS and 410SS liquid and vapor coupons towards MDEA, and MDEA containing various anions, at 180 F and 250 F, were measured in a reactor. Corrosion results of two refinery plant solutions before and after caustic neutralization were also performed. Based on these results, guidelines were determined for heat stable amine salt (HSAS) levels of oxalates, sulfates, formates, acetates and thiosulfates. In addition, caustic neutralization guidelines for MDEA heat stable salts were determined. Ongoing results include MDEA corrosivity with succinates, and malonates, glycolates, SO{sub 2} and ammonia.

  19. Salt effects in extraction of ethanol, 1-butanol and acetone from aqueous solutions

    SciTech Connect

    Malinowski, J.J.; Daugulis, A.J. . Dept. of Chemical Engineering)

    1994-09-01

    Experimental studies were performed to assess the effect of salt addition on the extraction of 1-butanol, ethanol and acetone from dilute aqueous solutions using cyclopentanol, n-valeraldehyde, tert-amyl alcohol, and Adol 85NF as extractants. The liquid-liquid partitioning was examined for a few strong electrolytes in a broad range of concentrations. Results demonstrate that the distribution coefficient and selectivity in systems with reduced water activity resulting from salt addition were markedly increased. These observations can be qualitatively explained on the basis of the hydration theory. It was also determined that strong electrolytes added to the aqueous feed reduced extractant solubility in the aqueous phase, thus contributing to lower solvent losses. The results showed that the extraction efficiency was not significantly affected by increasing salt content beyond a level that reduces the water activity to a value of 0.92.

  20. Effects of ion exchange on stream solute fluxes in a basin receiving highway deicing salts

    USGS Publications Warehouse

    Shanley, J.B.

    1994-01-01

    At Fever Brook, a 1260-ha forested basin in central Massachusetts, highway deicing salt application increased the solute flux in streamflow by 120% above background flux (equivalent basis) during a 2-yr period. Attempts to isolate the nonsalt component of stream solute fluxes have commonly subtracted salt contributions based on the net Cl flux (Cl output in streamflow minus Cl input in precipitation). In these studies, any net Na flux in excess of the amount needed to balance the net Cl flux has been attributed to weathering. At Fever Brook, however, the net output of Na was less than the net output of Cl, suggesting a loss of Na within the basin. The Na sink was inferred to be cation exchange of Na for Ca and Mg in the soil. A method was developed to quantify the exchange based on a Na budget, which included an independent estimate of the Na flux from weathering. The amount of exchange was apportioned to Ca and Mg based on their relative concentrations in the stream. The background fluxes of Ca and Mg (i.e., those that would occur in the absence of deicing salts) were calculated by subtracting the amounts from ion exchange plus the much smaller direct contributions in deicing salts from the observed fluxes. Ion exchange and direct salt contributions increased the net output fluxes of Ca and Mg, each by 44% above background. In basins that receive deicing salts, failure to account for cation exchange thus may result in an underestimate of the flux of Na from weathering and overestimates of the fluxes of Ca and Mg from weathering.

  1. A finite-element simulation model for saturated-unsaturated, fluid-density-dependent ground-water flow with energy transport or chemically- reactive single-species solute transport

    USGS Publications Warehouse

    Voss, C.I.

    1984-01-01

    SUTRA (Saturated-Unsaturated Transport) is a computer program which can be used to simulate the movement of fluid and the transport of either energy or dissolved substances in a subsurface environment. The model employs a two-dimensional hybrid finite-element and integrated-finite-difference method to approximate the governing equations that describe the two interdependent processes that are simulated by SUTRA: (1) fluid density-dependent saturated or unsaturated groundwater flow, and either (2a) transport of a solute in the groundwater, in which the solute may be subject to: equilibrium adsorption on the porous matrix, and both first-order and zero-order production or decay, or, (2b) transport of thermal energy in the groundwater and solid matrix of the aquifer. SUTRA provides, as the primary calculated results, fluid pressures and either solute concentrations or temperatures, as they vary with time, everywhere in the simulated subsurface system. SUTRA may also be used to simulate simpler subsets of the above process. SUTRA may be employed for areal and cross-sectional models of saturated groundwater flow systems, and for cross-sectional models of unsaturated zone flow. Solute transport simulation using SUTRA may be used to simulate natural or man-induced chemical transport, solute sorption, production and decay. SUTRA may be used for simulation of variable density leachate movement, and for cross-sectional simulation of salt-water intrusion in aquifers at near-well or regional scales, with either dispersed or relatively sharp transition zones between fresh water and salt water. SUTRA energy transport simulation may be employed to model thermal regimes in aquifers, subsurface heat conduction, aquifer thermal energy storage systems, geothermal reservoirs, thermal pollution of aquifers, and natural hydrogeologic convection systems. (USGS)

  2. Laboratory analysis of fluid flow and solute transport through a variably saturated fracture embedded in porous tuff

    SciTech Connect

    Chuang, Y.; Haldeman, W.R.; Rasmussen, T.C.; Evans, D.D.

    1990-02-01

    Laboratory techniques are developed that allow concurrent measurement of unsaturated matrix hydraulic conductivity and fracture transmissivity of fractured rock blocks. Two Apache Leap tuff blocks with natural fractures were removed from near Superior, Arizona, shaped into rectangular prisms, and instrumented in the laboratory. Porous ceramic plates provided solution to block tops at regulated pressures. Infiltration tests were performed on both test blocks. Steady flow testing of the saturated first block provided estimates of matrix hydraulic conductivity and fracture transmissivity. Fifteen centimeters of suction applied to the second block top showed that fracture flow was minimal and matrix hydraulic conductivity was an order of magnitude less than the first block saturated matrix conductivity. Coated-wire ion-selective electrodes monitored aqueous chlorided breakthrough concentrations. Minute samples of tracer solution were collected with filter paper. The techniques worked well for studying transport behavior at near-saturated flow conditions and also appear to be promising for unsaturated conditions. Breakthrough curves in the fracture and matrix, and a concentration map of chloride concentrations within the fracture, suggest preferential flows paths in the fracture and substantial diffusion into the matrix. Average travel velocity, dispersion coefficient and longitudinal dispersivity in the fracture are obtained. 67 refs., 54 figs., 23 tabs.

  3. Tension-saturated and unsaturated flows from line sources in subsurface irrigation: Riesenkampf's and Philip's solutions revisited

    NASA Astrophysics Data System (ADS)

    Kacimov, A. R.; Obnosov, Yu. V.

    2016-03-01

    Riesenkampf's (1938), R-38 (referred to here as R-38), analytical solution for steady 2-D flow from a buried line source in a homogeneous Green-Ampt soil, with a wetting plume bounded by a free surface (capillary fringe), is compared with Philip's (1969), (P-69), one for genuinely unsaturated wetting of Gardner's infinite-extension soil. Conformal mappings are used in R-38, from which we derived the flow net, pore-water isobars, isochrones, fields of Darcian velocity and resultant force acting on saturated porous skeleton, fine geometry (shape and size) of the constant-head contour encompassing a mole-emitter or leaky-pipe, as well as the dependence of the total discharge per unit pipe length on uniform pressure in the pipe, capillarity of the soil, radius of the pipe, and saturated hydraulic conductivity. An ovalic "water table" isobar, encompassing P-69 source, is compared with one of R-38 for a fixed discharge and saturated conductivity but adjusted sorptive numbers. The Whisler and Bouwer (1970) relation between the static height of capillary rise and sorptive number is shown to give a good match between R-38 and P-69 isobars. This allows to use R-38 in the source vicinity and P-69 in the far-field zone. Computer algebra (Mathematica) routines are used for visualization of the known and extended R-38 and P-69 solutions.

  4. Solution-Derived Sodalite Made with Si- and Ge-Ethoxide Precursors for Immobilizing electrorefiner salt

    SciTech Connect

    Riley, Brian J.; Lepry, William C.; Crum, Jarrod V.

    2016-01-01

    Chlorosodalite has the general form of Na8(AlSiO4)6Cl2 and this paper describes experiments conducted to synthesize sodalite to immobilize a mixed chloride salt using solution-based techniques. Sodalites were made using different Group IV contributions from either Si(OC2H5)4 or Ge(OC2H5)4, NaAlO2, and a simulated spent electrorefiner salt solution containing a mixture of alkali, alkaline earth, and lanthanide chlorides. Additionally, 6 glass binders at low loadings of 5 mass% were evaluated as sintering aids for the consolidation process. The approach of using the organic Group IV additives can be used to produce large quantities of sodalite at room temperature and shows promise over a method where colloidal silica is used as the silica source. However, the small particle sizes inhibited densification during pressure-less sintering.

  5. Prediction of subsidence resulting from creep closure of solutioned-mined caverns in salt domes

    SciTech Connect

    Neal, J.T.

    1991-01-01

    The prediction of subsidence rates over a range of areal configurations of solution-mined caverns in salt domes is possible, based on some fifty years of history in solution mining. Several approaches contribute to predictions: site-specific observations obtained from subsidence monitoring; numerical modeling, now becoming more practicable and credible; salt-creep data from testing; and rule-of-thumb methods, based on experience. All of these approaches contribute to understanding subsidence but none are totally reliable alone. The example of subsidence occurring at the Strategic Petroleum Reserve sites demonstrates several principles of cavern creep closure, the main cause of the subsidence, and shows that reliable projections of future subsidence are possible. 13 refs., 6 figs.

  6. Inefficacy of osmotic backwash induced by sodium chloride salt solution in controlling SWRO membrane fouling

    NASA Astrophysics Data System (ADS)

    Farooque, A. Mohammed; Al-Jeshi, Subhi; Saeed, Mohamed O.; Alreweli, Ali

    2014-12-01

    A study was conducted to evaluate the efficacy of osmotic backwash induced by high salt (NaCl) concentration solution on feed side of seawater reverse osmosis (SWRO) membranes, online and offline, in controlling membrane fouling and therefore minimizing/eliminating the need for chemical cleaning. SWRO membranes were deliberately fouled by feeding seawater from an open intake located on the Arabian Gulf Coast without dosing chemicals. The fouled membranes were subjected to offline cleaning with the salt solution of up to 25 % concentration. Despite the partial removal of foulants from the membrane surface, SWRO membrane performance could not be restored, indicating the ineffectiveness of osmotic backwash in aiding offline salt cleaning. Similarly, online osmotic backwash was found to be not only ineffective in removing foulants from membrane surfaces but actually increased the fouling rate, as indicated by faster fouling rates compared to other cases. Although the driving force required for the osmotic backwash existed, the generated back flow proved to be insufficient to detach foulants from membrane surfaces. During the study period, the average SWRO membrane flux was maintained between 19 and 23 LMH, whereas the average generated back flow flux by high salt concentration solution was only 11 LMH, which was not adequate to remove foulants from membrane surfaces. Moreover, it seems that the membrane configuration as well as inherent microstructure of SWRO membrane places certain constraints on the osmotic backwash process and renders osmotic backwash ineffective in tackling SWRO membrane fouling. Hence, chemical cleaning is essential to restore SWRO membrane performance whenever fouling occurs, and the use of highly concentrated salt solution does not have any significant benefit. Membrane autopsy revealed only an insignificant accumulation of biofouling layer despite the absence of disinfection. However, it was shown that culturable biofilm bacteria species

  7. Solute transport through a pine-bark based substrate under saturated and unsaturated conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An understanding of how dissolved mineral nutrient ions (solutes) move through pine bark substrates during the application of irrigation water is vital to better understand nutrient transport and leaching from containerized crops during an irrigation event. However, current theories on solute transp...

  8. Influence of phosphate and solution pH on the mobility of ZnO nanoparticles in saturated sand.

    PubMed

    Li, Lingxiangyu; Schuster, Michael

    2014-02-15

    The mobility of nanoparticles (NPs) strongly depends on the chemical characterization of the environmental medium. However, the influence of phosphate on NPs mobility was ignored by scientists despite the serious phosphate contamination in natural environments. Hence, the influence of phosphate and solution pH on the mobility of zinc oxide nanoparticles (ZnO-NPs) was investigated in water-saturated sand representative of groundwater aquifers, which encompassed a range of P/Zn molar ratios (P/Zn: 0-4) and pH (4.8-10.0). The transport of ZnO-NPs was dramatically enhanced in the presence of phosphate, even at a low P/Zn molar ratio namely 0.25, and the retention of ZnO-NPs in the saturated sand decreased with increasing P/Zn molar ratio. Moreover, attachment efficiencies (α) and deposition rates (kd) of ZnO-NPs rapidly decreased with increasing P/Zn molar ratio. In contrast, the solution pH had negligible effects on ZnO-NP transport behavior under phosphate-abundant condition (P/Zn: 4). The distinct effects may be explained by the energy interaction between ZnO-NPs and sand surface under different conditions. Interestingly, under phosphate-abundant condition (P/Zn: 4), solution pH could strongly affect the transport of Zn(2+) in the water-saturated sand. Overall, this study outlines the importance of taking account of phosphate into risk assessment of NPs in the environment. PMID:24355393

  9. Silica precipitation in acidic solutions: mechanism, pH effect, and salt effect.

    PubMed

    Gorrepati, Elizabeth A; Wongthahan, Pattanapong; Raha, Sasanka; Fogler, H Scott

    2010-07-01

    This study is the first to show that silica precipitation under very acidic conditions ([HCl] = 2-8 M) proceeds through two distinct steps. First, the monomeric form of silica is quickly depleted from solution as it polymerizes to form primary particles approximately 5 nm in diameter. Second, the primary particles formed then flocculate. A modified Smoluchowski equation that incorporates a geometric population balance accurately describes the exponential growth of silica flocs. Variation of the HCl concentration between 2 and 8 M further showed that polymerization to form primary particles and subsequent particle flocculation become exponentially faster with increasing acid concentration. The effect of salt was also studied by adding 1 M chloride salts to the solutions; it was found that salts accelerated both particle formation and growth rates in the order: AlCl(3) > CaCl(2) > MgCl(2) > NaCl > CsCl > no salt. It was also found that ionic strength, over cation identity, determines silica polymerization and particle flocculation rates. This research reveals that precipitation of silica products from acid dissolution of minerals can be studied apart from the mineral dissolution process. Thus, silica product precipitation from mineral acidization follows a two-step process--formation of 5 nm primary particles followed by particle flocculation--which becomes exponentially faster with increasing HCl concentration and with salts accelerating the process in the above order. This result has implications for any study of acid dissolution of aluminosilicate or silicate material. In particular, the findings are applicable to the process of acidizing oil-containing rock formations, a common practice of the petroleum industry where silica dissolution products encounter a low-pH, salty environment within the oil well. PMID:20536253

  10. Ice crystallization in ultrafine water-salt aerosols: nucleation, ice-solution equilibrium, and internal structure.

    PubMed

    Hudait, Arpa; Molinero, Valeria

    2014-06-01

    Atmospheric aerosols have a strong influence on Earth's climate. Elucidating the physical state and internal structure of atmospheric aqueous aerosols is essential to predict their gas and water uptake, and the locus and rate of atmospherically important heterogeneous reactions. Ultrafine aerosols with sizes between 3 and 15 nm have been detected in large numbers in the troposphere and tropopause. Nanoscopic aerosols arising from bubble bursting of natural and artificial seawater have been identified in laboratory and field experiments. The internal structure and phase state of these aerosols, however, cannot yet be determined in experiments. Here we use molecular simulations to investigate the phase behavior and internal structure of liquid, vitrified, and crystallized water-salt ultrafine aerosols with radii from 2.5 to 9.5 nm and with up to 10% moles of ions. We find that both ice crystallization and vitrification of the nanodroplets lead to demixing of pure water from the solutions. Vitrification of aqueous nanodroplets yields nanodomains of pure low-density amorphous ice in coexistence with vitrified solute rich aqueous glass. The melting temperature of ice in the aerosols decreases monotonically with an increase of solute fraction and decrease of radius. The simulations reveal that nucleation of ice occurs homogeneously at the subsurface of the water-salt nanoparticles. Subsequent ice growth yields phase-segregated, internally mixed, aerosols with two phases in equilibrium: a concentrated water-salt amorphous mixture and a spherical cap-like ice nanophase. The surface of the crystallized aerosols is heterogeneous, with ice and solution exposed to the vapor. Free energy calculations indicate that as the concentration of salt in the particles, the advance of the crystallization, or the size of the particles increase, the stability of the spherical cap structure increases with respect to the alternative structure in which a core of ice is fully surrounded by

  11. Aqueous Biphasic Systems Based on Salting-Out Polyethylene Glycol or Ionic Solutions: Strategies for Actinide or Fission Product Separations

    SciTech Connect

    Rogers, Robin D.; Gutowski, Keith E.; Griffin, Scott T.; Holbrey, John D.

    2004-03-29

    Aqueous biphasic systems can be formed by salting-out (with kosmotropic, waterstructuring salts) water soluble polymers (e.g., polyethylene glycol) or aqueous solutions of a wide range of hydrophilic ionic liquids based on imidazolium, pyridinium, phosphonium and ammonium cations. The use of these novel liquid/liquid biphases for separation of actinides or other fission products associated with nuclear wastes (e.g., pertechnetate salts) has been demonstrated and will be described in this presentation.

  12. Robust Benzo[g, h, i ]perylenetriimide Dye-Sensitized Electrodes in Air-Saturated Aqueous Buffer Solution.

    PubMed

    Chen, Hung-Cheng; Williams, René M; Reek, Joost N H; Brouwer, Albert M

    2016-04-11

    Highly electron deficient benzo[ghi]perylenetriimide (BPTI) chromophores were persistently anchored to a metal oxide electrode surface and reversible formation of their radical anions was shown in air-saturated aqueous buffer solution. Our results show a very low reaction-rate constant of BPTI(.-) with O2 (k=1.92±0.05×10(-2)  s(-1) ). BPTI is a robust chromophore that can be used as the electron acceptor in molecule-based artificial photosynthetic devices for direct water splitting in aqueous phase. PMID:26928886

  13. Effects of Temperature on Solute Transport Parameters in Differently-Textured Soils at Saturated Condition

    NASA Astrophysics Data System (ADS)

    Hamamoto, S.; Arihara, M.; Kawamoto, K.; Nishimura, T.; Komatsu, T.; Moldrup, P.

    2014-12-01

    Subsurface warming driven by global warming, urban heat islands, and increasing use of shallow geothermal heating and cooling systems such as the ground source heat pump, potentially causes changes in subsurface mass transport. Therefore, understanding temperature dependency of the solute transport characteristics is essential to accurately assess environmental risks due to increased subsurface temperature. In this study, one-dimensional solute transport experiments were conducted in soil columns under temperature control to investigate effects of temperature on solute transport parameters, such as solute dispersion and diffusion coefficients, hydraulic conductivity, and retardation factor. Toyoura sand, Kaolin clay, and intact loamy soils were used in the experiments. Intact loamy soils were taken during a deep well boring at the Arakawa Lowland in Saitama Prefecture, Japan. In the transport experiments, the core sample with 5-cm diameter and 4-cm height was first isotropically consolidated, whereafter 0.01M KCl solution was injected to the sample from the bottom. The concentrations of K+ and Cl- in the effluents were analyzed by an ion chromatograph to obtain solute breakthrough curves. The solute transport parameters were calculated from the breakthrough curves. The experiments were conducted under different temperature conditions (15, 25, and 40 oC). The retardation factor for the intact loamy soils decreased with increasing temperature, while water permeability increased due to reduced viscosity of water at higher temperature. Opposite, the effect of temperature on solute dispersivity for the intact loamy soils was insignificant. The effects of soil texture on the temperature dependency of the solute transport characteristics will be further investigated from comparison of results from differently-textured samples.

  14. 9 CFR 96.14 - Uncertified casings; disinfection with saturated brine solution.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... is necessary to agitate the solution occasionally by moving the casings. The tip of the recording thermometer should be located at a point which would be approximately at the bottom of the volume of...

  15. USING MINED SPACE FOR LONG-TERM RETENTION OF NONRADIOACTIVE HAZARDOUS WASTE. VOLUME 2. SOLUTION MINED SALT CAVERNS

    EPA Science Inventory

    This two-volume report assesses the current status of using mined-space for long-term retention of nonradioactive hazardous waste. Volume 2 expands the definition of mined space to include that created by solution mining of salt. This report examines the extent of salt deposits i...

  16. Molecular Thermodynamics for Swelling of a Mesoscopic Ionomer Gelin 1:1 Salt Solutions

    SciTech Connect

    Victorov, Alexey; Radke, Clayton; Prausnitz,John

    2005-06-15

    For a microphase-separated diblock copolymer ionic gel swollen in salt solution, a molecular-thermodynamic model is based on the self-consistent field theory in the limit of strongly segregated copolymer subchains. The geometry of microdomains is described using the Milner generic wedge construction neglecting the packing frustration. Thermodynamic functions are expressed analytically for gels of lamellar, bicontinuous, cylindrical and spherical morphologies. Molecules are characterized by chain composition, length, rigidity, degree of ionization, and by effective polymer-polymer and polymer-solvent interaction parameters. The model predicts equilibrium solvent uptakes and the equilibrium microdomain spacing for gels swollen in salt solutions. Results are given for details of the gel structure: distribution of mobile ions and polymer segments, and the electric potential across microdomains. Apart from effects obtained by coupling classical Flory-Rehner theory with Donnan equilibria, viz., increased swelling with polyelectrolyte charge and shrinking of gel upon addition of salt, the model predicts the effects of microphase morphology on swelling.

  17. Protein-protein and protein-salt interactions in aqueous protein solutions containing concentrated electrolytes

    SciTech Connect

    Curtis, R.A.; Blanch, H.W.; Prausnitz, J.M.

    1998-01-05

    Protein-protein and protein-salt interactions have been obtained for ovalbumin in solutions of ammonium sulfate and for lysozyme in solutions of ammonium sulfate, sodium chloride, potassium isothiocyanate, and potassium chloride. The two-body interactions between ovalbumin molecules in concentrated ammonium-sulfate solutions can be described by the DLVO potentials plus a potential that accounts for the decrease in free volume available to the protein due to the presence of the salt ions. The interaction between ovalbumin and ammonium sulfate is unfavorable, reflecting the kosmotropic nature of sulfate anions. Lysozyme-lysozyme interactions cannot be described by the above potentials because anion binding to lysozyme alters these interactions. Lysozyme-isothiocyanate complexes are strongly attractive due to electrostatic interactions resulting from bridging by the isothiocyanate ion. Lysozyme-lysozyme interactions in sulfate solutions are more repulsive than expected, possibly resulting from a larger excluded volume of a lysozyme-sulfate bound complex or perhaps, hydration forces between the lysozyme-sulfate complexes.

  18. RESULTS OF ANALYSES OF MACROBATCH 3 DECONTAMINATED SALT SOLUTION (DSS) COALESCER AND PRE-FILTERS

    SciTech Connect

    Peters, T.; Fondeur, F.; Fink, S.

    2012-06-13

    SRNL analyzed the pre-filter and Decontamination Salt Solution (DSS) coalescer from MCU by several analytical methods. The results of these analyses indicate that overall there is light to moderate solids fouling of both the coalescer and pre-filter elements. The majority of the solids contain aluminum, sodium, silicon, and titanium, in oxide and/or hydroxide forms that we have noted before. The titanium is presumably precipitated from leached, dissolved monosodium titanate (MST) or fines from MST at ARP, and the quantity we find is significantly greater than in the past. A parallel report discusses potential causes for the increased leaching rate of MST, showing that increases in free hydroxide concentration of the feed solutions and of chemical cleaning solutions lead to faster leaching of titanium.

  19. Iron salts in solid state and in frozen solutions as dosimeters for low irradiation temperatures.

    PubMed

    Martínez, T; Lartigue, J; Ramos-Bernal, S; Ramos, A; Mosqueira, G F; Negrón-Mendoza, A

    2005-01-01

    The aim of this work is to study the irradiation of iron salts in solid state (heptahydrated ferrous sulfate) and in frozen acid solutions. The study is focused on finding their possible use as dosimeters for low temperature irradiations and high doses. The analysis of the samples was made by UV-visible and Mössbauer spectroscopies. The output signal was linear from 0 to 10 MGy for the solid samples, and 0-600 Gy for the frozen solutions. The obtained data is reproducible and easy to handle. For these reasons, heptahydrate iron sulfate is a suitable dosimeter for low temperature and high irradiation doses, in solid state, and in frozen solution. PMID:15985374

  20. Faraday Discussion 160 Introductory Lecture: Interpreting and Predicting Hofmeister Salt Ion and Solute Effects on Biopolymer and Model Processes Using the Solute Partitioning Model

    PubMed Central

    Record, M. Thomas; Guinn, Emily; Pegram, Laurel; Capp, Michael

    2013-01-01

    Understanding how Hofmeister salt ions and other solutes interact with proteins, nucleic acids, other biopolymers and water and thereby affect protein and nucleic acid processes as well as model processes (e.g solubility of model compounds) in aqueous solution is a longstanding goal of biophysical research. Empirical Hofmeister salt and solute “m-values” (derivatives of the observed standard free energy change for a model or biopolymer process with respect to solute or salt concentration m3) are equal to differences in chemical potential derivatives: m-value = Δ(dμ2/dm3) = Δμ23 which quantify the preferential interactions of the solute or salt with the surface of the biopolymer or model system (component 2) exposed or buried in the process. Using the SPM, we dissect μ23 values for interactions of a solute or Hofmeister salt with a set of model compounds displaying the key functional groups of biopolymers to obtain interaction potentials (called α-values) that quantify the interaction of the solute or salt per unit area of each functional group or type of surface. Interpreted using the SPM, these α-values provide quantitative information about both the hydration of functional groups and the competitive interaction of water and the solute or salt with functional groups. The analysis corroborates and quantifies previous proposals that the Hofmeister anion and cation series for biopolymer processes are determined by ion-specific, mostly unfavorable interactions with hydrocarbon surfaces; the balance between these unfavorable nonpolar interactions and often-favorable interactions of ions with polar functional groups determine the series null points. The placement of urea and glycine betaine (GB) at opposite ends of the corresponding series of nonelectrolytes results from the favorable interactions of urea, and unfavorable interactions of GB, with many (but not all) biopolymer functional groups. Interaction potentials and local-bulk partition coefficients

  1. FT-IR and Raman spectroscopic analysis of hydrated cesium borates and their saturated aqueous solution

    NASA Astrophysics Data System (ADS)

    Zhihong, Liu; Bo, Gao; Mancheng, Hu; Shuni, Li; Shuping, Xia

    2003-10-01

    Hydrated cesium borates have been synthesized by the reaction of Cs 2CO 3 with H 3BO 3 aqueous solution. After reaction equilibria were reached, liquid and solid phases were separated and the FT-IR difference and Raman spectra of each phase were recorded, respectively. The assignments of the recorded FT-IR absorption frequencies and Raman shift are given. The main polyborate anions and their interaction in borate aqueous solution have been proposed. The relations between the existing forms of polyborate anions and the crystallizing solid phases, Cs 2B 4O 7·5H 2O and CsB 5O 8·4H 2O, have been gained.

  2. Properties of salt-saturated concrete and grout after six years in situ at the Waste Isolation Pilot Plant

    SciTech Connect

    Wakeley, L.D.; Harrington, P.T.; Weiss, C.A. Jr.

    1993-06-01

    Samples of concrete and grout were recovered from short boreholes in the repository floor at the Waste Isolation Pilot Plant more than six years after the concrete and grout were placed. Plugs from the Plug Test Matrix of the Plugging and Sealing Program of Sandia National Laboratories were overcored to include a shell of host rock. The cores were analyzed at the Waterways Experiment Station to assess their condition after six years of service, having potentially been exposed to those aspects of their service environment (salt, brine, fracturing, anhydrite, etc.) that could cause deterioration. Measured values of compressive strength and pulse velocity of both the grout and the concrete equaled or exceeded values from tests performed on laboratory-tested samples of the same mixtures at ages of one month to one year after casting. The phase assemblages had changed very little. Materials performed as intended and showed virtually no chemical or physical evidence of deterioration. The lowest values for strength and pulse velocity were measured for samples taken from the Disturbed Rock Zone, indicating the influence of cracking in this zone on the properties of enclosed seal materials. There was evidence of movement of brine in the system. Crystalline phases containing magnesium, potassium, sulfate, and other ions had been deposited on free surfaces in fractures and pilot holes. There was a reaction rim in the anhydrite immediately surrounding each recovered borehole plug, suggesting interaction between grout or concrete and host rock. However, the chemical changes apparent in this reaction rim were not reflected in the chemical composition of the adjacent concrete or grout. The grout and concrete studied here showed no signs of the deterioration found to have occurred in some parts of the concrete liner of the Waste Isolation Pilot Plant waste handling shaft.

  3. Decontamination of Dissolved Salt Solution from Tank 19F Using Duolite CS-100 and Amberlite IRC-718 Resins

    SciTech Connect

    Lee, L.M.

    2001-10-17

    In this study actual Savannah River Plant liquid supernate solutions were processed to refine and verify these synthetic solution studies. The main objectives were: (1) confirm high decontamination factors (DFs) for cesium-137 and strontium-90 using Duolite CS-100 and Amberlite IRC-718 ion exchange resins, (2) obtain DFs for other minor radioactive isotopes such as plutonium, technetium and ruthenium, (3) provide ion exchange elutriant containing cesium-137, strontium-90 and other radioactive isotopes for ''hot'' melter studies, (4) determine the quality of the decontaminated salt solution, and (5) provide actual decontaminated salt solution for saltcrete development programs.

  4. Evaluating Battery-like Reactions to Harvest Energy from Salinity Differences using Ammonium Bicarbonate Salt Solutions.

    PubMed

    Kim, Taeyoung; Rahimi, Mohammad; Logan, Bruce E; Gorski, Christopher A

    2016-05-10

    Mixing entropy batteries (MEBs) are a new approach to generate electricity from salinity differences between two aqueous solutions. To date, MEBs have only been prepared from solutions containing chloride salts, owing to their relevance in natural salinity gradients created from seawater and freshwater. We hypothesized that MEBs could capture energy using ammonium bicarbonate (AmB), a thermolytic salt that can be used to convert waste heat into salinity gradients. We examined six battery electrode materials. Several of the electrodes were unstable in AmB solutions or failed to produce expected voltages. Of the electrode materials tested, a cell containing a manganese oxide electrode and a metallic lead electrode produced the highest power density (6.3 mW m(-2) ). However, this power density is still low relative to previously reported NaCl-based MEBs and heat recovery systems. This proof-of-concept study demonstrated that MEBs could indeed be used to generate electricity from AmB salinity gradients. PMID:27030080

  5. Equilibrium, kinetic and thermodynamic study of cesium adsorption onto nanocrystalline mordenite from high-salt solution.

    PubMed

    Lee, Keun-Young; Park, Minsung; Kim, Jimin; Oh, Maengkyo; Lee, Eil-Hee; Kim, Kwang-Wook; Chung, Dong-Yong; Moon, Jei-Kwon

    2016-05-01

    In this study, the equilibrium, kinetics and thermodynamics of cesium adsorption by nanocrystalline mordenite were investigated under cesium contamination with high-salt solution, simulating the case of an operation and decommissioning of nuclear facilities or an accident during the processes. The adsorption rate constants were determined using a pseudo second-order kinetic model. The kinetic results strongly demonstrated that the cesium adsorption rate of nano mordenite is extremely fast, even in a high-salt solution, and much faster than that of micro mordenite. In the equilibrium study, the Langmuir isotherm model fit the cesium adsorption data of nano mordenite better than the Freundlich model, which suggests that cesium adsorption onto nano mordenite is a monolayer homogeneous adsorption process. The obtained thermodynamic parameters indicated that the adsorption involved a very stable chemical reaction. In particular, the combination of rapid particle dispersion and rapid cesium adsorption of the nano mordenite in the solution resulted in a rapid and effective process for cesium removal without stirring, which may offer great advantages for low energy consumption and simple operation. PMID:26683820

  6. Cosolute effect on crystallization of two dinucleotide complexes of bovine seminal ribonuclease from concentrated salt solutions

    NASA Astrophysics Data System (ADS)

    Sica, Filomena; Adinolfi, Salvatore; Vitagliano, Luigi; Zagari, Adriana; Capasso, Sante; Mazzarella, Lelio

    1996-10-01

    Two complexes of bovine seminal ribonuclease with dinucleotides, uridylyl(2'-5')adenosine (UpA) and 2'-deoxycytidylyl(3'-5')-2'-deoxyadenosine (d(CpA)), were crystallized under unusual conditions involving a liquid-liquid phase separation. This phenomenon was induced by adding small aliquots of organic cosolutes to highly concentrated ammonium sulfate solutions. The liquid-liquid interface acts as a source of nucleation centers for growth of large crystals. Among the cosolutes tested in these salt-mediated crystallizations, 2-methyl-2,4-pentanediol was found to be the most efficient.

  7. A perturbation solution for forced convection in a porous-saturated duct

    NASA Astrophysics Data System (ADS)

    Hooman, K.

    2008-01-01

    Fully developed forced convection through a porous medium bounded by two isoflux parallel plates is investigated analytically on the basis of a Brinkman-Forchheimer model. The matched asymptotic expansion method is applied for small values of the Darcy number. For the case of large Darcy number the solution for the Brinkman-Forchheimer momentum equation is found in terms of an asymptotic expansion. With the velocity distribution determined, the energy equation is solved using the same asymptotic technique. The results for limiting cases are found to be in good agreement with those available in the literature and the numerical results obtained here.

  8. Super-absorbency and phase transition of gels in physiological salt solutions

    NASA Astrophysics Data System (ADS)

    Zhang, Yong-Qing; Tanaka, Toyoichi; Shibayama, Mitsuhiro

    1992-11-01

    IONIC gels with the ability to absorb many times their dry weight of water have found widespread use as absorbents in medical, chemical and agricultural applications1. The dramatic swelling power of these super-absorbent gels results from both the electrostatic repulsion between the charges on the polymer chains, and the osmotic pressure of the counter-ions2. In salt solutions such as saline, urine or blood, however, excess Na+ and Cl- ions screen the polymer charges and eliminate the osmotic imbalance, effectively changing the properties of the material to that of a non-ionic gel3: this greatly diminishes the swelling power, and hence the utility of these materials under physiological conditions. Here we report the development of a system combining a non-ionic gel with ionized surfactants, which shows super-absorbent behaviour even in the presence of salt. In water, the hydrophobic gel facilitates the formation of spherical surfactant micelles, which mimic the charged sites of an ionic gel. As the salt concentration is increased, the micelles become rod-like, maintaining the electrostatic repulsion along the polymer chains and thereby preserving the swelling power of the gel.

  9. The activity-composition relationship of oxygen and hydrogen isotopes in aqueous salt solutions: II. Vapor-liquid water equilibration of mixed salt solutions from 50 to 100°C and geochemical implications

    NASA Astrophysics Data System (ADS)

    Horita, Juske; Cole, David R.; Wesolowski, David J.

    1993-10-01

    The difference between oxygen and hydrogen isotope activity and composition ratios of water in mixed salt solutions in the system Na-K-Mg-Ca-Cl-SO 4-H 2O was determined by means of a vaporliquid water equilibration method over the temperature range of 50 to 100°C. The observed isotope salt effects in complex mixed salt solutions to very high ionic strengths agree quantitatively with calculations based on the assumption of a simple additive property of the isotope salt effects of the individual salts in the solutions. SOFER and GAT (1972, 1975) and HORITA and GAT (1989) also observed that this simple mixing rule applies to synthetic and natural chloride-mixed salt solutions at room temperature. Equations to convert between the isotope activity and composition scales for brines and fractionation factors between brines and other substances are presented. For most geochemical interactions between brines and other phases (vapor, gases, minerals) such as evaporation/boiling, mineral precipitation, and mineral/rock alteration, the isotope activity scale should be used. The isotope composition scale, on the other hand, is most useful for studies of mixing of different brines and formation of brines by mineral dissolution. Misusage of the two isotopic scales of brines will, and probably in the literature has, lead to incorrect conclusions in many isotopic studies of brine-dominated systems (origin of brines, temperature of mineral formation, isotope ratios of fossil fluids).

  10. Development and field placement of an expansive salt-saturated concrete (ESC) for the Waste Isolation Pilot Plant (WIPP). Final report

    SciTech Connect

    Wakeley, L.D.; Walley, D.M.

    1986-09-01

    An expansive salt-saturated concrete (ESC) was proportioned for placement underground in halite rock at the Waste Isolation Pilot Plant (WIPP) site, near Carlsbad, New Mexico. Requirements for this concrete were: (1) to be chemically compatible with the host rock; (2) to remain pumpable for four hours: (3) to give net volume increase beginning at an early age, and continuing until creep closure of the salt assures sealing at the rock interface; and (4) to cure to a solid with extremely low permeability and fairly high strength. ESC was proportioned and placed underground at the WIPP in two successful field tests during FY 85 and FY 86. This report is the first of three reports about this concrete. It describes (1) the development of ESC in the laboratory, and (2) the mixture properties prior to final set. It summarizes field-placement activities in July 1985 and February 1986, when ESC was placed in test holes underground at the WIPP for two series of Small-Scale Seal Performance Tests (SSSPT). It gives data from tests of expansive behavior of the concrete at early ages and under simulated repository conditions. The second report will describe expansive behavior of ESC relative to several variables that could have an impact on its field performance and long-term stability, as determined during laboratory testing. It also will discuss possible explanations of the rather extraordinary suite of properties exhibited by ESC, as controlled by its chemical composition. The third report will describe laboratory studies of the mechanism of set retardation in a grout derived from this concrete.

  11. Effect of temperature on hydration kinetics and polymerization of tricalcium silicate in stirred suspensions of CaO-saturated solutions

    SciTech Connect

    Grant, Steven A. . E-mail: steven.a.grant@usace.army.mil; Boitnott, Ginger E.; Korhonen, Charles J.; Sletten, Ronald S.

    2006-04-15

    Tricalcium silicate was hydrated at 274, 278, 283, 298, and 313 K in stirred suspensions of saturated CaO solutions under a nitrogen-gas atmosphere until the end of deceleratory period. The suspension conductivities and energy flows were measured continuously. The individual reaction rates for tricalcium silicate dissolution, calcium silicate hydrate precipitation, and calcium hydroxide precipitation were calculated from these measurements. The results suggest that the proportion of tricalcium silicate dissolved was determined by the rate of tricalcium silicate dissolution and the time to very rapid calcium hydroxide precipitation. The time to very rapid calcium hydroxide precipitation was more sensitive to changes in temperature than was the rate of tricalcium silicate dissolution, so that the proportion of tricalcium silicate hydration dissolved by the deceleratory period increased with decreasing temperature. The average chain length of the calcium silicate hydrate ascertained by magic-angle spinning nuclear magnetic resonance spectroscopy increased with increasing temperature.

  12. Anomalous Solute Transport in Saturated Porous Media: Linking Transport Model Parameters to Electrical and Nuclear Magnetic Resonance Properties

    NASA Astrophysics Data System (ADS)

    Swanson, R. D.; Binley, A. M.; Keating, K.; France, S.; Osterman, G. K.; Day-Lewis, F. D.; Singha, K.

    2013-12-01

    The advection-dispersion equation fails to describe non-Fickian solute transport in saturated porous media, necessitating the use of other models. The dual-domain mass transfer (DDMT) model partitions the total porosity into mobile and less-mobile domains with solute exchange between the domains; consequently, the DDMT model can produce a better fit to breakthrough curves (BTCs) in systems defined by more- and less-mobile components. However, direct experimental estimation of DDMT model parameters such as rate of exchange and the mobile and less-mobile porosities remains elusive. Consequently, model parameters are often calculated purely as a model fitting exercise. There is a clear need for material characterization techniques that can offer some insight into the pore space geometrical arrangement, particularly if such techniques can be extended to the field scale. Here, we interpret static direct-current (DC) resistivity, complex resistivity (CR) and nuclear magnetic resonance (NMR) geophysical measurements in the characterization of mass transfer parameters. We use two different samples of the zeolite clinoptilolite, a material shown to demonstrate solute mass transfer due to a significant intragranular porosity, along with glass beads as a control. We explore the relation between geophysical and DDMT parameters in conjunction with supporting material characterization methods. Our results reveal how these geophysical measurements can offer some insight into the pore structures controlling the observed anomalous transport behavior.

  13. Ice nucleation of Snomax® particles below water vapor saturation: immersion freezing in concentrated solution droplets

    NASA Astrophysics Data System (ADS)

    Wex, Heike; Kanji, Zamin A.; Boose, Yvonne; Beyer, Alexander; Henning, Silvia; Augustin-Bauditz, Stefanie

    2015-04-01

    Heterogeneous ice nucleation has received an increasing amount of interest in the past years, as it initiates the ice phase in mixed phase clouds (MPCs) and, to some extent, also in cirrus clouds. The presence of ice influences cloud radiative properties and, for mixed phase clouds, also the formation of precipitation. Immersion freezing is thought to be the most important mechanism through which ice formation could take place in MPCs. Here, we examine the ice nucleation activity of biological ice nucleating particles (INP) derived from bacteria, namely, particles generated from Snomax® suspensions, both above and below water vapor saturation. During a measurement campaign in Leipzig, ice nucleation measurements were conducted with PINC (Portable Ice Nucleus Counter, Chou et al., 2011) and LACIS (Leipzig Aerosol Cloud Interaction Simulator, see e.g. Wex et al., 2014a). Immersion freezing measurements from PINC and LACIS were in agreement in the temperature regime for which both instruments operate reliably. Here, we will show that measurements done below water vapour saturation and above the deliquescence relative humidity of the Snomax® particles follow what would be expected for immersion freezing in concentrated solutions, similar to what was suggested for coated kaolinite particles in Wex et al. (2014b). Additionally, some measurements reported in the literature that were done in the water vapour sub-saturated regime will be evaluated based on the assumption made above, showing that at least some of the ice nucleation which previously was ascribed to deposition ice nucleation rather follows the behavior of immersion freezing in concentrated solutions. Literature: Chou, C., O. Stetzer, E. Weingartner, Z. Juranyi, Z. A. Kanji, and U. Lohmann (2011), Ice nuclei properties within a Saharan dust event at the Jungfraujoch in the Swiss Alps, Atmos. Chem. Phys., 11(10), 4725-4738, doi:10.5194/acp-11-4725-2011. Wex, H. et al. (2014a) Intercomparing different devices

  14. Evaluation of poly (aspartic acid sodium salt) as a draw solute for forward osmosis.

    PubMed

    Gwak, Gimun; Jung, Bokyung; Han, Sungsoo; Hong, Seungkwan

    2015-09-01

    Poly (aspartic acid sodium salt) (PAspNa) was evaluated for its potential as a novel draw solute in forward osmosis (FO). The inherent advantages of PAspNa, such as good water solubility, high osmotic pressure, and nontoxicity, were first examined through a series of physicochemical analyses and atomic-scale molecular dynamics simulations. Then, lab-scale FO tests were performed to evaluate its suitability in practical processes. Compared to other conventional inorganic solutes, PAspNa showed comparable water flux but significantly lower reverse solute flux, demonstrating its suitability as a draw solute. Moreover, fouling experiments using synthetic wastewater as a feed solution demonstrated that PAspNa reversely flowed to the feed side reduced inorganic scaling on the membrane active layer. The recyclability of PAspNa was studied using both nanofiltration (NF) and membrane distillation (MD) processes, and the results exhibited its ease of recovery. This research reported the feasibility and applicability of FO-NF or FO-MD processes using PAspNa for wastewater reclamation and brackish water desalination. PMID:26005789

  15. Simultaneous transport of synthetic colloids and a nonsorbing solute through single saturated natural fractures

    SciTech Connect

    Reimus, P.W.; Robinson, B.A.; Nuttall, H.E.; Kale, R.

    1994-09-01

    Tracer transport experiments involving colloids that showed little tendency to attach to rock surfaces and a nonsorbing solute (iodide) -were conducted in three different well-characterized natural fractures in tuff. The colloids always arrived earlier in the effluent than the iodide, which we believe is evidence of (1) hydrodynamic chromatography and/or (2) the fact that the colloids experience a smaller effective volume in the fracture because they diffuse too slowly to enter low-velocity regions (dead zones) along the rough fracture walls. The iodide also approached the inlet concentration in the effluent more slowly than the colloids, with the concentration at a given elution volume being greater at higher flow rates. By contrast, the rate of approach of the colloid concentration to the inlet concentration did not vary with flow rate. We attribute this behavior to matrix diffusion of the iodide, with the colloids being too large/nondiffusive to experience this phenomenon. Dispersion of all tracers was greatest in the fracture of widest average aperture and least in the fracture of narrowest aperture, which is consistent with Taylor dispersion theory. The tracer experiments were modeled/interpreted using a three-step approach that involved (1) estimating the aperture distribution in each fracture using surface profiling techniques, (2) predicting the flow field in the fractures using a localized parallel-plate approximation, and (3) predicting tracer transport in the fractures using particle-tracking techniques. Although considered preliminary at this time, the model results were in qualitative agreement with the experiments.

  16. Composite Properties of Polyimide Resins Made From "Salt-Like" Solution Precursors

    NASA Technical Reports Server (NTRS)

    Cano, Roberto J.; Weiser, Erik S.; SaintClair, Terry L.; Echigo, Yoshiaki; Kaneshiro, Hisayasu

    1997-01-01

    Recent work in high temperature materials at NASA Langley Research Center (LaRC (trademark)) have led to the development of new polyimide resin systems with very attractive properties. The majority of the work done with these resin systems has concentrated on determining engineering mechanical properties of composites prepared from a poly(amide acid) precursor. Three NASA Langley-developed polyimide matrix resins, LaRC (trademark) -IA, LaRC (trademark) -IAX, and LaRC (trademark) -8515, were produced via a salt-like process developed by Unitika Ltd. The 'salt-like' solutions (sixty-five percent solids in NMP) were prepregged onto Hexcel IM7 carbon fiber using the NASA LaRC Multipurpose Tape Machine. Process parameters were determined and composite panels fabricated. Mechanical properties are presented for these three intermediate modulus carbon fiber/polyimide matrix composites and compared to existing data on the same polyimide resin systems and IM7 carbon fiber manufactured via poly(amide acid) solutions (thirty-five percent solids in NMP). This work studies the effects of varying the synthetic route on the processing and mechanical properties of polyimide composites.

  17. Comparison of peak shape in hydrophilic interaction chromatography using acidic salt buffers and simple acid solutions.

    PubMed

    Heaton, James C; Russell, Joseph J; Underwood, Tim; Boughtflower, Robert; McCalley, David V

    2014-06-20

    The retention and peak shape of neutral, basic and acidic solutes was studied on hydrophilic interaction chromatography (HILIC) stationary phases that showed both strong and weak ionic retention characteristics, using aqueous-acetonitrile mobile phases containing either formic acid (FA), ammonium formate (AF) or phosphoric acid (PA). The effect of organic solvent concentration on the results was also studied. Peak shape was good for neutrals under most mobile phase conditions. However, peak shapes for ionised solutes, particularly for basic compounds, were considerably worse in FA than AF. Even neutral compounds showed deterioration in performance with FA when the mobile phase water concentration was reduced. The poor performance in FA cannot be entirely attributed to the negative impact of ionic retention on ionised silanols on the underlying silica base materials, as results using PA at lower pH (where their ionisation is suppressed) were inferior to those in AF. Besides the moderating influence of the salt cation on ionic retention, it is likely that salt buffers improve peak shape due to the increased ionic strength of the mobile phase and its impact on the formation of the water layer on the column surface. PMID:24813934

  18. Modeling reactive geochemical transport of concentrated aqueous solutions in variably saturated media

    SciTech Connect

    Zhang, Guoxiang; Zheng, Zuoping; Wan, Jiamin

    2004-01-28

    Concentrated aqueous solutions (CAS) have unique thermodynamic and physical properties. Chemical components in CAS are incompletely dissociated, especially those containing divalent or polyvalent ions. The problem is further complicated by the interaction between CAS flow processes and the naturally heterogeneous sediments. As the CAS migrates through the porous media, the composition may be altered subject to fluid-rock interactions. To effectively model reactive transport of CAS, we must take into account ion-interaction. A combination of the Pitzer ion-interaction and the ion-association model would be an appropriate way to deal with multiple-component systems if the Pitzer' parameters and thermodynamic data of dissolved components and the related minerals are available. To quantify the complicated coupling of CAS flow and transport, as well as the involved chemical reactions in natural and engineered systems, we have substantially extended an existing reactive biogeochemical transport code, BIO-CORE{sup 2D}{copyright}, by incorporating a comprehensive Pitzer ion-interaction model. In the present paper, the model, and two test cases against measured data were briefly introduced. Finally we present an application to simulate a laboratory column experiment studying the leakage of the high alkaline waste fluid stored in Hanford (a site of the U.S. Department of Energy, located in Washington State, USA). With the Pitzer ion-interaction ionic activity model, our simulation captures measured pH evolution. The simulation indicates that all the reactions controlling the pH evolution, including cation exchanges, mineral precipitation and dissolution, are coupled.

  19. A laboratory study of colloid and solute transport in surface runoff on saturated soil

    NASA Astrophysics Data System (ADS)

    Yu, Congrong; Gao, Bin; Muñoz-Carpena, Rafael; Tian, Yuan; Wu, Lei; Perez-Ovilla, Oscar

    2011-05-01

    SummaryColloids in surface runoff may pose risks to the ecosystems not only because some of them (e.g., pathogens) are toxic, but also because they may facilitate the transport of other contaminants. Although many studies have been conducted to explore colloid fate and transport in the environment, current understanding of colloids in surface runoff is still limited. In this study, we conducted a range of laboratory experiments to examine the transport behavior of colloids in a surface runoff system, made of a soil box packed with quartz sand with four soil drainage outlets and one surface flow outlet. A natural clay colloid (kaolinite) and a conservative chemical tracer (bromide) were applied to the system under a simulated rainfall event (64 mm/h). Effluent soil drainage and surface flow samples were collected to determine the breakthrough concentrations of bromide and kaolinite. Under the experimental conditions tested, our results showed that surface runoff dominated the transport processes. As a result, kaolinite and bromide were found more in surface flow than in soil drainage. Comparisons between the breakthrough concentrations of bromide and kaolinite showed that kaolinite had lower mobility than bromide in the subsurface flow (i.e., soil drainage), but behaved almost identical to bromide in the surface runoff. Student's t-test confirmed the difference between kaolinite and bromide in subsurface flow ( p = 0.02). Spearman's test and linear regression analysis, however, showed a strong 1:1 correlation between kaolinite and bromide in surface runoff ( p < 0.0001). Our result indicate that colloids and chemical solutes may behave similarly in overland flow on bare soils with limited drainage when surface runoff dominates the transport processes.

  20. Effect of the background solution and material composition on the transport of silver nanoparticles in saturated aquifer materials

    NASA Astrophysics Data System (ADS)

    Adrian, Yorck; Schneidewind, Uwe; Fernandez-Steeger, Tomas; Azzam, Rafig

    2016-04-01

    Engineered silver nanoparticles (AgNP) are used in various consumer products such as cloth or personal care products due to their antimicrobial properties (Benn et al., 2010). Their transport behavior in the environment is still under investigation. Previous studies have been focusing on the transport of AgNP in simple test systems with glass beads or soil materials (Braun et al., 2015), but studies investigating aquifer material are rare. However, the protection of fresh water resources in the subsurface is an important part in the protection of human health and the assurance of future economic activities. Therefore, expert knowledge regarding the transport and fate of engineered nanoparticles as potential contaminants in aquifers is essential. Within the scope of the research project NanoMobil funded by German Federal Ministry of Education and Research, the transport and retention behavior of AgNP in aquifer material was investigated under saturated conditions in laboratory columns for different flow velocities, ionic strengths (IS) and background solutions. The used aquifer material consisted mainly of quartz and albite. The quartz grains were partially coated with iron hydroxides and oxides. Furthermore, 1% hematite was present in the silicate dominated aquifer material. The experiments were conducted using NaNO3 and Ca(NO3)2 background solutions to examine the effects of monovalent and divalent cations on the transport of AgNP. Flow velocities in the columns were chosen to represent typical flow velocities of groundwater in the subsurface. For the experiments two mean grain sizes of 0.3 and 0.7 mm were used to investigate the effect of the grain size on the transport behavior. Particle concentration was measured using ICP-MS and particle size was determined using flow field-flow fractionation (FlFFF). HYDRUS-1D (Šimůnek et al., 2013) was used to elucidate the transport and retention processes of the AgNP in the aquifer material. The obtained results show

  1. Effect of Protein-Lipid-Salt Interactions on Sodium Availability in the Mouth and Consequent Perception of Saltiness: In Solutions.

    PubMed

    Yucel, Umut; Peterson, Devin G

    2015-09-01

    The influence of protein-sodium interactions on the availability of sodium in the aqueous phase of liquid samples and consequently on the perception of saltiness was investigated. The aqueous effluents of casein and casein emulsion-salt solutions were monitored for sodium availability from a tongue column system. In the aqueous protein-salt solutions, increasing the protein/salt ratio from 1:1 to 5:1 or 10:1 significantly decreased the initial salt concentration in the effluent and resulted in a higher salt concentration in the effluent over time. Sensory analysis was in agreement. Samples with increased protein were rated as having significantly lower initial saltiness and a higher salty aftertaste. However, when casein was formulated as an emulsion, the initial release of sodium in the effluent was enhanced (compared to nonemulsified protein). Increasing the emulsion interfacial area (more hydrophilic segments of the protein were structured into the aqueous phase) resulted in a higher salt concentration in the aqueous phase and greater perceived saltiness intensity. In summary, protein interactions, specifically ionic, were reported as food interactions that influence salt perception and provide a basis to develop higher flavor quality low-sodium food products. PMID:26255631

  2. Dynamics of salt playa polygons

    NASA Astrophysics Data System (ADS)

    Goehring, L.; Fourrière, A.

    2014-12-01

    In natural salt playa or in evaporation pools for the salt extraction industry, one can sometimes see surprising regular structures formed by ridges of salt. These ridges connect together to form a self-organized network of polygons one to two meters in diameter, which we call salt polygons. Here we propose a mechanism based on porous media convection of salty water in soil to explain the formation and the scaling of the salt polygons. Surface evaporation causes a steady upward flow of salty water, which can cause precipitation near the surface. A vertical salt gradient then builds up in the porous soil, with heavy salt-saturated water lying over the less salty source water. This can drive convection when a threshold is reached, given by a critical Rayleigh number of about 7. We suggest that the salt polygons are the surface expression of the porous medium convection, with salt crystallizing along the positions of the convective downwellings. To study this instability directly, we developed a 2D analogue experiment using a Hele-Shaw cell filled with a porous medium saturated with a salt solution and heated from above. We perform a linear stability analysis of this system, and find that it is unstable to convection, with a most unstable wavelength that is set by a balance between salt diffusion and water evaporation. The Rayleigh number in our experiment is controlled by the particle size of our model soil, and the evaporation rate. We obtain results that scale with the observation of natural salt polygons. Using dye, we observe the convective movement of salty water and find downwelling convective plumes underneath the spots where surface salt ridges form, as shown in the attached figure.

  3. Water Uptake by Mars Salt Analogs: An Investigation of Stable Aqueous Solutions Using Raman Microscopy

    NASA Astrophysics Data System (ADS)

    Nuding, Danielle L.

    Liquid water processes that may occur on the surface and near-subsurface of Mars have important implications for the present-day water cycle, habitability, and planetary protection policies. The presence of salts on Mars plays a role in surface-atmosphere interactions as salts enhance the soil's ability to retain water. This thesis explores the phase transitions of water upon interaction with Mars relevant salt analogs. Water uptake and loss properties of a single and complex Mars analog are examined using a Raman microscope equipped with an environmental cell. The effect of the hygroscopic salts on bacterial spores was evaluated with a focus on potential terrestrial contamination on outbound spacecraft and its influence on planetary protection concerns. Calcium perchlorate (Ca(ClO4)2) is a highly deliquescent salt that may exist on the surface of present-day Mars. Here, we quantify the deliquescent relative humidity (DRH) and efflorescent relative humidity (ERH) of Ca(ClO4)2 as a function of temperature (223 K to 273 K) to elucidate its behavior on the surface of Mars. Mars relevant temperature and relative humidity (RH) conditions were simulated and deliquescence (solid to aqueous) and efflorescence (aqueous to solid) phase transitions of Ca(ClO4)2 were characterized. Experimental DRH values were compared to a thermodynamic model for three hydration states of Ca(ClO 4)2. Calcium perchlorate was found to supersaturate, with lower ERH values than DRH values. Additionally, we conducted a 17-hour experiment to simulate a subsurface relative humidity and temperature diurnal cycle. This demonstrated that aqueous Ca(ClO4)2 solutions can persist without efflorescing for the majority of a martian sol, up to 17 hours under Mars temperature heating rates and RH conditions. Applying these experimental results to martian surface and subsurface heat and mass transfer models, we find that aqueous Ca(ClO4)2 solutions could persist for most of the martian sol under present

  4. Hydrology of the Bonneville Salt Flats, northwestern Utah, and simulation of ground-water flow and solute transport in the shallow-brine aquifer

    USGS Publications Warehouse

    Mason, James L.; Kipp, Kenneth L.

    1998-01-01

    This report describes the hydrologic system of the Bonneville Salt Flats with emphasis on the mechanisms of solute transport. Variable-density, three-dimensional computer simulations of the near-surface part of the ground-water system were done to quantify both the transport of salt dissolved in subsurface brine that leaves the salt-crust area and the salt dissolved and precipitated on the land surface. The study was designed to define the hydrology of the brine ground-water system and the natural and anthropogenic processes causing salt loss, and where feasible, to quantify these processes. Specific areas of study include the transport of salt in solution by ground-water flow and the transport of salt in solution by wind-driven ponds and the subsequent salt precipitation on the surface of the playa upon evaporation or seepage into the subsurface. In addition, hydraulic and chemical changes in the hydrologic system since previous studies were documented.

  5. The performance of a surface-applied corrosion inhibitor for the carbon steel in saturated Ca(OH){sub 2} solutions

    SciTech Connect

    Zheng, Haibing; Li, Weihua; Ma, Fubin; Kong, Qinglin

    2014-01-15

    In the present work, the performance of an amino alcohol based surface applied inhibitor was studied by the electrochemical techniques in saturated Ca(OH){sub 2} solutions. The surface morphology of the carbon steel was observed by scanning electron microscope, and the energy diffraction spectrum was also tested. Results showed that the inhibitor used in this work demonstrated obvious inhibition efficiency on the carbon steel in saturated Ca(OH){sub 2} solutions. The inhibition mechanism of the inhibitor lies in the quick adsorption of the active component on carbon steel surface.

  6. Self-organization of poly(ethylene oxide) on the surface of aqueous salt solutions.

    PubMed

    Fuchs, Christian; Hussain, Hazrat; Amado, Elkin; Busse, Karsten; Kressler, Joerg

    2015-01-01

    It is demonstrated that stable Langmuir films of poly(ethylene oxide) (PEO) can be formed up to surface pressures of 30 mN m(-1) when potassium carbonate K2CO3 is added to the aqueous subphase. Generally, PEO homopolymer cannot stay on the water surface at a surface pressure ≥10 mN m(-1) due to its high water solubility. To prepare stable monolayer films, PEO can be modified with hydrophobic moieties. However, by exploiting the salting out effect by adding certain salts (K2CO3 or MgSO4) into the aqueous subphase, not only very stable films but also unusual self-organization can be achieved by the PEO homopolymer on the surface of the aqueous solution. Thus, a series of OH-terminated PEOs is found to form a stable monolayer at K2CO3 concentrations of 2 M and above in the aqueous subphase, and the stability of the film increases with an increase in K2CO3 concentration. Hysteresis experiments are also carried out. During the phase transition induced by progressive compression, self-organization into well-defined domains with sizes in the micrometer range are observed, and with further compression and holding of the film for 30 min and above the microdomains transform into a crystalline morphology as visualized by Brewster angle microscopy. PMID:25269665

  7. Hydrogen generation in microbial reverse-electrodialysis electrolysis cells using a heat-regenerated salt solution.

    PubMed

    Nam, Joo-Youn; Cusick, Roland D; Kim, Younggy; Logan, Bruce E

    2012-05-01

    Hydrogen gas can be electrochemically produced in microbial reverse-electrodialysis electrolysis cells (MRECs) using current derived from organic matter and salinity-gradient energy such as river water and seawater solutions. Here, it is shown that ammonium bicarbonate salts, which can be regenerated using low-temperature waste heat, can also produce sufficient voltage for hydrogen gas generation in an MREC. The maximum hydrogen production rate was 1.6 m(3) H(2)/m(3)·d, with a hydrogen yield of 3.4 mol H(2)/mol acetate at a salinity ratio of infinite. Energy recovery was 10% based on total energy applied with an energy efficiency of 22% based on the consumed energy in the reactor. The cathode overpotential was dependent on the catholyte (sodium bicarbonate) concentration, but not the salinity ratio, indicating high catholyte conductivity was essential for maximizing hydrogen production rates. The direction of the HC and LC flows (co- or counter-current) did not affect performance in terms of hydrogen gas volume, production rates, or stack voltages. These results show that the MREC can be successfully operated using ammonium bicarbonate salts that can be regenerated using conventional distillation technologies and waste heat making the MREC a useful method for hydrogen gas production from wastes. PMID:22463373

  8. Light Emission from Porous Silicon Photoetched in Aqueous Alkali Salt Solutions

    NASA Astrophysics Data System (ADS)

    Adachi, Sadao; Miyazaki, Takayuki; Inoue, Kazufumi; Sodezawa, Shingo

    2007-07-01

    An interband-transition model was applied to explain the emission mechanism in porous silicon (PSi) fabricated by photoetching in aqueous HF and salt (NaF and KF) solutions. The HF-formed samples show a yellow photoluminescence band at ˜2 eV. The salt-formed samples, on the other hand, show an ultraviolet (UV) emission peak at ˜3.3 eV with a spectral width of ˜0.1 eV, together with a broad emission band at ˜2.7 eV. The broad emission bands at ˜2 and ˜2.7 eV can be explained by the quantum-mechanical confinement effect, i.e., a relaxation of the momentum conservation at and above the indirect-absorption edge (supra-EgID emission). This effect may also lead to a change in the E1 critical point (CP) from the two-dimensional M0 to the zero-dimensional CP with decreasing nanocrystalline size. The change in the E1-CP dimensionality makes possible an emission in the UV region with a narrow spectral width.

  9. Factors influencing the formation of polybromide monoanions in solutions of ionic liquid bromide salts.

    PubMed

    Easton, Max E; Ward, Antony J; Chan, Bun; Radom, Leo; Masters, Anthony F; Maschmeyer, Thomas

    2016-03-01

    Six different bromide salts - tetraethylammonium bromide ([N2,2,2,2]Br, Br), 1-ethyl-1-methylpiperidinium bromide ([C2MPip]Br, Br), 1-ethyl-1-methylpyrrolidinium bromide ([C2MPyrr]Br, Br), 1-ethyl-3-methylimidazolium bromide ([C2MIm]Br, Br), 1-ethylpyridinium bromide ([C2Py]Br, Br), and 1-(2-hydroxyethyl)pyridinium bromide ([C2OHPy]Br, Br) - were studied in regards to their capacity to form polybromide monoanion products on addition of molecular bromine in acetonitrile solutions. Using complementary spectroscopic and computational methods for the examination of tribromide and pentabromide anion formation, key factors influencing polybromide sequestration were identified. Here, we present criteria for the targeted synthesis of highly efficient bromine sequestration agents. PMID:26890026

  10. Electrophysical methods of separation of metal cations in the moving salts solution

    NASA Astrophysics Data System (ADS)

    Gofman, V. N.; Tuksov, I. V.; Timchenko, S. N.; Shamanin, I. V.; Poberezhnikov, A. D.; Kazaryan, M. A.

    2016-07-01

    The results of experiments on the excitation of the phenomenon of selective drift of solvated ions under the influence of an external "asymmetric" electric field to the circulating solution of calcium chloride and magnesium salts in a polar liquid dielectric - water are shown. The purpose of the experiments was to determine the influence of the field frequency and amplitude of the field strength on the excitation phenomenon, and the study of the operating characteristics of the testing apparatus - a dividing cell. The dependences of the separation efficiency of solvated cations from the frequency of the external field and the excitation threshold of the phenomenon from the field strength in the separation cell are defined.

  11. Molecular dynamics study of charged dendrimers in salt-free solution: Effect of counterions

    NASA Astrophysics Data System (ADS)

    Gurtovenko, Andrey A.; Lyulin, Sergey V.; Karttunen, Mikko; Vattulainen, Ilpo

    2006-03-01

    Polyamidoamine dendrimers, being protonated under physiological conditions, represent a promising class of nonviral, nanosized vectors for drug and gene delivery. We performed extensive molecular dynamics simulations of a generic model dendrimer in a salt-free solution with dendrimer's terminal beads positively charged. Solvent molecules as well as counterions were explicitly included as interacting beads. We find that the size of the charged dendrimer depends nonmonotonically on the strength of electrostatic interactions demonstrating a maximum when the Bjerrum length equals the diameter of a bead. Many other structural and dynamic characteristics of charged dendrimers are also found to follow this pattern. We address such a behavior to the interplay between repulsive interactions of the charged terminal beads and their attractive interactions with oppositely charged counterions. The former favors swelling at small Bjerrum lengths and the latter promotes counterion condensation. Thus, counterions can have a dramatic effect on the structure and dynamics of charged dendrimers and, under certain conditions, cannot be treated implicitly.

  12. Designing voltage multipliers with nanofluidic diodes immersed in aqueous salt solutions.

    PubMed

    Ramirez, P; Gomez, V; Verdia-Baguena, C; Nasir, S; Ali, M; Ensinger, W; Mafe, S

    2016-02-01

    Membranes with nanofluidic diodes allow the selective control of molecules in physiological salt solutions at ambient temperature. The electrical coupling of the membranes with conventional electronic elements such as capacitors suggests opportunities for the external monitoring of sensors and actuators. We demonstrate experimentally and theoretically the voltage multiplier functionality of simple electrical networks composed of membranes with conical nanopores coupled to load capacitors. The robust operation of half and full wave voltage multipliers is achieved in a broad range of experimental conditions (single pore and multipore membranes, electrolyte concentrations, voltage amplitudes, and solid-state capacitances). The designed voltage multipliers operate in the liquid state and can be used in sensing devices because different electrical, optical, and chemical inputs are known to modulate the individual nanofluidic diode resistances in the electrical network. PMID:26771033

  13. Micro-Arc oxidation of Ti in a solution of sulfuric acid and Ti +3 salt

    NASA Astrophysics Data System (ADS)

    Ragalevičius, Rimas; Stalnionis, Giedrius; Niaura, Gediminas; Jagminas, Arūnas

    2008-01-01

    A comparative study was performed on the behavior of titanium electrode in a sulfuric acid solution with and without Ti +3 during micro-arc oxidation under the constant current density control regime. The composition and microstructure of the obtained micro-arc films were analyzed using scanning electron microscopy, glancing-angle X-ray diffractometry, Raman and energy-dispersive X-ray spectroscopies. We have shown that addition of a Ti +3 salt extends the region of current densities ( ja) can be used for micro-arc oxidation of Ti and results in an obvious change of sparking behavior from extensive, large and long-played sparks to numerous, small and short sparks. As a consequence, the titania films formed in the Ti +3-containing solutions are relatively thick, more uniform, composed of almost pure crystalline anatase and rutile phases of TiO 2, and contain a network of evenly distributed small pores. It has also been shown that these films are promising for applications in catalysis, sensors and optoelectronics. The Raman spectra indicate that an increase in the electrolysis time of titanium in the Ti +3-containing solution leads to the increase in rutile content, as expected.

  14. Mechanical Behavior of Salt Caverns: Closed-Form Solutions vs Numerical Computations

    NASA Astrophysics Data System (ADS)

    Wang, Linlin; Bérest, Pierre; Brouard, Benoît

    2015-11-01

    Creep closure and structural stability of a cylindrical elongated cavern leached out from a salt formation are discussed. The Norton-Hoff creep law, or "power law", is used to capture the main features of salt rheological behavior. Two failure criteria are considered: (1) shear stresses must not be larger than a certain fraction of the mean stress (dilation criterion); and (2) the effective stress at the cavern wall (actual stress plus cavern fluid pressure) must not be tensile. The case of a brine-filled cavern whose pressure is kept constant is discussed first. It is proved that creep closure reaches a steady state such that stresses in the rock mass remain constant. However, decades are needed to reach such a state. During the transient phase that results from the slow redistribution of stresses in the rock mass, deviatoric stresses decrease at the vicinity of the cavern wall, and onset of dilation is less and less likely. At this point, the case of a rapid brine pressure increase, typical of a tightness test, is considered. It is proved that during such a swift pressure increase, cavern behavior is almost perfectly elastic; there is no risk of dilation onset. However, even when cavern pressure remains significantly smaller than geostatic, the effective stress at cavern wall can become tensile. These results, obtained through numerical computations, are confirmed by closed-form solutions obtained in the case of an idealized perfectly cylindrical cavern; these solutions provide a better insight into the main structural features of the behavior of the cavern.

  15. Effects of Solution Chemistry on the Retention and Dissolution of Silver Nanoparticles in Water-Saturated Porous Media

    NASA Astrophysics Data System (ADS)

    Mittelman, A.; Wang, Y.; Pennell, K. D.

    2011-12-01

    Potential health and environmental effects have been attributed to both silver nanoparticles (nAg) and the silver ion (Ag+), necessitating a thorough understanding of mechanisms governing the fate and transport of nAg in natural systems. Batch and column experiments were conducted to assess nAg transport, retention and dissolution kinetics as a function of pH, electrolyte and dissolved oxygen (DO) content. Batch experiments were performed at pH 4, 5.5 and 7, DO levels of <0.15 mg/L, 2mg/L and 8.9 mg/L, and with 10mM nitrate, acetate or borate as the background electrolyte. Batch solutions containing ca. 2 mg/L nanosilver were monitored regularly for 48 hours and analyzed for mean particle diameter, zeta potential, nanoparticle concentration and silver ion concentration. Silver nanoparticle dissolution increased with decreasing pH and with dissolved oxygen content. Increased aggregation and less negative zeta potential values (tending closer to the point of zero charge) indicate that acetate causes greater instability in nAg suspensions as compared with nitrate at the same ionic strength. Column experiments were performed in glass columns (11 cm length x 2.7 cm diameter) packed with washed 40-50 mesh Ottawa sand and saturated with a background electrolyte solution. Following a non-reactive tracer test, a three pore volume pulse of nAg suspension (ca. 3 mg/L silver) was introduced at a flow rate of 1.0 ml/min (pore water velocity of ca. 7.0 m/d), followed by three pore volumes of nanoparticle-free solution. Column experiments were conducted with 10mM sodium nitrate at pH 4 and 7 and under oxygen rich (DO = 8.9 mg/L) and lean (DO < 0.15 mg/L) conditions. Hyper-exponential retention profiles were observed, with the highest attachment measured at the column inlet. Under oxygen rich conditions, approximately 85% of the input nAg was retained in sand at pH 4, compared with 25% at pH 7. Consistent with batch experimental results, dissolution of retained nanoparticles

  16. Cross-diffusion-driven gravitational instability in a Hele-Shaw cell saturated with a ternary solution

    NASA Astrophysics Data System (ADS)

    Kim, Min Chan; Song, Kwang Ho

    2016-08-01

    The effect of cross diffusion on the onset of the gravitational instabilities in a Hele-Shaw cell saturated with a ternary solution is analyzed. Based on the linear stability theory, new stability equations are derived in the global domain and then transformed into the similar domain. These stability equations are solved by employing various methods such as an initial value problem approach and quasi-steady state approximations (QSSA's). Through the initial growth rate analysis without the QSSA, we prove that initially the system is unconditionally stable. However, the QSSA in the global domain showed that the system can be initially unstable for a certain condition. Based on the QSSA in the similar domain (QSSAζ), we obtain the critical time for the onset of instability motion. As expected, the higher |" separators=" δ 21 β | makes the system more unstable, i.e., accelerates the onset of instability motion; here δ21 and β represent the normalized cross diffusion coefficient and the ratio of densification coefficients, respectively. Based on the linear analysis, fully nonlinear analyses are also conducted by using the Fourier spectral method. The present nonlinear analyses show that the double-diffusive and diffusive-layer convection-type of instabilities are possible for the positive and negative δ21β-values, respectively. From the present nonlinear analysis, the system having δ22 > 1 prefers the instabilities with a larger wavelength than the system having δ22 < 1. Here δ22 is the normalized normal diffusion coefficient of component B.

  17. γ-Radiolysis of N 2O-saturated aqueous glycerol solutions: Product yields and free radical mechanism

    NASA Astrophysics Data System (ADS)

    Baugh, Peter J.; Moore, John S.; Norris, Alan F.; von Sonntag, Clemens

    The yields of products, glyceraldehyde (I), dihydroxyacetone (II), 3-hydroxypropanal (III), hydroxyacetone (IV), 2,3-bis(hydroxymethyl)-1,4-butandial (V), 1,2-bis(glycolyl)ethane (VI), 3-(glycolyl)-2-(hydroxymethyl)-propanal (VII), 2-(hydroxymethyl)-3, 4, 5-trihydroxy pentanal (VIII), 3-deoxyhexulose (IX), hexitol (X), 2-(hydroxymethyl)-pentitol (XI) and trimer (XII) formed during the γ-radiolysis of N 2O-saturated aqueous solutions containing glycerol have been quantitatively determined by gas liquid chromatography. It is evident that four radicals generated from the initial substrate participate in disproportionation, dimerisation and hydrogen abstraction reactions leading to these products. These radicals comprise two hydroxyalkyl radicals and their corresponding carbonyl-conjugated product radicals formed after water elimination. The initial radicals lead directly to products I, II, X and XI and the water-eliminated radicals to products III, IV, VI and VII. Products VIII and IX result from combination of the hydroxy-alkyl and carbonyl-conjugated radicals. Dimerisation and disproportionation of the hydroxy-alkyl radicals are favoured at higher dose rates while there is a reduction in water elemination and the products resulting. Hydrogen abstraction from glycerol by carbonyl-conjugated radicals in a chain mechanism is responsible for the large increase in yields of products III and IV when the initial substrate concentration is increased.

  18. Optimization of a PGSS (particles from gas saturated solutions) process for a fenofibrate lipid-based solid dispersion formulation.

    PubMed

    Pestieau, Aude; Krier, Fabrice; Lebrun, Pierre; Brouwers, Adeline; Streel, Bruno; Evrard, Brigitte

    2015-05-15

    The aim of this study was to develop a formulation containing fenofibrate and Gelucire(®) 50/13 (Gattefossé, France) in order to improve the oral bioavailability of the drug. Particles from gas saturated solutions (PGSS) process was chosen for investigation as a manufacturing process for producing a solid dispersion. The PGSS process was optimized according to the in vitro drug dissolution profile obtained using a biphasic dissolution test. Using a design of experiments approach, the effects of nine experimental parameters were investigated using a PGSS apparatus provided by Separex(®) (Champigneulles, France). Within the chosen experimental conditions, the screening results showed that the drug loading level, the autoclave temperature and pressure, the connection temperature and the nozzle diameter had a significant influence on the dissolution profile of fenofibrate. During the optimization step, the three most relevant parameters were optimized using a central composite design, while other factors remained fixed. In this way, we were able to identify the optimal production conditions that would deliver the highest level of fenofibrate in the organic phase at the end of the dissolution test. The closeness between the measured and the predicted optimal dissolution profiles in the organic phase demonstrated the validity of the statistical analyses. PMID:25796121

  19. Anomalous solute transport in saturated porous media: Relating transport model parameters to electrical and nuclear magnetic resonance properties

    NASA Astrophysics Data System (ADS)

    Swanson, Ryan D.; Binley, Andrew; Keating, Kristina; France, Samantha; Osterman, Gordon; Day-Lewis, Frederick D.; Singha, Kamini

    2015-02-01

    The advection-dispersion equation (ADE) fails to describe commonly observed non-Fickian solute transport in saturated porous media, necessitating the use of other models such as the dual-domain mass-transfer (DDMT) model. DDMT model parameters are commonly calibrated via curve fitting, providing little insight into the relation between effective parameters and physical properties of the medium. There is a clear need for material characterization techniques that can provide insight into the geometry and connectedness of pore spaces related to transport model parameters. Here, we consider proton nuclear magnetic resonance (NMR), direct-current (DC) resistivity, and complex conductivity (CC) measurements for this purpose, and assess these methods using glass beads as a control and two different samples of the zeolite clinoptilolite, a material that demonstrates non-Fickian transport due to intragranular porosity. We estimate DDMT parameters via calibration of a transport model to column-scale solute tracer tests, and compare NMR, DC resistivity, CC results, which reveal that grain size alone does not control transport properties and measured geophysical parameters; rather, volume and arrangement of the pore space play important roles. NMR cannot provide estimates of more-mobile and less-mobile pore volumes in the absence of tracer tests because these estimates depend critically on the selection of a material-dependent and flow-dependent cutoff time. Increased electrical connectedness from DC resistivity measurements are associated with greater mobile pore space determined from transport model calibration. CC was hypothesized to be related to length scales of mass transfer, but the CC response is unrelated to DDMT.

  20. Chain dimensions in free and immobilized brush states of polysulfobetaine in aqueous solution at various salt concentrations

    NASA Astrophysics Data System (ADS)

    Terayama, Y.; Arita, H.; Ishikawa, T.; Kikuchi, M.; Mitamura, K.; Kobayashi, M.; Yamada, N. L.; Takahara, A.

    2011-01-01

    The chain dimensions of free and immobilized polysulfobetaine in aqueous solution at various salt concentrations were investigated by size-exclusion chromatography with multiangle light scattering and neutron reflectivity measurement, respectively. The dependence of the z-average mean square radius of gyration (z1/2) on the weight-average molecular weight (Mw) of free poly(3-(N-2-methacryloyloxyethyl-N,N-dimethyl)ammonatopropanesulfo-nate) (MAPS) in aqueous solution at salt concentrations of 74, 100, 200, and 500 mM was described by the perturbed wormlike chain model using the chain stiffness parameter λ-1 the molar mass per unit contour length ML, and the excluded volume effect B. B increased from 0 to 1.8 nm with increasing salt concentration to 500 mM due to the screening of attractive electrostatic interaction between ammonium cations and sulfonyl anions by salt ions. The swollen structure of the poly(MAPS) brush in D2O changed from a shrunken state to a relatively extended state with increasing salt concentration from 0 to 500 mM NaCl/D2O solution. The thickness of the swollen poly(MAPS) brush in 500 mM NaCl/D2O was 9.0 times greater than 2z1/2 of free poly(MAPS) due to high osmotic pressure generated by the excluded volume effect of densely grafted polymer chains.

  1. Structure of salts solution in polar dielectric liquids and electrically induced separation of solvated ions

    NASA Astrophysics Data System (ADS)

    Shamanin, Igor V.; Kazaryan, Mishik A.; Sachkov, Victor I.

    2015-12-01

    The aim of study is to demonstrate that separation of solvated ions in solution of mix of salts under the action of external periodic electric field happens because of around ions there are formed clusters consisting of molecules of solvent and the sizes of such clusters have dimensions ~ 0.1 μm. In investigations the sizes of clusters theoretically were defined and experimentally value of frequency of external electric field which action excites the effect of separation of the solvated ions was defined. Experiments were done in the Technical Physics Chair of the National Research Tomsk Polytechnic University. At theoretical determination of the dimensions of clusters Poisson's equation was solved and was considered that polar molecules of solvent are oriented under the action of electric field of an ion. The chemical composition of samples of solutions was determined by means of the spectrophotometry and he X-ray excited fluorescent radiation analysis method. Theoretical estimates and results of experiments confirmed the assumption that clusters which are formed around ions in solutions have the dimensions ~ 0.1 μm. Results of investigation testify that placing of volume distributed electric charge of ion in dielectric liquid is accompanied by formation of the supramolecular particles, which we called "clusters", linear sizes of which is significantly more than first and second radiuses of solvation (~ 1 Angstrom) and reach size ~ 0.1 μm. At such sizes inertial properties of clusters and their natural frequencies give the chance to operate their movement by means of action of external electric field on solution.

  2. Transport and Retention of TiO2 Rutile Nanoparticles in Saturated Porous Media: Influence of Solution pH, Ionic Strength, and the Presence of Humic Acid

    EPA Science Inventory

    The influence of solution pH, ionic strength, and varying concentrations of the Suwannee River Humic Acid (SRHA) on the transport of titanium dioxide (TiO2, rutile) nanoparticle aggregates (nTiO2) in saturated porous media was investigated through systematically examining the tra...

  3. Transport, retention, and long-term release behavior of ZnO nanoparticle aggregates in saturated quartz sand: Role of solution pH and biofilm coating

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The transport, retention, and long-term fate of zinc oxide nanoparticles (ZnO-NPs) were investigated in saturated, bare and biofilm (Pseudomonas putida) coated sand packed columns. Almost complete retention of ZnO-NPs occurred in bare and biofilm coated sand when the influent solution pH was 9 and t...

  4. Cryochemical method for forming spherical metal oxide particles from metal salt solutions

    DOEpatents

    Tinkle, M.C.

    1973-12-01

    A method is described of preparing small metal oxide spheres cryochemically utilizing metal salts (e.g., nitrates) that cannot readily be dried and calcined without loss of sphericity of the particles. Such metal salts are cryochemically formed into small spheres, partially or completely converted to an insoluble salt, and dried and calcined. (Official Gazette)

  5. Adaptive resolution simulation of an atomistic DNA molecule in MARTINI salt solution

    NASA Astrophysics Data System (ADS)

    Zavadlav, J.; Podgornik, R.; Melo, M. N.; Marrink, S. J.; Praprotnik, M.

    2016-07-01

    We present a dual-resolution model of a deoxyribonucleic acid (DNA) molecule in a bathing solution, where we concurrently couple atomistic bundled water and ions with the coarse-grained MARTINI model of the solvent. We use our fine-grained salt solution model as a solvent in the inner shell surrounding the DNA molecule, whereas the solvent in the outer shell is modeled by the coarse-grained model. The solvent entities can exchange between the two domains and adapt their resolution accordingly. We critically asses the performance of our multiscale model in adaptive resolution simulations of an infinitely long DNA molecule, focusing on the structural characteristics of the solvent around DNA. Our analysis shows that the adaptive resolution scheme does not produce any noticeable artifacts in comparison to a reference system simulated in full detail. The effect of using a bundled-SPC model, required for multiscaling, compared to the standard free SPC model is also evaluated. Our multiscale approach opens the way for large scale applications of DNA and other biomolecules which require a large solvent reservoir to avoid boundary effects.

  6. Rubidium-87 NMR studies of rubidium salts and complexes with 18-crown-6 and cryptand-222 in solutions

    NASA Astrophysics Data System (ADS)

    Khazaeli, Sadegh; Dye, James L.; Popov, Alexander I.

    Rubidium-87 NMR measurements were used to study the behavior of the Rb + ion in water, methanol, and propylene carbonate solutions. In aqueous solutions the 87Rb chemical shift varies linearly with the mean activity of the salt. In methanol and propylene carbonate solutions the relationship is linear only at high salt concentrations. The resonance lines are broad and vary from ˜ 150 Hz (at half height) in water to ˜ 1000 Hz in propylene carbonate. Additions of macrocyclic ligands 18C6 and C222 to Rb + solutions in the three solvents result in further broadening of the resonance line so that variations in the resonance frequency cannot be measured with a reasonable precision.

  7. REAL-TIME MONITORING OF A SALT SOLUTION MINING CAVERN: FROM PRECURSORY SIGNS TO GENERAL COLLAPSE

    NASA Astrophysics Data System (ADS)

    Klein, E.; Contrucci, I.; Cao, N.; Bigarré, P.

    2009-12-01

    In order to improve our understanding in brutal large scale ground failure phenomenon, a salt solution mining cavern was instrumented in 2004 previously to its expected collapse as part of its mining scheme. A permanent early warning system was set up, including a high resolution microseismic monitoring network linked to a surface field displacement measurement system. The important amount of data collected during this 5 years experiment offered real-time insight of the evolution of the geological system. The complete data set recorded during the experiment made it possible to track with precision the main stages in the evolution of the cavern. The early signs of failure were detected by high resolution microseismic monitoring during spring 2008: a shift in microseismic background regime as well as recurrent microseismic episodes were undoubtedly associated to a general process of rock failure due to the salt cavern extending up to a critical size. This was accompanied by a few episodes of massive roof falls while the upper part of the overburden remained elastic, with no ground surface movement detected. During a second and last stage of evolution, on-line processing and analysis of a sudden intense microseismic activity allowed the interpretation of the rapid, energetic failure of a thin and very stiff bed rock underlying 120 meters deep. After this failure, the ground surface measurements indicated an irreversible acceleration of the subsidence up to the general collapse 24 hours later. As it will be shown, the in-depth analysis of the whole data set enables to characterize the dynamic process of rupture and its associated precursory signs. It provides also essential knowledge and feedback experience for operational monitoring of underground operations carried out on other sensitive mining sites.

  8. Estimation of salt water upconing using a steady-state solution for partial completion of a pumped well.

    PubMed

    Garabedian, Stephen P

    2013-01-01

    A new steady-state analytical solution to the two-dimensional radial-flow equation was developed for drawdown (head) conditions in an aquifer with constant transmissivity, no-flow conditions at the top and bottom, constant head conditions at a known radial distance, and a partially completed pumping well. The solution was evaluated for accuracy by comparison to numerical simulations using MODFLOW. The solution was then used to estimate the rise of the salt water-fresh water interface (upconing) that occurs under a pumping well, and to calculate the critical pumping rate at which the interface becomes unstable, allowing salt water to enter the pumping well. The analysis of salt water-fresh water interface rise assumed no significant effect on upconing by recharge; this assumption was tested and supported using results from a new steady-state analytical solution developed for recharge under two-dimensional radial-flow conditions. The upconing analysis results were evaluated for accuracy by comparison to those from numerical simulations using SEAWAT for salt water-fresh water interface positions under mild pumping conditions. The results from the equation were also compared with those of a published numerical sharp-interface model applied to a case on Cape Cod, Massachusetts. This comparison indicates that estimating the interface rise and maximum allowable pumping rate using the analytical method will likely be less conservative than the maximum allowable pumping rate and maximum stable interface rise from a numerical sharp-interface model. PMID:23336341

  9. The material flow of salt

    SciTech Connect

    Kostick, D.S. )

    1993-01-01

    Salt (NaCl) is a universal mineral commodity used by virtually every person in the world. Although a very common mineral today, at one time it was considered as precious as gold in certain cultures. This study traces the material flow of salt from its origin through the postconsumer phase of usage. The final disposition of salt in the estimated 14,000 different uses, grouped into several macrocategories, is traced from the dispersive loss of salt into the environment to the ultimate disposal of salt-base products into the waste stream after consumption. The base year for this study is 1990, in which an estimated 196 million short tons of municipal solid waste was discarded by the US population. Approximately three-fourths of domestic salt consumed is released to the environment and unrecovered while about one-fourth is discharged to landfills and incinerators as products derived from salt. Cumulative historical domestic production, trade, and consumption data have been compiled to illustrate the long-term trends within the US salt industry and the cumulative contribution that highway deicing salt has had on the environment. Salt is an important component of drilling fluids in well drilling. It is used to flocculate and to increase the density of the drilling fluid in order to overcome high down-well gas pressures. Whenever drilling activities encounter salt formations, salt is added to the drilling fluid to saturate the solution and minimize the dissolution within the salt strata. Salt is also used to increase the set rate of concrete in cemented casings. This subsector includes companies engaged in oil, gas, and crude petroleum exploration and in refining and compounding lubricating oil. It includes SIC major groups 13 and 29. 13 refs., 14 figs., 6 tabs.

  10. The on-line removal of non-regenerable salts from amine solutions using the UCARSEP{reg_sign} Process

    SciTech Connect

    Burns, D.; Gregory, R.A.

    1995-11-01

    Amine unit contamination with non-regenerable salts, whether as a result of acid or inorganic salt incursion, or solvent degradation, is a common industry problem. In MEA systems this is usually addressed by the use of a reclaimer but this is not a practical solution for DEA, MDEA or formulated solvents. Similarly, the old approach of purging solvent is no longer economically or environmentally justifiable. Neutralization of amine salts with a strong base can significantly prolong the useful life of the amine solution but eventually some of the salt may have to be removed, especially if mechanical losses are low. Electrodialysis (ED) has recently been applied to this problem and has been found to overcome many of the disadvantages of vacuum distillation and ion exchange technologies, both of which have been used in recent years for solvent clean-up. Union Carbide adapted ED technology to the unique conditions encountered in an amine system and developed the UCARSEP{reg_sign} Process. A mobile UCARSEP{reg_sign} unit has been built to achieve on-line salt removal rates of 40 lbmol/day (about 3,300 lb/day). This has been successfully used to clean up UCARSOL{reg_sign} solvents as well as DEA. Case studies are presented and the relative merits of this and other clean-up options are discussed.

  11. SAVANNAH RIVER SITE INCIPIENT SLUDGE MIXING IN RADIOACTIVE LIQUID WASTE STORAGE TANKS DURING SALT SOLUTION BLENDING

    SciTech Connect

    Leishear, R.; Poirier, M.; Lee, S.; Steeper, T.; Fowley, M.; Parkinson, K.

    2011-01-12

    This paper is the second in a series of four publications to document ongoing pilot scale testing and computational fluid dynamics (CFD) modeling of mixing processes in 85 foot diameter, 1.3 million gallon, radioactive liquid waste, storage tanks at Savannah River Site (SRS). Homogeneous blending of salt solutions is required in waste tanks. Settled solids (i.e., sludge) are required to remain undisturbed on the bottom of waste tanks during blending. Suspension of sludge during blending may potentially release radiolytically generated hydrogen trapped in the sludge, which is a safety concern. The first paper (Leishear, et. al. [1]) presented pilot scale blending experiments of miscible fluids to provide initial design requirements for a full scale blending pump. Scaling techniques for an 8 foot diameter pilot scale tank were also justified in that work. This second paper describes the overall reasons to perform tests, and documents pilot scale experiments performed to investigate disturbance of sludge, using non-radioactive sludge simulants. A third paper will document pilot scale CFD modeling for comparison to experimental pilot scale test results for both blending tests and sludge disturbance tests. That paper will also describe full scale CFD results. The final paper will document additional blending test results for stratified layers in salt solutions, scale up techniques, final full scale pump design recommendations, and operational recommendations. Specifically, this paper documents a series of pilot scale tests, where sludge simulant disturbance due to a blending pump or transfer pump are investigated. A principle design requirement for a blending pump is UoD, where Uo is the pump discharge nozzle velocity, and D is the nozzle diameter. Pilot scale test results showed that sludge was undisturbed below UoD = 0.47 ft{sup 2}/s, and that below UoD = 0.58 ft{sup 2}/s minimal sludge disturbance was observed. If sludge is minimally disturbed, hydrogen will not be

  12. Using Hydrus-1D to Predict Solute Conservative Tracer Transfer from Initially Saturated Soil into the Surface Runoff Water underwith Controlled Drainage Condition

    NASA Astrophysics Data System (ADS)

    Tong, J.; Yang, J.; Hu, B.

    2013-12-01

    In this paper, a mixing layer theory is coupled with the Hydrus-1D to predict solute transfer from an initially saturated soil into surface runoff water under a controlled drainage condition with low infiltration rate, and various ponding waterwith the increasing depths of the ponding water on the soil surface before the surface runoff. A sand experiment is used as the reference experiment to identify the parameters for the water flow model and solute transfer model with increasing mixing layer depth after the surface runoff water. Based on these identified parameters andan increasing depth of the mixing layer, the model well predicts the experimental results, and much better than the a simulation results by thewith a constant mixing layer depth under the controlled drainage without drainage theory. The model is also applied to another initially saturated sand experiment under the controlled drainage water condition, and the simulation resultsdata agree well with the observed data. These results suggest that the model can efficiently simulate the solute transfer from the initially saturated soil into the surface runoff water. It is found from this study that with the increase of the surface runoff time or/and the decrease of the mixing layer, the solute loss in the mixing layer before the surface runoff will increase, the solute source in the mixing layer for the surface runoff water will decrease after the surface runoff and the increase rate of the mixing layer depth will increase. Simple sketch of the model Hydraulic parameters in the reference sand experiment

  13. The Arsenic Cycle in Searles Lake, California: An Arsenic-Rich, Salt-Saturated Soda Lake. II. Isolation of Arsenic-Metabolizing Microbes.

    NASA Astrophysics Data System (ADS)

    Switzer Blum, J.; Hoeft, S. E.; Stolz, J. F.; Langley, S.; Beveridge, T. J.; Kulp, T. R.; Oremland, R. S.

    2004-12-01

    The motivation for isolating arsenic-metabolizing prokaryotes from Searles Lake was to characterize the physiology of microbes that can cope simultaneously with at least 3 environmental extremes: saturating salt concentration, high pH, and high dissolved inorganic arsenic. A secondary motivation was to find extremely halophilc Archaea that could respire As(V), as this has only been reported for the Crenarchaea. Enrichment cultures of arsenate [As(V)]-respirers were established by inoculating Searles Lake mud into an anaerobic, alkaline (pH = 9.8) artificial medium containing 346 g/L dissolved salts, with lactate as the electron donor and As(V) as the electron acceptor. After about 6 months of bi-weekly transfers, the enrichment was purified by serial dilution, with the highest growth-positive dilution tube exhibiting motile cells having uniform morphology (curved rods). This culture, strain SLAS-1, grew by oxidizing lactate to acetate plus carbon dioxide while reducing As(V) to arsenite [As(III)]. The doubling time was 48 hours at 346 g/L salinity, and nearly equivalent growth rates were observed over a salinity range of 200 to 346 g/l, with no growth evident below 200 g/L. The pH range was 8.5 to 10, with an optimum at 9.5. Strain SLAS-1 has an unusual motility that can be characterized as a "fish-like" swimming motion. Thin section electron micrographs revealed the presence of an internal cytoplasmic filament that runs the full length of the microorganism. We suggest that this filament may be involved in cellular motility. However, taxonomic classification of SLAS-1 made by 16S rRNA gene sequences aligned it in the order Haloanaerobacteriales of the Domain Bacteria. In a further effort to isolate haloalkaliphilic Archaea, a similar enrichment strategy was employed as above, but cell-wall antibiotics were added to the medium to discourage the growth of Bacteria. An enrichment culture, designated Serl-Ab, was established that oxidized lactate to acetate plus carbon

  14. Analysis of saturated solar pond characteristics. Final report, October 1, 1979-April 30, 1981

    SciTech Connect

    Ochs, T.; Stojanoff, C.G.; Day, D.L.; Eckert, E.; Langeliers, J.; Wruck, D.

    1981-05-01

    The actual phenomena taking place in the saturated pond are studied. Experimental procedures for solar ponds are presented. In an attempt to summarize the physical properties of salt solutions an exhaustive literature search was conducted. The first part consists of basic definitions of terms and a summary of the properties of pure water. Data are tabulated on a number of binary aqueous solutions (one salt and water). (MHR)

  15. Experimental study of natural convection melting of ice in salt solutions

    SciTech Connect

    Fang, L.J.; Cheung, F.B.; Linehan, J.H.; Pedersen, D.R.

    1984-01-01

    The solid-liquid interface morphology and the micro-physical process near the moving phase boundary during natural convection melting of a horizontal layer of ice by an overlying pool of salt solution were studied experimentally. A cathetometer which amplifies the interface region was used to measure the ice melting rate. Also measured were the temperature transients of the liquid pool. Within the temperature and the density ratio ranges explored, the ice melting rate was found to be very sensitive to the ratio of pool-to-ice melt density but independent of pool-to-ice temperature difference. By varying the density ratio, three different flow regimes and morphologies of the solid-liquid interface were observed, with melt streamers emanating from the crests of the wavy interface into the pool in all three cases. The measured wavelengths (spacing) between the streamers for four different pairs of materials were correlated with the density ratio and found to agree favorably with the predictions of Taylor instability theory.

  16. Salt Solutions in Carbon Nanotubes: The Role of Cation- π Interactions

    NASA Astrophysics Data System (ADS)

    Pham, Tuan Anh; Mortuza, Golam; Wood, Brandon; Lau, Edmond; Ogitsu, Tadashi; Buchsbaum, Steven; Siwy, Zuzanna; Fornasiero, Francesco; Schwegler, Eric

    Understanding the structure of aqueous electrolytes at interfaces is essential for predicting and optimizing device performances for a wide variety of emerging energy and environmental technologies. In this work, we investigate the structure of two common salt solutions, NaCl and KCl, at a hydrophobic interface within narrow carbon nanotubes (CNTs). Using a combination of first-principles and classical molecular dynamics simulations, we find that the solvation structure of the cations in the CNTs can deviate substantially from the conventional weakly interacting hydrophobic picture. Instead, interactions between solvated ions and the π-orbitals of the CNTs are found to play a critically important role, with the ion solvation structure ultimately determined by a subtle interplay between cation- π interactions and the intrinsic flexibility of the solvation shell. In the case of K+, these effects result in an unusually strong propensity to partially desolvate and reside closer to the carbon wall than either Na+ and Cl-, in sharp contrast to the known ion ordering at the water-vapor interface. This work was performed under the auspices of the U.S. Department of Energy by LLNL under Contract DE-AC52-07NA27344.

  17. In vitro corrosion of ZEK100 plates in Hank's Balanced Salt Solution

    PubMed Central

    2012-01-01

    Background In recent years magnesium alloys have been intensively investigated as potential resorbable materials with appropriate mechanical and corrosion properties. Particularly in orthopedic research magnesium is interesting because of its mechanical properties close to those of natural bone, the prevention of both stress shielding and removal of the implant after surgery. Methods ZEK100 plates were examined in this in vitro study with Hank's Balanced Salt Solution under physiological conditions with a constant laminar flow rate. After 14, 28 and 42 days of immersion the ZEK100 plates were mechanically tested via four point bending test. The surfaces of the immersed specimens were characterized by SEM, EDX and XRD. Results The four point bending test displayed an increased bending strength after 6 weeks immersion compared to the 2 week group and 4 week group. The characterization of the surface revealed the presence of high amounts of O, P and Ca on the surface and small Mg content. This indicates the precipitation of calcium phosphates with low solubility on the surface of the ZEK100 plates. Conclusions The results of the present in vitro study indicate that ZEK100 is a potential candidate for degradable orthopedic implants. Further investigations are needed to examine the degradation behavior. PMID:22413949

  18. Protein-salt binding data from potentiometric titrations of lysozyme in aqueous solutions containing KCl

    SciTech Connect

    Engmann, J.; Blanch, H.W.; Prausnitz, J.M. |

    1997-03-01

    An existing method for potentiometric titrations of proteins was improved, tested and applied to titrations of the enzyme hen-egg-white lysozyme in aqueous solutions containing KCl at ionic strengths from 0.1 M to 2.0 M at 25 C. Information about the protein`s net charge dependence on pH and ionic strength were obtained and salt binding numbers for the system were calculated using a linkage concept. For the pH range 2.5--11.5, the net charge slightly but distinctly increases with increasing ionic strength between 0.1 M and 2.0 M. The differences are most distinct in the pH region below 5. Above pH 11.35, the net charge decreases with increasing ionic strength. Preliminary calculation of binding numbers from titration curves at 0.1 M and 1.0 M showed selective association of chloride anions and expulsion of potassium ions at low pH. Ion-binding numbers from this work will be used to evaluate thermodynamic properties and to correlate crystallization or precipitation phase-equilibrium data in terms of a model based on the integral-equation theory of fluids which is currently under development.

  19. Synergistic effects of inorganic salt and surfactant on phenanthrene removal from aqueous solution by sediment.

    PubMed

    Zhang, Xiaoyan; Wu, Yaoguo; Hu, Sihai; Lu, Cong

    2014-01-01

    The economic and effective application of surfactant enhanced remediation (SER) technology in a sediment-freshwater/saline water system was investigated by batch method using the combined effects of inorganic salt (sodium chloride, NaCl) and anionic surfactant (sodium dodecylbenzene sulfonate (SDBS)) on phenanthrene (PHE) removal via sorption by sediment. In all cases, PHE sorption followed a linear equation and partition as the main mechanism for PHE removal from aqueous solution. Separate addition of SDBS (2 mmol L(-1)) and NaCl (2-100 mmol L(-1)) moderately enhanced PHE removal, while with their combined addition the enhancement was substantial, and the removal efficiency achieved a peak of 92.8%. The combined effect expressed a synergy, and the sorption enhancement increased by factors of 2.7, 3.2 and 3.4 when compared with the sum of the separate entities at elevated salinity. This was because the sorbed SDBS, with increasing amount and a high packing conformation at elevated salinity, outcompeted aqueous SDBS for PHE partition. Moreover, a combination of 2 mmol L(-1) SDBS and 2 mmol L(-1) NaCl was optimal for PHE removal. Therefore, SER technology appears more effective for PHE removal in saline water than in freshwater, and preliminary water quality monitoring is essential for economic and efficient SER application. PMID:25353936

  20. Influence and hydrolysis kinetics in titanyl sulfate solution from the sodium hydroxide molten salt method

    NASA Astrophysics Data System (ADS)

    Wang, Weijing; Chen, Desheng; Chu, Jinglong; Li, Jie; Xue, Tianyan; Wang, Lina; Wang, Dong; Qi, Tao

    2013-10-01

    Hydrated titanium dioxide (HTD) was precipitated by thermal hydrolysis in purified titanyl sulfate solution (TSS) obtained through the sodium hydroxide molten salt clean method. Various factors including the stirring speed and initial concentrations of TiOSO4, sulfuric acid, and sodium ion were studied. The main influence factors in the hydrolysis process were the initial concentrations of TiOSO4 and sulfuric acid. Contrary to the ferrous ion, the sodium ion improved the ionic activity of Ti4+, but did not decrease the crystal size. The Boltzman growth model (x=A2+(A1-A2)/{1+exp[(t-t0)/dt)]}, which focuses on two main parameters (CTiOSO4 and CH2SO4), fits the hydrolysis process well with R2>0.97. An increase in sulfuric acid concentration negatively affected the hydrolysis rates and the value of A2, while t0 increased. An increase in titanyl sulfate concentration directly reduced the hydrolysis rates and particle size of HTD, contrary to the trend for the value of t0. A simulation software called 1stopt was used to observe the relationship between Z (A1, A2, t0, dt) and a, b (CTiO2 and CH2SO4).

  1. Extreme ductile deformation of fine-grained salt by coupled solution-precipitation creep and microcracking: Microstructural evidence from perennial Zechstein sequence (Neuhof salt mine, Germany)

    NASA Astrophysics Data System (ADS)

    Závada, Prokop; Desbois, Guillaume; Schwedt, Alexander; Lexa, Ondrej; Urai, Janos L.

    2012-04-01

    Microstructural study revealed that the ductile flow of intensely folded fine-grained salt exposed in an underground mine (Zechstein-Werra salt sequence, Neuhof mine, Germany) was accommodated by coupled activity of solution-precipitation (SP) creep and microcracking of the halite grains. The grain cores of the halite aggregates contain remnants of sedimentary microstructures with straight and chevron shaped fluid inclusion trails (FITs) and are surrounded by two concentric mantles reflecting different events of salt precipitation. Numerous intra-granular or transgranular microcracks originate at the tips of FITs and propagate preferentially along the interface between sedimentary cores and the surrounding mantle of reprecipitated halite. These microcracks are interpreted as tensional Griffith cracks. Microcracks starting at grain boundary triple junctions or grain boundary ledges form due to stress concentrations generated by grain boundary sliding (GBS). Solid or fluid inclusions frequently alter the course of the propagating microcracks or the cracks terminate at these inclusions. Because the inner mantle containing the microcracks is corroded and is surrounded by microcrack-free outer mantle, microcracking is interpreted to reflect transient failure of the aggregate. Microcracking is argued to play a fundamental role in the continuation and enhancement of the SP-GBS creep during halokinesis of the Werra salt, because the transgranular cracks (1) provide the ingress of additional fluid in the grain boundary network when cross-cutting the FITs and (2) decrease grain size by splitting the grains. More over, the ingress of additional fluids into grain boundaries is also provided by non-conservative grain boundary migration that advanced into FITs bearing cores of grains. Described readjustments of the microstructure and mechanical and chemical feedbacks for the grain boundary diffusion flow in halite-brine system are proposed to be comparable to other rock-fluid or

  2. Simulating water flow, heat and solute transport and biogeochemistry in variably-saturated porous media using HP1

    NASA Astrophysics Data System (ADS)

    Jacques, Diederik; Simunek, Jirka; Mallants, Dirk; van Genuchten, Rien

    2010-05-01

    Coupling physical and biogeochemical processes within one integrated numerical simulator provides a process-based tool for investigating the fate of contaminants as affected by changing hydrologic regimes and geochemical conditions. The numerical simulator HP1 attempts to bridge these two interactive processes. The code is especially geared for variably-saturated conditions, thus serving as a powerful tool for vadose zone research and engineering applications. HP1 extends the capabilities of HYDRUS-1D to simulate physical soil processes by including the capabilities of PHREEQC to account for biogeochemical processes, all embedded in a user-friendly windows interface. The HP1 reactive transport simulator was obtained by weak, non-iterative coupling of HYDRUS-1D and PHREEQC-2. HP1 is free software and can be obtained at http://www.pc-progress.com as part of HYDRUS-1D. A detailed account is given of the new features and processes that were recently incorporated in HP1: (i) full implementation of HP1 into the graphical user interface of HYDRUS-1D, (ii) dynamic changes in porosity, permeability and tortuosity when minerals dissolve or precipitate, and (iii) diffusion of gas components in the gaseous phase. The implementation of the porosity-permeability-tortuosity changes was benchmarked against results from the MIN3P code. HP1 users can implement their own porosity-permeability and porosity-tortuosity relationships using BASIC statements in the input file. Additionally, hydraulic conductivity and pressure head scaling factors can now also vary with time depending upon the geochemical state variables. An example is further presented in which HP1 is coupled with the model-independent optimization tool UCODE_2005 (Poeter et al., 2005) . The resulting software allows thermodynamic, kinetic and geochemical parameters to be estimated from experimental data. The optimization features are illustrated for an experimental data set involving transient water flow, solute transport

  3. Growth of single crystals of organic salts with large second-order optical nonlinearities by solution processes for devices

    NASA Technical Reports Server (NTRS)

    Leslie, Thomas M.

    1995-01-01

    Data obtained from the electric field induced second harmonic generation (EFISH) and Kurtz Powder Methods will be provided to MSFC for further refinement of their method. A theoretical model for predicting the second-order nonlinearities of organic salts is being worked on. Another task is the synthesis of a number of salts with various counterions. Several salts with promising SHG activities and new salts will be tested for the presence of two crystalline forms. The materials will be recrystallized from dry and wet solvents and compared for SHG efficiency. Salts that have a high SHG efficiency and no tendency to form hydrates will be documented. The synthesis of these materials are included in this report. A third task involves method to aid in the growth of large, high quality single crystals by solution processes. These crystals will be characterized for their applicability in the fabrication of devices that will be incorporated into optical computers in future programs. Single crystals of optimum quality may be obtained by crystal growth in low-gravity. The final task is the design of a temperature lowering single crystal growth apparatus for ground based work. At least one prototype will be built.

  4. Ion aggregation in high salt solutions. V. Graph entropy analyses of ion aggregate structure and water hydrogen bonding network

    NASA Astrophysics Data System (ADS)

    Choi, Jun-Ho; Cho, Minhaeng

    2016-05-01

    Dissolved ions in water tend to form polydisperse ion aggregates such as ion pairs, relatively compact ion clusters, and even spatially extended ion networks with increasing salt concentration. Combining molecular dynamics simulation and graph theoretical analysis methods, we recently studied morphological structures of ion aggregates with distinctively different characteristics. They can be distinguished from each other by calculating various spectral graph theoretical properties such as eigenvalues and eigenvectors of adjacency matrices of ion aggregates and water hydrogen-bonding networks, minimum path lengths, clustering coefficients, and degree distributions. Here, we focus on percolation and graph entropic properties of ion aggregates and water hydrogen-bonding networks in high salt solutions. Ion network-forming K+ and SCN- ions at high concentrations show a percolating behavior in their aqueous solutions, but ion cluster-forming ions in NaCl solutions do not show such a transition from isolated ion aggregates to percolating ion-water mixture morphology. Despite that the ion aggregate structures are strikingly different for either cluster- or network-forming ions in high salt solutions, it is interesting that the water structures remain insensitive to the electrostatic properties, such as charge densities and polydentate properties, of dissolved ions, and morphological structures of water H-bonding networks appear to be highly robust regardless of the nature and concentration of salt. We anticipate that the present graph entropy analysis results would be of use in understanding a variety of anomalous behaviors of interfacial water around biomolecules as well as electric conductivities of high electrolyte solutions.

  5. Ion aggregation in high salt solutions. V. Graph entropy analyses of ion aggregate structure and water hydrogen bonding network.

    PubMed

    Choi, Jun-Ho; Cho, Minhaeng

    2016-05-28

    Dissolved ions in water tend to form polydisperse ion aggregates such as ion pairs, relatively compact ion clusters, and even spatially extended ion networks with increasing salt concentration. Combining molecular dynamics simulation and graph theoretical analysis methods, we recently studied morphological structures of ion aggregates with distinctively different characteristics. They can be distinguished from each other by calculating various spectral graph theoretical properties such as eigenvalues and eigenvectors of adjacency matrices of ion aggregates and water hydrogen-bonding networks, minimum path lengths, clustering coefficients, and degree distributions. Here, we focus on percolation and graph entropic properties of ion aggregates and water hydrogen-bonding networks in high salt solutions. Ion network-forming K(+) and SCN(-) ions at high concentrations show a percolating behavior in their aqueous solutions, but ion cluster-forming ions in NaCl solutions do not show such a transition from isolated ion aggregates to percolating ion-water mixture morphology. Despite that the ion aggregate structures are strikingly different for either cluster- or network-forming ions in high salt solutions, it is interesting that the water structures remain insensitive to the electrostatic properties, such as charge densities and polydentate properties, of dissolved ions, and morphological structures of water H-bonding networks appear to be highly robust regardless of the nature and concentration of salt. We anticipate that the present graph entropy analysis results would be of use in understanding a variety of anomalous behaviors of interfacial water around biomolecules as well as electric conductivities of high electrolyte solutions. PMID:27250298

  6. Development of tropine-salt aqueous two-phase systems and removal of hydrophilic ionic liquids from aqueous solution.

    PubMed

    Wu, Haoran; Yao, Shun; Qian, Guofei; Song, Hang

    2016-08-26

    A novel aqueous two-phase systems (ATPS) composed of a small molecule organic compound tropine and an organic or inorganic salt aqueous solution has been developed for the first time. The phase behavior of tropine-salt ATPS was systemically investigated and the phase equilibrium data were measured in different temperatures and concentrations and correlated by the Merchuk equation with satisfactory results. The detection of the conductivity and particle size proved the formation of micelle in the process of forming tropine-salt ATPS. The separation application of the ATPS was assessed with the removal of hydrophilic benzothiazolium-based ionic liquids (ILs) from aqueous solution. The result showed that ILs were effectively extracted into the top tropine-rich phase. Finally, ILs in the top tropine-rich phase were further separated by the means of adsorption-desorption with DM301 macroporous resin and ethanol. The method of novel tropine-salt ATPS combined with adsorption-desorption is demonstrated a promising alternative thought and approach for the removal or recovery of hydrophilic compounds from aqueous media and also could provide a potential application for bio-separation. PMID:27485150

  7. A novel method of non-violent dissolution of sodium metal in a concentrated aqueous solution of Epsom salt

    NASA Astrophysics Data System (ADS)

    Lakshmanan, A. R.; Prasad, M. V. R.; Ponraju, D.; Krishnan, H.

    2004-10-01

    A new technique of non-violent and fast dissolution of sodium metal in a concentrated aqueous solution of Epsom salt (MgSO4.7H2O) at room temperature (RT) has been developed. The dissolution process is mildly exothermic but could be carried out even in a glass beaker in air under swift stirring condition. The reaction products consist of mixed salts of MgSO4 and Na2SO4 as well as Mg(OH)2 which are only mildly alkaline and hence are non-corrosive and non-hazardous unlike NaOH. A 50 mL solution having Epsom salt concentration of 2 M was found to give the optimal composition for disposal of 1 g of sodium. Supersaturated (>2.7 M), as well as dilute (<1.1 M) solutions, however, cause violent reactions and hence should be avoided. Repeated sodium dissolution in Epsom solution produced a solid waste of 4.7 g per g of sodium dissolved which is comparable with the waste (4 g) produced in 8 M NaOH solution. A 1.4 M Epsom solution sprayed with a high-pressure jet cleaner at RT in air easily removed the sodium blocked inside a metal pipe made of mild steel. The above jet also dissolved peacefully residual sodium collected on the metal tray after a sodium fire experiment. No sodium fire or explosion was observed during this campaign. The Epsom solution spray effectively neutralized the minor quantity of sodium aerosol produced during this campaign. This novel technique would hence be quite useful for draining sodium from fast breeder reactor components and bulk processing of sodium as well as for sodium fire fighting.

  8. Noble Gas (Argon and Xenon)-Saturated Cold Storage Solutions Reduce Ischemia-Reperfusion Injury in a Rat Model of Renal Transplantation

    PubMed Central

    Irani, Y.; Pype, J.L.; Martin, A.R.; Chong, C.F.; Daniel, L.; Gaudart, J.; Ibrahim, Z.; Magalon, G.; Lemaire, M.; Hardwigsen, J.

    2011-01-01

    Background Following kidney transplantation, ischemia-reperfusion injury contributes to adverse outcomes. The purpose of this study was to determine whether a cold-storage solution saturated with noble gas (xenon or argon) could limit ischemia-reperfusion injury following cold ischemia. Methods Sixty Wistar rats were randomly allocated to 4 experimental groups. Kidneys were harvested and then stored for 6 h before transplantation in cold-storage solution (Celsior®) saturated with either air, nitrogen, xenon or argon. A syngenic orthotopic transplantation was performed. Renal function was determined on days 7 and 14 after transplantation. Transplanted kidneys were removed on day 14 for histological and immunohistochemical analyses. Results Creatinine clearance was significantly higher and urinary albumin significantly lower in the argon and xenon groups than in the other groups at days 7 and 14. These effects were considerably more pronounced for argon than for xenon. In addition, kidneys stored with argon, and to a lesser extent those stored with xenon, displayed preserved renal architecture as well as higher CD-10 and little active caspase-3 expression compared to other groups. Conclusion Argon- or xenon-satured cold-storage solution preserved renal architecture and function following transplantation by reducing ischemia-reperfusion injury. PMID:22470401

  9. Probing the electron-accepting reactivity of isomeric bis(pyrrolidinium) fullerene salts in aqueous solutions

    SciTech Connect

    Guldi, D.M.

    2000-02-24

    A series of water-soluble isomer bis(pyrrolidinium) salts, with C{sub 60}(C{sub 4}H{sub 10}N{sup +}){sub 2} as cationic moiety (2a--2d), were probed in radical- and light-induced reduction studies and compared to bis(carboxylates) C{sub 60}[C(COO{sup {minus}}){sub 2}]{sub 2} and to {gamma}-CD-encapsulated C{sub 60}. Pulse radiolytic reduction of 2a--2d with hydrated electrons and (CH{sub 3}){sub 2}{sup {sm{underscore}bullet}}COH radicals leads to the formation of the fullerene {pi}-radical anion, exhibiting fingerprint absorption characteristics in the near-IR region. Because of the electron-withdrawing nature of the pyrrolidinium groups the electron-acceptor properties of the investigated bis(pyrrolidinium) salts are markedly improved relative to the bis(carboxylates) (C{sub 60}[C(COO{sup {minus}}){sub 2}]{sub 2}) and also relative to C{sub 60}. For example, the rate constants for the fullerene reduction of 2a--2d with hydrated electrons ((0.88--2.2) x 10{sup 10} M{sup {minus}1} s{sup {minus}1}) and (CH{sub 3}){sub 2}{sm{underscore}bullet}COH radicals ((4.7--7.1) x 10{sup 8} M{sup {minus}1} s{sup {minus}1}) are clearly faster than those noted for C{sub 60}[C(COO{sup {minus}}){sub 2}]{sub 2} (e{sub aq}{sup {minus}}: (0.19--0.34) x 10{sup 10} M{sup {minus}1} s{sup {minus}1}; (CH{sub 3}){sub 2}{sup {sm{underscore}bullet}}COH: (0.9--2.2) x 10{sup 8}M{sup {minus}1} s{sup {minus}1}), and C{sub 60} (e{sub aq}{sup {minus}}: 1.8 x 10{sup 10} M{sup {minus}1} s{sup {minus}1}; (CH{sub 3}){sub 2}{sup {sm{underscore}bullet}}COH: 2.7 x 10{sup 8} M{sup {minus}1} s{sup {minus}1}). Photolysis of 2a--2d gives rise to singlet excited state absorptions that closely resemble earlier observations for the pyrrolidine precursor, e.g., C{sub 60}(C{sub 3}H{sub 7}N){sub 2} (1a--1d) in deoxygenated toluene solutions. The triplet lifetimes of 2a--2d, as measured by nanosecond-resolved photolysis, are typically around 33 {mu}s, similar to the triplet lifetimes of truly monomeric fullerene

  10. Electrochemical activation of carbon cloth in aqueous inorganic salt solution for superior capacitive performance

    NASA Astrophysics Data System (ADS)

    Ye, Dong; Yu, Yao; Tang, Jie; Liu, Lin; Wu, Yue

    2016-05-01

    Carbon cloth (CC) is an inexpensive and highly conductive textile with excellent mechanical flexibility and strength; it holds great promise as an electrode material for flexible supercapacitors. However, pristine CC has such a low surface area and poor electrochemical activity that the energy storage capability is usually very poor. Herein, we report a green method, two-step electrochemical activation in an aqueous solution of inorganic salts, to significantly enhance the capacitance of CC for supercapacitor application. Micro-cracks, exfoliated carbon fiber shells, and oxygen-containing functional groups (OFGs) were introduced onto the surface of the carbon filament. This resulted in an enhancement of over two orders of magnitude in capacitance compared to that of the bare CC electrode, reaching up to a maximum areal capacitance of 505.5 mF cm-2 at the current density of 6 mA cm-2 in aqueous H2SO4 electrolyte. Electrochemical reduction of CC electrodes led to the removal of most electrochemically unstable surface OFGs, resulting in superior charging/discharging rate capability and excellent cycling stability. Although the activated CC electrode contained a high-level of surface oxygen functional groups (~15 at%), it still exhibited a remarkable charging-discharging rate capability, retaining ~88% of the capacitance when the charging rate increased from 6 to 48 mA cm-2. Moreover, the activated CC electrode exhibited excellent cycling stability with ~97% capacitance remaining after 10 000 cycles at a current density of 24 mA cm-2. A symmetrical supercapacitor based on the activated CC exhibited an ideal capacitive behavior and fast charge-discharge properties. Such a simple, environment-friendly, and cost-effective strategy to activate CC shows great potential in the fabrication of high-performance flexible supercapacitors.Carbon cloth (CC) is an inexpensive and highly conductive textile with excellent mechanical flexibility and strength; it holds great promise as