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Sample records for solide-liquide application aux

  1. Atomistic simulation of solid-liquid coexistence for molecular systems: Application to triazole and benzene

    NASA Astrophysics Data System (ADS)

    Eike, David M.; Maginn, Edward J.

    2006-04-01

    A method recently developed to rigorously determine solid-liquid equilibrium using a free-energy-based analysis has been extended to analyze multiatom molecular systems. This method is based on using a pseudosupercritical transformation path to reversibly transform between solid and liquid phases. Integration along this path yields the free energy difference at a single state point, which can then be used to determine the free energy difference as a function of temperature and therefore locate the coexistence temperature at a fixed pressure. The primary extension reported here is the introduction of an external potential field capable of inducing center of mass order along with secondary orientational order for molecules. The method is used to calculate the melting point of 1-H-1,2,4-triazole and benzene. Despite the fact that the triazole model gives accurate bulk densities for the liquid and crystal phases, it is found to do a poor job of reproducing the experimental crystal structure and heat of fusion. Consequently, it yields a melting point that is 100K lower than the experimental value. On the other hand, the benzene model has been parametrized extensively to match a wide range of properties and yields a melting point that is only 20K lower than the experimental value. Previous work in which a simple "direct heating" method was used actually found that the melting point of the benzene model was 50K higher than the experimental value. This demonstrates the importance of using proper free energy methods to compute phase behavior. It also shows that the melting point is a very sensitive measure of force field quality that should be considered in parametrization efforts. The method described here provides a relatively simple approach for computing melting points of molecular systems.

  2. Les ADAF : Application aux binaires X

    NASA Astrophysics Data System (ADS)

    Olive, Jean-Francois

    2001-01-01

    Based on the fundamental review by Narayan et al. (1998), this lecture for the ``23ieme Ecole du CNRS de Goutelas'' on binary systems describes the properties of advection-dominated accretion flows (ADAFs) and their applications to black hole X-ray binaries. The possibility of using ADAFs to explore the event horizons of black holes is highlighted.

  3. Application de la combustion catalytique aux turbines à gaz

    NASA Astrophysics Data System (ADS)

    Lebas, E.; Martin, G. H.

    2002-04-01

    La réduction des émissions d'oxydes d'azote sur turbines à gaz est obtenue par diminution de la température au sein de la chambre de combustion. Les techniques possibles comprennent l'injection d'eau ou de vapeur, la combustion pauvre et l'oxydation catalytique. Parmi celles-ci, la dernière est la plus prometteuse en terme de coûts et de performances, avec des émissions de NOx ramenées à un seul chiffre (typiquement inférieures à 3 ppm). L'IFP travaille depuis maintenant 10 ans sur l'adaptation de la combustion catalytique aux turbines à gaz. Les études ont été conduites au travers de projets européen tels que AGATA (Advance Gas Turbine for Automotive Application) et ULECAT (Ultra Low CATalytic combustor for dual fuel gas turbine). Le premier projet était destiné au développement de véhicules hybrides et le second à la combustion stationnaire de biogaz et de combustible Diesel. Les études en cours dans ce domaine portent sur le développement d'une unité de cogénération intégrant une microturbine à combustion catalytique. Les travaux menés à l'IFP concernent la mise au point de catalyseurs répondant aux exigences de la combustion catalytique en turbine à gaz et le développement de chambres de combustion permettant la mise en oeuvre de ces catalyseurs.

  4. CRYOCHEM, Thermodynamic Model for Cryogenic Chemical Systems: Solid-Vapor and Solid-Liquid-Vapor Phase Equilibria Toward Applications on Titan and Pluto

    NASA Astrophysics Data System (ADS)

    Tan, S. P.; Kargel, J. S.; Adidharma, H.; Marion, G. M.

    2014-12-01

    Until in-situ measurements can be made regularly on extraterrestrial bodies, thermodynamic models are the only tools to investigate the properties and behavior of chemical systems on those bodies. The resulting findings are often critical in describing physicochemical processes in the atmosphere, surface, and subsurface in planetary geochemistry and climate studies. The extremely cold conditions on Triton, Pluto and other Kuiper Belt Objects, and Titan introduce huge non-ideality that prevents conventional models from performing adequately. At such conditions, atmospheres as a whole—not components individually—are subject to phase equilibria with their equilibrium solid phases or liquid phases or both. A molecular-based thermodynamic model for cryogenic chemical systems, referred to as CRYOCHEM, the development of which is still in progress, was shown to reproduce the vertical composition profile of Titan's atmospheric methane measured by the Huygens probe (Tan et al., Icarus 2013, 222, 53). Recently, the model was also used to describe Titan's global circulation where the calculated composition of liquid in Ligeia Mare is consistent with the bathymetry and microwave absorption analysis of T91 Cassini fly-by data (Tan et al., 2014, submitted). Its capability to deal with equilibria involving solid phases has also been demonstrated (Tan et al., Fluid Phase Equilib. 2013, 360, 320). With all those previous works done, our attention is now shifting to the lower temperatures in Titan's tropopause and on Pluto's surface, where much technical development remains for CRYOCHEM to assure adequate performance at low temperatures. In these conditions, solid-vapor equilibrium (SVE) is the dominant phase behavior that determines the composition of the atmosphere and the existing ices. Another potential application is for the subsurface phase equilibrium, which also involves liquid, thus three-phase equilibrium: solid-liquid-vapor (SLV). This presentation will discuss the

  5. Development of an unresolved CFD-DEM model for the flow of viscous suspensions and its application to solid-liquid mixing

    NASA Astrophysics Data System (ADS)

    Blais, Bruno; Lassaigne, Manon; Goniva, Christoph; Fradette, Louis; Bertrand, François

    2016-08-01

    Although viscous solid-liquid mixing plays a key role in the industry, the vast majority of the literature on the mixing of suspensions is centered around the turbulent regime of operation. However, the laminar and transitional regimes face considerable challenges. In particular, it is important to know the minimum impeller speed (Njs) that guarantees the suspension of all particles. In addition, local information on the flow patterns is necessary to evaluate the quality of mixing and identify the presence of dead zones. Multiphase computational fluid dynamics (CFD) is a powerful tool that can be used to gain insight into local and macroscopic properties of mixing processes. Among the variety of numerical models available in the literature, which are reviewed in this work, unresolved CFD-DEM, which combines CFD for the fluid phase with the discrete element method (DEM) for the solid particles, is an interesting approach due to its accurate prediction of the granular dynamics and its capability to simulate large amounts of particles. In this work, the unresolved CFD-DEM method is extended to viscous solid-liquid flows. Different solid-liquid momentum coupling strategies, along with their stability criteria, are investigated and their accuracies are compared. Furthermore, it is shown that an additional sub-grid viscosity model is necessary to ensure the correct rheology of the suspensions. The proposed model is used to study solid-liquid mixing in a stirred tank equipped with a pitched blade turbine. It is validated qualitatively by comparing the particle distribution against experimental observations, and quantitatively by compairing the fraction of suspended solids with results obtained via the pressure gauge technique.

  6. Ti1-xAux Alloys: Hard Biocompatible Metals and Their Possible Applications

    NASA Astrophysics Data System (ADS)

    Svanidze, Eteri; Besara, Tiglet; Ozaydin, M. Fevzi; Xin, Yan; Han, Ke; Liang, Hong; Siegrist, Theo; Morosan, Emilia

    2015-03-01

    The search for new hard materials is often challenging from both theoretical and experimental points of view. Furthermore, using materials for biomedical applications calls for alloys with high biocompatibility which are even more sparse. The Ti1-xAux (0 . 22 <= x <= 0 . 8) exhibit extreme hardness and strength values, elevated melting temperatures (compared to those of constituent elements), reduced density compared to Au, high malleability, bulk metallicity, high biocompatibility, low wear, reduced friction, potentially high radio opacity, as well as osseointegration. All these properties render the Ti1-xAux alloys particularly useful for orthopedic, dental, and prosthetic applications, where they could be used as both permanent and temporary components. Additionally, the ability of Ti1-xAux alloys to adhere to ceramic parts could reduce the weight and cost of these components. The work at Rice was supported by NSF DMR 0847681 (E.M. and E.S.).

  7. Calculation of multicomponent chemical equilibria in gas-solid- liquid systems: calculation methods, thermochemical data, and applications to studies of high-temperature volcanic gases with examples from Mount St. Helens

    USGS Publications Warehouse

    Symonds, R.B.; Reed, M.H.

    1993-01-01

    This paper documents the numerical formulations, thermochemical data base, and possible applications of computer programs, SOLVGAS and GASWORKS, for calculating multicomponent chemical equilibria in gas-solid-liquid systems. SOLVGAS and GASWORKS compute simultaneous equilibria by solving simultaneously a set of mass balance and mass action equations written for all gas species and for all gas-solid or gas-liquid equilibria. Examples of gas-evaporation-from-magma and precipitation-with-cooling calculations for volcanic gases collected from Mount St. Helens are shown. -from Authors

  8. Systems and methods for monitoring a solid-liquid interface

    DOEpatents

    Stoddard, Nathan G; Lewis, Monte A.; Clark, Roger F

    2013-06-11

    Systems and methods are provided for monitoring a solid-liquid interface during a casting process. The systems and methods enable determination of the location of a solid-liquid interface during the casting process.

  9. Photoinduced crystal-to-liquid phase transitions of azobenzene derivatives and their application in photolithography processes through a solid-liquid patterning.

    PubMed

    Norikane, Yasuo; Uchida, Emi; Tanaka, Satoko; Fujiwara, Kyoko; Koyama, Emiko; Azumi, Reiko; Akiyama, Haruhisa; Kihara, Hideyuki; Yoshida, Masaru

    2014-10-01

    The direct and reversible transformation of matter between the solid and liquid phases by light at constant temperature is of great interest because of its potential applications in various manufacturing settings. We report a simple molecular design strategy for the phase transitions: azobenzenes having para-dialkoxy groups with a methyl group at the meta-position. The photolithography processes were demonstrated using the azobenzene as a photoresist in a single process combining development and etching of a copper substrate. PMID:25216186

  10. A sessile drop setup for the time-resolved synchrotron study of solid-liquid interactions: Application to intermetallic formation in 55%Al-Zn alloys

    SciTech Connect

    Bernier, N. De Bruyn, D.; De Craene, M.; Scheers, J.; Claessens, S.; Vaughan, G. B. M.; Vitoux, H.; Gleyzolle, H.; Gorges, B.

    2014-04-28

    We introduce a dedicated setup for measuring by synchrotron diffraction in-situ crystallographic and chemical information at the solid–liquid interface. This setup mostly consists of a double-heating furnace composed of a resistive heating for the solid surface and an inductive heating to produce a liquid droplet. The available high energy and high flux beams allow the rapid reaction kinetics to be investigated with very good time resolution down to 1 ms. An application of this setup is illustrated for the growth mechanisms of intermetallic phases during the hot-dipping of steel in a 55%Al-Zn bath. Results show that the three η-Al{sub 5}Fe{sub 2}, θ-Al{sub 13}Fe{sub 4}, and α-Al{sub 8}Fe{sub 2}Si phases grow at different times and rates during the dipping process, whereas the face-centered cubic AlFe{sub 3} phase is not formed.

  11. Ginzburg-Landau theory for the solid-liquid interface of bcc elements. II - Application to the classical one-component plasma, the Wigner crystal, and He-4

    NASA Technical Reports Server (NTRS)

    Zeng, X. C.; Stroud, D.

    1989-01-01

    The previously developed Ginzburg-Landau theory for calculating the crystal-melt interfacial tension of bcc elements to treat the classical one-component plasma (OCP), the charged fermion system, and the Bose crystal. For the OCP, a direct application of the theory of Shih et al. (1987) yields for the surface tension 0.0012(Z-squared e-squared/a-cubed), where Ze is the ionic charge and a is the radius of the ionic sphere. Bose crystal-melt interface is treated by a quantum extension of the classical density-functional theory, using the Feynman formalism to estimate the relevant correlation functions. The theory is applied to the metastable He-4 solid-superfluid interface at T = 0, with a resulting surface tension of 0.085 erg/sq cm, in reasonable agreement with the value extrapolated from the measured surface tension of the bcc solid in the range 1.46-1.76 K. These results suggest that the density-functional approach is a satisfactory mean-field theory for estimating the equilibrium properties of liquid-solid interfaces, given knowledge of the uniform phases.

  12. Calculation of multicomponent chemical equilibria in gas-solid-liquid systems: Calculation methods, thermochemical data, and applications to studies of high-temperature volcanic gases with examples from Mt. St. Helens

    SciTech Connect

    Symonds, R.B. ); Reed, M.H. )

    1993-10-01

    This paper documents the numerical formulations, thermochemical data base, and possible applications of computer programs, SOLVGAS and GASWORKS, for calculating multicomponent chemical equilibria in gas-solid-liquid systems. SOLVGAS and GASWORKS compute simultaneous equilibria by solving simultaneously a set of mass balance and mass action equations written for all gas species and for all gas-solid or gas-liquid equilibria. The programs interface with a thermo-chemical data base, GASTHERM, which contains coefficients for retrieval of the equilibrium constants from 25[degrees] to 1200[degrees]C. The programs and data base model dynamic chemical processes in 30- to 40-component volcanic-gas systems. The authors can model gas evaporation from magma, mixing of magmatic and hydrothermal gases, precipitation of minerals during pressure and temperature decrease, mixing of volcanic gas with air, and reaction of gases with wall rock. Examples are given of the gas-evaporation-from-magma and precipitation-with-cooling calculations for volcanic gases collected from Mt. St. Helens in September 1981. The authors predict: (1) the amounts of trace elements volatilized from shallow magma, deep magma, and wall rock, and (2) the solids that precipitate from the gas upon cooling. The predictions are tested by comparing them with the measured trace-element concentrations in gases and the observed sublimate sequence. This leads to the following conclusions: (1) most of the trace elements in the Mt. St. Helens gases are volatilized from shallow magma as simple chlorides; (2) some elements (for example, Al, Ca) exist dominantly in rock aerosols, not gases, in the gas stream; (3) near-surface cooling of the gases triggers precipitation of oxides, sulfides, halides, tungstates, and native elements; and (4) equilibrium cooling of the gases to 100[degrees]C causes most trace elements, except for Hg, Sb, and Se, to precipitate from the gas. 94 refs., 30 figs., 7 tabs.

  13. Ultrasonic characterization of solid liquid suspensions

    DOEpatents

    Panetta, Paul D.

    2010-06-22

    Using an ultrasonic field, properties of a solid liquid suspension such as through-transmission attenuation, backscattering, and diffuse field are measured. These properties are converted to quantities indicating the strength of different loss mechanisms (such as absorption, single scattering and multiple scattering) among particles in the suspension. Such separation of the loss mechanisms can allow for direct comparison of the attenuating effects of the mechanisms. These comparisons can also indicate a model most likely to accurately characterize the suspension and can aid in determination of properties such as particle size, concentration, and density of the suspension.

  14. Solid-liquid phase transition in argon

    NASA Technical Reports Server (NTRS)

    Tsang, T.; Tang, H. T.

    1978-01-01

    Starting from the Lennard-Jones interatomic potential, a modified cell theory has been used to describe the solid-liquid phase transition in argon. The cell-size variations may be evaluated by a self-consistent condition. With the inclusion of cell-size variations, the transition temperature, the solid and liquid densities, and the liquid-phase radial-distribution functions have been calculated. These ab initio results are in satisfactory agreement with molecular-dynamics calculations as well as experimental data on argon.

  15. Precise AuxPt1-x Alloy Nanoparticle Array of Tunable Composition for Catalytic Applications

    NASA Astrophysics Data System (ADS)

    Jahn, Sarah; Lechner, Sebastian J.; Freichels, Helene; Möller, Martin; Spatz, Joachim P.

    2016-02-01

    A 3-dimensional Block Copolymer Micellar nanoLithography (BCML) process was used to prepare AuxPt1-x alloy nanoparticles (NPs) monodisperse in size and composition, strongly anchored onto SiO2-particles (0.2 wt.% AuxPt1-x/SiO2). The particles possess a face-centered cubic (fcc) crystal structure and their size could be varied from 3-12 nm. We demonstrate the uniformity of the Au/Pt composition by analyzing individual NPs by energy-dispersive X-ray spectroscopy. The strongly bound AuxPt1-x NPs catalyzed the oxidation of CO with high activity. Thermal ageing experiments in pure CO2 as well as in ambient atmosphere demonstrated stability of the size distribution for times as long as 22 h.

  16. Redistribution of fluorescent molecules at the solid/liquid interface with total internal reflection illumination.

    PubMed

    Wei, Lin; Ye, Zhongju; Luo, Wenjuan; Chen, Bo; Xiao, Lehui

    2016-08-01

    Many intriguing physical and chemical processes commonly take place at the solid/liquid interface. Total internal reflection illumination, together with single molecule spectroscopy, provides a robust platform for the selective exploration of kinetic processes close the interface. With these techniques, it was observed that the distribution of Rhodamine B molecules close to a solid/liquid interface could be regulated in a photo-induced route. The laser-induced repulsion force at this interface is enough to compromise the Brownian diffusion of single molecules in a range of several hundred nanometers normal to the solid/liquid interface. This observation is fundamentally and practically interesting because moderate laser intensity is enough to initiate this repulsion effect. Therefore, it might display extensive applications in the development of photo-modulation technique with high throughput capability. PMID:27216678

  17. Coarsening in binary solid-liquid mixtures

    NASA Technical Reports Server (NTRS)

    Voorhees, P. W.

    1990-01-01

    A theory of Ostwald ripening has been developed for a solid-liquid mixture cosisting of a low volume fraction array of spherical solid particles in a liquid wherein the coarsening process proceeds via the transport of both heat and mass. It is found that the simultaneous transport of heat and mass during ripening does not alter the exponents of the temporal power laws governing the ripening process from their classical values but does alter the amplitudes of these power laws. The growth rate of the cube of the average particle radius, the rate constant, is found to depend both on the alloy solute concentration and the ratio of the thermal to solutal diffusivities. In most metallic systems, a large decrease in the rate constant can be expected with small additions of solute to a pure metal. Possible extensions of this theory to the analogous problem of ripening in isothermal ternary alloys are also discussed.

  18. An immersed boundary-thermal lattice Boltzmann method for solid-liquid phase change

    NASA Astrophysics Data System (ADS)

    Huang, Rongzong; Wu, Huiying

    2014-11-01

    In this work, an immersed boundary-thermal lattice Boltzmann method (IB-TLBM) is proposed to simulate solid-liquid phase change problems. To treat the velocity and temperature boundary conditions on the solid-liquid interface, immersed boundary method (IBM) is adopted, in which the solid-liquid interface is represented as a sharp interface rather than a diffusive interface and is tracked explicitly by Lagrangian grid. The surface forces along the immersed boundary, including the “momentum force” for velocity boundary condition and the “energy force” for temperature boundary condition, are calculated by the direct-forcing scheme. The moving velocity of solid-liquid interface induced by phase change is calculated by the amount of latent heat absorbed or released in a time step directly, with no need to compute temperature gradients in solid and liquid phases separately. The temperature on the solid-liquid interface is specified as the melting temperature, which means phase change happens at a constant temperature. As the solid-liquid interface evolves with time, the identification of phase of Eulerian points and the rearrangement of Lagrangian points are also considered. With regard to the velocity and temperature fields, passive scalar thermal lattice Boltzmann method (TLBM) with multiple-relaxation-time (MRT) collision schemes is adopted. Numerical examples, including conduction-induced melting in a semi-infinite space and melting in a square cavity, are carried out to verify the present method and good results are obtained. As a further application, melting in a circular cylinder with considering the motion of solid phase is simulated successfully by the present method; numerical results show that the motion of solid phase accelerates the melting process obviously.

  19. Computational Investigations of Solid-Liquid Interfaces

    SciTech Connect

    Mark Asta

    2011-08-31

    In a variety of materials synthesis and processing contexts, atomistic processes at heterophase interfaces play a critical role governing defect formation, growth morphologies, and microstructure evolution. Accurate knowledge of interfacial structure, free energies, mobilities and segregation coefficients are critical for predictive modeling of microstructure evolution, yet direct experimental measurement of these fundamental interfacial properties remains elusive in many cases. In this project first-principles calculations were combined with molecular-dynamics (MD) and Monte-Carlo (MC) simulations, to investigate the atomic-scale structural and dynamical properties of heterophase interfaces, and the relationship between these properties and the calculated thermodynamic and kinetic parameters that influence the evolution of phase transformation structures at nanometer to micron length scales. The topics investigated in this project were motivated primarily by phenomena associated with solidification processing of metals and alloys, and the main focus of the work was thus on solid-liquid interfaces and high-temperature grain boundaries. Additional efforts involved first-principles calculations of coherent solid-solid heterophase interfaces, where a close collaboration with researchers at the National Center for Electron Microscopy was undertaken to understand the evolution of novel core-shell precipitate microstructures in aluminum alloys.

  20. An improved technique for modeling initial reservoir hydrocarbon saturation distributions: Applications in Illinois (USA) aux vases oil reservoirs

    USGS Publications Warehouse

    Udegbunam, E.; Amaefule, J.O.

    1998-01-01

    An improved technique for modeling the initial reservoir hydrocarbon saturation distributions is presented. In contrast to the Leverett J-function approach, this methodology (hereby termed flow-unit-derived initial oil saturation or FUSOI) determines the distributions of the initial oil saturations from a measure of the mean hydraulic radius, referred to as the flow zone indicator (FZI). FZI is derived from porosity and permeability data. In the FUSOI approach, capillary pressure parameters, S(wir), P(d), and ??, derived from the Brooks and Corey (1966) model [Brooks, R.H., Corey, A.T., 1966. Hydraulic properties of porous media, Hydrology Papers, Colorado State Univ., Ft. Collins, No. 3, March.], are correlated to the FZI. Subsequent applications of these parameters then permit the computation of improved hydrocarbon saturations as functions of FZI and height above the free water level (FWL). This technique has been successfully applied in the Mississippian Aux Vases Sandstone reservoirs of the Illinois Basin (USA). The Aux Vases Zeigler field (Franklin County, IL, USA) was selected for a field-wide validation of this FUSOI approach because of the availability of published studies. With the initial oil saturations determined on a depth-by-depth basis in cored wells, it was possible to geostatistically determine the three-dimensional (3-D) distributions of initial oil saturations in the Zeigler field. The original oil-in-place (OOIP), computed from the detailed initialization of the 3-D reservoir simulation model of the Zeigler field, was found to be within 5.6% of the result from a rigorous material balance method.An improved technique for modeling the initial reservoir hydrocarbon saturation distributions is presented. In contrast to the Leverett J-function approach, this methodology (hereby termed flow-unit-derived initial oil saturation or FUSOI) determines the distributions of the initial oil saturations from a measure of the mean hydraulic radius, referred to

  1. Quantitative modeling of the equilibration of two-phase solid-liquid Fe by atomistic simulations on diffusive time scales

    NASA Astrophysics Data System (ADS)

    Asadi, Ebrahim; Asle Zaeem, Mohsen; Nouranian, Sasan; Baskes, Michael I.

    2015-01-01

    In this paper, molecular dynamics (MD) simulations based on the modified-embedded atom method (MEAM) and a phase-field crystal (PFC) model are utilized to quantitatively investigate the solid-liquid properties of Fe. A set of second nearest-neighbor MEAM parameters for high-temperature applications are developed for Fe, and the solid-liquid coexisting approach is utilized in MD simulations to accurately calculate the melting point, expansion in melting, latent heat, and solid-liquid interface free energy, and surface anisotropy. The required input properties to determine the PFC model parameters, such as liquid structure factor and fluctuations of atoms in the solid, are also calculated from MD simulations. The PFC parameters are calculated utilizing an iterative procedure from the inputs of MD simulations. The solid-liquid interface free energy and surface anisotropy are calculated using the PFC simulations. Very good agreement is observed between the results of our calculations from MEAM-MD and PFC simulations and the available modeling and experimental results in the literature. As an application of the developed model, the grain boundary free energy of Fe is calculated using the PFC model and the results are compared against experiments.

  2. Solid-liquid critical behavior of water in nanopores.

    PubMed

    Mochizuki, Kenji; Koga, Kenichiro

    2015-07-01

    Nanoconfined liquid water can transform into low-dimensional ices whose crystalline structures are dissimilar to any bulk ices and whose melting point may significantly rise with reducing the pore size, as revealed by computer simulation and confirmed by experiment. One of the intriguing, and as yet unresolved, questions concerns the observation that the liquid water may transform into a low-dimensional ice either via a first-order phase change or without any discontinuity in thermodynamic and dynamic properties, which suggests the existence of solid-liquid critical points in this class of nanoconfined systems. Here we explore the phase behavior of a model of water in carbon nanotubes in the temperature-pressure-diameter space by molecular dynamics simulation and provide unambiguous evidence to support solid-liquid critical phenomena of nanoconfined water. Solid-liquid first-order phase boundaries are determined by tracing spontaneous phase separation at various temperatures. All of the boundaries eventually cease to exist at the critical points and there appear loci of response function maxima, or the Widom lines, extending to the supercritical region. The finite-size scaling analysis of the density distribution supports the presence of both first-order and continuous phase changes between solid and liquid. At around the Widom line, there are microscopic domains of two phases, and continuous solid-liquid phase changes occur in such a way that the domains of one phase grow and those of the other evanesce as the thermodynamic state departs from the Widom line. PMID:26100904

  3. Self-instability of finite sized solid-liquid interfaces

    PubMed Central

    Wu, L.K.; Xu, B.; Li, Q.L.; Liu, W.

    2015-01-01

    In solid-liquid systems, macroscopic solids lose their equilibrium and melt in a manner that results in overall movement of the solid-liquid interface. This phenomenon occurs when they are subjected to temperature gradients or external stress, for example. However, many experiments suggest that the melting of nano- and micro-sized metallic nuclei follows a different process not described by traditional melting theory. In this paper, we demonstrate through simulation that the melting of solid nuclei of these sizes occurs via random breaches at the interfaces. Moreover, this breaching process occurs at the exact solid-liquid equilibrium temperature and in the absence of any external disturbance, which suggests the name “self-instability” for this melting process. We attribute this spontaneous instability to the curvature of the samples; based on the relationship between the sample’s instability and its curvature, we propose a destabilizing model for small systems. This model fits well with experimental results and leads to new insights into the instability behavior of small-sized systems; these insights have broad implications for research topics ranging from dendrite self-fragmentation to nanoparticle instability. PMID:26685800

  4. Precise AuxPt1−x Alloy Nanoparticle Array of Tunable Composition for Catalytic Applications

    PubMed Central

    Jahn, Sarah; Lechner, Sebastian J.; Freichels, Helene; Möller, Martin; Spatz, Joachim P.

    2016-01-01

    A 3-dimensional Block Copolymer Micellar nanoLithography (BCML) process was used to prepare AuxPt1−x alloy nanoparticles (NPs) monodisperse in size and composition, strongly anchored onto SiO2-particles (0.2 wt.% AuxPt1−x/SiO2). The particles possess a face-centered cubic (fcc) crystal structure and their size could be varied from 3–12 nm. We demonstrate the uniformity of the Au/Pt composition by analyzing individual NPs by energy-dispersive X-ray spectroscopy. The strongly bound AuxPt1−x NPs catalyzed the oxidation of CO with high activity. Thermal ageing experiments in pure CO2 as well as in ambient atmosphere demonstrated stability of the size distribution for times as long as 22 h. PMID:26856888

  5. Methods and systems for monitoring a solid-liquid interface

    SciTech Connect

    Stoddard, Nathan G.; Clark, Roger F.; Kary, Tim

    2010-07-20

    Methods and systems are provided for monitoring a solid-liquid interface, including providing a vessel configured to contain an at least partially melted material; detecting radiation reflected from a surface of a liquid portion of the at least partially melted material that is parallel with the liquid surface; measuring a disturbance on the surface; calculating at least one frequency associated with the disturbance; and determining a thickness of the liquid portion based on the at least one frequency, wherein the thickness is calculated based on.times. ##EQU00001## where g is the gravitational constant, w is the horizontal width of the liquid, and f is the at least one frequency.

  6. UV patterned nanoporous solid-liquid core waveguides.

    PubMed

    Gopalakrishnan, Nimi; Sagar, Kaushal S; Christiansen, Mads Brøkner; Vigild, Martin E; Ndoni, Sokol; Kristensen, Anders

    2010-06-01

    Nanoporous Solid-Liquid core waveguides were prepared by UV induced surface modification of hydrophobic nanoporous polymers. With this method, the index contrast (deltan = 0.20) is a result of selective water infiltration. The waveguide core is defined by UV light, rendering the exposed part of a nanoporous polymer block hydrophilic. A propagation loss of 0.62 dB/mm and a bend loss of 0.81 dB/90 degrees for bend radius as low as 1.75 mm was obtained in these multimode waveguides. PMID:20588419

  7. A hybrid solid-liquid polymer photodiode for the bioenvironment

    NASA Astrophysics Data System (ADS)

    Antognazza, M. R.; Ghezzi, D.; Musitelli, D.; Garbugli, M.; Lanzani, G.

    2009-06-01

    We demonstrate that a prototypical semiconducting polymer, poly[2-methoxy-5-(2'-ethylhexyloxy)-p-phenylene vinylene] (MEH-PPV) maintains unaltered its optoelectronic properties throughout the various steps for neural preparation. Films of MEH-PPV, after prolonged immersion in water or buffer solution, are characterized by linear and nonlinear optical spectroscopy. Based on this result, we introduce a hybrid solid-liquid photodiode based on MEH-PPV, in which we use culturing media as liquid, ionic cathodes. The hybrid device is proposed as an active interface between living tissue and conducting polymers for cell diagnostic and neural implants.

  8. Modelling temperature and concentration dependent solid/liquid interfacial energies

    NASA Astrophysics Data System (ADS)

    Lippmann, Stephanie; Jung, In-Ho; Paliwal, Manas; Rettenmayr, Markus

    2016-01-01

    Models for the prediction of the solid/liquid interfacial energy in pure substances and binary alloys, respectively, are reviewed and extended regarding the temperature and concentration dependence of the required thermodynamic entities. A CALPHAD-type thermodynamic database is used to introduce temperature and concentration dependent melting enthalpies and entropies for multicomponent alloys in the temperature range between liquidus and solidus. Several suitable models are extended and employed to calculate the temperature and concentration dependent interfacial energy for Al-FCC with their respective liquids and compared with experimental data.

  9. Bioinspired solid-liquid mixed tunable lens with multilayered structure

    NASA Astrophysics Data System (ADS)

    Liang, Dan; Wang, Xuan-Yin; Du, Jia-Wei

    2015-06-01

    A solid-liquid mixed tunable lens with multilayered structure is proposed. The designed lens utilizes a solid-state elastic polymer, optical liquid, and glass as the optical medium, and adjusts the focus by changing the surface curvature of the elastic polymer. The integrated structure of the tunable lens is presented, as well as detailed descriptions of the lens materials, fabrication, and assembling process. Images captured through the tunable lens under different displacement loads are presented, and the relationship among the displacement load, curvature radius, and effective focal length is analyzed. Additionally, the optical property of the tunable lens is simulated using the ZEMAX software. A change in focal length from 14.8 mm to 30 mm is demonstrated within the tiny 0.12 mm variation of the displacement load. Numerical analyses show that the lens distortion is less than 2%, and the modulation transfer function reaches 67 line pairs per mm. The solid-liquid mixed tunable lens shows the potential for developing a compact, low-aberration, and stable optical system.

  10. Solid-liquid work of adhesion of coarse-grained models of n-hexane on graphene layers derived from the conditional reversible work method

    SciTech Connect

    Ardham, Vikram Reddy; Leroy, Frédéric E-mail: f.leroy@theo.chemie.tu-darmstadt.de; Deichmann, Gregor; Vegt, Nico F. A. van der E-mail: f.leroy@theo.chemie.tu-darmstadt.de

    2015-12-28

    We address the question of how reducing the number of degrees of freedom modifies the interfacial thermodynamic properties of heterogeneous solid-liquid systems. We consider the example of n-hexane interacting with multi-layer graphene which we model both with fully atomistic and coarse-grained (CG) models. The CG models are obtained by means of the conditional reversible work (CRW) method. The interfacial thermodynamics of these models is characterized by the solid-liquid work of adhesion W{sub SL} calculated by means of the dry-surface methodology through molecular dynamics simulations. We find that the CRW potentials lead to values of W{sub SL} that are larger than the atomistic ones. Clear understanding of the relationship between the structure of n-hexane in the vicinity of the surface and W{sub SL} is elucidated through a detailed study of the energy and entropy components of W{sub SL}. We highlight the crucial role played by the solid-liquid energy fluctuations. Our approach suggests that CG potentials should be designed in such a way that they preserve the range of solid-liquid interaction energies, but also their fluctuations in order to preserve the reference atomistic value of W{sub SL}. Our study thus opens perspectives into deriving CG interaction potentials that preserve the thermodynamics of solid-liquid contacts and will find application in studies that intend to address materials driven by interfaces.

  11. Solid-liquid coexistence of polydisperse fluids via simulation.

    PubMed

    Wilding, Nigel B

    2009-03-14

    We describe a simulation method for the accurate study of the equilibrium freezing properties of polydisperse fluids under the experimentally relevant condition of fixed polydispersity. The approach is based on the phase switch Monte Carlo method of Wilding and Bruce [Phys. Rev. Lett. 85, 5138 (2000)]. This we have generalized to deal with particle size polydispersity by incorporating updates which alter the diameter sigma of a particle, under the control of a distribution of chemical potential differences mu(sigma). Within the resulting isobaric semi-grand-canonical ensemble, we detail how to adapt mu(sigma) and the applied pressure such as to study coexistence, while ensuring that the ensemble averaged density distribution rho(sigma) matches a fixed functional form. Results are presented for the effects of small degrees of polydispersity on the solid-liquid transition of soft spheres. PMID:19292519

  12. Resolving amorphous solid-liquid interfaces by atomic force microscopy

    NASA Astrophysics Data System (ADS)

    Burson, Kristen M.; Gura, Leonard; Kell, Burkhard; Büchner, Christin; Lewandowski, Adrian L.; Heyde, Markus; Freund, Hans-Joachim

    2016-05-01

    Recent advancements in liquid atomic force microscopy make it an ideal technique for probing the structure of solid-liquid interfaces. Here, we present a structural study of a two-dimensional amorphous silica bilayer immersed in an aqueous solution utilizing liquid atomic force microscopy with sub-nanometer resolution. Structures show good agreement with atomically resolved ultra-high vacuum scanning tunneling microscopy images obtained on the same sample system, owing to the structural stability of the silica bilayer and the imaging clarity from the two-dimensional sample system. Pair distance histograms of ring center positions are utilized to develop quantitative metrics for structural comparison, and the physical origin of pair distance histogram peaks is addressed by direct assessment of real space structures.

  13. Solid/liquid interfacial free energies in binary systems

    NASA Technical Reports Server (NTRS)

    Nason, D.; Tiller, W. A.

    1973-01-01

    Description of a semiquantitative technique for predicting the segregation characteristics of smooth interfaces between binary solid and liquid solutions in terms of readily available thermodynamic parameters of the bulk solutions. A lattice-liquid interfacial model and a pair-bonded regular solution model are employed in the treatment with an accommodation for liquid interfacial entropy. The method is used to calculate the interfacial segregation and the free energy of segregation for solid-liquid interfaces between binary solutions for the (111) boundary of fcc crystals. The zone of compositional transition across the interface is shown to be on the order of a few atomic layers in width, being moderately narrower for ideal solutions. The free energy of the segregated interface depends primarily upon the solid composition and the heats of fusion of the component atoms, the composition difference of the solutions, and the difference of the heats of mixing of the solutions.

  14. Methods and systems for monitoring a solid-liquid interface

    SciTech Connect

    Stoddard, Nathan G.; Clark, Roger F.

    2011-10-04

    Methods and systems are provided for monitoring a solid-liquid interface, including providing a vessel configured to contain an at least partially melted material; detecting radiation reflected from a surface of a liquid portion of the at least partially melted material; providing sound energy to the surface; measuring a disturbance on the surface; calculating at least one frequency associated with the disturbance; and determining a thickness of the liquid portion based on the at least one frequency, wherein the thickness is calculated based on L=(2m-1)v.sub.s/4f, where f is the frequency where the disturbance has an amplitude maximum, v.sub.s is the speed of sound in the material, and m is a positive integer (1, 2, 3, . . . ).

  15. Transport phenomena during solid-liquid phase change in porous media

    SciTech Connect

    Pak, J.; Plumb, O.A.

    1995-12-31

    Transport phenomena in porous media with phase change has been studied in a wide variety of both environmental and engineering systems during the past several decades. Examples of applications of interest include the freezing and melting of soils, thermal energy storage, and post accident analysis of nuclear reactors. The present study focuses on the solid-liquid phase change occurring during the melting of a packed bed. Particular attention is paid to the redistribution of mass. The results are applicable to the manufacture of powder based composites, ceramic-metal or certain metal-metal combinations. Due to the process used in producing ceramics and advanced alloys, many of the raw materials utilized in advanced composites are powders. The objective of the present study is to develop a general model for solid-liquid phase change which results from the application of heat to a porous structure. The system of interest is a packed bed which contains melting and non melting components. A one-dimensional phase change process is examined in this study. The macroscopic energy equation and continuity equations for both the liquid and solid phases are solved numerically and experiments are conducted to confirm the numerical results. The non melting particles used in the experiments are spherical glass beads. Salol (benzoic acid 2-hydroxyphenylester) is chosen as the phase change material because of its low melting temperature and available thermophysical properties. During the melting process, redistribution of the mass of salol was monitored utilizing gamma attenuation and compared with the numerical results. The effects of varying the particle diameter and the geometric melting model from constant volume to constant porosity are discussed.

  16. Mechanisms of reduced solute diffusivity at nanoconfined solid-liquid interface

    NASA Astrophysics Data System (ADS)

    Mahadevan, T.; Kojic, M.; Ferrari, M.; Ziemys, A.

    2013-06-01

    We report results from molecular simulations that reveal the causes of reduced diffusivity at solid-liquid interfaces in the presence of nanoscale confinement. The diffusion of a 2 M glucose solution was simulated inside a 10 nm silica channel together with the calculated thermodynamic properties of diffusion. A strong energy-entropy compensation mechanism was found at the interface with a free energy minimum of -0.6 kcal/mol. Using the Eyring equation the average jump length was reduced by 15% at interface. The complete loss of solute diffusivity at silica surface was explained by the substantial loss of the probability of productive displacements. The results suggested that glucose molecule diffusivity close to the surface might be related to a stiffer cage of the hydration shell, which affects the probability of cage breaking. These results help in understanding of diffusion mechanisms at interface and predicting mass transport in nanoconfinement for engineering and biomedical applications.

  17. Intermetallic Compound Formation Mechanisms for Cu-Sn Solid-Liquid Interdiffusion Bonding

    NASA Astrophysics Data System (ADS)

    Liu, H.; Wang, K.; Aasmundtveit, K. E.; Hoivik, N.

    2012-09-01

    Cu-Sn solid-liquid interdiffusion (SLID) bonding is an evolving technique for wafer-level packaging which features robust, fine pitch and high temperature tolerance. The mechanisms of Cu-Sn SLID bonding for wafer-level bonding and three-dimensional (3-D) packaging applications have been studied by analyzing the microstructure evolution of Cu-Sn intermetallic compounds (IMCs) at elevated temperature up to 400°C. The bonding time required to achieve a single IMC phase (Cu3Sn) in the final interconnects was estimated according to the parabolic growth law with consideration of defect-induced deviation. The effect of predominantly Cu metal grain size on the Cu-Sn interdiffusion rate is discussed. The temperature versus time profile (ramp rate) is critical to control the morphology of scallops in the IMC. A low temperature ramp rate before reaching the bonding temperature is believed to be favorable in a SLID wafer-level bonding process.

  18. Solid-Liquid Self-Adaptive Polymeric Composite.

    PubMed

    Dong, Pei; Chipara, Alin Cristian; Loya, Phillip; Yang, Yingchao; Ge, Liehui; Lei, Sidong; Li, Bo; Brunetto, Gustavo; Machado, Leonardo D; Hong, Liang; Wang, Qizhong; Yang, Bilan; Guo, Hua; Ringe, Emilie; Galvao, Douglas S; Vajtai, Robert; Chipara, Mircea; Tang, Ming; Lou, Jun; Ajayan, Pulickel M

    2016-01-27

    A solid-liquid self-adaptive composite (SAC) is synthesized using a simple mixing-evaporation protocol, with poly(dimethylsiloxane) (PDMS) and poly(vinylidene fluoride) (PVDF) as active constituents. SAC exists as a porous solid containing a near equivalent distribution of the solid (PVDF)-liquid (PDMS) phases, with the liquid encapsulated and stabilized within a continuous solid network percolating throughout the structure. The pores, liquid, and solid phases form a complex hierarchical structure, which offers both mechanical robustness and a significant structural adaptability under external forces. SAC exhibits attractive self-healing properties during tension, and demonstrates reversible self-stiffening properties under compression with a maximum of 7-fold increase seen in the storage modulus. In a comparison to existing self-healing and self-stiffening materials, SAC offers distinct advantages in the ease of fabrication, high achievable storage modulus, and reversibility. Such materials could provide a new class of adaptive materials system with multifunctionality, tunability, and scale-up potentials. PMID:26720058

  19. Solid-Liquid Interface Characterization Hardware: Advanced Technology Development (ATD)

    NASA Technical Reports Server (NTRS)

    Peters, Palmer N.; Sisk, R. C.; Sen, S.; Kaukler, W. F.; Curreri, Peter A.; Wang, F. C.; Rose, M. Franklin (Technical Monitor)

    2000-01-01

    This ATD has the goal of enabling the integration of three separate measurement techniques to characterize the solid-liquid interface of directionally solidified materials in real-time. Arrays of film-based metal thermocouple elements are under development along with compact Seebeck furnaces suitable for interfacing with separately developed X-ray Transmission Microscopes. Results of applying film arrays to furnace profiling are shown, demonstrating their ability to identify a previously undetected hardware flaw in the development of a second-generation compact furnace. Results of real-time furnace profiling also confirmed that the compact furnace design effectively isolates the temperature profiles in two halves of the furnace, a necessary feature. This isolation had only been inferred previously from the characteristics of Seebeck data reported. Results from a 24-thermocouple array successfully monitoring heating and isothermal cooling of a tin sample are shown. The importance of non-intrusion by the arrays, as well as furnace design, on the profiling of temperature gradients is illustrated with example measurements. Further developments underway for effectively combining all three measurements are assessed in terms of improved x-ray transmission, increased magnification, integral arrays with minimum intrusion, integral scales for velocity measurements and other features being incorporated into the third generation Seebeck furnace under construction.

  20. Probing Hydrophilic Interface of Solid/Liquid-Water by Nanoultrasonics

    PubMed Central

    Mante, Pierre-Adrien; Chen, Chien-Cheng; Wen, Yu-Chieh; Chen, Hui-Yuan; Yang, Szu-Chi; Huang, Yu-Ru; -Ju Chen, I.; Chen, Yun-Wen; Gusev, Vitalyi; Chen, Miin-Jang; Kuo, Jer-Lai; Sheu, Jinn-Kong; Sun, Chi-Kuang

    2014-01-01

    Despite the numerous devoted studies, water at solid interfaces remains puzzling. An ongoing debate concerns the nature of interfacial water at a hydrophilic surface, whether it is more solid-like, ice-like, or liquid-like. To answer this question, a complete picture of the distribution of the water molecule structure and molecular interactions has to be obtained in a non-invasive way and on an ultrafast time scale. We developed a new experimental technique that extends the classical acoustic technique to the molecular level. Using nanoacoustic waves with a femtosecond pulsewidth and an ångström resolution to noninvasively diagnose the hydration structure distribution at ambient solid/water interface, we performed a complete mapping of the viscoelastic properties and of the density in the whole interfacial water region at hydrophilic surfaces. Our results suggest that water in the interfacial region possesses mixed properties and that the different pictures obtained up to now can be unified. Moreover, we discuss the effect of the interfacial water structure on the abnormal thermal transport properties of solid/liquid interfaces. PMID:25176017

  1. Solid-liquid phase boundaries of lens protein solutions.

    PubMed Central

    Berland, C R; Thurston, G M; Kondo, M; Broide, M L; Pande, J; Ogun, O; Benedek, G B

    1992-01-01

    We report measurement of the solid-liquid phase boundary, or liquidus line, for aqueous solutions of three pure calf gamma-crystallin proteins: gamma II, gamma IIIa, and gamma IIIb. We also studied the liquidus line for solutions of native gamma IV-crystallin calf lens protein, which consists of 85% gamma IVa/15% gamma IVb. In all four proteins the liquidus phase boundaries lie higher in temperature than the previously determined liquid-liquid coexistence curves. Thus, over the range of concentration and temperature for which liquid-liquid phase separation occurs, the coexistence of a protein crystal phase with a protein liquid solution phase is thermodynamically stable relative to the metastable separated liquid phases. The location of the liquidus lines clearly divides these four crystallin proteins into two groups: those in which liquidus lines flatten at temperatures greater than 70 degrees C: gamma IIIa and gamma IV, and those in which liquidus lines flatten at temperatures less than 50 degrees C: gamma II and gamma IIIb. We have analyzed the form of the liquidus lines by using specific choices for the structures of the Gibbs free energy in solution and solid phases. By applying the thermodynamic conditions for equilibrium between the two phases to the resulting chemical potentials, we can estimate the temperature-dependent free energy change upon binding of protein and water into the solid phase. PMID:1741375

  2. Final Report: Thermal Conductance of Solid-Liquid Interfaces

    SciTech Connect

    Cahil, David, G.; Braun, Paul, V.

    2006-05-31

    Research supported by this grant has significantly advanced fundamental understanding of the thermal conductance of solid-liquid interfaces, and the thermal conductivity of nanofluids and nanoscale composite materials. • The thermal conductance of interfaces between carbon nanotubes and a surrounding matrix of organic molecules is exceptionally small and this small value of the interface conductance limits the enhancement in thermal conductivity that can be achieved by loading a fluid or a polymer with nanotubes. • The thermal conductance of interfaces between metal nanoparticles coated with hydrophilic surfactants and water is relatively high and surprisingly independent of the details of the chemical structure of the surfactant. • We extended our experimental methods to enable studies of planar interfaces between surfactant-coated metals and water where the chemical functionalization can be varied between strongly hydrophobic and strongly hydrophilic. The thermal conductance of hydrophobic interfaces establishes an upper-limit of 0.25 nm on the thickness of the vapor-layer that is often proposed to exist at hydrophobic interfaces. • Our high-precision measurements of fluid suspensions show that the thermal conductivity of fluids is not significantly enhanced by loading with a small volume fraction of spherical nanoparticles. These experimental results directly contradict some of the anomalous results in the recent literature and also rule-out proposed mechanisms for the enhanced thermal conductivity of nanofluids that are based on modification of the fluid thermal conductivity by the coupling of fluid motion and the Brownian motion of the nanoparticles.

  3. Interaction of Porosity with a Planar Solid/Liquid Interface

    NASA Technical Reports Server (NTRS)

    Catalina, Adrian V.; Stefanescu, Doru M.; Sen, Subhayu; Kaukler, William F.

    2004-01-01

    In this article, an investigation of the interaction between gas porosity and a planar solid/liquid (SL) interface is reported. A two-dimensional numerical model able to accurately track sharp SL interfaces during solidification of pure metals and alloys is proposed. The finite-difference method and a rectangular undeformed grid are used for computation. The SL interface is described through the points of intersection with the grid lines. Its motion is determined by the thermal and solute gradients at each particular point. Changes of the interface temperature because of capillarity or solute redistribution as well as any perturbation of the thermal and solute field produced by the presence of non-metallic inclusions can be computed. To validate the model, the dynamics of the interaction between a gas pore and a solidification front in metal alloys was observed using a state of the art X-ray transmission microscope (XTM). The experiments included observation of the distortion of the SL interface near a pore, real-time measurements of the growth rate, and the change in shape of the porosity during interaction with the SL interface in pure Al and Al-0.25 wt pct Au alloy. In addition, porosity-induced solute segregation patterns surrounding a pore were also quantified.

  4. Interaction of Porosity with a Planar Solid/Liquid Interface

    NASA Technical Reports Server (NTRS)

    Catalina, Adrian V.; Stefanescu, Doru M.; Sen, Subhayu; Kaukler, William K.; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    In this paper, an investigation of the interaction between gas porosity and a planar solid/liquid (SL) interface is reported. A two-dimensional numerical model able to accurately track sharp SL interfaces during solidification of pure metals and alloys is proposed. The finite difference method and a rectangular undeformed grid are used for computation. The SL interface is described through the points of intersection with the grid lines. Its motion is determined by the thermal and solute gradients at each particular point. Changes of the interface temperature because of capillarity or solute redistribution as well as any perturbation of the thermal and solute field produced by the presence of non-metallic inclusions can be computed. To validate the model, the dynamics of the interaction between a gas pore and a solidification front in metal alloys was observed using a state of the art X-ray Transmission Microscope. The experiments included observation of the distortion of the SL interface near a pore, real-time measurements of the growth rate and the change in shape of the porosity during interaction with an advancing SL interface in pure Al and Al-0.25 wt% Au alloy. In addition, porosity induced solute segregation patterns surrounding a pore were also quantified.

  5. Wastewater Triad Project: Solid-Liquid Separator FY 2000 Deployment

    SciTech Connect

    Walker, J.F.

    2001-01-11

    The Wastewater Triad Project (WTP) consists of three operational units: the cesium removal (CsR) system, the out-of-tank evaporator (OTE) system, and the solid/liquid separation (SLS) system. These systems were designed to reduce the volume and radioactivity of low-level liquid waste (LLLW) stored in the Melton Valley Storage Tanks (MVSTs) and are operated independently or in series in order to accomplish the treatment goals. Each is a modular, skid-mounted system that is self-contained, individually shielded, and designed to be decontaminated and removed once the project has been completed. The CsR and OTE systems are installed inside Building 7877; the SLS system is installed adjacent to the east side of the MVST 7830 vault cover. The CsR, which consists of ion-exchange equipment for removing {sup 137}Cs from LLLW, was demonstrated in 1997. During the Cesium Removal Demonstration, 30,853 gal of radioactive supernate was processed and 1142 Ci of {sup 137}Cs was removed from the supernate and loaded onto 70 gal of a crystalline silicotitanate sorbent manufactured by UOP, Inc. The OTE system is a subatmospheric single-stage evaporator system designed to concentrate LLLW to smaller volumes. It was previously demonstrated in 1996 and was operated in 1998 to process about 80,000 gal of LLLW. The SLS system was designed to filter and remove suspended solids from LLLW in order to minimize further accumulation of sludge in new storage tanks or to prevent fouling of CsR and OTE systems. The SLS was installed and demonstrated in 1999; {approximately}45,000 gal of radioactive supernate was processed during the demonstration.

  6. Solid/liquid lubrication of ceramics at elevated temperatures

    SciTech Connect

    Erdemir, A.; Erck, R.A.; Fenske, G.R.; Hong, H.

    1996-04-01

    This study investigates the effect of solid and liquid lubrication on friction and wear performance of silicon nitride (Si{sub 3}N{sub 4}) and cast iron. The solid lubricant was a thin silver film ({approx}2 {mu}m thick) produced on Si{sub 3}N{sub 4} by ion-beam-assisted deposition. A high-temperature polyol-ester-base synthetic oil served as the liquid lubricant. Friction and wear tests were performed with pin-on-disk and oscillating-slider wear test machines at temperatures up to 300{degrees}C. Without the silver films, the friction coefficients of Si{sub 3}N{sub 4}/Si{sub 3}N{sub 4} test pairs were 0.05 to 0.14, and the average wear rates of Si{sub 3}N{sub 4} pins were {approx}5 x 10{sup -8} mm{sup 3} N{sup -1}. The friction coefficients of Si{sub 3}N{sub 4}/cast iron test pairs ranged from 0.08 to 0.11, depending on test temperature. The average specific wear rates of cast iron pins were {approx}3 x 10{sup -7} mm{sup 3} N{sup -1} m{sup -1}. However, simultaneous use of the solid-lubricant silver and synthetic oil on the sliding surfaces reduced friction coefficients to 0.02 to 0.08. Moreover, the wear of Si{sub 3}N{sub 4} pins and silver-coated Si{sub 3}N{sub 4} disks was so low that it was difficult to assess by a surface profilometer. The wear rates of cast iron pins were {approx}7 x 10{sup -9} mm{sup 3} N{sup -1} m{sup -1} up to 250{degrees}C, but showed a tendency to increase slightly at much higher temperatures. In general, the test results demonstrated that the solid/liquid lubrication of ceramic and/or metallic components is both feasible and effective in controlling friction and wear.

  7. Coarsening in Solid Liquid Systems: A Verification of Fundamental Theory

    NASA Astrophysics Data System (ADS)

    Thompson, John D.

    Coarsening is a process that occurs in nearly all multi-phase materials in which the total energy of a system is reduced through the reduction of total interfacial energy. The theoretical description of this process is of central importance to materials design, yet remains controversial. In order to directly compare experiment to theoretical predictions, low solid volume fraction PbSn alloys were coarsened in a microgravity environment aboard the International Space Station (ISS) as part of the Coarsening in Solid Liquid Mixtures (CSLM) project. PbSn samples with solid volume fractions of 15%, 20% and 30% were characterized in 2D and 3D using mechanical serial sectioning. The systems were observed in the self-similar regime predicted by theory and the particle size and particle density obeyed the temporal power laws predicted by theory. However, the magnitudes of the rate constants governing those temporal laws as well as the forms of the particle size distributions were not described well by theoretical predictions. Additionally, in the 30% solid volume fraction system, the higher volume fraction results in a non-spherical particle shape and a more closely packed spatial distribution. The presence of slow particle motion induced by vibrations on the ISS is presented as an explanation for this discrepancy. To model the effect of this particle motion, the Akaiwa-Voorhees multiparticle diffusion simulations are modified to treat coarsening in the presence of a small convection term, such as that of sedimentation, corresponding to low Peclet numbers. The simulations indicate that the particle size dependent velocity of the sedimentation increases the rate at which the system coarsens. This is due to the larger particles traveling farther than normal, resulting in them encountering more small particles, which favors their growth. Additionally, sedimentation resulted in broader PSDs with a peak located at the average particle size. When the simulations are modified to

  8. Atomistic simulations of the solid-liquid transition of 1-ethyl-3-methyl imidazolium bromide ionic liquid.

    PubMed

    Feng, Haijun; Zhou, Jian; Qian, Yu

    2011-10-14

    Achieving melting point around room temperature is important for applications of ionic liquids. In this work, molecular dynamics simulations are carried out to investigate the solid-liquid transition of ionic liquid 1-ethyl-3-methyl imidazolium bromide ([emim]Br) by direct heating, hysteresis, void-nucleation, sandwich, and microcanonical ensemble approaches. Variations of the non-bonded energy, density, diffusion coefficient, and translational order parameter of [emim]Br are analyzed as a function of temperature, and a coexisting solid-liquid system is achieved in the microcanonical ensemble method. The melting points obtained from the first three methods are 547 ± 8 K, 429 ± 8 K, and 370 ± 6 K; while for the sandwich method, the melting points are 403 ± 4 K when merging along the x-axis by anisotropic isothermal-isobaric (NPT) ensemble, 393 ± 4 K when along the y-axis by anisotropic NPT ensemble, and 375 ± 4 K when along the y-axis by isotropic NPT ensemble. For microcanonical ensemble method, when the slabs are merging along different directions (x-axis, y-axis, and z-axis), the melting points are 364 ± 3 K, 365 ± 3 K, and 367 ± 3 K, respectively, the melting points we get by different methods are approximately 55.4%, 21.9%, 5.1%, 14.5%, 11.6%, 6.5%, 3.4%, 3.7%, and 4.3% higher than the experimental value of 352 K. The advantages and disadvantages of each method are discussed. The void-nucleation and microcanonical ensemble methods are most favorable for predicting the solid-liquid transition. PMID:22010721

  9. TOPICAL REVIEW: Sensors and actuators based on surface acoustic waves propagating along solid liquid interfaces

    NASA Astrophysics Data System (ADS)

    Lindner, Gerhard

    2008-06-01

    The propagation of surface acoustic waves (SAWs) along solid-liquid interfaces depends sensitively on the properties of the liquid covering the solid surface and may result in a momentum transfer into the liquid and thus a propulsion effect via acoustic streaming. This review gives an overview of the design of different SAW devices used for the sensing of liquids and the basic mechanisms of the interaction of SAWs with overlaying liquids. In addition, applications of devices based on these phenomena with respect to touch sensing and the measurement of liquid properties such as density, viscosity or the composition of mixed liquids are described, including microfabricated as well as macroscopic devices made from non-piezoelectric materials. With respect to the rapidly growing field of acoustic streaming applications, recent developments in the movement of nanolitre droplets on a single piezoelectric chip, the rather macroscopic approaches to the acoustic pumping of liquids in channels and recent attempts at numerical simulations of acoustic streaming are reported.

  10. Adsorption of hydrophobin/β-casein mixtures at the solid-liquid interface.

    PubMed

    Tucker, I M; Petkov, J T; Penfold, J; Thomas, R K; Cox, A R; Hedges, N

    2016-09-15

    The adsorption behaviour of mixtures of the proteins β-casein and hydrophobin at the hydrophilic solid-liquid surface have been studied by neutron reflectivity. The results of measurements from sequential adsorption and co-adsorption from solution are contrasted. The adsorption properties of protein mixtures are important for a wide range of applications. Because of competing factors the adsorption behaviour of protein mixtures at interfaces is often difficult to predict. This is particularly true for mixtures containing hydrophobin as hydrophobin possesses some unusual surface properties. At β-casein concentrations ⩾0.1wt% β-casein largely displaces a pre-adsorbed layer of hydrophobin at the interface, similar to that observed in hydrophobin-surfactant mixtures. In the composition and concentration range studied here for the co-adsorption of β-casein-hydrophobin mixtures the adsorption is dominated by the β-casein adsorption. The results provide an important insight into how the competitive adsorption in protein mixtures of hydrophobin and β-casein can impact upon the modification of solid surface properties and the potential for a wide range of colloid stabilisation applications. PMID:27288573

  11. Tunable synergism/antagonism in a mixed nonionic/anionic surfactant layer at the solid/liquid interface.

    PubMed

    Lu, Shaohua; Somasundaran, Ponisseril

    2008-04-15

    The use of mixed surfactants for modification of solid surfaces is important for many applications, since beneficial synergism often occurs depending on the surfactant type and mixing conditions. Systematical information on the properties of surfactant mixtures at the solid/liquid interface can be helpful for optimizing the interactions between the surfactants and then their corresponding performance. In this work, a nonionic/anionic surfactant combination, n-dodecyl beta-d-maltoside (DM) and sodium dodecyl sulfonate (SDS), was selected for the study of adsorption on an oxide solid, alumina. Interestingly, the mixture of the two surfactants with opposite pH-dependence of adsorption on alumina exhibits some unique synergistic or antagonistic features that were found to be tunable in the region of pH 4-10. In addition, the DM/SDS molar ratio in the adsorbed layer was found to decrease with concentration in the saturated region at all the pH and mixing ratios tested. The decrease is attributed to the monomer concentration changes in solution due to the difference in surface activities of the two surfactants. The tunable features of this mixture at the solid/liquid interface provide a way to optimize the properties by changing the mixing conditions. This can be valuable in many applications, such as enhanced oil recovery, flotation, and solubilization. PMID:18324849

  12. Modeling the solid-liquid phase transition in saturated triglycerides

    NASA Astrophysics Data System (ADS)

    Pink, David A.; Hanna, Charles B.; Sandt, Christophe; MacDonald, Adam J.; MacEachern, Ronald; Corkery, Robert; Rousseau, Dérick

    2010-02-01

    We investigated theoretically two competing published scenarios for the melting transition of the triglyceride trilaurin (TL): those of (1) Corkery et al. [Langmuir 23, 7241 (2007)], in which the average state of each TL molecule in the liquid phase is a discotic "Y" conformer whose three chains are dynamically twisted, with an average angle of ˜120° between them, and those of (2) Cebula et al. [J. Am. Oil Chem. Soc. 69, 130 (1992)], in which the liquid-state conformation of the TL molecule in the liquid phase is a nematic h∗-conformer whose three chains are in a modified "chair" conformation. We developed two competing models for the two scenarios, in which TL molecules are in a nematic compact-chair (or "h") conformation, with extended, possibly all-trans, chains at low-temperatures, and in either a Y conformation or an h∗ conformation in the liquid state at temperatures higher than the phase-transition temperature, T∗=319 K. We defined an h-Y model as a realization of the proposal of Corkery et al. [Langmuir 23, 7241 (2007)], and explored its predictions by mapping it onto an Ising model in a temperature-dependent field, performing a mean-field approximation, and calculating the transition enthalpy ΔH. We found that the most plausible realization of the h-Y model, as applied to the solid-liquid phase transition in TL, and likely to all saturated triglycerides, gave a value of ΔH in reasonable agreement with the experiment. We then defined an alternative h-h∗ model as a realization of the proposal of Cebula et al. [J. Am. Oil Chem. Soc. 69, 130 (1992)], in which the liquid phase exhibits an average symmetry breaking similar to an h conformation, but with twisted chains, to see whether it could describe the TL phase transition. The h-h∗ model gave a value of ΔH that was too small by a factor of ˜3-4. We also predicted the temperature dependence of the 1132 cm-1 Raman band for both models, and performed measurements of the ratios of three TL Raman

  13. Nonlinear vibrational spectroscopic studies of molecular interaction and charging behavior at solid/liquid interfaces

    NASA Astrophysics Data System (ADS)

    Zhang, Luning

    Solid-liquid interfaces have been the focus of different communities of scientists due to its importance in industrial applications and chemical processes in nature. Molecular interactions and surface charges affect the physicochemical properties of these interfaces and a thorough understanding is still lacking now. This thesis describes our work in studying several model solid-liquid interfaces using sum-frequency vibrational spectroscopy. Through the studies of interfacial vibrational spectra, we hope to gain better understanding of molecular interactions in competitive adsorption process and also surface charging behavior at different pH and salt concentrations. We start by studying alcohol-water mixture and the adsorption behavior at both hydrophilic and hydrophobic surfaces. In both cases, alcohol adsorbs preferentially from water. The tendency for water to form strong hydrogen-bonding network is the driving force for preferential adsorption of alcohol. We proposed two different interfacial molecular structures on hydrophilic and hydrophobic surfaces. We move on to study the interaction of pure water with a solid surface. Single crystal alumina is used as a model system. At different pH, the surface can undergo protonation and deprotonation reactions and accumulates surface charge. Both the hydrogen-bonding with water and the surface field created by surface charge can affect interfacial water structure. Combining the information obtained with intensity and phase spectra, we find water molecules have two types of bonding within the interfacial layer: weakly hydrogen-bonded species near 3450 cm-1 that does not flip with switching surface charge, and strongly hydrogen-bonded species at 3200 cm-1 that readily flips with switching surface field. One other system we have studied is nanoporous silica-water interface. We found that signal from interfacial water is reduced due to the porous nature of the film. The water spectral features tell us about the interfacial

  14. Dynamic covalent chemistry of bisimines at the solid/liquid interface monitored by scanning tunnelling microscopy

    NASA Astrophysics Data System (ADS)

    Ciesielski, Artur; El Garah, Mohamed; Haar, Sébastien; Kovaříček, Petr; Lehn, Jean-Marie; Samorì, Paolo

    2014-11-01

    Dynamic covalent chemistry relies on the formation of reversible covalent bonds under thermodynamic control to generate dynamic combinatorial libraries. It provides access to numerous types of complex functional architectures, and thereby targets several technologically relevant applications, such as in drug discovery, (bio)sensing and dynamic materials. In liquid media it was proved that by taking advantage of the reversible nature of the bond formation it is possible to combine the error-correction capacity of supramolecular chemistry with the robustness of covalent bonding to generate adaptive systems. Here we show that double imine formation between 4-(hexadecyloxy)benzaldehyde and different α,ω-diamines as well as reversible bistransimination reactions can be achieved at the solid/liquid interface, as monitored on the submolecular scale by in situ scanning tunnelling microscopy imaging. Our modular approach enables the structurally controlled reversible incorporation of various molecular components to form sophisticated covalent architectures, which opens up perspectives towards responsive multicomponent two-dimensional materials and devices.

  15. Characterization of Solid Liquid Suspensions Utilizing Non-Invasive Ultrasonic Measurements

    SciTech Connect

    Panetta, P.D.; Tucker, B.; Ahmed, S.; Pappas, R.A.

    2004-03-31

    Rapid, on-line characterization of the particle size and concentration of moderate to highly concentrated slurries is required for efficient waste remediation at the DOE complexes. This paper discusses the advancements achieved under the Environmental Management Science Program to accurately characterize high-level waste at the high concentrations expected at the DOE complexes. In addition, the results are applicable to efficient process measurement and control in many chemical and pharmaceutical manufacturing processes. Existing methods for determining the particle size and concentration of non-dilute slurries based on ultrasonic attenuation can become inaccurate due to the complex interactions of ultrasonic waves with the constituents of the slurries and the necessity for very careful transducer alignment. Two measurements that help to overcome these difficulties are the ultrasonic backscattering and diffuse field. The backscattering measurement is attractive because viscous, thermal and inertial effects have small contributions to the backscattering. In addition, the backscattering theories are simpler than attenuation theories and lend themselves to more stable inversion processes. Furthermore, the measurements of backscattering measurement do not require long travel distances and can be made with a single transducer thus eliminating alignment problems. We will present ultrasonic measurements and theoretical comparisons on solid liquid suspensions designed to elucidate the particle size and concentration at high concentration relevant to the high level waste at the DOE complexes.

  16. Determination of pesticides in lettuce using solid-liquid extraction with low temperature partitioning.

    PubMed

    Costa, Anna I G; Queiroz, Maria E L R; Neves, Antônio A; de Sousa, Flaviane A; Zambolim, Laércio

    2015-08-15

    This work describes the optimization and validation of a method employing solid-liquid extraction with low temperature partitioning (SLE/LTP) together with analysis by gas chromatography with electron capture detection (GC/ECD) for the determination of nine pesticides (chlorothalonil, methyl parathion, procymidone, endosulfan, iprodione, λ-cyhalothrin, permethrin, cypermethrin, and deltamethrin) in lettuce. The method was found to be selective, accurate, and precise, with means recovery values in the range of 72.3-103.2%, coefficients of variation ⩽ 12%, and detection limits in the range 0.4-37 μg kg(-1). The matrix components significantly influence the chromatographic response of the analytes (above 10%). The optimized and validated method was applied to determine the residual concentrations of the fungicides iprodione and procymidone that had been applied to field crops of lettuce. The maximum residual concentrations of the pesticides in the lettuce samples were 13.6 ± 0.4 mg kg(-1) (iprodione) and 1.00 ± 0.01 mg kg(-1) (procymidone), on the day after application of the products. PMID:25794722

  17. Step free energies at faceted solid-liquid interfaces from equilibrium molecular dynamics simulations.

    PubMed

    Frolov, T; Asta, M

    2012-12-01

    In this work a method is proposed for computing step free energies for faceted solid-liquid interfaces based on atomistic simulations. The method is demonstrated in an application to (111) interfaces in elemental Si, modeled with the classical Stillinger-Weber potential. The approach makes use of an adiabatic trapping procedure, and involves simulations of systems with coexisting solid and liquid phases separated by faceted interfaces containing islands with different sizes, for which the corresponding equilibrium temperatures are computed. We demonstrate that the calculated coexistence temperature is strongly affected by the geometry of the interface. We find that island radius is inversely proportional to superheating, allowing us to compute the step free energy by fitting simulation data within the formalism of classical nucleation theory. The step free energy value is computed to be γ(st) = 0.103 ± 0.005 × 10(-10) J/m. The approach outlined in this work paves the way to the calculation of step free energies relevant to the solidification of faceted crystals from liquid mixtures, as encountered in nanowire growth by the vapor-liquid-solid mechanism and in alloy casting. The present work also shows that at low undercoolings the Stillinger-Weber interatomic potential for Si tends to crystallize in the wurtzite, rather than the diamond-cubic structure. PMID:23231218

  18. Solid Liquid Interdiffusion Bonding of Zn4Sb3 Thermoelectric Material with Cu Electrode

    NASA Astrophysics Data System (ADS)

    Lin, Y. C.; Lee, K. T.; Hwang, J. D.; Chu, H. S.; Hsu, C. C.; Chen, S. C.; Chuang, T. H.

    2016-06-01

    The ZnSb intermetallic compound may have thermoelectric applications because it is low in cost and environmentally friendly. In this study, a Zn4Sb3 thermoelectric element coated with a Ni barrier layer and a Ag reaction layer was bonded with a Ag-coated Cu electrode using a Ag/Sn/Ag solid-liquid interdiffusion bonding process. The results indicated that a Ni5Zn21 intermetallic phase formed easily at the Zn4Sb3/Ni interface, leading to sound adhesion. In addition, Sn film was found to react completely with the Ag layer to form a Ag3Sn intermetallic layer having a melting point of 480°C. The resulting Zn4Sb3 thermoelectric module can be applied at the optimized operation temperature (400°C) of Zn4Sb3 material as a thermoelectric element. The bonding strengths ranged from 14.9 MPa to 25.0 MPa, and shear tests revealed that the Zn4Sb3/Cu-joints fractured through the interior of the thermoelectric elements.

  19. Solid-liquid phase equilibrium for binary Lennard-Jones mixtures

    NASA Astrophysics Data System (ADS)

    Hitchcock, Monica R.; Hall, Carol K.

    1999-06-01

    Solid-liquid phase diagrams are calculated for binary mixtures of Lennard-Jones spheres using Monte Carlo simulation and the Gibbs-Duhem integration technique of Kofke. We calculate solid-liquid phase diagrams for the model Lennard-Jones mixtures: argon-methane, krypton-methane, and argon-krypton, and compare our simulation results with experimental data and with Cottin and Monson's recent cell theory predictions. The Lennard-Jones model simulation results and the cell theory predictions show qualitative agreement with the experimental phase diagrams. One of the mixtures, argon-krypton, has a different phase diagram than its hard-sphere counterpart, suggesting that attractive interactions are an important consideration in determining solid-liquid phase behavior. We then systematically explore Lennard-Jones parameter space to investigate how solid-liquid phase diagrams change as a function of the Lennard-Jones diameter ratio, σ11/σ22, and well-depth ratio, ɛ11/ɛ22. This culminates in an estimate of the boundaries separating the regions of solid solution, azeotrope, and eutectic solid-liquid phase behavior in the space spanned by σ11/σ22 and ɛ11/ɛ22 for the case σ11/σ22<0.85.

  20. Influence of Melt Convection on Solid-Liquid Interface Under Terrestrial and Reduced Gravity Environments

    NASA Technical Reports Server (NTRS)

    Glicksman, M. E.

    1985-01-01

    Solidification and crystal growth processes involve thermal and solutal gradients within a molten phase. In the presence of gravity, such gradients result in convective flows which interact with diffusion fields at the solid-liquid interface. Dendritic growth kinetics was studied in transparent model systems which freeze similarily to most metals. Succinonitrile shows a strong influence of convection at supercoolings below about 1K. Fluid flows adjacent to solid-liquid interfaces and the behavior of shear flows in vertical annular geometries are studied. Novel low-frequency eigenstates were discovered and classified as coupled modes, for their involvement with interfacial deformation coupled to the fluid flow, and are unknown in systems without deformable interfaces. The dependence of coupled convection modes on interfacial geometry, gravity, fluid properties, and transformation characteristics studied for several annual flow arrangements with nominally pure solid-liquid systems.

  1. Critère de fatigue polycyclique pour des matériaux anisotropes : application aux monocristaux

    NASA Astrophysics Data System (ADS)

    Cano, Florian; Constantinescu, Andrei; Maitournam, Habibou

    2004-02-01

    The high-cycle fatigue criteria based on a macroscopic-mesoscopic scale interpretation, initiated by Dang Van, were used essentially for polycrystalline materials. In the existing criteria the material isotropy at both mesoscopic and macroscopic scales plays a key role. The purpose of this paper is to revisit the macroscopic to mesoscopic fatigue approach taking into account the material anisotropy and some results obtained by Bui. The possible applications are some anisotropic steels or monocrystalline structures such as stitanium turbine blades. To cite this article: F. Cano et al., C. R. Mecanique 332 (2004).

  2. Transport Electronique Dans Les Super Reseaux : Applications Aux Détecteurs Infrarouges à Grandes Longueur D'onde

    NASA Astrophysics Data System (ADS)

    Lhuillier, Emmanuel

    2010-11-01

    The low flux infrared imaging needs performant high wavelength detectors. Quantum Well Infrared Photodetectors (QWIP), thanks to the maturity of GaAs, the possibility to adjust the detected wavelength on a large range and to realize large uniform matrix are good candidate for such applications. In order to validate this interest, we have performed an electro-optic characterization of a 15{μ}m sample. These measurements have been used to simulate the performance of a camera based on this QWIP and used in a low infrared photons flux scenario. We predict that this QWIP would succeed. Nevertheless these simulations also underline the detrimental role of the dark current. Thus we have developed a simulation tool based on a hoping approach between localized states, which provide us a better understanding of the transport in these heterostructures. The code has in particular underlines the role plays by the electron -ionized impurities interaction, which make the dark current very sensitive to the doping profile. Using this tool we have designed new structures, with optimized doping profile, in which the scattering rate has been decreased by a factor two. Moreover we have identified a quantum origin to the plateau shape of the I(V) curve. This code is more generally a useful simulation tool for the transport in hétérostructures. The influence of growth defects (non ideal interface and disorder) has been quantized and we have performed the first evaluation of The R0A in a THz QCD. Finally non local transport effects have been investigated. Saw teeth observation on the I(V) curves have been modeled and their influence on the detectivty estimated.

  3. Investigation of surface charge density on solid-liquid interfaces by modulating the electrical double layer.

    PubMed

    Moon, Jong Kyun; Song, Myung Won; Pak, Hyuk Kyu

    2015-05-20

    A solid surface in contact with water or aqueous solution usually carries specific electric charges. These surface charges attract counter ions from the liquid side. Since the geometry of opposite charge distribution parallel to the solid-liquid interface is similar to that of a capacitor, it is called an electrical double layer capacitor (EDLC). Therefore, there is an electrical potential difference across an EDLC in equilibrium. When a liquid bridge is formed between two conducting plates, the system behaves as two serially connected EDLCs. In this work, we propose a new method for investigating the surface charge density on solid-liquid interfaces. By mechanically modulating the electrical double layers and simultaneously applying a dc bias voltage across the plates, an ac electric current can be generated. By measuring the voltage drop across a load resistor as a function of bias voltage, we can study the surface charge density on solid-liquid interfaces. Our experimental results agree very well with the simple equivalent electrical circuit model proposed here. Furthermore, using this method, one can determine the polarity of the adsorbed state on the solid surface depending on the material used. We expect this method to aid in the study of electrical phenomena on solid-liquid interfaces. PMID:25923410

  4. Abatement of ammonia emissions from swine lagoons using polymer enhanced solid-liquid separation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A study was conducted to determine the effects of solid-liquid separation of liquid swine manure on ammonia emissions from lagoons. This determination was done at full-scale in two contiguous swine production units that had similar animal production management. One of these units was maintained as a...

  5. Solid-Liquid and Liquid-Liquid Mixing Laboratory for Chemical Engineering Undergraduates

    ERIC Educational Resources Information Center

    Pour, Sanaz Barar; Norca, Gregory Benoit; Fradette, Louis; Legros, Robert; Tanguy, Philippe A.

    2007-01-01

    Solid-liquid and liquid-liquid mixing experiments have been developed to provide students with a practical experience on suspension and emulsification processes. The laboratory focuses on the characterization of the process efficiency, specifically the influence of the main operating parameters and the effect of the impeller type. (Contains 2…

  6. Versatile Side-Illumination Geometry for Tip-Enhanced Raman Spectroscopy at Solid/Liquid Interfaces.

    PubMed

    Martín Sabanés, Natalia; Driessen, Leonie M A; Domke, Katrin F

    2016-07-19

    In situ characterization of surfaces with tip-enhanced Raman spectroscopy (TERS) provides chemical and topographic information with high spatial resolution and submonolayer chemical sensitivity. To further the versatility of the TERS approach toward more complex systems such as biological membranes or energy conversion devices, adaptation of the technique to solid/liquid working conditions is essential. Here, we present a home-built side-illumination TERS setup design based on a commercial scanning tunneling microscope (STM) as a versatile, cost-efficient solution for TERS at solid/liquid interfaces. Interestingly, the results obtained from showcase resonant dye and nonresonant thiophenol monolayers adsorbed on Au single crystals suggest that excitation beam aberrations due to the presence of the aqueous phase are small enough not to limit TER signal detection. The STM parameters are found to play a crucial role for solid/liquid TERS sensitivity. Raman enhancement factors of 10(5) at μW laser power demonstrate the great potential the presented experimental configuration holds for solid/liquid interfacial spectroscopic studies. PMID:27299508

  7. Enhanced solid-liquid separation of dairy manure with natural flocculants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Natural flocculants have potential to replace the use of synthetic flocculants used for enhanced solid-liquid separation of livestock effluents, especially with increased cost of energy and renewed interest on organic farming systems. We conducted a study to determine the effectiveness of natural fl...

  8. All about Solids, Liquids & Gases. Physical Science for Children[TM]. Schlessinger Science Library. [Videotape].

    ERIC Educational Resources Information Center

    2000

    In All About Solids, Liquids and Gases, young students will be introduced to the three common forms of matter. They'll learn that all things are made up of tiny particles called atoms and that the movement of these particles determines the form that matter takes. In solids, the particles are packed tightly together and move very little. The…

  9. Bionic optical imaging system with aspheric solid-liquid mixed variable-focus lens

    NASA Astrophysics Data System (ADS)

    Du, Jia-Wei; Wang, Xuan-Yin; Liang, Dan

    2016-02-01

    A bionic optical imaging system with an aspheric solid-liquid mixed variable-focus lens was designed and fabricated. The entire system mainly consisted of a doublet lens, a solid-liquid mixed variable-focus lens, a connecting part, and a CCD imaging device. To mimic the structure of the crystalline lens, the solid-liquid mixed variable-focus lens consisted of a polydimethylsiloxane (PDMS) lens, a polymethyl methacrylate lens, and the liquid of ethyl silicone oil. By pumping liquid in or out of the cavity using a microinjector, the curvatures of the front and rear surfaces of the PDMS lens were varied, resulting in a change of focal length. The overall structure of the system was presented, as well as a detailed description of the solid-liquid mixed variable-focus lens, material, and fabrication process. Under different injection volumes, the deformation of the PDMS lens was measured and simulated, pictures were captured, and the optical performance was analyzed in simulations and experiments. The focal length of the system ranged from 25.05 to 14.61 mm, and the variation of the diopter was 28.5D, which was larger than that of the human eye.

  10. Binary Solid-Liquid Phase Diagram of Phenol and t-Butanol: An Undergraduate Physical Chemistry Experiment

    ERIC Educational Resources Information Center

    Xu, Xinhua; Wang, Xiaogang; Wu, Meifen

    2014-01-01

    The determination of the solid-liquid phase diagram of a binary system is always used as an experiment in the undergraduate physical chemistry laboratory courses. However, most phase diagrams investigated in the lab are simple eutectic ones, despite the fact that complex binary solid-liquid phase diagrams are more common. In this article, the…

  11. Occurrence and solid-liquid partition of sulfonated naphthalene-formaldehyde condensates in the aquatic environment.

    PubMed

    Lange, Frank T; Merklinger, Michael; Wenz, Michael; Brauch, Heinz-J; Lehmann, Markus; Pinter, Istvan

    2005-03-15

    Sulfonated naphthalene-formaldehyde condensates (SNFC) are high production volume chemicals used in a variety of applications, for example, as concrete plasticizers, tanning agents, or dye dispersants. They enter the aquatic environment primarily by the wastewater path. The occurrence and fate of the monomers, which are different isomers of mono- and disulfonated naphthalene, was intensively investigated in previous studies. However, the environmental fate of the persistent higher molecular SNFC is so far widely unknown. This paper describes an ultrasonic extraction under alkaline conditions, followed by ion-pair HPLC with fluorescence detection for the analysis of SNFC oligomers from solid environmental matrixes such as sewage sludge, suspended solids, and river sediments. Limits of quantification of about 0.1 mg kg-1 d.m. were well below the measured concentrations in environmental samples. SNFC were adsorbed to suspended solids and river sediments in three major German rivers (Rhine, Neckar, and Danube) in concentrations typically up to several mg kg(-1) d.m. A total content of about 4 g kg(-1) d.m. was measured in a sewage sludge of a municipal wastewater treatment plant, which receives wastewater from a textile dyeing plant. Furthermore, the first quantitative field data on the partition of SNFC and their monomers between the aqueous phase and solid environmental compartments are presented. Solid-liquid partition coefficients (Kd) of oligomers with a chain-length ranging from three to six naphthalenesulfonate units were derived from the analysis of corresponding wastewater and sewage sludge samples and from suspended solids and river water samples, respectively. Determined Kd values were in the range from 10(2) to 10(4) L kg(-1). PMID:15819205

  12. Solid-liquid separation for liquefied coal industries. Final report

    SciTech Connect

    Tiller, F.M.; Leu, W.

    1984-07-01

    This book has been written for engineers concerned with separation processes related to liquefied coal slurries. Difficulties in removing mineral residues and unconverted carbon represent a major obstacle to economic production of liquefied coal products. Reactor slurries in which hydrogenation has been used to upgrade coal generally contain 5 to 10 weight percents of solids which must be removed. Various kinds of equipment employed for particulate removal include rotary drum pressure, candle, and leaf filters, solid bowl centrifuges, hydrocyclones, and critical solvent de-ashers. Although emphasis has been given to filtration of solvent refined coal, much of the material is of a fundamental character and is applicable to other fields. Analysis of filtration data requires an understanding of the principles of frictional flow through compressible beds of particulates. Much of the analysis appearing in the literature must be carefully evaluated as errors and misinterpretations abound.

  13. Adsorption of R-OH molecules on TiO2 surfaces at the solid-liquid interface.

    PubMed

    Sánchez, Verónica M; de la Llave, Ezequiel; Scherlis, Damian A

    2011-03-15

    The exploration of TiO2 surface reactivity from first-principles calculations has been almost always limited to the gas phase, even though most of the chemically relevant applications of this interface involve the solid-liquid boundary. The reason for this limitation is the complexity of the solid-liquid interface, which poses a serious challenge to standard ab initio methodologies as density functional theory (DFT). In this work we study the interaction of H2O, CH3OH, H2O2, and HCO2H with anatase (101) and rutile (110) surfaces in aqueous solution, employing a continuum solvation model in a DFT framework in periodic boundary conditions [ J. Chem. Phys. 2009 , 131 , 174108 ]. Different adsorption configurations were analyzed, examining the effect of the first water monolayer explicitly included in the simulation. For water and methanol, molecular adsorption was found to be the most stable in the presence of the solvent, while for hydrogen peroxide the preferred configuration depended on the surface. The explicit inclusion of the first water monolayer turns out to be important since it may play a role in the stabilization of the adsorbates at the interface. In general, the slightly positive adsorption energy values obtained (with respect to water) suggest that CH3OH and H2O2 will poorly adsorb from an aqueous solution at the titania surface. Among the three species investigated other than water, the formic acid was the only one to exhibit a higher affinity for the surface than H2O. PMID:21314168

  14. Flowing Foam: T1 events and solid-liquid transitions.

    NASA Astrophysics Data System (ADS)

    Dennin, Michael

    2005-11-01

    Flowing aqueous foam is found in many applications ranging from oil recovery, to fire fighting, to spreading shaving cream. Aqueous foam consists of gas bubbles with liquid walls. One of the striking features of foam is that despite being composed entirely of fluids, its mechanical properties are either those of a solid (elastic response) or fluid (viscous flow), depending on the nature of the applied stress and strains. We study the transition between these two regimes using a model foam system: bubble rafts. Bubble rafts are a single layer of bubbles floating on the air-water surface. This allows us to track the motion of all the bubbles during flow. In this talk, we will present two main results. First, we will discuss the observation of the coexistence between a solid-like and fluid-like state during flow. Second, we will discuss the role played by nonlinear, topological rearrangements, known as T1 events, in determining the mechanical response of the system.

  15. Performance analysis on solid-liquid mixed flow in a centrifugal pump

    NASA Astrophysics Data System (ADS)

    Ning, C.; Wang, Y.

    2016-05-01

    In order to study the solid-liquid mixed flow hydraulic characteristics of centrifugal pump, the Pro/E software was used for three-dimensional modeling of centrifugal pump chamber. By using the computational fluid dynamics software CFX, the numerical simulation calculation of solid-liquid two-phase flow within whole flow passage of centrifugal pump was conducted. Aim at different particle diameters, the Reynolds-averaged N-S equations with the RNG k-Ɛ turbulence model and SIMPLEC algorithm were used to simulate the two-phase flow respectively on the condition of different volume fraction. The influence of internal flow characteristic on pump performance was analyzed. On the conditions of different particle diameter and different volume fraction, the turbulence kinetic energy and particle concentration are analyzed. It can be found that the erosion velocity ratio on the flow channel wall increases along with the increasing of the volume fraction

  16. Thermodynamic and rheological properties of solid-liquid systems in coal processing

    SciTech Connect

    Kabadi, V.N.; Ilias, S.

    1992-01-01

    In this report we present two data sets that have been compiled to assist in the model developments for solid-liquid equilibria and viscosities of coal derived systems. The first one is on vapor pressures of solid aromatics and the second one consists of viscosities of pure model compounds and some mixtures. These databanks are ready for usage in model development and are summarized in Tables 1 and 2. Literature is being searched to compile similar data for high pressure liquid compressibilities, liquid and solid heat capacities and solid-liquid equilibria for model compound systems. Literature search is also containing to investigate available viscosity models. Once this is completed a few models will be selected for evaluation and consideration as candidates for extension to coal liquids.

  17. Numerical simulation of solid liquid interface behavior during continuous strip casting process.

    PubMed

    Lee, Changbum; Yoon, Wooyoung; Shin, Seungwon; Lee, Jaewoo; Jang, Bo-Yun; Kim, Joonsoo; Ahn, Youngsoo; Lee, Jinseok

    2013-05-01

    A new metal-strip-casting process called continuous strip-casting (CSC) has been developed for making thin metal strips. A numerical simulation model to help understand solid-liquid interface behavior during CSC has been developed and used to identify the solidification morphologies of the strips and to determine the optimum processing conditions. In this study, we used a modified level contour reconstruction method (LCRM) and the sharp interface method to modify interface tracking, and performed a simulation analysis of the CSC process. The effects of process parameters such as heat-transfer coefficient and extrusion velocity on the behavior of the solid-liquid interface were estimated and used to improve the apparatus. A Sn (Tin) plate of dimensions 200 x 50 x 1 mm3 was successfully produced by CSC for a heat-transfer coefficient of 104 W/m2 K and an extrusion velocity of 0.2 m/s. PMID:23858856

  18. Numerical formulation of composition segregation at curved solid-liquid interface during steady state solidification process

    NASA Technical Reports Server (NTRS)

    Wang, Jai-Ching

    1994-01-01

    The lateral solute segregation that results from a curved solid-liquid interface shape during steady state unidirectional solidification of a binary alloy system has been studied both analytically and numerically by Coriell, Bosivert, Rehm, and Sekerka. The system under their study is a two dimensional rectangular system. However, most real growth systems are cylindrical systems. Thus, in a previous study, we have followed Coriell etc. formalism and obtained analytical results for lateral solute segregation for an azimuthal symmetric cylindrical binary melt system during steady state solidification process. The solid-liquid interface shape is expressed as a series combination of Bessel functions. In this study a computer program has been developed to simulate the lateral solute segregation.

  19. Interaction of Porosity with an Advancing Solid/Liquid Interface: a Real-Time Investigation

    NASA Technical Reports Server (NTRS)

    Sen, S.; Kaukler, W.; Catalina, A.; Stefanescu, D.; Curreri, P.

    1999-01-01

    Problems associated with formation of porosity during solidification continue to have a daily impact on the metal forming industry. Several past investigations have dealt with the nucleation and growth aspects of porosity. However, investigations related to the interaction of porosity with that of a solidification front has been limited mostly to organic analogues. In this paper we report on real time experimental observations of such interactions in metal alloys. Using a state of the art X-Ray Transmission Microscope (XTM) we have been able to observe and record the dynamics of the interaction. This includes distortion of the solid/liquid interface near a poro.sity, solute segr,egation patterns surrounding a porosity and the change in shape of the porosity during interaction with an advancing solid/liquid interface. Results will be presented for different Al alloys and growth conditions. The experimental data will be compared to theory using a recently developed 2D numerical model. The model employs a finite difference approach where the solid/liquid interface is defined through the points at which the interface intersects the grid lines. The transport variables are calculated at these points and the motion of the solidification front is determined by the magnitude of the transport variables. The model accounts for the interplay of the thermal and solutal field and the influence of capilarity to predict the shape of the solid/liquid interface with time in the vicinity of porosity. One can further calculate the perturbation of the solutal field by the presence of porosity in the melt.

  20. Note: Sample cells to investigate solid/liquid interfaces with neutrons

    SciTech Connect

    Rennie, Adrian R. Hellsing, Maja S.; Lindholm, Eric; Olsson, Anders

    2015-01-15

    The design of sample cells to study solid/liquid interfaces by neutron reflection is presented. Use of standardized components and a modular design has allowed a wide range of experiments that include grazing incidence scattering and conventional small-angle scattering. Features that reduce background scattering are emphasized. Various flow arrangements to fill and replenish the liquid in the cell as well as continuous stirring are described.

  1. Correlation among the laser-induced breakdown thresholds in solids, liquids, and gases.

    PubMed

    Bettis, J R

    1992-06-20

    A simple expression is developed that permits a correlation among laser-induced breakdown thresholds in solids, liquids, and gases. It is shown that the breakdown thresholds for the bulk of solid dielectrics, linear liquids, and gases all follow a linear fit to the expression N(2/3)/(n(2) - 1), where N is the atomic number density and n is the refractive index. The gas breakdown threshold versus pressure is compared with the predicted dependence. PMID:20725310

  2. A new continuous device to perform S-L-G photocatalytic studies. [Solid-Liquid-Gas

    SciTech Connect

    Aguado, M.A.; Gimenez, J.; Simarro, R.; Cervera-March, S. )

    1992-07-01

    A new experimental device to carry out solid-liquid-gas photocatalytic studies is presented. It can operate as a continuous system with respect to both the gas and the liquid phase. The solid photocatalyst is held inside the system and is continuously recycled through it to enable the separation of the spent liquid. Steady values of liquid and gas composition as well as temperature and fluidodynamic variables can be set and controlled.

  3. Effect of confinement on the solid-liquid coexistence of Lennard-Jones Fluid

    SciTech Connect

    Das, Chandan K.; Singh, Jayant K.

    2013-11-07

    The solid-liquid coexistence of a Lennard-Jones fluid confined in slit pores of variable pore size, H, is studied using molecular dynamics simulations. Three-stage pseudo-supercritical transformation path of Grochola [J. Chem. Phys. 120(5), 2122 (2004)] and multiple histogram reweighting are employed for the confined system, for various pore sizes ranging from 20 to 5 molecular diameters, to compute the solid-liquid coexistence. The Gibbs free energy difference is evaluated using thermodynamic integration method by connecting solid-liquid phases under confinement via one or more intermediate states without any first order phase transition among them. Thermodynamic melting temperature is found to oscillate with wall separation, which is in agreement with the behavior seen for kinetic melting temperature evaluated in an earlier study. However, thermodynamic melting temperature for almost all wall separations is higher than the bulk case, which is contrary to the behavior seen for the kinetic melting temperature. The oscillation founds to decay at around H = 12, and beyond that pore size dependency of the shift in melting point is well represented by the Gibbs-Thompson equation.

  4. Real-time single-molecule observations of proteins at the solid-liquid interface

    NASA Astrophysics Data System (ADS)

    Langdon, Blake Brianna

    Non-specific protein adsorption to solid surfaces is pervasive and observed across a broad spectrum of applications including biomaterials, separations, pharmaceuticals, and biosensing. Despite great interest in and considerable literature dedicated to the phenomena, a mechanistic understanding of this complex phenomena is lacking and remains controversial, partially due to the limits of ensemble-averaging techniques used to study it. Single-molecule tracking (SMT) methods allow us to study distinct protein dynamics (e.g. adsorption, desorption, diffusion, and intermolecular associations) on a molecule-by-molecule basis revealing the protein population and spatial heterogeneity inherent in protein interfacial behavior. By employing single-molecule total internal reflection fluorescence microscopy (SM-TIRFM), we have developed SMT methods to directly observe protein interfacial dynamics at the solid-liquid interface to build a better mechanistic understanding of protein adsorption. First, we examined the effects of surface chemistry (e.g. hydrophobicity, hydrogen-bonding capacity), temperature, and electrostatics on isolated protein desorption and interfacial diffusion for fibrinogen (Fg) and bovine serum albumin (BSA). Next, we directly and indirectly probed the effects of protein-protein interactions on interfacial desorption, diffusion, aggregation, and surface spatial heterogeneity on model and polymeric thin films. These studies provided many useful insights into interfacial protein dynamics including the following observations. First, protein adsorption was reversible, with the majority of proteins desorbing from all surface chemistries within seconds. Isolated protein-surface interactions were relatively weak on both hydrophobic and hydrophilic surfaces (apparent desorption activation energies of only a few kBT). However, proteins could dynamically and reversibly associate at the interface, and these interfacial associations led to proteins remaining on the

  5. Electrical impedance tomography spectroscopy method for characterising particles in solid-liquid phase

    NASA Astrophysics Data System (ADS)

    Zhao, Yanlin; Wang, Mi; Yao, Jun

    2014-04-01

    Electrical impedance tomography (EIT) is one of the process tomography techniques to provide an on-line non-invasive imaging for multiphase flow measurement. With EIT measurements, the images of impedance real part, impedance imaginary part, phase angle, and magnitude can be obtained. However, most of the applications of EIT in the process industries rely on the conductivity difference between two phases in fluids to obtain the concentration profiles. It is not common to use the imaginary part or phase angle due to the dominant change in conductivity or complication in the use of other impedance information. In a solid-liquid two phases system involving nano- or submicro-particles, characterisation of particles (e.g. particle size and concentration) have to rely on the measurement of impedance phase angle or imaginary part. Particles in a solution usually have an electrical double layer associated with their surfaces and can form an induced electrical dipole moment due to the polarization of the electrical double layer under the influence of an alternating electric field. Similar to EIT, electrical impedance spectroscopy (EIS) measurement can record the electrical impedance data, including impedance real part, imaginary part and phase angle (θ), which are caused by the polarization of the electrical double layer. These impedance data are related to the particle characteristics e.g. particle size, particle and ionic concentrations in the aqueous medium, therefore EIS method provides a capability for characterising the particles in suspensions. Electrical impedance tomography based on EIS measurement or namely, electrical impedance tomography spectroscopy (EITS) could image the spatial distribution of particle characteristics. In this paper, a new method, including test set-up and data analysis, for characterisation of particles in suspensions are developed through the experimental approach. The experimental results on tomographic imaging of colloidal particles

  6. Electrical impedance tomography spectroscopy method for characterising particles in solid-liquid phase

    SciTech Connect

    Zhao, Yanlin; Wang, Mi; Yao, Jun

    2014-04-11

    Electrical impedance tomography (EIT) is one of the process tomography techniques to provide an on-line non-invasive imaging for multiphase flow measurement. With EIT measurements, the images of impedance real part, impedance imaginary part, phase angle, and magnitude can be obtained. However, most of the applications of EIT in the process industries rely on the conductivity difference between two phases in fluids to obtain the concentration profiles. It is not common to use the imaginary part or phase angle due to the dominant change in conductivity or complication in the use of other impedance information. In a solid-liquid two phases system involving nano- or submicro-particles, characterisation of particles (e.g. particle size and concentration) have to rely on the measurement of impedance phase angle or imaginary part. Particles in a solution usually have an electrical double layer associated with their surfaces and can form an induced electrical dipole moment due to the polarization of the electrical double layer under the influence of an alternating electric field. Similar to EIT, electrical impedance spectroscopy (EIS) measurement can record the electrical impedance data, including impedance real part, imaginary part and phase angle (θ), which are caused by the polarization of the electrical double layer. These impedance data are related to the particle characteristics e.g. particle size, particle and ionic concentrations in the aqueous medium, therefore EIS method provides a capability for characterising the particles in suspensions. Electrical impedance tomography based on EIS measurement or namely, electrical impedance tomography spectroscopy (EITS) could image the spatial distribution of particle characteristics. In this paper, a new method, including test set-up and data analysis, for characterisation of particles in suspensions are developed through the experimental approach. The experimental results on tomographic imaging of colloidal particles

  7. Conception, elaboration et mise a l'essai d'un simulateur interactif permettant une approche modelisante: Application aux lois de la genetique mendelienne

    NASA Astrophysics Data System (ADS)

    Lasri, Abdel-Halim

    Dans cette recherche-developpement, nous avons concu, developpe et mis a l'essai un simulateur interactif pour favoriser l'apprentissage des lois probabilistes impliqees dans la genetique mendelienne. Cet environnement informatise devra permettre aux etudiants de mener des experiences simulees, utilisant les statistiques et les probebilites comme outils mathematiques pour modeliser le phenomene de la transmission des caracteres hereditaires. L'approche didactique est essentiellement orientee vers l'utilisation des methodes quantitatives impliquees dans l'experimentation des facteurs hereditaires. En incorporant au simulateur le principe de la "Lunette cognitive" de Nonnon (1986), l'etudiant fut place dans une situation ou il a pu synchroniser la perception de la representation iconique (concrete) et symbolique (abstraite) des lois probabilistes de Mendel. A l'aide de cet environnement, nous avons amene l'etudiant a identifier le(s) caractere(s) hereditaire(s) des parents a croiser, a predire les frequences phenotypiques probables de la descendance issue du croisement, a observer les resultats statistiques et leur fluctuation au niveau de l'histogramme des frequences, a comparer ces resultats aux predictions anticipees, a interpreter les donnees et a selectionner en consequence d'autres experiences a realiser. Les etapes de l'approche inductive sont privilegiees du debut a la fin des activites proposees. L'elaboration, du simulateur et des documents d'accompagnement, a ete concue a partir d'une vingtaine de principes directeurs et d'un modele d'action. Ces principes directeurs et le modele d'action decoulent de considerations theoriques psychologiques, didactiques et technologiques. La recherche decrit la structure des differentes parties composant le simulateur. L'architecture de celui-ci est construite autour d'une unite centrale, la "Principale", dont les liens et les ramifications avec les autres unites confere a l'ensemble du simulateur sa souplesse et sa

  8. On the solute coupling at the moving solid/liquid interface during equiaxed solidification

    NASA Astrophysics Data System (ADS)

    Yao, X.

    2006-08-01

    Integral mass conservation was widely accepted for the solute coupling to solve solute redistribution during equiaxed solidification so far. The present study revealed that the integral form was invalid for moving boundary problems as it could not represent the mass balance at the moving interface. Accordingly, differential mass conservation at the solid/liquid interface was used to solve solute diffusion for spherical geometry. The model was applied for hydrogen diffusion in solidification to validate that the hydrogen enrichment was significant and depended on the growth rate.

  9. Detection of elastic modes in a solid-liquid-solid planar waveguide

    NASA Astrophysics Data System (ADS)

    Ham-Rodriguez, C. I.; Manzanares-Martinez, J.; Moctezuma-Enriquez, D.; Manzanares-Martinez, B.

    2016-08-01

    In this work, we demonstrate that acoustic ultra-short pulses can be used to characterize multiple guided modes in a solid-liquid-solid planar waveguide via the determination of the time of flight (τ) using the Short Time Fourier Transform (STFT). To obtain experimentally τ, we introduce a time dependent ultra-short acoustic signal s(t) at one side of a finite waveguide and we perform the STFT of the outgoing acoustic signal s'(t) from the other side. We have found that this technique is able to discriminate the signature of multiple even and odd modes at the same experimental run.

  10. Determination of the mean solid-liquid interface energy of pivalic acid

    NASA Technical Reports Server (NTRS)

    Singh, N. B.; Gliksman, M. E.

    1989-01-01

    A high-confidence solid-liquid interfacial energy is determined for an anisotropic material. A coaxial composite having a cylindrical specimen chamber geometry provides a thermal gradient with an axial heating wire. The surface energy is derived from measurements of grain boundary groove shapes. Applying this method to pivalic acid, a surface energy of 2.84 erg/sq cm was determined with a total systematic and random error less than 10 percent. The value of interfacial energy corresponds to 24 percent of the latent heat of fusion per molecule.

  11. The Discrete Multi-Hybrid System for the Simulation of Solid-Liquid Flows

    PubMed Central

    Alexiadis, Alessio

    2015-01-01

    This study proposes a model based on the combination of Smoothed Particle Hydrodynamics, Coarse Grained Molecular Dynamics and the Discrete Element Method for the simulation of dispersed solid-liquid flows. The model can deal with a large variety of particle types (non-spherical, elastic, breakable, melting, solidifying, swelling), flow conditions (confined, free-surface, microscopic), and scales (from microns to meters). Various examples, ranging from biological fluids to lava flows, are simulated and discussed. In all cases, the model captures the most important features of the flow. PMID:25961561

  12. Distribution of solute at solid-liquid interface during solidification of melt

    NASA Astrophysics Data System (ADS)

    Fukui, Keisuke; Maeda, Kouji

    1998-11-01

    A model for predicting a distribution coefficient (ki) of solute at the solid-liquid (S-L) interface, when the solid layer is growing, is proposed. The interfacial distribution coefficient is expressed as a function of two gradients of the liquid concentration and equilibrium concentration at the S-L interface. The model is applied to the solidification of a simple eutectic binary liquid of lauric acid and myristic acid in an enclosed rectangular box in which a vertical wall is cooled. The impurity-concentration profile in solid is predicted from the direct numerical computations.

  13. Synthesis of gold-silica composite nanowires through solid-liquid-solid phase growth.

    PubMed

    Paulose, Maggie; Varghese, Oomman K; Grimes, Craig A

    2003-08-01

    Nanoscale wires of silicon oxide, and silicon oxide with embedded gold-silicide nanospheres, are synthesized by heating of a gold-coated silicon wafer at temperatures of 1000 degrees C or above, with the resulting wires having diameters ranging from 30 to 150 nm and lengths of approximately 1 mm. This simple fabrication process should make possible economical bulk production of nanowires. Studies indicate that the growth of these gold-silica composite nanowires occurs directly on the silicon wafer by a solid-liquid-solid mechanism. PMID:14598450

  14. Surface-induced selection during in situ photoswitching at the solid/liquid interface.

    PubMed

    Bonacchi, Sara; El Garah, Mohamed; Ciesielski, Artur; Herder, Martin; Conti, Simone; Cecchini, Marco; Hecht, Stefan; Samorì, Paolo

    2015-04-13

    Here we report for the first time a submolecularly resolved scanning tunneling microscopy (STM) study at the solid/liquid interface of the in situ reversible interconversion between two isomers of a diarylethene photoswitch, that is, open and closed form, self-assembled on a graphite surface. Prolonged irradiation with UV light led to the in situ irreversible formation of another isomer as by-product of the reaction, which due to its preferential physisorption accumulates at the surface. By making use of a simple yet powerful thermodynamic model we provide a quantitative description for the observed surface-induced selection of one isomeric form. PMID:25728405

  15. Pressure cell for investigations of solid-liquid interfaces by neutron reflectivity

    NASA Astrophysics Data System (ADS)

    Kreuzer, Martin; Kaltofen, Thomas; Steitz, Roland; Zehnder, Beat H.; Dahint, Reiner

    2011-02-01

    We describe an apparatus for measuring scattering length density and structure of molecular layers at planar solid-liquid interfaces under high hydrostatic pressure conditions. The device is designed for in situ characterizations utilizing neutron reflectometry in the pressure range 0.1-100 MPa at temperatures between 5 and 60 °C. The pressure cell is constructed such that stratified molecular layers on crystalline substrates of silicon, quartz, or sapphire with a surface area of 28 cm2 can be investigated against noncorrosive liquid phases. The large substrate surface area enables reflectivity to be measured down to 10-5 (without background correction) and thus facilitates determination of the scattering length density profile across the interface as a function of applied load. Our current interest is on the stability of oligolamellar lipid coatings on silicon surfaces against aqueous phases as a function of applied hydrostatic pressure and temperature but the device can also be employed to probe the structure of any other solid-liquid interface.

  16. Pressure cell for investigations of solid-liquid interfaces by neutron reflectivity.

    PubMed

    Kreuzer, Martin; Kaltofen, Thomas; Steitz, Roland; Zehnder, Beat H; Dahint, Reiner

    2011-02-01

    We describe an apparatus for measuring scattering length density and structure of molecular layers at planar solid-liquid interfaces under high hydrostatic pressure conditions. The device is designed for in situ characterizations utilizing neutron reflectometry in the pressure range 0.1-100 MPa at temperatures between 5 and 60 °C. The pressure cell is constructed such that stratified molecular layers on crystalline substrates of silicon, quartz, or sapphire with a surface area of 28 cm(2) can be investigated against noncorrosive liquid phases. The large substrate surface area enables reflectivity to be measured down to 10(-5) (without background correction) and thus facilitates determination of the scattering length density profile across the interface as a function of applied load. Our current interest is on the stability of oligolamellar lipid coatings on silicon surfaces against aqueous phases as a function of applied hydrostatic pressure and temperature but the device can also be employed to probe the structure of any other solid-liquid interface. PMID:21361606

  17. Convective influence on the stability of a cylindrical solid-liquid interface

    NASA Technical Reports Server (NTRS)

    Fang, Q. T.; Glicksman, M. E.; Coriell, S. R.; Mcfadden, G. B.; Boisvert, R. F.

    1985-01-01

    Experiments in which a long vertical, heated wire is surrounded by concentric annuli of a melt and its crystalline solid show that the convection state changes from a stable unicell surrounded by a stationary cylindrical solid-liquid interface, to a complex time-dependent flow surrounded by a rotating, helical solid-liquid interface. This transition occurs at a Grashof number of approximately 150, which is an order of magnitude less than the critical Grashof number calculated for a liquid annulus surrounded by rigid walls. A linear stability analysis has been carried out for an infinitely tall vertical annulus. When the deformable nature of the crystal-melt interface is taken into account in the boundary conditions, two new modes of instability arise. The most dangerous mode is asymmetrical and corresponds to helical waves travelling vertically upwards. The critical Grashof number and the scaling properties of the eigenstate agree with experiments. The results clearly demonstrate the coupling of convection with crystal-melt interfacial instabilities.

  18. Modified phase-field-crystal model for solid-liquid phase transitions

    NASA Astrophysics Data System (ADS)

    Guo, Can; Wang, Jincheng; Wang, Zhijun; Li, Junjie; Guo, Yaolin; Tang, Sai

    2015-07-01

    A modified phase-field-crystal (PFC) model is proposed to describe solid-liquid phase transitions by reconstructing the correlation function. The effects of fitting parameters of our modified PFC model on the bcc-liquid phase diagram, numerical stability, and solid-liquid interface properties during planar interface growth are examined carefully. The results indicate that the increase of the correlation function peak width at k =km will enhance the stability of the ordered phase, while the increase of peak height at k =0 will narrow the two-phase coexistence region. The third-order term in the free-energy function and the short wave-length of the correlation function have significant influences on the numerical stability of the PFC model. During planar interface growth, the increase of peak width at k =km will decrease the interface width and the velocity coefficient C , but increase the anisotropy of C and the interface free energy. Finally, the feasibility of the modified phase-field-crystal model is demonstrated with a numerical example of three-dimensional dendritic growth of a body-centered-cubic structure.

  19. Modified phase-field-crystal model for solid-liquid phase transitions.

    PubMed

    Guo, Can; Wang, Jincheng; Wang, Zhijun; Li, Junjie; Guo, Yaolin; Tang, Sai

    2015-07-01

    A modified phase-field-crystal (PFC) model is proposed to describe solid-liquid phase transitions by reconstructing the correlation function. The effects of fitting parameters of our modified PFC model on the bcc-liquid phase diagram, numerical stability, and solid-liquid interface properties during planar interface growth are examined carefully. The results indicate that the increase of the correlation function peak width at k=k(m) will enhance the stability of the ordered phase, while the increase of peak height at k=0 will narrow the two-phase coexistence region. The third-order term in the free-energy function and the short wave-length of the correlation function have significant influences on the numerical stability of the PFC model. During planar interface growth, the increase of peak width at k=k(m) will decrease the interface width and the velocity coefficient C, but increase the anisotropy of C and the interface free energy. Finally, the feasibility of the modified phase-field-crystal model is demonstrated with a numerical example of three-dimensional dendritic growth of a body-centered-cubic structure. PMID:26274309

  20. Evaluation and ranking of the tank focus area solid liquid separation needs

    SciTech Connect

    McCabe, D.J.

    1995-08-17

    The Tank Focus Area (TFA) of the Department of Energy (DOE) Office of Environmental Restoration and Waste Management (EM) addresses remediation of liquid waste currently stored in underground tanks. Several baseline technologies for treatment of tank waste can be categorized into three types of solid liquid separation: (a) removal of radioactive species that have been absorbed or precipitated, (b) pretreatment for ion exchange, and (c) volume reduction of sludge and wash water. The solids formed from precipitation or absorption of radioactive ions require separation from the liquid phase to permit treatment of the liquid as Low Level Waste. Prior to ion exchange of radioactive ions, removal of insoluble solids is needed to prevent bed fouling and downstream contamination. Volume reduction of washed sludge solids would reduce the tank space required for interim storage. The scope of this document is to evaluate the solid/liquid separations needed to permit treatment of tank wastes to accomplish these goals. The document summarizes previous alkaline waste testing, with an emphasis on crossflow filtration, to-obtain a general understanding of the behavior of radioactive wastes on available equipment. The document also provides general information about filtration and a path forward for testing.

  1. A level set method for solid-liquid interface tracking in texturally equilibrated pore networks

    NASA Astrophysics Data System (ADS)

    Ghanbarzadeh, Soheil; Hesse, Marc; Prodanovic, Masa

    2015-04-01

    The properties of some porous media are determined by their evolution towards textural equilibrium. Melt drainage from temperate glacier ice and the accumulation of hydrocarbons beneath rock salt are two examples in natural systems. In these materials, pore geometry evolves to minimize the solid-liquid interfacial energy while maintaining dihedral angle, θ, at solid-liquid contact lines. In this work we present the first computations of 3-D texturally equilibrated pore networks using a novel level set method. Interfacial energy minimization is achieved by evolving interface under surface diffusion to constant mean curvature surface. The porosity and dihedral angle constraints are added to the formulation using virtual velocity terms. A domain decomposition scheme is devised to restrict the computational domain and the coupling between the interfaces is achieved on the original computational domain. For the last 30 years, explicit representation of the interfaces limited the computations to highly idealized geometries. The presented model overcomes these limitations and opens the door to the exploration of the physics of these materials in realistic systems. For example, our results show that the fully wetted grain boundaries exist even for θ>0 which reconciles the theory with experimental observations. This work is sponsored by the Statoil Fellows Program at The University of Texas.

  2. Monitoring the solid-liquid interface in tanks using profiling sonar and 3D visualization techniques

    NASA Astrophysics Data System (ADS)

    Sood, Nitin; Zhang, Jinsong; Roelant, David; Srivastava, Rajiv

    2005-03-01

    Visualization of the interface between settled solids and the optically opaque liquid above is necessary to facilitate efficient retrieval of the high-level radioactive waste (HLW) from underground storage tanks. A profiling sonar was used to generate 2-D slices across the settled solids at the bottom of the tank. By incrementally rotating the sonar about its centerline, slices of the solid-liquid interface can be imaged and a 3-D image of the settled solids interface generated. To demonstrate the efficacy of the sonar in real-time solid-liquid interface monitoring systems inside HLW tanks, two sets of experiments were performed. First, various solid objects and kaolin clay (10 μm dia) were successfully imaged while agitating with 30% solids (by weight) entrained in the liquid. Second, a solid with a density similar to that of the immersed fluid density was successfully imaged. Two dimensional (2-D) sonar images and the accuracy and limitations of the in-tank imaging will be presented for these two experiments. In addition, a brief review of how to utilize a 2-D sonar image to generate a 3-D surface of the settled layer within a tank will be discussed.

  3. A New Paradigm of Computer Graphics by Universal Solver for Solid, Liquid and Gas

    NASA Astrophysics Data System (ADS)

    Yabe, Takashi; Takizawa, Kenji; Xiao, Feng; Aoki, Takayuki; Himeno, Takehiro; Takahashi, Tsunemi; Kunimatsu, Atsushi

    We propose a new algorithm for producing computer graphics of melting and evaporation process of matter. Such a computation becomes possible by a universal solver for solid, liquid and gas based on the CIP (Cubic-Interpolated Propagation / Constrained Interpolation Profile) method proposed by one of the authors. This method can also be applied to the movement, deformation and even break up of solid, liquid and gas in one simple algorithm. Therefore seamless computation of all the phases of matter becomes possible. This enables us to reproduce natural phenomena in some instances by computation. In order to demonstrate this reality, we show how precisely the computational result replicates the movies of real phenomena. The flattering motions of metal disk in water and thin name card in air are treated showing accuracy of force calculation on the surface of sub-grid scale. Although the CIP uses semi-Lagrangian form algorithm, the exact mass conservation is guaranteed by additional tool. By using this scheme, separation of a bubble in bifurcation tube and splashing of water surface are successfully simulated.

  4. Kerr-AdS analogue of triple point and solid/liquid/gas phase transition

    NASA Astrophysics Data System (ADS)

    Altamirano, Natacha; Kubizňák, David; Mann, Robert B.; Sherkatghanad, Zeinab

    2014-02-01

    We study the thermodynamic behavior of multi-spinning d = 6 Kerr-anti de Sitter black holes in the canonical ensemble of fixed angular momenta J1 and J2. We find, dependent on the ratio q = J2/J1, qualitatively different interesting phenomena known from the ‘every day thermodynamics’ of simple substances. For q = 0 the system exhibits recently observed reentrant large/small/large black hole phase transitions, but for 0 < q ≪ 1 we find an analogue of a ‘solid/liquid’ phase transition. Furthermore, for q ∈ (0.00905, 0.0985) the system displays the presence of a large/intermediate/small black hole phase transition with two critical and one triple (or tricritical) points. This behavior is reminiscent of the solid/liquid/gas phase transition except that the coexistence line of small and intermediate black holes does not continue for an arbitrary value of pressure (similar to the solid/liquid coexistence line) but rather terminates at one of the critical points. Finally, for q > 0.0985 we observe the ‘standard liquid/gas behavior’ of the Van der Waals fluid.

  5. Investigating the solid-liquid phase transition of water nanofilms using the generalized replica exchange method

    SciTech Connect

    Lu, Qing; Kim, Jaegil; Straub, John E.; Farrell, James D.; Wales, David J.

    2014-11-14

    The generalized Replica Exchange Method (gREM) was applied to study a solid-liquid phase transition in a nanoconfined bilayer water system using the monatomic water (mW) model. Exploiting optimally designed non-Boltzmann sampling weights with replica exchanges, gREM enables an effective sampling of configurations that are metastable or unstable in the canonical ensemble via successive unimodal energy distributions across phase transition regions, often characterized by S-loop or backbending in the statistical temperature. Extensive gREM simulations combined with Statistical Temperature Weighted Histogram Analysis Method (ST-WHAM) for nanoconfined mW water at various densities provide a comprehensive characterization of diverse thermodynamic and structural properties intrinsic to phase transitions. Graph representation of minimized structures of bilayer water systems determined by the basin-hopping global optimization revealed heterogeneous ice structures composed of pentagons, hexagons, and heptagons, consistent with an increasingly ordered solid phase with decreasing density. Apparent crossover from a first-order solid-liquid transition to a continuous one in nanoconfined mW water with increasing density of the system was observed in terms of a diminishing S-loop in the statistical temperature, smooth variation of internal energies and heat capacities, and a characteristic variation of lateral radial distribution functions, and transverse density profiles across transition regions.

  6. Digital microfluidics platform for interfacing solid-liquid extraction column with portable capillary electropherograph for analysis of soil amino acids.

    PubMed

    Gorbatsova, Jelena; Jaanus, Martin; Vaher, Merike; Kaljurand, Mihkel

    2016-02-01

    In this work, the concept of a field-portable analyzer is proposed that operates with milliliter amounts of solvents and samples. The need to develop such an analyzer is not only driven by specific extraterrestrial analysis but also, for example, by forensics applications where the amount of liquid that can be taken to the field is severely limited. The prototype of the proposed analyzer consists of a solid-liquid extractor, the output of which is connected to the micropump, which delivers droplets of extracts to digital microfluidic platform (DMFP). In this way, world-to-chip interfacing is established. Further, the sample droplets are transported to CE capillary inlet port, separated and detected via a contactless conductivity detector. Working buffers and other solvents needed to perform CE analysis are also delivered as droplets to the DMFP and transported through the CE capillary. The performance of the analyzer is demonstrated by analysis of amino acids in sand matrices. The recovery of the spiked amino acids from the inert sand sample was from 34 to 51% with analysis LOD from 0.2 to 0.6 ppm and migration time RSD from 0.2 to 6.0%. PMID:26426309

  7. Experimental study of the solid-liquid interface in a yield-stress fluid flow upstream of a step

    NASA Astrophysics Data System (ADS)

    Luu, Li-Hua; Pierre, Philippe; Guillaume, Chambon

    2014-11-01

    We present an experimental study where a yield-stress fluid is implemented to carefully examine the interface between a liquid-like unyielded region and a solid-like yielded region. The studied hydrodynamics consists of a rectangular pipe-flow disturbed by the presence of a step. Upstream of the step, a solid-liquid interface between a dead zone and a flow zone appears. This configuration can both model geophysical erosion phenomenon in debris flows or find applications for industrial extrusion processes. We aim to investigate the dominant physical mechanism underlying the formation of the static domain, by combining the rheological characterization of the yield-stress fluid with local measurements of the related hydrodynamic parameters. In this work, we use a model fluid, namely polymer micro-gel Carbopol, that exhibits a Hershel-Bulkley viscoplastic rheology. Exploiting the fluid transparency, the flow is monitored by Particle Image Velocimetry thanks to internal visualization technique. In particular, we demonstrate that the flow above the dead zone roughly behaves as a plug flow whose velocity profile can successfully be described by a Poiseuille equation including a Hershel-Bulkley rheology (PHB theory), with exception of a thin zone at the close vicinity of the static domain. The border inside the flow zone above which the so-called PHB flow starts, is found to be the same regardless of the flow rate and to move with a constant velocity that increases with the flow rate. We interpret this feature as a slip frontier.

  8. Accommodative Behavior of Non-porous Molecular crystal at Solid-Gas and Solid-Liquid Interface

    PubMed Central

    Mande, Hemant M.; Ghalsasi, Prasanna S.

    2015-01-01

    Molecular crystals demonstrate drastically different behavior in solid and liquid state, mainly due to their difference in structural frameworks. Therefore, designing of unique structured molecular compound which can work at both these interfaces has been a challenge. Here, we present remarkable ‘molecular’ property by non-porous molecular solid crystal, dinuclear copper complex (C6H5CH(X)NH2)2CuCl2, to reversibly ‘adsorb’ HCl gas at solid-gas interface as well as ‘accommodate’ azide anion at solid-liquid interface with crystal to crystal transformation. The latter process is driven by molecular recognition, self-assembly, and anchimeric assistance. The observed transformations are feasible due to breathing of inner and outer coordination sphere around metal center resulting in change in metal polyhedra for ‘accommodating’ guest molecule. These transformations cause changes in optical, magnetic, and/or ferroelectric property offering diversity in ‘sensing’ application. With the proposed underlying principles in these exceptional reversible and cyclic transformations, we prepared a series of compounds, can facilitate designing of novel multifunctional molecular materials. PMID:26411980

  9. A Simple Approach to Characterize Gas-Aqueous Liquid Two-phase Flow Configuration Based on Discrete Solid-Liquid Contact Electrification

    PubMed Central

    Choi, Dongwhi; Lee, Donghyeon; Sung Kim, Dong

    2015-01-01

    In this study, we first suggest a simple approach to characterize configuration of gas-aqueous liquid two–phase flow based on discrete solid-liquid contact electrification, which is a newly defined concept as a sequential process of solid-liquid contact and successive detachment of the contact liquid from the solid surface. This approach exhibits several advantages such as simple operation, precise measurement, and cost-effectiveness. By using electric potential that is spontaneously generated by discrete solid–liquid contact electrification, the configurations of the gas-aqueous liquid two-phase flow such as size of a gas slug and flow rate are precisely characterized. According to the experimental and numerical analyses on parameters that affect electric potential, gas slugs have been verified to behave similarly to point electric charges when the measuring point of the electric potential is far enough from the gas slug. In addition, the configuration of the gas-aqueous liquid two-phase microfluidic system with multiple gas slugs is also characterized by using the presented approach. For a proof-of-concept demonstration of using the proposed approach in a self-triggered sensor, a gas slug detector with a counter system is developed to show its practicality and applicability. PMID:26462437

  10. Comparison of the different responses of surface plasmon resonance and quartz crystal microbalance techniques at solid-liquid interfaces under various experimental conditions.

    PubMed

    Fang, Jiajie; Ren, Chunlai; Zhu, Tao; Wang, Kaiyu; Jiang, Zhongying; Ma, Yuqiang

    2015-02-21

    A molecular level understanding of the phenomena taking place at solid-liquid interfaces, ranging from changes in mass to conformation changes, is the key to developing and improving many chemical and biological systems and their scientific and medical applications. Surface plasmon resonance (SPR) and quartz crystal microbalance (QCM) techniques are often coupled to achieve this understanding. We divided various experimentally relevant scenarios into the following six categories: boundary solutions; surface modifications; conformation; viscoelastic properties; molecular ruler; and mass sensitivity. For each case, based on theoretical analyses, we discuss the following four points with respect to discrete adsorbates at solid-liquid interfaces: (1) the different types of information that can be obtained, why it can be obtained and how to obtain it; (2) the origins of many current approaches and why they are imperfect; (3) guidelines for experimental design; and (4) possible studies, such as the effect of dimensional confinement and adsorption forces on the ability of conformational changes to occur on the receipt of external stimuli and the hysteresis in these changes. PMID:25575354

  11. Double multiple-relaxation-time lattice Boltzmann model for solid-liquid phase change with natural convection in porous media

    NASA Astrophysics Data System (ADS)

    Liu, Qing; He, Ya-Ling

    2015-11-01

    In this paper, a double multiple-relaxation-time lattice Boltzmann model is developed for simulating transient solid-liquid phase change problems in porous media at the representative elementary volume scale. The model uses two different multiple-relaxation-time lattice Boltzmann equations, one for the flow field and the other for the temperature field with nonlinear latent heat source term. The model is based on the generalized non-Darcy formulation, and the solid-liquid interface is traced through the liquid fraction which is determined by the enthalpy-based method. The present model is validated by numerical simulations of conduction melting in a semi-infinite space, solidification in a semi-infinite corner, and convection melting in a square cavity filled with porous media. The numerical results demonstrate the efficiency and accuracy of the present model for simulating transient solid-liquid phase change problems in porous media.

  12. New Composite Membranes for High Throughput Solid-Liquid Separations at the Savannah River Site

    SciTech Connect

    Bhave, Ramesh R

    2012-01-01

    New Composite Membranes for High Throughput Solid-Liquid Separations at the Savannah River Site R. Bhave (Oak Ridge National Laboratory. Oak Ridge, TN) and M. R. Poirier* (Savannah River National Laboratory, Aiken SC) Solid-liquid separation is the limiting step for many waste treatment processes at the Savannah River Site. SRNL researchers have identified the rotary microfilter as a technology to improve the rate of solid-liquid separation processes. SRNL is currently developing the rotary microfilter for radioactive service and plans to deploy the technology as part of the small column ion exchange process. The rotary microfilter can utilize any filter media that is available as a flat sheet. The current baseline membrane is a 0.5 micron (nominal) porous metal filter (Pall PMM050). Previous testing with tubular filters showed that filters composed of a ceramic membrane on top of a stainless steel support produce higher flux than filters composed only of porous metal. The authors are working to develop flat sheet filter media composed of a ceramic membrane and/or ceramic-metal composite on top of a porous stainless steel support that can be used with the rotary microfilter to substantially increase filter flux resulting in a more compact, energy efficient and cost-effective high level radioactive waste treatment system. Composite membranes with precisely controlled pore size distribution were fabricated on porous metal supports. High quality uniform porous metal (316SS) supports were fabricated to achieve high water permeability. Separative layers of several different materials such as ultrafine metal particles and ceramic oxides were used to fabricate composite membranes. The fabrication process involved several high temperature heat treatments followed by characterization of gas and liquid permeability measurements and membrane integrity analysis. The fabricated composite membrane samples were evaluated in a static test cell manufactured by SpinTek. The

  13. Coarsening in Solid-Liquid Mixtures Studied on the Space Shuttle

    NASA Technical Reports Server (NTRS)

    Caruso, John J.

    1999-01-01

    Ostwald ripening, or coarsening, is a process in which large particles in a two-phase mixture grow at the expense of small particles. It is a ubiquitous natural phenomena occurring in the late stages of virtually all phase separation processes. In addition, a large number of commercially important alloys undergo coarsening because they are composed of particles embedded in a matrix. Many of them, such as high-temperature superalloys used for turbine blade materials and low-temperature aluminum alloys, coarsen in the solid state. In addition, many alloys, such as the tungsten-heavy metal systems, coarsen in the solid-liquid state during liquid phase sintering. Numerous theories have been proposed that predict the rate at which the coarsening process occurs and the shape of the particle size distribution. Unfortunately, these theories have never been tested using a system that satisfies all the assumptions of the theory. In an effort to test these theories, NASA studied the coarsening process in a solid-liquid mixture composed of solid tin particles in a liquid lead-tin matrix. On Earth, the solid tin particles float to the surface of the sample, like ice in water. In contrast, in a microgravity environment this does not occur. The microstructures in the ground- and space-processed samples (see the photos) show clearly the effects of gravity on the coarsening process. The STS-83-processed sample (right image) shows nearly spherical uniformly dispersed solid tin particles. In contrast, the identically processed, ground-based sample (left image) shows significant density-driven, nonspherical particles, and because of the higher effective solid volume fraction, a larger particle size after the same coarsening time. The "Coarsening in Solid-Liquid Mixtures" (CSLM) experiment was conducted in the Middeck Glovebox facility (MGBX) flown aboard the shuttle in the Microgravity Science Laboratory (MSL-1/1R) on STS-83/94. The primary objective of CSLM is to measure the temporal

  14. Numerical Calculation of the Morphology of a Solid/Liquid Interface Near an Insoluble Particle

    NASA Technical Reports Server (NTRS)

    Catalina, Adrian V.; Stefanescu, Doru M.; Sen, Subhayu

    2003-01-01

    A numerical mathematical model capable of accurately describing the evolution of the shape of the solid/liquid interface in the proximity of a foreign particle is presented in this paper. The model accounts for the influence of the temperature gradient and the Gibbs-Thomson and disjoining pressure effects. It shows that for the systems characterized by k(sub P) < k(sub L) the disjoining pressure causes the interface curvature to change its sign in the close-contact particle/interface region. It also shows that the increase of the temperature gradient diminishes the effect of the disjoining pressure. Calculated critical solidification velocities for the pushing/engulfment transition are compared with experimental measurements performed in microgravity conditions.

  15. Measurement of solid liquid interfacial energy in the pyrene succinonitrile monotectic system

    NASA Astrophysics Data System (ADS)

    Akbulut, S.; Ocak, Y.; Böyük, U.; Erol, M.; Keslioglu, K.; Marasli, N.

    2006-09-01

    The equilibrated grain boundary groove shapes for solid pyrene (PY) in equilibrium with the PY succinonitrile (SCN) monotectic liquid were directly observed. From the observed grain boundary groove shapes, the Gibbs-Thomson coefficient and solid-liquid interfacial energy for solid PY in equilibrium with the PY SCN monotectic liquid have been determined to be (8.72 ± 0.87) × 10-8 K m and (21.9 ± 3.28) × 10-3 J m-2 with the present numerical method and Gibbs-Thomson equation, respectively. The grain boundary energy of the solid PY phase has been determined to be (42.84 ± 7.28) × 10-3 J m-2 from the observed grain boundary groove shapes. Thermal conductivities of solid and liquid phases for PY-2.5 mol% SCN alloy and pure PY have also been measured.

  16. New density functional approach for solid-liquid-vapor transitions in pure materials.

    PubMed

    Kocher, Gabriel; Provatas, Nikolas

    2015-04-17

    A new phase field crystal (PFC) type theory is presented, which accounts for the full spectrum of solid-liquid-vapor phase transitions within the framework of a single density order parameter. Its equilibrium properties show the most quantitative features to date in PFC modeling of pure substances, and full consistency with thermodynamics in pressure-volume-temperature space is demonstrated. A method to control either the volume or the pressure of the system is also introduced. Nonequilibrium simulations show that 2- and 3-phase growth of solid, vapor, and liquid can be achieved, while our formalism also allows for a full range of pressure-induced transformations. This model opens up a new window for the study of pressure driven interactions of condensed phases with vapor, an experimentally relevant paradigm previously missing from phase field crystal theories. PMID:25933321

  17. Effects of Solid-Liquid Mixing on Microstructure of Semi-Solid A356 Aluminum Alloy

    NASA Astrophysics Data System (ADS)

    Guo, H. M.; Wang, L. J.; Wang, Q.; Yang, X. J.

    2014-08-01

    The desired starting material for semi-solid processing is the semi-solid slurry in which the solid phase is present as fine and globular particles. A modified solid-liquid mixing (SLM) is reported wherein semi-solid slurry can be produced by mixing a solid alloy block into a liquid alloy, and mechanical vibration is utilized to enhance the mixing. Effects such as liquid alloy temperature, mass ratio, and mixing intensity on the microstructure and the cooling curves during SLM were evaluated. 2D and 3D microstructure analysis of treated A356 aluminum alloy shows that microstructure can be refined significantly with a considerable morphology change in primary Al phase. It is critical that the temperature of mixture after mixing is lower than its liquidus temperature to obtain a valid SLM process. Specially, mixing intensity is identified as a primary factor for a favorable microstructure of semi-solid slurry.

  18. Surface Specularity as an Indicator of Shock-induced Solid-liquid Phase Transitions in Tin

    SciTech Connect

    G. D. Stevens, S. S. Lutz, B. R. Marshall, W.D. Turley, et al.

    2007-12-01

    When highly polished metal surfaces melt upon release after shock loading, they exhibit features that suggest significant surface changes accompany the phase transition. The reflection of light from such surfaces changes from specular (pre-shock) to diffuse upon melting. Typical of this phenomenon is the loss of signal light in velocity interferometer system for any reflector (VISAR) measurements, which usually occurs at pressures high enough to melt the free surface. Unlike many other potential material phase-sensitive diagnostics (e.g., reflectometry, conductivity), that show relatively small (1%-10%) changes, the specularity of reflection provides a more sensitive and definitive (>10x) indication of the solid-liquid phase transition. Data will be presented that support the hypothesis that specularity changes indicate melt in a way that can be measured easily and unambiguously.

  19. New Density Functional Approach for Solid-Liquid-Vapor Transitions in Pure Materials

    NASA Astrophysics Data System (ADS)

    Kocher, Gabriel; Provatas, Nikolas

    2015-04-01

    A new phase field crystal (PFC) type theory is presented, which accounts for the full spectrum of solid-liquid-vapor phase transitions within the framework of a single density order parameter. Its equilibrium properties show the most quantitative features to date in PFC modeling of pure substances, and full consistency with thermodynamics in pressure-volume-temperature space is demonstrated. A method to control either the volume or the pressure of the system is also introduced. Nonequilibrium simulations show that 2- and 3-phase growth of solid, vapor, and liquid can be achieved, while our formalism also allows for a full range of pressure-induced transformations. This model opens up a new window for the study of pressure driven interactions of condensed phases with vapor, an experimentally relevant paradigm previously missing from phase field crystal theories.

  20. Modeling of ultrasound transmission through a solid-liquid interface comprising a network of gas pockets

    NASA Astrophysics Data System (ADS)

    Paumel, K.; Moysan, J.; Chatain, D.; Corneloup, G.; Baqué, F.

    2011-08-01

    Ultrasonic inspection of sodium-cooled fast reactor requires a good acoustic coupling between the transducer and the liquid sodium. Ultrasonic transmission through a solid surface in contact with liquid sodium can be complex due to the presence of microscopic gas pockets entrapped by the surface roughness. Experiments are run using substrates with controlled roughness consisting of a network of holes and a modeling approach is then developed. In this model, a gas pocket stiffness at a partially solid-liquid interface is defined. This stiffness is then used to calculate the transmission coefficient of ultrasound at the entire interface. The gas pocket stiffness has a static, as well as an inertial component, which depends on the ultrasonic frequency and the radiative mass.

  1. Anaerobic digestion of acidified slurry fractions derived from different solid-liquid separation methods.

    PubMed

    Sutaryo, Sutaryo; Ward, Alastair James; Møller, Henrik Bjarne

    2013-02-01

    Batch assays investigating the ultimate methane yields (B(0)) of acidified slurry fractions produced with different solid-liquid slurry separation techniques were done. The result showed that the anaerobic digestion (AD) process was inhibited when raw and liquid fractions of sow, pig and dairy cow acidified slurry are digested, but AD treating solid fractions (SF) acidified slurry showed no sulphide inhibition. The B(0) of SF acidified sow slurry increased significantly with increasing screen size in the screw press. No significant effect of acidification processes on B(0) of SF dairy cow slurry (DCS) was observed. The ultimate methane yields of SF acidified DCS and SF non acidified DCS were 278±13 and 289±1LkgVS(-1), while in term of fresh weigh substrate were 59±2.8 and 59±0.3Lkgsubstrate(-1), respectively. PMID:23313767

  2. Local conformational switching of supramolecular networks at the solid/liquid interface.

    PubMed

    Cometto, Fernando P; Kern, Klaus; Lingenfelder, Magalí

    2015-05-26

    We use the electric field in a scanning tunneling microscope to manipulate the transition between open and close packed 2D supramolecular networks of neutral molecules in nonpolar media. We found that while the magnitude of the applied field is not decisive, it is the sign of the polarization that needs to be maintained to select one particular polymorph. Moreover, the switching is independent of the solvent used and fully reversible. We propose that the orientation of the surface dipole determined by the electric field might favor different conformation-depended charge transfer mechanisms of the adsorbates to the surface, inducing open (closed) structures for negative (positive) potentials. Our results show the use of local fields to select the polymorphic outcome of supramolecular assemblies at the solid/liquid interface. The effect has potential to locally control the capture and release of analytes in host-guest systems and the 2D morphology in multicomponent layers. PMID:25857528

  3. Influence of solid-liquid separation strategy on biogas yield from a stratified swine production system.

    PubMed

    Cestonaro do Amaral, André; Kunz, Airton; Radis Steinmetz, Ricardo Luis; Scussiato, Lucas Antunes; Tápparo, Deisi Cristina; Gaspareto, Taís Carla

    2016-03-01

    As the fourth largest swine producer and exporter, Brazil has increased its participation in the global swine production market. Generally, these units concentrate a large number of animals and generate effluents that must be correctly managed to prevent environmental impacts, being anaerobic digestion is an interesting alternative for treating these effluents. The low-volatile solid concentration in the manure suggests the need for solid-liquid separation as a tool to improve the biogas generation capacity. This study aimed to determine the influence of simplified and inexpensive solid-liquid separation strategies (screening and settling) and the different manures produced during each swine production phase (gestating and farrowing sow houses, nursery houses and finishing houses) on biogas and methane yield. We collected samples in two gestating sow houses (GSH-a and GSH-b), two farrowing sow houses (FSH-a and FSH-b), a nursery house (NH) and a finishing house (FH). Biochemical methane potential (BMP) tests were performed according to international standard procedures. The settled sludge fraction comprised 20-30% of the raw manure volume, which comprises 40-60% of the total methane yield. The methane potential of the settled sludge fraction was approximately two times higher than the methane potential of the supernatant fraction. The biogas yield differed among the raw manures from different swine production phases (GSH-a 326.4 and GSH-b 577.1; FSH-a 860.1 and FSH-b 479.2; NH -970.2; FH 474.5 NmLbiogas.gVS(-1)). The differences were relative to the production phase (feed type and feeding techniques) and the management of the effluent inside the facilities (water management). Brazilian swine production has increased his participation in the global market, been the fourth producer and the fourth exporter. The segregation of swine production in multiple sites has increased its importance, due to the possibilities to have more specialized units. Generally, these units

  4. Ginzburg-Landau theory for the solid-liquid interface of bcc elements

    NASA Technical Reports Server (NTRS)

    Shih, W. H.; Wang, Z. Q.; Zeng, X. C.; Stroud, D.

    1987-01-01

    Consideration is given to a simple order-parameter theory for the interfacial tension of body-centered-cubic solids in which the principal order parameter is the amplitude of the density wave at the smallest nonzero reciprocal-lattice vector of the solid. The parameters included in the theory are fitted to the measured heat of fusion, melting temperature, and solid-liquid density difference, and to the liquid structure factor and its temperature derivative at freezing. Good agreement is found with experiment for Na and Fe and the calculated anisotropy of the surface tension among different crystal faces is of the order of 2 percent. On the basis of various assumptions about the universal behavior of bcc crystals at melting, the formalism predicts that the surface tension is proportional to the heat of fusion per surface atom.

  5. Preparation of a smooth GaN-Gallium solid-liquid interface

    NASA Astrophysics Data System (ADS)

    de Jong, A. E. F.; Vonk, V.; Ruat, M.; Boćkowski, M.; Kamler, G.; Grzegory, I.; Honkimäki, V.; Vlieg, E.

    2016-08-01

    We discuss the preparation of an atomically flat solid-liquid interface between solid gallium nitride and liquid gallium using in situ surface X-ray diffraction to probe the interface roughness. For the creation of this interface it is necessary to start the experiment with liquid gallium which first etches into the solid at a temperature of 823 K in a nitrogen free ambient. After this rigorous cleaning procedure there is perfect wetting between solid and liquid. The roughness created due to the fast etching of the solid has to be repaired at a nitrogen pressure of 10-20 bar and a temperature around 1150 K. The (2,1) crystal truncation rod data are excellently described by a surface model having 0±0.1 Å roughness, which indicates a successful repair. The lateral length scale on which the roughness is determined has a lower limit of 750±50 Å.

  6. Modeling of ultrasound transmission through a solid-liquid interface comprising a network of gas pockets

    SciTech Connect

    Paumel, K.; Baque, F.; Moysan, J.; Corneloup, G.; Chatain, D.

    2011-08-15

    Ultrasonic inspection of sodium-cooled fast reactor requires a good acoustic coupling between the transducer and the liquid sodium. Ultrasonic transmission through a solid surface in contact with liquid sodium can be complex due to the presence of microscopic gas pockets entrapped by the surface roughness. Experiments are run using substrates with controlled roughness consisting of a network of holes and a modeling approach is then developed. In this model, a gas pocket stiffness at a partially solid-liquid interface is defined. This stiffness is then used to calculate the transmission coefficient of ultrasound at the entire interface. The gas pocket stiffness has a static, as well as an inertial component, which depends on the ultrasonic frequency and the radiative mass.

  7. Design of a monochromatic ellipsometer for studies at the solid-liquid interface

    NASA Astrophysics Data System (ADS)

    Pai-Panandiker, R. S.; Dorgan, J. R.

    1995-02-01

    A new design for a monochromatic ellipsometer used for studies at the solid-liquid interface is described. The design of the ellipsometer incorporates two novel features—a special optical glass cell and a thermally controlled sample oven. The ellipsometer design allows for in situ kinetic studies through use of the optical glass cell. Furthermore, the apparatus is modified to allow thermal equilibration over a range of temperatures. The temperature response of the cell assembly is presented and the response time is seen to be approximately 1 h. Data on the adsorption of a diblock copolymer [poly(ethylene oxide)-block-polystyrene] are presented; the analyzed data agree with previous studies on the same system.

  8. Solid/liquid phase diagram of the ammonium sulfate/succinic acid/water system.

    PubMed

    Pearson, Christian S; Beyer, Keith D

    2015-05-14

    We have studied the low-temperature phase diagram and water activities of the ammonium sulfate/succinic acid/water system using differential scanning calorimetry and infrared spectroscopy of thin films. Using the results from our experiments, we have mapped the solid/liquid ternary phase diagram, determined the water activities based on the freezing point depression, and determined the ice/succinic acid phase boundary as well as the ternary eutectic composition and temperature. We also compared our results to the predictions of the extended AIM aerosol thermodynamics model (E-AIM) and found good agreement for the ice melting points in the ice primary phase field of this system; however, differences were found with respect to succinic acid solubility temperatures. We also compared the results of this study with those of previous studies that we have published on ammonium sulfate/dicarboxylic acid/water systems. PMID:25431860

  9. SOLIEX: A Novel Solid-Liquid Method of Radionuclides Extraction from Radioactive Waste Solutions - 13486

    SciTech Connect

    Shilova, E.; Viel, P.; Huc, V.

    2013-07-01

    This paper describes recent developments in new solid-liquid extraction method, called SOLIEX, to remove cesium from alkaline solutions. SOLIEX relies on the use of a reversible complexing system comprising a carbon felt bearing molecular traps (calixarenes). This complexing system exhibits a high selectivity for Cs, and is thus expected to be helpful for the treatment of highly diluted cesium wastes even with a high concentration of competing alkali metal cations. As additional advantage, this complexing system can be adapted by molecular engineering to capture other radionuclides, such as Sr, Eu, Am. Finally, this complexing system can be easily and efficiently regenerated by using a cost effective stripping procedure, which limits further generation of waste to meet 'zero liquid' discharge requirements for nuclear facilities. (authors)

  10. Force response of actively deformed polymer microdroplets: dependence on the solid/liquid boundary condition

    NASA Astrophysics Data System (ADS)

    Heppe, Jonas; McGraw, Joshua D.; Bennewitz, Roland; Jacobs, Karin

    2015-03-01

    In fluid dynamics, the solid/liquid boundary condition can play a major role in the flow behavior of a liquid. For example, in the dewetting of identical polymer films on weak slip or strong slip substrates, large qualitative and quantitative differences are observed. Therefore, when applying an external load to a liquid resting on such substrates, the measured reaction forces and the ensuing flow should also depend on the boundary condition. We present atomic force microscopy measurements in which the reaction force of a cantilever is measured as the tip pierces liquid polymer micron sized droplets and films. These indentations are done on substrates with tuned slip. Accessing the size, depth and rate dependence of the resulting force distance curves, we show an influence of the slip condition on the dissipated energy and adhesion.

  11. Design and Testing of a Solid-Liquid Interface Monitor for High-Level Waste Tanks

    SciTech Connect

    McDaniel, D.; Awwad, A.; Roelant, D.; Srivastava, R.

    2008-07-01

    A high-level waste (HLW) monitor has been designed, fabricated and tested at full-scale for deployment inside a Hanford tank. The Solid-Liquid Interface Monitor (SLIM) integrates a commercial sonar system with a mechanical deployment system for deploying into an underground waste tank. The system has undergone several design modifications based upon changing requirements at Hanford. We will present the various designs of the monitor from first to last and will present performance data from the various prototype systems. We will also present modeling of stresses in the enclosure under 85 mph wind loading. The system must be able to function at winds up to 15 mph and must withstand a maximum loading of 85 mph. There will be several examples presented of engineering tradeoffs made as FIU analyzed new requirements and modified the design to accommodate. We will present our current plans for installing into the Cold Test Facility at Hanford and into a double-shelled tank at Hanford. Finally, we will present our vision for how this technology can be used at Hanford and Savannah River Site to improve the filling and emptying of high-level waste tanks. In conclusion: 1. The manually operated first-generation SLIM is a viable option on tanks where personnel are allowed to work on top of the tank. 2. The remote controlled second-generation SLIM can be utilized on tanks where personnel access is limited. 3. The totally enclosed fourth-generation SLIM, when the design is finalized, can be used when the possibility exists for wind dispersion of any HLW that maybe on the system. 4. The profiling sonar can be used effectively for real-time monitoring of the solid-liquid interface over a large area. (authors)

  12. First-principles molecular dynamics simulations at solid-liquid interfaces with a continuum solvent.

    PubMed

    Sánchez, Verónica M; Sued, Mariela; Scherlis, Damián A

    2009-11-01

    Continuum solvent models have become a standard technique in the context of electronic structure calculations, yet no implementations have been reported capable to perform molecular dynamics at solid-liquid interfaces. We propose here such a continuum approach in a density functional theory framework using plane-wave basis sets and periodic boundary conditions. Our work stems from a recent model designed for Car-Parrinello simulations of quantum solutes in a dielectric medium [D. A. Scherlis et al., J. Chem. Phys. 124, 074103 (2006)], for which the permittivity of the solvent is defined as a function of the electronic density of the solute. This strategy turns out to be inadequate for systems extended in two dimensions: the dependence of the dielectric function on the electronic density introduces a new term in the Kohn-Sham potential, which becomes unphysically large at the interfacial region, seriously affecting the convergence of the self-consistent calculations. If the dielectric medium is properly redefined as a function of the atomic coordinates, a good convergence is obtained and the constant of motion is conserved during the molecular dynamics simulations. The Poisson problem is solved using a multigrid method, and in this way Car-Parrinello molecular dynamics simulations of solid-liquid interfaces can be performed at a very moderate computational cost. This scheme is employed to investigate the acid-base equilibrium at the TiO(2)-water interface. The aqueous behavior of titania surfaces has stimulated a large amount of experimental research, but many open questions remain concerning the molecular mechanisms determining the chemistry of the interface. Here we make an attempt to answer some of them, putting to the test our continuum model. PMID:19894999

  13. Adsorption/aggregation of surfactants and their mixtures at solid-liquid interfaces.

    PubMed

    Somasundaran, P; Huang, L

    2000-12-11

    Adsorption of surfactants and polymers at solid-liquid interfaces is used widely to modify interfacial properties in a variety of industrial processes such as flotation, ceramic processing, flocculation/dispersion, personal care product formulation and enhanced oil recovery. The behavior of surfactants and polymers at interfaces is determined by a number of forces, including electrostatic attraction, covalent bonding, hydrogen bonding, hydrophobic bonding, and solvation and desolvation of various species. The extent and type of the forces involved varies depending on the adsorbate and the adsorbent, and also the composition and other characteristics of the solvent and dissolved components in it. The influence of such forces on the adsorption behavior is reviewed here from a thermodynamics point of view. The experimental results from microcalorimetric and spectroscopic studies of adsorbed layers of different surfactant and polymer systems at solid-liquid interfaces are also presented. Calorimetric data from the adsorption of an anionic surfactant, sodium octylbenzenesulfonate, and a non-ionic surfactant, dodecyloxyheptaethoxyethylalcohol, and their mixtures on alumina, yielded important thermodynamic information. It was found that the adsorption of anionic surfactants alone on alumina was initially highly exothermic due to the electrostatic interaction with the substrate. Further adsorption leading to a solloid (hemimicelle) formation is proposed to be mainly an entropy-driven process. The entropy effect was found to be more pronounced for the adsorption of anionic-non-ionic surfactant mixtures than for the anionic surfactant alone. Fluorescence studies using a pyrene probe on an adsorbed surfactant and polymer layers, along with electron spin resonance (ESR) spectroscopy, reveal the role of surface aggregation and the conformation of the adsorbed molecules in controlling the dispersion and wettability of the system. PMID:11185696

  14. Modélisation du cycle de vie d'un polluant en atmosphère : application aux oxydes d'azote (NO{X})

    NASA Astrophysics Data System (ADS)

    Hamzi, R.; Bourmada, N.; Benamrane, B. T.; Londiche, H.

    2005-05-01

    Les problèmes de l'environnement nécessitent des modélisations particulièrement difficiles, mais d'une grande importance sociale. C'est un domaine récent, où les données sont encore peu nombreuses, mais où les attentes sont considérables, tant auprès du public que des politiques et des industriels. En effet, la modélisation consiste à définir un modèle qui permettra de représenter efficacement le processus étudié. Dans cette optique le comportement modélisé n'est que la manifestation extérieure d'une structure plus profonde. La complexité du système et du problème posé détermine celle du modèle, qui va de la simple représentation qualitative d'un comportement aux formules mathématiques les plus élaborées. Lorsque la modélisation est exprimée mathématiquement, on recourt généralement à un programme de simulation pour calculer le comportement prévisionnel du modèle. La compréhension du cycle de vie d'un polluant en atmosphère, dans notre cas les oxydes d'azote (NOX), nécessite la modélisation de l'évolution des réactifs et des produits en fonction du temps exprimée par des équations différentielles. La réalisation de la simulation à partir de ces modèles, nous permet de connaître l'ensemble des processus ayant lieu lors de l'émission du polluant en atmosphère jusqu'à sa consommation.

  15. Laboratory Production of Lemon Liqueur (Limoncello) by Conventional Maceration and a Two-Syringe System to Illustrate Rapid Solid-Liquid Dynamic Extraction

    ERIC Educational Resources Information Center

    Naviglio, Daniele; Montesano, Domenico; Gallo, Monica

    2015-01-01

    Two experimental techniques of solid-liquid extraction are compared relating to the lab-scale production of lemon liqueur, most commonly named "limoncello"; the first is the official method of maceration for the solid-liquid extraction of analytes and is widely used to extract active ingredients from a great variety of natural products;…

  16. Manifestations de la transition solide-liquide dans les agrégats

    NASA Astrophysics Data System (ADS)

    Calvo, F.

    The thermodynamics of clusters is a subject of increasing interest, both from the theoretical and experimental points of view. We present a set of theoretical and numerical methods for studying phase transitions, especially the solid-liquid transition, in atomic or molecular clusters. Several means of characterization (thermodynamical, geometrical and dynamical) are introduced, and the differences between the finite-size behaviour and the bulk behaviour are described. The phenomenon of "dynamical coexistence", which can be seen as the cluster spontaneously going back and forth between the solid and liquid states across the time, is illustrated. Its thermodynamical consequences are also emphasized. Finally, we present some typical thermodynamical phenomena due to the finite-size character, and strongly dependent on the physical chemistry of the matter at the microscopic level. We study these phenomena with Monte Carlo and molecular dynamics simulations: surface melting observed on rare gas clusters, multistage melting observed on ionic clusters, the special behaviours of molecular clusters, and the more intricate problem of free or solvated metallic clusters. La thermodynamique des agrégats est un sujet en développement croissant, tant sur le plan théorique qu'expérimental. Nous présentons un ensemble de méthodes théoriques et numériques destinées à l'étude des transitions de phase, en particulier de la transition solide-liquide, dans les agrégats atomiques et moléculaires. Divers moyens de caractérisation (thermodynamiques, géométriques et dynamiques) sont introduits, et les différences entre les comportements à taille finie et à taille macroscopique sont précisées. Le phénomène de "coexistence dynamique", qui voit l'agrégat passer spontanément de l'état solide à l'état liquide (et réciproquement) au cours du temps, est illustré, et ses conséquences thermodynamiques sont soulignées. Enfin, nous présentons un certain nombre de ph

  17. Solid-liquid separation of oxidized americium from fission product lanthanides

    NASA Astrophysics Data System (ADS)

    Shehee, T. C.; Martin, L. R.; Nash, K. L.

    2010-03-01

    The separation of americium from the lanthanides and curium is a requirement if transmutation of americium is to be performed in advanced nuclear fuel cycles. Oxidation of Am3+ to AmO2+ or AmO22+ may allow separation of Am from Ln and Cm in one step, since the lanthanides and curium do not have higher oxidation states as accessible. Two possible solid-liquid separation methods have been developed to address this difficult separation. Under acidic conditions using oxone or persulfate, the oxidation and retention of tracer Am in the aqueous phase has been observed with a separation factor of 11 ± 1. Most of these studies have been conducted using 237NpO2(NO3), 233UO2(NO3)2, 238Pu(NO3)4 and 241Am(NO3)3 at radiotracer concentrations. Lanthanides precipitate as the sodium or potassium europium double sulfate salt. Under basic conditions, ozone oxidation of Am(CO3)OH(s) solubilizes Am from a lanthanide carbonate hydroxide solid phase to the aqueous phase as the AmO2(CO3)34-or AmO2(CO3)35- species. For the ozone oxidation of the americium tracer a separation factor of 1.6 ± 0.8 and 47 ± 2 for the oxidation/separation in Na2CO3 and NaHCO3 respectively.

  18. The impact of algal properties and pre-oxidation on solid-liquid separation of algae.

    PubMed

    Henderson, Rita; Parsons, Simon A; Jefferson, Bruce

    2008-04-01

    Algae are traditionally classified according to biological descriptors which do not give information on surface characteristics that are important with respect to removal by water treatment processes. This review examines the character of freshwater algal populations from a water treatment perspective and evaluates the impact of their varying properties and the use of pre-oxidation on their removal by solid-liquid separation processes.. The characteristics shown to impact on treatment were morphology, motility, surface charge, cell density and the extracellular organic matter (EOM) composition and concentration. With the exception of density, these are not phyla specific. It was also shown that dissolved air flotation (DAF) was the most robust clarification method, where up to 99.8% removal was achieved compared to 94% for sedimentation when using metal coagulants. However, successful clarification relied heavily on the optimisation of preceding coagulation and flocculation and coagulant demand was important in this respect. Comparison of all available data reveals a relationship between cell surface area and coagulant demand. It is thus suggested that cell surface area would provide a basis for regrouping algae such that the classification is informative with respect to water treatment. However, the absolute coagulant demand is a result of both surface area and EOM influences. The latter are relatively poorly understood in comparison to natural organic matter (NOM) systems and this remains a limit in current knowledge. PMID:18261761

  19. Measurements of Solid-Liquid Interfacial Energies in the Organic Monotectic Alloys

    NASA Astrophysics Data System (ADS)

    Böyük, U.; Yüceer, K.; Keşlioğlu, K.; Ulgen, A.; Maraşli, N.

    The commercial purity dibromobenzene (DBB) and succinonitrile (SCN) were purified using a columnar distillation system. Thin walled rectangular specimen cells (60-80 μm thick) were fabricated and filled with the purified materials under the vacuum. The specimen cell was placed in a horizontal temperature gradient stage. A thin liquid layer was melted and the specimen was annealed in a constant temperature gradient for an enough time to observe the equilibrated grain boundary groove shapes. The thermal conductivities of solid and liquid phases for the purified DBB and DBB-5.7 mol% SCN alloy were determined with the radial heat flow and the Bridgman-type growth apparatuses. From the observed grain boundary groove shapes, the Gibbs-Thomson coefficients, solid-liquid interfacial energies, and the grain boundary energies for solid DBB in equilibrium with its melts and solid DBB in equilibrium with DBB-SCN monotectic liquid have been determined. The temperature coefficients of the purified DBB and DBB-5.7 mol% SCN alloy were also determined from thermal conductivity curve vs temperature.

  20. Measurement of solid-liquid interfacial energy in the pyrene succinonitrile monotectic system.

    PubMed

    Akbulut, S; Ocak, Y; Böyük, U; Erol, M; Keşlioğlu, K; Maraşli, N

    2006-09-20

    The equilibrated grain boundary groove shapes for solid pyrene (PY) in equilibrium with the PY succinonitrile (SCN) monotectic liquid were directly observed. From the observed grain boundary groove shapes, the Gibbs-Thomson coefficient and solid-liquid interfacial energy for solid PY in equilibrium with the PY SCN monotectic liquid have been determined to be (8.72 ± 0.87) × 10(-8) K m and (21.9 ± 3.28) × 10(-3) J m(-2) with the present numerical method and Gibbs-Thomson equation, respectively. The grain boundary energy of the solid PY phase has been determined to be (42.84 ± 7.28) × 10(-3) J m(-2) from the observed grain boundary groove shapes. Thermal conductivities of solid and liquid phases for PY-2.5 mol% SCN alloy and pure PY have also been measured. PMID:21690896

  1. Coarsening in Solid-Liquid Mixtures-2: A Materials Science Experiment for the ISS

    NASA Technical Reports Server (NTRS)

    Hickman, J. Mark; Voorhees, Peter W.; Kwon, Yongwoo; Lorik, Tibor

    2004-01-01

    A materials science experiment has been developed and readied for operation aboard the International Space Station (ISS). Components of this experiment are onboard ISS and area awaiting the flight of science samples. The goal of the experiment is to understand the dynamics of Ostwald ripening, also known as coarsening, a process that occurs in nearly any two-phase mixture found in nature. Attempts to obtain experimental data in ground-based laboratories are hindered due to the presence of gravity, which introduces material transport modes other than that of the coarsening phenomenon. This introduces adjustable parameters in the formulation of theory. The original Coarsening in Solid-Liquid Mixtures (CSLM) mission, which flew on the Space Shuttle in 1997, produced data from a coarsened eutectic alloy. Unfortunately, both the science matrix and the hardware, while nominally functional, did not account adequately for operations in microgravity. A significantly redesigned follow-on experiment, CSLM-2 has been developed to redress the inadequacies of the original experiment. This paper reviews the CSLM-2 project: its history, science goals, flight hardware implementation, and planned operations and analysis

  2. Biodegradation of Endocrine Disruptors in Solid-Liquid Two-Phase Partitioning Systems by Enrichment Cultures

    PubMed Central

    dos Santos, Silvia Cristina Cunha; Ouellette, Julianne; Juteau, Pierre; Lépine, François; Déziel, Eric

    2013-01-01

    Naturally occurring and synthetic estrogens and other molecules from industrial sources strongly contribute to the endocrine disruption of urban wastewater. Because of the presence of these molecules in low but effective concentrations in wastewaters, these endocrine disruptors (EDs) are only partially removed after most wastewater treatments, reflecting the presence of these molecules in rivers in urban areas. The development of a two-phase partitioning bioreactor (TPPB) might be an effective strategy for the removal of EDs from wastewater plant effluents. Here, we describe the establishment of three ED-degrading microbial enrichment cultures adapted to a solid-liquid two-phase partitioning system using Hytrel as the immiscible water phase and loaded with estrone, estradiol, estriol, ethynylestradiol, nonylphenol, and bisphenol A. All molecules except ethynylestradiol were degraded in the enrichment cultures. The bacterial composition of the three enrichment cultures was determined using 16S rRNA gene sequencing and showed sequences affiliated with bacteria associated with the degradation of these compounds, such as Sphingomonadales. One Rhodococcus isolate capable of degrading estrone, estradiol, and estriol was isolated from one enrichment culture. These results highlight the great potential for the development of TPPB for the degradation of highly diluted EDs in water effluents. PMID:23728808

  3. Unified phonon-based approach to the thermodynamics of solid, liquid and gas states

    NASA Astrophysics Data System (ADS)

    Bolmatov, Dima; Zav'yalov, Dmitry; Zhernenkov, Mikhail; Musaev, Edvard T.; Cai, Yong Q.

    2015-12-01

    We introduce a unified approach to states of matter (solid, liquid and gas) and describe the thermodynamics of the pressure-temperature phase diagram in terms of phonon excitations. We derive the effective Hamiltonian with low-energy cutoff in two transverse phonon polarizations (phononic band gaps) by breaking the symmetry in phonon interactions. Further, we construct the statistical mechanics of states of aggregation employing the Debye approximation. The introduced formalism covers the Debye theory of solids, the phonon theory of liquids, and thermodynamic limits such as the Dulong-Petit thermodynamic limit (cV = 3kB), the ideal gas limit (cV =3/2 kB) and the new thermodynamic limit (cV = 2kB), dubbed here the Frenkel line thermodynamic limit. We discuss the phonon propagation and localization effects in liquids above and below the Frenkel line, and explain the "fast sound" phenomenon. As a test for our theory we calculate velocity-velocity autocorrelation and pair distribution functions within the Green-Kubo formalism. We show the consistency between dynamics of phonons and pair correlations in the framework of the unified approach. New directions towards advancements in phononic band gaps engineering, hypersound manipulation technologies and exploration of exotic behaviour of fluids relevant to geo- and planetary sciences are discussed. The presented results are equally important both for practical implications and for fundamental research.

  4. Focused ultrasound solid-liquid extraction for the determination of organic biomarkers in beachrocks.

    PubMed

    Blanco-Zubiaguirre, L; Arrieta, N; Iturregui, A; Martinez-Arkarazo, I; Olivares, M; Castro, K; Olazabal, M A; Madariaga, J M

    2015-11-01

    Beachrocks are consolidated coastal sedimentary formations resulting mainly from the relative rapid cementation of beach sediments by different calcium carbonate polymorphs. Although previous works have already studied the elemental composition and the mineral phases composing these cements, few of them have focused their attention on the organic matter present therein. This work describes an extraction methodology based on focused ultrasound solid-liquid extraction (FUSLE), followed by analysis using large volume injection (LVI) in a programmable temperature vaporizer (PTV) combined with gas chromatography-mass spectrometry (GC-MS) in order to determine organics such as polycyclic aromatic hydrocarbons (PAHs) and biomarkers (hopanes), which can increase and confirm the information obtained so far. This goal has been achieved after the optimization of the main parameters affecting the extraction procedure, such as, extraction solvent, FUSLE variables (amplitude, extraction time and pulse time) and also variables affecting the LVI-PTV (vent time, injection speed and cryo-focusing temperature). The developed method rendered results comparable to traditional extraction methods in terms of accuracy (77-109%) and repeatability (RSD<23%). Finally, the analyses performed over real beachrock samples from the Bay of Biscay (Northern Spain) revealed the presence of the 16 EPA priority PAHs, as well as some organic biomarkers which could increase the knowledge about such beachrock formation. PMID:26186864

  5. Rapid heating of a strongly coupled plasma at the solid-liquid phase transition

    NASA Astrophysics Data System (ADS)

    Jensen, M. J.; Hasegawa, T.; Bollinger, J. J.; Dubin, D. H. E.

    2004-11-01

    Between 10^4 and 10^6 ^9Be^+ ions are trapped in a 4.5 Tesla Penning trap and laser-cooled to ˜1 mK, where the ions form a crystalline plasma with an interparticle spacing of ˜20 μm. This system is a realization of a strongly coupled one-component plasma. Using Doppler laser spectroscopy on a single-photon transition, we measured the temperature and heating rate of this plasma when not being laser-cooled. We measured a slow heating rate of ≤ 100 mK/s due to residual gas collisions for the first 100-200 ms after turning off the cooling laser. This slow heating is followed by a rapid heating to 1-2 K in 100 ms as the plasma undergoes the solid-liquid phase transition at T=10 mK (Γ ˜ 170). We will present evidence that this rapid heating is due to a sudden release of energy from weakly cooled degrees of freedom involving the cyclotron motion of trapped impurity ions. We will also discuss the prospects for observing the latent heat associated with the phase transition.

  6. Band offsets across solid-liquid interfaces from continuum solvation methods

    NASA Astrophysics Data System (ADS)

    Sundararaman, Ravishankar; Ping, Yuan; Galli, Giulia A.; Goddard, William A., III

    2015-03-01

    The band edge positions of photo-electrodes relative to water redox potentials play an important role in determining the efficiency of the photo-electrochemical cell. Direct theoretical calculations of solid-liquid interfaces are expensive and simplified models are desirable for rapid theoretical screening of new materials. However, traditional solvation models are extensively fit to describe organic solutes and hence extrapolate poorly to highly-polar inorganic surfaces. We develop minimally-empirical continuum solvation models suitable for treating such surfaces and present theoretical predictions of the band positions of rutile TiO2 (110) and WO3 (001) surfaces in water. We obtain non-negligible solvation effects ~ 1-2 eV, in good agreement with experimental results. This material is based upon work performed by the Joint Center for Artificial Photosynthesis, a DOE Energy Innovation Hub, supported through the Office of Science of the U.S. Department of Energy under Award Number DE-SC0004993.

  7. Rheological Aspects of the Solid-Liquid Transition in Jammed Systems

    NASA Astrophysics Data System (ADS)

    Coussot, P.

    A common property of jammed systems is a yield stress they have to overcome in order to start to flow. In rheology it is generally assumed that the corresponding solid-liquid transition is continuous, the steady state viscosity progressively decreasing from infinity to a finite value as the applied shear stress is increased beyond the yield stress. Recent experiments with various materials such as colloidal suspensions, foams, emulsions, or polymer gels, show that this transition is in fact abrupt: in steady state, at a critical stress the material viscosity abruptly turns from infinity to a finite value. This phenomenon corresponds to another effect observed from MRI-rheometry tests: in steady state such pasty materials either flow at a sher rate larger than a critical, finite value, associated to a critical stress, or do not flow at all. This phenomenon has also a dynamic character, which is in particular illustrated by the "viscosity bifurcation" in time under controlled stress: below the critical stress value the shear rate progressively decreases until reaching stoppage; beyond this critical stress the shear rate increases and reaches a finite value. Moreover for a material initially at rest the interface between the sheared and unsheared regions, i.e. the slope break, progressively reaches its asymptotic position in time. From these results we deduce that usual macroscopic observations basically reflect complex space and time evolutions of flow and material characteristics in the rheometer gap, rather than local time-dependent properties.

  8. Simulations of solid-liquid friction at ice-Ih/water interfaces

    NASA Astrophysics Data System (ADS)

    Louden, Patrick B.; Gezelter, J. Daniel

    2013-11-01

    We have investigated the structural and dynamic properties of the basal and prismatic facets of the ice Ih/water interface when the solid phase is drawn through the liquid (i.e., sheared relative to the fluid phase). To impose the shear, we utilized a velocity-shearing and scaling approach to reverse non-equilibrium molecular dynamics. This method can create simultaneous temperature and velocity gradients and allow the measurement of transport properties at interfaces. The interfacial width was found to be independent of the relative velocity of the ice and liquid layers over a wide range of shear rates. Decays of molecular orientational time correlation functions gave similar estimates for the width of the interfaces, although the short- and longer-time decay components behave differently closer to the interface. Although both facets of ice are in "stick" boundary conditions in liquid water, the solid-liquid friction coefficients were found to be significantly different for the basal and prismatic facets of ice.

  9. Influence of dielectric properties on van der Waals/Casimir forces in solid-liquid systems

    SciTech Connect

    Zwol, P. J. van; Palasantzas, G.; De Hosson, J. Th. M.

    2009-05-15

    In this paper, we present calculations of van der Waals/Casimir forces, described by Lifshitz theory, for the solid-liquid-solid system using measured dielectric functions of all involved materials for the wavelength range from millimeters down to subnanometers. It is shown that even if the dielectric function is known over all relevant frequency ranges, the scatter in the dielectric data can lead to very large scatter in the calculated van der Waals/Casimir forces. Especially when the liquid dielectric function becomes comparable in magnitude to the dielectric function of one of the interacting solids, the associated variation in the force can be up to a factor of 2 for plate-plate separations 5-500 nm. This corresponds to an uncertainty up to 100% in the theory prediction for a specific system. As a result accuracy testing of the Lifshitz theory under these circumstances is rather questionable. Finally we discuss predictions of Lifshitz theory regarding multiple repulsive-attractive transitions with separation distance, as well as nontrivial scaling of the van der Waals/Casimir force with distance.

  10. How solid-liquid adhesive property regulates liquid slippage on solid surfaces?

    PubMed

    Xue, Yahui; Wu, Yang; Pei, Xiaowei; Duan, Huiling; Xue, Qunji; Zhou, Feng

    2015-01-13

    The influence of solid-liquid adhesive property on liquid slippage at solid surfaces has been investigated using experiment approach on well-defined model surfaces as well as theoretical analysis. Based on a classical molecular-kinetic description for molecular and hydrodynamic slip, we propose a simple theoretical model that directly relates the liquid slip length to the liquid adhesive force on solid surfaces, which yields an exponential decay function. Well-defined smooth surfaces with varied surface wettability/adhesion are fabricated by forming self-assembled monolayers on gold with different mole ratios of hydrophobic and hydrophilic thiols. The adhesive force of a water droplet and the molecular slippage on these surfaces are probed by surface force apparatus and quartz crystal microbalance measurements, respectively. The experiment results are well consistent with our theoretical prediction. Our finding benefits the understanding of the underlying mechanism of liquid slippage on solid surfaces at molecular level and the rational design of microfluidics with an aim to be frictionless or highly controllable. PMID:25511171

  11. Coarsening in Solid-liquid Mixtures: Overview of Experiments on Shuttle and ISS

    NASA Technical Reports Server (NTRS)

    Duval, Walter M. B.; Hawersaat, Robert W.; Lorik, T.; Thompson, J.; Gulsoy, B.; Voorhees, P. W.

    2013-01-01

    The microgravity environment on the Shuttle and the International Space Station (ISS) provides the ideal condition to perform experiments on Coarsening in Solid-Liquid Mixtures (CSLM) as deleterious effects such as particle sedimentation and buoyancy-induced convection are suppressed. For an ideal system such as Lead-Tin in which all the thermophysical properties are known, the initial condition in microgravity of randomly dispersed particles with local clustering of solid Tin in eutectic liquid Lead-Tin matrix, permitted kinetic studies of competitive particle growth for a range of volume fractions. Verification that the quenching phase of the experiment had negligible effect of the spatial distribution of particles is shown through the computational solution of the dynamical equations of motion, thus insuring quench-free effects from the coarsened microstructure measurements. The low volume fraction experiments conducted on the Shuttle showed agreement with transient Ostwald ripening theory, and the steady-state requirement of LSW theory was not achieved. More recent experiments conducted on ISS with higher volume fractions have achieved steady-state condition and show that the kinetics follows the classical diffusion limited particle coarsening prediction and the measured 3D particle size distribution becomes broader as predicted from theory.

  12. Enhanced mass transfer during solid liquid extraction of gamma-irradiated red beetroot

    NASA Astrophysics Data System (ADS)

    Nayak, Chetan A.; Chethana, S.; Rastogi, N. K.; Raghavarao, K. S. M. S.

    2006-01-01

    The exposure to gamma-irradiation pretreatment increases cell wall permeabilization, resulting in loss of turgor pressure, which led to the increase of extractability of betanin from red beetroot. The degree of extraction of betanin was investigated using gamma irradiation as a pretreatment prior to the solid-liquid extraction process and compared with control beetroot samples. The beetroot subjected to different doses of gamma irradiation (2.5, 5.0, 7.5, 10.0 kGy) and control was dipped in an acetic acid medium (1% v/v) to extract the betanin. The diffusion coefficients for betanin as well as ionic component were estimated considering Fickian diffusion. The results indicated an increase in the diffusion coefficient of betanin (0.302×10 -9-0.463×10 -9 m 2/s) and ionic component (0.248×10 -9-0.453×10 -9 m 2/s) as the dose rate increased (from 2.5 to 10.0 kGy). The degradation constant was found to increase (0.050-0.079 min -1) with an increase gamma-irradiation doses (2.5-10.0 kGy), indicating lower stability of the betanin as compared to control sample at 65 °C.

  13. Numerical formulation for the prediction of solid/liquid change of a binary alloy

    NASA Technical Reports Server (NTRS)

    Schneider, G. E.; Tiwari, S. N.

    1990-01-01

    A computational model is presented for the prediction of solid/liquid phase change energy transport including the influence of free convection fluid flow in the liquid phase region. The computational model considers the velocity components of all non-liquid phase change material control volumes to be zero but fully solves the coupled mass-momentum problem within the liquid region. The thermal energy model includes the entire domain and uses an enthalpy like model and a recently developed method for handling the phase change interface nonlinearity. Convergence studies are performed and comparisons made with experimental data for two different problem specifications. The convergence studies indicate that grid independence was achieved and the comparison with experimental data indicates excellent quantitative prediction of the melt fraction evolution. Qualitative data is also provided in the form of velocity vector diagrams and isotherm plots for selected times in the evolution of both problems. The computational costs incurred are quite low by comparison with previous efforts on solving these problems.

  14. Solid/liquid extraction equilibria of phenolic compounds with trioctylphosphine oxide impregnated in polymeric membranes.

    PubMed

    Praveen, Prashant; Loh, Kai-Chee

    2016-06-01

    Trioctylphosphine oxide based extractant impregnated membranes (EIM) were used for extraction of phenol and its methyl, hydroxyl and chloride substituted derivatives. The distribution coefficients of the phenols varied from 2 to 234, in the order of 1-napthol > p-chlorophenol > m-cresol > p-cresol > o-cresol > phenol > catechol > pyrogallol > hydroquinone, when initial phenols loadings was varied in 100-2000 mg/L. An extraction model, based on the law of mass action, was formulated to predict the equilibrium distribution of the phenols. The model was in excellent agreement (R(2) > 0.97) with the experimental results at low phenols concentrations (<800 mg/L). At higher phenols loadings though, Langmuir isotherm was better suited for equilibrium prediction (R(2) > 0.95), which signified high mass transfer resistance in the EIMs. Examination of the effects of ring substitution on equilibrium, and bivariate statistical analysis between the amounts of phenols extracted into the EIMs and factors affecting phenols interaction with TOPO, indicated the dominant role of hydrophobicity in equilibrium determination. These results improve understanding of the solid/liquid equilibrium process between phenols and the EIMs, and these will be useful in designing phenol recovery process from wastewater. PMID:27031803

  15. Vapor-Induced Solid-Liquid-Solid Process for Silicon-based Nanowire Growth

    SciTech Connect

    Zhang, Jiguang; Liu, Jun; Wang, Donghai; Choi, Daiwon; Fifield, Leonard S.; Wang, Chong M.; Xia, Guanguang; Nie, Zimin; Yang, Zhenguo; Pederson, Larry R.; Graff, Gordon L.

    2010-03-10

    Silicon based nanowires have been grown from commercial silicon powders under conditions of differing oxygen and carbon activities. Nanowires grown in the presence of carbon sources consisted of a crystalline SiC core with an amorphous SiOx shell. The thickness of SiOx shell decreased as the oxygen concentration in the precursor gases was lowered. Nanowires grown in a carbon-free environment consisted of amorphous silicon oxide with a typical composition of SiO1.8. The growth rate of nanowires decreased with decreasing oxygen content in the precursor gases. SiO1.8 nanowires exhibited an initial discharge capacity of ~ 1,300 mAh/g and better stability than those of silicon powders. A Vapor Induced Solid-Liquid-Solid (VI-SLS) mechanism is proposed to explain the nanowire growth (including silicon and other metal based nanowires) from powder sources. In this approach, both a gas source and a solid powder source are required for nanowire growth. This mechanism is consistent with experimental observations and can also be used to guide the design and growth of other nanowires.

  16. DETERMINATION OF SOLID-LIQUID EQUILIBRIA DATA FOR MIXTURES OF HEAVY HYDROCARBONS IN A LIGHT SOLVENT

    SciTech Connect

    F.V. Hanson; J.V. Fletcher; Karthik R.

    2003-06-01

    A methodology was developed using an FT-IR spectroscopic technique to obtain solid-liquid equilibria (SLE) data for mixtures of heavy hydrocarbons in significantly lighter hydrocarbon diluents. SLE was examined in multiple Model Oils that were assembled to simulate waxes. The various Model oils were comprised of C-30 to C-44 hydrocarbons in decane. The FT-IR technique was used to identify the wax precipitation temperature (WPT). The DSC technique was also used in the identification of the onset of the two-phase equilibrium in this work. An additional Model oil made up of C-20 to C-30 hydrocarbons in decane was studied using the DSC experiment. The weight percent solid below the WPT was calculated using the FT-IR experimental results. The WPT and the weight percent solid below the WPT were predicted using an activity coefficient based thermodynamic model. The FT-IR spectroscopy method is found to successfully provide SLE data and also has several advantages over other laboratory-based methods.

  17. Visual investigation of solid-liquid phase equilibria for nonflammable mixed refrigerant

    NASA Astrophysics Data System (ADS)

    Lee, C.; Yoo, J.; Park, I.; Park, J.; Cha, J.; Jeong, S.

    2015-12-01

    Non-flammable mixed refrigerant (NF-MR) Joule Thomson (J-T) refrigerators have desirable characteristics and wide cooling temperature range compared to those of pure J-T refrigerators. However, the operating challenge due to freezing is a critical issue to construct this refrigerator. In this paper, the solid-liquid phase equilibria (i.e. freezing point) of the NF-MR which is composed of Argon, R14 (CF4), and R218 (C3F8), has been experimentally investigated by a visualized apparatus. Argon, R14 and R218 mixtures are selected to be effectively capable of reaching 100 K in the MR J-T refrigerator system. Freezing points of the mixtures have been measured with the molar compositions from 0.1 to 0.8 for each component. Each test result is simultaneously acquired by a camcorder for visual inspection and temperature measurement during a warming process. Experimental results show that the certain mole fraction of Argon, R14, and R218 mixture can achieve remarkably low freezing temperature even below 77 K. This unusual freezing point depression characteristic of the MR can be a useful information for designing a cryogenic MR J-T refrigerator to reach further down to 77 K.

  18. Visualization of the solid-liquid equilibria for non-flammable mixed refrigerants

    NASA Astrophysics Data System (ADS)

    Lee, Cheonkyu; Yoo, Junghyun; Lee, Jisung; Jeong, Sangkwon

    2016-04-01

    Non-flammable mixed refrigerant (NF-MR) Joule Thomson (J-T) refrigerators have desirable characteristics and wide cooling temperature range compared to those of pure J-T refrigerators. However, the operating challenge due to freezing is a critical issue to realize this type of refrigerator. In this paper, the solid-liquid phase equilibria (i.e. freezing point) of the NF-MR which is composed of Argon (Ar), R14 (CF4), and R218 (C3F8), has been experimentally investigated by a visualized apparatus. The accuracy of the apparatus is experimentally verified with pure refrigerants and selected binary mixed refrigerants. Freezing points of the ternary NF-MRs have been measured with the molar compositions from 0.1 to 0.8 for each component. Each test result is simultaneously acquired by a camcorder for visual inspection and temperature measurement during a warming process. Experimental results reveal that the specific MR, with R14 molar composition higher than 0.4, can achieve remarkably low freezing temperature even below 77 K. These unusual freezing point depression characteristics of the MR can be a useful information for designing a cryogenic MR J-T refrigerator to reach temperatures less than 77 K.

  19. Molecular Dynamics Study of Freezing Point and Solid-Liquid Interfacial Free Energy of Stockmayer Fluids

    SciTech Connect

    Wang, J.; Apte, Pankaj; Morris, James R; Zeng, X.C.

    2013-01-01

    Freezing temperatures of Stockmayer fluids with different dipolar strength at zero pressure are estimated and computed using three independent molecular-dynamics (MD) simulation methods, namely, the superheating-undercooling method, the constant-pressure and constant-temperature (NPT) two phase coexistence method, and the constant-pressure and constant-enthalpy (NPH) coexistence method. The best estimate of the freezing temperature (in reduced unit) for the Stockmayer (SM) fluid with a reduced dipole moment is 0.656 0.001, 0.726 0.002 and 0.835 0.005, respectively. The freezing temperature increases with the dipolar strength. The solid-liquid interfacial free energies of the (111), (110) and (100) interface are calculated for the first time using two independent methods, namely, the cleaving-wall method and the interfacial fluctuation method. Both methods predict that the interfacial free energy increases with the dipole moment. Although the interfacial fluctuation method suggests a weaker interfacial anisotropy, particularly for strongly dipolar SM fluids, both methods predicted the same trend of interfacial anisotropy, that is, .

  20. Research on the pattern of solid-liquid two-phase distribution in chemical process pump

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Jiang, Y.; Han, Z. J.

    2012-11-01

    In order to explore the pattern of solid-liquid two-phase flow distribution in first stage of double-suction impeller and the double volute channel of the HD type petrol-chemical process pump, the flow field in double-suction impeller and double volute is simulated with the CFD software, by taking the Reynolds Averaged Navier Stokes equations as its governing equations, and the standard k-ε model for turbulence, derives the pattern of solid particle concentration distribution in the impeller and double volute channel under different initial particle concentrations and different particle diameters. The results show that in the double-suction impeller, solid phase distribution changes a lot along with the increase of initial particle concentration; the concentration near the back side is higher than the face side. Solid particles have the motion trend to the back side of blade in double-suction impeller along with the increase of particle diameters. In double volute channel, solid phase concentration distribution is uneven and solid particle concentration is relatively higher from section 1 to section 8. In the diffusion section, concentration is high in lateral side and low in medial side, the solid particles have the motion trend to the lateral side and the solid particle concentration is relatively higher.

  1. Microscopic thin film optical anisotropy imaging at the solid-liquid interface

    NASA Astrophysics Data System (ADS)

    Miranda, Adelaide; De Beule, Pieter A. A.

    2016-04-01

    Optical anisotropy of thin films has been widely investigated through ellipsometry, whereby typically an optical signal is averaged over a ˜1 cm2 elliptical area that extends with increasing angle-of-incidence (AOI). Here, we report on spectroscopic imaging ellipsometry at the solid-liquid interface applied to a supported lipid bilayer (SLB). We detail how a differential spectrally resolved ellipsometry measurement, between samples with and without optically anisotropic thin film on an absorbing substrate, can be applied to recover in and out of plane refractive indices of the thin film with known film thickness, hence determining the thin film optical anisotropy. We also present how optimal wavelength and AOI settings can be determined ensuring low parameter cross correlation between the refractive indices to be determined from a differential measurement in Δ ellipsometry angle. Furthermore, we detail a Monte Carlo type analysis that allows one to determine the minimal required optical ellipsometry resolution to recover a given thin film anisotropy. We conclude by presenting a new setup for a spectroscopic imaging ellipsometry based on fiber supercontinuum laser technology, multi-wavelength diode system, and an improved liquid cell design, delivering a 5 ×-10 × ellipsometric noise reduction over state-of-the-art. We attribute this improvement to increased ellipsometer illumination power and a reduced light path in liquid through the use of a water dipping objective.

  2. Microscopic thin film optical anisotropy imaging at the solid-liquid interface.

    PubMed

    Miranda, Adelaide; De Beule, Pieter A A

    2016-04-01

    Optical anisotropy of thin films has been widely investigated through ellipsometry, whereby typically an optical signal is averaged over a ∼1 cm(2) elliptical area that extends with increasing angle-of-incidence (AOI). Here, we report on spectroscopic imaging ellipsometry at the solid-liquid interface applied to a supported lipid bilayer (SLB). We detail how a differential spectrally resolved ellipsometry measurement, between samples with and without optically anisotropic thin film on an absorbing substrate, can be applied to recover in and out of plane refractive indices of the thin film with known film thickness, hence determining the thin film optical anisotropy. We also present how optimal wavelength and AOI settings can be determined ensuring low parameter cross correlation between the refractive indices to be determined from a differential measurement in Δ ellipsometry angle. Furthermore, we detail a Monte Carlo type analysis that allows one to determine the minimal required optical ellipsometry resolution to recover a given thin film anisotropy. We conclude by presenting a new setup for a spectroscopic imaging ellipsometry based on fiber supercontinuum laser technology, multi-wavelength diode system, and an improved liquid cell design, delivering a 5 ×-10 × ellipsometric noise reduction over state-of-the-art. We attribute this improvement to increased ellipsometer illumination power and a reduced light path in liquid through the use of a water dipping objective. PMID:27131681

  3. Solid-liquid interface free energies of pure bcc metals and B2 phases

    DOE PAGESBeta

    Wilson, S. R.; Gunawardana, K. G. S. H.; Mendelev, M. I.

    2015-04-07

    The solid-liquid interface (SLI) free energy was determined from molecular dynamics (MD) simulation for several body centered cubic (bcc) metals and B2 metallic compounds (space group: Pm3¯m ; prototype: CsCl). In order to include a bcc metal with a low melting temperature in our study, a semi-empirical potential was developed for Na. Two additional synthetic “Na” potentials were also developed to explore the effect of liquid structure and latent heat on the SLI free energy. The obtained MD data were compared with the empirical Turnbull, Laird, and Ewing relations. All three relations are found to predict the general trend observedmore » in the MD data for bcc metals obtained within the present study. However, only the Laird and Ewing relations are able to predict the trend obtained within the sequence of “Na” potentials. The Laird relation provides the best prediction for our MD data and other MD data for bcc metals taken from the literature. Overall, the Laird relation also agrees well with our B2 data but requires a proportionality constant that is substantially different from the bcc case. It also fails to explain a considerable difference between the SLI free energies of some B2 phases which have nearly the same melting temperature. In contrast, this difference is satisfactorily described by the Ewing relation. Thus, the Ewing relation obtained from the bcc dataset also provides a reasonable description of the B2 data.« less

  4. Solid-liquid interface free energies of pure bcc metals and B2 phases

    SciTech Connect

    Wilson, S. R.; Gunawardana, K. G. S. H.; Mendelev, M. I.

    2015-04-07

    The solid-liquid interface (SLI) free energy was determined from molecular dynamics (MD) simulation for several body centered cubic (bcc) metals and B2 metallic compounds (space group: Pm3¯m ; prototype: CsCl). In order to include a bcc metal with a low melting temperature in our study, a semi-empirical potential was developed for Na. Two additional synthetic “Na” potentials were also developed to explore the effect of liquid structure and latent heat on the SLI free energy. The obtained MD data were compared with the empirical Turnbull, Laird, and Ewing relations. All three relations are found to predict the general trend observed in the MD data for bcc metals obtained within the present study. However, only the Laird and Ewing relations are able to predict the trend obtained within the sequence of “Na” potentials. The Laird relation provides the best prediction for our MD data and other MD data for bcc metals taken from the literature. Overall, the Laird relation also agrees well with our B2 data but requires a proportionality constant that is substantially different from the bcc case. It also fails to explain a considerable difference between the SLI free energies of some B2 phases which have nearly the same melting temperature. In contrast, this difference is satisfactorily described by the Ewing relation. Thus, the Ewing relation obtained from the bcc dataset also provides a reasonable description of the B2 data.

  5. High Frequency Acoustic Reflectometry for Solid/Liquid Interface Characterization: Application to Droplet Evaporation

    NASA Astrophysics Data System (ADS)

    Carlier, Julien; Toubal, Malika; Li, Sizhe; Campistron, Pierre; Callens, Dorothée; Thomy, Vincent; Senez, Vincent; Nongaillard, Bertrand

    Evolution of the local concentration in a 1 μL droplet of ethanol/water mixture during an evaporation process has been followed using high frequency acoustic reflectometry. This method has been developed for wetting characterization on micro/nanostructures and makes it possible to follow concentration evolution in a droplet deposited on a solid surface. This information gives the opportunity to predict wetting depending on surface tension linked to alcohol concentration evolution. The calibration of the method and concentration evolution in 50% and 30% ethanol droplets are presented. The evolution of a pure ethanol droplet composition is tracked so as to follow hydration process.

  6. In-drop capillary spooling of spider capture thread inspires hybrid fibers with mixed solid-liquid mechanical properties.

    PubMed

    Elettro, Hervé; Neukirch, Sébastien; Vollrath, Fritz; Antkowiak, Arnaud

    2016-05-31

    An essential element in the web-trap architecture, the capture silk spun by ecribellate orb spiders consists of glue droplets sitting astride a silk filament. Mechanically this thread presents a mixed solid-liquid behavior unknown to date. Under extension, capture silk behaves as a particularly stretchy solid, owing to its molecular nanosprings, but it totally switches behavior in compression to now become liquid-like: It shrinks with no apparent limit while exerting a constant tension. Here, we unravel the physics underpinning the unique behavior of this "liquid wire" and demonstrate that its mechanical response originates in the shape-switching of the silk filament induced by buckling within the droplets. Learning from this natural example of geometry and mechanics, we manufactured programmable liquid wires that present previously unidentified pathways for the design of new hybrid solid-liquid materials. PMID:27185930

  7. Hot Electrons at Solid-Liquid Interfaces: A Large Chemoelectric Effect during the Catalytic Decomposition of Hydrogen Peroxide.

    PubMed

    Nedrygailov, Ievgen I; Lee, Changhwan; Moon, Song Yi; Lee, Hyosun; Park, Jeong Young

    2016-08-26

    The study of energy and charge transfer during chemical reactions on metals is of great importance for understanding the phenomena involved in heterogeneous catalysis. Despite extensive studies, very little is known about the nature of hot electrons generated at solid-liquid interfaces. Herein, we report remarkable results showing the detection of hot electrons as a chemicurrent generated at the solid-liquid interface during decomposition of hydrogen peroxide (H2 O2 ) catalyzed on Schottky nanodiodes. The chemicurrent reflects the activity of the catalytic reaction and the state of the catalyst in real time. We show that the chemicurrent yield can reach values up to 10(-1) electrons/O2 molecule, which is notably higher than that for solid-gas reactions on similar nanodiodes. PMID:27374493

  8. Study of the generation characteristics of laser converters with dye-based wide-aperture solid--liquid active elements

    SciTech Connect

    Eremenko, A.S.; Zemskii, V.I.; Kolesnikov, Y.L.; Malinin, B.G.; Meshkovsky, I.K.; Savkin, N.P.; Stepanov, V.E.; Shildyaev, V.S.

    1986-11-01

    The lasing characteristics of an active element, consisting of a fine porous silicate matrix, has been studied. Molecules of a dye (rhodamine 6G) and an ethanol solution of the same dye were introduced into the cells. It has been shown that under conditions of large heat release (when thermooptical distortions begin to appear in the dye solutions), the solid--liquid element preserves the stability of its own lasing characteristics.

  9. ZnO nanoneedle/H2O solid-liquid heterojunction-based self-powered ultraviolet detector

    PubMed Central

    2013-01-01

    ZnO nanoneedle arrays were grown vertically on a fluorine-doped tin oxide-coated glass by hydrothermal method at a relatively low temperature. A self-powered photoelectrochemical cell-type UV detector was fabricated using the ZnO nanoneedles as the active photoanode and H2O as the electrolyte. This solid-liquid heterojunction offers an enlarged ZnO/water contact area and a direct pathway for electron transport simultaneously. By connecting this UV photodetector to an ammeter, the intensity of UV light can be quantified using the output short-circuit photocurrent without a power source. High photosensitivity, excellent spectral selectivity, and fast photoresponse at zero bias are observed in this UV detector. The self-powered behavior can be well explained by the formation of a space charge layer near the interface of the solid-liquid heterojunction, which results in a built-in potential and makes the solid-liquid heterojunction work in photovoltaic mode. PMID:24103153

  10. Thermodynamic and rheological properties of solid-liquid systems in coal processing. Quarterly technical report, October 1--December 31, 1994

    SciTech Connect

    Kabadi, V.N.; Ilias, S.

    1995-10-01

    The objective of this project is to develop a model for solid-liquid equilibria and a model for viscosities of the products of coal liquefaction processes. The same characterization procedure and representation by continuous distributions as used in previous work on vapor-liquid equilibria and excess enthalpies of coal liquids will be used. Models when fully developed will give the solid-liquid phase equilibrium properties and viscosities as factors of temperature and pressure for known molecular weight distribution and structural characterization of the coal liquid. To accomplish this well, the project requires three tasks: (1) Solid-Liquid phase equilibrium model development; (2) Experimental Viscosity Measurements; and (3) Viscosity Model Development. The work on development of a predictive model for saturated liquid volumes of coal model compounds has been completed. A manuscript has been prepared for submission to AIChE Journal. A copy of the manuscript is attached. Work on extending the viscosity model to coal derived liquids is continuing and progress on this work will be included in the next report.

  11. A molecular dynamics study to determine the solid-liquid interfacial tension using test area simulation method (TASM)

    NASA Astrophysics Data System (ADS)

    Nair, Anjan R.; Sathian, Sarith P.

    2012-08-01

    Molecular dynamics (MD) studies on heat transfer from a heated nanoparticle into the surrounding fluid have indicated that the fluid next to a spherical nanoparticle can get heated well above its boiling point without observing a phase change, while a contradicting behavior was observed for a flat surface-fluid interface. Another interesting observation is that the critical heat flux was found to increase with increase in the wetting characteristics of solid. Thus, the interfacial tension or free energy of solid-liquid interface could play a pivotal role in the mechanism of heat transfer. A recent study by Gloor et al. [J. Chem. Phys. 123, 134703 (2005)], 10.1063/1.2038827 has proposed test area simulation method (TASM) for the determination of interfacial tension. The present study involves the determination and the comparison of solid-liquid interfacial tension for planar and spherical interfaces using MD based on TASM and analyze the results. A higher interfacial tension value is observed for spherical nanoparticle fluid interface compared to flat surface fluid interface. The results also indicate that the solid-liquid interfacial tension is a size and temperature dependent property. The results from this study are also expected to give better insights into the possible reasons for the observed differences in the thermal transport for spherical nanoparticle-liquid interface compared to planar-liquid interface.

  12. Experimental studies on irreversibility of electrostatic adsorption of silica nanoparticles at solid-liquid interface.

    PubMed

    Li, Xue; Niitsoo, Olivia; Couzis, Alexander

    2014-04-15

    Adsorption of colloidal nanoparticles (NPs) at solid-liquid interface is a scientifically interesting and technologically important phenomenon due to its fundamental importance in many industrial, environmental, and biological processes, such as wastewater treatment, printing, coating of surfaces, chromatography, papermaking, or biocompatibility. The process is well understood theoretically by the random sequential adsorption (RSA) model, based on the assumption of irreversible adsorption. Irreversible adsorption is defined as a process in which, once adsorbed, a particle can neither desorb, nor to move laterally on the surface. However, published experimental data that verifies the irreversibility of particle adsorption are very limited. In this study, we demonstrate the irreversibility of electrostatically driven nanoparticle adsorption utilizing a carefully selected set of experiments. A simple method was employed by uniquely introducing Ag@SiO2 core/shell NPs to perform exchange adsorptions experiments. Stöber SiO2 NPs with a diameter of 50-80 nm were initially electrostatically adsorbed onto amino-functionalized silicon wafer substrates followed by the subsequent adsorption of Ag@SiO2 NPs. The Ag@SiO2 NPs have the same surface chemistry as the neat SiO2 NPs. For the second step the adsorption time was varied from 1 min to 1 week so as to get a thorough understanding of the process irreversibility. Surface coverage quantification has shown that the surface coverage of the initially adsorbed SiO2 NPs stays the same independent of the duration of the second step adsorption using the Ag@SiO2 core/shell NPs. This observation directly confirms the irreversibility of electrostatic adsorption of NPs. PMID:24559699

  13. Universality and criticality of a second-order granular solid-liquid-like phase transition

    NASA Astrophysics Data System (ADS)

    Castillo, Gustavo; Mujica, Nicolás; Soto, Rodrigo

    2015-01-01

    We experimentally study the critical properties of the nonequilibrium solid-liquid-like transition that takes place in vibrated granular matter. The critical dynamics is characterized by the coupling of the density field with the bond-orientational order parameter Q4, which measures the degree of local crystallization. Two setups are compared, which present the transition at different critical accelerations as a result of modifying the energy dissipation parameters. In both setups five independent critical exponents are measured, associated to different properties of Q4: the correlation length, relaxation time, vanishing wavenumber limit (static susceptibility), the hydrodynamic regime of the pair correlation function, and the amplitude of the order parameter. The respective critical exponents agree in both setups and are given by ν⊥=1 ,ν∥=2 ,γ =1 ,η ≈0.6 -0.67 , and β =1 /2 , whereas the dynamical critical exponent is z =ν∥/ν⊥=2 . The agreement on five exponents is an exigent test for the universality of the transition. Thus, while dissipation is strictly necessary to form the crystal, the path the system undergoes toward the phase separation is part of a well-defined universality class. In fact, the local order shows critical properties while density does not. Being the later conserved, the appropriate model that couples both is model C in the Hohenberg and Halperin classification. The measured exponents are in accord with the nonequilibrium extension to model C if we assume that α , the exponent associated in equilibrium to the specific heat divergence but with no counterpart in this nonequilibrium experiment, vanishes.

  14. Linear morphological stability analysis of the solid-liquid interface in rapidsolidification of a binary system

    NASA Astrophysics Data System (ADS)

    Galenko, P. K.; Danilov, D. A.

    2004-05-01

    The interface stability against small perturbations of the planar solid-liquid interface is considered analytically in linear approximation. Following the analytical procedure of Trivedi and Kurz [

    R. Trivedi and W. Kurz, Acta Metall. 34, 1663 (1986)
    ], which is advancing the original treatment of morphological stability by Mullins and Sekerka [
    W. W. Mullins and R. F. Sekerka, J. Appl. Phys. 35, 444 (1964)
    ] to the case of rapid solidification, we extend the model by introducing the local nonequilibrium in the solute diffusion field around the interface. A solution to the heat- and mass-transport problem around the perturbed interface is given in the presence of the local nonequilibrium solute diffusion. Using the developing local nonequilibrium model of solidification, the self-consistent analysis of linear morphological stability is presented with the attribution to the marginal (neutral) and absolute morphological stability of a rapidly moving interface. Special consideration of the interface stability for the cases of solidification in negative and positive thermal gradients is given. A quantitative comparison of the model predictions for the absolute morphological stability is presented with regard to experimental results of Hoglund and Aziz [ D. E. Hoglund and M. J. Aziz, in Kinetics of Phase Transformations, edited by M.O. Thompson, M. J. Aziz, and G. B. Stephenson, MRS Symposia Proceedings No. 205 (Materials Research Society, Pittsburgh, 1991), p. 325 ] on critical solute concentration for the interface breakdown during rapid solidification of Si-Sn alloys.

  15. A Bottom-Up Approach to Understanding Protein Layer Formation at Solid-Liquid Interfaces

    PubMed Central

    Kastantin, Mark; Langdon, Blake B.; Schwartz, Daniel K.

    2014-01-01

    A common goal across different fields (e.g. separations, biosensors, biomaterials, pharmaceuticals) is to understand how protein behavior at solid-liquid interfaces is affected by environmental conditions. Temperature, pH, ionic strength, and the chemical and physical properties of the solid surface, among many factors, can control microscopic protein dynamics (e.g. adsorption, desorption, diffusion, aggregation) that contribute to macroscopic properties like time-dependent total protein surface coverage and protein structure. These relationships are typically studied through a top-down approach in which macroscopic observations are explained using analytical models that are based upon reasonable, but not universally true, simplifying assumptions about microscopic protein dynamics. Conclusions connecting microscopic dynamics to environmental factors can be heavily biased by potentially incorrect assumptions. In contrast, more complicated models avoid several of the common assumptions but require many parameters that have overlapping effects on predictions of macroscopic, average protein properties. Consequently, these models are poorly suited for the top-down approach. Because the sophistication incorporated into these models may ultimately prove essential to understanding interfacial protein behavior, this article proposes a bottom-up approach in which direct observations of microscopic protein dynamics specify parameters in complicated models, which then generate macroscopic predictions to compare with experiment. In this framework, single-molecule tracking has proven capable of making direct measurements of microscopic protein dynamics, but must be complemented by modeling to combine and extrapolate many independent microscopic observations to the macro-scale. The bottom-up approach is expected to better connect environmental factors to macroscopic protein behavior, thereby guiding rational choices that promote desirable protein behaviors. PMID:24484895

  16. Digestion of frozen/thawed food waste in the hybrid anaerobic solid-liquid system

    SciTech Connect

    Stabnikova, O. Liu, X.Y.; Wang, J.Y.

    2008-07-01

    The hybrid anaerobic solid-liquid (HASL) system, which is a modified two-phase anaerobic digester, is to be used in an industrial scale operation to minimize disposal of food waste at incineration plants in Singapore. The aim of the present research was to evaluate freezing/thawing of food waste as a pre-treatment for its anaerobic digestion in the HASL system. The hydrolytic and fermentation processes in the acidogenic reactor were enhanced when food waste was frozen for 24 h at -20 deg. C and then thawed for 12 h at 25 deg. C (experiment) in comparison with fresh food waste (control). The highest dissolved COD concentrations in the leachate from the acidogenic reactors were 16.9 g/l on day 3 in the control and 18.9 g/l on day 1 in the experiment. The highest VFA concentrations in the leachate from the acidogenic reactors were 11.7 g/l on day 3 in the control and 17.0 g/l on day 1 in the experiment. The same volume of methane was produced during 12 days in the control and 7 days in the experiment. It gave the opportunity to diminish operational time of batch process by 42%. The effect of freezing/thawing of food waste as pre-treatment for its anaerobic digestion in the HASL system was comparable with that of thermal pre-treatment of food waste at 150 deg. C for 1 h. However, estimation of energy required either to heat the suspended food waste to 150 deg. C or to freeze the same quantity of food waste to -20 deg. C showed that freezing pre-treatment consumes about 3 times less energy than thermal pre-treatment.

  17. Solid-liquid separation by sonochemistry: a new approach for the separation of mineral suspensions.

    PubMed

    Nakamura, Takashi; Okawa, Hirokazu; Kawamura, Youhei; Sugawara, Katsuyasu

    2011-01-01

    The effect of sonochemistry to acidify solutions was applied for the solid-liquid separation of three kinds of mineral suspensions. At first, the relationship was measured between zeta-potential and pH in these suspensions to find pH levels correspondent to the isoelectric points. Then sonication (200 kHz or 28 kHz) was applied to adjust pH to the isoelectric points and separated particles from solutions by still-standing and spontaneous precipitation. Compared to the conventional methods using filters and chemical agents, the advantage of this sonochemical separation is two-fold. First, it does not require the maintenance of filters. Second, separated particles are easy to use since they are not mixed with pH adjusters and chemical flocculants. Isoelectric zone (ion strength 0.01, concentration 0.001 wt.%) of green tuff, andesite and titanium dioxide suspensions tested in this study were pH 1.1-3.7, 0.8-3.4, 2.7-5.7, respectively. The sonication of green tuff and andesite suspensions at 200 kHz changed the pH to the isoelectric zone despite the pH buffering effect of eluted alkali earth metals, and successfully precipitated the particles. On the contrary, the sonication of these suspensions at 28 kHz failed to adjust pH to the isoelectric zone, and the particles did not precipitate. In addition, the degradation of particles was observed in the SEM photographs of particles sonicated at 28 kHz, whereas no significant change was detected in particles sonicated at 200 kHz. Thus, it is concluded that the optimal frequency is about 200 kHz because its strong chemical effect can easily adjust the pH while its relatively weak physical effect prevents the degradation of particles. PMID:20643570

  18. Development and Optimization of a Flocculation Procedure for Improved Solid-Liquid Separation of Digested Biomass

    SciTech Connect

    Patton, Caroline; Lischeske, James J.; Sievers, David A.

    2015-11-03

    One viable treatment method for conversion of lignocellulosic biomass to biofuels begins with saccharification (thermochemical pretreatment and enzymatic hydrolysis), followed by fermentation or catalytic upgrading to fuels such as ethanol, butanol, or other hydrocarbons. The post-hydrolysis slurry is typically 4-8 percent insoluble solids, predominantly consisting of lignin. Suspended solids are known to inhibit fermentation as well as poison catalysts and obstruct flow in catalyst beds. Thus a solid-liquid separation following enzymatic hydrolysis would be highly favorable for process economics, however the material is not easily separated by filtration or gravimetric methods. Use of a polyacrylamide flocculant to bind the suspended particles in a corn stover hydrolyzate slurry into larger flocs (1-2mm diameter) has been found to be extremely helpful in improving separation. Recent and ongoing research on novel pretreatment methods yields hydrolyzate material with diverse characteristics. Therefore, we need a thorough understanding of rapid and successful flocculation design in order to quickly achieve process design goals. In this study potential indicators of flocculation performance were investigated in order to develop a rapid analysis method for flocculation procedure in the context of a novel hydrolyzate material. Flocculation conditions were optimized on flocculant type and loading, pH, and mixing time. Filtration flux of the hydrolyzate slurry was improved 170-fold using a cationic polyacrylamide flocculant with a dosing of approximately 22 mg flocculant/g insoluble solids at an approximate pH of 3. With cake washing, sugar recovery exceeded 90 percent with asymptotic yield at 15 L wash water/kg insoluble solids.

  19. A bottom-up approach to understanding protein layer formation at solid-liquid interfaces.

    PubMed

    Kastantin, Mark; Langdon, Blake B; Schwartz, Daniel K

    2014-05-01

    A common goal across different fields (e.g. separations, biosensors, biomaterials, pharmaceuticals) is to understand how protein behavior at solid-liquid interfaces is affected by environmental conditions. Temperature, pH, ionic strength, and the chemical and physical properties of the solid surface, among many factors, can control microscopic protein dynamics (e.g. adsorption, desorption, diffusion, aggregation) that contribute to macroscopic properties like time-dependent total protein surface coverage and protein structure. These relationships are typically studied through a top-down approach in which macroscopic observations are explained using analytical models that are based upon reasonable, but not universally true, simplifying assumptions about microscopic protein dynamics. Conclusions connecting microscopic dynamics to environmental factors can be heavily biased by potentially incorrect assumptions. In contrast, more complicated models avoid several of the common assumptions but require many parameters that have overlapping effects on predictions of macroscopic, average protein properties. Consequently, these models are poorly suited for the top-down approach. Because the sophistication incorporated into these models may ultimately prove essential to understanding interfacial protein behavior, this article proposes a bottom-up approach in which direct observations of microscopic protein dynamics specify parameters in complicated models, which then generate macroscopic predictions to compare with experiment. In this framework, single-molecule tracking has proven capable of making direct measurements of microscopic protein dynamics, but must be complemented by modeling to combine and extrapolate many independent microscopic observations to the macro-scale. The bottom-up approach is expected to better connect environmental factors to macroscopic protein behavior, thereby guiding rational choices that promote desirable protein behaviors. PMID:24484895

  20. Performance Validation and Scaling of a Capillary Membrane Solid-Liquid Separation System

    SciTech Connect

    Rogers, S; Cook, J; Juratovac, J; Goodwillie, J; Burke, T

    2011-10-25

    Algaeventure Systems (AVS) has previously demonstrated an innovative technology for dewatering algae slurries that dramatically reduces energy consumption by utilizing surface physics and capillary action. Funded by a $6M ARPA-E award, transforming the original Harvesting, Dewatering and Drying (HDD) prototype machine into a commercially viable technology has required significant attention to material performance, integration of sensors and control systems, and especially addressing scaling issues that would allow processing extreme volumes of algal cultivation media/slurry. Decoupling the harvesting, dewatering and drying processes, and addressing the rate limiting steps for each of the individual steps has allowed for the development individual technologies that may be tailored to the specific needs of various cultivation systems. The primary performance metric used by AVS to assess the economic viability of its Solid-Liquid Separation (SLS) dewatering technology is algae mass production rate as a function of power consumption (cost), cake solids/moisture content, and solids capture efficiency. An associated secondary performance metric is algae mass loading rate which is dependent on hydraulic loading rate, area-specific hydraulic processing capacity (gpm/in2), filter:capillary belt contact area, and influent algae concentration. The system is capable of dewatering 4 g/L (0.4%) algae streams to solids concentrations up to 30% with capture efficiencies of 80+%, however mass production is highly dependent on average cell size (which determines filter mesh size and percent open area). This paper will present data detailing the scaling efforts to date. Characterization and performance data for novel membranes, as well as optimization of off-the-shelf filter materials will be examined. Third party validation from Ohio University on performance and operating cost, as well as design modification suggestions will be discussed. Extrapolation of current productivities

  1. The Interaction Between an Insoluble Particle and an Advancing Solid/Liquid Interface: Micro-Gravity Experiments and Theoretical Developments

    NASA Technical Reports Server (NTRS)

    Catalina, Adrian V.; Ssen, Subhayu; Stefanescu, Doru M.

    2003-01-01

    The interaction of an insoluble particle with an advancing solid/liquid interface (SLI) has been a subject of investigation for the past four decades. While the original interest stemmed from geology applications (e.g., frost heaving in soil), researchers soon realized that the complex science associated with such an interaction is relevant to many other scientific fields encompassing metal matrix composites (MMCs), high temperature superconductors, inclusion management in steel, growth of monotectics, and preservation of biological cells. During solidification of a liquid containing an insoluble particle, three distinct interaction phenomena have been experimentally observed: instantaneous engulfment of the particle, continuous pushing, and particle pushing followed by engulfment. It was also observed that for given experimental conditions and particle size there is a critical solidification velocity, V(sub cr), above which a particle is engulfed. During solidification of MMCs pushing leads to particle agglomeration at the grain boundaries and this has detrimental effects on mechanical properties of the casting. Consequently, the process must be designed for instantaneous engulfment to occur. This implies the development of accurate theoretical models to predict V(sub cr), and perform benchmark experiments to test the validity of such models. Although considerable progress has been made in understanding the pushing/engulfment phenomenon (PEP), its quantification in terms of the material and processing parameters remains a focus of research. Since natural convection currents occurring during terrestrial solidification experiments complicate the study of PEP, execution of experiments on the International Space Station (ISS) has been approved and funded by NASA. Extensive terrestrial (1g) experiments and preliminary micro-gravity (mu g) experiments on two space shuttle missions have been conducted in preparation for future experiments on the ISS. The investigated

  2. Development and utilization of optical low coherence reflectometry for the study of multiple scattering in randomly distributed solid-liquid suspensions

    NASA Astrophysics Data System (ADS)

    Randall, Summer Lockerbie

    The investigation of Optical Low Coherence Reflectometry (OLCR) for evaluation of highly scattering suspensions involves a balance between the observation of real systems and theoretical development. The main focus of this work was the development and utilization of OLCR to investigate highly scattering solid-liquid suspensions over a wide range of particle sizes, using monodispersed, bimodal, and polydispersed polystyrene nanosphere suspensions and Department of Energy (DOE) waste surrogates. The results were the first experimental demonstration that coherent optical backscattering from media with randomly distributed spherical nanoparticles is dominated by Mie resonances. Industrial process samples of various sizes and dispersity were also measured to expand the applicability of OLCR to a wide range of process needs. Current research has focused on the deconvolution of sample parameters from the tailing decay profiles of highly scattering matrices. Significant progress has been made on data analysis methods for monodispersed and more complex compositions of polystyrene suspensions and these methods have been applied to HLW surrogate suspensions and several industrial models. The research described within this dissertation has implications for measurement needs on basic science, industrial, and national laboratory levels. The scope of this research includes advancements in both fundamental understanding of multiple scattering through analysis of model systems and in development and application of the technology to current measurement needs within industry.

  3. Spontaneous mode-selection in the self-propelled motion of a solid/liquid composite driven by interfacial instability

    NASA Astrophysics Data System (ADS)

    Takabatake, Fumi; Magome, Nobuyuki; Ichikawa, Masatoshi; Yoshikawa, Kenichi

    2011-03-01

    Spontaneous motion of a solid/liquid composite induced by a chemical Marangoni effect, where an oil droplet attached to a solid soap is placed on a water phase, was investigated. The composite exhibits various characteristic motions, such as revolution (orbital motion) and translational motion. The results showed that the mode of this spontaneous motion switches with a change in the size of the solid scrap. The essential features of this mode-switching were reproduced by ordinary differential equations by considering nonlinear friction with proper symmetry.

  4. Biphasic Metal Films: Intrinsically Stretchable Biphasic (Solid-Liquid) Thin Metal Films (Adv. Mater. 22/2016).

    PubMed

    Hirsch, Arthur; Michaud, Hadrien O; Gerratt, Aaron P; de Mulatier, Séverine; Lacour, Stéphanie P

    2016-06-01

    On page 4507, S. P. Lacour and co-workers present highly conductive and stretchable solid-liquid films that are formed by physical vapor deposition of gallium onto an alloying gold layer. The image shows patterns defined by lift-off on an elastomer membrane. The magnified view is a false-color scanning electron microscopy (SEM) image (×5000) of the surface of the films under 50% applied strain, showing the liquid Ga (blue-gray) flowing between the AuGa2 /Ga clusters (gold). PMID:27273441

  5. Bubble Induced Disruption of a Planar Solid-Liquid Interface During Controlled Directional Solidification in a Microgravity Environment

    NASA Technical Reports Server (NTRS)

    Grugel, Richard N.; Brush, Lucien N.; Anilkumar, Amrutur V.

    2013-01-01

    Pore Formation and Mobility Investigation (PFMI) experiments were conducted in the microgravity environment aboard the International Space Station with the intent of better understanding the role entrained porosity/bubbles play during controlled directional solidification. The planar interface in a slowing growing succinonitrile - 0.24 wt% water alloy was being observed when a nitrogen bubble traversed the mushy zone and remained at the solid-liquid interface. Breakdown of the interface to shallow cells subsequently occurred, and was later evaluated using down-linked data from a nearby thermocouple. These results and other detrimental effects due to the presence of bubbles during solidification processing in a microgravity environment are presented and discussed.

  6. Experimental determination and prediction of (solid+liquid) phase equilibria for binary mixtures of heavy alkanes and fatty acids

    NASA Astrophysics Data System (ADS)

    Benziane, Mokhtar; Khimeche, Kamel; Dahmani, Abdellah; Nezar, Sawsen; Trache, Djalal

    2012-06-01

    Solid-liquid equilibria for three binary mixtures, n-Eicosane (1) + Lauric acid (2), n-Tetracosane (1) + Stearic acid (2), and n-Octacosane (1) + Palmitic acid (2), were measured using a differential scanning calorimeter. Simple eutectic behaviour was observed for these systems. The experimental results were correlated by means of the modified UNIFAC (Larsen and Gmehling versions), UNIQUAC and ideal models. The root-mean-square deviations of the solubility temperatures for all measured data vary from 0.26 to 3.15 K and depend on the particular model used. The best solubility correlation was obtained with the UNIQUAC model.

  7. In-Situ Observations of Interaction Between Particulate Agglomerates and an Advancing Planar Solid/Liquid Interface: Microgravity Experiments

    NASA Technical Reports Server (NTRS)

    Sen, S.; Juretzko, F.; Stefanescu, D. M.; Dhindaw, B. K.; Curreri, P. A.

    1999-01-01

    Results are reported of directional solidification experiments on particulate agglomerate pushing and engulfment by a planar solid/liquid (s/1) interface. These experiments were conducted on the Space Shuttle Columbia during the United States Microgravity Payload 4 (USMP-4) Mission. It was found that the pushing to engulfment transition velocity, V(sub ct),, for agglomerates depends not only on their effective size but also their orientation with respect to the s/l interface. The analytical model for predicting V(sub cr) of a single particle was subsequently enhanced to predict V(sub cr) of the agglomerates by considering their shape factor and orientation.

  8. In Situ Observations of Interaction Between Particulate Agglomerates and an Advancing Planar Solid/Liquid Interface: Microgravity Experiments

    NASA Technical Reports Server (NTRS)

    Sen, S.; Juretzko, F.; Stafanescu, D. M.; Dhindaw, B. K.; Curreri, P. A.

    1999-01-01

    Results are reported of directional solidification experiments on particulate agglomerate pushing and engulfment by a planar solid/liquid (s/l) interface. These experiments were conducted on the Space Shuttle Columbia during the United States Microgravity Payload 4 (USMP-4) Mission. It was found that the pushing to engulfment transition velocity, V(sub cr) for agglomerates depends not only on their effective size but also their orientation with respect to the s,1 interface. The analytical model for predicting V(sub cr) of a single particle was subsequently enhanced to predict V(sub cr) of the agglomerates by considering their shape factor and orientation.

  9. Fast contact of solid-liquid interface created high strength multi-layered cellulose hydrogels with controllable size.

    PubMed

    He, Meng; Zhao, Yanteng; Duan, Jiangjiang; Wang, Zhenggang; Chen, Yun; Zhang, Lina

    2014-02-12

    Novel onion-like and multi-layered tubular cellulose hydrogels were constructed, for the first time, from the cellulose solution in a 7% NaOH/12% urea aqueous solvent by changing the shape of the gel cores. In our findings, the contacting of the cellulose solution with the surface of the agarose gel rod or sphere loaded with acetic acid led to the close chain packing to form immediately a gel layer, as a result of the destruction of the cellulose inclusion complex by acid through inducing the cellulose self-aggregation. Subsequently, multi-layered cellulose hydrogels were fabricated via a multi-step interrupted gelation process. The size, layer thickness and inter-layer space of the multi-layered hydrogels could be controlled by adjusting the cellulose concentrations, the gel core diameter and the contacting time of the solid-liquid interface. The multi-layered cellulose hydrogels displayed good architectural stability and solvent resistance. Moreover, the hydrogels exhibited high compressive strength and excellent biocompatibility. L929 cells could adhere and proliferate on the surface of the layers and in interior space, showing great potential as tissue engineering scaffolds and cell culture carrier. This work opens up a new avenue for the construction of the high strength multi-layered cellulose hydrogels formed from inner to outside via a fast contact of solid-liquid interface. PMID:24405277

  10. Numerical determination of the interfacial energy and nucleation barrier of curved solid-liquid interfaces in binary systems

    NASA Astrophysics Data System (ADS)

    Kundin, Julia; Choudhary, Muhammad Ajmal

    2016-07-01

    The phase-field crystal (PFC) technique is a widely used approach for modeling crystal growth phenomena with atomistic resolution on mesoscopic time scales. We use a two-dimensional PFC model for a binary system based on the work of Elder et al. [Phys. Rev. B 75, 064107 (2007), 10.1103/PhysRevB.75.064107] to study the effect of the curved, diffuse solid-liquid interface on the interfacial energy as well as the nucleation barrier. The calculation of the interfacial energy and the nucleation barrier certainly depends on the proper definition of the solid-liquid dividing surface and the corresponding nucleus size. We define the position of the sharp interface at which the interfacial energy is to be evaluated by using the concept of equimolar dividing surface (re) and the minimization of the interfacial energy (rs). The comparison of the results based on both radii shows that the difference re-rs is always positive and has a limit for large cluster sizes which is comparable to the Tolman length. Furthermore, we found the real nucleation barrier for small cluster sizes, which is defined as a function of the radius rs, and compared it with the classical nucleation theory. The simulation results also show that the extracted interfacial energy as function of both radii is independent of system size, and this dependence can be reasonably described by the nonclassical Tolman formula with a positive Tolman length.

  11. Numerical simulation on the performance of the vortex pump for transporting solid-liquid two-phase with light particles

    NASA Astrophysics Data System (ADS)

    Mao, W. Y.; Song, P. Y.; Deng, Q. G.; Xu, H. J.

    2016-05-01

    With the purpose of studying performance of the vortex pump for transporting solid-liquid two-phase with light particles whose relative density smaller than 1, the numerical simulation of solid-liquid two phase flowing in the whole channel of a vortex pump with the particle diameter being 0.5 mm, 1 mm, 2 mm, 3 mm and the initial solid phase volume concentrations being 10%, 20% and 30% are respectively carried out by using the commercial software ANSYS Fluent by adopting RNG κ-ɛ turbulent flow model, Eulerian-Eulerian multi-phase flow model and SIMPLEC algorithm. The simulation results show that in the impeller region, the particles concentrate on the non-working surface of the blades, and the particles are rare on the working surface of the blades. As the initial solid phase volume concentration and particle diameter increase, the pump delivery head of vortex pump decrease. The pump delivery head of vortex pump with different initial solid phase concentrations and different particle diameters are predicted and compared with those obtained by an empirical formula, and they shows good agreement.

  12. Total enthalpy-based lattice Boltzmann method with adaptive mesh refinement for solid-liquid phase change

    NASA Astrophysics Data System (ADS)

    Huang, Rongzong; Wu, Huiying

    2016-06-01

    A total enthalpy-based lattice Boltzmann (LB) method with adaptive mesh refinement (AMR) is developed in this paper to efficiently simulate solid-liquid phase change problem where variables vary significantly near the phase interface and thus finer grid is required. For the total enthalpy-based LB method, the velocity field is solved by an incompressible LB model with multiple-relaxation-time (MRT) collision scheme, and the temperature field is solved by a total enthalpy-based MRT LB model with the phase interface effects considered and the deviation term eliminated. With a kinetic assumption that the density distribution function for solid phase is at equilibrium state, a volumetric LB scheme is proposed to accurately realize the nonslip velocity condition on the diffusive phase interface and in the solid phase. As compared with the previous schemes, this scheme can avoid nonphysical flow in the solid phase. As for the AMR approach, it is developed based on multiblock grids. An indicator function is introduced to control the adaptive generation of multiblock grids, which can guarantee the existence of overlap area between adjacent blocks for information exchange. Since MRT collision schemes are used, the information exchange is directly carried out in the moment space. Numerical tests are firstly performed to validate the strict satisfaction of the nonslip velocity condition, and then melting problems in a square cavity with different Prandtl numbers and Rayleigh numbers are simulated, which demonstrate that the present method can handle solid-liquid phase change problem with high efficiency and accuracy.

  13. Interaction of SiC particles with moving solid-liquid interface during directional solidification of silicon

    NASA Astrophysics Data System (ADS)

    Friedrich, J.; Reimann, C.; Jauss, T.; Cröll, A.; Sorgenfrei, T.

    2016-08-01

    In this work, the interaction of SiC particles, having sizes of 7 μm to 300 μm, with the moving solid-liquid interface during directional solidification of silicon was experimentally and theoretically investigated. This included both convective and nearly diffusive conditions. In the nearly diffusive regime under microgravity, the particles were incorporated at a lower growth velocity than in the convective regime under 1g conditions. The experimental data were compared to simple theoretical models allowing the calculation of the critical growth velocity for the incorporation of spherical particles in dependence of the particle size. It was found that the theoretical results could qualitatively explain the experimental observations when a proper set of equations for the forces acting on the particle and of the material constants are chosen. It can be concluded that sedimentation of the particles due to gravity seems to play a role only for large particles. On the other hand, melt flow might cause a lift force which would push the particles away from the solid-liquid interface, and thus would result in higher critical growth velocities under convective conditions, e.g. due to buoyancy convection. Therefore, a contribution of the missing lift force under μg conditions could lead to the smaller critical growth velocity for particle incorporation that is observed under microgravity.

  14. Transformation of ferulic acid to vanillin using a fed-batch solid-liquid two-phase partitioning bioreactor.

    PubMed

    Ma, Xiao-kui; Daugulis, Andrew J

    2014-01-01

    Amycolatopsis sp. ATCC 39116 (formerly Streptomyces setonii) has shown promising results in converting ferulic acid (trans-4-hydroxy-3-methoxycinnamic acid; substrate), which can be derived from natural plant wastes, to vanillin (4-hydroxy-3-methoxybenzaldehyde). After exploring the influence of adding vanillin at different times during the growth cycle on cell growth and transformation performance of this strain and demonstrating the inhibitory effect of vanillin, a solid-liquid two-phase partitioning bioreactor (TPPB) system was used as an in situ product removal technique to enhance transformation productivity by this strain. The thermoplastic polymer Hytrel(®) G4078W was found to have superior partitioning capacity for vanillin with a partition coefficient of 12 and a low affinity for the substrate. A 3-L working volume solid-liquid fed-batch TPPB mode, using 300 g Hytrel G4078W as the sequestering phase, produced a final vanillin concentration of 19.5 g/L. The overall productivity of this reactor system was 450 mg/L. h, among the highest reported in literature. Vanillin was easily and quantitatively recovered from the polymers mostly by single stage extraction into methanol or other organic solvents used in food industry, simultaneously regenerating polymer beads for reuse. A polymer-liquid two phase bioreactor was again confirmed to easily outperform single phase systems that feature inhibitory or easily further degraded substrates/products. This enhancement strategy might reasonably be expected in the production of other flavor and fragrance compounds obtained by biotransformations. PMID:24167066

  15. Janus Solid-Liquid Interface Enabling Ultrahigh Charging and Discharging Rate for Advanced Lithium-Ion Batteries.

    PubMed

    Zheng, Jiaxin; Hou, Yuyang; Duan, Yandong; Song, Xiaohe; Wei, Yi; Liu, Tongchao; Hu, Jiangtao; Guo, Hua; Zhuo, Zengqing; Liu, Lili; Chang, Zheng; Wang, Xiaowei; Zherebetskyy, Danylo; Fang, Yanyan; Lin, Yuan; Xu, Kang; Wang, Lin-Wang; Wu, Yuping; Pan, Feng

    2015-09-01

    LiFePO4 has long been held as one of the most promising battery cathode for its high energy storage capacity. Meanwhile, although extensive studies have been conducted on the interfacial chemistries in Li-ion batteries,1-3 little is known on the atomic level about the solid-liquid interface of LiFePO4/electrolyte. Here, we report battery cathode consisted with nanosized LiFePO4 particles in aqueous electrolyte with an high charging and discharging rate of 600 C (3600/600 = 6 s charge time, 1 C = 170 mAh g(-1)) reaching 72 mAh g(-1) energy storage (42% of the theoretical capacity). By contrast, the accessible capacity sharply decreases to 20 mAh g(-1) at 200 C in organic electrolyte. After a comprehensive electrochemistry tests and ab initio calculations of the LiFePO4-H2O and LiFePO4-EC (ethylene carbonate) systems, we identified the transient formation of a Janus hydrated interface in the LiFePO4-H2O system, where the truncated symmetry of solid LiFePO4 surface is compensated by the chemisorbed H2O molecules, forming a half-solid (LiFePO4) and half-liquid (H2O) amphiphilic coordination environment that eases the Li desolvation process near the surface, which makes a fast Li-ion transport across the solid/liquid interfaces possible. PMID:26305572

  16. Growing TiO2 nanowires by solid-liquid-solid mechanism including two factors (Ti and O)

    NASA Astrophysics Data System (ADS)

    Pishekloo, S. Piri; Dariani, R. S.

    2016-04-01

    Identifying the growth factors of nanowires helps in controlling their structure and morphology and determining their optimal growth conditions. This study investigates the effect of titanium substrate in growing TiO2 nanowires (NWs) with evaporation method. It reveals that the titanium in substrate is indeed the main source of growth. Using the substrate as the only source of growth with regulated amount of accessible oxygen in the furnace, NWs with lengths ranging from 1 to 70 µm were obtained. The results of the experiments show that the nanowires' growth is mainly controlled by diffusion of titanium atoms from the substrate through TiO2 grain boundaries and surface diffusion toward NWs' tips rather than adsorption from vapor phase. The solid-liquid-solid mechanism including two factors (Ti and O) is proposed and discussed for growth of TiO2 NWs.

  17. Calculating the role of composition in the anisotropy of solid-liquid interface energy using phase-field-crystal theory

    NASA Astrophysics Data System (ADS)

    Jugdutt, Bernadine A.; Ofori-Opoku, Nana; Provatas, Nikolas

    2015-10-01

    This work uses Ginzburg-Landau theory derived from a recent structural phase-field-crystal model of binary alloys developed by the authors to study the roles of concentration, temperature, and pressure on the interfacial energy anisotropy of a solid-liquid front. It is found that the main contribution to the change in anisotropy with concentration arises from a change in preferred crystallographic orientation controlled by solute-dependent changes in the two-point density correlation function of a binary alloy, a mechanism that leads to such phenomena as solute-induced elastic strain and dislocation-assisted solute clustering. Our results are consistent with experimental observations in recent studies by Rappaz et al. [J. Fife, P. Di Napoli, and M. Rappaz, Metall. Mater. Trans. A 44, 5522 (2013), 10.1007/s11661-013-1912-7]. This is the first PFC work, to our knowledge, to incorporate temperature, pressure, and density into the thermodynamic description of alloys.

  18. Crystal growth kinetics in Lennard-Jones and Weeks-Chandler-Andersen systems along the solid-liquid coexistence line

    NASA Astrophysics Data System (ADS)

    Benjamin, Ronald; Horbach, Jürgen

    2015-07-01

    Kinetics of crystal-growth is investigated along the solid-liquid coexistence line for the (100), (110), and (111) orientations of the Lennard-Jones (LJ) and Weeks-Chandler-Andersen (WCA) fcc crystal-liquid interface, using non-equilibrium molecular dynamics simulations. A slowing down of the growth kinetics along the coexistence line is observed, which is due to the decrease of the melting enthalpy with increasing coexistence temperature and pressure. Other quantities such as the melting pressure and liquid self-diffusion coefficient have a comparatively lesser impact on the kinetic growth coefficient. Growth kinetics of the LJ and WCA potentials become similar at large values of the melting temperature and pressure, when both resemble a purely repulsive soft-sphere potential. Classical models of crystallization from the melt are in reasonable qualitative agreement with our simulation data. Finally, several one-phase empirical melting/freezing rules are studied with respect to their validity along the coexistence line.

  19. Calculating the role of composition in the anisotropy of solid-liquid interface energy using phase-field-crystal theory.

    PubMed

    Jugdutt, Bernadine A; Ofori-Opoku, Nana; Provatas, Nikolas

    2015-10-01

    This work uses Ginzburg-Landau theory derived from a recent structural phase-field-crystal model of binary alloys developed by the authors to study the roles of concentration, temperature, and pressure on the interfacial energy anisotropy of a solid-liquid front. It is found that the main contribution to the change in anisotropy with concentration arises from a change in preferred crystallographic orientation controlled by solute-dependent changes in the two-point density correlation function of a binary alloy, a mechanism that leads to such phenomena as solute-induced elastic strain and dislocation-assisted solute clustering. Our results are consistent with experimental observations in recent studies by Rappaz et al. [J. Fife, P. Di Napoli, and M. Rappaz, Metall. Mater. Trans. A 44, 5522 (2013)]. This is the first PFC work, to our knowledge, to incorporate temperature, pressure, and density into the thermodynamic description of alloys. PMID:26565255

  20. Dynamic formation of a solid-liquid electrolyte interphase and its consequences for hybrid-battery concepts.

    PubMed

    Busche, Martin R; Drossel, Thomas; Leichtweiss, Thomas; Weber, Dominik A; Falk, Mareike; Schneider, Meike; Reich, Maria-Louisa; Sommer, Heino; Adelhelm, Philipp; Janek, Jürgen

    2016-05-01

    The discharging and charging of batteries require ion transfer across phase boundaries. In conventional lithium-ion batteries, Li(+) ions have to cross the liquid electrolyte and only need to pass the electrode interfaces. Future high-energy batteries may need to work as hybrids, and so serially combine a liquid electrolyte and a solid electrolyte to suppress unwanted redox shuttles. This adds new interfaces that might significantly decrease the cycling-rate capability. Here we show that the interface between a typical fast-ion-conducting solid electrolyte and a conventional liquid electrolyte is chemically unstable and forms a resistive solid-liquid electrolyte interphase (SLEI). Insights into the kinetics of this new type of interphase are obtained by impedance studies of a two-chamber cell. The chemistry of the SLEI, its growth with time and the influence of water impurities are examined by state-of-the-art surface analysis and depth profiling. PMID:27102676

  1. Dynamic formation of a solid-liquid electrolyte interphase and its consequences for hybrid-battery concepts

    NASA Astrophysics Data System (ADS)

    Busche, Martin R.; Drossel, Thomas; Leichtweiss, Thomas; Weber, Dominik A.; Falk, Mareike; Schneider, Meike; Reich, Maria-Louisa; Sommer, Heino; Adelhelm, Philipp; Janek, Jürgen

    2016-05-01

    The discharging and charging of batteries require ion transfer across phase boundaries. In conventional lithium-ion batteries, Li+ ions have to cross the liquid electrolyte and only need to pass the electrode interfaces. Future high-energy batteries may need to work as hybrids, and so serially combine a liquid electrolyte and a solid electrolyte to suppress unwanted redox shuttles. This adds new interfaces that might significantly decrease the cycling-rate capability. Here we show that the interface between a typical fast-ion-conducting solid electrolyte and a conventional liquid electrolyte is chemically unstable and forms a resistive solid-liquid electrolyte interphase (SLEI). Insights into the kinetics of this new type of interphase are obtained by impedance studies of a two-chamber cell. The chemistry of the SLEI, its growth with time and the influence of water impurities are examined by state-of-the-art surface analysis and depth profiling.

  2. Free-Surface Optical Scattering as an Indicator of the Shock-Induced Solid-Liquid Phase Transition in Tin

    SciTech Connect

    Stevens, G. D.; Lutz, S. S.; Marshall, B. R.; Turley, W. D.; Veeser, L. R.; Furlanetto, M. R.; Hixson, R. S.; Holtkamp, D. B.; Jensen, B. J.; Rigg, P. A.; Wilke, M. D.

    2008-07-01

    When highly polished metal surfaces melt upon release after shock loading, they exhibit features that suggest significant surface changes accompany the phase transition. The reflection of light from such surfaces changes from specular (pre-shock) to diffuse upon melting. A familiar manifestation of this phenomenon is the loss of signal light in VISAR measurements, which occurs at pressures high enough to melt the free surface. Unlike many other potential material phase-sensitive diagnostics (e.g., reflectometry, conductivity) that show relatively small (1%–10%) changes, the specularity of reflection provides a more sensitive and definitive indication of the solid-liquid phase transition. Data will be presented that support the hypothesis that specularity changes indicate melt in a way that can be measured easily and unambiguously.

  3. The use of hard- and soft-modelling to predict radiostrontium solid-liquid distribution coefficients in soils.

    PubMed

    Gil-García, C J; Rigol, A; Vidal, M

    2011-11-01

    The solid-liquid distribution coefficient (K(d)) is the parameter that governs the incorporation of contaminants in soils. Its estimation allows the prediction of the fate of contaminants in the short- and long-term after a contamination event. Here, the K(d) of radiostrontium (K(d)(Sr)), a radionuclide of significant environmental interest, was predicted by hard models, which are based on knowledge of the mechanisms governing its sorption, and by soft models based on Partial Least Squares (PLS), using a large data set with the main soil parameters. The two approaches were tested and compared for 30 soils in Spain. Correlations between the predicted and experimental values of K(d)(Sr) obtained using hard- and soft-modelling showed slopes close to 1 and regression coefficients higher than 0.95, which confirms that both approaches are able to obtain satisfactory estimates for K(d)(Sr) from soil parameters. PMID:21890173

  4. Three-dimensional atomic force microscopy mapping at the solid-liquid interface with fast and flexible data acquisition

    NASA Astrophysics Data System (ADS)

    Söngen, Hagen; Nalbach, Martin; Adam, Holger; Kühnle, Angelika

    2016-06-01

    We present the implementation of a three-dimensional mapping routine for probing solid-liquid interfaces using frequency modulation atomic force microscopy. Our implementation enables fast and flexible data acquisition of up to 20 channels simultaneously. The acquired data can be directly synchronized with commercial atomic force microscope controllers, making our routine easily extendable for related techniques that require additional data channels, e.g., Kelvin probe force microscopy. Moreover, the closest approach of the tip to the sample is limited by a user-defined threshold, providing the possibility to prevent potential damage to the tip. The performance of our setup is demonstrated by visualizing the hydration structure above the calcite (10.4) surface in water.

  5. Detection of different oxidation states of individual manganese porphyrins during their reaction with oxygen at a solid/liquid interface

    NASA Astrophysics Data System (ADS)

    den Boer, Duncan; Li, Min; Habets, Thomas; Iavicoli, Patrizia; Rowan, Alan E.; Nolte, Roeland J. M.; Speller, Sylvia; Amabilino, David B.; de Feyter, Steven; Elemans, Johannes A. A. W.

    2013-07-01

    Manganese porphyrins have been extensively investigated as model systems for the natural enzyme cytochrome P450 and as synthetic oxidation catalysts. Here, we report single-molecule studies of the multistep reaction of manganese porphyrins with molecular oxygen at a solid/liquid interface, using a scanning tunnelling microscope (STM) under environmental control. The high lateral resolution of the STM, in combination with its sensitivity to subtle differences in the electronic properties of molecules, allowed the detection of at least four distinct reaction species. Real-space and real-time imaging of reaction dynamics enabled the observation of active sites, immobile on the experimental timescale. Conversions between the different species could be tuned by the composition of the atmosphere (argon, air or oxygen) and the surface bias voltage. By means of extensive comparison of the results to those obtained by analogous solution-based chemistry, we assigned the observed species to the starting compound, reaction intermediates and products.

  6. Solid-liquid boundaries in iron-rich alloys and the age of the Earth's inner core

    NASA Astrophysics Data System (ADS)

    Li, J.; Chen, B.; Gao, L.

    2006-05-01

    Melting and solidification cause major chemical differentiation in the Earth. As the Earth cools, the liquid core solidifies from the center and the inner core grows at the expense of the outer core. The timing of the onset of core solidification remains poorly constrained. Labrosse et al. (2001) estimated the age of the Earth's inner core based on energy budget considerations. In their analysis, the latent heat and gravitational energy are calculated according to dislocation melting theory. We have conducted melting experiments on pure iron and an iron-sulfur alloy containing 15 at.% sulfur, in order to determine the effect of pressure on the Clapeyron slopes of the solid-liquid boundaries. Our results allow a critical examination of the energy estimates, hence the age of the inner core. The implications for the budget of radioactive elements will be discussed.

  7. Resonant anomalous x-ray reflectivity as a probe of ion adsorption at solid-liquid interfaces.

    SciTech Connect

    Fenter, P.; Park, C.; Nagy, K. L.; Sturchio, N. C.; Chemistry; Univ. of Illinois at Chicago

    2007-05-23

    We discuss new opportunities to understand processes at the solid-liquid interface using resonant anomalous X-ray reflectivity (RAXR). This approach is illustrated by determination of element-specific density profiles at mica surfaces in aqueous electrolyte solutions containing Rb{sup +} and Sr{sup 2+}. The total interfacial electron density profile is determined by specular reflectivity (i.e., reflected intensity vs. momentum transfer, q, at an energy, E, far from any characteristic absorption edge). RAXR spectra (i.e., intensity vs. E at fixed q) reveal element-specific ion distributions. Key differences in the interaction of Rb{sup +} and Sr{sup 2+} with mica are observed using resonant anomalous X-ray reflectivity: Rb{sup +} adsorbs in a partially hydrated state, but Sr{sup 2+} adsorbs in both fully and partially hydrated states.

  8. Inferences about radionuclide mobility in soils based on the solid/liquid partition coefficients and soil properties.

    PubMed

    Sohlenius, Gustav; Saetre, Peter; Nordén, Sara; Grolander, Sara; Sheppard, Steve

    2013-05-01

    To assist transport modeling in assessments of the radiological impact of a geological repository for radioactive wastes, the mobility of various elements was studied in arable and wetland soils in the Forsmark region, Sweden. Pore water and total element contents were determined for five types of unconsolidated deposits (regolith), spanning a wide range of soil properties with respect to pH and organic matter content. Two soil depths were sampled to capture element mobility in regolith layers affected and unaffected by soil-forming processes. The solid/liquid partition coefficients (K d values) for most elements varied significantly among regolith types. For most elements, the observed variations in K d values could be explained by variations in soil properties. For many elements, mobility increased with decreasing soil pH. The results provide a significant addition of data on radionuclide retention in soils, taking account of soil properties and processes. PMID:23619799

  9. Solid-liquid-solid process for forming free-standing gold nanowhisker superlattice by interfering femtosecond laser irradiation

    NASA Astrophysics Data System (ADS)

    Nakata, Y.; Miyanaga, N.; Momoo, K.; Hiromoto, T.

    2013-06-01

    One-dimensional nanomaterial superlattices are fundamental components in plasmonics, nanophotonics, and nanoelectronics. Bottom-up techniques such as vapour-liquid-solid (VLS) and chemosynthesis have been used to fabricate the structure but are nonoptimal for controlling alignment and size. Here we report the fabrication of gold nanowhisker superlattice, based on a novel mechanism termed solid-liquid-solid (SLS). An interfering femtosecond laser pulse induces fluid flows of nanosize gold, which is followed by droplets pinching off from them and freezing of a free-standing nanowhisker superlattice fixed on a substrate. The shape is defined by liquid motion and not by crystallographic growth although its structure is polycrystalline. The smallest curvature radius of its vertex was 3.4 nm, which is one-half of the smallest nanorods fabricated by chemosynthesis. SLS process is a superior alternative to sequential bottom-up processes involving catalyst fabrication, bottom-up synthesis, purification, alignment, stabilization, and preservation.

  10. Rapid Carbonation for Calcite from a Solid-Liquid-Gas System with an Imidazolium-Based Ionic Liquid

    PubMed Central

    Ibrahim, Abdul-Rauf; Vuningoma, Jean Bosco; Huang, Yan; Wang, Hongtao; Li, Jun

    2014-01-01

    Aqueous carbonation of Ca(OH)2 is a complex process that produces calcite with scalenohedral calcite phases and characterized by inadequate carbonate species for effective carbonation due to the poor dissolution of CO2 in water. Consequently, we report a solid-liquid-gas carbonation system with an ionic liquid (IL), 1-butyl-3-methylimidazolium bromide, in view of enhancing the reaction of CO2 with Ca(OH)2. The use of the IL increased the solubility of CO2 in the aqueous environment and enhanced the transport of the reactive species (Ca2+ and CO32−) and products. The presence of the IL also avoided the formation of the CaCO3 protective and passivation layer and ensured high carbonation yields, as well as the production of stoichiometric rhombohedral calcite phases in a short time. PMID:24968273

  11. L'Anse Aux Meadows, Newfoundland

    NASA Technical Reports Server (NTRS)

    2008-01-01

    L'Anse aux Meadows is a site on the northernmost tip of the island of Newfoundland, located in the Province of Newfoundland and Labrador, Canada, where the remains of a Viking village were discovered in 1960 by the Norwegians Helge and Anne Ingstad. The only authenticated Viking settlement in North America outside Greenland, it was the site of a multi-year archaeological dig that found dwellings, tools and implements that verified its time frame. The settlement, dating more than five hundred years before Christopher Columbus, contains the earliest European structures in North America. Named a World Heritage site by UNESCO, it is thought by many to be the semi-legendary 'Vinland' settlement of explorer Leif Ericson around AD 1000. The settlement at L'Anse aux Meadows consisted of at least eight buildings, including a forge and smelter, and a lumber yard that supported a shipyard. The largest house measured 28.8 by 15.6 m and consisted of several rooms. Sewing and knitting tools found at the site indicate women were present at L'Anse aux Meadows

    The image was acquired on September 14, 2007, covers an area of 14.2 x 14.6 km, and is located at 51.5 degrees north latitude, 55.6 degrees west longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  12. Real-time observation of the solid-liquid-vapor dissolution of individual tin(IV) oxide nanowires.

    PubMed

    Hudak, Bethany M; Chang, Yao-Jen; Yu, Lei; Li, Guohua; Edwards, Danielle N; Guiton, Beth S

    2014-06-24

    The well-known vapor-liquid-solid (VLS) mechanism results in high-purity, single-crystalline wires with few defects and controllable diameters, and is the method of choice for the growth of nanowires for a vast array of nanoelectronic devices. It is of utmost importance, therefore, to understand how such wires interact with metallic interconnects-an understanding which relies on comprehensive knowledge of the initial growth process, in which a crystalline wire is ejected from a metallic particle. Though ubiquitous, even in the case of single elemental nanowires the VLS mechanism is complicated by competing processes at multiple heterogeneous interfaces, and despite decades of study, there are still aspects of the mechanism which are not well understood. Recent breakthroughs in studying the mechanism and kinetics of VLS growth have been strongly aided by the use of in situ techniques, and would have been impossible through other means. As well as several systematic studies of nanowire growth, reports which focus on the role and the nature of the catalyst tip reveal that the stability of the droplet is a crucial factor in determining nanowire morphology and crystallinity. Additionally, a reverse of the VLS process dubbed solid-liquid-vapor (SLV) has been found to result in the formation of cavities, or "negative nanowires". Here, we present a series of heating studies conducted in situ in the transmission electron microscope (TEM), in which we observe the complete dissolution of metal oxide nanowires into the metal catalyst particles at their tips. We are able to consistently explain our observations using a solid-liquid-vapor (SLV) type mechanism in which both evaporation at the liquid-vapor interface and adhesion of the catalyst droplet to the substrate surface contribute to the overall rate. PMID:24818706

  13. Numerical determination of the interfacial energy and nucleation barrier of curved solid-liquid interfaces in binary systems.

    PubMed

    Kundin, Julia; Choudhary, Muhammad Ajmal

    2016-07-01

    The phase-field crystal (PFC) technique is a widely used approach for modeling crystal growth phenomena with atomistic resolution on mesoscopic time scales. We use a two-dimensional PFC model for a binary system based on the work of Elder et al. [Phys. Rev. B 75, 064107 (2007)PRBMDO1098-012110.1103/PhysRevB.75.064107] to study the effect of the curved, diffuse solid-liquid interface on the interfacial energy as well as the nucleation barrier. The calculation of the interfacial energy and the nucleation barrier certainly depends on the proper definition of the solid-liquid dividing surface and the corresponding nucleus size. We define the position of the sharp interface at which the interfacial energy is to be evaluated by using the concept of equimolar dividing surface (r^{e}) and the minimization of the interfacial energy (r^{s}). The comparison of the results based on both radii shows that the difference r^{e}-r^{s} is always positive and has a limit for large cluster sizes which is comparable to the Tolman length. Furthermore, we found the real nucleation barrier for small cluster sizes, which is defined as a function of the radius r^{s}, and compared it with the classical nucleation theory. The simulation results also show that the extracted interfacial energy as function of both radii is independent of system size, and this dependence can be reasonably described by the nonclassical Tolman formula with a positive Tolman length. PMID:27575196

  14. Effect of graphene layer thickness and mechanical compliance on interfacial heat flow and thermal conduction in solid-liquid phase change materials.

    PubMed

    Warzoha, Ronald J; Fleischer, Amy S

    2014-08-13

    Solid-liquid phase change materials (PCMs) are attractive candidates for thermal energy storage and electronics cooling applications but have limited applicability in state-of-the-art technologies due to their low intrinsic thermal conductivities. Recent efforts to incorporate graphene and multilayer graphene into PCMs have led to the development of thermal energy storage materials with remarkable values of bulk thermal conductivity. However, the full potential of graphene as a filler material for the thermal enhancement of PCMs remains unrealized, largely due to an incomplete understanding of the physical mechanisms that govern thermal transport within graphene-based nanocomposites. In this work, we show that the number of graphene layers (n) within an individual graphene nanoparticle has a significant effect on the bulk thermal conductivity of an organic PCM. Results indicate that the bulk thermal conductivity of PCMs can be tuned by over an order of magnitude simply by adjusting the number of graphene layers (n) from n = 3 to 44. Using scanning electron microscopy in tandem with nanoscale analytical techniques, the physical mechanisms that govern heat flow within a graphene nanocomposite PCM are found to be nearly independent of the intrinsic thermal conductivity of the graphene nanoparticle itself and are instead found to be dependent on the mechanical compliance of the graphene nanoparticles. These findings are critical for the design and development of PCMs that are capable of cooling next-generation electronics and storing heat effectively in medium-to-large-scale energy systems, including solar-thermal power plants and building heating and cooling systems. PMID:24983698

  15. Pre-Service Primary Science Teachers' Understandings of the Effect of Temperature and Pressure on Solid-Liquid Phase Transition of Water

    ERIC Educational Resources Information Center

    Yalcin, Fatma Aggul

    2012-01-01

    The aim of this study was to explore pre-service primary teachers' understandings of the effect of temperature and pressure on the solid-liquid phase transition of water. In the study a survey approach was used, and the sample consisted of one-hundred and three, third year pre-service primary science teachers. As a tool for data collection, a test…

  16. SOLID-LIQUID PHASE TRANSFER CATALYZED SYNTHESIS OF CINNAMYL ACETATE-KINETICS AND ANALYSIS OF FACTORS AFFECTING THE REACTION IN A BATCH REACTOR

    EPA Science Inventory

    The use of solid-liquid phase transfer catalysis has an advantage of carrying out reaction between two immiscible substrates, one in solid phase and the other in liquid phase, with high selectivity and at relatively low temperatures. In this study we investigated the synthesis ci...

  17. Surface composition variation and high-vacuum performance of DLC/ILs solid-liquid lubricating coatings: Influence of space irradiation

    NASA Astrophysics Data System (ADS)

    Liu, Xiufang; Wang, Liping; Pu, Jibin; Xue, Qunji

    2012-08-01

    In this paper, we fabricated a DLC/ionic liquid (DLC/ILs) solid-liquid lubricating coating and investigated the effect of atomic oxygen (AO), ultraviolet (UV), proton and electron irradiations on composition, structure, morphology and tribological properties of the DLC/ILs solid-liquid lubricating coatings. A ground-based simulation facility was employed to carry out the irradiation experiments. X-ray photoelectron spectroscope (XPS), Raman spectra, and Fourier Transform Infrared Spectroscopy (FTIR) were used to analyzed the structure and composition changes of DLC film and IL lubricant before and after irradiations. The tribological behavior of the DLC/ILs solid-liquid lubricating coating before and after irradiations was investigated by a vacuum tribometer with the pressure of 10-5 Pa. The experimental results revealed that irradiations induced the structural changes, including oxidation, bond break and crosslinking reactions of DLC film and IL lubricant. The damage of proton and AO irradiations to lubricating materials were the most serious, and UV irradiation was the slightest. After irradiations, the friction coefficient of the solid-liquid lubricating coatings decreased (except for AO irradiation), but the disc wear rate increased compared with non-irradiation coatings.

  18. USDA-ARS research update: Improved solid-liquid separation using polymers in flushing systems and new technology to recover the ammonia from covered lagoons

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Part 1: Improved method for recovery of organic solids from diluted swine manure: Solid-liquid separation of the raw manure increases the capacity of decision making and opportunities for treatment. The high-rate separation up-front using flocculants allows recovery of most of the organic compounds,...

  19. Solid-liquid phase coexistence of alkali nitrates from molecular dynamics simulations.

    SciTech Connect

    Jayaraman, Saivenkataraman

    2010-03-01

    Alkali nitrate eutectic mixtures are finding application as industrial heat transfer fluids in concentrated solar power generation systems. An important property for such applications is the melting point, or phase coexistence temperature. We have computed melting points for lithium, sodium and potassium nitrate from molecular dynamics simulations using a recently developed method, which uses thermodynamic integration to compute the free energy difference between the solid and liquid phases. The computed melting point for NaNO3 was within 15K of its experimental value, while for LiNO3 and KNO3, the computed melting points were within 100K of the experimental values [4]. We are currently extending the approach to calculate melting temperatures for binary mixtures of lithium and sodium nitrate.

  20. Communication: Thermal rectification in liquids by manipulating the solid-liquid interface.

    PubMed

    Murad, Sohail; Puri, Ishwar K

    2012-08-28

    Thermal rectification, the origin of which lies in modifying the thermal resistance in a nonlinear manner, could significantly improve the thermal management of a wide range of nano-devices (both electronic and thermoelectric), thereby improving their efficiencies. Since rectification requires a material to be inhomogeneous, it has been typically associated with solids. However, the structure of solids is relatively difficult to manipulate, which makes the tuning of thermal rectification devices challenging. Since liquids are more amenable to tuning, this could open up new applications for thermal rectification. We use molecular dynamics simulations to demonstrate thermal rectification using liquid water. This is accomplished by creating an inhomogeneous water phase, either by changing the morphology of the surface in contact with the liquid or by imposing an arbitrary external force, which in practice could be through an electric or magnetic field. Our system consists of a bulk fluid that is confined in a reservoir that is bounded by two walls, one hot and the other cold. The interfacial (Kapitza) thermal resistance at the solid-fluid interface and the density gradient of the bulk fluid both influence the magnitude of the thermal rectification. However, we find that the role of the interfacial resistance is more prominent than the application of an external force on the bulk fluid. PMID:22938211

  1. Collaborateurs aux lignes directrices en soins primaires

    PubMed Central

    Allan, G. Michael; Kraut, Roni; Crawshay, Aven; Korownyk, Christina; Vandermeer, Ben; Kolber, Michael R.

    2015-01-01

    Résumé Objectif Déterminer la profession des collaborateurs scientifiques aux lignes directrices, les variables associées aux différences de participation des collaborateurs et si oui ou non les lignes directrices en soins primaires fournissent un énoncé sur les conflits d’intérêts. Type d’étude Analyse rétrospective des lignes directrices en soins primaires affichées sur le site web de l’Association médicale canadienne. Deux extracteurs de données indépendants ont examiné les lignes directrices et ont extrait les données pertinentes. Contexte Canada Principaux paramètres à l’étude Commanditaires des lignes directrices, territoire (national ou provincial) visé par les lignes directrices, profession des collaborateurs scientifiques aux lignes directrices et énoncés de conflits d’intérêts rapportés dans les lignes directrices. Résultats Sur les 296 lignes directrices de pratique clinique trouvées dans la section de la médecine familiale de l’Infobanque AMC, 65 apparaissaient en double et 35 se rapportaient de façon limitée à la médecine familiale. Vingt ne fournissaient aucune information sur les collaborateurs scientifiques, ce qui laissait 176 lignes directrices propices à l’analyse. Au total, il y avait 2495 collaborateurs (auteurs et membres de comité) : 1343 (53,8 %) spécialistes autres que des médecins de famille, 423 (17,0 %) médecins de famille, 141 (5,7 %) infirmières, 75 (3,0 %) pharmaciens, 269 (10,8 %) autres cliniciens, 203 (8,1 %) scientifiques non cliniciens et 41 (1,6 %) collaborateurs de profession inconnue. La proportion des collaborateurs de ces professions différait significativement entre les lignes directrices nationales et provinciales, de même qu’entre les lignes directrices financées par l’industrie et celles qui ne l’étaient pas (p < 0,001 dans les 2 cas). Dans le cas des lignes directrices de pratique clinique provinciales, 30,8 % des collaborateurs étaient des médecins de

  2. Direct imaging of complex nano- to microscale interfaces involving solid, liquid, and gas phases.

    PubMed

    Rykaczewski, Konrad; Landin, Trevan; Walker, Marlon L; Scott, John Henry J; Varanasi, Kripa K

    2012-10-23

    Surfaces with special wetting properties not only can efficiently repel or attract liquids such as water and oils but also can prevent formation of biofilms, ice, and clathrate hydrates. Predicting the wetting properties of these special surfaces requires detailed knowledge of the composition and geometry of the interfacial region between the droplet and the underlying substrate. In this work we introduce a 3D quantitative method for direct nanoscale visualization of such interfaces. Specifically, we demonstrate direct nano- to microscale imaging of complex fluidic interfaces using cryostabilization in combination with cryogenic focused ion beam milling and SEM imaging. We show that application of this method yields quantitative information about the interfacial geometry of water condensate on superhydrophilic, superhydrophobic, and lubricant-impregnated surfaces with previously unattainable nanoscale resolution. This type of information is crucial to a fundamental understanding as well as the design of surfaces with special wetting properties. PMID:23020195

  3. Interaction mechanism of in-situ nano-TiN-AlN particles and solid/liquid interface during solidification.

    PubMed

    Cui, Chunxiang; Li, Yanchun; Shen, Yutian; Sun, Jibing; Wang, Ru

    2003-10-01

    This paper deals with the interaction mechanism between in situ nanometer-grade TiN-AlN particles and the solid/liquid (S/L) interface during the solidification of an in situ TiN-AlN/Al composite. According to the setting of a force balance for the particles in front of the S/L interface during solidification, F = F(buoyant) + F(repulsive) + F(viscous). We obtained the relationship between the critical cooling velocity of the liquid composite, Vr, and the size of the ceramic particle, rp. By this relationship formula, we can know that the S/L interface engulfs particles or pushes them to the crystal grain boundary during the solidification of a TiN-AlN/Al composite. It is found that Vr is proportional to the radius of ceramic particles by transmission electron microscope (TEM) observation. The TEM test indicates that the smaller the particle is, the more easily the S/L interface engulfs particles. PMID:14733152

  4. Toluene biodegradation in a solid/liquid system involving immobilized activated sludge and silicone oil as pollutant reservoir.

    PubMed

    Diz Castro, Manuel; Gómez-Díaz, Diego; Amrane, Abdeltif; Couvert, Annabelle

    2015-01-01

    A solid/liquid system involving activated sludge immobilized in an agar medium and a non-aqueous phase liquid containing the target pollutant has been considered to treat a model hydrophobic volatile organic compound, toluene. The positive impact of the use of a multiphase bioreactor is that the organic phase constitutes a pollutant reservoir and also helps to overcome possible pollutant toxicity. In addition and to overcome the drawbacks of the use of a solid organic phase (high pressure drop and low mass transfer) instead of a liquid organic phase, the considered solid phase was the aqueous. Consequently, silicone oil (polydimethylsiloxane) which showed its relevance for implementation in multiphase bioreactors was used. Promising results were observed from the analysis of toluene in the gaseous phase; for an initial amount of 2 g L(-1) related to the organic phase, a v/v ratio of 0.5 of the organic phase to the aqueous agar phase, total toluene consumption was observed in about 9 days, leading to a global biodegradation rate of approximately 3.1 mg L(-1) h(-1), namely in the range of values previously observed in liquid/liquid systems. PMID:25187471

  5. Arrhenian and Non-Arrhenian Temperature Dependent Relaxation Time Development in the Solid-Liquid Transition Area of Amorphous Bodies

    NASA Astrophysics Data System (ADS)

    Hlaváček, Bořivoj; Drašar, Čestmír; Kalendová, Andréa; Menc, Pavel; Veselý, David

    The temperature-dependent changes of molecular and sub-molecular motions are studied in amorphous substances. The solid and liquid phases of amorphous bodies are characterized at the micro-level by two types of oscillators, linear and non-linear. It is accepted that an amorphous liquid is formed by domains that group the linear oscillators into the form of icebergs. The serial connection of the viscoelastic elements are arranged inside of these icebergs. The size of the linear connection within the domains is characterized by the number "n", which increases during the cooling process. The linear viscoelastic behavior of the individual serial connections is connected to the individual relaxation processes α, β, and γ. Only the "alpha" process exhibits growth of "n" to infinity on cooling. Therefore, the corresponding relaxation time, τα, for the infinite chain of "n" elements (Voigt or Maxwell elements) can also reach infinity as the material transforms to a glassy state. In contrast to the "alpha" process, the β and γ processes are limited in growth for serial connections in a chain structure. Therefore, the relaxation times for the β and γ processes, τβ and τγ, will only follow the temperature dependence of the sample viscosity on cooling, which is, of course, Arrhenian. We discuss the role of non-linear oscillators in the solid-liquid transition in relation to Brownian motion.

  6. The research on particle trajectory of solid-liquid two-phase flow and erosion predicting in screw centrifugal pump

    NASA Astrophysics Data System (ADS)

    Shen, Z. J.; Li, R. N.; Han, W.; Zhao, W. G.; Wang, X. H.

    2016-05-01

    Use the Discrete Phase Model (DPM) based on Euler-Lagrange method, the internal flow field of screw centrifugal pump was simulated by computational fluid dynamics(CFD) code when transmission medium is solid-liquid two phase flow with large-size particles. The research of liquid phase is under the Euler coordinate system while the solid phase is under the Lagrange coordinate system. The energy change, trajectory characteristic of solid phase particle and its erosion damage rule of solid-phase particle in whole computational domain is analyzed with different density, partical size(d=0.05mm, d=0.2mm, d=2mm) and solid volume fraction(Cv=3%, Cv=5%, Cv=7%).The result shows that within a given diameter range, the low density fine particles trajectory are longer, more collision times with flow passage components, more energy loss and the erosion parts are relatively uniform, but particles which are large-size diameter and high density has a big collision angle with the surface of impeller and volute, even the area of impact and abrasion are quite focus, and easy to be transported. particles will impact with the head of impeller when it enter into impeller domain, the erosion mainly occurs on the work side of impeller.

  7. Structural ordering at solid-liquid interfaces in Al-Sm system: A molecular-dynamics study

    DOE PAGESBeta

    Sun, Yang; Zhang, Feng; Ye, Zhuo; Ding, Zejun; Mendelev, Mikhail I.; Kramer, Matthew J.; Wang, Cai -Zhuang; Ho, Kai -Ming

    2016-07-12

    The structural ordering at solid-liquid interfaces far from equilibrium is studied with molecular dynamics simulations for the Al-Sm system. Using the van-Hove self-correlation function as the criterion to identify attachment/detachment events that occur at the interface, we are able to determine the time-dependent interface position, and characterize the detailed interfacial structure ordering surrounding the attached atoms. For the interface between an undercooled Al90Sm10 liquid and a metastable cubic structure, the solid induces the crystalline order of the cubic phase in the liquid layers, promoting the continuous growth of the crystal phase. When the same liquid is put in contact withmore » f.c.c. Al, Sm from the liquid can still attach to the solid interface despite its insolubility in the Al lattice. Non-f.c.c. order is revealed surrounding the attached Sm atoms. Lastly, we show that the local structure ordering at interface is highly correlated to solid packing and liquid ordering.« less

  8. Influences of solid/liquid boundary layer thickness and tilting angle on zone-refinement of germanium crystals

    NASA Astrophysics Data System (ADS)

    Yang, Gang; Guan, Yutong; Mei, Hao; Wang, Guojian; Mei, Dongming

    In zone-refining of metals, solid/liquid (S/L) boundary layer thickness has an influence on segregation coefficient of impurity atoms. Additionally, the segregation of impurity elements during zone refining can be maximized by adjusting the zone refinement tube with a proper angle. In this paper, we report the influences of S/L boundary layer thickness on the segregation coefficients of boron, phosphor, aluminum and gallium, which have been identified as four main impurities in germanium crystal by Photothermal Ionization Spectroscopy (PTIS). The thickness of S/L boundary layer was found by using a well-known model to fit the experimental data. The optimized segregation coefficients have been used to calculate the impurity distribution along the purified ingot. In addition, we have also optimized the tilting angle of the germanium ingot to investigate the impact on the segregation. This work is supported by DOE grant DE-FG02-10ER46709 and the state of South Dakota.

  9. Effect of many-body interactions on the solid-liquid phase behavior of charge-stabilized colloidal suspensions

    NASA Astrophysics Data System (ADS)

    Dobnikar, J.; Rzehak, R.; von Grünberg, H. H.

    2003-03-01

    The solid-liquid phase diagram of charge-stabilized colloidal suspensions has been calculated using a technique that combines a continuous Poisson-Boltzmann description for the microscopic electrolyte ions with a molecular-dynamics simulation for the macroionic colloidal spheres. While correlations between the microions are neglected in this approach, many-body interactions between the colloids, mediated by the screening ionic fluid between them, are fully included. The Lindemann criterion has been used to determine the solid-to-liquid transition temperature in a colloidal system at a relatively high colloid volume fraction where many-body interactions are expected to be strong. With a view to the Derjaguin-Landau-Verwey-Overbeek theory predicting that colloids interact via Yukawa pair potentials, we compare our results with the phase diagram of a simple Yukawa liquid. We find an agreement under high-salt conditions, but considerable differences at low ionic strength. Using effective force calculations and data from molecular-dynamics simulations with simple model potentials, we further demonstrate that these differences are due to many-body interactions.

  10. Study on solid-liquid two-phase unsteady flow characteristics with different flow rates in screw centrifugal pump

    NASA Astrophysics Data System (ADS)

    Li, R. N.; Y Wang, H.; Han, W.; Ma, W.; Shen, Z. J.

    2013-12-01

    The screw centrifugal pump is used as an object, and the unsteady numerical simulation of solid-liquid two-phase flow is carried out under different flow rate conditions in one circle by choosing the two-phase flow of sand and water as medium, using the software FLUENT based on the URANS equations, combining with sliding mesh method, and choosing the Mixture multiphase flow model and the SIMPLE algorithm. The results show that, with the flow rate increasing, the change trends for the pressure on volute outlet are almost constant, the fluctuation trends of the impeller axial force have a little change, the pressure and the axial force turn to decrease on the whole, the radial force gradually increases when the impeller maximum radius passes by half a cycle near the volute outlet, and the radial force gradually decreases when the maximum radius passes by the other half a cycle in a rotation cycle. The distributions of the solid particles are very uneven under a small flow rate condition on the face. The solid particles under a big flow rate condition are distributed more evenly than the ones under a small flow rate condition on the back. The theoretical basis and reference are provided for improving its working performance.

  11. Using scanning electrochemical microscopy to probe chemistry at the solid-liquid interface in chemically amplified immersion lithography

    NASA Astrophysics Data System (ADS)

    LeSuer, Robert J.; Fan, Fu-Ren F.; Bard, Allen J.; Taylor, J. Christopher; Tsiartas, Pavlos; Willson, Grant; Conley, Willard E.; Feit, Gene; Kunz, Roderick R.

    2004-05-01

    Three modes of scanning electrochemical microscopy (SECM) - voltammetry, pH, and conductivity - have been used to better understand the chemistry at, and diffusion through, the solid/liquid interface formed between a resist film and water in 193 nm immersion lithography. Emphasis has been placed on investigating the photoacid generator (PAG), triphenylsulfonium perfluorobutanesulfonate, and the corresponding photoacid. The reduction of triphenylsulfonium at a hemispherical Hg microelectrode was monitored using square wave voltammetry to detect trace amounts of the PAG leaching from the surface. pH measurements at a 100 μm diameter Sb microelectrode show the formation of acid in the water layer above a resist upon exposure with UV irradiation. Bipolar conductance measurements at a 100 μm Pt tip positioned 100 μm from the surface indicate that the conductivity of the solution during illumination is dependent upon the percentage of PAG in the film. Liquid chromatography mass spectrometric analysis of water samples in contact with resist films has been used to quantify the amounts (< 10 ng/cm2) of PAG leaching from the film in the dark which occurs within the first 30 seconds of contact time. Washing the film removes approximately 80% of the total leachable PAG.

  12. Solid-liquid interfacial energy of neopentylglycol solid solution in equilibrium with neopentylglycol-(D) camphor eutectic liquid

    NASA Astrophysics Data System (ADS)

    Bayram, Ü.; Aksöz, S.; Maraşlı, N.

    2012-01-01

    The grain boundary groove shapes for equilibrated solid neopentylglycol (NPG) solution (NPG-3 mol% D-camphor) in equilibrium with the NPG-DC eutectic liquid (NPG-36.1 mol% D-camphor) have been directly observed using a horizontal linear temperature gradient apparatus. From the observed grain boundary groove shapes, the Gibbs-Thomson coefficient ( Г), solid-liquid interfacial energy ( σSL) of NPG solid solution have been determined to be (7.5±0.7)×10 -8 K m and (8.1±1.2)×10 -3 J m -2, respectively. The Gibbs-Thomson coefficient versus TmΩ1/3, where Ω is the volume per atom was also plotted by linear regression for some organic transparent materials and the average value of coefficient ( τ) for nonmetallic materials was obtained to be 0.32 from graph of the Gibbs-Thomson coefficient versus TmΩ1/3. The grain boundary energy of solid NPG solution phase has been determined to be (14.6±2.3)×10 -3 J m -2 from the observed grain boundary groove shapes. The ratio of thermal conductivity of equilibrated eutectic liquid to thermal conductivity of solid NPG solution was also measured to be 0.80.

  13. Solid-Liquid Interfacial Energy of Solid Succinonitrile in Equilibrium with Succinonitrile-(D)Camphor-Aminomethylpropanediol Eutectic Liquid

    NASA Astrophysics Data System (ADS)

    Ata, Pınar; Karamazı, Yasin; Bayram, Ümit; Aksöz, Sezen; Keşlioğlu, Kazım; Maraşlı, Necmettin

    2016-01-01

    The grain boundary groove shapes for equilibrated solid SCN in equilibrium with the eutectic liquid SCN-15.6 mol% DC-2.1 mol% AMPD have been directly observed by using a horizontal linear temperature gradient apparatus. The ratio of the thermal conductivity of the equilibrated liquid to the thermal conductivity of solid SCN has also been determined to be 0.89. From the observed grain boundary groove shapes and measured thermal conductivity ratio, the Gibbs-Thomson coefficient ({{\\varGamma }}), solid-liquid interfacial energy (σ _{SL}), and the grain boundary energy (σ _{gb}) have been determined to be (5.43 ± 0.54)× 10^{-8} K{\\cdot } m, (8.53 ± 1.28) × 10^{-3} J {\\cdot } m^{-2}, and (13.36 ± 2.14) × 10^{-3} J{\\cdot } m^{-2}, respectively, for equilibrated solid SCN in equilibrium with the eutectic liquid (SCN-15.6 mol% DC-2.1 mol% AMPD).

  14. Thermodynamic and rheological properties of solid-liquid systems in coal processing. Final technical report

    SciTech Connect

    Kabadi, V.N.

    1995-06-30

    The work on this project was initiated on September 1, 1991. The project consisted of two different tasks: (1) Development of a model to compute viscosities of coal derived liquids, and (2) Investigate new models for estimation of thermodynamic properties of solid and liquid compounds of the type that exist in coal, or are encountered during coal processing. As for task 1, a model for viscosity computation of coal model compound liquids and coal derived liquids has been developed. The detailed model is presented in this report. Two papers, the first describing the pure liquid model and the second one discussing the application to coal derived liquids, are expected to be published in Energy & Fuels shortly. Marginal progress is reported on task 2. Literature review for this work included compilation of a number of data sets, critical investigation of data measurement techniques available in the literature, investigation of models for liquid and solid phase thermodynamic computations. During the preliminary stages it was discovered that for development of a liquid or solid state equation of state, accurate predictive models for a number of saturation properties, such as, liquid and solid vapor pressures, saturated liquid and solid volumes, heat capacities of liquids and solids at saturation, etc. Most the remaining time on this task was spent in developing predictive correlations for vapor pressures and saturated liquid volumes of organic liquids in general and coal model liquids in particular. All these developments are discussed in this report. Some recommendations for future direction of research in this area are also listed.

  15. Detailed monitoring of two biogas plants and mechanical solid-liquid separation of fermentation residues.

    PubMed

    Bauer, Alexander; Mayr, Herwig; Hopfner-Sixt, Katharina; Amon, Thomas

    2009-06-01

    The Austrian "green electricity act" (Okostromgesetz) has led to an increase in biogas power plant size and consequently to an increased use of biomass. A biogas power plant with a generating capacity of 500 kW(el) consumes up to 38,000 kg of biomass per day. 260 ha of cropland is required to produce this mass. The high water content of biomass necessitates a high transport volume for energy crops and fermentation residues. The transport and application of fermentation residues to farmland is the last step in this logistic chain. The use of fermentation residues as fertilizer closes the nutrient cycle and is a central element in the efficient use of biomass for power production. Treatment of fermentation residues by separation into liquid and solid phases may be a solution to the transport problem. This paper presents detailed results from the monitoring of two biogas plants and from the analysis of the separation of fermentation residues. Furthermore, two different separator technologies for the separation of fermentation residues of biogas plants were analyzed. The examined biogas plants correspond to the current technological state of the art and have designs developed specifically for the utilization of energy crops. The hydraulic retention time ranged between 45.0 and 83.7 days. The specific methane yields were 0.40-0.43 m(3)N CH(4) per kg VS. The volume loads ranged between 3.69 and 4.00 kg VS/m(3). The degree of degradation was between 77.3% and 82.14%. The screw extractor separator was better suited for biogas slurry separation than the rotary screen separator. The screw extractor separator exhibited a high throughput and good separation efficiency. The efficiency of slurry separation depended on the dry matter content of the fermentation residue. The higher the dry matter content, the higher the proportion of solid phase after separation. In this project, we found that the fermentation residues could be divided into 79.2% fluid phase with a dry matter

  16. Thermodynamic study of binary system Propafenone Hydrocloride with Metoprolol Tartrate: solid-liquid equilibrium and compatibility with α-lactose monohydrate and corn starch.

    PubMed

    Marinescu, Daniela-Crina; Pincu, Elena; Meltzer, Viorica

    2013-05-20

    Solid-liquid equilibrium (SLE) for binary mixture of Propafenone Hydrocloride (PP) with Metoprolol Tartrate (MT) was investigated using differential scanning calorimetry (DSC) and corresponding activity coefficients were calculated. Simple eutectic behavior for this system was observed. The excess thermodynamic functions: G(E) and S(E) for the pre-, post-, and eutectic composition have been obtained using the computed activity coefficients data of the eutectic phase with their excess chemical potentials μi(E) (i=1, 2). The experimental solid-liquid phase temperatures were compared with predictions obtained from available eutectic equilibrium models. The results indicate non-ideality in this mixture. Also, the compatibility of each component and their eutectic mixture with usual excipients was investigated, and the DSC experiments indicate possible weak interactions with α-lactose monohydrate and compatibility with corn starch. The results obtained were confirmed by FT-IR measurements. PMID:23545398

  17. Thermodynamic and rheological properties of solid-liquid systems in coal processing. Quarterly technical report, March 1, 1992--May 31, 1992

    SciTech Connect

    Kabadi, V.N.; Ilias, S.

    1992-12-31

    In this report we present two data sets that have been compiled to assist in the model developments for solid-liquid equilibria and viscosities of coal derived systems. The first one is on vapor pressures of solid aromatics and the second one consists of viscosities of pure model compounds and some mixtures. These databanks are ready for usage in model development and are summarized in Tables 1 and 2. Literature is being searched to compile similar data for high pressure liquid compressibilities, liquid and solid heat capacities and solid-liquid equilibria for model compound systems. Literature search is also containing to investigate available viscosity models. Once this is completed a few models will be selected for evaluation and consideration as candidates for extension to coal liquids.

  18. The effects of liquid composition, temperature, and pressure on the equilibrium dihedral angles of binary solid-liquid systems inferred from a lattice-like model

    NASA Astrophysics Data System (ADS)

    Takei, Yasuko; Shimizu, Ichiko

    2003-10-01

    Dihedral angles of binary eutectic systems, such as silicate+melt systems, silicate+H 2O systems, binary alloys, and binary organic systems, tend to decrease with increasing concentration of the solid component in the liquid phase. This empirical law is useful to estimate dihedral angles in the Earth's interior from phase diagrams of solid-liquid systems. In this paper, we investigate the mechanism underlying this empirical law. By employing a lattice-like model in which the liquid phase is treated as a regular solution, we clarify the liquid composition, temperature, and pressure effects on the solid-liquid interfacial tension. It is shown that the non-ideality in chemical bonding causes a strong compositional dependence of the solid-liquid interfacial tension; due to the non-ideality in chemical bonding, the solid surface preferentially adsorbs the solid component, which results in the decrease of the interfacial tension with increasing concentration of this component in the bulk liquid phase. With this effect, the significant decrease of the dihedral angle with T observed in the SiO 2-H 2O system near the monotectic temperature, and the decrease with P observed in the forsterite-H 2O system, can be explained semi-quantitatively.

  19. Thermoelectric Magnetohydrodynamic Flows and Their Induced Change of Solid-Liquid Interface Shape in Static Magnetic Field-Assisted Directional Solidification

    NASA Astrophysics Data System (ADS)

    Wang, Jiang; Fautrelle, Yves; Nguyen-Thi, Henri; Reinhart, Guillaume; Liao, Hanlin; Li, Xi; Zhong, Yunbo; Ren, Zhongming

    2016-03-01

    Applying static magnetic field can produce flows (thermoelectric magnetohydrodynamic flows, TEMHDF) in the melt by interacting with the thermoelectric currents (TEC) during solidification of metals. A physical model was proposed to interpret how these TEC appear at the solid-liquid interface and verified by a corresponding simulation. The influences of TEMHDF on solidification were investigated through both ex-situ experiments and n situ observations by means of synchrotron X-ray radiography. The 3D numerical simulations of TEMHDF were performed for these two cases, respectively, and suggested that both the change of interface shape with different transverse static magnetic fields demonstrated by the ex-situ experiments and the real time observed interface shape varying under a 0.08 T transverse static magnetic field could attribute to the TEMHDF advanced solid-liquid interface in the static magnetic field-assisted directional solidification. The TEMHDF produced by an axial static magnetic field were also computed along with the interface change predicted based on which is good in line with the published experimental results. This study of TEMHDF and their impacts on the solid-liquid interface shape provides a method to tailor the structure during directional solidification using static magnetic field.

  20. Using “Tender” x-ray ambient pressure x-Ray photoelectron spectroscopy as a direct probe of solid-liquid interface

    SciTech Connect

    Axnanda, Stephanus; Crumlin, Ethan J.; Mao, Baohua; Rani, Sana; Chang, Rui; Karlsson, Patrik G.; Edwards, Mårten O. M.; Lundqvist, Måns; Moberg, Robert; Ross, Phil; Hussain, Zahid; Liu, Zhi

    2015-05-07

    We report a new method to probe the solid-liquid interface through the use of a thin liquid layer on a solid surface. An ambient pressure XPS (AP-XPS) endstation that is capable of detecting high kinetic energy photoelectrons (7 keV) at a pressure up to 110 Torr has been constructed and commissioned. Additionally, we have deployed a “dip & pull” method to create a stable nanometers-thick aqueous electrolyte on platinum working electrode surface. Combining the newly constructed AP-XPS system, “dip & pull” approach, with a “tender” X-ray synchrotron source (2 keV–7 keV), we are able to access the interface between liquid and solid dense phases with photoelectrons and directly probe important phenomena occurring at the narrow solid-liquid interface region in an electrochemical system. Using this approach, we have performed electrochemical oxidation of the Pt electrode at an oxygen evolution reaction (OER) potential. Under this potential, we observe the formation of both Pt²⁺ and Pt⁴⁺ interfacial species on the Pt working electrode in situ. We believe this thin-film approach and the use of “tender” AP-XPS highlighted in this study is an innovative new approach to probe this key solid-liquid interface region of electrochemistry.

  1. Using “Tender” x-ray ambient pressure x-Ray photoelectron spectroscopy as a direct probe of solid-liquid interface

    DOE PAGESBeta

    Axnanda, Stephanus; Crumlin, Ethan J.; Mao, Baohua; Rani, Sana; Chang, Rui; Karlsson, Patrik G.; Edwards, Mårten O. M.; Lundqvist, Måns; Moberg, Robert; Ross, Phil; et al

    2015-05-07

    We report a new method to probe the solid-liquid interface through the use of a thin liquid layer on a solid surface. An ambient pressure XPS (AP-XPS) endstation that is capable of detecting high kinetic energy photoelectrons (7 keV) at a pressure up to 110 Torr has been constructed and commissioned. Additionally, we have deployed a “dip & pull” method to create a stable nanometers-thick aqueous electrolyte on platinum working electrode surface. Combining the newly constructed AP-XPS system, “dip & pull” approach, with a “tender” X-ray synchrotron source (2 keV–7 keV), we are able to access the interface between liquidmore » and solid dense phases with photoelectrons and directly probe important phenomena occurring at the narrow solid-liquid interface region in an electrochemical system. Using this approach, we have performed electrochemical oxidation of the Pt electrode at an oxygen evolution reaction (OER) potential. Under this potential, we observe the formation of both Pt²⁺ and Pt⁴⁺ interfacial species on the Pt working electrode in situ. We believe this thin-film approach and the use of “tender” AP-XPS highlighted in this study is an innovative new approach to probe this key solid-liquid interface region of electrochemistry.« less

  2. Using “Tender” X-ray Ambient Pressure X-Ray Photoelectron Spectroscopy as A Direct Probe of Solid-Liquid Interface

    PubMed Central

    Axnanda, Stephanus; Crumlin, Ethan J.; Mao, Baohua; Rani, Sana; Chang, Rui; Karlsson, Patrik G.; Edwards, Mårten O. M.; Lundqvist, Måns; Moberg, Robert; Ross, Phil; Hussain, Zahid; Liu, Zhi

    2015-01-01

    We report a new method to probe the solid-liquid interface through the use of a thin liquid layer on a solid surface. An ambient pressure XPS (AP-XPS) endstation that is capable of detecting high kinetic energy photoelectrons (7 keV) at a pressure up to 110 Torr has been constructed and commissioned. Additionally, we have deployed a “dip & pull” method to create a stable nanometers-thick aqueous electrolyte on platinum working electrode surface. Combining the newly constructed AP-XPS system, “dip & pull” approach, with a “tender” X-ray synchrotron source (2 keV–7 keV), we are able to access the interface between liquid and solid dense phases with photoelectrons and directly probe important phenomena occurring at the narrow solid-liquid interface region in an electrochemical system. Using this approach, we have performed electrochemical oxidation of the Pt electrode at an oxygen evolution reaction (OER) potential. Under this potential, we observe the formation of both Pt2+ and Pt4+ interfacial species on the Pt working electrode in situ. We believe this thin-film approach and the use of “tender” AP-XPS highlighted in this study is an innovative new approach to probe this key solid-liquid interface region of electrochemistry. PMID:25950241

  3. Using “Tender” X-ray Ambient Pressure X-Ray Photoelectron Spectroscopy as A Direct Probe of Solid-Liquid Interface

    NASA Astrophysics Data System (ADS)

    Axnanda, Stephanus; Crumlin, Ethan J.; Mao, Baohua; Rani, Sana; Chang, Rui; Karlsson, Patrik G.; Edwards, Mårten O. M.; Lundqvist, Måns; Moberg, Robert; Ross, Phil; Hussain, Zahid; Liu, Zhi

    2015-05-01

    We report a new method to probe the solid-liquid interface through the use of a thin liquid layer on a solid surface. An ambient pressure XPS (AP-XPS) endstation that is capable of detecting high kinetic energy photoelectrons (7 keV) at a pressure up to 110 Torr has been constructed and commissioned. Additionally, we have deployed a “dip & pull” method to create a stable nanometers-thick aqueous electrolyte on platinum working electrode surface. Combining the newly constructed AP-XPS system, “dip & pull” approach, with a “tender” X-ray synchrotron source (2 keV-7 keV), we are able to access the interface between liquid and solid dense phases with photoelectrons and directly probe important phenomena occurring at the narrow solid-liquid interface region in an electrochemical system. Using this approach, we have performed electrochemical oxidation of the Pt electrode at an oxygen evolution reaction (OER) potential. Under this potential, we observe the formation of both Pt2+ and Pt4+ interfacial species on the Pt working electrode in situ. We believe this thin-film approach and the use of “tender” AP-XPS highlighted in this study is an innovative new approach to probe this key solid-liquid interface region of electrochemistry.

  4. Numerical Calculation of the Drag Force Acting on a Solid Particle Pushed by a Solid/Liquid Interface

    NASA Technical Reports Server (NTRS)

    Catalina, Adrian V.; Stefanescu, Doru M.; Sen, Subhayu

    2000-01-01

    The distribution of insoluble particles in a metal casting depends primarily on the interaction of the particles with the solid/liquid interface (SLI) during the solidification process. The balance of the forces acting on the particle essentially determines whether a particle will be engulfed or pushed by the SLI. An important component of this force balance is the drag force generated by the particle motion in front of the SLI. Previously developed mathematical models for particle/SLI interaction made use of steady-state solutions of this force provided by the lubrication theory. However, our numerical model based on the SLI tracking approach shows that the steady-state approach is inappropriate to model the interaction process and that at steady-state the theoretical solution underestimates the drag force. It was found that regression analysis of steady-state numerical solutions for cylindrical particles moving normal to a flat SLI gives a relationship of the form: Abstract The distribution of insoluble particles in a metal casting depends primarily on the interaction of the particles with the solid/liquid interface (SLI) during the solidification process. The balance of the forces acting on the particle essentially determines whether a particle will be engulfed or pushed by the SLI. An important component of this force balance is the drag force generated by the particle motion in front of the SLI. Previously developed mathematical models for particle/SLI interaction made use of steady-state solutions of this force provided by the lubrication theory. However, our numerical model based on the SLI tracking approach shows that the steady-state approach is inappropriate to model the interaction process and that at steady-state the theoretical solution underestimates the drag force. It was found that regression analysis of steady-state numerical solutions for cylindrical particles moving normal to a flat SLI gives a relationship of the form: F(sub D, sup num) =sqoare

  5. Spectrofluorimetric determination of melatonin in kernels of four different Pistacia varieties after ultrasound-assisted solid-liquid extraction

    NASA Astrophysics Data System (ADS)

    Oladi, Elham; Mohamadi, Maryam; Shamspur, Tayebeh; Mostafavi, Ali

    2014-11-01

    Melatonin is normally consumed to regulate the body's biological cycle. However it also has therapeutic properties, such as anti-tumor, anti-aging and protects the immune system. There are some reports on the presence of melatonin in edible kernels such as walnuts, but the extraction of melatonin from pistachio kernels is reported here for the first time. For this, the methanolic extract of pistachio kernels was exposed to gas chromatography/mass spectrometry analysis which confirmed the presence of melatonin. A fluorescence-based method was applied for the determination of melatonin in different extracts. When excited at λ = 275 nm, the fluorescence emission intensity of melatonin was measured at λ = 366 nm. Ultrasound-assisted solid-liquid extraction was used for the extraction of melatonin from pistachio kernels prior to fluorimetric determination. To achieve the highest extraction recovery, the main parameters affecting the extraction efficiency such as extracting solvent type and volume, temperature, sonication time and pH were evaluated. Under the optimized conditions, a linear dependence of fluorescence intensity on melatonin concentration was observed in the range of 0.0040-0.160 μg mL-1, with a detection limit of 0.0036 μg mL-1. This method was applied successfully for measuring and comparing the melatonin content in the kernels of four different varieties of Pistacia including Ahmad Aghaei, Akbari, Kalle Qouchi and Fandoghi. In addition, the results obtained were compared with those obtained using GC/MS. A good agreement was observed indicating the reliability of the proposed method.

  6. Order-parameter-aided temperature-accelerated sampling for the exploration of crystal polymorphism and solid-liquid phase transitions

    PubMed Central

    Yu, Tang-Qing; Chen, Pei-Yang; Chen, Ming; Samanta, Amit; Vanden-Eijnden, Eric; Tuckerman, Mark

    2014-01-01

    The problem of predicting polymorphism in atomic and molecular crystals constitutes a significant challenge both experimentally and theoretically. From the theoretical viewpoint, polymorphism prediction falls into the general class of problems characterized by an underlying rough energy landscape, and consequently, free energy based enhanced sampling approaches can be brought to bear on the problem. In this paper, we build on a scheme previously introduced by two of the authors in which the lengths and angles of the supercell are targeted for enhanced sampling via temperature accelerated adiabatic free energy dynamics [T. Q. Yu and M. E. Tuckerman, Phys. Rev. Lett. 107, 015701 (2011)]. Here, that framework is expanded to include general order parameters that distinguish different crystalline arrangements as target collective variables for enhanced sampling. The resulting free energy surface, being of quite high dimension, is nontrivial to reconstruct, and we discuss one particular strategy for performing the free energy analysis. The method is applied to the study of polymorphism in xenon crystals at high pressure and temperature using the Steinhardt order parameters without and with the supercell included in the set of collective variables. The expected fcc and bcc structures are obtained, and when the supercell parameters are included as collective variables, we also find several new structures, including fcc states with hcp stacking faults. We also apply the new method to the solid-liquid phase transition in copper at 1300 K using the same Steinhardt order parameters. Our method is able to melt and refreeze the system repeatedly, and the free energy profile can be obtained with high efficiency. PMID:24907992

  7. Order-parameter-aided temperature-accelerated sampling for the exploration of crystal polymorphism and solid-liquid phase transitions

    SciTech Connect

    Yu, Tang-Qing Vanden-Eijnden, Eric; Chen, Pei-Yang; Chen, Ming; Samanta, Amit; Tuckerman, Mark

    2014-06-07

    The problem of predicting polymorphism in atomic and molecular crystals constitutes a significant challenge both experimentally and theoretically. From the theoretical viewpoint, polymorphism prediction falls into the general class of problems characterized by an underlying rough energy landscape, and consequently, free energy based enhanced sampling approaches can be brought to bear on the problem. In this paper, we build on a scheme previously introduced by two of the authors in which the lengths and angles of the supercell are targeted for enhanced sampling via temperature accelerated adiabatic free energy dynamics [T. Q. Yu and M. E. Tuckerman, Phys. Rev. Lett. 107, 015701 (2011)]. Here, that framework is expanded to include general order parameters that distinguish different crystalline arrangements as target collective variables for enhanced sampling. The resulting free energy surface, being of quite high dimension, is nontrivial to reconstruct, and we discuss one particular strategy for performing the free energy analysis. The method is applied to the study of polymorphism in xenon crystals at high pressure and temperature using the Steinhardt order parameters without and with the supercell included in the set of collective variables. The expected fcc and bcc structures are obtained, and when the supercell parameters are included as collective variables, we also find several new structures, including fcc states with hcp stacking faults. We also apply the new method to the solid-liquid phase transition in copper at 1300 K using the same Steinhardt order parameters. Our method is able to melt and refreeze the system repeatedly, and the free energy profile can be obtained with high efficiency.

  8. Modeling migrations of slab-derived fluid in deep crust based on the considerations of solid phase deformation and wettability of solid-liquid system

    NASA Astrophysics Data System (ADS)

    Ohta, J.; Tokunaga, T.

    2012-12-01

    In deep crust, it is considered that the solid phase tends to keep its polycrystalline structure while it flows as highly-viscous fluid, and that the fluid phase flows through polycrystalline solid as porous flow. Here, the solid-framework is considered to change its bulk volume due to the changes of fluid volumetric fraction. In addition, wettability of solid-liquid system, which is expressed as solid-liquid dihedral angle, is also considered to affect internal pore structure. Thus, the solid-framework deformation and wettability of solid-liquid system are considered to influence fluid migration. In this research, we firstly constructed the permeability model to formulate a relationship among solid-liquid dihedral angle, fluid fraction, and permeability based on the energetic and textural considerations of grain boundary interface. The permeability and the fluid fraction under minimum interfacial energy condition were expressed as functions of solid-liquid dihedral angle from this model. Then, we found that permeability can be written as functions of the fluid fraction and the permeability under minimum interfacial energy condition. Secondly, we formulated the deformation of solid-framework and fluid flow through the deforming framework. The governing equations included solid bulk viscosity and solid shear viscosity as necessary parameters to describe the behavior. Based on the derived governing equations, the one-dimensional numerical simulations were conducted with different solid viscosities. From the results where solid bulk/shear viscosity was set to be 1020 Pa×s, intervals with relatively high fluid fraction were formed and the intervals showed attenuated fluctuation of their fluid volume fraction. On the other hand, the results where solid bulk/shear viscosity was set to be 1019 Pa×s did not show such fluctuation. The complex interaction among fluid fraction, permeability, and solid viscosity could contribute to the observed phenomena, and further

  9. A Raman Spectroscopy and High-Speed Video Experimental Study: The Effect of Pressure on the Solid-Liquid Transformation Kinetics of N-octane

    NASA Astrophysics Data System (ADS)

    Liu, C.; Wang, D.

    2015-12-01

    Phase transitions of minerals and rocks in the interior of the Earth, especially at elevated pressures and temperatures, can make the crystal structures and state parameters obviously changed, so it is very important for the physical and chemical properties of these materials. It is known that the transformation between solid and liquid is relatively common in nature, such as the melting of ice and the crystallization of mineral or water. The kinetics relevant to these transformations might provide valuable information on the reaction rate and the reaction mechanism involving nucleation and growth. An in-situ transformation kinetic study of n-octane, which served as an example for this type of phase transition, has been carried out using a hydrothermal diamond anvil cell (HDAC) and high-speed video technique, and that the overall purpose of this study is to develop a comprehensive understanding of the reaction mechanism and the influence of pressure on the different transformation rates. At ambient temperature, the liquid-solid transformation of n-octane first took place with increasing pressure, and then the solid phase gradually transformed into the liquid phase when the sample was heated to a certain temperature. Upon the cooling of the system, the liquid-solid transformation occurred again. According to the established quantitative assessments of the transformation rates, pressure and temperature, it showed that there was a negative pressure dependence of the solid-liquid transformation rate. However, the elevation of pressure can accelerate the liquid-solid transformation rate. Based on the calculated activation energy values, an interfacial reaction and diffusion dominated the solid-liquid transformation, but the liquid-solid transformation was mainly controlled by diffusion. This experimental technique is a powerful and effective tool for the transformation kinetics study of n-octane, and the obtained results are of great significance to the kinetics study

  10. Soins Aux Brules Apres Un Accident Nucleaire

    PubMed Central

    Bargues, L.; Donat, N.; Jault, P.; Leclerc, T.

    2010-01-01

    Summary Les lésions radiques sont dues le plus souvent à des radio-isotopes utilisés dans l’industrie. L’explosion d’un réacteur nucléaire, les armes nucléaires ou une attaque terroriste constituent un risque d’afflux massif de victimes brûlées. Les radiations ionisantes occasionnent des brûlures thermiques, des syndromes d’irradiation aiguë avec pancytopénie et des signes cutanés retardés. Après une période de latence, des symptômes cutanés apparaissent et leur profondeur est proportionnelle à la dose reçue. Les protocoles habituels de réanimation des brûlés s’appliquent ici. Les soins aux irradiés nécessitent aussi une mesure de l’irradiation et une décontamination par des personnels entraînés. En cas de catastrophe nucléaire, la priorité est d’optimiser les structures existantes et de préserver les moyens pour les patients ayant la plus forte probabilité de survie. Après un accident nucléaire isolé, les difficultés dans les centres de brûlés sont l’évaluation de la profondeur et les techniques chirurgicales de couverture cutanée. La préparation des moyens médicaux et des centres de brûlés est nécessaire pour faire face à la prise en charge de ces brûlures différentes et complexes. PMID:21991218

  11. Investigating the influence of production conditions on the energy distribution between the solid, liquid and gaseous products of slow pyrolysis

    NASA Astrophysics Data System (ADS)

    Crombie, Kyle; Masek, Ondrej

    2013-04-01

    calorific value due to the increased emission of volatiles. The higher heating value for the syngas was also shown to increase with temperature due to greater release of combustible gas species at higher temperatures. The impact of residence time and gas flow rate were not as clear as for temperature but still demonstrated decreasing biochar yields as the respective parameters were increased. However the greatest impact occurred at 350oC and diminished when temperature was increased to 650oC. An understanding of the influence that production conditions have on the long term stability of biochar as well as the energy content of the solid, liquid and gas fractions obtained from pyrolysis is critical towards the development of specifically engineered biochar to deliver a specific function be it for agricultural use, carbon storage, energy generation or combinations of the three.

  12. Hydrolysis-acidogenesis of food waste in solid-liquid-separating continuous stirred tank reactor (SLS-CSTR) for volatile organic acid production.

    PubMed

    Karthikeyan, Obulisamy Parthiba; Selvam, Ammaiyappan; Wong, Jonathan W C

    2016-01-01

    The use of conventional continuous stirred tank reactor (CSTR) can affect the methane (CH4) recovery in a two-stage anaerobic digestion of food waste (FW) due to carbon short circuiting in the hydrolysis-acidogenesis (Hy-Aci) stage. In this research, we have designed and tested a solid-liquid-separating CSTR (SLS-CSTR) for effective Hy-Aci of FW. The working conditions were pH 6 and 9 (SLS-CSTR-1 and -2, respectively); temperature-37°C; agitation-300rpm; and organic loading rate (OLR)-2gVSL(-1)day(-1). The volatile fatty acids (VFA), enzyme activities and bacterial population (by qPCR) were determined as test parameters. Results showed that the Hy-Aci of FW at pH 9 produced ∼35% excess VFA as compared to that at pH 6, with acetic and butyric acids as major precursors, which correlated with the high enzyme activities and low lactic acid bacteria. The design provided efficient solid-liquid separation there by improved the organic acid yields from FW. PMID:26512860

  13. Determination of the Solid/Liquid Interface Shape and Resultant Radial Homogeneity in Directionally Solidified Hg(0.89)Mn(0.11)Te

    NASA Technical Reports Server (NTRS)

    Price, M. W.; Scripa, R. N.; Lehoczky, S. L.; Szofran, F. R.; Hanson, B.

    1999-01-01

    Directional solidification and interrupted directional solidification experiments were used to determine tile shape of the solid/liquid interface and the resultant radial homogeneity in Hg(0.89)Mg(0.11)Te. For directionally solidified samples solidified at a rate of 0.09 microns/sec in a thermal gradient of 83 C/cm, a maximum of 0.006 molar percent MnTe radial variation across the Hg0.89)Mn(0.11)Te boules at specific locations was determined using an FTIR technique. This FTIR evaluation of the radial homogeneity also indicated an asymmetrical, convex interface shape during solidification. The asymmetrical, convex shape of the growth interface was confirmed by interrupted directional solidification experiments. These were performed under the same growth conditions as the normally completed directional solidification experiments except that the samples were quenched before the final growth transient was reached. In these experiments, etching and scanning X-ray fluorescence were used to reveal the shape of the solid/liquid interface. Microprobe analysis of composition gradients across the interface was used to confirm the authors' previous work in evaluating the segregation coefficient of Hg(0.89)Mn(0.11)Te alloy. Microprobe analysis of the interface region of the interrupted growth sample revealed a dendritic structure containing secondary and tertiary dendritic arms.

  14. Novel, low-cost solid-liquid-solid process for the synthesis of α-Si3N4 nanowires at lower temperatures and their luminescence properties.

    PubMed

    Liu, Haitao; Huang, Zhaohui; Huang, Juntong; Fang, Minghao; Liu, Yan-gai; Wu, Xiaowen; Hu, Xiaozhi; Zhang, Shaowei

    2015-01-01

    Ultra-long, single crystal, α-Si3N4 nanowires sheathed with amorphous silicon oxide were synthesised by an improved, simplified solid-liquid-solid (SLS) method at 1150 °C without using flowing gases (N2, CH4, Ar, NH3, etc.). Phases, chemical composition, and structural characterisation using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM/HRTEM), Fourier-transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) showed that the nanowires had Si3N4@SiOx core-shell structures. The growth of the nanowires was governed by the solid-liquid-solid (SLS) mechanism. The room temperature photoluminescence (PL) and cathodoluminescence (CL) spectra showed that the optical properties of the α-Si3N4 nanowires can be changed along with the excitation wavelength or the excitation light source. This work can be useful, not only for simplifying the design and synthesis of Si-related nanostructures, but also for developing new generation nanodevices with changeable photoelectronic properties. PMID:26607395

  15. A high pressure x-ray photoelectron spectroscopy experimental method for characterization of solid-liquid interfaces demonstrated with a Li-ion battery system

    NASA Astrophysics Data System (ADS)

    Maibach, Julia; Xu, Chao; Eriksson, Susanna K.; Åhlund, John; Gustafsson, Torbjörn; Siegbahn, Hans; Rensmo, Hâkan; Edström, Kristina; Hahlin, Maria

    2015-04-01

    We report a methodology for a direct investigation of the solid/liquid interface using high pressure x-ray photoelectron spectroscopy (HPXPS). The technique was demonstrated with an electrochemical system represented by a Li-ion battery using a silicon electrode and a liquid electrolyte of LiClO4 in propylene carbonate (PC) cycled versus metallic lithium. For the first time the presence of a liquid electrolyte was realized using a transfer procedure where the sample was introduced into a 2 mbar N2 environment in the analysis chamber without an intermediate ultrahigh vacuum (UHV) step in the load lock. The procedure was characterized in detail concerning lateral drop gradients as well as stability of measurement conditions over time. The X-ray photoelectron spectroscopy (XPS) measurements demonstrate that the solid substrate and the liquid electrolyte can be observed simultaneously. The results show that the solid electrolyte interphase (SEI) composition for the wet electrode is stable within the probing time and generally agrees well with traditional UHV studies. Since the methodology can easily be adjusted to various high pressure photoelectron spectroscopy systems, extending the approach towards operando solid/liquid interface studies using liquid electrolytes seems now feasible.

  16. A high pressure x-ray photoelectron spectroscopy experimental method for characterization of solid-liquid interfaces demonstrated with a Li-ion battery system

    SciTech Connect

    Maibach, Julia; Xu, Chao; Gustafsson, Torbjörn; Edström, Kristina; Eriksson, Susanna K.; Åhlund, John; Siegbahn, Hans; Rensmo, Håkan; Hahlin, Maria

    2015-04-15

    We report a methodology for a direct investigation of the solid/liquid interface using high pressure x-ray photoelectron spectroscopy (HPXPS). The technique was demonstrated with an electrochemical system represented by a Li-ion battery using a silicon electrode and a liquid electrolyte of LiClO{sub 4} in propylene carbonate (PC) cycled versus metallic lithium. For the first time the presence of a liquid electrolyte was realized using a transfer procedure where the sample was introduced into a 2 mbar N{sub 2} environment in the analysis chamber without an intermediate ultrahigh vacuum (UHV) step in the load lock. The procedure was characterized in detail concerning lateral drop gradients as well as stability of measurement conditions over time. The X-ray photoelectron spectroscopy (XPS) measurements demonstrate that the solid substrate and the liquid electrolyte can be observed simultaneously. The results show that the solid electrolyte interphase (SEI) composition for the wet electrode is stable within the probing time and generally agrees well with traditional UHV studies. Since the methodology can easily be adjusted to various high pressure photoelectron spectroscopy systems, extending the approach towards operando solid/liquid interface studies using liquid electrolytes seems now feasible.

  17. Novel, low-cost solid-liquid-solid process for the synthesis of α-Si3N4 nanowires at lower temperatures and their luminescence properties

    NASA Astrophysics Data System (ADS)

    Liu, Haitao; Huang, Zhaohui; Huang, Juntong; Fang, Minghao; Liu, Yan-Gai; Wu, Xiaowen; Hu, Xiaozhi; Zhang, Shaowei

    2015-11-01

    Ultra-long, single crystal, α-Si3N4 nanowires sheathed with amorphous silicon oxide were synthesised by an improved, simplified solid-liquid-solid (SLS) method at 1150 °C without using flowing gases (N2, CH4, Ar, NH3, etc.). Phases, chemical composition, and structural characterisation using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM/HRTEM), Fourier-transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) showed that the nanowires had Si3N4@SiOx core-shell structures. The growth of the nanowires was governed by the solid-liquid-solid (SLS) mechanism. The room temperature photoluminescence (PL) and cathodoluminescence (CL) spectra showed that the optical properties of the α-Si3N4 nanowires can be changed along with the excitation wavelength or the excitation light source. This work can be useful, not only for simplifying the design and synthesis of Si-related nanostructures, but also for developing new generation nanodevices with changeable photoelectronic properties.

  18. Novel, low-cost solid-liquid-solid process for the synthesis of α-Si3N4 nanowires at lower temperatures and their luminescence properties

    PubMed Central

    Liu, Haitao; Huang, Zhaohui; Huang, Juntong; Fang, Minghao; Liu, Yan-gai; Wu, Xiaowen; Hu, Xiaozhi; Zhang, Shaowei

    2015-01-01

    Ultra-long, single crystal, α-Si3N4 nanowires sheathed with amorphous silicon oxide were synthesised by an improved, simplified solid-liquid-solid (SLS) method at 1150 °C without using flowing gases (N2, CH4, Ar, NH3, etc.). Phases, chemical composition, and structural characterisation using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM/HRTEM), Fourier-transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) showed that the nanowires had Si3N4@SiOx core-shell structures. The growth of the nanowires was governed by the solid-liquid-solid (SLS) mechanism. The room temperature photoluminescence (PL) and cathodoluminescence (CL) spectra showed that the optical properties of the α-Si3N4 nanowires can be changed along with the excitation wavelength or the excitation light source. This work can be useful, not only for simplifying the design and synthesis of Si-related nanostructures, but also for developing new generation nanodevices with changeable photoelectronic properties. PMID:26607395

  19. Impact of ultrasound on solid-liquid extraction of phenolic compounds from maritime pine sawdust waste. Kinetics, optimization and large scale experiments.

    PubMed

    Meullemiestre, A; Petitcolas, E; Maache-Rezzoug, Z; Chemat, F; Rezzoug, S A

    2016-01-01

    Maritime pine sawdust, a by-product from industry of wood transformation, has been investigated as a potential source of polyphenols which were extracted by ultrasound-assisted maceration (UAM). UAM was optimized for enhancing extraction efficiency of polyphenols and reducing time-consuming. In a first time, a preliminary study was carried out to optimize the solid/liquid ratio (6g of dry material per mL) and the particle size (0.26 cm(2)) by conventional maceration (CVM). Under these conditions, the optimum conditions for polyphenols extraction by UAM, obtained by response surface methodology, were 0.67 W/cm(2) for the ultrasonic intensity (UI), 40°C for the processing temperature (T) and 43 min for the sonication time (t). UAM was compared with CVM, the results showed that the quantity of polyphenols was improved by 40% (342.4 and 233.5mg of catechin equivalent per 100g of dry basis, respectively for UAM and CVM). A multistage cross-current extraction procedure allowed evaluating the real impact of UAM on the solid-liquid extraction enhancement. The potential industrialization of this procedure was implemented through a transition from a lab sonicated reactor (3 L) to a large scale one with 30 L volume. PMID:26384903

  20. Solid-liquid hybrid assembly for ultrasonic elasticity measurements under hydrostatic conditions of up to 8 GPa in a Kawai-type multianvil apparatus

    NASA Astrophysics Data System (ADS)

    Song, M.; Yoneda, A.; Ito, E.

    2005-03-01

    A solid-liquid hybrid assembly has been designed for ultrasonic elasticity measurements of materials under hydrostatic conditions in a Kawai-type multianvil apparatus. In the assembly, a tungsten-carbide cubic anvil served as the buffer rod for the acoustic signals. The transducer and sample were mounted on two diagonally opposite truncated corners of the buffer-rod anvil. The sample was immersed in a liquid cell filled with a liquid pressure medium, a methanol-ethanol mixture (4:1 in volume), which produced hydrostatic conditions for the sample. The pressure was monitored with a bismuth pressure calibrant inside the liquid cell. Preliminary experiments using single-crystal MgO, polycrystal alumina, and silicate glass samples were successfully conducted up to 8GPa. This assembly is especially useful for precise elasticity measurements of single-crystal samples under hydrostatic compression.

  1. Comparison between 2 methods of solid-liquid extraction for the production of Cinchona calisaya elixir: an experimental kinetics and numerical modeling approach.

    PubMed

    Naviglio, Daniele; Formato, Andrea; Gallo, Monica

    2014-09-01

    The purpose of this study is to compare the extraction process for the production of China elixir starting from the same vegetable mixture, as performed by conventional maceration or a cyclically pressurized extraction process (rapid solid-liquid dynamic extraction) using the Naviglio Extractor. Dry residue was used as a marker for the kinetics of the extraction process because it was proportional to the amount of active principles extracted and, therefore, to their total concentration in the solution. UV spectra of the hydroalcoholic extracts allowed for the identification of the predominant chemical species in the extracts, while the organoleptic tests carried out on the final product provided an indication of the acceptance of the beverage and highlighted features that were not detectable by instrumental analytical techniques. In addition, a numerical simulation of the process has been performed, obtaining useful information about the timing of the process (time history) as well as its mathematical description. PMID:25154593

  2. Molecular beam epitaxy growth of niobium oxides by solid/liquid state oxygen source and lithium assisted metal-halide chemistry

    NASA Astrophysics Data System (ADS)

    Tellekamp, M. Brooks; Greenlee, Jordan D.; Shank, Joshua C.; Doolittle, W. Alan

    2015-09-01

    In order to consistently grow high quality niobium oxides and lithium niobium oxides, a novel solid/liquid state oxygen source, LiClO4, has been implemented in a molecular beam epitaxy (MBE) system. LiClO4 is shown to decompose into both molecular and atomic oxygen upon heating. This allows oxidation rates similar to that of molecular oxygen but at a reduced overall beam flux, quantified by in situ Auger analysis. LiClO4 operation is decomposition limited to less than 400 °C, and other material limitations are identified. The design of a custom near-ambient NbCl5 effusion cell is presented, which improves both short and long term stability. Films of Nb oxidation state +2, +3, and +5 are grown using these new tools, including the multi-functional sub-oxide LiNbO2.

  3. The movement of particles in liquid metals under gravity forces and the interaction of particles with advancing solid-liquid interface

    NASA Technical Reports Server (NTRS)

    Weinberg, F.

    1984-01-01

    The problems of shrinkage and gas porosity are discussed. Gravity forces enhance the removal of gas bubbles from a metal melt and contribute to the feeding of shrinkage porosity in castings. Experiments are reviewed which determine how large a density difference is required for metal particles to float or sink in a metal melt and to what extent do factors not considered in Stokes Law influence particle movement in a real system. As to the interaction of particles with an advancing solid-liquid interface, the results indicate that the metal particles are not rejected in a metal melt, and that concentrations of particles in a metal following solidification are due to other factors.

  4. THE PROCESS OF MASS TRANSFER ON THE SOLID-LIQUID BOUNDARY LAYER DURING THE RELEASE OF DICLOFENAC SODIUM AND PAPAVERINE HYDROCHLORIDE FROM TABLETS IN A PADDLE APPARATUS.

    PubMed

    Kasperek, Regina; Zimmer, Lukasz; Poleszak, Ewa

    2016-01-01

    The release study of diclofenac sodium (DIC) and papaverine hydrochloride (PAP) from two formulations of the tablets in the paddle apparatus using different rotation speeds to characterize the process of mass transfer on the solid-liquid boundary layer was carried out. The dissolution process of active substances was described by values of mass transfer coefficients, the diffusion boundary layer thickness and dimensionless numbers (Sh and Re). The values of calculated parameters showed that the release of DIC and PAP from tablets comprising potato starch proceeded faster than from tablets containing HPMC and microcrystalline cellulose. They were obtained by direct dependencies between Sh and Re in the range from 75 rpm to 125 rpm for both substances from all tablets. The description of the dissolution process with the dimensionless numbers make it possible to plan the drug with the required release profile under given in vitro conditions. PMID:27008811

  5. Improved reactor performance and operability in the biotransformation of carveol to carvone using a solid-liquid two-phase partitioning bioreactor.

    PubMed

    Morrish, Jenna L E; Daugulis, Andrew J

    2008-12-01

    In an effort to improve reactor performance and process operability, the microbial biotransformation of (-)-trans-carveol to (R)-(-)-carvone by hydrophobic Rhodococcus erythropolis DCL14 was carried out in a two phase partitioning bioreactor (TPPB) with solid polymer beads acting as the partitioning phase. Previous work had demonstrated that the substrate and product become inhibitory to the organism at elevated aqueous concentrations and the use of an immiscible second phase in the bioreactor was intended to provide a reservoir for substrates to be delivered to the aqueous phase based on the metabolic rate of the cells, while also acting as a sink to uptake the product as it is produced. The biotransformation was previously undertaken in a two liquid phase TPPB with 1-dodecene and with silicone oil as the immiscible second phase and, although improvement in the reactor performance was obtained relative to a single phase system, the hydrophobic nature of the organism caused the formation of severe emulsions leading to significant operational challenges. In the present work, eight types of polymer beads were screened for their suitability for use in a solid-liquid TPPB for this biotransformation. The use of selected solid polymer beads as the second phase completely prevented emulsion formation and therefore improved overall operability of the reactor. Three modes of solid-liquid TPPB operation were considered: the use of a single polymer bead type (styrene/butadiene copolymer) in the reactor, the use of a mixture of polymer beads in the reactor (styrene/butadiene copolymer plus Hytrel(R) 8206), and the use of one type of polymer beads in the reactor (styrene/butadiene copolymer), and another bead type (Hytrel(R) 8206) in an external column through which fermentation medium was recirculated. This last configuration achieved the best reactor performance with 7 times more substrate being added throughout the biotransformation relative to a single aqueous phase

  6. Effects of tilt angle of mirror-lamp system on shape of solid-liquid interface of silicon melt during floating zone growth using infrared convergent heating

    NASA Astrophysics Data System (ADS)

    Hossain, Md. Mukter; Watauchi, Satoshi; Nagao, Masanori; Tanaka, Isao

    2016-01-01

    The tilt effects of the mirror-lamp (M-L) system on the shape of the interface of the silicon molten zone formed during growth using the infrared convergent heating floating zone method were studied at various positions of the M-L system. The stability and the interfaces of the molten zone formed in the tilted condition were compared with those in the no tilt condition. The molten zone appeared to be more stabilized in the tilted condition than in the no tilt condition. However, the conventional parameters characterizing the interface shape such as convexities (h/r), gap and zone length (L) were almost independent of the tilt angle (θ) of the M-L system and insufficient to discuss the tilting effects on the molten zone shape. The curvature of the solid-liquid interface was affected by the θ. New characterizing parameters such as the growth interface and triple point angles (δ and TPA, respectively) were effective to quantitatively describe the tilting effects on the interface shape. With increase of the θ, the δ was decreased and the TPA was increased in both the feed and crystal sides. A silicon crystal of 45 mm in diameter was grown successfully in the tilted condition.

  7. Low energy electron diffraction (LEED) and sum frequency generation (SFG) vibrational spectroscopy studies of solid-vacuum, solid-air and solid-liquid interfaces

    SciTech Connect

    Hoffer, Saskia

    2002-08-19

    Electron based surface probing techniques can provide detailed information about surface structure or chemical composition in vacuum environments. The development of new surface techniques has made possible in situ molecular level studies of solid-gas interfaces and more recently, solid-liquid interfaces. The aim of this dissertation is two-fold. First, by using novel sample preparation, Low Energy Electron Diffraction (LEED) and other traditional ultra high vacuum (UHV) techniques are shown to provide new information on the insulator/vacuum interface. The surface structure of the classic insulator NaCl has been determined using these methods. Second, using sum frequency generation (SFG) surface specific vibrational spectroscopy studies were performed on both the biopolymer/air and electrode/electrolyte interfaces. The surface structure and composition of polyetherurethane-silicone copolymers were determined in air using SFG, atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). SFG studies of the electrode (platinum, gold and copper)/electrolyte interface were performed as a function of applied potential in an electrochemical cell.

  8. Pseudo-stir bar hollow fiber solid/liquid phase microextraction combined with anodic stripping voltammetry for determination of lead and cadmium in water samples.

    PubMed

    Es'haghi, Zarrin; Hoseini, Hasan Ali; Mohammadi-Nokhandani, Saeed; Ebrahimi, Javad

    2014-11-01

    A new procedure is presented for the determination of low concentrations of lead and cadmium in water samples. Ligand assisted pseudo-stir bar hollow fiber solid/liquid phase microextraction using sol-gel sorbent reinforced with carbon nanotubes was combined with differential pulse anodic stripping voltammetry for simultaneous determination of cadmium and lead in tap water, and Darongar river water samples. In the present work, differential pulse anodic stripping voltammetry (DPASV) using a hanging mercury drop electrode (HMDE) was used in order to determine the ultra trace level of lead and cadmium ions in real samples. This method is based on accumulation of lead and cadmium ions on the electrode using different ligands; Quinolin-8-ol, 5,7-diiodo quinoline-8-ol, 4,5-diphenyl-1H-imidazole-2(3H)-one and 2-{[2-(2-Hydroxy-ethylamino)-ethylamino]-methyl}-phenol as the complexing agent. The optimized conditions were obtained. The relationship between the peak current versus concentration was linear over the range of 0.05-500 ng mL(-1) for Cd (II) and Pb (II). The limits of detection for lead and cadmium were 0.015 ng mL(-1) and 0.012 ng mL(-1), respectively. Under the optimized conditions, the pre-concentration factors are 2440 and 3710 for Cd (II) and Pb (II) in 5 mL of water sample, respectively. PMID:25685537

  9. Proposal for new best estimates for the soil solid-liquid distribution coefficient and soil-to-plant transfer of nickel.

    PubMed

    Vandenhove, Hildegarde; Van Hees, May; Olyslaegers, Geert; Vidal, Miquel

    2009-04-01

    The objective of this study was to compile data, based on an extensive literature survey, for the soil solid-liquid distribution coefficient (K(d)) and soil-to-plant transfer factor (TF) for nickel. The K(d) best estimates were calculated for soils grouped according to texture and organic matter content (sand, loam, clay and organic) and soil cofactors affecting soil-nickel interaction, such as pH, organic matter, and clay content. Variability in K(d) was better explained by pH than by soil texture. Nickel TF estimates were presented for major crop groups (cereals, leafy vegetables, non-leafy vegetables, root crops, tubers, fruits, herbs, pastures/grasses and fodder), and also for plant compartments within crop groups. Transfer factors were also calculated per soil group, as defined by their texture and organic matter content. Furthermore an evaluation of transfer factor dependency on specific soil characteristics was performed following regression analysis. The derived estimates were compared with parameter estimates currently in use. PMID:19223096

  10. Self-Assembly of Concentric Hexagons and Hierarchical Self-Assembly of Supramolecular Metal-Organic Nanoribbons at the Solid/Liquid Interface.

    PubMed

    Wang, Ming; Wang, Kun; Wang, Chao; Huang, Mingjun; Hao, Xin-Qi; Shen, Ming-Zhan; Shi, Guo-Qing; Zhang, Zhe; Song, Bo; Cisneros, Alejandro; Song, Mao-Ping; Xu, Bingqian; Li, Xiaopeng

    2016-07-27

    In an effort to exert more precise control over structural features of supramolecules, a series of giant concentric hexagons were assembled as discrete structures using tetratopic terpyridine (tpy) ligands. In preparation of tetratopic ligand, pyrylium and pyridinium salts chemistry significantly facilitated synthesis. The key compounds were obtained by condensation reactions of pyrylium salts with corresponding primary amine derivatives in good yields. These discrete metallo-supramolecular concentric hexagons were fully characterized by NMR, ESI-MS, TWIM-MS, and TEM, establishing their hexagon-in-hexagon architectures. The combination of different tetratopic ligands also assembled hybrid concentric hexagons with increasing diversity and complexity. Furthermore, these concentric hexagon supramolecules with precisely controlled shapes and sizes were utilized as building blocks to hierarchically self-assemble supramolecular metal-organic nanoribbons (SMON) at solid-liquid interfaces. Ambient STM imaging showed the formation of long 1D SMON rather than 2D assembly on the basal plane of highly oriented pyrolytic graphite (HOPG) surface after simple dropcasting of the solution of preassembled concentric hexagons onto a freshly cleaved surface of HOPG. This wet chemical method based on self-assembly may offer simple, economical, and scalable routes to deliver complex materials. PMID:27379457

  11. Numerical research on the effects of impeller pump-out vanes on axial force in a solid-liquid screw centrifugal pump

    NASA Astrophysics Data System (ADS)

    Cheng, X. R.; Li, R. N.; Gao, Y.; Guo, W. L.

    2013-12-01

    A commercial CFD code has been used to predict the performance of a screw centrifugal pump with pump-out vanes, especially when changing regularity of impeller axial force based on the solid-liquid two-phase flow. The Unsteady Reynolds Averaged Navier-Stokes (URANS) approach has been applied to solve the unsteady, incompressible, three-dimensional turbulent. The SIMPLEC algorithm, standard wall functions and mix two-phase flow model were applied. The RNG k ε-model was used to account the turbulence effects. By changing the number of impeller pump-out vanes and width, six different screw centrifugal pump numerical simulation projects were given, and each scheme in the different solid volume fraction were calculated respectively. The change rules of axial force, velocity and pressure distribution of flow field were obtained on the different condition and different volume fraction. The results showed that the axial forces values based solid-fluid two-phase greater than based single-phase clear water, but both changing regularity of the axial force were consistent; as same condition, the same solid-phase volume concentration, with the increase of pump-out vanes number or width, the impeller axial force increased as well. Meanwhile the number of the pump-out vanes and the width of pump-out vanes in balancing the impeller axial force, there are the most optimal value.

  12. Hyperbranched polyglycerol/graphene oxide nanocomposite reinforced hollow fiber solid/liquid phase microextraction for measurement of ibuprofen and naproxen in hair and waste water samples.

    PubMed

    Rezaeifar, Zohreh; Es'haghi, Zarrin; Rounaghi, Gholam Hossein; Chamsaz, Mahmoud

    2016-09-01

    A new design of hyperbranched polyglycerol/graphene oxide nanocomposite reinforced hollow fiber solid/liquid phase microextraction (HBP/GO -HF-SLPME) coupled with high performance liquid chromatography used for extraction and determination of ibuprofen and naproxen in hair and waste water samples. The graphene oxide first synthesized from graphite powders by using modified Hummers approach. The surface of graphene oxide was modified using hyperbranched polyglycerol, through direct polycondensation with thionyl chloride. The ready nanocomposite later wetted by a few microliter of an organic solvent (1-octanol), and then applied to extract the target analytes in direct immersion sampling mode.After the extraction process, the analytes were desorbed with methanol, and then detected via high performance liquid chromatography (HPLC). The experimental setup is very simple and highly affordable. The main factors influencing extraction such as; feed pH, extraction time, aqueous feed volume, agitation speed, the amount of functionalized graphene oxide and the desorption conditions have been examined in detail. Under the optimized experimental conditions, linearity was observed in the range of 5-30,000ngmL(-1) for ibuprofen and 2-10,000ngmL(-1) for naproxen with correlation coefficients of 0.9968 and 0.9925, respectively. The limits of detection were 2.95ngmL(-1) for ibuprofen and 1.51ngmL(-1) for naproxen. The relative standard deviations (RSDs) were found to be less than 5% (n=5). PMID:27428449

  13. Environmental assessment of the HYGAS process. Volume III. Interim report on HYGAS environmental characterization: manual of methods for characterization of HYGAS pilot plant solids, liquids, and gases

    SciTech Connect

    Karst, R.H.; Passaniti, J.L.; Metcalf, T.C.; Salazar, E.V.; Pau, J.C.

    1980-11-01

    The US Department of Energy (DOE) has commissioned the HYGAS environmental assessment program to characterize various solid, liquid, and gaseous streams in the HYGAS pilot plant. The purpose of this manual is to describe the various analytical techniques that have been used to analyze pilot plant streams for environmental species. Many of the techniques have been recommended by the US Environmental Protection Agency or otherwise have been published in ASTM Standards, Standard Methods, and assorted vendor equipment manuals. Complete references have been provided in the text. Analytical techniques for the determination of the following are included: ammonia-nitrogen; biochemical oxygen demand; chemical oxygen demand; chlorides; total cyanide; grease and oil; total organic carbon; phenol; total, suspended, and dissolved solids; sulfide; total sulfur; thiocyanate; total oxygen demand; hydrocyanic acid in gas; hydrogen sulfide in gas; gaseous hydrocarbons; organic compounds in HYGAS light oil and aqueous samples; proximate analysis of coal; ultimate analysis of coal; calorific value; screen analysis; bulk density; and trace elements in coal (arsenic, antimony, selenium, tellurium, barium, beryllium chromium, copper, iron, lithium, manganese, nickel, tin, vanadium, zinc, boron, cadmium, lead, thallium, chlorine, cobalt, fluorine, mercury, and molybdenum). (DMC)

  14. Validation and use of an enzymic time-temperature integrator to monitor thermal impacts inside a solid/liquid model food.

    PubMed

    Guiavarc'h, Yann P; Dintwa, Edward; Van Loey, Ann M; Zuber, François T; Hendrickx, Marc E

    2002-01-01

    Heat denaturation kinetics of Bacillus licheniformis alpha-amylase, equilibrated at 81% equilibrium relative humidity at 4 degrees C (BLA81), was studied with help of isothermal and nonisothermal conditions by monitoring the decrease in enthalpy associated with the heat denaturation of the enzyme. Due to its low water content, BLA81 denaturation could be studied in the range of 118-124 degrees C. Two batches of BLA81 were successfully validated under nonisothermal conditions allowing the determinations of process values (reference temperature of 121.1 degrees C) in the range of 1-15 min. In a second step, BLA81 was used as a time-temperature integrator (TTI) to investigate potential differences of process values received by freely moving spherical particles as compared to a centrally fixed particle (single-position impact) inside cans containing water as brine. Results showed that the process value received by freely moving particles can be from 5.6% (4 rpm) to 19.7% (8 rpm) smaller than the process value received by the centrally fixed sphere. This means that evaluating the process value by means of a particle fixed at the critical point in a package can lead to potentially overestimations of the actual process value with possible hazardous quality/safety implications. These results highlight the potentials of the TTI technology to monitor the safety of heat-processed agitated solid/liquid foodstuffs. PMID:12363362

  15. Numerical Modeling and In-Situ Observations of the Dynamics of the Solid/Liquid Interface Morphology During Directional Solidification of Alloys

    NASA Technical Reports Server (NTRS)

    Catalina, Adrian V.; Stefanescu, Doru M.; Sen, Subhayu; Curreri, Peter A.; Kaukler, W. F.

    1999-01-01

    The departure from interface planarity and the subsequent evolution to a periodic array of cells or dendrites is a fundamental process that characterizes most microstructures in solidified alloys. The growing demand for high quality alloys and semiconductor crystals requires a precise methodology to predict and subsequently control both the interface morphology and the distribution of impurities, additives, and phases in the grown crystal. Apart from its practical significance, the study of morphological evolution has also been viewed as a means to unearth a general paradigm for pattern formation in nature. A previously developed 2D numerical model for the solid/liquid interface tracking has been further refined and used to simulate the time-evolution of the perturbations on the interface. The dynamics of the local growth velocity, interface undercooling and solute concentration at the interface has been theoretically predicted by means of the numerical model for Al-Cu and Pb-Sn alloys. The model shows that perturbations with a wavelengths, lambda greater than a critical wavelength lambda(sub c) continue to grow in time whereas perturbations with lambda < lambda(sub c) cease to propagate. The model further predicts that under certain conditions perturbation can also propagate along the interface. Comparison of these predictions with existing theories of pattern formation and experimental results will be discussed.

  16. Pseudo-stir bar hollow fiber solid/liquid phase microextraction combined with anodic stripping voltammetry for determination of lead and cadmium in water samples

    PubMed Central

    Es’haghi, Zarrin; Hoseini, Hasan Ali; Mohammadi-Nokhandani, Saeed; Ebrahimi, Javad

    2013-01-01

    A new procedure is presented for the determination of low concentrations of lead and cadmium in water samples. Ligand assisted pseudo-stir bar hollow fiber solid/liquid phase microextraction using sol–gel sorbent reinforced with carbon nanotubes was combined with differential pulse anodic stripping voltammetry for simultaneous determination of cadmium and lead in tap water, and Darongar river water samples. In the present work, differential pulse anodic stripping voltammetry (DPASV) using a hanging mercury drop electrode (HMDE) was used in order to determine the ultra trace level of lead and cadmium ions in real samples. This method is based on accumulation of lead and cadmium ions on the electrode using different ligands; Quinolin-8-ol, 5,7-diiodo quinoline-8-ol, 4,5-diphenyl-1H-imidazole-2(3H)-one and 2-{[2-(2-Hydroxy-ethylamino)-ethylamino]-methyl}-phenol as the complexing agent. The optimized conditions were obtained. The relationship between the peak current versus concentration was linear over the range of 0.05–500 ng mL−1 for Cd (II) and Pb (II). The limits of detection for lead and cadmium were 0.015 ng mL−1 and 0.012 ng mL−1, respectively. Under the optimized conditions, the pre-concentration factors are 2440 and 3710 for Cd (II) and Pb (II) in 5 mL of water sample, respectively. PMID:25685537

  17. Vortex-assisted matrix solid-liquid dispersive microextraction for the analysis of triazole fungicides in cotton seed and honeysuckle by gas chromatography.

    PubMed

    Xue, Jiaying; Li, Huichen; Liu, Fengmao; Jiang, Wenqing; Hou, Fan

    2016-04-01

    A one-step analytical method termed vortex-assisted matrix solid-liquid dispersive microextraction (VA-MSLDME) was developed for the determination of seven triazole fungicides from cotton seed and honeysuckle prior to gas chromatography with electron capture detection. The VA-MSLDME was performed by mixing the matrix, primary secondary amine, acetonitrile, toluene, and water in one single system. The target fungicides in the sample were extracted, cleaned up and preconcentrated simultaneously in the matrix/acetonitrile/water/toluene system. Meanwhile, the interferences were adsorbed by the cleanup adsorbent. The extraction recoveries of the fungicides from the samples varied from 82.9% to 97.8% with relative standard deviations of 4.4-8.5%. The enrichment factors of the analytes ranged from 22 to 47, and the limits of detection were in the range of 0.05-20 μg/kg. The results demonstrated the significant predominance of VA-MSLDME in the analysis of pesticide residues in cotton seed and honeysuckle samples. PMID:26593567

  18. Design and optimization of ultrasound assisted extraction of curcumin as an effective alternative for conventional solid liquid extraction of natural products.

    PubMed

    Mandal, Vivekananda; Dewanjee, Saikat; Sahu, Ranabir; Mandal, Subhash C

    2009-01-01

    The first step in the qualitative and quantitative analysis of medicinal plant constituents is the extraction step. Ideally, an extraction procedure should be exhaustive with respect to the constituents to be analyzed, rapid, simple, and for routine analysis amenable to automation. Usually, the traditional techniques require long extraction times, with more consumption of energy resources and organic solvent, have low efficiency and are often unsafe for thermolabile botanicals. The Taguchi based optimization technique was adapted for the process optimization of ultrasound assisted extraction (UAE) of Curcuma longa to identify the effect of four major factors namely, extraction time, solvent viscosity, grinding degree and solvent volume on the percentage extraction of curcumin. The reproducibility and recovery of the method was also investigated. The efficiency of the new extraction method was then compared with conventional solid liquid extraction procedures. Using this novel method, long hours of conventional Soxhlet extraction were cut down to 70 minutes of UAE with greater reproducibility and recovery. The study clearly shows that this method can be effectively utilized for cutting down long extraction time of botanicals to just a few minutes without the aid of heat. PMID:19370883

  19. Phase relations in the system NaCl-KCl-H2O: V. Thermodynamic-PTX analysis of solid-liquid equilibria at high temperatures and pressures

    USGS Publications Warehouse

    Sterner, S.M.; Chou, I.-Ming; Downs, R.T.; Pitzer, Kenneth S.

    1992-01-01

    The Gibbs energies of mixing for NaCl-KCl binary solids and liquids and solid-saturated NaCl-KCl-H2O ternary liquids were modeled using asymmetric Margules treatments. The coefficients of the expressions were calibrated using an extensive array of binary solvus and solidus data, and both binary and ternary liquidus data. Over the PTX range considered, the system exhibits complete liquid miscibility among all three components and extensive solid solution along the anhydrous binary. Solid-liquid and solid-solid phase equilibria were calculated by using the resulting equations and invoking the equality of chemical potentials of NaCl and KCl between appropriate phases at equilibrium. The equations reproduce the ternary liquidus and predict activity coefficients for NaCl and KCl components in the aqueous liquid under solid-saturation conditions between 673 and 1200 K from vapor saturation up to 5 kbar. In the NaCl-KCl anhydrous binary system, the equations describe phase equilibria and predict activity coefficients of the salt components for all stable compositions of solid and liquid phases between room temperature and 1200 K and from 1 bar to 5 kbar. ?? 1992.

  20. Seeing Below the Drop: Direct Nano-to-microscale Imaging of Complex Interfaces involving Solid, Liquid, and Gas Phases

    NASA Astrophysics Data System (ADS)

    Rykaczewski, Konrad; Landin, Trevan; Walker, Marlon L.; Scott, John Henry J.; Varanasi, Kripa K.

    2012-11-01

    Nanostructured surfaces with special wetting properties have the potential to transform number of industries, including power generation, water desalination, gas and oil production, and microelectronics thermal management. Predicting the wetting properties of these surfaces requires detailed knowledge of the geometry and the composition of the contact volume linking the droplet to the underlying substrate. Surprisingly, a general nano-to-microscale method for direct imaging of such interfaces has previously not been developed. Here we introduce a three dimensional imaging method which resolves this one-hundred-year-old metrology gap in wetting research. Specifically, we demonstrate direct nano-to-microscale imaging of complex fluidic interfaces using cryofixation in combination with cryo-FIB/SEM. We show that application of this method yields previously unattainable quantitative information about the interfacial geometry of water condensed on silicon nanowire forests with hydrophilic and hydrophobic surface termination in the presence or absence of an intermediate water repelling oil. We also discuss imaging artifacts and the advantages of secondary and backscatter electron imaging, Energy Dispersive Spectrometry (EDS), and three dimensional FIB/SEM tomography.

  1. Molecular orientation of enzymes attached to surfaces through defined chemical linkages at the solid-liquid interface.

    PubMed

    Liu, Yuwei; Ogorzalek, Tadeusz L; Yang, Pei; Schroeder, McKenna M; Marsh, E Neil G; Chen, Zhan

    2013-08-28

    The immobilization of enzymes on solid supports is widely used in many applications, including biosensors, antifouling coatings, food packaging materials, and biofuel cells. Enzymes tend to lose their activity when in contact with a support surface, a phenomenon that has been attributed to unfavorable orientation and (partial) unfolding. In this work, specific immobilization of 6-phospho-β-galactosidase (β-Gal) on a self-assembled monolayer (SAM) containing maleimide end groups and oligo(ethylene glycol) spacer segments was achieved through a unique cysteinyl residue. A systematic means to characterize the interfacial orientation of immobilized enzymes has been developed using a combination of sum frequency generation vibrational spectroscopy and attenuated total reflectance FTIR-spectroscopy. The possible orientations of the immobilized β-Gal were determined and found to be well-correlated with the tested activity of β-Gal. This study will impact the development of an increasingly wide range of devices that use surface-immobilized enzymes as integral components with improved functions, better sensitivity, enhanced stability, and longer shelf life. PMID:23883344

  2. Electrical resistance tomography for real-time mapping of the solid-liquid interface in tanks containing optically opaque fluids

    NASA Astrophysics Data System (ADS)

    Madupu, Amar; Mazumdar, Anindra; Zhang, Jinsong; Roelant, David; Srivastava, Rajiv

    2005-03-01

    The visualization of settled solid layers in vessels have many applications, of interest here is for facilitating the efficient retrieval of high-level radioactive waste (HLW) from underground storage tanks at Department of Energy sites. Visualization of the solids interface with opaque liquid above can"t be accomplished by regular optical imaging methods and hence our interest in using Electrical Resistance Tomography (ERT). The ideal arrangement for 3-D ERT imaging inside tanks is to use a multiple ring electrode system, which is complex and expensive. This research describes ERT imaging done with a single linear array as a benchmark study to ascertain the viability of its imaging of the interface. Experiments focused upon systematic analysis of many ERT tomograms of two simple settled solids layers (horizontal, 30o) using pulverized kaolin clay (10μdia) and water. Visualization was done using commercial ERT software. Injection current and electrode orientation were the two system parameters varied and analyzed. Reproducibility, accuracy and reliability of this ERT system will be presented.

  3. Mass transfer properties of nanoconfined fluids at solid-liquid interfaces: from atomistic simulations to continuum models

    NASA Astrophysics Data System (ADS)

    Morciano, Matteo; Fasano, Matteo; Nold, Andreas; Correia Braga, Carlos; Yatsyshin, Petr; Sibley, David; Goddard, Benjamin; Chiavazzo, Eliodoro; Asinari, Pietro; Kalliadasis, Serafim; multi-Scale ModeLing Laboratory Team; Complex Multiphase Systems Team

    2015-11-01

    At the nanoscale, traditional continuum models are not sufficient to describe fluid flow. For example, the no-slip assumption may not be valid for nanoscale flows, where interface effects dominate transport phenomena. Hence, classic boundary conditions should take into account possible interplays between fluid velocity, shear stress, surface chemistry and roughness. Unlike hydrodynamics, in molecular dynamics (MD), the boundary conditions are not specified a priori but arise naturally from computations. Here, mass transfer properties for a Lennard-Jones fluid confined in a nanochannel are studied by MD. Density, stress and velocity profiles within the fluid are evaluated with different nanoconfined conditions, shear rates and surface hydrophilicity. Our results show a strong anisotropic behavior of fluid properties along the channel section. Shear rates and velocity profiles allow calculating the spatial distribution of viscosity along the channel. We also observe that hydrophilic surfaces lead to increased viscosity. Our findings may have a potential impact on the design of nanofluidic devices for either engineering or biomedical applications.

  4. Reliability study of Au-in solid-liquid interdiffusion bonding for GaN-based vertical LED packaging

    NASA Astrophysics Data System (ADS)

    Sung, Ho-Kun; Wang, Cong; Kim, Nam-Young

    2015-12-01

    An In-rich Au-In bonding system has been developed to transfer vertical light-emitting diodes (VLEDs) from a sapphire to a graphite substrate and enable them to survive under n-ohmic contact treatment at 350 °C. The bonding temperature is 210 °C, and three intermetallic compounds are detected: AuIn, AuIn2, and γ phase. As a result, the remelting temperature increases beyond the theoretical value of 450 °C according to the Au-In binary phase diagram. In fact, reliability testing showed that joints obtained by rapid thermal annealing at 400 °C for 1 min survived whereas those obtained at 500 °C for 1 min failed. Finally, a GaN-based blue VLED was transferred to the graphite substrate by means of the proposed bonding method, and its average light output power was measured to be 386.6 mW (@350 mA) after n-ohmic contact treatment. This wafer-level bonding technique also shows excellent potential for high-temperature packing applications.

  5. BEHAVIOR OF SURFACTANT MIXTURES AT SOLID/LIQUID AND OIL/LIQUID INTERFACES IN CHEMICAL FLOODING SYSTEMS

    SciTech Connect

    Prof. P. Somasundaran

    2002-09-30

    The aim of the project is to develop and evaluate efficient novel surfactant mixtures for enhanced oil recovery. Surfactant loss by adsorption or precipitation depends to a great extent on the type of surfactant complexes and aggregates formed. Such information as well as techniques to generate the information is lacking currently particularly for surfactant mixtures and surfactant/polymer systems. A novel analytical centrifuge application is explored during the last period to generate information on structures-performance relationship for different surfactant aggregates in solution and, in turn, at interfaces. To use analytical untracentrifuge for surfactant mixtures, information on partial specific volumes of single surfactants and their mixtures is required. Towards this purpose, surface tension and density measurements were performed to determine critical micellar concentrations (cmc), partial specific volumes of n-dodecyl-{beta}-Dmaltoside (DM), nonyl phenol ethoxylated decyl ether (NP-10) and their 1:1 mixtures at 25 C. Durchschlag's theoretical calculation method was adopted to calculate the partial specific volumes. Effects of temperature and mixing, as well as methods used for estimation on micellization and partial specific volumes were studied during the current period. Surface tension results revealed no interaction between the two surfactants in mixed micelles. Partial specific volume measurements also indicated no interaction in mixed micelles. Maximum adsorption density, area per molecule and free energy of micellization were also calculated. Partial specific volumes were estimated by two experimental methods: d{sub {rho}}/dc and V{sub {sigma}}. The difference between the results of using the two methods is within 0.5% deviation. It was found that the partial specific volume is concentration dependent and sensitive to changes in temperature. The information generated in this study will be used for the study of surfactant aggregate mass distribution

  6. BEHAVIOR OF SURFACTANT MIXTURE AT SOLID/LIQUID AND OIL/LIQUID INTERFACE IN CHEMICAL FLOODING SYSTEMS

    SciTech Connect

    Prof. P. Somasundaran

    2002-03-01

    The aim of the project is to develop and evaluate efficient novel surfactant mixtures for enhanced oil recovery. Preliminary ultra-filtration tests suggest that two kinds of micelles may exist in binary surfactant mixtures at different concentrations. Due to the important role played in interfacial processes by micelles as determined by their structures, focus of the current work is on the delineation of the relationship between such aggregate structures and chemical compositions of the surfactants. A novel analytical centrifuge application is explored to generate information on structures of different surfactants aggregates. In this report, optical systems, typical output of the analytical ultracentrifuge results and four basic experiments are discussed. Initial sedimentation velocity investigations were conducted using nonyl phenol ethoxylated decyl ether (NP-10) to choose the best analytical protocol, calculate the partial specific volume and obtain information on sedimentation coefficient, aggregation mass of micelles. The partial specific volume was calculated to be 0.920. Four softwares: Optima{trademark} XL-A/XL-I data analysis software, DCDT+, Svedberg and SEDFIT, were compared for the analysis of sedimentation velocity experimental data. The sedimentation coefficient and aggregation number of NP-10 micelles obtained using the first three softwares at 25 C are 209, 127, and 111, respectively. The last one is closest to the result from Light Scattering. The reason for the differences in numbers obtained using the three softwares is discussed. Based on these tests, Svedberg and SEDFIT analysis are chosen for further studies. This approach using the analytical ultracentrifugation offers an unprecedented opportunity now to obtain important information on mixed micelles and their role in interfacial processes.

  7. Interdire aux enfants et aux adolescents de moins de 18 ans l’accès aux établissements commerciaux de bronzage

    PubMed Central

    Taddeo, Danielle; Stanwick, Richard

    2012-01-01

    RÉSUMÉ Le nombre de mélanomes cutanés malins a plus que triplé depuis 35 ans. Puisque les dommages sont cumulatifs, l’exposition aux rayonnements ultraviolets tôt dans la vie accroît le risque, qui augmente davantage avec l’utilisation de sources artificielles de rayonnements ultraviolets. Il peut falloir des années pour évaluer les répercussions et l’étendue complètes des dommages causés par le bronzage artificiel à longueur d’année, compte tenu de la longue période de latence de la plupart des cancers de la peau. Les adolescents fréquentent souvent les salons de bronzage, les filles s’y rendant davantage et de manière soutenue. L’industrie du bronzage conteste la classification de cancérigène physique de groupe 1 qu’attribuent au bronzage artificiel l’Organisation mondiale de la santé et le Centre international de recherche sur le cancer. Les salons de bronzage cherchent à établir et à maintenir une clientèle chez les adolescents. Par conséquent, la Société canadienne de pédiatrie s’ajoute à d’autres organismes de santé réputés pour appuyer l’interdiction des établissements commerciaux de bronzage aux enfants et adolescents de moins de 18 ans.

  8. Membrane filtration of the liquid fraction from a solid-liquid separator for swine manure using a cationic polymer as flocculating agent.

    PubMed

    Masse, L; Mondor, M; Dubreuil, J

    2013-01-01

    The liquid fraction from a solid-liquid separator for swine manure, which used a cationic polymer to promote particle flocculation, was processed by one nanofiltration and two reverse osmosis spiral-wound membranes. Eight different liquid fraction batches (750 to 1750 L) were concentrated at volumetric concentration ratios (VCRs, initial to final volumes) ranging from 2.3 to 4.2. Membrane fouling intensity was highly variable, as water flux recovery after concentration cycles ranged from 13% to 88%. The most severe fouling was caused by a liquid fraction that had relatively low suspended solids (SS) (774 mg/L) and was concentrated at a low VCR of 2.6. Raw manure collected the same day also contained low SS, suggesting that fewer sites were available for polymer adsorption and thus more polymer remained in the liquid. However, because of the high opacity of the samples, residual polymer could not be detected in any feed or concentrate samples. Fouling was not totally irreversible as over 97% of membrane flux could be recovered by cleaning with acidic and alkaline solutions. Further tests with spiked liquid fractions indicated that fouling due to residual polymer in solution started to occur at a polymer concentration of 3 and 11 mg/L in initial and concentrated effluents, respectively. If a cationic polymer is used to pretreat manure, the amount of added polymer would have to be closely related to SS content as opposed to manure volume, in order to leave very little residual polymer in solution. PMID:23837317

  9. High temperature investigation of the solid/liquid transition in the PuO2-UO2-ZrO2 system

    NASA Astrophysics Data System (ADS)

    Quaini, A.; Guéneau, C.; Gossé, S.; Sundman, B.; Manara, D.; Smith, A. L.; Bottomley, D.; Lajarge, P.; Ernstberger, M.; Hodaj, F.

    2015-12-01

    The solid/liquid transitions in the quaternary U-Pu-Zr-O system are of great interest for the analysis of core meltdown accidents in Pressurised Water Reactors (PWR) fuelled with uranium-dioxide and MOX. During a severe accident the Zr-based cladding can become completely oxidised due to the interaction with the oxide fuel and the water coolant. In this framework, the present analysis is focused on the pseudo-ternary system UO2-PuO2-ZrO2. The melting/solidification behaviour of five pseudo-ternary and one pseudo-binary ((PuO2)0.50(ZrO2)0.50) compositions have been investigated experimentally by a laser heating method under pre-set atmospheres. The effects of an oxidising or reducing atmosphere on the observed melting/freezing temperatures, as well as the amount of UO2 in the sample, have been clearly identified for the different compositions. The oxygen-to-metal ratio is a key parameter affecting the melting/freezing temperature because of incongruent vaporisation effects. In parallel, a detailed thermodynamic model for the UO2-PuO2-ZrO2 system has been developed using the CALPHAD method, and thermodynamic calculations have been performed to interpret the present laser heating results, as well as the high temperature behaviour of the cubic (Pu,U,Zr)O2±x-c mixed oxide phase. A good agreement was obtained between the calculated and experimental data points. This work enables an improved understanding of the major factors relevant to severe accident in nuclear reactors.

  10. Determination of caffeoylquinic acids in feed and related products by focused ultrasound solid-liquid extraction and ultra-high performance liquid chromatography-mass spectrometry.

    PubMed

    Tena, M T; Martínez-Moral, M P; Cardozo, P W

    2015-06-26

    A method to determine caffeoylquinic acids (CQAs) in three sources (herbal extract, feed additive and finished feed) using for the first time focused ultrasound solid-liquid extraction (FUSLE) followed by ultra-high performance liquid chromatography (UPLC) coupled to quadrupole-time of flight mass spectrometry is presented. Pressurized liquid extraction (PLE) was also tested as extraction technique but it was discarded because cynarin was not stable under temperature values used in PLE. The separation of the CQAs isomers was carried out in only seven minutes. FUSLE variables such as extraction solvent, power and time were optimized by a central composite design. Under optimal conditions, FUSLE extraction was performed with 8mL of an 83:17 methanol-water mixture for 30s at a power of 60%. Only two extraction steps were found necessary to recover analytes quantitatively. Sensitivity, linearity, accuracy and precision were established. Matrix effect was studied for each type of sample. It was not detected for mono-CQAs, whereas the cynarin signal was strongly decreased due to ionization suppression in presence of matrix components; so the quantification by standard addition was mandatory for the determination of di-caffeoylquinic acids. Finally, the method was applied to the analysis of herbal extracts, feed additives and finished feed. In all samples, chlorogenic acid was the predominant CQA, followed by criptochlorogenic acid, neochlorogenic acid and cynarin. The method allows an efficient determination of chlorogenic acid with good recovery rates. Therefore, it may be used for screening of raw material and for process and quality control in feed manufacture. PMID:25981290

  11. Study of solid/liquid and solid/gas interfaces in Cu-isoleucine complex by surface X-ray diffraction

    NASA Astrophysics Data System (ADS)

    Ferrer, Pilar; Rubio-Zuazo, Juan; Castro, German R.

    2013-02-01

    The enzymes could be understood like structures formed by amino acids bonded with metals, which act as active sites. The research on the coordination of metal-amino acid complexes will bring light on the behavior of metal enzymes, due to the close relation existing between the atomic structure and the functionality. The Cu-isoleucine bond is considered as a good model system to attain a better insight into the characteristics of naturally occurring copper metalloproteins. The surface structure of metal-amino acid complex could be considered as a more realistic model for real systems under biologic working conditions, since the molecular packing is decreased. In the surface, the structural constrains are reduced, keeping the structural capability of surface complex to change as a function of the surrounding environment. In this work, we present a surface X-ray diffraction study on Cu-isoleucine complex under different ambient conditions. Cu(Ile)2 crystals of about 5 mm × 5 mm × 1 mm have been growth, by seeding method in a supersaturated solution, presenting a surface of high quality. The sample for the surface diffraction study was mounted on a cell specially designed for solid/liquid or solid/gas interface analysis. The Cu-isoleucine crystal was measured under a protective dry N2 gas flow and in contact with a saturated metal amino acid solution. The bulk and the surface signals were compared, showing different atomic structures. In both cases, from surface diffraction data, it is observed that the atomic structure of the top layer undergoes a clear structural deformation. A non-uniform surface relaxation is observed producing an inhomogeneous displacement of the surface atoms towards the surface normal.

  12. The coupling of surface charge and boundary slip at the solid-liquid interface and their combined effect on fluid drag: A review.

    PubMed

    Jing, Dalei; Bhushan, Bharat

    2015-09-15

    Fluid drag of micro/nano fluidic systems has inspired wide scientific interest. Surface charge and boundary slip at the solid-liquid interface are believed to affect fluid drag. This review summarizes the recent studies on the coupling of surface charge and slip, and their combined effect on fluid drag at micro/nano scale. The effect of pH on surface charge of borosilicate glass and silica surfaces in deionized (DI) water and saline solution is discussed using a method based on colloidal probe atomic force microscopy (AFM). The boundary slip of various oil-solid interfaces are discussed for samples with different degrees of oleophobicity prepared by nanoparticle-binder system. By changing the pH of solution or applying an electric field, effect of surface charge on slip of a smooth hydrophobic octadecyltrichlorosilane (OTS) in DI water and saline solution is studied. A theoretical model incorporating the coupling relationship between surface charge and slip is used to discuss the combined effect of surface charge-induced electric double layer (EDL) and slip on fluid drag of pressure-driven flow in a one-dimensional parallel-plates microchannel. A theoretical method is used to reduce the fluid drag. The studies show that the increasing magnitude of surface charge density leads to a decrease in slip length. The surface charge results in a larger fluid drag, and the coupling of surface charge and slip can further increase the fluid drag. Surface charge-induced EDLs with asymmetric zeta potentials can effectively reduce the fluid drag. PMID:26021432

  13. Determination of endocrine disrupting compounds in fish liver, brain, and muscle using focused ultrasound solid-liquid extraction and dispersive solid phase extraction as clean-up strategy.

    PubMed

    Ros, Oihana; Vallejo, Asier; Olivares, Maitane; Etxebarria, Nestor; Prieto, Ailette

    2016-08-01

    This study describes a new method for the simultaneous extraction of several endocrine disrupting compounds, including alkylphenols (APs), estrogen, bisphenol-A (BPA) and one phthalate metabolite (mono-2-ethylhexyl ester, MEHP) in fish liver, brain, and muscle. Parameters affecting the extraction (extraction solvent and temperature) and the clean-up (dispersive phase nature and amount) steps were evaluated. The extraction was performed by means of focused ultrasound solid-liquid extraction (FUSLE) using 10 mL of n-hexane:acetone (50:50, v/v) for 5 min at ~0 °C, and the clean-up was done by means of dispersive solid phase extraction (dSPE) using 100 mg of ENVI-CARB and 100 mg of MgSO4 for the cleaning of brain and muscle extracts together with 100 mg of PSA in the case of liver extracts. Good apparent recoveries were obtained in the case of liver (62-132 %), brain (66-120 %), and muscle (74-129 %), relative standard deviation (RSD%) was always below 26 %, and the method detection limits (MDLs) were at low ng/g level. The developed method was applied to fish captured in Urdaibai estuary (Bay of Biscay) in December 2015, and the concentrations obtained were in the range MDL-1115 ng/g in brain, MDL-962 ng/g in muscle, and MDL-672 ng/g in liver. In general, the highest concentrations were measured in liver, followed by brain and muscle. In addition, diethylstilbestrol was only detected in fish brain. Graphical Abstract MS method scheme for the/MS method scheme for the determination of EDCs in fish liver, brain and muscle. PMID:27342793

  14. Enhanced biotransformation of 2-phenylethanol with ethanol oxidation in a solid-liquid two-phase system by active dry yeast.

    PubMed

    Rong, Shaofeng; Ding, Baomei; Zhang, Xiaoli; Zheng, Xuesong; Wang, Yifei

    2011-11-01

    2-Phenylethanol (2-PE) can be produced from L: -phenylalanine (L: -Phe) with the oxidation degradation of ethanol by active dry yeast. In this study, the catalysis effect of ethanol on biotransforming L: -Phe into 2-PE by yeast was evaluated and optimized. The results indicated that increasing ethanol concentration was beneficial for enhancing 2-PE concentration but lowered the 2-PE productivity. Initial ethanol concentration above 25 g/l could strongly inhibit the 2-PE production. To obtain 2-PE with desirable concentrations with an economical operation mode, three fed-batch biotransformation operation methods using ethanol or/and glucose were carried out in a solid-liquid two-phase system. When using ethanol alone with the initial concentration of 10 g/l, the total concentration and overall productivity of 2-PE were 7.6 g/l and 0.065 g l(-1) h(-1), respectively. Furthermore, an experiment with controlled glucose solely (higher than 2 g/l) was finished. In this case, phenylacetaldehyde (PA) was detected along with ethanol accumulation, suggesting that reaction of PA → 2-PE in Ehrlich pathway was inhibited. To further enhance 2-PE production by using glucose only, a novel operation strategy to simultaneously control rates of glucose glycolysis and ethanol oxidative degradation with the aid of ISPR techniques was developed. With this strategy, 2-PE concentration and yield based on glucose consumption reached a higher level of 14.8 g/l and 0.12 g-PE/g-glucose, respectively, and these are the highest values reported up to date with the fed-batch biotransformation operation mode. PMID:21910022

  15. CO2 sequestration using waste concrete and anorthosite tailings by direct mineral carbonation in gas-solid-liquid and gas-solid routes.

    PubMed

    Ben Ghacham, Alia; Cecchi, Emmanuelle; Pasquier, Louis-César; Blais, Jean-François; Mercier, Guy

    2015-11-01

    Mineral carbonation (MC) represents a promising alternative for sequestering CO2. In this work, the CO2 sequestration capacity of the available calcium-bearing materials waste concrete and anorthosite tailings is assessed in gas-solid-liquid and gas-solid routes using 18.2% flue CO2 gas. The objective is to screen for a better potential residue and phase route and as the ultimate purpose to develop a cost-effective process. The results indicate the possibility of removing 66% from inlet CO2 using waste concrete for the aqueous route. However, the results that were obtained with the carbonation of anorthosite were less significant, with 34% as the maximal percentage of CO2 removal. The difference in terms of reactivity could be explained by the accessibility to calcium. In fact, anorthosite presents a framework structure wherein the calcium is trapped, which could slow the calcium dissolution into the aqueous phase compared to the concrete sample, where calcium can more easily leach. In the other part of the study concerning gas-solid carbonation, the results of CO2 removal did not exceed 15%, which is not economically interesting for scaling up the process. The results obtained with waste concrete samples in aqueous phase are interesting. In fact, 34.6% of the introduced CO2 is converted into carbonate after 15 min of contact with the gas without chemical additives and at a relatively low gas pressure. Research on the optimization of the aqueous process using waste concrete should be performed to enhance the reaction rate and to develop a cost-effective process. PMID:26292776

  16. Simultaneous multi-mycotoxin determination in nutmeg by ultrasound-assisted solid-liquid extraction and immunoaffinity column clean-up coupled with liquid chromatography and on-line post-column photochemical derivatization-fluorescence detection.

    PubMed

    Kong, Wei-Jun; Liu, Shu-Yu; Qiu, Feng; Xiao, Xiao-He; Yang, Mei-Hua

    2013-05-01

    A simple and sensitive analytical method based on ultrasound-assisted solid-liquid extraction and immunoaffinity column clean-up coupled with high performance liquid chromatography and on-line post-column photochemical derivatization-fluorescence detection (USLE-IAC-HPLC-PCD-FLD) has been developed for simultaneous multi-mycotoxin determination of aflatoxins B1, B2, G1, G2 (AFB1, AFB2, AFG1, AFG2) and ochratoxin A (OTA) in 13 edible and medicinal nutmeg samples marketed in China. AFs and OTA were extracted from nutmeg samples by ultrasonication using a methanol : water (80 : 20, v/v) solution, followed by an IAC clean-up step. Different USL extraction conditions, pre-processing ways for nutmeg sample and clean-up columns for mycotoxins, as well as HPLC-PCD-FLD parameters (mobile phase, column temperature, elution procedure, excitation and emission wavelengths) were optimized. This method, which was appraised for analyzing nutmeg samples, showed satisfactory results with reference to limits of detection (LODs) (from 0.02 to 0.25 μg kg(-1)), limits of quantification (LOQs) (from 0.06 to 0.8 μg kg(-1)), linear ranges (up to 30 ng mL(-1) for AFB1, AFG1 and OTA and 9 ng mL(-1) for AFB2 and AFG2), intra- and inter-day variability (all <2%) and average recoveries (from 79.6 to 90.8% for AFs and from 93.6 to 97.3% for OTA, respectively). The results of the application of developed method in nutmeg samples have elucidated that four samples were detected with contamination of AFs and one with OTA. AFB1 was the most frequently found mycotoxin in 30.8% of nutmeg samples at contamination levels of 0.73-16.31 μg kg(-1). At least two different mycotoxins were co-occurred in three samples, and three AFs were simultaneously detected in one sample. PMID:23486692

  17. Maladies reliées aux loisirs aquatiques

    PubMed Central

    Sanborn, Margaret; Takaro, Tim

    2013-01-01

    Résumé Objectif Passer en revue les facteurs de risque, la prise en charge et la prévention des maladies reliées aux loisirs aquatiques en pratique familiale. Sources des données Des articles originaux et de synthèse entre janvier 1998 et février 2012 ont été identifiés à l’aide de PubMed et des expressions de recherche en anglais water-related illness, recreational water illness et swimmer illness. Message principal Il y a un risque de 3 % à 8 % de maladies gastrointestinales (MGI) après la baignade. Les groupes à risque élevé de MGI sont les enfants de moins de 5 ans, surtout s’ils n’ont pas été vaccinés contre le rotavirus, les personnes âgées et les patients immunodéficients. Les enfants sont à plus grand risque parce qu’ils avalent plus d’eau quand ils nagent, restent dans l’eau plus longtemps et jouent dans l’eau peu profonde et le sable qui sont plus contaminés. Les adeptes des sports dans lesquels le contact avec l’eau est abondant comme le triathlon et le surf cerf-volant sont aussi à risque élevé et même ceux qui s’adonnent à des activités impliquant un contact partiel avec l’eau comme la navigation de plaisance et la pêche ont un risque de 40 % à 50 % fois plus grand de MGI par rapport à ceux qui ne pratiquent pas de sports aquatiques. Il y a lieu de faire une culture des selles quand on soupçonne une maladie reliée aux loisirs aquatiques et l’échelle clinique de la déshydratation est utile pour l’évaluation des besoins de traitement chez les enfants affectés. Conclusion Les maladies reliées aux loisirs aquatiques est la principale cause de MGI durant la saison des baignades. La reconnaissance que la baignade est une source importante de maladies peut aider à prévenir les cas récurrents et secondaires. On recommande fortement le vaccin contre le rotavirus chez les enfants qui se baignent souvent.

  18. A comparison of bacterial populations in enhanced biological phosphorus removal processes using membrane filtration or gravity sedimentation for solids-liquid separation.

    PubMed

    Hall, Eric R; Monti, Alessandro; Mohn, William W

    2010-05-01

    CEBPR system also revealed many uncultured organisms that have not been well characterized. The study demonstrated that a simple replacement of a secondary clarifier with membrane solids-liquid separation is sufficient to shift the composition of an activated sludge microbial community significantly. PMID:20189214

  19. Constitutive auxin response in Physcomitrella reveals complex interactions between Aux/IAA and ARF proteins

    PubMed Central

    Lavy, Meirav; Prigge, Michael J; Tao, Sibo; Shain, Stephanie; Kuo, April; Kirchsteiger, Kerstin; Estelle, Mark

    2016-01-01

    The coordinated action of the auxin-sensitive Aux/IAA transcriptional repressors and ARF transcription factors produces complex gene-regulatory networks in plants. Despite their importance, our knowledge of these two protein families is largely based on analysis of stabilized forms of the Aux/IAAs, and studies of a subgroup of ARFs that function as transcriptional activators. To understand how auxin regulates gene expression we generated a Physcomitrella patens line that completely lacks Aux/IAAs. Loss of the repressors causes massive changes in transcription with misregulation of over a third of the annotated genes. Further, we find that the aux/iaa mutant is blind to auxin indicating that auxin regulation of transcription occurs exclusively through Aux/IAA function. We used the aux/iaa mutant as a simplified platform for studies of ARF function and demonstrate that repressing ARFs regulate auxin-induced genes and fine-tune their expression. Further the repressing ARFs coordinate gene induction jointly with activating ARFs and the Aux/IAAs. DOI: http://dx.doi.org/10.7554/eLife.13325.001 PMID:27247276

  20. Constitutive auxin response in Physcomitrella reveals complex interactions between Aux/IAA and ARF proteins.

    PubMed

    Lavy, Meirav; Prigge, Michael J; Tao, Sibo; Shain, Stephanie; Kuo, April; Kirchsteiger, Kerstin; Estelle, Mark

    2016-01-01

    The coordinated action of the auxin-sensitive Aux/IAA transcriptional repressors and ARF transcription factors produces complex gene-regulatory networks in plants. Despite their importance, our knowledge of these two protein families is largely based on analysis of stabilized forms of the Aux/IAAs, and studies of a subgroup of ARFs that function as transcriptional activators. To understand how auxin regulates gene expression we generated a Physcomitrella patens line that completely lacks Aux/IAAs. Loss of the repressors causes massive changes in transcription with misregulation of over a third of the annotated genes. Further, we find that the aux/iaa mutant is blind to auxin indicating that auxin regulation of transcription occurs exclusively through Aux/IAA function. We used the aux/iaa mutant as a simplified platform for studies of ARF function and demonstrate that repressing ARFs regulate auxin-induced genes and fine-tune their expression. Further the repressing ARFs coordinate gene induction jointly with activating ARFs and the Aux/IAAs. PMID:27247276

  1. Preliminary paleogeographic reconstruction of the Illinois basin during deposition of the Mississippian Aux Vases Formation: Implications for hydrocarbon recovery

    SciTech Connect

    Cole, R.D. )

    1991-03-01

    Extensive outcrop investigation and selective subsurface study allow definition of Illinois basin paleogeography during deposition of the Mississippian (Valmeyeran-Meramecian) Aux Vases Formation. The results incorporate an integrated approach utilizing field observations and petrographic analysis, wireline logs, subsurface maps, and cores. The Aux Vases Formation depositional system has been determined to be composed of subtidal to intertidal facies. Depositional facies in outcrop are based on rock body geometries, sedimentary structure assemblages, paleocurrent analysis, paleontology of body and trace fossils, facies relationships, and petrography. Depositional facies determined from subsurface data are based on correlation of lithologic interpretations from wireline logs, sand body geometries form isopach maps, and petrography. Specific depositional facies observed in outcrop and core and inferred from wireline logs and isopach maps are offshore bars and tidal channel complexes, extensive subtidal to lower intertidal, ripple-laminated, fine-grained quartzose sandstone. Carbonate facies occur as subtidal grainstones at or near the base of a sequence, or as high energy deposits which have been tidally reworked. This depositional system produces reservoir heterogeneities that complicate efficient hydrocarbon recovery. This diverse facies architecture is modified by tectonic and diagenetic overprinting, further segregating potential producing zones. To significantly improve recovery efficiency, predictions regarding compartmentalization can be used prior to designing a drilling program, an infill drilling program, or an application of enhanced recovery techniques.

  2. Protein-protein interaction and gene co-expression maps of ARFs and Aux/IAAs in Arabidopsis

    PubMed Central

    Piya, Sarbottam; Shrestha, Sandesh K.; Binder, Brad; Stewart, C. Neal; Hewezi, Tarek

    2014-01-01

    The phytohormone auxin regulates nearly all aspects of plant growth and development. Based on the current model in Arabidopsis thaliana, Auxin/indole-3-acetic acid (Aux/IAA) proteins repress auxin-inducible genes by inhibiting auxin response transcription factors (ARFs). Experimental evidence suggests that heterodimerization between Aux/IAA and ARF proteins are related to their unique biological functions. The objective of this study was to generate the Aux/IAA-ARF protein-protein interaction map using full length sequences and locate the interacting protein pairs to specific gene co-expression networks in order to define tissue-specific responses of the Aux/IAA-ARF interactome. Pairwise interactions between 19 ARFs and 29 Aux/IAAs resulted in the identification of 213 specific interactions of which 79 interactions were previously unknown. The incorporation of co-expression profiles with protein-protein interaction data revealed a strong correlation of gene co-expression for 70% of the ARF-Aux/IAA interacting pairs in at least one tissue/organ, indicative of the biological significance of these interactions. Importantly, ARF4-8 and 19, which were found to interact with almost all Aux-Aux/IAA showed broad co-expression relationships with Aux/IAA genes, thus, formed the central hubs of the co-expression network. Our analyses provide new insights into the biological significance of ARF-Aux/IAA associations in the morphogenesis and development of various plant tissues and organs. PMID:25566309

  3. Extraction and preconcentration of tylosin from milk samples through functionalized TiO₂ nanoparticles reinforced with a hollow fiber membrane as a novel solid/liquid-phase microextraction technique.

    PubMed

    Sehati, Negar; Dalali, Nasser; Soltanpour, Shahla; Dorraji, Mir Saeed Seyed

    2014-08-01

    The aim of this study was to introduce a novel, simple, and highly sensitive preparation method for determination of tylosin in different milk samples. In the so-called functionalized TiO2 hollow fiber solid/liquid-phase microextraction method, the acceptor phase is functionalized TiO2 nanoparticles that are dispersed in the organic solvent and held in the pores and lumen of a porous polypropylene hollow fiber membrane. An effective functionalization of TiO2 nanoparticles has been done in the presence of aqueous H2 O2 and a mild acidic ambient under UV irradiation. This novel extraction method showed excellent extraction efficiency and a high enrichment factor (540.2) in comparison with conventional hollow fiber liquid-phase microextraction. All the experiments were monitored at λmax = 284 nm using a simple double beam UV-visible spectrophotometer. A Taguchi orthogonal array experimental design with an OA16 (4(5) ) matrix was employed to optimize the factors affecting the efficiency of hollow fiber solid/liquid-phase microextraction such as pH, stirring rate, salt addition, extraction time, and the volume of donor phase. This developed method was successfully applied for the separation and determination of tylosin in milk samples with a linear concentration range of 0.51-7000 μg/L (r(2) = 0.991) and 0.21 μg/L as the limit of detection. PMID:24890459

  4. Canalization of auxin flow by Aux/IAA-ARF-dependent feedback regulation of PIN polarity.

    PubMed

    Sauer, Michael; Balla, Jozef; Luschnig, Christian; Wisniewska, Justyna; Reinöhl, Vilém; Friml, Jirí; Benková, Eva

    2006-10-15

    Plant development is characterized by a profound ability to regenerate and form tissues with new axes of polarity. An unsolved question concerns how the position within a tissue and cues from neighboring cells are integrated to specify the polarity of individual cells. The canalization hypothesis proposes a feedback effect of the phytohormone auxin on the directionality of intercellular auxin flow as a means to polarize tissues. Here we identify a cellular and molecular mechanism for canalization. Local auxin application, wounding, or auxin accumulation during de novo organ formation lead to rearrangements in the subcellular polar localization of PIN auxin transport components. This auxin effect on PIN polarity is cell-specific, does not depend on PIN transcription, and involves the Aux/IAA-ARF (indole-3-acetic acid-auxin response factor) signaling pathway. Our data suggest that auxin acts as polarizing cue, which links individual cell polarity with tissue and organ polarity through control of PIN polar targeting. This feedback regulation provides a conceptual framework for polarization during multiple regenerative and patterning processes in plants. PMID:17043314

  5. Symetries et integrabilite des equations aux differences finies

    NASA Astrophysics Data System (ADS)

    Lafortune, Stephane

    2000-09-01

    La présente thèse porte sur l'étude des symétries et des propriétés d'intégrabilité des équations aux différences finies. Dans le chapitre 1, le groupe de symétrie ponctuelle d'un système couplé à deux équations différentielles aux différences est étudié. On montre que dans certains cas, la dimension du groupe peut être infinie. Les équations peuvent décrire l'interaction de deux longues chaînes moléculaires, chacune étant composée d'atomes d'un même type. Dans le chapitre 2, une classe de théories de champs avec interaction exponentielle est introduite. L'interaction dépend de deux matrices de ``couplage'' et est suffisamment générale pour inclure toutes les théories de champs de Toda existant dans la littérature. Les symétries de Lie ponctuelles sont obtenues pour les cas où l'on a un nombre fini, infini ou semi-infini de champs. Une attention spéciale est accordée à la présence de l'invariance conforme. Dans le chapitre 3, nous procédons à la classification et à l'étude d'équations linéarisables. Nous examinons tout d'abord l'équation de Gambier continue qui contient, comme réductions, toutes les équations de deuxième ordre intégrables par linéarisation. Nous introduisons par la suite la forme discrète de cette équation et obtenons les conditions d'intégrabilité à l'aide du confinement des singularités. Nous étudions aussi les différentes réductions du cas discret. De plus, nous obtenons des transformations de Schlesinger pour les équations de Gambier discrète et continue. Dans la dernière partie du chapitre, nous étudions une famille d'équations discrètes du deuxième ordre incluant des équations résolubles par linéarisation. Plusieurs cas intégrables sont obtenus. Dans le cas discret, l'étude de l'intégrabilité est faite à l'aide du confinement des singularités. Dans le chapitre 4, nous étudions un autre critère d'intégrabilité: l'entropie algébrique. Nous montrons que les r

  6. Expression of PIN and AUX1 genes encoding putative carrier proteins for auxin polar transport in etiolated pea epicotyls [correction of epicotyles] under simulated microgravity conditions on a three-dimensional clinostat.

    PubMed

    Hoshino, Tomoki; Hitotsubashi, Reiko; Miyamoto, Kensuke; Tanimoto, Eiichi; Ueda, Junichi

    2003-10-01

    Etiolated pea (Pisum sativum L. cv. Alaska) seedlings grown under simulated microgravity conditions on a 3-dimensional clinostat showed automorphosis-like growth and development similar to that observed in true microgravity conditions in space. Application of inhibitors of auxin polar transport phenocopied automorphosis-like growth on 1 g conditions, suggesting that automorophosis is closely related to auxin polar transport. Strenuous efforts to know the relationships between automorphosis and auxin polar transport in pea seedlings at molecular bases resulted in successful identification of PsPIN2 and PsAUX1 encoding putative auxin efflux and influx carrier protein, respectively. Significantly high levels in homology were found on nucleotide and deduced amino acid sequences among PsPIN2, PsPIN1 and AtPINs, and between PsAUX1 and AtAUX1. Expression of PsPIN1 and PsAUX1 genes in etiolated pea seedlings grown on the clinostat were substantially affected, but that of PsPIN2 was not. Roles of these genes in auxin polar transport and automorphosis of etiolated pea seedlings are also described. PMID:14676360

  7. A water-soluble gadolinium metallofullerenol: facile preparation, magnetic properties and magnetic resonance imaging application.

    PubMed

    Li, Jie; Wang, Taishan; Feng, Yongqiang; Zhang, Ying; Zhen, Mingming; Shu, Chunying; Jiang, Li; Wang, Yuqing; Wang, Chunru

    2016-06-01

    A new water-soluble gadolinium metallofullerenol was prepared through a solid-liquid reaction. It was characterized to have an enhanced effective magnetic moment, and improved T1-weighted relaxivity and magnetic resonance imaging performance in the liver. This material prepared by a facile method has wide application as a contrast agent and biological medicine. PMID:27064096

  8. Evidence supporting an intentional Neandertal burial at La Chapelle-aux-Saints

    PubMed Central

    Rendu, William; Beauval, Cédric; Crevecoeur, Isabelle; Bayle, Priscilla; Balzeau, Antoine; Bismuth, Thierry; Bourguignon, Laurence; Delfour, Géraldine; Faivre, Jean-Philippe; Lacrampe-Cuyaubère, François; Tavormina, Carlotta; Todisco, Dominique; Turq, Alain; Maureille, Bruno

    2014-01-01

    The bouffia Bonneval at La Chapelle-aux-Saints is well known for the discovery of the first secure Neandertal burial in the early 20th century. However, the intentionality of the burial remains an issue of some debate. Here, we present the results of a 12-y fieldwork project, along with a taphonomic analysis of the human remains, designed to assess the funerary context of the La Chapelle-aux-Saints Neandertal. We have established the anthropogenic nature of the burial pit and underlined the taphonomic evidence of a rapid burial of the body. These multiple lines of evidence support the hypothesis of an intentional burial. Finally, the discovery of skeletal elements belonging to the original La Chapelle aux Saints 1 individual, two additional young individuals, and a second adult in the bouffia Bonneval highlights a more complex site-formation history than previously proposed. PMID:24344286

  9. Determination of brilliant green from fish pond water using carbon nanotube assisted pseudo-stir bar solid/liquid microextraction combined with UV-vis spectroscopy-diode array detection

    NASA Astrophysics Data System (ADS)

    Es'haghi, Zarrin; Khooni, Maliheh Ahmadi-Kalateh; Heidari, Tahereh

    2011-08-01

    This paper describes the development of a new design of hollow fiber solid/liquid phase microextraction (HF-SLPME) for determination of brilliant green (BG) residues in water fish ponds. This method consists of an aqueous donor phase and carbon nanotube reinforced organic solvent (acceptor phase) operated in direct immersion sampling mode. The multi-walled carbon nanotube dispersed in the organic solvent is held in the pores and lumen of a porous polypropylene hollow fiber. It is in contact directly with the aqueous donor phase. In this method the solid/liquid extractor phase is supported using a polypropylene hollow fiber membrane. Both ends of the hollow fiber segment are sealed with magnetic stoppers. This device is placed inside the donor solution and plays the rule of a pseudo-stir bar. It is disposable, so single use of the fiber reduces the risk of carry-over problems. Brilliant green (BG) after extraction from the aqueous samples with mentioned HF-SLPME device was determined by ultraviolet-visible spectroscopy with diode array detection (UV-vis/DAD). The absorption wavelength was set to 625 nm ( λmax). The effect of different variables on the extraction was evaluated and optimized to enhance the sensitivity and extraction efficiency of the proposed method. The calibration curve was linear in the range of 1.00-10,000 μg L -1 of BG in the initial solution with R2 = 0.979. Detection limit, based on three times the standard deviation of the blank, was 0.55 μg L -1. All experiments were carried out at room temperature (25 ± 0.5 °C).

  10. Genome-Wide Analysis and Characterization of Aux/IAA Family Genes in Brassica rapa

    PubMed Central

    Rameneni, Jana Jeevan; Li, Xiaonan; Sivanandhan, Ganesan; Choi, Su Ryun; Pang, Wenxing; Im, Subin; Lim, Yong Pyo

    2016-01-01

    Auxins are the key players in plant growth development involving leaf formation, phototropism, root, fruit and embryo development. Auxin/Indole-3-Acetic Acid (Aux/IAA) are early auxin response genes noted as transcriptional repressors in plant auxin signaling. However, many studies focus on Aux/ARF gene families and much less is known about the Aux/IAA gene family in Brassica rapa (B. rapa). Here we performed a comprehensive genome-wide analysis and identified 55 Aux/IAA genes in B. rapa using four conserved motifs of Aux/IAA family (PF02309). Chromosomal mapping of the B. rapa Aux/IAA (BrIAA) genes facilitated understanding cluster rearrangement of the crucifer building blocks in the genome. Phylogenetic analysis of BrIAA with Arabidopsis thaliana, Oryza sativa and Zea mays identified 51 sister pairs including 15 same species (BrIAA—BrIAA) and 36 cross species (BrIAA—AtIAA) IAA genes. Among the 55 BrIAA genes, expression of 43 and 45 genes were verified using Genebank B. rapa ESTs and in home developed microarray data from mature leaves of Chiifu and RcBr lines. Despite their huge morphological difference, tissue specific expression analysis of BrIAA genes between the parental lines Chiifu and RcBr showed that the genes followed a similar pattern of expression during leaf development and a different pattern during bud, flower and siliqua development stages. The response of the BrIAA genes to abiotic and auxin stress at different time intervals revealed their involvement in stress response. Single Nucleotide Polymorphisms between IAA genes of reference genome Chiifu and RcBr were focused and identified. Our study examines the scope of conservation and divergence of Aux/IAA genes and their structures in B. rapa. Analyzing the expression and structural variation between two parental lines will significantly contribute to functional genomics of Brassica crops and we belive our study would provide a foundation in understanding the Aux/IAA genes in B. rapa. PMID

  11. Genome-Wide Analysis and Characterization of Aux/IAA Family Genes in Brassica rapa.

    PubMed

    Paul, Parameswari; Dhandapani, Vignesh; Rameneni, Jana Jeevan; Li, Xiaonan; Sivanandhan, Ganesan; Choi, Su Ryun; Pang, Wenxing; Im, Subin; Lim, Yong Pyo

    2016-01-01

    Auxins are the key players in plant growth development involving leaf formation, phototropism, root, fruit and embryo development. Auxin/Indole-3-Acetic Acid (Aux/IAA) are early auxin response genes noted as transcriptional repressors in plant auxin signaling. However, many studies focus on Aux/ARF gene families and much less is known about the Aux/IAA gene family in Brassica rapa (B. rapa). Here we performed a comprehensive genome-wide analysis and identified 55 Aux/IAA genes in B. rapa using four conserved motifs of Aux/IAA family (PF02309). Chromosomal mapping of the B. rapa Aux/IAA (BrIAA) genes facilitated understanding cluster rearrangement of the crucifer building blocks in the genome. Phylogenetic analysis of BrIAA with Arabidopsis thaliana, Oryza sativa and Zea mays identified 51 sister pairs including 15 same species (BrIAA-BrIAA) and 36 cross species (BrIAA-AtIAA) IAA genes. Among the 55 BrIAA genes, expression of 43 and 45 genes were verified using Genebank B. rapa ESTs and in home developed microarray data from mature leaves of Chiifu and RcBr lines. Despite their huge morphological difference, tissue specific expression analysis of BrIAA genes between the parental lines Chiifu and RcBr showed that the genes followed a similar pattern of expression during leaf development and a different pattern during bud, flower and siliqua development stages. The response of the BrIAA genes to abiotic and auxin stress at different time intervals revealed their involvement in stress response. Single Nucleotide Polymorphisms between IAA genes of reference genome Chiifu and RcBr were focused and identified. Our study examines the scope of conservation and divergence of Aux/IAA genes and their structures in B. rapa. Analyzing the expression and structural variation between two parental lines will significantly contribute to functional genomics of Brassica crops and we belive our study would provide a foundation in understanding the Aux/IAA genes in B. rapa. PMID

  12. Cloning and expression analysis of novel Aux/IAA family genes in Gossypium hirsutum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Members of the auxin/indole-3-acetic acid (Aux/IAA) gene family encode proteins to mediate the responses of auxin gene expression and to regulate various aspects of plant morphological development. In this paper, we report the identification of nine cDNAs that contain complete open reading frame (OR...

  13. Oligomerization of SCFTIR1 Is Essential for Aux/IAA Degradation and Auxin Signaling in Arabidopsis.

    PubMed

    Dezfulian, Mohammad H; Jalili, Espanta; Roberto, Don Karl A; Moss, Britney L; Khoo, Kerry; Nemhauser, Jennifer L; Crosby, William L

    2016-09-01

    The phytohormone auxin is a key regulator of plant growth and development. Molecular studies in Arabidopsis have shown that auxin perception and signaling is mediated via TIR1/AFB-Aux/IAA co-receptors that assemble as part of the SCFTIR1/AFB E3 ubiquitin-ligase complex and direct the auxin-regulated degradation of Aux/IAA transcriptional repressors. Despite the importance of auxin signaling, little is known about the functional regulation of the TIR1/AFB receptor family. Here we show that TIR1 can oligomerize in planta via a set of spatially clustered amino acid residues. While none of the residues identified reside in the interaction interface of the TIR1-Aux/IAA degron, they nonetheless regulate the binding of TIR1 to Aux/IAA substrate proteins and their subsequent degradation in vivo as an essential aspect of auxin signaling. We propose oligomerization of TIR1 as a novel regulatory mechanism in the regulation of auxin-mediated plant patterning and development. PMID:27618443

  14. The Acquisition of Aux. Papers and Reports on Child Language Development, No. 8.

    ERIC Educational Resources Information Center

    Kypriotaki, Lyn

    This report examines the question of whether grammatical rules are globally learned and applied. It also attempts to determine the underlying word order in English as well as the developmental sequence of the acquisition of Aux. A sentence-repetition test using positive statements, positive questions, and negative questions was administered to 30…

  15. Comportement de frittés et de films d'oxyde de titane en présence d'atmosphères gazeuses, hors équilibre thermodynamique, en régime stationnaire; application aux capteurs résistifs d'oxygène

    NASA Astrophysics Data System (ADS)

    Jerisian, R.; Gautron, J.; Loup, J. P.

    1992-04-01

    mesurée, en régime stationnaire, en fonction du débit des gaz ; ces atmosphères sont d'autant plus éloignées de l'équilibre que le débit est élevé. On montre que les variations de résistance des échantillons, en fonction du débit, dépendent du domaine de pression partielle d'oxygène, de la température et de la structure des échantillons. La sensibilité à l'oxygène est accrue par un morphologie qui, à l'échelle macroscopique, favorise la diffusion de l'oxygène et qui, à l'échelle microscopique, permet la création de barrière de potentiel aux joints de grains. En milieu oxydant, à 870 K, un mécanisme de volume qui met en jeu la cinétique des échanges avec la phase gazeuse, détermine une variation de résistance en P_{O_2}^{1/4}/P_{CO}^{1/2}. En milieu réducteur, à la même température, la non-stœchiométrie en volume de l'oxyde est fixée par le couple redox CO/CO2 comme si l'atmosphère était en équilibre thermodynamique. Mais l'abondance des électrons de conduction, favorise la chimisorption de l'oxygène qui contrôle la résistance des couches selon une loi en P_{O_2}^{1/2} en créant des barrières de potentiel à la surface des grains. Des modèles, permettant le calcul du potentiel de surface ainsi que du taux de recouvrement, sont développés ; la comparaison des modèles indique une diffusion relativement lente des lacunes d'oxygène à 870 K. A 1 100 K, l'atmosphère tend à être à l'équilibre thermodynamique : i) en atmosphère oxydante, tous les capteurs sont en équilibre avec la pression partielle d'oxygène ; ii) en atmosphère réductrice, dominée par le couple redox CO/CO2, seules les couches sont sensibles à la présence de traces d'oxygène.

  16. Triboelectric Charging at the Nanostructured Solid/Liquid Interface for Area-Scalable Wave Energy Conversion and Its Use in Corrosion Protection.

    PubMed

    Zhao, Xue Jiao; Zhu, Guang; Fan, You Jun; Li, Hua Yang; Wang, Zhong Lin

    2015-07-28

    We report a flexible and area-scalable energy-harvesting technique for converting kinetic wave energy. Triboelectrification as a result of direct interaction between a dynamic wave and a large-area nanostructured solid surface produces an induced current among an array of electrodes. An integration method ensures that the induced current between any pair of electrodes can be constructively added up, which enables significant enhancement in output power and realizes area-scalable integration of electrode arrays. Internal and external factors that affect the electric output are comprehensively discussed. The produced electricity not only drives small electronics but also achieves effective impressed current cathodic protection. This type of thin-film-based device is a potentially practical solution of on-site sustained power supply at either coastal or off-shore sites wherever a dynamic wave is available. Potential applications include corrosion protection, pollution degradation, water desalination, and wireless sensing for marine surveillance. PMID:26154990

  17. [PMIM]Br@TiO2 nanocomposite reinforced hollow fiber solid/liquid phase microextraction: an effective extraction technique for measurement of benzodiazepines in hair, urine and wastewater samples combined with high-performance liquid chromatography.

    PubMed

    Es'haghi, Zarrin; Nezhadali, Azizollah; Bahar, Shahriyar; Bohlooli, Shahab; Banaei, Alireza

    2015-02-01

    A new design of hollow fiber solid-liquid phase microextraction (HF-SLPME) was developed for the determination of benzodiazepines (BZPs) in hair, urine and wastewater. The membrane extraction with 1-pentyl-3-methylimidazolium bromide coated titanium dioxide ([PMIM]Br@TiO2) sorbent used in this research is a two-phase supported membrane extraction consisting of an aqueous (donor phase), and n-octanol/nano [PMIM]Br@TiO2 (acceptor phase) system operated in direct immersion sampling mode. The 1-pentyl-3-methylimidazolium bromide (ionic liquid) coated nano TiO2 dispersed in the organic solvent (n-octanol) is held into a porous membrane supported by capillary forces and sonification. It is in contact with the feed phase, which is the aqueous sample. The experimental setup is very simple and highly affordable. The hollow fiber is disposable, so single use of the fiber reduces the risk of cross-contamination and carry-over problems. The proposed method allows the very effective and enriched recuperation of BZPs into one single extract. In order to obtain high extraction efficiency of the analytes using this novel sorbent, the main parameters were optimized. Under the optimized extraction conditions, the method showed good linearity (0.05-6000ngmL(-1)), low limits of detection (0.08-0.5ngmL(-1)) and good enrichment (533-1190). PMID:25589255

  18. Ultrasound/microwave-assisted solid-liquid-solid dispersive extraction with high-performance liquid chromatography coupled to tandem mass spectrometry for the determination of neonicotinoid insecticides in Dendrobium officinale.

    PubMed

    Zheng, Shuilian; Wu, Huizhen; Li, Zuguang; Wang, Jianmei; Zhang, Hu; Qian, Mingrong

    2015-01-01

    A one-step ultrasound/microwave-assisted solid-liquid-solid dispersive extraction procedure was used for the simultaneous determination of eight neonicotinoids (dinotefuran, nitenpyram, thiamethoxam, clothianidin, imidacloprid, acetamiprid, thiacloprid, imidaclothiz) in dried Dendrobium officinale by liquid chromatography combined with electrospray ionization triple quadrupole tandem mass spectrometry in multiple reaction monitoring mode. The samples were quickly extracted by acetonitrile and cleaned up by the mixed dispersing sorbents including primary secondary amine, C18 , and carbon-GCB. Parameters that could influence the ultrasound/microwave-assisted extraction efficiency such as microwave irradiation power, ultrasound irradiation power, temperature, and solvent were investigated. Recovery studies were performing well (70.4-113.7%) at three examined spiking levels (10, 50, and 100 μg/kg). Meanwhile, the limits of quantification for the neonicotinoids ranged from 0.87 to 1.92 μg/kg. The method showed good linearity in the concentration range of 1-100 μg/L with correlation coefficients >0.99. This quick and useful analytical method could provide a basis for monitoring neonicotinoid insecticide residues in herbs. PMID:25348589

  19. Determination of perfluorinated alkyl acids in corn, popcorn and popcorn bags before and after cooking by focused ultrasound solid-liquid extraction, liquid chromatography and quadrupole-time of flight mass spectrometry.

    PubMed

    Moreta, Cristina; Tena, María Teresa

    2014-08-15

    An analytical method is proposed to determine ten perfluorinated alkyl acids (PFAAs) [nine perfluorocarboxylic acids (PFCAs) and perfluorooctane sulfonate (PFOS)] in corn, popcorn and microwave popcorn packaging by focused ultrasound solid-liquid extraction (FUSLE) and ultra high performance liquid chromatography (UHPLC) coupled to quadrupole-time of flight mass spectrometry (QTOF-MS/MS). Selected PFAAs were extracted efficiently in only one 10-s cycle by FUSLE, a simple, safe and inexpensive technique. The developed method was validated for microwave popcorn bags matrix as well as corn and popcorn matrices in terms of linearity, matrix effect error, detection and quantification limits, repeatability and recovery values. The method showed good accuracy with recovery values around 100% except for the lowest chain length PFAAs, satisfactory reproducibility with RSDs under 16%, and sensitivity with limits of detection in the order of hundreds picograms per gram of sample (between 0.2 and 0.7ng/g). This method was also applied to the analysis of six microwave popcorn bags and the popcorn inside before and after cooking. PFCAs contents between 3.50ng/g and 750ng/g were found in bags, being PFHxA (perfluorohexanoic acid) the most abundant of them. However, no PFAAs were detected either corn or popcorn, therefore no migration was assumed. PMID:24986069

  20. Micro-focused ultrasonic solid-liquid extraction (muFUSLE) combined with HPLC and fluorescence detection for PAHs determination in sediments: optimization and linking with the analytical minimalism concept.

    PubMed

    Capelo, J L; Galesio, M M; Felisberto, G M; Vaz, C; Pessoa, J Costa

    2005-06-15

    Analytical minimalism is a concept that deals with the optimization of all stages of an analytical procedure so that it becomes less time, cost, sample, reagent and energy consuming. The guide-lines provided in the USEPA extraction method 3550B recommend the use of focused ultrasound (FU), i.e., probe sonication, for the solid-liquid extraction of Polycyclic Aromatic Hydrocarbons, PAHs, but ignore the principle of analytical minimalism. The problems related with the dead sonication zones, often present when high volumes are sonicated with probe, are also not addressed. In this work, we demonstrate that successful extraction and quantification of PAHs from sediments can be done with low sample mass (0.125g), low reagent volume (4ml), short sonication time (3min) and low sonication amplitude (40%). Two variables are here particularly taken into account for total extraction: (i) the design of the extraction vessel and (ii) the solvent used to carry out the extraction. Results showed PAHs recoveries (EPA priority list) ranged between 77 and 101%, accounting for more than 95% for most of the PAHs here studied, as compared with the values obtained after soxhlet extraction. Taking into account the results reported in this work we recommend a revision of the EPA guidelines for PAHs extraction from solid matrices with focused ultrasound, so that these match the analytical minimalism concept. PMID:18970118

  1. A Mn-54 Radiotracer Study of Mn Isotope Solid-Liquid Exchange during Reductive Transformation of Vernadite (δ-MnO₂) by Aqueous Mn(II)

    SciTech Connect

    Elzinga, Evert J.; Kustka, Adam B.

    2015-04-09

    We employed Mn-54 radiotracers to characterize the extent and dynamics of Mn atom exchange between aqueous Mn(II) and vernadite (δ-Mn(IV)O2) at pH 7.5 under anoxic conditions. Exchange of Mn atoms between the solid and liquid phase is rapid, reaching dynamic equilibrium in 2–4 days. We propose that during the initial stages of reaction, Mn atom exchange occurs through consecutive comproportionation-disproportionation reactions where interfacial electron transfer from adsorbed Mn(II) to lattice Mn(IV) generates labile Mn(III) cations that rapidly disproportionate to reform aqueous Mn(II) and solid-phase Mn(IV). Following nucleation of Mn(III)OOH phases, additional exchange likely occurs through electron transfer from aqueous Mn(II) to solid-phase Mn(III). Our results provide evidence for the fast and extensive production of transient Mn(III) species at the vernadite surface upon contact of this substrate with dissolved Mn(II). We further show that HEPES buffer is a reductant of lattice Mn(IV) in the vernadite structure in our experiments. The methods and results presented here introduce application of Mn-54 tracers as a facile tool to further investigate the formation kinetics of labile Mn(III) surface species and their impacts on Mn-oxide structure and reactivity over a range of environmentally relevant geochemical conditions.

  2. Solid-liquid transfer of biophenols from olive leaves for the enrichment of edible oils by a dynamic ultrasound-assisted approach.

    PubMed

    Japón-Luján, Rafael; Janeiro, Patricia; Luque de Castro, María Dolores

    2008-08-27

    A continuous approach assisted by ultrasound for direct enrichment of edible oils (olive, sunflower, and soya) with the main phenols in olive leaves (i.e., oleuropein, verbascoside, apigenin-7-glucoside, and luteolin-7-glucoside) has been developed. Multivariate methodology was used to carry out a detailed optimization of the enrichment, and quantitation of the transferred compounds was based on LC-MS-MS in multiple reaction monitoring optimizing the most sensitive transition for each biophenol. Under the optimal working conditions, only 20 min is necessary to enrich the edible oils with 14.45-9.92 microg/mL oleuropein, 2.29-2.12 microg/mL verbascoside, 1.91-1.51 microg/mL apigenin-7-glucoside, and 1.60-1.42 microg/mL luteolin-7-glucoside. The enrichment method is carried out at room temperature and is organic-solvent-free; thus, the healthy properties of the edible oils improve as does their quality. Also, the low acquisition and maintenance costs of an ultrasound source and its application in a dynamic system make advisable the industrial implementation of the proposed method. PMID:18656923

  3. Genome-wide analysis of Aux/IAA and ARF gene families in Populus trichocarpa

    SciTech Connect

    Kalluri, Udaya C; DiFazio, Stephen P; Brunner, A.; Tuskan, Gerald A

    2007-01-01

    Auxin/Indole-3-Acetic Acid (Aux/IAA) and Auxin Response Factor (ARF) transcription factors are key regulators of auxin responses in plants. A total of 35 Aux/IAA and 39 ARF genes were identified in the Populus genome. Comparative phylogenetic analysis revealed that the subgroups PoptrARF2, 6, 9 and 16 and PoptrIAA3, 16, 27 and 29 have differentially expanded in Populus relative to Arabidopsis. Activator ARFs were found to be two fold-overrepresented in the Populus genome. PoptrIAA and PoptrARF gene families appear to have expanded due to high segmental and low tandem duplication events. Furthermore, expression studies showed that genes in the expanded PoptrIAA3 subgroup display differential expression. The gene-family analysis reported here will be useful in conducting future functional genomics studies to understand how the molecular roles of these large gene families translate into a diversity of biologically meaningful auxin effects.

  4. The Aux/IAA, Sl-IAA17 regulates quality parameters over tomato fruit development

    PubMed Central

    Su, LY; Audran, C; Bouzayen, M; Roustan, JP; Chervin, C

    2015-01-01

    Auxin is known to be involved in all the stages of fruit development. Aux/IAAs are regulators of the auxin signaling at the transcription level. In a recent study, using RNAi strategy to limit the expression Sl-IAA17, it was shown that this tomato AuxIAA regulates fruit size mainly through altering the ploidy level of pericarp cells. Indeed, Sl-IAA17 down-regulated lines showed fruit with larger diameter, bigger volume and heavier weight than wild-type. The increase in fruit size was associated with thicker pericarp rather than larger locular spaces. The thicker pericarp was linked to larger cells harboring higher ploidy level, probably due to more active endoreduplication at the beginning of fruit development. The present report describes some additional phenotypes, not described in the initial article, among which are soluble solid content, juice pH, firmness, seed weight and fruit morphology. PMID:26317283

  5. Genome-wide survey and comprehensive expression profiling of Aux/IAA gene family in chickpea and soybean

    PubMed Central

    Singh, Vikash K.; Jain, Mukesh

    2015-01-01

    Auxin plays a central role in many aspects of plant growth and development. Auxin/Indole-3-Acetic Acid (Aux/IAA) genes cooperate with several other components in the perception and signaling of plant hormone auxin. An investigation of chickpea and soybean genomes revealed 22 and 63 putative Aux/IAA genes, respectively. These genes were classified into six subfamilies on the basis of phylogenetic analysis. Among 63 soybean Aux/IAA genes, 57 (90.5%) were found to be duplicated via whole genome duplication (WGD)/segmental events. Transposed duplication played a significant role in tandem arrangements between the members of different subfamilies. Analysis of Ka/Ks ratio of duplicated Aux/IAA genes revealed purifying selection pressure with restricted functional divergence. Promoter sequence analysis revealed several cis-regulatory elements related to auxin, abscisic acid, desiccation, salt, seed, and endosperm, indicating their role in development and stress responses. Expression analysis of chickpea and soybean Aux/IAA genes in various tissues and stages of development demonstrated tissue/stage specific differential expression. In soybean, at least 16 paralog pairs, duplicated via WGD/segmental events, showed almost indistinguishable expression pattern, but eight pairs exhibited significantly diverse expression patterns. Under abiotic stress conditions, such as desiccation, salinity and/or cold, many Aux/IAA genes of chickpea and soybean revealed differential expression. qRT-PCR analysis confirmed the differential expression patterns of selected Aux/IAA genes in chickpea. The analyses presented here provide insights on putative roles of chickpea and soybean Aux/IAA genes and will facilitate elucidation of their precise functions during development and abiotic stress responses. PMID:26579165

  6. Decommissioning of the nuclear licensed facilities at the Fontenay aux Roses CEA center

    SciTech Connect

    Jeanjacques, Michel; Piketty, Laurence; Letuhaire, Nathalie; Mandard, Lionel; Meden, Igor; Estivie, David; Boissonneau, Jean Francois; Fouquereau, Alain; Pichereau, Eric; Binet, Cedric

    2007-07-01

    Available in abstract form only. Full text of publication follows: The French Atomic Energy Commission (CEA) center at Fontenay aux Roses (CEN-FAR) is the Commission's oldest center is located in the southern suburbs of Paris. It was opened on 26 March 1946 to host the first French nuclear reactor ZOE that went critical on 12 December 1946. The first laboratories were installed in existing buildings on the site. (authors)

  7. The influence of solid/liquid separation techniques on the sugar yield in two-step dilute acid hydrolysis of softwood followed by enzymatic hydrolysis

    PubMed Central

    Monavari, Sanam; Galbe, Mats; Zacchi, Guido

    2009-01-01

    Background Two-step dilute acid hydrolysis of softwood, either as a stand-alone process or as pretreatment before enzymatic hydrolysis, is considered to result in higher sugar yields than one-step acid hydrolysis. However, this requires removal of the liquid between the two steps. In an industrial process, filtration and washing of the material between the two steps is difficult, as it should be performed at high pressure to reduce energy demand. Moreover, the application of pressure leads to more compact solids, which may affect subsequent processing steps. This study was carried out to investigate the influence of pressing the biomass, in combination with the effects of not washing the material, on the sugar yield obtained from two-step dilute acid hydrolysis, with and without subsequent enzymatic digestion of the solids. Results Washing the material between the two acid hydrolysis steps, followed by enzymatic digestion, resulted in recovery of 96% of the mannose and 81% of the glucose (% of the theoretical) in the liquid fraction, regardless of the choice of dewatering method (pressing or vacuum filtration). Not washing the solids between the two acid hydrolysis steps led to elevated acidity of the remaining solids during the second hydrolysis step, which resulted in lower yields of mannose, 85% and 74% of the theoretical, for the pressed and vacuum-filtered slurry, respectively, due to sugar degradation. However, this increase in acidity resulted in a higher glucose yield (94.2%) from pressed slurry than from filtered slurry (77.6%). Conclusion Pressing the washed material between the two acid hydrolysis steps had no significant negative effect on the sugar yields of the second acid hydrolysis step or on enzymatic hydrolysis. Not washing the material resulted in a harsher second acid hydrolysis step, which caused greater degradation of the sugars during subsequent acid hydrolysis of the solids, particularly in case of the vacuum-filtered solids. However

  8. Aux Vases Sandstone diagenesis: Implications for hydrocarbon recovery from southern Illinois reservoirs

    SciTech Connect

    Seyler, B.D.; Beaty, D.S.; Huff, B.G. )

    1991-03-01

    The Aux Vases Sandstone (Mississippian) is a problematic yet productive reservoir in the Illinois basin. The Aux Vases Formation was deposited in a mixed siliciclastic-carbonate offshore environment. Hydrocarbon reservoirs are dominantly elongate sandstone bodies interpreted as subtidal facies within a prograding tidally influenced deposystem. Oil saturated zones, in most cases, are composed of fine-grained, cross-bedded, friable, feldspathic quartz sandstone. Resistivity logs, even from productive wells, are typically characterized by unusually low resistivities (2-4 ohms) that lead to high calculated water saturations. X-ray diffraction, SEM/EDS, and thin section studies were used to analyze diagenetic processes that may affect hydrocarbon production in several Aux Vases reservoirs. Diagenetic processes common to the field studied include: (1) early calcite cementation occluding primary porosity and inhibiting compaction, (2) dissolution of feldspar grains to form authigenic clay, (3) dissolution of early calcite cement, (4) diagenesis of detrital clay minerals into new authigenic clay minerals, and (5) multiple stages of quartz overgrowths that reduce porosity. Commonly used drilling and completion practices may adversely affect reservoir quality by reacting with diagenetic products. Loosening of the fine mineral fraction that causes migration of fines and swelling of expandable clay minerals are examples of this type of damage. Knowledge of reservoir mineralogy and diagenesis may influence drilling and completion practices and affect selection of secondary and tertiary recovery methods.

  9. In Situ Adsorption Studies at the Solid/Liquid Interface:Characterization of Biological Surfaces and Interfaces Using SumFrequency Generation Vibrational Spectroscopy, Atomic Force Microscopy,and Quartz Crystal Microbalance

    SciTech Connect

    Phillips, D.C.

    2006-05-16

    Sum frequency generation (SFG) vibrational spectroscopy, atomic force microscopy (AFM), and quartz crystal microbalance (QCM) have been used to study the molecular surface structure, surface topography and mechanical properties, and quantitative adsorbed amount of biological molecules at the solid-liquid interface. The molecular-level behavior of designed peptides adsorbed on hydrophobic polystyrene and hydrophilic silica substrates has been examined as a model of protein adsorption on polymeric biomaterial surfaces. Proteins are such large and complex molecules that it is difficult to identify the features in their structure that lead to adsorption and interaction with solid surfaces. Designed peptides which possess secondary structure provide simple model systems for understanding protein adsorption. Depending on the amino acid sequence of a peptide, different secondary structures ({alpha}-helix and {beta}-sheet) can be induced at apolar (air/liquid or air/solid) interfaces. Having a well-defined secondary structure allows experiments to be carried out under controlled conditions, where it is possible to investigate the affects of peptide amino acid sequence and chain length, concentration, buffering effects, etc. on adsorbed peptide structure. The experiments presented in this dissertation demonstrate that SFG vibrational spectroscopy can be used to directly probe the interaction of adsorbing biomolecules with a surface or interface. The use of well designed model systems aided in isolation of the SFG signal of the adsorbing species, and showed that surface functional groups of the substrate are sensitive to surface adsorbates. The complementary techniques of AFM and QCM allowed for deconvolution of the effects of surface topography and coverage from the observed SFG spectra. Initial studies of biologically relevant surfaces are also presented: SFG spectroscopy was used to study the surface composition of common soil bacteria for use in bioremediation of nuclear

  10. Ultra-low temperature (≤300 °C) growth of Ge-rich SiGe by solid-liquid-coexisting annealing of a-GeSn/c-Si structures

    NASA Astrophysics Data System (ADS)

    Sadoh, Taizoh; Chikita, Hironori; Matsumura, Ryo; Miyao, Masanobu

    2015-09-01

    Ultra-low temperature (≤300 °C) growth of Ge-rich SiGe on Si substrates is strongly desired to realize advanced electronic and optical devices, which can be merged onto Si large-scale integrated circuits (LSI). To achieve this, annealing characteristics of a-GeSn/c-Si structures are investigated under wide ranges of the initial Sn concentrations (0%-26%) and annealing conditions (300-1000 °C, 1 s-48 h). Epitaxial growth triggered by SiGe mixing is observed after annealing, where the annealing temperatures necessary for epitaxial growth significantly decrease with increasing initial Sn concentration and/or annealing time. As a result, Ge-rich (˜80%) SiGe layers with Sn concentrations of ˜2% are realized by ultra-low temperature annealing (300 °C, 48 h) for a sample with the initial Sn concentration of 26%. The annealing temperature (300 °C) is in the solid-liquid coexisting temperature region of the phase diagram for Ge-Sn system. From detailed analysis of crystallization characteristics and composition profiles in grown layers, it is suggested that SiGe mixing is generated by a liquid-phase reaction even at ultra-low temperatures far below the melting temperature of a-GeSn. This ultra-low-temperature growth technique of Ge-rich SiGe on Si substrates is expected to be useful to realize next-generation LSI, where various multi-functional devices are integrated on Si substrates.

  11. Ultra-low temperature (≤300 °C) growth of Ge-rich SiGe by solid-liquid-coexisting annealing of a-GeSn/c-Si structures

    SciTech Connect

    Sadoh, Taizoh Chikita, Hironori; Miyao, Masanobu; Matsumura, Ryo

    2015-09-07

    Ultra-low temperature (≤300 °C) growth of Ge-rich SiGe on Si substrates is strongly desired to realize advanced electronic and optical devices, which can be merged onto Si large-scale integrated circuits (LSI). To achieve this, annealing characteristics of a-GeSn/c-Si structures are investigated under wide ranges of the initial Sn concentrations (0%–26%) and annealing conditions (300–1000 °C, 1 s–48 h). Epitaxial growth triggered by SiGe mixing is observed after annealing, where the annealing temperatures necessary for epitaxial growth significantly decrease with increasing initial Sn concentration and/or annealing time. As a result, Ge-rich (∼80%) SiGe layers with Sn concentrations of ∼2% are realized by ultra-low temperature annealing (300 °C, 48 h) for a sample with the initial Sn concentration of 26%. The annealing temperature (300 °C) is in the solid-liquid coexisting temperature region of the phase diagram for Ge-Sn system. From detailed analysis of crystallization characteristics and composition profiles in grown layers, it is suggested that SiGe mixing is generated by a liquid-phase reaction even at ultra-low temperatures far below the melting temperature of a-GeSn. This ultra-low-temperature growth technique of Ge-rich SiGe on Si substrates is expected to be useful to realize next-generation LSI, where various multi-functional devices are integrated on Si substrates.

  12. Determination of bisphenol-type endocrine disrupting compounds in food-contact recycled-paper materials by focused ultrasonic solid-liquid extraction and ultra performance liquid chromatography-high resolution mass spectrometry.

    PubMed

    Pérez-Palacios, David; Fernández-Recio, Miguel Ángel; Moreta, Cristina; Tena, María Teresa

    2012-09-15

    Focused ultrasonic solid-liquid extraction (FUSLE) and reverse-phase ultra performance liquid chromatography (UPLC) coupled to a quadrupole-time of flight mass spectrometer (Q-TOF-MS) was applied to the determination of bisphenol-type endocrine disrupting compounds (EDCs) in food-contact recycled-paper materials. Recycled paper is a potential source of EDCs. Bisphenol A (BPA), bisphenol F (BPF) and their derivatives bisphenol A diglycidyl ether (BADGE) and bisphenol F diglycidyl ether (BFDGE) are used for the production of epoxy resins employed in the formulation of printing inks. The FUSLE of bisphenol-type EDCs from packaging is reported for the first time. First, different extraction solvents were studied and methanol was selected. Then, the main FUSLE factors affecting the extraction efficiency (solvent volume, extraction time and ultrasonic irradiation power) were studied by means of a central composite design. The FUSLE conditions selected for further experiments were 20 ml of methanol at ultrasonic amplitude of 100% for 5s. Finally, the number of extraction cycles necessary for complete extraction was established in two. The analysis of the FUSLE extracts was carried out by UPLC-Q-TOF-MS with electrospray ionization and the determination of the four analytes took place in only 4 min. The FUSLE and UPLC-ESI-QTOF-MS method was validated and applied to the analysis of different food-contact recycled-paper-based materials and packaging. The proposed method provided recoveries from 72% to 97%, repeatability and intermediate precision under 9% and 14%, respectively, and detection limits of 0.33, 0.16, 0.65 and 0.40 μg/g for BPA, BPF, BADGE and BFDGE, respectively. The analysis of paper and cardboard samples confirmed the presence of EDCs in these packaging. PMID:22967537

  13. The ARF, AUX/IAA and GH3 gene families in citrus: genome-wide identification and expression analysis during fruitlet drop from abscission zone A.

    PubMed

    Xie, Rangjin; Pang, Shaoping; Ma, Yanyan; Deng, Lie; He, Shaolan; Yi, Shilai; Lv, Qiang; Zheng, Yongqiang

    2015-12-01

    Completion of the whole genome sequencing of citrus enabled us to perform genome-wide identification and functional analysis of the gene families involved in agronomic traits and morphological diversity of citrus. In this study, 22 CitARF, 11 CitGH3 and 26 CitAUX/IAA genes were identified in citrus, respectively. Phylogenetic analysis revealed that all the genes of each gene family could be subdivided into three groups and showed strong evolutionary conservation. The GH3 and AUX/IAA gene families shrank and ARF gene family was highly conserved in the citrus genome after speciation from Arabidopsis thaliana. Tissue-specific expression profiles revealed that 54 genes were expressed in at least one tissue while just 5 genes including CitARF07, CitARF20, CitGH3.04, CitAUX/IAA25 and CitAUX/IAA26 with very low expression level in all tissues tested, suggesting that the CitARF, CitGH3 and CitAUX/IAA gene families played important roles in the development of citrus organs. In addition, our data found that the expression of 2 CitARF, 4 CitGH3 and 4 AUX/IAA genes was affected by IAA treatment, and 7 genes including, CitGH3.04, CitGH3.07, CitAUX/IAA03, CitAUX/IAA04, CitAUX/IAA18, CitAUX/IAA19 and CitAUX/IAA23 were related to fruitlet abscission. This study provides a foundation for future studies on elucidating the precise role of citrus ARF, GH3 and AUX/IAA genes in early steps of auxin signal transduction and open up a new opportunity to uncover the molecular mechanism underlying citrus fruitlet abscission. PMID:25982744

  14. Complementation of Agrobacterium tumefaciens tumor-inducing aux mutants by genes from the TR-region of the Ri plasmid of Agrobacterium rhizogenes

    PubMed Central

    Offringa, I. A.; Melchers, L. S.; Regensburg-Tuink, A. J. G.; Costantino, P.; Schilperoort, R. A.; Hooykaas, P. J. J.

    1986-01-01

    In this paper we provide information indicating that the agropine-type root-inducing (Ri) plasmid pRi1855 of Agrobacterium rhizogenes contains functional genes for auxin production (aux) in the right transferred DNA (T-DNA) region (TR-region). These genes were cloned and introduced into the T-region of the tumor-inducing (Ti) plasmids of mutants of Agrobacterium tumefaciens carrying an aux mutation. Depending on the Ri aux gene present, the oncogenicity of the Ti aux-1 and/or aux-2 mutations was restored, showing that the Ri aux genes are able to complement the Ti aux genes. Agrobacterium strains with an agropine-type Ri plasmid not only cause hairy root on certain plant species, but they also induce tumors on other plant species. In this paper it is shown that a mutation in either of the aux genes in the Ri plasmid leads to a total loss of tumorigenicity and a strongly diminished rhizogenicity of the host bacterium, revealing that the aux genes are important for tumor and root induction. Agrobacterium strains containing the TR-region but not the TL (left)-region of the Ri plasmid are still tumorigenic on certain plant species but are no longer capable of hairy-root induction. Images PMID:16593762

  15. Loi constitutive chimioplastique pour le beton expose aux hautes temperatures

    NASA Astrophysics Data System (ADS)

    Hammoud, Rabah

    degradation of exothermic origin. This experimental program puts emphasis on the fragile nature of the preheated concrete and demonstrates the non-applicability of two failure criteria often used in engineering calculation. An alternative is proposed and well-tested. Indeed, exposing the concrete to high temperature results in irreversible loss of stiffness as well as a loss of decohesion strength. These losses are, typically, expressed through semi-empirical relationships of the mechanical properties with temperature. Unfortunately, these relationships are inadequate because the direct impact of this degradation, on the macroscopic scale, can result in a dependency relationship between the elastic properties and the hydrates mass. Therefore, unlike traditional methods using conventional elasto-plastic models and adjusting certain parameters with local temperature, the proposed constitutive law that incorporates a function of dehydration similar to the softening index in chemo-plastics gives good results. An Etse and Willam similar criterion is used and modified for the occasion. Hardening and softening mechanisms are then needed to expand and contract the loading surface for defining the strength of the concrete on a wide range of dehydration processes. The direction and magnitude of a permanent deformation, core of the inelastic domain, are defined through the development of non-associated chemoplastic potential and new curve of ductility. The influence of hydrostatic pressure (dilatancy) and dehydration on the concrete behavior are taken into account in our model. The model is implemented in the Matlab(c) code. Strains and stresses generated in the concrete are now accurately predicted. To illustrate the capabilities of the developed model to predict the complex behavior of concrete exposed to high temperature, simulations are performed through numerical loading paths scenarios. The model is able to accurately reproduce all the experimental data.

  16. Chemical composition and geologic history of saline waters in Aux Vases and Cypress Formations, Illinois Basin

    USGS Publications Warehouse

    Demir, I.; Seyler, B.

    1999-01-01

    Seventy-six samples of formation waters were collected from oil wells producing from the Aux Vases or Cypress Formations in the Illinois Basin. Forty core samples of the reservoir rocks were also collected from the two formations. Analyses of the samples indicated that the total dissolved solids content (TDS) of the waters ranged from 43,300 to 151,400 mg/L, far exceeding the 35,400 mg/mL of TDS found in typical seawater. Cl-Br relations suggested that high salinities in the Aux Vases and Cypress formation waters resulted from the evaporation of original seawater and subsequent mixing of the evaporated seawater with concentrated halite solutions. Mixing with the halite solutions increased Na and Cl concentrations and diluted the concentration of other ions in the formation waters. The elemental concentrations were influenced further by diagenetic reactions with silicate and carbonate minerals. Diagenetic signatures revealed by fluid chemistry and rock mineralogy delineated the water-rock interactions that took place in the Aux Vases and Cypress sandstones. Dissolution of K-feldspar released K into the solution, leading to the formation of authigenic illite and mixed-layered illite/smectite. Some Mg was removed from the solution by the formation of authigenic chlorite and dolomite. Dolomitization, calcite recrystallization, and contribution from clay minerals raised Sr levels significantly in the formation waters. The trend of increasing TDS of the saline formation waters with depth can be explained with density stratification. But, it is difficult to explain the combination of the increasing TDS and increasing Ca/Na ratio with depth without invoking the controversial 'ion filtration' mechanism.

  17. Simultaneous determination of a variety of endocrine disrupting compounds in carrot, lettuce and amended soil by means of focused ultrasonic solid-liquid extraction and dispersive solid-phase extraction as simplified clean-up strategy.

    PubMed

    Mijangos, L; Bizkarguenaga, E; Prieto, A; Fernández, L A; Zuloaga, O

    2015-04-10

    The present study is focused on the development of an analytical method based on focused ultrasonic solid-liquid extraction (FUSLE) followed by dispersive solid-phase extraction (dSPE) clean-up and liquid chromatography-triple quadrupole tandem mass spectrometry (LC-MS/MS) optimised for the simultaneous analysis of certain endocrine disrupting compounds (EDCs), including alkylphenols (APs), bisphenol A (BPA), triclosan (TCS) and several hormones and sterols in vegetables (lettuce and carrot) and amended soil samples. Different variables affecting the chromatographic separation, the electrospray ionisation and mass spectrometric detection were optimised in order to improve the sensitivity of the separation and detection steps. Under the optimised extraction conditions (sonication of 5min at 33% of power with pulse times on of 0.8s and pulse times off of 0.2s in 10mL of n-hexane:acetone (30:70, v:v) mixture using an ice bath), different dSPE clean-up sorbents, such as Florisil, Envi-Carb, primary-secondary amine bonded silica (PSA) and C18, or combinations of them were evaluated for FUSLE extracts before LC-MS/MS. Apparent recoveries and precision in terms of relative standard deviation (RSDs %) of the method were determined at two different fortification levels (according to the matrix and the analyte) and values in the 70-130% and 2-27% ranges, respectively, were obtained for most of the target analytes and matrices. Matrix-matched calibration approach and the use of labelled standards as surrogates were needed for the properly quantification of most analytes and matrices. Method detection limits (MDLs), estimated with fortified samples, in the ranges of 0.1-100ng/g for carrot, 0.2-152ng/g for lettuce and 0.9-31ng/g for amended soil were obtained. The developed methodology was applied to the analysis of 11 EDCs in both real vegetable bought in a local market and in compost (from a local wastewater treatment plant, WWTP) amended soil samples. PMID:25746759

  18. Groupes quantiques associes aux courbes rationnelles et elliptiques et leurs applications

    NASA Astrophysics Data System (ADS)

    Silantyev, A.

    2009-01-01

    The thesis was defended by the author in University of Angers (France). It consists of four parts. The fist part (in French) is introductory and is devoted to relation between quantum groups, integrable systems and statistical models. In the second part (in English) the transition function of the periodic Toda chain is interpreted in terms of the formalism of rational Lax operators. In the third part (in French) one compares two elliptic quantum groups and one conclude that they belong to two different bialgebra categories. The fourth part (in English) contains a construction of the partition function of the SOS model in terms of the projections of an elliptic quantum group.

  19. Diversity of Stability, Localization, Interaction and Control of Downstream Gene Activity in the Maize Aux/IAA Protein Family

    PubMed Central

    Ludwig, Yvonne; Berendzen, Kenneth W.; Xu, Changzheng; Piepho, Hans-Peter; Hochholdinger, Frank

    2014-01-01

    AUXIN/INDOLE-3-ACETIC ACID (Aux/IAA) proteins are central regulators of auxin signal transduction. They control many aspects of plant development, share a conserved domain structure and are localized in the nucleus. In the present study, five maize Aux/IAA proteins (ZmIAA2, ZmIAA11, ZmIAA15, ZmIAA20 and ZmIAA33) representing the evolutionary, phylogenetic and expression diversity of this gene family were characterized. Subcellular localization studies revealed that ZmIAA2, ZmIAA11 and ZmIAA15 are confined to the nucleus while ZmIAA20 and ZmIAA33 are localized in both the nucleus and the cytoplasm. Introduction of specific point mutations in the degron sequence (VGWPPV) of domain II by substituting the first proline by serine or the second proline by leucine stabilized the Aux/IAA proteins. While protein half-life times between ∼11 min (ZmIAA2) to ∼120 min (ZmIAA15) were observed in wild-type proteins, the mutated forms of all five proteins were almost as stable as GFP control proteins. Moreover, all five maize Aux/IAA proteins repressed downstream gene expression in luciferase assays to different degrees. In addition, bimolecular fluorescence complementation (BiFC) analyses demonstrated interaction of all five Aux/IAA proteins with RUM1 (ROOTLESS WITH UNDETECTABLE MERISTEM 1, ZmIAA10) while only ZmIAA15 and ZmIAA33 interacted with the RUM1 paralog RUL1 (RUM-LIKE 1, ZmIAA29). Moreover, ZmIAA11, ZmIAA15 ZmIAA33 displayed homotypic interaction. Hence, despite their conserved domain structure, maize Aux/IAA proteins display a significant variability in their molecular characteristics which is likely associated with the wide spectrum of their developmental functions. PMID:25203637

  20. Des furoncles résistants aux antibiotiques: penser à la myiase !!

    PubMed Central

    Ajili, Faida; Abid, Rim; Bousseta, Najeh; Mrabet, Ali; Karoui, Ghazi; Louzir, Bassem; Battikh, Riadh; Othmani, Salah

    2013-01-01

    Les myiases sont des infections parasitaires par des larves de mouches. La localisation cutanée doit être évoquée de retour d'un pays tropical devant une évolution inhabituelle de lésions cutanées. Nous rapportons une observation d'un militaire tunisien, ayant séjourné en République Démocratique du Congo. Il était atteint de myiase cutanée simulatrice d'une furonculose résistante aux antibiotiques. L'intérêt de cette observation est de souligner l'importance d’évoquer la myiase dont le traitement est simple et rapide chez un patient de retour de zone d'endémie. PMID:24106569

  1. Soins primaires aux adultes ayant une déficience développementale

    PubMed Central

    Sullivan, William F.; Berg, Joseph M.; Bradley, Elspeth; Cheetham, Tom; Denton, Richard; Heng, John; Hennen, Brian; Joyce, David; Kelly, Maureen; Korossy, Marika; Lunsky, Yona; McMillan, Shirley

    2011-01-01

    Résumé Objectif Mettre à jour les lignes directrices canadiennes de 2006 sur les soins primaires aux adultes ayant une déficience développementale (DD) et présenter des recommandations pratiques fondées sur les connaissances actuelles pour traiter des problèmes de santé particuliers chez des adultes ayant une DD. Qualité des preuves Des professionnels de la santé expérimentés participant à un colloque et un groupe de travail subséquent ont discuté et convenu des révisions aux lignes directrices de 2006 en se fondant sur une recherche documentaire exhaustive, la rétroaction obtenue des utilisateurs du guide de pratique et les expériences cliniques personnelles. La plupart des preuves disponibles dans ce domaine viennent de l’opinion d’experts ou de déclarations consensuelles publiées (niveau III). Message principal Les adultes ayant une DD ont des problèmes de santé complexes, dont plusieurs diffèrent de ceux de la population en général. De bons soins primaires permettent d’identifier les problèmes de santé particuliers dont souffrent les adultes ayant une DD pour améliorer leur qualité de vie et leur accès aux soins de santé et prévenir la morbidité et le décès prématuré. Ces lignes directrices résument les problèmes de santé générale, physique, comportementale et mentale des adultes ayant une DD que devraient connaître les professionnels des soins primaires et présentent des recommandations pour le dépistage et la prise en charge en se basant sur les connaissances actuelles que les cliniciens peuvent mettre en pratique. En raison de l’interaction des facteurs biologiques, psychoaffectifs et sociaux qui contribuent à la santé et au bien-être des adultes ayant une DD, ces lignes directrices insistent sur la participation des aidants, l’adaptation des interventions, au besoin, et la consultation auprès de divers professionnels de la santé quand ils sont accessibles. Elles mettent aussi en évidence la

  2. Negative phototropism is seen in Arabidopsis inflorescences when auxin signaling is reduced to a minimal level by an Aux/IAA dominant mutation, axr2

    PubMed Central

    Sato, Atsuko; Sasaki, Shu; Matsuzaki, Jun; Yamamoto, Kotaro T.

    2015-01-01

    Inflorescences of a dominant mutant of Arabidopsis Aux/IAA7, axr2, showed negative phototropism with a similar fluence response curve to the positive phototropism of wild-type stems. Application of a synthetic auxin, NAA, and an inhibitor of polar auxin transport, NPA, increased and decreased respectively the magnitude of the phototropic response in the wild type, while in axr2 application of NAA reduced the negative phototropic response and NPA had no effect. Decapitation of the apex induced a small negative phototropism in wild-type stems, and had no effect in axr2 plants. Inflorescences of the double mutants of auxin transporters, pgp1 pgp19, showed no phototropic response, while decapitation resulted in a negative phototropic response. These results suggest that negative phototropism can occur when the level of auxin or of auxin signaling is reduced to a minimal level, and that in plant axial organs the default phototropic response to unilateral blue light may be negative. Expression of axr2 protein by an endodermis-specific promoter resulted in agravitropism of inflorescences in a similar way to that of axr2, but phototropism was normal, confirming that the endodermis does not play a critical role in phototropism. PMID:25738325

  3. Negative phototropism is seen in Arabidopsis inflorescences when auxin signaling is reduced to a minimal level by an Aux/IAA dominant mutation, axr2.

    PubMed

    Sato, Atsuko; Sasaki, Shu; Matsuzaki, Jun; Yamamoto, Kotaro T

    2015-01-01

    Inflorescences of a dominant mutant of Arabidopsis Aux/IAA7, axr2, showed negative phototropism with a similar fluence response curve to the positive phototropism of wild-type stems. Application of a synthetic auxin, NAA, and an inhibitor of polar auxin transport, NPA, increased and decreased respectively the magnitude of the phototropic response in the wild type, while in axr2 application of NAA reduced the negative phototropic response and NPA had no effect. Decapitation of the apex induced a small negative phototropism in wild-type stems, and had no effect in axr2 plants. Inflorescences of the double mutants of auxin transporters, pgp1 pgp19, showed no phototropic response, while decapitation resulted in a negative phototropic response. These results suggest that negative phototropism can occur when the level of auxin or of auxin signaling is reduced to a minimal level, and that in plant axial organs the default phototropic response to unilateral blue light may be negative. Expression of axr2 protein by an endodermis-specific promoter resulted in agravitropism of inflorescences in a similar way to that of axr2, but phototropism was normal, confirming that the endodermis does not play a critical role in phototropism. PMID:25738325

  4. Modelisation de la diffusion sur les surfaces metalliques: De l'adatome aux processus de croissance

    NASA Astrophysics Data System (ADS)

    Boisvert, Ghyslain

    Cette these est consacree a l'etude des processus de diffusion en surface dans le but ultime de comprendre, et de modeliser, la croissance d'une couche mince. L'importance de bien mai triser la croissance est primordiale compte tenu de son role dans la miniaturisation des circuits electroniques. Nous etudions ici les surface des metaux nobles et de ceux de la fin de la serie de transition. Dans un premier temps, nous nous interessons a la diffusion d'un simple adatome sur une surface metallique. Nous avons, entre autres, mis en evidence l'apparition d'une correlation entre evenements successifs lorsque la temperature est comparable a la barriere de diffusion, i.e., la diffusion ne peut pas etre associee a une marche aleatoire. Nous proposons un modele phenomenologique simple qui reproduit bien les resultats des simulations. Ces calculs nous ont aussi permis de montrer que la diffusion obeit a la loi de Meyer-Neldel. Cette loi stipule que, pour un processus active, le prefacteur augmente exponentiellement avec la barriere. En plus, ce travail permet de clarifier l'origine physique de cette loi. En comparant les resultats dynamiques aux resultats statiques, on se rend compte que la barriere extraite des calculs dynamiques est essentiellement la meme que celle obtenue par une approche statique, beaucoup plus simple. On peut donc obtenir cette barriere a l'aide de methodes plus precises, i.e., ab initio, comme la theorie de la fonctionnelle de la densite, qui sont aussi malheureusement beaucoup plus lourdes. C'est ce que nous avons fait pour plusieurs systemes metalliques. Nos resultats avec cette derniere approche se comparent tres bien aux resultats experimentaux. Nous nous sommes attardes plus longuement a la surface (111) du platine. Cette surface regorge de particularites interessantes, comme la forme d'equilibre non-hexagonale des i lots et deux sites d'adsorption differents pour l'adatome. De plus, des calculs ab initio precedents n'ont pas reussi a confirmer la

  5. Conséquences comportementales de la violence faite aux enfants

    PubMed Central

    Al Odhayani, Abdulaziz; Watson, William J.; Watson, Lindsay

    2013-01-01

    Résumé Objectif Discuter des répercussions de la violence sur le développement comportemental durant l’enfance, mettre en évidence certains signes comportementaux susceptibles d’alerter les médecins à la présence d’une maltraitance continue d’un enfant et explorer le rôle précis du médecin de famille dans une telle situation clinique. Sources des données Une recension systématique a servi à examiner la recherche pertinente, les articles de révision clinique et les sites web des organismes de protection de la jeunesse. Message principal Le comportement d’un enfant est une manifestation extériorisée de sa stabilité et de sa sécurité intérieures. C’est une lentille au travers de laquelle le médecin de famille peut observer le développement de l’enfant pendant toute sa vie. Tous les genres de violence sont dommageables pour les enfants, qu’elle soit physique, affective ou psychologique, et peuvent causer des problèmes à long terme dans le développement du comportement et de la santé mentale. Les médecins de famille doivent connaître les indices de maltraitance et de négligence envers les enfants et être aux aguets de ces derniers afin d’entreprendre les interventions appropriées et améliorer les résultats pour ces enfants. Conclusion La violence faite aux enfants peut causer un développement psychologique désordonné et des problèmes de comportement. Les médecins de famille exercent un rôle important dans la reconnaissance des signes comportementaux laissant présager une maltraitance, ainsi que pour offrir de l’aide afin de protéger les enfants.

  6. Isolation of PsPIN2 and PsAUX1 from etiolated pea epicotyls and their expression on a three-dimensional clinostat

    NASA Astrophysics Data System (ADS)

    Hoshino, Tomoki; Hitotsubashi, Reiko; Miyamoto, Kensuke; Tanimoto, Eiichi; Ueda, Junichi

    We isolated novel cDNAs containing the complete open reading frames of a putative auxin influx carrier, PsAUX1, and a putative auxin efflux carrier, PsPIN2, from etiolated pea epicotyls. High levels of homology were found on nucleotide and deduced amino acid sequences among PsPIN2, PsPIN1 (Accession No. AY222857) and AtPINs. Phylogenetic analyses based on deduced amino acid sequences revealed that PsPIN2 belonged to a subclade including AtPIN3, AtPIN4 and AtPIN7, while PsPIN1 belonged to the same clade as AtPIN1. The results were similar for PsAUX1 and AtAUX1, where PsAUX1 belongs to the same subclade as AtAUX1 and CS-AUX1. Expression of PsPIN1, PsPIN2 and PsAUX1 in pea epicotyl segments was promoted upon incubation of the segments with auxin (indole-3-acetic acid). In 3.5-d-old etiolated pea seedlings, relatively high expression of PsPIN1 and PsAUX1 was observed in the hook region, growing epicotyls and root tips as compared with those in mature regions of epicotyls and roots. Expression of PsPIN2 in roots was less than that in shoots. Simulated microgravity conditions on a three-dimensional clinostat remarkably increased gene expression of PsPIN1 and PsAUX1 in the hook and the internodes of pea epicotyls, but the increase in PsPIN2 was less. In contrast, polar auxin transport of pea epicotyls was substantially suppressed under simulated microgravity conditions on a 3D clinostat, similar to data from a space experiment on STS-95. These results suggest that PsPINs and PsAUX1 are auxin-inducible genes, and that the expression of PsPINs and PsAUX1 genes is sensitive to gravistimulation.

  7. Periodicity, Electronic Structures, and Bonding of Gold Tetrahalides [AuX4](-) (X = F, CI, Br, I, At, Uus)

    SciTech Connect

    Li, Wan-Lu; Li, Yong; Xu, Congqiao; Wang, Xue B.; Vorpagel, Erich R.; Li, Jun

    2015-12-07

    Systematic theoretical and experimental investigations have been performed to understand the periodicity and electronic structures of trivalent-gold halides using gold tetrahalides [AuX4]⁻ anions (X = F, Cl, Br, I, At, Uus). The [AuX4]⁻ (X = Cl, Br, I) anions were produced in gas phase and their negative-ion photoelectron spectra were obtained, which exhibited rich and well-resolved spectral peaks. We calculated the adiabatic as well as vertical electron detachment energies using density functional methods with scalar and spin-orbit coupling relativistic effects. The simulated photoelectron spectra based on these calculations are in good agreement with the experimental spectra. Our results show that the trivalent Au(III) oxidation state becomes progressively less stable while Au(I) is preferred when the halides become heavier along the Period Table. This trend reveals that the oxidation state of metals in complexes can be manipulated through ligand design

  8. Phloem-specific expression of a melon Aux/IAA in tomato plants alters auxin sensitivity and plant development

    PubMed Central

    Golan, Guy; Betzer, Rotem; Wolf, Shmuel

    2013-01-01

    Phloem sap contains a large repertoire of macromolecules in addition to sugars, amino acids, growth substances and ions. The transcription profile of melon phloem sap contains over 1000 mRNA molecules, most of them associated with signal transduction, transcriptional control, and stress and defense responses. Heterografting experiments have established the long-distance trafficking of numerous mRNA molecules. Interestingly, several trafficking transcripts are involved in the auxin response, including two molecules coding for auxin/indole acetic acid (Aux/IAA). To further explore the biological role of the melon Aux/IAA transcript CmF-308 in the vascular tissue, a cassette containing the coding sequence of this gene under a phloem-specific promoter was introduced into tomato plants. The number of lateral roots was significantly higher in transgenic plants expressing CmF-308 under the AtSUC2 promoter than in controls. A similar effect on root development was obtained after transient expression of CmF-308 in source leaves of N. benthamiana plants. An auxin-response assay showed that CmF-308-transgenic roots are more sensitive to auxin than control roots. In addition to the altered root development, phloem-specific expression of CmF-308 resulted in shorter plants, a higher number of lateral shoots and delayed flowering, a phenotype resembling reduced apical dominance. In contrast to the root response, cotyledons of the transgenic plants were less sensitive to auxin than control cotyledons. The reduced auxin sensitivity in the shoot tissue was confirmed by lower relative expression of several Aux/IAA genes in leaves and an increase in the relative expression of a cytokinin-response regulator, TRR8/9b. The accumulated data suggest that expression of Aux/IAA in the phloem modifies auxin sensitivity in a tissue-specific manner, thereby altering plant development. PMID:23986770

  9. The Tomato Aux/IAA Transcription Factor IAA9 Is Involved in Fruit Development and Leaf MorphogenesisW⃞

    PubMed Central

    Wang, Hua; Jones, Brian; Li, Zhengguo; Frasse, Pierre; Delalande, Corinne; Regad, Farid; Chaabouni, Salma; Latché, Alain; Pech, Jean-Claude; Bouzayen, Mondher

    2005-01-01

    Auxin/indole-3-acetic acid (Aux/IAA) proteins are transcriptional regulators that mediate many aspects of plant responses to auxin. While functions of most Aux/IAAs have been defined mainly by gain-of-function mutant alleles in Arabidopsis thaliana, phenotypes associated with loss-of-function mutations have been scarce and subtle. We report here that the downregulation of IAA9, a tomato (Solanum lycopersicum) gene from a distinct subfamily of Aux/IAA genes, results in a pleiotropic phenotype, consistent with its ubiquitous expression pattern. IAA9-inhibited lines have simple leaves instead of wild-type compound leaves, and fruit development is triggered before fertilization, giving rise to parthenocarpy. This indicates that IAA9 is a key mediator of leaf morphogenesis and fruit set. In addition, antisense plants displayed auxin-related growth alterations, including enhanced hypocotyl/stem elongation, increased leaf vascularization, and reduced apical dominance. Auxin dose–response assays revealed that IAA9 downregulated lines were hypersensitive to auxin, although the only early auxin-responsive gene that was found to be upregulated in the antisense lines was IAA3. The activity of the IAA3 promoter was stimulated in the IAA9 antisense genetic background, indicating that IAA9 acts in planta as a transcriptional repressor of auxin signaling. While no mutation in any member of subfamily IV has been reported to date, the phenotypes associated with the downregulation of IAA9 reveal distinct and novel roles for members of the Aux/IAA gene family. PMID:16126837

  10. Periodicity, Electronic Structures, and Bonding of Gold Tetrahalides [AuX4]- (X = F, Cl, Br, I, At, Uus).

    PubMed

    Li, Wan-Lu; Li, Yong; Xu, Cong-Qiao; Wang, Xue-Bin; Vorpagel, Erich; Li, Jun

    2015-12-01

    Systematic theoretical and experimental investigations have been performed to understand the periodicity, electronic structures, and bonding of gold halides using tetrahalide [AuX4](-) anions (X = F, Cl, Br, I, At, Uus). The [AuX4](-) (X = Cl, Br, I) anions were experimentally produced in the gas phase, and their negative-ion photoelectron spectra were obtained, exhibiting rich and well-resolved spectral peaks. As expected, Au-X bonds in such series contain generally increasing covalency when halogen ligands become heavier. We calculated the adiabatic electron detachment energies as well as vertical electron detachment energies using density functional theory methods with scalar relativistic and spin-orbit coupling effects. The computationally simulated photoelectron spectra are in good agreement with the experimental ones. Our results show that the trivalent Au(III) oxidation state becomes progressively less stable while Au(I) tends to be preferred when the halides become heavier along the Periodic Table. This series of molecules provides an example for manipulating the oxidation state of metals in complexes through ligand design. PMID:26550845

  11. Tectonic conditions of hydrothermal polymetallic vein-type mineralization, Sainte Marie-aux-Mines, France

    NASA Astrophysics Data System (ADS)

    Hafeznia, Y.; Bourlange, S.; Ohnenstetter, M.

    2012-04-01

    The Sainte-Marie-aux-Mines (SMM) mines host one of the most famous and oldest silver deposits in Europe. The SMM district is located in the central part of the Vosges mountains, France, within gneiss and granites of the Moldanubian zone. The SMM district includes the Neuenberg E-W vein-type Cu-Ag-As/Pb-Zn deposit and the Altenberg N-S vein-type Pb-Zn-Ag deposit. Deposition of the SMM hydrothermal mineralization occurred under a brittle tectonic regime that might be connected to neo-Variscan and/or post-Variscan tectonics, in a similar way as the polymetallic vein deposits of the Black Forest, Germany. A structural study was done in the Neuenberg area, in the vicinity of the Saint-Jacques vein, and within the Gabe Gottes mine, considering the orientation, extent, chronology and density of faults as well as the nature of the infilling minerals. In the Gabe-Gottes mine, the Saint-Jacques vein comprises multiple successive, sub-parallel subvertical veinlets with gangue minerals, mostly carbonates and quartz, and metal-bearing phases, sulfides and sulfosalts. The veinlets are 2 to 50 cm thick and strike N80° to N110°, the earlier veins slightly dipping towards the north, and the latest one, to the south. Seven systems of faults were identified, which may be classified into three major groups formed respectively before, during and after the main stage of ore deposition: a) Pre-mineralization faults - These consist of sinistral NE-SW strike-slip faults, and NW-SE and NE-SW steeply dipping normal faults. These could be related to Carboniferous events considering their relationships with the granitoid intrusives present in the mine area (Brézouard leucogranite ~329 Ma), and the extensional tectonics developed during exhumation processes. b) Faults associated with the main ore-deposition - These faults could be related to late-Hercynian processes from compressional to extensional tectonic regimes. Mineralization controlling faults consist of dextral and sinistral E

  12. Réactions immunoallergiques graves aux antibacillaires: à propos de 10 cas

    PubMed Central

    Alami, Sabah El Machichi; Hammi, Sanae; Bourkadi, Jamal Eddine

    2014-01-01

    L'hypersensibilité aux antituberculeux est l'un des effets secondaires imprévisibles qui apparait chez 4 à 5 % de la population exposée et s’élève à 25% chez les sujets VIH positifs. Dans notre étude parmi 39 patients ayant présenté des réactions immunoallergiques, 10 avaient des formes graves. Le délai moyen d'apparition des signes était de 23 jours. Les réactions immunoallergiques observées étaient 5 cas de toxidermie généralisée fébrile, un cas de Dress syndrome, un cas de neutropénie, un cas de pancitopénie et 2 cas de thrombopénie. Tous nos patients avaient bien évolué cliniquement et bactériologiquement après l'adoption d'un régime thérapeutique excluant le ou les médicaments incriminés. En pratique, si l'effet indésirable imputé à un antituberculeux est grave, il est impératif de l'arrêter, de traiter l'incident et d'associer une autre molécule chez certains cas. Notre étude a montré une fréquence significative des complications graves probablement sous-estimée, surtout dans les pays fortement touchés par l'infection HIV.

  13. Genome-wide survey of Aux/IAA gene family members in potato (Solanum tuberosum): Identification, expression analysis, and evaluation of their roles in tuber development.

    PubMed

    Gao, Junpeng; Cao, Xiaoli; Shi, Shandang; Ma, Yuling; Wang, Kai; Liu, Shengjie; Chen, Dan; Chen, Qin; Ma, Haoli

    2016-03-01

    The Auxin/indole-3-acetic acid (Aux/IAA) genes encode short-lived nuclear proteins that are known to be involved in the primary cellular responses to auxin. To date, systematic analysis of the Aux/IAA genes in potato (Solanum tuberosum) has not been conducted. In this study, a total of 26 potato Aux/IAA genes were identified (designated from StIAA1 to StIAA26), and the distribution of four conserved domains shared by the StIAAs were analyzed based on multiple sequence alignment and a motif-based sequence analysis. A phylogenetic analysis of the Aux/IAA gene families of potato and Arabidopsis was also conducted. In order to assess the roles of StIAA genes in tuber development, the results of RNA-seq studies were reformatted to analyze the expression patterns of StIAA genes, and then verified by quantitative real-time PCR. A large number of StIAA genes (12 genes) were highly expressed in stolon organs and in during the tuber initiation and expansion developmental stages, and most of these genes were responsive to indoleacetic acid treatment. Our results suggested that StIAA genes were involved in the process of tuber development and provided insights into functional roles of potato Aux/IAA genes. PMID:26869512

  14. Evaluating auxin distribution in tomato (Solanum lycopersicum) through an analysis of the PIN and AUX/LAX gene families.

    PubMed

    Pattison, Richard J; Catalá, Carmen

    2012-05-01

    The temporal and spatial control of auxin distribution has a key role in the regulation of plant growth and development, and much has been learnt about the mechanisms that influence auxin pools and gradients in vegetative tissues, particularly in Arabidopsis. For example polar auxin transport, mediated by PIN and AUX/LAX proteins, is central to the control of auxin distribution. In contrast, very little information is known about the dynamics of auxin distribution and the molecular basis of its transport within and between fruit tissues, despite the fact that auxin regulates many aspects of fruit development, which include fruit formation, expansion, ripening and abscission. In addition, functional information regarding the key regulators of auxin fluxes during both vegetative and reproductive development in species other than Arabidopsis is scarce. To address these issues, we have investigated the spatiotemporal distribution of auxin during tomato (Solanum lycopersicum) fruit development and the function of the PIN and AUX/LAX gene families. Differential concentrations of auxin become apparent during early fruit growth, with auxin levels being higher in internal tissues than in the fruit pericarp and the pattern of auxin accumulation depended on polar transport. Ten tomato PIN (SlPIN1 to 10) and five AUX/LAX (SlLAX1 to 5) genes were identified and found to display heterogeneous expression patterns, with tissue and developmental-stage specificity. RNAi-mediated co-silencing of SlPIN4 and SlPIN3 did not affect fruit development, which suggested functional redundancy of PIN proteins, but did lead to a vegetative phenotype, and revealed a role for these genes in the regulation of tomato shoot architecture. PMID:22211518

  15. Effect of pH and monovalent cations on the Raman spectrum of water: Basics revisited and application to measure concentration gradients at water/solid interface in Si3N4 biomaterial

    NASA Astrophysics Data System (ADS)

    Pezzotti, Giuseppe; Puppulin, Leonardo; La Rosa, Angelo; Boffelli, Marco; Zhu, Wenliang; McEntire, Bryan J.; Hosogi, Shigekuni; Nakahari, Takashi; Marunaka, Yoshinori

    2015-12-01

    The effect of hydrogen carbonate (HCO3-) and cations (Na+, K+) solvated in water were revisited according to high spectrally resolved Raman measurements. Water solutions with different bicarbonate concentrations or added with increasing amounts of monovalent cations were examined with respect to their Raman spectra both in the bulk state and at the solid/liquid interface with a silicon nitride (Si3N4) bioceramic. Spectroscopic calibrations confirmed that the Raman emission from OH-stretching in water is sensitive to molarity variations (in the order of tens of mM). The concentration gradient developed at the solid/liquid interface in cation-added solutions interacting with a Si3N4 surface was measured and found to be peculiar to individual cations. Local variation in pH was detected in ionic solutions interacting with Si3N4 samples, which might represent a useful property for Si3N4 in a number of biomedical applications.

  16. Approche aux soins en milieu communautaire à des adultes ayant une déficience développementale

    PubMed Central

    Osmun, W.E.; Chan, Nelson; Solomon, Robert

    2015-01-01

    Résumé Objectif Passer en revue les obligations d’ordre médical, éthique et juridique dans les soins aux adultes ayant une déficience développementale (DD) qui vivent dans la communauté. Sources des données Des recherches ont été faites dans Google et MEDLINE à l’aide des mots disabled, disability, vulnerable et community. Les lois pertinentes ont fait l’objet d’un examen. Message principal Le traitement d’un patient ayant une DD varie en fonction de facteurs comme la pathogenèse du problème actuel du patient, ses affections concomitantes, la gravité de ses déficiences et ses soutiens sociaux habituels. Bien que l’on s’entende sur les bienfaits du transfert des soins institutionnels vers des soins communautaires pour les patients ayant une DD, il s’est révélé difficile de leur dispenser des soins de grande qualité en milieu communautaire. Par ailleurs, il existe peu de travaux de recherche sur les façons d’offrir efficacement des soins aux adultes ayant une DD. En tant que professionnels des soins primaires, les médecins de famille sont souvent le premier point de contact pour les patients et sont à la fois responsables de la coordination et de la continuité des soins. Compte tenu de l’importance accrue accordée aux soins préventifs et à la détection précoce des maladies, la participation active du patient revêt aussi une grande importance. Les valeurs et les objectifs du patient sont des éléments essentiels à prendre en compte, même s’ils vont à l’encontre de la bonne santé du patient ou des propres valeurs du clinicien. Les lois s’appliquant aux personnes vulnérables varient d’une province à l’autre. Par conséquent, l’obligation de signaler des mauvais traitements suspectés pourrait différer selon que la personne vulnérable habite dans un centre de soins ou la communauté, que la personne qui soupçonne le comportement abusif est un fournisseur de services ou un professionnel de la santé ou

  17. Light-dependent gravitropism and negative phototropism of inflorescence stems in a dominant Aux/IAA mutant of Arabidopsis thaliana, axr2.

    PubMed

    Sato, Atsuko; Sasaki, Shu; Matsuzaki, Jun; Yamamoto, Kotaro T

    2014-09-01

    Gravitropism and phototropism of the primary inflorescence stems were examined in a dominant Aux/IAA mutant of Arabidopsis, axr2/iaa7, which did not display either tropism in hypocotyls. axr2-1 stems completely lacked gravitropism in the dark but slowly regained it in light condition. Though wild-type stems showed positive phototropism, axr2 stems displayed negative phototropism with essentially the same light fluence-response curve as the wild type (WT). Application of 1-naphthaleneacetic acid-containing lanolin to the stem tips enhanced the positive phototropism of WT, and reduced the negative phototropism of axr2. Decapitation of stems caused a small negative phototropism in WT, but did not affect the negative phototropism of axr2. p-glycoprotein 1 (pgp1) pgp19 double mutants showed no phototropism, while decapitated double mutants exhibited negative phototropism. Expression of auxin-responsive IAA14/SLR, IAA19/MSG2 and SAUR50 genes was reduced in axr2 and pgp1 pgp19 stems relative to that of WT. These suggest that the phototropic response of stem is proportional to the auxin supply from the shoot apex, and that negative phototropism may be a basal response to unilateral blue-light irradiation when the levels of auxin or auxin signaling are reduced to the minimal level in the primary stems. In contrast, all of these treatments reduced or did not affect gravitropism in wild-type or axr2 stems. Tropic responses of the transgenic lines that expressed axr2-1 protein by the endodermis-specific promoter suggest that AXR2-dependent auxin response in the endodermis plays a more crucial role in gravitropism than in phototropism in stems but no significant roles in either tropism in hypocotyls. PMID:24938853

  18. Development of thermal energy storage materials for biomedical applications.

    PubMed

    Shukla, A; Sharma, Atul; Shukla, Manjari; Chen, C R

    2015-01-01

    The phase change materials (PCMs) have been utilized widely for solar thermal energy storage (TES) devices. The quality of these materials to remain at a particular temperature during solid-liquid, liquid-solid phase transition can also be utilized for many biomedical applications as well and has been explored in recent past already. This study reports some novel PCMs developed by them, along with some existing PCMs, to be used for such biomedical applications. Interestingly, it was observed that the heating/cooling properties of these PCMs enhance the quality of a variety of biomedical applications with many advantages (non-electric, no risk of electric shock, easy to handle, easy to recharge thermally, long life, cheap and easily available, reusable) over existing applications. Results of the present study are quite interesting and exciting, opening a plethora of opportunities for more work on the subject, which require overlapping expertise of material scientists, biochemists and medical experts for broader social benefits. PMID:26103988

  19. Residus de 2-formes differentielles sur les surfaces algebriques et applications aux codes correcteurs d'erreurs

    NASA Astrophysics Data System (ADS)

    Couvreur, A.

    2009-05-01

    The theory of algebraic-geometric codes has been developed in the beginning of the 80's after a paper of V.D. Goppa. Given a smooth projective algebraic curve X over a finite field, there are two different constructions of error-correcting codes. The first one, called "functional", uses some rational functions on X and the second one, called "differential", involves some rational 1-forms on this curve. Hundreds of papers are devoted to the study of such codes. In addition, a generalization of the functional construction for algebraic varieties of arbitrary dimension is given by Y. Manin in an article of 1984. A few papers about such codes has been published, but nothing has been done concerning a generalization of the differential construction to the higher-dimensional case. In this thesis, we propose a differential construction of codes on algebraic surfaces. Afterwards, we study the properties of these codes and particularly their relations with functional codes. A pretty surprising fact is that a main difference with the case of curves appears. Indeed, if in the case of curves, a differential code is always the orthogonal of a functional one, this assertion generally fails for surfaces. Last observation motivates the study of codes which are the orthogonal of some functional code on a surface. Therefore, we prove that, under some condition on the surface, these codes can be realized as sums of differential codes. Moreover, we show that some answers to some open problems "a la Bertini" could give very interesting informations on the parameters of these codes.

  20. Probing the structures of gold-aluminum alloy clusters AuxAly-: a joint experimental and theoretical study

    NASA Astrophysics Data System (ADS)

    Khetrapal, Navneet Singh; Jian, Tian; Pal, Rhitankar; Lopez, Gary V.; Pande, Seema; Wang, Lai-Sheng; Zeng, Xiao Cheng

    2016-05-01

    Besides the size and structure, compositions can also dramatically affect the properties of alloy nanoclusters. Due to the added degrees of freedom, determination of the global minimum structures for multi-component nanoclusters poses even greater challenges, both experimentally and theoretically. Here we report a systematic and joint experimental/theoretical study of a series of gold-aluminum alloy clusters, AuxAly- (x + y = 7,8), with various compositions (x = 1-3 y = 4-7). Well-resolved photoelectron spectra have been obtained for these clusters at different photon energies. Basin-hopping global searches, coupled with density functional theory calculations, are used to identify low-lying structures of the bimetallic clusters. By comparing computed electronic densities of states of the low-lying isomers with the experimental photoelectron spectra, the global minima are determined. It is found that for y >= 6 there is a strong tendency to form the magic-number square bi-pyramid motif of Al6- in the AuxAly- clusters, suggesting that the Al-Al interaction dominates the Au-Au interaction in the mixed clusters. A closely related trend is that for x > 1, the gold atoms tend to be separated by Al atoms unless only the magic-number Al6- square bi-pyramid motif is present, suggesting that in the small-sized mixed clusters, Al and Au components do not completely mix with one another. Overall, the Al component appears to play a more dominant role due to the high robustness of the magic-number Al6- square bi-pyramid motif, whereas the Au component tends to be either ``adsorbed'' onto the Al6- square bi-pyramid motif if y >= 6, or stays away from one another if x < y < 6.Besides the size and structure, compositions can also dramatically affect the properties of alloy nanoclusters. Due to the added degrees of freedom, determination of the global minimum structures for multi-component nanoclusters poses even greater challenges, both experimentally and theoretically. Here we

  1. The auxin transporter, OsAUX1, is involved in primary root and root hair elongation and in Cd stress responses in rice (Oryza sativa L.).

    PubMed

    Yu, ChenLiang; Sun, ChenDong; Shen, Chenjia; Wang, Suikang; Liu, Fang; Liu, Yan; Chen, YunLong; Li, Chuanyou; Qian, Qian; Aryal, Bibek; Geisler, Markus; Jiang, De An; Qi, YanHua

    2015-09-01

    Auxin and cadmium (Cd) stress play critical roles during root development. There are only a few reports on the mechanisms by which Cd stress influences auxin homeostasis and affects primary root (PR) and lateral root (LR) development, and almost nothing is known about how auxin and Cd interfere with root hair (RH) development. Here, we characterize rice osaux1 mutants that have a longer PR and shorter RHs in hydroponic culture, and that are more sensitive to Cd stress compared to wild-type (Dongjin). OsAUX1 expression in root hair cells is different from that of its paralogous gene, AtAUX1, which is expressed in non-hair cells. However, OsAUX1, like AtAUX1, localizes at the plasma membrane and appears to function as an auxin tranporter. Decreased auxin distribution and contents in the osaux1 mutant result in reduction of OsCyCB1;1 expression and shortened PRs, LRs and RHs under Cd stress, but may be rescued by treatment with the membrane-permeable auxin 1-naphthalene acetic acid. Treatment with the auxin transport inhibitors 1-naphthoxyacetic acid and N-1-naphthylphthalamic acid increased the Cd sensitivity of WT rice. Cd contents in the osaux1 mutant were not altered, but reactive oxygen species-mediated damage was enhanced, further increasing the sensitivity of the osaux1 mutant to Cd stress. Taken together, our results indicate that OsAUX1 plays an important role in root development and in responses to Cd stress. PMID:26140668

  2. Diversification and Expression of the PIN, AUX/LAX, and ABCB Families of Putative Auxin Transporters in Populus

    PubMed Central

    Carraro, Nicola; Tisdale-Orr, Tracy Eizabeth; Clouse, Ronald Matthew; Knöller, Anne Sophie; Spicer, Rachel

    2012-01-01

    Intercellular transport of the plant hormone auxin is mediated by three families of membrane-bound protein carriers, with the PIN and ABCB families coding primarily for efflux proteins and the AUX/LAX family coding for influx proteins. In the last decade our understanding of gene and protein function for these transporters in Arabidopsis has expanded rapidly but very little is known about their role in woody plant development. Here we present a comprehensive account of all three families in the model woody species Populus, including chromosome distribution, protein structure, quantitative gene expression, and evolutionary relationships. The PIN and AUX/LAX gene families in Populus comprise 16 and 8 members respectively and show evidence for the retention of paralogs following a relatively recent whole genome duplication. There is also differential expression across tissues within many gene pairs. The ABCB family is previously undescribed in Populus and includes 20 members, showing a much deeper evolutionary history, including both tandem and whole genome duplication as well as probable gene loss. A striking number of these transporters are expressed in developing Populus stems and we suggest that evolutionary and structural relationships with known auxin transporters in Arabidopsis can point toward candidate genes for further study in Populus. This is especially important for the ABCBs, which is a large family and includes members in Arabidopsis that are able to transport other substrates in addition to auxin. Protein modeling, sequence alignment and expression data all point to ABCB1.1 as a likely auxin transport protein in Populus. Given that basipetal auxin flow through the cambial zone shapes the development of woody stems, it is important that we identify the full complement of genes involved in this process. This work should lay the foundation for studies targeting specific proteins for functional characterization and in situ localization. PMID:22645571

  3. Probing the structures of gold-aluminum alloy clusters AuxAly(-): a joint experimental and theoretical study.

    PubMed

    Khetrapal, Navneet Singh; Jian, Tian; Pal, Rhitankar; Lopez, Gary V; Pande, Seema; Wang, Lai-Sheng; Zeng, Xiao Cheng

    2016-05-01

    Besides the size and structure, compositions can also dramatically affect the properties of alloy nanoclusters. Due to the added degrees of freedom, determination of the global minimum structures for multi-component nanoclusters poses even greater challenges, both experimentally and theoretically. Here we report a systematic and joint experimental/theoretical study of a series of gold-aluminum alloy clusters, AuxAly(-) (x + y = 7,8), with various compositions (x = 1-3; y = 4-7). Well-resolved photoelectron spectra have been obtained for these clusters at different photon energies. Basin-hopping global searches, coupled with density functional theory calculations, are used to identify low-lying structures of the bimetallic clusters. By comparing computed electronic densities of states of the low-lying isomers with the experimental photoelectron spectra, the global minima are determined. It is found that for y ≥ 6 there is a strong tendency to form the magic-number square bi-pyramid motif of Al6(-) in the AuxAly(-) clusters, suggesting that the Al-Al interaction dominates the Au-Au interaction in the mixed clusters. A closely related trend is that for x > 1, the gold atoms tend to be separated by Al atoms unless only the magic-number Al6(-) square bi-pyramid motif is present, suggesting that in the small-sized mixed clusters, Al and Au components do not completely mix with one another. Overall, the Al component appears to play a more dominant role due to the high robustness of the magic-number Al6(-) square bi-pyramid motif, whereas the Au component tends to be either "adsorbed" onto the Al6(-) square bi-pyramid motif if y ≥ 6, or stays away from one another if x < y < 6. PMID:27119726

  4. Irrepressible, truncated auxin response factors: natural roles and applications in dissecting auxin gene regulation pathways.

    PubMed

    Ckurshumova, Wenzislava; Krogan, Naden T; Marcos, Danielle; Caragea, Adriana E; Berleth, Thomas

    2012-08-01

    The molecularly well-characterized auxin signal transduction pathway involves two evolutionarily conserved families interacting through their C-terminal domains III and IV: the Auxin Response Factors (ARFs) and their repressors the Aux/IAAs, to control auxin-responsive genes, among them genes involved in auxin transport. ( 1) (,) ( 2) We have developed a new genetic tool to study ARF function. Using MONOPTEROS (MP)/ARF5, we have generated a truncated version of MP (MPΔ), ( 3) which has lost the target domains for repression by Aux/IAA proteins. Besides exploring genetic interactions between MP and Aux/IAAs, we used this construct to trace MP's role in vascular patterning, a previously characterized auxin dependent process. ( 4) (,) ( 5) Here we summarize examples of naturally occurring truncated ARFs and summarize potential applications of truncated ARFs as analytical tools. PMID:22827953

  5. Instrument Turns Sound of Music to Sight of Music at Aux Chandelles

    ERIC Educational Resources Information Center

    Educ Media, 1970

    1970-01-01

    Described are some of the applications found in teaching retarded children for the Dynalevel, an instrument which "transforms the loudness of sound into light to provide a visual check on the tone intensity. (Author/LS)

  6. Arabidopsis SHR and SCR transcription factors and AUX1 auxin influx carrier control the switch between adventitious rooting and xylogenesis in planta and in in vitro cultured thin cell layers

    PubMed Central

    Della Rovere, F.; Fattorini, L.; D’Angeli, S.; Veloccia, A.; Del Duca, S.; Cai, G.; Falasca, G.; Altamura, M. M.

    2015-01-01

    Background and Aims Adventitious roots (ARs) are essential for vegetative propagation. The Arabidopsis thaliana transcription factors SHORT ROOT (SHR) and SCARECROW (SCR) affect primary/lateral root development, but their involvement in AR formation is uncertain. LAX3 and AUX1 auxin influx carriers contribute to primary/lateral root development. LAX3 expression is regulated by SHR, and LAX3 contributes to AR tip auxin maximum. In contrast, AUX1 involvement in AR development is unknown. Xylogenesis is induced by auxin plus cytokinin as is AR formation, but the genes involved are largely unknown. Stem thin cell layers (TCLs) form ARs and undergo xylogenesis under the same auxin plus cytokinin input. The aim of this research was to investigate SHR, SCR, AUX1 and LAX3 involvement in AR formation and xylogenesis in intact hypocotyls and stem TCLs in arabidopsis. Methods Hypocotyls of scr-1, shr-1, lax3, aux1-21 and lax3/aux1-21 Arabidopsis thaliana null mutant seedlings grown with or without auxin plus cytokinin were examined histologically, as were stem TCLs cultured with auxin plus cytokinin. SCR and AUX1 expression was monitored using pSCR::GFP and AUX1::GUS lines, and LAX3 expression and auxin localization during xylogenesis were monitored by using LAX3::GUS and DR5::GUS lines. Key Results AR formation was inhibited in all mutants, except lax3. SCR was expressed in pericycle anticlinally derived AR-forming cells of intact hypocotyls, and in cell clumps forming AR meristemoids of TCLs. The apex was anomalous in shr and scr ARs. In all mutant hypocotyls, the pericycle divided periclinally to produce xylogenesis. Xylary element maturation was favoured by auxin plus cytokinin in shr and aux1-21. Xylogenesis was enhanced in TCLs, and in aux1-21 and shr in particular. AUX1 was expressed before LAX3, i.e. in the early derivatives leading to either ARs or xylogenesis. Conclusions AR formation and xylogenesis are developmental programmes that are inversely related, but they

  7. Convection effects at solid-liquid interfaces: Influence of gravity

    NASA Technical Reports Server (NTRS)

    Glicksman, M. E.; Fang, Q. T.; Coriell, S. R.; Boisvert, R. F.

    1983-01-01

    The stability of the flow between two vertical, infinite, rigid, coaxial cylinders held at different temperatures is analyzed by linear stability theory. For a Prandtl number of 22.8 and a radius ratio of 0.02, the flow is unstable to an axisymmetric perturbation at a critical Grashof number of 2150; the wave speed of the instability is comparable to the maximum velocity of the unperturbed flow. When the rigid outer cylinder-fluid interface is replaced by a crystal-melt interface which can change shape, two new modes of instability occur at lower Grashof numbers.

  8. Atomic Resolution Images of Solid-Liquid Interfaces

    NASA Astrophysics Data System (ADS)

    Giambattista, Brian; McNairy, W. W.; Slough, C. G.; Johnson, A.; Bell, L. D.; Coleman, R. V.; Schneir, J.; Sonnenfeld, R.; Drake, B.; Hansma, P. K.

    1987-07-01

    A scanning tunneling microscope (STM) can provide atomic-resolution images of solids covered with a variety of liquids, including cryogenic fluids, both polar and nonpolar solvents, conductive aqueous solutions, oils, and even greases. This short overview includes images of solids covered with liquid nitrogen, liquid helium, paraffin oil, silicone oil, microscope immersion oil, silicone vacuum grease, fluorocarbon grease, glycerol, and salt water. These images show atoms, charge-density waves, grains in an evaporated metal film, and even corrosion processes as they occur in real time. The future includes not only basic research in surface science but also applied research in lithography, lubrication, catalysis, corrosion, electrochemistry, and perhaps even biology.

  9. Adsorption of nanoparticles at the solid-liquid interface.

    PubMed

    Brenner, Thorsten; Paulus, Michael; Schroer, Martin A; Tiemeyer, Sebastian; Sternemann, Christian; Möller, Johannes; Tolan, Metin; Degen, Patrick; Rehage, Heinz

    2012-05-15

    The adsorption of differently charged nanoparticles at liquid-solid interfaces was investigated by in situ X-ray reflectivity measurements. The layer formation of positively charged maghemite (γ-Fe(2)O(3)) nanoparticles at the aqueous solution-SiO(2) interface was observed while negatively charged gold nanoparticles show no adsorption at this interface. Thus, the electrostatic interaction between the particles and the charged surface was determined as the driving force for the adsorption process. The data analysis shows that a logarithmic particle size distribution describes the density profile of the thin adsorbed maghemite layer. The size distribution in the nanoparticle solution determined by small angle X-ray scattering shows an average particle size which is similar to that found for the adsorbed film. The formed magehemite film exhibits a rather high stability. PMID:22386203

  10. Supersonic Air Flow due to Solid-Liquid Impact

    NASA Astrophysics Data System (ADS)

    Gekle, Stephan; Peters, Ivo R.; Gordillo, José Manuel; van der Meer, Devaraj; Lohse, Detlef

    2010-01-01

    A solid object impacting on liquid creates a liquid jet due to the collapse of the impact cavity. Using visualization experiments with smoke particles and multiscale simulations, we show that in addition, a high-speed air jet is pushed out of the cavity. Despite an impact velocity of only 1m/s, this air jet attains supersonic speeds already when the cavity is slightly larger than 1 mm in diameter. The structure of the air flow closely resembles that of compressible flow through a nozzle—with the key difference that here the “nozzle” is a liquid cavity shrinking rapidly in time.

  11. Intrinsically Stretchable Biphasic (Solid-Liquid) Thin Metal Films.

    PubMed

    Hirsch, Arthur; Michaud, Hadrien O; Gerratt, Aaron P; de Mulatier, Séverine; Lacour, Stéphanie P

    2016-06-01

    Stretchable biphasic conductors are formed by physical vapor deposition of gallium onto an alloying metal film. The properties of the photolithography-compatible thin metal films are highlighted by low sheet resistance (0.5 Ω sq(-1) ) and large stretchability (400%). This novel approach to deposit and pattern liquid metals enables extremely robust, multilayer and soft circuits, sensors, and actuators. PMID:26923313

  12. Intermediate couplings: NMR at the solids-liquids interface

    NASA Astrophysics Data System (ADS)

    Spence, Megan

    2006-03-01

    Anisotropic interactions like dipolar couplings and chemical shift anisotropy have long offered solid-state NMR spectroscopists valuable structural information. Recently, solution-state NMR structural studies have begun to exploit residual dipolar couplings of biological molecules in weakly anisotropic solutions. These residual couplings are about 0.1% of the coupling magnitudes observed in the solid state, allowing simple, high-resolution NMR spectra to be retained. In this work, we examine the membrane-associated opioid, leucine enkephalin (lenk), in which the ordering is ten times larger than that for residual dipolar coupling experiments, requiring a combination of solution-state and solid-state NMR techniques. We adapted conventional solid-state NMR techniques like adiabatic cross- polarization and REDOR for use with such a system, and measured small amide bond dipolar couplings in order to determine the orientation of the amide bonds (and therefore the peptide) with respect to the membrane surface. However, the couplings measured indicate large structural rearrangements on the surface and contradict the published structures obtained by NOESY constraints, a reminder that such methods are of limited use in the presence of large-scale dynamics.

  13. Manifold to uniformly distribute a solid-liquid slurry

    DOEpatents

    Kern, Kenneth C.

    1983-01-01

    This invention features a manifold that divides a stream of coal particles and liquid into several smaller streams maintaining equal or nearly equal mass compositions. The manifold consists of a horizontal, variable area header having sharp-edged, right-angled take-offs which are oriented on the bottom of the header.

  14. The French Tsunami warning center for the Mediterranean and North-East Atlantic (CENtre d'ALerte aux Tsunamis, CENALT)

    NASA Astrophysics Data System (ADS)

    Schindelé, F.; Bossu, R.; Alabrune, N.; Arnoul, P.; Duperray, P.; Gailler, A.; Guilbert, J.; Hébert, H.; Hernandez, B.; Loevenbruck, A.; Roudil, P.

    2012-04-01

    The CENALT (CENtre d'Alerte aux Tsunamis) is responsible for the French NTWC (National Tsunami Warning Center). This center was established through a project that was requested by the French Ministry of Interior and the Ministry of Sustainable Development. It is implemented by the Commissariat à l'énergie atomique et aux énergies alternatives (CEA), the French Hydrographic and Oceanographic Service (SHOM) and the Centre National de la Recherche Scientifique (CNRS), and is based in Bruyères-le-Châtel (30 km from Paris). This center is based on three main components: seismic network data, sea level network data, dissemination system and processing and analyzing softwares and is operating on a 24/7 basis. The CENALT has established scientific cooperation with 8 institutions and implemented and funded private leased lines to exchange data with institutions from 5 different European countries (Germany, Italy, Portugal, Spain, Tunisia). The seismic data are processed with the Seiscomp 3 software. SHOM is working on making all French tide-gauge stations operated and available in real-time in 2012, and they installed 5 new tide gage stations. The tide gage data will be processed with a customized version of the Guitar (Gempa) software allowing the detection of tsunami signals, complemented by other softwares developed by the CEA. Historical tsunami databases (sources and observations) and earthquake databases, mostly based on available international databases, have been synthetized by CEA to produce information maps in real time, used to guide operators of permanence. Precomputed tsunami scenarios are implemented to build in real time maps of the highest tsunami impact expected in deep water. Along with an optimized tsunami modeling tool, these softwares help to define the areas where the tsunami may be observed and cause damage. The CENALT has been operating since early January 2012 as a pre-operational service and will be fully operational in July 2012. It is also

  15. Le système opioïde endogène et l’addiction aux drogues1

    PubMed Central

    Maldonado, Rafael

    2010-01-01

    Résumé L’addiction aux drogues est une maladie psychiatrique chronique qui conduit à d’importantes altérations adaptatives dans les circuits de récompense du cerveau. Plusieurs systèmes de neurotransmission sont impliqués dans ces modifications. Cependant, un des systèmes neurochimiques qui joue un rôle essentiel dans l’addiction est le système opioïde endogène. Les récepteurs opioïdes et les peptides opioïdes endogènes sont très largement présents dans les structures cérébrales qui contrôlent les phénomènes de récompense, en particulier le système mésolimbique. Ces récepteurs et peptides opioïdes participent d’une manière sélective à plusieurs aspects des processus addictifs induits par les opiacés, les cannabinoïdes, les psychostimulants, l’alcool et la nicotine. Cette revue rend compte de l’état actuel des connaissances sur la participation de chaque composante du système opioïde endogène dans les propriétés addictives des différentes drogues. PMID:20176158

  16. Gestion des ressources hydriques adaptee aux changements climatiques pour la production optimale d'hydroelectricite. Etude de cas: Bassin versant de la riviere Manicouagan

    NASA Astrophysics Data System (ADS)

    Haguma, Didier

    Il est dorenavant etabli que les changements climatiques auront des repercussions sur les ressources en eau. La situation est preoccupante pour le secteur de production d'energie hydroelectrique, car l'eau constitue le moteur pour generer cette forme d'energie. Il sera important d'adapter les regles de gestion et/ou les installations des systemes hydriques, afin de minimiser les impacts negatifs et/ou pour capitaliser sur les retombees positives que les changements climatiques pourront apporter. Les travaux de la presente recherche s'interessent au developpement d'une methode de gestion des systemes hydriques qui tient compte des projections climatiques pour mieux anticiper les impacts de l'evolution du climat sur la production d'hydroelectricite et d'etablir des strategies d'adaptation aux changements climatiques. Le domaine d'etude est le bassin versant de la riviere Manicouagan situe dans la partie centrale du Quebec. Une nouvelle approche d'optimisation des ressources hydriques dans le contexte des changements climatiques est proposee. L'approche traite le probleme de la saisonnalite et de la non-stationnarite du climat d'une maniere explicite pour representer l'incertitude rattachee a un ensemble des projections climatiques. Cette approche permet d'integrer les projections climatiques dans le probleme d'optimisation des ressources en eau pour une gestion a long terme des systemes hydriques et de developper des strategies d'adaptation de ces systemes aux changements climatiques. Les resultats montrent que les impacts des changements climatiques sur le regime hydrologique du bassin de la riviere Manicouagan seraient le devancement et l'attenuation de la crue printaniere et l'augmentation du volume annuel d'apports. L'adaptation des regles de gestion du systeme hydrique engendrerait une hausse de la production hydroelectrique. Neanmoins, une perte de la performance des installations existantes du systeme hydrique serait observee a cause de l'augmentation des

  17. Absolute NMR shielding scales and nuclear spin–rotation constants in {sup 175}LuX and {sup 197}AuX (X = {sup 19}F, {sup 35}Cl, {sup 79}Br and {sup 127}I)

    SciTech Connect

    Demissie, Taye B. Komorovsky, Stanislav; Repisky, Michal; Ruud, Kenneth; Jaszuński, Michał

    2015-10-28

    We present nuclear spin–rotation constants, absolute nuclear magnetic resonance (NMR) shielding constants, and shielding spans of all the nuclei in {sup 175}LuX and {sup 197}AuX (X = {sup 19}F, {sup 35}Cl, {sup 79}Br, {sup 127}I), calculated using coupled-cluster singles-and-doubles with a perturbative triples (CCSD(T)) correction theory, four-component relativistic density functional theory (relativistic DFT), and non-relativistic DFT. The total nuclear spin–rotation constants determined by adding the relativistic corrections obtained from DFT calculations to the CCSD(T) values are in general in agreement with available experimental data, indicating that the computational approach followed in this study allows us to predict reliable results for the unknown spin–rotation constants in these molecules. The total NMR absolute shielding constants are determined for all the nuclei following the same approach as that applied for the nuclear spin–rotation constants. In most of the molecules, relativistic effects significantly change the computed shielding constants, demonstrating that straightforward application of the non-relativistic formula relating the electronic contribution to the nuclear spin–rotation constants and the paramagnetic contribution to the shielding constants does not yield correct results. We also analyze the origin of the unusually large absolute shielding constant and its relativistic correction of gold in AuF compared to the other gold monohalides.

  18. Absolute NMR shielding scales and nuclear spin-rotation constants in (175)LuX and (197)AuX (X = (19)F, (35)Cl, (79)Br and (127)I).

    PubMed

    Demissie, Taye B; Jaszuński, Michał; Komorovsky, Stanislav; Repisky, Michal; Ruud, Kenneth

    2015-10-28

    We present nuclear spin-rotation constants, absolute nuclear magnetic resonance (NMR) shielding constants, and shielding spans of all the nuclei in (175)LuX and (197)AuX (X = (19)F, (35)Cl, (79)Br, (127)I), calculated using coupled-cluster singles-and-doubles with a perturbative triples (CCSD(T)) correction theory, four-component relativistic density functional theory (relativistic DFT), and non-relativistic DFT. The total nuclear spin-rotation constants determined by adding the relativistic corrections obtained from DFT calculations to the CCSD(T) values are in general in agreement with available experimental data, indicating that the computational approach followed in this study allows us to predict reliable results for the unknown spin-rotation constants in these molecules. The total NMR absolute shielding constants are determined for all the nuclei following the same approach as that applied for the nuclear spin-rotation constants. In most of the molecules, relativistic effects significantly change the computed shielding constants, demonstrating that straightforward application of the non-relativistic formula relating the electronic contribution to the nuclear spin-rotation constants and the paramagnetic contribution to the shielding constants does not yield correct results. We also analyze the origin of the unusually large absolute shielding constant and its relativistic correction of gold in AuF compared to the other gold monohalides. PMID:26520517

  19. Absolute NMR shielding scales and nuclear spin-rotation constants in 175LuX and 197AuX (X = 19F, 35Cl, 79Br and 127I)

    NASA Astrophysics Data System (ADS)

    Demissie, Taye B.; Jaszuński, Michał; Komorovsky, Stanislav; Repisky, Michal; Ruud, Kenneth

    2015-10-01

    We present nuclear spin-rotation constants, absolute nuclear magnetic resonance (NMR) shielding constants, and shielding spans of all the nuclei in 175LuX and 197AuX (X = 19F, 35Cl, 79Br, 127I), calculated using coupled-cluster singles-and-doubles with a perturbative triples (CCSD(T)) correction theory, four-component relativistic density functional theory (relativistic DFT), and non-relativistic DFT. The total nuclear spin-rotation constants determined by adding the relativistic corrections obtained from DFT calculations to the CCSD(T) values are in general in agreement with available experimental data, indicating that the computational approach followed in this study allows us to predict reliable results for the unknown spin-rotation constants in these molecules. The total NMR absolute shielding constants are determined for all the nuclei following the same approach as that applied for the nuclear spin-rotation constants. In most of the molecules, relativistic effects significantly change the computed shielding constants, demonstrating that straightforward application of the non-relativistic formula relating the electronic contribution to the nuclear spin-rotation constants and the paramagnetic contribution to the shielding constants does not yield correct results. We also analyze the origin of the unusually large absolute shielding constant and its relativistic correction of gold in AuF compared to the other gold monohalides.

  20. Algorithme d'adaptation du filtre de Kalman aux variations soudaines de bruit

    NASA Astrophysics Data System (ADS)

    Canciu, Vintila

    This research targets the case of Kalman filtering as applied to linear time-invariant systems having unknown process noise covariance and measurement noise covariance matrices and addresses the problem represented by the incomplete a priori knowledge of these two filter initialization parameters. The goal of this research is to determine in realtime both the process covariance matrix and the noise covariance matrix in the context of adaptive Kalman filtering. The resultant filter, called evolutionary adaptive Kalman filter, is able to adapt to sudden noise variations and constitutes a hybrid solution for adaptive Kalman filtering based on metaheuristic algorithms. MATLAB/Simulink simulation using several processes and covariance matrices plus comparison with other filters was selected as validation method. The Cramer-Rae Lower Bound (CRLB) was used as performance criterion. The thesis begins with a description of the problem under consideration (the design of a Kalman filter that is able to adapt to sudden noise variations) followed by a typical application (INS-GPS integrated navigation system) and by a statistical analysis of publications related to adaptive Kalman filtering. Next, the thesis presents the current architectures of the adaptive Kalman filtering: the innovation adaptive estimator (IAE) and the multiple model adaptive estimator (MMAE). It briefly presents their formulation, their behavior, and the limit of their performances. The thesis continues with the architectural synthesis of the evolutionary adaptive Kalman filter. The steps involved in the solution of the problem under consideration is also presented: an analysis of Kalman filtering and sub-optimal filtering methods, a comparison of current adaptive Kalman and sub-optimal filtering methods, the emergence of evolutionary adaptive Kalman filter as an enrichment of sub-optimal filtering with the help of biological-inspired computational intelligence methods, and the step-by-step architectural

  1. Acquisition de donnees a haute resolution et faible latence dediee aux capteurs avioniques de position

    NASA Astrophysics Data System (ADS)

    Koubaa, Zied

    The communication network and the detection mechanisms are two critical systems in a plane. Their performance has a direct impact on aircrafts. This is of particular interest for avionics designers, who have increasingly invested more and more in the development of these elements. As a part of a project in this domain, we introduce the design and the development of a smart interface for position sensors dedicated to flights (Smart Sensor Interface - SSI). This interface will serve to connect sensors of different technologies (electromagnetic, optical and MEMS) to the new communication network, AFDX. The role of this interface is to generate an appropriate excitation signal for certain types of sensors (R/LVDT), and to treat, demodulate, and digitize their output signals. The proposed interface is thus composed of a Signal Acquisition Path (SAP) and an Excitation Signal Generation (ESG). By adopting the Integrated Modular Avionics architecture (IMA), we can minimize the size of the classic interface, reduce its energy consumption and improve its reliability and its performance. The focus of our design is particularly on the Data Acquisition Path (DAP). An Architecture characterized by a high resolution (14 bits) and a low latency (1.2 ms) of this module is introduced and developed in this prestigious work. This architecture was developed after a wellconducted study of existing solutions found in literature work and a detailed analysis of the problems arise in the design and implementation of this system (DAP). The conversion of the sensor signal into a digital signal is the most important step in acquiring data, as it sets the resolution of the acquired information and generates the majority of its latency. This module can also affect the reliability and stability of the system. Among different models and architectures, the Delta-Sigma analog-to-digital converter (ADC) is preferred for this application (for better resolution). This converter is formed by an analog

  2. Complex facies relationships and regional stratigraphy of the Mississippian Ste. Genevieve, Paoli, and Aux Vases Formations, Illinois basin: A major hydrocarbon-producing interval

    SciTech Connect

    Cole, R.D.; Nelson, W.J. )

    1993-03-01

    The Mississippian Ste. Genevieve and Paoli Limestones and sandstones of the Aux Vases Formation are lateral facies of one another. This interpretation is based on comprehensive investigations of outcrops, and selected cores, samples of well cuttings, and geophysical logs conducted over a period of four years. Both units exhibit similar sedimentological characteristics and represent open marine, shallow subtidal, and intertidal environments. The presence of low-angle cross-laminae, ripple- and plane-laminae, climbing ripples, and ooid shoals suggest most deposition occurred under low energy conditions. Lenticular, channel-like scour and fill structures that contain both fine-grained quartz sand and abraded, disarticulated fossil fragments indicate localized higher energy deposition. The authors studies indicate that siliciclastic vs. carbonate deposition was controlled strictly by available sediment, and not by regressive (siliciclastic) and transgressive (carbonate) events, as inferred by previous workers. This conclusion is based on lateral facies relationships, and the supplanting of carbonates by clastics occurring in the upper part of the Ste. Genevieve through the middle part of the Paoli. The Aux Vases is thickest, coarsest, and least mature in the northwestern part of the Illinois Basin, and pinches out to the southeast. This implies a northwesterly source for clastics, perhaps the Transcontinental Arch. After early Chesterian time, the Transcontinental Arch apparently supplied little or no sediment to any flanking basin. The Ste. Genevieve, Paoli, and Aux Vases are major oil-producing units in the Illinois Basin. New understanding of regional relationships should enhance exploratory success and improve recovery from established fields.

  3. Niveau socioéconomique et processus du recours aux soins par les familles de patients souffrant de troubles psychiques au Burkina Faso

    PubMed Central

    Yaogo, Ahmed; Sommer, Alain; Moulaï, Pierre; Chebili, Saïd; Abaoub-Germain, Agnès

    2014-01-01

    Introduction Le Burkina Faso a connu une amélioration constante depuis deux décennies de l'offre de soins en psychiatrie. De même, le taux d'alphabétisation sans cesse croissant s'accompagne d'une profonde modification des conceptions et des comportements. La présente étude visait à déterminer l′impact des déterminants socioéconomiques sur le processus du recours aux soins par les familles. Méthodes Il s'est agi d'une enquête transversale portant sur 200 familles, menée dans le service de psychiatrie du Centre Hospitalier Universitaire Yalgado Ouédraogo de Ouagadougou. Variable à expliquer: premier recours aux soins par les familles (guérisseur traditionnel ou prières religieuses vs. consultations psychiatrique ou médicale). Variable explicative: catégorie socioprofessionnelle classée en suivant la nomenclature des professions et catégories socioprofessionnelles; niveau d’études. L'analyse statistique a été effectuée à l'aide du logiciel SAS version 9.2. Le test du Khi deux a été utilisé. Résultats Il existait une association entre le choix du premier recours et la Profession et la catégorie socioprofessionnelledu « décideur » (p = 0.0006) ainsi que leniveau d’études du « décideur » (p = 0.0001). Conclusion La Profession et Catégorie Sociale et le niveau d'instruction scolaire pourraient être un marqueur important dans les politiques visant à optimiser les processus de recours aux soins des patients dans le circuit de soins. PMID:25161751

  4. Phase relations in the system NaCl-KCl-H2O: IV. Differential thermal analysis of the sylvite liquidus in the KCl-H2O binary, the liquidus in the NaCl-KCl-H2O ternary, and the solidus in the NaCl-KCl binary to 2 kb pressure, and a summary of experimental data for thermodynamic-PTX analysis of solid-liquid equilibria at elevated P-T conditions

    USGS Publications Warehouse

    Chou, I.-Ming; Sterner, S.M.; Pitzer, Kenneth S.

    1992-01-01

    The sylvite liquidus in the binary system KCl-H2O and the liquidus in the ternary system NaCl-KCl-H2O were determined by using isobaric differential thermal analysis (DTA) cooling scans at pressures up to 2 kbars. Sylvite solubilities along the three-phase curve in the binary system KCl-H2O were obtained by the intersection of sylvite-liquidus isopleths with the three-phase curve in a P-T plot. These solubility data can be represented by the equation Wt.% KCl (??0.2) = 12.19 + 0.1557T - 5.4071 ?? 10-5 T2, where 400 ??? T ??? 770??C. These data are consistent with previous experimental observations. The solidus in the binary system NaCl-KCl was determined by using isobaric DTA heating scans at pressures up to 2 kbars. Using these liquidus and solidus data and other published information, a thermodynamic-PTX analysis of solid-liquid equilibria at high pressures and temperatures for the ternary system has been performed and is presented in an accompanying paper (Part V of this series). However, all experimental liquidus, solidus, and solvus data used in this analysis are summarized in this report (Part IV) and they are compared with the calculated values based on the analysis. ?? 1992.

  5. Fundamentals and applications of self-assembled plasmonic nanoparticles at interfaces.

    PubMed

    Edel, Joshua B; Kornyshev, Alexei A; Kucernak, Anthony R; Urbakh, Michael

    2016-03-21

    This tutorial review will introduce and explore fundamental and applied aspects of electrolytic interfaces incorporating nanoscale building blocks for use in novel applications such as sensors and tunable optics. In order to do this, it is important to understand the principles behind even the simplest of immiscible interfaces such as those of the liquid|liquid and solid|liquid. Qualitatively, the picture is simple however the complexity is easily compounded by the addition of electrolyte, and further compounded by the addition of more complex entities such as nanoparticles. Nevertheless combining all these components surprisingly results in an elegant solution, where the nanoparticles have the ability to self-assemble at the interface with a high level of control. Importantly, this opens up the door to the development of new types of materials with a range of applications which have only recently been exploited. Initially we begin with a description of the fundamentals related to liquid|liquid and solid|liquid interfaces both with and without electrolyte. The discussion then shifts to a description of biasing the interface by the application of an electric field. This is followed by an exploration of nanoparticle assembly and disassembly at the interface by controlling parameters such as ligand composition, charge, pH, and electric field. Finally a description of the state-of-the-art is given in terms of current applications and possible future directions. It is perhaps fair to say that these new frontiers have caused great excitement within the sensing community not only due to the simplicity of the technique but also due to the unprecedented levels of sensitivity and control. PMID:26806599

  6. Developpement d'une plateforme de calcul d'equilibres chimiques complexes et adaptation aux problemes electrochimiques et d'equilibres contraints

    NASA Astrophysics Data System (ADS)

    Neron, Alex

    Avec l'arrivée de l'environnement comme enjeu mondial, le secteur de l'efficacité énergétique prend une place de plus en plus importante pour les entreprises autant au niveau économique que pour l'image de la compagnie. Par le fait même, le domaine des technologies de l'énergie est un créneau de recherche dont les projets en cours se multiplient. D'ailleurs, un des problèmes qui peut survenir fréquemment dans certaines entreprises est d'aller mesurer la composition des matériaux dans des conditions difficiles d'accès. C'est le cas par exemple de l'électrolyse de l'aluminium qui se réalise à des températures très élevées. Pour pallier à ce problème, il faut créer et valider des modèles mathématiques qui vont calculer la composition et les propriétés à l'équilibre du système chimique. Ainsi, l'objectif global du projet de recherche est de développer un outil de calcul d'équilibres chimiques complexes (plusieurs réactions et plusieurs phases) et l'adapter aux problèmes électrochimiques et d'équilibres contraints. Plus spécifiquement, la plateforme de calcul doit tenir compte de la variation de température due à un gain ou une perte en énergie du système. Elle doit aussi considérer la limitation de l'équilibre due à un taux de réaction et enfin, résoudre les problèmes d'équilibres électrochimiques. Pour y parvenir, les propriétés thermodynamiques telles que l'énergie libre de Gibbs, la fugacité et l'activité sont tout d'abord étudiées pour mieux comprendre les interactions moléculaires qui régissent les équilibres chimiques. Ensuite, un bilan énergétique est inséré à la plateforme de calcul, ce qui permet de calculer la température à laquelle le système est le plus stable en fonction d'une température initiale et d'une quantité d'énergie échangée. Puis, une contrainte cinétique est ajoutée au système afin de calculer les équilibres pseudo-stationnaires en évolution dans le temps. De plus, la

  7. Paternité des articles et intérêts concurrents : une analyse des recommandations aux auteurs des journaux traitant de pratique pharmaceutique

    PubMed Central

    Courbon, Ève; Tanguay, Cynthia; Lebel, Denis; Bussières, Jean-François

    2014-01-01

    RÉSUMÉ Contexte : La présence d’auteurs honorifiques et fantômes ainsi que les intérêts concurrents représentent des difficultés bien documentées, liées à la publication d’articles scientifiques. Il existe des lignes directrices encadrant la rédaction et la publication de manuscrits scientifiques, notamment celles de l’International Committee of Medical Journal Editors (ICMJE). Objectifs : L’objectif principal de cette étude descriptive et transversale visait à recenser les instructions portant sur la paternité des articles et les intérêts concurrents provenant des recommandations aux auteurs des journaux traitant de pratique pharmaceutique. L’objectif secondaire visait à déterminer des mesures correctrices pour une paternité des articles plus transparente. Méthode : La recherche a débuté par l’identification des journaux traitant de pratique pharmaceutique. La consultation des instructions aux auteurs des journaux a permis ensuite de recenser les recommandations destinées à éviter les problèmes de paternité des articles et d’intérêts concurrents. Finalement, les membres de l’équipe de recherche se sont consultés afin de définir des mesures correctrices possibles à l’intention des chercheurs. Résultats : Des 232 journaux traitant de pharmacie, 33 ont été définis comme traitant de pratique pharmaceutique. Un total de 24 (73 %) journaux mentionnaient suivre la politique de l’ICMJE, 14 (42 %) demandaient aux auteurs de remplir un formulaire de déclaration d’intérêts concurrents au moment de la soumission de l’article, 17 (52 %) présentaient une définition de la qualité d’auteur et 5 (15 %) demandaient de détailler les contributions de chaque auteur. Une grille de 40 critères a été élaborée pour définir l’attribution du statut d’auteur. Conclusion : Moins de la moitié des journaux demandait aux auteurs de transmettre un formulaire de déclaration des intérêts concurrents au moment de la

  8. Le syndrome d'insensibilité complète aux androgènes: à propos de deux cas et revue de la literature

    PubMed Central

    Lachiri, Boutaina; Hakimi, Ihssane; Boudhas, Adil; Guelzim, Khalid; Kouach, Jaouad; Oukabli, Mohamed; Rahali, Driss Moussaoui; Dehayni, Mohamed

    2015-01-01

    Le syndrome d'insensibilité complète aux androgènes (SICA) est une entité rare qui correspond à la forme complète des pseudohermaphrodismes androgynoïdes. Son incidence est en fait très variable, allant, selon les auteurs de 1/20000 à 1/60000 naissances. Il est caractérisé par la coexistence chez le même sujet d'un caryotype masculin (46 XY), avec des gonades males, et d'une morphologie féminine normale. Les auteurs rapportent deux observations de deux jeunes filles présentant le SICA ayant consulté pour aménorrhée primaire, illustrant les particularités cliniques, anatomopathologiques et biologiques du syndrome avec certaines particularités. PMID:26301004

  9. Ordered BaAl4- Type Variants in the BaAuxSn4-x System: A Unified View on Their Phase Stabilities versus Valence Electron Counts

    SciTech Connect

    Lin, Qisheng; Miller, Gordon J.; Corbett, John D.

    2014-05-28

    Three ordered structures of the tetragonal BaAl4 type were identified in the Ba–Au–Sn system, from which a unified view of the interplay between the valence electron counts (VECs) and phase stabilities of these three types of derivatives can be developed. The BaNiSn3 (I4mm), ThCr2Si2 (I4/mmm), and CaBe2Ge2 (P4/nmm) type BaAuxSn4–x phases occurred respectively at x = 0.78(1)–1, 1.38(1)–1.47(1), and 1.52(1)–2.17(1), consistent with theoretical atomic “coloring” analyses that reveal an optimal VEC of 14 for the ThCr2Si2 type but larger and smaller values respectively for the BaNiSn3- and CaBe2Ge2-type structures.

  10. J. M. Despréaux' lichens from the Canary Islands and West Africa: an account of a 19th century collection found in an English archive.

    PubMed

    Aguirre-Hudson, Begoña; Whitworth, Isabella; Spooner, Brian M

    2011-01-01

    This is an historical and descriptive account of 28 herbarium specimens, 27 lichens and an alga, found in the archives of Charles Chalcraft, a descendant of the Bedford family, who were dye manufacturers in Leeds, England, in the 19th century. The lichens comprise 13 different morphotypes collected in the Canary Islands and West Africa by the French botanist J. M. Despréaux between 1833 and 1839. The collections include samples of "Roccella fuciformis", "R. phycopsis" and "R. tinctoria" (including the fertile morphotype "R. canariensis"), "Ramalina crispatula" and "R. cupularis", two distinct morphotypes of "Sticta", "S. canariensis" and "S. dufouri", "Physconia enteroxantha", "Pseudevernia furfuracea var. ceratea" and "Pseudocyphellaria argyracea". The herbarium also includes authentic material of "Parmotrema tinctorum" and a probable syntype of "Seirophora scorigena". Most of these species are known as a source of the purple dye orchil, which was used to dye silk and wool. PMID:21941694

  11. Conserved and unique features of the homeologous maize Aux/IAA proteins ROOTLESS WITH UNDETECTABLE MERISTEM 1 and RUM1-like 1

    PubMed Central

    Zhang, Yanxiang; Marcon, Caroline; Tai, Huanhuan; von Behrens, Inga; Ludwig, Yvonne; Hey, Stefan; Berendzen, Kenneth W.; Hochholdinger, Frank

    2016-01-01

    The maize (Zea mays L.) Aux/IAA protein RUM1 (ROOTLESS WITH UNDETECTABLE MERISTEM 1) is a key regulator of lateral and seminal root formation. An ancient maize genome duplication resulted in the emergence of its homeolog rum1-like1 (rul1), which displays 92% amino acid sequence identity with RUM1. Both, RUL1 and RUM1 exhibit the canonical four domain structure of Aux/IAA proteins. Moreover, both are localized to the nucleus, are instable and have similar short half-lives of ~23min. Moreover, RUL1 and RUM1 can be stabilized by specific mutations in the five amino acid degron sequence of domain II. In addition, proteins encoded by both genes interact in vivo with auxin response factors (ARFs) such as ZmARF25 and ZmARF34 in protoplasts. Although it was demonstrated that RUL1 and RUM1 can homo and heterodimerize in vivo, rul1 expression is independent of rum1. Moreover, on average rul1 expression is ~84-fold higher than rum1 in the 12 tested tissues and developmental stages, although the relative expression levels in different root tissues are very similar. While RUM1 and RUL1 display conserved biochemical properties, yeast-two-hybrid in combination with BiFC experiments identified a RUM1-associated protein 1 (RAP1) that specifically interacts with RUM1 but not with RUL1. This suggests that RUM1 and RUL1 are at least in part interwoven into different molecular networks. PMID:26672614

  12. Expression profile of PIN, AUX/LAX and PGP auxin transporter gene families in Sorghum bicolor under phytohormone and abiotic stress.

    PubMed

    Shen, ChenJia; Bai, YouHuang; Wang, SuiKang; Zhang, SaiNa; Wu, YunRong; Chen, Ming; Jiang, DeAn; Qi, YanHua

    2010-07-01

    Auxin is transported by the influx carriers auxin resistant 1/like aux1 (AUX/LAX), and the efflux carriers pin-formed (PIN) and P-glycoprotein (PGP), which play a major role in polar auxin transport. Several auxin transporter genes have been characterized in dicotyledonous Arabidopsis, but most are unknown in monocotyledons, especially in sorghum. Here, we analyze the chromosome distribution, gene duplication and intron/exon of SbPIN, SbLAX and SbPGP gene families, and examine their phylogenic relationships in Arabidopsis, rice and sorghum. Real-time PCR analysis demonstrated that most of these genes were differently expressed in the organs of sorghum. SbPIN3 and SbPIN9 were highly expressed in flowers, SbLAX2 and SbPGP17 were mainly expressed in stems, and SbPGP7 was strongly expressed in roots. This suggests that individual genes might participate in specific organ development. The expression profiles of these gene families were analyzed after treatment with: (a) the phytohormones indole-3-acetic acid and brassinosteroid; (b) the polar auxin transport inhibitors 1-naphthoxyacetic acids, 1-naphthylphthalamic acid and 2,3,5-triiodobenzoic acid; and (c) abscissic acid and the abiotic stresses of high salinity and drought. Most of the auxin transporter genes were strongly induced by indole-3-acetic acid and brassinosteroid, providing new evidence for the synergism of these phytohormones. Interestingly, most genes showed similar trends in expression under polar auxin transport inhibitors and each also responded to abscissic acid, salt and drought. This study provides new insights into the auxin transporters of sorghum. PMID:20528920

  13. Conserved and unique features of the homeologous maize Aux/IAA proteins ROOTLESS WITH UNDETECTABLE MERISTEM 1 and RUM1-like 1.

    PubMed

    Zhang, Yanxiang; Marcon, Caroline; Tai, Huanhuan; von Behrens, Inga; Ludwig, Yvonne; Hey, Stefan; Berendzen, Kenneth W; Hochholdinger, Frank

    2016-02-01

    The maize (Zea mays L.) Aux/IAA protein RUM1 (ROOTLESS WITH UNDETECTABLE MERISTEM 1) is a key regulator of lateral and seminal root formation. An ancient maize genome duplication resulted in the emergence of its homeolog rum1-like1 (rul1), which displays 92% amino acid sequence identity with RUM1. Both, RUL1 and RUM1 exhibit the canonical four domain structure of Aux/IAA proteins. Moreover, both are localized to the nucleus, are instable and have similar short half-lives of ~23min. Moreover, RUL1 and RUM1 can be stabilized by specific mutations in the five amino acid degron sequence of domain II. In addition, proteins encoded by both genes interact in vivo with auxin response factors (ARFs) such as ZmARF25 and ZmARF34 in protoplasts. Although it was demonstrated that RUL1 and RUM1 can homo and heterodimerize in vivo, rul1 expression is independent of rum1. Moreover, on average rul1 expression is ~84-fold higher than rum1 in the 12 tested tissues and developmental stages, although the relative expression levels in different root tissues are very similar. While RUM1 and RUL1 display conserved biochemical properties, yeast-two-hybrid in combination with BiFC experiments identified a RUM1-associated protein 1 (RAP1) that specifically interacts with RUM1 but not with RUL1. This suggests that RUM1 and RUL1 are at least in part interwoven into different molecular networks. PMID:26672614

  14. Elevated Seismic Activity Beneath the Slumbering Morne aux Diables Volcano, Northern Dominica and the Monitoring Role of the Seismic Research Centre

    NASA Astrophysics Data System (ADS)

    Watts, R. B.; Robertson, R. E.; Abraham, W.; Cole, P.; de Roche, T.; Edwards, S.; Higgins, M.; Johnson, M.; Joseph, E. P.; Latchman, J.; Lynch, L.; Nath, N.; Ramsingh, C.; Stewart, R. C.

    2012-12-01

    Since June 2009, periods of elevated seismic activity have been experienced around the flanks of Morne Aux Diables Volcano in northern Dominica. This long-dormant volcano is a complex of 7 andesitic lava domes with a central depression where a cold soufrière is evident. Prior to this activity, seismicity was very quiet except for a short period in 2000 and an intense short-lived swarm in April 2003. The most recent earthquake activity has been regularly felt by residents in villages on all flanks of the complex. In Dec 09/Jan10, scientists from the Seismic Research Centre (SRC), based in Trinidad & Tobago, in collaboration with staff of the Office of Disaster Management (ODM) and Dominica Public Seismic Network (DPSN) improved the monitoring capacity around this volcano from 1 to 7 seismic stations. Earthquakes are determined to be volcano-tectonic in nature and located at shallow depths (<4 km) beneath the central depression. Additionally, in Jan/Feb 10 geothermal sampling was undertaken and 2 permanent GPS sites were deployed. Public information leaflets prepared by SRC scientists using a "Question & Answer" format have been distributed to concerned citizens whilst many public meetings were carried out by ODM staff. Field investigations indicate that the previous Late Pleistocene activity of Morne Aux Diables switched from Pelèan dome growth and gravitational collapse to more explosive pumice-falls and associated ignimbrites, both styles forming extensive pyroclastic fans around the central complex. The town of Portsmouth is located on one of these fans ~5 km southwest of the central depression. Sporadic, short bursts of seismic activity continue at the time of writing.

  15. Subnanometer-Resolution Frequency Modulation Atomic Force Microscopy in Liquid for Biological Applications

    NASA Astrophysics Data System (ADS)

    Fukuma, Takeshi

    2009-08-01

    The spatial resolution and force sensitivity of frequency modulation atomic force microscopy (FM-AFM) in liquid have been dramatically improved in the last a few years. It is now possible to image individual atoms and molecules at a solid/liquid interface with a subnanometer-scale resolution and a piconewton-order loading force. This capability enabled the direct visualization of hydration layers and mobile ions on a lipid bilayer and β-strands constituting an amyloid fibril. These striking results highlighted the significant potential of FM-AFM in biological research. Here, I summarize the technological innovation that brought about this progress and review biological applications of FM-AFM in liquid.

  16. Application of PTR-MS for measuring odorant emissions from soil application of manure slurry.

    PubMed

    Feilberg, Anders; Bildsoe, Pernille; Nyord, Tavs

    2015-01-01

    Odorous volatile organic compounds (VOC) and hydrogen sulfide (H2S) are emitted together with ammonia (NH3) from manure slurry applied as a fertilizer, but little is known about the composition and temporal variation of the emissions. In this work, a laboratory method based on dynamic flux chambers packed with soil has been used to measure emissions from untreated pig slurry and slurry treated by solid-liquid separation and ozonation. Proton-transfer-reaction mass spectrometry (PTR-MS) was used to provide time resolved data for a range of VOC, NH3 and H2S. VOC included organic sulfur compounds, carboxylic acids, phenols, indoles, alcohols, ketones and aldehydes. H2S emission was remarkably observed to take place only in the initial minutes after slurry application, which is explained by its high partitioning into the air phase. Long-term odor effects are therefore assessed to be mainly due to other volatile compounds with low odor threshold values, such as 4-methylphenol. PTR-MS signal assignment was verified by comparison to a photo-acoustic analyzer (NH3) and to thermal desorption GC/MS (VOC). Due to initial rapid changes in odorant emissions and low concentrations of odorants, PTR-MS is assessed to be a very useful method for assessing odor following field application of slurry. The effects of treatments on odorant emissions are discussed. PMID:25585103

  17. Application of PTR-MS for Measuring Odorant Emissions from Soil Application of Manure Slurry

    PubMed Central

    Feilberg, Anders; Bildsoe, Pernille; Nyord, Tavs

    2015-01-01

    Odorous volatile organic compounds (VOC) and hydrogen sulfide (H2S) are emitted together with ammonia (NH3) from manure slurry applied as a fertilizer, but little is known about the composition and temporal variation of the emissions. In this work, a laboratory method based on dynamic flux chambers packed with soil has been used to measure emissions from untreated pig slurry and slurry treated by solid-liquid separation and ozonation. Proton-transfer-reaction mass spectrometry (PTR-MS) was used to provide time resolved data for a range of VOC, NH3 and H2S. VOC included organic sulfur compounds, carboxylic acids, phenols, indoles, alcohols, ketones and aldehydes. H2S emission was remarkably observed to take place only in the initial minutes after slurry application, which is explained by its high partitioning into the air phase. Long-term odor effects are therefore assessed to be mainly due to other volatile compounds with low odor threshold values, such as 4-methylphenol. PTR-MS signal assignment was verified by comparison to a photo-acoustic analyzer (NH3) and to thermal desorption GC/MS (VOC). Due to initial rapid changes in odorant emissions and low concentrations of odorants, PTR-MS is assessed to be a very useful method for assessing odor following field application of slurry. The effects of treatments on odorant emissions are discussed. PMID:25585103

  18. Recent advances in vacuum sciences and applications

    NASA Astrophysics Data System (ADS)

    Mozetič, M.; Ostrikov, K.; Ruzic, D. N.; Curreli, D.; Cvelbar, U.; Vesel, A.; Primc, G.; Leisch, M.; Jousten, K.; Malyshev, O. B.; Hendricks, J. H.; Kövér, L.; Tagliaferro, A.; Conde, O.; Silvestre, A. J.; Giapintzakis, J.; Buljan, M.; Radić, N.; Dražić, G.; Bernstorff, S.; Biederman, H.; Kylián, O.; Hanuš, J.; Miloševič, S.; Galtayries, A.; Dietrich, P.; Unger, W.; Lehocky, M.; Sedlarik, V.; Stana-Kleinschek, K.; Drmota-Petrič, A.; Pireaux, J. J.; Rogers, J. W.; Anderle, M.

    2014-04-01

    Recent advances in vacuum sciences and applications are reviewed. Novel optical interferometer cavity devices enable pressure measurements with ppm accuracy. The innovative dynamic vacuum standard allows for pressure measurements with temporal resolution of 2 ms. Vacuum issues in the construction of huge ultra-high vacuum devices worldwide are reviewed. Recent advances in surface science and thin films include new phenomena observed in electron transport near solid surfaces as well as novel results on the properties of carbon nanomaterials. Precise techniques for surface and thin-film characterization have been applied in the conservation technology of cultural heritage objects and recent advances in the characterization of biointerfaces are presented. The combination of various vacuum and atmospheric-pressure techniques enables an insight into the complex phenomena of protein and other biomolecule conformations on solid surfaces. Studying these phenomena at solid-liquid interfaces is regarded as the main issue in the development of alternative techniques for drug delivery, tissue engineering and thus the development of innovative techniques for curing cancer and cardiovascular diseases. A review on recent advances in plasma medicine is presented as well as novel hypotheses on cell apoptosis upon treatment with gaseous plasma. Finally, recent advances in plasma nanoscience are illustrated with several examples and a roadmap for future activities is presented.

  19. Cartographie de parametres forestiers par fusion evidentielle de donnees geospatiales multi-sources: Application aux peuplements forestiers en regeneration et feuillus matures du Sud du Quebec

    NASA Astrophysics Data System (ADS)

    Mora, Brice

    2009-10-01

    Foresters are faced with difficulties to obtain sub-polygon information with the mapping methods available nowadays. The main objective of this work consisted in the development of new methods able to improve the map accuracy of regenerating forest stands and mature forest stands in the South of Quebec, Canada. The Dempster-Shafer Theory (DST) and the Dezert-Smarandache Theory (DSmT) showed their ability to integrate multiple heterogenous data sources to go further than the classical classification procedures like the maximum likelihood or the spectral unmixing, in terms of map accuracy. Improvement on the ability to map regenerating stands, passed from 82.7% with the maximum likelihood method to 91.1% with the Free DSm model with a total transfer of the mass of the "Union" class to the "Intersection" class (+ 8.4%). For the mature stands, the improvement passed from 63.8% with the K nearest neighbour to 79.5% with the DST according to a classical belief structuration and the hybrid decision rule for which the conflict threshold was fixed at 10% (+ 15.7%). Our results with DST and a bayesian belief structuration showed the difficulty to model the uncertainty in the fusion process. This is probably due to the lack of scientific knowledge about the influence of the biophysical and climatic parameters on the mapped forest stands and to the necessity to model specifically the uncertainty for each source. Our work showed concrete improvement when mapping forest stands with DST which is encouraging to continue explorating the fundamental principle of the proposed hybrid decision rule. This means a particular focus on the difference between the fused masses of each potential class after the fusion, to choose the best hypothesis. Keywords. forest mapping, Quebec, deciduous stands, regenerating stands, mature stands, data fusion, Dempster-Shafer Theory, Dezert-Smarandache Theory, hybrid decision rule

  20. Aspects épidémiologiques des accidents vasculaires cérébraux (AVC) aux urgences de l'institut de cardiologie d'Abidjan (ICA)

    PubMed Central

    N'goran, Yves N'da Kouakou; Traore, Fatou; Tano, Micesse; Kramoh, Kouadio Euloge; Kakou, Jean-Baptiste Anzouan; Konin, Christophe; Kakou, Maurice Guikahue

    2015-01-01

    Introduction L'objectif de notre étude était de décrire les caractéristiques sociodémographiques et les Facteurs de Risque cardio-Vasculaires (FRV) des patients admis pour accidents vasculaires cérébraux (AVC) dans un service autre que celui de la neurologie. Méthodes Étude transversale rétrospective sur une période de 2 ans (janv. 2010 et déc. 2011), réalisée aux urgences de l'institut de cardiologie d'Abidjan. Résultats Il s'agissait de 176 adultes avec un âge moyen de 60 ans, une prédominance féminine. Les facteurs de risque majeurs retrouvés étaient l'hypertension artérielle dans 86,4% des cas, le diabète dans 11,4% des cas, le tabagisme dans 2,2% des cas. Les motifs de consultation étaient la perte de connaissance dans 36,4% des cas, l'hémiplégie dans 31,8% des cas, les céphalées dans 17,4% des cas, les vertiges dans 10,9% et les palpitations dans 2,2% des cas. La tension artérielle systolique moyenne était à 174 mmHg, la tension artérielle diastolique moyenne était à 105 mmHg et la pression pulsée moyenne était à 70 mmHg. Les AVC étaient associés à une arythmie complète par fibrillation auriculaire dans 11,4% des cas. Les AVC ischémiques représentaient 84,1%. L’évolution aux urgences a été marquée par un décès dans 17% (30) des cas. Conclusion Les AVC constituent un problème majeur de santé publique. Malgré sa prédominance féminine, ils (AVC) touchaient 44% des hommes dans notre étude lorsqu'on sait qu'en Afrique l'activité sociale repose sur les hommes. Ils restent une pathologie grave par la forte létalité. PMID:26327997

  1. Low-temperature thermoelectric, galvanomagnetic, and thermodynamic properties of the type-I clathrate Ba8AuxSi46-x

    NASA Astrophysics Data System (ADS)

    Aydemir, U.; Candolfi, C.; Ormeci, A.; Oztan, Y.; Baitinger, M.; Oeschler, N.; Steglich, F.; Grin, Yu.

    2011-11-01

    Polycrystalline samples of the clathrate Ba8AuxSi46-x were synthesized for 0.2 ⩽ x ⩽ 10. The homogeneity range of the type-I clathrate phase was determined to be 3.63 ⩽ x ⩽ 6.10 after annealing at 900 °C, while a lower Au concentration (x ≈ 2.2) was obtained by steel-quenching. Quasisingle phase materials were obtained for 4.10 ⩽ x ⩽ 6.10. In this composition range, thermoelectric properties, including electrical resistivity, thermopower, and thermal conductivity, were investigated between 2 and 350 K. These experiments were complemented by low-temperature specific heat and Hall-effect measurements (2-300 K). First-principles calculations were carried out to determine the evolution of the electronic structure as a function of x. Both theoretical and experimental results evidence a progressive evolution, with the Au content, from a metallic-like behavior towards a highly doped semiconducting state which develops around x = 5.43. At this concentration, a crossover from n- to p-type conduction occurs, suggesting that the present system satisfies the Zintl-Klemm concept, which predicts a transition at x = 5.33. This crossover is traced by Hall-effect data indicating a dominant electronlike response for x ⩽ 5.43, which turns into a holelike signal at higher x values. Analysis of the data based on a single-parabolic-band model under the assumption of a single scattering mechanism of the charge carriers proved to adequately describe the transport properties in the compositional range investigated. Interestingly, the temperature dependence of the lattice thermal conductivity is strongly influenced by the Au concentration: the typical behavior of crystalline insulators in the n-type compounds evolves into a glasslike dependence in the p-type samples. The series Ba8AuxSi46-x thus provides an excellent testing ground for the interplay between crystal structure, electronic properties, and lattice thermal conductivity in type-I clathrates.

  2. DET/MPS - THE GSFC ENERGY BALANCE PROGRAM, DIRECT ENERGY TRANSFER/MULTIMISSION SPACECRAFT MODULAR POWER SYSTEM (MACINTOSH A/UX VERSION)

    NASA Technical Reports Server (NTRS)

    Jagielski, J. M.

    1994-01-01

    The DET/MPS programs model and simulate the Direct Energy Transfer and Multimission Spacecraft Modular Power System in order to aid both in design and in analysis of orbital energy balance. Typically, the DET power system has the solar array directly to the spacecraft bus, and the central building block of MPS is the Standard Power Regulator Unit. DET/MPS allows a minute-by-minute simulation of the power system's performance as it responds to various orbital parameters, focusing its output on solar array output and battery characteristics. While this package is limited in terms of orbital mechanics, it is sufficient to calculate eclipse and solar array data for circular or non-circular orbits. DET/MPS can be adjusted to run one or sequential orbits up to about one week, simulated time. These programs have been used on a variety of Goddard Space Flight Center spacecraft projects. DET/MPS is written in FORTRAN 77 with some VAX-type extensions. Any FORTRAN 77 compiler that includes VAX extensions should be able to compile and run the program with little or no modifications. The compiler must at least support free-form (or tab-delineated) source format and 'do do-while end-do' control structures. DET/MPS is available for three platforms: GSC-13374, for DEC VAX series computers running VMS, is available in DEC VAX Backup format on a 9-track 1600 BPI tape (standard distribution) or TK50 tape cartridge; GSC-13443, for UNIX-based computers, is available on a .25 inch streaming magnetic tape cartridge in UNIX tar format; and GSC-13444, for Macintosh computers running AU/X with either the NKR FORTRAN or AbSoft MacFORTRAN II compilers, is available on a 3.5 inch 800K Macintosh format diskette. Source code and test data are supplied. The UNIX version of DET requires 90K of main memory for execution. DET/MPS was developed in 1990. A/UX and Macintosh are registered trademarks of Apple Computer, Inc. VMS, DEC VAX and TK50 are trademarks of Digital Equipment Corporation. UNIX is a

  3. Limits of applicability of the “diffusion-controlled product growth” kinetic approach to modeling SHS

    NASA Astrophysics Data System (ADS)

    Khina, B. B.; Formanek, B.; Solpan, I.

    2005-01-01

    In modeling SHS in condensed systems, it is typically considered that a solid and a liquid reactant (a molten metal) are separated by a solid product interlayer, and diffusion in this layer is the rate-controlling stage (a “solid-solid-liquid mechanism”). However, in most cases modeling is performed not with real diffusion data (activation energy E and preexponent D0) for the product phase but with fitting parameters which are chosen to match the calculated and measured thermal characteristics of the SHS wave. In this work, a system of kinetic, thermodynamic and structural estimates is developed for evaluating the validity of this approach for particular SHS systems/conditions using available experimental data on both diffusion in the product phase and characteristics of the SHS wave. A classical Ti-C system is chosen as an example. Change in geometry of a unit reaction cell due to melting and spreading of the metallic reactant is taken into account, and different situations arising within this concept are analyzed. It is demonstrated that the “diffusion-controlled growth” kinetics is not applicable to SHS of interstitial compounds in the wave propagation regime because it cannot provide sufficient heat release for sustaining SHS and the final product structure will disagree with experimental data known in literature. As an alternative, a “solid-liquid mechanism” of phase formation during SHS is grounded, which implies a direct contact of a metallic melt with a solid reactant. A micromechanistic criterion for a changeover of these interaction routes is obtained, which is important for SHS in the thermal explosion mode.

  4. Application of electro acoustics for dewatering pharmaceutical sludge

    SciTech Connect

    Golla, P.S.; Johnson, H.W. ) Senthilnathan, P.R. )

    1992-02-01

    Application of electro acoustic principles for dewatering has been developed by Battelle Institute. The Department of Energy, Battelle Institute, and Ashbrook-Simon-Hartley, have jointly developed an Electro Acoustic Dewatering press (EAD press). The EAD press applies a combination of mechanical pressure, electrical current and ultrasonics. This press is utilized after conventional dewatering devices and can remove up to 50% water from filtered sludge cake at a fraction of the cost incurred in existing thermal drying devices. The dominant mechanism of sludge dewatering by EAD press is electro-osmosis due to the application of a direct current field. Electro-osmosis is caused by an electrical double layer of oppositely charged ions formed at the solid liquid interface, which is characterized by zeta potential. The ultrasonic fields help electro-osmosis by consolidation of the filter cake and by release of inaccessible liquid. The EAD press has been tested successfully on a variety of materials including apple pomace, corn gluten, sewage sludge, and coal fines. A three week long full scale trial was conducted successfully at a pharmaceutical industry to determine the application of this technology for dewatering waste activated sludge.

  5. Transposition des gros vaisseaux associée aux communications interventriculaire et interauriculaire: à propos d'un cas et revue de la littérature

    PubMed Central

    Mutombo, Augustin Mulangu; Mukuku, Olivier; Lubala, Toni Kasole; Kabuya, Maguy Sangaji; Ilunga, Paul Makinko; Bugeme, Marcellin; Luboya, Oscar Numbi

    2013-01-01

    Nous rapportons une observation d'un nourrisson de 5 mois présentant une transposition des gros vaisseaux associée aux communications interventriculaire et interauriculaire. Il est né à terme sans aucun facteur de risque retrouvé dans les antécédents maternels. Le diagnostic est posé, grâce à une échocardiographie, à 5 mois après sa naissance lors de la survenue d'une cyanose et d'un malaise anoxique. Une prise en charge symptomatique a permis de stabiliser l’état du patient mais suite à l'absence d'un traitement chirurgical, il est décédé à domicile 3 semaines après sa sortie de l'hôpital. Dans les pays en développement, le diagnostic de la transposition des gros vaisseaux est souvent fait en période postnatale et son pronostic reste fatal par manque des centres médico-chirurgicaux spécialisés. PMID:24009800

  6. Ammonium inhibition of Arabidopsis root growth can be reversed by potassium and by auxin resistance mutations aux1, axr1, and axr2.

    PubMed Central

    Cao, Y; Glass, A D; Crawford, N M

    1993-01-01

    A novel effect of ammonium ions on root growth was investigated to understand how environmental signals affect organ development. Ammonium ions (3-12 mM) were found to dramatically inhibit Arabidopsis thaliana seedling root growth in the absence of potassium even if nitrate was present. This inhibition could be reversed by including in the growth medium low levels (20-100 microM) of potassium or alkali ions Rb+ and Cs+ but not alkali ions Na+ and Li+. The protective effect of low concentrations of potassium is not due to an inhibition of ammonium uptake. Ammonium inhibition is reversible, because root growth was restored in ammonium-treated seedlings if they were subsequently transferred to medium containing potassium. It is known that plant hormones can inhibit root growth. We found that mutants of Arabidopsis resistant to high levels of auxin and other hormones (aux1, axr1, and axr2) are also resistant to the ammonium inhibition and produce roots in the absence of potassium. Thus, the mechanisms that mediate the ammonium inhibition of root development are linked to hormone metabolic or signaling pathways. These findings have important implications for understanding how environmental signals, especially mineral nutrients, affect plant root development. PMID:8278539

  7. Effects of cattle-slurry treatment by acidification and separation on nitrogen dynamics and global warming potential after surface application to an acidic soil.

    PubMed

    Fangueiro, David; Pereira, José; Bichana, André; Surgy, Sónia; Cabral, Fernanda; Coutinho, João

    2015-10-01

    Cattle-slurry (liquid manure) application to soil is a common practice to provide nutrients and organic matter for crop growth but it also strongly impacts the environment. The objective of the present study was to assess the efficiency of cattle-slurry treatment by solid-liquid separation and/or acidification on nitrogen dynamics and global warming potential (GWP) following application to an acidic soil. An aerobic laboratory incubation was performed over 92 days with a Dystric Cambisol amended with raw cattle-slurry or separated liquid fraction (LF) treated or not by acidification to pH 5.5 by addition of sulphuric acid. Soil mineral N contents and NH3, N2O, CH4 and CO2 emissions were measured. Results obtained suggest that the acidification of raw cattle-slurry reduced significantly NH3 emissions (-88%) but also the GWP (-28%) while increased the N availability relative to raw cattle-slurry (15% of organic N applied mineralised against negative mineralisation in raw slurry). However, similar NH3 emissions and GWP were observed in acidified LF and non-acidified LF treatments. On the other hand, soil application of acidified cattle-slurry rather than non-acidified LF should be preferred attending the lower costs associated to acidification compared to solid-liquid separation. It can then be concluded that cattle-slurry acidification is a solution to minimise NH3 emissions from amended soil and an efficient strategy to decrease the GWP associated with slurry application to soil. Furthermore, the more intense N mineralisation observed with acidified slurry should lead to a higher amount of plant available N and consequently to higher crop yields. PMID:26217884

  8. Administration d’anti-inflammatoires non stéroïdiens aux enfants ayant des antécédents de sibilance

    PubMed Central

    Sih, Kendra; Goldman, Ran D.

    2016-01-01

    Résumé Question Un enfant qui fréquente ma clinique s’est récemment fait une entorse à la cheville et il éprouve de la douleur et de la difficulté à supporter son poids sur la jambe affectée. Sa mère lui donne de l’acétaminophène parce qu’on lui a dit de ne jamais utiliser d’anti-inflammatoires non stéroïdiens (AINS) en raison de son asthme contrôlé par pharmacologie. L’asthme chez un enfant est-il une contre-indication à l’administration d’AINS? La maladie respiratoire exacerbée par les AINS existe-t-elle comme entité réelle? Réponse Les AINS sont des médicaments analgésiques et antipyrétiques efficaces. La maladie respiratoire exacerbée par des AINS a été décrite chez des adultes ayant certains facteurs de prédisposition, mais n’a pas été clairement identifiée chez un grand nombre d’enfants. Les AINS peuvent donc être recommandés aux enfants ayant une sibilance connue qui n’ont pas d’antécédents de maladie respiratoire déclenchée par des AINS. PMID:27521406

  9. Pulsed laser-induced evaporation of liquids and its applications

    NASA Astrophysics Data System (ADS)

    Kim, Dongsik

    The interaction of laser irradiation with materials is very important in a variety of laser-based manufacturing processes and scientific studies. Particularly, the interaction of a short laser pulse with absorbing liquids or solid materials in contact with liquid is central to a number of applications, including laser cleaning of microcontaminants, pulsed laser deposition of thin film materials, laser tissue removal, and laser surface texturing. In this dissertation, experimental and theoretical works on the following topics are summarized: (1) physical mechanisms of pulsed laser induced ablation of absorbing liquids at laser fluence below the plasma ignition threshold, (2) analysis of rapid vaporization at the absorbing solid/transparent liquid interface, (3) laser cleaning of surface contaminates. Concerning the first topic, the near-threshold ablation process at low laser fluences and the high power explosive vaporization process accompanying subsequent ablation plume dynamics are elucidated. Acoustic-wave detection by a piezoelectric pressure transducer, visualization by laser flash photography, and optical reflection/transmission measurements are carried out for the in-situ diagnosis of the process. Quantification of the acoustic-field generation and detection of the bubble-nucleation dynamics in the rapid vaporization at the solid liquid interface are performed by photoacoustic beam deflection technique and optical interferometry, respectively. Finally, experiments are carried out for the development of a practical laser cleaning tool and the analysis of the contaminant-removal mechanism. The results show that the near-threshold ablation by a short laser pulse is initiated by the tensile component of the thermoelastic stress without significant increase of liquid temperature at low laser fluences. On the other hand, if the heating rate is rapid enough to achieve high degree of superheating of the liquid, explosive vaporization takes place due to the abrupt

  10. A study of the applicability of nucleation theory to quasi-thermodynamic transitions of second and higher Ehrenfest-order, supplement 3

    NASA Technical Reports Server (NTRS)

    Barker, R. E., Jr.

    1986-01-01

    The work includes an investigation of the applicability of the nucleation theory to second and higher order thermodynamic transitions in the Ehrenfest sense, and a number of significant conclusions relevant to first order transitions, as well. The underlying theoretical method consisted of expanding the Gibbs' free energy in a Maclarin or Taylor series and then using fundamental thermodynamic determinable quantities, and interpreting the results. Work was performed on the existence and interpretation of an interfacial energy between phases in a second order transition in addition to an investigation of the solid-liquid interfacial energy for various polymers. Extensive considerations were devoted to various aspects of a particular polymer, polyvinylidene fluoride (PVDF or PVF2), including an experimetal investigation of the effects of an applied electric field on the morphology of melt crystallization and on the nucleation and growth of polarized domains.

  11. RE(AuAl2)nAl2(AuxSi1-x)2: a new homologous series of quaternary intermetallics grown from aluminum flux.

    PubMed

    Latturner, Susan E; Kanatzidis, Mercouri G

    2008-03-17

    The combination of early rare earth metals (La- to Gd and Yb), gold, and silicon in molten aluminum results in the formation of intermetallic compounds with four related structures, forming a new homologous series: RE[AuAl2]nAl2(AuxSi(1-x))2, with x approximately 0.5 for most of the compound and n = 0, 1, 2, and 3. Because of the highly reducing nature of the Al flux, rare earth oxides instead of metals can also be used in these reactions. These compounds grow as large plate-like crystals and have tetragonal structure types that can be viewed as intergrowths of the BaAl4 structure and antifluorite-type AuAl2 layers. REAuAl2Si materials form with the BaAl4 structure type in space group I4/mmm (cell parameters for the La analogue are a = 4.322(2) A, c = 10.750(4) A, and Z = 2). REAu2Al4Si forms in a new ordered superstructure of the KCu4S3 structure type, with space group P4/nmm and cell parameters of the La analogue of a = 6.0973(6) A, c = 8.206(1) A, and Z = 2. REAu3Al6Si forms in a new I4/mmm symmetry structure type with cell parameters of a = 4.2733(7) A, c = 22.582(5) A, and Z = 2 for RE = Eu. The end member of the series, REAu4Al8Si, forms in space group P4/mmm with cell parameters for the Yb analogue of a = 4.2294(4) A, c = 14.422(2) A, and Z = 1. New intergrowth structures containing two different kinds of AuAl2 layers were also observed. The magnetic behavior of all these compounds is derived from the RE ions. Comparison of the susceptibility data for the europium compounds indicates a switch from 3-D magnetic interactions to 2-D interactions as the size of the AuAl2 layer increases. The Yb ions in YbAu(2.91)Al(6)Si(1.09) and YbAu(3.86)Al(8)Si(1.14) are divalent at high temperatures. PMID:18198865

  12. Advanced in situ Spectroscopic Techniques And Their Applications In Environmental Biogeochemistry: Introduction To The Special Section

    EPA Science Inventory

    Understanding the molecular-scale complexities and interplay of chemical and biological processes of contaminants at solid, liquid, and gas interfaces is a fundamental and crucial element to enhance our understanding of anthropogenic environmental impacts. The ability to describ...

  13. High-power laser applications in Nippon Steel Corporation

    NASA Astrophysics Data System (ADS)

    Minamida, Katsuhiro

    2000-02-01

    The laser, which was invented in 1960, has been developed using various substances of solids, liquids, gases and semiconductors as laser active media. Applications of laser utilizing the coherent properties of laser light and the high power density light abound in many industries and in heavy industries respectively. The full-scale use of lasers in the steel industry began nearly 23 years ago with their applications as controllable light sources. Its contribution to the increase in efficiency and quality of the steel making process has been important and brought us the saving of the energy, the resource and the labor. Laser applications in the steel making process generally require high input energy, so it is essential to consider the interaction between the laser beam and the irradiated material. In particular, the reflectivity of the laser beam on the surface of material and the quantity of the laser-induced plasma are critical parameters for high efficient processes with low energy losses. We have developed plenty of new laser systems for the steel making process with their considerations in mind. A review of the following high-power-laser applications is given in the present paper: (1) Use of plasma as a secondary heat source in CO2 laser welding for connecting steel sheets of various grades. (2) Laser-assisted electric resistance welding of pipes. (3) New type all-laser-welded honeycomb panels for high-speed transport. (4) Laser flying welder for continuous hot rolling mill using two 45 kW CO2 lasers.

  14. Spatially controlled electro-stimulated DNA adsorption and desorption for biochip applications.

    PubMed

    Hook, Andrew L; Thissen, Helmut; Hayes, Jason P; Voelcker, Nicolas H

    2006-05-15

    The manipulation of biomolecules at solid/liquid interfaces is important for the enhanced performance of a number of biomedical devices, including biochips. This study focuses on the spatial control of surface interactions of DNA as well as the electro-stimulated adsorption and desorption of DNA by appropriate surface modification of highly doped p-type silicon. Surface modification by plasma polymerisation of allylamine resulted in a surface that supported DNA adsorption and sustained cell attachment. Subsequent high-density grafting of poly(ethylene oxide) formed a low fouling layer resistant to biomolecule adsorption and cell attachment. Spatially controlled excimer laser ablation of the surface produced patterns of re-exposed plasma polymer with high-resolution. On patterned surfaces, preferential electro-stimulated adsorption of DNA to the allylamine plasma polymer surface and subsequent desorption by the application of a negative bias was observed. Furthermore, the concept presented here was investigated for use in transfection chips. Cell culture experiments with human embryonic kidney cells, using the expression of green fluorescent protein as a reporter, demonstrated efficient and controlled transfection of cells. Electro-stimulated desorption of DNA was shown to yield significantly enhanced solid phase transfection efficiencies to values of up to 30%. The ability to spatially control DNA adsorption combined with the ability to control the binding and release of DNA by application of a controlled voltage enables an advanced level of control over DNA bioactivity on solid substrates and lends itself to biochip applications. PMID:16303297

  15. Thermal modeling with solid/liquid phase change of the thermal energy storage experiment

    NASA Technical Reports Server (NTRS)

    Skarda, J. Raymond Lee

    1991-01-01

    A thermal model which simulates combined conduction and phase change characteristics of thermal energy storage (TES) materials is presented. Both the model and results are presented for the purpose of benchmarking the conduction and phase change capabilities of recently developed and unvalidated microgravity TES computer programs. Specifically, operation of TES-1 is simulated. A two-dimensional SINDA85 model of the TES experiment in cylindrical coordinates was constructed. The phase change model accounts for latent heat stored in, or released from, a node undergoing melting and freezing.

  16. Dynamic cross-flow filtration: enhanced continuous small-scale solid-liquid separation.

    PubMed

    Gursch, Johannes; Hohl, Roland; Dujmovic, Diana; Brozio, Jörg; Krumme, Markus; Rasenack, Norbert; Khinast, Johannes

    2016-06-01

    In a previous study, a small-scale dynamic filtration device (SFD) was analyzed and the basic mechanisms governing the filtration process were characterized. The present work aims at improving the device's performance in terms of actual production. Various operation modes were tested in order to increase permeate flow and concentration factors (CF), while maintaining a fully continuous production mode. Both, a vacuum-enhanced and a pulsating operation mode, proved to be superior to the currently implemented open-operation mode. For example, for lactose, an increase of the CF could be achieved from 1.7 in open mode to 7.6 in pulsating operation mode. The investigated operation strategy enables process control systems to rapidly react to fluctuating feeds that may occur due to changes in upstream manufacturing steps. As a result, not only filtration performance in terms of permeate rate but also process flexibility can be significantly increased. Overall, vacuum-enhanced operation was shown to be most promising for integration into an industrial environment. The option to elevate achievable concentration factors, ease of flow monitoring as well as the ability to react to changes in the feed conditions allow for effective and efficient continuous small-scale filtration. PMID:26489453

  17. Solid-liquid distribution of selected concrete admixtures in hardened cement pastes

    SciTech Connect

    Glaus, Martin A.

    2006-07-01

    The distribution between hardened cement paste and cement pore water of selected concrete admixtures (BZMs), i.e., sulfonated naphthalene-formaldehyde condensate (NS), lignosulfonate (LS) and a gluconate-containing plasticiser used at the Paul Scherrer Institute for waste conditioning, was measured. Sorption data were fitted to a single-site Langmuir isotherm with affinity constants K = (19 {+-} 4) dm{sup 3} g{sup -1} for NS, K = (2.1 {+-} 0.6) dm{sup 3} g{sup -1} for LS and sorption capacities q = (81 {+-} 16) g kg{sup -1} for NS, q = (43 {+-} 8) g kg{sup -1} for LS. In the case of gluconate, a two-site Langmuir sorption model was necessary to fit the data satisfactorily. Sorption parameters for gluconate were K {sub 1} = (2 {+-} 1) x 10{sup 6} dm{sup 3} mol{sup -1} and q {sub 1} = (0.04 {+-} 0.02) mol kg{sup -1} for the stronger binding site and K {sub 2} = (2.6 {+-} 1.1) x 10{sup 3} dm{sup 3} mol{sup -1} and q {sub 2} = (0.7 {+-} 0.3) mol kg{sup -1} for the weaker binding site. Desorption of these BZMs from cement pastes and pore water in cement specimens prepared in the presence of the BZMs were then used to test the model. It was found that only minor parts of NS and LS could be mobilised as long as the cement composition was intact, whereas the sorption of gluconate was found to be reversible. The Langmuir model makes valuable predictions in the qualitative sense in that the pore water concentration of the BZMs is reduced by several orders of magnitude as compared to the initial concentrations. In view of the necessity for conservative predictions used in the safety analysis for disposal of radioactive waste, however, the predictions are unsatisfactory in that the measured pore water concentrations of NS and LS were considerably larger than the predicted values. This conclusion does not apply for gluconate, because its concentration in cement pore water was below the detection limit of {approx}50 nM.

  18. Observations of anisotropic wetting in solid-liquid PbGa alloys

    NASA Astrophysics Data System (ADS)

    Cheng, Wei-Chun; Chatain, Dominique; Wynblatt, Paul

    1995-04-01

    The equilibrium wetting of Pb-rich solid by Ga-rich liquid has been investigated between 560 K and the monotectic temperature (586 K) of the GaPb system. The distribution of liquid on the surface of Pb-rich crystals, 10 to 20 μm in size, has been studied. At temperatures below 570 K (i.e. some 16 K or more below the monotectic temperature) the Ga-rich liquid is distributed in droplets in a three-fold pattern around the [lcub]111[rcub] facets on the Pb crystal. The wetted orientations are close to [lcub]210[rcub], which have the highest surface free energy of the crystal. Between 570 K and the monotectic temperature, the Ga drops move away from the [lcub]210[rcub] poles. This is hypothesized to be connected with surface premelting phenomena.

  19. High-precision measurements of molecular slip at a solid/liquid interface

    NASA Astrophysics Data System (ADS)

    Pye, Justin; Wood, Clay; Burton, Justin

    As fluidic devices get smaller and measurements become more precise and stringent, the need to fully understand the dynamics at interfaces becomes more important. It is now clear that slip near an interface is common at the nanoscale in Newtonian liquids. In simple systems, there is a general trend to larger slip lengths for non-wetting liquid/solid combinations, but many conflicting measurements and interpretations remain. We have developed a novel differential technique using a quartz crystal microbalance (QCM) to measure slip lengths on various substrates. A drop of one liquid is grown on the QCM in the presence of a second, ambient liquid. By choosing the two liquids such that their bulk effects on the QCM frequency and dissipation are identical in the presence of no-slip, we are able to isolate anomalous boundary effects due to interfacial slip. Our data for water on gold (in undecane) are consistent with a slip length of 5nm (for water). A glass surface, wetted by both gold and undecane has also shown strongly anomalous results for the water-undecane pair. In addition to investigating other liquid pairs, future work will include extending this technique to surfaces with independently controllable chemistry and roughness, both of which are known to strongly affect interfacial hydrodynamics.

  20. Dependence of solid-liquid interface free energy on liquid structure

    SciTech Connect

    Wilson, S R; Mendelev, M I

    2014-09-01

    The Turnbull relation is widely believed to enable prediction of solid–liquid interface (SLI) free energies from measurements of the latent heat and the solid density. Ewing proposed an additional contribution to the SLI free energy to account for variations in liquid structure near the interface. In the present study, molecular dynamics (MD) simulations were performed to investigate whether SLI free energy depends on liquid structure. Analysis of the MD simulation data for 11 fcc metals demonstrated that the Turnbull relation is only a rough approximation for highly ordered liquids, whereas much better agreement is observed with Ewing’s theory. A modification to Ewing’s relation is proposed in this study that was found to provide excellent agreement with MD simulation data.

  1. Chemically selective NMR imaging of a 3-component (solid-solid-liquid) sedimenting system.

    PubMed

    Beyea, Steven D; Altobelli, Stephen A; Mondy, Lisa A

    2003-04-01

    A novel magnetic resonance imaging (MRI) technique which resolves the separate components of the evolving vertical concentration profiles of 3-component non-colloidal suspensions is described. This method exploits the sensitivity of MRI to chemical differences between the three phases to directly image the fluid phase and one of the solid phases, with the third phase obtained by subtraction. 19F spin-echo imaging of a polytetrafluoroethylene (PTFE) oil was interlaced with 1H SPRITE imaging of low-density polyethylene (LDPE) particles. The third phase was comprised of borosilicate glass spheres, which were not visible while imaging the PTFE or LDPE phases. The method is demonstrated by performing measurements on 2-phase materials containing only the floating (LDPE) particles, with the results contrasted to the experimental behaviour of the individual phases in the full 3-phase system. All experiments were performed using nearly monodisperse particles, with initial suspension volume fractions, phi(i), of 0.1. PMID:12713970

  2. Quantification of ordering at a solid-liquid interface using plasmon electron energy loss spectroscopy

    SciTech Connect

    Gandman, Maria; Kauffmann, Yaron; Kaplan, Wayne D.

    2015-02-02

    We present an in situ electron energy loss spectroscopy (EELS) study of ordering of liquid Al at various Al-Al{sub 2}O{sub 3} interfaces. This technique utilizes precise measurements of the shifts in bulk plasmon resonance and their sensitivity to the valence electron density. Plasmon EELS combined with high resolution transmission electron microscopy provides information regarding the chemical composition in liquid Al at Al-Al{sub 2}O{sub 3} interfaces. Preferential oxygen segregation to the (0006) Al{sub 2}O{sub 3} plane was verified, and the (101{sup ¯}2) Al{sub 2}O{sub 3} plane was found to contain the lowest amount of segregated species.

  3. A Laboratory Experiment for Measuring Solid-Liquid Mass Transfer Parameters

    ERIC Educational Resources Information Center

    Dapia, Sonia; Vila, Carlos; Dominguez, Herminia; Parajo, Juan Carlos

    2004-01-01

    The lab experiment described starts from the principles developed by Sensel and Myers, but the experimental procedure are modified to provide a more reliable experiment assessment. The mass transfer equation is solved and all the involved parameters are calculated by a simple, numerical method.

  4. Unravelling the electrochemical double layer by direct probing of the solid/liquid interface.

    PubMed

    Favaro, Marco; Jeong, Beomgyun; Ross, Philip N; Yano, Junko; Hussain, Zahid; Liu, Zhi; Crumlin, Ethan J

    2016-01-01

    The electrochemical double layer plays a critical role in electrochemical processes. Whilst there have been many theoretical models predicting structural and electrical organization of the electrochemical double layer, the experimental verification of these models has been challenging due to the limitations of available experimental techniques. The induced potential drop in the electrolyte has never been directly observed and verified experimentally, to the best of our knowledge. In this study, we report the direct probing of the potential drop as well as the potential of zero charge by means of ambient pressure X-ray photoelectron spectroscopy performed under polarization conditions. By analyzing the spectra of the solvent (water) and a spectator neutral molecule with numerical simulations of the electric field, we discern the shape of the electrochemical double layer profile. In addition, we determine how the electrochemical double layer changes as a function of both the electrolyte concentration and applied potential. PMID:27576762

  5. Using Peltier Cells to Study Solid-Liquid-Vapour Transitions and Supercooling

    ERIC Educational Resources Information Center

    Torzo, Giacomo; Soletta, Isabella; Branca, Mario

    2007-01-01

    We propose an apparatus for teaching experimental thermodynamics in undergraduate introductory courses, using thermoelectric modules and a real-time data acquisition system. The device may be made at low cost, still providing an easy approach to the investigation of liquid-solid and liquid-vapour phase transitions and of metastable states…

  6. Nuclear magnetic resonance measurement of ammonia diffusion in dense solid-liquid slurries

    SciTech Connect

    Bobroff, S.; Phillips, R.J.; Shekarriz, A.

    1997-09-01

    The diffusion of ammonium ions in aqueous solutions was measured by nuclear magnetic resonance (NMR) using the pulsed field gradient (PFG) method. The ammonium ions were obtained from aqueous solutions of ammonium chloride, ammonium sulfate, ammonium bicarbonate, and ammonium hydroxide. The translation diffusion of the ammonium ions was determined by measuring the diffusion of nitrogen nuclei ({sup 14}N and {sup 15}N) in solution. Our results showed that the ammonium diffusion coefficient can be measured in aqueous solutions with concentrations as low as 20 x 10{sup -3} M. Typical values measured for the diffusion coefficient of the ammonium ion are 2 x 10{sup -5} cm{sup 2/s} ({+-}10%), similar to the values found for pure water. Due to the effect of the solution pH upon the NMR relaxation parameters for {sup 14}N, measurements are constrained to pH values below 8.5. However, {sup 15}N labeled ammonium is less sensitive to the solution pH, extending the measurement range to pH of 9.5. Diffusion measurements were conducted with solutions of varying viscosity and porosity. The results show that the solution viscosity has a measureable impact on the diffusion coefficient. The diffusion coefficient is almost inversely proportional to the relative viscosity of the solution, irrespective of how the viscosity is increased. Further, a randomly-packed porous bed of 200 mm PMMA resulted in a reduction of {approximately}30% in the diffusion coefficient as a result of hindered diffusion.

  7. Nuclear magnetic resonance measurement of ammonia diffusion in dense solid-liquid slurries. Revision 1

    SciTech Connect

    Bobroff, S.; Phillips, R.J.; Shekarriz, A.

    1998-01-01

    The flammability and toxicity of ammonia released from the nuclear waste tanks at Hanford have been the subject of several recent studies. These releases may occur episodically, such as the buoyant plume releases occurring in various double-shell tanks (DSTs); gradually through the surface of the waste; or from the partially saturated saltcakes in the single-shell tanks during salt-well pumping. The diffusion of ammonium ions in aqueous solutions was measured by nuclear magnetic resonance (NMR) using the pulsed field gradient (PFG) method. The ammonium ions were obtained from aqueous solutions of ammonium chloride, ammonium sulfate, ammonium bicarbonate, and ammonium hydroxide. The translational diffusion of the ammonium ions was determined by measuring the diffusion of nitrogen nuclei in solution. Results showed that the ammonium diffusion coefficient can be measured in aqueous solutions with concentrations as low as 20 {times} 10{sup {minus}3} {und M}. Typical values measured for the diffusion coefficient of the ammonium ion are 2 {times} 10{sup {minus}5} cm{sup 2}/s ({+-}10%), similar to the values found for pure water. Due to the effect of the solution pH upon the NMR relaxation parameters for {sup 14}N, measurements are constrained to pH values below 8.5. However, {sup 15}N labeled ammonia is less sensitive to the solution pH, extending the measurement range to pH of 9.5. The results show that the solution viscosity has a measurable impact on the diffusion coefficient. The diffusion coefficient is almost inversely proportional to the relative viscosity of the solution, irrespective of how the viscosity is increased. Further, a randomly-packed porous bed of 200 {micro}m PMMA resulted in a reduction of {approximately} 30% in the diffusion coefficient as a result of hindered diffusion.

  8. Protein adsorption, desorption, and aggregation mediated by solid-liquid interfaces.

    PubMed

    Perevozchikova, Tatiana; Nanda, Hirsh; Nesta, Douglas P; Roberts, Christopher J

    2015-06-01

    Adsorption of proteins to solid-fluid interfaces is often empirically found to promote formation of soluble aggregates and larger, subvisible, and visible particles, but key stages in this process are often difficult to probe directly. Aggregation mediated by adsorption to water-silicon oxide (SiOx) interfaces, akin to hydrated glass surfaces, was characterized as a function of pH and ionic strength for alpha-chymotrypsinogen (aCgn) and for a monoclonal antibody (IgG1). A flow cell permitted neutron reflectivity for protein layers adsorbed to clean SiOx surfaces, as well as after successive "rinse" steps. Aggregates recovered in solution after gently "rinsing" the surface were characterized by neutron scattering, microscopy, and fluorescence spectroscopy. IgG1 molecules oriented primarily "flat" against the SiOx surface, with the primary protein layer desorbed to a minimal extent, whereas a diffuse overlayer was easily rinsed off. aCgn molecules were resistant to desorption when they appeared to be unfolded at the interface, but were otherwise easily removed. For cases where strong binding occurred, protein that did desorb was a mixture of monomer and small amounts of HMW aggregates (for aCgn) or subvisible particles (for IgG1). Changes in adsorption and/or unfolding with pH indicated that electrostatic interactions were important in all cases. PMID:25846460

  9. Toxicity testing of marine, terrestrial, solid, liquid, clear, and turbid samples

    SciTech Connect

    Sabate, R.W.; Stiffey, A.V.; Dewailly, E.L.

    1994-12-31

    A novel, patented toxicity testing procedure that compares the light generated by the naturally bioluminescent marine dinoflagellate alga, Pyrocystis lunula, in the presence of toxins, to light from a non-toxic control, is sensitive in parts per billion to all substances considered toxic to which it has been subjected: chemical warfare agents, metals, detergents, pesticides, herbicides, anticancer drugs, oil-well drilling fluids and produced waters, marine antifouling paints, and others. Preparation and testing time is less than eight hours. Variability is 10% or less. Solids and turbid or darkly colored samples can be tested without correction. Small sample substrates (10 to 50{mu}l) in the buffered 3ml test medium do not significantly affect pH or salinity, which permits testing of marine or terrestrial samples without special preparation. Also, the organism is insensitive to selected solvents for lipophyllic test substances. EC{sub 50} of sodium lauryl (dodecyl) sulphate is 3.7 ppm, and correlation with the Mysid LC{sub 50} EPA 30,000 ppm toxicity limit is 63% light inhibition.

  10. The influence of the solid/liquid interface on the dewetting of ultra thin polymer films

    NASA Astrophysics Data System (ADS)

    Lessel, Matthias; Klos, Mischa; Baeumchen, Oliver; Jacobs, Karin

    2012-02-01

    In recent years, many studies showed that a thin liquid film on a solid surface in air bears more complexity than expected from a simple three-layer-system: e.g. a highly mobile surface layer in case the liquid is an unentangled polystyrene (PS) melt (Yang et al., Science 2010; Seemann et al., J. of Polym. Sci. 2006) or the PS melt can slip over the solid substrate (Baeumchen et al., PRL 2009). Our study focuses on such phenomena and explores their influence on dewetting (speed, morphology, etc.). We use hydrophilic and -phobic Si wafer (either covered by a highly ordered silane layer or by a thin layer of an amorphous fluoropolymer, AF 1600). On each of the substrates, one expects for a certain set of parameters spinodal dewetting for the PS melt. Yet experimentally, a much higher hole density is observed for both types of hydrophobic wafers than is theoretically expected. Moreover, the two hydrophobic coatings induce different dewetting speeds: the PS melt dewets faster on the silane covered Si wafer. The difference is attributed to slip (silane) or to no slip (AF 1600) conditions at the PS/substrate interface, which is also observable in the type of liquid front profile, which in turn changes the dewetting morphology.

  11. Effect of the energy density of a solid-liquid meal on gastric emptying and satiety.

    PubMed

    Carbonnel, F; Lémann, M; Rambaud, J C; Mundler, O; Jian, R

    1994-09-01

    The effect of the energy density of a meal on gastric emptying and satiety was assessed in nine volunteers. They ingested, in randomized order, a diluted (2671 kJ/L, 950 mL) and a concentrated (7452 kJ/L, 350 mL) test meal of 2500 kJ each (80% as solids). Half-emptying times of solids and liquids were not significantly different for the diluted and concentrated meal (solids: 145 +/- 18 and 156 +/- 16 min, respectively; liquids: 76 +/- 10 and 84 +/- 10 min, respectively), and consequently, pyloric outputs of energy were identical. Neither the intensity and duration of satiety, nor the amount of energy ingested, ad libitum, 6 h after the test meal, were significantly affected by energy density of the food ingested. Both the intensity and duration of satiety correlated significantly with the gastric emptying time for solids (r = 0.60 and 0.67, respectively, P < 0.01). These results show that satiety depends on gastric emptying of energy and is not affected by the energy density of food intake. PMID:8074058

  12. Quartz Crystal Microbalance Studies of Multilayer Glucagon Fibrillation at the Solid-Liquid Interface

    PubMed Central

    Hovgaard, Mads Bruun; Dong, Mingdong; Otzen, Daniel Erik; Besenbacher, Flemming

    2007-01-01

    We have used a quartz crystal microbalance with dissipation (QCM-D) to monitor the changes in layer thickness and viscoelastic properties accompanying multilayer amyloid deposition in situ for the first time. By means of atomic force microscope imaging, an unequivocal correlation is established between the interfacial nucleation and growth of glucagon fibrils and the QCM-D response. The combination of the two techniques allows us to study the temporal evolution of the interfacial fibrillation process. We have modeled the QCM-D data using an extension to the Kelvin-Voigt viscoelastic model. Three phases were observed in the fibrillation process: 1), a rigid multilayer of glucagon monomers forms and slowly rearranges; 2), this multilayer subsequently evolves into a dramatically more viscoelastic layer, containing a polymorphic network of micrometer-long fibrils growing from multiple nucleation sites; and 3), the fibrillar formation effectively stops as a result of the depletion of bulk-phase monomers, although the process can be continued without a lag phase by subsequent addition of fresh monomers. The robustness of the QCM-D technique, consolidated by complementary atomic force microscope studies, should make it possible to combine different components thought to be involved in the plaque formation process and thus build up realistic models of amyloid plaque formation in vitro. PMID:17513349

  13. Solid-liquid like phase transition in a confined granular suspension

    NASA Astrophysics Data System (ADS)

    Sakai, Nariaki; Lechenault, Frederic; Adda Bedia, Mokhtar

    We present an experimental study of a liquid-solid like phase transition in a two-dimensional granular media. Particles are placed in a vertical Hele-Show cell filled with a denser solution of cesium-chloride. Thus, when the cell is rotated around its axis, hydrostatic pressure exerts a centripetal force on the particles which confines them towards the center. This force is in competition with gravity, thus by modifying the rotation rate, it is possible to transform continuously and reversibly the sample from a disordered loose state to an ordered packed state. The system presents many similarities with thermal systems at equilibrium like density and interface fluctuations, and the transition between the two phases goes through a coexistence state, where there is nucleation and growth of locally ordered domains which are captured by the correlation function of the hexatic order parameter. We discuss the possibility to extend the grand-canonical formalism to out-of equilibrium systems, in order to uncover a state equation between the density and the pressure in the medium.

  14. SESAME 96170, a solid-liquid equation of state for CeO2

    SciTech Connect

    Chisolm, Eric D.

    2014-05-02

    I describe an equation of state (EOS) for the low-pressure solid phase and liquid phase of cerium (IV) oxide, CeO2. The models and parameters used to calculate the EOS are presented in detail, and I compare with data for the full-density crystal. Hugoniot data are available only for high-porosity powders, and I discuss difficulties in comparing with such data. I have constructed SESAME 96170, an EOS for cerium (IV) oxide that includes the ambient solid and liquid phases. The EOS extends over the full standard SESAME range, but should not be used at low temperatures and high densities because of the lack of a high-pressure solid phase. I have described the models used to compute the three terms of the EOS (cold curve, nuclear, and thermal electronic), and I have given the parameters used in the models. They were determined by comparison with experimental data at P = 1 atm, including the constant-pressure specific heat, coefficient of thermal expansion, and melting and boiling points. The EOS compares well with data in its intended range of validity, but the presence of high-frequency optical modes in its phonon spectrum limits the agreement of our models with thermal data. The next step is to construct a multiphase EOS that includes the low- and high-pressure solid phases and the liquid. The DAC data from Duclos will most strongly constrain the parameters of the high-pressure solid. A remaining issue is the comparison of the crystal-density EOS with experimental Hugoniot data, which are taken at much lower initial data because the samples are porous powders. A satisfactory means of modeling porosity, allowing comparison of theory and experiment, has not yet been produced.

  15. Solid-liquid interfaces of ionic liquid solutions—Interfacial layering and bulk correlations

    NASA Astrophysics Data System (ADS)

    Mezger, Markus; Roth, Roland; Schröder, Heiko; Reichert, Peter; Pontoni, Diego; Reichert, Harald

    2015-04-01

    The influence of the polar, aprotic solvent propylene carbonate on the interfacial structure of the ionic liquid (IL) 1-butyl-1-methylpyrrolidinium tris(pentafluoroethyl)trifluorophosphate on sapphire was investigated by high-energy x-ray reflectivity. Experiments at solvent concentrations between 17 mol. % and 83 mol. % bridge the gap between diluted electrolytes described by the classical Gouy-Chapman theory and pure ionic liquids. Analysis of our experimental data revealed interfacial profiles comprised of alternating anion and cation enriched regions decaying gradually into the bulk liquid. With increasing solvent concentration, we observed a decrease in correlation length of the interfacial layering structure. At high ion concentrations, solvent molecules were found to accumulate laterally within the layers. By separating like-charged ions, they reduce their Coulomb repulsion. The results are compared with the bulk structure of IL/solvent blends probed by x-ray scattering and predictions from fundamental fluid theory.

  16. Teaching Sustainable Development Concepts in the Laboratory: A Solid-Liquid Extraction Experiment

    ERIC Educational Resources Information Center

    Parajo, Juan Carlos; Dominguez, Herminia; Santos, Valentin; Alonso, Jose Luis; Garrote, Gil

    2008-01-01

    One of the principles of sustainable development is to replace chemicals traditionally derived from oil with alternative, renewable materials. For example, phenol and phenol derivatives currently used in the manufacture of wood adhesives can be replaced (at least in part) by biopolymers extracted from biomass. In this work, pine bark (a renewable…

  17. ADSORPTION OF SURFACTANTS AND POLYMERS AT THE SOLID-LIQUID INTERFACE. (R823301)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  18. ELECTRON TRANSFER MECHANISM AT THE SOLID-LIQUID INTERFACE OF PHYLLOSILICATES

    EPA Science Inventory

    Interfacial electron transfer processes on clay minerals have significant impact in natural environments and geochemical systems. Nitrobenzene was used as molecular probes to study the electron transfer mechanism at the solid-water interfaces of Fe-containing phyllosicates. For...

  19. Parallel gastric emptying of nonhydrolyzable fat and water after a solid-liquid meal in humans

    SciTech Connect

    Cortot, A.; Phillips, S.F.; Malagelada, J.R.

    1982-05-01

    Our aim was to examine the control of gastric emptying of the oil phase of a mixed solid and liquid meal. Previous studies had shown that liquid dietary fats normally leave the stomach at a slower rate than does water. We wished to determine whether the slower emptying of fats was due to the physical characteristics of food (lower density and greater viscosity than water), to retardation by duodenal feedback mechanisms, or whether both factors contributed. Thus, we quantified the emptying rates of water and sucrose polyester (a nonabsorbable analog of dietary fat) ingested by healthy volunteers as a mixed solid and liquid meal. Gastric emptying was quantified by an intubation-perfusion method incorporating an occlusive jejunal balloon to facilitate recovery. Four phase-specific, nonabsorbable markers were used. (14C(Sucrose octaoleate and polyethylene glycol were incorporated in the meal and traced the lipid and water phases, respectively; (3H)glycerol triether and phenolsulfonphthalein were used as duodenal recovery markers. Sucrose polyester (substituting for dietary fat) was emptied very rapidly, and at about the same rate as was water, in contrast to natural fat, which empties very slowly. Emptying of water was rapid and comparable to that observed after mixed meals containing natural fat. These results imply that gastric emptying of the oil phase is controlled by receptors sensitive to the hydrolytic products of fat digestion and that the slow emptying of dietary fat is not simply due to its lower density.

  20. How to quantify solid-liquid phase transition: Lennard-Jones system case study

    NASA Astrophysics Data System (ADS)

    Klumov, Boris A.; Klumov

    2013-12-01

    In this paper we analyzed different measures, characterizing the melting of Lennard-Jones solid, and associated with the properties of both the translational and the orientational local order. It has been shown that the most sensitive indicator of melting is the cumulant of the probability distribution function over w 6 bond-order parameter. The criterion of melting based on the indicator is proposed; the criterion can be used for any solids, having fcc/hcp types of symmetry.

  1. Using Laser-Induced Thermal Voxels to Pattern Diverse Materials at the Solid-Liquid Interface.

    PubMed

    Zarzar, Lauren D; Swartzentruber, B S; Donovan, Brian F; Hopkins, Patrick E; Kaehr, Bryan

    2016-08-24

    We describe a high-resolution patterning approach that combines the spatial control inherent to laser direct writing with the versatility of benchtop chemical synthesis. By taking advantage of the steep thermal gradient that occurs while laser heating a metal edge in contact with solution, diverse materials comprising transition metals are patterned with feature size resolution nearing 1 μm. We demonstrate fabrication of reduced metallic nickel in one step and examine electrical properties and air stability through direct-write integration onto a device platform. This strategy expands the chemistries and materials that can be used in combination with laser direct writing. PMID:27491598

  2. Physical Characterization of Solid-Liquid Slurries at High Weight Fractions Using Optical and Ultrasonic Methods

    SciTech Connect

    Burgess, L.W.; Brodsky, A.M.; Panetta P.D.

    2005-12-22

    Remediation of highly radioactive waste is a major technical and programmatic challenge for the DOE. Rapid, on-line physical characterization of highly concentrated slurries is required for the safe and efficient remediation of 90 million gallons of high level radioactive waste (HLW), sodium bearing waste, and mixed waste. The research presented here, describes a collaborative effort between Pacific Northwest National Laboratory (PNNL) and the University of Washington (UW) to directly address the need for rapid on-line characterization of the physical properties of HLW slurries during all phases of the remediation process, from in-tank characterization of sediments to monitoring of the concentration, particle size, and degree of agglomeration and gelation of slurries during transport. Near-surface characterization of the slurry flow in the particle size range from nanometer to micrometer is examined using optical low coherence reflectometry. Volumetric characterization at depths in the slurry flow, up to several centimeters in the particle size range from the micrometer to millimeter, is realized by utilizing ultrasonic backscatter and diffuses fields. One of the strengths, the teaming up of significant talents in both experimental and theoretical optics and in ultrasonics, provides a synergistic approach to integrate these complimentary techniques. One of the benefits of this combined approach is the physical characterization of HLW over a concentration and particle size range that is broader than can be achieved with today's technology. This will avoid a costly increase in waste stream volume due to excess dilution, and will lessen chance of plugging pipes that could shut down expensive processing lines.

  3. Depletion at Solid-Liquid Interfaces under Shear: Flowing Hexadecane on Functionalized Surfaces

    SciTech Connect

    Guttfreund, Philipp; Wolff, Max; Maccarini, Marco; Gerth, Stefan; Ankner, John Francis; Browning, Jim; Halbert, Candice E; Wacklin, Hanna; Zabel, Hartmut

    2011-01-01

    We present a neutron reflectivity study on the interface of flowing hexadecane, which is known to exhibit surface slip on functionalized solid surfaces. The single crystalline silicon substrates are either chemically cleaned or covered by octadecyl-trichlorosilane (OTS) which result in different interfacial energies in respect to hexadecane. The liquid is in situ sheared and the reflectivities are compared to the static case. Moreover, the temperature dependence is recorded. For both types of interface, density depleted layers are observed, but shear affects them differently. Whereas at the attractive surface the depletion is enhanced by shear, the low interfacial energy leads to a diminishment of the depleted layer when applying shear. This systematic change of the depletion layer indicates different structural rearrangements under shear load. Finally, the possible link of the depletion layer with surface slip is discussed.

  4. Use of sol-gel systems for solid/liquid separation.

    SciTech Connect

    Chaiko, D. J.; Kopasz, J. P.; Elison, A. J. G.; Chemical Engineering

    1998-01-01

    A unique approach using sol-gel technology is presented for separating and recovering particulates and colloids from caustic waste slurries. The approach involves the addition of an alkali silicate and an organic gelling agent directly to the waste stream to immobilize particulates that range from macro sizes to submicron colloids. The particulates and colloids become trapped within a silica network that remains porous during the early stages of the sol-gel process. The freshly gelled monolith undergoes a process of syneresis, whereby the water and soluble salts are ejected from the monolith as it contracts. The approach has been illustrated by removal of ultrafine particulates from a Hanford Tank Waste simulant. Initial laboratory tests have shown that it is possible to produce silica monoliths in the presence of 4 M hydroxide. Analysis of the mother liquor produced during syneresis indicated quantitative recovery of the particulates within the monolith. The partitioning of ions between the silica gel and the mother liquor during syneresis correlates directly with the lyotropic series. Salt recoveries from the mother liquor in excess of 90% can be achieved. With a capability of recovering >99.999% of all particulates, including colloids, the process is more efficient than membrane filtration. This approach produces a rock-hard silica monolith that can be used directly as a feedstock to a glass melter or can be consolidated to near theoretical density by sintering.

  5. Simulation of microsegregation and the solid/liquid interface progression in the concentric solidification technique

    NASA Astrophysics Data System (ADS)

    Aminorroaya, Sima; Reid, Mark; Dippenaar, Rian

    2011-03-01

    A concentric solidification technique was employed to simulate experimentally the segregation of alloying elements during solidification at the centerline of continuously cast steel. Microstructural development of low carbon steel upon solidification has been observed in situ in a laser-scanning confocal microscope. Microscopic analyses following in situ observations, demonstrate that segregation occurring at steel slabs can reasonably be simulated by the use of the concentric solidification technique. The validity of these experimental simulations has been correlated with mathematical analyses using the Thermo-Calc and DICTRA (Diffusion Controlled Transformation) modeling tools. The effect of cooling rate on the sequence of events during solidification of Fe-0.18%C and Fe-4.2 wt%Ni peritectic alloys was studied and compared with the experimental observations.

  6. Solid-liquid separation of dairy manure with PAM and chitosan polymers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic polymers are useful to increase separation of suspended solids and carbon compounds from liquid swine manure, but experiences with dairy manure are limited. In this experiment, two polymers, a synthetic polyacrylamide (PAM) and a natural chitosan were used to increase separation of suspended...

  7. Eliminating unwanted nanobubbles from hydrophobic solid/liquid interfaces: a case study using magnetoelastic sensors.

    PubMed

    Feng, Xinjian; Roy, Somnath C; Grimes, Craig A

    2008-04-15

    Air bubbles are known to form at the liquid/solid interface of hydrophobic materials upon immersion in a liquid (Holmberg, M.; Kdühle, A.; Garnaes, J.; Mørch, K. A.; Boisen, A. Langmuir 2003, 19, 10510-10513). In the case of gravimetric sensors, air bubbles that randomly form at the liquid-solid interface result in poor sensor-to-sensor reproducibility. Herein a superhydrophilic ZnO nanorod film is applied to the originally hydrophobic surface of a resonance-based magnetoelastic sensor. The superhydrophilic coating results in the liquid completely spreading across the surface, removing unwanted air bubbles from the liquid/sensor interface. The resonance amplitude of uncoated (bare) and ZnO-modified sensors are measured in air and then when immersed in saline solution, ethylene glycol, or bovine blood. In comparison to the bare, hydrophobic sensors, we find that the standard deviation of the resonance amplitudes of the liquid-immersed ZnO-nanorod-modified sensors decreases substantially, ranging from a 27% decrease for bovine blood to a 67% decrease for saline. The strategy of using a superhydrophilic coating can be applied to other systems having similar interfacial problems. PMID:18307368

  8. Evolution de la résistance aux antibiotiques des entérobactéries isolées à l'Hôpital Général de Douala de 2005 à 2012

    PubMed Central

    Ebongue, Cécile Okalla; Tsiazok, Martial Dongmo; Mefo'o, Jean Pierre Nda; Ngaba, Guy Pascal; Beyiha, Gérard; Adiogo, Dieudonné

    2015-01-01

    Introduction Cette étude vise à déterminer le profil de résistance aux antibiotiques des entérobactéries isolées à l'Hôpital Général de Douala (Cameroun) et analyser leur évolution dans le temps. Méthodes Etude rétrospective, sur une période de huit ans (2005 - 2012), portant sur l'ensemble des souches d'entérobactéries isolées chez les malades ambulatoires et hospitalisés. Les prélèvements ont été analysés au laboratoire de bactériologie de l'Hôpital Général de Douala. Résultats Les entérobactéries étaient les germes les plus fréquents sur l'ensemble des souches isolées. Nous avons noté une prédominance d’Escherichia coli (48,5%) et de Klebsiella pneumoniae (32,8%). Pendant la période d’étude, nous avons observé des taux de résistance élevés aux principales classes d'antibiotiques, et une augmentation entre 2005 et 2012 de 29,1% à 51,6% pour les céphalosporines de troisième génération, de 29,2% à 44% pour la ciprofloxacine. L'imipénème, l'amikacine et la fosfomycine étaient les molécules les plus actives avec respectivement 1,3%, 12,9% et 13,4% des souches d'entérobactéries résistantes. Conclusion L’évolution des résistances des entérobactéries aux antibiotiques est un phénomène réel dans la ville de Douala. Il expose à des difficultés de prise en charge thérapeutique des infections. Lamaitrise actuelle de ce phénomène est une véritable urgence et nécessite une implication des pouvoirs publics. Des tests spécifiques de recherche des bétalactamases à spectre élargi (BLSE) et AmpC doivent être mis en place dans nos laboratoires afin de mettre en évidence les différents phénotypes de résistances. PMID:26140070

  9. Application of forward osmosis (FO) under ultrasonication on sludge thickening of waste activated sludge.

    PubMed

    Nguyen, Nguyen Cong; Nguyen, Hau Thi; Chen, Shiao-Shing; Nguyen, Nhat Thien; Li, Chi-Wang

    2015-01-01

    Forward osmosis (FO) is an emerging process for dewatering solid-liquid stream which has the potential to be innovative and sustainable. However, the applications have still been hindered by low water flux and membrane fouling when activated sludge is used as the feed solution due to bound water from microbial cells. Hence, a novel strategy was designed to increase sludge thickening and reduce membrane fouling in the FO process under ultrasonic condition. The results from the ultrasound/FO hybrid system showed that the sludge concentration reached up to 20,400 and 28,400 mg/L from initial sludge concentrations of 3000 and 8000 mg/L with frequency of 40 kHz after 22 hours, while the system without ultrasound had to spend 26 hours to achieve the same sludge concentration. This identifies that the presence of ultrasound strongly affected sludge structure as well as sludge thickening of the FO process. Furthermore, the ultrasound/FO hybrid system could achieve NH4+-N removal efficiency of 96%, PO4(3-)-P of 98% and dissolved organic carbon (DOC) of 99%. The overall performance demonstrates that the proposed ultrasound/FO system using seawater as a draw solution is promising for sludge thickening application. PMID:26465299

  10. RE16AuxAl13-x with RE = La-Nd, Sm (x≤ 3.37): synthesis, crystal structure and physical properties of an intermetallic solid solution with barrelane analogue units.

    PubMed

    Stegemann, Frank; Janka, Oliver

    2016-09-21

    During phase analytical investigations in the rare-earth element rich side of the ternary system cerium-gold-aluminum, the new ternary rare-earth (RE) gold aluminides with a composition of RE16AuxAl13-x (RE = La-Nd, Sm, x≤ 3.37) have been synthesized first by reactive eutectics of RE/Au with Al. Single crystals of high quality can be obtained by this method. The title compounds can be selectively prepared by annealing arc-melted beads of appropriate composition below the peritectic point of the respective system. Like prototypic La16Al13, the representatives of the solid solution RE16AuxAl13-x (RE = La-Nd, Sm; x≤ 3.37) crystallize in the hexagonal crystal system (space group P6[combining macron]2m, a = 916.6-890.4 pm, c = 1122.4-1090.1 pm) with one formula unit per unit cell. Single crystal investigations revealed Au/Al mixing on three of the four crystallographic aluminum sites. These sites form an empty (Au/Al)11 barrelane analogous unit, coordinated solely by the respective rare-earth atoms. In addition one independent Al site with a fivefold capped trigonal prismatic arrangement, a so called Edshammar polyhedron, exists. Magnetic measurements of Ce16Au3Al10 revealed two antiferromagnetic transitions with Neél-temperatures of 7.7(1) and 2.7(1) K and a magnetic moment of μeff = 2.48(1) μB, Pr16Au3Al10 shows ferromagentic ordering with a Curie-temperature of 19.8(1) K and a magnetic moment of μeff = 3.58(1) μB. PMID:27512911

  11. Admission Requirements to Canadian Faculties of Medicine and Their Selection Policies = Conditions d'Admission aux Facultes de Medecine Canadiennes et Leurs Politiques de Selection.

    ERIC Educational Resources Information Center

    Association of Canadian Medical Colleges, Ottawa (Ontario).

    Information is presented to help applicants to Canadian medical colleges realistically assess their chances for gaining admission. The guide is also intended for career counselors in high schools and higher education. One section provides statistics on the following characteristics that are associated with being selected: sex, age, Medical College…

  12. Extension of the broadband single-mode integrated optical waveguide technique to the ultraviolet spectral region and its applications.

    PubMed

    Wiederkehr, Rodrigo S; Mendes, Sergio B

    2014-03-21

    We report here the fabrication, characterization, and application of a single-mode integrated optical waveguide (IOW) spectrometer capable of acquiring optical absorbance spectra of surface-immobilized molecules in the visible and ultraviolet spectral region down to 315 nm. The UV-extension of the single-mode IOW technique to shorter wavelengths was made possible by our development of a low-loss single-mode dielectric waveguide in the UV region based on an alumina film grown by atomic layer deposition (ALD) over a high quality fused silica substrate, and by our design/fabrication of a broadband waveguide coupler formed by an integrated diffraction grating combined with a highly anamorphic optical beam of large numerical aperture. As an application of the developed technology, we report here the surface adsorption process of bacteriochlorophyll a on different interfaces using its Soret absorption band centred at 370 nm. The effects of different chemical compositions at the solid-liquid interface on the adsorption and spectral properties of bacteriochlorophyll a were determined from the polarized UV-Vis IOW spectra acquired with the developed instrumentation. The spectral extension of the single-mode IOW technique into the ultraviolet region is an important advance as it enables extremely sensitive studies in key characteristics of surface molecular processes (e.g., protein unfolding and solvation of aromatic amino-acid groups under surface binding) whose spectral features are mainly located at wavelengths below the visible spectrum. PMID:24466569

  13. Extension of the broadband single-mode integrated optical waveguide technique to the ultraviolet spectral region and its applications

    PubMed Central

    Wiederkehr, Rodrigo S.; Mendes, Sergio B.

    2014-01-01

    We report here the fabrication, characterization, and application of a single-mode integrated optical waveguide (IOW) spectrometer capable of acquiring optical absorbance spectra of surface-immobilized molecules in the visible and ultraviolet spectral region down to 315 nm. The UV-extension of the single-mode IOW technique to shorter wavelengths was made possible by our development of a low-loss single-mode dielectric waveguide in the UV region based on an alumina film grown by atomic layer deposition (ALD) over a high quality fused silica substrate, and by our design/fabrication of a broadband waveguide coupler formed by an integrated diffraction grating combined with a highly anamorphic optical beam of large numerical aperture. As an application of the developed technology, we report here the surface adsorption process of bacteriochlorophyll a on different interfaces using its Soret absorption band centred at 370 nm. The effects of different chemical compositions at the solid/liquid interface on the adsorption and spectral properties of bacteriochlorophyll a were determined from the polarized UV-Vis IOW spectra acquired with the developed instrumentation. The spectral extension of the single-mode IOW technique into the ultraviolet region is an important advance as it enables extremely sensitive studies in key characteristics of surface molecular processes (e.g., protein unfolding and solvation of aromatic amino-acid groups under surface binding) whose spectral features are mainly located at wavelengths below the visible spectrum. PMID:24466569

  14. Séroprévalence et facteurs associés au VIH et aux hépatites virales B et C dans la ville de Bafoussam au Cameroun

    PubMed Central

    Mbopi-Keou, Francois-Xavier; Nkala, Isabelle Vanessa Monthe; Kalla, Ginette Claude Mireille; Nguefack-Tsague, Georges; Kamga, Hortense Gonsu; Noubom, Michel; Mvogo, Côme Ebana; Sosso, Maurice Aurelien

    2015-01-01

    Introduction L'objectif de ce travail était de déterminer la séroprévalence et les facteurs associés au VIH et aux hépatites virales B et C dans la ville de Bafoussam au Cameroun. Méthodes Il s'agissait d'une étude descriptive et analytique réalisée de février 2012 à Juin 2012 dans la ville de Bafoussam au Cameroun. Pour cette étude, nous avons obtenu une clairance éthique. Résultats Au total, 982 personnes ont été dépistées pour le VIH et les hépatites virales B et C. Les femmes représentaient 56,3% des personnes dépistées. La tranche d’âge la plus représentée était celle des 20 à 24 ans. L’âge médian était de 34,5 ans. Les prévalences du VIH, de l'AgHBs, et de l'Ac anti HCV étaient respectivement de 6,0%, 4,1%, et 0,4%. La prévalence du VIH était 2 fois plus élevée parmi les femmes que les hommes avec 8,1% contre 3,5% (p=0,01). Les prévalences les plus élevées ont été observées chez les personnes de 30 à 34 ans, 40 à 44 ans avec 15,0% et 11,5% (p=0,01), les personnes sans emploi avec 11,1% (p<0,001) et les personnes en union libre avec 17,9% (p=0,000). La prévalence du VIH n’était pas directement liée aux comportements et pratiques sexuels de la population de l’étude. On enregistrait une prévalence élevée de 29,3% chez les individus ayant déclaré avoir au moins une infection sexuellement transmissible (p=0,000). Conclusion Il apparait urgent de mettre en place des stratégies de prévention contre le VIH, les hépatites virales et les facteurs associés au Cameroun. PMID:26113899

  15. X-Rays Compton Detectors For Biomedical Application

    SciTech Connect

    Rossi, Paolo; Fontana, Cristiano Lino; Moschini, Giuliano; Baldazzi, Giuseppe; Navarria, Francesco; Battistella, Andrea; Bello, Michele; Bollini, Dante; Bonvicini, Valter; Rashevsky, Alexander; Zampa, Gianluigi; Zampa, Nicola; Vacchi, Andrea; Gennaro, Gisella; Uzunov, Nikolay

    2011-06-01

    Collimators are usually needed to image sources emitting X-rays that cannot be focused. Alternately, one may employ a Compton Camera (CC) and measure the direction of the incident X-ray by letting it interact with a thin solid, liquid or gaseous material (Tracker) and determine the scattering angle. With respect to collimated cameras, CCs allow higher gamma-ray efficiency in spite of lighter geometry, and may feature comparable spatial resolution. CCs are better when the X-ray energy is high and small setups are required. We review current applications of CCs to Gamma Ray Astronomy and Biomedical systems stressing advantages and drawbacks. As an example, we focus on a particular CC we are developing, which is designed to image small animals administered with marked pharmaceuticals, and assess the bio-distribution and targeting capability of these latter. This camera has to address some requirements: relatively high activity of the imaged objects; detection of gamma-rays of different energies that may range from 140 keV (Tc99m) to 511 keV; presence of gamma and beta radiation with energies up to 2 MeV in case of 188Re. The camera consists of a thin position-sensitive Silicon Drift Detector as Tracker, and a further downstream position-sensitive system employing scintillating crystals and a multi-anode photo-multiplier (Calorimeter). The choice of crystal, pixel size, and detector geometry has been driven by measurements and simulations with the tracking code GEANT4. Spatial resolution, efficiency and scope are discussed.

  16. Application of a new Raman microprobe spectrometer to nondestructive analysis of sulfate and other ions in individual phases in fluid inclusions in minerals

    USGS Publications Warehouse

    Rosasco, G.J.; Roedder, E.

    1979-01-01

    Rosasco et al. (1975), reported the first successful application of laser-excited Raman spectroscopy for the identification and nondestructive partial analysis of individual solid, liquid, and gaseous phases in selected fluid inclusions. We report here the results of the application of a new instrument, based on back-scattering, that eliminates many of the previous stringent sample limitations and hence greatly expands the range of applicability of Raman spectroscopy to fluid inclusions. Fluid inclusions in many porphyry copper deposits contain 5-10 ??m 'daughter' crystals thought to be anhydrite but too small for identification by the previous Raman technique. Using the new instrument, we have verified that such daughter crystals in quartz from Bingham, Utah, are anhydrite. They may form by leakage of hydrogen causing internal autooxidation of sulfide ion. Daughter crystals were also examined in apatite (Durango, Mexico) and emerald (Muzo, Colombia). Valid analyses of sulfur species in solution in small fluid inclusions from ore deposits would be valuable, but are generally impossible by conventional methods. We present a calibration procedure for analyses for SO42- in such inclusions from Bingham, Utah (12,000 ?? 4000 ppm) and Creede, Colo. (probably < 500 ppm). A fetid Brazilian quartz, originally thought to contain liquid H2S, is shown to contain only HS- in major amounts. ?? 1979.

  17. Magnetic-field-induced crossover from non-Fermi to Fermi liquid at the quantum critical point of YbCu5-xAux

    NASA Astrophysics Data System (ADS)

    Carretta, P.; Pasero, R.; Giovannini, M.; Baines, C.

    2009-01-01

    The temperature (T) dependence of the muon and C63u nuclear spin-lattice relaxation rates 1/T1 in YbCu4.4Au0.6 is reported over nearly four decades. It is shown that for T→0 1/T1 diverges following the behavior predicted by the self-consistent renormalization (SCR) theory for a ferromagnetic quantum critical point. On the other hand, the static uniform susceptibility χs is observed to diverge as T-2/3 and 1/T1T∝χs2 , a behavior which is not accounted for by SCR theory. The application of a magnetic field H is observed to induce a crossover to a Fermi-liquid behavior and for T→0 1/T1 is found to obey the scaling law 1/T1(H)=1/T1(0)[1+(μBH/kBT)2]-1 .

  18. BioRef: A versatile time-of-flight reflectometer for soft matter applications at Helmholtz-Zentrum Berlin

    SciTech Connect

    Strobl, M.; Kreuzer, M.; Steitz, R.; Rose, M.; Herrlich, H.; Mezei, F.; Grunze, M.; Dahint, R.

    2011-05-15

    BioRef is a versatile novel time-of-flight reflectometer featuring a sample environment for in situ infrared spectroscopy at the reactor neutron source BER II of the Helmholtz Zentrum Berlin fuer Materialien und Energie (HZB). After two years of design and construction phase the instrument has recently undergone commissioning and is now available for specular and off-specular neutron reflectivity measurements. BioRef is especially dedicated to the investigation of soft matter systems and studies at the solid-liquid interface. Due to flexible resolution modes and variable addressable wavelength bands that allow for focusing onto a selected scattering vector range, BioRef enables a broad range of surface and interface investigations and even kinetic studies with subsecond time resolution. The instrumental settings can be tailored to the specific requirements of a wide range of applications. The performance is demonstrated by several reference measurements, and the unique option of in situ on-board infrared spectroscopy is illustrated by the example of a phase transition study in a lipid multilayer film.

  19. Applicability of alkali activated slag-seeded Egyptian Sinai kaolin for the immobilization of 60Co radionuclide

    NASA Astrophysics Data System (ADS)

    El-Naggar, M. R.

    2014-04-01

    The present work was established to determine the applicability of local Egyptian kaolinite and blast furnace slag (BFS) as raw materials toward the synthesis of geopolymers and subsequent immobilization of cobalt-60, which is one of the most abundant radionuclides generated in radioactive waste streams in Egypt. XRF, XRD, FT-IR, and SEM techniques were used to characterize the local raw materials and their corresponding alkali activated products. Metakaolin (MK) was obtained by thermal treatment of Egyptian Sinai kaolin 750 °C/4 h. MK and five different BFS content (5, 10, 30, 50 and 80%) were used to synthesize geopolymeric matrices using an alkaline activator of Si-modulus = 1.35 at solid/liquid ratios of 0.8. Compressive strength tests were performed indicating that 50% BFS addition gave the highest values of compressive strength. The IAEA standard leaching tests of cobalt-60 from the solidified waste matrices were carried out. The effective diffusion coefficients of cobalt-60 radionuclides from the solidified waste matrices were calculated to be in the order of 10-14 cm2/s. Leaching of radionuclides was examined to be controlled by the wash-off mechanism with very acceptable values. These results gave encouragement that the tested Egyptian raw materials can be conveniently applied for the synthesis of geopolymers that can be used as a low-cost and high-efficiency materials for the immobilization of radioactive waste.

  20. Remote sensing in environmental police investigations: aerial platforms and an innovative application of thermography to detect several illegal activities.

    PubMed

    Lega, M; Ferrara, C; Persechino, G; Bishop, P

    2014-12-01

    Being able to identify the environmental crimes and the guilty parties is central to police investigations, and new technologies enable the authorities to do this faster and more accurately than ever before. In recent years, our research team has introduced the use of a range of aerial platforms and an innovative application of thermography to detect several illegal activities; for example, illegal sanitary sewer and storm-drain connections, illicit wastewater discharges, and other "anomalies" on surface waters can be easily identified using their thermal infrared signatures. It can also be used to detect illegal solid/liquid waste dumps or illicit air discharges. This paper introduces first results of a Thermal Pattern and Thermal Tracking approach that can be used to identify different phenomena and several pollutants. The aims of this paper were to introduce a fingerprint paradigm for environmental police investigations, defining several specific signatures (patterns) that permit the identification of an illicit/anomalous activity, and establish a procedure to use this information to find the correlation (tracking) between the crime and the culprit or the source and the target. PMID:25154683

  1. Instability of anthocyanin composition under different subculture conditions during long-term suspension cultures of Vitis vinifera L. var. Gamay Fréaux.

    PubMed

    Qu, Junge; Zhang, Wei; Yu, Xingju

    2011-11-01

    The instability of secondary metabolite production is a ubiquitous problem in plant cell culture. In order to understand the instability in plant cell culture, we investigated anthocyanin accumulation in suspension cultures of Vitis vinifera, as a model system, in our laboratory. Not only the anthocyanin contents but also its composition exhibited instability along with the long-term subculture. New methods were developed to indicate the instability of plant cell culture. Both the definition of instability coefficient (delta) and the application of factor scores were the first time in this field. To examine the effects of culture conditions on instability of anthocyanin biosynthesis, different subculture cycles and inoculum sizes had been investigated. Subculture cycle and inoculum size were both environmental cues driving the instability. Compared with subculture cycle, inoculum size was more effective in working on the instability of anthocyanin accumulation. Among all the conditions investigated in our study, (6.5 d, 2.00 g), (7 d, 2.00 g), (7.5 d, 2.00 g), (7 d, 1.60 g) and (7 d, 2.40 g), the condition of 7 d-subculture cycle together with 1.60 g-inoculum size was the best one to keep the stable production of anthocyanins. PMID:22393716

  2. Thermoelectric Properties of Au- Containing Type-I Clathrates Ba8AuxGa16-3xGe30+2x

    SciTech Connect

    Ye, Zuxin; Cho, Jung Young; Tessema, Misle M.; Salvador, James R.; Waldo, Richard A.; Yang, Jihui; Wang, Hsin; Cai, Wei; Kirkham, Melanie J; Yang, Jiong; Zhang, Wenqing

    2014-01-01

    Type I clathrates, with compositions based on Ba8Ga16Ge30, are a class of promising thermoelectric materials due to their intrinsically low thermal conductivity. It has been demonstrated previously that the thermoelectric performance can be improved by transition metal substitution of the framework atoms. In this study, the effects of Au substitution for Ga/Ge on thermal and electrical transport properties of type I clathrate compounds have been investigated. Polycrystalline samples with a large range of Au content have been synthesized using conventional solid state techniques with the actual compositions of resulting materials approximately following Zintl-Klemm rules. The charge carrier type changes from electrons (n) to holes (p) as the Au content increases. The Seebeck coefficient (S) and power factor (S2/ where is the electrical resistivity) were improved by Au substitution and the resulting overall thermoelectric properties were enhanced by Au substitution with a thermoelectric figure of merit ZT ~ 0.63 at temperature T = 740 K for the composition Ba8Au5.47Ge39.96. The results presented herein show that Au-containing type I clathrates are promising p-type thermoelectric materials for high temperature applications.

  3. L'application de l'appareil Suvaglingua de correction phonetique a l'enseignement de l'espagnol aux francophones (The Use of the Suvaglingua Synthesizer for Phonetic Correction in Spanish Courses for French Speakers)

    ERIC Educational Resources Information Center

    Sarmiento, Jose; And Others

    1974-01-01

    Describes the use of the verbo-tonal method of phonetic correction and the Suvaglingua synthesizer in Spanish courses at the International School of Interpreters at Mons, France. (Text is in French.) (PMP)

  4. Vers une méthode de réglage expérimentale des commandes PID floues : application aux systèmes électromécaniques

    NASA Astrophysics Data System (ADS)

    Maussion, P.; Hissel, D.

    1998-08-01

    Electrical and electromechanical systems have to satisfy to more and more constrained specifications. Therefore, non-linear control structures must be spread out. Among them, fuzzy logic control can be one interessant and performant alternative. The main handicap of this kind of stucture resides in the fact that the tuning parameters are very numerous. In this paper, we first propose an on-site tuning strategy of this set of parameters in the case of a fuzzy proportionnal-integrative controller based on the experimental designs methodology and on a limited number of pre-defined closed-loop experiments. Then, a complete set of predetermined parameters for a fuzzy proportionnal-integrative-derivative controller will be given. These parameters have been optimized on a specified benchmark according to an IAE criterion. They are calculated like the Ziegler-Nichols or Broïda methodology on conventional controllers; that is, using a single open-loop step response to obtain a model of a first-order plus delay transfert function. Validity limits for this method are provided. Les systèmes électriques ou électromécaniques doivent satisfaire à des spécifications de plus en plus contraignantes qui nécessitent la mise au point de structures de commande non linéaires. Parmi celles-ci, la commande par logique floue constitue une alternative intéressante et performante. Son principal handicap réside dans le nombre très important de paramètres à régler. Dans cet article, nous nous proposons de systématiser ces réglages dans deux cas de figure. Tout d'abord nous utiliserons la méthodologie des plans d'expérimentations pour effectuer un réglage sur site d'un contrôleur flou de type proportionnel-intégral. Ce réglage sera obtenu en ne réalisant qu'un nombre limité d'essais expérimentaux en boucle fermée avec des combinaisons prédéfinies des paramètres à régler. La combinaison optimale de ces paramètres au sens d'un critère de type IAE (Intégrale de la valeur Absolue de l'Erreur) sera déduite de l'exploitation des résultats des essais. Dans un deuxième temps, nous proposerons des réglages prédéfinis et optimisés (au sens du même critère) d'un contrôleur flou de type proportionnel-intégral-dérivé. Ces réglages préétablis ne nécessiteront qu'un seul essai d'identification du système à contrôler en boucle ouverte et peuvent donc se rapprocher des méthodologies classiques et éprouvées de réglage sur site que constituent les réglages de Ziegler-Nichols ou de Broïda pour des contrôleurs conventionnels. Dans cet article, les jeux de paramètres préétablis que nous fournirons seront valables pour des systèmes dont la réponse indicielle en boucle ouverte est modélisable sous la forme d'une fonction de transfert du premier ordre plus un retard pur. Les limites de validité de cette méthode seront précisées.

  5. Utilisation de la teledetection, des SIG et de l'intelligence artificielle pour determiner le niveau de susceptibilite aux mouvements de terrain: Application dans les Andes de la Bolivie

    NASA Astrophysics Data System (ADS)

    Peloquin, Stephane

    1999-11-01

    The socio-economic impact of mass movements for our society is getting more and more serious. The loss of lives and economic losses are now ten times greater than they were at the beginning of the decade. In the hope of reducing these impacts, it is essential to adopt a preventive policy that will encourage mapping of mass movement susceptibility level (MMSL) in critical zones. However, this task is complex and only experts using present techniques can provide satisfactory results. To make possible the production of these maps by a larger number of individuals, we have developed an expert system called EXPERIM that uses remote sensing data and geographic information systems to facilitate the complex tasks without requiring the user to be highly competent in this field of study. This thesis presents the results obtained from a complete strategy developed for a region surrounding Cochabamba, Bolivia. The operational expert system prototype will soon be integrated within the watershed management program directed by the local executing organisation PROMIC. The knowledge acquisition and its expression in concrete terms constitute the principal axis of this research, while the results obtained are the heart of the EXPERIM expert system. These strategic steps aim to establish a knowledge base of data and rules that describe field conditions for each MMSL. We have been able to extract this information by using binary discriminant analysis of a MMSL map produced by an expert for a pilot zone called Cuenca Taquina, which is geoecologically representative of the 38 neighbouring watersheds. Using this technique, we were able to establish a sensitivity model that recreates the expert's map with a success rate of 89% and 78% when two or three MMS levels are used. Based on a detailed analysis of the susceptibility model it was evident that stability conditions are the result of the topographic, geologic and geomorphologic environments. The level of susceptibility was found to be independent of the vegetation condition. In order to apply the model to the surrounding watersheds, we integrated remotely sensed data within the spatial database to map the presence/absence of five essential geoecological units required by the susceptibility model. This was done using a hierarchical classification method. Three sensors were evaluated: Landsat, SPOT and RADARSAT. In the elaboration of this specific step, we evaluated the most efficient spectral band combinations within each image and between images for each of the five geoecological units. For each of the land cover types, the analysis shows that LANDSAT constitutes the most powerful sensor to map these units and that image fusion does not provide significantly better results when compared to the extra amount of work that this requires. Using remote sensing data instead of field data or airphotograph interpretation in watersheds where only topographic data are available decreases the level of accuracy by less than 10%.

  6. Teeth and bones: applications of surface science to dental materials and related biomaterials

    NASA Astrophysics Data System (ADS)

    Jones, F. H.

    2001-05-01

    Recent years have seen a considerable upsurge in publications concerning the surface structure and chemistry of materials with biological or biomedical applications. Within the body, gas-solid interactions become relatively less significant and solid-liquid or solid-solid interfaces dominate, providing new challenges for the surface scientist. The current paper aims to provide a timely review of the use of surface analysis and modification techniques within the biomaterials field. A broad overview of applications in a number of related areas is given with particular attention focusing on those materials commonly encountered in dentistry and oral or maxillofacial implantology. Several specific issues of current interest are discussed. The interaction between synthetic and natural solids, both in the oral environment and elsewhere in the body is important in terms of adhesion, related stresses and strains and ultimately the longevity of a dental restoration, biomedical implant, or indeed the surrounding tissue. Exposure to body fluids, of course, can also affect stability, leading to the degradation or corrosion of materials within the body. Whilst this could potentially be harmful, e.g., if cytotoxic elements are released, it may alternatively provide a route to the preferential release of beneficial substances. Furthermore, in some cases, the controlled disintegration of a biomaterial is desirable, allowing the removal of an implant, e.g., without the need for further surgery. The presence of cells in the immediate bioenvironment additionally complicates the situation. A considerable amount of current research activity is targeted at the development of coatings or surface treatments to encourage tissue growth. If this is to be achieved by stimulating enhanced cell productivity, determination of the relationship between cell function and surface composition is essential.

  7. A novel application of an anaerobic membrane process in wastewater treatment.

    PubMed

    You, H S; Tseng, C C; Peng, M J; Chang, S H; Chen, Y C; Peng, S H

    2005-01-01

    The applications of membrane processes in anaerobic biological wastewater treatment still have some limitations due to severe membrane scaling and fouling, although they have been proven to achieve superior COD removal and biomass retention. An innovative anaerobic membrane process for wastewater treatment was conducted to control the membrane scaling problems. The process comprises an anaerobic reactor, an aerobic reactor, and a membrane separation tank. Anaerobic sludge from a full-scale UASB reactor treating food wastewater was inoculated to anaerobic and aerobic reactor to purify synthetic wastewater consisting of glucose and sodium acetate. The anaerobic reactor was operated in a sludge bed type without three-phase separator. The aerobic reactor can eliminate residual organics from the anaerobic reactor effluent using facultative microorganisms. To provide solid-liquid separation, hollow fiber ultrafiltration module was submerged in the separation tank. The results clearly show that the anaerobic membrane process combined methanogenic and aerobic COD reduction is a stable system. No fatal scaling was found after two months of operation even without chemical cleaning for the membrane. It was also found that inorganic precipitates formed in the aerobic reactor were reduced due to CO2 stripping in aerobic reactor. Another important finding was that the inorganic precipitates were entrapped into facultative aerobes floc. The ash/SS ratio of aerobes floc increased from 0.17 to 0.55 after 50 days of operation, which confirms this phenomenon. Based on our investigation, the new process can control scaling effectively to extend the membrane application in anaerobic treatment. PMID:16003960

  8. Applications and Properties of Ionic Liquid- Based Gels and Soft Solid Composites

    NASA Astrophysics Data System (ADS)

    Voss, Bret Alan McGinness

    2011-12-01

    Solid-liquid composites (gels) have a combination of properties that afford new material applications in which high solute diffusion is desirable. These composites have a soft-solid mechanical integrity and will not flow under gravity, but entrain a liquid matrix (i.e. 60-98 mass %) which allows for high diffusion and high reactivity. Room temperature ionic liquid (RTILs) are molten organic salts with a melting point below room temperature and negligible vapor pressure. If the RTILs are used as the liquid component of a gel, then the gel matrix will not evaporate (unlike other organic solvents) and may be used for long term applications. This thesis research applies RTIL gels for two new applications; carbon dioxide/nitrogen separation and chemical warfare agent (CWA) barrier and decontamination. Separating CO2 from the flue gas of coal and gas fired power-plants is an increasingly economically and environmentally important gas separation. In this first study, RTIL gels are cast in a supported membrane and gas permeability and ideal selectivity are measured. The RTIL matrix has an inherent affinity for CO2 and provides a high diffusion, hence high permeability (i.e. 500-700 barrer). The solidifying component is a low molecular-weight organic gelator (LMOG) which through physical bonding interactions (i.e. hydrogen bonding, pi-pi stacking and van der Walls forces) forms an entangled network which provides mechanical stability (i.e. increase trans-membrane pressure required to expel selective material from the support). In these studies two LMOGs and five RTILs are used to make supported gel membranes and determine gas permeability and temperature dependent trends. The second application for RTIL gels is a decontaminating barrier for CWAs and toxic industrial compounds (TICs). In these studies a layer of RTIL gel is applied on top of a substrate contaminated with a CWA simulant (i.e. chloroethylethylsulfide, CEES). The gel performs well as a barrier, preventing CEES

  9. Optimizing the electric field around solid and core-shell alloy nanostructures for near-field applications.

    PubMed

    Montaño-Priede, Luis; Peña-Rodríguez, Ovidio; Rivera, Antonio; Guerrero-Martínez, Andrés; Pal, Umapada

    2016-08-21

    The near electric field enhancement around plasmonic nanoparticles (NPs) is very important for applications like surface enhanced spectroscopies, plasmonic dye-sensitized solar cells and plasmon-enhanced OLEDs, where the interactions occur close to the surface of the NPs. In this work we have calculated the near-field enhancement around solid and core-shell alloy NPs as a function of their geometrical parameters and composition. We have found that the field enhancement is lower in the AuxAg1-x alloys with respect to pure Ag NPs, but it is still high enough for most near-field applications. The higher order modes have a stronger influence over the near-field due to a sharper spatial decay of the near electric field with the increase of the order of multipolar modes. For the same reason, in AuxAg1-x@SiO2 core-shell structures, the quadrupolar mode is dominant around the core, whereas the dipolar mode is predominant around the shell. The LSPR modes can have different behaviours in the near- and the far-field, particularly for larger particles with high Ag contents, which indicates that caution must be exercised for designing plasmonic nanostructures for near-field applications, as the variations of the LSPR in the near-field cannot be inferred from those observed in the far-field. These results have important implications for the application of gold-silver alloy NPs in surface enhanced spectroscopies and in the fabrication of plasmon-based optoelectronic devices, like dye-sensitized solar cells and plasmon-enhanced organic light-emitting diodes. PMID:27451969

  10. Optimizing the electric field around solid and core-shell alloy nanostructures for near-field applications

    NASA Astrophysics Data System (ADS)

    Montaño-Priede, Luis; Peña-Rodríguez, Ovidio; Rivera, Antonio; Guerrero-Martínez, Andrés; Pal, Umapada

    2016-08-01

    The near electric field enhancement around plasmonic nanoparticles (NPs) is very important for applications like surface enhanced spectroscopies, plasmonic dye-sensitized solar cells and plasmon-enhanced OLEDs, where the interactions occur close to the surface of the NPs. In this work we have calculated the near-field enhancement around solid and core-shell alloy NPs as a function of their geometrical parameters and composition. We have found that the field enhancement is lower in the AuxAg1-x alloys with respect to pure Ag NPs, but it is still high enough for most near-field applications. The higher order modes have a stronger influence over the near-field due to a sharper spatial decay of the near electric field with the increase of the order of multipolar modes. For the same reason, in AuxAg1-x@SiO2 core-shell structures, the quadrupolar mode is dominant around the core, whereas the dipolar mode is predominant around the shell. The LSPR modes can have different behaviours in the near- and the far-field, particularly for larger particles with high Ag contents, which indicates that caution must be exercised for designing plasmonic nanostructures for near-field applications, as the variations of the LSPR in the near-field cannot be inferred from those observed in the far-field. These results have important implications for the application of gold-silver alloy NPs in surface enhanced spectroscopies and in the fabrication of plasmon-based optoelectronic devices, like dye-sensitized solar cells and plasmon-enhanced organic light-emitting diodes.

  11. Ampleur et impact des évènements indésirables graves liés aux soins: étude d'incidence dans un hôpital du Centre-Est tunisien

    PubMed Central

    Bouafia, Nabiha; Bougmiza, Iheb; Bahri, Fathi; Letaief, Mondher; Astagneau, Pascal; Njah, Mansour

    2013-01-01

    Introduction La prévention des événements indésirables représente une priorité de santé du fait de leur fréquence et de leur gravité potentielle. Ce travail a été mené afin d'avoir un diagnostic de la situation épidémiologique relative aux événements indésirables survenant dans notre hôpital. Méthodes Une étude prospective a été menée auprès de tous les patients qui ont été hospitalisés au CHU Farhat Hached - Sousse (Tunisie) sur une période d'un mois dans quatorze services de l'hôpital. La détection d'évènement indésirable grave (EIG) était basée sur les critères adoptés dans différentes études. Les tests T et Chi 2 ont été utilisés pour identifier les facteurs contribuant à l'apparition d'évènements indésirables. Résultats Au total, 162 EIG ont été identifiés pendant la période. 45% de ces évènements étaient des infections nosocomiales. Ces EIG ont eu comme conséquences un décès chez 9,2% des patients, la mise en jeu du pronostic vital de 26% des patients et la prolongation de la durée de séjour chez 61,7% d'entre eux. L'admission dans des circonstances particulières et l'exposition à des soins invasifs étaient identifiés comme des facteurs de risque potentiels EIG. Conclusion Le renforcement de la stratégie de gestion des risques sanitaires en ciblant préférentiellement le risque infectieux constitue une étape fondamentale dans l'amélioration de la sécurité des patients au sein de notre établissement de santé. PMID:24711868

  12. Scaling of three-dimensional interconnect technology incorporating low temperature bonds to pitches of 10 µm for infrared focal plane array applications

    NASA Astrophysics Data System (ADS)

    Temple, Dorota S.; Lueck, Matthew R.; Malta, Dean; Vick, Erik P.

    2015-03-01

    This paper focuses on the application of low temperature bonding to the fabrication of three-dimensional (3D) massively parallel signal processors for high performance infrared imagers. We review two generations of the 3D heterogeneous integration process. The first generation process, compatible with pixel sizes in the 20 to 30 µm range, relies on low temperature epoxy bonding that is followed by the formation of copper-filled through-silicon vias (TSVs). The second generation process, scalable to pixel sizes of 10 µm and smaller, employs solid-liquid diffusion bonding of copper-tin to copper at 250 °C the bonding follows TSV fabrication. To demonstrate the second generation process, we fabricated 3D test vehicles in the form of 640 × 512 arrays of vertical interconnects composed of TSVs and metal-metal bonds on a 10 µm pitch. We characterized electrical conductivity of the interconnects, the isolation resistance between the interconnects, and the operability and yield of the arrays. The successful demonstration of the interconnect technology paves the way to a functional demonstration of 3D signal processors in infrared imagers with 10 µm pixels.

  13. Experimental studies of contact angle hysteresis phenomena on polymer surfaces – Toward the understanding and control of wettability for different applications.

    PubMed

    Grundke, K; Pöschel, K; Synytska, A; Frenzel, R; Drechsler, A; Nitschke, M; Cordeiro, A L; Uhlmann, P; Welzel, P B

    2015-08-01

    Contact angle hysteresis phenomena on polymer surfaces have been studied by contact angle measurements using sessile liquid droplets and captive air bubbles in conjunction with a drop shape method known as Axisymmetric Drop Shape Analysis - Profile (ADSA-P). In addition, commercially available sessile drop goniometer techniques were used. The polymer surfaces were characterized with respect to their surface structure (morphology, roughness, swelling) and surface chemistry (elemental surface composition, acid-base characteristics) by scanning electron microscopy (SEM), scanning force microscopy (SFM), ellipsometry, X-ray photoelectron spectroscopy (XPS) and streaming potential measurements. Heterogeneous polymer surfaces with controlled roughness and chemical composition were prepared by different routes using plasma etching and subsequent dip coating or grafting of polymer brushes, anodic oxidation of aluminium substrates coated with thin polymer films, deposition techniques to create regular patterned and rough fractal surfaces from core-shell particles, and block copolymers. To reveal the effects of swelling and reorientation at the solid/liquid interface contact angle hysteresis phenomena on polyimide surfaces, cellulose membranes, and thermo-responsive hydrogels have been studied. The effect of different solutes in the liquid (electrolytes, surfactants) and their impact on contact angle hysteresis were characterized for solid polymers without and with ionizable functional surface groups in aqueous electrolyte solutions of different ion concentrations and pH and for photoresist surfaces in cationic aqueous surfactant solutions. The work is an attempt toward the understanding of contact angle hysteresis phenomena on polymer surfaces aimed at the control of wettability for different applications. PMID:25488284

  14. Carbon-Based Wear Coatings: Properties and Applications

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    2003-01-01

    The technical function of numerous engineering systems - such as vehicles, machines, and instruments - depends on the processes of motion and on the surface systems. Many processes in nature and technology depend on the motion and dynamic behavior of solids, liquids, and gases. Smart surface systems are essential because of the recent technological push toward higher speeds, loads, and operating temperatures; longer life; lighter weight and smaller size (including nanotechnology); and harsh environments in mechanical, mechatronic, and biomechanical systems. If proper attention is not given to surface systems, then vehicles, machines, instruments, and other technical systems could have short lives, consume excessive energy, experience breakdowns, result in liabilities, and fail to accomplish their missions. Surface systems strongly affect our national economy and our lifestyles. At the NASA Glenn Research Center, we believe that proper attention to surface systems, especially in education, research, and application, could lead to economic savings of between 1.3 and 1.6 percent of the gross domestic product. Wear coatings and surface systems continue to experience rapid growth as new coating and surface engineering technologies are discovered, more cost-effective coating and surface engineering solutions are developed, and marketers aggressively pursue, uncover, and exploit new applications for engineered surface systems in cutting tools and wear components. Wear coatings and smart surface systems have been used widely in industrial, consumer, automotive, aerospace, and biomedical applications. This presentation expresses the author's views of and insights into smart surface systems in wear coatings. A revolution is taking place in carbon science and technology. Diamond, an allotrope of carbon, joins graphite, fullerenes, and nanotubes as its major pure carbon structures. It has a unique combination of extreme properties: hardness and abrasion resistance; adhesion

  15. Coupleurs fibres - metasurfaces aux frequences THz

    NASA Astrophysics Data System (ADS)

    Girard, Martin

    Metamaterials are a class of arficial materials where the electromagnetic properties can be tailored during the design process. Currently demonstrated properties are varied, ranging from frequency filters to enhancement of quentum effects such as photon spin Hall effect. While these materials are mastered from a theoretical point of view, their fabrication is much more complicated. It is generally accepted that metamaterial elements must be under the effective medium limit (Lambda < lambda/10). Moreover, assembly of a 3D periodical system becomes much more complicated for small elements. For this reason, metamaterials are usually printed in 2D, on a surface, which are called metasurfaces. Generally, these are produced for the THz frequencies (˜ 1012 Hz) or lower to have a large wavelength and thus easy fabrication. Working at THz frequencies also carries additional problems. Absorption in traditional optical mediums is typically large (for exemple, BK7 glass has losses of 20 dB / cm) and powers supplied by THz sources are generally weak ( 100 muW for a THz-TDS standard source). Metasurfaces can thus play an important role by replacing traditional mediums. Moreover, we can use the resonant properties of metamaterials to produce sensors and other devices. Currently, the metasurfaces are used in conjuction with a free-space beam instead of a typical waveguide, which may be problematic when implementing devices. A simple solution to this problem is to use the metamaterial as a standard coupler by placing a waveguide above the metasurface. As stated before, we generally consider metasurfaces as effective mediums, where the permittivity is insensitive to the angle of the incident beam. However, a large amount of publications on this subject shows that this is not respected. This can have a huge impact on properties of a coupler based on such a material. First, modelisation is not a simple 2D mode calculation with a simple expression for permittivity. Second, contra-directional coupling becomes permitted due to wavevector becoming close to the periodicity. This work shows modelisation of such a fiber-metasurface coupler while taking account of these problems, with two publications on the subject. The first article modelises the coupler using a 400 mum diameter subwavelength step-index fiber coupled to a metasurface made of SRR on a 700 mum thick fused silica substrate. Frequencies are around 300 GHz (lambda = 1000 mum). We obtain some interesting results. First, the system shows a large number of fine resonances (˜ 1.5 GHz) instead of a single large resonance which would be typically seen on such a metasurface. These are constitued of a both a SRR-bound field and a propagative substrate mode. Second, these resonances are strongly influenced by the fiber-metasurface distance. Third, the spectral position can be easily calculated using a band diagram since they are located at Van Hove singularities. The second article treats of a paper sensor based on such a device. The geometry used is the same as in the first article, except for two differences. First, the substrate thickness has been reduced to 320 mum to lower the amount of substrate modes available. Second, a paper layer was added underneath the substrate. Since the resonances are a mixture of SRR-bound and substrate modes, resonance parameters change with paper properties. The spectral position can be related to paper thickness and real part of the permittivity while the reflectance amplitude is related to the imaginary part of the permittivity. A Clausius-Mossotti model is used to link the imaginary part of epsilon to the water content. Assuming negligible losses for the fiber and substrate, we obtain limit of detections of 10 mum of paper thickness change and 0.02 % V/V for the water content.

  16. Influence of hydro-climatic conditions, soil type, and application matrix on potential vadose zone export of PPCPs

    NASA Astrophysics Data System (ADS)

    Gall, H. E.; Rao, P.; O'Connor, G.

    2013-12-01

    The land-application of biosolids and animal manure to agricultural fields has the potential to negatively impact the quality of nearby surface and subsurface water due to the presence of emerging contaminants in these residuals. We investigated the extent to which the vadose zone acts as a hydrologic and biogeochemical filter of two emerging contaminants, Triclosan (TCS) and estrone (E1) using a coupled source zone and vadose zone modeling approach. Monte Carlo simulations were run for a year following residual applications to explore the following research questions: (1) how does the application matrix (e.g., de-watered solids, liquid lagoon effluent, etc.) affect PPCP mass fluxes?; (2) how do hydro-climatic conditions and soil type affect PPCP mass fluxes?; (3) what role does the presence of macropore pathways play in PPCP export from the vadose zone; and (4) does the long-term, repeated application of residuals affect the ability of the vadose zone to act as an effective biogeochemical filter? The simulations were conducted for a sub-tropical climate with sand (e.g., Florida) and a humid climate with a silty clay loam (e.g., Midwestern United States). Simulation results suggest that the potential mobility of emerging contaminants increases linearly with increasing fraction applied to the mobile phase of the source zone (i.e., higher PPCP mass fraction in the dissolved phase during application). Following a single application, the total amount of PPCP mass exported from the source zone over the course of a year can be as high as 70% in a sub-tropical climate with sand soil. However, these types of soils do not have macropore flow pathways and the annual PPCP mass exported from the vadose zone is less than 1% of the mass applied. The higher organic carbon content in a silty clay loam reduces the amount of PPCP mass released from the source zone to less than 5% of the mass applied. In the presence of macropore pathways, the silty clay loam's vadose zone acts as a

  17. The application of Cold Atmospheric Plasma (CAP) for the sterilisation of spacecraft materials

    NASA Astrophysics Data System (ADS)

    Rettberg, Petra; Barczyk, Simon; Morfill, Gregor; Thomas, Hubertus; Satoshi Shimizu, .; Shimizu, Tetsuji; Klaempfl, Tobias

    2012-07-01

    Plasma, oft called the fourth state of matter after solid, liquid and gas, is defined by its ionized state. Ionization can be induced by different means, such as a strong electromagnetic field applied with a microwave generator. The concentration and composition of reactive atoms and molecules produced in Cold Atmospheric Plasma (CAP) depends on the gases used, the gas flow, the power applied, the humidity level etc.. In medicine, low-temperature plasma is already used for the sterilization of surgical instruments, implants and packaging materials as plasma works at the atomic level and is able to reach all surfaces, even the interior of small hollow items like needles. Its ability to sterilise is due to the generation of biologically active bactericidal agents, such as free radicals and UV radiation. In the project PLASMA-DECON (DLR/BMWi support code 50JR1005) a prototype of a device for sterilising spacecraft material and components was built based on the surface micro-discharge (SMD) plasma technology. The produced plasma species are directed into a closed chamber which contains the parts that need to be sterilised. To test the inactivation efficiency of this new device bacterial spores were used as model organisms because in the COSPAR Planetary Protection Policy all bioburden constraints are defined with respect to the number of spores (and other heat-tolerant aerobic microorganisms). Spores from different Bacillus species and strains, i.e. wildtype strains from culture collections and isolates from spacecraft assembly cleanrooms, were dried on three different spacecraft relevant materials and exposed to CAP. The specificity, linearity, precision, and effective range of the device was investigated. From the results obtained it can be concluded that the application of CAP proved to be a suitable method for bioburden reduction / sterilisation in the frame of planetary protection measures and the design of a larger plasma device is planned in the future.

  18. Competitive lipase-catalyzed ester hydrolysis and ammoniolysis in organic solvents; equilibrium model of a solid-liquid-vapor system.

    PubMed

    Litjens, M J; Sha, M; Straathof, A J; Jongejan, J A; Heijnen, J J

    1999-11-01

    Enzymatic ester hydrolysis and ammoniolysis were performed as competitive reactions in methyl isobutyl ketone without a separate aqueous phase. The reaction system contained solid ammonium bicarbonate, which dissolved as water, ammonia, and carbon dioxide. During the reaction an organic liquid phase, a vapor phase, and at least one solid phase are present. The overall equilibrium composition of this multiphase system is a complex function of the reaction equilibria and several phase equilibria. To gain a quantitative understanding of this system a mathematical model was developed and evaluated. The model is based on the mass balances for a closed batch system and straightforward relations for the reaction equilibria and the solubility equilibria of ammonium bicarbonate, the fatty acid ammonium salt, water, ammonia, and carbon dioxide. For butyl butyrate as a model ester and Candida antarctica lipase B as the biocatalyst this equilibrium model describes the experiments satisfactorily. The model predicts that high equilibrium yields of butyric acid can be achieved only in the absence of ammoniolysis or in the presence of a separate water phase. However, high yields of butyramide should be possible if the water concentration is fixed at a low level and a more suited source of ammonia is applied. PMID:10486134

  19. A study of the solid-liquid interface in cobalt base alloy (Stellite) coatings deposited by fusion welding (TIG)

    SciTech Connect

    Molleda, F. . E-mail: fmolleda@etsin.upm.es; Mora, J.; Molleda, F.J.; Mora, E.; Carrillo, E.; Mellor, B.G.

    2006-12-15

    Microstructural features present at the interface between a weld deposited Stellite 6 hard facing and an austenitic stainless steel substrate are described. Elemental X-ray maps indicate that diffusion of carbon from the liquid Stellite to the austenitic stainless steel takes place along grain boundaries resulting in the formation of chromium carbide 'arms' that penetrate along the austenite grain boundaries in the interfacial region.

  20. Trapped Melt in IIIAB Irons: Solid/Liquid Elemental Partitioning During the Fractionation of the IIIAB Magma

    NASA Technical Reports Server (NTRS)

    Wasson, John T.

    1999-01-01

    Group IIIAB, the largest iron-meteorite group, shows compositional trends (including a three-order-of-magnitude It concentration range) indicating that it formed by fractional crystallization of a metallic magma. Because about 200 irons are available, and all degrees of crystallization are well represented, IIIAB offers an excellent set of samples for the study of crystallization at all depths of the asteroidal core. On log-log Ir-Au, and Ir-As diagrams IIIAB forms a broad band; the breadth represents real meteorite-to-meteorite variations, far outside experimental or sampling uncertainties. A successful model must explain the width of this band; I suggest that it mainly resulted from the trapping of parental magma within the crystallizing solid. Because S is essentially insoluble in metal, the abundance of FeS is a measure of the fraction of trapped liquid. The trapped-melt model is supported by the observation that irons having higher S contents plot closer to the inferred composition of the magmatic parental liquid. The lowest S values are found in the irons occupying the left envelope of the IIIAB Ir-Au or Ir-As compositional fields, thus it is this set of irons that should be interpreted as the solid products of a fractionating magma. This simplifies the modeling of the crystallization process and allows inferences regarding the distribution ratios for other elements in the evolved IIIAB system. The large (multiton) Cape York irons show wide variations in their trapped-melt fractions; their compositions seem best understood in terms of a low initial S content of the IIIAB magma, about 20 mg/g. The inferred initial IIIAB distribution coefficient for Ir, 4.6, is much higher than published values based on laboratory studies of low-S systems; I suggest that low-S (and low-P) partition-ratio measurements tend to err in the direction of unity. In IIIAB distribution coefficients for Au, As, and Ni were still < 1 when the most evolved IIIAB irons formed, another indication of a low initial S content.

  1. Non-destructive monitoring of microbial biofilms at solid-liquid interfaces using on-line devices

    SciTech Connect

    Nivens, D.E. . Dept. of Chemistry Tennessee Univ., Knoxville, TN . Inst. for Applied Microbiology); Chambers, J.Q. . Dept. of Chemistry); White, D.C. . Inst. for Applied Microbiology Tennessee Univ., Knoxville, TN . Dept. of Microbiology Oak Ridge National Lab., TN )

    1990-01-01

    Corrosion, biofouling, and related problems have been an impetus for investigating interactions between microorganisms and solid surfaces. In recent years, a number of studies have been performed to assess the damages caused by microbial influenced corrosion (MIC). In a number of these studies, electrochemical techniques have monitored the performance of metal surfaces exposed to bacteria. However, most of these methods can only indirectly detect the presence of biofilms. In this paper, two non-destructive on-line monitoring devices, attenuated total reflection Fourier transform infrared spectroscopy (ATR-FT/IR) and the quartz crystal microbalance (QCM) were used to directly monitor biofilm formation. These devices have been developed to study the initial fouling process and subsequent biofilm development and not merely the effects of the living film on the host material. The ATR-FT/IR technique provides information about biomass, exopolymer production, and the nutritional status of microbial biofilms. The QCM provides a direct measure of biomass. ATR-FT/IR and QCM detect 10{sup 6} and 10{sup 4} Caulobacter crescentus cells/cm{sup 2}, respectively. Both techniques can be coupled with electrochemical methods for deeper insight into mechanisms of MIC. 20 refs., 2 figs.

  2. Experimental study on the determination of the shear-wave reflection coefficient at the solid-liquid interface

    NASA Astrophysics Data System (ADS)

    Franco, Ediguer E.; Adamowski, Julio C.; Buiochi, Flávio

    2012-05-01

    This work implements the ultrasonic shear-wave reflectance method for viscosity measurements. A modeconversion device was used for the dynamic viscosity measurement of mineral oil, SAE 40 automotive oil and glycerin samples at room temperature and 1 MHz. A novel signals processing technique that calculates the reflection coefficient magnitude in a frequency band, instead of a single frequency, was employed, showing an important improvement on the measurement accuracy.

  3. Superhydrophobic Photosensitizers. Mechanistic Studies of 1O2 Generation in the Plastron and Solid/Liquid Droplet Interface

    PubMed Central

    Aebisher, David; Bartusik, Dorota; Liu, Yang; Zhao, Yuanyuan; Barahman, Mark; Xu, QianFeng; Lyons, Alan M.; Greer, Alexander

    2014-01-01

    We describe here a physical-organic study of the first triphasic superhydrophobic sensitizer for photooxidations in water droplets. Control of synthetic parameters enables the mechanistic study of “borderline” two- and three-phase superhydrophobic sensitizer surfaces where 1O2 is generated in compartments that are wetted, partially wetted, or remain dry in the plastron (i.e., air layer beneath the droplet). The superhydrophobic surface is synthesized by partially embedding silicon phthalocyanine (Pc) sensitizing particles to specific locations on polydimethylsiloxane (PDMS) posts printed in a square array (1 mm tall posts on 0.5 mm pitch). In the presence of red light and oxygen, singlet oxygen is formed on the superhydrophobic surface and reacts with 9,10-anthracene dipropionate dianion (1) within a freestanding water droplet to produce an endoperoxide in 54–72% yields. Control of the 1O2 chemistry was achieved by the synthesis of superhydrophobic surfaces enriched with Pc particles either at the PDMS end-tips or at PDMS post bases. Much of the 1O2 that reacts with anthracene 1 in the droplets was generated by the sensitizer “wetted” at the Pc particle/water droplet interface and gave the highest endoperoxide yields. About 20% of the 1O2 can be introduced into the droplet from the plastron. The results indicate that the superhydrophobic sensitizer surface offers a unique system to study 1O2 transfer routes where a balance of gas and liquid contributions of 1O2 is tunable within the same superhydrophobic surface. PMID:24295210

  4. Exceptionally Slow Movement of Gold Nanoparticles at a Solid/Liquid Interface Investigated by Scanning Transmission Electron Microscopy.

    PubMed

    Verch, Andreas; Pfaff, Marina; de Jonge, Niels

    2015-06-30

    Gold nanoparticles were observed to move at a liquid/solid interface 3 orders of magnitude slower than expected for the movement in a bulk liquid by Brownian motion. The nanoscale movement was studied with scanning transmission electron microscopy (STEM) using a liquid enclosure consisting of microchips with silicon nitride windows. The experiments involved a variation of the electron dose, the coating of the nanoparticles, the surface charge of the enclosing membrane, the viscosity, and the liquid thickness. The observed slow movement was not a result of hydrodynamic hindrance near a wall but instead explained by the presence of a layer of ordered liquid exhibiting a viscosity 5 orders of magnitude larger than a bulk liquid. The increased viscosity presumably led to a dramatic slowdown of the movement. The layer was formed as a result of the surface charge of the silicon nitride windows. The exceptionally slow motion is a crucial aspect of electron microscopy of specimens in liquid, enabling a direct observation of the movement and agglomeration of nanoscale objects in liquid. PMID:26050969

  5. Transfers of iodine in the soil-plant-air system: Solid-liquid partitioning, migration, plant uptake adn volatilization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Human exposure to soil iodine depends upon the partitioning of the iodine into the, mobile, liquid and gaseous soil phases. From the liquid phase, iodine can be transported into surface- and ground-waters, plant roots, and, consequently, into the human diet. From the gaseous phase, iodine can be tra...

  6. Direct observation of ionic structure at solid-liquid interfaces: a deep look into the Stern Layer

    PubMed Central

    Siretanu, Igor; Ebeling, Daniel; Andersson, Martin P.; Stipp, S. L. Svane; Philipse, Albert; Stuart, Martien Cohen; van den Ende, Dirk; Mugele, Frieder

    2014-01-01

    The distribution of ions and charge at solid-water interfaces plays an essential role in a wide range of processes in biology, geology and technology. While theoretical models of the solid-electrolyte interface date back to the early 20th century, a detailed picture of the structure of the electric double layer has remained elusive, largely because of experimental techniques have not allowed direct observation of the behaviour of ions, i.e. with subnanometer resolution. We have made use of recent advances in high-resolution Atomic Force Microscopy to reveal, with atomic level precision, the ordered adsorption of the mono- and divalent ions that are common in natural environments to heterogeneous gibbsite/silica surfaces in contact with aqueous electrolytes. Complemented by density functional theory, our experiments produce a detailed picture of the formation of surface phases by templated adsorption of cations, anions and water, stabilized by hydrogen bonding. PMID:24850566

  7. Resolving Non-Specific and Specific Adhesive Interactions of Catechols at Solid/Liquid Interfaces at the Molecular Scale.

    PubMed

    Utzig, Thomas; Stock, Philipp; Valtiner, Markus

    2016-08-01

    The adhesive system of mussels evolved into a powerful and adaptive system with affinity to a wide range of surfaces. It is widely known that thereby 3,4-dihydroxyphenylalanine (Dopa) plays a central role. However underlying binding energies remain unknown at the single molecular scale. Here, we use single-molecule force spectroscopy to estimate binding energies of single catechols with a large range of opposing chemical functionalities. Our data demonstrate significant interactions of Dopa with all functionalities, yet most interactions fall within the medium-strong range of 10-20 kB T. Only bidentate binding to TiO2 surfaces exhibits a higher binding energy of 29 kB T. Our data also demonstrate at the single-molecule level that oxidized Dopa and amines exhibit interaction energies in the range of covalent bonds, confirming the important role of Dopa for cross-linking in the bulk mussel adhesive. We anticipate that our approach and data will further advance the understanding of biologic and technologic adhesives. PMID:27374053

  8. A Binary Solid-Liquid Phase Diagram Experiment Including Determination of Purity, Enthalpy of Fusion and True Melting Point.

    ERIC Educational Resources Information Center

    Meyer, Edwin F.; Meyer, Joseph A.

    1980-01-01

    Describes an experiment as an alternative to undergraduate experiments limited to high temperature metal systems or lower temperature systems involving objectionable or unstable materials. Lists six advantages of the experiment. (Author/JN)

  9. Oligo(p-phenylenevinylene)-peptide conjugates: synthesis and self-assembly in solution and at the solid-liquid interface.

    PubMed

    Matmour, Rachid; De Cat, Inge; George, Subi J; Adriaens, Wencke; Leclère, Philippe; Bomans, Paul H H; Sommerdijk, Nico A J M; Gielen, Jeroen C; Christianen, Peter C M; Heldens, Jeroen T; van Hest, Jan C M; Löwik, Dennis W P M; De Feyter, Steven; Meijer, E W; Schenning, Albertus P H J

    2008-11-01

    Two oligo(p-phenylenevinylene)-peptide hybrid amphiphiles have been synthesized using solid- and liquid-phase strategies. The amphiliphiles are composed of a pi-conjugated oligo(p-phenylenevinylene) trimer (OPV) which is coupled at either a glycinyl-alanyl-glycinyl-alanyl-glycine (GAGAG) silk-inspired beta-sheet or a glycinyl-alanyl-asparagyl-prolyl-asparagy-alanyl-alanyl-glycine (GANPNAAG) beta-turn forming oligopeptide sequence. The solid-phase strategy enables one to use longer peptides if strong acidic conditions are avoided, whereas the solution-phase coupling gives better yields. The study of the two-dimensional (2D) self-assembly of OPV-GAGAG by scanning tunneling microscopy (STM) at the submolecular level demonstrated the formation of bilayers in which the molecules are lying antiparallel in a beta-sheet conformation. In the case of OPV-GANPNAAG self-assembled monolayers could not be observed. Absorption, fluorescence, and circular dichroism studies showed that OPV-GAGAG and OPV-GANPNAAG are aggregated in a variety of organic solvents. In water cryogenic temperature transmission electron microscopy (cryo-TEM), atomic force microscopy (AFM), light scattering, and optical studies reveal that self-assembled nanofibers are formed in which the helical organization of the OPV segments is dictated by the peptide sequence. PMID:18847199

  10. Dispersive solid-liquid phase microextraction based on nanomagnetic Preyssler heteropolyacid: A novel method for the preconcentration of nortriptyline.

    PubMed

    Es'haghi, Zarrin; Hooshmand, Sara

    2015-05-01

    In this study, a new, simple, rapid, and efficient method combined with ultraviolet visible spectrophotometry and high-performance liquid chromatography analysis was developed for the extraction and determination of nortriptyline. The tendency of the Preyssler tungsten heteropolyacid, H14 [NaP5 W30 O110 ], immobilized on the surface of mesoporous nanomagnetite to adsorb the drug from the solution has been investigated. This method involves the use of an appropriate mixture of nanosorbent that was homogenized in disperser solvent (1.0 mL, ethanol). At first, the mixture containing the nanomagnetic sorbent and disperser solvent was injected into the aqueous sample, and a cloudy solution was formed. Subsequently, separation of the two phases was carried out using a magnet. In the second stage, analyte was desorbed from the sorbent by methanol as the optimal desorption solvent using sonication method. The elution solvent containing enriched analyte was introduced to the instruments for further analysis. Optimization of experimental conditions with respect to the extraction efficiency was investigated. The method was linear in the range of 25-5000, while the detection limit (LOD = 3SB /m) was 7.9 ng/mL and the limit of quantification (LOQ = 10SB /m) was 26.4 ng/mL. The relative standard deviation was 4.66%. The method was successfully applied to human hair samples. PMID:25707462

  11. TESTING SOLIDS SETTING APPARATUSES FOR DESIGN AND OPERATION OF WET-WEATHER FLOW SOLIDS-LIQUID SEPARATION PROCESSES

    EPA Science Inventory

    This study was a side-by-side comparison of two settling evaluation methods: one traditional and one new. The project investigated whether these column tests were capable of capturing or representing the rapidly settling particles present in wet-weather flows (WWF). The report r...

  12. An approach to improve the separation of solid-liquid suspensions in inclined plate settlers: CFD simulation and experimental validation.

    PubMed

    Salem, A I; Okoth, G; Thöming, J

    2011-05-01

    The most important requirements for achieving effective separation conditions in inclined plate settler (IPS) are its hydraulic performance and the equal distribution of suspensions between settler channels, both of which depend on the inlet configuration. In this study, three different inlet structures were used to explore the effect of feeding a bench scale IPS via a nozzle distributor on its hydraulic performance and separation efficiency. Experimental and Computational Fluid Dynamic (CFD) analyses were carried out to evaluate the hydraulic characteristics of the IPS. Comparing the experimental results with the predicted results by CFD simulation implies that the CFD software can play a useful role in studying the hydraulic performance of the IPS by employing residence time distribution (RTD) curves. The results also show that the use of a nozzle distributor can significantly enhance the hydraulic performance of the IPS, which contributes to the improvement of its separation efficiency. PMID:21546049

  13. Three-dimensional hotspots in evaporating nanoparticle sols for ultrahigh Raman scattering: solid-liquid interface effects

    NASA Astrophysics Data System (ADS)

    Sun, Yudie; Han, Zhenzhen; Liu, Honglin; He, Shengnan; Yang, Liangbao; Liu, Jinhuai

    2015-04-01

    Three-dimensional (3D) hotspots for ultrahigh surface-enhanced Raman scattering (SERS) has been experimentally demonstrated by evaporating a droplet of citrate-Ag sols on both hydrophobic and hydrophilic flat surfaces. Interestingly, the hydrophobic surface increased the Raman enhancement by two orders of magnitude and exhibits a better signal stability than the hydrophilic one. This study highlights the differences between hydrophilic and hydrophobic surfaces in enhanced Raman scattering by the use of extremely diluted rhodamine 6G (R6G) as the SERS reporter. In situ synchrotron-radiation small-angle X-ray scattering (SR-SAXS) was employed to explore the evolution of the 3D geometry of Ag nanoparticles in a single droplet and verify the influence mechanism of these two kinds of surface. The ideal situation of 3D self-assembly of nanoparticles in the evaporation process is a collaborative behaviour, but our results evidenced that a progressive 3D self-assembly of nanoparticles was more preferred due to the interface effects. Our experimental data derived from in situ SR-SAXS reveals that a truly distinct 3D geometry of the Ag particles develops during the evaporation process on both hydrophilic and hydrophobic surfaces. In this type of 3D geometry, the increased uniformity of the interparticle distance induced a sharp peak of the SR-SAXS signal, differing significantly from the dry state. In particular, the fluorosilylated surface reduces the interaction with particles and decreases the electrostatic adsorption on the flat surface, which helps to control the interparticle distance to remain within a small range, produce a larger number of hotspots in 3D space, and amplify the SERS enhancement accordingly.Three-dimensional (3D) hotspots for ultrahigh surface-enhanced Raman scattering (SERS) has been experimentally demonstrated by evaporating a droplet of citrate-Ag sols on both hydrophobic and hydrophilic flat surfaces. Interestingly, the hydrophobic surface increased the Raman enhancement by two orders of magnitude and exhibits a better signal stability than the hydrophilic one. This study highlights the differences between hydrophilic and hydrophobic surfaces in enhanced Raman scattering by the use of extremely diluted rhodamine 6G (R6G) as the SERS reporter. In situ synchrotron-radiation small-angle X-ray scattering (SR-SAXS) was employed to explore the evolution of the 3D geometry of Ag nanoparticles in a single droplet and verify the influence mechanism of these two kinds of surface. The ideal situation of 3D self-assembly of nanoparticles in the evaporation process is a collaborative behaviour, but our results evidenced that a progressive 3D self-assembly of nanoparticles was more preferred due to the interface effects. Our experimental data derived from in situ SR-SAXS reveals that a truly distinct 3D geometry of the Ag particles develops during the evaporation process on both hydrophilic and hydrophobic surfaces. In this type of 3D geometry, the increased uniformity of the interparticle distance induced a sharp peak of the SR-SAXS signal, differing significantly from the dry state. In particular, the fluorosilylated surface reduces the interaction with particles and decreases the electrostatic adsorption on the flat surface, which helps to control the interparticle distance to remain within a small range, produce a larger number of hotspots in 3D space, and amplify the SERS enhancement accordingly. Electronic supplementary information (ESI) available: Calculation of the focal volume, effects of focal depth. See DOI: 10.1039/c5nr00359h

  14. Physical Characterization of Solid-Liquid Slurries at High Weight Fractions Using Optical and Ultrasonic Methods, Final Report

    SciTech Connect

    Burgess, Lloyd W.

    2009-09-17

    Remediation of highly radioactive waste is a major technical and programmatic challenge for the DOE. Rapid, on-line physical characterization of highly concentrated slurries is required for the safe and efficient remediation of 90 million gallons of high level radioactive waste (HLW), sodium bearing waste, and mixed waste. The research presented here, describes a collaborative effort between Pacific Northwest National Laboratory (PNNL) and the University of Washington to directly address the need for rapid on-line characterization of the physical properties of HLW slurries during all phases of the remediation process, from in-tank characterization of sediments to monitoring of the concentration, particle size, and degree of agglomeration and gelation of slurries during transport. Near-surface characterization of the slurry flow in the particle size range from nanometer to micrometer is examined using optical low coherence reflectometry. Volumetric characterization at depths in the slurry flow, up to several centimeters in the particle size range from the micrometer to millimeter, is realized by utilizing ultrasonic backscatter and diffuses fields. One of the strengths, the teaming up of significant talents in both experimental and theoretical optics (University of Washington) and in ultrasonics [Pacific Northwest National Laboratory (PNNL)] provides a synergistic approach to integrate these complimentary techniques. One of the benefits of this combined approach is the physical characterization of HLW over a concentration and particle size range that is broader than can be achieved with today’s technology. This will avoid a costly increase in waste stream volume due to excess dilution, and will lessen chance of plugging pipes that could shut down expensive processing lines.

  15. Operation of a 24 MTD solid-liquid calciner (SLC) for liquor purification in a Bayer plant

    SciTech Connect

    Fenger, J. [F.L. Smidth and Co. A Ilkjaer, J. [FLS Minerals A Fleming, L.; Pulpeiro, J.; Carruthers, A.

    1996-10-01

    FLS Minerals, in association with Aughinish Alumina, Alumina Espanola, and Alcan International, has developed a liquor purification system for alumina refineries. Laboratory work has been carried out to characterize the behavior of different feed slurries, and several tests have been carried out on a 24 MTD pilot plant at the FLS Research Centre in Denmark. This paper reports the results of the laboratory work and the operation of the pilot unit. Examples of start-up and shut-down sequences are described.

  16. Development of a concentration measurement technique for steady state solid-liquid mixing using a neural network

    NASA Astrophysics Data System (ADS)

    Doh, Deog Hee; Yum, Joo Ho; Cho, Gyeong Rae; Kim, Myung Ho; Ryu, Gyong Won; Takei, Masahiro

    2013-10-01

    A measurement technique that can measure the concentration of the solid particles in liquid flow was developed. The measurement system consists of a color camera and three LCD displays. The solid particles were put at the bottom of a cylindrical mixing tank in which JetA1 oil was filled. Transient mixing of the solid particles was performed by rotating a propeller type agitator with three different rotation speed (500, 600, 700 r/min). Mixing state was visualized by the LCD displays and a color camcorder. The color intensity of the glass particles changes with their concentration. The color information was decoded into three principle colors R, G, and B so that, the calibration curve of color-to-concentration was performed using these information. A neural network was used for this calibration. The transient concentration field of the solid particles was quantitatively visualized.

  17. Modeling the Voltage Dependence of Electrochemical Reactions at Solid-Solid and Solid-Liquid Interfaces in Batteries

    NASA Astrophysics Data System (ADS)

    Leung, Kevin

    2015-03-01

    Electrochemical reactions at electrode/electrolyte interfaces are critically dependent on the total electrochemical potential or voltage. In this presentation, we briefly review ab initio molecular dynamics (AIMD)-based estimate of voltages on graphite basal and edge planes, and then apply similar concepts to solid-solid interfaces relevant to lithium ion and Li-air batteries. Thin solid films on electrode surfaces, whether naturally occuring during power cycling (e.g., undesirable lithium carbonate on Li-air cathodes) or are artificially introduced, can undergo electrochemical reactions as the applied voltage varies. Here the onset of oxidation of lithium carbonate and other oxide thin films on model gold electrode surfaces is correlated with the electronic structure in the presence/absence of solvent molecules. Our predictions help determine whether oxidation first occurs at the electrode-thin film or electrolyte-thin film interface. Finally, we will critically compare the voltage estimate methodology used in the fuel cell community with the lithium cohesive energy calibration method broadly applied in the battery community, and discuss why they may yield different predictions. This work was supported by Nanostructures for Electrical Energy Storage (NEES), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DESC0001160. Sandia National Laboratories is a multiprogram laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Deparment of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  18. BEHAVIOR OF SURFACTANT MIXTURES AT SOLID/LIQUID AND OIL/LIQUID INTERFACES IN CHEMICAL FLOODING SYSTEMS

    SciTech Connect

    Prof. P. Somasundaran

    2003-03-31

    The aim of the project is to develop a knowledge base to help with the design of enhanced process for mobilizing and extracting untrapped oil. We emphasize on evaluating novel surfactant mixtures and on obtaining optimum combinations of the surfactants in chemical flooding EOR process. An understanding of the micellar shape and size is crucial since these physical properties directly determine the crude oil removal efficiency. Analytical ultracentrifugation experiments were used to test the multi-micelle model proposed earlier and formulate the relationships between mixed micelle formation and the surfactant structure. Information on partial specific volume of surfactants and their mixtures is required to treat analytical ultracentrifuge data. In the last report, it was noted that the partial specific volumes of the sugar-based surfactants obtained experimentally did not agree with those from theoretical calculations. A scrutiny of partial specific volumes of the four sugar-based surfactants revealed that conformational changes upon micelle formation are responsible for the large deviation. From sedimentation equilibrium experiments, two types of micelles were identified for the nonionic polyethylene surfactant and its mixtures with the sugar-based surfactant, dodecyl maltoside. The average aggregation numbers of n-dodecyl-{beta}-D-maltoside and nonyl phenol ethoxylated decyl ether agreed with those reported in literature using other techniques. Our study displayed, for the first time, that small micelles might coexist with large micelles at high concentrations due to unique structures of the surfactant although classical thermodynamic theory supports only one type of micelle. Initial dynamic light scattering results support the results for the same mixed surfactant system from analytical ultracentrifuge equilibrium technique. The implication of this finding lies in the fact that efficiency of oil recovery will be improved due to the large micellar size, its polymer-like fluidity and possible reduced adsorption on solids.

  19. Trap characterization in composite of solid-liquid using dual-level trap model and TSDC method

    NASA Astrophysics Data System (ADS)

    Wei, Yanhui; Chen, George; Zhang, Guan-Jun; Liu, Ning; Li, Guochang

    2016-07-01

    Charge trap is considered to be one of the effective characteristic parameters for qualitatively evaluating the aging status of insulating material. In this paper, the trap characteristics in oil-impregnated paper with different aging types (non-treatment, thermal treatment and electrical treatment) are investigated using a dual-level (shallow and deep energy) trap model based on space charge profiles and thermally stimulated depolarization current (TSDC) data. The simulated results based on the model are well consistent with the experimental results. On the other hand, the TSDC method can acquire much information related to the shallower traps, and the dual-level trap model can obtain much charge dynamics characteristics. It has been observed that thermally aging makes the shallow trap energy become deeper while electrically aging makes it shallower. Moreover, the trap density in oil-impregnated paper increases after aging regardless of thermal or electrical aging.

  20. BEHAVIOR OF SURFACTANT MIXTURES AT SOLID/LIQUID AND OIL/LIQUID INTERFACES IN CHEMICAL FLOODING SYSTEMS

    SciTech Connect

    P. Somasundaran

    2004-11-20

    The aim of the project is to develop a knowledge base to help the design of enhanced processes for mobilizing and extracting untrapped oil. We emphasize evaluation of novel surfactant mixtures and obtaining optimum combinations of the surfactants for efficient chemical flooding EOR processes. In this regard, an understanding of the aggregate shape, size and structure is crucial since these properties govern the crude oil removal efficiency. During the three-year period, the adsorption and aggregation behavior of sugar-based surfactants and their mixtures with other types of surfactants have been studied. Sugar-based surfactants are made from renewable resources, nontoxic and biodegradable. They are miscible with water and oil. These environmentally benign surfactants feature high surface activity, good salinity, calcium and temperature tolerance, and unique adsorption behavior. They possess the characteristics required for oil flooding surfactants and have the potential for replacing currently used surfactants in oil recovery. A novel analytical ultracentrifugation technique has been successfully employed for the first time, to characterize the aggregate species present in mixed micellar solution due to its powerful ability to separate particles based on their size and shape and monitor them simultaneously. Analytical ultracentrifugation offers an unprecedented opportunity to obtain important information on mixed micelles, structure-performance relationship for different surfactant aggregates in solution and their role in interfacial processes. Initial sedimentation velocity investigations were conducted using nonyl phenol ethoxylated decyl ether (NP-10) to choose the best analytical protocol, calculate the partial specific volume and obtain information on sedimentation coefficient, aggregation mass of micelles. Four softwares: OptimaTM XL-A/XL-I data analysis software, DCDT+, Svedberg and SEDFIT, were compared for the analysis of sedimentation velocity experimental data. The results have been compared to that from Light Scattering. Based on the tests, Svedberg and SEDFIT analysis were chosen for further studies.