Note: This page contains sample records for the topic solide-liquide application aux from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: August 15, 2014.
1

I Situ Spectro-Ellipsometry on Solid\\/liquid Interfaces and Applications to Electrochemistry  

Microsoft Academic Search

A fast scanning spectroscopic ellipsometer with an optical multichannel analyzer detection system has been developed and applied to study static as well as kinetic phenomena at the solid-liquid interface, such as electrochemical processes, molecular adsorption and the growth of polymers on metal surface. Electrochemical behavior of polycrystalline gold was monitored as the anodic potential was increased up to 1.5 V

Yeon-Taik Kim

1990-01-01

2

Engineering evaluation of solids/liquids separation processes applicable to sludge treatment project  

SciTech Connect

This engineering study looks at the solids/liquids separation unit operations after the acid dissolution of the K Basin sludge treatment. Unit operations considered were centrifugation, filtration (cartridge, cross flow, and high shear filtration) and gravity settling. The recommended unit operations for the solids/liquids separations are based upon the efficiency, complexity, and off-the-shelf availability and adaptability. The unit operations recommended were a Robatel DPC 900 centrifuge followed by a nuclearized 31WM cartridge filter. The Robatel DPC 900 has been successfully employed in the nuclear industry on a world wide scale. The 31WM cartridge filter has been employed for filtration campaigns in both the government and civilian nuclear arenas.

Duncan, J.B.

1998-08-25

3

Three-body interactions and solid-liquid phase equilibria: Application of a molecular dynamics algorithm  

Microsoft Academic Search

The effect of three-body interactions on the solid-liquid phase boundaries of argon, krypton, and xenon is investigated via a novel technique that combines both nonequilibrium and equilibrium molecular dynamics. The simulations involve the evaluation of two- and three-body forces using accurate two-body and three-body intermolecular potentials. The effect of three-body interactions is to substantially increase the coexistence pressure and to

Liping Wang; Richard J. Sadus

2006-01-01

4

Predictive local composition models: NRTL and UNIQUAC and their application to model solid–liquid equilibrium of n-alkanes  

Microsoft Academic Search

Excess Gibbs energy models based on the local composition concept are applied to the description of the solid–liquid equilibria of paraffins. The energetic parameters used by these models are estimated `a priori' by relating the interaction energies between pairs of molecules with their enthalpies of sublimation providing a pure predictive model for the description of solid–liquid equilibria of systems with

João Araújo Pereira Coutinho; Pereira Coutinho

1999-01-01

5

I Situ Spectro-Ellipsometry on Solid/liquid Interfaces and Applications to Electrochemistry.  

NASA Astrophysics Data System (ADS)

A fast scanning spectroscopic ellipsometer with an optical multichannel analyzer detection system has been developed and applied to study static as well as kinetic phenomena at the solid-liquid interface, such as electrochemical processes, molecular adsorption and the growth of polymers on metal surface. Electrochemical behavior of polycrystalline gold was monitored as the anodic potential was increased up to 1.5 V vs saturated calomel electrode (SCE). In the range of 1 to 1.5 V in highly acidic media (0.5 M H _2SO_4), gold oxides form in two different oxidation states, namely, AuOH at 1.1 V and a higher oxidation state of gold oxide at 1.3 V. The fast scanning spectroscopic ellipsometry enabled us to determine the optical properties (dielectric functions) and the thickness of the gold hydroxide and oxide species. As a result, the monolayer thickness of AuOH was determined to be 3.0 +/- 0.5 A, and that of gold oxide was 4.0 +/- 0.3 A. As far as the optical properties are concerned, the higher oxidation state of gold oxide shows more absorbance than that of AuOH corresponding to the higher order of the charge transfer for gold oxide. Deposition of a conducting polymer (polypyrrole) at an anodic potential was monitored as a function of time, every 7.5 seconds in aqeuous 0.1 M KNO_3 . The optical properties of oxidized polypyrrole in 0.1 M KNO_3 electrolyte was determined in situ using spectroscopic ellipsometry with optical multichannel analyzer detection. The determined dielectric function revealed the interband transitions at 3.8 eV and a transition at 1.7 eV suggesting high doping concentrations under our preparation condition of the oxidized polypyrrole. Also, the dielectric function of the oxidized polypyrrole and LRA allowed us to characterize the nucleation and growth of the polypyrrole. As a result, (i) monomer adsorption, (ii) two-dimensional nucleation and (iii) three-dimensional growth could be determined during the electrochemical deposition of polypyrrole. Finally, the orientational phase transition of the pyridine molecules on silver surface was studied by the measurement of surface plasmon polariton using spectorscopic ellipsometry. We could observe this phase transition at approximately 1 times 10 ^{-4} M of pyridine concentration in water at room temperature. Below 1 times 10^{-4} M, the ring of the pyridine is parallel to the silver surface; above 1 times 10^ {-4} M, the ring is aligned perpendicular to the surface.

Kim, Yeon-Taik

1990-01-01

6

Application de la combustion catalytique aux turbines à gaz  

NASA Astrophysics Data System (ADS)

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.

Lebas, E.; Martin, G. H.

2002-04-01

7

The interaction of elastic waves with a solid-liquid interface, with applications to the core-mantle boundary  

Microsoft Academic Search

The paper discusses basic ideas and principles underlying methods, which have proved useful in the interpretation of diffraction and scattering phenomena by a smooth or slightly rough solid-liquid interface. Generally, the wave interaction may be formulated as an excitation problem; it involves (1) finding an equivalent dislocation or source distribution on the interface, and (2) evaluating the excited wave field.

D. J. Doornbos; J. C. Mondt

1980-01-01

8

Solids, Liquids, and Gases  

NSDL National Science Digital Library

In this project you will research solids, liquids, and gases. By the end of this project you will be able to answer the question: Can you tell what is alike and different between solids, liquids, and gases? Read the song about matter. song with music about matter Record your observations on the organizer provided by the teacher. On the diagram write the word solid in one of the circles. Write liquid in one of the circles and write gas in the last circle. As you collect your information write your information under ...

Sibley, Ms.

2009-10-22

9

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

NASA Astrophysics Data System (ADS)

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 ?-Al5Fe2, ?-Al13Fe4, and ?-Al8Fe2Si phases grow at different times and rates during the dipping process, whereas the face-centered cubic AlFe3 phase is not formed.

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

2014-04-01

10

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  

Microsoft Academic Search

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

R. B. Symonds; M. H. Reed

1993-01-01

11

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

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

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

1993-01-01

12

Application of a novel type impinging streams reactor in solid-liquid enzyme reactions and modeling of residence time distribution using GDB model.  

PubMed

Solid-liquid enzyme reactions constitute important processes in biochemical industries. The isomerization of d-glucose to d-fructose, using the immobilized glucose isomerase (Sweetzyme T), as a typical example of solid-liquid catalyzed reactions has been carried out in one stage and multi-stage novel type of impinging streams reactors. Response surface methodology was applied to determine the effects of certain pertinent parameters of the process namely axial velocity (A), feed concentration (B), nozzles' flow rates (C) and enzyme loading (D) on the performance of the apparatus. The results obtained from the conversion of glucose in this reactor were much higher than those expected in conventional reactors, while residence time was decreased dramatically. Residence time distribution (RTD) in a one-stage impinging streams reactor was investigated using colored solution as the tracer. The results showed that the flow pattern in the reactor was close to that in a continuous stirred tank reactor (CSTR). Based on the analysis of flow region in the reactor, gamma distribution model with bypass (GDB) was applied to study the RTD of the reactor. The results indicated that RTD in the impinging streams reactor could be described by the latter model. PMID:24411440

Fatourehchi, Niloufar; Sohrabi, Morteza; Dabir, Bahram; Royaee, Sayed Javid; Haji Malayeri, Adel

2014-02-01

13

Application of the New Decommissioning Regulation to the Nuclear Licensed Facilities (NLF) at Fontenay-aux-Roses's Nuclear Center (CEA)  

Microsoft Academic Search

This abstract describes the application of the new decommissioning regulation on all Nuclear Licensed Facilities (NLF is to say INB in French) at Fontenay-aux-Roses's Center (CEA\\/FAR). The decommissioning process has been applied in six buildings which are out of the new nuclear perimeter proposed (buildings no 7, no 40, no 94, no 39, no 52\\/1 and no 32) and three

Josiane Sauret; Laurence Piketty; Michel Jeanjacques

2008-01-01

14

Solid–liquid expression of cellular materials enhanced by pulsed electric field  

Microsoft Academic Search

The mechanism of solid–liquid expression enhanced by pulsed electric field (PEF) is studied for agrofood cellular materials. The application of PEF induces the permeabilization of cellular membranes and facilitates the subsequent cells rupture by mechanical compression. The solid–liquid expression was preceded by mechanical pre-compaction of sugar beet slices under a constant pressure, application of PEF treatment under the same pressure,

Hazem Bouzrara; Eugene Vorobiev

2003-01-01

15

Perturbation theory of solid-liquid interfacial free energies of bcc metals  

SciTech Connect

A perturbation theory is used to calculate bcc solid-liquid interfacial free energies of metallic systems with embedded-atom model potentials. As a reference system for bcc crystals we used a single-occupancy cell, hard-sphere bcc system. Good agreements between the perturbation theory results and the corresponding results from simulations are found. The strategy to extract hard-sphere bcc solid-liquid interfacial free energies may have broader applications for other crystal lattices.

Warshavsky, Vadim B.; Song, Xueyu

2012-09-18

16

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

Microsoft Academic Search

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

Luning Zhang

2008-01-01

17

Ordering at solid-liquid interfaces  

Microsoft Academic Search

The surface of a crystal is the place where the crystal interacts with its environment. Knowledge of the atomic structure of a solid-liquid interface is important to understand the different processes occurring at the surface, such as crystal growth. Both the structure at the solid side and on the liquid side of the interface deviate from the bulk structure. The

Marianne Frederika Reedijk

2003-01-01

18

Solid-liquid equilibrium for quadrupolar molecules  

Microsoft Academic Search

Theoretical calculations are presented of solid-liquid equilibrium for linear quadrupolar molecules, focusing especially on the ratio of the triple point temperature to the critical temperature. The proposed treatment uses the hard quadrupolar dumbbell model as the reference system, and incorporates the effect of dispersion forces through a mean-field term. The reference system of quadrupolar hard dumbbells is described using perturbation

C. Vega; P. A. Monson

1995-01-01

19

Solid liquid surface energy of pivalic acid  

NASA Astrophysics Data System (ADS)

The Gibbs-Thomson coefficient and the solid-liquid surface energy for pivalic acid have been measured by a direct method. The grain boundary energy of the pivalic acid also has been calculated from the observed grain boundary groove shapes.

Bayender, B.; Mara?li, N.; Çadirli, E.; ?i?man, H.; Gündüz, M.

1998-11-01

20

Diffusion de neutrons aux petits angles : application à l'étude des macromolécules biologiques en solution  

NASA Astrophysics Data System (ADS)

La diffusion de neutrons aux petits angles (DNPA) permet de sonder les propriétés statiques de la matière sur une échelle spatiale allant de quelques dixièmes à quelques dizaines de nanomètres. Cette technique est ainsi particulièrement bien adaptée à l'étude des macromolécules en solution. Il est possible d'accéder à des grandeurs moyennes qui caractérisent la conformation qu'adoptent les macromolécules ou leurs interactions thermodynamiques. Le cours expose à des non spécialistes les différentes grandeurs mesurables et les méthodes à utiliser pour y accéder. En particulier sont abordées: 1) les mesures effectuées dans la limite du vecteur de diffusion nul qui sont liées aux fluctuations de concentration; 2) les notions de facteur de forme, de facteur de structure dots 3) les différentes façon de jouer avec le contraste. Les notions introduites sont illustrées par des exemples didactiques empruntés à la littérature et concernant des macromolécules biologiques en solution.

Lairez, D.; Pelta, J.

2005-11-01

21

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)

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.

Zeng, X. C.; Stroud, D.

1989-01-01

22

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

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.

Symonds, R.B. (Michigan Technology Univ., Houghton, MI (United States)); Reed, M.H. (Univ. of Oregon, Eugene, OR (United States))

1993-10-01

23

Application of the New Decommissioning Regulation to the Nuclear Licensed Facilities (NLF) at Fontenay-aux-Roses's Nuclear Center (CEA)  

SciTech Connect

This abstract describes the application of the new decommissioning regulation on all Nuclear Licensed Facilities (NLF is to say INB in French) at Fontenay-aux-Roses's Center (CEA/FAR). The decommissioning process has been applied in six buildings which are out of the new nuclear perimeter proposed (buildings no 7, no 40, no 94, no 39, no 52/1 and no 32) and three buildings have been reorganized (no 54, no 91 and no 53 instead of no 40 and no 94) in order to increase the space for temporary nuclear waste disposal and to reduce the internal transports of nuclear waste on the site. The advantages are the safety and radioprotection improvements and a lower operating cost. A global safety file was written in 2002 and 2003 and was sent to the French Nuclear Authority on November 2003. The list of documents required is given in the paragraph I of this paper. The main goals were two ministerial decrees (one decree for each NLF) getting the authorization to modify the NLF perimeter and to carry out cleaning and dismantling activities leading to the whole decommissioning of all NLF. Some specific authorizations were necessary to carry out the dismantling program during the decommissioning procedure. They were delivered by the French Nuclear Safety Authority (FNSA) or with limited delegation by the General Executive Director (GED) on the CEA Fontenay-aux-Roses's Center, called internal authorization. Some partial dismantling or decontamination examples are given below: - evaporator for the radioactive liquid waste treatment station (building no 53): FNSA authorization: phase realised in 2002/2003. - disposal tanks for the radioactive liquid waste treatment station (building no 53) FNSA authorization: phase realised in 2004, - incinerator for the radioactive solid waste treatment station (building no 07): FNSA authorization: operation realised in 2004, - research equipments in the building no. 54 and building no. 91: internal authorization ; realised in 2005, - sample-taking to characterize solvent contained in one tank of Petrus installation (NLF 57, building 18) for radiological and chemical analysis needed to prepare the treatment and the evacuation of these wastes : internal authorization ; realised in june 2005. It was possible to plan the whole decommissioning process on the Nuclear Licensed Facilities of Fontenay-aux-Roses's Center (CEA/FAR) taking into account the French new regulation and to plan a coherent and continue program activity for the dismantling process. For the program not to be interrupted during the administrative process (2003-2006), specific authorisations have been delivered by the French Nuclear Safety Authority or by the General Executive Director (GED) on the CEA Fontenay-aux- Roses's Center (internal authorization). The time schedule to complete the entire program is until 2017 for NLF 'Procede' (NLF no 165) and until 2018 for NLF 'Support' (NLF no 166). Since 1999, an annual press meeting has been organised by the Fontenay-aux-Roses's Center Head Executive Manager.

Sauret, Josiane [Commissariat a l'Energie Atomique, Direction du Centre de Fontenay-aux-Roses, Cellule de Surete nucleaire, de controle des Matieres, de controle des Transports et de la Qualite, 18 route du Panorama BP 6 - 92265 Fontenay-aux-Roses Cedex (France); Piketty, Laurence; Jeanjacques, Michel [Commissariat a l'Energie Atomique, Direction de l'Energie Nucleaire, Direction deleguee des Activites Nucleaires de Saclay, Departement des Reacteurs et des Services Nucleaires, service d'Assainissement de Fontenay-aux-Roses, 18 route du Panorama BP 6 - 92265 Fontenay-aux-Roses Cedex (France)

2008-01-15

24

Solid-liquid phase transition in argon  

NASA Technical Reports Server (NTRS)

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.

Tsang, T.; Tang, H. T.

1978-01-01

25

Élaboration de couches minces de carbone par ablation laser femtoseconde pour application aux biomatériaux implantables  

NASA Astrophysics Data System (ADS)

Des films de tetrahedral amorphous-Carbon (ta-C) ont été déposés, sous vide poussé, par ablation d'une cible de graphite avec un laser Ti : saphir (durée d'impulsion 170 fs, fréquence de répétition 1 kHz, énergie maximale par impulsion 1,5 mJ, longueur d'onde 800 nm) sur substrats standard et sur biomatériaux (acier AISI 316L, polyéthylène à très haut poids moléculaire). Les propriétés de ces couches (structure, propriétés nanomécaniques et tribologiques) ont été caractérisées, en fonction des conditions d'élaboration, en examinant l'intérêt de l'utilisation d'un laser femtoseconde et leur capacité à satisfaire aux exigences spécifiques du domaine biomédical. Les propriétés d'adhérence des films ont été considérablement améliorées lors du dépôt sur des substrats en acier inoxydable préalablement préparés par décapage ionique in situ sous atmosphère d'argon. La surface hémisphérique d'une tête fémorale, en acier inoxydable, de prothèse de hanche de diamètre 22,2 mm a été revêtue d'un film de DLC adhérent et homogène en épaisseur. La résistance à l'usure de ce revêtement sera quantifiée à l'aide d'un simulateur de marche durant un million de cycles (correspondant à une année d'activité physique d'un être humain).

Loir, A.-S.; Garrelie, F.; Donnet, C.; Subtil, J.-L.; Belin, M.; Forest, B.; Rogemond, F.; Laporte, P.

2005-06-01

26

Experimental Study of Solid - Liquid Mass Transfer in Column with Structured Packing  

Microsoft Academic Search

The structured packing beds are increasingly focusing the attention of industrialists and researchers in chemical engineering. Several of its applications, mainly in the field of chemical processes, imply solid-liquid mass transfer steps in beds of solid particles sandwiched in the structure of packing. The kinetics of mass transfer in this type of heterogeneous systems is scarcely reported in the open

G. Soare; R. Dima; V. Plesu

27

Solid-liquid interfacial energy of pyrene  

NASA Astrophysics Data System (ADS)

The equilibrated grain boundary groove shapes for commercial purity pyrene (PY) were directly observed by using a temperature gradient stage. From the observed grain boundary groove shapes, the Gibbs-Thomson coefficient and solid-liquid interfacial energy of PY have been determined to be (8.9+/-0.9)×10-8 K m and (21.9+/-3.3)×10-3 J m-2 with the present numerical model and Gibbs-Thomson equation, respectively. The grain boundary energy of PY phase has been determined to be (42.8+/-7.3)×10-3 J m-2 from the observed grain boundary groove shapes. Thermal conductivity ratio of liquid phase to solid phase has also been measured to be 0.89.

Akbulut, S.; Ocak, Y.; Böyük, U.; Erol, M.; Ke?lio?lu, K.; Mara?l?, N.

2006-12-01

28

Computational Investigations of Solid-Liquid Interfaces  

SciTech Connect

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.

Mark Asta

2011-08-31

29

A Theory of Cavity Formation at Solid-Liquid Interfaces.  

National Technical Information Service (NTIS)

A theory of cavity formation at solid-liquid interfaces was derived which describes cavitational behavior in terms of the dispersion forces and of the surface tension of the liquid. The resulting relationships are easily applied to experimental data with ...

D. J. Cotton

1969-01-01

30

Nanostructuring of liquids at solid-liquid interfaces  

Microsoft Academic Search

The behavior of liquid molecules, confined in nanometer-scale spaces or at solid-liquid interfaces, is quite different from that in the bulk, which is attributed to the surface-induced structuring of liquids. The structuring of liquids at solid-liquid interfaces was investigated by employing new approaches based on surface force measurement. The combination of surface force measurement and Fourier transform IR spectroscopy in

Kazue Kurihara

31

Nanostructuring of liquids at solid—liquid interfaces  

Microsoft Academic Search

The behavior of liquid molecules, confined in nanometerscale spaces or at solid—liquid interfaces, is quite different from\\u000a that in the bulk, which is attributed to the surface-induced structuring of liquids. The structuring of liquids at solid—liquid\\u000a interfaces was investigated by employing new approaches based on surface force measurement. The combination of surface force\\u000a measurement and Fourier transform IR spectroscopy in

Kazue Kurihara

32

The influence of solid–liquid interactions on dynamic wetting  

Microsoft Academic Search

The molecular-kinetic theory of dynamic wetting has been extended to take specific account of solid–liquid interactions. By equating the work of adhesion with the surface component of the specific activation free energy of wetting, equations have been derived which show the way in which solid–liquid interactions modify both the driving force and the resistance to wetting. For a liquid meniscus

T. D Blake; J De Coninck

2002-01-01

33

Solid + liquid phase equilibria in the hydroxylammonium nitrate + water system  

Microsoft Academic Search

The binary solid + liquid phase diagram has been measured for the water + hydroxylammonium nitrate (HAN) system. The phase diagram is a simple eutectic type with the eutectic at 231.5 K (41.7°C) and a mole fraction HAN of 0.281 (wt fraction HAN - 0.676).The enthalpy of fusion of the HAN was determined from the solid + liquid results to

Johanne I. Artman; J. Bevan Ott

1989-01-01

34

Electric current effects on solid-solid and solid-liquid metallic reactions  

Microsoft Academic Search

The interactions at high temperatures between contacting dissimilar metals and the nature of the phases formed from such interactions are of importance in a variety of applications. Solid-solid interactions are important in such considerations as fiber-matrix reactions, diffusion bonding, and electromigration in interconnects in electronic devices, while solid-liquid interactions have practical significance in liquid metal infiltration, soldering and brazing, liquid-metal

Jinfeng Zhao

2008-01-01

35

Detecting solid liquid interface properties with mechanical slip modelling for quartz crystal microbalance operating in liquid  

Microsoft Academic Search

Quartz crystal microbalances (QCMs) provide sensitive probes for changes at solid-solid or solid-liquid interfaces. It is essential to obtain a physical insight into the details of the interface loading mechanism to interpret the observed behaviour leading to fresh applications of AT-cut quartz resonators. In this work, a mechanical slip model of the interface between a quartz plate and a viscoelastic

F. Lu; H. P. Lee; S. P. Lim

2004-01-01

36

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

NASA Astrophysics Data System (ADS)

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{?}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.

Lhuillier, Emmanuel

2010-11-01

37

X-rays at Solid-Liquid Surfaces  

SciTech Connect

Solid-liquid interfaces play an important role in many areas of current and future technologies, and in our biosphere. They play a key role in the development of nanofluidics and nanotribology, which sensitively depend on our knowledge of the microscopic structures and phenomena at the solid-liquid interface. The detailed understanding of how a fluid meets a wall is also a theoretical challenge. In particular, the phenomena at repulsive walls are of interest, since they affect many different phenomena, such as water-repellent surfaces or the role of the hydrophobic interaction in protein folding. Recent x-ray reflectivity studies of various solid-liquid interfaces have disclosed rather intriguiing phenomena, which will be discussed in this lecture: premelting of ice in contact with silica; liquid Pb in contact with Si; water in contact with hydrophobic surfaces. These experiments, carried out with high-energy x-ray microbeams, reveal detailed insight into the liquid density profile closest to the wall. A detailed insight into atomistic phenomena at solid-liquid interfaces is also a prerequisite in the microscopic control of electrochemical reactions at interfaces. Recent x-ray studies show the enormous future potential of such non-destructive analytical tools for the in situ observation of (electro-)chemical surface reactions. This lecture will review recent x-ray experiments on solid-liquid interfaces.

Dosch, Helmut (Max Planck Institute for Metals Research) [Max Planck Institute for Metals Research

2007-05-02

38

Convection-induced distortion of a solid-liquid interface  

NASA Astrophysics Data System (ADS)

Measurements of convective flow fields and solid-liquid interface shapes during the solidification of a pure and a slightly alloyed transparent material reveal that the convective transport of solute can cause a macroscopic depression to develop in the solid-liquid interface. This effect occurs under conditions close to those which are predicted to produce morphological instability of a planar interface. A cellular or dendritic microstructure later develops within the interface depression. The convection is attributed to the effect of radial temperature gradients in the crystal growth apparatus.

Schaefer, R. J.; Coriell, S. R.

1984-12-01

39

Trends in solids/liquids poisoning suicide rates in Taiwan: a test of the substitution hypothesis  

PubMed Central

Background Several previous studies have illustrated that restricting access to lethal methods can reduce suicide rates. The most often cited example was Kreitman's study, showing a reduction not only in gas-specific suicide rates, but also in the overall suicide rates because of the lack of increase of other methods. However, method substitution is still a major concern in the application of the means restriction strategy to prevent suicide. The aim of the study was to investigate whether the reduction in the solids/liquids poisoning suicide rate in 1983-1993 after the launching of pesticide restriction interventions in Taiwan was accompanied with an increase in the suicide rate using other methods (method substitution). Methods Data on age-, sex- and method-specific suicide rates for 1971-1993 in Taiwan were obtained. Changes in solids/liquids poisoning suicide rates were compared with suicide rates by hanging and other methods between 1983 and 1993. Results No concomitant increase in suicide rates by hanging or other methods was noted from 1983 to 1993, during which the suicide rates by poisoning with solids/liquids (mainly pesticides) decreased markedly and steadily. The phenomenon of method substitution was also not found by sex and age groups. Conclusion In general, no method substitution was found along with the reduction in solids/liquids suicide rates in Taiwan. Our study results have also added the evidence that restricting access to methods maybe a promising strategy in preventing suicide, particularly in those countries where the "target method" has been found to contribute greatly to the suicide rates.

2011-01-01

40

SOLID\\/LIQUID EXTRACTION OF ZINC FROM EAF-DUST  

Microsoft Academic Search

The solid\\/liquid extraction of nonferrous heavy metals was investigated. This process may be of technical importance in the upgrading of dust from steel mills and from electrical arc furnaces (EAF-dust). Extraction was carried out with aqueous acetic acid. Objectives of the project were the evaluation of partition data and the investigation of extraction kinetics. The extraction efficiency of the substances

T. Hilber; R. Marr; M. Siebenhofer; W. Zapfel

2001-01-01

41

Interaction Between Particles and a Solid-Liquid Interface  

Microsoft Academic Search

The interaction between particles and an advancing solid-liquid interface has been investigated both experimentally and theoretically. For each particular type of particle, a ``critical velocity'' was observed, below which the particles are rejected by the interface, and above which they are trapped in the solid. The dependence of the critical velocity on various properties of matrix and particle was investigated.

D. R. Uhlmann; B. Chalmers; K. A. Jackson

1964-01-01

42

Mass Transfer Flux at Solid-Liquid Contacting Interface  

Microsoft Academic Search

When cellular materials are immersed in a solution of high concentration, the mass transfer is considered a multi-component transport process in which simultaneous and countercurrent flows occur in the biological tissue. The mass transfer process of each component in the solid-liquid system is affected not only by operational parameters, but also by the presence of other components. The main driving

J. Shi; M. Le Maguer

2003-01-01

43

Investigation of Solid/Liquid Interface Temperatures Via Isenthalpic Solidification.  

National Technical Information Service (NTIS)

Isenthalpic solidification of a pure supercooled liquid is shown to result in either a two-phase solid/liquid mixture in invariant equilibrium or a single-phase, totally solid material in univariant equilibrium, depending on the level of supercooling prio...

M. E. Glicksman R. J. Schaefer

1967-01-01

44

Statistical thermodynamics of the cluster solid-liquid transition  

Microsoft Academic Search

A direct connection between the solid-liquid transition in atomic clusters and the macroscopic phase transition is established through analysis of the size scaling of the latent heat and transition rounding. The transition occurs without phase separation, leading to remarkable consequences in caloric experiments. These features are all quantified through the characteristic shape of the classical state density, computed by a

Pierre Labastie; Robert L. Whetten

1990-01-01

45

Solid–liquid surface energy of pivalic acid  

Microsoft Academic Search

The Gibbs–Thomson coefficient and the solid–liquid surface energy for pivalic acid have been measured by a direct method. The grain boundary energy of the pivalic acid also has been calculated from the observed grain boundary groove shapes.

B. Bayender; N Mara?li; E Çadirli; H ?i?man; M Gündüz

1998-01-01

46

Solid–liquid extraction from plants — experimental kinetics and modelling  

Microsoft Academic Search

The kinetics and structural changes in the solid were studied for solid–liquid extraction from plants. Two extraction systems were investigated: tobacco leaves (Nicotiana tabacum L.)–water, and oak bark (Quercus frainetto Ten)–water. The mathematical model of the process, accounting for variable effective diffusivity and porosity, was stated and solved numerically. The solution was checked with experimental kinetics and porosity data to

E. Simeonov; I. Tsibranska; A. Minchev

1999-01-01

47

Solid–Liquid Phase Change Driven by Internal Heat Generation  

SciTech Connect

This article presents results of solid-liquid phase change, the Stefan Problem, where melting is driven internal heat generation, in a cylindrical geometry. The comparison between a quasi-static analytical solution for Stefan numbers less than one and numerical solutions shows good agreement. The computational results of phase change with internal heat generation show how convection cells form in the liquid region. A scale analysis of the same problem shows four distinct regions of the melting process.

John Crepeau; Ali s. Siahpush

2012-07-01

48

Final Report: Thermal Conductance of Solid-Liquid Interfaces  

Microsoft Academic Search

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. ;\\u000a;\\u000a 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

David Cahil; Paul Braun

2006-01-01

49

Infrared studies of adsorption at the solid\\/liquid interface  

Microsoft Academic Search

Infrared spectroscopy provides an extremely important method for the study of surface-adsorbate interactions at the solid-liquid\\u000a interface. The characterization of types of interaction and modes of adsorption can often be achieved in a way which is not\\u000a possible by any other experimental method. Several modes of adsorption involving a single adsorbate can sometimes be distinguished\\u000a and unambiguously characterized. Competitive adsorption

C. Rochester

50

Interaction of porosity with a planar solid\\/liquid interface  

Microsoft Academic Search

In this article, an investigation of the interaction between gas porosity and a planar solid\\/liquid (SL) interface is reported.\\u000a A two-dimensional numerical model able to accurately track sharp SL interfaces during solidification of pure metals and alloys\\u000a is proposed. The finite-difference method and a rectangular undeformed grid are used for computation. The SL interface is\\u000a described through the points of

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

2004-01-01

51

Photolithographic fabrication of solid-liquid core waveguides by thiol-ene chemistry  

NASA Astrophysics Data System (ADS)

In this work we demonstrate an efficient and cleanroom compatible method for the fabrication of solid-liquid core waveguides based on nanoporous polymers. We have used thiol-ene photo-grafting to tune and pattern the hydrophilicity of an originally hydrophobic nanoporous 1, 2-polybutadiene. The generated refractive index contrast between the patterned water-filled volume and the surrounding empty hydrophobic porous polymer allows for light confinement within the water-filled volume—the solid-liquid core. The presented fabrication process is simple and fast. It allows a high degree of flexibility on the type and grade of surface chemistry imparted to the large nanoporous area depending upon the application. The fabrication does not need demanding chemical reaction conditions. Thus, it can be readily used on a standard silicon lithography bench. The propagation loss values reported in this work are comparable with literature values for state-of-the-art liquid-core waveguide devices. The demonstrated waveguide function added to the nanoporous polymer with a very high internal surface area makes the system interesting for many applications in different areas, such as diagnostics and bio-chemical sensing.

Sagar, Kaushal; Gopalakrishnan, Nimi; Brøkner Christiansen, Mads; Kristensen, Anders; Ndoni, Sokol

2011-09-01

52

Solid-liquid phase equilibria from free-energy perturbation calculations  

NASA Astrophysics Data System (ADS)

A method for calculating free-energy differences based on a free-energy perturbation (FEP) formalism in an alloy system described by two different Hamiltonians is reported. The intended application is the calculation of solid-liquid phase equilibria in alloys with the accuracy of first-principles electronic density-functional theory (DFT). For this purpose free energies are derived with a classical interatomic potential, and FEP calculations are used to compute corrections to these reference values. For practical applications of this approach, due to the relatively high computational cost of DFT calculations, it is critical that the FEP calculations converge rapidly in terms of the number of samples used to estimate relevant ensemble averages. This issue is investigated in the current study employing two classical interatomic-potential models for Ni-Cu. These models yield differences in predicted phase-boundary temperatures of approximately 100 K, comparable to those that might be expected between a DFT Hamiltonian and a well-fit classical potential. We show that for pure elements the FEP calculations converge rapidly with the number of samples, yielding free-energy differences converged to within a fraction of a meV/atom in a few dozen energy calculations. For a concentrated equiatomic alloy similar precision requires roughly a hundred samples. The results suggest that the proposed methodology could provide a computationally tractable framework for calculating solid-liquid phase equilibria in concentrated alloys with DFT accuracy.

Angioletti-Uberti, Stefano; Asta, Mark; Finnis, Mike W.; Lee, P. D.

2008-10-01

53

Detecting solid–liquid interface properties with mechanical slip modelling for quartz crystal microbalance operating in liquid  

Microsoft Academic Search

Quartz crystal microbalances (QCMs) provide sensitive probes for changes at solid–solid or solid–liquid interfaces. It is essential to obtain a physical insight into the details of the interface loading mechanism to interpret the observed behaviour leading to fresh applications of AT-cut quartz resonators. In this work, a mechanical slip model of the interface between a quartz plate and a viscoelastic

F Lu; H P Lee; S P Lim

2004-01-01

54

Methods and systems for monitoring a solid-liquid interface  

DOEpatents

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.

Stoddard, Nathan G. (Gettysburg, PA); Clark, Roger F. (Frederick, MD); Kary, Tim (Union Bridge, MD)

2010-07-20

55

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

PubMed

The aim of this study was to determine the effectiveness of natural flocculants to reduce solids and nutrient loads in dairy cow wastewater using solid-liquid separation; chitosan was used as a model. Its use efficiency and optimum application rate were determined using flushed dairy cow manure of varied strengths - 0.4%, 0.8%, 1.6%, and 3.2% total solids (TS) content. Treatments consisted of nine rates of chitosan. The flocculated manure was dewatered using 1-mm and 0.25-mm screens. Separation by screening alone was not effective; average efficiencies were about 60% for total suspended solids (TSS), 22% for total Kjeldahl nitrogen (TKN), and 26% for total phosphorus (TP). Mixing with chitosan before screening substantially increased separation. At optimum chitosan rate (0.5g/L for the highest strength effluent), separation efficiencies were >95% for TSS, >73% for TKN, and >54% for TP. The results of this study indicate that natural flocculants such as chitosan are useful for the solid-liquid separation treatment of livestock wastewater. PMID:19071016

Garcia, M C; Szogi, A A; Vanotti, M B; Chastain, J P; Millner, P D

2009-11-01

56

Solid\\/liquid- and vapor-phase interactions between cellulose- and lignin-derived pyrolysis products  

Microsoft Academic Search

Solid\\/liquid- and vapor-phase interactions between cellulose- and lignin (Japanese cedar milled wood lignin)-derived pyrolysis products were studied under the conditions of N2\\/600°C\\/40–80s. A dual-space closed ampoule reactor was used to eliminate the solid\\/liquid-phase interactions, and careful comparison of the resulting data with those of the pyrolysis of the mixed samples gave some insights into the solid\\/liquid- and vapor-phase interactions separately.

Takashi Hosoya; Haruo Kawamoto; Shiro Saka

2009-01-01

57

Methods and systems for monitoring a solid-liquid interface  

DOEpatents

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, . . . ).

Stoddard, Nathan G. (Gettysburg, PA); Clark, Roger F. (Frederick, MD)

2011-10-04

58

Membrane separations for solid-liquid clarification within lignocellulosic biorefining processes.  

PubMed

Membrane separations can be integrated into a biorefinery to reduce water and energy consumption. Unfortunately, current membrane materials suffer from severe fouling, which limits their applicability. Here, using analytical characterizations along with fouling models, we correlate membrane properties with performance metrics to provide a framework for optimal membrane selection during solid-liquid clarification of a biomass hydrolysate. Five membranes were evaluated: polyether sulfone, mixed cellulose esters, and three surface modified membranes with weak acid, strong acid, and weak base functionalities. Lignin was the primary component responsible for flux decline, due to physical entrapment and chemical adsorption. The best membrane performance (high and sustained flux, low fouling, and high separation factor) was correlated with higher surface roughness, lower hydrophobicity, neutral or positively charged zeta potential, and a larger number of smaller surface pores. These analyses provide valuable information for designing new materials for biorefining processes to reduce fouling and increase stability. PMID:23813787

Leberknight, Jennifer; Menkhaus, Todd J

2013-01-01

59

Mechanisms of reduced solute diffusivity at nanoconfined solid-liquid interface  

NASA Astrophysics Data System (ADS)

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.

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

2013-06-01

60

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

NASA Astrophysics Data System (ADS)

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.

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

2012-09-01

61

A mean field approach for computing solid-liquid surface tension for nanoscale interfaces  

Microsoft Academic Search

The physical properties of a liquid in contact with a solid are largely determined by the solid-liquid surface tension. This is especially true for nanoscale systems with high surface area to volume ratios. While experimental techniques can only measure surface tension indirectly for nanoscale systems, computer simulations offer the possibility of a direct evaluation of solid-liquid surface tension although reliable

Chi-Cheng Chiu; R. J. K. Udayana Ranatunga; David Torres Flores; D. Vladimir Pérez; Preston B. Moore; Wataru Shinoda; Steven O. Nielsen

2010-01-01

62

Mass transfer in cellular material at solid–liquid contacting interface  

Microsoft Academic Search

The effective mass transfer (water and solute) and volume shrinkage were measured during solid–liquid contacting process for red beet material tissue under a wide range of process parameters. The mass transfer process of each component in the solid–liquid system is affected not only by operating parameters, but also by the matrix properties of cellular material. The main driving force for

John Shi; Marc Le Maguer

2003-01-01

63

Application des méthodes de codage optimal aux valeurs Delta : une stratégie pertinente pour l’exploration du processus thérapeutique  

Microsoft Academic Search

In multidimensional research with small samples, the application of optimal scaling techniques to Delta values (posttest–pretest differences) allows extracting latent dimensions that are theoretically sound and lead to a better understanding of the manifest changes. The posttest–pretest differences are measured with the help of several tools (psychometric scales, projective and expressive tests, observational frames, external validation criteria) that are complementary

L. Schiltz; L. Boyer; M. Konz; J. Schiltz

2010-01-01

64

A microfluidic setup for studies of solid-liquid interfaces using x-ray reflectivity and fluorescence microscopy  

SciTech Connect

In this paper we present a concept for a microfluidic chamber optimized for x-ray reflectivity studies at solid-liquid interfaces. Experiments of this kind are usually considerably limited by strong beam attenuation due to interactions with the aqueous environment. First experiments at synchrotron sources using supported model membranes showed that the microfluidic setup yields a very effective solution for minimizing background scattering and beam absorption, which are often accompanied by radiation damage of biological samples. Additionally, the setup is also well suited for the application of fluorescence microscopy. The application of these two different techniques on the same sample offers unique possibilities for complementary studies.

Reich, Christian; Hochrein, Marion B.; Krause, Baerbel; Nickel, Bert [Department fuer Physik der Ludwig-Maximilians-Universitaet Muenchen, Geschwister-Scholl-Platz 1, D-80539 Munich (Germany); European Synchrotron Radiation Facility, Boite Postale 220, F-38043 Grenoble Cedex (France); Department fuer Physik der Ludwig-Maximilians-Universitaet Muenchen, Geschwister-Scholl-Platz 1, D-80539 Munich (Germany)

2005-09-15

65

Toward a detailed characterization of oil adsorbates as "solid liquids".  

PubMed

Solid lipid formulation systems are used to overcome oral bioavailability problems of poorly water-soluble drugs. One promising process is the conversion of a liquid lipid system in a free flowing powder by use of adsorbing excipients. The aim of this study was the detailed characterization of solid-liquid interactions in oil adsorbed to Fujicalin and Neusilin which were manufactured by means of dual asymmetric centrifugation or conventional mortar/pestle blending. The adsorption strength of the excipients was investigated by Benchtop-NMR and ESR spectroscopy revealing the highest adsorption power for the Neusilin products. The adsorbate production methods as well as the storage of the excipients impact their adsorption properties. Environmental scanning electron microscopy (ESEM) and confocal laser scanning microscopy (CLSM) show that dual asymmetric centrifugation leads to a smoothing of the particle surface, whereas the mortar/pestle blending results in an uneven surface and particle destruction. The oil distribution at the particles is inhomogeneous for both production methods. The micropolarity of the adsorbed oil was investigated by ESR spectroscopy and multispectral fluorescence imaging. The adsorbing process on Neusilin leads to an increased micropolarity of the oil component. The release of the oil component in aqueous media could be verified by Benchtop-NMR and multispectral fluorescence imaging. PMID:23275113

Kutza, Claudia; Metz, Hendrik; Kutza, Johannes; Syrowatka, Frank; Mäder, Karsten

2013-05-01

66

Interaction of Porosity with a Planar Solid/Liquid Interface  

NASA Technical Reports Server (NTRS)

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.

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

2004-01-01

67

Final Report: Thermal Conductance of Solid-Liquid Interfaces  

SciTech Connect

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.

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

2006-05-31

68

Interaction of Porosity with a Planar Solid/Liquid Interface  

NASA Technical Reports Server (NTRS)

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.

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

2002-01-01

69

Selection of surfactants for stable paraffin-in-water dispersions, undergoing solid-liquid transition of the dispersed particles.  

PubMed

A new experimental procedure is proposed for express evaluation of the coalescence stability of dispersions, in which the dispersed particles undergo solid-liquid phase transition. The procedure includes centrifugation of the dispersion concurrently with the phase transition of the particles and allows precise quantification of dispersion stability in terms of a critical pressure, at which the coalescence between the dispersed particles/drops takes place. The method is applied for studying the effects of surfactant type and concentration on the stability of paraffin-in-water dispersions, which have potential application in energy storage and transportation systems. Several types of water-soluble surfactants (anionic, nonionic, and polymeric) are compared, whereas hexadecane or tetradecane is used as a dispersed phase. Most of the studied individual surfactants are found to be inefficient stabilizers (except for the nonionic Tween 40 and Tween 60). However, the dispersion stability increases significantly after the addition of appropriate cosurfactants, such as hexadecanol, Brij 52, or cocoamidopropyl betaine. Surfactants and cosurfactants with longer hydrophobic tails are better stabilizers than those with shorter tails. The obtained results are discussed from the viewpoint of the mechanisms of particle/drop coalescence during the solid-liquid-phase transition. The consistency and the undercooling temperatures of the studied dispersions are also discussed, because these properties are important for their practical applications. The proposed procedure for evaluation of dispersion stability and some of the conclusions could be relevant to food emulsions, in which dispersed fat particles undergo solid-liquid-phase transition of similar type. PMID:16584227

Golemanov, Konstantin; Tcholakova, Slavka; Denkov, Nikolai D; Gurkov, Theodor

2006-04-11

70

Solid-liquid transition in polydisperse Lennard-Jones systems.  

PubMed

We study melting of a face-centered crystalline solid consisting of polydisperse Lennard-Jones spheres with Gaussian polydispersity in size. The phase diagram reproduces the existence of a nearly temperature invariant terminal polydispersity (?(t) =/~ 0.11), with no signature of reentrant melting. The absence of reentrant melting can be attributed to the influence of the attractive part of the potential upon melting. We find that at terminal polydispersity the fractional density change approaches zero, which seems to arise from vanishingly small compressibility of the disordered phase. At constant temperature and volume fraction the system undergoes a sharp transition from crystalline solid to the disordered amorphous or fluid state with increasing polydispersity. This has been quantified by second- and third-order rotational invariant bond orientational order, as well as by the average inherent structure energy. The translational order parameter also indicates a similar sharp structural change at ? =/~ 0.09 in case of T(*) = 1.0, ? = 0.58. The free energy calculation further supports the sharp nature of the transition. The third-order rotationally invariant bond order shows that with increasing polydispersity, the local cluster favors a more icosahedral arrangement and the system loses its local crystalline symmetry. Interestingly, the value of structure factor S(k) of the amorphous phase at ? =/~ 0.10 (just beyond the solid-liquid transition density at T(*) = 1) becomes 2.75, which is below the value of 2.85 required for freezing given by the empirical Hansen-Verlet rule of crystallization, well known in the theory of freezing. PMID:24032772

Sarkar, Sarmistha; Biswas, Rajib; Santra, Mantu; Bagchi, Biman

2013-08-01

71

Solid-liquid transition in polydisperse Lennard-Jones systems  

NASA Astrophysics Data System (ADS)

We study melting of a face-centered crystalline solid consisting of polydisperse Lennard-Jones spheres with Gaussian polydispersity in size. The phase diagram reproduces the existence of a nearly temperature invariant terminal polydispersity (?t ? 0.11), with no signature of reentrant melting. The absence of reentrant melting can be attributed to the influence of the attractive part of the potential upon melting. We find that at terminal polydispersity the fractional density change approaches zero, which seems to arise from vanishingly small compressibility of the disordered phase. At constant temperature and volume fraction the system undergoes a sharp transition from crystalline solid to the disordered amorphous or fluid state with increasing polydispersity. This has been quantified by second- and third-order rotational invariant bond orientational order, as well as by the average inherent structure energy. The translational order parameter also indicates a similar sharp structural change at ? ? 0.09 in case of T* = 1.0, ? = 0.58. The free energy calculation further supports the sharp nature of the transition. The third-order rotationally invariant bond order shows that with increasing polydispersity, the local cluster favors a more icosahedral arrangement and the system loses its local crystalline symmetry. Interestingly, the value of structure factor S(k) of the amorphous phase at ? ? 0.10 (just beyond the solid-liquid transition density at T* = 1) becomes 2.75, which is below the value of 2.85 required for freezing given by the empirical Hansen-Verlet rule of crystallization, well known in the theory of freezing.

Sarkar, Sarmistha; Biswas, Rajib; Santra, Mantu; Bagchi, Biman

2013-08-01

72

Quasi-two-dimensional equilibrium solid/liquid interface of colloids at low osmotic pressure  

NASA Astrophysics Data System (ADS)

Solid/liquid interface is very essential for nucleation and the crystal growth process. In the present paper, we present a new method to prepare the crystal-fluid interface of colloidal hard spheres by evaporation in microchannel, which is a good candidate as a model system for the investigation of solid/liquid interface. In the system, the quasi-equilibrium colloidal solid/liquid interface is obtained at low osmotic pressure controllable by evaporation. The results show a dynamical broadening amorphous region near the solid/liquid interface. The crystal growth process in the dynamical broadening region depends on the competition between the attaching kinetics and the supersaturation related to the volume fraction. The results agree with previous investigations.

Wang, Zhijun; Wang, Jincheng; Wang, Lilin; Li, Junjie; Zhou, Yaohe

2014-01-01

73

The solid-liquid surface tension at a helium\\/cesium interface  

Microsoft Academic Search

The existence of a wetting transition for helium adsorbed on cesium provides an experimental opportunity to investigate the solid-liquid surface tension. We have extracted the temperature dependence of the solid-liquid surface tension at the4He\\/Cs interface from our earlier measurements of the wetting temperature of pure4He on thin layers of cesium overlaying gold. More recently we have measured the wetting temperature

J. E. Rutledge; D. Ross; P. Taborek

1995-01-01

74

Vertical System Integration by Using Inter-Chip Vias and Solid-Liquid Interdiffusion Bonding  

Microsoft Academic Search

A new approach for 3D system integration, called Inter Chip Via-Solid Liquid Interdiffusion (ICV-SLID) is introduced. This is a new chip-to-wafer stacking technology which combines the advantages of the Inter Chip Via (ICV) process and the solid-liquid-interdiffusion technique (SLID) of copper and tin. The fully modular ICV-SLID concept allows the formation of multiple device stacks. A test chip was designed

Armin Klumpp; Reinhard Merkel; Peter Ramm; Josef Weber; Robert Wieland

2004-01-01

75

Solid-liquid phase equilibrium for binary Lennard-Jones mixtures  

Microsoft Academic Search

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

Monica R. Hitchcock; Carol K. Hall

1999-01-01

76

Biodegradation of biphenyl in a solid–liquid two-phase partitioning bioreactor  

Microsoft Academic Search

Biphenyl was successfully degraded by Burkholderia xenovorans LB400, initially described as Pseudomonas sp. LB400, in a solid–liquid two-phase partitioning bioreactor (TPPB). Solid–liquid TPPBs are comprised of an aqueous, cell containing phase, and a solid polymeric phase that partitions toxic and\\/or poorly soluble substrates (in this case biphenyl) based on maintaining a thermodynamic equilibrium. The employed polymer was Hytrel™, a thermoplastic

Lars Rehmann; Andrew J. Daugulis

2007-01-01

77

Fluctuations during freezing and melting at the solid-liquid interface of xenon  

Microsoft Academic Search

Dynamic light-scattering experiments have been performed to study the dynamical processes at the solid-liquid interface during freezing and melting on a mesoscopic length scale. Xenon has been used as a model substance because it forms a simple liquid, and van der Waals forces are the only interactions between the atoms. A solid-liquid interface is formed by melting a sphere with

S. di Nardo; J. H. Bilgram

1995-01-01

78

Solid–liquid phase equilibrium for binary Lennard-Jones mixtures  

Microsoft Academic Search

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

Monica R. Hitchcock; Carol K. Hall

1999-01-01

79

NUMERICAL SIMULATION OF LAMINAR SOLID-LIQUID TWO-PHASE FLOW IN STIRRED TANKS  

Microsoft Academic Search

Laminar flow of solid-liquid suspension has been rarely reported in the literature. In this article, the laminar solid-liquid two-phase flow in a lab-scale stirred tank is measured with digital particle image velocimetry (DPIV) and numerically simulated with the improved inner-outer iterative method. The simulation results show good agreement with the present data. In the range of low solid volume concentration

Long Fan; Zai-Sha Mao; Chao Yang; Yundong Wang

2007-01-01

80

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

NASA Astrophysics Data System (ADS)

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.

Feng, Haijun; Zhou, Jian; Qian, Yu

2011-10-01

81

Modeling the solid-liquid phase transition in saturated triglycerides  

NASA Astrophysics Data System (ADS)

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 ?H. 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 ?H 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 ?H 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 bands in the temperature range of -20 °C<=T<=90 °C. The experimental results were in accord with the predictions of the h-Y model and support the proposal of Corkery et al. [Langmuir 23, 7241 (2007)] that the liquid state is made up of molecules that are each, on average, in a Y conformation. Finally, we carried out computer simulations of minimal-model TLs in the liquid phase, and concluded that although the individual TL molecules are, on average, Y conformers, long-range discotic order is unlikely to exist.

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

2010-02-01

82

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

NASA Astrophysics Data System (ADS)

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.

Lindner, Gerhard

2008-06-01

83

Combining molecular dynamics simulation and transition state theory to evaluate solid-liquid interfacial friction in carbon nanotube membranes.  

PubMed

A molecular dynamics (MD) methodology based on Eyring theory of reaction rates is proposed for investigating solid-liquid interfacial properties crucial to the development of many nanotechnology applications. The method involves the calculation of activation energy required for the flow process directly from the MD trajectory information. We have applied this methodology to study the behavior of water in hydrophobic confinement in carbon nanotubes (CNTs) and also between graphene sheets. In the case of confined water molecules in CNTs and between graphene sheets the degree of confinement and curvature effects were found to have more influence on the solid-liquid interfacial friction, with almost negligible friction below a certain characteristic dimension in both the cases. This behavior of confined and unconfined water molecules is explained on the basis of molecular interactions and subsequent changes in the activation energy. Analysis based on this method also revealed that a finite amount of friction does exist at the channel entry and exit region. This could limit the flow of liquid molecules through the nanochannels and hence needs to be taken into account in the design of nanofluidic devices. PMID:23004743

Babu, Jeetu S; Sathian, Sarith P

2012-05-01

84

Combining molecular dynamics simulation and transition state theory to evaluate solid-liquid interfacial friction in carbon nanotube membranes  

NASA Astrophysics Data System (ADS)

A molecular dynamics (MD) methodology based on Eyring theory of reaction rates is proposed for investigating solid-liquid interfacial properties crucial to the development of many nanotechnology applications. The method involves the calculation of activation energy required for the flow process directly from the MD trajectory information. We have applied this methodology to study the behavior of water in hydrophobic confinement in carbon nanotubes (CNTs) and also between graphene sheets. In the case of confined water molecules in CNTs and between graphene sheets the degree of confinement and curvature effects were found to have more influence on the solid-liquid interfacial friction, with almost negligible friction below a certain characteristic dimension in both the cases. This behavior of confined and unconfined water molecules is explained on the basis of molecular interactions and subsequent changes in the activation energy. Analysis based on this method also revealed that a finite amount of friction does exist at the channel entry and exit region. This could limit the flow of liquid molecules through the nanochannels and hence needs to be taken into account in the design of nanofluidic devices.

Babu, Jeetu S.; Sathian, Sarith P.

2012-05-01

85

Analysis of capacitive force acting on a cantilever tip at solid/liquid interfaces  

NASA Astrophysics Data System (ADS)

Dielectric properties of biomolecules or biomembranes are directly related to their structures and biological activities. Capacitance force microscopy based on the cantilever deflection detection is a useful scanning probe technique that can map local dielectric constant. Here we report measurements and analysis of the capacitive force acting on a cantilever tip at solid/liquid interfaces induced by application of an alternating voltage to explore the feasibility of the measurements of local dielectric constant by the voltage modulation technique in aqueous solutions. The results presented here suggest that the local dielectric constant measurements by the conventional voltage modulation technique are basically possible even in polar liquid media. However, the cantilever deflection is not only induced by the electrostatic force, but also by the surface stress, which does not include the local dielectric information. Moreover, since the voltage applied between the tip and sample are divided by the electric double layer and the bulk polar liquid, the capacitive force acting on the apex of the tip are strongly attenuated. For these reasons, the lateral resolution in the local dielectric constant measurements is expected to be deteriorated in polar liquid media depending on the magnitude of dielectric response. Finally, we present the criteria for local dielectric constant measurements with a high lateral resolution in polar liquid media.

Umeda, Ken-ichi; Kobayashi, Kei; Oyabu, Noriaki; Hirata, Yoshiki; Matsushige, Kazumi; Yamada, Hirofumi

2013-04-01

86

Probing simultaneously the volume and surface structure of nanospheres adsorbed at a solid-liquid interface by GISANS  

Microsoft Academic Search

We demonstrate in this paper the possibilities offered by \\u000a Grazing Incidence Small Angle Neutron Scattering (GISANS) for the study of \\u000a solid\\/liquid interfaces. We present experimental results obtained by \\u000a Specular Neutron Reflectivity (SNR) and GISANS on a model system made of \\u000a silica nanospheres adsorbed on a silicon wafer by electrostatic interactions \\u000a both at solid\\/air interface and solid\\/liquid interfaces. At the solid\\/liquid

F. Cousin; J. Jestin; G. Chaboussant; S. Gautrot; A. Menelle; F. Ott

2009-01-01

87

Numerical simulations of solid-liquid stirred tank with an improved Intermig impeller  

NASA Astrophysics Data System (ADS)

Numerical simulations of solid-liquid mixing in a stirred tank with an improved Intermig impeller were performed by adopting standard ?-? turbulence model coupled with Eulerian granular multiphase model. An unsteady sliding mesh approach was used to simulate the impeller rotation. The flow field, solids hold-up and power consumptions were investigated in the solid-liquid mixing system. Compared to the standard Intermig impeller, the improved Intermig impeller coupled with the special sloped baffle could promote the fluid circulation, creating better solid suspension and consuming lesser power.

Zhao, Hongliang; Zhang, Ting'an; Liu, Yan; Zhang, Zimu; Zhang, Chao

2013-06-01

88

Polyethylene glycol immobilized on silica gel as a new solid–liquid phase-transfer catalyst for regioselective azidolysis of epoxides in water: An efficient route to 1,2-azido alcohols  

Microsoft Academic Search

Polyethylene glycol, a polymer widely used for biomedical applications and in supported synthesis, was easily immobilized on silica gel and used as a new solid–liquid phase-transfer catalyst. It is proved to be an efficient heterogeneous catalyst for regioselective ring opening of epoxide by azide ion in water to give azidohydrine in excellent yield under mild reaction conditions. The polymeric catalyst

Ali-Reza Kiasat; Maryam Zayadi

2008-01-01

89

Solid–liquid equilibria in mixtures of molten salt hydrates for the design of heat storage materials  

Microsoft Academic Search

Enthalpy of melting can be used to store heat in a simple way for time periods of hours and days. Knowledge of the solid-liquid equilibria represents the most important pre- sumption for systematic evaluations of the suitability of hydrated salt mixtures. In this paper, two approaches for predicting solid-liquid equilibria in ternary or higher component systems are discussed using the

W. Voigt; D. Zeng

2002-01-01

90

A Numerical Method for Multiphase Incompressible Thermal Flows with Solid-Liquid and Liquid-Vapor Phase Transformations  

Microsoft Academic Search

A numerical method for multiphase incompressible thermal flows with solid–liquid and liquid–vapor phase transformations is presented. The flow is mainly driven by thermocapillary force and vaporization. Based on the level set method and mixture continuum model, a set of governing equations valid for solid, liquid, and vapor phases is derived, considering phase boundary conditions as source terms in the transport

Hyungson Ki; Pravansu S. Mohanty; Jyoti Mazumder

2005-01-01

91

Capillarylike fluctuations of a solid-liquid interface in a noncohesive granular system.  

PubMed

One of the most noticeable collective motion of noncohesive granular matter is clustering under certain conditions. In particular, when a quasi-two-dimensional monolayer of monodispersed noncohesive particles is vertically vibrated, a solid-liquid-like transition occurs when the driving amplitude exceeds a critical value. Here the physical mechanism underlying particle clustering relies on the strong interactions mediated by grain collisions, rather than on grain-grain cohesive forces. In average, the solid cluster resembles a drop, with a striking circular shape. We experimentally investigate the coarse-grained solid-liquid interface fluctuations, which are characterized through the static and dynamic correlation functions in the Fourier space. These fluctuations turn out to be well described by the capillary wave theory, which allows us to measure the solid-liquid interface surface tension and mobility once the granular "thermal" kinetic energy is determined. Despite that the system is strongly out of equilibrium and that the granular temperature is not uniform, there is energy equipartition at the solid-liquid interface, for a relatively large range of angular wave numbers. Furthermore, both surface tension and mobility are consistent with a simple order of magnitude estimation considering the characteristic energy, length, and time scales, which is very similar to what can be done for atomic systems. PMID:23679358

Luu, Li-Hua; Castillo, Gustavo; Mujica, Nicolás; Soto, Rodrigo

2013-04-01

92

Capillarylike fluctuations of a solid-liquid interface in a noncohesive granular system  

NASA Astrophysics Data System (ADS)

One of the most noticeable collective motion of noncohesive granular matter is clustering under certain conditions. In particular, when a quasi-two-dimensional monolayer of monodispersed noncohesive particles is vertically vibrated, a solid-liquid-like transition occurs when the driving amplitude exceeds a critical value. Here the physical mechanism underlying particle clustering relies on the strong interactions mediated by grain collisions, rather than on grain-grain cohesive forces. In average, the solid cluster resembles a drop, with a striking circular shape. We experimentally investigate the coarse-grained solid-liquid interface fluctuations, which are characterized through the static and dynamic correlation functions in the Fourier space. These fluctuations turn out to be well described by the capillary wave theory, which allows us to measure the solid-liquid interface surface tension and mobility once the granular “thermal” kinetic energy is determined. Despite that the system is strongly out of equilibrium and that the granular temperature is not uniform, there is energy equipartition at the solid-liquid interface, for a relatively large range of angular wave numbers. Furthermore, both surface tension and mobility are consistent with a simple order of magnitude estimation considering the characteristic energy, length, and time scales, which is very similar to what can be done for atomic systems.

Luu, Li-Hua; Castillo, Gustavo; Mujica, Nicolás; Soto, Rodrigo

2013-04-01

93

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

ERIC Educational Resources Information Center

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…

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

2007-01-01

94

NUTRIENT RECOVERY BY SOLID-LIQUID SEPARATION AND METHANE PRODUCTIVITY OF SOLIDS  

Microsoft Academic Search

Solid-liquid separation of manure is a method to produce nutrient and dry matter rich fractions with higher volumetric methane potential than that of the original liquid manure. Centrifugation and chemical precipitation and flocculation are efficient options for such separation. Centrifugation efficiency depends on factors such as manure type, G-force, and dewatering volume, while chemical precipitation and flocculation depend on the

H. B. Møller; J. D. Hansen; C. A. G. Sørensen

95

Pulsed electric field treatment for solid–liquid extraction of red beetroot pigment  

Microsoft Academic Search

Extractability of red pigment from red beetroot was investigated using pulsed electric field (PEF) treated tissue in a solid–liquid extraction process. Thin disks of the tissue were subjected to PEF at different intensities and, 3–4 min after the treatment, the release of red pigment and ionic species into an isotonic solution was measured in situ using a spectrophotometer and a

Mustafa Fincan; Francesca DeVito; Petr Dejmek

2004-01-01

96

A Structural Model for the Solid-Liquid Interface in Monatomic Systems.  

National Technical Information Service (NTIS)

A structural model for the solid-liquid interface has been developed by applying the construction rules for the liquid to the boundary condition of a crystal plane. In particular, an interface has been created between a dense random packing of hard sphere...

F. Spaepen

1975-01-01

97

Measurement of solid--liquid interface temperature during pulsed excimer laser melting of polycrystalline silicon films  

SciTech Connect

A nanosecond time resolution pyrometer has been developed for measuring the transient temperature of thin polycrystalline silicon ([ital p]-Si) films irradiated by a pulsed excimer laser. The sample design structure and material optical properties allow direct measurement of the temperature at the solid--liquid phase change interface.

Xu, X.; Grigoropoulos, C.P. (Department of Mechanical Engineering, University of California, Berkeley, California 94720 (United States)); Russo, R.E. (Energy and Environmental Division, Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States))

1994-10-03

98

Adsorption\\/aggregation of surfactants and their mixtures at solid–liquid interfaces  

Microsoft Academic Search

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

P. Somasundaran; L. Huang

2000-01-01

99

Solid–liquid extraction of protopine from Fumaria officinalis L.—Experimental study and process optimization  

Microsoft Academic Search

Optimization of the protopine batch extraction from Fumaria officinalis was studied by experimental design. Several parameters were first studied in order to measure their influence on batch extraction thus enabling to choose the most accurate model. A response surface method design that allows investigating the simultaneous variations of the three main parameters (percentage of ethanol in solvent, temperature, solid–liquid weight

Lovasoa Rakotondramasy-Rabesiaka; Jean-Louis Havet; Catherine Porte; Henri Fauduet

2008-01-01

100

Adhesion of Leptospira at a solid-liquid interface: a model  

Microsoft Academic Search

Two strains of the saprophytic Leptospira biflexa serovar patoc display reversible and irreversible adhesion at a solid-liquid interface. Both forms of adhesion are enhanced in the presence of 20 µM carbonyl cyanide metachlorophenyl hydrazone (CCCP), an uncoupler which inhibits motility of the bacteria. Microscopic observations also indicated that motility may have a role in adhesion as only actively motile organisms

Bruce Kefford; Kevin C. Marshall

1984-01-01

101

Atomistic Simulations for computing solid liquid interface properties of the Al-Mg system  

Microsoft Academic Search

Crystal-melt interface properties and their associated anisotropies playa crucial role during solidification in controlling the nucleation, crystallization rate and growth morphology. There are two solid-liquid interfacial (SLI) properties affecting the dendritic microstructures that form in the crystallization process and the SLI properties are interfacial free energy (?) and kinetic coefficient (?) . In this research work, atomic scale simulation techniques,

Jahidur Rahman

2009-01-01

102

Different gastric, pancreatic, and biliary responses to solid-liquid or homogenized meals  

Microsoft Academic Search

We have compared responses to an ordinary solid-liquid (S) meal and to a homogenized (H) meal of identical composition (sirloin steak, bread, butter, ice cream with chocolate syrup, and water) by measuring simultaneously postprandial gastric, pancreatic, and biliary functions by marker-perfusion techniques. Responses to each (S or H) meals differed strikingly both in magnitude and pattern. S meals elicited a

Juan-R. Malagelada; Vay L. W. Go; W. H. J. Summerskill

1979-01-01

103

Simulation of solid—liquid flows in a vertical pipe by a collision model  

Microsoft Academic Search

Two-dimensional simulation of solid—liquid flows in a vertical pipe was carried out. Trajectories of the particles were obtained using the Lagrangian method with a deterministic interparticle collision model and irregular bouncing of particles off the pipe wall. Local mean velocities of the liquid phase were simulated from the equations of continuity and motion by the SIMPLE scheme taking into account

K. Asakura; T. Asari; I. Nakajima

1997-01-01

104

Comparison of Kinetic and Diffusional Models for Solid-Liquid Reactions.  

National Technical Information Service (NTIS)

A comparison of the kinetic and diffusional models for solid-liquid reactions occuring in a spherical particle is presented. The similarities and differences of the unreacted-core shrinking model and the homogeneous model are examined in light of the rate...

C. Y. Wen

1967-01-01

105

Dynamic rearrangement of bilayers of porphyrin hetero-dimers at a solid/liquid interface.  

PubMed

STM reveals that self-assembled bilayers of covalently linked Cu-Mn porphyrin dimers can dynamically rearrange at a solid/liquid interface by rapid exchange of molecules between the bilayer and the supernatant, or via a slower two-dimensional translation of the whole top layer. PMID:24871585

Lensen, Dennis; Habets, Thomas; Elemans, Johannes A A W

2014-06-12

106

Dynamics of colloidal pitch adsorption at the solid–liquid interface by surface plasmon resonance  

Microsoft Academic Search

This study has two objectives. The first is to investigate the direct adsorption of pitch on pulp fibres as a papermaking strategy. The second objective is to evaluate the potential of surface plasmon resonance (SPR) to quantify the adsorption of polydisperse colloids at the solid–liquid interface. The affinity of colloidal pitch for carboxyl methyl dextran (CMD) surfaces was studied by

Gerard Murray; Karen Stack; Douglas S. McLean; Wei Shen; Gil Garnier

2009-01-01

107

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

ERIC Educational Resources Information Center

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…

2000

108

Solid–liquid extraction of andrographolide from plants—experimental study, kinetic reaction and model  

Microsoft Academic Search

Solid–liquid extraction is performed from leaves and stems of Andrographis paniculata in ethanol–water solvent, in order to obtain andrographolide. The first part of this work concerns the acquisition of the raw plant geometric and physicochemical characteristics. Then batch experiments are done in order to study the influences of the operating parameters (temperature, nature of the solvent and particles size). Furthermore,

R. Wongkittipong; L. Prat; S. Damronglerd; C. Gourdon

2004-01-01

109

Chromosaponin I Specifically Interacts with AUX1 Protein in Regulating the Gravitropic Response of Arabidopsis Roots  

Microsoft Academic Search

We have found that chromosaponin I (CSI), a g-pyronyl-triterpenoid saponin isolated from pea (Pisum sativum L. cv Alaska), specifically interacts with AUX1 protein in regulating the gravitropic response of Arabidopsis roots. Application of 60 mm CSI disrupts the vertically oriented elongation of wild-type roots grown on agar plates but orients the elongation of agravitropic mutant aux1-7 roots toward the gravity.

Abidur Rahman; Arifa Ahamed; Taisaku Amakawa; Nobuharu Goto; Seiji Tsurumi

2001-01-01

110

Problemes aux limites en theorie des distributions  

Microsoft Academic Search

Résumé  Etude de la méthode des potentiels pour résoudre des problèmes aux limites relatifs à certains opérateurs différentiels. Résolution\\u000a et discussion des problèmes aux limites pour un système diffèrentiel elliptique lorsque les données sont des distributions\\u000a (le problème étant elliptique à droite ou à gauche).

Paul Krée

1969-01-01

111

Behavior of aluminum shear modulus in solid-liquid mixed phase: Estimation with percolation theory  

NASA Astrophysics Data System (ADS)

The variation of aluminum shear modulus with the melting-mass fraction in the solid-liquid mixed phase has been estimated by the percolation theory. With the total number of calculated sites from 0.125×106 to 8.0×106, it is shown that there are two critical points corresponding to the melting-mass fraction 0.313 and 0.687, respectively. At the critical point 0.313, the longitudinal sound velocity begins to attenuate to bulk sound velocity and completely attenuates to bulk sound velocity at the critical point 0.687. This is in accord with previous independent and our sound velocity data of aluminum in the solid-liquid phase, and suggests a different interpretation of shock sound speed data for melt mass fraction.

Ran, Xianwen; Yu, Yuying; Tan, Hua; Tang, Wenhui

2008-05-01

112

Picosecond ultrasonic study of phonon reflection from solid-liquid interfaces  

SciTech Connect

We have studied the reflection of longitudinal-acoustic phonons with frequencies between 100 and 300 GHz from solid-liquid interfaces using a picosecond ultrasonic technique. Acoustic phonons were generated by absorption of a picosecond light pulse in a metal film. After propagating through a dielectric layer, the phonons were reflected at the solid-liquid interface. We have measured the reflection coefficient at a series of interfaces between dielectric solids and organic liquids for temperatures from 265 to 300 K. The reflection of 205 GHz phonons was also measured between aluminum and liquid argon and nitrogen. The experimental results were compared with the predictions of the classical acoustic-mismatch model. {copyright} {ital 1997} {ital The American Physical Society}

Tas, G.; Maris, H.J. [Department of Physics, Brown University, Providence, Rhode Island 02912 (United States)] [Department of Physics, Brown University, Providence, Rhode Island 02912 (United States)

1997-01-01

113

[Anaerobic biodegradation of pentachlorophenol (PCP) in solid-liquid phase of contaminated sediment slurry].  

PubMed

The study showed that after inoculating 10 g x kg(-1) anaerobic dechlorinated granular sludge (ADGS) for 31 days, the biodegradation rate of pentachlorophenol (PCP) in solid-liquid phase of contaminated sediment slurry was up to 98.9%, with an average of 8.0 mg x kg(-1) x d(-1), while that of the control was only 4.4 mg x kg(-1) x d(-1). As the regulation factors in slurry remediation, organic solvent, co-substrate and surfactant had different effects on PCP degradation. The addition of ethanol could enhance the desorption and degradation of PCP, the degradation rate being up to 54.3 mg x kg(-1) d(-1) within 4 days, while the addition of co-substrate and non-ionic surfactant EGME (ethylene glycol monobutyl-ether) inhibited the PCP degradation in solid-liquid phase of slurry. PMID:16011167

Tang, Quan; Xu, Xiangyang; Zhu, Youwei

2005-04-01

114

Interfacial plasmon at a singular solid-liquid interface in a partially molten aluminum alloy  

NASA Astrophysics Data System (ADS)

Nanoplasmonics is an important emerging research area in technologies, such as energy conversion using photovoltaic devices and hydrogen sensing using Pd nanoparticles. So far, plasmon excitations are only known to exist at the interface between two different dielectric media, such as two solids or at solid-vacuum surfaces. There has been no evidence for the presence of a plasmon at a solid-liquid interface. This paper presents results on the existence and nature of the plasmon resonance between a semiconducting solid and a liquid metal, investigated in a transmission electron microscope having sub-eV and sub-Å resolutions. The results are compared with calculations of the plasmon based on dielectric theory and are corroborated with energy-filtered imaging analyses. The unique plasmon resonance observed at the solid-liquid interface provides new insight into the behavior of plasmons in research areas from biomedical imaging to liquid crystals, including the technologies mentioned above.

Palanisamy, Prakash; Sigle, Wilfried; Howe, James M.

2012-05-01

115

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

PubMed

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

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

2013-05-01

116

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

SciTech Connect

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.

Kabadi, V.N.; Ilias, S.

1992-01-01

117

Effect of thermal convection on the shape of a solid-liquid interface  

NASA Astrophysics Data System (ADS)

The effect of thermal convection on the shape of solid-liquid interface was investigated in experiments conducted in a transparent Bridgman-type directional solidification furnace. The relationship was numerically modeled using a standard 2D finite-difference approach, with the solid-liquid deformable interface approximated by a blocking-off technique. The directional solidification furnace was used with pure succinonitrile (which is also transparent) contained in a long square ampoule made of borosilicate glass. With the furnace in the vertical configuration, a flat interface was observed, in agreement with the model. On the other hand, a highly distorted interface was obtained in the horizontal configuration; the numerical results showed a strong recirculating cell in front of the interface due to natural thermal convection. The results indicate that thermal convection is responsible for the interface distortion.

Mennetrier, C.; Chopra, M. A.; de Groh, H. C., III

118

Energy efficient thermal management of electronic components using solid-liquid phase change materials  

Microsoft Academic Search

Energy efficiency is becoming a key issue in the development of thermal management devices. To this end, thermal performance of plate fin and pin fin heat sinks incorporating a solid-liquid phase change material (PCM) has been evaluated, under periodic power inputs simulating actual heating conditions. Experiments were performed using Wood's metal (50Bi\\/27Pb\\/13Sn\\/10Cd, melting point: 70.0°C) under forced convection in a

Dong-won Yoo; Yogendra K. Joshi

2004-01-01

119

Silver dendritic nanostructures formed at the solid\\/liquid interface via electroless deposition  

Microsoft Academic Search

Silver dendritic nanostructures and nanoplates were prepared at the solid\\/liquid interfaces via electroless deposition. Langmuir monolayers of 5,10,15,20-tetra-4-oxy(2-stearic acid) phenyl porphyrin (TSPP) and arachidic acid (AA) were formed at the air\\/AgNO3 aqueous solution interface. These nanostructures were produced when carbon-coated copper grids were covered on the Langmuir monolayers at lower (<20°C) and higher (20–50°C) temperature, respectively, and the branches are

Hui-Ping Ding; Guo-Qing Xin; Kuang-Cai Chen; Maoli Zhang; Qingyun Liu; Jingcheng Hao; Hong-Guo Liu

2010-01-01

120

Electron Beam Design and Calibration for the Solid\\/Liquid Lithium Divertor Experiment  

Microsoft Academic Search

An electron beam has been developed as part of the Solid\\/Liquid Lithium Divertor Experiment (SLiDE) at the University of Illinois at Urbana-Champaign. The purpose of the SLiDE apparatus is to examine the motion of liquid lithium under fusion relevant heat loads and magnetic fields. To mimic the heat fluxes present in the divertor of a fusion machine, a linear sheet

Michael Jaworski; R. Flauta; T. K. Gray; J. Kim; C. Y. Lau; M. B. Lee; M. J. Neumann; V. Surla; D. N. Ruzic

2008-01-01

121

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

Microsoft Academic Search

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

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

1987-01-01

122

Optimization of solid–liquid extraction of phytochemicals from Garcinia indica Choisy by response surface methodology  

Microsoft Academic Search

A central composite rotatable design was employed to study the effect of ultrasound assisted extraction conditions namely sonication amplitude (10–90%), sonication cycle (0.1–1.0s?1), solid–liquid ratio (2–10) and extraction time (5–35min) on the total anthocyanin extraction from Garcinia indica Choisy. Overall extractions of total anthocyanin, acidity and antioxidant activity were considered as response variables. The significant (p<0.05) response surface models with

Chetan A. Nayak; Navin K. Rastogi

123

Acoustic Monitor for Solid-Liquid Slurries Measurements at Low Weight Fractions  

Microsoft Academic Search

We have developed an acoustic monitor for accurate, real-time measurement of solids concentration in solid-liquid (S-L) and solid-gas-liquid (S-G-L) slurries at low solids weight percent (0.5 to 10 wt. %). The Syracuse Acoustic Monitor (SAM) has potential for slurry transport monitoring, processing stream monitoring, and process control capabilities for nuclear wastes treatment throughout the DOE complex. The SAM is based

Lawrence L. Tavlarides; Oleksandr Shcherbakov; Eric Dievendorf; Ashok Sangini

2003-01-01

124

Phase-behavior and solid–liquid phase-transfer catalytic activity of tetrabutylammonium bromide  

Microsoft Academic Search

The addition of water to tetrabutylammonium bromide (TBABr)\\/benzene\\/sodium bromide ternary component systems induced the separation of TBABr-rich liquid phase (L phase) prior to the appearance of an aqueous phase (W phase). The L phase was assumed to be a bicontinuous phase similar to a microemulsion based on the phase composition. TBABr catalyzed the “solid–liquid” phase-transfer reaction of decyl methanesulfonate with

Noritaka Ohtani; Tsuyoshi Yamashita; Tomoaki Ohta; Yasuhiro Hosoda

2005-01-01

125

Solid–liquid extraction of caffeine from tea waste using battery type extractor: Process optimization  

Microsoft Academic Search

This article deals with solid–liquid extraction of caffeine from tea waste containing 2% (w\\/w) caffeine using water and chloroform as effective solvents. The extraction has been performed at isothermal conditions of 370K for water and 293K for chloroform in the battery type extraction plant including both three and five extractors connected in series. An obvious difference in extraction behavior has

Aynur Senol; Ahmet Aydin

2006-01-01

126

A New Criterion Number for the Boundary Conditions at the Solid\\/Liquid Interface in Nanoscale  

Microsoft Academic Search

A simple, but important three-atom model was proposed at the solid\\/liquid interface, leading to a new criterion number, ?, governing the boundary conditions (BCs) in nanoscale. The solid wall is considered as the face-centered-cubic (fcc) structure. The fluid is the liquid argon with the well-known LJ potential. Based on the concept, the two micro-systems have the same BCs if they

Yuxiu Li; Jinliang Xu

2006-01-01

127

Solid–liquid–solid growth mechanism of single-wall carbon nanotubes  

Microsoft Academic Search

Reasons are presented which suggest that the liquefaction of the catalytic particles is a decisive condition for formation of single wall carbon nanotubes (SWNTs) by physical synthesis techniques. It is argued that the SWNT growth mechanism is a kind of solid–liquid–solid graphitization of amorphous carbon or other imperfect carbon forms catalyzed by molten supersaturated carbon–metal nanoparticles. The assumption of low

A Gorbunov; O Jost; W Pompe; A Graff

2002-01-01

128

Controlled growth of oriented amorphous silicon nanowires via a solid–liquid–solid (SLS) mechanism  

Microsoft Academic Search

Highly oriented amorphous silicon nanowires (a-SiNWs ) were grown on Si (111). The length and diameter of oriented SiNWs are almost uniform, which are 1?m and 25nm, respectively. Different from the well-known vapor–liquid–solid (VLS) for conventional whisker growth, it was found that growth of the a-SiNWs was controlled by a solid–liquid–solid mechanism (SLS). This synthesis method is simple and controllable.

D. P Yu; Y. J Xing; Q. L Hang; H. F Yan; J Xu; Z. H Xi; S. Q Feng

2001-01-01

129

Biodegradation of a phenolic mixture in a solid–liquid two-phase partitioning bioreactor  

Microsoft Academic Search

A solid–liquid two-phase partitioning bioreactor (TPPB) in which the non-aqueous phase consisted of polymer (HYTREL) beads was used to degrade a model mixture of phenols [phenol, o-cresol, and 4-chlorophenol (4CP)] by a microbial consortium. In one set of experiments, high concentrations (850 mg l?1 of each of the three substrates) were reduced to sub-inhibitory levels within 45 min by the addition of

George P. Prpich; Andrew J. Daugulis

2006-01-01

130

A three-phase ternary model for CO 2-Solid-Liquid equilibrium at moderate pressures  

Microsoft Academic Search

In this work, we present a simple, totally predictive, three-phase modeling for systems containing CO2-solid-liquid for evaluation of cosolvents in the supercritical-fluid extraction (SCFE) of volatile matter of Brazilian mineral coals. The liquid phase is modeled by the traditional regular solution theory while the gas phase is represented by the Peng-Robinson\\/Stryjek-Vera equation of state and the heavy component is taken

Sandro R. P. da Rocha; José V. de Oliveira; Saul G. d' Ávila

1996-01-01

131

A study of the size dependence of self diffusivity across the solid-liquid transition  

Microsoft Academic Search

The present study investigates the effect of temperature-induced change of phase from face centred cubic solid to liquid on the size dependence of self diffusivity of solutes through detailed molecular dynamics simulations on binary mixtures consisting of a larger solvent and a smaller solute interacting via Lennard-Jones potential. The effect of change in density during the solid-liquid transition as well

Manju Sharma; S. Yashonath

2008-01-01

132

Interaction of iron particles with a solid-liquid interface in lead and lead alloys  

Microsoft Academic Search

The interaction of iron particles with an advancing solid-liquid interface has been examined in lead and lead alloys. In the\\u000a case of pure lead solidified with a planar interface, the particle distribution in the solid and quenched liquid was uniform,\\u000a indicating particles werenot rejected at the interface. For interfaces with a cellular and dendritic structure the particles were concentrated in

C. E. Schvezov; F. Weinberg

1985-01-01

133

A Study on Thermal Resistance over a Solid-Liquid Interface by the Molecular Dynamics Method  

Microsoft Academic Search

Through molecular dynamics simulations, it was demonstrated that a thermal resistance cannot be neglected over a solid-liquid interface when a system size is very small, i.e. the relative importance of thermal resistance of heat conduction is small. A quasi-steady non-equilibrium heat-transfer simulation was performed with the molecular dynamics method. A vapor region was sandwiched between liquid layers, which were in

Shigeo MARUYAMA; Tatsuto KIMURA

1999-01-01

134

Quantitative Measurements of Adsorbate-Adsorbate Interactions at Solid-Liquid Interfaces  

Microsoft Academic Search

The interactions between adsorbates at a solid-liquid interface were studied by video-rate STM for the case of sulfur on Cu(100) electrode surfaces in HCl solution. Quantitative data were obtained by analyzing the Sad dimer dynamics within the surrounding c(2×2)-Cl adlattice as well as the adsorbate configurations. The interactions are repulsive for Sad separated by one or two lattice spacings and

A. Taranovskyy; T. Tansel; O. M. Magnussen

2010-01-01

135

Modeling of solid–liquid equilibria for systems with solid-complex phase formation  

Microsoft Academic Search

The Perturbed-Chain SAFT (PC-SAFT) equation of state (EOS) is applied to model the solid–liquid equilibria (SLE) of binary and ternary systems showing a solid-complex phase formation. Modeling results for mixtures composed of associating components, e.g. water, alcohols, phenol, bisphenol A (BPA), as well as acetamide are presented. The solid-complex phase formation is modeled as a chemical reaction between species in

Feelly Tumakaka; Igor V. Prikhodko; Gabriele Sadowski

2007-01-01

136

Quantifying metallurgical interactions in solid\\/liquid diffusion couples using differential scanning calorimetry  

Microsoft Academic Search

A novel method using differential scanning calorimetry (DSC) has been developed to quantify the interface kinetics in a solid\\/liquid diffusion couple. The Ag–Cu binary eutectic system is investigated by heating an assembly of Ag base metal and Ag–Cu eutectic foil to 800 °C and holding. The fraction of liquid remaining after various isothermal hold periods is measured by comparing the

M. L. Kuntz; S. F. Corbin; Y. Zhou

2005-01-01

137

Electrokinetic microslit experiments to analyse the charge formation at solid\\/liquid interfaces  

Microsoft Academic Search

Electrokinetic effects play an important role in microfluidics and nanofluidics. Although the related phenomena are often utilized to control fluid flow and sample transport in lab-on-a-chip devices, their dependency on the surface charges on the channel walls often remain enigmatic. This is mainly due to the lack of adequate experimental methods to analyse the electrical charging of solid\\/liquid interfaces of

Ralf Zimmermann; Toshihisa Osaki; Rüdiger Schweiß; Carsten Werner

2006-01-01

138

Measurement of solid liquid interfacial energy in the In Bi eutectic alloy at low melting temperature  

Microsoft Academic Search

The Gibbs-Thomson coefficient and solid-liquid interfacial energy of the solid In solution in equilibrium with In Bi eutectic liquid have been determined to be (1.46 ± 0.07) × 10-7 K m and (40.4 ± 4.0) × 10-3 J m-2 by observing the equilibrated grain boundary groove shapes. The grain boundary energy of the solid In solution phase has been calculated

N. Marasli; S. Akbulut; Y. Ocak; K. Keslioglu; U. Böyük; H. Kaya; E. Çadirli

2007-01-01

139

Solid-liquid phase equilibria at 727 °C in the ternary system Fe-Mg-Si  

Microsoft Academic Search

The solid-liquid phase equilibria in the Fe-Mg-Si ternary system were experimentally investigated at 727 °C by two complementary\\u000a approaches: reaction to equilibrium of Fe-Mg-Si powder mixtures and growth of reaction zones at the interface of diffusion\\u000a couples. X-ray powder diffraction, optical metallography (OM), scanning electron microscopy (SEM), and electron probe microanalysis\\u000a (EPMA) were used to characterize the phases formed in

D. Pierre; M. Peronnet; F. Bosselet; J. C. Viala; J. Bouix

2000-01-01

140

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

NASA Technical Reports Server (NTRS)

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.

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

1999-01-01

141

Photolithographic fabrication of solid-liquid core waveguides by thiol-ene chemistry  

Microsoft Academic Search

In this work we demonstrate an efficient and cleanroom compatible method for the fabrication of solid-liquid core waveguides based on nanoporous polymers. We have used thiol-ene photo-grafting to tune and pattern the hydrophilicity of an originally hydrophobic nanoporous 1, 2-polybutadiene. The generated refractive index contrast between the patterned water-filled volume and the surrounding empty hydrophobic porous polymer allows for light

Kaushal Sagar; Nimi Gopalakrishnan; Mads Brøkner Christiansen; Anders Kristensen; Sokol Ndoni

2011-01-01

142

Effect of carbonitride precipitates on the solid/liquid erosion behaviour of hardfacing alloy  

NASA Astrophysics Data System (ADS)

The present work reports the effect of carbonitride precipitates on the solid/liquid erosion behaviour of hardfacing alloy. Two kinds of Fe-Cr13-C hardfacing alloy (with and without nitrogen) were deposited on a carbon steel substrate. The microstructure of the hardfacing alloy was studied. Solid/liquid erosion tests were carried out with quartz sand particles under impact angles of 30°, impact velocity of 25 m/s for 45 min to explore the erosion behaviour of the hardfacing alloy. It is found that the erosion damages of hardfacing alloy were microcutting and impinging caused by the erosion of sand particles. Fine carbonitride precipitates can obviously refine the microstructure and make a dispersion strengthening effect on the matrix, leading to the enhancement of hardness of hardfacing alloy. In addition, lots of carbonitride precipitates can effectively protect the surface of hardfacing alloy against wearing of erosion sand particles. So the erosion resistance of hardfacing alloy could be improved significantly owing to the strengthening and protecting effect of carbonitride precipitates, and solid/liquid erosion mechanisms were found to be microcutting and impinging with shallow grooves, fine pits and tiny lips.

Yang, Ke; Yang, Qin; Bao, Yefeng

2013-11-01

143

Protein refolding by reversed micelles utilizing solid-liquid extraction technique.  

PubMed

This article reports that a reversed micellar solution is useful for refolding proteins directly from a solid source. The solubilization of denatured RNase A, which had been prepared by reprecipitation from the denaturant protein solution, into reversed micelles formulated with sodium di-2-ethylhexyl sulfosuccinate (AOT) has been investigated by a solid-liquid extraction system. This method is an alternative to the ordinary protein extraction in reversed micelles based on the liquid-liquid extraction. The solid-liquid extraction method was found to facilitate the solubilization of denatured proteins more efficiently in the reversed micellar media than the ordinary phase transfer method of liquid extraction. The refolding of denatured RNase A entrapped in reversed micelles was attained by adding a redox reagent (reduced and oxidized glutathion). Enzymatic activity of RNase A was gradually recovered with time in the reversed micelles. The denatured RNase A was completely refolded within 30 h. In addition, the efficiency of protein refolding was enhanced when reversed micelles were applied to denatured RNase A containing a higher protein concentration that, in the case of aqueous media, would lead to protein aggregation. The solid-liquid extraction technique using reversed micelles affords better scale-up advantages in the direct refolding process of insoluble protein aggregates. PMID:10099241

Hashimoto, Y; Ono, T; Goto, M; Hatton, T A

1998-03-01

144

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

SciTech Connect

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.

Das, Chandan K.; Singh, Jayant K., E-mail: jayantks@iitk.ac.in [Department of Chemical Engineering, Indian Institute of Technology Kanpur, Kanpur 208016 (India)

2013-11-07

145

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

NASA Astrophysics Data System (ADS)

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.

Das, Chandan K.; Singh, Jayant K.

2013-11-01

146

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

NASA Astrophysics Data System (ADS)

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 (?), 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 based on EIS measurement using a sensor of 8 electrodes are reported. Results have demonstrated the potential as well as revealed the challenge in the use of EIS and EITS for characterisation of particle in suspension.

Zhao, Yanlin; Wang, Mi; Yao, Jim

2014-04-01

147

Crystalline order of polymer nanoparticles over large areas at solid/liquid interfaces  

NASA Astrophysics Data System (ADS)

We report on the formation of large two-dimensional domains (about 20 cm2) of oriented and ordered structures of polystyrene particles dispersed in water at a solid/liquid interface. Gentle flow of the dispersed sample into the holder at a shear strain rate of about 0.1 s-1 caused particles at the air/latex meniscus to self-assemble in a regular structure on both solid silica or alumina surfaces. Scattering experiments show that the particle separation at the surface was the same as in the bulk and determined by repulsion arising from the charges on the particles. Close-packed planes formed parallel to the interface.

Hellsing, M. S.; Kapaklis, V.; Rennie, A. R.; Hughes, A. V.; Porcar, L.

2012-05-01

148

Synthesis of Silver Selenide Bicomponent Nanoparticles by a Novel Technique: Laser-Solid-Liquid Ablation  

NASA Astrophysics Data System (ADS)

A novel laser-solid-liquid ablation technique has been developed to synthesize Ag 2Se nanoparticles from silver nitrate and selenium powder in a mixed solvent of 2-propanol and ethylenediamine. The products were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). The XRD indicated that the products were the single phase of silver selenide. The TEM images revealed that the as-prepared Ag 2Se grains were homogeneous and spherical, and their average size was about 30 nm. This novel technique can be extended to prepare other nanoparticles of various compositions.

Jiang, Z. Y.; Huang, R. B.; Xie, S. Y.; Xie, Z. X.; Zheng, L. S.

2001-09-01

149

Vermiculite-aliphatic amine interactions at the solid\\/liquid interface: a thermodynamic approach  

Microsoft Academic Search

Polar n-alkylmonoamines of general formula H3C(CH2)\\u000a n\\u000a NH2 (n = 1, 3, 5) interacted with layered silicate vermiculite at the solid\\/liquid interface. The maximum amount of amine intercalated\\u000a (N\\u000a \\u000a f\\u000a ) inside the interlamellar space were 0.62, 0.46, and 0.38 mmol g?1, to give the following order of intercalation ethyl ? butyl ? hexylamines. The layered vermiculite solid was suspended in\\u000a deionized water and calorimetrically titrated with this

Maria G. da Fonseca; Ramon K. S. Almeida; Albaneide F. Wanderley; Ulysses V. S. Ferreira; Luiza N. H. Arakaki; José A. Simoni; Claudio Airoldi

2009-01-01

150

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

NASA Technical Reports Server (NTRS)

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.

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

1989-01-01

151

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

NASA Astrophysics Data System (ADS)

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/cm 2 was determined with a total systematic and random error less than 10%. The value of interfacial energy corresponds to 24% of the latent heat of fusion per molecule.

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

1989-12-01

152

Stir-membrane solid-liquid-liquid microextraction for the determination of parabens in human breast milk samples by ultra high performance liquid chromatography-tandem mass spectrometry.  

PubMed

In this article, stir-membrane solid-liquid-liquid microextraction (SM-SLLME) is tailored for the analysis of solid matrices and it has been evaluated for the determination of parabens in l breast milk samples. A three-phase microextraction mode was used for the extraction of the target compounds taking advantage of their acid-base properties. The unit allows the simultaneous extraction of the target compounds from the solid sample to an organic media and the subsequent transference of the analytes to an aqueous acceptor phase. The method includes the identification and quantification of the analytes by ultra high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). All the variables involved in the extraction procedure have been accurately studied and optimized. The analytes were detected and quantified using a triple quadrupole mass spectrometer (QqQ). The selection of two specific fragmentation transitions for each compound allowed simultaneous quantification and identification. The method has been analytically characterized on the basis of its linearity, sensitivity and precision. Limits of detection ranged from 0.1 to 0.2ngmL(-1) with precision better than 8%, (expressed as relative standard deviation). Relative recoveries were in the range from 91 to 106% which demonstrated the applicability of the stir-membrane solid-liquid-liquid microextraction for the proposed analytical problem. Moreover, the method has been satisfactorily applied for the determination of parabens in lyophilized breast milk samples from 10 randomly selected individuals. PMID:24935266

Rodríguez-Gómez, Rocío; Roldán-Pijuán, Mercedes; Lucena, Rafael; Cárdenas, Soledad; Zafra-Gómez, Alberto; Ballesteros, Oscar; Navalón, Alberto; Valcárcel, Miguel

2014-08-01

153

Solid-liquid equilibria and triple points of n-6 Lennard-Jones fluids.  

PubMed

Molecular dynamics simulations are reported for the solid-liquid coexistence properties of n-6 Lennard-Jones fluids, where n=12, 11, 10, 9, 8, and 7. The complete phase behavior for these systems has been obtained by combining these data with vapor-liquid simulations. The influence of n on the solid-liquid coexistence region is compared using relative density difference and miscibility gap calculations. Analytical expressions for the coexistence pressure, liquid, and solid densities as a function of temperature have been determined, which accurately reproduce the molecular simulation data. The triple point temperature, pressure, and liquid and solid densities are estimated. The triple point temperature and pressure scale with respect to 1/n, resulting in simple linear relationships that can be used to determine the pressure and temperature for the limiting infinity-6 Lennard-Jones potential. The simulation data are used to obtain parameters for the Raveche, Mountain, and Streett and Lindemann melting rules, which indicate that they are obeyed by the n-6 Lennard Jones potentials. In contrast, it is demonstrated that the Hansen-Verlet freezing rule is not valid for n-6 Lennard-Jones potentials. PMID:19895022

Ahmed, Alauddin; Sadus, Richard J

2009-11-01

154

Solid-liquid equilibria and triple points of n-6 Lennard-Jones fluids  

NASA Astrophysics Data System (ADS)

Molecular dynamics simulations are reported for the solid-liquid coexistence properties of n-6 Lennard-Jones fluids, where n=12, 11, 10, 9, 8, and 7. The complete phase behavior for these systems has been obtained by combining these data with vapor-liquid simulations. The influence of n on the solid-liquid coexistence region is compared using relative density difference and miscibility gap calculations. Analytical expressions for the coexistence pressure, liquid, and solid densities as a function of temperature have been determined, which accurately reproduce the molecular simulation data. The triple point temperature, pressure, and liquid and solid densities are estimated. The triple point temperature and pressure scale with respect to 1/n, resulting in simple linear relationships that can be used to determine the pressure and temperature for the limiting ?-6 Lennard-Jones potential. The simulation data are used to obtain parameters for the Raveché, Mountain, and Streett and Lindemann melting rules, which indicate that they are obeyed by the n-6 Lennard Jones potentials. In contrast, it is demonstrated that the Hansen-Verlet freezing rule is not valid for n-6 Lennard-Jones potentials.

Ahmed, Alauddin; Sadus, Richard J.

2009-11-01

155

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

SciTech Connect

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.

McCabe, D.J.

1995-08-17

156

Solid-liquid surface free energy of Lennard-Jones liquid on smooth and rough surfaces computed by molecular dynamics using the phantom-wall method  

Microsoft Academic Search

Different model Lennard-Jones solid-liquid interfaces have been considered. In the systems, either the interaction strength between solid and liquid was varied, or the topography of the solid surface was modified. In all situations, the solid-liquid interfacial free energy variations with respect to a reference solid-liquid interface were quantified by means of a thermodynamic integration method [F. Leroy et al., Macromol.

Fre´de´ric Leroy; Florian Müller-Plathe

2010-01-01

157

Coarsening in Solid-Liquid Mixtures Studied on the Space Shuttle  

NASA Technical Reports Server (NTRS)

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 evolution of the solid particles during coarsening.

Caruso, John J.

1999-01-01

158

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

SciTech Connect

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.

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

2007-12-01

159

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

NASA Technical Reports Server (NTRS)

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.

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

1987-01-01

160

Solid-liquid mass transfer in packed beds with cocurrent gas-liquid downflow  

SciTech Connect

Local instantaneous solid-liquid mass transfer coefficients were measured in two-phase gas-liquid downflow through packed columns for 3 X 3 mm and 6 X 6 mm cylinders. An electrochemical technique was used. Liquid flow rates from 3.0 to 26.6 kg/m/sup 2/ X s and gas flow rates from 0.07 to 1.16 kg/m/sup 2/ X s covered the gas-continuous, ripple, and pulse flow regimes. Time-averaged mass transfer coefficients in trickle flow and in pulse flow for the pulse proper and the base (outside the pulse) were found to increase with increasing gas and liquid rates. Correlations are presented in terms of liquid phase Reynolds numbers and in terms of Kolmogoroff numbers. The mass transfer coefficients in the pulse were found to correspond closely to the coefficients that would be attained in the dispersed bubble flow regime.

Rao, V.G.; Drinkenburg, A.A.H.

1985-07-01

161

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

SciTech Connect

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.

Paumel, K.; Baque, F. [CEA, DEN, Nuclear Technology Department, F-13108 Saint-Paul-lez-Durance (France); Moysan, J.; Corneloup, G. [Laboratoire de Caracterisation Non Destructive, Universite de la Mediterranee, IUT Aix-en-Provence, Avenue Gaston Berger, 13625 Aix-en-Provence (France); Chatain, D. [CNRS, Aix-Marseille Universite, CINAM-UPR3118, Campus de Luminy, Case 913, 13288 Marseille cedex 09 (France)

2011-08-15

162

Solid-liquid-vapor metal-catalyzed etching of lateral and vertical nanopores  

NASA Astrophysics Data System (ADS)

Etching is an essential tool for the creation of nanostructures, where patterned metal structures can be used as masks. Here, we investigate HCl gas etching of InP substrates decorated with Au nanoparticles, and find that the etch rate is strongly increased at the Au-InP interfaces. The {111}A facets of the InP are preferentially etched. The metal nanoparticles follow in the etch direction, thereby creating nanopores. The size and position of the pores is controlled by the Au nanoparticles, and we measure nanopores as thin as 20 nm with an aspect ratio of 25:1. The direction of the nanopores is influenced by the temperature and the substrate orientation, which we use to demonstrate lateral, vertical and inclined nanopores. We explain the process by a solid-liquid-vapor model, in which the liquid metal particle catalyzes the dissolution of the solid InP.

Wallentin, Jesper; Deppert, Knut; Borgström, Magnus T.

2013-10-01

163

Dynamic analysis of piezoelectric-solid-liquid coupled system of micro nebulizer  

NASA Astrophysics Data System (ADS)

Piezoelectric micro nebulizer is a typical piezoelectric-solid-liquid coupling problem. A 2D FEM model was presented for this system. Numerical results show that when the piezoelectric actuator is vibrated, nozzle film also is generated vibration, and the phase relationship occurs to them, and the operation at the second resonance frequency is more desirable than others. A good agreement between experimental results and theoretical results confirmed the validity of the theoretical model we developed. Therefore, the design of micro nebulizer to consider only the amplitude of piezoelectric vibration is not comprehensive, we must also consider the nozzle film vibration, as well as the phase between the back film and the nozzle film, and this can provide guidance for the optimal design of micro nebulizer.

Yang, Ming-Wei; Zhou, Zhao-Ying

2008-12-01

164

Surface Specularity as an Indicator of Shock-Induced Solid-Liquid Phase Transitions  

SciTech Connect

When highly polished metal surfaces melt upon release after shock loading, they exhibit a number of features that suggest that 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 velocimetric measurements typically observed above pressures high enough to melt the free-surface. Unlike many other potential material phase-sensitive diagnostics (e.g., reflectometery, conductivity), changes in the specularity of reflection provide a dramatic, sensitive indicator of the solid-liquid phase transition. Data will be presented from multiple diagnostics that support the hypothesis that specularity changes indicate melt. These diagnostics include shadowgraphy, infrared imagery, high-magnification surface images, interferometric velocimetry, and most recently scattering angle measurements.

Gerald Stevens, Stephen Lutz, William Turley, Lynn Veeser

2007-06-29

165

Theory of acoustic scattering by supported ridges at a solid-liquid interface.  

PubMed

We combine a general Green's function formalism and an approach due to Nyborg [W. L. Nyborg, in Acoustic Streaming, Physical Acoustics, edited by W. P. Mason (Academic, London, 1965), Vol. II B, Chap. 11] to calculate the first-order pressure and second-order pressure gradient fields in the vicinity of solid inhomogeneities at a solid/liquid interface. We treat the problem of scattering of an incident acoustic plane wave by a single ridge and two parallel ridges separated by a trench on a planar substrate. The calculated vibrational density of states shows the existence of resonances at low frequencies, especially in the case of a trench. Excitation of a trench resonant vibrational mode enhances the magnitude of the first-order pressure and of the second-order pressure gradient. The resonant frequencies of a trench decrease and the pressure enhancement increases with increasing aspect ratio of the ridges (height to width). PMID:11909279

Khelif, A; Vasseur, J O; Lambin, Ph; Djafari-Rouhani, B; Deymier, P A

2002-03-01

166

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

SciTech Connect

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)

Shilova, E.; Viel, P. [CEA Saclay, DSM/IRAMIS/SPCSI, 91191Gif sur Yvette (France)] [CEA Saclay, DSM/IRAMIS/SPCSI, 91191Gif sur Yvette (France); Fournel, B.; Barre, Y. [CEA Marcoule, DTCD, BP17171, 30207 Bagnols sur Ceze (France)] [CEA Marcoule, DTCD, BP17171, 30207 Bagnols sur Ceze (France); Huc, V. [ICMMO - UMR CNRS 8182 - Bat. 420 Universite Paris-Sud (France)] [ICMMO - UMR CNRS 8182 - Bat. 420 Universite Paris-Sud (France)

2013-07-01

167

Numerical Calculation of the Morphology of a Solid/Liquid Interface near an Insoluble Particle  

NASA Technical Reports Server (NTRS)

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.

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

2003-01-01

168

Solid-Liquid Interface Motion of 4He Induced by Heat Pulse  

NASA Astrophysics Data System (ADS)

Displacement of the solid-liquid interface of 4He induced by a heat pulse of 2 ms duration was measured by a high-speed camera. Either crystallization or melting was induced at low temperatures depending on whether the heat pulse was applied to the interface from the solid side or the liquid side. The heat pulse had qualitatively the same effect on the interface as acoustic waves reported in R. Nomura et al., Phys. Rev. B 70 054516 (2004). However, the effect was smaller and a larger power was needed to induce an interface motion than acoustic waves. Another difference between them is that the heat pulse induced no interface motion at all above 0.8 K, where acoustic waves induced melting.

Saitoh, Y.; Ueda, T.; Ogasawara, F.; Abe, H.; Nomura, R.; Okuda, Y.

2006-09-01

169

Computation of solid/liquid phase change including free convection - Comparison with data  

NASA Technical Reports Server (NTRS)

A computational model is presented for solid/liquid phase-change energy transport including free convection fluid flow in the liquid phase. The computational model considers the velocity components of all nonliquid control volumes to be zero but fully solves the coupled mass-momentum problem within the liquid. The thermal energy model includes the entire domain and employs 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 problems. Grid independence is achieved, and the comparison with experimental data indicates excellent quantitative prediction of the melt fraction evolution. Qualitative data are also provided as velocity vector and isotherm plots. The computational costs incurred are quite low by comparison with other models.

Schneider, G. E.

1990-01-01

170

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

SciTech Connect

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)

McDaniel, D.; Awwad, A.; Roelant, D.; Srivastava, R. [Applied Research Center, Florida International University, Miami, FL (United States)

2008-07-01

171

Preliminary report on development of nonintrusive flow instrumentation at the ANL Solid-Liquid Test Facility  

SciTech Connect

Commercially available flowmeters, mostly of the intrusive type, have not performed well in measuring mass flow in solid/liquid media found in coal gasification plants. Argonne National Laboratory is examining or developing a number of nonintrusive flowmeters for coal gasification slurries. The performance of four nonintrusive flow instruments is assessed in a coal-oil slurry at the ANL Solid-Liquid Test Facility (SLTF). The slurry mass flow rate is determined from individual measurements of the slurry density and velocity over a range of slurry velocities from 0.4 to 3.7 m/s and coal concentrations from 0 to 60 wt %. The density and velocity are measured by the capacitive and acoustic cross-correlation flowmeters while the slurry velocity only is measured by the acoustic Doppler and gamma transmission flowmeters. For the series of flow tests, the four flowmeter systems produced quantitative information for flow regimes that ranges from Newtonian at low coal concentrations to strongly non-Newtonian at high coal concentrations. The readout of all flow instruments is compared with the independent measurements of the slurry density, velocity, and solid concentration from the SLTF 1% timed weight/volume diversion system, grab-sample evaluations, and the on-line Pulsed Neutron Activation system. The results are discussed in terms of theoretical models which verify the observed velocity dependence for each flowmetering system on the flow regime and flow sensor-specific geometry. Based on this preliminary work, improved data processing schemes and sensor geometry optimization will be sought, with the goal of developing a family of accurate nonintrusive flowmetering systems that are substantial free from readout errors over the range of flow regimes encountered in industrial coal slurry systems. 65 references, 50 figures, 10 tables.

Bobis, J.P.; Sheen, S.H.; Porges, K.G.A.; Karplus, H.B.; Farahat, M.M.; Brewer, W.E.; O'Fallon, N.M.; Raptis, A.C.

1983-12-01

172

Multiple regions of a divergent promoter control the expression of the Agrobacterium rhizogenes aux1 and aux2 plant oncogenes  

Microsoft Academic Search

The two auxin biosynthesis genes, aux1 and aux2 of Agrobacterium rhizogenes strain A4, are located on opposite DNA strands with a short integenic region (394 bp) between their coding sequences. A functional analysis of this divergent promoter is presented. The transcription initiation sites of the two aux genes were determined and regions important for promoter activity were identified by deletion

Valérie Gaudin; Christine Camilleri; Lise Jouanin

1993-01-01

173

AUX1 Promotes Lateral Root Formation by Facilitating Indole-3-Acetic Acid Distribution between Sink and Source Tissues in the Arabidopsis Seedling  

PubMed Central

Arabidopsis root architecture is regulated by shoot-derived signals such as nitrate and auxin. We report that mutations in the putative auxin influx carrier AUX1 modify root architecture as a result of the disruption in hormone transport between indole-3-acetic acid (IAA) source and sink tissues. Gas chromatography–selected reaction monitoring–mass spectrometry measurements revealed that the aux1 mutant exhibited altered IAA distribution in young leaf and root tissues, the major IAA source and sink organs, respectively, in the developing seedling. Expression studies using the auxin-inducible reporter IAA2::uidA revealed that AUX1 facilitates IAA loading into the leaf vascular transport system. AUX1 also facilitates IAA unloading in the primary root apex and developing lateral root primordium. Exogenous application of the synthetic auxin 1-naphthylacetic acid is able to rescue the aux1 lateral root phenotype, implying that root auxin levels are suboptimal for lateral root primordium initiation in the mutant.

Marchant, Alan; Bhalerao, Rishikesh; Casimiro, Ilda; Eklof, Jan; Casero, Pedro J.; Bennett, Malcolm; Sandberg, Goran

2002-01-01

174

Synthesis of cinnamyl acetate by solid–liquid phase transfer catalysis: Kinetic study with a batch reactor  

Microsoft Academic Search

The present study reports the synthesis of cinnamyl acetate (ROAc) from cinnamyl bromide (RBr) and sodium acetate (NaOAc) in a batch reactor using quaternary ammonium bromide (QBr) as a phase transfer catalyst under a solid–liquid reaction mode. The factors affecting the reaction such as kind of catalyst, agitation speed, temperature, amount of catalyst, mole ratio of cinnamyl bromide to sodium

Venu Gopal Devulapelli; Hung-Shan Weng

2009-01-01

175

Thermal transport behavior of van der Waals solids and liquids in the neighborhood of the solid-liquid phase transition  

Microsoft Academic Search

The thermal conductivity, ?, is one of the few transport coefficients which shows a relatively small change at the solid-liquid phase transition, and hence it is a property that can be used in comparing dynamic properties of both ordered and disordered systems. Although the discontinuity in ? can be accounted for largely by the difference in density, ?, of solid

J. J. Van Loef; H. J. M. Hauley; A. Cezairliyan

1986-01-01

176

Pore-Scale Acoustic Effects on Colloid Interactions at Solid\\/Liquid Interfaces under Varying Physicochemical Conditions  

Microsoft Academic Search

Acoustic energy can produce enhanced attachment and\\/or detachment of colloids at solid\\/liquid interfaces. This, in turn, can cause changes in colloid and fluid transport through porous media that depend strongly on the physical and chemical properties of the porous matrix, the fluid contained in the matrix pore space, and the colloids suspended in the fluid. Accumulation or release of colloids

P. M. Roberts

2005-01-01

177

Correlation between numerical field computation and experimental investigations on the parameters governing the flashover behavior of solid\\/liquid interfaces  

Microsoft Academic Search

This paper compares experimental investigations dealing with the ac breakdown and flashover strength of liquid insulated gaps without and with a parallel solid\\/liquid interface in a non-uniform electrical field with results obtained from field calculations obtained using the finite element method. The liquids investigated were a mineral based transformer oil and an ester liquid, the solid insulating materials were laminated

M. Krins; J. Gartner; R. Jochem; E. Gockenbach

2000-01-01

178

Temperature-reversible ultrathin films of N-isopropylacrylamide terpolymer adsorbed at the solid-liquid interface.  

PubMed

This article describes the stability and reversibility of ultrathin films of N-isopropylacrylamide (NIPA)-vinylimidazole (VI)-poly(ethylene glycol) (PEG) graft terpolymer adsorbed at the solid-liquid interface upon temperature cycling from below to above its phase transition temperature. The coil-to-globule and globule-to-coil phase transitions were captured by in situ fluid tapping atomic force microscopy (AFM). The film thickness of 1 nm was determined by AFM, X-ray photoelectron spectroscopy, and X-ray reflectivity. The concentration required to reach full coverage was found to be higher when adsorption occurred below the phase transition temperature. From 23 to 42 degrees C, the adsorbed NIPA terpolymer film was observed to be molecularly smooth, corresponding to the close-packed structure of flexible polymer coils. Particles containing between one and a few globules appeared abruptly at the interface at 42-43 degrees C, the same temperature as the solution phase transition temperature, which was determined by dynamic light scattering. The size of the particles did not change with temperature, whereas the number of particles increased with increasing temperature up to 60 degrees C. The particles correspond to the collapsed and associated state of the globules. The film morphological changes were found to be reversible upon temperature cycling. Subtle differences were observed between dip-coated and spin-coated films that are consistent with a higher degree of molecular freedom for spin-coated films. The study contributes to the fundamental understanding and applications of smart ultrathin films and coatings. PMID:17963410

Wan, Lei; Bisht, Harender S; You, Ye-Zi; Oupicky, David; Mao, Guangzhao

2007-11-20

179

Chemical, structural and electronic characterization of solid-liquid aluminum-silicon alloys using in-situ TEM  

NASA Astrophysics Data System (ADS)

Studying solid-liquid interfaces in multi-component alloys is important for understanding the thermodynamic and kinetic behaviors of phases during solidification and melting. Previous investigations pertaining to characterization of solid-liquid interfaces have been limited due to restricted experimental accessibility. In this study, solid-liquid interfaces in atomized powders of hypereutectic Al-Si based alloy were investigated using in-situ transmission electron microscopy (TEM). A thermal shield developed during 'the study allowed chemical characterization of solid-liquid interfaces and phases to be performed as a function of temperature, thereby directly determining solute partitioning and the metastable phase boundary of the undercooled liquid. In addition, kinetic analyses involving the nucleation, growth and dissolution behaviors of primary Si and the Al solid-solution were also performed. The morphological evolutionary paths of primary Si and the Al solid-solution were found to be fundamentally different due to the underlying interfacial energetics. Moreover, electron energy-loss spectroscopy (EELS) was used to study the variation in plasmon energy as a function of temperature in liquid and solid phases and across the solid-liquid interface. The plasmon energy-temperature trend in the liquid alloy was found to be markedly different from the case of pure liquid Al, revealing the electronic effects of alloying additions to the liquid phase. The energy-loss near edge structures (ELNES) of the liquid alloy also showed remarkably different electronic structure of the unoccupied density of states (DOS) in comparison to pure liquid Al, indicating a fundamental electronic structure variation in the liquid due to solute additions.

Eswaramoorthy, Santhana K.

180

Air sparging during the solid\\/liquid separation by microfiltration: application of flotation  

Microsoft Academic Search

A large number of techniques have been used today to limit the membranes fouling and among them, certainly is air bubbling constituting also the transport medium in flotation, as applied in wastewater treatment; flotation is suitable as a pretreatment stage for microfiltration. Ceramic flat-sheet membrane modules were used in this paper, of multi-channel geometry and mainly their fouling tendency and

K. A. Matis; E. N. Peleka; D. Zamboulis; T. Erwe; V. Mavrov

2004-01-01

181

Neutron reflectivity at the solid\\/liquid interface: examples of applications in biophysics  

Microsoft Academic Search

Over the last 20 years, neutron reflection has emerged as a powerful technique for investigating inhomogeneities across an interface, inhomogeneities either in composition (Lu and Thomas 1998 J. Chem. Soc. Faraday Trans.94 995) or magnetization (Felcher 1981 Phys. Rev. B 24 1995). By measuring the reflected over the incoming intensity of a well collimated beam striking at an interface, as

Giovanna Fragneto-Cusani

2001-01-01

182

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

PubMed Central

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.

dos Santos, Silvia Cristina Cunha; Ouellette, Julianne; Juteau, Pierre; Lepine, Francois; Deziel, Eric

2013-01-01

183

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

SciTech Connect

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.

Zwol, P. J. van; Palasantzas, G.; De Hosson, J. Th. M. [Department of Applied Physics, Materials Innovation Institute M2i and Zernike Institute for Advanced Materials, University of Groningen, 9747 AG Groningen (Netherlands)

2009-05-15

184

Acoustic Monitor for Solid-Liquid Slurries Measurements at Low Weight Fractions  

SciTech Connect

We have developed an acoustic monitor for accurate, real-time measurement of solids concentration in solid-liquid (S-L) and solid-gas-liquid (S-G-L) slurries at low solids weight percent (0.5 to 10 wt. %). The Syracuse Acoustic Monitor (SAM) has potential for slurry transport monitoring, processing stream monitoring, and process control capabilities for nuclear wastes treatment throughout the DOE complex. The SAM is based on theory that predicts attenuation of small-amplitude acoustic waves propagating through S-L and S-L-G suspensions. We developed a prototype in-line system with robust data acquisition capabilities to continually acquire attenuation data (response time of 0.5 sec) for a 0.6-12 MHz frequency range with an array of transducers. Test results on an integrated flow loop indicate high accuracy between 0.5 and 8.0 weight percent solids for ceramic microspheres (80 {micro}m average diameter) and kaolin-bentonite slurries. Results of removal of the interference caused by gas bubbles, thus providing the solids weight percent, will also be discussed.

Tavlarides, Lawrence L.; Shcherbakov, Oleksandr; Dievendorf, Eric; Sangini, Ashok

2003-09-10

185

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

SciTech Connect

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.

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

2003-06-01

186

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

NASA Technical Reports Server (NTRS)

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.

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

2013-01-01

187

Fluctuations and Criticality of a Granular Solid-Liquid-Like Phase Transition  

NASA Astrophysics Data System (ADS)

We present an experimental study of density and order fluctuations in the vicinity of the solid-liquid-like transition that occurs in a vibrated quasi-two-dimensional granular system. The two-dimensional projected static and dynamic correlation functions are studied. We show that density fluctuations, characterized through the structure factor, increase in size and intensity as the transition is approached, but they do not change significantly at the transition itself. The dense, metastable clusters, which present square symmetry, also increase their local order in the vicinity of the transition. This is characterized through the bond-orientational order parameter Q4, which in Fourier space shows an Ornstein-Zernike-like behavior. Depending on the filling density and vertical height, the transition can be of first- or second-order type. In the latter case, the associated correlation length ?4, the relaxation time ?4, the zero k limit of Q4 fluctuations (static susceptibility), the pair correlation function of Q4, and the amplitude of the order parameter obey critical power laws, with saturations due to finite size effects. Their respective critical exponents are ??=1, ??=2, ?=1, ?=0.67, and ?=1/2, whereas the dynamical critical exponent z=??/??=2. These results are consistent with model C of dynamical critical phenomena, valid for a nonconserved critical order parameter (bond-orientation order) coupled to a conserved field (density).

Castillo, Gustavo; Mujica, Nicolás; Soto, Rodrigo

2012-08-01

188

Hydrogen adsorption energies on bimetallic overlayer systems at the solid vacuum and the solid liquid interface  

NASA Astrophysics Data System (ADS)

Atomic hydrogen adsorption energies on bimetallic overlayer systems have been determined by periodic density functional theory calculations within the generalized gradient approximation. On the pseudomorphic Pd/Cu(1 1 1) surface, both the substrate interaction and the lattice compression of the Pd overlayer lead to smaller hydrogen binding energies. For pseudomorphic Cu/Pd(1 1 1), on the other hand, the strong Cu-Pd interaction results in larger binding energies. Hence, both Pd/Cu(1 1 1) and Cu/Pd(1 1 1) exhibit an intermediate behavior between pure Cu(1 1 1) and pure Pd(1 1 1). In addition, we have determined the atomic hydrogen adsorption on Pd/Au(1 1 1) in the presence of a water overlayer. The hydrogen adsorption energies are changed by less than 60 meV by the most stable H 2O bilayer compared to the clean surface. This indicates that theoretical adsorption studies at the solid-vacuum interface might also be relevant for the solid-liquid interface.

Roudgar, Ata; Groß, Axel

2005-12-01

189

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

SciTech Connect

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, .

Wang, J. [University of Nebraska, Lincoln; Apte, Pankaj [Indian Institute of Technology, Kanpur; Morris, James R [ORNL; Zeng, X.C. [University of Nebraska, Lincoln

2013-01-01

190

Solid-liquid separation of oxidized americium from fission product lanthanides  

NASA Astrophysics Data System (ADS)

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.

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

2010-03-01

191

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

NASA Technical Reports Server (NTRS)

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

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

2004-01-01

192

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

PubMed

We have studied the low temperature phase diagram and water activities of the ammonium sulfate/glutaric acid/water system using differential scanning calorimetry, infrared spectroscopy of thin films, and a new technique: differential scanning calorimetry-video microscopy. Using these techniques, we have determined that there is a temperature-dependent kinetic effect to the dissolution of glutaric acid in aqueous solution. We have mapped the solid/liquid ternary phase diagram, determined the water activities based on the freezing point depression, and determined the ice/glutaric acid phase boundary as well as the ternary eutectic composition and temperature. We have also modified our glutaric acid/water binary phase diagram previously published based on these new results. We compare our results for the ternary system to the predictions of the Extended AIM Aerosol Thermodynamics Model (E-AIM), and find good agreement for the ice melting points in the ice primary phase field of this system; however, significant differences were found with respect to phase boundaries, concentration and temperature of the ternary eutectic, and glutaric acid dissolution. PMID:23544733

Beyer, Keith D; Pearson, Christian S; Henningfield, Drew S

2013-05-01

193

L'Anse Aux Meadows, Newfoundland  

NASA Technical Reports Server (NTRS)

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.

2008-01-01

194

Solid-Liquid Equilibria for the CO2 + R143a and N2O + R143a Systems  

NASA Astrophysics Data System (ADS)

A recently built experimental setup for determination of solid-liquid equilibria was slightly modified. The action taken on the existing system focused on correcting the drawbacks of the cooling system. In this version of the setup, a direct liquid nitrogen supply was preferred. By means of the modified apparatus, solid-liquid equilibria of the CO2 + R143a and N2O + R143a binary systems were studied. The triple point of R143a was measured to check the reliability of the modified apparatus, revealing good consistency with the literature. The system’s behavior was measured down to temperatures of 148 K. The results obtained for the mixtures were interpreted by means of the Schröder equation.

di Nicola, Giovanni; Moglie, Matteo; Santori, Giulio; Stryjek, Roman

2009-07-01

195

CFD SIMULATION OF SOLID-LIQUID TWO-PHASE FLOW IN BAFFLED STIRRED VESSELS WITH RUSHTON IMPELLERS  

Microsoft Academic Search

Three-dimensional flow field and solid concentration distribution in solid-liquid baffled stirred vessels are numerically simulated using an improved inner-outer iterative procedure. A two-fluid approach and the single phase ? ? k turbulence model are employed. The recirculation loop below the impeller and above the bottom is predicted. Agreement of simulation results with experimental data is satisfactory for both mean velocities

Feng WANG; Weijing WANG; Yuefa WANG; Zai-Sha MAO

196

Detecting filter-cake pathologies in solid–liquid filtration: semi-tech scale demonstrations using electrical resistance tomography (ERT)  

Microsoft Academic Search

Solid–liquid filtration monitoring by means of a single inexpensive 16-element ring sensor array for electrical resistance tomography (ERT) is described. The high sensitivity of the UMIST Mark 1b-E data acquisition system led to the unexpected finding that this tomography array can detect movement of the liquid level during filtration. This degree of sensitivity was also capable of detecting any tilt

D. Vlaev; M. Wang; T. Dyakowski; R. Mann; B. D. Grieve

2000-01-01

197

Heat transfer characteristics of a rectangular natural circulation loop containing solid-liquid phase-change material suspensions  

Microsoft Academic Search

Purpose – To examine the heat transfer characteristics of soild-liquid phase change material (PCM) suspensions in a rectangular natural circulation loop. Design\\/methodology\\/approach – A continuum mixture flow model is used for the buoyancy-driven circulation flow of the PCM suspensions together with an approximate enthalpy model to describe the solid-liquid phase change (melting\\/freezing) process of the PC particles in the loop.

C. J. Ho; S. Y. Chiu; J. F. Lin

2005-01-01

198

Binary solid–liquid–gas equilibrium of the tripalmitin\\/CO 2 and ubiquinone\\/CO 2 systems  

Microsoft Academic Search

A conventional method was used to measure the melting points of the natural lipid tripalmitin and of the coenzyme ubiquinone (coQ10) under high pressure carbon dioxide. The pressure–temperature behavior of the binary three-phase solid–liquid–gas (SLG) equilibrium for these and other systems, namely naphthalene and biphenyl with carbon dioxide, ethylene and ethane, were investigated using the Peng–Robinson equation of state (PR-EoS)

Jun Li; Miguel Rodrigues; Alexandre Paiva; Henrique A. Matos; Edmundo Gomes de Azevedo

2006-01-01

199

A novel solid–liquid two-phase partitioning bioreactor for the enhanced bioproduction of 3-methylcatechol  

Microsoft Academic Search

The bioproduction of 3-methylcatechol from toluene via Pseudomonas putida MC2 was performed in a solid-liquid two-phase partitioning bioreactor with the intent of increasing yield and productivity over a single-phase system. The solid phase consisted of HYTRELTM, a thermo- plastic polymer that was shown to possess superior affinity for the inhibitory 3-methylcatechol compared to other candidate polymers as well as a

George P. Prpich; Andrew J. Daugulis

2007-01-01

200

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

Microsoft Academic Search

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.

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

2003-01-01

201

A Godunov-type finite-volume scheme for unified solid-liquid elastodynamics on arbitrary two-dimensional grids  

Microsoft Academic Search

A Godunov-type finite-volume scheme is presented for the elastodynamic equations written in terms of displacement velocities and stresses. The mathematical model universally includes elastic solids and liquids resulting in a method highly suitable for studies of acoustic wave scattering at solid-liquid interfaces. The scheme is written for a generic grid of control volumes in two spatial dimensions. The governing equations

P. Voinovich; A. Merlen; E. Timofeev; K. Takayama

2003-01-01

202

Development of a model for thin-film stability and spreading in solid–liquid–liquid systems  

Microsoft Academic Search

The presence of thin aqueous films and their stability has a profound effect on reservoir rock–fluids interactions involved in spreading and adhesion. The stability of thin wetting aqueous films on rock surfaces is governed by several variables including pH, brine and crude oil compositions, and capillary pressure. These variables govern the wetting states in the solid–liquid–liquid systems. The wetting states

Chandrasekhar Busireddy; Dandina N. Rao

2007-01-01

203

A dynamic model for the interaction between a solid particle and an advancing solid\\/liquid interface  

Microsoft Academic Search

Most models that describe the interaction of an insoluble particle with an advancing solid-liquid interface are based on the\\u000a assumption of steady state. However, as demonstrated by experimental work, the process does not reach steady state until the\\u000a particle is pushed for a while by the interface. In this work, a dynamic mathematical model was developed. The dynamic model\\u000a demonstrates

Adrian V. Catalina; Sundeep Mukherjee; DORU M. STEFANESCU

2000-01-01

204

Molecular interactions at the solid liquid interface with special reference to flotation and solid particle stabilized emulsions  

Microsoft Academic Search

Summary The experiments carried out with a variety of pure surface active agents, employed in flotation of ores as either collectors or frothers, show that (a) long chain homologues of alcohols and alkyl sulphates react strongly with xanthates at the air\\/liquid interface (Langmuir-trough experiments), (b) the molecular interactions between frothers and collectors occur at the solid\\/liquid interface — if the

J. H. Schulman; J. Leja

1954-01-01

205

Effects of the thermocapillary convection on the flow stability and on the solid\\/liquid interface horizontal bridgman growth  

Microsoft Academic Search

This work concerns the study of the convective instabilities interacting with the solid\\/liquid interface for a horizontal Bridgman configuration filled with a low Prandtl number material (Pr=0.015). This kind of configuration was the subject of several studies restricted to fluid phase. It was well established the existence of convective oscillatory regime in a tall horizontal cavity. The coupling of such

M. El Ganaoui; E. Senna; R. Bennacer; P. Bontoux

2004-01-01

206

In-situ observation of solid-liquid interface during directional solidification of succinonitrile and pivalic acid  

Microsoft Academic Search

The aim of this work is the direct study of the solid-liquid interface development in bulk 3D samples under directional solidification\\u000a in different crystallographic orientations in ground and microgravity conditions. Flight experimental installation “MORPHOS”\\u000a intended for directional solidification of transparent substances is under development. Ground-based experiments in 3D and\\u000a quasi 2D samples are in progress.

A. P. Shpak; O. P. Fedorov; E. L. Zhivolub; Y. J. Bersudskyy; O. V. Shuleshova

2005-01-01

207

Simultaneous biodegradation of volatile and toxic contaminant mixtures by solid-liquid two-phase partitioning bioreactors.  

PubMed

Microbial inhibition and stripping of volatile compounds are two common problems encountered in the biotreatment of contaminated wastewaters. Both can be addressed by the addition of a hydrophobic auxiliary phase that can absorb and subsequently re-release the substrates, lowering their initial aqueous concentrations. Such systems have been described as Two Phase Partitioning Bioreactors (TPPBs). In the current work the performances of a solid-liquid TPPB, a liquid-liquid TPPB and a single phase reactor for the simultaneous degradation of butyl acetate (the volatile component) and phenol (the toxic component) have been compared. The auxiliary phase used in the solid-liquid TPPB was a 50:50 polymer mixture of styrene-butadiene rubber and Hytrel 8206, with high affinities for butyl acetate and phenol, respectively. The liquid-liquid TPPB employed silicone oil which has fixed physical properties, and had no capacity to absorb the toxic contaminant (phenol). Butyl acetate degradation was enhanced in both TPPBs relative to the single phase, arising from its sequestration into the auxiliary phase, thereby reducing volatilization losses. The solid-liquid TPPB additionally showed a substantial increase in the phenol degradation rate, relative to the silicone oil system, demonstrating the superiority and versatility of polymer based systems. PMID:23611802

Poleo, Eduardo E; Daugulis, Andrew J

2013-06-15

208

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

PubMed

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

Li, Qinghao; Wei, Lin; Xie, Yanru; Zhang, Kai; Liu, Lei; Zhu, Dapeng; Jiao, Jun; Chen, Yanxue; Yan, Shishen; Liu, Guolei; Mei, Liangmo

2013-01-01

209

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

PubMed

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)] 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. PMID:22938254

Nair, Anjan R; Sathian, Sarith P

2012-08-28

210

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

SciTech Connect

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.

Kabadi, V.N.; Ilias, S.

1995-10-01

211

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

NASA Astrophysics Data System (ADS)

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.

Li, Qinghao; Wei, Lin; Xie, Yanru; Zhang, Kai; Liu, Lei; Zhu, Dapeng; Jiao, Jun; Chen, Yanxue; Yan, Shishen; Liu, Guolei; Mei, Liangmo

2013-10-01

212

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

NASA Technical Reports Server (NTRS)

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 systems included metal-ceramic particles (pure aluminum - zirconia particles) and transparent organic - non-reactive particles (succinonitrile - polystyrene and biphenyl - glass). This paper will discuss the experimental results obtained in both lg and pg conditions and the influence of the natural convection on V(sub cr). A summary of past mathematical models and our recent theoretical developments will also be presented to explain the experimentally observed particle/SLI interaction.

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

2003-01-01

213

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

PubMed

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

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

2011-01-01

214

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

NASA Astrophysics Data System (ADS)

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.

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

2004-05-01

215

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

SciTech Connect

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.

Stabnikova, O. [School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore)], E-mail: costab@ntu.edu.sg; Liu, X.Y.; Wang, J.Y. [School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore)

2008-07-01

216

Preparation of the initial solid liquid interface and melt in directional solidification  

NASA Astrophysics Data System (ADS)

The preparation of the initial conditions (solid-liquid interface morphology and solute segregation in the liquid phase) on which growth is started is a very critical step in directional-solidification experiments. Dedicated experiments on Al-1.5 wt% Ni consisting in directional melting followed by thermal stabilisation with different lengths, show that precise control is in practice not straightforward. Indeed, in the mushy zone created by melting the original solid sample, temperature gradient zone melting (TGZM) causes migration of solute-rich liquid droplets and channels. A model is proposed to describe this process and validate the physical interpretation of the experiments through numerical simulation. Knowing the status of the preparation, the intriguing observations in the partially melted region of the Al-1.5 wt% Ni alloys solidified in the Advanced Gradient Heating Facility of European Space Agency during the LMS and STS-95 space missions can now be explained. Finally, the influence of initial interface morphology and melt segregation on directional-solidification transient is discussed, based on a comparison of Al-Ni alloys with hypoeutectic Al-Li alloys previously grown on Earth and in space. It follows that for experiments achieved on original rods with equiaxed microstructure, the efficiency of the preparatory melting and stabilisation phases can be evaluated from the solute macrosegregation profile in the region in between the non-melted solid and directional solidification. The major conclusion is that when the melt is mixed by fluid flow, the initial conditions are near to their asymptotic state at the end of TGZM whereas, when solute diffusion is the mode of transport into the bulk liquid, the condition of homogeneous melt becomes limiting and too much time-consuming to be fulfilled, which in particular holds for the 3D-experiments carried out in the reduced-gravity environment of space.

Nguyen Thi, H.; Drevet, B.; Debierre, J. M.; Camel, D.; Dabo, Y.; Billia, B.

2003-06-01

217

Real Time Characterization of Solid/Liquid Interfaces During Directional Solidification  

NASA Technical Reports Server (NTRS)

A X-Ray Transmission Microscope (XTM) has been developed to observe in real time and in-situ solidification phenomenon at the solid/liquid interface. Recent improvements in the horizontal Bridgman furnace design provides real-time magnification (during solidification) up to 12OX. The increased magnification has enabled for the first time the XTM imaging of real-time growth of fibers and particles with diameters of 3-6 micrometers. Further, morphological transitions from planar to cellular interfaces have also been imaged. Results from recent XTM studies on Al-Bi monotectic system, Al-Au eutectic system and interaction of insoluble particles with s/I interfaces in composite materials will be presented. An important parameter during directional solidification of molten metal is the interfacial undercooling. This parameter controls the morphology and composition at the s/I interface. Conventional probes such as thermocouples, due to their large bead size, do not have sufficient resolution for measuring undercooling at the s/I interface. Further, the intrusive nature of the thermocouples also distorts the thermal field at the s/I interface. To overcome these inherent problems we have recently developed a compact furnace which utilizes a non-intrusive technique (Seebeck) to measure undercooling at the S/I interface. Recent interfacial undercooling measurements obtained for the Pb-Sn system will be presented. The Seebeck measurement furnace in the future will be integrated with the XTM to provide the most comprehensive tool for real time characterization of s/I interfaces during solidification.

Sen, S.; Kaukler, W. K.; Curreri, P. A.; Peters, P.

1997-01-01

218

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

SciTech Connect

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 will be used to suggest a design for integration into commercial-scale production.

Rogers, S.; Cook, J.; Juratovac, J.; Goodwillie, J.; Burke, T.; Stuart, B., ed.

2011-10-25

219

SOLID-LIQUID MASS TRANSFER AND WETTING FACTORS IN TRICKLE BED REACTORS: EFFECT OF THE TYPE OF SOLID PHASE AND THE PRESENCE OF CHEMICAL REACTION  

Microsoft Academic Search

The solid-liquid wetting factor, f, for solid dissolution in a liquid with and without chemical reaction was experimentally determined in a fixed bed three-phase reactor with downward concurrent gas and liquid flows (Trickle Bed Reactor). The method employed consisted of comparing the volumetric solid-liquid mass transfer coefficient obtained when two phases (liquid and gas) circulated through the bed, with those

DOSINDA GONZÁLEZ-MENDIZABAL; MARÍA EUGENIA AGUILERA; FILIPPO PIRONTI

1998-01-01

220

A numerical analysis of solid-liquid phase change heat transfer around a single and two horizontal, vertically spaced cylinders in a rectangular cavity  

Microsoft Academic Search

In the present study, a new numerical model is proposed to analyze solid-liquid phase change heat transfer in a complicated geometry. The present model can treat the solid\\/liquid phase change heat transfer with\\/without porous media, as well as conventional transient natural convection with\\/without porous media. Solidification calculations of pure water (without porous media) around a single cylinder and two cylinders

R. Viskanta

1997-01-01

221

Maladies reli?es aux loisirs aquatiques  

PubMed Central

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.

Sanborn, Margaret; Takaro, Tim

2013-01-01

222

Phase diagrams and kinetics of solid-liquid phase transitions in crystalline polymer blends  

NASA Astrophysics Data System (ADS)

A free energy functional has been formulated based on an order parameter approach to describe the competition between liquid-liquid phase separation and solid-liquid phase separation. In the free energy description, the assumption of complete solvent rejection from the crystalline phase that is inherent in the Flory diluent theory was removed as solvent has been found to reside in the crystalline phase in the form of intercalates. Using this approach, we have calculated various phase diagrams in binary blends of crystalline and amorphous polymers that show upper or lower critical solution temperature. Also, the discrepancy in the chi values obtained from different experimental methods reported in the literature for the polymer blend of poly(vinylidenefluoride) and poly(methylmethacrylate) has been discussed in the context of the present model. Experimental phase diagram for the polymer blend of poly(caprolactone) and polystyrene has also been calculated. Of particular importance is that the crystalline phase concentration as a function of temperature has been calculated using free energy minimization methods instead of assuming it to be pure. In the limit of complete immiscibility of the solvent in the crystalline phase, the Flory diluent theory is recovered. The model is extended to binary crystalline blends and the formation of eutectic, peritectic and azeotrope phase diagrams has been explained on the basis of departure from ideal solid solution behavior. Experimental eutectic phase diagram from literature of a binary blend of crystalline polymer poly(caprolactone) and trioxane were recalculated using the aforementioned approach. Furthermore, simulations on the spatio temporal dynamics of crystallization in blends of crystalline and amorphous polymers were carried out using the Ginzburg-Landau approach. These simulations have provided insight into the distribution of the amorphous polymer in the blends during the crystallization process. The simulated results are in close accordance with the experimentally observed concentration profiles of atactic polypropylene during the crystallization of isotactic polypropylene in a blend of these polymers. Finally described are the unique thermodynamics and kinetics that occur in thermoplastic elastomer blends of polypropylene and synthetic rubber, leading to the unique biphasic crystalline morphology imparting these blends with their characteristic high toughness and high impact strength. Phase diagrams in such blends exhibit a combined upper and lower critical solution temperature. These phase diagrams have been calculated based on the present model developed, and simulated results explain the structural development in these blends.

Matkar, Rushikesh A.

223

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

NASA Technical Reports Server (NTRS)

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.

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

2013-01-01

224

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

NASA Astrophysics Data System (ADS)

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.

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

2011-03-01

225

Real time, high resolution studies of protein adsorption and structure at the solid liquid interface using dual polarization interferometry  

NASA Astrophysics Data System (ADS)

A novel method for the analysis of thin biological films, called dual polarization interferometry (DPI), is described. This high resolution (<1 Å), laboratory-based technique allows the thickness and refractive index (density) of biological molecules adsorbing or reacting at the solid-liquid interface to be measured in real time (up to 10 measurements per second). Results from the adsorption of bovine serum albumin (BSA) on to a silicon oxynitride chip surface are presented to demonstrate how time dependent molecular behaviour can be examined using DPI. Mechanistic and structural information relating to the adsorption process is obtained as a function of the solution pH.

Freeman, Neville J.; Peel, Louise L.; Swann, Marcus J.; Cross, Graham H.; Reeves, Andrew; Brand, Stuart; Lu, Jian R.

2004-07-01

226

A computational model for the analysis of diffusive binary alloy solid/liquid phase change energy transport  

NASA Technical Reports Server (NTRS)

A model is presented for the prediction of solid/liquid, binary alloy, phase change energy transport. The model incorporates only one-dimensional, diffusive transport of both energy and species but is not inherently limited in any way to such a restriction. The model incorporates a previously developed algorithm for single constituent phase change energy transport and is applied to the energy transport as well as the species transport aspects of the problem. The model is applied to four example cooling problems and is shown to perform exceedingly well from an algorithmic point of view.

Schneider, G. E.

1991-01-01

227

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

NASA Technical Reports Server (NTRS)

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.

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

1999-01-01

228

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

NASA Technical Reports Server (NTRS)

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.

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

1999-01-01

229

In-situ hot pressing\\/solid-liquid reaction synthesis of dense titanium silicon carbide bulk ceramics  

Microsoft Academic Search

An in-situ hot pressing\\/solid-liquid reaction process was developed for the synthesis of dense polycrystalline Ti3SiC2 ceramics using Ti, Si, and graphite powders as starting materials. The present work demonstrated that this process was one\\u000a of the most effective and simple methods for the preparation of dense bulk Ti3SiC2 materials. Lattice constants of a=3.068 and c=17.645 are calculated for Ti3SiC2 made

Y. Zhou; Zhimei Sun; Shengqi Chen; Y. Zhang

1998-01-01

230

Fluoroponytailed crown ethers and quaternary ammonium salts as solid-liquid phase transfer catalysts in organic synthesis.  

PubMed

Fluorous derivatives of dibenzo-18-crown-6 ether were prepared, and then successfully applied in representative solid-liquid phase transfer catalysis reactions, which were performed in standard organic solvents, such as chlorobenzene and toluene, as well as in fluorous solvents, such as perfluoro-1,3-dimethylcyclohexane. It was clearly shown that properly designed fluoroponytailed crown ethers could promote the disintegration of the crystal lattice of alkali salts, and transfer anions from the solid surface into an apolar, non-coordinating perfluorocarbon phase, for phase transfer catalysis reactions in organic synthesis. Furthermore, 3,5-bis(perfluorooctyl)benzyl bromide and triethylamine were reacted under mild conditions to provide an analogue of the versatile phase transfer catalyst, benzyltriethylammonium chloride, containing two fluoroponytails. This fluoroponytailed quaternary ammonium salt was also successfully employed as a catalyst in a variety of organic reactions conducted under solid-liquid phase transfer catalysis conditions, without a perfluorocarbon phase. Thus, being both hydrophobic and lipophobic, fluorous crown ethers and ammonium salts, could be rapidly recovered in quantitative yields, and reused without loss of activity, over several reaction cycles. PMID:21928010

Pozzi, Gianluca; Fish, Richard H

2012-01-01

231

Probing charge screening dynamics and electrochemical processes at the solid-liquid interface with electrochemical force microscopy.  

PubMed

The presence of mobile ions complicates the implementation of voltage-modulated scanning probe microscopy techniques such as Kelvin probe force microscopy (KPFM). Overcoming this technical hurdle, however, provides a unique opportunity to probe ion dynamics and electrochemical processes in liquid environments and the possibility to unravel the underlying mechanisms behind important processes at the solid-liquid interface, including adsorption, electron transfer and electrocatalysis. Here we describe the development and implementation of electrochemical force microscopy (EcFM) to probe local bias- and time-resolved ion dynamics and electrochemical processes at the solid-liquid interface. Using EcFM, we demonstrate contact potential difference measurements, consistent with the principles of open-loop KPFM operation. We also demonstrate that EcFM can be used to investigate charge screening mechanisms and electrochemical reactions in the probe-sample junction. We further establish EcFM as a force-based imaging mode, allowing visualization of the spatial variability of sample-dependent local electrochemical properties. PMID:24846328

Collins, Liam; Jesse, Stephen; Kilpatrick, Jason I; Tselev, Alexander; Varenyk, Oleksandr; Okatan, M Baris; Weber, Stefan A L; Kumar, Amit; Balke, Nina; Kalinin, Sergei V; Rodriguez, Brian J

2014-01-01

232

Molecular dynamics study of melting curve, entropy of fusion and solid–liquid interfacial energy of cobalt under pressure  

NASA Astrophysics Data System (ADS)

We performed molecular dynamics (MD) simulations with the two embedded atom method (EAM) potentials to calculate the melting curves of cobalt over a wide range of pressure. Zhou?s EAM potential can produce satisfying results, in better agreement with the experiment compared with Pun?s. Based on Zhou?s potential, we simulated the melting of Co with two approaches, i.e., the one-phase (hysteresis) method and two-phase (solid–liquid coexistence) method. Both approaches can effectively reduce the superheating, and their results are in the close proximity at the applied pressures. With the one-phase method, during the investigation of the entropy of fusion of Co, we found that with the pressure increasing, the entropy of fusion decreases rapidly first and then oscillates with pressure; when the pressure is beyond 100 GPa, the entropy of fusion shows less pressure effect. When taking account of the solid–liquid interfacial energy at different pressures, we found that it increases monotonically with pressure, and can be well described as a fifth-order polynomial relation. Moreover, the thermal equation of state (EOS) and the temperature dependence of atomic structures of Co have been obtained successfully.

Zhang, Wen-jin; Peng, Yu-feng; Liu, Zhong-li

2014-05-01

233

Rapid carbonation for calcite from a solid-liquid-gas system with an imidazolium-based ionic liquid.  

PubMed

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

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

2014-01-01

234

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

SciTech Connect

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.

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

235

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

NASA Astrophysics Data System (ADS)

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.

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

2013-06-01

236

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

NASA Astrophysics Data System (ADS)

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.

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

237

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

NASA Astrophysics Data System (ADS)

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.

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

2006-05-01

238

X-ray reflectivity measurements of layer-by-layer films at the solid/liquid interface.  

PubMed

In this Letter, we present a method for the decoration of layer-by-layer (LbL) structures by heavy metal ions, which allows X-ray reflectivity (XRR) measurements at the solid/water interface. The improved contrast has allowed us to obtain well-structured X-ray reflectivity curves from samples at the liquid/solid interface that can be used for the film structure modeling. The developed technique was also used to follow the formation of complexes between DNA and the LbL multilayer. The XRR data are confirmed by independent null-ellipsometric measurements at the solid/liquid interface on the very same architectures. PMID:18823138

Erokhina, Svetlana; Berzina, Tatiana; Cristofolini, Luigi; Erokhin, Victor; Folli, Claudia; Konovalov, Oleg; Marino, Iari-Gabriel; Fontana, M P

2008-11-01

239

Study of (Solid-Liquid) Phase Equilibria for Mixtures of Energetic Material Stabilizers and Prediction for Their Subsequent Performance  

NASA Astrophysics Data System (ADS)

Solid-liquid equilibria for three binary mixtures of 2-nitrodiphenylamine (1) + diphenylamine (2), ethyl centralite (1) + N-ethyl-4-nitro- N-nitrosoaniline (2), and 2,2^' }-dinitrodiphenylamine (1) + N-ethyl-4-nitro- N-nitrosoaniline (2) were measured using a differential scanning calorimeter. Simple eutectic behaviors for these systems were observed. The experimental results were correlated by means of original and modified NRTL, Wilson, and UNIQUAC equations. The root-mean-square deviations of the solubility temperatures for all measured data vary from 0.63 K to 3.73 K and depend on the particular model used. The best solubility correlation was obtained with the UNIQUAC model.

Trache, Djalal; Khimeche, Kamel; Dahmani, Abdallah

2013-02-01

240

Grazing-incidence neutron-induced fluorescence probes density profiles of labeled molecules at solid/liquid interfaces.  

PubMed

We report on the use of characteristic prompt ?-fluorescence after neutron capture induced by an evanescent neutron wave to probe densities and depth profiles of labeled molecules at solid/liquid interfaces. In contrast to classical scattering techniques and X-ray fluorescence, this method of "grazing-incidence neutron-induced fluorescence" combines direct chemical specificity, provided by the label, with sensitivity to the interface, inherent to the evanescent wave. We demonstrate that the formation of a supported lipid membrane can be quantitatively monitored from the characteristic fluorescence of (157)Gd(3+) ions bound to the headgroup of chelator lipids. Moreover, we were able to localize the (157)Gd(3+) ions along the surface normal with nanometer precision. This first proof of principle with a well-defined model system suggests that the method has a great potential for biology and soft matter studies where spatial resolution and chemical sensitivity are required. PMID:23461763

Schneck, Emanuel; Jentschel, Michael; Gege, Christian; Tanaka, Motomu; Demé, Bruno

2013-03-26

241

Use of complementary neutron techniques in studying the effect of a solid/liquid interface on bulk solution structures  

SciTech Connect

By appropriate combination of neutron scattering techniques, it is possible to obtain structural information at various distances from a solid/liquid interface and thus probe in some detail how the surface structures evolve into bulk structures. We have used neutron reflectometry (NR) with a newly developed shear cell, near surface small angle neutron scattering (NSSANS) again in combination with the new shear cell, and regular small angle neutron scattering (SANS) with a standard Couette shear cell to probe the structures formed in our aqueous surfactant systems and how they react to a flow field, particularly in the near surface region of a solid/liquid interface. We present data for a 20mM aqueous solutions of 70% cetyltrimethylammonium 3,5-dichlorobenzoate (abbreviated CTA3,5ClBz) and 30% CTAB. This system forms a very viscoelastic solution containing long threadlike micelles. NR only probes to a depth of about 0.5 {mu}m from the surface in these systems and clearly indicates that adsorbed onto the surface is, surfactant layer which is insensitive to shear. The depth probed by the NSSANS is on the order of 20-30 {mu}m and is determined by the transmission of the sample, the angle of incidence, and the wavelength. In this region, the rods align under shear into a remarkably well ordered hexagonal crystal. The SANS from the Couette cell averages over the entire sample, so that the signal is dominated by scattering from the bulk. While the near surface hexagonal structure is clearly visible, these data are not consistent with the crystal structure persisting throughout the bulk, leading to the postulate that the bulk structure is a two dimensional (2D) liquid where the rods align with the flow, but do not order in the other two dimensions.

Butler, P.D.; Hamilton, W.A.; Magid, L.J. [and others

1996-12-31

242

Real-Time Observation of the Solid-Liquid-Vapor Dissolution of Individual Tin(IV) Oxide Nanowires.  

PubMed

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

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

2014-06-24

243

Soins Aux Brules Apres Un Accident Nucleaire  

PubMed Central

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.

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

2010-01-01

244

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)

Oxygen resistive titanium dioxide sensors are useful to control combustion but their studies raise fundamental problems. The non-stoichiometry of titanium dioxide is studied in the 870-1 100 K temperature range by using, out of equilibrium, gas mixture flow of CO, CO2, O2 and Ar. The electrical resistance of sintered samples (dense or porous) or films is measured in steady-state conditions as a function of th gaz flow rate. The deviation to equilibrium increases with the flow rate. The sample resistance is a function of the flow rate, oxygen partial pressure, temperature and microstructure of the specimen. The sensitivity to oxygen is increased by fast oxygen diffusion through the bulk creating a potential barrier at the surface of the grains. Under oxidizing conditions at 870 K, a bulk mechanism determines the resistance variation which is proportional to P_{O_2}^{1/4}/P_{CO}^{1/2}. If reducing conditions are applied, in the same conditions of temperature, the oxide develops a bulk non-stoichiometry which is controlled by the redox couple CO/CO2 assuming thermodynamical equilibrium. However the large number of conducting electrons favors an oxygen chemisorption, creating potential barriers at the surface of the grains. Accordingly the film resistance is a P_{O_2}^{1/2} function. The surface potential and coverage rate are calculated through several theoretical models ; their comparison allows to conclude in a relatively slow diffusion of oxygen vacancies at 870 K. At 1 100 K, the gaz mixture is rather close to thermodynamical equilibrium : in oxidizing medium the sample is equilibrated with oxygen, under CO/CO2 reducing conditions film sensors are only sensitive to oxygen traces. La non-stœchiométrie de l'oxyde de titane est étudiée, dans le domaine de température 870-1 100 K, en présence d'atmosphères hors équilibre thermodynamique, composées de CO, CO2, O2, Ar. La résistance électrique de différentes structures massives, poreuses ou en couches est 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.

Jerisian, R.; Gautron, J.; Loup, J. P.

1992-04-01

245

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

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…

Yalcin, Fatma Aggul

2012-01-01

246

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

NASA Astrophysics Data System (ADS)

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.

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

2012-08-01

247

A Distributed Computing Infrastructure for Computational Thermodynamic Calculations of Solid-Liquid Phase Equilibria  

NASA Astrophysics Data System (ADS)

Software tools like MELTS (Ghiorso and Sack, 1995, CMP 119:197) and its derivatives (Ghiorso et al., 2002, G3 3:10.1029/2001GC000217) are sophisticated calculators used by geoscientists to quantify the chemistry of melt production, transport and storage. These tools utilize computational thermodynamics to evaluate the equilibrium state of the system under specified external conditions by minimizing a suitably constructed thermodynamic potential. Like any thermodynamically based tool, the principal advantage in employing these techniques to model igneous processes is the intrinsic ability to couple the chemistry and energetics of the evolution of the system in a self consistent and rigorous formalism. Access to MELTS is normally accomplished via a standalone X11-based executable or as a Java-based web applet. The latter is a dedicated client-server application rooted at the University of Chicago. Our on-going objective is the development of a distributed computing infrastructure to provide "MELTS-like" computations on demand to remote network users by utilizing a language independent client-server protocol based on CORBA. The advantages of this model are numerous. First, the burden of implementing and executing MELTS computations is centralized with a software implementation optimized to a compute cluster dedicated for that purpose. Improvements and updates to MELTS software are handled locally on the server side without intervention of the user and the server-model lessens the burden of supporting the computational code on a variety of hardware and OS platforms. Second, the client hardware platform does not incur the computational cost of performing a MELTS simulation and the remote user can focus on the task of incorporating results into their model. Third, the client user can write software in a computer language of their choosing and procedural calls to the MELTS library can be executed transparently over the network as if a local language-compatible library of routines is being accessed. Fourth, the flexibility of calling library functions means that the client has more control over the configuration and output of the MELTS calculation. Fifth, if the client computer is a multi-processor compute cluster capable of issuing parallel requests to the MELTS "remote" library, then these requests may be in turn parallelized to the server compute cluster to enhance throughput and performance. Application of this computational model to fluid dynamical simulations of melting and transport in the Earth's mantle is envisioned. Further information and example clients for utilizing the current prototype library for distributed computing applications can be found at http://melts.uchicago.edu.

Ghiorso, M. S.; Kress, V. C.

2004-12-01

248

Temperature responsive flocculation and solid-liquid separations with charged random copolymers of poly(N-isopropyl acrylamide).  

PubMed

Temperature-responsive random copolymers based on poly(N-isopropyl acrylamide) (PNIPAM) with 15 mol% of either acrylic acid or dimethylaminoethyl acrylate quaternary chloride were prepared. The effect of the charge and its sign were investigated in the solid-liquid separation of silica and alumina mineral suspensions. The results were compared to PNIPAM homopolymer of similar molecular weight. PNIPAM copolymers of the same charge as the particles (co-ionic PNIPAM) act as dispersants at both 25°C and 50°C. Flocculation occurs when counter-ionic PNIPAM facilitates selective aggregation and rapid sedimentation of minerals at both 25°C and 50°C. Adsorption and desorption studies showed that, unlike non-ionic PNIPAM, little desorption of the counter-ionic copolymers from the oxides occurred after cooling a suspension from 50°C to below the lower critical solution temperature. Thus, incorporation of counter-ionic charge into the temperature sensitive polymer PNIPAM was found to reduce the sediment bed consolidation upon cooling when compared to PNIPAM homopolymers. The lack of secondary consolidation upon cooling is attributed to attractive inter-particle forces, such as conventional polyelectrolyte flocculation mechanisms (bridging, charge neutralization or charge patch) which persist at both 25°C and 50°C when counter-ionic PNIPAM is used. On the other hand, it was possible to obtain rapid sedimentation with the counter-ionic PNIAPMs even when they were added to the suspension already at 50°C, a process which has not been possible with neutral PNIPAM homopolymers. PMID:21565355

O'Shea, John-Paul; Qiao, Greg G; Franks, George V

2011-08-01

249

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

NASA Astrophysics Data System (ADS)

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.

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

2013-12-01

250

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

PubMed

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

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

2003-10-01

251

Heterogeneous nucleation of calcium phosphate salts at a solid/liquid interface examined by scanning angle reflectometry  

NASA Astrophysics Data System (ADS)

Mineralization of calcium phosphate salts at a solid/liquid silica interface was examined by means of scanning angle reflectometry (SAR). A critical supersaturation of 7.60±0.15 mM was found to be the lowest calcium phosphate concentration at pH 6.85 at which the reflectivity at the Brewster angle started to vary. The analyses of the signals by mean of the homogeneous isotropic layer model led to layer thicknesses of about 3.5 ?m also characterized by very low mean refractive index increments. These observations were completed by complementary experiments. Scanning and transmission electron microscopy led to similar layer thicknesses with crystallites dispersed in the whole layer confirming thus SAR results. X-ray analyses showed a presence of brushite (DCPD) at the silica interface. A pH of 5.44 was estimated for the acidic silica interface for which DCPD is nucleated after addition of 7.60±0.15 mM calcium and phosphate. However, at this pH value, the solution is largely supersaturated with respect to hydroxyapatite (HAP theoretical saturating concentration: 1.37 mM). A faster growth of DCPD crystals compared to HAP crystals is thus assumed to explain our observations.

Ngankam, P. A.; Schaaf, P.; Voegel, J. C.; Cuisinier, F. J. G.

1999-03-01

252

Effects of the thermocapillary convection on the flow stability and on the solid/liquid interface horizontal bridgman growth  

NASA Astrophysics Data System (ADS)

This work concerns the study of the convective instabilities interacting with the solid/liquid interface for a horizontal Bridgman configuration filled with a low Prandtl number material (Pr=0.015). This kind of configuration was the subject of several studies restricted to fluid phase. It was well established the existence of convective oscillatory regime in a tall horizontal cavity. The coupling of such oscillation with phase change (moving interface) was studied by the authors. As most process are with free upper surface, and non-negligible Marangoni effect due to strong applied thermal gradient. We study here the transitions to oscillatory regimes in the presence of thermocapillary convection and the interaction with the solidification/melting front. A computational model based on the enthalpy method and finite volume numerical approximation is developed for this phase change problem. The computed results indicate that the surface tension can play a stabilising role on the flow regime but the interface shape is strongly affected under microgravity conditions. In the same way, the well-chosen growth rate can also contribute to control this directional process.

El Ganaoui, M.; Senna, E.; Bennacer, R.; Bontoux, P.

253

Freezing point and solid-liquid interfacial free energy of Stockmayer dipolar fluids: A molecular dynamics simulation study  

NASA Astrophysics Data System (ADS)

Stockmayer fluids are a prototype model system for dipolar fluids. We have computed the freezing temperatures of Stockmayer fluids at zero pressure using three different molecular-dynamics simulation methods, namely, the superheating-undercooling method, the constant-pressure and constant-temperature two-phase coexistence method, and the constant-pressure and constant-enthalpy two-phase coexistence method. The best estimate of the freezing temperature (in reduced unit) for the Stockmayer (SM) fluid with the dimensionless dipole moment ?*=1, 2, 3 is 0.656 +/- 0.001, 0.726 +/- 0.002, and 0.835 +/- 0.005, respectively. The freezing temperature increases with the dipolar strength. Moreover, for the first time, the solid-liquid interfacial free energies ? of the fcc (111), (110), and (100) interfaces are computed 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, i.e., ?100 > ?110 > ?111.

Wang, Jun; Apte, Pankaj A.; Morris, James R.; Zeng, Xiao Cheng

2013-09-01

254

Freezing point and solid-liquid interfacial free energy of Stockmayer dipolar fluids: a molecular dynamics simulation study.  

PubMed

Stockmayer fluids are a prototype model system for dipolar fluids. We have computed the freezing temperatures of Stockmayer fluids at zero pressure using three different molecular-dynamics simulation methods, namely, the superheating-undercooling method, the constant-pressure and constant-temperature two-phase coexistence method, and the constant-pressure and constant-enthalpy two-phase coexistence method. The best estimate of the freezing temperature (in reduced unit) for the Stockmayer (SM) fluid with the dimensionless dipole moment ?*=1, ?2, ?3 is 0.656 ± 0.001, 0.726 ± 0.002, and 0.835 ± 0.005, respectively. The freezing temperature increases with the dipolar strength. Moreover, for the first time, the solid-liquid interfacial free energies ? of the fcc (111), (110), and (100) interfaces are computed 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, i.e., ?100 > ?110 > ?111. PMID:24070303

Wang, Jun; Apte, Pankaj A; Morris, James R; Zeng, Xiao Cheng

2013-09-21

255

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

PubMed

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

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

2012-10-23

256

L’influence du degré d’aversion à l’inégalité du décideur sur sa perception des inégalités intragroupes et intergroupes : une application de l’alpha décomposition aux salaires de la France entre 1995 et 2005  

Microsoft Academic Search

Nous proposons dans cette recherche de mettre en avant le rôle capital joué par les préférences du décideur sur sa perception des inégalités intragroupes et intergroupes. Une application réalisée à partir des salaires observés en France entre 1995 et 2005 révèle notamment de grands écarts de valeurs entre les différents indicateurs choisis pour évaluer l’évolution des disparités salariales sur la

Pauline MORNET; Françoise SEYTE; Michel TERRAZA

2012-01-01

257

Solid-liquid coexistence in small systems: A statistical method to calculate melting temperatures  

NASA Astrophysics Data System (ADS)

We propose an efficient and accurate scheme to calculate the melting point (MP) of materials. This method is based on the statistical analysis of small-size coexistence molecular dynamics simulations. It eliminates the risk of metastable superheated solid in the fast-heating method, while also significantly reducing the computer cost relative to the traditional large-scale coexistence method. Using empirical potentials, we validate the method and systematically study the finite-size effect on the calculated MPs. The method converges to the exact result in the limit of large system size. An accuracy within 100 K in MP is usually achieved when simulation contains more than 100 atoms. Density functional theory examples of tantalum, high-pressure sodium, and ionic material NaCl are shown to demonstrate the accuracy and flexibility of the method in its practical applications. The method serves as a promising approach for large-scale automated material screening in which the MP is a design criterion.

Hong, Qi-Jun; van de Walle, Axel

2013-09-01

258

Interactions of PAMAM dendrimers with SDS at the solid-liquid interface.  

PubMed

This work addresses structural and nonequilibrium effects of the interactions between well-defined cationic poly(amidoamine) PAMAM dendrimers of generations 4 and 8 and the anionic surfactant sodium dodecyl sulfate (SDS) at the hydrophilic silica-water interface. Neutron reflectometry and quartz crystal microbalance with dissipation monitoring were used to reveal the adsorption from premixed dendrimer/surfactant solutions as well as sequential addition of the surfactant to preadsorbed layers of dendrimers. PAMAM dendrimers of both generations adsorb to hydrophilic silica as a compact monolayer, and the adsorption is irreversible upon rinsing with salt solution. SDS adsorbs on the dendrimer layer and at low bulk concentrations causes the expansion of the dendrimer layers on the surface. When the bulk concentration of SDS is increased, the surfactant layer consists of aggregates or bilayer-like structures. The adsorption of surfactant is reversible upon rinsing, but slight changes of the structure of the preadsorbed PAMAM monolayer were observed. The adsorption from premixed solutions close to charge neutrality results in thick multilayers, but the surface excess is lower when the bulk complexes have a net negative charge. A critical examination of the pathway of adsorption for the interactions of SDS with preadsorbed PAMAM monolayers and premixed PAMAM/SDS solutions with hydrophilic silica revealed that nonequilibrium effects are important only in the latter case, and the application of a thermodynamic model to such experimental data would be inappropriate. PMID:23556998

Arteta, Marianna Yanez; Eltes, Felix; Campbell, Richard A; Nylander, Tommy

2013-05-14

259

Solid-liquid extraction of alkali metals and organic compounds by leaching of food industry residues.  

PubMed

Leaching was studied for its application in extracting inorganic and organic constituents from fresh fermented grape pomace, air-dried fermented grape pomace and air-dried sugar beet pulp. Samples of each feedstock were leached in water at ambient temperature for 30 or 120 min at dry solid-to-liquid ratios of 1/20 and 1/50 kg/L. Leaching removed 82% of sodium, 86% of potassium, and 76% of chlorine from sugar beet pulp, and reduced total ash concentration in air-dry fermented grape pomace from 8.2% to 2.9% of dry matter, 8.2% to 4.4% in fresh fermented grape pomace, and 12.5% to 5.4% in sugar beet pulp. Glycerol (7-11 mg/dry g), ethanol (131-158 mg/dry g), and acetic acid (24-31 mg/dry g) were also extracted from fermented grape pomace. These results indicate that leaching is a beneficial pretreatment step for improving the quality of food processing residues for thermochemical and biochemical conversion. PMID:20153641

Yu, Chaowei; Zheng, Yi; Cheng, Yu-Shen; Jenkins, Bryan M; Zhang, Ruihong; VanderGheynst, Jean S

2010-06-01

260

Changes in auxin response from mutations in an AUX/IAA gene.  

PubMed

Transcription of the AUX/IAA family of genes is rapidly induced by the plant hormone auxin, but evidence that AUX/IAA genes mediate further responses to auxin has been elusive. Changes in diverse auxin responses result from mutations in the Arabidopsis AXR3 gene. AXR3 was shown to be a member of the AUX/IAA family, providing direct evidence that AUX/IAA genes are central in auxin signaling. Molecular characterization of axr3 gain-of-function and loss-of-function mutations established the functional importance of domains conserved among AUX/IAA proteins. PMID:9478901

Rouse, D; Mackay, P; Stirnberg, P; Estelle, M; Leyser, O

1998-02-27

261

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

SciTech Connect

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.

Kabadi, V.N.

1995-06-30

262

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

SciTech Connect

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.

Kabadi, V.N.; Ilias, S.

1992-12-31

263

Adsorption at the solid-liquid interface as the source of contact angle dependence on the curvature of the three-phase line.  

PubMed

We review the thermodynamic approach to determining the surface tension of solid-fluid interfaces. If the pressure is in the narrow range where the contact angle, ?, can exist, then for isothermal systems, adsorption at the solid-liquid interface affects ?(SL) or ?, but ?(SV) is very nearly equal ?(LV), the surface tension of the adsorbing fluid. For a liquid partially filling a cylinder, the pressure in the liquid phase at the three-phase line, x(3)(L), depends on the curvature of the three-phase line, C(cl), but the line tension can play no role, since it acts perpendicular to the cylinder wall. C(cl) is decreased as the cylinder diameter is increased; x(3)(L) is increased; and ? increases. For a given value of C(cl), x(3)(L) can be changed by rotating the cylinder or by changing the height of the three-phase line in a gravitational field. In all cases, for water in borosilicate glass cylinders, the value of ? is shown to increase as x(3)(L) is increased. This behaviour requires the Gibbsian adsorption at the solid-liquid interface to be negative, indicating the liquid concentration in the interphase is less than that in the bulk liquid. For sessile droplets, the value of ? depends on both x(3)(L) and C(cl). If the value of ? for spherical sessile droplets is measured as a function of C(cl), the adsorption at the solid-liquid interface that would give that dependence can be determined. It is unnecessary to introduce the line tension hypothesis to explain the dependence of ? on C(cl). Adsorption at the solid-liquid interface gives a full explanation. PMID:19931850

Ward, C A; Sefiane, K

2010-12-15

264

X-ray and neutron surface scattering for studying lipidrpolymer assemblies at the air)liquid and solid)liquid interfaces  

Microsoft Academic Search

Simple mono- and bilayers, built of amphiphilic molecules and prepared at air)liquid or solid)liquid interfaces, can be used as models to study such effects as water penetration, hydrocarbon chain packing, and structural changes due to head group modification. In the paper, we will discuss neutron and X-ray reflectometry and grazing incidence X-ray diffraction techniques used to explore structures of such

Jaroslaw Majewski; Tonya L. Kuhl; Joyce Y. Wong; Gregory S. Smith

265

2D analogues of the inverted hexagonal phase self-assembled from 4,6-dialkoxylated isophthalic acids at solid-liquid interfaces  

Microsoft Academic Search

Self-assembly of organic molecules at solid-liquid interfaces is a route for developing novel functional materials on surfaces and modeling assembly phenomena in 3D. 5-Alkoxylated isophthalic acids (ISA) are known to self-assemble into two-dimensional (2D) lamellae at the interface between a surface of Au(111) or HOPG (highly oriented pyrolytic graphite) and a solvent. Presently, the self-assembly of 4,6-dialkoxylated isophthalic acid derivatives

Andrey S. Klymchenko; Shuhei Furukawa; Tanya Balandina; Klaus Müllen; Mark van der Auweraer; Steven de Feyter

2010-01-01

266

Solid–liquid equilibrium and hydrogen solubility of trans-decahydronaphthalene + naphthalene and cis-decahydronaphthalene + naphthalene for a new hydrogen storage medium in fuel cell system  

Microsoft Academic Search

Solid–liquid equilibrium was measured for benzene+cyclohexane, trans-decahydronaphthalene+naphthalene and cis-decahydronaphthalene+naphthalene under the atmospheric pressure in the temperature range from 226.69 to 353.14K. The apparatus was specially designed in this study, and it was based on a cooling method. The phase diagram with the complete immiscible solids was observed for the three systems, and the eutectic point was found at x2=0.2709 and

Tomoya Tsuji; Kiwamu Sue; Toshihiko Hiaki; Naotsugu Itoh

2007-01-01

267

Synthesis of nanosized Si particles via a mechanochemical solid–liquid reaction and application in Li-ion batteries  

Microsoft Academic Search

Nanosized silicon particles were obtained by reaction between SiBr4 solution and Mg granules during a ball-milling process. X-ray diffraction measurements show that crystallized silicon was obtained after 20 h of milling, together with MgBr2, non-reacted Mg and probably SiOx. The powder was subjected to a suitable cleaning treatment in order to minimize the proportion of residual products. The different analyses carried

I. Sandu; P. Moreau; D. Guyomard; T. Brousse; L. Roué

2007-01-01

268

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

NASA Astrophysics Data System (ADS)

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.

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

2014-06-01

269

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

PubMed

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 ?=275nm, the fluorescence emission intensity of melatonin was measured at ?=366nm. 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?gmL(-1), with a detection limit of 0.0036?gmL(-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. PMID:24878439

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

2014-11-11

270

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

PubMed

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

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

2014-06-01

271

Activated carbon surface heterogeneity seen by parallel probing by inverse liquid chromatography at the solid\\/liquid interface and by gas adsorption analysis at the solid\\/gas interface  

Microsoft Academic Search

The energetic surface heterogeneity of four different activated carbons was assessed by the parallel probing at the solid\\/liquid and solid\\/gas interfaces. At the solid\\/liquid interface a method of inverse liquid chromatography, frontal analysis by characteristic point was applied using phenylalanine in water solution as a probe molecule. At the solid\\/gas interface, argon was used as a probe in the low

C. Garnier; T. Görner; F. Villiéras; Ph. De Donato; M. Polakovi?; J.-L. Bersillon; L. J. Michot

2007-01-01

272

Sequence stratigraphy of the Aux Vases Sandstone: A major oil producer in the Illinois basin  

USGS Publications Warehouse

The Aux Vases Sandstone (Mississippian) has contributed between 10 and 25% of all the oil produced in Illinois. The Aux Vases is not only an important oil reservoir but is also an important source of groundwater, quarrying stone, and fluorspar. Using sequence stratigraphy, a more accurate stratigraphic interpretation of this economically important formation can be discerned and thereby enable more effective exploration for the resources contained therein. Previous studies have assumed that the underlying Spar Mountain, Karnak, and Joppa formations interfingered with the Aux Vases, as did the overlying Renault Limestone. This study demonstrates that these formations instead are separated by sequence boundaries; therefore, they are not genetically related to each other. A result of this sequence stratigraphic approach is the identification of incised valleys, paleotopography, and potential new hydrocarbon reservoirs in the Spar Mountain and Aux Vases. In eastern Illinois, the Aux Vases is bounded by sequence boundaries with 20 ft (6 m) of relief. The Aux Vases oil reservoir facies was deposited as a tidally influenced siliciclastic wedge that prograded over underlying carbonate-rich sediments. The Aux Vases sedimentary succession consists of offshore sediment overlain by intertidal and supratidal sediments. Low-permeability shales and carbonates typically surround the Aux Vases reservoir sandstone and thereby form numerous bypassed compartments from which additional oil can be recovered. The potential for new significant oil fields within the Aux Vases is great, as is the potential for undrained reservoir compartments within existing Aux Vases fields.

Leetaru, H. E.

2000-01-01

273

Article 45 de la loi n° 2005-102 du 11 février 2005 pour l'égalité des droits et des chances, la participation et la citoyenneté des personnes handicapées. Propositions pour l'application aux transports collectifs du Département de la Nièvre  

Microsoft Academic Search

La loi n° 2005-102 du 11 février 2005 vise à donner une nouvelle impulsion à la lutte contre les discriminations vis à vis des personnes handicapées ou à mobilité réduite. Pour cela, le législateur impose la mise en accessibilité de toute la chaîne de déplacement à l'horizon 2015. Cette loi s'adresse en priorité aux Autorités Organisatrices des Transports chargée de

Xavier Badia

2006-01-01

274

Industrie manufacturière : de l'investissement aux capacités de production  

Microsoft Academic Search

[fre] Industrie manufacturière : de l'investissement aux capacités de production . Dès le début de l'année 1 994, l'activité industrielle a bénéficié d'une reprise très vigoureuse. En revanche, la reprise de l'investissement semble tarder à se développer. Dans ce contexte, les capacités de production industrielles seront-elles suffisantes pour consolider la croissance et autoriser son accélération ? . Les flux d'investissement

Séverine Mayo; Marie Reynaud

1995-01-01

275

Application de la combustion catalytique aux turbines à gaz  

Microsoft Academic Search

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

E. Lebas; G. H. Martin

2002-01-01

276

Évaluation de la performance péréquatrice des concours financiers de l'État aux communes  

Microsoft Academic Search

[fre] Évaluation de la performance péréquatrice des concours financiers de l’État aux communes . . Les 36 600 communes françaises sont loin de pouvoir offrir aux résidents ou aux entreprises qu’elles accueillent le même niveau de services collectifs de proximité pour un effort fiscal donné. Leurs «pouvoirs d’achat en termes de consommations collectives» varient dans des proportions considérables. D’une part,

Guy Gilbert; Alain Guengant

2004-01-01

277

Auxin regulates SCFTIR1-dependent degradation of AUX\\/IAA proteins  

Microsoft Academic Search

The plant hormone auxin is central in many aspects of plant development. Previous studies have implicated the ubiquitin-ligase SCFTIR1 and the AUX\\/IAA proteins in auxin response. Dominant mutations in several AUX\\/IAA genes confer pleiotropic auxin-related phenotypes, whereas recessive mutations affecting the function of SCFTIR1 decrease auxin response. Here we show that SCFTIR1 is required for AUX\\/IAA degradation. We demonstrate that

William M. Gray; Stefan Kepinski; Dean Rouse; Ottoline Leyser; Mark Estelle

2001-01-01

278

Le problème de la fusion de coopératives agricoles aux Etats-Unis  

Microsoft Academic Search

[fre] Le gouvernement américain poursuit une politique favorable à la création et à la croissance des coopératives agricoles. . Avant d'opérer une fusion, les coopératives doivent d'abord résoudre les problèmes relatifs aux personnes et aux finances ; les plus grandes peuvent rencontrer des difficultés juridiques dues aux lois anti-trusts. L'efficacité est la condition essentielle du succès de l'intégration. . Il

Hugh L. Cook

1965-01-01

279

Localized Iron Supply Triggers Lateral Root Elongation in Arabidopsis by Altering the AUX1-Mediated Auxin Distribution[C][W][OA  

PubMed Central

Root system architecture depends on nutrient availability, which shapes primary and lateral root development in a nutrient-specific manner. To better understand how nutrient signals are integrated into root developmental programs, we investigated the morphological response of Arabidopsis thaliana roots to iron (Fe). Relative to a homogeneous supply, localized Fe supply in horizontally separated agar plates doubled lateral root length without having a differential effect on lateral root number. In the Fe uptake-defective mutant iron-regulated transporter1 (irt1), lateral root development was severely repressed, but a requirement for IRT1 could be circumvented by Fe application to shoots, indicating that symplastic Fe triggered the local elongation of lateral roots. The Fe-stimulated emergence of lateral root primordia and root cell elongation depended on the rootward auxin stream and was accompanied by a higher activity of the auxin reporter DR5-?-glucuronidase in lateral root apices. A crucial role of the auxin transporter AUXIN RESISTANT1 (AUX1) in Fe-triggered lateral root elongation was indicated by Fe-responsive AUX1 promoter activities in lateral root apices and by the failure of the aux1-T mutant to elongate lateral roots into Fe-enriched agar patches. We conclude that a local symplastic Fe gradient in lateral roots upregulates AUX1 to accumulate auxin in lateral root apices as a prerequisite for lateral root elongation.

Giehl, Ricardo F.H.; Lima, Joni E.; von Wiren, Nicolaus

2012-01-01

280

Mixing and solid-liquid mass-transfer rates in a creusot-loire uddeholm vessel: A water model case study  

Microsoft Academic Search

The process of mixing and solid-liquid mass transfer in a one-fifth scale water model of a 100-ton Creusot-Loire Uddeholm\\u000a (CLU) converter was investigated. The modified Froude number was used to relate gas flow rates between the model and its protoype.\\u000a The influences of gas flow rate between 0.010 and 0.018 m3\\/s and bath height from 0.50 to 0.70 m on

M. Nyoka; G. Akdogan; R. H. Eric; N. Sutcliffe

2003-01-01

281

Solid-liquid phase equilibria in binary (benzene, cyclohexane + n-tetradecane, n-hexadecane) systems at temperatures 230–323 K and pressures up to 120 MPa  

Microsoft Academic Search

The solid-liquid phase behavior has been measured for the binary systems (C6H6 + n-C14H30), (C6H6 + n-C16H34), (C6H12 + n-C14H30), and (C6H12 + n-C16H34) at temperatures from 230 to 323 K and pressures up to 120 MPa by the visual observation of the phase transition using a high-pressure optical vessel with the aid of a video microscope. The uncertainties in

Y. Tanaka; M. Kawakami

1996-01-01

282

Solid–liquid and liquid–liquid equilibria for 1,3,5-trioxane, or 1,4,7,10,13,16-hexaoxacyclooctadecane + selected n-alkane mixtures  

Microsoft Academic Search

Solid–liquid and liquid–liquid equilibrium temperatures for mixtures of 1,3,5-trioxane, or 1,4,7,10,13,16-hexaoxacyclooctadecane with n-heptane, or with n-tridecane, or with n-hexadecane are reported. The equilibrium temperatures were measured by a dynamic method. Mixtures with n-tridecane, or n-hexadecane show a eutectic point. 1,4,7,10,13,16-Hexaoxacyclooctadecane present a transition point in solid phase, which depends on the solvent. Dipole–dipole interactions are stronger in solutions with 1,3,5-trioxane.Mixtures

U. Domanska; J. A. González

2003-01-01

283

Local viscosity change in water near a solid-liquid interface and its extraction by means of molecular rotational diffusion - A molecular dynamics study  

NASA Astrophysics Data System (ADS)

The relation between the rotational diffusion (RD) coefficient of water molecules and viscosity, that theoretically are inversely proportional to each other, was examined by using molecular dynamics simulations. In a homogeneous bulk liquid system, both the viscosity calculated from the virial theorem and the experimental one correlated well with the inverse of water RD coefficient at various temperatures. In a heterogeneous system of water between solid walls with different solid-liquid interaction strength, the viscosity distribution was similar to the distribution of the RD coefficient inverse multiplied by density, and this suggests the possibility of extracting nanometer-scale viscosity distribution by RD.

Nakaoka, Satoshi; Surblys, Donatas; Yamaguchi, Yasutaka; Kuroda, Koji; Nakajima, Tadashi; Fujimura, Hideo

2014-01-01

284

Expression and regulation of the early auxin-responsive Aux/IAA genes during strawberry fruit development.  

PubMed

The plant hormone auxin transcriptionally activates Aux/IAA genes. Auxin plays an important role in regulating fruit growth and ripening of strawberry and Aux/IAA genes have been extensively studied in Arabidopsis, rice and tomato, but little information is available on strawberry fruit. In the present work, two full-length of early auxin-responsive Aux/IAA genes, termed FaAux/IAA1 and FaAux/IAA2 respectively, were isolated and characterized from strawberry fruit. Moreover, the expression profiles of two FaAux/IAA genes during fruit development, and the effect of naphthalene acetic acid (NAA) on their expressions of fruits at two different developmental stages were also investigated. The results showed that the levels of FaAux/IAA1 and FaAux/IAA2 transcripts were very high at early stage of fruit development, and decreased sharply at ripening stage (after white stage). In addition, NAA applied at the stage of large green and white fruit obviously increased the accumulations of FaAux/IAA1 and FaAux/IAA2 transcripts. These data suggested that the expressions of both FaAux/IAA1 and FaAux/IAA2 genes were likely to be involved in early fruit development, and the enhancement of FaAux/IAAs transcripts might be attributed at least or partially to auxin-induced fruit growth and delayed fruit ripening of strawberry. PMID:20563652

Liu, Du-juan; Chen, Jian-ye; Lu, Wang-jin

2011-02-01

285

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)

Slow pyrolysis is a well established technology for converting biomass into a more stable form of carbon (biochar) while also producing energy rich by-products of bio-oil and syngas. Biochar is the porous, carbonaceous material produced by thermo-chemical treatment of organic materials in an oxygen-limited environment. Biochar can be incorporated into soils to improve soil fertility, reduce greenhouse gas emissions as well as provide long term storage of carbon or alternatively it can also provide additional energy to a pyrolysis system through combustion. Biochar production conditions have a significant influence on the yield as well as physiochemical and functional properties of the final pyrolysis products, resulting in a selection process aimed towards either agricultural benefits and carbon mitigation or heat/energy generation. This work aimed to investigate the effect of temperature, residence time and gas flow rate on the product energy distribution as well as the physical, chemical and soil functional properties of biochar, in order to optimise conditions best suited to maximise both energy value and agronomic benefit. Biochar samples were produced from wood pellets (WP) and straw pellets (SP) at two temperatures (350 and 650oC), with three residence times (10, 20 and 40 minutes) and three carrier gas flow rates (0, 0.3 and 0.6 L min-1). The energy balance of the system was determined through the calorimetric analysis of biochar and bio-oil, while the higher heating value for the syngas was calculated from the gas composition measured via mass spectroscopy. Biochar was also analysed for the physiochemical properties of proximate analysis and ultimate analysis as well as the functional property of environmentally stable carbon (C) content. As expected the yield of biochar decreased with increasing temperature resulting in elevated yields of liquid and gas fractions. Increased temperature also resulted in higher values of fixed C, total C, stable C and 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.

Crombie, Kyle; Masek, Ondrej

2013-04-01

286

Finite element analysis of the effect of a non-planar solid-liquid interface on the lateral solute segregation during unidirectional solidification  

NASA Technical Reports Server (NTRS)

The effect of solid-liquid interface shape on lateral solute segregation during steady-state unidirectional solidification of a binary mixture is calculated under the assumption of no convection in the liquid. A finite element technique is employed to compute the concentration field in the liquid and the lateral segregation in the solid with a curved boundary between the liquid and solid phases. The computational model is constructed assuming knowledge of the solid-liquid interface shape; no attempt is made to relate this shape to the thermal field. The influence of interface curvature on the lateral compositional variation is investigated over a range of system parameters including diffusivity, growth speed, distribution coefficient, and geometric factors of the system. In the limiting case of a slightly nonplanar interface, numerical results from the finite element technique are in good agreement with the analytical solutions of Coriell and Sekerka obtained by using linear theory. For the general case of highly non-planar interface shapes, the linear theory fails and the concentration field in the liquid as well as the lateral solute segregation in the solid can be calculated by using the finite element method.

Carlson, F. M.; Chin, L.-Y.; Fripp, A. L.; Crouch, R. K.

1982-01-01

287

Mixing and solid-liquid mass-transfer rates in a creusot-loire uddeholm vessel: A water model case study  

NASA Astrophysics Data System (ADS)

The process of mixing and solid-liquid mass transfer in a one-fifth scale water model of a 100-ton Creusot-Loire Uddeholm (CLU) converter was investigated. The modified Froude number was used to relate gas flow rates between the model and its protoype. The influences of gas flow rate between 0.010 and 0.018 m3/s and bath height from 0.50 to 0.70 m on mixing time were examined. The results indicated that mixing time decreased with increasing gas flow rate and increased with increasing bath height. The mixing time results were evaluated in terms of specific energy input and the following correlation was proposed for estimating mixing times in the model CLU converter: T mix=1.08Q -1.05 W 0.35, where Q (m3/s) is the gas flow rate and W (tons) is the model bath weight. Solid-liquid mass-transfer rates from benzoic acid specimens immersed in the gas-agitated liquid phase were assessed by a weight loss measurement technique. The calculated mass-transfer coefficients were highest at the bath surface reaching a value of 6.40 × 10-5 m/s in the sprout region. Mass-transfer coefficients and turbulence parameters decreased with depth, reaching minimum values at the bottom of the vessel.

Nyoka, M.; Akdogan, G.; Eric, R. H.; Sutcliffe, N.

2003-12-01

288

Ultrasound assisted arylation of benzyl alcohol with 4-nitrochlorobenzene under a new multi-site phase-transfer catalyst in solid-liquid condition.  

PubMed

The ultrasound assisted preparation of 1-(benzyloxy)-4-nitrobenzene from the reaction of 4-chloronitrobenzene (CNB) and benzyl alcohol was carried out successfully using potassium hydroxide and catalyzed by a new multi-site phase-transfer catalyst (MPTC) viz., 1,3,5-triethyl-1,3,5-trihexyl-1,3,5-triazinane-1,3,5-triium trichloride in a solid-liquid reaction condition (SL-MPTC). The advantage of using SL-MPTC is to avoid a serious hydration of potassium salt of benzyl alcohol in the reaction between 4-chloronitrobenzene (CNB) and benzyl alcohol. The reaction is greatly enhanced in the solid-liquid system, catalyzed by multi-site quaternary ammonium salt (MPTC) and ultrasound irradiation (40kHz, 300W) in a batch reactor, it shows that the overall reaction greatly enhanced with ultrasound irradiation than without ultrasound. The reaction mechanism is proposed and verified by examining the experimental evidence. A kinetic model is proposed in which a pseudo first-order rate law is sufficient to describe the results, such as the effects of agitation speed, ultrasound, different phase transfer catalysts and the effect of organic solvents, the amount of newly prepared MPTC, the effect of temperature, the amount of water, the concentration of 4-chloronitrobenzene (CNB) and potassium hydroxide concentrations. The apparent rate constant (kapp) were investigated in detail. Rational explanations to account for the phenomena on the results were made. PMID:24830817

Selvaraj, Varathan; Abimannan, Pachaiyappan; Rajendran, Venugopal

2014-09-01

289

Structure-Function Analysis of the Presumptive Arabidopsis Auxin Permease AUX1W?  

PubMed Central

We have investigated the subcellular localization, the domain topology, and the amino acid residues that are critical for the function of the presumptive Arabidopsis thaliana auxin influx carrier AUX1. Biochemical fractionation experiments and confocal studies using an N-terminal yellow fluorescent protein (YFP) fusion observed that AUX1 colocalized with plasma membrane (PM) markers. Because of its PM localization, we were able to take advantage of the steep pH gradient that exists across the plant cell PM to investigate AUX1 topology using YFP as a pH-sensitive probe. The YFP-coding sequence was inserted in selected AUX1 hydrophilic loops to orient surface domains on either apoplastic or cytoplasmic faces of the PM based on the absence or presence of YFP fluorescence, respectively. We were able to demonstrate in conjunction with helix prediction programs that AUX1 represents a polytopic membrane protein composed of 11 transmembrane spanning domains. In parallel, a large aux1 allelic series containing null, partial-loss-of-function, and conditional mutations was characterized to identify the functionally important domains and amino acid residues within the AUX1 polypeptide. Whereas almost all partial-loss-of-function and null alleles cluster in the core permease region, the sole conditional allele aux1-7 modifies the function of the external C-terminal domain.

Swarup, Ranjan; Kargul, Joanna; Marchant, Alan; Zadik, Daniel; Rahman, Abidur; Mills, Rebecca; Yemm, Anthony; May, Sean; Williams, Lorraine; Millner, Paul; Tsurumi, Seiji; Moore, Ian; Napier, Richard; Kerr, Ian D.; Bennett, Malcolm J.

2004-01-01

290

Auxin regulates SCF(TIR1)-dependent degradation of AUX/IAA proteins.  

PubMed

The plant hormone auxin is central in many aspects of plant development. Previous studies have implicated the ubiquitin-ligase SCF(TIR1) and the AUX/IAA proteins in auxin response. Dominant mutations in several AUX/IAA genes confer pleiotropic auxin-related phenotypes, whereas recessive mutations affecting the function of SCF(TIR1) decrease auxin response. Here we show that SCF(TIR1) is required for AUX/IAA degradation. We demonstrate that SCF(TIR1) interacts with AXR2/IAA7 and AXR3/IAA17, and that domain II of these proteins is necessary and sufficient for this interaction. Further, auxin stimulates binding of SCF(TIR1) to the AUX/IAA proteins, and their degradation. Because domain II is conserved in nearly all AUX/IAA proteins in Arabidopsis, we propose that auxin promotes the degradation of this large family of transcriptional regulators, leading to diverse downstream effects. PMID:11713520

Gray, W M; Kepinski, S; Rouse, D; Leyser, O; Estelle, M

2001-11-15

291

Effect of end-group modification on the adsorption of poly(ethylene oxide)-b-poly(butylene oxide) diblock copolymers at the solid–liquid interface  

Microsoft Academic Search

The adsorption of poly(ethylene oxide)-b-poly(butylene oxide) diblock copolymers at the solid–liquid interface was studied\\u000a using a quartz crystal microbalance with dissipation monitoring (QCM-D). The effect of modifying the end group of the hydrophilic\\u000a block was investigated by comparing the behaviour of trimethylammonium- and dimethylamino-tipped copolymers, designated as\\u000a TE\\u000a m\\u000a B\\u000a n\\u000a and DE\\u000a m\\u000a B\\u000a n\\u000a , respectively. For adsorption

Mohammad Siddiq; Guangming Liu; Guangzhao Zhang; Abbas Khan; Peter M. Budd

2010-01-01

292

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)

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 8 GPa. This assembly is especially useful for precise elasticity measurements of single-crystal samples under hydrostatic compression.

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

2005-03-01

293

From solid-vacuum to solid-gas and solid-liquid interfaces: In situ studies of structure and dynamics under relevant conditions  

NASA Astrophysics Data System (ADS)

Surface science instrumentation usually requires working under high vacuum. But in many cases the surface reactivity and structure in real environments can be dramatically different from that measured in this pressure range, where traditional atomic scale studies have been carried out. In this paper we briefly describe some techniques that have been improved to work under high pressures of gases or with liquids. Examples of recent research studies on solid-liquid and solid-gas interfaces are shown. The possibility to work with these instruments under realistic conditions to obtain information in situ during reactions or processes can have a great impact in heterogeneous catalysis, fuel cells, photovoltaics, batteries, corrosion, biological systems and many other fields.

Escudero, Carlos; Salmeron, Miquel

2013-01-01

294

Determination of spinosad at trace levels in bee pollen and beeswax with solid-liquid extraction and LC-ESI-MS.  

PubMed

This paper reports the use of a new LC method with a fused-core analytical column coupled to ESI-MS to determine residues of the biopesticide spinosad in bee pollen and beeswax. The method analyzes the active ingredients, spinosyns A and D, with a simple and efficient sample treatment (recovery between 90 and 105%) consisting of a solid-liquid extraction with acetone (bee pollen) or acetonitrile (beeswax). The method was validated in terms of selectivity, LOD, LOQ, linearity, and precision. The LOD and LOQ values ranged between 0.1-0.2 and 0.4-0.7 ?g/kg, respectively. Moreover, the precision obtained within the linear concentration range (LOQ 500 ?g/kg) was satisfactory (RSD lower than 5%). Finally, the proposed method was applied to analyze bee pollen and beeswax samples collected from apiaries located close to fruit orchards in two Spanish regions. PMID:24243865

Yáñez, Karen P; Martín, María T; Bernal, José L; Nozal, María J; Bernal, José

2014-02-01

295

The isoelectric point/point-of zero-charge of interfaces formed by aqueous solutions and nonpolar solids, liquids, and gases.  

PubMed

From our previous work on the role of the electrostatic field strength in controlling the pH of the iso-electric point (iep)/point-of-zero-charge (pzc) of polar solids we have extended the analysis to predict that the pH of the iep/pzc of a nonpolar solid, liquid or gas-aqueous interface should occur at pH 1.0-3.0, dependent on the value assigned to water molecules or clusters at the interface. Consideration of a wide range of experimental results covering nonpolar solids such as molybdenite, stibnite, paraffin, etc. as well as hydrocarbon liquids such as xylene, decalin, and long chain (>C8) alkane oils, as well as nitrogen and hydrogen gases, all in various simple 1:1 electrolyte solutions confirm the general validity of the result. We further consider various models of the origin of the charge on nonpolar material-water interfaces. PMID:17316674

Healy, Thomas W; Fuerstenau, Douglas W

2007-05-01

296

Local atomic order in the melt and solid-liquid interface effect on the growth kinetics in a metallic alloy model.  

PubMed

We illustrate for a solid-liquid interface how local atomic order in a metallic melt (NiZr) transforms into a massive in-plane ordering at the surface of a crystal (bcc Zr) when commensurability is given between the solute-centered clusters of the melt and the periodic potential of the crystalline surface for a given orientation. Linking molecular dynamics simulation to phase-field modeling allows us to estimate quantitatively the influence of the surface effect on the growth kinetics. This study sheds new light on the relation between the undercooling ability (e.g., in the case of glass-forming alloys) and the pronounced local order in the melt. PMID:23473171

Guerdane, M; Teichler, H; Nestler, B

2013-02-22

297

Local Atomic Order in the Melt and Solid-Liquid Interface Effect on the Growth Kinetics in a Metallic Alloy Model  

NASA Astrophysics Data System (ADS)

We illustrate for a solid-liquid interface how local atomic order in a metallic melt (NiZr) transforms into a massive in-plane ordering at the surface of a crystal (bcc Zr) when commensurability is given between the solute-centered clusters of the melt and the periodic potential of the crystalline surface for a given orientation. Linking molecular dynamics simulation to phase-field modeling allows us to estimate quantitatively the influence of the surface effect on the growth kinetics. This study sheds new light on the relation between the undercooling ability (e.g., in the case of glass-forming alloys) and the pronounced local order in the melt.

Guerdane, M.; Teichler, H.; Nestler, B.

2013-02-01

298

Performance and techno-economic assessment of several solid-liquid separation technologies for processing dilute-acid pretreated corn stover.  

PubMed

Solid-liquid separation of pretreated lignocellulosic biomass slurries is a critical unit operation employed in several different processes for production of fuels and chemicals. An effective separation process achieves good recovery of solute (sugars) and efficient dewatering of the biomass slurry. Dilute acid pretreated corn stover slurries were subjected to pressure and vacuum filtration and basket centrifugation to evaluate the technical and economic merits of these technologies. Experimental performance results were used to perform detailed process simulations and economic analysis using a 2000tonne/day biorefinery model to determine differences between the various filtration methods and their process settings. The filtration processes were able to successfully separate pretreated slurries into liquor and solid fractions with estimated sugar recoveries of at least 95% using a cake washing process. A continuous vacuum belt filter produced the most favorable process economics. PMID:24995879

Sievers, David A; Tao, Ling; Schell, Daniel J

2014-09-01

299

Formation of the racemic compound of ephedrine base from a physical mixture of its enantiomers in the solid, liquid, solution, or vapor state.  

PubMed

Physical mixtures (conglomerates) of the two enantiomers of ephedrine base, each containing 0.5% (w/w) of water, were observed to be converted to the 1:1 racemic compound in the solid, liquid, solution, or vapor state. From a geometrically mixed racemic conglomerate of particle size 250-300 microns (50-60 mesh), the formation of the racemic compound follows second-order kinetics (first order with respect to each enantiomer), with a rate constant of 392 mol-1 hr-1 at 22 degrees C. The reaction appears to proceed via the vapor phase as indicated by the growth of the crystals of the racemic compound between diametrically separated crystals of the two enantiomers in a glass petri dish. The observed kinetics of conversion in the solid state are explained by a homogeneous reaction model via the vapor and/or liquid states. Formation of the racemic compound from the crystals of ephedrine enantiomers in the solution state may explain why Schmidt et al. (Pharm. Res. 5:391-395, 1988) observed a consistently lower aqueous solubility of the mixture than of the pure enantiomers. The solid phase in equilibrium with the solution at the end of the experiment was found to be the racemic compound, whose melting point and heat of fusion are higher than those of the enantiomers. An association reaction, of measurable rate, between the opposite enantiomers in a binary mixture in the solid, liquid, solution, or vapor state to form the racemic compound may be more common than is generally realized. PMID:1409382

Duddu, S P; Grant, D J

1992-08-01

300

The aux1 Mutation of Arabidopsis Confers Both Auxin and Ethylene Resistance 12  

PubMed Central

Mutagenized populations of Arabidopsis thaliana seedlings were screened for plants capable of root growth on inhibitory concentrations of the ethylene precursor 1-aminocyclopropane-1-carboxylic acid. Four of the mutant lines recovered from this screen display a defect in root gravitropism as well as hormone resistance. The aerial portions of these plants are similar to wild-type in appearance. Genetic analysis of these four mutants demonstrated that hormone resistance segregated as a recessive trait and that all four mutations were alleles of the auxin-resistant mutation aux1 [Maher HP, Martindale SJB (1980) Biochem Genet 18: 1041-1053]. These new mutants have been designated aux1-7, 1-12, 1-15, and 1-19. The sensitivity of wild-type and aux1-7 roots to indole-3-acetic acid, 2,4-dichlorophenoxyacetic acid, and ethylene was determined. The results of these assays show that aux1-7 plants require a 12-fold (indole-3-acetic acid) or 18-fold (2,4-dichlorophenoxyacetic acid) higher concentration of auxin than wild-type for a 50% inhibition of root growth. In addition, ethylene inhibition of root growth in aux1-7 plants is approximately 30% that of wild-type at saturating ethylene concentrations. These results indicate that aux1 plants are resistant to both auxin and ethylene. We have also determined the effect of ethylene treatment on chlorophyll loss and peroxidase activity in the leaves of aux1 and wild-type plants. No difference between mutant and wild-type plants was observed in these experiments, indicating that hormone resistance in aux1 plants may be limited to root growth. Our studies suggest that the AUX1 gene may have a specific function in the hormonal regulation of gravitropism.

Pickett, F. Bryan; Wilson, Allison K.; Estelle, Mark

1990-01-01

301

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

SciTech Connect

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.

Cole, R.D. (Illinois State Geological Survey, Champaign (United States))

1991-03-01

302

Genome-wide analysis of Aux\\/IAA and ARF gene families in Populus trichocarpa  

Microsoft Academic Search

BACKGROUND: Auxin\\/Indole-3-Acetic Acid (Aux\\/IAA) and Auxin Response Factor (ARF) transcription factors are key regulators of auxin responses in plants. We identified the suites of genes in the two gene families in Populus and performed comparative genomic analysis with Arabidopsis and rice. RESULTS: A total of 35 Aux\\/IAA and 39 ARF genes were identified in the Populus genome. Comparative phylogenetic analysis

Udaya C Kalluri; Stephen P DiFazio; Amy M Brunner; Gerald A Tuskan

2007-01-01

303

Adsorption of mixtures of nonionic sugar-based surfactants with other surfactants at solid\\/liquid interfaces  

Microsoft Academic Search

Sugar-based surfactants can be synthesized from renewable materials and are environmentally benign. They have some unique solution and interfacial properties and have potential applications in a wide variety of processes, and there is a need for corresponding information on their behavior at various interfaces. In this study, co-adsorption of nonionic sugar-based n-dodecyl-?-d-maltoside (DM) and anionic sodium dodecyl sulfate (SDS) on

Lei Zhang; P. Somasundaran

2006-01-01

304

Photopolymerization-induced crystallization in relation to solid-liquid phase diagrams of blends of poly(ethylene oxide)/multi-functional acrylate monomers  

NASA Astrophysics Data System (ADS)

The goal of the present dissertation is to elucidate of the phenomenon of photopolymerization-induced phase transition (PIPT) in order to provide guidance to the fabrication of polymer photonic crystals via photolithography. The phenomenon of photopolymerization-induced phase separation and crystallization is a phase transformation process driven by photochemical reaction, in which the phase ordering occurs during the photo patterning. Although the reaction-induced phase separation is well investigated, the photopolymerization-induced crystallization is new in this field. First, the solid-liquid phase diagrams of the starting blends of polyethylene oxide (PEO)/multi-functional acrylate monomers have been established by means of differential scanning calorimetry and optical microscope. It was found that the PEO/acrylate systems reveal various coexistence regions including isotropic (I), the coexistence of crystal + liquid (Cr 1+L2) and the crystal + crystal (Cr1+Cr2 ) gaps. A phase field theory pertaining to the solid-liquid phase transition in conjunction with the Flory Huggins theory for liquid-liquid phase separation has been developed to test with these experimental phase diagrams. The aforementioned coexistence regions have been further verified experimentally by probing the spatio-temporal emergence of crystalline structure and phase morphology using time-resolved optical microscopy following several temperature-quenches into these individual coexistence regions. The effects of molecular weight of PEO and acrylate arm topology of acrylate monomers on their blend phase diagrams have been explored. Guided by these established phase diagrams of the PEO/multi-functional acrylate blends, photopolymerization-induced crystallization experiments have been carried out at the isotropic temperatures slightly above the depressed melting points of PEO crystals corresponding to the liquidus line. The depressed melting curve shifts upward to the elevated temperatures and eventually surpasses the reaction temperature which in turn drives the system into the unstable gap triggering the photopolymerization-induced crystallization. Various crystalline phase morphologies including development of spherulites in the continuum of the isotropic region were observed in the crystal + liquid coexistence region. At higher reaction temperatures, above the melting temperature, viscous fingering (or fractal growth) takes place during photopolymerization, showing phase separated domains within these advancing viscous fingering structures. Finally, the study was extended to holographic photopolymerization that allows the reaction to occur predominantly in high intensity regions to create periodic patterns. Of particular interest is the growth of the hierarchical structures of PEO crystals and two-phase morphology within the stripes or interconnected channels and/or arrays of spheres.

Park, Soo Jeoung

305

Auxin-induced SCFTIR1Aux\\/IAA interaction involves stable modification of the SCFTIR1 complex  

Microsoft Academic Search

The plant hormone auxin can regulate gene expression by destabilizing members of the Aux\\/IAA family of transcriptional repressors. Auxin-induced Aux\\/IAA degradation requires the protein-ubiquitin ligase SCFTIR1, with auxin acting to enhance the interaction between the Aux\\/IAAs and SCFTIR1. SKP1, Cullin, and an F-box-containing protein (SCF)-mediated degradation is an important component of many eukaryotic signaling pathways. In all known cases to

Stefan Kepinski; Ottoline Leyser

2004-01-01

306

Viscous constitutive relations of solid-liquid composites in terms of grain boundary contiguity: 3. Causes and consequences of viscous anisotropy  

NASA Astrophysics Data System (ADS)

The viscous constitutive relations of partially molten rocks developed here show that an anisotropy in grain-scale melt distribution can lead to a strong anisotropy in the viscosity of the solid framework. With anisotropic viscosity, a direct coupling between shear and isotropic components of stress occurs, and hence, the role of shear deformation in melt migration significantly increases. We demonstrate the significant effects of viscous anisotropy on melt migration dynamics by solving the solid-liquid two-phase dynamics for two simple cases. First, in rotary shear deformation, an anisotropy creates a driving force for melt migration up stress gradients in the solid matrix, which does not exist with isotropic viscosity. Second, in uniform simple shear deformation, melt segregates spontaneously into low-angle bands due to anisotropic melt alignment, in close agreement with experimental observations. Our results indicate that stress-induced melt alignment at the grain scale drives further melt redistribution over distances much longer than the grain scale. The development of such "multiscale anisotropy" is demonstrated by "forward" or ab initio approaches based on the equations of two-phase dynamics, in which the viscous constitutive relation is based on observed microstructure and realistic rheology. When applied to a simple approximation of flow in the mantle beneath ridge and subduction zone, the anisotropic constitutive relation significantly affects melt migration patterns.

Takei, Yasuko; Holtzman, Benjamin K.

2009-06-01

307

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

USGS Publications Warehouse

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.

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

1992-01-01

308

2D analogues of the inverted hexagonal phase self-assembled from 4,6-dialkoxylated isophthalic acids at solid-liquid interfaces  

NASA Astrophysics Data System (ADS)

Self-assembly of organic molecules at solid-liquid interfaces is a route for developing novel functional materials on surfaces and modeling assembly phenomena in 3D. 5-Alkoxylated isophthalic acids (ISA) are known to self-assemble into two-dimensional (2D) lamellae at the interface between a surface of Au(111) or HOPG (highly oriented pyrolytic graphite) and a solvent. Presently, the self-assembly of 4,6-dialkoxylated isophthalic acid derivatives with variable alkyl chain length is investigated at Au(111)-water, Au(111)-tetradecane and HOPG-tetradecane interfaces with a particular focus on the first one. The main aspect of this study is to evaluate the role of the molecular geometry and different interactions in the 2D assembly of amphiphilic molecules. In contrast to 5-alkoxylated ISA, 4,6-dialkoxylated ISA derivatives self-assemble preferentially into arrays of cyclic pentameric/hexameric structures, which appear as 2D analogues of the inverted hexagonal phase of lipids. As a general trend, the derivatives bearing shorter alkyl chains show a higher level of ordering at Au(111)-liquid interfaces. In particular, at the Au(111)-water interface, the 4,6-diheptyloxy ISA derivative forms exclusively pentamers, which are arranged in a quasi-hexagonal lattice. Moreover, the cyclic pentameric features are not empty but host a single isophthalic acid residue which is found to be dynamic. Finally, the packing of the diheptyloxy derivative shows a distinct potential dependence: while at more negative potentials the pentameric arrangement is converted into lamellae, at more positive potentials a loosely packed zig-zag pattern is formed. The present results show that at different solid-liquid interfaces 4,6-dialkoxylated ISA derivatives tend to form cyclic structures that are 2D analogues of an inverted hexagonal phase, akin to lipids having two hydrophobic alkyl chains and a small polar head group. Moreover, the substrate potential at the Au(111)-water interface can tune the 2D molecular arrangement.Self-assembly of organic molecules at solid-liquid interfaces is a route for developing novel functional materials on surfaces and modeling assembly phenomena in 3D. 5-Alkoxylated isophthalic acids (ISA) are known to self-assemble into two-dimensional (2D) lamellae at the interface between a surface of Au(111) or HOPG (highly oriented pyrolytic graphite) and a solvent. Presently, the self-assembly of 4,6-dialkoxylated isophthalic acid derivatives with variable alkyl chain length is investigated at Au(111)-water, Au(111)-tetradecane and HOPG-tetradecane interfaces with a particular focus on the first one. The main aspect of this study is to evaluate the role of the molecular geometry and different interactions in the 2D assembly of amphiphilic molecules. In contrast to 5-alkoxylated ISA, 4,6-dialkoxylated ISA derivatives self-assemble preferentially into arrays of cyclic pentameric/hexameric structures, which appear as 2D analogues of the inverted hexagonal phase of lipids. As a general trend, the derivatives bearing shorter alkyl chains show a higher level of ordering at Au(111)-liquid interfaces. In particular, at the Au(111)-water interface, the 4,6-diheptyloxy ISA derivative forms exclusively pentamers, which are arranged in a quasi-hexagonal lattice. Moreover, the cyclic pentameric features are not empty but host a single isophthalic acid residue which is found to be dynamic. Finally, the packing of the diheptyloxy derivative shows a distinct potential dependence: while at more negative potentials the pentameric arrangement is converted into lamellae, at more positive potentials a loosely packed zig-zag pattern is formed. The present results show that at different solid-liquid interfaces 4,6-dialkoxylated ISA derivatives tend to form cyclic structures that are 2D analogues of an inverted hexagonal phase, akin to lipids having two hydrophobic alkyl chains and a small polar head group. Moreover, the substrate potential at the Au(111)-water interface can tune the 2D molecular arrangement. Electronic supplementary information (ESI) avai

Klymchenko, Andrey S.; Furukawa, Shuhei; Balandina, Tanya; Müllen, Klaus; van der Auweraer, Mark; de Feyter, Steven

2010-09-01

309

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)

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.

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

1999-01-01

310

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

PubMed

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

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

2002-01-01

311

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

SciTech Connect

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.

Hoffer, Saskia

2002-08-19

312

Réactions aux interfaces de bicristaux compatibles et incompatibles  

NASA Astrophysics Data System (ADS)

La rupture intergranulaire peut apparaître suite à la non accommodation des contraintes au voisinage de l'interface. La transmission du glissement au travers d'une interface est un des modes de relaxation possible qui dépend des paramètres suivants : facteurs géométriques (caractéristiques de l'interface et systèmes de glissement activés), constantes élastiques de chacune des phases. Dans cette étude, la microscopie électronique à transmission (MET) est utilisée pour analyser les configurations de dislocations résultant d'une déformation par fatigue de bicristaux d'acier austénoferritique de désorientations contrôlées. Deux types de bicristaux sont étudiés, compatible et incompatible plastiquement. Pour chacun d'eux, la déformation est initiée soit dans la phase ferritique ? soit dans la phase austénitique ? selon la localisation d'une entaille préalable à l'essai mécanique. Les résultats permettent de remonter aux mécanismes élémentaires qui régissent le transfert “direct” ou “indirect” des dislocations à travers l'interface. Une corrélation avec le comportement des bicristaux à l'échelle macroscopique est également tentée.

Taisne, A.; Décamps, B.; Priester, L.

2003-03-01

313

Tuning the packing density of 2D supramolecular self-assemblies at the solid-liquid interface using variable temperature.  

PubMed

The two-dimensional (2D) crystal engineering of molecular architectures on surfaces requires controlling various parameters related respectively to the substrate, the chemical structure of the molecules, and the environmental conditions. We investigate here the influence of temperature on the self-assembly of hexakis(n-dodecyl)-peri-hexabenzocoronene (HBC-C(12)) adsorbed on gold using scanning tunneling microscopy (STM) at the liquid/solid interface. We show that the packing density of 2D self-assembled HBC-C(12) can be precisely tuned by adjusting the substrate temperature. Increasing the temperature progressively over the 20-50 degrees C range induces three irreversible phase transitions and a 3-fold increase of the packing density from 0.111 to 0.356 molecule/nm(2). High-resolution STM images reveal that this 2D packing density increase arises from the stepwise desorption of the n-dodecyl chains from the gold surface. Such temperature-controlled irreversible phase transitions are thus a versatile tool that can then be used to adjust the packing density of highly ordered functional materials in view of applications in organic electronic devices. PMID:20155970

Marie, Camille; Silly, Fabien; Tortech, Ludovic; Müllen, Klaus; Fichou, Denis

2010-03-23

314

Solid-Liquid Equilibria of Benzoic Acid Derivatives in 1Octanol * * Supported by the National Natural Science Foundation of China (No.20676101) and the Natural Science Foundation of Tianjin University of Science & Technology (No.20050207)  

Microsoft Academic Search

The solid-liquid equilibrium of benzoic acid derivatives in 1-octanol was first determined in this article. Using a laser monitoring observation technique, the solubility data of 0-amino-benzoic acid, p-amino-benzoic acid, 0-chloro-benzoic acid, and m-nitro-benzoic acid in 1-octanol were measured by the polythermal method in the temperature range of 20–50°C. The experimental data were regressed with the Wilson equation and the ?H

Qingzhu JIA; Peisheng MA; Shaona MA; Chang WANG

2007-01-01

315

Overview of applications of Laser-Induced Breakdown Spectroscopy (LIBS)  

SciTech Connect

Laser-induced breakdown spectroscopy (LIBS) is a method of performing elemental analyses of solids, liquids, and gases using the microplasma produced by a focused laser pulse. Because the microplasma is formed by optical radiation, LIBS has some important advantages compared to conventional laboratory based analytical methods. Three applications are discussed which use the LIBS method. 6 refs., 8 figs., 2 tabs.

Cremers, D.A.

1987-01-01

316

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

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 ?g kg(-1)), limits of quantification (LOQs) (from 0.06 to 0.8 ?g 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 ?g kg(-1). At least two different mycotoxins were co-occurred in three samples, and three AFs were simultaneously detected in one sample. PMID:23486692

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

2013-05-01

317

Hybrid field-assisted solid-liquid-solid dispersive extraction for the determination of organochlorine pesticides in tobacco with gas chromatography.  

PubMed

A novel one-step sample preparation technique termed hybrid field-assisted solid-liquid-solid dispersive extraction (HF-SLSDE) was developed in this study. A simple glass system equipped with a condenser was designed as an extraction vessel. The HF-SLSDE technique was a three-phase dispersive extraction approach. Target analytes were extracted from the sample into the extraction solvent enhanced by the hybrid field. Meanwhile, the interfering components were adsorbed by dispersing sorbent. No cleanup step preceded chromatographic analysis. The efficiency of the HF-SLSDE approach was demonstrated in the determination of organochlorine pesticide (OCP) residues in tobacco with a gas chromatography-electron capture detector (GC-ECD). Various operation conditions were studied systematically. Low detection limits (0.3-1.6 ?g/kg) and low quantification limits (1.0-4.5 ?g/kg) were achieved under the optimized conditions. The recoveries of OCPs ranged from 70.2% to 118.2%, with relative standard deviations of <9.6%, except for the lowest fortification level. Because of the effect of the hybrid field, HF-SLSDE showed significant predominance compared with other extraction techniques. The dispersing sorbent with good cleanup ability used in this study was also found to be a microwave absorption medium, which could heat the nonpolar extraction solvent under microwave irradiation. Different microstructures of tobacco samples before and after extractions demonstrated the mechanism of HF-SLSDE was based on an explosion at the cell level. According to the results, HF-SLSDE was proved to be a simple and effective sample preparation method for the analysis of pesticide residues in solid samples and could potentially be extended to other nonpolar target analytes in a complex matrix. PMID:22092268

Zhou, Ting; Xiao, Xiaohua; Li, Gongke

2012-01-01

318

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

NASA Astrophysics Data System (ADS)

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.

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

2013-02-01

319

Structural characterization of the phospholipid stabilizer layer at the solid-liquid interface of dispersed triglyceride nanocrystals with small-angle x-ray and neutron scattering.  

PubMed

Dispersions of crystalline nanoparticles with at least one sufficiently large unit cell dimension can give rise to Bragg reflections in the small-angle scattering range. If the nanocrystals possess only a small number of unit cells along these particular crystallographic directions, the corresponding Bragg reflections will be broadened. In a previous study of phospholipid stabilized dispersions of ?-tripalmitin platelets [Unruh, J. Appl. Crystallogr. 40, 1008 (2007)], the x-ray powder pattern simulation analysis (XPPSA) was developed. The XPPSA method facilitates the interpretation of the rather complicated small-angle x-ray scattering (SAXS) curves of such dispersions of nanocrystals. The XPPSA method yields the distribution function of the platelet thicknesses and facilitates a structural characterization of the phospholipid stabilizer layer at the solid-liquid interface between the nanocrystals and the dispersion medium from the shape of the broadened 001 Bragg reflection. In this contribution an improved and extended version of the XPPSA method is presented. The SAXS and small-angle neutron scattering patterns of dilute phospholipid stabilized tripalmitin dispersions can be reproduced on the basis of a consistent simulation model for the particles and their phospholipid stabilizer layer on an absolute scale. The results indicate a surprisingly flat arrangement of the phospholipid molecules in the stabilizer layer with a total thickness of only 12 Å. The stabilizer layer can be modeled by an inner shell for the fatty acid chains and an outer shell including the head groups and additional water. The experiments support a dense packing of the phospholipid molecules on the nanocrystal surfaces rather than isolated phospholipid domains. PMID:23848684

Schmiele, Martin; Schindler, Torben; Unruh, Tobias; Busch, Sebastian; Morhenn, Humphrey; Westermann, Martin; Steiniger, Frank; Radulescu, Aurel; Lindner, Peter; Schweins, Ralf; Boesecke, Peter

2013-06-01

320

Evidence supporting an intentional Neandertal burial at La Chapelle-aux-Saints  

PubMed Central

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.

Rendu, William; Beauval, Cedric; Crevecoeur, Isabelle; Bayle, Priscilla; Balzeau, Antoine; Bismuth, Thierry; Bourguignon, Laurence; Delfour, Geraldine; Faivre, Jean-Philippe; Lacrampe-Cuyaubere, Francois; Tavormina, Carlotta; Todisco, Dominique; Turq, Alain; Maureille, Bruno

2014-01-01

321

Evidence supporting an intentional Neandertal burial at La Chapelle-aux-Saints.  

PubMed

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

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

322

Application of the constrained fluid ?-integration path to the calculation of high temperature Au(110) surface free energies  

Microsoft Academic Search

Recently a method termed constrained fluid ?-integration was proposed for calculating the free energy difference between bulk solid and liquid reference states via the construction of a reversible thermodynamic integration path; coupling the two states in question. The present work shows how the application of the constrained fluid ?-integration concept to solid\\/liquid slab simulation cells makes possible a generally applicable

Gregory Grochola; Ian K. Snook; Salvy P. Russo

2005-01-01

323

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

PubMed

In an earlier phase of this study, we compared the performances of pilot scale treatment systems operated in either a conventional enhanced biological phosphorus removal (CEBPR) mode, or a membrane enhanced biological phosphorus removal (MEBPR) mode. In the present investigation, we characterized the bacterial community populations in these processes during parallel operation with the same municipal wastewater feed. The objectives of the study were (1) to assess the similarity of the bacterial communities supported in the two systems over time, (2) to determine if distinct bacterial populations are associated with the MEBPR and CEBPR processes, and (3) to relate the dynamics of the community composition to changes in treatment process configuration and to treatment process performance. The characteristics of the bacterial populations were first investigated with ribosomal intergenic spacer analysis, or RISA. To further understand the bacterial population dynamics, important RISA phylotypes were isolated and identified through 16S RNA gene sequencing. The parallel MEBPR and CEBPR systems developed bacterial communities that were distinct. The CEBPR community appeared to exhibit greater diversity, and this may have been the primary reason why the CEBPR treatment train demonstrated superior functional stability relative to the MEBPR counterpart. Moreover, the more diverse bacterial population apparent in the CEBPR system was observed to be more dynamic than that of the MEBPR process. Several RISA bands were found to be characteristic of either the membrane or conventional biological system. In particular, the MEBPR configuration appeared to be selective for the slow-growing organism Magnospira bakii and for the foam-associated Microthrix parvicella and Gordonia sp., while gravity separation led to the washout of M. parvicella. In both pilot trains, sequence analysis confirmed the presence of EBPR-related organisms such as Accumulibacter phosphatis. The survey of the 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

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

2010-05-01

324

Auxin-induced SCFTIR1-Aux/IAA interaction involves stable modification of the SCFTIR1 complex.  

PubMed

The plant hormone auxin can regulate gene expression by destabilizing members of the Aux/IAA family of transcriptional repressors. Auxin-induced Aux/IAA degradation requires the protein-ubiquitin ligase SCF(TIR1), with auxin acting to enhance the interaction between the Aux/IAAs and SCF(TIR1). SKP1, Cullin, and an F-box-containing protein (SCF)-mediated degradation is an important component of many eukaryotic signaling pathways. In all known cases to date, the interaction between the targets and their cognate SCFs is regulated by signal-induced modification of the target. The mechanism by which auxin promotes the interaction between SCF(TIR1) and Aux/IAAs is not understood, but current hypotheses propose auxin-induced phosphorylation, hydroxylation, or proline isomerization of the Aux/IAAs. We found no evidence to support these hypotheses or indeed that auxin induces any stable modification of Aux/IAAs to increase their affinity for SCF(TIR1). Instead, we present data suggesting that auxin promotes the SCF(TIR1)-Aux/IAA interaction by affecting the SCF component, TIR1, or proteins tightly associated with it. PMID:15295098

Kepinski, Stefan; Leyser, Ottoline

2004-08-17

325

Identification and Analyses of AUX-IAA target genes controlling multiple pathways in developing fiber cells of Gossypium hirsutum L  

PubMed Central

Technological development led to an increased interest in systems biological approaches in plants to characterize developmental mechanism and candidate genes relevant to specific tissue or cell morphology. AUX-IAA proteins are important plant-specific putative transcription factors. There are several reports on physiological response of this family in Arabidopsis but in cotton fiber the transcriptional network through which AUX-IAA regulated its target genes is still unknown. in-silico modelling of cotton fiber development specific gene expression data (108 microarrays and 22,737 genes) using Algorithm for the Reconstruction of Accurate Cellular Networks (ARACNe) reveals 3690 putative AUX-IAA target genes of which 139 genes were known to be AUX-IAA co-regulated within Arabidopsis. Further AUX-IAA targeted gene regulatory network (GRN) had substantial impact on the transcriptional dynamics of cotton fiber, as showed by, altered TF networks, and Gene Ontology (GO) biological processes and metabolic pathway associated with its target genes. Analysis of the AUX-IAA-correlated gene network reveals multiple functions for AUX-IAA target genes such as unidimensional cell growth, cellular nitrogen compound metabolic process, nucleosome organization, DNA-protein complex and process related to cell wall. These candidate networks/pathways have a variety of profound impacts on such cellular functions as stress response, cell proliferation, and cell differentiation. While these functions are fairly broad, their underlying TF networks may provide a global view of AUX-IAA regulated gene expression and a GRN that guides future studies in understanding role of AUX-IAA box protein and its targets regulating fiber development.

Nigam, Deepti; Sawant, Samir V

2013-01-01

326

Degradation of Aux/IAA proteins is essential for normal auxin signalling.  

PubMed

The growth substance auxin mediates many cellular processes, including division, elongation and differentiation. PSIAA6 is a member of the Aux/IAA family of short-lived putative transcriptional regulators that share four conserved domains and whose mRNAs are rapidly induced in the presence of auxin. Here PSIAA6 was shown to serve as a dominant transferable degradation signal when present as a translational fusion with firefly luciferase (LUC), with an in vivo half-life of 13.5 min in transgenic Arabidopsis seedlings. In a transient assay system in tobacco protoplasts using steady-state differences as an indirect measure of protein half-life, LUC fusions with full-length PSIAA6 and IAA1, an Aux/IAA protein from Arabidopsis, resulted in protein accumulations that were 3.5 and 1. 0%, respectively, of that with LUC alone. An N-terminal region spanning conserved domain II of PSIAA6 containing amino acids 18-73 was shown to contain the necessary cis-acting element to confer low protein accumulation onto LUC, while a fusion protein with PSIAA6 amino acids 71-179 had only a slight effect. Single amino acid substitutions of PSIAA6 in conserved domain II, equivalent to those found in two alleles of axr3, a gene that encodes Aux/IAA protein IAA17, resulted in a greater than 50-fold increase in protein accumulation. Thus, the same mutations resulting in an altered auxin response phenotype increase Aux/IAA protein accumulation, providing a direct link between these two processes. In support of this model, transgenic plants engineered to over-express IAA17 have an axr3-like phenotype. Together, these data suggest that rapid degradation of Aux/IAA proteins is necessary for a normal auxin response. PMID:10758506

Worley, C K; Zenser, N; Ramos, J; Rouse, D; Leyser, O; Theologis, A; Callis, J

2000-03-01

327

Moduler les cotisations employeurs à l’assurance chômage : les expériences de bonus-malus aux Etats-Unis  

Microsoft Academic Search

[fre] Notre article présente les résultats des études consacrées aux effets du système américain de modulation des cotisations patronales à l'assurance-chômage (experience rating) et quelques réflexions sur le cas de la France. Aux Etats-Unis, ces cotisations dépendent du nombre des licenciements effectués par l'entreprise au cours des années les plus récentes. Nous commençons par un rappel succinct de l'évolution historique

David Margolis

2000-01-01

328

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

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 ?max = 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 ?g/L (r(2) = 0.991) and 0.21 ?g/L as the limit of detection. PMID:24890459

Sehati, Negar; Dalali, Nasser; Soltanpour, Shahla; Seyed Dorraji, Mir Saeed

2014-08-01

329

Genome-wide identification, functional analysis and expression profiling of the Aux/IAA gene family in tomato.  

PubMed

Auxin is a central hormone that exerts pleiotropic effects on plant growth including the development of roots, shoots, flowers and fruit. The perception and signaling of the plant hormone auxin rely on the cooperative action of several components, among which auxin/indole-3-acetic acid (Aux/IAA) proteins play a pivotal role. In this study, we identified and comprehensively analyzed the entire Aux/IAA gene family in tomato (Solanum lycopersicum), a reference species for Solanaceae plants, and the model plant for fleshy fruit development. Functional characterization using a dedicated single cell system revealed that tomato Aux/IAA proteins function as active repressors of auxin-dependent gene transcription, with, however, different Aux/IAA members displaying varying levels of repression. Phylogenetic analysis indicated that the Aux/IAA gene family is slightly contracted in tomato compared with Arabidopsis, with a lower representation of non-canonical proteins. Sl-IAA genes display distinctive expression pattern in different tomato organs and tissues, and some of them display differential responses to auxin and ethylene, suggesting that Aux/IAAs may play a role in linking both hormone signaling pathways. The data presented here shed more light on Sl-IAA genes and provides new leads towards the elucidation of their function during plant development and in mediating hormone cross-talk. PMID:22368074

Audran-Delalande, Corinne; Bassa, Carole; Mila, Isabelle; Regad, Farid; Zouine, Mohamed; Bouzayen, Mondher

2012-04-01

330

A combinatorial TIR1/AFB-Aux/IAA co-receptor system for differential sensing of auxin  

PubMed Central

The plant hormone auxin regulates virtually every aspect of plant growth and development. Auxin acts by binding to the F-box protein TIR1 and promotes the degradation of the Aux/IAA transcriptional repressors. Here, we show that efficient auxin binding requires assembly of an auxin co-receptor complex consisting of TIR1 and an Aux/IAA protein. Heterologous experiments in yeast and quantitative IAA binding assays using purified proteins showed that different combinations of TIR1 and Aux/IAA proteins form co-receptor complexes with a wide range of auxin-binding affinities. Auxin affinity appears to be largely determined by the Aux/IAA. As there are 6 TIR1/AFBs and 29 Aux/IAA proteins in Arabidopsis thaliana, combinatorial interactions may result in many co-receptors with distinct auxin sensing properties. We also demonstrate that the AFB5-Aux/IAA co-receptor selectively binds the auxinic herbicide picloram. This co-receptor system broadens the effective concentration range of the hormone and may contribute to the complexity of auxin response.

Villalobos, Luz Irina A. Calderon; Lee, Sarah; De Oliveira, Cesar; Ivetac, Anthony; Brandt, Wolfgang; Armitage, Lynne; Sheard, Laura B.; Tan, Xu; Parry, Geraint; Mao, Haibin; Zheng, Ning; Napier, Richard; Kepinski, Stefan; Estelle, Mark

2012-01-01

331

Genome-wide analysis of Aux/IAA and ARF gene families in Populus trichocarpa  

SciTech Connect

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.

Kalluri, Udaya C [ORNL; DiFazio, Stephen P [West Virginia University; Brunner, A. [Virginia Polytechnic Institute and State University (Virginia Tech); Tuskan, Gerald A [ORNL

2007-01-01

332

INVESTISSEMENTS FRANÇAIS AUX ETATS-UNIS, STRATÉGIES DE CROISSANCE EXTERNE ET RÉACTIONS DU MARCHÉ BOURSIER  

Microsoft Academic Search

Résumé : l'objectif de cet article est d'évaluer la réaction des marchés boursiers suite à l'annonce d'investissements directs par des entreprises françaises aux Etats-Unis. L'étude empirique se fonde sur une méthodologie d'étude d'événements, destinée à mesurer les rendements anormaux moyens et les rendements anormaux moyens cumulés, sur les cotations à la Bourse de Paris, associés à l'annonce d'acquisitions de firmes

Pierre-Xavier MESCHI; Emmanuel METAIS

333

Decommissioning of the Nuclear Licensed Facilities at the Fontenay aux Roses CEA Center  

SciTech Connect

This is a summary of the program for the decommissioning of all the CEA's facilities in Fontenay aux Roses. The particularity of this center is that it is located in a built-up area. Taking into account the particularities of the various buildings and the levels of radioactivity in them, it was possible to devise a coherent, optimized program for the CEA-FAR licensed nuclear facility decommissioning operations.

Jeanjacques, Michel; Piketty, Laurence; Mandard, Lionel; Pedron, Guy; Boissonneau, Jean Francois; Fouquereau, Alain; Pichereau, Eric; Lethuaire, Nathalie; Estivie, David; Binet, Cedric; Meden, Igor [Commissariat a l'Energie Atomique, Direction de l'Energie Nucleaire, Direction deleguee des Activites Nucleaires de Saclay, Departement des Reacteurs et des Services Nucleaires, Service d'Assainissement de Fontenay Aux Roses : 18, route du Panorama, BP6, 92265 Fontenay aux Roses Cedex (France)

2008-01-15

334

Auxin-responsive grape Aux/IAA9 regulates transgenic Arabidopsis plant growth.  

PubMed

We report the characterization of VvIAA9, an auxin/indole-3-acetic acid (Aux/IAA) protein, in grapevine (Vitis vinifera L.). VvIAA9 was expressed abundantly in leaves and berries. VvIAA9 transcription was drastically upregulated from anthesis to onset of ripening (termed véraison), in which berry diameter rapidly increased. Treatment with exogenous IAA induced VvIAA9 expression in grape leaves, suggesting that VvIAA9 is an auxin-responsive Aux/IAA protein. The overexpression of VvIAA9 in Arabidopsis thaliana promoted plant growth, including rapid floral transition. However, no morphological differences were observed between the control plant and the VvIAA9-overexpressing plant. The overexpression of VvIAA9 in Arabidopsis plants rendered the plants hyposensitive to exogenous IAA. The exogenous IAA treatment did not induce VvIAA9-overexpressing Arabidopsis plant growth and expression of IAA-responsive HAT2. Taken together, we conclude that grape Aux/IAA9 protein is likely to play a crucial role as a plant growth regulator. PMID:22535320

Fujita, Keiko; Horiuchi, Haruka; Takato, Haruka; Kohno, Minako; Suzuki, Shunji

2012-07-01

335

Electronic and geometric structure of AuxCuy clusters studied by density functional theory  

NASA Astrophysics Data System (ADS)

We have determined the stable structures of AuCun, Au2Cun, Au3Cun and AuxCu8-x clusters. It has been observed that AuCun, Au2Cun and Au3Cun systems have two-dimensional (2D) structures up to six atoms and they become three-dimensional (3D) afterwards. AuxCu8-x clusters favor 3D structures till the Au7Cu1 cluster. We have found a lowest energy isomer of Au6Cu2 from the literature. Bond lengths, binding energies, density of states (DOS), highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) gaps, ionization potential (IP) and electron affinity (EA) have been calculated for these structures using the first principles density functional theory (DFT) within the generalized gradient approximation (GGA) and the local density approximation (LDA). Generally, we have observed the overlap between s electrons of Cu and p electrons of Au near the Fermi level. Charge transfers are calculated by using the Löwdin analysis. It is observed that one Cu atom does not significantly modify the clusters which have more gold atoms. It is also seen that these clusters generally have nonmagnetic properties and results are consistent with the hybridization between s and d orbitals of Au in AuxCu8-x clusters.

Kadioglu, Y.; Üzengi Aktürk, O.; Tomak, M.

2014-01-01

336

L'Earned Income Tax Credit, un crédit d'impôt ciblé sur les foyers de salariés modestes aux États-Unis  

Microsoft Academic Search

[fre] L’Earned Income Tax Credit (EITC) est un crédit d’impôt bénéficiant aux foyers dans lesquels au moins une personne travaille. Les hausses de barème au cours de la décennie 90 en ont fait un mécanisme substantiel de soutien aux revenus des familles aux États-Unis. En 1998, ce mécanisme concerne 19,5 millions de foyers, pour un coût d’environ 30 milliards de

Olivier Bontout

2000-01-01

337

Vaincre la r?ticence ? l'instauration d'un nouveau sch?ma ? base d'enfuvirtide gr?ce aux soins aux patients et aux mesures de soutien  

PubMed Central

Les patients peuvent être réticents à l’idée de commencer un traitement par l’enfuvirtide en raison de préoccupations relatives à l’auto-injection et à d’autres questions connexes. Étant donné que l’introduction d’une nouvelle classe de médicaments peut améliorer considérablement l’efficacité d’un schéma antirétroviral, appuyer le patient dans l’instauration de l’enfuvirtide, un agent sûr et efficace appartenant à une nouvelle classe, offre des bienfaits thérapeutiques. Dans le cas du présent patient, qui affichait une résistance aux trois grandes classes d’antirétroviraux, l’enfuvirtide a été ajouté avec succès au traitement grâce à un groupe d’aide par les pairs et à une assistance clinique. L’acceptation du patient a augmenté grâce à l’utilisation d’un système d’injection sans aiguilles (Biojector), avec des effets secondaires minimes et une amélioration significative du contrôle virologique et immunologique.

Trottier, Benoit

2007-01-01

338

Structural characterization of the voltage sensor domain and voltage-gated K+- channel proteins vectorially-oriented within a single bilayer membrane at the solid/vapor and solid/liquid interfaces via neutron interferometry  

PubMed Central

The voltage-sensor domain (VSD) is a modular 4-helix bundle component that confers voltage sensitivity to voltage-gated cation channels in biological membranes. Despite extensive biophysical studies and the recent availability of x-ray crystal structures for a few voltage-gated potassium (Kv-) channels and a voltage-gate sodium (Nav-) channel, a complete understanding of the cooperative mechanism of electromechanical coupling, interconverting the closed-to-open states (i.e. non-conducting to cation conducting) remains undetermined. Moreover, the function of these domains is highly dependent on the physical-chemical properties of the surrounding lipid membrane environment. The basis for this work was provided by a recent structural study of the VSD from a prokaryotic Kv-channel vectorially-oriented within a single phospholipid (POPC; 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine) membrane investigated by x-ray interferometry at the solid/moist He (or solid/vapor) and solid/liquid interfaces thus achieving partial to full hydration, respectively (Gupta et. al. Phys. Rev E. 2011, 84). Here, we utilize neutron interferometry to characterize this system in substantially greater structural detail at the sub-molecular level, due to its inherent advantages arising from solvent contrast variation coupled with the deuteration of selected sub-molecular membrane components, especially important for the membrane at the solid/liquid interface. We demonstrate the unique vectorial orientation of the VSD and the retention of its molecular conformation manifest in the asymmetric profile structure of the protein within the profile structure of this single bilayer membrane system. We definitively characterize the asymmetric phospholipid bilayer solvating the lateral surfaces of the VSD protein within the membrane. The profile structures of both the VSD protein and phospholipid bilayer depend upon the hydration state of the membrane. We also determine the distribution of water and exchangeable hydrogen throughout the profile structure of both the VSD itself and the VSD:POPC membrane. These two experimentally-determined water and exchangeable hydrogen distribution profiles are in good agreement with molecular dynamics simulations of the VSD protein vectorially-oriented within a fully hydrated POPC bilayer membrane, supporting the existence of the VSD’s water pore. This approach was extended to the full-length Kv-channel (KvAP) at solid/liquid interface, providing the separate profile structures of the KvAP protein and the POPC bilayer within the reconstituted KvAP:POPC membrane.

Gupta, S.; Dura, J.A.; Freites, J.A.; Tobias, D.J.; Blasie, J. K.

2012-01-01

339

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)

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 ( ?max). 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 ?g 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 ?g L -1. All experiments were carried out at room temperature (25 ± 0.5 °C).

Es'haghi, Zarrin; Khooni, Maliheh Ahmadi-Kalateh; Heidari, Tahereh

2011-08-01

340

Aux1p/Swa2p Is Required for Cortical Endoplasmic Reticulum Inheritance in Saccharomyces cerevisiae  

PubMed Central

In the yeast Saccharomyces cerevisiae, the endoplasmic reticulum (ER) is found at the periphery of the cell and around the nucleus. The segregation of ER through the mother-bud neck may occur by more than one mechanism because perinuclear, but not peripheral ER, requires microtubules for this event. To identify genes whose products are required for cortical ER inheritance, we have used a Tn3-based transposon library to mutagenize cells expressing a green fluorescent protein-tagged ER marker protein (Hmg1p). This approach has revealed that AUX1/SWA2 plays a role in ER inheritance. The COOH terminus of Aux1p/Swa2p contains a J-domain that is highly related to the J-domain of auxilin, which stimulates the uncoating of clathrin-coated vesicles. Deletion of the J-domain of Aux1p/Swa2p leads to vacuole fragmentation and membrane accumulation but does not affect the migration of peripheral ER into daughter cells. These findings suggest that Aux1p/Swa2p may be a bifunctional protein with roles in membrane traffic and cortical ER inheritance. In support of this hypothesis, we find that Aux1p/Swa2p localizes to ER membranes.

Du, Yunrui; Pypaert, Marc; Novick, Peter; Ferro-Novick, Susan

2001-01-01

341

Soins primaires aux adultes ayant une d?ficience d?veloppementale  

PubMed Central

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 nature éthique des soins. Les lignes directrices sont formulées dans le contexte d’un cadre éthique qui tient compte des questions comme le consentement éclairé et l’évaluation des bienfaits pour la santé par rapport aux risques de préjudice. Conclusion La mise en œuvre des lignes directrices proposées ici améliorerait la santé des adultes ayant une DD et minimiserait les disparités sur les plans de la santé et des soins de santé entre les adultes ayant une DD et la population en général.

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

342

Study of electronic properties in RCuAuxAl3 compounds, where R=Ce, La  

NASA Astrophysics Data System (ADS)

The magnetization, specific heat, electrical resistivity and magnetoresistance were measured on CeCuAuxAl3 compounds. The increase of structure parameters with substitution of Cu by larger atoms of Au was observed. Such a substitution causes a decrease of the Néel temperature as well as the Kondo temperature. The strong ferromagnetic correlations were found in the series, at least in the gold rich compounds. Nevertheless, all the compounds order antiferromagneticaly and no further phase transition was observed. The La counterparts were investigated by means of electrical resistivity and their basic physical properties are presented as well.

Klicpera, M.; Javorský, P.

2014-08-01

343

Identification and expression analysis of primary auxin-responsive Aux/IAA gene family in cucumber (Cucumis sativus).  

PubMed

Aux/IAA is an important gene family involved in many aspects of growth and development. Aux/IAA proteins are short-lived nuclear proteins that are induced primarily by various phytohormones. In this study, 29 Aux/IAA family genes (CsIAA01-CsIAA29) were identified and characterized in cucumber, including gene structures, phylogenetic relationships, conserved protein motifs and chromosomal locations. These genes show distinct organizational patterns of their putative motifs. The distributions of the genes vary: except for five CsIAA genes in cucumber that were not located, seven CsIAA genes were found on scaffold, while the other 17 CsIAA genes were distributed on seven other chromosomes. Based on a phylogenetic analysis of the Aux/IAA protein sequences from cucumber, Arabidopsis and other plants, the Aux/IAA genes in cucumber were categorized into seven subfamilies. To investigate whether the expression of CsIAA genes is associated with auxin induction, their transcript levels were monitored in seedlings treated with IAA (indole-3-acetic acid), and their expression patterns were analysed by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR). The results showed that 11/29 CsIAA genes were expressed in leaves whether treated with IAA or not and the time course of processing and compared with the control, five CsIAA genes showed low expression only after 60 min treatment with IAA, while 11 genes showed no expression. These results provide useful information for further functional analysis of Aux/IAA gene family in cucumber. PMID:24371172

Gan, Defang; Zhuang, Dan; Ding, Fei; Yu, Zhenzhou; Zhao, Yang

2013-12-01

344

Loi constitutive chimioplastique pour le beton expose aux hautes temperatures  

NASA Astrophysics Data System (ADS)

Concrete is the most widely used construction material in the world. Even though it has been used for several centuries, its behavior to high temperature remains to be understood. In the light of recent extreme events, including accidents, and arson, special attention has been focused on the performance of concrete in the fire safety assessment of buildings and tunnels. Fire represents one of the most severe conditions encountered during the life-time of a structure. Concrete exposed to high temperature can significantly jeopardize the structural integrity and load bearing capacity of the structure. Spalling of concrete remains one of the main issues to be addressed in the case of fire in buildings and tunnels. Successful modeling of this phenomenon depends not only on the accurate prediction of the temperature distribution through structural concrete but also on its mechanical response to the heating and boundaries restrains conditions and the migration of moisture and associated pore pressures. Therefore, it is necessary to develop a reliable formulation of concrete with all required information to understand its behavior during and after exposure to elevated temperature. It is also necessary to properly assess the effects of thermal degradation in order to develop predictive tools and validate design codes. Many structural problems can be adequately worthy by an elastoplastic model. The ultimate goal of this study is the development of a new constitutive model under a chemoplastic framework. To do this, an experimental program is carried out. The purpose of this program is twofold. First, it is essential to calibrate the proposed constitutive law that will be developed, and, second, for defining an inverse a problem. Usually, uniaxial and triaxial tests, conducted with confining pressure varied between 1.3 and 24 MPa and a temperature up to 700°C, allow us to identify the constitutive law parameters. This law reproduces the reduced field strength due to 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.

Hammoud, Rabah

345

The AUX1 LAX family of auxin influx carriers is required for the establishment of embryonic root cell organization in Arabidopsis thaliana  

PubMed Central

Background and Aims The root meristem of the Arabidopsis thaliana mature embryo is a highly organized structure in which individual cell shape and size must be regulated in co-ordination with the surrounding cells. The objective of this study was to determine the role of the AUX1 LAX family of auxin import carriers during the establishment of the embryonic root cell pattern. Methods The radicle apex of single and multiple aux1 lax mutant mature embryos was used to evaluate the effect of this gene family upon embryonic root organization and root cap size, cell number and cell size. Key Results It was demonstrated here that mutations within the AUX1 LAX family are associated with changes in cell pattern establishment in the embryonic quiescent centre and columella. aux1 lax mutants have a larger radicle root cap than the wild type and this is associated with a significant increase in the root-cap cell number, average cell size, or both. Extreme disorganization of the radicle apex was observed among quadruple aux1 lax1 lax2 lax3 mutant embryos, but not in single aux1 null or in lax1, lax2 and lax3 single mutants, indicating redundancy within the AUX1 LAX family. Conclusions It was determined that the AUX1 LAX family of auxin influx facilitators participates in the establishment of cell pattern within the apex of the embryonic root in a gene-redundant fashion. It was demonstrated that aux1 lax mutants are affected in cell proliferation and cell growth within the radicle tip. Thus AUX1 LAX auxin importers emerge as new players in morphogenetic processes involved in patterning during embryonic root formation.

Ugartechea-Chirino, Yamel; Swarup, Ranjan; Swarup, Kamal; Peret, Benjamin; Whitworth, Morag; Bennett, Malcolm; Bougourd, Sue

2010-01-01

346

Exposition pr?coce aux aliments et allergies alimentaires chez les enfants  

PubMed Central

Résumé Question J’étais sous l’impression qu’on devrait éviter de donner aux nourrissons des aliments potentiellement allergènes comme des noix, du lait de vache et des œufs pour prévenir le développement de réactions allergiques. Quels conseils devrait-on donner aux parents concernant l’introduction des aliments durant la petite enfance et le développement des allergies alimentaires? Réponse Il n’y a pas de données probantes indiquant que retarder l’introduction d’aliments particuliers après l’âge de 6 mois aide à prévenir les allergies. Une récente déclaration de la Société canadienne de pédiatrie ne recommande aucun délai quant à l’introduction d’aliments durant la petite enfance. De récentes études de recherche semblent aussi faire valoir que l’introduction précoce (entre 4 et 6 mois) d’aliments possiblement allergènes procure une forme de protection et contribue à prévenir les allergies, mais il faudrait plus de recherche à ce sujet.

Chin, Benetta; Chan, Edmond S.; Goldman, Ran D.

2014-01-01

347

Auxin-nonresponsive grape Aux/IAA19 is a positive regulator of plant growth.  

PubMed

We report the characterization of VvIAA19, an auxin/indole-3-acetic acid (Aux/IAA) protein, in grapevine (Vitis vinifera L.). VvIAA19 was expressed abundantly in berries. VvIAA19 transcription was rapidly increased at pre-anthesis and then decreased during fruit set. Before véraison, however, VvIAA19 gene expression was upregulated again and maximum expression was maintained until the end of ripening. Exogenous IAA did not induce VvIAA19 expression in grape leaves, suggesting that VvIAA19 might be auxin-nonresponsive. The overexpression of VvIAA19 in Arabidopsis thaliana had a notable effect on plant growth. Although no morphological changes were observed, transgenic Arabidopsis plants overexpressing VvIAA19 exhibited faster growth, including root elongation and floral transition, than the control plant, suggesting that the constitutive expression of VvIAA19 protein resulted in increased growth rates without any detectable harm. Taken together, we conclude that grape Aux/IAA19 protein is likely to play a crucial role as a plant growth regulator. PMID:21562765

Kohno, Minako; Takato, Haruka; Horiuchi, Haruka; Fujita, Keiko; Suzuki, Shunji

2012-02-01

348

Le silicium nanoporeux: microstructuration diélectrique et application aux structures photoniques avancées  

NASA Astrophysics Data System (ADS)

The aim of this work is to elaborate and study photonic bandgap microstructures using nanoporous silicon. Planar microstructures like microcavities are first considered, and their influence on both angular and spectral distributions of photoluminescence are investigated. The primary conclusion derived from these studies is that it is essential to control the propagation of light in the plane, too. Thus, the lateral propagation of light, enhanced by a vertical structuring of the optical index (step-index waveguide as well as Bragg reflection waveguide) is studied. Furthermore, a numerical model based on the standard transfer-matrix method is suggested to calculate guiding losses. Finally, a holographic process is utilized to obtain a lateral structuring of the optical index, thereby allowing the investigation of its effects on the guided light. The transmittance, measured on a multimode waveguide using white light, shows several stopbands, which are attributed to diagonal and off-diagonal couplings. The comparison of these measurements to the coupled-mode theory allows a map of the optical index to be plotted. A strong birefringence in regions that were illuminated during the holographic process was illustrated. This suggests a stronger decrease of the extraordinary index (? n = -0.4) than the ordinary index (? n = -0.22). With a period of 450 nm, these values of index contrast are promising, even if the effective depth on which the index is modulated is only 0.5 ?m. Ce travail est consacré à la réalisation et à l'étude de microstructures photoniques à base de silicium nanoporeux. Nous commençons notre étude par des structures planaires de type microcavité, dont nous caractérisons l'influence sur la photoluminescence du matériau, en termes de redistribution spectrale et angulaire. Il apparaît très vite la nécessité de contrôler la propagation de la lumière dans le plan de la structure. Aussi, nous cherchons d'abord à favoriser la propagation latérale au moyen d'une structuration verticale de l'indice, et nous étudions le guidage au moyen de deux types de structures, exploitant soit à un guidage conventionnel par réflexion totale interne, soit à un guidage par réflexion de Bragg. À cette occasion nous proposons une méthode numérique, basée sur le formalisme des matrices de transfert, permettant de calculer l'atténuation de la puissance transportée dans le plan. Par la suite, nous mettons à profit le procédé holographique de structuration d'indice démontré par des travaux antérieurs et étudions son influence sur la lumière guidée. La transmission, mesurée en lumière blanche sur un guide multimode révèle de multiples bandes interdites que nous interprétons en termes de couplages diagonaux et non diagonaux. La confrontation des mesures avec une modélisation par la méthode des modes couplés nous permet d'établir une carte d'indice de notre structure. Il apparaît une biréfringence marquée dans les régions insolées par le procédé holographique, caractérisées par une diminution deux fois plus importante de l'indice extraordinaire (? n =-0{,}4) que de l'indice ordinaire (? n =-0{,}22). Avec une période de 450 nm, ces valeurs de contraste sont encourageantes, bien que la modulation d'indice ne soit présente que sur une profondeur effective de l'ordre de 0,5 ?m.

Ferrand, P.

2002-03-01

349

Le coussinet adipeux de Charpy. Anatomie descriptive et fonctionnelle. Applications aux nouveaux liftings  

Microsoft Academic Search

The eyebrow fat pad, or retro-orbicularis oculus fat (ROOF) is a syssarcosis, described as an anatomic and functional unity by M. Charpy in 1909. Our anatomic study on 12 (24 half-head) fresh cadaver specimens confirm anatomic variations, mainly according to age and sex. Synthesis of recent literature shows the renewed interest for this fat pad and its involvement in the eye's

F. Aghai; P. Caix

2004-01-01

350

La diffraction des rayons X durs : un nouvel outil pour les géosciences. Application aux quartz naturels  

NASA Astrophysics Data System (ADS)

The Institut Laue-Langevin hard X ray diffraction technique has been used to study natural quartz crystals from the Alps and Madagascar. The results are consistent with the known descriptions of these types of crystals. This technique presents the advantage to be directly related to the structural properties of the samples. These measurements show the interest of this non destructive technique, which allows global bulk analysis of centimeter size samples, in the field of mineralogy and geosciences. It completes information given by usual methods.

Bastie, P.; Dolino, G.; Hamelin, B.; Meisser, N.

2004-11-01

351

REFORMES ECONOMIQUES ET CROISSANCE PRO-PAUVRE : UNE APPLICATION MACRO-MICRO AUX PHILIPPINES  

Microsoft Academic Search

Dans la perspective d’une réduction accélérée de la pauvreté et l’atteinte des objectifs du millénaire pour le développement, une riche littérature sur la croissance pro-pauvre s’est développée à partir du milieu des années 90 et propose des réformes pour générer une croissance soutenue tout en améliorant les revenus et les conditions de vie des pauvres. Mais les analyses pour l’impact

Dorothée Boccanfuso; Rodolphe Missinhoun; Luc Savard

2007-01-01

352

Profile structures of the voltage-sensor domain and the voltage-gated K+-channel vectorially oriented in a single phospholipid bilayer membrane at the solid-vapor and solid-liquid interfaces determined by x-ray interferometry  

NASA Astrophysics Data System (ADS)

One subunit of the prokaryotic voltage-gated potassium ion channel from Aeropyrum pernix (KvAP) is comprised of six transmembrane ? helices, of which S1-S4 form the voltage-sensor domain (VSD) and S5 and S6 contribute to the pore domain (PD) of the functional homotetramer. However, the mechanism of electromechanical coupling interconverting the closed-to-open (i.e., nonconducting-to-K+-conducting) states remains undetermined. Here, we have vectorially oriented the detergent (OG)-solubilized VSD in single monolayers by two independent approaches, namely “directed-assembly” and “self-assembly,” to achieve a high in-plane density. Both utilize Ni coordination chemistry to tether the protein to an alkylated inorganic surface via its C-terminal His6 tag. Subsequently, the detergent is replaced by phospholipid (POPC) via exchange, intended to reconstitute a phospholipid bilayer environment for the protein. X-ray interferometry, in which interference with a multilayer reference structure is used to both enhance and phase the specular x-ray reflectivity from the tethered single membrane, was used to determine directly the electron density profile structures of the VSD protein solvated by detergent versus phospholipid, and with either a moist He (moderate hydration) or bulk aqueous buffer (high hydration) environment to preserve a native structure conformation. Difference electron density profiles, with respect to the multilayer substrate itself, for the VSD-OG monolayer and VSD-POPC membranes at both the solid-vapor and solid-liquid interfaces, reveal the profile structures of the VSD protein dominating these profiles and further indicate a successful reconstitution of a lipid bilayer environment. The self-assembly approach was similarly extended to the intact full-length KvAP channel for comparison. The spatial extent and asymmetry in the profile structures of both proteins confirm their unidirectional vectorial orientation within the reconstituted membrane and indicate retention of the protein's folded three-dimensional tertiary structure upon completion of membrane bilayer reconstitution. Moreover, the resulting high in-plane density of vectorially oriented protein within a fully hydrated single phospholipid bilayer membrane at the solid-liquid interface will enable investigation of their conformational states as a function of the transmembrane electric potential.

Gupta, S.; Liu, J.; Strzalka, J.; Blasie, J. K.

2011-09-01

353

Twinkling Fractal Theory of the Glass Transition: Applications and Insights  

NASA Astrophysics Data System (ADS)

The new perspective on the Glass Transition of amorphous materials offered by theTwinkling Fractal Theory (TFT). [R. P. Wool, J. Polym. Sci, Part B: Polym Phys. 46, 2765 (2008)] is examined in several applications. The TFT describes Tg in terms of the autocorrelation relaxation function for the spatio-temporal solid-liquid fluctuations which are related to the vibrational frequencies (``twinkles'') described by the Orbach vibrational density of states for a fractal. The twinkling frequencies for solid-liquid interchange are due to Boltzmann energy populations of interatomic oscillators interacting through anharmonic potentials U(x) with energy Do of order 1-5 kcal/mol. Tg occurs when the activation energy for the solid-liquid transition goes to zero at the inflection point of U(x) and is given by Tg = 2Do/9k. The applications include: (a) group contributions to Do, (b) the rate and temperature dependence of yielding and fracture, (c) shear thickening fluids, (d) rate dependence of dynamical mechanical properties, particularly the tan delta damping peak used to measure Tg, (e) derivation of the empirical WLF time-temperature superposition empirical relation, (f) thermal expansion and (g) physical aging.

Wool, Richard

2009-03-01

354

The Tomato Aux/IAA Transcription Factor IAA9 Is Involved in Fruit Development and Leaf MorphogenesisW?  

PubMed Central

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.

Wang, Hua; Jones, Brian; Li, Zhengguo; Frasse, Pierre; Delalande, Corinne; Regad, Farid; Chaabouni, Salma; Latche, Alain; Pech, Jean-Claude; Bouzayen, Mondher

2005-01-01

355

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

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

Moreta, Cristina; Tena, María Teresa

2014-08-15

356

Application of the constrained fluid lambda-integration path to the calculation of high temperature Au(110) surface free energies  

Microsoft Academic Search

Recently a method termed constrained fluid lambda-integration was proposed for calculating the free energy difference between bulk solid and liquid reference states via the construction of a reversible thermodynamic integration path; coupling the two states in question. The present work shows how the application of the constrained fluid lambda-integration concept to solid\\/liquid slab simulation cells makes possible a generally applicable

Gregory Grochola; Ian K. Snook; Salvy P. Russo

2005-01-01

357

Enzymatic probe sonication as a tool for solid-liquid extraction for total selenium determination by electrothermal-atomic absorption spectrometry.  

PubMed

A new fast and reproducible approach is described for the application of the enzymatic probe sonication (EPS) methodology [J.L. Capelo, P. Ximénez-Embún, Y. Madrid-Albarrán, C. Cámara, Anal. Chem. 76 (2004) 233-237] for total selenium determination by electrothermal atomic absorption spectrometry, ET-AAS. Ni(NO3)2 and Pd(NO3)2 were studied as matrix modifiers in conjunction with H2O2, being best results obtained with Pd(NO3)2 plus H2O2. The presence of H2O2 as matrix modifier increases up to 66% the time-life of the graphite tubes, by avoiding the building-up of carbonaceous residues. BCR-414 plankton and ERM-CE 278 mussel tissue reference materials were used for proof-of-the-methodology. Different enzymes, protease XIV, substilisin and trypsin were studied. The use of fresh enzyme was found critical. Good Se recoveries were obtained for oyster tissue, 111%; BCR-414 plankton, 106% and ERM-CE 278 mussel tissue, 93%, when protease XIV was used. Data regarding microwave digestion versus EPS methodology is also presented and discussed. PMID:18371630

Vale, G; Pereira, S; Mota, A; Fonseca, L; Capelo, J L

2007-11-30

358

Carbon nanotube reinforced hollow fiber solid/liquid phase microextraction: a novel extraction technique for the measurement of caffeic acid in Echinacea purpurea herbal extracts combined with high-performance liquid chromatography.  

PubMed

A new design of hollow fiber solid-liquid phase microextraction (HF-SLPME) was developed for the determination of caffeic acid in medicinal plants samples as Echinacea purpure. The membrane extraction with sorbent interface used in this research is a three-phase supported liquid membrane consisting of an aqueous (donor phase), organic solvent/nano sorbent (membrane) and aqueous (acceptor phase) system operated in direct immersion sampling mode. The multi-walled carbon nanotube dispersed in the organic solvent is held in the pores of a porous membrane supported by capillary forces and sonification. It is in contact with two aqueous phases: the donor phase, which is the aqueous sample, and the acceptor phase, usually an aqueous buffer. All microextraction experiments were supported using an Accurel Q3/2 polypropylene hollow fiber membrane (600 microm I.D., 200 microm wall thicknesses, and 0.2 microm pore size). 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 an acidic analyte into one single extract. In order to obtain high enrichment and extraction efficiency of the analyte using this novel technique, the main parameters were optimized. Under the optimized extraction conditions, the method showed good linearity (0.0001-50 microg/L), repeatability, low limits of detection (0.00005 microg/L) and excellent enrichment (EF=2108). PMID:20227700

Es'haghi, Zarrin; Golsefidi, Mazyar Ahmadi; Saify, Ali; Tanha, Ali Akbar; Rezaeifar, Zohre; Alian-Nezhadi, Zahra

2010-04-23

359

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

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 waste.

Phillips, D.C.

2006-05-16

360

Efficacité d'un programme d'entraînement aux habiletés sociales pour enfants présentant des diagnostics psychiatriques hétérogènes  

Microsoft Academic Search

Le but de cette étude était d'évaluer les effets d'un programme d'entraînement aux habiletés sociales conçu pour des enfants de 9 à 14 ans présentant des problèmes de santé mentale et des difficultés relationnelles. Le programme (offert en clinique externe) combine des techniques de l'apprentissage social et de l'approche cognitivo-comportementale. Les participants (N = 51; âge moyen = 10,8 ans;

Lyse Lessard; Sylvain Coutu

2011-01-01

361

Un système de détection à pixels tolérant aux rayonnements pour les expériences ALICE et LHCb au CERN  

Microsoft Academic Search

Le travail présenté dans cette thèse a été effectué au sein du groupe Microélectronique du CERN, le laboratoire européen pour la physique des particules. Il s’agit d’un laboratoire situé près de Genève en Suisse, il a été créé dans les années 50 pour donner aux scientifiques européens les moyens d'étudier la physique des hautes énergies (HEP, High Energy Physics). Grâce

Roberto Dinapoli; Jean Gasiot

2004-01-01

362

Phloem-specific expression of a melon Aux/IAA in tomato plants alters auxin sensitivity and plant development.  

PubMed

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

Golan, Guy; Betzer, Rotem; Wolf, Shmuel

2013-01-01

363

Topotaxial fabrication of vertical Aux Ag1-x nanowire arrays: plasmon-active in the blue region and corrosion resistant.  

PubMed

Topotaxial growth of Au(x) Ag(1-x) alloy nanowires (NWs) by postepitaxial deposition of Ag vapor on Au NWs and investigation of their plasmonic properties are reported. Ag vapor is supplied onto the epitaxially grown Au NWs, topotaxially turning them into Au(x) Ag(1-x) alloy NWs. The original geometries and alignments of the Au nanostructures are well preserved, while the composition of the alloy NWs is controlled by varying the Ag vapor supply time. The Au(0.5) Ag(0.5) NWs show high surface-enhanced Raman scattering (SERS) activity comparable to that of Ag NWs as well as highly increased oxidation resistance. The plasmon-active wavelength range of the Au(0.5) Ag(0.5) NW is significantly extended to the blue region compared to Au NWs. The Au(x) Ag(1-x) alloy NWs that have plasmonic activity in the blue region in addition to high corrosion resistance will make a superb material for practical plasmonic devices including SERS sensors and optical nanoantennas. PMID:22431295

Lee, Hyoban; Yoo, Youngdong; Kang, Taejoon; In, Juneho; Seo, Min-Kyo; Kim, Bongsoo

2012-05-21

364

Penny Perfect Properties (Solid-Liquid Interactions)  

NSDL National Science Digital Library

Students investigate the property dependence between liquid and solid interfaces and determine observable differences in how liquids react to different solid surfaces. They compare copper pennies and plastic "coins" as the two test surfaces. Using an eye dropper to deliver various fluids onto the surfaces, students determine the volume and mass of a liquid that can sit on the surface. They use rulers, scales, equations of volume and area, and other methods of approximation and observation, to make their own graphical interpretations of trends. They apply what they learned to design two super-surfaces (from provided surface treatment materials) that arecapable of holding the most liquid by volume and by mass. Cost of materials is a parameter in their design decisions.

CREAM GK-12 Program, Engineering Education Research Center, College of Engineering and Architecture,

365

Solid–liquid diffusion controlled rate equations  

Microsoft Academic Search

The paper is concerned with diffusion controlled reaction mechanisms and the associated rate equations. A review of previously reported rate equations was carried out and reported with the proofs of the equations. Three new rate equations are proposed based on the reaction of a solid and a liquid phase. Isothermal and non-isothermal experimental data was obtained for the reaction of

C. F. Dickinson; G. R. Heal

1999-01-01

366

Electrical Breakdown at Solid-Liquid Interfaces  

Microsoft Academic Search

Observations of the electrohydrodynamic (EHD) motion of insulating oils in a static electric field, between plane parallel electrodes separated by an insulating support, are reported. A transition from laminar to turbulent flow in the bridged gap is observed near breakdown voltages. Velocity measurements support the observations of the onset of turbulent flow prior to flashoever while photographic observations show the

Edward Cherney; James Cross

1977-01-01

367

Enzyme adsorption at solid-liquid interfaces  

Microsoft Academic Search

Enzymes are proteins with the capacity of catalysing various reactions. Nowadays two types of enzymes, proteases and lipases, are available for use in detergent formulations for household and industrial laundry washing. Proteases are capable of catalysing the hydrolysis of proteins while lipases enable the hydrolysis of glycerol esters, the main component in fats and non-mineral oils. In this study, two

S. Duinhoven

1992-01-01

368

Water as a solid, liquid, and gas  

NSDL National Science Digital Library

The representation is a set of 3 diagrams, with accompanying text explanations, showing the arrangement of water molecules in each of its three states of matter and an activity that uses BB's and petri dishes to create models of ice, liquid water, and water vapor.

369

Pipeline Flow of Solids-Liquid Suspensions.  

National Technical Information Service (NTIS)

Suspensions containing closely sized beads of varying diameters, made from two types of glass, were allowed to flow through 2, 1 and 1/2 inch pipelines. Available slurry flow data in 1/2 inch pipe using glass, steel, and lead particles were combined with ...

R. Turian T. F. Yuan G. Mauri

1970-01-01

370

Xe{sup +} formation following photolysis of Au-Xe: A velocity map imaging study  

SciTech Connect

The photodissociation dynamics of Au-Xe leading to Xe{sup +} formation via the {Xi}{sub 1/2}-X{sup 2}{Sigma}{sup +} (v{sup '}, 0) band system (41 500-41 800 cm{sup -1}) have been investigated by velocity map imaging. Five product channels have been indentified, which can be assigned to photoinduced charge transfer followed by photodissociation in either the neutral or the [Au-Xe]{sup +} species. For the neutral species, charge transfer occurs via a superexcited Rydberg state prior to dissociative ionization, while single-photon excitation of the gold atom in Au{sup +}-Xe accesses an (Au{sup +})*-Xe excited state that couples to a dissociative continuum in Au-Xe{sup +}. Mechanisms by which charge transfer occurs are proposed, and branching ratios for Xe{sup +} formation via the superexcited Rydberg state are reported. The bond dissociation energy for the first excited state of Au{sup +}-Xe is determined to be {approx}9720 {+-} 110 cm{sup -1}.

Hopkins, W. Scott; Woodham, Alex P.; Mackenzie, Stuart R. [Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford OX1 3QZ (United Kingdom); Plowright, Richard J.; Wright, Timothy G. [School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom)

2011-03-07

371

Time perspectives on glacial landscape formation - glacial flow chronology at Lac aux Goélands, northeastern Québec, Canada  

NASA Astrophysics Data System (ADS)

We used mapping from aerial photographs and field investigations around Lac Aux Goélands (Whitegull Lake), northeastern Québec, to establish a glacial flow chronology that involves three different glacial landform systems. We interpret the youngest of these systems as related to the late Wisconsinan deglaciation. This system has an up-glacier discontinuity that marks a temporal shift from warm-based subglacial conditions to non-erosive cold-based subglacial conditions, whereby older glacial landscapes are preserved in the interior of Québec-Labrador. Furthermore, our results support theories suggesting a northward migrating ice divide to a final position south of Ungava Bay during the final deglaciation. The recognition that a glacial landscape is fragmented and consists of smaller, temporally unrelated units is of considerable significance in understanding ice-sheet dynamics and patterns of subglacial preservation and destruction. This is because a fragmented landscape implies a fragmented formation history, where formation of subglacial landforms occurred in restricted subglacial zones during restricted time periods. Periods of formation must have been separated by periods of preservation and inhibited subglacial reshaping. Based on estimates of the ice margin retreat velocity and the velocity of the warm-based inward migrating zone, we suggest that periods of preservation were orders of magnitude longer than periods of subglacial landform formation.

Clarhäll, Anders; Jansson, Krister N.

2003-07-01

372

Phloem-mobile Aux/IAA transcripts target to the root tip and modify root architecture.  

PubMed

In plants, the phloem is the component of the vascular system that delivers nutrients and transmits signals from mature leaves to developing sink tissues. Recent studies have identified proteins, mRNA, and small RNA within the phloem sap of several plant species. It is now of considerable interest to elucidate the biological functions of these potential long-distance signal agents, to further our understanding of how plants coordinate their developmental programs at the whole-plant level. In this study, we developed a strategy for the functional analysis of phloem-mobile mRNA by focusing on IAA transcripts, whose mobility has previously been reported in melon (Cucumis melo cv. Hale's Best Jumbo). Indoleacetic acid (IAA) proteins are key transcriptional regulators of auxin signaling, and are involved in a broad range of developmental processes including root development. We used a combination of vasculature-enriched sampling and hetero-grafting techniques to identify IAA18 and IAA28 as phloem-mobile transcripts in the model plant Arabidopsis thaliana. Micro-grafting experiments were used to confirm that these IAA transcripts, which are generated in vascular tissues of mature leaves, are then transported into the root system where they negatively regulate lateral root formation. Based on these findings, we present a model in which auxin distribution, in combination with phloem-mobile Aux/IAA transcripts, can determine the sites of auxin action. PMID:22925478

Notaguchi, Michitaka; Wolf, Shmuel; Lucas, William J

2012-10-01

373

Tectonic conditions of hydrothermal polymetallic vein-type mineralization, Sainte Marie-aux-Mines, France  

NASA Astrophysics Data System (ADS)

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-W strike-slip faults. Early strike-slip movements are assessed by the presence of striated iron oxides, the crystallization of which is considered to be early during the ore deposition process. Mineralizing fluids were probably fluorine-rich as F-bearing minerals, sericite, chlorite and apatite are present in the chlorite zone associated with early sulphide-rich ores. The E-W mineralized faults are only easily compatible with the tectonics known in Permian times. c) Late-stage faults - These could be related to the numerous changes in plate configuration which occur during the Mesozoic and Cenozoic times, in accordance with the creation of the Paris basin, the opening of Atlantic ocean and Rhine Graben, as well as with the Tethys closure. For example, the vertical lineation superposed on an horizontal lineation observed on mineralized rocks indicate reactivation of the former E-W mineralized veins under a normal movement. The latter may correspond to an extensive regime known during Oligocene times. On the other hand, one of the major late-stage faults strikes N-S and is related to a dextral strike-slip system, which could be considered as Miocene. It is expected that fluid remobilization occurred during fault reactivation, a process which could have led to successive ore deposition following the emplacement of the major E-W mineralized veins. A fluid inclusion study in the gangue minerals of the Gabe Gottes is now under investigation. This together with isotopic studies will help to determine the source of the mineralizing fluids, as well as the conditions of ore deposition. Keywords: Faults, polymetallic mineralization, variscan orogeny, Gabe-Gottes, Sainte-Marie-aux-Mines, Vosges, F-rich fluids.

Hafeznia, Y.; Bourlange, S.; Ohnenstetter, M.

2012-04-01

374

La racialisation de la sante publique aux Etats-Unis : entre pouvoir sur la vie et droit de laisser mourir.  

PubMed

RSUM Aux États-Unis, une intensification de l'usage de la race en santé publique a récemment été notée ; une idée qui est pourtant controversée dans les sciences. La race a été vue dans ce contexte comme un objet de discours entre pouvoirs et savoirs, un objet qui se réfère au corps devenu au cours des derniers siècles un site discursif pour représenter la différence. Cet article s'appuie sur une analyse de documents de la santé publique parus aux États-Unis et issus de bureaux fédéraux et d'une importante revue spécialisée dans le domaine sanitaire, qui ont été publiés entre 2001 et 2009. Cette étude a analysé la manière dont la race est représentée, produite comme objet de connaissance et régulée par les pratiques discursives dans ces documents. Les résultats décrivent deux processus enchevêtrés, la racialisation et la sanitarisation, qui concourent à reformuler l'idée de race. Le premier est un ensemble d'opérations qui visent à identifier, à situer et à opposer les sujets et les groupes à partir de labels standardisés. La sanitarisation assure la traduction des groupes racialisés en termes de maladies, de comportements, de vie ou de mort. Ces pratiques aboutissent à la caractérisation et à la formation d'objets racialisés et sanitarisés et à des stéréotypes ; un ensemble d'opérations qui a tendance à naturaliser la différence. La racialisation apparaît également tiraillée entre un pouvoir sur la vie et un droit de laisser mourir. Enfin, cette étude propose aux acteurs de la santé publique de sortir des frontières imposées par le discours racialisant. PMID:24801319

Cloos, Patrick

2012-03-01

375

Genome-wide analysis of Aux/IAA gene family in Solanaceae species using tomato as a model.  

PubMed

Auxin plays key roles in a wide variety of plant activities, including embryo development, leaf formation, phototropism, fruit development and root initiation and development. Auxin/indoleacetic acid (Aux/IAA) genes, encoding short-lived nuclear proteins, are key regulators in the auxin transduction pathway. But how they work is still unknown. In order to conduct a systematic analysis of this gene family in Solanaceae species, a genome-wide search for the homologues of auxin response genes was carried out. Here, 26 and 27 non redundant AUX/IAAs were identified in tomato and potato, respectively. Using tomato as a model, a comprehensive overview of SlIAA gene family is presented, including the gene structures, phylogeny, chromosome locations, conserved motifs and cis-elements in promoter sequences. A phylogenetic tree generated from alignments of the predicted protein sequences of 31 OsIAAs, 29 AtIAAs, 31 ZmIAAs, and 26 SlIAAs revealed that these IAAs were clustered into three major groups and ten subgroups. Among them, seven subgroups were present in both monocot and dicot species, which indicated that the major functional diversification within the IAA family predated the monocot/dicot divergence. In contrast, group C and some other subgroups seemed to be species-specific. Quantitative real-time PCR (qRT-PCR) analysis showed that 19 of the 26 SlIAA genes could be detected in all tomato organs/tissues, however, seven of them were specifically expressed in some of tomato tissues. The transcript abundance of 17 SlIAA genes were increased within a few hours when the seedlings were treated with exogenous IAA. However, those of other six SlIAAs were decreased. The results of stress treatments showed that most SIIAA family genes responded to at least one of the three stress treatments, however, they exhibited diverse expression levels under different abiotic stress conditions in tomato seedlings. SlIAA20, SlIAA21 and SlIAA22 were not significantly influenced by stress treatments even though at least one stress-related cis-element was identified in their promoter regions. In conclusion, our comparative analysis provides an insight into the evolution and expression patterns in various tissues and in response to auxin or stresses of the Aux/IAA family members in tomato, which will provide a very useful reference for cloning and functional analysis of each member of AUX/IAA gene family in Solanaceae crops. PMID:22314799

Wu, Jian; Peng, Zhen; Liu, Songyu; He, Yanjun; Cheng, Lin; Kong, Fuling; Wang, Jie; Lu, Gang

2012-04-01

376

Croissance Par Epitaxie EN Phase Vapeur aux Organo - et Caracterisation des Heterostructures Contraintes a Base de Phosphur de Indium  

Microsoft Academic Search

Trois systemes heteroepitaxiaux a base de InP:InP\\/Si, InAs\\/InP et InAsP\\/InP ont ete fabriques par epitaxie en phase vapeur aux organo-metalliques (EPVOM)conventionelle. En plus l'epitaxie par couches atomiques (ECA) a ete utilisee pour fabriquer des puits quantiques ultra-minces et des superreseaux a courte periode InAs\\/InP. L'epitaxie de InP sur le silicium pose des problemes lies a un desaccord de maille de

Chuong Anh Tran

1994-01-01

377

Cinetique de la nucleation binaire non-isotherme et de la condensation binaire aux conditions dynamiques  

NASA Astrophysics Data System (ADS)

La présente thèse est consacrée à la théorie de la condensation binaire. Premièrement, nous considérons la thermodynamique de la nucléation binaire, en nous concentrant sur l'énergie libre de formation d'une goutte et la distribution d'équilibre des gouttes, qui est essentielle pour la vitesse théorique de nucléation et dont le choix n'est toutefois pas unique. Une nouvelle distribution d'équilibre est proposée. Deuxièmement, nous développons la théorie cinétique de la nucléation binaire non-isotherme. Cette théorie traite de l'influence des effets thermiques sur la condensation binaire qui sont causés par la chaleur de condensation. Les molécules du mélange de vapeurs absorbées par une goutte de solution binaire lui transmettent de la chaleur de condensation, tandis que les molécules émises par la goutte lui enlèvent une telle chaleur. La température moyenne de la goutte s'accroît au fur et à mesure qu'elle grandit. Cet échauffement des gouttes croissantes diminue la vitesse de nucléation et influence d'autres caractéristiques du processus. Dans le cas où les chaleurs de condensation sont très petites par rapport à la fluctuation efficace de l'énergie d'une goutte l'équation cinétique peut être réduite à celle de Fokker et Planck. L'analyse de l'équation cinétique permet de déterminer la hiérarchie des échelles de temps de la nucléation binaire non-isotherme. Cela rend possible de séparer et décrire analytiquement l'étape de relaxation thermique pendant laquelle la distribution des gouttes selon la température s'approche d'une gaussienne, alors que leur distribution selon les nombres de molécules ne change guère. Finalement, nous étudions la condensation binaire isotherme aux conditions dynamiques. Dans ce cas la formation et la croissance des gouttes se passent en même temps que la métastabilité du mélange de vapeurs croît graduellement, atteint son maximum et décroît. C'est ainsi que la condensation binaire se passe le plus souvent dans la nature. Nous développons la théorie cinétique de ces processus pour les systèmes ouverts ainsi que pour les systèmes fermés (du point de vue de l'échange de matière entre le système où la condensation se passe et son environnement). Les deux sursaturations idéales que les vapeurs du mélange auraient eues en absence d'absorption de la substance par les gouttes sont déterminées par les conditions extérieures: la dépendance temporelle des sursaturations idéales est considérée comme donnée. De même, cette méthode permet de trouver la dépendance temporelle des sursaturations réelles des deux vapeurs et le nombre total de gouttes. (Abstract shortened by UMI.)

Djikaev, Yuri

378

Etude de la microstructure d'un acier 316 titane apres vieillissement et apres irradiation aux neutrons  

NASA Astrophysics Data System (ADS)

La précipitation qui se produit lors de vieillissements de longue durée entre 450 et 700°C dans un acier 316 Ti soit hypertrempé soit écroui, a été étudiée en couplant les techniques de microscopic électronique et de microanalyse X. Pour les cas expérimentaux étudiés, les résultats obtenus montrent que la composition des carbures M 23C 6 et des phases ?, Laves et ? est peu sensible aux conditions de vieillissement et dépend également peu de l'état structural initial. Leur teneur en éléments principaux de l'alliage est d'ailleurs voisine de celle des phases précipitées dans l'acier non stabilisé. Excepté les carbures de type M 6C, toutes ces phases ont une teneur en nickel inférieure à celle de la matrice. Les premiers rérultats obtenus sur des matériaux irradiés aux neutrons montrent que la précipitation sous flux est différente de celle qui se produit dans l'acier vieilli. Les phases ?' et G ainsi que les carbures riches en nickel ont été observés. L'attention a été attirée sur le fait qu'il n'y a pas de corrélation simple entre la vitesse de gonflement et la teneuer résiduelle en nickel de la matrice.

Brun, G.; Le Naour, J.; Vouillon, M.

1981-10-01

379

ERADICATION OF CROWN OF THORNS STARFISH (ACANTHASTER PLANCI) INFESTATION IN A PATCH REEF IN THE LAGOON OFF ILE AUX CERFS, MAURITIUS  

Microsoft Academic Search

The Crown of Thorns (COTs) starfish is a natural predator of live corals. It was observed in unusually high numbers in the patch reef between Ile aux Cerfs and the fringing reef. This paper describes how Crown of Thorns infestation was effectively controlled by injection of dry acid in situ through diving without any adverse effect on the marine environment

V Mangar

380

Les managers de proximité et les changements : quels sont les difficultés, les rôles et les comportements des Chefs de groupe face aux changements organisationnels ?  

Microsoft Academic Search

Alors que les organisations sont de plus en plus souvent confrontées à des problématiques de changements, le taux de réussite de leur mise en oeuvre reste relativement faible. De par leur positionnement particulier dans l'organisation, les managers de proximité ont une incidence forte sur la réussite ou l'échec des changements. Or, la littérature consacrée aux changements ne traite que très

Jérémy Vignal

2011-01-01

381

RAC GTPases in Tobacco and Arabidopsis Mediate Auxin-Induced Formation of Proteolytically Active Nuclear Protein Bodies That Contain AUX/IAA ProteinsW?  

PubMed Central

Auxin signaling relies on ubiquitin ligase SCFTIR1-mediated 26S proteasome-dependent proteolysis of a large family of short-lived transcription regulators, auxin/indole acetic acid (Aux/IAA), resulting in the derepression of auxin-responsive genes. We have shown previously that a subset of Rac GTPases is activated by auxin, and they in turn stimulate auxin-responsive gene expression. We show here that increasing Rac signaling activity promotes Aux/IAA degradation, whereas downregulating that activity results in the reduction of auxin-accelerated Aux/IAA proteolysis. Observations reported here reveal a novel function for these Rac GTPases as regulators for ubiquitin/26S proteasome-mediated proteolysis and further consolidate their role in auxin signaling. Moreover, our study reveals a cellular process whereby auxin induces and Rac GTPases mediate the recruitment of nucleoplasmic Aux/IAAs into proteolytically active nuclear protein bodies, into which components of the SCFTIR1, COP9 signalosome, and 26S proteasome are also recruited.

Tao, Li-zhen; Cheung, Alice Y.; Nibau, Candida; Wu, Hen-ming

2005-01-01

382

Anisotropy of the magnetic susceptibility of CeCu6-xAux near the quantum phase transition  

NASA Astrophysics Data System (ADS)

We report on the low-temperature dc magnetic susceptibility of CeCu6-xAux(x=0.1) in very small fields B=100 ?T and 1 mT. For x=0.1, i.e. for the quantum critical concentration, we confirm the anomalous exponent ? of the susceptibility along the easy c-direction, ?c-1??+T? with ?=0.8 observed previously in moderate fields B=100 mT (see, A. Schröder, et al., Nature 407 (2000) 351). However, below 240 mK we see a clear additional contribution to ?c. At the lowest measuring temperature T=40 mK, the ratio ?c:?a:?b=4:1.5:1 of the susceptibility anisotropy is weaker than at higher T where the ratio is 10:2:1. This is caused by a steeper increase of ?a and ?b as compared to ?c.

Tomanic, T.; Hamann, A.; Löhneysen, H. v.

2008-04-01

383

Conception et test d'un circuit integre (ASIC): application aux chambres multifils et aux photomultiplicateurs de l'experience GRAAL. (Conception and test of an integrated circuit (ASIC): application to multiwire chambers and photomultipliers of the GRAAL experience).  

National Technical Information Service (NTIS)

The nuclear physics project GRAAL (GRenoble Anneau Accelerateur Laser) located at the European Synchrotron Radiation Facility (ESRF) in Grenoble produces a high energy photon beam with a maximum energy of 1.5 GeV. This gamma beam is obtained by Compton ba...

H. Bugnet

1995-01-01

384

Diversification and Expression of the PIN, AUX/LAX, and ABCB Families of Putative Auxin Transporters in Populus  

PubMed Central

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.

Carraro, Nicola; Tisdale-Orr, Tracy Eizabeth; Clouse, Ronald Matthew; Knoller, Anne Sophie; Spicer, Rachel

2012-01-01

385

The French Tsunami warning center for the Mediterranean and North-East Atlantic (CENtre d'ALerte aux Tsunamis, CENALT)  

NASA Astrophysics Data System (ADS)

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 ready to act as Candidate Watch Provider covering Western Mediterranean by July 2012.

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

386

Modèle multi-échelle du transport de fluide dans un milieu poreux chargé avec échanges cationiques : application aux tissus osseux  

NASA Astrophysics Data System (ADS)

To better understand the bone diseases, many models of porous cortical bone have been developed to simulate its in vivo behaviour. Thus we proposed multiscale models including multiphysical phenomena governing the hydraulic response of bone. However, all these models neglected the possible ionic exchanges at the cellular level. Since such chemical reactions directly change the physico-chemical properties of the tissue, the interstitial flow is also modified. The aim of this study is so to include these ionic exchanges in the bone fluid transport description by deriving their consequences at the macroscale. To cite this article: J. Kaiser et al., C. R. Mecanique 337 (2009).

Kaiser, Joanna; Lemaire, Thibault; Naili, Salah; Sansalone, Vittorio

2009-11-01

387

Bruit généré par un écoulement turbulent affleurant une cavité à faible nombre de Mach : application aux césures de portes automobiles  

NASA Astrophysics Data System (ADS)

Noise produced by turbulent grazing flow over a generic cavity representing car door cavities was measured in a semi-anechoic wind tunnel. Two cavities were studied: one 50 mm large (dimension perpendicular to the airflow), functioning as a Helmholtz resonator, reaching sound pressure levels of 136 dB at 1776 Hz, for a downstream velocity of 54 m/s. The other, of scale 250 mm could not be regarded as a Helmholtz resonator although resonance occurred at 1902 Hz, at a level of 125 dB, for the same velocity. In both cases, noise was caused by Kelvin-Helmholtz instabilities in the mixing layer. To cite this article: A. Da Silva et al., C. R. Mecanique 337 (2009).

Da Silva, Arthur; Kribèche, Ali; Loredo, Alexandre

2009-02-01

388

Developpement d'une methode des caracteristiques tridimensionnelle et application aux calculs de supercellules d'un reacteur CANDU  

NASA Astrophysics Data System (ADS)

The primary purpose of this study was to construct a new method for determining the cross section increments associated with the reactivity mechanisms in CANDU reactors. Based on the characteristics method, the module MCI is successfully developed and is ready to be integrated in the lattice code DRAGON. The module MCI utilizes non cyclic tracks in a three dimensional transport calculation. The characteristics method allows to resolve the same problems as the collision probabilities method but its main advantage relies on a substantial memory economy. The results of MCI module are similar to those of an EXCELL module in the CANDU-6 calculation scheme. The characteristics method is shown to be equivalent to the collision probability method for the finite domain. A new acceleration technique, the SCR (Self-Collision Rebalancing) technique, was developed using the equivalence of these two methods. When SCR is used with the one parameter variational acceleration method, the resolution converge faster than either of the two. The Tracks Merging Technique (TMT) is a new technique developed within this research to reduce the total number of tracks needed to cover the geometry of the problem studied. The TMT can be used on two levels: TMT-1 and TMT-2. We have observed a factor of four on the reduction of tracks when the TMT was used on the first level and a factor of forty when used on the second level. The TMT could be used without difficulty in the collision probability method. The MCI module was parallelized using the PVM (Parallel Virtual Machine) library for distributed-memory environment. One of four options can be used in the parallel calculation: SPLT, ANGL, STRD and MCRB. Each of the four options is associated with a special load balancing strategy. In the first three options, the load is measured in number of tracks, in the fourth option, the load is dispatched in units of macroband.

Wu, Guang Jun

389

Présentation d’une technique 3D d’accélération de la recherche de rayons application aux télécommunications microcellulaires  

Microsoft Academic Search

Résumé  Le développement des télécommunications avec les mobiles requiert l’implantation de nombreuses stations de base (BTS) afin\\u000a de couvrir les multiples cellules constituant un réseau. Les fréquences porteuses utilisées dans les réseaux actuels (GSM,\\u000a DCS), se situent dans la gamme des hyperfréquences. Afin d’optimiser le déploiement d’un ensemble de BTS, les opérateurs souhaitent\\u000a disposer d’outils informatiques rapides et performants permettant de

Mustapha Agunaou; Michel Stanislawiak; Phillipe Mariage; Pierre Degauque

1999-01-01

390

AN EXPERIMENT IN AGRICULTURAL CREDIT: THE SMALL FARMER GROUP LENDING PROGRAMME IN GHANA (1969-1980) \\/ UN EXPERIMENT DE CREDIT AGRICOLE: LE PROGRAMME DE CREDIT AUX GROUPES DE PETITS EXPLOITANTS AGRICOLES AU GHANA (1969-1980)  

Microsoft Academic Search

Cet article analyse en détail le programme de crédit aux regroupements de petits exploitants mis en place par la Agricultural Development Bank (ADB) au Ghana dans la période 1969-1980. Avant 1969, la Banque n'avait pas réussi à actroyer du crédit aux millions de petits exploitants qui produisent la plus grande partie de l'Output agricole du pays. Á l'époque, le crédit

Kwame Opoku Owusu; William Tetteh

1982-01-01

391

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)

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 deversements non productibles dans le climat futur. Des strategies d'adaptation structurale ont ete analysees pour augmenter la capacite de production et la capacite d'ecoulement de certaines centrales hydroelectriques afin d'ameliorer la performance du systeme. Une analyse economique a permis de choisir les meilleures mesures d'adaptation et de determiner le moment opportun pour la mise en oeuvre de ces mesures. Les resultats de la recherche offrent aux gestionnaires des systemes hydriques un outil qui permet de mieux anticiper les consequences des changements climatiques sur la production hydroelectrique, incluant le rendement de centrales, les deversements non productibles et le moment le plus opportun pour inclure des modifications aux systemes hydriques. Mots-cles : systemes hydriques, adaptation aux changements climatiques, riviere Manicouagan

Haguma, Didier

392

High temperature thermoelectric properties of the type-I clathrate Ba8AuxSi46-x  

NASA Astrophysics Data System (ADS)

The thermoelectric properties of the type-I clathrate Ba8AuxSi46-x (4.10 <= x <= 6.10) were characterized from 300 to 700 K. Increasing the Au concentration leads to a transition from an n-type (x < 5.43) to a p-type (x >= 5.43) electrical conduction. The experimental data are well described by a single-parabolic-band model assuming a single scattering mechanism of the charge carriers in this temperature range. The lattice thermal conductivity, inferred from degeneracy-adjusted Lorenz numbers, is low regardless of the composition. However, the measured values are significantly lower in the p-type samples possibly due to a combination of a higher degree of disorder in the crystal structure at high Au contents and an enhanced phonon-charge carrier coupling. Even though high thermopower values are achieved, the high electrical resistivity remains the main obstacle to push the dimensionless figure of merit ZT (~0.2 at around 600 K for x = 5.59) beyond the level of the best Si-based clathrate compounds.

Candolfi, C.; Aydemir, U.; Baitinger, M.; Oeschler, N.; Steglich, F.; . Grin, Yu

2012-02-01

393

Comparative Performance of the RapID Yeast Plus System and the API 20C AUX Clinical Yeast System  

PubMed Central

The performance of the RapID Yeast Plus System (Innovative Diagnostic Systems, Norcross, Ga.), a 4-h micropanel using single-substrate enzymatic test reactions, was compared with that of the API 20C AUX Clinical Yeast System (bioMerieux Vitek, Hazelwood, Mo.), a 48- to 72-h carbohydrate assimilation panel. Two hundred twenty-five yeasts, yeast-like fungi, and algae, comprising 28 species and including 30 isolates of Cryptococcus neoformans, an important pathogen not tested in appreciable numbers in other comparisons, were tested by both methods. On initial testing, 196 (87.1%) and 215 (95.6%) isolates were correctly identified by the RapID and API systems, respectively. Upon repeat testing, the number of correctly identified isolates increased to 220 (97.8%) for the RapID system and 223 (99.1%) for the API system. Reducing the turbidity of the test inoculum to that of a no. 3 McFarland turbidity standard, which is below that recommended by the manufacturer, resulted in the correct identification of most of the isolates initially misidentified by the RapID system, including 10 of 30 C. neoformans isolates. Concordance between the RapID and API results after repeat testing was 97.3%.

Smith, Michael B.; Dunklee, Daisy; Vu, Hangna; Woods, Gail L.

1999-01-01

394

197Au and125Te Mössbauer spectroscopic study on the low temperature phases of Ag3AuX2 (X=S, Se, and Te)  

NASA Astrophysics Data System (ADS)

197Au and125Te Mössbauer spectroscopy has been applied for the low-temperature ?-phases of Ag3AuX2 (X=S, Se, and Te). The values of I. S. and Q. S. for197Au suggest that the gold atoms, linearly coordinated by two chalcogen atoms in these phases, exist as monovalent cations. The125Te Mössbauer spectra suggest that the tellurium atoms are substantially ionic for both Ag2Te and Ag3AuTe2. The nature of X-Au-X bonds is discussed on the basis of the Mössbauer data and the bond distances.

Sakai, Hiroshi; Ando, Manabu; Maeda, Yutaka

1992-04-01

395

Radiographie par rayons X à haute résolution de défauts topologiques en volume de structures modulées comparée aux neutrons en faisceau blanc  

NASA Astrophysics Data System (ADS)

Une émission de rayons X par un générateur à haute tension (plage : 50 - 410 kV) a été développée pour être utilisée avec un diffractomètre à rayons X durs et caractériser en volume des monocristaux. Le fort flux issu d'une installation de radiologie à foyer fin avec un grand pouvoir de pénétration en profondeur autorise l'étude d'échantillons très absorbants. Quelques exemples de l'utilisation de ces propriétés pour des échantillons épais et très absorbants sont présentés ; principalement l'analyse de contraintes et la topographie X projetée 2D dans des matériaux en comparaison avec l'information par la diffraction des neutrons. La diffraction à haute énergie apparaît dans la direction transmise, les angles de Bragg sont petits et ainsi les différentes lignes de réflexions sont réparties autour du faisceau principal. La presse uni-axiale utilisée pour les expériences est optimisée effectivement avec l'absence d'un bruit de fond dû à l'usage de fentes. L'optique des rayons X durs et neutrons appliquée aux échantillons épais donne une information complémentaire dans les expériences sur l'analyse de la densité volumétrique par la diffusion des rayons X et neutrons. On l'applique à des problèmes concernant des cristaux aux structures modulées étudiées sous des charges mécaniques et thermiques.

Fernandez Palacio, J.; Hamelin, B.; Marmeggi, J. C.

2004-11-01

396

Analyse quantitative des foraminifères benthiques actuels de la marge atiantique marocaine entre Cap Draˆa et Cap Juby: reponses fauniques aux changements de l'environnement  

NASA Astrophysics Data System (ADS)

La population des foraminifères benthiques actuels de la marge atlantique marocaine, entre Cap Draˆa et Cap Juby, aétéétudiée dans 58 prélèvements parmi 430 répartis suivant un système de radiales perpendiculaireàla ligne de rivage. Quarante-sept espèces parmi 104 appartenantà58 genres et 28 familles ontétéreconnues. Les abondances absolues de chacune des espèces ontétécomparées dans les différents prélèvements ainsi que les indices biocénotiques (richesse spécifique, abondance, indice de pélagisme, nombre d'espèces benthiques enroulées, nombre d'espèces benthiques costulées) et les paramètres abiotiques (nature de substrat et profondeur). L'analyse factorielle des correspond ances, complétée par la classification hiérarchique et la projection des paramètres biotiques et abiotiques en tant que colonnes supplémentaires ont révéléclue la profondeur est le facteur principal de la distribution des espèces et des prélèvements. En effet, elle oppose les associations d'espèces infralittorales enroulées lisses aux associations d'espècesépibathyales rectilignes ornées, les espèces circalittorales occupent une position intermédiaire. Le facteur secondare correspondàla nature du substrat, oppose les associations d'espèces vasicoles aux associations d'espèces sabulicoles aussi bien celles de l'environnement infralittoral que celles de l'épibathyal.

Rezqi, H.; Oujidi, M.; Boutakiout, M.; Labraimi, M.

2000-02-01

397

Endosidin1 defines a compartment involved in endocytosis of the brassinosteroid receptor BRI1 and the auxin transporters PIN2 and AUX1  

PubMed Central

Although it is known that proteins are delivered to and recycled from the plasma membrane (PM) via endosomes, the nature of the compartments and pathways responsible for cargo and vesicle sorting and cellular signaling is poorly understood. To define and dissect specific recycling pathways, chemical effectors of proteins involved in vesicle trafficking, especially through endosomes, would be invaluable. Thus, we identified chemicals affecting essential steps in PM/endosome trafficking, using the intensely localized PM transport at the tips of germinating pollen tubes. The basic mechanisms of this localized growth are likely similar to those of non-tip growing cells in seedlings. The compound endosidin 1 (ES1) interfered selectively with endocytosis in seedlings, providing a unique tool to dissect recycling pathways. ES1 treatment induced the rapid agglomeration of the auxin translocators PIN2 and AUX1 and the brassinosteroid receptor BRI1 into distinct endomembrane compartments termed “endosidin bodies”; however, the markers PIN1, PIN7, and other PM proteins were unaffected. Endosidin bodies were defined by the syntaxin SYP61 and the V-ATPase subunit VHA-a1, two trans-Golgi network (TGN)/endosomal proteins. Interestingly, brassinosteroid (BR)-induced gene expression was inhibited by ES1 and treated seedlings displayed a brassinolide (BL)-insensitive phenotype similar to a bri1 loss-of-function mutant. No effect was detected in auxin signaling. Thus, PIN2, AUX1, and BRI1 use interactive pathways involving an early SYP61/VHA-a1 endosomal compartment.

Robert, Stephanie; Chary, S. Narasimha; Drakakaki, Georgia; Li, Shundai; Yang, Zhenbiao; Raikhel, Natasha V.; Hicks, Glenn R.

2008-01-01

398

Application of the Rotating Flighted Cylinder to Livestock Waste Management.  

National Technical Information Service (NTIS)

The rotating flighted cylinder was tested as both a solid-liquid separator and as a biological waste treatment device. As a solid-liquid separator, it was demonstrated to be effective in removing settleable particles from a dilute slurry and concentrating...

J. R. Miner W. E. Verley

1975-01-01

399

Communication presentee aux \\  

Microsoft Academic Search

This paper will present salient findings of a 5 year doctoral research on criminal career development among Maltese male youth. Although the original work addressed various aspects of criminal career development, this paper will highlight those aspects of the research findings that throw light on social exclusionary processes in Maltese society that contribute to criminality. The paper explores the criminal

Marilyn Clark

400

Rayleigh-Taylor stability boundary at solid-liquid interfaces.  

PubMed

A previous model for the Rayleigh-Taylor instability [A. R. Piriz, J. J. López Cela, and N. A. Tahir, Phys. Rev. E 80, 046305 (2009)] has been extended in order to study an interface between an elastic-plastic solid and a Newtonian liquid and determine the stability region given by the initial perturbation amplitude ?(0) and wavelength ?. The stability region is found to be enhanced by the effect of the liquid viscosity, but it reaches an asymptote for a sufficiently high viscosity. In addition, it is also found that the boundary for the transition from the elastic to the plastic regime get closer to the stability boundary up to both boundaries coincide for a high enough liquid viscosity, thus making the onset of plastic flow a sufficient condition for instability. PMID:24032942

Piriz, A R; Sun, Y B; Tahir, N A

2013-08-01

401

Atomic Resolution Images of Solid-Liquid Interfaces  

NASA Astrophysics Data System (ADS)

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.

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

402

Intermetallic phase formation in thin solid-liquid diffusion couples  

SciTech Connect

Conducting joints with low fabrication temperatures and high thermal stability are useful in modern electronics. This paper discusses the potential use of intermetallic phases in making such joints. Thin interconnection layers that consist entirely of intermetallic phases have been produced by joining planar Cu substrates that are coated with thin films of Sn. Thin layers (1-5 {mu}m) of intermetallic phases are produced at temperatures slightly above the melting temperature of Sn in a process similar to reflow soldering. Metallography and x-ray analysis are used to characterize the formation mechanism of the intermetallic. Cu dissolves into the liquid Sn by diffusion along narrow channels between grains of the growing {eta}-Cu{sub 6}Sn{sub 5} intermetallic phase. tensile tests were used to measure mechanical properties. The joint strength increased with reaction time. The joint fails in a ductile mode as long as unreacted Sn is present, but fractures along interphase boundaries when the joint is completely intermetallic. 6 refs., 5 figs.

Bartels, F.; Morris, J.W. Jr. [Lawrence Berkeley Lab., CA (United States); Dalke, G.; Gust, W. [Max-Planck-Institut fuer Metallforschung, Stuttgart (Germany)

1994-08-01

403

Solid-liquid iron partitioning in Earth's deep mantle.  

PubMed

Melting processes in the deep mantle have important implications for the origin of the deep-derived plumes believed to feed hotspot volcanoes such as those in Hawaii. They also provide insight into how the mantle has evolved, geochemically and dynamically, since the formation of Earth. Melt production in the shallow mantle is quite well understood, but deeper melting near the core-mantle boundary remains controversial. Modelling the dynamic behaviour of deep, partially molten mantle requires knowledge of the density contrast between solid and melt fractions. Although both positive and negative melt buoyancies can produce major chemical segregation between different geochemical reservoirs, each type of buoyancy yields drastically different geodynamical models. Ascent or descent of liquids in a partially molten deep mantle should contribute to surface volcanism or production of a deep magma ocean, respectively. We investigated phase relations in a partially molten chondritic-type material under deep-mantle conditions. Here we show that the iron partition coefficient between aluminium-bearing (Mg,Fe)SiO(3) perovskite and liquid is between 0.45 and 0.6, so iron is not as incompatible with deep-mantle minerals as has been reported previously. Calculated solid and melt density contrasts suggest that melt generated at the core-mantle boundary should be buoyant, and hence should segregate upwards. In the framework of the magma oceans induced by large meteoritic impacts on early Earth, our results imply that the magma crystallization should push the liquids towards the surface and form a deep solid residue depleted in incompatible elements. PMID:22810700

Andrault, Denis; Petitgirard, Sylvain; Lo Nigro, Giacomo; Devidal, Jean-Luc; Veronesi, Giulia; Garbarino, Gaston; Mezouar, Mohamed

2012-07-19

404

Solid-liquid iron partitioning in Earth's deep mantle  

NASA Astrophysics Data System (ADS)

Melting processes in the deep mantle have important implications for the origin of the deep-derived plumes believed to feed hotspot volcanoes such as those in Hawaii (1). They also provide insight into how the mantle has evolved, geochemically and dynamically, since the formation of Earth (2). Melt production in the shallow mantle is quite well understood, but deeper melting near the core-mantle boundary remains controversial. Modelling the dynamic behaviour of deep, partially molten mantle requires knowledge of the density contrast between solid and melt fractions. Although both positive and negative melt buoyancies can produce major chemical segregation between different geochemical reservoirs, each type of buoyancy yields drastically different geodynamical models. Ascent or descent of liquids in a partially molten deep mantle should contribute to surface volcanismor production of a deep magma ocean, respectively. We investigated phase relations in a partially molten chondritic-type material under deep-mantle conditions. Here we show that the iron partition coefficient between aluminium-bearing (Mg,Fe)SiO3 perovskite and liquid is between 0.45 and 0.6, so iron is not as incompatible with deep-mantle minerals as has been reported previously (3). Calculated solid and melt density contrasts suggest that melt generated at the core-mantle boundary should be buoyant, and hence should segregate upwards. In the framework of the magma oceans induced by large meteoritic impacts on early Earth, our results imply that the magma crystallization should push the liquids towards the surface and form a deep solid residue depleted in incompatible elements. (1) Lay et al. (2004) Phys. Earth Planet. Inter. 146, 441-467. (2) Solomatov (2000) in Origin of the Earth and Moon, 323-338, Univ. Arizona Press. (3) Nomura et al. (2011) Nature 473, 199-202 (2011).ressure evolution of the Fe-partition coefficient between silicate melt and the Mg-Pv liquidus phase. It is determined using XRF (Red circles) and EPMA (red square) analyses of this study. We report the recent results obtained after melting of olivine (Green circles, ref. 3). The coloured diamonds correspond to previous data sets obtained using the large volume press.

Andrault, D.; Petitgirard, S.; Lo Nigro, G.; Devidal, J.; Veronesi, G.; Garbarino, G.; Mezouar, M.

2012-12-01

405

Direct simulation of flows of solid-liquid mixtures  

Microsoft Academic Search

A finite element technique based on moving unstructured grids is developed to simulate the motion of a large number of solid particles in a flowing liquid. A generalized Galerkin finite element formulation which incorporates both the fluid and particle equations of motion into a single variational equation is developed for Newtonian fluids. The hydrodynamic forces and moments acting on the

H. H. Hu

1996-01-01

406

Aqueous Surfactant Self-Assembly at Solid-Liquid Interfaces  

NASA Astrophysics Data System (ADS)

We conducted a series of experimental adsorption isotherms for aqueous non-ionic (C12E6) and ionic (CTAB) surfactants on Au (hydrophobic), SiO2 (partially hydrophilic), and Al2O3 (hydrophilic) surfaces at room temperature. The amount of surfactant adsorbed per unit surface area was measured as a function of the surfactant bulk concentration by means of a Quartz Crystal Microbalance. To assess the equilibrium adsorbed structures we conducted all-atom molecular dynamics (MD) simulations for surfactants at the water-graphite and water-SiO2 interfaces. The results not only provide a molecular interpretation for the experimental data, but also allow us to identify the driving forces responsible for the surfactant self-assembly. For example, our MD calculations predict that SDS form hemicylindrical structures at water-graphite interfaces, in agreement with solution AFM studies (Wanless and Ducker, JPC 100, 1996, 3207). By conducting test simulations for SDS-like surfactants in which we suppressed surfactant head -- counter ion electrostatic interactions we proved that the hemicylindrical structure forms because of the condensation of counter ions near the hydrophilic SDS surfactant heads.

Striolo, Alberto; Tummala, Nage Rajesh; Gutig, Camille; Grady, Brian

2007-03-01

407

Complete statistical thermodynamics of the cluster solid-liquid transition  

Microsoft Academic Search

A constant (N,P,T) statistical method is developed for a finite-size system. A scaling variable a is introduced to describe the size of the system following the method used for the bulk system. The histograms of the Boltzmann distribution function f(Ec,V;T,P) (Ec and V being the configuration energy and the volume) for a 55-atom cluster bound by Lennard-Jones pair potentials are

Hai-Ping Cheng; Xiuling Li; Robert L. Whetten; R. S. Berry

1992-01-01

408

Rayleigh-Taylor stability boundary at solid-liquid interfaces  

NASA Astrophysics Data System (ADS)

A previous model for the Rayleigh-Taylor instability [A. R. Piriz, J. J. López Cela, and N. A. Tahir, Phys. Rev. EPLEEE81539-375510.1103/PhysRevE.80.046305 80, 046305 (2009)] has been extended in order to study an interface between an elastic-plastic solid and a Newtonian liquid and determine the stability region given by the initial perturbation amplitude ?0 and wavelength ?. The stability region is found to be enhanced by the effect of the liquid viscosity, but it reaches an asymptote for a sufficiently high viscosity. In addition, it is also found that the boundary for the transition from the elastic to the plastic regime get closer to the stability boundary up to both boundaries coincide for a high enough liquid viscosity, thus making the onset of plastic flow a sufficient condition for instability.

Piriz, A. R.; Sun, Y. B.; Tahir, N. A.

2013-08-01

409

Relation between anomalous Hall effect and the Dzaloshisky-Moriya anisotropy in the series of (Ag1-xAux)0.9Mn0.1 alloys  

NASA Astrophysics Data System (ADS)

The influence of the Dzyaloshinsky-Moriya (DM) anisotropy on Rs??ex/M, where ?ex is the extraordinary Hall resistivity and M is the magnetization, is investigated in canonical spin glass (SG) alloys. The strength of the DM anisotropy in the alloys is changed systematically by doping the third non-magnetic impurities. The Hall resistivity ?H, the magnetization M and the resistivity ? were measured in the series of (Ag1-xAux)0.9Mn0.1 alloys with x=0, 0.007, 0.03, and 0.05. The difference between the values of zero field cooled and field cooled Rs, below the SG transition temperature, clearly increased with the amount of Au impurities. The dependence of the chirality contribution to Rs on the DM anisotropy is discussed in relation to the theoretical work for the chirality-driven anomalous Hall effect in weak coupling regime.

Yamanaka, K.; Taniguchi, T.; Yamazaki, T.; Ashitaka, N.; Morimoto, Y.; Tabata, Y.; Kawarazaki, S.

2007-03-01

410

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)

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.

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

411

Low-temperature thermoelectric, galvanomagnetic, and thermodynamic properties of the type-I clathrate Ba8AuxSi46-x  

NASA Astrophysics Data System (ADS)

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.

Aydemir, U.; Candolfi, C.; Ormeci, A.; Oztan, Y.; Baitinger, M.; Oeschler, N.; Steglich, F.; Grin, Yu.

2011-11-01

412

Travailleurs âgés, nouvelles technologies et changements organisationnels : un réexamen à partir de l'enquête « Reponse ». Suivi d'un commentaire de Luc Behaghel : emploi des seniors - Des effets du changement technologique aux recommandations  

Microsoft Academic Search

[fre] L'adoption par les entreprises d'innovations technologiques (micro-ordinateur, internet), de changements organisationnels ou leur ouverture au marché international posent la question de l'adaptation des travailleurs âgés (seniors) : les entreprises concernées évincent-elles plus souvent ou non les seniors de leur main-d'oeuvre ? L'analyse du stock d'emploi en 1998 confirme l'hypothèse d'un biais de ces changements défavorable aux seniors. Dans l'industrie

Patrick Aubert; Luc Behaghel; Sévane Ananian

2006-01-01

413

DET/MPS - THE GSFC ENERGY BALANCE PROGRAM, DIRECT ENERGY TRANSFER/MULTIMISSION SPACECRAFT MODULAR POWER SYSTEM (MACINTOSH A/UX VERSION)  

NASA Technical Reports Server (NTRS)

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 registered trademark of AT&T Bell Laboratories.

Jagielski, J. M.

1994-01-01

414

A single coil radio frequency gradient probe for nuclear magnetic resonance applications.  

PubMed

A single coil nuclear magnetic resonance (NMR) probehead and associated electronics capable of asynchronously applying both homogeneous and inhomogeneous radio frequency (rf) pulses to solid, liquid, or gaseous samples is described. This equipment can be interfaced with a conventional single channel NMR spectrometer. Carefully placed PIN diodes on the NMR probehead are used to switch the coil between a homogeneous end tapped configuration and an inhomogeneous center tapped rf gradient configuration. This approach dramatically improves channel isolation in comparison to existing two coil designs. Descriptions of the new probehead, the transistor-transistor logic (TTL) controlled dc pulser for PIN diode gating, and the high power rf switch are provided. Several NMR pulse sequences are used to test the channel isolation and probe performance. Finally an application to liquid phase solvent suppression is provided. PMID:23278008

Christofield, N; Sobieski, D N; Erker, J C; May, S; Augustine, M P

2012-12-01

415

Flight Test Technique Series - Volume 15. Introduction to Avionics Flight Test (Introduction aux Essais des Systemes D'armes).  

National Technical Information Service (NTIS)

This case study has demonstrated a couple of important points. First, the simple techniques described in the previous sections are useful for real world application and are adequate for a wide range of quick measurements. What some of the tests lack in pr...

J. M. Clifton

1996-01-01

416

Loi n o 2005-370 du 22 avril 2005 relative aux droits des malades et à la fin de vie : application à un cas de polytraumatisme  

Microsoft Academic Search

The law number 2005-370 of April 22, 2005 concerning the patients’ rights at the end of life imposes from now the refusal of futility of care, a shared decision-making in unconscious patients and the duty of a palliative strategy. We describe a case of polytrauma, for which the shared decision-making process led to a palliative strategy after initial aggressive life-support

K. Chedevergne; F. Cook; E. Scherrer; J. Marty; E. Ferrand

2008-01-01

417

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)

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

Mora, Brice

418

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

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.

Chou, I. -M.; Sterner, S. M.; Pitzer, K. S.

1992-01-01

419

Generation d'impulsions breves utilisant la non-linearite associee aux porteurs de charge libres dans des semi-conducteurs  

NASA Astrophysics Data System (ADS)

Dans cette these, nous utilisons la non-linearite associee aux porteurs de charge libres generes par absorption multi-photonique dans des semi-conducteurs pour produire des impulsions breves dans l'infrarouge moyen. Nous proposons d'abord la methode de generation par suppression de la transmission et auto-defocalisation, ou le faisceau incident a l'angle de Brewster genere les porteurs de charge libres, creant un profil d'indice qui defocalise le faisceau. L'impulsion resultante presente un temps de montee calque sur l'impulsion initiale, suivie d'une coupure abrupte. En polarisation TE, on obtient le decoupage par effet d'etalon ou le faisceau est incident sur un etalon oriente sur un minimum de transmission; le debut de l'impulsion est reflechi. Le changement d'indice accompagnant la creation de porteurs de charge libres syntonise la transmission de l'etalon et seule la partie centrale de l'impulsion est transmise. Enfin, le decoupage peut aussi s'effectuer en configuration pompe-sonde; un faisceau continu (sonde) est incident sur un etalon simultanement soumis a l'illumination d'une d'impulsion breve (pompe). Cette derniere genere des porteurs de charge libres, conduisant a un glissement de la frequence instantanee de la sonde. Le faisceau est envoye dans un filtre spectral qui ne transmet que la portion ayant subi un important glissement de frequence.

Richard, Isabelle

420

The auxin influx carriers AUX1 and LAX3 are involved in auxin-ethylene interactions during apical hook development in Arabidopsis thaliana seedlings.  

PubMed

Dark-grown dicotyledonous seedlings form a hook-like structure at the top of the hypocotyl, which is controlled by the hormones auxin and ethylene. Hook formation is dependent on an auxin signal gradient, whereas hook exaggeration is part of the triple response provoked by ethylene in dark-grown Arabidopsis seedlings. Several other hormones and light are also known to be involved in hook development, but the molecular mechanisms that lead to the initial installation of an auxin gradient are still poorly understood. In this study, we aimed to unravel the cross-talk between auxin and ethylene in the apical hook. Auxin measurements, the expression pattern of the auxin reporter DR5::GUS and the localization of auxin biosynthesis enzymes and influx carriers collectively indicate the necessity for auxin biosynthesis and efficient auxin translocation from the cotyledons and meristem into the hypocotyl in order to support proper hook development. Auxin accumulation in the meristem and cotyledons and in the hypocotyl is increased approximately 2-fold upon treatment with ethylene. In addition, a strong ethylene signal leads to enhanced auxin biosynthesis at the inner side of the hook. Finally, mutant analysis demonstrates that the auxin influx carrier LAX3 is indispensable for proper hook formation, whereas the auxin influx carrier AUX1 is involved in the hook exaggeration phenotype induced by ethylene. PMID:20110325

Vandenbussche, Filip; Petrásek, Jan; Zádníková, Petra; Hoyerová, Klára; Pesek, Bedrich; Raz, Vered; Swarup, Ranjan; Bennett, Malcolm; Zazímalová, Eva; Benková, Eva; Van Der Straeten, Dominique

2010-02-01

421

Applications of Environmental Biotechnology  

Microsoft Academic Search

\\u000a Environmental biotechnology is a system of scientific and engineering knowledge related to the use of microorganisms and their\\u000a products in the prevention of environmental pollution through biotreatment of solid, liquid, and gaseous wastes, bioremediation\\u000a of polluted environments, and biomonitoring of environment and treatment processes. The advantages of biotechnological treatment\\u000a of wastes are as follows: biodegradation or detoxication of a wide

Volodymyr Ivanov; Yung-Tse Hung

422

Recent advances in vacuum sciences and applications  

NASA Astrophysics Data System (ADS)

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.

Mozeti?, 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.; Radi?, N.; Draži?, G.; Bernstorff, S.; Biederman, H.; Kylián, O.; Hanuš, J.; Miloševi?, S.; Galtayries, A.; Dietrich, P.; Unger, W.; Lehocky, M.; Sedlarik, V.; Stana-Kleinschek, K.; Drmota-Petri?, A.; Pireaux, J. J.; Rogers, J. W.; Anderle, M.

2014-04-01

423

Application of electro acoustics for dewatering pharmaceutical sludge  

SciTech Connect

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.

Golla, P.S.; Johnson, H.W. (Ashbrook-Simon-Hartley, Houston, TX (United States)) Senthilnathan, P.R. (Zenon Environmental Inc., Burlington, Ontario (Canada))

1992-02-01

424

Cartographie de l'elevation de l'interface eau douce-eau salee aux iles-de-la-madeleine par la methode electromagnetique transitoire (TEM)  

NASA Astrophysics Data System (ADS)

This research project is dedicated to mapping the elevation of the freshwater-saltwater interface in Magdalen Islands using the transient electromagnetic method (TEM) in order to monitor time-varying quality of groundwater tables. Seventy-three TEM soundings were conducted between May 2010 and June 2011 close to Well regions in Fatima, Étang-du-Nord, Havre-Aux-Maisons, Grande-Entrée and Grosse-Île. TEM soundings were carried out with loops of 50 m x 50 m and 60 m x 40 m x 2 turns except some surveys of 100 m x 100 m. To control water quality and help constrain the interpretation of TEM soundings, conductivity logs were made in four previous exploration wells and fifteen wells drilled in 2009. Results show that saline water is associated with a low resistivity level between 2 and 4 ?.m and its elevation ranges from -40 m at Grand-Entrée and more than -250 m at Havre-Aubert. In Étang-du-Nord east, Fatima east and Grande-Entrée, saline water is shallow near shore and plunges inward as expected by the Ghyben Herzberg relation. These three areas have been identified to achieve the time-lapse monitoring of groundwater because of the risk associated with the proximity of wells in operation and the low elevation of saline water. Fatima center area close to FAT03 and FAT07 soundings and Havre-Aux-Maisons showed inconsistent results with the hydrogeological model, further work is recommended to verify the origin of the conductive areas highlighted. However, the results of the interpretation of areas at Havre-Aubert and Grosse-Île did not show a risk of contamination due to the depth of saline water. Modeling of the transition zone between the freshwater aquifer and the saline groundwater has demonstrated that it was difficult to solve it for thicknesses below 10 m and 30 m to depths of 40 and 130 m respectively. If the resistivity of the transition zone is known, the resolution is improved (5 and 10 m respectively). TEM soundings showed negative responses at late time associated with induced polarization (IP) effects. The inversion results of TEM soundings affected by this effect have shown that this dispersion most likely originates from near-surface layers. Chargeabilities ranging from 0.8 to 0.9 were obtained on the TEM soundings processed. The origin of this chargeability is currently unknown but could be related to the presence of fine material (clay). IP effect has not prevented determination of the saline water to a maximum depth of 250 m. The laboratory tests on core samples were unfortunately not able to determine the relationship between resistivity and water resistivity of saturated red sandstone. Immersion of cores in deionized water failed to eliminate the salt present in it. For time-varying monitoring of groundwater, we recommend performing drilling through the interface between freshwater and saltwater on selected areas, to conduct conductivity logs to fully characterize the level of this interface, to install multiparameter probes (conductivity, temperature, pressure) in monitoring wells located at different levels and to locate sites of TEM soundings in the vicinity that will be used to monitor the groundwater.

Madani, Abdelhamid

425

Transposition des processus membranaires biologiques aux traitements des effluents métallifères peu chargés. Conception et étude chimique d'une pompe ionique uranifère. Transport, contre-transport, couplage positif  

NASA Astrophysics Data System (ADS)

An ionic pump has been devided thanks to au “liquid-liquid" extraction-reextration where the extraction compartment and the reextraction compartment are put in contact with one another through the membrane composed of an mediator diluted in the kerosene. We have applied this process to the system: uranyle nitrate, nitric acid-phosphate tributyle, kerosene-sodium carbonate. Interesting performances have been realised for diluted solutions (100 ppm). The chemicals parameters has allowed to obtain the variables giving the extraction and reextraction efficiency optimum. A chemical modelisation has allowed to identify the extraction mechanism. The classical behaviour obtained in agitated surroundings has been found again. The membrane can work thanks to the “activation" by the solute of the carrier at one interface and to the “deactivation" at the other interface, both of these mechanisms of the active transport creating a real “ionic pumping". Une pompe ionique est mise au point grâce à une ensemble “extraction-réextraction" “liquide-liquide" où le compartiment extraction et le compartiment réextraction sont mis en contact par l'intermédiaire d'une membrane contenant un transporteur dilué dans le kérosène. Ce procédé est appliqué aux ions uranyles. Des rendements intéressants sont obtenus pour des solutions diluées (100 ppm). L'étude des variables a permis de déterminer des paramètres chimiques donnant des rendements d'extraction et de réextration optimum. Le comportement symétrique des deux compartiments montre que nous avons un transport, contre-transport, couplage positif. Une modélisation chimique a permis d'identifier les mécanismes d'extraction. Le comportement classique obtenu en milieu agité est retrouvé. La pompe peut fonctionner grâce à l'activation du transporteur par le cosoluté contenu dans le compartiment d'extraction et à la désactivation à la sortie de la membrane par le cosoluté contenu dans le compartiment réextraction créant un pompage ionique.

Hasaine-Sadi, F.; Benhassaine, A.; Ait-Amar, H.

1999-09-01

426

Size and concentration effects in the optical properties of alloyed (AuxAg1 - x)n and core-shell (NixAg1 - x)n embedded clusters  

NASA Astrophysics Data System (ADS)

Optical properties of mixed clusters (AuxAg 1 - x)n and (NixAg 1 - x)n, produced by laser vaporization and embedded in an alumina matrix, are reported. The size effects are investigated for different concentrations (x = 0.25, 0.5 and 0.75) in the diameter range 2-4 nm. For alloyed clusters (AuxAg 1 - x)n of a given size an almost linear evolution of the surface plasmon frequency ?s with the concentration is observed (between those of pure gold and pure silver clusters). Moreover the blue-shift and the damping of the resonance with decreasing size is all the more important as the gold concentration in the particles increases. Such results are in agreement with theoretical calculations carried out in the frame of the time-dependent local-density-approximation (TDLDA) including an inner skin of ineffective screening and the porosity of the matrix. The optical response of (NixAg 1 - x)n clusters exhibits a surface plasmon resonance in the same spectral range as the one observed for pure silver clusters, but considerably damped and broadened. For a given mean cluster size 3.0 nm, a blue-shift of the resonance is observed when increasing the nickel concentration (between x = 0.25 and x = 0.75). The results are in good qualitative agreement with classical predictions in the dipolar approximation, assuming a core-shell geometry.

Gaudry, M.; Lermé, J.; Cottancin, E.; Pellarin, M.; Prével, B.; Treilleux, M.; Mélinon, P.; Rousset, J.-L.; Broyer, M.

427

Predictions with UNIFAC of liquid-solid phase diagrams: application to water-sucrose-glucose, water-sucrose-fructose and water-xylose-mannose  

NASA Astrophysics Data System (ADS)

The objective of this study is to develop a prediction model of solid-liquid equilibria based on the UNIFAC method which is applicable to sugar systems. Three new groups, X, F and G, representing respectively the cyclic structure of D-xylose, D-fructose and D-glucose are introduced and new interaction parameters for these groups are calculated. The use of groups X, F and G permits the identification of mannose as composed of X, OH and CH 2 and of sucrose as composed of G, F and -O-. The model is tested on three ternary systems: water-sucrose-D-glucose; water-sucrose-D-fructose; water-D-xylose-D-mannose. The results compare favourably with the experimental data except in the invariant point region, corresponding to saturation with both solutes. A similar technique could be applied in the prediction of the behaviour of other sugar systems containing these basic rings.

Gabas, N.; Laguérie, C.

1993-03-01

428

Une introduction aux subventions intergouvernementales  

Microsoft Academic Search

The principal aim of our paper is to provide a primer on the foundations of the theory of intergovernmental grants, suitable for newcomers to this active field of research. In addition, we provide a selective survey of recent theoretical papers on grants, focusing particularly on non-cooperative games between different levels of government in a federal system. The sections of the

Tracy Snoddon; Jean-François Wen

1999-01-01

429

Coordination polymer gels with important environmental and biological applications.  

PubMed

Coordination Polymer Gels (CPGs) constitute a subset of solid-like metal ion and bridging organic ligand structures (similar to metal-organic frameworks) that form multi-dimensional networks through a trapped solvent as a result of non-covalent interactions. While physical properties of these gels are similar to conventional high molecular weight organic polymer gels, coordination polymer gel systems are often fully reversible and can be assembled and disassembled in the presence of additional energy (heat, sonication, shaking) to give a solution of solvated gelators. Compared to gels resulting from purely organic self-assembled low molecular weight gelators, metal ions incorporated into the fibrilar networks spanning the bulk solvent can impart CPGs with added functionalities. The solid/liquid nature of the gels allows for species to migrate through the gel system and interact with metals, ligands, and the solvent. Chemosensing, catalysis, fluorescence, and drug-delivery applications are some of the many potential uses for these dynamic systems, taking advantage of the metal ion's coordination, the organic polydentate ligand's orientation and functionality, or a combination of these properties. By fine tuning these systems through metal ion and ligand selection and by directing self-assembly with external stimuli the rational synthesis of practical systems can be envisaged. PMID:23192282

Jung, Jong Hwa; Lee, Ji Ha; Silverman, Julian R; John, George

2013-02-01

430