Modeling of elastic properties of charge stabilized colloidal crystals with body-centered cubic lattice

Elastic properties of charge stabilized colloidal crystals of charged spherical particles with monatomic body-centered cubic crystal lattice are studied numerically. The model of the crystals is based on the nonlinear differential Poisson-Boltzmann equation. Elastic constants of the crystals are derived from the stress-strain dependencies obtained by means of computer experiment. Stability of the crystals and the presence of many-body effective interactions in them are briefly discussed

Efficient simulations of charged colloidal dispersions: A density functional approach

A numerical method is presented for first-principle simulations of charged colloidal dispersions in electrolyte solutions. Utilizing a smoothed profile for colloid-solvent boundaries, efficient mesoscopic simulations are enabled for modeling dispersions of many colloidal particles exhibiting many-body electrostatic interactions. The validity of the method was examined for simple colloid geometries, and the efficiency was demonstrated by calculating stable structures of two-dimensional dispersions, which resulted in the formation of colloidal crystals.Comment: 6 pages, 4 figure

Explicit finite-difference and direct-simulation-MonteCarlo method for the dynamics of mixed Bose-condensate and cold-atom clouds

We present a new numerical method for studying the dynamics of quantum fluids composed of a Bose-Einstein condensate and a cloud of bosonic or fermionic atoms in a mean-field approximation. It combines an explicit time-marching algorithm, previously developed for Bose-Einstein condensates in a harmonic or optical-lattice potential, with a particle-in-cell MonteCarlo approach to the equation of motion for the one-body Wigner distribution function in the cold-atom cloud. The method is tested against known analytical results on the free expansion of a fermion cloud from a cylindrical harmonic trap and is validated by examining how the expansion of the fermionic cloud is affected by the simultaneous expansion of a condensate. We then present wholly original calculations on a condensate and a thermal cloud inside a harmonic well and a superposed optical lattice, by addressing the free expansion of the two components and their oscillations under an applied harmonic force. These results are discussed in the light of relevant theories and experiments.Comment: 33 pages, 13 figures, 1 tabl

Comparison of Physical-chemical and Mechanical Properties of Chlorapatite and Hydroxyapatite Plasma Sprayed Coatings

Chlorapatite can be considered a potential biomaterial for orthopaedic applications. Its use as plasma-sprayed coating could be of interest considering its thermal properties and particularly its ability to melt without decomposition unlike hydroxyapatite. Chlorapatite (ClA) was synthesized by a high-temperature ion exchange reaction starting from commercial stoichiometric hydroxyapatites (HA). The ClA powder showed similar characteristics as the original industrial HA powder, and was obtained in the monoclinic form. The HA and ClA powders were plasma-sprayed using a low-energy plasma spraying system with identical processing parameters. The coatings were characterized by physical-chemical methods, i.e. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy, including distribution mapping of the main phases detected such as amorphous calcium phosphate (ACP), oxyapatite (OA), and HA or ClA. The unexpected formation of oxyapatite in ClA coatings was assigned to a side reaction with contaminating oxygenated species (O2, H2O). ClA coatings exhibited characteristics different from HA, showing a lower content of oxyapatite and amorphous phase. Although their adhesion strength was found to be lower than that of HA coatings, their application could be an interesting alternative, offering, in particular, a larger range of spraying conditions without formation of massive impurities.This study was carried out under a MNT ERA-Net Project named NANOMED. The authors gratefully thank the Midi-Pyrénées region (MNT ERA Net Midi-Pyrénées Région, NANOMED2 project) and the Institute National Polytechnique de Toulouse (BQR INPT 2011, BIOREVE project) for supporting this research work, especially the financial support for research carried out in the CIRIMAT and the LGP laboratories (France), and the Basque government and Tratamientos Superficiales Iontech, S.A. for their financial and technical support under the IG-2007/0000381 grant for the development of the LEPS device and deposition of the coatings carried out in Inasmet-Tecnalia. The French industrial collaborators (TEKNIMED SA and 2PS SA) were financed by the OSEO programs

Modélisation des procédés de projection plasma et de traitement laser d'hydroxyapatite

LILLE1-BU (590092102) / SudocSudocFranceF

Selective Oxidation of Methacrolein to Methacrylic Acid: the SOMMA Project

International audienc

Experimental investigation of influence of plasma spraying operational parameters on properties of hydroxyapatite

ora

Module porte-échantillons destiné au traitement thermique de matériaux solides

The invention relates to a sample holder module (3, 100) intended to be placed in a furnace (2) within the context of a heat treatment of solid materials. The main feature of a heat treatment system according to the invention is that it comprises at least two housings (17, 19, 117, 119) each suitable for receiving a sample of solid material to be treated, and in that it comprises a common gas inlet (12) equipped with a distribution element (31) that makes it possible to convey the gas individually to each housing (17, 19, 117, 119), a common gas outlet (13) for gas originating from said housings (17, 19) and elements (29, 129) for regulating the gas stream that each connect the distribution element (31) to a housing (17, 19, 117, 119) in order to enable each of said housings to receive the same flow rate of gas.L'invention se rapporte à un module (3, 100) porte-échantillons, destiné à être placé dans un four (2) dans le cadre d'un traitement thermique de matériaux solides. La principale caractéristique d'un système de traitement thermique selon l'invention, est qu'il comprend au moins deux logements (17, 19, 117, 119) aptes à recevoir chacun un échantillon de matériau solide à traiter, et en ce qu'il comprend une arrivée de gaz (12) commune équipée d'un élément de distribution (31) permettant d'acheminer le gaz individuellement vers chaque logement (17, 19, 117, 119), une sortie de gaz commune (13) en provenance desdits logements (17, 19) et des éléments de régulation (29, 129) de flux gazeux reliant chacun l'élément de distribution (31) à un logement (17, 19, 117, 119) pour permettre à chacun desdits logements de recevoir le même débit de gaz

Highthrouhput approach for optimizing three-way-catalyst for natural gas engine : importance of the metal-support interface

International audienc