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Interface Region (interface + region)
Selected AbstractsLevel-set based numerical simulation of a migrating and dissolving liquid drop in a cylindrical cavityINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 4 2004Edmondo Bassano Abstract In the present paper the dissolution of a binary liquid drop having a miscibility gap and migrating due to thermo-solutal capillary convection in a cylindrical cavity is studied numerically. The interest in studying this problem is twofold. From a side, in the absence of gravity, capillary migration is one of the main physical mechanisms to set into motion dispersed liquid phases and from the other side, phase equilibria of multi-component liquid systems, ubiquitous in applications, often exhibit a miscibility gap. The drop capillary migration is due to an imposed temperature gradient between the cavity top and bottom walls. The drop dissolution is due to the fact that initial composition and volume values, and thermal boundary conditions are only compatible with a final single phase equilibrium state. In order to study the drop migration along the cavity and the coupling with dissolution, a previously developed planar two-dimensional code is extended to treat axis-symmetric geometries. The code is based on a finite volume formulation. A level-set technique is used for describing the dynamics of the interface separating the different phases and for mollifying the interface discontinuities between them. The level-set related tools of redistancing and off-interface extension are used to enhance code resolution in the critical interface region. Migration speeds and volume variations are determined for different drop radii. Copyright © 2004 John Wiley & Sons, Ltd. [source] Freezing time calculations for various productsINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 12 2003Esmail M. A. Mokheimer Abstract This article presents a numerical simulation that estimates the freezing time for different products. In this regard, the freezing process is mathematically modelled by transient heat conduction equations that incorporate the physical properties of the three distinct regions that exist during a freezing process. These regions are namely, the solid phase region, the liquid phase region and the interface region. This model is experimentally validated and used to estimate the freezing time for three different food products, which are namely, fish balls, cherry juice and peas balls. The freezing times estimated numerically through the present model agree well with those reported in the literature and are in excellent agreement with the experimental data. Copyright © 2003 John Wiley & Sons, Ltd. [source] Solvation of acylium fragment ions in electrospray ionization quadrupole ion trap and Fourier transform ion cyclotron resonance mass spectrometryJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 3 2001Ziqiang Guan Abstract In electrospray ionization (ESI) quadrupole ion trap and Fourier transform ion cyclotron resonance mass spectrometry, certain fragment ions (e.g. acylium ions) generated either during the ion transportation process (in the source interface region) or in the ion trap are found to undergo ion,molecule reactions with ESI solvent molecules (water, acetonitrile and aliphatic alcohols) to form adduct species. These unexpected solvated fragment ions severely complicate the interpretation of mass spectrometic data. High-resolution accurate mass measurements are important in establishing the elemental compositions of these adduct species and preventing erroneous data interpretation. Copyright © 2001 John Wiley & Sons, Ltd. [source] Thermal Stability of a Chemically Vapor Deposited Multilayer Coating Containing Amorphous Silica and Rutile Titania on Hi-Nicalon FiberJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 10 2003Jinil Lee A multilayer coating consisting of consecutive layers of amorphous-silica, rutile-titania, and amorphous-silica was prepared on Hi-Nicalon fiber by chemical vapor deposition at 1050°C. It appeared that the silica and titania layers were strongly bonded to each other with no evidence of detachment and crack deflection at the interface region. The layered structure became morphologically unstable because of the growth of titania grains, the crystallization of the silica layers, and the oxidation of the fiber on exposure to 1200°C in air for 92 h. [source] Photoluminescence depth-profiling of lattice-mismatched InGaN thick film on GaN using inductively coupled plasma etchingPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2006Ji-Myon Lee Abstract Photoluminescence depth profiling of highly strained In0.1Ga0.9N and In0.15Ga0.85N epitaxial films have been studied employing an inductively coupled Cl2 plasma etching. The photoluminescence measurements showed that thick InGaN films (0.2 ,m) consist of three different structural phases; (i) an InN-rich region near the InGaN film surface, (ii) a region that was free from InN-rich phase under stress-relaxation in the middle of the film, and (iii) an InGaN/GaN interface region. In region (i), a higher wavelength peak from the InN-rich phase was dominant. After removing the surface layer of 500 Å, the PL peaks from InN-rich phases completely disappeared, suggesting that the InN-rich phase region is confined to a depth of 500 Å. In regions of (ii) and (iii), the strain-relaxation between InGaN and GaN had a significant influence on the luminescence properties of InGaN. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] The influence of roughness on some magnetic properties of layered structures of Fe, Co separated Cu or AuPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 1 2006I. Staniucha Abstract The system of two magnetic (M) layers divided by nonmagnetic (N) spacer is considered. Roughness in interface region is introduced employing model proposed by Bruno and Chappert. Presence of roughness leads to modification of interface exchange parameter and interface anisotropy in comparison to samples with ideal interface. The magnetisation distribution and Curie temperature has been calculated using Green function formalism for systems consisting of Fe or Co standing for M and Cu or Au standing for N, respectively. Parameters corresponding to GaAs have been taken into account to characterize the substrate. The results obtained show decreasing of Curie temperature and shift of magnetisation curve with increasing of roughness parameter. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Study of interphase in glass fiber,reinforced poly(butylene terephthalate) compositesPOLYMER COMPOSITES, Issue 1 2004A. Bergeret It is well known that application of a coupling agent to a glass fiber surface will improve fiber/matrix adhesion in composites. However, on commercial glass fibers the coupling agent forms only a small fraction of the coating, the larger part being a mixture of processing aids whose contribution to composite properties is not well defined. The interfacial region of the composite will therefore be affected by the coating composition but also by the chemical reactions involved in the vicinity of the fiber and inside the surrounding matrix. The main feature of this study consists in dividing the interface region into two separate regions: the fiber/sizing interphase and the sizing/matrix interphase. A wide range of techniques was used, including mechanical and thermomechanical tests, infrared spectroscopy, gel permeation chromatography, carboxyl end group titrations, extraction rate measurements, and viscosity analysis. Experiments were performed on poly(butylene terephthalate) composites and results indicate that the adhesion improvement is due to the presence of a short chain coupling agent and of a polyfunctional additive, which may react both with the coupling agent and the matrix. According to the nature of this additive, it may be possible to soften the interphase and then to increase the composite impact strength. [source] Electrospray ionization with ambient pressure ion mobility separation and mass analysis by orthogonal time-of-flight mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 23 2001Wes E. Steiner Rapid screening and identification of drug and other mixtures are possible using a novel ambient pressure high-resolution ion mobility (APIMS) orthogonal reflector time-of-flight mass spectrometer (TOFMS). Departing ions from the APIMS drift tube traversed a pressure interface between the APIMS and TOFMS where they were subjected to numerous gas collisions that could produce selective fragmentation. By increasing the accelerating field in the pressure interface region, the ions generated using water-cooled electrospray ionization (ESI) underwent collision-induced dissociation (CID). Mixtures of ESI ions were separated by APIMS based on their respective size-to-charge (s/z) ratios while CID and analysis of mass-to-charge (m/z) ratios occurred in the pressure interface and TOFMS. Product ions that were formed in this pressure interface region could be readily assigned to precursor ions by matching the mobility drift times. This process was demonstrated by the examination of a mixture of amphetamines and the resulting fragmentation patterns of the mobility-separated precursor ion species [M,+,H]+. Copyright © 2001 John Wiley & Sons, Ltd. [source] | ||||||||||||||||