Microstructural evolution in materials during thermal processing

Copyright © 2012 Joseph K. L. Lai et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.This article has been made available through the Brunel Open Access Publishing Fund.This article is made available through the Brunel Open Access Publishing Fund

Growing importance of valvular heart disease in the elderly

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Reactive sites on the surface of polycyclic aromatic hydrocarbon clusters: A numerical study

The surface growth of soot is a key process in its mass growth, depending crucially on surface properties. In this work, we directly extract the detailed surface properties, such as surface area, number density of reactive sites on a particle and parameter α, from the microscopic configuration of polycyclic aromatic hydrocarbon (PAH) clusters. Five representative PAHs, including pyrene (C16H10), coronene (C24H12), ovalene (C32H14), hexabenzocoronene (C42H18) and circumcoronene (C54H18), are used to build the model configurations of nascent soot. We develop a numerical scheme to determine the detailed surface properties based on the approximation of solvent-excluded surface. The assumption of spherical particles is found to introduce a large uncertainty in the estimation of the surface area, and the error can be a factor of 2.5 in the worst case. The number density of atoms or sites on cluster surfaces does not depend on the chemical composition of a particle larger than 2 nm in diameter, and our study indicates that the number density of hydrogen atoms is overestimated by a factor of 3 in the literature. Finally, we propose a new equation for parameter α, which includes the effects of the size of gaseous species in surface reaction, local temperature, particle size and chemical composition

Effects of postdeposition annealing on the dielectric properties of antiferroelectric lanthanum-doped lead zirconate stannate titanate thin films derived from pulsed laser deposition

Author name used in this publication: K. H. Wong2004-2005 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Auto-ignition in turbulent combustion of hydrogen/air mixing layer at high pressure

The present work investigates the dynamic process of autoignition and extinction of flame kernels in a hydrogen/air mixing layer at a pressure of 30 atm. Direct numerical simulation (DNS) is conducted to solve the unsteady compressible flow equations coupled with reduced chemistry and detailed transport. The evolution of ignition kernels is tracked and analysed, focusing on the differences between successful and failed kernels. Parameters such as the temperature, heat release rate, scalar dissipation rate, convective and diffusive heat fluxes are calculated to provide quantitative information about ignition kernel development. The convective and diffusive heat fluxes in the successful and failed cases show marked differences. Finally, chemical explosive mode analysis (CEMA) is conducted to provide additional information

A sensitive and specific antigen detection assay for Middle East respiratory syndrome coronavirus

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Proteomic analyses reveal distinct chromatin-associated and soluble transcription factor complexes.

The current knowledge on how transcription factors (TFs), the ultimate targets and executors of cellular signalling pathways, are regulated by protein-protein interactions remains limited. Here, we performed proteomics analyses of soluble and chromatin-associated complexes of 56 TFs, including the targets of many signalling pathways involved in development and cancer, and 37 members of the Forkhead box (FOX) TF family. Using tandem affinity purification followed by mass spectrometry (TAP/MS), we performed 214 purifications and identified 2,156 high-confident protein-protein interactions. We found that most TFs form very distinct protein complexes on and off chromatin. Using this data set, we categorized the transcription-related or unrelated regulators for general or specific TFs. Our study offers a valuable resource of protein-protein interaction networks for a large number of TFs and underscores the general principle that TFs form distinct location-specific protein complexes that are associated with the different regulation and diverse functions of these TFs

Chaotic behavior in a simple DC drive

Remarkably complex behavior, namely chaotic behavior, in a simple dc chopper-fed dc motor drive system has been investigated. An iterative map that describes the nonlinear dynamics of the system operating in the continuous conduction mode is derived. It shows that different bifurcation diagrams can be obtained by varying different system parameters, and the system exhibits not only a typical period-doubling route to chaos but also the period-3 window. Analytical modeling of period-1 and hence period-p orbits as well as their stability analysis using the characteristic multipliers are presented. Thus, those stable ranges of various system parameters can be formulated, and hence the chaotic ranges can be determined. The theoretical results are verified by using both PSpice simulation and experimental measurement.published_or_final_versio