873 resultados para binary separation


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Adsorption of binary mixtures onto activated carbon Norit R1 for the system nitrogen-methane-carbon dioxide was investigated over the pressure range up to 15 MPa. A new model is proposed to describe the experimental data. It is based on the assumption that an activated carbon can be characterized by the distribution function of elements of adsorption volume (EAV) over the solid-fluid potential. This function may be evaluated from pure component isotherms using the equality of the chemical potentials in the adsorbed phase and in the bulk phase for each EAV. In the case of mixture adsorption a simple combining rule is proposed, which allows determining the adsorbed phase density and its composition in the EAV at given pressure and compositions of the bulk phase. The adsorbed concentration of each adsorbate is the integral of its density over the set of EAV. The comparison with experimental data on binary mixtures has shown that the approach works reasonably well. In the case of high-pressure binary mixture adsorption, when only total amount adsorbed was measured, the proposed model allows reliably determining partial amounts of the adsorbed components. (C) 2004 Elsevier Inc. All rights reserved.

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Quantum optics experiments on bright beams are based on the spectral analysis of field fluctuations and typically probe correlations between radio-frequency sideband modes. However, the extra degree of freedom represented by this dual-mode picture is generally ignored. We demonstrate the experimental operation of a device which can be used to separate the quantum sidebands of an optical field. We use this device to explicitly demonstrate the quantum entanglement between the sidebands of a squeezed beam.

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Marriage breakdown through separation and divorce is a pervasive feature of Australian society. But little research investigates the social factors associated with marital breakdown in Australia. This study builds on and extends Australian research by using survival analysis models to examine patterns of association among temporal, life-course, attitudinal and economic factors associated with marital breakdown. Using data from the Household Income and Labour Dynamics in Australia (HILDA) survey, we find marital breakdown in Australia is socially patterned in similar ways to other Western countries. But our findings point to several directions for future research into marriage breakdown in Australia, and we identify certain unique features of Australian marriage breakdown that warrant a more detailed investigation, such as the relationship between ethnic origin and the risk of marital breakdown.

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A dual resistance model with distribution of either barrier or pore diffusional activation energy is proposed in this work for gas transport in carbon molecular sieve (CMS) micropores. This is a novel approach in which the equilibrium is homogeneous, but the kinetics is heterogeneous. The model seems to provide a possible explanation for the concentration dependence of the thermodynamically corrected barrier and pore diffusion coefficients observed in previous studies from this laboratory on gas diffusion in CMS.(1.2) The energy distribution is assumed to follow the gamma distribution function. It is shown that the energy distribution model can fully capture the behavior described by the empirical model established in earlier studies to account for the concentration dependence of thermodynamically corrected barrier and pore diffusion coefficients. A methodology is proposed for extracting energy distribution parameters, and it is further shown that the extracted energy distribution parameters can effectively predict integral uptake and column breakthrough profiles over a wide range of operating pressures.

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The use of a fully parametric Bayesian method for analysing single patient trials based on the notion of treatment 'preference' is described. This Bayesian hierarchical modelling approach allows for full parameter uncertainty, use of prior information and the modelling of individual and patient sub-group structures. It provides updated probabilistic results for individual patients, and groups of patients with the same medical condition, as they are sequentially enrolled into individualized trials using the same medication alternatives. Two clinically interpretable criteria for determining a patient's response are detailed and illustrated using data from a previously published paper under two different prior information scenarios. Copyright (C) 2005 John Wiley & Sons, Ltd.

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Criticism of religiously motivated contributions to public policy debate is largely misconceived. It assumes that the mischief which constitutional separation of church and state is supposed to cure is a domination of the state by the church. This presents only one side of the story. Subservience by the church to the slate should also be avoided. The law of a liberal state is legitimate to the extent that it does not conflict with the basic moral values of its citizens. Therefore, an ongoing conversation about basic values is necessary. Allowing churches and individual believers the freedom to make distinctive 'religious' contributions to this conversation is consistent with the separation of church and state. It is an aspect of the liberal democratic state's obligation to listen to all perspectives on difficult moral issues. A close relationship between church and state, on the other hand, has the capacity to impede the conversation.

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A new theory of particle discharge in high tension roll (HTR) separation is presented. The discharge dynamics of an isolated charged particle resting on a conducting surface are studied first. The analysis is extended to particle discharge in a homogenous particle bed. Finally, the paper looks at the more realistic scenario of particle discharge in a non-homogenous particle bed. The consequences of the resulting theory on HTR separation are discussed. Predictions from the new theory are tested against experimental HTR separations at the pilot scale. (c) 2005 Elsevier Ltd. All rights reserved.

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Until recently the myoepithelial cell has been studied relatively little in terms of its role in breast cancer. A number of malignancies showing myoepithelial differentiation have been reported in the literature, although they are still thought to be relatively rare and only limited studies are published. As a result of recent expression profiling experiments, one type of tumor with myoepithelial features, the so-called 'basal' breast cancer, has received a renewed interest, although it has been known to pathologists for more than two decades. These tumors, which express markers of both luminal and myoepithelial cells, are now being studied using antibodies against some new molecules that have emerged from studies of sorted normal luminal and myoepithelial cells. These immunohistochemical data, combined with genomic studies, may lead to better identification and management of patients with 'basal' tumors.

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This paper investigates the relationship between mechanical properties and microstructure in high pressure die cast binary Mg-Al alloys. As-cast test bars produced using high pressure die casting have been tested in tension in order to determine the properties for castings produced using this technique. It has been shown that increasing aluminium levels results in increases in yield strength and a decrease in ductility for these alloys. Higher aluminium levels also result in a decrease in creep rate at 150 degrees C. It has also been shown that an increase in aluminium levels results in an increase in the volume fraction of eutectic Mg17Al12 in the microstructure.

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In this work, a working model is proposed of molecular sieve silica (MSS) multistage membrane systems for CO cleanup at high temperatures (up to 500 degrees C) in a simulated fuel cell fuel processing system. Gases are described as having little interactions with each other relative to the pore walls due to low isosteric heat of adsorption on silica surfaces and high temperatures. The Arrhenius function for activated transport of pure gases was used to predict mixture concentration in the permeate and retentate streams. Simulation predicted CO could be reduced to levels below the required 50 ppmv for polymer electrolyte membrane fuel cell anodes at a stage H-2/CO selectivity of higher than 40 in 4 series membrane units. Experimental validation showed predicting mixture concentrations required only pure gas permeation data. This model has significant application for setting industrial stretch targets and as a robust basis for complex membrane model configurations. (c) 2006 American Institute of Chemical Engineers.

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Dynamic binary translation is the process of translating, modifying and rewriting executable (binary) code from one machine to another at run-time. This process of low-level re-engineering consists of a reverse engineering phase followed by a forward engineering phase. UQDBT, the University of Queensland Dynamic Binary Translator, is a machine-adaptable translator. Adaptability is provided through the specification of properties of machines and their instruction sets, allowing the support of different pairs of source and target machines. Most binary translators are closely bound to a pair of machines, making analyses and code hard to reuse. Like most virtual machines, UQDBT performs generic optimizations that apply to a variety of machines. Frequently executed code is translated to native code by the use of edge weight instrumentation, which makes UQDBT converge more quickly than systems based on instruction speculation. In this paper, we describe the architecture and run-time feedback optimizations performed by the UQDBT system, and provide results obtained in the x86 and SPARC® platforms.

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We measured the effects of ethanol on glutamate receptor levels in the hippocampus of neonatal Wistar rats using a vapor chamber model. Two control groups were used; a normal suckle group and a maternal separation group. Levels of NMDA receptors were not significantly altered in ethanol-treated animals compared to the normal suckle control group, as shown by [H-3]MK-801 binding and Western blot analysis. However, MK-801 binding and NR1 subunit immunoreactivity were greatly reduced in the hippocampus of separation control animals. Neither ethanol treatment nor maternal separation altered levels of GluR1 or GluR2(4). These results have serious implications for the importance of maternal contact for normal brain development.