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Resulting Solution (resulting + solution)

Distribution by Scientific Domains
Engineering40%

Selected Abstracts

Approximation to the interface velocity in phase change front tracking

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 2 2002
P. H. Zhao
Abstract Numerical models for front tracking in the sharp interface limit must calculate the interface velocity by means of a differentiation of the temperature field on both sides of the interface, the resulting velocity shows an oscillatory error that introduces noise in the solution. In unstable solidification problems, the noise can actually change the resulting solution. In this work, we look at the effect of the noise in the solution of dendritic solidification in an undercooled melt and analyse ways to control it. We conclude that at this point, we cannot suppress the noise and that methods to reduce it can actually lead to different solutions to the same problem. Copyright © 2001 John Wiley & Sons, Ltd. [source]

Structure and Properties of CdS/Regenerated Cellulose Nanocomposites

MACROMOLECULAR MATERIALS & ENGINEERING, Issue 10 2005
Dong Ruan
Abstract Summary: Novel inorganic-organic hybrid materials composed of cadmium sulfide (CdS) semiconducting nanocrystals and regenerated cellulose (RC) were prepared by using in situ synthesizing method. Cellulose was dissolved in a 6 wt.-% NaOH/4 wt.-% urea/thiourea aqueous solution at low temperature followed by addition of cadmium chloride (CdCl2), resulting that the CdS nanocrystals were successfully grown in situ in the cellulose solution. Nanocomposite films containing homogeneous CdS nanoparticles were obtained by casting the resulting solution. Their structure and optical properties were characterized by X-ray photoelectron spectroscopy, wide-angle X-ray diffraction, thermogravimetry analysis, dynamic mechanical analysis, atomic force microscopy, transmittance electronic microscope, UV-vis spectroscopy, and photoluminescence spectroscopy. The experimental results confirmed that the CdS nanocrystalline existed in the composite films, and cellulose matrix provided a confined medium for CdS particle growth in uniform size. The CdS/RC composites showed narrow emission in photoluminescence spectra, and their optical absorbance in the UV range was higher than that of the cellulose film without CdS. This work provided a simple method to prepare cellulose functional materials in NaOH/urea aqueous solution. Photoluminescence of CdS/RC nanocomposites and TEM image of CdS nanocrystals dispersed in RC matrix. [source]

The design of an on-line semi-preparative LC,SPE,NMR system for trace analysis,

MAGNETIC RESONANCE IN CHEMISTRY, Issue 9 2005
Feng Xu
Abstract This paper reports the design of an on-line semi-preparative LC,SPE,NMR system and its use in the structural analysis of mixture components at the 0.02,1% level. The combination provides at least a five fold mass sensitivity increase over that obtained from typical analytical LC,SPE systems and a >30-fold total NMR sensitivity enhancement over analysis by LC,NMR. This is accomplished by using a novel on-line device to store, dilute (1,100-fold) and deliver (at an optimized flow-rate) the isolated component of interest to an SPE trap unit. The SPE unit consists of two cartridges connected in parallel to increase the overall SPE capacity and also to decrease the flow-rate through each trap for enhanced trapping efficiency. As the coupling of semi-preparative LC with NMR (through SPE) is well matched in terms of optimal mass loading for both techniques, only one LC,SPE cycle is required to enrich a 50 µg ml,1 component (1% in a 5 mg ml,1 mixture) for the acquisition of heteronuclear 1H,13C NMR data using a conventional NMR flow probe. Furthermore, analytes at the 0.02% level (,1 µg ml,1) can be studied using 2D 1H NMR techniques if peak cuts from replicate sample injections (,3) are accumulated into the storage/dilution unit and the resulting solution processed by just one SPE trap and elute cycle. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Elucidation of the mechanism and end products of glutaraldehyde crosslinking reaction by X-ray structure analysis

BIOTECHNOLOGY & BIOENGINEERING, Issue 3 2007
Yariv Wine
Abstract Glutaraldehyde has been used for several decades as an effective crosslinking agent for many applications including sample fixation for microscopy, enzyme and cell immobilization, and stabilization of protein crystals. Despite of its common use as a crosslinking agent, the mechanism and chemistry involved in glutaraldehyde crosslinking reaction is not yet fully understood. Here we describe feasibility study and results obtained from a new approach to investigate the process of protein crystals stabilization by glutaraldehyde crosslinking. It involves exposure of a model protein crystal (Lysozyme) to glutaraldehyde in alkaline or acidic pH for different incubation periods and reaction arrest by medium exchange with crystallization medium to remove unbound glutaraldehyde. The crystals were subsequently incubated in diluted buffer affecting dissolution of un-crosslinked crystals. Samples from the resulting solution were subjected to protein composition analysis by gel electrophoresis and mass spectroscopy while crosslinked, dissolution resistant crystals were subjected to high resolution X-ray structural analysis. Data from gel electrophoresis indicated that the crosslinking process starts at specific preferable crosslinking site by lysozyme dimer formation, for both acidic and alkaline pH values. These dimer formations were followed by trimer and tetramer formations leading eventually to dissolution resistant crystals. The crosslinking initiation site and the end products obtained from glutaraldehyde crosslinking in both pH ranges resulted from reactions between lysine residues of neighboring protein molecules and the polymeric form of glutaraldehyde. Reaction rate was much faster at alkaline pH. Different reaction end products, indicating different reaction mechanisms, were identified for crosslinking taking place under alkaline or acidic conditions. Biotechnol. Bioeng. 2007;98:711,718. © 2007 Wiley Periodicals, Inc. [source]

Coupling BEM/TBEM and MFS for the simulation of transient conduction heat transfer

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 2 2010
António Tadeu
Abstract The coupling between the boundary element method (BEM)/the traction boundary element method (TBEM) and the method of fundamental solutions (MFS) is proposed for the transient analysis of conduction heat transfer in the presence of inclusions, thereby overcoming the limitations posed by each method. The full domain is divided into sub-domains, which are modeled using the BEM/TBEM and the MFS, and the coupling of the sub-domains is achieved by imposing the required boundary conditions. The accuracy of the proposed algorithms, using different combinations of BEM/TBEM and MFS formulations, is checked by comparing the resulting solutions against referenced solutions. The applicability of the proposed methodology is shown by simulating the thermal behavior of a solid ring incorporating a crack or a thin inclusion in its wall. The crack is assumed to have null thickness and does not allow diffusion of energy; hence, the heat fluxes are null along its boundary. The thin inclusion is modeled as filled with thermal insulating material. Copyright © 2010 John Wiley & Sons, Ltd. [source]