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1.
A closed-form expression is presented to find the location of solid-liquid interface motion in convection-dominated solidification and melting problems. In this regard, the solutions are expressed in terms of the generalized representations of error functions,E (u, v) andF (u, v), which are useful to heat-conduction problems with convective-type boundary conditions. It is demonstrated that for constant surface temperature, the interface solution reduces to the classical Neumann solution. 相似文献
2.
The solubility and diffusion coefficient of carbon dioxide in intermediate‐moisture starch–water mixtures were determined both experimentally and theoretically at elevated pressures up to 16 MPa at 50 °C. A high‐pressure decay sorption system was assembled to measure the equilibrium CO2 mass uptake by the starch–water system. The experimentally measured solubilities accounted for the estimated swollen volume by Sanchez–Lacombe equation of state (S‐L EOS) were found to increase almost linearly with pressure, yielding 4.0 g CO2/g starch–water system at 16 MPa. Moreover, CO2 solubilities above 5 MPa displayed a solubility increase, which was not contributed by the water fraction in the starch–water mixture. The solubilities, however, showed no dependence on the degree of gelatinization (DG) of starch. The diffusion coefficient of CO2 was found to increase with concentration of dissolved CO2, which is pressure‐dependent, and decrease with increasing DG in the range of 50–100%. A free‐volume‐based diffusion model proposed by Areerat was employed to predict the CO2 diffusivity in terms of pressure, temperature, and the concentration of dissolved CO2. S‐L EOS was once more used to determine the specific free volume of the mixture system. The predicted diffusion coefficients showed to correlate well with the measured values for all starch–water mixtures. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 607–621, 2006 相似文献
3.
An electrolytic device for decomposition of water has been developed which readily gives hydrogen and oxygen for isotopic measurement with a mass spectrometer. A 20-mul sample can be decomposed quantitatively in 10 min with good reproducibility. The results produced are comparable with those obtained by reduction with uranium. 相似文献
4.
Rashid A. Zeineh George Kyriakidis A. Rashid Bhatti 《Applied biochemistry and biotechnology》1986,13(2):111-117
Virion polypeptides (35 S), methionine-labeled and purified by CsCl gradient centrifugation, were separated by SDS-gel electrophoresis. Analysis of their band pattern was performed by scanning the images of the SDS-gels shown on a 35-mm slide. The densitometric tracings revealed the presence of 17 protein bands, although only 15 of them were visible to the naked eye. The high sensitivity and resolving capacities of the soft-laser scanning densitometer enabled us to detect trace amounts of protein bands separated in SDS-gels and to obtain a resolution compatible to that of electrophoresis. Fourfold electronic amplification of the densitometric tracings, produced by a computer, generated new information regarding the pattern of the electrophoregram. The facility to amplify peaks of importance is particularly advantageous when faint or overlapping protein bands revealed on a gel are assessed. 相似文献
5.
T. Jabbar M. S. Subhani K. Khan A. Rashid S. D. Orfi A. Y. Khan 《Journal of Radioanalytical and Nuclear Chemistry》2003,258(1):143-149
A study on the concentration of natural and fallout radionuclides in environmental samples collected from different localities of Islamabad was performed. For the determination of gamma-emitters such as 238U, 232Th, 40K and 137Cs high purity germanium (HPGe) detector was used while for the analysis of 90Sr, a beta-emitter, liquid scintillation counting system was used. The indoor absorbed dose rate was measured by a CaF2 : Dy thermoluminescence detector. Other radiation parameters were also determined to evaluate the radiation hazard. All the results were well within the permissible limits showing that there is no radiation hazard in the environment of Islamabad. 相似文献
6.
7.
In view of the attributed medicinal properties of beta-carboline alkaloids, some new O-acyl derivatives of beta-carboline alkaloid--harmol, were prepared and tested for possible antimycobacterial activity against Mycobacterium tuberculosis H37Rv. 相似文献
8.
Syed A. Ali Mohammed A. Siddiqui and Mohammed A. Ali 《Reaction Kinetics and Catalysis Letters》2005,87(1):199-206
Summary A parametric study of catalytic reforming process in a pilot plant was carried out by varying the pressure, H2/HC ratio, and space velocity. The results show that lower aromatics and higher hydrogen yields can be accomplished by increasing
the space velocity in existing reformers, which will also result in better C5+yield. 相似文献
9.
Ahmad VU Zubair M Athar Abbasi M Abid Rashid M Rasool N Nahar Khan S Iqbal Choudhary M Kousar F 《Magnetic resonance in chemistry : MRC》2005,43(6):486-488
The investigation of the chemical constituents of Symplocos racemosa Roxb led to the isolation of two new glycosides, symcomoside A (1) and symcomoside B (2), together with one known glycoside, tortoside C (3), which is reported for the first time from this plant. The structures of the new compounds were determined by 1D and 2D homonuclear and heteronuclear NMR spectroscopy, from chemical evidence and by comparison with published data for closely related compounds. Symcomoside B (2) showed potent inhibitory activity against alpha-glucosidase in a concentration-dependent fashion with an IC50 value of 0.733 +/- 0.033 mM whereas symcomoside A (1) showed very weak inhibitory activity against alpha-glucosidase (9.90% in 0.70 mM). 相似文献
10.
Abdou O. Abdelhamid Cyril Prknyi S. M. Khaledur Rashid Winston D. Lloyd 《Journal of heterocyclic chemistry》1988,25(2):403-405
Substituted 2-arylbenzimidazoles, 2-arylbenzoxazoles and 2-arylbenzothiazoles were obtained in good yield by the reaction of hydroximoyl chlorides with ortho-substituted aromatic amines. The benzo moiety of the benzimidazoles was shown by nmr to be symmetrical, indicating that the N-H group proton of the imidazole ring is exchanging with the water protons in the DMSO-d6 solvent. 相似文献