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S.K. Mahapatra B.K. Dandapat 《Journal of Quantitative Spectroscopy & Radiative Transfer》2006,102(2):277-292
The current study addresses the mathematical modeling aspects of coupled conductive and radiative heat transfer in the presence of absorbing, emitting and isotropic scattering gray medium within two-dimensional square enclosure. A blended method where the concepts of modified differential approximation employed by combining discrete ordinate method and spherical harmonics method, has been developed for modeling the radiative transport equation. The gray participating medium is bounded by isothermal walls of two-dimensional enclosure which are considered to be opaque, diffuse and gray. The effect of various influencing parameters i.e., radiation-conduction parameter, surface emissivity, single scattering albedo and optical thickness has been illustrated. The adaptability of the present method has also been addressed. 相似文献
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Amit S. Nagare Arpan Manna Pramod D. Sonawane Anil Kumar 《Journal of Physical Organic Chemistry》2015,28(11):665-673
Prevailing classification of salts based on their effect in solubility and stability of proteins in aqueous solution predicts that tetraalkylammonium salts, guanidinium chloride (GnCl), LiClO4 act as salting‐in (S/I) and LiCl, NaCl act as salting‐out (S/O) in aqueous conditions. In the same context the behaviour of GnCl, LiClO4 and LiCl are contradictory in polar solvents like ethylene glycol and formamide. In these solvents, expected salt effect shows just opposite nature from their usual expectation. However, in the aqueous solution salts like tetraalkylammonium halide (R4NX, R = alkyl group, X = Br group) behave like salting‐in salts. The physicochemical origin of the salting in effect of R4NX type of salts has been discussed elaborately in the present work. The role of cations in terms of substitution of various alkyl groups on R4NX has been systematically presented here on the basis of experimental kinetic and thermodynamic studies. The abnormal behaviour of R4NX salts in aqueous solution has also been explained by the Setschenov equation (ks) and Δμsolvation values, which highlights their individual nature out of common properties of R4NX. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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Invoking Pairwise Interactions in Water‐Promoted Diels–Alder Reactions by using Ionic Liquids as Cosolvents 下载免费PDF全文
Rate constants and derived activation parameters of organic reactions in aqueous media, in particular Diels–Alder reactions, are sensitive to the presence of cosolvents in water. To enhance the solubility window of water, we introduced ionic liquids as cosolvents in the aqueous Diels–Alder reaction between anthracene‐9‐carbinol and N‐ethylmaleimide. The reactive potentials of the organic compounds are parameterized by using semi‐empirical quantum chemical methods. The principle of Savage–Wood additivity of group interactions is used to quantify the pairwise group interactions among chemically inert ionic liquids and organic reactants, both at initial and transition states of the reaction. The present approach shows promise, as the use of simple calculations from easily available kinetic data can help researchers to understand the versatility of green ionic‐liquid alternatives to volatile organic solvents. 相似文献
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A mathematical model for the flow and heat transfer in a gravity-driven liquid film is presented, in which the strict Boussinesq approximation is adopted to account for buoyancy. A similarity transformation reduces the governing equations to a coupled set of ordinary differential equations. The resulting two-parameter problem is solved numerically for Prandtl numbers ranging from 1 to 1000. Favourable buoyancy arises when the temperatureT w of the isothermal surface is lower than the temperatureT 0 of the incoming fluid, and the principal effects of the aiding buoyancy are to increase the wall shear and heat transfer rate. For unfavourable buoyancy (T w>T 0), the buoyancy force and gravity act in opposite directions and the flow in the film boundary layer decelerates, whereas the friction and heat transfer are reduced. The observed effects of buoyancy diminish appreciably for higher Prandtl numbers. 相似文献
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Parmar A Singh K Bahadur A Marangoni G Bahadur P 《Colloids and surfaces. B, Biointerfaces》2011,86(2):319-326
The solubilization of four phenolic antioxidants, namely p-hydroxybenzoic acid (PHBAA), syringic acid, sinapic acid, and quercetin in micelles of an ethylene oxide (EO)–propylene oxide (PO) triblock copolymer Pluronic® P104 (EO27–PO61–EO27, PPO mol wt = 3540, % PEO = 40) was examined at different temperatures, pHs, and in the presence of sodium chloride. The nano-size core–shell micelles of P104 characterized by dynamic light scattering had hydrodynamic diameter of about 18–20 nm with low polydispersity. Antioxidants induced micellization and micellar growth were observed. The critical micellar concentration (CMC), critical micellar temperature (CMT), cloud point (CP) of P104 decreased due to solubilization and interactions of antioxidants. The solubilization was favored at higher temperature, pH and in the presence of salt and follows the order PHBA > syringic acid > sinapic acid > quercetin which corresponds to the trend in their aqueous solubility. The location of antioxidant in micelles observed from NOESY spectra. Structure and hydrophobicity of antioxidants were found to be governing factors for their interaction and location in the micelles. 相似文献
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A bimetallic pillared-layer coordination framework {[Mn(3)(bipy)(3)(H(2)O)(4)][Cr(CN)(6)](2)·2(bipy)·4(H(2)O)}(n) has been constructed using a cyanometallate anion ([Cr(CN)(6)](3-)) and an organic linker (4,4'-bipyridyl) that provides high heat of hydrogen adsorption (~11.5 kJ mol(-1)) and shows guest dependent magnetic modulation. 相似文献
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B. S. Dandapat A. Kitamura B. Santra 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2006,57(4):623-635
In this paper we have studied a non-planar thin liquid film flow on a planar stretching surface. The stretching surface is
assumed to stretch impulsively from rest and the effect of inertia of the liquid is considered. Equations describing the laminar
flow on the stretching surface are solved analytically. It is observed that faster stretching causes quicker thinning of the
film on the stretching surface. Velocity distribution in the liquid film and the transient film profile as functions of time
are obtained.
(Received: May 4, 2004; revised: February 2/August 24, 2005) 相似文献
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An optically reversible switching membrane surface 总被引:1,自引:0,他引:1