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61.
The paper investigates the effect of radiation on Darcy's buoyancy induced flow of an optically dense viscous incompressible fluid along a heated inclined flat surface maintained at uniform temperature placed in a saturated porous medium with Rosseland diffusion approximation employing the implicit finite difference method together with Keller box elimination technique. Both the streamwise and normal components of the buoyancy force are retained in the momentum equations. The numerical results show that as the buoyancy parameter, ξ, increases the local Nusselt number increases. The results for the locally nonsimilar solutions are compared with the locally similar solutions for small angle of inclination and approximate similar solutions along vertical surface. The effect of the conduction-radiation parameter, R d , and the surface temperature excess ration, θ w , on the local Nusselt number, the tangential velocity distribution and the temperature distribution are also shown graphically. 相似文献
62.
63.
Free convection flow from an isothermal horizontal circular cylinder immersed in a fluid with viscosity proportional to an inverse linear function of temperature is studied. The governing boundary layer equations are transformed into a non-dimensional form and the resulting nonlinear system of partial differential equations is reduced to local non-similarity equations which are solved numerically by a very efficient implicit finite difference method together with Keller box scheme. Numerical results are presented by velocity and viscosity profiles of the fluid as well as heat transfer characteristics, namely the local heat transfer rate and the local skin-friction coefficients for a wide range of viscosity parameter (= 0.0, 0.5, 1.0, 2.0, 3.0,4.0) and the Prandtl number Pr (= 1.0, 7.0, 10.0, 15.0, 20.0, 30.0). 相似文献
64.
This paper investigates the effect of radiation on the forced and free convection flow of an optically dense viscous incompressible fluid along a heated vertical flat plate with uniform free stream and uniform surface temperature with Rosseland diffusion approximation. With appropriate transformations, the boundary layer equations governing the flow are reduced to local nonsimilarity equations valid in the forced convection regime as well as in the free convection regime. A group of transformation is, also, introduced to reduce the boundary layer equations to a set of local nonsimilarity equations valid in both the forced and free convection regimes. Solutions of the governing equations are obtained by employing the implicit finite difference methods together with Keller box scheme and are expressed in terms of local shear stress and local rate of heat transfer for a range of values of the pertinent parameters. 相似文献
65.
Manirul?IslamEmail author Dildar?Hossain Paramita?Mondal Kazi?Tuhina Anupam?Singha?Roy Sanchita?Mondal Manir?Mobarak 《Transition Metal Chemistry》2011,36(2):223-230
A thiosemicarbazone Cu(II) complex anchored to a polystyrene framework has been synthesized and characterized by analytical
and spectroscopic techniques. The complex was found to be a highly active catalyst for the oxidation of various organic substrates
including alkenes and alcohols using H2O2 as oxidant. The reaction conditions were optimized with respect to temperature, solvent, oxidant, catalyst amount, and substrate
to peroxide ratio. The heterogeneous catalyst was reused five times without significant loss of activity. A comparison between
the catalytic activities of this polymer-supported Cu(II) complex and its homogeneous analogue was carried out. 相似文献
66.
The effect of temperature on the surface phase behavior of tetradecanoyl N-ethanolamide (NHEA-14) in Langmuir monolayers at the air-water interface has been investigated by film balance and Brewster angle microscopy (BAM). It has been observed that dendritic domains are formed in the coexistence region between liquid-expanded (LE) and liquid-condensed (LC) phases at different temperatures. At 10 and 15°C, the domains are four-armed dendrites having wide arms which have a tendency to be fractal while growing in size. At 20°C, five-armed dendritic domains are formed. At a temperature higher than 20°C, the domains are mainly six-armed dendrites having very narrow and sharp arms. The formation of dendritic domains should be due to the presence of interfacial hydrogen bonding among the head groups of the amphiphile. Increased dehydration of the head groups with an increase in the temperature should be responsible for the temperature dependency of the dendritic domain shapes in the monolayers of NHEA-14. 相似文献
67.
68.
Hossain MZ Mukai K Yamashita Y Kawai H Yoshinobu J 《Chemical communications (Cambridge, England)》2011,47(37):10392-10394
The anisotropic correlation between buckled dimers on Si(100) was investigated by scanning tunneling microscopy. A bidentate ligand molecule was used to pin two neighboring dimers at 300 K. The chemically pinned dimer induces antiferromagnetic interaction along the dimer rows. Observed results agree well with Monte-Carlo simulations semi-quantitatively. 相似文献
69.
Robert C. Todd M. Mahmun Hossain Kanth V. Josyula John Kuo 《Tetrahedron letters》2007,48(13):2335-2337
Convenient methods for the preparation of BD3-THF complex were developed. Certain amines stabilize the BD3-THF for long-term storage. Regioselectivity studies were carried out with the new amine-stabilized BD3-THF with representative olefins. Hydroboration of olefins provides a convenient tool for making corresponding deuterated alcohols after oxidation. 相似文献
70.
Basudeb Basu Md.Mosharef H. BhuiyanPralay Das Ismail Hossain 《Tetrahedron letters》2003,44(50):8931-8934
An efficient and mild method for catalytic transfer hydrogenation of CC and CN double bonds with the aid of resin-supported formate (PSF) as the hydrogen donor and palladium acetate as the catalyst is reported. 相似文献