The boundary layer equations for plane, incompressible, and steady flow are 

$$\matrix{ {u{{\partial u} \over {\partial x}} + v{{\partial u} \over {\partial y}} = - {1 \over \varrho }{{\partial p} \over {\partial x}} + v{{{\partial ^2}u} \over {\partial {y^2}}},} \cr {0 = {{\partial p} \over {\partial y}},} \cr {{{\partial u} \over {\partial x}} + {{\partial v} \over {\partial y}} = 0.} \cr }$$

Boundary Layer Theory

Organic/inorganic hybrid materials prepared by the sol–gel approach have rapidly become a fascinating new field of research in materials science. The explosion of activity in this area in the past decade has made tremendous progress in both the fundamental understanding of the sol–gel process and the development and applications of new organic/inorganic hybrid materials. Polymer-inorganic nanocomposite present an interesting approach to improve the separation properties of polymer material because they possess properties of both organic and inorganic such as good permeability, selectivity, mechanical strength, and thermal and chemical stability. Composite material derived by combining the sol–gel approach and organic polymers synthesis of hybrid material were the focus area of review It has also been demonstrated in this review that a more complete understanding of their structure–property behavior can be gained by employing many of the standard tools that are utilized for developing similar structure–property relationships of organic polymers. This review article is introductory in nature and gives introduction to composite materials/nanocomposite, their applications and the methods commonly employed for their synthesis and characterization. A brief literature survey on the polysaccharide templated and polysaccharide/protein dual templated synthesis of silica composite materials is also presented in this review article.

Sol–gel derived organic–inorganic hybrid materials: synthesis, characterizations and applications

Use of microwave irradiation in the grafting modification of the polysaccharides – A review

A mucopolysaccharide, chitosan was grafted with polyaniline through oxidative-radical copolymerization using ammonium persulfate in acidic medium. The grafting conditions were extensively studied by varying grafting parameters. All the findings have been discussed and proposed a plausible mechanism for the graft copolymerization. The representa- tive chitosan-graft-polyaniline (Ch-g-PANI) was characterized using UV-vis, FTIR, TGA, X-ray diffraction and Scanning electron microscopy taking chitosan as reference. Ch-g-PANI exhibited electrical conductivity, which increases with the extent of grafting onto chitosan backbone. Its electrical conductivity is further influenced by pH and showed pH switching electrical conduction behavior when exposed to NN3/HCl vapors. The application of conducting biomaterial such as Ch-g- PANI in the electronic devices especially for the fabrication of sensor devices would be attractive not only in terms of prod- uct cost and environmental safety but also from a materials science point of view.

/pdf/synthesis-and-characterization-of-electrical-conducting-3n2oqlo19a.pdf

Synthesis and characterization of electrical conducting chitosan-graft-polyaniline

Removal of chromium (VI) using poly(methylacrylate) functionalized guar gum.

K2S2O8/ascorbic acid initiated grafting of methylmethacrylate on to guar (Cyanaposis tetragonolobus) seed galactomannan has been studied gravimetrically at 35 ± 0.2 °C in presence of atmospheric oxygen and the conditions were optimized. Grafted guar gum was characterized using FTIR, XRD, 1H NMR and TGA analysis. Under optimal grafting conditions for the guar gum, five other wildly sourced seed galactomannans from Cassia abbreviata, Cassia javanica, Cassia reticulata, Ipomoea palmata and Ipomoea hedracea were grafted with methylmethacrylate in order to study the effect of structural diversity in the galactomannans on grafting and also for the possible commercial exploitation of these non-conventional galactomannans from Cassia and Ipomoea seeds. Results for all the galactomannans are compared and discussed.

Grafting of methylmethacrylate on to the plant seed galactomannans using potassium persulphate/ascorbic acid redox pair

This paper concerns the problem of creeping flow of an incompressible micropolar fluid past a fluid sphere with non-homogeneous boundary condition for micro rotation vector i.e. the micro rotation on the boundary of the fluid sphere is assumed to be proportional to the rotation rate of the velocity field on the boundary. The stream functions are determined by matching the solution of micropolar field equation for flow outside the fluid sphere with that of the Stokes equation for the flow inside the fluid sphere. The drag force experienced by a fluid sphere is evaluated and its variation is studied with respect to the material parameters. Some well-known results are then deduced.

/pdf/creeping-flow-of-micropolar-fluid-past-a-fluid-sphere-with-zue20oatbg.pdf

Creeping flow of Micropolar fluid past a fluid sphere with non-zero spin boundary condition

Analysis of a boundary layer flow over moving an exponentially stretching surface with variable viscosity and Prandtl number

The problem of the Stokes flow past a fluid sphere embedded in a porous medium is studied. The Brinkman equation for the flow outside the fluid sphere and the Stokes equation for inside the fluid sphere, in their stream function formulations are used. The drag force experienced by a fluid sphere embedded in a porous medium is evaluated. The dependence of the drag coefficient on permeability and viscosity ratio is presented graphically and discussed. Some previous known results are then also deduced from the present analysis.

Pankaj Shukla

Papers

Grafting of methylmethacrylate on to the plant seed galactomannans using potassium persulphate/ascorbic acid redox pair

Creeping flow of Micropolar fluid past a fluid sphere with non-zero spin boundary condition

Analysis of a boundary layer flow over moving an exponentially stretching surface with variable viscosity and Prandtl number

Drag on a fluid sphere embedded in a porous medium with solid core

MHD nanofluid flow with variable physical parameters via thermal radiation: A numerical study