Analysis of slip flow heat transfer between two unsymmetrically heated parallel plates with viscous dissipation

This paper presents an analytical investigation to study the heat transfer and fluid flow characteristics in the slip flow region for hydrodynamically and thermally fully developed flow between parallel plates. Both upper and lower plates are subjected to asymmetric heat flux boundary conditions. The effect of first order velocity slip, temperature jump, asymmetric heat flux ratio and viscous dissipation on the heat transfer performance is analyzed. Closed form expressions are obtained for the temperature distribution and Nusselt number. Present predictions are verified for the cases that neglect the viscous heating and microscale effects. The effect of asymmetric heat flux ratio with and without viscous dissipation on Nusselt number for both macroscale and microscale is highlighted. The heat transfer characteristics are found to depend on various modeling parameters, namely, modified Brinkman number, Knudsen number and heat flux ratio.     

The Kinetics of the transesterification of Simarouba glauca oil for the production of biofuel using zirconia-based catalysts

This study reveals the synthesis of biofuel (BF) from Simarouba glauca (SG) oil through the process of transesterification using honeycomb (HC) coated with modified forms of zirconia as basic catalysts. Zirconia and its modified forms such as zirconia-calcia and zirconia-magnesia were coated on monoliths by the dip-dry method and were characterized for their surface basicity, powder X-ray diffraction, infrared, and scanning electron microscopy (SEM) techniques. The effect of incorporation of calcium/magnesium ions on the basicity, crystallinity, and catalytic activity of zirconia is discussed. Kinetic study reveals that zirconia-calcia coated on the HC exhibits the lowest energy of activation (Ea) in transesterification and hence is an efficient catalyst for BF synthesis.     

Dimensional Chains Involving Rectangular and Normal Error-Distributions

The marginal distribution of a normally distributed variable whose mean is rectangularly distributed is derived and the formula for the cumulative probability function of the sum of two such variables is also given. The results may be helpful in setting exact tolerances for mating parts and their assemblies.     

Development of formaldehyde-free leathers in the perspective of retanning: part II. Combination of formaldehyde-free retanning syntans

There is a growing demand for the formaldehyde-free leathers in global leather market due to increasing awareness towards eco-labelling. The first part of this work described the optimisation of formaldehyde-free syntans in their applications as single syntans in making leathers with desired properties. In this work the use of formaldehyde-free syntans in combination to produce leathers with desired properties has been attempted. Three combination-retanning systems have been chosen using formaldehyde-free resin, acrylic and protein syntans. The performance of leathers in terms of bulk and strength properties is shown to be comparable or even better for all the combination-retanning systems chosen compared to the control system. In particular, Experiment “C” (resin syntan 3%, acrylic syntan 4% and protein syntan 2%) provides leathers with improved bulk, strength and colour properties as well as reduced COD and TS loads, besides not having free formaldehyde. Scanning electron microscopic study reveals that the extent of filling in all the three combination-retanning systems is similar.     

Direct Writing of Polycaprolactone Polymer for Potential Biomedical Engineering Applications

Topography, which in this paper includes the surface features and the features themselves, is a crucial physical cue for cells, influencing cell adhesion, proliferation and differentiation and should be considered when designing biomedical architectures. A new technique using electrohydrodynamic (EH) print‐patterning is described that generates ordered topographies using proven biomaterials and composites. Coupling this method with solvent evaporation techniques, desirable scaffold properties can be achieved. To demonstrate this, various solutions of polycaprolactone (PCL) and its composites (using nano‐hydroxyapatite (nHA)) have been selected to generate topographic and 3D structures. Electrically driven patterning of the polymer is achievable and can be used to deposit fine (<5 µm) ordered structures, according to a predetermined architecture via a computer with control on porosity and bioactivity. The results from this study indicate that this method to deposit bioactive structures with morphology control will offer great potential in biomedical engineering.     

Phonon Frequency Spectrum HTSC YbBa2Cu3O7

Since the discovery of the high T _c superconductivity by Bednorz and Muller, several workers around the world have studied several systems to reach a really high T _c superconductor. As the strong electron-phonon coupling may be one of the possible origins of the high T _c , a knowledge about the phonon in these materials is essential. In order to investigate phonon spectra, one has to study Raman and infrared spectra of these systems. But there is a little information about the Raman spectra and infrared absorption spectra are available in the literature. Hence, a theoretical evaluation of phonon frequencies of high temperature superconductors assume importance. Due to strong covalent bonding nature in high temperature superconductors, a normal coordinate analysis using Wilson??s FG matrix is applied to evaluate Phonon frequencies. The normal coordinate analysis of optically active lattice vibrations will be useful for the theoretical interpretation of vibrational spectrum at the center of Brillouin zone in high T _c superconductors. Hence, an attempt is made to evaluate all the phonon frequencies of HTSC YbBa₂Cu₃O₇ through normal coordinate analysis. Calculations of lattice dynamics is also performed by use of the modified three body force shell model. The present approach leads to a better understanding of phonon frequency of high T _c superconductor YbBa₂Cu₃O₇ under investigations in the present work. This calculations yield not only the zone center phonon modes but also the stable dispersion curves through out the Brillouin zone. It also supports strong electron-phonon interactions in high T _c superconductors.     

Oblique observation speckle shear interferometers for slope change contouring

Abstract

Two new simple speckle shear interferometry configurations for slope change contouring of three-dimensional curved objects are presented in this paper. Analysis has shown that the first configuration is sensitive only for slope change variations of the object and is insensitive to all other deformations while the second configuration yields fringes corresponding to slope change and contouring and is free from shadowing. Detailed theory and experimental results on a domestic light bulb are presented. These configurations provide controllable sensitivity and can easily be adopted in television shearography.