Synthesis and characterization of cadmium tartrate single crystals

Efforts have been successful to crystallize the electroceramic compound of cadmium tartrate through silica hydrogel. Analysis of thermograms reveals decomposition of the crystals to take place within the temperature range 65 to 442°C in air atmosphere. Some important characteristic data, i.e., valance electron plasma energy, Penn gap, Fermi energy, interionic distance, electronic polarizability have been obtained. The DC conductivity of the crystal typically lies between the conductivities of metal and insulator and we derived several pertinent parameters such as hopping energy, hopping distance, coulomb gap, etc. The micromechanical indentation of the crystal shows nonlinear variation of the impact microhardness as a function of the applied load. The estimation of fracture toughness, fragility coefficient and yield strength has too been made for the synthesized crystal. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Modelling of displacement washing of pulp fibers using orthogonal collocation on finite elements

Flow of fluid through packed bed of porous particles is modelled with the help of Peclet number (Pe) and Biot number (Bi). Packed bed is divided into three zones, flowing liquor, intrapore solute present in pores of particles and solute adsorbed on particle surface. Langmuir isotherm is used to describe the relationship between intrapore solute concentration and concentration of solute adsorbed on particle surface, whereas the bulk fluid concentration and the intrapore solute concentration are related by linear adsorption isotherm. Model predicted values are also compared with the experimental values. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Correlation between the cross-linking and degradation activation energy of cotton fabric treated with chitosan kinetic study by ‘model-free’ multiple heating rate methods

Journal of Thermal Analysis and Calorimetry - The different concentrations of chitosan were applied on cotton fabrics using glutaraldehyde as a cross-linking agent. The fabric samples were...     

OXYGEN REQUIREMENT FOR NEAR-UV MEDIATED CYTOTOXICITY OF PHENYLHEPTATRIYNE TO Escherichia coli

Abstract— Phenylheptatriyne (PHT) is a good singlet oxygen sensitizer in vitro. In vivo , its phototoxicity toward E. coli B has been proved unequivocally to depend on the presence of oxygen. The literature reports indicating that phenylheptatriyne was representative of a new class of sensitizers were probably based on experiments conducted under conditions which were not strictly anaerobic.     

Effect of donor number of solvent on the conductivity behaviour of nonaqueous proton-conducting polymer gel electrolytes

The effect of donor number of solvent on the conductivity behaviour of gel electrolytes has been studied. Liquid electrolytes were prepared by dissolving salicylic acid in solvents based on ethylene carbonate (EC), propylene carbonate (PC) and dimethylformamide (DMF) with different donor number and dielectric constant values. Three different polymers, polymethylmethacrylate (PMMA), polyacrylonitrile (PAN) and polyethylene oxide (PEO), were used as the gelling polymer. The conductivity of polymer gel electrolytes has been found to be higher than the corresponding liquid electrolytes, i.e. σ (gel)>σ (liquid). This has been explained to be due to an increase in carrier concentration by the dissociation of undissociated salicylic acid/ion aggregates present in the electrolytes with the addition of polymer. However, the relative increase in conductivity observed with the addition of different gelling polymers has been found to depend upon the donor number of the solvent used.     

A Trust Region SQP Algorithm for Equality Constrained Parameter Estimation with Simple Parameter Bounds

We describe a new algorithm for a class of parameter estimation problems, which are either unconstrained or have only equality constraints and bounds on parameters. Due to the presence of unobservable variables, parameter estimation problems may have non-unique solutions for these variables. These can also lead to singular or ill-conditioned Hessians and this may be responsible for slow or non-convergence of nonlinear programming (NLP) algorithms used to solve these problems. For this reason, we need an algorithm that leads to strong descent and converges to a stationary point. Our algorithm is based on Successive Quadratic Programming (SQP) and constrains the SQP steps in a trust region for global convergence. We consider the second-order information in three ways: quasi-Newton updates, Gauss-Newton approximation, and exact second derivatives, and we compare their performance. Finally, we provide results of tests of our algorithm on various problems from the CUTE and COPS sets.     

Influence of magnetic field on the photorefractive effect in LiNbO3 crystals

The photorefractive effect has been studied experimentally in single crystals of Fe and Mn-doped lithium niobate as a function of external static magnetic field. A strong dependence of changes in birefringence is observed on the magnitude and direction of the external field.