Comparison between homotopy analysis method and optimal homotopy asymptotic method for nth‐order integro‐differential equation

This paper presents general framework for solving the nth‐order integro‐differential equation using homotopy analysis method (HAM) and optimal homotopy asymptotic method (OHAM). OHAM is parameter free and can provide better accuracy over the HAM at the same order of approximation. Furthermore, in OHAM the convergence region can be easily adjusted and controlled. Comparison, via two examples, between our solution using HAM and OHAM and the exact solution shows that the HAM and the OHAM are effective and accurate in solving the nth‐order integro‐differential equation. Copyright © 2011 John Wiley & Sons, Ltd.     

Micellar properties of a phenothiazine drug in presence of additives

In this study micellar properties of a phenothiazine drug, promazine hydrochloride, at different concentrations of NaCl and cationic surfactants (conventional as well as gemini surfactants) are presented. The parameters studied are cmc (critical micelle concentration), X ₁ (mole fraction of surfactant in micelles), f ₁, f ₂ (activity coefficients) and ΔG _ex (excess free energy). Cl⁻ ions (from NaCl) get adsorbed on the micellar head groups and, by decreasing the repulsion among them, lower the cmc. Surfactants form mixed micelles with the drug and the values of X ₁, X ₁^id (mole fraction of the surfactant in micelles in ideal state), interaction parameter β, f ₁ and f ₂ all suggest non-ideal but synergistic nature. The ΔG _ex values are negative indicating that the mixed state is more stable than the pure micelle state. The article is published in the original.     

APPLICATION OF SHELLAC IN POLYMERS

Abstract

Lac is the only known natural resin of animal origin. It is the secretion of a tiny insect known as Kerriar lacca (formally called Laceifer lacca). The lac-forming tiny insect grows on some types of trees, mostly abundant in tropical countries, including India. The secretion of the lac insect hardens in air and forms a covering on the body of the insect. This covering or the nest forms a continuous incrustation on the branches of the host trees. Lac is collected by scraping the incrustation from the branches of the trees.