A new potassium persulfate redox system has been investigated for the graft polymerization of vinyl monomers. In this study potassium persulfate system was used for initiation the polymerization. Graft polymerization of acrylonitrile (AN) onto starch (Sta) was carried out in aqueous solution using potassium persulfate (I) redox system. It was found that the percentage of grafting and rate of gr...

The kinetics and mechanisms of the substitution reactions of trans-[Co(en)2CNCl]+ with unidentate anions,  , CN¯, I¯,  , Br¯ and SCN¯ in 60% v/v DMF-H2O binary solvent at 40.0±0.2 °C were studied spectrophotometrically. An Id mechanism was assigned for the replacement of chlorine by , CN¯ and I¯, an Ia one for...

this study examines the controlled release behavior of both water-soluble (acetaminophen, caffeine, theophylline and salicylic acid) and water insoluble (indomethacin) drugs derived from caesalpinia pulcherrima seed gum isolated from caesalpinia pulcherrima kernel powder. it further investigates the effect of incorporating diluents such as microcrystalline cellulose and lactose on caffeine rele...

a theoretical study of the kinetic and mechanism of 3-aug-cope rearrangement in gas phase was performed usingdet methods at b3lyp levels of theory with 6-3114ig(d,p) bass set at 298.i5k. equilibrium moleculargeometries and harmonic vibrational frequencies of the reactant, transition state did product were calculated. then,rate constant and activation thermodynamics parameters were calculated an...

Classical xerogels are robust, inexpensive and nontoxic materials with low-ordered nanoporous structures. In water streams where the pH is higher than the Point of Zero Charge, the surface of classical xerogels such as tetraethoxy orthosilan (TEOS) xerogel is negatively charged. It was assumed that a xerogel can work as a strong adsorbent for metal ions without further modification. Therefore, ...

Background: Green tea polyphenols (GTP) are known to have several health benefits. In spite of these benefits, its application as a therapeutic agent is limited due to some of its limitations such as stability, bioavailability, and biotransformation. To overcome these limitations, liposomal nanoparticles have been used as a carrier of the GTP. <spa...

A theoretical study of the kinetic and mechanism of intramoleccha cychcation of (1)-undeca-7,8-dien-2-yne was performed using MT methods at B3LYP and B3PW91 levels of theory using 6-311g, 6-311C.6-31 IGs*, 6-31I+G, 6-31 I4-SG and 6-3114H-Gs* basis seo. Equilibrium molecular geometries andharmonic vibrational frequencies of the reaccint, transition state and product wens calculated. Theconsidere...

Objectives: This paper describes further improvement and preliminarily evaluation of a novel viscoelastic ankle-foot prosthesis prototype. The objective was to control the ankle hysteresis at slow and normal walking speeds. Methods: Inspired by the ankle biomechanics, in which the hysteresis differs based on the gait speeds, a manually damping control mechanism imbedded in the prosthesis for...

A descriptive study of isothermal kinetics of diclofenac release from chitosan-g-acrylic acid (Chit-AA) hydrogel and chitosan-g-(acrylic acid-co-[2-(acryloyloxy)ethyl]trimethylammonium chloride) (Chit-AA-AETM) hydrogel was carried out. Isothermal kinetic curves for diclofenac release from both hydrogels in distilled water at various temperatures of 20-42°C were studie...

SHAHAB is a PC- based simulator developed by Olefin Research Group (ORG), with the simultaneous simulation of the reactor, the firebox, the convection section and the transfer line exchanger in steam Cracking units. The reaction mechanism of thermal cracking of hydrocarbons is generally accepted as free-radical chain reactions. Using a rigorous kinetic model, a complete reaction network for rep...