Vanadium phosphorus oxides (VPO) has been applied as a heterogeneous catalyst in gas phase oxidation reactions and its application is very limited in liquid phase. In this study a series of cobalt-doped vanadium phosphorus oxides (VPO-Co) catalysts with different loading of Co (0.01-1.0 mol ratio of Co/V) were prepared. Oxidation of benzyl alcohol was studied in the liquid phase over VPO and VP...

chitosan with excellent biodegradable and biocompatible characteristics has received attention as an oral drug delivery vehicle for controlled-release formulations. in this study an enteric-coated capsule containing theophylline-chitosan beads based on 23 factorial designs was prepared as a colon drug delivery system. the theophylline-chitosan gel beads were formulated by adding the drug-contai...

The purpose of this paper is the calculation of Unbalanced Magnetic Force (UMF) in permanent magnet brushless DC (PMBLDC) machines with diametrically asymmetric winding and investigation of UMF variations in the presence of phase advance angle. This paper presents an analytical model of UMF in surface mounted PMBLDC machines that have a fractional ratio of slot number to pole number. This model...

an account is presented on investigation of the effects of synthesis parameters, i.e., reaction sources, silica to alumina ratio, acid molar ratio and crystallization conditions on the crystallinity, morphology and particle size of sapo-34. the synthesis conditions were designed to produce small particles with narrow size range. the prepared samples were characterized by xrd and sem techniques ...

in a systematic approach, we have investigated the effect of the presence of pb and sb in the bi site in a bscco (2223 phase) superconductor. there are some contradictory reports in substitution of sb in the bi site. some researchers report an increase in the tc of these materials. so, we have made an accurate stoichiometry of these superconductors and selected extra pure starting materials wit...

the performances of two-phase polymer-liquid pebax®/polyethylene glycol (peg) and three-phase polymer-liquid-solid pebax®/peg/mwnt thin film composite membranes for co2 and ch4 permeation were studied. the effect of temperature and mwnt/pebax® ratio on single gas (co2 and ch4) permeability was investigated. the permeation of both gases was measured at different temperatures from 303 to 323 ˚k. ...

The aim of this research is to investigate different X-ray based quantitative phase analysis methods for determination of cristobalite phase content in ceramic cores. For this purpose, four popular routes including peak absolute intensity method, relative intensity ratio method, direct or calibration method and internal standard (or Alexander-Klug) method have been chosen. Some control samples ...

cobalt ferrite nano-powder have been obtained through a hydrothermal method with 2:1 molar ratio of fe:co without using any surfactant. x-ray diffraction (xrd) and scanning electron microscopy (sem) were used to consider the structural and morphological properties of cofe2o4 nano-particles. also, edax spectroscopy applied to evaluate the chemical composition. results demonstrated that 15 hr hyd...

A comprehensive study pertaining to the emulsion liquid membrane (ELM) extraction process to enrich dilute aqueous solutions of silver salt is presented. The study has highlighted the importance and influence of membrane composition for maximizing the extraction of Ag+ ions. The liquid membrane was made up of Cyanex-302 as an extractant and the industrial solvent mainly consists of p...

A Box-Behnken design with three replicates was used for preparation and evaluation of Eudragit vancomycin (VCM) nanoparticles prepared by double emulsion. The purpose of this work was to optimize VCM nanoparticles to improve the physicochemical properties. Nanoparticles were formed by using W1/O/W2 double-emulsion solvent evaporation method using Eudragit RS as a retardant material. Full factor...