Infrared spectroscopy is used to follow the chemical changes, as a function of temperature, after sequentially adsorbing trimethylaluminum (TMA) and methanol on hydroxylated alumina. Deuterium-labeled methanol is used to distinguish between the chemistry of methyl and methoxy species. To differentiate between methanol adsorbed on TMA-derived sites and on alumina, the adsorption of methanol is s...

OBJECTIVE To describe bauxite mining and alumina refining processes and to outline the relevant physical, chemical, biological, ergonomic, and psychosocial health risks. METHODS Review article. RESULTS The most important risks relate to noise, ergonomics, trauma, and caustic soda splashes of the skin/eyes. Other risks of note relate to fatigue, heat, and solar ultraviolet and for some opera...

Introduction Nanocrystalline gamma-phase (γ) alumina is among many polytypes of alumina that find extensive applications as a catalyst and catalytic supports. The most useful properties these aluminas provide as catalyst supports are high surface area and welldefined porosity. These properties result primarily from the nano-scale crystalline character of the alumina. The problem is that both th...

Supplier selection and evaluation is a complicated multi objective process with many uncertain factors. Sealed bid evaluation is the most common approach for supplier selection purpose in Iran. In this paper, a fuzzy expert decision support system is developed for solving the vendor selection problem with multiple objectives, in which some of the parameters are fuzzy in nature. Basic important ...

Submitted: May 19, 2013; Accepted: Jun 29, 2013; Published: Aug 07, 2013 Abstract: It is commonly recognized that knowledge is the only source of core competence in the knowledge-based companies, but productivity rate of knowledge worker is always Low. This study seeks to identify factors influence on the productivity. In addition, it presents knowledge workers clusters and measuring productivi...

A crackand pinhole-free composite membrane consisting of an a-alumina support and a modified y-alumina top layer which is thermally stable up to 1100°C was prepared by the sol-gel method. The supported thermally stable top layer was made by dipcoating the support with a boehmite sol doped with lanthanum nitrate. The temperature effects on the microstructure of the (supported and unsupported) La...

Textural evolution (porosity reduction, pore and crystallite growth) in titania-alumina composite membranes has been studied using thermal analysis, X-ray diffraction, field emission scanning electron microscopy and N, physisorption techniques. The presence of alumina in the membranes improved the thermal stability of the porous texture by retarding the anatase-to-rutile phase transformation a...

Alumina phase loaded with ammonium pyrrolidine dithiocarbamate (APDC )were synthesized based on chemical binding and physical adsorption approaches. The stability of a chemically modified APDC especially in concentrated hydrochloric acid which was then used as a recycling and pre-concentration reagent for further uses of alumina immobilized APDC phase. The application of this alumina for sorpti...

To know the electrical properties of any materials is very important for practical application of that material. In this paper I have tried to find out the proper electrical properties of Indium doped Alumina (Al2O3) for practical application of this Alumina. For this purpose all thin films are deposited on glass substrate by electron beam evaporation technique at a pressure of about 1.5 x 10-6...