Mesoporous Ni–alumina catalysts (Ni–alumina-pre and Ni–alumina-post) were synthesized by one-step sol–gel method using micelle complex comprising lauric acid and nickel ion as a template with metal source and using aluminum sec-butoxide as an aluminum source. The Ni–alumina catalysts showed relatively high surface areas (303 m/g for Ni–alumina-pre and 331 m/g for Ni–alumina-post) and narrow por...

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...

We study the effects of insulating oxides in their crystalline forms on the energy band structure of monolayer and bilayer graphene using a first principles density functional theory based electronic structure method and a local density approximation. We consider the dielectric oxides SiO(2) (α-quartz) and Al(2)O(3) (alumina or α-sapphire), each with two surface terminations. Our study suggests...

Transformation of Al(NO3)3∙9H2O (upon heating in the range of 20-1200 °C) into blends of amorphous and crystalline boehmite (210-525 °C), amorphous alumina and crystalline γ-Al2O3 (850 °C), and crystalline α-Al2O3 (1100 °C) was analyzed using X-ray diffraction (XRD), high-resolution transmission electron microscope (HRTEM), infrared (IR) spectroscopy, thermogravimetry, and low-temperature nitro...

RESUMO A casca do arroz aparece como um subproduto de grande importância para a geração energia devido ao seu elevado poder calorífico, assim as cinzas resultantes processo queima que são ricas em sílica. O objetivo principal deste trabalho foi avaliar os efeitos da incorporação cinza e alumina calcinada nas propriedades físicas térmicas cerâmicas refratárias. As matérias-primas foram caracteri...

Zirconia ultrafiltration membranes are widely developed and used for past several years. But the conventional sol-gel methods of zirconia membrane preparation involve many steps. In the present study an attempt was made to develop defect free zirconia ultrafiltration (UF) membrane in single step coating of zirconia nanopowder suspension by slip casting method over multichannel ceramic support. ...

The stability of supported metal particles is an important parameter in heterogenous catalysis. For silver catalysts on α-alumina, industrially used ethylene epoxidation, the loss surface area as result particle growth one most deactivation mechanisms. In this work, was investigated by exposing to thermal treatments. presence oxygen during heating strongly enhanced growth, and interparticle dis...

The microstructures of chemical vapor deposited coatings on four tool inserts have been comprehensively characterized using electron backscatter diffraction mapping and these data have been used as input for finite element models used to calculate the residual thermal strains in the coatings. The results indicate that the thermal strains and stored elastic energy in the α-Al2O3 layer are larger...

The present study shows that alumina nanotopography affects monocyte/macrophage behavior. Human mononuclear cells cultured on alumina membranes with pore diameters of 20 and 200 nm were evaluated in terms of cell adhesion, viability, morphology, and release of proinflammatory cytokines. After 24 hours, cell adhesion was assessed by means of light microscopy and cell viability by measuring LDH r...

The first electronic transition (Ã ← X̃) of liquid water (H2O and D2O) on an α-alumina substrate was studied using variable angle attenuated total reflection far-ultraviolet (VA-ATR-FUV) spectroscopy in the wavelength region 140-180 nm (8.86-6.89 eV). A variation in the penetration depth of the evanescent wave of a probe light (25-19 nm) directly determined individual FUV spectra associated with...