In this paper, mesoporous alumina with different pore sizes and wall crystalline structures was synthesized at calcination temperatures over 550 degrees C. The characterization of the samples calcined at 550, 800, 1100, and 1300 degrees C, respectively, was performed using TEM, XRD, FTIR, TG/DTA, and N2 adsorption/desorption techniques. The correlation between pore size and wall crystalline str...

in this research, synthesis and characterization of silver/alumina composite powders was investigated. this kind of metal/ceramic composite powders is used for fabrication of cutting tools inserts. the role of silver is toughening the final product. the powders were synthesized via co-precipitation method. the composition of the synthesized powders was ag/80% wt 〖al〗_2 o_3. silver nitrate, alum...

Attrition of six different limestones was studied during calcium looping cycles for CO2 capture in a lab-scale fluidized bed apparatus. The tests were carried out under realistic conditions representative of a process with calcination in an oxy-firing environment. The focus of the activity was to investigate the effect of the presence of SO2 both in the calcination and in the carbonation stages...

We report on the synthesis of TbMnO3 nanoparticles by chemical co-precipitation route and their structural, chemical bonding, magnetic and dielectric properties. It is shown that the interesting multiferroic properties of this system as reflected by the concurrent occurrence of magnetic and dielectric transitions are retained in the nanoparticles (size ~40 nm). However, the nanoparticle constit...

The effect of the calcination conditions on the catalytic activity for N2O decomposition of 2.5% RhOx/CeO2 catalysts has been investigated. Ramp and flash calcinations have been studied (starting calcinations at 25 or 250/350 °C, respectively) both for cerium nitrate and ceria-impregnated rhodium nitrate decomposition. The cerium nitrate calcination ramp has neither an effect on the physico-che...

Titanium dioxide (TiO(2)) nanofibers in the anatase structure were successfully prepared via electrospinning technique followed by calcination process. The morphologies, crystal structure, surface area, and the photocatalytic activity of resulting TiO(2) nanofibers were characterized by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffracti...

The influence of the reaction conditions during the transformation of hydrogen titanate nanoribbons to TiO2 nanoribbons on the phase composition, the morphology, the appearance of the nanoribbon surfaces and their optical properties was investigated. The transformations were performed (i) through a heat treatment in oxidative and reductive atmospheres in the temperature range of 400-650 °C, (ii...

Yttrium iron garnet powders have been synthesized by chemical coprecipitation using two different precursors, nitrates and chlorides, and by an oxides mixture route. It is shown that depending on the precursors and synthesis conditions used pure yttrium iron garnet powders can be obtained with a mono or multidomain magnetic behaviour. The yttrium iron garnet crystalline structure, as studied by...

Quantitative determination of Brønsted acid sites in acidic mordenite samples with varying proton concentrations has been studied using aqueous conductometric titration method. Conductometric titration of the ammonium form of mordenite with sodium hydroxide is feasible and the results indicate potential number of Brønsted acid sites. However, Brønsted acid sites concentration in acidic mordenit...