Gamma Alumina
Mostrando 1-10 de 10 artigos, teses e dissertações.
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1. Ballistic Tests of Alumina-UHMWPE Composites Submitted to Gamma Radiation
The energy absorption in ballistic tests of alumina-ultra high molecular weight polyethylene (UHMWPE) composites with 60, 80 and 90 wt% alumina submitted to gamma radiation doses of 25, 50 and 75 kGy was investigated. The ballistic tests were carried out at subsonic speed using a compressed air system. The results showed that the composite with 80% alumina i
Mat. Res.. Publicado em: 22/08/2019
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2. A Novel Synthesis Route of Mesoporous γ-Alumina from Polyoxohydroxide Aluminum
Mesoporous gamma-aluminas (γ-Al2O3) were synthesized starting from an unusual precursor of polyoxohydroxide aluminum (POHA). This precursor was obtained from aluminum oxidation in alkaline water-ethanol solvent in the presence of d-glucose that induces the formation of a gel, which leads to the POAH powder after ethanolic treatment. Precipitated POHAs were
Mat. Res.. Publicado em: 22/01/2018
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3. The Effect of Gamma-Al2O3 Support on the NO Adsorption on Pd4 Cluster
The effect of γ-Al2O3 support on the NO adsorption on Pd4 clusters was investigated by means of density functional theory (DFT) calculations. Pd4 adsorbed on γ-Al2O3 (represented by a Al14O24H6 cluster) changes its preferential geometry from tetrahedral to a distorted planar structure. The alumina support promotes a higher dispersion in the palladium catal
J. Braz. Chem. Soc.. Publicado em: 2016-11
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4. Luminescence dosimeter based on magnesium doped aluminum oxide: production and characterization. / Confecção e caracterização de dosímetro luminescente de óxido de alumínio dopado com magnésio.
The aim of the present work is to obtain and characterize luminescent dosimeters made of magnesium doped aluminium oxide, for ionizing radiation dosimetry purposes. The material is produced by Pechini Method (US Patent 3.330.697, 1967), starting from a polymer that generates powder ceramic, after firing at predetermined temperatures. Dosimetric measurements
Publicado em: 2008
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5. SÃntese e caracterizaÃÃo da alumina para dosimetria termoluminescente
Carbon-doped aluminum oxide (J-Al2O3:C) is an important material for the dosimetry of ionizing radiation using a thermoluminescent readout. This material presents a sensibility to radiation that is 50 times more sensitive than LiF:Mg,Ti. However, its fabrication usually employs crystal growing methods and high temperature laboratory infra-structure and highl
Publicado em: 2008
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6. Estudo do efeito da presença de alumina dopada com TiO2 e ZrO2 no craqueamento do óleo de soja
The catalytic cracking of triglycerides presents itself as a possible alternative to the production of biofuels with low emission of pollutants. In this work a study of the use of solids, constituted by mixed oxides of Ti, Zr and Al, as catalysts for the cracking reaction of soybean oil is presented. The study involves, after a large bibliographic review abo
Publicado em: 2006
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7. Caracterização da microestrutura de materiais porosos por microtomografia de raios x e transmissão de raios gama
This work presents the application of the X-Ray Microtomography and Gamma Ray Transmission techniques for the microstructure characterization of different kinds of materials. Total porosity, pore size distribution and the two point correlation functions were measured. The two point correlation function, which allows the reconstruction of 3D models, was carri
Publicado em: 2006
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8. Study of the Influence of additives on gamma-alpha phase transformation. / Estudo da influência de aditivos na transformação de fase gama-alfa da alumina.
O controle da temperatura de transformação de fase gama-alfa da alumina pelo uso de aditivos iônicos tem sido alvo de diversos estudos nas ultimas décadas. No entanto, os efeitos destes aditivos são usualmente explicados considerando apenas parâmetros cinéticos e de difusão e a conseqüência destas impurezas nas energias dos polimorfos e nas energia
Publicado em: 2005
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9. Structure, surface area and morphology of aluminas from thermal decomposition of Al(OH)(CH3COO)2 crystals
Crystalline aluminium hydroxiacetate was prepared by reaction between aluminium powder (ALCOA 123) and aqueous solution of acetic acid at 96ºC ±1ºC. The white powder of Al(OH)(CH3COO)2 is constituted by agglomerates of crystalline plates, having size about 10mum. The crystals were fired from 200ºC to 1550ºC, in oxidizing atmosphere and the products char
Anais da Academia Brasileira de Ciências. Publicado em: 2000-12
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10. Studies of Sulfate Utilization by Algae: 9. Fractionation of a Cell-free System from Chlorella into Two Activities Necessary for the Reduction of Adenosine 3′-Phosphate 5′-Phosphosulfate to Acid-Volatile Radioactivity 1
Further properties of the enzymatic system obtained from Chlorella pyrenoidosa (Emerson strain 3) which reduces adenosine 3′-phosphate 5′-phosphosulfate-35S to acid-volatile radioactivity, when fortified with Mg2+ and 2, 3-dimercaptopropan-1-ol as reductant, are described. Optimal concentrations of adenosine 3′-phosphate 5′-phosphosulfate-35S and Mg2