449 resultados para Concentrado
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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The need for development of new materials is a natural process in the companies’ technological point of view, seeking improvements in materials and processes. Specifically, among the materials, ceramic exhibit valuable properties, especially the covalent ceramics which have excellent properties for applications which requires the abrasion resistance, hardness, high temperatures, resistence, etc. being a material that has applications in several areas. Most studies are related to improvement of properties, specially fracture toughness that allows the expansion of its application. Among the most promising ceramic materials are silicon nitride (Si3N4) which has excellent properties. The goal of this work was the development and caracterization of Si3N4-based ceramics, doped with yttrium oxide (Y2O3), rar earth concentrate (CTR2O3) and cerium oxide (CeO2) in the same proportion for the evaluation of properties. The powders' mixtures were homogenized, dried and compressed under pressure uniaxial and isostatic. Sintering was carried out in 1850 ⁰C under pressure of 0,1MPa N2 for 1 h with a heating rate of 25 ⁰C / min and cooling in the furnace inertia. The characterizations were performed using Archimedes principle to relative density, weight loss by measuring before and after sintering, phase analysis by X-ray diffraction, microstructure by scanning electron microscope (SEM), hardness and fracture toughness by the method Vickers indentation. The results obtained showed relative density of 97-98%, Vickers hardness 17 to 19 GPa, fracture toughness 5.6 to 6.8 MPa.m1/2, with phases varying from α-SiAlON and β-Si3N4 depending the types of additives used. The results are promising for tribological applications and can be defined according to the types of additives to be used
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Pós-graduação em Ciência e Tecnologia Animal - FEIS
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Pós-graduação em Ciência e Tecnologia Animal - FEIS
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Pós-graduação em Zootecnia - FCAV
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Pós-graduação em Engenharia Mecânica - FEB
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Pós-graduação em Zootecnia - FCAV
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Pós-graduação em Zootecnia - FCAV
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Pós-graduação em Zootecnia - FCAV
Características da carne de cordeiros alimentados com glicerina proveniente da produção de biodiesel
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Pós-graduação em Zootecnia - FCAV
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The present monograph studies the speech of the people from Ibiraci, MG. It is a phonetic study which collects speech data by recordings. It has been recorded the speech of eight informants with the age between 20 and 85 years old. The phonetic objective is to transcribe the recordings for acoustic analysis with Praat program, considering aspects such as duration and intonation. The present monograph represents a contribution for the linguistic phonetic description of a Brazilian Portuguese variety. In Brazil, linguistic studies have always been considered the speech of people from big and capital cities. There are a great deal of data related to those cities, but only a few data collection for the other cities and communities
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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The paper analyses the concentration degree in the global steel industry in the 1990-2010 period. Using the Herfindahl-Hirschman (HHI) index, the paper has concluded that concentration in the world steel industry increased, mainly because the increase of acquisitions and fusions among firms.