999 resultados para Preparação da amostra


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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The waste, exaggerated and incorrect disposal of biomass are common practices in modern times where everything is disposable. However the growing concern with the nature and the environment compel man to give nobler destinations for these products through sustainability and recycling of waste. Banana peel is a residual biomass, which is not consumed. It generates tons of waste per week in São Paulo city. This trash is disposed in dumps and landfills, which could be reduced by using it as reinforcement in natural composites. The high density polyethylene (HDPE) is a polymer derived from the ethylene polymerization and is easily recycled. Which makes it a sustainable material. In the present work characteristics of the natural composite composed with banana peel and high-density polyethylene were studied. It was noted that removing the lignin present in the banana peel, the fiber introduces a significant improvement in thermal resistance. The preparation of composite was made with a ratio of 5% and 10% of reinforcement in comparison with polymeric matrix mass. Composites were thermally, mechanically and microscopically characterized. The addition of fiber in the polymer increased the mechanical strength of the composite. The fiber surface treatment with distilled water removed the amorphous material present in the fibers, improving significantly thermal stability and increasing crystallinity of the celullose. The addition of 5% fiber in mass to the polymer increased significantly the tensile strength and elasticity modulus for the composite. With 10% of fiber addiction there were also an improvement when compared with pure HDPE, but when compared with 5% composite the mechanical properties are slightly lower. This may be due to the fiber particle size, which are small and eventually become a hub of tension ... (Complete abstract click electronic access below)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Cu(II), Cd(II), Mn(II) AND Ni(II). Cellulose acetate polymeric membranes had been prepared by a procedure of two steps, combining the method of phase inversion and the technique of hydrolysis-deposition. The first step was the preparation of the membrane, and together was organomodified with tetraethylortosilicate and 3-aminopropyltrietoxysilane. Parameters that exert influence in the complexation of the metallic ion, as pH, time of complexation, metal concentration, had been studied in laboratory using tests of metal removal. The membranes had presented resistance mechanics and reactivity to cations, being able to be an alternative for the removal, daily pay-concentration or in the study of the lability of metals complexed.

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Pós-graduação em Bases Gerais da Cirurgia - FMB

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From the last decade of the twentieth century, the rapid growth of nanotechnology has resulted in the discovery of a number of forms of nanoparticles and nanoclusters. We can cite as an example: nanotubes, nanowires, nanobelts, and nanoconesnanoclusters which have a wide range of applications, particularly as catalysts magnetic material nanodevices, chemical sensors, degradation of toxic chemicals, or even as possible carriers for the isotope medical applications.. The first step is the production and characterization of nanowires multithreaded using different types of metals (nickel, silver, gold) and polymers (pyrrole), which are prepared by electrochemical deposition process. Will be held by the characterization of the same images of scanning electron microscopy (SEM) and transmission electron microscopy (TEM)

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This study aims to verify the reduction phenomenon and/or disappearance of vowels, especially unstressed vowels in PE compared to the PB, obtained by analysis of the recording of an oral reading sample of the Mar Português poem, by Fernando Pessoa, made by informants of the two variants. The noticeable difference in pronunciation of the informants, with any possibility of reaching up to no understanding of European pronunciation by Brazilian speakers motivated the development of an experiment that allowed us to compare the duration of vowels produced in the two variants. By isolating and measuring the vowels at Praat audio analysis program, this study was to confirm the reduction and, in extreme cases, the disappearance of unstressed vowels in PE, a phenomenon described in Mateus and D'Andrade (2000)

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Pós-graduação em Química - IQ

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Within a broader study of the apparatus governing the establishment of word classes in grammatical tradition, this study is centered on examining the treatment of the (sub)class of pronouns in two grammar guide groups from different periods. The collation was especially oriented by the existing general notion of a very strong link of the first grammarians with logic and, as a counterpart, of an insertion of the most recent works in the universe of a linguistic science and, at the same time, in the universe of a parameterization limiting actions and decisions.

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Pós-graduação em Ciência dos Materiais - FEIS