58 resultados para Alteração mineralógica


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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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As argilas vermelhas, utilizadas para cerâmica estrutural e de revestimentos, apresentam variações significativas que se refletem no comportamento apresentado durante o uso, para obtenção de determinado produto. Dentro de cada segmento industrial há requisitos básicos para que uma determinada argila ou mistura tenha capacidade de dar produtos que se encaixem dentro das respectivas Normas. Um dos parâmetros básicos para sua classificação é a absorção de água das peças cerâmicas, que resulta da presença de poros abertos. Esta depende, tanto das matérias primas utilizadas, quanto dos processos aplicados durante a fabricação (moagem, umidificação, conformação e queima, principalmente). Neste trabalho foram estudadas argilas vermelhas provenientes da Formação Corumbataí na região do Pólo Cerâmico de Santa Gertrudes (SP) e da Formação Tatuí na região de Cesário Lange (SP) procurando parâmetros indicativos que permitam uma seleção apropriada de matérias primas para realizar combinações adequadas das mesmas, para revestimentos via seca no primeiro caso, e blocos estruturais no segundo. Foram amostradas argilas com características diferentes, estudando a evolução da sinterização com o aumento da temperatura visando analisar a influencia da distribuição granulométrica e da mineralogia no comportamento apresentado. Com as mesmas amostras foram preparadas misturas calculando a contribuição de cada matéria-prima baseado na absorção de água de cada componente, prefixando a temperatura de queima e o valor de absorção de água. As diferenças entre os valores experimentais e os esperados foram analisadas visando entender as causas das variações. A distribuição de partículas resultante da moagem das matérias primas é influenciada fortemente por processos de intemperismo, sendo que, em termos gerais, as mais intemperizadas...

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

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This completion of course work has as its object of study the Bauxite Province of Paragominas regarded as the richest Amazon bauxite province and whose genesis is related to laterization processes responsible for the formation of mineral deposits of the Rondon Alumina Project, designed to assess areas in the southeast of Pará State, for mineral resources exploration of bauxite, which is the main source of aluminum in the country. Located in the region of Rondon do Pará - PA, the study area is geologically inserted in Lithostratigraphic Unit called Cobertura Laterítica Matura (Mature Lateritic Cover), formed by alteration of paleotropics Cretaceous siliciclastic rocks, and its geomorphology corresponds to a broad plateau with displays of representative profiles of the processes that acted in the region. In this context, the present research aims to characterize the geological evolution of the laterite profile, with detailed studies in the area, geological description of the formations from the bauxite surfaces, and mineralogical composition litochemical of different horizons that were correlated and deployed in an evolutionary model compatible with its traits. The data collected during the analysis subsidized metalogenetic understanding of the processes that acted in the enrichment of aluminum and iron as well as the redistribution of the latter modified profile. The results and information were embodied in the form of geological characterization of the different constituents of mineral associations of bauxite horizons, similarities or differences in both textural and structural aspects, in order to propose a evolutionary model with retaken of gibbsitization processes

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The Bom Futuro tin deposit is located in Ariquemes, north-central state of Rondônia. Since its discovery in the late 80s, the tin deposit of Bom Futuro has been explored and considered one of the leading Brazilian producers of cassiterite, exploring it mainly in secondary deposits (placers) in the vicinity of the hill Bom Futuro. The primary mineralization occurs in the contacts between quartz veins and pegmatites with the rocks of the hill and its exploitation has been the goal of new studies in the area. These bodies occur in all rock types of the hill, leading edges of hydrothermal alteration with each rock. The focus of the study is the characterization of hydrothermal alteration through the analysis of the edges of pegmatitic veins intruded on each of the main rock types found on the hill Bom Futuro, which are: biotite gneiss, biotite amphibolite, subvolcanic breccia, topaz leucogranite, topaz leucoriolito and micro melassienito porphyry. The analysis and comparison showed familiarities between the edges of alteration encountered, and possible subdivision into three main zones: the inner zone or the vein itself, intermediate zone or transition zone and the change zone where the passage of hydrothermal features to rocks features is gradual. The cassiterite and sphalerite were found scattered in three zones, however in larger quantities in the intermediate zone, near the contact

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The Roosevelt-Domain Aripuanã that by Filho et al 2004 is characterized by a metavolcanic sedimentary sequence, containing acidic to interemediary metavolcanic rocks and clastic and chemical sediments, deformed and metamorphosed at low grade, with U-Pb age of 1.743 +- 4 Ma, (by Granito Zé do Torno), and circumscribed bodies of granites late to post-orogenic (Aripuanã)...

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P-glycoprotein is an adenosine triphosphate (ATP)-driven drug efflux carrier responsible for transport of xenobiotics and multiple classes of drugs, many usually use in veterinary medicine. Encoded by MDR1 gene, also referred to as ABCB1, located on chromosome 14, is expressed in many tissues with secretory or excretory functions, such as liver, kidney and intestine, where it limits drug absorption from the gut and promotes drug excretion into the bile and urine of their substrates. In 2001, a 4 base pair gene deletion mutation in the canine MDR1 gene was identified as MDR1-1▲, ABCB1-1▲, MDR1 MDR1 nt 230 (del4) and associated with an non-functional Pglycoprotein. The clinical correlation is the (hyper) sensitivity of certain dogs breeds, mostly collies, to a few classes of drugs such as anticancer drugs (doxorubicin, vincristine, vinblastine), immunosuppressants (cyclosporine), antiparasitic drugs (ivermectin, moxidectin), steroids hormones (aldosterone, cortisol, dexamethasone), antimicrobial agents (tetracycline, doxycycline, levofloxacin, ketoconazole, itraconazole), analgesics (morphine, methadone), antidiarrheals (loperamide), antiepileptic agents (phenothiazine), cardiac drugs (digoxin, diltiazem, verapamil, talinolol) and others. Dogs with homozygous MDR1 nt 230 (del4) MDR1 mutations (MDR1 - / -) have a higher predisposition to intoxication with substrates of P-gp than heterozygous (MDR1 + / -) and these are more likely than dogs homozygous nonmutant (MDR1 +/ +). After the identification of nt230 (del4) mutation, several molecular techniques have been developed for identification of mutant animals as a diagnostic method. The importance of molecular diagnosis is, after the identification of mutant animals, establish treatment protocols safe, exclude this animals from reproduction (genetic selection program) and investigating the history of adverse drugs reactions... (Complete abstract click electronic access below)