Quartz Characteristics
Mostrando 1-12 de 68 artigos, teses e dissertações.
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1. Structural Characteristics of Lignite Char from Different Pyrolysis Reactors and the Influence on Their Gasification Reactivity
The gasification reactivity of coal char is affected by numerous experimental variables, and char structure is one of the dominant factors. In this work, Raman spectroscopy, powder X-ray diffraction (XRD), and N2 adsorption were used to investigate the physical and chemical structure of char prepared under different pyrolysis conditions. Three kinds of pyrol
Journal of the Brazilian Chemical Society. Publicado em: 2022
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2. Influence of the physical characteristics of sand and the crushed filler content on the properties of self-leveling mortars
Abstract The properties of self-leveling mortars (SLMs) in the fresh and hardened state are strongly affected by their formulation. In this study, the influence of three different quartz sands (different physical characteristics) was investigated in SLMs, as well as the replacement of these sands by crushed basalt filler. The tests performed were: spreading,
Cerâmica. Publicado em: 2021-06
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3. Evaluation of the use of silica-alumina refractory waste as a supplementary cementitious material
Abstract The use of supplementary cementitious materials (SMCs) is one of the three essential factors for the sustainability of the cement industry. To reduce CO2 emissions, several studies have introduced new methods for the utilization of industrial wastes such as the addition into cementitious materials. The objectives of this study were to chemically and
Cerâmica. Publicado em: 2021-06
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4. Mineralogical Characterization of Iron Ore Tailings from the Quadrilatero Ferrifero, Brazil, by Eletronic Quantitative Mineralogy
The mineralogical characterization studies search for the best processing route, with the lowest environmental impact, aiming to improve the use of mineral resources. The electronic quantitative mineralogy (EQM) provides quickly and accurately great information about the characteristics of these materials. This work aims to characterize iron ore tailings by
Mat. Res.. Publicado em: 02/12/2019
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5. Characterization of Brazilian Northeastern plastic clays
Resumo Argilas plásticas são uma das principais matérias-primas usadas em tecnologia cerâmica. No entanto, há uma escassez dessas argilas no mundo para o uso em tecnologia de porcelanas. O objetivo deste trabalho foi caracterizar argilas plásticas do nordeste brasileiro. Composições química e mineralógica, distribuição do tamanho de partículas,
Cerâmica. Publicado em: 14/11/2019
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6. Mineralogy and preliminary assessment of the potential uses of alluvial clays from Batouri (Eastern-Cameroon)
Resumo Este estudo teve como objetivo avaliar os usos potenciais de materiais argilosos aluviais de Batouri. Suas características mineralógicas, químicas e algumas físico-mecânicas são apresentadas, bem como algumas características de tijolos queimados em 900, 950, 1000, 1050 e 1100 °C. As matérias-primas consistiram de caulinita, quartzo, feldspato
Cerâmica. Publicado em: 15/08/2019
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7. Interações ambientais e resistência física de um depósito de resíduos finos da indústria de rochas ornamentais
RESUMO Embora vários trabalhos proponham aplicações para os resíduos finos gerados no beneficiamento de rochas ornamentais, ainda não há evidências das vantagens financeiras para tal aproveitamento. Assim, a descrição dos depósitos existentes, muitos deles construídos sem triagem ou qualquer medida de proteção ambiental, torna-se imprescindível
Eng. Sanit. Ambient.. Publicado em: 15/08/2019
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8. Microtensile bond strength of root canal dentin treated with adhesive and fiber-reinforced post systems
Abstract Nowadays, demand for esthetic restorations has risen considerably; thus, nonmetal esthetic posts made of either high-strength ceramics or reinforced resins, such as fiber-reinforced resin posts, have become more and more popular. Important characteristics of fiber-reinforced posts involve a modulus of elasticity similar to dentin and their ability t
Braz. oral res.. Publicado em: 01/07/2019
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9. Genesis and Classification of Nitisols from Volcano-Sedimentary Lithology in Northeastern Brazil
ABSTRACT On the southern coast of Pernambuco State (PE), Brazil, lithotypes of the Cabo Basin (volcanic and sedimentary rocks), in association with the relief, allow the determination of the dynamics of the formation of Nitossolos Háplicos (Nitisols), including those with high levels of exchangeable aluminum. The objective of this study was to evaluate the
Rev. Bras. Ciênc. Solo. Publicado em: 14/02/2019
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10. Potential Slow Release Fertilizers and Acid Soil Conditioners Obtained by One-Pot Mechanochemical Activation of Chrysotile:Cement Roofing Sheets with K2HPO4
Chrysotile:cement roofing sheets were milled with and without K2HPO4. As indicated by X-ray diffraction (XRD), the samples crystallinities were reduced with the increasing milling time. The same tendency was observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), with disaggregation of the chrysotile fiber bundles and forma
J. Braz. Chem. Soc.. Publicado em: 2019-02
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11. Influence of Diffusion Parameters on Electrical Characteristics of mc-Si Solar Cells with Aluminum and Phosphorus Diffusion Performed in the Same Thermal Step
The diffusion of phosphorus and aluminum in a single-step thermal process may reduce the production cost of multicrystalline silicon (mc-Si) solar cells. The goal of this paper is to analyze the influence of phosphorus diffusion parameters on the electrical characteristics of p-type mc-Si solar cells processed with a single-step diffusion of phosphorus and a
Mat. Res.. Publicado em: 10/01/2019
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12. Nepheline syenites to syenites and granitic rocks of the Itatiaia Alkaline Massif, Southeastern Brazil: new geological insights into a migratory ring Complex
ABSTRACT: The Itatiaia Alkaline Massif comprises some of the largest meso-cenozoic alkaline igneous occurrences in Brazil, covering over 215 km2 between the states of Minas Gerais and Rio de Janeiro. It appears as an elongated, 30-km long and 4.5-11.5-km wide SE-NW-trending body emplaced along accommodation zones of the Continental Rift of Southern Brazil, i
Braz. J. Geol.. Publicado em: 21/05/2018