Gneiss
Mostrando 1-12 de 45 artigos, teses e dissertações.
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1. Comparative evaluation of three classical sizing methods of vibrating screens
Abstract The sizing of vibrating screen machines can be done by various methods, most of them based on the classic method of Allis Chalmers (ACM). Due to the wide diffusion and applicability, the Peter King (PKM) and Karra (KM) methods present great technical relevance as well. The objective of this study was to evaluate and compare the results of the screen
REM - International Engineering Journal. Publicado em: 2022
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2. Mineralogical characterization of copper lateritic ore from the Furnas deposit - Carajás, Brazil
Abstract Furnas is a small and not well-known copper sulfide deposit in the northern Carajás mineral province (Pará State, Brazil). Mineralogical and geochemical studies were performed on three weathered samples in order to verify the presence of copper in the lateritic minerals. According to these Cu-bearing minerals (malachite, e.g.), the weathered ore c
REM, Int. Eng. J.. Publicado em: 2020-09
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3. U-Pb SHRIMP dating of basement rocks of the Iriri-Xingu domain, Central Amazonian province, Amazonian craton, Brazil
Abstract The Iriri-Xingu domain, located in the central part of the Amazonian craton, consists of extensive occurrences of Paleoproterozoic volcanic rocks and granites with published ages of ca. 1990 to 1840 Ma, which show a strong crustal contribution for their magmas. Exposures of basement rocks are small and rare. Samples from two areas were dated in this
Braz. J. Geol.. Publicado em: 21/10/2019
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4. Análise da influência do tipo de agregado miúdo nas características e dosagem de argamassas mistas
Resumo As argamassas de revestimento e assentamento de alvenaria com uso de areia artificial de britagem tem se tornado uma alternativa viável nos últimos anos, contudo têm-se grandes divergências quanto a preceitos de dosagem adequada para esses materiais. Diante disso, este trabalho objetiva estudar argamassas mistas de revestimento e assentamento de a
Ambient. constr.. Publicado em: 03/10/2019
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5. Landslides Zonation Hazard: relation between geological structures and landslides occurrence in hilly tropical regions of Brazil
ABSTRACT This paper presents a new approach of landslides zonation hazard studies, based on an integrated study of structural data along with geomorphological and external factors, in a hilly regions of Brazil, covered by a tropical humid rain-forest, called Serra do Mar. The Serra do Mar consists of a hilly region along the east coast of Brazil, with high s
An. Acad. Bras. Ciênc.. Publicado em: 31/08/2017
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6. Microwave Acid Extraction to Analyze K and Mg Reserves in the Clay Fraction of Soils
ABSTRACT: Extraction of K and Mg with boiling 1 mol L-1 HNO3 in an open system for predicting K and Mg uptake by plants is a method of low reproducibility. The aim of this study was to compare the extraction capacity of different acid methods relative to hydrofluoric acid extraction for K and Mg. A further objective was to develop a chemical extraction metho
Rev. Bras. Ciênc. Solo. Publicado em: 15/12/2016
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7. Rare Earth Element Concentrations in Brazilian Benchmark Soils
ABSTRACT: Studies regarding background concentrations of rare earth elements (REEs) are scarce and have mainly focused on a limited number of soil types from the northern hemisphere. The aim of this study was to determine REE concentrations in thirty-five benchmark soils of Brazil. Composite soil samples were taken from areas under native vegetation or with
Rev. Bras. Ciênc. Solo. Publicado em: 15/12/2016
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8. Avaliação do comportamento solo-estrutura de elementos de fundação tipo sapata estaqueada / Assessment of the behavior of soil-structure foundation elements like piled footing
This work aims to study the behavior and interaction between soil, shallow footing and pile, based on the implementation and monitoring of four direct load tests performed on: a single shallow footing, a shallow footing with one pile, a shallow footing with four piles and a pile alone. During the load tests, vertical displacements were monitored at different
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 28/02/2012
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9. Survey and study of graphite occurrences in the Aracoiába-Baturité graphite bearing District, CE / Levantamento e estudo das ocorrências de grafita do Distrito Grafitífero Aracoiába-Baturité, CE
The Aracoiába-Baturité Graphite-bearing District has graphitic gneiss deposits (disseminated ore) and vein (solid ore) with different genetic origins and their own physical characteristics and geological environments. The graphite gneiss ore is of sedimentary, syngenetic origin, with 1.5% to 8% C content, which is distributed along two long parallel belts,
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 23/03/2011
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10. Resistência ao arrancamento de grampos em solo residual de gnaisse / Pullout resistance of nails in gneiss residual soil
A adoção da técnica de solo grampeado no projeto de contenção de taludes ou escavações vem sendo cada vez mais freqüente, com isto se faz necessário um maior numero de estudos sobre a estimativa da resistência ao arrancamento (qs) em função de parâmetros de ensaios de campo para os mais variados tipos de solos brasileiros. O objetivo desta pesqu
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 13/12/2010
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11. Influência de variáveis de compactação na estrutura dos solos: caracterizações geotécnica, química, mineralógica e microestrutural / Influence of laboratory compaction variables in soils structure: geotechnical, chemical, mineralogical and microstructural characterizations
This research addressed the effect of laboratory methods of static and dynamic compaction on compaction parameters, mechanical strength and compressibility of three gneiss residual soils (two young and one mature soils) and two granite residual soils (one young and one mature soils) from the Minas Gerais State, Brazil. Disturbed soils samples were collected,
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 09/12/2010
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12. Oligochaetas edáficos em solos sob sistema de manejo a pleno sol e agroflorestal e vermicompostagem associada com pós de rochas / Edaphic oligochaetes in soils sun- and agroforestry-coffee management and vermicomposting associated with powdered rock
Os Oligochaetas edáficos atuam em vários processos fundamentais para a manutenção da fertilidade e qualidade dos solos de agroecossistemas. As práticas agrícolas, condições climáticas e as características do solo afetam a população de oligochaetas edáficas. Atualmente, frente aos problemas como o decréscimo de qualidade do solo, da água e das
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 26/07/2010