Carbonates
Mostrando 13-24 de 91 artigos, teses e dissertações.
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13. Glass Microbeads in Analog Models of Thrust Wedges
ABSTRACT Glass microbeads are frequently used in analog physical modeling to simulate weak detachment zones but have been neglected in models of thrust wedges. Microbeads differ from quartz sand in grain shape and in low angle of internal friction. In this study, we compared the structural characteristics of microbeads and sand wedges. To obtain a better pic
An. Acad. Bras. Ciênc.. Publicado em: 2017-03
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14. GIS-based analysis of geo-resources and geo-hazards for urban areas - the example of the northern periphery of Belo Horizonte (capital of Minas Gerais, Brazil)
Abstract Easily understandable thematic maps of geo-scientific parameters are important for land use decision making. If several parameters are relevant and have to be compared, it is important that they are consistent with each other, available at the same spatial range and detail and normed to a common data range. In the current study, geological and topog
REM, Int. Eng. J.. Publicado em: 2017-03
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15. Barium and its Importance as an Indicator of (Paleo)Productivity
ABSTRACT Barium (Ba) is a trace element which occurs predominantly as barite mineral (BaSO4) in the marine environment. Previous work suggests that barite concentrations are related to the organic carbon flux and marine biological debris in the water column suggesting a direct or indirect involvement in the marine biological cycling. In addition, barite has
An. Acad. Bras. Ciênc.. Publicado em: 2016-12
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16. Genesis and Classification of Soils Containing Carbonates in a Toposequence of the Bambuí Group
ABSTRACT The Bambuí Group, formed from siliciclastic sediments deposited on an extensive epicontinental platform at the end of the Neoproterozoic era, is characterized by limestones with fine to very fine texture. Limestone-derived soils in the southeast of Tocantins state, Brazil, are less notorious than similar soils in other regions of Brazil and their c
Rev. Bras. Ciênc. Solo. Publicado em: 29/08/2016
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17. Acritarchs of the Ediacaran Frecheirinha Formation, Ubajara Group, Northeastern Brazil
We report for the first time the occurrence of organic-walled microfossils in Ediacaran limestones and marls of the Frecheirinha Formation, Ubajara Group, and the first Precambrian acritarchs so far reported for northeastern Brazil. The assemblage of the Frecheirinha Formation represents a low-diversity microflora comprising Leiosphaeridia, Lophosphaeridium
An. Acad. Bras. Ciênc.. Publicado em: 2015-06
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18. Química e sustentabilidade: novas fronteiras em biocombustíveis
This contribution discusses the state of the art and the challenges in producing biofuels, as well as the need to develop chemical conversion processes of CO2 in Brazil. Biofuels are sustainable alternatives to fossil fuels for providing energy, whilst minimizing the effects of CO2 emissions into the atmosphere. Ethanol from fermentation of simple sugars and
Quím. Nova. Publicado em: 2013
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19. Avaliação do desempenho de depressores na flotação direta do minério fósforo-uranífero de Itataia
O Brasil consome enormes quantidades de fertilizantes a base de fósforo devido às características do solo, pobre em nutrientes principais, e à grande produção agrícola. Apesar do grande consumo, a produção de produtos fosfatados é insuficiente para atender a demanda interna. Uma das razões é que os depósitos fosfáticos brasileiros não apresent
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 30/08/2011
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20. Caracterização e separabilidade de agregados miúdos produzidos a partir de resíduos de construção e demolição. / Technological characterization and separability studies on fine aggregates produced from construction and demolition waste.
The current demand for recycling on construction is due to the increasing consumption of aggregates, the exhaustion of deposits close to large cities as well as the ban on inert materials dumping in landfills and the rising cost of its disposal. Moreover, with the remarkable increasing on construction activities in many countries, the management of Construct
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 26/08/2011
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21. Influência da adição de um fundente sintético no mecanismo de coloração final de revestimentos cerâmicos / The influence of the addition of a synthetic flow in the final color mechanism of ceramic tiles
The presence of iron oxide in ceramic tile mass contributes to the reddish color firing of the products leading to a lower aggregate value, not to be regarded as a "noble" ceramic. However, the use of raw materials with low levels of iron oxides (Fe2O3) is economically unfeasible in Brazil, since most of the deposits have iron compounds as mineral component.
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 12/08/2011
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22. Investigação experimental sobre a geração, visualização e avaliação da condutividade de fraturas ácidas em carbonatos microbiais / Experimental investigation of the building, visualization and evaluation of acid fracture conductivity on microbial carbonates
O sucesso da estimulação por fraturamento hidráulico ou ácido é dependente da geração de condutividade. No fraturamento hidráulico sustentado, a condutividade é gerada pela introdução de uma quantidade significativa de um agente de sustentação granular e praticamente esférico. No fraturamento ácido, a condutividade é gerada por irregularidade
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 08/07/2011
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23. Efeito de metais de transição sobre a polarização espontânea na estrutura cristalina de nanopós da família tungstênio bronze
This work aimed the study of the effect of transition metals (Ni, Fe, Co) on the spontaneous polarization of the ferroelectric oxides of tetragonal tungsten bronze (TTB)-type structure of potassium strontium niobate (KSr2Nb5O15) and of the KSr2(FeNb4)O15-d, KSr2(NiNb4)O15-d and KSr2(CoNb4)O15-d solid solutions. All systems investigated were prepared by mecha
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 28/02/2011
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24. Macrobenthic community structure in a Brazilian chocked lagoon system under environmental stress
Saquarema-Jaconé lagoonal system (SJLS) comprises a sequence of five interconnected shallow brackish lagoons with access to the sea by a single permanent tidal channel. It is a eutrophic system, receiving constant input of organic load from its urbanized catchments. The relationship between several environmental variables and the spatial-temporal distributi
Zoologia (Curitiba). Publicado em: 2011-06