Topaz
Mostrando 1-11 de 11 artigos, teses e dissertações.
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1. Aquamarine from Massangana batholith, Rondônia State: mineral chemistry and fluid inclusion data
Abstract Beryl is usually found in granite-pegmatite systems. The addition of chromophore elements (V, Cr, Mn, Fe) into the crystalline structure favors color changes in beryl and thus generates some of the world’s expensive gems such as emerald, morganite, heliodor and aquamarine. The Massangana polyphasic batholith is a well-known cassiterite, wolframite
REM, Int. Eng. J.. Publicado em: 2020-09
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2. A cathodoluminescence-assisted LA-ICP-MS study of topaz from different geological settings
ABSTRACT: In this study, the crystallization dynamics and the fingerprints of two topaz crystals from the Ouro Preto region (Brazil), two from the Eastern Brazilian Pegmatite Province (EBPP), one from the Western part of the United States (US) and one from Pakistan were characterized. The combination of scanning electron microscope-cathodoluminescence (SEM-C
Braz. J. Geol.. Publicado em: 2018-01
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3. Potencial impacto das mudanças climáticas nas perdas de solo e água na microbacia do córrego Jaqueira, Alegre - ES. / Potential impact of climate change on soil loss and water in the watershed of the córrego Jaqueira, Alegre - ES.
O controle do processo erosivo requer o entendimento das interações complexas entre os processos químicos e físicos do solo, além dos hidrológicos e meteorológicos. Diversos modelos matemáticos vêm sendo desenvolvidos e aperfeiçoados com o objetivo de prever a magnitude das perdas de solo por erosão, como o Water Erosion Prediction Project (WEPP).
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 22/07/2010
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4. Pequenos polarons ligados e centros de cor em topázio
In the present work we studied the color beneficiation processes of colorless topaz, an abundant gemstone in Brazil. Blue topaz is the most internationally traded gemstone in the gem and market, reaching about 100 million carats per year. Almost 100% of blue topaz received some treatment to improve the color that, generally, involves some type of irradiation
Publicado em: 2010
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5. Estudio mineralógico, microtermométrico y aspectos estructurales de la mineralización de topacio imperial de Antônio Pereira, Distrito de Ouro Preto (Minas Gerais) - Brasil
The occurrences of imperial topaz in the Antonio Pereira mine, Ouro Preto, Minas Gerais, are associated with the metamorphic carbonate rocks of the Minas Supergroup. The crystals have densities varying from 3.46 to 3.58. The parameters of the unitary cells obtained were: 4.658 to 4.663Å (a o), 8.823 to 8.832Å (b o), 8.382 to 8.389Å (c o), and 344.65 to 34
Rem: Revista Escola de Minas. Publicado em: 2009-03
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6. Structural characterization of mullites synthesized by thermal decomposition of topaz
The structure of mullite obtained by thermal decomposition of topaz at 1340 °C and after additional thermal treatment at 1600 °C was characterized by 29Si and 27Al MAS NMR spectroscopy and x ray diffraction. No amorphous phase was detected by these techniques. The 29Si MAS NMR spectra of the mullite samples showed four resonance peaks at -81, -86, -90 and
Materials Research. Publicado em: 2007-03
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7. COMPORTAMENTO FISIOLÃGICO E PRODUTIVIDADE DE CAFEEIRO ARÃBICA - CULTIVAR TOPÃZIO MG 1190 - SOB DIFERENTES ORIENTAÃÃES CARDEAIS / Physiological behavior and productivity of arabica coffee - MG cultivar topaz 1190 - cardinals under different guidelines
The coffee plant study of phenological development and productivity using TOPAZIO MG 1190 variety, was realized in different cardinal directions (N-S, NE- SW, E-W, and SE-NW) in the region of PatrocÃnio, Minas Gerais. The evaluations were initiated in October/2002, when the plants were two years old and, since this time, every month, on the both side of pla
Publicado em: 2007
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8. Caracterização das rochas vulcânicas e plutônicas félsicas e intermediárias do Alvo Estrela (Cu-Au), Serra de Carajás, Pará
The Estrela Cu-Au deposit is situated in the Serra do Rabo, at the easternmost part of Carajás shear zone, at the Serra dos Carajás region. It is hosted by altered andesites and gabbros and rhyolites of the Grão Pará Group, Itacaiunas Supergroup, formed at 2.76 Ga (Sm-Nd isochronic age) cut by Paleoproterozoic porphyritic quartz diorite, orthoclase-albit
Publicado em: 2006
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9. Desvendando a cor e a termoluminescência do topázio: um estudo dos defeitos e processos termicamente e opticamente estimulados no cristal natural / Unraveling the color of topaz and thermoluminescence: a study of defects and thermally and optically stimulated processes in natural crystal
O topázio [Al2SiO4(F,OH)2] é mais freqüentemente encontrado na natureza na forma incolor, a partir do qual gemas azuis vêm sendo produzidas comercialmente através da aplicação de radiação ionizante seguida de tratamentos térmicos. O topázio também exibe termoluminescência (ou luminescência termicamente estimulada) relativamente intensa, que é
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 06/06/2001
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10. HOW THE BALLOON PUMP WAS CONCEIVED A Personal Reminiscence
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11. Quantitative analysis of the formation and diffusion of A1-adenosine receptor-antagonist complexes in single living cells
The A1-adenosine receptor (A1-AR) is a G protein-coupled receptor that mediates many of the physiological effects of adenosine in the brain, heart, kidney, and adipocytes. Currently, ligand interactions with the A1-AR can be quantified on large cell populations only by using radioligand binding. To increase the resolution of these measurements, we have desig
National Academy of Sciences.