Inorganic Oxides
Mostrando 13-24 de 31 artigos, teses e dissertações.
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13. Desenvolvimento de microemulsões contendo fotoprotetores inorgânicos nanoparticulador
The inorganic actives, represented mainly by microfine zinc oxide and titanium dioxide, have shown great potential to protect against large UV spectrum. The aim of this study is the development, characterization and analysis of stability in the short term of microemulsions containing inorganic fotoprotection agents. The microemulsions identified by the phase
Publicado em: 2008
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14. Sintese de materiais nanoestruturados MS IND. 2 (M = Mo, W) com alta pureza de fase e morfologia / Synthesis of MS IND. 2 (M = Mo, W) nanostructured materials with high purity of phase and morphology
The main of this Dissertation is the preparation of nanostructured WS2 and MoS2 from a template reaction with the respective nanorods oxides. Molybdenum oxide nanorods with diameters around 100 nm and microscale lengths were prepared from MoO3·2H2O via a one step solvothermal reaction. The formation of MoO3 rods proceeds in acidic media at 180 °C. The oxid
Publicado em: 2008
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15. Perovskitas contendo lantânio, ferro e cobalto - melhoramento de propriedades texturais via síntese por nanomoldagem e avaliação como catalisadores na redução de NO com CO
Mixed oxides with perovskite structure have high potential as catalysts in gas depollution processes and particularly in the abatement of nitrogen oxides (NOx). Such solids could be considered as a promising alternative for the replacement of noble metals based catalysts, whose use is predominant. Great flexibility of composition, easy synthesis, low cost an
Publicado em: 2008
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16. Síntese e caracterização de materiais nanoporosos para pirólise catalítica de óleos pesados
The present work reports the study of nanoporous structures, aiming at their use in research directed to the current demand of the petroleum industry to value heavy oil. Initially, two ways were chosen for the synthesis of porous structures from the molecular sieves of type Si-MCM-41. In the first way, the structure MCM-41 is precursory for heteroatom substi
Publicado em: 2008
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17. Emissões de CO2, NOx e N2O em solos sob diferentes cultivos na região do cerrado / CO2, NOx and N2O emissions from soils to the atmosphere under differente cropping systems in the cerrado region
The objective of the study was to evaluate the CO2, NO, N2O emissions from Oxisols (Latossolos) under different no-till cropping systems in the Cerrado region (Central Brazil). The results are presented in three chapters. Chapter 1 presents a study on the effects of increasing doses of nitrogen fertilizer on the fluxes of trace gases along the crop cycle of
Publicado em: 2008
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18. Preparation, characterization and aplication of anodes of nominal composition Ti/RuyTi(1-y-x)SnxO2 in the degradation electrochemical of chlorophenols / Preparação, caracterização e aplicação de ânodos de composição nominal Ti/RuyTi(1-y-x)SnxO2 na degradação eletroquímica de clorofenóis
In this work oxides electrodes of nominal composition Ti/RuyTi(1-y-x)SnxO2 were prepared by thermal decomposition (400 °C) by three different routes: Traditional Method using inorganic precursors dissolved in either Isopropanol (MT/ISO) or a solution of HCl 1:1 (v/v) (MT/HCl) and the Polymeric Precursors Method (MPP).Oxides coatings were characterized by Sc
Publicado em: 2007
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19. Estudo da influência da adição de polímeros precursores cerâmicos na sinterização de SiC e Al2O3 / Influence of the addition of precursor polymers on sintering SiC and AI2O3 ceramics
Neste trabalho foram avaliados os efeitos da adição de polímeros precursores na sinterização, microestrutura, dureza e na tenacidade à natura de materiais cerâmicos à base de carbeto de silício e de AI2O3. As matérias-primas cerâmicas foram caracterizadas por análise semi-quantitativa por espectrometria de fluorescência de raios X, difração po
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 14/03/2006
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20. Adsorção de glifosato sobre solos e minerais
Glyphosate, an enzyme inhibitor herbicide, has been widely used around the world in agriculture. Dr. John Franz from Monsanto Corporation (USA) discovered glyphosate in 1970. It has been showed that glyphosate is strongly adsorbed by inorganic soil components especially aluminium and iron oxides, and the phosphate group is involved in this interaction. The i
Química Nova. Publicado em: 2006-07
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21. Development of alternative catalysts for the reduction of nitrogen oxides with carbon monoxide in plants of fcc. / Desenvolvimento de catalisadores alternativos para a redução de óxidos de nitrogênio com monóxido de carbono em plantas de fcc.
Recentemente, o desenvolvimento de tecnologias eficientes visando à redução dos óxidos de nitrogênio, em regeneradores de unidades de craqueamento catalítico em leito fluidizado, tem se tornado uma grande preocupação, devido aos rigorosos limites de emissão impostos pela legislação ambiental. Como a maioria das refinarias utiliza promotores de com
Publicado em: 2006
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22. Glass passivation in power rectifiers. / Passivação a vidro de junções semicondutoras em dispositivos de potência.
The search for better electrical properties, new passivating materials for semiconductors junctions and the process of obtaining those ones have being studied intensively in the latest decades. There are two types of passivation layers: thick film and thin film. The first one is obtained by the deposition of silicon oxides, silicon nitride or silicon carbide
Publicado em: 2006
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23. Ethanol Electrooxidation with dimensionally stable anodes, DSA®, in NaCl medium / Eletrooxidação do etanol na presença de cloreto de sódio em eletrodos de óxidos de rutênio e irídio
In this work, it was investigated the electrocatalytic properties of oxides electrodes denominated dimensionally stable anodes, DSA®, in NaCl medium, applying them for ethanol oxidation. For this propose, many experimental parameters nave been investigated: the modulator oxide, changes in the preparation method of the electrode and pH changes of the solutio
Publicado em: 2005
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24. Obtenção de matrizes inorganicas macroporosas via cristais coloidais e sua posterior aplicação na preparação de compositos
This work reports the preparation of macroporous inorganic materials by different methods involving colloidal crystals. The emulsion templating method employs emulsion droplets as porous templates around which the oxide precursor is deposited through a sol-gel process. In the latex templating method, latex spheres are employed as porous templates, also assoc
Publicado em: 2003