Iron Oxides
Mostrando 37-48 de 151 artigos, teses e dissertações.
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37. Iron oxides dynamics in a subtropical Brazilian Paleudult under long-term no-tillage management
Replacing conventional tillage (CT) with no-tillage (NT) management alters the pedoenvironment and the rate of topsoil processes, with possible effects on dissolution processes associated with iron oxides and therefore soil mineralogy. This study aimed to determine the effect of NT on the content and distribution of types of iron oxides in a Rhodic Paleudult
Sci. agric. (Piracicaba, Braz.). Publicado em: 2013-02
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38. Óxidos de ferro e suas aplicações em processos catalíticos: uma revisão
A review of most of the reported studies on the use of iron oxides as catalyst in specific processes, namely Haber-Bosch reaction, Fischer-Tropsch synthesis, Fenton oxidation and photolytic molecular splitting of water to produce gaseous hydrogen, was carried out. An essential overview is thus presented, intending to address the fundamental meaning, as well
Quím. Nova. Publicado em: 2013
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39. DinÃmica de fÃsforo em manguezais impactados por Ãguas residuÃrias no Estado do CearÃ. / Dynamics of phosphorus in mangroves impacted by the state of CearÃ.
Recent studies demonstrated the efficacy of mangrove retaining nutrients and, in particular, the ability of the mineral component of the buffer in its high soil phosphorus levels. In general, the mangroves have been considered as important sinks of nutrients due to its high capacity purification of effluents. However, depending on the geochemical conditions
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 26/06/2012
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40. Resposta da cultura do milho aos fertilizantes fosfatados e nitrogenados revestidos com polímeros / Response of maize to polymer-covered phosphate and nitrogen fertilizers
The effective use of fertilizers, besides resulting in greater yield, can reduce production costs, with positive results in the end of the cropping season. Soil correction and fertilization in intensive maize production systems represent, on average, 40% to 45% of the production cost. Phosphorus is considered as a nutrient with low absorption by plants due t
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 06/01/2012
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41. PHOSPHORUS INCORPORATION INTO MULTIWALLED CARBON NANOTUBES / INCORPORAÇÃO DE FÓSFORO EM NANOTUBOS DE CARBONO DE PAREDES MÚLTIPLAS
The thesis addresses the incorporation of phosphorus atoms into the structure of multi-walled carbon nanotubes (MWCNTs) grown by the Spray Pyrolysis method. To this end, the concentration of ferrocene in the precursor was fixed in 2,0 wt %, while the concentration of triphenylphosphine (Ph3P) was varied from 0,15 to 0,65 wt %. Scanning and transmission elect
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 25/08/2011
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42. 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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43. Alojamento e deformação de plútons graníticos da extremidade nordeste da Suíte Intrusiva Cunhaporanga (Domínio Apiaí - Faixa Ribeira, PR) / Emplacement and deformation of granitic plutons from northeast of Cunhaporanga Intrusive Suite (Apiaí Domain - Ribeira Belt, PR)
Granite plutons located on the northeast of Cunhaporanga Intrusive Suite (Patrimônio Santo Antônio, Ouro Verde, São Domingos and Santa Rita) are emplaced into low grade metasedimentary rocks (Itaiacoca Group) of the Apiaí Domain (Ribeira Belt). Most of these plutons are isotropic with pinkish to grey colors and their compositions vary from monzogranite t
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 29/04/2011
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44. Photocatalytic discoloration of reactive blue 5g dye in the presence of mixed oxides and with the addition of iron and silver
This work reports the use of cerium - titania - alumina - based systems modified with Ag and Fe by the wetness impregnation method for the discoloration of blue 5G dye. The techniques employed to characterize the photocatalysts were: temperature - programmed reduction (TPR), X - ray diffraction (XRD), specific surface area, average pore volume, and average p
Brazilian Journal of Chemical Engineering. Publicado em: 2011-09
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45. Revisão de intemperismo de micas.
ABSTRACT: The micas are rock forming mineral of the phyllosillicates group. The weathering of these minerals is fundamental in the understanding of potassium, silicon and magnesium liberation processes to the soil. the existent studies shown that the main factors that control the micas weathering are the pH of the solutions, the temperature, the size of the
Planaltina. Publicado em: 2011
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46. Pigmentos de pinturas rupestres pré-históricas do sítio Letreiro do Quinto, Pedro II, Piauí, Brasil
The Letreiro do Quinto rock shelter is located in the rural area of the city of Pedro II, Piauí, Brazil. The sandstone walls of the shelter are covered with prehistoric rupestrian paintings, painted in patterns of yellow and light and dark red hues. The chemical-mineralogical characterization of the prehistoric pigments was made with energy dispersive spect
Química Nova. Publicado em: 2011
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47. Controle na distribuição das lateritas e saprolitos de alto teor no depósito de níquel laterítico do Jacaré, Distrito de Carajás, Brasil
The Jacaré world class nickel lateritic deposit (495Mt @ 1,19% Ni) is positioned about 52 Km NNE straight line from São Félix do Xingu/PA State - Carajás Mineral Province. The deposit occurs in essentially dunitic and gabbroic rocks magmatically layered with subordinated peridotites and pyroxenites levels. The saprolitic zones host the main Ni ores and t
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 2011
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48. Preparação, caracterização e avaliação de óxidos de ferro e cobalto suportados em carvão ativado polimérico como catalisador na reação de desidrogenação do etilbenzeno / Preparation, characterization and evaluation of iron oxides and cobalt supported on activated carbon and polymeric catalysts for the dehydrogenation of ethylbenzene
Neste trabalho foram sintetizados catalisadores suportados em carvões ativados, que foram obtidos por meio da carbonização de uma matriz polimérica. O precursor do carvão ativado foi o copolímero de estireno e divinilbenzeno sulfonado, que foi sintetizado por meio de polimerização em suspensão, na presença de diluentes inertes para a produção de
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 09/02/2010