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Mostrando 1-12 de 146 artigos, teses e dissertações.
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1. A química analítica aplicada aos estudos de pigmentos rupestres: uma revisão
Instrumental advances have been employed in the study of archeological remains such as prehistoric rupestrians paintings with the objective of chemically characterizing them in order to reconstruct the cultural technologies of a prehistoric human group and/or to support conservation science studies. The analytical techniques most commonly used in archaeometr
Química Nova. Publicado em: 2022
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2. The influence of separately and combined bentonite and kaolinite as binders for pelletization of NaA zeolite from coal fly ash
Abstract Pelletization of zeolitic materials is required to facilitate their practical industrial and commercial applications. Zeolite-NaA was synthesized from fly ash by the fusion method and shaped into spherical granules. Bentonite, kaolinite, and a combination of bentonite with kaolinite were tested as binders with different contents from 5 to 10 wt%. Th
Cerâmica. Publicado em: 2022
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3. Microbial activity and studies on excavated megalithic micaceous potsherds from Peninsular India
Abstract The abundantly available mica flakes were added in raw materials to manufacture pottery in Central Peninsular India during the early Iron Age (700-300 BCE) for storage and glittering. The micaceous potsherds from the excavated megalithic site of Nagpur were studied for their composition, manufacturing techniques, microstructural features, microbial
Cerâmica. Publicado em: 2021-06
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4. Expansibility of vermiculite (Santa Luzia, Brazil) irradiated with microwave
Abstract The effect of microwave heating on the expansion of vermiculite was studied at a level of 700 W for 4 min exposure time and compared with raw vermiculite. In this study, the characterization of vermiculite from a mine in the northeast region of Brazil was performed using thermogravimetry, N2-adsorption, cation exchange capacity, X-ray powder diffrac
Cerâmica. Publicado em: 2021-06
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5. Effect of pH level and calcination on the production of calcium phosphates by acidic route of wet precipitation
Abstract Multiphasic calcium phosphate powders were synthesized by the acidic route, using lactic acid as a chelating agent that allows the production of a stable and rich solution of calcium and phosphate ions at room temperature. After pH adjusting, without varying the concentrations of precursor solution, XRD and FTIR analyses showed different CaP phases
Cerâmica. Publicado em: 2021-06
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6. Synthesis and characterization of niobium-doped fish scale-derived hydroxyapatite by physical ultrasound interference
Abstract Fish scales of the Arapaima gigas (pirarucu) species were heat-treated to obtain natural hydroxyapatite (HAp), and it was doped with niobium (Nb) by physical ultrasound interference to confirm an effective route to the production of Nb-doped HAp powders. The effect of ultrasound application on doping was investigated. The structure of the powders wa
Cerâmica. Publicado em: 2021-03
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7. DETERMINAÇÃO DE FÓSFORO EM PALEOSSEDIMENTOS EMPREGANDO ESPECTROMETRIA DE FLUORESCÊNCIA DE RAIOS-X PORTÁTIL
Phosphorus (P) is an important chemical marker of the past human presence, because, besides indicates the localization of possible archaeological sites, also, contributes to clarify doubts regarding to origin, duration and to specific functions that were developed in them. The present study aimed to obtain a simple, accurate, fast and non-destructible analyt
Quím. Nova. Publicado em: 2021-02
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8. Elemental Composition of Particulate Matter in the Southeastern Brazilian Ceramic Pole by Synchrotron Radiation X-ray Fluorescence Technique (SR-XRF)
In the present study, the elemental content of the particulate matter PM2.5 (particulate matter with diameters lower than 2.5 µm) and PM10 (particulate matter with diameters lower than 10 µm) of the Brazilian city of Rio Claro (SP) were analyzed by synchrotron radiation X-ray fluorescence (SR-XRF) in the Brazilian Synchrotron Light Laboratory (LNLS). A fra
J. Braz. Chem. Soc.. Publicado em: 2020-06
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9. Potassium recovery from Brazilian glauconitic siltstone by hydrothermal treatments
Abstract Silicate rock Verdete, collected in the central region of Minas Gerais state (Brazil) and composed mostly of micas (glauconite and muscovite) and tectosilicates (K-feldspar and quartz), was hydrothermally treated with several reactants in order to release and recover potassium. The hydrothermal products were characterized by flame photometry, XRD, X
REM, Int. Eng. J.. Publicado em: 2020-06
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10. INFLUÊNCIA DA COMPOSIÇÃO DOS NANOFIOS PT-IR/C NA ATIVIDADE CATALÍTICA FRENTE A OXIDAÇÃO ELETROQUÍMICA DE ETANOL EM MEIO ÁCIDO
Carbon-supported platinum-iridium nanowire-shape electrocatalysts containing 20% of metallic loading were synthesized by chemical reduction method using formic acid as a reducing agent and tested towards the oxidation of ethanol in acidic medium. The developed electrocatalysts were synthesized with the following compositions: Pt0.9Ir0.1/C, Pt0.8Ir0.2/C, Pt0.
Quím. Nova. Publicado em: 2020-02
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11. Aplicações da arqueometria no mobiliário de São Paulo do século XVIII: análises indiciárias e contextualização histórica
RESUMO Neste artigo, são apresentados os resultados dos exames arqueométricos de Física aplicada sobre duas peças de mobiliário do acervo do Museu Paulista, uma arca-cofre e uma cadeira de couro de sola feitas por volta do século XVIII. As técnicas de análise utilizadas foram o ED-XRF e o imageamento com fluorescência de luz ultravioleta. As anális
An. mus. paul.. Publicado em: 05/12/2019
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12. Assessment of sulfamethoxazole adsorption capacity on Pirangi clay from the State of Sergipe, Brazil, modified by heating and addition of organic cation
Resumo O sulfametoxazol (SMX) é um antibiótico amplamente usado no tratamento de doenças e infecções e é frequentemente detectado em ecossistema de águas superficiais. Assim, este trabalho avaliou a capacidade de remoção deste antibiótico de sistemas aquosos utilizando argila Pirangi (PIR) do estado de Sergipe (Brasil). Amostras de argila Pirangi f
Cerâmica. Publicado em: 14/11/2019