Nb2o5
Mostrando 1-12 de 280 artigos, teses e dissertações.
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1. Quando se deve repetir endoscopia em pacientes com dispepsia?
Pacientes com dispepsia já investigada com endoscopia podem necessitar de nova endoscopia nas seguintes situações:
– Controle de erradicação de H. pylori em pacientes com úlcera gástrica ou duodenal, pelo menos 4 semanas após o tratamento de erradicação;
– Controle de cicatrização de úlcera gástrica, após 8 a 12 semanas de u
Núcleo de Telessaúde Rio Grande do Sul. Publicado em: 12/06/2023
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2. Qual o período ideal para gestante realizar tratamento odontológico?
Para o tratamento odontológico da gestante recomenda-se que o dentista esteja atento ao período gestacional e ao problema odontológico a ser tratado. O período ideal e mais seguro para o tratamento odontológico é durante o segundo trimestre da gestação
. No entanto, se a gestante necessitar de tratamento de urgência e emergência, esses dev
Núcleo de Telessaúde Amazonas. Publicado em: 12/06/2023
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3. Metal-Supported Niobium Catalysts Investigation for Conversion of Bio-Renewable Glycerol to Organic Compounds
The glycerol oxidative dehydration to organic compounds, especially acrolein and acrylic acid, was studied over vanadium, molybdenum, and cobalt oxides supported on niobium oxide and niobium phosphate catalysts. At 300 °C, the glycerol conversion was 100% over all catalysts tested, and acrolein was the main product observed, without significant deactivation
Journal of the Brazilian Chemical Society. Publicado em: 2022
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4. Fast Catalytic Pyrolysis of Tetradecanoic Acid: Formation of Ketones as Intermediate Compounds in the Production of Hydrocarbons
This work aimed to compare two different catalysts in the production of a long chain ketone, intermediate in the production of hydrocarbons, during pyrolysis of tetradecanoic acid as a model fatty acid. The studied variables were the temperature, 450 and 600 ºC, and catalysts, γ-Al2O3 and Nb2O5, the latter has never been studied under such conditions. Pyro
Journal of the Brazilian Chemical Society. Publicado em: 2022
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5. Catalytic Transformation Conditions of Ethanol on Dealuminated BEA Zeolites
Catalysis is an important tool in obtaining a range of derivative products from renewable sources, such as ethanol. Solid-state dealumination using ammonium hexafluorosilicate on the BEA zeolite under the treatment at temperature of 190 °C, 70 mol% dealumination in the presence of humidity and washing with buffer solution at 25 °C generated larger pores. T
J. Braz. Chem. Soc.. Publicado em: 21/10/2019
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6. Obtaining Composites Powders of Al2 O3 / Ni and Al2 O3 / Nb by Mechanical Alloying
Mechanical alloying (MA) can be highlighted among the various methods and powder processing forms, which consists of producing homogeneous materials from elementary powders. This process is of paramount importance as it has the ability to reduce the particle size of the powders and can often promote bonding between elements which have low interaction and wet
Mat. Res.. Publicado em: 14/10/2019
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7. Investigation on Electrical Properties and Microdefects of Nb5+-Doped BaTiO3 Based Ceramics by Positron Annihilation Techniques
The influence of the Nb5+-doped content and the doping CaCO3 on the electrical properties and the microdefects of BSTN ceramics by Positron Annihilation Techniques were studied, which were fired at 1350 ºC for 2 hours in air. The PTCR characteristics in the BSTN samples were also investigated. Moreover, the information on microdefects in BSTN ceramics was d
Mat. Res.. Publicado em: 23/09/2019
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8. Ballistic Behavior of New Alumina Composites Reinforced with Niobo-Phosphate Glass
This work aimed to produce and evaluate the ballistic behavior of niobo-phosphate glass-doped alumina composites. The niobo-phosphate glass (30% Nb2O5- 30% P2O5- 20% CaO - 20% CaF2, by mol) were added to the alumina in six different weight percentages. The composite with the highest densification, measured by the Archimedes assay, was used for the ballistic
Mat. Res.. Publicado em: 23/09/2019
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9. Simple Niobium Catalysts Applied in Reflux and Ultrasound-Assisted Systems for Biofuel Synthesis
Using niobium compounds as heterogeneous catalysts in biodiesel production is a promising methodology from economic and environmental viewpoints. However, the application of niobium catalysts still is a challenge due to the high temperatures and pressures for moderate biofuel yields. Therefore, easily handled and applied materials have been developed to opti
J. Braz. Chem. Soc.. Publicado em: 16/09/2019
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10. Characterization of Ti-35Nb alloy surface modified by controlled chemical oxidation for surgical implant applications
ABSTRACT Titanium-Niobium alloys have been studied for biomedical applications due to their satisfactory biocompatibility. In order to improve the long-term implantation, surface modification techniques have been developed to generate suitable topography, roughness, chemical composition, surface energy, etc. Considering this approach, the present work aimed
Matéria (Rio J.). Publicado em: 16/09/2019
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11. Influence of Sintering Time on the PTCR Effect of Nb2O5-doped BaTiO3 Ceramics
The effects of the sintering time on the electrical properties and the positive temperature coefficient of resistance (PTCR) effect of Ba1.006(Ti1-xNbx)O3 (BTN) ceramics were investigated, which were sintered at 1190 ºC for 0.5-6 hours in a reducing atmosphere and then re-oxidized at 800 ºC for 1 hour. The results indicated that the sintering time affected
Mat. Res.. Publicado em: 16/09/2019
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12. Study of the Nb2O5 Insertion in ZnO to Dye-sensitized Solar Cells
Dye-sensitized solar cells (DSSC) have received much attention as an alternative to silicon-based solar cells, due to various advantages. Zinc oxide (ZnO) is an n-type semiconductor employed as photoanode on DSSC. The decrease of charge recombination is an efficient strategy capable of improving the photovoltaic performance of the device. In this perspective
Mat. Res.. Publicado em: 01/07/2019