ORCID Profile
0000-0002-9280-4334
Current Organisation
Universidade Estadual Paulista Júlio de Mesquita Filho - Câmpus de Bauru
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Publisher: Trans Tech Publications, Ltd.
Date: 02-2003
Publisher: Elsevier BV
Date: 09-2009
Publisher: Springer Science and Business Media LLC
Date: 17-05-2012
Publisher: Trans Tech Publications, Ltd.
Date: 07-2014
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.975.207
Abstract: Metal oxide nanocomposites were prepared by two different routes: polyol and sol-gel. Characterization by X ray diffraction showed that the first process produces directly a two-phase material, while the sol-gel powder never showed second phase below 600°C. Light spectroscopy of the treated powders indicated similarities for the processed materials. Although the overall material compositions are about the same, different structural characteristics are found for each processing. With the exception of Ti-Zn materials, all the double metal oxide powders showed higher absorbance than either TiO 2 powder .
Publisher: FapUNIFESP (SciELO)
Date: 2021
DOI: 10.1590/S1517-707620210004.1395
Abstract: RESUMO Esse trabalho mostra uma rota sintética mediada por tetraetilenoglicol (P. E. 325°C) em que utiliza o ácido túngstico, como material de partida. A formação de uma suspensão estável de cor azul foi observada durante o curso da reação. O tamanho das partículas depende do tempo de síntese, sendo que partículas de tamanho em torno de 400 nm foram obtidas após 15 minutos de reação em tetraetilenoglicol. Os materiais particulados foram então recozidos em diferentes temperaturas: 150°, 350°C, 500°C e 800°C, e caracterizados por TGA / DSC, DRX, FT-RAMAN, MEV, Espectroscopia óptica UV-VIS e adsorção de N2 a 77K. Observou-se que a síntese proporcionou WO3 sob fase ortorrômbica que evoluiu para monoclínica após tratamento térmico na temperatura igual ou superior a 350°C. A caracterização morfológica indicou a formação de partículas ovoides quando tratadas em temperaturas em torno de 500°C, temperatura a partir da qual a área superficial diminui drasticamente. A atividade fotocatalítica para a degradação de rodamina B (rhB, 10 mg.L-1) foi avaliada sob irradiação ultravioleta (6 Watts). Maior atividade foi encontrada para o material tratado a 500°C, sendo que descoramento foi total após 180 minutos na presença de 10 mg desse catalisador.
Publisher: Elsevier BV
Date: 12-2014
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 06-2007
Publisher: Trans Tech Publications, Ltd.
Date: 07-2014
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.975.106
Abstract: The addition of two compounds, calcium silicate and calcium zirconate was tested, in the preparation of Bi: 2212 silver sheathed wires by powder-in-tube method, which were successfully tested previously in processing chips. The wires were treated in an atmosphere of O 2 /Ar using partial melting method. The characterizations were structural and on their electrical and magnetic properties. As the results, transition temperatures were higher than the expected for this stage, ranged from 105K (BSCCO880) to 116K (+Si883). The critical current densities encountered in transport and magnetization measurements were improved in comparison with the wires without addition.
Publisher: Trans Tech Publications, Ltd.
Date: 11-2005
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.498-499.388
Abstract: The Bi-Sr-Ca-Cu-O system has been one of the most studied superconducting ceramic materials for industry applications. The most of the studies with this aim are on silver/ceramic composites, due to the benefits and great compatibility of this metal with the oxide. In this paper we describe a systematic and comparative study on Ag/BSCCO composite, made by the citrate route, in which the ceramic pellets are sintered in the presence of silver powder using several proportions and having several granulations. It was observed that the introduction of fine (0.5 and 2 μm) silver powder in the proportions of 5 wt. % always implies in a better critical current density compared to the no silver pellet. According to the results, the silver powder in excess of 5 wt.% may not promote best electrical properties, depending on the size of the silver particles.
Publisher: Trans Tech Publications, Ltd.
Date: 07-2014
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.975.233
Abstract: Nanostructured composites based on titanium dioxide have been studied in order to improve optical and photo-catalytic properties, as well as their performance in gas sensors. In this work, titanium and tin dioxides were simultaneously synthesized by the polyol method resulting in TiO 2 platelet coated with SnO 2 nanoparticles as was observed by scanning electron microscopy. The thermal analysis showed that the combined synthesis promotes more easily the crystallization of the TiO 2 rutile phase. The composite obtained after heat treatment at 500 °C showed to be formed of almost only rutile phases of both oxides. The optical properties analyzed by UV-Vis spectroscopy showed that the combined oxides have higher absorbance, which reinforces a model found in the literature based on the flow of photo-generated electrons to the conduction band of SnO 2 delaying the recombination of charges.
Publisher: Elsevier BV
Date: 08-2004
Publisher: Elsevier BV
Date: 09-2007
Publisher: Elsevier BV
Date: 04-2011
Publisher: IOP Publishing
Date: 14-03-2006
Publisher: Springer Science and Business Media LLC
Date: 03-06-2012
Publisher: Springer Science and Business Media LLC
Date: 09-12-2012
Publisher: Elsevier BV
Date: 08-2004
Publisher: IOP Publishing
Date: 03-07-2006
Publisher: Wiley
Date: 28-04-2008
Abstract: Tin glycolate particles were prepared by a simple, one-step, polyol-mediated synthesis in air in which tin oxalate precursor was added to ethylene glycol and heated at reflux. Hexagonal-shaped, micron-sized tin glycolate particles were formed when the solution had cooled. A series of tin oxides was produced by calcination of the synthesized tin glycolate at 600-800 degrees C. It was revealed that the micron-sized, hexagonal-shaped tin glycolate now consisted of nanosized tin-based particles (80-120 nm), encapsulated within a tin glycolate shell. XRD, TGA, and FT-IR measurements were conducted to account for the three-dimensional growth of the tin glycolate particles. When applied as an anode material for Li-ion batteries, the synthesized tin glycolate particles showed good electrochemical reactivity in Li-ion insertion/deinsertion, retaining a specific capacity of 416 mAh g(-1) beyond 50 cycles. This performance was significantly better than those of all the other tin oxides nanoparticles (<160 mAh g(-1)) obtained after heat treatment in air. We strongly believe that the buffering of the volume expansion by the glycolate upon Li-Sn alloying is the main factor for the improved cycling of the electrode.
Publisher: Elsevier BV
Date: 08-2005
Publisher: Elsevier BV
Date: 09-2007
Publisher: Trans Tech Publications, Ltd.
Date: 08-2012
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.727-728.888
Abstract: Among the researches on preparation and test of nanostructured materials, titanium dioxide and zinc oxide have been the most frequent studied oxides. In order to extend their properties, composites have been prepared using three different methods: Polyol Method, Sol-gel Process and a combination of the two processes (hybrid process). Recent research showed best properties in composite materials than in pure oxides. In this work is presented the preparation and the structural characterization of ZnO-TiO 2 composite nanostructures to be tested for their performance in electrocatalysis and in further trial on photovoltaic cells.
Publisher: Elsevier BV
Date: 05-2007
Publisher: FapUNIFESP (SciELO)
Date: 2020
DOI: 10.1590/S1517-707620200003.1135
Abstract: RESUMO Filmes constituídos por amido de mandioca, álcool polivinílico (PVA) e argila Bentonita (BNT) e glicerol como plastificante foram obtidos utilizando o método casting. A fim de aumentar a compatibilidade dos polímeros ao mineral e sua hidrofobicidade, estes foram posteriormente modificados quimicamente utilizando metacrilato de glicidila (GMA) para a substituição dos grupamentos hidroxilas por vinílicos. Este procedimento gerou filmes com excelente estabilidade a sorção de água e permeabilidade ao vapor de água 15% menor quando comparados coms os filmes sem modificação química. Adicionalmente, esta estratégia também resultou na melhora de 25% na resistência a tração, mantendo o mesmo módulo de Young mas, com uma leve diminuição na estabilidade térmica (início de degradação 14ºC menor). A adição da argila BNT gera filmes compósitos com propriedades, mecânicas, térmicas e físicas diferenciadas, contudo há uma dependência entre a quantidade de reforço e a distribuição estrutural das lamelas de argila na matriz. As modificações químicas foram comprovadas por RMN H1, FTIR, DRX e os filmes foram caracterizados por DRX, sorção e permeabilidade a água, ensaios mecânicos (tração, alongamento e módulo de Young) e TGA. A utilização de 1% m/m deste reforço gera compósitos com BNT estruturalmente esfoliado, independentemente da prévia modificação com metacrilato de glicidila. Já a formulação com 5% m/m gerou filmes compósitos intercalados. Qualquer outro teor de reforço exibe estruturas lamelares aglomeradas (empacotadas). Destaca-se que nas formulações reforçadas com 1% de argila, houve melhora em cerca 30% na resistência a tração com permeabilidade a água 60% menor, para cargas maiores de argila. Estes fatos apontam que as modificações propostas neste trabalho geraram propriedades promissoras para a produção de materiais de embalagem biodegradáveis.
Location: Brazil
Location: Australia
Location: Brazil
Start Date: 1997
End Date: 2000
Funder: Fundação de Amparo à Pesquisa do Estado de São Paulo
View Funded ActivityStart Date: 1997
End Date: 2003
Funder: São Paulo Research Foundation
View Funded ActivityStart Date: 1991
End Date: 1996
Funder: Conselho Nacional de Desenvolvimento Científico e Tecnológico
View Funded ActivityStart Date: 2010
End Date: 2012
Funder: Fundação de Amparo à Pesquisa do Estado de São Paulo
View Funded ActivityStart Date: 2007
End Date: 2007
Funder: Fundação de Amparo à Pesquisa do Estado de São Paulo
View Funded ActivityStart Date: 2006
End Date: 2006
Funder: Fundação de Amparo à Pesquisa do Estado de São Paulo
View Funded ActivityStart Date: 1991
End Date: 1994
Funder: Conselho Nacional de Desenvolvimento Científico e Tecnológico
View Funded Activity