Composto De Sìlica-titania-grafite (sio2/tio2/grafite) Como Material Cerâmico Eletricamente Condutor E Processo Sol-gel De Obtenção Do Mesmo

Novo processo de obtenção de Sílica-titânia-grafite (SiO2/TiO2/Grafite) como um novo material cerâmico eletricamente condutor, para ser utilizado na construção e elaboração de componentes eletroquímicos, sensores, componentes microeletrônicos entre outros.BR0303303 (A)C04B35/00C04B35/14C04B35/00C04B35/14BR20030303303C04B35/00C04B35/14C04B35/00C04B35/1

Oxido misto SiO2/Sb2O3 : estudo da tecnica de preparação, caracteristicas, propriedades e aplicações do material obtido

Orientador: Yoshitaka GushikemTese (doutorado) - Universidade Estadual de Campinas, Instituto de QuimicaDoutorad

Estudos das atividades eletrocataliticas das ftalocianinas de Co (II) e Fe (II) tetrassulfonadas suportadas sobre silica gel quimicamente modificada com ion piridinio

Orientador: Yoshitaka GushikemDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de QuimicaMestrad

Electrochemical study of oxidation process of amitriptiline using sensor based on carbon paste containing immobilized DNA on inorganic matrix

In the present work the voltammetric behavior and the electroxidation process of amitriptiline (AMT) in electrochemical sensor based on carbon paste containing DNA immobilized on the inorganic matrix prepared by sol-gel process (SiO2/Al2O3/Nb2O5). The method of Laviron verified that the electroxidation process of AMT is irreversible and high speed of electron transfer. The study of the oxidation of AMT and influence of pH showed slope of 0.059 V/pH (similar the nernstian system: 0.0592 V/pH) suggesting that it involves the transfer of one proton and one electron

Incorporação de cinzas de borracha como substituto parcial de agregados finos em concreto

The construction industry is responsible for a high consumption of natural resources, demanding high quantities of aggregate materials for use in construction. In addition, large quantities of rubber waste generated worldwide have emphasized the need to find practical reuse applications. The present study partially replaces fine aggregates by ash from a co-processing of milled and burned conveyor belt rubber waste. Test specimens with ash concentrations of 0%, 5%, 10%, 15% and 20%, were made comparing its workability, mechanical axial resistance and absorption of water by capillarity. It was concluded that the partial replacement of sand by 5% of rubber ash has improved the traditional concrete mixture, with better workability, less amount of water, leading to a greater resistance to axial compressive and acceptable absorption of water. Thus, the results confirm that the concrete with incorporation of rubber ash is a potential alternative technology to achieve sustainable development in the construction industry.A indústria da construção civil é responsável por um grande consumo de recursos naturais, exigindo quantidades expressivas de materiais agregados para uso na construção. Além disso, resíduos de borracha são gerados enormes quantidades em todo o mundo, enfatizando a necessidade de encontrar aplicações práticas para sua reutilização. O presente estudo substitui parcialmente agregados finos por cinzas de um co-processamento de resíduos de borracha de correias transportadoras moídas e queimadas. Amostras preparadas com concentrações de cinzas de 0%, 5%, 10%, 15% e 20%, foram utilizadas para testes de comparação de trabalhabilidade, resistência axial mecânica e absorção de água por capilaridade. Concluiu-se que a substituição parcial da areia por 5% das cinzas de borracha melhorou a mistura de concreto tradicional, com melhor trabalhabilidade, menor quantidade de água necessária, levando a uma maior resistência à compressão axial e à absorção aceitável de água. Assim, os resultados confirmam que o concreto com incorporação de cinzas de borracha é uma tecnologia alternativa potencial para alcançar o desenvolvimento sustentável na indústria da construção

Development and application of graphite-SiO2/Al2O3/Nb2O5-methylene blue (GRP-SiAlNb-MB) composite for electrochemical determination of dopamine

In the present paper an amperometric sensor based on graphite-SiO2/Al2O3/Nb2O5-methylene blue (GRP-SiAlNb-MB) composite has been successfully prepared for dopamine (DA) determination in real samples. The electrochemical behavior of DA at the GRP-SiAlNb-MB has been evaluated by employing cyclic voltammetry. The best ratio (m/m) of GRP-SiAlNb-MB composite was found to be 1:0.54. Under optimized conditions (pH 7.5 in 0.15 mol L−1 phosphate buffer) the amperometry method responds linearly to DA from 5.0 up to 500.0 μmol L−1 (r = 0.995) with limits of detection and quantification of 1.49 and 4.97 μmol L−1, respectively. The developed method was successfully applied for DA determination in real samples of pharmaceutical formulations and can be used for routine quality control analysis of pharmaceutical formulations containing DA. The use of inorganic matrix SiAlNb was found to be very useful to adsorb MB in the composite material with further improvement of the anodic peak current of DA

Study of the characteristics and properties of the SiO2/TiO2/Nb2O5 material obtained by the sol–gel process

Abstract The SiO2/TiO2/Nb2O5 material was set by the sol–gel method and was characterized by several techniques through thermogravimetric, spectroscopic, and textural analyzes. For the two synthesized materials, the specific surface area was 350.0 and 494.0 m2 g−1 (SiTiNb-A and SiTiNb-B, respectively). An enhance of the crystalline order with the temperature increase of the thermal treatment was observed. Through X-ray Photoelectron Spectroscopy analysis, the binding energy values for the Ti 2p and Nb 3d levels showed the insertion of Ti and Nb atoms in the silica matrix. The Electron Dispersive Spectroscopy analyses also confirmed the high dispersion of the metals presented on the materials surface. The Thermogravimetric Analysis showed weight loss for the of 37.6% (SiTiNb-A) and 29.7% (SiTiNb-B). The presence of the crystalline phases TiO2-anatase and monoclinic-Nb2O5 in the materials was confirmed through the data obtained by association of powder X-ray Diffraction and FT-Raman. Values obtained from optical band-gap aimed the dependence of the oxides concentration and the calcination temperature. Finally, the pyridine adsorption studies have indicated the presence of Lewis and Brønsted acid sites