Investigação das propriedades ópticas, elétricas e estruturais em ametista

Pós-graduação em Ciência e Tecnologia de Materiais - FC

Desenvolvimento de uma câmara fototérmica com transdutor transparente para monitoramento de água em etanol combustível

Pós-graduação em Engenharia Elétrica - FEIS

Novas técnicas de detecção de fase óptica em interferômetros homódinos aplicadas à caracterização de atuadores piezoelétricos flextensionais

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Síntese e caractrização de nanopartículas magnéticas do tipo caroço@casca de 'CO'@'PD' com propriedades para aplicações tecnológicas

Pós-graduação em Química - IQ

Influência dos dopantes potássio e lítio na cerâmica relaxora niobato de chumbo e magnésio (PMN)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeito de diferentes tempos de condicionamento e condições de envelhecimento na resistência à flexão de cerâmicas ácido sensíveis

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeito da neutralização e remoção sônica do precipitado do ácido fluorídrico na resistência à fratura de coroas cerâmicas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Luminescência e propriedades estruturais de 'LI''TA'O IND.3'nanoestruturado dopado com európio (III) e magnésio

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Preparação e caracterização eletroquímica de material catódico do tipo La2/3-xLi3xTiO3 para aplicações em baterias de Lítio

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Theoretical investigation of geometric configurations and vibrational spectra in citric acid complexes

The performance of advanced electronic ceramics is directly related to the synthesis route employed. Sol-gel methods are widely used for this purpose. However, the physicochemical intermediate steps are still not well understood. Better understanding and control of these processes can improve the final quality of samples. In this work, we studied theoretically the formation of metal complexes between citric acid and lithium or barium metal cations with different citric acid/metal proportions, using Density Functional Theory electronic structure calculations. Infrared and Raman scattering spectra were simulated for the more stable geometric configurations. Using this methodology, we identified some features of complexes formed in the synthesis process. Our results show that the complexes can be distinguished by changes in the bands assigned to C=O, COH-, and COO- group vibrations. An estimate of the most stable complexes is made based on total energy.

Contact parameters in two dimensions for general three-body systems

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Propiedades Eléctricas en Membranas de Complejos Electrolitos Poliméricos PVA-OH/LI2SO4/PEG400

Lithium ion conducting polymer electrolytes based on polyvinyl Alcohol (PVA-OH) complexed with salt Li2SO4 and different weight percent ratios of PEG(400) plasticizer have been prepared by solution cast technique using deionized water as solvent. The thermogravimetric analysis (TGA) showed that the thermal stability of the materials depended on the plasticizer content. The FTIR study confirmed the polymer salt complex formation. The modulus spectra indicated the non-Debye nature of the material; a dominant relaxation process is visible being associated with the dynamic glass transition, relaxation-a. The maximum of each peak is shifted to higher frequencies as the plasticizer increases due to an enhancement of dipolar mobility in the origin of cooperative motions. A power law frequency dependence of the real part of the electrical conductivity is observed, which is characteristic of the effects of ion-ion and/or ion-chain correlations in ion motion. This variation is well fitted to a Jonscher's expression.

Estudo dos efeitos do LiNO3 na reação Álcali-Sílica e comparação com os efeitos da cinza volante na reação

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Análise da superfície de cerâmicas de dissilicato de lítio após imersão em soluções ácidas e a base de flúor

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Survival rate, load to fracture, and finite element analysis of incisors and canines restored with ceramic veneers having varied preparation design

Purpose: To evaluate the survival rate, success rate, load to fracture, and finite element analysis (FEA) of maxillary central incisors and canines restored using ceramic veneers and varying preparation designs.Methods and Materials: Thirty human maxillary central incisors and 30 canines were allocated to the following four groups (n=15) based on the preparation design and type of tooth: Gr1 = central incisor with a conservative preparation; Gr2 = central incisor with a conventional preparation with palatal chamfer; Gr3 = canine with a conservative preparation; Gr4 = canine with a conventional preparation with palatal chamfer. Ceramic veneers (lithium disilicate) were fabricated and adhesively cemented (Variolink Veneer). The specimens were subjected to 4 x 106 mechanical cycles and evaluated at every 500,000 cycles to detect failures. Specimens that survived were subjected to a load to fracture test. Bidimensional models were modeled (Rhinoceros 4.0) and evaluated (MSC.Patrans 2005r2 and MSC.Marc 2005r2) on the basis of their maximum principal stress (MPS) values. Survival rate values were analyzed using the Kaplan-Meier test (alpha = 0.05) and load to fracture values were analyzed using the Student t-test (alpha = 0.05).Results: All groups showed 100% survival rates. The Student t-test did not show any difference between the groups for load to fracture. FEA showed higher MPS values in the specimens restored using veneers with conventional preparation design with palatal chamfer.Conclusion: Preparation design did not affect the fracture load of canines and central incisors, but the veneers with conventional preparation design with palatal chamfer exhibited a tendency to generate higher MPS values.