Synthesis and optical property of MgMoO4 crystals

In this work, we report on the synthesis of MgMoO4 crystals by oxide mixed method. The powder was calcined at 1100 degrees C for 4h and analyzed by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Field emission gun scanning electron microscopy (FEG-SEM), Ultraviolet-visible (UV-vis) absorption spectroscopy and Photoluminescence (PL) measurement. XRD analyses revealed that the MgMoO4 powders crystallize in a monoclinic structure and are free secondary phases. UV-vis technique was employed to determine the optical band gap of this material. MgMoO4 crystals exhibit an intense PL emission at room temperature with maximum peak at 579 nm (yellow region) when excited by 350 nm wavelength at room temperature.

Mechanochemical synthesis of CaTiO3 from CaCO3 - TiO2 mixture

The synthesis of calcium titanate, CaTiO3, was performed by mechanical activation and thermal treatment. Milling for up to 360 minutes in a planetary ball mill mechanically activated an equimolar mixture of CaCO 3 and TiO2 powders. A small amount of mechanically activated mixtures was pressed into briquettes and calcined at 850°C for two hours. The effect of mechanical activation on the solid-state reaction was studied using X-ray powder diffraction and differential thermal analysis. The change of morphology and size of powder particles due to milling, were determined by SEM, while BET analysis was used to determine the specific surface area of the powder. The sintering process was followed by a dilatometer during thermal treatment up to 1300°C. The main conclusion of the analysis of conducted investigations is that CaTiO3 ceramics can be obtained from an activated mixture at a much lower temperature than reported in the literature owing to acceleration of the chemical reaction and sintering.

Materiais derivados de hidróxidos duplos lamelares: síntese, caracterização e aplicação em adsorção e processos avançados de oxidação

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

Effect of silica surface on luminescence properties of tb3+-glutamic acid.

We studied the effect of silica surface on luminescence properties of terbium complex by spectroscopy characterization, where microparticles of mesoporous silica type MSU-X was prepared. We used silica with different surface: calcined, washed, functionalized with 3- aminopropyl-triethoxysilane (APTES), and 3-glycidoxypropyl-trimethoxysilane (GPTMS); impregnated with Tb3+-glutamic acid complex. The obtained materials were characterized by scanning electron microscopy, porosity measurements, small-angle X-ray scattering, as structural characterization; Fourier transform infrared and luminescence spectroscopy, as spectroscopy characterization. Finally, we observed that functional groups at the silica surface lead to changes on luminescent properties of the final materials. The observed shift of the absorption and emission bands can be assigned to the effect of the functional groups of mesoporous silica.

Análise da resposta dielétrica e varistora de compostos cerâmicos multifásicos à base de Ca2CU2Ti4-xSnxO12 (0,0 < x< 4,0)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Caracterização da distribuição física dos dolomitos do membro Búzios no Campo de Badejo - Bacia de Campos

In the region of Badejo oil Ffeld (Campos Basin) lies an Lower Albian dolomitic layer that shows reservoir rock and seal conditions, among others and, it is occasionally karstified. This work applies geostatistical techniques of ordinary and indicatior kriging, in an attempt to determine a method that assists the analysis of different scenarios offered for petroleum drilling from a quantitative point of view this fact is justified, because there are different visions and strategies that would be adopted under different dolomite conditions (stable - low porosity and high density; reservoir - high porosity and medium density; instable - high porosity and low dentisty). The main objective is a methodological introduction that has not been tested in dolomites before aiming to characterize the distribution of the three conditions described above by ordinary and indicatior kriging, which was based on the obtained data from the dolomite layer identification through well logs interpretation and correlation, followed by seismic interpretation. In addition, it was generated structural contour maps, based on 2D and 3D seismic data interpretation, and then, seismic attributes maps were calculated, in order to transform them into pseudo-density maps, i.e., maps that correlate the density values with the attribute values. As primary results, structural contour maps and seismic attributes were obtained and ordinary and indicatior kriging maps were done, on which it is possible to interpret the distribution of the main reservoir and risk probability for drilling of exploration wells obtaining trends N35E and N10W direction for areas of stability or reservoir levels, while the central part of the map presents a higher risk for loss of drilling fluid. The cut-off values levels were based on the values of first and third quartiles of cumulative histogram (instable and stable zones, respectively), as well as the reservoir level was set as the interval...

Produção de biodiesel etílico utilizando óxidos mistos derivados de hidróxidos duplos lamelares como catalisadores

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Óxidos derivados de hidromagnesitas e hidrotalcitas modificadas como catalisadores heterogêneos na síntese de biodiesel etílico

Pós-graduação em Química - IBILCE

Petrografia e geoquímica das rochas metacarbonatíticas do Complexo Angico dos Dias, divisa Bahia/Piauí, Brasil

Pós-graduação em Geociências e Meio Ambiente - IGCE