Desenvolvimento de células solares de perovskita baseadas em filmes de óxidos nanoestruturados

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

Projeto estrutural de galpão metálico segundo recomendações da NBR8800

This work deals in a general way, the history and advantages of steel buildings, as well as its increasing usage in Brazil in the last century. This work also generally describes some types and its uses of metal frame. It also demonstrates the use of the NBR 8800: 2008 standard and its calculation methods through the scale out materials regulated in Brazil for an industrial warehouse project small and simple portico metal frame. Given that the construction requirements include a locational influence following the normative indications of the NBR 6123, for the winding scale out, since this effect combined with the permanent loads must be seriously evaluated due to the shape type effort about acting simultaneous axial force and bending moments obeying the limitations applied to the structure according to NBR 8800. As it has been explained the calculations that ensures mechanical stability and suggesting an analysis of the efficiency of the used materials

Modificação da superfície de óxidos de ferro por dextrana derivatizada para aplicações em liberação de fármaco

Pós-graduação em Química - IQ

Nanopartículas de Pd suportadas em compósitos óxido-carbono: influência das interações metal-suporte na oxidação de etanol em meio básico

Fuel cells powered directly with ethanol (Direct Ethanol Fuel Cell-DEFC) are very attractive for the possibility of using a renewable fuel in the generation of clean energy. However, it is still necessary to deepen the understanding of catalytic processes and their dependence on the catalytic properties. This work proposes to study the catalytic activity of ethanol oxidation in an alkaline medium of Pd nanoparticles supported in carbon oxide hybrids using various transition metal oxides (MoO3, TiO2, WO3 and ZrO2). The materials prepared were characterized by techniques such as X-ray diffraction, transmission electron microscopy (TEM) and X-ray dispersive spectroscopy (EDX) to verify the structure, the distribution of particles in the supports and the presence of Pd on particles oxide. Experiments of X-rays absorption spectroscopy were carried out using soft X-rays (SXS) to evaluate the changes in the electronic properties of the Pd particles caused by interactions with different oxides. Measurements of cyclic voltammetry and potential sweeps of adsorbed CO oxidation allowed evaluating general aspects of the catalysts' electrochemical behavior and determining the electrochemically active area thereof. The catalytic performances of ethanol oxidation in alkaline medium were evaluated by electrochemical techniques (potential scan and chronoamperometry), and showed an improvement in activity with the addition of oxides in material containing only carbon, which was most pronounced for the catalyst containing TiO2. This improvement was predominantly associated with the electronic effects caused by the interaction of Pd on the support, causing a vacancy in the 4d band of Pd which, in turn, produces variations in adsorption energies of the species...

Efeito da adição de flúor e cálcio no gel clareador a base de peróxido de hidrogênio na penetração, cor e microdureza

The objective of this study was to evaluate the effect of adding calcium ions and fluoride in the formulation of a whitening gel 35% hydrogen peroxide in its penetration through the dental structure, whitening efficacy and surface hardness of dental enamel. 80 teeth bovine incisors were used, which were obtained enamel and dentin disks of the buccal surface with 6mm diameter and 2mm thick (1 mm of enamel and dentin 1mm). The samples were divided into four groups stratified according to the protective substance / remineralizing added to the gel of hydrogen peroxide 35%: Group Ca - Calcium gluconate 0.5%; Group F - Sodium fluoride 0.2%; Group Ca + F - Calcium gluconate 0.5% and Sodium Fluoride 0.2%; Control group - no substance was added. The initial color of the samples and the hardness of the enamel were measured before the bleaching procedures. The specimens from each group were placed on a metallic support on which there was a simulated pulp chamber, which was filled with acetate buffer to collect and stabilize the penetrated peroxide. The respective bleaching treatments were applied 3 times, total of 30 minutes of application. The amount of peroxide which passed through the samples was determined by absorbance spectrophotometry. The hardness of the samples was measured immediately after bleaching. Next, the samples were immersed in artificial saliva for 7 days, after which the final color was evaluated. Data were statistically analyzed adopting a 5% significance level

Desenvolvimento de sensores de gás a partir de óxido semicondutor nanoestruturado

The present work aims to study one-dimensional nanomaterials semiconductors grown via by phase systems Grande oxides Technological Interest for applications in gas sensors. The Used material was tin oxide (SnO2) for their functional properties, and the grow method was the Polymeric Precursors. The films grown were the nanomaterials about substrates of alumina, deposited via spin coating technique, followed by heat treatment at 300C for 1 hour and 650C for 2 hours. Later the films of Performance sensors (sensitivity, speed response, selectivity, and stability) will be in avaliated in a hermetic chamber with controlled atmosphere and temperature. The synthesized materials were its structural and morphological properties characterized in atomic force microscopy (AFM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (not have this result with Me). We sought to investigate one influence of different conditions for obtaining films (Variation Layers number) in structural and microstructural properties of semiconductors oxides. The synthesis method proved very effective, generating films with micro definitely, uniformity of the nanoparticles and hum high level of porosity, what makes the material of a viable final paragraph applicability

Estudo e desenvolvimento de filmes espessos de CeO2 obtidos por tape casting

Tape Casting proved to be an effective method for the production of thick films of CeO2 pure and doped with La. For this study, the nanoparticles used to form the slurry were synthesizes by the H-M method, at 100°C for 8 minutes, using KOH mineralizer. The slurry was made in aqueous solvent, requiring optimal control of surroundings conditions so that the produced tape has conditions to be studied. However, there's no toxicity or flammability in the film made by such solvent, being pleasing to the environment. The structural, optical and electrical properties of the films obtained by the Tape Casting process were studied by the methods of X-ray diffraction, scanning electron microscopy, specific surface area, Ultraviolet-visible spectroscopy and voltage-current measures, varying the electric field and frequency. From the results obtained by laboratory experiments, based on the literature, it was possible to reveal and understand some CeO2 features pure and doped with La