1000 resultados para Compósitos poliméricos. Fibras de casca de piaçava. Fogão solar
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Recent research seeking to elucidate the possible effects of different types of physical training on the morphological adaptations of skeletal muscle. Although it is relatively easy to study the effects of exercise training in humans, such research becomes limited due to the invasive nature of the biopsies and the risk inherent in the use of human subjects. Thus, the application of animal models of training has been considered an appropriate strategy for the study of muscular adaptations in response to exercise. Objective: This study used a rodent model to determine the possible effects of aerobic and strength training on the CSA of fibers of the plantaris muscle. Methods: 24 male Wistar rats (80 to 120 days, 250 to 400 g) were randomly divided into 3 groups: aerobic training (TA, n = 8), strength training (ST, n = 8) and control (CO, n = 8). The animals in groups TA and TF were subjected to 8 weeks of training, while the animals of group C remained without any stimulus from start to finish the training period. At the end of the experiment, the animals were sacrificed and right plantar muscles dissected and removed. For morphological and morphometric analysis of muscle fibers was performed staining was performed H.E. Results: There was no significant difference in initial body weight between experimental groups. After 8 weeks of training, the TA group showed a significant reduction in final body weight, compared to CO and TF groups. With respect to the CSA of fibers of the plantaris muscle, no significant difference between the groups CO and TA. On the other hand, the strength training promoted a significant increase in AST of the group TF in compared with the groups CO and TA. Conclusion: Strength training used in this study promoted an increase in CSA of fibers of the plantaris muscle. On the other hand, animals submitted to aerobic training showed no changes in the CSA of the fibers, however, there was reduction in PC animals. The data strongly suggest the use of animal model of strength training used in this study as an appropriate strategy for studying the hypertrophic response of skeletal muscle.
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This paper had the objective of determining the transition regions between the juvenile and mature wood of Corymbia citriodora (Eucalyptus citriodora) of 29 years of age from the Experimental Station of Forest Science (EECFA-LCF/ESALQ-USP), located in Anhembi, in the State of São Paulo. The regions of juvenile and mature wood were characterized through anatomical studies - axial fiber length - following the recommendations of the International Association of Wood Anatomists (1989) using disks at the DBH of the trees. The measurements of fiber length were made in equipment for acquisition, diagnosis and image analysis. Five slices were made for every centimeter, in the radial direction and six fiber lengths per slice were measured, producing 30 measurements per sample region. In the total, 1740 lengths of fiber were measured in three disks that were studied. Results indicate a trend of accentuated and linear increase for the length of fibers, from the pith to 11 cm of radial of about 79%. Between 12 cm and 19 cm of the radius, fibers length remained almost constant, and from that point on, the fiber length tended to slightly increase to the bark. It can be concluded that for these trees, at this height of sampling, when the tree has 29 years of age, the extension of the juvenile wood goes up to 52% of its radius.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Pós-graduação em Química - IQ
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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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...
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The benzoxaxine resin is a new class of thermoset phenolic resin, which is presenting, in the lasts decades, a great application in the aircraft industry due mainly to its excellent mechanical and thermal properties. This resin associates the mechanical properties of epoxy resin with the thermal and flame retardant properties of phenolic resin. In this context, they are considered polymers of high performance and they are excellent candidates to replace the current thermoset matrices used in the processing of high performance composites. Thus, in this study nanostructured composites Benzoxazine/CNT were produced at different concentrations of functionalized and non-functionalized CNT (0,1%; 0,5% and 1,0% w/w). The thermal stability of the benzoxazine resin and its nanostructured composites was studied using thermogravimetry (TGA) and degradation kinetic model Ozawa-Wall-Flynn (O-W-F). The thermal characterization also included differential scanning calorimetry (DSC) and dynamic-mechanical analysis, infrared spectroscopy with Fourier transform (FTIR) and scanning electron microscopy (SEM).The introduction of non-functionalized CNT at low concentrations resulted in nanostructured composites with better thermal properties in relation to the neat resin. For all cases, however, the dispersion of CNT in the matrix was ineffective
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)