Desenvolvimento da célula base de microestruturas periódicas de compósitos sob otimização topológica

This thesis develops a new technique for composite microstructures projects by the Topology Optimization process, in order to maximize rigidity, making use of Deformation Energy Method and using a refining scheme h-adaptative to obtain a better defining the topological contours of the microstructure. This is done by distributing materials optimally in a region of pre-established project named as Cell Base. In this paper, the Finite Element Method is used to describe the field and for government equation solution. The mesh is refined iteratively refining so that the Finite Element Mesh is made on all the elements which represent solid materials, and all empty elements containing at least one node in a solid material region. The Finite Element Method chosen for the model is the linear triangular three nodes. As for the resolution of the nonlinear programming problem with constraints we were used Augmented Lagrangian method, and a minimization algorithm based on the direction of the Quasi-Newton type and Armijo-Wolfe conditions assisting in the lowering process. The Cell Base that represents the composite is found from the equivalence between a fictional material and a preescribe material, distributed optimally in the project area. The use of the strain energy method is justified for providing a lower computational cost due to a simpler formulation than traditional homogenization method. The results are presented prescription with change, in displacement with change, in volume restriction and from various initial values of relative densities.

Corpos Queer e a experiência da sexualidade: notas para o conhecimento da educação física

This study had the goal of make a dialogue between queer theory and the thoughts of the French philosopher Maurice Merleau-Ponty in the categories of body and sexuality. From this dialogue, other goals were designed, namely: identify possible recurrences of the experience of bodies and queer sexualities, designed under Merleau-Ponty’s perspective, to the knowledge of Physical Education and reflect on this domain of knowledge using the notions of queer epistemology and esthesia. The study had as methodology the phenomenological attitude proposed by Merleau-Ponty and use the reduction as technic of research. Trying linking these thoughts we used the cinema of the Spanish director Pedro Almodóvar as perceptive strategy, an exercise of look as possibility of reading the world and new ways of perceiving the human being. We appreciate three films, namely: All About My Mother (1999), The Skin I Live In (2011) and Bad Education (2004), which put us in touch with bodies and queer sexualities, with the body of esthesia, of the ecstasy, sensations and lived experiences, un type of art whose contours are not fixed or determinable, postulate by Merleau-Ponty. The philosopher, provide a rich conceptual view of the body and their sexual experience, extends and opens horizons of thought and reflection about queer experience, one experience indeterminate and contingent as a singular way of inhabiting the world. Those horizons opened by the philosopher and added to the queer perspective contribute to put in question the modes of knowledge production and the knowledge about body and sexuality in Physical Education. Finally, we point that this theoretical conversation give us clues to reflect about the reverberations of a queer epistemology for Physical Education usiging one type of knowledge guided by esthesia and sensitivity as marks of another scientific rationality.

Desenvolvimento e caracterização de um compósito matriz metálica (CMM): aço EUROFER97 reforçado com Carbeto de Tântalo - TaC

Steel is an alloy EUROFER promising for use in nuclear reactors, or in applications where the material is subjected to temperatures up to 550 ° C due to their lower creep resistance under. One way to increase this property, so that the steel work at higher temperatures it is necessary to prevent sliding of its grain boundaries. Factors that influence this slip contours are the morphology of the grains, the angle and speed of the grain boundaries. This speed can be decreased in the presence of a dispersed phase in the material, provided it is fine and homogeneously distributed. In this context, this paper presents the development of a new material metal matrix composite (MMC) which has as starting materials as stainless steel EUROFER 97, and two different kinds of tantalum carbide - TaC, one with average crystallite sizes 13.78 nm synthesized in UFRN and another with 40.66 nm supplied by Aldrich. In order to improve the mechanical properties of metal matrix was added by powder metallurgy, nano-sized particles of the two types of TaC. This paper discusses the effect of dispersion of carbides in the microstructure of sintered parts. Pure steel powders with the addition of 3% TaC UFRN and 3% TaC commercial respectively, were ground in grinding times following: a) 5 hours in the planetary mill for all post b) 8 hours of grinding in the mill Planetary only for steel TaC powders of commercial and c) 24 hours in the conventional ball mill mixing the pure steel milled for 5 hours in the planetary mill with 3% TaC commercial. Each of the resulting particulate samples were cold compacted under a uniaxial pressure of 600MPa, on a cylindrical matrix of 5 mm diameter. Subsequently, the compressed were sintered in a vacuum furnace at temperatures of 1150 to 1250 ° C with an increment of 20 ° C and 10 ° C per minute and maintained at these isotherms for 30, 60 and 120 minutes and cooled to room temperature. The distribution, size and dispersion of steel and composite particles were determined by x-ray diffraction, scanning electron microscopy followed by chemical analysis (EDS). The structures of the sintered bodies were observed by optical microscopy and scanning electron accompanied by EDS beyond the x-ray diffraction. Initial studies sintering the obtained steel EUROFER 97 a positive reply in relation to improvement of the mechanical properties independent of the processing, because it is obtained with sintered microhardness values close to and even greater than 100% of the value obtained for the HV 333.2 pure steel as received in the form of a bar