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Movimento estudantil e repressão política: o Ato Público na Pontifícia Universidade Católica de São Paulo (1977) e o destino de uma geração de estudantes
(Universidade Federal de São Carlos, 2008-11-26) Cancian, Renato; Villa, Marco Antonio; https://lattes.cnpq.br/0666499374255763
This study examines the university student movement of the 1970s and the Public Act at the Pontifical Catholic University of São Paulo (PUC-SP) in 1977, culminating in an episode of police violence against the students. The focus of the search fell on the path of life of a group of former student activists in order to understand, first, how they are linked and part of the student movement, and secondly, if the experience of participation in student movement was able to generate some influence or socialization in terms of political and professional after entering the stage of university education of ex-militants. Theoretically, this study establishes a dialogue with the sociological approaches that focus on the radical student collective actions and roles of young people, and is back to understanding the changes in the patterns of militancy that might occur in the transition from juvenile to life adulthood and integration into the world of work. The methodology of the History of Life provided the basis for the analysis of the biography of former student activists, and from that methodological feature found that the political militancy was a determining factor of student activism and, consequently, a more active participation in the movement university student. The study showed that after training and shutdown of the student movement, the former student activists have continued the practice of political militancy and experience of participation in the student movement has strong influence in their career options.
Modelagem, simulação e otimização de transformadores piezoelétricos de modo radial para aplicações em conversão de potência
(Universidade Federal de São Carlos, 2008-11-26) Barros, Marcelo Henrique Martins de; Moreira, Fernando Manuel Araújo; https://lattes.cnpq.br/1809254923092721; https://lattes.cnpq.br/8514491119497005
This work seeks to improve the modeling, analysis and the optimization of the parameters of piezoelectric transformer (PT) built with polarized Pb(Zr,Ti)O3 electro-ceramics for applications in power conversion, as well as to characterize them. The main motivation resides in the great similarity of the electric model of the PT in relation to the LC resonant tanks plus magnetic transformer commonly employees in AC/DC and DC/DC power converters. Such similarity could make possible its application in power conversion, with good energy efficiency, as well as reduction of volume, weight, complexity, cost and electromagnetic emission, when compared to the converters based on magnetic devices, that today dominate almost all the applications. The power conversion accomplished in way more and more rational and with low losses of energy it is, without a doubt, one of the great concern of our time, for the expressive economic and environment impacts. A PT is a electric device that combines an piezoelectric driver on the primary side with a piezoelectric receiver on the secondary side. Both can work with transverse or longitudinal vibration modes. These drivers and receivers are made of piezoelectric elements, being for its time composed of metal plates (electrodes) and of polarized electro-ceramics. To the likeness of the magnetic transformers, piezoelectric transformers are transmission devices of electric energy, even so accomplished through eletro-mechanic coupling between the driver and the receiver. They can be used in the function of insulators, reducers or elevators of the applied voltage on the primary side. Based on the piezoelectric and wave equations, the electric equivalent circuit of a piezoelectric transformer in radial-mode vibration was obtained and later on improved, starting from a more complete approach, including effects that are usually despised. A performance analysis was accomplished through computer simulation and it was explored the limits for the power rate transfer for thermal and electromechanics considerations. Later on an outline of optimization of the piezoelectric transformer in a radial-mode was traced, in order to maximize the efficiency and of adapting it to applications of power conversion; also through computer simulation. Since the electric equivalent circuit of a piezoelectric transformer is commonly identical to the LC resonant tanks used in power conversion in high frequency switch-mode resonant scheme, the PT can substitute the magnetic transformer, the indutor and the capacitor of the resonant tanks, as well as to increase the energy efficiency and to reduce significantly the number of devices, the volume, the cost and the electromagnetic emission of an application in power conversion.