Controle preditivo bilinear aplicado a um motor de indução

The present work is based on the applied bilinear predictive control applied to an induction motor. As in particular case of the technique based on predictive control in nonlinem systems, these have desperted great interest, a time that present the advantage of being simpler than the non linear in general and most representative one than the linear one. One of the methods, adopted here, uses the linear model "quasi linear for step of time" based in Generalized Predictive Control. The modeling of the induction motor is made by the Vectorial control with orientation given for the indirect rotor. The system is formed by an induction motor of 3 cv with rotor in squirregate, set in motion for a group of benches of tests developed for this work, presented resulted for a variation of +5% in the value of set-point and for a variation of +10% and -10% in the value of the applied nominal load to the motor. The results prove a good efficiency of the predictive bilinear controllers, then compared with the linear cases

Protótipo de uma unidade com tri-geração de energia para utilizações remotas: aplicação de módulo secondutivo gerador termoelétrico

The generation for termoeletricity is characterized as a solid process of conversion of thermal energy (heat) in electric without the necessity of mobile parts. Although the conversion process is of low efficiency the system presents high degree of trustworthiness and low requisite of maintenance and durability. Its principle is based on the studies of termogeneration carried through by Thomas Seebeck in 1800. The frank development of the technologies of solid state for termoeletricity generation, the necessity of the best exploitation of the energy, also with incentive the cogeneration processes, the reduction of the ambient impact allies to the development of modules semiconductors of high efficiency, converge to the use of the thermoeletric generation through components of solid state in remote applications. The work presents the development, construction and performance evaluation of an prototype, in pilot scale, for energy tri-generation aiming at application in remote areas. The unit is composed of a gas lamp as primary source of energy, a module commercial semiconductor for thermoelectric generation and a shirt for production of the luminosity. The project of the device made compatible a headstock for adaptation in the gas lamp, a hot source for adaptation of the module, an exchanger of to be used heat as cold source and to compose first stage of cogeneration, an exchanger of tubular heat to compose second stage of cogeneration, the elaboration of a converter dc-dc type push pull, adequacy of a system of acquisition of temperature. It was become fullfilled assembly of the prototype in group of benches for tests and assay in the full load condition in order to evaluate its efficiency, had been carried through energy balance of the unit. The prototype presented an electric efficiency of 0,73%, thermal of 56,55%, illumination of 1,35% and global of 58,62%. The developed prototype, as the adopted methodology of assay had also taken care of to the considered objectives, making possible the attainment of conclusive results concerning to the experiment. Optimization in the system of setting of the semicondutor module, improvement in the thermal insulation and design of the prototype and system of protection to the user are suggestions to become it a commercial product

Análise teórico-experimental do coeficiente de perfomance (COP) de um sistema de refrigeração por jato-compressão

The use of waste heat of energy conversion equipment to produce a cooling effect, consists currently in a very interesting way of efficiency improvement of energy systems. The present research has as intention the theoretical and experimental study of a new intermittent refrigeration system ejector cycle characteristics, with use of waste heat. Initially, was doing a bibliographical survey about the vapor ejector refrigeration system technology. In the following stage was doing a simulation of the corresponding thermodynamic cycle, with preliminarily intention to evaluate the performance of the system for different refrigerants fluids. On the basis of the results of the simulation were selected the refrigerant fluid and developed an experimental group of benches of the refrigeration system considered, where pressure and temperature sensory had been inserted in strategical points of the refrigeration archetype and connected to a computerized data acquisition system for measure the refrigerant fluid properties in the thermodynamic cycle. The test results obtained show good agreement with the literature

No cotidiano da escola: o pensar e agir de jovens e adultos

The necessity of the view of the Youth and Adults Education (EJA) subjects beyond of their academic failures becomes imperative for a reconfiguration of this teaching modality. Thus, the compromise of this study is to go into these subjects‘ universe, give them a voice and, therefore, understand, in general, the web of relationships between these subjects and the school. It is understood that it is not possible to figure out the means attributed by the subjects without consideration, as an essential element, the social context in which such means has been built. For the development of this study, the methodology adopted was the ethnographic research. The procedures used for the data construction were the participative observation, the semi-structured interviews with a focal group, and the individualized semi-structured interviews. For the understanding of the data constructed in the field, the content analysis technique was used, which reach the expectations of an interpretative analysis. The observation occurred mainly in the classrooms, on a public school, located in a City of Natal/RN. The interviews were taken with a sample of eight students, males and females, with 25 to 60 year-olds. Such interviews highlight that for the young adult students, the school is much more than a place to learn. They realize such space as enabler of social interaction, as well as the possibility of rising through new professional horizons and, therefore achieve a social mobility. For the older students, mainly among women, the return to the school benches brings into the learning discourse, the desire of making new friends, having moments of meeting, chatting and relaxation, finally, to forget the problems of the day by day. The school quotidian observation allows a better understanding of the action of the subjects in relationship with the school practices. Finally, it can be affirmed that seeking for the school has not only the intention to recover the time lost in the childhood. Learning remains as a secondary goal. It does not matter whether they will be retained or promoted to the next level at the end of the academic year, what really matters is to be in school.