993 resultados para Gerador de indução auto-excitado
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Empregou-se a associação midazolam e detomidina para indução de anestesia com cetamina em 16 potros, machos e fêmeas, entre três e seis meses de idade, distribuídos aleatória e equitativamente em dois grupos (GI e GII). A todos os animais foram administrados midazolam, via intramuscular, na dose de 0,2mg/kg, e após 15 minutos, detomidina, via intravenosa, na dose de 0,02mg/kg. Os animais do GII receberam cetamina pela via intravenosa, dose 2,0mg/kg, três minutos após a administração de detomidina. Quinze minutos após o midazolam, ocorreram sedação e ligeira ataxia, e dois minutos após a administração da detomidina, decúbito lateral em todos os potros, com miorrelaxamento e presença dos reflexos de deglutição e miorrelaxamento, anal e oculo-palpebral. A associação midazolam/detomidina e cetamina provocou ausência dos reflexos de deglutição. Para todos os animais, o tempo de recuperação foi de 45-60 minutos, e temperatura retal e frequência respiratória permaneceram estáveis. Ocorreram bradicardia, bloqueio atrioventricular de segundo grau e aumento das pressões arteriais sistólica, diastólica e média após dois minutos da administração da detomidina. A associação midazolam/detomidina e cetamina demonstrou ser um método eficiente e seguro para a anestesia de potros hígidos.
Indução da expressão precoce de sintomas de Guignardia citricarpa em frutos de laranjeira 'pêra-rio'
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O presente trabalho teve por objetivo avaliar a influência de diferentes concentrações de ethephon na expressão precoce de sintomas de Guignardia citricarpa em frutos de laranjeira 'Pêra-Rio'. Para tal, frutos assintomáticos e isentos de aplicações com fungicidas, com 20 e 28 semanas após a queda de pétalas, foram coletados em área de comprovada existência da doença, no município de Conchal-SP e levados ao Laboratório de Fitopatologia da FCAV/UNESP, em Jaboticabal-SP, onde foram tratados com soluções nas seguintes doses de ethephon: i) 1,57 g L-1; ii) 2,10 g L-1; iii) 2,42 g L-1; iv) Testemunha (água). Todas acrescidas de imazalil a 0,25 g L-1, para prevenir podridões de pós-colheita. Após os tratamentos, os frutos foram mantidos em câmara incubadora para B.O.D., calibrada à temperatura de 25ºC ±1ºC, por 15 dias. Posteriormente, os frutos foram submetidos a quatro avaliações, em intervalos semanais, sendo atribuídas notas que variaram de zero (ausência de sintomas) a 6 (sintomas severos). Os dados da severidade da doença observados nos frutos colhidos prematuramente e submetidos aos diferentes tratamentos com ethephon foram comparados aos observados em frutos ensacados e não ensacados, mantidos no campo até a maturação natural. Constatou-se maior equivalência de sintomas nos frutos com idade entre 20 e 28 semanas, quando estes foram tratados com 2,10 g L-1 de ethephon e avaliados entre 28 e 35 dias. Concluiu-se que o emprego de ethephon, nestas condições, viabilizou a expressão precoce dos sintomas da mancha preta em frutos contendo infecções quiescentes de G. citricarpa, com antecedência de, pelo menos, 105 dias antes da colheita. Tal resultado constitui-se, portanto, em alternativa de grande aplicabilidade na detecção precoce de sintomas de mancha preta.
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Cette étude analyse l'expérience de réorientation curriculaire atravers le sujet générateur, vécue dans les écoles qui composent le système municipal d'éducation de Belém du Pará - École Cabana, en ayant comme locus de recherche l'École Municipale João Carlos Batista. Ce mouvement de réorientation curriculaire, qui rompt avec le modèle traditionnel d'un curriculum linéaire, hiérarchique et fragmenté a comme préssuposées théoriquesméthodologiques les principes et les catégories freireanas la pédagogie critique qui estime un curriculum interdisciplinaire, dialogique, démocratique et contextuel, à partir de la systématisation d'une proposition theorico-méthodologique de réorientation curriculaire par le thème générateur, c'est-à-dire, en partant de situations-problème de la communauté scolaire, en faisant des relations négociées par les connaissances scolaires pour la compréhension et possible intervention dans la réalité. Cette proposition est mise en oeuvre non seulement à Belém, mais aussi par d autres municipalités du Brésil. Étant donné que l'École Cabana est une expérience inovatrice dans la tentative de viabiliser une Éducation vraiment démocratique, elle dialogue encore avec autres expériences d'écoles de même nature au Brésil, (comme l'École Plural-MG, l'École Citoyen - RS et l'École Candanga DF). Á partir des idées de Paulo Freire, J. Sacristán, M. Apple, C. Linhares, A. Coulon et autres j apporte des réflexions epistemologiques concernant le problème de la recherche qui consiste sur le registre et l'analyse de la tentative de construction sociale de la connaissance par le thème générateur qui a eu lieu à l'École Cabana dans la période de 2001 à 2004. Comme procédure méthodologique, j'ai développé une Recherche qualitative, de caractère collaboratif, en utilisant comme techniques de rassemble de données l observation participative dans le quotidien écolier, des interviews semi-structurées, et l'analyse des documents et des productions de l'École. Les résultats indiquent l'importance du registre de ce type d expérience, en soulignant leurs avances et reculs qui pourront servir de référentiel pour de futures politiques de réorientation curriculaire dans la direction de la construction sociale de la connaissance et, par conséquent, d'une Éducation plus démocratique et tournée vers une citoyenneté active
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The object of study of this thesis is the use of (self)training workshops as a fundamental process for the constitution of the teaching subject in mathematics education. The central purposes of the study were to describe and analyze a learning process of mathematics teachers supported by the training-research methodology, which procedures have been affected with the practice of (self)training workshops as a way of collaborating to the constitution of the teaching subject in Mathematics Education. The survey was conducted with a group of teachers in the city of Nova Cruz, Rio Grande do Norte through a process of continued education realized in the training workshops having as main goal the realization of the group s (self)training sessions in order to lead participants to the extent of their autonomy in their personal and professional transformations. The results obtained in the formative processes have shown the need to develop activities of mathematics teaching as a contribution to overcome the conceptual difficulties of the teachers, apart from their (self)reflections about themselves and the educational processes in which they belong. The results raised some propositions about (self)training workshops that may be incurred in practices to be included in the curriculum frameworks or materialize as a strategy of pedagogical work in training courses for teachers of mathematics. Also, they can constitute an administrative and educational activity to be instituted in the public schools of Basic Education
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
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Objetivou-se estudar os efeitos de ácido giberélico (GA3) (i.a.), nas concentrações de 50 e 100 mg L-1, acrescido do espalhante adesivo Extravon® a 0,05%, em duas aplicações via foliar e do paclobutrazol (PBZ) (i.a.), em doses de 2 e 4 g por planta, aplicado via solo, em uma única aplicação, na antecipação da floração do maracujazeiro-amarelo, em Araguari-MG. O delineamento experimental empregado foi em parcelas subdivididas, com cinco tratamentos (parcelas) e dois tratamentos (subparcelas), com quatro repetições e quatro plantas por parcela. Foram identificados 12 ramos terciários por parcela, com seis ramos expostos à luminosidade predominante pela manhã e seis com luminosidade predominante à tarde. Avaliaram-se os dois lados da espaldeira aos 103 dias após a primeira aplicação dos tratamentos, observando-se o comprimento dos ramos e de entrenós, número de nós e de botões florais. Os reguladores não promoveram respostas significativas para o comprimento dos entrenós e o número de botões florais. Porém, observaram-se indícios de maior número de botões florais com PBZ 2 g. O maior comprimento dos ramos foi obtido com GA3 100 mg L-1, sob luminosidade, pela manhã. Ao se compararem os tratamentos nas duas condições de luminosidade, o PBZ 4 g, independentemente da condição de luminosidade, proporcionou o menor comprimento dos ramos.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
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This work describes the study and the implementation of the vector speed control for a three-phase Bearingless induction machine with divided winding of 4 poles and 1,1 kW using the neural rotor flux estimation. The vector speed control operates together with the radial positioning controllers and with the winding currents controllers of the stator phases. For the radial positioning, the forces controlled by the internal machine magnetic fields are used. For the radial forces optimization , a special rotor winding with independent circuits which allows a low rotational torque influence was used. The neural flux estimation applied to the vector speed controls has the objective of compensating the parameter dependences of the conventional estimators in relation to the parameter machine s variations due to the temperature increases or due to the rotor magnetic saturation. The implemented control system allows a direct comparison between the respective responses of the speed and radial positioning controllers to the machine oriented by the neural rotor flux estimator in relation to the conventional flux estimator. All the system control is executed by a program developed in the ANSI C language. The DSP resources used by the system are: the Analog/Digital channels converters, the PWM outputs and the parallel and RS-232 serial interfaces, which are responsible, respectively, by the DSP programming and the data capture through the supervisory system
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We propose a multi-resolution approach for surface reconstruction from clouds of unorganized points representing an object surface in 3D space. The proposed method uses a set of mesh operators and simple rules for selective mesh refinement, with a strategy based on Kohonen s self-organizing map. Basically, a self-adaptive scheme is used for iteratively moving vertices of an initial simple mesh in the direction of the set of points, ideally the object boundary. Successive refinement and motion of vertices are applied leading to a more detailed surface, in a multi-resolution, iterative scheme. Reconstruction was experimented with several point sets, induding different shapes and sizes. Results show generated meshes very dose to object final shapes. We include measures of performance and discuss robustness.
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This work presents a set of intelligent algorithms with the purpose of correcting calibration errors in sensors and reducting the periodicity of their calibrations. Such algorithms were designed using Artificial Neural Networks due to its great capacity of learning, adaptation and function approximation. Two approaches willbe shown, the firstone uses Multilayer Perceptron Networks to approximate the many shapes of the calibration curve of a sensor which discalibrates in different time points. This approach requires the knowledge of the sensor s functioning time, but this information is not always available. To overcome this need, another approach using Recurrent Neural Networks was proposed. The Recurrent Neural Networks have a great capacity of learning the dynamics of a system to which it was trained, so they can learn the dynamics of a sensor s discalibration. Knowingthe sensor s functioning time or its discalibration dynamics, it is possible to determine how much a sensor is discalibrated and correct its measured value, providing then, a more exact measurement. The algorithms proposed in this work can be implemented in a Foundation Fieldbus industrial network environment, which has a good capacity of device programming through its function blocks, making it possible to have them applied to the measurement process
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This work describes the study and the implementation of the speed control for a three-phase induction motor of 1,1 kW and 4 poles using the neural rotor flux estimation. The vector speed control operates together with the winding currents controller of the stator phasis. The neural flux estimation applied to the vector speed controls has the objective of compensating the parameter dependences of the conventional estimators in relation to the parameter machine s variations due to the temperature increases or due to the rotor magnetic saturation. The implemented control system allows a direct comparison between the respective responses of the speed controls to the machine oriented by the neural rotor flux estimator in relation to the conventional flux estimator. All the system control is executed by a program developed in the ANSI C language. The main DSP recources used by the system are, respectively, the Analog/Digital channels converters, the PWM outputs and the parallel and RS-232 serial interfaces, which are responsible, respectively, by the DSP programming and the data capture through the supervisory system
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Ceramic substrates have been investigated by researchers around the world and has achieved a high interest in the scientific community, because they had high dielectric constants and excellent performance in the structures employed. Such ceramics result in miniaturized structures with dimensions well reduced and high radiation efficiency. In this work, we have used a new ceramic material called lead zinc titanate in the form of Zn0,8Pb0,2TiO3, capable of being used as a dielectric substrate in the construction of various structures of antennas. The method used in constructing the ceramic combustion synthesis was Self- Sustained High Temperature (SHS - "Self-Propagating High-Temperature Synthesis") which is defined as a process that uses highly exothermic reactions to produce various materials. Once initiated the reaction area in the reaction mixture, the heat generated is sufficient to become self-sustaining combustion in the form of a wave that propagates converting the reaction mixture into the product of interest. Were analyzed aspects of the formation of the composite Zn0,8Pb0,2TiO3 by SHS powders and characterized. The analysis consisted of determining the parameters of the reaction for the formation of the composite, as the ignition temperature and reaction mechanisms. The production of composite Zn0,8Pb0,2TiO3 by SHS performed in the laboratory, was the result of a total control of combustion temperature and after obtaining the powder began the development of ceramics. The product was obtained in the form of regular, alternating layers of porous ceramics and was obtained by uniaxial pressing. 10 The product was characterized by analysis of dilatometry, X-ray diffraction analysis and scanning electron microscopy. One of the contributions typically defined in this work is the development of a new dielectric material, nevertheless presented previously in the literature. Therefore, the structures of the antennas presented in this work consisted of new dielectric ceramics based Zn0,8Pb0,2TiO3 usually used as dielectric substrate. The materials produced were characterized in the microwave range. These are dielectrics with high relative permittivity and low loss tangent. The Ansoft HFSS, commercial program employee, using the finite element method, and was used for analysis of antennas studied in this work
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This work presents a model of bearingless induction machine with divided winding. The main goal is to obtain a machine model to use a simpler control system as used in conventional induction machine and to know its behavior. The same strategies used in conventional machines were used to reach the bearingless induction machine model, which has made possible an easier treatment of the involved parameters. The studied machine is adapted from the conventional induction machine, the stator windings were divided and all terminals had been available. This method does not need an auxiliary stator winding for the radial position control which results in a more compact machine. Another issue about this machine is the variation of inductances array also present in result of the rotor displacement. The changeable air-gap produces variation in magnetic flux and in inductances consequently. The conventional machine model can be used for the bearingless machine when the rotor is centered, but in rotor displacement condition this model is not applicable. The bearingless machine has two sets of motor-bearing, both sets with four poles. It was constructed in horizontal position and this increases difficulty in implementation. The used rotor has peculiar characteristics; it is projected according to the stator to yield the greatest torque and force possible. It is important to observe that the current unbalance generated by the position control does not modify the machine characteristics, this only occurs due the radial rotor displacement. The obtained results validate the work; the data reached by a supervisory system corresponds the foreseen results of simulation which verify the model veracity
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This dissertation dea1s with the active magnetic suspension controI system of an induction bearingIess motor configured with split windings. It analyses a dynamic modeI for the radial magnetic forces actuating on the rotor. From that, it proposes a new approach for the composition of the currents imposed to the machine's stator. It shows the tests accomplished with a prototype, proving the usefulness of the new actuating structure for the radial positioning controI. Finnaly, it points out the importance of adapting this structure to well-known rotational controI techniques, continuing this kind of equipment research, which is carried out at Federal University of Rio Grande do Norte since 2000
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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