411 resultados para actuation


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This thesis introduces and analyzes a dielectric elastomer actuator (DEA) working in zipping mode. Electrostatic zipping is a very familiar actuation principle used in silicon micro-electro-mechanical systems. With lower voltage supply, electrostatic zipping can provide great performance for forces and displacements of an elastic membrane. Applying this principle to dielectric elastomers, the softness of the material will provide better compliance compared to silicon materials. After the presentation of an analytical model, this thesis investigates how system geometry and elastomer pre-tensioning affect system response. Results highlight how a proper selection of system parameters makes it possible to improve system regulation and reduce operating voltage requirements. Potential applications of zipping DEAs are for microfluidic control and electro-forming.

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Esta pesquisa abrange mulheres atuantes no chamado protestantismo histórico, principalmente vinculadas à Igreja Metodista do Brasil. O trabalho pretende visibilizar especialmente mulheres leigas e suas redes, geralmente informais, de articulação e chamar a atenção para seu papel na constituição destas comunidades de fé. Trata-se de um aspecto pouco explorado nas investigações sobre o protestantismo no Brasil que, quando abordado, se restringe a alguns ícones femininos. O foco principal do trabalho se restringe ao período de 1930, ano em que a Igreja Metodista do Brasil se constituiu como instituição autônoma, desvinculando-se formalmente de sua congênere nos EUA, até 1970/71, quando mulheres metodistas passam a ser admitidas no presbiterato, ou seja, podem solicitar a ordenação ao pastorado. Além de discutir a produção bibliográfica principalmente no âmbito da história do protestantismo, a pesquisa se baseia em fontes primárias, como boletins e jornais denominacionais, relatórios de eventos, correspondências e informações dispersas em diferentes materiais. Como referencial teórico a pesquisa se valeu da micro-história, procurando assim dar vida a personagens esquecidos e desvelar enredos ocultados pela história oficial. Portanto, além de demonstrar aspectos da atuação de mulheres no protestantismo brasileiro, silenciados tanto na memória institucional como na historiografia em suas diferentes matizes, a pesquisa pretende contribuir para uma avaliação crítica da mentalidade de mulheres sobre sua atuação no campo religioso, entre a adequação aos padrões culturais dominantes e os indícios de autonomia de pensamento diante de demandas específicas.(AU)

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Este estudo teve por objetivo investigar quais as representações sociais que os tutores têm, sobre a própria atuação na educação a distância, em cursos de Licenciatura. Com o propósito de analisar se o tutor se reconhece como docente e participante no processo de formação do aluno o estudo de campo teve como sujeitos tutores com formação acadêmica em licenciaturas e que atuam em cursos do mesmo nível nessa modalidade, em instituição particular de Ensino Superior da Grande São Paulo. Os caminhos percorridos para tal investigação justificam-se na trajetória formativa pessoal e nos espaços da experiência que se constroem no cotidiano dessa atividade. Um estudo sobre os modelos disponíveis na modalidade a distância no ensino superior do país, um breve histórico sobre os aspectos da EAD no Brasil e uma explanação sobre o modelo no qual esses tutores atuam, além de uma aproximação com as representações sociais da profissão docente, são abordagens presentes neste trabalho, que pretendeu contribuir para a educação aprofundando conhecimentos sobre o tutor responsável pelo acompanhamento dos alunos nos ambientes virtuais de aprendizagem, considerando as possibilidades de ampliação, de alcance e democratização da educação no país. Os Resultados demonstram que há uma tendência de ser considerada, pelo tutor, uma atuação que se confunde com a essência da profissionalidade docente, numa indicação de que é necessária uma reflexão mais aprofundada sobre a função e a atuação desses profissionais.(AU)

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Este trabalho tem como objetivo fazer um levantamento das intervenções que são realizadas pelos psicólogos que atuam nas Unidades Básicas de Saúde (UBS) do Grande ABC, bem como traçar um perfil destes profissionais. Pretendeu-se fazer na Região do Grande ABC este levantamento, baseando-se na tradição que a Psicologia tem de pesquisar-se como profissão, nos últimos trinta anos. A análise dos dados da pesquisa se deu através de quatro categorias levantadas a partir das mudanças que o exercício da profissão nas UBS requer: 1) do âmbito do atendimento, do individual para o coletivo; 2) do atendimento em consultório para instituição pública; 3) do enfoque do trabalho, do curativo para o preventivo; 4) da área de atuação, da saúde mental para a psicologia da saúde. Os resultados apresentados são oriundos de trinta e oito entrevistas realizadas com psicólogos das UBS s da Região do Grande ABC, no decorrer do ano de 2002, que trazem as dificuldades para o desenvolvimento das atividades. Dentre elas, destaca-se as de ordem política, econômica e social, que independem do desejo dos profissionais. Além destas, constatou-se dificuldades frente à formação profissional e à compreensão do papel e da função do psicólogo nas UBS s.

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Este trabalho tem como objetivo fazer um levantamento das intervenções que são realizadas pelos psicólogos que atuam nas Unidades Básicas de Saúde (UBS) do Grande ABC, bem como traçar um perfil destes profissionais. Pretendeu-se fazer na Região do Grande ABC este levantamento, baseando-se na tradição que a Psicologia tem de pesquisar-se como profissão, nos últimos trinta anos. A análise dos dados da pesquisa se deu através de quatro categorias levantadas a partir das mudanças que o exercício da profissão nas UBS requer: 1) do âmbito do atendimento, do individual para o coletivo; 2) do atendimento em consultório para instituição pública; 3) do enfoque do trabalho, do curativo para o preventivo; 4) da área de atuação, da saúde mental para a psicologia da saúde. Os resultados apresentados são oriundos de trinta e oito entrevistas realizadas com psicólogos das UBS s da Região do Grande ABC, no decorrer do ano de 2002, que trazem as dificuldades para o desenvolvimento das atividades. Dentre elas, destaca-se as de ordem política, econômica e social, que independem do desejo dos profissionais. Além destas, constatou-se dificuldades frente à formação profissional e à compreensão do papel e da função do psicólogo nas UBS s.

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Block copolymers are versatile designer macromolecules where a “bottom-up” approach can be used to create tailored materials with unique properties. These simple building blocks allow us to create actuators that convert energy from a variety of sources (such as chemical, electrical and heat) into mechanical energy. In this review we will discuss the advantages and potential pitfalls of using block copolymers to create actuators, putting emphasis on the ways in which these materials can be synthesised and processed. Particular attention will be given to the theoretical background of microphase separation and how the phase diagram can be used during the design process of actuators. Different types of actuation will be discussed throughout.

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The thesis describes an investigation into methods for the design of flexible high-speed product processing machinery, consisting of independent electromechanically actuated machine functions which operate under software coordination and control. An analysis is made of the elements of traditionally designed cam-actuated, mechanically coupled machinery, so that the operational functions and principal performance limitations of the separate machine elements may be identified. These are then used to define the requirements for independent actuators machinery, with a discussion of how this type of design approach is more suited to modern manufacturing trends. A distributed machine controller topology is developed which is a hybrid of hierarchical and pipeline control. An analysis is made, with the aid of dynamic simulation modelling, which confirms the suitability of the controller for flexible machinery control. The simulations include complex models of multiple independent actuators systems, which enable product flow and failure analyses to be performed. An analysis is made of high performance brushless d.c. servomotors and their suitability for actuating machine motions is assessed. Procedures are developed for the selection of brushless servomotors for intermittent machine motions. An experimental rig is described which has enabled the actuation and control methods developed to be implemented. With reference to this, an evaluation is made of the suitability of the machine design method and a discussion is given of the developments which are necessary for operational independent actuators machinery to be attained.

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A status report of the modelling and simulation work that is being undertaken as part of the TIMES (Totally Integrated More Electric Systems) project is presented. Dynamic power quality simulations have been used to asses the performance of the electrical system of a EMA based actuation system for an Airbus A330 size aircraft, for both low voltage 115 V, and high voltage 230 V three-phase AC systems. The high voltage system is shown to have benefits in terms of power quality and reduced size and weight of equipment.

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To examine the detailed operation of the power distribution network in a future more electric aircraft that employs electric actuation systems, a Micro-Cap SPICE simulation is developed for one of the essential buses. Particular attention is paid to model accurately the most important effects that influence system power quality. Representative system and flight data are used to illustrate the operation of the simulation and to assess the power quality conditions within the network as the flight control surfaces are deployed. The results illustrate the importance of correct cable sizing to ensure stable operation of actuators during transient conditions.

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The objective of this research was to find Young's elastic modulus for thin gold films at room and cryogenic temperatures based on the flexional model which has not been previously attempted. Electrical Sonnet simulations and numerical methods using Abacus for the mechanical responses were employed for this purpose. A RF MEM shunt switch was designed and a fabrication process developed in house. The switch is composed of a superconducting YBa2 Cu3O7 coplanar waveguide structure with an Au bridge membrane suspended above an area of the center conductor covered with BaTiO3 dielectric. The Au membrane is actuated by the electrostatic attractive force acting between the transmission line and the membrane when voltage is applied. The value of the actuation force will greatly depend on the switch pull-down voltage and on the geometry and mechanical properties of the bridge material. Results show that the elastic modulus for Au thin film can be 484 times higher at cryogenic temperature than it is at room temperature. ^

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Microstructure manipulation is a fundamental process to the study of biology and medicine, as well as to advance micro- and nano-system applications. Manipulation of microstructures has been achieved through various microgripper devices developed recently, which lead to advances in micromachine assembly, and single cell manipulation, among others. Only two kinds of integrated feedback have been demonstrated so far, force sensing and optical binary feedback. As a result, the physical, mechanical, optical, and chemical information about the microstructure under study must be extracted from macroscopic instrumentation, such as confocal fluorescence microscopy and Raman spectroscopy. In this research work, novel Micro-Opto-Electro-Mechanical-System (MOEMS) microgrippers are presented. These devices utilize flexible optical waveguides as gripping arms, which provide the physical means for grasping a microobject, while simultaneously enabling light to be delivered and collected. This unique capability allows extensive optical characterization of the structure being held such as transmission, reflection, or fluorescence. The microgrippers require external actuation which was accomplished by two methods: initially with a micrometer screw, and later with a piezoelectric actuator. Thanks to a novel actuation mechanism, the "fishbone", the gripping facets remain parallel within 1 degree. The design, simulation, fabrication, and characterization are systematically presented. The devices mechanical operation was verified by means of 3D finite element analysis simulations. Also, the optical performance and losses were simulated by the 3D-to-2D effective index (finite difference time domain FDTD) method as well as 3D Beam Propagation Method (3D-BPM). The microgrippers were designed to manipulate structures from submicron dimensions up to approximately 100 μm. The devices were implemented in SU-8 due to its suitable optical and mechanical properties. This work demonstrates two practical applications: the manipulation of single SKOV-3 human ovarian carcinoma cells, and the detection and identification of microparts tagged with a fluorescent "barcode" implemented with quantum dots. The novel devices presented open up new possibilities in the field of micromanipulation at the microscale, scalable to the nano-domain.

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With the advantages and popularity of Permanent Magnet (PM) motors due to their high power density, there is an increasing incentive to use them in variety of applications including electric actuation. These applications have strict noise emission standards. The generation of audible noise and associated vibration modes are characteristics of all electric motors, it is especially problematic in low speed sensorless control rotary actuation applications using high frequency voltage injection technique. This dissertation is aimed at solving the problem of optimizing the sensorless control algorithm for low noise and vibration while achieving at least 12 bit absolute accuracy for speed and position control. The low speed sensorless algorithm is simulated using an improved Phase Variable Model, developed and implemented in a hardware-in-the-loop prototyping environment. Two experimental testbeds were developed and built to test and verify the algorithm in real time.^ A neural network based modeling approach was used to predict the audible noise due to the high frequency injected carrier signal. This model was created based on noise measurements in an especially built chamber. The developed noise model is then integrated into the high frequency based sensorless control scheme so that appropriate tradeoffs and mitigation techniques can be devised. This will improve the position estimation and control performance while keeping the noise below a certain level. Genetic algorithms were used for including the noise optimization parameters into the developed control algorithm.^ A novel wavelet based filtering approach was proposed in this dissertation for the sensorless control algorithm at low speed. This novel filter was capable of extracting the position information at low values of injection voltage where conventional filters fail. This filtering approach can be used in practice to reduce the injected voltage in sensorless control algorithm resulting in significant reduction of noise and vibration.^ Online optimization of sensorless position estimation algorithm was performed to reduce vibration and to improve the position estimation performance. The results obtained are important and represent original contributions that can be helpful in choosing optimal parameters for sensorless control algorithm in many practical applications.^

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The objective of this research was to find Young's elastic modulus for thin gold films at room and cryogenic temperatures based on the flexional model which has not been previously attempted. Electrical Sonnet simulations and numerical methods using Abacus for the mechanical responses were employed for this purpose. A RF MEM shunt switch was designed and a fabrication process developed in house. The switch is composed of a superconducting YBa2Cu3O7 coplanar waveguide structure with an Au bridge membrane suspended above an area of the center conductor covered with BaTiO3 dielectric. The Au membrane is actuated by the electrostatic attractive force acting between the transmission line and the membrane when voltage is applied. The value of the actuation force will greatly depend on the switch pull-down voltage and on the geometry and mechanical properties of the bridge material. Results show that the elastic modulus for Au thin film can be 484 times higher at cryogenic temperature than it is at room temperature.

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This re search analyzes the talks dynamics about policy established in YouTube symbolic space. We are interested in examining the way in which the commentators of the video " Globo e os Protestos " articulated in the field intended for comments, a public space directed to the dissemination and circulation of meanings about policy issues. The video studied was published by PC Siqueira and Diego Quint eiro , during the June 2013 protests in Br azil, to direct the political understanding of the movement lived in that period. According to them, the protests had left political position and therefore the protesters should reject the coverage by TV Globo (a comunication vehicle with ideals of right) and allow the participation of political parties linked to the ideological left spectrum. This narrative generated empathy and controversy betwe en commentators, which produced in the comments, an intense argumentative process about these theses (right and left). To understand the phenomenon, we conducted an exploratory qualitative research, the main methodological procedure was a ethnomethodological discourse analysis. We seek the observation of the ways in which the commentators es tablished talks about politics in the comments space, for, thereafter , organize categories of analysis based on identified discursive recurrences. The empirical reflections are supported from discussions about the YouTube potential, while digital media com prising massive strategies and while articulating space in the engagement of individuals in political issues; also confront the aspects involved in the conversation practices that results in sociability dynamics and , especially , in conflict, on the socio - t echnical networks; and finally, we propose a reflection about the circuit actuation in which the people take ownership and realize new readings about the products received. Concluding that the use of digital media , such as YouTube, has caused significant c hanges in the forms of production and reception of symbolic products and ways in which people participate in political issues concerning life in society.

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The health paradigm, consolidated in the last century, directed the training of health professionals, educated under the aegis of the Flexnerian training, fragmentary and hospital-centered model. However, it proved to be insufficient to meet the demands of the Unified Health System and the population. In this sense, the National Curriculum Guidelines for Undergraduate health courses emerge as a normative framework in proposing a new professional profile, as well as the recommendation of strategies for the restructuring of curricula and teaching practices, and one of them is the teaching-service integration. Therefore, the aim of this study was to investigate the process of training of Physiotherapy course students of the Federal University of Paraíba with the guiding principle of teaching-service integration, considering DCN. In this sense, the chosen method was a case study with qualitative approach. The sample was intentional, including all faculty members of the permanent staff of the Department of Physiotherapy at UFPB, linked to curriculum components whose practice scenarios occur in the SUS network and time longer than one year in that component. The data collection technique was the semi-structured interview. Data analysis was performed using the content analysis technique. The following categories were considered: professional training for SUS, integration of students to the SUS network services, the relationship between theory and practice in the training of physiotherapists, teaching and health professional partnership in the teaching-learning process and programs of training reorientation and their integration with the course. The results allowed identifying positive points in the teaching-service integration: recognition of the importance of integration activities between university and health services based on the insertion of students in the network, the combined actuation with health service professionals and the opportunity to work in a multidisciplinary team; the existence of structured and organized School Network; participation of students and teachers in government programs that offer the experience of insertion in the labor market. The following weaknesses stood out: difficulties in agreement, planning and evaluation of activities by the service; gap between theoretical and practical activities; lack of definition of roles of teacher and health service professionals in the training process and the fragile relationship of reorientation of vocational training programs with the curricular activities of the course. The teaching-service integration as a guiding principle in the analysis of the formation of physiotherapists reveals limits and possibilities for training that meets the health needs of the population. Thus, the choices of educational institutions regarding the care model have an influence on health practices, as well as the commitment by management and services and the permeability to social control instances decisively contribute to the improvement in the training of future professionals. Thus, the commitment of all involved for the effective change in the training process of health paradigm is indispensable.