164 resultados para Velocidade de vibração


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OBJECTIVE: To verify the use of maximal running distance performed on Hoff test to predict the anaerobic threshold speed (sAnT). METHODS: Ten young soccer players (age of 17 ± 1 years and body mass of 64.3 ± 2.1 kg) were subjects of the study. The subjects performed 12-min test, lactate minimum test to estimate the anaerobic threshold speed and a field test called Hoff. The purpose of Hoff test was to cover the maximum distance during a period of 10min moving a soccer ball through the track by dribbling. RESULTS: The distance covered during 12-min was 2673.2 ± 64.7 m, the sAnT was 11.6 ± 0.3 km.h-1 and distance covered during test Hoff test was 1458.7 ± 49.6 m. The distance covered during Hoff test was not significantly correlated with sAnT (r = -0.20; P > 0.05) and distance covered during 12-min test (r = -0.15; P > 0.05). The sAnT did not differ of speed correspondent 90% at 12-min speed and they were statistically correlated (r = 0.65). CONCLUSION: Thus, we concluded that maximal distance covered during Hoff test cannot provides a valid prediction of the anaerobic threshold speed.

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Pós-graduação em Engenharia Elétrica - FEIS

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Em geral, estruturas espaciais e manipuladores robóticos leves têm uma característica similar e inerente que é a flexibilidade. Esta característica torna a dinâmica do sistema muito mais complexa e com maiores dificuldades para a análise de estabilidade e controle. Então, braços robóticos bastantes leves, com velocidade elevada e potencia limitada devem considerar o controle de vibração causada pela flexibilidade. Por este motivo, uma estratégia de controle é desejada não somente para o controle do modo rígido mas também que seja capaz de controlar os modos de vibração do braço robótico flexível. Também, redes neurais artificiais (RNA) são identificadas como uma subespecialidade de inteligência artificial. Constituem atualmente uma teoria para o estudo de fenômenos complexos e representam uma nova ferramenta na tecnologia de processamento de informação, por possuírem características como processamento paralelo, capacidade de aprendizagem, mapeamento não-linear e capacidade de generalização. Assim, neste estudo utilizam-se RNA na identificação e controle do braço robótico com elos flexíveis. Esta tese apresenta a modelagem dinâmica de braços robóticos com elos flexíveis, 1D no plano horizontal e 2D no plano vertical com ação da gravidade, respectivamente. Modelos dinâmicos reduzidos são obtidos pelo formalismo de Newton-Euler, e utiliza-se o método dos elementos finitos (MEF) na discretização dos deslocamentos elásticos baseado na teoria elementar da viga. Além disso, duas estratégias de controle têm sido desenvolvidas com a finalidade de eliminar as vibrações devido à flexibilidade do braço robótico com elos flexíveis. Primeiro, utilizase um controlador neural feedforward (NFF) na obtenção da dinâmica inversa do braço robótico flexível e o calculo do torque da junta. E segundo, para obter precisão no posicionamento... (Resumo completo, clicar acesso eletrônico abaixo)

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In Brazil, the practice of Soccer is encouraged very early. It is common remark that parents enroll their sons into soccer schools, promoting the involvement of these children in formal practice. However, there are not many studies that assess the effects of this practice in the physical capacities of children. Thus, the question that guides this study is: children who practice soccer systematically present better development of physical, especially agility, coordination and speed? The objective of this study was to compare the performance in velocity tests, agility and coordination of boys of 10 and 11 years, category dentinho or Sub-11, practitioners of soccer in schools and non practicing. The study included male children, born in 1997 and 1998, formed two groups: group of practitioners of soccer and group of non practicing. To belong to the group of practitioners, the child was regularly engaged for at least 1 year, with 1 hour daily and 2 to 3 times per week. The participants of the group of non practicing were not involved in regular practice of soccer and were paired in weight and stature with participants of the group of practitioners of soccer. Each participant was individually assessed in neutral environment and without foreign interference. For the assessment of the agility, was utilized the (shuttle run) test. The race test 30 meters stopped was employed for the assessment of the speed. The test of fiddling between the cones was employed to measure the coordination. The time spent to perform 1 attempt to each test was used for the comparison between groups. These data were treated, initially, by descriptive statistics (mean and standard deviation) and, subsequently, were compared by means of Anova, for independent samples. The significance level was maintained at 5%. Through analysis of the results the conclusion is that the regular practice ...(Complete abstract click electronic access below)

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This work has as objective to show the vibrational analysis as a method of predictive maintenance as an auxiliar procedure in the fail detection in equipments, most specifically in the rotative ones, and with that help the maintenance team to have conditions to foresee the right time to do the swap of the components of the systems, what would lead to failures. Knowing the exact moment the resources of people and money can be focused in the critic operations to the plant. This technic has been already studied for more then 30 years and was widely used in this work, not only as an equipment condition verification method, but also, after the equipment replacement, was used to prove that the new fan was operating under the best work conditions and with that maintenance could return to contol the vibration level of the equipment, not being necessary any kind of intervention

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This work is initially based in give a solution to a problem consisting of lifting a load in a warehouse focusing specifically on the solution´s project and comparison of the results obtained following the sequence of the book and comparing these results with the finite elements simulation based on the 3D components modeling. Starting from that was realized the project of the worm gear reducer to solve the problem and makes the work easier. The project consisted basically of the study, project itself and simulation by software of a worm gear reducer and projects steps, starting with the initial problem conditions (to lifting a load up to an specific height at a given time) following all the reducer project sequence, starting by the preliminary draft and electric motor selection using iterative process, material selection, worm gear dimensioning, axles, keyways, bearings and coupling. After that was performed the three dimensional modeling of the components using SolidWorks software and simulating these components using Ansys software. The results show the importance of the CAD in terms of improving project development speed and reducing costs with prototypes

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This work aims to make the closed loop control of a three phase induction motor, through the integration of the following equipment: a frequency inverter, the actuator system; a programmable logic controller (PLC), the controller; an encoder, the velocity sensor, used as a feedback monitoring the control variable and the three-phase induction motor, the plant to be controlled. The control is performed using a Proportional - Integrative - Derivative (PID) approach. The PLC has a help instruction, which performs the auto adjustment of the controller, that instruction is used and confronted with other adjustment methods. There are several types of methods adjustments to the PID controllers, where the empirical methods are addressed in this work. The system is deployed at the Interface and Electro Electronic Control laboratory in the Universidade Estadual Paulista Júlio Mesquita Filho, Guaratinguetá, São Paulo, then, in the future, this work becomes an experiment to be conducted in the classroom, allowing undergraduate students to develop a greater affinity to the programs used by the PLC as well as studies of undergraduate and graduate works with the help of assembly made

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Existente desde os Jogos Olímpicos da Grécia Antiga, as corridas de velocidade ocupam espaço de destaque dentre as provas do atletismo. Em particular, os 100 metros rasos masculino é a prova cujas particularidades merecem ser investigadas, sobretudo em função das inúmeras alterações ocorridas ao longo dos anos. Por exemplo, a princípio, a corrida de velocidade era disputada nos Jogos Olímpicos da Grécia Antiga, com o nome de stádion ou dromo e com um percurso de 192,27 metros. Com a decadência e a extinção dos Jogos Olímpicos, a corrida de velocidade deixou de ser disputada, retornando em 1896, com o renascimento dos Jogos Olímpicos da Era Moderna. Entretanto, dentre as modificações nas provas do atletismo, as corridas de velocidade passaram a ser de 100 e 400 metros rasos, o bloco de partida passou a ser obrigatório etc. O objetivo desta pesquisa consiste em averiguar as principais modificações ocorridas na prova dos 100 metros rasos masculino, desde a sua origem até os dias atuais. Esta pesquisa, de caráter histórico-bibliográfico, tem a finalidade de resgatar a história da prova dos 100 metros rasos com base na história dos Jogos Olímpicos, verificando as alterações em suas regras básicas, em sua composição e técnicas específicas, a fim de reunir subsídios para o seu ensino em aulas de Educação Física. Com esta pesquisa, esperamos contribuir não apenas com o resgate da história desta ocorridas na prova dos 100 metros rasos masculino, desde a sua origem até os dias atuais. Esta pesquisa, de caráter histórico-bibliográfico, tem a finalidade de resgatar a história da prova dos 100 metros rasos com base na história dos Jogos Olímpicos, verificando as alterações em suas regras básicas, em sua composição e técnicas específicas, a fim de reunir subsídios para o seu ensino em aulas de Educação Física. Com esta pesquisa, esperamos... (Resumo completo, clicar acesso eletrônico abaixo)