Orientador: Sérgio Augusto Cunha / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Educação Física / Made available in DSpace on 2018-08-22T12:25:32Z (GMT). No. of bitstreams: 1 Rodrigues_AnaCarolinadeMelloAlves_M.pdf: 2144136 bytes, checksum: d441e8c33daa046aa1f2cfd67d18b720 (MD5) Previous issue date: 2013 / Resumo: A análise do desempenho muscular por dinamometria hipocinética comumente utiliza-se de valores de torque máximo de quadríceps e isquiotibiais. Porém com a utilização dos valores de torque em função da amplitude de movimento, bem como o cálculo da potência e do desequilíbrio muscular desta maneira torna possível observar o comportamento muscular e a capacidade de estabilização do joelho ao longo de toda amplitude de movimento, e possibilita identificar amplitudes que há risco de lesão de LCA. O objetivo deste estudo foi analisar a série temporal da produção de torque do quadríceps e dos isquiotibiais e calcular a potência e o desequilíbrio muscular de atletas de futsal feminino em função do ciclo de movimento de flexão e extensão do joelho no membro dominante. A amostra foi composta de 19 atletas amadoras de futsal feminino, com idade média de 20 ± 2,83 anos. A avaliação consistiu em 2 série de 5 repetições máximas de extensão/flexão do joelho unilateral de forma concêntrica, em 2 velocidades angulares (180°·s-1 e 210°·s-1) através de um dinamômetro isocinético (Biodex System Pro4). As análises foram baseadas nos valores de torque e potencia do quadríceps e dos isquiotibiais em função da amplitude de movimento, e foram calculadas a razão entre essas musculaturas em função da amplitude de movimento. Foram comparados os valores de torque, potência e razão em função do ângulo do joelho, para ambas as velocidades através da ANOVA e teste de Tukey post hoc. As variáveis foram analisadas em rotinas de ambiente Matlab®, com o valor de significância de 5%. Os valores de torque e potencia do quadríceps apresentaram-se maiores de 40% a 80% do ciclo de movimento nas velocidades de 180°·s-1 e 210°·s-1 que corresponde aos ângulos de 50° a 70° de flexão do joelho. Os valores do torque dos isquiotibiais foram maiores de 80% a 100 % do ciclo, que corresponde aos ângulos de 70° a 80° de flexão do joelho em ambas as velocidades, enquanto que a potencia dos isquiotibiais foi constate até 70% do ciclo, com menores valores de 70% a 100% do ciclo, que corresponde aos ângulos de 65° a 80° de flexão do joelho. Com relação a razão em função do ciclo de movimento, 6 atletas apresentaram em algum instante do ciclo de movimento valores abaixo de 60% na velocidade de 180°·s-1, e 4 atletas a 210°·s-1. O estudo mostra que análise do torque, potência e razão ao longo do ciclo de movimento caracteriza melhor o desempenho muscular destas atletas e identifica desequilíbrios entre isquiotibiais e quadríceps que poderiam não ser encontrados com o método de análise convencional, além de fornecer informações sobre desempenho em ângulos específicos do movimento de flexão e extensão do joelho que podem ser utilizados no treinamento e reabilitação destes grupos musculares / Abstract: The analysis of the muscle performance by isokinetic dynamometry is commonly used by peak torque of quadriceps and hamstrings. However, with the use of the torque values as a function of the amplitude of motion, as well as the calculation of the power and muscle imbalance in this way makes it possible to observe the behavior and the ability muscular stabilization of the knee over the entire range of motion, and helps identify amplitudes there is risk of ACL injury. The aim of this study was to analyze the time series of the torque production of the quadriceps and hamstrings and calculate power and muscle imbalance of female soccer athletes due to the cycle of movement of flexion and knee extension limb dominant. The sample consisted of 19 athletes amateur futsal, mean age 20 ± 2.83 years. The evaluation consisted of two series of five repetitions maximum extension / flexion of the knee-sided concentrically in two angular velocities (180°·s-1 e 210°·s-1) using an isokinetic dynamometer (Biodex System Pro4) . The analyzes were based on the values of torque and power of the quadriceps and hamstrings due to the range of motion, and we calculated the ratio of these muscles due to the range of motion. We compared the values of torque, power and reason as a function of knee angle for both speeds by ANOVA and Tukey post hoc. The variables were analyzed in Matlab ® routines, with the significance level of 5%. The values of torque and power of the quadriceps were higher than 40% to 80% of the cycle of motion at speeds of 180°·s-1 and 210°·s-1 which corresponds to angles of 50° to 70 ° of flexion knee. The hamstring torque values were greater than 80% to 100% duty cycle, corresponding to angles of 70° to 80° of knee flexion at both speeds, whereas the power hamstring muscles were finds up to 70% of the cycle, lower ratios of 70% to 100% duty cycle, corresponding to angles of 65° to 80° of knee flexion. Regarding the ratio as a function of the movement cycle 6 athletes had at some point in the movement cycle values below 60% at a rate of 180°·s-1 and athletes 4 at 210°·s-1. The study shows that analysis of the torque, power and reason throughout the movement cycle is a better muscle performance of athletes identifies imbalances between hamstring and quadriceps that could not be found with the conventional method of analysis, in addition to providing information about performance specific angles of flexion and extension of the knee that can be used in the training and rehabilitation of such muscle groups / Mestrado / Biodinamica do Movimento e Esporte / Mestra em Educação Física

The agricultural tractor allows to move and to pull machines and implements used during the execution of the activities to field. One of the largest problem refers to the acting of the tractor, the reason of a lot of questions between farmers and manufacturing companies. The perfomance determination is a much complex task, mainly when realized in field level, because the variables that should be analyzed are countless, inside of an extremely wide context. The solution found by a lot of researchers was the standardization through testings realized in concrete track, what shows unreliable results about the perfomance of the tractor in the field, besides they can be expensives. The aim of this work was to previse, through dynamometrics tests, the perfomance of an agricultural tractor of wheels in track and in the field, without appeal to the direct tests. The experiment was conducted in Federal University of Santa Maria, submitting a instrumented tractor to dynamic tests of traction in a paved surface and in the field, besides static tests, using an electric dynamometer with Foucault current. Through the use of equations, already conceptualized, was possible to create a interrelation between the following variables: torque and power of the engine, resistance to the rollover, wheel slipping, relation between the transmission relation and the tires dimensions, providing a way to estimate the power developed in the traction bar and the fuel consumption, with subsequent comparison with the dynamic tests. It was found by the correlation analysis, using obtained and estimated values, that there was a high correlation coefficient between the power traction observed in the track and in the field, relative to the estimated power (0.99 and 0.98) respectively.The equations estimating the fuel consumption presented a high adjustment for 90%, obtaining variation between the field treatments and the track in order to 1,19% and 2,09% respectively. Therefore, the estimate of the tractor performance can be made with high accuracy, just doing the dynamometric tests in laboratory, substituting the dynamic tests of field and track. / O trator agrícola permite movimentar e tracionar máquinas e implementos utilizados durante a realização das atividades a campo. Um dos maiores problemas refere-se ao desempenho do trator, razão de muitos questionamentos entre agricultores e empresas fabricantes. A determinação do desempenho é uma tarefa bastante complexa, principalmente quando realizada em nível de campo, pois inúmeras são as variáveis que devem ser analisadas, dentro de um contexto extremamente amplo. A solução encontrada por inúmeros pesquisadores foi a padronização através de ensaios realizados em pista de concreto, o que remete a resultados pouco precisos referindo-se ao comportamento do trator a campo, além de serem dispendiosos. O objetivo deste trabalho foi prever através de ensaios dinamométricos, o desempenho de um trator agrícola de rodas em pista e a campo, sem recorrer aos ensaios diretos. O experimento foi conduzido na Universidade Federal de Santa Maria, submetendo um trator instrumentado a ensaios dinâmicos de tração em superfície pavimentada e campo, além de ensaios estáticos, utilizando um dinamômetro elétrico de corrente de Foucault. Através do uso de equações, já conceituadas, pôde-se realizar a inter-relação das seguintes variáveis: torque e potência do motor, resistência ao rolamento, patinamento, relação de transmissão e dimensões dos pneus, obtendo-se uma estimativa da potência desenvolvida na barra de tração e consumo de combustível, com posterior comparação aos ensaios dinâmicos. Verificou-se através da análise de correlação, utilizando os valores obtidos e estimados, que houve um elevado coeficiente de correlação entre a potência de tração observada no campo e pista em relação à potência estimada, (0,99 e 0,98) respectivamente. As equações de estimativa do consumo de combustível apresentaram um ajuste superior a 90%, obtendo variação entre os tratamentos de campo e pista na ordem de 1,19% e 2,09% respectivamente. Portanto, a estimativa do desempenho de um trator pode ser feita com elevada exatidão, realizando-se o ensaio dinamométrico em laboratório, substituindo desta forma, os ensaios dinâmicos de campo e pista.

While conventional turbines have been extensively researched and tested, Tesla and boundary layer type turbines have not. In order to construct a dynamometer, thermodynamic flow apparatus and future turbines, we modeled the Tesla turbine using theoretical calculations and preliminary experiments. Thus a series of experiments were run to determine stall torque and maximum run speed for a known pressure range. This data was then applied to modeling formulas to estimate stall torque over an extended range of variables. The data were then used to design an appropriate dynamometer and airflow experiment. The model data also served to estimate various specifications and power output of the future turbine. An Obi Laser SSTG‐001 Tesla turbine was used in the experiments described. Experimental stall torque measurements were conducted in two stages. Shaft speed measurements were taken with an optical laser tachometer and Tesla turbine stall torque was measured using a spring force gauge. Two methods were chosen to model Tesla turbine stall torque: 1) flow over flat plate and 2) free vortex with a sink. A functional dynamometer and thermodynamic apparatus were constructed once the model was confirmed to be within the experimental uncertainty. Results of the experiments show that the experimental turbine at 65 PSI has a speed of approximately 27,000 RPM and a measured stall torque of 0.1279 N‐m. 65 PSI is an important data point because that data set is the cut‐off from laminar to turbulent flow. Thus at 65 PSI, a rejection of the null hypothesis for research question one with respect to the flow over flat plate method can be seen from the data, while the vortex model results in a failure to reject the null hypothesis. In conclusion, the experimental turbine was seen to have a laminar and a turbulent flow regime at different air pressures, rather than the assumed laminar flow regime. As a result of this model work, a new Tesla turbine of different dimensions was designed to adjust for flaws in the experimental turbine. The theoretical stall torque models were then applied to the new Tesla turbine design. Results of the models show that the vortex model sets the upper bound for theoretical stall torque for the new and the flat plate flow model sets the lower bound.

Orientador: Antonio Carlos de Moraes / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Educação Física / Made available in DSpace on 2018-08-26T22:48:29Z (GMT). No. of bitstreams: 1 Gaviao_KellyCristina_M.pdf: 2542214 bytes, checksum: b165bdb8314f9d07e2bdb39460e1f45f (MD5) Previous issue date: 2015 / Resumo: O presente trabalho teve como objetivo verificar a influência de oito semanas de sessões de Método Pilates nas respostas eletromiográficas e pico de torque da musculatura abdominal, em jovens do sexo feminino. Foram selecionadas para o estudo 20 voluntárias universitárias, com idade entre 18 e 25 anos, fisicamente ativas, que foram classificadas, aleatoriamente, em dois grupos: Grupo experimental (GE) e grupo Controle (GC). As voluntárias do grupo experimental foram submetidas a oito semanas de treinamento utilizando exercícios do Método Pilates no solo (MAT Pilates), enquanto as voluntárias do grupo controle não receberam intervenção. Antes e após as oito semanas de treinamento, todas as voluntárias foram submetidas à avaliação isocinética da musculatura abdominal por meio do dinamômetro isocinético da marca BIODEX® e avaliação eletromiográfica da musculatura abdominal utilizando eletrodos (superfície) ativos e o Sistema de Aquisição e Análise de Sinais MP150 da BIOPAC System, contendo 16 canais. Os músculos abdominais foram analisados de forma conjunta e os eletrodos de superfície foram posicionados bilateralmente no ventre dos músculos reto abdominal, fibras superiores e inferiores, e músculos oblíquo externo abdominal. Os dados dos sinais eletromiográficos brutos foram expressos em RMS (root mean square). Os dados obtidos após o treinamento foram comparados com os dados obtidos no período pré-treinamento e aos dados obtidos na avaliação do grupo controle. Os valores referentes ao protocolo realizado no dinamômetro isocinético, expressos em newton metro (Nm), foram baseados no pico de torque de cada voluntária durante a execução do teste. Foi empregada a análise de variância (ANOVA) seguida de post hoc de Tukey. A significância estatística adotada foi de 5% (p < .05). Paras valores referentes ao protocolo de eletromiografia, expressos em root-mean-square (RMS), foi empregada a análise de variância (ANOVA). A significância estatística adotada foi de 5% (p < .05). Foi possível observar que os maiores valores de pico de torque de flexão de tronco foram encontrados nos indivíduos do grupo experimental quando comparados ao grupo controle após a realização do protocolo, porém sem diferença significativa nos valores de pico de torque da extensão de tronco. Para os dados de ativação de fibras musculares, houve aumento significativo na ativação da musculatura abdominal analisada do grupo experimental, após a realização do protocolo e quando comparado ao grupo controle. Em conclusão, o protocolo utilizado teve influência positiva no fortalecimento e ativação de fibras da musculatura abdominal analisada / Abstract: The purpose of this study was to verify the influence of eight weeks of Pilates sessions in electromyographic responses and peak torque of the abdominal muscles in young women. Twenty female university volunteers, aged between 18 and 25 years old, physically active participated in this investigation and were divided randomly into two groups: experimental group (GE) and control group (GC). The volunteers of the experimental group underwent eight weeks of training using the Pilates Method exercises on the ground (MAT Pilates), while the volunteers in the control group received no intervention. Before and after eight weeks of training, all the volunteers were submitted to isokinetic abdominal muscles evaluation using an isokinetic dynamometer (Biodex®), also electromyographic activity of the abdominal muscles using active electrodes (surface) using the Data Acquisition System MP150 (BIOPAC System) with 16 channels. The abdominal muscles were analyzed together. The surface electrodes were placed bilaterally in the rectus abdominis muscles, upper and lower fibers, and obliquus externus muscles. Data from raw electromyographic signals were expressed in RMS (root mean square). The data obtained after training were compared with the data obtained in the pre-training period and also obtained in the evaluation of the control group. The values regarding the protocol performed at the isokinetic dynamometer expressed in newton meters (Nm), were based on peak torque of each volunteer during the test run. Analysis of variance (ANOVA) followed by post hoc Tukey was used. The used statistical significance was 5% (p <.05). For figures on electromyography protocol, expressed in root-mean-square (RMS), we used analysis of variance (ANOVA). The statistical significance used was 5% (p <.05). It was observed that the highest peak values of trunk flexion torque were found in the subjects in the experimental group compared with the control group after the completion of the protocol, but with no significant difference in the peak torque values of trunk extension. For muscle fiber activation data, there was a significant increase activation of the abdominal muscles analyzed in the experimental group after the completion of the protocol and compared to the control group. In conclusion, the protocol used had a positive influence in strengthening and activation of the abdominal muscles analyzed fibers / Mestrado / Biodinamica do Movimento e Esporte / Mestra em Educação Física

The aim of this thesis is the innovation of the testing device which is located in Institute of Machine and Industrial Design laboratory. The innovation relates to the portal construction design, where will be placed the hydraulic pulsator from the company INOVA Praha Ltd. New portal construction will be designed with respect to specified parameters and requirements and also with regard to the performed tests (damper tests, vibroizolated properties magnetorheological valves tests etc.). The thesis contains detailed analysis of the current tester and detailed analysis of similar machines with focusing on the portal structure and ways of positioning the crossmember. Further parts of the thesis is a detailed description of the design solution, including the computational simulations, attached drawing documentation and experimentally verified functional sample (crossmember).

This Diploma Thesis is dedicated to solve the source of noise, observed during braking processes on tested vehicle, called Gouki noise and has been worked out in corporation with Federal Mogul company. The aim of this work to create test methology, which allows to experimentally detect the source of undesirable noise and eventually suggest next steps in its prevention.

The theses presented proposes an innovation of load test stand for electric drives. It begins with a general overview of load test stand types, their manufacturers and measurement methods in load and no-load situations. Next part analyses current circuit diagram of the load test stand and its risks. This is followed by a proposal for innovation of the circuit diagram which is divided into electrical and control part using current load test stand and its mechanical parts. A wiring diagram is created, the control part is processed by the Logosoft program. The design is evaluated from the safety point of view and modified to meet applicable technical standards.

In the recent past, as more farm power is being demanded on farms, due to increased farm sizes and operating speeds, larger and heavier farm machines are deployed in various farming operations. Their cumulative negative effects have become more apparent with increased incidences of soil compaction problems. This has forced many farmers to practice deep tilling, using subsoilers to break up compacted subsoil layers. In some maize growing regions of South Africa, conventional subsoilers are used in a tandem configuration. The farmers believe that the use of subsoilers in this mode reduces the draft force per unit area tilled. This probably happens because the critical depth for the rear subsoiler is increased beyond its working depth of 600 mm. Operating in this mode necessitated this study, with the ultimate goal of testing an appropriate existing force model for a single tine in predicting the force requirements of the front subsoiler in a tandem configuration. Secondly, to develop an alternative model for the rear subsoiler based on the three-dimensional failed soil-profile and to determine the relative position of the front subsoiler at which energy utilization is optimized. To develop the proposed model, an analytical approach based on limit equilibrium analysis was used and a Matlab-based computer program was coded to solve it. Its verification was conducted through field experiments in sandy clay loam soil. The experiments consisted of a continuous measurement of the horizontal and vertical forces acting on each subsoiler by a two-dimensional force transducer system. At the same time, the three-dimensional and thus the cross-sectional areas of the disturbed soil-profiles at different sections were measured, as well as the soil characteristics. A manual method employing a pin-profile meter was used to measure the vertical cross-sectional areas of the failed soil-profiles at 100 mm intervals. Further more, a technique using an automatic penetrometer and a computer program was developed to identify and map the three-dimensional failed soil-profiles. This technique indicated that the subsoiler failed the soil beyond its maximum operating depth and width. The results also indicated that the soil-failure pattern at close spacing is in phase at both subsoilers, leading to reduced total draft force requirements. At a wider spacing, the soil-failure pattern was out of phase, thus resulting in increased total draft force requirements. At the same time, the cross-sectional area tilled per unit draft force increased with increased spacing. This was because the failed maximum cross-sectional area increased in size faster than the total draft force as the spacing was increased. The proposed model verification results show that the predicted and recorded forces at the rear subsoiler correlated reasonably well at a wider spacing. When the front subsoiler was shallow working and close to the rear subsoiler, the model under- predicted the measured forces on the rear subsoiler, whilst the Swick-Perumpral model over predicted the applied forces to the front subsoiler and this was generally the case at wider spacings. Furthermore the efficiency of the subsoilers was maximized when the longitudinal spacing was such that it allowed the soil failed by the front subsoiler to stabilize before the rear subsoiler reached it. The maximum cross-sectional area failed per unit draft force was recorded when the depth of the front subsoiler was equal to about 80% of the rear subsoiler-operating depth. The knowledge contributed by this research will not only facilitate qualitative field operations and optimize energy use, but also promote better management decisions. / Thesis (PhD (Engineering))--University of Pretoria, 2004. / Civil Engineering / unrestricted

No description available.

In the manufacturing industry, the mechanics of metal-cutting is well-understood and used to improve cutting processes. The mechanics of wood-cutting are still in its early stages and further research is required. Although there is a lack of knowledge regarding cutting mechanics for wood, today's cutting speeds in modern sawmills are as high as 100 m/s and the production rate and quality are high, to the cost of unnecessary wood-based waste. To be able to reduce waste it is necessary to understand the process of wood machining in detail. A Kistler 9129AA dynamometer was commissioned in a custom rotation machine and compared to an already existing sensor. It was shown that there were significant deviations between the measurement results of the evaluated sensor system and the Kistler 9129AA dynamometer. In this specific setup, the Kistler dynamometer was not able to deliver the same results as the existing sensor system. Therefore, the eligibility of the Kistler 9129AA dynamometer to measure cutting forces in wood could not be concluded.