Zugl.: Braunschweig, Techn. Univ., Diss., 2008

Bachelor-Arbeit Univ. St. Gallen, 2005.

Atualmente são utilizados diversos equipamentos e implementos para treinamento de força. Os flexores do cotovelo apresentam enorme variedade de exercícios, cada qual apresentando diferentes características de torque externo. Na maioria dos casos, a escolha dessa característica aparenta não seguir nenhum critério pré-estabelecido para sua determinação, sendo que a variação desse torque externo é fator causador de grande influência na adaptação do músculo ao treinamento imposto. Com isso, a escolha de um exercício demanda conhecimento dos objetivos de treino, além do conhecimento das características musculares, no que diz respeito à possibilidade de produção de força e torque musculares. Esse estudo objetivou verificar o comportamento do torque muscular de flexão do cotovelo de indivíduos ativos e sedentários, comparando-os com a característica de torque externo de quatro exercícios usuais de flexão do cotovelo (Rosca Direta, Rosca Scott, Rosca Banco Inclinado e Rosca Polia). Além disso, visou-se comparar a capacidade de produção de torque entre as três posições da articulação rádio-ulnar. Assim, foi avaliado o torque concêntrico máximo de flexão do cotovelo, numa velocidade de 45º/s, num dinamômetro isocinético. A amostra contou com 20 universitários jovens e saudáveis, divididos nos dois grupos. As relações torque-ângulo encontradas para o grupo de ativos não apresentaram pico de torque e, sim, um platô que se prolonga por grande parte da relação. As relações torqueângulo encontradas para o grupo de sedentários apresentam um pico definido, ocorrendo, em média, entre 32º e 43º de flexão do cotovelo, porém com grande variabilidade. Não foram encontradas diferenças estatisticamente significativas entre as posições da articulação rádioulnar com relação à: ângulo de pico, taxa de acréscimo, taxa de decréscimo, torque final (sedentários) e torque absoluto. Apenas o grupo de ativos apresentou diferenças significativas entre as posições com relação ao torque final. Não foram encontradas diferenças estatisticamente significativas entre os grupos com relação à: taxa de acréscimo e torque final. Houve diferenças significativas entre os grupos com relação à taxa de decréscimo, em todas as posições da articulação rádio-ulnar. Nenhum dos exercícios avaliados parece apresentar uma característica de torque externo condizente com quaisquer relações torque-ângulo encontradas nesse estudo. Assim, foi sugerida uma polia assimétrica, com raio variando de acordo com as taxas de variação média de torque encontradas na amostra, produzindo, assim, um torque externo que acompanha as características de produção de torque muscular. Nesse estudo, foi possível concluir que existe grande variabilidade com relação às variáveis inerentes às características de produção máxima de torque flexor do cotovelo. Assim, é possível que se faça inferências com relação à adaptação funcional obtida com o treinamento, o qual levaria a musculatura a apresentar um pico de torque mais bem definido e próximo aos 90º de flexão do cotovelo. Por outro lado, o sedentarismo faria com que o ângulo de maior produção de torque muscular se aproxime da extensão do cotovelo, numa característica de produção de força condizente com o trecho ascendente da relação forçacomprimento, atuando num ciclo alongamento-encurtamento. / Nowadays there are many types of equipment used to strength training. Especially the elbow flexors present great variety of exercises, each one with different resistance moment characteristics. In the majority of the cases, this characteristic of resistance moment does not seem to follow any criterion for its determination and its variation is a causing factor of great influence in the muscle adaptation to the imposed training. Thus, the exercise choice demands to know the objectives of the training and muscle characteristics, in respect to the possibility of muscle force and moment production. This aim of this study was to verify the elbow flexor muscle moment profile of actives and sedentary subjects, comparing it with resistance moment characteristics of four usual exercises of elbow flexion (Barbell Biceps Curl, Scott Biceps Curl, Lying Dumbbell Curl and Standing Cable Curl). Moreover, it was aimed to compare the moment production capacity between three forearm positions. Thus, it was measured maximal concentric elbow flexion moment, at 45º/s, on an isokinetic dynamometer. The sample was composed by 20 young and healthy students, divided in two groups. The moment-angle relationship founded in the active group did not show a moment peak, but a plateau that prolongs for great part of the relationship. The moment-angle relationship founded in the sedentary group showed a defined peak, occurring, on average, between 32º and 43º of elbow flexion, however with great variability. It was not founded statistic differences between forearm positions in relation to: moment peak angle, moment increase rate, moment decrease rate, final moment (sedentary) and absolute moment. Only the active group shown statistic differences between positions in relation to final moment. It was not founded statistic differences between groups in relation to: moment increase rate and final moment. There was statistic difference between groups in relation to moment decrease rate, in all forearm positions. None of the evaluated exercises seems to show an external moment characteristic suitable with any moment-angle relationship founded on this study. Thus, it was suggested an asymmetrical pulley, whose radius variation fit well with increase and decrease rates founded at this sample, producing, in this way, an external moment suitable with the capacity of muscle moment production. In this study, it was possible to conclude that occur great variability in respect to the variables inherent to the characteristics of maximal elbow moment flexion production. Thus, it was possible to infer in relation to functional adaptation gotten with the training, which would lead the muscle to present a most defined moment peak and closer to 90º of elbow flexion. Nevertheless, the sedentary would lead the moment peak angle closer to elbow extension, which force production characteristic would be suitable with the ascending limb of force-length relationship, undergoing a stretch-shortening cycle.

To describe learning, as an alternative to a neural network recently dynamical systems were introduced whose vector fields were plastic and self-organising. Such a system automatically modifies its velocity vector field in response to the external stimuli. In the simplest case under certain conditions its vector field develops into a gradient of a multi-dimensional probability density distribution of the stimuli. We illustrate with examples how such a system carries out categorisation, pattern recognition, memorisation and forgetting without any supervision.

This diploma thesis focuses on the topic of engine and chassis dynamometers. Emphasis is given to historical development as well as current findings in this field, especially in field of motorcycle dynamometers. This diploma thesis also describes the motorcycle engine and its main structural parts. The practical part of this diploma thesis deals with measuring motorcycle parameters by using a chassis dynamometer. These parameters have been measured with various combinations of air filters and exhaust silencers. In the evaluation process, results based on measurements have been displayed as graphic dependences. The discussion part goes on and presents recommendations and proposals for the practical use of the motorcycle. These proposals and recommendations are based on measured values.

Master thesis deals with the link between the internal and external parameters of the combustion engine. Its point is not to exactly define this links but only check if this links exist and what is their character. First part of the thesis is dedicated to present state of the mixture preparation systems of the petrol engines. Here are described the ways of the lambda regulation and its effect of the specific fuel consumption. Further are described types of injection systems and at the end is described the way for the determination of the ignition advance. Second part is focused on the chosen mathematics-statistics methods which are interesting and useful for the solving this problem. Last part is paid to the verification of the existence the links of the operating parameters and attempt of their definition in numeric way using the Maple software and chosen mathematics-statistics methods.

This thesis describes the various methods for measuring the performance parameters of petrol engines and on the selected engine (car) evaluate their accuracy with regard to the economic complexity of the methods. In the first part of this thesis is described construction of combustion engines, explained the importance of individual performance parameters (power, torque, specific fuel consumpti-on) and characteristics combustion engines. This section, however, is focused on the issue of performance measurement, using both static and dynamic methods of measurement. The second part examined the various methods of measurement in practice on selected engine (car) with an assessment of their advantages and disadvantages and the financial cost of the-ir implementation.

The thesis deals with the performance measurement of tractor engine through four used different methods. In the first theoretical part of thesis is analysis engine design with its main groups and the second part explains methods of measuring performance and measuring equipment. In the practical part of thesis is the explained methodology of applied methods of measurement, together with their evaluation. The first applied method is performance measurement on the dynamometer, the second method is measurement of these parameters during free acceleration, the third method is measurement of parameters during free acceleration with load and fourth method is measurement of parameters using GPS. In conclusion of this part is to compare the results of each used measurement methods between themselves and the conclusions drawn from it.

Diploma thesis focuses on fuel for spark-ignition engines and their operational cha-racteristics. First chapters of the thesis focus on requirements of these fuels and their production, followed by details analysis of the octane number, ways of measuring it and demands towards the octane number for usage in modern petrol engines. Next part describes individual fuel types used to run spark-ignition engines and their pros and cons. Analysis of exhaust emission particles produced during fuel combustion and it's regulation is covered in the next part. Final chapter provides a comparison of the in-fluence, octane number of the fuel has on the vehicle performance, based on data mea-sured in certified rollway test room. The results of the measurement were used to pro-duce tables and charts to visually display them.

This diploma thesis deals with the influence of gearbox design on passive losses of passenger cars. First chapters are focused on theory of construction of transmission and determination of vehicle resistance opposing its movement. Experimental work concerns measurement on chassis dynamometer and brings comparison of obtained values. The last chapter analyzes financial issues of different design of gearboxes installed in identical cars.