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In golf, a range of shot types are necessary for successful performance, with driving and iron-play constituting the long-game. It is possible to vary long-game shots through altered trajectory, for example, by utilising right-to-left or left-to-right ball flight curvature, providing course management advantages. However, how golfers vary their biomechanics to achieve different trajectories is not scientifically understood. Therefore, the purpose of this thesis was to biomechanically investigate different trajectories hit with the same club. To investigate shot trajectories, accurate measures of performance were necessary. Launch monitors (TrackMan Pro IIIe and Foresight GC2+HMT) are bespoke technologies capable of tracking the clubhead and ball through impact. However, their accuracy for scientific research has not been independently validated. Therefore, a novel purpose-designed tracking method was developed using a three-dimensional optical tracking system (GOM). The accuracy of this method was validated and the system used as the benchmark to which the two launch monitors were compared through limits of agreement. The results showed, in general, the launch monitors were in closer agreement to the benchmark for ball parameters than clubhead. High levels of agreement were found for ball velocity, ball path, total spin rate and backspin. However, poorer agreement was shown for ball sidespin and spin axis as well as clubhead velocity, clubhead path and clubhead orientation. Consequently, the launch monitors were deemed unsuitable for inclusion in scientific research across a range of impact parameters. Draw and fade trajectories with a driver and draw, fade and low trajectories with a 5-iron were investigated biomechanically. The clubhead and ball were tracked using the optical method developed in this thesis. Key biomechanical variables (address position and whole-swing) were defined based on coaching theory. Statistically, analysis of variance (address) and principal components analysis (whole-swing), were used to compare draw against fade and low against natural trajectories. Multivariate correlation was used to identify swing pattern similarities between golfers. The group-level comparison showed draw-fade address differences whereby for draw trajectories, the ball was positioned further away from the target, the lead hand further towards the target and the pelvis, thorax and stance openness closed relative to the target line. Over the whole-swing, the draw when compared to the fade demonstrated a pelvis rotation, more rotated away from the target with later rotation; lumbar forward flexion, with slower extending in the downswing; lumbar lateral flexion, with more flexion towards the trail throughout and prolonged trail flexing through ball contact; thorax lateral flexion, with greater, slower lead flexing in the backswing and greater, more prolonged trail flexing in the downswing; pelvis translation further towards the target throughout, with earlier forward translation and centre of pressure, with an earlier, quicker, greater forward shift. Cluster differences were evident, with both Clusters I (57% of golfers with the driver) and II (71% of golfers with the 5-iron) showing greater, earlier thorax rotation towards the target and a tendency for greater lumbar forward flexion over the whole-swing (Cluster II) and backswing (Cluster I). For the group-level low-natural comparison, golfers positioned the ball further away from the target and their lead hand further towards the target for low trajectories. Further, Cluster IV (45% of golfers), narrowed their stance width and laterally flexed their thorax towards the lead, for the same trajectories. Over the whole-swing, the low when compared to the natural showed the pelvis translated towards the target throughout, with later, lesser forward shift for the low trajectories. Furthermore, centre of pressure displayed a greater forward shift for the same shots. Finally, both clusters (Cluster III 36% of golfers and Cluster IV) differed in lumbar forward flexion when playing low trajectories; over the backswing, Cluster III extended, whereas Cluster IV flexed. Cluster IV also showed greater extending in the downswing. Finally, Cluster IV showed more lumbar lateral flexion towards the lead throughout. The results of this study have implications for scientific researchers as well as golf coaches, club-fitters and professionals. Commercially available launch monitors appear accurate enough for coaching applications, however caution is needed for scientific research when tracking a range of clubhead and ball parameters. Furthermore, changes in biomechanics when playing different trajectories has implications for future research and interpretation of published work, as well as for coaching theory. Future work following this thesis could utilise the optical tracking method to validate further commercial systems and for more detailed experimental investigation of clubhead-ball impacts. Furthermore, additional biomechanical investigation into a wider range of shot trajectories across more variables could be conducted, with a more in-depth understanding gained from principal components analysis and golfer clustering.

Submitted by Marcos Samuel (msamjunior@gmail.com) on 2017-02-09T12:08:18Z No. of bitstreams: 1 Dissertação_Luis Carlos Moreno.pdf: 1851298 bytes, checksum: f9907551df010d1d88bf2f0c7996d153 (MD5) / Approved for entry into archive by Vanessa Reis (vanessa.jamile@ufba.br) on 2017-02-09T14:46:10Z (GMT) No. of bitstreams: 1 Dissertação_Luis Carlos Moreno.pdf: 1851298 bytes, checksum: f9907551df010d1d88bf2f0c7996d153 (MD5) / Made available in DSpace on 2017-02-09T14:46:10Z (GMT). No. of bitstreams: 1 Dissertação_Luis Carlos Moreno.pdf: 1851298 bytes, checksum: f9907551df010d1d88bf2f0c7996d153 (MD5) / Para modelar o problema, é usada a abordagem de Euler-Lagrange. A qual se aplicou a um kit experimental nomeado Ball-Balancer, de modo que pudera-se obter um conjunto de equações dinâmicas que representem, no espaço de estados, seu comportamento dinâmico completo. Algumas suposições foram feitas sobre a situação experimental para evitar assim uma excessiva complexidade e ter que lidar posteriormente com fortes não linearidades que tornarem ao modelo num caso de estúdio difícil de aplicar. Um esquema de controle adaptativo direto é aplicado a um kit Ball-Balancer, usado como planta não linear. A estabilidade do sistema em malha fechada, e o seu desempenho no rastreamento são discutidos sob o enfoque de Lyapunov, também a obtenção de uma lei de controle adequada, assumindo parâmetros conhecidos, posteriormente, utilizando a mesma metodologia foi obtido um conjunto de equações de adaptação de parâmetros que procuram precisão no seguimento do sinal, em presença de não linearidades desconhecidas. A aplicabilidade e funcionamento do algoritmo de controle desenvolvido é implementado por meio de simulação, utilizando Matlab e Simulink para executar o controlador não linear sob uma abordagem de Controle Adaptativo por Modelo de Referência (MRAC), obtendo alguns resultados satisfatórios, como a teoria prever.

This work describes the modeling, control design, and experimental verification of an electromagnetic suspension system with position feedback using infrared sensors. A nonlinear model is obtained by fitting a first principle analytical model of the system to experimental data. A sliding control strategy is designed using a sliding surface derived from the model to achieve robust stabilization for the closed-loop system. The control is then implemented on an embedded commercial DSP system for experimental verification of the designed control on a laboratory scale electromagnetic suspension system. To compensate for the steady-state tracking error, two modifications are considered. In the first method, a small magnitude integral term is added to the error feedback, equivalently adjusting the reference signal and eliminating the constant bias. In the second method, an integral sliding control is considered, using a higher-order sliding surface, which also eliminates the constant bias. The experimental results show the efficacy of all designed control techniques. The modified techniques, unlike the original design, effectively eliminate the constant position error.

Tennis, like any other practice, undergoes challenges and revisions to its nature. A number of technical and technological innovations have recently been implemented and/or suggested by a variety of interested parties including the introduction of shorter sets and tie-breaker sets, and a revised tennis seeding structure. These innovations, if adopted, will represent a new instantiation of the game. Thus, determining how decisions concerning the future development of the game ought to be made and who ought to make those decisions is of great importance in terms of how fair the decision-making process is and whether the decisions are good for the game itself. In response to these problems we develop a normative account of "fair play" from Macintyre's (1985) nee-Aristotelian position, emphasising the importance of the internal goods, practices, and traditions of tennis, and that decisions ought to be made by those who have relevant experience or knowledge of the practice of elite male tennis. This account, however, fails to provide a decision-making method and is vulnerable to the criticism that it is inherently conservative. We consider three theses that might fill this lacunae and from which a rational decision-making method to evaluate technical and technological innovations in elite male tennis could be developed. First, we consider Rawls's (1971) method of "reflective equilibrium" which allows us to clarify issues, and is both systematic and democratic, but it is too far removed from actual sporting practices, their ethos, histories and traditions to have any normative force. Secondly, we consider Rawls's (1987) "overlapping consensus" model which is conscious of the political situatedness of decision-making but it is inadequate since the consensuses which it reaches might be based on criteria external to the norms of sporting practices. In order to ensure that the consensus reached is based on a critical consensus of the internal norms of sporting practices, we consider Walzer's (1983) thesis that cultural spheres have internal norms which must be respected and which are the basis for normative judgements about justice or goodness within that practice. This thesis is sympathetic to, yet critical of, the internal goods, practice, and traditions of elite male tennis, and that decisions ought to be made by those who have experience or knowledge of the practice of elite male tennis. We conclude the thesis by presenting a tradition-practice bound decision-making model that can be used to evaluate technical and technological innovations in elite male tennis which is transparent, democratic, and respectful of the traditions and internal norms of tennis.

Os moinhos de bolas são equipamentos presentes em plantas de mineração, sendo uma máquina importante no circuito de cominuição de minérios. Em função de inúmeros fatores como, por exemplo, projeto, fabricação, sobrecarga no equipamento, falta de manutenção e procedimentos de operação inadequados, são desenvolvidas descontinuidades nos componentes estruturais desse equipamento. Os componentes estruturais dos moinhos, basicamente, corpo, tampas e munhões, além do custo elevado, possuem prazos de fabricação que podem variar de dois a três anos dependendo da demanda do mercado. Portanto é cada vez mais necessário que as descontinuidades detectadas nesses componentes sejam corretamente avaliadas. Neste trabalho analisaram-se pela mecânica da fratura a criticalidade de descontinuidades, tais como trincas constatadas em um munhão de um moinho de bolas e compararam-se os valores teóricos de taxa de propagação (crescimento) dessas descontinuidades com valores reais obtidos por meio de inspeções periódicas realizadas neste componente. A nucleação das trincas foi causada por falta de lubrificação nos mancais do moinho, gerando esforços térmicos circunferenciais no munhão, em que a temperatura estimada do contato munhão e bucha atingiu a faixa de 100 °C a 150 °C. No período analisado, os resultados obtidos por meio da norma BS7910 mostraram-se mais próximos dos valores reais do que a norma ASME Seção XI, Apêndice A. O tamanho da trinca mais crítica foi aceito pelos critérios da norma BS7910 e aprovado apenas na condição de emergência da norma ASME Seção XI, Apêndice A. / The grinding ball mills are equipments present in mining plants, being important in the ore comminution circuits. Depending on numerous factors, such as, for example, design, manufacturing, overloads, poor maintenance and inadequate operating procedures, flaws are developed in the structural components of this equipment. The structural components of a mill, basically, shell, heads and trunnions, besides high costs, have lead times that might vary from two to three years, according to market demand. Therefore, it becomes increasingly necessary that any flaws in those components to be properly evaluated. This paper analyzed the fracture mechanics of the criticality of flaws, such as cracks observed in a ball mill trunnion and compared the theoretical values of growth rate of these defects with actual values obtained through periodic inspections performed in this component. The cracks nucleation was caused by lack of lubrication in the trunnion bearings, generating circumferential thermal stresses, thus the estimated temperature of the trunnion and bushing contact achieved the range 100 °C to 150 °C. During the analyzed period, the results obtained by the standard BS7910 proved to be closest to the actual values than the standard ASME, Section XI, Appendix A. The most critical crack size was accepted by the criteria of the BS7910 and approved only on emergency condition of ASME Section XI, Appendix A.

O trabalho apresenta inicialmente os conceitos clássicos de rolamento (sem escorregamento e sem pivotamento) de uma superfície sobre outra usando os triedros de Darboux das duas superfícies ao longo das respectivas curvas de contato. Mostra, ainda, a equivalência desses conceitos com outras definições. A seguir, estuda-se a controlabilidade no problema do rolamento de uma esfera sobre uma superfície S de revolução, tanto no caso de rolar sem escorregar como no caso de não escorregar e não pivotar; a controlabilidade visa determinar a atingibilidade entre dois 'estados' da esfera (posição em S e orientação), isto é, de elementos do espaço das configurações S×SO(3). Na seqüência, estabelecem-se condições nos controles para que os rolamentos sem escorregamento e sem pivotamento ocorram sobre geodésicas de S e obtém-se, também, a controlabilidade nesta situação. Finalmente, verifica-se que, quando S é um plano, 3 ou 4 rolamentos retilíneos, sem escorregamento e sem pivotamento, são suficientes para garantir a atingibilidade entre dois “estados” da esfera. / This work starts by presenting the classical concepts of rolling (without slipping and without slipping or twisting) of a surface over another one, using the Darboux referential frames of the two surfaces along their contact curves. It shows the equivalence between these concepts with other definitions. In the sequel one studies the controllability in the rolling problem of a ball over a surface of revolution S, including both: the non slipping and the non slipping or twisting cases; controllability aims to determine the reachability between two 'states'of the ball (position on S and orientation), that is, two elements of the configuration space S × SO(3). It follows by establishing conditions on controls in order that the rollings occur along geodesics of S and by studying the controllability in this situation. Finally, it is shown that if S is the plane, 3 or 4 retilinear moves without slipping or twisting are enough to guarantee reachability between two states of the ball.

Mechanical Alloying is a manufacturing process that produces alloys by cold welding of powders. Usually, a vial containing both the powder and steel balls is agitated. Due to impact between the balls and balls and the vial, the powder is mechanically deformed, crushed, and mixed at nano-scales. In this thesis, a numerical model is developed to simulate the dynamics of the vial and the grinding balls of the SPEX 8000 ball milling device, a standardized equipment in both industrial and academic investigations of ball milling. The numerical model is based on the Event Driven Method, typically used to model granular flows. The method implemented is more efficient than the discrete element method used previously to study ball milling dynamics. The numerical tool obtained is useful for scale-up and optimization of mechanical alloying of various materials. An optimization study is presented for the SPEX 8000.

In this thesis, called a simulation model of population growth, there was created the simulation model of a population growth in the Czech Republic to the year 2052. First there was constructed the projection through the component method used in demography. Deterministic values obtained by this method are then used in the simulation analysis. In the simulation analysis there was conducted an experiment with three variables which influence the population growth (the fertility, life expectancy/the coefficient of the decline of the probability of the death/ and the migration balance). With the support of the Crystal Ball, supporting program for Excel, which provides the possibility of the simulations, there was determined the stochastic character of the three variables. There are created the low, medium and high variant of the projections, as well as three other possible variants of population growth that might occur. These variations are called economic crisis, friendly migration policy and restrictive migration policy.

The auction is a form of trading, which is becoming more popular in recent years. For English auction the typical object intended for trading is art or antique etc. Auction houses require the most accurate estimates of total sales for each auction because of their economic activity. These estimates are constructed, but the only information that is available is starting price of auctioned objects (paintings). Two methods have been proposed for purpose of this estimation. They are conducted in the application Crystal Ball. Selling prices of the objects are generated in the first method and total sales are estimated with the help of application assignment problem. The second method consists in the simple sum of generated selling prices. The cornerstone of these methods is the distribution from which a coefficient is generated that sets increase of the starting prices to selling prices. The first part of practical application is dedicated to estimating parameters of this distribution. In the second part, total revenues are estimated using both methods. In conclusion there is the assessment of the suitability for both methods and estimated distributions. Method that provides the most accurate estimate of total sales for auction house is determined there also.