Résumé Ce travail de thèse concerne le frottement et la dynamique d’un contact glissant entre deux plans secs et rugueux soumis à une faible charge normale. La vibration normale, et le bruit qui en résulte, sont associés à l’excitation induite au cours du glissement par les deux topographies aléatoires des solides en regard. Des mesures expérimentales de l’accélération verticale d’un patin rugueux soumis à son propre poids et en glissement stationnaire sur une piste rugueuse ont permis d’identifier et de caractériser une transition entre deux régimes : un régime de contact ininterrompu entre les solides à basses vitesses et un régime de sauts pour des vitesses plus élevées. Pour ce dernier, la dynamique est gouvernée par de très nombreux impacts entre aspérités que nous avons caractérisés sur le plan statistique (nombre de chocs, durées entre chocs, forces d’impact, etc.). Ces deux régimes conduisent à des comportements en frottement bien distincts. Une des originalités de cette recherche a été de confirmer les scénarios suggérés par les mesures accélérométriques à l’aide d’une mesure haute fréquence des variations temporelles de la résistance électrique de contact au cours du glissement. En améliorant la résolution temporelle des chocs, ces mesures apportent un éclairage dynamique sur la problématique du contact électrique rugueux. Pour interpréter ces résultats expérimentaux, nous avons revisité le modèle standard du Bouncing Ball. Il décrit une bille soumise à la gravité, et rebondissant sur une table animée d’un mouvement vertical aléatoire, représentatif de l’excitation stochastique induite par les topographies de surfaces en glissement. Nous avons introduit pour la première fois dans le modèle un temps de corrélation pour l’excitation aléatoire et montré son influence sur la dynamique des rebonds. Ce temps de corrélation est directement relié aux longueurs de corrélations des surfaces en contact et à la vitesse de glissement. Ce modèle revisité permet in fine une bonne prédiction de la vitesse de transition entre les deux régimes observés expérimentalement. / This work deals with the friction and dynamics of a sliding contact between two dry and rough surfaces subjected to a low normal load. The normal vibration and the resulting noise are associated with the excitation induced during slip by the random topographies of both solids. Experimental measurements of the vertical acceleration of a rough slider subjected to its own weight and steadily sliding on a rough plate enabled identification and characterization of a transition between two regimes: An uninterrupted contact regime at low speeds and a regime of jumps at higher speeds. For the latter, the dynamics are governed by many impacts between asperities that we have characterized statistically (number of shocks, duration between shocks, impact forces, etc.). These two regimes lead to distinct frictional behaviors. One of the originalities of this research was to confirm the scenarii suggested by the accelerometric measurements through high-frequency monitoring of the temporal evolution of the electrical contact resistance during sliding. By improving the temporal resolution of shocks, these measurements provide a dynamics picture of the problem of rough electrical contact. To interpret these experimental results, we have revisited the standard Bouncing Ball model. It describes a ball subjected to gravity, and bouncing on a table animated by a random vertical motion, representative of the stochastic excitation induced by the topographies of sliding surfaces. We improved the model by introducing a correlation time for the random excitation and showed its influence on the dynamics of the bounces. This correlation time is directly related to the correlation lengths of the surfaces in contact and to the sliding velocity. This revisited model enables a good prediction of the speed at which the transition between the two regimes is observed experimentally.

The main aim of this master's thesis is create golf ball picker with charging station. These two components create the system, which automates process of golf ball collection on driving range. The robot replaces human manual activity in this branch and it eliminates injury. On the other hand, robot respects functional, psychological, ecological and aesthetic demands. It demarcates standard principles of these days and new way how to collect balls on driving range.

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Made available in DSpace on 2017-07-24T19:45:52Z (GMT). No. of bitstreams: 1 Gustavo Trierveiler Anselmo.pdf: 9979848 bytes, checksum: 860bb544a69cc5a636999f5a0f91c142 (MD5) Previous issue date: 2016-09-09 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The Simulator Didactics of Accommodation of the Human Eye is a set of activities that have as objective facilitate the teaching-learning process on optics and, especially, on the process of human accommodation. The educational product explores concepts of geometrical optics (light rays and refraction) in the paraxial approximation and its applications to spherical lenses. Didactic simulator was built with a flexible lens, produced with a latex-made male condom filled with water. Its spherical shape, with a diameter of approximately , was compared with the theoretical model of the “ball lens”. We have experimentally determined its focal length ( and compared it with the corresponding theoretical value, obtaining a accuracy. The flexibility feature of this lens gives the possibility to simulate the accommodation process of the eye in two different situations: for diverging and parallel light beams, corresponding to objects near and far from the observer, respectively. These concepts were addressed in the educational spirit of the meaningful learning of David Ausubel. It has been proposed 4 lesson plans from the previous organizers (taught in 8 lessons), 1 lesson plan for application of the didactic simulator (3 lessons) and 2 meetings for application and discussion of the questionnaires (2 lessons), summing up 13 classes. We have used several resources: lectures, computer simulators, construction of one darkroom, dissection of the bull's-eye and a experimental apparatus produced by students. Adding to other support materials, these instruments facilitated the learning of content offered and the better understanding of the students. This is proven by the results obtained in 42 questionnaires applied. Of these, 24 were before and 18 after the application of the project. There has been an increase of ~200% in the number of hits in the second stage. The proposal has been applied in a class of 39 students, where we had a meaningful learning of over of the class. One should stress also the impact on students, who were more willing to learn, requiring better quality lessons, both in content and evaluation of them. / Esta dissertação descreve um conjunto de atividades realizadas com o objetivo de facilitar o processo de ensino-aprendizagem sobre a óptica e, principalmente, da acomodação do cristalino humano. O produto educacional gerado, chamado de Simulador Didático da Acomodação do Cristalino do Olho Humano, explora conceitos de óptica geométrica (raio de luz e refração) dentro da aproximação paraxial e suas aplicações em lentes esféricas. Para isso foi construído um aparato com uma lente flexível, produzida com preservativo masculino feito de látex preenchido com água. O seu formato esférico, com diâmetro de aproximadamente , foi comparado com o modelo teórico das “ball lens”. Determinamos experimentalmente sua distância focal ( que, comparado com seu valor teórico, tem uma acurácia de . Por ser flexível, foi possível simular o processo de acomodação do cristalino em dois casos: para feixes de luz divergentes e paralelos, simulando situações com objetos próximos e distantes do observador, respectivamente. Estes conceitos foram abordados conforme a concepção educacional da aprendizagem significativa de David Ausubel. Foram propostos quatro planos de aulas de organizadores prévios (ministrado em oito aulas), um plano de aula de aplicação do simulador didático (três aulas) e dois momentos para aplicação e discussão dos questionários (duas aulas), totalizando 13 aulas. Utilizou-se variados recursos: aulas expositivas, simuladores computacionais, construção de câmara escura, dissecação do olho de boi e aparatos experimentais produzidos pelos alunos. Aliados a materiais de apoio, esses instrumentos facilitaram a aprendizagem dos conteúdos ministrados e o melhor entendimento dos alunos. Isso é comprovado pelos resultados obtidos em 42 questionários aplicados. Destes, 24 foram antes e 18 depois da aplicação do projeto. Houve um aumento de ~200% no número de acertos na segunda etapa. A proposta foi aplicada em uma turma de 39 alunos, onde obtivemos uma aprendizagem significativa de mais da classe. A ressaltar, também o impacto nos alunos, que se mostraram mais dispostos a aprenderem, exigindo aulas de melhor qualidade, tanto na exposição do conteúdo como na avaliação.

Toute pratique sportive est dépendante d’un système de règles qui simultanément prescrivent et prohibent. Codifiées, ces règles participent de l’institutionnalisation sportive propre au sport compétitif contemporain. La modalité sportive reposant sur une pratique fédérale, en club, nous intéresse ici. Ce travail de thèse rend compte de la transmission du code du jeu, des représentations sociales des acteurs du sport – pratiquants, entraineurs, arbitres et dirigeants – ainsi que de la gestion de la norme sportive – espaces, durées, règles du jeu – par les institutions référentes. Notre recherche repose sur une approche comparative entre trois sports, distincts par leur degré d’institutionnalisation : le basket-ball, l’escalade et le paintball. Ce travail s’appuie simultanément sur l’usage des observations –séances d’entrainements en club, compétitions –, des entretiens semi-directifs (n = 52) et de la méthode des comparaisons par paires. Il en ressort une perception différenciée de l’application de la règle sportive qui dépend tout autant du niveau d’institutionnalisation – le paintball étant le moins sportifié des trois sports – que des caractéristiques de la pratique (situations sociomotrices ou psychomotrices). La transmission du code du jeu est consubstantielle à une culture en acte de la pratique alors que les représentations sociales se distinguent en fonction de la carrière sportive. La gestion de la norme repose sur des principes différenciés selon le processus de sportification de la pratique. Le basket-ball en club se joue sur un format pérenne et un terrain normalisé, ce qui n’est pas le cas du paintball où de multiples formats de jeu sont encore d’actualité. L’escalade se situe quant à elle dans un entre-deux, sommée de sélectionner une discipline au détriment des autres en vue d’une future olympisation. L’intérêt principal de cette étude réside notamment dans le fait de rendre compte de la socialisation sportive comme inductrice de la réalisation subjective des individus. Cette socialisation s’opère par le biais du rapport à l’institution qu’entretiennent les pratiquants avec la normativité sportive. / Any sport practice is dependent upon sets of rules which simultaneously prescribe and forbid what must or mustn’t be done. These rules are codified, they contribute to the sport institutionalization specific to modern competitive sports. We’ll focus on club-organized practice. This thesis work gives an account of how game codes are passed on, of the social representations of sport’s stakeholders - players, coaches, referees and managers - as well as how its norms – game rules, space, length – are dealt with by the various organizations. Our research is based on a comparative approach between three sports that reflect different levels of institutionalization: basketball, paintball and climbing. This work concurrently builds on the use of observation – i.e. training sessions in clubs, competitions -, semi-structured interviews (n = 52) and the method of pair-wise comparisons. It shows sport rule implementation is perceived differently depending on the level of institutionalization - paintball being the least sportified among the three sports - as much as on the practice characteristics (socio-motor and psycho-motor situations). The passing on of the game’s codes is consubstantial with an actual practice culture whereas social representations can be distinguished by one’s sporting career. Also, the way norms are handled lies on differentiated guidelines depending on the practice’s sportification process. Club basketball playing is performed in a durableformat on a normalized sports ground; this is not the case of paintball for which different game formats are still being explored. As for climbing, its format falls somewhere in-between as it has had to opt in for a specific discipline rather than another with the view of an Olympic status. The particular relevancy of this study lies in the fact that it shows sport socialization can induce the individual’s subjective fulfillment. This socialization operates through the institutional prism of the link the players have with the sport’s normativity. / Toda práctica deportiva depende de un sistema de reglas que prescriben y prohíben al mismo tiempo. Estas reglas están codificadas y forman parte del marco de la institucionalización deportiva propia del deporte de competición contemporáneo. Nos interesan los deportes basados en prácticas federadas, es decir, en clubes. Esta tesis da cuenta de la transmisión de los códigos de juego, de las representaciones sociales de los actores del deporte (practicantes, entrenadores, árbitros, dirigentes) así como de la gestión de la norma deportiva (espacios, duraciones, reglas del juego) por parte de las instituciones de referencia. Nuestra investigación adopta un enfoque basado en la comparación de tres deportes que presentan un grado de institucionalización muy distinto: el baloncesto, la escalada y el paintball. Este trabajo se apoya simultáneamente en el uso de observaciones (sesiones de entrenamiento en clubes, competiciones), entrevistas semi-estructuradas (n = 52) y el método de la comparación por pares. Cabe destacar una percepción diferenciada de la aplicación de la regla deportiva, que depende tanto del nivel de institucionalización (el paintball es la menos deportivizada de las tres disciplinas) como de las características de la práctica (situaciones sociomotrices y psicomotrices). La transmisión de los códigos de juego es consustancial a una cultura activa de la práctica deportiva, mientras que las representaciones sociales se distinguen en función de la carrera deportiva. La gestión de la norma se basa en principios diferenciados que varían según el proceso de deportivización de la práctica. El baloncesto, en club, se juega en un formato perenne y en un terreno normalizado, lo cual no ocurre en el paintball, disciplina en la que varios formatos de juego permanecen en uso. La escalada se sitúa en un punto intermedio, dada la selección necesaria de una disciplina con respecto a otras de cara a un futuro reconocimiento como disciplina olímpica.El principal interés de este estudio recae en el hecho de abordar la socialización deportiva como motor de la realización subjetiva de los individuos. Esta socialización se manifiesta a través de la relación que los practicantes mantienen con la institución y con la normalización deportiva.

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With the dramatic advances that have taken place in microelectronics over the past three decades, ball-grid array (BGA) packages are increasingly being used in microsystems applications. BGA packages with area-array configuration have several advantages: smaller footprint, faster signal transmission, testability, reworkability, handling easiness, etc. Although ceramic ball grid array (CBGA) packages have been used extensively in the microsystems industry, the use of plastic ball grid array (PBGA) packages is relatively new, especially for automotive and aerospace applications where harsh thermal conditions prevail. This thesis work has developed an experimental and a theoretical modeling program to study the reliability of two PBGA packages. The physics-based theoretical models take into consideration the time-dependent creep behavior through power law creep and time-independent plastic behavior through multi-linear kinematic hardening. In addition, unified viscoplastic constitutive models are also taken into consideration. The models employ two damage-metrics, namely inelastic strain and inelastic strain energy density, to predict the solder joint fatigue life. The theoretical predictions have been validated through air-to-air in-house thermal cycling tests carried out between 55 and #61616;C and 125 and #61616;C. In addition, laser-moir interferometry has been used to determine the displacement contours in a cross-section of the package at various temperatures. These contours measured through moir interferometry have also been used to validate the thermally-induced displacement contours, predicted by the models. Excellent agreement is seen between the experimental data and the theoretical predictions. In addition to life prediction, the models have been extended to map the field-use conditions with the accelerated thermal cycling conditions. Both linear and non-linear mapping techniques have been developed employing inelastic strain and strain energy density as the damage metric. It is shown through this research that the symmetric MIL-STD accelerated thermal cycles, currently in practice in industry, have to be modified to account for the higher percentage of creep deformation experienced by the solder joints in the field-use conditions. Design guidelines have been developed for such modifications in the accelerated thermal cycles.

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