No description available.

No description available.

Thesis (Ph.D) -- McMaster University, 1997. / Includes bibliographical references (leaves129-140). Also available via World Wide Web.

Thesis--Auburn University, 2009. / Abstract. Vita. Includes bibliographical references.

Thesis (doctoral)--Helsinki University of Technology, 2006. / Includes bibliographical references. Also available on the World Wide Web.

Rotor dynamic analysis of liquid ring seals depends upon the correct specification of seal dynamic stiffness and damping characteristics. These are in turn dependent upon several parameters, including the friction holding force between the sealing face and the mating retaining ring. Designers currently assume a value for effective friction coefficient in order to utilize methods for prediction of response and stability. This thesis presents the results of testing on twelve actual seal rings of varying configuration at pressures of 689, 1378, 2068, and 2757 kPa in a static seal test rig to experimentally determine values of effective friction coefficient. The results are presented in graphical form as average effective friction coefficient versus eccentricity ratio for forward and backward motion of the rings. / Master of Science

No description available.

Nowadays sealing systems are commonly designed by means of hydrodynamic and elastohydrodynamic theories. Although the analytical as well as the computational approaches have improved in meaning full manner since the last decades: For small sealing gaps, in the order of micrometers and below, a discrepancy between experimental investigated and theoretically predicted leakage flows occur. As a cause for the discrepancy a breakdown of the no slip boundary condition is suspected. Since in small sealing gaps the continuum hypothesis is violated and molecular effects have to be considered. One fundamental quantity to take molecular affects into account is the slip length. Within this paper a new measurement apparatus to evaluate the slip length for hydraulic applications is presented. The adjustable gaps between two planar surfaces are in the order of magnitude of 1 μm. In a first step the slip length for the system steel-oil –steel is investigated at three different temperatures: 18°C, 22°C and 25°C. The measured slip lengths are in the order of magnitude of ~100 nm.

O meio corporativo, principalmente quando se trata de montadoras automotivas, é carente de conhecimento dos fatores que podem influenciar o processo de união entre pares tribológicos. Quando há um fim específico, como o tema deste trabalho: assegurar níveis de controle capazes de eliminar os riscos de uma vedação deficiente na câmara de combustão com custo mínimo, tal carência é ainda maior. O estudo da tribologia inerente à união entre cabeçote e bloco do motor diesel é fundamental para se compreender a que ponto é possível garantir a melhor estanqueidade possível, especialmente no que esteja relacionado ao processo rotineiro de aperto na linha de produção. Nesse sentido, a investigação proposta neste trabalho tem o claro objetivo de propor melhores condições técnicas de vedação ao caso particular da união entre cabeçote e bloco do motor de forma a eliminar / minimizar qualquer influência externa durante o aparafusamento do par supracitado. Adicionalmente, o conhecimento aqui exposto poderá ser difundido a muitas outras aplicações similares nas quais a fixação aparafusada está atrelada a funções que não apenas de fixação, podendo estas estarem inclusive em outros universos do produto, tais como motores, cabinas, eixos e transmissão. / The automobile corporate field has a lack of knowledge when the subject is related to tightening specific issues, especially regarding tribological studies. When there is a specific goal as this thesis theme: ensure all the control levels to eliminate sealing deficiency risks inside combustion chamber in a low investment cost, the needs are even higher. The tribological study between diesel engine block and its cylinder heads assembly is essential to comprehend what is necessary to have the best possible sealing, mostly when it\'s related to the routine on the assembly tightening process. Thinking on that, this work has the goal to propose the best condition on fastening technique that guarantees the sealing to any superficial topography roughness. Additionally, the acquired knowledge will be spread to other similar applications that are not unequally associated to bolted joints, but also in other vehicle universes, such as engines, cabs, axles and transmissions.

Na confecção de uma prótese ocular a íris artificial é a estrutura responsável pela sua dissimulação e estética. O propósito do presente trabalho foi avaliar a interação tinta e selamento utilizados na pintura da íris protética, verificando as falhas e insucessos na fase de prensagem da íris no corpo escleral. Para este estudo, foram confeccionados quatro tipos de corpos de prova sendo, dez calotas lisas utilizando cianoacrilato como selante, dez calotas lisas utilizando polímero de acetato de vinila como selante, dez calotas despolidas utilizando cianoacrilato como selante e dez calotas despolidas utilizando polímero de acetato de vinila como selante. Os corposde- prova foram submetidos a uma análise em uma lupa estereoscópica para verificação da presença de falhas, e um corpo de prova de cada grupo foi levado a um microscópio eletrônico de varredura para estudo morfológico. Nenhum corpo de prova apresentou alteração macroscopicamente, comprovando que o protocolo utilizado é eficaz podendo-se concluir que as falhas que ocorrem na confecção de próteses oculares são decorrentes de falhas em alguma fase do protocolo. Entretanto foram observados defeitos microscópicos nos grupos selados com cola de cianoacrilato. / In the manufacturing of ocular prosthesis, the artificial iris is the structure responsible for its dissimulation and esthetic. The aim of this study was to evaluate interaction between paint and sealing material used in prosthetic iris painting, attempting to failures on packing of iris shell in sclera resin. It were studied four different groups, ten smooth shells sealed with cianoacrylate, ten smooth shells sealed with vinyl acetate polymer, ten rough shells sealed with ciaoacrylate and ten rough shells sealed with cianoacrylate. Specimens were analyzed with a stereoscopic magnifying glass for detection of failures, and one specimen of each group was analyzed in a scanning electron microscope for morphological analysis. None of the specimens presented failures macroscopically, which demonstrates that the protocol employed in the present study is effective; it can be concluded that failures in manufacturing of ocular prosthesis are consequence of mistakes in one of the steps of the protocol. However, it was detected microscopic defects in specimens of the groups sealed with cianoacrylate adhesive.