Thesis(M.S.)--Auburn University, 2007. / Abstract. Vita. Includes bibliographic references.

Thesis (M.S.)--University of Wisconsin--Madison, 1982. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 83-84).

Thèse (M. A.)--Université Laval, 2008. / Bibliogr.

The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Title from PDF of title page (University of Missouri--Columbia, viewed on October 21, 2009). Thesis advisor: Dr. Hongbin Ma. Includes bibliographical references.

Issued also as the author's thesis, Zürich, 1933. / At head of title: Ouvrage publié sous les auspices du Laboratoire de Recherches Hydrauliques annexé à l'École Polytechnique Fédérale, à Zurich. "Bibliographie": p. [267]-268.

Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2005. / Includes bibliographical references (leaves 138-143). Also available in electronic version.

Recently, the rate of corrosion of copper water pipes in Bowling Green, Kentucky has unexpectedly accelerated. The specific reasons for this are unknown. Our aim is to elucidate the factors enhancing the corrosion and help understand the primary mechanisms of action. This will help in combating and reducing future corrosion incidents leading to pipe failure, thus reducing losses experienced when these pipes are replaced. This study seeks to explore the characteristics and factors involved. The scanning electron microscopy was used to obtain elemental composition, and images of both inside and outside of the corroded pipes. Strikingly, corrosion primarily occurred on the outside of the pipes, not inside. X-ray crystallography also was used to examine the pipes. The results showed that the interior of the pipes mostly consisted of SiO2, CuO2, CaCO3 while the exterior consisted of Cu2(OH)2CO3, Fe2Al2O4, CaCO3, SiO2 and Cu2O. There was no clear single factor for the corrosion observed. For further studies, we plan to long temporal experiments. The results from the study will help in minimizing the costs to the city in Bowling Green, Kentucky.

[pt] Tubulações industriais são a maneira mais segura, rápida e econômica de se transportar diferentes produtos, principalmente aqueles relacionados com a industria do petróleo. Essas tubulações sempre envolvem altos investimentos financeiros sendo, portanto, fundamental a garantia de um funcionamento contínuo, com o mínimo de interrupções. Para isso são usados Pigs. Pigs são dispositivos utilizados com muita frequência e com várias finalidades, tais como limpeza e desobstrução de tubulações, retirada de água, vedação de linhas, separação de diferentes produtos, remoção de condensado, inspeção e em testes hidrostáticos. O modelo aqui desenvolvido utiliza as equações unidimensionais da conservação de massa e da quantidade de movimento linear, para simular o movimento transiente do fluido. A equação de conservação de quantidade de movimento para o Pig é resolvida simultaneamente. Uma equação auxiliar para prever a vazão de fluido através do by-pass é proposta e acoplada ao sistema. Vários casos típicos são estudados, obtendo-se excelentes resultados. / [en] Industrial pipelines are the safest, fastes and the most economical way to transport a large range of products, mostly those related to the oil industry. Pipeline systems are usually associated with huge financial investiments, being of fundamental importance to sustain their continuous operation, and maintainning them, reducing the number of interruptions or accidents at a minimum level. To accomplish that, pigs are used. Pigs are devices frequently used for many different purposes, a few of them are clemaming and dewatering a pipeline, sealing of a papeline, transport of different products, inspection and hydraulic tests all of them being accomplished without the interruption of the production lines. The developed model uses the unidimensional conservation equation of mass and linear momentum to simulate the transient movement of the fluid. The conservation of linear momentum of the Pig is also solved, Auxiliary equation to predict the by-pass flow is also incorporated into the system. several special cases are studied with very good results.

Orientador: Tomaz Manubu Hashimoto / Banca: Marcelo dos Santos Pereira / Banca: Cristina de Carvalho Ares Elisei / Resumo: Com os novos desafios impostos pelas condições cada vez mais severas dos poços de petróleo offshore a necessidade de materiais mais modernos e com melhores propriedades mecânicas tem sido um desafio constante. Neste trabalho foi realizada a caracterização mecânica de tubos fabricados a partir de chapas de aço laminadas a quente, seguido de resfriamento acelerado. Os valores reportados são resultados de testes de laboratório aplicados em corpos de prova retirados do metal de base, de solda e da zona termicamente afetada. A utilização destes aços na fabricação de tubos soldados por processo arco-submerso em dois passes, utilizando arcos múltiplos, tem apresentado resultados de tenacidades confiáveis e superiores aos obtidos a partir de chapas laminadas pelo processo de laminação controlada sem resfriamento acelerado, principalmente em espessuras de 16 mm e superiores. Os requisitos do teste de tenacidade especificados pela norma DNV-OS -F101 aplicados em tubos fabricados de acordo com a norma API 5L, são considerados críticos. A criticidade é função dos valores mínimos a serem obtidos e também da freqüência estabelecida para ser aplicada em cada corrida de aço utilizada na produção de cada item de fabricação. Com isso nota-se uma enorme vantagem do uso dos aços com o processo de resfriamento acelerado, visto que os mesmos tiveram uma melhor homogeneidade nos resultados de limite de escoamento, com um ganho significativo no alongamento e apenas uma pequena redução no limite de resistência. O fato de usarem menores teores de carbono, também favoreceu muito a tenacidade no metal de base e ao longo da ZTA, tendo diferenças extremamente significativas de ganho no teste de impacto e CTOD / Abstract: The main of this work is the mechanical properties characterization of pipes made from steel plates produced using hot rolling with accelerated cooling. The values reported are laboratory tests results, applied on samples taken from the base metal, weld and heat affected zone. The use of these steel plates in the manufacture of pipes by submerged arc welding process using multiple arcs has shown toughness and elongation results superior to those obtained by using hot rolled steel plates without accelerated cooling, particularly in thicknesses of 16 mm and higher. The toughness test requirements specified by DNV-OS-F101 applied for pipes manufactured aiming offshore application are considered critical. The criticality is function of the minimum values required set the sampling frequency to be applied in every steel heat used in the production of each product. Because of this the use of accelerated cooling process shows a significant advantage, since it provides a better homogeneity in yield strength results, with a significant gain in elongation and only a small reduction in tensile strength. The use of smaller amounts of carbon also greatly fostered toughness in base metal and along HAZ, with significant improvement in the impact test and CTOD. Results due to these enhanced properties the use of steels with accelerated cooling technology is essential in order to face technological challenges imposed by new requirements of submarines pipelines / Mestre

Abstract This study deals with optimal design of cantilevered fluid-conveying pipes. The aim is to maximize the critical flow speed of the fluid by means of additional masses, supporting springs or dampers along the length of the pipe. The optimization problem was formulated by modelling the pipe by FEM, using Euler-Bernoulli beam elements. The locations of the additional masses, springs and dampers and the properties of these elements (mass, spring constant and damping constant) were chosen as design parameters. The maximization problem for the critical fluid flow speed was solved by the sequential quadratic programming (SQP) technique. In addition to the presentation of the optimal values obtained for the design parameters, some aspects of the sensitiveness of the systems to variations in these parameters and the robustness of the optimum designs with respect to the stability of the system are studied. Although a considerable increase in the critical flow velocity of the fluid can be achieved in the example cases studied here, a marked sensitivity of the system to the location and properties of the additional elements in the optimum designs was observed. Also, the margin with respect to stability seems to be relatively small in some of the optimum designs considered. Non-linear numerical analysis confirmed the findings of the linear analysis with respect to the sensitivity of the optimum designs to the properties of the additional elements and revealed a very rich post-critical dynamic behaviour in the optimized structures.