Thesis (Ph.D.)--Tufts University, 2000. / Adviser: Charalabos Doumanidis. Submitted to the Dept. of Mechanical Engineering. Includes bibliographical references (leaves 118-124). Access restricted to members of the Tufts University community. Also available via the World Wide Web;

Thesis (MTech (Mechanical Engineering))--Peninsula Technikon, 1999. / Word processed copy. Summary in English. Includes bibliographical references (leaves 66-68). Also available online.

Thesis (PhD (Metallurgical Engineering))--University of South Australia, 1997

Thesis (PhD (Metallurgical Engineering))--University of South Australia, 1997

Thesis (MTech (Mechanical Engineering))--Peninsula Technikon, 1999 / The simulation of Plasma Arc Cutting is presented in this study. The plasma arc cutting process employs a plasma torch with a very narrow bore to produce a transferred arc to the workpiece. A technique for modelling plasma arc cutting has been developed by applying the thermo-metallurgical model to the process and integrating a model of material removal to this model. The model is solved using the finite element method using the FE package SYSWORLD, more specifically SYSWELD. The objective is to determine the minimum energy required to cut a plate of some thickness using this virtual model. The characteristics of the cut need to exhibit the characteristics of a "high quality cut". The model presented can predict the kerf size given certain process variable settings. The numerical results obtained are assessed by conducting experiments. By maintaining Ill1rumum energy input cost savings can be made through energy savings, limiting additional finishing processes and reducing expense of shortening the electrode and nozzle lifetimes. The modelling of the PAC process using virtual design techniques provides a cost-effective solution to the manufacturing industries with respect to process specification development. This plays an important role in South Africa's transition into a competitive global market. It is envisaged that the model will provide an alternative more efficient, non-destructive means of determining the optimum process variable settings for the plasma arc cutting process.

No description available.

Thesis (Ph. D.)--University of Alberta, 2010. / Title from pdf file main screen (viewed on July 8, 2010). A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Materials Engineering, Department of Chemical and Materials Engineering, University of Alberta. Includes bibliographical references.

The Quasi-Keyhole plasma arc welding (PAW) process is a relatively simple concept, which provides a basis for controlling the weld quality of a subject work piece by cycling the arc current between a static base and variable peak level. Since the weld quality is directly related to the degree of penetration and amount of heat that is generated and maintained in the system, the Non-Linear Interval Control Algorithm provides a methodology for maintaining these parameters within acceptable limits by controlling the arc current based upon measured peak current times. The Texas Instruments TMS320VC5416 DSK working in conjunction with Signalwares AED-109 Data Converter provides a hardware solution to implement this control algorithm. This study outlines this configuration process and demonstrates its validity.

Made available in DSpace on 2014-10-09T12:52:26Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:02:36Z (GMT). No. of bitstreams: 0 / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Made available in DSpace on 2014-10-09T12:52:26Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:02:36Z (GMT). No. of bitstreams: 0 / O câncer de próstata é um problema de saúde pública no Brasil, sendo a segunda causa de óbitos por câncer em homens, superado apenas pelo câncer de pulmão. Entre os possíveis tratamentos disponíveis para o câncer de próstata encontra-se a braquiterapia, onde, pequenas sementes contendo o radioisótopo 125I são implantadas na próstata. A semente consiste de uma cápsula de titânio selada de 0,8 mm de diâmetro externo e 4,5 mm de comprimento, contendo um fio de prata com 125I adsorvido. A soldagem por arco plasma é uma das técnicas viáveis para selagem, o equipamento tem um custo menor que o de outros processos. Constituem os objetivos deste trabalho o desenvolvimento e a validação do procedimento de selagem utilizando processo de soldagem plasma e a elaboração de rotinas para selagem segundo as Boas Práticas de Fabricação. O desenvolvimento do trabalho apresentou as seguintes fases: corte e limpeza do material, determinação dos parâmetros de soldagem, desenvolvimento de dispositivos para fixação do tubo de titânio durante o processo de soldagem, ensaios de validação de fontes seladas conforme norma ISO 2919 Sealed Radioactive Sources General Requirements and Classification, ensaios de estanqueidade conforme norma ISO 9978 Sealed Radioactive Sources Leakage Test Methods e ensaio metalográfico. O procedimento desenvolvido para a selagem das sementes de 125I mostrou-se eficiente, atendendo a todos os requisitos estabelecidos na norma ISO 2919. Os resultados apresentados neste trabalho possibilitaram a elaboração de rotinas de fabricação segundo as orientações apresentadas na resolução RDC nº 59 Boas Práticas de Fabricação de Produtos Médicos da ANVISA - Agência Nacional de Vigilância Sanitária. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP