This research examines the impact of purchasing constraints and demand variability on working capital balances. The working capital accounts considered are creditors, debtors and raw material inventories. Purchasing constraints and demand uncertainty are defined. The supply chain of the South African cable industry, and one manufacturer in particular, and the challenges faced in the cable manufacturing process are discussed. To quantify the influences, a comparison between working capital accounts in the case of economic order quantity and actual purchasing practices is performed. A simulation model is developed to reproduce a larger sample of demand data, matching the cumulative probability density function of each cable type contained in the annual sales budget. The results show, that the working capital accounts react differently to changes in purchasing conditions and variations in demand, the most sensitive being raw material inventories. The study quantifies the influence of purchasing constraints on each working capital value. / Business Management / M.Com. (Business Management)

A construção de linhas de transmissão são obras de grande impacto ambiental e requerem grandes investimentos financeiros. Este projeto de pesquisa, visa por meio de ensaios de laboratório, conceber uma ferramenta sistêmica para o aperfeiçoamento do método de determinação da fluência em cabos condutores de energia e OPGW (Optical Ground Wire), que tem sido utilizada no Brasil durante os últimos 30 anos, e analisar os efeitos na construção das linhas aéreas de transmissão. Visa também, proporcionar ganhos de confiabilidade ao sistema de transmissão de energia elétrica, pois o projeto, a construção, a operação e a manutenção de linhas de transmissão dependem de parâmetros de desempenho mecânico dos condutores. Conclui–se que a metodologia de ensaio proposta proporciona resultados finais mais confiáveis quando comparado com o atual procedimento normatizado, utilizado no Brasil, e sua utilização em projetos de linhas aéreas de transmissão de energia podem reduzir custos de construção, aumentar a ampacidade das linhas já existentes, bem como, diminuir os riscos ao a que pessoas estão sujeitas quando expostas a campos elétricos e eletromagnéticos gerados por linhas de transmissão. / Overhead Transmission Line construction projects have a great environmental impact and require a large financial investment. This research aims, through laboratory tests, to improve the method of determining the creep of power cables and OPGW (Optical Ground Wire) that has been utilized in Brazil for the last thirty years, as well as analyze the effects on the construction of overhead transmission lines. It will provide greater reliability to the overhead transmission line system, since the design, construction, operation and maintenance of transmission lines depend on the mechanical performance of the conductors. In conclusion, the proposed methodology provides more reliable final results compared to the current standardized procedure and its use in overhead transmission line projects could reduce construction costs, increase the ampacity, as well as reduce the risks to which people are subject when exposed to electric and electromagnetic fields generated by power lines.

This Diploma thesis is aimed at various ways of connecting electrical parts in car locks. This part of the thesis includes technologies of electric cables, printed circuit boards, lead frames, 3D-MID technology and technology of electroconductive plastics materials. Listed technologies are compared. The aim of the practical thesis portion is the application of electroconductive plastic materials on the given part. For this purpose necessary changes were designed in the provided small series injection mold. The thesis also includes drawing documentation of the designed construction changes in the injection mold, as well as economic appraisal of the prototype manufacturing fees.

A ocorrência de arborescências em água (water tree) ou elétrica (electrical tree) é apontada como o principal fenômeno de degradação em isolações sólidas de cabos de distribuição de energia elétrica. A evolução destas arborescências pode levar a camada de isolação à ruptura dielétrica e, como conseqüência, à falha destes equipamentos, com a interrupção do fornecimento de energia elétrica. O entendimento deste fenômeno é necessário para desenvolver métodos de análise e prevenção da ruptura de materiais isolantes. Este trabalho mostra a aplicação da técnica contraste de fase por raios X como metodologia para o estudo das arborescências formadas em materiais isolantes de borracha de propileno etileno (EPR) e polietileno reticulado (XLPE). / The water tree or electrical tree occurrence is identified as the main phenomena in the degradation in solid isolations of the electric energy distribution cables. The water tree evolution can lead to dielectric breakdown of the isolation layer and, consequently, to the failure this equipment and the interruption of the electric energy supply. The understanding this phenomenon is necessary for the development analysis methods and to prevent collapse in the polymeric insulation. This work demonstrates the application of X-ray phase contrast technique as a methodology for the study of the water tree and electrical tree in Ethylene propylene rubber (EPR) and crosslinked polyethylene (XLPE).