Thesis (M. Soc. Sc.)--University of Hong Kong, 2000. / Includes bibliographical references.

Thesis (Ph. D.)--Oregon Graduate Center, 1986.

Thesis (Ph. D.)--Uppsala University, 1986. / Includes bibliographical references (p. 175-183).

published_or_final_version / Sociology / Master / Master of Social Sciences

Orientador: Amauri Garcia / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-07-23T00:16:48Z (GMT). No. of bitstreams: 1 Paula_MarcoAntoniode_M.pdf: 6257043 bytes, checksum: 67fa65ec75efb5c07d163b22b9b530c2 (MD5) Previous issue date: 1997 / Resumo: Este trabalho objetiva, essencialmente, analisar de formas teórica e experimental os aspectos relativos à purificação do telúrio, utilizando o método da fusão zonal.Processaram-se amostras de telúrio, partindo de matérias primas com pureza de 99,95 % , com 9 (nove) passadas de três zonas líquidas simultâneas, de 70 mm de largura cada uma, a uma velocidade constante de 5mm/h, em uma barra de 200 mm de comprimento. Para a caracterização do material processado foram feitas análises da composição química do material e comparadas com as do material de partida, juntamente com análises macro e micrográfica e medidas de dureza sob carga reduzida, para verificação do grau de pureza do material. Os resultados demonstraram a eficiência do processo e pela presença silmutânea de impurezas de k<1 e de k>1 há a necessidade de utilização de uma dupla fusão zonal para alcançar-se elevadas purezas / Abstract: The present work is a theoretical and practical analysis related to the tellurium purification by zone melting. The starting material was 99,95 % purity Te. The zone melting process was carried out by using three simultaneous liquid zones with 70 mmwide each one and a constant displacement speed of 5mm/h in a 200 mm long rodo Chemical analysis was performed to compare with the starting material.Both macro and micrographic analysisand also hardness testing were conducted to verify the final degree of purity. The obtained results have demonstrated the efficiencyof the processoThe simultaneous presence of k < 1 and k > 1 impurities suggests the need of using a double zone melting system to reach purity levels higher than 99.99 / Mestrado / Materiais e Processos de Fabricação / Mestre em Engenharia Mecânica

El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / In Peru, companies within the textile sector encounter problems such as a decrease in the contribution to an industrial gross domestic product from 10.6 to 7.5%, a decline in financial credits by about 0.7% p.a., and the direct competition of Central American countries across the textile chain. The finishing of fabrics shows the worst performance, with losses of a 38.8% variation in industrial production and a 7.5% growth rate per textile industrial sector. In this scenario, a strategic lean procurement model based on 5S and supplier approval was designed. The lean objective is to streamline workflow in the raw material warehouse that generates excessive lead time to production and leads to unplanned downtime. In addition, supplier approval boosts procurement efficiency and provides strategic value in assessing and planning raw materials to ensure efficient supply. The model is validated through a case study involving a textile small and medium-sized enterprise (SME), and drastic improvements are made. These improvements address the problem of unplanned downtime by reducing its incidence and making economic contributions to the company. / Revisión por pares