Melhoria das rotas de abastecimento de materiais às linhas de produção numa empresa da indústria automóvel

Dissertação de mestrado em Engenharia Industrial (área de especialização em Logística e Distribuição)A presente dissertação, desenvolvida em contexto industrial na empresa AptivPort Services em Braga, teve como principal objetivo a melhoria de processos de abastecimento de materiais nas linhas de montagem manual de componentes eletrónicos, com foco em duas secções produtivas do Edifício 1. O projeto de investigação iniciou-se através da observação dos processos de abastecimento de materiais das duas secções produtivas, identificando as rotas e tarefas efetuadas pelos colaboradores e recolhendo vários dados necessários para as fases a posteriori. Na secção de montagem manual de componentes eletrónicos (CBA+Sub-Assembly) foram desenvolvidos vários modelos de simulação no software SIMIO, retratando as diferentes combinações de produção nas linhas de montagem. Com recurso aos modelos de simulação desenvolvidos foi possível caraterizar o comportamento do sistema inicial e, face aos resultados obtidos das várias experiências, identificou-se o melhor cenário de melhoria, através da comparação das taxas de ocupação dos colaboradores e do comportamento dos materiais ao longo do tempo e da verificação da inexistência de paragens de linha. Na secção de montagem final de aparelhos (Final Assembly), decorrente de um Workshop Kaizen, foram analisados os processos e identificadas, testadas e implementadas as melhorias propostas. Estas ações consistiram essencialmente na aplicação de Standard Work aos processos de abastecimento de materiais e na criação de sinergias entre processos para melhor aproveitamento dos colaboradores, reduzindo os desperdícios identificados. Como resultado, a empresa conseguiu alcançar poupanças monetárias na ordem dos 30.000€/ano. O projeto desenvolvido constitui uma base para a melhoria contínua de todos os processos de abastecimento de materiais da organização.This dissertation was developed in an industrial context at AptivPort Services in Braga, the main objective was the improvement of material supply processes on the manual assembly lines of electronic components, focusing on two productive sections of the Building 1. The research project began by observing the material supply processes of two production sections, identifying the routes and tasks performed by the employees and collecting information needed for later phases. In the manual assembly of electronic components (CBA + Sub-Assembly) several simulation models were developed in SIMIO software, showing the different production combinations in the assembly lines. Using these simulation models developed, it was possible to characterize the behaviour of the initial system and, observing the results obtained from the various experiments, the best improvement scenario was identified by comparing employees occupancy rates and the behaviour of materials over the time and checking for no line stops. In the final assembly section, resulting from a Kaizen Workshop, processes were analysed, and the proposed improvements were identified, tested and implemented. These actions essentially consisted of applying Standard Work to the material supply processes and creating synergies for better employee use, reducing identified waste. As a result, the company was able to achieve monetary savings around 30,000 € per year. The project developed constitutes a basis for the continuous improvement of all material supply processes of the organization

Engineering of Nanostructured Carbon Catalyst Supports for the Continuous Reduction of Bromate in Drinking Water

Recent works in the development of nanostructured catalysts for bromate reduction in drinking water under hydrogen have highlighted the importance of the properties of the metallic phase support in their overall performance. Since most works in catalyst development are carried out in powder form, there is an overlooked gap in the correlation between catalyst support properties and performance in typical continuous applications such as fixed bed reactors. In this work, it is shown that the mechanical modification of commercially available carbon nanotubes, one of the most promising supports, can significantly enhance the activity of the catalytic system when tested in a stirred tank reactor, but upon transition to a fixed bed reactor, the formation of preferential pathways for the liquid flow and high pressure drops were observed. This effect could be minimized by the addition of an inert filler to increase the bed porosity; however, the improvement in catalytic performance when compared with the as-received support material was not retained. The operation of the continuous catalytic system was then optimized using a 1 wt.% Pd catalyst supported on the as-received carbon nanotubes. Effluent and hydrogen flow rates as well as catalyst loadings were systematically optimized to find an efficient set of parameters for the operation of the system, regarding its catalytic performance, capacity to treat large effluent flows, and minimization of catalyst and hydrogen requirements. Experiments carried out in the presence of distilled water as a reaction medium demonstrate that bromate can be efficiently removed from the liquid phase, whereas when using a real water matrix, a tendency for the deactivation of the catalyst over time was more apparent throughout 200 flow passages over the catalytic bed, which was mostly attributed to the competitive adsorption of inorganic matter on the catalyst active centers, or the formation of mineral deposits blocking access to the catalyst

Characterisation of microbial attack on archaeological bone

As part of an EU funded project to investigate the factors influencing bone preservation in the archaeological record, more than 250 bones from 41 archaeological sites in five countries spanning four climatic regions were studied for diagenetic alteration. Sites were selected to cover a range of environmental conditions and archaeological contexts. Microscopic and physical (mercury intrusion porosimetry) analyses of these bones revealed that the majority (68%) had suffered microbial attack. Furthermore, significant differences were found between animal and human bone in both the state of preservation and the type of microbial attack present. These differences in preservation might result from differences in early taphonomy of the bones. © 2003 Elsevier Science Ltd. All rights reserved