Kyoto University (京都大学) / 0048 / 新制・論文博士 / 博士(工学) / 乙第12290号 / 論工博第4006号 / 新制||工||1450(附属図書館) / 26628 / UT51-2008-T61 / (主査)教授 檜山 爲次郎, 教授 松原 誠二郎, 教授 中條 善樹 / 学位規則第4条第2項該当

High voltage direct current. (hvdc) transmission of electrical paver has been made possible with the recent advent of multi-anode mercury arc valves with grading electrodes. However, mercury are valves do suffer from random phenomena such as arcback, which requires special bracing for the converter transformer. In addition, mercury arc valves need considerable auxiliaries, including cooling and vacuum plants. Research and development directed towards the improvement in the voltage and current capabilities of thyristors are yielding encouraging results. In contrast to mercury arc valves, thyristors do not suffer from random phenomena and require minim auxiliaries. Considering these advantages, thyristors offer a viable alternative to mercury arc valves for hvdc converters. The comparatively low ratings of thyristors necessitate series and parallel connection of thyristors in order to construct a valve of sufficient rating for hvdc operation. The design of thyristor valve should ensure even distribution of voltage and current among all thyristors of the valve, during all operating conditions. To achieve this objective transmission of the firing signal to the gate of each thyristors should have good coherence. The thesis examines design aspects, and considers the different methods of firing both theoretically and practically. Finally, the design and subsequent experimental results of the prototype thyristors valve rated at 10kv and 10A are also included.

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In most African states, arable land and other natural resources play a pivotal role for economic growth and development. Ethiopia is one of those countries where agriculture is the backbone of the economy. Since the time of Emperor Haile Selassie I, Ethiopia has been attempting to advance the transformation of its agricultural sector by moving away from small-scale subsistence farming to large-scale commercial farming. It thus encouraged Foreign Direct Investment (FDI) in largescale agriculture. However, the military government that took power in 1974 reversed this. The current government of Ethiopia seized power from the military regime in 1991. Today the government once again advocates FDI in large-scale agriculture. This has led to an influx of foreign investors, especially in Gambella and Benshanguel-Gumuz Regional States. Various scholars, however, criticize the manner in which these investments have been taking place, arguing that the investments are neither pro-poor nor sustainable. Against this backdrop this research seeks to examine current policies, the patterns of investment they promote, and how these affect land-based resources and the wellbeing of communities. The study intends to provide information that may help improve the performance of FDI in terms of their sensitivity to poverty alleviation and sustainability. It also aims to boost current knowledge on FDI in agriculture in Ethiopia. The study was conducted using multiple data collection methods, including documentation, interviews, focus group discussions with the affected communities and direct observations in the case study areas. The results are analysed using pro-poor and sustainability frameworks for FDI in large-scale agriculture, along with findings of empirical studies on national FDI policies and practices in various parts of the globe. The analyses reveal that the Ethiopian investment policy's support to FDI in large-scale agriculture is inadequate. It focuses on giving incentives to attract FDI rather than ensuring the availability of quality institutions and sufficient infrastructure, which are vital for facilitating the operation and productivity of FDIs. Furthermore, the absence of community participation in the decision-making process for the agricultural investment projects in the case study areas portends significant negative implications for the wellbeing of local communities and the sustainability of the natural environment. The study recommends further research to investigate the economic viability of alternative land-based investments, such as eco-tourism, which is shown to be environmentally sustainable and can be shaped to be pro-poor. Also recommended is additional research into good practices for large-scale agricultural investments, that can be adapted to Ethiopian conditions, should the government opt to continue promoting FDI.

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<p> The products and mechanism of the photolytic rearrangement of the equilibrium mixture of triphenylmethylcyclopentadienes have been studied. Direct irradiation of the equilibrium mixture of triphenylmethylcyclopentadienes yields 5,6,6-triphenylbicyclo{3.1.0}hex-2-ene. Photolysis with a triplet sensitizer yields dimeric products in addition to 5,6,6-triphenylbicyclo{3.1.0}hex-2-ene. Thermolytic isomerization of 5,6,6-triphenylbicyclo{3.1.0}hex-2-ene is reported. The predominant isomer in the equilibrium mixture of triphenylmethylcyclopentadiene has been established as 2-triphenylmethylcyclopentadiene.</p> / Thesis / Master of Science (MSc)

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International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / As part of the National Polar-orbiting Operational Environmental Satellite System (NPOESS) Preparatory Project (NPP), the Direct Readout Laboratory (DRL) of NASA/GSFC Code 935, is developing the prototype NPP In-Situ Ground System (NISGS). The NISGS supports earth remote sensing, and its functions bridge from all EOS satellites to planning for future NASA and interagency launches. The NISGS solution enables the end user to acquire and process NPP and predecessor instrument data, and provide a means to make these technologies and data products available to the Direct Broadcast Community. This document describes the NISGS model, methodology, and system architecture.

Made available in DSpace on 2015-04-22T22:10:22Z (GMT). No. of bitstreams: 1 Helido Guedes Montenegro Filho.pdf: 2333644 bytes, checksum: 3a009dbcac0a54d285c882e1a0f92df4 (MD5) Previous issue date: 2011-06-02 / O presente trabalho é um estudo de caso no qual foi analisado um processo adotado por uma empresa no Polo Industrial de Manaus. O novo processo foi adotado em decorrência de circunstâncias especiais ocorridas junto aos fornecedores que possuem empresas no município de Manaus, e que ora realizam entregas de matérias-primas para a empresa. Foi implantado um processo que elimina a necessidade de comunicação baseado em dados manuais com os fornecedores, promovendo sincronia com a execução das linhas de manufatura, denominado de entrega direta à linha de produção (EDLP). Esta ferramenta habilitou o fornecedor entregar apenas certa quantidade de estoque necessário as ordens de produção, no momento correto da execução na linha de manufatura, evitando assim estoques desnecessários no armazém da empresa. Os fornecedores recebem os pedidos em ciclos de quatro horas, procedendo assim com suas entregas, na certeza que serão prontamente recebidos, sendo suas peças endereçadas diretamente às linhas de manufatura, para conclusão e adequação aos requisitos dos clientes finais da empresa. O método utilizado para estudar a aplicação do conceito do processo de entrega direta à linha de manufatura foi o Estudo de Caso, pois possibilitou a observação de uma realidade através de um método científico, havendo a necessidade de observar aspectos que validam o processo investigativo como, por exemplo, a confecção de um protocolo de pesquisa. Foi necessário elaborar um referencial teórico da literatura disponível sobre assuntos tais como; a Manufatura Enxuta e o uso de JIT e Kanban, a Produção Sincronizada e o uso do MRP e MRP II e no Suprimento Automático o uso de CRP e VMI. Ainda foi necessário elaborar uma pesquisa bibliográfica em assuntos como a utilização de ferramentas de tecnologia de informação (TI) na cadeia de suprimento, processos colaborativos de suprimento entre os quais se destaca o DSD (Direct Store Delivery). Os dados primários foram coletados através de aplicação de questionários individuais sobre o processo junto ao envolvidos de forma habilitar a comparação entre a teoria analisada e os fatos observados pelo público alvo da investigação. Os dados secundários foram levantados através dos procedimentos e instruções de trabalho referentes ao processo de entrega direta à linha de produção, provendo embasamento documental à pesquisa. Foram ainda analisados fluxos e mapas de processo sempre que disponíveis para consulta, tanto na empresa como nos fornecedores que atuam como parceiros. Portanto, baseado nos indícios levantados observou-se a validade das proposições retiradas da teoria. Após a análise do processo de entrega direta à linha de produção, compreende-se que este processo pode colaborar com a redução dos estoques de processo nas empresas através da promoção de um processo alinhado entre a forma como será executado o plano de produção, e a forma como os fornecedores são acionados e devem responder este chamado. Estes aspectos aliados a tecnologia da informação e um processo controlado de execução sincronizada favorecem o processo de entrega direta à linha de produção, levando a empresa a concluir que não há necessidade de manutenção de estoques intermediários desnecessários ao processo de produção realizado nas linhas de produção da empresa.