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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Estudo preliminar do comportamento de hidrocarbonetos policiclicos aromaticos (HPAs) em solo por isotermas de sorcao

D'AGOSTINHO, ADRIANA 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:49:43Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:01:21Z (GMT). No. of bitstreams: 1 09991.pdf: 5492615 bytes, checksum: ba479cf83ce76514f63501df3fa92374 (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
82

Um modelo baseado em metaheurística para o sequeciamento de bateladas em redes dutoviárias

Yamamoto, Lia 27 October 2009 (has links)
ANP / O scheduling operacional de uma rede de distribuição de produtos derivados do petróleo é um problema combinatório complexo, de difícil resolução computacional. Este problema pode ser decomposto em três subproblemas de acordo com os elementos chaves do scheduling: aloca- ção dos recursos, seqüenciamento das atividades, e determinação do tempo para a utilização dos recursos pelas atividades. O presente trabalho apresenta o desenvolvimento de um modelo para a solução do subproblema de seqüenciamento das atividades. O seu principal objetivo é propor uma solução baseada em metaheurística para a geração de ordenações das bateladas de produtos derivados do petróleo, criando um modelo de auxílio à tomada de decisão durante as operações de uma malha dutoviária. Da prática operacional, sabe-se que o seqüenciamento de bateladas tem grande influência no resultado final do scheduling. Além disto, a escolha da me- lhor sequencia é um problema multiobjetivo, dependente dos critérios considerados na escolha (atendimento à demanda ou à produção, ocupação dos dutos, etc.). Neste trabalho realizou-se a implementação de várias técnicas metaheurísticas para a solução do problema de seqüencia- mento. Foram analisados os resultados alcançados com o uso de diferentes funções objetivo na otimização. Os resultados mostraram um bom desempenho das metaheurísticas estudadas no seqüenciamento, o que possibilitou a obtenção de boas soluções em um curto tempo computacional. Estudou-se mais profundamente o modelo baseado em algoritmo genético que permite fornecer um conjunto de soluções que representam diferentes opções de possíveis sequencias a serem escalonadas na rede. Este modelo foi, em seguida, extendido para tratar o caso de múltiplos objetivos. Desenvolve-se então uma abordagem baseada em MOGA (Multiobjective Genetic Algorithm) que apresentou bons resultados além de uma maior diversificação de sequencias quando comparado com a solução com objetivo único. Os modelos propostos foram validados em instâncias reais da rede de dutos brasileira e constituem uma ferramenta de auxílio à tomada de decisão operacional, resultando num uso mais eficiente da malha dutoviária estudada. / The scheduling of activities to distribute oil derivate products through a pipe network is a complex combinatorial problem, that presents a difficult computational solution. This problem can be decomposed on three sub-problems according to the key elements of scheduling: assignment of resources, sequencing of activities, and determination of resource timing utilization by these activities. This work develops an approach to the sequencing sub-problem. The main objective is to develop an approach based on metaheuristic for the order generation of oil derivate products batches. The approach goals is to aid the operational decision making of the schedu- ling problem in a pipeline network. From the operational practice, the batches sequencing has great influence on the final scheduling result. Moreover the best order choice is a multiobjective problem and depends on the considered criteria (fulfillment of demand and production, pipe- line occupation rate, etc.). Some metaheuristic techniques were implemented to the sequencing problem. Results in using different objective functions on sequencing optimization were also analyzed. The metaheuristic showed a good performance in sequencing, which resulted on good solutions in a small computational time. A model based on genetic algorithm was intensively studied and it has provided a set of solutions that means different options of possible sequences to be schedule in the pipeline network. This model was also extended to treat multiple ob- jectives. A model based on MOGA (Multiobjective Genetic Algorithm) was developed and it showed good results and also good batches sequencing diversification. The proposed models were validated for real scenarios in the Brazilian pipeline network and have become a tool to aid the operational decision making, resulting in an improvement of the study of this pipeline network.
83

Uma contribuição para a inserção do gas natural como alternativa viavel na matriz energetica nacional / A contribution for the use of natural gas as an alternative in the national energetic matrix

Lourenço, Sergio Ricardo 14 July 2006 (has links)
Orientador: Elias Basile Tambourgi / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-06T18:00:35Z (GMT). No. of bitstreams: 1 Lourenco_SergioRicardo_D.pdf: 3506133 bytes, checksum: 13d45386c81ce4c3ca782d3a2fdd301e (MD5) Previous issue date: 2006 / Resumo: A utilização do gás natural tem experimentado acentuado crescimento, motivado por suas características técnicas, ambientais e econômicas, apesar de não ser um recurso renovável. O emprego deste energético traz vantagens quando comparado ao petróleo nas aplicações e em alguns processos. Dessa forma, há grande abrangência no uso do combustível no setor energético, industrial, residencial, comercial e de transporte. Durante a última década houve significativas mudanças no setor energético brasileiro, cujo preceito baseava-se no desenvolvimento de princípios sustentáveis para a sociedade, logo, o Estado vislumbrou a consolidação da tríade energética futura, composta pelo petróleo, eletricidade e gás natural. Hoje se percebe que nos últimos anos o gás natural ampliou a sua participação na matriz energética nacional, motivado pelas suas favoráveis propriedades e condições de oferta. Todavia, a situação política que permeia o setor gasífero atualmente traz apreensões sobre os fundamentos que preconizam uma política energética coerente. Neste contexto é que se desenvolve o presente trabalho, cujo objetivo precípuo é fornecer subsídios para que decisões acerca da utilização do energético possam ser tomadas com maior estabilidade e clareza. Para tanto, é investigado o desenvolvimento do setor por meio da apresentação atual da situação de reservas, produção, políticas e tendências, tanto no Brasil como ao longo do mundo. Também é discutida a aplicação econômica do energético em um caso industrial, possibilitando a melhor visualização da análise e percepção da sensibilid~de relativa à opção pelo uso do gás natural. Por fim, é plausível depreender que em um cenário menos turbulento e com preceitos mais claros, torna-se possível o melhor uso do gás, o qual facultará em benefícios para a sociedade brasileira. Contudo, na cena atual, a volatilidade da situação pode aumentar ou diminuir o risco referente à substituição energética, o que dissemina instabilidade e receio ao mercado consumidor. Porém, crê-se que tal conjunção seja inerente ao processo de desenvolução do setor e tão logo as variáveis mais sensíveis do sistema coadunem, existirá uma indústria de gás madura no país / Abstract: The use of natural gas has shown an marked growth motivated by its technical, environmental, and economical characteristics, althouglt it is not a renewable resource. To use its energy brings advantages when compared to oil in some applications and processes. Therefore, there has been a great inclusion of its use as a fuel in industrial, residential, commercial, and transport sectors. Significant changes have taken place in the Brazilian Energy Sector for the last ten years, in which its role was based on the development of sustainable principIes for the society. Brazil has seen the consolidation of future energy three-way sources, i.e., oil, electricity, and natural gas. Recently, natural gas has increased participation in the national energy matrix, motivated by its favorable properties and availability. However, the political situation that permeates this area currently brings concerns on the foundations to create an assured energy policy. The present paper is developed in this context, in which its main aim is to supply subsidies so that decisions on the use of energy can be made with both higher stability and transparency. This way, the development of its sector is investigated by means of the current presentation of gas natural resources, production, policy, and' trends, in Brazil and around the globe. It is also discussed the economic application of this gas in an industrial plant, making possible the best visualization of the analysis and the perception of its relative sensitivity. FiÍlaIly, it is reasonable to infer that ha a less turbulent scene and with clearer mIes, it is possible to achieve a better use for this gas, which wiIl give benefits for the Brazilian society. However, in the curr~nt scene, the volatile situation may increase or decrease the risk to its replacement, which spreads instability and doubts in the market. It is believed that such view is inherent to the process oí development and as soon as the variables find their right values, there wiIl be a more mature industry in our country / Doutorado / Sistemas de Processos Quimicos e Informatica / Doutor em Engenharia Química
84

Estudo preliminar do comportamento de hidrocarbonetos policiclicos aromaticos (HPAs) em solo por isotermas de sorcao

D'AGOSTINHO, ADRIANA 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:49:43Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:01:21Z (GMT). No. of bitstreams: 1 09991.pdf: 5492615 bytes, checksum: ba479cf83ce76514f63501df3fa92374 (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
85

Avaliação dos problemas ambientais relacionados aos aspectos geológico-geotécnicos e dutos enterrados, poliduto Osbra: trecho Porto Ferreira - Ribeirão Preto / Evaluation of environmental problems related to the geological-geotechnical aspects and buried pipeline, pipeline OSBRA: link Porto Ferreira and Ribeirão Preto

Joseli Ferreira 27 July 1999 (has links)
Vazamentos decorrentes de acidentes envolvendo dutos constituem uma fonte potencial de contaminação das águas subsuperficiais, superficiais e dos componentes dos meios físico e biológico, em geral. Neste trabalho são analisados os problemas ambientais decorrentes de possíveis vazamentos dos produtos transportados no poliduto OSBRA, no trecho situado entre Porto Ferreira e Ribeirão Preto (SP). Este trecho está localizado em uma área de intensa ocupação agrícola, atravessando extensa área de recarga da Formação Botucatu e de basaltos fraturados pertencentes à Formação Serra Geral, além de vários canais de drenagem. Todas estas áreas estão, portanto, sujeitas à contaminação em caso de acidentes envolvendo o duto. Neste trabalho são apontados os principais agentes deflagadores de possíveis acidentes no trecho e analisados os diferentes contextos de contaminação de acordo com as características do meio físico e do produto liberado. / Leakage from pipeline constitute a potential source of groundwater and surface water contamination as well as to geological and biological environment components. In this research the environmental problems due to leaking of petroleum products transported by OSBRA pipeline, which runs between Porto Ferreira and Ribeirão Preto (SP), are analyzed. It is located in an area of intense agricultural management, crossing large and recharge area of Botucatu Formation and fractured basaltic rocks from Serra Geral Formation. All these areas are, therefore, subject to the contamination in case of accidents involving the pipeline. The aim of this research is to analyze the agents responsible by the accidents and to determine the different types of contamination according to the main characteristic of the environment and spill material.
86

Etude des phénomènes de complexation des métaux en milieu organique et caractérisation de ces complexes par spectrométrie de masse / Study of metal complexation phenomena in organic medium and characterization of these complexes by mass spectometry

Perret, Cécile 09 July 2015 (has links)
La présence de contaminants métalliques dans les produits pétroliers engendre des effets indésirables, comme la dégradation de leur stabilité au stockage. Pour limiter ces perturbations, des additifs sont incorporés aux produits pétroliers dans le but de complexer les cations métalliques en solution. Le sujet de la thèse porte sur le développement d’une méthodologie pour étudier les interactions non covalentes dans une matrice hydrocarburée par spectrométrie de masse électrospray (ESI-MS). Plusieurs approches ont été utilisées pour comparer le pouvoir complexant de différentes molécules vis-à-vis des métaux ciblés, puis identifier les structures chimiques les plus efficaces pour inhiber l’action catalytique des contaminants. Ces travaux mettent en évidence l’apport de l’ESI-MS comme outil de présélection d’additifs, moins coûteux et chronophage que les méthodes actuelles de screening. / The contamination of petroleum products by metallic compounds leads to adverse effects, as the degradation of their stability under storage. To prevent these phenomena, specific molecules are added to petroleum products in order to complex metallic cations in solution. This work focus on the development of an electrospray mass spectrometry (ESI-MS) method to study non covalent interactions in a hydrocarbon medium. Several approaches were employed to compare the complexing ability of different molecules towards targeted metals, then to identify the most efficient chemical structures to inhibit the catalytic action of contaminants. Results highlight the contribution of ESI-MS as a screening tool, less expensive and time-consuming than the methods currently used.
87

Adapting retail business models for the petroleum industry

Tait, Hennie Leon January 2009 (has links)
Deregulation as an open market system is likely to be implemented in the Petroleum industry of South Africa. To secure the success of the retail petroleum industry by means of business and job opportunities one has to investigate the current evolution of the industry and what factors will have a measurable impact on the retail petroleum industry.
88

Market Timing, Forecast Ability and Information Flow in Petroleum Futures Markets

Buchanan, William K. 12 1900 (has links)
Three petroleum futures contracts are examined over a ten-year period from 1986 to 1996. Intertemporal changes in futures prices and the net open interest positions of three trader types are compared to determine what, if any, market timing ability the traders have. Seasonal variation is considered and a simple trading rule is adopted to determine the dollar-return potential for market participation and shed light on issues of market efficiency.
89

Development of a Pre-Impact Environmental Site Characterization for the Bryan Mound, Texas Strategic Petroleum Reserve

Hernandez, Sylvia A. 12 1900 (has links)
This thesis presents a model for developing site-specific contingency plans to be used during spill response, remediation, and post-spill monitoring using the Strategic Petroleum Reserve's Bryan Mound site as a case study. Bird and vegetation observations provide baseline data for biological conditions, and sediment sampling for total petroleum hydrocarbons serves as a chemical component of the model. Results demonstrate previously unknown conditions that would hinder remediation and affect the persistence of petroleum contaminants. Results also established previously unmapped dominant bird and vegetation types likely to be impacted by a spill at the site. This model points to a reconsideration of individual facilities' responsibilities when planning for large-scale disasters and protecting the sensitive ecosystems surrounding their sites.
90

Petroleum futures trading and price volatility

Planting, Ronald James January 1986 (has links)
This study investigates the effects of futures trading on petroleum price variability. Though a number of critics from various quarters claim futures markets have made petroleum prices more volatile, economic reasoning does not support this viewpoint. A review of theoretical studies and empirical investigations of other commodities shows general support for the hypothesis that futures markets do not destabilize prices and may, in fact, add to price stability. In this study, regression analysis is used to explain the price variability of heating oil and gasoline in terms of factors that may affect this variability, including the existence of futures markets. Though the empirical tests performed are biased towards finding destabilizing effects of futures markets, no statistically significant increase in price volatility is found, and in the case of gasoline, indications of stabilizing effects are found. Thus, neither the results of other studies of futures markets nor examination of petroleum futures trading support the critics' contention that futures trading has destabilized petroleum prices. / M.A.

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