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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.
301

Energy profile of the Republic of Azerbaijan: recent developments and their impact on the European Union's energy security

Hajiyev, Shahmar January 2012 (has links)
This thesis will focus on Azerbaijan's oil and gas industry; how the country uses its energy revenues within its economy; how it avoids economic pathologies such as the "Dutch Disease"; Azerbaijan's role within the Caspian Basin, and finally, the European Union's energy security and how Azerbaijan's energy resources can impact it. The Republic of Azerbaijan is a natural resource-rich country, and uses its energy resources as a means of socio-economic advancement and stability. Recent developments within the country's natural gas sector have allowed Azerbaijan to become a net gas exporter. The EU's growing demand for energy resources illustrates how important it is for states to have access to secure, stable, and diverse sources of energy. Energy resource exploration and the subsequent export of these products to international markets play a crucial role for the Republic of Azerbaijan's economy. Therefore, this thesis will first provide a brief evaluation of the history of Azerbaijan's energy sector; an overview of the current situation and recent developments; and explore how energy revenues are being distributed in the economy. It will define the interests of other important actors such as Russia, Turkey and the USA; and finally, it will assess the EU energy security, the role of Azerbaijan as the...
302

Desenvolvimento de procedimentos para avaliação de curvas J-R em espécimes à fratura SE(T) utilizando o método de flexibilidade. / Estimation procedure of J-R Curves for SE(T) fracture specimens based upon the unloading compliance methodology.

Cravero, Sebastian 26 November 2007 (has links)
Este trabalho apresenta o desenvolvimento de procedimentos para a medição de curvas de resistência J-R em espécimes SE(T) usando os métodos de flexibilidade elástica e método n. Uma descrição da metodologia sobre a qual J e o crescimento de trinca são medidos estabelece o contexto para determinar dados de resistência ao rasgamento dúctil com o emprego de curvas carga vs. deslocamento obtidas experimentalmente. A extensiva matriz de análises em estado plano de deformações de espécimes SE(T) complementada, em algumas geometrias selecionadas, com análises 3D permite a determinação numérica da flexibilidade adimensional, u, e fatores nJ e Y para uma grande faixa de proporções geométricas e propriedades de material características de aços estruturais e para dutos. Ensaios laboratoriais de um aço API 5L X60 à temperatura ambiente usando espécimes SE(T) carregados por pinos com entalhes laterais (side-grooves) fornecem os dados de carga e deslocamento necessários para validar o procedimento para determinar curvas de resistência do material. Os resultados apresentados nesta tese fornecem uma base de soluções para o futuro estabelecimento de norma padronizada para a medição experimental de curvas J-R em corpos de prova SE(T) mecanicamente similares a dutos com defeitos bidimensionais. / This work provides an estimation procedure to determine J-resistance curves for pinloaded and clamped SE(T) fracture specimens using the unloading compliance technique and the n-method. A summary of the methodology upon which J and crack extension are derived sets the necessary framework to determine crack resistance data from the measured load vs. displacement curves. The extensive plane-strain analyses and key 3D results enable numerical estimates of the nondimensional compliance, u , and parameters n and Y for a wide range of specimen geometries and material properties characteristic of structural and pipeline steels. Laboratory testings of an API 5L X60 steel at room temperature using pin-loaded SE(T) specimens with side-grooves provide the load-displacement data needed to validate the estimation procedure for measuring the crack growth resistance curve for the material. The results presented in the this thesis produce a representative set of solutions which lend further support to develop standard test procedures for constraint-designed SE(T) specimens applicable in measurements of crack growth resistance for pipelines.
303

Análise elastoplástica do colapso de elementos tubulares. / Elastoplastic analysis of tubular elements collapse.

Sandoval Rodríguez, Miguel Jaime 25 August 2005 (has links)
Este trabalho objetiva o estudo específico, teórico e numérico, da determinação dos diferentes modos de colapso, elásticos e elastoplásticos, de uma estrutura tubular sujeita a esforços: pressão externa, flexão e flexo-pressurização. Entre os mais importantes elementos estruturais básicos, analisaremos inicialmente o modelo de um anel comprimido por uma carga radial. Isso significa determinar as pressões de instabilidade, elástica e elastoplástica, e de colapso, com os correspondentes modos, para anéis com diferentes relações diâmetro-espessura, D/t , submetidos a uma série gradual de pressões externas. A Estabilidade estrutural é computada utilizando uma formulação variacional, com discretização por elementos finitos. O modelo material pressupõe comportamento elastoplástico, com pequenas deformações. A análise não linear envolve a aplicação de pressurização externa aos anéis, de forma incremental, para a obtenção da resposta, tomando em conta a falta de circularidade inicial dos mesmos. Casos específicos envolvendo anéis de paredes finas e grossas serão considerados. Será analisado depois o estudo da resposta e da estabilidade de tubos de metal de parede fina e relativamente grossa sob flexão e flexo-pressurização através do método dos elementos finitos. Durante as últimas décadas este problema tem muito sido estudado através de métodos analíticos e experimentais. A maioria das soluções, entretanto, referem-se ao comportamento destas estruturas sob condições elásticas. No entanto, uma experiência de um elemento tubular é um problema inerentemente não linear com flambagem ou colapso do cilindro tomando lugar. Ás vezes com localização. Confrontaremos no final principalmente os resultados numéricos com aqueles da literatura, Kyriakides et al (1987), (1991) e (1992). / This work looks first at the determination of instability pressures as well as elastoplastic collapse, with the corresponding modes of rings with different diameter/thickness ratios under incremental external pressure loading and . Structural stability is computed by a variational formulation with discretization by finite elements. Material modeling considers elastoplastic behaviour with small deformations. Non Linear analysis produces the response curves considering lack of initial out-of-roundness. .After the response and stability of long and relatively thick wall metal tubes under bending and combined bending and external pressure were studied through experimental and analytical methods during the last decades. Most of the solutions, however, refered to the behavior under elastic conditions. In these cases we used the Finite Element Method with several discretizations. Nonetheless these experiments of a tube element is an inherently nonlinear problem with cylinder buckling or collapse taking place. Sometimes with localization. At the end numerical results are mainly compared to experimental measurements of Kyriakides et al (1987), (1991) e (1992).
304

Soldagem dos aços inoxidáveis superduplex UNS S32750 e UNS S32760. / UNS S32750 and UNS S32760 superduplex stainless steel welding.

Candel, Estevan Helio Panisello 21 March 2016 (has links)
O objetivo deste trabalho é viabilizar o uso conjunto, em um mesmo sistema de tubulação, na indústria de óleo e gás, dos aços inoxidáveis superduplex UNS S32750 e UNS S32760. Atualmente as especificações de projeto limitam o uso de um ou outro para um dado sistema, implicando em menor flexibilidade de fornecimento e maiores custos. Adicionalmente será avaliado o processo de soldagem automatizado com arame tubular com matriz metálica (metal cored) e com proteção gasosa. Este processo de soldagem possui grande produtividade e rendimento. Foram estudadas a resistência à corrosão, a resistência mecânica e possíveis danos causados à microestrutura do metal de solda e das zonas afetadas pelo calor (ZAC) dos aços inoxidáveis superduplex UNS S32750 e UNS S32760. A junta foi realizada com chanfro em meio \"V\", com geometria de 300 mm por 200 mm por 6,35 mm e com os seguintes parâmetros de soldagem: tensão de 25 V, corrente de 150 A, velocidade de soldagem de 6,35 mm/s, velocidade de alimentação do arame de 135 mm/s e distância de trabalho de 20 mm. As juntas foram caracterizadas por microscopia óptica, eletrônica de varredura, ensaio de tração, ensaio de dobramento, ensaio Charpy V a - 46 °C e ensaio de corrosão segundo a norma ASTM G48. A base para os critérios de aprovação será o disposto normativo da Norsok Standard M-601, Welding and inspection of piping, na sua mais recente edição (2008). Os resultados mostraram que não existem diferenças significativas entre as soldagens similares e dissimilares com relação às propriedades testadas. / The objective of this work is to enable the use in the same piping system, used in the oil and gas industry, of UNS S32750 and UNS S32760 superduplex stainless steels. Currently, the design specifications limit the use of one or the other for a given system, resulting in less flexibility in supply and higher costs. Additionally, it will be evaluated automated welding process with metal cored using a shielding gas. This welding process has high productivity and efficiency. It was studied corrosion resistance, mechanical strength and possible damage to the weld metal microstructure and heat affected zones (HAZ) of stainless steels superduplex UNS S32750 and UNS S32760. The joint was welded using a half \"V\" bevel geometry, with 300 mm by 200 mm by 6.35 mm and the following welding parameters: voltage 25 V, current 150 A, welding speed of 6.35 mm/s, wire feed speed of 135 mm/s and 20 mm working distance. The joints were characterized by optical microscopy, scanning electron microscopy, tensile test, bending test, Charpy V test at - 46 °C and corrosion test according to ASTM G48. The basis for the criteria for approval is the normative provisions of Norsok Standard M-601, Welding and inspection of piping in its latest edition (2008). The results showed that there are no significant differences between similar and dissimilar welds with respect to the tested properties.
305

Méthode de conception de multimatériaux à architecture multicouche : application à la conception d’une canalisation sous-marine

Giaccobi, Stéphane 16 July 2009 (has links)
Les méthodes de sélection de matériaux monolithiques peuvent conduire à des impasses lorsque les exigences fonctionnelles sont très élevées ou contradictoires. Le passage aux multimatériaux peut alors être envisagé. L’objectif de la thèse est de proposer une méthode de conception de multimatériaux à architecture fixée, avec en perspective une application à la conception de conduites offshore pour le génie pétrolier. Seuls les multimatériaux à architecture multicouche sont considérés et la méthode de conception est redéfinie comme une méthode de sélection des constituants du multimatériau et de dimensionnement. Une adaptation des étapes classiques de sélection des matériaux conduit à présenter la méthode en détail sur des exemples simples. Les techniques de programmation par satisfaction de contraintes s’avèrent nécessaires pour la résolution de cas réels de conception multimatériaux. L’application à la conception de conduites offshore permet de valider la méthode et de démontrer sa pertinence. / When the design requirements are either too stringent or are conflicting, no monolithic material solution exists. In such cases the selection of a multimaterial could be considered. The primary aim of this thesis is to provide a methodology for designing multi-materials with a prescribed arrangement of the constituent materials. The second objective is to apply this new methodology to the design of a submarine pipeline. From amongst the huge variety of multi-material arrangements available, this study focusses on multilayered stackings and therefore the design methodology becomes a method for selecting the materials of the stack and sizing the layers. This original approach is presented in detail using basic examples in order to match the steps of classical methods for selecting engineering materials. The constraints programming techniques were very useful for solving real multimaterial design problems. Applying this new method to the design of a submarine pipeline permits its validation and provides proof of its relevance.
306

Managing Exposure to Pipeline’s Risks: Improving Brazil’s Risk-Based Regulatory Process

Naime, Andre 21 June 2010 (has links)
Traditional risk-based decision-making processes have limitations that often compromise the management of technological hazards. The research is organized into three major components. Firstly, it investigates concepts and thinking outside the literature on risk regulation that offer opportunities to improve risk-based processes, such as governance and risk governance, environmental and social justice, vulnerability, resilience, complex systems, ethics, and the precautionary principle. Secondly, identified opportunities to improve risk-based approaches are assessed in the context of the Brazilian environmental licensing process for gas and oil transmission pipelines. The Brazilian case study is explored through interviews and surveys with thirty-two key stakeholders, aimed at describing and understanding the situation. Finally, it is discussed how the implications of the proposed conceptual framework and findings from the case study contribute to the theoretical perspectives on technological risk regulation. The research advocates that (1) regulatory processes for technological hazards need to effectively incorporate ‘human systems’ into their routines as a way to become more holistic; (2) decision-making processes need to strengthen the transition from assessment of risks to management of exposure; (3) regulators need to shift focus to the management of exposure as opposed to the current facility-centered management of risks; (4) this transition is facilitated if the regulatory process has an independent routine for management; and (5) a resilience plan, encompassing components from risk management and land-use planning, articulates the interaction between people and hazardous facilities, that share a common space, towards better practices to effectively manage exposure to risks. Considering these five points, the research suggests an adaptation of the Risk Governance Model for the regulation of hazardous linear installations.
307

The Guided Wave Inspection of Buried Pipe

Yeh, Chan-Chia 02 September 2012 (has links)
Abstract In a petrochemical plant, to exert economic efficiency and spacing convenience for transporting fluid or gas, the pipelines used in the plant are often buried along the road. The buried pipelines are usually wrapped in the soil that only the guided wave method is a convenient technique to perform the nondestructive testing for the pipelines. However, the viscosity of soil causes the attenuation of the guided wave during the test, the accuracy and the detection distance will then be affected. Thus, the objectives of this thesis are to study the characteristics, such as the detection distance and the refraction signal, of the T(0,1) guided wave when propagating along pipelines wrapped in the soil at different depths. The thesis would be divided into two parts: experiment and numerical simulation. Four different depths, 0.5, 1.0, 1.5 and 2.0 m, are used in the experiment to evaluate the characteristics of reflected signals and its attenuation. Wavelet transform, which would enhance the capability of distinguishing guided wave defect, is used to improve the attenuation of defected refraction signal caused by soil. In the numerical simulation, this research applies the transient simulation by finite element method to analyze the wave propagation behavior of T(0,1) mode guided wave of buried pipeline, which is incorporated with Two-dimensional Fourier transform for modal identification. The result of experiment shows that the attenuation of the guided wave is caused by the leakage and the viscosity of the soil. The decay rate is proportional to the depth and due to the viscosity of the soil is proportional to the excitation frequency. This phenomenon is more obvious when the pipeline is buried deeper. The reflected signal amplitude of each characteristic would decrease along with the increasing soil depth, but the overall trends did not changed. The result of wavelet transform shows that the capability of distinguishing of the guided wave detection defect of buried pipeline, which attenuation of refraction signal caused by soil would be improved. The result of the numerical simulation indicates that the T(0,1) mode would not cause mode conversion and dispersion due to its propagation through the buried pipeline with different depths of soil. The soil caused leakage of the T(0,1) mode in the form of shear waves. The attenuation rate of guided wave and its detection distance in the study could be the reference of site selection for detection and defect refraction signal determination, which could effectively raise the efficiency of on-site detection.
308

The Evolution Of Central Eurasia Policy Of The Us In The Post-soviet Era And The Geopolitics Of The Caspian Oil

Deger, Deniz 01 September 2006 (has links) (PDF)
The objective of this thesis is to analyze the US Central Eurasia Policy in the period between 1991 and 2006. Within this context, the purpose is to figure out the foremost motive behind the US&rsquo / s strategic engagement in the region with a due regard to changing geopolitical context with the demise of the Soviet Union. The main argument rests upon the assumption that the US regional policy is primarily motivated by geopolitical imperatives as the Central Eurasian region becomes the primary springboard for the attainment of global supremacy. Within this respect, energy is only one aspect of the ongoing geopolitical competition. That the geopolitical priorities are preponderant to geoeconomic interests are basically observed by the intense geostrategic struggle over dominating the prospective oil and gas pipelines from the region. Eventually, within the confines of this thesis, it is deduced that the ultimate parameters of the geopolitical struggle, the framework of which was specified by the United States, have revealed themselves more explicitly in the aftermath of the September 11, which only reinforced the strategic significance of Central Eurasia in coping with the new geopolitical fault lines of the 21st century. Within this regard, Central Eurasia has transformed into an implicit geostrategic standoff between the United States on the one hand, and Russia and China on the other. Accordingly, the fact that the United States could by no means remain complacent about the fate of Central Eurasia against such a backdrop of high geopolitical fluidity in the overall Eurasian continent is most relevant to the possibility of rising potential aspirants for global dominance that would challenge the United States in the long term.
309

Disjointed connections : the presidential permitting of tar sands oil pipelines at the U.S.-Canadian border

Tomasovic, Brian Scott 14 February 2011 (has links)
The fuel for dynamic change in the United State’s energy relationship with Canada lies in immense deposits of tar sands beneath the boreal forests of Alberta province. Unconventional production of oil from this resource has accelerated in recent years and remains poised for continued expansion, facilitated, in part, by plans to import tar sands crude through new pipelines to refineries in the United States. However, the development of this resource carries uniquely heavy environmental burdens, and U.S. environmental groups have challenged the process by which the United States authorizes cross-border oil pipelines. This thesis analyzes the presidential permitting process and concludes that executive or legislative action is necessary to eliminate legal uncertainties and improve the transparency and public acceptability of determinations that new cross-border pipelines are warranted. / text
310

Russia's strategic natural gas export policy : the case of Gazprom's 'bypass' pipelines

Chyong, Chi Kong January 2011 (has links)
No description available.

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