• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 4
  • 2
  • 1
  • 1
  • Tagged with
  • 12
  • 12
  • 3
  • 3
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 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.
1

Three-phase gas/liquid/liquid slug flow

Odozi, Utomi Ayodele January 2000 (has links)
No description available.
2

Convergence on cooperation: the driving factors In U.S. and Russian cooperation on Belarus

Brown, Joseph W. 09 1900 (has links)
Russia / Belarus / Oil Pipelines / Democratic Revolution / As the last dictatorship in Europe, Belarus is a "problem state" for the United States. This thesis analyses U.S. interests in Belarus and assesses the extent of interdependence of these interests with Russian interests there. It first establishes a theoretical framework for U.S. and Russian national interests and the possibility for cooperation between the two countries. It then examines the mutuality of U.S and Russian interests in Belarus in the areas of democracy and human rights, drug and human trafficking, arms proliferation, oil and gas transit, and Russo-Belarusian trade and political integration and the policy options available to each country. Next, other elements of cooperation are applied to the situation in Belarus. Finally, the possibilities for cooperation are evaluated. This thesis demonstrates that the achievement of U.S. interests is significantly constrained by Russia's willingness to cooperate and that the United States can best achieve its objectives only through cooperation with Russia. This cooperation should center on neither country's first preference, but a compromise solution involving the ascendance of a moderate opponent to Lukashenka from within the Belarusian elite.
3

Application and development of advanced engineering geographical information systems for pipeline design

Winning, Herbert Keith January 2015 (has links)
This thesis proposes the use of an Advanced Engineering Geographical Information System (AEGIS) for the improved design of onshore pipelines, from concept to operation. The system is novel in that it is function rather than discipline or software specific. The thesis statement has been developed, and an aim and set of research objectives identified (along with the success criteria for the evaluation of the system), based on a review of current pipeline design methods. Drawing on a design science research methodology (DSRM), the thesis proposes the development of the system as an artefact in order to validate the proposed constructs, models, methods and implementations. The thesis discusses the underlying issues of data interoperability, the application of open data standards, and the integration of computer aided design (CAD) and geographical information systems (GIS). These challenges are addressed in the thesis and demonstrated through the implementation of the system. To support the development of the system, research was undertaken in the fields of pipeline engineering, environmental engineering and engineering design. As part of this research, a number of peer-reviewed journal papers were published, and conference papers presented in Kampala, Houston, London and Split. These papers covered the key fields contained in the thesis including, fluid mechanics, bio-systems engineering, environmental engineering, CAD/GIS integration (CGI), and the application and development of geospatial pipeline data models. The thesis concludes that the approach is valid, offering significant improvement across all fields compared to the current method of pipeline design. By taking a functional approach to the challenges of the design of pipelines, a system has been developed that addresses the requirements of the pipeline engineer, environmental engineer and engineering designer. The system enables the user to select the software of their choice, thereby reducing the problems associated with data interoperability, retraining and system integration. The sharing of data and outputs from analysis carried out within the system, provides an integrated approach, which can subsequently be used for the integrity management of the pipeline during the operational phase of the project. The scope for further development of this approach to pipeline design is also discussed. In addition to the inclusion of further engineering and environmental analysis, there is the potential for using the system for the design of subsea pipelines.
4

Challenges and countermeasures of China's energy security

Yang, Fan, Wang, Dongcan January 2015 (has links)
To ensure energy security, the first to know what is energy, and second, what are the factors of non-security, means that the challenge of energy security. Finally, puts forward some policy or in the case of a reasonable method to solve it according to these problems. At present, energy security is facing two challenges of structural crisis and crisis management system. Concretely, main problems in that security are analyzed, which are considered to affect China and mostly embody in such four big areas as the great pressure in energy supply, the scarcity of relative energy resources, foreign oil dependence is too large, crisis management systems of energy security, the shortage of green energy. Furthermore the counter measures concerned are proposed, including saving energy and increasing the energy utilization rate, to establish strategic energy reserves, strengthening environmental protection and adjusting the primary energy structure. China's rapid economic growth lead to sharp increase in oil imports. Due to China relies on a single chokepoint, the Malacca Strait, which has caused a high degree of concern about the safety of its energy. Nearly three-quarters of its oil imports flowing through the Strait. In view of its strategic importance to China and China’s little sway on the waterway, this view is mainly focused on China’s energy demand and supply in two aspects of concern. The paper analysis of whether the current energy structure is appropriate and sustainable. Because the energy security is facing China's energy is more and more dependent on imported fuel and the need to convert energy to meet the demand of modern society and the rapid growth of the requirements of the economic challenges. Concludes that the China's new policy should focus on energy efficiency, energy saving, renewable energy and turned to the main energy source of natural gas.
5

Ruská federace - energetická politika a ekonomizace zahraniční politiky / Russian federation - energy policy and economization of foreign policy

Řezáč, Tomáš January 2011 (has links)
The paper clearly shows that Russia has been diversifying its export routes during past 20 years, in order to by-pass third countries and to avoid paying additional transportation fees. The overall Russian export capacities of oil and gas are increasing, but in the same time the export volumes are stagnant. In case of oil transportation, pipelines are progressively substituted by sea transport, which enables Russia to participate on the world market. Situation with gas is different. Despite increasing export capacity Russia nowadays export almost the same amount of gas to the same locations as it did in 1990. It means that if there is any political or economical pressure it is laid against transition countries, which can be substituted, rather than against importing countries. Russian economical gains from export are following increasing oil and gas prices. To make the gains even higher, Russia initiated transition to world gas prices in the CIS countries as well as at the domestic market. To support the hypothesis of this thesis that primary goal of Russia is to increase its economical gains rather than to strengthen its political leverage, it is important to mention that majority of energy disputes of past twenty years were ignited by quarrel over prices and were settled by trade agreement. The...
6

An?lise qu?mica de produtos de incrusta??o em dutos de petr?leo por espectometria de fluoresc?ncia de raios X

Sena, Caio Patr?cio de Souza 28 July 2008 (has links)
Made available in DSpace on 2014-12-17T15:41:46Z (GMT). No. of bitstreams: 1 CaioPSSpdf.pdf: 3119135 bytes, checksum: 46f81d35762fa5844ea534c57d40d0b2 (MD5) Previous issue date: 2008-07-28 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The quantitative chemical characterization of the inorganic fraction of scale products is very relevant in studying, monitoring and controlling corrosive processes of oil pipelines. The X-ray fluorescence spectrometry (XRF) is a very versatile analytical technique, which can be used in quantitative analysis in solid samples at low concentrations of the chemical element, in the order of few ppm. A methodology that involves sample preparation diluted in the proportion of 1:7 (one portion of the sample for seven of wax), pressed as pellets was used in the XRF calibration for chemical analysis of scale products from oil pipelines. The calibration involved the preparation of reference samples from mixtures of P.A. reagents, aiming to optimize the time consumed in the steps of sample preparation and analysis of Al, Ba, Ca, Fe, K, Mg, Mn, Na, P, S, Si, Sr and Ti, using the same pressed pellet for trace and major elements analysis / A caracteriza??o qu?mica quantitativa da fra??o inorg?nica de produtos de incrusta??o ? de grande relev?ncia no estudo, monitoramento e controle de processos corrosivos em dutos de petr?leo. A espectrometria por fluoresc?ncia de raios X (EFRX) ? uma t?cnica anal?tica muito vers?til, que pode ser utilizada na obten??o de resultados quantitativos de amostras s?lidas em baixas concentra??es do elemento qu?mico, da ordem de alguns ppm. Uma metodologia de prepara??o de amostras dilu?das na propor??o de 1:7 (uma por??o de amostra para sete de cera), posteriormente prensadas na forma de pastilhas foi utilizada na calibra??o do EFRX para an?lise de produtos de incrusta??o de dutos de petr?leo. O processo de calibra??o envolveu a confec??o de amostras de refer?ncia a partir de misturas de reagentes P.A., onde se buscou a otimiza??o do tempo envolvido nas etapas de prepara??o de amostras e an?lise dos elementos Al, Ba, Ca, Fe, K, Mg, Mn, Na, P, S, Si, Sr e Ti, utilizando-se as mesmas pastilhas para dosagem de elementos tra?os e maiores
7

Proposta de algoritmo para detec??o de vazamentos em oleodutos utilizando an?lise freq?encial de sinais de press?o

Azevedo, Fabiano Medeiros de 23 October 2009 (has links)
Made available in DSpace on 2014-12-17T14:55:40Z (GMT). No. of bitstreams: 1 FabianoMA.pdf: 3389870 bytes, checksum: 6be9485b031563d3dfbff4f86c5c0c69 (MD5) Previous issue date: 2009-10-23 / Petr?leo Brasileiro SA - PETROBRAS / Pipeline leak detection is a matter of great interest for companies who transport petroleum and its derivatives, in face of rising exigencies of environmental policies in industrialized and industrializing countries. However, existing technologies are not yet fully consolidated and many studies have been accomplished in order to achieve better levels of sensitivity and reliability for pipeline leak detection in a wide range of flowing conditions. In this sense, this study presents the results obtained from frequency spectrum analysis of pressure signals from pipelines in several flowing conditions like normal flowing, leakages, pump switching, etc. The results show that is possible to distinguish between the frequency spectra of those different flowing conditions, allowing recognition and announce of liquid pipeline leakages from pressure monitoring. Based upon these results, a pipeline leak detection algorithm employing frequency analysis of pressure signals is proposed, along with a methodology for its tuning and calibration. The proposed algorithm and its tuning methodology are evaluated with data obtained from real leakages accomplished in pipelines transferring crude oil and water, in order to evaluate its sensitivity, reliability and applicability to different flowing conditions / A detec??o de vazamentos em dutos ? assunto de grande interesse para empresas que realizam o transporte de petr?leo e seus derivados, tendo em vista o crescente rigor da legisla??o ambiental nos pa?ses industrializados e em processo de industrializa??o. No entanto, as tecnologias existentes hoje ainda n?o est?o plenamente consolidadas e estudos v?m sendo realizados com vistas a atingir maiores n?veis de sensibilidade e confiabilidade para a detec??o de vazamentos em uma ampla variedade de regimes de escoamento. Neste sentido, este estudo apresenta os resultados obtidos com a an?lise do espectro de freq??ncia de sinais de press?o de oleodutos em diversas situa??es de escoamento, tais como escoamento normal, vazamentos, partida e parada de bombas, etc. Os resultados indicam que ? poss?vel diferenciar o espectro freq?encial dessas diferentes condi??es de escoamento, o que permite reconhecer e indicar a ocorr?ncia de vazamentos em dutos transportando fluidos l?quidos a partir da monitora??o de sua press?o. Com base nestes resultados, s?o propostos um algoritmo para detec??o de vazamentos em dutos utilizando a an?lise freq?encial de sinais de press?o e uma metodologia para sintonia e calibra??o deste algoritmo. O algoritmo e a metodologia de sintonia propostos s?o avaliados com dados obtidos a partir de vazamentos reais provocados em dutos transferindo petr?leo e ?gua, a fim de avaliar sua sensibilidade, confiabilidade e aplicabilidade para diferentes condi??es de escoamento
8

Estudos laboratoriais para avaliação do ootencial de contaminação de água e de solo por gasolina oxigenada. / Laboratory studies to evaluation of the potential of groundwater and soil contamination by oxygenated gasoline.

Ferreira, Sayonara Brederode 24 January 2000 (has links)
Em muitos países e principalmente no Brasil, compostos oxigenados tais como etanol e metil terta-butil-éter (MTBE) têm sido adicionados à gasolina em cerca de 26% do seu volume para aumentar a octanagem do motor e diminuir a emissão de monóxido de carbono e os níveis de ozônio na atmosfera. O derramamento de tais gasolinas, referidas como gasolina oxigenada tem um efeito cosolvente, provocando um aumento da concentração dos hidrocarbonetos na água subterrânea. A taxa de dissolução em água da gasolina oxigenada, que é dependente das propriedades químicas dos compostos orgânicos, determinam o grau e a severidade de contaminação da água subterrânea nas vizinhanças do derramamento. O objetivo do trabalho foi analisar e quantificar o potencial de contaminação da água subterrânea e de solos arenosos residuais dos arenitos da Formação Botucatu por derramamento de gasolina oxigenada. As análises realizadas buscam fornecer dados para a modelagem numérica em casos envolvendo derramamento de gasolina. Ensaios de equilíbrio em lote e de dissolução em colunas foram realizados objetivando a determinação da concentração aquosa de hidrocarbonetos da gasolina em equilíbrio de fases e a avaliação do tempo estimado para total dissolução em água dos hidrocarbonetos da gasolina pura. Ambos os ensaios analisaram também o efeito cosolvente do etanol na mistura. Verificou-se a validade da lei de Raoult e do modelo log-linear na determinação da concentração aquosa da gasolina pura e oxigenada. Em colunas de solos não saturados avaliou-se a difusão na fase vapor dos compostos orgânicos da gasolina em função do tempo. Finalizando as análises, fez-se uma simulação numérica do transporte da gasolina em zonas não saturadas fazendo-se uso do programa R-UNSAT. / In many countries and mainly in Brazil oxygenated compounds such as ethanol and MTBE have been added to gasoline up to 26% to increase the octane level and to reduce carbon monoxide and ozone levels in the air. The spill of such gasolines, referred as oxygenated gasoline has a potential cosolvent effect, resulting in an increased groundwater concentration of hydrocarbons. The rate of oxygenated gasoline dissolution, which is dependent of the chemical properties of the compounds, determines the degree and severity of groundwater contamination in the vicinity of the spill. The goal of this research was to analyze and to quantify the potential of contamination of the groundwater and of the residual sandy soils from Botucatu sandstone due to the spill of oxigenated gasoline. The performed analysis supply data to the numerical model in case of gasoline spills. Laboratory batch and column leaching tests were carried out in order to determine the equilibrium aqueous concentration of the hydrocarbons compounds of gasoline and to evaluate the time scale for aqueous dissolution of the hydrocarbons compounds. Both tests have analyzed the cosolvent effect of ethanol in the mixture. It was verified the validity of the Raoult's law and the log-linear cosolvency model to estimate the solubility of the hydrocarbons compounds from unamended gasoline and from oxygenated gasoline. Column tests with unsaturated undisturbed soil samples were carried out to investigate the vapor-phase diffusion of aromatic hydrocarbons compounds with time. Finally the transport of gasoline in unsaturated zones was simulated with the R-UNSAT model.
9

Estudos laboratoriais para avaliação do ootencial de contaminação de água e de solo por gasolina oxigenada. / Laboratory studies to evaluation of the potential of groundwater and soil contamination by oxygenated gasoline.

Sayonara Brederode Ferreira 24 January 2000 (has links)
Em muitos países e principalmente no Brasil, compostos oxigenados tais como etanol e metil terta-butil-éter (MTBE) têm sido adicionados à gasolina em cerca de 26% do seu volume para aumentar a octanagem do motor e diminuir a emissão de monóxido de carbono e os níveis de ozônio na atmosfera. O derramamento de tais gasolinas, referidas como gasolina oxigenada tem um efeito cosolvente, provocando um aumento da concentração dos hidrocarbonetos na água subterrânea. A taxa de dissolução em água da gasolina oxigenada, que é dependente das propriedades químicas dos compostos orgânicos, determinam o grau e a severidade de contaminação da água subterrânea nas vizinhanças do derramamento. O objetivo do trabalho foi analisar e quantificar o potencial de contaminação da água subterrânea e de solos arenosos residuais dos arenitos da Formação Botucatu por derramamento de gasolina oxigenada. As análises realizadas buscam fornecer dados para a modelagem numérica em casos envolvendo derramamento de gasolina. Ensaios de equilíbrio em lote e de dissolução em colunas foram realizados objetivando a determinação da concentração aquosa de hidrocarbonetos da gasolina em equilíbrio de fases e a avaliação do tempo estimado para total dissolução em água dos hidrocarbonetos da gasolina pura. Ambos os ensaios analisaram também o efeito cosolvente do etanol na mistura. Verificou-se a validade da lei de Raoult e do modelo log-linear na determinação da concentração aquosa da gasolina pura e oxigenada. Em colunas de solos não saturados avaliou-se a difusão na fase vapor dos compostos orgânicos da gasolina em função do tempo. Finalizando as análises, fez-se uma simulação numérica do transporte da gasolina em zonas não saturadas fazendo-se uso do programa R-UNSAT. / In many countries and mainly in Brazil oxygenated compounds such as ethanol and MTBE have been added to gasoline up to 26% to increase the octane level and to reduce carbon monoxide and ozone levels in the air. The spill of such gasolines, referred as oxygenated gasoline has a potential cosolvent effect, resulting in an increased groundwater concentration of hydrocarbons. The rate of oxygenated gasoline dissolution, which is dependent of the chemical properties of the compounds, determines the degree and severity of groundwater contamination in the vicinity of the spill. The goal of this research was to analyze and to quantify the potential of contamination of the groundwater and of the residual sandy soils from Botucatu sandstone due to the spill of oxigenated gasoline. The performed analysis supply data to the numerical model in case of gasoline spills. Laboratory batch and column leaching tests were carried out in order to determine the equilibrium aqueous concentration of the hydrocarbons compounds of gasoline and to evaluate the time scale for aqueous dissolution of the hydrocarbons compounds. Both tests have analyzed the cosolvent effect of ethanol in the mixture. It was verified the validity of the Raoult's law and the log-linear cosolvency model to estimate the solubility of the hydrocarbons compounds from unamended gasoline and from oxygenated gasoline. Column tests with unsaturated undisturbed soil samples were carried out to investigate the vapor-phase diffusion of aromatic hydrocarbons compounds with time. Finally the transport of gasoline in unsaturated zones was simulated with the R-UNSAT model.
10

The Effect of Corrosion Defects on the Failure of Oil and Gas Transmission Pipelines: A Finite Element Modeling Study

Orasheva, Jennet 01 January 2017 (has links)
The transportation of oil and gas and their products through the pipelines is a safe and economically efficient way, when compared with other methods of transportation, such as tankers, railroad, trucks, etc. Although pipelines are usually well-designed, during construction and later in service, pipelines are subjected to a variety of risks. Eventually, some sections may experience corrosion which can affect the integrity of pipeline, which poses a risk in high-pressure operations. Specifically, in pipelines with long history of operation, the size and location of the corrosion defects need to be determined so that pressure levels can be kept at safe levels, or alternatively, a decision to repair or replace the pipe section can be made. To make this decision, there are several assessment techniques available to engineers, such as ASME B31G, MB31G, DNV-RP, software code called RSTRENG. These assessment techniques help engineers predict the remaining strength of the wall in a pipe section with a corrosion defect. The corrosion assessment codes in the United States, Canada and Europe are based on ASME-B31G criterion for the evaluation of corrosion defects, established based on full-scale burst experiments on pipes containing longitudinal machined grooves, initially conducted in 1960s. Because actual corrosion defects have more complex geometries than machined grooves, an in-depth study to validate the effectiveness of these techniques is necessary. This study is motivated by this need. The current study was conducted in several stages, starting with the deformation behavior of pipe steels. In Phase 1, true-stress-true plastic strain data from the literature for X42 and X60 steel specimens were used to evaluate how well four commonly used constitutive equations, namely, those developed by Hollomon, Swift, Ludwik and Voce, fit the experimental data. Results showed that all equations provided acceptable fits. For simplicity, the Hollomon equation was selected to be used in the rest of the study. In Phase 2, a preliminary finite element modeling (FEM) study was conducted to compare two failure criteria, stress-based or strain-based, performed better. By using data from the literature for X42 and X60 pipe steels, experimental burst pressure data were compared with predicted burst pressure data, estimated based on the two failure criteria. Based on this preliminary analysis, the stress-based criterion was chosen for further FEM studies. In Phase 3, failure data from real corrosion pits in X52 pipe steels with detailed profiles were used to develop a FEM scheme, which included a simplified representation of the defect. Comparison of actual and predicted burst pressures indicated a good fit, with a coefficient of determination (R2) level of 0.959. In Phase 4, burst pressure levels were estimated for real corrosion pits for the experiments from the same study as in Phase 3, but only with corrosion pit depths and length and without corrosion widths. Widths were estimated from the data used in Phase 3, by using an empirical equation as a function of pit length. There was significant error between experimental and predicted burst pressure. Errors in Phases 3 and 4 were compared statistically. Results showed that there is a statistically significant difference in the error when the width of the corrosion pit is unknown. This finding is significant because none of the assessment techniques in the literature takes width into consideration. Subsequently, a parametric study was performed on three defect geometries from the same study in Phase 3. The pit depths and lengths were held constant but widths were changed systematically. In all cases, the effect of the pit width on burst pressure was confirmed. In Phase 5, the three assessment techniques, ASME B31G, MB31-G and DNV-RP were evaluated by using experimental test results for X52 pipe. Synthetic data for deeper pits were developed by FEM and used along with experimental data in this phase. Two types of the error were distinguished to classify defects. Type I errors (α) and Type II errors (β) were defined using Level 0 evaluation method. Results showed that although ASME B31G is the most conservative technique, it is more reliable for short defects than MB31G and DNV-RP. The least conservative technique was DNV-RP but it yielded β error, i.e., the method predicted a safe operating pressure and pipe section would fail. Therefore, DNV-RP is not recommended for assessment of steel pipes, specifically for X52 pipes.

Page generated in 0.0696 seconds