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Simulação numérica do escoamento de óleo em um duto submerso com orifício de vazamento. / Numerical simulation of the oil flow in a submerged duct with leakage orifice.MOREIRA, Gicélia. 12 March 2018 (has links)
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Previous issue date: 2016-03-30 / Vazamento em oleodutos, além de prejuízos financeiros pode causar diversos danos ambientais, onde, o conhecimento dos fenômenos interfaciais de líquidos imiscíveis permite entender o processo de migração advectiva em dutos submarinos. Portanto, estas informações, possibilitam prever o comportamento e a forma geométrica da interface água-óleo e fornecer uma boa fundamentação fenomenológica no que diz respeito às teorias de perturbação, aos critérios de estabilidade e a modelagem matemática, bem como os padrões de escoamento nas vizinhanças do
vazamento em dutos submersos. Diante disto, este trabalho, tem por objetivo estudar
numericamente a influência do vazamento de óleo no mar a partir de duto submerso e vice-versa sobre o comportamento de fluidos. Para isso, adotou-se um modelo bidimensional com base nas equações de conservação de massa, momento linear e o modelo de turbulência k-ε padrão disponibilizado no Ansys CFX. O comportamento dinâmico do óleo e da água é representado com auxílio de campos de pressão, velocidade superficial e fração volumétrica de óleo e da água, vetores de velocidade. Os resultados das simulações indicam a presença de vazamento de óleo na correnteza marítima e de água para a corrente de óleo no tubo através do orifício de vazamento. / Leaks in pipelines, beyond financial losses can cause various environmental damage, where the knowledge of interfacial phenomena of immiscible liquids allows us to understand the advective migration process in subsea pipelines. Therefore, these informations allows to predict the behavior and geometrical form of water-oil interface and provide a good phenomenological foundation with respect to the theories of perturbation, the criteria of stability and the mathematical model as well as the flow patterns in around of the leakage starting from underwater pipelines. In view of this, this work aims to numerically study the influence of the oil leak in the sea starting from submerged
pipe or the opposite about behavior of fluids. For this, it was adopted a two-dimensional model based on mass conservation and linear momentum equations and the k-ε standard turbulence model available in Ansys CFX. The dynamic behavior of oil and water is shown with the aid of pressure, superficial velocity and volumetric fraction fields of oil and water and velocity vectors. The simulation results indicate the presence of oil spills in sea water in the stream and the water for oil tube through of the orifice leakage.
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Optimalizace předooperační a operační léčby karcinomu jícnu a ezfago-gatstrické junkce: využití PET/CT v diagnostice a hodnocení efektivity předoperační chemoterapie a technika konstrukce anastomozy jako faktor pooperačních komplikací po ezofagektomii / Optimization of preoperative and surgical treatment of carcinoma of the esophagus and esophagogastric junction: The use of PET/CT in the diagnosis and evaluation of the effectiveness of preoperative chemotherapy and the technique of anastomotic construction as a factor of postoperative complications after esophagectomyHaruštiak, Tomáš January 2017 (has links)
Key words: adenocarcinoma of the esophagus and esophagogastric junction, neoadjuvant chemotherapy, PET/CT, histopathological response, technique of esophagogastric anastomosis, anastomotic leak, anastomotic stricture Previous studies have shown that preoperative chemotherapy of locally advanced AEG is beneficial only for patients with a good histopathological response, the so-called responders. The aim of the first part of the thesis was to prospectively verify whether positron emission tomography (PET/CT) could be used for early identification of histopathological non- responders, who could be spared ineffective neoadjuvant treatment. Our study did not prove that the early metabolic response, expressed as the percentage change of the consumption of glucosis on PET/CT performed before (PET1) and 12 to 22 days after the start of the first cycle of preoperative chemotherapy (PET2) correlated with the histopathological response in the resection specimen in the entire population of 90 patients. In a post hoc explorative analysis we found the correlation between metabolic and histopathological response in a subgroup of patients with PET2 performed ≤16 days after the start of the therapy, but this hypothesis needs to be prospectively validated. Our study suggests that PET/CT performed after the first...
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Simulação de escoamentos transientes em dutos de transporte de líquidos / Simulation of transient flow in pipelines for the transportation of liquidsSantos, Fernanda Olegario dos 08 July 2010 (has links)
O transporte de fluidos e produtos petroquímicos através de malhas dutoviárias é uma opção extremamente difundida, tanto em aplicações industriais envolvendo longas distâncias quanto em sistemas de distribuição nos quais um determinado fluido deve ser entregue a um grande número de usuários ou processos. Em ambos os casos, para uma operação eficiente e segura da malha, é necessário um sistema de detecção de vazamentos, que detecta e avalia rapidamente a ocorrência de um vazamento, especialmente quando o fluido transportado for tóxico e/ou inflamável. Neste sentido, a análise hidráulica em escoamentos transitórios tem sido particularmente útil aos propósitos de detecção de vazamentos. Sistemas de observação para essa análise podem revelar uma quantidade substancial de informações relativas às propriedades físicas e o nível de integridade do sistema, pois as ondas de pressão resultantes são afetadas pelos diversos dispositivos e fenômenos, incluindo os vazamentos. Este trabalho apresenta a construção e validação de um modelo de simulação numérica adequado para uma nova técnica de detecção de vazamento, baseada na inspeção acústica ativa da tubulação, capaz de detectar vazamentos pré-existentes. Resultados numéricos foram comparados com os obtidos de ensaios experimentais realizados no oleoduto piloto do Laboratório de Escoamentos Multifásicos Industriais da Universidade de São Paulo, no campus de São Carlos - SP e de dados experimentais da literatura. Os resultados confirmam que o modelo numérico capta corretamente a física do fenômeno de propagação. Particularmente, uma boa concordância foi encontrada entre parâmetro de atenuação experimental e numérico, o que valida o modelo como um preditor on-line para ser usado em um sistema de detecção de vazamento. / The transportation of petrochemical products through pipelines is the most common option, both in industrial applications involving long distances as well as in distribution networks in which a product must be delivered to a number of processes or customers. Due to safety and environmental reasons, the operation of such pipelines must include an on-line Leak Detection System (LDS) which promptly detects and assesses the occurrence of a leak, particularly if the transported product is toxic or inflammable. Analysis of hydraulic transients has been particularly useful for leak detection purposes. System observation for such analysis can reveal a substantial amount of information concerning physical properties and the integrity of the system, since pressure waves are affected by different features and phenomena, including leaks. This work presents the construction and validation of a numerical model suited to the simulation of a new leak detection technique, based on active acoustic inspection of the pipeline, which is capable of detecting pre-existing leaks. Numerical results were compared to the ones obtained from experimental tests conducted at the pilot pipeline of the Industrial Multiphase Flow Laboratory at University of São Paulo in the campus of São Carlos - SP and experimental data from literature. Results confirm that the numerical model captures the correct physics of the propagation phenomena. Particularly, a good agreement was found between experimental and numerical attenuation parameter, which validates our model as an on-line predictor to be used in a LDS system.
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Extração de parâmetros característicos para detecção acústica de vazamento de água. / Feature extraction for acoustic water leak detection.Borges, Liselene de Abreu 08 April 2011 (has links)
Este trabalho apresenta a pesquisa sobre a extração de parâmetros característicos de sinais acústicos para fins de detecção automática de vazamento de água em tubulações enterradas. Os sinais acústicos foram adquiridos com o auxílio de um geofone eletrônico e também catalogados por técnicos especialistas em detecção acústica. De todos os sinais foram extraídos os modelos de predição linear perceptual de várias ordens, determinando-se como melhor a ordem 2. A partir de um conjunto de modelos de referência de sinais de vazamento, a distância média de Itakura dos outros modelos em relação a estas referências foram calculadas. Em conjunto com estas distâncias, quatro características espectrais são também extraídas do sinal a fim de compor o vetor de parâmetros característicos do sinal. Parte destes vetores de parâmetros característicos são utilizados para treinar o classificador de máquina de vetores de suporte. O restante dos dados são, então, submetidos a este classificador que obteve a taxa de acerto de classificação em torno de 93%. Experimentos anteriores, utilizando modelos de predição linear, de ordem 10, obtiveram uma taxa de acerto em torno de 82%. Isso demonstra que estes novos parâmetros característicos propostos alcançam os objetivos deste trabalho, que são algoritmos com melhor taxa de acerto na detecção de vazamentos. / This work presents a research about feature extraction of acoustic signals for detection of water leak in buried pipes. Acoustic signals were acquired by means of an electronic geophone and also labeled by technicians specialized in acoustic water leak detection. For every signals, its linear predictive model was estimated for a range of prediction orders, concluding for the best order 2. Out of this group of models, some leaky ones are used as reference for calculating the Itakura mean distance with respect to the other models. Completing this measure, four spectral features are extracted to compose the signal feature vector. Some of these vectors were used to train a support vector machine to be used as a classifier. The remaining ones were used to evaluate the classification. The resulting accuracy rate achieved is around 93%. Earlier experiments, which use linear prediction of order 10 had an accuracy rate around 82%. This shows that this novel proposal of feature vector achieves the main goal of this research, which is the increase in the leak detection accuracy rate.
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Análise tempo-frequência de ondas acústicas em escoamentos monofásicos / Time-frequency analysis of acoustic waves in single-phase flowLima, Simone Rodrigues 22 December 2010 (has links)
A presente dissertação tem como objetivo principal estudar a propagação acústica em escoamentos monofásicos. Para tal, são analisados sinais transientes de pressão fornecidos por sensores instalados em posições conhecidas na linha de teste, através do estudo de técnicas de análise de sinais, a fim de investigar se as variações do conteúdo espectral dos sinais são influenciadas pela ocorrência de vazamentos no duto. A análise dos sinais foi realizada nos planos temporal, frequencial, tempo-frequência e estatístico. Os resultados experimentais foram obtidos no oleoduto piloto do NETeF - Núcleo de Engenharia Térmica e Fluidos da USP - Universidade de São Paulo, com uma seção de testes com 1500 metros e diâmetro de 51,2 mm, com escoamento monofásico de água. Os resultados obtidos através da análise tempo-frequência mostraram-se satisfatórios, sendo esta técnica capaz de identificar a composição espectral instantânea de um sinal, ou seja, foi eficiente na identificação de picos de amplitude da frequência ao longo do eixo temporal. Além disso, a análise probabilística, através do desvio-padrão do sinal também mostrou-se eficiente exibindo uma disparidade significativa entre os sinais com e sem vazamento. / The present dissertation reports on the study of the acoustic propagation in single-phase flow. It analyzes the transient signals provided by pressure sensors in known locations in the test line through the study of signal analysis techniques to investigate if the variations in spectral content of the signals are influenced by the occurrence of leaks in the pipe. The analysis of signals was performed in the time, frequency, time-frequency and statistical plans. The experimental results were obtained in a 1500 meter-long and 51.2 millimeter-diameter pilot pipeline at the Center of Thermal Engineering and Fluids, with single-phase flow of water. The results obtained by time-frequency analysis were satisfactory, allowing identifying the spectral composition of an instantaneous signal, i.e., the analysis was effective in identifying the frequency amplitude peaks along the time axis. Moreover, probabilistic analysis using the standard deviation of the signal was also efficient, displaying a significant disparity between the signals with and without leakage.
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Study of the cosmic muon-induced background for the theta 13 angle in the Double Chooz neutrino oscillation experiment / Étude du bruit de fond d'origine cosmique pour la mesure de l'angle de mélange theta 13 au sein de l'expérience Double ChoozKale Sayi, Kenny 09 July 2018 (has links)
L’expérience Double Chooz, située sur le site de la centrale nucléaire de Chooz dans la région des Ardennes en France, étudie la disparition des antineutrinos. Le but principal de l’expérience est de mesurer avec une grande précision l’amplitude d’oscillation sin2 2θ13 des antineutrinos émis par les deux réacteurs de la centrale de Chooz. La précision de cette mesure dépend fortement d’une connaissance précise des taux et de la forme des spectres des bruits de fond qui contaminent la sélection finale des antineutrinos en particulier dans la gamme d’énergie où l’oscillation des neutrinos est attendue. Nous avons étudié dans la présente thèse le bruit de fond d’origine cosmique dans l’expérience Double Chooz. En effet, les muons cosmiques traversant les détecteurs ou interagissant dans le voisinage immédiat sont la principale source de bruit de fond observés dans l’expérience Double Chooz. Deux types de bruits de fonds sont analysés et présentes dans cette thèse : les neutrons rapides (FN) et la double capture de neutrons (DnC). Des techniques d’identification dédiées ont été développées pour chacun de ces bruits de fond et, par conséquent, les formes spectrales et les taux associés ont été́ déterminés. Les valeurs obtenues dans le cadre de ce travail servent de paramètres d’entrée dans le fit final d’où la valeur de θ13 est extraite. La dernière mesure publiée par la collaboration Double Chooz est sin2 2θ13 = 0.119 ± 0.016. / The Double Chooz experiment is- a reactor antineutrino disappearance experiment located on the site of the Chooz nuclear power plant in the Ardennes region in France. The principal aim of the experiment is a high precision measurement of the oscillation amplitude sin2 2θ13 of the antineutrinos emitted from the two reactor cores of the Chooz power plant. The robustness and accuracy of this measurement depends strongly on a precise knowledge of the rates and spectral shapes of the backgrounds that contaminate the antineutrinos selection over the neutrino oscillation expected region. We have studied in the present thesis the muon induced background in the Double Chooz experiment. Indeed, cosmic muons crossing the detectors or interacting in the neighborhood constitute the main source of background events encountered in Double Chooz. Two distinct backgrounds analysis are presented in this thesis: fast neutrons (FN) and double capture of neutrons (DnC). Dedicated identification techniques have been developed for each of these backgrounds and, consequently, the associated spectral shapes and rates have been determined. The values obtained in this work serve as inputs in the final fit whence the θ13 value is extracted.The latest measurement released by the Double Chooz collaboration is sin2 2θ13 = 0.119 ± 0.016$.
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Extração de parâmetros característicos para detecção acústica de vazamento de água. / Feature extraction for acoustic water leak detection.Liselene de Abreu Borges 08 April 2011 (has links)
Este trabalho apresenta a pesquisa sobre a extração de parâmetros característicos de sinais acústicos para fins de detecção automática de vazamento de água em tubulações enterradas. Os sinais acústicos foram adquiridos com o auxílio de um geofone eletrônico e também catalogados por técnicos especialistas em detecção acústica. De todos os sinais foram extraídos os modelos de predição linear perceptual de várias ordens, determinando-se como melhor a ordem 2. A partir de um conjunto de modelos de referência de sinais de vazamento, a distância média de Itakura dos outros modelos em relação a estas referências foram calculadas. Em conjunto com estas distâncias, quatro características espectrais são também extraídas do sinal a fim de compor o vetor de parâmetros característicos do sinal. Parte destes vetores de parâmetros característicos são utilizados para treinar o classificador de máquina de vetores de suporte. O restante dos dados são, então, submetidos a este classificador que obteve a taxa de acerto de classificação em torno de 93%. Experimentos anteriores, utilizando modelos de predição linear, de ordem 10, obtiveram uma taxa de acerto em torno de 82%. Isso demonstra que estes novos parâmetros característicos propostos alcançam os objetivos deste trabalho, que são algoritmos com melhor taxa de acerto na detecção de vazamentos. / This work presents a research about feature extraction of acoustic signals for detection of water leak in buried pipes. Acoustic signals were acquired by means of an electronic geophone and also labeled by technicians specialized in acoustic water leak detection. For every signals, its linear predictive model was estimated for a range of prediction orders, concluding for the best order 2. Out of this group of models, some leaky ones are used as reference for calculating the Itakura mean distance with respect to the other models. Completing this measure, four spectral features are extracted to compose the signal feature vector. Some of these vectors were used to train a support vector machine to be used as a classifier. The remaining ones were used to evaluate the classification. The resulting accuracy rate achieved is around 93%. Earlier experiments, which use linear prediction of order 10 had an accuracy rate around 82%. This shows that this novel proposal of feature vector achieves the main goal of this research, which is the increase in the leak detection accuracy rate.
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An Investigation Of The Leak-off Tests Conducted In Oil And Natural Gas Wells Drilled In Thrace BasinKayael, Burak 01 February 2012 (has links) (PDF)
This study aims to analyze the leak-off tests carried out in the Thrace Basin of Turkey by Turkish Petroleum Corporation and find any relationship that may exist between leak-off test results and drilled formations as well as drilling parameters, such as mud weight, depth.
The analysis of 77 leak-off tests indicated that there is no close correlation between the mud weight of test fluid and equivalent mud weight (fracture gradient) if the test is carried out within impermeable sections. On the other hand, the correlation between mud weight and equivalent mud weight increase while running the test within permeable-productive zones. It is also found that the leak-off test results are not dependent on the depth but the formation to be tested.
The analyzed leak-off test results from Thrace Basin showed that the fracture gradient is not the limiting factor to set the casing of any section unless a gas show is observed during drilling operation which occurred only in 5 wells out of 78 wells
analyzed.
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A pre-study on the compressed air system at Ljunghaell AB / En förstudie på tryckluftssystemet hos Ljunghäll ABNelson Berg, Joakim, Lee, Jonathan January 2014 (has links)
The Swedish industry uses large volumes of compressed air. The compressed air process isenergy intensive and creates large amounts of excess heat. It is therefore important to utilizethe excess heat, optimize the operation of the compressors and to have a regular maintenanceon the system. This thesis is a pre-study to make a compressed air system energy efficient andis done in collaboration with Ljunghäll AB. Ljunghäll AB is one of Northern Europe's leadingdie casting companies and are located in Södra Vi, Sweden. The purpose is to describe andmap the compressed air system in the old part of the facility in Södra Vi. The thesis will alsogive an explanation of how Ljunghäll AB can improve the compressed air system. Providethem suggestions for energy savings and lower the environmental impact of production. Theobjective of the thesis is to create an understanding of how improvements in the compressedair system can be done by studying the operation, compressor, pipe system and leak detecting.The economic aspects of the solutions together with the effect of noise and engine operationof the compressors have not been taken into consideration. To reach improvement measures avisit to the facility in Södra Vi was made, where measuring and mapping was executed andthen compared with earlier studies and literature. The conclusions of the thesis show thatLjunghäll AB has a good operation and control of the compressors, through the variable speeddrive and steering system. It also showed that the choice of the existing compressors are goodfor their compressed air usage. The study also resulted in the following suggestions for theenergy efficiency and lowering of the environmental impact of production at Ljunghäll AB’scompressed air system: Water heat recovery, replacement of old pipes, cover the leakage,regular maintenance of compressors and fittings, training in compressed air for workers,centralized compressor central and sectioning of the pipe system.
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Implementa??o de um M?dulo de Supervis?o para um Sistema de Detec??o de Vazamentos em Dutos de Petr?leoSilva, Rodrigo Eduardo Ferreira da 22 December 2009 (has links)
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Previous issue date: 2009-12-22 / The transport of fluids through pipes is used in the oil industry, being the pipelines an important link in the logistics flow of fluids. However, the pipelines suffer deterioration in their walls caused by several factors which may cause loss of fluids to the environment, justifying the investment in techniques and methods of leak detection to minimize fluid loss and environmental damage. This work presents the development of a supervisory module in order to inform to the operator the leakage in the pipeline monitored in the shortest time possible, in order that the operator log procedure that entails the end of the leak. This module is a component of a system designed to detect leaks in oil pipelines using sonic technology, wavelets and neural networks. The plant used in the development and testing of the module presented here was the system of tanks of LAMP, and its LAN, as monitoring network. The proposal consists of, basically, two stages. Initially, assess the performance of the communication infrastructure of the supervisory module. Later, simulate leaks so that the DSP sends information to the supervisory performs the calculation of the location of leaks and indicate to which sensor the leak is closer, and using the system of tanks of LAMP, capture the pressure in the pipeline monitored by piezoresistive sensors, this information being processed by the DSP and sent to the supervisory to be
presented to the user in real time / O transporte de fluidos atrav?s de tubula??es ? utilizado na ind?stria petrol?fera, sendo os dutos um elo importante na log?stica de escoamento de fluidos. Por?m, os dutos sofrem
deteriora??o em suas paredes ocasionadas por diversos fatores o que pode provocar a perda de fluidos para o meio exterior, justificando o investimento em t?cnicas e m?todos de detec??o de vazamentos para minimizar a perda do fluido e os danos ambientais provocados. Este trabalho apresenta o desenvolvimento de um m?dulo de supervis?o para que seja informado ao operador a ocorr?ncia de vazamento no duto monitorado no menor tempo poss?vel, com o prop?sito que o operador efetue procedimentos que acarretem no fim do vazamento. Esse m?dulo ? um componente de um sistema que visa ? detec??o de vazamento em dutos petrol?feros utilizando tecnologia s?nica, wavelets e redes neurais. A planta utilizada no desenvolvimento e testes do m?dulo aqui apresentado, foi o sistema de tanques do Laborat?rio de Avalia??o de Medi??o em Petr?leo (LAMP), e a sua Local Area Network (LAN), como rede de supervis?o. A proposta consiste, basicamente, de duas etapas. Inicialmente, avaliar o desempenho da infraestrutura de comunica??o do m?dulo de supervis?o. Posteriormente, simular vazamentos para que o DSP (Digital Signal Processor) envie informa??es para o supervis?rio realizar o c?lculo da localiza??o
dos vazamentos e indicar a qual sensor o vazamento ? mais pr?ximo, e usando o sistema de tanques do LAMP, capturar a press?o no duto monitorado atrav?s de sensores piezoresistivos,
sendo essa informa??o processada pelo DSP e enviada ao supervis?rio para que seja apresentado ao usu?rio dados em tempo real
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