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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.
31

Laboratory and modelling studies on the effects of injection gas composition on CO₂-rich flooding in Cooper Basin, South Australia.

Bon, Johannes January 2009 (has links)
This Ph.D. research project targets Cooper Basin oil reservoirs of very low permeability (approximately 1mD) where injectivities required for water flooding are not achievable. However, the use of injection gases such as CO₂ would not have injectivity problems. CO₂ is abundant in the region and available for EOR use. CO₂ was compared to other CO₂-rich injection gases with a hydrocarbon content including pentane plus components. While the effect of hydrocarbon components up to butane have been investigated in the past, the effect of n-pentane has on impure CO₂ gas streams has not. One particular field of the Cooper Basin was investigated in detail (Field A). However, since similar reservoir and fluid characteristics of Field A are common to the region it is expected that the data measured and developed has applications to many other oil reservoirs of the region and similar reservoirs elsewhere. The aim of this Ph.D. project is to determine the applicability of CO₂ as an injection gas for Enhanced Oil Recovery (EOR) in the Cooper Basin oil reservoirs and to compare CO₂ with other possible CO₂-rich injection gases. The summarised goals of this research are to: • Determine the compatibility of Field A reservoir fluid with CO₂ as an injection gas. • Compare CO₂ to other injection gas options for Field A. • Development of a correlation to predict the effect of nC₅ on MMP for a CO₂- rich injection gas stream. These goals were achieved through the following work: • Extensive experimental studies of the reservoir properties and the effects of interaction between CO₂-rich injection gas streams and Field A reservoir fluid measuring properties related to: • Miscibility of the injection gas with Field A reservoir fluid • Solubility and swelling properties of the injection gas with Field A reservoir fluid • Change in viscosity-pressure relationship of Field A reservoir fluid due to addition of injection gas • A reservoir condition core flood experiment • Compositional simulation of the reservoir condition core flood to compare expected recoveries from different injection gases • Development of a set of Minimum Miscibility Pressure (MMP) measurements targeted at correlating the effect of nC₅ on CO₂ MMP. The key findings of this research are as follows: • Miscibility is achievable at practical pressures for Field A and similar reservoir fluids with pure CO₂ or CO₂-rich injection gases. • For Field A reservoir fluid, viscosity of the remaining flashed liquid will increase at pressures below ~2500psi due to mixing the reservoir fluid with a CO₂-rich injection gas stream. • Comparison of injection gases showed that methane rich gases are miscible with Field A so long as a significant quantity of C₃+ components is also present in the gas stream. • There is a defined trend for effect of nC₅ on MMP of impure CO₂. This trend was correlated with an error of less than 4%. • Even though oil composition is taken into account with the base gas MMP, it still affects the trend for effect of nC₅ on MMP of a CO₂-rich gas stream. • An oil characterisation factor was developed to account for this effect, significantly improving the results, reducing the error of the correlation to only 1.6%. The significance of these findings is as follows: • An injection pressure above ~3000psi should be targeted. At these pressures miscibility is achieved and the viscosity of the reservoir fluid injection gas mix is reduced. • CO₂ should be compared to gases such as Tim Gas should after considering the cost of compression, pipeline costs and distance from source to destination will need to be considered. • The addition of nC₅ will reduce the MMP and increase the recovery factor, however the cost of the nC₅ used would be more than the value of increased oil recovered. • The developed correlation for the effect of nC₅ on impure CO₂ MMP can be used broadly within the limits of the correlation. • Further research using more oils is necessary to validate the developed oil characterisation factor and if successful, using the same or similar method used to improve other correlations. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1369016 / Thesis (Ph.D.) -- University of Adelaide, Australian School of Petroleum, 2009.
32

Reading the Street: Iceberg Slim, Donald Goines, and the Rise of Black Pulp Fiction

Nishikawa, Kinohi January 2010 (has links)
<p>"Reading the Street" chronicles the rise of black pulp fiction in the post-civil rights era from the perspective of its urban readership. Black pulp fiction was originally published in the late 1960s and early 1970s; it consisted of paperback novels about tough male characters navigating the pitfalls of urban life. These novels appealed mainly to inner-city readers who felt left out of civil rights' and Black Power's promises of social equality. Despite the historic achievements of the civil rights movement, entrenched structural inequalities led to America's ghettos becoming sites of concentrated poverty, rampant unemployment, and violent crime. While mainstream society seemed to turn a blind eye to how these problems were destroying inner-city communities, readers turned to black pulp fiction for the imaginative resources that would help them reflect on their social reality. In black pulp fiction, readers found confirmation that America was not on the path toward extending equal opportunities to its most vulnerable citizens, or that the rise of Black Power signaled a change in their fortunes. Yet in black pulp fiction readers also found confirmation that their lives as marginalized subjects possessed a value of its own, and that their day-to-day struggles opened up new ways of "being black" amid the blight of the inner city.</p> / Dissertation
33

Efficient Index Structures For Video Databases

Acar, Esra 01 February 2008 (has links) (PDF)
Content-based retrieval of multimedia data has been still an active research area. The efficient retrieval of video data is proven a difficult task for content-based video retrieval systems. In this thesis study, a Content-Based Video Retrieval (CBVR) system that adapts two different index structures, namely Slim-Tree and BitMatrix, for efficiently retrieving videos based on low-level features such as color, texture, shape and motion is presented. The system represents low-level features of video data with MPEG-7 Descriptors extracted from video shots by using MPEG-7 reference software and stored in a native XML database. The low-level descriptors used in the study are Color Layout (CL), Dominant Color (DC), Edge Histogram (EH), Region Shape (RS) and Motion Activity (MA). Ordered Weighted Averaging (OWA) operator in Slim-Tree and BitMatrix aggregates these features to find final similarity between any two objects. The system supports three different types of queries: exact match queries, k-NN queries and range queries. The experiments included in this study are in terms of index construction, index update, query response time and retrieval efficiency using ANMRR performance metric and precision/recall scores. The experimental results show that using BitMatrix along with Ordered Weighted Averaging method is superior in content-based video retrieval systems.
34

Efficient index structures for video databases

Acar, Esra 01 February 2008 (has links) (PDF)
Content-based retrieval of multimedia data has been still an active research area. The efficient retrieval of video data is proven a difficult task for content-based video retrieval systems. In this thesis study, a Content-Based Video Retrieval (CBVR) system that adapts two different index structures, namely Slim-Tree and BitMatrix, for efficiently retrieving videos based on low-level features such as color, texture, shape and motion is presented. The system represents low-level features of video data with MPEG-7 Descriptors extracted from video shots by using MPEG-7 reference software and stored in a native XML database. The low-level descriptors used in the study are Color Layout (CL), Dominant Color (DC), Edge Histogram (EH), Region Shape (RS) and Motion Activity (MA). Ordered Weighted Averaging (OWA) operator in Slim-Tree and BitMatrix aggregates these features to find final similarity between any two objects. The system supports three different types of queries: exact match queries, k-NN queries and range queries. The experiments included in this study are in terms of index construction, index update, query response time and retrieval efficiency using ANMRR performance metric and precision/recall scores. The experimental results show that using BitMatrix along with Ordered Weighted Averaging method is superior in content-based video retrieval systems.
35

Modelos numéricos de vigas mistas de aço e concreto pertencentes a sistemas de pisos mistos de pequena altura em situação de incêndio / Numerical modelling of composite slim floor beams in fire

Fábio Martin Rocha 08 March 2012 (has links)
Os pisos mistos de baixa altura caracterizam um sistema estrutural em que há a incorporação, parcial ou completa, do perfil metálico (viga de aço) na laje de concreto, promovendo a redução da altura da seção e, consequentemente, o aumento da altura útil do pavimento. A incorporação do perfil de aço na laje de concreto garante revestimento ao aço contra o fogo, melhorando o desempenho da viga de aço frente às ações do fogo. Com a finalidade de avaliar o desempenho térmico e estrutural desta solução construtiva, foram desenvolvidos modelos numéricos das vigas parcialmente revestidas presentes nesse sistema estrutural em duas etapas distintas: Na primeira é realizada a análise térmica bidimensional no pacote computacional DIANA para a obtenção dos campos térmicos nas seções transversais das vigas em questão e, a partir daí, considerá-los em um processador de cálculo de momentos plásticos resistentes em todo o intervalo de tempo analisado, sendo então possível avaliar a perda da capacidade portante da seção em função do tempo de exposição ao fogo. A segunda etapa consiste na criação de modelos numéricos tridimensionais em elementos finitos no pacote computacional DIANA, com o qual é possível obter o comportamento estrutural da viga mista de aço e concreto quando exposta ao incêndio padrão, considerando então os efeitos relativos à inclusão do gradiente de temperatura tais como a perda das propriedades mecânicas, a expansão e a interação entre os materiais. Tendo em vista as funcionalidades do código computacional DIANA, diversos modelos foram construídos procurando atingir a melhor aproximação com os resultados experimentais apresentados na literatura associados ao menor custo computacional possível. Dessa forma, foram analisados casos com (1) interação parcial e total entre o aço e o concreto e com (2) diferentes modelos constitutivos para os materiais em questão. Por fim, os resultados obtidos com a análise numérica a partir do DIANA são comparados com os do método dos momentos plásticos, que por sua vez, apresentam um custo computacional bastante reduzido / Slim floor frames consists on structural system in which the steel beam is completely or partially inserted in a concrete slab, that is usually used in profiled steel decks systems. The main goal of the slim floor systems is to obtain a minimum height of the composite beam section and, consequently, achieve a higher height of the floor or a lower total height of the building. The partial encasement of the steel beam in the concrete slab provides a thermal protection, improving the behavior of the beam when subjected to fire. In order to evaluate the thermal and structural behavior of the slim floor system, numerical models considering partially encased beams, which can be found in the slim floor structures, were created. The numerical evaluation procedure was divided in two steps. In the first step, a two-dimensional thermal analysis is carried out using the general finite-element software TNO DIANA to obtain the temperatures gradient in the cross section during the fire exposure time and then, use the data in a computational code developed in FORTRAN which calculates the bearing capacity, over the exposure time, of the slim floor beams by means of the plastic moment capacity method, using the reduction factors associated to the mechanical properties of the materials presented in Eurocode 4. The second step consists in to develop three-dimensional numerical models using the software TNO DIANA and then obtain the complete structural behavior of the beam when subjected to a fire condition. Another aspect related to the loss of mechanical properties was also considered, such as the thermal expansion and the interaction between the steel and the concrete. In view of the DIANA functions, several models were developed in order to achieve a better approximation, a low computational cost, of some tests results presented in wide world literature. The cases of partial and complete interaction between the materials were analyzed, as well as the different constitutive models for them, so that the results obtained at the two steps were compared, and an evaluation of the methods was done
36

Estudo teórico-experimental da contribuição da armadura para a capacidade resistente de vigas parcialmente revestidas / A theoretical and experimental study of steel bars contribution of the bending capacity of the partially encased composite beams

Leandro de Amorim Cavalcanti 26 March 2010 (has links)
Este trabalho tem por objetivo investigar a contribuição da armadura para a capacidade resistente de vigas mistas parcialmente revestidas, bem como sua eficiência para promover o comportamento conjunto aço-concreto, imprescindível para a obtenção de vigas mistas. O estudo engloba uma investigação experimental com ensaios de vigas sob flexão em quatro pontos e uma simulação numérica utilizando o pacote computacional DIANA®, visando obter dados do comportamento de vigas mistas parcialmente revestidas com armadura longitudinal. Foram ensaiados quatro modelos de viga mista parcialmente revestida e duas variáveis foram analisadas: taxa de armadura longitudinal no concreto e posição dos conectores tipo pino com cabeça. Os resultados experimentais mostraram a eficiência do conjunto armadura-conector para o aumento da capacidade resistente à flexão e para a promoção da interação aço-concreto. A simulação numérica teve concordância satisfatória com os resultados experimentais obtidos. / This study aims to investigate the contribution of the steel bars to the flexure capacity and to promote the composite behavior in partially encased composite beams. The study includes an experimental investigation of partially encased beams under bending in four points and a numerical simulation using the computer package DIANA® to collect data from the behavior of partially encased composite beams with longitudinal reinforcement. Four models of partially encased composite beams were tested and two variables were analyzed: rate of longitudinal reinforcement in concrete and position of stud bolts. The experimental results showed the efficiency of the junction between reinforcing bars and stud bolt to the increase the bending capacity of the partially encased beam and to obtain the steel-concrete interaction. The numerical simulation has good agreement with the experimental results.
37

Análise teórico-experimental de pisos mistos de pequena altura / Experimental and theorical analysis of composite shallow floors

Juliana Teodoro Friedrich 13 August 2012 (has links)
O piso misto usual é formado pela laje mista, de aço e concreto, apoiada na mesa superior da viga metálica. No piso misto de pequena altura, a laje mista se apoia na mesa inferior da viga, diminuindo assim a altura total do piso. A forma de aço, utilizada nesse sistema, tende a ser três vezes mais alta, que as formas de aço usuais. No Brasil não há uma forma de aço para uso nos sistemas mistos de pequena altura, comercializada. Este estudo trata do desenvolvimento de uma forma de aço trapezoidal para pisos mistos de pequena altura. Foi desenvolvida uma geometria de forma de aço trapezoidal com mossas estampadas nas laterais. Foram realizados ensaios experimentais com modelos de lajes mistas, confeccionados com a forma de aço desenvolvida no presente estudo. Esses ensaios visaram avaliar a resistência e o comportamento de lajes mistas fabricadas com a forma desenvolvida. A geometria da forma de aço e das mossas apresentaram um bom comportamento frente aos esforços cisalhantes, com resistências comparáveis as formas de aço comercializadas, mostrando que podem ser utilizadas em trabalhos futuros. / The usual composite floor is formed by the composite slab, of steel and concrete, supported on the top flange of the steel beam. On the shallow floor systems, the steel beams are contained within the depth occupied by the floor. The steel form steel used in this composite shallow floor systems is around three times higher than usual forms of steel decking. In Brazil there is not a form of steel for use in shallow floor systems, marketed. This study concerns the development of a steel decking to shallow floor systems. Developed a geometry shape of trapezoidal steel and embossements on the sides. Experimental tests were conducted with composite slabs, made of steel the shape developed in this study. These tests were intended to assess the strength and behavior of composite slabs made with the developed form. The geometry of the steel form and embossements showed good behavior against shearing efforts, forms with resistances comparable steel deckings marketed, showing that may be used in future work.
38

Uma abordagem prática e eficiente de consultas por similaridade para suporte a diagnóstico por imagens. / A pratical and eficient approach of searches for similarity to support diagnose by images.

Natália Abdala Rosa 26 September 2002 (has links)
O objetivo desse trabalho é apresentar as características de um Sistema de Apoio ao Diagnóstico em Sistema Hospitalar Suportando Busca por Imagens Similares, a ser desenvolvido e implantado no Hospital das Clínicas de Ribeirão Preto. A recuperação de imagens baseada no conteúdo é uma área de pesquisa que tem evoluído bastante nos últimos anos. Assim, um sistema de busca e obtenção de imagens, utilizando tal técnica, deve ser extensível aos novos algoritmos de extração de características e métodos de indexação. A extração de características de imagens, tais como informações de cor, textura, forma e o relacionamento entre elas são utilizadas para descrever o conteúdo das imagens. Essas características são então utilizadas para indexar e possibilitar a comparação de imagens no processo de recuperação. O sistema proposto utilizará um método de indexação de dados recém-desenvolvido – a Slim-tree – para indexar as características extraídas das imagens. Através desse método o Sistema de Apoio ao Diagnóstico possibilitará a consulta por conteúdo em imagens médicas. / This works presents the main characteristics of a diagnosis support system based on image similarity search for medical applications. This system was developed to be used in the Clinical Hospital of Ribeirao Preto of the University of Sao Paulo. The content-based image retrieval (CBIR) researching area has evolved greatly in the last years. Thus, a CBIR system should be able to incorporate the new techniques developed, such as, new feature extraction algorithms and indexing methods among others. Traditionally, the main features extracted from images to get the image essence are color, texture, shape and the relationship among them. Therefore, such features describe the images under analysis, and are used to index and to compare images during the content-based retrieval process. The proposed system takes advantage of a new metric access method - the Slim-tree, which allows the indexing and the retrieval of the images through their extracted features.
39

Reengineering skladového systému prodejce sportovního vybavení / Sports Equipment Retailer Storage System Reeingeneering

Sváček, Radim January 2017 (has links)
Goal of this thesis is to analyze processes in company’s warehouse, optimize it and create backend of warehouse’s information system. Application aim to evidence income goods, stock and expedition. System allows comunicate with web services of delivery companies. It was implemented in PHP with use of Nete, Slim and Doctrine. Application was successfuly implemented and tested.
40

Análisis experimental del comportamiento frente a altas temperaturas de vigas planas mixtas de acero-hormigón con materiales avanzados

Serra Mercé, Enrique 04 November 2021 (has links)
[EN] Composite steel-concrete beams embedded in the slab (slim-floor) are being increasingly used worldwide in new residential industrial and commercial building projects, as well as in unique infrastructures. However, the current standard design codes applicable in Europe, present several shortcomings. One of the most significant limitations is related to the calculation under fire exposure, where there is a lack of clear design guidance. In addition, many high-performance steels are beginning to be commercialized internationally. The use of these steels, in combination with the use of lightweight concrete with lower thermal conductivity, may significantly increase the fire resistance of this type of beams without the need of using an external protection, hence reducing the carbon footprint at the same time. This thesis suggests the use of a particular section typology (HEB + welded bottom plate) that improves the safety of the current composite beam systems, allowing for different types of steels to be arranged in the section. Plain carbon steels (S275 or S355) can be used for the main profile, while the high-performance steels (HSS or SS) would be employed only on the lower part of the beam. This will allow to balance out the problem of loss of resistance that these beams present when exposed to elevated temperatures, while reducing their cost. To this aim, a first experimental campaign is developed through eight tests, where the distribution of temperatures is analyzed in detail, as the composite beams are being subjected to the action of fire. Subsequently, an innovative solution, originated during the study of the results of this first group of experiments, is produced. This innovation is based on the insertion of an insulating material in the gap generated between the steel profile and the bottom plate (patent P201930438). To prove its novelty, a second and more reduced experimental campaign was developed. It can be concluded that some of the composite beams configured in this thesis are more sustainable, innovative, and provide competitive solutions for residential, industrial or commercial buildings. The use of new materials in embedded steel profiles is proposed in this thesis, as an alternative to the use of classical fire protection solutions (intumescent coatings or sprayed mortars), providing a solution with a better external finish and without the need for maintenance during its service life, which results in the reduction of the associated environmental impact. / [ES] Las vigas mixtas de acero y hormigón embebidas en el forjado, slim-floor, están siendo cada vez más utilizadas a nivel internacional en las nuevas propuestas de edificación tanto residencial, industrial o comercial, así como en infraestructuras singulares. Sin embargo, los códigos de diseño actuales aplicables en Europa, presentan algunas carencias. Una de las más importantes es respecto a su diseño para resistencia al fuego, para el que no existe una guía clara. Por otra parte, algunos aceros especiales, como los aceros inoxidables (SS) o de alta resistencia (HSS), están empezando a comercializarse a nivel internacional. El empleo de estos aceros, en combinación con la utilización de hormigones ligeros de menor difusividad térmica, puede llegar a incrementar significativamente la resistencia frente al fuego de este tipo de vigas sin necesidad de utilizar una protección externa, reduciendo así, a la vez, la huella de carbono. En esta tesis se sugiere la utilización de una tipología particular de sección (HEB + chapa inferior soldada) que mejora la seguridad de los sistemas de viga mixta actuales, permitiendo disponer diferentes tipos de aceros en la sección. Pueden utilizarse aceros normales (S275 o S355) en el perfil principal, mientras que los aceros de altas prestaciones se dispondrían preferentemente en la parte inferior de la sección. Esto permitiría contrarrestar los problemas de pérdida de resistencia frente a altas temperaturas que presentan estas vigas, reduciendo a la vez su coste. Para ello, se desarrolla una campaña de experimentos con ocho ensayos, donde se analiza en detalle la distribución de temperaturas cuando se somete a las vigas mixtas a la acción del fuego. Posteriormente, se presenta una solución innovadora originada durante el estudio de los resultados de los primeros experimentos, que consiste en la interposición de un material de aislamiento térmico en el hueco generado entre el perfil de acero y la chapa inferior (patente P201930438). Para demostrar su novedad, se desarrolla una segunda campaña de ensayos, más reducida. Se puede concluir que las vigas mixtas que se plantean en la presente tesis son soluciones sostenibles, innovadoras y competitivas para edificación residencial, industrial o comercial. El uso de perfiles de acero embebidos propuesto en esta tesis se plantea como una alternativa frente al empleo de soluciones clásicas de protección pasiva (pinturas intumescentes o morteros de proyección), proporcionando una solución con un mejor acabado externo y sin necesidad de mantenimiento durante su vida en servicio, lo cual redunda en la reducción del impacto ambiental asociado. / [CAT] Les bigues mixtes acer-formigó embegudes en el forjat, slim-floor, són cada vegada més utilitzades a nivell internacional en les noves propostes d'edificació tant residencial, industrial, comercial, com d'infraestructures singulars. No obstant això, els codis de disseny actuals aplicables a Europa, presenten diverses manques. Una de les més importants és respecte al dimensionament enfront el foc, on no existeix una guia de disseny clara D'altra banda, la utilització d'acers especials, com els acers inoxidables (SS) o d'alta resistència (HSS) estan començant a comercialitzar-se a nivell internacional. L'ús d'aquests acers en combinació amb la utilització de formigons lleugers de menor conductivitat, pot arribar a incrementar significativament la resistència al foc d'aquest tipus de bigues sense la necessitat d'utilitzar protecció externa, reduint alhora la petjada de carboni. En aquesta tesi es proposa la utilització d'una tipologia de secció mixta (HEB + xapa inferior soldada) que millora la seguretat dels sistemes actuals, permetent disposar diferents tipus d'acers en la secció, els acers comuns (S275 o S355) en el perfil principal i els acers especials només en la part inferior. Això permetria contrarestar els problemes de pèrdua de resistència enfront d'altes temperatures que presenten aquestes bigues reduint alhora el seu cost. Per a això es desenvolupa una campanya experimental amb huit assajos on s'analitza detalladament la distribució de temperatures sota l'acció del foc. Posteriorment, es presenta una solució innovadora originada durant l'estudi dels resultats de la primera campanya experimental i que consisteix en la interposició d'un material protector en el buit generat entre el perfil i la xapa d'acer (patent P201930438). Per a demostrar la seua novetat, es desenvolupa una segona campanya experimental més reduïda. Es pot concloure que, les bigues mixtes que es plantegen en el present projecte són solucions sostenibles, innovadores i competitives per a edificació residencial, industrial o comercial. L'ús de perfils d'acer embeguts proposat en aquesta tesi es planteja com una alternativa enfront de l'ús de solucions clàssiques (pintures intumescents o morters de projecció), proporcionant una solució amb un millor acabat extern i sense necessitat de manteniment durant la seua vida en servei, la qual cosa redunda en la reducció de l'impacte ambiental associat. / Serra Mercé, E. (2021). Análisis experimental del comportamiento frente a altas temperaturas de vigas planas mixtas de acero-hormigón con materiales avanzados [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/176062 / TESIS

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