<p>In the first part of this thesis, the FE program MSC.Marc is applied for coupled thermomechanical simulations of wire-rod rolling. In order to predict material behaviour of an AISI 302 stainless steel at high strain rates generated during wire-rod rolling, a material model based on dislocation density is applied. Then, the evolution of temperature, strain rate and flow stress is predicted in the first four rolling passes of a wire block.</p><p>In the second part of the thesis, an alternative approach to simulation of shape rolling is evaluated. The approach is applied in order to save the computational time in cases where many shape-rolling passes are to be simulated. The approach is a combination of the slab method and a 2D FEM with a generalized plane-strain formulation. A number of various isothermal shape-rolling passes are simulated applying the simplified approach. The simulations are carried out using an in-house 2D FE code implemented in Matlab. The results are compared to fully 3D FE analyses. The comparison shows that the simplified approach can predict roll forces and roll torques with a fair accuracy, but the predicted area reductions are a bit underestimated. The reasons for the deviations between the simplified approach and the 3D FEM are discussed.</p>

<p>Very often defects are present in rolled products. For wire rods, defects are very deleterious since the wire rods are generally used directly in various applications. For this reason, the market nowadays requires wire rods to be completely defect-free. Any wire with defects must be rejected as scrap which is very costly for the production mill. Thus, it is very important to study the formation and evolution of defects during wire rod rolling in order to better understand and minimize the problem, at the same time improving quality of the wire rods and reducing production costs.</p><p>The present work is focused on the evolution of artificial defects during rolling. Longitudinal surface defects are studied during shape rolling of an AISI M2 high speed steel and a longitudinal central inner defect is studied in an AISI 304L austenitic stainless steel during ultra-high-speed wire rod rolling. Experimental studies are carried out by rolling short rods prepared with arteficial defects. The evolution of the defects is characterised and compared to numerical analyses. The comparison shows that surface defects generally reduce quicker in the experiments than predicted by the simulations whereas a good agreement is generally obtained for the central defect.</p>

Turbulent flows and coherent structures emerging within turbulent flow fields have been extensively studied for the past few decades and a wide variety of experimental and numerical techniques have been developed for measurement and analysis of turbulent flows. The complex nature of turbulence requires methods that can accurately estimate its highly chaotic spatial and temporal behavior. Some of the classical cases of turbulent flows with simpler geometries have been well characterized by means of the existing experimental techniques and numerical models. Nevertheless, since most turbulent fields are of complex geometries; there is an increasing interest in the study of turbulent flows through models with more complicated geometries. In this dissertation, characteristics of turbulent flows through two different facilities with complex geometries are studied applying two different experimental methods. The first study involves the investigation of turbulent impinging jets through a staggered array of rods with or without crossflow. Such flows are crucial in various engineering disciplines. This experiment aimed at modeling the coolant flow behavior and mixing phenomena within the lower plenum of a Very High Temperature Reactor (VHTR). Dynamic Particle Image Velocimetry (PIV) and Matched Index of Refraction (MIR) techniques were applied to acquire the turbulent velocity fields within the model. Some key flow features that may significantly enhance the flow mixing within the test section or actively affect some of the structural components were identified in the velocity fields. The evolution of coherent structures within the flow field is further investigated using a Snapshot Proper Orthogonal Decomposition (POD) technique. Furthermore, a comparative POD method is proposed and successfully implemented for identification of the smaller but highly influential coherent structures which may not be captured in the full-field POD analysis. The second experimental study portrays the coolant flow through the core of an annular pebble bed VHTR. The complex geometry of the core and the highly turbulent nature of the coolant flow passing through the gaps of fuel pebbles make this case quite challenging. In this experiment, a high frequency Hot Wire Anemometry (HWA) system is applied for velocity measurements and investigation of the bypass flow phenomena within the near wall gaps of the core. The velocity profiles within the gaps verify the presence of an area of increased velocity close to the outer reflector wall; however, the characteristics of the coolant flow profile is highly dependent on the gap geometry and to a less extent on the Reynolds number of the flow. The time histories of the velocity are further analyzed using a Power Spectra Density (PSD) technique to acquire information about the energy content and energy transfer between eddies of different sizes at each point within the gaps.

Different wave power technologies are in development around the world in different stages of prototype testing. So far only a few devices have been deployed offshore at full scale for extended periods of time. Little data is published about how these different devices perform. This thesis presents results from experiments with the full-scale offshore wave energy converters at the Lysekil research site on the Swedish west coast. The theories, experiments, measurements, performance evaluations and developments of the submerged transmission in the direct driven permanent magnet linear generator are in focus. The reciprocating submerged transmission fulfills the purpose of transmitting the absorbed mechanical wave energy through the capsule wall into the generator, while preventing the seawater from entering the capsule and reducing the life time of the converter. A measuring system with seven laser triangulation sensors has been developed to measure small relative displacements between piston rod and seal housing in the submerged transmission with excellent accuracy for the purpose of evaluating both functional behavior and successive wear in-situ. A method for calculating relative tilt angles, azimuth angles, differential tilt angles, and successive wear in the submerged transmission has been developed. Additional sensors systems have been installed in the converter enabling correlation and a thorough investigation into the operating conditions of the transmission and the converter. The thesis presents unique results from the measurements. A data acquisition system transmits the signals from the converter on the seabed to an onshore measuring station. Results are presented in time-, frequency- and the time-frequency domain. The results have given important information for further development of the submerged transmission, which is important to the survivability of the system. The thesis describes the status of research, and is a step that may influence future designs of wave energy devices for reaching survivability and a cost-effective renewable energy system. / <p>Published is a preprint version of the full text and should be combined by the errata.</p> / The Lysekil Wave Power Project

Top screw pullout is a significant problem in anterior scoliosis correction, with rates of 5-15% reported in the literature. The Mater Misericordiae Hospital in Brisbane currently has a series of 125 patients with scoliosis treated by thoracoscopic anterior fusion, instrumentation and correction between April 2000 and August 2007. In this series 11 top screws are known to have pulled out (a rate of 8.8%), with six occurring in the first week, and all within 6 weeks, suggesting that the problem is one of excessive static force rather than fatigue. This thesis describes a biomechanical investigation into the mechanics of vertebral body screw pullout in anterior scoliosis surgical constructs. Previous biomechanical studies of vertebral body screws have evaluated their resistance to either straight pullout or cephalo-caudad compression forces, however the aim of this study was to assess screw resistance to more realistic loading conditions, namely pullout of initially angled screws, and pullout where the motion path is an arc rather than a straight axial pullout, as would be expected in a single rod anterior construct. The first series of experiments involved straight and angled pullout tests using synthetic bone. In the angled tests, both locked and free-to-pivot configurations were tested. The second series of experiments tested the effect of cephalo-caudad pre-compression (the actual deformity correction step performed during surgery) on subsequent axial pullout strength. A third series of experiments performed arc pullouts using synthetic bone, and the final series of experiments tested the pullout resistance of a newly proposed screw position configuration against the standard screw positioning using ovine lumbar vertebrae. Synthetic bone testing revealed that for initially angled pullout, resistance is greatest as the screw angle approaches 0 (ie a direct axial pullout). Cephalo-caudad pre-compression reduced subsequent pullout strength for cases where a staple was not used under the screw head, but if a staple was used the pre-compression did not decrease pullout force significantly. Arc pullout resistance was greatest when the screw was angled at 10 cephalad, and the mean pullout strength for the proposed screw configuration using ovine lumbar vertebrae (1864N) was almost double that of the standard screw positioning (993N). The clinical implication of this study is that top screw pullout resistance can be maximised by placing the top screw as close as possible to the top endplate and the bottom screw as close as possible to the bottom endplate, although this will have detrimental effects on the pullout of the second screw should the top screw pull out. Screw angulation is a less important factor but any angulation should be in a cephalad direction and around 10º in magnitude. The experimental results also suggest that the use of a staple may play a role in preventing cephalo-caudad pre-compression forces from reducing screw resistance to subsequent pullout forces.

Made available in DSpace on 2014-12-17T15:47:52Z (GMT). No. of bitstreams: 1 CassioHF_DISSERT.pdf: 1503543 bytes, checksum: f8c5d434affbf0ef65dde0a97d3eb071 (MD5) Previous issue date: 2010-02-22 / Despite the emergence of other forms of artificial lift, sucker rod pumping systems remains hegemonic because of its flexibility of operation and lower investment cost compared to other lifting techniques developed. A successful rod pumping sizing necessarily passes through the supply of estimated flow and the controlled wear of pumping equipment used in the mounted configuration. However, the mediation of these elements is particularly challenging, especially for most designers dealing with this work, which still lack the experience needed to get good projects pumping in time. Even with the existence of various computer applications on the market in order to facilitate this task, they must face a grueling process of trial and error until you get the most appropriate combination of equipment for installation in the well. This thesis proposes the creation of an expert system in the design of sucker rod pumping systems. Its mission is to guide a petroleum engineer in the task of selecting a range of equipment appropriate to the context provided by the characteristics of the oil that will be raised to the surface. Features such as the level of gas separation, presence of corrosive elements, possibility of production of sand and waxing are taken into account in selecting the pumping unit, sucker-rod strings and subsurface pump and their operation mode. It is able to approximate the inferente process in the way of human reasoning, which leads to results closer to those obtained by a specialist. For this, their production rules were based on the theory of fuzzy sets, able to model vague concepts typically present in human reasoning. The calculations of operating parameters of the pumping system are made by the API RP 11L method. Based on information input, the system is able to return to the user a set of pumping configurations that meet a given design flow, but without subjecting the selected equipment to an effort beyond that which can bear / Apesar do surgimento de outras t?cnicas de eleva??o artificial de petr?leo, sistemas de bombeio mec?nico mant?m-se hegem?nicos devido ? sua flexibilidade de atua??o e custo menor de investimento se comparada com outras t?cnicas de eleva??o desenvolvidas. Um dimensionamento de bombeio mec?nico bem sucedido necessariamente passa pelo atendimento da vaz?o prevista e pelo desgaste controlado dos equipamentos de bombeio utilizados na configura??o montada. Entretanto, a concilia??o destes elementos mostrase particularmente desafiadora, sobretudo para a maioria dos projetistas que lidam com este trabalho, que n?o possuem ainda a experi?ncia necess?ria para chegar a bons projetos de bombeio em tempo h?bil. Mesmo com a exist?ncia de diversos aplicativos computacionais no mercado com o objetivo de facilitar esta tarefa, eles precisam enfrentar um exaustivo processo de tentativa e erro at? chegar a combina??o mais adequada de equipamentos para instala??o no po?o. A proposta do presente trabalho consiste em desenvolver um sistema especialista no dimensionamento de sistemas de bombeio mec?nico. Ele tem a miss?o de guiar um engenheiro de petr?leo na tarefa de selecionar um conjunto de equipamentos apropriados ao contexto provido pelas caracter?sticas do ?leo que ser? produzido. Caracter?sticas como o n?vel de separa??o do g?s, presen?a de elementos corrosivos, possibilidade de produ??o de areia e de parafina??o s?o levados em considera??o na escolha da bomba de fundo, coluna de hastes e unidade de bombeio, bem como as caracter?sticas de opera??o dos mesmos. Ele ? capaz de aproximar seu processo de infer?ncia da forma do racioc?nio humano, o que gera resultados mais pr?ximos daqueles obtidos por um especialista. Para tanto, suas regras de produ??o foram elaboradas com base na teoria dos conjuntos fuzzy, capazes de modelar conceitos imprecisos tipicamente presentes no racioc?nio humano. Os c?lculos dos par?metros operacionais do sistema de bombeio s?o feitos por meio do m?todo API RP 11L. Com base em informa??es de entrada, o sistema ? capaz de retornar ao usu?rio um conjunto de configura??es de bombeio mec?nico que atendam uma determinada vaz?o de projeto, por?m sem submeter os equipamentos selecionados a um esfor?o al?m daquele que possam suportar

Made available in DSpace on 2014-12-17T15:48:02Z (GMT). No. of bitstreams: 1 MatheusAS_DISSERT.pdf: 2078765 bytes, checksum: 519489af2ea8e5db40a4abaa98e99b28 (MD5) Previous issue date: 2010-11-18 / With the increase of processing ability, storage and several kinds of communication existing such as Bluetooth, infrared, wireless networks, etc.., mobile devices are no longer only devices with specific function and have become tools with various functionalities. In the business field, the benefits that these kinds of devices can offer are considerable, because the portability allows tasks that previously could only be performed within the work environment, can be performed anywhere. In the context of oil exploration companies, mobile applications allow quick actions could be taken by petroleum engineers and technicians, using their mobile devices to avoid potential catastrophes like an unexpected stop or break of important equipment. In general, the configuration of equipment for oil extraction is performed on the work environment using computer systems in desktop platforms. After the obtained configuration, an employee goes to equipment to be configured and perform the modifications obtained on the use desktop system. This management process equipment for oil extraction takes long time and does not guarantee the maintenance in time to avoid problems. With the use of mobile devices, management and maintenance of equipment for oil extraction can be performed in a more agile time once it enables the engineer or technician oil can perform this configuration at the time and place where the request comes for example, near in the oil well where the equipment is located. The wide variety of mobile devices creates a big difficulty in developing mobile applications, since for one application can function in several types of devices, the application must be changed for each specific type of device, which makes the development quite costly. This paper defines and implements a software product line for designing sucker-rod pumping systems on mobile devices. This product line of software, called BMMobile, aims to produce products that are capable of performing calculations to determine the possible configurations for the equipment in the design suckerrod pumping, and managing the variabilities of the various products that can be generated. Besides, this work performs two evaluations. The first evaluation will verify the consistency of the products produced by the software product line. The second evaluation will verify the reuse of some products generated by SPL developed / Com o aumento da capacidade de processamento, armazenamento e a variedade de tipos de comunica??o existentes, como Bluetooth, infravermelho, redes sem fio, etc., os dispositivos m?veis deixaram de ser apenas dispositivos com fun??o especifica e passaram a ser ferramentas com diversos tipos de funcionalidade. No campo empresarial os benef?cios que estes tipos de dispositivos oferecem s?o consider?veis, uma vez que a portabilidade permite que tarefas que antes s? poderiam ser executadas dentro do ambiente de trabalho, possam ser realizadas em qualquer lugar. No contexto de empresas de explora??o de petr?leo, aplica??es m?veis permitem que a??es r?pidas possam ser tomadas por engenheiros e t?cnicos de petr?leo, usando seus dispositivos m?veis, de forma a evitar poss?veis cat?strofes como a parada de um po?o ou quebra de um equipamento importante. Em geral, a configura??o de equipamentos para extra??o de petr?leo ? realizada no ambiente de trabalho usando sistemas computacionais em plataformas desktop. Ap?s a configura??o ser determinada, algum funcion?rio deve ir ao equipamento a ser configurado e executar as modifica??es obtidas na utiliza??o do sistema desktop. Este processo de gerenciamento de equipamentos para a extra??o de petr?leo demanda muito tempo e n?o garante a manuten??o em tempo h?bil de forma a evitar maiores problemas. Com a utiliza??o de dispositivos m?veis, o gerenciamento e manuten??o de equipamentos para extra??o de petr?leo pode ser realizada de forma mais ?gil, uma vez que permite que o engenheiro ou t?cnico de petr?leo possa realizar essa configura??o no momento e local aonde chega a solicita??o, por exemplo, pr?ximo ao po?o onde est? localizado o equipamento. A grande variedade de tipos de dispositivos m?veis gera uma grande dificuldade no desenvolvimento de aplica??es m?veis, uma vez que para que uma aplica??o possa funcionar em diversos tipos de dispositivos, a aplica??o deve sofrer altera??es para cada tipo especifico de aparelho, o que torna o desenvolvimento bastante custoso. Este trabalho define e implementa uma linha de produto de software para dimensionamento de bombeio mec?nico em dispositivos m?veis. Esta linha de produto de software, denominada BMMobile, tem como objetivo gerar produtos que sejam capazes de realizar c?lculos para determinar as configura??es poss?veis para os equipamentos no dimensionamento de bombeio mec?nico, al?m de gerenciar as variabilidades dos diversos produtos que podem ser gerados. Al?m disso, esse trabalho realiza duas avalia??es. A primeira avalia??o permite verificar a consist?ncia dos produtos produzidos pela linha de produto de software. A segunda avalia??o permite avaliar o reuso em alguns produtos gerados pela LPS desenvolvida

Made available in DSpace on 2014-12-17T14:08:33Z (GMT). No. of bitstreams: 1 HeitorPG.pdf: 2527761 bytes, checksum: 19f772cea6bcb648ba6562ac9a4eeffd (MD5) Previous issue date: 2009-06-26 / The artificial lifting of oil is needed when the pressure of the reservoir is not high enough so that the fluid contained in it can reach the surface spontaneously. Thus the increase in energy supplies artificial or additional fluid integral to the well to come to the surface. The rod pump is the artificial lift method most used in the world and the dynamometer card (surface and down-hole) is the best tool for the analysis of a well equipped with such method. A computational method using Artificial Neural Networks MLP was and developed using pre-established patterns, based on its geometry, the downhole card are used for training the network and then the network provides the knowledge for classification of new cards, allows the fails diagnose in the system and operation conditions of the lifting system. These routines could be integrated to a supervisory system that collects the cards to be analyzed / A necessidade da eleva??o artificial de petr?leo se d? quando a press?o do reservat?rio n?o ? suficientemente elevada para que os fluidos nele contidos possam alcan?ar a superf?cie espontaneamente. Assim a eleva??o artificial fornece energia de forma suplementar ou integral aos fluidos do po?o para que cheguem ? superf?cie. O Bombeio mec?nico com hastes ? o m?todo de eleva??o artificial mais utilizado no mundo e a Carta Dinamom?trica (de superf?cie e de fundo) ? a melhor ferramenta de an?lise de um po?o equipado com esse tipo de m?todo de eleva??o.Um Sistema que utiliza Redes Neurais Artificiais MLP foi desenvolvido e usando padr?es pr?-estabelecidos, baseadas em sua geometria, as cartas de fundo dos po?os s?o utilizadas para o treinamento da rede e posteriormente essa rede disponibiliza o conhecimento adquirido para a classifica??o de novas cartas, permitindo o diagn?stico de poss?veis falhas no sistema de bombeio e das condi??es de funcionamento desse sistema de eleva??o. Essas rotinas podem ser integradas a um Sistema Supervis?rio que coleta as cartas a serem analisadas. Palavras-chave: Automa??o industrial, Eleva??o artificial, Bombeio mec?nico, Redes Neurais

[pt] Um sistema térmico de armazenamento da energia com pasta de cristais de gelo foi desenvolvido para aplicações de condicionamento de ar e resfriamento de processos. O sistema usa um evaporador orbital de haste, um trocador de calor vertical do tipo tubo e carcaça com intensificação mecânica de transferência de calor. A pasta de gelo é produzida continuamente sem acumulação no evaporador e é compatível com unidades condensadoras convencionais, tanques de armazenamento e bombas. Soluções aquosas diluídas ou soluções inorgânicas de salmoura promovem a formação de cristais de gelo, e o gelo líquido resultante pode ser bombeado ou por gravidade alimentar um tanque de armazenamento. O circuito hidráulico de refrigeração (carga térmica) pode ser desacoplado da produção do gelo utilizando-se o tanque de armazenamento. O armazenamento de gelo líquido fornece temperaturas consistentemente baixas à medida que se derrete o gelo, que por sua forma pode ser derretido também muito rapidamente. Com suas altas temperaturas características de evaporação e elevados fluxos do calor, os sistemas de geração de gelo líquido apresentam potencial para reduzir significativamente os custos de capital inicial e operação, quando comparados com tecnologias de sistemas estáticos de gelo ou ice harvesting. / [en] New ice crystal slurry thermal energy storage (TES) system has been developed for both HVAC and process cooling applications. The system uses an orbital rod evaporator (ORE), a vertical shell-and-tube heat exchanger with mechanical heat transfer augmentation, as a dynamic ice maker to generate liquid ice. Ice forms continuously without accumulation in the ORE and is compatible with conventional condensing units, storage tanks, and pumps. Dilute glycol or inorganic brine solutions promote formation of ice crystals, and the resulting liquid ice may be pumped or gravity fed to a storage tank. The cooling load circuit can be hydraulically decoupled from ice production at the storage tank. Stored liquid ice provides consistently low solution supply temperatures over significant portions of the ice melt period and may be melted very rapidly. With its characteristic high evaporator temperatures and high heat fluxes, ORE TES systems have the potential for significantly lower capital and operating costs than static ice or ice harvesting technologies.

Progressive rod-cone degeneration (PRCD) is the late form of progressive retinal atrophy (PRA). It is an autosomal recessive hereditary retinal defect. This disease in dogs is consistent with one form of retinitis pigmentosa (RP) in humans. Phenotypic manifestations are identical and it is known to be an identical causal mutation. A study of this defect in dogs could also explain a lot in human medicine. The gene for PRCD was mapped in the region of centromer of the canine chromosome 9 (CFA9). In this thesis, genotyping of 120 dogs of different breeds and age was performed. Most represented a breed of English Cocker Spaniel which is predisposed to the disease. Analysis PRA-PRCD was performed by molecular genetic methods PCR-RFLP and the horizontal agarose electrophoresis. Genotypes were determined on the basis of different fragment lengths. The normal allele was 396 bp in length and the mutated allele had a length of 116 bp. Presence of mutated allele was only detected in 25 heterozygotes carriers which were usually breeds with this predisposition. Frequency of the mutated allele was 10.4 %. In the selected population 20.8 % of heterozygotes were represented. The results of the study show approximately one fifth of the tested dogs are heterozygous carriers. Findings of other studies confirm there are generally more heterozygotes than homozygotes in which the disease is manifested during life. However, if this fact is not clearly taken in consideration, the number of sick dogs can rapidly increase during short period of time. In the future, it would be appropriate to adopt measures which would definitely eliminate the occurrence of the mutated allele. These measures could include genetic tests that reliably reveal hidden carriers (heterozygotes) in predisposing breeds. Heterozygotes may increase the representation of this allele in the population. This leads to an increase in the number of diseased animals.