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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.
361

Možnosti využívání klasických popílků po zavedení SNCR / Possibilities of using classical fly ashes after the introduction of selective non-catalytic reduction

Beranová, Denisa January 2015 (has links)
The master thesis deals with possibilities of utilization of conventional power plant fly ash after introduction of SNCR (Selective non-catalytic reduction) as a method of flue gas denitrification. Behaviour of fly ash containing products of denitrification, ash with water and stabilizate prepared from contaminated ash was studied. Experiments were focused on the study of various factors affecting the release of ammonia from prepared mixtures. Samples were exposed to the weather conditions to simulate deposition in addition to the laboratory experiment. Influence of the fly ash containing denitrification to mechanical properties and volume stability of pastes and mortars were also studied. The interaction of denitrification products with superplasticizers was studied on pastes. Achieved results were verified on concretes.
362

Elaboração de um instrumento de avaliação de segurança em calçadas

Zanini, Camila Mokwa January 2017 (has links)
A falta de controle e planejamento dos espaços públicos, entre eles, as calçadas, gera problemas como a falta de segurança e de acesso aos equipamentos urbanos e até impede a livre circulação das pessoas. As calçadas são uma pequena, mas importante parte da complexa infraestrutura urbana. O provimento de calçadas adequadas é um meio de incentivo ao deslocamento a pé e ao uso de transporte coletivo. A calçada não deveria oferecer nenhum risco aos pedestres, porém, grande parte das calçadas existentes no Brasil é imprópria para a circulação, seja pela existência de obstáculos, seja pela precariedade ou inadequação dos materiais utilizados em sua construção. Essa falta de qualidade das calçadas é a causa de muitos acidentes. Os pedestres em geral e, além dos idosos, principalmente as crianças e as pessoas portadoras de necessidades especiais, podem ser considerados usuários vulneráveis. No presente trabalho, as exigências dos usuários, no que se refere à segurança em uso, de acordo com a abordagem de desempenho, foram identificadas como sendo segurança ao risco de quedas, segurança ao risco de atropelamentos, segurança ao risco de lesões por choque e acessibilidade. As exigências dos usuários foram traduzidas em requisitos de desempenho a serem cumpridos em calçadas seguras e, após, foram identificados os respectivos critérios, níveis de atendimento e métodos de avaliação, com base na legislação e bibliografia. Com isso, foi elaborado um instrumento de avaliação de segurança em calçadas. Um estudo de caso em um trecho da Av. Independência, em Porto Alegre, foi realizado para testar o instrumento elaborado, com aplicação experimental em 17 calçadas. O instrumento mostrou-se eficiente na aquisição, processamento e registro de dados. Para a validação definitiva do instrumento, é necessário que se amplie os testes. Além disso, foi realizada pesquisa exploratória com aplicação do ensaio com o Pêndulo Britânico, para avaliação da resistência ao escorregamento. Todas as calçadas foram aprovadas quanto a este critério. O método de avaliação se mostrou adequado, porém limitado a calçadas com pequena inclinação. Adicionalmente, as diversas falhas relativas à segurança encontradas nas calçadas avaliadas foram analisadas. Nenhuma calçada do estudo de caso foi aprovada e considerada segura. A calçada com pior desempenho atendeu a apenas 38,88% dos critérios. Já o melhor resultado foi de uma calçada com taxa de atendimento aos critérios de 68,42%. Os critérios menos atendidos foram o desnível em relação à via, o rebaixo para acesso de veículos adequado, rampa nos pontos de travessia e a sinalização tátil no piso. Diante da grande quantidade de falhas encontradas no estudo de caso, aponta-se a ausência de um técnico no processo de construção de uma calçada, como uma das principais causas das não conformidades, junto à falta de um documento, preferencialmente uma Norma Técnica, que reúna as informações necessárias para o projeto de calçadas. Desta forma, este trabalho visa contribuir para o tema desempenho de calçadas, com foco nos requisitos relativos à segurança dos usuários. / The absence of control and planning of public spaces, including sidewalks, creates problems such as lack of security and access to urban equipment and even prevents the free movement of people. The sidewalks are a small but important part of the complex urban infrastructure. Providing adequate sidewalks is a means of encouraging walking and the use of public transport. The sidewalk should not pose any risk to pedestrians, but most of the existing sidewalks in Brazil are unfit for circulation, either by the existence of obstacles, or by the precariousness or inadequacy of the materials used in their construction. This lack of quality in sidewalks is the cause of many accidents. Pedestrians in general and, in addition to the elderly, especially children and people with special needs, can be considered vulnerable users. In this work, users' requirements regarding safety in use, according to the performance approach, have been identified as safety for the risk of falls, safety for the risk of pedestrian crashes, safety for the risk of shock injuries and accessibility. The users’ requirements were translated into performance requirements to be met on safe sidewalks and, afterwards, the respective criteria, suitable levels and evaluation methods were identified, based on legislation and bibliography. And therewith, a safety assessment instrument for sidewalks was developed. A case study on an excerpt from Av. Independência, in Porto Alegre, was carried out to test the instrument, with experimental application on 17 sidewalks. The instrument was efficient in data acquisition, processing and recording. For definitive validation of the instrument, it is necessary to expand the tests. In addition, an exploratory study was carried out with the application of the British Pendulum test to evaluate the slip resistance. All sidewalks were approved for this criterion. The method of evaluation was adequate, but limited to sidewalks with a small slope. In addition, the various safety flaws found on the evaluated sidewalks were analyzed. No sidewalk from the case study was approved and considered safe. The sidewalk with the poorest performance met only 38.88% of the criteria. The best result was a sidewalk with a rate of meeting the criteria of 68.42%. The least attended criteria were the height in relation to the roadway, adequate vehicle access ramp, ramp at crossing points and tactile signage on the ground. Considering the large number of flaws found in the case study, it is pointed out that the absence of a technician in the process of building a sidewalk is one of the main causes of nonconformities, due to the lack of a document, preferably a Technical Standard, that gathers the necessary information for sidewalk projects. Thus, this work aims to contribute to the theme of performance of sidewalks, focusing on requirements regarding user safety.
363

La marge Nord du Fossé Basque à l'Albien : architecture sédimentaire et diapirisme dans un contexte décrochant (Pays Basque, Espagne) / The Albian northern margin of the Basque Trough : sedimentary architecture and diapirism in a strike-slip tectonic setting (Basque Country, Spain)

Poprawski, Yohann 27 January 2012 (has links)
L'objectif initial de cette thèse consistait à fournir un analogue de terrain de réservoirs pétroliers avec un modèle 3D des structures et de l'architecture des sédiments développés sur la bordure d'un basin étroit et confiné. La zone d'étude, située entre Bakio et Plenzia (Pays Basque, Espagne), appartient au fossé Basque, souvent interprété comme un basin en pull-apart. Nous avons focalisé ce travail sur le diapir de Bakio, sur les modalités de la montée du sel, sa chronologie et sur l'impact de la tectonique salifère sur sédimentation et la déformation des sédiments environnants. Un éventail sédimentaire composé de dépôts albiens, avec un amincissement vers le diapir montre la monté synsédimentaire du sel. Nous démontré l'existence d'une première phase de montée du sel réactive puis une seconde phase passive. La phase réactive est expliquée par l'extension régionale. Durand le stade passive, des séquences halokinetiques, qui résultent de variations entre la monté du sel et le taux de sédimentation, ont été formées. Nos données montre qu'une grande partie de la déformation est due à la rotation des flancs du diapir et non à un cisaillement significatif induit par la montée su sel. Nous avons aussi concentré ce travail sur les structures albiennes de notre zone d'étude. La comparaison avec l'ensemble du Bassin Basco Cantabrien montre deux stades d'activation des failles. De l'Aptien à l'Albien moyen, les nombreuses failles orientées NE-SO, largement distribuées,contrôlaient les plates formes urgoniennes et les fossés marneux associés. Quelques failles majeures héritées, orientées NO-SE contrôlaient aussi les dépocentres surtout dans la partie centrale du Basin Basco-Cantabrien. Ce premier stage est interprété comme le résultat d'un extension NO-SE. De l'Albien moyen à supérieur, la déformation était localisée essentiellement le long de la faille Guernika-Elgoibar, orientée NO-SE, qui contrôle un bassin asymétriques, étroit et allongé remplis par les Flyschs Noirs. Durant le second stage, les dépocentres du Flysch Noir sont interprétés comme des bassins en transtension et non en pull-apart, car une seule faille majeure contrôlait ces basins asymétriques. / The initial purpose of this thesis was to provide a field analogue for petroleum reservoirs with a 3D model of the main structures and of the architecture of deposits developed on the border of a narrow and confined basin. The study area, located between Bakio and Plenzia (Basque Country, Spain), belongs to the Basque Trough, commonly interpreted as a pull-apart basin. We focused on the Bakio diapir, which allows a discussion of the modalities of salt rising, its chronology and of the impacts of salt on the overburden deformation and on sedimentation. A well exposed wedge-shaped structure composed of Albian deposits, with thinning toward the diapir documents synsedimentary salt rising. We showed that the diapir rose firstly as a reactive diapir in response to regional extension and then as a passive diapir. During the passive stage, halokinetic sequences developed, induced by variations of the ratio between net salt rising and net sedimentation rate. All our data from the Bakio diapir show that an important part of deformation is related to diapir flank rotation and not to significant shear associated with salt rising. We also focused on the Albian structural geology in our study area. The comparison of the local Albian fault system with faults from the whole Basque-Cantabrian Basin emphasizes two stages of faults activity. From Aptian to Early-Middle Albian, widely distributed NE-SW striking faults controlled the development of the Urgonian platforms and associated marly troughs. Some major inherited NW-SE striking faults also controlled the localization of depocenters, especially in the central part of the Basque-Cantabrian Basin. The first stage is assumed to result of a NW-SE extension. From Middle to Late Albian, the deformation localized mainly along the Gernika-Elgoibar fault, striking NW-SE, and controlled the formation of a narrow and elongated asymmetric basin developed, filled by Black Flysch units. During this second stage, Black Flysch depocenter are interpreted to form in transtensional setting and cannot be interpreted as pull-apart basins, as only one major fault controlled asymmetric basins.
364

Suivi temporel de la zone de subduction d'Amérique Centrale et imagerie de la vallée de Mexico / Passive Seismic Monitoring of the Middle America Subduction Zone and Study of the Valley of Mexico

Rivet, Diane 15 February 2012 (has links)
Ces dernières années ont vu le développement d'une nouvelle méthode d'imagerie des structures géologiques basée sur l'utilisation du bruit sismique continu. Dans ce travail nous avons utilisé cette approche dans deux problématiques différentes. La première consiste à réaliser le suivi temporel des vitesses des ondes sismiques dans la croûte lors de séismes lents qui ont eu lieu dans la région de Guerrero au Mexique. Les séismes lents sont des glissements asismiques et transitoires qui ont été découverts récemment dans la lacune sismique de Guerrero. Ils sont considérés comme une part importante de la relaxation des déformations dans le cycle sismique. Les séismes lents affectent le processus de chargement et déchargement de l'interface, il est donc important de comprendre le comportement mécanique de la subduction dans cette région pour mieux évaluer le risque sismique. Dans notre étude, nous avons mesuré les perturbations de vitesse des ondes associées à deux séismes lents en 2006 et 2009-2010 à partir des enregistrements continus du bruit sismique. Pour chacun des deux séismes lents on observe une chute de vitesse : elle s'élève à 0.2% pour celui de 2006 et à 0.8 % pour celui de 2009-2010. Au cours de ces séismes lents, les ondes de longues périodes (>10 s) sont perturbées. A courtes périodes, aucune variation de vitesse n'est observée ce qui suggère qu'un endommagement des couches superficielles de la croûte ne peut pas être à l'origine du changement de vitesse. Par ailleurs, la perturbation de vitesse est reliée au taux de dé- formation plutôt qu'à la déformation elle-même. Cette observation suggère que pendant de forts séismes lents, la croûte chevauchante présente un comportement mécanique non linéaire. Nous pouvons donc utiliser les variations de vitesse comme des marqueurs du taux de déformation du milieu. Enfin, une corrélation entre les trémors non volcaniques et les variations de vitesse suggère qu'une part importante de la déformation résultant des séismes lents est accommodée par la croute chevauchante. La deuxième problématique abordée dans cette thèse est l'imagerie de structures à fort contraste de vitesse et dans lesquelles la propagation des ondes de surface est complexe. Imager et comprendre la propagation des ondes dans la vallée de Mexico est crucial pour l'estimation du risque sismique à la capitale. Nous mesurons la dispersion des ondes de Rayleigh reconstruites à partir d'intercorrélations de bruit de fond sismique. Pour identifier les modes nous utilisons une mesure du rapport spectral des composantes horizontales sur la composante vertical (H/V) sur la coda des séismes que l'on compare avec le rapport H/V théorique. Grâce à cette identification des modes, nous pouvons retrouver le modèle de vitesse de la structure. / Recent years have seen the development of a new method for imaging geological structures based on continuous seismic noise. In this work we used this approach in two different problems. The first is to monitor seismic waves velocity in the crust during slow slip events that occurred in the region of Guerrero in Mexico. These slow slip events are aseismic transients that were observed recently in the seismic gap of Guerrero. They are considered an important part of the strain relaxation in the seismic cycle. Since slow slip events affect the process of loading and unloading of the interface, it is important to understand the mechanical behavior of the subduction in this region to better assess the seismic risk. In our study, we measured wave velocity perturbations associated with two slow slip events in 2006 and 2009-2010 from continuous recordings of seismic noise. For both events we observed a drop in wave speed : it reaches 0.2 % in 2006 and 0.8 % in 2009-2010. During these slow slip events waves of long periods (> 10 s) are disturbed. At short period, no velocity variation is observed suggesting that damage of the superficial layers of the crust cannot produce such velocity perturbation. Moreover, the wave speed change is related to the strain rate rather than the deformation itself. This observation suggests that during strong slow slip events the overriding crust presents a nonlinear mechanical behavior. We can therefore use the velocity variations as a proxy of the strain rate of the medium. Finally, a correlation between non-volcanic tremor and changes in waves speed suggests that part of the deformation resulting from the slow slip events is accommodated by the overriding crust. The second issue addressed in this thesis is imaging geological structures with high velocity contrast in which the propagation of surface waves is complex. Charac- terizing and understanding wave propagation in the Valley of Mexico is crucial for the estimation of seismic risk in Mexico City. We measure the dispersion of Rayleigh waves reconstructed from cross-correlations of seismic noise. To identify the modes of Rayleigh waves we use a measure of the spectral ratio of the horizontal components to the vertical component (H / V) in the coda of earthquakes which are compared with the theoretical H / V. With this identification method, we can find the velocity model of the structure.
365

Analysis laminar flow, thermal stability, and entropy generation in porous channel

Eegunjobi, Adetatayo Samuel January 2013 (has links)
Thesis submitted in fulfillment of the requirements for the degree Doctor of Technology: Mechanical Engineering Cape Peninsula University of Technology, 2013 / Fluid flow through a porous channel and cylindrical pipe walls are important area of research due to its wide applications in transpiration cooling, gaseous diffusion technology, cooling of rocket, mechanized irrigation and filtration processes. It is therefore necessary to examine the effect of Navier slip, combined effects of buoyancy forces and variable viscosity on the entire flow structure. Analyzing the magneto- hydrodynamics (MHD) of unsteady flow with buoyancy effect and also investigate numerically the entropy generation in an unsteady flow through porous pipe. We have also examined the thermal stability and entropy generation in the system. The problems were investigated theoretically using appropriate mathematical models for both transient and steady state scenario. Both analytical techniques and numerical methods are employed to tackle the model nonlinear equations derived from the law of conservation of mass, momentum and energy balance. Some definitions of terms to come across and introduction to fluid flow are given in chapter 1, together with literature reviews, statement of problem and objectives of the study. Chapter 2 lays the foundation for basic fundamental equations governing fluid flow. In chapter 3, the combined effect of suction/injection and asymmetric Navier slip on the entropy generation rate for steady flow of an incompressible viscous fluid through a porous channel subjected to different temperature at the walls are investigated. Chapter 4 analyze combined effects of buoyancy forces together with Navier slip on the entropy generation in a vertical porous channel wall with suction/injection wall. Analysis of MHD unsteady flow through a porous pipe with buoyancy effects are carried out in chapter 5, while chapter 6 investigates numerically entropy generation of unsteady flow through a porous pipe with suction and chapter 7 gives concluding remarks.
366

Controle inteligente de sistemas subatuados com aplica??es em problemas de mec?nica do contato

Fernandes, Josiane Maria de Macedo 28 June 2017 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-10-18T20:27:50Z No. of bitstreams: 1 JosianeMariaDeMacedoFernandes_TESE.pdf: 1245335 bytes, checksum: 5135bc4fc7856839af432f3c4f427beb (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-10-23T22:17:47Z (GMT) No. of bitstreams: 1 JosianeMariaDeMacedoFernandes_TESE.pdf: 1245335 bytes, checksum: 5135bc4fc7856839af432f3c4f427beb (MD5) / Made available in DSpace on 2017-10-23T22:17:47Z (GMT). No. of bitstreams: 1 JosianeMariaDeMacedoFernandes_TESE.pdf: 1245335 bytes, checksum: 5135bc4fc7856839af432f3c4f427beb (MD5) Previous issue date: 2017-06-28 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / Neste trabalho ? desenvolvida uma estrat?gia de controle n?o linear baseada no controle por modos deslizantes com compensa??o neural para estabiliza??o de sistemas subatuados sujeitos a vibra??es torcionais. No intuito de analisar o desempenho da abordagem proposta, a lei de controle foi implementada em uma coluna de perfura??o. As colunas de perfura??o s?o discretizadas em n partes. A atua??o ? dada no top drive, ou na mesa rotativa na extremidade superior da coluna, e todo o restante da coluna n?o recebe atua??o. As vibra??es torcionais abordadas neste trabalho s?o do tipo stick-slip, que ? o caso mais cr?tico desse tipo de vibra??o, cuja n?o linearidade ? geralmente causada pelo atrito entre a coluna e a forma??o, podendo ocorrer em qualquer ponto ao longo da coluna e deve ser levado em considera??o na modelagem. O controle por modos deslizantes apresenta robustez frente a incertezas param?tricas e perturba??es. A estrat?gia adotada n?o requer o conhecimento pr?vio de incertezas e n?o linearidades do sistema. No entanto, a fun??o descont?nua utilizada na lei de controle pode gerar o fen?meno de chattering, que em atuadores mec?nicos ? indesej?vel. Para atenuar o chattering, uma fun??o suave ? utilizada no lugar da descont?nua, sendo essa abordagem ocasionadora de diminui??o no desempenho do controlador. Nesse ponto, t?cnicas de intelig?ncia artificial podem contribuir na lei de controle para devolver o desempenho ou parte dele ao sistema. Duas arquiteturas de rede s?o empregadas para estimar a compensa??o, uma rede do tipo perceptron de m?ltiplas camadas e uma rede de fun??es de base radial. As superf?cies de controle s?o definidas como uma combina??o linear dos erros dos estados do sistema e uma rede neural ? adicionada para compensar a forma??o de ciclos limites, comumente apresentados ap?s a perda de efic?cia. Resultados s?o apresentados para demonstrar a performance do sistema de controle proposto. / In the present work, a nonlinear control strategy based on sliding mode method and artificial neural networks is presented. This approach can be applied to stabilize nonlinear under actuated systems subjected to torsional vibrations. In order to evaluate the proposed approach, the control law was implemented in a drill string. Drill strings are addressed due to their nonlinear and underactuated dynamics. The drill strings are discretized in n parts. The control output is given at the top drive whereas the other string parts are not directly actuated. Torsional vibrations employed in this work are stick-slip, which is the more critic way of torsional vibrations. Stick-slip is a nonlinearity usually caused by friction between the drill string and rock formations and can occurs at any point along its length. Sliding mode control is a very robust technique even with parametric uncertainties and external perturbations. There is no need of previous knowledge of uncertainties and nonlinearities. The discontinuous function adopted at the control law can lead to the undesired chattering effect. The discontinuous function can be replaced by a smooth function to avoid chattering, but this also implies on decrement of the system performance. In order to attenuate this effect, a compensation is added to the control law. Two different artificial neural network architectures are investigated: multilayer perceptrons and radial basis functions. The sliding surfaces are defined as a linear combination of tracking errors. The neural network is employed to mitigate the generated limit cycle. Numerical results are presented in order to demonstrate the performance of the control system.
367

Elaboração de um instrumento de avaliação de segurança em calçadas

Zanini, Camila Mokwa January 2017 (has links)
A falta de controle e planejamento dos espaços públicos, entre eles, as calçadas, gera problemas como a falta de segurança e de acesso aos equipamentos urbanos e até impede a livre circulação das pessoas. As calçadas são uma pequena, mas importante parte da complexa infraestrutura urbana. O provimento de calçadas adequadas é um meio de incentivo ao deslocamento a pé e ao uso de transporte coletivo. A calçada não deveria oferecer nenhum risco aos pedestres, porém, grande parte das calçadas existentes no Brasil é imprópria para a circulação, seja pela existência de obstáculos, seja pela precariedade ou inadequação dos materiais utilizados em sua construção. Essa falta de qualidade das calçadas é a causa de muitos acidentes. Os pedestres em geral e, além dos idosos, principalmente as crianças e as pessoas portadoras de necessidades especiais, podem ser considerados usuários vulneráveis. No presente trabalho, as exigências dos usuários, no que se refere à segurança em uso, de acordo com a abordagem de desempenho, foram identificadas como sendo segurança ao risco de quedas, segurança ao risco de atropelamentos, segurança ao risco de lesões por choque e acessibilidade. As exigências dos usuários foram traduzidas em requisitos de desempenho a serem cumpridos em calçadas seguras e, após, foram identificados os respectivos critérios, níveis de atendimento e métodos de avaliação, com base na legislação e bibliografia. Com isso, foi elaborado um instrumento de avaliação de segurança em calçadas. Um estudo de caso em um trecho da Av. Independência, em Porto Alegre, foi realizado para testar o instrumento elaborado, com aplicação experimental em 17 calçadas. O instrumento mostrou-se eficiente na aquisição, processamento e registro de dados. Para a validação definitiva do instrumento, é necessário que se amplie os testes. Além disso, foi realizada pesquisa exploratória com aplicação do ensaio com o Pêndulo Britânico, para avaliação da resistência ao escorregamento. Todas as calçadas foram aprovadas quanto a este critério. O método de avaliação se mostrou adequado, porém limitado a calçadas com pequena inclinação. Adicionalmente, as diversas falhas relativas à segurança encontradas nas calçadas avaliadas foram analisadas. Nenhuma calçada do estudo de caso foi aprovada e considerada segura. A calçada com pior desempenho atendeu a apenas 38,88% dos critérios. Já o melhor resultado foi de uma calçada com taxa de atendimento aos critérios de 68,42%. Os critérios menos atendidos foram o desnível em relação à via, o rebaixo para acesso de veículos adequado, rampa nos pontos de travessia e a sinalização tátil no piso. Diante da grande quantidade de falhas encontradas no estudo de caso, aponta-se a ausência de um técnico no processo de construção de uma calçada, como uma das principais causas das não conformidades, junto à falta de um documento, preferencialmente uma Norma Técnica, que reúna as informações necessárias para o projeto de calçadas. Desta forma, este trabalho visa contribuir para o tema desempenho de calçadas, com foco nos requisitos relativos à segurança dos usuários. / The absence of control and planning of public spaces, including sidewalks, creates problems such as lack of security and access to urban equipment and even prevents the free movement of people. The sidewalks are a small but important part of the complex urban infrastructure. Providing adequate sidewalks is a means of encouraging walking and the use of public transport. The sidewalk should not pose any risk to pedestrians, but most of the existing sidewalks in Brazil are unfit for circulation, either by the existence of obstacles, or by the precariousness or inadequacy of the materials used in their construction. This lack of quality in sidewalks is the cause of many accidents. Pedestrians in general and, in addition to the elderly, especially children and people with special needs, can be considered vulnerable users. In this work, users' requirements regarding safety in use, according to the performance approach, have been identified as safety for the risk of falls, safety for the risk of pedestrian crashes, safety for the risk of shock injuries and accessibility. The users’ requirements were translated into performance requirements to be met on safe sidewalks and, afterwards, the respective criteria, suitable levels and evaluation methods were identified, based on legislation and bibliography. And therewith, a safety assessment instrument for sidewalks was developed. A case study on an excerpt from Av. Independência, in Porto Alegre, was carried out to test the instrument, with experimental application on 17 sidewalks. The instrument was efficient in data acquisition, processing and recording. For definitive validation of the instrument, it is necessary to expand the tests. In addition, an exploratory study was carried out with the application of the British Pendulum test to evaluate the slip resistance. All sidewalks were approved for this criterion. The method of evaluation was adequate, but limited to sidewalks with a small slope. In addition, the various safety flaws found on the evaluated sidewalks were analyzed. No sidewalk from the case study was approved and considered safe. The sidewalk with the poorest performance met only 38.88% of the criteria. The best result was a sidewalk with a rate of meeting the criteria of 68.42%. The least attended criteria were the height in relation to the roadway, adequate vehicle access ramp, ramp at crossing points and tactile signage on the ground. Considering the large number of flaws found in the case study, it is pointed out that the absence of a technician in the process of building a sidewalk is one of the main causes of nonconformities, due to the lack of a document, preferably a Technical Standard, that gathers the necessary information for sidewalk projects. Thus, this work aims to contribute to the theme of performance of sidewalks, focusing on requirements regarding user safety.
368

Geometry, kinematics, and Quaternary activity of the brittle Leech River fault zone, southern Vancouver Island, British Columbia, Canada

Graham, Audrey 06 February 2018 (has links)
Southern Vancouver Island lies on the forearc of the Cascadia subduction zone, north of a concave bend in the plate boundary centred around the Olympic Mountains. The bend in the margin coincides with a significant decrease in northward-directed trench-parallel forearc migration, and a network of active crustal faults in the Puget Lowland east of the Olympic Mountains accommodates permanent north-south shortening and transpression. The nature of forearc deformation on southern Vancouver Island is less well constrained, due in part to the unknown extent and kinematics of active crustal faulting. Recent work has shown that a brittle fault zone associated with the Eocene terrane-bounding Leech River fault has produced at least two surface-rupturing earthquakes in the late Quaternary. I use LiDAR-derived topographic data, slip-sense indicator analysis of slickenlines on fault planes, electrical resistivity tomography (ERT), and ground-penetrating radar (GPR) to investigate the geometry, kinematics, and Quaternary activity along the eastern half of the active, brittle Leech River fault zone. My mapping reveals a complex, near-vertical zone up to 1 km wide and 25 km long that exhibits many characteristics of a strike-slip fault. Displaced Quaternary deposits are observed directly at two sites in the western 8 km of the study area, and inferred through geophysical imagery, topographic data, and liquefaction features to extend to the eastern terrestrial extent of the fault zone towards previously mapped active faults in the Juan de Fuca Strait and the Darrington-Devil’s Mountain fault zone in western Washington. I use fault kinematics and geometry to show that the eastern Leech River fault zone has been reactivated as a right-lateral strike-slip fault that accommodates forearc deformation within the modern stress field north of the Olympic Mountains. / Graduate / 2018-12-01
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Método dos elementos de contorno aplicado na análise do escorregamento de estacas. / Boundary element method applied in pile slip analysis.

Guilherme Basílio Vick 04 April 2014 (has links)
Neste trabalho apresenta-se um modelo numérico para a análise de problemas tridimensionais envolvendo a interação mecânica estaca-solo, acoplando-se o Método dos Elementos de Contorno (MEC) ao Método dos Elementos Finitos (MEF). O solo é modelado com o MEC utilizando-se as soluções fundamentais de Mindlin, assumindo um meio semi-infinito, homogêneo, isotrópico e elástico-linear. As estacas, modeladas com o MEF, consistem em um elemento único, com quatro nós e 14 parâmetros nodais (três deslocamentos em cada nó e mais duas rotações no topo da estaca). Cada uma das estacas é levada em consideração no MEC como uma linha de carga. Considera-se o escorregamento das estacas em relação ao maciço, empregando modelos de aderência para a definição da evolução das tensões tangenciais ao longo do comprimento das estacas. São empregados, como funções de forma, polinômios do quarto grau para os deslocamentos horizontais, cúbicos para os deslocamentos verticais e tensões horizontais ao longo do fuste e quadráticos para as tensões verticais do fuste e escorregamento. A reação da ponta da estaca é calculada assumindo tensão constante na base. / This work presents a method for tri-dimensional pile-soil interaction problems, by coupling the Boundary Element Method (BEM) to the Finite Element Method (FEM). The soil is modeled with BEM, using the Mindlins fundamental solutions, supposing a semi-infinite, homogeneous, isotropic, elastic and linear space. Piles are modeled with FEM and are represented by one element with four nodes and 14 nodal parameters (three displacements in each node and two rotations at the top node). Each pile is represented in BEM as a line load. The pile slip is considered using adherence models to evaluate the evolution of shaft tractions. There are employed fourth grade polynomial shape functions for horizontal displacements, cubic polynomial functions for vertical displacements and horizontal tractions along shaft and quadratic polynomial functions for vertical tractions and slip. Tip reaction is calculated supposing constant traction at the base.
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Análise comparativa de argamassas colantes de mercado através de parâmetros reológicos. / Comparative analysis of commercial dry-set mortars using rheological parameters.

Marienne do Rocio de Mello Maron da Costa 31 January 2006 (has links)
O presente trabalho propõe o entendimento do comportamento no estado fresco de argamassas colantes, com base na caracterização reológica e físico-química de diferentes composições comerciais, servindo de base para analisar o fenômeno de deslizamento, a partir do ensaio estabelecido na norma brasileira. Para isso, foi utilizado o ensaio “Squeeze flow” (escoamento por compressão axial), empregado na caracterização de argamassas de revestimento no laboratório de microestrutura do CPqDCC da EPUSP, como ferramenta de análise do comportamento de argamassas colantes. Neste ensaio, o escoamento do material decorre da aplicação de uma carga de compressão sobre a amostra no estado fresco, a qual ocasiona deslocamentos no seu interior devido a esforços de cisalhamento radiais originados durante o fluxo. O critério de seleção das argamassas colantes comerciais (tipo AC-I) se baseou nos resultados do ensaio de deslizamento, escolhendo-se duas com resultado muito abaixo do limite especificado, duas com resultado próximo do limite e outras duas com resultado acima do mesmo. A composição química e física foi caracterizada com o objetivo de embasar a análise dos resultados obtidos no “Squeeze flow”. A separação da fração fina das argamassas na peneira no.200 contribuiu para o conhecimento da viscosidade da pasta e da sua influência no comportamento reológico das argamassas. Foi observado que as argamassas estudadas apresentam diferenças de composição físico-química e de comportamento reológico. As diferenças de comportamento reológico das argamassas decorrem, provavelmente, de ação sinérgica de alguns parâmetros da composição, com destaque para a distribuição granulométrica. O “Squeeze flow” mostrou-se uma ferramenta adequada na caracterização das argamassas colantes e contribuiu para explicar o deslizamento estabelecido na norma brasileira, pela proposição de modelos hipotéticos de comportamento. / Present thesis proposes the study of plastic-state behaviour of dry-set mortars based on the rheological and physicochemical characterization of different commercially available dry-set mortar compositions. Such characterization served as basis for the analysis of dry-set mortar slip phenomena using the tests recommended by brazilian standards (NBR). The Squeeze Flow test (slip by axial compression) originally used for coating mortars characterization by the EPUSP CPqDDC Microstructure Laboratory was adopted as a test tool for analysing the dry-set mortar behaviour. In the mentioned test the material slip is obtained by compressing the sample in its plastic state which caused internal displacements due to radial shearing tensions originated during the mentioned slip. The dry-se mortars (all of them AC-I type) used in the study were selected based in the slip tests results against brazilian standards specified limits resulting in the selection of two dry-set mortars below the specified limit, two dry-set mortars close to the specified limit and dry-set mortars above the specified limit. Chemical and physical compositions were characterized in order to serve as basis for Squeeze Flow results analysis. Fine fraction segregation, using number 200 sieve contributed to understanding of plastic-state mortar viscosity and its influence in mortar rheological behaviour. It was observed diverse physicochemical and rheological behaviour among the studied dry-set mortars. The rheological behaviour diversity of dry-set mortars were due to the synergy among some composition parameters, specially the granular distribution. The Squeeze Flow was considered a suitable tool for the characterization of dry-set mortars and contributed to develop hypotetical behaviour models that allowed to explain the slip as stated by brazilian standards.

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