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Investigating the Influence of Mechanical anisotropy on the Fracturing Behaviour of Brittle Clay Shales with Application to Deep Geological RepositoriesLisjak Bradley, Andrea 10 January 2014 (has links)
Clay shales are currently being assessed as possible host rock formations for the deep geological disposal of radioactive waste. However, one main concern is that the favourable long-term isolation properties of the intact rock mass could be negatively affected by the formation of an excavation damaged zone (EDZ) around the underground openings. This thesis investigated the deformation and failure process of a clay shale, namely Opalinus Clay, with particular focus on the influence of anisotropy on the
short-term response of circular tunnels. To achieve this goal, a hybrid continuum-discontinuum numerical approach was used in combination with new field measurements from the Mont Terri underground research laboratory. The response of Opalinus Clay during the excavation of a full-scale emplacement (FE) test tunnel was characterized by geodetic monitoring of wall displacements, radial extensometers
and longitudinal inclinometers. The deformation measurements indicated strong directionality induced by the combined effect of in situ stress field and presence of bedding planes striking parallel to the
tunnel axis, with the most severe deformation occurring in the direction approximately perpendicular to the material layering. Computer simulations were conducted using a newly-extended combined
finite-discrete element method (FEM/DEM), a numerical technique which allows the explicit simulation of brittle fracturing and associated seismicity. The numerical experimentation firstly focused on the
laboratory-scale analysis of failure processes (e.g., acoustic activity) in brittle rocks, and on the role of
strength and modulus anisotropy in the failure behaviour of Opalinus Clay in tension and compression.
The fracturing behaviour of unsupported circular excavations in laminated rock masses was then analyzed under different in situ stress conditions. Lastly, the modelling methodology was applied to the
aforementioned FE tunnel to obtain original insights into the possible EDZ formation process around emplacement tunnels for nuclear waste. The calibrated numerical model suggested delamination along bedding planes and subsequent extensional fracturing as key mechanisms of the damage process potentially leading to buckling and spalling phenomena. Overall, the research findings may have a potential impact on the constructability and support design of an underground repository as well as implications for its long-term safety assessment procedure.
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Investigating the Influence of Mechanical anisotropy on the Fracturing Behaviour of Brittle Clay Shales with Application to Deep Geological RepositoriesLisjak Bradley, Andrea 10 January 2014 (has links)
Clay shales are currently being assessed as possible host rock formations for the deep geological disposal of radioactive waste. However, one main concern is that the favourable long-term isolation properties of the intact rock mass could be negatively affected by the formation of an excavation damaged zone (EDZ) around the underground openings. This thesis investigated the deformation and failure process of a clay shale, namely Opalinus Clay, with particular focus on the influence of anisotropy on the
short-term response of circular tunnels. To achieve this goal, a hybrid continuum-discontinuum numerical approach was used in combination with new field measurements from the Mont Terri underground research laboratory. The response of Opalinus Clay during the excavation of a full-scale emplacement (FE) test tunnel was characterized by geodetic monitoring of wall displacements, radial extensometers
and longitudinal inclinometers. The deformation measurements indicated strong directionality induced by the combined effect of in situ stress field and presence of bedding planes striking parallel to the
tunnel axis, with the most severe deformation occurring in the direction approximately perpendicular to the material layering. Computer simulations were conducted using a newly-extended combined
finite-discrete element method (FEM/DEM), a numerical technique which allows the explicit simulation of brittle fracturing and associated seismicity. The numerical experimentation firstly focused on the
laboratory-scale analysis of failure processes (e.g., acoustic activity) in brittle rocks, and on the role of
strength and modulus anisotropy in the failure behaviour of Opalinus Clay in tension and compression.
The fracturing behaviour of unsupported circular excavations in laminated rock masses was then analyzed under different in situ stress conditions. Lastly, the modelling methodology was applied to the
aforementioned FE tunnel to obtain original insights into the possible EDZ formation process around emplacement tunnels for nuclear waste. The calibrated numerical model suggested delamination along bedding planes and subsequent extensional fracturing as key mechanisms of the damage process potentially leading to buckling and spalling phenomena. Overall, the research findings may have a potential impact on the constructability and support design of an underground repository as well as implications for its long-term safety assessment procedure.
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Dietary choline and vitamin/mineral supplement for recovery from early cortical injuryHalliwell, Celeste, University of Lethbridge. Faculty of Arts and Science January 2003 (has links)
Early cortical injury has been attributed to the consequential effects of various factors, such as alcohol, drug addiction, smoking, and inadequate nutrient intakes during periods of pregnancy and lactation, or delivery of infants by forceps, and premature deliveries. These are only a few examples of circumstances, or "injury", that may result in disorders ranging from mild learning difficulties to aggressive behaviour. Injury to the cortex during the early years of development has been know to result in poor behavioural outcome into adulthood. Presently, the most common form of treatment includes a pharmacological agent, which may be accompanied with behavioral modification therapies supported by families. As an alternative form of therapy towards the treatment of early cortical injury, choline and a vitamin and mineral supplement (EM Power+) were used to determine the possibilities of nutrition intervention in an animal model. The injuries were incurred by aspiration lesion at days three, (Exp.1) and four, (Exp.2) and lesions were localized to the midline medial frontal cortex in some rats, while a different group of rats received lesions in the posterior parietal cortex. The pre-and postnatal choline treated animals showed favorable results for the medial frontal lesions, and the postnatal vitamin supplement treated animals showed favorable results for treatment in both medial frontal and posterior parietal lesions. All animals were tested in adulthood indicating that nutrition intervention is very beneficial for alleviating some of the functional deficits commonly seen from early cortical injury. / xiv, 191 leaves : ill. ; 28 cm.
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Identification of civil engineering structuresGarcés, Francisco 22 February 2008 (has links) (PDF)
This thesis presents three methods to estimate and locate damage in framed buildings, simply-supported beams and cantilever structures, based on experimental measurements of their fundamental vibration modes. Numerical simulations and experimental essays were performed to study the effectiveness of each method. A numerical simulation of a multi-storey framed building, a real bridge and a real chimney were carried out to study the effectiveness of the methodologies in identifying damage. The influence of measurement errors and noise in the modal data was studied in all cases. To validate the experimental effectiveness of the damage estimation methods, static and dynamics tests were performed on a framed model, a simply supported beam, and a cantilever beam in order to determine the linear behavior changes due to the increase of the level of damage. The structural identification algorithms during this thesis were based on the knowledge type of the stiffness matrix or flexibility matrix to reduce the number of modal shapes and required coordinates for the structural assessment. The methods are intended to develop tools to produce a fast response and support for future decision procedures regarding to structures widely used, by excluding experimental information, thereby allowing a cost reduction of extensive and specific testing
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Prolongation de la durée de vie des ouvrages en béton armé / Extending the service life of reinforced concrete structuresKreit, Amjad 25 September 2012 (has links)
L'efficacité de la technique NSM dans la réparation et renforcement des structures est fortement dépendante de la performance d’adhérence entre les joncs de carbone et le béton. De nombreuses études récentes ont été réalisées pour quantifier d’adhérence sur des éprouvettes saines en raison de la complexité de ce problème. Par contre, le comportement des éléments réparés peut être affecté, d’une part, selon les conditions de pré-chargement, et d’autre part, selon l’endommagement spécifique, qui pourraient être rencontrés dans les structures existantes. En effet, un endommagement dans le béton ou dans les armatures peut modifier le comportement global des éléments réparés en réduisant la capacité portante.Tout d’abord, des essais à grande échelle en flexion ont été réalisés pour étudier le comportement des poutres en béton armé. D’une part, différents types d’endommagements ont été considérés tels que la corrosion des aciers et les charges excessives. D’autre part, différentes conditions de pré-chargement incluant les maintiens du chargement à l’heure de la mise en oeuvre de la réparation ont été étudiées. Le comportement de la poutre témoin renforcée se distingue par son côté fragile qui s’accompagne d’une ruine soudaine par pull-out du jonc de carbone de la résine suivie d’éclatement de morceaux de béton dans la zone de béton d’enrobage et d’un écrasement du béton comprimé. Par contre, la ruine de la poutre corrodée et réparée intervient par séparation (délamination) du béton d’enrobage dans la zone tendue au niveau à l’insertion du jonc de carbone, qui a commencé entre deux fissures de flexion dans la zone centrale et s’est propagé vers l’appui. Ensuite, afin de comprendre l’origine du mode de ruine de la poutre corrodée et réparée, et d'étudier le comportement global, la rigidité, la ductilité, le mode de ruine, et la capacité portante, des essais expérimentaux ont été réalisés en faisant varier les paramètres relatifs aux conséquences de la corrosion (perte généralisée de la section d’acier tendu, éclatement du béton d’enrobage, détérioration de l’adhérence acier-béton). Cependant, la ruine par la séparation du béton d’enrobage entre deux fissures adjacentes observé sur la poutre corrodée et réparée n’a jamais été obtenue. Pour nos simulations : La ruine a eu lieu par Pull-out du jonc de carbone. Dans tous les cas, la capacité portante mesurée des poutres endommagées puis réparées était supérieure à celle de la poutre témoin (non-renforcée)Finalement, puisque les structures nécessitant de la réparation par application de matériaux composites ne sont pas de récentes, et par conséquent, qui ont déjà subi un certain nombre d’endommagements dus aux contraintes mécaniques (surcharge maintenue à long-terme, charge accidentelle à court-terme), une partie expérimentale s’est intéressée à l'utilisation des joncs de carbone pour la réparation des éléments endommagés par une charge excessive, puis réparés sous ou sans charge maintenue. Un endommagement est capable de réduire légèrement la capacité portante des poutres réparées (moins de 8% par rapport à la poutre témoin renforcée). La réparation des poutres sous charge maintenue a une influence non-significative en diminuant la capacité portante entre 5% et 6% par rapport aux poutres endommagées réparées sans charge maintenue. La ruine des poutres pré-chargées puis réparées a été par l’arrachement du jonc de carbone de la résine « Pull-out » à cause des fissures longitudinales développées dans la résine qui conduit à la perte d'adhérence entre le jonc de carbone et le matériau de scellement en réduisant légèrement leur capacité portante. Par contre, les poutres endommagées par chargement excessif puis réparées ont montré un mode de ruine différent (par écrasement du béton comprimé) mais avec une réduction significative leur capacité portante / The effectiveness of the NSM technique for repairing or strengthening the RC structures is highly dependent on the bond strength behavior between CFRP rods and concrete. Many recent studies have been conducted to evaluate bond strength on undamaged concrete specimens because of the complexity of this problem. On the contrary, the behavior of repaired specimens may be affected, first, by pre-loading conditions, and the other, depending on specific damage that could be encountered in the existing structures. Indeed, damage in concrete or in reinforcement can change the global behavior of repaired elements by reducing the bearing capacity.First, large-scale bending tests were carried out to study the behavior of reinforced concrete beams. On the one hand, various types of damage were considered such as the steel corrosion and excessive loads. On the one hand, different pre-loading conditions including sustaining loads at the time of implementation repair were studied. The behavior of the beam strengthened control is distinguished by its fragile side which is accompanied by sudden failure due to pull-out of the CFRP NSM rod, followed by splitting of concrete pieces in the concrete cover and a crushing of concrete in compressive zone. On the other hand, the failure mode of corroded repaired beam occurred by concrete cover delamination in the tension zone at the level of insertion of CFRP NSM rod that started between two bending cracks in the central area and has spread to the support. Then, in order to understand the origin of the failure mode, global behavior, stiffness, ductility, and bearing capacity of repaired corroded beam, an experimental tests were performed by varying the parameters relating to the consequences of corrosion (such as generalized loss of bottom steel section, concrete cover delamination failure and bond strength failure between concrete and reinforcing steel). However, the failure occurred by the concrete cover delamination between two adjacent bending cracks was never obtained on the repaired corroded beam. For our simulations: The failure was due to pull-out of CFRP rod. In all cases, the bearing capacity measured for repaired damaged beams was greater than that of control beam (non-repaired).Finally, since the structures requiring repair by applying composite materials are not recent, and consequently, number of damages occurred due to mechanical stress (long-term sustained overloading, short term accidental load), an experimental part was interested in the use of CFRP NSM rods to repair of beams damaged by excessive load, and then repaired under or without sustained load. A damage can slightly reduce the bearing capacity of the repaired beams (less than 8% compared to the strengthened control beam). The repair of beams under sustained load has a non-significant effect by reducing the bearing capacity between 5% and 6% compared to the damaged beams repaired without sustained load. The damages of the pre-loaded RC beams repaired with NSM failed by the tearing of the carbon rod "pull-out" due to the longitudinal cracks developed in the epoxy resin volume, which leads to loss of adhesion between the CFRP rod and the sealing material by slightly reducing their bearing capacity. While, the RC beams damaged by overloading which were repaired showed a different mode of failure (crushing of concrete in compression) with also a significant reduction in their ultimate bearing capacity values
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Uso do SIG como ferramenta de auxílio na recuperação de áreas degradadas / Use of GIS as management tool on restoration of damaged areasRoberto Simão Júnior 19 June 2001 (has links)
Pesquisou-se o uso do Sistema de Informação Geográfica (SIG) como ferramenta de auxílio na Recuperação de Áreas Degradadas (RAD), dentro de uma proposta de um paradigma mais adequado ao tema. Como estudo de caso, utilizou-se o SIG no desenvolvimento de elementos para o planejamento da drenagem superficial de áreas mineradas pela empresa Samarco Mineração SA, Ouro Preto/MG, através da identificação de micro-bacias vulneráveis à drenagem. A falta da abordagem holística e a excessiva fragmentação do saber, tem feito os profissionais confundirem os efeitos como causas, obtendo-se pseudo-soluções, aparentemente eficientes no curto prazo, mas falhas no médio e longo prazo, como demonstrado por alguns projetores de RAD no passado, a exemplo do paradigma do \"Tapete Verde\" nas décadas de 70 e 80. Segurou-se um novo paradigma para a RAD visando-se propiciar nichos distribuídos em pontos diversos dentro das grandes áreas degradadas. Propõe-se, para tal, a divisão das águas de drenagem com vistas ao desencadeamento da sucessão ecológica, promovendo a retenção da umidade, matéria orgânica, nutrientes e propágulos. Espera-se que os conceitos aqui aventados permitam uma recuperação de áreas degradadas mais eficaz do que se tem obtido e melhor sincronizado com as exigências do controle ambiental. / This study presents an investigation of Restoration of Damaged Areas (RDA) using a Geographical Information System (GIS), within the context of an adequate paradigm for this purpose. As a case study, a GIS was employed to develop information for planning of surface drainage in areas mined by Samarco Mineração SA, Ouro Preto-MG, Brazil, identifying micro- basins vulnerable to deleterious effects of excessive drainage. A review of literature on RDA shows that there is a lack of treatments based on holistic principles emphasizing only compartmentalized knowledge. This promotes confusion as regards the causes and the effects leading to pseudo-solutions, although apparently efficient in the short run, are prejudicial in the long run, as demonstrated by some of the past RDA projects. One can mention the paradigm of \"Green Carpet\" used in 70\'s and 80\'s which limited itself to covering the damaged areas with some kind of vegetation to improve the visual aspect of such areas. A new paradigm is proposed for RDA that requires a division of the drainage flow in order to initiate ecological succession promoting retention of moisture, organic matter, nutrients and propagules. It is hoped that the concepts alluded to in this study help to obtain more efficient RDAs than those attained in the past and better attuned to the demands of modern environmental control.
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\"Assalto contra o limite\": forma danificada e história em Franz Kafka / \"Ansturm gegen die Grenze\": damaged form and history in Franz KafkaRenato Oliveira de Faria 16 August 2011 (has links)
Esta tese busca refletir sobre a configuração fragmentária da produção do escritor Franz Kafka (1883-1924). Procura-se mostrar como a partir do final de 1916 ocorre na produção kafkiana uma inflexão formal decorrente de uma mudança no modo do escritor conceber o caráter danificado de sua escrita. / This thesis reflects upon the fragmentary configuration of Franz Kafka´s production. It aims to show how, from the end of 1916, occurs an formal inflection in the Kafkaesque production due to a change in the way the writer conceives the \"damaged\" character of his writing.
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Effects of Fluency and Accuracy-Only Training on Acquisition and Retention of Letter Naming by Individuals with Traumatic Brain InjuryEwing, Christopher Boyd 08 1900 (has links)
This study examines the effects of accuracy-only training and fluency training on retention of material learned. Two adolescent participants with traumatic brain injuries were taught to name 2 sets of lowercase Greek letters. Each of the 2 sets consisted of 7 letters. Practice and rate of reinforcement were controlled for in this study. Fluency trained letters showed higher retention (percent correct during retention checks) than the accuracy-only trained letters.
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Traumatic Brain Injury in Children and Adolescents: An Evaluation of the WISC-III Four Factor Model and Individual Cluster ProfilesShafer, Micheal E. 08 1900 (has links)
Traumatic brain injury (TBI) is the leading cause of death and disability among children and adolescents in the US. Children and adolescents who sustain moderate and severe head injuries are much more likely to evidence significant deficits in neuropsychological functioning when compared with children with mild head injuries. Information about the recovery process and functional sequelae associated with moderate and severe head injuries remains limited, despite clear indications that children who experience such injuries typically exhibit notable deficits in intellectual functioning, particularly during the acute phase of recovery. Thus, the present study was conducted to augment research on intellectual functioning in children with moderate or severe head injuries. To accomplish this, the study first examined the proposed factor model of the WISC-III in children with moderate and severe TBI. Given high prevalence rates and similar trends in cognitive impairment, particularly within the frontal lobe structures (e.g., disrupted cognitive flexibility and divided attention), the study also examined this same factor model for a group of children with attention-deficit/hyperactivity disorder (ADHD) and compared it with the model fit from the TBI group. In the second phase of the study, both the TBI and AHDH groups were evaluated to determine if distinct WISC-III index score cluster profiles could be identified. Lastly, the cluster groups for both the TBI and ADHD samples were validated using important demographic and clinical variables, as well as scores from independent neuropsychological measures of attention, executive functioning, and working memory. Parent reports of psychological and behavioral functioning were also used in an attempt to further distinguish the cluster groups. Study limitations and future research implications were also discussed.
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Deconstructing the “Low Other” in the First Wave of Sex Hygiene Films (1914-1919)Cârstian, Maria January 2019 (has links)
The present thesis investigates the commercial sex hygiene films produced between the years 1914 and 1919 in the United States, during the last years of the Progressive Era. Rejected and prohibited as soon as five years after their apparition, the sex hygiene films’ position within the industry, as well as the cinematic techniques they incorporated, will be analysed through the concept of the Low Other. The first part of the thesis aims to delineate the used concepts, as well as integrate the sex hygiene film into a wider cultural, social, and political framework. The second part explores the films’ aesthetic construction, then focuses on a textual analysis of the narrative and non-narrative methods implied by three particular sex hygiene films. Finally, the thesis concludes that the films used a series of cinematic methods to create a Low Other on-screen, yet these very methods ultimately played a part within their suppression as a Low Other body of culture.
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