The chevron skink (Oligosoma homalonotum) is one of the largest, yet least observed skink species in New Zealand. The species was thought to have once been widespread in Northern New Zealand, however currently it is only found on Great Barrier and Little Barrier Islands. Great Barrier Island is the apparent stronghold for the species although it appears to be in decline there, despite a net increase in habitat. Recent studies have increased the understanding of the general ecology of the species, however little is known about the threats to the survival of this species. This study had two main objectives; the first was to establish if rats are a threat to chevron skinks, and the second was to increase current knowledge of the species ecology. The research was undertaken in an area of extensive rodent control (Glenfern Sanctuary) and an adjacent unmanaged reserve in Port Fitzroy, on Great Barrier Island in 2008. The first objective of this study involved confirming that rat densities in the treatment (Glenfern Sanctuary) were sufficiently different to allow meaningful comparisons of chevron skink population characteristics between sites. This was achieved by determining absolute rat densities using Zippin’s removal method at four sites, and correlating these with a relative abundance measure (tracking rates) to give confidence in the observed trends. Rat densities were high (1.94 - 3.00 rats ha-1) in the control, and low (0.00 and 0.06 rats ha-1) in the treatment sites, and these correlated well with tracking rates. In light of these clear differences between the treatment and control, the population structure and condition of chevron skinks were compared between sites. The population structure showed erosion of juvenile and sub-adult size categories, which indicated differences in vulnerabilities between size categories. Physical evidence of failed rat predation was also observed in adult skinks in the unmanaged control, which confirmed that rats were interacting with chevron skinks. Although the adults survived the attacks they suffered injuries including eye damage, punctures, cuts and tail loss. Smaller skinks would be unlikely to survive such attacks due to the severity and scale of the injuries, supporting the assertions of the population structure that smaller skinks may be more vulnerable than adults. The extent of tail loss was converted to a condition index to determine if failed rat predation was more widespread in the population, than was observed by conspicuous injuries. This condition index (body-tail condition index) was stable through all size categories in the treatment, but significantly reduced in adults in the unmanaged sites. That there was no reduction in the condition of smaller skinks in the unmanaged control sites despite high rat densities suggests that interactions between rats and smaller skinks are fatal, and thus not represented in the data. Nine chevron skinks were radio-tracked to determine habitat use, home range and ranging behaviour. Habitat use of chevron skinks was similar to a previous study and demonstrated that trees, crevices and logs were important refuge sites. Chevron skinks were more likely to be found at sites with trees, crevices and debris dams. Chevron skink home ranges indicated that adults moved further away from streams than previously anticipated at this time of year, and skinks demonstrated site fidelity. There was also overlap in home ranges between individuals, and skinks with overlapping home ranges shared common refuges. During flooding events, chevron skinks exhibited an arboreal response that appears to be a behaviour specific to stream associated animals, which allows them to avoid being taken by floodwaters.

The chevron skink (Oligosoma homalonotum) is one of the largest, yet least observed skink species in New Zealand. The species was thought to have once been widespread in Northern New Zealand, however currently it is only found on Great Barrier and Little Barrier Islands. Great Barrier Island is the apparent stronghold for the species although it appears to be in decline there, despite a net increase in habitat. Recent studies have increased the understanding of the general ecology of the species, however little is known about the threats to the survival of this species. This study had two main objectives; the first was to establish if rats are a threat to chevron skinks, and the second was to increase current knowledge of the species ecology. The research was undertaken in an area of extensive rodent control (Glenfern Sanctuary) and an adjacent unmanaged reserve in Port Fitzroy, on Great Barrier Island in 2008. The first objective of this study involved confirming that rat densities in the treatment (Glenfern Sanctuary) were sufficiently different to allow meaningful comparisons of chevron skink population characteristics between sites. This was achieved by determining absolute rat densities using Zippin’s removal method at four sites, and correlating these with a relative abundance measure (tracking rates) to give confidence in the observed trends. Rat densities were high (1.94 - 3.00 rats ha-1) in the control, and low (0.00 and 0.06 rats ha-1) in the treatment sites, and these correlated well with tracking rates. In light of these clear differences between the treatment and control, the population structure and condition of chevron skinks were compared between sites. The population structure showed erosion of juvenile and sub-adult size categories, which indicated differences in vulnerabilities between size categories. Physical evidence of failed rat predation was also observed in adult skinks in the unmanaged control, which confirmed that rats were interacting with chevron skinks. Although the adults survived the attacks they suffered injuries including eye damage, punctures, cuts and tail loss. Smaller skinks would be unlikely to survive such attacks due to the severity and scale of the injuries, supporting the assertions of the population structure that smaller skinks may be more vulnerable than adults. The extent of tail loss was converted to a condition index to determine if failed rat predation was more widespread in the population, than was observed by conspicuous injuries. This condition index (body-tail condition index) was stable through all size categories in the treatment, but significantly reduced in adults in the unmanaged sites. That there was no reduction in the condition of smaller skinks in the unmanaged control sites despite high rat densities suggests that interactions between rats and smaller skinks are fatal, and thus not represented in the data. Nine chevron skinks were radio-tracked to determine habitat use, home range and ranging behaviour. Habitat use of chevron skinks was similar to a previous study and demonstrated that trees, crevices and logs were important refuge sites. Chevron skinks were more likely to be found at sites with trees, crevices and debris dams. Chevron skink home ranges indicated that adults moved further away from streams than previously anticipated at this time of year, and skinks demonstrated site fidelity. There was also overlap in home ranges between individuals, and skinks with overlapping home ranges shared common refuges. During flooding events, chevron skinks exhibited an arboreal response that appears to be a behaviour specific to stream associated animals, which allows them to avoid being taken by floodwaters.

La investigación realizada se enfoca en la evaluación del pabellón B del Hospital Luis Negreiros Vega con planos modificados aplicando disipadores de fluido viscoso en la disposición chevron diagonal y horizontal. En el modelo numérico se aplicaron disipadores lineales y no lineales de acuerdo con las expresiones del FEMA, 356, con el fin de realizar una comparación de la disposición y valor de exponente de velocidad óptimo para una deriva objetivo y amortiguamiento efectivo planteado para cada dirección. Los resultados con los cuales se evaluó esta efectividad, son mejores reducciones de distorsiones, menores fuerzas de disipación, y reducción de la irregularidad torsional que presentaba la estructura inicialmente en la dirección Y. Finalmente, entre los resultados que presenta esta investigación, son que los disipadores chevron horizontales no lineales son los más recomendables, debido a que requieren menores valores de coeficiente de amortiguamiento, reducen distorsiones en mayor medida que los otros modelos, presentan menores valores de fuerzas de disipación y reducen la irregularidad torsional en los pisos inferiores. / The research carried out focuses on the evaluation of pavilion B of the Luis Negreiros Vega Hospital with modified planes applying viscous fluid dissipators in the diagonal and horizontal chevron arrangement. In the numerical model, linear and non-linear dissipators were applied according to the FEMA expressions, 356, in order to make a comparison of the arrangement and value of the optimum speed exponent for a target drift and effective damping proposed for each direction. The results with which this effectiveness was evaluated are better reductions of distortions, lower dissipation forces, and reduction of torsional irregularity that the structure initially presented in the Y direction. Finally, among the results presented by this research, are that the Non-linear horizontal chevron heatsinks are the most recommended, because they require lower values of damping coefficient, reduce distortions to a greater extent than other models, present lower values of dissipation forces and reduce torsional irregularity in the lower floors. / Trabajo de investigación

No description available.

Résumé : Ce projet de maîtrise s’intéresse au comportement ultime d’une structure en acier, contrôlée sismiquement par des amortisseurs élastomères et des contreventements en chevron. Les séismes peuvent causer des dommages considérables quand les infrastructures et les bâtiments ne sont pas construits selon les normes et les techniques appropriées. Par conséquent, réduire l’impact des séismes revient particulièrement à construire des ouvrages sécuritaires en tenant compte bien entendu du paramètre économique. Ainsi Gauron, Girard, Paultre et Proulx ont étudié en 2009, un système de reprise de forces latérales, constitué uniquement de treventements en chevron montés en série avec des amortisseurs en caoutchouc naturel fibré ayant de nombreux avantages. Premièrement, le système reste élastique sous le séisme de design en réduisant les efforts sismiques linéaires par un facteur supérieur à R[indice inférieur d] = 3 par rapport à un cadre conventionnel. Deuxièmement, il est capable de contrôler les déplacements sous la limite du CNBC 2010 (Code National du Bâtiment du Canada 2010), et même de réduire ces derniers dans certains cas. Par conséquent, il permet de réduire les sections des poutres et des poteaux des cadres par rapport à une structure conventionnelle ainsi que les coûts de réparation après un séisme. Toutefois, le comportement à l’état limite ultime d’un tel système, ses limites et ses réserves de sécurité restaient à déterminer. Ainsi, l’objectif global de ce projet de recherche est de déterminer les différents mécanismes de ruine possibles de ce système, d’établir des limites et réserves de sécurité, et de préciser, après avoir formulé certaines recommandations, à quelles conditions il peut être utilisé dans le dimensionnement de nouvelles structures. Pour atteindre les objectifs fixés, deux essais quasi statiques ont été réalisés sur deux cadres en acier dimensionnés avec le système. Des essais dynamiques ont aussi été réalisés afin d’avoir les propriétés viscoélastiques des amortisseurs. Le premier essai a mis en évidence un mécanisme de ruine inattendu et prématuré qui a souligné un défaut majeur dans les connexions des diagonales avec l’amortisseur. Le second essai a révélé un des mécanismes de ruine envisagés initialement où le caoutchouc se déchire après l’initiation du flambement dans la diagonale comprimée. Les résultats expérimentaux ont montré que l’amortisseur constitue le maillon faible du système, et que des efforts parasites peuvent réduire significativement la capacité portante des structures dimensionnées avec un tel système. Dans les deux cas, les résultats ont montré que la méthode de dimensionnement du système tel qu’elle est définie actuellement mérite d’être améliorée. En ce sens, des recommandations relatives au dimensionnement des différents éléments des structures dimensionnées avec le système ont été élaborées, particulièrement en ce qui concerne le caoutchouc et les connexions. // Abstract : This thesis focuses on the ultimate behavior of steel structures, controlled seismically by elastomeric dampers and chevron bracings. Earthquakes can cause considerable damages when infrastructures and buildings are not built considering appropriate standards and technics. Therefore, mitigating the impact of earthquakes means essentially building safe structures by taking account of economic parameters too. Thus Gauron, Girard, Paultre and Proulx studied in 2009 a seismic force resisting system consisting only of chevron braces connected in series with fiber-reinforced natural rubber dampers that offers many benefits. First, the system remains elastic under the design earthquake by reducing linear seismic efforts by a factor of R[subscript d] = 3 compared to a conventional frame. Secondly, it allows to control the displacements under the limits of NBCC 2010 (National Building Code of Canada 2010), and even to reduce them in some cases. Therefore, it allows a reduction of sections of beams and columns of conventional frames and it prevents repairing costs of the structure after an earthquake. However, the ultimate limit state behavior of this system, its limitations and safety reserves have not been determined yet. Thus, the overall objective of this project is to determine the different possible failure mechanisms of the system, to set its limits and safety reserves, and to state after some recommendations, how it can be used in the design of new structures. To achieve these objectives, two quasi static tests were performed on two steel frames designed with the new system. Dynamic tests were also conducted to get the viscoelastic properties of the damping material. The first quasi static test revealed an unexpected and premature failure mechanism that pointed out a major flaw in the connections of the braces with the damper. The second test revealed one of the failure mechanisms originally expected where the rubber tears after buckling of the compression brace. The experimental results have shown that the damper is the weak element in the system, and that additional forces can significantly reduce the structural capacity of structures designed with the system. In both cases, the results have shown that the actual design method of the system should be improved. Thus, recommendations for the design of elements of structures designed with this system have been developed, particularly with regard to the rubber and brace connections.

Since the discovery of oil in Nigeria, way back in 1950s, the country has invariably suffered some negative environmental consequences such as oil pollution resulting from gas flaring and oil extraction, loss of mangrove trees, which before now was a source of livelihood for the indigenous people and habitat for the area’s biodiversity. Oil production activities have caused contamination of marine life, and habitat, which in turn have had negative consequences on the health of humans, who consume the sea food. Inadequate attention had been paid by the successive Governments of Nigeria and the oil companies to these environmental problems over the years. In this study, an assessment of the effects of oil and gas exploration and exploitation on the nearby communities in some of Chevron’s operational areas was carried out using the Ugborodo community as a case study. Furthermore, investigations were carried out on the toxicity effects of the Escravos crude oil on aquatic organisms like Tilapia and a terrestrial organism such as the Earthworms (Lumbricus terrestris,). The study established the effect and the impact of crude oil when exposed to such organisms mentioned above. The rate of death of barbus fingerlings of Tilapia and the Earthworm (Lumbricus Terrestris) at different concentrations of crude oil was determined and reported. The community survey undertaken by polling data shows the dwindling of the natural resources of the area due to oil exploration and the survey indicate the impacts on natural resources from pollution by crude oil and the consequences on the affected communities using the Ugborodo community in the Chevron’s Nigeria Limited Operational base as a case study. / Environmental Sciences / M.Sc. (Environmental Management)

<p>Bonding techniques intended for assembling space microsystems are studied in this work. One of the largest problems in bonding pre-processed semiconductor wafers are the severe process restrictions imposed by material compatibility issues. Plasma processes have shown to be good for sensitive materials integration why the influence of different plasma parameters on the bondability of wafers is particularly studied. Conventional wet chemical and field-assisted methods are also examined. The resulting bond quality is assessed in terms of mechanical strength, homogeneity, and yield.</p><p>The effect of spaceflight environment on the reliability of wafer bonds is also investigated. Both high and low temperature annealed bonds are found to be very robust. Effects observed are that low temperature bonds are reinforced by thermal cycling in vacuum and that high temperature bonds degrade slightly by low dose γ irradiation.</p><p>Adhesion quantification is important for all bonding. Development of accurate quantification methods is considered necessary since most methods at hand are limited. This work includes the development of the blister test method. Former test structures are improved to be more practical to work with and to yield low experimental scatter. A physical stress model for the improved structure is suggested with which successful predictions of fracture for different test specimen configurations are made. The blister test method is used throughout this work to assess the strength of wafer bonds. The physics background and modelling of other common test methods are also thoroughly analysed. The methods’ practical capabilities and limitations are commented; origin and mitigation of measurement errors are discussed. It is shown that all methods can be significantly improved by small means.</p><p>Weibull statistics is introduced as a tool to characterise wafer bonds. This method is suitable to use in brittle materials design as the inherent variability in strength can be properly accounted for.</p>

Bonding techniques intended for assembling space microsystems are studied in this work. One of the largest problems in bonding pre-processed semiconductor wafers are the severe process restrictions imposed by material compatibility issues. Plasma processes have shown to be good for sensitive materials integration why the influence of different plasma parameters on the bondability of wafers is particularly studied. Conventional wet chemical and field-assisted methods are also examined. The resulting bond quality is assessed in terms of mechanical strength, homogeneity, and yield. The effect of spaceflight environment on the reliability of wafer bonds is also investigated. Both high and low temperature annealed bonds are found to be very robust. Effects observed are that low temperature bonds are reinforced by thermal cycling in vacuum and that high temperature bonds degrade slightly by low dose γ irradiation. Adhesion quantification is important for all bonding. Development of accurate quantification methods is considered necessary since most methods at hand are limited. This work includes the development of the blister test method. Former test structures are improved to be more practical to work with and to yield low experimental scatter. A physical stress model for the improved structure is suggested with which successful predictions of fracture for different test specimen configurations are made. The blister test method is used throughout this work to assess the strength of wafer bonds. The physics background and modelling of other common test methods are also thoroughly analysed. The methods’ practical capabilities and limitations are commented; origin and mitigation of measurement errors are discussed. It is shown that all methods can be significantly improved by small means. Weibull statistics is introduced as a tool to characterise wafer bonds. This method is suitable to use in brittle materials design as the inherent variability in strength can be properly accounted for.

La démarche de Pierre Bergounioux, écrivain français contemporain (1949-), témoigne d'une obsession: dire d'où vient ce « je » qui parle, sent et voit; retrouver d'où lui vient cette manière de dire, de sentir, de voir; comme s'il s'agissait chaque fois d'inventer la mémoire du commencement. Cette écriture parait se structurer à partir de failles qui correspondent manifestement à l'origine, zones d'« ombre », angles morts, points aveugles où un réel échappe, demeure en reste de la symbolisation, du langage. Ces rouages de l'écriture construiraient et constitueraient le sujet de l'énonciation tout en témoignant de son surgissement. Afin de porter au jour ce sujet, ce mémoire s'intéresse aux dispositifs de la représentation: Il s'agit de se mettre à l'écoute non pas de ce que les textes disent, mais de ce qu'ils font. Dans la première partie intitulée Mémoire de l'origine, les phénomènes particuliers, les figures ainsi que les motifs récurrents ont été repérés en suivant l'ordre de leur surgissement dans chacun des trois textes à l'étude: La Bête faramineuse (1986), Le Chevron (1996) et Le Premier mot (2001). L'analyse des modes d'articulation des deux deuils présentés dans La Bête... -deuils d'un aïeul et de l'innocence -, a contribué à la mise en évidence du travail de l'imaginaire. Par la suite, la structure particulière du Chevron a permis de voir que l'écriture de Bergounioux est aux prises avec un désir de dire l'origine dont la satisfaction est à la fois nécessaire et impossible, créant une dynamique inépuisable à l'image de celle relative au paysage décrit dans le récit. Enfin, dans Le Premier mot, nous nous sommes intéressés aux effets suscités par la volonté de s'arracher aux déterminismes inhérents à la condition du sujet d'emblée soumis à l'image et au désir d'un autre qui le précède. Les trois ouvrages mettent donc de l'avant un sujet principalement travaillé, voire déterminé par l'imaginaire (La Bête... ), l'espace géographique (Le Chevron) et les ancêtres, les parents (Le Premier mot). L'analyse de ce sujet toujours déjà étranger à lui-même, subordonné aux lois d'un curieux désir qui l'inscrit dans une lignée et l'arrime à l'espèce a permis de dégager des similitudes avec certains phénomènes observés par Freud puis Lacan et qui régissent la vie psychique de l'être parlant. Ces caractéristiques témoignent dirait-on d'un corps particulier qui se trouve construit par et dans l'écriture. Dans la deuxième partie intitulée La trace, ce mémoire cherche à révéler les rouages de ce corps d'écriture, corps invisible, étranger et soumis aux lois du langage, du désir et du temps. Chacun des ouvrages étudiés présente une énonciation qui joue à sa façon de l'inscription temporelle du sujet. Puisqu'il se trouve stratifié, le temps qui s'inscrit dans la conscience donne lieu à des effets particuliers. Par exemple, le travail de mémoire de cette écriture s'accompagne de motifs récurrents, ainsi que de métaphores redondantes qui créent une espèce d'orbite autour de ce qui cherche à se dire. Il nous a semblé que cette dynamique de répétition s'inscrit à la place d'une trace suscitée par l'absence radicale correspondant à l'origine qui, à la fois irréductible et immémoriale, instaure une béance au coeur du sujet. ______________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : Pierre Bergounioux, Mémoire, Origine, Langage, Désir, Psychanalyse, Énonciation, Temps, Trace mnésique.

Since the discovery of oil in Nigeria, way back in 1950s, the country has invariably suffered some negative environmental consequences such as oil pollution resulting from gas flaring and oil extraction, loss of mangrove trees, which before now was a source of livelihood for the indigenous people and habitat for the area’s biodiversity. Oil production activities have caused contamination of marine life, and habitat, which in turn have had negative consequences on the health of humans, who consume the sea food. Inadequate attention had been paid by the successive Governments of Nigeria and the oil companies to these environmental problems over the years. In this study, an assessment of the effects of oil and gas exploration and exploitation on the nearby communities in some of Chevron’s operational areas was carried out using the Ugborodo community as a case study. Furthermore, investigations were carried out on the toxicity effects of the Escravos crude oil on aquatic organisms like Tilapia and a terrestrial organism such as the Earthworms (Lumbricus terrestris,). The study established the effect and the impact of crude oil when exposed to such organisms mentioned above. The rate of death of barbus fingerlings of Tilapia and the Earthworm (Lumbricus Terrestris) at different concentrations of crude oil was determined and reported. The community survey undertaken by polling data shows the dwindling of the natural resources of the area due to oil exploration and the survey indicate the impacts on natural resources from pollution by crude oil and the consequences on the affected communities using the Ugborodo community in the Chevron’s Nigeria Limited Operational base as a case study. / Environmental Sciences / M.Sc. (Environmental Management)