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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.
81

An Urban Edge for Innovation & Reservation: create a figurative stage for students to perform their lives

Wu, Kejia 14 February 2011 (has links)
The architect, as a coordinator of complex conditions and different disciplines, has a role in the development of the master plan for the entire site, balancing technical innovation with appreciation for cultural inheritance. This thesis attempts to explore approaches to design decision making, as a response to a project's site, its history, and the larger cultural context. The above issues are investigated through the design of a multipurpose building at the east end of the Drillfield on the Virginia Tech campus in Blacksburg, Virginia. The building will form a "stage" to accommodate the daily life of the campus. In addition, the proposal was conceived to: a. emphasize both axial and radial geometric features of the site; b. redefine the edge of the oval Drillfield; c. create magnetic force between the proposed building and the existing War Memorial Chapel; d. translate the idea into tectonics. / Master of Architecture
82

Geophysical Study at Old Stone Fort State Archaeological Park, Manchester, Tennessee

Yerka, Stephen Jay 01 December 2010 (has links)
The Old Stone Fort State Archaeological Park covers over 800 acres within Manchester, Tennessee, and is owned and managed by the Tennessee Division of State Parks. The central archaeological site within the park boundary is The Old Stone Fort mounds that enclose about 50 acres on a plateau above the convergence of the Big Duck and the Little Duck Rivers. The hilltop enclosure dates to the Middle Woodland Period, and radiocarbon dates obtained at the site range from the first to the fifth century A. D. Because of its size and apparent complexity, previous investigations of the site have been quite limited in areal exposure. Many questions remain as to the overall structure of the site, including the relationship of built and natural features, the presence of any structures or other anthropogenic features, and the occurrence of presence of any domestic remains. This research project utilizes detailed digital topographic survey, geographical information system (GIS) analysis, geophysical survey, limited re-excavation of previously investigated portions of the site, and manual coring to locate and characterize archaeological deposits within the enclosure and mounds. Magnetometer, resistance, electromagnetic susceptibility, conductivity, and ground penetrating radar techniques were used during the investigations. Geophysical data, using these instruments, were collected over the same area in many cases. All together 20,000 m2 were examined during the project. Results indicate potential archaeological features and deposits within the plateau interior. Analysis suggests the presence of several geophysical anomalies potentially associated with prehistoric use of the site, especially within the Eastern Gateway complex. One such anomaly, or complex of anomalies, represents a possible structure. Historic archaeological deposits are also indicated by the geophysical data. Excavations at the site were limited to minimize impact. In a re-excavated trench, a lens of black shale within the stone mound construction may indicate a building stage not previously observed at Old Stone Fort. A second excavation confirmed a ditch feature detected in the geophysical survey. Archaeological deposits located during the survey are interpreted as evidence of sustained use of the ceremonial site during the Middle Woodland Period by local corporate groups to maintain and intensify membership for individuals who were settled in nucleated villages throughout most of the year.
83

Vapour Diffusion Control in Framed Wall Systems Insulated with Spray Polyurethane Foam

Smith, Rachel Cecilia January 2009 (has links)
The Intergovernmental Panel on Climate Change (IPCC) estimates that buildings account for 40% of the global energy use. The IPCC believes substantial improvements to building efficiency can be implemented easily by improving building enclosures through increased levels of insulation, optimizing glazing areas and minimizing infiltration of outside air.<br><br> Building enclosure design encompasses a wide range of parameters but the transport of heat, air and moisture through the enclosure is of primary importance. In predominantly cold Canadian climates, adequate thermal insulation, effective air barriers, and proper moisture control are crucial for energy savings and durability of the structure.<br><br> For decades, standard construction practice in Canada dictated a polyethylene sheet behind the interior drywall layer to serve as a vapour barrier for assemblies with traditional fibre-based cavity insulation. If the polyethylene sheet was sealed carefully enough it had the added benefit of reducing air leakage. Unfortunately, vapour barriers place the emphasis on the wrong moisture transport mechanism; air leakage can have 10 times or greater the wetting potential than vapour diffusion. Regardless, code enforcement personnel continued (and continue in some areas) to require vapour barriers in all climates, all assemblies, and all occupancies. To do so, they overrule the provision in Part 5 of The National Building Code of Canada that states vapour barriers are not required if it can be shown that the uncontrolled vapour diffusion will not affect the operation of the building and systems, or the health and safety of the occupants.<br><br> Foam plastic insulations perform better than fibre-based insulation in terms of the combined resistance to transmission of heat, air and vapour. This research investigated several types of open cell and closed cell spray polyurethane foam insulation in a variety of assembly configurations both in lab tests and hygrothermal simulations. The simulations were extrapolated to seven Canadian climate categories and three levels of interior relative humidity. The goal was to determine which spray polyurethane foam applications required the addition of a dedicated vapour barrier layer beyond what the foam itself could provide.<br><br> The moisture content of the oriented strand board sheathing layer (OSB) in the tested and modelled assemblies was used as the performance evaluation point because during wintertime vapour drives, the wood sheathing is the most likely condensing surface. Prolonged high moisture content (greater than 20%) in wood and wood products in wall assemblies leads to mould growth and decay. By this measure, if the wood sheathing moisture contents stay within the safe range (less than 19%) a vapour barrier is not necessary. The results are presented in Table 7-4.<br><br> The performance of assemblies containing closed cell spray foam was excellent for all climates and humidity levels. Their performance was equivalent to traditional wall assemblies incorporating a polyethylene sheet vapour barrier. The performance of assemblies with open cell spray foam was equivalent to traditional wall assemblies containing no vapour barrier. Open cell spray foam and fibreglass batt both require additional vapour control layers with all but the mildest Canadian climates with the lowest interior humidities. However, in those mild climates with low interior humidities, the only vapour control layer required was a medium permeance latex paint with primer.<br><br>
84

Vapour Diffusion Control in Framed Wall Systems Insulated with Spray Polyurethane Foam

Smith, Rachel Cecilia January 2009 (has links)
The Intergovernmental Panel on Climate Change (IPCC) estimates that buildings account for 40% of the global energy use. The IPCC believes substantial improvements to building efficiency can be implemented easily by improving building enclosures through increased levels of insulation, optimizing glazing areas and minimizing infiltration of outside air.<br><br> Building enclosure design encompasses a wide range of parameters but the transport of heat, air and moisture through the enclosure is of primary importance. In predominantly cold Canadian climates, adequate thermal insulation, effective air barriers, and proper moisture control are crucial for energy savings and durability of the structure.<br><br> For decades, standard construction practice in Canada dictated a polyethylene sheet behind the interior drywall layer to serve as a vapour barrier for assemblies with traditional fibre-based cavity insulation. If the polyethylene sheet was sealed carefully enough it had the added benefit of reducing air leakage. Unfortunately, vapour barriers place the emphasis on the wrong moisture transport mechanism; air leakage can have 10 times or greater the wetting potential than vapour diffusion. Regardless, code enforcement personnel continued (and continue in some areas) to require vapour barriers in all climates, all assemblies, and all occupancies. To do so, they overrule the provision in Part 5 of The National Building Code of Canada that states vapour barriers are not required if it can be shown that the uncontrolled vapour diffusion will not affect the operation of the building and systems, or the health and safety of the occupants.<br><br> Foam plastic insulations perform better than fibre-based insulation in terms of the combined resistance to transmission of heat, air and vapour. This research investigated several types of open cell and closed cell spray polyurethane foam insulation in a variety of assembly configurations both in lab tests and hygrothermal simulations. The simulations were extrapolated to seven Canadian climate categories and three levels of interior relative humidity. The goal was to determine which spray polyurethane foam applications required the addition of a dedicated vapour barrier layer beyond what the foam itself could provide.<br><br> The moisture content of the oriented strand board sheathing layer (OSB) in the tested and modelled assemblies was used as the performance evaluation point because during wintertime vapour drives, the wood sheathing is the most likely condensing surface. Prolonged high moisture content (greater than 20%) in wood and wood products in wall assemblies leads to mould growth and decay. By this measure, if the wood sheathing moisture contents stay within the safe range (less than 19%) a vapour barrier is not necessary. The results are presented in Table 7-4.<br><br> The performance of assemblies containing closed cell spray foam was excellent for all climates and humidity levels. Their performance was equivalent to traditional wall assemblies incorporating a polyethylene sheet vapour barrier. The performance of assemblies with open cell spray foam was equivalent to traditional wall assemblies containing no vapour barrier. Open cell spray foam and fibreglass batt both require additional vapour control layers with all but the mildest Canadian climates with the lowest interior humidities. However, in those mild climates with low interior humidities, the only vapour control layer required was a medium permeance latex paint with primer.<br><br>
85

Concurrent fire dynamic models and thermomechanical analysis of steel and concrete structures

Choi, Joonho 21 October 2008 (has links)
The objective of this study is to formulate a general 3D material-structural analysis framework for the thermomechanical behavior of steel-concrete structures in a fire environment. The proposed analysis framework consists of three modeling parts: fire dynamics simulation, heat transfer analysis, and a thermomechanical stress analysis of the structure. The first modeling part consists of applying the NIST (National Institute of Standards and Technology) fire dynamics simulator (FDS) where coupled Computational Fluid Dynamics (CFD) with thermodynamics are combined to model the fire progression within the steel-concrete structure. The goal is to generate the spatial-temporal (ST) solution variables (temperature, heat flux) on the surfaces of the structure. The FDS-ST solutions are generated in a discrete numerical form. Continuous FDS-ST approximations are then developed to represent the temperature or heat-flux at any given time or point within the structure. An extensive numerical study is carried out to examine the best ST approximation functions that strike a balance between accuracy and simplicity. The second modeling part consists of a finite-element (FE) transient heat analysis of the structure using the continuous FDS-ST surface variables as prescribed thermal boundary conditions. The third modeling part is a thermomechanical FE structural analysis using both nonlinear material and geometry. The temperature history from the second modeling part is used at all nodal points. The ABAQUS FE code is used with newly developed external user subroutines for the second and third simulation parts. The main objective is to describe the nonlinear temperature-dependency of the specific heat of concrete materials, especially high-strength concretes, that drastically affects their transient thermal solution. New algorithms are also developed to apply the continuous FDS-ST surface nodal boundary conditions in the transient heat FE analysis. The proposed modeling framework is applied to predict the temperature and deflection of the well-documented Cardington fire tests and to predict the time-to-collapse of the recent Oakland bridge fire caused by a fuel-truck accident.
86

Vybrané aspekty vlivu bezobratlých herbivorů na složení travinného společenstva

HRUBÁ, Karolína January 2018 (has links)
The first part of my thesis is focused on observation of the leaf damage by invertebrate herbivores during season. I examined how the selected traits affect the palatability of plant species. In the next project, I investigated the effect of herbivory and gaps on seedling establishment. And finally, in the last part, I studied the effect of herbivory of terrestrial gastropods on competitive relationships among selected species.
87

War machines of the charitable city : fundraising and the architecture of territory in Paris

Franklin, Rosalind Ethelline January 2018 (has links)
This dissertation explores the entangled territorialities of charitable fundraising, redressing the under-theorisation of the praxis as a social construct and a transformative spatial process. It approaches fundraising from an etiological perspective, drawing on French continental theory, particularly the work of Michel Serres and of Deleuze and Guattari, as well as concepts arising from literature in relational geographies and in business studies. Unlike many scholarly accounts, which obscure the fact that this property-challenged, property-desiring practice relies on the hospitality of others in order to extract and transfer resources, this study argues that the trait of interloping is crucial to fundraising’s expansive colonisation of urban space. Seizing on the notions of minor architecture and itinerant territoriality, it thinks through fundraising’s habits, inhabitations and habitats. By doing so, it reveals a form of nomadic war machine specialised in crafting parasitic architectures that invade urban territories to constitute a territory of its own. That this state-authorised territory has become an obligatory passage point within contemporary networked societies says much about how power is forged through the intersection of political, moral-economic and socio-affective parameters. Moreover, in uncovering a hint of revanchism against the property-owning classes, this research points to the usual affective politics emerging at a time of state metamorphosis and protracted economic uncertainty. This conceptual work provides entry for an ethnographic exploration of the charitabilisation of urban life within the context of austerity in contemporary Paris. Evidence collected from interviews, participant observation, video, photography, maps, drawings and extant literature is used to illuminate fundraising’s polydimensional strategies and widespread yet minimally disruptive appropriations and expropriations. While other authors have documented the movement of fundraising in France from utter marginalisation to mainstream to strategic importance, this study traces the political and territorial machinations of the powerful Parisian network of non-profit leaders, association executives, heads of fundraising agencies, management consultants, lawyers, and government officials who lead the push for a more generous France. The continuities, tensions, and contradictions between this group’s production of space and the realities of on-the-street fundraising are explored through a series of case studies. The views presented highlight ways in which fundraisers induce and take advantage of breaches in prevailing articulations of space, time and citizen-bodies to fortify more-than-capitalist urban logics. Collectively, they render visible the temporalities, hotspots, technologies, imaginaries, schemes, and hypocrisies informing an aggressive incrementalism. The new view of Paris imparted foregrounds the enterprising, contested and geographically uneven process of cultivating the habit of ceding property, both in the sense of subjectivities and of material rights. This dissertation’s conceptual and empirical strands make it possible to apprehend how minoritarian actors become dominant. Extending the minoritarian’s right to temporally hold power and property is shown to involve continuously testing and exploiting the affordances of relations. Displayed and analysed are the contamination of ideals and the breaking of pacts within fundraising’s moral pursuit of wealth transference. Such promiscuities ought to be regarded as, this study emphasizes, a form of preparedness for the city to come.
88

Pós-efeitos da sincronização em campo e a fase de atividade do roedor subterrâneo tuco-tuco (Rodentia: Ctenomyidae) / Aftereffects of field entrainment and the activity phase of the subterranean rodent tuco-tuco (Rodentia: Ctenomyidae)

Barbara Mizumo Tomotani 09 December 2011 (has links)
Os tuco-tucos de Anillaco (Ctenomys cf. knighti) são roedores subterrâneos noturnos quando colocados em ciclo claro-escuro no laboratório. Com o interesse de se investigar o quanto um animal subterrâneo se expõe à luz, foi realizado um experimento de observação contínua em campo durante as horas claras do dia. Três indivíduos, um em cada estação, foram observados em uma arena semi-natural. Essas observações revelaram que os tuco-tucos não apenas saíam freqüentemente durante as horas claras do dia, como também apresentavam atividades robustas de forrageamento e remoção de terra de seus túneis. Uma vez que não se tinha conhecimento da atividade abaixo da terra ou durante à noite, foram examinados os pós-efeitos do arrastamento em campo para se investigar se o ritmo estaria sincronizado em campo e o quanto da atividade observada correspondia à atividade total do animal. Os pós-efeitos foram acessados pela transferência dos animais observados diretamente da arena para condições constantes. Surpreendentemente os animais exibiram uma atividade robusta concentrada na fase correspondente à noite ambiental sem transientes e sem traços da atividade diurna previamente observada em campo. Esse padrão foi observado em outros 10 animais trazidos dessa vez diretamente do campo e colocados em condições constantes. Além disso, não foram observadas diferenças na fase de atividade de animais com e sem acesso a rodas de atividade. Portando, nosso estudo com esses animais subterrâneos pode contribuir com elementos ecológicos nas discussões recentes sobre o significado da atividade diurna em animais que são noturnos segundo a fase do oscilador / South American subterranean rodents (Ctenomys cf. knighti), commonly known as tuco-tucos, display robust, nocturnal, wheel-running rhythms under a light-dark condition. To verify whether these subterranean and nocturnal animals ever expose themselves to light in the field, individual animals were continuously observed during light hours in a semi-natural enclosure that was constructed in their natural habitat. Observations during different seasons revealed that tuco-tucos not only emerged aboveground during daylight hours but also that their light exposure was due to robust diurnal activities of foraging and soil removal. Because of the lack of access to these animals´ subterranean and nocturnal activities in the field, the aftereffects of field entrainment were examined instead to verify the contribution of the previously observed diurnal behaviors to the total daily activity. This examination was achieved by transferring the observed animals from a field enclosure to constant laboratory conditions. Surprisingly, tuco-tucos exhibited robust activity concentrated in the phase corresponding to the external night without any trace of transients or of the diurnal activity that was observed in the enclosure. This pattern was also replicated when the aftereffects of the field entrainment of other animals trapped directly from the field were measured in the laboratory. Furthermore, no difference was detected in the activity measured with and without access to a running wheel. Our study of a wild subterranean species in its natural habitat can contribute novel ecological elements to the recently debated issue of the meaning of day-activity displayed by nocturnal rodents in the field
89

Visualising Interval-Based Simulations

Pawlik, Amadeusz, Andersson, Henry January 2015 (has links)
Acumen is a language and tool for modeling and simulating cyber-physical systems. It allows the user to conduct simulations using a technique called rigorous simulation that produces results with explicit error bounds, expressed as intervals. This feature can be useful when designing and testing systems where the reliability of results or taking uncertainty into account is important. Unfortunately, analyzing these simulation results can be difficult, as Acumen supports only two ways of presenting them: raw data tables and 2D-plots. These views of the data make certain kinds of analysis cumbersome, such as understanding correlations between variables. This is especially true when the model in question is large. This project proposes a new way of visualising rigorous simulation results in Acumen. The goal of this project is to create a method for visualising intervallic values in 3D, and implement it in Acumen. To achieve that, every span of values is represented as a series of overlapping objects. This family of objects, which constitutes an under-approximation of the true simulation result, is then wrapped inside a semi-translucent box that is a conservative over-approximation of the simulation result. The resulting implementation makes for a combination of mathematical correctness (rigour), and mediation of intervals in question. It enables the user to explore the results of his rigorous simulations as conveniently as with the existing, non-rigorous simulation methods, using the 3D visualisation to simplify the study of real-life problems. To our knowledge, no existing software features visualisation of interval-based simulation results, nor is there any convention for doing this. Some ways in which the proposed solution could be improved are suggested at the end of this report
90

Contribution au développement de modèles circuits pour l’étude de couplages électromagnétiques à l’intérieur d’enceintes métalliques / Contribution to the development of circuits models for the study of electromagnetic couplings inside metallic enclosures

Boutar, Abdelghafour 29 October 2014 (has links)
La prédiction du couplage d’interférences électromagnétiques avec les systèmes électroniques sensibles situés dans des enceintes blindées est devenue une nécessité dans le domaine de la compatibilité électromagnétique (CEM) des systèmes complexes. L’étude du couplage d’un champ ÉM avec et à l’intérieur de l’enceinte d’un équipement électronique a été réalisée antérieurement en utilisant des méthodes numériques et analytiques. Le travail de recherche présenté tout au long de ce document de thèse à pour but d’apporter une contribution à une meilleure compréhension des modèles analytiques permettant d’évaluer rapidement les niveaux de couplages induits sur un équipement électronique, en représentant celui-ci sous forme d’une enceinte métallique qui contient des monopôles, des dipôles, des plans de masse représentatifs de cartes et des lignes de transmissions. Après avoir établi le modèle physique de la fonction de Green (FG) relative à une cavité rectangulaire, la première partie à été consacrée à l’étude du couplage ÉM à l’intérieur d’une enceinte métallique rectangulaire en employant les modèles ILCM (Intermediat Level Circuit Model). Dans la deuxième partie de ce document, nous avons exploité le modèle ILCM pour l’étude du couplage ÉM avec des structures filaires de petite dimension. Afin d’étudier le couplage ÉM avec une ligne de transmission (LT) située à l’intérieur de l’enceinte d’un équipement électronique, nous avons développé au cours de la dernière partie de ce manuscrit un nouveau modèle du couplage. Différentes configurations ont été analysées, les résultats obtenus par ces analyses ont été comparés et validés avec Temsi-FD et avec les mesures expérimentales. / He electromagnetic interferences (EMI) coupling inside metallic cavities that constitutes the shielding of electronic cards is an important problem in the electromagnetic compatibility (EMC) domain. The electromagnetic (EM) coupling with transmission lines (TL) or other objects located inside an enclosure has been investigated by different authors. Previous analyses have been made using numerical and analytical methods. The goal of the research work presented in this manuscript is to make a contribution to a better understanding of the analytical models allowing to predict the EM coupling level induced on an electronic device. After the establishment the physical model for the modal representation of the Green function (GF), the first part is devoted to analyse the EM coupling within enclosure by using the ILCM (Intermediat Level Circuit Model) technique. In the second part of this manuscript, we have exploited the ILCM model for predicting the EM coupling with elementary antennas fixed within enclosure. Finally, in the last part, a simple and efficient analytical model has been developed for the prediction of the electromagnetic (EM) field coupling with a lossless transmission line (TL) located in a rectangular enclosure. The analytical results have been successfully compared over a wide frequency band with Temsi-FD and experimental results.

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