Thesis (M. Eng.)--Carleton University, 1992. / Also available in electronic format on the Internet.

Thesis (Ph. D.)--Princeton University, 1995. / Includes bibliographical references.

Thesis (Ph. D.)--University of Queensland, 2000. / Includes bibliographical references.

L’intérêt grandissant suscité par l’utilisation de l’hydrogène en tant que vecteur énergétique a mis en évidence un besoin de données fiables concernant les explosions de mélanges hydrogène-air dans des milieux obstrués et/ou confinés. C’est pourquoi, après une analyse poussée de la littérature, le travail de thèse présenté dans ce mémoire s’est focalisé sur l’accélération de flamme hydrogène-air dans de tels milieux. L’objectif est de proposer une base de données concernant la surpression maximale et la vitesse de flamme maximale dans le cas d’une déflagration de mélange hydrogène-air. Pour parvenir à cet objectif, différentes séries d’expériences menées à l’échelle du laboratoire ont été réalisées. Les séries d’essais entreprises se sont ainsi déroulées selon trois phases : i) validation du dispositif d’acquisition des mesures en utilisant une charge hémisphérique hydrogène-air, ii) essais en milieu obstrué et non confiné, et iii) essais en milieu confiné et obstrué. Les obstacles choisis pour cette étude se présentent sous la forme de couches de grillage ou de plaque. Dans les structures obstruées ainsi créées, la taille de maille, la forme de la maille, la position des différentes couches et l’espace entre couches varient. Ces essais ont notamment montré que des mailles carrées engendraient une surpression plus importante que des mailles rondes dans le cadre d’obstacles de type plaque. Une comparaison des résultats expérimentaux avec ceux obtenus par application des modèles de la littérature a été établie. Cette comparaison porte sur le calcul de la vitesse de flamme maximale en milieu obstrué et le calcul de la surpression maximale en milieu confiné. / The increasing interest created by the use of hydrogen as an energy carrier has underlined a need of reliable data concerning hydrogen-air explosions in obstructed and/or confined area. That’s why, after a detailed literature review, the study presented in this dissertation focused on hydrogen-air flame acceleration in obstructed and/or confined area. The aim of this study is to propose a data base concerning maximal overpressure and maximal flame speed in the case of hydrogen-air deflagration. To achieve this goal, different series of laboratory scale experiments have been realized. The experiments have been performed in three steps: i) validation of measurement set up with hemispherical hydrogen-air charge, ii) experiments in obstructed and unconfined area, and iii) experiments in confined area. The obstacles chosen in this study are layers of wire mesh or plate. In this obstructed structure, the mesh size, the mesh shape, the place of two consecutive layers and the pitch between two consecutive layers can vary. These experiments have notably shown that the square meshes generated more important overpressures than circular meshes in the case of plate obstacles. A comparison has been performed between experimental measurements and results given by the use of analytical models found in literature relations. The comparison was done for the maximal flame speed in obstructed area, and the maximal overpressures in confined area.

During the course of the last decade successive governments in the UK have placed young people’s aspirations at the core of their attempts to address poor outcomes within the education system and the labour market. An area-based approach to policy has come to the fore which links ‘low aspirations’ with particular community- and neighbourhood-level factors, in particular area-level deprivation. This area-based focus on the determinants of aspirations has faced intensifying critique from the academic research base. Responding to this policy and research debate, this thesis examines whether, and how, young people’s occupational aspirations are shaped by the areas they live in. The thesis is based on a mixed methods research design and has two sections: an extensive phase and an intensive phase. The extensive phase of the research consists of logistic regression analysis of data from the Understanding Society Youth Questionnaire, and considers whether the types of occupations young people aspire to vary between different types of area. The intensive phase of the research consists of phenomenographic analysis of semi-structured interviews conducted with young people in a deprived, outer-urban neighbourhood in Manchester, and considers how young people’s subjective orientations towards the area they live in produce different forms of aspiration. The thesis finds compelling evidence that young people’s occupational aspirations are shaped by the areas they live in, but does not corroborate the claim at the core of current government policy, that aspirations are lower in more deprived areas. The extensive phase of the research instead identifies area type, rather than deprivation, as the primary area-level factor shaping young people’s aspirations, with young people from particular inner city area types almost five times as likely as their peers from deprived outer-urban areas to aspire to ‘higher’ professional, managerial and technical occupations. Meanwhile, the intensive phase of the research finds evidence that experiences of neighbourhood and family life in an area of concentrated deprivation can lead young people to adopt particular forms of aspiration that require lower levels of skill and further training, but on closer examination of the motivations for these forms of aspiration, finds little evidence that these aspirations are straightforwardly ‘low’. Above all, the research demonstrates that young people produce multiple different senses of place, and myriad forms of aspiration, from within the same deprived spatial context: they do not simply reproduce what they see around them when imagining their futures. While there is compelling evidence that young people’s occupational aspirations are shaped by the areas they live in, these area effects demand more nuanced research alongside policy approaches that are more receptive to young people’s constructions of place.

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Recent studies and research demonstrate the importance of play and play-based learning. There are many articles that have shown that play is an essential component of a child's development. Play-based learning is even more important for children with disabilities. Without play, special needs children may develop learning deficits that complicate the disabilities they are already experiencing. The benefits of play are inextricably related to the environments in which it occurs. Play environments need to be carefully designed to ensure that children are able to realize the full benefits of play. In the United States, public play areas are abundant. However, do these play areas stimulate the development of children? Have they been designed to be inclusive to those with special needs? The need to have play areas that are truly accessible is further amplified by recent statistics, which show that there is an upward trend in the number of U.S. students with disabilities. Consequently, there is a significant need for play spaces that are stimulating and inclusive to children of all abilities. This paper highlights the importance of play, play environments, and disability play. It provides an overview of disabilities in children and their effects on play. It critically examines the current state of play in America. Based on literature review, historical information, and critical analyses of existing play areas, this paper advocate for nature-based playgrounds. Through the design of a play landscape that is nature-based and inclusive to children with Autism, this paper demonstrates significant advantages of nature-based inclusive play space design and advocates for such play spaces over traditional play spaces designed with man-made materials. / Master of Landscape Architecture / Play is often dismissed as something that children engage in when they are young. Play is actually extremely important to a child’s development. Play contributes to physical, cognitive, emotional, and social well-being of children. This paper highlights the importance of play for all children, including those with disabilities, and underscores the significance of a well-designed play environment in a child’s development. Play areas are abundant in the United States. The goal of this research is to understand whether such play areas are designed to help children realize the full benefits of play, and whether such play areas are inclusive and accessible for children with disabilities. Given the rising prevalence of autism in children, a nature based playground design that is inclusive for children with Autism is presented in this paper. The framework and design considerations presented here can be replicated to any generic play site to create a much more stimulating and inclusive play environment.