Zugl.: München, Techn. Univ., Diss., 2009

Considere o problema de valor inicial e de fronteira \'u IND.t\'= \'delta\'u + f(u) em \'ômega\' x (0, T), u(x, 0) = \'fi\'(x) se x \'PERTENCE A\' \'ômega\', u(x, t) = 0 se x \'PERTENCE A\' \'delta\' \'ômega\', 0 < t < T, onde ­\'ômega\' é um domínio limitado em \'R POT.n\'com bordo \'C POT.2\', f é continuamente diferenciável com f(s) > 0, e \'fi\' é não-negativa e suave sobre \'ômega\'\'BARRA\' com \'fi\'=0 sobre \'delta\'\'ômega\'. Suponha que a única solução u(x,t) possui blow-up em tempo finito T < \'INFINITO\'. A questão que se coloca é: onde ocorre o blow-up? Neste trabalho provamos que: se \'ômega\'=\'B IND.R\'\'ESTÁ CONTIDO EM\'\'R POT. n\', então o blow-up ocorre apenas em r=0, Além disso, se f(u)=\'u POT.p\'p > 1, então u(r,t)\'< OU = \'C/\'r POT.2\'(\'gama\'-1) para qualquer 1 < \'gama\'< p, e assim \'limsup IND. t\'SETA\'T\'-||u(u.\'t)||q < \'INFINITO\'se q < n(p-1)/2. No caso não simétrico onde \'ômega\' é um domínio complexo, provamos que conjunto de blow-up é um subconjunto compacto de \'ômega\'. Se f(u)=\'u POT.p\', p > 1, então u(x,t)\'< OU = \'C/\'(T-t) POT. 1/p-1\' e, se n=1,2 ou se n\'< OU=\'3 p\'< OU=\'(n+2)/(n-2), então \'tau\'POT. \'beta\'u(x+\'Ksi\', T-\'tau\'\'SETA\'\'C IND. 0\' quando \'tau\'\'SETA\'\'0 POT. 1/2\'e \'C IND. 0\'= \'beta\'POT.\'beta\'\'onde \'beta\'= \'(p-1) POT. -1\'. As provas das estimativas essenciais para demonstração desses resultados são feitas utilizando o Princípio do Máximo / Consider the initial-boundary value problem \'u IND.t\'= \'delta\'u + f(u) in \'ômega\' x (0, T), u(x, 0) = \'fi\'(x) if x \'BELONGS\' \'ômega\', u(x, t) = 0 if x \'BELONGS \' \'\\PARTIAL\' \'ômega\', 0 < t < T, where ­\'ômega\' is a bounded domain in \'R POT.n\'with \'C POT.2\', f is continuously differentiable with f(s) > 0, and \'fi\' is nonnegative and smooth on \'ômega\'\'BARRA\' with \'fi\'=0 on \'\\PARTIIAL\'\'ômega\'. Assume that the unique solution u(x,t) blows up in finite time T < \'INFINITO\'. The question addressed is: where does the blow-up occur? In this work we prove: if \'ômega\'=\'B IND.R\'\'IS CONTAINED EM\'\'R POT. n\', then blow-up occurs only at r=0, Moreover, if f(u)=\'u POT.p\'p > 1, then u(r,t)\'< OU = \'C/\'r POT.2\'(\'gama\'-1) for any 1 < \'gama\'< p, and hence \'limsup IND. t\'SETA\'T\'-||u(u.\'t)||q < \'INFINITO\'se q < n(p-1)/2. In the nonsymmetric case where \'ômega\' is a convex domain, we prove that the blow-up set lies in a compact subset of \'ômega\'. If f(u)=\'u POT.p\', p > 1, then u(x,t)\'< OU = \'C/\'(T-t) POT. 1/p-1\' and, if n=1,2 or if n\'< OU=\'3 and p\'< OU=\'(n+2)/(n-2), then \'tau\'POT. \'beta\'u(x+\'Ksi\', T-\'tau\'\'SETA\'\'C IND. 0\' where \'tau\'\'SETA\'\'0 POT. 1/2\'e \'C IND. 0\'= \'beta\'POT.\'beta\'\'where \'beta\'= \'(p-1) POT. -1\'. Elementary applications of the Maximum Principle are used to prove the essential estimate for the proofs of these results.

New software products, especially those based on innovation, typically originate in startup environment. The reasons are well -- known: small start-ups are quick to market (as marketing and development are close, sometimes one person), able to take decisions quickly, not risk-averse, unburdened by corporate bureaucracy etc. If successful (as they all hope to be), they grow quickly. Here comes the catch -- the same attributes that contributed to success early on can become reasons to fail later. The methods used by few, highly motivated stakeholders (owners/managers, key employees) at the beginning do not support the project organization as more people and complex issues are involved. This transition is the subject of this thesis -- how to make sure that suitable methods to support the alignment of marketing and development are phased in not too early (when they would constitute a drag and straitjacket, robbing the start-up of its advantages) but not too late (when their absence would lead to inconsistencies and mistakes, preventing the start-up to become a mature operation). As each project is unique, it requires different method at different times. Rather than proposing a fixed methodology, the thesis suggests criteria for recognizing when to look for a suitable method, how to choose it and how to apply it with minimum effort and optimum result. The theoretical part of the thesis explains how the methods work, the practical part demonstrates how they contribute to making correct decisions with higher probability.

Considere o problema de valor inicial e de fronteira \'u IND.t\'= \'delta\'u + f(u) em \'ômega\' x (0, T), u(x, 0) = \'fi\'(x) se x \'PERTENCE A\' \'ômega\', u(x, t) = 0 se x \'PERTENCE A\' \'delta\' \'ômega\', 0 < t < T, onde ­\'ômega\' é um domínio limitado em \'R POT.n\'com bordo \'C POT.2\', f é continuamente diferenciável com f(s) > 0, e \'fi\' é não-negativa e suave sobre \'ômega\'\'BARRA\' com \'fi\'=0 sobre \'delta\'\'ômega\'. Suponha que a única solução u(x,t) possui blow-up em tempo finito T < \'INFINITO\'. A questão que se coloca é: onde ocorre o blow-up? Neste trabalho provamos que: se \'ômega\'=\'B IND.R\'\'ESTÁ CONTIDO EM\'\'R POT. n\', então o blow-up ocorre apenas em r=0, Além disso, se f(u)=\'u POT.p\'p > 1, então u(r,t)\'< OU = \'C/\'r POT.2\'(\'gama\'-1) para qualquer 1 < \'gama\'< p, e assim \'limsup IND. t\'SETA\'T\'-||u(u.\'t)||q < \'INFINITO\'se q < n(p-1)/2. No caso não simétrico onde \'ômega\' é um domínio complexo, provamos que conjunto de blow-up é um subconjunto compacto de \'ômega\'. Se f(u)=\'u POT.p\', p > 1, então u(x,t)\'< OU = \'C/\'(T-t) POT. 1/p-1\' e, se n=1,2 ou se n\'< OU=\'3 p\'< OU=\'(n+2)/(n-2), então \'tau\'POT. \'beta\'u(x+\'Ksi\', T-\'tau\'\'SETA\'\'C IND. 0\' quando \'tau\'\'SETA\'\'0 POT. 1/2\'e \'C IND. 0\'= \'beta\'POT.\'beta\'\'onde \'beta\'= \'(p-1) POT. -1\'. As provas das estimativas essenciais para demonstração desses resultados são feitas utilizando o Princípio do Máximo / Consider the initial-boundary value problem \'u IND.t\'= \'delta\'u + f(u) in \'ômega\' x (0, T), u(x, 0) = \'fi\'(x) if x \'BELONGS\' \'ômega\', u(x, t) = 0 if x \'BELONGS \' \'\\PARTIAL\' \'ômega\', 0 < t < T, where ­\'ômega\' is a bounded domain in \'R POT.n\'with \'C POT.2\', f is continuously differentiable with f(s) > 0, and \'fi\' is nonnegative and smooth on \'ômega\'\'BARRA\' with \'fi\'=0 on \'\\PARTIIAL\'\'ômega\'. Assume that the unique solution u(x,t) blows up in finite time T < \'INFINITO\'. The question addressed is: where does the blow-up occur? In this work we prove: if \'ômega\'=\'B IND.R\'\'IS CONTAINED EM\'\'R POT. n\', then blow-up occurs only at r=0, Moreover, if f(u)=\'u POT.p\'p > 1, then u(r,t)\'< OU = \'C/\'r POT.2\'(\'gama\'-1) for any 1 < \'gama\'< p, and hence \'limsup IND. t\'SETA\'T\'-||u(u.\'t)||q < \'INFINITO\'se q < n(p-1)/2. In the nonsymmetric case where \'ômega\' is a convex domain, we prove that the blow-up set lies in a compact subset of \'ômega\'. If f(u)=\'u POT.p\', p > 1, then u(x,t)\'< OU = \'C/\'(T-t) POT. 1/p-1\' and, if n=1,2 or if n\'< OU=\'3 and p\'< OU=\'(n+2)/(n-2), then \'tau\'POT. \'beta\'u(x+\'Ksi\', T-\'tau\'\'SETA\'\'C IND. 0\' where \'tau\'\'SETA\'\'0 POT. 1/2\'e \'C IND. 0\'= \'beta\'POT.\'beta\'\'where \'beta\'= \'(p-1) POT. -1\'. Elementary applications of the Maximum Principle are used to prove the essential estimate for the proofs of these results.

La synthèse de graphène par approche « bottom-up » fait l’objet de nombreux travaux de recherche ayant pour but de contrôler les propriétés électroniques et optiques de ce matériau par la fabrication de nanostructures avec une précision atomique. D’autre part, le contrôle de dopant dans le graphène permettant d’en moduler les propriétés suscite un grand intérêt et dans ce contexte l’utilisation de porphyrines avec un taux d’azote contrôlé est attrayante. Par leurs ressemblances structurelles, les porphyrines π-étendues peuvent être considérées comme des nanoparticules de graphène dopées à l’azote (GQDs) présentant de fortes propriétés infrarouge tandis que les briques de construction à base de porphyrines peuvent être utilisées pour la synthèse sur surface de deux type de nanoarchitectures de graphene appélées nanorubans (GNRs) et nanomèches (GNMs). Cette thèse a pour objectif de développer la synthèse de porphyrines à base d’anthracenes et de les utiliser comme précurseurs pour la fabrication de nanostructures. La première partie de cette thèse est dédiée à la synthèse organique de différentes anthracenylporphyrines et à l’étude de leurs assemblages sur surface dans la chambre d’un microscope à effet tunnel. La seconde partie est dédiée à l’étude de formation de porphyrines π-étendues via une méthode pyrolyse flash pouvant activer thermiquement des réactions de couplage par déhydrogenation entre des hydrocarbures aromatiques polyycliques (PAHs) et des porphyrines. La dernière partie est dédiée à la modification post synthétique d’une tetrabromoanthracenylporphyrine par addition de PAHs via la réaction de couplage de Suzuki-Miyaura et à la caractérisation des propriétés optiques de ces porphyrines nouvellement formées. / The synthesis of graphene via bottom-up approach is a hot topic of research that aims to control the electronic and optical properties of this material by the fabrication of atomically precised nanostructures. Moreover, the control of dopant in graphene is of great interest to modulate the properties of the material. In this context, the contribution of porphyrins with a controlled content of nitrogen is attractive in this context. Because of structural similarities with graphene quantum dots (GQDs), π-extented porphyrins can be regarded as nitrogen-doped GQD with promising NIR properties. Porphyrins are convenient building blocks for the synthesis on surface of nanoarchitectures of graphene called nitrogen-doped Graphene Nanoribbons (GNRs) and Graphene NanoMeshes (GNMs). This thesis aims to develop the synthesis of symmetrical and robust porphyrins with anthracenes and to use them as precursors for the fabrication of nanostructures. The first part of this thesis is dedicated to the organic synthesis of variety of anthracenylporphyrins and the study of their assemblies on surface in a chamber of a Scanning Tunneling Microscope. The second part is dedicated to the study of formation of π-extended porphyrins via a method of flash pyrolysis able to thermally activate dehydrogenative coupling reactions between Polycyclic Aromatic Hydrocarbons (PAHs) and porphyrins. The last part is dedicated to the post synthetic modification of a tetrabromoanthracenylporphyrin with additional PAHs via Suzuki-Miyaura coupling and the characterization of the optical properties of the resulting porphyrins.

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This study examines the preparation during high school and post-secondary outcomes of students with disabilities. High school preparation consists of activities in which students participated during high school. Post-secondary outcomes relate to the current status of students following high school graduation in relation to the four major outcomes areas: (a) post-secondary education, (b) employment, (c) independent living, and (d) recreation and leisure. The target population included all students graduating from one school district in a mid-sized city in Texas. A stratified random sample of 228 students both with and without disabilities was selected. Post-secondary follow-up surveys, consisting of one survey administered prior to graduation and one survey administered six-months following graduation, were given to the participants. The response rate for the initial exit survey was 82.9% while the response rate for a post-school survey was 61.4%. Differences between groups were analyzed using loglinear analyses based upon educational setting, disability category, gender, ethnicity, and socio-economic status. In addition, a sub-study was completed to determine the level of agreement among students and teachers on a post-secondary readiness skill inventory. The findings indicated that differences among groups did exist in terms of both high school preparation and post-secondary outcomes. In terms of high school preparation, the participation among various groups produced few results that were significantly different. Statistically significant results occurred only with respect to extracurricular activity participation by educational setting and socio-economic status. Post-secondary outcome results produced more statistically significant findings than high school preparation. The variable of educational setting produced statistically significant post-secondary outcomes in the three areas of employment, post-secondary education, and recreation and leisure. Ethnicity was the next largest determinant to influence post-secondary outcomes, and statistically significant results were found for both post-secondary education and independent living. Socio-economic status produced statistically significant results for employment outcomes. The variable of gender produced no results that reached statistical significance. The last findings provided an analysis of the agreement between students and teachers in terms of a post-secondary readiness skill inventory. Overall students and teachers demonstrated a high level of congruency in which similar responses were indicated within 95% of the items.

An initial evaluation of the scalability of extrusion foaming technology is conducted in this thesis. Both lab- and pilot-scale foam extrusion systems along with annular dies and flat dies were used to investigate the effects of extrusion system scale on the foam expansion. The effects of the processing conditions including die temperature and blowing agent content on the volume expansion of extruded polystyrene foams blown with carbon dioxide are presented. A systematic comparison of the effects of extrusion system scale on the expansion behavior of polystyrene foams blown with carbon dioxide at the consistent pressure-drop rate, demonstrated that the scale of the foam extrusion system does not affect the principles of the foaming process, and the effects of extrusion system size on the scale-up of foam techniques, such as shear rate and temperature uniformity, could be suppressed by tailoring the processing conditions and experimental parameters.