Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

Thesis (M.S.)--University of Alabama at Birmingham, 2008. / Title from PDF of title page (viewed July 24, 2009). Includes bibliographical references (p. 129-138).

Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 126-130).

Sous conditions de fort déséquilibre thermodynamique, les populations des états internes émettant dans le VUV et l’infrarouge ne suivent plus une distribution de Boltzmann mais sont contrôlés par des processus collisionels et radiatifs. Nous avons développé un nouveau modèle collisionel-radiatif (CR) comprenant les mécanismes d’excitation et d’ionisation par impact d’électrons et de particules lourdes, ainsi que les transitions radiatives. Une revue exhaustive des diverses données expérimentales et théoriques nous a conduit à sélectionner les formulations les plus appropriées. Les transitions radiatives on été traitées via le concept de facteur d’échappement, égal à 0 pour les transitions dans le VUV, et à 1 pour les transitions dans l’infrarouge, en accord avec les récents calculs de la littérature. Nous avons interfacé notre modèle CR avec un code d’écoulement et un code spectral en vue de prédire les luminances récemment mesurées dans le tube à choc EAST de la NASA. Nous avons choisi deux conditions représentatives d’une rentrée hypervéloce sur Terre: V∞=10.6 et 11.12 km/s, à pression p∞=13.3 Pa. Nous avons comparé les densités d’électrons prédites par le modèle d’écoulement avec celles extraites des caméras CCD et avons obtenu un excellent accord, validant de fait le modèle d’ionisation et nous permettant de déterminer la position du choc. Ensuite, nous avons comparé les profils de luminance prédits par le modèle CR mesurés dans le VUV et l’infrarouge avec les données expérimentales et avons obtenu un excellent accord. Nous avons ainsi montré que les collisions par impact de particules lourdes sont cruciales et doivent être déterminés précisément en vue de prédire le flux radiatif dans le VUV, lequel peut représenter 60% du flux total reçu par le vaisseau spatial lors de sa rentrée dans l’atmosphère terrestre. / Under nonequilibrium, the populations of the electronic states that strongly radiate in the VUV and IR are no longer governed by a Boltzmann distribution but rather by collisional and radiative processes. A new collisional-radiative (CR) model was developed including the key processes chief among them electron-impact excitation and ionization, heavy-particle impact excitation and bound-bound transitions. A comprehensive review of the available experimental and theoretical reaction rates governing these processes was undertaken to produce a reliable set of rates. The bound-bound radiative mechanisms were treated using the escape factor concept, set to zero for VUV lines and set to one for infrared lines, in accordance with literature results. The CR model was interfaced with the a flowfield solver and with a radiation code to predict the nonequilibrium VUV and IR radiation spectra very recently measured in the EAST facility at NASA Ames Research Center. Two shock-tube conditions representative of a Lunar return reentry trajectory were selected: V∞=10.6 and 11.12 km/s, both at p∞=13.3 Pa. The electron number density profiles inferred from experiments were compared with the prediction of the flowfield model, showing excellent agreement in trend and absolute magnitude for both freestream conditions, and thus validating the ionization model and providing a way to accurately locate the shock front in the CCD images. Then, the experimental intensity profiles were compared with the prediction of the CR model. Excellent agreement between predicted and measured intensity profiles was obtained for both freestream conditions, when adjusting the heavy-particle impact excitation rate constants of Park (1985), suggesting that the nonequilibrium peak intensities observed in the VUV and IR spectral ranges are controled by heavy-particle impact processes.

Nesta tese investigamos modelos irreversíveis dentro do contexto da mecânica estatística de não-equilíbrio motivados por alguns problemas de dinâmicas de populações biológicas. Procuramos identificar a existência de transições de fase e as classes de universalidade às quais os modelos pertencem. Além disso, buscamos modelos que capturem as principais características dos sistemas biológicos que procuramos descrever. Encontramos a solução analítica exata para o modelo suscetível-infectado-recuperado (SIR) em uma rede unidimensional. Investigamos o modelo suscetível-infectado-recuperado com infecção recorrente. Mostramos que o modelo pertence à classe de universalidade da percolação isotrópica, salvo pelos parâmetros em que se torna o processo de contato. Obtivemos também a linha de transição entre as fases em que há e não há propagação da epidemia, através de aproximações de campo médio e por simulações de Monte Carlo do modelo na rede quadrada. Investigamos uma dinâmica para duas espécies biológicas e dois nichos ecológicos; para tanto introduzimos um modelo estocástico irreversível de quatro estados. Concluímos que o modelo oferece uma descrição para as oscilações temporais das populações das espécies e para a alternância de dominância entre estas. Para chegar a esta conclusão, utilizamos simulações de Monte Carlo do modelo na rede quadrada, aproximações de campo médio e a abordagem da equação mestra de nascimento e morte, a qual, para grandes populações, pode ser aproximada por uma equação de Fokker-Planck que é associada a um conjunto de equações de Langevin. Por fim, usando simulações de Monte Carlo, analisamos a dinâmica de duas espécies biológicas e dois nichos ecológicos incluindo difusão. Novamente verificamos que o modelo gera cenários com oscilações temporais das populações das espécies e alternância de dominância entre estas. Ademais, concluímos que modelo pertence à classe de universalidade da percolação direcionada e obtivemos o diagrama de fase. / In this thesis we investigate irreversible models within the context of nonequilibrium statistical mechanics motivated by some problems of biological population dynamics. We look for dentifying the existence of phase transition and the universality classes to which the models belong. In addition to that, we look for models that capture the main characteristics of the biological systems which we are interested in describing. We found the exact analytic solution of the susceptible-infected-recovered (SIR) model on one-dimensional lattice. We investigated the susceptible-infected-recovered model with recurrent infection. We showed that the model belongs to the isotropic percolation universality class, except for the parameters that make the model become a contact process. We obtained the transition line between the phases in which there is propagation of the epidemic and in which there is not, by means of mean-field approximations and Monte Carlo simulations on a square lattice. Furthermore, we investigated a dynamic for two biological species and ecological niches; for this purpose we introduced an irreversible stochastic model with four states. We conclude that the modoffers a description of time oscillations of the species populations and of the alternating dominance between them. To achieve this conclusion we used Monte Carlo simulations of this model on a square lattice, mean-field approximation, and the birth and death master equation approach, which for large populations can be approximated by a Fokker-Planck equation that is associated to a set of Langevin equations. Finally, using Monte Carlo simulations, we analyzed a dynamic for two biological species and ecological niches including diffusion. Again, we verified that the model generates scenarios with time oscillations of the species populations and with alternating dominance between them. Also, we conclude that the model belongs to the directed percolation universality class and we found the phase diagram.

Adaptive governance must work "on the ground," that is, it must operate through structures and procedures that the people it governs perceive to be legitimate and fair, as well as incorporating processes and substantive goals that are effective in allowing social-ecological systems (SESs) to adapt to climate change and other impacts. To address the continuing and accelerating alterations that climate change is bringing to SESs, adaptive governance generally will require more flexibility than prior governance institutions have often allowed. However, to function as good governance, adaptive governance must pay real attention to the problem of how to balance this increased need for flexibility with continuing governance stability so that it can foster adaptation to change without being perceived or experienced as perpetually destabilizing, disruptive, and unfair. Flexibility and stability serve different purposes in governance, and a variety of tools exist to strike different balances between them while still preserving the governance institution's legitimacy among the people governed. After reviewing those purposes and the implications of climate change for environmental governance, we examine psychological insights into the structuring of adaptive governance and the variety of legal tools available to incorporate those insights into adaptive governance regimes. Because the substantive goals of governance systems will differ among specific systems, we do not purport to comment on what the normative or substantive goals of law should be. Instead, we conclude that attention to process and procedure (including participation), as well as increased use of substantive standards (instead of rules), may allow an increased level of substantive flexibility to operate with legitimacy and fairness, providing the requisite levels of psychological, social, and economic stability needed for communities to adapt successfully to the Anthropocene.

Orientadores: Marcus Vinícius Segantini Bonança, Maurice de Koning / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin / Made available in DSpace on 2018-08-27T07:13:33Z (GMT). No. of bitstreams: 1 Acconcia_ThiagoVaz_M.pdf: 3294549 bytes, checksum: 001cb3dfa8e23080664b78fe7e5f527d (MD5) Previous issue date: 2015 / Resumo: A termodinâmica é uma teoria do calor e trabalho, a qual descreve perfeitamente os processos quase-estáticos somente. Entretanto, além dos estados de equilíbrio, nós encontramos uma ampla classe de processos operando em tempo finito. Uma meta onipresente na termodinâmica é a otimização dos processes a tempo finito através da minimização do trabalho dissipado ou trabalho em excesso. Para o oscilador harmônico paramétrico, nós derivamos uma família altamente degenerada de protocolos ótimos a tempo finito, ao longo dos quais o trabalho em excesso produzido se anula exatamente. Para isso, o sistema de interesse se mantém termicamente isolado durante todo o processo de atuação do protocolo de switching. Esses protocolos ótimos são obtidos através da teoria de resposta linear para sistemas inicialmente preparados segundo uma distribuição canônica. Para sistemas com um grau de liberdade, mostramos evidências de que esses caminhos ótimos podem também levar à conservação do invariante adiabático correspondente. Além dos resultados analíticos para os osciladores harmônicos clássico e quântico, nós apresentamos resultados numéricos para alguns exemplos anarmônicos. Finalmente, nós reformulamos os resultados anteriores quantificando-os em termos do comprimento termodinâmico para a versão quântica do sistema oscilador harmônico / Abstract: Thermodynamics is a theory of heat and work, which describes perfectly only the quasistatic processes. However, if we shift our view away from the equilibrium states, we find a wide class of processes operating in finite-time. An ubiquitous goal in thermodynamics is to optimize the finite time processes by minimizing the dissipated or excess work. For the parametric harmonic oscillator, we derive a family of degenerated finite-time optimal protocols for which the excess work during a non-equilibrium process vanishes exactly. For this, the system of interest is kept thermally isolated during the switching of a control parameter. These optimal paths are obtained within linear response for systems initially prepared in a canonical distribution. For systems with one degree of freedom, we claim that these optimal paths may also lead to the conservation of the corresponding adiabatic invariant. Besides the analytical results for both classical and quantum harmonic oscillator, we present numerical results for certain anharmonic examples. Finally, we discuss the reformulation of the latter results terms of the thermodynamic length for the quantum version of the harmonic oscillator system / Mestrado / Física / Mestre em Física

京都大学 / 新制・課程博士 / 博士(理学) / 甲第22988号 / 理博第4665号 / 新制||理||1669(附属図書館) / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)教授 柳瀬 陽一, 教授 田中 耕一郎, 教授 石田 憲二 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

Gaseous pollution has become a global issue and its presence above certain limits is hazardous to human health and environment. Detection of such gases is an immediate need and researchers around the world are trying to solve this problem. Metal oxides are being used as sensing materials for a long time, but a high operating temperature limits applications in many areas. On the other hand, two-dimensional (2D) materials with high surface-to-volume ratio and chemical stability are promising candidates in the field of gas sensing. This includes monolayer transition metal dichalcogenides, such as MoS2 and WS2, which are direct band gap materials. While few layer transition metal dichalcogenides are indirect band gap materials, they are easier to synthesize than monolayers. Therefore, it is important to understand whether few layer transition metal dichalcogenides possess the same sensing behavior as the corresponding monolayers. For this reason the first part of this dissertation compares the sensing behavior of monolayer and few layer MoS2 and WS2. Two dimensional hexagonal boron nitride is a highly stable structural analogue of graphene. However, its insulating behavior with large band gap is not suitable for sensing. Recently, monolayer Si2BN has been proposed to exist. As the presence of Si makes this material reactive, the second part of this dissertation addresses its application as sensing material. In the _nal part of this dissertation, in search of a metal free, non-toxic, and earth abundant sensor material, further structural analogues of graphene are considered, namely monolayer C3N, monolayer C3Si, and monolayer C6BN. In particular, different theoretical approaches for studying the sensing performance of materials are compared to each other.

京都大学 / 新制・課程博士 / 博士(理学) / 甲第23450号 / 理博第4744号 / 新制||理||1680(附属図書館) / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)教授 早川 尚男, 教授 佐々 真一, 教授 川上 則雄 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM