<p dir="ltr">The Boeing-AFOSR Mach-6 Quiet Tunnel (BAM6QT) was used for a set of experiments aiming to characterize the stability regimes of stagnation point injection in noisy and quiet flow across an array of different injected gases. Four gases were used in this experiment: air, helium, carbon dioxide, and argon. These gases were injected at varying thrust coefficients, ranging from 0.0516 to 0.5666, using a 7 degree half-angle cone with a 19 mm radius spherical nose and a single 1.93 mm-radius sonic jet in the center of the model. The primary data collected consists of schlieren images gathered at a sample rate of 76 kHz. These data were then analyzed using a shock tracking software to measure the physical locations of flow features as well as through spectral proper orthogonal decomposition (SPOD) to analyze specific modes in the flow.</p><p dir="ltr">Through this analysis, it was observed that three principle modes exist in stagnation point injection regardless of the injecting gas: a high frequency vortex-coupled mode, a low frequency Mach-shock-rigid mode, and a hybrid mode residing between these two modes. The first two modes were observed in all stability regimes, whereas the hybrid mode was only observed in the bifurcated regime. Furthermore, the unsteady regime was observed to be mostly characterized by this first, vortex-coupled mode. Conversely, the steady regime was observed to be driven by the Mach-shock-rigid mode instead. This transition was measured to occur as the thrust coefficient was increased.</p><p dir="ltr">This research also found that freestream noise resulted in an amplified and widened frequency range within the Mach-shock-rigid mode. This same freestream noise did not appear to have an impact on the other two principle modes; however, in some cases the noise produced in the Mach-shock-rigid mode due to this freestream noise did in fact mask the other principle modes.</p><p dir="ltr">Lastly, it was observed that the thrust coefficient, in and of itself, is not the sole indicator of stability in stagnation point injection. Across the different injected gases in this research, transition between the stability regimes did not in fact occur at a constant thrust coefficient value. Additionally, even within the same injected gas, this transition did not occur at the same thrust coefficient value between noisy and quiet runs—indicating an effect of freestream noise on stability.</p>

[pt] Eu desenvolvo um modelo de ciclo de vida para avaliar a importância relativa de vários determinantes de londo prazo da taxa de juros. O modelo é uma generalização de Gertler (1999), incluindo imperfeições no mercado de crédito e heterogeneidade entre trabalhadores para capturar totalmente os efeitos da transição demográfica. O modelo é calibrado para a economia brasileira, incluindo perfis para os gastos do governo, gastos com previdência, dívida pública, crescimento da produtividade e variáveis demográficas. O modelo explica 71 porcento da variação total na taxa de juros brasileira entre 2000 e 2019. Fatores demográficos, especialmente aumentos na expectativa de vida, são os principais determinantes da queda nas taxas de juros reais. Essas forças são parcialmente compensadas por aumentos na dívida pública e nos gastos com previdência. Além disso, o arcabouço sugere que as taxas de juros reais continuarão caindo nos próximos 20 anos, atingindo o patamar de 1.5 porcento a.a., apesar de aumentos razoáveis na dívida pública. No entanto, possíveis efeitos de prêmios de risco e juros globais nas taxas de juros domésticas não são incluídos na análise. / [en] I develop a life cycle model to evaluate the relative importance of several long-term drivers of real interest rates. The model is a generalization of Gertler (1999), including credit market imperfections and heterogeneity among workers to fully capture the effects of the demographic transition. I calibrate the model to the Brazilian economy, feeding it with profiles for government spending, public debt, productivity growth and demographic variables. The model explains 71 percent of the overall change in real interest rates in Brazil between 2000 and 2019. Demographic factors, especially increases in life expectancy, are the key drivers of the fall in real interest rates. These forces are partially compensated by increases in public debt and social security spending. Moreover, the framework suggests that real interest rates will keep falling over the next 20, reaching a level of 1.5 percent despite reasonable increases in government debt. However, possible effects of risk premia and global rates on domestic interest rates are absent from the analysis.

Approved for public release, distribution is unlimited / Methods used for designing the ramjet included conic shock tables; isentropic flow tables and the GASTURB code was used for aerothermodynamic performance prediction. The flow field through the proposed geometry was computed using the OVERFLOW code, and small modifications were made. Geometry and solid models were created and built using SolidWorks 3D solid modeling software. A prototype ramjet was manufactured with wind tunnel mounting struts capable of measuring axial force on the model. Shadowgraph photography was used in the Mach 4 supersonic wind tunnel at the Naval Postgraduate School's Turbopropulsion Laboratory to verify predicted shock placement, and surface flow visualization was obtained of the airflow from fuel injection ports on the inlet cone of the model. All indications are that the cold-flow tests were successful. / Ensign, United States Naval Reserve

Estudos que enfocam fenômenos relacionados ao desenvolvimento local e à qualidade de vida em pequenas cidades ou pequenos municípios, ainda quando estes estão inseridos em regiões em processo de reestruturação produtiva e desenvolvimento local, se tornaram relevantes nos últimos anos. Dentre os problemas relacionados a esta temática, a migração das populações e crises do sistema produtivo rural que vem sendo abordados a partir das dimensões econômica, produtiva; das dinâmicas rural-urbano; da qualidade de vida e da governança urbana, são temáticas que servem para descrever e analisar problemas relacionados ao isolamento de pequenas cidades e seus efeitos sobre as redes urbanas regionais, centrados em fatores funcionais multidimensionais e multiescalares. No entanto, a dimensão espacial do fenômeno de isolamento e segregação de pequenas cidades não contemplam especificamente as configurações das redes regionais e os limites territoriais e espaciais impostos à integração regional e ao desenvolvimento local. O objetivo da pesquisa é relacionar as variáveis morfológicas e espaciais das configurações regionais a processos de estagnação social e econômica de pequenos municípios. O estudo de caso empírico é o município de Santa Tereza / RS, inserido na região de planejamento da Serra, recentemente incorporado à Região Metropolitana da Serra Gaúcha, cujo núcleo urbano foi designado pelo IPHAN como exemplar da Paisagem Cultural da Imigração Italiana no Brasil. No entanto, estas ações institucionais multiescalares não modificaram os padrões de desenvolvimento local, nem instigaram a adesão do município às transformações produtivas em curso no contexto regional. O município está, há cinquenta anos, num processo de estagnação econômica, perda de população e alheio às mudanças pelas quais passa a região em que se inscreve. Neste contexto, o problema é discutido a partir da dimensão espacial do processo de isolamento, tanto à escala local - do núcleo urbano, como à microrregional. A hipótese levantada é que dos efeitos positivos e transformadores das ações políticas e institucionais à escala nacional em interação com os potenciais de integração espacial local e regional emergem tendências dissimilares de integração aos processos de mudança da organização social e espacial à escala local, bem como desigualdades em relação às tendências de desenvolvimento local. Para estabelecer a verificação da hipótese, se aplica a teoria, métodos e ferramentas da Sintaxe Espacial e de Análise Espacial para descrever e analisar a configuração espacial do território do município, da região e do núcleo urbano, buscando-se relações dos instrumentos de gestão, infraestrutura regional e de preservação de patrimônio e paisagem cultural, e as configurações espaciais que emergem inscritas em limites territoriais estabelecidos pela aplicação dos instrumentos de planejamento multiescalares. Os resultados da pesquisa indicam que processos top down têm sido insuficientes no que toca potencializar mudanças no desenvolvimento local, para as quais as propriedades morfológicas da rede de circulação regional limitam a difusão espacial de inovações e adesão à reestruturação produtiva por que passa a região. / Research targeting phenomena related to small towns and municipalities’ local development and life quality are becoming widely relevant in the past decades especially when related to urban networks hierarchies at regional scale and addressing productive restructuring issues. Among research problems inscribed in this thematic small towns economic ostracism, loss of population and rural-urban dynamics related to planning regions are recurrent,; most of them focusing on multidimensional and multiscale functional features. However, the spatial dimension of regional segregation and small municipalities’ ostracism phenomena are yet to be `analysis. Therefore, this research objective is to relate regional configurations spatial and morphological variables to social and economic stagnation processes at local scale. The empirical study focuses on Santa Tereza / RS, a municipality inscribed in Serra COREDE, which urban zone is exemplary of The Italian Immigration Region in Brazil. However, institutional agency targeting to improve local development were insufficient to modify the municipality integration into regional productive restructuring processes. In this context, the research problem is addressed from its multiscale spatial dimension. The hypothesis verified is that the positive effects of institutional agency is overwhelmed by spatial segregation patterns of the municipality within the regional urban network, what enhances uneven tendencies of local development and changes in social, economic and spatial organization at local scale. The hypothesis verification methods, based on Space Syntax theory and Spatial Analysis tools provide multiscale configurational descriptions of the segregation phenomena and its interactions with planning strategies. Results indicate that institutional agency is insufficient in changing local development patterns, since morphological variables such as relative accessibility inform segregation tendencies encompassed by the municipality community, limiting the spatial diffusion of innovations.

Greece is a well-known and recommended summer destination since the 1800’s. Greece have has its ups and downs however, travelers have always visited the country. When the economic crisis hit the country a reduction in the numbers of travelers and how those travelers spent their money differently became visable. In social media Greece were presented as an unattractive and unsafe destination to be in. Despite that Greece has developed and went from a stagnation phase to a rejuvenation phase. The Greek economy crisis hit the country hard and Greece did not want to lose its largest source of income – their travelers. In order to not lose their travelers Greece needed help. Theories such as push and pull factors, SWOT-analysis and Butler’s sequence model will be presented and used on Greece as a tourist destination in need of development. In order to approach this problemareas, selected theories and interviews have been the key factor. By including previous research that touches the problem areas, situations can be explained. The previous research will help readers to see on similar ways of handeling crisis problems that have been brought to the surface because of the crisis. Deeper interviews have been done with Apollo, the Greek National Tourism Organisation, students at Södertörns University and also infomers at an event about Greece here in Stockholm. This dissertation will show that Greece was considered being an attractive destination before and also during the year of the crisis, according to its travelers. Travelers did indeed travel to Greece, however, they did not spend much money or time at the destination as earlier. That requiers a re-attraction of travelers and their spendings. In order to re-attract travelers, Greece has to work with its image, marketing and promotion. The figures in this dissertation will show what has to be done, and how to follow some crisis management steps in order to prevent this situations of happening again. As any destination has areas to improve, so has Greece.

A new combustor, referred to as Stagnation Point Reverse Flow (SPRF) combustor has been developed at Georgia Tech to meet increasingly stringent emission regulations. The combustor incorporates a novel design to meet the conflicting requirements of low pollution and high efficiency in both premixed and non-premixed modes. The objective of this thesis is to perform Large Eddy Simulations (LES) on this lab-scale combustor and explain the underlying physics. To achieve this, numerical simulations are performed in both the premixed and non-premixed combustion modes. The velocity field, species field, entrainment characteristics, flame structure, emissions and mixing characteristics are then analyzed. Simulations have been carried out first for a non-reactive case and the flow features in the combustor are analyzed. Next, the simulations have been extended for the premixed reactive case by employing different sub-grid scale combustion chemistry closures - Eddy Break Up (EBU), Artificially Thickened Flame (TF) and Linear Eddy Mixing (LEM) models. Only LEMLES which is an advanced scalar approach is able to accurately predict both the velocity and species field in the combustor. The results from LEM with LES (LEMLES) using a reduced chemical mechanism have been analyzed in the premixed mode. The results showed that mass entrainment occurs along the shear layer in the combustor. The entrained mass carried products into the reactant stream and provided preheating. The product entrainment enhances the reaction rates and stabilizes the flame even at very lean conditions. These products are shown to enter into the flame through local extinction zones present on the flame surface. The flame structure is further analyzed and the combustion mode is found to be primarily in thin reaction zones. The emissions in the combustor are studied using simple global mechanisms for NOx. Computations show extremely low NOx values comparable to the measured emissions. These low emissions are shown to be primarily due to the low temperatures in the combustor. LEMLES computations are also performed with detailed chemistry to capture more accurately the flame structure. The flame in the detailed chemistry case is more sensitive to strain effects and show more extinction zones very near to the injector. LEMLES approach is also used to resolve the combustion mode in the non-premixed case. The studies indicate that mixing of fuel and air close to the injector controls the combustion process. The predictions in the near field are shown to be very sensitive to the inflow conditions. Analysis shows that fuel and air mixing occurs to lean proportions in the combustor before any burning takes place. The flame structure in the non-premixed mode is very similar to the premixed mode. Along with fuel-air mixing, the products also mix with the reactants and provide the preheating effects to stabilize the flame in the downstream region of the combustor.

Estudos que enfocam fenômenos relacionados ao desenvolvimento local e à qualidade de vida em pequenas cidades ou pequenos municípios, ainda quando estes estão inseridos em regiões em processo de reestruturação produtiva e desenvolvimento local, se tornaram relevantes nos últimos anos. Dentre os problemas relacionados a esta temática, a migração das populações e crises do sistema produtivo rural que vem sendo abordados a partir das dimensões econômica, produtiva; das dinâmicas rural-urbano; da qualidade de vida e da governança urbana, são temáticas que servem para descrever e analisar problemas relacionados ao isolamento de pequenas cidades e seus efeitos sobre as redes urbanas regionais, centrados em fatores funcionais multidimensionais e multiescalares. No entanto, a dimensão espacial do fenômeno de isolamento e segregação de pequenas cidades não contemplam especificamente as configurações das redes regionais e os limites territoriais e espaciais impostos à integração regional e ao desenvolvimento local. O objetivo da pesquisa é relacionar as variáveis morfológicas e espaciais das configurações regionais a processos de estagnação social e econômica de pequenos municípios. O estudo de caso empírico é o município de Santa Tereza / RS, inserido na região de planejamento da Serra, recentemente incorporado à Região Metropolitana da Serra Gaúcha, cujo núcleo urbano foi designado pelo IPHAN como exemplar da Paisagem Cultural da Imigração Italiana no Brasil. No entanto, estas ações institucionais multiescalares não modificaram os padrões de desenvolvimento local, nem instigaram a adesão do município às transformações produtivas em curso no contexto regional. O município está, há cinquenta anos, num processo de estagnação econômica, perda de população e alheio às mudanças pelas quais passa a região em que se inscreve. Neste contexto, o problema é discutido a partir da dimensão espacial do processo de isolamento, tanto à escala local - do núcleo urbano, como à microrregional. A hipótese levantada é que dos efeitos positivos e transformadores das ações políticas e institucionais à escala nacional em interação com os potenciais de integração espacial local e regional emergem tendências dissimilares de integração aos processos de mudança da organização social e espacial à escala local, bem como desigualdades em relação às tendências de desenvolvimento local. Para estabelecer a verificação da hipótese, se aplica a teoria, métodos e ferramentas da Sintaxe Espacial e de Análise Espacial para descrever e analisar a configuração espacial do território do município, da região e do núcleo urbano, buscando-se relações dos instrumentos de gestão, infraestrutura regional e de preservação de patrimônio e paisagem cultural, e as configurações espaciais que emergem inscritas em limites territoriais estabelecidos pela aplicação dos instrumentos de planejamento multiescalares. Os resultados da pesquisa indicam que processos top down têm sido insuficientes no que toca potencializar mudanças no desenvolvimento local, para as quais as propriedades morfológicas da rede de circulação regional limitam a difusão espacial de inovações e adesão à reestruturação produtiva por que passa a região. / Research targeting phenomena related to small towns and municipalities’ local development and life quality are becoming widely relevant in the past decades especially when related to urban networks hierarchies at regional scale and addressing productive restructuring issues. Among research problems inscribed in this thematic small towns economic ostracism, loss of population and rural-urban dynamics related to planning regions are recurrent,; most of them focusing on multidimensional and multiscale functional features. However, the spatial dimension of regional segregation and small municipalities’ ostracism phenomena are yet to be `analysis. Therefore, this research objective is to relate regional configurations spatial and morphological variables to social and economic stagnation processes at local scale. The empirical study focuses on Santa Tereza / RS, a municipality inscribed in Serra COREDE, which urban zone is exemplary of The Italian Immigration Region in Brazil. However, institutional agency targeting to improve local development were insufficient to modify the municipality integration into regional productive restructuring processes. In this context, the research problem is addressed from its multiscale spatial dimension. The hypothesis verified is that the positive effects of institutional agency is overwhelmed by spatial segregation patterns of the municipality within the regional urban network, what enhances uneven tendencies of local development and changes in social, economic and spatial organization at local scale. The hypothesis verification methods, based on Space Syntax theory and Spatial Analysis tools provide multiscale configurational descriptions of the segregation phenomena and its interactions with planning strategies. Results indicate that institutional agency is insufficient in changing local development patterns, since morphological variables such as relative accessibility inform segregation tendencies encompassed by the municipality community, limiting the spatial diffusion of innovations.

Estudos que enfocam fenômenos relacionados ao desenvolvimento local e à qualidade de vida em pequenas cidades ou pequenos municípios, ainda quando estes estão inseridos em regiões em processo de reestruturação produtiva e desenvolvimento local, se tornaram relevantes nos últimos anos. Dentre os problemas relacionados a esta temática, a migração das populações e crises do sistema produtivo rural que vem sendo abordados a partir das dimensões econômica, produtiva; das dinâmicas rural-urbano; da qualidade de vida e da governança urbana, são temáticas que servem para descrever e analisar problemas relacionados ao isolamento de pequenas cidades e seus efeitos sobre as redes urbanas regionais, centrados em fatores funcionais multidimensionais e multiescalares. No entanto, a dimensão espacial do fenômeno de isolamento e segregação de pequenas cidades não contemplam especificamente as configurações das redes regionais e os limites territoriais e espaciais impostos à integração regional e ao desenvolvimento local. O objetivo da pesquisa é relacionar as variáveis morfológicas e espaciais das configurações regionais a processos de estagnação social e econômica de pequenos municípios. O estudo de caso empírico é o município de Santa Tereza / RS, inserido na região de planejamento da Serra, recentemente incorporado à Região Metropolitana da Serra Gaúcha, cujo núcleo urbano foi designado pelo IPHAN como exemplar da Paisagem Cultural da Imigração Italiana no Brasil. No entanto, estas ações institucionais multiescalares não modificaram os padrões de desenvolvimento local, nem instigaram a adesão do município às transformações produtivas em curso no contexto regional. O município está, há cinquenta anos, num processo de estagnação econômica, perda de população e alheio às mudanças pelas quais passa a região em que se inscreve. Neste contexto, o problema é discutido a partir da dimensão espacial do processo de isolamento, tanto à escala local - do núcleo urbano, como à microrregional. A hipótese levantada é que dos efeitos positivos e transformadores das ações políticas e institucionais à escala nacional em interação com os potenciais de integração espacial local e regional emergem tendências dissimilares de integração aos processos de mudança da organização social e espacial à escala local, bem como desigualdades em relação às tendências de desenvolvimento local. Para estabelecer a verificação da hipótese, se aplica a teoria, métodos e ferramentas da Sintaxe Espacial e de Análise Espacial para descrever e analisar a configuração espacial do território do município, da região e do núcleo urbano, buscando-se relações dos instrumentos de gestão, infraestrutura regional e de preservação de patrimônio e paisagem cultural, e as configurações espaciais que emergem inscritas em limites territoriais estabelecidos pela aplicação dos instrumentos de planejamento multiescalares. Os resultados da pesquisa indicam que processos top down têm sido insuficientes no que toca potencializar mudanças no desenvolvimento local, para as quais as propriedades morfológicas da rede de circulação regional limitam a difusão espacial de inovações e adesão à reestruturação produtiva por que passa a região. / Research targeting phenomena related to small towns and municipalities’ local development and life quality are becoming widely relevant in the past decades especially when related to urban networks hierarchies at regional scale and addressing productive restructuring issues. Among research problems inscribed in this thematic small towns economic ostracism, loss of population and rural-urban dynamics related to planning regions are recurrent,; most of them focusing on multidimensional and multiscale functional features. However, the spatial dimension of regional segregation and small municipalities’ ostracism phenomena are yet to be `analysis. Therefore, this research objective is to relate regional configurations spatial and morphological variables to social and economic stagnation processes at local scale. The empirical study focuses on Santa Tereza / RS, a municipality inscribed in Serra COREDE, which urban zone is exemplary of The Italian Immigration Region in Brazil. However, institutional agency targeting to improve local development were insufficient to modify the municipality integration into regional productive restructuring processes. In this context, the research problem is addressed from its multiscale spatial dimension. The hypothesis verified is that the positive effects of institutional agency is overwhelmed by spatial segregation patterns of the municipality within the regional urban network, what enhances uneven tendencies of local development and changes in social, economic and spatial organization at local scale. The hypothesis verification methods, based on Space Syntax theory and Spatial Analysis tools provide multiscale configurational descriptions of the segregation phenomena and its interactions with planning strategies. Results indicate that institutional agency is insufficient in changing local development patterns, since morphological variables such as relative accessibility inform segregation tendencies encompassed by the municipality community, limiting the spatial diffusion of innovations.

This thesis is devoted to long-term stagnation of the Japanese economy and potential solutions addressing such issue. The aim of this thesis is to propose a suitable solution to Japan's long-term stagnation. Firstly, the theoretical as well as practical basis of current Japan's stagnation is described. Economic theory and basic economic principles are explained within the theoretical background in order to apply such knowledge to the real economy correctly. Then, Japan's economic development from the second half of the 20th century till present is outlined within the practical background with an emphasis on "Lost decade" and persisting stagnation to better understand the way the Japanese economy functions. Secondly, the causes of Japan's "Lost decade" and persisting stagnation are presented. The theoretical basis of the causes of long-term stagnation is outlined with an emphasis on economic policy as a key instrument that affects the real economy. Then, the causes of Japan's long-term stagnation are deeply analyzed including a confrontation of selected causes by the author. Lastly, potential solutions addressing the issue of long-term economic stagnation are discussed. Existing solutions that aim to end Japan's stagnation are described and assessed. The main contribution of the author lies in proposing a solution to Japan's long-term economic stagnation from the author's perspective including specific measures to restore economic growth.

La stagnation est un phénomène fréquent dans le domaine de la natation, bien qu’inexpliqué et incompris, pour lequel peu de solutions sont proposées. Malgré quelques recherches sur ce phénomène, notamment au baseball, la littérature sur le sujet demeure incomplète et ne permet pas de bien cerner le problème de la stagnation. Ainsi, cette étude a pour but premier d’identifier et de comprendre les causes possibles de la stagnation, les changements émotionnels, physiques et sociaux engendrés par un tel phénomène et les stratégies utilisées par les athlètes pour gérer la stagnation. Le deuxième objectif de cette étude est de jeter un regard sur l’impact de l’optimisme sur la résolution de la stagnation. Pour ce faire, des entrevues semi-structurées ont été menées auprès de onze nageurs ayant compétitionné au niveau national canadien. Les nageurs étaient divisés en trois groupes: les nageurs ayant résolu leur stagnation et qui continuent de nager, les nageurs ayant cessé la compétition de natation suite à une stagnation non résolue et ceux qui nagent encore malgré une stagnation non résolue. Les candidats sélectionnés ont complété deux questionnaires sur l’optimisme, le LOT-R et l’ASQ. L’analyse des résultats, réalisée grâce à la théorisation ancrée, a permis de déterminer un ensemble d’émotions vécues par les athlètes et d’identifier des stratégies afin de résoudre la stagnation. Les résultats de cette étude indiquent qu’une balance entre l’optimisme et le pessimisme, une motivation intrinsèque ainsi qu’une auto-détermination chez l'athlète sont des éléments importants afin de surmonter une stagnation. / Even if unexplained and misunderstood, a slump is a frequent phenomenon among high level swimmers for which few solutions are proposed. Despite some previous research especially in the sport of baseball, the literature on this topic is fairly incomplete and does not provide a complete understanding of the problem. Therefore, the primary goal of this study is to get a better understanding of the possible causes of a slump and the emotional, mental, physical and social changes generated by this phenomenon and the strategies used by swimmers in order to break through their slumps. The second goal of this study is to examine the impact of optimism on the resolution of a slump. To reach these goals, semi-structured interviews were held with eleven swimmers who competed at the national level in Canada. Swimmers were divided into three groups: swimmers who resolved their slumps and are still swimming, swimmers who stopped competitive swimming because of an unresolved slump and swimmers who are still swimming even though they are still enduring a slump. Subjects selected were also asked to complete two optimism questionnaires (LOT-R and ASQ). Data analysis, using the grounded theory, identified an emotional patterns experienced by swimmers and certain strategies used by swimmers to resolve their slump. Finally, the results of this study suggest that a balance between optimism and pessimism, an intrinsic motivation and a perception of auto-determination are important elements when trying to overcome a slump.