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The linearized Einstein equation describing graviton propagation through a chiral medium appears to be helicity dependent. We analyze features of the corresponding spectrum in a collision-less regime above a flat background. In the long wave-length limit, circularly polarized metric perturbations travel with a helicity dependent group velocity that can turn negative giving rise to a new type of an anomalous dispersion. We further show that this chiral anomalous dispersion is a general feature of polarized modes propagating through chiral plasmas extending our result to the electromagnetic sector.

Computations and experiments were run to study adiabatic effectiveness and thermal field contours for a simulated turbine blade leading edge. The RKE and SST k-[omega] turbulence models were used for the computational simulations. Predictions of RKE model for laterally averaged adiabatic effectiveness matched the experimental values. The computational simulations showed different flowfield for the coolant exiting the stagnation line row of holes. Both the experiments and SST k-[omega] simulations predicted coolant separation at the stagnation plane. Also, the downstream spreading of the coolant exiting the stagnation row of exit holes was better predicted by the SST k-[omega] model. At the stagnation plane, experimental thermal field measurements showed greater diffusion of the coolant into the mainstream than predicted by both turbulence models. Reasons for increased diffusion were examined. Thermal field comparison downstream of the offstagnation row of exit holes showed that the computational simulations and the experiments had the same general shape for the offstagnation coolant jet. But the computational simulations predicted greater diffusion of coolant in the direction normal to the surface than seen in the experiments. / text

Dentro da abordagem dinâmica do clima, o presente trabalho visou a estudar a configuração espaço-temporal do campo térmico da cidade de São Carlos-SP, dentro de suas variações diurnas e das condições impostas pelos diferentes tipos de tempo, com o intuito de caracterizá-lo quanto à sua intensidade e identificar a formação de ilhas urbanas de calor no período de inverno. Para tanto foram utilizados dados climáticos registrados por três estações automáticas localizadas em pontos distintos da malha urbana, imagens do satélite GOES e cartas de pressão atmosféricas reduzidas ao nível do mar. De acordo com os resultados obtidos, a ilha de calor urbana é mais pronunciada na fase de domínio da massa Polar Atlântica, sendo que as maiores diferenças térmicas foram observadas durante o período diurno. Sob as condições impostas pela massa Polar Atlântica as diferenças observadas entre os campos térmicos da região mais próxima do centro urbano de São Carlos e as duas regiões mais afastadas ficaram entre 2,0 e 3,0°C. / On the dynamical approach of climate, the present work aimed the study the time-space configuration of the thermal filed of the city of São Carlos-SP, within the diurnal variations and the conditions imposed by the different weather types, in order to characterize its intensity and identify the formation of urban heat islands during winter. Thus climatic data registered by three automatic stations located in distinct points of the urban network, GOES satellite images and atmospheric pressure letters at sea level were used. According to the obtained results, the urban heat island is more pronounced in the activity of Polar Atlantic air mass, with the biggest thermal differences being observed during the diurnal period. Under the conditions imposed by the Polar Atlantic mass the observed differences between the thermal fields of the nearest downtown region of São Carlos and the two distant regions were between 2.0 and 3.0 ºC.

The AdS/CFT correspondence and its extensions to more general gauge/gravity dualities have provided a powerful framework for the study of strongly coupled gauge theories. This thesis explores properties of a large class of thermal strongly coupled gauge theories using the gravity dual. In order to bring the holographic framework closer to Quantum Chromodynamics (QCD), we study theories with matter in the fundamental representation. In particular, we focus on the holographic dual of SU(Nc) supersymmetric Yang-Mills theory coupled to Nf<<Nc flavours of fundamental matter at finite temperature, which is realised as Nf Dq-brane probes in the near horizon (black hole) geometry of Nc black Dp-branes. We explore many aspects of these Dp/Dq brane systems, often focussing on the D3/D7 brane system which is dual to a four dimensional gauge theory. We study the thermodynamics of the Dq-brane probes in the black hole geometry. At low temperature, the branes sit outside the black hole and the meson spectrum is discrete and possesses a mass gap. As the temperature increases, the branes approach a critical solution. Eventually, they fall into the horizon and a phase transition occurs. At large Nc and large 't Hooft coupling, we show that this phase transition is always first order. We calculate the free energy, entropy and energy densities, as well as the speed of sound in these systems. We compute the meson spectrum for brane embeddings outside the horizon and find that tachyonic modes appear where this phase is expected to be unstable from thermodynamic considerations. We study the system at non-zero baryon density nb and find that there is a line of phase transitions for small nb, terminating at a critical point with finite nb. We demonstrate that, to leading order in Nf/Nc, the viscosity to entropy density ratio in these theories saturates the conjectured universal bound. Finally, we compute spectral functions and diffusion constants for fundamental matter in the high temperature phase of the D3/D7 theory.

The AdS/CFT correspondence and its extensions to more general gauge/gravity dualities have provided a powerful framework for the study of strongly coupled gauge theories. This thesis explores properties of a large class of thermal strongly coupled gauge theories using the gravity dual. In order to bring the holographic framework closer to Quantum Chromodynamics (QCD), we study theories with matter in the fundamental representation. In particular, we focus on the holographic dual of SU(Nc) supersymmetric Yang-Mills theory coupled to Nf<<Nc flavours of fundamental matter at finite temperature, which is realised as Nf Dq-brane probes in the near horizon (black hole) geometry of Nc black Dp-branes. We explore many aspects of these Dp/Dq brane systems, often focussing on the D3/D7 brane system which is dual to a four dimensional gauge theory. We study the thermodynamics of the Dq-brane probes in the black hole geometry. At low temperature, the branes sit outside the black hole and the meson spectrum is discrete and possesses a mass gap. As the temperature increases, the branes approach a critical solution. Eventually, they fall into the horizon and a phase transition occurs. At large Nc and large 't Hooft coupling, we show that this phase transition is always first order. We calculate the free energy, entropy and energy densities, as well as the speed of sound in these systems. We compute the meson spectrum for brane embeddings outside the horizon and find that tachyonic modes appear where this phase is expected to be unstable from thermodynamic considerations. We study the system at non-zero baryon density nb and find that there is a line of phase transitions for small nb, terminating at a critical point with finite nb. We demonstrate that, to leading order in Nf/Nc, the viscosity to entropy density ratio in these theories saturates the conjectured universal bound. Finally, we compute spectral functions and diffusion constants for fundamental matter in the high temperature phase of the D3/D7 theory.

Dentro da abordagem dinâmica do clima, o presente trabalho visou a estudar a configuração espaço-temporal do campo térmico da cidade de São Carlos-SP, dentro de suas variações diurnas e das condições impostas pelos diferentes tipos de tempo, com o intuito de caracterizá-lo quanto à sua intensidade e identificar a formação de ilhas urbanas de calor no período de inverno. Para tanto foram utilizados dados climáticos registrados por três estações automáticas localizadas em pontos distintos da malha urbana, imagens do satélite GOES e cartas de pressão atmosféricas reduzidas ao nível do mar. De acordo com os resultados obtidos, a ilha de calor urbana é mais pronunciada na fase de domínio da massa Polar Atlântica, sendo que as maiores diferenças térmicas foram observadas durante o período diurno. Sob as condições impostas pela massa Polar Atlântica as diferenças observadas entre os campos térmicos da região mais próxima do centro urbano de São Carlos e as duas regiões mais afastadas ficaram entre 2,0 e 3,0°C. / On the dynamical approach of climate, the present work aimed the study the time-space configuration of the thermal filed of the city of São Carlos-SP, within the diurnal variations and the conditions imposed by the different weather types, in order to characterize its intensity and identify the formation of urban heat islands during winter. Thus climatic data registered by three automatic stations located in distinct points of the urban network, GOES satellite images and atmospheric pressure letters at sea level were used. According to the obtained results, the urban heat island is more pronounced in the activity of Polar Atlantic air mass, with the biggest thermal differences being observed during the diurnal period. Under the conditions imposed by the Polar Atlantic mass the observed differences between the thermal fields of the nearest downtown region of São Carlos and the two distant regions were between 2.0 and 3.0 ºC.

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / O objetivo deste trabalho se constitui em caracterizar o clima produzido pela cidade de Fortaleza/CE, sob o nÃvel termodinÃmico do S.C.U. (MONTEIRO, 1976) numa dimensÃo linear tendo como referÃncia doze pontos experimentais representativos da realidade urbana. Para isso, houve a realizaÃÃo de dois experimentos de regimes sazonais diferenciados com registros horÃrios e simultÃneos em perfis de 24 horas (7 Ãs 6 horas). O primeiro experimento realizado no outono austral, perÃodo da quadra chuvosa na regiÃo, nos dias 04 e 05/05/2007 e o segundo na primavera, perÃodo da quadra seca, nos dias 09 e 10/11/2007. Os resultados encontrados seguem o ritmo da habitualidade climÃtica dos episÃdios sazonais analisados, sendo os sistemas de circulaÃÃo atmosfÃrica fatores determinantes no comportamento tÃrmico da cidade. A pesquisa identificou que as ilhas de calor em Fortaleza podem ultrapassar o valor de 5ÂC e ocorrem com maior freqÃÃncia e intensidade no perÃodo diurno entre as 7 e 15 horas. As espacializaÃÃes das ilhas de calor se concentraram nos setores sudoeste, oeste, noroeste e porÃÃo central da cidade. / The objective of the work is constituted in characterizing the climate produced by the city of Fortaleza/CE, under the level thermodynamic of the S.C.U. (MONTEIRO, 1976) in a linear dimension taking as a reference twelve experimental representative points of the urbane reality. For that there was the realization of two experiments in seasonal regimes differentiated with registers time-tables and simultaneous in profiles of 24 hours (7 at 6 hours).The first thing carried out in the southern autumn, period of the rainy block in the region, in the days 04 and 05/05/2007 and according to in the spring, period of the dry block, in the days 09 and 11/10/2007.The considered results follow the rhythm of the climatic of the seasonal analysed episodes, being the systems of atmospheric circulation determinative factors in the thermal behaviour of the city.The inquiry identified that the islands of heat in Fortress can exceed the value of 5ÂC and take place with bigger frequency and intensity in the daytime period between 7 and 15 hours. The specializations of the islands of heat concentrated on the sectors south-west, west, northwest and central portion of the city.

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / O objetivo deste trabalho se constitui em caracterizar o clima produzido pela cidade de Fortaleza/CE, sob o nÃvel termodinÃmico do S.C.U. (MONTEIRO, 1976) numa dimensÃo linear tendo como referÃncia doze pontos experimentais representativos da realidade urbana. Para isso, houve a realizaÃÃo de dois experimentos de regimes sazonais diferenciados com registros horÃrios e simultÃneos em perfis de 24 horas (7 Ãs 6 horas). O primeiro experimento realizado no outono austral, perÃodo da quadra chuvosa na regiÃo, nos dias 04 e 05/05/2007 e o segundo na primavera, perÃodo da quadra seca, nos dias 09 e 10/11/2007. Os resultados encontrados seguem o ritmo da habitualidade climÃtica dos episÃdios sazonais analisados, sendo os sistemas de circulaÃÃo atmosfÃrica fatores determinantes no comportamento tÃrmico da cidade. A pesquisa identificou que as ilhas de calor em Fortaleza podem ultrapassar o valor de 5ÂC e ocorrem com maior freqÃÃncia e intensidade no perÃodo diurno entre as 7 e 15 horas. As espacializaÃÃes das ilhas de calor se concentraram nos setores sudoeste, oeste, noroeste e porÃÃo central da cidade. / The objective of the work is constituted in characterizing the climate produced by the city of Fortaleza/CE, under the level thermodynamic of the S.C.U. (MONTEIRO, 1976) in a linear dimension taking as a reference twelve experimental representative points of the urbane reality. For that there was the realization of two experiments in seasonal regimes differentiated with registers time-tables and simultaneous in profiles of 24 hours (7 at 6 hours).The first thing carried out in the southern autumn, period of the rainy block in the region, in the days 04 and 05/05/2007 and according to in the spring, period of the dry block, in the days 09 and 11/10/2007.The considered results follow the rhythm of the climatic of the seasonal analysed episodes, being the systems of atmospheric circulation determinative factors in the thermal behaviour of the city.The inquiry identified that the islands of heat in Fortress can exceed the value of 5ÂC and take place with bigger frequency and intensity in the daytime period between 7 and 15 hours. The specializations of the islands of heat concentrated on the sectors south-west, west, northwest and central portion of the city.

This thesis is dealing with thermal fields and the possibilities of their solution by a finite element method. Thereinafter thesis describe assembling a 3D model of induction machine with known parameters, and solving thermal field of the model by Ansys Workbench program and verification of these results by practical measuring on real machine.