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Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro / A formulação explícita matricial desenvolvida nesta tese de doutorado foi proposta visando ser uma alternativa na solução de Problemas Inversos de estimativa de propriedades radiativas em meios participantes homogêneos unidimensionais usando a Equação de Transferência Radiativa para modelar a interação da radiação com o meio participante. A equação de transporte é formulada em forma matricial e o domínio angular é discretizado usando conceitos do método de ordenadas discretas e a expansão da função de fase do espalhamento anisotrópico em uma série de polinômios de Legendre. A formulação proposta consiste em uma formulação explícita para o problema inverso. Um arranjo apropriado das condições de contorno prescritas (fluxos incidentes) e dos fluxos emergentes nos contornos de uma placa permitem o cálculo direto do operador de transmissão, do operador albedo e do operador de colisão. A partir do operador de colisão calculado são obtidos os valores estimados dos coeficientes de extinção total e de espalhamento. São apresentadas as formulações para problemas em regime estacionário e em regime transiente, bem como os resultados para alguns casos-teste. / The explicit matrix formulation developed in the present thesis has been proposed as an alternative for the solution of Inverse Problems for radiative properties estimation in one-dimensional homogeneous participating media using Radiative transfer equation for the modeling of the radiation interaction with the participating medium. This transport equation is formulated in a matrix form and the angular domain is discretized using concepts of the discrete ordinates methods and the expansion of the function of phase function of anisotropic scattering in a series of Legendre polynomial. The formulation proposed consists on an explicit formulation for the inverse problem. An adequate assembly of the prescribed boundary conditions (incidents flux) and of the emerging flux at the boundaries of the slab allows the direct computation of the transmission, albedo and collision operators. From the computed collision operator estimated values for total extinction and scattering coefficients are obtained. The formulations for steady state and transient situations are presented, as well as test case results.

Nesta tese é proposta uma implementação para a solução do problema inverso com as estimativas das propriedades radiativas (o albedo de espalhamento simples, a espessura ótica do meio e as reflectividades difusas) a partir dos valores das intensidades de radiação que deixam o meio participante utilizando uma abordagem híbrida de sistemas neuro-fuzzy (SNF), o qual combina a utilização de sistemas de inferência fuzzy com as redes neurais artificiais. Busca-se com a utilização desse sistema híbrido integrar a habilidade dos sistemas fuzzy no tratamento de informações inexatas, imprecisas, e vagas, e a capacidade das redes neurais artificiais de tratar o aprendizado por experiência e a generalização do conhecimento. É proposta também uma metodologia de máquinas de comitês neuro-fuzzy na solução deste problema inverso em transferência radiativa. Foi observado paralelamente que a solução dos sistemas neuro-fuzzy e dos sistemas híbridos de máquinas de comitê neuro-fuzzy, apresentam baixa qualidade nos resultados quando são utilizados os dados experimentais com os menores coeficientes de sensibilidade para os parâmetros que serão estimados. Por outro lado, quando são utilizados dados com maior sensibilidade, são obtidos melhores resultados. Esta abordagem procura evitar a possibilidade da não convergência desses métodos. / In this thesis is proposed an implementation for solving the inverse problem with the estimates of radiative properties (the single scattering albedo, the optical thickness of the media and the diffuse reflectivities) by the values of the intensities of radiation that leaves the participant medium using a hybrid approach of neuro-fuzzy systems, which combines the use of fuzzy inference systems with artificial neural networks. The use of this hybrid system try to include the ability of fuzzy systems in the treatment of inaccurate, imprecise, and vague data, and the ability of artificial neural networks to deal with learning from experience and widespread knowledge. Also is proposed a methodology for machines committees in neuro-fuzzy solution of this inverse problem in radiative transfer. It was observed in parallel that the solution of neuro-fuzzy systems and hybrid systems neuro-fuzzy committee machines, have a poor quality results when using the experimental data with the lowest sensitivity coefficients for the parameters that will be estimated. Moreover, when data are used with greater sensitivity, better results are obtained. This approach seeks to avoid the possibility of non-convergence in such methods.

Este trabalho fundamenta-se no conceito de máquina de comitê de redes neurais artificiais e tem por objetivo resolver o problema inverso de transferência radiativa em um meio unidimensional, homogêneo, absorvedor e espalhador isotrópico. A máquina de comitê de redes neurais artificiais agrega e combina o conhecimento adquirido por um certo número de especialistas aqui representados, individualmente, por cada uma das redes neurais artificiais (RNA) que compõem a máquina de comitê de redes neurais artificiais. O objetivo é atingir um resultado final melhor do que o obtido por qualquer rede neural artificial separadamente, selecionando-se apenas àquelas redes neurais artificiais que apresentam os melhores resultados na fase de generalização descartando-se as demais, o que foi feito neste trabalho. Aqui são utilizados dois modelos estáticos de máquinas de comitê, usando a média aritmética de conjunto, que se diferenciam entre si apenas na composição do combinador de saída de cada máquina de comitê. São obtidas, usando-se máquinas de comitê de redes neurais artificiais, estimativas para os parâmetros de transferência radiativa, isto é, a espessura óptica do meio, o albedo de espalhamento simples e as refletividades difusas. Finalmente, os resultados obtidos com ambos os modelos de máquina de comitê são comparados entre si e com aqueles encontrados usando-se apenas redes neurais artificiais do tipo perceptrons de múltiplas camadas (MLP), isoladamente. Aqui essas redes neurais artificiais são denominadas redes neurais especialistas, mostrando que a técnica empregada traz melhorias de desempenho e resultados a um custo computacional relativamente baixo. / This work is based on the concept of neural networks committee machine and has the objective to solve the inverse radiative transfer problem in one-dimensional, homogeneous, absorbing and isotropic scattering media. The artificial neural networks committee machine adds and combines the knowledge acquired by an exact number of specialists which are represented, individually, by each one of the artificial neural networks (ANN) that composes the artificial neural network committee machine. The aim is to reach a final result better than the one obtained by any of the artificial neural network separately, selecting only those artificial neural networks that presents the best results during the generalization phase and discarding the others, what was done in this present work. Here are used two static models of committee machines, using the ensemble arithmetic average, that differ between themselves only by the composition of the output combinator by each one of the committee machine. Are obtained, using artificial neural networks committee machines, estimates for the radiative transfer parameters, that is, medium optical thickness, single scattering albedo and diffuse reflectivities. Finally, the results obtained with both models of committee machine are compared between themselves and with those found using artificial neural networks type multi-layer perceptrons (MLP), isolated. Here that artificial neural networks are named as specialists neural networks, showing that the technique employed brings performance and results improvements with relatively low computational cost.

Esta tese apresenta um estudo sobre modelagem computacional onde são aplicadas meta-heurísticas de otimização na solução de problemas inversos de transferência radiativa em meios unidimensionais com albedo dependente da variável óptica, e meios unidimensionais de duas camadas onde o problema inverso é tratado como um problema de otimização. O trabalho aplica uma meta-heurística baseada em comportamentos da natureza conhecida como algoritmo dos vagalumes. Inicialmente, foram feitos estudos comparativos de desempenho com dois outros algoritmos estocásticos clássicos. Os resultados encontrados indicaram que a escolha do algoritmo dos vagalumes era apropriada. Em seguida, foram propostas outras estratégias que foram inseridas no algoritmo dos vagalumes canônico. Foi proposto um caso onde se testou e investigou todas as potenciais estratégias. As que apresentaram os melhores resultados foram, então, testadas em mais dois casos distintos. Todos os três casos testados foram em um ambiente de uma camada, com albedo de espalhamento dependente da posição espacial. As estratégias que apresentaram os resultados mais competitivos foram testadas em um meio de duas camadas. Para este novo cenário foram propostos cinco novos casos de testes. Os resultados obtidos, pelas novas variantes do algoritmo dos vagalumes, foram criticamente analisados. / This thesis presents a study on computational modeling where optimization metaheuristics are applied to the solution of inverse radiative transfer problems in heterogeneous media: in one-layer media with space-dependent single scattering albedo, and two-layer media, where the inverse problem is formulated as an optimization problem. It is applied a metaheuristic based on the natural behavior of fireflies, known as the firefly algorithm. Initially, comparative studies of performance were made with two other classic stochastic algorithms. The results indicated that the choice of the firefly algorithm was appropriate. Then, it was proposed other strategies that have been inserted into the original firefly algorithm. A first case was proposed where all the strategies were investigated and tested. The strategies with the best results were investigated in other two different cases. All the three proposed cases involved one-layer media with space-dependent scattering albedo. The strategies have been tested and evaluated, and those which presented the best competitive results were then implemented for radiative problems in two-layer media. For this new scenario five test cases were investigated, and the results obtained with the new strategies developed in this work were critically analyzed.

Cette thèse porte sur une méthodologie d’estimation des capacités d’un futur instrument spatioporté. Le cas d’étude est l’instrument Flexible Combined Imager (FCI) à bord du futur satellite Meteosat Troisième Génération Imageur (MTG-I), et plus particulièrement ses capacités à détecter des variations de quantité d’aérosols désertiques dans l’atmosphère. Une meilleure connaissance de ces aérosols fait partie des besoins régulièrement exprimés pour l’étude du climat, la prévision météorologique ou l’estimation de la ressource solaire dans des zones arides comme le Sahara. Ce type d’aérosols est abondant dans l’atmosphère. Leurs propriétés physico-chimique les rendent distinguables des autre types d’aérosols comme ceux résultant de la pollution d’origine anthropique, d’autant qu’ils sont émis dans des zones protégées des contaminations par ces autres types. Ils représentent donc un cas d’étude simple pour valider la méthodologie développée dans cette thèse.La méthodologie consiste à réaliser un simulateur de vue du sol par l’instrument, à effectuer de très nombreuses simulations des luminances mesurées par l’instrument sous diverses conditions atmosphériques et de l’albédo du sol, à analyser les résultats de manière à quantifier l’influence de chaque variable dans la variation de la luminance, puis à conclure quant aux capacités de détection grâce un critère de détectabilité prenant en compte les caractéristiques de l’instrument.Le simulateur développé a été validé par confrontation avec des mesures réelles de l’instrument SEVIRI à bord du satellite Meteosat Second Generation. L’innovation principale réside dans l’usage de l’approche d’analyse de sensibilité globale (GSA). Cette dernière quantifie l’influence de chaque variable séparément ainsi que les termes croisés. Elle exploite des fonctions de répartition statistique des variables extraites d’observations, et permet par conséquent d’obtenir une analyse de sensibilité réaliste. La GSA produit aussi des fonctionnelles modélisant l’influence d’une ou plusieurs variables sur la variabilité du signal observé et utilisables pour différentes applications dans la télédétection. / This thesis deals with a methodology to assess the capabilities of future spaceborne instruments. The case study is the Flexible Combined Imager (FCI) of the future Meteosat Third Generation Imaging mission (MTG - I), and in particular its ability to detect variations in load of desert aerosols in a realistically variable atmosphere. A better understanding of the behavior of these aerosols is part of regularly expressed needs for the study of the climate, weather forecast or assessment of the solar resource in arid areas such as the Sahara. This type of aerosols is abundant in the atmosphere. Their physical and chemical properties make them distinguishable from other types of aerosols such as those resulting from anthropogenic pollution, especially as they are emitted in areas protected from contamination by these other types. They therefore represent a simple case study to validate the methodology developed in this thesis.The methodology is to provide a simulator of the view of the instrument to perform a large number of simulations of the radiance measured under different atmospheric conditions and ground albedo, to analyze the results in order to quantify the influence of each variable in the variation of radiance, and then conclude on the capabilities of detection through a test of detectability taking into account the characteristics of the instrument.The developed simulator was validated by comparison against actual measurements of the SEVIRI instruments onboard Meteosat Second Generation satellites. The main innovation lies in the use of the global sensitivity analysis approach (GSA). The latter quantifies the influence of each variable separately as well as their crossed terms. Cumulative distribution functions were computed from actual observations and allow a realistic sensitivity analysis of the instrument. The GSA is also used to compute functional representation of the influence of one or more variables on the variability of the observed signal. The usefulness of such representations is discussed for various applications in remote sensing.

Dans une première partie, nous mesurons l'affinité de l'interaction entre [Ru(pby)2dppz]2+ et l'ADN en utilisant la luminescence induite lors de la complexation. Nous étudions l'évolution de l'affinité lorsque la force ionique de la solution augmente. Dans une deuxième partie, nous modifions les extrémités d'un double brin d'ADN en y greffant des fluorophores. De la mesure de transfert d'énergie non-radiative entre ces fluorophores, nous étudions l'évolution de la longueur du complexe. Nous effectuons un dosage d'un double brin de 15 paires de bases d'ADN par le complexe ruthéné. Nous nous servons de la luminescence induite par l'intercalation du groupement dppz. Cependant, l'incrément de luminescence par groupement intercalé n'est pas connu, et nous ne pouvons pas le mesurer en saturant le brin d'ADN. Nous utilisons alors une technique mise au point par Nishida [Method for Measuring the Binding of Small Molecules to Proteins from Binding-Induced Alterations of Physical-Chemical Properties], dans laquelle deux titrations de deux solutions d'ADN de deux concentrations différentes sont effectuées. En utilisant le fait que, lorsque deux solutions d'ADN complexé par le composé ruthéné, possèdent la même luminescence par paire de base , le taux de complexation de ces deux solutions doit être le même, nous pouvons alors déterminer, sans hypothèse supplémentaire, le taux de complexation de l'ADN. De l'évolution de ce taux en fonction avec la concentration de ligand, nous déduisons son affinité pour l'ADN. Nous étudions maintenant le changement de longueur d'un double brin d'ADN de 15 paires de bases, modifié à ses deux extrémités par deux fluorophores : Alexa488 et Alexa568. Lorsque Alexa 488 est porté dans un état excité, il peut se désexciter en transférant de l'énergie de manière non-radiative à Alexa568, qui se désexcite alors en émettant des photons de plus faibles énergie que ceux émis par Alexa488. L'efficacité de ce transfert d'énergie peut être quantifié à partir de la mesure des intensités émises à basse et haute énergie. Elle dépend a priori de l'efficacité couplage (et en conséquence de la distance) entre les deux fluorophores. Nous effectuons des mesures de temps de vie des états excités de chacun des fluorophores. Nous avons observé que l'addition de ligand a pour conséquence une forte inhibition quenching des fluorophores. De l'analyse de l'évolution du temps de vie du fluorophore donneur d'une part et de celui du fluorophore accepteur d'autre part, nous déduisons l'évolution de l'efficacité du transfert d'énergie en fonction de la concentration de ligand. Nous confrontons les résultats obtenus par chacune de ces analyses, et en déduisons finalement, en nous servant de l'analyse de l'équilibre effectuée dans la première partie, l'évolution de la longueur de la chaîne en fonction du taux de complexation / This Ph.D thesis is mainly divided in to 2 parts. The first part is luminescence study, we are interested in the affinity constant (Ka) change under different salinity environments when the complexation of [Ru(bpy)2dppz]2+-DNA arrive equilibrium. In the second part, we focus our attention on the kinetic study by fluorescence which comes from the fluorophore. The distance change between 2 fluorophores is explored when [Ru(bpy)2dppz]2+ intercalates into DNA, which lead to the variation of DNA conformation. Any changes in DNA conformation will be reflected by the efficiency change of fluorescence resonance energy transfer (FRET). Quantitative analysis on the Ru(bpy)2dppz]2+-DNA interaction will be built in the second part. In the first part, the interaction of [Ru(bpy)2dppz]2+ with DNA is studied in a wide range of DNA / [Ru(bpy)2dppz]2+ ratios by using the luminescence signal which comes from complex. The affinity constant (Ka) is explored under different chloride sodium concentration (NaCl=[0, 100 mM]), when the complexation reaches equilibrium. Nishida method is employed to compute the value of Ka without any hypothesis. The value of affinity constant is at the level scale of 106 M-1 which is basically identical to the other researcher’s results. Ka decreased with increasing the concentration of NaCl as we expected. Quantitative analysis on the Ru(bpy)2dppz]2+-DNA interaction will be done in the second part. DNA was modified by different fluorophores at its extremities, 5’ end and 3’ end were labeled with alexa488 (seen as donor) and alexa568 (seen as acceptor), respectively. Our goal is to study the efficiency change of FRET and the change of distance between 2 fluorophores with fluorescence technique when one Ruthenium molecule intercalate in to DAN base pair. Two methods will be employed to achieve our idea. One is that the efficiency of FRET can be computed from the donor emission (alexa488), the other is the efficiency of FRET can be calculated from the acceptor emission (acceptor), the efficiency of FRET is highly dependent on the distance of 2 fluorophores (), any changes in distance will cause the efficiency change. The FRET efficiency decreased when the [Ru(bpy)2dppz]2+ intercalated into DNA structure, which also meant that the distance between 2 fluorohore increased.

Malgré l’existence de modèles précis, notre connaissance des structures à petite échelle des galaxies est toujours limitée par le manque de preuves observationnelles. Les progrès instrumentaux ont permis d’atteindre une haute résolution angulaire à l’aide des nouvelles générations de télescopes, mais celle-ci est restreinte à un faible nombre de cibles extragalactiques à causes des besoins de l’Optique Adaptative (OA). En effet, afin de permettre une mesure efficace du front d’onde, l’OA requiert une source brillante et ponctuelle proche de la cible scientifique, typiquement en dessous de 30 . La partie principale de cette thèse porte sur l’analyse de la dizaine de parsecs centrale des Galaxies à Noyaux Actifs (NAG) à l’aide de différentes techniques observationnelles et numériques. Nous avons dans ce contexte développé un code de transfert radiatif nous permettant d’analyser les données polarimétriques. La seconde partie de ce travail est dédiée à l’analyse d’images en proche infrarouges de galaxies à flambée d’étoiles afin de contraindre les paramètres décrivant les super amas stellaires, jeunes cocons de poussière très massifs abritant une formation d’étoiles très soutenue, à l’aide de données obtenues avec l’instrument CANARY, démonstrateur de nouvelles technologies d’OA. / Despite having strong theoretical models, the current limitation in our understanding of the small-scale structures of galaxies is linked to the lack of observational evidences. Many powerful telescopes and instruments have been developed in the last decades, however one of these strongest tools, namely Adaptive Optics (AO), can only be used on a very limited number of targets. Indeed, for AO to be efficient, a bright star is required close to the scientific target, typically under 30 . This is mandatory for the AO systems to be able to measure the atmospheric turbulence and this condition is rarely satisfied for extended extragalactic targets such as galaxies. The main part of this thesis work consisted in going deeper in the analysis of the inner tens of parsecs of Active Nuclei (AGN) by combining different techniques to obtain and to interpret new data. In this context, we developed a new radiative transfer code to analyse the polarimetric data. A second part of my work was dedicated to a high angular resolution study of Super Star Clusters (SSC) in a new system, thanks to data obtained with the AO demonstrator CANARY instrument.

Les centrales solaires à concentration industrielles consomment 4 m3/MWh d’eau pour le refroidissement de leur cycle thermodynamique. En environnement aride, cela est susceptible d'induire des conflits d’usages sur une ressource encore plus fondamentale que l’électricité, l'eau. Ce constat met en évidence la nécessité de concevoir des solutions alternatives de refroidissement sèches mais tout aussi efficaces. Le champ solaire d’une centrale CSP représente 50% de son coût d’investissement pour n’être utilisé que de jour pour la production de chaleur nécessaire au cycle thermodynamique. L'approche du sujet de thèse consiste à utiliser cette surface considérable comme macro-échangeur de chaleur avec son environnement via un transfert thermique couplé avec l'air ambiant (convectif) et avec l'espace extra-atmosphérique à 3K (radiatif). Après avoir démontré la pertinence des matériaux du champ solaire pour une telle application, le travail de thèse a montré expérimentalement qu'au-delà d'extraire les chaleurs fatales du cycle thermodynamique, il pouvait aussi produire du froid par transfert radiatif nocturne. Une solution alternative innovante pour le refroidissement des centrales solaires CSP offrant deux nouvelles fonctionnalités à leur champ solaire déjà existant au bénéfice de son amortissement. / Industrial concentrated solar power plants consume 4 m3/MWh of water to cool down their thermodynamic cycle. In arid area, it could induce conflicts of use on a more fundamental resource than electricity. This fact highlights the need to develop alternatives dry cooling technologies but equally effective. The solar field represents 50% of the investment cost of a CSP plant to be used only daily for the heat production needed for the thermodynamic cycle. The approach of the project is to use this huge area as macro-heat exchanger with its surrounding environment through a coupled heat transfer with the ambient air (convective) and with outer space at 3K (radiative). After validating the compatibility of solar field materials for a such application, these research works has shown experimentally that in addition to extract the waste heat of the thermodynamic cycle, it could also produce cold by night radiative cooling. An innovative alternative solution for cooling CSP plants offering two new features to their already existing solar field for the benefit of its paying off.

Recently, the supercritical carbon dioxide (s-CO2) Brayton cycle has been identified as a promising candidate for solar-thermal energy conversion due to its potentially high thermal efficiency (50%, for turbine inlet temperatures of ~ 1000 K). Realization of such a system requires development of solar receivers which can raise the temperature of s-CO2 by over 200 K, to a receiver outlet temperature of 1000 K. Volumetric receivers are an attractive alternative to tubular receivers due to their geometry, functionality and reduced thermal losses. A concept of a ceramic pressurized volumetric receiver for s-CO2 has been developed in this work. Computational Fluid Dynamics (CFD) analysis along with a Discrete Ordinate method (DOM) radiation heat transfer model has been carried out, and the results for temperature distribution in the receiver and the resulting thermal efficiency are presented. Issues regarding material selection for the absorber structure, window, coating, receiver body and insulation are also addressed. A modular small scale prototype with 0.5 kWth solar heat input has been designed. The design of a small scale s-CO2 loop for testing this receiver module is also presented in this work. There is a lot of ongoing investigation for design and simulation of different configurations of heat exchangers and solar receivers using s-CO2 as the working fluid, in which wall temperatures up to 1000 K are encountered. While CO2 is considered to be transparent as far as solar radiation spectrum is concerned, there may be considerable absorption of radiation in the longer wavelength range associated with radiation emission from the heated cavity walls and tubes inside the receivers. An attempt has been made, in this study, to include radiation modelling to capture the effect of absorption bands of s-CO2 and the radiative heat transfer among the equipment surfaces. As a case study, a numerical study has been performed to evaluate the contribution of radiative heat transfer as compared to convection and conduction, for s-CO2 flow through a circular pipe. The intent is to provide a guideline for future research to determine the conditions for which radiation heat transfer modelling inside the pipe can be significant, and what errors can be expected otherwise. The effect of parameters such as Reynolds number, pipe diameter, length to diameter ratio, wall emissivity and total wall heat flux has been studied. The effect of radiation modelling on wall temperatures attained for certain amount of heat flux to be transferred to s-CO2 is also studied. The resulting temperature distribution, in turn, affects the estimation of heat loss to the environment