Laser-driven plasma accelerators can produce high-energy, high peak current ion beams by irradiating solid materials with ultra-intense laser pulses. This innovative concept attracts a lot of attention for various multidisciplinary applications as a compact and energy-efficient alternative to conventional accelerators. The maturation of plasma accelerators from complex physics experiments to turnkey particle sources for practical applications necessitates breakthroughs in the generated beam parameters, their robustness and scalability to higher repetition rates and efficiencies. This thesis investigates viable optimisation strategies for enhancing ion acceleration from thin foil targets in ultra-intense laser-plasma interactions. The influence of the detailed laser pulse parameters on plasma-based ion acceleration has been systematically investigated in a series of experiments carried out on two state-of-the-art high-power laser systems. A central aspect of this work is the establishment and integration of laser diagnostics and operational techniques to advance control of the interaction conditions for maximum acceleration performance. Meticulous efforts in continuously monitoring and enhancing the temporal intensity contrast of the laser system, enabled to optimise ion acceleration in two different regimes, each offering unique perspectives for applications. Using the widely established target-normal sheath acceleration (TNSA) scheme and adjusting the temporal shape of the laser pulse accordingly, proton energies up to 70 MeV were reliably obtained over many months of operation. Asymmetric laser pulses, deviating significantly from the standard conditions of an ideally compressed pulse, resulted in the highest particle numbers and an average energy gain ≥ 37 %. This beam quality enhancement is demonstrated across a broad range of parameters, including thickness and material of the target, laser energy and temporal intensity contrast. To overcome the energy scaling limitations of TNSA, the second part of the thesis focuses on an advanced acceleration scheme occurring in the relativistically induced transparency (RIT) regime. The combination of thin foil targets with precisely matched temporal contrast conditions of the laser enabled a transition of the initially opaque targets to transparency upon main pulse arrival. Laser-driven proton acceleration to a record energy of 150 MeV is experimentally demonstrated using only 22 J of laser energy on target. The low-divergent high-energy component of the accelerated beam is spatially and spectrally well separated from a lower energetic TNSA component. Start-to-end simulations validate these results and elucidate the role of preceding laser light in pre-expanding the target along with the detailed acceleration dynamics during the main pulse interaction. The ultrashort pulse duration of the laser facilitates a rapid succession of multiple known acceleration regimes to cascade efficiently at the onset of RIT, leading to the observed beam parameters and enabling ion acceleration to unprecedented energies. The discussed acceleration scheme was successfully replicated at two different laser facilities and for different temporal contrast levels. The results demonstrate the robustness of this scenario and that the optimum target thickness decreases with improved laser contrast due to reduced pre-expansion. Target transparency was found to identify the best-performance shots within the acquired data sets, making it a suitable feedback parameter for automated laser and target optimisation to enhance stability of plasma accelerators in the future. Overall, the obtained results and described optimisation strategies of this thesis may become the guiding step for the further development of laser-driven ion accelerators.:1 Introduction 1.1 Motivation 1.2 Thesis outline 2 Fundamentals of laser-matter interactions 2.1 Plasma 2.1.1 Plasma properties 2.1.2 Dispersion relation of a plasma 2.1.3 Laser propagation in a plasma 2.2 Laser-matter interactions 2.2.1 Ionisation processes 2.2.2 Electron dynamics in the laser field 2.2.3 Ponderomotive force 2.2.4 Plasma heating processes 2.3 Laser-driven ion acceleration mechanisms 2.3.1 Target normal sheath acceleration 2.3.2 Radiation pressure acceleration 2.3.3 Acceleration in the relativistically induced transparency regime 3 Methodology for high-power laser experiments 3.1 High-power lasers 3.1.1 High-power laser techniques 3.1.2 Temporal contrast of high-power laser systems 3.1.3 DRACO laser system 3.1.4 J-KAREN-P laser system 3.2 Experimental Area 3.2.1 Short-f chamber at HZDR 3.2.2 Short-f chamber at KPSI 3.3 Targets 3.4 Optical diagnostic 3.4.1 Transmitted and reflected laser light 3.4.2 Spectral phase measurements 3.5 Particle diagnostic 3.5.1 Thomson parabola spectrometer 3.5.2 Time of flight measurements 3.5.3 Spatial proton beam profiler 3.5.4 Radiochromic films 3.5.5 Nuclear activation measurements 4 Optimisation of sheath acceleration for high-quality proton beams 4.1 Introduction 4.2 Temporal contrast at experimental environment 4.3 Plasma mirror 4.3.1 Plasma mirror implementation at DRACO-PW 4.3.2 Plasma mirror characterisation at DRACO-PW 4.4 Temporal pulse shaping by spectral phase modification 4.4.1 Theory on temporal pulse shaping 4.4.2 Experimental realisation and results 4.5 Proton acceleration under optimised temporal contrast conditions 4.6 Experimental results 4.7 Discussion on numerical simulations 4.8 Conclusions 5 Enhanced ion acceleration in the relativistic transparency regime 5.1 Introduction 5.2 Experimental setup using the J-KAREN-P laser 5.3 Experimental results 5.4 Laser-induced breakdown and target pre-expansion 5.5 Elucidating ion acceleration in the relativistically induced transparency regime 5.5.1 Details on simulation methodology 5.5.2 Simulation results 5.6 Acceleration in the RIT regime for modified temporal contrast 5.6.1 Experimental setup using the DRACO-PW laser 5.6.2 Experimental results using the DRACO-PW laser 5.6.3 Simulation results for modified temporal contrast 5.7 Conclusions 6 Ion acceleration beyond the 100 MeV frontier from cascading acceleration schemes 6.1 Introduction 6.2 Experimental setup 6.3 Experimental results 6.3.1 Analysis of acceleration performance 6.3.2 Spatial proton beam profile 6.3.3 Nuclear activation measurement 6.3.4 Scaling of maximum proton energy 6.4 Numerical simulations 6.4.1 Simulation setup 6.4.2 Simulation results & discussion 6.5 Conclusions 7 Summary and outlook Appendix References

<p>Predmet ove doktorske disertacije je definisanje metoda i procedure<br />za procenu veka konstrukcije tornja postrojenja za istraživanje nafte<br />i gasa. Dati su rezultati eksperimentalnih istraživanja radi analize<br />otpornosti prema prslinama pri statičkom i pri promenljivom<br />opterećenju eksploatisanog i novog materijala konstrkcije tornja<br />postrojenja za istraživanje nafte i gasa.</p> / <p>The topic of this doctoral dissertation is definition methods and proceduries for an<br />analysis of an assessmen life of construction derrick plant for investigation oil<br />and gas. The results of experimental investigation performed for the analysis<br />of crack resistance under static and under variable loading eksploatacion<br />and new of materials of construction derrick plant for investigation oil and gas.</p>

Introdução: A densidade energética (DE) de alimentos e dietas é apontada como importante fator na regulação do peso corporal e está intimamente relacionada ao consumo energético. Objetivos: Estimar a DE de refeições ofertadas em amostra de empresas inscritas no Programa de Alimentação do Trabalhador (PAT), e analisar a DE da dieta de trabalhadores da cidade de São Paulo e sua associação com características sócio-demográficas. Métodos: A dissertação é composta por dois manuscritos, que analisaram a DE utilizando como métodos de cálculo: a inclusão de todos os alimentos sólidos e das bebidas, excluindo apenas água (DE1); inclusão de todos os alimentos sólidos e bebidas calóricas que contém, no mínimo, 5 kcal/100g (DE2); e a inclusão de todos os alimentos sólidos e exclusão de todas as bebidas (DE3). O primeiro manuscrito avaliou refeições de 21 empresas, pelos métodos DE1 e DE3. Os valores para energia e peso dos alimentos/bebidas foram obtidos pela avaliação do cardápio do almoço em três dias consecutivos. Utilizaram-se testes não-paramétricos nas análises estatísticas. O segundo manuscrito avaliou a dieta de 852 trabalhadores, por meio de recordatório de 24 horas, considerando os três métodos de cálculo da DE. Na análise da relação entre DE e variáveis sócio-demográficas utilizou-se regressão linear. Resultados: Para as refeições oferecidas, a mediana da DE1 foi 1,10 kcal/g e da DE3 foi 1,43 kcal/g. Para a dieta dos trabalhadores, os valores observados foram 1,18 kcal/g (+0,08), 1,22 kcal/g (+0,08) e 1,73 kcal/g (+0,16), considerando os métodos de cálculo DE1, DE2 e DE3, respectivamente. Nos modelos múltiplos de regressão, apenas a variável idade apresentou associação negativa com todos os métodos de DE. Para a DE3, houve incremento da DE para indivíduos não-brancos. Conclusão: Observou-se que a densidade energética das refeições oferecidas pelas empresas estudadas, assim como a dieta dos trabalhadores, em especial dos mais jovens, apresentaram valores elevados. Esses achados sinalizam a necessidade de intervenções nutricionais para promoção de dietas com menor densidade energética, a fim de prevenir a obesidade entre trabalhadores / Introduction: Energy density (ED) of food and diets is considered as an important factor in the regulation of body weight and is intimately tied to energy intake. Aims: To estimate ED of meals offered in a sample of companies enrolled in the Workers Food Program (WFP), and to analyze ED of the diet of workers from the city of São Paulo and its association with socio-demographic characteristics. Methods: The dissertation consists in two manuscripts, which have analyzed ED utilizing as methods of calculation: including all solid food and beverages, excluding water (ED1); including all solid food and beverages containing at least 5 kcal/100g (ED2); including all solid food and excluding all beverages (ED3). The first manuscript evaluated meals from 21 companies, using methods ED1 and ED3. The values for energy and weight of food/beverages were obtaining through the evaluation of the lunch menu during three consecutive days. Non-parametric tests were used for the statistical analyses. The second manuscript evaluated the diet of 852 workers using a 24-hour recall, taking into account the three methods for calculating ED. In the analysis of the relation between ED and socio-demographic variables linear regression was used. Results: For the meals the median of ED1 was 1.10 kcal/g and ED3 1.43 kcal/g. For the workerss diet the ED values observed were 1.18 kcal/g, 1.22 kcal/g and 1.73 kcal/g, considering respectively ED1, ED2, ED3 methods. In the multiple regression models only the age variable was maintained in the final model and showed inverted association with all methods of ED. For ED3 there was an increase of ED for non-white individuals. Conclusion: It was observed that both the energy density of the meals offered by the companies as well as the energy density of the workerss diet, in special the younger ones, showed high values. These findings point out to the necessity of nutritional interventions for promoting diets with lower energy density in order to prevent workerss overweight

Made available in DSpace on 2017-07-24T19:22:35Z (GMT). No. of bitstreams: 1 ANNA LUIZA SZESZ.pdf: 3989892 bytes, checksum: 237bfbd8af89362f6139a3c445f884d8 (MD5) Previous issue date: 2014-02-25 / This study evaluated, the intensity of light transmitted through a translucent fiber post ( Whitepost DC n° 2) using an experimental system and the effect of different densities of light energy in adhesive properties: degree of conversion within the hybrid layer (DC), nanoleakage (NL) and bond strength (μTBS) of two adhesive systems to dentin (Ambar [AM] and Excite DSC [EX]). The roots of 72 human premolars were prepared endodontically and divided into groups (n=6) according to the combination of factors: adhesive system (AM and EX) and energy density (16, 48 and 288 J/cm²). After cementing fiber post the roots with fiber post were subjected to μTBS (push-out) (n = 7) in a universal testing machine (0.5 mm/min). DC analysis (%) in situ (n = 2) was made by micro -Raman spectroscopy and NL was evaluated by SEM after immersing the samples in 50% silver nitrate (n=3). Data from the μTBS, NL, and DC of each adhesive were analyzed by 3-way repeated measures ANOVA (adhesive vs. Energy density vs. root third) and Tukey test (α = 0.05) . To measure the intensity of light transmitted through the post, the measuring device consisted of a light beam pulsed laser focusing perpendicular to the bottom surface of the post, and in the direction parallel to the axis of the post detector capable of measuring the scattered light at the post. To simulate the variation of light intensity, filters were used in this system with optical density varying the light intensity of 100, 25 and 10%. The results of μTBS (MPa) showed a significant difference for the middle and apical (p <0.05) thirds when an increase in energy density from 16 to 48 and 288 J/cm²respectively. The DC (%) significantly increased the density of 288 J/cm² in the middle and apical thirds compared the same with the lower energy density of 16 J/cm² (p < 0.05). The NL (%) decreases significantly from the energy density of 48 J/cm² in the middle and apical (p thirds < 0.05) and remained constant for the density of 288 J/cm² (p > 0.05), in general, none of the tests results showed a significant difference when the cervical third was evaluated . Regarding the results of the intensity of light scattered by the post, light intensity reduced to 45,5% in the cervical region, to 14,2% and 5,3% in the middle and apical thirds, respectively. As for simulating the variation of light intensity, it was observed that the increase of the intensity of light incident on the base of the cervical post provides a gain of intensity of light reaching the apical level. / Este estudo avaliou, através de um sistema experimental, a intensidade de luz transmitida por um pino de fibra translúcido (Whitepost DC n°2) e o efeito de diferentes densidades de energia da luz nas propriedades adesivas: grau de conversão no interior da camada híbrida (GC), nanoinfiltração (NI) e resistência de união (RU) à dentina de dois sistemas adesivos (Ambar [AM] e Excite DSC [EX]). As raízes de 72 pré-molares humanos foram preparadas endodonticamente e divididas em grupos (n=6) de acordo com a combinação dos principais fatores: sistema adesivo (AM e EX), e densidade de energia (16, 48 e 288 J/cm²). Após cimentação dos pinos de fibra, foi testado a RU (push-out) (n=7) em uma máquina de ensaios universal (0,5 mm/min). A análise do GC (%) in situ (n=2) foi feita através da espectroscopia micro-Raman e a NI foi avaliada por MEV após a imersão das amostras em 50% em nitrato de prata (n=3). Os dados de RU, GC e NI de cada adesivo foram analisados por ANOVA de 3 fatores de medidas repetidas (adesivo vs. densidade de energia vs. terço radicular) e teste de Tukey (α = 0,05). Para mensuração da intensidade de luz transmitida pelo pino, o sistema era constituído por um feixe de luz laser pulsado incidindo perpendicularmente a superfície da base do pino, e na direção paralela ao eixo do pino um detector capaz de mensurar a luz espalhada no pino. Para simular a variação da intensidade de luz foram utilizados junto a esse sistema filtros de densidade óptica, variando a intensidade de luz em 100, 25 e 10%. Os resultados de RU (MPa) demonstraram diferença significativa para os terços médio e apical (p < 0,05) quando houve aumento da densidade de energia de 16 para 48 e 288 J/cm² respectivamente. O GC (%) aumentou significativamente na densidade de 288 J/cm² nos terços médio e apical quando comparado os mesmos terços com a menor densidade de energia 16 J/cm² (p <0,05). A NI (%) diminui significativamente a partir da densidade de energia de 48 J/cm² nos terços médio e apical (p < 0,05) e se manteve constante para a densidade de 288 J/cm² (p > 0,05). Em geral, nenhum dos testes apresentaram resultados com diferença significativa quando o terço cervical foi avaliado. Em relação aos resultados da intensidade da luz espalhada pelo pino observamos que na região cervical a intensidade de luz reduz para 45,5 % no terço médio para 14,2 % e para apical 5,3%. Quanto a simulação da variação da intensidade da luz, foi possível observar que o aumento da intensidade de luz incidente na base cervical do pino proporciona um ganho de intensidade de luz que chega ao nível apical.

O espalhamento de ondas eletromagnéticas por partículas isoladas, com propriedades ópticas e formatos arbitrários, encontra aplicações nas mais diversas áreas do conhecimento. Usualmente, o espalhamento eletromagnético é investigado via grandezas auferidas na região de campo distante. Para partículas inomogêneas, no entanto, as ressonâncias nas seções de choque de espalhamento podem não corresponder a um aumento de intensidade do campo eletromagnético nas vizinhanças imediatas da partícula (região de campo próximo). Esse efeito pode ser induzido em nanopartículas dielétricas com revestimentos plasmônicos e foi recentemente explicado em termos da ressonância de Fano. Essa ressonância resulta da interferência entre um modo eletromagnético não ressonante (processo de fundo) e um modo discreto ressonante (ressonância de plásmon), produzindo um formato assimétrico de linha espectral. Para o entendimento de como os modos de superfície no campo próximo acoplam-se às ressonâncias nas seções de choque, é necessário o cálculo de funcionais dos campos eletromagnéticos internos às partículas ou em suas vizinhanças imediatas. Neste estudo, calculamos a energia eletromagnética no interior de centros espalhadores nas geometrias esférica e cilíndrica. Fazemos aqui o vínculo dos campos internos às grandezas de espalhamento no campo distante via seção de choque de absorção e conservação de energia. Aplicamos nossos resultados a metamateriais dispersivos, estudando as propriedades do espalhamento por esferas revestidas e por esferas quirais, no regime de refração negativa, e por cilindros revestidos sob incidência oblíqua de radiação. Mediante a energia interna às partículas, demonstramos novos efeitos de aumento de intensidade de campo interno fora da ressonância de espalhamento e fornecemos resultados analíticos para a análise dessas ressonâncias, tanto em espalhamento simples quanto múltiplo. / Electromagnetic wave scattering by single particles with both shapes and optical properties arbitrary finds applications in several areas of knowledge. Usually, the electromagnetic scattering is investigated via measured quantities in the far-field region. However, for inhomogeneous particles, resonances in scattering cross sections may not correspond to the electromagnetic field enhancement in the vicinity of a particle (near-field). This effect can be induced in dielectric nanoparticles with plasmonic coatings, and it has recently been explained in terms of the Fano resonance. The Fano resonance results from the interference between a non-resonant electromagnetic mode (background or continuous) and a resonant discrete mode (localized plasmon resonance), leading to an asymmetric lineshape. To understand how the surface modes in the near-field are connected to the cross section resonances, functionals of the electromagnetic fields within scatterers or in their vicinity are required. In this study, we calculate the electromagnetic energy inside scatterers in both cylindrical and spherical geometries. We obtain a connection between the internal energy and the scattering quantities in the far-field via absorption cross section and energy conservation. We apply our results to dispersive metamaterials, studying scattering properties of coated and chiral spheres in the negative refraction regime, and coated cylinders under oblique incidence of radiation. By the electromagnetic energy inside particles, we demonstrate new off-resonance field enhancement effects and provide analytical tools to analyze these resonances in both single and multiple scattering regimes.

Ce travail de thèse suit l'apparition récente de ces nouvelles sources intenses et courtes de rayonnement dans la gamme X/XUV que sont les lasers X/XUV à électrons libres (XFEL). Contrairement aux sources optiques qui déposent principalement leur énergie via les électrons libres, les photons X/XUV déposent leur énergie dans la matière par la photoionisation de couches internes avec éjection de photo-électrons, suivie par l'éjection d'électrons Auger et d'électrons de recombinaison à trois corps dans la distribution d'électrons libres. Le chauffage se fait donc par l'intermédiaire de la structure atomique. La forte intensité des XFELs permet de faire jusqu'à un trou par atome dans un solide produisant ainsi, sur une échelle femtoseconde, un état exotique fortement hors-équilibre appelé solide creux. Cet état exotique instable se désexcite via un ensemble de processus atomiques élémentaires. Nous nous sommes intéressés dans cette thèse au développement d'outils permettant de calculer la cinétique des populations atomiques, couplée à la cinétique des électrons libres, pendant la transition à densité ionique constante, de solide à plasma dense en passant par l'état de solide creux, induit par le rayonnement XFEL irradiant une cible solide. Tout le défi ici a été de calculer cette cinétique couplée hors-équilibre entre ces états de la matière de nature très différente. Pour répondre a ce défi nous avons développé deux modèles cinétiques d'interaction XFELsolide, pour lesquels la description d'un solide comme un plasma froid dégénéré nous a permis d'utiliser une même approche plasma pendant l'ensemble de la transition du solide au plasma. L'ensemble de la physique atomique HETL d'intérêt ayant lieu à densité du solide, bien avant la détente de la matière, nous avons développé deux codes associés à ces modèles pour une utilisation à densité ionique constante. Pour aborder l'étude nous nous sommes d'abord concentrés sur la cinétique des électrons liés en supposant une distribution d'électrons libres à l'équilibre (ce qui suppose une thermalisation instantanée des électrons libres). Dans le cadre de l'approche de plasma dense étendue jusqu'au solide, nous avons développé un modèle collisionnel-radiatif généralisé. Cette généralisation passe par l'identification d'un lien entre état solide et plasma au niveau des processus atomiques élémentaires. Le code développé à partir de ce modèle nous a permis d'étudier des résultats expérimentaux et ainsi d'améliorer notre description des effets de densités dans les plasmas denses. Dans une seconde partie nous avons ajouté à l'étude la cinétique des électrons libres en considérant une distribution d'électrons libres hors-équilibre. Le code associé, basé sur la discrétisation de cette distribution et son couplage avec les états liés, nous a permis d'étudier le rôle des processus atomiques élémentaires dans la thermalisation de la distribution d'électrons libres. / This work follows the recent development of the free electron lasers in the X-ray and XUV-ray range (XFEL). Unlike optical sources that deposit their energy via the free electrons, the X/XUV photons deposit their energy directly via photoionization of inner shell electrons with the ejection of photo-electrons, followed by the ejection of Auger electrons and three body recombination electrons in the free electron distribution. The matter is thus heated via the atomic structure. The high XFEL intensity allows one to make up to one hole per atom in a solid, thus producing, on a femtosecond time scale, an exotic state, highly out of equilibrium, called hollow cristal. This unstable exotic state deexcite via a set of elementary atomic processes. In this work we were interested in the development of tools to calculate the atomic population kinetics, coupled to the free electron kinetics, during the transition at constant ionic density, from solid to dense plasma, induced by an XFEL irradiating a solid target. The goal here was to calculate this out of equilibrium coupled kinetics between states of matter having a very different nature. To address this problem we have developed two kinetics models of XFEL interaction with solids. In both these models the description of the solid as a cold degenerated plasma allowed us to use the same plasma approach during all the solid-plasma transition. Considering the fact that all the atomic physics takes place at solid density, way before the matter relaxation, we have developed two codes, associated with these two models, for a use at constant ionic density. To approach this study, we first focused on the bound electron kinetics assuming a free electron distribution at equilibrium (i.e. hypothesis of instantaneous thermalization of the free electrons). In the framework of the dense plasma approach extended up to the solid state, we have developed a generalized collisional radiative model. This generalization goes through the identification of a link between the solid state and the plasma state for the elementary atomic processes. The code associated with this model allowed us to study experimental results and to improve our description of the density effects in dense plasmas. In a second part the free electron kinetics is included in the model with a free electron distribution out of thermodynamic equilibrium. The associated code, based on the discretization of this distribution and its coupling with bound atomic states allowed us to study the role of the atomic elementary processes in the free electron distribution thermalization.

Introdução: A densidade energética (DE) de alimentos e dietas é apontada como importante fator na regulação do peso corporal e está intimamente relacionada ao consumo energético. Objetivos: Estimar a DE de refeições ofertadas em amostra de empresas inscritas no Programa de Alimentação do Trabalhador (PAT), e analisar a DE da dieta de trabalhadores da cidade de São Paulo e sua associação com características sócio-demográficas. Métodos: A dissertação é composta por dois manuscritos, que analisaram a DE utilizando como métodos de cálculo: a inclusão de todos os alimentos sólidos e das bebidas, excluindo apenas água (DE1); inclusão de todos os alimentos sólidos e bebidas calóricas que contém, no mínimo, 5 kcal/100g (DE2); e a inclusão de todos os alimentos sólidos e exclusão de todas as bebidas (DE3). O primeiro manuscrito avaliou refeições de 21 empresas, pelos métodos DE1 e DE3. Os valores para energia e peso dos alimentos/bebidas foram obtidos pela avaliação do cardápio do almoço em três dias consecutivos. Utilizaram-se testes não-paramétricos nas análises estatísticas. O segundo manuscrito avaliou a dieta de 852 trabalhadores, por meio de recordatório de 24 horas, considerando os três métodos de cálculo da DE. Na análise da relação entre DE e variáveis sócio-demográficas utilizou-se regressão linear. Resultados: Para as refeições oferecidas, a mediana da DE1 foi 1,10 kcal/g e da DE3 foi 1,43 kcal/g. Para a dieta dos trabalhadores, os valores observados foram 1,18 kcal/g (+0,08), 1,22 kcal/g (+0,08) e 1,73 kcal/g (+0,16), considerando os métodos de cálculo DE1, DE2 e DE3, respectivamente. Nos modelos múltiplos de regressão, apenas a variável idade apresentou associação negativa com todos os métodos de DE. Para a DE3, houve incremento da DE para indivíduos não-brancos. Conclusão: Observou-se que a densidade energética das refeições oferecidas pelas empresas estudadas, assim como a dieta dos trabalhadores, em especial dos mais jovens, apresentaram valores elevados. Esses achados sinalizam a necessidade de intervenções nutricionais para promoção de dietas com menor densidade energética, a fim de prevenir a obesidade entre trabalhadores / Introduction: Energy density (ED) of food and diets is considered as an important factor in the regulation of body weight and is intimately tied to energy intake. Aims: To estimate ED of meals offered in a sample of companies enrolled in the Workers Food Program (WFP), and to analyze ED of the diet of workers from the city of São Paulo and its association with socio-demographic characteristics. Methods: The dissertation consists in two manuscripts, which have analyzed ED utilizing as methods of calculation: including all solid food and beverages, excluding water (ED1); including all solid food and beverages containing at least 5 kcal/100g (ED2); including all solid food and excluding all beverages (ED3). The first manuscript evaluated meals from 21 companies, using methods ED1 and ED3. The values for energy and weight of food/beverages were obtaining through the evaluation of the lunch menu during three consecutive days. Non-parametric tests were used for the statistical analyses. The second manuscript evaluated the diet of 852 workers using a 24-hour recall, taking into account the three methods for calculating ED. In the analysis of the relation between ED and socio-demographic variables linear regression was used. Results: For the meals the median of ED1 was 1.10 kcal/g and ED3 1.43 kcal/g. For the workerss diet the ED values observed were 1.18 kcal/g, 1.22 kcal/g and 1.73 kcal/g, considering respectively ED1, ED2, ED3 methods. In the multiple regression models only the age variable was maintained in the final model and showed inverted association with all methods of ED. For ED3 there was an increase of ED for non-white individuals. Conclusion: It was observed that both the energy density of the meals offered by the companies as well as the energy density of the workerss diet, in special the younger ones, showed high values. These findings point out to the necessity of nutritional interventions for promoting diets with lower energy density in order to prevent workerss overweight

Les supercondensateurs sont des dispositifs de stockage électrochimique de l’énergie très intéressants lorsque des pics de puissance sont mis en jeu. Toutefois, leur densité d’énergie volumique est la principale limite pour leur intégration, en particulier, dans des systèmes de transport terrestre. L’utilisation de matériaux d’électrode ayant un comportement pseudocapacitif et des masses volumiques élevées permettrait d’améliorer la densité d’énergie volumique des supercondensateurs. Avec cet objectif, des dispositifs à base des matériaux de la famille Ba0,5Sr0,5CoxFe1-xO3-δ, nommés BSCFs, ont été développés dans le cadre de cette thèse. Plusieurs compositions de cette famille d’oxydes ont été préparées par un procédé glycine-nitrate et ont été testés comme matériau actif d’électrode positive en milieu aqueux neutre. La capacité volumique de ces matériaux s’avère être beaucoup plus élevée que celle des carbones activés utilisés dans les supercondensateurs commerciaux. Elle a montré également dépendre de la composition en cobalt et en fer, du régime de charge, de la nature de l’électrolyte… Le mécanisme de stockage de charges dans ces matériaux a été exploré grâce à des techniques in situ (absorption des rayons X) et operando (diffraction des rayons X) effectuées aux synchrotrons SOLEIL (France) et SPring-8 (Japon). Enfin, des dispositifs associant une électrode positive à base de BSCF et du carbone activé ou FeWO4 en tant qu’électrode négative ont démontré l’intérêt d’intégrer de tels matériaux pour améliorer la densité d’énergie volumique des supercondensateurs. / Supercapacitors are attractive electrochemical energy storage devices for high power applications. However, volumetric energy density is the main limitation for their integration in such applications as terrestrial transport systems. The use of high density pseudocapacitive oxides as electrode material could lead to a volumetric energy density improvement. With this aim, materials from Ba0,5Sr0,5CoxFe1-xO3-δ family, so called BSCFs, have been studied. Several compositions have been prepared and evaluated as positive electrode materials in aqueous neutral electrolyte. Volumetric capacitances have shown to be greater than those of activated carbons, already used in marketed supercapacitors. They have also shown to depend on cobalt and iron ratio, charge rate, electrolyte composition... The study of the charge storage mechanism in these materials has been investigated thanks to in situ (X-Ray absroption spectroscopy) and operando (X-Ray diffraction) technics performed at SOLEIL (France) and SPring-8 (Japan) synchrotron facilities. Finally, devices coupling BSCF based positive electrode material with activated carbon or FeWO4 based negative electrode materials have demonstrated the added value of such materials to improve the volumetric energy density of supercapacitors.

To enable future environmentally friendly access to space by means of solid rocket propulsion a viable replacement to the hazardous ammonium perchlorate oxidizer is needed. Ammonium dinitramide (ADN) is one of few such compounds currently known. Unfortunately compatibility issues with many polymer binder systems and unexplained solid-state behavior have thus far hampered the development of ADN-based propellants. Chapters one, two and three offer a general introduction to the thesis, and into relevant aspects of quantum chemistry and polymer chemistry. Chapter four of this thesis presents extensive quantum chemical and spectroscopic studies that explain much of ADN’s anomalous reactivity, solid-state behavior and thermal stability. Polarization of surface dinitramide anions has been identified as the main reason for the decreased stability of solid ADN, and theoretical models have been developed to explain and predict the solid-state stability of general dinitramide salts. Experimental decomposition characteristics for ADN, such as activation energy and decomposition products, have been explained for different physical conditions. The reactivity of ADN towards many chemical groups is explained by ammonium-mediated conjugate addition reactions. It is predicted that ADN can be stabilized by changing the surface chemistry with additives, for example by using hydrogen bond donors, and by trapping radical intermediates using suitable amine-functionalities. Chapter five presents several conceptual green energetic materials (GEMs), including different pentazolate derivatives, which have been subjected to thorough theoretical studies. One of these, trinitramide (TNA), has been synthesized and characterized by vibrational and nuclear magnetic resonance spectroscopy. Finally, chapter six covers the synthesis of several polymeric materials based on polyoxetanes, which have been tested for compatibility with ADN. Successful formation of polymer matrices based on the ADN-compatible polyglycidyl azide polymer (GAP) has been demonstrated using a novel type of macromolecular curing agent. In light of these results further work towards ADN-propellants is strongly encouraged. / QC 20101103

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