Preocupações com sustentabilidade ambiental são recorrentes tanto no meio acadêmico, como no meio empresarial. Elas ecoam ao se pensar no crescimento econômico chinês e nos impactos das atividades produtivas no meio ambiente. A China é o país emergente com as maiores taxas de crescimento econômico no mundo, porém sua imagem também reflete sua vulnerabilidade com relação à ecologia. Tendo isso em consideração e procurando compreender como isso repercute nas operações internacionais, esta tese estuda os determinantes estratégicos das empresas chinesas em operação no Brasil, pelas lentes teóricas do tripé da estratégia. A sustentabilidade ambiental se operacionalizou em ecoeficiência, termo desdobrado em eco-inovação, eco-reputação e manufatura verde. Dado que os aspectos estratégicos direcionam as ações empresariais, isto se torna ainda mais complexo ao se analisar a operação internacional, uma vez que além dos aspectos internos e de mercado, a empresa é influenciada por forças institucionais relacionados com seu mercado de origem e com o mercado de destino das vendas externas. Esta tese inova ao relacionar aspectos do tripé da estratégia com as estratégias de ecoeficiência de empresas chinesas no Brasil. São utilizadas técnicas quantitativas para testar as hipóteses. A análise é feita utilizando modelo de equações estruturais, com o software SmartPLS v3. Os resultados indicam que há associação positiva entre os recursos internos da empresa e ações de ecoeficiência nos seus três desdobramentos (eco-inovação, eco-reputação e manufatura verde). No caso da visão baseada na indústria, encontrou-se associação positiva com manufatura verde e eco-reputação, mas não com as iniciativas de eco-inovação. Os aspectos institucionais do mercado brasileiro não puderam ser associados com nenhuma das iniciativas de ecoeficiência. Esta tese contribui para o entendimento de determinantes estratégicos na adoção de iniciativas ambientais, ao indicar a importância dos recursos na implantação dessas estratégias. Não se confirma a importância da vertente institucional no modelo teórico-conceitual, o que mostra limitação à extensão dessa teoria. Os resultados, do ponto de vista gerencial, mostram que as forças de mercado estimulam as empresas a empreender em iniciativas de eco-reputação e os processos de manufatura. Contudo, verifica-se que os aspectos de eco-inovação nas empresas chinesas ainda não foram influenciados pelas demandas do mercado brasileiro. / Concerns about environmental sustainability are recurrent both in academy and in business. This concern echoes especially because of the impact of Chinese productive activities on the environment. China is an emerging country with the highest economic growth rates in the world, but its image also reflects their vulnerability on ecological issues. Taking this into consideration, this thesis studies the strategic determinants of Chinese companies operating in Brazil by the theoretical lenses of strategic tripod. Environmental sustainability is operationalized into eco-efficiency, a term translated into eco-innovation, eco-reputation and green manufacturing. To the extent that strategy directs business actions, it becomes even more complex when analyzing the international operation, as well as internal aspects and market, the company is influenced by institutional forces from home market and the target market of foreign sales. This thesis contributes to relate aspects of the strategy tripod with the eco-efficiency strategies of Chinese companies in Brazil. This thesis contributes to relate the strategy tripod with the eco-efficiency strategies of Chinese companies. To this end, methodology was quantitative, with data collected and examined in order to confirm or refute the hypothesis. They were analyzed by structural equation model, with SmartPLS v3 software. The results indicate that there is a positive association between the internal resources and eco-efficiency in its three developments (eco-innovation, eco-green reputation and manufacturing). About the industry-based view, there is a positive association with green manufacturing and eco-reputation, but not with eco-innovation initiatives. Brazilian institutional aspects could not be associated with any of the eco-efficiency strategies. To literature, this thesis contributes to the understanding of strategic determinants on adopting environmental initiatives. It highlights the importance of resources in the implementation of eco strategies. However, tests do not confirm the importance of institutional aspects in the theoretical-conceptual model, which exposes the limited extent of this theory. From the managerial side results show that market forces encourage companies to engage in eco-reputation and green manufacturing process initiatives. However, it appears, according to the data, which aspects of eco-innovation in Chinese companies have not been influenced by the Brazilian market demands.

Preocupações com sustentabilidade ambiental são recorrentes tanto no meio acadêmico, como no meio empresarial. Elas ecoam ao se pensar no crescimento econômico chinês e nos impactos das atividades produtivas no meio ambiente. A China é o país emergente com as maiores taxas de crescimento econômico no mundo, porém sua imagem também reflete sua vulnerabilidade com relação à ecologia. Tendo isso em consideração e procurando compreender como isso repercute nas operações internacionais, esta tese estuda os determinantes estratégicos das empresas chinesas em operação no Brasil, pelas lentes teóricas do tripé da estratégia. A sustentabilidade ambiental se operacionalizou em ecoeficiência, termo desdobrado em eco-inovação, eco-reputação e manufatura verde. Dado que os aspectos estratégicos direcionam as ações empresariais, isto se torna ainda mais complexo ao se analisar a operação internacional, uma vez que além dos aspectos internos e de mercado, a empresa é influenciada por forças institucionais relacionados com seu mercado de origem e com o mercado de destino das vendas externas. Esta tese inova ao relacionar aspectos do tripé da estratégia com as estratégias de ecoeficiência de empresas chinesas no Brasil. São utilizadas técnicas quantitativas para testar as hipóteses. A análise é feita utilizando modelo de equações estruturais, com o software SmartPLS v3. Os resultados indicam que há associação positiva entre os recursos internos da empresa e ações de ecoeficiência nos seus três desdobramentos (eco-inovação, eco-reputação e manufatura verde). No caso da visão baseada na indústria, encontrou-se associação positiva com manufatura verde e eco-reputação, mas não com as iniciativas de eco-inovação. Os aspectos institucionais do mercado brasileiro não puderam ser associados com nenhuma das iniciativas de ecoeficiência. Esta tese contribui para o entendimento de determinantes estratégicos na adoção de iniciativas ambientais, ao indicar a importância dos recursos na implantação dessas estratégias. Não se confirma a importância da vertente institucional no modelo teórico-conceitual, o que mostra limitação à extensão dessa teoria. Os resultados, do ponto de vista gerencial, mostram que as forças de mercado estimulam as empresas a empreender em iniciativas de eco-reputação e os processos de manufatura. Contudo, verifica-se que os aspectos de eco-inovação nas empresas chinesas ainda não foram influenciados pelas demandas do mercado brasileiro. / Concerns about environmental sustainability are recurrent both in academy and in business. This concern echoes especially because of the impact of Chinese productive activities on the environment. China is an emerging country with the highest economic growth rates in the world, but its image also reflects their vulnerability on ecological issues. Taking this into consideration, this thesis studies the strategic determinants of Chinese companies operating in Brazil by the theoretical lenses of strategic tripod. Environmental sustainability is operationalized into eco-efficiency, a term translated into eco-innovation, eco-reputation and green manufacturing. To the extent that strategy directs business actions, it becomes even more complex when analyzing the international operation, as well as internal aspects and market, the company is influenced by institutional forces from home market and the target market of foreign sales. This thesis contributes to relate aspects of the strategy tripod with the eco-efficiency strategies of Chinese companies in Brazil. This thesis contributes to relate the strategy tripod with the eco-efficiency strategies of Chinese companies. To this end, methodology was quantitative, with data collected and examined in order to confirm or refute the hypothesis. They were analyzed by structural equation model, with SmartPLS v3 software. The results indicate that there is a positive association between the internal resources and eco-efficiency in its three developments (eco-innovation, eco-green reputation and manufacturing). About the industry-based view, there is a positive association with green manufacturing and eco-reputation, but not with eco-innovation initiatives. Brazilian institutional aspects could not be associated with any of the eco-efficiency strategies. To literature, this thesis contributes to the understanding of strategic determinants on adopting environmental initiatives. It highlights the importance of resources in the implementation of eco strategies. However, tests do not confirm the importance of institutional aspects in the theoretical-conceptual model, which exposes the limited extent of this theory. From the managerial side results show that market forces encourage companies to engage in eco-reputation and green manufacturing process initiatives. However, it appears, according to the data, which aspects of eco-innovation in Chinese companies have not been influenced by the Brazilian market demands.

The main focus of the research work presented in the thesis is the understanding of structural and conformational reorganizations in hyperbranched and linear polymers. The thesis includes three different investigations: a) the design, synthesis, conformational reorganizations and self-assembly of hyperbranched polymers (HBPs), b) the Raman spectroscopic studies of the melting of polyethylene glycol (PEG), and c) the preparation of functionalized porous polymer films. HBPs are structurally imperfect analogues of the defect-free branched polymers called dendrimers. Dendrimers prepared using a stepwise polymerization methodology will carry all the unreacted B groups at the periphery and therefore modification of these peripheral units with suitable linear segments (e.g. PEG) would naturally generate a core-shell structure. On the other hand, in the case of HBPs, that contain a large number of linear defects, the B groups are distributed throughout the highly branched backbone, and hence modification of these units may not generate a core-shell configuration. However, our earlier studies have demonstrated the unimolecular micelle type behavior (core-shell) of PEG-ylated aromatic HB polyethers in solution. Hence, even though the PEG segments are randomly placed throughout the HBP backbone, the polymer achieves a core-shell configuration through conformational reorganizations; this suggests that the core of HBPs may be flexible and adaptable. In order to further examine this issue, we have investigated the self-assembly of these PEG-ylated HBPs. These polymers were found to organize into uniform nano-aggregates (Figure 1). More interestingly, these aggregates were found to restructure on mica surface when exposed to solvent vapor. This study confirmed the formation of core-shell domains in the PEG-ylated HBPs and the ability of the HB core to reconfigure. Figure 1. Restructuring of nano-aggregates formed from PEG-ylated HBPs on mica surface. As mentioned earlier, the precise control of the placement of functional groups would be impossible in the case of hyperbranched polymers (HBPs); most approaches would result in random placement of the functional entities as the growth of the polymer occurs in a statistically governed manner. Hence, creating Janus hyperbranched structures appears a daunting task. Janus is the name given for facially amphiphilic systems, such as a sphere made by joining a hemisphere with a hydrophobic surface and one with a hydrophilic surface. Since we have demonstrated that the HBP backbone is adaptable, it would be interesting to test the possibility of generating a Janus configuration through reorganization of peripheral segments. Peripherally “clickable” HB polyesters were synthesized using the transesterification polymerization methodology. The peripheral groups were modified with two dissimilar segments, PEG and docosyl (C22 alkyl, DOCO) chains, by azide-yne click reaction using the corresponding azides. The immiscibility of the chains along with the tendency of alkyl chain to crystallize was expected to cause self-segregation of segments at the periphery aided by the reconfiguration of HB core. Melting transition associated with alkyl segments was evident in the DSC thermogram. In addition, the melting enthalpies, normalized with respect to the weight of alkyl segments, were close to that of the C22 alkyl chain for three HBPs with different compositions of DOCO and PEG. This suggests complete phase segregation of segments at the periphery. The behavior of these HBPs at the air-water interface was also investigated. In this experiment a single layer of molecules, deposited at the air-water interface, is compressed and decompressed at a predetermined rate. The surface pressure variation during the compression-decompression cycle reveals the molecular organization at the surface. Stable and reversible isotherms were obtained for these HBPs; which suggested their Janus nature with PEG chains solvated in water and alkyl chains projecting out into air. A change in slope was observed in the isotherm and we have ascribed this to the crystallization of docosyl segments. In order to verify the assignment, quasi-static compression (QSC) experiments were performed. In QSC experiment, the monolayer was rapidly compressed to a required surface area and the drop in surface pressure, as a function of time at this fixed surface area, was recorded. During the rapid compression the molecules may not have adequate time to organize optimally and therefore, holding the area constant often leads to a drop in surface pressure with time. The total pressure-drop after the compression reflects the extent of molecular reorganizations; this, for example, could be due to the crystallization of alkyl segments. In the present study, the extent of pressure drop scaled with the composition of alkyl chains; this proves the assignment and supports the self-segregation of the peripheral segments to generate a Janus configuration (Figure 2). AFM images of the transferred monolayer allowed the estimation of monolayer height, which was roughly in agreement with the expected single molecule dimension. Small angle X-ray scattering experiments (SAXS) on HBPs demonstrated existence of a lamellar morphology in the solid state. Janus structures may be expected to exist as bilayers in the solid state. As expected, the lamellar dimensions estimated were twice the monolayer height observed in AFM images. This confirms the bilayer structure and the Janus configuration of HBPs. We have also investigated the self-assembly of these Janus HBPs in solution and it was found that disk-like aggregates were formed in methanol, whereas vesicles were formed in water by systems that had the appropriate balance of hydrophilic and hydrophobic segments. Figure 2. a) The structure of Janus HBP. b) A cartoon depiction of reconfiguration of randomly functionalized HBP to Janus. c) DSC thermograms showing clear melting and crystallization peaks. d) Langmuir isotherms for Janus HBPs. The change in slope is indicated by orange arrow. e) Quasi-static compression isotherms. The extent of pressure drop for different HBPs (inset). f) The SAXS pattern suggesting lamellar structure in the solid state and a proposed model (inset). It was clear from the study that the incompatibility between segments is the primary reason for the reconfiguration. In order to test the generality of the approach, we have prepared two other types of HBPs: one with PEG and fluorocarbon (FC) and the other with DOCO and FC. These segments were chosen because of their mutual incompatibility. In both these systems, the formation of Janus configuration was similarly confirmed by DSC, SAXS and Langmuir isotherm studies. We have extended these studies to HBPs functionalized with three different immiscible segments (tripod HBPs) namely, PEG, DOCO and FC; in the case of PEG two different molecular weights were used: PEG350 and PEG1000; the latter exhibits a strong tendency to crystallize. Melting transition associated with each of the segments was observed in the DSC experiments. The normalized melting enthalpy of the docosyl domain was found to vary substantially depending on the composition and configuration of HBPs (Janus or tripod). Considering the variation of these values it was concluded that the presence of an immiscible amorphous segment, like PEG350, enhances the phase separation and crystallization of DOCO by providing more flexibility to the core. The presence of one or more immiscible but crystallizable segments (e.g. FC or PEG1000), on the other hand, lead to less effective crystallization. Interfacial behavior of the tripod HBPs, that carry the hydrophilic PEG units, were also studied using Langmuir trough. The tripod HBPs formed clear monolayer at the air-water interface at higher surface pressures (40 mN/m); where the hydrophobic segments, FC and DOCO, oriented away from water into air and PEG segments remained solvated in water. Due to the incompatibility between FC and DOCO, it may be anticipated that these segments also form phase segregated domains. While the AFM images allowed the estimation of monolayer thickness, these domains could not be resolved in the images. Interestingly, the transferred monolayer appeared smoother after thermal annealing. To investigate the reason, contact angle (CA) measurements were performed. It is widely accepted that the contact angle is very sensitive to the structure and chemistry of a few angstrom thick region of the top surface of a monolayer. The water CA on the monolayer before thermal annealing was 84˚ while it increased to 104˚ after annealing. This behavior was attributed to the effective phase segregation and crystallization of FC and DOCO domains. The crystallization causes CF3 end groups to orient normal to the surface and hence increases the water contact angle. The receding contact angle, on the other hand, was found to be substantially smaller (45˚); this large contact angle hysteresis could be indicative of chemical heterogeneity on the surface, and it has been suggested that the presence of small domains of low surface free energy could indeed result in such large contact angle hysteresis. Interestingly, when the film was aged under ambient conditions for 12 h, the contact angle dropped to the initial value of 84˚; re-annealing the film at 75˚C for 12 h again raised the contact angle back to 104˚. This reversible annealing-aging behavior reveals dynamic nature of the monolayer that permits gradual restructuring at the surface (Figure 3). Self-assembly of these tripod hybramers resulted in the formation of unique aggregated structures. Morphology of these aggregates, observed in AFM images, were different from those formed by Janus hybramers. These results provide a clear evidence for the segregation of all the three segments into individual domains -the hypothesized tripod hybramer configuration. Figure 3. AFM images of transferred monolayer of tripod HBP before and after thermal annealing. Contact angle (CA) measured on the corresponding monolayers are shown in the inset. A model proposed for explaining the variation in the appearance of the monolayer (image) and the CA is also provided in the figure. Effective phase segregation of FC and DOCO is proposed the reason for the change. Another interesting question we have investigated as a part of the thesis is the molecular mechanism of melting of PEG. Crystallization of polymer is hypothesized as polymer chains moving down the free energy landscape though sequence of conformational reorganizations into an ordered crystalline (lamellar) state. Such conformational reorganizations also occur during melting. We have attempted to probe conformational dynamics in PEG during its melting using Raman spectroscopy, polarized optical microscopy, DSC and DFT calculations. Single crystal X-ray and vibrational spectroscopic studies have demonstrated helical configuration of PEG chains in the solid state with a gauche O-C-C-O, trans C-C-O-C and trans C-O-C-C conformations. There are three ways in which the PEG-helix can change during heating; one where C-O single bond rotates, second where the C-C rotates and third where both rotate, but the barriers to these rotations are different, as was established by earlier NMR studies. The intensity ratio of two Raman bands, I2880/2850, was found to be sensitive to the configuration about O-C-C-O units along the polymer backbone. An invariant I2880/2850 ratio of ~0.78 was ascribed to the consistent C-C dihedral angle (gauche configuration) during melting. This agrees with the well-known “gauche effect” in ethylene glycol. Prominent spectral changes were also observed in the methylene rocking region (~800 cm-1). In order to gain insight into the new conformers formed during melting, we carried out Gaussian calculations using model conformers. Among helical models considered the heptamer and tetradecamer helix models were found to be most suitable for the solid state helical structure of PEG. The Gaussian calculations using different model conformers revealed that the Raman band at 810 cm-1 corresponds to CH2 rocking vibrations of the gauche C-C-O-C units along the polymer chain; while the band at ~1500 cm-1 region was characteristic of O-C-C-O trans conformer. This agrees with the earlier assignment of 1500 cm-1 band to CH2 scissoring vibrations of PEG in an all-trans configuration. Interestingly, no peak was observed in the 1500 cm-1 region of the Raman spectrum during melting of PEG, but new peaks appeared in the 810 cm-1 region (Figure 4). Hence, it was concluded that C-C bond rotation does not occur during melting of PEG. Thus, our study confirmed that C-O single bond rotation is the molecular mechanism of PEG melting. Figure 4. a) Raman spectra of PEG at different temperatures. b) helical model considered for the study. c) Comparison of the Raman spectrum of molten PEG (2) with calculated spectra of two different models. The dynamics of a system, where the successive changes occur as a function of external perturbation, can be studied using 2D correlation spectroscopy (2D-CoS). 2D-Raman Correlation spectroscopy was employed to study the molecular structural dynamics during the melting of PEG. Conventional rules of 2D-CoS were used to retrieve the order in which the vibrational bands respond to temperature. Vibration at 934 cm-1 corresponding to the amorphous domain of PEG solid state was found to respond to temperature first. As the temperature of the system rises, CH2 rocking (1280 cm-1), CH2 wagging (1472 cm-1) and CH2 scissoring (1124 cm-1) vibrations becomes active and this provides flexibility to the chain. As the polymer chain gains adequate energy (at particular temperature) bond rotation takes place resulting in the transformation of a few TGT segments to GGG segments. On increasing the temperature further more C-O bond rotations occur, leading to destruction of lamellar domains and eventually PEG melts. The final study presented in this thesis deals with the generation of functionalized porous polymer films. Condensation of water droplets during solvent evaporation from a polymer solution, under humid conditions, is known to generate uniformly porous polymer films. We have investigated the possibility of pore formation through water phase separation strategy (Figure 5). In the presence of added surfactants (SDS and CTAB in the present study), the interface of phase separated water droplets and the polymer would naturally become lined with the surfactants and consequently the internal walls of the pores generated, upon removal of the water, could become decorated with the hydrophilic head groups of the surfactant molecules. The size of the pores and their distribution were examined using AFM and IR imaging methods. We have demonstrated that the ATR-IR imaging is an efficient method for analyzing a few nanometer thick surface section of the polymer film (Figure 5e). It was observed that the presence of surfactant is important for the pore formation and irregular pore formation resulted in the absence of surfactant. In addition, both the surfactant concentration and the relative volume fraction of the surfactant solution were found to govern the size of the pores formed. Cloud point measurements suggested that the occurrence of surfactant facilitated the phase separation of water. Although IR imaging possessed inadequate resolution to confirm the presence of surfactants at the inner surface of pores, exchange of the inorganic counter-ion, such as the sodium-ion of sodium dodecyl sulphate (SDS), with suitable ionic organic dyes permitted the unequivocal demonstration of the presence of the surfactants at the interface with confocal fluorescence microscopy (Figure 5f). Figure 5. Schematic depiction of a homogeneous polymer solution (sky blue) in THF–water; yellow lines with red dots depicts dissolved surfactant molecules. (b) Initial stages of water droplet formation that are stabilized by surfactants. At this stage some polymer precipitation may also occur at the interface (depicted by the dark ring around the droplet). (c) Some droplet coalescence and continued formation of new water droplets leads to a slightly broad size distribution (coalescence and redistribution could be retarded due to the high solution viscosity). (d) Complete removal of THF followed by water generates the internally functionalized porous structures. e) IR spectral Image of the porous film. f) confocal fluorescence image of the porous film where the inner surface was functionalized with Rhodamine B. (For figures pl refer the pdf file)

In this project a qutrit tripod system is studied to implement quantum gates using non-Abelian geometric phases, allowing for holonomic quantum computation which in turn results in more robust computations. First, a general foundation of the theory is presented. This includes the relevant theory of matrices in Hilbert space, as well as theory of the quantum mechanics used in the report. The method is then described in depth, showing how the pulse area is fixed. Using properties of the Hamiltonian as well as the time-evolution operator of the tripod system the computational subspace can be derived. These findings are combined to show how the computational subspace evolves in time, resulting in the unitary matrix used to form quantum gates. Using educated guesses to find the necessary parameters or utilizing iterative methods to find the parameters are the two main approaches used for constructing the considered gates. Three of the suggested quantum gates are successfully implemented through educated guesses, namely X, T and Z using an angle parametrization of the phase and amplitude of the pulses. The last desired gate is the Hadamard-gate, but the implementation of said gate required numerical approximation. The reasons as to why this is the case, are later discussed.

Submitted by Maike Costa (maiksebas@gmail.com) on 2016-03-15T12:16:24Z No. of bitstreams: 1 arquivototal.pdf: 5169144 bytes, checksum: 66d534e3f0c0c59bf5d35a45290fa390 (MD5) / Made available in DSpace on 2016-03-15T12:16:24Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 5169144 bytes, checksum: 66d534e3f0c0c59bf5d35a45290fa390 (MD5) Previous issue date: 2015-02-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / In this thesis, we propose an experimental setup for the study of Landau quantization and associated effects in a two-dimensional ultracold atomic gas. Gauge fields can emerge in the equation of motion for the optically addressed ultracold atoms. To this end, spatially dependent dark states are necessary for the internal states of the atoms. A tripod level scheme yields two degenerate dark states which can leads to either an Abelian U(1) U(1) gauge field or a non-Abelian SU(2) gauge field. Using a suitable laser configuration, we obtain a uniform U(1) U(1) magnetic field which causes the atoms organize themselves in Landau levels. The strength of the effective magnetic field depends on the relative intensity of the lasers beams at the atomic cloud. We estimate the degeneracy of the energy levels for an atomic gas formed by atoms of 87Rb. In addition, we establish the experimental conditions to reach the lowest Landau level regime. In the zero-temperature limit, we realize the emergence of magnetic oscillations in the atomic energy and its derivative as function of the inverse of the effective magnetic field (de Haas van Alphen effect). The period of the de Haas van Alphen oscillation allow us to determine area of the Fermi circle for the atomic gas via an Onsager-like relation. We also show that detuning the a laser from the two-photon resonance we generate a parabolic scalar potential that laterally confines the atoms. As a consequence, the Landau levels degeneracy is removed, since the energy spectrum depends explicitly on the transverse atomic momentum. We show that the Landau levels presents a reminiscent degeneracy when the boundaries conditions are considered. The residual degeneracy occurs when different energy levels overlap. We map the residual degeneracy points as a function of the effective magnetic field. Finally, we present an experimental scheme for observing the spin Hall effect for ultracold atoms in a tripod configuration. / Nesta tese, propomos um arranjo experimental para o estudo da quantização de Landau e efeitos associados em um gás atômico ultrafrio bidimensional. Campos de calibre podem surgir na equação de movimento para átomos ultrafrios oticamente vestidos. Para que isto ocorra, estados escuros espacialmente dependentes são necessários a partir dos estados internos dos átomos. Átomos numa configuração de níveis de energia do tipo tripod produzem dois estados escuros degenerados, que podem levar a campos de calibre Abelianos U(1) U(1) ou não-Abelianos SU(2). Utilizando uma configuração adequada de lasers, mostramos que é possível se produzir um campo magnético sintético uniforme U(1) U(1) que atua nos átomos neutros fazendo-os se organizarem em níveis de Landau. A intensidade do campo efetivo depende da intensidade relativa dos feixes de luz na nuvem atômica. Estimamos a degenerescência dos níveis de energia para um gás atômico formado por átomos de 87Rb e estabelecemos as condições experimentais para que seja atingido o regime em que todos os átomos populam unicamente o nível de Landau menos energético. Considerando o limite de temperatura nula, verificamos o surgimento de oscilações magnéticas na energia e em sua derivada como uma função do inverso do campo magnético efetivo (efeito de Haas van Alphen). O período da oscilação magnética nos permite determinar a área do círculo de Fermi para o gás atômico através de uma expressão similar a de Onsager para sistemas eletrônicos. Mostramos também que dessintonizando um dos lasers em relação à ressonância de dois fótons geramos um potencial escalar parabólico que faz com os átomos sejam lateralmente confinados. Isto resulta na remoção da degenerescência dos níveis de Landau, uma vez que a energia depende explicitamente do momento atômico transverso. Demonstramos que, aplicando condições periódicas de contorno ao sistema, temos o surgimento de uma degenerescência residual. A degenerescência remanescente ocorre quando diferentes níveis de energia se superpõem. Mapeamos os pontos de degenerescência como uma função do campo magnético efetivo. Por fim, apresentamos um esquema experimental para a observação do efeito spin Hall para átomos ultrafrios em uma configuração tripod.

83 p. / Submitted by Santiago Fabio (fabio.ssantiago@hotmail.com) on 2012-12-19T19:35:24Z No. of bitstreams: 1 88.pdf: 1431314 bytes, checksum: e77a88c490348af714e77405775135f0 (MD5) / Made available in DSpace on 2012-12-19T19:35:24Z (GMT). No. of bitstreams: 1 88.pdf: 1431314 bytes, checksum: e77a88c490348af714e77405775135f0 (MD5) Previous issue date: 2011 / A relação simbiótica entre o Estado brasileiro e a Petrobras antecede a própria criação da empresa. Assim como o ano de 1997 marcou a quebra do monopólio estatal sobre as atividades da indústria em questão, o ano de 2003 representa a mudança drástica das atitudes do governo frente à maior empresa do país. Este relacionamento chegou a tal ponto que, recentemente, por ocasião das discussões sobre o novo marco regulatório da indústria do petróleo, representantes da Petrobras fizeram parte das discussões, junto com alguns ministérios e a ANP, que resultaram na proposta de alteração do modelo regulatório para o setor. Em vista do exposto, é de relevância científica conhecer a atuação da Petrobras na reforma do marco regulatório do Pré-sal, à luz das perspectivas da análise estratégica. Mais ainda, identificar se os resultados alcançados com o novo marco regulatório foram fruto de ação intencional da empresa ou apenas reações a provocações externas (atuação do Governo Federal, por exemplo). Com base nas considerações iniciais, o objetivo geral do trabalho foi analisar em que medida os fatores institucionais, os fatores internos (recursos da firma) ou os fatores ligados à indústria moldaram a participação da Petrobras no processo de elaboração da proposta de alteração do novo marco regulatório (Projetos de Lei n. 5.938 a 5.941, 2009). Pretendeu-se investigar, igualmente, quais desses fatores se sobressaíram nas mudanças e na readequação das regras do jogo. Este trabalho argumenta, fundamentado nos resultados, que a participação da Petrobras nos trabalhos de elaboração da proposta de mudança no marco regulatório do setor foi viabilizada pela confluência de fatores institucionais (IBV) e fatores internos à firma (RBV). O presente estudo mostrou-se como oportunidade de aprofundar os conhecimentos sobre o relacionamento entre a Petrobras e Governo, de identificar e melhor conhecer aspectos pontuais da experiência regulatória brasileira, assim como testar a aplicabilidade das perspectivas estratégicas na análise de situações concretas da realidade organizacional. / Salvador

Milking stools in the collections of the National Cultural History Museum: an investigation of typology. In this study the physical or other characteristics that might typify the traditional milking stool is investigated. This was done by studying a comparable group of eighteen examples from the Anthropology and Cultural History collections of the National Cultural History Museum in Pretoria. Six of the objects in the group studied had already been associated with the Afrikaans catchword ‘melkstoel’, hence the primary sources that informed the research included the museological data from the existing documentation of the Museum. The investigation confirmed that corresponding physical attributes, especially that pertaining to construction, could be identified in the group studied. It was also found that the objects had seen multiple, but indeterminable, functional applications. Since fifteen of the eighteen examples studied were essentially anonymous, as no documented provenance existed, their origin, history and meaning could not be established. The research was therefore extended to secondary sources, being textual descriptions and images, from which associations and correlations between the group studied and milking stools, especially from Western Europe and the English-speaking world, could be affirmed. Moreover, such links were also found to exist with other stools and certain vernacular chair typologies of shared approach, especially as to their construction. Findings identified certain typological features of the milking stool, but also a symbolic and metaphorical association. Multiple functions of and applications for the milking stool could be ascertained. AFRIKAANS : In hierdie studie word ondersoek ingestel of enige eienskappe, fisies of andersins, die tradisionele melkstoeltjie tipeer. Dit is onderneem aan die hand van ‘n studiegroep van agtien soortgelyke voorwerpe uit die Antropologie-versameling en die Kultuurhistoriese versameling van die Nasionale Kultuurhistoriese Museum, Pretoria. Dié primêre bronne word in die ondersoek ondersteun deur museale bronne ontsluit uit die Museum se dokumentasiesentrum, waar ses van die voorwerpe in die studiegroep reeds assosieer is met die trefwoord ‘melkstoel’. Die ondersoek het bevestig dat sekere fisiese kenmerke van die studiegroep, veral in hul konstruksie, dui op groepsverband. Daar is ook bevind dat die voorwerpe vir meervoudige, maar onbepaalde, funksies gebruik is.Van die agtien voorwerpe in die studiegroep is vyftien van anonieme herkoms, sodat hul oorsprong, geskiedenis en betekenis nie met sekerheid vasgestel kon word nie. Die navorsing is daarom uitgebrei na tekstuele beskrywings en beelde, as sekondêre bronne, om hierdie en ander kenmerke te ondersoek. Hieruit is die studiegroep in verband gebring met melkstoeltjies uit veral Wes-Europa en die Engelssprekende wêreld, asook ander stoeltjies en volkstoele wat soortgelyke eienskappe en konstruksiekenmerke het. Bevindings dui op bepaalde tipologiese kenmerke van ‘n melkstoeltjie, maar ook ‘n wyer, assosiatiewe begrip wat manifesteer in beeldspraak en ‘n metaforiese konteks. Meervoudige gebruike en aanwendings van die melkstoeltjie is nagespeur. Copyright / Dissertation (MInt)--University of Pretoria, 2010. / Architecture / unrestricted

This Master’s thesis deals with several variants construction design of camera crane. Two optimal variants are chosen with regard to practical usage. The thesis includes complete design of these variants with 3D models and strenght analyses. This analyses are processed by final element method. The first variant made based on technical documentation and it has worked for company Filmochod s.r.o..

Design of linear actuator for parallel kinematic structure is described in this master´s thesis. The parallel kinematic structure is described in the first part. Open kinematics structure and close kinematics structure are compared. Their benefits and disadvantages are also mentioned. Construction of some parallel robots is illustrated. Linear actuators of different company are described. Mechanical parameters and construction of linear actuator are compared. Design of linear actuator is described in practical part of master´s thesis. A few variation of linear actuator are introduced. Individual variants are evaluated by Multicriteria Decisional Analysis and a final conception is selected. Final conception of linear actuator is elaborated. Reasons for selection of every part of linear actuator are given and basic mechanical calculation design part is made. FEA analysis of the structural part of linear actuator is made. Design of linear actuator is evaluated in the final part.

Ce mémoire propose de faire l’analyse épistémologique du pouvoir créateur de la sélection naturelle. L’objectif sera de déterminer en quelle mesure il est légitime ou non de lui attribuer un tel pouvoir. Pour ce faire, il sera question de savoir si l’explication sélectionniste peut répondre à la question de l’origine des formes structurelles du vivant. Au premier chapitre, nous verrons le raisonnement qui mena Darwin à accorder un pouvoir créateur à la sélection naturelle. Nous comprendrons alors qu’un cadre exclusivement darwinien n’est peut-être pas à même de répondre au problème de la nouveauté évolutionnaire. Au deuxième chapitre, nous verrons dans une perspective darwinienne qu’il est possible de conserver l’essence de la théorie darwinienne et d’accorder à la sélection naturelle un pouvoir créateur, bien que deux des piliers darwiniens fondamentaux doivent être remis en question. Au troisième chapitre, nous verrons dans une perspective postdarwinienne que le pouvoir cumulatif de la sélection naturelle n’est peut-être pas à même d’expliquer l’adaptation sur le plan individuel, ce qui remet lourdement en question le pouvoir créateur de la sélection naturelle. Nous comprendrons alors que le débat, entre partisans d’une vision positive et partisans d’une vision négative de la sélection naturelle, dépend peut-être d’un présupposé métaphysique particulier. / This thesis proposes an epistemological analysis of the creative power of natural selection. The aim will be to determine to what extent it is legitimate or not to give to this selection such power. To do this, we will have to know if the selectionist explanation can answer the question of the origin of structural forms of life. In the first chapter, we will see the reasoning leading Darwin to give a creative power of natural selection. We will then understand that an exclusively Darwinian framework is maybe unable to address the problem of evolutionary novelty. In the second chapter, we will see in a Darwinian way that it is possible to retain the essence of Darwinian theory and to give natural selection a creative power, although two of the fundamental Darwinians pillars must be questioned. In the third chapter, we will see in a post-Darwinian way that the cumulative power of natural selection is maybe unable to explain adaptation at individual level, challenging seriously the creative power of natural selection. We will then understand that the debate, between supporters of a positive view and supporters of a negative view of natural selection, may depend on a particular metaphysical assumption.