From the perspective control practitioners, control of dynamics systems subjected to varying parameters is not a new topic. However systematic methods to accommodate such problems are relatively few and recent. This thesis addresses a subset of such problems falling under the nomenclature of Reconfigurable Control Systems in relation to flight control applications. A survey in the initial phase of research indicated a wide range of ad-hoc solutions with relatively brittle or non-existent theoretical guarantees towards to the stability of the entire system. Often the reconfigurable architecture consists of multiple conceptual components performing task of identifying system parameter changes, monitoring degradation in system performance and eventually finding some corrective action to regain lost performance. The change in system parameters if attributed to faults and damages to system, then the task of the control system is to achieve fault tolerance. Such fault tolerance is of high interest for flight control community since such a control system adaptation may lead to accommodation of real life faults during aircraft operation such as control surface damages, hydraulic actuation failures etc. The thesis work aims towards developing online control redesign methods capable of taking into account realistic requirements. The goals are 1) To find control input values in presence of faults. 2) Accommodate changes in performance criterion in presence of faults and, 3) Incorporate actuator limitations such as rate and position bounds. The research work is divided in three subparts. The initial phase consists of a study of existing solutions and methods capable of providing reconfigurable flight control architectures. This phase also covers some flight control literature relevant in the context of faults. Though the conclusions of this initial phase seem theoretically simple and straight forward, it is interesting to understand the amount of time and efforts invested by real world flight control practitioners to deduce these results. Essentially the work flow of this research work stems from practical requirement eventually leading to theoretical developments that can approximate the requirements often demanded by the people in field. The second phase consists of study and application of existing Model Predictive Control methods to the field of reconfigurable flight control. MPC has been successful in major complex control problems due to its online constrained optimisation methodology. Along-with certain theoretical extensions it is well capable of providing a successful means to redesign control action online in presence of failures. Simulation studies of sufficient fidelity and complexity on a full envelop fighter aircraft nonlinear model prove such control reconfiguration capabilities of MPC. Some new extensions of MPC have been developed to show it performing in a superior manner to conventional nominal formulations. The third phase of the research work focuses on further theoretical developments in the field robust adaptive control in MPC frame of operation. A new MPC formulation is derived which can accommodate constraints, uncertainty and constant disturbances (due to failed inputs). The novelty lies in the theoretical properties of this MPC as under certain conditions it is guaranteed to be asymptotically stable. This setup implements an optimization problem more complex than that of the nominal case. Typically, when disturbances and uncertainties are incorporated into the performance measure within MPC formulations, mini-max (worst-case) NP-hard problems can arise. The thesis contributes to the theory of robust synthesis by proposing a convex relaxation of a mini-max based MPC controller by adopting a Linear Matrix Inequality (LMI) optimisation formulation.

High-order accurate numerical simulations are performed to investigate the effects of wavy leading edges on aerofoil gust interaction (AGI) noise. The present study is based on periodic velocity dis-turbances predominantly in streamwise (x-) and vertical (y-) directions that are mainly responsible for the surface pressure fluctuation of an aerofoil. The perturbed velocity components of the present gust model do not vary in the spanwise (z-) direction. In general, the present results show that wavy leading edges lead to reduced AGI noise. Under the current incident gusts, it is found that the ratio of the wavy leading-edge peak-to-peak amplitude (LEA) to the longitudinal wavelength of the incident gust (λg) is the most important factor for the reduction of AGI noise. It is observed that AGI noise reduces with increasing LEA/λg, and significant noise reduction can be achieved for LEA/λg≥0.3. The present results also suggest that any two different cases with the same LEA/λg lead to a strong similarity in their profiles of noise reduction relative to the straight leading-edge case. The wavelength of wavy leading edges (LEW), however, shows minor influence on the reduction of AGI noise under the present gust profiles used. Nevertheless, the present results show that a meaningful improvement in noise reduction may be achieved when 1.06LEW/λg 61.5. In addition, it is found that the beneficial effects of wavy leading edges are maintained for various angles of attack and aerofoil thicknesses. Also, wavy leading edges remain effective in reducing AGI noise for gust profiles containing multiple frequency components. It is discovered in the current research that wavy leading edges result in in-coherent response time to the incident gust across the span, which causes a decreased level of surface pressure fluctuations, hence a reduced level of AGI noise.

A study was performed to investigate and optimize the application of perforated fairings for landing gear noise control. The sparse knowledge about this new subject has necessitated a more fundamental study involving a basic fairing-strut configuration, followed by wind tunnel tests on a simplified landing gear configuration incorporating perforated fairings. For the basic configuration, various exchangeable perforated half-cylindrical shells shrouding a circular cylinder were the subject of aerodynamic and acoustic tests. A qualitative and quantitative description has been given of the influence of perforated fairings on time averaged and unsteady flow and the related acoustics. The bled air through the shell prevents the formation of large scale vortices associated with the shell and thereby reduces low frequency noise. However, a test with a noisy H-beam replacing the circular cylinder has indicated that increasing porosity can result in adverse noise effects due to the bled mass flow washing the strut. Shearing flow past the perforate has been shown to create adverse self-noise of which both intensity and spectral content are dictated by the local velocity past the perforate. The application of perforated fairings to the simplified landing gear model reduces the low frequency noise introduced by the solid fairings to values below the baseline landing gear configuration in both side and ground view directions. Exposing the perforate outside the stagnation area does not yield extra noise reduction but introduces perforate self-noise. The synthesis of the conducted studies has shed new light on the application of perforated fairings for landing gear noise control. In particular the effects of porosity and perforation location have been clarified. However more research is needed for further optimization of these parameters.

O presente trabalho tem como objetivo principal o estudo da Termoluminescência (TL) e a Luminescência Opticamente Estimulada (LOE) de cristais de quartzo retirados de sedimentos localizados no litoral do Estado do Maranhão. Foi efetuada uma análise do comportamento da TL e da LOE do quartzo em relação à irradiação com radiação gama e beta, pré-aquecimentos e exposição à luz solar. Esta análise foi feita visando comparar os resultados obtidos por TL e LOE para aplicação na datação de cristais de quartzo. Os centros paramagnéticos da amostra foram analisados e identificados através de medidas de Ressonância Paramagnética Eletrônica (RPE), uma correlação dos centros de TL e LOE foi encontrada. Na datação por grão único observamos um comportamento inesperado, sendo um indício de que os centros responsáveis pela TL e a LOE não são os mesmos. As idades obtidas por LOE dependem apenas dos grãos que têm maior intensidade, por outro lado idades obtidas por TL resultam da contribuição de todos os grãos. As medidas de Difração de Raios-X (DRX), feitas no Laboratório Nacional de Luz Sincroton (LNLS), confirmaram que os grãos eram de quartzo apesar de apresentarem propriedades de emissão LOE diferentes, sugerindo que essas propriedades estão relacionadas às impurezas e defeitos pontuais intrínsecos de cada grão. Foram observados os sinais de RPE correspondentes ao quartzo e usando microondas com uma potência de 0,161 mW conseguiu-se isolar o sinal do centro E1 do quartzo. Observou-se que este centro cresce quando aquecido de 120 até 300 oC e para tratamentos acima de 300 oC até 450 oC ele decresce, podendo ser relacionado com os picos TL de altas temperaturas. As medidas de RPE, em baixa temperatura, mostraram a presença dos centros de Al. Foram encontradas Doses Anuais (DA) de 0,7 até 3,0 mGy/ano, e para alguns perfis os valores de DA foram mais constantes (Local B: 1,77-1,95 mGy/ano). As idades obtidas por LOE e TL (Protocolo Multiple Aliquot Regeneration: MAR) são bem próximas. Embora as obtidas por LOE, em geral, são um pouco menores do que as idades obtidas por TL. As profundidades estratigráficas dos sedimentos são diretamente proporcionais às idades obtidas. As três idades do segundo perfil estão dentro do Pleistoceno, já os outros perfis apresentam idades começando no Pleistoceno até o Holoceno. / The principal aim of the present work is to study the Thermoluminescence (TL) and Optically Stimulated Luminescence (OSL) of quartz crystals obtained from sediments located at coast of the state of Maranhão. The analysis using OSL and TL properties was carried out after gamma and beta irradiation, pre-heating, and exposure of samples to solar radiation, having in mind the dating of these sediments. EPR measurements were performed to investigate the possible paramagnetic centers in the sample, as well as establishing some correlation with the OSL and TL centers. Measurements of single grain dating showed an unexpected behavior. This result could be an evidence that the centers responsible for TL and OSL are not the same. Ages obtained by OSL depend only on the grain having greater intensity, on the other hand, ages obtained by TL depend on the contribution of multiple grains. The XRD measurements carried out at LNLS confirmed that all the separated grains were quartz grains, although different grains produced different OSL emission, suggesting that these properties are related to different intrinsic point defects and impurities in the grains. EPR signals were measured for quartz grains, using microwave power of 0.161 mW. It was able to isolate the signal of the E\'1-center. This signal is known to increase from 120 to 300 ºC and decreases by treatment beyond 300 ºC up to 450 ºC and may be related to the TL peaks at high temperatures. ESR measurements at 77 K showed the presence of Al centers. Annual Dose values were found to be between 0.7 to 3.0 mGy/year, and for some profiles the values were more constant (Location B: 1.77 to 1.95 mGy/year). The ages obtained by OSL and TL by MAR protocol are quite similar, although those obtained by OSL usually are somewhat smaller than the ages obtained by TL. The stratigraphic depths of sediments are directly proportional to the ages obtained. The three ages of the second profile are within the Pleistocene, since the other profiles show ages starting in the Late Pleistocene to Holocene.

A forma isomórfica predominante nos biominerais (casca de ostra, coral, madrepérola e concha) estudados foi a aragonita. Contudo, o surgimento da fase calcita deu-se à temperatura de 500°C a uma taxa de aquecimento de 10°C/s para todas as amostras; e para a amostra de coral, à temperatura de 400°C, independente da taxa de aquecimento. O elemento mais abundante nas amostras de biominerais foi o Ca na forma de CaO e para os silicatos (tremolita, diopsídio e rodonita), o Si na forma de SiO. O elemento traço mais presente nas amostras de biominerais foi o Fe. A análise de ressonância paramagnética eletrônica mostrou as linhas de Mn2+ nas amostras de coral e madrepérola, antes da irradiação. Para amostras irradiadas, os defeitos encontrados foram os radicais CO2-, CO33-, CO3-, SO2-, SO3-, e num intervalo de g entre 2,0010 e 2,0062. Na análise por absorção óptica dos biominerais foram encontradas transições devido à presença de Mn nas amostras. Foi observado um pico termoluminescente (TL) em aproximadamente 140°C para os biominerais e em 180°C para os silicatos, cuja intensidade depende diretamente da dose. Para amostras expostas a diferentes tipos de radiações, o pico TL ocorre em temperaturas mais baixas. Para as curvas dose-resposta obtidas para esses materiais, foi possível determinar um intervalo de linearidade para o qual a sua aplicação em dosimetria de doses altas se torna possível. Levando-se em consideração o tipo de radiação, dentre os biominerais e os silicatos, obteve-se a menor dose detectável (40mGy), para a radiação gama em amostra de casca de ostra utilizando-se a técnica de medição de luminescência opticamente estimulada (LOE). Para radiação beta, as amostras de tremolita e diopsídio obtiveram a menor dose detectável (60mGy). No geral, obteve-se uma boa reprodutibilidade para as amostras, utilizando-se as técnicas TL, LOE e emissão exoeletrônica termicamente estimulada (TSEE) para as radiações alfa, beta e gama. Portanto, pode-se concluir que as amostras caracterizadas neste trabalho podem ser utilizadas como detectores/dosímetros de doses altas. / The predominant isomorphous form in the biominerals studied in this work (oyster shell, coral, mother of pearl and shell) was aragonite. The appearence of the calcite phase occurred at 500°C at a heating rate of 10°C/s for all samples except for the coral sample, which was 400°C, independent of the heating rate. The most abundant element in the biominerals samples was Ca in the CaO form, and in the silicates (tremolite, diopside and rhodonite) Si in the SiO form. The most common trace element observed in the biominerals samples was Fe. The analyses of electron paramagnetic resonance showed lines of Mn2+ in the coral and mother-of-pearl samples before irradiation. In the case of the irradiated samples, the defects found were CO2-, CO33-, CO3- and SO2-, in the g range between 2.0010 and 2.0062. In the analyses by optical absorption of biominerals, transitions due to the presence of Mn in the samples were found. A thermoluminescent (TL) peak at approximately 140°C was found for the biominerals and at 180°C for silicates, which intensity depends directly on the dose. For samples exposed to different types of radiation, the TL peak occurred at lower temperatures. From the dose-response curves obtained for these materials, it was possible to determine a linear range for which their application in high dose dosimetry becomes possible. Taking into account the radiation type, among biominerals and silicates, the lowest detectable dose (40mGy) to gamma radiation was achieved for oyster shell samples using the measuring technique of optically stimulated luminescence (OSL). Using beta radiation, for diopside and tremolite samples the lowest detectable dose of 60mGy was obtained. For all samples, using the TL, OSL and thermally stimulated exoelectron emission (TSEE) techniques in alpha, beta and gamma radiation beans a good response reproducibility was obtained. Therefore, the samples characterized in this work are suitable to be used as high dose detectors/dosimeters.

A forma isomórfica predominante nos biominerais (casca de ostra, coral, madrepérola e concha) estudados foi a aragonita. Contudo, o surgimento da fase calcita deu-se à temperatura de 500°C a uma taxa de aquecimento de 10°C/s para todas as amostras; e para a amostra de coral, à temperatura de 400°C, independente da taxa de aquecimento. O elemento mais abundante nas amostras de biominerais foi o Ca na forma de CaO e para os silicatos (tremolita, diopsídio e rodonita), o Si na forma de SiO. O elemento traço mais presente nas amostras de biominerais foi o Fe. A análise de ressonância paramagnética eletrônica mostrou as linhas de Mn2+ nas amostras de coral e madrepérola, antes da irradiação. Para amostras irradiadas, os defeitos encontrados foram os radicais CO2-, CO33-, CO3-, SO2-, SO3-, e num intervalo de g entre 2,0010 e 2,0062. Na análise por absorção óptica dos biominerais foram encontradas transições devido à presença de Mn nas amostras. Foi observado um pico termoluminescente (TL) em aproximadamente 140°C para os biominerais e em 180°C para os silicatos, cuja intensidade depende diretamente da dose. Para amostras expostas a diferentes tipos de radiações, o pico TL ocorre em temperaturas mais baixas. Para as curvas dose-resposta obtidas para esses materiais, foi possível determinar um intervalo de linearidade para o qual a sua aplicação em dosimetria de doses altas se torna possível. Levando-se em consideração o tipo de radiação, dentre os biominerais e os silicatos, obteve-se a menor dose detectável (40mGy), para a radiação gama em amostra de casca de ostra utilizando-se a técnica de medição de luminescência opticamente estimulada (LOE). Para radiação beta, as amostras de tremolita e diopsídio obtiveram a menor dose detectável (60mGy). No geral, obteve-se uma boa reprodutibilidade para as amostras, utilizando-se as técnicas TL, LOE e emissão exoeletrônica termicamente estimulada (TSEE) para as radiações alfa, beta e gama. Portanto, pode-se concluir que as amostras caracterizadas neste trabalho podem ser utilizadas como detectores/dosímetros de doses altas. / The predominant isomorphous form in the biominerals studied in this work (oyster shell, coral, mother of pearl and shell) was aragonite. The appearence of the calcite phase occurred at 500°C at a heating rate of 10°C/s for all samples except for the coral sample, which was 400°C, independent of the heating rate. The most abundant element in the biominerals samples was Ca in the CaO form, and in the silicates (tremolite, diopside and rhodonite) Si in the SiO form. The most common trace element observed in the biominerals samples was Fe. The analyses of electron paramagnetic resonance showed lines of Mn2+ in the coral and mother-of-pearl samples before irradiation. In the case of the irradiated samples, the defects found were CO2-, CO33-, CO3- and SO2-, in the g range between 2.0010 and 2.0062. In the analyses by optical absorption of biominerals, transitions due to the presence of Mn in the samples were found. A thermoluminescent (TL) peak at approximately 140°C was found for the biominerals and at 180°C for silicates, which intensity depends directly on the dose. For samples exposed to different types of radiation, the TL peak occurred at lower temperatures. From the dose-response curves obtained for these materials, it was possible to determine a linear range for which their application in high dose dosimetry becomes possible. Taking into account the radiation type, among biominerals and silicates, the lowest detectable dose (40mGy) to gamma radiation was achieved for oyster shell samples using the measuring technique of optically stimulated luminescence (OSL). Using beta radiation, for diopside and tremolite samples the lowest detectable dose of 60mGy was obtained. For all samples, using the TL, OSL and thermally stimulated exoelectron emission (TSEE) techniques in alpha, beta and gamma radiation beans a good response reproducibility was obtained. Therefore, the samples characterized in this work are suitable to be used as high dose detectors/dosimeters.

O problema da dosimetria beta está ligado a indivíduos que manipulam fontes radioativas a pequenas distâncias ou em contato. O objetivo principal da dosimetria beta é a determinação da dose na pele e no cristalino do olho. A câmara de extrapolação Böhm foi caracterizada em feixes de radiação beta das fontes de 85Kr e 147Pm e ela foi estabelecida como sistema de padronização primária. Foram determinadas as taxas de dose absorvida no ar e no tecido à profundidade nula e de 0,07 mm das fontes de 85Kr e 147Pm e os seus fatores de transmissão. Além disso, foi caracterizado e estabelecido um sistema de transferência ou método alternativo/complementar de dosimetria beta. Foram aplicadas as técnicas de termoluminescência e de luminescência opticamente estimulada, para a caracterização de detectores de SOL-GEL α-Al2O3 em campos padrões de radiação beta, e foram determinados os parâmetros cinéticos do processo termoluminiscente. O material estudado mostrou-se adequado para a dosimetria beta. Foi estabelecido um modelo computacional pelo método Monte Carlo para a câmara de extrapolação e para as fontes de radiação; foram determinadas as taxas de dose absorvida, os fatores de correção de Bremsstrahlung, os fatores de correção pelo retroespalhamento do eletrodo coletor e do anel de guarda da câmara de extrapolação e os fatores de dependência angular. Para o sistema de transferência de dosimetria beta, foram determinados os fatores de correção pela atenuação no ar e o espalhamento da radiação no suporte de irradiação dos detectores pelo método Monte Carlo. Todas os testes de caracterização, assim como o modelo de Monte Carlo, foram também realizados e implementados com a fonte de 90Sr/90Y por ser a fonte de referência da radiação beta e para fins comparativos. / The problem of beta dosimetry is linked to individuals who manipulate radioactive sources at small distances or in contact. The main objective of beta dosimetry is to determine the dose on the skin and in the lens of the eye. The Böhm extrapolation chamber was characterized in beta radiation beams from 85Kr and 147Pm sources, and a primary standard system was established. The absorbed dose rates in air and tissue at null depth and at 0.07 mm for 85Kr and 147Pm sources and the transmission factors were determined. In addition, a transfer system or alternative/complementary beta dosimetry method was characterized and established too. The thermoluminescence and optically stimulated luminescence techniques were applied for the characterization of the SOL-GEL α-Al2O3 detectors in standard beta radiation fields, and the kinetic parameters of the thermoluminescent process were determined. The studied material was shown to be suitable for beta dosimetry. A model by the Monte Carlo method for the extrapolation chamber and the radiation sources was established. The absorbed dose rates, the Bremsstrahlung correction factors, the correction factors for the backscattering of the collecting electrode and the guard ring of the extrapolation chamber, and the angular dependence factors were determined. For the beta dosimetry transfer system, the correction factors by attenuation in air and the scattering of the radiation in the irradiation holder of the detectors were determined by the Monte Carlo method. All the characterization and tests, as well as the Monte Carlo model, were performed and implemented with the 90Sr/90Y source, because it is the reference source for beta radiation and for comparative purposes.

Darbo tikslas – ištirti rapsų aliejaus peresterinimo procesą naudojant biobutanolį, įvertinti gauto biodyzelino savybes ir poveikį aplinkai. Darbo objektas – rapsų aliejaus riebalų rūgščių butilesteriai, gauti po rapsų aliejaus peresterinimo biobutanoliu. Darbo metodai – rapsų aliejaus peresterinimas butanoliu atliktas biotechnologiniu metodu, naudojant biokatalizatorių Lipozyme TL IM. Peresterinimo laipsnis, butilesterių ir parcialinių gliceridų kiekis nustatyti plonasluoksnės ir dujų chromatografijos metodais. Gauto biodyzelino savybės įvertintos pagal standarte LST EN 14214 pateiktas metodikas. Variklio eksploataciniai ir deginių emisijų tyrimai VGT universitete atlikti 1992 m. gamybos ,,Audi-80‘‘ automobilio dyzeliniu varikliu. Variklio išmetamųjų dujų analizei naudotas išmetamųjų dujų analizatorius AVL DiCom 4000. Biologinis degalų suirimas atliktas taikant OECD 301 F ,,Manometrinės respirometrijos‘‘ metodą AL 606 prietaisu. Darbo rezultatai. Nustatytos optimalios 2 stadijų rapsų aliejaus peresterinimo butanoliu proceso sąlygos. Pagaminti rapsų aliejaus riebalų rūgščių butilesteriai (RBE) atitinka standarto LST EN 14214 reikalavimus. Grynų butilesterių atsparumą oksidacijai daugiau kaip 6 val. padidina antioksidantas – IONOL BF 200 (2000 ppm). Vasaros ir pereinamuoju laikotarpiu gryni butilesteriai ir jų mišiniai su žieminiu dyzelinu ir butanoliu tinkami naudoti be specialių priedų. Maišant rapsų aliejaus riebalų rūgščių butilesterius su žieminiu dyzelinu ir butanoliu... [toliau žr. visą tekstą] / Aim of the work – to analyze the process of rapeseed oil transesterification by using biobutanol, to evaluate the characteristics of the derived biodiesel and its impact on the environment. Object of research – butyl esters of rapeseed oil received after the transesterification of rapeseed oil using biobutanol. Research methods – transesterification of rapeseed oil using biobutanol has been performed by applying biotechnological method, using biocatalyst Lipozyme TL IM. The level of transesterification and quantity of butyl esters and partial glycerides has been determined by methods of thin-layer and gas chromatography. The characteristics of the derived biodiesel have been evaluated according to the methodology provided by standard LST EN 14214. The analysis of engine exploitation and environmental characteristics have been performed at VGT university on the diesel engine of 1992 “Audi-80”. For the analysis of exhaust gases of engine the gas analyzer AVL DiCom 4000 has been used. Degradation of biological fuel has been performed according to OECD 301 F “Manometric respirometry” using AL 606 device. Results of research. Optimal conditions of 2-stage rapeseed oil transesterification process using butanol. Were determined the produced butyl esters of rapeseed oil meet the requirements of LST EN 14214 standards. Antioxidant JONOL BF 200 increases the oxidative stability of pure butyl esters. In summer or during transition period pure butyl esters and their mixtures with... [to full text]

O presente trabalho tem como objetivo principal o estudo da Termoluminescência (TL) e a Luminescência Opticamente Estimulada (LOE) de cristais de quartzo retirados de sedimentos localizados no litoral do Estado do Maranhão. Foi efetuada uma análise do comportamento da TL e da LOE do quartzo em relação à irradiação com radiação gama e beta, pré-aquecimentos e exposição à luz solar. Esta análise foi feita visando comparar os resultados obtidos por TL e LOE para aplicação na datação de cristais de quartzo. Os centros paramagnéticos da amostra foram analisados e identificados através de medidas de Ressonância Paramagnética Eletrônica (RPE), uma correlação dos centros de TL e LOE foi encontrada. Na datação por grão único observamos um comportamento inesperado, sendo um indício de que os centros responsáveis pela TL e a LOE não são os mesmos. As idades obtidas por LOE dependem apenas dos grãos que têm maior intensidade, por outro lado idades obtidas por TL resultam da contribuição de todos os grãos. As medidas de Difração de Raios-X (DRX), feitas no Laboratório Nacional de Luz Sincroton (LNLS), confirmaram que os grãos eram de quartzo apesar de apresentarem propriedades de emissão LOE diferentes, sugerindo que essas propriedades estão relacionadas às impurezas e defeitos pontuais intrínsecos de cada grão. Foram observados os sinais de RPE correspondentes ao quartzo e usando microondas com uma potência de 0,161 mW conseguiu-se isolar o sinal do centro E1 do quartzo. Observou-se que este centro cresce quando aquecido de 120 até 300 oC e para tratamentos acima de 300 oC até 450 oC ele decresce, podendo ser relacionado com os picos TL de altas temperaturas. As medidas de RPE, em baixa temperatura, mostraram a presença dos centros de Al. Foram encontradas Doses Anuais (DA) de 0,7 até 3,0 mGy/ano, e para alguns perfis os valores de DA foram mais constantes (Local B: 1,77-1,95 mGy/ano). As idades obtidas por LOE e TL (Protocolo Multiple Aliquot Regeneration: MAR) são bem próximas. Embora as obtidas por LOE, em geral, são um pouco menores do que as idades obtidas por TL. As profundidades estratigráficas dos sedimentos são diretamente proporcionais às idades obtidas. As três idades do segundo perfil estão dentro do Pleistoceno, já os outros perfis apresentam idades começando no Pleistoceno até o Holoceno. / The principal aim of the present work is to study the Thermoluminescence (TL) and Optically Stimulated Luminescence (OSL) of quartz crystals obtained from sediments located at coast of the state of Maranhão. The analysis using OSL and TL properties was carried out after gamma and beta irradiation, pre-heating, and exposure of samples to solar radiation, having in mind the dating of these sediments. EPR measurements were performed to investigate the possible paramagnetic centers in the sample, as well as establishing some correlation with the OSL and TL centers. Measurements of single grain dating showed an unexpected behavior. This result could be an evidence that the centers responsible for TL and OSL are not the same. Ages obtained by OSL depend only on the grain having greater intensity, on the other hand, ages obtained by TL depend on the contribution of multiple grains. The XRD measurements carried out at LNLS confirmed that all the separated grains were quartz grains, although different grains produced different OSL emission, suggesting that these properties are related to different intrinsic point defects and impurities in the grains. EPR signals were measured for quartz grains, using microwave power of 0.161 mW. It was able to isolate the signal of the E\'1-center. This signal is known to increase from 120 to 300 ºC and decreases by treatment beyond 300 ºC up to 450 ºC and may be related to the TL peaks at high temperatures. ESR measurements at 77 K showed the presence of Al centers. Annual Dose values were found to be between 0.7 to 3.0 mGy/year, and for some profiles the values were more constant (Location B: 1.77 to 1.95 mGy/year). The ages obtained by OSL and TL by MAR protocol are quite similar, although those obtained by OSL usually are somewhat smaller than the ages obtained by TL. The stratigraphic depths of sediments are directly proportional to the ages obtained. The three ages of the second profile are within the Pleistocene, since the other profiles show ages starting in the Late Pleistocene to Holocene.

The thesis is a historical study of the first twenty years of the British motor cycle industry in terms of the development of its product. The main theoretical issue is standardization, not in its usual sense as a forma l activity aimed at the setting up of standards, but as a trend the effect of which is for products to become more and more alike across the industry as a whole. Standardization in this sense is to a large extent an unintended consequence of the wish on the part of producers to design products which operate more efficiently, which can be produced more cheaply, and which have the widest possible appeal in the marketplace; and of the preference, on the part of the majority of consumers, for products which are familiar and of known reputation and performance, as against those which are new and untried. The trend to standardization is analysed into its main components , functional efficiency, production efficiency, and marketing efficiency, and these are used as the basis of a number of propositions which make it possible to consider in more depth the development of the product during the three phases of industry development : experimental, developmental, and standardization . The more substantive chapters of the thesis are organized around three main themes, the development of the industry as a whole, and the development of the product from a technical point of view, and from a consumer point of view. The main conclusion is that the development of its product into a standard form--one on which newcomers to the industry can base their own products and which consumers can recognise as reliable and worthy of purchase-is the most critical stage in the development and consolidation of a new industry.