Submitted by Irene Nascimento (irene.kessia@ufpe.br) on 2016-07-12T19:37:30Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese_FlaviaPortela_2015.pdf: 24722134 bytes, checksum: ecaec07cae254145230ae32ad7de71e3 (MD5) / Made available in DSpace on 2016-07-12T19:37:30Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese_FlaviaPortela_2015.pdf: 24722134 bytes, checksum: ecaec07cae254145230ae32ad7de71e3 (MD5) Previous issue date: 2015-03-26 / CAPES / O estudo em sistemas de multicamadas supercondutoras alcan cou grande interesse na pesquisa de novos materiais, pois al em de apresentarem ampla aplicabilidade tecnol ogica, oferecem fascinantes possibilidades de observar novos fen^omenos na supercondutividade. Esta ultima caracter stica e a de maior motiva c~ao para esta tese, uma vez que pouco ainda se tem reportado a respeito da supercondutividade em multicamadas constitu das por supercondutor(S)/supercondutor(S0). Neste trabalho, estudamos tr^es novos sistemas nanoestruturados formados por supercondutores elementares, de baixa temperatura cr tica, tais como ni obio (Nb), chumbo (Pb) e estanho (Sn), a saber, a tricamada Nb(5)/Pb(500)/Nb(50) e as multicamadas Nb(100)/[Sn(50)/Nb(50)]7 e Cr(10)/Nb(100)/[Sn(50)/Nb(50)]7, onde o termo entre par^enteses indica a espessura da referida camada em nan^ometros e os colchetes indicam que a estrutura Nb/Sn e repetida 7 vezes. Para compara c~ao, tamb em s~ao analisados lmes de refer^encia de Nb, Pb e Sn. Os lmes e as multicamadas foram crescidos a temperatura ambiente por deposi c~ao via sputtering, utilizando fontes DC e RF. As amostras foram caracterizadas por difra c~ao de raios X de baixo ^angulo, microscopia eletr^onica de varredura e por microscopia de for ca at^omica. As propriedades supercondutoras foram estudadas atrav es de medidas magn eticas e de transporte el etrico. Magnetiza c~ao e resistividade foram medidas como fun c~oes da temperatura e do campo magn etico aplicado perpendicular e paralelamente as camadas. Os tr^es sistemas apresentaram transi c~oes supercondutoras abruptas, tanto na magnetiza c~ao quanto na resistividade em fun c~ao da temperatura, com os valores de TC obtidos de 7,2 K para o Nb/Pb/Nb, 5,2 K para o Nb/[Sn/Nb]7 e 3,7 K para o Cr/Nb/[Sn/Nb]7. As propriedades supercondutoras dos lmes de Pb, Nb e Sn, tais como TC, 0Hc2 e comprimentos caracter sticos apresentaram coer^encia com os valores reportados na literatura, con rmando a boa qualidade das camadas. Flux jumps s~ao observados nos loops de histerese em todos os sistemas, os quais s~ao atribu dos a instabilidades termomagn eticas. A amostra Nb/Pb/Nb apresentou uma curvatura positiva na depend^encia de 0Hc2(T), indicando que a supercondutividade ocorre preferencialmente na camada de Pb para T > T e preferencialmente na camada de Nb para T < T , de acordo com a teoria de Takahashi-Tachiki. Os comprimentos caracter sticos s~ao calculados, classi cando as multicamadas como supercondutores do tipo II. Veri camos grande in u^encia do material magn etico Cr na supercondutividade da multicamada, causando a diminui c~ao da temperatura cr tica do sistema e modi cando o comportamento dos campos cr ticos inferior e superior. A depend^encia de 0Hc1(T), em todos os sistemas, revelou um comportamento n~ao convencional, que e atribu do a uma manifesta c~ao de sistemas multicomponentes com componentes espacialmente separadas. / The study of superconducting multilayers systems has achieved much interest in the research of new materials. Besides their wide technological applicability, these structures o er fascinating possibilities to observe new phenomena in superconductivity. The latter characteristic is the fundamental motivation for this thesis, since a little has been reported about multilayers constituted of superconductor(S)/superconductor(S0). In this work, we have studied three new nanostructured systems formed by low critical temperature conventional superconductors, such as niobium (Nb), lead (Pb) and tin (Sn): the trilayer Nb(5)/Pb(500)/Nb(50) and the multilayers Nb(100)/[Sn(50)/Nb(50)]7 and Cr(10)/Nb(100)/[Sn(50)/Nb(50)]7. The term in parenthesis indicates the thickness of the layer in nanometers and the brackets that Nb/Sn structure is repeated 7 times. For comparison, the reference lms of Nb, Pb and Sn were also analyzed. The thin lms and multilayers were growth at room temperature via sputtering deposition, by using DC and RF sources. The samples were characterized for small angle X ray di raction, scanning electron microscopy (SEM), and atomic force microscopy (AFM). The superconducting properties were investigated through magnetic and electric transport measurements. The magnetization and resistivity were obtained as functions of temperature and magnetic eld applied both perpendicularly and parallel to the layers. All the multilayers systems have showed sharp superconducting transitions in the dependence of magnetization and resistivity with the temperature. The multilayers critical temperatures were found to be 7.2 K for Nb/Pb/Nb, 5.2 K for Nb/[Sn/Nb]7 and 3.7 K for Cr/Nb/[Sn/Nb]7. The superconducting properties of reference lms Pb, Nb and Sn, such as critical temperature, upper critical eld and characteristic lengths were consistent with the literature values, con rming the good quality of the samples. In the three systems ux jumps were observed, which are attributed to thermomagnetic instabilities. The Ginzburg-Landau parameter is estimated, classifying the multilayers as type II superconductors. In the case of Nb/Pb/Nb sample, it presented an upward curvature in the 0Hc2(T) diagrams, which is a signature of superconductivity nucleation in the each layer, in accordance with Takahashi-Tachiki theory for multilayered systems. We found out a noticeable in uence of the magnetic material Cr on the multilayer superconducting properties, reducing the critical temperature of the system and modifying the lower and upper critical elds behavior. The dependence of 0Hc1(T), of all the multilayers, revealed a non-conventional behavior feature, which is consistent with a multicomponent behavior with spatially separated components.

(in English): Electroconvulsive therapy (ECT) is a very effective treatment procedure for patients with severe and treatment resistant psychiatric disorders. This Thesis deals with the impact of electroconvulsive therapy on cognitive function, specified as a measurement of cognitive function after electroconvulsive therapy, focusing on the monitoring of cognitive function, eventually their deficits with the passage of time after ECT. At several time points (T1 week after ECT completion; T2: 6-8 weeks after ECT completion) from ECT completion the progression of cognitive performance of patients was repeatedly measured. Respondents were divided according to their diagnosis (mood disorders groop and schizophrenia group). The groups were compared with each other. The aim of the Thesis is the observance of the cognitive changes in patients over time after electroconvulsive therapy. In the final stage 18 subjects were submissed into the study (10 women and 8 men). In terms of diagnosis 39% were diagnosed with the disease in the ICD category F20-F29; 33% were diagnosed with mood disorders (category ICD: F30-F39) and 28% were diagnosed with F06.3 organic affective disorder. The MCCB (MATRICS Consensus Cognitive Battery) was chosen as a method for data scan, it has very good psychometric properties also...

Please read the abstract in the dissertation. Copyright / Dissertation (MEng)--University of Pretoria, 2010. / Chemical Engineering / unrestricted

This PhD work is dedicated to investigating the fringe effect of electrical capacitance tomography (ECT) and electrical resistance tomography (ERT) sensors systematically, exploring possible solutions and developing a novel 3D imaging technique by utilising the fringe effect of electrical tomography (ET) sensors. By referring to 2D simulation results, the fringe effect is investigated for 3D ERT and ECT sensor models with or without grounded guards, and with different axial lengths of electrodes. Simulation results reveal that increasing the electrode length or adopting grounded guards can reduce the fringe effect of ECT and ERT sensors. In this work, a voltage-excitation strategy is proposed and validated for ERT sensors instead of the conventional current-injection strategy. This approach enables ECT and ERT sensors to be integrated together as a common one to simplify the sensor design and reduce the interference between the ECT and ERT dual-modality measurements. For a conventional ERT sensor with the adjacent strategy, the fringe effect is evaluated for axially non-uniform central core and off-central core distributions at different axial positions and with different axial dimensions and conductivity contrasts. A method is proposed for compensating the fringe effect with the above typical distributions and a two-object distribution. A three-plane ERT sensor scheme is suggested for reducing the fringe effect induced by objects outside the sensor plane and the over-estimation by Landweber iteration. Both simulation and experiment have proved the effectiveness of the three-plane sensor scheme and the compensation method. Using the fringe effect, a novel 3D imaging method is proposed for ET with a single-plane sensor. It is explored to image metallic objects with ECT. The axial position of the object is derived by examining the corresponding fringe effect in a single-plane ECT sensor. Along with 2D imaging of the cross-sectional distribution, 3D imaging is achieved for a cylindrical metallic rod with known size. With this method, only the 3D position of the object needs to be calculated during the reconstruction which reduces the number of unknowns greatly and can improve the accuracy and stability of reconstruction.

Electroconvulsive therapy (ECT) effectively treats depression by administration of repeated seizure-inducing electrical stimuli. Sprague-Dawley rats were administered 6 electroconvulsive shocks (ECS) over 2 weeks, and in vivo single unit extracellular electrophysiological activity was recorded after 48 hours. Overall firing activity in the locus coeruleus and ventral tegmental area was unchanged, suggesting the therapeutic efficacy of ECT may not be attributed to increased norepinephrine and dopamine release. There were more spontaneously active neurons in the substantia nigra pars compacta (SNc), indicating greater dopamine tone in the nigrostriatal motor pathway, which may contribute to alleviation of psychomotor retardation. In the facial motor nucleus (FMN), locally administered norepinephrine, but not serotonin, facilitated greater glutamate-induced firing, which may contribute to improved facial motricity. Current results indicate that repeated ECS enhances postsynaptic norepinephrine neurotransmission in the FMN and SNc dopamine neurotransmission, which could represent the mechanism behind the alleviation of depressive symptoms including psychomotor retardation.

As part of the production of certain solid-dosage pharmaceuticals, granulated ingredients are dried in a batch fluidized bed dryer. Currently, the determination of the completion of the drying process is accomplished through measurements of product or outlet air temperatures. No quantitative measurement of hydrodynamic behaviour is employed. Changes in bed hydrodynamics caused by variations in fluidization velocity may lead to increased particle attrition. In addition, excessive desiccation of the granules caused by inaccurate determination of the drying endpoint may lead to an increase in the thermal and mechanical stresses within the granules. The activity of future high-potency or peptide based drug products may be influenced by these effects. Therefore, the quantification of hydrodynamic changes may be a key factor in the tighter control of both fluidization velocity and product moisture, which are critical for maintaining product quality. <p>High-frequency measurements of pressure fluctuations in a batch fluidized bed dryer containing pharmaceutical granulate have been used to provide a global, non-intrusive indication of the hydrodynamic changes occurring throughout the drying process. A chaotic attractor comparison statistical test known as the S-statistic, has been applied to quantify these changes in drying and a related unit operation, fluidized bed granulation. The S-statistic showed a sensitivity to moisture which is not seen with frequency and amplitude analysis. In addition, the S-statistic has been shown to be useful in identifying an undesirable bed state associated with the onset of entrainment in a bed instrumented for the collection of both pressure fluctuation and entrainment data. Thus, the use of the S-statistic analysis of pressure fluctuations may be utilized as a low-cost method for determining product moisture or changes hydrodynamic state during fluidized bed drying. <p>Electrical capacitance tomography (ECT) has also been applied in this study to image the flow structure within a batch fluidized bed used for the drying of pharmaceutical granulate. This represents the first time that ECT has been applied to a bed of wet granulate material. This was accomplished through the use of a novel dynamic correction technique which accounts for the significant reduction in electrical permittivity occurring as moisture is lost during the drying process. The correction has been independently verified using x-ray tomography. <p>Investigation of the ECT images taken in the drying bed indicates centralized bubbling behaviour for approximately the first 5 minutes of drying. This behaviour is a result of the high liquid loading of the particles at high moisture. Between moisture contents of 18-wt% and 10-wt%, the tomograms show an annular pattern of bubbling behaviour with a gradual decrease in the cross-sectional area involved in bubbling behaviour. The dynamic analysis of this voidage data with the S-statistic showed that a statistically significant change occurs during this period near the walls of the vessel, while the centre exhibits less variation in dynamic behaviour. The changes identified by the S-statistic analysis of voidage fluctuations near the wall were similar to those seen in the pressure fluctuation measurements. This indicates that the source of the changes identified by both these measurement techniques is a result of the reduction in the fraction of the bed cross-section involved in bubbling behaviour. At bed moisture contents below 5-wt%, rapid divergence was seen in the S-statistic applied to both ECT and pressure fluctuation measurements. This indicates that a rapid change in dynamics occurs near the end of the drying process. This is possibly caused by the entrainment of fines at this time, or the build-up of electrostatic charge. <p>The use of the complimentary pressure fluctuation and ECT measurement techniques have identified changes occurring as a result of the reduction of moisture during the drying process. Both the localized changes in the voidage fluctuations provided by the ECT imaging and the global changes shown by the pressure fluctuation measurements indicate significant changes in the dynamic behaviour caused by the reduction of moisture during the drying process. These measurement techniques could be utilized to provide an on-line indication of changes in hydrodynamic regime. This information may be invaluable for the future optimization of the batch drying process and accurate determination of the drying endpoint.

As part of the production of certain solid-dosage pharmaceuticals, granulated ingredients are dried in a batch fluidized bed dryer. Currently, the determination of the completion of the drying process is accomplished through measurements of product or outlet air temperatures. No quantitative measurement of hydrodynamic behaviour is employed. Changes in bed hydrodynamics caused by variations in fluidization velocity may lead to increased particle attrition. In addition, excessive desiccation of the granules caused by inaccurate determination of the drying endpoint may lead to an increase in the thermal and mechanical stresses within the granules. The activity of future high-potency or peptide based drug products may be influenced by these effects. Therefore, the quantification of hydrodynamic changes may be a key factor in the tighter control of both fluidization velocity and product moisture, which are critical for maintaining product quality. <p>High-frequency measurements of pressure fluctuations in a batch fluidized bed dryer containing pharmaceutical granulate have been used to provide a global, non-intrusive indication of the hydrodynamic changes occurring throughout the drying process. A chaotic attractor comparison statistical test known as the S-statistic, has been applied to quantify these changes in drying and a related unit operation, fluidized bed granulation. The S-statistic showed a sensitivity to moisture which is not seen with frequency and amplitude analysis. In addition, the S-statistic has been shown to be useful in identifying an undesirable bed state associated with the onset of entrainment in a bed instrumented for the collection of both pressure fluctuation and entrainment data. Thus, the use of the S-statistic analysis of pressure fluctuations may be utilized as a low-cost method for determining product moisture or changes hydrodynamic state during fluidized bed drying. <p>Electrical capacitance tomography (ECT) has also been applied in this study to image the flow structure within a batch fluidized bed used for the drying of pharmaceutical granulate. This represents the first time that ECT has been applied to a bed of wet granulate material. This was accomplished through the use of a novel dynamic correction technique which accounts for the significant reduction in electrical permittivity occurring as moisture is lost during the drying process. The correction has been independently verified using x-ray tomography. <p>Investigation of the ECT images taken in the drying bed indicates centralized bubbling behaviour for approximately the first 5 minutes of drying. This behaviour is a result of the high liquid loading of the particles at high moisture. Between moisture contents of 18-wt% and 10-wt%, the tomograms show an annular pattern of bubbling behaviour with a gradual decrease in the cross-sectional area involved in bubbling behaviour. The dynamic analysis of this voidage data with the S-statistic showed that a statistically significant change occurs during this period near the walls of the vessel, while the centre exhibits less variation in dynamic behaviour. The changes identified by the S-statistic analysis of voidage fluctuations near the wall were similar to those seen in the pressure fluctuation measurements. This indicates that the source of the changes identified by both these measurement techniques is a result of the reduction in the fraction of the bed cross-section involved in bubbling behaviour. At bed moisture contents below 5-wt%, rapid divergence was seen in the S-statistic applied to both ECT and pressure fluctuation measurements. This indicates that a rapid change in dynamics occurs near the end of the drying process. This is possibly caused by the entrainment of fines at this time, or the build-up of electrostatic charge. <p>The use of the complimentary pressure fluctuation and ECT measurement techniques have identified changes occurring as a result of the reduction of moisture during the drying process. Both the localized changes in the voidage fluctuations provided by the ECT imaging and the global changes shown by the pressure fluctuation measurements indicate significant changes in the dynamic behaviour caused by the reduction of moisture during the drying process. These measurement techniques could be utilized to provide an on-line indication of changes in hydrodynamic regime. This information may be invaluable for the future optimization of the batch drying process and accurate determination of the drying endpoint.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In this work a parameterization for the transport terms of the turbulent kinetic energy (TKE) budget equation, valid for a convective boundary layer (CBL) is presented. This is a hard task to acomplish from experimental data, especially because of the difficulty associated to the measurements of pressure turbulent fluctuations, which are necessary to determine the pressure correlation TKE transport term. Thus, employing a large eddy symulation (LES), all terms of the TKE budget equation were determined for a CBL. From these data, polynomials that describe the TKE transport terms vertical profiles were adjusted for a CBL. The found polynomial fits are a good description of the LES data, and from them it is shown that a simple formulation that directly relates the transport terms to the TKE magnitude has advantages on other parameterizations commonly used in CBL numerical models. Furthermore, the present study shows that the TKE turbulent transport term dominates over the TKE transport by pressure perturbations and that for most of the CBL these two terms have apposite signs. The simulation consists of a full diurnal PBL cycle utilizing, at the surface, a forcing obtained from experimental data, so that the numerical experiment represents a more realistic case than a idealized CBL. / Neste trabalho, uma parametrização para os termos de transporte da equação de balanço de energia cinética turbulenta (ECT), válida para uma camada limite convectiva (CLC), é apresentada. Esta é uma tarefa complicada de ser realizada a partir de dados experimentais, especialmente devido a dificuldade associada às medidas das flutuações de pressão, que são necessárias para a determinação do termo de correlação de pressão. Desta forma, empregando a simulação dos grandes turbilhões (LES, do inglês Large Eddy Simulation), todos os termos da equação de balanço de ECT foram determinados para a CLC. A partir desses dados, foram ajustados polinômios que descrevem os perfis verticais dos termos de transporte para a CLC. Os polinômios obtidos fornecem uma boa descrição dos dados da simulação LES, e em função deles é mostrado que uma formulação simples, que se relaciona com os termos de transporte a partir da ECT, apresenta vantagens em relação a outras paramametrizações comumente empregadas em modelos numéricos para a CLC. Além disso, o presente estudo mostra que o termo de transporte turbulento domina sobre o transporte devido a flutuações de pressão, e que para a maior parte da extensão vertical CLC estes dois termos tem sinais opostos. A simulação consiste em um ciclo diário da CLP, utilizando como forçante de superfície dados obtidos experimentalmente, assim o experimento numérico representa um caso mais realista que uma simulação de CLC estacionária.

No description available.

O Protocolo de Quioto foi ratificado em Fevereiro de 2005 e com isso um mercado que vinha caminhando sem regras formais, contando com o pioneirismo de algumas empresas interessadas em aprender a lidar com esta nova commodity e preocupadas com a sua imagem corporativa, passou de fato às vias da formalidade. Assim, uma vez que o mercado de Reduções Certificadas de Emissões (RCEs) possui um arcabouço institucional estabelecido, é interessante estudar com base na Economia dos Custos de Transação (ECT), como os custos de transação induziram modos alternativos de governança, em particular os contratos entre empresas proponentes de projetos de MDL (Mecanismo de Desenvolvimento Limpo) e os canais de comercialização constituídos por organizações multilaterais. E esse estudo, conforme as recomendações de Williamson (1993; 1991; 1985), foi feito analisando as características das transações em termos de especificidade de ativos, freqüência e incerteza, dados os pressupostos comportamentais dos agentes (racionalidade limitada e oportunismo). Para tanto, a pesquisa lançou mão do método do estudo de caso para obter informações privadas sobre as transações de RCEs, e seus respectivos contratos, entre as empresas brasileiras e uma organização multilateral, o Banco Mundial. Um resultado é que, diferente das relações via mercado, as empresas brasileiras se beneficiaram - em termos de redução dos custos de transação - da transação de RCEs (via contrato) com o Banco Mundial, já que este exerce todas as funções de um típico canal de distribuição, exceto a de aquisição dos direitos de propriedade sobre os créditos. / The Kyoto Protocol was approved in February 2005 and the carbon market that was without rules, played by some pioneer companies interested in learning by doing with this new commodity and worried about their corporate image, started working in the ways of the formality. As the market of Certified Emissions Reduction (CER) has already an established Institutional Environment, it’s interesting to study, based on the Transaction Costs Economics (TCE) theory, how the transaction costs induced alternative ways of governance, in particular the contracts between Brazilian companies – with CDM (Clean Development Mechanism) projects - and the commercialization channels in multi-lateral organizations. This study, as the recommendations of Williamson (1993; 1991; 1985), was made analyzing the characteristics of the transactions in terms of asset specificity, frequency and uncertainty, considering the human behavior assumptions (limited rationality and opportunism). For this, the research used the case studies method to obtain private information about the transactions of CER, and their contracts, between Brazilian companies and a multi-lateral organization, the World Bank. A result is that, differently of the spot market relationship, the Brazilian CDM projects benefited - in terms of reduction of transaction costs – with the CERs transactions (contracts) involving the World Bank, since this bank realizes every distribution channel functions, except the acquisition of CERs property rights.