In the past, radial-mode piezoelectric transformer (Transoner) design has been difficult due to the complex interaction between the physical and electrical circuit characteristics. Prior to a design procedure, experimental design by Face Electronics, LC led to a sample that could fit a ballast application enabling zero voltage switching (ZVS) for the semiconductors without the use of any external inductance. In the ballast circuit, the piezoelectric transformer is used to replace the conventional inductor-capacitor resonant tank saving valuable space and expense. With ballast in mind, a design process has been developed in this thesis to optimize radial mode transformers to fit specifically tailored applications. The graphical process described, allows the engineer to design in the capability of zero voltage switching for a half-bridge drive while simultaneously providing highly efficient performance. The problem of mounting a piezoelectric transformer to a circuit board has also been addressed in this thesis. A thermally conductive mounting technique has been developed which can enhance both the power capability and reliability of circuits utilizing these devices. / Master of Science

The key to improving drying quality and reducing drying time and energy consumption lies in understanding and controlling moisture movement during drying. As wood dries, strains and stresses develop as a result of restraints imposed by moisture gradients and differential shrinkage in wood. So accurately measuring the moisture gradient in wood during drying will be helpful to improving drying quality. In this project, moisture gradients in red oak will be measured through four different techniques----<i><b>bandsaw slicing, Forstner bit layering, flaking and razor blade slicing</i></b>. The first two techniques are found in the literature. The last two are developed in this study. The results obtained with these four techniques were compared, and it was found that the newly developed techniques could get moisture gradients that were closer to the true value. The <i><b>thickness</i></b> of the slice was assumed to affect measuring the moisture gradient because of the environmental influences. So a thickness series was tested with the two new technique----flaking and razor blade slicing. The results showed that there was no slice or flake thickness effect on the moisture gradients.And an optimum slice and flake thickness was determined for the wood industries and research studies. Finally, the <i><b>directional</i></b> effect on transverse moisture movement during kiln drying was examined through measuring moisture gradients in the tangential and radial directions of wood. The results showed that moisture moved slightly faster in the radial direction than in the tangential direction during kiln drying and the moisture gradients in the tangential direction were slightly steeper than those in the radial direction. / Master of Science

OBJETIVO: Avaliar a eficácia, estabilidade, previsibilidade e segurança da ceratectomia fotorrefrativa (PRK) guiada pelas frentes de onda corneana para o tratamento da hipermetropia secundária à ceratotomia radial (CR). MÉTODOS: Foram avaliados prospectivamente 61 olhos de 39 pacientes consecutivos, submetidos a PRK personalizado com o laser Esiris-Schwind. A técnica constou de desepitelização mecânica, fotoablação, e utilização de mitomicina C (MMC) 0,02% por 20 ou 40 segundos. A MMC foi aplicada por 40 segundos em 17 olhos (27,9%) que haviam sido submetidos a ablações mais profundas do que 100 ?m ou apresentavam córneas previamente suturadas. As avaliações pós-operatórias foram realizadas após sete dias, um, seis, 12 e 24 meses. Todos os olhos foram avaliados após um ano e dois anos. RESULTADOS: O intervalo médio entre a CR e o PRK foi de 18,8 anos ± 3,8 (DP); o equivalente esférico (EE) médio antes da ceratotomia radial era -4,10 dioptrias (D) ± 1,44. As medidas prévias ao PRK mostraram EE médio de +4,17 D ± 1,97; astigmatismo médio de -1,39 D ± 1,04; AV com correção (AVcc) média de 0,161 ± 0,137 (logMAR); e curvatura corneana média de 35,85 ± 3,60 D. Os resultados encontrados dois anos após a cirurgia foram: EE médio de 0,14 ± 0,99 D (p < 0,001); astigmatismo médio de -1,19 ± 1,02 D (p = 0,627); AV sem correção (AVsc) média de 0,265 ± 0,196 (p < 0,001); AVcc média de 0,072 ± 0,094 (p < 0,001); e curvatura corneana média de 39,01 ± 3,18 D (p < 0,001). AVsc igual ou melhor a 20/25 foi observada em 38% dos olhos e igual ou melhor a 20/40 em 69%. A AVcc melhorou em 62,3% dos olhos, sendo que 21 olhos (34,4%) melhoraram uma linha e outros 17 olhos (27,9%), duas ou mais linhas. Um olho (1,6%) perdeu duas linhas devido ao astigmatismo irregular ocasionado por opacificação corneana periférica. Outro olho perdeu três linhas pelo desenvolvimento de ectasia corneana entre seis e 24 meses, devido ao alargamento progressivo de uma incisão radial inferior, e foi posteriormente submetido à sutura da incisão. Houve 30 olhos (49,2%) entre ± 0,50 D do EE planejado e 45 (73,8%) entre ± 1,00 D. Entre seis e 24 meses, a regressão média do EE foi de +0,39 D (p < 0,05) e cinco olhos (8,3%) sofreram desvio hipermetrópico > 1,00 D. Ocorreu redução estatisticamente significante do coma (p = 0,001), trefoil (p = 0,008), aberração esférica (p < 0,001), astigmatismo secundário (p = 0,001) e quatrefoil (p < 0,001). Não houve mudança estatisticamente significativa da contagem endotelial (p = 0,161). Dois olhos (3,3%) desenvolveram opacificação corneana periférica grau 2 e um, grau 3. CONCLUSÃO: O PRK personalizado pelas frentes de onda corneana coadjuvado pela MMC foi eficaz, previsível e seguro pelo período de dois anos para a redução da hipermetropia após a CR. No pós-operatório observou-se melhora significativa da AVsc, AVcc e das aberrações corneanas. Constatou-se, entretanto, que a hipermetropia consecutiva à CR continua a progredir após o tratamento com o excimer laser. / PURPOSE: To assess the efficacy, stability, predictability and safety of corneal wavefront-guided photorefractive keratectomy (PRK) for correcting hyperopia after radial keratotomy (RK). METHODS: In a prospective study, 61 eyes of 39 consecutive patients were treated with PRK using an Esiris-Schwind excimer laser. Corneal epithelium was mechanically removed, followed by photoablation and use of 0.02% mitomycin C (MMC) for 20 or 40 seconds. MMC was used for 40 seconds in 18 eyes (27.9%) which underwent ablations deeper than 100 micron or had previous corneal sutures. Postoperative evaluations were performed after seven days, six, 12 and 24 months. All patients were followed up for two years. RESULTS: The mean time between RK and PRK was 18.8 years ± 3.8 (SD); mean spherical equivalent (SE) before RK was -4.10 diopters (D) ± 1.44. Before PRK, the mean SE was +4.17 D ± 1.97, mean astigmatism was -1.39 D ± 1.04, the mean best-corrected visual acuity (BCVA) was 0.161 ± 0.137 (logMAR) and the mean corneal curvature was 35.85 ± 3.60 D. At 24 months, mean SE was 0.14 ± 0.99 D (p < 0.001), mean astigmatism was -1.19 ± 1.02 D (p = 0.627), mean UCVA was 0.265 ± 0.196 (p < 0.001), mean BSCVA was 0.072 ± 0.094 (p < 0.001) and the mean corneal curvature was 39.01 ± 3.18 D (p < 0.001). UCVA was 20/25 or better in 38% of eyes and 20/40 or better in 69%. BCVA improved in 62.3% of eyes, with 21 (34.4%) gaining one line and 17 (27.9%), two or more lines. One eye (1.6%) lost two lines due to irregular astigmatism and peripheral haze. Another eye lost three lines due to keratectasia occurring between six and 24 months resulting from widening of an inferior radial incision that was later sutured. Thirty eyes (49.2%) were within ± 0.50 D of intended SE and 45 (73.8%) were within ± 1.00 D. From six to 24 months, the mean SE regression was +0.39 D (p < 0.05) and five eyes (8.3%) had a hyperopic shift > 1.00 D. A significant decrease in coma (p = 0.001), trefoil (p = 0.008), spherical aberration (p < 0.001), secondary astigmatism (p = 0.001) and quatrefoil (p < 0.001) was observed. Endothelial cell counts did not show a statistically significant decrease (p = 0.161). Two eyes (3.3%) developed peripheral haze grade 2 and one, grade 3. CONCLUSION: Corneal wavefront-guided PRK with MMC was effective, predictable and safe after two years for the treatment of hyperopia after RK. A significant improvement in UCVA, BSCVA and corneal aberrations was obtained. However, hyperopic shift after RK continued to progress after excimer laser surgery.

Neste trabalho estudamos a questão de simetria de soluções positivas de equações e sistemas de equações diferenciais parciais. Descrevemos em detalhe a demonstração de dois resultados sobre simetria radial, um para equações em domínios limitados e outro para sistemas de equações no espaço todo. Ambas as demonstrações baseiam-se no método dos moving planes. Em seguida aplicamos um dos resultados mencionados acima para a equação de Choquard. / In this work we study the question of symmetry for positive solutions of equations and systems of partial differential equations. We describe in detail the proof of two results on radial symmetry, one for equations in bounded domains and the other for systems of equations in the whole space. Both proofs are based on the method of moving planes. We apply one of the results mentioned above for the Choquards equation.

This doctoral research was realized within the frame of the SMARTNET Project which aimed at developing coatings to improve the cleanability of stainless steel, targeting open surface applications. Throughout this thesis, the radial-flow cell was selected to study the removal of different soils due to its ability to generate well-controlled wall shear stress distributions on the investigated surfaces. Model surfaces were selected for their different physico-chemical and mechanical properties to study the interactions between the soils and the surfaces in detail. A thin layer chromatography sprayer giving a narrower and more reproducible droplet sizes distribution was preferred to mimic splashing and produce controlled spatters. The first experimental campaign involving oil droplets showed that the analytical models available to relate the detachment radius with the critical wall shear stress (minimal wall shear stress required for soil detachment) and the soil adhesion strength in the radial flow cell could only be applied for weakly adherent soils for which removal occurs below 3 Pa, due to the complex hydrodynamics near the inlet. Consequently, the flow inside the radial-flow cell has been characterized using computational fluid dynamics over the whole inlet laminar regime and validated experimentally. Studying the adherence of starch granule aggregates in the radial-flow cell revealed that the conversion of critical radius into critical wall shear stress may be biased when the adhering aggregate height is not negligible with respect to the channel height and when the adherence is such that flow rates above creeping flow conditions are required for soil detachment. The influence of several environmental factors and substrate properties was then examined to improve the understanding of the mechanisms affecting soiling and cleanability. By influencing droplet spreading and competition between capillary forces at the granule-substrate and granule-granule interfaces, substrate wettability affects the shape and compactness of the adhering aggregates, the efficiency of shear forces upon cleaning, and finally the adherence of soiling particles. Macromolecules originating from the starch granules suspension are adsorbed on the substrate from the liquid phase or carried by the retracting film and accumulated at the granule-substrate interface. They influence granule adherence by acting as an adhesive joint, the properties of which seem to be influenced by the detailed history of drying and exposure to humidity. On compliant substrates, the aggregate-substrate interactions induce stresses at the granule-substrate interface which may lead to substrate deformation and promote a more intimate contact between the granules and their substrate, thereby appreciably increasing adherence.

In this thesis, we propose a new class of learning models, namely the additive generalized radial basis function networks (AGRBFNs), for general nonlinear regression problems. This class of learning machines combines the generalized radial basis function networks (GRBFNs) commonly used in general machine learning problems and the additive models (AMs) frequently encountered in semiparametric regression problems. In statistical regression theory, AM is a good compromise between the linear model and the nonparametric model. In order for more general network structure hoping to address more general data sets, the AMs are embedded in the output layer of the GRBFNs to form the AGRBFNs. Simple weights updating rules based on incremental gradient descent will be derived. Several illustrative examples are provided to compare the performances for the classical GRBFNs and the proposed AGRBFNs. Simulation results show that upon proper selection of the hidden nodes and the bandwidth of the kernel smoother used in additive output layer, AGRBFNs can give better fits than the classical GRBFNs. Furthermore, for the given learning problem, AGRBFNs usually need fewer hidden nodes than those of GRBFNs for the same level of accuracy.

Made available in DSpace on 2014-06-11T19:30:32Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-03-20Bitstream added on 2014-06-13T19:19:27Z : No. of bitstreams: 1 lucks_mb_dr_ilha.pdf: 2462450 bytes, checksum: 86757d12f991c55cad8d80bcd63f9b61 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Neste trabalho, apresenta-se o desenvolvimento de redes de base radial em tecnologia CMOS. Para tanto, dois circuitos unidimensionais, denominados RBF1 e RBF2, são propostos. Sua funcionalidade é demonstrada por meio de simulações SPICE e também pela sua implementação prática com a utilização de conjuntos de MOSFETs presentes em circuitos integrados comerciais. Demonstra-se também o desenvolvimento dos circuitos para o caso multidimensional, com o uso de simulações SPICE e a implementação de um circuito RBF1 bidimensional. Além disso, são apresentadas versões dos circuitos RBF1 e RBF2 para tecnologia BiCMOS. Os circuitos propostos são utilizados no projeto de redes de base radial bidimensionais em processo CMOS AMS 0.35 μm. No intuito de testar sua funcionalidade, as redes foram simuladas para algumas aplicações, apresentando bons resultados. A questão da quantização no armazenamento dos parâmetros das redes de base radial e da sua influência na aproximação de funções também é tratada na tese. Foram realizadas várias simulações com diferentes níveis de quantização para algumas tarefas de aproximação de funções. Os resultados obtidos mostram que, mesmo com uma quantização severa, as redes apresentam a capacidade de aproximação de funções, porém de maneira limitada, ou seja, o erro obtido aumenta para um número menor de níveis de quantização. A quantização dos parâmetros diminui o tamanho da memória e a complexidade necessária para armazenar os parâmetros das redes, permitindo a implementação de circuitos compactos e adequados para aplicações de baixo consumo de potência. / In this work, we present the development of radial basis function circuits in CMOS technology. Two one-dimensional circuits, namely RBF1 and RBF2, are proposed for radial basis function realization, and their functionality is demonstrated by SPICE simulations and by their implementation with commercial MOSFET array integrated circuits. Multidimensional capability is demonstrated by the implementation of a bidimensional RBF1 circuit and by SPICE simulation results. In addition, BiCMOS versions are also presented for RBF1 and RBF2. The proposed cells are used in the design of bidimensional radial basis function neural networks in AMS 0.35μm CMOS process. In order to test their functionality, the networks were simulated for some applications with good results achieved. The issue of parameter quantization and its influence on the network function approximation capability is also dealt with in this dissertation. We carried out several simulations with different levels of quantization. The results obtained show that the network presents a capability of learning functions, even with a severe parameter quantization. As expected, the error increases for less bits of quantization. Nevertheless, the parameter quantization decreases the memory size and complexity necessary for network parameter storage, allowing the implementation of compact circuits and being adequate for low power applications.

In this thesis, we analyse multilevel collocation methods involving compactly supported radial basis functions. We focus on linear second-order elliptic bound- ary value problems as well as Darcy's problem. While in the former case we use scalar-valued positive definite functions for constructing multilevel approximants, in the latter case we use matrix-valued functions that are automatically divergence-free. A similar result is presented for interpolating divergence-free vector fields. Even though it had been observed more than a decade ago that the stationary setting, i.e. when the support radii shrink as fast as the mesh norm, does not lead to convergence, it was up to now an open question how the support radii should depend on the mesh norm to ensure convergence. For each case above, we answer this question here thoroughly. Furthermore, we analyse and improve the stability of the linear systems. And lastly, we examine the case when the approximant does not lie in the same space as the solution to the PDE.

Base teórica A síndrome do túnel do carpo (STC) é uma lesão compressiva nervosa mais comum que afeta o nervo mediano observada na prática clínica. Existem muitas técnicas eletrofisiológicas para diagnosticar a STC, mas a maioria dispende muito tempo, é dolorosa e tem sensibilidade variada. Objetivo Avaliar a acurácia de um método eletrofisiológico de investigação da STC e correlaciona-lo com aspectos clínicos. Métodos Pacientes do ambulatório de Neurologia com critérios clínicos para STC foram submetidos a uma bateria de testes clínicos e neurofisiológicos. Primeiramente, nós aplicamos o Questionário de Síndrome do túnel do Carpo de Boston e Escala visual analógica (EVA). Após, realizamos o método eletrofisiológico convencional de avaliação sensitiva do nervo mediano e ulnar. Posteriormente, outro médico eletrofisiologista, cegado para as avaliações anteriores, realizou a técnica de estimulação simultânea dos nervos mediano e radial no polegar com registro simultâneo de ambos potenciais na região punho. Os dados foram agrupados em STC leve, moderada e grave, baseados na latência motora do nervo mediano. Resultados A latência entre picos (LEP), obtida pela técnica em estudo, foi diferente entre os grupos baseados na classificação de gravidade da STC (Bonferroni; p<0.001). A velocidade de condução nervosa sensitiva do nervo mediano, obtida através da técnica standard, apresentou também diferentes valores entre os grupos. Houve correlação entre LEP e velocidade de condução nervosa sensitiva do mediano (Sperman; r=-0.52; p<0.01), bem como entre LEP e velocidade de condução nervosa sensitiva do mediano com o desconforto causado pela STC mensurado pela Escala visual analógica (EVA). A duração e o desconforto causado pela técnica de estimulação simultânea do nervo mediano e radial estão reduzidos quando comparados com a técnica padrão (t Student; p< 0.001 para as duas comparações). Conclusão A técnica de estimulação simultânea do nervo mediano e radial é acurada, sensível, tolerável e não somente útil no diagnóstico da STC, mas também na definição da gravidade. Então, seu uso deve ser encorajado na prática clínica. / Background Carpal tunnel syndrome (CTS) is the most common nerve entrapment observed in clinical practice affecting the median nerve at the wrist level. There are many electrophysiological ways to diagnose CTS, but most of them are time consuming, painful and have variable sensitivity. Objective To evaluate the accuracy of an electophysiologic method of CTS investigation and to correlate it with clinical symptoms. Methods Patients at the clinic outpatient Neurology with CTS clinical criteria underwent a battery of clinical and neurophysiological tests. First, we applied the Boston Carpal Tunnel Syndrome Questionnaire (BCTQ) and Visual analogue scale (VAS). After, we performed a standard method of analysis of the median and ulnar nerves. Posteriorly, a blinded neurophysiologist performed an orthodromic median-radial nerve simultaneous stimulation at the thumb with recording of both action potentials at the lateral aspect of the wrist. Data were grouped for mild, moderate and severe CTS, based on median motor latency. Results The interpeak latency (IPL), obtained with study technique, was different in groups based on CTS classification severity (Bonferroni. p<0.001). The median nerve conduction velocity, obtained with the standard approach, was also of different level among groups. There were correlation between IPL and median nerve conduction velocity (Sperman; r=-0.52; p<0.01), as well as, there was a significant correlation between IPL and median nerve conduction velocity with the discomfort caused by CTS and measured with VAS. However, the duration and unpleasantness caused by median-radial nerve simultaneous stimulation technique were reduced when compared to standard approach (t Student <0.001 for both comparisons). Conclusion The orthodromic median-radial nerve simultaneous stimulation technique is accurate, sensitive, tolerable and not only useful for CTS diagnosis but also for its severity assessment. Therefore, its use should be encouraged in clinical practice.

Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro / Neste estudo qualitativo, objetiva-se descrever os usos do conector mas em um corpus de mediação endoprocessual, à luz da Linguística Cognitiva, baseando-se, sobretudo, na Teoria da Metáfora Conceptual e nos conceitos de categorização, esquemas imagéticos e modelos cognitivos idealizados (MCIs). Investigam-se as bases cognitivas que fundamentam os sentidos do mas e a função argumentativa desse conector na mediação, a partir de duas hipóteses gerais, a saber: (i) defende-se que o conector mas funciona como um gatilho para a ativação do MCI de guerra, em termos do qual é conceptualizado o conceito de discussão, como afirmam Lakoff e Johnson (2002[1980]); e (ii) acredita-se que tal conector possa ser caracterizado como uma categoria radial, formada a partir dos diferentes esquemas imagéticos que fundamentam as ocorrências desse elemento na interação. Tendo em vista essas hipóteses, objetiva-se: (i) apontar as funções argumentativas do mas na mediação, sinalizadas pelos mapeamentos metafóricos ativados durante a discussão e (ii) descrever os sentidos evidenciados pelos usos do mas no gênero analisado, os quais são evocados pelos diferentes esquemas imagéticos em que se baseiam. Os resultados indicam que esse conector pode ser compreendido como uma categoria radial, formada a partir de esquemas de força distintos. Além disso, verifica-se que os três usos mais próximos ao centro da categoria relacionam-se fortemente a um confronto ou a uma disputa de posição entre os participantes da interação, enquanto os três mais periféricos são estreitamente ligados a uma estratégia de manutenção da posição argumentativa do falante. Considera-se que esta pesquisa possa colaborar para o estudo do conector mas, devido à observação do comportamento semântico-discursivo desse item em um gênero pouco contemplado, a mediação; e, devido à escolha do paradigma adotado, que permite analisar o conector em todas as suas ocorrências, não havendo necessidade de separar os usos chamados de interfrásticos daqueles denominados inícios acessórios ou pré-começos / This qualitative study aims to describe the usage of the connector but, in a corpus of mediation, under the light of Cognitive Linguistics, mainly based on the Theory of Conceptual Metaphor and in the concepts of categorization, image schema and idealized cognitive models (ICMs). The cognitive bases that underlie the meanings of the connector but, as well as its argumentative function in mediation, will be investigated from two general hypothesis: (i) it is defended that the connector but functions as a trigger to the activation of the ICM of war, in which the concept of discussion is conceptualized, as affirmed by Lakoff and Johnson (2002[1980]); and (ii) it is believed that the aforementioned connector can be characterized as a radial category, formed from the different image schemas that underlie the occurrences of this element on the interaction. Taking into account these hypotheses, we aim to: (i) indicate the argumentative functions of but in the mediation, signaled by metaphorical mappings activated during the discussion and (ii) describe the meanings stressed by the uses of but in the analyzed genre, meanings that are evoked by the different image schemas in which they are based on. The results indicate that this connector may be seen as a radial category, formed by distinct force schemas. Besides that, we verified that the three uses closer to the center of the category are strongly related to a confrontation or a dispute of position between the interaction participants, while the three more peripheral are tightly linked to a strategy to maintain the argumentative position of the speaker. This research is considered a collaboration to the study of the connector but, due to the observation of this items semantic-discursive behavior in a little addressed genre, i.e., mediation; and, because of the adopted paradigm, which allows the analysis of the connector in all occurrences, there is no need to separate the uses of but that appear between the conjunctions from those that appear in the beginning of the utterances