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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
141

Descrição comparativa do padrão angular em bicicleta estacionária, modalidade indoor, chassi fixo e articulado

Pinzon, Cassiano January 2012 (has links)
A bicicleta estacionária articulada é um tipo de equipamento disponibilizado recentemente ao mercado de fitness, consequentemente não explorado em estudos no meio acadêmico científico. Desta forma surgem alguns problemas de pesquisas, desde o fato da instrumentação deste equipamento até a escolha de metodologias e variáveis a serem estudadas para potencializar o seu uso. Este estudo foi realizado com o proposito de descrever as diferenças quanto ao padrão angular da pedalada do ciclista, ou seja, o ângulo do pedal relativo ao pedivela, utilizando-se desta nova bicicleta estacionária de ciclismo indoor, comparando a condição chassi fixo com o articulado. Para a instrumentação, foi acoplado um gerador e um encoder junto a roda de inércia tendo controle das variáveis carga e cadência. Para a medição do ângulo do pedal, os pedais (direito e esquerdo) da bicicleta foram substituídos por pedais instrumentados com potenciômetros, já para o registro do ângulo do pedivela, foi utilizado um sensor eletromagnético, do tipo reed switch. A amostra foi composta por cinco praticantes, todos devidamente adaptados com bicicletas de chassi articulado, submetidas a um protocolo pré-estabelecido, variando condição (fixo e articulado) e posição (pedalando no selim e em pé) com carga e cadência determinada. Embora a amplitude de movimento para ambos os pedais não apresentaram diferenças, em análise, os resultados apontaram que o uso do chassi articulado afeta o padrão angular do pedal durante o ciclo da pedalada, menos acentuado quando utilizou-se a posição sentado no selim, e mais acentuado quando estava-se pedalando em pé. Das posições no pedivela que apresentaram as diferenças no padrão angular durante o uso do chassi articulado, 80% foram na parte produtiva da pedalada (ângulo de 0° a 180°), e o ângulo de 150° concentrou 60% destas ocorrências. Já, tratando-se de forças no pedal, o chassi articulado apresenta evidência de ser mais eficiente do que o chassi fixo. / The stationary articulated bicycle is a type of equipment which is available to the fitness market only recently, and therefore it was not investigated in academic or scientific studies yet. Thus, this fact arises some problems of research, from the fact of instrumentation of this equipment to the choice of methods and variables to be studied to maximize its use. This study was conducted with the purpose to describe the differences in the angular pattern of cyclist pedaling, i.e., the angle on the pedal crank, using this new stationary bicycle of indoor cycling, by comparing the condition of the fixed chassis with the articulated one. For the instrumentation, a generator and an encoder were connected to the wheel of inertia, taking control of the load and cadence variables. To measure the angle of the pedal, the left and right pedals of the bicycle were replaced by pedals which were instrumented with potentiometers. To record the angle of the crank, we used an electromagnetic sensor, the reed switch. The sample consisted of five practitioners, all suitably adapted with articulated frame bicycles, which were subjected to a pre-established protocol, varying the condition (fixed or articulated), and the position (pedaling in the saddle or standing up), with determined load and cadence. The results indicated that the use of articulated frame affects the pattern of the pedal angle during the pedaling cycle, less marked when the sitting position on the saddle was used, and more pronounced when pedaling on the standing up position. About the positions of the crank that showed differences in angle while using the articulated frame: 80% were in the productive part of the pedaling (angle from 0° to 180°), and the angle of 150° concentrated 60% of these incidents. The amplitude of angular movement of the pedal showed no differences between fixed and articulated frame. However, in the case of forces on the pedal, the articulated frame shows evidence of being more efficient than the fixed frame.
142

Právní úprava ochrany kvality ovzduší / Legal regulation of air quality protection

Glozyga, Dušan January 2018 (has links)
This thesis deals with the issues associated with the legal regulation of air quality protection. The main objective is to describe, analyse and evaluate the condition of the current legal regulation which is mainly represented by the Act no. 201/2012 Coll., on the protection of air. The introductory part of the thesis focuses on the historical development of the legal regulation, its primary milestones, as well as legal regulation according to International and European Law and its impact on the internal national legislation. Furthermore, the thesis also focuses on the currently valid legal regulation and its components and clarifies its basic terminology. The largest portion of the thesis focuses on the legal regulation of the individual instruments regulated primarily by the Act no. 201/2012 Coll., on the protection of air, with the primary focus being the stationary sources of pollution. These instruments are sorted into traditional groups, each respectively representing conceptual, administrative-legal and economic instruments. The chapter on conceptual instruments primarily focuses on the two fundamental instrumental programs, that is a) - The National Emission Reduction Program of the Czech Republic, and b) - programs aimed at improving air quality and their importance in legal regulation....
143

TOMOGRAPHIC IMAGE RECONSTRUCTION: IMPLEMENTATION, OPTIMIZATION AND COMPARISON IN DIGITAL BREAST TOMOSYNTHESIS

Xu, Shiyu 01 December 2014 (has links)
Conventional 2D mammography was the most effective approach to detecting early stage breast cancer in the past decades of years. Tomosynthetic breast imaging is a potentially more valuable 3D technique for breast cancer detection. The limitations of current tomosynthesis systems include a longer scanning time than a conventional digital X-ray modality and a low spatial resolution due to the movement of the single X-ray source. Dr.Otto Zhou's group proposed the concept of stationary digital breast tomosynthesis (s-DBT) using a Carbon Nano-Tube (CNT) based X-ray source array. Instead of mechanically moving a single X-ray tube, s-DBT applies a stationary X-ray source array, which generates X-ray beams from different view angles by electronically activating the individual source prepositioned at the corresponding view angle, therefore eliminating the focal spot motion blurring from sources. The scanning speed is determined only by the detector readout time and the number of sources regardless of the angular coverage spans, such that the blur from patient's motion can be reduced due to the quick scan. S-DBT is potentially a promising modality to improve the early breast cancer detection by providing decent image quality with fast scan and low radiation dose. DBT system acquires a limited number of noisy 2D projections over a limited angular range and then mathematically reconstructs a 3D breast. 3D reconstruction is faced with the challenges of cone-beam and flat-panel geometry, highly incomplete sampling and huge reconstructed volume. In this research, we investigated several representative reconstruction methods such as Filtered backprojection method (FBP), Simultaneous algebraic reconstruction technique (SART) and Maximum likelihood (ML). We also compared our proposed statistical iterative reconstruction (IR) with particular prior and computational technique to these representative methods. Of all available reconstruction methods in this research, our proposed statistical IR appears particularly promising since it provides the flexibility of accurate physical noise modeling and geometric system description. In the following chapters, we present multiple key techniques of statistical IR to tomosynthesis imaging data to demonstrate significant image quality improvement over conventional techniques. These techniques include the physical modeling with a local voxel-pair based prior with the flexibility in its parameters to fine-tune image quality, the pre-computed parameter κ incorporated with the prior to remove the data dependence and to achieve a predictable resolution property, an effective ray-driven technique to compute the forward and backprojection and an over-sampled ray-driven method to perform high resolution reconstruction with a practical region of interest (ROI) technique. In addition, to solve the estimation problem with a fast computation, we also present a semi-quantitative method to optimize the relaxation parameter in a relaxed order-subsets framework and an optimization transfer based algorithm framework which potentially allows less iterations to achieve an acceptable convergence. The phantom data is acquired with the s-DBT prototype system to assess the performance of these particular techniques and compare our proposed method to those representatives. The value of IR is demonstrated in improving the detectability of low contrast and tiny micro-calcification, in reducing cross plane artifacts, in improving resolution and lowering noise in reconstructed images. In particular, noise power spectrum analysis (NPS) indicates a superior noise spectral property of our proposed statistical IR, especially in the high frequency range. With the decent noise property, statistical IR also provides a remarkable reconstruction MTF in general and in different areas within a focus plane. Although computational load remains a significant challenge for practical development, combined with the advancing computational techniques such as graphic computing, the superior image quality provided by statistical IR will be realized to benefit the diagnostics in real clinical applications.
144

Um método para extração de lesões em imagens de linfoma baseado em transformada wavelet estacionária

Duarte, Sidon Cléo January 2015 (has links)
Orientador: Prof. Dr. Marcelo Zanchetta do Nascimento / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Engenharia da Informação, 2015. / Linfoma é um tipo de tumor que afeta o sistema linfático humano, em que se estima mais de 60 subtipos de canceres distintos, derivados de 2 grandes grupos: Hodgkins e os não Hodgkins (NHL). De difícil classificação e diagnóstico, para a maioria dos casos a biópsia é a única maneira de saber se um nódulo é realmente linfoma. Atualmente a maioria dos sistemas de classificação deste tipo de linfoma é baseada unicamente na avaliação de um especialista através do auxilio de microscópio. Este trabalho tem como objetivo apresentar um método automático para classificar imagens histológicas dos três tipos de linfomas NHL mais recorrentes. Linfoma de celulas do manto (LCM), Linfoma Folicular (LF) e Leucemia Linfoide Cronica (LCM). O método baseia-se na transformada wavelet estacionária (TWE) como extrator de características, a técnica TWD como seletor de atributos e redução de dimensionalidade e a classificação através do classificador SVM com o kernel RBF. Foi utilizado, no trabalho, um banco de 30 lâminas histológicas de linfonodos, proveniente de estudos realizados por pesquisadores do Instituto Nacional do Câncer (National Cancer Institute) e Instituto Nacional do Envelhecimento (National Institute on Aging), nos Estados Unidos. Os experimentos foram realizados com 240 imagens, sendo 70 de cada classe, nos canais de cores do modelo RGB (do Inglês Red, Green and Blue) e níveis de cinza. Foi comparado o desempenho não só entre as subbandas geradas pelas transformada TWE e a transformada wevelet discreta (TWD), mas também entre os canais de cores e os grupos de imagens em classificação binária. Foram utilizadas as métricas de acurácia, sensibilidade e especificidade. Resultados relevantes foram obtidos, entre eles: Acurácia de 97,1%, Sensibilidade de 93% e Especificidade de 94%. / Lymphoma is a type of tumor that affects the human lymphatic system, which is estimated more than 60 different subtypes of cancers, derivatives of 2 large groups: Hodgkins and non-Hodgkins Lymphoma (NHL). Due to difficult classification and diagnosis, for most cases, the biopsy is the only way to tell if a lump is really lymphoma. Currently most of classifications methods for this type of lymphoma are based solely on the evaluation of an expert through the microscope help. This work aims to present an automatic method to classification of histological images of the three types of Lympoma NHL most recurrent Cell Lymphoma Mantle (LCM), Lymphoma Follicular (LF) and Chronic Lymphoid Leukemia (CLL). The method is based on the Transform Wavelet Stationary (TWE) as extracting features, the ANOVA technique as selector attributes and dimensionality reduction and classification by the classifier SVM with RBF kernel. The study used a bank of 30 histological slides of lymph nodes, from studies conducted by researchers from the National Cancer Institute and National Institute on Aging in the United States. The experiments were performed with 240 images (70 of each class), on the channels of the model color RGB and gray levels. Comparing the performance not only between the subbands generated by the SWT and Discrete Wavelet Transform (DWT) but also between the color channels and the classification of binary groups of images. The accuracy, sensitivity and specificity metrics were used. Relevant results as accuracy of 97%, 93% of Sensitivity and 94% of Specificity were obtained.
145

Relaxação não-colisional em plasmas não-neutros

Teles, Tarcisio Nunes January 2008 (has links)
Neste trabalho um modelo é apresentado que permite-nos prever quantitativamente o estado estacionário atingido por um plasma não-neutro durante um processo de relaxação nãocolisional. Como uma aplicação específica, a teoria é usada para estudar a relaxação de feixes de partículas carregadas na qual, mostra-se que, um feixe inicialmente casado relaxa para a distribuição de Lynden-Bell. No entanto, quando existe um descasamento inicial, o mesmo oscila e ressonâncias paramétricas conduzem-no a uma separação de fases: caroço e halo. A abordagem desenvolvida vale tanto para a densidade como para a distribuição de velocidade no estado final estacionário. / In this work a theoretical framework is presented which allows us to quantitatively predict the final stationary state achieved by a non-neutral plasma during a process of collisionless relaxation. As a specific application, the theory is used to study relaxation of charged-particle beams. It is shown that a fully matched beam relaxes to the Lynden-Bell distribution. However, when a mismatch is present and the beam oscillates, parametric resonances lead to a corehalo phase separation. The approach developed accounts for both the density and the velocity distributions in the final stationary state.
146

Correlation Between Physiological Fluid Shear and RpoS in Regulating the Stationary Phase Stress Response in Salmonella

January 2016 (has links)
abstract: Salmonella enterica serovar Typhimurium (S. Typhimurium) is a Gram-negative enteric pathogen that causes self-limiting gastroenteritis in healthy individuals and can cause systemic infections in those who are immunocompromised. During its natural lifecycle, S. Typhimurium encounters a wide variety of stresses it must sense and respond to in a dynamic and coordinated fashion to induce resistance and ensure survival. Salmonella is subjected to a series of stresses that include temperature shifts, pH variability, detergent-like bile salts, oxidative environments and changes in fluid shear levels. Previously, our lab showed that cultures of S. Typhimurium grown under physiological low fluid shear (LFS) conditions similar to those encountered in the intestinal tract during infection uniquely regulates the virulence, gene expression and pathogenesis-related stress responses of this pathogen during log phase. Interestingly, the log phase Salmonella mechanosensitive responses to LFS were independent of the master stress response sigma factor, RpoS, departing from our conventional understanding of RpoS regulation. Since RpoS is a growth phase dependent regulator with increased stability in stationary phase, the current study investigated the role of RpoS in mediating pathogenesis-related stress responses in stationary phase S. Typhimurium grown under LFS and control conditions. Specifically, stationary phase responses to acid, thermal, bile and oxidative stress were assayed. To our knowledge the results from the current study demonstrate the first report that the mechanical force of LFS globally alters the S. Typhimurium χ3339 stationary phase stress response independently of RpoS to acid and bile stressors but dependently on RpoS to oxidative and thermal stress. This indicates that fluid shear-dependent differences in acid and bile stress responses are regulated by alternative pathway(s) in S. Typhimurium, were the oxidative and thermal stress responses are regulated through RpoS in LFS conditions. Results from this study further highlight how bacterial mechanosensation may be important in promoting niche recognition and adaptation in the mammalian host during infection, and may lead to characterization of previously unidentified pathogenesis strategies. / Dissertation/Thesis / Masters Thesis Biology 2016
147

Força de reação do solo na corrida estacionária em ambiente aquático e terrestre: efeito do nível de imersão, da cadência do movimento e da densidade corporal / Ground Reaction Forces during Stationary Running in water and on land: Effect of immersion level, movement cadence and body density

Fontana, Heiliane de Brito 28 February 2011 (has links)
Made available in DSpace on 2016-12-06T17:07:29Z (GMT). No. of bitstreams: 1 HEILIANE DE BRITO FONTANA.pdf: 2483011 bytes, checksum: 34f8c30293b3a735afa50fa511307396 (MD5) Previous issue date: 2011-02-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This study aimed to analyze the vertical component peak (Fymáx) of ground reaction forces during stationary running in water and on land. 32 healthy subjects, aged between 20 and 35 years, participated in the study. The sessions were held in the Aquatic Biomechanics Research Laboratory and at the swimming pool of CEFID/UDESC. Force data were acquired through to force plates which were connected to the signal conditioner and A/D convertor ADS2000-IP. The effects of immersion (land, hip level and chest level of immersion), movement cadence (eight sub-maximal cadences and one maximal cadence at each level of immersion) and of body density were analyzed. 35 seconds of stationary running at each analysis situation were acquired, with an interval of one minute between trials. The maximum cadence reached by subjects (Cadmáx) was verified through Fast Fourier Transform (FFT). All curves were exported and analyzed through a processing routine created with the Scilab 4.1.2 software. Descriptive and inferential statistics were used. A predictive model of Fymáx was created through the multiple regression (stepwise) analysis of immersion level, movement cadence and body density. Higher Cadmáx were found during on-land stationary running, followed by hip and chest immersion respectively. Not only level of immersion, but also cadence and body density, showed a significant effect on Fymáx. Although Fymáx values were higher on land regardless of the movement cadence, there was a significant interaction between levels of immersion and cadence: on land, Fymáx increased linearly with increasing cadence; while, at hip and chest immersion, Fymáx increased up to a certain point, where it started to decrease with increasing cadence. This limit point was observed at 130 bpm at chest level of immersion and at 145 bpm when immersed to the hip. Regarding the effect of body density, the results show that less dense subjects present lower values of Fymáx. Two valid predictive models were developed. The first one was for both on-land and water stationary running, being capable of determining 75% of Fymáx variability. The second one was developed exclusively for water stationary running and explicated 69% of Fymáx variability. Although the second model presented a lower determination coefficient, it also showed the lower levels of residue, which indicates that this model is more adequate for Fymáx prediction. The results confirm that the water environment can be used as an alternative for Fymáx reduction during stationary running; however, there is need of controlling the level of immersion, the movement cadence and, to a lesser extent, the body density of subjects. The choice of which cadence to use depends on the immersion level. The presence of a limit on the increasing effect of cadence on Fymáx can be an interesting tool when prescribing stationary running in water. The significant effect of body density on Fymáx suggests a differenced prescription for obese or overweight people. / Este estudo objetivou analisar o pico máximo da componente vertical (Fymáx) da força de reação do solo durante a corrida estacionária em ambiente aquático e terrestre. Os efeitos da imersão (solo, nível de imersão do quadril e nível de imersão do xifóide), da cadência do movimento (oito cadências pré-estabelecidas e uma máxima em cada imersão) e da densidade corporal dos participantes no Fymáx foram analisados. Participaram da pesquisa 32 sujeitos saudáveis, com idade entre 20 e 35 anos. As coletas de dados foram realizadas na piscina e no Laboratório de Pesquisas em Biomecânica Aquática do CEFID/UDESC. Foram utilizadas duas plataformas de força extensométricas conectadas ao sistema de aquisição de dados ADS2000-IP. Foram adquiridos 35 segundos de corrida estacionária em cada situação de análise, com intervalo de um minuto entre as execuções. A máxima cadência alcançada (Cadmáx) em cada imersão foi verificada através da Transformada de Fourier (FFT). O processamento dos dados foi realizado por meio de rotinas criadas no software Scilab 4.1.2 e analisados com a utilização da estatística descritiva e inferencial (p≤0,05). Um modelo de predição para Fymáx a partir da cadência, do nível de imersão e da densidade corporal foi desenvolvido através da regressão múltipla pelo método stepwise. Maiores intensidades de Cadmáx foram encontradas no solo, seguido pelo nível de imersão do quadril e do xifóide respectivamente. Tanto o nível de imersão, bem como a cadência do movimento e a densidade corporal dos sujeitos tiveram efeito significativo sobre Fymáx. Embora os valores de Fymáx tenham se mostrado maiores no solo, seguido pelo quadril, independentemente da cadência utilizada; houve uma interação significativa entre o efeito da imersão e o efeito da cadência do movimento: no solo, quanto maior a cadência, mais intenso foi Fymáx; no entanto, para os níveis do quadril e do xifóide, a intensidade de Fymáx diminuiu quando a corrida estacionária foi realizada em cadências maiores que 130 bpm no nível do xifóide ou maiores que 145 bpm no quadril. Em relação ao efeito da densidade, verificou-se que os sujeitos menos densos apresentaram menor intensidade de Fymáx. Dois modelos válidos de predição de Fymáx foram desenvolvidos. O primeiro foi proposto para a predição na corrida estacionária no solo e no ambiente aquático, sendo capaz de explicar 75% da variação de Fymáx. O segundo foi desenvolvido exclusivamente para o ambiente aquático e foi capaz de determinar 69% da variação de Fymáx. Embora o segundo modelo tenha apresentado um coeficiente de determinação menor, o resíduo envolvido na predição também foi menor, o que o torna mais adequado para uso na prática clínica. Os resultados confirmam que o ambiente aquático pode e deve ser utilizado como uma alternativa para a redução de Fymáx na corrida estacionária; no entanto, o controle da cadência do movimento, do nível de imersão e, em uma menor intensidade, da densidade corporal se faz necessário. Além disso, conclui-se que a escolha da cadência do exercício deve levar em conta os diferente níveis de imersão e que a presença de uma deflexão na curva cadência versus Fymáx pode ser uma ferramenta interessante na prescrição da corrida estacionária no ambiente aquático. O efeito significativo da densidade corporal em Fymáx sugere uma prescrição diferenciada para pessoas com sobrepeso e/ou obesas.
148

Descrição comparativa do padrão angular em bicicleta estacionária, modalidade indoor, chassi fixo e articulado

Pinzon, Cassiano January 2012 (has links)
A bicicleta estacionária articulada é um tipo de equipamento disponibilizado recentemente ao mercado de fitness, consequentemente não explorado em estudos no meio acadêmico científico. Desta forma surgem alguns problemas de pesquisas, desde o fato da instrumentação deste equipamento até a escolha de metodologias e variáveis a serem estudadas para potencializar o seu uso. Este estudo foi realizado com o proposito de descrever as diferenças quanto ao padrão angular da pedalada do ciclista, ou seja, o ângulo do pedal relativo ao pedivela, utilizando-se desta nova bicicleta estacionária de ciclismo indoor, comparando a condição chassi fixo com o articulado. Para a instrumentação, foi acoplado um gerador e um encoder junto a roda de inércia tendo controle das variáveis carga e cadência. Para a medição do ângulo do pedal, os pedais (direito e esquerdo) da bicicleta foram substituídos por pedais instrumentados com potenciômetros, já para o registro do ângulo do pedivela, foi utilizado um sensor eletromagnético, do tipo reed switch. A amostra foi composta por cinco praticantes, todos devidamente adaptados com bicicletas de chassi articulado, submetidas a um protocolo pré-estabelecido, variando condição (fixo e articulado) e posição (pedalando no selim e em pé) com carga e cadência determinada. Embora a amplitude de movimento para ambos os pedais não apresentaram diferenças, em análise, os resultados apontaram que o uso do chassi articulado afeta o padrão angular do pedal durante o ciclo da pedalada, menos acentuado quando utilizou-se a posição sentado no selim, e mais acentuado quando estava-se pedalando em pé. Das posições no pedivela que apresentaram as diferenças no padrão angular durante o uso do chassi articulado, 80% foram na parte produtiva da pedalada (ângulo de 0° a 180°), e o ângulo de 150° concentrou 60% destas ocorrências. Já, tratando-se de forças no pedal, o chassi articulado apresenta evidência de ser mais eficiente do que o chassi fixo. / The stationary articulated bicycle is a type of equipment which is available to the fitness market only recently, and therefore it was not investigated in academic or scientific studies yet. Thus, this fact arises some problems of research, from the fact of instrumentation of this equipment to the choice of methods and variables to be studied to maximize its use. This study was conducted with the purpose to describe the differences in the angular pattern of cyclist pedaling, i.e., the angle on the pedal crank, using this new stationary bicycle of indoor cycling, by comparing the condition of the fixed chassis with the articulated one. For the instrumentation, a generator and an encoder were connected to the wheel of inertia, taking control of the load and cadence variables. To measure the angle of the pedal, the left and right pedals of the bicycle were replaced by pedals which were instrumented with potentiometers. To record the angle of the crank, we used an electromagnetic sensor, the reed switch. The sample consisted of five practitioners, all suitably adapted with articulated frame bicycles, which were subjected to a pre-established protocol, varying the condition (fixed or articulated), and the position (pedaling in the saddle or standing up), with determined load and cadence. The results indicated that the use of articulated frame affects the pattern of the pedal angle during the pedaling cycle, less marked when the sitting position on the saddle was used, and more pronounced when pedaling on the standing up position. About the positions of the crank that showed differences in angle while using the articulated frame: 80% were in the productive part of the pedaling (angle from 0° to 180°), and the angle of 150° concentrated 60% of these incidents. The amplitude of angular movement of the pedal showed no differences between fixed and articulated frame. However, in the case of forces on the pedal, the articulated frame shows evidence of being more efficient than the fixed frame.
149

Relaxação não-colisional em plasmas não-neutros

Teles, Tarcisio Nunes January 2008 (has links)
Neste trabalho um modelo é apresentado que permite-nos prever quantitativamente o estado estacionário atingido por um plasma não-neutro durante um processo de relaxação nãocolisional. Como uma aplicação específica, a teoria é usada para estudar a relaxação de feixes de partículas carregadas na qual, mostra-se que, um feixe inicialmente casado relaxa para a distribuição de Lynden-Bell. No entanto, quando existe um descasamento inicial, o mesmo oscila e ressonâncias paramétricas conduzem-no a uma separação de fases: caroço e halo. A abordagem desenvolvida vale tanto para a densidade como para a distribuição de velocidade no estado final estacionário. / In this work a theoretical framework is presented which allows us to quantitatively predict the final stationary state achieved by a non-neutral plasma during a process of collisionless relaxation. As a specific application, the theory is used to study relaxation of charged-particle beams. It is shown that a fully matched beam relaxes to the Lynden-Bell distribution. However, when a mismatch is present and the beam oscillates, parametric resonances lead to a corehalo phase separation. The approach developed accounts for both the density and the velocity distributions in the final stationary state.
150

Desenvolvimento de fases estacionarias de polaridade intermediaria para cromatografia liquida de alta eficiencia em fase reversa / Development of intermediate polarity stationary phases for reversed phase high performance liquid chromatography

Magalhães, Daniel Rodrigues 19 December 2005 (has links)
Orientador: Carol Hollingworth Collins / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-05T16:30:01Z (GMT). No. of bitstreams: 1 Magalhaes_DanielRodrigues_D.pdf: 3095259 bytes, checksum: 34caab6a50b8a2f3071fca69103ab15f (MD5) Previous issue date: 2005 / Doutorado / Quimica Analitica / Doutor em Ciências

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