A técnica de eco de fótons com luz temporalmente incoerente (EFLI) foi utilizada neste trabalho para a medida do tempo de relaxação transversal T2 do Iodeto de 3-3´-Dietiloxadicarbonocianina (DODCI) como função da temperatura. Nestes experimentos foi utilizado um laser de corante de banda larga, bombeado pelo 2&#176 harmônico de um laser de Nd+3 : YAG Q-switched. Este laser operou com os corantes Kiton Red 620 e rodamina 640, cujos máximos do espectro de emissão estão respectivamente em 598 e 610 nm. O tempo de relaxação T2, que é proporcional ao inverso da largura de linha homogênea, segue uma dependência funcional com a temperatura do tipo T-1,9. Encontramos o valor de T2 entre 0 e 30fs para &#955 = 598nm e entre 30 e 590fs para &#955 = 610nm, no intervalo de temperatura entre 300 e 60k. Os perfis das medidas de EFLI podem ser descritos por um modelo baseado num sistema quântico de dois níveis / The photon echo with incoherent light technique (EFLI) has been used in this work for the measurement of the transverse relaxation time T2 in 3-3´-Dietiloxadicarboncyanine Iodide (DODCI) as a function of the temperature. A broad-band dye laser, pumped by the second harmonic of a Q-switched Nd+3 : YAG laser, was used in this experiment. The laser used Kiton Red 620 and rodamine 640 dyes, whose maxima output power are respectively around 598 and 610nm. The relaxation time T2 , which is inversely proportional to the homogeneous linewidth, depends on the temperature according to a T-1,9 Law. We found the value of T2 ranging from 0 to 30fs at 598nm and from 30 to 590fs at 610nm in the temperature range between 300 and 60K. The EFLI profiles can be described by means of a two-level quantum system model

Para reduzir as perdas humanas e materiais durante as inundações, é possível realizar estudo conciso da previsão de chuva, etapa principal de um sistema de alerta antecipado de inundação. O uso de informações de radar de tempo, quando acopladas a modelos de previsão de precipitação baseados fisicamente, pode contribuir para o monitoramento e previsão de episódios de chuva intensa. Desta forma, a previsão de chuva, baseada no uso de informações de radar, juntamente com um modelo conceitual de previsão hidrometeorológica, foi descrita neste trabalho. Teve-se por objetivo aperfeiçoar as previsões de chuva de curtíssimo prazo (poucos minutos), que acopladas a um modelo chuva-vazão, podem ser usadas em sistemas de alerta antecipado. O modelo hidrometeorológico adotado, que considera uma nuvem hipotética unidimensional vertical, foi inicialmente desenvolvido por Georgakakos e Bras (1984a) e ampliado, neste trabalho. Para tal, adotou-se o uso das informações de Topo dos Ecos para determinação da altura das nuvens e considerou-se que a componente do modelo relativa à massa de água líquida no interior da nuvem corresponde à estimativa do conteúdo de água líquida integrado verticalmente (VIL) efetuada por radar. Para eventos de natureza frontal quente e convectiva, o modelo geralmente antecipou o início do processo de chuva, embora tenha conseguido simular seu comportamento e o instante em que o pico da precipitação ocorreu. Para os eventos frontais frios, o pico simulado registrou atraso. Para episódios de simulação com VIL maior que 3 Kg/\'M POT.2\', a chuva simulada acompanhou o comportamento temporal do VIL, mas com influências das variáveis meteorológicas pressão, temperatura e umidade relativa. As lâminas simuladas tornaram-se entrada para o modelo chuva-vazão do SCS, parcialmente calibrado com algoritmo genético. Para a escala de uma pequena bacia hidrográfica urbana brasileira, com estação fluviométrica experimental, preliminarmente, alguns resultados indicam vazões um pouco inferiores e com atrasos na previsão da vazão máxima. A antecedência proporcionada pelo modelo é de 15 minutos e, apesar da simplicidade, conseguiu-se prever o início do processo de precipitação que gerou inundação do córrego urbano. / To reduce human and material losses during floods it is feasible to concisely study the rainfall forecast as the main part of an early warning system. The use of weather radar information, when linked to physically-based forecast models, can contribute for monitoring and forecasting of intense rainfall episodes. Thus, the rainfall forecast, based on using of radar information along with a conceptual model of hydrometeorological forecast, was outlined in this dissertation. One goal of the study was to improve very short term rainfall forecasts, named as a \'nowcasting\' process throughout few minutes, coupled with a rainfall-runoff generation model to be used in early warning system. The hydrometeorological model, a hypothetical vertical 1-D cloud, was initially developed by Georgakakos and Bras (1984a) and further developed in this study to profit signals from radar tracking control volumes of moisture storage. Either \'Echo Top\' radar information was addressed to determinate the cloud height, and the vertically-integrated liquid (\'VIL\') water mass content inside the cloud, estimated by other radar signal, was considered into the model. On the one hand, during rainfall events of hot and convective front genesis monitored with on-field pluviometers, the model results generally anticipated the beginning of the rain process; however the model was capable of not only simulating well the behavior but also the time-step when rainfall monitored peak occurred. On the other hand, and for cold-front events, the simulating peaks depicted a time delay. For simulation episodes with VIL greater than 3 Kg/\'M POT.2\', the simulated rainfall accompanied the time behavior of VIL, but with influences from weather variables of pressure, temperature and relative humidity. These rainfall depths became inputs of a simple SCS rainfall-runoff model, partially calibrated with genetic algorithms. At the scale of a small brazilian urban river basin with experimental gauging station, some preliminary results modeled streamflows a bit lower than, and with some delay of maximum flow forecasts, observed discharges. The advanced lad time period used by model was of about 15 min and, besides its simplicity, it was quite able to anticipate the beggining of the rainfall process that generated the flood formation at the urban creek.

Made available in DSpace on 2016-04-28T20:39:12Z (GMT). No. of bitstreams: 1 Maria do Socorro Miranda Prado.pdf: 1268099 bytes, checksum: 50298c8a1310dcc5f8c995bd06f24557 (MD5) Previous issue date: 2016-02-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The present research aimed at understanding the Philomena s route, the protagonist of the film with the same name, and her relation with many aspects of Echo Myth. The applied qualitative method fit the model of Penafria (2009) for analyzing film scenes. After the selection of images to be evaluated and taking into consideration the obtained literature, the film was divided in three moments, which express the Philomena s experiences and their relation with Echo aspects and Echo and Narcissus s relationship. The analysis suggests that Philomena, who, at the beginning of the film, had a unilateral identification with Echo, develops an opposing polarity (Narcissus) going beyond the pure Echo s dynamic. The results led to an analysis of the women s experience stuck in this dynamic, suggesting them new possibilities for their live / A presente pesquisa buscou compreender a trajetória de Philomena, protagonista do filme que leva o mesmo nome, e sua relação com os aspectos do mito de Eco. Foi utilizado o método qualitativo, adaptando-se o modelo de Penafria (2009) para análise das cenas fílmicas. Após a escolha das imagens a serem analisadas e tendo em vista a literatura levantada, o filme foi dividido em três momentos que expressam as vivências de Philomena e sua correlação com aspectos de Eco e do relacionamento de Eco e Narciso. A análise sugere que Philomena, a qual se identificara unilateralmente com Eco, no início do filme, consegue desenvolver a polaridade oposta (Narciso), tramitando além da dinâmica puramente ecoísta. Os resultados ampliaram a análise do filme à vivência de mulheres presas nessa dinâmica, sugerindo-lhes novas possibilidades em sua existência

Este trabalho tem dois propósitos principais. O primeiro compreende o estudo de um equipamento transceptor para viabilizar a transmissão digital de dados duplex a dois fins na malha telefônica comercial instalada. Um estudo inicial da linha de assinante e dos principais métodos de transmissão duplex e realizado. O método de cancelamento de eco e sugerido por conferir ao transceptor melhor desempenho. O transceptor tem a sua estrutura abordada e definida. Além do cancelador, todos os demais circuitos, julgados pelo autor como importantes, são analisados. Dentre os principais estão o codificador 2B1Q, os equalizadores adaptativos e a referencia adaptativa. O segundo propósito compreende o estudo de uma arquitetura capaz de implementar o cancelador do transceptor e sua especificação e simulação. Inicialmente, junto a proposta do equipamento, tipos de canceladores, formas de cancelamento e demais características relacionadas são abordadas. O algoritmo utilizado para a adaptação dos coeficientes e exposto, e, através de simulações, validado. Os problemas decorrentes do use de palavra finita em sistemas digitais sac. considerados. Os procedimentos da operação de cancelamento são especificados e as tarefas distribuídas. Após, finalizando este trabalho, propõe-se a parte operativa, composta por dois processadores, por um banco de registradores e por uma interface de entrada e saída. A arquitetura e descrita em linguagem HDC de descrição de hardware e apos simulada funcionalmente para validação das funções pretendidas. A parte de controle, parcialmente descrita também em HDC, tem algumas características comentadas . / This work has two main goals. The first one is the study of a transceiver equipment to allow two-wire duplex data digital transmission over the existing telephonic network. An initial study of the subscriber line and of the main duplex transmission methods is done. The echo cancellation method is suggested since higher performance transceiver may be obtained. The structure of the transceiver is considered and defined. Besides the echo canceller, all the others circuits deemed important by the author are analysed. The second goal comprehends the study of an architecture capable of implementing the transceiver echo canceller, and its specification and simulation. Initially, gearing to the equipment proposal, the type of cancellers, ways of cancelling and other related characteristics are approached. The algorithm used for the adaptation of coefficients is exposed and validated through simulations. The problems due to the use of finite word length in digital systems are considered. The cancelling operation procedures are specified and the different tasks are distributed. Finally, at the end of this work, the data path, composed of two processors, of a register bank and of an I/O interface, is proposed. The architecture is described in the HDC hardware description language, and later it is simulated for validation of the proposed functions. The control path, partially described in HDC also, has some of its characteristics addressed.

Há um grande interesse hoje em desenvolver terminais viva-voz que permitam aos participantes de uma conversa à distância contarem com um bom grau de naturalidade e inteligibilidade. O objetivo deste trabalho é apresentar solução para dois impedimentos que surgem quando se deseja projetar um terminal viva-voz para ser utilizado em automóveis: o eco acústico resultante do acoplamento entre microfone e alto-falante do terminal; e o ruído ambiente produzido por exemplo pelo vento, pneus e motor do veículo. A solução proposta envolve o uso de filtros adaptativos e alterações no espectro do sinal de voz para minimizar os problemas mencionados. Os aspectos teóricos são abordados de forma breve, sem deixar no entanto que nenhum detalhe importante fique de fora. Uma implementação prática e eficiente em processador digital de sinais é um dos destaques do trabalho. / There is currently great motivation in developing hands-free devices which offer users, engaged in a telephone conversation, a good level of naturalness and intelligibility. In this work, the goal is to present a solution for two well-known problems that occur when designing a hands-free device for use in automobile environments: (1) the acoustic echo coupling between microphone and speaker, and (2) the background noise generated for example by wind, tires and vehicle engine. The proposed solution includes adaptive filtering techniques and modifications in the speech signal spectrum, in order to minimize the two problems above. Theoretical issues are briefly analyzed, however the author believes no relevant detail is kept out. Highlighted in the report is a practical and efficient implementation of the algorithms in a modern digital signal processor.

<p>A channel board was designed for a DRFM circuit. The DRFM is implemented in a Virtex-4 FPGA from Xilinx. In the future a similar channel board is intended to be used for target echo generation in ELSI which is an electronic warfare simulator at Saab Bofors Dynamics in Linköping.</p><p>Besides the DRFM circuit the channel board consists of analog-to-digital converters, digital-to-analog converters, Ethernet plug-in board with a microcontroller, voltage regulators, FPGA configuration memory, voltage amplifiers, current amplifiers, oscillator, buffers/drivers and bus transceivers. The sample rate is 200 MHz and LVDS signalling standard is used between the DRFM circuit and the converters.</p><p>The channel board has a JTAG interface which enables in-system programming of the FPGA. This implies that the DRFM can easily be redesigned. An external computer can manage the channel board via Ethernet. Software was developed for the microcontroller on the channel board and for the external computer. The function of the channel board is heavily dependent on the DRFM circuit.</p><p>The channel board design resulted in the assembly of a prototype circuit board. Measurements were performed in a lab and the channel board was approved to be integrated in ELSI for further tests.</p>

Magnetic resonance imaging is an essential tool for assessing soft tissues. The desire for increased signal-to-noise and improved tissue contrast has spurred development of imaging systems operating at magnetic fields exceeding 3.0 Tesla (T). Unfortunately, traditional imaging methods are of limited utility on these systems. Novel imaging methods are required to exploit the potential of high field systems and enable innovative clinical studies. This thesis presents methodological advances for human brain imaging at 4.7 T. These methods are applied to assess sub-cortical gray matter in multiple sclerosis (MS) patients. Safety concerns regarding energy deposition in the patient precludes the use of traditional fast spin echo (FSE) imaging at 4.7 T. Reduced and variable refocusing angles were employed to effectively moderate this energy deposition while maintaining high signal levels; an assortment of time-efficient FSE images are presented. Contrast changes were observed at low angles, but images maintained a clinically useful appearance. Heterogeneous transmit fields hinder the measurement of transverse relaxation times. A post-processing technique was developed to model the salient signal behaviour and enable accurate transverse relaxometry. This method is robust to transmit variations observed at 4.7 T and improves multislice imaging efficiency. Gradient echo sequences can exploit the magnetic susceptibility difference between tissues to enhance contrast, but are corrupted near air/tissue interfaces. A correction method was developed and employed to reliably produce a multitude of quantitative and qualitative image sets. Using these techniques, transverse relaxation times and susceptibility field shifts were measured in sub-cortical nuclei of relapsing-remitting MS patients. Abnormalities in the globus pallidus and pulvinar nucleus were observed in all quantitative methods; most other regions differed on one or more measures. Correlations with disease duration were not observed, reaffirming that the disease process commences prior to symptom onset. The methods presented in this thesis enable efficient qualitative and quantitative imaging at high field strength. Unique challenges, notably patient safety and field variability, were overcome via sequence implementation and data processing. These techniques enable visualization and measurement of unique contrast mechanisms, which reveal insight into neurodegenerative diseases, including widespread sub-cortical gray matter damage in MS.

La réalisation d'une mémoire quantique pour la lumière met en jeu les aspects les plus fondamentaux de l'interaction matière-rayonnement. Pour capturer l'information quantique portée par la lumière, le matériau doit être capable de se maintenir dans un état de superposition quantique. Le temps de stockage est limité par la durée de vie de cet état, caractérisée par le temps de cohérence. Les premières expériences ont été réalisées dans des vapeurs atomiques froides, bien connues. Plus récemment, les ions de terres rares en matrice cristalline (REIC) ont attiré l'attention par leurs long temps de cohérence, associés à de larges bandes passantes d'interaction. Pour exploiter ces bonnes propriétés, des protocoles spécifiques ont été proposés. Nous nous sommes tournés vers un dérivé prometteur de l'écho de photon, le Peigne Atomique de Fréquences (AFC, proposé en 2008), fondé sur la transmission du champ incident à travers un profil d'absorption spectralement périodique. Les premiers chapitres de ce manuscrit présentent ce protocole et les travaux effectués durant cette thèse pour en améliorer l'efficacité (i.e. la probabilité de capter et de restituer l'information incidente), en augmenter la bande passante et la capacité de multiplexage et en mesurer le bruit. Les chapitres suivants présentent un nouveau protocole, proposé dans notre groupe durant cette thèse, et baptisé ROSE (Revival Of Silenced Echo). Ce protocole, très proche de l'écho de photon, a été démontré et caractérisé expérimentalement. Il semble très prometteur en termes d'efficacité, de bande passante et de bruit.

The thesis deals partly with methodology including construction of hardware and new pulse sequences in the field of electrophoretic NMR, and partly with practical use of ENMR and diffusion NMR in the investigation of charged colloidal systems. Several sources of artefacts are investigated, including gas production at the electrodes, electroosmosis and Joule heating effects that can cause convection. The electrophoretic double stimulated-echo pulse sequence is introduced to suppress these artefacts and to increase the feasible measuring range to higher electric fields and conductivities. The interaction between the non-ionic polymer poly(ethylene oxide) PEO and differently charged surfactants is investigated using the above mentioned methods. The investigated surfactants are the anionic sodium dodecyl sulphate (SDS) and potassium laurate (KC12), the cationic dodecyltrimethylammonium bromide (CTAB) and the non-ionic octyl β-D-glucoside. ENMR is also used to investigate two different mixed micelle systems, with SDS as the charged surfactant component and dodecyl malono-bis-N-methylglucamide (C12BNMG) respectively tetra(ethylene oxide) dodecyl ether (C12EO4) as the nonionic surfactant component. A method to calculate the degree of counter-ion dissociation, αdissociation, as a function of composition is demonstrated. Finally diffusion NMR is used to compare transport dynamics in gel electrolyte systems based on two differently grafted polymers; one amphiphilic system containing polymethacrylate grafted partly with polyethylene oxide and partly with fluorocarbons and the corresponding nonamphiphilic system grafted with only polyethylene oxide. Both systems contain the electrolyte lithium bis(trifluoromethylsulfonyl) imide salt dissolved in γ-butyrolactone. The results show that the system based on the amphiphilic polymer has better transport dynamics and therefore is more suited as material for battery

The work of my MFA thesis exhibition comes directly out of the physical processes that constitute my studio practice. It is work that embodies the labour of my hands and the decisions that guided them in their struggle with unfamiliar materials. Drawing inspiration from subjects as diverse as physics and fiction to create a sculptural arrangement, the work is intended to engage with its audience in an active way through acoustic appropriation and physical presence. As an artist, I set up an environment to be explored, establishing boundaries and also possibilities.