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Medidas de correlação angular perturbada diferencial no tempo - TDPAC - foram efetuadas com um sistema de detetores de HPGe com o objetivo de ampliar o conjunto de nuclídeos utilizáveis como sondas de prova de campo magnético e de gradiente de campo elétrico na matéria. A análise dos espectros obtidos considera a convolução angular de ordem superior a dois, o que está fora do escopo do procedimento convencional quando se utiliza o arranjo experimental padrão. O algoritmo é baseado no método dos mínimos quadrados e considera rigorosamente as incertezas estatísticas dos dados. O programa de cálculo implementado é orientado a objetos, que representam as estruturas matemáticas envolvidas na redução dos dados pelo método dos mínimos quadrados e os sistemas físicos característicos do experimento. Os detetores semicondutores mostraram-se inadequados ao estudo de materiais por TDPAC nas condições experimentais disponíveis. O método de análise proposto aqui foi aplicado à redução dos espectros obtidos em outros laboratórios, que utilizam cintiladores rápidos, resultando na determinação de parâmetros associados à estrutura cristalina para os quais a análise convencional não é sensível, em particulas dos coeficientes de atenuação temporal da correlação para cada uma das freqüências de oscilação. Esta metodologia permite calcular corretamente as incertezas nos parâmetros, notadamente nas frações de ocupação de diferentes sítios pela sonda de prova. / Time dependent perturbed angular correlation TDPAC measurements were performed with a HPGe detector array aiming to increase the set of nuclides usable as magnetic field and electric field gradient probes in matter. The analysis of the obtained spectra takes into account the convolution of the perturbation function with the detector time response and angular correlation coefficients of order greater than two, which is not in scope of the conventional procedure. The algorithm is based on the least-squares method and considers rigorously the data statistical uncertainties. The implanted computer code is built on objects representing the mathematical entities used in data reduction by the least-squares method and the physical components of the experiment. The semiconductor detectors were found unsuitable for material study through TDPAC in the available experimental conditions. The analysis method proposed here was applied to the reduction of spectra obtained by other Laboratories that use fast scintillators, giving crystalline structure related parameters which cannot be determined in the conventional analysis, particularly correlation time attenuation parameters for each oscillation frequency. The uncertainties in the fitted parameters are correctly calculated by this method notably in the site probe occupation fractions.

Orientador: Carola Dobrigkeit Chinellato / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin / Made available in DSpace on 2018-08-22T13:08:19Z (GMT). No. of bitstreams: 1 Castilho_CamileMendes_M.pdf: 4872331 bytes, checksum: 59af4c2607b071fd467957e83946bcf8 (MD5) Previous issue date: 2013 / Resumo: Duas questões importantes no estudo da física de raios cósmicos são quais são as fontes astrofísicas dessas partículas e como é o campo magnético por elas atravessado. O Observatório Pierre Auger, localizado na província de Mendoza, na Argentina, é um experimento que tem como objetivo estudar raios cósmicos de altas energias (superior a 1 EeV). Entre os objetivos do observatório, está buscar possíveis fontes desses raios cósmicos e estudar o campo magnético por eles atravessado. Considerando que partículas ultra-energéticas sofrem deflexões em campos magnéticos que são inversamente proporcionais _as suas energias, espera-se que aquelas provenientes de uma mesma fonte cheguem á Terra com suas direções alinhadas sobre a esfera celeste e com desvios angulares satisfazendo essa dependência com a energia. Um grupo de raios cósmicos com suas direções e energias satisfazendo essas características é chamado de multipleto. Nesta dissertação, foram analisados 2196 raios cósmicos com energias acima de 20 EeV, detectados pelo Observatório Pierre Auger entre 1o de janeiro de 2004 e 22 de novembro de 2012, a _m de realizar uma busca por multipletos. Para encontrar estes multipletos, foi utilizado o Método da _Arvore de Extensão Mínima. Este método é utilizado para separar o conjunto de raios cósmicos em subconjuntos. Uma vez encontrados esses subconjuntos, foi verificado se as direções dos raios cósmicos do subconjunto satisfazem a correlação esperada entre as suas direções e os inversos de suas energias. Para isso foi calculado o coeficiente de correlação e a dispersão angular nas coordenadas dos raios cósmicos de cada subconjunto em um plano tangente _a esfera celeste no ponto correspondente _a direção média. Se o coeficiente de correlação for superior a um valor mínimo e a dispersão angular for menor do que um valor máximo pré-estabelecidos, o multipleto em questão é considerado um multipleto correlacionado. Após identificarmos estes multipletos, foi possível encontrar as posições das possíveis fontes dos raios cósmicos que o compõem e obter informação sobre o poder de deflexão do campo magnético por eles atravessado nas direções das respectivas fontes. Para o período em questão foram encontrados três multipletos correlacionados com um número de eventos igual ou superior a doze. Para estes três multipletos foram procuradas posições de possíveis fontes. Realizando uma comparação entre as posições encontradas e um catalogo de objetos astrofísicos, foram encontrados objetos próximos ás direções das fontes encontradas / Abstract: Two important questions in the study of ultra-high-energy cosmic rays are related to the astrophysical sources of these particles and the characteristics of the magnetic field they have traversed in their way from the sources to Earth. The Pierre Auger Observatory was designed and built in Argentina in order to address these and other questions about ultra-high energy cosmic rays. Its design goals included being able to measure ultra-high energy cosmic rays (above 1 EeV) with unprecedented statistics. Considering that the trajectories of ultra-high energy particles are defected by the magnetic fields traversed and that the defection is inversely proportional to their energies, it can be expected that particles having different energies and coming from a single source will arrive at Earth with their directions aligned on the celestial sphere and with angular deviations satisfying that dependence with the energy. A group of cosmic rays with their directions and energies satisfying those characteristics is called a multiplet. In this work, we search for multiplets in a data sample of 2196 cosmic rays with energies above 20 EeV recorded by the Pierre Auger Observatory between 1st January 2004 and 22nd November 2012. We applied the method of the minimum spanning tree to separate the whole data set into subsets and then analyzed the subsets, checking whether the directions of the cosmic rays in each subset satisfy the expected correlation with the inverse of their energies. After identifying multiplets which satisfy the correlation, it is possible to find theposition of the sources of the cosmic rays and estimate the defection power of the magnetic field these particles must have traversed in the corresponding directions of the sources. In the period covered by our analysis we have found three multiplets with twelve or more events. For each multiplet we have found the direction of the possible source and the defection power of the magnetic field and looked for nearby astrophysical objects in a catalog / Mestrado / Física / Mestra em Física

Made available in DSpace on 2014-08-20T14:07:36Z (GMT). No. of bitstreams: 1 Dissertacao__Marilia_ W_ Marques.pdf: 521791 bytes, checksum: 960876c449dcc0e6427e3c297bd7b474 (MD5) Previous issue date: 2008-09-05 / The present work purposes to study the fungus Pseudocercospora griseola (Sacc) Crous & U. Braun, causal agent of angular leaf spot on common bean, to evaluate the incidence and severity in produced beans plants from seeds proceeding from pod with different levels of disease, as well as, to verify the effect in the physiological and sanitary quality of the produced seeds. For the development of the experiment, beans plants have been collected with high incidence of angular leaf spot, natural infestation the field. From the collected material it was elaborated a diagrammatic scales varying of 1 the 5, corresponding each note to a severity level on the physical structure of the pod. Parallel experiment was carried out, evaluating symptoms of angular spot in different places of the seed: hilum and coat. The tests carried through in the deriving seeds of the respective treatments had been: tests of germination (TPG), accelerated aging (EA), test of humidity and health. The results had shown that the incidence and the severity of angular leaf spot on common bean had been differed statistical between itself, where the levels of scale 1 and 5 had presented with minor and greater degree of incidence and severity of P. griseola, respectively. Whereas the seeds with symptoms in hilum and in the coat have presented resultes similar to the incidence and severity of the causal agent. The correlation enters the severity of pod and the severity of the disease in the plants was significant. There wasn´t statistical differences between the test of accelerated aging in the tested treatments, resulting a variation of 82-88% of normal seedlings. In the test of germination, treatment 5 differing statistical from the others treatments. In the sanitary analysis the fungus of storage increase incidence to the measure that increased the level of severity of the treatments. It was concluded in this work that pod with 60 % of symptoms of angular leaf spot have the capacity to intervene in the germination of the beans seeds and and that bigger levels of severity of the string beans cause a bigger development of the disease in field. / O presente trabalho teve por finalidade propor um estudo sobre o fungo Pseudocercospora griseola (Sacc) Crous & U. Braun, agente causal da mancha angular, através da avaliação da incidência e severidade em plantas de feijão produzidas a partir de sementes provenientes de vagens com diferentes níveis de severidade da doença, assim como verificar o efeito sobre a qualidade fisiológica e sanitária das sementes produzidas. Para a realização experimental foram coletadas plantas de feijão com alta incidência de mancha angular, infestação natural. A partir do material coletado procedeu-se separação das vagens a partir de uma escala diagramática variando de 1 a 5, correspondendo cada nota a um nível de severidade sobre a superfície da vagem. Experimento paralelo foi realizado, avaliando sintomas de mancha angular em diferentes locais da semente: hilo e tegumento. Os testes realizados nas sementes oriundas dos respectivos tratamentos foram: teste padrão de germinação (TPG), teste de envelhecimento acelerado (EA), determinação do teor de água e analise sanitária. Os resultados mostraram que a incidência e a severidade da mancha angular nas plantas de feijão diferiram-se estatisticamente entre si, onde os níveis da escala 1 e 5 apresentaram-se com menor e maior grau de incidência e severidade de P. griseola, respectivamente. As sementes com sintomas no hilo e sementes com lesões tegumentares apresentaram resultados semelhantes quanto à incidência e severidade do agente causal. A correlação entre a severidade da vagem e a severidade da doença nas plantas foi significativa. Quanto ao teste de envelhecimento acelerado, os tratamentos não diferiram estatisticamente entre si, resultando numa variação de 82 a 88% de plântulas normais. No teste padrão de germinação, o tratamento 5 diferiu estatisticamente dos demais tratamentos. Na análise sanitária, os gêneros fúngicos relacionados a armazenamento apresentaram maior incidência à medida que ocorreu aumento no nível de severidade dos tratamentos. Os resultados permitiram concluir que vagens com 60% de sintomas de mancha angular apresentam a capacidade de interferir no potencial germinativo das sementes de feijão e que maiores níveis de severidade das vagens ocasionam um maior desenvolvimento da doença em campo.

De nombreux efforts fournis sur l’avancement de la technologie de dépôt afin de répondre au besoin des utilisateurs des filtres interférentiels ont donné la naissance à la nouvelle génération des composants optiques. Les progrès techniques permettent de fabriquer les filtres avec la structure particulièrement complexe et atteindre les performances spectrales remarquables, mais aussi soulèvent de nouveaux problèmes au niveau de la diffusion. Les indicatrices de diffusion de ces filtres présentent les variations extrêmement rapides en fonction de l’angle de reprise et de la longueur d’onde, ce qui amoindrit sérieusement les performances des composants. Il est donc d’essentiel d’être capable de caractériser la diffusion lumineuse angulairement et spectralement résolue. L’objectif de cette thèse a alors été de développer l’outil expérimental, déduit pour la métrologie fine de la réponse spectrale et de la diffusion lumineuse. Le travail réalisé a donné naissance au banc SALSA (pour Spectral and Angular Light Scattering characterization Apparatus), un nouveau diffusomètre spectralement et angulairement résolu. Grâce au banc SALSA nous pouvons effectuer les mesures de diffusion sur large gamme spectrale [400 nm -1000 nm] avec la dynamique de 8 décades et la précision meilleure que 1%. Par ailleurs, le banc peut être utilisé pour la mesure de la transmission avec la dynamique de 12 décades, ce qui est performance unique sur l’échèle mondiale. / Due to market demand and technical progresses, a new generation of optical components requires much more sophisticated structures with a great number of layers. These complex structures enable to achieve severe optical performances but, at the same time, enhance light scattering processes. For these reasons, it is essential to develop a metrological tool which provides an accurate quantification of the spectral and angular behavior of scattering losses, with sufficient angular and spectral resolution. In order to face this issue, new investigations were performed during this PhD thesis and led to the development of the new scatterometer SALSA (Spectral and Angular Light Scattering characterization Apparatus). The use of both a broad-band source and a tunable filter allows to accurately select the illumination wavelength and the spectral bandwidth on the whole spectral range of CCD detectivity. Set-up SALSA allows us to perform the measurements of scattering losses on a wide spectral range (400-1000 nm), with high dynamics (>8 decades), high accuracy and low detectivity (a few 10-8 sr-1). Moreover, with set-up SALSA we are able to measure the transmission of interferential filters on the same spectral range, with high accuracy (1%) and a high dynamic (>10 decades, which is a unique performance).

Les mécanismes physiques de la perte de masse des étoiles évoluées sont encore largement inconnus. Ce processus essentiel est pourtant le moteur principal de l'évolution chimique du milieu interstellaire. Pour les supergéantes rouges (SGR), le déclenchement de l'éjection de la matière et les mécanismes de condensation de la poussière demeurent mal compris. La façon dont les géantes rouges parviennent à former des nébuleuses planétaires non-Sphériques est aussi inconnue. Au cours de ma thèse j'ai étudié des étoiles évoluées grâce à des techniques de haute résolution angulaire permettant de détailler leur surface et leur environnement proche où se trouve l'origine de la perte de masse. À partir d'observations interférométriques en infrarouge (IR), j'ai caractérisé l'enveloppe de vapeur d'eau et de monoxyde de carbone de la SGR Bételgeuse. J'ai également suivi l'évolution d'un point chaud à sa surface et analysé la structure de sa convection ainsi que celle d'Antarès (une autre SGR très proche) grâce à des simulations hydrodynamiques radiatives. L'imagerie à la limite de diffraction (optique adaptative en IR, télescope spatial en ultraviolet) m'a permis d'étudier l'évolution des inhomogénéités de l'enveloppe circumstellaire de Bételgeuse et découvrir un disque circumstellaire autour de L2 Puppis, une étoile de la branche asymptotique des géantes. Ces observations multi-Longueurs d'onde, répétées à plusieurs époques, m'ont permis d'initier un suivi temporel et d'apporter des informations sur la dynamique en jeu. Renouvelé sur un plus grand échantillon d'étoiles dans les années à venir, ce programme permettra de mieux appréhender la perte de masse des étoiles évoluées. / Mass loss of evolved stars is still largely mysterious, despite its importance as the main evolution engine for the chemical composition of the interstellar medium. For red supergiants (RSG), the triggering of the outflow and the mechanism of dust condensation remain unknown. Concerning red giant stars, we still do not know how their mass loss is able to form a bipolar planetary nebula. During my PhD thesis, I observed evolved stars with high angular resolution techniques. They allowed us to study the surface and the close environment of these stars, from where mass loss originates. With near-Infrared interferometric observations, I characterized the water vapor and carbon monoxide envelope of the nearby RSG Betelgeuse. I also monitored a hot spot on its surface and analyzed the structure of its convection, as well as that of Antares (another very nearby supergiant) thanks to radiative hydrodynamical simulations. Diffraction-Limited imaging techniques (near-Infrared adaptive optics, ultraviolet space telescope) allowed me to observe the evolution of inhomogeneities in the circumstellar envelope of Betelgeuse and to discover a circumstellar disk around L2 Puppis, an asymptotic giant branch star. These multi-Scale and multi-Wavelength observations obtained at several epochs allowed us to monitor the evolution of the structures and to derive information on the dynamics of the stellar environment. With a wider stellar sample expected in the next few years, this observing program will allow a better understanding of the mass loss of evolved stars.

Future fifth generation (5G) cellular networks have to cope with the expected ten-fold increase in mobile data traffic between 2015 and 2021. To achieve this goal, new technologies are being considered, including massive multiple-input multiple-output (MIMO) systems and millimeter-wave (mmWave) communications. Massive MIMO involves the use of large antenna array sizes at the base station, while mmWave communications employ frequencies between 30 and 300 GHz. In this thesis we study the impact of these technologies on the performance of channel estimators. Our results show that the characteristics of the propagation channel at mmWave frequencies improve the channel estimation performance in comparison with current, low frequency-based, cellular networks. Furthermore, we demonstrate the existence of an optimal angular spread of the multipath clusters, which can be used to maximize the capacity of mmWave networks. We also propose efficient noise variance estimators, which can be employed as an input to existing channel estimators.