Este trabalho trata do estudo e aplicação da técnica de abertura focal sintética (SAFT) na geração de imagens por ultra-som em modo-B com transdutores matriciais lineares, para aplicação em ensaios não destrutivos. Sinais em modo-A são adquiridos e armazenados correspondentes ao meio inspecionado. Implementaram-se duas estratégias de processamento baseadas no método SAFT. A primeira consiste em um elemento central do array emitindo e todos recebendo, resultando em imagens com uma baixa energia acústica envolvida. A outra estratégia considera cada um dos elementos do array emissores e receptores gerando imagens de melhor qualidade, mas requer um maior tempo de processamento. Aplicaram-se técnicas de processamento digital de sinais como: filtragem, extração da envoltória, retificação, compressão logarítmica, interpolação e janelas de ponderação. Arquivos de dados foram gerados com um array de 128 elementos pelos pesquisadores da Universidade de Michigan e disponibilizados no site. Esses foram utilizados para a elaboração e otimização dos algoritmos no MatlabR. As imagens obtidas foram analisadas com relação a alguns parâmetros como a resolução axial e lateral, o contraste e o tempo de processamento. Foi confeccionado, no Laboratório de Ultra-Som da Escola Politécnica da Universidade de São Paulo, transdutor array de 16 elementos. Realizaram-se experimentos, adquirindo-se sinais que foram processados, gerando imagens referentes ao meio inspecionado. / This work deals with the study and application of the synthetic aperture focusing technique (SAFT) for generating ultrasonic images in mode-B with linear array transducers for nondestructive testing applications. Modo-A signals are acquired and stored corresponding to the inspected medium. It was implemented two processing strategies based on SAFT. The first one consists of an array emitting with the central element and receiving with all the elements, resulting in images with a low acoustic energy involved. The second considers each one of the emitting and receiving elements of the array, generating images of better quality but requiring a longer processing time. Digital signal processing techniques were applied such as: filtering, envelope detection, rectification, logarithmic compression, interpolation, and weighting windows. Data were generated with a 128-element array by researchers from the University of Michigan and made available at the institution website. These data were used for elaborating and optimizing the algorithms using MatlabR. The acquired images were analyzed regarding some parameters as axial and lateral resolution, contrast and the processing time. A 16-element array was confectioned in the Ultrasound Laboratory of the School of Engineering at the University of São Paulo. Experiments were conducted and signals were acquired and processed, resulting in images of the inspected medium.

Cette thèse est composée de trois articles qui posent chacun une question sur les discriminations. Le premier article interroge si les habitants de la Seine-Saint-Denis sont statistiquement discriminés sur une violence supposée ; où la pratique d’un sport de combat serait un signal de violence. Le second article regarde si les accents marseillais sont discriminés sur le marché du travail. Le dernier article se demande si les employeurs pourraient utiliser le patronyme et l’adresse des candidats à l’embauche pour faire des corrélations sur leur accent et, s’ils infèrent qu’ils ont l’accent des grands ensembles, de les discriminer sur ce point. La méthode du « testing » est utilisée pour répondre à ces trois questions. Les deux premiers testings amènent à répondre par la négative aux deux premières questions. Concernant la troisième question, même si l’on ne peut pas y répondre, le troisième testing prouve que l’accent des grands ensembles est discriminé. De plus, il démontre que la discrimination sur le patronyme peut mettre dans l’ombre celle sur l’adresse. De façon générale, ce travail permet de mettre en évidence que les employeurs ne prennent pas en compte le sport dans leur pratique d’embauche et que lors de l’élaboration du design d’un testing on doit distinguer les signaux forts des signaux faibles. Il montre aussi que les testings peuvent être utilisés jusqu’au moment où les employeurs contactent les candidats par téléphone et qu’ils engagent des stéréotypes différents selon l’accent qu’ils entendent. Enfin, il propose aux décideurs publics de chercher à d’abord diminuer la discrimination basée sur le patronyme s’ils veulent diminuer la discrimination totale. / This thesis is composed of three articles. Each of them asks one question about discriminations. The first article interrogates if Seine-Saint-Denis inhabitants are statistically discriminated on a supposed violence ; where to do a fighting sport would be a violence signal. The second article investigates if Marseille accents are discriminated in the labor market. The third article asks if employers may use the name and the address as proxies to determine job candidates’ accent and, if they infer he holds a poor area accent, to discriminate on the basis of this accent. I use the correspondence study method to reply to these three questions. The first two correspondence studies lead to conclude to the negative to the first two questions. Concerning the third question, even if we cannot reply to it, the third correspondence study proves that the poor area accent is discriminated. Moreover, it shows that the name discrimination may overcomes the address one.General conclusions are that this thesis indicates employers do not take into account the practiced sport to hire and that to elaborate the design of a correspondence study implies to consider weak and strong signals. It also shows that correspondence studies can be used up to the moment where employers contact job applicants by phone and that they have different stereotypes in mind according to the accent they hear. Finally, it proposes to public policy makers to first decrease the name discrimination if they want to significantly impact the total discrimination.

Este trabalho trata do estudo e aplicação da técnica de abertura focal sintética (SAFT) na geração de imagens por ultra-som em modo-B com transdutores matriciais lineares, para aplicação em ensaios não destrutivos. Sinais em modo-A são adquiridos e armazenados correspondentes ao meio inspecionado. Implementaram-se duas estratégias de processamento baseadas no método SAFT. A primeira consiste em um elemento central do array emitindo e todos recebendo, resultando em imagens com uma baixa energia acústica envolvida. A outra estratégia considera cada um dos elementos do array emissores e receptores gerando imagens de melhor qualidade, mas requer um maior tempo de processamento. Aplicaram-se técnicas de processamento digital de sinais como: filtragem, extração da envoltória, retificação, compressão logarítmica, interpolação e janelas de ponderação. Arquivos de dados foram gerados com um array de 128 elementos pelos pesquisadores da Universidade de Michigan e disponibilizados no site. Esses foram utilizados para a elaboração e otimização dos algoritmos no MatlabR. As imagens obtidas foram analisadas com relação a alguns parâmetros como a resolução axial e lateral, o contraste e o tempo de processamento. Foi confeccionado, no Laboratório de Ultra-Som da Escola Politécnica da Universidade de São Paulo, transdutor array de 16 elementos. Realizaram-se experimentos, adquirindo-se sinais que foram processados, gerando imagens referentes ao meio inspecionado. / This work deals with the study and application of the synthetic aperture focusing technique (SAFT) for generating ultrasonic images in mode-B with linear array transducers for nondestructive testing applications. Modo-A signals are acquired and stored corresponding to the inspected medium. It was implemented two processing strategies based on SAFT. The first one consists of an array emitting with the central element and receiving with all the elements, resulting in images with a low acoustic energy involved. The second considers each one of the emitting and receiving elements of the array, generating images of better quality but requiring a longer processing time. Digital signal processing techniques were applied such as: filtering, envelope detection, rectification, logarithmic compression, interpolation, and weighting windows. Data were generated with a 128-element array by researchers from the University of Michigan and made available at the institution website. These data were used for elaborating and optimizing the algorithms using MatlabR. The acquired images were analyzed regarding some parameters as axial and lateral resolution, contrast and the processing time. A 16-element array was confectioned in the Ultrasound Laboratory of the School of Engineering at the University of São Paulo. Experiments were conducted and signals were acquired and processed, resulting in images of the inspected medium.

Na área de Ensaios Não Destrutivos, o ensaio por eddy current (correntes parasitas) é uma técnica eletromagnética largamente utilizada nas indústrias aeroespacial, nuclear e petroquímica. Esse ensaio detecta descontinuidades superficiais e subsuperficiais, prevenindo acidentes. A técnica phased array surgiu para suprir carências, como o enorme tempo gasto para execução do ensaio em materiais de geometria complexa e falta de registro do ensaio. Essa técnica, já bastante utilizada em outros países, ainda é pouco utilizada no Brasil, por não haver estudos que comprovem a viabilidade econômica, os níveis de detectabilidade de descontinuidades e a confiabilidade dos resultados. Este trabalho tem como objetivo comparar as técnicas do ensaio por Correntes Parasitas convencional com a técnica por phased array, em materiais e peças especificamente utilizados no setor aeronáutico e espacial. Foram selecionadas amostras de materiais e peças, para que pudessem ser aplicadas ambas as técnicas e comparados os resultados. Foi realizado um levantamento bibliográfico das principais normas e especificações utilizadas neste segmento, para verificar a compatibilidade dos métodos. Para atender ao objetivo deste trabalho, foram realizados sete experimentos, variando o material e as técnicas. Após a realização dos ensaios, observou-se uma grande redução de tempo na execução do ensaio, com consequente redução de custos e maior detectabilidade das descontinuidades, com o uso da técnica por phased array. Portanto, baseado nos resultados encontrados, pode-se afirmar que a técnica por phased array pode ser utilizada neste segmento, com vantagens sobre a técnica convencional. / In the area of nondestructive testing, eddy current testing is an electromagnetic technique widely used in aerospace, nuclear and petrochemical industries. This test detects surface and subsurface discontinuities, preventing accidents. Phased array technique has emerged to fill in the gaps, as the enormous time spent implementing the test of large parts or complex geometry and lack of trial registration. This technique, already widely used in others countries, is not used in Brazil, there is no studies proving the economic viability, levels of detectability of discontinuities and reliability of the results. This study aims to compare the conventional technique by eddy current testing with phased array technique, in particular materials and parts used in aeronautics and space sector. Samples of materials and parts were prepared, so that could be applied both techniques and compared the results. A literature survey of the main standards and specifications for this segment was conducted to verify the compatibility of the methods. To meet the objective of this work, seven experiments were performed, varying the material and techniques. After the tests, there was a significant time reduction with the use of phased array technique, costs reduction and increased detectability of discontinuities. Based on the results, it can be said that phased array technique can be used in this segment, with advantages over the conventional technique.

abstract: Cytometry is a method used to measure and collect the physical and chemical characteristics of a population of cells. In modern medical settings, the trend of precision and personalized medicines has imposed a need for rapid point-of-care diagnostic technologies. A rapid cytometric method, which aims at detecting and analyzing cells in direct patient samples, is therefore desirable. This dissertation presents the development of light-scattering-based imaging methods for detecting and analyzing cells and applies the technology in four applications. The first application is tracking phenotypic features of single particles, thereby differentiating bacterial cells from non-living particles in a label-free manner. The second application is a culture-free antimicrobial susceptibility test that rapidly tracks multiple, antimicrobial-induced phenotypic changes of bacterial cells with results obtained within 30 – 90 minutes. The third application is rapid antimicrobial susceptibility testing (AST) of bacterial cell growth directly in-patient urine samples, without a pre-culture step, within 90 min. This technology demonstrated rapid (90 min) detection of Escherichia coli in 24 clinical urine samples with 100% sensitivity and 83% specificity and rapid (90 min) AST in 12 urine samples with 87.5% categorical agreement with two antibiotics, ampicillin and ciprofloxacin. The fourth application is a multi-dimensional imaging cytometry system that integrates multiple light sources from different angles to simultaneously capture time-lapse, forward scattering and side scattering images of blood cells. The system has demonstrated capacity to detect red blood cell agglutination, assess red blood cell lysis, and differentiate red and white blood cells for potential implementation in clinical hematology analyses. These large-volume, light-scattering cytometric technologies can be used and applied in clinical and research settings to study, detect, and analyze cells. These studies developed rapid point-of-care diagnostic and imaging technologies for collectively advancing modern medicine and global health. / Dissertation/Thesis / Doctoral Dissertation Chemistry 2020

Uma das aplicações da análise modal experimental é a avaliação da integridade estrutural. O ensaio dinâmico fornece os valores de freqüência natural, cujas variações podem ser utilizadas para identificar a presença e a magnitude do dano e determinar a rigidez equivalente de peças já fissuradas. Atualmente, as pesquisas sobre o efeito dinâmico nas estruturas civis estão se tornando mais freqüentes. Dentre os vários aspectos de interesse relacionados ao comportamento dinâmico das estruturas de concreto armado, cita-se como relevante a questão da danificação progressiva de seus elementos. Com a evolução da fissuração, existe uma diminuição da freqüência natural e um aumento do amortecimento. Essa variação dos parâmetros permite obter os valores de rigidez equivalente para os diversos estágios de fissuração da peça, o que pode indicar a proximidade da ruptura. Neste trabalho foi avaliada a integridade de elementos estruturais de concreto, discutindo os resultados da análise modal experimental em função do nível de danificação. Foram realizados ensaios em elementos de concreto simples para avaliação do módulo de elasticidade, tanto pelo método estático como pelo método dinâmico, observando a sua variação em função da microfissuração, resistência à compressão e idade do concreto. Os ensaios experimentais foram realizados em corpos-de-prova cilíndricos e prismáticos, sendo os resultados dos ensaios de vibração livre comparados aos resultados obtidos com os ensaios estáticos usuais. Também foram realizados ensaios estáticos e dinâmicos em vigas de concreto armado, de tamanho reduzido, para análise do comportamento de parâmetros dinâmicos ao longo de um processo de danificação. Demonstra-se a viabilidade dos ensaios não-destrutivos dinâmicos para a determinação das propriedades do material e dos elementos de concreto armado, além das vantagens econômicas, facilidade de execução e confiabilidade / Structural integrity assessment may be performed by experimental modal analysis. The dynamic tests provide natural frequencies values whose changes may be used to identify existent damage and to estimate the equivalent stiffness of cracked elements. Nowadays more researches about dynamic effects on civil structures are becoming available. Among all aspects related to the dynamic behaviour of reinforced concrete structures, the progressive damage of their elements is one of great relevance. According to the damage progress, the natural frequencies decrease and the damping factors increase. These dynamic characteristics changes allow getting the equivalent stiffness values for the various degrees of cracking, even indicating the closeness to failure. The objective of this research is to assess the concrete elements integrity and to discuss the results from experimental modal analysis due to different damage levels. There were carried through dynamic and static experiments to evaluate the modulus of elasticity of concrete. It was observed its changes related to concrete micro-cracking, compression strength and age. The experimental testings had been carried through in cylindrical and prismatic specimens. The results obtained from free vibration tests were compared with the ones obtained from the usual static tests. Reinforced concrete beams were also subjected to static and dynamic testings to assess the behavior of the dynamic parameters throughout a damage process. The dynamic non-destructive tests can be used to find out concrete and reinforced beam properties, beyond its economic advantages, easiness to do and trustworthiness

Uma das aplicações da análise modal experimental é a avaliação da integridade estrutural. O ensaio dinâmico fornece os valores de freqüência natural, cujas variações podem ser utilizadas para identificar a presença e a magnitude do dano e determinar a rigidez equivalente de peças já fissuradas. Atualmente, as pesquisas sobre o efeito dinâmico nas estruturas civis estão se tornando mais freqüentes. Dentre os vários aspectos de interesse relacionados ao comportamento dinâmico das estruturas de concreto armado, cita-se como relevante a questão da danificação progressiva de seus elementos. Com a evolução da fissuração, existe uma diminuição da freqüência natural e um aumento do amortecimento. Essa variação dos parâmetros permite obter os valores de rigidez equivalente para os diversos estágios de fissuração da peça, o que pode indicar a proximidade da ruptura. Neste trabalho foi avaliada a integridade de elementos estruturais de concreto, discutindo os resultados da análise modal experimental em função do nível de danificação. Foram realizados ensaios em elementos de concreto simples para avaliação do módulo de elasticidade, tanto pelo método estático como pelo método dinâmico, observando a sua variação em função da microfissuração, resistência à compressão e idade do concreto. Os ensaios experimentais foram realizados em corpos-de-prova cilíndricos e prismáticos, sendo os resultados dos ensaios de vibração livre comparados aos resultados obtidos com os ensaios estáticos usuais. Também foram realizados ensaios estáticos e dinâmicos em vigas de concreto armado, de tamanho reduzido, para análise do comportamento de parâmetros dinâmicos ao longo de um processo de danificação. Demonstra-se a viabilidade dos ensaios não-destrutivos dinâmicos para a determinação das propriedades do material e dos elementos de concreto armado, além das vantagens econômicas, facilidade de execução e confiabilidade / Structural integrity assessment may be performed by experimental modal analysis. The dynamic tests provide natural frequencies values whose changes may be used to identify existent damage and to estimate the equivalent stiffness of cracked elements. Nowadays more researches about dynamic effects on civil structures are becoming available. Among all aspects related to the dynamic behaviour of reinforced concrete structures, the progressive damage of their elements is one of great relevance. According to the damage progress, the natural frequencies decrease and the damping factors increase. These dynamic characteristics changes allow getting the equivalent stiffness values for the various degrees of cracking, even indicating the closeness to failure. The objective of this research is to assess the concrete elements integrity and to discuss the results from experimental modal analysis due to different damage levels. There were carried through dynamic and static experiments to evaluate the modulus of elasticity of concrete. It was observed its changes related to concrete micro-cracking, compression strength and age. The experimental testings had been carried through in cylindrical and prismatic specimens. The results obtained from free vibration tests were compared with the ones obtained from the usual static tests. Reinforced concrete beams were also subjected to static and dynamic testings to assess the behavior of the dynamic parameters throughout a damage process. The dynamic non-destructive tests can be used to find out concrete and reinforced beam properties, beyond its economic advantages, easiness to do and trustworthiness

Ce document présente les analyses expérimentales de deux types de composants aérodynamiques, lubrifiés en air : les butées à feuilles et les paliers à feuilles. Ces éléments constituent une nouvelle génération d'organes de guidages, et gagnent à être implémentés dans des machines tournantes dont les performances sont critiques. En effet, ils permettent d'atteindre des vitesses élevées, sans usure en régime établit, et diminuent la puissance dissipée en comparaison à des solutions fonctionnant avec de l'huile. Ce mémoire est une contribution à l'étude de chacun de ces éléments, dont les niveaux respectifs de maturité technologique ne sont pas similaires. Le palier à feuilles possède une littérature plus riche que la butée, dont aucune analyse expérimentale dynamique n'a été menée jusqu'à présent. Un banc d'essai, destiné à l'étude de butées à feuilles, sous des charges statiques et dynamiques, est conçu. Les caractéristiques de démarrage montrent une augmentation linéaire du couple de démarrage avec la charge statique, une augmentation linéaire du couple en fonctionnement aussi bien avec la charge statique qu'avec la vitesse de rotation, et enfin, une augmentation globale de la vitesse de décollage avec la charge statique. Les essais dynamiques montrent, pour la raideur dynamique, une augmentation non linéaire avec la fréquence d'excitation (entre 150 Hz et 750 Hz) ainsi qu'avec la charge statique appliquée. L'amortissement visqueux équivalent diminue avec la fréquence d'excitation, mais augmente avec la charge statique. Les essais montrent, à charge équivalente, une diminution de la raideur et de l'amortissement avec l'augmentation de la vitesse de rotation. Les facteurs d'amortissements structurels diminuent avec l'augmentation de la fréquence d'excitation, et augmentent avec la charge statique. Afin de se rapprocher d'une architecture de turbomachine, un banc d'essai existant est adapté à l'utilisation de paliers à feuilles. L'étude du comportement de deux rotors rigides (un léger et un lourd) est menée. Celle-ci s'effectue de deux façons : par l'analyse de spectrogrammes enregistrés suivant deux directions du plan de chaque palier, ou bien en étudiant la réponse synchrone à différents balourds. Une confrontation avec deux modèles théoriques est effectuée, en comparant soit la réponse synchrone au balourd dans chaque palier, soit les spectrogrammes. Les balourds sont comparés avec un modèle de rotor rigide linéaire (analyse en petites perturbations) à 4 degrés de libertés, dans lequel les coefficients dynamiques des paliers obtenus grâce au code Foil sont utilisés. les spectrogrammes montrent des vibrations sous-synchrones, qui sont reproduites dans ce mémoire au moyen d'un modèle simplifié de force dynamique. Les résultats expérimentaux actuels montrent les limites des modélisations des paliers à feuilles existantes. Afin d'améliorer la connaissance et la prédiction de ces composants, il est dorénavant nécessaire d'établir un nouveau modèle dynamique, non linéaire, permettant de prédire les réponses synchrones aux balourds ainsi que la richesse sous-synchrone de la signature dynamique d'un rotor supporté par ces paliers. / This document deals with the experimental analyses of two types of air lubricated aerodynamic components: foil journal bearings and foil thrust bearings. These components belong to a new generation of bearings, and are well worth integrating in turbomachinery, which performances are at stakes. Indeed they enable to reach very high speeds without any wear in continuous regime and they diminish energy loss compared to oil bearings. This memoir is a contribution to these two elements, which maturity levels are different.A test rig dedicated to the study of foil thrust bearings under both static and dynamic loads is designed. Start-up characteristics show a linear increase of start-up torque with static load, a linear increase of the fluid film torque with both static load and rotation speed, and an increase of lift-off speed with rotation speed. Dynamical tests show a non linear increase of the stiffness with both excitation frequency (between 150 Hz and 750 Hz) and static load. Equivalent viscous damping decreases with excitation frequency, but increase with static load. Loss factor decreases with excitation frequency and increase with static load.An existing test rig was modified to test foil journal bearings, in a close architecture compared to turbomachines. Two rigid rotors (one light and one heavy) supported by two foil journal bearings were studied. Study is made in two different ways: by the analysis of the displacements spectrograms in two perpendicular directions on each bearing, or the study of the synchronous response at different unbalance masses. A comparison between experimental results and two theoretical models is made. Unbalance responses are compared to a linear rigid rotor model with 4 degrees of freedom, in which the dynamic coefficients of the foil journal bearings are obtained thanks to the Foil algorithm. Spectrograms show sub-synchronous vibrations that are computed thanks to a simplified dynamic force model. Experimental results show the limits in the foil journal bearings theoretical models. In order to improve knowledge and prediction of these components, it is now compulsory to establish a new non-linear dynamical model, enabling to predict both the synchronous unbalance responses and the complexity of the sub-synchronous dynamical signature of a rotor maintained by two foil journal bearings.

International Telemetering Conference Proceedings / October 17-20, 1994 / Town & Country Hotel and Conference Center, San Diego, California / The Aircraft Research and Development Unit (ARDU) of the Royal Australian Air Force (RAAF) is the only agency in Australia that performs the full spectrum of military flight testing and is the new custodian of the instrumented weapons range at Woomera. Receiving early attention will be the upgrade and integration of ARDU's telemetry systems with the meteorological and tracking data acquisition capabilities at Woomera to minimize overhead and data turnaround time. To achieve these goals, maximum modularity, extensibility, and product interoperability is being sought in the proposed architecture of all the systems that will need to cooperate on the forecast test programmes. These goals are also driven by the need to be responsive to a wide variety of tasks which presently include structural flight testing of fighter and training aircraft, weapons systems performance evaluation on a variety of combatant aircraft, and a host of other tasks associated with all fixed and rotary wing aircraft in the Army and Air Force inventory. Of all these tasks however, ARDU sees that responsiveness to future testing of F-111Cs fitted with unique Digital Flight Control Systems along with USAF standard F-111Gs may place the most significant demands on data handling —particularly in regard to providing an avionics bus diagnostic capability when performing Operational Flight Programme (OFP) changes to the mission computers. With the timely assistance and advice of Loral Test & Information Systems, who has long-term experience in supporting USAF F-111 test programmes, ARDU is confident of making wise design decisions that will provide the desired flexibility and, at the same time, minimize life-cycle costs by ensuring compliance with the appropriate telemetry and open systems standards. As well, via cooperative agreements with the USAF, the potential exists to acquire proven software products without needing to fund the development costs already absorbed by the USAF. This paper presents ARDU's perception of future needs, a view by LTIS of how best to meet those needs, and, based on ARDU data, a view of how LTIS' proposal will satisfy the requirement to provide maximum extensibility with minimum life-cycle costs.