Yes / This paper presents a planar multi-circular loop antenna with a wide impedance bandwidth for next generation mm-wave systems. The proposed antenna comprises three circular rings with a partial ground plane with a square slot. The resonating structure is designed on a 0.254 mm thin RO5880 substrate with a relative permittivity of 2.3. The single element of the proposed design showed a resonance response from 26.5 to 41 GHz, with a peak gain of 4 dBi and radiation efficiency of 96%. The proposed multicircular ring antenna element is transformed into a four-element array system. The array size is kept at 18.25 × 12.5 × 0.254 mm3 with a peak gain of 11 dBi. The antenna array is fabricated and measured using the in-house facility. The simulated and measured results are well agreed upon and are found to be suitable for mm-wave communication systems.

Yes / Steel concrete composite beams have been increasingly used in practice due to their advantages with respect to their structural features and constructability. However, in conventional composite beam systems composite action is applied via shear connectors welded at the top flange of the down-stand steel beam and embedded in the concrete slabs, making it less favourable for the beam system to be disassembled and reused. This paper presents a numerical study of a new composite beam system consisting of a cellular steel beam, metal deck flooring and demountable shear connectors. According to the experimental study, this composite beam system made the demounting, reassembly, and member reuse possible, and did not compromise the loading capacity. In the numerical study presented in the paper, a finite element model was developed and validated against the results obtained from the previous experimental study. The parametric study further examined the effects of concrete strength, shear connector arrangements and asymmetry ratios of steel beam section to the load capacity of the composite beam system. The analysis and comparison provided a deeper insight into the behaviour of this type of shear connector. Through this numerical study, the structural merits of the composite beam system using demountable shear connectors were highlighted. Finally, the mid-span plastic moment of the composite beam was predicted using the direction method provided in SCI publications and compared with the moment–deflection relationship obtained from FE modelling. / The research leading to these results is part of a joint project of the University of Bradford, the University of Luxemburg, the Technology University of Delft, the Steel Construction Institute, Tata Steel, Lindab S. A., BmS and AEC3 Ltd. The authors gratefully acknowledge the funding received from the European Commission: Research Fund for Coal and Steel (RFCS-2015, RPJ, 710040). In addition, deep appreciation to Mr. Stephen Robinson for his work done in the laboratory.

This thesis covers nanofabrication of central stops for application in soft X-ray imaging using electron-beam lithography for pattern definition. Central stops are small scale optical components used in combination with an order sorting aperture to eliminate the higher order and zeroth order of light after diffraction from a Fresnel zone plate. The main objectives of this study were to produce central stops with the desired parameters and to obtain an understanding of the nanofabrication process. A challenge which was encountered during the fabrication of the central stops was uncertainties in electroplating time, resulting in multiple plating rounds and in turn impacting the quality of the nanostructures. Another challenge which presented itself was that the structures disappeared on the chip with an uneven resist layer, suggesting that the resist layer’s smoothness is important. A key consideration when fabricating structures on this small scale is therefore to ensure the smoothness of the resist layer. Despite these challenges, one chip was successfully fabricated and could likely be used in the optical system for the SoftiMAX beamline, a beamline used for X-ray imaging at MAX IV, a fourth generation synchrotron radiation facility in Lund. In summary, recommendations for future replications and research would be to use chips with evenly coated resist, to make sure to only electroplate once and, if working with similar structures and parameters, to electroplate for a longer time than calculations suggest.

Antenna arrays offer notable superiority over a single antenna element. By weighting the signals before combining them, antenna arrays offer several enhanced features such as beam steering or beam switching without physically moving the aperture. While in general the array platform can take any given shape, cylindrical arrays offer many advantages compared to linear and planar arrays due to their azimuthal symmetry, and as such find numerous applications in radar, sonar, etc.. This research proposes a Wi-Fi band cylindrical switched beam array that is capable of full azimuthal beam switching for direction finding applications. Six microstrip patch antennas are arranged in a hexagonal platform to create a cylindrical array. The antenna beam is switched electronically using a SP6T RF switch providing azimuthal coverage with 60-degree resolution. Multiple antennas and arrays were designed, analyzed, and fabricated. The devices and the full array system were measured, and their RF performance was characterized. The experimental results validate the feasibility and practicality of the proposed design, and demonstrate a high-speed array platform for direction finding that can be used for search and rescue operations in emergency situations.

This dissertation reports a sensitive single beam experimental technique for measuring nonlinear refraction and nonlinear absorption in a wide variety of materials. The experimental setup is described and a comprehensive theoretical analysis including cases where nonlinear refraction and nonlinear absorption are also presented.

No description available.

Neste trabalho estudou-se as propriedades obtidas em juntas soldadas pelo processo de soldagem a laser do tipo estado sólido de onda contínua guiado por fibra, e os resultados foram comparados com juntas soldadas pelo processo feixe de elétrons. O material utilizado foi o aço maraging 350 - ASTM A 538 Grade C. As soldas realizadas com o processo feixe de elétrons possuem um procedimento de soldagem aprovado. A junta selecionada para a elaboração do trabalho foi do tipo sobreposta com material de base de espessuras diferentes, respectivamente iguais a 1,00 e 0,78 mm. As juntas soldadas foram avaliadas por: ensaio de cisalhamento, dureza Vickers e caracterização microestrutural das diversas regiões das juntas soldadas. Foram realizadas análises por microscopia óptica e microscopia eletrônica de varredura usando espectrometria de energia dispersiva (MEV/EDS). Foi realizado o teste de hipótese como técnica para a análise dos dados provenientes dos ensaios experimentais. Nas juntas soldadas com ambos processos não foi verificada a presença de descontinuidades, poros e depressões na superfície do cordão. Os resultados indicam que as condições usadas em ambos os processos de soldagem foram satisfatórias e possibilitaram a soldagem do aço maraging 350 atendendo aos requisitos necessários. / In this work, the welds made by a continuous wave diode pumped solid state laser guided by fiber were studied and the results were compared with welded joints of electron beam welding. The material used was maraging 350 steel ASTM A 538 Grade C. The welding process performed with electron beam welding has a approved welding procedure. The joint chosen for the preparation of the work was the lap joint type with different thicknesses base material respectively equal to 1,00 and 0,78 mm. The welded joints were evaluated by mechanical tests like shear test, Vickers hardness and microstructural characterization of the various regions of the welded joints. Analyzes were performed by optical microscopy and scanning electron microscopy using energy dispersive spectrometry (SEM/EDS). The hypothesis test technique was done for the analysis of data from experimental tests. For both welding process was not detected in the welded joints the presence of discontinuities, pores and depressions on the weld fillet surface. The results indicate that the conditions used for both welding process were satisfactory and allowed the welding of maraging 350 steel meeting necessary requirements.

O objetivo deste trabalho foi comparar a eficácia da Tomografia Computadorizada Cone Beam e a Radiografia Periapical como métodos de proservação de lesões periapicais após o tratamento endodôntico. Foram avaliadas no estudo Radiografias e Tomografias de 1.462 indivíduos com fissura labiopalatina no Hospital de Reabilitação de Anomalias Craniofaciais Universidade de São Paulo, que compareceram para o tratamento endodôntico entre os anos 2009 e 2011. De acordo com os critérios de inclusão, foram selecionados 46 dentes unirradiculares com lesão periapical, os quais foram divididos nos grupos: avaliação Radiográfica (Grupo I) e avaliação Tomográfica (Grupo II). Os dados foram analisados por meio do escore PAI para as alterações periapicais encontradas. Nos resultados observou-se que houve diferença estatisticamente significativa nos grupos estudados. Em 34 casos os escores atribuídos às Tomografias dos dentes avaliados foram maiores do que os escores atribuídos às Radiografias Periapicais dos mesmos dentes avaliados, comprovando a maior precisão da Tomografia Computadorizada Cone Beam. Desta forma, a análise dos resultados obtidos neste trabalho permite constatar que a Tomografia Computadorizada Cone Beam é mais eficaz na proservação de lesões periapicais do que a Radiografia Periapical após o tratamento endodôntico em pacientes com fissura labiopalatina. / The aim of this study was to compare the effectiveness of Cone Beam Computed Tomography and periapical radiography as a follow-up method of periapical lesions after endodontic treatment. We evaluated in the study radiographs and tomography scans of 1,462 individuals with cleft lip and palate at the Hospital of Rehabilitation of Craniofacial Anomalies - University of Sao Paulo who came for treatment endodontic between the years 2009 and 2011. According to inclusion criteria were selected 46 single-rooted teeth with periapical lesions, which were divided into groups radiographic evaluation (Group I) and tomographic evaluation (Group II). Data were analyzed using the PAI score for periapical changes found. The results were observed that statistically significant differences in the groups studied. In 34 cases the CT scores attributed to the teeth evaluated were higher than the scores attributed to the radiographs of same teeth evaluated, demonstrating the greater precision of Cone Beam Computed Tomography. Thus, analysis of results obtained in this work demonstrates that the Cone Beam Computed Tomography is more effective in follow-up of periapical lesions than periapical radiography after endodontic treatment in patients with cleft lip and palate.

Dentre as atividades parafuncionais do sistema estomatognático, pode-se salientar o bruxismo, o qual pode se manifestar tanto durante o sono (BS), quanto durante o dia (Bruxismo Diurno BD) ocorrendo em distintos estados de consciência (sono e vigília). A Classificação Internacional dos Distúrbios do Sono define o bruxismo como &ldquo;um distúrbio com movimentos de padrão desordenado do sistema mastigatório que envolve o ranger ou apertar dos dentes durante o sono&rdquo;. O diagnóstico de bruxismo é realizado clinicamente, com base no relato de uma história prévia recente de sons de ranger de dentes que ocorreram pelo menos de 3 a 5 noites por semana, durante 6 meses. A presença de facetas de desgaste dental, manifestações de dor matinal nos músculos mastigatórios, a hipertrofia do músculo masseter, a hipersensibilidade ou estalo da Articulação Temporomandibular (ATM), impressões dentais na bochecha ou língua e mobilidade dental, entre outros, são sinais característicos desta parafunção. Não obstante, frente à crescente valorização do aspecto funcional, a avaliação não deve se restringir apenas ao exame clínico. Nesse sentido, a imaginologia vem se tornando um recurso de valor inestimável para a determinação de um diagnóstico. Assim, o objetivo do presente trabalho é descrever as possíveis alterações dos componentes anatômicos da articulação temporomandibular (ATM), de crianças com bruxismo, por meio da análise de imagens obtidas pela técnica de Tomografia Computadorizada Cone Beam. Com base nos critérios de inclusão e exclusão, foram selecionados 20 indivíduos, entre 7 e 11 anos de idade, do sexo masculino e feminino, em atendimento na Clínica Infantil da FORP USP. Na avaliação clínica para diagnóstico de bruxismo, foi evidenciado a presença de todas, ou algumas das seguintes alterações: presença de facetas de desgaste dental, fraturas de restaurações, fraturas dentais, impressões dentais em bochechas e língua, dor na ATM, ruído na ATM, dor nos músculos masseter e temporal. O exame tomográfico foi realizado em um aparelho de tomografia i-CAT e durante as reconstruções multiplanares, antes de gerar as imagens, o volume total do paciente foi transferido para o scanner com a utilização do plano de Frankfurt paralelo ao solo. Na análise de variáveis categóricas, utilizou-se teste Exato de Fisher e teste de Fisher com a extensão de Freeman-Halton. Foi considerado estatisticamente significante valor de p &le; 0,05. Em algum grau, todos os pacientes relataram dor à palpação dos músculos temporal e masseter, assim como à palpação da ATM. A presença de alterações na ATM somente apresentou significância estatística na presença de osteófitos na região articular do lado direito em associação com dor na articulação temporomandibular ipsilateral (p=0,04). Erosões e esclerose não foram encontradas em nenhum paciente e aplainamento foi um achado na totalidade dos indivíduos, porém, não apresentando relação estatísticamente significante quando cruzado com achados clínicos. A presença de dor no músculo temporal e a relação horizontal côndilo-fossa contralateral, apresentaram significância estatística (p<0,05). No músculo masseter essa associação apresentou significância estatística com a relação horizontal côndilo-fossa ipsilateral (p=0,01). Os achados sugerem que o bruxismo pode promover alterações significativas nas estruturas do sistema estomatognático desde a infância. / Among the parafunctional activities of masticatory system, bruxism can be higlighted. It occurs during sleep (Sleep Bruxism - SB) or wakefulness (Awake Bruxism - DB), which occur in two different states of consciousness (sleep and wakefulness). The International Classification of Sleep Disorders defines bruxism as \"a movement disorder with a stereotyped pattern of the masticatory system that involves teeth grinding or clenching during sleep.\" Bruxism is clinically diagnosed based on reports of teeth grinding noises that occurred at least three to five nights per week for 6 months. Also, the presence of wear facets, matutinal pain in the masticatory muscles, masseter muscle hypertrophy, temporomandibular joint (TMJ) noise or hypersensitivity, dental impressions on the cheek or tongue and tooth mobility, among others, are hallmarks of this parafunction. However, the evaluation should not be restricted to clinical examination since functional aspects are gaining importance. As consequence, imaging has become an invaluable resource for diagnosis. The objective of this paper is to describe possible changes in temporomandibular joint (TMJ) anatomical components in children with bruxism by Cone Beam Computed Tomography image analysis. Based on the inclusion and exclusion criteria, Twenty 7-11-years old male and female children treated at Ribeirão Preto Pediatric Dentistry Clinic, University of São Paulo, Brazil, were selected. The presence of all or some of the following changes was used in clinical evaluation for bruxism diagnosis in the present study: presence of wear facets, fractures in fillings, dental fractures, dental impressions in cheek and tongue, TMJ pain and clicking, masseter and temporalis muscles pain. The CT scan was performed on a i-CAT CT device and during multiplanar reconstructions, before obtaining image, the total volume of the patient was transferred to the scanner using the Frankfurt plane parallel to the ground. In Statistical analysis Fisher\'s exact test and Fisher\'s test with the Freeman-Halton extension were used for categorical variables. Values of p &le; 0.05 were considered statistically significant. In the results, all patients reported pain on palpation of the temporalis and masseter muscles, as well as TMJ palpation. Erosions and sclerosis were not found. Flattening was present in all individuals, however, no statistical significance was found between this feature and clinical findings. The presence of osteophytes in the TMJ was associated with ipsilateral pain in temporomandibular joint palpation (p = 0.04). There was an association between pain in the contralateral temporal muscle and the condyle-fossa relationship in the horizontal direction (p <0.05). There was also a correlation between pain in the ipsilateral masseter muscle and the condyle-fossa relationship in the horizontal direction (p = 0.01). In conclusion, our findings suggest that bruxism can promote significant changes in the structures of the stomatognathic system since childhood.

En utilisant des solutions de production issues des technologies de Fabrication Additive (FA), l’industrie s’ouvre de nouvelles possibilités pour la fabrication de pièces à haute valeur ajoutée. Dans le but d’être pleinement exploitables, ces procédés de fabrication doivent permettre la réalisation de pièces dont la qualité est adaptée aux besoins de l’industrie. Ces travaux se concentrent sur deux points ciblés de la maîtrise de la qualité en FA appliquée à la technologie Electron Beam Melting (EBM).Le premier point abordé s’intéresse à l’impact de la position d’une pièce dans l’espace de fabrication d’une machine sur la qualité géométrique de cette pièce. Pour caractériser l’espace de fabrication de la machine Arcam A1, plusieurs séries de pièces sont fabriquées à différentes localisation de l’espace, puis comparées à leur design initial. Les écarts mesurés entre les pièces et leur géométrie souhaitée montrent que la périphérie de l’espace de fabrication est une zone sujette à d’importants défauts géométriques. Ces défauts sont caractérisés et des solutions sont proposées pour en limiter l’impact sur la qualité géométrie des pièces.Le second point traite de la porosité des pièces fabriquées. Lorsque l’apport énergétique du faisceau d’électron n’est pas adéquat pour fondre correctement la poudre, des pores peuvent se former dans le matériau des pièces fabriquées. La géométrie et le matériau des pièces rendent difficiles la détection de ses pores. Une méthode de détection est proposée pour détecter la présence de pores dans une pièce via un contrôle standardisé sur un élément qui copie les conditions de fusion de la pièce. Cette méthode propose deux alternatives de contrôle : un contrôle optique (rapide, abordable mais peu précis) et un contrôle tomographique (plus précis que le précédent mais moins rapide et abordable). Un algorithme de traitement d’image innovant a été développé dans le cadre de cette étude afin de rendre les tomographies du témoin plus fiables. / By using production solutions from Additive Manufacturing (AM) technologies, the industry is opening up new possibilities for manufacturing high added value parts. In order to be fully exploitable, these manufacturing processes must allow the production of parts whose quality is adapted to the needs of the industry. This work focuses on two aiming points of quality control in AM applied to Electron Beam Melting (EBM) technology.The first point deals with the impact of a part position in the manufacturing space of a machine on the geometric quality of this part. To characterize the manufacturing space of the Arcam A1 machine, several series of parts are manufactured at different locations of the space, then compared to their initial design. The differences measured between the parts and their desired geometry show that the periphery of the manufacturing space is a zone subject to important geometrical defects. These defects are characterized and solutions are proposed to limit the impact on the geometrical quality of parts.The second point deals with the porosity of manufactured parts. When the energy supply of the electron beam is not adequate to melt the powder properly, pores can form in the material of the manufactured parts. The geometry and material of the parts make it difficult to detect its pores. A detection method is provided to detect the presence of pores in parts via a standardized control on an item that copies the parts merging conditions. This method offers two control alternatives: an optical control (fast, affordable but not very accurate) and a tomographic control (more accurate than the previous one but slower and costlier). An innovative image processing algorithm is developed as part of this study to make the item tomography scans more reliable.