Inelastic behavior in steel special moment frames occurs through the development of plastic hinges at locations near the ends of the beam. The main objective of using a reduced beam connection is to force the formation of plastic hinges to be formed at the reduced beam section rather than at the ends of the beam which otherwise would lead to brittle failure of the beam-column connections. The beam has two reduced beam sections, each located at a certain distance from the face of the column, so that the plastic hinges are formed symmetrically at each of this section. When acted upon by lateral loads, the maximum moments occur at the ends of the beam. Therefore, the plastic hinges form at the reduced beam section. However, when a frame is subjected to a combination of gravity and lateral loads, the plastic hinge formation at one of the reduced beam section is not so clear and further analysis has to be done to study the effect. FEMA 350 indicates that the desired plastic hinge location is only valid for beams with gravity loads representing a small portion of the total flexural demand. If gravity demands significantly exceed 30% of the girder plastic capacity then further plastic analysis of the frame should be performed to determine the appropriate hinge locations. The scope of my thesis is mainly to study the combined effect of gravity and lateral loads on the formation of plastic hinges in steel moment frames with reduced beam section connections.

Optical microscopy is a cornerstone of biomedical research. Advances in optical techniques enable specific, high resolution, sterile, and biologically compatible imaging. In particular, beam shaping has been used to tailor microscopy techniques to enhance microscope performance. The aim of this Thesis is to investigate the use of novel beam shaping techniques in emerging optical microscopy methods, and to apply these methods in biomedicine. To overcome the challenges associated with high resolution imaging of large specimens, the use of Airy beams and related techniques are applied to light-sheet microscopy. This approach increases the field-of-view that can be imaged at high resolution by over an order of magnitude compared to standard Gaussian beam based light-sheet microscopy, has reduced phototoxicity, and can be implemented with a low-cost optical system. Advanced implementations show promise for imaging at depth within turbid tissue, in particular for neuroscience. Super-resolution microscopy techniques enhance the spatial resolution of optical methods. Structured illumination microscopy is investigated as an alternative for electron microscopy in disease diagnosis, capable of visualising pathologically relevant features of kidney disease. Separately, compact optical manipulation methods are developed with the aim of adding functionality to super-resolution techniques.

Programa de Pós-Graduação em Engenharia de Materiais. Departamento de Engenharia Metalúrgica, Escola de Minas, Universidade Federal de Ouro Preto. / Submitted by giuliana silveira (giulianagphoto@gmail.com) on 2016-04-13T17:47:11Z No. of bitstreams: 1 DISSERTAÇÃO_CaracterizaçãoFluxoMolde.pdf: 5643513 bytes, checksum: 3301dee56729473e8972000da5e9f9cd (MD5) / Approved for entry into archive by Oliveira Flávia (flavia@sisbin.ufop.br) on 2016-04-15T15:17:52Z (GMT) No. of bitstreams: 1 DISSERTAÇÃO_CaracterizaçãoFluxoMolde.pdf: 5643513 bytes, checksum: 3301dee56729473e8972000da5e9f9cd (MD5) / Made available in DSpace on 2016-04-15T15:17:52Z (GMT). No. of bitstreams: 1 DISSERTAÇÃO_CaracterizaçãoFluxoMolde.pdf: 5643513 bytes, checksum: 3301dee56729473e8972000da5e9f9cd (MD5) Previous issue date: 2016 / É uma estratégia comum, em processos de lingotamento contínuo de beam blank, a utilização de apenas uma válvula submersa, em função das dificuldades operacionais de se trabalhar utilizando duas. O desafio é desenvolver uma geometria de válvula que garanta uma solidificação mais homogênea no molde. Neste estudo foram determinadas as características do fluxo em molde de beam blank quando se usa somente uma válvula submersa. Os tipos de válvula analisados foram a tubular e uma composta por três portas laterais na saída, espaçados a 120°. Modelagem física e matemática foram empregadas para avaliar a distribuição de velocidades no plano de simetria e em planos paralelos a superfície do flange. A utilização de uma única válvula tubular resultou em aumento na profundidade de penetração do jato, porém em relação ao campo de velocidade na região do menisco não houve variação significativa em comparação com a utilização de duas válvulas tubulares. Os valores de flutuação superficial para este tipo de válvula foram inferiores ao da válvula com portas laterais e independentes da vazão de fluido. Para a válvula submersa com portas laterais os resultados evidenciaram a existência de maiores intensidades de flutuação do menisco e altas velocidades de impacto dos jatos de líquido no centro do flange oposto e nas quinas do flange adjacente à válvula. Para as condições investigadas, a intensidade de flutuação do menisco foi dependente da inclinação das portas de saída, da profundidade de imersão da SEN e da velocidade de lingotamento. Enquanto que, as velocidades de impacto no flange não foram fortemente afetadas pela variação destes ângulos das portas da válvula submersa. Os resultados obtidos via modelagem matemática estão em boa concordância com os de simulação física. __________________________________________________________________________________________ / ABSTRACT : It’s a common strategy in continuous casting process of beam blank the use of only one submerged entry nozzle due to operational difficulties related to the simultaneous use of two of them. The challenge is to develop a nozzle design that guarantees a more homogenous solidification in the mold. This work is related to the flow pattern in a beam blank mold when a single submerged entry nozzle is used. The SEN designs were a straight through tubular nozzle and a nozzle with three lateral ports distancing 120° from each other. Physical and mathematical modeling have been used to evaluate the velocity distribution and the meniscus behavior. One straight tubular nozzle leads to a deeper jet penetration, but the velocity distribution at the meniscus region is not remarkably different as compared to velocity distribution when two tubular nozzles are simultaneously employed. One straight tubular nozzle is characterized by surface oscillation which is almost independent of liquid flow rate. Surface oscillation and impact velocity at flange surface were significantly larger than those developed by the single straight tubular nozzle. The intensity of surface oscillation was found to be dependent on port angle, nozzle immersion depth and casting rate. The impact velocity at flange surface was not affected by the port angles. A good agreement between results from mathematical and physical modeling has been found.

The elasto-dynamics of flexible frame structures is of interest in many areas of engineering. In certain structural systems the deflections can be large enough to warrant a nonlinear analysis. For example, offshore structures, long suspension bridges and other relatively slender structures used in space applications require a geometrically nonlinear analysis. In addition, if the structure has deployable elements, as in some space structures, the required analysis becomes even more complex. Typical examples are spacecraft antennae, radio telescopes, solar panels and space-based manipulators with deployable elements. The main objective of the present work is to formulate the problem of sliding beams undergoing large rotations and small strains. Further we aim to develop efficient finite element technique for analysis of such complex systems. Finally we wish to examine the nature of the motion of sliding beams and point out its salient features. We start with two well known approaches in the nonlinear finite element static analysis of highly flexible structures, namely, the updated Lagrangian and the consistent co-rotational methods and extend these techniques to dynamic analysis of geometrically nonlinear beam structures. We analyse several examples by the same methods and compare the performance of each for efficiency and accuracy. Next, using McIver's extension of Hamilton's principle, we formulate the problem of geometrically flexible sliding beams by two different approaches. In the first the beam slides through a fixed rigid channel with a prescribed sliding motion. In this formulation which we refer to as the sliding beam formulation, the material points on the beam slide relative to a fixed channel. In the second formulation the material points on the fixed beam are observed by a moving observer on a sliding channel and the beam is axially at rest. The governing equations of motion for the two formulations describe the same physical problem and by mapping both to a fixed domain, using proper transformations, we show that the two sets of governing equations become identical. It is not, possible to find analytical solutions to our problem and we choose the Galerkin numerical method to obtain the transient response of the problem for the special case axially rigid beam. Next we follow a more elegant approach wherein we use the developed incremental nonlinear finite element approaches (the updated Lagrangian and the consistent co-rotational method) in conjunction with a variable time domain beam finite elements (where the number of elements is fixed and as mass enters the domain of interest, but the sizes of elements change in a prescribed manner in the undeformed configuration). To verify the formulation and its computational implementation we analyse many examples and compare our findings with those reported in the literature when possible. We also use these illustrative examples to identify the importance of various terms such as axial flexibility and foreshortening effects. Finally we look into the problem of parametric resonance for the beam with periodically varying length and we show that the regions of stability obtained in the literature, using a linear analysis, do not hold when a more realistic nonlinear analysis is undertaken. / Graduate

Orientadores: Jacobus Willibrordus Swart, Stanislav Moshkalev / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-13T05:10:33Z (GMT). No. of bitstreams: 1 Silva_MarceloMacchida_M.pdf: 6148337 bytes, checksum: d4ca724ac84a5417bdd4995685227913 (MD5) Previous issue date: 2007 / Resumo: A nanotecnologia e uma área nova e promissora que englobam muitas disciplinas de ciência e engenharia. Seu rápido crescimento nas ultimas duas décadas é devido ao crescimento simultâneo na fabricação e caracterização de materiais em escala nanométrica. O objetivo deste trabalho é desenvolver uma técnica de processo híbrido para a fabricação de micro e nanocontatos assim como sua caracterização elétrica. Esse processo híbrido combina a fotolitografia seguida da técnica de lift-off e a deposição de platina por FIB. Para determinar a resistividade da platina depositada por FIB (Focuded Ion Beam), foram fabricas estruturas quadradas variando sua espessura de 5 nm - 100 nm e sua área 150 µm 150 µm e 20 µm x 20 µm. Resistores com comprimento de 30 µm variando sua área de secção (50 nm x 50 nm - 1 µm x 1 µm) foram fabricados a fim de uma melhor na caracterização do processo de deposição do filme de Pt assim como sua caracterização elétrica. As medidas elétricas foram realizadas na estação Keythley 4200 SCS, onde foi utilizado o método de quatro pontas nas estruturas quadradas para a caracterização da resistividade. Nos resistores utilizamos a configuração de dois terminais para a caracterização de resistência dos nanocontatos. / Abstract: Nanoscale science and technology is a young and burgeoning field that encompasses nearly every discipline of science and engineering, the rapid growth of the field in the past decades has been enable by the sustained advances in the fabrication and characterization of materials. This work presents the hybrid process for fabrication of micro and nanocontacts, this process include the lift - off technique and platinum deposited by FIB. For measurements, two types of test structures were fabricated: (i) 150 x 150 µm and 20 x 20 µm squares with thickness of 5, 10, 30 and 100 nm, and (ii) 30 µm long resistors with variable cross - section (50 nm x 50 nm to 1 µm x 1 µm). The Pt film resistivity has been measured by a four points probe method. / Mestrado / Eletrônica, Microeletrônica e Optoeletrônica / Mestre em Engenharia Elétrica

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Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第16847号 / 工博第3568号 / 新制||工||1539(附属図書館) / 29522 / 京都大学大学院工学研究科原子核工学専攻 / (主査)教授 伊藤 秋男, 准教授 柴田 裕実, 准教授 松尾 二郎 / 学位規則第4条第1項該当

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Beams of light carrying orbital angular momentum, such as vortex beams, have many applications in imaging and micromanipulation. We focus on applications in communication, in particular for quantum key distribution, where the security of communication channels is enhanced with the laws of quantum mechanics. However, this procedure requires superpositions of vortex beams. We want to generate such beams using integrated optics components due to their small size and their advantages in scalability and stability. Angular gratings, which are ring resonators with an embedded Bragg grating, are integrated structures known to generate vortex beams. We propose that a ring resonator with two embedded Bragg gratings, each on the inner and outer sidewalls, would generate a superposition of vortex beams. We verify this claim through analytical models, simulations and experiments.