Thesis (Ph. D.)--Florida State University, 2006. / Advisor: Paul Eugenio, Florida State University, College of Arts and Sciences, Dept. of Physics. Title and description from dissertation home page (viewed June 8, 2006). Document formatted into pages; contains xix, 155 pages. Includes bibliographical references.

Thesis (M.C.E.)--University of Delaware, 2007. / Principal faculty advisor: Jennifer Righman McConnell, Dept. of Civil & Environmental Engineering. Includes bibliographical references.

Thesis (MSc)--University of Stellenbosch, 2006. / Bibliography. Also available via the Internet.

Made available in DSpace on 2014-06-11T19:25:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-08-14Bitstream added on 2014-06-13T19:12:00Z : No. of bitstreams: 1 maia_eja_me_ilha.pdf: 1754554 bytes, checksum: 2445cdb8f92fe2f4eff2809012e1aff1 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Este trabalho foi realizado com o intuito de se conhecer, através de análise experimental, o comportamento de vigas de alvenaria estrutural de blocos de concreto quando estas forem submetidas à flexão simples. Durante o trabalho foi ensaiado o total de oito vigas com a utilização de blocos tipo canaleta (14x19x29) na primeira fiada e meia canaleta (14x19x14) na segunda fiada, sendo todas preenchidas por graute. Nos elementos fez-se o uso de armadura transversal e também foram executados quatro tipos de armaduras longitudinais, a saber: A1 (210), A2 (212,5), A3 (412,5) e A4 com armadura dupla (412,5 e 212,5). Em analogia com vigas de concreto armado, a viga A1 foi dimensionada para ruptura no domínio 2a, A2 no domínio 2b, A3 no domínio 3 e A4 de modo a observar como trabalha uma com armadura dupla. A obtenção de dados foi através de extensômetros elétricos que foram instalados na região central das armaduras longitudinais. Também foram instalados extensômetros elétricos nas faces superiores e nas laterais inferiores das vigas, de maneira que se conheçam as deformações atuantes no elemento. Foram utilizados LVDT instalados nas laterais das vigas para que se obtenham os valores das flechas nas vigas / This work was accomplished with the intention of knowing, through experimental analysis, the behavior of beams of structural masonry with concrete blocks when they are subjected to simple bending. During the work it was tested eight beams in total using the groove type block (14x19x29) in the first tier and half-groove (14x19x14) in the second tier, all of them filled with graute. In the elements it was used the transverse reinforcement and also were executed four types of longitudinal reinforcement, to know: A1 (210), A2 (212,5), A3 (412,5) and A4 with double reinforcement (412,5 e 212,5). Analogously with reinforced concrete beams, the A1 beam was dimensioned to rupture in the field 2a, A2 in the field 2b, A3 in the field 3 and the A4 to observe the way the double reinforced beam works. Obtaining data was using strain gages that were installed in the central region of the longitudinal reinforcement. Strain gages were also installed in the upper faces and the lower side of the beams, so we know the strain acting on the element. Were used LVDT installed on the sides of the beams order to obtain the values of the arrows in the beams

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

Made available in DSpace on 2014-06-11T19:23:01Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-03-01Bitstream added on 2014-06-13T19:08:45Z : No. of bitstreams: 1 inocente_gf_me_botib_parcial.pdf: 154662 bytes, checksum: 5921ceccb0c44aabd533516159600fa1 (MD5) Bitstreams deleted on 2015-03-16T11:30:18Z: inocente_gf_me_botib_parcial.pdf,Bitstream added on 2015-03-16T11:31:02Z : No. of bitstreams: 1 000709627.pdf: 615342 bytes, checksum: ecb29e15c1848924480b318430ee4378 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Um dos métodos mais utilizados para tratamento de câncer e o uso da radiação. Nesse contexto surge a terapia com feixes de prótons em frente a radioterapia convencional. Sabe-se que com a protonterapia há mais vantagens para o paciente tratado quando comparada com os métodos mais convencionais. A dose distribuída ao longo do caminho percorrido, principalmente nos tecidos sadios - região vizinha ao tumor, e menor e a acurácia do tratamento é muito melhor. Para a realização do tratamento, o paciente passa por alguns procedimentos e um deles é realizar uma imagem para visualização e localização do volume alvo. O principal método para obter essas imagens e a tomografia computadorizada de raios-X (XCT). Para o tratamento com feixes de prótons essa técnica de imagem pode gerar algumas incertezas. A proposta deste estudo é analisar a viabilidade de se reconstruir imagens geradas a partir da irradiação com feixes de prótons, e com isso diminuir algumas imprecisões, já que ser a o mesmo tipo de radiação para planejamento como tratamento, é também para diminuir drasticamente alguns erros de localização, uma vez que o planejamento poder a ser feito no mesmo local e em instantes antes onde o paciente ser a tratado. Este trabalho tem por finalidade, obter uma rela ção entre a propriedade intrínseca da interação de fótons e prótons com a matéria. Para isso utilizaremos de simulação computacional baseada no método de Monte Carlo, com os códigos SRIM 2008 e MCNPX v.2.5.0, para reconstruir imagens através da técnica utilizada na tomografia computadorizada convencional / The radiation method is one of the most used for cancer treatment. In this context arises therapy with proton beams in front of conventional radiotherapy. It is known that with protontherapy there are more advantages to the patient treatement when compared with more conventional methods. The dose distributed along the path, especially in healthy tissues neighbor the tumor, is smaller and the accuracy of treatment is much better. To carry out the treatment, the patient undergoes a plan through images for visualization and location of the target volume. The main method for obtaining these images is computed tomography X-ray (XCT). For treatment with proton beam this imaging technique can to generate some uncertainties. The purpose of this study is to analyse the feasibility of reconstructing images generated from the irradiation with proton beams, thereby reducing some inaccuracies, as it will be the same type of radiation as treatment planning, and also to drastically reduce some errors location, since the planning can be done at the same place and just before where the patient is treated. This study aims to obtain a relationship between the intrinsic property of the interaction of photons and protons with matter. For this we use computational simulation based on Monte Carlo method with the code SRIM 2008 and MCNPX v.2.5.0, to reconstruct images using the technique used in conventional computed tomography

Made available in DSpace on 2014-10-09T12:52:12Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:01:02Z (GMT). No. of bitstreams: 0 / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology, 2018. / In this research, we undertake a numerical study of the interaction between laser beams and two as well as multi-level atoms. The main aim of this research is to obtain a deeper understanding of laser-atom interactions and non-linear processes such as optical four-wave mixing. This work will supplement experiments to be conducted by other members of the group, who are involved in generating entangled photons via four-wave mixing in cold rubidium atoms. We begin by performing a basic study of the interaction between laser beams and two-level atoms as an aid to gain knowledge of numerical techniques, as well as an understanding of the physics behind light-atom interactions. We make use of a semi-classical approach to describe the system where the atoms are treated quantum mechanically and the laser beams are treated classically. We study the interaction between atoms and laser beams using the density matrix operator and Maxwell's equations respectively. By solving the optical Bloch equations for two-level atoms we examine the atomic populations and coherences and present plots of the density matrix elements as a function of time. The e ects of various parameters such as laser intensity, detuning and laser modulation have been tested. The behaviour of the laser beam as it propagates through the atomic sample is also studied. This is determined by Maxwell's equation where the atomic polarization is estimated from the coherence terms of the density matrix elements. / French South African Institute of Technology National Research Foundation

Orientador: Joel Mesa Hormaza / Banca: Roberto Morato Fernandez / Banca: João Dias de Toledo Arruda Neto / Resumo: Um dos métodos mais utilizados para tratamento de câncer e o uso da radiação. Nesse contexto surge a terapia com feixes de prótons em frente a radioterapia convencional. Sabe-se que com a protonterapia há mais vantagens para o paciente tratado quando comparada com os métodos mais convencionais. A dose distribuída ao longo do caminho percorrido, principalmente nos tecidos sadios - região vizinha ao tumor, e menor e a acurácia do tratamento é muito melhor. Para a realização do tratamento, o paciente passa por alguns procedimentos e um deles é realizar uma imagem para visualização e localização do volume alvo. O principal método para obter essas imagens e a tomografia computadorizada de raios-X (XCT). Para o tratamento com feixes de prótons essa técnica de imagem pode gerar algumas incertezas. A proposta deste estudo é analisar a viabilidade de se reconstruir imagens geradas a partir da irradiação com feixes de prótons, e com isso diminuir algumas imprecisões, já que ser a o mesmo tipo de radiação para planejamento como tratamento, é também para diminuir drasticamente alguns erros de localização, uma vez que o planejamento poder a ser feito no mesmo local e em instantes antes onde o paciente ser a tratado. Este trabalho tem por finalidade, obter uma rela ção entre a propriedade intrínseca da interação de fótons e prótons com a matéria. Para isso utilizaremos de simulação computacional baseada no método de Monte Carlo, com os códigos SRIM 2008 e MCNPX v.2.5.0, para reconstruir imagens através da técnica utilizada na tomografia computadorizada convencional / Abstract: The radiation method is one of the most used for cancer treatment. In this context arises therapy with proton beams in front of conventional radiotherapy. It is known that with protontherapy there are more advantages to the patient treatement when compared with more conventional methods. The dose distributed along the path, especially in healthy tissues ���� neighbor the tumor, is smaller and the accuracy of treatment is much better. To carry out the treatment, the patient undergoes a plan through images for visualization and location of the target volume. The main method for obtaining these images is computed tomography X-ray (XCT). For treatment with proton beam this imaging technique can to generate some uncertainties. The purpose of this study is to analyse the feasibility of reconstructing images generated from the irradiation with proton beams, thereby reducing some inaccuracies, as it will be the same type of radiation as treatment planning, and also to drastically reduce some errors location, since the planning can be done at the same place and just before where the patient is treated. This study aims to obtain a relationship between the intrinsic property of the interaction of photons and protons with matter. For this we use computational simulation based on Monte Carlo method with the code SRIM 2008 and MCNPX v.2.5.0, to reconstruct images using the technique used in conventional computed tomography / Mestre

Made available in DSpace on 2014-10-09T12:52:12Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:01:02Z (GMT). No. of bitstreams: 0 / O polietileno de ultra alto peso molecular (UHMWPE) é um plástico de engenharia que tem várias aplicações atualmente, mormente em áreas específicas da indústria e da medicina. O UHMWPE pode ser utilizado ainda em outras aplicações: defensas portuárias; guias de corrente; revestimentos de caçambas, silos e calhas; engrenagens; buchas; guias de correias e próteses cirúrgicas. Esta gama de aplicações se deve ao fato das excelentes características técnicas que este material possui, como: alta resistência a abrasão, elevada resistência ao impacto, anti-aderência, atóxico, excelente resistência química, baixo peso específico, fácil usinagem e alta resistência a fadiga. Os tipos de polietileno de ultra alto peso molecular (UHMWPE) utilizados neste trabalho foram o UTEC 3041 e UTEC 6541 da Braskem. A reciclabilidade do UHMWPE ganhou interesse, porque a utilização desta matéria-prima na última década cresceu mais de 600%, tornando-se um dos plásticos de engenharia mais utilizados para obtenção de peças usinadas depois da poliamida. Com o crescimento na utilização deste polímero na confecção de peças para maquinários, o seu desperdício tem sido muito grande, porque o resto deste material é desprezado, geralmente não sendo reaproveitado. Este trabalho tem como objetivo reciclar o UHMWPE UTEC 3041 e estudar as propriedades deste material virgem e reciclado e comparar os resultados entre si e com o UHMWPE UTEC 6541, e com estes materiais submetidos a diferentes doses de radiação. / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP