Thesis (Ph.D.) - University of Glasgow, 2008. / Ph.D. thesis submitted to the Faculty of Information and Mathematical Sciences, Department of Statistics, University of Glasgow, 2008. Includes bibliographical references. Print version also available.

Thesis (Ph. D.)--University of Chicago, Dept. of Radiology, August 2000. / Includes bibliographical references. Also available on the Internet.

Thesis (M.Sc.)--York University, 2004. Graduate Programme in Earth and Space Science & Engineering. / Typescript. Includes bibliographical references (leaves 117-123). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url%5Fver=Z39.88-2004&res%5Fdat=xri:pqdiss &rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:MR11920

Orientador: Ruis Camargo Tokimatsu / Resumo: A modelagem tridimensional muito já contribuiu com a indústria do entretenimento e agora tem sido amplamente utilizada na manufatura e criação de novos produtos. A possibilidade de se ter um modelo de um produto a um preço menor e com uma maior rapidez tem feito essa técnica ser cada vez mais aceita em todas as áreas da engenharia. Quando já se tem um modelo real e deseja-se realizar alguma modificação, simulação ou mesmo replicar o produto, a engenharia reversa muito pode contribuir, pois permite a obtenção do modelo tridimensional a partir do objeto real. Os equipamentos de digitalização tridimensional têm um alto custo de investimento, mesmo os de baixa precisão. A comunidade de entusiastas de software e hardware livre busca também distribuir e popularizar o conhecimento compartilhando suas descobertas e contribuindo abertamente com outras iniciativas. Buscamos nesse projeto construir um scanner 3D utilizando software e hardware livre utilizando componentes de baixo custo e fácil aquisição, estabelecendo seus limites técnicos, estimulando assim a adoção de técnicas de engenharia reversa. O processo de calibragem, captura e pós tratamento da nuvem de pontos obtidas foi detalhado na construção de modelos para comparação de dimensões e levantamento de características da superfície do material. / Mestre

Submitted by Sandro Moreira (moreira.sandro@gmail.com) on 2017-01-18T18:23:17Z No. of bitstreams: 1 SandroMoreira-DissertacaoMestradoFinal.pdf: 12934831 bytes, checksum: a63cb94b201b877dc272a7bccad284bc (MD5) / Approved for entry into archive by LUIZA DE MENEZES ROMANETTO (luizamenezes@reitoria.unesp.br) on 2017-01-23T19:48:34Z (GMT) No. of bitstreams: 1 moreira_ss_me_ilha.pdf: 12934831 bytes, checksum: a63cb94b201b877dc272a7bccad284bc (MD5) / Made available in DSpace on 2017-01-23T19:48:34Z (GMT). No. of bitstreams: 1 moreira_ss_me_ilha.pdf: 12934831 bytes, checksum: a63cb94b201b877dc272a7bccad284bc (MD5) Previous issue date: 2016-12-06 / A modelagem tridimensional muito já contribuiu com a indústria do entretenimento e agora tem sido amplamente utilizada na manufatura e criação de novos produtos. A possibilidade de se ter um modelo de um produto a um preço menor e com uma maior rapidez tem feito essa técnica ser cada vez mais aceita em todas as áreas da engenharia. Quando já se tem um modelo real e deseja-se realizar alguma modificação, simulação ou mesmo replicar o produto, a engenharia reversa muito pode contribuir, pois permite a obtenção do modelo tridimensional a partir do objeto real. Os equipamentos de digitalização tridimensional têm um alto custo de investimento, mesmo os de baixa precisão. A comunidade de entusiastas de software e hardware livre busca também distribuir e popularizar o conhecimento compartilhando suas descobertas e contribuindo abertamente com outras iniciativas. Buscamos nesse projeto construir um scanner 3D utilizando software e hardware livre utilizando componentes de baixo custo e fácil aquisição, estabelecendo seus limites técnicos, estimulando assim a adoção de técnicas de engenharia reversa. O processo de calibragem, captura e pós tratamento da nuvem de pontos obtidas foi detalhado na construção de modelos para comparação de dimensões e levantamento de características da superfície do material. / The three-dimensional modeling has contributed much to the entertainment industry and has now been widely used in manufacturing and creating new products. The possibility of having a model of a product at a lower price and a higher speed have made this technique is increasingly accepted in all fields of engineering. When there is already a real model and you want to make any changes, simulation or even replicate the product, reverse engineering can greatly contribute, as it allows to obtain three-dimensional model from the real object. The three-dimensional scanning equipment have a high investment cost, even low accuracy. The community of enthusiasts of open source and open hardware also distribute and popularize knowledge sharing his findings and openly contribute to other initiatives. We seek in this study, build a scanner 3D using free software and hardware components using low-cost and easy acquisition, establishing its technical limits, stimulating the adoption of reverse engineering techniques. The calibration, capture and post-treatment process of the cloud of points obtained was detailed in the construction of models for comparison of dimensions and survey of surface characteristics of the material.

Household appliances utilize single-phase motors to perform everyday jobs whether it is to run a fan in an air conditioner or the compressor in a refrigerator. With the movement of the world going “green” and trying to make everything more efficient, it is a logical step to start with the items that we use every day. This can be done by replacing single-phase motors with three-phase motors in household appliances. Three-phase motors are 14% more efficient than single-phase motors when running at full load and typically cost less over a large range of sizes [1]. One major downside of incorporating three-phase motors in household appliance is that three-phase power is not readily available in homes. With the motor replacement, a single to three-phase converter is necessary to convert the single-phase wall power into the required three-phase input of the motor. One option is active conversion, which uses switches and introduces different stages that produce power loss [2]. An alternative solution is passive conversion that utilizes the resistances within the motor windings along with additional capacitors and inductors, which in theory are lossless. This study focuses on three different single to three-phase passive converters to run both wye and delta-connected three-phase induction motors, and a possible third winding configuration that utilizes one of the three converters. There will be an emphasis on proving the equivalency of two converters, one proposed by Stuart Marinus and Michel Malengret [11] and the other by Otto Smith [12]. Sensitivity analysis is performed to study the effects of variation of torque and converter component tolerances on the system.

In this thesis, we investigate the stochastic three dimensional Navier-Stokes-∝ model and the stochastic three dimensional Leray-∝ model which arise in the modelling of turbulent flows of fluids. We prove the existence of probabilistic weak solutions for the stochastic three dimensional Navier-Stokes-∝ model. Our model contains nonlinear forcing terms which do not satisfy the Lipschitz conditions. We also discuss the uniqueness. The proof of the existence combines the Galerkin approximation and the compactness method. We also study the asymptotic behavior of weak solutions to the stochastic three dimensional Navier-Stokes-∝ model as ∝ approaches zero in the case of periodic box. Our result provides a new construction of the weak solutions for the stochastic three dimensional Navier-Stokes equations as approximations by sequences of solutions of the stochastic three dimensional Navier-Stokes-∝ model. Finally, we prove the existence and uniqueness of strong solution to the stochastic three dimensional Leray-∝ equations under appropriate conditions on the data. This is achieved by means of the Galerkin approximation combines with the weak convergence methods. We also study the asymptotic behavior of the strong solution as alpha goes to zero. We show that a sequence of strong solution converges in appropriate topologies to weak solutions of the stochastic three dimensional Navier-Stokes equations. All the results in this thesis are new and extend works done by several leading experts in both deterministic and stochastic models of fluid dynamics. / Thesis (PhD)--University of Pretoria, 2010. / Mathematics and Applied Mathematics / unrestricted

Strategic use of energy storage systems alleviates imbalance between energy generation and consumption. Battery storage of various chemistries is favorable for its relatively high energy density and high charge and discharge rates. Battery voltage is in dc, while the distribution of electricity is still predominantly in ac. To effectively harness the battery energy, a dc-ac inverter is required. A conventional inverter contains two high-frequency switching stages. The battery-interfacing stage provides galvanic isolation and switches at high frequency to minimize the isolation transformer size. The grid-interfacing stage also operates at high frequency to obtain sinusoidal grid currents and the desired power. Negative consequences of high-frequency switching include increased switching loss and the generation of large voltage harmonics that require filtering. This dissertation proposes an alternative two-stage inverter topology aimed at reducing converter size and weight. This is achieved by reducing the number of high-frequency switching stages and associated filter requirements. The grid-interfacing stage is operated at the line frequency, while only the battery-interfacing stage operates at high frequency to shape the line currents and control power flow. The line-frequency operation generates negligible switching loss and minimal current harmonics in the grid-interfacing stage. As a result, the required filter is reduced in size. Hardware designs are performed and compared between the conventional and proposed converters to quantify expected size reduction. Control methods are developed and verified in simulation and experiment to obtain high-quality line currents at all power factors.

<p> Until now, the nuclear many body problem has been restricted almost entirely to considerations of the two-body force. However the meson theory of nuclear forces predicts that the exchange of mesons between three or more particles will give rise to a three-body or may-body force. The meson theory which has succesfully explained the main features of the phenomenological nucleon-nucleon potential, is expected to provide a good basis for the study of three-body nuclear forces. Three-body nuclcear forces can occur among baryons such as N, ∧, Σ, and Ξ. So far, however only bound states of nucleons(nuclei) and of nucleons and ∧ (hypernuclei) have been observed experimentally. Hence only the three-nucleon force and the ∧NN force are considered. It will be seen that the ∧NN force plays a more important role than the three-nucleon force. Thus in the present work the ANN force will be studied in greater detail than the three-nucleon force. First the long and intermediate range parts of the ∧NN force are derived from meson theory. Their effects on the binding energies of ^H,^5He and nuclear matter are then estimated. Since the short range part of the force is not known, no definite conclusion can be drawn. However it is found that the three-body ∧NN force can play and important role in the nuclear structure problem. The effects of the three-nucleon force in ^3H and in nuclear matter are also briefly discussed. </p> / Thesis / Doctor of Philosophy (PhD)

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