Thesis (Master of Engineering in Ocean Engineering)--University of California at Berkeley, 2004. / "January 2005." Description based on title screen as viewed on May 25, 2010. DTIC Descriptor(s): Fluid Dynamics, Lagrangian Functions, Equations Of Motion, Acceleration, Formulations, Grids, Continuum Mechanics, Gaussian Quadrature, Derivatives (Mathematics), Compact Disks, Boundary Value Problems, Polynomials, Interpolation, Pressure, Operators (Mathematics). DTIC Identifier(s): Multimedia (CD-Rom), Moving Grids, Meshless Discretization, Lifs (Lagrange Implicit Fraction Step), Lagrangian Dynamics, Meshless Operators, Mlip (Multidimensional Lagrange Interpolating Polynomials), Flux Boundary Conditions, Radial Basis Functions Includes bibliographical references (58-59).

Thesis (M.Eng.)--Memorial University of Newfoundland, 2003. / Bibliography: leaves 119-127.

Made available in DSpace on 2014-06-11T19:28:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-03-21Bitstream added on 2014-06-13T20:37:41Z : No. of bitstreams: 1 rodrigues_ea_me_bauru.pdf: 1602991 bytes, checksum: 7f755b87b5be84900b2d054f02413197 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / No presente trabalho desenvolve-se um modelo constitutivo baseado na mecânica do dano contínuo para representar o comportamento de materiais que apresentam diferentes respostas quando solicitados à tração ou à compreensão. obtem-se uma representação constitutiva através da composição de modelos simples e específicos para tratar cada tipo de solicitação. Este modelo combinado é capaz inclusive de lidar com carregamentos alternados (tração e compreensão), envolvendo fechamento e reabertura de fissuras existentes. Para modelar o comportamento em compreensão emprega-se o modelo constitutivo que tem como critério de degradação o segundo invariante do tensor de tensão desviador (critério de Von Mises ou J2). Para simular o aparecimento de fissuras de tração, usa-se o modelo de dano com critério de degradação baseado na energia de deformação da parte positiva do tensor efetivas. A integração dos modelos é feita com base em tensões efetivas associadas a duas escalas distintas (escala grosseira e refinada). O modelo é apto para representar a formação de descontinuidades no campo de deslocamento (descontinuidades fortes) em materiais quase-frágeis. Nesse caso, a região de localização de deformação (zona de processo da fatura) pode ser descrita pelo modelo de dano combinado, com lei de abrandamento de tensões (softening) exponencial, que estabelece dissipação compatível com a energia de fratura. A região contínua pode ser descrita pelo modelo de dano J2, com parâmetros ajustados com base no comportamento não linear à compreensão. Valida-se o modelo proposto mediante testes básicos, focando a capacidade do modelo em representar os principais aspectos do comportamento de materiais quase-frágeis. A aplicabilidade do modelo é demonstrada através do estudo da capacidade de rotação plástica de vigas de concreto armado, confrontando-se os resultados numéricos com os experimentais / A combined constitutive model based on the Continuum Damage Mechanics (CDM) is presented to represent the nonlinear behavior of quasi-brittle materials, which present different response when subjected to tension or compreession. The constitutive model is a composition of two simple and specific models designed to treat each type of behavior. The combined model is able to deal with alternating load (tension-compression), involving formation, closure and reopening cracks. To model the compressive behavior, a degradation criterion based on the second invariant of the deviatoric part of the effective stress tensor (Von Miser or J2 criterion) is used. To simulate cracking, a damage model with degradation criterion based on the strain energy associated to the positive part the effective stress tensor is adopted. The combination of the models is made on the basis of the effective stresses associated to two distinct scales (coarse and fine scales) The model is able to represented the formation of discontinuities in the displacement field (strong discontinuities) for quasi-brittle materials. The region of strain localization (fracture process zone) is described by a softening law which establishes dissipation energy compatible with the fracture energy. The continuous region is described by the J2 damage model, with parameters ajusted to describle the compressive nonlinear behavior in compression. Some basic tests are performed to asses the ability of the model to represent the main aspects of the behavior of quasi-brittle materials. The applicability of the model is demonstrated by the study of the plastic rotation capacity of reinforced concrete beams, comparing the numerical responses with the experimental ones

Made available in DSpace on 2014-06-11T19:28:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-08-29Bitstream added on 2014-06-13T19:58:09Z : No. of bitstreams: 1 lopesjunior_ja_me_bauru.pdf: 1162814 bytes, checksum: 6b95b841db7e1b2b5ce4cd33f600a04b (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Atualmente, na odontologia, após a perda de dentes por razões diversas, estes vêm sendo substituídos por implantes dentários. A importância e modelos computacionais biomecânicos é cada vez mais frequente, posto que essas ferramentas permitem simular o comportamento desses dispositivos que tentam restaurar as funções dos dentes perdidos. Como os aspectos biomecânicos de implantes são diferentes daqueles de um dente natural, circundando por um ligamento periodontal, a transferência da carga ao implante, e deste ao osso circundante, poide gerar esforços que, além de provocar falhas nas reabilitações, podem até ultrapassar o limite fisiológico e causar perda da osseointegração. Na análise desses sistemas de prótese, é essencial representar adequadamente as influências entre os diferentes componentes implante/coroa, que são comumente unidos através de parafusos. Falhas destas uniões podem prejudicar o correto funcionamento da prótese, ou até mesmo, produzir esforços não previstos, responsáveis por danos severos na prótese ou no osso. Assim, faz-se necessário descrever adequadamente o comportamento das interfaces entre os componentes dos sistemas protéticos. No presente trabalho, são utilizados elementos finitos sólidos tetraédricos com elevada razão de aspecto para representar a superfície de interface entre os componentes em contato implante/parafuso/coroa. Um modelo constitutivo de dano é empregado para reproduzir o comportamento desses elementos de interface. O modelo é desenvolvido para representar o comportamento diferenciado em tração e compressão na superfície de contato, permitir a separação dos componentes sem oferecer, praticamente, resistência, contudo, ao mesmo tempo, impedir movimentos de interpenetração no caso de solicitações compressivas no... / Currently, in dentistry, after loss of teeth for various reasons, they have been replaced by dental implants. The importance of biomechanical computer models is increasingly, since they tools allows for the simulation of the behavior of thes devices that try to restore the cunctions of missing teeth. As the biomechanical aspects of implants are different from those of natural tooth, surrounded by a periodontal ligament, the load transferred to the implant and the surrounding bone can generate stresses that, in addition to cause failures in rehabilitations, can even exceed the physiological limit and cause loss of osseointegration. In the analysis of these phosthetic systems, it is essential to adequately represent the interaction between different components that are commonly joined together by using screws. Possible joint failures can adversely affect the correct functioning of unions, or even produce stresses responsible for severe damage in prosthesis or bone. Thus, it is necessary to adequately describe the behavior of interfaces between components prosthetic systems. In this work, tetrahedral solid finite elements with high aspect ratio are used to represent the contact interface between components (implant/screw/Crown). A constitute damage model is employed to reproduce the behavior of these interface elements. The model is designed to represent the differentiated behavior in tension and compression on the contact surface, allowing the separation of the components without offering resistance, however, preventing movement of interpenetration in the case of compression on the contact. So it is expected that this... (Complete abstract click electronic access below)

Orientador: Antonio Carlos Ferreira Seridonio / Resumo: Esta tese é dedicada ao estudo teórico das propriedades de transp orte eletrônico do grafeno hosp edando um par de átomos adsorvidos em diferentes geometrias. Na primeira delas, verificamos a densidade lo cal de estados (LDOS) do plano de grafeno hos p edando um par de átomos adsorvidos, distantes entre si, no centro de uma célula hexagonal da rede. Nesta primeira configuração, efeitos de correlação revelaram uma es trutura multiníveis na LDOS e padrõ es de batimentos na densidade de estados (DOS) induzida. Amb os efeitos são anisotrópicos e o correm na vizinhança dos p ontos de Dirac. Em um segundo arranjo, estudamos a formação de estados ligados ao contínuo (BICs) adsorvendo um par de átomos em lados op ostos do plano de grafeno e colineares com o centro de uma célula hexagonal. Mostramos que nesta configuração a LDOS é caracterizada p or uma dep endência cúbica na energia e que um mecanismo de interferência Fano destrutiva assistida p or uma correlação de Coulomb nas impurezas leva a formação de BICs. Na terceira geometria, analisamos os efeitos do acoplamento não-lo cal de um par de átomos adsorvidos colineares a um átomo de carb ono da rede na LDOS do grafeno. Em tal arranjo, canais de tunelamento eletrônico distintos dão origem a um fator de interferência Fano q0, que se torna um parâmetro de controle natural do sistema. Verificamos três regimes distintos para o sistema: (i) quando q0 < qc1 (ponto crítico) uma dependência mista do pseudogap, ∆ ∝ | ε| , | ε| 2, leva o si... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In this thesis we present a detailed theoretical study of the electronic transp ort prop erties of graphene systems hosting a pair of adatoms in distinct geometries. In the first one, where the adatoms are placed distant from each other at the center of the hexagonal cell, we verify multilevels struture in the lo cal density of states (LDOS) and b eat patterns in the induced density of states (DOS) profiles due to correlation effects. The b oth findings are anissotropic and o ccour near the Dirac p oint. In the second system, we study the formation of b ound states in the continuum (BICs) in a pair of adatoms on opp osite sides of the graphene sheet and colinear with the center of the hexagonal cell. In such a set, we show that the LDOS is caracterized by a cubic dep endence in energy and that the Fano destrutive interference assisted by Coulomb correlation in the adatoms gives rise to the BICs formation. In the third configuration, we analyze the effects of the nonlo cal coupling in a pair of adatoms collinear to a carb on atom of the graphene sheet. In such a geometry, distinct tunneling paths lead to a Fano factor of interferance q0, which becomes a natural control parameter of the system. In this sense, we verify three distinct regimes: (i) when q0 < qc1 (critical point) a mixed dependence of the pseudogap, ∆ ∝ | ε| , | ε| 2, gives rise to a phase presenting spin-degenerates BICs; (ii) near to q0 = qc1, we find a pseudogap ∆ ∝ | ε| 2 , where the system is drives to a quan... (Complete abstract click electronic access below) / Doutor

The healing process of ruptured tendons is problematic due to scar tissue formation and deteriorated material properties. In some cases, it may take nearly a year to complete. Mechanical loading has been shown to positively influence tendon healing; however, the mechanisms remain unclear. Computational mechanobiology methods employed extensively to model bone healing have achieved high fidelity, but not yet been explored to understand tendon regeneration. The general objective of this thesis is to develop computational approaches to enhance the knowledge of the role that mechanical factors play in fibre re-organisation in healing tendons, by proposing an appropriate constitutive formulation, followed by analysing the mechano-adaptation of the models created when regulated by different biophysical stimuli. Curve fitting of an established hyperelastic fibre-reinforced continuum model introduced by Gasser, Ogden and Holzapfel (GOH) against experimental tensile testing data of rat Achilles tendons at four timepoints during the tendon repair was used and achieved excellent fits (0.9903 &LT; R² &LT; 0.9986). A parametric sensitivity study using a three-level central composite design, which is a fractional factorial design method, showed that the collagen-fibre-related parameters in the GOH model had almost equal influence on the fitting. The mechano-adaptation of the healing tendons when regulated by axial and principal strain predicted fibre re-organisation comparable to experimental findings, in contrast to models regulated by deviatoric strain. Also, mechano-adaptive models regulated by deviatoric strain were more spatially and temporally sensitive to different boundary conditions - length and loading magnitudes - than those regulated by axial and principal strain. This thesis describes that a hyperelastic fibre-reinforced mechano-adaptive model regulated by axial or principal strain is generally capable of describing the mechanobiological behaviours of healing tendons, and that further experiments should focus on establishing the localised structural and material parameters of collagen fibres and their mechano-adaptive behaviours in the healing tissue.

[pt] O presente trabalho tem como objetivo a modelagem de escoamentos através de meios porosos, sob o ponto de vista da Teoria Contínua de misturas. O fluido e o sólido, que compõe o meio poroso, são tratados como constituintes contínuos de uma mistura binária, onde não ocorrem reações químicas. Em todas as situações aqui tratadas o fluido é suposto Newtoniano e incompressível, enquanto o meio poroso é rígido, homogêneo e isotrópico. O trabalho pode ser dividido em duas partes principais. Na primeira são modelados escoamentos através de regiões contendo meios porosos saturados e regiões onde só existe o fluido. São discutidas condições de compatibilidade sobre as interfaces, que separam as regiões, e é estabelecido um modelo para escoamentos, nos quais não exista fluxo de massa através das interfaces. A segunda parte trata de escoamentos em meios porosos insaturados, onde é preciso se considerar o efeito de forças capilares. Nesta parte é estabelecido um modelo e são simuladas situações unidimensionais. São estudados vários casos entre eles o enchimento de uma placa porosa, com e sem efeitos de atrito e de forças gravitacionais. A obtenção de resultados, nestes casos, exige a solução numérica de um sistema hiperbólico não-linear de equações diferenciais. / [en] This work aims to a modelling of flow through a porous media based upon the Continuum Theory of Mixtures. The fluid and the solid, which composes the porous media, are assumed as continuous constituent of a binary mixture where chemical reactions do not occur. In all situations here considered, the fluid is assuned Newtonian and incompressíble, while the porous media is rigid, homogeneus and isotropic. This work can be divided in two main parts. In the first one, flows are modelled through regions containing saturated porous media and regions where there is nothing but the fluid. Conditions of compatibility in the interfaces that divide the regions are discussed and a flow modelling is stablished where there are no crosaflow through the interfaces. The second part is concerned with flows in unsaturated porous media, where the effect of capillery pressure is considered. In this Part a model is stablished and unidimensíonal situations are simulated. Several cases are studied and the filling-up of a porous plate is among them, with and without frictíon effect and gravitational forces. The obtainment of results, in such cases, requires the numeric solution of a non-linear hyperbolíc system of differential equations.

[pt] O presente trabalho visa dois objetivos. 0 primeiro, didático, é de apresentar algumas versões da Termodinâmica dos Meios Contínuos, elucidando suas semelhanças e diferenças várias formas da segunda lei são apresentadas, questionando-se em alguns casos as suas supostas generalidades. O segundo objetivo, de pesquisa, desenvolve na versão de Serrin os conceitos de Estabilidade Termodinâmica e Exergia, aplicando-os no estudo dos ciclos de Carnot e de Rankine. Através do conceito de função de acumulação introduz-se uma nova maneira de se determinar a eficiência dos referidos ciclos. Ainda na versão de Serrin, aplica-se a teoria de processos de transição no estudo do efeito Joule-Thomson. Os fluidos de trabalho são um gás ideal, caracterizado pela convexidade do seu espaço de estados, e um fluido de Van der Halls, que não possui a mesma característica. Finalmente, no contexto da Termodinâmica de Processos Irreversíveis é feita uma comparação entre as soluções de problemas de condução de calor em meios rígidos e elásticos lineares isotrópicos. / [en] The present work has two purposes. The first one is didactic. It intend to present many versions of the Continuun Thermodynamics discussing their resemblances and diferences. Many forms of the second law are presented and in some cases their supposed generalities are questioned. The second purpose lies on the basic research. It is carried out applying the Serrin s version the concepts of Thermodynamic Stability and Availability in the studied of the Carnot s and Rankine s cycles. By meaning of the accumulation function concept a newform to determine the efficience of the above cycles is introduced. On the other hand in the Serrin s version the theory of transition processes can be applied in the study of the Joule-Thomson effect. The working fluids are an ideal gas which is characterized by the convexity of it s state space and the Van der Waals fluid which is not provided of such characteristic. Finally in the context of the Irreversible Thermodynamics is made a comparison between the solutions of heat conduction problems in rigid and linear isotropic elastic continuum.

The notion of a curve played important role in the history of mathematical thought. This dissertation is focused on the conception of a curve in analysis, point set theory and topology. The rectification of curves and the notion of arc length are considered in connection with the history of analysis from antiquity to the beginning of the 20th century. "Measurement of curves" is also discussed from the measure-theoretic viewpoint and various definitions of linear measure and fractional dimension are described. Historically, there are two main approaches to understanding curves. Jordan defined a curve as a continuous image of a closed interval. However, his definition appeared to be too wide, since it was met by objects such as the Peano curve. In the point set theory, a curve is considered to be a one-dimensional continuum. The development of the dimension theory and the continuum theory, starting with the pioneering work of Bolzano, was motivated by the search for rigorous topological definition of a curve, a surface etc. Among "pathological" curves, that were often introduced as counterexamples in the development of modern analysis, we can find early examples of fractals. The fractal theory motivated further study of mathematical properties of these curves in the late 20th century, such as self-similarity and...

Seventeenth-century division violin music is not considered part of the classical canon, but its background as a European art form may make it seem “too Western” for traditional ethnomusicological study. The purpose of this thesis is twofold: first, I outline the historical context, transmission, and performance practice of division violin playing in England during the sixteenth and seventeenth centuries. Also of interest to me is the way in which we, as musicologists, study oral tradition within the context of a musical culture that no longer exists today. After an exploration of the ideas of Milman Parry and Albert Lord, Walter Ong, Ruth Finnegan, and Slavica Ranković, I discuss the English division violin’s background and transition from a largely oral to a predominantly literate tradition. I demonstrate this change in transmission, composition, and performance practices through examining the second and sixth editions of John Playford’s The Division Violin (1684).