Bibliography: p. 82-83. / Issued also as a M.S. thesis in the Dept. of Electrical Engineering, 1968. / DSR Project no. 79723.

The global population is predicted to increase to around 11 billion by 2100. By 2050, the average age in the most populous age group will be over sixty. The ageing population (over sixty-five) is projected to exceed the number of children by 2047. These demographics imply that as the ageing population section increases, there will be a greater need for long-term care services. In order to adequately prepare against this trend, medical experts and evidence-driven policymakers are realising that personalised healthcare can help alleviate the burden related to the planning and commissioning of services allied to long-term care. Central to this picture is conditions that affect the brain - the most important organ of the human body. Dementia, stroke, and other conditions have a tremendous impact on loss of life, quality of life and healthcare cost. The challenge regarding brain disease is exacerbated further due to the difficulty regarding accessibility of this organ, but also due to the immense complexity regarding its morphology and functionality. In this context, advanced biophysical modelling is considered a promising option for studying brain pathophysiology and becomes a priority investment regarding routes for brain research. Simulations offer the promise of improved, clinically relevant, predictive information, acceleration for the pipeline of drug discovery/design and better planning of long-term care for patients. Within this paradigm, a particular model of water transport in the cerebral environment is essential. Numerous brain disorders arise from water imbalance in the cerebral environment, such as hydrocephalus (HCP), oedema and Chiari malformations to name a few. In this research, a novel multiscale model of fluid regulation and tissue displacement in the cerebral environment is developed, arising from the use of Multiple-network Poroelastic Theory (MPET). Characteristics of a four-network poroelastic model (4MPET) are first explored. Then, this model is extended to a fully dynamic (transient) six-network model (6MPET) via the addition of two new compartments, namely the glial cells compartment and the glymphatic system compartment. The introduction of these two compartments in the MPET paradigm reflects recent seminal findings in cerebral physiology, namely the extent and importance regarding transport/clearance of the perivascular spaces of the brain vasculature. We develop and present a numerical implementation of the 6MPET model, and we utilise this framework to analyse acute HCP and cerebral oedema in a variety of settings, in order to show the enhanced capability of the proposed 6MPET model compared to the classical 4MPET. Investigations of acute hydrocephalus through the fully dynamic 6MPET reveal compensatory trans-ependymal pressure behaviour in the glymphatic compartment. It was also shown that aquaporin-4 (AQP4) deficient expression exaggerates ventriculomegaly, and this too is demonstrated in acute hydrocephalus. Additionally, using the 6MPET model, one is able to witness three mitigating factors for cytotoxic oedema. Specifically, these are: reducing water mobility in the glial cells compartment, increasing the compliance of the glial cells compartment and finally AQP4-deficient expression.

Orientador: Katia Lucchesi Cavalca / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-17T18:55:49Z (GMT). No. of bitstreams: 1 Brol_KellenAparecida_M.pdf: 3493590 bytes, checksum: d557f6d9fa926676e3150289b0b3bc08 (MD5) Previous issue date: 2011 / Resumo: Uma máquina rotativa é composta por muitos componentes interconectados, que atuam em conjunto e a influência mútua ocasiona uma grande variedade de fenômenos durante seu funcionamento. Os modelos matemáticos visam simular o comportamento dinâmico destes sistemas, com o objetivo de representar uma condição real, e para ser útil na previsão da resposta do sistema. Esse tipo de informação pode ser aplicado na solução de problemas durante a fase de projeto, e, além disso, pode servir como entrada em modelos baseados nas técnicas de diagnósticos de falhas. Neste caso, um modelo computacional robusto permite um "design" otimizado, redução de custos e melhoria da confiabilidade. O objetivo deste trabalho é observar a influência da estrutura de suporte ou fundação no comportamento dinâmico de uma estrutura através dos métodos de impedância mecânica e coordenadas modais, sendo neste último caso, aplicando a redução modal e análise de sensibilidade qualitativa da mesma na influência da resposta dinâmica do sistema. A fundação é responsável pelo suporte do rotor, através da interconexão com os mancais. Os mancais transmitem à fundação, as forças causadas pelo movimento do rotor, como no desbalanceamento e vice-versa. Os modos de vibrar da fundação são excitados no intervalo de freqüência do rotor são também transmitidos através dos mancais de volta ao rotor. O método de coordenadas mistas usualmente considera o amortecimento estrutural proporcional e, portanto, ele representa o sistema em coordenadas modais desacopladas. Assim, foi verificada a igualdade entre os métodos de análise considerando todos os modos; para a combinação de modos reduzidos foi determinado o número mínimo de modos que representam a estrutura de suporte com amortecimento proporcional e não proporcional e a maneira como o amortecimento ficava acoplado ao sistema; e no caso do método das coordenadas mistas com uma fundação experimental de entrada, determinou-se o número mínimo de modos quando acoplados ou desacoplados ao sistema e tipo de amortecimento estrutural da fundação / Abstract: A rotating machine is composed by many interconnected components that work together and therefore they influence each other causing a wide range of phenomena during operation. The mathematical models allow to simulate the dynamic behavior of these systems in order to represent the reality, and, then, to be useful in predicting the system response. Such information can be applied to solve problems during the design phase, and, moreover, it can be the input to model based on failure diagnosis techniques. In this case, a robust computational model also enables the design optimization, cost reduction and reliability improvement. The objective of this work is to observe the support structure, or foundation, influence in the dynamic behavior of a structure through the methods of mechanical impedance and modal coordinates, and in the latter case, applying the reduced modal and sensitivity analysis of the same qualitative influence on the system dynamics response. The foundation is responsible for supporting the rotor, through interconnection with the bearings. The bearings transmit the foundation forces caused by the rotor movement, as those due to the mass imbalance, and vice versa. The vibration modes of the foundation are excited in the rotor frequency range also transmitted through the bearings back into the rotor. The coordinate method usually considers the mixed proportional structural damping, and therefore it represents the system in modal coordinates uncoupled. Thus was established the equality between the analysis methods for all modes; for the reduced modes combination was determined the minimum modes number that represent the support structure with proportional damping and non-proportional damping and the way that was connected to the system; and in the case the mixed coordinates method with a experimental foundation input, it was determined the minimum modes number when coupled and uncoupled system and the type of foundation structural damping / Mestrado / Mecanica dos Sólidos e Projeto Mecanico / Mestre em Engenharia Mecânica

Orientadores: Mario Jino, Adalberto Nobiato Crespo / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-25T04:04:06Z (GMT). No. of bitstreams: 1 Silva_OdairJacintoda_M.pdf: 2238493 bytes, checksum: 120710575da3bbe9052b22a2df5a3a07 (MD5) Previous issue date: 2014 / Resumo: Diversos estudos publicados indicam que a capacidade preditiva dos modelos de confiabilidade de software, que utilizam a informação da cobertura observada durante os testes, é melhor do que a capacidade preditiva dos modelos baseados no domínio do tempo. E, por isso, têm sido propostos por pesquisadores da área como uma alternativa aos modelos baseados no domínio do tempo. Entretanto, para chegar a uma conclusão sobre a superioridade desta classe de modelos é necessário avaliar a sua sensibilidade a variações do perfil operacional. Uma qualidade desejável dos modelos de confiabilidade de software é a de que sua capacidade preditiva não seja afetada por variações no perfil operacional de um software. Esta dissertação avalia, por meio de um experimento, o comportamento de dois modelos de confiabilidade de software que se baseiam na informação de cobertura do código: "Modelo Binomial Baseado em Cobertura" e "Modelo de Falhas Infinitas Baseado em Cobertura". O experimento aplica os modelos nos dados de falhas observados durante a execução de um programa em três perfis operacionais estatisticamente distintos. Adicionalmente, seis modelos de confiabilidade de software tradicionais são utilizados para estimar a confiabilidade do software utilizando os mesmos dados de falhas. Os modelos escolhidos foram: Musa-Okumoto, Musa Básico, Littlewood-Verral Linear, Littlewood-Verral Quadrático, Jelinski-Moranda e Geométrico. Os resultados mostram que a capacidade preditiva dos modelos "Modelo Binomial Baseado em Cobertura" e "Modelo de Falhas Infinitas Baseado em Cobertura" não é afetada com a variação do perfil operacional do software. O mesmo resultado não foi observado nos modelos de confiabilidade de software baseados no domínio do tempo, ou seja, a alteração do perfil operacional influencia a capacidade preditiva desses modelos. Um resultado observado, por exemplo, é de que nenhum dos modelos tradicionais pôde ser utilizado para estimar a confiabilidade do software aplicando os dados de falhas gerados por um dos perfis operacionais / Abstract: Several published studies indicate that the predictive ability of the software reliability models using test coverage information observed during the tests is better than the predictive ability of models based on time domain. And, therefore, have been proposed by researchers as an alternative to models based on time domain. However, to reach a conclusion about the superiority of this class of models is necessary to evaluate their sensitivity to variations in operational profile. A desirable quality of software reliability models is that their predictive ability is not affected by variations in the operational profile of a program. This dissertation analyzes by means of an experiment, the sensitivity of two software reliability models based on code coverage information: "Binomial Model Based on Coverage" and "Infinite Failure Model Based on Coverage". The experiment applies the models to data failures observed during the execution of a program according to three statistically distinct operational profiles. Additionally, six traditional software reliability models were used to estimate the reliability using the same software failure data. The models selected were: Musa-Okumoto, Musa Basic, Littlewood-Verrall Linear, Quadratic Littlewood-Verrall, Jelinski-Moranda and Geometric. The results show that the predictive ability of the models "Binomial Model Based on Coverage" and "Infinite Failure Model Based on Coverage" is not affected by varying the operational profile of the software. The same result was not observed in software reliability models based on time domain, i.e., changing the operational profile influences the predictive ability of these models. A result observed for example is that none of the traditional models could be used to estimate the software reliability using the fault data set generated by one of the operational profiles / Mestrado / Engenharia de Computação / Mestre em Engenharia Elétrica

Thesis: M.S., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 1979 / Includes bibliographical references. / by Han-Ngee Tan. / M.S. / M.S. Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science

The concept of load analogy is used in the elastic and elastic-plastic analysis of isotropic circular and annular plates undergoing moderately large deflection. The effects of the nonlinear terms of lateral displacement and the plastic strains are considered as additional fictitious lateral loads, edge moments, and in-plane forces acting on the plate. The solution of an elastic or elastic-plastic Von Karman type plate is hence reduced to a set of two equivalent elastic plate problems with small displacements, namely, a plane problem in elasticity and a linear elastic plate bending problem. The method of finite element is employed to solve the plane stress problem. The large deflection solutions are then obtained by utilizing the solutions of the linear bending problems through an iterative numerical scheme. The flow theory of plasticity incorporating a Von Mises layer yield criterion and the Prandtl-Reuss associated flow rule for strain hardening materials is employed in this approach.

No description available.

Rotating machines such as motors, generators, turbines, etc. are crucial mechanical components of modern industrial and power generation facilities. For proper functioning of these facilities during and after an earthquake, it is essential that the rotating machines in these facilities also function as desired. The dynamics of a rotating machine is quite complex. It is further complicated by the presence of earthquake induced base motions. The response spectrum methods, which are now commonly used for calculating seismic design response of civil structures, cannot be used as such for calculating the design response of rotating machines. In this thesis, a response spectrum method which can be applied to the rotating machines is developed. To develop the response spectrum approach, a generalized modal superposition method is utilized. The random vibration analysis is applied to incorporate the stochastic characteristics of the seismic inputs. The applicability of the proposed response spectrum approach is verified by a simulation study where fifty sets of acceleration time histories are used. The proposed method considers the fact that earthquake induced base motions have several components, including rotational inputs. To define the correlation between the rotational and translational input components of the excitation, the correlation matrix and a travelling seismic wave approaches are used. The numerical results are obtained to evaluate the effect of rotational input components on the response of a rotating machine. It is observed that the rotational components are important only when they are very strong. In actual practice, such strong rotational inputs are not expected to excite rotors which are either directly placed on ground or are placed in common buildings. In the proposed spectrum approach, nevertheless, the effect of rotational input components can be easily incorporated if the correlation between various excitation components is specified. / Master of Science

A micromechanics-based model for progressive failure analysis of laminated composite shell structures has been developed and implemented. The model couples a finite element model for nonlinear analysis of laminated shells with a micro mechanics elasticity solution for predicting failure and effective composite properties. The nonlinear laminate theory and finite element model are based on a third-order expansion of displacements through the thickness of the shell, thus allowing for both transverse normal and shearing deformations. The initiation and evolution of damage in the shell is modeled at the constituent (i.e., fiber, matrix, interphase) level using an elasticity solution for quasi-three-dimensional hygro-thermo-mechanical loading of continuous fiberreinforced composites. The model is used to predict failure in laminated composite structures and to study the effects of constituent properties (stiffness and strength) on structural behavior. / Ph. D.

Composite diaphragm strength and behavior were studied using non-linear finite element analysis. A total of 57 three panel diaphragm models were analyzed to failure. Parameters studied included beam size and orientation, panel dimension, connector type and distance, slab opening, yield plateau, and beam connection flexibility. Shear connector, deck-to-concrete interface, and beam connection were the components modeled non-linearly. Orthotropic behavior was used for the deck elements. 2-D and 3-D contours of concrete slab, steel deck and deck-to-concrete interfacial stresses and connector forces are presented to clearly show the behavior of the diaphragm in relation with the component behavior. Complete and incomplete connector force redistributions were observed and an expression of yield plateau length required to develop a complete connector force redistribution was developed. Expressions for diaphragm strength based on beam, beam connection and connector strength for both the complete and incomplete connector force redistribution cases were presented. The diaphragm strength predicted by the expression compared favorably with the finite element results. / Master of Science