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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

COMPUTATIONAL INVESTIGATION OF TRANSMURAL DIFFERENCES IN LEFT VENTRICULAR CONTRACTILITY AND HYDROGEL INJECTION TREATMENT FOR MYOCARDIAL INFARCTION

Wang, Hua 01 January 2017 (has links)
Heart failure (HF) is one of the leading causes of death and impacts millions of people throughout the world. Recently, injectable hydrogels have been developed as a potential new therapy to treat myocardium infarction (MI). This dissertation is focused on two main topics: 1) to gain a better understanding the transmural contractility in the healthy left ventricle (LV) wall and 2) investigate the efficacy of the hydrogel injection treatment on LV wall stress and function. The results indicate that a non-uniform distribution of myocardial contractility in the LV wall provide a better representation of normal LV function. The other important study explored the influence altering the stiffness of the biomaterial hydrogel injections. These results show that a larger volume and higher stiffness injection reduce myofiber stress the most and maintaining the wall thickness during loading. The computational approach developed in this dissertation could be used in the future to evaluate the optimal properties of the hydrogel. The last study used a combination of MRI, catheterization, finite element (FE) modeling to investigate the effects of hydrogel injection on borderzone (BZ) contractility after MI. The results indicate that the treatment with hydrogel injection significantly improved BZ function and reduce LV remodeling, via altered MI properties. Additionally, the wall thickness in the infarct and BZ regions were significantly higher in the treated case. Conclusion: hydrogel injection could be a valuable clinical therapy for treating MI.
2

Computational Investigation of Injectable Treatment Strategies for Myocardial Infarction

Wang, Hua 01 January 2014 (has links)
Heart failure is an important medical disease and impacts millions of people throughout the world. In order to treat this problem, biomaterial injectable treatment injected into the myocardium of the failing LV are currently being developed. Through this treatment, the biomaterial material injections can reduce wall stresses during the cardiac remodeling process. By using computational techniques to analyze the effects of a treatment involving the injection of biomaterial material into the LV after MI, the material parameters of the hydrogel injections can be optimized. The results shows that the hydrogel injections could reduce the global average fiber stress and the transmural average stress seen from optimization. These results indicated that the hydrogel injections could influence the stiffness in passive LV tissue, but there is still need for more research on the active part of ventricular contraction. Conclusion: hydrogel injection is a viable way to alter ventricular mechanical properties.
3

Optimalizace vybraných parametrů pro návrh objektů s nízkou energetickou náročností / Optimization of selected parameters for the design of buildings with low energy consumption

Jarošová, Petra Unknown Date (has links)
The doctoral thesis pays attention to the system approach to the nonstationary computational modelling of heat transfer for energy saving buildings. The created computational tool supports the optimization of selected design parameters.
4

Formation Flight and Deformation Operational Trajectory Planning for Aircraft System

Haris, Muhammad 11 1900 (has links)
This thesis presents a comprehensive framework and a study for trajectory optimization based on the patterned formation flying of the aircraft system as well as the maneuvers for deforming the configured and aligned aerial vehicles with safe mode criteria considerations while subjected to typical environmental requirements of aerial-flying zones. The elementary trajectory problem of a simple dynamical point-mass system of the aircraft is mathematically formulated and converted into a simulation version of mathematical programming as finite horizon planning and fixed arrival time planning strategies as an optimization problem. The methodology of the designed framework is mainly concerned with the safer path planning of the aircraft system with testing on all the probable feasibility and safety constraints to incorporate into a mathematical programming design of a collision-free and optimal trajectory characterization. The imperative notion is to create a configurational pattern of the aircraft system based on their creation of wingtip vortices. Flying the aircraft in formation lessen the fuel consumption as well as increase the time efficiency. The aircraft formation is arranged and optimized for safe trajectories during flight operations and for reduction of the carbon footprint of the whole system. Furthermore, deformation maneuvers are incorporated to complete the aircraft planning system by allowing the possibility of safely disassembling the formation for emergency breakout and exit sequences.
5

Método computacional para elaboração de projetos eletromecânicos de redes de distribuição de energia elétrica com condutores de alumínio Nu

Carvalho, Denner Monteiro de 28 September 2017 (has links)
Submitted by Marlene Santos (marlene.bc.ufg@gmail.com) on 2017-11-17T16:18:59Z No. of bitstreams: 2 Dissertação - Denner Monteiro de Carvalho - 2017.pdf: 49512193 bytes, checksum: dce0c13146977219335b29250e4960d7 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2017-11-20T10:11:34Z (GMT) No. of bitstreams: 2 Dissertação - Denner Monteiro de Carvalho - 2017.pdf: 49512193 bytes, checksum: dce0c13146977219335b29250e4960d7 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-11-20T10:11:34Z (GMT). No. of bitstreams: 2 Dissertação - Denner Monteiro de Carvalho - 2017.pdf: 49512193 bytes, checksum: dce0c13146977219335b29250e4960d7 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-09-28 / The present work presents the development of a computational tool for the optimization of processes in the elaboration of electromechanical projects of conventional electricity distribution networks. The current process of elaboration of distribution network projects that has significant topographical interferences is slow and depends on software with a technological lag that requires post processing of the data to generate the final project, besides demanding specific technical knowledge and too much elaboration time. This elaboration time, as well as the errors occurred in the post-processing stage, hinder the approval process of the projects in the electric power concessionaires, and delay the connection of final consumers. For modeling the process, the typologies of the terrain where the network path is to be determined through surveys of the topographic data are verified first. Afterwards, mechanical forces and stresses are observed in each type of electromechanical structure, defining the minimum mounting distances in compliance with related technical norms, as well as incident variables such as wind speed and mechanical variations of the conductors during the operation. The modeling of the decision variables is applied a recursive heuristic method with the application of the Hill Climbing optimization method, which sweeps the entire line defined by topography, performing the mechanical evaluations and calculations with the optimization of technical budget criteria, generating uniform solutions and Automated. The tool obtained is developed in Web platform with friendly interface and updated, and can be used through any browser. The software, besides providing the elaboration of the project with embedded normative criteria, can be easily used for project analysis, providing integrated visualization of the planialtimetric profiles through Google Maps, optimizing the process of visual evaluation. / O presente trabalho apresenta o desenvolvimento de um método computacional destinado à otimização de processos na elaboração de projetos eletromecânicos de redes de distribuição convencional de energia elétrica. O processo atual de elaboração de projetos de redes de distribuição que possui interferências topográficas é lento e depende de softwares com defasagem tecnológica que necessitam de pós processamento dos dados para gerar o projeto final, além de demandar conhecimento técnico específico e demasiado tempo de elaboração. Esse tempo de elaboração, bem como os erros ocorridos na etapa de pós processamento, dificultam o processo de aprovação dos projetos nas concessionárias de energia elétrica, e atrasam a ligação dos consumidores finais. Para modelagem do processo, são verificados primeiramente as tipologias do terreno onde se deseja definir o caminhamento da rede através de levantamentos dos dados topográficos. Após, são observados os esforços e solicitações mecânicas pontualmente em cada tipo de estrutura eletromecânica, definindo as distâncias mínimas de montagem em observância às normas técnicas relacionadas, e também, variáveis incidentes como a velocidade do vento e variações mecânicas dos condutores durante a operação. Realizada a modelagem das variáveis de decisão é aplicado um método heurístico recursivo com a aplicação do método de otimização Hill Climbing, que varre toda a linha definida pela topografia, realizando as avaliações e cálculos mecânicos com a otimização de critérios técnicos orçamentários, gerando soluções uniformizadas e automatizadas. O método computacional é desenvolvido em plataforma Web com interface amigável e atualizada, podendo ser utilizada através de um navegador qualquer. O software além de proporcionar a elaboração do projeto com critérios normativos embutidos, pode ser facilmente utilizada para análise de projetos, proporcionando visualização integrada dos perfis planialtimétricos através Google Maps, otimizando o processo de avaliação visual.

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