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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.
351

Estudo do fenômeno da auto-intersecção em um anel anisotrópico / Study of the self-intersection anomaly in an anisotropic ring

Jesús Antonio García Sánchez 17 November 2008 (has links)
Estuda-se numericamente uma placa circular homogênea com furo centrado sob estado plano de deformação. A placa está fixa ao longo do contorno interno e está sob compressão radial uniforme ao longo do contorno externo. O material da placa é elástico-linear e anisotrópico. Apresenta-se a solução analítica do problema, a qual satisfaz as equações governantes de equilíbrio, no contexto da elasticidade linear clássica. Esta solução prediz o comportamento espúrio da auto-intersecção em uma região central da placa. Para evitar este comportamento, utiliza-se uma teoria que propõe encontrar um campo de deslocamento que minimize a energia potencial total do corpo sujeito à restrição de injetividade local para o campo da deformação correspondente. Esta teoria, juntamente com o método das penalidades interiores, permite encontrar uma solução numérica que preserva a injetividade. Esta solução corresponde a um campo de deslocamento radialmente simétrico. Estuda-se a possibilidade de encontrar uma solução rotacionalmente simétrica do problema restrito, em que o campo de deslocamento possua as componentes radial e tangencial, ambas funções somente do raio. Os resultados desta última modelagem mostram que a componente tangencial é nula, indicando que o campo de deslocamento é, de fato, radialmente simétrico. Mostra-se também que a solução do problema do anel converge para a solução do problema de um disco sem furo à medida que o raio do furo tende a zero. / This work concerns a numerical study of a homogeneous circular plate with a centered hole that is under a state of plane strain. The plate is fixed at its inner surface and is under uniform radial compression at its outer surface. The plate is linear, elastic, and anisotropic. An analytical solution for this problem, which satisfies the governing equations of equilibrium, is presented in the context of classical linear elasticity. This solution predicts the spurious behavior of self-intersection in a central region of the plate. To avoid this behavior, a constrained minimization theory is used. This theory concerns the search for a displacement field that minimizes the total potential energy of the body, which is a quadratic functional from the classical linear theory, subjected to the constraint of local injectivity for the associated deformation field. This theory together with an interior penalty method and a standard finite element methodology yield a numerical solution, which is radially symmetric, that preserves injectivity. Here, it is investigated the possibility of finding a rotationally symmetric solution to the constrained problem; one for which the associated displacement field has radial and tangential components, which are both functions of the radius only. The numerical results show, however, that the tangential component is zero. It is also shown that, as the radius of the hole tends to zero, the corresponding sequence of solutions tends to the solution of a solid disk.
352

Subsídios para a minimização dos resíduos de serviços de saúde gerados na unidade hospitalar da UNIMED na cidade de Rio Claro - SP / Minimization of medical waste in the hospital of Unimed in the city Rio Claro - SP

Marcio Milani Marques Lima 24 August 2001 (has links)
As proposições deste trabalho tiveram como objetivo fundamental orientar e/ou melhorar um sistema organizado de RSS (Resíduos de Serviços de Saúde), em qualquer estabelecimento gerador, com a finalidade de controlar, reduzir com segurança e economia, os riscos associados aos RSS. Para o desenvolvimento de tais aspectos, foi escolhido o Hospital Unimed, unidades I e II, por ser de porte médio. No desenvolvimento do trabalho, foram considerados três aspectos fundamentais: a organização do sistema de manuseio dos resíduos sólidos, os aspectos técnicos-operacionais, os recursos humanos necessários, determinando assim responsabilidades bem definidas com o intuito de reduzir ao máximo os riscos para a saúde e meio ambiente, atendendo as especificações exigidas pela legislação e colaborando assim com toda a comunidade para uma qualidade de vida cada vez melhor. / The proposals of this work had as fundamental objective to orientate and/or to improve a system organized by HSW (HeaIth Service Wastes), in any generator establishment generated with the aim of controlling, reducing with insurance and economy the risks linked to HSW. To deveIopment of such aspects, Hospital UNIMED was chosen, Units I and lI, because it is a medium size hospital. In the development of this work, three fundamentaIs aspects were considered: The organization of the handIe system of the solids wastes, technical - operational aspects, the human resources necessaries, so determining well defined responsibiIities with the objective of reducing at rnaximum the health and environmentaI risks, taking into consideration the specifications demanded by the legislation and collaborating with all the community for a much better quality of life.
353

Minimização e reuso de águas em indústrias sucroalcooleiras: estudo de caso / Minimization and reuse of water in sugar and ethanol industries: a case study

Sônia Maria Kesserlingh 11 October 2002 (has links)
Em conseqüência da constatação do consumo elevado de águas nas indústrias sucroalcoleiras, gerando efluentes líquidos que impactam o meio ambiente, considerando os avanços na implantação da cobrança pelo uso da água, este trabalho aborda várias alternativas de minimização e reuso de águas nas indústrias sucroalcooleiras, objetivando a redução da poluição na fonte e minimização da captação de água superficial, reutilizando os efluentes dentro do processo produtivo. Também são apresentados os resultados de um estudo de caso realizado em uma indústria, na qual foi realizada uma pesquisa do processo industrial, para determinar o consumo de água e a qualidade de efluentes e propor alternativas para minimização da captação de água e geração de efluentes. / It is a fact that the sugar and ethanol industry in Brazil has a high level of water consumption and consequent production of effluents, with a negative impact to the environment. Also, the environmental legislation indicates a continuous raise in the charge for the usage of water from natural sources. As a consequence of the present situation, this work brings up several alternatives for the minimization and reuse of water at sugar and ethanol industries, aiming the reduction of pollutants at their source and the minimization of water uptake from the available supplies, by reusing the effluents inside the production process itself. It is also presented the results from a case study carried out in an industry where the production process was analyzed in the point-of-view of water usage and effluent generation. Alternatives for water uptake and effluent generation minimization are therefore proposed.
354

Caracterização do nível crítico para as soluções de energia mínima de uma classe de problemas elípticos semi-lineares

Belchior, Pedro 01 March 2013 (has links)
Submitted by isabela.moljf@hotmail.com (isabela.moljf@hotmail.com) on 2016-12-19T12:23:36Z No. of bitstreams: 1 pedrobelchior.pdf: 465178 bytes, checksum: 997aa94857f2f7478cb38dc9980463d3 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-02-02T11:10:14Z (GMT) No. of bitstreams: 1 pedrobelchior.pdf: 465178 bytes, checksum: 997aa94857f2f7478cb38dc9980463d3 (MD5) / Made available in DSpace on 2017-02-02T11:10:14Z (GMT). No. of bitstreams: 1 pedrobelchior.pdf: 465178 bytes, checksum: 997aa94857f2f7478cb38dc9980463d3 (MD5) Previous issue date: 2013-03-01 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / As soluções de energia mínima são de nidas como as soluções que indicam valor ín fimo para imagem do funcional energia associado a uma classe de problemas variacionais não lineares −∆u = g(u) u ∈ H1(RN) Oobjetivodestetrabalhoémostrarqueatravésdassoluçõesdeenergiamínimadaequação não linear acima, o valor do passo da Montanha sem a condição de Palais Smaile é um ponto crítico. Para isto provaremos que sob certas hipóteses para a função g e sob um vínculo é possível obter uma solução positiva para o problema acima, esfericamente simétrica e decrescente com o raio. Em seguida mostra-se que a solução sujeita a esse vínculo é a que possui o menor valor no funcional energia dentre todas as soluções do problema acima aplicadas no mesmo funcional. Neste contexto, garante-se a existência de pelo menos uma solução de energia mínima. Os resultados citados foram estudados em [2] e [1]. / The least energy solutions are de ned as solutions that indicate infi mum value to the energy functional image associated with a class of nonlinear variational problems −∆u = g(u) u ∈ H1(RN) The objective of this work is to show that through least energy solutions of nonlinear equation above, the Mountain pass value without the Palais Smale condition is critical point. For this, we will prove that under certain hypotheses on the function g and under a constraint assumption is possible to obtain a positive solution for the above problem, spherically symmetric and decreasing with the radius. Then the solution of the problem subject to this constraint has the lowest value in the energy functional among all solutions of the above problem applied in the same functional. In this context, it guarantee the existence of at least one solution of the least energy. The above results were obtained in [2] and [1]. Key Words: Least Energy, Mountain Pass, Minimization, Minimum of the Action.
355

Caracterização do nível crítico para as soluções de energia mínima de uma classe de problemas elípticos semi-lineares

Belchior, Pedro 01 March 2013 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-05-29T15:09:36Z No. of bitstreams: 1 pedrobelchior.pdf: 465178 bytes, checksum: 997aa94857f2f7478cb38dc9980463d3 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-05-29T19:48:54Z (GMT) No. of bitstreams: 1 pedrobelchior.pdf: 465178 bytes, checksum: 997aa94857f2f7478cb38dc9980463d3 (MD5) / Made available in DSpace on 2017-05-29T19:48:54Z (GMT). No. of bitstreams: 1 pedrobelchior.pdf: 465178 bytes, checksum: 997aa94857f2f7478cb38dc9980463d3 (MD5) Previous issue date: 2013-03-01 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / As soluções de energia mínima são definidas como as soluções que indicam valor ínfimo para imagem do funcional energia associado a uma classe de problemas variacionais não lineares -Δu = g(u) u ∈ H1(RN). O objetivo deste trabalho é mostrar que através das soluções de energia mínima da equação não linear acima, o valor do passo da Montanha sem a condição de Palais Smaile é um ponto crítico. Para isto provaremos que sob certas hipóteses para a função g e sob um vínculo é possível obter uma solução positiva para o problema acima, esfericamente simétrica e decrescente com o raio. Em seguida mostra-se que a solução sujeita a esse vínculo é a que possui o menor valor no funcional energia dentre todas as soluções do problema acima aplicadas no mesmo funcional. Neste contexto, garante-se a existência de pelo menos uma solução de energia mínima. Os resultados citados foram estudados em [2] e [1]. / The least energy solutions are defined as solutions that indicate infimum value to the energy functional image associated with a class of nonlinear variational problems -Δu = g(u) u ∈ H1(RN). The objective of this work is to show that through least energy solutions of nonlinear equation above, the Mountain pass value without the Palais Smale condition is critical point. For this, we will prove that under certain hypotheses on the function g and under a constraint assumption is possible to obtain a positive solution for the above problem, spherically symmetric and decreasing with the radius. Then the solution of the problem subject to this constraint has the lowest value in the energy functional among all solutions of the above problem applied in the same functional. In this context, it guarantee the existence of at least one solution of the least energy. The above results were obtained in [2] and [1].
356

Despacho ótimo de pequenas centrais hidrelétricas para minimização da contratação do suprimento / Optimal dispatch of small hydro plants for the minimization of contract supply

Malaquias, Luciano 13 September 2013 (has links)
This Master s Dissertation presents the development of a methodology to optimize the modulation of dispatch of Small Hydro Power Plants (SHPs). The main objective is to minimize the cost of supplying contracts, which comprise both the contracts of energy and the contracts of the use of the transmission and distribution systems by the power utilities. The application of the proposed methodology is technically subject to the operative constraints of the SHPs as well as to the constraints of the substations located in the connection points among utilities and the transmission system. The methodology is also based on the regulation of the Brazilian electrical system. The flow duration curves are taken in order to optimize the dispatch and the load curves from periods of the highest annual demands are considered to represent the distribution system behavior. We used the technique of genetic algorithms to the simulations with real data, from a Brazilian power utility are applied in order to analyze the economic and technical results and then proven the methodology. / Esta dissertação apresenta o desenvolvimento de uma metodologia para a otimização da modulação do despacho de Pequenas Centrais Hidrelétricas (PCHs), com objetivo de minimizar os custos da contratação do suprimento, que compreende a contratação da energia e a contratação do uso dos sistemas de transmissão e ou distribuição, para as concessionárias de distribuidoras de energia elétrica. A aplicação da metodologia proposta, tecnicamente, está sujeita ao atendimento das restrições operativas das PCHs, bem como, das subestações localizadas no ponto de conexão das distribuidoras com a rede básica. A metodologia leva em consideração a regulação do setor elétrico. Para a otimização do despacho, é considerada a vazão afluente do aproveitamento hidrelétrico das PCHs, obtida a partir da curva de permanência de vazões. Representando o comportamento do sistema de distribuição foi usada a curva de carga, no período em que foi registrada a maior demanda anual. Para validação da metodologia, foi utilizada a técnica de algoritmos genéticos para as simulações com dados reais, de uma distribuidora do sul do Brasil foram utilizados e os resultados técnicos e econômicos foram comprovados.
357

Thermodynamic optimization of sustainable energy system : application to the optimal design of heat exchangers for geothermal power systems

Yekoladio, Peni Junior 08 July 2013 (has links)
The present work addresses the thermodynamic optimization of small binary-cycle geothermal power plants. The optimization process and entropy generation minimization analysis were performed to minimize the overall exergy loss of the power plant, and the irreversibilities associated with heat transfer and fluid friction caused by the system components. The effect of the geothermal resource temperature to impact on the cycle power output was studied, and it was found that the maximum cycle power output increases exponentially with the geothermal resource temperature. In addition, an optimal turbine inlet temperature was determined, and observed to increase almost linearly with the increase in the geothermal heat source. Furthermore, a coaxial geothermal heat exchanger was modeled and sized for minimum pumping power and maximum extracted heat energy. The geofluid circulation flow rate was also optimized, subject to a nearly linear increase in geothermal gradient. In both limits of the fully turbulent and laminar fully-developed flows, a nearly identical diameter ratio of the coaxial pipes was determined irrespective of the flow regime, whereas the optimal geofluid mass flow rate increased exponentially with the Reynolds number. SeveORCs were observed to yield maximum cycle power output. The addition of an IHE and/or an Oral organic Rankine Cycles were also considered as part of the study. The basic types of the FOH improved significantly the effectiveness of the conversion of the available geothermal energy into useful work, and increased the thermal efficiency of the geothermal power plant. Therefore, the regenerative ORCs were preferred for high-grade geothermal heat. In addition, a performance analysis of several organic fluids was conducted under saturation temperature and subcritical pressure operating conditions of the turbine. Organic fluids with higher boiling point temperature, such as n-pentane, were recommended for the basic type of ORCs, whereas those with lower vapour specific heat capacity, such as butane, were more suitable for the regenerative ORCs. / Dissertation (MEng)--University of Pretoria, 2013. / Mechanical and Aeronautical Engineering / unrestricted
358

Negative impacts of illegal waste dumping in Nelson Mandela Bay Municipality

Mralaza, Phumelele David January 2012 (has links)
South Africa is confronted by waste management challenges and the need to redress environmentally acceptable waste management practices. In seeking to address this challenge, the South African government has introduced waste management legislation, policies and strategies. Despite the legislation, policies and strategies on waste management, illegal waste dumping continues to exist as a major challenge in particular for the Nelson Mandela Bay Municipality. This study focuses on illegal waste dumping in Nelson Mandela Bay Municipality which negatively impacts on development. The study seeks to make recommendations which will assist the Nelson Mandela Bay Municipality to improve its waste management services. This study involved a community participatory approach by communities in Motherwell, New Brighton and Gelvandale. The research follows a mixed method approach, employing both qualitative and quantitative approach. A Public Perception Survey is used as a method of data collection aimed at determining the present public opinions regarding the waste management services currently offered by the Nelson Mandela Bay Municipality (NMBM). The study found that despite interventions by the NMBM to address illegal dumping, the problem continues to exist. Poor service provision by the NMBM in terms of waste collection services combined with the lack of awareness of the community‟s responsibility towards the cleanliness of its communities leads to littering and illegal dumping of waste by communities. The NMBM is not effective in the planning, coordination and implementation of its waste management services. Recommendations have been presented with regard to how effective waste management services in NMBM can be enhanced.
359

Automatizace dokumentů jako nástroj minimalizace rizik / Document Automation as a Risk Minimization Tool

Roch, Eduard January 2020 (has links)
This diploma thesis deals with the issues of risks in document creation processes and the possibilities of their minimization through the implementation of document automation tools. The thesis identifies the motives and goals of three major companies in the Czech Republic which have decided to implement a system for document automation Legito. Using the FMEA method, this thesis demonstrates the influence of document automation in minimizing identified risk incorporated with document creation. Furthermore, the thesis deals with the analysis of expected risks associated with the implementation of the document automation system and its subsequent adoption by end-users. From the obtained information, the author of the thesis formulates a general process of implementing document automation systems, which defines the various aspects necessary for the successful deployment of the document automation system in companies.
360

Simulace řízení asynchronního motoru s ohledem na vysokou účinnost / Simulation of induction machine control methods with respect to maximum efficiency

Hanzlíček, Martin January 2021 (has links)
The diploma thesis deals with the simulation of induction motor control with respect to high efficiency. The theory of an induction motor is described here, with emphasis on its losses. Scalar and vector control are also described here. Vector control is optimized for higher efficiency. Subsequently, the creation of a model in the program đť‘€đť´đť‘‡ đťżđť´đťµâ’𝑆𝑖𝑚𝑢𝑙𝑖𝑛𝑠is described here, for the comparison of scalar and vector control with optimization.

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