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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

Modelagem e simula??o de um separador bif?sico com invers?o de fases induzida

Freitas, Hanniel Ferreira Sarmento de 05 July 2013 (has links)
Made available in DSpace on 2014-12-17T15:01:32Z (GMT). No. of bitstreams: 1 HannielFSF_DISSERT.pdf: 2655706 bytes, checksum: fff21ca883e2c0c137ef98496660b572 (MD5) Previous issue date: 2013-07-05 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The present work has the main goal to study the modeling and simulation of a biphasic separator with induced phase inversion, the MDIF, with the utilization of the finite differences method for the resolution of the partial differencial equations which describe the transport of contaminant s mass fraction inside the equipment s settling chamber. With this aim, was developed the deterministic differential model AMADDA, wich was admensionalizated and then semidiscretizated with the method of lines. The integration of the resultant system of ordinary differential equations was realized by means of a modified algorithm of the Adam-Bashfort- Moulton method, and the sthocastic optimization routine of Basin-Hopping was used in the model s parameter estimation procedure . With the aim to establish a comparative referential for the results obtained with the model AMADDA, were used experimental data presented in previous works of the MDIF s research group. The experimental data and those obtained with the model was assessed regarding its normality by means of the Shapiro-Wilk s test, and validated against the experimental results with the Student s t test and the Kruskal-Wallis s test, depending on the result. The results showed satisfactory performance of the model AMADDA in the evaluation of the MDIF s separation efficiency, being possible to determinate that at 1% significance level the calculated results are equivalent to those determinated experimentally in the reference works / O presente trabalho tem como objetivo estudar a modelagem e simula??o de um separador bif?sico com invers?o de fases induzida, o MDIF (Misturador Decantador ? Invers?o de Fases), por meio da utiliza??o do m?todo das diferen?as finitas para a resolu??o das equa??es diferenciais parciais que descrevem o transporte da fra??o m?ssica do contaminante no interior da c?mara de decanta??o do equipamento. Com esse intuito, foi desenvolvido o modelo determin?stico diferencial AMADDA, o qual foi admensionalizado e ent?o semidiscretizado atrav?s do m?todo das linhas. A integra??o do sistema de equa??es diferenciais ordin?rias resultante foi realizada atrav?s de um algoritmo modificado do m?todo de Adam-Bashfort-Moulton, e a rotina de otimiza??o estoc?stica de Basin-Hopping foi utilizada no procedimento de estima??o de par?metros do modelo. Com o intuito de estabelecer um referencial comparativo para a valida??o dos resultados obtidos com o modelo AMADDA, foram utilizados dados experimentais apresentados na literatura (FERNANDES JR, 2002; FERNANDES JR, 2006; MEDEIROS, 2008). Os resultados experimentais e aqueles obtidos com o modelo foram avaliados quanto ? sua normalidade por meio do teste de Shapiro-Wilk, e validados frente aos resultados experimentais atrav?s do teste t de Student e o o teste de Kruskal-Wallis, ? depender do resultado. Os resultados obtidos atrav?s do modelo AMADDA mostraram um desempenho satisfat?rio na determina??o da efici?ncia de separa??o do MDIF, sendo poss?vel determinar que, a um n?vel de signific?ncia de 1%, os resultados calculados s?o equivalentes ?queles determinados experimentalmente nos trabalhos de refer?ncia
2

Modelagem matem?tica de controle ?timo para vacina??o contra a gripe H1N1 / Mathematical modeling of optimal control for vaccination against H1N1 influenza

Souza, Pablo Amauri Carvalho de Ara?jo e 13 June 2016 (has links)
Submitted by Celso Magalhaes (celsomagalhaes@ufrrj.br) on 2017-05-19T12:03:19Z No. of bitstreams: 1 2016 - Pablo Amauri Carvalho de Ara?jo e Souza.pdf: 3429164 bytes, checksum: c1da6eb8bb41fc96de0b7e5ca2a9570f (MD5) / Made available in DSpace on 2017-05-19T12:03:19Z (GMT). No. of bitstreams: 1 2016 - Pablo Amauri Carvalho de Ara?jo e Souza.pdf: 3429164 bytes, checksum: c1da6eb8bb41fc96de0b7e5ca2a9570f (MD5) Previous issue date: 2016-06-13 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / This work highlights the importance of well administrated vaccination as prophylactic activity, making it a key element of mathematical modeling about the spreading of an infection by Influenza H1N1 virus in a human population. The model counts with Optimal Control theory to achieve a vaccination strategy that balance infection?s prevention and your own cost in a hypothetical population exposed to a virus. The numerical solutions of ordinary differential equations systems generated by model is given via Finite Difference Method, that reveals the populational dynamics during the time while the vaccine is distributed, in various different situations of virus exposition and vaccination cost. / Este trabalho ressalta a import?ncia da vacina??o bem administrada como atividade profil?tica, tornando-a elemento chave da modelagem matem?tica do espalhamento da infec??o pelo v?rus Influenza H1N1 em uma popula??o humana. O modelo conta com a teoria de Controle ?timo para alcan?ar uma estrat?gia de vacina??o, que equilibre a preven??o da infec??o e seu pr?prio custo em uma popula??o hipot?tica exposta ao v?rus. As solu??es num?ricas dos sistemas de equa??es diferenciais ordin?rias gerados pelo modelo ficam a cargo do M?todo das Diferen?as Finitas, revelando a din?mica populacional no per?odo de tempo em que a vacina ? distribu?da, em distintas situa??es de exposi??o ao v?rus e custo da vacina??o.
3

An?lise de modelo conceitual de simula??o de fluxo hidrogeol?gico por meio do m?todo das diferen?as finitas no munic?pio de Te?filo Otoni - MG

Aguiar, Victor Luiz Batista 15 March 2017 (has links)
Submitted by Raniere Barreto (raniere.barros@ufvjm.edu.br) on 2018-05-07T19:57:19Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) victor_luiz_batista_aguiar.pdf: 2508647 bytes, checksum: 87d9596e1cf8e04b90b12aa373fa4748 (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2018-05-08T12:30:45Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) victor_luiz_batista_aguiar.pdf: 2508647 bytes, checksum: 87d9596e1cf8e04b90b12aa373fa4748 (MD5) / Made available in DSpace on 2018-05-08T12:30:45Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) victor_luiz_batista_aguiar.pdf: 2508647 bytes, checksum: 87d9596e1cf8e04b90b12aa373fa4748 (MD5) Previous issue date: 2017 / A crescente demanda pela utiliza??o de recursos h?dricos em nossa sociedade faz com que seja necess?ria a amplia??o dos meios de capta??o de ?gua. As ?guas subterr?neas surgem como alternativa ? capta??o convencional, tendo em vista que o armazenamento da ?gua nas camadas inferiores do solo garanta a manuten??o da qualidade deste recurso, uma vez que passam por processos naturais de filtra??o. Nesse sentido, a caracteriza??o dos sistemas aqu?feros por meio de modelagem matem?tica surge como ferramenta de aux?lio na compreens?o do fluxo subterr?neo local. A presente pesquisa tem como principal objetivo analisar o comportamento hidrogeol?gico do munic?pio de Te?filo Otoni - MG, com base em simula??es oriundas de modelos conceituais, pelo m?todo das diferen?as finitas. Por meio de simula??o de propriedades influentes no transporte h?drico como taxa de recarga, vaz?o de bombeamento de po?os e condutividade hidr?ulica, foi poss?vel observar as varia??es nos valores m?ximos e m?nimos de carga hidr?ulica em pontos discretizados nos limites do modelo conceitual proposto, auxiliando assim no entendimento dos resultados obtidos. / Disserta??o (Mestrado Profissional) ? Programa de P?s-Gradua??o em Tecnologia, Sa?de e Sociedade, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2017. / The growing demand for the use of water resources in our society makes it necessary to expand the means of abstraction of water. Groundwater emerges as an alternative to conventional abstraction, owing to the storage of water in the lower layers of the soil ensures the maintenance of the quality of this resource, since they undergo natural filtration processes. In this sense, the characterization of the aquifer systems through mathematical modeling appears as a tool to aid in the understanding of the local underground flow. The present research has as main objective to analyze the hydrogeological behavior of Te?filo Otoni - MG, based on simulations derived from conceptual models, by the finite difference method. By means of simulation of influent properties in the water transport as recharge rate, well pumping rate and hydraulic conductivity it was possible to observe the variations in the maximum and minimum values of hydraulic head in discretized points within the limits of the proposed conceptual model, thus helping in the understanding of the results obtained.
4

Aplica??o do m?todo das diferen?as finitas energ?ticas na modelagem do concreto refor?ado com fibras curtas de a?o sob flex?o

Neves, J?lia Barbosa 24 September 2013 (has links)
Submitted by Verena Bastos (verena@uefs.br) on 2015-08-05T21:29:18Z No. of bitstreams: 1 NEVES_JB_2012_R2.pdf: 2142681 bytes, checksum: 2f1f8d4679734685ccd9edf621f7b8c4 (MD5) / Made available in DSpace on 2015-08-05T21:29:18Z (GMT). No. of bitstreams: 1 NEVES_JB_2012_R2.pdf: 2142681 bytes, checksum: 2f1f8d4679734685ccd9edf621f7b8c4 (MD5) Previous issue date: 2013-09-24 / Funda??o de Amparo ? Pesquisa do Estado de S?o Paulo - FAPESP / The prediction of the reinforced concrete beams behavior under bending is essential to design these elements. Usually the models do not incorporate the concrete stress contribution, which may underestimate the structural element strain that use steel fiber reinforced concrete (SFRC) under permanent or temporary loads. This work presents a variational formulation based on the finite difference energy method (EFDM) in predicting the flexural behavior of concrete beams reinforced, that uses SFRC. The proposed model uses the classical lamination theory (CLT) with a damage model (Mazars, 1984) applied to the SFRC. The reinforcement was considered as a layer of a perfect elastic-plastic material. Comparing the load-displacement numerical results with those of the literature to reinforced concrete beams demonstrates the consistency of the proposed model. / A previs?o do comportamento de vigas de concreto armado sob flex?o ? fundamental para o adequado dimensionamento destes elementos. Usualmente, os modelos n?o incorporam a contribui??o do concreto tracionado, o que pode subestimar as deforma??es no elemento estrutural que utilizem o concreto refor?ado com fibras (CRFA) sob cargas de curta e longa dura??o. No presente trabalho ? apresentada uma formula??o variacional com base no m?todo das diferen?as finitas energ?ticas (MDFE) para a previs?o do comportamento ? flex?o de vigas de concreto simples ou armado refor?adas com fibras de a?o. O modelo proposto combina a teoria cl?ssica de laminados (TCL) com um modelo de dano (Mazars, 1984) aplicado ao concreto. O refor?o (armadura longitudinal) foi considerado como uma l?mina de um material elasto-pl?stico perfeito. A compara??o dos resultados num?ricos com resultados encontrados na literatura para vigas de concreto armado, em termos de cargadeslocamento, demonstra a coer?ncia do modelo proposto.

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