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Published: 10 December 2022
Last updated: 28 January 2023

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1

Chan, Danny. "The chemistry of platinum complexes and hydrosilation." Thesis, University of York, 1999. http://etheses.whiterose.ac.uk/14173/.

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This thesis describes the study of a series of platinum complexes, with particular emphasis towards hydrosilation. Platinum bis(phosphine) azodicarbonyl complexes Pt(PRI 3)2(R20CNNCOR2) (RI = Ph, Me; R2 = Ph, Me, OEt, Pri) were synthesised and studied. Multinuclear NMR spectroscopy on Pt(PRI3)2(R20CNNCOR2) revealed that the dicarbonyl substituted azo ligand is co-ordinated asymmetrically, consistent with a five membered, Pt-N-N-C-O ring. The crystal structure of Pt(PPh3)2(Pri02CNNC02Pri) shows that the co-ordination sphere of platinum is essentially square planar and co-planar with the five-membered, Pt(1)-0(1)-C(5)-N(2)-N(1) ring. The Pt(PRI 3)lR20CNNCOR2) complexes show sensitivity towards chlorinated solvents (CH2CI2, CHCI3) under photolysis conditions forming the corresponding platinum bis(phosphine) dichloride complexes; the same products are formed in a slower thermal reaction but only for complexes with azodicarboxylate ligands. Complexes with azodicarboxylate ligands also react photochemically with ethylene in ds-THF yielding Pt(PPh3)2(C2H4) but the azodiacyl analogues are inert in this respect. Azodicarboxylate compounds R02CNNC02R (R = Et, Pri, But) are inhibitors of the catalytic activity of [(Pt {174 _(CH2=CHSiMe2hO }h {.u-( CH2=CHSiMe2)20}] for the hydrosilation reaction. The inhibited species can be decomposed thermally or photoch~mically to give active hydrosilation catalysts. It was found that the bulky azo compound But02CNNC02But was the least effective inhibitor of [(Pt{ 174 - '(CH2=CHSiMe2hO} )2(P-( CH2=CHSiMe2)20)]. The photochemistry of platinum bis(phosphine) malonates and phthalates was found to be limited, and their reactivities were much lower compared to the analogous oxalate complexes. Silyl hydride complexes, cis-Pt(PCY3)2(H)(SiR3), were synthesised from the reaction of Pt(PCY3)2 and the corresponding silane. These complexes were undergo dynamic exchange in solution. Two exchange processes were identified; the first involves mutual phosphine exchange, i.e. positional interchange between the hydride and the silyl ligands. The second process occurs at higher temperatures (above 290 K) and involves the elimination and re-addition of the silane ligand HSiR3. Thermodynamic and activation parameters are obtained for cis-Pt(PCY3)2(SiR3) (R = Ph, SiR3 = SiMe2CH2CH=CH2, SiMe2Et). The reaction of Pt(PCY3)2 with the disilane HSiMe2(l,2-C6~)SiMe2H is thought to form a Pt(IV) bis(silyl) dihydride trigonal bipyramidal species of the form, Pt(PCY3)(H)2[SiMe2(1,2-C6~)SiMe2]' where the hydride ligands are in the axial positions. All of the platinum silyl hydride complexes studied degrade thermally to form trans-Pt(PCY3)2(H)2 at, or above, room temperature.
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2

Matzner, Robert Allan. "Characterization of aza-arene transport in saturated porous media." Diss., The University of Arizona, 1993. http://hdl.handle.net/10150/191179.

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Several factors which affect the transport of pyridine, quinoline and acridine (aza-arenes) in saturated porous media were investigated in laboratory experiments in order to provide data for input into coupled models that may be applied to predicting the fate of these compounds in groundwater. The effect of pH and ligand type and concentration on acridine solubility was studied in a series of batch and pH-stat experiments. There was a decrease in acridine solubility below the compound's pKₐ due to acridine/ligand precipitate formation. The reaction stoichiometry and solute/sorbent interactions of aza-arene adsorbed to porous silica were determined from batch adsorption and Raman spectroscopy experiments. The neutral aza-arene was hydrogen bonded to surface sites above the compound's pKₐ and there was a cation/ClO₄⁻ complex interacting with surface sites through dipole-dipole interactions below the pKₐ of the compound. The effect of pH, temperature, ligand type, average linear velocity and initial aqueous phase solute concentration on the adsorption of aza-arenes to porous silica was investigated in a series of column experiments. The extent of adsorption followed the trend pyridine < quinoline < acridine due to greater overlap of the molecule with adsorption sites as the number of rings increases. The extent of adsorption was greater below the compound's pKₐ than above because the complex was able to optimize its orientation with the surface. The extent of adsorption of neutral acridine was enhanced when carbonate was used as a buffer relative to phosphate due to carbonate's more exothermic hydration enthalpy. The isotherms were non-linear above and below the pKₐ of acridine. The enthalpy of the adsorption reaction was less exothermic below the compound's pKₐ than above due to the stronger hydrogen bonds formed between the surface and the neutral molecule compared to the dipole-dipole interactions that bond the complex to the surface below the pKₐ. Non-equilibrium effects on the adsorption reaction were minor. Adsorption-desorption was on the order of seconds to minutes. Kinetic effects became more important as temperature decreased.
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3

Honda, Ethan Philip. "Resonant dynamics within the nonlinear Klein-Gordon equation : Much ado about oscillons /." Full text (PDF) from UMI/Dissertation Abstracts International, 2000. http://wwwlib.umi.com/cr/utexas/fullcit?p9992817.

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4

Thapa, Mahendra B. "Molecular Dynamics Simulation of Calbindin D-9k in apo, Singly and Doubly Loaded States in Various Side-chains." University of Cincinnati / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1470044265.

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5

Jin, Yining. "Water dynamics at the MHCI-peptide binding interface studied by Hydrogen-deuterium exchange and structural studies of Apo A-I mimetic peptide-lipid binding." University of Toledo Health Science Campus / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=mco1404706445.

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6

Vargas, Eliane Teixeira. "Integração de mídias digitais no ensino de Geometria : um estudo com o oitavo ano do Ensino Fundamental." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2015. http://hdl.handle.net/10183/118897.

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Esta dissertação apresenta uma proposta de ensino de conceitos de Geometria integrando mídias digitais e recursos didáticos. O objetivo central do trabalho foi contribuir para o processo de aprendizagem de conceitos de geometria, utilizando recursos tecnológicos, tais como vídeos, fotografia digital e software de geometria dinâmica, com alunos do oitavo ano do Ensino Fundamental. Além disso, disponibilizar uma proposta de ensino na forma de website composta por uma sequência didática, envolvendo definições, resoluções de problemas, multimídia, glossário de termos e atividades a serem desenvolvidas com materiais manipulativos e com o software GeoGebra. O estudo foi desenvolvido no ano de 2013, com uma turma de alunos do oitavo ano de uma escola pública da Rede Municipal de Ensino da cidade de Esteio/RS. Para analisar a proposta e o avanço dos alunos, utilizou-se como referenciais teóricos Vergnaud (1993) e Gravina (1996, 2001) e o estudo de caso como metodologia. A partir da análise dessa prática, a autora percebeu que a geometria dinâmica, juntamente com a integração dos demais recursos didáticos, possibilitou que os alunos avançassem na compreensão dos conceitos geométricos abordados. Também, os alunos tiveram a oportunidade de compreender e aplicar diferentes propriedades destes conceitos a situações cotidianas. A cada tópico desenvolvido, conceitos e propriedades vistos em tópicos anteriores foram resgatados, oportunizando que os alunos ampliassem seus conhecimentos sobre determinados conceitos.
This dissertation presents an educational proposal of Geometry concepts integrating digital media and educational resources. The central objective was to contribute to the process of learning geometry concepts using technological resources, such as videos, digital photography and dynamic geometry software, with students of the eighth grade of elementary school. In addition, provide an educational proposal in the form of website consists of a didactic sequence, involving definitions, problem solving, multimedia, glossary of terms and activities to be undertaken with manipulative materials and GeoGebra software. The study was conducted in 2013, with a class of eighth graders from a public school in Municipal Schools in the city of Esteio / RS. To examine the proposal and the progress of students, it was used as theoretical references Vergnaud (1993) and Gravina (1996, 2001) and the case study as a methodology. From the analysis of this practice, the author realized that the dynamic geometry, along with the integration of other educational resources, enabled students to advance in understanding of geometric concepts addressed. Also, students had the opportunity to understand and apply different properties of these concepts to everyday situations. Each topic developed concepts and properties seen in previous topics have been rescued, providing opportunities for students to broaden their knowledge of certain concepts.
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7

Machado, Paulo Cordeiro. "Análise multiescala da abrasão de aços austeníticos ao manganês aplicados em britadores de minério." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/3/3151/tde-28112017-073503/.

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O desgaste abrasivo de dois aços austeníticos ao manganês, materiais com grande utilização na mineração, foi estudado empregando metodologia multiescala (escalas: macro, meso e micro). Na macroescala foram estudados os mecanismos de dano e de desgaste de revestimento de britador utilizado em campo. Na mesoescala foram realizados ensaios de britador de mandíbula e de esclerometria linear. Na microescala o ensaio de esclerometria linear foi utilizado para avaliar os efeitos da camada encruada em campo e da orientação cristalográfica dos grãos austeníticos dos aços com 12 %Mn e 20 %Mn. As técnicas de caracterização utilizadas nesta pesquisa foram: macro e microdureza, nanodureza instrumentada, MO, MEV, DRX, EBSD, FIB e MET. A pesquisa foi dividida em três Capítulos, intitulados: \"Desgaste abrasivo dos aços austeníticos com 12 %Mn e 20 %Mn via ensaio de britador de mandíbula\"; \"Efeito do encruamento e da orientação cristalográfica no desgaste por riscamento dos aços austeníticos 12 %Mn e 20 %Mn\"; e \"Microestrutura da subsuperfície do aço austenítico com 12 %Mn deformado por desgaste abrasivo\". O primeiro Capítulo mostrou, a partir do ensaio de britador de mandíbulas (mesoescala), que o aço com 20 %Mn tem tendência de maior resistência ao desgaste que o aço com 12 %Mn. Este resultado foi obtido para a mandíbula fixa do britador, na qual a severidade de desgaste foi superior a mandíbula móvel, por apresentar microcorte e microsulcamento como micromecanismos predominantes, enquanto na mandíbula móvel o micromecanismo predominante foi a microendentação. No segundo Capítulo observou-se que o desgaste por riscamento (mesoescala e microescala) não depende do perfil de encruamento gerado em campo. Entretanto, foi identificado o efeito da orientação cristalográfica, planos (001), (111) e (101), no desgaste por riscamento dos aços com 12 %Mn e 20 %Mn. No último Capítulo a análise multiescala mostrou que a microestrutura deformada na subsuperfície sofre alterações semelhantes em diferentes intensidades. Nas três escalas de análise foram observadas uma camada com grãos ultrafinos (nanométricos), na subsuperfície, e uma de transição com maclas de deformação. A formação dos grãos ultrafinos foi associada à recristalização dinâmica por deformação plástica, na qual faz parte do mecanismo de auto reparação superficial. Além dos resultados apresentados, o desenvolvimento desta pesquisa de doutorado permitiu a elaboração de duas metodologias: i. análise do efeito da orientação cristalográfica no desgaste por microesclerometria; e ii. análise de microestrutura revelada por ataque iônico - FIB.
The abrasive wear of two manganese austenitic steels, materials broadly used in mining industry, was studied using multiscale methodology (scales: macro, meso and micro). In the macroscale the mechanisms of damage and wear of in-service crusher liner were studied. In the mesoscale, jaw crusher and linear scratch tests were performed. In the microscale the linear scratch test was used to evaluate the effects of the hardening layer and the crystallographic orientation of the austenitic grains of steels with 12 %Mn and 20 %Mn. The characterization techniques used in this research were: macro and microhardness, instrumented nanohardness, OM, MEV, DRX, EBSD, FIB and TEM. The research was divided into three chapters, entitled: \"Abrasive wear of steels with 12 %Mn and 20 %Mn via jaw crusher test\"; \"The effect of the in-service workhardening and crystallographic orientation on the micro-scratch wear of austenitic steels with 12 %Mn and 20 %Mn\"; and \"Subsurface microstructure of the deformed austenitic steel with 12 %Mn by abrasive wear\". The first chapter showed, from the jaw crusher tests (i.e. mesoscale), that the steel with 20 %Mn tends to be more wear resistant than the steel with 12 %Mn. This result was obtained to the fixed jaw crusher, in which the wear severity was superior to the movable jaw, since it presents microcutting and microploughing as predominant micromechanisms, whereas in the mobile jaw the predominant micromechanism was microendentation. In the second chapter, it was observed that scratch wear (i.e. meso and microscale) does not depend on the in-service work-hardening profile. However, it was identified the effect of crystallographic orientation, (001), (111) and (101) planes, on the scratch wear of the steels with 12% Mn and 20% Mn. In the last chapter, the multiscale analysis showed that the subsurface deformed microstructure changes with different intensities. At the three analysis scales, a layer with ultrafine grains was observed in the subsurface and mechanical twins. The formation of this layer, with nanometric grains, was associated with dynamic recrystallization by plastic deformation, in which it is part of the self healing effect. In addition to the results found, the development of this doctoral research allowed for the elaboration of two methodologies: i. Analysis of the effect of crystallographic orientation on the scratch wear; and ii. Microstructure analysis revealed by ion etching - FIB.
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8

Orbolato, Leandro Marino Takazono. "Análise do comportamento sísmico das partes internas de um equipamento de proteção ambiental." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/3/3144/tde-16072013-172126/.

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Neste trabalho o comportamento sísmico das partes internas de um equipamento de proteção ambiental é estudado. O equipamento, um precipitador eletrostático, é composto basicamente de uma grande caixa de metal elevada, que contem eletrodos positivos e negativos responsáveis pela coleta de material particulado no fluxo de gases industriais. Esses componentes se comportam como pêndulos. No modelo foram considerados os deslocamentos sísmicos horizontais em duas direções ortogonais. De especial interesse está o fato de os eletrodos terem a liberdade de oscilar no plano de uma direção, mas não no seu plano perpendicular. Serão analisados quatro modelos com um, dois, três graus de liberdade, e um com três graus de liberdade linearizado. O modelo mais completo considera como graus de liberdade e coordenadas generalizadas os dois deslocamentos horizontais, e o deslocamento angular do pendulo. Foi adotada a formulação Lagrangeana para derivar as equações de movimento do modelo. As equações diferenciais do movimento de segunda ordem obtidas apresentam um comportamento não linear. Os movimentos sísmicos, que são estocásticos por natureza, serão simulados por meio de um registro sísmico existente, arbitrariamente escolhido. A obtenção dos parâmetros do modelo a ser estudado é de especial interesse para a melhor previsão do comportamento do equipamento quando solicitado a esforços sísmicos. A integração numérica do modelo matemático é efetuada, sendo posteriormente realizados comparativos entre as respostas dos modelos, quando submetidos tanto a vibração livre, como a um sismo real já registrado, arbitrário.
In this work, the seismic behavior of the internal parts of an environmental control equipment is studied. The equipment, an electrostatic precipitator, is basic composed of an elevated large steel box, containing positive and negative electrodes that capture powdered material of industrial effluent gases. These internal components behave essentially as pendula. In the mathematical model seismic motions in two orthogonal directions are considered. It is interesting to realize that the pendular electrodes are free to swing in one plane but not in the other plane. Four increasingly complex nonlinear models are analyzed, with one, two and three degrees of freedom, as well as one 3-degree-of-freedom linearized model. The generalized coordinates of the most complete model are the two horizontal displacements of the top mass and the angular motion of the pendulum. Lagranges formulation is used to derive the equations of motion of the models. These are second order nonlinear ordinary differential equations. The base seismic motions, that are stochastic in nature, are replaced by a arbitrarily chosen existing seismic record. The models parameters are carefully chosen to a good prediction of the equipment under seismic support excitation. Numerical integration of the mathematical model is performed, and comparisons are made of the several models response submitted to free vibrations and to an existing seismic record.
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9

Svensson, Erik R., and Klas Lagerqvist. "Evaluating pheromone intensities and 2-opt local search for the Ant System applied to the Dynamic Travelling Salesman Problem." Thesis, KTH, Skolan för datavetenskap och kommunikation (CSC), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-209404.

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Ant Colony Optimization (ACO) algorithms have been successful in solving a wide variety of NPhard optimization problems. The Traveling Salesman Problem (TSP) has served as a benchmarking problem for many novel ACO algorithms. The slightly harder Dynamic Traveling Salesman Problem (DTSP) is more realistic in the sense that real-time changes happen in the graph belonging to a TSP instance. This thesis studied the original ACO algorithm: the Ant System, and how the amount of pheromone deposited by the ants within the algorithm affected the performance when solving both TSP and DTSP problems. Additionally, 2-opt local search was added to the algorithm, to see how it impacted the performance. We found that when the ants deposited a greater amount of pheromone, the performance for TSP increased, while the performance for DTSP decreased. We concluded that the Ant System in its original form is unsuitable for solving the DTSP. 2-opt local search improved the performance in all instances.
Ant Colony Optimization-algoritmer (ACO) har visat sig vara bra på att lösa många olika NP-svåra optimeringsproblem. För att mäta prestandan för nya ACO-algoritmer har i många fall Handelsresandeproblemet (eng. TSP) använts. Den dynamiska varianten av TSP (eng. DTSP), är ett något svårare problem då förändringar i grafen kan ske i realtid. Denna uppsats utredde hur olika mängder feromon som avges av myrorna inuti algoritmen Ant System, påverkade prestandan för både TSPoch DTSP-instanser. Utöver detta studerades hur den lokala sökningsheuristiken 2-opt påverkade prestandan. Resultaten visade att om myrorna tilläts släppa mer feromoner, ökade prestantan för TSP, men minskade för DTSP. Därav drog vi slutsatsen att algoritmen Ant System i sin ursprungliga form ej är lämplig för att lösa DTSP. Den lokala söknigsheuristiken 2-opt förbättrade prestandan i alla tester.
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10

Castro, Rafael Alves de. "Modelagem Computacional de Ligações Semi-Rígidas e sua Influência na Resposta Dinâmica Não-Linear de Pórticos de Aço." Universidade do Estado do Rio de Janeiro, 2006. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=426.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
A comunidade científica tem conhecimento de que uma das etapas mais relevantes no projeto de estruturas de aço e mistas, diz respeito a uma avaliação precisa sobre os modelos estruturais que representam o comportamento real das ligações viga-coluna. Este assunto tem sido objeto de vários trabalhos de pesquisa nas ultimas décadas. Na prática corrente do projeto de estruturas de aço, a grande maioria das ligações viga-coluna é representada por modelos flexíveis (rótulas) ou rígidos (engastes). Contudo, na maior parte dos casos práticos, essas ligações assumem um comportamento intermediário, ou seja, semi-rígido. Um outro ponto importante acerca do assunto diz respeito à avaliação da resposta dinâmica de estruturas de aço com a consideração pertinente do efeito das ligações, especialmente, no que tange as semi-rígidas, já que a maioria dos trabalhos de pesquisa concentra-se apenas no estudo da resposta estática dos modelos. Assim sendo, esta investigação apresenta uma contribuição inicial no que tange ao emprego de elementos que representem mais fielmente os efeitos das ligações estruturais na análise dinâmica de estruturas de aço, evidentemente, com a consideração do efeito de semi-rigidez dessas ligações. Desta forma, este trabalho de pesquisa propõe o uso de um modelo mecânico com elementos de mola rotacionais não-lineares, objetivando simular adequadamente o efeito das ligações viga-coluna especificamente em pórticos de aço. Inicialmente, foi feita uma calibração do modelo computacional desenvolvido, comparando os resultados obtidos mediante o uso do modelo de mola rotacional com os dados obtidos na literatura técnica sobre o assunto. Na seqüência, desenvolve-se uma analise paramétrica extensa, com a inclusão de todos os efeitos mencionados no parágrafo anterior, de forma a avaliar mais detalhadamente a resposta dinâmica dos pórticos de aço, deslocamentos e esforços, com base no estudo de um edifício residencial de quatro pavimentos.
The scientific community has realized that one of the most relevant stages in the design of steel and composite structures concerns to an accurate evaluation about the structural models that represent the actual behaviour of the beam-to-column connections. This issue has been the subject of many studies over the last decade. In the current design of steel structures, most of the beam-to-column connections are represented by pinned or rigid models. However, in most of the current cases, the connections have an intermediate behaviour between these two cases. Another important issue about the correct evaluation of the dynamic response of steel structures its about the consideration of the effects of the joints, especially of the semi-rigid joints, since most of the studies consider only a static analysis of the models. Therefore, this dissertation has proposed the use of a mechanical model of rotational springs with a nonlinear behaviour, objectifying a proper simulation of the beam-to-column effects in steel frames. The numeric results were obtained along the present study, and calibrated based on many computer models available on the literature. On the sequence, a large parametric analysis is developed, including all the effects mentioned before, objectifying evaluate more precisely the dynamic response of the steel frames (displacements and forces), based on the static and dynamic response of a four storey edifice.
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Nogueira, Fabiano da Cruz. "Influência do raio de ponta do entalhe, do tipo de carregamento e da microestrutura no processo à fratura do aço estrutural ABNT-4340 /." Ilha Solteira : [s.n.], 2006. http://hdl.handle.net/11449/94491.

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Orientador: Ruis Camargo Tokimatsu
Banca: Wyser Jose Yamakami
Banca: André Luis Moreira de Carvalho
Resumo: O ensaio de impacto Charpy convencional é um ensaio mecânico consagrado no meio científico e industrial. Sua função é determinar a energia total absorvida para causar a fratura completa de um corpo-de-prova entalhado, padronizado segundo a norma ASTM E?23. Entretanto, a energia global absorvida possui um valor de uso muito limitado. Ela normalmente não é aceita como um indicador quantitativo da resistência à fratura do material. Assim, através da instrumentação adequada, pode-se aumentar a quantidade de informações obtidas a partir do ensaio de impacto Charpy clássico. No presente trabalho, estudou-se a influência do raio de ponta do entalhe, do tipo de carregamento e da microestrutura dos corpos-de-prova no processo à fratura dinâmica do aço ABNT-4340 a partir do ensaio Charpy Instrumentado. As diferentes condições microestruturais foram resultantes de diferentes condições de tratamentos térmicos: como-recebido, como-temperado e revenido nas seguintes temperaturas: 473K, 573K, 673K e 773K. Para cada microestrutura foram confeccionados corpos-de-prova com dois tipos de raio de ponta - pré-trincado e entalhe arredondado (0,25mm). Os corpos-de-prova assim preparados foram submetidos ao ensaio Charpy Instrumentado e tiveram seus sinais digitalizados. O sinal capturado com tal cadeia de medição foi utilizado na determinação dos valores de tenacidade à fratura dinâmica. Os resultados experimentais foram obtidos através dos ensaios de dureza, monotônicos (em três pontos), dinâmicos (Ensaio de Impacto Charpy). Os ensaios de dureza foram realizados com objetivo de ratificar a qualidade dos tratamentos térmicos. Os ensaios monotônicos servirão como referências para auxiliar o entendimento dos dados obtidos com os ensaios dinâmicos.
Abstract: The proof of conventional impact Charpy is a mechanic proof consecrated in scientific in industry. Its function is determinate the absorb total energy in order to the complete fracture in a indented proof body, standardized according to the ASTM E- 23 pattern. Therefore, the absorb global energy has a very limited value. It is not accepted a quantities indicator of resistance to the matter fracture. Thus, though adequate instrumentation, it can increase the quantity of information obtained from the proof of the classic impact Charpy. In this paper, we intend to study the influence of the ray of intende tip, of the loading type and of the microstructure of proof bodies in process the fracture of the structural steel ABNT-4340 from the instrumented proof Charpy. The different microstructure conditions are resulted of different conditions of thermal treatments: drawgeting, draw tempering, drawing in following temperatures: 473 K, 573 K, 673 K and 773 K. For each microstructures prepared proof body with two types of tip ray - sharp rack and rounding indented (0,25 mm). Proof bodies prepared this way are submitted the instrumented proof Charpy and have your signal digitalized. The signal capturing with such ranger of measurement will de used in determination of values of toughness to dynamic fracture. The experimental result were obtained through the rehearsals of hardness, almost-static (in three points), dynamic (instrumented proof Charpy). The rehearsals of hardness were accomplished with objective of ratifying the quality of the thermal treatments. The rehearsals almost-static will serve as references for to aid the understanding of the data obtained with the dynamic rehearsals.
Mestre
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12

Dubois, Jonathan. "Electron dynamics for atoms driven by intense and elliptically polarized laser pulses." Thesis, Aix-Marseille, 2019. http://www.theses.fr/2019AIXM0297.

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Assujettir des atomes ou des molécules à des impulsions lasers de fortes intensités done lieu à une variété de phénomènes hautement non-linéaires, tels que par exemple l'ionisation des électrons et la radiation de photons de hautes fréquences. Les distributions des vitesses des électrons ionisés ou des fréquences des photons radiés encodent des informations pertinentes sur les atomes ou les molécules ciblés à l'échelle temporelle naturelle des électrons, l'attoseconde-qui est un millionième, d'un millionième, d'un millionième d'une seconde. Comprendre la dynamique des électrons ionisés ainsi qu'identifier les mécanismes de radiation de hautes fréquences sont des étapes essentielles afin d'interpréter et décoder les informations cryptées dans les mesures expérimentales.Dans cette thèse, des atomes soumis à des impulsions lasers de fortes intensités polarisées elliptiquement dans le régime infra-rouge sont étudiés théoriquement. Malgré leur nature fondamentalement quantique dans les atomes, les électrons manifestent certains comportements classiques lorsqu'ils sont sujets à des impulsions lasers de fortes intensités. Nous exploitons ces traits classiques pour comprendre et illustrer, à l'aide des trajectoires, les mécanismes physiques en jeu afin d'interpréter les résultats expérimentaux. Après ioniser, le mouvement des électrons est analysé en utilisant des techniques issues de la dynamique non-linéaire. Ce travail de thèse démontre la complémentarité de la mécanique quantique et de la dynamique non-linéaire pour comprendre et illustrer des mécanismes impliqués lorsque des atomes sont sujets à des impulsions lasers de fortes intensités polarisées elliptiquement
Subjecting atoms or molecules to intense laser pulses gives rise to a variety of highly nonlinear phenomena, such as for instance the ionization of electrons and the radiation of high-frequency photons. The distributions of the velocity of the ionized electrons of the frequency of the radiated photons measured at the detector encode relevant informations on the target atoms and molecules at the natural time scale of the electrons, the attosecond-that is, million, million, millionths of a second. Understanding the dynamics of the ionized electrons and identifying the mechanisms of high-frequency radiation are essential steps toward interpreting and decoding the informations encrypted in the experimental measurements.In this thesis, atoms subjected to intense and elliptically polarized laser fields in the infrared regime are theoretically studied. Despite their fundamental quantal nature in atoms, electrons display some classical behaviors when subjected to intense laser pulses. We exploit these classical features to understand and picture, with the help of trajectories, the physical mechanisms at play in order to interpret experimental measurements. After ionizing, the motion of the electrons is analyzed using techniques from nonlinear dynamics. This thesis work demonstrates the complementarity of quantum mechanics and nonlinear dynamics for understanding and illustrating the mechanisms involved when atoms are subjected to intense and elliptically polarized laser pulses
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13

Häckel, Sascha. "Hybride Ansätze basierend auf Dynamic Programming und Ant Colony Optimization zur mehrkriteriellen Optimierung Kürzester-Wege-Probleme in gerichteten Graphen am Beispiel von Angebotsnetzen im Extended Value Chain Management." Master's thesis, Universitätsbibliothek Chemnitz, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-61086.

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In einer von Vernetzung und Globalisierung geprägten Umwelt wächst der Wettbewerbsdruck auf die Unternehmen am Markt stetig. Die effektive Nutzung der Ressourcen einerseits und die enge Zusammenarbeit mit Lieferanten und Kunden andererseits führen für nicht wenige Unternehmen des industriellen Sektors zu entscheidenden Wettbewerbsvorteilen, die das Fortbestehen jener Unternehmen am Markt sichern. Viele Unternehmen verstehen sich aus diesem Grund als Bestandteil so genannter Supply Chains. Die unternehmensübergreifende Steuerung und Optimierung des Wertschöpfungsprozesses stellt ein charakteristisches Problem des Supply Chain Managements dar und besitzt zur Erzielung von Wettbewerbsvorteilen hohes Potential. Produktionsnetzwerke sind ein wesentlicher Forschungsschwerpunkt der Professur für Produktionswirtschaft und Industriebetriebslehre an der TU Chemnitz. Das Extended Value Chain Management (EVCM) stellt ein kompetenzorientiertes Konzept für die Bildung und zum Betrieb hierarchieloser temporärer regionaler Produktionsnetzwerke im Sinne virtueller Unternehmen dar. Gegenstand dieser Arbeit ist ein diskretes Optimierungsproblem, dass einen mehrstufigen Entscheidungsprozesses unter Berücksichtigung mehrerer Ziele abbildet, der sich bei der Auswahl möglicher Partner in einem Produktionsnetzwerk nach dem Betreiberkonzept des EVCM ergibt. Da mehrere Zielstellungen bestehen, werden grundlegende Methoden der mehrkriteriellen Optimierung und Entscheidung erörtert. Neben der Vorstellung des Problems sollen mehrzielorientierte Ansätze im Sinne einer Pareto-Optimierung auf Basis des Dynamic Programmings als Verfahren zur Bestimmung von Optimallösungen sowie Ant Colony Optimization zur näherungsweisen Lösung vorgestellt werden. Darauf aufbauend werden verschiedene Möglichkeiten der Hybridisierung beider Methoden diskutiert. Die entwickelten Ansätze werden auf ihre Eignung im Rahmen der informationstechnischen Umsetzung des EVCM-Konzepts untersucht und einer Evaluierung unterzogen. Hierzu werden verschiedene Kennzahlen zur Beurteilung der Verfahren entwickelt. Die modellierten Algorithmen und entwickelten Konzepte beschränken sich nicht ausschließlich auf das betrachtete Problem, sondern können leicht auf Probleme mit ähnlichen Eigenschaften übertragen werden. Insbesondere das NP-vollständige mehrkriterielle Kürzeste-Wege-Problem stellt einen Spezialfall des behandelten Optimierungsproblems dar.
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14

Nogueira, Fabiano da Cruz [UNESP]. "Influência do raio de ponta do entalhe, do tipo de carregamento e da microestrutura no processo à fratura do aço estrutural ABNT-4340." Universidade Estadual Paulista (UNESP), 2006. http://hdl.handle.net/11449/94491.

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O ensaio de impacto Charpy convencional é um ensaio mecânico consagrado no meio científico e industrial. Sua função é determinar a energia total absorvida para causar a fratura completa de um corpo-de-prova entalhado, padronizado segundo a norma ASTM E?23. Entretanto, a energia global absorvida possui um valor de uso muito limitado. Ela normalmente não é aceita como um indicador quantitativo da resistência à fratura do material. Assim, através da instrumentação adequada, pode-se aumentar a quantidade de informações obtidas a partir do ensaio de impacto Charpy clássico. No presente trabalho, estudou-se a influência do raio de ponta do entalhe, do tipo de carregamento e da microestrutura dos corpos-de-prova no processo à fratura dinâmica do aço ABNT-4340 a partir do ensaio Charpy Instrumentado. As diferentes condições microestruturais foram resultantes de diferentes condições de tratamentos térmicos: como-recebido, como-temperado e revenido nas seguintes temperaturas: 473K, 573K, 673K e 773K. Para cada microestrutura foram confeccionados corpos-de-prova com dois tipos de raio de ponta - pré-trincado e entalhe arredondado (0,25mm). Os corpos-de-prova assim preparados foram submetidos ao ensaio Charpy Instrumentado e tiveram seus sinais digitalizados. O sinal capturado com tal cadeia de medição foi utilizado na determinação dos valores de tenacidade à fratura dinâmica. Os resultados experimentais foram obtidos através dos ensaios de dureza, monotônicos (em três pontos), dinâmicos (Ensaio de Impacto Charpy). Os ensaios de dureza foram realizados com objetivo de ratificar a qualidade dos tratamentos térmicos. Os ensaios monotônicos servirão como referências para auxiliar o entendimento dos dados obtidos com os ensaios dinâmicos.
The proof of conventional impact Charpy is a mechanic proof consecrated in scientific in industry. Its function is determinate the absorb total energy in order to the complete fracture in a indented proof body, standardized according to the ASTM E- 23 pattern. Therefore, the absorb global energy has a very limited value. It is not accepted a quantities indicator of resistance to the matter fracture. Thus, though adequate instrumentation, it can increase the quantity of information obtained from the proof of the classic impact Charpy. In this paper, we intend to study the influence of the ray of intende tip, of the loading type and of the microstructure of proof bodies in process the fracture of the structural steel ABNT-4340 from the instrumented proof Charpy. The different microstructure conditions are resulted of different conditions of thermal treatments: drawgeting, draw tempering, drawing in following temperatures: 473 K, 573 K, 673 K and 773 K. For each microstructures prepared proof body with two types of tip ray - sharp rack and rounding indented (0,25 mm). Proof bodies prepared this way are submitted the instrumented proof Charpy and have your signal digitalized. The signal capturing with such ranger of measurement will de used in determination of values of toughness to dynamic fracture. The experimental result were obtained through the rehearsals of hardness, almost-static (in three points), dynamic (instrumented proof Charpy). The rehearsals of hardness were accomplished with objective of ratifying the quality of the thermal treatments. The rehearsals almost-static will serve as references for to aid the understanding of the data obtained with the dynamic rehearsals.
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15

Santos, Bill Paiva dos. "Avaliação da degradação da tenacidade frente a uma falha dinâmica no aço API 5L X70." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2017. http://hdl.handle.net/10183/158268.

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Os ensaios mecânicos são mundialmente empregados para caracterização e implementação de diversos materiais. Dentre a vasta gama de ensaios existentes, o ensaio de impacto convencional é consagrado no meio científico, industrial e na indústria do óleo e gás onde a sua função básica é determinar a energia total absorvida na fratura de um corpo-de-prova entalhado conforme as recomendações da norma ASTM E23. Entretanto, a energia global absorvida possui um valor de uso muito limitado e ela normalmente não é aceita como um indicador quantitativo da resistência à fratura do material. Assim, com a utilização de uma máquina de ensaios de impacto instrumentada, torna-se possível a aquisição de um maior número de informações obtidas através de um ensaio de impacto clássico, como por exemplo, o estudo detalhado da integridade estrutural de materiais utilizados na fabricação de dutos. Desta maneira, o presente trabalho tem como objetivo avaliar a tenacidade de um duto de aço API 5L X70 sem costura, com 11 polegadas de diâmetro externo e ½ polegada de parede, frente a uma falha dinâmica, através da tenacidade a fratura, comparando carregamento estático com dinâmico através dos resultados de J0,2 e Jm. Entretanto a tenacidade a fratura é consideravelmente afetada para altas taxas de deformação, com redução de aproximadamente 30% nas amostras com orientação de entalhe X-Y (defeito lateral passante) e de aproximadamente 40% nas amostras com orientação de entalhe X-Z (defeito superficial), demostrados através do JΔinit.
Mechanical testing are worldwide employed for materials characterization and implementation. Among the large group of the existing tests, the conventional impact test has been used for industry and academic fields, especially oil and gas engineering in order to evaluate the energy absorbed of a notched sample, according to the ASTM E23 standard. However, the energy absorbed has a limited use and is not usually accepted as a quantitative indicator of the fracture thougness. Thus, by using an instrumented impact test, there will be an increasing in the amount of information obtained than the traditional impact test and, thefore, a detailed study of the structural integrity of materials can be carried out for manufacturing of pipes. Hence, this study aims to characterize a pipe steel API 5L X70 seamless, with 11 inches outside diameter and ½ inche of wall, against dynamic failure through fracture toughness, comparing static loading with dynamic through the results of J0,2 and Jm. However, fracture toughness is considerably affected at high deformation rates, with a reduction of approximately 30% in X-Y notch (through thickness defect) and approximately 40% in X-Z notch (surface defect) samples, demonstrated for JΔinit.
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16

Lara, Heterson Luiz de. "UMA PROPOSTA DE UTILIZAÇÃO DE MÍDIAS SOCIAIS NO ENSINO DE FÍSICA PARA AS TURMAS DE 1° ANO DO ENSINO MÉDIO, COM ÊNFASE À DINÂMICA DE NEWTON." UNIVERSIDADE ESTADUAL DE PONTA GROSSA, 2016. http://tede2.uepg.br/jspui/handle/prefix/2138.

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This work presents an alternative to the teaching of Physics for the first year of high school, with emphasis on the Dynamic teaching and using as a pedagogycal tool social networking WhatsApp. Was applied in a public school with classes in the series proposal, presents all development activities, theoretical and methodological discussion and mainly the results obtained, shows that it is possible to break away from the traditional teaching of kinematics and with excessive mathematical formalism traditional without, however, abandoning what is also important in this form of education and of the mathematical formalism necessary. The use of WhatsApp as a pedagogycal tool is an alternative proposal that caters to the emergence of new forms of communication, something that is quite present in school environments, but are not always used. The results of the application of the work show that in this sense can mitigate also the conflict generated by the excessive use of smartphones in the classroom and have a form of communication and Physical content sharing within and outside of the classroom. Also, features a class based on the proposal and intends to be an element of pedagogical support to physics teaching in classes from first year of high school.
Este trabalho apresenta uma alternativa para o ensino da disciplina de Física para o primeiro ano do Ensino Médio, com ênfase ao ensino da Dinâmica e utilizando como ferramenta pedagógica a rede social WhatsApp. Foi aplicado em uma escola pública com turmas da série proposta, apresenta todo o desenvolvimento das atividades, a discussão teórica e metodológica e, principalmente os resultados obtidos, mostra que é possível romper com o ensino tradicional de Cinemática e com o formalismo matemático tradicional sem, contudo, abandonar o que é também importante nesta forma de ensino e do formalismo matemático necessário. A utilização do WhatsApp como ferramenta pedagógica é uma proposta alternativa que atende ao surgimento das novas formas de comunicação, algo que está bastante presente nos ambientes escolares, porém nem sempre são aproveitadas. Os resultados da aplicação do trabalho mostram que neste sentido pode-se amenizar também o conflito gerado pela utilização excessiva de smartphones em sala de aula e, ainda, ter uma forma de comunicação e compartilhamento de conteúdo de Física dentro e fora de sala de aula. Também apresenta um roteiro de aulas com base na proposta e se propõe a ser um elemento de apoio pedagógico ao ensino de Física em turmas de primeiro ano do Ensino Médio.
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17

SANTOS, Ives José Adriano dos. "Análise dinâmica de suportes para antenas em torres metálicas para telecomunicações." Universidade Federal de Pernambuco, 2015. https://repositorio.ufpe.br/handle/123456789/18079.

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Na última década, o crescimento da telefonia celular no Brasil venceu os limites das grandes capitais, levando a rede a cobrir municípios antes desprovidos de tal tecnologia. A transmissão do sinal pode ocorrer de diversas formas, mas, de fato, a mais comumente utilizada é por meio de antenas sustentadas por torres metálicas. Na prática, as antenas são instaladas em qualquer momento após a montagem da torre, mesmo anos após sua construção, sem qualquer verificação estrutural e, por vezes, excedendo a capacidade de carga nominal. Além disso, na maioria dos casos, não são levados em conta certos cuidados com relação ao posicionamento de suportes e das próprias antenas. Portanto, é comum encontrarmos antenas instaladas de forma inadequada, sendo colocadas fora da silhueta da torre. Este posicionamento, aliado com a ação dinâmica ocasionada pelo vento, pode trazer problemas graves à estrutura. Neste trabalho, são apresentados dois casos reais de torres metálicas que sofreram danos estruturais devido ao problema em questão. Este trabalho tem como principal objetivo apresentar uma solução de amortecimento para as vibrações causadas pelo vento em antenas para telecomunicações. A proposta visa utilizar elastômeros, como o Neoprene, entre a cantoneira do montante e as abraçadeiras dos suportes, reduzindo assim o período de vibração e, consequentemente, os efeitos da fadiga.
In the last decade, the growth of mobile telephony in Brazil won the boundaries of the great capitals, leading the network to cover cities before devoid of such technology. The signal transmission can occur in various ways, but, in fact, the most commonly used is through antennas supported by steel towers. In practice, the antennas are installed at any time after assembly of the tower, even years after its construction, without any structural verification and sometimes exceeding the rated load capacity. Moreover, in most cases, care is not taken into account in relation to the positioning brackets and their antennas. Therefore, it is common to find antennas installed improperly, being placed outside the tower silhouette. This positioning, combined with dynamic action brought by the wind, can bring serious problems to the structure. In this work, we present two real cases of metal towers that have suffered structural damage due to the problem at hand. The objective of this work is to present a solution for damping the vibrations caused by the wind in telecommunications antennas. The proposal to use elastomers, such as neoprene, between the bracket and the tower column, thus reducing the vibration period and, consequently, the effects of fatigue.
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18

Fang, Jianxin. "Analyse et algorithmes de résolution de systèmes ATO (Assemble-To-Order) : Applications aux systèmes du type W." Thesis, Ecole centrale de Lille, 2017. http://www.theses.fr/2017ECLI0012/document.

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Nous analysons un type W de système de l’Assemble-à-commande avec des délais de livraison aléatoires, l'arrivée aléatoire de la demande et des ventes perdues, en temps continu. Nous formulons le problème en tant que processus de décision Markov à l'horizon infini. Nous nous éloignons de l'approche standard en caractérisant une région de l'espace d'état où toutes les propriétés de la fonction de coût tiennent. Nous caractérisons la politique optimale dans cette région. En particulier, nous montrons que, dans l'intérieur de la région récurrente, les composants sont toujours produits. Nous caractérisons également la politique d'allocation de composants optimale qui spécifie si une demande de produit arrivant devrait être remplie. Notre analyse révèle que la politique d'allocation optimale est contre-intuitive. Par exemple, même lorsqu'un produit domine l'autre, en termes de coût/taux de vente perdue, sa demande peut ne pas avoir une priorité absolue par rapport à la demande de l'autre produit. Une telle caractéristique n'a pas été observée dans de nombreux paramètres intégrés de production/inventaire où l'allocation d'inventaire suit une priorité fixe pour satisfaire les exigences. Nous montrons également que la structure de la politique optimale reste la même pour les systèmes à production par lots, les temps de production répartis par Erlang et la demande de produits non unitaire. Enfin, nous proposons des heuristiques efficaces qui peuvent être utilisées comme substitut à la politique optimale ou peuvent être utilisées comme une politique de départ pour les algorithmes communs utilisés pour obtenir une politique optimale dans le but de réduire leur temps de calcul
We analyze a W-configuration assemble-to-order system with random lead times, random arrival of demand, and lost sales, in continuous time. We formulate the problem as an infinite-horizon Markov decision process. We deviate from the standard approach by first characterizing a region (the recurrent region) of the state space where all properties of the cost function hold. We then characterize the optimal policy within this region. In particular, we show that within the interior of the recurrent region components are always produced. We also characterize the optimal component allocation policy which specifies whether an arriving product demand should be fulfilled. Our analysis reveals that the optimal allocation policy is counter-intuitive. For instance, even when one product dominates the other, in terms of lost sale cost and lost sale cost rate (i.e., demand rate times the lost sale cost), its demand may not have absolute priority over the other product’s demand. Such a feature has not been observed in many integrated production/inventory settings where inventory allocation follows a fixed priority in satisfying demands. We also show that the structure of the optimal policy remains the same for systems with batch production, Erlang distributed production times, and non-unitary product demand. Finally, we propose efficient heuristics that can be either used as a substitute for the optimal policy or can be used as a starting policy for the common algorithms that are used to obtain the optimal policy in an effort to reduce their computational time
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19

Figueiredo, Fábio Pereira. "Estudo do comportamento dinâmico de passarelas devido ao caminhar de pedestres." Universidade do Estado do Rio de Janeiro, 2005. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=420.

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Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro
Atualmente têm sido projetadas passarelas cada vez mais esbeltas devido aoavanço da tecnologia e das pesquisas científicas na área de desenvolvimento de novos materiais. Uma conseqüência direta disso é o aumento considerável de problemas de vibração. No caso particular de passarelas, este fenômeno ocorre quando a freqüência fundamental da estrutura é igual ou se aproxima da freqüência do passo do pedestre. Atividades como caminhar, correr ou pular produzem excitações dinâmicas. Essas forças dinâmicas, em determinados casos, podem vir a produzir níveis de vibração elevados e, por conseguinte, perturbar ou até mesmo alarmar as pessoas que estiverem utilizando a estrutura. Como o propósito primário das passarelas é o transporte de pedestres, as mesmas precisam estar seguras e apresentar um comportamento que não ofereça desconforto aos usuários. Assim sendo, o presente estudo foi desenvolvido de forma a dar uma contribuição no que tange a avaliação da resposta dinâmica de passarelas de pedestre, principalmente, no que se refere ao conforto humano. Para tal, são desenvolvidos diversos modelos de carregamento de forma a representar a travessia de pedestres sobre a estrutura. A análise em questão considera, inclusive, um modelo mais realista de carregamento desenvolvido para incorporar o impacto transiente do calcanhar devido ao caminhar humano. Neste modelo de carregamento, o movimento de pernas que causa a subida e descida da massa efetiva do corpo em cada passo foi considerado e a posição do carregamento dinâmico foi alterada de acordo com a posição do individuo, assim a função de tempo, correspondente a excitação induzida pela caminhada, teve uma variação espacial e temporal. A análise de diversos projetos distintos de passarelas foi realizada em um extenso estudo de casos, onde foram investigadas as respostas dinâmicas dessas estruturas. Em uma fase subseqüente, características estruturais e dinâmicas foram avaliadas através de um estudo paramétrico. Os resultados obtidos, em termos das acelerações verticais de pico e rms (root mean square), foram comparados com critérios de projeto. Através dos resultados analíticos e numéricos alcançados foi possível demonstrar a importância da modelagem do carregamento gerado durante uma caminhada e como esses resultados são fundamentais para uma boa avaliação da resposta dinâmica das estruturas. Os resultados obtidos ao longo do estudo indicam, claramente, que os projetistas estruturais devem ser alertados para distorções importantes que ocorrem quando as normas de projeto são utilizadas sem o devido cuidado. Um outro aspecto importante diz respeito ao fato de que em diversas passarelas analisadas observa-se que os critérios de conforto humano não são satisfeitos, demonstrando a importância da consideração dos efeitos dinâmicos provenientes dos seres humanos na análise desse tipo de problema.
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20

Langer, Natália Antunes dos Santos. "Estudo do conforto humano em pisos mistos (aço-concreto) submetidos a ações humanas rítmicas." Universidade do Estado do Rio de Janeiro, 2009. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=5635.

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Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro
Este trabalho de pesquisa objetiva o estudo do comportamento dinâmico de pisos mistos (aço-concreto), em edificações de andares múltiplos, sob o ponto de vista de conforto humano, quando essas estruturas encontram-se submetidas às atividades rítmicas provenientes dos seres humanos. A definição das ações dinâmicas atuantes sobre os modelos estruturais foi feita com base em resultados experimentais, com os indivíduos praticando atividades rítmicas e não rítmicas associadas à ginástica aeróbica e saltos à vontade. Os modelos estruturais investigados baseiam-se em edificações mistas de andares múltiplos. O sistema estrutural é do tipo misto (aço-concreto), composto por vigas de aço em seção do tipo I e laje de concreto armado. A análise fundamenta-se na modelagem computacional dos sistemas estruturais, através do Método dos Elementos Finitos (MEF). São empregadas técnicas usuais de discretização, por meio do emprego do programa ANSYS. Uma análise paramétrica foi desenvolvida sobre três modelos estruturais, com dois, três e quatro pavimentos. Os valores das acelerações máximas encontradas na análise são confrontados e comparados com os limites propostos por recomendações internacionais. Os resultados obtidos mostram que os limites recomendados em diversas normas de projeto foram ultrapassados. Esses resultados demonstram que atividades rítmicas oriundas dos seres humanos podem gerar acelerações de pico elevadas, violando critérios de projeto, no que concerne ao conforto humano. Foi observado também que estas ações dinâmicas podem comprometer o conforto humano em pisos adjacentes, próximos do local onde a carga dinâmica está sendo efetivamente aplicada.
The present dissertation investigates the dynamic behaviour of composite floors (steel-concrete) in multi-storey buildings when subjected to the human rhythmic activities, considering human comfort aspects. The dynamic loads were obtained through experimental tests with individuals carrying out rhythmic and non-rhythmic activities such as stimulated and non-stimulated jumping and aerobics. The investigated structural model was based on several building composite floors. The structural systems are composed of a composite (steel/concrete) solution made of an I steel profile and a reinforced concrete slab. The proposed analysis methodology adopted the usual mesh refinement techniques present in the finite element method simulations implemented in the ANSYS program. A parametric analysis was developed, using three different building composite floors with two, three and four storeys. The parametric study considered correlations between analytical and numerical results found in the technical literature. The results, in terms of maximum accelerations (peak accelerations) were compared with the limits proposed by design recommendations. The results indicated that the limits suggested by design recommendations are not satisfied. Such fact shows that these rhythmic activities may generate peak accelerations that violates design criteria when the human comfort is considered. It was verified that these dynamic loads generate considerable perturbations on adjacent areas. The influence caused by dynamic actions in adjacent floors near to the place where the load was applied also can compromise the human comfort.
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21

Cavalcanti, Paulo de Sá Pereira. "Investigação experimental da fadiga ao cisalhamento em lajes de pontes com pré-lajes." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/3/3144/tde-28022011-170148/.

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Um número significativo de pontes têm sido construídas na forma de grelhas de vigas pré-moldadas, sobre as quais apoiam-se pré-lajes com posterior concretagem de capa, finalizando a execução das lajes das mesmas. Esse processo construtivo tem sido largamente utilizado tendo em vista a racionalização da construção dispensando o uso de cimbramentos, abreviando consideravelmente os prazos de construção e consequentemente reduzindo os custos. Todavia no desenvolvimento do projeto, sabe-se que essas lajes são elementos altamente suscetíveis à fadiga e, tendo-se em vista a existência de concretagem em duas etapas (pré-laje e capa final) e concretos de idades diferentes, geram-se dúvidas obre o comportamento desta interface com relação às cargas dinâmicas atuantes no decorrer da vida útil da obra. A escassez de estudos ou pesquisas relacionadas a essa questão, levaram à realização do presente trabalho, de cunho experimental, e com o objetivo de se estudar o comportamento desses elementos submetidos às cargas de fadiga e as suas resistências finais no que se refere às cargas de ruptura antes e depois de fatigadas. Foram ensaiadas 9 lajes de concreto sendo 6 lajes com rugosidade normal (saliência dos agregados brita 1) e 3 com baixa rugosidade (alisamento com espátula de madeira). Não foram identificadas rupturas por fadiga e a resistência das lajes fatigadas se mantiveram, quando levadas a ruptura no final dos ensaios, no mesmo nível daquelas não fatigadas.
A significant number of bridges have been built in the form of grids of pre-cast beams on which pre-slab are supported, with posterior concreting of concrete cover, completing the execution of the slabs. This construction process has been widely used in order to rationalize the construction without shoring, shortening considerably the time of construction and thereby reducing costs. However in developing the project, it is known that these slabs are elements highly susceptible to fatigue and, keeping in mind the existence of concrete in two stages (pre-slab and final cover) and different ages, doubts about the behavior of this interface with respect to dynamic loads acting over the lifetime are generated. The scarcity of studies and researches related to this issue led to the realization of this experimental work, in order to study the behavior of these elements subjected to fatigue loading and their final resistance in relation to the failure load before and after fatigue loading. Tests were made in 9 concrete slabs, 6 with usual surface roughness (salience of crushed aggregates 1) and 3 with low roughness (smoothing with wooden spatula). It was verified that no rupture due to fatigue loading were identified and the resistance of the slabs submitted to fatigue loading remained on the same level of those not fatigued, when carried to cracking at the end of the tests.
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22

Zúñga, José Eduardo Villarroel. "Análise da resposta dinâmica experimental de uma passarela tubular mista, aço-concreto, submetida ao caminhar humano." Universidade do Estado do Rio de Janeiro, 2011. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=5531.

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Este trabalho de pesquisa apresenta como objetivo principal o desenvolvimento de investigação experimental dinâmica sobre estrutura real de uma passarela tubular mista aço-concreto. O sistema estrutural objeto deste trabalho corresponde a uma passarela composta por três vãos (32,5m, 17,5m e 20,0m, respectivamente) e dois balanços (7,50m e 5,0m, respectivamente), com comprimento total de 82,5m. A passarela com estrutura contínua de aço com as ligações soldadas se apoia em quatro pórticos também de aço. Estruturalmente está constituída por duas treliças planas que se interligam através de contraventamentos horizontais fixados na corda superior e inferior da treliça e lajes de concreto, formando um sistema misto com interação completa. A estrutura está submetida correntemente à travessia de pedestres e ciclistas. Testes experimentais foram realizados sobre o sistema estrutural e confrontados com resultados numéricos. Para a modelagem numérica do sistema são empregadas técnicas usuais de discretização, via método dos elementos finitos (MEF), por meio do programa ANSYS. Os resultados experimentais são analisados de acordo com a metodologia desenvolvida, sendo realizada análise modal experimental para a determinação das propriedades dinâmicas: freqüências, modos e taxa de amortecimento, enquanto que os resultados da estrutura, em termos de aceleração de pico, são comparados com os valores limites propostos por diversos autores, normas e recomendações de projeto, para uma avaliação do desempenho da estrutura em relação a vibração quando solicitada pelo caminhar dos pedestres no que diz respeito a critério para conforto humano.
This research has as main objective the development of a dynamical experimental investigation of a real structure a tubular composite steel-concrete footbridge. The structural system of this study corresponds to a footbridge composed by three spans (32,5m, 17,5m and 20,0m, respectively) and two overhangs (7,50m and 5,0m, respectively), spanning 82,5m. The investigated structural model is composed by a continuous tubular steel structure with welded connections supported by four double file steel columns. It is structurally composed of two plane trusses are intertwined by horizontal bracing set in upper and lower chord of the truss and slabs of concrete, forming effective composite with complete interaction. This structure is currently submitted to pedestrians and cyclists crossing. Experimental tests were carried out on the structural system and with the numerical results. For the numerical modeling, discretization techniques via finite element method were applied, based on the ANSYS program. The experimental results were analyzed according to the developed methodology, and a modal analysis was implemented to determine the dynamical properties: frequencies, mode shapes and modal damping ratio, while the structure results in terms of peak acceleration, was obtained and compared to the limit values proposed by several authors and design recommendations, for the structure performance by pedestrian walking regarding the acceptance criteria for human comfort.
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23

Mauger, François. "Double ionisation d' atomes soumis à des impulsions laser intenses : vue de l' espace des phases." Thesis, Aix-Marseille, 2012. http://www.theses.fr/2012AIXM4031.

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Lorsqu'ils sont soumis à des pulses laser courts et intenses, des atomes peuvent perdre des électrons. Plusieurs canaux sont impliqués dans la double ionisation, comme la NSDI et le scénario associé de la recollision. La recollision est maintenant vue comme la “pierre d'angle de la physique en champ fort” pour les éclairages qu'elle donne dans l'organisation de la matière et en ce qu'elle constitue l'une des manifestations les plus flagrantes de la corrélation électron-électron dans la nature. Dans ce manuscrit, une analyse théorique des mécanismes de double ionisation est menée en utilisant la mécanique classique. Cette description complémente les modèles quantiques en observant la dynamique depuis un cadre de travail différent et avec l'éclairage de la dynamique nonlinéaire. L'analyse, menée dans l'espace des phases, permet l'identification des structures organisatrices qui régulent les différents mécanismes d'ionisation. Pour des champs laser polarisés linéairement, le mécanisme de la recollision est complété par l'image de l'électron interne. L'électron interne donne accès à une description fine de la dynamique de recollision et explique les différentes routes pour la double ionisation. Il permet également de faire des prédictions telles que l'intensité du coude dans la probabilité de double ionisation et explique complètement la RESI. En polarisation circulaire, il est communément cru que la recollision n'est pas possible, en dépit de résultats expérimentaux contradictoires. En fait, l'analyse de l'espace des phases montre que la recollision est possible mais pas accessible à tous les atomes, réconciliant par conséquent les contradictions expérimentales précédentes
When subjected to strong and short laser pulses, atoms may lose electrons. Several ionization channels are involved in such double ionization events, like nonsequential double ionization (NSDI) and its associated recollision scenario. Recollision is now seen as the “keystone of strong field physics”, for its insights into the organization of matter, and is one of the most dramatic manifestations of electron-electron correlation in nature. In this manuscript a theoretical analysis of the double ionization mechanisms is carried out using classical mechanics. This description complements quantum treatments by observing the dynamics from a different framework, with the light of nonlinear dynamics, as both frameworks exhibit the main ingredient, i.e., strong electron-electron correlation. The analysis, carried out in phase space (e.g., through reduced models) enables the identification of the organizing structures that regulate the ionization channels. For linearly polarized lasers, the recollision mechanism is completed by the picture of the “inner” electron. The inner electron gives access to a fine description of the recollision dynamics and explains the routes to double ionization. It also enables verifiable predictions such as the location of the characteristic knee shape in the double ionization yield versus laser intensity and fully explains delayed ionizations like RESI. For circular polarization, it is commonly believed that recollision is not possible, despite apparently contradictory experimental results. In fact, the phase space analysis shows that recollision is possible but not accessible to all atoms, thus reconciling the previous experimental results
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24

Caixeta, Edielce Cristina. "Investigação experimental da fadiga em lajes de pontes com ou sem pré-lajes." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/3/3144/tde-20102010-151801/.

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As lajes dos tabuleiros de pontes de concreto armado, sejam elas maciças ou executadas com pré-lajes, são elementos estruturais suscetíveis à fadiga, devido às ações a que são submetidas. As pré-lajes, pelo fato de serem resultantes da junção de dois concretos diferentes, torna-se ainda mais suscetível à fadiga. Este trabalho apresenta estudos, ensaios e análise de resultados a respeito do comportamento à fadiga das lajes de pontes de concreto, sejam as maciças ou as executadas com pré-laje, armadas com barras ou telas soldadas. Foram realizados ensaios de fadiga de barra ao ar CA50 f10 mm isoladas e em telas para a construção da Curva de Wöhler nas condições brasileiras. Além disso, foram ensaiadas 23 lajes de concreto, sendo 6 lajes maciças e 17 executadas com prélajes, montadas com diversas configurações de armadura, submetidas a ensaios estáticos e dinâmicos. As configurações de armaduras adotadas nas lajes da pesquisa foram baseadas nas utilizadas com freqüência neste tipo de elemento das pontes, escala ½. Um dos principais motivos que levaram ao desenvolvimento desta pesquisa de caráter experimental foi a escassez de dados sobre o comportamento de lajes armadas com barras ou telas soldadas de fabricação brasileira, submetidas a ações cíclicas. Outro motivo foi a carência de estudos a respeito da iteração prélaje x capa. Foi verificado que não houve ruptura nessa região da estrutura devido aos carregamentos cíclicos aplicados no meio do vão. Ficou evidenciado também que as soldas das telas afetam sua resistência à fadiga.
Concrete bridge slabs, massive or pre-slabs, are structural elements susceptible to fatigue, due to loading applied to them. Pre-slabs, result of two different concretes, become even more susceptible to fatigue. This research presents the studies, tests and analysis of the results about the behavior of concrete bridge massive slabs or pre-slabs reinforced with steel bars and welded steel meshes due to fatigue loading. Axial testing in air of CA50 f10 mm in continuous bars and steel meshes were made in order to build the Wöhler Curve to the Brazilian conditions. Besides that, tests were made in 23 concrete slabs, 6 massive slabs and 17 preslabs, with several reinforcements arrangements, submitted to static and dynamic loading. The reinforcement configurations adopted in the slabs were based on the commonly used in these bridge elements in scale ½. One of main reasons that lead this experimental research development was the scarcity of data about the behavior of concrete slabs reinforced with rebars and welded mesh made in Brazil, submitted to cycle loading. Another reason was the lack of studies about the iteration between pre-slab and concrete cover. It was verified that no rupture was found in this region of the structure due to midspan cycle loading. The welding process caused loss of fatigue resistance.
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25

Almeida, Rogerio Rosa de. "Análise de vibrações em sistemas estruturais para pisos mistos com joists submetidos a atividades humanas rítmicas." Universidade do Estado do Rio de Janeiro, 2008. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=846.

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O aumento dos problemas de vibrações excessivas em estruturas civis oriundos de atividades humanas rítmicas tem conduzido à necessidade de desenvolvimento de critérios específicos para projetos sujeitos a ações dinâmicas rítmicas. Esta foi à motivação principal para o desenvolvimento de uma metodologia de análise centrada na resposta de um sistema estrutural submetido a cargas provenientes de atividades humanas rítmicas. Esta dissertação investiga o comportamento dinâmico de pisos compostos (aço- concreto) sujeito às atividades rítmicas provocadas pelas pessoas. O carregamento dinâmico foi obtido através de testes experimentais com indivíduos praticando atividades rítmicas e não rítmicas. A metodologia de análise proposta adota técnicas usuais de discretização presentes no MEF (Método dos Elementos Finitos), com base no emprego do programa Ansys. O sistema estrutural investigado consistiu em um ambiente de restaurante com uma área de dança adjacente. O modelo estrutural consiste de um piso suportado por treliças metálicas (joists) para longos vãos (14m) apoiados diretamente sobre paredes compostas por de blocos de concreto. O peso efetivo do sistema foi estimado como sendo de 3,6 kPa, incluindo 0,6 kPa para pessoas dançando e jantando. O momento de inércia efetivo dos joists foi da ordem de 1,6x106 mm4, baseando-se nas tensões suportadas. O estudo paramétrico considera uma correlação entre os resultados numéricos e analíticos. Os valores das acelerações de pico foram comparados com os limites recomendados por normas de projeto, baseando-se em critérios de conforto humano. Os resultados indicaram que os limites sugeridos pelas normas de projetos não foram satisfeitos. Tal fato indica que estas atividades rítmicas podem gerar picos de aceleração que ultrapassam os limites estabelecidos em recomendações de projeto.
The increasing incidence of building vibration problems due to rhythmic activities led to need of a specific design criterion for rhythmic excitations. This was the main motivation for the development of a design methodology centred on the structural system dynamical response submitted to dynamic loads due to human rhythmic activities. This dissertation investigated the dynamic behaviour of composite floor (steel- concrete) subjected to the human rhythmic activities. The used dynamic loads were obtained through experimental tests with individual carrying out rhythmic and non-rhythmic activities. The proposed analysis methodology adopted the usual mesh refinement techniques present in the finite element method (FEM) simulation implemented in the ANSYS program. The investigated structural system was used in a restaurant facility with an adjacent dancing area. The floor system consists of long span joist supported by concrete block walls. The floor effective weight was estimated including people dancing and dining. The floor effective weight was estimated to be equal to 3.6 kPa, including 0.6 kPa for people dancing and dining. The effective composite moment of inertia of the joists, was selected based on its required strength, ie: 1.1x106 mm4. The parametric study considered correlation between analytical and numerical results found in literature. The peak acceleration values were compared to limits proposed by design codes, based on human comfort and those values were not satisfied. Such fact indicated that these rhythmic activities could generate peak accelerations that surpass design criteria limits developed for ensuring human comfort.
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26

Silva, Irwing Aguiar Ribeiro da. "Modelagem do comportamento dinâmico e análise de fadiga de pontes rodoviárias mistas (aço-concreto)." Universidade do Estado do Rio de Janeiro, 2014. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=9076.

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Considerando-se os diversos carregamentos que solicitam a estrutura de uma ponte rodoviária, ao longo de sua vida útil, alguns possuem um comportamento essencialmente dinâmico, ou seja, variam com o tempo, diferentemente do que é considerado na prática corrente de projeto desse tipo de obra de arte. Em geral, os projetistas desse tipo de estrutura têm tratado carregamentos como o de vento, tráfego de veículos e de pedestres como ações de natureza estática, ignorando seu perfil cíclico. Tal consideração, em diversas situações de projeto, tende a minorar os efeitos das ações dinâmicas sobre o sistema estrutural. Além disso, estruturas submetidas a solicitações cíclicas, sob uma carga inferior à caga máxima suportada pelo material, estão sujeitas ao fenômeno da fadiga. A consideração adequada de todos estes aspectos mostra-se fundamentalmente importante para correta avaliação dos níveis de esforços solicitantes do sistema estrutural e, bem como, para a identificação de fenômenos importantes como o da fadiga que pode vir a provocar, por exemplo, a ruptura de componentes estruturais sem aviso prévio ou motivo aparente. Para tal, nesta dissertação as técnicas para a contagem de ciclos de tensão e a aplicação das regras de dano acumulado foram analisadas através de curvas do tipo S-N, associadas a diversas normas de projeto. A ponte rodoviária mista (aço-concreto) investigada neste estudo é constituída por seis vigas de aço longitudinais com enrijecedores transversais, oito transversinas e por um tabuleiro de concreto armado. O modelo numérico-computacional, desenvolvido para a análise dinâmica da ponte, foi elaborado com base em técnicas usuais de discretização através do método dos elementos finitos. As mesas e almas das vigas, assim como os enrijecedores , foram modelados por elementos de casca e laje de concreto armado, por elementos sólidos. O carregamento dinâmico avaliado no presente estudo diz respeito ao tráfego de veículos, cuja representação se dá a partir de sistemas "massa-mola-amortecedor". Os comboios formados são adotados como sendo semi-infinitos, deslocando-se com velocidade constante sobre a ponte. As conclusões da presente investigação versam acerca da vida útil de serviço dos elementos estruturais de pontes mistas (aço-concreto).
Considering the various shipments requesting the structure of a road bridge over its useful life, some are of an essentially dynamic behavior, ie , vary with time, contrary to what is considered standard practice in the design of this type of work of art. In general, the designers of this type of structure have treated loads such as wind, vehicles and pedestrians as traffic static nature of actions, ignoring their cyclical profile. This consideration, in various design situations, tends to mitigate the effects of dynamic actions on the structural system. Furthermore, structures subjected to cyclic requests under a lower load at maximum shits supported by the material, are subject to fatigue phenomenon. The proper consideration of these aspects is shown fundamentally important for accurate assessment of levels of internal forces in the structural system, as well as for the identification of important phenomena such as fatigue which may ultimately lead, for example, disruption of structural components without warning or apparent reason. To this end, this dissertation techniques for counting cycles of tension and enforcement of accumulated damage were analyzed by the type SN curves associated with various design standards. Mixed road bridge (steel-concrete) investigated in this study consists of six longitudinal steel girders with transverse stiffeners eight crossbeams and a deck of reinforced concrete. The numerical - computational model developed for the dynamic analysis of the bridge, was based on standard techniques of discretization by finite element method. The tables and souls of the beams, as well as the stiffeners were modeled by shell elements and reinforced concrete slab, for solid elements. The dynamic loading evaluated in this study relates to vehicular traffic, whose representation is given from "mass - spring - damper systems." Trains formed are adopted as semi - infinite, moving with constant speed on the bridge. The findings of this research Versam about the service life of the structural elements of composite (steel-concrete) bridges.
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27

Gregui, Ricardo Gratão. "Tenacidade à fratura dinâmica de ligas de titânio (Ti6AI4V) e de aço inoxidável (PH15-5)." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/18/18135/tde-17022016-122311/.

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O presente trabalho visou determinar a tenacidade à fratura dinâmica, KID, primeiramente pelos conceitos da Mecânica da Fratura Elástica Linear (MFEL) e posteriormente pela Mecânica da Fratura Elasto-Plástica (MFEP), JID, em materiais que em operação podem estar sujeitos a impactos em diferentes temperaturas. Os materiais estudados, de uso na indústria aeronáutica, foram uma liga de titânio Ti6Al4V (norma SAE AMS 4911), na condição recozida e uma liga de aço inoxidável PH 15-5 (norma SAE AMS 5659), na condição H1000. Os corpos de prova pré-trincados e entalhados foram retirados nas orientações L-T e L-S, a fim de que fossem determinadas e comparadas a relação tenacidade/densidade ou tenacidade específica dos materiais estudados. Em seguida os corpos de prova foram ensaiados sob condições de carga dinâmica em uma máquina de ensaio Charpy instrumentado, marca Instron-Wolpert PW30, conforme a norma ASTM-E23, com velocidade de carregamento de 5,52 m/s e nas temperaturas de 23 e 400ºC. Os valores das tenacidades, posteriormente comparados e correlacionados, foram obtidos de acordo com as expressões matemáticas mencionadas na literatura. A razão entre as energias estimadas de iniciação (Ei) e de propagação (Ep), (Ei/Ep), foi obtida a partir dos gráficos de carga-deslocamento x tempo. A determinação e caracterização dos aspectos macro e microscópicos da fratura foram realizadas através de microscopia ótica e de varredura. Em seguida, confrontaram-se os valores e os aspectos preponderantes dos mecanismos de fratura apresentados por cada material.
The present work aimed to evaluate the dynamic fracture toughness, KID, firstly using the Linear Elastic Fracture Mechanics parameter, (LEFM), and secondly using the Elasto-Plastic Fracture Mechanics (EPFM), JID. The materials used in this work are from aeronautic grade and are subjected to in service impact loads and temperature variation. The materials are a titanium alloy Ti6Al4V (standard SAE AMS 4911), in the annealed condition and a PH 15-5 stainless steel (standard SAE AMS 5659), H1000 condition. Both precracked and notched specimens were taken in the L-T and L-S directions, for the evaluation and comparison of the toughness/density ratio, i. e., the specific dynamic fracture toughness of the materials studied. Therefore, the specimens were tested under dynamic load using an Instron-Wolpert PW30 Instrumented Charpy Equipment, following the ASTM-E23 standard, with load speed of 5,52 m/s at 23 and 400ºC. The fracture toughness values were compared using mathematical expression from literature. The ration between the initiation (Ei) and propagation (Ep) energies, (Ei/Ep), was obtained from the load-displacement x time. The characterization of the macro and microscopic aspects of the fracture mechanisms were carried out using optical microscope and scan electronic microscope. The fracture toughness values and the fractographic observations were correlated and compared for the two materials studied.
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28

Alencar, Guilherme Santana. "Análise dinâmica e verificação à fadiga de obras de arte rodoviárias mistas (aço-concreto) submetidas ao tráfego de veículos sobre o pavimento irregular." Universidade do Estado do Rio de Janeiro, 2015. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=8772.

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As pontes rodoviárias metálicas e mistas (aço-concreto) são submetidas a um grande número de carregamentos repetitivos de diferentes magnitudes, ao longo do tempo. Estas ações dinâmicas podem causar a nucleação de fraturas ou mesmo a propagação destas sobre o sistema estrutural. A depender da magnitude, estes efeitos podem comprometer o sistema estrutural e a sua confiabilidade, além de reduzir a vida útil das pontes. Assim sendo, neste trabalho de pesquisa foi investigada a resposta dinâmica de uma ponte mista (aço-concreto), simplesmente apoiada, com vão de 40,0 m, submetida ao tráfego de veículos sobre a superfície irregular do pavimento. Para tal um modelo numérico representativo do sistema estrutural foi desenvolvido com base no emprego do programa ANSYS, por meio do uso de técnicas usuais de discretização, via método dos elementos finitos. Um estudo paramétrico foi desenvolvido para identificar, de forma qualitativa e quantitativa, o efeito das irregularidades do pavimento sobre o comportamento dinâmico da ponte mista investigada. Em seguida, a verificação do projeto à fadiga do sistema misto foi realizada, com base no emprego do algoritmo de contagem de ciclos Rainflow e em curvas S-N associadas às principais normas de projeto sobre o tema. As conclusões deste trabalho de pesquisa alertam aos engenheiros estruturais para a possibilidade concreta acerca do aumento do dano por fadiga, relacionado às ações dinâmicas de veículos trafegando sobre o tabuleiro de pontes em aço e mistas (aço-concreto).
Steel and steel-concrete composite highway bridges are currently subjected to dynamic actions with variable magnitudes due to the action of vehicles crossing on the deck. These dynamic actions can generate the nucleation of fractures or even their propagation in the structures. Depending on the magnitude, these effects can compromise the structural system response and the reliability, which may also lead to a reduction of the expected bridge service life. This way, the dynamic response of a steel-concrete composite bridge spanning 40 m was investigated in this work. The computational model, developed for the composite bridge dynamic analysis, adopted the usual mesh refinement techniques present in finite element method simulations, and was implemented in the ANSYS program. A parametric study was performed to identify the effect of vehicle speed and roughness pavement on the investigated bridge dynamic behaviour. The proposed methodology for evaluate the bridge service life to fatigue was based on a linear cumulative damage rule, Rainflow-counting algorithm and S-N curves from main design codes. Results of a parametric analysis are presented to verify the extension of the dynamical effects on highway bridges due to vehicles crossing on the irregular pavement surface. The main conclusions of this work focuses on alerting structural engineers to the possibility of increase of fatigue damage, related to steel and composite highway bridges when subjected to vehicle dynamic actions.
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29

Rimola, Bruno Dias. "Análise dinâmica de plataformas de aço para produção de petróleo com base na consideração do efeito da interação solo-estrutura." Universidade do Estado do Rio de Janeiro, 2010. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=2832.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Atualmente, as tendências competitivas do mercado mundial, têm forçado os engenheiros estruturais a desenvolver soluções de projeto que acarretem em menor peso e custo de execução. Uma consequência direta desta nova tendência de projeto é o aumento considerável de problemas relacionados a vibrações de piso indesejadas. Por esta razão, os sistemas estruturais de pisos podem tornar-se vulneráveis a vibrações excessivas, como por exemplo, aquelas induzidas por equipamentos mecânicos (máquinas rotativas). Deste modo, este trabalho objetiva investigar o comportamento dinâmico de uma plataforma de aço para produção de petróleo, localizada na bacia de Santos (campo de Merluza), São Paulo, Brasil. Para tal, investiga-se a influência das ações dinâmicas oriundas dos equipamentos mecânicos localizados sobre os decks metálicos da plataforma. A resposta dinâmica do modelo estrutural foi determinada através de um extenso estudo numérico, a partir da análise de suas frequências naturais, deslocamentos, velocidades e acelerações de pico. Nesta investigação, as cargas dinâmicas provenientes dos equipamentos mecânicos (máquinas rotativas) foram aplicadas sobre o piso metálico do sistema estrutural. Com base obtenção da resposta dinâmica da estrutura (deslocamentos, velocidades e acelerações), foi possível avaliar a performance do modelo estrutural em termos de critérios de conforto humano e das tolerâncias máximas referentes aos equipamentos mecânicos, de acordo com normas e recomendações de projeto.
Nowadays, the competitive trends of the world market have long been forcing structural engineers to develop minimum weight and labor cost solutions. A direct consequence of this new design trend is a considerable increase in problems related to unwanted floor vibrations. For this reason, the structural floors systems can become vulnerable to excessive vibrations, for example, produced by impacts such as mechanical equipments (rotating machinery). This way, the present paper investigated the dynamic behavior of a production platform made of steel and located in Santos bay (Merluza field), São Paulo, Brazil. Mechanical equipments were located on the steel decks of the structural model, related to electrical generators. This way, this research investigates the influence of the dynamic actions induced by mechanical equipments located on the steel floor of the platform. The dynamic response of the structural model was determined through an extensive numerical study, from the analysis of its natural frequencies, displacements, velocities and peak accelerations. In this study, the dynamic loads induced by the mechanical equipments (rotating machinery) were applied on the steel floor of the structural system. Based on the structural dynamic responses (displacements, velocities and accelerations) obtained, it was possible to evaluate the performance of the structural model in terms of the human comfort criteria and maxim tolerances related to the mechanical equipments, according to the design.
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30

Dantas, João Paulo Ribeiro. "Investigação experimental da fadiga em lajes de pontes armadas com barras ou telas soldadas." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/3/3144/tde-20102010-160417/.

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Este trabalho apresenta estudos, ensaios e análises de resultados a respeito do comportamento à fadiga das estruturas de concreto armadas com barras isoladas e telas soldadas, começando pelas lajes de pontes, seus elementos mais sensíveis à fadiga. A parte experimental desta pesquisa consiste na investigação experimental do comportamento à fadiga de lajes de concreto armado, executadas com e sem pré-lajes armadas com barras de aço isoladas ou em tela soldada. Foram realizados ensaios de fadiga de barra ao ar em 36 corpos de prova de CA50 f10 mm, isoladas e em tela, com o objetivo de construir a Curva de Wöhler dessas barras de produção nacional. Além disso, foram ensaiadas 20 lajes executadas com e sem pré-lajes de concreto, montadas com diversas configurações de armadura, submetidas a ensaios estáticos e dinâmicos. A configuração de armadura adotada nas lajes da pesquisa foi baseada nas utilizadas com freqüência neste tipo de elemento das pontes. A escassez de dados precisos a respeito do comportamento de lajes armadas com barras ou com telas soldadas de fabricação brasileira submetidas a ações cíclicas conduziu ao propósito de se elaborar uma pesquisa de caráter experimental sobre esse tema, cujos resultados e conclusões pudessem fornecer informações mais precisas a respeito do desempenho das lajes.
This research presents the studies, tests and the analysis of the results about the behavior of concrete structures reinforced with rebars or steel mesh due to fatigue loading, starting with bridge slabs which are the most susceptible elements to fatigue. The experimental part of this research consists in testing the behavior due to fatigue of concrete slabs, with or without pre-slabs and reinforced with continuous bars or steel mesh. Axial testing in air of 36 specimens of CA50 f10 mm in continuous bars and mesh were made in order to build the Wöhler Curve for Brazilian conditions. Beyond that, tests were made in 20 concrete slabs with pre-slabs, with several reinforcements arrangement. The 20 slabs were submitted to static and dynamic loading. The reinforcement configuration was based on the commonly used for these elements. The scarcity of more precise data about the behavior of concrete slabs reinforced with rebars or welded mesh made in Brazil submitted to cycle loading was the major reason to make a research based on the testing results about this theme, which results and conclusions are capable of producing more accurate information about the behavior of the slabs.
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31

Mello, Antonio Vicente de Almeida. "Vibrações em pisos de edificações induzidas por atividades humanas." Universidade do Estado do Rio de Janeiro, 2005. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=418.

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Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro
Atualmente, as novas tendências arquitetônicas e as exigências de mercado, vêm conduzindo a engenharia estrutural na busca por soluções cada vez mais arrojadas, as quais exigem grande experiência e conhecimento dos projetistas estruturais aliados a utilização de novos materiais e tecnologias. Esta filosofia de concepção estrutural está inserida em uma das mais importantes tendências de projeto dos últimos anos, ou seja: a busca por sistemas estruturais de rápida execução, dotados de peças de menor peso próprio e que possam vencer grandes vãos com um mínimo de elementos verticais, permitindo assim uma maior flexibilidade na adequação de ambientes. Por outro lado, esta filosofia de projeto tem conduzido a elementos estruturais cada vez mais esbeltos e com freqüências naturais cada vez mais baixas e, por conseguinte, mais próximas das faixas de freqüência das excitações dinâmicas associadas às atividades humanas, tais como: andar, correr, pular, etc. Devido as razões expostas no parágrafo anterior, os sistemas estruturais de engenharia tornaram-se bastante vulneráveis aos efeitos de vibrações induzidas por pequenos impactos como é o caso do caminhar de pessoas sobre pisos, resultando em desconforto para as pessoas. Deve-se destacar, ainda, que tais considerações de projeto têm atendido aos estados limites últimos. Todavia, os estados limites de utilização desses sistemas estruturais precisam ser analisados, sem sombra de dúvida, de maneira mais criteriosa. Deste modo, no sentido de contribuir para fornecer subsídios aos engenheiros estruturais, no que tange a análise dinâmica de estruturas submetidas a excitações induzidas pelos seres humanos, são desenvolvidos diversos modelos de carregamento representativos do caminhar das pessoas. A variação espacial e temporal da carga dinâmica é considerada ao longo da análise e, bem como, o efeito transiente do impacto do calcanhar humano nos pisos é levado em conta. Assim sendo, são considerados nesta dissertação diversos modelos estruturais associados a pisos mistos (aço-concreto). Técnicas usuais de discretização, com base no emprego do Método dos Elementos Finitos (MEF), via utilização do programa computacional Ansys, são consideradas neste estudo. Uma análise extensa acerca da resposta dinâmica dos pisos é feita, mediante o emprego dos modelos de carregamento desenvolvidos, principalmente, em termos dos valores das acelerações. Na seqüência, os resultados encontrados são comparados com aqueles fornecidos pela literatura técnica disponível sobre o assunto sob o ponto de vista associado ao conforto humano. Investiga-se, também, a influencia da variação de parâmetros estruturais sobre a resposta dinâmica dos modelos, tais como: comprimento vão, taxa de amortecimento, espessura das lajes e, ainda, rigidez das ligações viga coluna. Os resultados obtidos ao longo do estudo indicam, claramente, que os projetistas estruturais devem ser alertados para distorções importantes que ocorrem quando as normas de projeto são utilizadas sem o devido cuidado. Um outro importante diz respeito ao fato de que em diversos pisos analisados observa-se que os critérios de conforto humano não são satisfeitos, demonstrando a importância da consideração dos efeitos dinâmicos provenientes dos seres humanos na análise desse tipo de problema.
Nowadays, the new architectural tendency and the market requirements, are leading structural engineering in the search for bolder solutions, which demands great experience and knowledge of the structural designers associated to the use of new materials and technologies. This philosophy of structural conception is inserted in one of the most important trends of project of the last years that means: the search for structural systems of fast execution, endowed with parts of lower weight and that can be successfully large with a minimum of vertical elements, thus allowing a higher flexibility in the ambients adequacy. On the other hand, this project philosophy has lead to structural elements more and more slender and with natural frequencies much and much lower and, therefore, closer to the frequency of the dynamic excitation associated to the human beings activities, such as: walking, running, jumping, etc. Due to the reasons described in the previous paragraph, the structural engineering systems became sufficiently vulnerable to the effects of vibrations induced by small impacts as it is the case of walking of people on floors, resulting in discomfort to the people. It must be highlighted, also, that such project considerations have fulfilled the required limit states. However, the limit states of use for these structural systems need to be analysed, with no doubt, in a more sensible way. In this way, willing to contribute to supply subsidies to the structural engineers, in the dynamic analysis of structures subject to excitation induced by human beings, several loads models are developed to represent the act of walking. The space and time variation of the dynamic load is considered through the analysis and the transient effect of the impact of the human heel on the floor is taken into consideration, as well. In this way, It is considered in this dissertation, several structural models associated to composite floors (steel-concrete). In this study, it was considered the usual techniques of discretization, based on the Finite Element Method (FEM) using the computer program Ansys. An extensive analysis concerning the dynamic response of the floors is made, by means of the application of the developed load models, mainly, in terms of the values of the accelerations. The results obtained are compared to those supplied by the techinical literature available about the subject with the point of view associated to the human comfort. It is also investigated, the influence of the structural parameter variation on the dynamic response of the models, such as: span length, damping ratio, thickness of the slab and, also, rigidity of the beam columns. The results obtained along the study clearly indicate that the structural designers must be alerted to important distortions that may occur when the project rules are used without the necessary caution. Another important remark is regarded to the fact that in several analysed floors it is observed that the criteria of human comfort are not satisfied which demonstrate the importance of the consideration of the dynamic effect caused by human beings in the analysis of this type of problem.
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32

Bastos, Paulo Sérgio dos Santos. "Análise experimental de dormentes de concreto protendido reforçados com fibras de aço." Universidade de São Paulo, 1999. http://www.teses.usp.br/teses/disponiveis/18/18134/tde-17022005-165347/.

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Este trabalho descreve um dormente monobloco de concreto protendido, o qual foi projetado para atender as características de uma via ferroviária brasileira. O dormente apresentou comportamento e resistência semelhantes aos dormentes de concreto comumente fabricados em vários países. A fim de verificar e aprovar o projeto, o dormente foi submetido a ensaios estáticos e dinâmicos, segundo as especificações da norma americana AREMA. Verificado e aprovado o projeto, dezoito dormentes foram fabricados sem e com fibras de aço, no teor de 60 kg/'M POT.3' (aproximadamente 0,75 % por volume). Ensaios estáticos e dinâmicos foram realizados em dormentes com e sem fibras de aço, com o objetivo de quantificar o benefício das fibras de aço à resistência estrutural do dormente. As fibras aumentaram o momento fletor de primeira fissura e o momento último, aumentaram significativamente a força de início de escorregamento dos fios de protensão e reduziram o espaçamento e a abertura das fissuras. As fibras também acrescentaram grande ductilidade aos dormentes e diminuíram a tensão nos fios de protensão, nos estágios mais avançados do carregamento. Sob ação dinâmica, as fibras reduziram a tensão nos fios de protensão mais tracionados em aproximadamente 100%, o que elevou significativamente a resistência do dormente à fadiga. Dormentes fabricados com menor força de protensão apresentaram excelente comportamento plástico e grande ductilidade, especialmente o dormente com fibras
This work describes a prestressed concrete monoblock railway sleeper designed according to a brazilian railway track. The sleeper was tested according to the Arema specifications in order to verify the project. The sleeper presented a structural behavior similar to the concrete railway sleepers used worldwide. After the preliminary tests, eighteen sleepers were manufactured without and with steel fibers contents of 60 Kg/'M POT.3' (about 0.75% by volume) and they were tested under static and dynamic loading to evaluate the fiber contribution on the resistance. Steel fibers increased the first crack and ultimate bending moments, reduced the deflection under ultimate load and increased significantly the slip force of the prestressing tendons. Reinforcing the sleeper with fibers also reduced the crack width and the spacing between cracks, adding higher ductility to the sleepers and decreasing the stress in the prestressing tendons under higher loads. The fibers increased significantly the fatigue strength under cyclic loading, decreasing the stress in the prestressing tendons in about 100%. The test results showed that sleepers manufactured with lower prestressed force have higher toughness, especially those reinforced with steel fibers
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33

Lima, Nelson Luiz de Andrade. "Efeito da modelagem do carregamento, do impacto do calcanhar humano e do amortecimento estrutural na resposta dinâmica de passarelas mistas." Universidade do Estado do Rio de Janeiro, 2007. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=590.

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Considerando-se as exigências impostas por projetos arquitetônicos cada vez mais arrojados as passarelas de pedestres têm sido comumente projetadas cada vez mais leves e com grandes vão livres. Este procedimento tem gerado sistemas estruturais bastante esbeltos e os estados limites últimos e de utilização que norteiam o dimensionamento tem sido modificados. Uma outra conseqüência desta tendência de projeto diz respeito a um aumento considerável dos problemas referentes à vibração. No caso particular de passarelas, este fenômeno ocorre quando a freqüência fundamental da estrutura é igual ou se aproxima da freqüência do passo do pedestre. Atividades como caminhar, correr ou pular produzem excitações dinâmicas. Essas forças dinâmicas, em determinados casos, podem vir a produzir níveis de vibração elevados e, por conseguinte, perturbar ou até mesmo alarmar as pessoas que estiverem utilizando a estrutura. Como o propósito primário das passarelas é o transporte de pedestres, as mesmas precisam estar seguras e apresentar um comportamento que não ofereça desconforto aos usuários. Tendo em mente todos esses aspectos, o desenvolvimento desta dissertação tem como objetivos o estudo da influência da modelagem do carregamento dinâmico, proveniente dos pedestres, impacto do calcanhar humano e, bem como, do amortecimento estrutural sobre a resposta dinâmica de passarelas mistas (aço-concreto). Para tal, um modelo mais realista que incorpora as ações dinâmicas induzidas pelos pedestres, de modo a considerar o impacto transiente do calcanhar dos mesmos será objeto de estudo na presente investigação. Neste modelo de carregamento, o movimento de pernas que causa a subida e descida da massa efetiva do corpo em cada passo foi considerado e a posição do carregamento dinâmico foi alterada de acordo com a posição do individuo, assim a função de tempo, correspondente a excitação induzida pela caminhada, teve uma variação espacial e temporal.O modelo estrutural utilizado baseia-se no projeto de diversas passarelas mistas (aço-concreto). A resposta dinâmica das passarelas, em termos das acelerações verticais de pico e rms (root mean square), é obtida e comparada com os valores limites propostos por normas de projeto, objetivando a verificação do conforto humano. Com base nos resultados alcançados nesta dissertação foi possível demonstrar a importância dos parâmetros investigados (modelagem da carga dinâmica, efeito do calcanhar humano e amortecimento estrutural) e como estes influenciam substancialmente na avaliação da resposta dinâmica das passarelas. Os resultados obtidos ao longo do estudo indicam, claramente, que os projetistas estruturais devem ser alertados para distorções importantes que ocorrem quando os efeitos dinâmicos são desprezados na análise deste tipo de estrutura. Os valores máximos de acelerações encontrados violam os critérios de conforto humano quando comparados com aqueles previstos em diversas recomendações de projeto. Portanto, verifica-se que as passarelas de pedestres podem atingir níveis de vibração elevados os quais podem comprometer o conforto humano e a segurança dos usuários da obra.
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34

Gonçalves, Sidclei Gomes. "Análise dinâmica não-linear de pisos mistos (aço-concreto) submetidos a ações humanas rítmicas." Universidade do Estado do Rio de Janeiro, 2011. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=7463.

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Atualmente, o crescimento dos problemas de vibrações excessivas sobre pisos mistos (aço-concreto) tem conduzido à necessidade de desenvolvimento de critérios específicos para projetos estruturais submetidos à ação de atividades humanas rítmicas. Com base no desenvolvimento desta dissertação de mestrado, objetiva-se, principalmente, verificar a influência das ligações estruturais (ligações viga-viga), sobre a resposta dinâmica não-linear de pisos mistos (aço-concreto) de edificações, quando submetidos a cargas dinâmicas humanas rítmicas. Deste modo, o carregamento dinâmico empregado para a simulação das atividades humanas sobre o modelo estrutural investigado foi obtido através de testes experimentais com indivíduos praticando atividades rítmicas e não rítmicas. O modelo analisado nesta dissertação corresponde a um piso misto (aço-concreto) com uma área total de 1600m2 e consiste de um ambiente onde serão desenvolvidas atividades de ginástica aeróbica. O sistema estrutural é constituído por lajes de concreto armado apoiadas sobre vigas de aço, simulando o comportamento de um sistema estrutural misto (aço-concreto) com interação total. A metodologia de análise desenvolvida emprega técnicas usuais de discretização presentes no método dos elementos finitos, com base no emprego do programa ANSYS. A modelagem do sistema contempla ligações estruturais do tipo rígidas, semirrígidas e flexíveis. Os valores das acelerações de pico foram comparados com os limites recomendados por normas de projeto, baseando-se em critérios de conforto humano. As conclusões alcançadas ao longo deste trabalho de pesquisa revelam que as ligações estruturais do tipo viga-viga não apresentam influência significativa, no que diz respeito a resposta dinâmica não-linear da estrutura. Por outro lado, as acelerações de pico obtidas com base na análise dinâmica não-linear apresentam valores elevados indicando que o piso misto (aço-concreto) investigado apresenta problemas de vibração excessiva inerentes ao conforto humano.
Nowadays, the increasing incidence of composite (steel-concrete) floors vibration problems due to human rhythmic activities led to a specific design criteria to be addressed in structural design. The main objective of this investigation is to evaluate the influence of the structural connections (beam-to-beam connections) on the composite floors nonlinear dynamic response, when submitted to human rhythmic dynamic loads. The dynamic loads were obtained through experimental tests with individuals carrying out rhythmic and non-rhythmic activities. The investigated structural model was based on building composite floors and consisted of a typical office building interior bay with a total are of 1600m2 used for aerobics. The structural system are composed of a composite (steel-concrete) solution made of an I steel profile and a reinforced concrete slab. In this investigation a complete interaction between the concrete slab and steel beams was considered. The proposed analysis methodology adopted the usual mesh refinement techniques present in the finite element method simulations implemented in the ANSYS program. The structural system finite element modelling have considered rigid, semi-rigid and pinned beam-to-beam joints. The peak accelerations were compared with limits proposed by design codes and recommendations, based on human comfort criteria. The results obtained in this investigation indicated that the structural connections (beam-to-beam connections) can have a relevant influence on the composite floor nonlinear dynamic response. On the other hand, the peak accelerations obtained in this investigation, based on a nonlinear dynamic analysis, indicated that the investigated composite floor violated the human comfort criteria, as well as its vibration serviceability limit states.
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35

Al-Hasani, Firas Ali Jawad. "Multiple Constant Multiplication Optimization Using Common Subexpression Elimination and Redundant Numbers." Thesis, University of Canterbury. Electrical and Computer Engineering, 2014. http://hdl.handle.net/10092/9054.

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The multiple constant multiplication (MCM) operation is a fundamental operation in digital signal processing (DSP) and digital image processing (DIP). Examples of the MCM are in finite impulse response (FIR) and infinite impulse response (IIR) filters, matrix multiplication, and transforms. The aim of this work is minimizing the complexity of the MCM operation using common subexpression elimination (CSE) technique and redundant number representations. The CSE technique searches and eliminates common digit patterns (subexpressions) among MCM coefficients. More common subexpressions can be found by representing the MCM coefficients using redundant number representations. A CSE algorithm is proposed that works on a type of redundant numbers called the zero-dominant set (ZDS). The ZDS is an extension over the representations of minimum number of non-zero digits called minimum Hamming weight (MHW). Using the ZDS improves CSE algorithms' performance as compared with using the MHW representations. The disadvantage of using the ZDS is it increases the possibility of overlapping patterns (digit collisions). In this case, one or more digits are shared between a number of patterns. Eliminating a pattern results in losing other patterns because of eliminating the common digits. A pattern preservation algorithm (PPA) is developed to resolve the overlapping patterns in the representations. A tree and graph encoders are proposed to generate a larger space of number representations. The algorithms generate redundant representations of a value for a given digit set, radix, and wordlength. The tree encoder is modified to search for common subexpressions simultaneously with generating of the representation tree. A complexity measure is proposed to compare between the subexpressions at each node. The algorithm terminates generating the rest of the representation tree when it finds subexpressions with maximum sharing. This reduces the search space while minimizes the hardware complexity. A combinatoric model of the MCM problem is proposed in this work. The model is obtained by enumerating all the possible solutions of the MCM that resemble a graph called the demand graph. Arc routing on this graph gives the solutions of the MCM problem. A similar arc routing is found in the capacitated arc routing such as the winter salting problem. Ant colony optimization (ACO) meta-heuristics is proposed to traverse the demand graph. The ACO is simulated on a PC using Python programming language. This is to verify the model correctness and the work of the ACO. A parallel simulation of the ACO is carried out on a multi-core super computer using C++ boost graph library.
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36

Hsu, Chun-Chih, and 許純芝. "Ultrafast photoisomerization dynamics of azo dye in solution and a polymer film." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/19137824936481896647.

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碩士
國立交通大學
電子物理系所
97
The photoisomerization of 4’-[(N,N-Dihydroxyethyl)amino]-nitroazobenzene (Disperse Red 19) in solution and in polymer film are investigated by femtosecond time-resolved absorption spectroscopy. Using broadband sub-10 fs visible pulses, the dynamics of electronic relaxation and molecular vibrations are observed in both samples. The motion of a wavepacket in the excited state out of the Franck-Condon state occurs on the time scale of ~100 fs. The excited state relaxation occurs with time constant of 0.63 ps in solution and 0.84 ps in polymer films. For a solution and a polymer film, the vibrational cooling in the ground state proceeds are 2.55 ps and 4.43 ps, respectively, suggesting that the isomerization dynamics are sensitive to the molecular environments. To the best of our knowledge, this work is the first experimental observation for the ultrafast processes of DR19 in different molecular environments.
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37

"Ab initio molecular dynamics studies on thermal decomposition of Azomethane and fluxionality of IF₇, IOF₆⁻ and Te₇⁻." 2001. http://library.cuhk.edu.hk/record=b5890706.

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Hon Wan Chee Nicole Wendy.
Thesis (M.Phil.)--Chinese University of Hong Kong, 2001.
Includes bibliographical references (leaves 85-87).
Abstracts in English and Chinese.
THESIS COMMITTEE --- p.ii
ABSTRACT (English version) --- p.iii
ABSTRACT (Chinese version) --- p.v
ACKNOWLEDGEMENTS --- p.vii
TABLE OF CONTENTS --- p.viii
LIST OF FIGURES --- p.x
LIST OF TABLES --- p.xiii
Chapter CHAPTER 1. --- General Introduction
Chapter Section 1.1 --- Introduction --- p.1
Chapter Section 1.2 --- Electronic Structure Calculation --- p.2
Chapter Section 1.3 --- Molecular Dynamics --- p.10
Chapter CHAPTER 2. --- Ab Initio Molecular Dynamics Study on Thermal Dissociation of Azomethane
Chapter Section 2.1 --- Introduction
Chapter Section 2.2 --- Computational Method --- p.17
Chapter Section 2.3 --- Results and Discussion --- p.21
Chapter Section 2.4 --- Conclusion --- p.47
Chapter CHAPTER 3. --- "Ab Initio Molecular Dynamics Study on Fluxionality of IF7, TeF7- and iof6-"
Chapter Section 3.1 --- Introduction --- p.49
Chapter Section 3.2 --- Computational Method --- p.52
Chapter Section 3.3 --- Analysis --- p.55
Chapter Section 3.4 --- Results and Discussion --- p.56
Chapter Section 3.5 --- Conclusion --- p.83
REFERENCES --- p.85
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38

Ichilmann, Sachar. "Nondestructive Investigation of Guest Evaporation and Dynamics in Nanoporous Hosts." Doctoral thesis, 2016. https://repositorium.ub.uni-osnabrueck.de/handle/urn:nbn:de:gbv:700-2016020814218.

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Non-destructive investigation methods where applied to study evaporation dynamics and other dynamic processes of volatile and non-volatile fluids from different porous membranes. While evaporation dynamics from porous alumina didn't show any irregularities, it was shown that evaporation of ethanol from porous glasses can be divided into two different phases - linear endothermal evaporation and adiabatic burst evaporation.
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39

Liu, Bao-yi, and 劉寶義. "Combination of ACO and PSO algorithms for solving dynamic cell formation problems." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/45953607356830875849.

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碩士
大同大學
資訊經營學系(所)
98
Cellular manufacturing system (CMS) is one of the most effective approaches to deal with the requirements of manufacturing small amount and large-variety products. The most important step in the design of CMS is to solve the cell formation problems (CFP). The main idea of most CFP approaches is to cluster similar parts into part families and cluster machines into machine cells concurrently in order to reduce the transportation cost of parts among machine cells in the production stage. In the past decades, most of the CFP approaches need the number of clusters to be given beforehand, and very few papers focus on dynamic cell formation problems (DCFP). Therefore, this paper proposes a new algorithm based on the ant colony optimization (ACO) algorithm and particle swarm optimization (PSO) algorithm to solve the dynamic CFP. Performance evaluation of the proposed approach is conducted by testing five CFP cases selected from the literature. The results of testing show that the proposed approach can solve the dynamic CFP very well.
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40

Huang, Jiahui, and 黃家輝. "Effects of dynamic inflow on biological nutrient removal of an A2O system." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/96212528989640743475.

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碩士
國立暨南國際大學
土木工程學系
94
Abstract Activated sludge system is a non-linear and complicated system. For biological nutrient removal (BNR), dynamic loading of the influent results in dynamic variation of effluent. For operators of wastewater treatment plants, they have to daily maintain the stability of the activated sludge system under dynamic loading of influent. It is also necessary to prevent the system from sludge bulking, washout and the decrease of treatment efficiencies. If the activated sludge system is operated basing on steady-state, it is difficult to well control the dynamic characteristics of effluent and to achieve the objective of a BNR system. In this research, an A2O pilot plant was used to acclimatize activated sludge under different influent patterns and concentration for simulating domestic wastewater treatment plant. The pattern of recyclable nitrified water and recyclable sludge were simultaneously varied to control sludge pre-recycle for BNR. The artificial neural network and grey theory were further used to describe the metabolism of microorganism and to predict the effluent of BNR under dynamic loading of influent. Then, the prediction abilities of the artificial neural network and grey theory were further compared in the study. Basing on type1, type2 and type3 control strategies, the results indicated that the removal efficiencies of soluble COD were 92%, 94% and 92%, respectively; the removal efficiencies of ammonia nitrogen were 78%, 90% and 95%, respectively; the denitrification rates were 77%, 74% and 83%, respectively; the removal efficiencies of phosphate were 22%, 57% and 14%, respectively. The type2 control strategy was the best one. On the type2 control strategy, it was found that MLSS concentration during higher loading periods was higher than overall average MLSS concentration. During lower loading periods, MLSS concentration was lower than overall average MLSS concentration. The Type2 control strategy achieved the objective of sludge pre-recycle control. The data set of water quality obtained from all kinds of control strategy was used to train and test both of the models (the artificial neural network and grey theory). Coefficient of correlation (R), mean absolute percentage (MAPE) and root mean square (RMS) between experimental data and predicted data were used to evaluate the fitness of the model. It was obviously found that the artificial neural network was more appropriate for predicting the dynamic behaviors of the A2O system. Then, the sensitivity analysis was further used to comprehend the influence of each variable on the effluent and the internal variation of the A2O system.
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41

Wei, Chen-Chi, and 魏振吉. "The Empirical Research of Dynamic Capability Lifecycle：A Case Study of AUO Corporation." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/19829129157843507916.

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碩士
中原大學
企業管理研究所
95
Teece et al.(1997) think organization must built dynamic capability, it can ensure sustaining competition advantage. The ‘dynamic capabilities’ emphasizes the key role of strategic management in appropriately adapting, integrating, and reconfiguring internal and external organizational skills, resources, and functional competences to match the requirements of a changing environment. Helfat (2003) define the capability lifecycle includes several stages. The lifecycle of a new capability in a new-to-the world organization begins with the founding stage, which lays the basis for subsequent development of the capability. A development stage follows this initial stage, marked by gradual building of the capability. Eventually, capability building ceases and the capability reaches the maturity stage. This thesis study AUO Corporation to understand the forming background, the process of growing, and how to apply the dynamic capabilities to build the competition advantage. Finally, the evolution of dynamic capabilities can be recognized. The finding of this thesis showed the AUO Corporation has efficient in the coordinating of the internal resource, and to know the change of environment to get complementary resource, to build the competition advantage
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42

Jheng, Ke-Wun, and 鄭克文. "The Study of Applying High Efficient ACO to Multi-term Dynamic Asset Allocation." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/84270471479000898166.

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碩士
國立暨南國際大學
資訊管理學系
95
Thanks to the advance progress of the liberalization, diversification and internationalization of the economics in Taiwan, more and more people begin to invest the money to the marketing. On the other hand, because of the decreasing of the interests and the inflation, how to make proper asset allocation to ensure the increase the wealth has became an important issue. Many of the researches have been done on this issue, yet, most of them use constant asset ratio for the entire simulation and ignore the variations of the financial marketing. This study uses the Ant Colony Optimization as a tool to simulate the multi term dynamic asset allocation financial model, trying to find out what are the best asset combinations for largest profits. Because of the complexity of this financial model, it takes a lot computation even the hardware of the computer has much improved. And, in order to maintain the solution accuracy, no any simplification assumptions have been imposed to the model. Thus, to find the accurate solution in timely fashion, this study embeds the parallel environments with Message Passing Interface (MPI) to the entire simulation. Through the multi CPU computational power, the optima asset allocation ratios can be obtained efficiently and accurately. The calculated solutions are compared to those of the traditional evaluation methods, such as the Buy-and-Hold, Constant Mix, Constant Proportion Portfolio Insurance and Time-Invariant Portfolio Protection. It shows that the results from ACO simulation optimization algorithm are superior to those from the four traditional approaches.
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43

Li, Zong-Lin, and 李宗霖. "Development and establishment of system dynamics model of aerobic tank and membrane tank in modified A2O system." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/db8rxs.

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碩士
國立中央大學
環境工程研究所
106
The modified A2O activated sludge treatment system removes carbon, nitrogen and phosphorus from water by microbial action to meet the flow standard. Generally, the A2O wastewater treatment system is a semi-open system, and changes in the external environment will affect the water quality characteristics of the sewage, thereby affecting the treatment efficiency. Failure to properly control the water quality in a timely manner may result in deterioration of the outflow water quality. This study uses the concept of system dynamics to analyze the reaction mechanism between various substances and microorganisms in the system, and based on this, develops and establishes the dynamic mode of the aerobic tank and membrane filter system of the modified A2O system. At the same time, the rate of microbial reaction in the model is estimated by using artificial neural network. Compare the simulation results with the actual outflow water quality data, the relative error between the simulation results of MLSS, ammonia nitrogen, nitrate nitrogen and orthophosphate is 3.57%~196.65%, and the absolute error is less than 8.1919mg/L, which is an allowable error range. This result indicates that the model can effectively estimate the concentration of the substance. The absolute error of the simulated concentration and actual concentration of SCOD is 24.07 mg/L, and the simulation results are not as good as other water quality project estimation results, which may be caused by the gradual accumulation of errors in the SCOD estimation results in a single tank. When the data of the second experiment is used for simulation, the error between the simulation result and the actual data increases. Comparing the two experimental data, although the influent water quality has changed, it is oscillated around the first batch of experimental data. Therefore, the judgment caused the error because the system phase changes.
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44

Wang, Hong-Miao, and 汪虹妙. "Development and establishment of system dynamics model of anaerobic tank and anoxic tank in modified A2O system." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/gczd8d.

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碩士
國立中央大學
環境工程研究所
106
The modified A2O system is connected by anaerobic tank, anoxic tank, aerobic tank and membrane bioreactor(MBR) to treat urban domestic sewage, and this research object is anaerobic tank and anoxic tank. Since the operators of sewage treatment plant are used to take fixed operation and control method, and the sewage treatment system design is used to the steady state mathematical model, it cannot cope with the dynamic sewage treatment system with the influent water quality and quantity changing with time. This study will integrate the system dynamics model of non-structural problems, combined with the adaptive learning ability, nonlinear mapping ability and fault tolerance of the artificial neural network, integrated into the system dynamic model of the modified A2O system can find out the cause of the anaerobic tank and the anoxic tank problem. It is expected not only to improve the stability of the outflow water quality, but also to improve the normal operation of the modified A2O system for subsequent system operation, control, maintenance and management. The anaerobic tank and anoxic tank system dynamic model in modified A2O system established in this study is more feasible under continuous water quality testing and monitoring conditions. And we through the system dynamic model find the cause of the system problem and simulate the model under different conditions, to develop the operation and control strategy of problem in modified A2O system.
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45

Chow, Bo-Kai, and 邱柏楷. "The Study of Dynamic Competition in Taiwan’s Panel Industry – Case Studies of AUO and InnoLux." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/vc8hcc.

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碩士
國立政治大學
科技管理與智慧財產研究所
107
AUO and InnoLux, two Taiwanese panel factories, have exported one of the most pieces of panel in the world. In 2017, both companies’ revenue reached more than 30 billion NTD; though having around 60 billion NTD of liability in 2011. As we know, few years ago, AUO and InnoLux suffered from an unscrupulously underpricing among competitors and was regarded as an awful performing in their businesses. Nevertheless, as time went by, it seems obvious that both of the companies have found out their niche market in the panel industry. What are the strategies made by AUO and InnoLux respectively and how these strategies changed this competitive situation? The dynamic competitive perceptive is utilized in this thesis to figure out the answer of the question stated above. What’s more, instead of one-time competition, this research is going to put more emphasis on “feedback loop”, which means multi-run rivalry. With feedback loop, the research can tell more specific about what the effect of the strategy was and how it changed the competitive situation of them. Before 2014, both companies tried to get the order as large amount as possible while the profit was low, causing the unstable income and satisfaction of both companies’ performance. After that, AUO decided to dedicate to niche market (commercial panel); since InnoLux dug in medium & small size panel. From then on, the two companies set themselves on different paths. The aim of the research is not only to explain the reborn of AUO and InnoLux in a systematic way, but also point out a different view of the dynamic competitive structure.
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46

陳鈺菁. "Spectroscopy and Relaxation Dynamics of Protoporphyrin(IX) Zinc(II) in Solutions, inside AAO Nanotubes and in Combination with Apomyoglobin." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/84794992175849924489.

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碩士
國立交通大學
應用化學系所
93
The aggregation behaviors of Protoporphyrin (IX) Zinc (II) (ZnPP) in solutions, inside anodized aluminum oxide (AAO) nanoporous environments, and in combination with apomyoglobin (Apo-Mb) have been observed by using time-correlated single photon counting (TCSPC) technique. In ZnPP / THF solution, we observed a new band in addition to the Q (0,0) and Q (0,1) bands in the emission spectrum, and the fluorescence decays can be well described by a bi-exponential decay function with time coefficients of ~0.4 ns and ~2 ns. By observation of the change of the transients as a function of the concentration of the ZnPP / THF solution, we assign the fast and slow decay times being due to the intermolecular energy transfer of the aggregated molecules, and the S1→T1 intersystem crossing (ISC), respectively. Inside AAO, the fluorescence of ZnPP was significantly quenched. Changing the different experimental conditions such as the initial ZnPP / THF concentration, the sample immersion time, and the radial size of the AAO nanotubes, we discussed the observed relaxation dynamics. On the other hand, ZnPP molecules bound to Apo-myoglobin in buffer solution have shown sharp and red-shifted spectral feature in comparison with that of ZnPP in free buffer solutions. We studied the dynamics of the ZnPP˙Apo-Mb complex using the technique of time-resolved fluorescence anisotropy.
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47

Cavallaro, Giovanni Ferrante. "Pseudo-dynamic tests and numerical analysis of free from damage Multistorey Steel Buildings with innovative connections." Doctoral thesis, 2019. http://hdl.handle.net/10316/95020.

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One of the most widespread structural systems is represented by Moment Resisting Frames (MRFs). This structural system is made up of frames capable of resisting seismic actions through predominantly flexural tension states. The stiffness and lateral resistance of the system depend on the flexural strength of the members and the type of connection, while the development of the plastic hinges guarantee the dissipation of the seismic input energy. The location of the dissipative zones varies according to the design approach adopted, typically they develop in beams, columns and connections. The most widespread design philosophy is to have strong columns, weak beams and full-strength rigid connections with complete resistance restoration, in this way all the seismic energy tends to be dissipated by the plastic hinges at the ends of the beams and at the base of the columns of the first level. In order to overcome the traditional design approach, the present research work introduces a new type of beam-column connection capable of exhibiting a remarkable rigidity in service conditions (SLE) and able to exhibit a remarkable dissipative capacity when a rare seismic event occurs. The codes currently in force provide that for seismic events characterized by a period of return comparable with the useful life of the construction (frequent or occasional events) the structures remain in the elastic field ensuring that the seismic energy is completely dissipated through viscous damping. Vice versa, the seismic energy must be dissipated through plastic engagement of parts of the Pseudo dynamic tests and numerical analysis of free from damage multistorey steel buildings with innovative connections structure, with wide and stable hysteresis cycles, for rare and very rare seismic events with a return period of about 500 years. The development of the hysteresis involves structural damage that have to be such as not to lead to the collapse of the structure in order to guarantee the protection of the life of those who occupy the building. The prediction of the behaviour of the structure in non-linear field for rare seismic events represents an aspect that only experimental research can describe in depth by developing new analytical models and innovative design philosophies. The execution of quasi-static tests can provide useful information in order to investigate the nonlinear behaviour of the members and the assemblages even if the forces or the displacement histories applied during the tests do not correspond exactly to the actions that occur during a real seismic event. The information obtained through these test procedures is however useful for calibrating analytical models and comparing the behaviour of structural components. The execution of tests on real scale structures is the best way to investigate the global behaviour of a structural system. For a more complete knowledge about the response in the dynamic field, the pseudo-dynamic tests represent a test protocol able to provide information of the structural response of a component or of a structure in a dynamic field through a static test. The main purpose of this work, developed within the FREEDAM research project financed by the European Community, is to develop an innovative beam-column connection. These innovative connections are equipped with an additional damper able to dissipate the energy deriving from destructive seismic events. The FREEDAM beam-column connection, through an appropriate design of the various components, is able to withstand frequent earthquakes and rare events without causing damage to the structural elements.
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48

Sashi, Kumar G. N. "Shape Optimization Using A Meshless Flow Solver And Modern Optimization Techniques." Thesis, 2006. http://hdl.handle.net/2005/430.

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The development of a shape optimization solver using the existing Computational Fluid Dynamics (CFD) codes is taken up as topic of research in this thesis. A shape optimizer was initially developed based on Genetic Algorithm (GA) coupled with a CFD solver in an earlier work. The existing CFD solver is based on Kinetic Flux Vector Splitting and uses least squares discretization. This solver requires a cloud of points and their connectivity set, hence this CFD solver is a meshless solver. The advantage of a meshless solver is utilised in avoiding re-gridding (only connectivity regeneration is required) after each shape change by the shape optimizer. The CFD solver is within the optimization loop, hence evaluation of CFD solver after each shape change is mandatory. Although the earlier shape optimizer developed was found to be robust, but it was taking enoromous amount of time to converge to the optimum solution (details in Appendix). Hence a new evolving method, Ant Colony Optimization (ACO), is implemented to replace GA. A shape optimizer is developed coupling ACO and the meshless CFD solver. To the best of the knowledge of the present author, this is the first time when ACO is implemented for aerodynamic shape optimization problems. Hence, an exhaustive validation has become mandatory. Various test cases such as regeneration problems of (1) subsonic - supersonic nozzle with a shock in quasi - one dimensional flow (2) subsonic - supersonic nozzle in a 2-dimensional flow field (3) NACA 0012 airfoil in 2-dimensional flow and (4) NACA 4412 airfoil in 2-dimensional flow have been successfully demonstrated. A comparative study between GA and ACO at algorithm level is performed using the travelling salesman problem (TSP). A comparative study between the two shape optimizers developed, i.e., GA-CFD and ACO-CFD is carried out using regeneration test case of NACA 4412 airfoil in 2-dimensional flow. GA-CFD performs better in the initial phase of optimization and ACO-CFD performs better in the later stage. We have combined both the approaches to develop a hybrid GA-ACO-CFD solver such that the advantages of both GA-CFD and ACO-CFD are retained with the hybrid method. This hybrid approach has 2 stages, namely, (Stage 1) initial optimum search by GA-CFD (coarse search), the best members from the optimized solution from GA-CFD are segregated to form the input for the fine search by ACO-CFD and (Stage 2) final optimum search by ACO-CFD (fine search). It is observed that this hybrid method performs better than either GA-CFD or ACO- CFD, i.e., hybrid method attains better optimum in less number of CFD calls. This hybrid method is applied to the following test cases: (1) regeneration of subsonic-supersonic nozzle with shock in quasi 1-D flow and (2) regeneration of NACA 4412 airfoil in 2-dimensional flow. Two applications on shape optimization, namely, (1) shape optimization of a body in strongly rotating viscous flow and (2) shape optimization of a body in supersonic flow such that it enhances separation of binary species, have been successfully demonstrated using the hybrid GA-ACO-CFD method. A KFVS based binary diffusion solver was developed and validated for this purpose. This hybrid method is now in a state where industrial shape optimization applications can be handled confidently.
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49

Häckel, Sascha. "Hybride Ansätze basierend auf Dynamic Programming und Ant Colony Optimization zur mehrkriteriellen Optimierung Kürzester-Wege-Probleme in gerichteten Graphen am Beispiel von Angebotsnetzen im Extended Value Chain Management." Master's thesis, 2006. https://monarch.qucosa.de/id/qucosa%3A19381.

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In einer von Vernetzung und Globalisierung geprägten Umwelt wächst der Wettbewerbsdruck auf die Unternehmen am Markt stetig. Die effektive Nutzung der Ressourcen einerseits und die enge Zusammenarbeit mit Lieferanten und Kunden andererseits führen für nicht wenige Unternehmen des industriellen Sektors zu entscheidenden Wettbewerbsvorteilen, die das Fortbestehen jener Unternehmen am Markt sichern. Viele Unternehmen verstehen sich aus diesem Grund als Bestandteil so genannter Supply Chains. Die unternehmensübergreifende Steuerung und Optimierung des Wertschöpfungsprozesses stellt ein charakteristisches Problem des Supply Chain Managements dar und besitzt zur Erzielung von Wettbewerbsvorteilen hohes Potential. Produktionsnetzwerke sind ein wesentlicher Forschungsschwerpunkt der Professur für Produktionswirtschaft und Industriebetriebslehre an der TU Chemnitz. Das Extended Value Chain Management (EVCM) stellt ein kompetenzorientiertes Konzept für die Bildung und zum Betrieb hierarchieloser temporärer regionaler Produktionsnetzwerke im Sinne virtueller Unternehmen dar. Gegenstand dieser Arbeit ist ein diskretes Optimierungsproblem, dass einen mehrstufigen Entscheidungsprozesses unter Berücksichtigung mehrerer Ziele abbildet, der sich bei der Auswahl möglicher Partner in einem Produktionsnetzwerk nach dem Betreiberkonzept des EVCM ergibt. Da mehrere Zielstellungen bestehen, werden grundlegende Methoden der mehrkriteriellen Optimierung und Entscheidung erörtert. Neben der Vorstellung des Problems sollen mehrzielorientierte Ansätze im Sinne einer Pareto-Optimierung auf Basis des Dynamic Programmings als Verfahren zur Bestimmung von Optimallösungen sowie Ant Colony Optimization zur näherungsweisen Lösung vorgestellt werden. Darauf aufbauend werden verschiedene Möglichkeiten der Hybridisierung beider Methoden diskutiert. Die entwickelten Ansätze werden auf ihre Eignung im Rahmen der informationstechnischen Umsetzung des EVCM-Konzepts untersucht und einer Evaluierung unterzogen. Hierzu werden verschiedene Kennzahlen zur Beurteilung der Verfahren entwickelt. Die modellierten Algorithmen und entwickelten Konzepte beschränken sich nicht ausschließlich auf das betrachtete Problem, sondern können leicht auf Probleme mit ähnlichen Eigenschaften übertragen werden. Insbesondere das NP-vollständige mehrkriterielle Kürzeste-Wege-Problem stellt einen Spezialfall des behandelten Optimierungsproblems dar.
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50

Carvalho, Carlos Alberto Santos de. "Jesus um homem para os outros : a salvação como libertação : uma reflexão no contexto da UL 2 do 6º ano de escolaridade." Master's thesis, 2018. http://hdl.handle.net/10400.14/25670.

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No presente texto, partindo da afirmação de que o ser humano é, desde a sua origem, um ser religioso, procura-se fundamentar a existência da disciplina de EMRC, como resposta aos desafios contemporâneos da iliteracia religiosa, da ausência de sentido e do pluralismo. Depois de uma reflexão cuidada sobre a Prática de Ensino Supervisionada, a partir da história do dogma e da Tradição, apresentando Jesus como libertador e inspirado pela Palavra de Deus, procurase traduzir o conceito teológico de salvação como libertação. Deste modo, afirma-se que as aulas de EMRC devem ser humanizadoras, recentrando-se na hermenêutica bíblica e procurando traduzir para uma linguagem contemporânea conceitos teológicos complexos. Conclui-se, por isso, que a salvação que Jesus realiza e oferece é a libertação do ser humano e a concretização plena da sua vocação para ser livre.
The present text, based on the assertion that the human being is, from his origin, a religious being, seeks to justify the existence of the EMRC discipline, in response to the contemporary challenges of religious illiteracy, lack of meaning and pluralism. After a careful reflection on the Supervised Teaching Practice, starting from the history of dogma and Tradition, presenting Jesus as liberator and inspired by the Word of God, we seek to translate the theological concept of salvation as liberation. In this way, it is affirmed that the classes of EMRC must be humanizing, refocusing on biblical hermeneutics and trying to translate complex theological concepts into a contemporary language. It is concluded, therefore, that the salvation that Jesus accomplishes and offers is the liberation of the human being and the full realization of his vocation to be free.
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