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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Arquitetura, historia de vida e infestação por lianas em especies arboreas de florestas semideciduas no municipio de Campinas, SP / Architecture, life history and liana infestation of tree species in semideciduous forests from Campinas, SP

Dias, Arildo de Souza, 1979- 12 August 2018 (has links)
Orientador: Fernando Roberto Martins / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-12T18:43:37Z (GMT). No. of bitstreams: 1 Dias_ArildodeSouza_M.pdf: 671371 bytes, checksum: 783000fd26b32c833785efd804fe2f1d (MD5) Previous issue date: 2009 / Resumo: Lianas possuem um papel chave na dinâmica de ecossistemas florestais, principalmente no que diz respeito aos efeitos diretos exercidos sobre os forófitos, como diminuição da taxa de crescimento e reprodução e aumento da taxa de mortalidade. Nosso objetivo foi responder a três questões principais: Espécies de árvores têm diferentes susceptibilidades à infestação por lianas? Quais características arquiteturais e de história de vida dos forófitos são correlacionadas com a infestação por lianas? Árvores com 51-100% da copa coberta com lianas apresentam diferenças em alometria e desenho mecânico (fator de segurança e esbelteza do caule), comparadas às árvores congenéricas sem infestação da copa? Utilizamos um conjunto de dados previamente coletados sobre infestação da copa por lianas em 10 fragmentos de florestas semedicíduas no município de Campinas, e acrescentamos informações sobre características arquiteturais e de história de vida para 54 espécies arbóreas. Dezoito espécies apresentaram um número de indivíduos infestados que diferiu significativamente do número médio de árvores infestadas no fragmento. Com base nesses resultados classificamos as espécies em três categorias de susceptibilidade à infestação: alta, baixa e variável. No geral, as espécies arbóreas com maior infestação por lianas foram caracterizadas por altura do fuste baixa, grande profundidade da copa, tipo de casca rugosa a profundamente sulcada e fenologia foliar decídua. Em quatro espécies, os coeficientes alométricos entre altura total e diâmetro das árvores com copas infestadas foram significativamente menores que das árvores livres de lianas, com árvores infestadas mais próximas ao limite teórico de tombamento pelo modelo de similaridade elástica. Em média, o fator de segurança (diâmetro crítico para o tombamento) foi menor para as árvores infestadas. O fator de segurança e a esbelteza do caule estiveram negativamente relacionados tanto em árvores infestadas, quanto em árvores livres de lianas, mas árvores com lianas apresentaram maior valor do coeficiente do que árvores sem lianas. Espécies diferentes têm diferentes susceptibilidades a lianas. A combinação de características arquiteturais e de história de vida em forma de síndromes, como altura do fuste, profundidade da copa, fenologia foliar e tipo de casca, muito mais que cada caráter individual, influi na susceptibilidade à infestação por lianas. O fato de árvores infestadas terem menor estabilidade em relação ao limite teórico de tombamento elástico poderia implicar em maior taxa de mortalidade em relação a árvores livres de lianas. / Abstract: Lianas have a key role in forest dynamics and processes in the ecosystem, and may reduce host tree growth rates, fecundity and survival. We address three main questions: Do tree species differ in their susceptibility to lianas? What host tree architectural and life history traits are correlated with the liana infestation? Tree with 51-100% of crown infestation shows difference in alometry and mechanical design (safety factor and slenderness) in relation to trees without lianas? We utilize a data set on liana infestation in ten semideciduous forest fragments of Campinas city, and we added tree architectural and life history traits for 54 tree species. Eighteen species had a higher or lower proportion of liana-infested individuals than the mean number of infested trees in the forest. The tree species was classified in three categories about to susceptibility: high, low and variable. In general, tree species with higher liana infestation were characterized by a low first branch height, high depth crown, bark type slightly rough to strongly fissured and deciduous leaves. In four species the allometric coefficient for height-diameter relations in liana-infested trees was significantly lower than liana-free trees, and liana-infested trees was more close to minimum diameter required to prevent elastic buckling in wooded columns. The safety factor and slenderness was negatively correlated for liana-infested trees and liana-free trees. However, liana-infested trees had higher slope for relationship between these two variables (safety factor and slenderness). Our results pointed out that the combination of tree architectural and life history traits as free bole height, depth crown, foliar phenology and bark type, more than each isolated feature, are important factors determining to liana infestation of tree species analyzed. We suggest that the lower mechanical stability of liana-infested trees could be a cause to higher mortality rates in those trees in comparison to trees without lianas. / Mestrado / Mestre em Biologia Vegetal
12

Considerações sobre a aplicação do método dos elementos finitos à análise de estabilidade de taludes / Considerations on application of finite element method to slope stability analysis

Paulo Gustavo Cavalcante Lins 17 April 1996 (has links)
O presente trabalho apresenta um estudo sobre o cálculo dos fatores de segurança de taludes utilizando o campo de tensões obtido pelo método dos elementos finitos. São discutidas diferentes definições para o fator de segurança global do maciço. Considerações sobre a definição do fator de segurança, em termos de deslocamentos, também são traçadas. Foi desenvolvido um pós-processador gráfico, para a visualização dos resultados das análises por elementos finitos. Estudos de um talude estável e de um caso de ruptura foram realizados. Os fatores de segurança obtidos mostraram-se coerentes com os resultados dos métodos de equilíbrio limite convencionais. No caso do talude estável, a influência da deformabilidade relativa do maciço foi analisada. / The present work shows a study about computation of slope stability safety factors using stress fields generated by finite element method analysis. Differents definitions of the global safety factor are discussed. Considerations about the definition of the safety factor in terms of nodal displacements are addressed too. A graphical software for visualizing the results of finite element method analysis was developed for this study. Studys of a stable slope and a failure case are performed. Safety factors values were both consistent with results of conventional limit equilibrium methods. Influence of relative deformability is analyzed in the stable case.
13

Zajištění hlubokého zářezu v sesuvné oblasti / Securing of Deep Cut in Slide Area

Pargač, Martin January 2013 (has links)
The thesis called Securing of Deep Cut in Slide Area focuses on the basic analysis of the problems connected to landslides and securing of the slopes. It also presents a solution of a certain problem, where the slope stability, potencional landslide launchers and subsequent remediaton are discussed.
14

Ojnice plynového vidlicového šestnáctiválce / Connecting rod of gas V-sixteen engine

Laštovica, Karel January 2011 (has links)
This diploma thesis deals with a design of a stationary engine connecting rod, its stress analysis and its safety factors. The thesis is divided into several parts. At the beginning there is a short research of connecting rods construction and a description of the engine. Then the main dimensions of a piston group and a connecting rod are defined and its 3D model is created. Next, the calculations of forces acting on the connecting rod in the crankshaft mechanism, are carried out. The following part deals with a stress analysis of the model created by MPK. From the obtained stress results, the safety factor at fatigue limit in chosen places of the connecting rod is calculated. In the conclusion, the results of the stress analysis and set safety factor level, are recapitulated.
15

Pětiválcový řadový vznětový motor / Five-cylinder in-line diesel engine

Kujawa, Pawel January 2011 (has links)
The primary objective of this thesis was to design a crankshaft according to given parameters. In this case the thesis also contains the balancing of inertia forces and its moments, modal analysis and calculation of torsion vibrations. The last chapter includes a calculation of the safety factor by using a Finite Element Method.
16

GEOTECHNICAL INFRASTRUCTURE ASSET MANAGEMENT FOCUSING ON PERFORMANCE DETERIORATION PROCESS OF GROUND ANCHORS / グラウンドアンカーの性能低下過程に着目した地盤構造物アセットマネジメント

Taweephong Suksawat 24 September 2014 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第18574号 / 工博第3935号 / 新制||工||1605(附属図書館) / 31474 / 京都大学大学院工学研究科都市社会工学専攻 / (主査)教授 大津 宏康, 教授 河野 広隆, 教授 清野 純史 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM
17

Additive Design Process for Critical Structures: Attempt study

Kassir, Tomas, Prathan, Kanthee January 2022 (has links)
There is a gap in scientific knowledge regarding designing functional parts that may not fail, and this project came to define these parts as critical structures. The proposed design process is called the Additive Design Process for Critical Structure, which synthesizes required activities found in the literature review necessary to produce theoretically safe design structures. Although this proposed design process does not meet the requirements of a safe design as intended and must be further studied before the proposed design process can be adapted. The project’s ambition was to integrate the design’s safety with value components, referred to as elements/activities/tools/processes that could contribute to innovation and value creation, to exploit the advantages of additive manufacturing in the design process. The research conducted in this project adapted and applied Design Research Methodology (DRM), written by Blessing & Chakrabarti (2009). Two main research questions were studied that lay a foundation for this thesis, presented below. The project combined quantitative and qualitative research methods to generate the necessary knowledge and then apply/test the derived knowledge to answer these research questions. RQ1: What activities can this project identify to synthesize an additive design process in constructing critical structures for Additive Manufacturing (AM)? RQ2: What are the possible value components to include in the additive design process that would contribute to innovation concerning lead time, weight, and mass customization? The results show that the proposed design process, Additive Design Process for Critical Structured, did not meet the theoretical safe design. However, the findings still suggest that the required activities to achieve a safe design are by introducing defined and explicit protective measurements in the design process. The protective measurement parameters identified in this project were safety factors and Finite Element Analysis (FEA); the question of why the design process does not meet the requirements of producing a theoretical safe design is unknown today and needs further study. Concerning the second RQ, the results showed that Generative Design (GD) was this project's most innovative value component. Adapting GD contributed to shortening the product development time, liberating the design engineer to explore a bolder concept, reducing weight, and allowing the design engineers to generate mass customization. Keywords: Design for Additive Manufacturing, Design Process, Generative Design, Method, Critical Structures, Safety factor.
18

Enabling safety-informed design decision making through simulation, reasoning and analysis

Jensen, David Charles 30 April 2012 (has links)
While many organizations claim to "put safety first," safety is rarely considered early in the design process when system-level architectural decisions are made. Instead, system design follows an abstraction-to-detail process to first meet functional and then performance requirements. Following this process, safety assurance occurs in the later stages of design through a rigorous expert review process. The significant cost of safety-based redesign and the growing complexity of engineered systems motivates a need for early design-stage fault analysis. This research presents a novel method of including safety into the model-based design and analysis of complex systems using low-fidelity behavior simulations. Specifically, this research demonstrates the adaption of the functional design process to explicitly include the system property of safety in the system representation. Next, early design fault analysis is extended to connect component failure behavior to system-level hazards. Finally, this research develops three methods of results clustering to provide different evaluation metrics of the system design. In summary, this research demonstrates a framework for incorporating safety into early design decision making. This research addresses safety and failure in the design of complex systems incorporating diverse technology domains as found in energy, transportation, and aerospace systems. / Graduation date: 2012
19

Dealing with uncertainty

Clausen Mork, Jonas January 2012 (has links)
Uncertainty is, it seems, more or less constantly present in our lives. Even so, grasping the concept philosophically is far from trivial. In this doctoral thesis, uncertainty and its conceptual companion information are studied. Axiomatic analyses are provided and numerical measures suggested. In addition to these basic conceptual analyses, the widespread practice of so-called safety factor use in societal regulation is analyzed along with the interplay between science and policy in European regulation of chemicals and construction. / QC 20120202
20

A chemistry-inspired middleware for flexible execution of service based applications

Wang, Chen 28 May 2013 (has links) (PDF)
With the advent of cloud computing and Software-as-a-Service, Service-Based Application (SBA) represents a new paradigm to build rapid, low-cost, interoperable and evolvable distributed applications. A new application is created by defining a workflow that coordinates a set of third-party Web services accessible over the Internet. In such distributed and loose coupling environment, the execution of SBA requires a high degree of flexibility. For example, suitable constituent services can be selected and integrated at runtime based on their Quality of Service (QoS); furthermore, the composition of service is required to be dynamically modified in response to unexpected runtime failures. In this context, the main objective of this dissertation is to design, to develop and to evaluate a service middleware for flexible execution of SBA by using chemical programming model. Using chemical metaphor, the service-based systems are modeled as distributed, selforganized and self-adaptive biochemical systems. Service discovery, selection, coordination and adaptation are expressed as a series of pervasive chemical reactions in the middleware, which are performed in a distributed, concurrent and autonomous way. Additionally, on the way to build flexible service based systems, we do not restrict our research only in investigating chemical-based solutions. In this context, the second objective of this thesis is to find out generic solutions, such as models and algorithms, to respond to some of the most challenging problems in flexible execution of SBAs. I have proposed a two-phase online prediction approach that is able to accurately make decisions to proactively execute adaptation plan before the failures actually occur.

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