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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.
121

Elliptical Hollow Section T and X Connections

Haque, Tarana Haque 08 December 2011 (has links)
Elliptical hollow sections (EHS) are the newest steel shape to emerge in the industry, but appropriate design guidance is lacking, being completely absent from Canadian codes and guidelines. Geometric property and compressive resistance tables were established to be potentially added to the Canadian guides. The equivalent RHS method, originally proposed by Zhao and Packer in 2009, was simplified and modified to validate its use for the design of EHS columns and beams. An experimental programme was developed to investigate the behaviour of EHS-to-EHS welded connections. Twelve T and X connection tests were performed to study the effect of connection angle, orientation type and loading. Two methods were developed to predict connection capacities and failure modes: the equivalent CHS and the equivalent RHS approaches. Both methods proved to be conservative on average, but the equivalent RHS approach proved to be more successful at capturing the actual failure mode of EHS-to-EHS connections.
122

The Power of Social Connections: Feelings of Connectedness Result in Sharing Goals, Emotions, and Intergroup Empathy

Cwir, David January 2011 (has links)
The purpose of the following research was to test the prediction that a sense of social connectedness to a stranger would result in the tendency to share psychological states with him/her. An overview of the literature on state sharing and the psychological merging between other and self is described in Chapter 1. The first test of my prediction is provided in Chapter 2 where I demonstrate that participants who are led to feel socially connected to a confederate--by sharing idiosyncratic preferences in common with her--resulted in the propensity to take on her goals. In Chapter 3, participants who felt connected to a confederate who was asked to complete a stressful speech task experienced more stress themselves. This effect occurred in part through a sense of felt “oneness” with the confederate. Chapter 4 extended these findings by showing that socially connected participants tended to experience secondary appraisal emotions in line with the confederate’s appraisal of the stressful speech task and this occurred through a sense of felt oneness with the confederate. In Chapter 5, participants who felt connected to an outgroup member tended to experience greater empathy for another outgroup member who experienced discrimination. The implications for social interaction in general and for intergroup relations in particular are discussed in Chapter 6.
123

Adolescent Perceptions and Attitudes towards Invasive Species and Nature

Creelman, Kyle 26 September 2011 (has links)
Invasive species are one of many important environmental issues facing Canadians today. A great deal of research has explored both the scientific and social aspects of invasive species. However, the cumulative research has not yet thoroughly explored people’s thoughts and feelings about, or perceptions of, invasive species and the influence these may have on management of, or policy decisions regarding, invasive species. This thesis research project was designed to assess the attitudes and perceptions that high school students have towards invasive species and to determine to what extent learning about invasive species alters their connection with nature. The study group was comprised of students from four Grade 11 Environmental Science classes from three high schools within the city of Guelph, Ontario. The students received regular classroom instruction from their teachers covering the course content, including invasive species. Students also made weekly visits to a local nature centre, providing them with hands-on learning experiences related to the course content. Students responded to an 80-question survey that assessed their knowledge of local invasive species and attitudes towards them as well as students’ connection to nature. Their connection to nature was assessed using a modified version of the Connectedness to Nature Scale (Mayer & Frantz, 2004). The surveys were administered by the classroom teachers in October, 2010, prior to the presentation of instructional material covering invasive species and then again in December, 2010 when the presentation of instructional material concerning invasive species was complete. The results showed that the students’ knowledge of invasive species upon entering the course was quite low and each of the classes witnessed a significant increase in knowledge. The survey results did not reveal any change to the students’ connection to nature; however, they did reveal three underlying themes in students’ attitudes towards invasive species: a concern about invasive species as a threat or problem; feelings of acceptance towards invasive species; and feelings of anxiety about invasive species. These attitudes remained relatively unchanged after the course.
124

Innovative Shear Connections for the Accelerated Construction of Composite Bridges

Chen, Yu-Ta January 2013 (has links)
Accelerated bridge construction methods are being progressively used to construct and replace bridges in North America. Unlike traditional bridge construction methods, accelerated bridge construction methods allow bridges to be built in a shortened period of time on the construction site. These methods reduce the road closure time and the traffic disruption that are associated with bridge construction. One of these methods is carried out by prefabricating the bridge elements offsite and then assembling them onsite in a time-efficient way to build the bridge. This construction method can be used to build steel-precast composite bridges, where steel plate girders are connected to full-depth precast concrete deck panels. For the expeditious construction of composite bridges, a proper shear connection detail is needed to develop composite action between the steel plate girders and the precast concrete deck panels. This research project investigated two types of shear connection that would accelerate the construction of steel-precast composite bridges. First, finite element analysis was used to study the behaviour of composite bridge girders with panel end connections. The girders were analyzed for their load-displacement behaviour, cross-sectional stress and strain profile, and connection force distributions. Secondly, experimental push tests were conducted to study the load-slip behaviour of bolted connections. The effects of steel-concrete interface condition, bolt diameter and bolt tension on the shear capacity of bolted connections were analyzed. Based on the finite element analysis results, it is concluded that the panel end connected girder exhibited strong composite action at service and ultimate load. The level of composite action decreased slightly when the panel end connection stiffness was reduced by a factor of ten. Based on the experimental results, it is concluded that the total shear capacity of the bolted connection is the sum of the friction resistance and the bolt dowel action resistance. The friction resistance of the connection depends on the interface condition and the bolt clamping force. An analytical model that can predict the ultimate shear capacity of bolted connections has been developed and recommended. The proposed model is shown to give reliable predictions of the experimental results. It should be noted that bolted connections exhibit good structural redundancy because the bolt fracture failures do not happen simultaneously.
125

An optimization approach for the cascade vulnerability problem

Servín Meneses, Christian, January 2009 (has links)
Thesis (M.S.)--University of Texas at El Paso, 2009. / Title from title screen. Vita. CD-ROM. Includes bibliographical references. Also available online.
126

The Texas Library Connection network : usage by school library media specialists related to the stages of concern /

Haynes, Dorothy Elizabeth, January 1999 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 1999. / Vita. Includes bibliographical references (leaves 128-132). Available also in a digital version from Dissertation Abstracts.
127

Garden Earth and church gardens: creation, food, and ecological ethics

Grenfell-Lee, Tallessyn Zawn 19 May 2016 (has links)
In order to address the full magnitude of the ecological crisis, communities need points of contact that provide enjoyment, build community, and foster "nature connection." The ability of the local food movement to provide these points of contact has fueled its rapid expansion in the last decade; however, no study to date has examined the impact of direct involvement in the movement on the ecological ethics of local congregations. This study assessed the impact of a communal vegetable garden project on the ecological ethics of an urban and a suburban United Methodist congregation in the Boston area. The study used a participatory action ethnographic model as well as an Ecological Ethics Index scale to assess overall impacts as well as impacts in the areas of ecological spirituality, community, discipleship, and justice. The study found impacts in all four areas, particularly within the suburban congregation, which integrated the project into the central identity and ministries of the church. The urban church had already integrated other food justice ministries into its central identity and ministry; the data also showed impacts in the urban church context, particularly among the project participants. The main findings of the study revealed the influential role of supportive communities, and particularly of elder mentors, in fostering nature connection experiences among the participants. The church-based locations of the gardens, as well as the hands-on, participatory nature of the projects, increased Earth-centered spiritual awareness and practices as well as pro-environmental discipleship behaviors. The visual impact of the gardens in a church context increased awareness of issues related to food justice. The gardens functioned as a means of grace that connected the participants and the wider congregations to the land near their church buildings in new ways; the gardens provided a connection to concepts of the Divine in the Creation as well as enjoyable opportunities to share the harvest among the community and with hungry communities. In these ways, the gardens connected the congregations to the Wesleyan ideas of grace and inspired new forms of Wesleyan responsibility for social and ecological transformation.
128

Redução de harmônicos de corrente em retificadores de múltiplos pulsos: generalização das conexões diferenciais

Gonçalves, Vinícius Assad [UNESP] 02 May 2006 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:29:41Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-05-02Bitstream added on 2014-06-13T19:38:59Z : No. of bitstreams: 1 goncalves_va_me_ilha.pdf: 2872091 bytes, checksum: 81ed1113b369e242f34f8801629c4f82 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Este trabalho apresenta o estudo comparativo de diversas topologias de conversores CA-CC trifásicos de múltiplos pulsos, baseados nas conexões especiais de transformadores, principalmente nas conexões diferenciais de autotransformadores. Esta técnica de retificação trifásica apresenta as vantagens do baixo conteúdo harmônico de corrente na rede e da reduzida potência aparente processada pelo núcleo dos autotransformadores. As conexões Y-diferenciais e Delta-diferenciais de 12 e de 18 pulsos são generalizadas através de expressões algébricas únicas que descreve toda a família dos conversores desta natureza, para quaisquer valores de tensão de entrada e de saída. Dentre estes conversores, a topologia Delta-diferencial de 18 pulsos é escolhida para estudo detalhado da distorção harmônica de corrente na rede de alimentação, além do projeto e da implementação de dois protótipos, um de 1 kW e outro de 6 kW. As saídas das estruturas retificadoras são ligadas em paralelo com o uso de transformadores de interfase que absorvem as diferenças instantâneas de tensão entre as saídas dos retificadores, possibilitando assim a operação do conversor com carga única. Desta forma, a proposta principal deste trabalho é gerar múltiplos pulsos de tensão na carga e, como conseqüência, obter conversores que apresentem múltiplos pulsos na forma de onda da corrente na rede de alimentação. Os resultados experimentais dos protótipos implementados são então comparados com a análise matemática desenvolvida e com os resultados de simulação. / This work presents a comparative study of several multiple pulse AC-DC three-phase converter topologies, based on the special connections of transformers and differential connections of autotransformers. This three-phase technique presents the advantages of low harmonic current in the mains and the reduced power rated to the magnetic system of the autotransformer. The 12 and 18-pulse differential Y-connections and differential delta-connections are generalized by one algebraic expression. This expression describes the family of these converters for any value of input and output voltages. Among these converters, the 18-pulse delta-connected topology is chosen for a detailed study on the line current harmonic distortion, and two prototypes are designed and experimented on, one with 1 kW and another one with 6 kW. The outputs of the rectifiers structures are connected in parallel with the use of the interphase transformers, reducing this way, the current efforts in each rectifier and making possible the connection from DC outputs of the three rectifiers. In this way, the proposal aim of this work is to generate a multipulse voltage on the load, so that, it has as important result, the multipulse current, with reduced harmonics, in the mains. The experimental results of the prototypes are compared to the simulated circuits and the analytical results.
129

Processo otimizado para a produção de módulos educacionais = um estudo de caso do Projeto Conexão do Saber / Optimized process for educational modules development : a case study of the Project Conexão do Saber

Inocêncio, Ana Carolina Gondim 18 August 2018 (has links)
Orientador: Leonardo de Souza Mendes / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-18T03:06:21Z (GMT). No. of bitstreams: 1 Inocencio_AnaCarolinaGondim_D.pdf: 14668129 bytes, checksum: 7f20b57d3c28bcaf1c0a0f9a82a90ca6 (MD5) Previous issue date: 2011 / Resumo: A inserção do computador na área da educação tem provocado grandes discussões sobre a vigente concepção de ensino e aprendizagem. A abundância de programas educacionais e os diversos tipos de uso do computador indicam que esta tecnologia pode ser de grande utilidade nos processos de ensino e aprendizagem. Um importante projeto onde se estuda o impacto do uso de módulos educacionais em um programa de ensino mediado por computador é o projeto Conexão do Saber, desenvolvido pelo Laboratório de Redes de Comunicações da Faculdade de Engenharia Elétrica e Computação da UNICAMP, por meio de parcerias com laboratórios de pesquisa do Brasil e do exterior e junto com equipes educacionais e pedagógicas de oito municípios brasileiros. Este trabalho discute o projeto Conexão do Saber no que tange os processos de desenvolvimento dos módulos educacionais, propondo um processo otimizado para o seu desenvolvimento. O processo proposto é baseado em padrões de engenharia de software e tem dois objetivos principais: (i) diminuir o tempo necessário para a produção de um módulo educacional; (ii) promover o envolvimento profundo dos professores neste processo de produção. Os resultados obtidos durante o acompanhamento da produção dos módulos mostram que foi possível reduzir o tempo de produção sem comprometer qualidade. Além disso, o processo possibilitou que o professor defina os requisitos dos módulos produzidos e acompanhe todo o seu desenvolvimento, participando ativamente da sua produção / Abstract: The insertion of computer in education area has caused a true revolution in the current conception of learning and teaching. The great amount of educational softwares and the different purposes of computer usage indicate that this technology may be very useful in the teaching-learning process. An important research project that studies the impact of educational module application in a computer-mediated education program is the project named Conexão do Saber. It is developed by the Laboratory of Communication Networks at the School of Electrical and Computer Engineering of the University of Campinas, through partnerships with Brazilian and other countries research laboratories, besides education departments of eight Brazilian cities. This work proposes a simplified process to develop educational modules in the project named Conexão do Saber. The proposed process is based on software engineering patterns. It has two main objectives: (i) reduce the development time of an educational module; (ii) promote a strong teachers' involvement in educational modules development. The results obtained during the development of modules showed that it was possible to reduce the development time. Moreover, the proposed process enables teachers to define the module requirements and to participate in the module development process / Doutorado / Telecomunicações e Telemática / Doutor em Engenharia Elétrica
130

Graphical Web Interface for OpenModelica Platform

Baloch, Adeel January 2013 (has links)
“OPENMODELICA is an open-source Modelica-based modeling and simulation environment intended for industrial and academic usage. Its long-term development is supported by a non-profit organization – the Open Source Modelica Consortium (OSMC).” OpenModelica aims to provide an enhanced, Open Source Modelica modeling and simulation environment and this thesis is an addition in this direction.  The purpose of this thesis is to create a web based graphical connection editor. There are other open-source connection editors available, but these editors were desktop applications. There is one web based editor but it is a textual editor. Desktop applications need installation and space on the local system. OMWeb connection editor is the first web based graphical connection editor that runs on a web browser. It’s a web platform for OpenModelica and provides the environment for modeling and simulation in the Modelica Modeling Language. The OMWeb connection editor can run on any system without the need for an OpenModelica installation. If a system is connected to the internet, and contains a web browser, it can run the OMWeb connection editor. The OMWeb connection editor uses Java Runtime Environment to run an applet in the browser. The user can create models graphically; but they can also be viewed in the textual format. The user can simulate and plot his models. The plot file generated for the model can be downloaded from the server.  The OMWeb Connection Editor uses Servlet to handle requests from the client. The servlet is responsible for the communication with OpenModelica Compiler. It also gets the results from OMC and sends them back to the client. In our case the browser is the client.

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