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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

GFRP-Reinforced Concrete Guideway Beams for Monorail Applications

Wootton, NIKOLAUS 03 February 2014 (has links)
Increased demand for reliable public transit is motivating new and innovative transportation solutions. Monorail trains are quickly being established as transportation solutions for dense urban areas, due to their unobtrusive infrastructure. To obtain maximum value from investments made, the infrastructure is required to last longer than typical reinforced concrete. This thesis will explore the use of glass-fibre reinforced polymer (GFRP) bars as reinforcement in concrete guideway beams as a means of avoiding the deterioration problems that plague steel-reinforced concrete. This thesis includes a two part investigation: a full-scale field application of a GFRP-reinforced concrete guideway beam (690 mm x 1,500 mm x 11,600 mm), compared to a typical steel-reinforced beam (both installed on a 1.86 km long monorail test track); and a laboratory study of a scaled-down version of the GFRP-reinforced beam to better predict behaviour beyond typical service load levels. A total of 450 test passes of a two-car monorail train were observed over the two instrumented beams on the track. These passes were performed at vehicle loads ranging from fully unloaded for the first testing phase, up to the maximum allowable design service load. At each stage of testing, vehicle speeds ranged from as low as 5 km/h to as high as 90 km/h, allowing for the dynamic behaviour of the guideway to be observed and quantified. Deflections, strains, and cracks were recorded and compared with code/guideline limitations as well as to numerical predictions to determine which design tools were most effective and could predict behaviour accurately. In the laboratory, the half-scale GFRP-reinforced beam was tested statically to failure, and the behaviour was compared to the same modelling tools used in the field study. Based on the testing performed, the GFRP-reinforced concrete beams performed satisfactorily and met all serviceability requirements, but did not perform as well as the steel-reinforced beam (as a result of the reduced stiffness of GFRP). The use of non-prestressed GFRP-reinforced beams should be limited to applications where spans are of comparable length to the field study. To maintain satisfactory performance, guideway spans significantly longer will need to continue to be design as prestressed beams. / Thesis (Master, Civil Engineering) -- Queen's University, 2014-01-31 15:15:31.307
2

Exploring the Relationship between Design and Outdoor Thermal Comfort in Hot and Dry Climate

January 2019 (has links)
abstract: Moderate physical activity, such as walking and biking, positively affects physical and mental health. Outdoor thermal comfort is an important prerequisite for incentivizing an active lifestyle. Thus, extreme heat poses significant challenges for people who are outdoors by choice or necessity. The type and qualities of built infrastructure determine the intensity and duration of individual exposure to heat. As cities globally are shifting priorities towards non-motorized and public transit travel, more residents are expected to experience the city on their feet. Thus, physical conditions as well as psychological perception of the environment that affect thermal comfort will become paramount. Phoenix, Arizona, is used as a case study to examine the effectiveness of current public transit and street infrastructure to reduce heat exposure and affect the thermal comfort of walkers and public transit users. The City of Phoenix has committed to public transit improvements in the Transportation 2050 plan and has recently adopted a Complete Streets Policy. Proposed changes include mobility improvements and creating a safe and comfortable environment for non-motorized road participants. To understand what kind of improvements would benefit thermal comfort the most, it is necessary to understand heat exposure at finer spatial scales, explore whether current bus shelter designs are adequate in mitigating heat-health effects, and comprehensively assess the impact of design on physical, psychological and behavioral aspects of thermal comfort. A study conducted at bus stops in one Phoenix neighborhood examined grey and green infrastructure types preferred for cooling and found relationships between perception of pleasantness and thermal sensation votes. Walking interviews conducted in another neighborhood event examined the applicability of a framework for walking behavior under the stress of heat, and how differences between the streets affected perceptions of the walkers. The interviews revealed that many of the structural themes from the framework of walking behavior were applicable, however, participants assessed the majority of the elements in their walk from a heat mitigation perspective. Finally, guiding questions for walkability in hot and arid climates were developed based on the literature review and results from the empirical studies. This dissertation contributes to filling the gap between walkability and outdoor thermal comfort, and presents methodology and findings that can be useful to address walkability and outdoor thermal comfort in the world’s hot cities as well as those in temperate climates that may face similar climate challenges in the future as the planet warms. / Dissertation/Thesis / Doctoral Dissertation Sustainability 2019
3

Political and Economic Reasons for Energy Cooperation between the EU and Russia

Evgrafova, Elena January 2014 (has links)
In this paper I investigate the energy cooperation between the EU and Russia from the political and economic points of view. The relevance of the issue is due to the growing role of energy sector, the need for security of energy supply and demand and for political and economic balance of power in the region, and closer economic integration. Two theoretical approaches, geopolitical and bureaucratic, guiding the research, explain the behavior of protagonists. To better understand the present level of cooperation I analyze the background and dynamics of EU - Russia energy trade relations. As a case study, I investigate the Nord Stream project as an example of successful cooperation of Germany as an EU member state and Russia in this field. I discuss challenges for the healthy mutual partnership in the energy sector, namely, high politicization of the issue, monopolization of Russian energy sector and low sustainability of Russian economic development, and mistrust between the protagonists. I attempt to identify possible policy changes aimed to improve this cooperation and achieve fruitful partnership, security and stability. Key words: Russia, EU, energy, cooperation, Realpolitik, international relations, oil, gas, energy dialogue, ECT, security, balance of power, geopolitics, interest groups,...

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