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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

Application of Phase Change Materials for Building Energy Retrofits in a Hot Arid Climate

January 2020 (has links)
abstract: In 2018, building energy use accounted for over 40% of total primary energy consumption in the United States; moreover, buildings account for ~40% of national CO2 emissions. One method for curbing energy use in buildings is to apply Demand Side Management (DSM) strategies, which focus on reducing the energy demand through various technological and operational approaches in different building sectors. This PhD research examines the integration of DSM strategies in existing residential and commercial buildings in the Phoenix, Arizona metropolitan area, a hot-arid climate. The author proposes three different case studies to evaluate the effectiveness of one DSM strategy in buildings, namely the integration of Phase Change Materials (PCMs). PCMs store energy in the freezing process and use that stored energy in the melting process to reduce the energy demand. The goal of these case studies is to analyze the potential of each strategy to reduce peak load and overall energy consumption in existing buildings. First, this dissertation discusses the efficacy of coupling PCMs with precooling strategies in residential buildings to reduce peak demand. The author took a case study approach and simulated two precooling strategies, with and without PCM integration, in two sample single-family homes to assess the impact of the DSM strategies (i.e., precooling and PCM integration) on load shifting and load shedding in each home. Second, this research addresses the feasibility of using PCMs as sensible and latent heat storage in commercial buildings. The author documents the process of choosing buildings for PCM installation, as well as the selection of PCMs for retrofitting purposes. Commercial building case studies compare experimental and simulation results, focusing on the impact of the PCMs on reducing the total annual energy demand and energy cost. Finally, this research proposes a novel process for selecting PCMs as energy efficiency measures for building retrofits. This process facilitates the selection of a building and PCM that are complementary. Implementation of this process has not yet been tested; however, the process was developed based on experimental and simulation results from prior studies, and it would alleviate many of the PCM performance issues documented in those studies. / Dissertation/Thesis / Doctoral Dissertation Civil, Environmental and Sustainable Engineering 2020
12

Solid oxide membrane electrolysis of metal oxides for advanced energy applications

Yan, Haoxuan 30 August 2023 (has links)
This thesis presents an exploration of Solid Oxide Membrane (SOM) electrolysis as a solution to the imminent challenge of transitioning from fossil fuel dependence towards sustainable, low-carbon energy technologies. Two key applications are explored: the production of solar-grade silicon for photovoltaic cells and the recycling of iron as an electrofuel. Solid Oxide Membrane (SOM) based electrolysis process is a promising technology that has been demonstrated to successfully produce many energy-intensive metals directly from their oxides in an efficient, economical and environmentally sound way. First, the production of solar-grade silicon from silica via a single-step SOM electrolysis process (Si-SOM) is demonstrated. During the Si-SOM electrolysis process, an yttria-stabilized zirconia (YSZ) tube was employed to separate pre-engineered molten flux with dissolved silica from the anode assembly. When the applied DC potential between the cathode and the anode exceeds the dissociation potential of silica, silicon is reduced at the cathode, while oxygen ions migrate through the YSZ membrane and are oxidized at the anode. The Si-SOM electrolytic cell design and process parameters are optimized to enable high-purity silicon deposition on the cathode and ensure stable and efficient Si-SOM electrolysis. Electrochemical characterization and modeling of the Si-SOM electrolysis are also presented with detailed microstructural analysis of the silicon deposits. In parallel, this thesis demonstrates an innovative method of reducing the iron oxide to iron via a molten salt-free SOM electrolysis (Fe-SOM). Iron oxide and liquid silver as the reducing medium are contained in a one-end closed YSZ membrane. The soluble oxygen is pumped out of liquid silver with an applied potential between the cathode and the anode to create a reducing condition that is sufficient to reduce the iron oxide. The Fe-SOM electrolytic cell design and process parameters are optimized to enable high-efficiency and stable electrolysis of iron oxide. Electrochemical characterization of the Fe-SOM electrolysis is also presented with detailed microstructural analysis of the iron deposits.
13

The Creation of Sustainable Development: What it means to CFOs in New Zealand

Dimitrov, Dara K. January 2009 (has links)
Abstract currently unavailable
14

Towards collaborative planning and management of natural protected areas : a case study in the Formosan Landlocked Salmon Wildlife Refuge, Taiwan

Lee, Kuang-Chung January 2001 (has links)
No description available.
15

Electrochromic Glass

Lagunas, Armando 11 May 2016 (has links)
Sustainable Built Environments Senior Capstone Project / Electrochromic glass is a type of smart glass, a new technology that has potential to reduce the amount of sunlight entering a building by changing its physical properties. The purpose of this study is to understand the properties of electrochromic glass and determine if it is a viable alternative to conventional single pane and double pane glass in the Tucson area. Using research and statistics from smart glass production companies, a comparative analysis will be done using the building simulation software Energy-10. It was found that when compared to single pane glass, double pane glass had a decrease of 7.21% in energy cost and electrochromic glass had a decrease of 9.81%. For the used building model, this meant a return investment in 30 and a half years. While electrochromic glass is a new clean method of energy usage reduction, it currently cannot return the consumers initial investment within a desirable time span.
16

Social ecological food systems| Sustainability lessons from Maine dairy networks

McGuire, Julia Bayer 13 December 2016 (has links)
<p> Milk production has played an integral role in the culture, landscape, and economy of Maine's agriculture. Maine dairy farmers have faced numerous sustainability challenges to economic, environmental, and social aspects of their industry. Like many other complex social ecological systems, the Maine dairy industry faces a gap between scientific knowledge and actionable management or policy. A cultural dichotomy exists between conventional and organic farming. Shifting the focus from this binary, metrics such as social capital may play a key role in solving sustainability issues. Difficulties arise in the governance of complex social ecological systems when the scales of assessment, management, and policy do not match principal challenges. Despite efforts by many, Maine dairy challenges may be fueled by a state political system that is restricted by term limits and short legislative sessions. Piecemeal policy-making leads to assessment and policy outcomes that do not take the complexities of the system into consideration.</p><p> In the case of the Maine dairy industry, using mental modeling and social network analysis: 1) we seek to explore a method that may improve understanding in cases of disintegration between sustainability policy and action; 2) we test whether social capital, measured using Maine dairy farmers' information networks, spans perceived boundaries between conventional and organic management and between different farm sizes, and; 3) we investigate the scale problemscape for long-term success of the Maine dairy industry.</p><p> We found no significant difference in the importance of the economic, environmental, or social factors that dairy farmers considered to be the most challenging to industry sustainability. Social capital, rather than farm management practice or size, is a critical variable for better understanding industry sustainability. We found gaps between the current industry policy structure and the management and assessment scales required to address sustainability challenges. The barriers to effective long-term management, assessment, and policy are numerous for the Maine dairy industry. Our findings suggest that solutions concentrating on only one sustainability factor are unlikely to work in the longterm. Solutions may lie in a more holistic evaluation process, and inclusion of social capital and scale assessments to effectively link science and policy.</p>
17

Essays on Sustainable Development and Human Capital

Anttila-Hughes, Jesse Keith January 2012 (has links)
Sustainable development is often taken to mean development that improves human well being subject to natural constraints over time, but in practice quantifying sustainability outcomes is often difficult. In this dissertation I seek to better elucidate the relationship between sustainable development and its natural constraints by focusing on human capital outcomes, which I argue provide one of our best summary statistics for "human well being" in general. Whether the constraints are imposed by natural systems (Chapters 2 and 3) or human ones (Chapter 4) I find strong evidence to suggest that attempts to pursue sustainable economic development must deal with nuanced and often conflicting interactions between the human capital invesment and accumulation process and its fundamental constraints.
18

Essays on Sustainable Development and Human Capital

Anttila-Hughes, Jesse Keith January 2012 (has links)
Sustainable development is often taken to mean development that improves human well being subject to natural constraints over time, but in practice quantifying sustainability outcomes is often difficult. In this dissertation I seek to better elucidate the relationship between sustainable development and its natural constraints by focusing on human capital outcomes, which I argue provide one of our best summary statistics for "human well being" in general. Whether the constraints are imposed by natural systems (Chapters 2 and 3) or human ones (Chapter 4) I find strong evidence to suggest that attempts to pursue sustainable economic development must deal with nuanced and often conflicting interactions between the human capital invesment and accumulation process and its fundamental constraints.
19

Essays on Infrastructure and Development

Tompsett, Anna January 2014 (has links)
Spending on infrastructure accounts for several percentage points of global world product, reflecting its perceived importance to growth and development. Previous literature has made limited progress in providing unbiased estimates of its impacts, or causal evidence about policy changes that can alter this impact. Primarily, this is because of the selection problem: locations in which infrastructure is built differ from those in which it is not built. This dissertation provides evidence towards three important questions related to infrastructure and development. First, what role does manmade transport infrastructure play in determining and maintaining patterns of economic geography? Second, to what degree does the relocation of economic activity in response to changes in the transport infrastructure network affect estimates of the economic impact of those changes? Third, what is the effect of involving beneficiary communities in decision-making on projects to improve local infrastructure? To address the selection problem, Chapters 2 and 3 exploit quasi-experimental variation in distance to a land transport route created by the opening and location of bridges over major rivers in the historical United States, using a new dataset containing every bridge built over the Mississippi and Ohio rivers. Chapter 4 presents evidence from a randomized experiment in Bangladesh.
20

Innovation Strategies for a Global Manufacturing Business

Ramteke, Sachin Kakaji 01 January 2019 (has links)
Some global manufacturing businesses fail to reach an adequate level of financial performance within 5 years. The purpose of this single case study was to explore innovation strategies that business leaders of a global machinery manufacturing company in northwestern Illinois used to increase profit margins. The conceptual frameworks for this study included the holistic innovation model and the disruptive innovation theory. A purposeful sample of 9 business leaders who had more than 5 years of experience in the manufacturing industry and more than 2 years of experience using innovation strategies participated in the study. Data were collected from semistructured in-depth interviews and business documents, including multiyear strategic plans, annual reports, marketing campaign fliers, sustainability reports, customer needs documentation, statements, and other relevant information from the company's website. Data analysis involved manual and computer-aided techniques to compile the data, disassemble the data into codes, and reassemble the data into themes. The overarching theme emerging from data analysis was the importance of increasing a firm's competitiveness and sustaining profitable growth. There were 8 subthemes: distinctive customer experience, technology-based modernization, distinctive product quality, business model advantage, diversity of thoughts and inclusion, strategic partnerships and alliances, speed, and win in aftermarket. The implications of this study for positive social change include the potential to provide business leaders with evidence-based ideas to improve economic strength and sustainable development in the community.

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