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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.
181

Environmental Impact Analysis of Flax Fibre Cultivation for Composite Reinforcement

Jacobsson, Elin January 2018 (has links)
Searching for environmentally sustainable alternatives for reinforcement of composite materials, flax fibre has one of the most promising potentials due to its desired mechanical properties. The fact that flax is a bio-material, in contrast to conventional synthetic fibres, does not ensure a less environmental impact. One of the major source of environmental impact related to flax fibre as a reinforcement material is the cultivation of flax fibre. In this study the environmental impact of flax fibre cultivation was studied by performing an environmental impact analysis with a life cycle assessment inspired approach.  The result showed that the quantification of the environmental impacts varied to a large extent depending on several parameters such as allocation method and whether carbon sequestration was included in the calculations. One striking example is the results for global warming potential, ranging from 10 000 kg CO2-equivivalents to a negative value per 1 tonne of flax fibre. The study showed the production and use of fertilizers to be the major contribution to the environmental impact by as much as 70-90 %. In order to limit the environmental impact from flax fibre cultivation suggested environmental improvements are to optimise the fertiliser use according to the flax type and soil conditions, improving nitrogen fixation as well as using organic fertilizers. / <p>2018-06-27</p>
182

Avaliação de Ciclo de Vida em processo de fabricação de rolamentos / Life Cycle assessment in bearing process manufacturing

Murbach Junior, Eduardo [UNESP] 23 February 2016 (has links)
Submitted by Eduardo Murbach Junior null (emurbach@yahoo.com.br) on 2016-04-26T01:22:34Z No. of bitstreams: 1 Avaliação de Ciclo de Vida em Processo de Fabricação de Rolamento.pdf: 4713134 bytes, checksum: a227fc8fe662842ed31c722e2242c43e (MD5) / Approved for entry into archive by Felipe Augusto Arakaki (arakaki@reitoria.unesp.br) on 2016-04-28T12:20:12Z (GMT) No. of bitstreams: 1 murbachjunior_e_me_bauru.pdf: 4713134 bytes, checksum: a227fc8fe662842ed31c722e2242c43e (MD5) / Made available in DSpace on 2016-04-28T12:20:12Z (GMT). No. of bitstreams: 1 murbachjunior_e_me_bauru.pdf: 4713134 bytes, checksum: a227fc8fe662842ed31c722e2242c43e (MD5) Previous issue date: 2016-02-23 / Este trabalho se propôs a realizar Avaliação de Ciclo de Vida em Processo de Fabricação de Rolamento de Agulhas, com intuito de identificar impacto ambiental nas etapas do processo de fabricação para eventual direcionamento de ações de melhorias em ternos ambientais, produtivos, e a título informativo. Foram mapeados processos de fabricação dos componentes do rolamento: anel interno, gaiola plástica de agulhas, agulhas e montagem. Os processos de fabricação apresentaram impactos ambientais nas categorias de combustíveis fósseis, respiráveis inorgânicos, alterações no clima, uso da terra, carcinogênicos, acidificação, ecotoxicidade e minerais, utilizando-se software SimaPro® e o método Eco-Indicator 99. Houve a identificação dos impactos ambientais provenientes de cada etapa do processo de fabricação de forma individual e global. / This scientific research offered to perform Life Cycle Assessment in Needles Bearing Process Manufacturing, with focus to identify environmental impacts in process manufacturing steps to eventual guidance of environmentally improvements actions, productivity, and informative notice as well. Manufacturing process components’ were identified inner ring, plastic cage, needles. The manufacture process presents environmental impacts in categories of fossil fuels, inorganic respirable, climate change, land use, carcinogens, acidification, ecotoxicity, minerals, according to software SimaPro® and method Eco-Indicator 99. The environmental impacts were identified concern to each manufacture process steps as individual and global conception.
183

The Effect of Urbanization on the Embodied Energy of Drinking Water in Tampa, Florida

Santana, Mark Vincent Eli 16 September 2015 (has links)
Increasing urbanization has serious implications for resource and energy use. One of these resources is drinking water. The increased amount of impervious surfaces associated with urban development is responsible for increased runoff during rain events, which may have a negative impact on the quality of nearby bodies of water, including drinking water sources. The growing populations associated with urbanization require a higher water demand. In addition, urban drinking water systems use energy to collect, treat, and distribute a safe reliable effluent to users. Therefore, this study focuses on the degree to which urbanization influences the embodied energy of drinking water in the city of Tampa via three objectives: (1) determine the degree to which the embodied energy of drinking water treatment is influenced by water quality possibly caused by urbanization, (2) determine the influence of urban form on the embodied energy of water supply, and (3) determine the effect of the state of water infrastructure on the embodied energy of drinking water. The influence of the water quality of the Hillsborough River Reservoir on the embodied energy of drinking water at the David L. Tippin Water Treatment Facility was determined and quantified via statistical analysis methods and life cycle energy analysis. Results show that energy due to electricity and fuel use (direct energy) is responsible for 63% of the embodied energy of drinking water treatment in the city of Tampa. However, the 37% of energy due to treatment chemical usage (indirect energy) is substantial and most influenced by influent water quality. Two constituents, total organic carbon and conductivity, are responsible for influencing 14.5% of Tampa’s drinking water treatment embodied energy. The effect of smart growth on the embodied energy of water supply was studied via the comparison of four future development scenarios within the Tampa WSA. The water consumption was estimated for each scenario and integrated into EPANET, a water distribution modeling software. After running each scenario, the embodied energy was calculated. The smart growth scenarios had 1-4% higher embodied energies than the business-as-usual scenario (urban sprawl). This was due to the location of added demand relative to the location of the water treatment facility. Nevertheless, while smart growth does not inherently minimize the embodied energy of water supply, it can result in the minimization of per capita water use due to the addition of more multi-family homes. About 16 pipe replacement scenarios were used to determine the degree to which the state of water infrastructure affects drinking water supply embodied energy. These scenarios were simulated using EPANET. The replacement of all pipes in the city of Tampa is estimated to result in an embodied energy decrease of about 20%. However, taking into account the energy use associated with pipe installation, only replacement of pipes that are older than 20 years with recycled ductile iron yields a net energy savings. The results of these studies show the influence of the roles that influent water quality, future urban development and infrastructure condition play on the embodied energy of drinking water in the Tampa WSA. However, future studies could look more in depth into these relationships via more definitive studies on the effect of land use on the Hillsborough River, and expanding the future development scenario studies to the metropolitan scale.
184

Finding the Future of Food: Sustainable Consumption Lessons from and for Veganism

January 2015 (has links)
abstract: Advancing sustainable food systems requires holistic understanding and solutions-oriented approaches that transcend disciplines, so expertise in a variety of subjects is necessary. Proposed solutions are usually technically or socially oriented, but disagreement over the best approach to the future of food dominates the dialogue. Technological optimists argue that scientific advances are necessary to feed the world, but environmental purists believe that reductions in consumption and waste are sufficient and less risky. Life cycle assessment (LCA) helps resolve debates through quantitative analysis of environmental impacts from products which serve the same function. LCA used to compare dietary choices reveals that simple plant-based diets are better for the environment than diets that include animal products. However, analysis of soy protein isolate (SPI) demonstrates that certain plant-based proteins may be less preferable for the environment than some unprocessed meats in several categories due to additional impacts that come from industrial processing. LCAs' focus on production risks ignoring consumers, but the food system exists to serve consumers, who can be major drivers of change. Therefore, the path to a sustainable food system requires addressing consumption issues as well. Existing methods for advancing sustainable food systems that equate more information with better behavior or performance are insufficient to create change. Addressing food system issues requires sufficient tacit knowledge to understand how arguments are framed, what the supporting content is, the findings of primary sources, and complex and controversial dialogue surrounding innovations and interventions for food system sustainability. This level of expertise is called interactional competence and it is necessary to drive and maintain holistic progress towards sustainability. Development strategies for interactional competence are informed by studying the motivations and strategies utilized by vegans. A new methodology helps advance understanding of expertise development by assessing levels of expertise and reveals insights into how vegans maintain commitment to a principle that influences their daily lives. The study of veganism and expertise reveals that while providing information to debunk fallacies is important, the development of tacit knowledge is fundamental to advance to a stage of competence. / Dissertation/Thesis / Doctoral Dissertation Sustainability 2015
185

Assessment and Solutions for Waste Handling of Compostable Biopolymers

January 2015 (has links)
abstract: Fossil resources have enabled the development of the plastic industry in the last century. More recently biopolymers have been making gains in the global plastics market. Biopolymers are plastics derived from plants, primarily corn, which can function very similarly to fossil based plastics. One difference between some of the dominant biopolymers, namely polylactic acid and thermoplastic starch, and the most common fossil-based plastics is the feature of compostability. This means that biopolymers represent not only a shift from petroleum and natural gas to agricultural resources but also that these plastics have potentially different impacts resulting from alternative disposal routes. The current end of life material flows are not well understood since waste streams vary widely based on regional availability of end of life treatments and the role that decision making has on waste identification and disposal. This dissertation is focused on highlighting the importance of end of life on the life-cycle of biopolymers, identifying how compostable biopolymer products are entering waste streams, improving collection and waste processing, and quantifying the impacts that result from the disposal of biopolymers. Biopolymers, while somewhat available to residential consumers, are primarily being used by various food service organizations trying to achieve a variety of goals such as zero waste, green advertising, and providing more consumer options. While compostable biopolymers may be able to help reduce wastes to landfill they do result in environmental tradeoffs associated with agriculture during the production phase. Biopolymers may improve the management for compostable waste streams by enabling streamlined services and reducing non-compostable fossil-based plastic contamination. The concerns about incomplete degradation of biopolymers in composting facilities may be ameliorated using alkaline amendments sourced from waste streams of other industries. While recycling still yields major benefits for traditional resins, bio-based equivalents may provide addition benefits and compostable biopolymers offer benefits with regards to global warming and fossil fuel depletion. The research presented here represents two published studies, two studies which have been accepted for publication, and a life-cycle assessment that will be submitted for publication. / Dissertation/Thesis / Doctoral Dissertation Civil and Environmental Engineering 2015
186

Sustainable Drinking Water Treatment: Using Weak Base Anion Exchange Sorbents Embedded With Metal Oxide Nanoparticles to Simultaneously Remove Multiple Oxoanions

January 2016 (has links)
abstract: Ion exchange sorbents embedded with metal oxide nanoparticles can have high affinity and high capacity to simultaneously remove multiple oxygenated anion contaminants from drinking water. This research pursued answering the question, “Can synthesis methods of nano-composite sorbents be improved to increase sustainability and feasibility to remove hexavalent chromium and arsenic simultaneously from groundwater compared to existing sorbents?” Preliminary nano-composite sorbents outperformed existing sorbents in equilibrium tests, but struggled in packed bed applications and at low influent concentrations. The synthesis process was then tailored for weak base anion exchange (WBAX) while comparing titanium dioxide against iron hydroxide nanoparticles (Ti-WBAX and Fe-WBAX, respectively). Increasing metal precursor concentration increased the metal content of the created sorbents, but pollutant removal performance and usable surface area declined due to pore blockage and nanoparticle agglomeration. An acid-post rinse was required for Fe-WBAX to restore chromium removal capacity. Anticipatory life cycle assessment identified critical design constraints to improve environmental and human health performance like minimizing oven heating time, improving pollutant removal capacity, and efficiently reusing metal precursor solution. The life cycle environmental impact of Ti-WBAX was lower than Fe-WBAX as well as a mixed bed of WBAX and granular ferric hydroxide for all studied categories. A separate life cycle assessment found the total number of cancer and non-cancer cases prevented by drinking safer water outweighed those created by manufacture and use of water treatment materials and energy. However, treatment relocated who bore the health risk, concentrated it in a sub-population, and changed the primary manifestation from cancer to non-cancer disease. This tradeoff was partially mitigated by avoiding use of pH control chemicals. When properly synthesized, Fe-WBAX and Ti-WBAX sorbents maintained chromium removal capacity while significantly increasing arsenic removal capacity compared to the parent resin. The hybrid sorbent performance was demonstrated in packed beds using a challenging water matrix and low pollutant influent conditions. Breakthrough curves hint that the hexavalent chromium is removed by anion exchange and the arsenic is removed by metal oxide sorption. Overall, the hybrid nano-sorbent synthesis methods increased sustainability, improved sorbent characteristics, and increased simultaneous removal of chromium and arsenic for drinking water. / Dissertation/Thesis / Doctoral Dissertation Civil and Environmental Engineering 2016
187

Computational Sustainability Assessment of Algal Biofuels and Bioproducts for Commercial Applications

January 2016 (has links)
abstract: To date, the production of algal biofuels is not economically sustainable due to the cost of production and the low cost of conventional fuels. As a result, interest has been shifting to high value products in the algae community to make up for the low economic potential of algal biofuels. The economic potential of high-value products does not however, eliminate the need to consider the environmental impacts. The majority of the environmental impacts associated with algal biofuels overlap with algal bioproducts in general (high-energy dewatering) due to the similarities in their production pathways. Selecting appropriate product sets is a critical step in the commercialization of algal biorefineries. This thesis evaluates the potential of algae multiproduct biorefineries for the production of fuel and high-value products to be economically self-sufficient and still contribute to climate change mandates laid out by the government via the Energy Independence and Security Act (EISA) of 2007. This research demonstrates: 1) The environmental impacts of algal omega-3 fatty acid production can be lower than conventional omega-3 fatty acid production, depending on the dewatering strategy. 2) The production of high-value products can support biofuels with both products being sold at prices comparable to 2016 prices. 3) There is a tradeoff between revenue and fuel production 4) There is a tradeoff between the net energy ratio of the algal biorefinery and the economic viability due to the lower fuel production in a multi-product model that produces high-value products and diesel vs. the lower economic potential from a multi-product model that just produces diesel. This work represents the first efforts to use life cycle assessment and techno-economic analysis to assess the economic and environmental sustainability of an existing pilot-scale biorefinery tasked with the production of high-value products and biofuels. This thesis also identifies improvements for multiproduct algal biorefineries that will achieve environmentally sustainable biofuel and products while maintaining economic viability. / Dissertation/Thesis / Doctoral Dissertation Civil and Environmental Engineering 2016
188

Avaliação do ciclo de vida de potenciais rotas de produção de hidrogênio: estudo dos sistemas de gaseificação da biomassa e de energia solar fotovoltaica / Life cycle assessment of hydrogen production routes: study of gaseification systems and photovoltaic solar power

FUKUROZAKI, SANDRA H. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:33:38Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:05:54Z (GMT). No. of bitstreams: 0 / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP
189

Beyond Recycling: Design for Disassembly, Reuse, and Circular Economy in the Built Environment

January 2018 (has links)
abstract: Today, we use resources faster than they can be replaced. Construction consumes more resources than any other industry and has one of the largest waste streams. Resource consumption and waste generation are expected to grow as the global population increases. The circular economy (CE) is based on the concept of a closed-loop cycle (CLC) and proposes a solution that, in theory, can eliminate the environmental impacts caused by construction and demolition (C&D) waste and increase the efficiency of resources’ use. In a CLC, building materials are reused, remanufactured, recycled, and reintegrated into other buildings (or into other sectors) without creating any waste. Designing out waste is the core principle of the CE. Design for disassembly or design for deconstruction (DfD) is the practice of planning the future deconstruction of a building and the reuse of its materials. Concepts like DfD, CE, and product-service systems (PSS) can work together to promote CLC in the built environment. PSS are business models based on stewardship instead of ownership. CE combines DfD, PSS, materials’ durability, and materials’ reuse in multiple life cycles to promote a low-carbon, regenerative economy. CE prioritizes reuse over recycling. Dealing with resource scarcity demands us to think beyond the incremental changes from recycling waste; it demands an urgent, systemic, and radical change in the way we design, build, and procure construction materials. This dissertation aims to answer three research questions: 1) How can researchers estimate the environmental benefits of reusing building components, 2) What variables are susceptible to affect the environmental impact assessment of reuse, and 3) What are the barriers and opportunities for DfD and materials’ reuse in the current design practice in the United States. The first part of this study investigated how different life cycle assessment (LCA) methods (i.e., hybrid LCA and process-based LCA), assumptions (e.g., reuse rates, transportation distances, number of reuses), and LCA timelines can affect the results of a closed-loop LCA. The second part of this study built on interviews with architects in the United States to understand why DfD is not part of the current design practice in the country. / Dissertation/Thesis / Doctoral Dissertation Civil, Environmental and Sustainable Engineering 2018
190

Decision Analysis for Comparative Life Cycle Assessment

January 2013 (has links)
abstract: Life Cycle Assessment (LCA) quantifies environmental impacts of products in raw material extraction, processing, manufacturing, distribution, use and final disposal. The findings of an LCA can be used to improve industry practices, to aid in product development, and guide public policy. Unfortunately, existing approaches to LCA are unreliable in the cases of emerging technologies, where data is unavailable and rapid technological advances outstrip environmental knowledge. Previous studies have demonstrated several shortcomings to existing practices, including the masking of environmental impacts, the difficulty of selecting appropriate weight sets for multi-stakeholder problems, and difficulties in exploration of variability and uncertainty. In particular, there is an acute need for decision-driven interpretation methods that can guide decision makers towards making balanced, environmentally sound decisions in instances of high uncertainty. We propose the first major methodological innovation in LCA since early establishment of LCA as the analytical perspective of choice in problems of environmental management. We propose to couple stochastic multi-criteria decision analytic tools with existing approaches to inventory building and characterization to create a robust approach to comparative technology assessment in the context of high uncertainty, rapid technological change, and evolving stakeholder values. Namely, this study introduces a novel method known as Stochastic Multi-attribute Analysis for Life Cycle Impact Assessment (SMAA-LCIA) that uses internal normalization by means of outranking and exploration of feasible weight spaces. / Dissertation/Thesis / M.S. Civil and Environmental Engineering 2013

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