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With the growing popularity of 3d printing in recreational, research, and commercial enterprises new techniques and processes are being developed to improve the quality of parts created. Even so, the anisotropic properties is still a major hindrance of parts manufactured in this method. The goal is to produce parts that

With the growing popularity of 3d printing in recreational, research, and commercial enterprises new techniques and processes are being developed to improve the quality of parts created. Even so, the anisotropic properties is still a major hindrance of parts manufactured in this method. The goal is to produce parts that mimic the strength characteristics of a comparable part of the same design and materials created using injection molding. In achieving this goal the production cost can be reduced by eliminating the initial investment needed for the creation of expensive tooling. This initial investment reduction will allow for a wider variant of products in smaller batch runs to be made available. This thesis implements the use of ultraviolet (UV) illumination for an in-process laser local pre-deposition heating (LLPH). By comparing samples with and without the LLPH process it is determined that applied energy that is absorbed by the polymer is converted to an increase in the interlayer temperature, and resulting in an observed increase in tensile strength over the baseline test samples. The increase in interlayer bonding thus can be considered the dominating factor over polymer degradation.
ContributorsKusel, Scott Daniel (Author) / Hsu, Keng (Thesis advisor) / Sodemann, Angela (Committee member) / Kannan, Arunachala M (Committee member) / Arizona State University (Publisher)
Created2017
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Plastic is a valuable part of the consumer economy, but it creates negative environmental externalities throughout its lifecycle. To reduce these effects, a sustainable circular economy is needed, where more plastic is diverted from landfill or environmental sinks through reduction, reuse, recycling, or composting, while addressing social needs. Although many

Plastic is a valuable part of the consumer economy, but it creates negative environmental externalities throughout its lifecycle. To reduce these effects, a sustainable circular economy is needed, where more plastic is diverted from landfill or environmental sinks through reduction, reuse, recycling, or composting, while addressing social needs. Although many different stakeholders (industry, academia, policymakers) are calling for a sustainable circular economy for plastics, globally, less than 20% of plastic is recycled with no data on reduction and reuse. In this dissertation, a mixed methods approach is used to suggest how organizations related to the plastic industry can implement a sustainable circular economy. The first chapter identifies how firms across the plastic value chain can innovate to adopt a sustainable circular flow. A systematic review reveals over 300 examples, which are used to create a material flow typology. Findings summarize five critical points of innovation and indicate that innovation adoption is low. More concerted efforts are needed to improve innovation adoption and there is a need to shift innovation focus from resource efficiency to sustainability. The second chapters studies U.S. plastic recyclers’ price signals to generate evidence for favorable recycling policies. A hedonic analysis reveals recyclers preferences for recyclability – plastic properties that enable recycling. Results suggest that adequate recycling infrastructure and absence of virgin plastic can play an important role in facilitating more recycling. In the third paper, the role of governments as consumers is studied. As the largest consumers in a market, governments can signal a large demand for circular products and services, however public administration literature has paid limited attention to it. A theoretical framework is created to fill the knowledge gap and suggest how governments can use sustainable public procurement for a circular economy. A systematic literature review of the top ten public administration journals over 32 years reveals critical knowledge gaps and the potential for important sustainable public procurement research
ContributorsHafsa, Fatima (Author) / Englin, Jeffrey (Thesis advisor) / Abbott, Joshua K (Committee member) / Darnall, Nicole (Committee member) / Dooley, Kevin J (Committee member) / Arizona State University (Publisher)
Created2022