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South Mountain is the largest municipal park in the nation. It is a bundled amenity, providing a series of linked services to the surrounding communities. A dataset of 19,209 homes in 155 neighborhoods within three miles of the park was utilized in order to complete a hedonic estimation for two nearby urban villages, Ahwatukee Foothills and South Mountain Village. Measures of access include proximity to the park, trailhead access, and adjacency to the park. Two regressions were estimated, the first including lot characteristics and subdivision fixed effects and the second using the coefficients for each subdivision as the dependent variable. These estimates describe how the location of a house in a subdivision contributes to its conditional mean price. As a result they offer a direct basis for capturing amenities measured at the neighborhood scale on home values. Park proximity, trailhead access and adjacency were found to significantly influence the price of homes at the 5% confidence level in Ahwatukee, but not in South Mountain Village. The results of this study can be applied to issues of environmental justice and park access in determining which areas and attributes of the park are associated with a high premium. Though South Mountain was preserved some time ago, development and future preservation in the City of Phoenix can be informed by such studies.
ContributorsRamakrishna, Saritha Kambhampati (Author) / Abbott, Joshua (Thesis director) / Smith, V. Kerry (Committee member) / Schoon, Michael (Committee member) / Barrett, The Honors College (Contributor) / School of Sustainability (Contributor) / Economics Program in CLAS (Contributor) / Department of English (Contributor)
Created2015-05
Description
Is nuclear power sustainable when compared to other energy sources? A truly sustainable energy source provides an environmental benefit, minimizes costs to consumers both socially and economically, and continues to do so in both the short and the long term. Taking the zero-carbon nature of nuclear generation as its net environmental benefit, this paper the evaluates the economic and social costs of nuclear power to determine if nuclear power's reputation as "unsustainable" is warranted. The sustainability of nuclear power is evaluated in two main categories. The first part focuses on the economics of nuclear power. There are many preconceived notions regarding nuclear power and its associated industry. This section addresses those notions to determine their validity given recent data. The prevalent types of nuclear plants across the U.S., the economics of the stages of nuclear energy production, and its competitiveness relative to other energy sources are addressed, culminating in an evaluation of its modern economic attractiveness as well as its future economic viability. A sustainability assessment would not be complete without addressing the social costs of an energy source, as a sustainable source must be both economically and socially viable. If it can be established that nuclear power can provide energy at lower rates and at a lower cost in terms of externalities, then it would be considered truly sustainable. To investigate those externalities, the second part of the analysis focuses on the human costs associated with the various stages of nuclear energy production. Those costs are then compared to those of alternatives sources of power, and selected case studies are examined to illustrate the ultimate risks associated with nuclear power operations. By quantifying these aspects and comparing the results to alternatives in the field, a better understanding of nuclear energy technology and its potential is achieved. The reader can then ascertain whether nuclear power's reputation as being "unsustainable" is, or is not, a reputation it deserves.
ContributorsRudolph, Alexander James (Author) / Miller, Clark (Thesis director) / Richter, Jennifer (Committee member) / School of Sustainability (Contributor) / School of Politics and Global Studies (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
Currently, approximately 40% of the world’s electricity is generated from coal and coal power plants are one of the major sources of greenhouse gases accounting for a third of all CO2 emissions. The Integrated Gasification Combined Cycle (IGCC) has been shown to provide an increase in plant efficiency compared to traditional coal-based power generation processes resulting in a reduction of greenhouse gas emissions. The goal of this project was to analyze the performance of a new SNDC ceramic-carbonate dual-phase membrane for CO2 separation. The chemical formula for the SNDC-carbonate membrane was Sm0.075Nd0.075Ce0.85O1.925. This project also focused on the use of this membrane for pre-combustion CO2 capture coupled with a water gas shift (WGS) reaction for a 1000 MW power plant. The addition of this membrane to the traditional IGCC process provides a purer H2 stream for combustion in the gas turbine and results in lower operating costs and increased efficiencies for the plant. At 900 °C the CO2 flux and permeance of the SNDC-carbonate membrane were 0.65 mL/cm2•min and 1.0×10-7 mol/m2•s•Pa, respectively. Detailed in this report are the following: background regarding CO2 separation membranes and IGCC power plants, SNDC tubular membrane preparation and characterization, IGCC with membrane reactor plant design, process heat and mass balance, and plant cost estimations.
ContributorsDunteman, Nicholas Powell (Author) / Lin, Jerry (Thesis director) / Dong, Xueliang (Committee member) / Barrett, The Honors College (Contributor) / Chemical Engineering Program (Contributor) / School of Sustainability (Contributor)
Created2014-05
Description
There are three known materials that readily undergo fission, allowing their use as a base for nuclear fuel: uranium-235, a naturally-occurring but uncommon isotope; plutonium, created from irradiated natural uranium; and uranium-233, produced from thorium. Of the three, uranium-235 and plutonium feature heavily in the modern nuclear industry, while uranium-233 and the thorium fuel cycle have failed to have significant presence in the field. Historically, nuclear energy development in the United States, and thorium development in particular, has been tied to the predominant societal outlook on the field, and thorium was only pursued seriously as an option during a period when nuclear energy was heavily favored, and resources seemed scarce. Recently, thorium-based energy has been experiencing a revival in interest in response to pollution concerns regarding fossil fuels. While public opinion is still wary of uranium, thorium-based designs could reduce reliance on fossil fuels while avoiding traditional drawbacks of nuclear energy. The thorium fuel cycle is more protected against proliferation, but is also much more expensive than the uranium-plutonium cycle in a typical reactor setup. Liquid-fueled molten salt reactor designs, however, bypass the prohibitive expense of U-233 refabrication by avoiding the stage entirely, keeping the chain reaction running with nothing but thorium input required. MSRs can use any fissile material as fuel, and are relatively safe to operate, due to passive features inherent to the design.
ContributorsGalbiati, Joseph Nicco (Author) / Martin, Thomas (Thesis director) / Foy, Joseph (Committee member) / Barrett, The Honors College (Contributor) / School of Sustainability (Contributor)
Created2014-05
Description
This paper seeks to analyze the relationship between energy subsidies on fossil fuels by countries and corresponding energy consumption, specifically electricity, by its citizens and occupants. The purpose of this was to determine whether pre-tax subsidies and post-tax subsidies have an effect on that consumption. This paper will discuss the prospect of accounting for post-tax subsidies as a method to curb rampant energy consumption throughout the world, with the focus being on residential electricity use. The two case studies, the Netherlands and Saudi Arabia, will illustrate the consumption patterns in relatively similar economic societies with different subsidy policies. Saudi Arabia will be a high pre-tax subsidy example while the Netherlands will be shown to account for some of the post-tax subsidies through an externality tax system. At the end of this analysis, this paper will show that the heavy subsidization of electricity production is strongly correlated to residential electricity consumption at levels that many officials would deem unsustainable, and that as such, subsidy reform is both beneficial and necessary.
ContributorsCorona, Kyle (Author) / Kelman, Jonathan (Thesis director) / Breetz, Hanna (Committee member) / School of Sustainability (Contributor, Contributor) / Economics Program in CLAS (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
Yearly changes in the consumer price index are used to adjust social security benefits in order to keep the purchasing power of social security beneficiaries the same. Currently, social security benefits are adjusted using a fixed-weighted price index that reflects the purchasing patterns of workers. However, some believe that a price index that captures the spending habits of the elderly should adjust monthly social security benefits, while others argue that a chain-weighted price index is a more accurate indexation technique. This report finds that if an elderly or chain-weighted price index were implemented this year, there would not be a significant change in the projected insolvency of the social security trust fund, but there could be a substantial decrease in the social security trust fund's yearly cash-flow deficit. Therefore, changing the indexation of social security benefits should not be seen as a short-term solvency fix. Instead, adjusting monthly social security benefits should be about keeping the purchasing power of beneficiaries relatively the same.
ContributorsScobas, Peter Jonathan (Author) / Hobijn, Bart (Thesis director) / Smith, Kerry (Committee member) / Economics Program in CLAS (Contributor) / School of Sustainability (Contributor) / School of Mathematical and Statistical Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
This honors thesis is focused on two separate catalysis projects conducted under the mentorship of Dr. Javier Pérez-Ramírez at ETH Zürich. The first project explored ethylene oxychlorination over supported europium oxychloride catalysts. The second project investigated alkyne semihydrogenation over nickel phosphide catalysts. This work is the subject of a publication of which I am a co-author, as cited below.
Project 1 Abstract: Ethylene Oxychlorination
The current two-step process for the industrial process of vinyl chloride production involves CuCl2 catalyzed ethylene oxychlorination to ethylene dichloride followed by thermal cracking of the latter to vinyl chloride. To date, no industrial application of a one-step process is available. To close this gap, this work evaluates a wide range of self-prepared supported CeO2 and EuOCl catalysts for one-step production of vinyl chloride from ethylene in a fixed-bed reactor at 623 773 K and 1 bar using feed ratios of C2H4:HCl:O2:Ar:He = 3:3 6:1.5 6:3:82 89.5. Among all studied systems, CeO2/ZrO2 and CeO2/Zeolite MS show the highest activity but suffer from severe combustion of ethylene, forming COx, while 20 wt.% EuOCl/γ-Al2O3 leads to the best vinyl chloride selectivity of 87% at 15.6% C2H4 conversion with complete suppression of CO2 formation and only 4% selectivity to CO conversion for over 100 h on stream. Characterization by XRD and EDX mapping reveals that much of the Eu is present in non-active phases such as Al2Eu or EuAl4, indicating that alternative synthesis methods could be employed to better utilize the metal. A linear relationship between conversion and metal loading is found for this catalyst, indicating that always part of the used Eu is available as EuOCl, while the rest forms inactive europium aluminate species. Zeolite-supported EuOCl slightly outperforms EuOCl/γ Al2O3 in terms of total yield, but is prone to significant coking and is unstable. Even though a lot of Eu seems locked in inactive species on EuOCl/γ Al2O3, these results indicate possible savings of nearly 16,000 USD per kg of catalyst compared to a bulk EuOCl catalyst. These very promising findings constitute a crucial step for process intensification of polyvinyl chloride production and exploring the potential of supported EuOCl catalysts in industrially-relevant reactions.
Project 2 Abstract: Alkyne Semihydrogenation
Despite strongly suffering from poor noble metal utilization and a highly toxic selectivity modifier (Pb), the archetypal catalyst applied for the three-phase alkyne semihydrogenation, the Pb-doped Pd/CaCO3 (Lindlar catalyst), is still being utilized at industrial level. Inspired by the very recent strategies involving the modification of Pd with p-block elements (i.e., S), this work extrapolates the concept by preparing crystalline metal phosphides with controlled stoichiometry. To develop an affordable and environmentally-friendly alternative to traditional hydrogenation catalysts, nickel, a metal belonging to the same group as Pd and capable of splitting molecular hydrogen has been selected. Herein, a simple two-step synthesis procedure involving nontoxic precursors was used to synthesize bulk nickel phosphides with different stoichiometries (Ni2P, Ni5P4, and Ni12P5) by controlling the P:Ni ratios. To uncover structural and surface features, this catalyst family is characterized with an array of methods including X-ray diffraction (XRD), 31P magic-angle nuclear magnetic resonance (MAS-NMR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). Bulk-sensitive techniques prove the successful preparation of pure phases while XPS analysis unravels the facile passivation occurring at the NixPy surface that persists even after reductive treatment. To assess the characteristic surface fingerprints of these materials, Ar sputtering was carried out at different penetration depths, reveling the presence of Ni+ and P-species. Continuous-flow three-phase hydrogenations of short-chain acetylenic compounds display that the oxidized layer covering the surface is reduced under reaction conditions, as evidenced by the induction period before reaching the steady state performance. To assess the impact of the phosphidation treatment on catalytic performance, the catalysts were benchmarked against a commercial Ni/SiO2-Al2O3 sample. While Ni/SiO2-Al2O3 presents very low selectivity to the alkene (the selectivity is about 10% at full conversion) attributed to the well-known tendency of naked nickel nanoparticles to form hydrides, the performance of nickel phosphides is highly selective and independent of P:Ni ratio. In line with previous findings on PdxS, kinetic tests indicate the occurrence of a dual-site mechanism where the alkyne and hydrogen do not compete for the same site.
This work is the subject of a publication of which I am a co-author, as cited below.
D. Albani; K. Karajovic; B. Tata; Q. Li; S. Mitchell; N. López; J. Pérez-Ramírez. Ensemble Design in Nickel Phosphide Catalysts for Alkyne Semi-Hydrogenation. ChemCatChem 2019. doi.org/10.1002/cctc.201801430
Project 1 Abstract: Ethylene Oxychlorination
The current two-step process for the industrial process of vinyl chloride production involves CuCl2 catalyzed ethylene oxychlorination to ethylene dichloride followed by thermal cracking of the latter to vinyl chloride. To date, no industrial application of a one-step process is available. To close this gap, this work evaluates a wide range of self-prepared supported CeO2 and EuOCl catalysts for one-step production of vinyl chloride from ethylene in a fixed-bed reactor at 623 773 K and 1 bar using feed ratios of C2H4:HCl:O2:Ar:He = 3:3 6:1.5 6:3:82 89.5. Among all studied systems, CeO2/ZrO2 and CeO2/Zeolite MS show the highest activity but suffer from severe combustion of ethylene, forming COx, while 20 wt.% EuOCl/γ-Al2O3 leads to the best vinyl chloride selectivity of 87% at 15.6% C2H4 conversion with complete suppression of CO2 formation and only 4% selectivity to CO conversion for over 100 h on stream. Characterization by XRD and EDX mapping reveals that much of the Eu is present in non-active phases such as Al2Eu or EuAl4, indicating that alternative synthesis methods could be employed to better utilize the metal. A linear relationship between conversion and metal loading is found for this catalyst, indicating that always part of the used Eu is available as EuOCl, while the rest forms inactive europium aluminate species. Zeolite-supported EuOCl slightly outperforms EuOCl/γ Al2O3 in terms of total yield, but is prone to significant coking and is unstable. Even though a lot of Eu seems locked in inactive species on EuOCl/γ Al2O3, these results indicate possible savings of nearly 16,000 USD per kg of catalyst compared to a bulk EuOCl catalyst. These very promising findings constitute a crucial step for process intensification of polyvinyl chloride production and exploring the potential of supported EuOCl catalysts in industrially-relevant reactions.
Project 2 Abstract: Alkyne Semihydrogenation
Despite strongly suffering from poor noble metal utilization and a highly toxic selectivity modifier (Pb), the archetypal catalyst applied for the three-phase alkyne semihydrogenation, the Pb-doped Pd/CaCO3 (Lindlar catalyst), is still being utilized at industrial level. Inspired by the very recent strategies involving the modification of Pd with p-block elements (i.e., S), this work extrapolates the concept by preparing crystalline metal phosphides with controlled stoichiometry. To develop an affordable and environmentally-friendly alternative to traditional hydrogenation catalysts, nickel, a metal belonging to the same group as Pd and capable of splitting molecular hydrogen has been selected. Herein, a simple two-step synthesis procedure involving nontoxic precursors was used to synthesize bulk nickel phosphides with different stoichiometries (Ni2P, Ni5P4, and Ni12P5) by controlling the P:Ni ratios. To uncover structural and surface features, this catalyst family is characterized with an array of methods including X-ray diffraction (XRD), 31P magic-angle nuclear magnetic resonance (MAS-NMR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). Bulk-sensitive techniques prove the successful preparation of pure phases while XPS analysis unravels the facile passivation occurring at the NixPy surface that persists even after reductive treatment. To assess the characteristic surface fingerprints of these materials, Ar sputtering was carried out at different penetration depths, reveling the presence of Ni+ and P-species. Continuous-flow three-phase hydrogenations of short-chain acetylenic compounds display that the oxidized layer covering the surface is reduced under reaction conditions, as evidenced by the induction period before reaching the steady state performance. To assess the impact of the phosphidation treatment on catalytic performance, the catalysts were benchmarked against a commercial Ni/SiO2-Al2O3 sample. While Ni/SiO2-Al2O3 presents very low selectivity to the alkene (the selectivity is about 10% at full conversion) attributed to the well-known tendency of naked nickel nanoparticles to form hydrides, the performance of nickel phosphides is highly selective and independent of P:Ni ratio. In line with previous findings on PdxS, kinetic tests indicate the occurrence of a dual-site mechanism where the alkyne and hydrogen do not compete for the same site.
This work is the subject of a publication of which I am a co-author, as cited below.
D. Albani; K. Karajovic; B. Tata; Q. Li; S. Mitchell; N. López; J. Pérez-Ramírez. Ensemble Design in Nickel Phosphide Catalysts for Alkyne Semi-Hydrogenation. ChemCatChem 2019. doi.org/10.1002/cctc.201801430
ContributorsTata, Bharath (Author) / Deng, Shuguang (Thesis director) / Muhich, Christopher (Committee member) / Chemical Engineering Program (Contributor, Contributor) / School of Sustainability (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
Existing research into the health benefits of insurance fall into two major categories \u2014 observational and experimental. Observational studies have centered on data sets from before 2000 and focus on the mortality differences between the privately insured and the uninsured. Experimental studies began with Massachusetts' 2006 health reform and continued after the passage of the Affordable Care Act. These studies measure the effects of public insurance among the coverage expansion populations. These two bodies of literature come to ambiguous and contradictory conclusions to the mortality effects and health value of insurance. This study extends the observational methodologies to the publicly insured in samples from the National Health and Nutrition Examination Survey in both the 1988-1994 survey and the 2001-2002 survey. Using the Cox Proportional Hazard model, this study estimates the hazard ratios faced by the privately and publicly insured compared to the uninsured. This study finds the publicly insured face hazards 1.5 times those of the uninsured (p<.001), while the privately insured do not face hazards significantly different from those of the uninsured. Literature suggests that some unobserved characteristic of the publicly insured are influencing their mortality. Interacting with participants health reveals that these differences across groups shrink as health declines. Experimental literature suggests that public insurance lowers the uninsured risk from "healthcare amenable" conditions. Treatment of these conditions may explain the hazard reductions among the uninsured in non-excellent health. The high risk of the publicly insured in excellent health defies explanation.
ContributorsMorita, Aidan James Donnelly (Author) / Veramendi, Gregory (Thesis director) / Zafar, Basit (Committee member) / School of Mathematical and Statistical Sciences (Contributor) / Economics Program in CLAS (Contributor) / School of Sustainability (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
This thesis looks at the theory and empirical evidence that surrounds the debate between environmentalists and economists regarding the link between trade liberalization and environmental degradation. The main points of the theory are the scale, composition, and technique effects which, when aggregated, are ambiguous as the harm or benefit of trade's effect on the environment. The empirical evidence studied ranges in time periods from the early 1990s to 2011 and mainly focuses on the existence or absence of an environmental Kuznets curve for certain pollutant. However, the data still proves to be inconclusive. The debate about the possible link between trade and the environment is as important as ever, especially in regards to carbon dioxide emissions. Going forward, it is extremely important that international cooperation regarding emissions targets and abatement goals increases. Trade will prove to be an invaluable tool in this endeavor as it provides a mechanism for the spread of green technology as well as can be used as a method of environmental policy enforcement.
ContributorsCotterell, Emily Claire (Author) / Mendez, Jose (Thesis director) / McDaniel, Cara (Committee member) / School of Sustainability (Contributor) / Department of Economics (Contributor) / Department of Supply Chain Management (Contributor) / W. P. Carey School of Business (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Climate change is impacting fisheries through ecological shifts altering the geographical distribution and quantity of fish species. About 60% of United States fish caught by volume is caught in the Alaska region, with Alaska's economy dependent on fisheries. Additionally, fisheries are an important source of employment for many Alaskan communities. Therefore, it is important to have policies and strategies in place to prepare for ongoing climate impacts. One step to support better tailoring policy to support those most likely to be negatively impacted is to identify the fishing communities most vulnerable to climate change. This study uses data on vulnerable fish species and fishery catch by species and community to identify what communities are most vulnerable to changing climate conditions. I identify 26 communities that are fishing climate vulnerable species. I then use vulnerable fish species revenue data to identify communities most at risk either because they generate a substantial amount of revenue from these species or a substantial proportion of their total revenue is derived from these species. Using species-specific revenue, I show that Sablefish contribute the most to this vulnerability.
ContributorsFulton, Breanna (Author) / Kroetz, Kailin (Thesis director) / Abbot, Joshua (Committee member) / Barrett, The Honors College (Contributor) / School of Sustainability (Contributor) / School of Geographical Sciences and Urban Planning (Contributor)
Created2023-05