Matching Items (150)
Description
With the ongoing drought surpassing a decade in Arizona, scholars, water managers and decision-makers have heightened attention to the availability of water resources, especially in rapidly growing regions where demand may outgrow supplies or outpace the capacity of the community water systems. Community water system managing entities and the biophysical and social characteristics of a place mediate communities' vulnerability to hazards such as drought and long-term climate change. The arid southwestern Phoenix metropolitan area is illustrative of the challenges that developed urban areas in arid climates face globally as population growth and climate change stress already fragile human-environmental systems. This thesis reveals the factors abating and exacerbating differential community water system vulnerability to water scarcity in communities simultaneously facing drought and rapid peri-urban growth. Employing a grounded, qualitative comparative case study approach, this thesis explores the interaction of social, biophysical and institutional factors as they effect the exposure, sensitivity and adaptive capacity of community water systems in Cave Creek and Buckeye, Arizona. Buckeye, once a small agricultural town in the West Valley, is wholly dependent on groundwater and currently planning for massive development to accommodate 218,591 new residents by 2020. Amid desert hills and near Tonto National Forest in the North Valley, Cave Creek is an upscale residential community suffering frequent water outages due to aging infrastructure and lack of system redundancy. Analyzing interviews, media accounts and policy documents, a narrative was composed explaining how place based factors, nested within a regional institutional water management framework, impact short and long-term vulnerability. This research adds to the library of vulnerability assessments completed using Polsky et al.'s Vulnerability Scoping Diagram and serves a pragmatic need assisting in the development of decision making tools that better represent the drivers of placed based vulnerability in arid metropolitan regions.
ContributorsZautner, Lilah (Author) / Larson, Kelli (Thesis advisor) / Bolin, Bob (Committee member) / Chhetri, Netra (Committee member) / Arizona State University (Publisher)
Created2011
Description
Arizona has an abundant solar resource and technologically mature systems are available to capture it, but solar energy systems are still considered to be an innovative technology. Adoption rates for solar and wind energy systems rise and fall with the political tides, and are relatively low in most rural areas in Arizona. This thesis tests the hypothesis that a consumer profile developed to characterize the adopters of renewable energy technology (RET) systems in rural Arizona is the same as the profile of other area residents who performed renovations, upgrades or additions to their homes. Residents of Santa Cruz and Cochise Counties who had obtained building permits to either install a solar or wind energy system or to perform a substantial renovation or upgrade to their home were surveyed to gather demographic, psychographic and behavioristic data. The data from 133 survey responses (76 from RET adopters and 57 from non-adopters) provided insights about their decisions regarding whether or not to adopt a RET system. The results, which are statistically significant at the 99% level of confidence, indicate that RET adopters had smaller households, were older and had higher education levels and greater income levels than the non-adopters. The research also provides answers to three related questions: First, are the energy conservation habits of RET adopters the same as those of non-adopters? Second, what were the sources of information consulted and the most important factors that motivated the decision to purchase a solar or wind energy system? And finally, are any of the factors which influenced the decision to live in a rural area in southeastern Arizona related to the decision to purchase a renewable energy system? The answers are provided, along with a series of recommendations that are designed to inform marketers and other promoters of RETs about how to utilize these results to help achieve their goals.
ContributorsPorter, Wayne Eliot (Author) / Reddy, T. Agami (Thesis advisor) / Pasqualetti, Martin (Committee member) / Larson, Kelli (Committee member) / Kennedy, Linda (Committee member) / Arizona State University (Publisher)
Created2011
Description
For some time it has been recognized amongst researchers that individual and collective change should be the goal in educating for sustainability, unfortunately education has generally been ineffective in developing pro-environmental behaviors among students. Still, many scholars and practitioners are counting on education to lead us towards sustainability but suggest that in order to do so we must transition away from current information-intensive education methods. In order to develop and test novel sustainability education techniques, this research integrates pedagogical methods with psychological knowledge to target well-established sustainable behaviors. Through integrating education, behavior change, and sustainability research, I aim to answer: How can we motivate sustainable behavioral change through education programs? More specifically: How do diverse knowledge domains (declarative, procedural, effectiveness, and social) influence sustainable behaviors, both in general as well as before and after a sustainability education program? And: What are barriers hindering education approaches to changing behaviors? In answering these questions, this research involved three distinct stages: (1) Developing a theoretical framework for educating for sustainability and transformative change; (2) Implementing a food and waste focused sustainability educational program with K-12 students and teachers while intensively assessing participants' change over the course of one year; (3) Developing and implementing an extensive survey that examines the quantitative relationships between diverse domains of knowledge and behavior among a large sample of K-12 educators. The results from the education program demonstrated that significant changes in knowledge and behaviors were achieved but social knowledge in terms of food was more resistant to change as compared to that of waste. The survey results demonstrated that K-12 educators have high levels of declarative (factual or technical) knowledge regarding anthropocentric impacts on the environment; however, declarative knowledge does not predict their participation in sustainable behaviors. Rather, procedural and social knowledge significantly influence participation in sustainable food behaviors, where as procedural, effectiveness, and social knowledge impact participation in sustainable waste behaviors. Overall, the findings from this research imply that in order to effectively educate for sustainability, we must move away from nature-centric approaches that focus on declarative knowledge and embrace different domains of knowledge (procedural, effectiveness, and social) that emphasis the social implications of change.
ContributorsRedman, Erin (Author) / Larson, Kelli (Thesis advisor) / Eakin, Hallie (Committee member) / Spielmann, Katherine (Committee member) / Arizona State University (Publisher)
Created2013
Description
In this thesis, we present the study of several physical properties of relativistic mat- ters under extreme conditions. We start by deriving the rate of the nonleptonic weak processes and the bulk viscosity in several spin-one color superconducting phases of quark matter. We also calculate the bulk viscosity in the nonlinear and anharmonic regime in the normal phase of strange quark matter. We point out several qualitative effects due to the anharmonicity, although quantitatively they appear to be relatively small. In the corresponding study, we take into account the interplay between the non- leptonic and semileptonic weak processes. The results can be important in order to relate accessible observables of compact stars to their internal composition. We also use quantum field theoretical methods to study the transport properties in monolayer graphene in a strong magnetic field. The corresponding quasi-relativistic system re- veals an anomalous quantum Hall effect, whose features are directly connected with the spontaneous flavor symmetry breaking. We study the microscopic origin of Fara- day rotation and magneto-optical transmission in graphene and show that their main features are in agreement with the experimental data.
ContributorsWang, Xinyang, Ph.D (Author) / Shovkovy, Igor (Thesis advisor) / Belitsky, Andrei (Committee member) / Easson, Damien (Committee member) / Peng, Xihong (Committee member) / Vachaspati, Tanmay (Committee member) / Arizona State University (Publisher)
Created2013
Description
Numerical simulations are very helpful in understanding the physics of the formation of structure and galaxies. However, it is sometimes difficult to interpret model data with respect to observations, partly due to the difficulties and background noise inherent to observation. The goal, here, is to attempt to bridge this gap between simulation and observation by rendering the model output in image format which is then processed by tools commonly used in observational astronomy. Images are synthesized in various filters by folding the output of cosmological simulations of gasdynamics with star-formation and dark matter with the Bruzual- Charlot stellar population synthesis models. A variation of the Virgo-Gadget numerical simulation code is used with the hybrid gas and stellar formation models of Springel and Hernquist (2003). Outputs taken at various redshifts are stacked to create a synthetic view of the simulated star clusters. Source Extractor (SExtractor) is used to find groupings of stellar populations which are considered as galaxies or galaxy building blocks and photometry used to estimate the rest frame luminosities and distribution functions. With further refinements, this is expected to provide support for missions such as JWST, as well as to probe what additional physics are needed to model the data. The results show good agreement in many respects with observed properties of the galaxy luminosity function (LF) over a wide range of high redshifts. In particular, the slope (alpha) when fitted to the standard Schechter function shows excellent agreement both in value and evolution with redshift, when compared with observation. Discrepancies of other properties with observation are seen to be a result of limitations of the simulation and additional feedback mechanisms which are needed.
ContributorsMorgan, Robert (Author) / Windhorst, Rogier A (Thesis advisor) / Scannapieco, Evan (Committee member) / Rhoads, James (Committee member) / Gardner, Carl (Committee member) / Belitsky, Andrei (Committee member) / Arizona State University (Publisher)
Created2012
Description
Understanding the temperature structure of protoplanetary disks (PPDs) is paramount to modeling disk evolution and future planet formation. PPDs around T Tauri stars have two primary heating sources, protostellar irradiation, which depends on the flaring of the disk, and accretional heating as viscous coupling between annuli dissipate energy. I have written a "1.5-D" radiative transfer code to calculate disk temperatures assuming hydrostatic and radiative equilibrium. The model solves for the temperature at all locations simultaneously using Rybicki's method, converges rapidly at high optical depth, and retains full frequency dependence. The likely cause of accretional heating in PPDs is the magnetorotational instability (MRI), which acts where gas ionization is sufficiently high for gas to couple to the magnetic field. This will occur in surface layers of the disk, leaving the interior portions of the disk inactive ("dead zone"). I calculate temperatures in PPDs undergoing such "layered accretion." Since the accretional heating is concentrated far from the midplane, temperatures in the disk's interior are lower than in PPDs modeled with vertically uniform accretion. The method is used to study for the first time disks evolving via the magnetorotational instability, which operates primarily in surface layers. I find that temperatures in layered accretion disks do not significantly differ from those of "passive disks," where no accretional heating exists. Emergent spectra are insensitive to active layer thickness, making it difficult to observationally identify disks undergoing layered vs. uniform accretion. I also calculate the ionization chemistry in PPDs, using an ionization network including multiple charge states of dust grains. Combined with a criterion for the onset of the MRI, I calculate where the MRI can be initiated and the extent of dead zones in PPDs. After accounting for feedback between temperature and active layer thickness, I find the surface density of the actively accreting layers falls rapidly with distance from the protostar, leading to a net outward flow of mass from ~0.1 to 3 AU. The clearing out of the innermost zones is possibly consistent with the observed behavior of recently discovered "transition disks."
ContributorsLesniak, Michael V., III (Author) / Desch, Steven J. (Thesis advisor) / Scannapieco, Evan (Committee member) / Timmes, Francis (Committee member) / Starrfield, Sumner (Committee member) / Belitsky, Andrei (Committee member) / Arizona State University (Publisher)
Created2012
Description
This thesis deals with the first measurements done with a cold neutron beam at the Spallation Neutron Source at Oak Ridge National Laboratory. The experimental technique consisted of capturing polarized cold neutrons by nuclei to measure parity-violation in the angular distribution of the gamma rays following neutron capture. The measurements presented here for the nuclei Chlorine ( 35Cl) and Aluminum ( 27Al ) are part of a program with the ultimate goal of measuring the asymmetry in the angular distribution of gamma rays emitted in the capture of neutrons on protons, with a precision better than 10-8, in order to extract the weak hadronic coupling constant due to pion exchange interaction with isospin change equal with one ( hπ 1). Based on theoretical calculations asymmetry in the angular distribution of the gamma rays from neutron capture on protons has an estimated size of 5·10-8. This implies that the Al parity violation asymmetry and its uncertainty have to be known with a precision smaller than 4·10-8. The proton target is liquid Hydrogen (H2) contained in an Aluminum vessel. Results are presented for parity violation and parity-conserving asymmetries in Chlorine and Aluminum. The systematic and statistical uncertainties in the calculation of the parity-violating and parity-conserving asymmetries are discussed.
ContributorsBalascuta, Septimiu (Author) / Alarcon, Ricardo (Thesis advisor) / Belitsky, Andrei (Committee member) / Doak, Bruce (Committee member) / Comfort, Joseph (Committee member) / Schmidt, Kevin (Committee member) / Arizona State University (Publisher)
Created2012
Description
As Arizona enters its fifteenth year of drought and Lake Mead hits historic lows, water management and policy planning will become increasingly important to ensure future water security in the Southwestern region of the United States. This thesis compares water demand trends and policies at the municipal level in Phoenix and Tucson, Arizona over the time period from 1980-2010. By analyzing gallons per capita per day (GPCD) trends for each city in the context of population growth, drought, and major state and local policies over the twenty year period, reasons for declines in per capita water demand were explored. Despite differences in their available water sources and political cultures, both the City of Phoenix and the City of Tucson have successfully reduced their per capita water consumption levels between 1980 and 2010. However, this study suggests that each city's measured success at reducing GPCD has been more a result of external events (supply augmentation, drought, and differing development trends) rather than conservation and demand reduction regulations adopted under the auspices of the Groundwater Management Act.
ContributorsSnyder, Rachel Claire (Author) / Larson, Kelli (Thesis director) / Hirt, Paul (Committee member) / Barrett, The Honors College (Contributor) / School of International Letters and Cultures (Contributor) / School of Sustainability (Contributor) / School of Politics and Global Studies (Contributor)
Created2015-05
Description
Pima was not the original name for the tribe of the Native Americans that lived along the Gila River, but their name is only one of many changes this tribe has faced due to the influence of outside sources. Pima was a name given to this tribe by the Spaniards during the 1600s. Throughout history the Pima have fought not only for their rights as a nation, but also for the rights of their beloved river, the Gila River. The relationship between the Pima tribe and Gila River is a very strong and deep connection. In fact, the Pima call themselves A-a'tam, which means "the people," and they identify with the Papago, a historical name for the Indians in the Sonoran Desert. A'kimult, which means "river" was added to their name as well. Being known as the River People may fit perfectly with this tribe due to their close knit and respectful relationship with the river over the decades (Russell, "The Pima Indians, 1975). Today the Pima call the Gila River Indian Community their main Tribal headquarters, which is located south of Phoenix. The Gila River Indian Community (GRIC) is part of both the Pinal and Maricopa counties and has a land area of 583.749 square miles ("Brownfields", 2010). Water deprivation and a bleak agricultural economy are challenges facing the Pima, which historically were strong in both areas. The Gila River has gone from a naturally flowing river to a restricted and nearly dried up waterbed. This research paper will examine the changes that both the Pima and the Gila River have undergone since settlers began to claim land in the late 1800's. It is my goal to look into the natural history and ecology of the Gila River and explain how this change has affected the Pima and their sustainability as a tribe. The ultimate goal is to have information easily accessible for reference for future research projects and to ] provide background information to help implement new programs and projects that will benefit the GRIC. Understanding the relationship between the Gila Valley and Pima will present areas where sustainable projects can improve the economy and society as a whole. The Native Americans who will be specifically addressed during this research are the tribes on the GRIC, which comprise the Akimel O-odham (Pima) and Pee Posh (Maricopa). These communities have a resident population of 15,084 and are located in the Maricopa and Pinal counties of central Arizona, to the south and east of metropolitan Phoenix ("Brownfields", 2010). Today the community is 372,000 acres and varies with an elevation of 935 feet to 1,450 feet ("Gila River", 2012). Literature will be the primary area of research along with informal discussions with employees of the GRIC. The Pimas' beliefs, interests, and practices will be addressed and researched; and review of the literature that deals with each problem they have faced as a result of the changing economy and society. By researching the relationship and proposing new ideas to help maintain the GRIC it will assure that the interests of the Pima are the priority. The potential that this research project can offer must encompass cultural sustainability, which is "developing, renewing and maintaining human cultures that create positive, enduring relationships with other peoples and the natural world" (Hawkes, 2001).
ContributorsRagan, McKenzie (Author) / Martinez, David (Thesis director) / Larson, Kelli (Committee member) / Manetta, Carol (Committee member) / Barrett, The Honors College (Contributor) / School of Sustainability (Contributor) / College of Public Programs (Contributor)
Created2012-12
Description
As the world energy demand increases, semiconductor devices with high energy conversion efficiency become more and more desirable. The energy conversion consists of two distinct processes, namely energy generation and usage. In this dissertation, novel multi-junction solar cells and light emitting diodes (LEDs) are proposed and studied for high energy conversion efficiency in both processes, respectively. The first half of this dissertation discusses the practically achievable energy conversion efficiency limit of solar cells. Since the demonstration of the Si solar cell in 1954, the performance of solar cells has been improved tremendously and recently reached 41.6% energy conversion efficiency. However, it seems rather challenging to further increase the solar cell efficiency. The state-of-the-art triple junction solar cells are analyzed to help understand the limiting factors. To address these issues, the monolithically integrated II-VI and III-V material system is proposed for solar cell applications. This material system covers the entire solar spectrum with a continuous selection of energy bandgaps and can be grown lattice matched on a GaSb substrate. Moreover, six four-junction solar cells are designed for AM0 and AM1.5D solar spectra based on this material system, and new design rules are proposed. The achievable conversion efficiencies for these designs are calculated using the commercial software package Silvaco with real material parameters. The second half of this dissertation studies the semiconductor luminescence refrigeration, which corresponds to over 100% energy usage efficiency. Although cooling has been realized in rare-earth doped glass by laser pumping, semiconductor based cooling is yet to be realized. In this work, a device structure that monolithically integrates a GaAs hemisphere with an InGaAs/GaAs quantum-well thin slab LED is proposed to realize cooling in semiconductor. The device electrical and optical performance is calculated. The proposed device then is fabricated using nine times photolithography and eight masks. The critical process steps, such as photoresist reflow and dry etch, are simulated to insure successful processing. Optical testing is done with the devices at various laser injection levels and the internal quantum efficiency, external quantum efficiency and extraction efficiency are measured.
ContributorsWu, Songnan (Author) / Zhang, Yong-Hang (Thesis advisor) / Menéndez, Jose (Committee member) / Ponce, Fernando (Committee member) / Belitsky, Andrei (Committee member) / Schroder, Dieter (Committee member) / Arizona State University (Publisher)
Created2010