ASU Electronic Theses and Dissertations
This collection includes most of the ASU Theses and Dissertations from 2011 to present. ASU Theses and Dissertations are available in downloadable PDF format; however, a small percentage of items are under embargo. Information about the dissertations/theses includes degree information, committee members, an abstract, supporting data or media.
In addition to the electronic theses found in the ASU Digital Repository, ASU Theses and Dissertations can be found in the ASU Library Catalog.
Dissertations and Theses granted by Arizona State University are archived and made available through a joint effort of the ASU Graduate College and the ASU Libraries. For more information or questions about this collection contact or visit the Digital Repository ETD Library Guide or contact the ASU Graduate College at gradformat@asu.edu.
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Description
The measurement of the radiation and convection that the human body experiences are important for ensuring safety in extreme heat conditions. The radiation from the surroundings on the human body is most often measured using globe or cylindrical radiometers. The large errors stemming from differences in internal and exterior temperatures and indirect estimation of convection can be resolved by simultaneously using three cylindrical radiometers (1 cm diameter, 9 cm height) with varying surface properties and internal heating. With three surface balances, the three unknowns (heat transfer coefficient, shortwave, and longwave radiation) can be solved for directly. As compared to integral radiation measurement technique, however, the bottom mounting using a wooden-dowel of the three-cylinder radiometers resulted in underestimated the total absorbed radiation. This first part of this thesis focuses on reducing the size of the three-cylinder radiometers and an alternative mounting that resolves the prior issues. In particular, the heat transfer coefficient in laminar wind tunnel with wind speed of 0.25 to 5 m/s is measured for six polished, heated cylinders with diameter of 1 cm and height of 1.5 to 9 cm mounted using a wooden dowel. For cylinders with height of 6 cm and above, the heat transfer coefficients are independent of the height and agree with the Hilpert correlation for infinitely long cylinder. Subsequently, a side-mounting for heated 6 cm tall cylinder with top and bottom metallic caps is developed and tested within the wind tunnel. The heat transfer coefficient is shown to be independent of the flow-side mounting and in agreement with the Hilpert correlation.
The second part of this thesis explores feasibility of employing the three-cylinder concept to measuring all air-flow parameters relevant to human convection including mean wind speed, turbulence intensity and length scale. Heated cylinders with same surface properties but varying diameters are fabricated. Uniformity of their exterior temperature, which is fundamental to the three-cylinder anemometer concept, is tested during operation using infrared camera. To provide a lab-based method to measure convection from the cylinders in turbulent flow, several designs of turbulence-generating fractal grids are laser-cut and introduced into the wind tunnel.
ContributorsGupta, Mahima (Author) / Rykaczewski, Konrad (Thesis advisor) / Pathikonda, Gokul (Thesis advisor) / Middel, Ariane (Committee member) / Arizona State University (Publisher)
Created2024
Description
Contraceptives are a vital part of reproductive care by preventing unwanted pregnancy, providing relief to premenstrual syndrome or PMS symptoms, and more. Birth control has been around for many centuries and has given women autonomy over their reproductive health. The Griswold v. Connecticut Supreme Court case in 1965 was the first ruling that made birth control accessible to the public under the law. However, this ruling only pertained only to married couples until the Eisenstadt v. Baird case in 1972. That case gave single women the ability to legally purchase contraceptives for themselves. In the decades since those rulings, many laws and policies have been put into place to give those in lower-income areas the ability to purchase contraceptives as well. With this increase in accessibility, those who use contraceptives, or are thinking of starting birth control, need to understand how to use it, when to use it, and the effects of using contraceptives. In the United States, nurses outnumber doctors by a 4:1 ratio and spend more time with patients than anyone else in a clinic or hospital environment. Nurses, being the main healthcare providers with whom a patient will interact, often are the ones patients ask questions about care and overall advice. Nurses must be able to relay valuable information about treatments or medicines, such as birth control, and give accurate information on the effects such treatments have. Nursing students need to be prepared. However, the amount of information provided, and opinions given might be affected by their nursing education, past experiences with birth control, and more. This project surveys nursing students at Arizona State University on their attitudes, behaviors, and beliefs towards birth control interventions, and how their individual experiences and education influence these perceptions.
ContributorsHiggins, Ilani Elyce (Author) / Gur-Arie, Rachel (Thesis advisor) / Ellison, Karin (Thesis advisor) / Maienschein, Jane (Committee member) / Arizona State University (Publisher)
Created2024
Description
Reactive oxygen species (ROS) including superoxide, hydrogen peroxide, and hydroxyl radicals occur naturally as a byproduct of aerobic respiration. To mitigate damages caused by ROS, Escherichia coli employs defenses including two cytosolic superoxide dismutases (SODs), which convert superoxide to hydrogen peroxide. Deletion of both sodA and sodB, the genes coding for the cytosolic SOD enzymes, results in a strain that is unable to grow on minimal medium without amino acid supplementation. Additionally, deletion of both cytosolic SOD enzymes in a background containing the relA1 allele, an inactive version of the relA gene that contributes to activation of stringent response by amino acid starvation, results in a strain that is unable to grow aerobically, even on rich medium. These observations point to a relationship between the stringent response and oxidative stress. To gain insight into this relationship, suppressors were isolated by growing the ∆sodAB relA1 cells aerobically on rich medium, and seven suppressors were further examined to characterize distinct colony sizes and temperature sensitivity phenotypes. In three of these suppressor-containing strains, the relA1 allele was successfully replaced by the wild type relA allele to allow further study in aerobic conditions. None of those three suppressors were found to increase tolerance to exogenous superoxides produced by paraquat, which shows that these mutations only overcome the superoxide buildup that naturally occurs from deletion of SODs. Because each of these suppressors had unique phenotypes, it is likely that they confer tolerance to SOD-dependent superoxide buildup by different mechanisms. Two of these three suppressors have been sent for whole-genome sequencing to identify the location of the suppressor mutation and determine the mechanism by which they confer superoxide tolerance.
ContributorsFlake, Melissa (Author) / Misra, Rajeev (Thesis advisor) / Shah, Dhara (Committee member) / Wang, Xuan (Committee member) / Arizona State University (Publisher)
Created2024
Description
There is increasing interest in growing strawberries (Fragaria ×ananassa) in indoor environments such as vertical farms, as the continued sustainability of outdoor
production is threatened due to reductions in arable land, labor shortages, and an
increased frequency of drought. However, the optimal conditions for growing
strawberries hydroponically in sole-source lighting conditions have yet to be established.
The objectives of this research were to investigate the optimal lighting conditions and
nutrient concentrations for strawberry production in vertical farming. In the first study,
bare-root plants of two strawberry cultivars, ‘Albion’ and ‘Monterey’, were grown in an
indoor vertical farm under a 22 °C air temperature and an 18-h photoperiod with 90
μmol·m−2·s−1 of blue light and 250 μmol·m−2·s−1 of red light with and without 50
μmol·m−2·s−1 of additional far-red light from light-emitting diodes. Adding far-red light
increased the fruit number per plant by 36%, total fruit fresh mass by 48%, and total
soluble solids content by 12% in ‘Albion’, but not ‘Monterey’. In the second study, bare
root plants of strawberries ‘Monterey’ and ‘San Andreas’ were grown under a 23 °C air
temperature and an 18-h photoperiod with an extended photosynthetic photon flux
density of 350 μmol·m−2·s−1. Plants were subjected to four potassium to nitrogen ratios
(K:N) of 1.5:1, 2.5:1, 3.5:1, and 4.5:1 in a deep-water culture hydroponic system.
Increasing K:N from 1.5:1 to 4.5:1 increased the root dry mass of ‘Monterey’, but
generally had little to no effect on vegetative growth in either cultivar. In addition, in
both cultivars, increasing K:N from 1.5:1 to 4.5:1 decreased individual fruit size and
increased titratable acidity. These results suggest that for indoor strawberry production,
including far-red light in sole-source lighting can improve fruit production in some
strawberry cultivars. However, increasing K:N in the hydroponic nutrient solution
generally does not benefit plant growth, fruit production, and fruit quality.
ContributorsRies, Jonathan (Author) / Park, Yujin (Thesis advisor) / Sagers, Cynthia (Committee member) / Meng, Qingwu (Committee member) / Arizona State University (Publisher)
Created2024
Description
The Northwest (NW) Atlantic porbeagle Lamna nasus is overfished and captured as bycatch in fisheries within the region. A comprehensive understanding of the population’s life history (e.g., reproduction) and habitat use, and the impact of capture with different gear types (e.g., post-release mortality) is needed to ensure effective fisheries management plans, develop bycatch mitigation strategies, and support stock recovery. This research used satellite tagging technologies to address gaps in knowledge needed to support management and conservation decisions for the NW Atlantic porbeagle. I provided the first estimate of post-release survival and recovery periods for immature porbeagles captured with rod-and-reel. Although survival was high (100%), juvenile porbeagles exhibited a recovery period in surface waters that may make them vulnerable to further fishing interactions. Next, I described the vertical habitat use of young porbeagles to recommend possible fishing modifications to reduce risk of capture. Young porbeagles spent more time in surface waters during summer compared to fall and during the night compared to day, suggesting that risk of capture may be reduced by setting gear deeper during summer and at night when this life stage’s behavior is reduced to the upper water column. Then, I provided an analysis of the seasonal and life stage-based habitat use of porbeagles. Space use was concentrated in continental shelf waters around Cape Cod, Massachusetts regardless of season and life stage. Given the relatively small and static high occupancy area overlaps with a high concentration of fishing activity, this region could be considered for spatial management of the NW Atlantic porbeagle. Finally, I used ultrasonography and satellite tagging to describe the three-dimensional habitat use of gravid porbeagles for the first time. Gravid porbeagles demonstrated seasonal differences in horizontal and vertical habitat use but spent most of the pupping season in waters southeast of Cape Cod or on Georges Bank, suggesting this region may be serving as a pupping ground for at least a portion of this population. Conservation efforts should focus on these important habitats to protect the next generation of porbeagles.
ContributorsAnderson, Brooke Nicole (Author) / Ferry, Lara (Thesis advisor) / Bowlby, Heather (Committee member) / Hammerschlag, Neil (Committee member) / Kang, Yun (Committee member) / Saul, Steven (Committee member) / Sulikowski, James (Committee member) / Arizona State University (Publisher)
Created2024
Description
The escalating global demand for food production underscores the urgent need for sustainable agricultural innovations. This research contributes new insights into the environmental benefits of using urine-derived phosphorus (P) fertilizers by closing the nutrient loop and applying the technology to agricultural food systems. Anticipatory life cycle assessment was used to quantify the environmental impacts of replacing conventionally mined P fertilizer with recovered urine-derived P fertilizer within the production of beef and plant-based burgers. Results shows that implementing recovered P fertilizer provides greater environmental benefits for all environmental impact categories, with global warming, eutrophication, and water consumption being the main impact categories examined in this study. Urine-derived P fertilizer use in beef burger production led to a 4% reduction in global warming impacts (3% for plant-based), 15% reduction in eutrophication (2% for plant-based), and 42% reduction in water consumption (46% for plant-based). Uncertainty in the results was accounted for using Monte Carlo simulation with 10,000 runs to rank the four burger production scenarios (e.g., conventional and urine-derived beef burger and conventional and urine-derived plant-based burger) based on their environmental impact on global warming, eutrophication, and water use under conditions of baseline, realistic, and maximum uncertainty. Under conditions of realistic uncertainty, implementing urine-derived P fertilizer for beef burger production was considered beneficial for global warming, eutrophication, and water consumption, with 78%, 99%, and 89% of the runs showing environmental benefits, respectively. Due to the lower P fertilizer requirements in plant-based burger production, uncertainty assessment under realistic conditions showed that a reduction in water use was the only expected benefit of implementing recovered P fertilizer, with 71% of the runs providing water use benefits. These results show that closing the nutrient loop by implementing urine-derived P fertilizers can be beneficial when applied to the correct agricultural food system (e.g., beef burger production) and is expected to have the most pronounced benefits with regard to water savings.
ContributorsEvans, Dilan (Author) / Boyer, Treavor (Thesis advisor) / Ravikumar, Dwarak (Thesis advisor) / Westerhoff, Paul (Committee member) / Arizona State University (Publisher)
Created2024
Structural Investigation of Quaternary Ammonium-Functionalized Networks for Gas Capture Applications
Description
As society moves to reduce the effects of climate change, there is a growing needfor the use of polymer science in technologies to mitigate the emission of carbon
dioxide. Networks containing quaternary ammonium groups with corresponding
HCO3 ions providing the mobile counter-charge in the networks have been reported
to capture carbon dioxide directly from the atmosphere through a moisture swing
mechanism, among other mechanisms. In this work, microstructural analysis of
synthesized polystyrene-based anion exchange networks is conducted using known
characterization techniques to better understand if variations in sorbent microstructure
adjust the distances between the quaternary ammonium groups. Additional surface
morphology studies of these sorbents are conducted. X-Ray Diffraction (XRD) spectra
reveal the amorphous structure of these polymers and the ability to adjust the distance
between quaternary ammonium groups by introducing different spacer groups and
various anions into the networks, which may affect the spontaneity of the CO2
to chemisorb to these sorbents. However, Wide Angle X-Ray Scattering (WAXS)
conflicts with the XRD data, indicating a change in distance between these groups is
not achieved. Additionally, WAXS data indicates an ability to increase the homogeneity
of structure in these materials by introducing larger counterions into the networks.
Small Angle X-Ray Scattering (SAXS) reveals no obvious large morphological features
in these sorbents, which is supported by Scanning Electron Microscopy (SEM) images.
In conclusion, XRD and WAXS experiments exhibit conflicting data regarding the
ability to adjust the distances between the quaternary ammonium groups in these
networks. Proposed actions to resolve this conflict are presented. Finally, SEM sheds
light on particle size and morphological features of these materials.
ContributorsBenard, Emmie Marie (Author) / Green, Matthew (Thesis advisor) / Jin, Kailong (Committee member) / Yang, Sui (Committee member) / Arizona State University (Publisher)
Created2024
Description
Waterborne opportunistic pathogens, particularly non-tuberculous mycobacteria(NTM), pose significant challenges to public health. This study aims to address critical gaps in understanding mycobacterial succession within premise plumbing systems, focusing on diversity, morphology, and factors influencing persistence. A premise plumbing pipe rack experiment was conducted with various pipe materials under real-world conditions. Water samples were collected and analyzed for NTM presence using culture-based and molecular techniques. During the cultivation of various isolates, two main morphologies were noted, revealing insights into the dynamics of mycobacterial communities within premise plumbing systems. Polymerase chain reaction (PCR) analysis attributed the yellow colonies to M. intracellulare or M. chimaera, while the white colonies represented unidentified mycobacterial species. The temporal dynamics of mycobacterial presence, assessed through PCR analysis over 7 weeks, demonstrated fluctuations influenced by source water conditions and disinfectant levels. Different pipe materials exhibited varying levels of mycobacterial colonization, with PVC pipes showing the highest percent positive. Species-level PCR analysis revealed dominance of M. intracellulare/M. chimaera in copper and PEX pipes, while "other" species were more prevalent in PVC pipes. The dominance of human-relevant species raises concerns for health, particularly among immunocompromised individuals. Future sequencing work is necessary to distinguish between M. intracellulare and M. chimaera, a differentiation that could provide valuable insights into the sources and transmission routes of these pathogens in the environment.
ContributorsCahill, Molly (Author) / Hamilton, Kerry A (Thesis advisor) / Boyer, Treavor (Committee member) / Voth-Gaeddert, Lee (Committee member) / Arizona State University (Publisher)
Created2024
Description
Mealworms (Tenebrio molitor), the larval stage of yellow mealworm beetles, are a popular feeder insect for birds, amphibians, reptiles, fish, and even human populations throughout the world. As such, the goal of this work was to understand how the diet of mealworms impacts their nutritional quality as variations in quality can impact the animals (and humans) that consume them. In this study, 500 mealworms were divided among each of the following substrates designed to model food sources available in urban versus rural, more natural areas: 100% wheat germ (control); 100% Styrofoam; mixture of soil, grasses, and leaves from urban lawns; a mixture of soil, grasses and leaves from rural lawns; 50% mixture of wheat germ + carrots; natural fertilizer; or fertilizer with weed killer. The mealworms were maintained at room temperature and the diets were replaced bi-weekly to prevent spoilage and to remove mealworm waste. Once a week for three weeks, mealworms were sampled from each substrate and frozen at -20°C. After 3 weeks, mealworms housed in wheat germ + carrots weighed significantly more than all other groups (p<0.05), whereas those housed in Styrofoam or urban lawn substrates weighed significantly less at week 3 as compared to week 1 (p<0.01). The urban lawn substrate resulted in greater molting and contained the highest number of pupae, but also the greatest mortality among the substrates. The Bradford method measured the total protein content of mealworms homogenized in phosphate-buffered saline. Mealworms maintained on wheat germ had significantly greater total protein content as compared to mealworms transitioned to any other diet (p<0.05). So, compared to wheat germ, urban foods generally reduced protein, total sugars, and crude fat, although they also decreased oxidized lipoproteins. Urban lawn had lower oxidized lipoprotein content than wheat germ, but levels were higher compared to wheat germ with carrots and natural fertilizer. In addition, urban foods generally increase the water content in mealworms. Urban foods were not much different from rural lawns as no there was difference between urban and rural lawns. Differences in body mass and total protein support the hypothesis that mealworms' nutritional quality is altered by ingesting urban substrates. These data suggest that mealworms (and potentially other insects) in cities may be exposed to food substrates that result in less nutritional value than those living in more natural areas as mimicked by the rural lawn substrates and wheat germ control, although they may be higher in water content.
ContributorsLockett, Rory Earle (Author) / Sweazea, Karen (Thesis advisor) / Deviche, Pierre (Committee member) / Senko, Jesse (Committee member) / Arizona State University (Publisher)
Created2024
Description
In order to optimize the ability of Geobacter sulfurreducens to produce electrical current and remediate wastewater, several physiological challenges must be overcome. The accumulation of protons at the electrode surface of a microbial fuel cell (MFC) decreases the pH, and, thus, the ability of the bacteria to maintain baseline metabolic conditions. To evaluate the extent to which this pH change hinders performance, the buffer concentration supplied to G. sulfurreducens reactors was varied. The resulting biofilms were subjected to chronoamperometry, cyclic voltammetry, and confocal microscopy to determine metabolic function and biofilm thickness. Biofilms grown with a 30-mM bicarbonate buffer experienced limitations on cell function and current output due to proton accumulation, while 90- and 150-mM conditions alleviated these limitations most of the measurements. Based on the current output, estimated biofilm thickness, and the medium-rate and slow-rate scan rate cyclic voltammetry, benefits exist for buffer concentrations greater than 30 mM. If the kinetics of G. sulfurreducens electron transfer are optimized, the potential of the technique to be implemented for energy recovery is improved.
ContributorsCoulam, Jordan (Author) / Torres, Cesar (Thesis advisor) / Delgado, Anca (Committee member) / Rittmann, Bruce (Committee member) / Arizona State University (Publisher)
Created2024