Matching Items (263)
Filtering by

Clear all filters

131046-Thumbnail Image.png
Description
As Energy needs grow and photovoltaics expand to meet humanity’s demand for electricity, waste modules will start building up. Tao et. al. propose a recycling process to recover all precious solar cell materials, a process estimated to generate a potential $15 billion in revenue by 2050. A key part of

As Energy needs grow and photovoltaics expand to meet humanity’s demand for electricity, waste modules will start building up. Tao et. al. propose a recycling process to recover all precious solar cell materials, a process estimated to generate a potential $15 billion in revenue by 2050. A key part of this process is metal recovery, and specifically, silver recovery. Silver recovery via electrowinning was studied using a hydrofluoric acid leachate/electrolyte. Bulk electrolysis trials were performed at varied voltages using a silver working electrode, silver pseudo-reference electrode and a graphite counter-electrode. The highest mass recovery achieved was 98.8% which occurred at 0.65 volts. Product purity was below 90% for all trials and coulombic efficiency never reached above 20%. The average energy consumption per gram of reduced silver was 2.16kWh/kg. Bulk electrolysis indicates that parasitic reactions are drawing power from the potentiostat and limiting the mass recovery of the system. In order to develop this process to the practical use stage, parasitic reactions must be eliminated, and product purity and power efficiency must improve. The system should be run in a vacuum environment and the reduction peaks in the cell should be characterized using cyclic voltammetry.
ContributorsTezak, Cooper R (Author) / Tao, Meng (Thesis director) / Phelan, Patrick (Committee member) / Chemical Engineering Program (Contributor) / School of International Letters and Cultures (Contributor) / Barrett, The Honors College (Contributor)
Created2020-12
130952-Thumbnail Image.png
DescriptionThis study was designed to evaluate the 2019 novel coronavirus (COVID-19) impact and its profound effect on the American oil industry.
ContributorsEberlein, Nikolas Carl (Co-author) / Chow, Brandon (Co-author) / LaRosa, Julia (Thesis director) / Fleischner, Robert (Committee member) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2020-12
131037-Thumbnail Image.png
Description
Biofuels are a carbon-neutral energy source proving to be a sustainable alternative to greenhouse gas-emitting fossil fuels that are accelerating the detrimental effects of anthropogenic climate change. A developing system aimed at more efficiently producing biofuels is called Microbial Electro-Photosynthesis (MEPS). In MEPS, a Synechocystis sp. PCC 6803 mutant lacking

Biofuels are a carbon-neutral energy source proving to be a sustainable alternative to greenhouse gas-emitting fossil fuels that are accelerating the detrimental effects of anthropogenic climate change. A developing system aimed at more efficiently producing biofuels is called Microbial Electro-Photosynthesis (MEPS). In MEPS, a Synechocystis sp. PCC 6803 mutant lacking photosystem II (PSII) receives electrons by a hydroduroquinone (DQH2) mediator from a more efficient water-splitting electrochemical cell, rather than splitting water itself using PSII. However, growth of the Synechocystis cells prior to use in MEPS requires an organic carbon source, leading to internally-stored electron sources, namely glycogen, that compete with preferred DQH2 mediator-delivered electrons. In this study, the effects of organic carbon source (pyruvate, acetate, glucose, and no carbon source) and light condition (light or dark) on the physiology and P700+ reduction kinetics of photoheterotrophically grown Synechocystis mutants were studied with the hope of identifying a maintenance culturing method that allowed for both cell viability and mitigated glycogen storage. While no significant decreases in internal electron-sources were found with these methods, it was observed that Synechocystis cells fed pyruvate in the light had most successfully reduced competition between internal electron sources and preferred DQH2-delivered electrons. This study suggests that these experiments be re-run after removing exogenous carbon sources and that the nutrients available to the cells and their effects on pyruvate and acetate uptake be further investigated.
ContributorsMangus, Anna Michelle (Author) / Torres, Cesar (Thesis director) / Lewis, Christine (Committee member) / Chemical Engineering Program (Contributor) / School of Sustainability (Contributor) / Barrett, The Honors College (Contributor)
Created2020-12
131038-Thumbnail Image.png
Description
Water scarcity is still an issue across the globe, so nonconventional desalination methods need to be developed to be able to get access to clean, safe water. One such method being studied is the pervaporation system, a membrane process that uses a vapor pressure differential to drive the system. There

Water scarcity is still an issue across the globe, so nonconventional desalination methods need to be developed to be able to get access to clean, safe water. One such method being studied is the pervaporation system, a membrane process that uses a vapor pressure differential to drive the system. There is a need to find the efficiency of the cold trap condenser that is used to collect the permeate so that a thermodynamic model can be fully developed to assist in the development of an industrial scale pervaporation system. An efficiency was not able to be confidently found, but it is believe to be between 95-100%.
Created2020-12
130865-Thumbnail Image.png
Description

The goal of this research was to identify why the federal government should invest in solar research and development, and which areas of solar improvement should be focused on. Motivation for this can be found in the pressing need to prevent and reverse the effects of climate change, the inevitability

The goal of this research was to identify why the federal government should invest in solar research and development, and which areas of solar improvement should be focused on. Motivation for this can be found in the pressing need to prevent and reverse the effects of climate change, the inevitability of fossil fuel resources eventually running out, and the economic and job creation potential which solar energy holds. Additionally, it is important to note that the best course of action will involve a split of funding between current solar rollout and energy grid updating, and the R&D listed in this research. Upon examination, it can be seen that an energy revolution, led by a federal solar jobs program and a Green New Deal, would be both an ethically and economically beneficial solution. A transition from existing fossil fuel infrastructure to renewable, solar-powered infrastructure would not only be possible but highly beneficial in many aspects, including massive job creation, a more affordable, renewable energy solution to replace coal-fired plants, and no fuel spending or negotiation required.<br/>When examining which areas of solar improvement to focus on for R&D funding, four primary areas were identified, with solutions presented for each. These areas for improvement are EM capture, EM conversion efficiency, energy storage capacity, and the prevention of overheating. For each of these areas of improvement, affordable solutions that would greatly improve the efficiency and viability of solar as a primary energy source were identified. The most notable area that should be examined is solar storage, which would allow solar PV panels to overcome their greatest real and perceived obstacle, which is the inconsistent power generation. Solar storage is easily attainable, and with enough storage capacity, excess solar energy which would otherwise be wasted during the day can be stored and used during the night or cloudy weather as necessary. Furthermore, the implementation of highly innovative solutions, such as agrivoltaics, would allow for a solar revolution to occur.

ContributorsWhitlow, Hunter Marshall (Author) / Fong, Benjamin (Thesis director) / Andino, Jean (Committee member) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
130902-Thumbnail Image.png
Description
Protein crystallization is a technique for the formation of three-dimensional protein crystals, which is widely utilized by scientists, engineers, and researchers. Protein crystallography allows for protein structures and functions to be studied. As proteins play a central role in biological systems and life itself, a deeper understanding of their structure-function

Protein crystallization is a technique for the formation of three-dimensional protein crystals, which is widely utilized by scientists, engineers, and researchers. Protein crystallography allows for protein structures and functions to be studied. As proteins play a central role in biological systems and life itself, a deeper understanding of their structure-function properties is crucial to elucidating fundamental behaviors, such as protein folding in addition to the role that they play in emerging fields, such as, tissue engineering with application to the emerging field of regenerative medicine. However, a significant limitation toward achieving further advancements in this field is that in order to determine detailed structure of proteins from protein crystals, high-quality and larger size protein crystals are needed. Because it is difficult to produce adequate size, high-quality crystals, it remains difficult to determine the structure of many proteins. However, a new method using a microgravity environment to crystallize proteins has proven effective through various studies conducted on the International Space Station (ISS). In the presence of microgravity, free convection is essentially absent in the bulk solution where crystallization occurs, thus allowing for purely random Brownian motion to exist which favors the nucleation and growth of high-quality protein crystals. Many studies from the ISS to date have demonstrated that growing protein crystals in a microgravity environment produces larger and higher-quality crystals. This method provides new opportunities for better structure identification and analysis of proteins. Although there remains many more limitations and challenges in the field, microgravity protein crystallization holds many opportunities for the future of biotechnology and scientific development. The objective of this thesis was to study the crystallization of hen egg white lysozyme (HEWL) and determine the effects of both unit and microgravity on growth/size and quality of HEWL. Through preliminary trials using a universal ground-based reduced-gravity system, the crystallization of HEWL in a simulated microgravity environment was successfully conducted and the results reported are promising. The utility of continuous, scalable ground-based, microgravity platforms for studies on a wide range of material systems and behavior, such as, protein crystallization, has significant implications regarding its impact on many industries, including drug development as well as regenerative medicine.
ContributorsTran, Amanda Marie (Author) / Pizziconi, Vincent (Thesis director) / Alford, Terry (Committee member) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2020-12
130847-Thumbnail Image.png
Description

A survey of 133 engineering students at Arizona State University (ASU) was conducted to determine if extracurricular activities correlated to the amount of internships a student receives. The problem that ASU engineering students are having is that finding an internship during college and consequently finding a job after graduation is

A survey of 133 engineering students at Arizona State University (ASU) was conducted to determine if extracurricular activities correlated to the amount of internships a student receives. The problem that ASU engineering students are having is that finding an internship during college and consequently finding a job after graduation is getting more difficult due to the intense competition, not only at ASU, but at every other college and university across the globe. The literature review showed that employers are looking for more from a potential candidate besides a degree and a good GPA (Grade Point Average). Employers are looking for well-developed leadership and soft skills (Dalessio, 1989). These attributes are not always learned in the classroom and many students are under the false impression that an engineering degree alone is enough to land them a job. The survey that was conducted proved that the more engineering-related extracurricular activities a student engages in, the greater the chance of finding an internship. Similarly, a linear relationship was also found between the number of activities involved in and number of interviews received. From the literature review, relevant experience is of utmost importance to many employers. Because of this, not receiving an internship throughout college greatly lessens a students’ success finding a job after college. The survey showed male students do far less extracurricular activities according to the survey compared to females. The males from the survey had a 51% percent success rate of finding an internship compared to the 71% success rate of females. As a Peer Career Coach at ASU, students come to me far too often and far too late in their academic career with empty resumes and lack of involvement. Each and every one of these students struggle heavily to find internships and eventually jobs. This problem can easily be addressed, but students must be aware that a high GPA in an engineering degree alone will not make them competitive in the job market.

ContributorsStorino, Siena Rose (Author) / Ganesh, Tirupalavanam (Thesis director) / Caolo, Jessica (Committee member) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
130859-Thumbnail Image.png
Description

This thesis proposes an extension of David Lewis's causal influence account of causation, providing a method to calculate the `degrees of causal influence.' By providing a quantitative approach to causal influence, I find that that the influence approach can assess statements that involve causal redundancies, allowing the assessor to attribute

This thesis proposes an extension of David Lewis's causal influence account of causation, providing a method to calculate the `degrees of causal influence.' By providing a quantitative approach to causal influence, I find that that the influence approach can assess statements that involve causal redundancies, allowing the assessor to attribute primary causal responsibility to the contending cause with a higher net influence value. The causal influence calculation also addresses criticisms towards Lewis's influence account, namely those involving `inert zones' of influence, the use of the term `might,' trumping versus symmetric overdetermination, and Lewis's clause requiring stepwise influence. This thesis also compares the results of causal influence in multiple toy cases including Two Rocks, both the asymmetric and symmetric variants, demonstrating that causal influence overcomes many of the core issues in Lewis's initial counterfactual account of causation. Using the asymmetric Two Rocks variant, this thesis also provides a detailed example of how to use the calculation and a discussion of the calculation's limitations. The main drawbacks of the quantitative method for causal influence seems to be the effort that it requires and issues in finding measurable qualities to compare the similarity/difference between possible worlds. Using the Two Rocks case, however, the causal influence calculation reaches the same conclusions as what Lewis suggests. A primary remaining issue is applying the calculation to instances of causation by omission, however this seems to only be a problem in using the equations rather than a problem within the idea of causal influence itself. Also, there may still be issues in justifying comparative overall similarity. However, this is an issue that both the counterfactual and influence accounts face.

ContributorsKha, Rachael Thuy-Trang (Author) / Watson, Jeffrey (Thesis director) / Botham, Thad (Committee member) / McElhoes, David (Committee member) / Historical, Philosophical & Religious Studies, Sch (Contributor) / Chemical Engineering Program (Contributor) / Economics Program in CLAS (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
166162-Thumbnail Image.png
Description

Speculative fiction and fantasy media have abundant power to portray alternative realities or imagined futures for minority groups. Buffy the Vampire Slayer, from the late 1990s-early 2000s, and Wynonna Earp, from the late 2010s, are two fantasy television shows that produce this often-progressive, impactful representation, particularly for lesbians and bisexual

Speculative fiction and fantasy media have abundant power to portray alternative realities or imagined futures for minority groups. Buffy the Vampire Slayer, from the late 1990s-early 2000s, and Wynonna Earp, from the late 2010s, are two fantasy television shows that produce this often-progressive, impactful representation, particularly for lesbians and bisexual people. Drawing on Queer and Monster Theories from Susan Stryker, Marilee Lindemann, Harry Benshoff, and Alexis Lothian, this thesis examines queer representation in these TV shows and how it contributes to the normalization of LGBTQ+ individuals whilst simultaneously honoring the shows’ queer fans. Normalizing non-cishetero genders and sexualities helps rewrite the narrative of LGBTQ+ people being considered “deviant” and threatening societal order; and holding true to queer roots of challenging social norms prevents the power of the queer community from being influenced by the pressures of compulsory heterosexuality.

ContributorsCardona, Lauren (Author) / Van Engen, Dagmar (Thesis director) / Mack, Robert (Committee member) / Barrett, The Honors College (Contributor) / Chemical Engineering Program (Contributor)
Created2022-05
165458-Thumbnail Image.png
Description

In 2019, the World Health Organization stated that climate change and air pollution is the greatest growing threat to humanity. With a world population of close to 8 billion people, the rate of population growth continues to increase nearly 1.05% each year. As the world population grows, carbon dioxide emissions

In 2019, the World Health Organization stated that climate change and air pollution is the greatest growing threat to humanity. With a world population of close to 8 billion people, the rate of population growth continues to increase nearly 1.05% each year. As the world population grows, carbon dioxide emissions and climate change continue to accelerate. By observing increasing concentrations of greenhouse gas emissions in the atmosphere, scientists have correlated that the Earth’s temperature is increasing at an average rate of 0.13 degrees Fahrenheit each decade. In an effort to mitigate and slow climate change engineers across the globe have been eagerly seeking solutions to fight this problem. A new form of carbon dioxide mitigation technology that has begun to gain traction in the last decade is known as direct air capture (DAC). Direct air capture works by removing excess atmospheric carbon dioxide from the air and repurposing it. The major challenge faced with DAC is not capturing the carbon dioxide but finding a useful way to reuse the post-capture carbon dioxide. As part of my undergraduate requirements, I was tasked to address this issue and create my own unique design for a DAC system. The design was to have three major goals: be 100% self-sufficient, have net zero carbon emissions, and successfully repurpose excess carbon dioxide into a sustainable and viable product. Arizona was chosen for the location of the system due to the large availability of sunlight. Additionally, the design was to utilize a protein rich hydrogen oxidizing bacteria (HOB) known as Cupriavidus Necator. By attaching a bioreactor to the DAC system, excess carbon dioxide will be directly converted into a dense protein biomass that will be used as food supplements. In addition, my system was designed to produce 1 ton (roughly 907.185 kg) of protein in a year. Lastly, by utilizing solar energy and an atmospheric water generator, the system will produce its own water and achieve the goal of being 100% self-sufficient.

ContributorsMacIsaac, Ian (Author) / Lin, Jerry (Thesis director) / Ovalle-Encinia, Oscar (Committee member) / Barrett, The Honors College (Contributor) / Chemical Engineering Program (Contributor) / Historical, Philosophical & Religious Studies, Sch (Contributor)
Created2022-05