Matching Items (295)
Description
Upon cooling a semicrystalline polymer from its amorphous melt state, it undergoes melt crystallization where organized microstructures develop through a process of nucleation and crystal growth. Understanding the crystallization kinetics of a semicrystalline thermoplastic is key to tuning crystallinity and microstructure, which play integral roles in the material’s final properties

Upon cooling a semicrystalline polymer from its amorphous melt state, it undergoes melt crystallization where organized microstructures develop through a process of nucleation and crystal growth. Understanding the crystallization kinetics of a semicrystalline thermoplastic is key to tuning crystallinity and microstructure, which play integral roles in the material’s final properties such as toughness, gas permeability, and degradation rate. Nonisothermal crystallization, in particular, has great technological relevance to polymer engineering processes such as injection molding, film blowing, and fiber spinning, all of which rely on fast cooling rates. Spectroscopic, scattering, calorimetric, and rheological techniques have been conventionally used for studying nonisothermal crystallization, but can be limited in their sensitivity, tunability, and availability. Our group has recently developed a fluorescence technique for sensing the melting transitions of semicrystalline thermoplastics by incorporating fluorescent probes into polymer matrices. Herein, this methodology has been extended to an in-situ study of nonisothermal melt crystallization by monitoring the T-dependent fluorescence intensity of the fluorophores incorporated into a polymer matrix. As crystals form upon cooling from the amorphous melt state, the intramolecular motions of fluorophores are restricted and thus their T-dependent fluorescence intensity data exhibit a stepwise increase during nonisothermal crystallization. The first derivative of the T-dependent fluorescence intensity data can provide insight into the onset, peak, and endset crystallization temperatures, all of which align reasonably well with conventional differential scanning calorimetry measurements. This facile, sensitive, and contact-free fluorescence technique can access faster cooling rates (up to ~100 oC min-1) than many other existing methods for nonisothermal crystallization studies, which is more relevant to industrial polymer processing conditions. Additionally, the fluorescence detection mechanism shows great sensitivity not only to the degree of crystallinity but also to the crystalline microstructure formed during nonisothermal crystallization. Furthermore, unique fluorescent labeling is expected to foster novel studies on the local crystallization within heterogeneous polymeric systems including blends, composites, and multilayer films. Such local crystallization studies are out of reach for most conventional techniques that measure spatially averaged properties. Overall, this nonisothermal crystallization study expands the capabilities of this novel fluorescence technique for advancing the field of semicrystalline thermoplastic design and processing.
ContributorsCabello, Maya (Author) / Jin, Kailong (Thesis director) / Nile, Gabriel (Committee member) / Barrett, The Honors College (Contributor) / Chemical Engineering Program (Contributor)
Created2022-05
Description

Utilizing DFT calculations, various substitutions on the AlPO-5 zeolite were screened for adsorption of common air molecules. Furthermore, free energy analyses using the Helmholtz free energy equation were performed to determine candidates for selective adsorption of one specific air molecule, and their operating temperature range. Through this study, it was

Utilizing DFT calculations, various substitutions on the AlPO-5 zeolite were screened for adsorption of common air molecules. Furthermore, free energy analyses using the Helmholtz free energy equation were performed to determine candidates for selective adsorption of one specific air molecule, and their operating temperature range. Through this study, it was found that Cerium- (92-542 K), Germanium- (69-370 K), Chromium- (35-293 K), and Praseodymium- (0-420 K) substituted AlPO-5 selectively adsorbs to O2 molecules for the given temperature ranges. In addition, Palladium-substituted AlPO-5 selectively adsorbs to CO within 430-755 K.

ContributorsIrudaya Pious Suresh, Enosh (Author) / Muhich, Christopher (Thesis director) / Emady, Heather (Committee member) / Barrett, The Honors College (Contributor) / Chemical Engineering Program (Contributor)
Created2022-05
Description

Rotary drums are tools used extensively in various prominent industries for their utility in heating and transporting particulate products. These processes are often inefficient and studies on heat transfer in rotary drums will reduce energy consumption as operating parameters are optimized. Research on this subject has been ongoing at ASU;

Rotary drums are tools used extensively in various prominent industries for their utility in heating and transporting particulate products. These processes are often inefficient and studies on heat transfer in rotary drums will reduce energy consumption as operating parameters are optimized. Research on this subject has been ongoing at ASU; however, the design of the rotary drum used in these studies is restrictive and experiments using radiation heat transfer have not been possible.<br/><br/>This study focuses on recounting the steps taken to upgrade the rotary drum setup and detailing the recommended procedure for experimental tests using radiant heat transfer upon completed construction of the new setup. To develop an improved rotary drum setup, flaws in the original design were analyzed and resolved. This process resulted in a redesigned drum heating system, an altered thinner drum, and a larger drum box. The recommended procedure for radiant heat transfer tests is focused on determining how particle size, drum fill level, and drum rotation rate impact the radiant heat transfer rate.

ContributorsMiller, Erik R (Author) / Emady, Heather (Thesis director) / Muhich, Christopher (Committee member) / Chemical Engineering Program (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description

The increased shift towards environmentalism has brought notable attention to a universal excessive plastic consumption and subsequent plastic overload in landfills. Among these plastics, polyethylene terephthalate, more commonly known as PET, constitutes a large percentage of the waste that ends up in landfills. Material and chemical/thermal methods for recycling are

The increased shift towards environmentalism has brought notable attention to a universal excessive plastic consumption and subsequent plastic overload in landfills. Among these plastics, polyethylene terephthalate, more commonly known as PET, constitutes a large percentage of the waste that ends up in landfills. Material and chemical/thermal methods for recycling are both costly, and inefficient, which necessitates a more sustainable and cheaper alternative. The current study aims at fulfilling that role through genetic engineering of Bacillus subtilis with integration of genes from LCC, Ideonella sakaiensis, and Bacillus subtilis. The plasmid construction was done through restriction cloning. A recombinant plasmid for the expression of LCC was constructed, and transformed into Escherichia coli. Future experiments for this study should include redesigning of primers, with possible combination of signal peptides with genes during construct design, and more advanced assays for effective outcomes.

ContributorsKalscheur, Bethany Ann (Author) / Varman, Arul (Thesis director) / Andino, Jean (Committee member) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description

Researchers John H. Falk and Lynn D. Dierking developed what they call the Contextual Model of Learning in their 2012 publication, The Museum Experience Revisited. This model emphasizes the significance of the visitor experience in the museum industry and is defined as three interconnected contexts that constitute a museum visitor’s

Researchers John H. Falk and Lynn D. Dierking developed what they call the Contextual Model of Learning in their 2012 publication, The Museum Experience Revisited. This model emphasizes the significance of the visitor experience in the museum industry and is defined as three interconnected contexts that constitute a museum visitor’s experience. These contexts are the personal context, the sociocultural context, and the physical context. Falk and Dierking argue that all three contexts must be properly acknowledged by the museum for a positive visitor experience. They also provide readers with several recommendations on effective design strategies that fit within the principles of the Contextual Model of Learning. In this analysis, these principles are related directly to museums today. The Field Museum in Chicago and The Children’s Museum of Phoenix are noted for having exceptional websites. The Royal Ontario Museum and the Asian Art Museum are mentioned for having engaging marketing strategies. The Black Country Living Museum in the United Kingdom and the Museum of Modern Art in New York are recognized for innovative social media use. The USS Midway Museum in San Diego and the Musical Instrument Museum in Phoenix are acknowledged for their excellent designs, media usage in exhibits, and accessibility options. The British Museum in London is mentioned for its virtual experiences and gift shop. The Metropolitan Museum of Art is also mentioned for its gift shop. The Arizona Science Center and the Children’s Museum of Indianapolis are commended for their programs. Finally, a brief discussion is done on STEAMtank, a museum experience in development at Arizona State University, and how the principles within the Contextual Model of Learning are being integrated in similar fashion to the other museums discussed.

ContributorsThayer, Dylan (Author) / Heller, Cheryl (Thesis director) / Peters, Abigail (Committee member) / Martin, Paul (Committee member) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description

Lignin is a naturally abundant source of aromatic carbon but is largely underutilized in industry because it is difficult to decompose. Under the current study we engineered Corynebacterium glutamicum for the depolymerization of lignin with the goal of using it as raw feed for the sustainable production of valuable chemicals.

Lignin is a naturally abundant source of aromatic carbon but is largely underutilized in industry because it is difficult to decompose. Under the current study we engineered Corynebacterium glutamicum for the depolymerization of lignin with the goal of using it as raw feed for the sustainable production of valuable chemicals. C. glutamicum is a standout candidate for the depolymerization and assimilation of lignin because of its performance as an industrial producer of amino acids, resistance to aromatic compounds in lignin, and low extracellular protease activity. Three different foreign and native ligninolytic enzymes were tested in combination with three signal peptides to assess lignin degradation efficacy. At this stage, six of the nine plasmid constructs have been constructed.

ContributorsEllis, Dylan Scott (Author) / Varman, Arul Mozhy (Thesis director) / Nannenga, Brent (Committee member) / Nowroozi, Farnaz (Committee member) / Chemical Engineering Program (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
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
Description

Chemistry has always played a foundational role in the synthesis of pharmaceuticals. With the rapid growth of the global population, the health and medical needs have also rapidly increased. In order to provide drugs capable of mediating symptoms and curing diseases, organic chemistry provides drug derivatives utilizing a limited number

Chemistry has always played a foundational role in the synthesis of pharmaceuticals. With the rapid growth of the global population, the health and medical needs have also rapidly increased. In order to provide drugs capable of mediating symptoms and curing diseases, organic chemistry provides drug derivatives utilizing a limited number of chemical building blocks and privileged structures. Of these limited building blocks, this project explores Late–stage C–H functionalization of (iso)quinolines using abundant metal catalysis in order to achieve site-selective molecular modification.

ContributorsPearson, Amanda (Author) / Ackerman–Biegasiewicz, Laura (Thesis director) / Biegasiewicz, Kyle (Committee member) / Gould, Ian (Committee member) / Barrett, The Honors College (Contributor) / Chemical Engineering Program (Contributor)
Created2022-05
Description

The outlying cities of Phoenix's West Metropolitan experienced rapid growth in the past ten years. This trend is only going to continue with an average expected growth of 449-891% between 2000 and 2035 (ADOT, 2012). Phoenix is not new to growth and has consistently seen swaths of people added to

The outlying cities of Phoenix's West Metropolitan experienced rapid growth in the past ten years. This trend is only going to continue with an average expected growth of 449-891% between 2000 and 2035 (ADOT, 2012). Phoenix is not new to growth and has consistently seen swaths of people added to its population. This raises the question of what happened to the people who lived in Phoenix's West Valley during this period of rapid change and growth in their communities? What are their stories and what do their stories reveal about the broader public history of change in Phoenix's West Valley? In consideration of these questions, the community oral histories of eight residents from the West Valley were collected to add historical nuance to the limited archival records available in the area. From this collection, the previous notion of "post-war boomtowns” describing Phoenix’s West Valley was revealed to be highly inaccurate and dismissive of the residents' experiences who lived and formed their lives there.

ContributorsGeiser, Samantha (Author) / Campanile, Isabella (Co-author) / Martinez Orozco, Rafael (Thesis director) / O'Flaherty, Katherine (Committee member) / Barrett, The Honors College (Contributor) / Chemical Engineering Program (Contributor) / School of Mathematical and Statistical Sciences (Contributor)
Created2022-05
Description
Sleep paralysis is when a person finds themselves in a state of conscious paralysis as they are falling asleep or waking up. It is often accompanied by shallowing breathing, visual and auditory hallucinations, and a sense of terror. Sleep paralysis has a rich folklore consisting of sleep demons,

Sleep paralysis is when a person finds themselves in a state of conscious paralysis as they are falling asleep or waking up. It is often accompanied by shallowing breathing, visual and auditory hallucinations, and a sense of terror. Sleep paralysis has a rich folklore consisting of sleep demons, spirits, and curses some of which are still told to children today. This thesis will explore a timeline of this folklore that involves modern day sleep paralysis, a history of sleep science, and how they collided resulting in the official diagnosis of sleep paralysis as a sleep disorder.
ContributorsBusselle, Olivia (Author) / Boyce-Jacino, Katherine (Thesis director) / Petrov, Megan (Committee member) / Barrett, The Honors College (Contributor) / Chemical Engineering Program (Contributor)
Created2022-05