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Title
THE GALACTIC NOVA RATE : ESTIMATES FROM ALL-SKY TIME DOMAIN SURVEYS
Creator
Kawash, Adam
Date
2022
Collection
Electronic Theses & Dissertations
Description
There is a significant discrepancy between recent predictions of the Milky Way classical novarate of ∼ 60 per year and the annual discovery rate of ∼ 10. Why the recovery fraction of these events is ∼ 15% even with large advancements to observational time domain astronomy remains largely unexplained. Because of the location of Earth within the Galaxy, discovering Galactic transients requires a large field of view. For the past few decades, observations from a network of amateur astronomers...
Show moreThere is a significant discrepancy between recent predictions of the Milky Way classical novarate of ∼ 60 per year and the annual discovery rate of ∼ 10. Why the recovery fraction of these events is ∼ 15% even with large advancements to observational time domain astronomy remains largely unexplained. Because of the location of Earth within the Galaxy, discovering Galactic transients requires a large field of view. For the past few decades, observations from a network of amateur astronomers were largely responsible for discovering classical novae, so the sky-coverage as a function of position and depth was difficult to model. Fortunately, in the past decade, many time domain surveys with fields of view that cover large areas of the sky have been commissioned, making the sky-coverage more well defined. To date, there are no Galactic nova rate predictions made using data from a time domain survey that is capable of observing the entire sky. In this thesis, the first estimate of the Galactic nova rate using observations from two all-sky surveys is made. The All-Sky Automated Survey for Supernovae (ASAS-SN) is the first survey to systematically observe the entire sky every night, providing unprecedented cadence of the sky for transients and variable stars. The space-based survey Gaia has a broad observing filter and a fine (∼ 0.1 arcsecond) pixel scale, so it is capable of detecting Galactic plane transients in crowded fields that are heavily affected by extinction. These are the only two all-sky surveys to report classical nova candidates, and they have contributed to marginally increasing the discovery rate of Galactic novae to 13 per year on average since 2017. In addition to the increase in discoveries, this thesis exploits the systematic observing patterns to estimate what fraction of the Galaxy’s novae these surveys detect. To make this estimate, I have constructed a statistical model of Galactic classical novae by utilizing the recently published models of stellar density and extinction of the Milky Way. Using ASAS-SN photometry, I measure the outburst amplitude of novae to be normally distributed with mean and standard deviation μ = 11.43 ± 0.25 mag and σ = 2.57 ± 0.20 mag, respectively. By using recently available all-sky 3D dust maps, I estimate that ∼ 50% of Galactic novae are hidden by extinction from being detected by ASAS-SN. Finally, I estimate that the recovery fraction of the global population of Galactic novae for ASAS-SN ≈ 33%, Gaia ≈ 42%, and a joint effort of the two surveys ≈ 54%, predicting that the Galactic nova rate is 26 ± 5 yr−1, significantly lower than recent estimates.
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Title
ELUCIDATING THE POTENTIAL ROLE OF ARYL HYDROCARBON RECEPTOR IN THE PATHOGENESIS OF CAMPYLOBACTER JEJUNI.
Creator
Ahmed, Husnain
Date
2022
Collection
Electronic Theses & Dissertations
Description
Campylobacter jejuni is a leading cause of human foodborne gastroenteritis in the US, with an incidence rate of 13.6 diagnosed cases per 100,000 individuals. The most frequent cause of C. jejuni infection in the US is the consumption of chicken contaminated during processing. Macrolide antibiotics such as azithromycin and ciprofloxacin are the drug of choice to treat C. jejuni infection in human populations. However, the over-use of antibiotics has led to the emergence of antimicrobial...
Show moreCampylobacter jejuni is a leading cause of human foodborne gastroenteritis in the US, with an incidence rate of 13.6 diagnosed cases per 100,000 individuals. The most frequent cause of C. jejuni infection in the US is the consumption of chicken contaminated during processing. Macrolide antibiotics such as azithromycin and ciprofloxacin are the drug of choice to treat C. jejuni infection in human populations. However, the over-use of antibiotics has led to the emergence of antimicrobial-resistant C. jejuni strains and reduced treatment efficacy. The development of antimicrobial resistance traits in C. jejuni isolates has augmented the need to develop innovative strategies to treat drug-resistant C. jejuni infections in human and animal populations.Members of the genus Lactobacillus are commonly used as probiotics, however the mechanisms by which they provide protective health effects remain elusive. In the first study, we described a novel mechanism by which L. murinus attenuates pro-inflammatory responses in the human intestinal epithelial cells. The results showed that L. murinus activates aryl hydrocarbon receptor (AHR) to decrease the secretion of IL-8 in response to exogenous stimulation by TNF-alpha in the human intestinal epithelial cells. Furthermore, activating the AHR with its defined ligand also reduced the secretion of IL-8 upon TNF-alpha stimulation. These results suggest that AHR can a novel target for inflammatory bowel disease (IBD) treatment. Furthermore, these results suggest that L. murinus can be a novel probiotic for treating IBD. In the 2nd study, we determined the effect of prophylactic inoculation of L. muirnus on the pathogenesis of C. jejuni in the BALB/c IL-10-/- mice. A total of 41 BALB/c IL-10-/- mice were used in this study. 11 mice were sham inoculated, 10 mice received only L. murinus, 10 mice received only C. jejuni, and 10 mice in the test group received both L. murinus and C. jejuni such that L. murinus was inoculated 32 days before C. jejuni infection. In addition, 30 days post-C. jejuni challenge mice were sacrificed and assessed for gut pathology. Fecal samples were also collected to access bacterial colonization levels in the gut through routine culture techniques and 16S sequence analysis. Both positive control group for C. jejuni and test groups mice developed severe colitis. 16S analysis of fecal DNA revealed that bacterial diversity in the test and positive control group for C. jejuni was significantly less (P<0.001) than in the Lactobacillus only and negative control group. These results suggest that prophylactic administration of L. murinus does not protect BALB/c IL-10-/- mice from developing disease following C. jejuni infection. Overall, this dissertation contains identification of a novel mechanism of action of L. murinus. The results provide insights for the identification of novel targets to treat C. jejuni disease without using antibiotics. This dissertation provides a basis for the future studies to further dissect the role of the AHR in the pathogenesis of C. jejuni.
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Title
ADVANCING ENGINEERED ENDOSYMBIONTS AS A PLATFORM TECHNOLOGY FOR THERAPEUTIC MACROPHAGE MODULATION
Creator
Madsen, Cody Scott
Date
2022
Collection
Electronic Theses & Dissertations
Description
This dissertation describes the construction of engineered endosymbionts (EES) as a platform technology for modulating macrophage function for therapeutic applications. Dr. Ashley Makela and I worked closely to advance the EES technology. Dr. Makela focused on the characterization of the EES ability to change macrophage function and I focused on developing the EES technology and working with Dr. Makela on characterization and using the EES in applications (Chapter 2 and 3). In Chapter 2,...
Show moreThis dissertation describes the construction of engineered endosymbionts (EES) as a platform technology for modulating macrophage function for therapeutic applications. Dr. Ashley Makela and I worked closely to advance the EES technology. Dr. Makela focused on the characterization of the EES ability to change macrophage function and I focused on developing the EES technology and working with Dr. Makela on characterization and using the EES in applications (Chapter 2 and 3). In Chapter 2, Bacillus subtilis was developed as a chassis organism for EES that escape phagosome destruction, reside in the cytoplasm of mammalian cells, and secrete proteins that are transported to the nucleus to impact host cell response and function. Two synthetic operons encoding either the mammalian transcription factors (TFs) Stat-1 and Klf6 or Klf4 and Gata-3 were recombined into the genome of B. subtilis expressing listeriolysin O (LLO) from Listeria monocytogenes and expressed from regulated promoters. Controlled expression of the mammalian proteins from B. subtilis LLO in the cytoplasm of J774A.1 macrophage/monocyte cells altered surface marker, cytokine and chemokine expression. Once the EES platform was developed and initially tested in vitro with a macrophage cell line, translating the EES to applications became the next step to understand the capacity of the new technology (Chapter 3). For increased translatability, the effect of the engineered B. subtilis LLO TF strains on murine bone marrow-derived macrophages (BMDMs) function was characterized. The TF strains shifted BMDM production of cytokines, chemokines and metabolic patterns. RNA-seq is still being analyzed to elucidate effects on gene expression. Furthermore, the ability of the B. subtilis LLO TF strains to alter the tumor microenvironment was characterized in a murine 4T1 orthotopic breast cancer model. The B. subtilis LLO strains altered the tumor microenvironment by promoting immune cell invasion, altering the functional metabolism of cells within the tumor, and causing tumor growth stabilization. Additionally, safety of this EES platform was observed as multiple doses at bacterial concentrations 100-fold more than other bacterial therapies were injected without affecting the health of mice. Yet, during the development and characterization of the EES, the sugar (D-mannose) that was used to induce transcription in the EES once inside the host cell was observed to significantly impact macrophage physiology which created additional complexity and was not ideal for in vivo applications. Accordingly, Emily Greeson and I worked on developing a mechanism for non-invasive localized control of gene expression in vivo. Emily Greeson engineered B. subtilis with temperature sensitive repressors (TSRs) and characterized this new genetic switch. I then coated B. subtilis with superparamagnetic iron oxide nanoparticles (SPIONs) which could be stimulated by an alternating magnetic field (AMF) to generate thermal energy. Chapter 4 discusses this new approach, and we investigated the ability of magnetic hyperthermia to regulate TSRs of bacterial transcription. The TSR, TlpA39, was derived from a Gram-negative bacterium, and used here for thermal control of reporter gene expression in Gram-positive B. subtilis. In vitro heating of B. subtilis with TlpA39 controlling bacterial luciferase expression, resulted in a 14.6-fold (12 hour; h) and 1.8-fold (1 h) increase in reporter transcripts with a 9-fold (12 h) and 11.1-fold (1 h) increase in bioluminescence. To develop magnetothermal control, B. subtilis cells were coated with three SPION variations which was confirmed by electron microscopy coupled with energy dispersive X-ray spectroscopy. Furthermore, using long duration AMF, we demonstrated magnetothermal induction of the TSRs in SPION-coated B. subtilis with a maximum of 4.6-fold increases in bioluminescence. Pairing TSRs with magnetothermal energy using SPIONs for localized heating with AMF can lead to improved EES transcriptional control. The research described in this dissertation demonstrates a multi-disciplinary approach towards developing a new modular technology to alter mammalian cell function with the specific focus on macrophages.
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Title
Efficient Distributed Algorithms : Better Theory and Communication Compression
Creator
LI, YAO
Date
2022
Collection
Electronic Theses & Dissertations
Description
Large-scale machine learning models are often trained by distributed algorithms over either centralized or decentralized networks. The former uses a central server to aggregate the information of local computing agents and broadcast the averaged parameters in a master-slave architecture. The latter considers a connected network formed by all agents. The information can only be exchanged with accessible neighbors with a mixing matrix of communication weights encoding the network's topology....
Show moreLarge-scale machine learning models are often trained by distributed algorithms over either centralized or decentralized networks. The former uses a central server to aggregate the information of local computing agents and broadcast the averaged parameters in a master-slave architecture. The latter considers a connected network formed by all agents. The information can only be exchanged with accessible neighbors with a mixing matrix of communication weights encoding the network's topology. Compared with centralized optimization, decentralization facilitates data privacy and reduces the communication burden of the single central agent due to model synchronization, but the connectivity of the communication network weakens the theoretical convergence complexity of the decentralized algorithms. Therefore, there are still gaps between decentralized and centralized algorithms in terms of convergence conditions and rates. In the first part of this dissertation, we consider two decentralized algorithms: EXTRA and NIDS, which both converge linearly with strongly convex objective functions and answer two questions regarding them. \textit{What are the optimal upper bounds for their stepsizes?} \textit{Do decentralized algorithms require more properties on the functions for linear convergence than centralized ones?} More specifically, we relax the required conditions for linear convergence of both algorithms. For EXTRA, we show that the stepsize is comparable to that of centralized algorithms. For NIDS, the upper bound of the stepsize is shown to be exactly the same as the centralized ones. In addition, we relax the requirement for the objective functions and the mixing matrices. We provide the linear convergence results for both algorithms under the weakest conditions.As the number of computing agents and the dimension of the model increase, the communication cost of parameter synchronization becomes the major obstacle to efficient learning. Communication compression techniques have exhibited great potential as an antidote to accelerate distributed machine learning by mitigating the communication bottleneck. In the rest of the dissertation, we propose compressed residual communication frameworks for both centralized and decentralized optimization and design different algorithms to achieve efficient communication. For centralized optimization, we propose DORE, a modified parallel stochastic gradient descent method with a bidirectional residual compression, to reduce over $95\%$ of the overall communication. Our theoretical analysis demonstrates that the proposed strategy has superior convergence properties for both strongly convex and nonconvex objective functions. Existing works mainly focus on smooth problems and compressing DGD-type algorithms for decentralized optimization. The class of smooth objective functions and the sublinear convergence rate under relatively strong assumptions limit these algorithms' application and practical performance. Motivated by primal-dual algorithms, we propose Prox-LEAD, a linear convergent decentralized algorithm with compression, to tackle strongly convex problems with a nonsmooth regularizer. Our theory describes the coupled dynamics of the inexact primal and dual update as well as compression error without assuming bounded gradients. The superiority of the proposed algorithm is demonstrated through the comparison with state-of-the-art algorithms in terms of convergence complexities and numerical experiments. Our algorithmic framework also generally enlightens the compressed communication on other primal-dual algorithms by reducing the impact of inexact iterations.
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Title
LEVEL 101 : A VIDEO GAME ABOUT VIDEO GAMES
Creator
Wigard, Justin Michael
Date
2022
Collection
Electronic Theses & Dissertations
Description
For my dissertation, I developed a serious game entitled Level 101: A Video Game About Video Games, a playable video game that explores, explains, and interrogates the video game in order to understand the medium through a methodology of play. In doing so, Level 101 puts disparate elements of Game Studies into practice due to its branching paths, introducing players to three distinct frameworks for understanding video games: 1) history, 2) design, and 3) theory. Each of these three branches...
Show moreFor my dissertation, I developed a serious game entitled Level 101: A Video Game About Video Games, a playable video game that explores, explains, and interrogates the video game in order to understand the medium through a methodology of play. In doing so, Level 101 puts disparate elements of Game Studies into practice due to its branching paths, introducing players to three distinct frameworks for understanding video games: 1) history, 2) design, and 3) theory. Each of these three branches features five stages designed to educate players about the video game medium, as well as encourage critical reflection on video games and the process of playing through them. The primary audiences are twofold: college instructors who will use and assign the video game as a lecture supplement, and college students who would play through the video game. This is accompanied by a traditional dissertation component that addresses several issues: 1) historical and cultural contextualization; 2) theoretical and methodological investments; 3) a summation of the project’s critical contributions; and 4) a reflection of the development process. Level 101 seeks to begin filling in a crucial and overlooked pedagogical gap in Game Studies through uniting play and learning via digital means, but only in conjunction with other aspects of traditional learning. As such, Level 101 sits at the intersection of three distinct areas of inquiry: Game Studies, Pedagogy, and Digital Humanities. By drawing not just from Game Studies, but from other corollaries in such disparate fields as comic studies, literary studies, film studies, among others, Level 101 also holds the potential for further experimentations with playable methods of academic engagement and alternative scholarship.
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Title
PRE-SERVICE TEACHERS AND AUTHOR IDENTITIES ON SOCIAL MEDIA : BEING AUTHORS AND TEACHING AUTHORING
Creator
Galvin, Sarah M.
Date
2022
Collection
Electronic Theses & Dissertations
Description
Social media are some of the most used digital composition tools by both youth and adults yet authoring in digital spaces remains undervalued and digital literacy education remains misaligned with workplace needs and expectations. Using a multiple case study design (n=3) to explore the authorship of pre-service English/ELA teachers on social media and how it impacts their composition instruction, this study forefronts social media as a critical space for authoring that should be considered in...
Show moreSocial media are some of the most used digital composition tools by both youth and adults yet authoring in digital spaces remains undervalued and digital literacy education remains misaligned with workplace needs and expectations. Using a multiple case study design (n=3) to explore the authorship of pre-service English/ELA teachers on social media and how it impacts their composition instruction, this study forefronts social media as a critical space for authoring that should be considered in the context of education. Multiple interview sessions and composition artifacts (e.g., social media posts, course assignments, creative writing) were used to gather stories of the pre-service teachers’ authorship experiences and their approaches to composition instruction. This study speaks to the need to reconsider what counts as valuable literacies; pre-service teachers’ frequent authoring on social media cannot be siloed away from the authorial identities they bring into their classrooms and their classroom instruction. Final analyses offer implications for future research at the intersection of authorship theory, social media, and pre-service teachers ’education, as well as implications for revised authorship theories and practical implications for supporting pre-service teachers as authors and composition instructors.
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Title
Eigenvector Continuation : Convergence and Emulators
Creator
Sarkar, Avik
Date
2022
Collection
Electronic Theses & Dissertations
Description
There has been a great interest in the scientific community in using machine learning to build emulators that can accurately predict scientific processes using only a fraction of the time needed for direct calculations. The computational advantage of emulators allows us to study processes that are beyond what is possible with direct calculations. Eigenvector continuation is one such emulation technique that was introduced recently. It is a variational method that finds the extremal...
Show moreThere has been a great interest in the scientific community in using machine learning to build emulators that can accurately predict scientific processes using only a fraction of the time needed for direct calculations. The computational advantage of emulators allows us to study processes that are beyond what is possible with direct calculations. Eigenvector continuation is one such emulation technique that was introduced recently. It is a variational method that finds the extremal eigenvalues and eigenvectors of a Hamiltonian matrix with one or more control parameters. The computational advantage comes from projecting the Hamiltonian onto a much smaller subspace of basis vectors corresponding to eigenvectors at some chosen training values of the control parameters. The method has proven to be very efficient and accurate for interpolating and extrapolating eigenvectors. In this work, we present a study on the error convergence properties of eigenvector continuation. With the insights we gain from learning the convergence properties, we then propose a self-learning algorithm to efficiently select training eigenvectors for eigenvector continuation. Self-learning is an active-learning process that relies on a fast estimate of the emulator error and a greedy local optimization algorithm that becomes more accurate as the emulator approximation improves. We show that self-learning emulators are highly efficient algorithms that offer both high speed and high accuracy, and it can be applied to any emulator that emulates the solution to a system of constraint equations, such as solutions of algebraic or transcendental equations, linear and nonlinear differential equations, and linear and nonlinear eigenvalue problems.
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Title
A MULTICASE STUDY OF THREE GRADUATE TEACHING ASSISTANTS PARTICIPATING IN THE MDISC TEACHING PROFESSIONAL DEVELOPMENT
Creator
Kuechle, Valentin Alexander Balthasar
Date
2022
Collection
Electronic Theses & Dissertations
Description
In this multicase study (Stake, 2005), I studied a semester-long online implementation of the “Mathematics Discourse in Secondary Classrooms” (Herbel-Eisenmann, Cirillo, et al., 2017) (MDISC) teaching professional development (T-PD)—slightly modified for the university context—which I offered to three mathematics-teaching graduate teaching assistants (GTAs) (i.e., Finnegan, Valeria, and Alice) who were no longer in their first year of teaching. I sought to understand: (a) How does the...
Show moreIn this multicase study (Stake, 2005), I studied a semester-long online implementation of the “Mathematics Discourse in Secondary Classrooms” (Herbel-Eisenmann, Cirillo, et al., 2017) (MDISC) teaching professional development (T-PD)—slightly modified for the university context—which I offered to three mathematics-teaching graduate teaching assistants (GTAs) (i.e., Finnegan, Valeria, and Alice) who were no longer in their first year of teaching. I sought to understand: (a) How does the classroom discourse change in each of the participant’s classes over the course of their participation in the MDISC T-PD?; and (b) How do participants talk about their use of the teacher discourse moves (TDMs) (e.g., Cirillo et al., 2014; Herbel-Eisenmann et al., 2013)? To analyze the change in classroom discourse, I studied two sets of classroom discourse dimensions: (a) the TDMs (i.e., waiting, inviting student participation, revoicing, asking students to revoice, probing a student’s thinking, and creating opportunities to engage with another’s reasoning), which were a central set of practical tools offered by the T-PD; and (b) student discourse dimensions drawn from the discourse dimensions of the “Equity QUantified In Participation” (EQUIP) tool (Reinholz & Shah, 2018).In line with a multicase approach, this study consists of one case report for each participant, with each report driven by an emic issue, as well as a multicase report thereafter in which the participants’ similarities and differences with respect to the research questions are explored. Finnegan, Valeria, and Alice’s respective emic issues were: (a) How can an instructor who wants students to participate in their class invite student participation?; (b) How does an instructor who weighs wielding her authority to engage students against respecting students’ agency (even if that agency is used to not participate) implement the TDMs?; and (c) How does an instructor who finds herself in a stage of “survival” (Beisiegel et al., 2019; Katz, 1972) implement and talk about the TDMs? Finnegan, who sought to invite student participation, especially took to TDMs that helped him do so: waiting (particularly wait time 1 [Rowe, 1986]), probing a student’s thinking, and inviting student participation via cold-calling. Valeria, who did not want to force students to do things, felt more comfortable implementing TDMs that relied more on what she was doing than on what students were doing. She mainly used waiting (particularly wait time 1), revoicing, and inviting student participation via inviting further responses. Last, Alice, who found herself in a stage of survival, continued using those TDMs that she was already familiar with, that is, waiting and revoicing. This study contributes to the emerging area of T-PD for GTAs beyond their first year of teaching. In addition, it offers a refinement of the TDMs and a detailed account of how and why participants used (or did not) each TDM. The TDM refinement includes: (a) a refinement of “waiting” that builds on work by Rowe (1986) and Ingram and Elliott (2016); (b) a refinement of “probing a student’s thinking” that distinguishes between two types of probing (i.e., to clarify a student’s turn or to go deeper with it) enacted in two ways (i.e., instructor- or student-centric) in response to student statements or questions; and (c) a refinement of “creating opportunities to engage with another’s reasoning” by distinguishing between five types of such engagement (i.e., adding to, anticipating, comparing to, evaluating, and understanding). Further, the participants’ uses for revoicing add to work on different uses of revoicing (e.g., Herbel-Eisenmann et al., 2009), and the participants’ hesitations about asking students to revoice provide insight into the challenges of learning to use this TDM.
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Title
Numerical Simulations of Plasmas in Galaxy Clusters
Creator
Glines, Forrest Wolfgang
Date
2022
Collection
Electronic Theses & Dissertations
Description
As the largest gravitationally bound objects in the universe, galaxy clusters are a unique probeof large scale cosmological structure. Determining the distribution of galaxy clusters and their virial masses may be key to constraining properties of dark energy and dark matter. Since 84% of a typical galaxy cluster’s mass is comprised of non-radiating dark matter, however, determining the virial mass of galaxy clusters depends on inference from the radiating baryonic matter. 84% of this...
Show moreAs the largest gravitationally bound objects in the universe, galaxy clusters are a unique probeof large scale cosmological structure. Determining the distribution of galaxy clusters and their virial masses may be key to constraining properties of dark energy and dark matter. Since 84% of a typical galaxy cluster’s mass is comprised of non-radiating dark matter, however, determining the virial mass of galaxy clusters depends on inference from the radiating baryonic matter. 84% of this baryonic matter is contained in the intracluster medium (ICM) – a hot, diffuse, magnetized plasma permeating the galaxy cluster. While the baryonic matter is the only emitter of observable electromagnetic emissions from galaxy clusters, the complex behavior of the ICM as a turbulent magnetized plasma makes constraining the virial mass of the cluster with observable signatures difficult. Numerical simulations are essential tools for advancing understanding of the ICM and for tying galaxy cluster observables to virial masses. The goal of this dissertation is to explore and enable simulations of galaxy clusters and magnetized plasmas via a number of different avenues.I first explore self-regulation of feedback from active galactic nuclei (AGN) preventing over-cooling in cool-core (CC) clusters – galaxy clusters with anomalously high central thermal emission which should cool on shorter timescales than they persist. In the idealized galaxy cluster simulations with a thermal abstraction of AGN feedback, we find that the thermal-only heating kernels we test are unable to offset cooling while maintaining a realistic structure, suggesting exploration of more complex AGN feedback mechanisms such as those including magnetic fields and turbulence.We then explore how kinetic and magnetic energy thermalizes in the ICM by studying decayingmagnetized turbulence with simulations of the magnetized compressible Taylor-Green vortex. Using a shell-to-shell energy transfer analysis, we find that the magnetic fields facilitate a significant amount of the energy flux that is not seen in hydrodynamic turbulence. Although the full cascade will not be directly captured in ICM simulations for the foreseeable future, higher resolution simulations enabled by larger computational resources can diminish such effects.Different novel many-core architectures have emerged in recent years on the way toward largersupercomputers in the exascale era. Performance portability is required to prevent repeated nontrivial refactoring of a code for different architectures. To address the need for a performance portable magnetohydrodynamics (MHD) code, we combined Athena++, an existing MHD CPU code, with Kokkos, a performance portable framework, into K-Athena to allow efficient simulations on multiple architectures using a single codebase. K-Athena has also inspired the Parthenon performance portable adaptive mesh refinement (AMR) framework. Using this framework, we developed the performance portable AMR MHD code AthenaPK.Galaxy clusters contain significant magnetic fields, although their origin and role is still underinvestigation. Numerical modeling is essential for the inference of their properties. One aspect is whether magnetic AGN feedback models can self-regulate. I present work-in-progress simulations with AthenaPK of magnetized galaxy clusters slated for exascale supercomputers later this year.With the higher resolutions enabled by exascale systems, galaxy cluster simulations with relativistic jet velocities will be possible. Robust methods for relativistic plasmas will be needed.With this goal, I present a discontinuous-Galerkin (DG) method for relativistic hydrodynamics. We include an exploration of different methods to recover the primitive variables from conserved variables, a new operator for enforcing a physically permissible conserved state, and numerous tests of the method. This method has been used at Sandia National Laboratories to study terrestrial plasmas and will inform relativistic MHD methods for AthenaPK.Finally, I cover the future directions of the work in this dissertation, including the many codesenabled by Parthenon, additions to the magnetized galaxy cluster simulations with AthenaPK, and the large body of projects at Los Alamos National Laboratory to explore binary black hole mergers embedded within AGN accretion disks as a possible formation channel of the massive black holes observed by LIGO. The work in this dissertation to develop performance portable plasma simulations will enable ground-breaking simulations for years to come.
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Title
Three Essays on Causes and Consequences of Violence and Conflict
Creator
Ayesh, Abubakr
Date
2022
Collection
Electronic Theses & Dissertations
Description
This dissertation revolves around the theme of violence, crime and conflict. It is an attempt at (a) improving the understanding of the causes of violence and crime, and (b) the consequences of violence and conflict. Specifically, the first chapter investigates if air pollution can be a contributor to crime, the second chapter looks at the labor market impacts of terrorism in non-war zones, and the last chapter tries to understand the human capital accumulation decisions of permanently...
Show moreThis dissertation revolves around the theme of violence, crime and conflict. It is an attempt at (a) improving the understanding of the causes of violence and crime, and (b) the consequences of violence and conflict. Specifically, the first chapter investigates if air pollution can be a contributor to crime, the second chapter looks at the labor market impacts of terrorism in non-war zones, and the last chapter tries to understand the human capital accumulation decisions of permanently displaced individuals.The first chapter looks at air pollution as a potential contributor to criminal activity. Using the seasonal variation in increase in air pollution --due to increased rice stubble burning-- in the Punjab province of Pakistan, I explore the relationship between air pollution and crime. I combine eight different sources of data and use an instrumental variable approach to estimate the causal impact of air pollution on crime. Air pollution increases both violent and non-violent crimes, but the increase in violent crimes is much more salient. A one standard deviation increase in seasonal variation in air pollution increases violent crime by at least 15 percent. Back of the envelope calculations suggest that the cost of increased crime due to air pollution are at least 5 million US dollars, but maybe as high as 600 million US dollars. One potential mechanism driving the estimates is the reduction in earnings for middle aged male individuals due to high air pollution. The results suggest that the social costs of air pollution are much wider than those previously considered. They also have significant implications for developing countries whose economies rely on agriculture. The second chapter of the dissertation looks at the impact of violence in non-war zones on incomes. A non-war zone does not have an active presence of the military, and it is not characterized by mass migration or shutting down of the economy. I use data from Pakistan on intermittent but sustained terrorist attacks for this purpose. After accounting for the intensity of the attacks, incomes reduce by about 2.5 percent on average due to terrorist attacks. However, the effect is almost twice in the same month in which a terrorist attack takes place in a district. The effects are more severe for low skilled members of the labor force as well as for relatively inexperienced members. The two potential channels driving this impact are the changes in employment compositions across different occupations and a reduction in the number of days worked. From a policy perspective, relief and welfare efforts targeted towards (a) the most vulnerable groups in the labor force and (b) the sectors of the economy directly affected by the violence seem to be the best possible response -instead of general aid aimed at overall rebuilding of the economy which is more relevant for a war or conflict zone. The last chapter considers the event of partition between India and Pakistan in 1947 that induced forced migration and permanent displacement of about 14.5 million people. I compare the educational outcomes of migrants and natives who were still in school going age when they were forced to migrate. I use a differences-in-differences approach. I also address the recent development in related literature on concerns related to identification, power, and bias in a differences-in-differences approach. I find that migrants are more likely to achieve certain educational milestones than their native counterparts. The results may be driven by the choices of older migrants pertaining to location and occupation. They also highlight the importance of an enabling and convenient environment for migrants which plays a crucial role in the pursuit of their educational goals.
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Title
DEVELOPMENT OF SCALABLE AND EXPEDITIOUS ADDITIVE MANUFACTURING PROCESS : A SOLUTION TO HIGH PRODUCTION ADDITIVE MANUFACTURING
Creator
Nguyen, Hoa Xuan
Date
2022
Collection
Electronic Theses & Dissertations
Description
For the past 40 years, metal additive manufacturing (AM) technologies with the capability of fabricating highly complex metal components with virtually no geometrical limitations, have enabled new opportunities in product designs and performance, while reducing total cost and shortening lead time, improving material efficiency and creating more sustainable products. A significant attention and interest of manufacturing industry lies on where metal AM can replace or improve production...
Show moreFor the past 40 years, metal additive manufacturing (AM) technologies with the capability of fabricating highly complex metal components with virtually no geometrical limitations, have enabled new opportunities in product designs and performance, while reducing total cost and shortening lead time, improving material efficiency and creating more sustainable products. A significant attention and interest of manufacturing industry lies on where metal AM can replace or improve production capability of traditional manufacturing (TM). Currently, the inherent difference between metal AM and TM leads to two separate manufacturing regions: metal AM is best suited for producing complex parts in small quantities while TM dominates high volume production. While metal AM processes are capable of providing individually designed products with a high level of details, TM processes with their fast, precise, and efficient production in combination with the long-established, quality assured, and widely implemented manufacturing techniques makes the competition incredibly difficult for AM when it comes to high volume production.As metal AM field evolves with an increasing demand in highly complex and customizable products, there is a critical need to fill in the gap in terms of production speed between metal AM and TM processes. This dissertation presents the development of the scalable and expeditious additive manufacturing (SEAM) process, which hybridizes binder jet printing and stereolithography principles, capitalizes on their advantages to produce a new metal AM processing route. The SEAM process is not only suitable for high production environment but also capable of fabricating components with excellent accuracy and resolution. Once fully developed, the process is well suited to bridge the productivity gap between metal AM and TM processes, making it an attractive candidate for further development and future commercialization as a solution to high production AM. After several proof-of-concepts, two fully functional prototypes were designed specifically for the processing of metal suspension, and subsequently constructed at Michigan State University. The relationships between cure depth and metal particle size for several metal suspensions were characterized, whose results were used to determine the appropriate processing conditions for each suspension. An innovative 2-step curing strategy was devised and applied to the printing process, which not only prevents sedimentation of metal powder particles in the print bed but also enables the fabrication of overhang geometry without supporting structures. Using the developed printing technique and processing parameters, 3D green objects were successfully fabricated for all the metallic alloys of interests. A series of experiments were subsequently carried out to characterize the thermal decomposition of the photopolymer, whose results were used to develop a debinding cycle that completely removes the binder while maintaining part structural integrity. The activated liquid phase sintering process of SS420 parts were optimized by utilizing analysis of variance, which arrived at an optimal sintering condition that produce parts with above 99.7 % relative density without any geometrical distortion. For Haynes 214, the supersolidus sintering behavior was characterized with respect to sintering temperature and holding time. The transient deformation behavior of the sintered parts with respect to holding time and temperature was also captured, whose results were capitalized to develop a 2-step sintering technique to produce fully dense parts with complete shape retention. The development of a numerical sintering model, the Olevsky-Skorohod model, was studied and implemented in a finite element analysis software, which can be used to aid the prediction of part density evolution and deformation during the sintering process.
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Title
Critical Entanglements : Animals in Victorian Fiction
Creator
Burnley, Sandy M.
Date
2022
Collection
Electronic Theses & Dissertations
Description
Critical Entanglements: Animals in Victorian Fiction draws on ecofeminist, posthumanist, and postcolonial methodologies in four canonical Victorian texts, Lewis Carroll’s Alice’s Adventures in Wonderland (1865), Olive Schreiner’s The Story of an African Farm (1883), Rudyard Kipling’s The Jungle Books (1894), and Bram Stoker’s Dracula (1897), to explore what Victorian authors may mean when they make environmental actors or more-than-human bodies speak, or more acutely, when they render them...
Show moreCritical Entanglements: Animals in Victorian Fiction draws on ecofeminist, posthumanist, and postcolonial methodologies in four canonical Victorian texts, Lewis Carroll’s Alice’s Adventures in Wonderland (1865), Olive Schreiner’s The Story of an African Farm (1883), Rudyard Kipling’s The Jungle Books (1894), and Bram Stoker’s Dracula (1897), to explore what Victorian authors may mean when they make environmental actors or more-than-human bodies speak, or more acutely, when they render them silent. Conventionally, such silence is often interpreted and misconstrued with more feminine, vulnerable, inferior, inanimate, and helpless characteristics, eliding these characters into mere metonyms or a praxis for humanity. Instead of reading these characters as more palatable metaphors for anthropocentric concerns, I propose to read them as, in fact, more-than-human beings. By centering their alterity and radical identity, I argue their presence invites new narratives to emerge that challenge the hegemony of humanistic models which burgeoned from Enlightenment legacies in the Victorian era. As mute, combative, and/or hostile challenges to the anthropomorphic assumptions of both writers and readers, these Victorian characters, I contend, combat the era’s sympathetic, humanist, androcentric, and liberal rhetoric, sometimes against what seems to be the explicit intentions of the authors. My research thus contributes to current scholarship on how Enlightenment theories of the human helped shaped the political and philosophical discourse that characterized nineteenth-century European society, especially within a masculine and Eurocentric context. Moreover, by applying an ecofeminist, posthumanist, and postcolonial lens to Victorian texts, I reveal the delimitations of liberalism and political thought, offer critiques to the incipient proto-posthumanist philosophies that were deployed to disguise the systemic oppression of Enlightenment legacies, and explore the andro- and anthropo- centric rhetoric that simultaneously perpetuated and challenged the definition of what makes one “human.” Finally, my intervention firmly stakes “posthumanist” resistance well within the Victorian era, thereby demonstrating how Victorians were already pushing back against heteronormative and humanist constructs as empire expanded into more foreign, ecocritical, intra-, and interspecies entanglements.
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Title
Hydrologic Variations Owing to Snowmelt Changes in the Mid Latitudes
Creator
Ford, Chanse M.
Date
2022
Collection
Electronic Theses & Dissertations
Description
Snowmelt is a critical hydrologic process in high latitude, non-alpine settings. The water stored in seasonal snowpacks melts in the spring months leading to increased spring streamflow and creating shallow groundwater recharge that helps sustain streams throughout the year from the contributions of baseflow. Many regions across the globe have experienced changes to snowpack dynamics and melt patterns due to increased winter temperatures resulting from global climate change. Currently, most...
Show moreSnowmelt is a critical hydrologic process in high latitude, non-alpine settings. The water stored in seasonal snowpacks melts in the spring months leading to increased spring streamflow and creating shallow groundwater recharge that helps sustain streams throughout the year from the contributions of baseflow. Many regions across the globe have experienced changes to snowpack dynamics and melt patterns due to increased winter temperatures resulting from global climate change. Currently, most of the research into the changing snowmelt hydrology has been focused on mountainous regions where snowpacks make up larger portions of those regions’ annual water budget. There is little research in these mid-latitude, non-alpine areas and the available research focuses on small areas or examines only one component of the hydrologic system.These understudied regions that receive seasonal snowfall require more thorough examination as changes to winter and spring snow can have negative societal consequences, especially in one of the world’s largest freshwater reservoirs of the Great Lakes. This dissertation contributes to the scientific knowledgebase regarding snowmelt dynamics in non-alpine settings. Novel statistical analyses are utilized to assess the amount of change to winter temperatures and the effects on snowmelt hydrology across spatial scales and decades of observational data. The results from these analyses are then used as a lens to simulate the landscape hydrology to quantify changes to shallow groundwater recharge, which is difficult to assess from empirical data alone. These findings also lead to an examination of the potential economic effects resulting from changes to the snowpack. Chapter 1 lays the groundwork for this dissertation by describing the relevance of the research and gives a brief overview of the different components. The foundational methodology is developed in Chapter 2, where a combination of observed physical data and outputs from several snow and precipitation models are used to classify winters in Michigan from 2003-2017 as warm or cool and quantify the hydrologic changes in those different winter types. The results show warmer winters had less overall snow, which melted earlier contributing to earlier and lower spring stream flows and increased net recharge of groundwater. Chapter 3 then takes this methodology and applies it to the entire eastern portion of the United States that receives seasonal snow from 1960-2019, with results similar to the preceding chapter, and demonstrating that these snow hydrology changes are not limited to Michigan or to the more recent decades. These findings then culminate in Chapter 4, where the Landscape Hydrology Model simulates the snowpack, surface flows and groundwater recharge in Michigan from 2000-2019. These fully distributed simulations show the decreased snow and periodic melting in warm winters has led to increased groundwater recharge and decreased surface flows. Chapter 5 concludes this dissertation by examining the downhill ski industry in Michigan using industry statistics and operational data from the Shanty Creek Resorts, describing the potential economic challenges in a warming future.
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Title
“PALABRA EMPEÑADA” : LA CONFIGURACIÓN INTELECTUAL DE GABRIELA MISTRAL A TRAVÉS DE SUS CARTAS, 1914-1957
Creator
Romero, Lau
Date
2022
Collection
Electronic Theses & Dissertations
Description
Gabriela Mistral (1889 – 1957) fue la primera mujer latinoamericana en obtener el Premio Nobel de Literatura, en 1945. Su reconocimiento como una fue tardío en su país natal, Chile, donde recibió el Premio Nacional de Literatura en 1951. Esta tesis investiga la correspondencia privada de Gabriela Mistral durante el período 1914 a 1957 para buscar otra explicación al fenómeno mistraliano fuera de su innegable talento. En otras palabras, esta investigación se centra en aquellas estrategias que...
Show moreGabriela Mistral (1889 – 1957) fue la primera mujer latinoamericana en obtener el Premio Nobel de Literatura, en 1945. Su reconocimiento como una fue tardío en su país natal, Chile, donde recibió el Premio Nacional de Literatura en 1951. Esta tesis investiga la correspondencia privada de Gabriela Mistral durante el período 1914 a 1957 para buscar otra explicación al fenómeno mistraliano fuera de su innegable talento. En otras palabras, esta investigación se centra en aquellas estrategias que la escritora despliega dentro del campo cultural tanto chileno como internacional (Pierre Bourdieu 1990; Toril Moi 1999; Gonzalo Catalán 1985) para asegurar su sitio dentro del mismo, expandir sus redes intelectuales y afectivas, y proteger su continuidad a través de la obtención de capital simbólico. La organización de la tesis, compuesta en cuatro capítulos, gira en torno a “nudos” en los cuales la trayectoria profesional de Mistral –y su capital acumulado– se pone en riesgo y/o se refuerzan a través del establecimiento de alianzas, amistades y favores. De allí también que la hipótesis principal se organice en torno a la “palabra empeñada”, como moneda de intercambio que posibilita no sólo diversas performances por parte de la autora, sino también por parte de sus interlocutores.
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Title
Ferromagnetic and Ferrimagnetic Materials as Josephson Junction Barriers
Creator
Madden, Alexander Edward
Date
2022
Collection
Electronic Theses & Dissertations
Description
In this dissertation we will show experimental results on different magnetic materialsas Josephson junction barriers. Previous work by our group has shown that a Josephson junction with two magnetic layers can be engineered to allow controllable switching between a ‘0’ state and a ‘π’ state, with applications in cryogenic computing. First, that work is expanded on to show that a different combination of Ni and NiFe thicknesses can also support that 0-π switching, allowing a preliminary phase...
Show moreIn this dissertation we will show experimental results on different magnetic materialsas Josephson junction barriers. Previous work by our group has shown that a Josephson junction with two magnetic layers can be engineered to allow controllable switching between a ‘0’ state and a ‘π’ state, with applications in cryogenic computing. First, that work is expanded on to show that a different combination of Ni and NiFe thicknesses can also support that 0-π switching, allowing a preliminary phase diagram of Ni and NiFe thicknesses to be outlined. Those measurements are done using a low-inductance symmetric SQUID to simplify the data analysis compared to previous experiments. We also explore other magnetic materials beyond Ni and NiFe. Fe is studied as a hard layer candidate and we show that while it does have desirable magnetic properties, the critical current of the junction is greatly reduced compared to when using Ni. We also study the rare-earth transition metal ferrimagnet CoGd. This alloy can be a compensated ferrimagnet with zero net magnetization while still supporting a spin-polarized transport current. We study the relationship between temperature, thickness, and concentra- tion needed to grow compensated films of nanometer-scale thicknesses. We present transport data on Josephson junctions with a CoGd barrier showing the 0-π transition characteristic of a ferromagnetic junction despite the near-zero magnetization.
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Title
Three Essays on Labor Market Regulation in the American Construction Industry
Creator
Hinkel, Matthew Phillip
Date
2022
Collection
Electronic Theses & Dissertations
Description
This three-article dissertation focuses on labor market regulation in the American construction industry.
Title
Sparse Large-Scale Multi-Objective Optimization for Climate-Smart Agricultural Innovation
Creator
Kropp, Ian Meyer
Date
2022
Collection
Electronic Theses & Dissertations
Description
The challenge of our generation is to produce enough food to feed the present and future global population. This is no simple task, as the world population is expanding and becoming more affluent, and conventional agriculture often degrades the environment. Without a healthy and functional environment, agriculture as we know it will fail. Therefore, we must equally balance our broad goals of sustainability and food production as a single system. Multi-objective optimization, algorithms that...
Show moreThe challenge of our generation is to produce enough food to feed the present and future global population. This is no simple task, as the world population is expanding and becoming more affluent, and conventional agriculture often degrades the environment. Without a healthy and functional environment, agriculture as we know it will fail. Therefore, we must equally balance our broad goals of sustainability and food production as a single system. Multi-objective optimization, algorithms that search for solutions to complex problems that contain conflicting objectives, is an effective tool for balancing these two goals. In this dissertation, we apply multi-objective optimization to find optimal management practices for irrigating and fertilizing corn. There are two areas for improvement in multi-objective optimization of corn management: existing methods run burdensomely slow and do not account for the uncertainty of weather. Improving run-time and optimizing in the face of weather uncertainty are the two goals of this dissertation. We address these goals with four novel methodologies that advance the fields of biosystems & agricultural engineering, as well as computer science engineering. In the first study, we address the first goal by drastically improving the performance of evolutionary multi-objective algorithms for sparse large-scale optimization problems. Sparse optimization, such as irrigation and nutrient management, are problems whose optimal solutions are mostly zero. Our novel algorithm, called sparse population sampling (SPS), integrates with and improves all population-based algorithms over almost all test scenarios. SPS, when used with NSGA-II, was able to outperform the existing state-of-the-art algorithms with the most complex of sparse large-scale optimization problems (i.e., 2,500 or more decision variables). The second study addressed the second goal by optimizing common management practices in a study site in Cass County, Michigan, for all climate scenarios. This methodology, which relied on SPS from the first goal, implements the concept of innovization in agriculture. In our innovization framework, 30 years of management practices were optimized against observed weather data, which in turn was compared to common practices in Cass County, Michigan. The differences between the optimal solutions and common practices were transformed into simple recommendations for farmers to apply during future growing seasons. Our recommendations drastically increased yields under 420 validation scenarios with no impact on nitrogen leaching. The third study further improves the performance of sparse large-scale optimization. Where SPS was a single component of a population-based algorithm, our proposed method, S-NSGA-II, is a novel and complete evolutionary algorithm for sparse large-scale optimization problems. Our algorithm outperforms or performs as well as other contemporary sparse large-scale optimization algorithms, especially in problems with more than 800 decision variables. This enhanced convergence will further improve multi-objective optimization in agriculture. Our final study, which addresses the second goal, takes a different approach to optimizing agricultural systems in the face of climate uncertainty. In this study, we use stochastic weather to quantify risk in optimization. In this way, farmers can choose between optimal management decisions with full understanding of the risks involved in every management decision.
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Title
REPRESENTACIONES DE LA CORRUPCIÓN Y LA VIOLENCIA DE ESTADO EN MÉXICO A TRAVÉS DE LA LITERATURA, LA MÚSICA Y EL CINE
Creator
Badillo Carlos, José Adrián
Date
2022
Collection
Electronic Theses & Dissertations
Description
Esta disertación examina las representaciones de la violencia y la corrupción del Estado en México mediante el análisis de obras literarias, musicales y cinematográficas desde principios de la década de 1960 hasta la actualidad. El enfoque de este proyecto es analizar cómo la literatura y las producciones culturales han respondido ante el papel que ha desempeñado el Estado mexicano en eventos históricos caracterizados por la violencia y la corrupción. Este proyecto inicia con la Masacre de...
Show moreEsta disertación examina las representaciones de la violencia y la corrupción del Estado en México mediante el análisis de obras literarias, musicales y cinematográficas desde principios de la década de 1960 hasta la actualidad. El enfoque de este proyecto es analizar cómo la literatura y las producciones culturales han respondido ante el papel que ha desempeñado el Estado mexicano en eventos históricos caracterizados por la violencia y la corrupción. Este proyecto inicia con la Masacre de Tlatelolco ocurrida en 1968 en la Ciudad de México. Por medio de la obra Regina, dos de octubre no se olvida (1988) de Antonio Velazco Piña se explora el intento del autor por recuperar una memoria histórica y se analiza también las representaciones de la violencia de Estado en contra del movimiento estudiantil en 1968 y los efectos sociales, políticos y culturales que esto genera en la década de los setentas. A través de obras literarias como El amante de Janis Joplin (2001) de Elmer Mendoza y Trabajos del reino (2004) de Yuri Herrera, este trabajo analiza las representaciones ficticias de la violencia de Estado y el desarrollo del narcotráfico en la década de los setentas, haciendo un énfasis en cómo se legitima y se representa la violencia subjetiva, sistémica y cultural. Desde el ámbito musical, este proyecto también analiza las representaciones de la violencia a través de géneros musicales como el rock y los narcocorridos. A pesar del intento de censura por parte del Estado, ambos géneros musicales han funcionado como una vía de expresión popular para proponer una contra narrativa del discurso oficial al igual que para protestar los sistemas de corrupción y violencia. Estas representaciones se profundizan aún más en el cine mexicano a partir del cambio de gobierno ocurrido en el 2000. Por medio de La ley de Herodes (1999) y El infierno (2010) de Luis Estrada, este proyecto presenta un análisis de las representaciones de la violencia y la corrupción desde una perspectiva satírica. El objetivo de este acercamiento es analizar los efectos de comicidad y reflexión que genera la sátira al abordar representaciones de violencia, corrupción y narcotráfico.
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Title
BLACK RAMS AND UNRULY JADES : READING ANIMALS IN THE LANDSCAPE OF RENAISSANCE CULTURAL GEOGRAPHY
Creator
Thurston, Jonathan W.
Date
2022
Collection
Electronic Theses & Dissertations
Description
From King of Tars to Volpone, animals frequently coded for cultural difference, whether that “entailed” race, ethnicity, nationality, or religion. And, ritually, scholars have noted that this correlation exists. Regarding the Middle Ages, Peggy McCracken writes in In the Skin of a Beast about how animal “society” was seen as a 1:1 mirror of human society and had similar cultural differences of its own. But, while many scholars note that animals appear when discussing representations of race...
Show moreFrom King of Tars to Volpone, animals frequently coded for cultural difference, whether that “entailed” race, ethnicity, nationality, or religion. And, ritually, scholars have noted that this correlation exists. Regarding the Middle Ages, Peggy McCracken writes in In the Skin of a Beast about how animal “society” was seen as a 1:1 mirror of human society and had similar cultural differences of its own. But, while many scholars note that animals appear when discussing representations of race and cultural difference, a visible gap remains: no one has discussed significantly the crossover of animals and cultural geography in premodern texts or even what that crossover signifies.My dissertation, Black Rams and Unruly Jades: Reading Animals in the Landscape of Renaissance Cultural Geography seeks to address that gap. With a combination of case studies and literary surveys, I track multiple ways that reading animals into cultural geography significantly alters our interpretation of many of the period texts. Just as Kim Hall works to understand a rhetorical dichotomy of “fair”/”dark” in terms of a contemporary racial discourse and Ian J. Smith reads literary instances of Others’ “barbarism” in the construction of cultural difference, I show how the socially constructed image of animals in the Renaissance informed contemporary understandings of cultural geography as evident in primary literature. I link primary dramatic works to contemporary animal discourse, often in the form of husbandry manuals, encyclopediae, and manége treatises. This historicist lens allows for the argument that contemporary knowledge of animal-human interactions informed these animal representations of human difference at the time. The first chapter examines Shakespeare’s Othello in terms of its animal-racial imagery. As Iago constantly refers to people as different animals, he iterates a social hierarchy of cultural difference through these animals. Each species reference calls to contemporary knowledge of the animal world and informs our reading of the play by providing additional layers of meaning based on the specific species referenced. Chapter two moves into English drama, starting with the Christopher Marlowe play, Tamburlaine the Great. The chapter starts with a longer survey of Renaissance Turk Plays to show the archetypes the Turk could hold in these narratives as well as the frequent animal connections that appeared in rhetoric around the Turk. This survey works at a macro scale, revealing the sheer volume of English drama that centered on the Turk and the English fascination with the exotic. The third chapter focuses on Lust’s Dominion and the way that characters give animal appellations to other characters. The chapter starts with background and synopsis of Dekker’s play and then constructs a theoretical framework for the chapter, claiming that naming a person an animal in the Renaissance responds to a rhetoric of cultural difference. The chapter ultimately argues that understanding the cultural significance of different animal species at the time informs our reading of the characters’ understanding of self and other in Lust’s Dominion. The final major chapter reads The Tempest alongside early colonial American texts, comparing descriptions of indigenous fauna to the island nature in the play. This ultimately works to paint Caliban as an indigenous person who is animalized in ways similar to indigenous Americans. The aspects of animal control and domestication play into the civilized-wild dichotomy here, specifically in fish management.
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Title
Understanding adhesion to monitor and control environmental processes : From virus detection to membrane fouling mitigation
Creator
Wang, Xunhao
Date
2022
Collection
Electronic Theses & Dissertations
Description
Adhesion is a physicochemical process of great importance for various environmental engineering technologies including those that are employed in water treatment facilities Understanding adhesion is the key to elucidating separation mechanisms in unit processes and operations such as flocculation, granular media filtration, membrane separation. The likelihood of adhesion can be quantified in terms of the interfacial energy of interaction between two objects. The first part of this...
Show moreAdhesion is a physicochemical process of great importance for various environmental engineering technologies including those that are employed in water treatment facilities Understanding adhesion is the key to elucidating separation mechanisms in unit processes and operations such as flocculation, granular media filtration, membrane separation. The likelihood of adhesion can be quantified in terms of the interfacial energy of interaction between two objects. The first part of this dissertation is devoted to the study of virus adhesion to surfaces commonly encountered in various indoor settings. Fomites are inanimate surfaces, which can transfer the pathogens to a new human host. Fomite-based transfer is an important pathway of virus transmission, along with direct contact and transmission through aerosols. The study of fomites has traditionally focused on determining whether there is presence of specific pathogenic organisms. In addition to detecting genetic material and viable microbes on fomite surfaces, it is also important to understand the underlying mechanism of virus adhesion and factors that affect the likelihood of transmission between fomites and humans. In this dissertation, Quartz Crystal Microbalance with Dissipation monitoring (QCM-D) is employed to quantify virus attachment to fomites. XDLVO modeling is applied to predict the virus-fomites interactions. Virion size, surface charge and surface energy components as well as surface charge and surface energy components of various fomites were measured and used as inputs to the XDLVO model.The second part of this dissertation describes the study of membrane filter aging due to membrane’s intermittent exposure to foulants and cleaning agents. This study explores how the surface chemistry of polyvinylidene fluoride (PVDF) membranes evolves in challenge tests with humic acid (HA) fouling and sodium hypochlorite (NaClO) employed as a model foulant and cleaning agent, respectively. The evolution of physicochemical properties of the ageing membranes is characterized based on surface energy calculations. The results point to the formation of a chemically irreversible layer of foulants that is conditioned by consecutive exposures to foulants and is comprised of the adsorbed foulant fraction that is hard to oxidize further.
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