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Title: EXPERIMENTAL ANALYSIS AND MODEL DEVELOPMENT OF DUAL MODE, TURBULENT JET IGNITION (DM-TJI) ENGINE OPERATING WITH GASOLINE AND ALTERNATIVE FUELS
Creator: Ayele, Yidnekachew Messele
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Gasoline fuel is the most convenient energy source for light-duty vehicles in energy density and refueling time. However, the emission regulations for internal combustion engines force the industry to exploit innovative combustion technologies. The spark-ignition engine was forced to be cleaner and more efficient, changing from regular combustion engines to a more advanced internal combustion engine and electrification. The current scenario shows that automotive companies and researchers are...
Show moreGasoline fuel is the most convenient energy source for light-duty vehicles in energy density and refueling time. However, the emission regulations for internal combustion engines force the industry to exploit innovative combustion technologies. The spark-ignition engine was forced to be cleaner and more efficient, changing from regular combustion engines to a more advanced internal combustion engine and electrification. The current scenario shows that automotive companies and researchers are exploring hybrid powertrains with advanced internal combustion engine technologies with electrification or pure electric vehicles. The Dual Mode, Turbulent Jet Ignition (DM-TJI) system is one of the promising advanced combustion systems, powered by active air/fuel scavenging pre-chamber ignition systems. The distributed ignition sites created by the pre-chamber flames improve the combustion engine's efficiency, simultaneously mitigating combustion knock at a high engine compression ratio and enabling lean-burn or high level of external EGR dilution operation. This study analyzes the performance of a single-cylinder DM-TJI metal engine with gasoline and alternative fuels. The first part of the study presents the experimental investigations on three pre-chamber nozzle orifice diameters at various engine speeds and 10 bar engine load. The combustion parameters for each tested orifice diameter are presented for the incremental engine speeds. A numerical analysis was conducted using the GT-Power model simulation tool to support the experimental result. The DM-TJI engine's maximum gross indicated efficiency was examined and found to be 44.56%, with a higher EGR dilution rate of 45%. This orifice diameter study reported on the first published results of the desertion. Additional experimental data were collected for the selected orifice diameter at a wide range of engine operating test matrices. A predictive engine model was introduced with experimental data validation. The experimental data and predictive model generated the engine performance and fuel map for a real-world fuel economy study. Conventional and hybrid powertrain vehicles were developed with GT-Suite commercial software. Each powertrain model was calibrated in terms of components (battery, electric motors) capacity, internal combustion engine operative points, energy management strategy, and gear ratios with chassis dynamometer measured data of the vehicle drive cycle. A selected U.S. Environmental Protection Agency (EPA) driving schedule was implemented on the GT-Suite powertrain. The DM-TJI engine drive cycle fuel economy is compared to an industry-based conventional vehicle with the same powertrain except for the engine map. The results show the DM-TJI engine fuel economy improvement between 10.5%-17.29% and CO2 emissions reductions between 9.51%-14.75% for the selected driving schedule. Mild and parallel hybrid powertrain further improve the fuel economy by 9.23% and 29.88%, respectively, compared to the conventional powertrain of the DM-TJI engine. The CO2 emission was reduced by 23%. Finally, the single-cylinder DM-TJI metal engine performance under different alternative fuels was studied. An experimental test was carried out at stoichiometric conditions with different fuels, engine speed, engine load, and EGR dilution rates. Compared to gasoline fuel, E80 ethanol blend fuel produces 4.47% less CO2 and 25.75% less CO emission, and methane fuel produces 27.91% less CO2 and 57.85% less CO emission. E80 ethanol blend has the highest indicated efficiency of 45.61% with 45% EGR dilution. Methane fuel has a maximum indicated efficiency of 45.03% with 38.5% EGR dilution.
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Title: Sustainable Public Place Development with Community Participant Process : A Case Study of Belle Isle Park, MI
Creator: Guminik, Bridget
Date: 2022
Collection: Electronic Theses & Dissertations
Description: There are many positive influences from greenspaces which are even more crucial in large urban cities such as Detroit, Michigan. The abandoned area of the old Belle Isle Park Zoo has been the subject of numerous redevelopment proposals. However, there is a gap in what designers have done and what this research proposes, which is that previous designs lacked community engagement. The purpose of this study is to demonstrate the importance and value in including community engagement into design...
Show moreThere are many positive influences from greenspaces which are even more crucial in large urban cities such as Detroit, Michigan. The abandoned area of the old Belle Isle Park Zoo has been the subject of numerous redevelopment proposals. However, there is a gap in what designers have done and what this research proposes, which is that previous designs lacked community engagement. The purpose of this study is to demonstrate the importance and value in including community engagement into design choices. With a series of public workshops with stakeholders, landscape performance research has been adopted to assess the impact of the final design proposal. The success of a final design after community engagement aims to promote the use of community engagement in design as a beneficial and necessary factor when installing public space developments. The study will utilize the abandoned zoo space in Belle Isle Park to demonstrate that the community will benefit more from having input in what changes are made to their own community spaces while still allowing the designers room to implement environmental and socioeconomic beneficial tactics.
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Title: TEACHERS’ BELIEFS, PERCEPTIONS, EXPERIENCES, AND STRATEGIES IN TEACHING AND ENGAGING MULTILINGUAL LEARNERS IN MATHEMATICS CLASSROOMS
Creator: Kursav, Merve Nur
Date: 2022
Collection: Electronic Theses & Dissertations
Description: The number of Multilingual Learners (MLs) enrolled in U.S. schools increased from 8.1% of the total student population to more than 10% between the 2000-2001 school year and the 2016-2017 school year (NCELA, 2016; U.S. Dept. of Education, NCES, 2020). Like all learners, MLs need support to ensure their engagement in mathematics classrooms (Kena et al., 2015; Silva & Kucer, 2016). While the number of MLs has been increasing, there has been limited research about how teachers support these...
Show moreThe number of Multilingual Learners (MLs) enrolled in U.S. schools increased from 8.1% of the total student population to more than 10% between the 2000-2001 school year and the 2016-2017 school year (NCELA, 2016; U.S. Dept. of Education, NCES, 2020). Like all learners, MLs need support to ensure their engagement in mathematics classrooms (Kena et al., 2015; Silva & Kucer, 2016). While the number of MLs has been increasing, there has been limited research about how teachers support these students’ engagement in content area classrooms (Hos, 2016). A notable paucity of studies focuses specifically on mathematics teachers’ experiences supporting MLs’ learning and engagement in mathematics classrooms (Warren et al., 2014). This study investigated mathematics teachers' beliefs, perceptions, experiences, and strategies in teaching and engaging MLs in 6th -12th grade mathematics classrooms. The dissertation study contributes to the field of mathematics education by providing practical and theoretical implications.This dissertation is built on an extensive review of the relevant literature about 6th-12th-grade mathematics teachers’ beliefs, perceptions, and experiences in teaching and engaging MLs in the mathematics classroom. I used a combination of Teacher Cognition (TC) and Culturally Responsive Teaching (CRT) as the theoretical framework. Mixed methods were used, and data were collected in two phases: (1) quantitative data (i.e., adapted survey using Karabenick and Noda’s (2004) survey and Rhodes’s (2017) CRT survey) and (2) qualitative data (i.e., teacher interviews). Results revealed that teachers frequently used appropriate materials, instructional resources, standards, objectives, scaffolding strategies (e.g., grouping, pacing, wait time, transparency in teaching, comprehensible input), and assessment tools to support MLs’ learning and engagement in the mathematics classroom. Data sources clearly illustrated that teachers strongly agreed they were comfortable with having MLs in their classroom and were willing to support MLs in learning mathematics by boosting their engagement. The results also showed that teachers needed to (1) learn and design strategies for academic support of MLs, (2) learn about the systematic school and district resources available to support for MLs’ identification and placement; (3) learn about district and school-level supports available at the administrator level; (4) make data-driven decisions about curriculum and instruction for MLs; (5) have more willingness to work with MLs; (6) have professional development and support for culturally responsive teaching and MLs' learning and engagement; (7) notice their beliefs about language acquisition (bilingualism and translanguaging); (8) establish inclusion; (9) encourage autonomy and cultural awareness of students and collaborative decision making with all; (10) establish trust and relationships; and (11) provide transparent feedback and assessment. It is believed that the results of the study will help teachers of MLs to comprehend the prominence of culturally responsive teaching. Additionally, implications include advising policymakers to acknowledge that covering the curriculum in a timely manner for MLs is not enough for sustained success.
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Title: Examining Perceptions of Motivation, Athlete Burnout, and Injury-Related Fear in Patients Following ACL Reconstruction
Creator: Murray, Megan
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Approximately 1 out of 3 patients fail to return to previous levels of sport participation after anterior cruciate ligament reconstruction (ACLR), with injury-related fear identified as a potential barrier for return to sport. However, we do not know how injury-related fear is associated with other meaningful psychological responses to injury, or how patient perceptions of these psychological responses relate to their rehabilitation experiences. The purpose of this cross-sectional,...
Show moreApproximately 1 out of 3 patients fail to return to previous levels of sport participation after anterior cruciate ligament reconstruction (ACLR), with injury-related fear identified as a potential barrier for return to sport. However, we do not know how injury-related fear is associated with other meaningful psychological responses to injury, or how patient perceptions of these psychological responses relate to their rehabilitation experiences. The purpose of this cross-sectional, explanatory sequential mixed-methods study was to explore how perceptions of self-determined motivation, athlete burnout, and injury-related fear affected psychological experiences during ACLR rehabilitation in patients between 4- and 6-months post-ACLR. 13 participants were recruited and completed questionnaires measuring self-determined motivation, athlete burnout, perceived stress, and injury-related fear. A sub-sample of 5 participants participated in a semi-structured interview to further underline patient experiences during ACLR rehabilitation. A strong, positive relationship was observed between perceived stress and injury-related fear (rho = 0.70, p = 0.008). Thematic analysis revealed five themes related to the rehabilitation experience: 1) struggling with the recovery process, 2) acknowledging negative emotional states, 3) drive to return to sport and normal life, 4) understanding and finding purpose in rehabilitation, and 5) successfully navigating the recovery process. These preliminary data suggest that negative emotional states, such as injury-related fear and athlete burnout, may be related to self-determined motivation and perceived stress after ACLR.
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Title: Environmental Microbial Surveillance : From Source Tracking in Watersheds to Pathogen Monitoring in Sewersheds
Creator: Flood, Matthew Thomas
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Understanding of the connections between water and health, through the use of water quality monitoring, surveys and surveillance, can help to address the impacts of anthropomorphic changes on the environment. This study sought to understand these connections through the water quality monitoring within watershed basins as well as pathogen surveillance within sewersheds. Specifically, this dissertation sought to 1) understand the sources of pollution and their connections with land use in the...
Show moreUnderstanding of the connections between water and health, through the use of water quality monitoring, surveys and surveillance, can help to address the impacts of anthropomorphic changes on the environment. This study sought to understand these connections through the water quality monitoring within watershed basins as well as pathogen surveillance within sewersheds. Specifically, this dissertation sought to 1) understand the sources of pollution and their connections with land use in the various subsections of watersheds; 2) to find a cost-effective way to surveil the spread of SARS-CoV-2 using wastewater surveillance; and 3) to understand the differences in wastewater surveillance between communities. Water quality monitoring using microbial source tracking (MST) was performed with a survey of five mixed-use watersheds in Michigan. Through the use of spatial clustering, it was found that temporal contamination was primarily driven by precipitation and its associated variables (e.g., streamflow, turbidity, overland flow), while spatial contamination is driven by land uses (e.g., septic tank density, tile drain proportions, and tillage). Additionally, porcine fecal contamination was more often correlated with nutrients in streams than either bovine or human contamination. The development of a cost-effective workflow for the detection and quantification of SARS-COV-2 in wastewater was undertaken. Wastewater from communities around Michigan were collected and analyzed along with viral surrogates for SARS-CoV-2 to investigate different workflow options. The Pseudomonas phage Phi6 was seeded in different wastewater matrices to test concentration and recovery by ultrafiltration-based method and polyethylene glycol (PEG) precipitation. The PEG method provided better virus recovery than the ultrafiltration-based methods as measured using RT-ddPCR. The comparison of two communities (A and B) wastewater results for SARS-CoV-2 analyzed against case data was undertaken. These results were significantly correlated with cases in both communites, but the level of correlation differed based on spatial (e.g., zipcode vs county level cases) and temporal (e.g., date of symptom(s) onset vs. the referral date for cases) resolution. Wastewater surveillance was more representative of higher spatial resolution (zipcode data) of cases in both communities. When examining the temporal resolution of the communities, community B’s wastewater results were more closely tied to the onset of symptoms and not the case referral date. The ability to monitor indicators of pollution in watersheds and surveil etiological agents of disease in sewersheds provide non-intrusive methods for evaluating the potential risks and current burdens to community health. The first part of the work could be considered “downstream” monitoring identifying sources and potential exposures with the goal of reducing waterborne disease. While “upstream” monitoring was used for identifying the disease trends in the community and was focused on public health measures to prevent transmission. This project contributed novel methods, results and analysis providing valuable knowledge ultimately addressing the role of monitoring strategies to protect public health.
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Title: Application of density functional theory in nuclear structure
Creator: Li, Tong
Date: 2022
Collection: Electronic Theses & Dissertations
Description: The nuclear density functional theory (DFT) is a microscopic self-consistent framework suitable for describing heavy nuclei and performing large-scale studies. In this dissertation I discuss my research works on the development and application of the Skyrme nuclear-DFT framework, covering a broad range of topics, including the nucleon localization in rotating systems, the origin of reflection-asymmetric deformations, the parameter calibration for beta decays, and the development of a new...
Show moreThe nuclear density functional theory (DFT) is a microscopic self-consistent framework suitable for describing heavy nuclei and performing large-scale studies. In this dissertation I discuss my research works on the development and application of the Skyrme nuclear-DFT framework, covering a broad range of topics, including the nucleon localization in rotating systems, the origin of reflection-asymmetric deformations, the parameter calibration for beta decays, and the development of a new coordinate-space DFT solver.The nucleon localization function (NLF), discussed in the first part, is a useful tool for the visualization of structure information. It has been utilized to characterize clustering and shell structure. How the NLF pattern evolves in rotating systems, how it visualizes internal nuclear structure, and how it is connected with single-particle (s.p.) orbits are discussed in this dissertation. The second part deals with nuclei having reflection-asymmetric shapes, which are important candidates for the search of permanent electric dipole moments. In this dissertation, the origin of pear-like deformation is investigated through both the multipole expansion of the energy density functional and the spectrum of canonical s.p. states. Theoretical predictions of beta-decay rates are discussed next; they are important for r-process simulations that involves nuclei whose experimental beta-decay data are unknown. To provide reliable predictions with quantified uncertainties, the χ^2 optimization is performed to constrain parameters that significantly affect beta-decay transitions in proton-neutron finite-amplitude-method calculations. Besides a well calibrated functional, a reliable and efficient DFT solver is also crucial. The Hartree-Fock-Bogoliubov (HFB) method in the coordinate space is preferred for deformed and weakly bound nuclei, as solvers based on basis expansions often have difficulty correctly describing continuum effects. A new HFB solver based on the canonical-basis HFB formalism in the three-dimensional coordinate space is developed in this dissertation. It is a well parallelized solver and has been carefully benchmarked against other established HFB solvers.
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Title: STUDENTS’ CONCEPTIONS OF THEIR CAMPUS LGBTQ+ CENTER
Creator: Noble, Chelsea E.
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Lesbian, gay, bisexual, transgender, queer, and similar identities (LGBTQ+) resource centers on college campuses provide services, resources, programming, and advocacy focused on gender and sexuality, especially minoritized genders and sexualities. As center staff enact this work at the individual and organizational levels, LGBTQ+ centers seek to promote students’ thriving, especially among students with minoritized genders and sexualities. Although students are the animating reason for LGBTQ...
Show moreLesbian, gay, bisexual, transgender, queer, and similar identities (LGBTQ+) resource centers on college campuses provide services, resources, programming, and advocacy focused on gender and sexuality, especially minoritized genders and sexualities. As center staff enact this work at the individual and organizational levels, LGBTQ+ centers seek to promote students’ thriving, especially among students with minoritized genders and sexualities. Although students are the animating reason for LGBTQ+ centers’ existence, relatively little is known about how students experience and conceptualize campus LGBTQ+ resource centers. The purpose of this study was to understand LGBTQ+ resource centers from students’ perspectives. Guided by a critical adaptation of an ecological model of development (Bronfenbrenner, 1993; Renn & Arnold, 2003), I undertook a qualitative study drawing on interviews with 15 students who felt in some way connected to their campus LGBTQ+ center. I also included data from observations and publicly available center documents. The participants were all current students at a Midwestern university where the LGBTQ+ center had at least one full-time staff member and a clear commitment to social justice. The campus LGBTQ+ center often served as an important force in students’ ecosystems. Students’ ecosystems reflected common elements of university education (e.g., classes, student organizations, and friends), LGBTQ+ campus spaces, families and communities of origin, as well as broader forces including U.S. politics, the COVID-19 pandemic, and a number of oppressive systems. In the midst of highly variable, often unsupportive, and sometimes hostile contexts, students found support and guidance through their LGBTQ+ center. Students experienced their center in five major ways: physical space, source of relationships, organizational navigation and tools, virtual presence, and symbol of institutional commitment. Students emphasized and interacted with each of these aspects in accordance with their needs as they navigated their academic pursuits and daily lives in the face of racism, cissexism, heterosexism, and a host of other oppressive forces. Ultimately, students’ experiences with their campus LGBTQ+ center were frequently a means of survival and a boost towards students thriving on campus and in their lives.
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Title: ALFALFA, CUCUMBER, DRY BEAN, AND SUGARBEET RESPONSE TO BICYCLOPRYONE AND MESOTRIONE
Creator: Wilkinson, Daniel Douglas
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Bicyclopyrone and mesotrione are a HPPD-inhibiting herbicide (Group 27) registered for use in corn. Mesotrione is sold alone or in premixture with other herbicides; bicyclopyrone is sold only in premixtures. There is limited data available on the response of other crops planted into fields where these herbicides were applied. Greenhouse and field experiments were conducted to evaluate alfalfa, cucumber, black and kidney bean, and sugarbeet response to bicyclopyrone and mesotrione. In the...
Show moreBicyclopyrone and mesotrione are a HPPD-inhibiting herbicide (Group 27) registered for use in corn. Mesotrione is sold alone or in premixture with other herbicides; bicyclopyrone is sold only in premixtures. There is limited data available on the response of other crops planted into fields where these herbicides were applied. Greenhouse and field experiments were conducted to evaluate alfalfa, cucumber, black and kidney bean, and sugarbeet response to bicyclopyrone and mesotrione. In the greenhouse, cucumber, black bean, kidney bean, and sugarbeet were more sensitive to mesotrione compared with bicyclopyrone. Sugarbeet was the most sensitive to both bicyclopyrone and mesotrione followed by alfalfa. Cucumbers were the most tolerant to bicyclopyrone and mesotrione followed by kidney bean and black bean. In field research, bicyclopyrone at 50 and 100 g ha-1 (1 and 2X rate), and mesotrione at 210 g ha-1 were applied in early June to V4 corn at two locations in 2015 and 2016. The following spring, alfalfa and sugarbeet were planted in mid-April and cucumber and dry edible bean in early-June and crop response was measured. In 2016, injury in all crops was less than 20%, regardless of herbicide treatment at either location. In 2017 at East Lansing, sugarbeet was severely injured and did not survive where mesotrione was applied the previous year. Sugarbeet and kidney bean injury was 15 and 5%, respectively from the 2X rate of bicyclopyrone. Neither mesotrione or bicyclopyrone affected crop growth or yield at Richville in 2017. Soil pH was 6.0 and soil organic matter was 4.2 to 4.5% at East Lansing and soil pH was 7.8 and soil organic matter 2.6% at Richville. While there were differences in soils at the two locations, rainfall within the first 30 days following application contributed to differences in herbicide carryover. At East Lansing, rainfall was 20.5 and 2.8 cm within the first 30 days following application in 2015 and 2016, respectively, contributing to more herbicide carryover in the 2017 growing season than in the 2016 growing season. Rainfall at Richville had a 60% reduction in precipitation within the first 30 days however, no herbicide carryover was experienced. From this research it appears that alfalfa, dry bean or cucumber can be planted the year following mesotrione or bicyclopyrone application. However, sugarbeet should not be planted the year following applications of mesotrione or bicyclopyrone.
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Title: EXPERIMENTAL INVESTIGATIONS OF Al-BASED INITIATIOR FOR (CO)POLYMERIZATION OF EPOXIDES AND EPISULFIDE AND APPLICATION TOWARD MEMBRANE SYNTHESIS
Creator: Safaie Ashtiani, Niloofar
Date: 2022
Collection: Electronic Theses & Dissertations
Description: We developed a novel aluminum-based initiator for epoxide polymerization which facilitated polymerization of various epoxides (epichlorohydrin, propylene oxide, etc.) and episulfide up to molecular weights of 100 kg/mol while maintaining relatively narrow polydispersity (Ð < 1.3). The initiator was simply synthesized through the reaction of a thiol ligand and trialkyl aluminum, with the thiol ligand choice enabling polymer end group control. Copolymerization of epichlorohydrin and propylene...
Show moreWe developed a novel aluminum-based initiator for epoxide polymerization which facilitated polymerization of various epoxides (epichlorohydrin, propylene oxide, etc.) and episulfide up to molecular weights of 100 kg/mol while maintaining relatively narrow polydispersity (Ð < 1.3). The initiator was simply synthesized through the reaction of a thiol ligand and trialkyl aluminum, with the thiol ligand choice enabling polymer end group control. Copolymerization of epichlorohydrin and propylene oxide and copolymerization of different epoxides with episulfide demonstrated the ability of this method to control polymer architecture. We further investigated the effect of catalyst concentration and initiator structure on the kinetics of epoxide polymerizations through 1H NMR spectroscopy. Finally, we combined our method of polymerization with another facile method, reversible addition fragmentation with chain transfer (RAFT) polymerization, to synthesize block-co-polymers made from vinyl and epoxide monomers. To do this, we made a macroinitiator from polystyrene (PS) and poly(methyl methacrylate) (PMMA), synthesized by RAFT polymerization, and further polymerized epoxide from it. Therefore, this new synthetic tool allows for the facile and controlled polymerization of epoxides into well-defined, functional, polyether materials. Furthermore, the introduced innovative and reliable methodology for the synthesis of SAl initiators enabled us to tune the polymer architecture to readily access more complex structure of polyepisulifides. We synthesized di-functional (d-H) and tetra-functional (t-H) SAl initiators to produce ABA and star-(co)polymers consisting of propylene sulfide and PO or ECH. Finally, polyethylene glycol (PEG) was used as a macroinitiator to create PEG-b-PPS block copolymers and characterized by 1H, 13C NMR spectroscopy, DOSY, DSC, and SEC. Motivated by the result, we prepared the star shape cross linked membrane from t-H initiator. The composition was controlled through the monomer feed ratio of propylene oxide (PO) and epichlorohydrin (ECH) for synthesis of PPO-PECH membrane in the presence of poly(ethylene oxide)-diglycidyl ether as a cross linker and the most optimized PPO-PECH with the ratio of 90:10 resulted optically clear and flexible film. We further modified the membrane with a range of amines like trimethylamine (TEA), dimethylamine (DMA), triethylamine (TEA), and diethylamine (DEA) by membrane dipping method. The chemical, physical, and mechanical properties of resultant secondary amine grafted and quartenized membranes were characterized as a candidate for CO2 transport. Moreover, we designed the facilitated transport membranes of crosslinked ether-based PPO-PECH membranes with the range of hindered and unhindered primary amines using previously reported mono(μ-alkoxo)- bis(alkylaluminum) (MOB). The physical and chemical properties of the membranes investigated by FT-IR spectroscopy, DSC, TGA, and rheology. This method demonstrated a simple and robust strategy to prepare copolymers cross linked membranes containing amines for CO2 transport. This enables us to compare the effect of different amines in the structure of facilitated transport membranes. In this thesis research we seek to develop a SAl initiator as a platform that is both simple to use and can synthesize new polymeric materials. This methodology is simple and tunable to produce robust crosslinked membranes for molecu
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Title: UNDERSTANDING THE IMPACT OF SEXUAL ASSAULT RELATED SOCIAL MEDIA CONTENT ON SURVIVORS : AN EXPLORATORY SEQUENTIAL MIXED METHODS STUDY
Creator: PettyJohn, Morgan E.
Date: 2022
Collection: Electronic Theses & Dissertations
Description: In recent years, hashtag activism movements (i.e., using a common message or phrase to unite user voices to address injustice; Yang & Kaun, 2016) have unfolded across social media (SM) platforms to bring attention to the prevalence and impacts of sexual assault. Specifically, the online #MeToo Movement went viral around the world in 2017, resulting in increased news coverage and public discourse surrounding this topic (Anderson & Toor, 2018). Indeed, nearly half (44%) of women in the United...
Show moreIn recent years, hashtag activism movements (i.e., using a common message or phrase to unite user voices to address injustice; Yang & Kaun, 2016) have unfolded across social media (SM) platforms to bring attention to the prevalence and impacts of sexual assault. Specifically, the online #MeToo Movement went viral around the world in 2017, resulting in increased news coverage and public discourse surrounding this topic (Anderson & Toor, 2018). Indeed, nearly half (44%) of women in the United States experience unwanted sexual contact in their lifetime (Smith et al., 2018) and these violations are associated with increased risk for negative mental health outcomes, including depression, anxiety, and posttraumatic stress disorder (PTSD; Mason & Lodrick, 2013). After experiencing interpersonal violence, reminders of the trauma (e.g., words, images) can trigger psychophysiological reactions for survivors, such as emotional dysregulation, physical symptoms (e.g., heart racing), and increases in adverse mental health symptomatology (Mchugo et al., 2001; Moser et al., 2015). Given the popularity of SM among women in the U.S. (78% report usage; Pew Research Center, 2019), survivors of sexual assault are presumably being exposed to trauma related content connected to popular hashtag activism movements while spending time online. However, little is known about how exposure to sexual assault narratives and related discourse in this context could impact the mental health and relationships of survivors.The present study aims to address this gap in the literature by using an exploratory sequential mixed methods design to better understand survivors’ online experiences during this unique cultural moment. The qualitative strand of the study utilized thematic analysis of semi-structured interviews (n = 12) to explore the lived experiences of young women survivors (18-34 years old) using SM since initiation of the #MeToo Movement. Survivors described adverse changes in their mental health during periods of intense media coverage relating to sexual assault stories (e.g., Dr. Christine Blasey Ford’s Senate testimony). Some survivors also reported negative changes in their personal relationships with people in their life based on how they discussed sexual assault on these platforms. Findings from the qualitative strand were used to inform development of an online, cross-sectional quantitative survey, facilitated through CloudResearch’s MTurk toolkit. Multiple regression analyses found general SM use, exposure to sexual assault content, and exposure to unsupportive attitudes (i.e., victim blaming or perpetrator supporting) to be significantly predictive of depression, anxiety, and PTSD symptomatology among young women, both survivors (n = 312) and non-victims (n = 171). Survivors reported noticing people from their support systems (e.g., family, friends, co-workers) posting unsupportive attitudes about other victims’ stories at significantly higher rates than non-victims. Findings from the present study implore clinicians to assess SM use and level of exposure to sexual assault related content among clients, particularly those who have experienced sexual assault. Further, clinicians should stay informed about viral news stories and hashtag activism movements addressing sexual assault and provide space for clients to process this content during times of high saturation on SM platforms.
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Title: When is "Tough Love" Too Much? An Exploratory Study of Tough Love Coaching in Sport
Creator: Saxton, Sarah
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Tough love is often discussed in sport, but there is not a clear understanding of what tough love is, which tough love behaviors are commonly used by coaches and how effective they are, or which factors may influence the effectiveness of tough love strategies. Additionally, tough love may cross over into abuse or maltreatment if approached incorrectly. The purpose of this study was to propose a definition of tough love coaching, identify effective tough love strategies, determine whether...
Show moreTough love is often discussed in sport, but there is not a clear understanding of what tough love is, which tough love behaviors are commonly used by coaches and how effective they are, or which factors may influence the effectiveness of tough love strategies. Additionally, tough love may cross over into abuse or maltreatment if approached incorrectly. The purpose of this study was to propose a definition of tough love coaching, identify effective tough love strategies, determine whether tough love coaching can be inappropriate or harmful to the athlete, and identify individual factors that influence the way in which tough love is received by athletes. This study adopted a basic interpretive approach to qualitative research by using semi-structured interviews to investigate athletes’ experiences with and feelings toward tough love in sport. Specifically, in-depth interviews were conducted with 12 current and former athletes (three males, nine females) ranging in age from 18 to 27 who had or were participating in a variety of sports. Thematic analysis was conducted on the transcribed interviews to identify relevant themes, subthemes and categories in the data. Four major results were found. First, a definition of tough love coaching was proposed. Second, examples of effective, ineffective, and harmful tough love strategies were provided. Third, factors perceved to influence tough love’s effectiveness were identified, including the coach-athlete relationship, coach demographics, athlete characteristics, sport demographics, encouragement and support, clear feedback, frequency of use, motivational climate, and privacy. Fourth, the “line” between tough love and harmful or abusive coaching was identified. Results are discussed relative to the coaching feedback and approaches as well as maltreatment in sport reseach literature.
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Title: DIVERSIFYING AGRICULTURAL LANDSCAPES FOR BIODIVERSITY AND ECOSYSTEM SERVICES
Creator: Kemmerling, Lindsey Renee
Date: 2022
Collection: Electronic Theses & Dissertations
Description: This dissertation focuses on strategies to restore biodiversity and ecosystem services in agricultural landscapes through diversifying the plant community at the landscape level. Biodiversity and ecosystem services are declining globally, and a leading cause of this decline is large-scale row crop agriculture which results in habitat loss and pollution. Simultaneously, the human population is growing, as are human demands for resources produced by agriculture. Diversifying agricultural...
Show moreThis dissertation focuses on strategies to restore biodiversity and ecosystem services in agricultural landscapes through diversifying the plant community at the landscape level. Biodiversity and ecosystem services are declining globally, and a leading cause of this decline is large-scale row crop agriculture which results in habitat loss and pollution. Simultaneously, the human population is growing, as are human demands for resources produced by agriculture. Diversifying agricultural landscapes is one method to both mitigate the loss biodiversity while providing essential human resources. I conducted three studies that test if diversifying cropping systems can increase biodiversity and ecosystem services and maintain or even increase agricultural yield. In Chapter 1, I tested the ability of multiple native, perennial bioenergy crops (alternatives to annual bioenergy crops) to provide both crop yield and conserve pollinators. I measured pollinator abundance and species richness, flower abundance and species richness, and crop yield across four native perennial biofuel crop varieties: successional land (unmanaged), restored prairie, a mix of native grasses, and seeded switchgrass. Successional land had the most diverse community of pollinators but the lowest crop yield, native grasses had the highest yield but the least diverse pollinator community, and switchgrass and restored prairie were intermediate. If both pollinator conservation and crop yield are valued similarly, restored prairie was the optimal biofuel crop. Chapter 2 tested the effects of crop management practices in row crop agriculture, including the establishment of a conservation practice called “prairie strips” on biodiversity and ecosystem services. Prairie strips are strips of farmland retired from production and actively restored with native prairie plant species. I synthesized the tradeoffs and synergies of a suite of biodiversity and ecosystem service measures across a land use intensity gradient, as well as their spillover from prairie strips into cropland. The lowest land use intensity consistently had the highest levels of biodiversity and ecosystem services other than crop yield. Treatments with prairie strips had higher pollination services and a higher abundance of butterflies and spiders than other row crop treatments. Crop yield in a treatment with low land use intensity and prairie strips remained as highest land use intensity treatment, even when including the area taken out of production for prairie strips. Biodiversity and ecosystem services decreased with increasing distance from prairie strips and this effect was more pronounced in the second year of the prairie strips than the first for several measures. These results show that, even in early establishment, prairie strips can contribute to the conservation of biodiversity and ecosystem services without a disproportionate loss of crop yield. Chapter 3 further investigated one of the measures addressed in Chapter 2: butterfly biodiversity. I measured butterfly and plant species richness and abundance across three years in the same land use intensity gradient. Butterfly abundance and richness increased as land use intensity decreased. Prairie strips harbored unique butterfly communities and had a higher abundance of butterflies than other row crop treatments, including conservation land. Across the 1 ha plot of which 5% was prairie strip, butterfly abundance was higher in row crops with prairie strips than in row crops without prairie strips, likely as a result of prairie strips and other crop management practices in treatments with prairie strips, such as reduced pesticides. Altogether, this work presents evidence that restoring habitat within farms can support biodiversity and ecosystem services without disproportionately impacting crop yields. Furthermore, when strategically placed, these conservation strategies can prevent unnecessary greenhouse gas emissions, and potentially increase crop yield.
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Title: DO INFORMATION ACQUISITION COSTS MATTER? THE EFFECT OF SEC EDGAR ON STOCK ANOMALIES
Creator: Kim, Yong-Hyuck
Date: 2022
Collection: Electronic Theses & Dissertations
Description: I estimate the costs of information acquisition and the extent to which they explain stock anomaly returns. The SEC’s staggered implementation of EDGAR from 1993 to 1996 greatly lowered the costs of acquiring accounting information. I study how this quasi-exogenous and staggered shock affects the profitability of 126 accounting and 108 non-accounting anomalies. The EDGAR introduction lowers the average alphas for the accounting anomalies by 4.0% per year, explaining more than half of the pre...
Show moreI estimate the costs of information acquisition and the extent to which they explain stock anomaly returns. The SEC’s staggered implementation of EDGAR from 1993 to 1996 greatly lowered the costs of acquiring accounting information. I study how this quasi-exogenous and staggered shock affects the profitability of 126 accounting and 108 non-accounting anomalies. The EDGAR introduction lowers the average alphas for the accounting anomalies by 4.0% per year, explaining more than half of the pre-EDGAR alphas. The attenuation is stronger for the accounting anomaly portfolios that require more up-to-date accounting information and those consisting of EDGAR filer stocks with less information available in the pre-EDGAR period. By contrast, alphas for the non-accounting anomalies remain unaffected. These results imply that the information acquisition costs, which are usually neglected, can be as important as the transaction or short sale costs.
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Title: COVID-19 information sharing on social media : Channels and Motives from the Kazakhstani people's perspective
Creator: Moldagaliyeva, Moldir
Date: 2022
Collection: Electronic Theses & Dissertations
Description: COVID-19 pandemic news has become popular and topical content for the last couple of years. And the wide usage of social media across the globe makes it easy to share information, including misinformation, about COVID-19. Although sharing news on social media has been actively studied in most western countries, little attempt has been made to look into the issue from the perspectives of developing countries where the amount of social media use has been increasing enormously over the last...
Show moreCOVID-19 pandemic news has become popular and topical content for the last couple of years. And the wide usage of social media across the globe makes it easy to share information, including misinformation, about COVID-19. Although sharing news on social media has been actively studied in most western countries, little attempt has been made to look into the issue from the perspectives of developing countries where the amount of social media use has been increasing enormously over the last years. Besides, almost nothing is known about the social media users’ choice of a particular platform when they decide to share information and misinformation, especially within the context of the COVID-19 pandemic. Therefore, this master’s thesis explored how motivation factors Kazakhstani people follow when sharing COVID-19 news shape their decision to share COVID-19 news on specific social media platforms and their COVID-19 misinformation sharing patterns.The study used a quantitative research method approach, surveying 288 people from Kazakhstan over 18 years old.
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Title: NUMERICAL SIMULATIONS OF PERMEABLE-WALL TURBULENCE WITH APPLICATIONS IN HYPORHEIC EXCHANGE
Creator: SHEN, GUANGCHEN
Date: 2022
Collection: Electronic Theses & Dissertations
Description: In aquatic environments such as rivers, the exchange of solutes across the interface between the sediment and the overlying water plays a signifcant role in controlling biogeochemical processes, which are important for an array of topics from nutrient transport and cycling to release of greenhouse gases such as nitrous oxide. Most previous studies on characterizing this exchange are focused on flows with sediment bedforms much larger than individual sediment grains. The physics at the pore or...
Show moreIn aquatic environments such as rivers, the exchange of solutes across the interface between the sediment and the overlying water plays a signifcant role in controlling biogeochemical processes, which are important for an array of topics from nutrient transport and cycling to release of greenhouse gases such as nitrous oxide. Most previous studies on characterizing this exchange are focused on flows with sediment bedforms much larger than individual sediment grains. The physics at the pore or grain scale were typically not resolved. The effects of grain roughness on the sedimentbed surface on the transport across the sediment-water interface (SWI), isolated from those of bed permeability and bedforms, are not well understood. In this work, direct numerical simulations (DNS) of the connected system of turbulent open-channel flow and pore-resolved sediment flow are carried out, with different arrangements of grains at the sediment surface.First, the statistics and structure of the mean flow and turbulence are characterized in flows with a friction Reynolds number of 395 and a permeability Reynolds number of 2.6 over sediments with either regular or random grain packing on a macroscopically flat bed. It is shown that, even in the absence of any bedform, the subtle details of grain roughness alone can signifcantly affect the dynamics of turbulence and the time-mean flow. Such effects translate to large differences in penetration depths, apparent permeabilities, vertical mass fluxes and subsurface flow paths. The less organized distribution of mean recirculation regions near the interface with a random packing leads to a more isotropic form-induced stress tensor, which plays a signifcant role in increasing mixing and wall-normal exchange of mass and momentum.Next, the mass exchange is characterized in detail for macroscopically flat river beds, focusing on the transit time—the time spent by a fluid particle in the sediment—which determines the role of hyporheic zones in transforming the chemical signature of stream water. Results show that bedroughness leads to interfacial pressure variations, which induces deep subsurface flow paths that yield a transit time distribution with a heavy tail. Furthermore, the addition of molecular diffusionis accounted for and is shown to increase transit times regardless of roughness texture. The results demonstrate that particle roughness on a macroscopically flat sediment bed can induce signifcant hyporheic exchange that is fundamentally similar to that induced by bedforms.Lastly, to identify possible interaction between the effect of grain roughness and that of a bedform, DNSs of open channels with a friction Reynolds number of 1580 on a porous dune with two different roughnesses are conducted. Results show that the roughness modifes the wall friction, shear penetration depth and pressure distribution along the interface. Unlike the case on a macroscopically flat bed where the random roughness induces more intense roughness-scale pressure variation than the regular roughness, over a bedform the random roughness reduces the macroscopic pressure distribution at the interface instead due to its higher hydrodynamic drag. The weaker pressure variation in turn weakens the pumping and shortens transit times. The results highlight the nonlinear interaction between the effects of bed morphological features of different scales. Pore-resolved simulations such as the ones herein can be used in the future in direct characterization of pore-scale dynamics to provide insights for pore-unresolved modeling of biogeochemical processes.
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Title: Contextual Support, Resilience, Allostatic Load, and Mental Health in Transgender and Gender Diverse Individuals
Creator: Kimball, Devon Mary
Date: 2022
Collection: Electronic Theses & Dissertations
Description: A growing body of literature suggests that how much support TGD individuals experience in the places they live, including their present context and context of origin, can influence their wellbeing. Other research about physical health has found exposure to stressors has physiological effects on sexual and gender minority people, which can be measured through allostatic load (a selection of multiple physiological indicators that reflects “wear and tear” on the body; AL). Research on mental...
Show moreA growing body of literature suggests that how much support TGD individuals experience in the places they live, including their present context and context of origin, can influence their wellbeing. Other research about physical health has found exposure to stressors has physiological effects on sexual and gender minority people, which can be measured through allostatic load (a selection of multiple physiological indicators that reflects “wear and tear” on the body; AL). Research on mental health has also indicated that TGD individuals are at higher risk of depression and anxiety. TGD populations also have unique resilience factors that are important to consider, such as pride and community connectedness, which may influence health outcomes. This study used latent class analysis to examine how individuals clustered based on current and past levels of contextual support, and then examined the relationship between these classes and AL, depression, and anxiety, including whether pride and community connectedness moderated these relationships. Contextual support across the lifetime was also examined as a continuous variable. Participants either had lived consistently in contexts with high levels of support (High Support class), had moved from contexts with low levels of support to high levels of support (Low to High Support class), or had consistently lived in contexts with low levels of support (Low Support class). Individuals in the Low Support class had lower levels of AL compared to their peers in the High Support class. There were no associations between class and depression and anxiety, and there were no moderating effects of community connectedness or pride. This study suggests that contextual support may not influence depression and anxiety among TGD people, but that lower levels of support may actually correlate with decreased AL.
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Title: WHAT HAPPENS DURING AND AFTER MULTITASKING? CONCURRENT AND CARRY-OVER EFFECTS OF MEDIA MULTITASKING AND SELF-REGULATION ON TASK PERFORMANCE
Creator: Baek, Jong-Hwan
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Much research has suggested that multitasking impairs cognitive outcomes and task performance. Given its negative role in information processing, the vast majority of work has focused on concurrent effects during multitasking (e.g., recall, recognition). However, prior research in the multitasking literature has rarely examined short-term or lingering effects on subsequent tasks. One of the theories concerning this after-effect is ego depletion, a state of reduced self-regulatory resources.To...
Show moreMuch research has suggested that multitasking impairs cognitive outcomes and task performance. Given its negative role in information processing, the vast majority of work has focused on concurrent effects during multitasking (e.g., recall, recognition). However, prior research in the multitasking literature has rarely examined short-term or lingering effects on subsequent tasks. One of the theories concerning this after-effect is ego depletion, a state of reduced self-regulatory resources.To this end, the present study examined concurrent and carry-over effects of multitasking and self-regulation on task performance. Specifically, the current study examined whether the effects of media multitasking with different attentional demands vary by self-regulation (i.e., single-task, multitask with divided attention, multitask with selective attention, multitask with flexible attention) and how such effects occur during and after multitasking. Consistent with predictions, media multitasking decreased performance on subsequent self-control and cognitive tasks. Also, participants in the multitasking condition with flexible attention watched a subsequent movie longer, and they perceived it as more enjoyable than those in the single-task condition. Additionally, findings showed how exerting self-regulation could lead to better performance on both primary and secondary tasks. Findings and implications for research on media multitasking are further discussed.
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Title: Tunable Fluorescent Organic Salts for Imaging and Therapy
Creator: Broadwater, Deanna May
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Cancer remains a leading cause of death worldwide and many treatments still rely on non-targeted chemotherapy, which has inadequate efficacy and is plagued by toxic side effects. A promising solution is photodynamic therapy (PDT), a noninvasive clinical cancer treatment that combines a light activated photosensitizer (PS) with excitatory light to generate toxic reactive oxygen species (ROS). These photoactive agents can also produce detectable wavelengths of light upon photoactivation, which...
Show moreCancer remains a leading cause of death worldwide and many treatments still rely on non-targeted chemotherapy, which has inadequate efficacy and is plagued by toxic side effects. A promising solution is photodynamic therapy (PDT), a noninvasive clinical cancer treatment that combines a light activated photosensitizer (PS) with excitatory light to generate toxic reactive oxygen species (ROS). These photoactive agents can also produce detectable wavelengths of light upon photoactivation, which has been used clinically to image tumors in cancer diagnostics and image-guided surgery. Having uses as both diagnostic and therapeutic agents, these molecules are known as theranostics. However, current light-activated theranostics are limited by low brightness, poor tissue penetration, and nonspecific cytotoxicity independent of light excitation. Due to these obstacles, PDT is currently limited to precancerous lesions, superficial neoplastic tissue, or palliative care. Therefore, improved theranostic agents are needed. Prevailing efforts to improve existing photoactive agents focus on chemical modifications that cannot independently control electronic properties (which dictate toxicity) from optical properties. To overcome these limitations, work in this dissertation develops a novel counterion pairing platform to modulate the toxicity of organic salts composed of a photoactive cationic heptamethine cyanine (Cy+) and a non-photoactive anion. These counterion-tuned fluorescent organic salts can be designed to be either nontoxic for imaging, or phototoxic for PDT. Organic salts self-organize into nanoparticles with shifted frontier molecular orbital levels dependent on the counterion while the bandgap remains the same. This allows for tuning of electronic properties without affecting optical properties. Improvements in these areas could expand light-activated theranostics into a wider range of cancers and improve patient outcomes. This dissertation will begin with a review of current photoactive agents used in cancer therapy and ongoing challenges to the adoption of PDT as a frontline therapy. Modern PDT regimens and potential combinatorial therapies will be appraised, and recent advances in rational PS design will be highlighted. Initial in vitro studies investigated the optoelectronic tuning capabilities of counterion pairing in human lung carcinoma (A549) and melanoma (WM1158) cell lines. Viability assays establish that pairings with weakly coordinating bulky anions could generate organic salts that are non-cytotoxic and selectively phototoxic, while pairing with standard hard anions yield cytotoxic organic salts. These studies demonstrate that anion pairing can be exploited to shift energy levels and influence ROS generation to either enhance photokilling of cancer cells or improve cell imaging. Organic salts were further investigated in a metastatic breast cancer mouse model to characterize biodistribution, antitumor efficacy within a complex tumor microenvironment, and off-site toxicity. In vivo experiments confirm that counterion tuning can generate a selectively phototoxic antitumor PS which abolishes tumor growth and reduces metastasis without systemic toxicity in a breast cancer mouse model. Overall, this work demonstrates the utility of using counterion tuning to control phototoxicity, and further demonstrates the untapped potential of photoactive theranostic agents for clinical cancer therapy.
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Title: ENHANCING CORPORATE CRIME ENFORCEMENT WITH MACHINE LEARNING—A MULTIDISCIPLINARY RISK FACTOR APPROACH
Creator: Chan, Fiona
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Despite its severe and lasting social and financial ramifications, corporate financial crime remains one of the most understudied crime types, as it is often hindered by two challenges. First, its multidisciplinary nature requires both financial and criminological expertise among others to conduct proper investigations. Second, corporate crime data is fraught with constraints such as high dimensionality, complex interactions, and nonlinear functional forms that are ill-suited for classical...
Show moreDespite its severe and lasting social and financial ramifications, corporate financial crime remains one of the most understudied crime types, as it is often hindered by two challenges. First, its multidisciplinary nature requires both financial and criminological expertise among others to conduct proper investigations. Second, corporate crime data is fraught with constraints such as high dimensionality, complex interactions, and nonlinear functional forms that are ill-suited for classical statistical modeling. The lack of research coupled with the limited resources in corporate crime enforcement represent a great impediment to the advancement of fraud interventions. This dissertation seeks to overcome these specific challenges by unifying cross-disciplinary financial fraud research under a risk factor framework, and by leveraging recent advancements in artificial intelligence. The goal is to examine whether two machine learning algorithms—random forest and neural network—can be used to enhance corporate fraud risk detection/prediction beyond more commonly employed analytical techniques. Findings from the analysis showed that the random forest algorithm outperformed logistic regression and a naïve classifier in a 1:1 matched sample. The neural network performed better than a naïve classifier but slightly worse than logistic regression. Feature selection improved the algorithms’ predictive accuracy and ability to distinguish between classes even further. Despite promising results from the 1:1 matched sample, both machine learning algorithms struggled with a heavily imbalanced 1: many dataset, which represents a more realistic setting. With the implementation of an oversampling strategy and feature selection, the algorithms improved substantially in identifying the rare fraud cases, and showed promise of improvement with further research on imbalanced classification. Feature importance from the random forest classifier identified risk factors that are consistent with findings from prior studies. Measures of financial distress ranked lower in importance than measures of financial health, suggesting future research can build on prior findings on corporate strain to examine specific mechanisms. The analysis also identified auditor independence as a key concept of guardianship and opportunity structure that warrants further study. Findings from this research also have important methodological implications for corporate crime studies—namely, the need to improve measurements of organizational-level fraud risk factors.
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Title: Topological Approaches for Quantifying the Shape of Time Series Data
Creator: Tymochko, Sarah
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Topological data analysis (TDA) is field that started only two decades ago and has already shown promise both in theory and in applications. The goal of TDA is to quantify the shape of data in a manner that is concise and robust using concepts from algebraic topology. Persistent homology, arguably the most popular tool from TDA, studies the shape of a filtered space by watching how its homology changes. The output of persistent homology is a persistence diagram, which encodes information...
Show moreTopological data analysis (TDA) is field that started only two decades ago and has already shown promise both in theory and in applications. The goal of TDA is to quantify the shape of data in a manner that is concise and robust using concepts from algebraic topology. Persistent homology, arguably the most popular tool from TDA, studies the shape of a filtered space by watching how its homology changes. The output of persistent homology is a persistence diagram, which encodes information about the changing homology.Persistent homology has shown success in various application areas; one ever growing area of study in this field is time series analysis. Nonlinear time series analysis is a research field in and of itself that aims to capture structure in time series data, however, it lacks theoretically justified tools to analyze the resulting structure. Persistent homology comes with a solid theoretical framework, is robust to noise, and quantifies the same type of structure as appears in time series data. Thus combining tools from time series analysis and TDA provides a new approach to analyze and quantify behavior in time series data.One field where time series are prevalent is dynamical systems, since a time series arises from a projection of a solution to a system. Specifically, given a time series, Takens' theorem can be leveraged to embed the time series as a point cloud in a higher dimensional space, where this point cloud is a sampling of the full state space. Then for each time series, persistent homology can be computed on the embedding. The result is a persistence diagram for each time series. The question then becomes how do we analyze this collection of persistence diagrams to learn something about the original time series data? Many people have developed methods to answer this question, through methods such as machine learning or statistics. This dissertation provides several new methods leveraging tools from both TDA and nonlinear time series analysis to study time varying data.
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