MSU Libraries Digital Repository (Michigan State University)
Not a member yet
106711 research outputs found
Sort by
Resonance Compensation Studies at the FNAL Recycler Ring
No full textThesis (Ph.D.)--Michigan State University. Physics - Doctor of Philosophy, 2024Circular accelerators, such as the ones in the Fermilab Accelerator Complex, are indispensable tools driving scientific discovery by propelling particles to high energies and high intensities. In the context of the Proton Improvement Plan II (PIP-II) at Fermilab, the Recycler Ring (RR) is confronted with the challenge of high-intensity operation. The space charge tune shifts at these intensities necessitate the mitigation of third-order resonances. By measuring the Resonance Driving Terms (RDTs) for each resonance line, their strengths and damaging effects can be quantified. The study is focused on the utilization of dedicated normal and skew sextupoles for the compensation of these resonance lines. By employing the response matrix method to measure the Resonance Driving Terms (RDTs) relative to the currents in these sextupoles, a methodical approach to simultaneously compensate individual and multiple third-order resonances has been developed and assessed. The assessment and verification incorporate mapping out beam losses through dynamic and static tune scans, along with the utilization of the Ion Profile Monitor (IPM) system for beam size measurements. Furthermore, optimization algorithms have been explored and incorporated into the resonance compensation scheme. Parallel, to the work done at Fermilab, the study extends its scope by performing related experiments at the CERN Proton Synchrotron Booster (PSB). For these experiments, multiple resonance lines in the tune diagram were compensated by optimizing the currents in the compensation elements with the aid of advanced optimization algorithms. High-intensity operation of the Recycler Ring involves understanding the interplay between the space charge tune spread, resonance lines, and specialized subsystems such as transverse dampers. The following study also delves into experiments that try to discern each of these phenomena, while highlighting challenges still ahead. Overall, these studies indicate the feasibility of compensating for multiple third-order resonances, contributing to the objectives of PIP-II for the reliable delivery of a 1.2 MW proton beam to experimental facilities.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
DEVELOPMENT AND APPLICATIONS OF SEMI-STOCHASTIC COUPLED-CLUSTER METHODS FOR OPEN-SHELL SYSTEMS AND ELECTRONIC EXCITATIONS IN MOLECULES
No full textThesis (Ph.D.)--Michigan State University. Chemistry - Doctor of Philosophy, 2024It is well established that the exponential wave function ansatz of coupled-cluster (CC) theory and its equation-of-motion (EOM) extension to excited states are among the most appealing ways to describe the electronic structure of molecules. One of the key challenges in the development of the CC and EOMCC methodologies is the incorporation of many-electron correlation effects due to higher\u2013than\u2013two-body components of the cluster and EOM ex- citation operators, needed to achieve a quantitative description, without running into the usually prohibitive computational costs of the CC approach with singles, doubles, and triples (CCSDT) and its excited-state EOMCCSDT extension, the CC method with singles, doubles, triples, and quadruples (CCSDTQ) and its excited-state EOMCCSDTQ extension, etc., and without resorting to perturbative CCSD(T)-type ideas that fail in multireference situations, such as bond breaking and excited states dominated by two-electron transitions. One of the most promising approaches in this area is the semi-stochastic CC(P;Q) methodology that identifies the most important higher\u2013than\u2013doubly excited determinants needed in the high- level CC/EOMCC calculations with the help of the stochastic configuration interaction (CI) and CC Quantum Monte Carlo (QMC) wave function propagations and uses the suitably designed deterministic iterative and noniterative steps of the CC(P;Q) formalism to converge the desired CCSDT/EOMCCSDT, CCSDTQ/EOMCCSDTQ, etc., energetics. In this dis- sertation, we first discuss our recent work on extending the semi-stochastic, CIQMC-driven, particle-conserving CC(P;Q) framework to excited electronic states and open-shell systems. We tested performance of the resulting methods by examining their ability to recover the high-level CCSDT/EOMCCSDT energetics in calculations of the electronic excitation spec- tra of the CH+, CH, and CNC molecules and singlet\u2013triplet gaps in a few biradical systems, including methylene, (HFH) 12, cyclobutadiene, cyclopentadienyl cation, and trimethylen- emethane. The second part of this dissertation focuses on an alternative way of determining ground and excited states of open-shell systems within the EOMCC framework by turning to the single and double electron attachment (EA) and single and double ionization potential(IP) EOMCC schemes. By generating ground and excited states of open-shell species, such as radicals and biradicals, with the help of suitably designed operators that can formally add electrons to or remove electrons from the parent closed-shell cores (an operation pro- ducing the appropriate multi-configurational reference space within a single-reference frame- work, while relaxing the remaining electrons), the resulting EA/IP- and DEA/DIP-EOMCC methods offer several advantages over the particle-conserving CC/EOMCC treatments, in- cluding rigorous spin and symmetry adaptation of the calculated electronic states and the ability of handling high- and low-spin states in an accurate and well-balanced manner. We demonstrate how to utilize the stochastic CIQMC wave function propagations, which are of particle-conserving character, in identifying the dominant higher-order 3-particle-2-hole (3p- 2h)/3-hole-2-particle (3h-2p) and 4-particle-2-hole (4p-2h)/4-hole-2-particle (4h-2p) compo- nents of the respective particle-nonconserving electron attaching/ionizing operators, needed to obtain a quantitative description, without having to resort to the previously exploited user- and system-dependent active-space concepts. The effectiveness of the semi-stochastic, CIQMC-driven, EA/IP/DEA/DIP-EOMCC approaches will be illustrated by examining the adiabatic excitations in the C2N, CNC, N3, and NCO radicals and by revisiting the singlet\u2013 triplet gaps in methylene and trimethylenemethane.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
An Exploratory Study on Assessing Feasibility of Mass Timber and Its Alternatives in Construction : Total Cost of Ownership and Stakeholder Perspectives
No full textThesis (M.S.)--Michigan State University. Construction Management - Master of Science, 2024Recently there has been growing interest for using mass timber as a building material. Ithas been gaining momentum as an innovative alternative to traditional concrete and steel building methods, finding application in a growing array of construction projects ranging from mid to high rise buildings. Despite these efforts, developers/owners are still reluctant to choose mass timber as mainstream building material for the construction. Various significant barriers are faced by the community in migrating towards mass timber construction which majorly consists, lack of mass timber knowledge and case study projects which makes it difficult for the community to study the overall feasibility of the new construction method. This study aims to mitigate these barriers by conducting holistic exploratory study using total cost of ownership analysis for a 14 story 277749 sq. ft mass timber building to be constructed in Madison. To analyze the financial and economic impact of using mass timber as a building material, this study compares capital cost and total cost of ownership of functionally equivalent building design with alternative materials like hybrid steel/timber, concrete and steel. This would enable owners/developers to realize the impact of using mass timber as a viable construction method. It was realized that front end cost of mass timber was around 10% more costlier than concrete but it saved around 8.4% in longer term. Furthermore, we explore stakeholder interests through a qualitative and quantitative interview tailored to case study buildings, offering valuable insights into their inclinations and priorities. The insights gleaned from this thesis will provide valuable contributions to construction stakeholders, offering fresh perspectives on the use of mass timber building materials.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
MITIGATING FREEZE-THAW DAMAGE IN SOILS VIA PHASE CHANGE MATERIALS (PCM)
No full textThesis (M.S.)--Michigan State University. Civil Engineering - Master of Science, 2024Freeze-thaw (F-T) cycles cause significant frost heaving and thaw weakening in roadway subgrade soils. Frost heaving and thaw weakening occur only when there is available water, frost susceptible soil and temperature fluctuations around the freezing temperature of water. The goal of this study is to use Phase Change Materials (PCMs) to lower freezing temperature of soils and minimize the temperature fluctuations during F-T cycles. PCMs absorb and/or release high latent heat when they undergo a phase change. PCMs with the appropriate phase change temperature have the potential to reduce temperature fluctuations around the freezing/thawing point of soil, thereby helping reduce the damage inflicted by freeze-thaw cycles. In this study, three different types of PCMs were mixed with Glacial Till (GT) and Sandy Soil (SS). The PCM types were inorganic PCM (PCM-A), organic PCM (PCM-B), and PCM-B in powder form (pPCM-B). The characterization of PCM and soil-PCM mixture was determined by Atterberg limits, Harvard miniature compaction test, differential scanning calorimetry (DSC), scanning electron microscope (SEM) imaging, freezing point depression and PCM evaporation tests. DSC tests confirmed that the selected PCMs have high latent heat. Freezing point depression tests showed that PCM-B and pPCM-B freeze above the freezing point of water in soil, suggesting they would delay the freezing of soil. SEM images showed no change on the surface of soil-PCM mixtures compared to the control specimens, indicating no chemical reaction between soil and PCMs occured. PCM-B did not evaporate from the surface of soils for a 2-hour period at various environmental conditions. Based on characterization tests, PCM-B was selected as the best-performing PCM, and it was tested for further performance tests such as resilient modulus (MR), frost heave-thaw settlement tests. PCM-B did not cause an adverse effect on the MR of GT at different number of freeze-thaw cycles. PCM-B showed a good thermoregulation effect and slowed down the water migration in the frozen region of soil by reducing the permeability of the soils. Furthermore, after 2 F-T cycles, all soils with PCM-B achieved significantly lower heave rate, maximum heave and moisture content than control specimens. The results suggest that PCMs can be highly effective at mitigating freeze-thaw damage in subgrade soil.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
A NEW DIMENSION IN UROLOGY : ADVANCED 4D MODELING TECHNIQUES TO UNVEIL SEX-SPECIFIC BLADDER MECHANICS
No full textThesis (Ph.D.)--Michigan State University. Mechanical Engineering - Doctor of Philosophy, 2024Bladder health and dysfunction is not well understood. Research with mouse models is an effective way to study soft tissue/organ function especially with the genetic tools available in this species. Despite this advantage, bladder research in mice is still lacking compared to other animal models. Particularly, mechanical testing/analysis of the mouse bladder tissue are near non-existent in literature. In this dissertation, experimental ex vivo pressurization of whole mouse bladders was used to analyze the mechanical stresses and stretches in the soft tissue. Bladder filling cycles were digitally reconstructed in four dimensions (4D: 3D space + time). The reconstructions were used to characterize the geometry and mechanics of the bladder as it fills. This led us to the novel discovery that male and female bladder behaves in significantly different way, even in health. This work contributes to the bladder mechanics literature as this level of 4D and mechanical analysis of bladder filling in a mouse model has not been shown before.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
Network biology powered by graph deep learning : Understanding the molecular basis of human genetics
No full textThesis (Ph.D.)--Michigan State University. Computational Mathematics, Science and Engineering - Doctor of Philosophy, 2024Graph learning is revolutionizing the 25-year-old field of network biology by advancing our ability to gain novel molecular insights into biological functions and complex diseases using genome-scale molecular interaction networks. Earlier developed computational network biology methods are limited by their accuracy, scalability, and biological context-specificity. This thesis develops several effective and efficient graph learning methods to further our ability to uncover the multifaceted, complex, and context-specific roles of human genes.In living cells, biochemical and biomolecular entities, like protein, RNA, and DNA, intricately interact to exert and regulate biological functions and express molecular traits. This interconnected nature renders the network biology perspective, which models the intermolecular relationships as a graph, quintessential in understanding genes\u2019 biological roles. As a newly developed field rapidly evolving due to its versatility and broad applicability, graph learning aims to build powerful models that unravel complex interaction patterns to accurately classify node labels, opening exciting opportunities to understand human genetics.This thesis contributes toward a deeper understanding of human genetics using gene interaction networks by developing algorithms, methods, applications, benchmarks, and software. Specifically, through a comprehensive study using various biological networks and gene classification tasks, I first demonstrate that building machine learning models using the network adjacency matrix systematically achieves more accurate gene classifications compared to traditional network propagation-based approaches. Despite the superior performance, the proposed approach does not scale well to large and dense networks, hindering its applicability. To resolve this limitation, I next develop several effective and efficient graph representation learning methods and software by carefully considering the data characteristics of biological networks and the context-specific nature of biological systems. Finally, I consolidate a comprehensive resource for graph deep learning-based gene classification, allowing future developments to be easily built on top of the work done in this thesis.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
Three Essays on Matching Problems
No full textThesis (Ph.D.)--Michigan State University. Economics - Doctor of Philosophy, 2024This dissertation studies opportunity and equity in college admissions, as well as how higher education affects labor market outcomes. The first two chapters explore how state policies affect enrollment at public institutions of higher education. The third chapter characterizes outcomes in a labor market in which agents with different skill levels (levels of education) choose roles and match with each other. In each chapter, I build a theoretical two-sided matching framework to explore how limited opportunities are allocated, and motivate theoretical predictions with empirical evidence.Chapter 1: Performance Funding and Equity of Access to Public UniversitiesWhile state appropriations to public universities have historically been determined by student headcount (enrollment funding), an alternative is to fund based on completion metrics such as number of degrees conferred (performance funding). Advocates argue that performance funding incentivizes universities to decrease inefficient over-enrollment, while critics argue that performance funding incentivizes universities to admit fewer under-represented minority applicants, as they are less likely to graduate. I develop a framework in which a social planner and universities systematically differ in their expected returns to enrolling students and show that there exist many enrollment and performance funding rules that realign the university's enrollment problem with the social planner's problem. Ultimately, level of funding affects enrollment, not structure of the funding rule. I also identify conditions such that funding changes disproportionately affect under-represented minority enrollment. To assess theoretical predictions, I estimate changes in selectivity and demographic composition of incoming first-time, full-time cohorts at public four-year universities in Ohio and Tennessee, states that switched to performance funding in 2009 and 2010 respectively. Ohio decreased funding in the long-run, while Tennessee did not; as predicted, I find evidence of increased long-run selectivity in Ohio but not in Tennessee. I also find the proportion of Black enrollment in Ohio decreased by 1.13 percentage points in the long-run, while it increased by 2.93 percentage points in Tennessee.Chapter 2: The Enrollment Effects of Regional CampusesThe Ohio public university system has several institutions, including its flagship Ohio State University (OSU), that are split between ``main'' and ``regional'' campuses. While OSU's regional campuses are independently accredited institutions, they also have a strong transfer function: if a regional campus student has a minimum 2.0 GPA and 30 credit hours, they are guaranteed the option to transfer into the main campus. I build a general theoretical framework of first-time and transfer admissions with multiple institutions; the theory predicts that opening a regional campus causes community colleges to enroll a less academically prepared first-time student body, and may cause community college students to be crowded out by less prepared regional campus students in transfer admissions. As such, there are always both students who are strictly better and worse off after a regional campus opens, and opening a regional campus is not always welfare increasing. I show that a social planner prefers to modestly expand enrollment at a main campus over opening a larger regional campus if the regional campus is insufficiently differentiated from a community college.Chapter 3: Choosing Sides in a Two-Sided Matching MarketI model a competitive labor market in which agents of different skill levels (e.g., college educated or not) decide whether to enter the market as a manager or as a worker. After roles are chosen, a two-sided matching market is realized and a cooperative assignment game occurs. There exists a unique rational expectations equilibrium that induces a stable many-to-one matching and wage structure. Positive assortative matching occurs if and only if the production function exhibits a condition that I call role supermodularity, which is stronger than the strict supermodularity condition commonly used in the matching literature because a high skilled agent with a role choice is only willing to enter the market as a worker if she expects that it is more profitable to cluster with only other high skilled agents than to exclusively manage. The wage structure in equilibrium is consistent with empirical evidence that the wage gap is driven both by increased within-firm positive sorting as well as between-firm segregation.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
Follower Reactions to Leader Emotional Displays Depend on Affective Values
No full textThesis (Ph.D.)--Michigan State University. Business Administration - Organization Behavior - Human Resource Management - Doctor of Philosophy, 2024Scholars have long sought to understand how the emotional displays of leaders make an impact on their followers at work. Much of this literature has emphasized that followers respond favorably to leaders displaying excitement, as these emotions are believed to be highly desired by followers and hence capable of inciting follower behavior at work. However, research has made the implicit assumption that followers are equally predisposed to excitement, while leaving it uncertain how the affective values of followers play a role in shaping follower reactions to leaders at work. To bridge this gap, I suggest that followers vary in their affective values, such that followers differ in their preferences towards high activation positive emotions (e.g., excitement) and low activation positive emotions (e.g., calm). Subsequently, when a follower\u2019s affective values align with the emotion displayed by their leader, I posit that the follower will experience greater emotion in response to their leader\u2019s displays and in turn, exhibit greater behavior (e.g., goal progress) at work. In contrast, a mismatch between a follower\u2019s affective values and the leader\u2019s emotional display will lead to diminished emotional reactions in the follower, lowering the extent to which the leader can shape their follower\u2019s behavior. Results from an experience sampling study provide support for most of these predictions. Altogether, I demonstrate that follower reactions to leaders depend on affective values, such that not every follower wants an exciting leader at work.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
GENDER, POWER, AND TRANSFORMATION IN RURAL DEVELOPMENT IN LATIN AMERICA
No full textThesis (Ph.D.)--Michigan State University. Community Sustainability-Doctor of Philosophy, 2024Gender equality in low-income and middle-income countries (LMICs) has been a development goal since the 1990s. Although progress has been made in reducing gender gaps, gender inequalities, mostly against women, persist. In rural and agricultural settings in LMICs, women have less decision-making authority over arable land, less access to agricultural inputs, and more poverty time \u2013deprivation of free time or leisure due to unpaid and paid labor activities-- compared to their male counterparts. Therefore, Sustainable Development Goal 5 on Gender Equality is far from being accomplished by 2030, as agreed in 2016 by the international community.Therefore, scholars and practitioners in gender and development are calling for the urgency of transforming one of the main roots of gender inequalities: the gender structures of constraint (gender norms and rules). However, little has been done to understand the how of that transformation. This dissertation includes one theoretical and two empirical research articles. It delivers insights into the gender and development literature on transformation and recommendations to development practitioners. The first article proposes a theoretical framework for gender and development scholars and practitioners to examine gender structure transformations amid implementing development programs in LMICs. This framework integrates the literature on rural women\u2019s empowerment in the Gender and Development (GAD) school of thought and Feminist Political Ecology (FPE). In this article, I compare the concepts of gender, power, and transformation in both literatures and propose the Women\u2019s Empowerment for Gender-Transformative Development Framework. The second article implements the theoretical framework proposed in the first article. The objectives of this article are a) to examine how women and men challenge gender norms when they receive resources from a development program; and b) to identify the potential negative consequences when women and men challenge norms due to their participation in the program. To do that, I implement a content analysis from 65 semi-structured interviews with rural women and men participating in Empropaz, a nationwide entrepreneurship program with a gender focus in Colombia. The results show that women and men challenged gender norms by enhancing their self-esteem, sense of agency, control over resources, and family cooperation. However, collective power was less prevalent. The resources provided by Empropaz enabled individuals to have new thoughts and perform new actions that defied traditional gender expectations. Despite these gains, a few participants continued to experience verbal gender-based violence, heightened family conflict, and decreased life balance. The third article is an in-depth intra-household analysis of gendered dynamics. It provides evidence of the role of power legitimacy for women having decision-making authority over agricultural land. Based on GAD literature, it identifies the association of power legitimacy and other social factors (e.g., access to land and education) in explaining spousal discord or accord on who within the household makes decisions over the land. The study\u2019s objectives are: a) to understand women\u2019s participation in decisions within the household, both domestic and agricultural, compared to their male counterparts; b) to identify the role of legitimacy factors in determining women\u2019s participation in agricultural decisions; c) to identify the role of other social factors in determining women\u2019s decision; and d) to identify the role of legitimacy factors in women\u2019s and men\u2019s discord in their survey\u2019s responses. I implemented a firth logit and a multinomial logistic regression based on an intra-household survey (responded by the woman and man head of the household separately) with 147 households producing cashews in Honduras. The results show that a legitimacy factor \u2013 the women feeling comfortable having different opinions with their male partner \u2013 positively and significantly affects women\u2019s decision-making authority. Similarly, land ownership, contribution to on-farm labor in cashew production, participation in other crops and animals, and having more education than their male counterparts positively and significantly affect women\u2019s decision-making authority over cashews plots. The aforementioned legitimacy factor is also positively associated with women and men having the same opinion that women participate in the decisions over the land. The dissertation concludes that it is important for rural development to support women and men in challenging gender norms, and for couples to address conflicts and differing opinions, to achieve SDG 5 in Latin America. Research that merges GAD and FPE can highly contribute to this endeavour.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
Identities in Negotiation : Stories from Three Transnational Multilingual Asian Writing Teachers
No full textThesis (Ph.D.)--Michigan State University. Rhetoric and Writing - Doctor of Philosophy, 2024This dissertation project investigates the lived experiences of three transnational multilingual Asian writing teachers across transnational trajectories to understand how these teachers negotiate their identities within sociocultural, institutional, and ideological structures. Addressing the underrepresentation of transnational multilingual teachers in Rhetoric and Writing, this project seeks to uncover the mechanisms that render these teachers invisible in the field and to make their everyday power struggles in negotiating their identities visible. Employing a story-centered qualitative research approach, including autoethnography and narrative case studies, this project interweaves stories from myself and two teacher participants. As a result, this project creates a more comprehensive and nuanced picture of transnational multilingual teacher identities. Specifically, the results of this project indicate that transnational multilingual teachers fluidly negotiate their hybrid identities to move between the systems of power, constantly reconceiving, remixing, and transforming who they are, drawing on their developed transnational, translingual, and rhetorical competencies. This project has implications for research and writing program administration to move toward greater visibility of transnational multilingual writing teachers in the field.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references