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Obscure Variables in Battery Research: Impacts of Spacer Thickness and Slurry Formulation Protocols
Get PDFThesis (Master's)--University of Washington, 2025While much battery research focuses on new materials and full-cell designs, early-stage battery evaluation still relies on small, lab-scale coin cells, where often-overlooked factors can significantly affect test results. This work investigates two critical yet underexamined aspects of electrode performance: cell pressure and slurry formulation. First, the impact of spacer thickness, and thus internal cell pressure, on the electrochemical performance of sodium-ion coin cells is examined using hard carbon anodes. Findings show that insufficient compression leads to unstable contact, reduced capacity, and greater variability, while greater compression promotes higher capacity and greater cycle stability. Theories explaining these findings are discussed. Second, the optimization process of aqueous slurry mixing for hard carbon electrodes is presented. The sources of particle agglomeration and slurry inconsistency are found, ultimately developing a reliable protocol that improves coating uniformity and slurry stability
An Examination of Migration Trends out of Africa Through the Lens of African Immigrants in Pierce County, Washington
Get PDFBachelor of arts (BA)Each year over a million immigrants from all over the world enter the United States to pursue opportunities for education, employment, and to escape oppressive regimes to start a new life. Recent federal Executive Orders, and legislative attempts to remove immigrants have renewed public interest on the topic. Much of this attention on immigration is on our southern border and the effects of U.S. policy and practice on Latino/Latinx individuals, despite similar impacts on African immigrant communities in the U.S. This paper turns attention to the forces that are contributing to migration out of Africa, such as climate change, terrorism, poor economic opportunities, and poorly managed governments. It also aims to explore the experiences of African immigrants in Washington state and, more specifically, to determine if there are institutional systems that are failing or missing in Pierce County, Washington. Grounded in broader research related to African migration trends, this paper describes results from a mixed-method study that analyzes data from demographic surveys and oral interviews with African immigrants in Pierce County, Washington, to better understand the experience African immigrants have when they reach the U.S. and explores how to address a lack of programs and resources to support local African immigrant communities
Acceptability of same-day HIV pre-exposure prophylaxis initiation among individuals with depression symptoms during emergency care in Nairobi, Kenya.
Get PDFThesis (Master's)--University of Washington, 2025University of WashingtonAbstract
Acceptability of same-day HIV pre-exposure prophylaxis initiation among individuals with depression symptoms during emergency care in Nairobi, Kenya. IntroductionHIV pre-exposure prophylaxis (PrEP) is an important prevention strategy, but its integration into routine care faces challenges, especially in low- and middle-income countries. Emergency departments (EDs) present a unique, yet underutilized, opportunity for PrEP delivery, particularly for people with less access to care or who are marginalized and face challenges accessing care, such as those from key populations. Emergency care utilization is high among people with depression and may influence health decision-making, including PrEP uptake. This study aimed to determine the acceptability of same-day PrEP initiation among ED patients with varying depression severities and identify associated patient-level factors. The hypothesis was that patients screening positive for moderate to severe depression would be less likely to accept same-day PrEP than those with screening scores consistent with a lower risk of depression due to the potential impact of depression-related cognitive impairment on health decision-making.
Methods
This cross-sectional study utilized secondary data from the ED-PrEP study, conducted from July 5, 2024, to August 18, 2024, at the ED of Kenyatta National Hospital in Nairobi, Kenya. 1 The study population included 295 adult ED patients (aged ≥18) who were not critically ill or pregnant and had a Patient Health Questionnaire 9 (PHQ-9) scores of 1 or higher. The primary outcome was the acceptability of same-day PrEP initiation, defined as willingness to start PrEP if eligible. Depression severity was the primary exposure, categorized by PHQ-9 scores: minimal to mild (scores 1-8), moderate (scores 9-14), and moderately severe to severe (scores 15-27). Statistical analysis was conducted using chi-square tests, simple, univariate, and multivariate logistic regression to calculate unadjusted and adjusted odds ratios (aOR) with 95% confidence intervals (CI), adjusting for sociodemographic and behavioral confounders.
Results
Of the 295 participants analyzed, 46% had minimal to mild depression, 39% moderate, and 15% moderately severe to severe depressive symptoms. Willingness to initiate same-day ED-PrEP was high across all groups: 76.3% (minimal to mild), 76.5% (moderate), and 84.4% (moderately severe to severe). There was no statistically significant association between depression severity and PrEP acceptability. However, being unmarried (aOR=2.93, 95% CI: 1.42-6.06), reporting consistent condom use (aOR=3.72, 95% CI: 1.22-11.34), knowing a partner's HIV status (aOR=2.07, 95% CI: 1.18-3.64), and experiencing intimate partner violence (IPV) (aOR=2.34, 95% CI: 1.15-4.76) were significantly associated with higher PrEP acceptability.
Conclusions
Depressive symptom severity did not influence the acceptability of same-day PrEP initiation among ED patients in Nairobi. The high overall PrEP acceptability highlights the feasibility of integrating PrEP services into the emergency departments. Factors such as marital status, condom use, awareness of partner HIV status, and history of IPV were strong predictors of PrEP acceptability. These results underscore the importance of comprehensive, person-centered approaches in EDs that address both HIV risk and co-occurring vulnerabilities like IPV, to effectively improve PrEP uptake in high-burden setting
Study of Fracture Toughness and Notch Toughness under Impact loading of Electron Beam Melted Ti-6Al-4V alloy
Get PDFThesis (Master's)--University of Washington, 2025This thesis presents a comprehensive investigation into the fracture toughness and the notch toughness behavior of Electron Beam Powder Bed Fused (EB-PBF) Ti-6Al-4V alloy, with particular focus on the effects of build orientation, key mechanical properties and microstructural characteristics. Vertical compact tension specimens as well as Horizontal and vertical Charpy Impact specimens were fabricated using optimized processing parameters. Notch toughness was evaluated using instrumented Charpy impact tests, while fracture toughness was measured using linear-elastic fracture mechanics on fatigue-precracked specimens. The fracture surfaces were examined using profilometry, scanning electron microscopy, microhardness measurements, and microstructural analysis. The findings were correlated with the mechanical properties of similarly fabricated specimens under identical conditions.Vertical specimens demonstrated superior toughness performance across both test regimes. In fracture toughness testing, Y-Z specimens exhibited the highest toughness (65.81 MPa√m), while X-Z showed the lowest (63.10 MPa√m). Post-machining generally improved toughness values by mitigating surface defects and enhancing crack resistance. In impact testing, vertical specimens absorbed ~50% more energy than horizontal specimens due to greater ductility, lower microhardness, and crack propagation paths that intersect prior-β grains more frequently. Surface profilometry confirmed ~35% higher shear lip heights, ~50% larger shear areas, and ~15% rougher cracking regions in vertical specimens, indicating increased plastic deformation. The study highlights the critical role of build orientation and post-processing in tailoring the toughness of EB-PBF Ti6Al4V, offering valuable guidance for design and qualification of AM components in structural applications
How Standards Solve the Problems of Supply Chain Disintegration for Interdependent Technologies
No full textThesis (Ph.D.)--University of Washington, 2025Why do firms coordinate to create technology standards? While prior scholars have largely focused on the role of technology standards in facilitating interoperability to enhance network effects, none have focused on the role of standards in coordinating and diffusing co-specific innovation. From this perspective, interoperability standards address two tiers of a nested problem of asset co-specificity. At the component stage, modularity erodes asset specificity in supply chains and networks. At the standard creation stage, the contractual obligations embedded in technology standards limit opportunism between contributors, allowing them to create co-specific intellectual property without fear of hold-up. I demonstrate this logic with a formal model, and explore nuances and implications in case studies of Nvidia and Apple. I also evaluate robust empirical evidence. Using a difference-in-differences design, I find that standards tend to greatly reduce litigation over standard-essential intellectual property. Finally, I attempt to adjudicate between theories of merit-based idea selection and rent-seeking in standard setting processes and in SEP declarations. While results on idea selection are inconclusive on both sides, evidence suggests that SEP declarations are based on merit and heuristics, and are not driven by rent-seeking
Pigeon Guillemots as a Model of Maritime Urban Adapters
Get PDFAs the human population surpasses 8 billion and development encroaches at the edges of remaining wild areas, wildlife and humans are increasingly finding themselves in conflict for the same resources and, at times, even space. In the face of the sixth mass extinction, many species are being pushed to the edge of their tolerance of human presence. A paradigm has been introduced to describe three prominent categories of wildlife response to urban encroachment: urban avoiders, which cannot adapt to habitat significantly altered by humans, urban adapters, which may frequently occupy habitat overlapping with human use, and urban exploiters, which are primarily or exclusively found in conjunction with human populations (Rodewald & Gehrt 2014). Persisting in altered urban environments may place certain species under highly specific and amplified selective pressures that could alter their behavior and morphology over a short period of time (Marzluff 2012)
Numerical Evaluation of Code Requirements and Nonlinear Performance of Torsionally Irregular Structures
No full textThesis (Ph.D.)--University of Washington, 2025Structures with torsionally irregular configurations – those with non-coincident centers of mass, stiffness, and strength – are vulnerable to amplified seismic demands from twisting modes of response that localize deformation and damage, increasing the likelihood of failure or collapse during strong ground shaking. Despite decades of research, design provisions for torsional irregularity remain inconsistent across international codes and are often based on studies of reduced-order models that may not adequately capture the behavior of multi-story or spatially irregular systems. To address these perceived gaps, this dissertation leverages high-performance computing to investigate the design and behavior of torsionally irregular structures through three interconnected studies: (1) Minimizing superstructure twist in irregular bridges through optimization of structural parameters (2) Evaluation of design provisions in the New Zealand seismic design standard (NZS 1170.5:2004) for the seismic assessment of torsionally irregular buildings, and (3) Improving the seismic performance of torsionally irregular buildings using force-limiting diaphragm connections. The first study investigates geometrically irregular bridges using a validated finite element model of a previously tested reinforced concrete bridge. It evaluates three modification strategies: adjusting column effective heights, altering end fixity conditions, and redistributing superstructure mass, to reduce torsional response. Numerical and optimization-based studies showed that increasing the effective stiffness of columns by reducing their effective height was the most efficient strategy. The study also demonstrated that a small subset of hazard-consistent ground motions could capture the essential behavior required for optimization, providing a practical balance between computational efficiency and accuracy. The second study examines torsionally irregular buildings within the context of the New Zealand seismic design standard (NZS 1170.5:2004). Reinforced Concrete Shear Wall (RCSW) and Steel Special Moment Frame (SSMF) buildings were designed and analyzed using nonlinear time-history simulations of site-specific ground motions derived from the 2022 New Zealand National Seismic Hazard Model. A comparative analysis of the current code provisions and proposed updates by a working task group showed that the proposed updates substantially reduced maximum drift demands and collapse probabilities, especially for highly ductile SSMF systems, while penalizing designs with excessive torsional irregularity. The third study explores the potential of deformable Inertial Force-Limiting Connections (IFLC) to reduce seismic demands in irregular buildings. By replacing conventional rigid diaphragm-to-lateral system links with deformable connections designed to dissipate energy and limit force transfer, the study established rational benchmarks for connection stiffness and strength based on diaphragm design forces and system drift constraints. Results indicated that properly tuned IFLCs can reduce lateral force demands, making them a promising design option for improving the seismic resilience of irregular structures. Overall, the findings of this dissertation improve our understanding of torsionally irregular structural systems through code-level evaluations employing advanced numerical modeling techniques and the examination of innovative connection strategies through numerical optimization. The results provide a rational basis for updating national seismic design standards and highlight the potential of force-limiting methods as a next-generation seismic design tool for irregular structures
Novel single-cell genomic approaches for deciphering cellular heterogeneity
No full textThesis (Ph.D.)--University of Washington, 2025Single-cell genomics has reshaped our understanding of developmental biology by uncovering intricate molecular states at unprecedented scale. However, continued development of experimental and computational approaches is needed to fully realize its potential. In this dissertation, I will introduce three distinct projects, each centered around adapting computational tools or developing novel experimental approaches to decipher cellular heterogeneity. In the first project, we adapted latent Dirichlet allocation to single-cell combinatorial indexed Hi-C (sci-Hi-C) intra-chromosomal contact maps to decompose the data into chromatin topics. Our approach enabled co-embedding and clustering of sci-Hi-C data derived from five different cell lines (GM12878, H1Esc, HFF, IMR90, and HAP1) and identification of cell type-specific topics of chromatin interactions. In the second project, we developed inexpensive spike-in controls for single-cell combinatorial indexed RNA-seq (sci-RNA-seq) experiments using a set of single-stranded hash oligonucleotides (“hash ladder”). To normalize for technical variation introduced within individual cells, we calculated a cell-specific size factor that is derived from the hash ladder. We applied the ladder to study the effects of various chemical perturbations, including RNA pol II elongation, histone deacetylation, and activation of the glucocorticoid receptor. In the third project, we vastly improved Visual Cell Sorting (VCS), which is an automated imaging workflow that enables binning and sorting of cells by visual phenotypes, by making it compatible with cell fixation and three-level sci-RNA-seq (sci-RNA-seq3). We applied VCS to sort over one million E15 F1 B6xCAST mouse embryo derived nuclei based on nucleolar and nuclear speckle size, and we profiled the sorted nuclei with sci-RNA-seq3. We revealed differences in these nuclear compartment sizes within and across cell types and identified both expected and unexpected correlations with proliferation and differentiation status. We identified 42 genes that positively correlated with relative nucleolar size, reflecting the activation of gene expression programs relating to ribosomal biogenesis and proteostasis stress response. Finally, we demonstrated that these genes can be used to quantify relative nucleolar size across mouse, human, and zebrafish developmental atlases
Depressed and Drinking: A Daily Diary Study of Mood, Alcohol, and Behavioral Activation
No full textThesis (Ph.D.)--University of Washington, 2025Young adults, compared to other age cohorts, are more likely to develop and experience depression and alcohol use disorders, singly or concurrently. Some interventions, including behavioral activation, have shown promise as potential concurrent treatment models for these concerns. Studies examining theorized behavioral activation treatment mechanisms alongside alcohol consumption and related factors, especially across multiple timepoints, are limited. We hypothesized that increased alcohol consumption (across timepoints) would be predicted by increased depression symptomatology, alcohol-related problems, and drinking to cope, as well as by decreased engagement with theorized behavioral activation treatment mechanisms. The current study (N = 109) explores these behavioral activation-, depression-, and alcohol-related factors in a college student sample through 22 daily online surveys. Results: alcohol-related problems and engagement with behavioral activation targets were both associated with alcohol consumption at baseline and only alcohol-related problems were predictive in longitudinal models of daily alcohol consumption, while in the weekly model, only the previous week's alcohol consumption and previous week's alcohol-related consequences were significant. These findings help to extend our understanding of the relation between depression, behavioral activation targets, and alcohol, and may help to refine mHealth or other interventions for this population
Development and Validation of a Modular, Realistic IV Placement Training Model (PractIV)
Get PDFThesis (Master's)--University of Washington, 2025This thesis presents the development of PractIV, a modular peripheral intravenous (PIV) training simulator designed to improve realism, adaptability, and integration of IV placement training for healthcare professionals. The research project is a collaboration with the University of Washington (UW) Mechanical Engineering 'Engineering in Health' (EIH) Program, and the Center for Research in Education and Simulation Technologies (CREST) at UW. The goal of this work is to develop a modular IV arm trainer specifically designed to comply with the Modular Healthcare Simulation and Education System (MoHSES™) physical connection standards, enabling seamless integration with existing manikins such as the Advanced Joint Airway Management System (AJAMS), Both previously developed by CREST. PractIV addresses key limitations in existing IV training tools, which often lack anatomical realism and fail to prepare learners for challenging patient scenarios. By combining insights from clinical practice, mechanical design, and additive manufacturing, this work contributes to the fields of medical simulator development and IV training