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Jetting dynamics of bursting bubbles coated with protein–surfactant or polymeric compound layers
No full textSubmission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2025-10-19 without embargo termsThe student, Sainath Barbhai, accepted the attached license on 2025-05-05 at 12:38.The student, Sainath Barbhai, submitted this Thesis for approval on 2025-05-05 at 21:29.This Thesis was approved for publication on 2025-05-08 at 15:59.DSpace SAF Submission Ingestion Package generated from Vireo submission #22208 on 2025-10-19 at 18:12:39Bursting of bubbles can be observed in a wide range of natural and industrial processes. The production of drops via bursting jets plays a critical role in the mass transport of chemical and biological contaminants, influencing scenarios from global climate dynamics to disease transmission. While the jetting dynamics of clean bubble bursting have been extensively studied over the past decade, real-world scenarios often involve contaminated bubbles. Due to their scavenging nature, bubbles frequently accumulate various contaminants that can potentially alter the jetting behavior and making it essential to understand the presence of surface/compound contamination. This thesis presents experimental investigations into bubble bursting at contaminated interfaces, focusing on viscoelastic surfaces composed of proteins, protein–surfactant mixtures, and polymeric coatings that mimic real-life contaminants. The objective is to understand how these rheologically complex interfacial layers alter jetting dynamics and influence drop ejection behavior. The first part of this thesis investigates the effect of surface viscoelasticity on top jet drop formation during bubble bursting. Specifically, we examine interfaces composed of globular proteins and mixed protein–surfactant solutions across a range of concentrations and controlled aging times. Our results show that the surface viscoelasticity imparted by these surface-active species significantly alters the jet ejection dynamics. This previously underexplored behavior highlights the distinct physicochemical properties of proteins and surfactants at the bubble interface that give rise to different interfacial stress responses, ultimately influencing jet formation mechanisms. Our findings may improve insight into the dynamics of bubble bursting on contaminated surfaces and highlight how surface viscoelastic properties influence aerosol generation. The second part of this thesis examines the influence of a polymeric compound layer on bubble bursting dynamics by systematically varying the compound layer volume fraction and polymer concentration. We investigate their effects on cavity collapse and subsequent jet formation. Our findings reveal that higher compound volume fractions lead to the generation of faster and more slender jets, attributed to enhanced damping of capillary waves and a reduction in the cavity cone angle during jet initiation. In contrast, increasing the polymer concentration introduces significant viscoelastic resistance, resulting in reduced jet velocities and suppression of drop formation. These discoveries may shed light on the underlying mechanisms of organic material transport through bubble-driven aerosolization, contributing to a deeper understanding of marine biological processes and environmental dynamics
Investigation into alignment of carbon nanotubes within bulk materials printed from aqueous dispersions
No full textSubmission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2025-10-19 without embargo termsThe student, Judith Hutson, accepted the attached license on 2025-05-06 at 15:25.The student, Judith Hutson, submitted this Thesis for approval on 2025-05-06 at 15:47.This Thesis was approved for publication on 2025-05-08 at 15:27.DSpace SAF Submission Ingestion Package generated from Vireo submission #22223 on 2025-10-19 at 18:13:06Carbon nanotubes (CNTs) have excellent thermal and electrical conductivity, as well as exceptional tensile strength. Thus far, however, translating these properties to a bulk material has proved challenging, as the junctions between individual CNTs are a limiting factor in the material's performance. Maximizing conductivity therefore requires minimizing both the concentration of inter-tube junctions and the resistance of those junctions. The former can be mitigated to an extent simply by increasing nanotube length, but this comes with difficulties in growth and material fabrication and does nothing for the latter issue. Improving alignment, however, addresses both issues, allowing charge to travel further in one direction between junctions and maximizing inter-tube contact lengths to reduce resistance. Because carbon nanotube alignment is so beneficial, a great number of approaches exist. This work endeavors to introduce the major alignment methods and describe avenues of alignment measurement and quantification, allowing for a methodical approach to the issue
KL divergence – based disagreement sampling for multi-fidelity Bayesian optimization
Get PDFSubmission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2025-10-19 without embargo termsThe student, Abhishek Iyer, accepted the attached license on 2025-05-08 at 18:08.The student, Abhishek Iyer, submitted this Thesis for approval on 2025-05-08 at 18:13.This Thesis was approved for publication on 2025-05-09 at 12:15.DSpace SAF Submission Ingestion Package generated from Vireo submission #22271 on 2025-10-19 at 18:13:57Computational costs have increased tremendously over time owing to the increase in complexity of design. The motivation to reduce costs has led to the adoption of multi-fidelity optimization techniques. Active Learning has gained prominence as a sampling method which allows for maximum optimization of the design problem while utilizing minimal available data, consequently decreasing the cost of computation. This thesis proposes a novel KL-Divergence sampling strategy which iteratively makes use of fidelities to sample through a design space to optimize according to a target objective. This method was evaluated using the Rastrigin function and then applied on a design space consisting of 4-digit NACA airfoil combinations. It is observed that the KL divergence method provided a better optimization result compared to the Least Confidence method while simultaneously reducing reliance on information from higher fidelities. The disagreement sampler iterated over the airfoil design space and provided a better result as compared to the Least Confidence method
Optimal control-based mission simulation using accelerated automatic differentiation
Get PDFSubmission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2025-10-19 without embargo termsThe student, Akshaansh Chilakapati, accepted the attached license on 2025-05-08 at 23:25.The student, Akshaansh Chilakapati, submitted this Thesis for approval on 2025-05-08 at 23:37.This Thesis was approved for publication on 2025-05-09 at 11:56.DSpace SAF Submission Ingestion Package generated from Vireo submission #22280 on 2025-10-19 at 18:14:01Aerospace mission simulation and optimization present a variety of challenges that stem from their requirement to account for multiple facets. This thesis explores the use of modern, accelerated automatic differentiation in enhancing the solving and optimization of various aerospace problems posed as nonlinear optimal control problems. The growing complexity of aerospace systems and the limitations of traditional optimization workflows motivated the generalization of problem formulation, through the development of a JAX-based framework that efficiently implements and solves these optimal control problems through accelerated gradient-based optimization. After reviewing the theoretical foundations of optimal control and analyzing the role of gradients in optimization, the benefits of automatic differentiation are outlined, with the discussion of several state-of-the-art frameworks for the same. Through the modeling, discretization and optimization of 3 verifiable canonical problems - the Van der Pol oscillator, rolling disk, and free-flying robot - the direct transcription approach coupled with SciPy's Sequential Least Squares Quadratic Programming (SLSQP) solver is determined to be the most efficient problem setup. Then, JAX's automatic differentiation capabilities are implemented to enable fast and reliable computations of objective function and constraint gradients. A thorough comparison is drawn between the analytical and automatic gradient computations to cement the benefits of using JAX's capabilities and GPU-based optimization framework. The research is not centered around any one aircraft mission model or problem, but aims to generalize the application of the AD-based method. The future objective is to apply this to an RCAIDE mission framework that can simulate the operation of various types of aircraft. It is sought to prove that any problem can be optimized through the formulation of an objective function that covers all bases, with the implementation of JAX leading to huge cuts in computational time and overhead. Through the obtained results, we demonstrate that the JAX + SciPy SLSQP workflow achieves consistent convergence on problems ranging from simple to complex, offering a scalable and robust automatic differentiation framework for future aerospace mission optimization
Engineering the fusion machinery core of SARS-CoV-2 spike protein for vaccine immunogen design
Get PDFSubmission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2025-10-19 without embargo termsThe student, Timothy James Tan, accepted the attached license on 2025-02-11 at 11:43.The student, Timothy James Tan, submitted this Dissertation for approval on 2025-02-11 at 11:46.This Dissertation was approved for publication on 2025-02-13 at 16:22.DSpace SAF Submission Ingestion Package generated from Vireo submission #21613 on 2025-10-19 at 18:17:14The emergence and spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in 2019 prompted the rapid development and deployment of vaccines harboring the spike protein of the virus. For vaccines to be effective, the spike protein immunogen required engineering into its prefusion-stabilizing conformation to elicit protective antibodies that primarily bind the spike receptor-binding domain (RBD), in addition to the spike’s N-terminal domain, and fusion machinery core. I showed that natural SARS-CoV-2 infection or vaccination with SARS-CoV-2 spike protein elicits protective, public antibodies encoded by IGHV3-53/3-66 with unique amino acid sequence signatures. Eliciting these public RBD antibodies is an alluring goal of vaccination for prophylactic protection among majority of the human population. To this end, I developed a systematic and unbiased high-throughput method of identifying prefusion-stabilizing mutations in the fusion machinery core of SARS-CoV-2 spike protein that will render the RBD intact. By combining saturation mutagenesis, mammalian cell display, a cell-based fusion assay, fluorescence-activated cell sorting, and deep sequencing, I identified several mutations, in addition to the two proline mutations used in currently approved vaccines, that lock the spike protein in its prefusion conformation. Biophysical characterization revealed that a D994Q mutation in the first heptad repeat prevented the complete unfolding of the spike trimer by forming an additional intra-protomer hydrogen bond. To develop vaccines that can target future variants, escape mutants of the spike protein need to be identified and characterized. Public antibodies encoded by IGHV1-69 and IGKV3-11 target the highly conserved S2 subunit containing the fusion machinery core of SARS-CoV-2. However, deep mutational scanning experiments showed that the D950N and Q954H mutations found in Delta and Omicron variants, respectively, weaken the binding of public antibodies to spike, and consequently, decrease protection in vivo. These results highlight that an innovative, high-throughput, deep mutational scanning-based method can accelerate vaccine immunogen engineering by systematically interrogating each mutation, and antigenic drift of immunogenic proteins provide a significant challenge for the proactive development of universal vaccines
Exploring the biological embodiment of historical trauma and migration in South Asian immigrants to the United States of America
No full textSubmission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2025-10-19 without embargo termsThe student, Sana Saboowala, accepted the attached license on 2025-04-16 at 17:44.The student, Sana Saboowala, submitted this Dissertation for approval on 2025-04-16 at 17:50.This Dissertation was approved for publication on 2025-04-18 at 16:22.DSpace SAF Submission Ingestion Package generated from Vireo submission #21805 on 2025-10-19 at 18:18:22My work combines critical theory with scientific methods to better understand human health and strive towards health equity. My dissertation research uses oral histories and molecular methods to explore how lived experiences can be biologically embodied. Specifically, I focus on how historical, intergenerational trauma stemming from the multiple partitions of British India and subsequent migration-related stress impact South Asian immigrants to the United States. Through this project I explore how colonial science continues to impact communal violence in South Asia and the diaspora, use oral histories to discuss how stress and migration operate in intergenerational narratives, and combine oral histories with epigenetic methylation data to understand how historical trauma may be biologically embodied, with a focus on stress, diabetes, and heart disease. I analyzed twenty-five oral histories from the 1947 Partition Archive, a global digital archive focused on preserving oral histories with witnesses of the 1947 Partition. I also conducted oral histories with the generation after the 1947 Partition; I interviewed thirteen South Asian immigrants to the United States whose parents were alive during the 1947 Partition. I am working with the South Asian American Digital Archive (SAADA) to archive those oral histories. I analyzed all thirty-eight oral histories in parallel, focusing on themes that emerged from narratives of stress and migration. To understand the biological embodiment of these experiences, I looked at methylation patterns, screening over 850,000 sites genome wide, in the thirteen South Asian immigrants to the United States that I interviewed. Due to COVID-19 restrictions, I developed a successful mail-in method that participants used to self-collect dried blood spots, from which I extracted DNA and RNA. Using the oral histories, I created contextual variables focused on affect, including factors like “expressions of gratitude” and “narratives of intergenerational loss.” I also used the oral histories to adapt survey measures on historical trauma to fit the South Asian context. I characterized associations between these variables and DNA methylation of genes associated with stress response (glucocorticoid receptor and hypothalamic pituitary adrenal axis function), diabetes, and cardiovascular disease. I found significant association between migration distress, as defined ii by the oral history research and a CpG site associated with atherosclerosis. The goal of the project was to consider how humanistic research can shape our understandings of the body, and to model how we can ask scientific questions differently
A geometric description of the heat kernel of the Witten Laplacian and the Cheeger-Müller theorem
Get PDFSubmission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2025-10-19 without embargo termsThe student, Karthik Vasu, accepted the attached license on 2025-04-18 at 11:32.The student, Karthik Vasu, submitted this Dissertation for approval on 2025-04-18 at 11:36.This Dissertation was approved for publication on 2025-04-18 at 15:56.DSpace SAF Submission Ingestion Package generated from Vireo submission #21832 on 2025-10-19 at 18:18:26In 1935, Reidemeister introduced the Reidemeister torsion, an invariant on cochain complexes with fixed basis. These invariants were used to distinguish homotopy equivalent manifolds that are not homeomorphic. Ray and Singer in 1971, introduced an analytic analogue of the torsion on smooth manifolds, the Ray-Singer analytic torsion. They noticed these two torsions exhibit similar properties and conjectured that they must be equal. The conjecture was proved independently by Cheeger and Müller in 1979. Later in 1994, Bismut and Zhang introduced a new proof of the Cheeger-Müller theorem using the heat kernel of the Witten Laplacian. The proof was based on the study of the asymptotic expansion of the heat kernel. In this thesis, we provide a geometric description of the heat kernel of the Witten Laplacian by using Melrose’s blow up techniques. We construct a blown up heat space and show that the heat kernel is polyhomogeneous on it. We then use Getzler’s rescaling argument to get a explicit expression for the anomaly term when the representation is not unimodular
Exploring motivation to lead: Insights on student leadership development through volunteer involvement
Get PDFSubmission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2025-10-19 without embargo termsThe student, Gregory French, accepted the attached license on 2025-04-22 at 16:01.The student, Gregory French, submitted this Dissertation for approval on 2025-04-22 at 16:25.This Dissertation was approved for publication on 2025-04-23 at 09:08.DSpace SAF Submission Ingestion Package generated from Vireo submission #21897 on 2025-10-19 at 18:18:39This study aims to better understand the intricate landscape of student leadership development and motivation to lead within volunteer contexts. By examining diverse motivations and evaluating the way motivations can be categorized, this research utilized Chan and Drasgow’s Motivation to Lead theory (2001), Stewart’s Model of Situational Determinants (1967; 1976; 2002), and Astin’s Student Development Theory (1984). The purpose is to discover influences motivating student leadership development in volunteer contexts and reflective aspects of how leadership development is understood within student development. This study utilized a qualitative interpretive descriptive approach to comprehensively explore individual differences in student leadership motivation and address gaps in situational leadership understanding by emphasizing contextual impact on behavior (Stewart, 1967, 2002; Dugan, 2017). With a narrow focus on leadership development perceptions among students in volunteer settings, this research makes a unique contribution to the broader understanding of effective leadership education and theories on leadership motivation. With these goals in mind, the qualitative study addressed the following questions: • RQ1: What are motivators that influence students’ decisions to pursue and fulfill leadership within volunteer organizations? • RQ2: How do situational determinants influence the relationship between students’ motivation to lead and their development as leaders in a volunteer context? • RQ3: How are students’ experiences and self-perceptions understood through their motivation to lead and leadership behavior in volunteer contexts
Contemporary Egyptian art music for the viola through the ethnographic biographies and compositions of Yusif Gris, Gamal ‘Abd al-Rahim, ‘Atiyya Sharara, and Sherif Mohi al-Din for Western programs
Get PDFSubmission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2025-10-19 without embargo termsThe student, Christina Ebersohl-Van Scyoc, accepted the attached license on 2025-04-23 at 12:47.The student, Christina Ebersohl-Van Scyoc, submitted this Dissertation for approval on 2025-04-23 at 12:55.This Dissertation was approved for publication on 2025-04-25 at 13:32.DSpace SAF Submission Ingestion Package generated from Vireo submission #21918 on 2025-10-19 at 18:18:49For the purpose of this dissertation, contemporary Egyptian art music refers to compositions for soloists and ensembles that prominently feature Western instruments such as percussion, brass, and strings while also integrating Egyptian instrumentation (including the qanun, nāy, etc.) as well as folk-inspired elements. This category is distinct from Egyptian folk and popular musics which follow different stylistic and structural conventions. Throughout the twentieth and twenty-first centuries, four generations of Egyptian composers have crafted a narrative of musical innovation in which the past and present converge, and where the melodies of their homeland resonate within the frameworks of so-called Western art music. This journey was not just a transcultural merging of styles per se, but a critical and ongoing reclamation and redefinition of national identity and musical heritage. Contemporary Egyptian art music is largely misunderstood and suffers from a significant lack of engagement by non-Arab scholars and musicians alike. This gap in interaction has arguably led to a regional isolation whereby the contemporary Egyptian art music community has and continues to be precluded from deserved global reception. This is due in large part to an absence of biographical writings on Egyptian musicians and composers in languages other than Arabic, as well as the wider inaccessibility of their music in the form of scores and recordings. This dissertation addresses this lacuna by linking four “ethnographic biographies” that connect the first-, second-, and third-generation Egyptian composers Yūsif Grīs (يوسف جريس),1899–1961, Gamāl ‘Abd al-Rahīm(جمال عبد الرحيم) , 1924–1988, ‘Aṭiyya Sharāra(عطية شرارة) , 1922–2014, and Sherīf Moḥī al-Dīn (شريف محي الدين), b. 1964, respectively. The disparate nature of their life stories is reflected in the methodology of this project which necessarily combines archival work with ethnography and oral history. In doing so, this dissertation bridges the past century of Egyptian art music through the lens of these composers’ approaches to string composition, particularly for the viola, and with a focus on how contemporary Egyptian art music composers write idiomatically for the instrument as well as how we might rethink the legacy of these compositions for the viola today. The outcome of this research is to provide new historical and compositional contexts and resources for a wider community of musicians and to expand the viola’s established repertoire to better reflect its global forces at work
Recovering epistemic sight in a neoliberalized world: critical economic literacy for the promotion of critical global citizenship education
Get PDFSubmission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2025-10-19 without embargo termsThe student, Cat Ho, accepted the attached license on 2025-04-23 at 19:52.The student, Cat Ho, submitted this Dissertation for approval on 2025-04-23 at 20:07.This Dissertation was approved for publication on 2025-04-24 at 13:17.DSpace SAF Submission Ingestion Package generated from Vireo submission #21934 on 2025-10-19 at 18:18:56Global Citizenship Education (GCE), integral to Sustainable Development Goal (SDG) Target 4.7, is widely acknowledged as essential for addressing pressing global challenges and fostering sustainable development. Among the key approaches to GCE, Critical GCE stands out for its emphasis on critical thinking and systemic critique, equipping learners to challenge structural inequalities and unjust systems. However, the dominance of neoliberal ideologies in our world and in education has prioritized economic outcomes over transformative learning which significantly hinders the implementation of Critical GCE in schools. While factors such as insufficient training and resources have been identified as barriers (UNESCO, 2021), deeper issues like epistemic blindness—educators' lack of awareness of their own epistemological assumptions (Andreotti, 2016) — remain under explored. This study addresses this gap by investigating the role of Critical Economic Literacy (CEL) in enabling educators to teach Critical GCE. Using an intentionalist orientational qualitative inquiry with a critical perspective, the research involved five secondary school teachers from an international school in Beijing in an eight-week CEL course. Data were collected over nine months through pre and post-course surveys, reflective journals, revised unit plans, semi-structured interviews, and Most Significant Change narratives, and analyzed using thematic analysis. The findings reveal that CEL facilitated teachers' recognition of their epistemic blindness, fostering critical reflexivity about their role in perpetuating neoliberal systems. This awareness led to a renewed sense of vocational responsibility and a stronger commitment to integrating Critical GCE into their teaching practices. The study highlights the transformative potential of CEL in empowering educators to become critical global citizens and to teach for Critical GCE. By proposing CEL as a pathway to advancing Critical GCE, this research contributes to efforts to challenge neoliberal hegemony in education and promote transformative and critical global citizenship education