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Electromagnetic Simulations of Exotic Phenomena in Engineered Materials:
Get PDFThesis advisor: Krzysztof Kempa“Simulations are like an experiment but on a computer.” – K. Kempa. Powerful ideas can be explored in immense detail and unmatched flexibility through computational resources. Combined with the beauty of electromagnetics, worlds of situations and problems can be uncovered. Of the many interesting phenomena available to study, a relatively recent explosion of engineered plasmonic materials has benefitted greatly from numerical breakthroughs in simulating Maxwell’s equations. Using these tools on novel metamaterial systems, composite materials with precisely designed structural features, the analysis and optimization probes the unique capabilities they have interacting with light. Example phenomena from this work includes fundamental principle breaking, extraordinary optical transmission, negative refraction, and superconductivity enhancement. The systems that harbor such outstanding feats fall into the umbrella term of metamaterials, each with distinct geometry and contrasting electrical properties that allow for an engineered control of the effective structural dielectric function. As the response to electromagnetic radiation, manipulating the dielectric function is key to creating and discovering the effects that control light, without changing any chemistry. This work scales pedagogically through the different types of metamaterials, beginning first with 2D planar checkerboard structures with highly non-linear percolation. In combination with spoofed plasmonics, the longstanding symmetry of the Babinet principle is challenged. Layers of checkerboards are then stacked and translated to create subwavelength gaps for which plasmonic coupling between layers aids in optical transmission. In fact, there is similar physics controlling other layered quasi-complementary structures shown by comparison to experimental transmittance data. A further stage introduces photonic crystals constructed out of 3D periodic lattice of nanoparticles. Photonic band structure calculations for properly designed systems suggest the possibility of bandwidths of the IR spectrum where the crystal has a negative refractive index. Such a material property allows for the invention of lenses that beat the diffraction limit, applicable to subwavelength imaging. Lastly, non-local extensions to plasmonics are theoretically worked into expressions for superconductivity, creating a resonant anti-shielding effect, in composite topological crystal/superconductor layered arrangements. Applying this to known topics, like Bi2Se3 and MgB2, shows significant boost to electron pairing and thus rises in superconducting critical temperature. Central to all the systems and effects explored are the modifications made to the dielectric function of each effective medium. Supported by electromagnetic simulations and theoretical efforts, the listed engineered materials transform the dielectric environment purposefully to originate the mentioned exotic optical phenomena.Thesis (PhD) — Boston College, 2023.Submitted to: Boston College. Graduate School of Arts and Sciences.Discipline: Physics
Border, Exclusion, and Embrace: Toward a Non-Exclusionary Conception of the Border
Get PDFThesis advisor: Kristin E. HeyerThesis advisor: Orfilio Ernesto ValienteMigration is one of the most salient characteristics of our time. It does not constitute a new phenomenon. Mobility is a fundamental dimension of human activity. People have always migrated all over the world. But today, more people are migrating due to the global interconnectedness of the world. Although people leave their homes for multiple reasons, there is agreement on the fact that the search for a better life is the primary cause. Migration is a complex phenomenon that affects not only people who move but also receiving communities. This complexity is translated into the never-ending debates over human rights, national security, and sovereignty. These ongoing discussions prove how border and migration are intertwined. Today it becomes impossible to address the question of migration without considering the relevance of international borders. In a time characterized by numerous flows of people, borders can be perceived differently. While the receiving countries see them as "institutions" for controlling the profile of entrants into their territories, migrants consider them as barriers prevening them from reaching a better quality of life, which is intrinsically tied to human dignity and rights. This shows that borders can have harmful impacts on people's lives. Hence, the question: What is the moral relevance of a border? Should the border be closed when dire situations threaten people's lives? This thesis attempts to address these questions. Its primary purpose is to propose a non-exclusionary understanding of the border that takes human dignity and rights into account. Its claim is that, from an ethical perspective, the border must not be seen as a marker of separation purely and simply but also as a place that connects people. The thesis is organized into three chapters. The first chapter tries to present different perspectives on the border. It highlights the border's moral relevance in terms of nation-states' sovereignty. It also stresses the inhuman consequences of the border in our epoch, marked by globalization and migration. The second chapter brings to the fore some ethical categories, such as the principle of humanity, imago Dei, compassion, solidarity, and hospitality, for addressing the issue of migration. It will present these categories as the criteria for a non-exclusionary definition of the border. It considers the relationship between Christian cosmopolitanism and national boundaries. Calling on Miroslav Volf's distinction between exclusion and embrace, it will propose a non-exclusionary understanding of the border and make a plea for more porous borders that give the possibility for people to embrace others. The last chapter of the paper will argue that this non-exclusionary conception of the border must influence the American immigration policy toward Haitian migrants. Exploring TPS and Title 42, it will highlight the double (positiive and negative) impact of U.S. immigration policy on Haitian rights. This chapter will argue that the United States has a moral responsibility toward Haitian migrants.Thesis (STL) — Boston College, 2023.Submitted to: Boston College. School of Theology and Ministry.Discipline: Sacred Theology
Ambrose's Teaching and Exemplars on the Virtues of Prudence and Fortitude and their Relevance to Contempoary Christians in Nigeria
Get PDFThesis advisor: Brian DunkleThesis advisor: Catherine M. MooneyEvery generation encounters moral problems. Thus, designing an ethical standard or a moral guide for any generation has been a major concern for great minds who believe in a genuine pursuit of happiness through virtuous life. Ancient philosophers like Socrates, Plato, Aristotle, and the Stoics debated on this in their time by acknowledging essential virtues such as wisdom, courage, justice, and temperance as moral principles. Marcus Aurelius Cicero followed the moral principles of these ancient Greek philosophers and, to encourage young Romans aspiring for leadership positions, wrote a book titled De Officiis, a handbook on duty and responsibility. Ambrose of Milan, a statesman turned churchman, who also studied the pagan virtues of these Greek philosopher and the work of Cicero, wrote De Officiis Ministrorum, a handbook on duty for clergy, religious, and Christians of his diocese. Ambrose adopted and adapted the pagan virtues into Christian virtues. The virtues of prudence and courage are critical virtues among the cardinal virtues that Ambrose analyzed in his work using biblical exemplars as models for Christians of his time. The current situation in Nigeria needs a reconsideration as corruption and other moral vices have occupied the central stage in Nigeria. Highlighting Ambrose's virtue theory and teaching on prudence and courage as part of daily catechesis and homily will be necessary for the development of moral consciousness and values among the Christians and non-Christians in Nigeria. This work traces the historical development of virtue theory from ancient times to the time of Ambrose. It uses historical analysis to bring forward the Christian virtues taught by Ambrose and their exemplars, and argues for emulation of these tremendous biblical exemplars and suggests modern and local exemplars from the Nigerian perspective and Africa at large.Thesis (STL) — Boston College, 2023.Submitted to: Boston College. School of Theology and Ministry.Discipline: Sacred Theology
The Intersection of Disability and Romance in Nineteenth-Century Literature
Get PDFThesis advisor: Maia McAleaveyMy thesis is about the intersection of disability and romance in nineteenth-century literature. I explore the gap in scholarly writing that often ignores how characters with disabilities fit into romantic relationships. I explain how, although people typically believe that characters with disabilities in Victorian literature do not participate in the romance plot, in actuality, it is because a character becomes disabled that allows them to flourish in a romantic dynamic. I coin the term "disability-romance plot" to describe the pattern where authors use disability as a mechanism to solve otherwise unsolvable conflicts within romantic pairings. In my essay, I outline the two types of disability-romance plots: the male disability-romance plot and the female disability-romance plot. Together, I look at how the disability-romance plot challenges stereotypes about people with disabilities and reveals gender norms in the nineteenth century.Thesis (BA) — Boston College, 2023.Submitted to: Boston College. College of Arts and Sciences.Discipline: Departmental Honors.Discipline: English
Essays on Two-Sided Matching Theory:
Get PDFThesis advisor: M. Utku ÜnverThesis advisor: Tayfun SönmezThis thesis is a collection of three essays in market design concerning designs of matching markets with aggregate constraints, affirmative action schemes, and investigating boundaries of simultaneous efficiency-stability relaxation for one-to-one matching mechanisms.In Chapter 1, I establish and propose a possible solution for a college housing crisis, a severe ongoing problem taking place in many countries. Every year many colleges provide housing for admitted students. However, there is no college admissions process that considers applicants’ housing needs, which often results in college housing shortages. In this chapter, I formally introduce housing quotas to the college admissions problem and solve it for centralized admissions with common dormitories. The proposed setting is inspired by college admissions where applicants apply directly to college departments, and colleges are endowed with common residence halls. Such setting has many real-life applications: hospital/residents matching in Japan (Kamada and Kojima, 2011, 2012, 2015), college admissions with scholarships in Hungary (Biró, 2012), etc.
A simple example shows that there may not be a stable allocation for the proposed setting. Therefore, I construct two mechanisms that always produce some weakened versions of a stable matching: a Take-House-from-Applicant-stable and incentive compatible cumulative offer mechanism that respects improvements, and a Not-Compromised-Request-from-One-Agent-stable (stronger version of stability) cutoff minimising mechanism. Finally, I propose an integer programming solution for detecting a blocking-undominated Not-Compromised-Request-from-One-Agent-stable matching. Building on these results, I argue that presented procedures could serve as a helpful tool for solving the college housing crisis.
In Chapter 2, I propose a number of solutions to resource allocation problems in an affirmative action agenda. Quotas are introduced as a way to promote members of minority groups. In addition, reserves may overlap: any candidate can belong to many minority groups, or, in other words, have more than one trait. Moreover, once selected, each candidate fills one reserve position for each of her traits, rather than just one position for one of her traits. This makes the entire decision process more transparent for applicants and allows them to potentially utilize all their traits. I extend the approach of Sönmez and Yenmez (2019) who proposed a paired-admissions choice correspondence that works under no more than two traits. In turn, I allow for any number of traits focusing on extracting the best possible agents, such that the chosen set is non-wasteful, the most diverse, and eliminates collective justified envy. Two new, lower- and upper-dominant choice rules and a class of sum-minimizing choice correspondences are introduced and
characterized.
In Chapter 3, I implement optimization techniques for detecting the efficient trade off between ex-post Pareto efficiency (for one side of a two-sided matching market) and ex-ante stability for small one-to-one matching markets. Neat example (Roth, 1982) proves that there is no matching mechanism that achieves both efficiency (for one side of the one-to-one matching market) and stability. As representative mechanisms I choose deferred-acceptance for stability, and top trading cycles for Pareto efficiency (both of them are strategy-proof for one side of the market). I compare performances of a randomized matching mechanism that simultaneously relaxes efficiency and stability, and a convex combination of two representative mechanisms. Results show that the constructed mechanism significantly improves efficiency and stability in comparison to mentioned convex combination of the benchmark mechanisms.Thesis (PhD) — Boston College, 2023.Submitted to: Boston College. Graduate School of Arts and Sciences.Discipline: Economics
Dehn surgery on knots in the Poincaré homology sphere:
Get PDFThesis advisor: Joshua E. GreeneWe develop and implement obstructions to realizing a 3-manifold all of whose prime summands are lens spaces as Dehn surgery on a knot K in the Poincaré homology sphere, and in the process, we determine the knot Floer homology groups of a knot with such a surgery. We show that such a surgery never results in a 3-manifold with more than three non-trivial summands, and that if the result of surgery has exactly three non-trivial summands, then K is isotopic to a regular Seifert fiber. We furthermore identify the only two knots with half-integer lens space surgeries, and thus complete the classification of knots in the Poincaré homology sphere with non-integer lens space surgeries. We lastly show that a lens space L(p, q) that is realized as integer surgery on a knot K is realized as integer surgery on a Tange knot when p ≥ 2g(K). In order to do so, we build on Greene’s work on changemaker lattices and develop the theory of E8-changemaker lattices.Thesis (PhD) — Boston College, 2023.Submitted to: Boston College. Graduate School of Arts and Sciences.Discipline: Mathematics
Exploring the structure, dynamics, and developmental trajectory of person models:
Get PDFThesis advisor: Liane YoungEffective social interaction requires reasoning about people as generative models. In our day-to-day experience, we come across a remarkable amount of social information, often in the form of other people’s behaviors. Observed behaviors are used to infer agents’ unobservable mental states and traits – the latent causes that drive their behavior. These inferences are stored in person models, which allow us to interpret patterns of observed behaviors across multiple instances and contexts by attributing a common cause to those behaviors, and also allow us to predict people’s future actions, so that we may navigate interactions smoothly and choose our social partners wisely. This dissertation pursued several open questions on flexible trait reasoning. In Paper 1, we found that the relative contributions of different traits to overall impressions may vary depending on what we know about a person. In Paper 2, we found increased neural activity in Theory of Mind regions following the violation of strong and positive prior impressions. In Paper 3, we found that 6-9-year-olds exhibit a negativity bias in impression updating, and older children are sensitive to the strength of behavioral evidence. Overall, we found evidence for flexible trait reasoning – both children and adults were sensitive to the strength and valence of available behavioral evidence, and to the overall inference context. These studies help shed light on how children and adults reason about person models and respond to new social information, and we suggest multiple avenues for further research in this arena.Thesis (PhD) — Boston College, 2023.Submitted to: Boston College. Graduate School of Arts and Sciences.Discipline: Psychology
Less Violent But No Less Visible: Criminalization and Community Murals in Brixton and Belfast, 1970-1989
No full textThesis advisor: Robert J. SavageThis dissertation compares that state-sponsored tactic of criminalization implemented against both the Black community of Brixton and the republican community of Belfast throughout the 1970s, arguing that both minority groups were criminalized in an attempt to end the ‘crisis of hegemony’ faced by the British government during the post-war decline of empire. While this process of criminalization was implemented via different legislative methods and with different ideologies, racial in Brixton and ethno-sectarian in Belfast, the government used these negative ideologies to create a specific narrative that supported the implementation of discriminatory policing policies against these marginalized groups. Both the Black and republican communities fought against this narrative of criminalization, instead highlighting parallel counter-narratives which contended that discriminatory governing and over-policing were negative symptoms of Britain’s enduring colonial legacy and a detriment to the minority populations of the United Kingdom. Tensions between the state-sponsored police and these marginalized communities exploded in 1981 with the uprising in Brixton and the hunger strike in Belfast. Members of both minority communities viewed these events as attempts to combat state discriminatory policies, but the British government viewed these violent events as proof of the criminality of these minority groups. Examining the creation and use of community murals in both Brixton and Belfast after 1981, this dissertation argues that murals became a less violent, but no less visible tool to combat the narrative of criminalization. As a type of artwork specifically designed for marginalized communities to challenge spatial and visual hegemony, community murals in these locations created large public canvases with which disenfranchised citizens could display their own visual representation – a representation to offset the negative imagery being portrayed by the British government and mainstream media. Minority groups in both Great Britain and Northern Ireland used these community artworks as subversive tools to positively display their marginalized cultures and their counter-narrative of discriminatory policies throughout the 1980s. While created via different artistic and collaborative methods, community murals in Brixton and Belfast became a tool used by both minority groups to combat the negative impacts of the shared criminalization that stemmed from a mutual colonial history.Thesis (PhD) — Boston College, 2023.Submitted to: Boston College. Graduate School of Arts and Sciences.Discipline: History
TheSecond-Generation Electrochemical Labeling of Hydroxyindoles with Chemoselectivity (eCLIC) for Site-Specific Protein Bioconjugation:
No full textThesis advisor: Abhishek ChatterjeeElectrochemistry has gained recognition for its precise control over reactions, mild conditions, and scalability in small molecule synthesis. However, its application in modifying complex biomolecules, including proteins, specifically through electrochemical site-specific labeling, is still relatively unexplored. The eCLIC, electrochemically-promoted coupling reaction, developed by the Chatterjee group enables the selective labeling of proteins using 5-HTP and aromatic amines under mild conditions. By incorporating 5-HTP through genetic code expansion, eCLIC allows for specific labeling of recombinant proteins. Although the technique offers advantages such as high conversion rates, broad substratescope, cost-effectiveness, and compatibility with existing labeling methods, its optimization for incorporating hydrophobic molecules is essential. Initial attempts to conjugate 5-HTP with hydrophobic molecules through eCLIC were challenging, but the incorporation of negatively charged functional groups, such as carboxylic acids, has shown to be promising in enhancing the reactivity of eCLIC reactions. This study investigates the use of tertiary aniline warheads with negatively charged functional groups in conjunction with hydrophobic molecules to improve reaction efficiency and stability. The results demonstrate that these functional groups facilitate more efficient carbon-carbon bond formation, leading to stable conjugation between the warhead and the target protein. The findings emphasize the potential of incorporating negatively charged functional groups in designing eCLIC reactions and their role in developing effective and versatile site-specific labeling strategies for complex biomolecules.Thesis (MS) — Boston College, 2023.Submitted to: Boston College. Graduate School of Arts and Sciences.Discipline: Chemistry
"It’s Not What You Know, It’s Who You Know”: How Social Capital Affects Perceptions of Self Efficacy Among Low Income Students
Get PDFThesis advisor: Gustavo MorelloGiven the endless times I have heard “It’s not what you know, it’s who you know”, the value of social networks became the forefront of this sociological study. Throughout this study I investigate the relationship between social capital and self efficacy. I interviewed ten undergraduate, low income students at medium sized school in the Northeast on their social connections throughout high school and college experience. These same respondents then took a General Self Efficacy scale to measure their perceived self efficacy. The study finds that those with higher measures of social capital also demonstrate higher perceived self efficacy. More importantly, social capital seemed to be more effective in providing resources and building self efficacy when there was a shared identity or experience between the student and the resource.Thesis (BA) — Boston College, 2023.Submitted to: Boston College. College of Arts and Sciences.Discipline: Departmental Honors.Discipline: Sociology