Showing 251 - 260 of 317 Items
Activation of Hydrogen by Sterically Modulated Coinage Metal Catalysts via Mutual Quenching of Hard/Soft Acid/Base Mismatches
Date: 2024-01-01
Creator: Zach Leibowitz
Access: Open access
- To mitigate the devastating environmental impacts of climate change in the coming decades, it is imperative that we replace the use of fossil fuels with renewable energy sources such as wind, solar, and hydroelectric. As these renewable energy sources are inherently intermittent, there exists a need for sustainable mechanisms to store renewable energy for later use. While the direct use of dihydrogen (H2) as a combustible fuel would allow for energy storage without the harmful release of carbon dioxide (CO2) upon combustion, the practicality of H2 as a synthetic fuel is limited by its low volumetric energy density. Combining sustainable H2 production (e.g. electrolysis using energy from renewable sources) with subsequent carbon fixation (e.g. the hydrogenation of CO2) represents a promising pathway to the sustainable production of high-density synthetic fuels. We hypothesize that such a process could be catalyzed by an IPr**-supported catalyst containing a hard/soft acid/base (HSAB) mismatch, with a polarizable coinage metal acting as a soft acid. As such, the aim of our project is the construction of a catalogue of IPr**-supported copper, silver, and gold catalysts that we anticipate will facilitate the heterolysis of dihydrogen and subsequent hydrogenation of CO2. In the present paper, we report the synthesis and characterization of an IPr**-silver complex which will serve as a precursor to many of our proposed HSAB mismatch catalysts and discuss next steps as we construct our catalogue of catalysts.
Democracy Promotion in U.S. Counterinsurgency: Tracing Post-War Security Sector Reconstruction in El Salvador and Iraq
Date: 2020-01-01
Creator: Emma Redington Lawry
Access: Open access
- Throughout the 21st century, certain facets of the democratic peace theory have informed American foreign policy, as policymakers credit democracy promotion with long-term stability and peace. In contrast, many political scientists have documented the often destabilizing and violent effects of democratization, particularly in underdeveloped states. How can we reconcile these tensions, and in what ways do they affect American foreign policy abroad? Under the lens of just war theory, or the doctrine of military ethics detailing the conditions under which it is morally acceptable to go to war, wage war and restore peace after war, this paper seeks to examine security sector reconstruction in post-counterinsurgency eras. In doing so, my analysis documents the effects of electoral processes on security and underscores the many difficulties of post-war rebuilding processes. In understanding these difficulties, I attempt to extract crucial lessons from the “best case” scenario of El Salvador and the “worst case” scenario of Iraq, both of which illuminate the fundamental tension between democratization and stability.
Solvent Effect on Excited State Proton Transfer Mechanism of 8-Amino-2-Naphthol
Date: 2021-01-01
Creator: Gabrielle Vandendries
Access: Open access
- Photoacids, compounds that undergo excited state proton transfer (ESPT), have been utilized in different solar energy and lithographic applications.1, 2 The addition of functional groups and solvent can both change the ESPT mechanism of photoacids. In this study, the effect of solvent on the ESPT mechanism was explored using a model diprotic photoacid, 8-amino-2-naphthol (8N2OH). The photochemistry of 8N2OH in water and common nonaqueous solvents, acetonitrile, tetrahydrofuran (THF), and methanol, were studied using UV/Vis absorption, steady-state emission, and time-correlated single photon counting (TCPSC) emission spectroscopy. The results were analyzed using the Kamlet-Taft parameters. It was found that the ESPT mechanism of the cation in water is different from the mechanism in acetonitrile and THF. In water the excited cation forms the zwitterion, i.e. the OH site undergoes ESPT, while in acetonitrile and THF, the excited cation forms the neutral species, i.e. the NH3+ site undergoes ESPT. No ESPT was observed for 8N2OH in methanol. The effect of solvent mixtures on photoacidity was also investigated using acetonitrile and water mixtures. The solvent effects were more subtle; the time-resolved emission measurements showed the greatest stabilization of the excited neutral 8N2OH species at 20/80% acetonitrile-water mixtures. Finally, the ability to extend the solvent studies to ionic liquids, 1-ethyl-3-methylimidazolium (Im) trifluromethanesulfonate (OTF), was demonstrated. The combined studies reveal that solvent plays a large role in determining the ESPT mechanism and stabilization of 8N2OH.
A Foray into the Camp: Human and Ecological Liberation in Contemporary Queer Conversion Therapy Literature
Date: 2021-01-01
Creator: Mitchel Jurasek
Access: Open access
- Through the analysis of two contemporary conversion therapy novels in North America, this project explores the intersections of biopolitics (specifically camp theory), queer theory, ecocriticism, and YA literature. Emily Danforth’s The Miseducation of Cameron Post and Nick White’s How to Survive a Summer are paired with scholars such as Gilles Deleuze, Felix Guattari, Joshua Whitehead, Greta Gaard, Hannah Arendt, Giorgio Agamben, Claudio Minca, Catriona Sandilands, Luce Irigaray, and Michael Marder to create a complex and intricate understanding of how ecologies impact queer youths’ experience in conversion therapy camps. The effect of such an intersectional and ecological understanding of queer becomings creates a foundation for further discovery and offers examples for current and future people to find mutual liberation with the ecologies we exist in.
Chambers of Reflection: Rousseau, Tocqueville, and Self-Government in the Digital Age
Date: 2020-01-01
Creator: John Sweeney
Access: Open access
- Jean-Jacques Rousseau and Alexis de Tocqueville each warn that the dominant cultures of their days may hinder the project of self-government. Against the backdrop of advancing Enlightenment philosophy, Rousseau writes that as social visibility increases relative to intimate connection, the drive for recognition corrupts self-love. Following the American and French revolutions, Tocqueville explores the democratic erosion of social hierarchies. He writes that a rise in individualism may obscure “self-interest well-understood”—the perspective gained through collaboration with others, thoughtful reflection, and reverence for truths that lie beyond the dictates of cursory instincts. In this project, I apply these political theories to the Digital Age. I explain how the distinction between the physical world and the digital realm has actualized Rousseau’s depiction of double men, “always appearing to relate everything to others and never relating anything except to themselves alone.” In the era of social distancing, technological evolution threatens to induce regression in the sociability and reflective agency that promote our capacity for self-government. Accordingly, I argue that Rousseau’s theory of corrupted drive for recognition and Tocqueville’s theory of individualism inform a new danger to political freedom: digital tribalism.
Genetic Analysis of Cellular Adhesion in Arabidopsis thaliana
Date: 2021-01-01
Creator: Andrew Close Bolender
Access: Open access
- Plant cell adhesion is mediated by the extracellular matrix (ECM) or cell wall and plays an important role in plant morphogenesis and development. The amount, modification, and cleavage of pectin in the cell wall are major contributors to the adhesive properties of the ECM. To gain a more complete picture of plant cell adhesion processes, Arabidopsis thaliana seedlings were previously mutagenized and screened for hypocotyl adhesion defects. Genomic sequencing of one plant exhibiting an adhesion defect, isolate 242, showed that two mutations, one in cellulose synthase (CesA1) and another in a sugar transporter, are candidates for the causative mutation. This thesis reports that CesA1 is necessary for proper plant cell adhesion, while the sugar transporter encoded at At4g32390 is not. Dark grown seedlings homozygous for mutations in CesA1 stain in ruthenium red, indicating atypical adhesion, while those homozygous for null mutations in At4g32390 do not. Previous study of another adhesion mutant revealed ELMO1, a Golgi protein necessary for plant cell adhesion, and four additional homologs ELMO2-5 in the A. thaliana genome. Two of these homologs, ELMO2 and ELMO3, fused to GFP, colocalized with mCherry-MEM1 markers in the Golgi, but not mCherry-NLM12 ER markers, indicating that ELMO2 and ELMO3 are also Golgi proteins.
Word Embedding Driven Concept Detection in Philosophical Corpora
Date: 2020-01-01
Creator: Dylan Hayton-Ruffner
Access: Open access
- During the course of research, scholars often explore large textual databases for segments of text relevant to their conceptual analyses. This study proposes, develops and evaluates two algorithms for automated concept detection in theoretical corpora: ACS and WMD retrieval. Both novel algorithms are compared to key word retrieval, using a test set from the Digital Ricoeur corpus tagged by scholarly experts. WMD retrieval outperforms key word search on the concept detection task. Thus, WMD retrieval is a promising tool for concept detection and information retrieval systems focused on theoretical corpora.
"I Deny Your Authority to Try My Conscience:" Conscription and Conscientious Objectors In Britain During the Great War
Date: 2019-05-01
Creator: Albert William Wetter
Access: Open access
- During the Great War, the Military Service Act was introduced on January 27, 1916 and redefined British citizenship. Moreover, some men objected to the state’s military service mandate, adamant that compliance violated their conscience. This thesis investigates how the introduction of conscription reshaped British society, dismantled the “sacred principle” of volunteerism, and replaced it with conscription, resulting in political and popular debates, which altered the individual’s relationship with the state. British society transformed from a polity defined by the tenets of Liberalism and a free-will social contract to a society where citizenship was correlated to duty to the state. Building off Lois Bibbings’ research on conscientious objectors, this thesis nuances the analysis with the case studies of David Blelloch and Norman Gaudie. Framed by two theories—Benedict Anderson’s imagined community and Barbara Rosenwein’s emotional community—these case studies demonstrate how conscientious objectors exposed the incongruence of the British imagined and emotional community, and the redefinition of citizenship. By weaving these theories into the British Great War tapestry, this thesis contends that the British nation was imagined differently before the war than it was after the war because of the introduction of conscription. Drawing from parliamentary debate transcripts, newspaper articles, and archival material from the Imperial War Museum in London, and the Liddle Personal Collection at the University of Leeds, Blelloch’s and Gaudie’s respective case studies ultimately bait the question: “What does it mean to be British?”
GEM-PSO: Particle Swarm Optimization Guided by Enhanced Memory
Date: 2019-05-01
Creator: Kevin Fakai Chen
Access: Open access
- Particle Swarm Optimization (PSO) is a widely-used nature-inspired optimization technique in which a swarm of virtual particles work together with limited communication to find a global minimum or optimum. PSO has has been successfully applied to a wide variety of practical problems, such as optimization in engineering fields, hybridization with other nature-inspired algorithms, or even general optimization problems. However, PSO suffers from a phenomenon known as premature convergence, in which the algorithm's particles all converge on a local optimum instead of the global optimum, and cannot improve their solution any further. We seek to improve upon the standard Particle Swarm PSO algorithm by fixing this premature convergence behavior. We do so by storing and exploiting increased information in the form of past bests, which we deem enhanced memory. We introduce three types of modifications to each new algorithm (which we call a GEM-PSO: Particle Swarm Optimization, Guided by Enhanced Memory, because our modifications all deal with enhancing the memory of each particle). These are procedures for saving a found best, for removing a best from memory when a new one is to be added, and for selecting one (or more) bests to be used from those saved in memory. By using different combinations of these modifications, we can create many different variants of GEM-PSO that have a wide variety of behaviors and qualities. We analyze the performance of GEM-PSO, discuss the impact of PSO's parameters on the algorithms' performances, isolate different modifications in order to closely study their impact on the performance of any given GEM-PSO variant, and finally look at how multiple modifications perform. Finally, we draw conclusions about the efficacy and potential of GEM-PSO variants, and provide ideas for further exploration in this area of study. Many GEM-PSO variants are able to consistently outperform standard PSO on specific functions, and GEM-PSO variants can be shown to be promising, with both general and specific use cases.
Placemaking and Community-Building among Lesbian, Bisexual, and Queer (LBQ) Women and Non-Binary People during the Covid-19 Pandemic
Date: 2021-01-01
Creator: Gabby Unipan
Access: Open access
- This paper draws on data collected through in-depth interviews with multi-generational participants recruited from various online sites to explore the place-making strategies among lesbian, bisexual, and queer (LBQ) women and trans- and gender-non-conforming people (tgncp) during the Covid-19 pandemic. Historically denied public space, placemaking in immaterial space (i.e., digital spaces) has been essential to the production and maintenance of communities for LBQ women and tgncp. Because these populations rely on non-traditional placemaking strategies that are not always instantiated in material space, sociologists often overlook their efforts to create place for themselves. This paper corrects this omission by exploring how communities create place through the deployment of subcultural capital onto immaterial space. Introducing four main strategies of community placemaking, material-constant communities, material-transient communities, immaterial-constant communities, and immaterial-transient communities, this article expands sociological conceptions of space to accommodate the placemaking strategies of marginalized communities who might lack the economic and political resources to foster communities in material spaces. Beyond the investigation of lesbian-queer placemaking, this research contributes to the growing sociological literature exploring the multifaceted, fluid, contested, and ephemeral nature of place and placemaking in the context of increasing Internet use.