Showing 81 - 90 of 564 Items

Possessing Her: Embodying Identity in Exorcism Cinema Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2021-01-01
Creator: Alicia Echavarria
Access: Access restricted to the Bowdoin Community

Design, Fabrication, and Characterization of Unidirectional Interdigital Transducers Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2022-01-01
Creator: Shane Anthony Smolenski
Access: Access restricted to the Bowdoin Community
Sensitivity Analysis of Basins of Attraction for Nelder-Mead
Date: 2022-01-01
Creator: Sonia K. Shah
Access: Open access
- The Nelder-Mead optimization method is a numerical method used to find the minimum of an objective function in a multidimensional space. In this paper, we use this method to study functions - specifically functions with three-dimensional graphs - and create images of the basin of attraction of the function. Three different methods are used to create these images named the systematic point method, randomized centroid method, and systemized centroid method. This paper applies these methods to different functions. The first function has two minima with an equivalent function value. The second function has one global minimum and one local minimum. The last function studied has several minima of different function values. The systematic point method is a reliable method in particular scenarios but is extremely sensitive to changes in the initial simplex. The randomized centroid method was not found to be useful as the basin of attraction images are difficult to understand. This made it particularly troublesome to know when the method was working effectively and when it was not. The systemized centroid method appears to be the most precise and effective method at creating the basin of attraction in most cases. This method rarely fails to find a minimum and is particularly adept at finding global minima more effectively compared to local minima. It is important to remember that these conclusions are simply based off the results of the methods and functions studied and that more effective methods may exist.
From “This Revolution is Neither Communist nor Capitalist!” to “Long Live the Socialist Revolution:” The Deterioration of U.S.-Cuban Relations from 1958-1961
Date: 2023-01-01
Creator: Julia Lyne
Access: Open access
- This thesis studies the deterioration of U.S.-Cuban relations from 1958-1961. Mainly drawing from primary sources from the National Archives, it seeks to answer and understand how and why relations deteriorated so rapidly. It pushes against the common belief that U.S.-Cuban relations were doomed from the start, instead highlighting in Chapter One Fidel Castro’s rise to power (and Fulgencio Batista’s fall from power) and revealing that the U.S. government was not entirely against Castro’s seizure of power. Chapter Two explores Castro’s first year in power and the (futile) attempts made by both governments to keep relations alive. Finally, it closes with the destruction of official and unofficial relations, suggesting that President Eisenhower’s covert approval of the invasion of the Bay of Pigs marked the covert ending to political relations as well as rising economic and political tensions due to an incompatibility of demand and interest in the sugar and oil industries. Ultimately, this thesis suggests that it was not just a matter of communism that led to the destruction of U.S.-Cuban relations at the time; instead, it was because of compounding effects of other various other economic and political factors and incompatibilities, such as the sugar and oil industries, public and political slandering and attacks from both sides, and an increasing acceptance of the Soviet Union and its supporters. This analysis does not seek to argue against the influence of communism in its entirety; rather, it aims to highlight and nuance the contributing factors to this deterioration.
Properties of Slicing Conditions for Charged Black Holes
Date: 2023-01-01
Creator: Sean E. Li
Access: Open access
- We consider an earlier analysis by Baumgarte and de Oliveira (2022) of static Bona-Massó slices of stationary, nonrotating, uncharged black holes, represented by Schwarzschild spacetimes, and generalize that approach to Reissner-Nordström (RN) spacetimes, representing stationary, nonrotating black holes that carry a nonzero charge. This charge is parametrized by the charge-to-mass ratio λ ≡ Q/M, where M is the black-hole mass and the charge Q may represent electrical charge or act as a placeholder for extensions of general relativity. We use a height-function approach to construct time-independent, spherically symmetric slices that satisfy a so-called Bona-Massó slicing condition. We compute quantities such as critical points and profiles of geometric quantities for several different versions of the Bona-Massó slicing condition. In some cases we do this analytically, while in others we use numerical root-finding to solve quartic equations. We conclude that in the extremal limit as λ → 1, all slices that we consider approach a unique slice that is independent of the chosen Bona-Massó condition. We then study dynamical, i.e. time-dependent, Bona-Massó slices by analytically predicting the qualitative behavior of the central lapse, i.e. the lapse at the black-hole puncture, for a particular slice that Alcubierre (1997) proposed to mitigate gauge shocks. These shock-avoiding slices are a viable alternative to the very common so-called 1 + log slices but exhibit different behavior in dynamical simulations. We use a perturbation of the radial coordinate at the location of the puncture to recover approximately harmonic late-time oscillations of the central lapse that Baumgarte and Hilditch (2022) observed in numerical simulations.

The Regulatory Effect of High Dopamine on the Hyperpolarization-Activated Inward Current (Ih) and its Role in the Stability and Rhythmicity of Mammalian Locomotor Neural Networks Access to this record is restricted to members of the Bowdoin community. Log in here to view.
- Restriction End Date: 2025-06-01
Date: 2022-01-01
Creator: Abigail Raymond
Access: Access restricted to the Bowdoin Community
A Problem Best Put Off Until Tomorrow
Date: 2023-01-01
Creator: Evan Albers
Access: Open access
- Effective Altruism has led a recent renaissance for utilitarian theory. However, it seems that despite its surge in popularity, Effective Altruism is still vulnerable to many of the critiques that plague utilitarianism. The most significant amongst these is the utility monster. I use Longtermsim, a mode of thinking that has evolved from Effective Altruism and prioritizes the far-future over the present in decision-making processes, as an example of how the unborn millions of the future might constitute a utility monster as a corporate mass. I investigate three main avenues of resolving the utility monster objection to Effective Altruism: reconsidering the use of expected value, adopting temporal discounting, and adopting average utilitarianism. I demonstrate that at best there are significant problems with these responses, and at worst, they completely fail to resolve the utility monster objection. I then conclude that if situations do exist in which the costs to the present do not intuitively justify the benefits to the far future, we must reject utilitarianism altogether.

Finite Element Modeling of Piezoelectric Surface Wave Focusing Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2022-01-01
Creator: Kieran Enzian
Access: Access restricted to the Bowdoin Community

Development of a Schiff base Synthetic Platform for 8-phenyliminonaphthol Photoacids Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2023-01-01
Creator: Ibrahim G. Saleh
Access: Access restricted to the Bowdoin Community
Synthesis of N-Heterocyclic Carbene Complexes of Coinage Metals and Their Application in the Activation of Hydrogen
Date: 2024-01-01
Creator: Maryam Akramova
Access: Open access
- The main cause of the ongoing global climate crisis is the emission of greenhouse gases, and current climate reports emphasize the need to transition to low-emission renewable energy sources. Urgently needed are methods for storing renewable energy, such as synthetic fuels like hydrogen (H2) gas; however, a challenge to the widespread implementation of hydrogen fuel is its low volumetric energy density. This thesis describes an effort to synthesize a catalyst that takes advantage of hard-soft acid-base (HSAB) mismatches to activate H2 and facilitate its reaction with CO2 to form hydrocarbon fuels, thereby providing a sustainable means of storing renewable energy in high-density carbon-neutral fuels. The catalyst design features an exceptionally bulky N-heterocyclic carbene (NHC) ligand known as IPr** (3-Bis[2,6-bis[bis(4-tert-butylphenyl)methyl]-4-methylphenyl]-1H-imidazol-3-ium chloride), a coinage metal acting as a soft acid, and a hard base such as an alkoxide ion. Herein is reported a modified synthetic route of IPr**, along with its metalation with silver, and preliminary results of the addition of an alkoxide base. The ligand and its complex with silver are structurally characterized by nuclear magnetic resonance (NMR) spectroscopy. Further work is needed to complete the characterization of IPr**-supported HSAB mismatch complexes and investigate their potential to activate H2.