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Concept Of Operations Of Cislunar Mirror Satellites To Provide Augmented Lighting Of Dim Space-Based Objects, Alec E. Cook Mar 2023

Concept Of Operations Of Cislunar Mirror Satellites To Provide Augmented Lighting Of Dim Space-Based Objects, Alec E. Cook

Theses and Dissertations

The imaging and inspection of Resident Space Objects (RSOs) is an increasingly important mission as space-faring nations and commercial enterprises alike seek to develop means to repair and refuel spacecraft, as well as de-orbit RSOs to reduce orbital debris. Lighting conditions are not always advantageous for an imaging/inspection or repair/refuel spacecraft; therefore, the use of mirror spacecraft to reflect solar energy is proposed to illuminate dimly lit RSOs. The present research investigates the efficacy of space-based reflectors at examining spacecraft in the cislunar environment. Specific assessments include target spacecraft in geosynchronous Earth orbit and periodic orbits around selected Lagrange points, …

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Experimental And Computational Bearing Strength Of Fiber Metal Laminate With And Without Film Adhesive, Christopher L. Bellanova Jr. Mar 2023

Experimental And Computational Bearing Strength Of Fiber Metal Laminate With And Without Film Adhesive, Christopher L. Bellanova Jr.

Theses and Dissertations

This research characterized the performance of a fiber metal laminate composed of carbon fiber and stainless steel without film adhesive and compared it to a similar, previously tested, fiber metal laminate including film adhesive. Removal of the adhesive layers reduced the localized thickness, simplified manufacturing, and allowed for a 20% increase in foil thickness. Quasi-static testing was conducted in double shear, single shear protruding, and single shear countersunk configurations. The results were compared to adhesive hybrid and control samples. To study the affects of bolt tension, samples at low torque in double shear were also tested. Progressive failure samples revealed …

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Estimation Of Optimal Flight Trajectory In A Total Power Loss Scenario Using Proximal Policy Optimization, Eidahn Eliash Mar 2023

Estimation Of Optimal Flight Trajectory In A Total Power Loss Scenario Using Proximal Policy Optimization, Eidahn Eliash

Theses and Dissertations

Recent research has been conducted in using deep reinforcement learning algorithms to generate closed form optimal control laws for helicopters in power loss scenarios. The control laws could allow for design of various cockpit visual pilot aids if proven successful. Such pilot aids are predicted to reduce pilot workload during execution of an emergency powerless landing, and to overall increase the probability of landing safely in such an event. The proposed topic discusses the use of the PPO algorithm in order to find an optimal control policy for a helicopter in a total power loss emergency landing scenario. The task …

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Suitability Of Earth-Moon Triangular Lagrange Point Orbits For Space Situational Awareness, Eric P. Burkhart Mar 2023

Suitability Of Earth-Moon Triangular Lagrange Point Orbits For Space Situational Awareness, Eric P. Burkhart

Theses and Dissertations

The second space race is looming on the horizon, and the Moon is again at center stage. All major space fairing nations have plans for future Lunar exploration, but this time with plans to stay. NASA’s Artemis program plans to put humans back on the Moon in 2025 and establish a Lunar base on the South pole in the 2030s. Meanwhile, China has landed a rover on the far side of the moon with a communications relay satellite in a halo orbit around the L2 Lagrange point, and partnered with Russia to build a Lunar research station on the Lunar …

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Gaseous Fuel Combustion In A Small Turbojet, Katherine A. Ashton Mar 2023

Gaseous Fuel Combustion In A Small Turbojet, Katherine A. Ashton

Theses and Dissertations

This project set out to test the suitability of natural gas as an aviation fuel by comparing how a small turbojet performed when run on traditional jet fuel versus methane. A JetCat P400, originally designed for jet fuel, was modified to run on methane. The modifications made did not succeed at getting the engine to run at normal operating speed on methane, but did get the engine to run at normal operating speeds using ethylene and ethane. It was determined a fuel and air mixing problem was hindering the engine performance when run on methane Future studies improving the fuel …

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Overall Effectiveness Superposition Theory For A Film Cooled Leading Edge, Bailey W. Hopkins Mar 2023

Overall Effectiveness Superposition Theory For A Film Cooled Leading Edge, Bailey W. Hopkins

Theses and Dissertations

Film cooling experimentation traditionally reports on the cooling performance of specialty-crafted cooling holes at various angles and array patterns. This is repeated across a variety of model geometries in an effort to provide as much information to the turbine blade designer. While this extensive database of cooling performance is helpful, its true value is found in the designer’s ability to effectively superpose the results on top of each other. One technique for predicting the performance of multiple coolant sources is film cooling superposition theory. This analytical model was employed classically by characterizing the adiabatic effectiveness across a model’s surface; however, …

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Anisotropic Characterization Of Additively Manufactured Ti 6-4 Via Tension, Compression, And Three Point Bend Experimentation, James M. Gunderson Mar 2023

Anisotropic Characterization Of Additively Manufactured Ti 6-4 Via Tension, Compression, And Three Point Bend Experimentation, James M. Gunderson

Theses and Dissertations

Titanium's ability to fill existing material gaps because of its higher strength and higher melting temperature compared to other common materials used in aircraft structures requires a need to understand the behavior of the material. Titanium's properties and the development of additive manufacturing also open an opportunity for it to be used in aerospace systems of the future in applications where traditionally manufactured titanium cannot meet the desired system requirements. Compressive, tensile, and three point bend experimental data collected from this research under varying temperatures, print orientations, print layer build heights, and surface finishes were analyzed to determine favorable material …

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Performance Analysis And Recommended Improvements Of A Cubesat Resistojet, Alexander M. Petrocelli Mar 2023

Performance Analysis And Recommended Improvements Of A Cubesat Resistojet, Alexander M. Petrocelli

Theses and Dissertations

A small resistojet design was evaluated for its current performance and assessed for design and operational improvements. This resistojet is designed to operate on AFIT CubeSats with the intent of providing 100-200 mN of thrust at a specific impulse between 66-104 seconds. Using previously collected data and studies conducted on the design, analysis was performed to determine the current performance of this first-generation design. This provided a starting point for performance analysis over a variety of operational temperatures and pressures. This process was conducted for various heat exchanger path lengths of both the current design and two adapted path geometries. …

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Investigation Of Hypersonic Near-Wake Relaminarization Over A 7 Degree Half-Angle Cone, Jesse L. Roberts Mar 2023

Investigation Of Hypersonic Near-Wake Relaminarization Over A 7 Degree Half-Angle Cone, Jesse L. Roberts

Theses and Dissertations

To investigate the potential for relaminarization in the near-wake of a 7-degree half-angle cone, a series of hypersonic wake experiments were conducted in the Air Force Research Laboratory Mach 6.1 Ludwieg tube. Relaminarization is a spatial phenomenon that occurs when a turbulent flow reverts to a laminar-like state at a downstream location, where turbulent fluctuations negligibly contribute to average flow properties. Although relaminarization has been documented in subsonic and supersonic flows, the current body of knowledge related to the occurrence of, and mechanisms that drive, relaminarization at hypersonic speeds is sparse. Measurements were obtained across a range of freestream unit …

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Shock Induced Trailing Edge Separation Effect On F-16 Limit-Cycle Oscillation, Eric D. Stubblefield Mar 2023

Shock Induced Trailing Edge Separation Effect On F-16 Limit-Cycle Oscillation, Eric D. Stubblefield

Theses and Dissertations

No abstract provided.

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Mechanical Properties And Performance Of A Novel Nano-Engineered Unitized Composite With Quasi-Isotropic Layup, Brian Matthew Pudlo Mar 2023

Mechanical Properties And Performance Of A Novel Nano-Engineered Unitized Composite With Quasi-Isotropic Layup, Brian Matthew Pudlo

Theses and Dissertations

Carbon nanotubes (CNTs) exhibit outstanding mechanical, electrical, and thermal properties, but are a challenge to effectively implement into macroscopic composites for aerospace applications. This research investigates the mechanical properties and performance of a newly developed hybrid NanoStitch composite, alongside a control polymer matrix composite, at room temperature. Both composite material systems investigated in this work have quasi-isotropic layup. Monotonic tension-tofailure, tension-tension fatigue, and creep tests were performed to characterize the performance of the composites under cyclic and sustained loading. Experimental results obtained for the quasi-isotropic NanoStitch composite were compared to those obtained for the quasi-isotropic control composite. The properties and …

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Improving Accessibility And Efficiency Of Analytic Provenance Tools For Reverse Engineering, Caleb W. Richardson Mar 2023

Improving Accessibility And Efficiency Of Analytic Provenance Tools For Reverse Engineering, Caleb W. Richardson

Theses and Dissertations

Reverse engineering is a vital technique for identifying and mitigating cyber threats. Yet, despite its importance, reverse engineering is a time-consuming process. Provenance tools help to improve the workflow of reverse engineers by providing an accessible method of viewing their flow through a binary. The current state-of-theart provenance tool for reverse engineering software called SensorRE, leverages an external server, web browser, and a large array of javascript libraries. This thesis presents Provenance Ninja, a software reverse engineering tool developed in Python that runs directly within Binary Ninja. Provenance Ninja captures reverse engineers’ provenance data and provides an interactive graph within …

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Debris Survivability Study For Mega-Constellation Architectures, Joseph C. Canoy Mar 2023

Debris Survivability Study For Mega-Constellation Architectures, Joseph C. Canoy

Theses and Dissertations

The analysis for the overall theoretical debris survivabilty of mega-constellation architectures, with an emphasis on space-based ballistic missile defense constellation (SB-BMD), is explored via three extensive different Monte Carlo simulations: preliminary analysis of low Earth Orbit (LEO) mega-constellation survivabilty following a fragmentation event within the constellation, analysis of LEO mega-constellation survivability with a fragmentation event occurring on a satellite performing a maneuver to insert itself within the constellation, and the analysis of LEO mega-constellation survivabilty after a fragmentation event resulting from the destruction of a missile. The LEO mega-constellations represent the SB-BMD constellation. The first two analysis sections will include …

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Direct Collocation Methods For Comparison Of Aerothermodynamic Models Effect On Hypersonic Trajectory Optimization By The Process Of Continuation, Noor K. Khan Mar 2023

Direct Collocation Methods For Comparison Of Aerothermodynamic Models Effect On Hypersonic Trajectory Optimization By The Process Of Continuation, Noor K. Khan

Theses and Dissertations

An algorithm was created to optimize trajectories of hypersonic glide vehicles with selected cost functions by applying the process of continuation to direct orthogonal collocation methods. The trajectory was optimized to maximize the range of launch position given a fixed terminal location. The hypersonic glide vehicle system dynamics were modeled with three-dimensional, three degree of freedom equations of motion assuming no thrust and a non-rotating Earth with the control as bank angle. Three aerothermodynamic models were compared when input as path constraints to calculate the stagnation point heating rate at the nose as well as integrated for heat load. Use …

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Characterizing Jet Interaction Effects On A Cone In Mach 3.9 Flow, Titus J. Lee Mar 2023

Characterizing Jet Interaction Effects On A Cone In Mach 3.9 Flow, Titus J. Lee

Theses and Dissertations

Although jet interaction in the context of attitude control for aircraft and air weapons have been investigated for a variety of conditions and geometries, the knowledge base for their use with hypersonic vehicles is far more limited. The objective of the present investigation is to characterize the jet interaction effects in a Mach 3.9 freestream in the AFIT Small Supersonic Wind Tunnel using schlieren flow visualization and a 6-degree of freedom balance. A 7° aluminum cone was attached to the balance while air was injected through a stainless-steel tube, which was separately supported without any contact with the cone body …

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Optimal Gyroid Infill For Space Launch, Jose R. Lopez Cordell Mar 2023

Optimal Gyroid Infill For Space Launch, Jose R. Lopez Cordell

Theses and Dissertations

This research characterizes the optimal gyroid infill design for the 1st frequency response of composite sandwich panels. Structural performance may be improved by designing the gyroid infill within the sandwich panel to have a 1st mode resonance frequency above typical launch vehicle vibrations. Ensuring a component generates a natural frequency response above a designed threshold is mandatory for space launch systems to prevent damage. The gyroid, a Triply Periodic Minimal Surface (TPMS), has the potential to provide close to isotropic stiffness in the principal axes with a minimal amount of material, making it an attractive choice for this application. This …

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Critical Infrastructure System Resiliency Modeling Using Multi-Layer Network Optimization, Spencer R. Figge Mar 2023

Critical Infrastructure System Resiliency Modeling Using Multi-Layer Network Optimization, Spencer R. Figge

Theses and Dissertations

ccurately modeling the interdependent operation of critical infrastructure systems is an effective and efficient way of proactively evaluating system vulnerabilities and resiliency. Infrastructure systems are designed to transport essential commodities from where they are produced to where they are consumed and network flow-based models are one of the most effective ways to simulate and quantify infrastructure performance. The literature is populated with proposed models that must balance accuracy of interdependent operations, capability to include real-world considerations, and computational cost. This research proposes an alternative network-flow based model called the Critical Infrastructure System Resiliency Model (CISRM) that focuses on modeling a …

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Optimal Control Of Precision Airdrop Trajectories Using Direct Collocation And Analytical Methods, Edward J. Maxwell Mar 2023

Optimal Control Of Precision Airdrop Trajectories Using Direct Collocation And Analytical Methods, Edward J. Maxwell

Theses and Dissertations

The work herein investigates the preliminary designs of an optimal navigation controller for a scalable cylindrical airdrop system controlled with grid fins in planar motion. Precision airdrop capabilities are desired for a range of military and humanitarian missions. Fielded airdrop systems have not met desired performance objectives, particularly regarding accuracy. Direct collocation and analytical methods were utilized to solve the optimal control problem for the grid fin controlled precision airdrop system examined in this work. The optimal control problem was comprised of two phases: controlled descent and parachute descent. Minimum and maximum ranges for the system under varying wind fields …

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Detonation Confinement In A Second-Generation Radial Rotating Engine, John T. Ursino Mar 2023

Detonation Confinement In A Second-Generation Radial Rotating Engine, John T. Ursino

Theses and Dissertations

In recent years, Rotating Detonation Engines (RDEs) have been coupled with turbomachinery to harness the benefits of detonative combustion. A novel type of RDE, referred to as the disk or Radial RDE (RRDE), has been developed in pursuit of length and weight savings compared to a traditional annular flow RDE. This design includes a disk-shaped device within which reactants flow from the outer radius, detonate, and exit the inner radius. In this paper several modifications have been made to a previously tested RRDE to address issues that arose with the original design. The combustion chamber diameter has been increased to …

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Development Of Novel Turbomachinery Manufacturing Methods, Timothy P. Winkler Mar 2023

Development Of Novel Turbomachinery Manufacturing Methods, Timothy P. Winkler

Theses and Dissertations

Compact turbine engines are of increasing interest as a means of propulsion for small, lightweight, low cost, unmanned aerial systems. This study looks to leverage advancements in novel manufacturing technology to produce turbomachinery components while simultaneously reducing costs and manufacturing time. To determine the feasibility of drop-in replacements for stock components this study focused on several research areas. This included materials research on both polymer-reinforced and ceramic materials, specimen tensile testing to determine temperature-dependent material properties, finite element analysis of multiple candidate materials, design and fabrication of a spin test rig, and physical spin testing of manufactured components to predict …

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Investigating Heterologous Transgene Expression In N. Crassa, James Christopher Mierendorf Mar 2023

Investigating Heterologous Transgene Expression In N. Crassa, James Christopher Mierendorf

Theses and Dissertations

First adopted as a model organism by Shear and Dodge in 1927, the filamentous fungus Neurospora crassa is among the most well studied eukaryotic systems today, facilitating major discoveries in genetics, biochemistry, and molecular biology. The sequencing of the Neurospora genome was completed in 2003, which combined with the organism’s fast growth, simple culturing requirements, and haploid life cycle, make it a particularly attractive model system. Despite these advantages, Neurospora crassa’s research value is diminished by its recalcitrance to expressing ectopic sequences incorporated into its genome. As a result, molecular techniques requiring heterologous expression (such as CRISPR) are largely incompatible …

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What Black Students Need From White Teachers: A Qualitative Inquiry, Renee Sherie Andrews Mar 2023

What Black Students Need From White Teachers: A Qualitative Inquiry, Renee Sherie Andrews

Theses and Dissertations

Black high school students who attend majority-white schools are educated in environments that are contradictory to their cultural backgrounds. Because the teachers at these high schools tend to be mostly white, Black students in these environments t typically feel a lack of connection or that they do not belong. In this qualitative study, I explored the relationships between Black students and their white teachers. Data sources for this study included interviews of both Black students and their teachers. From the data, I found that Black high school students need the following from their teachers: (1) check in on them regularly; …

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Time-Phasing Rdt&E In Air Force Acquisitions, Trevor A. Bills Mar 2023

Time-Phasing Rdt&E In Air Force Acquisitions, Trevor A. Bills

Theses and Dissertations

Time-phasing describes the process of estimating expenditure profiles for multi-year RDT&E acquisition programs. The AFCAH states that one approach to producing a time-phased estimate is with the use of S-curve distributions. These S-curves are most typically modeled as Weibull, Rayleigh, or Beta distributions. Many prior studies have been completed to better understand which of the three distributions is best suited to time-phasing RDT&E programs, and what program characteristics significantly explain variance in the distributional parameters. Those prior studies utilized either contractor-supplied data or SARs, and typically found the Weibull to be the best performing distribution. This paper makes novel use …

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Fragility Of The Florida Panhandle's Electrical Transmission Grid To Hurricanes, Zachary D. Schumann Mar 2023

Fragility Of The Florida Panhandle's Electrical Transmission Grid To Hurricanes, Zachary D. Schumann

Theses and Dissertations

The increased frequency and intensity of extreme weather events from climate change necessitates understanding impacts on critical infrastructure, particularly electrical transmission grids. One of the foundational concepts of a grid’s resilience is its robustness to extreme weather events, such as hurricanes. Resilience of the electric grid to high wind speeds is predicated upon the location and physical characteristics of the system components. Previous modeling assessments of electric grid failure were done at the systems level with assumptions on location and type of specific components. To facilitate more explicit adaptation metrics, accurate component-level information is needed. In this study, we build …

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Developing And Assessing A Generalized Serious Game That Supports Customized Joint All-Domain Operations Related Learning Objectives, Jonathan D. Moore Mar 2023

Developing And Assessing A Generalized Serious Game That Supports Customized Joint All-Domain Operations Related Learning Objectives, Jonathan D. Moore

Theses and Dissertations

As the threat of near-peer adversaries has increased, the DoD has increased its emphasis on Joint All-Domain Operations (JADO). This emphasis on JADO highlights the need for hands-on training that can engage military members at all levels. The serious game Battlespace Next (BSN) was designed to teach high-level JADO concepts by modeling real-world military assets in the context of a strategic card game. To keep pace with the evolving landscape of warfare as well as fit the needs of a variety of Department of Defense (DoD) communities, this research introduces the Battlespace Next Education Framework (BSNEF). The BSNEF allows JADO …

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The Effects Of Introversion And Treatment Delivery Modality On Therapeutic Outcomes In A Community Mental Health Clinic, Maria Olga Consbruck Mar 2023

The Effects Of Introversion And Treatment Delivery Modality On Therapeutic Outcomes In A Community Mental Health Clinic, Maria Olga Consbruck

Theses and Dissertations

Objective: The present study examines the effectiveness of teletherapy services for individuals with varying levels of introversion. This study also investigates the comparability of teletherapy to in-person services provided by clinicians in training. Introduction: Virtual platforms, such as teletherapy, have exponentially increased in use by clinicians and community members due to the Covid 19 pandemic. The pandemic has illuminated surprising secondary benefits of teletherapy. Research has shown that teletherapy results in greater accessibility, feasibility, and acceptability of treatment. Teletherapy platforms can reach remote and rural communities, and better address financial and time barriers. Current research indicates that teletherapy services are …

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Predictors Of Probation Outcome And Recidivism Among Nonviolent Drug Offenders In Mandated Treatment, Kira Elisabeth Johnson Mar 2023

Predictors Of Probation Outcome And Recidivism Among Nonviolent Drug Offenders In Mandated Treatment, Kira Elisabeth Johnson

Theses and Dissertations

Since the early 1990’s, the criminal justice system has been attempting to address the growing numbers of drug crimes and incarcerations resulting from policy decisions meant to discourage drug use and trade. To address resulting overcrowding in the prison system, drug courts and state mandated drug programs were devised to supervise and treat offenders in the community. Many factors have been identified that affect recidivism and related outcome measures for those mandated to drug treatment programs and probation terms, including age, gender, race, duration of treatment, and dosage of treatment. The current study found that age, gender, treatment duration, and …

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U.S. Army Force Structure Optimization And Sufficiency Analysis, Francis P. Gargin Mar 2023

U.S. Army Force Structure Optimization And Sufficiency Analysis, Francis P. Gargin

Theses and Dissertations

The United States Army perpetually deploys rotational forces across the globe in support of the National Security Strategy. These forces meet a set of discrete mission demands over an extended time period before redeploying, modernizing, and preparing for the next deployment. The U.S. Army now utilizes the Regionally Aligned Readiness and Modernization Model to execute these cyclical stages for unit deployments. Specific emphasis is placed on aligning forces against a Geographic Combatant Command, which allows units to build readiness and lethality oriented towards the same series of threats, physical terrain, and civilian considerations. This research provides an Integer Programming model …

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Exploring Informal Mentoring Relationships Between Faculty And Undergraduate Students At A Midwest, Urban Institution, Thomas O'Ryan Menchhofer Feb 2023

Exploring Informal Mentoring Relationships Between Faculty And Undergraduate Students At A Midwest, Urban Institution, Thomas O'Ryan Menchhofer

Theses and Dissertations

Mentoring has long been a strategy leveraged to support college students' development and academic success. The majority of studies on mentoring have focused on formal mentoring programs that involve a structure and the support of a program administrator. Studies have focused on mentorship outcomes such as increased academic achievement, persistence and retention, and career support. However, research focused on informal mentoring and the process of initiating and developing a relationship remains limited. This study uses qualitative interview data from 6 faculty and undergraduate student mentoring dyads to understand how participants initiate and further develop informal mentoring relationships and the perceived …

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Critical Choices: An Attempt At Understanding What I'M Trying To Understand Through Drawing Through Drawing, Amy Yeager Feb 2023

Critical Choices: An Attempt At Understanding What I'M Trying To Understand Through Drawing Through Drawing, Amy Yeager

Theses and Dissertations

Saying “I’ve always drawn” feels stupid but it’s true. I have always drawn. I’ve spent my whole life using drawing to understand, and this thesis is no exception. Through the conventions of comic, I explore my current practice which concerns death, memorial, the ground, and an examination of the routines and rituals that lead me there. I believe in reverent observation and intentional, meticulous mark-making, driven by an understanding that what I am looking at cannot look back, at least in a human sense. Inspired by the obsessive and thorough artists Ellen Altfest, Josephine Halvorson, and Vija Celmins, I cultivate …

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