Digital Commons Network^™

Advanced Oxidation Of Methyl Tert Butyl Ether With Ultraviolet Light Emitting Diodes, Aaron R. Neal

Theses and Dissertations

Methyl Tert-Butyl Ether (MTBE) is a volatile, soluble, organic compound introduced to gasoline within the United States as a fuel oxygenator in 1979. MTBE is a common groundwater pollutant due to its high water solubility and resistance to bio-degradation; it commonly infiltrates groundwater sources via leaking underground storage tanks or fuel spills. This research employed ultraviolet light emitting diodes (UV-LEDs) and hydrogen peroxide (H₂O₂) induced advanced oxidation process (AOP) to treat MTBE contaminated water at the bench scale. Using four H₂O₂:MTBE molar peroxide ratios (100:1, 200:1, 400:1, 500:1), MTBE degradation was induced …

Signal-To-Image Method For Counterfeit Detection In Layered Security Paradigm, Jordan Williamson

Theses and Dissertations

National level attention, resources, and priority regarding critical infrastructure have increased in recent years. This has led to adversaries and defenders exchanging positions between fortification and exploitation. One area that continues to be vulnerable is supply chain attacks like counterfeit insertion. This work investigates the application of converting collected signals into images from devices that may be considered for these critical networks. There are several aspects regarding the conversion of signals into images - specifically Red, Green, Blue (RGB) images. The methodology proposed here is potentially ideal fit for an initial security layer by achieving comparable classification results as more …

Spectroscopic Characterization Of Trivalent Holmium In Liyf4 And Bay2F8 Crystals, Vivian R. Hedberg

Theses and Dissertations

Yttrium-fluoride crystals doped with trivalent holmium are promising laser gain media for mid-infrared laser systems. To accurately model laser systems, a complete optical characterization of the laser gain medium is required. The key modeling parameters were obtained by a spectroscopic investigation of Ho³⁺ in LiYF₄ and BaY₂F₈ crystal hosts. Several important mid-infrared laser transitions were characterized at nominal Ho³⁺ ion concentrations of 10-30 at.%. Polarized emission cross-sections were determined from the fluorescence spectra using the Füchtbauer-Ladenburg method. Polarized absorption cross-sections were obtained using the Integral Reciprocity method. The upper-state lifetimes were measured at room …

Single Particle Analysis Of Operation Roller Coaster Environmental Samples, Caleb J. Sapp

Theses and Dissertations

The release of plutonium and other actinides into the environment following a nuclear detonation or accident, poses a health risk to biological systems. The spread, or transportation of that plutonium and its daughter products through environmental and meteorological means increases the potential affect and inherent danger within the surrounding area. In the 1960’s, a study was conducted in a joint effort by the US and Great Britain to collect information regarding the spread of plutonium released into the environment through a sub-critical detonation. Soil samples from these tests were collected by the USAF in 2015, approximately 50 years after these …

Assessing The Relationship Between The Quasi-Biennial Oscillation And D-Region Electron Density, Natalie R. Wirth

Theses and Dissertations

High frequency (HF) communication is a vital aspect of military communication and is highly reliant upon ionospheric conditions. The variation in electron density within the lowest echelon of the ionosphere, the D-region, can significantly impact HF signals, making communication inconsistent and unreliable for these wavelengths. Despite the D-region’s important, research in this area mainly focuses on understanding the impact of space weather anomalies on the upper ionosphere, particularly its higher layers, with relatively little exploration of the D-region. This region, situated closest to the troposphere and stratosphere, has been definitively linked to solar weather events like solar flares and geomagnetic …

Hardware-In-The-Loop Autonomous Trajectory Generations For On-Orbit Rendezvous And Proximity Operations, Connor Slattery

Theses and Dissertations

Utilizing the C++ version of GPOPS within a robotic operating system to assess efficacy on flight-ready hardware is a vital interest of the space industry today. The findings in this paper show the ability of employing GPOPS in C++ on flight-ready hardware, leveraging optimal control as the main driver to creating a control pipleline to allow a robotic platform to generate and follow an optimized trajectory with minimal user input.

Forecasting Stock Prices Using Arima Models And Technical Analysis, Muath I. Almaiman

Theses and Dissertations

This thesis explores the integration of Autoregressive Integrated Moving Average (ARIMA) models and technical analysis to forecast stock prices, with a focus on Coca-Cola's (KO) and Netflix’s (NFLX) stocks. It examines the effectiveness of combining ARIMA models, known for their predictive accuracy in time-series analysis, with technical indicators, particularly moving averages. The study evaluates whether this integrated approach can enhance the predictive capability of stocks prices beyond traditional methods. The predictive capability is evaluated using error metrics from the ARIMA models, as well as by assessing the return earned using simple rules based on the technical indicators. Utilizing data spanning …

Housing Preferences And Vertical Expansion Potential In Riyadh City, Nasser R. Alrashed

Theses and Dissertations

This research investigates the demand for apartment living in Riyadh's northern area and assesses its implications for vertical urban development, aligning with Saudi Arabia's Vision 2030. Employing a quantitative methodology, a structured survey was distributed to a diverse cross-section of Riyadh's population, focusing on housing preferences and perceptions of vertical living. Key findings indicate a significant demand for apartments, primarily from young to middle-aged, smaller households in low to middle-income brackets. Notably, a substantial portion of respondents showed a preference for high-rise living, suggesting a readiness for vertical expansion to manage the city's growing population. The study concludes that Riyadh's …

Trajectory Optimization Via Direct Collocation Methods Of Boost-Glide Vehicle With Newtonian Aerodynamic Model, Andrew Bonavita

Theses and Dissertations

In this work, a Newtonian aerodynamic model was developed for an elliptic cone glide geometry at a variety of angles of attack, and a functional relationship between an input angle of attack and the vehicle lift and drag coefficients was developed. This model was used in a direct orthogonal collocation framework to simulate a series of boost-glide trajectories, with objectives of minimum distance to target, minimum time to target, and maximum velocity to target. The optimal control problem was then expanded into a reachability study, considering a wide range of additional scenarios, along with studies on the vehicle range capabilities. …

Rapid Passive Safety Determination Using Backward Reachability For Spacecraft Rendezvous And Proximity Operations, Kealy A. Murphy

Theses and Dissertations

As the prevalence of autonomous space systems rise, there is an urgent demand for robust and precise safety analysis. The future of RPO necessitates coordination of satellites in a dynamic and congested space environment while avoiding collisions. Passive safety in RPO refers to the implementation of strategies that minimize the collision risk in the event of orbital or control deviations. This multifaceted problem includes maintaining KOZ, utilizing predictive modeling to anticipate collision scenarios, and designing spacecraft with robust GNC systems allowing for timely course corrections. The current literature’s focus has been on the separation distance between spacecraft as a primary …

Optimal Trajectory Solutions For Unmanned Pursuer/Evader Offensive Counterair Including Engagement Zone, Alexander Hansen

Theses and Dissertations

This work considers a two-actor scenario of a faster, unmanned pursuer with an engagement zone (EZ) and a non-maneuvering mobile evader. The pursuer aims to capture an evader with a circular EZ. The EZ is dynamic and shifts as a function of the evader’s velocity vector. As the evader’s strategy changes, the EZ relative to the pursuer adjusts based on relative heading and speed of the two agents. Using nonlinear optimal control techniques, the optimal trajectory and minimum time to engage the evader are determined for various pursuer initial headings and positions through MATLAB simulation. The results build a control …

Influence Of Environmental Barrier Coatings On The Overall Effectiveness Of A Film Cooled Ceramic Matrix Composite Plate, Shane P. Lindsay

Theses and Dissertations

Silicon carbide ceramic matrix composites, a promising new potential upgrade over the conventional metals currently used for jet engine turbine blades, have a propensity to oxidize in a combustion environment. Engine manufacturers often apply environmental barrier coatings to prevent the composites from oxidizing. What is unclear, however, is how environmental barrier coatings effect underlying composite temperatures. This research examined the coatings’ effects by first characterizing the influence of environmental barrier coatings on the underlying temperature of a protected ceramic, then evaluating the significance of lateral conduction for cooling a coated ceramic, and finally comparing cooling results for coated and uncoated …

Positioning, Navigation, And Timing (Pnt) Study For Select Multibody Environments, Kaitlin R. Roberts

Theses and Dissertations

In the renewed 21st-century race to the Moon, the demand for heightened mission capabilities in the cislunar region, lunar surface, and beyond is imperative. With an escalating number and complexity of lunar missions, persistent positioning, navigation, and timing (PNT) capabilities are becoming paramount. This thesis presents innovative lunar PNT architectures designed to provide continuous coverage of the lunar South Pole, near-continuous coverage of the entire lunar surface, and coverage of the Earth-Moon Corridor. As space faring countries advance from lunar exploration to Mars, similar assets are essential for astronaut exploration in this extraterrestrial environment. Additionally, this thesis introduces and meticulously …

Preliminary Assessment Of Cislunar Disposal Orbits, Ryan M. Sargent

Theses and Dissertations

This thesis investigates the disposal of end-of-life spacecraft from key orbits with a focus on minimizing delta-v expenditure and preventing debris propagation. Simulated Lyapunov and halo orbits around the L2 Lagrange point are analyzed for disposal feasibility. Both impulsive and continuous thrust methods are explored to achieve disposal trajectories. Continuous thrust will be modeled after a Hall thruster utilizing electric propulsion. Leveraging the Circular Restricted Three Body Problem framework, low delta-v cost trajectories are computed, with a multi-level correction algorithm optimizing total delta-v via heteroclinic connections. The study assesses various delta-v amounts for Earth-Moon system escape and evaluates the potential …

Origami Application And Attitude Control Investigation Of Space-Based Mirror System, David J. Garcia

Theses and Dissertations

Imaging and inspecting Resident Space Objects (RSO) have gained increasing importance in Space Situational Awareness (SSA) missions. These missions are driven by the necessity to perform satellite repairs, refueling, de-orbiting, and orbital debris reduction. However, the challenging lighting conditions in space often hinder these tasks. To overcome this challenge, a novel concept has been proposed—deploying mirrors from servicer satellites. These mirrors would harness solar energy to illuminate dimly-lit RSOs, enabling imaging, inspection, repair, and refueling operations. In this context, servicer satellites play a pivotal role in controlling the reflected light beam and precisely positioning themselves to illuminate RSOs effectively. Notably, …

Exploratory Analysis Of Cislunar Disposal Options For Select L1 And L2 Orbit Families, Rene Velazquez

Theses and Dissertations

The purpose of this research is to characterize the disposal options available for the planar and out of plane orbit families near the Moon. These options are meant to provide the impending Space Race around the cislunar regime a method to mitigate debris in the future. The disposal options are built upon a Sphere of Influence (SOI) reachability concept from a Circular Restricted Three-Body Problem (CR3BP). The SOI reachability will be based on the maneuver applied on a closed orbit in the velocity direction of the rotating frame. The post-maneuver trajectories will be propagated for 180 days and transformed into …

Small Unmanned Aircraft System Detection And Tracking With Audio, Computer Vision, And Deep Learning Techniques, Anthony C. Brunson

Theses and Dissertations

sUAS present significant risks to local and federal agencies when under the control of negligent, reckless, or criminal operators. In the face of an escalating presence of sUAS in shared airspace with traditional aircraft, and their deployment in protected airspace as potential weapons, safeguarding personnel, facilities, and assets becomes paramount. This research seeks to address this emerging threat by investigating the efficacy of integrating low-cost distributed sensors and Machine learning (ML) models to enhance battlespace awareness and complement existing sensing platforms for real-time sUAS detection, classification, and localization. The thesis introduces the conceptualization and development of a Drone Detection Command …

Performance Of Humans And Agents In A Systems Modeling Language V2 Task: A User-Centered Evaluation Approach, Allen W. Dukes

Theses and Dissertations

The Department of Defense is adopting Digital Engineering practices for its workforce. Simultaneously, the larger Systems Engineering community strives to modernize and define those Digital Engineering practices. These efforts to move from traditionally document-based approaches to pure digital implementations will require enhanced capabilities to manage and digitally track the lifecycle of a program or product. However, this growth must address tool design through an iterative process focusing on usability for many user types. Many tools and technologies exist but often lack an assessment of usability when engineers design tools for other engineers. Including usability when developing solutions for Digital Engineering …

Evasion Strategies For Space Engagements With Unknown Pursuer Objectives, Stephanie L. Halsey

Theses and Dissertations

Realistic simulations provide a tool for operators to understand space tactics and also serve to inform decisions on the requirements of current spacecraft technologies. This research uses simulation to gain a better understanding of one-on-one orbital conflicts through orbital differential games and linear quadratic games. The results of this research find that a simple strategy for an evading spacecraft to successfully evade a more-capable pursuing satellite for a variety of potential goals is to thrust perpendicular to the direction of the pursuer. Specific estimation requirements to accurately determine the objective of the pursuer and successfully evade in a realistic scenario …

Cost Estimating Relationships For Avionics Recurring Production Box Costs, Carla J. Cisneros

Theses and Dissertations

This research investigates a dataset of 286 Department of Defense (DoD) avionics boxes, employing regression methods to establish seven cost estimation relationships (CERs) for predicting avionics recurring production box costs. Not confined to T100 costs, three baseline models use Ordinary Least Squares (OLS) T100 cost, explaining 83%, 86%, and 83% of dataset variation. Additionally, four robust models depict mean and median, T100 OLS, and T100 non-linear learning curves, explaining 67%, 65%, 97%, and 87% of the variation. These models strike a balance between simple baseline and overly complex computational models. Identified cost drivers include weight, year of first flight, volume, …

Advanced Oxidation Of Tert-Butanol With Ultraviolet Light Emitting Diodes And Hydrogen Peroxide, Lauren R. Mainolfi

Theses and Dissertations

Tert-butanol (TBA), a versatile chemical widely used in industrial processes, poses exposure risks through inhalation, ingestion, and skin contact. Environmental contamination, often from industrial activities, emphasizes the importance of robust waste management and monitoring to protect water supplies from potential TBA migration and ensure drinking water safety. This study employed hydrogen peroxide (H2O2): TBA molar ratios of 100, 200, 400, and 500:1 in a Continuous Flow Stirred-Tank Reactor (CSTR) with UV-LED as the TBA degradation mechanism in an Advanced Oxidation Process (AOP). The UV-LEDs and H2O2 were synergistically employed to generate hydroxyl radicals in an advanced oxidation process. Gas chromatography–mass …

Sensor-Based Vehicle Classification Using Machine Learning, Luke Mcfadden

Theses and Dissertations

This research investigates the classification of vehicles into heavy and light categories using acoustic, seismic, and magnetic sensor data. The effectiveness of using frequency domain data and classical machine learning techniques, is compared with the effectiveness of using time-series data and neural networks. The primary aim in doing so was to understand if modern neural network architectures could effectively remove the need for more traditional frequency based signals processing. A significant deliverable of this thesis was the feature importance determined for each of the three phenomenological types found within the data (acoustic, seismic, and magnetic). By analyzing the importance of …

Development Of Salinomycin Derivatives As Potential Anticancer Agents, Viren Soni

Theses and Dissertations

Salinomycin is a poly-ionophore antibiotic that was originally isolated from Streptomyces albus by Miyazaki and colleagues from Kaken Chemicals Co., Ltd., Tokyo, Japan. Salinomycin exhibits antimicrobial activity against Gram-positive bacteria including Bacillus subtilis, Staphylococcus aureus, Micrococcus flavus, Sarcina lutea, Mycobacterium spp. Some filamentous fungi, Plasmodium falciparum, and Eimeria spp. as well as protozoan parasites responsible for the poultry disease coccidiosis. Hence, it is used in veterinary medicine. In 2009 Gupta et al demonstrated that salinomycin selectively killed human breast cancer stem cells (CSCs) with great efficacy, and the mechanism of action of this novel CSCs molecule was explored. To name …

Using An Anti-Deficit Framework To Explain The Academic Achievement Of Black Men In Higher Education: A Narrative Inquiry, Donald E. Reed

Theses and Dissertations

This dissertation explores the academic experiences of Black men who have completed their bachelor's degrees at predominantly white institutions (PWIs), utilizing an anti-deficit perspective. Despite the reality that only 36% of Black men achieve their undergraduate degrees within six years, this study shifts the narrative from focusing on obstacles to emphasizing success strategies, aiming to narrow the opportunity gap between Black men and their White peers. Through narrative inquiry and the Anti-Deficit Achievement Framework, this research not only showcases the resilience and determination of these individuals but also illuminates the varied strategies they employ to navigate their higher education journey …

Vulnerability Assessment Of Mangroves In Western Shore Of Red Sea, Nada Negm

Theses and Dissertations

Mangroves are vital to environmental sustainability and acts as a global warming control, although they endure severe vulnerability due to some human activities. Climate change and other extrinsic stresses are factors that play a vital role when assessing the vulnerability of mangroves in the Red Sea. The aim of this study is to assess the vulnerability of mangroves using field and RS data to apply a vulnerability index of mangroves at Hamatta and Safaga in Egypt. Mangrove Vulnerability Index covers includes hazard mangrove index, biological mangrove index and physical mangrove index.

Mangrove height has been measured using meter tape and …

Teachers’ Perceptions Of The Factors That Challenge And Advance Music Education In K-12 Schools: A Qualitative Study In Lebanon, Khaldoun Abou Dargham

Theses and Dissertations

Music education plays a crucial role in developing students on the individual level and societies on the communal level. Despite its benefits on the human brain, student learning, physical and mental health, and its contribution to culture and the creative economy, music education still faces challenges that prevent it from fulfilling its potential. Due to scant research on the factors that impact music education in Lebanon, this phenomenological study explored the perceptions of six K-12 music teachers in Mount Lebanon through in-depth interviews regarding the issue. Drawing upon the constructivist and humanistic learning theories, the research investigated how the Lebanese …

Exploring Purpose, Practices, And Impacts Of Non-Formal Education In Egypt, Mariam Hussien Sayed Abdelhamid

Theses and Dissertations

This research explores non-formal education in Egypt, analyzing its alignment or divergence with prevalent human capital and modernization discourses. Using a narrative approach, the study explores the practices of four organizations that offer non-formal education opportunities in greater Cairo: San3a Tech, Wataneya Society, Alwan wa Awtar, and AlAthar Lina. The study explores the narration of 9 educators and 10 learners from these organizations to understand from educators’ perspectives how they design their experiences and its relation to the culture and needs of the targeted audience. It also looks at what kind of impact do these experiences have on the learners. …

Investigation Of Fault Detection And Redundant Control Strategy For Model Predictive Control Of Distillation Column, Rajalakshmi R

Theses and Dissertations

Model Predictive Controller (MPC) is one of the industrial-ready control systems and an ideal choice for complex, slow-varying, and energy-intense Distillation Columns (DC). However, MPCs are subjected to failures and their performance degrades with faults and disturbances. Hence, there is a need for a redundant control strategy to ensure the continuous operation of MPC-controlled DC, which is investigated in this work.

A pilot-plant binary DC used to separate methanol and water is implemented with a computer-controlled system and is subjected to Pseudorandom Binary Excitation Signals (PRBS). The output response acquired is used to develop a MIMO (Multi-Input Multi- Output) state-space …

Design And Development Of Deep Eutectic Solvent Assisted Pressurized Liquid Extraction Of Nutraceuticals, Harish Babu B

Theses and Dissertations

Over recent decades, the usage of nutraceuticals has been exponentially increasing as alternates to pharmaceutical drugs. However, extraction of these therapeutically significant compounds from their corresponding sources requires the use of volatile organic solvents like hexane, ethanol and chloroform which increases the global warming potential. This problem has been overcome in recent decades by the use of supercritical carbon dioxide (SCO2) as the extraction solvent. Since SCO2 is non-polar in nature, the extraction of polar compounds with better efficiency is questionable.

On the other hand, modernization in solvent engineering has created generations of green solvents like ionic liquids (ILs), deep …

Improving Post-Secondary Credential Attainment: A Case Study Of Action Research In A Workforce Development Context, Peter James Selden

Theses and Dissertations

The purpose of this study was to understand what environmental, structural, group dynamic, programmatic, intermediate measure, or outcome measure factors influence the effectiveness of action research being used to improve postsecondary credential attainment for the Tulsa Talent Hub team. This case study focused on the perceptions of those team members that were involved in an action research or community-based participatory research project in Tulsa, Oklahoma, which was facilitated by a team of individuals from Impact Tulsa. The researcher examined how each member that was interviewed perceived overall impact and effectiveness of the action research process used. Through qualitative analysis, the …