Digital Commons Network^™

The Study Of Biomass Based Polymers And Cyclic Polymers, Yishayah Bension

Theses and Dissertations

Plastics have become an integral part of everyday life, from household care to aerospace applications, polymers are involved in every industry. Most of these polymeric materials are derived from petroleum feedstocks which have deleterious effects on our environment. The production of petrochemicals has led to an increase in greenhouse gases and microplastic pollution which have accelerated climate change. My research focuses on utilizing existing biomasses to improve the plastic economy’s circularity. This work develops new materials from bio-based polymers such as lignin and soybean oil. Raw lignin suffers from inherently weak mechanical properties, poor solubility, processability, and molecular structure ambiguity. …

Damage Control Measures In Composites: Focus On Damage Tolerance Of Aerospace Structures, Kais Jribi

Doctoral Dissertations and Master's Theses

Barely Visible Impact Damage (BVID) in composite materials presents a stealthy yet significant risk to structural integrity, particularly challenging due to its elusive nature. The approach adopted here diverges from traditional methodologies, focusing on the novel application of Digital Image Correlation (DIC) to map surface area changes during in-situ Compression After Impact (CAI) tests. This technique allows for an in-depth analysis of planar strains along the x and y axes, shedding light on the material's behavior under stress.

A pivotal advancement lies in developing a method for precisely identifying when BVID-induced delamination recommences. By meticulously analyzing strain pattern deviations along …

Optimization Of Human Interactions In The College Campus Model Via Simio Integration, Benjamin E. Chaback

Doctoral Dissertations and Master's Theses

College campuses are a significant part of life in some cities. Many students each year attend university, pursuing additional knowledge from faculty members. Both staff and faculty members rely on these students to have successful jobs and to ensure the university functions. Yet recently, more and more students are attending, leading to overcrowding, lower admission rates, and difficulty getting into good programs. Previous work exists on qualitative student affairs and quantitative retention data, yet little on using simulations to model this problem. This work aimed to (a) Determine the ability to successfully model human interactions/people flow on a college campus, …

Factors Predicting Public’S Willingness To Support National Aeronautics And Space Administration’S Artemis Mission, Sean Crouse

Doctoral Dissertations and Master's Theses

NASA's Artemis program aspires to return astronauts to the moon and aims to land the first woman and person of color on the lunar surface. The endeavor symbolizes the next evolution in space exploration and serves as a testament to the human spirit of discovery. In the face of this significant undertaking, gauging public sentiment and understanding the factors driving public support becomes necessary. The current study aimed to address a critical gap in the literature by examining public support for NASA’s Artemis mission, which is essential for sustaining the program’s momentum and cultivating a culture of innovation and exploration. …

Ti Nano Powder Speckle Pattern Creation And Use In Dic Of Zno Modified Single Carbon Fibers, James Matthew Harris

Doctoral Dissertations and Master's Theses

As the use of composites continues to grow across aerospace, naval, automotive, construction, 3D printing, and other countless industries, so does the desire to continuously improve their mechanical properties. Improving the adherence of the fiber-matrix interface is one important step for amplifying the capabilities of composites. Work has been performed in modifying carbon fibers by growing zinc oxide (ZnO) nanorods in the fiber surface using a hydrothermal approach, increasing interfacial area and fiber-matrix friction. Macroscale evaluation has shown that the interfacial modification decreases the inter-ply movement and reduces the processing strains and residual stresses. To fully understand the mechanism taking …

Development Of On-The-Fly Quasi-Steady State Approximation For Chemical Kinetics In Cfd, Abhinav Balamurugan

Doctoral Dissertations and Master's Theses

This study analyzes the feasibility of On-The-Fly Quasi-Steady-State Approximation (OTF-QSSA) application for solving chemical kinetics within Computational Fluid Dynamics (CFD) simulations, aiming to reduce the computational demand of detailed mechanisms. An algorithm that dynamically identifies and designates Quasi-Steady-State (QSS) species at specific grid locations and instances during the simulation was developed. With this information, our method pseudo-delays the advancement of concentrations for these QSS species—effectively setting their rate of concentration change to zero for a set number iteration before updating using the detailed mechanism and thereby omitting the computationally intensive processes typically required for their calculation during those skipped iteration. …

Distributed Adaptive Control Methods For Uncertain Multiagent Systems With Coupled Dynamics, Islam Aly

Doctoral Dissertations and Master's Theses

For a multiagent system, a major challenge is achieving overall system stability and performance in the presence of not only uncertainties but also coupled dynamics. Another challenge for these systems is designing distributed adaptive controllers with user-assigned positions in this case and defining the convergence rate of the reference model for each agent using only local (i.e., agent-based) information. Discrete-time architectures have an advantage over their continuous counterparts as they can be directly executed on embedded hardware without the need for discretization. Yet, because of the difficulty of ensuring Lyapunov difference expressions, their designs, which are based on quadratic Lyapunov-based …

Numerical Study In Wind Energy Extraction From Controlled Limit-Cycle Oscillations In Modified Glauert Airfoil, Ethan L. Deweese

Doctoral Dissertations and Master's Theses

Typically, wind energy harvesting technology employs wind turbines. Towards the goal of meeting increasing energy needs with renewable energy sources a novel wind energy harvesting scheme is considered, utilizing a modified Glauert (MG) airfoil experiencing aeroelastic limit cycle oscillation (LCO) from which energy may be extracted. Synthetic jet actuators (SJA)s are used along with the unique geometry of the MG airfoil to control flow separation and amplify the LCO and energy generation potential of the system. The discussed wind energy harvesting scheme could provide flexibility in allowing installations previously unsuitable to wind turbines due to geometric or low wind velocity …

Passenger Traits That Predict The Bystander Intervention Model Steps During An Inflight Assault On A Flight Attendant, Michael Pettit

Doctoral Dissertations and Master's Theses

Every major U.S. airline has experienced a violent inflight assault on one of their flight attendants. The problem is becoming more widespread, but industry leaders have few coping strategies. The first step toward addressing the issue is understanding the various aspects of the event, including the actions of other passengers (bystanders) who may witness the assault. There is ample literature on bystander reactions to similar events such as bullying, medical emergencies, injuries, and violent attacks, but none dedicated to a flight attendant assault or passenger reactions to it.

At the core of bystander action is the bystander effect, which postulates …

Implementation Of Path Planning Methods To Detect And Avoid Gps Signal Degradation In Urban Environments, Ayush Raminedi

Doctoral Dissertations and Master's Theses

In the modern world, various missions are being carried out under the assistance of autonomous flight vehicles due to their ability to operate in a wide range of flight conditions. Regardless, these autonomous vehicles are prone to GPS signal loss in urban environments due to obstructions that cause scintillation, multi-path, and shadowing. These effects that decrease the GPS functionality can deteriorate the accuracy of GPS positioning causing losses in signal tracking leading to a decrease in navigation performance. These effects are modeled into the simulation environment and are used as part of the path planning algorithm to provide better navigation …

Adaptive Control For A Class Of Nonlinear, Time Varying Rotational Systems, John Zelina

Doctoral Dissertations and Master's Theses

Aerospace systems often exhibit nonlinear, time varying dynamics. Expansive mission profiles, fuel burn or transfer and payload deployments or slung loads can supply additional complexity that can excite the plant dynamics and result in undesirable performance. Because of these often unknown dynamical effects in aerospace systems, an emphasis is placed on controller robustness as significant safety risks are present. Due to the difficulty of predicting uncertainties, robust control can be achieved in two distinct ways. The first approach is to design a control law to be tolerant to a large amount of uncertainty, and the second is to design a …

The Use Of Virtual Reality Training Environments For Procedural Training In Fourth-Generation Airliners, Mark Edgar Mccullins

Doctoral Dissertations and Master's Theses

This study examined the effectiveness of using virtual reality training environments for procedural training in fourth-generation airliners. Its goal was to assess whether the training outcomes from a recurrent training course for FAA certificated Airframe and Powerplant (A&P) technicians, which used a Full Flight Simulator (FFS) to deliver and assess training, differed from the same training delivered using a Virtual Reality (VR) device.

The study used an experimental design with three groups and two within-group measures of training effectiveness. The control group followed the current training program and was assessed in the FFS, while the second group was trained using …

State Omniscience For Cooperative Local Catalog Maintenance Of Close Proximity Satellite Systems, Chris Hays

Doctoral Dissertations and Master's Theses

Resiliency in multi-agent system navigation is reliant on the inherent ability of the system to withstand, overcome, or recover from adverse conditions and disturbances. In large part, resiliency is achieved through reducing the impact of critical failure points to the success and/or performance of the system. In this view, decentralized multi-agent architectures have become an attractive solution for multi-agent navigation, but decentralized architectures place the burden of information acquisition directly on the agents themselves. In fact, the design of distributed estimators has been a growing interest to enable complex multi-sensor/multi-agent tasks. In such scenarios, it is important that each local …

Initial Orbit Determination Of Uncooperative Satellites Using Particle Swarm Optimization From The Point Of View Of A Novel Observer Orbit, Taylor Yow

Doctoral Dissertations and Master's Theses

Initial orbit determination is an incredibly valuable tool in the field of space situational awareness (SSA). As the number of launches increases every year, more objects are being put into space around the Earth and with political tensions mounting between certain space-accessing countries such as the United States of America (USA), Russia, and China, the number of satellites whose orbits are unknown to a political rival are increasing as well. In this research, orbit estimation of uncooperative target satellites from the point of view of novel orbits using particle swarm optimization (PSO) algorithm is explored. Two cost functions for the …

Trustable Adaptive Controllers For Multi-Agent Systems With Actuator Dynamics, Atahan Kurttisi

Doctoral Dissertations and Master's Theses

Multi-agent systems have become a powerful tool for a wide range of applications due to the effective and cheap solutions they offer. Especially during the last decade, they have impacted a wide array of civilian and military applications (e.g., surveillance, reconnaissance, and payload transportation). However, they suffer system anomalies due to the operational and material conditions, which yields degraded performance or even instability. Hence, this dissertation investigates the distributed adaptive control design process for uncertain multi-agent systems with scalar and high-order dynamics in the presence of unknown control effectiveness and actuator dynamics. First, it provides an approach for driving a …

Honing The Craft Of Qualitative Data Collection In Extreme Contexts, Payal Sharma, Madeline Toubiana, Kisha Lashley, Felipe Massa, Kristie M. Rogers, Trish Ruebottom

Management Faculty Research and Publications

Over the past several years, there has been ongoing dialog within our academic journals and the profession regarding the value of examining extreme, unconventional, or unsettling contexts in management research. These conversations have highlighted that perhaps more than ever, we as a society are facing unprecedented grand and perplexing challenges, and conducting research in unconventional or extreme settings can reveal complex dynamics or relationships that we may not understand otherwise. Less discussed, however, are methodological considerations for conducting research in unique contexts. As such, we aim to extend the explicit discussion of effective strategies for scholars who consider the perspectives …

The Last Colony Of The Mind: Narrative, Legal Advocacy, And The Decolonization Of Legal Knowledge, Ayodeji Kamau Perrin

Faculty Scholarship

Philippe Sands’ The Last Colony¹ tells the story of how Chagos Islanders won the right to return to the lands of their birth through a 2019 Advisory Opinion of the International Court of Justice (ICJ).² In 1965, while the United Kingdom stood in the midst of conceding to the independence claims of myriad anti-colonialists throughout its imperial holdings, it took the anachronistic step of creating a colony—the British Indian Ocean Territory (BIOT).³ In flagrant violation of UN Resolution 1514,⁴ the United Kingdom detached the Chagos Archipelago from the colony of Mauritius. And between 1967 and 1973, …

Tort Theory And The Restatement, In Retrospect, Keith N. Hylton

Faculty Scholarship

This is my third paper on the Restatement (Third) of Torts. In my first paper, The Theory of Tort Doctrine and the Restatement (Third) of Torts, I offered a positive economic theory of the tort doctrine that had been presented in the Restatement (Third) of Torts: General Principles, and also an optimistic vision of how positive theoretical analysis could be integrated with the Restatement project. In my second paper, The Economics of the Restatement and of the Common Law, I set out the utilitarian-economic theory of how the common law litigation process could generate optimal (efficient, wealth-maximizing) rules and compared …

Chronic Pain And Opioid Addiction - Conservative Options?, Jessy Johnson

Aurora GME

No abstract provided.

Creation Of Bound Half-Fermion Pairs By Solitons, Sapan Karki, Brett Altschul

Faculty Publications

In the presence of topologically nontrivial bosonic field configurations, the fermion number operator may take on fractional eigenvalues, because of the existence of zero-energy fermion modes. The simplest examples of this occur in 1+1 dimensions, with zero modes attached to kink-type solitons. In the presence of a kink-antikink pair, the two associated zero modes bifurcate into positive and negative energy levels with energies ±ge^-gΔ, in terms of the Yukawa coupling g≪1 and the distance Δ between the kink and antikink centers. When the kink and antikink are moving, it seems that there could be Landau–Zener-like transitions between these …

The Inextricability Of Students’ Mathematical And Physical Reasoning In Quantum Mechanics Problems, Kaitlyn Stephens Serbin, Megan Wawro

School of Mathematical & Statistical Sciences Faculty Publications

Reasoning with mathematics plays an important role in university students’ learning throughout their courses in the scientific disciplines, such as physics. In addition to understanding mathematical concepts and procedures, physics students often must mathematize physical constructs in terms of their associated mathematical structures and interpret mathematical entities in terms of the physical context. In this study, we investigate physics students’ reasoning about mathematics in relation to physics content addressed in two quantum mechanics problems. Through qualitative analysis of interview data from twelve students, results show that 1) students use intricate, nonuniform problem-solving methods with reasoning that moves fluidly between structural …

Analysis Of Fast-Cured Plastic Scintillator Variations, Andrew K. Nesbitt, John W. Mcclory, Juan J. Manfredi, Andrew W. Decker

Faculty Publications

Organic plastic scintillators are widely used in a variety of homeland security applications, most commonly as detectors for radiation portal monitors due to their relative low cost, physical robustness, and fast-timing properties. However, plastic scintillators also typically provide lower light yields and photon sensitivity compared to other detector material alternatives, so many studies over the past two decades have sought ways to overcome these shortfalls. Research recently conducted at the Air Force Institute of Technology and Oak Ridge National Laboratory demonstrated that photocuring novel plastics offered a viable method for producing fast-curing plastic scintillators (FCPSs). These formulations included an acrylic …

3rd Place Contest Entry: Cultural Attitudes Towards Ethnic Cuisine In Italy, Rachel Berns

Kevin and Tam Ross Undergraduate Research Prize

This is Rachel Berns' submission for the 2024 Kevin and Tam Ross Undergraduate Research Prize, which won third place. It contains their essay on using library resources, their bibliography, and a sample of their research project on cultural attitudes toward ethnic cuisine in Italy.

Rachel is a fourth-year student at Chapman University, majoring in Health Sciences. Their faculty mentors are Dr. Anuradha Prakash and Dr. Sara Mattavelli.

Barriers To Escape: How Homelessness And Drug Addiction Prevent Women From Escaping Sex Trafficking And Commercial Sex, Laura J. Lederer, Mckamie J. Chandler, Stanley Stinson

Dignity: A Journal of Analysis of Exploitation and Violence

Victims of sex trafficking and women purportedly involved in prostitution voluntarily face a complex web of interconnected challenges when attempting to escape their current circumstances. By analyzing the shared and distinct challenges faced by these women, the paper aims to inform policymakers and service providers, offering recommendations to empower women seeking to escape exploitation through multidisciplinary and interconnected networks of providers. This study surveyed 74 women in Detroit, Michigan, using nonprobability convenience sampling over a 10-month period in 2020. It compared three groups of women who self-reported as victims of sex trafficking, women who voluntarily engaged in some form of …

New Genera And Species Of Caulobacter And Brevundimonas Bacteriophages Provide Insights Into Phage Genome Evolution, Bert Ely, Michael Hils, Aaron Clarke, Maegan Albert, Nadia Holness, Jacob Lenski, Tannaz Mohammadi

Faculty Publications

Previous studies have identified diverse bacteriophages that infect Caulobacter vibrioides strain CB15 ranging from small RNA phages to four genera of jumbo phages. In this study, we focus on 20 bacteriophages whose genomes range from 40 to 60 kb in length. Genome comparisons indicated that these diverse phages represent six Caulobacter phage genera and one additional genus that includes both Caulobacter and Brevundimonas phages. Within species, comparisons revealed that both single base changes and inserted or deleted genetic material cause the genomes of closely related phages to diverge. Among genera, the basic gene order and the orientation of key genes …

Psychometric Evaluation Of The “Providing Validation” Measure In Vascular Anomalies, Bryan A. Sisk, Anna M. Kerr, Amy R. Newman, Dandan Chen, Jennifer W. Mack, Bryce B. Reeve

College of Nursing Faculty Research and Publications

We assessed the psychometric properties of the “providing validation” subscale of PedCOM measures for parents of children with vascular anomalies and adult patients. A total of 139 adult patients and 78 parents completed surveys. The mean score for patients was 3.7 (standard deviation 1.0), and for parents was 4.0 (standard deviation 0.9). “Providing validation” measures demonstrated high internal consistency and good model fit to a unidimensional model for both patients and parents using confirmatory factor analysis. The measures also demonstrated convergent validity with co-administered measures. This study demonstrated the validity of “providing validation” measures for parents and adult patients with …

Effect Of Layer Thickness, Inner Structure, And Implant Angulation On The Accuracy Of 3d Printed Models With Implant Analogs, Omar Elsergany

Dentistry

Objective: This study evaluated the effect of layer thickness, model inner structure, and im- plant angulation on the accuracy of 3D printed models with repositional analogs.

Materials and methods: 126 models designed to receive all-on-4 implant retained fixed den- tal prosthesis were 3D printed. Models were divided into 2 groups (n=63) according to posterior implant angulation (Group 1; 30 ̊ and group 2;45 ̊). The models were then divided into three sub- groups (n=21) according to the printing layer thickness (Group a; 50 μm, group b; 100 μm, and group c; 150 μm). Each subgroup was later subdivided into 3 …

Color Stability And Marginal Adaptation Of Ceramic Veneers Cemented Using Different Composite Resins, Basma Refaat Fayad, Maged Zohdy, Engy Adel Farag, Ghada Hussein

Dentistry

BACKGROUND: The purpose of this study was to compare the color stability and marginal adaption of lithium disilicate veneers before and after thermocycling using various resin composite materials employed as cement. METHODS: Laminate veneer preparation was done on an acrylic tooth according to standardized procedures. The veneer preparations were duplicated into twenty-one dies. The veneers were fabricated from lithium disilicate using the CEREC in Lab system. According to the cement type, the twenty-one die specimens were randomly divided into three equal groups: group I, with light cured adhesive resin cement (N.=7), group II, with owable light cured composite, and group …

Congress's Untapped Authority To Certify U Visas, Elora Mukherjee, Fatma Marouf, Sabrineh Ardalan

Faculty Scholarship

A crucial path to legal status for immigrant victims of crimes is the U visa, which Congress established with strong bipartisan support to protect victims of particular crimes who are helpful to law enforcement. Because the U visa was intended to encourage reporting of crimes, the application requires a certification form to be completed by a federal, state, or local authority that is investigating or prosecuting the alleged offense. Arbitrary and inconsistent certification decisions by state and local authorities make it especially important to identify relevant federal authorities that can serve as certifying authorities for U visas. This Piece argues …

Modeling And Numerical Analysis Of The Cholesteric Landau-De Gennes Model, Andrew L. Hicks

LSU Doctoral Dissertations

This thesis gives an analysis of modeling and numerical issues in the Landau-de Gennes (LdG) model of nematic liquid crystals (LCs) with cholesteric effects. We derive various time-step restrictions for a (weighted) $L^2$ gradient flow scheme to be energy decreasing. Furthermore, we prove a mesh size restriction, for finite element discretizations, that is critical to avoid spurious numerical artifacts in discrete minimizers that is not well-known in the LC literature, particularly when simulating cholesteric LCs that exhibit ``twist''. Furthermore, we perform a computational exploration of the model and present several numerical simulations in 3-D, on both slab geometries and spherical …