Digital Commons Network^™

Heat Transfer Of Additively Manufactured Turbine Alloy Blade Tips With Different Surface Enhancement Post-Processing Methods, Morgan Tatge

Theses

The investigation results presented here consider the heat transfer characteristics of seven different turbine blade tips. Six of the blades are additive manufactured with GRX-810, followed by different surface enhancement post processing techniques. Those techniques include as built, abrasive flow machining, chemical polishing with chemical mechanical polishing, micromachining, chemical polishing, and electropolishing. The seventh blade is machined with 1016 steel. These procedures give a different surface texture roughness for each blade. A transonic linear cascade within a transonic/supersonic wind tunnel is utilized. The impulse response method is employed to determine heat transfer coefficient distributions for the blades. The Tad/T0i temperature …

Design, Development, And Analysis Of A Pulsed Power System Using A Thyristor To Fire A Coaxial Plasma Gun, Neil P. Laya

Theses

A first of a kind fiber-optically controlled and thyristor switched coaxial plasma gun pulsed power system has been designed, built, and fired at up to 2 kV and 6.4 kA, with a 6.65 MW momentary peak power output from the capacitor. Total system firing jitter from initial digital signal to 90% peak current rise has been measured at 78.15 ns, representing 0.18% of the total pulse time of 44.10 µs. This includes both thyristor turn-on and coaxial plasma gun breakdown. Standard deviation of peak current over repeated firings has been measured to be 21.09 A (0.33%). The system has experienced …

Utilizing Ground-Based Radar Analyses To Investigate Ocean-To-Land Differences In The Tropical Cyclone Wind Profile And Their Impacts On Tornadogenesis, Elizabeth M. Seiler

Theses

On 20 August 2008, the MAX radar was deployed southeast of the Jacksonville, FL WSR-88D radar to monitor the boundary layer before, during, and after the landfall of TS Fay. During the 57-hour deployment, MAX sampled around a tornadic rainband that produced at least one confirmed tornado. To illustrate TCBL changes across a coastal zone, VAD profiles from MAX and KJAX are compared, and a dual- Doppler analysis is performed. One key finding from the DDA was the consistent presence of southeasterly background flow, vertical vorticity, enhanced cyclonic shear zones, and minisupercells throughout the 1650-1725 UTC analysis period. The primary …

Generation Of True Random Numbers With Actively Stabilized, Low Dimensional Chaos, Aidan Barton

Theses

True Random Number Generators (TRNGs) are heavily used and their design often relies on empirical validation from statistical test suites. Reliance solely on empirical observations to estimate entropy rates for cryptographic applications introduces risk, as accurately inferring long-term correlations demands prohibitively large datasets. Empirical validation of TRNGs must be supplemented by strong theoretical backing to justify estimated information theoretic quantities. We present an electronic, hardware TRNG scheme that produces a maximally random output guaranteed from first principles. This TRNG uses a pulse-width based hardware realization of an iterated map that produces physical entropy via low-dimensional chaotic dynamics. The simple dynamics …

A Comprehensive Study On Explainable Artificial Intelligence : A User-Centric, Cognitive Workload, And Feasibility-Driven Analysis, Josiah Taylor

Theses

Explainable Artificial Intelligence aims to open up the “black box” of artificial intelligence, thereby improving user trust, decreasing cognitive load, and improving task performance. As the number of machine learning models has grown, so has the number of explanation methods, making it necessary to select the most suitable explanation method for a given context. However, current selection methods often fail to account for all the factors that contribute significantly to an explanation method’s suitability. This thesis proposes a novel methodology for selecting and evaluating explanation methods. Subjective workload, objective performance, and feasibility are considered. This three-pronged “pitchfork” methodology is put …

Chaos-Based Thumbnail-Preserving Image Encryption, Sara Mog

Theses

As the landscape of image data usage continues to change, cloud services need to store data securely, reliably, and at times maintain a reasonable level of human usability. Thumbnail-preserving encryption (TPE) is a niche area of image encryption research that provides a balance between security and privacy. A TPE scheme encrypts an image in such a way that the thumbnail of the encrypted image is the same as or similar to the thumbnail of the original image. This work presented a chaos-based TPE scheme and explored potential pitfalls encountered when using chaos for encryption. The TPE scheme used a chaos-based …

Development Of A Constitutive Model Free Method To Determine Full-Field Stresses Based Upon Fundamental Physics Principles, Joel David Barnes

Theses

Advances in imaging techniques allow for the determination of full-field displacements and strains during materials testing. However, most analysis techniques rely on strain gages and virtual extensometers instead of utilizing all available full-field data. Those methods that do utilize the full-field strain and displacement measurements, such as Finite Element Model Updating and the Virtual Fields Method, must also rely on a user-defined constitutive material models to relate the stresses and strains. While these methods can provide accurate full-field stresses and insights into complex material behavior in some cases, they are constrained by the fact that they require a pre-selected constitutive …

Gai Research - A Case Study On The Implications Of Generative Artificial Intelligence (Gai) On Teaching Within An Irish Technological University., Moya Cronin

Theses

The rapid emergence of Generative Artificial Intelligence (GAI) has introduced a transformative age of technology, gaining prominent attention in higher education. This mixed-methods case study examined how GAI was understood, applied, and managed within an Irish Technological University at a time of turbulence when no official GAI policies were available as a point of reference. Lecturing and research staff were invited to participate in an online survey (𝑛 = 145) and semi-structured interviews (𝑛 = 8) to share their experiences with GAI technology within the case study university. Lack of guidance was seen to affect staff’s confidence and adoption, but …

Liposomes As A Platform For Cd40 Ligand Presentation For The Purpose Of Feeder-Free B Cell Activation, Sydney Bone

Theses

Improvement of in-vitro culture of immune cells is critical for expanding our understanding of the immune system and advancing the treatment of diseases, whether pathogenic, cancerous, or autoimmune, via cellular immunotherapies. This study aims to develop a feeder-free B cell culture system using biomaterials-based presentation of a critical signaling molecule, namely CD40 ligand (CD40L). Traditional B cell culture methods rely on allogenic feeder cells to present CD40L, but a culture of only autologous cells is preferable for cellular immunotherapies. Previous work of our lab established an effective feeder-free B cell culture system using magnetic microbeads as a synthetic platform for …

Subconscious Warnings As A Safety Mechanism Against Phishing Attacks, Henry Schulz

Theses

Phishing attacks are very common and considerably successful in stealing people’s information, but unfortunately normal security procedures fail to warn the user of their possible dangers. By considering how subliminal messages are very effective in informing people without actively disrupting their attention, a prototype of a browser extension was made by implementing subconscious messages and the elements of an effective warning, in an attempt to subconsciously warn users of possible phishing attempts, with minimal impact on browser performance.

Determination Of Material Deformation At Truly Constant Strain Rates Utilizing Full-Field Stress And Strain Measurements, Derryk Lee Daignault

Theses

The rate sensitivity of materials is an important aspect to consider when designing components; such as in manufacturing processes, aerospace vehicle impacts/propulsion systems, and automobile collisions. Characterizing a material’s rate sensitivity can be expensive and time consuming due to multiple tests being necessary at each given strain-rate to fully characterize the response. This project proposes a methodology to determine the material response at multiple truly constant true strain rates from a single test using non-uniform geometry and the strain localization phenomenon. Finite element simulations using Ansys LS-DYNA are used to design potential new test specimen geometries to induce constant and …

Fault Tolerance In Krylov Subspace Methods, Sandesh Pandit

Theses

The increasing complexity of modern high-performance computing (HPC) systems, with their vast number of processing units and extensive memory hierarchies, introduces significant challenges to system resilience, particularly in the face of soft errors. Krylov subspace methods, which play a pivotal role in solving large-scale sparse linear systems and eigenvalue problems, are iterative in nature and thus susceptible to the propagation of soft errors. In this paper, we examine the fault tolerance properties of two widely-used Krylov subspace methods: the Lanczos method and the Bi- Conjugate Gradient (BiCG) method. Specifically, we analyze the impact of soft errors introduced during the critical …

Neural Acceleration Of Graph Partitioning, Vishvam Patel

Theses

Graph Partitioning is a critical problem in numerous scientific and engineering domains including social network analysis, VLSI design, and many more. Spectral methods are known to produce quality partitions while minimizing edge cuts for a wide range of problems. However, the computational cost associated with the calculation of the Fiedler vector, an eigenvector associated with the second smallest eigenvalue of the graph Laplacian, remains a significant bottleneck. In this paper, we present an neural acceleration approach to spectral bisection partitioning by replacing the traditional eigenvalue calculation with a simple artificial neural network model to approximate the fiedler vector. We demonstrate …

Nonlinear Dynamics And Data Driven Modeling, Mattan Tseng

Theses

The research areas of dynamics and data-driven modeling overlap in existing literature. Some research uses dynamical systems as a test bed while developing new modeling methods. Other papers attempt to use data-driven modeling as a tool to better understand, or potentially predict the behavior of a dynamical system. The primary goal of this thesis is to further the symbiotic relationship between these two research areas. Firstly, this paper provides a concrete example of how a basis function decomposition of the Lorenz system can provide a quantitative performance metric for data-driven modeling methods. Secondly, a novel application of an existing modeling …

Application Of Machine Learning To Predict Ultrasound Wave Propagation In Biphasic Fluid–Solid Media, Jahnavi Dandamudi

Theses

The objective of this thesis is to investigate the application of Machine Learning (ML) algorithms to predict ultrasound wave propagation in the cartilage tissue of the knee joint. The learning data necessary for the ML algorithm has been generated through finite-element method (FEM)-based simulations for solving the Biot theory equations governing the propagation of continuous ultrasound through the cartilage. Specifically, we computed the ultrasound-induced dilatations and displacements in the microscale cartilage that is represented as consisting of four zones, namely the chondrocyte cell and its nucleus, the pericellular matrix (PCM) that forms a layer around the chondrocyte, and the extracellular …

Experimental And Numerical Investigation Of Combined Mechanical, Electrical, And Thermal Response Of Lr61 Alkaline Batteries At Various Loading Rates, Abigail C. Schauer

Theses

Lithium batteries are present in most electronic devices and machines but pose a serious threat to users if they are over heated, over charged, or otherwise physically damaged. In order to better understand the underlying causes of lithium battery fires, testing procedures at various rates of low, intermediate, and dynamic are established with less volatile 1.5 V LR61 alkaline batteries. The various rates are to cover representative loading rates from scenarios ranging from dropping a cell phone a short distance to a high-rate drone collision with an aircraft. Material characterization is also done on the metal casing to better understand …

Efficient Lossless Compression Of Malaria Infected Image Datasets Using Vision Transformers And Deep Autoencoders, Md Firoz Mahmud

Theses

In the field of medical imaging, lossless compression techniques play a critical role in maintaining the fidelity of medical data, while improving the efficiency of data storage and transmission, especially in telemedicine applications. This thesis addresses the development of a novel machine learning-based method for lossless compression of images of erythrocytes infected with malaria. The proposed method has two stages. In the first stage, a Vision Transformer, a computer vision model that can learn long-range dependence, is employed to separate erythrocyte images into two categories: infected and uninfected. This classification stage is essential as it allows the subsequent compression approaches …

Performance Comparison Of Variable Center Body Configurations For A 25 Mm Rotating Detonation Rocket Engine, Kaito Jonathan Durkee

Theses

Rotating detonation rocket engines (RDREs) are propulsion devices that harness circumferentially traveling detonation waves, providing theoretical benefits compared to classical, deflagration-based combustors. Because of the integration challenges posed by typical annular (Center Body, CB) RDREs, a cylindrical (Center Bodiless, CBL) chamber geometry is attractive. To understand the corresponding trade-offs for small-scale devices, the performance and operational characteristics for a 25 mm with removable 15 mm center body are compared using gaseous methane and hydrogen with oxygen, operating at varying equivalence ratios and at a total mass flow rate of 0.076 kg/s and varying mass flow rates at an equivalence ratio …

Analyzing Code Generation By Ai Models: An Anova-Based Study Of Quality, Consistency, And Composite Ranking, Rajavi Gontiya

Theses

As generative Artificial Intelligence(AI) tools become increasingly common in software development, there is a growing need to understand how well these tools perform beyond just producing code that runs. This thesis examines the performance of four popular generative AI models, ChatGPT (GPT-4 mini), GitHub Copilot, Code LLaMA 3.3, and DeepSeek Web, in generating code that is not only functionally correct but also efficient and maintainable. To do this, we tested each model on six real-world-style coding problems sourced from LeetCode, covering a range of algorithmic challenges like dynamic programming, graph traversal, and array manipulation. Using a consistent prompting strategy, we …

Ai Enabled Scrabble Scoring System : Design And Implementation, Aditya Narayan Jha

Theses

The scope of this thesis is to present an AI-powered system for automatically scoring real-world Scrabble games using computer vision and deep learning. To achieve this purpose a DeepLabv3 model is trained to segment the board from top- down images, while an EfficientNet-B0 classifier identifies individual tile characters, including blank and empty tiles. The system continuously tracks the gameplay by detecting newly placed tiles and applies official Scrabble rules to compute scores, including crosswords, bonus tiles, and bingo logic simultaneously. The scoring engine supports multi-move gameplay, player turns, and endgame handling. All moves are visualized with a color-coded board and …

Sidelobe Reductions In Linear And Circular Phased Array Antennas Based On Hybrid Synthesis Techniques, Eli C. Brothers

Theses

The concentration of electromagnetic waves within an angular space is made possible by radiating devices, typically realized in the form of an antenna. Hence, energy emitted or received outside of the intended field of view is manifested in the sidelobes and minor lobes of a radiation pattern, of which sidelobes are commonly responsible for unwanted interference and signal spread. To mitigate these issues, this study seeks to investigate the efficacy of a hybrid synthesis technique based on electrically displaced phase center antenna (E-DPCA) and partially-tapered methods in reducing the sidelobes of linear and planar arrays by optimizing the excitations of …

Evaluation Of Strain-Rate Sensitivity Of 3k70pw/Inf114 Woven Fiber-Reinforced Composite Material, Elias James Gerstein

Theses

Fiber reinforced composites have seen continued use in aerospace and automotive industries due to their inherent high strength-to-weight ratios, which makes them ideal choices for vehicles where fuel economy is an important design factor. However, it is necessary for structures in these industries to preserve the life and safety of passengers in the event of a crash; thus, crashworthiness of these vehicles must be tested. Many finite element material models for simulating composite materials exist, but few take strain rate effects into account, which is important for accurate modeling of dynamic crash scenarios. LS DYNA MAT_213 is a material model …

An Evaluation Of The Idm Car-Following Model : Simulation And A Dynamical Systems Perspective, Trevor Mcclain

Theses

The Intelligent Driver Model (IDM) is a car-following model that has existed since the early 2000s, existing as one of the most widely used follow-the-leader models to simulate safe and realistic driver behavior. In this work, the IDM is used to evaluate the suitability of ROS 2-Gazebo for vehicle simulation, showing that significant non-determinism is present within the simulation. Additionally, we evaluate the effects of delay and an inserted Followerstopper car following model on the traffic dynamics of the system. Specifically, the generation of stop-and-go waves in idealized traffic from a dynamical systems perspective is examined. We also show that …

Exploration Of Various In-Space Fuels With Differing Characteristic Timescales For Small-Scale Rotating Detonation Rocket Engines, Raj Tejas Dave

Theses

This thesis summarizes the performance of a small-scale rotating detonation rocket engine (RDRE) using methane or hydrogen as the fuel with oxygen as the oxidizer. Specifically, a 25 mm RDRE with a 5 mm annular width and 31.2 mm length is experimentally evaluated at varying equivalence ratio for a fixed total mass flow rate of 0.076 kg/s, as well as varying total mass flow rate for fixed equivalence ratios of 1.25 and 1.00. Experimental measurements for the hot-fire tests include thrust, chamber pressure, specific impulse, and detonation mode parameters. For both sensitivity studies, hydrogen outperforms methane with a peak thrust …

Evaluating The Accuracy Of Johnson-Cook Strain Rate Sensitivity For Fcc Aerospace Structural Materials, Sydney Carlota Resnick

Theses

Understanding aerospace materials’ strain rate sensitivity is crucial for accurate designs and analysis for structural performance in dynamic loading conditions, such as rocket launches, airplane collisions, and debris impacts. Three common aerospace face-centered cubic (FCC) metals are evaluated through various strain rate tests and FEA and simulation modeling. Quasi-static and intermediate tests are performed on a hydraulic load frame, and dynamic tests are run on a split-Hopkinson pressure bar, all in tensile motion. This covers the range of strain rates from 1x10-3 s-1 to 1x103 s-1. Results reveal little strain rate sensitivity at room temperature for A286 steel and AL7075 …

Heat Transfer And Aerodynamic Losses Caused By Additively Manufactured Turbine Blades Enhanced By Micro-Machining And Chemical Polishing, Mason Hancock

Theses

As turbine engines are pushed to operate at higher temperatures and pressure ratios, turbine blades are forced to interact with more extreme conditions. Additive manufacturing (AM) offers new possibilities for meeting these challenges by allowing the fabrication of complex shapes from advanced materials like GRX-810, an alloy designed to maintain strength and durability at extreme temperatures. However, one of the trade-offs with AM is its inherently rough surface finish, which can vary depending on how the surface is treated after printing. This thesis investigates how different surface treatment methods, including micromachining and chemical polishing, as well as the untreated, as-built …

Optimizing Reliability And Design Efficiency Of Liquid Rocket Engines : A Structural Margin Approach For The Early Design Lifecycle, Mason Tudor

Theses

This thesis introduces a reliability-based design methodology aimed at mitigating costs incurred during the Test-Fail-Fix cycle for Liquid Rocket Engines (LREs) by addressing the limitations of the standard Factor of Safety (FoS) approach. By integrating a neural network informed by a structural model into a Bayesian framework for uncertainty quantification, the methodology enables the characterization of structural margin and early analysis of failure risks in the design lifecycle. A generalized 3D component geometry is subjected to typical LRE loading environments within Finite Element Analysis software to gather data for stress and strength distributions. These distributions serve as a foundation for …

Motherhood Or Work: Why Not Both? Representations Of Femininity In Australian Wartime Radio Serials, Emma Price

Theses

War is a gendering activity. As media is one of the many sites where gender is constructed, this study aims to investigate through a discourse analysis of serials produced by women for radio in the 1940s, the ways these programs represented or challenged social and cultural expectations placed on women. The themes female dramatists explored through the genre of radio serials, and the statements these programs made about life as a woman during the Second World War, are under-researched areas in Australian scholarship. While it must be acknowledged that the war was not a turning point in the status of …

Digital Threads: Fashion Design With Clo3d, Maya Herring

Theses

CLO3D (CLO) has emerged as a prominent software service within the fashion industry, molding the conceptualization and development of 3D fashion designs. By eliminating the constraints of customary manufacturing processes and real-life production costs, CLO equips designers with tools to bring their fashion garments and designs to life. This study aims to explore the capabilities of CLO software by developing five digital bridal dresses while also examining the learning curve, challenges, and benefits associated with its usage. The objective is to identify how CLO can provide aspiring fashion designers with the tools to produce high-quality designs without traditional training.

By …

Machine Learning And Artificial Intelligence Models And Techniques In Modern Power Grid Communication Architecture, Majid Jamal Majid Salim Almheiri

Theses

Smart grid is evolving in different phases and artificial intelligence (AI) models are also the part of it. In the recent developments of Smart grid system there are research areas which are left unaddressed specifically in privacy techniques, scalability, more efficient data processing techniques. This Thesis highlights the research gaps on smart grid development across various integration phases. In the initial phase of Smart grid development, challenges included scalability issues in Machine-to-Machine (M2M) communication, communication delays affecting voltage stabilization and high computational costs in implementing Genetic Algorithm (GA)-based grid state estimation are covered in this review report. Review is further …