Engineering Commons^™

Experimental Testing Of Axially Loaded Fuse Plates Without Continuous Buckling Restraint, Rebekah Elizabeth Higgins

Theses and Dissertations

Current seismic design practice is to design structures to avoid collapse and protect life. Buildings are designed to resist seismic loading through strength and ductility. In moment frames, this ductility traditionally comes from inelastic deformation of beams. Moment frame connections move inelastic deformation away from the column and allow a plastic hinge to form in the beam. This plastic hinge prevents collapse but leaves the building difficult to repair. Some proprietary moment frame connections address this issue with replaceable fuse plate connections. These fuse plate connections move the plastic hinge out of the beam and into the replaceable fuse, allowing …

Ankimedbench: Evaluating Hierarchical Medical Knowledge In Language Model Embeddings, Neel Patel

UNLV Theses, Dissertations, Professional Papers, and Capstones

Despite achieving over 90% accuracy on medical benchmarks, recent studies show physicians cannot effectively leverage language models to improve clinical reasoning. Current benchmarks test isolated factual recall, but clinical practice requires hierarchical navigation through diagnostic categories—starting broad and narrowing systematically from chest pain to cardiovascular pathology to myocardial infarction to specific STEMI types. Existing evaluations cannot measure whether models preserve this taxonomic structure essential for clinical reasoning.

We introduce AnkiMedBench, built from 16,512 medical flashcards used by students preparing for licensing exams. Cards are organized across six hierarchy levels spanning 16 broad medical specialties to 672 specific diseases and conditions. …

Measuring And Modeling Nonlinear Vibrations In Structures With Mechanical Joints, Suzanna Gilbert

Theses and Dissertations

Many assembled structures have bolted or riveted joints. Aside from providing a convenient method of assembly, mechanical joints have an important effect on the structure's dynamic response to its environment. Friction and microslip within the joints help to damp out unwanted vibration. However, the joints also introduce nonlinearity into the response. Most notably, the natural vibrational modes of the structure no longer have constant natural frequencies and damping ratios. Rather, they shift as a function of vibration amplitude. Several methods exist to characterize the dynamics of nonlinear systems, yet they are generally validated on simple benchmark structures, and many still …

Methodological Approaches For Enhancing The Energy Efficiency Of Waste-To-Energy Biogas Systems, Evan Walls

Undergraduate Honors Theses

Diversifying the sources of energy production is a key issue as the world looks to transition to more sustainable energy sources. Anaerobic digestion (AD) of organic waste is one example of waste-to-energy (WTE) methods for energy production that is of particular interest in this clean energy transition because of benefits to both waste management and energy production, supporting the development of circular economies. In this work, I used geographic information systems and experimental methods to identify ways to both minimize the energy inputs and maximize the energy production of WTE biogas systems, to create energy efficient and sustainable systems. I …

Fedchae: Federated Learning With Client Clustering And Hybrid Adaptive Engagement, Chaeeun Park

Electrical and Computer Engineering ETDs

As machine learning adoption expands, data privacy concerns have grown significantly. Federated Learning (FL) addresses this challenge by allowing clients to train locally and share only their model parameters with the server. However, conventional FL methods such as FedAvg suffer from high communication overhead, as all clients must participate in every global round.

This paper proposes FedChae (Federated Learning with Client Clustering and Hybrid Adaptive Engagement) to balance communication efficiency and model accuracy. FedChae alternates between Grouping Rounds, where all clients perform clustering, and Conventional Rounds, where one client per cluster updates the model.

Simulations with 100 clients using Multi-class …

Simulation Of Stress Induced By Laser Heating Of Glass, Austin Marsh Schuberth

Mechanical Engineering ETDs

The purpose of this work is to create a method for accurately simulating the stresses due to heating from femtosecond laser pulses. Our work aims to calculate stress and strain in glass exposed to laser pulses used for laser welding. We simulate the effects of thermal heating, thermal expansion, and the viscoelasticity of glass for a single straight weld bead. The laser heating of K9 borosilicate glass was simulated using Finite Element Analysis (FEA). Thermal models developed by other researchers in earlier work were utilized in calculating the temperatures due to the laser exposure to the glass material. 2D simulations …

Non-Destructive Characterization Of Ion Irradiated Yttrium Hydride For Microreactor Applications, Ryan E. Pena

Nuclear Engineering ETDs

As energy demands increase, nuclear reactors, especially microreactors, become a promising energy source. These reactors run at high temperatures (>280°C), requiring moderators that can endure these environments. Yttrium hydride is a possible moderator, but little is known about the material’s phase stability and hydrogen retention under irradiation. Through the use of a gold ion beam, samples with stoichiometries ranging from 1.6 to 2.0 were irradiated and tested. Through Vickers hardness testing, a model was created showing a correlation between hydrogen content and hardness. Raman spectroscopy showed high temperature and irradiated samples have significant hydrogen loss. XRD quantified this hydrogen …

Sequential Low Dose Proton Irradiation And Nanomechanical Testing To Understand Mechanical And Microstructural Property Changes In Alloy 709, Abhishek Kc

Nuclear Engineering ETDs

Alloy 709, a 20Cr25Ni alloy, is an advanced austenitic steel designed for next generation sodium fast reactors. Preliminary studies have shown the potential of Alloy 709 in sodium fast reactors. In this study, Precipitate Treated Alloy 709 specimens are irradiated with 2 MeV H⁺ at 500 °C from 0.0057 dpa to 1.7 dpa. Electron microscopy characterization techniques are used to understand the effects of radiation on mechanical properties as well as microstructure of Alloy 709. The microstructure did not show formation of voids, amorphization of precipitates, or increase in grain size up to 1.7 dpa. Correspondingly nano-indentation and micro-pillar …

Coupled Adjoint-Based Perturbation Theory For Dynamics And Heat Transfer Multiphysics For Nuclear Transients, Alexis Maldonado

Nuclear Engineering ETDs

Nuclear reactor multiphysics modeling and simulation (M&S) enable advanced reactor design by analyzing how systems will react over time to various configurations, scenarios, and perturbations. However, high-fidelity coupled transient M&S for reactor cores are computationally expensive, making robust analyses challenging. This work develops a Coupled Adjoint-based Perturbation Theory for dynAmIcs and heat traNsfer (CAPTAIN) framework to rapidly quantify the impact of uncertainty to overall transient responses by generating sensitivity coefficients for temperature, power, and delayed neutron precursor concentrations using forward and adjoint solutions. This work presents an initial proof of principle, verified with direct perturbations to several inputs. Furthermore, this …

A Risk-Informed Approach To Performing The Pre-Closure Safety Analysis For The Deep Borehole Disposal Of Radioactive Waste, Jennifer Elizabeth Leute

Nuclear Engineering ETDs

Deep borehole disposal is an emerging concept which involves disposing of radioactive

waste in boreholes several kilometers deep then backfilling to minimize radionuclide

transport and distribute weight. Unfortunately, little documentation exists on borehole

safety case development, especially for pre-closure operations. This study aims to close

this gap by proposing a graded approach matrix based on consequence, maturity, and

complexity. Two case studies are used to demonstrate this application: Hanford CsCl

capsules and spent PWR assemblies. Simulations are used to predict potential for dose

exposure, revealing CsCl capsules have a much higher potential for being above the 5

rem public dose …

Parameter-Efficient Multimodal Adaptation: Ocr-Integrated Lora For Textvqa And Captioning, Karthik Ganesh Malini

Master's Theses

Vision-Language Models (VLMs) have emerged as transformative technologies for multimodal AI, yet they face significant hurdles in processing text-rich images required for enterprise applications like document understanding, medical imaging, and industrial inspection. Current VLMs struggle with accurate text extraction and reasoning, often exhibiting high hallucination rates and poor Optical Character Recognition (OCR) token utilization. To address these limitations, this research presents a comprehensive framework for optimizing parameter-efficient Low-Rank Adaptation (LoRA) fine-tuning strategies on state-of-the-art architectures, including LLaVA-1.5 and BLIVA-FlanT5. Our methodology integrates enhanced OCR token utilization, faithful caption generation, and specific hallucination mitigation techniques. We employ a multi-dimensional evaluation protocol …

Design And Evaluation Of The Influence Of Mutual Induction On Microbial Electrolysis Cell Performance And Biogas Production, Ashley L. Blackwell

Civil Engineering ETDs

Microbial electrolysis cells (MECs) present a pathway for energy recovery in wastewater treatment by converting organic substrates into methane or hydrogen. Traditional MEC designs typically rely on physical electrode contacts and expensive materials, which restrict their scalability. This study introduces the first induction-based MEC that uses mutual inductance between an external copper wrap and an internal coil to generate a fluctuating electrical potential, removing the need for expensive electrodes. The induction-stimulated reactor showed faster total organic carbon removal and a higher CH4/CO2 ratio compared to a conventional anaerobic digester, indicating improved carbon-to-methane conversion, although total gas yield remained similar. Microbial …

Graph Based Planning With Guarantees, Trazon Tyrik Jimerson

Mechanical Engineering ETDs

This thesis presents two graph-based methods with formal guarantees for motion planning and routing. First, the invariant-set motion planner (ISMP), which uses constraint admissible positive invariant (CAPI) sets of closed-loop dynamics, is adapted for spacecraft attitude planning to avoid moving keep-out zones. Contributions include time bounds for maneuvers via exponential stability, a single-stage reachability graph from one-step backward reachable CAPI sets, and its multi-stage expansion to certify node safety over time. Simulations verify safe attitude control with moving obstacles. Second, we formulate a convex optimization problem over a network for evacuation planning with operational constraints such as helicopter capacity and …

Real-Time Frequency Tuning Of Kinetic Energy Harvesters Via System Mass Adjustment, Rahul Adhikari

Mechanical Engineering ETDs

This research presents a method for real-time frequency tuning of piezoelectric kinetic energy harvesters through system-mass adjustment. Custom 3D-printed proof masses with cavity arrays were used to redistribute solid or liquid mass, enabling controlled modification of resonant frequency. Experimental studies using microparticles and liquids—including water, silicone oil, and sodium polytungstate—demonstrated an achievable tuning range of 115.27 Hz with sub-hertz resolution (< 0.1 Hz), confirming precise and repeatable frequency control. Finite-element modeling guided design optimization, while a microfluidic channel system enabled automated liquid filling for real-time operation. A MATLAB-based EH_Tuning application was developed to visualize and predict frequency responses. The combined …

Design And Development Of Evacuated Photovoltaic-Thermal Systems For Efficient Cogeneration Of Heat And Electricity, Behnam Roshanzadeh

Mechanical Engineering ETDs

In conventional PV systems, most of the solar energy is dissipated into the environment as heat. Accordingly, hybrid Photovoltaic-thermal systems have been developed to utilize the waste heat from PV cells for various thermal applications. However, most PVT systems suffer from low thermal performance compared to solar thermal collectors, as the absorber plate in PVT systems is partially or fully covered by PV cells. This dissertation focuses on improving the thermal performance of PVT systems by introducing the evacuated PVT systems.

An evacuated-tube PVT system was designed and simulated for domestic hot water supply. The evacuated-tube PVT system demonstrated 40% …

Analysis Of Heat Transfer And Pressure Drops Associated With Twisted Tube Heat Exchangers, Braden Foderaro

Nuclear Engineering ETDs

Several studies have been done on the effects of twisted tubes in heat exchangers, including the correlations that relate the flow parameters to the heat transfer and pressure drop experienced. These studies are new, with the earliest being performed in 1982. As such, there are many correlations covering only certain flow parameters and geometrical configurations such as the Reynolds number and modified Froude number.

This thesis attempts to cover flow regimes and tube geometries not yet studied and yield correlations. Data are gathered from heat exchangers featuring twisted tubes with water as the working fluid. It is noticed that the …

Recreating Fiber Recruitment With Fiber Recruitment Using Additive Manufacturing, Natalia D. Mciver

Biomedical Engineering ETDs

Injured ligaments are often repaired with tendon grafts which may over or under constrain the joint; there is a need for an artificial graft option with the mechanical properties of a native ligament. Crimped fibers within ligaments allow for recruitment which means the viscoelastic properties of stress relaxation and creep are not inversely related. A feasibility study using ACLs and large-scale crimp models to study viscoelasticity, led to an in-depth analysis of the scapholunate interosseous ligament. Using the Modified Kelvin spring-dashpot model, for describing viscoelasticity with a variable stiffness property (time dependent fiber recruitment), we defined the relationship between creep …

Dynamic Admittance Parameterization For Non-Prehensile Multi-Robot Transport With Optimal Coordinated Planning, Calvin J. Stahoviak

Computer Science ETDs

The Dynamic Admittance Parameterization of Non-Prehensile Multi-Robot Trans- port with Optimal Coordinated Planning (DYNAMO) architecture offers a practical framework for cooperative payload transportation using two robots equipped with nonholonomic mobile bases and four-degree-of-freedom manipulators. Coordinated mobile manipulation is a difficult problem in robotics, and the non-prehensile case is even more challenging than its prehensile counterpart because the robot bases and the payload are dynamically coupled. DYNAMO adapts arm motion in response to interaction forces and generates coordinated base trajectories that account for this coupling. Robust payload transport is achieved through the combination of opti- mal planning and adaptive compliant control, …

Irregularities In The Dynamics Of Large Networks: Cases On Social Networks And The Internet, Dheeman Saha, Abdullah Mueen, Shuang Luan, Afsah Anwar, Yangsun Hong

Computer Science ETDs

Dynamic networks capture evolving relationships among entities, and irregularities in their behavior often signal significant events. This dissertation investigates such irregularities across social and infrastructural networks. First, we analyze Twitter (prior to its rebranding to X) to characterize influencers, introducing a follower-overlap similarity measure that identifies micro-influencers beyond content-based methods.

We then examine election-related irregularities by comparing suspended and non-suspended accounts during the 2020 U.S. presidential election, revealing behavioral patterns linked to misinformation and coordinated manipulation.

Next, we develop an algorithm to infer post-specific diffusion networks, reconstructing who-saw-from-whom pathways for tweets at scale. This method uncovers structural differences in diffusion …

Investigating The Fatigue Behavior Of Inconel 939 And Inconel 718 Through Micromechanical Testing, Mohammad Hossein Shahini

LSU Doctoral Dissertations

A detailed evaluation of fatigue crack growth (FCG) in a silicon-modified Inconel 939 alloy, fabricated via laser powder bed fusion additive manufacturing (L-PBF AM), was performed using cyclic bending tests on pre-notched microscale cantilevers with a cross-sectional dimension of 25 µm × 25 µm. To our knowledge, this study is the first to demonstrate that such microscale cantilever tests can effectively capture both the threshold and Paris-law regimes of FCG, despite the limited specimen size. The precise fabrication of these small-scale specimens allows for controlled fatigue crack propagation relative to the microstructure while minimizing the presence of volumetric defects. Notably, …

Application Of Bimetallic Transition Metal Oxides Electrocatalysts For Li-Co2 Batteries And Li-O2 Batteries, Jianda Wang

Chemical and Biological Engineering ETDs

Li-ion batteries are the dominant commercial rechargeable batteries nowadays, which are used in electronic devices and electrified transportation widely. However, undesirable energy density of Li-ion batteries prohibits them from meeting requirements of new generation electronic devices. Therefore, it is important to find more alternative electronic energy storage systems with higher capacity. Fortunately, Li-CO2 batteries, featured high capacity and ability to convert CO2, have become a promising candidate to replace Li-ion batteries. In addition, Li-O2 batteries also attract people’s attention due to their high energy density and low cost. However, Li-CO2 batteries and Li-O2 batteries both face challenges of terrible cycle …

Thermally Stable And Regenerable Catalysts For Alkane Dehydrogenation, Ryan Alcala

Chemical and Biological Engineering ETDs

Shale gas upgrading reactions have gained much interest since production dramatically increased around 2010. These reactions occur at high temperatures (600°C +) where undesired processes like sintering and/or coking often occur. It is of interest to use materials like ceria as a catalyst support in these alkane conversion reactions, but ceria is prone to losing active surface area through sintering. It is also of interest to understand the behavior of PtMn and PtZn intermetallics for propane dehydrogenation as they have been identified as some of the best catalysts by theory-based prediction in literature. This manuscript explores ways of utilizing ceria’s …

Empowering Wireless Mesh Uav Networks Through Software-Defined Networking, Hieu Quang

Electrical and Computer Engineering ETDs

Unmanned Aerial Vehicles (UAVs) have been widely deployed in applications such as environmental monitoring, disaster response, and surveillance. Effective coordination between UAVs depends on low-latency inter-UAV communication to exchange state information, decisions, and other critical data. UAV networks are inherently dynamic which necessitates a framework capable of handling scenarios such as traffic re-routing, and resilience to communication failures. To address the challenges of managing dynamic UAV networks, this thesis proposes a dual network approach composed of three main components. First, the Better Approach to Mobile Ad-hoc Networking (BATMAN) protocol is used to enable communication among UAVs. Second, the OpenFlow protocol …

“Bridging The Gap To Midwave Infrared Event-Based Sensors: Design, Sensitivity, And Radiation-Hardness Characterization Of A Single-Pixel Iii-V Event-Based Infrared Sensor For Space Applications, Zinah M. Alsaad

Electrical and Computer Engineering ETDs

Event-based sensing presents a revolutionary paradigm shift for next-generation space surveillance systems, where power consumption is an ever-worsening constraint as temporal resolution demands increase. In addition to reduced power consumption, low latency, and wide dynamic range, the event-based sensor fundamentally only produces data when there is a change in illumination from which events are generated; no data is produced if the scene remains static. With their event-based datastream being inherently focused on the dynamic information of the scene, they are particularly well-suited to machine vision and autonomous sensing applications. While these sensors have many compelling advantages, there are presently no …

Emulation Of Orbital Dynamics And Control Of Fully Actuated Seven-Axis Prismatic Joint Systems, Bennett Russell

Electrical and Computer Engineering ETDs

This thesis details the system modeling, design, control, simulation, construction, and testing of a fully-actuated seven axis prismatic joint system created for the primary purpose of emulating on-orbit maintenance tasks. Additionally, it seeks to further research of space-based control schemas and investigate stiction as a case study with a mountable hybrid hinge system that emulates stiction. Controllers are evaluated under common limits and metrics, including time to escape, overshoot, mechanical work, and limit-exceedance counts. Comparisons span a PID baseline, deterministic MPC/MPPI, and a probabilistic POMDP policy. Results verify the emulator and hybrid hinge meet the intended design criteria and show …

A Bump Hunting Approach To Finding Interpretable Data Pockets, Tushar Ojha

Electrical and Computer Engineering ETDs

This dissertation approaches the problem of extracting simple interpretations from local regions of data. This is sometimes called bump hunting because the local regions of interest have a high concentration of a particular output value. This work develops a bump hunting method for discrete-valued tabular data where each bump is modeled by a rectangular region of the input data space so its rule-based description admits a simple logical interpretation that can inform decisions. This method is designed for labeled data where each input feature has a distinct meaning that may or may not be related to the output, and the …

Recovery Of High Energy-Value Materials From Mine Wastewater, Zainab Nasrullah

Graduate Theses & Non-Theses

The increasing global demand for high-energy-value materials (HEVM), such as rare earth elements (REEs), copper (Cu), nickel (Ni), cobalt (Co), and lithium (Li), coupled with their limited availability and environmental concerns associated with traditional mining methods, necessitates the development of alternative and sustainable recovery strategies. Wastewater streams from industrial processes, mining operations, and electronic waste treatment represent untapped reservoirs of these valuable materials. Research is proposed to develop sustainable, cost-effective, and scalable methods for selectively recovering HEVM from mine wastewater (Berkeley Pit, Montana). Two innovative approaches, the adsorption process using functionalized adsorbent and solvent extraction (SX) using organic or hydrophobic …

Geologic And Geochemical Investigation Of The Ruby Graphite Deposit, Mikayla Taylor

Graduate Theses & Non-Theses

The Ruby Graphite project (RGP, also known as the Crystal Graphite deposit) is located in the southern Ruby Mountains, Beaverhead County. The deposit contains coarse-grained and highly crystalline graphite, which is a sought-after critical commodity in today’s global economy. The graphite is hosted by high-grade meta-sedimentary and meta-igneous rocks that reached peak metamorphism during the ~ 1.7 Ma Big Sky Orogeny. In this study, samples were collected from outcrops, mine dumps, and new (2023) drill core from the Ground Hog and Bird’s Nest locations. Rock types include calcitic marble, biotite-garnet schist, pegmatite, diopside-rich skarn, altered ultramafic intrusions, and a possible …

Development And Evaluation Of Wireless Monitoring Systems For Touchless Respiratory Monitor Validation, Dustin Marquardt

Graduate Theses & Non-Theses

The Touchless Respiratory Monitor (TRM) is a non-invasive system that uses contactless methods to measure respiratory rate and tidal volume. The main technologies employed are LiDAR for tidal volume measurement and a thermal camera for respiratory rate monitoring. These novel methods require validation against established techniques such as capnometry and respiratory inductance plethysmography. Commercial respiratory monitoring equipment is often expensive and dependent on proprietary software, creating barriers to widespread use. To address this, a custom, modular, and low-cost evaluation system was developed to streamline the validation of the TRM. The prototype system integrates a pulse oximeter, capnometer, spirometer, and respiratory …

Recycling Ndfeb Magnets I: Production Of Ree Fluorides By A Novel Lpc Process, Isaac Joseph Cobbinah

Graduate Theses & Non-Theses

Neodymium-iron-boron (NdFeB) magnets account for over 60% of global magnet sales and are widely used in high-tech, military, and clean-energy applications (Ormerod, 2022). However, they contain critical rare earth elements such as Nd, Pr, and Dy which poses supply chain and geopolitical risks for country like the United States, which rely extensively on foreign sources. Recycling end-of-life NdFeB magnets provides a sustainable solution that diminishes environmental impact, strengthens supply security, and supports stable domestic production of important rare earth elements. A three-stage process has been developed for recycling the REE-content of NdFeB magnets. While the focus is on neodymium (Nd), …