Engineering Commons^™

Gene Mutation And Chemotherapy Response In Azoxymethane Induced Colorectal Tumors, Maya M. Vance

Biomedical Engineering Undergraduate Honors Theses

Colorectal cancer research is a field of increasing importance as disease prevalence continues to increase over time. In looking at the origin of the disease, a driver gene known as p53 is of particular interest for its role in the stimulation of the mutated Wnt pathway. Developing as a missense-type mutation, this gene that ordinarily functions as a tumor suppressor is investigated as a gene of interest for tumor development. In this study, a mouse model was used to examine the development of colorectal cancer with a total of n=34 samples, including n=9 tumors and n=25 colons. The concentration of …

Optimizing The Effects Of Yoda1 And Assessing The Effects Of Mrna Silencing Of Piezo1 Gene In Mesenchymal Stem Cells, Addison R. Mclaughlin

Biomedical Engineering Undergraduate Honors Theses

Mesenchymal stem cells (MSCs) are multipotent adult stem cells that are capable of differentiating into various skeletal tissues, making them promising candidates for regenerative medicine. A critical factor influencing their differentiation potential is mechanosensitivity, the ability to respond to mechanical stimuli. The mechanosensitive calcium ion channel PIEZO1 has emerged as a key regulator in this process, particularly in osteogenic differentiation. This study investigated the role of PIEZO1 in MSC osteogenesis through pharmacological activation using YODA1 and gene silencing via siRNA. Human bone marrow-derived MSCs were cultured and induced for osteogenic differentiation under varying concentrations and durations of YODA1 treatment. Alizarin …

Fabrication And In Vitro Biocompatibility Assessment Of Composite-Coated Magnesium Materials, Bryce Williams

Biomedical Engineering Undergraduate Honors Theses

This study provides a comparative assessment of the corrosion, morphology, and biological properties of four of the most promising coating methods for magnesium in biomedical applications, namely micro-arc oxidation (MAO), graphene oxide (GO)-containing MAO coating, MAO/sol-gel composite coating, and MAO/polycaprolactone (PCL) polymer dip coating approaches. Despite the abundance of research focused on these promising approaches, there is a notable lack of comparative studies evaluating their properties. To this end, the investigated composite coatings are ZK60+MAO, ZK60+MAO/GO, ZK60+MAO/Sol-gel, and ZK60+MAO/PCL composite coating. Several tests were used to assess various properties of the prepared groups such as in vitro corrosion characteristics, surface …

Insert Creation To Mimic Blood Vessels In Gel Phantoms, Courtney Bloom

Biomedical Engineering Undergraduate Honors Theses

Gel phantoms are commonly used in research settings due to their ability to mimic soft tissue. Creating these phantoms usually involves 3D printing an insert, embedding it in gel, and then washing the insert out. Polyvinyl alcohol (PVA) is typically used as the insert material, but it often swells and deforms the gel during the washout process. Aquapour, a water-soluble material, was investigated as a potential replacement for PVA. Unlike PVA, Aquapour comes in a powdered form that can be mixed with water to create a castable slurry. To create molds to cast Aquapour, SolidWorks was used to design two …

Experimental And Theoretical Fracture Analysis Of Additively Manufactured Orthotropic V-Notches, Venkata Siva Sainath Bavapuram

Theses and Dissertations

This study presents a comprehensive investigation into the fracture behavior of additively manufactured orthotropic V-notched components made of Acrylonitrile Butadiene Styrene (ABS) material. The research integrates both theoretical and finite element approaches to evaluate stress intensity factors (SIFs) in Modes-I and II, which are fundamental in characterizing stress field distributions around notches under applied loading conditions. Unlike isotropic materials, where stress fields depend only on geometry of the component, the anisotropic nature of 3D-printed ABS introduces a dependency on material properties that necessitate different approaches to include anisotropy of the material.

Tensile specimens are 3D-printed with specific material orientations to …

Characterizing Human Mobility Patterns In Saudi Arabia Using Cellular Data, Meshal Alnefaie

Theses and Dissertations

The study analyzes human mobility in Saudi Arabia. Using crowd-source data, Riyadh mobility is analyzed to find trends and highlight mobility patterns of individuals in Riyadh. Then, the mobility of Riyadh is compared with that of Jeddah and Dammam in a similar data collection and analysis. Four mobility metrics are utilized: Number of Visited Locations (NLOC), Number of Unique Locations (NULOC), Radius of Gyration (RGYR), and Distance Traveled (DTRV). The results show interesting outcomes about individuals in the three cities. Although these cities are far from each other, they observe the same mobility patterns. These findings have the potential to …

Towards Visual Inertial Navigation With Fixed Tetrahedral Targets, Joao Leonardo Silva Cotta

Theses and Dissertations

This dissertation presents a robust method for 6DoF position estimation under impaired visual conditions utilizing a minimum 4-point Perspective-n-Point (P4P) solver designed for tetrahedral targets. Using SO(3) × R 3 instead of SE(3), the method uses a Lie group-based formulation to discriminate between rotation and translation, thereby enabling computationally efficient, resource-conscious op- optimization while preserving correct geometric behavior. Designed using the contemporary C++17 library ShomerTarget, the solver is analytically formulated and assessed under pragmatic robotic conditions. Particularly in low-light and high-dynamic environments, experiments on embedded systems, UAVs, and NASA’s Astrobee show that the proposed solver attains enhanced accuracy compared to …

Development Of A 3-Dof Contactless Magnetic Joint Actuator, Elle Whitney

Theses and Dissertations

The magnetic joint actuator is a relatively recent research technology that expands on the brushless DC motor to encompass rotation in three degrees-of-freedom. These actuators involve a stator with a series of electromagnetic coils oriented normal to a spherical permanent magnet rotor which can be controlled by modulating the current of the stator coils. The development of a magnetic joint actuator that operates without a physical connection between the stator and the rotor has wide applications for robotics in dust-sensitive environments, where a device with bearings would otherwise falter. This work details the design, sensing, and control of such a …

Experimental And Theoretical Fracture Analysis Of Rift Manufactured Carbon Fiber-Vinyl Ester Lamina, Daniel Joseph Longo

Theses and Dissertations

This thesis investigates the fracture behavior of unidirectional carbon fiber-vinyl ester (CFVE) laminates manufactured using the Resin Infusion with Flexible Tooling (RIFT) process, a cost-effective alternative to autoclave-based fabrication methods. Composite materials like CFVE are increasingly adopted in high-performance applications due to their high strength-to-weight ratio and corrosion resistance; however, their anisotropic nature presents challenges in predicting crack initiation and propagation. To address this, a comprehensive approach combining experimental testing, finite element modeling (FEM), and classical fracture mechanics was employed. Orthotropic mechanical properties were first determined through tensile and shear tests, providing critical properties for FEM simulations. A series of …

Alternative Robust Design Formulation And Exploration Strategies For Managing Uncertainties In The Realization Of Complex Engineering Systems, Pooja Mukundan

Theses and Dissertations

The design of complex engineered systems often relies on simulation-based models, which inherently introduce uncertainties. Managing these uncertainties is critical to ensure robust system performance. From a decision-based design (DBD) perspective, robust design metrics such as the Design Capability Index (DCI) and Error Margin Index (EMI) are employed to formulate and solve problems under uncertainty. However, existing formulations of these metrics rely on first-order Taylor series approximations for variance estimation, which are often inadequate in the presence of highly nonlinear or multimodal performance functions.

This thesis proposes alternate formulations of DCI and EMI, which use the multiple-point method of variance …

Autonomous Defect Detection In Additive Manufacturing, John Samuel Poindexter Iv

Theses and Dissertations

Additive manufacturing (AM) is the process of creating a product by applying layers of material to build up to the final product. AM has revolutionized the field of manufacturing and has allowed more complex products to be manufactured at reasonable cost, quicker manufacturing time, and optimized material usage. Traditional forms of manufacturing were based on subtractive manufacturing, where by a product would be created by removing material from its source. AM is a new manufacturing process and faces significant challenges when it comes to manufacturing due to defects. Defects can vary from type and severity and can overall weaken or …

Expressive And Interpretable User Engagement Prediction Using Multivariate Survival Processes, Akshay Aravamudan

Theses and Dissertations

The ability to characterize how information diffuses online is of paramount importance to stakeholders that are interested in tasks such as proposing solutions for mitigating and countering dis/misinformation, predicting user engagement of content in social media, planning marketing campaigns to roll-out products and planning dissemination of political campaign messaging among others. One such facet of learning the dynamics of information diffusion is the ability to predict user engagement or the popularity of a single piece of information as it spreads through an online medium. Existing works in this regard mainly either obfuscate user level information or utilize frameworks that are …

Regulatory Compliance Standards And Power System Reliability: A Study On Inverter-Based Resources, Pirouz Honarmand

Graduate Theses and Dissertations

The increasing penetration of renewable energy, particularly inverter-based resources (IBRs), has reshaped the dynamics of modern power systems. This thesis investigates the impact of regulatory compliance, especially frequency ride-through requirements under NERC PRC-029-1, on the performance and reliability of interconnected multi-area systems. Using a MATLAB/Simulink-based state-space model built on the foundational structure proposed by Murty [31] and augmented with advanced control methods such as Linear Quadratic Regulator (LQR) control from Mackey and McCann [32] and further refined in the context of IBR damping by Alsarray and McCann [33], we explore three configurations of a three-area load frequency control (LFC) system. …

Survival Signature Estimation Using Optimization And Monte-Carlo Simulation For K ≥ 3 Classes Of Nodes On Two-Terminal Networks, Md Sazid Rahman

Graduate Theses and Dissertations

This research develops an efficient approach to estimating survival signatures for two-terminal networks with more than two classes of components. Recently, the survival signature has gained substantial attention in the literature on network reliability estimation due to its unique separability property, which enables passing the network topology information independent of the failure distribution of the components. Following recent results from the literature, estimating the two-terminal survival signature by Monte Carlo simulation entails solving a multi-objective maximum capacity path problem on a two-terminal network in each replication. We adapt a multi-objective Dijkstra’s algorithm from the literature to construct the set of …

Intelligent Crowdsourcing Based On Online Social Networks, Adedamola Adesokan

Electrical and Computer Engineering ETDs

The prevalence of Online Social Networks has completely changed how individuals communicate and cooperate. This dissertation explores the integration of intelligent crowdsourcing mechanisms into OSNs, focusing on game theory, reinforcement learn- ing, and social network dynamics to enhance the allocation of tasks, participation by users, and distribution of rewards. It proposes several models that utilize trust- based models, hedonic coalition games, and influencer dynamics for optimization of crowdsourcing. The major challenges to be addressed include task selection, reward distribution, and incentivizing participation, taking into consideration aspects re- lated to social influence, trust, and user engagement. The models so proposed have …

Preclinical Development Of Genome Editing To Treat Duchenne Muscular Dystrophy By Exon Skipping, Made Harumi Padmaswari, Shilpi Agrawal, Christopher E. Nelson

Biomedical Engineering Faculty Publications and Presentations

Duchenne muscular dystrophy (DMD) is caused by loss-of-function mutations to the gene encoding dystrophin. Restoring the reading frame of dystrophin by removing internal out-of-frame exons may address symptoms of DMD. Therefore, the principle of exon skipping has been at the center stage in drug development for Duchenne muscular dystrophy (DMD) over the past two decades. Antisense oligonucleotides (AONs) have proven effective in modulating splicing sites for exon skipping, resulting in the FDA approval of several drugs using this technique in recent years. However, due to the temporary nature of AON, researchers are actively exploring genome editing as a potential long-term, …

Sensors And Sensibilities: Exploring Interactions For Habitat Comfort With An Environmental-Physiological Sensing Eyewear In The Wild, Sailin Zhong, Patrick Chwalek, Nathan Perry, David Ramsay, Clayton Miller, Denis Lalanne, S. Hamed Alavi, A. Joseph Paradiso

Research Collection College of Integrative Studies

Buildings increasingly incorporate sensing and actuation techniques to automate the regulation of temperature, lighting, ventilation, and more. This trend seeks to minimize human intervention, justified by the promise of enhancing energy optimization. However, it has been widely acknowledged that loss of control over environmental conditions can lead to a diminished perception of comfort and compromised long-term user awareness and satisfaction. How can we envision building systems that can interact with building inhabitants and engage them at the “right” time and place? In this work, we address this challenge through three key contributions: 1) AirSpecs, a novel smart glasses-based system that …

In Vitro Investigation Of Macrophage Functional And Metabolic Modulation, Shelby Nicole Bess

Graduate Theses and Dissertations

Macrophages are a subset of immune cells with a variety of functions that are abundant in numerous tumor types such as colorectal and breast cancer. It has been suggested that macrophages may serve an important function as immune mediators in tumor behavior; however, macrophage activity is complex and remains not completely understood. The overall goal of this dissertation was to explore and exploit tumor-associated macrophage phagocytic function and the changes in their interactions with cancer cells in an in vitro mouse model and in 2D and 3D in vitro culture models. First, we wanted to better understand macrophage behavior under …

Using Deep Learning And Two-Photon Excitation Fluorescence Microscopy To Predict Breast Cancer Recurrence And Response To Chemotherapy, Nicholas Powell

Graduate Theses and Dissertations

Accurate prediction of breast cancer recurrence plays a critical role in guiding treatment decisions, particularly regarding the use of systemic therapy for patients. While genomic assays such as the Oncotype DX Recurrence Score offer valuable prognostic information, they are limited in accessibility and application. The work presented in this thesis explores an imaging-based approach for the prediction of breast cancer recurrence that combines multiphoton microscopy (MPM) with deep learning to classify individual breast cancer biopsy samples by risk of recurrence. Genomic differences in tumors with different recurrence potentials may translate to distinct optical and structural information that can be captured …

Characterizing Heating And Resistance Properties Of Nichrome Burn Wire To Be Used In Cubesat Actuation, Noah Moix

Mechanical Engineering Undergraduate Honors Theses

This thesis investigates the use of Nichrome 60 wire as a burn wire mechanism, commonly utilized in CubeSats and other aerospace engineering applications requiring precise, single-use release systems. The experiment focused on characterizing the thermal and resistive behavior of Nichrome 60 wire under Joule heating conditions. Four wire configurations were tested: 34-gauge and 36-gauge wires, each at lengths of 1 inch and 2 inches. Each configuration was subjected to a constant current until thermal failure occurred. During testing, real-time measurements of electrical resistance and wire temperature were recorded. This data was used to generate resistance vs. temperature profiles for each …

Validating An Electronics Cooler Experiment And Optimizing Its Performance Using Ansys Icepak, Daniel V. Curl

Mechanical Engineering Undergraduate Honors Theses

Researchers at the University of Arkansas' Mechanical and Electrical Engineering Research Departments have designed and built a cold plate and substrate design for a 10 kV SiC MOSFET power module. Many variables define the design of the cold plate and substrate system and have quantifiable effects on the device’s performance. These variables include but are not limited to geometry and material selection of the fins and substrate. Manufacturing many test designs, running experiments, and comparing their performance is a time-consuming and expensive design optimization method that may be effective for some low-cost applications. Still, simulation is often a more cost-effective …

Thermal Characterization Of 3d Printing Materials For Increasing Insulation Potential And Practicality, Jackson H. Minnick

Mechanical Engineering Undergraduate Honors Theses

This study served as an exploration into the possible existence of a correlation between the infill lattice structure of a 3D printed wall section and the thermal performance of that sample as characterized by thermal conductivity measured in units of Watts per meter Kelvin. With the continual increase in the practicality, fidelity, and applicable fields of additive manufacturing, namely FDM 3D printing, research on specific print characteristics and their effects on the material and thermal characteristics of the part in question is steadily becoming more commonplace. Although the thermal conductivity of 3D printed wall sections as a function of infill …

Introduction To Building Energy Modeling And Analysis Using Energyplus, Jackson C. Burnett

Mechanical Engineering Undergraduate Honors Theses

Retail stores are dynamic environments where human activities significantly influence energy consumption patterns, particularly affecting heating, ventilation, and air conditioning (HVAC) demands. Existing energy models, such as those developed using EnergyPlus, often rely on generalized assumptions about human occupancy and behavior, leading to discrepancies between predicted and actual energy usage. This research aimed to enhance the accuracy of energy modeling for retail stores by conducting a sensitivity analysis of occupancy using EnergyPlus simulations. The study investigated how variations in occupancy levels impact HVAC loads, cooling and heating demands, and overall energy use. Results showed that increasing occupancy leads to higher …

Analog Low Dropout Regulator Design Within A 12nm Finfet Node, Harshdeep Singh

Graduate Theses and Dissertations

Modern ICs require the use of multiple voltage regulators to regulate power, this creates the need for analog low dropout regulator (LDO) designs in more advanced nodes such as for the 12nm FinFET process. Analog design is particularly challenging in FinFET processes due to a variety of factors, such as quantized parameters, large parasitic values and length of diffusion effects. An analog LDO was chosen for its improved power supply rejection ratio (PSRR) over digital and hybrid approach which is a key metric for voltage sensitive applications. The LDO was designed through an iterative approach to address the difficulty of …

Exploration Of Polymorphic Gate-Based Watermarking In Asynchronous Circuits, Stephanie Stock

Graduate Theses and Dissertations

With the increasing demand for new state-of-the-art integrated circuits (ICs), intellectual property (IP) reuse has become more commonplace to both accelerate the design process and lessen the non-recurring engineering costs of a design. Reuseable IP poses significant security risks, not only to the creator of the IP, but also to the consumer purchasing the IP. For an IP vendor, this risk can come from illegal distribution, cloning, or overuse. For the purchaser, counterfeit IPs may be purchased from an unvetted vendor, leading to a substandard design, malfunctions, IP infringement, or security vulnerabilities. Hardware watermarking is a method to protect designers …

Development Of Si-Based Germanium-Tin Infrared Photodiode, Sylvester Amoah

Graduate Theses and Dissertations

Short-wave infrared (SWIR) and mid-wave infrared (MWIR) photodetectors have attracted increasing attention for the past few decades. SWIR and MWIR detectors are used for a wide range of applications in military and civilian defense, such as future automotive night vision, video surveillance security cameras, and integrated night vision in mobile/wearable electronics. The current market-dominating IR photodetector technology is mainly developed with the costly III-V or II-V material systems, such as InGaAs, InSb, and HgCdTe. While many efforts have been made towards the hybrid integration of III-Vs or II-VIs on a Si substrate, it is highly desirable to develop an alternative …

Key-Based Authentication Scheme For Evtol Drones Using Chebyshev Chaotic Maps, Eduardo A. Hernandez Escobar

Master's Theses

The development of electric Vertical Take-Off and Landing (eVTOL) drones signifies a substantial advancement in urban air mobility, ready to transform transportation models in densely populated regions. These advanced drones, distinguished by their capacity to function in limited spaces and their minimized environmental impact, are set to transform individual, shipping, emergency services, and public safety activities. Nonetheless, like any transformational technology, the implementation of eVTOL systems presents many challenges, especially in the realm of cybersecurity. Adding many devices and entities to an eVTOL network increases the risk of privacy and security attacks. This paper proposes a key-based authentication scheme that …

The Histological And Mechanical Behavior Of Skin During Puncture For Different Impactor Sizes And Loading Rates, Joseph Lesueur, Jared Michael Koser, William Dzwierzynski, Brian D. Stemper, Carolyn E. Hampton, Michael Kleinberger, Frank A. Pintar

Biomedical Engineering Faculty Research and Publications

Purpose

The hierarchical structure of skin dictates its protective function against mechanical loading, which has been extensively studied through numerous experiments. Viscoelasticity and anisotropy have been defined for skin in tensile loading, but most puncture studies utilized skin simulants, which lacked natural tension and varying skin thicknesses. The purpose of this study was to define the mechanical behavior and failure thresholds of skin during puncture with various blunt impactor sizes and loading rates.

Methods

After determining natural tension of porcine skin, 232 isolated skin samples were loaded in puncture. Pre-conditioning, sub-failure, and failure trials were conducted with an electrohydraulic piston …

Investigation Of Control Strategies For Swing-Up Maneuver Of A Double Inverted Pendulum On Rotating Link, Abdulrahman Mohammad Rahmani

Thesis/ Dissertation Defenses

This thesis is concerned with investigation of the swing-up control problem of underactuated mechanical systems namely the double rotary inverted pendulum using the optimal control theory. The research aims to develop a robust controller to achieve the swing-up and stabilization of the pendulum in the upright unstable equilibrium position while regulating the angular displacement of the rotating arm and the two pendulum angles. The performance of the designed controller was evaluated through numerical simulations in the MATLAB/Simulink environment. A comprehensive review of the literature was conducted and the challenges that researchers face in the control of underactuated mechanical systems were …

Estimation Of Breach Hydrograph Resulting From Dam Embankment Failure Due To Internal Erosion Or Overtopping: Comparison Of Simplified Methods With Real-Case Failure Data And Recommendations, Laurent Del Gatto, Jean-Robert Courivaud

5th International Seminar on Dam Protections Against Overtopping

The opening of a breach in an embankment dam, whether due to overtopping or internal erosion, is a critical failure mode for these structures. Estimating the resulting breach hydrograph is essential for assessing downstream risks. While no universal physical model covers all dam types, empirical formulas are commonly used. EDF analyzed 14 such formulas, comparing them with rupture data from 32 embankment dam failures. The best formulas - Froehlich 1995, Xu & Zhang 2009, and CLF 2020 - yield a “best estimate” for peak flow. However, due to variability, results should be interpreted cautiously. Consider estimating breach characteristics like width …