Engineering Commons^™

Measuring The Effects Of The Leaves On Stalk Strength And Dynamic Response In Maize, Grant C. Ogilvie

Theses and Dissertations

Maize is one of the most widely cultivated grains in the world, making it crucial to world food security and important economically. One major problem in maize production is stalk lodging (greensnap), which results in billions of dollars in lost harvests annually for maize farmers in the US alone. Understanding the mechanical properties of maize plants is crucial to addressing this problem. Previous studies have suggested that the leaf blades and leaf sheaths affect maize mechanical properties. The objectives of this thesis are twofold: to present measurement techniques for the stalk bending strength, damping ratio, and natural frequency of maize …

A Novel Wrench Decomposition And Development Of A Large-Scale Soft Robot For Displacement-Based Human-Robot Collaborative Manipulation, Dallin Cordon

Theses and Dissertations

This work represents an examination of various facets of physical human-robot collaborative manipulation and the implementation of compliant, soft-robotic manipulators. A survey of physical human-human interaction and haptic communication is presented, alongside an investigation into the decomposition of force and torque components that enable effective human-robot collaboration. To address the inconsistent terminology found in previous literature, a standardized framework for force decomposition is proposed. A new taxonomy is introduced to categorize the force components involved in collaborative manipulation tasks. This taxonomy clarifies the role of each component in an agent's applied force during task execution and provides a structured framework …

Testing And Modeling Of Nonlinearities In Riveted And Bolted Structures, Joshua E. Blackham

Theses and Dissertations

Joints are difficult to model because of various small-scale and nonlinear features, such as local geometry, preload, friction and contact. These features cause a local change in stiffness and energy dissipation which result in changes in the effective natural frequency and damping of the whole structure. Past studies have found good success using nonlinear Iwan elements as whole joint models for bolted joints in a few different structures. In Chapter 3, a similar approach is proposed for modeling riveted joints, which seeks to capture the vibrational response of a test structure including changes in the effective modal frequency and damping …

Wind Collapse Risk And Serviceability Drift Of Steel Concentrically Braced Frame Buildings, Sarah Corrinne Partington Cluff

Theses and Dissertations

Seismic design provisions use the ductility and reserve strength of the lateral structural system to reduce the loads used in design, making the structural design more economical while maintaining life safety. In contrast, current wind design provisions do not. Conventional wind design relies primarily on elastic behavior. The objective of this study is to determine a wind response modification factor for steel concentrically braced frames that could be applied to reduce wind design loads based on ductility and reserve strength, while still meeting drift requirements for serviceability of the structure. To achieve the objective, three types of ductile braced frames …

Steps Towards Effective Human-Robot Co-Manipulation Through Real-Time Modus Detection And Effects Of Stiffness Variation For Human-Soft-Robot Dyads, Shaden Moss

Theses and Dissertations

A group of individuals can coordinate very easily to carry a large or heavy object together. This act of collaborative carrying is called co-manipulation. Unlike human teammates, robots cannot easily detect and respond to the intent of human partners during co-manipulation tasks. This shortcoming can be compensated for via the physical design and the software design of robots. This work treats software design with a neural net that detects human modus (or the manner in which a team moves an object together) in real time. This work treats physical design with the use of a soft robot in human-robot co-manipulation, …

Improving Devices To Measure The Thermal Conductivity Of Molten Halide Salts, Ryan J. Ruth

Theses and Dissertations

Molten salts are of high interest for use in nuclear reactors, though their thermophysical properties are notoriously hard to measure due to the extreme conditions created by them. Significant gaps remain in thermal conductivity and heat capacity data, which this work seeks to fill by improving the Needle Probe-a modified transient hot wire probe originally used by Merritt et al to measure the thermal conductivity of FLiNaK- measuring two new salts, and exploring new materials for use with molten salts. Improvements made to the Needle Probe include automation to reduce human error, more accurate heat generation modeling, a more thorough …

Strength And Ductility Of Rod-Braced Diaphragms In Metal Building Systems Subjected To Earthquake Ground Motions, James Niedens

Theses and Dissertations

Metal building systems are a common form of construction but the behavior of roof diaphragms in metal buildings that are subjected to earthquake ground motions is not entirely understood. In this study, the strength and ductility of rod-braced diaphragms with hillside washer connections or rod-pad connections was determined using experimental tests and computer simulation. Tensile tests of rods were used to determine the effect of the type of rod on strength and ductility. Two types of rods were tested, full-body rods with cut threads at each end of the rod and bracing rods with rolled threads. Three rod sizes (5/8 …

Navajo Speech Recognition Using Low-Resource Language Models, Emery M. Sutherland

Electrical and Computer Engineering ETDs

This thesis describes the development of a speech recognition system to classify Navajo (Dine) words using Low Resource Language (LRL) datasets. Presently there are no recognized high-quality open-sourced datasets for the Dine language needed to train models for speech recognition. A small balanced dataset was designed to train several models. To overcome the scarcity of the LRL dataset, the audio recordings were augmented to account for time-stretching, amplitude variations, time shifts, small amounts of white Gaussian noise, and SpecAugmentation. The models included a Recurrent Neural Network (RNN), a Convolutional Neural Network (CNN), and a Long Short-Term Memory (LSTM) model with …

Integrating Temperature-Dependent Tissue Properties Into Hifu Computational Models For Enhanced Treatment Planning, Christian Kevin Valencia Narva

Theses and Dissertations

Objective: High-intensity focused ultrasound (HIFU) is a non-invasive therapy that ablates diseased tissues with high precision. Computational simulations using the Pennes Bioheat Transfer Equation (PBTE) can guide HIFU treatment by predicting temperature distributions and thermal dose volumes. Traditional simulations assume constant thermal and acoustic properties, which may oversimplify tissue behavior. Methods: This study evaluates the impact of integrating temperature-dependent thermal properties (thermal conductivity, specific heat capacity, and perfusion) in finite-difference time-domain HIFU simulations. Three scenarios were simulated: (1) a homogeneous liver with both high- and low-power sonications, (2) a rabbit thigh muscle validated against preclinical MRTI data, and (3) an …

Eyes On The Road: Disentagling Cyclist Mental Workload At Intersections, James Joseph Rawson

Civil Engineering ETDs

In North America, cyclists often share infrastructure with motor vehicles and encounter frequent conflicts with them at intersections. While past research assumes cyclists' experiences mirror those of drivers, most studies focus on roadway segments rather than intersections. This study addresses that gap by, for the first time we are aware of, examining cyclist perceptions at intersections using head and gaze movement data. Leveraging naturalistic data conducted in Albuquerque New Mexico, and statistical techniques, including t-test and repeated measures ANOVA, our findings suggest that – similar to drivers - cyclists do experience greater mental workload when performing turning movements than when …

Development And Evaluation Of Canbench: A Testbed For Assessing The Security Of Automotive Can Buses, Trevor S. Mcclellan

Theses and Dissertations

Modern vehicles rely heavily on electronic control units (ECUs) that communicate via the controller area network (CAN) bus, a protocol developed in the 1980s with minimal security considerations. The growing number of ECUs has heightened the risk of cyberattacks on vehicles. Although CAN bus security has been extensively researched, the CAN standard still lacks built-in security measures. Furthermore, testing proposed security mechanisms is challenging due to the proprietary nature of automotive systems. To address this, an open-source physical testbed was developed using inexpensive, off-the-shelf components to support automotive CAN bus security research. The testbed provides a controlled environment for simulating …

Analysis Of Radial Inlet Distortion On Transonic Fan Performance, Tyler M. Reedy

Theses and Dissertations

Improving fan design and performance prediction requires an understanding of the impacts of inlet distortions. Inlet distortion describes any non-uniform distribution in the flow, usually referring to deviations in pressure and temperature. Using full annulus Unsteady Reynolds-Averaged Navier Stokes (URANS) simulations, the effects of both hub and tip radial distortions on the Air Force Research Lab (AFRL) Rotor 4 fan are analyzed. Overall performance, total pressure (Pt) distortion transfer, and total temperature (Tt) distortion generation are presented and compared for three operating points: near-stall, design, and choke. Hub radial inlet distortion magnitudes of 15% and 20%, and a tip radial …

Evaluating The Potential For Reusing Process Waste Fiber, Elisha Ewing

Honors Theses

This study was born out of curiosity around the potential use of reject materials from the papermaking screening system for molded fiber product development. The team sought to explore the technical feasibility of this concept and develop a proposed design for mill implementation. The project supports the common papermaking objective of reducing fiber loss from the stock preparation process.

The project assessed first the technical feasibility through laboratory testing and trials. The team dedicated time to characterizing screen reject samples from local mills and running trials using the good fibers extracted from the samples. Molded fiber products were successfully created …

Using Human Computation And Harmonic Expansions For Characterization And Design Of Grain Boundary Networks, Christopher W. Adair

Theses and Dissertations

Grain Boundary Networks (GBNs) are a high-dimensional feature in polycrystalline microstructural materials that are formed from the crystallographic degrees of freedom. This feature affects multiple material properties such as diffusivity, fracture, elasticity, heat transfer, and others. The link between the crystallography and the material properties is called the structure-property linkage, and allows for simulation and design of materials. While it is possible to use the structure-property linkage to design materials for better performance, the high-dimensional nature of the interconnected grain boundaries preclude the use of many common optimization algorithms for efficiency or local minima considerations. This work shows how the …

Boeing 747 Fixed Drive Link Redesign, Eric White

Honors Theses

This project focuses on redesigning the fixed drive link for the Boeing 747-400, a critical component of the flap actuation system that connects the drive mechanism to the flaps. Over recent years, this part has been prone to fracturing under full flap deflection. The Federal Aviation Administration (FAA) and Boeing have investigated this issue but have not successfully developed a durable solution.

This problem was presented by Kalitta Air, an air freight company experiencing frequent failures and costly maintenance related to the fixed drive link. If fracturing of the fixed drive link occurs the component must immediately be replaced. Similar …

Design Of A Retaining Wall For M-10 Freeway, Anthony Paul

Honors Theses

The M-10 Freeway, also known as the John C. Lodge Freeway, is bordered by retaining walls at the project location, one section of which required replacement to meet safety and serviceability standards. Located in Detroit, Michigan, this project focused on the redesign and replacement of a 300-foot section of retaining wall along the southeast-bound lanes of M-10, between Curtis Street and Outer Drive. The 20-foot-tall retaining wall also supports traffic loads from the overhead James Couzens Freeway. Through geotechnical and structural design, several alternatives were developed and evaluated. A CIP concrete cantilever wall was selected with a height of 21 …

Variable Volume Refrigerator, Ryder Dietz

Honors Theses

This project presents the design and development of a Variable Volume Mini-Fridge Shelf, a solution to address the limitations of fixed compartment sizes in standard mini-fridge/freezer units. The proposed design enables users to dynamically adjust the internal ratio of fridge to freezer space using a repositionable shelf integrated with an airflow-regulating vent. The project involved multiple stages, including concept development, thermal and flow simulations, and physical prototyping.

SolidWorks Flow Simulation was employed to validate natural convection-driven airflow between compartments and guide initial design decisions. While attempts were made to integrate a dynamic control loop using MATLAB Simulink and the SolidWorks …

Rf Emission From Partial Breakdown Events And Their Classification, Torin Sammeth

Electrical and Computer Engineering ETDs

Electrical breakdown is a core component of Pulse Power both in its utilization and as a failure point in systems. This research is investigating the feasibility of D-dot antennas to detect and potentially identify different forms of partial electrical breakdown in a point-to-plane gap geometry. In this work, the RF emission detected by a D-dot probe during a partial breakdown event is shown to correlate with the presence of light and current using a fast-current transformer and photomultiplier tube. Additionally, the frequency components of the RF signal were measured with the use of a fast Fourier transform. Identifying these frequencies …

Nanostructured Transition Metal Oxides For Electrochemical Co2 And Methane Conversion, Olumide O. Oladoyin

Chemical and Biological Engineering ETDs

Rising atmospheric CO₂ and CH₄ drive climate change, prompting research into their electrochemical conversion to valuable products. This study investigates electrodeposited nanostructured transition metal oxides (TMOs), unary (CuO, Co₃O₄) and dual (Cu-Co oxide) as catalysts for CO₂ reduction and CH₄ oxidation under ambient conditions. Fabricated on various substrates (Cu foil, SS316, carbon paper) and characterized by SEM, their electrochemical performance was evaluated via cyclic voltammetry.

Cu-Co oxide showed superior CO₂ reduction, leveraging the strengths of individual oxides. Co₃O₄ exhibited higher current densities for CH₄ oxidation, with SS316 proving the best substrate. Catalyst composition, morphology, and substrate significantly influenced efficiency. While …

A Dynamically Efficient Predictive Controller For Voltage Stability In A Dc To Dc Boost Converter, Giovanni Reyna

Electrical and Computer Engineering ETDs

Reliable voltage regulation has become a critical issue with increase demand in modern power electronic applications. This study presents a Model Predictive Controller (MPC) for voltage regulation in DC-to-DC boost converters. A closed loop analytical MPC framework is created with the purpose of computing optimal duty cycles to maintain a stable output voltage under varying load conditions, input changes, and disturbances.

To evaluate the performance of the MPC we set the controller against a comparative analyzing with a traditional cascading proportional integral (PI) controller. The proposed controller design is specifically targeted to improve dynamic efficiency during the converter’s transient events. …

An Analysis Of The Encryption Algorithms Proposed For The Mqtt Protocol On Resource Constrained Iot Devices, John Joseph Keenan

Theses and Dissertations

As more IoT devices are used to gather data and automate devices throughout the world, more security solutions are needed to keep these devices and the data they transmit secure. Many of these devices use the MQTT protocol, which does not encrypt the transferred data by default. The TLS/SSL protocols are the standard proposed solution for encrypting this traffic, but many resource constrained IoT devices do not have enough resources to run these protocols efficiently. Because of this, many other encryption algorithms have been proposed or designed for resource constrained IoT devices running the MQTT protocol, but very limited research …

The Development Of Electroanalytical Methods For Molten Salt Mixtures Under Static And Flowing Conditions, Ranon Fuller

Theses and Dissertations

Electroanalytical methods have the potential to characterize molten salt systems in situ, determine physical properties such as diffusion coefficients and standard potentials, and measure kinetic and corrosion rates. Due to experimental difficulties of working with molten salts including high temperatures and high natural convection, transport, kinetic, and corrosion rates, many precise, consistent methods have yet to be established. In this work, we describe methods to precisely calculate standard reduction potentials, characterize molten salt solutions containing multiple lanthanides by reduction potentials and metal deposition mechanisms, calculate the number of electrons exchanged in metal deposition using SWV, calculate diffusion coefficients using CV, …

Antenna Analysis Using Mixed Computer Platforms (Aacp), Keith H. Bova

Electrical and Computer Engineering ETDs

This thesis reviews the design, implementation, and benchmarking of commercially available, previous generation (CAPG) computer systems, and how they can be used with computational electromagnetics. The thesis focuses on their architecture, performance, and practical applications. It begins with an overview of CAPG system components, including different node types such as login/controllers, compute nodes, block storage, and object storage. The process of assembling these systems is outlined. The conjugate gradient method and direct linear solvers were benchmarked. The performance of CAPG systems is compared with modern computing architectures. A detailed analysis provides recommendations for designing CAPG systems around the performance of …

Aerosol Technology For Carbon Capture And Utilization, Onochie Chinedum Okonkwo

McKelvey School of Engineering Graduate Student Theses & Dissertations

The CO2 concentration in the atmosphere has continued to increase over the past century and now poses an increasing potentially catastrophic effect to human life and the environment via global warming and the concomitant effect of climate change. Anthropogenic carbon dioxide emissions due to fossil fuel combustion for increasing energy demand is the main driver for the increased carbon dioxide in the atmosphere. A multifaceted approach including carbon dioxide capture and utilization is required to mitigate anthropogenic carbon dioxide emissions. Aerosol science and technology, an enabler for clean combustion technologies and nanomaterial synthesis, can contribute significantly to the advancement of …

Electric Field Profiles Under High Voltage Overhead Transmission Lines With Under-Build Distribution Circuit, Aminu Haruna

Electrical Engineering Theses

The increasing use of underbuilt lines in recent transmission projects alters electric field profile under transmission lines. By assessing electric field intensity in these transmission and distribution network configurations, the study identifies regions with high electric fields that may exceed standard exposure limits, posing potential risks. This work employs the charge simulation method and the method of imaging to analyze electric fields beneath transmission lines with underbuilt distribution networks. Key objectives include calculating the electric fields at 1 meter above ground, and evaluating the field at conductor surfaces. The study considers transmission line voltages of 69kV, 161kV, 220kV, 345kV and …

Cyber Physical Emulation Of Power Grids: Co-Simulation Of Exata Cps And Hypersim, Mckayla Snow

Electrical and Computer Engineering ETDs

This thesis explores the use of cyber-physical emulation of power grids to analyze the impact of different types of cyberattacks. It outlines the co-simulation process of HYPERSIM and EXata CPS within the OPAL-RT real-time digital simulator, demonstrating various cyberattacks on two power system models. The first model is a simple communication-focused testbed for easy demonstration of co-simulation setup, while the second is a power system model of a secondary network used to assess the cybersecurity of network protector units in low-voltage networks through a hardware-in-the-loop (HIL) testbed. Using this testbed, the cybersecurity of the direct transfer trip (DTT) scheme is …

Metabolite Analysis To Understand Factors Limiting Microbial Fermentation At High Substrate Concentrations, Bishal D. Sharma

Dartmouth College Ph.D Dissertations

Clostridium thermocellum, a thermophilic anaerobic bacterium, holds promise as a biocatalyst for conversion of lignocellulosic biomass into biofuels. This microbe has been subjected to various metabolic engineering strategies, including the deletion of genes encoding secondary fermentation products such as H₂, formate, acetate, and lactate, as well as the expression of heterologous genes to redirect carbon flux toward ethanol production. Despite these efforts, achieving economically viable ethanol titers remains a challenge. We hypothesized that studying how intracellular metabolite concentrations change as fermentation stops could reveal metabolic bottlenecks or regulatory mechanisms limiting ethanol production at high titers. However, metabolomics studies at …

From Adversarial Attacks To Robust Classifiers - A Study In Social Media Spam Detection - Black Box & White Box, Jonathan Jose Penaloza Rumie

Undergraduate Theses

Adversarial attacks pose a significant threat to the reliability of machine learning-based spam detection systems in social media. This undergraduate thesis, "From Adversarial Attacks to Robust Classifiers: A Study in Social Media Spam Detection – Black Box & White Box," systematically examines the impact of both black-box and white-box adversarial attacks on a range of spam classifiers, including Logistic Regression, Decision Trees, Random Forests, K-Nearest Neighbors, Bagging, Gradient Boosting, and Support Vector Machines. Leveraging a novel dataset derived from Twitter spam messages and enhanced with adversarial perturbations such as synonym replacement and character-level modifications, this study evaluates classifier performance under …

Reconstruction From Variable Aperture Measurements Using Band-Limited Inversion Algorithms, Harrison C. Garrett

Theses and Dissertations

The signal reconstruction process from discrete samples is inherently band-limited due to the limited amount of spectral content in the discrete set of measurements. In the case of 1D sampling using ideal measurements, the maximum bandwidth of regular and irregular sampling is well known using Nyquist and Gröchenig sampling theorems and lemmas, respectively. However, determining the appropriate reconstruction bandwidth becomes difficult when considering 2D sampling geometries, samples with variable apertures, or signal to noise ratio limitations. Instead of determining the maximum bandwidth a priori, this thesis introduces the use of a bandlimited inverse to simultaneously reconstruct a signal and determine …

The Impact Of Visual Stimuli And The Properties Of Green Walls On Human Well-Being In Built And Immersive Virtual Environments, Alireza Sedghikhanshir

LSU Doctoral Dissertations

The built environment significantly influences human well-being, particularly in the context of stress recovery and cognitive restoration. This dissertation investigates the impact of visual stimuli, particularly green walls, on human responses related to stress, restoration, and thermal comfort. The research is guided by three primary objectives: (1) examining the role of visual stimuli and their properties in promoting stress recovery and restoration, (2) evaluating the potential of Immersive Virtual Environments (IVEs) as tools for delivering and studying restorative environments, and (3) investigating the influence of green walls on indoor environmental conditions.

A series of experimental studies were carried out to …