Other Mechanical Engineering Commons^™

Adaptation Of A Commercially Available Galvanic Skin Response Sensor To Measure Respiration Across The Chest For Heart Rate Variability Monitoring, Breno C. Dobal

Honors Undergraduate Theses

Heart rate variability (HRV) is a naturally occurring cardiovascular phenomenon referring to the changing timing between consecutive heartbeats. The connection between HRV and overall cardiovascular health and autonomic nervous system function has been well established through prior research and well documented in existing literature. The existing studies, however, included shorter HRV subject recording session, using traditional HRV monitoring methods that do not typically combine electrocardiogram (ECG), seismocardiogram (SCG) and galvanic skin response (GSR) respiration monitoring. The inclusion of longer HRV subject recording may allow for further insight on the possible effects of given observable biological phenomenon on HRV.

The current …

Self-Supervised Contrastive Learning Using Eeg Signals For Mental Stress Assessment, Ugochukwu Uraechu

College of Graduate Studies: Theses & Dissertations

A study is presented to investigate self-supervised contrastive learning (SSCL) models using physiological data obtained from non-invasive wearable sensors for mental stress assessment. The present work involved acquisition of electroencephalography (EEG) signals using wearable sensors, signal preprocessing, data augmentation, and investigation of self-supervised contrastive learning (SSCL) algorithms for multi-class mental stress assessment. Seven volunteers participated in this study executing various mental tasks while wearing an OpenBCI head cap to acquire EEG signals. The acquired EEG signals were preprocessed and utilized for data augmentation in time and frequency domains with different SSCL models. Optimal data augmentation combinations and SSCL models were …

Mathematical Modeling Of Coupled Heat And Mass Transfer In Metal-Hydride Hydrogen Storage Systems, Muhammad Hasnain

College of Graduate Studies: Theses & Dissertations

As a promising clean energy carrier hydrogen has recently gained significant interest, but its efficient and safe storage is a major challenge. Compared to the gaseous state and liquid state, metal hydrides (MH) offer a potentially more effective storage approach for hydrogen. However, the main challenge in this approach is the low thermal conductivity of the MH bed that leads to low heat transfer and ultimately to higher charging and discharging times. The purpose of this work is to develop an in-house comprehensive heat and mass transfer model for hydrogen sorption in MH reactors to simulate the dynamic behavior of …

Understanding The Impacts Of Extreme Weather On The Power Transmission Infrastructure: A Machine Learning Approach To Quantifying Risks And Enhancing Grid Resilience, Juan P. Montoya Rincon

Dissertations and Theses

This doctoral dissertation focuses on the resilience of power transmission infrastructure in tropical coastal environments, particularly in the face of extreme weather events such as hurricanes. The research is anchored on the case of the passage of Hurricane Maria in the Island of Puerto Rico in September of 2017 which caused the largest damage on the power infrastructure in US history. As such, the research investigates the interaction between extreme winds and power transmission infrastructure in complex terrain, aiming to quantify and predict power loss and damage to the infrastructure during such events. The study employs a comprehensive approach combining …

Numerical Modeling Of Thermal Runaway In Lithium-Ion Batteries Using Decomposition Kinetics And Inter-Cell Contact Resistance, Shehzad Khan

College of Graduate Studies: Theses & Dissertations

Lithium-ion batteries (LIBs) are central in numerous high-demand applications due to their high energy density and prolonged cycle life. Despite these advantages, their susceptibility to thermal runaway (TR) poses a significant safety risk, with the potential for catastrophic failures. This study focuses on the thermal behavior of prismatic lithium-ion cells, using a finite volume-based partial differential equation (PDE) solver developed in MATLAB and JULIA to model TR behavior. This solver accurately simulates transient behaviors, convection, diffusion, and source terms across various coordinate systems. By engaging in a series of increasing complex case studies, this research aims to identify the critical …

Comprehensive Review And Development Of A High-Pressure Hydraulic Impedance Tube For Vibroacoustic Attenuator Characterization, Matthew D. Beals

Dissertations, Master's Theses and Master's Reports

This research establishes a versatile test bench for characterizing hydraulic vibroacoustic attenuators. The primary evaluation metric is the transfer matrix, determined experimentally, with an emphasis on key properties such as transmission loss. To ensure accuracy and broad applicability, the methodology is based on industry-standard techniques for determining the transfer matrix. A comprehensive literature review consolidates existing approaches for hydraulic attenuator characterization. The test bench features a hydraulic impedance tube equipped with eight dynamic pressure transducer (DPT) taps strategically positioned before and after the sample interface. This setup accommodates arbitrary samples terminated with standard hydraulic fittings. Using ASTM E2611, the transfer …

Energy Efficient Spintronic Devices For Non-Volatile Memory And Hardware Ai, Walid Al Misba

Theses and Dissertations

Nanomagnetic devices have emerged as a promising alternative to conventional complementary metal-oxide-semiconductor (CMOS) devices due to their low energy dissipation and inherent non-volatility. However, the widespread adoption of these devices requires high-density, high-speed, reliable, scalable, and energy-efficient technologies. This thesis investigates the use of nanomagnetic memory devices as both conventional Boolean memory and multistate memory for hardware AI applications.

Magnetic tunnel junctions (MTJs) are nanomagnetic memory devices that can be switched reliably and energy-efficiently using stress-mediated switching. However, realistic material inhomogeneity and scalability pose challenges for stress-mediated switching of MTJs scaled to lateral dimensions below 50 nm. We demonstrate that …

Integration Of Infrared Thermography And Deep Learning For Real-Time In-Situ Defect Detection And Rapid Elimination Of Defect Propagation In Material Extrusion, Asef Ishraq Sadaf

College of Graduate Studies: Theses & Dissertations

This study presents a novel approach to overcoming process reliability challenges in Material Extrusion (ME), a prominent additive manufacturing (AM) technique. Despite ME's advantages in cost, versatility, and rapid prototyping, it faces significant barriers to commercial-scale production, primarily due to quality issues such as overextrusion and underextrusion, which compromise final part performance. Traditional manual monitoring methods severely lack the capability to efficiently detect these defects and highlight the necessity for an efficient and real-time monitoring solution. Considering these challenges, an innovative and field-deployable infrared thermography-based in-situ real-time defect detection and feedback control system is proposed in this thesis. A novel …

Understanding The Impact Of Process Interruption On Mechanical Properties In Metal Additive Manufacturing: A Comprehensive Investigation, Poojith C. Chigurupati

College of Graduate Studies: Theses & Dissertations

Metal additive manufacturing techniques enable rapid prototyping and on-demand manufacturing while improving supply chain resiliency. Changes in microstructure and micro-mechanical characteristics of 3D printed metal parts occur due to the influence of process interruptions on melting-solidification cycles during the layer evolution in additive manufacturing processes. The process interruption can deteriorate the structural integrity of the 3D printed parts and generate micro-flaws in the interruption region. Manufacturing post-processing techniques such as Heat-Treatment methods can enhance the mechanical properties of the parts. Since variations commonly happen at the layer level, the investigation of mechanical properties must be done such that these variations …

An Investigation Of The Performance Of A 140 Kw Solar Panel In West Virginia, Rumana Subnom

Graduate Theses, Dissertations, and Problem Reports (ETD)

Solar panels are recognized as a viable technology for producing electricity from sunlight. The performance of a solar panel is influenced by factors such as solar irradiance, tilt angle, orientation, shading, panel age, degradation, and various environmental conditions including ambient air temperature, humidity, dust, soil, and snow.

In this research, a mobile solar panel testing system consisting of a mobile cart, a solar panel, and a portable power station was designed and fabricated to evaluate the performance of a solar panel. The battery is equipped with a thermal management system controlling its temperature and charging and discharging system. The current …