Engineering Commons^™

An Investigation Of The Relationship Between Respiration And Seismocardiographic Signals Using Signal Processing, Machine Learning And Finite Element Analysis, Tanvir Hassan

Electronic Theses and Dissertations, 2020-2023

Cardiovascular disease (CVD) is one of the major causes of death worldwide. Disease management, as well as patient health, can be significantly improved by early detection of patient deterioration and proper intervention. Review of the patient's medical history and physical examination including stethoscope auscultation and electrocardiograms (ECG), echocardiography imaging, numerous blood testing, and computed tomography are common means of evaluating cardiac function. Seismocardiographic (SCG) signals are the vibrations of the chest wall due to the mechanical activity of the heart. These signals can provide useful information about heart function and could be used to diagnose cardiac problems. The variability in …

Exploration Of Warm-Up Protocols On Muscular Fatigue, Sahil Kapadia

Honors Undergraduate Theses

Muscular dystrophy is a genetically linked myopathy with no cure available. The lack of a cure makes early detection and treatment of muscular dystrophy imperative. When reviewing protocols examining muscular fatigue at submaximal isometric contractions, proper warm-up appeared to be absent and could have caused skewed results and conclusions. This study examines the effects of implementing a warm-up protocol before fatiguing trials. In this study, 10 adult subjects conducted fatiguing protocols with the right rectus at submaximal isometric contractions. The warm-up period included a light walk along with contractions at 20% and 33% of maximal voluntary isometric contraction (MVIC) levels. …

Probing The Effect Of Hyperglycemia On Endothelial Force Generation And Transmission, Jovani J. Gutierrez

Honors Undergraduate Theses

This thesis intends to utilize biomechanics to study the endothelial biomechanical response in a static hyperglycemic microenvironment. Hyperglycemia is a diabetic condition with abnormally high levels of glucose in the bloodstream. The effects of hyperglycemia over time lead to vascular complications resulting in patients being more prone to cardiovascular diseases. Current studies have focused on the molecular mechanisms affected by hyperglycemia; however, the mechanical mechanisms by which hyperglycemia causes vascular structural and functional changes are understudied. Therefore, to study the effects of hyperglycemia in the endothelium, Human Umbilical Vein Endothelial Cells (HUVEC) were cultured under three glucose conditions: normal glucose …

An Investigative Design Of Gas Jet Nozzles And Their Flow Field Effect On Spatial Distribution, Adam Phengsomphone

Honors Undergraduate Theses

Within this study, the presented material has the objective of providing insight and design characteristics for gas jet nozzles that experimentalists and researchers should consider when utilizing this experimental method. Firstly, this study introduces the developing history and necessity for gas jet experiments and its well-known drawbacks, eventually leading to recent studies and founded knowledge regarding the nozzle geometry dependence on the flow field. The simulation methodology of this study will be presented where the discretization of the computational domain, selection of the flow physics model, and overall design of the nozzle geometry is explained and justified. The flow field …

An Introduction To The Comparison Of Seismocardiography And Phonocardiography, Anna C. Voyatzoglou

Honors Undergraduate Theses

The intent of this thesis is to lay groundwork for examining the relationship between seismocardiography (SCG) and phonocardiography (PCG). Both are methods of measuring and describing heart mechanical function. SCG is described as chest vibrations while the heart beats, and PCG is described as acoustic chest surface signal believed to represent the heart valves opening or closing. SCG and PCG have both been used separately in clinical and research settings, but there is currently no clear comparison between the two. Therefore, there has been no way at the present to understand how one signal might inform the other. This study …

Design And Development Of Medical Devices For Multifaceted Applications, Madisyn Messmore

Honors Undergraduate Theses

The fields of biotechnology and biomedical sciences are rapidly evolving and involve the constant growth of knowledge. As a consequence, engineering design has to also remain at the cutting edge in order to not inhibit the growth of these fields. This study focuses on engineering design and analysis as it pertains to the field of biotechnology, at every step of the engineering process. More specifically, how the engineering design and analysis approach can assist in solving medical problems relating to bone diseases and biomaterials. The first part of the study focuses on a project to design and manufacture a novel …

Thermofluidic Characterization Of Carbon Dioxide Near Critical Conditions At Microscale, Anatoly Parahovnik

Electronic Theses and Dissertations, 2020-2023

This work revealed the thermo physical characteristics of near critical and supercritical carbon dioxide at the micro scale. The results include the extension of flow boiling heat transfer correlations, boiling inception, near critical bubble dynamics, thermalization mode shift, Joule Thomson effect and pressure drop evaluation. It was found that extremely low superheat temperatures are required for boiling inception near the critical conditions (i.e., T=31.4 °C, and P=7.37 MPa), and boiling heat transfer correlations were extended up to a reduced pressure of 0.99. The work also revealed a significant enhancement of the heat transfer coefficient as the critical conditions approached, which …

Data-Driven Modeling Of Mechanical Behaviors Of Additively Manufactured Materials, Ziyang Zhang

Electronic Theses and Dissertations, 2020-2023

Additive manufacturing (AM) is a revolutionary technology that greatly improves the flexibility of fabricating parts with complex structures and eliminates the cost of making molds. While AM techniques offer unique benefits over traditional manufacturing processes, it is challenging to predict the mechanical behaviors of additively manufactured parts based on design and process parameters. With recent advances in machine learning, data-driven methods have the potential to overcome such limitations. In this work, data-driven modeling frameworks were proposed to predict the tensile, flexural, and compressive behaviors of additively manufactured plastics and composites. Ensemble learning was used to predict the tensile strength of …

Vibrations Of Rotationally Periodic Structures: A Metric For Mistuning Characterization And Vibration Localization, Andres Rodriguez

Electronic Theses and Dissertations, 2020-2023

Blisk components are an integral part of jet engines and power generation systems. Composed of a single monolithic structure, integral blisks combine the blade-and-disk portion of primary components such as the fan, compressor stage, or turbine stage. This design modification increases the aerodynamic performance while decreasing the cost and eliminating time of assembly. However, these benefits come with the loss of blade-disk connection interfaces, which greatly reduces the structure's damping and its ability to attenuate unwanted structural vibrations. Blisk dynamics are impacted by mistuning, which is a disruption of the periodic symmetry of otherwise identical bladed sections. This disruption degrades …

Mean Pressure Gradient Effects On Flame-Flow Dynamics In A Cavity Combustor, David M. Smerina

Honors Undergraduate Theses

Pressure gradient confinement effects are experimentally investigated within a cavity combustor to analyze the flame interactions of premixed, cavity stabilized, flames in a high-speed combustor. Pressure gradient confinement effects are generated in a dual mode ramjet-scramjet (DMSR) by varying the wall geometry to form converging, diverging, and nominal configurations. The velocity field and flame position are captured temporally using simultaneous high-speed particle image velocimetry (PIV) and CH chemiluminescence. The evolution of the flow field and flame structure are analyzed, and the high temporal resolution of these measurements allows for the characterization of turbulence-flame interactions. Consideration of the combustion mode and …

Effect Of The Extended Rigid Flapping Trailing Edge Fringe On An S833 Airfoil, Hongtao Yu, Zifeng Yang

Mechanical and Materials Engineering Faculty Publications

A 2D numerical simulation was conducted to investigate the effect of an extended rigid trailing edge fringe with a flapping motion on the S833 airfoil and its wake flow field, as an analogy of an owl’s wing. This study aims to characterize the influence of the extended flapping fringe on the aerodynamic performance and the wake flow characteristics downstream of the airfoil. The length (Le) and flapping frequencies (fe) of the fringe are the key parameters that dominate the impact on the airfoil and the flow field, given that the oscillation angular amplitude is fixed at 5◦. The simulation results …

Demonstration Of High-Temperature Operation Of Beta-Gallium Oxide (Β-Ga2o3) Metal-Oxide-Semiconductor Field Effect Transistors (Mosfet) With Electrostatic Model In Comsol, Nicholas Paul Sepelak

Browse all Theses and Dissertations

β-Ga2O3 is a robust semiconductor material set with a large band gap of ~4.8 eV, low intrinsic carrier concentration, and high melting point that offers a stable platform for operating electronic devices at high temperatures and extreme environments. The first half of this thesis will cover the fabrication of a fixture and packaging to test electronic components at high temperatures. Then it will highlight the characterization of β-Ga2O3 field effect transistors from room temperature (RT) up to 500 °C. The devices, fabricated with Ni/Au and Al2O3 gate metal-oxide-semiconductor (MOS), demonstrate stable operation up to 500 oC. The tested device shows …

Design And Testing Of A Hybrid Direct Ink Writing And Fused Deposition Modeling Multi-Process 3d Printer, Alexander X. Losada

Honors Undergraduate Theses

Multi-material 3D Printing allows the ability to fabricate parts with tuned mechanical properties, multi-process 3D printing widens the choices of available fabrication materials. The objective of this study is to build a custom 3D printing test bed that is capable of printing multi-material parts with fused deposition modeling and direct ink writing techniques. A 3D printer, controlled by an industrial motion control system, with FDM and DIW capabilities was built by combining FDM extruders with a pneumatic dispensing system on a single platform. By utilizing the Direct Ink Writing function, we expand the number of printable materials to include some …

Quantitative Metallurgy Of Anisotropic Nickel-Base Superalloys Under Tensile And Fatigue Loading, Dominic Devito

Electronic Theses and Dissertations, 2020-2023

Nickel-base superalloys are ideal materials for application in high temperature and high stress environments. Their resistance to both heat and corrosion makes these metals well-suited for use as components in engines and turbines. There has been much interest in characterizing the mechanical properties of Ni-base superalloys under severe conditions. Either large monotonic loads or cyclic loads are the most investigated. Also, research efforts tend to focus on the influence of microstructural features of fatigue life, and they accomplish this through qualitative observation. Presented here is both quantitative and qualitative analysis done on Ni-base superalloy specimens that have been subjected to …

Synthesis, Characterization, And Modeling Of Thermo-Responsive Hydrogels With Improved Mechanical Strength And Swelling Kinetics, Marilu Ortiz Nieves

Electronic Theses and Dissertations, 2020-2023

Hydrogels have been extensively studied for use in applications such as tissue engineering, drug delivery systems, wound dressing, actuators, valves, and sensors in Micromechanical Systems (MEMS), among others. Thermo-responsive hydrogels in particular pose various advantages such as their capability to respond to an external stimulus and reverse the response when the stimulus is removed and the ability to imbibe a significant amount of solvent and increase their volume by over 1000%. Extensive research has been conducted to tune and improve hydrogel’s rate and degree of swelling and mechanical properties. Previous work showed that when synthetic clay (Laponite) is cross-linked with …

Closed Loop Recycling Of Low Friction Polymers In Fused Granule Fabrication Additive Manufacturing Processes, Neil Thompson, Jason Weaver

Faculty Publications

Plastic waste is a critical worldwide problem that impacts additive manufacturing (AM). Extensive research has explored how plastic waste in AM can be reduced by recycling prints into new filament, with varying success. An alternative to filament-based extrusion is “fused granule fabrication” (FGF), which extrudes from pellets or granules. This method is often used for large area additive manufacturing (LAAM) of polymers. This paper expands upon the knowledge base from previous research on LAAM and examines the extent to which PETG can be recycled and reprinted through the same FGF tool without significant loss to its material properties. The metric …

Durability Of Vacuum Infusion Tooling Produced From Fused Granular Fabrication Additive Manufacturing, Nathan Northrup, Jason Weaver, Andy R. George

Faculty Publications

Large area additive manufacturing (LAAM) has the capability to create tooling that is lower cost than conventionally manufactured tooling and still has sufficient properties for many applications. A vacuum infusion mold was printed from fiberglass-ABS and evaluated for wear and suitability for small vacuum infusion runs. The mold was designed to accentuate high wear as a “worst case” scenario. The mold was able to produce 10 parts successfully before any noticeable change occurred to the surface finish. By 14 parts, the surface finish had roughened sufficiently that demolding was difficult and resulted in damage to the part. Profilometry measurements showed …

Crystal Viscoplastic Modeling Of Single Crystal And Directionally Solidified Nickel-Base Superalloys, Navindra Wijeyeratne

Electronic Theses and Dissertations, 2020-2023

Nickel-base superalloys (NBSAs) are widely used in engineering applications for many turbomachinery component designs. Superior material properties at high temperatures such as high tensile strength, superior fatigue strength, excellent resistance to thermal shocks, and strong corrosion resistance are primarily responsible for their extensive application. This proposal focuses on modeling generic single crystal (SX) and directionally solidified (DS) Ni-base superalloy. Compared to polycrystal superalloys, SX superalloys exhibit superior thermal fatigue and creep resistance which is attributed to the absence of grain boundaries in the SX crystalline structure. Directional solidification procedures enable the solidification structure of the materials to be comprised of …

Lithium-Ion Battery Prognosis With Variational Hybrid Physics-Informed Neural Networks, Renato Giorgiani Do Nascimento

Electronic Theses and Dissertations, 2020-2023

Lithium-ion batteries are an increasingly popular source of power for many electric applications. Applications range from electric cars, driven by thousands of people every day, to existing and future air vehicles, such as unmanned aircraft vehicles (UAVs) and urban air mobility (UAM) drones. Therefore, robust modeling approaches are essential to ensure high reliability levels by monitoring battery state-of-charge (SOC) and forecasting the remaining useful life (RUL). Building principled-based models is challenging due to the complex electrochemistry that governs battery operation, which would entail computationally expensive models not suited for prognosis and health management applications. Alternatively, reduced-order models can be used …

Heat Transfer Characterization Of Carbon Dioxide In Micro Impinging Jet(S) Near Critical Conditions, Stephen Adeoye

Electronic Theses and Dissertations, 2020-2023

The continuous growth and demand of increased operating performances of electronics has brought about an increase in the chip power density posing threat to the thermal management of these devices. Although numerous thermal solutions ranging from passive to active cooling together with a variety of working fluids have been adopted, however, the question whether these available cooling methods could meet up with the ever-growing need for increased operating performances is a concerning one. Jet impingement cooling has been effectively used in many industrial applications due to its high heat transfer capability. The limited study at the micro scale suggests that …

Numerical Study Of Flow Of Supercritical Carbon Dioxide Inside Microchannels With Heat Transfer, Uday Manda

Electronic Theses and Dissertations, 2020-2023

Heat transfer inside microscale geometries is a complex and a challenging phenomenon. As supercritical fluids display large variations in their properties in the vicinity of the critical point, their usage could be more beneficial than traditional coolants. This numerical study, in two parts, primarily focuses on the physics that drives the enhanced heat transfer characteristics of carbon dioxide (CO2) near its critical state and in its supercritical state. In the first part of the study, the flow of supercritical Carbon Dioxide (sCO2) over a heated surface inside a microchannel of hydraulic diameter 0.3 mm was studied using three-dimensional computational fluid …

Decentralized Digital Fabrication Of Flexible Micro/Nano Devices Using A Laserjet Printer, Arshya Bamshad

Electronic Theses and Dissertations, 2020-2023

The fabrication of traditional micro/nano devices requires access to cleanrooms, complex and expensive tools, and highly-skilled labor. A facile and digital do-it-yourself (DIY) technique for the fabrication of low-cost devices on flexible substrates (paper, cloth, and plastic films) is presented in this work. A set of office-grade equipment (i.e., laserjet printer, thermal laminator, computer-aided paper cutter), and commercially available supplies (i.e., baking wax paper, furniture restoration metal-leaf) are utilized. The presented technology enables community-embedded production by removing a high technological barrier. The validity of the proposed technology was proved by designing three levels of experiments, i.e., patterns, devices, and systems. …

Recent Advances In Biosensors For Detection Of Covid-19 And Other Viruses, Shobhit K. Patel, Jaymit Surve, Juveriya Parmar, Kawsar Ahmed, Francis M. Bui, Fahad Ahmed Al-Zahrani

Department of Mechanical and Materials Engineering: Faculty Publications

This century has introduced very deadly, dangerous, and infectious diseases to humankind such as the influenza virus, Ebola virus, Zika virus, and the most infectious SARS-CoV-2 commonly known as COVID-19 and have caused epidemics and pandemics across the globe. For some of these diseases, proper medications, and vaccinations are missing and the early detection of these viruses will be critical to saving the patients. And even the vaccines are available for COVID-19, the new variants of COVID-19 such as Delta, and Omicron are spreading at large. The available virus detection techniques take a long time, are costly, and complex and …

The Toyota Production System (Tps) In A Non-Traditional Manufacturing Environment: The Role Of Standardization In The Fast-Food Industry, Kevin Mccracken

Theses and Dissertations--Manufacturing Systems Engineering

The Toyota Production System (TPS), also known as Lean Manufacturing (LM), was founded in the automotive industry and has contributed to Toyota’s decades of success. This has brought much attention to TPS and how this system may be implemented in other industries. Focusing on the TPS foundational element of standardization, this study examines the impact of target cycle time (TCT) on process fluctuation in a fast-food environment. In order to observe the effects of TCT, team members within 3 production lines were timed. Times were measured before and after the addition of a TCT to the Standardized Work (STW) in …

Airflow Impact Upon Remote Laser Welding Quality, Baixuan Yang

Mechanical Engineering Research Theses and Dissertations

Laser induced plasma-plume and condensed particles attenuate the laser beam energy, resulting in keyhole instability and lacking penetration. There are various airflow devices that are currently used in both industrial and laboratory laser welding settings to suppress the detrimental effect of plasma plume and hot spatters. A systematic experimental and numerical study is presented in this dissertation that investigates different external airflow effects on the remote laser welding process used in automotive manufacturing applications.

The vertical airflow impact on the remote laser welding was first studied experimentally. The airflow velocity profiles of a coaxial vertical flow device were measured using …

An Experimental Study Of Fuel Selection For A Gasoline Multi-Mode, Spark Ignited – Compression Ignition Engine, Zachary J. Stanchina

Dissertations, Master's Theses and Master's Reports

In this study of fuels of different reactivities and their performance in a low-temperature combustion (LTC) engine. The engine was a 2.2L CRDI engine code D4HB provided by industry partner Hyundai America Technical Center inc. (HATCI). The engine was instrumented with in-cylinder pressure sensors allowing for monitoring of the combustion process.

First, the engine was operated with standard US pump grade gasoline, Research Octane number (RON) 91 E10, to find initial operation conditions as well as control points of stable operation for daily checks on system conditions.

Tested were 8 different fuel blends, the four base blends were provided by …

Antagonistic Co-Contraction Can Minimize Muscular Effort In Systems With Uncertainty, Anne D. Koelewijn, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

Muscular co-contraction of antagonistic muscle pairs is often observed in human movement, but it is considered inefficient and it can currently not be predicted in
simulations where muscular effort or metabolic energy are minimized. Here, we investigated the relationship between minimizing effort and muscular co-contraction
in systems with random uncertainty to see if muscular co-contraction can minimize effort in such system. We also investigated the effect of time delay in the muscle, by varying the time delay in the neural control as well as the activation time constant.We solved optimal control problems for a one-degree-of-freedom pendulum actuated by two identical …

Nanomechanical Characterization And Comparison Of Additively Manufactured Grcop-42 Alloy, Trupti Suresh Mali

Electronic Theses and Dissertations

In an aggressive thermomechanical environment, the superior mechanical as well as thermal properties of materials play an essential role. GRCop which is a copper-based alloy developed by NASA has the potential to fulfill the requirements necessary for hightemperature applications such as the combustion chamber of liquid rocket engines. The first alloy of this family, GRCop-84 (Cu-8 wt.% Cr-4 wt.% Nb) was discovered followed with the development of GRCop-42 (Cu-4 wt.% Cr, 2 wt.% Nb). The reduction in alloying element percentage enhanced thermal conductivity with less built time while maintaining the strength of the material. The conventional fabrication is replaced with …

Design, Development, And Testing Of Near-Optimal Satellite Attitude Control Strategies, Giovanni Lavezzi

Electronic Theses and Dissertations

Advances in space technology and interest toward remote sensing mission have grown in the recent years, requiring the attitude control subsystems of observation satellites to increase their performances in terms of pointing accuracy and on-board implementability. Moreover, an increased interest in small satellite missions and the recent technological developments related to the CubeSats standard have drastically reduced the cost of producing and flying a satellite mission. In this context, the proposed research aims to improve the state of the art for satellite attitude control methodologies by proposing a near-optimal attitude control strategy, simulated in a high-fidelity environment. Two strategies are …

A Computational Fluid Dynamics Analysis Of The Temperature And Impurity Profiles In The Protodune-Sp Neutrino Detector, Jenna Harrison

Electronic Theses and Dissertations

Computational fluid dynamics (CFD) models of the ProtoDUNE single-phase detector were developed, refined, and analyzed. The ProtoDUNE single-phase detector is a prototype detector that is part of the Deep Underground Neutrino Experiment, an international research collaboration aimed at better understanding neutrinos and the role they play in our universe. The ProtoDUNE single-phase detector is used to gather data and inform design changes for the full-sized far detector prior to its construction. The effects of certain geometric features and heat sources on the thermal profiles within the liquid region of the detector were investigated in a set of parametric studies. The …