Mechanical Engineering Commons^™

Hobby Grade Lithium-Ion Batteries For Spacecraft Applications: Establishing An Automated Electrical Characteristics Testing Procedure For Flight Acceptance Of Non-Space-Grade Small Secondary Batteries, Braidon Hughes

Graduate Theses and Dissertations

Li-ion batteries are widely used due to the large amount of rechargeable energy they pack into a small, light package. This higher energy density makes Li-ion batteries ideal for small satellite applications, specifically CubeSats. CubeSats have grown in popularity in higher level education due to the National Aeronautics and Space Administration’s implementation of the Cube Satellite Launch Initiative, making it easier and cheaper to conduct small, low orbit missions. Because these CubeSats are occupying the same space as a crewed spacecraft, it is imperative that they are safe. There are numerous reports of Li-ion batteries creating fires that result in …

Deep Learning Strategies For Pool Boiling Heat Flux Prediction Using Image Sequences, Connor Heo

Graduate Theses and Dissertations

The understanding of bubble dynamics during boiling is critical to the design of advanced heater surfaces to improve the boiling heat transfer. The stochastic bubble nucleation, growth, and coalescence processes have made it challenging to obtain mechanistic models that can predict boiling heat flux based on the bubble dynamics. Traditional boiling image analysis relies on the extraction of the dominant physical quantities from the images and is thus limited to the existing knowledge of these quantities. Recently, machine-learning-aided analysis has shown success in boiling crisis detection, heat flux prediction, real-time image analysis, etc., whereas most of the existing studies are …

Respiratory Compensated Robot For Liver Cancer Treatment: Design, Fabrication, And Benchtop Characterization, Mishek Jair Musa

Graduate Theses and Dissertations

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death in the world. Radiofrequency ablation (RFA) is an effective method for treating tumors less than 5 cm. However, manually placing the RFA needle at the site of the tumor is challenging due to the complicated respiratory induced motion of the liver. This paper presents the design, fabrication, and benchtop characterization of a patient mounted, respiratory compensated robotic needle insertion platform to perform percutaneous needle interventions. The robotic platform consists of a 4-DoF dual-stage cartesian platform used to control the pose of a 1-DoF needle insertion module. The active …

Thermometry Via Diffusion In Ferrous Core-Shell Nanoparticles For Induction Heating Applications, Hayden Carlton

Graduate Theses and Dissertations

Induction heating causes the release of enormous amounts of heat from dispersed magnetic nanoparticles. While the rate of heat transfer can be easily quantified calorimetrically, measuring the temperature of the nanoparticles on the nanoscale presents experimental challenges. Fully characterizing the temperature and thermal output of these magnetic particles is necessary to gauge overall heating efficiency and to provide a more holistic understanding of heat transfer on the nanoscale. Herein, this dissertation seeks to develop a novel nanoparticle thermometry technique, which correlates diffusion behavior in core-shell nanoparticles to local temperature. Initial measurements suggested that heating silica capped ferrous nanoparticles (SCNPs) via …

Nonmetallic Jet Impingement Thermal Management For Power Electronics Via Additive Manufacturing, Reece Whitt

Graduate Theses and Dissertations

The increase in energy demanded by transportation and energy sectors has necessitated highly efficient thermal management for reliable power electronics operations. Conventional cooling techniques are limited by their inability to target switching location hot spot temperatures, leading to non-uniform thermal gradients. These devices, such as cold plates and heat sinks, also utilize heavy metallic structures that can accentuate electromagnetic interferences generated by high voltage switching processes. This work proposes a non-metallic jet impingement cooler for more customized thermal management, while simultaneously reducing the harmful effects of electromagnetic interferences. Additive manufacturing is utilized to enable jet impingement zones to target individual …

Combined Stressors In Reliability Failure Modes In Flip-Chip Electronic Packaging, Mahsa Montazeri

Graduate Theses and Dissertations

The trend toward miniaturization of electronic devices to fulfill Moore’s law introduces new reliability concerns to the electronic packaging process while worsening existing primary challenges. In solder interconnect specifically, temperature cycling is one of the prominent failure threats. However, with further downscaling of the flip-chip solder connections, electromigration also present a precarious failure mode in these interconnects. On the other hand, understanding the degradation mechanism in solders is crucial for the power electronic products' reliability considering the industrial tendency to replace wirebonds with solder attachment while improving the current carry capacity. This dissertation utilizes FEA simulation and an experimental approach …

Mission Profile Effects On Automotive Drivetrain Electronics Reliability: Modeling And Mitigation, Bakhtiyar Mohammad Nafis

Graduate Theses and Dissertations

The reliability of electronic devices is dependent upon the conditions to which they are subject. Temperature variations coupled with differences in thermal expansion between bonded materials results in thermomechanical stresses to build up, which can instigate failure in the interconnects or other critical regions. With the move towards electrification in the automotive industry, there is the increasingly important consideration of powertrain electronics reliability, the pertinent conditions being governed by the drive cycle or mission profile of the vehicle. The mission profile determines the power dissipated by the electronic devices, which determines the peak and mean temperature, temperature swing and the …

Identification Of Phosphorous Loading Point Source Facilities To 303(D) Listed Nutrient Impaired Waters Through Watershed Delineation Using Arcgis For Life Cycle Assessment Applications, John Zimmerman

Chemical Engineering Undergraduate Honors Theses

The work done for this project is part of a larger “life cycle assessment (LCA) of novel electrochemical phosphorus recovery technology at the wastewater treatment plant and U.S. watershed scales” (Morrissey 2019). The goal of that LCA is to determine “environmental impacts of implementing electrochemical struvite recovery at the wastewater treatment plant, U.S watershed, and global scales” (Morrissey 2019). This project’s goal is to identify locations deemed more sensitive to eutrophication impacts. The results will be used as part of the life cycle inventory (LCI) accounting for geographically explicit phosphorus flows. The waters identified as impaired were sourced from the …

Tribological Studies Of Thick Polytetrafluoroethylene Coatings Enhanced By Polydopamine And Nanoparticles, Sujan Kumar Ghosh

Graduate Theses and Dissertations

Polytetrafluoroethylene (PTFE) is a popular low friction solid lubricant with high chemical and thermal stability. Thick PTFE coatings have the potential for many tribological applications, such as replacing Tin-based Babbitt materials in journal bearings. However, the weak bonding strength to the substrate and the high wear rate of PTFE coatings are current limiting factors. The lack of understanding of their tribological properties and wear mechanisms in oil-lubricated conditions and how coating thickness affects the tribological performance further hindered the use of PTFE coatings. In this dissertation, polydopamine (PDA), a bio-inspired adhesive, is used as an underlayer for or as a …

Development Of Novel Battery Materials For Lithium-Ion Batteries And Beyond, Jiyu Cai

Graduate Theses and Dissertations

As fossil fuels are depleting and causing environmental issues, it becomes imperative to widely implement renewable energies (e.g., solar and wind power). In this context, electrical energy storage (EES) systems are essential to accommodate the intermittent supply and uneven distribution of renewable energies. To this end, high-energy-density EES devices are highly demanded, such as rechargeable batteries. This dissertation presents my efforts in developing novel battery materials for lithium-ion batteries (LIBs), sodium-ion batteries (SIBs), and solidstate lithium batteries (SSLBs). These efforts include electrochemical evaluations of battery materials, surface modifications of electrodes via atomic layer deposition (ALD), and advanced characterizations of batteries …

Phase-Field Modeling Of The Polymer Membrane Formation Process For Micro- And Ultra-Filtration, Michael Rosario Cervellere

Graduate Theses and Dissertations

Porous polymer membrane filters are widely used in separation and filtration process. Micro- and ultra-filtration membranes are commonly used in biopharmaceutical applications such as filtering viruses and separating proteins from a carrier solution. The formation of these membrane filters via phase inversion is a complex and interconnected process where varying casting conditions can have a wide variety of effects on the final membrane morphol- ogy. Tailoring membrane filters for specific performance characteristics is a tedious and time consuming process. The time and length scales of membrane formation make it extremely difficult to experimentally observe membrane formation. Modeling the membrane formation …

Influence Of Extracellular Matrix Stiffness And Topography On Neuronal Cell Behavior And Neurite Outgrowth, Mohan Yasodharababu

Graduate Theses and Dissertations

The focus of regeneration therapy for traumatic brain injuries and Alzheimer's disease is on the promotion and growth of neuronal cells. In vitro research attempts to improve this by modifying the stiffness and topography of the extracellular matrix (ECM). However, the limitations of in vitro experiments make it difficult to control the individual factors influencing neuronal cell growth. A computational model can be used to decouple individual factors and study them individually to gain a better understanding of the mechanics between the neuronal cell and ECM, which will aid in the design of in vitro experimental studies.

This study develops …

Material Detection With Thermal Imaging And Computer Vision: Potentials And Limitations, Jared Poe

Graduate Theses and Dissertations

The goal of my masters thesis research is to develop an affordable and mobile infraredbased environmental sensoring system for the control of a servo motor based on material identification. While this sensing could be oriented towards different applications, my thesis is particularly interested in material detection due to the wide range of possible applications in mechanical engineering. Material detection using a thermal mobile camera could be used in manufacturing, recycling or autonomous robotics. For my research, the application that will be focused on is using this material detection to control a servo motor by identifying and sending control inputs based …

Computational Frameworks For Multi-Robot Cooperative 3d Printing And Planning, Laxmi Prasad Poudel

Graduate Theses and Dissertations

This dissertation proposes a novel cooperative 3D printing (C3DP) approach for multi-robot additive manufacturing (AM) and presents scheduling and planning strategies that enable multi-robot cooperation in the manufacturing environment. C3DP is the first step towards achieving the overarching goal of swarm manufacturing (SM). SM is a paradigm for distributed manufacturing that envisions networks of micro-factories, each of which employs thousands of mobile robots that can manufacture different products on demand. SM breaks down the complicated supply chain used to deliver a product from a large production facility from one part of the world to another. Instead, it establishes a network …

High Temperature Degradation In Gan-Based Hall Effect Sensors, Alexis Anne Krone

Graduate Theses and Dissertations

This research focuses on understanding the effects of accelerated aging through temperature and environment on novel gallium nitride-based Hall effect magnetic field sensors and determining device reliability under electric vehicle operating conditions. The device reliability was modeled using accelerated aging for the temperatures of 200 °C, 350 °C, 450 °C, and 600 °C under various time steps unique to each temperature and either air, which is identical to operating circumstances, or argon, which would model the hermetic packaging environment. Using a high temperature furnace and oven, devices underwent high temperature storage tests at a chosen temperature and time step. Afterwards, …

An Investigation Of Testing Parameters On The Frictional Properties Of Patterned Core-Shell Nanostructures, Colin Phelan

Graduate Theses and Dissertations

Friction tests are a beneficial means to analyze the tribological characteristics and advantages of materials and textured surfaces. However, the selected test parameters can significantly influence the results. This work explores the significance of the friction testing parameters on the frictional performances of core-shell nanostructure-textured surfaces (CSNTSs). Several applied normal loads (10 μN, 100 μN, and 500 μN) and diamond counterface indenter tip radii (1 μm, 5 μm, and 20 μm) were selected for the testing of Al/diamond-like-carbon (DLC) and Al/amorphous silicon (a-Si) CSNTSs. The measured friction values of the CSNTSs were then compared to a matching Al/DLC film and …

Development Of A Solidworks Simulation Toolkit For A Sophomore Level Biomedical Engineering Course, Jordan Crosby

Biomedical Engineering Undergraduate Honors Theses

In the engineering industry, computer-aided design (CAD) programs are used to create models and create virtual experiments or studies that allow engineers to observe the real behavior of parts or assemblies under certain conditions. Companies hire students with experience in CAD, as professionals believe that CAD experience is beneficial [1,2]. SolidWorks is among the most popular CAD software used by engineers. SolidWorks has multiple functionalities that also allow for finite element analysis dependent on the license. Users can create simulation studies in SolidWorks Simulation that can be used as an accurate approximation for real results.

The goal of this study …

Performance And Economics Of Solar Inverters And Module Level Power Electronics In A 1 Mw Photovoltaic System, Maxwell Criswell

Biological and Agricultural Engineering Undergraduate Honors Theses

Photovoltaic solar panels convert sunlight to electricity in the form of direct current; therefore, a necessary component of every photovoltaic system is an inverter to convert the electricity to usable alternating current. There are various commercially available inverter technologies manufactured today such as microinverters, string inverters, and central inverters, as well as module level power electronic devices such as DC optimizers that are capable of improving system performance in string and central inverter systems. This thesis compares the performance and economics of five different inverter and module level power electronic systems through model simulation using Helioscope software. The five alternatives …

Designing Cryogenic Strain Device For 2d Materials, Jake Carter

Mechanical Engineering Undergraduate Honors Theses

The Churchill lab working within the Physics Department at the University of Arkansas is working to create important quantum states including weak topological insulators (TIs) through the use of symmetry engineering and topological electronic states in two-dimensional (2D) crystals of WHM materials. Experimental results of these topological states have been obstructed due to the difficulty to perform controlled in situ strain. This project strives to create a mount to utilize a piezoelectric nanopositioner within cryostats achieving an in situ strain that creates the quantum states the lab is looking to observe. This report also examines the necessary equations to determine …

Nanoscratch Study Of Diamond-Like Carbon Coatings With A Polydopamine + Sio2 Adhesive Underlayer, Anna Fisher

Mechanical Engineering Undergraduate Honors Theses

Diamond-like carbon (DLC) coatings have a wide array of desirable characteristics such as low friction, high hardness, and scratch resistance. Due to high residual stress and thermal mismatch, DLC films experience adhesion difficulties when bonded with metallic substrates, leading to cracking and delamination. In this study, the properties of a new coating with a polydopamine underlayer and silica nanoparticles bonded to a stainless-steel substrate (PDA+SiO2/DLC) were studied alongside three other samples, one with a polydopamine underlayer (PDA/DLC), one with a trimethylsilane (TMS) underlayer (TMS/DLC), and one with no underlayer (DLC only). Nanoscratch tests were performed with a 1 μm spheroconical …

Transient Performance And Melt Front Characterization Of Phase Change Materials, Tyler Stamps

Mechanical Engineering Undergraduate Honors Theses

Thermal management systems are often over-designed for average use in order to handle spikes in heat generation, which increases the spatial and financial requirements. One way to mitigate this is via the use of phase change materials (PCMs) as thermal buffers and storage media. This material type exhibits excellent latent heat at the sacrifice of conductivity. The present paper examines the melt front behavior of a common solid to liquid PCM, paraffin, experimentally and numerically. The experimental scenario was a block of PCM with a constant temperature heat flux introduced on one end and a constant temperature cold boundary condition …

Design And Control Of A Peristaltic Pump To Simulate Left Atrial Pressure In A Conductive Silicone Model, Jeremy Collins

Mechanical Engineering Undergraduate Honors Theses

According to the CDC, atrial fibrillation is responsible for more than 454,000 hospitalizations and approximately 158,000 deaths per year. A common treatment for atrial fibrillation is catheter ablation, a process in which a long flexible tube is guided through the femoral artery and to the source of arrhythmia in the heart, where it measures the electrical potential at various locations and converts problematic heart tissue to scar tissue via ablation. This paper details the design and control of a low-cost ($400) peristaltic pump system using repetitive control to replicate blood pressure in the left atrium in a conductive silicone model …

Improving The Performance Of An Ead Aircraft By Use Of A Retractable Electrode System, Michael Alexander Fredricks

Mechanical Engineering Undergraduate Honors Theses

Electroaerodynamic (EAD) propulsion is a growing area of research for small, low powered aircraft. Recent tests of EAD aircraft have demonstrated low performance in unpowered, gliding flight. The purpose of this paper is to investigate the effect of a retractable electrode system on the flight performance of an EAD aircraft. An analysis of electrode drag contribution on the MIT ionic wind plane’s performance predicts a maximum lift to drag ratio of 22, with the addition of a retractable electrode system, for a similarly sized and modeled EAD aircraft. An experiment is developed using a prototype aircraft, launcher, and retraction system …

Thermal Testing And Characterization Of Nanoparticles Synthesized For Biological Treatment, Tonie Butler

Mechanical Engineering Undergraduate Honors Theses

The overall goal of this research project is to synthesize iron core, silica capped nanoparticles that, when they are exposed to a particular magnetic field, will react by increasing in temperature and emitting substantial thermal output. They will be injected into the human body for biological benefit by targeted thermal radiation. Once in the human body, ideally, they will be able to target a specific area, and then a magnetic field will be applied to induce thermal output through the process of hyperthermia. As the nanoparticles emit heat, they will mimic the natural bodily behavior seen by way of hyperthermia, …

Mathematical Modeling Of A Two Wheeled Robotic Base, Kathryn Remell

Mechanical Engineering Undergraduate Honors Theses

This thesis presents the concept of using a two wheeled robot on the moon and briefly explores the requirements for successful long term operation in a lunar environment. The mathematical model for the motion of a robot with two fixed wheels on a differential drive with in a global reference frame. The robot is assumed to be balancing a platform so the mathematical model to balance the platform with wheel motors is also developed and briefly evaluated.

Characterizing High Entropy Alloys For Hypersonic Applications, Katherine Pettus

Mechanical Engineering Undergraduate Honors Theses

In this paper, the properties of a new and broad class of materials, high entropy alloys (HEAs), were investigated and evaluated for hypersonic applications. The plan was to identify candidate hypersonic HEAs and model the high-temperature strength using new advanced material models that account for asymmetry and anisotropy characterized with available test data. After accessing a local database of HEAs and their material properties in collaboration with Dr. Gorsse et al., it was realized the knowledge of HEAs is currently very broad but lacks depth. While hundreds of HEAs have been created and tested, none so far have both sufficient …

Noise Control In Sorting Conveyors, Eyra Herrera

Mechanical Engineering Undergraduate Honors Theses

E-commerce has increased the necessity of effective material handling equipment in warehouses and distribution centers. Sorter conveyors systems facilitate material handling by providing a reliable and automated system to classify and distribute products in a gentle and rapid manner. With the steady increase of speed in sorter conveyors to satisfy today’s industry demand, some systems have started to produce high noise levels that could potentially affect workers’ health. Since decreasing the speed of these conveyors is not a viable option to decrease noise in sorter equipment, industries have opted to find other ways to apply noise control to their equipment. …

Algorithm Development Of Topology Optimization For Pcm Based Heat Sinks, Diego L. De Los Reyes

Mechanical Engineering Undergraduate Honors Theses

With the inherent usage of the computer when dealing with additive manufacturing, it only makes sense to use that higher computing power through simulation and iterative design to use the mathematical concept of topology and optimize the kind of geometry and shapes to be produced for a certain application, especially thermal ones since most 3D printing applications focus on purely the mechanical. To determine what the shape will be, an objective function of how much heat can be dispersed from a hypothetical heat source, assumed to be a type of electronic device, is maximized while being constrained by other variables, …

Economic Feasibility Of Mixed Plastic Waste Pyrolysis Using Twin Reactor System In Northwest Arkansas, Carol Rogers, Patricia Means, Renato Gonzalez, Kaida Sheets, Hayden Townsend

Chemical Engineering Undergraduate Honors Theses

Plastic waste generation is increasing at an unsustainable rate while recycling solutions remain stagnant. As a chemical means of recycling, mixed plastic waste pyrolysis can generate synthetic oil appropriate for use as fuel in power generation from plastic waste that otherwise accumulates in landfills. With the scaling of a commercial plastic pyrolysis process in Northwest Arkansas (NWA) modeled after an operational sawdust pyrolysis unit in Huntsville, Arkansas, economic analysis resulted in 26.3% internal rate of return. Therefore, construction of a commercial mixed plastic-to-fuel pyrolysis plant is economically justified and should be pursued. To effectively implement the proposed design, NWA must …