Engineering Commons^™

Coulomb Blockade-Mediated Field Emission Sources Using Ultra-Nanocrystalline Diamond, Jevin Jensen

Graduate Research Theses & Dissertations

Coulomb Blockade effects in field emission provide interesting means of achieving brighter electron sources for numerous applications, ranging from vacuum electronics to the next generation of electron beam technology. Microelectronics cleanroom methods are presented in this thesis for production of field emission sources moderated by the Coulomb Blockade. The use of common processes is an essential step toward widespread experimentation with Coulomb Blockade-mediated field emission apparatuses. The main feature to be explored is the use of nano-diamond films for their potential applicability for this desired outcome. Ultra-Nanocrystalline Diamond is used in two different ways to achieve this, both as a …

Artificial Intelligence And Multi-Physics Approach For Electrocoagulation Parameter Selection, Adam Cotton

Graduate Research Theses & Dissertations

Proper treatment of wastewater is crucial to maintain the health of the public and avoid pollution of the environment. Methods like filtering and chemical coagulation have been utilized to treat wastewater, but they have significant limitations such as inefficient treatment of micro-size pollutants, generation of secondary contaminants, and high operation and maintenance costs. The electro-coagulation system which generates coagulants from low-cost aluminum electrodes under the application of a current has received strong attention as a promising water treatment system. However, the EC system has not been fully utilized yet due to lack of understanding and operation guidelines.

In this study, …

Mechanical Behavior Of Metallic Core-Shell Nanoparticles Under Compressive Loading, Phillip Tomich

Graduate Research Theses & Dissertations

Core/shell metallic nanoparticles have been shown to be a promising material type for additive manufacturing in the aerospace and automotive fields. Within additive manufacturing they will be used to accurately make an array of nanoparticles within the grains of metal matrix composites. This in turn will help to strengthen the material while remaining ductility and light weight. In this study, copper/aluminum core/shell nanoparticles are compressed under [100], [110], [111], and [112] directions to showcase their anisotropic material properties. Models of their individual counterparts were also investigated. There are no previous works showing the deformation mechanisms of copper/aluminum core/shell nanoparticles. Molecular …

Analysis Of Localization Algorithms For Wireless Sensor Networks Using Binary Data, Alexander Joseph Hart

Graduate Research Theses & Dissertations

The detection, localization, and tracking of environmental and physical conditions can be accomplished using wireless sensor networks (WSNs). Recent advancements in sensors, processors, and wireless communications have improved the quality and acquisition speed of data in WSNs. However, the data gathered by a WSN is inherently random due to component and environmental variations. Thus, statistical signal processing algorithms are needed to analyze the random data in a robust way. Though many algorithms for the analysis of random data are established and available, they are problem-specific and must be adapted to the application. This thesis provides an analysis of established localization …

Optimizing Battery Performance: Investigating The Long-Term Impacts Of Bidirectional Battery Management Systems On Battery Cells, Drue Nathaniel Haskins

Graduate Research Theses & Dissertations

With the increased use of batteries in everyday life, it is crucial to have a robust and reliable battery system that can continue to power our devices. This paper will investigate the reliability, impact on the batteries, and functionality of the bidirectional battery management system (BMS). The design uses two bidirectional switches for each cell, one in series with the cell and one in parallel with the other bidirectional switch and cell. This will allow the cell to be taken in and out of the circuit for any reason determined by the BMS. Taking the battery in and out of …

Sampling Methods And Transportation Analysis Of Shipping Containers, Omar Roman-Sanchez

Graduate Research Theses & Dissertations

Biomass is a perpetually burgeoning commodity as a sustainable energy resource, but some of the consistent drawbacks are transportation and sampling. The efficiency of pick-up and delivery to conversion facilities needs to be sufficient to allow for longer transport distances. Concurrent work explores the viability of using 20 ft intermodal shipping containers by using a screw auger to pack biomass feedstocks (miscanthus and corn stover) in ¼-scaled containers, which resulted in dry matter packing densities exceeding 8 lb/ft3. Full analysis of compaction energy plus transportation needs was found to understand net positive energy return on investment. To enhance the sampling …

Verification Of Proton Range Predictions In Proton Treatment Planning Using X-Ray Ct Or Proton Ct Imaging, Nicholas S. Yee

Graduate Research Theses & Dissertations

The objective of this paper is to compare the range errors for two treatment plans; one using x-ray CT and the other using proton CT for calculating dose distributions in an animal tissue phantom. We shot 150 MeV proton beam through a meat phantom to a film stack to measure the exponential drop of dose at the Bragg peak until zero dose remained. Plotting the depth dose curves and performing gamma analyses are two ways to quantify the proton range errors when comparing them to depth dose curves from film measurements in the phantom. The depth dose curves give us …

A High-Precision Electron Emission Model: Computational Methods For Nanoscale Structures, Alister J. Tencate

Graduate Research Theses & Dissertations

The high-intensity, high-brightness and precision frontiers for charged particle beams are an increasingly important focus for study. Electron microscopy has demonstrated high quality beams from a single nanotip emitter, and cathodes of structured nanoscale arrays show promise as ultracold electron sources. Optimization of the cathode design for precision applications necessitates a detailed treatment of the interplay between the structure geometry, quantum mechanical emission mechanism, and electromagnetic interactions between the emitted electrons and the boundary interface. This dissertation details the numerical tools developed to simulate these processes efficiently with enough fidelity to be accurate even in the ultracold regime.

Conventional simulation …

Study Protocol To Analyze The Effects Of Occupational Exoskeleton Use On Balance Control, Vishnu Sai Prabhakarababu

Graduate Research Theses & Dissertations

Work-related musculoskeletal disorders (MSDs) represent a prevalent concern affecting a wide range of industries. Occupational exoskeletons have garnered attention as a potential solution to alleviate the risk of MSDs by reducing mechanical loads on susceptible body regions. A critical knowledge gap exists regarding the complex interactions between exoskeleton use and the human body, particularly in work environments prone to slips, trips and falls. This thesis work was part of a funded research aiming to determine the effects of exoskeleton use on balance control. The primary purpose of this thesis work was to determine a reliable maker placement protocol that will …

Strongly Correlated Electron Systems: Rare- And Alkaline-Earth Manganese- And Nickel-Based Perovskite Oxides, Elena Krivyakina

Graduate Research Theses & Dissertations

This work is an academic exploration of the capacity to manipulate the characteristics of strongly correlated electron systems, specifically transition metal perovskite oxides, through chemical substitutions and structural modifications. The high flexibility of the perovskites offers prospects for customizing materials with specific functionalities, thereby holding promise for the advancement of innovative technologies in diverse industries, ranging from electronics and energy to information storage and spintronics. My research focuses on a comprehensive overview of investigations I conducted on three specific compositions, namely alkalineand rare-earth manganese-based and nickel-based oxides, denoted as (Sr, Ba)(Mn, T i)O3−δ, (Y, T b)MnO3+δ, and (Sr, La)N iO3−δ. …

Experimental Evaluation Of Micro-Epidermal Actuators On Flexible Substrates, Courtney D. Bradley

Graduate Research Theses & Dissertations

Does embedding actuators in a flexible substrate increase their performance in hearing aids? What are the differences in damping experienced by actuators of different diameters and at different locations? At what frequency is peak acceleration achieved and what role does the size of the actuator and embedding it in a flexible substrate play? These questions will form the basis of this thesis. This work was done to develop a small non-invasive Band-Aid-©-like hearing aid. The novelty of this device requires a detailed analysis of piezoelectric actuators. This is a continuation of past students’ work on the topic. The main parameters …

Part Design Geometry-Driven Toolpath Optimization For Additive Manufacturing Energy Sustainability Improvement, David Kolawole Somade

Graduate Research Theses & Dissertations

One of the most promising new manufacturing technologies in the past three decades isadditive manufacturing (AM), also commonly known as three-dimensional (3D) printing or rapid prototyping. The energy consumption problem in AM can be significant when it is adopted at the industrial scale or used under resource-restricted conditions. The energy consumption of an AM process is influenced by several factors including bed heating, filament extrusion, material infill, component cooling, etc. All these factors are further determined by the equipment and the toolpath for a specific printing task. Build orientation and tool-path direction are frequently used to optimize part and process …

Diffuse Scattering And 3d-∆Pdf Analyses: Order-Disorder Phase Transitions In (Sr1−Xcax)3rh4sn13 And Nano2, Puspa Upreti

Graduate Research Theses & Dissertations

Classification of structural phase transitions as being of the displacive or order-disorder types is usually done based on spectroscopic measurements performed above the transition. Transitions of the displacive type typically occur when soft phonon modes condense upon approaching the phase transition, whereas those of the order-disorder type are characterized by structures in which the atoms are located randomly above the phase transition at T* at the minima of a multiwell potential. In the ordered state, i.e., when T

We have performed single crystal x-ray scattering experiments and three-dimensional pair distribution functions (3D-∆PDF) analyses to understand the nature of phase transitions …

Design And Development Of A Smartphone App For Health Monitoring And Alerts For Farm Workers, Omer Oztoprak

Graduate Research Theses & Dissertations

This thesis presents the design and development of a novel smartphone applicationfor simultaneous health monitoring and alerts for agricultural workers using multiple wearable sensor devices via Bluetooth Low Energy (BLE). The application combines health data from a range of sensors such as an IMU that detects body movement, a pulse oximeter that captures oxygen saturation and heart rate, and a thermometer that measures body temperature. The software framework is built using Jetpack Compose in Android Studio, and it incorporates the MVVM (Model- View-ViewModel) model to provide optimized data flow and robust efficiency. By integrating the Dagger Hilt Dependency Injection framework, …

A New Boundary Interlock Geometry Design Method For Fdm Multi-Material Part Strengthening, Shivaram Sree Venkata Shanmukha Kakaraparthi

Graduate Research Theses & Dissertations

Multi-material Fused Deposition Modelling (FDM) enables the cost-effective realization of designs in complex geometries built with multiple materials. However, achieving an adequate level of bonding strength between different materials remains a significant challenge. Besides the traditional way of addressing this challenge by strengthening material bonding at the molecular scale by optimizing the printing parameters, introducing a new design methodology that creates stronger multi-material interface geometry could also offer effective solutions. This work studied the mechanical properties of multi-material printed objects, with a particular focus on the interface zone formed between different materials at their geometrical boundaries. A new mathematical simulation …

Biomechanical Evaluation Of Hand Representation For Typing In Virtual Reality, Mobasshira Zaman

Graduate Research Theses & Dissertations

Virtual reality (VR) is becoming popular in the workplace recently. Text entry is thus now important for efficient office use and occupational use of VR, and VR paired with a conventional keyboard is suitable for long text entry. There has been a lack of research on physical demand, posture, motion, and cognitive demand, along with the performance of typing on VR. Presence of virtual hands while typing in VR may affect typing performance, physical demand, and posture. The focus of this study was to evaluate the biomechanical effect of hand representation for typing on VR using a conventional keyboard. Fifteen …

Engagement Detection Using Prosodic Cues: An Approach For Measuring Child Emotional Engagement Level In Child-Robot Interaction Scenario, Mustafa Oztoprak

Graduate Research Theses & Dissertations

The ultimate goal of advanced child-robot interaction is to develop a high-level intelligencecommunication channel in a closed-loop configuration with the child as the focal point of the instructional scenario. This goal can be met by establishing efficient sensing mechanisms on the robot’s side, such as automatic engagement measuring, which will allow the robot to alter its behavior or even the instructional scenario’s execution.Recent researches, regarding engagement recognition systems mostly based on facial or multi-modal features.We would like to investigate this topic using prosodic cues only. We believe speech characteristics are more likely to be related to child speaker engagement level.This …

Experimental Analysis Of Flowing Layer Characteristics In Equilateral Triangular Tumblers For Quasi-2d Macro-Particle Flow, Jason Quinn Ostenburg

Graduate Research Theses & Dissertations

Rotating tumblers are used in a wide variety of industrial applications from mixing anddeburring to flow regulation and storage. Almost all model tumblers previously analyzed, both theoretically and experimentally, had circular cross sections that produced consistent flowing layer dimensions and steady state flow. In contrast, tumblers with triangular cross sections produced unsteady flow as a direct result of the dynamic dimensions of the flowing surface. Although unsteady, the flow produced in triangular tumblers is periodic every 120◦ of rotation after an initial mixing period. The mechanisms by which the flow characteristics vary as a triangular tumbler rotates and the number …

Warm Unit Stand Analysis For Proton Improvement Project Ii, Michael William Pavlick

Graduate Research Theses & Dissertations

The Proton Improvement Project II, commonly referred to as PIP II, is a linear accelerator overhaul at Fermilab to eventually double the output of its existing proton beam to continue to be the leading force in high energy physics. The proton beam is created through a series of high frequency cryomodules that must be connected utilizing a combination of magnets and vacuum pumps to ensure the beam is properly aligned. A housing mechanism for the magnets and vacuum pumps (Warm Units) will be placed between the cryomodules for realignment and require multiple stages of 6 degree-of-freedom adjustment options, to ensure …

Stress Analysis On Walls In Complex Fluids With Fluid-Solid Interaction, Dehong Fang

Graduate Research Theses & Dissertations

The wall shear stress (WSS) in blood vessels influences many biological processes, such as atherosclerosis, clot growth, angiogenesis, aneurysm rupture, and blood cell transport and adhesion. The deformable red blood cells (RBCs) in blood flow make the WSS even more complex. To analyze the WSS in complex fluids with cell suspensions, numerical simulations of blood flows in simple straight channels were conducted, where the fluid-solid interactions were simulated by immersed boundary-lattice Boltzmann method. The spatiotemporal dynamics of WSS were analyzed using dynamic mode decomposition (DMD), which is a technique that can extract the low-rank spatiotemporal features from complex fluids. The …

Investigation Of A Piezoelectric Pressure Sensing To Drive An Igbt Circuit, Sonali Rawat

Graduate Research Theses & Dissertations

In this thesis, piezoelectric pressure sensing element circuit has been proposed and designed to drive the IGBT. The idea behind this work is to integrate and develop the IGBT as pressure sensor. By the application of pressure on the sensing element, the output voltage can turn on the IGBT. The relationship between the force applied and generated voltage of the electromechanical model has been analyzed theoretically.The piezo material used for this work is PZT due its best-known properties. The PZT is also modeled in COMSOL, and its output voltage results are compared with the LT SPICE and theoretical calculation for …

Comparison Of Three Phase Resonant Converter Topologies, Mohammed Adnan Shareef

Graduate Research Theses & Dissertations

There is an increasing demand for power converters with small size, light weight, high conversion efficiency and higher power density. Also, in many applications, there is a need for DC-to-DC converters to accept DC input voltage and provide regulated and/or isolated DC output voltage at a desired voltage level including telecommunications equipment, process control systems, electric vehicles (EVs), renewable energy applications and in industry applications. At higher power levels (e.g., greater than 1kW), three-phase resonant converters have significant advantages over single-phase ones due to reduced component stresses, smaller filter size requirements, and higher power density. The LLC converter is deemed …

Synthesis And Advanced Characterization Of Energy Materials, Erik Sarnello

Graduate Research Theses & Dissertations

Catalysts are used in an extremely broad range of systems including everything from biological systems to industrial processes. An ideal catalyst offers robust stability and high activity. This work focuses on the synthesis and characterization of materials that show promise in the field of catalysis. Advanced synchrotron characterization techniques and unique experimental design are highlighted to provide foundation work that will provide the necessary information to aid in designing and fabricating catalytic materials. Supported metal nanoparticle (SMN) catalysts are enormously crucial for many catalytic applications. However, catalyst deactivation, caused by sintering and coke formation, is a ubiquitous problem that significantly …

Risk-Aware Path Planning For Autonomous Vehicles, Shaghayegh Gaeini

Graduate Research Theses & Dissertations

Autonomous vehicles have been the subject of intense research leading to great improvements in safety, comfort, accessibility, efficiency, etc. Path planning which provides the autonomous vehicle with a smooth, collision-free, and safe path towards its destination, is a crucial part of autonomous vehicles (AVs). Various path planning techniques have been developed in the past decades that can successfully plan a smooth and safe path in various driving scenarios. Nevertheless, these algorithms perform poorly in critical situations where the vehicle needs to quickly make a decision. To address this issue, a couple of algorithms have been proposed to replace the AV’s …

Temperature Analysis Of A Square Lid-Driven Cavity With Particle Suspensions, Justin Kortge

Graduate Research Theses & Dissertations

Computational fluid dynamics (CFD) and discrete element method (DEM) are powerful tools for simulating systems that contain fluids and particles. Studies of particle fluid systems greatly vary in their applications and complexity, and yet there is a scarcity of studies focused on the thermal characteristics of the fluid. A computational analysis is conducted on two-dimensional flow in a square thermal lid-driven cavity to assess the effect of particle suspensions on the thermal characteristics of the cavity. Most studies analyzing the effect of suspensions in a thermal lid-driven cavity treat the medium as a single homogeneous nanofluid. Those that do treat …

A Parametric Study Of Thermochemical Energy Storage Using Chemical Looping For Concentrated Solar Power (Csp) Plants, Imran Anees Mohammed

Graduate Research Theses & Dissertations

The use of conventional fossil fuels to generate power has caused great harm to the environment. These fossil fuels, when burnt, release copious amounts of CO_2, causing global warming. Therefore, it is imperative that current energy sources are substituted with renewable energy sources. However, the critical obstacle with renewable energy sources is their intermittency. Solar energy is being captured through photovoltaic plants and concentrated solar power plants. Photovoltaic plants use batteries, which makes the storage of energy limited. Furthermore, an alternative downside is that the constant use of many batteries will considerably increaseincrease the project’s cost. Concentrated solar power plants …

A Machine Learning Approach To Intended Motion Prediction For Upper Extremity Exoskeletons, Justin Berdell

Graduate Research Theses & Dissertations

A fully solid-state, software-defined, one-handed, handle-type control device built around a machine-learning (ML) model that provides intuitive and simultaneous control in position and orientation each in a full three degrees-of-freedom (DOF) is proposed in this paper. The device, referred to as the “Smart Handle”, and it is compact, lightweight, and only reliant on low-cost and readily available sensors and materials for construction. Mobility chairs for persons with motor difficulties could make use of a control device that can learn to recognize arbitrary inputs as control commands. Upper-extremity exoskeletons used in occupational settings and rehabilitation require a natural control device like …

Upper Body Joint Angle Calculation And Analysis Using Multiple Inertial Measurement Units, Aaron S. Freedkin

Graduate Research Theses & Dissertations

A prominent area in biomechanics revolves around finding solutions to common issues like work-related musculoskeletal disorders (WMSDs). These are common in professions associated with unnatural postures like commercial fishing and farming. Understanding how these professions move on a day-to-day basis can help find solutions to WMSDs. While a motion capture system might be the most common equipment for body posture measurement, it lacks the portability to work in remote environments like commercial fishing and farming. Therefore, joint angle estimation using IMUs (Inertial Measurement Units) could provide a potential alternative.

An IMU consists of a triaxial accelerometer, gyroscope, and magnetometer, which …

Optimize The Niu Split Hopkinson Pressure Bar Apparatus For Conducting High Strain Rate Tensile Test On S304 Foils, Jiale Ji

Graduate Research Theses & Dissertations

Split Hopkinson Bar (SHB) methods are widely used to experimentally characterize the mechanical properties of materials such as metals, concrete, and ceramics undergoing rapid deformation. NIU had a split-Hopkinson tensile apparatus that can conduct coarse tensile test, but it can’t output the useful signal. The aim of this thesis is to optimize the existing apparatus, so the high strain rate tensile tests for the stainless steel 304 can be conducted and useful signal can be got. The alignment of the bars is critical for a good signal that has less noise. To eliminate the noise signal, some accurate fixture is …

Integrating Experimental Parameter Space For Granular Flow Within Polygon Tumblers, Michaela Mcmahon

Graduate Research Theses & Dissertations

Granular flows are complex phenomena bridging both fluid and solid mechanics and observed frequently in the natural world. The transitional dynamics of acceleration from solid body motion to rapid flow can affect many aspects including volume flow rates and mixing behaviors. In order to study the combination of both variables together within polygon-shaped tumblers, control systems are necessary with a corresponding user interface. This thesis reports an interface for changing variable inputs to the system. Predictions of rotation rates with corresponding interfaces with hardware connections are described. Results of image analysis verify output performance that incorporates the following variable changes: …