Engineering Commons^™

Studies Of Exotic Electronic, Optical, And Electrochemical Properties In Nanoparticle Assembly And Graphene, Jay Min Lim

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

It is well known that exotic properties and phenomena emerge as structural dimensions shrink to nanoscales. We self-assembled one-dimensional chains of gold nanoparticles in solution and quantified the growth process by monitoring the redshift of localized surface plasmon resonance (LSPR). Curiously, the redshift stopped while the chains continued to rearrange as manifested by gradual reduction in the LSPR peak. Using electromagnetic simulations, we quantitatively explained the phenomena as a rapid “addition-polymerization” followed by a sharp transition to “condensation-process.” Next, recognizing the significant electric field enhancement in the interparticle gap, a photoluminescent-active Eu³⁺ ion was used to probe Surface-Enhanced Photoluminescence …

Nanoparticle-Based Approaches To Brain Injury And Studies For Improved Detectability Toward Better Delivery Characterization, Hunter A. Miller

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

The clinical translation of nanoparticle (NP) therapeutics for brain injury has been slow despite preclinical promise. The causes of disconnect between preclinical and clinical outcomes is multifactorial, but insufficient delivery is noteworthy. Preclinical delivery characterization often lacks, obscuring mechanisms of failure, slowing development. Multimodal imaging is a promising strategy to improve delivery characterization, combining the strengths of various modalities. Magnetic resonance imaging (MRI) and luminescence imaging are a suitable combination for multimodal imaging, expanding the spatial and temporal resolution of either alone, but further material development is needed to enhance detectability. One problem is the interference of cellular autofluorescence in …

Computational Studies Of Charge-Transfer Mechanisms In Electrochemical Materials, Mohammadreza Reza Nouri

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Understanding charge transfer mechanisms of electrochemical reactions is critical for advancing a variety of electrochemical energy storage and conversion technologies such as water electrolysis, fuel cells, and batteries. (Photo)electrochemical water splitting, involving OER at the anode and HER at the cathode, presents an environmentally friendly way of storing energy from renewable sources in the form of pure hydrogen. While a lot of emphasis has been placed on developing highly active and stable OER/HER catalysts, our atomic-level understanding of the underlying charge transfer mechanisms falls behind.

In this work, we focus on both Faradaic and non-Faradaic charge transfer mechanisms to investigate …

Leveraging Machine Learning And Stochastic Programming To Address Vaccine Hesitancy In Public Health Resource Allocation, Hieu Trung Bui

Graduate Theses and Dissertations

Infectious disease outbreaks highlight the urgent need for effective strategies to distribute vaccines and allocate critical healthcare resources to contain the disease and reduce its negative impacts on the population. Managing these allocations is a significant challenge, especially in marginalized communities facing uncertainty in healthcare demand and logistical constraints. This dissertation addresses these challenges by investigating factors that influence dynamic changes in vaccine hesitancy (VH) and its implications for disease spread and healthcare resource demand. It develops optimization models for vaccine distribution and resource allocation under uncertainty, validated with data from the COVID-19 pandemic in the U.S. The first study …

Investigating Productivity Of Modular Buildings, Sibgat Mehedi Hasan

UNLV Theses, Dissertations, Professional Papers, and Capstones

The modular construction industry has grown substantially, yet understanding of the relationships between project categories, sizes, and productivity remains limited. This study investigates these relationships in both permanent and relocatable modular construction projects across different sectors, including multifamily housing, dormitories, healthcare, education, retail, office, and workforce housing. Data from 303 permanent and 188 relocatable projects in the Modular Building Institute database were analyzed using Kendall's tau-b correlation and linear regression analyses. Key findings reveal that permanent projects outnumber and are generally larger than relocatable ones, with education being the most common project type. Significant positive correlations between project size and …

Development Of A Passive Drag Reduction Modification For The 25° Ahmed Body Using Large Eddy Simulation, Skylar Polek

UNLV Theses, Dissertations, Professional Papers, and Capstones

In the field of automotive aerodynamics, the Ahmed body is a generic vehicle-shaped bluff body which is meant to generalize the rear end of fastback and hatchback vehicles. Specifically, an Ahmed body with a rear slant angle of 25° has seen common use due to its resemblance of common rear windshield shapes as well as its notoriously complex wake structure. This research focuses on simulating the flow over a 25° in various situations with an ultimate goal of drag reduction. First, a simple benchmark of the k-ω shear stress transport (SST), large eddy simulation (LES) with the Smagorinsky-Lilly subgrid scale …

Automated Measurement Of The Water Drop Penetration Time For The Analysis Of Soil Water Repellency, Danxu Wang

UNLV Theses, Dissertations, Professional Papers, and Capstones

In this work, we develop an innovative system for the automated measurement of Water Drop Penetration Time (WDPT) - a parameter that is conventionally used for evaluating soil water repellency (SWR). Increased SWR can be a reason for plant stress and poor crop yields, create a risk of potential water runoff and floods and thus can pose risks to life and property loss. Timely evaluation of soil conditions can save resources and win time for responding to environmental disasters. Manual measurements of WDPT are labor-intensive, subjective, tend to produce variability of outcomes, and also not always available in remote or …

Fracture Behavior Of Advanced Technology Fuels For Light Water Reactors, Adrianna Elizabeth Lupercio

Boise State University Theses and Dissertations

The urgent call to decarbonize our energy infrastructure, while simultaneously meeting growing energy demands, highlights the need for reliable and clean energy sources. Nuclear energy provides reliable, high-capacity baseload electricity while emitting zero greenhouse gases during operation. To adequately meet the energy needs of society and maintain economic viability, it is crucial to enhance the efficiency of nuclear power plant (NPP) operations. Upgrades to NPP operations require near-term Advanced technology Fuel (ATF), such as doped UO₂, to increase the flexibility of plant operation without impacting safety margins.

Small additions of metal oxide dopants are reported to increase grain …

Development Of Recyclable Materials For Industry Using Non-Petroleum Feedstocks, Terra M. Miller-Cassman

Boise State University Theses and Dissertations

Plastics have been an essential material for over 80 years, yet we have been unable to manage the accumulation of plastic waste. The available solutions for recycling or replacing plastics are complex and costly, and thus have not kept pace with the increasing quantity of plastic waste. This dissertation describes a comprehensive, materials design approach to solving the current and future challenges of plastic waste. Recycled and recyclable materials are developed using commercial feedstocks to reduce barriers for industry adoption. In one approach, unsorted municipal solid waste is compressed at a low temperature and pressure to form rigid composite boards …

Development And Implementation Of A Gps-Agnostic Drone Localization System, Alex Peterson

Boise State University Theses and Dissertations

This research develops a GPS-denied state estimation system to localize and orient a drone for touch-based installations on power line towers and cables. As opposed to environments like underground tunnels or building interiors, our system effectively identifies and utilizes sparse landmarks such as towers, cables, and ground features. Our approach utilizes Simultaneous Localization and Mapping (SLAM) to create and reference three-dimensional maps in real time. Specifically, we employ Georgia Tech Smoothing and Mapping (GTSAM), proposed by Georgia Tech's BORG Lab, a factor graph-based data structure consisting of measurement factors and unknown pose variables that we are implementing for solving the …

Selective Bacterial Biofilm Removal Using Image-Guided Detection And Cold Atmospheric Pressure Plasma, Michael Okebiorun

Boise State University Theses and Dissertations

This dissertation explores the use of cold atmospheric pressure plasma (CAP) technology in eradicating bacterial biofilms from tissue surfaces, using Ps. fluorescens on chicken tissue to model human chronic wounds. It introduces a novel image-guided technique for precise biofilm removal, employing trypan blue staining coupled with advanced computer vision analysis, enhancing the CAP treatment's precision and efficacy. The study demonstrates the CAP device's ability to effectively disrupt biofilms through a non-thermal mechanism, based on its electrical characteristics and operational parameters. The success of the treatment is evident in the significant reduction of biofilm thickness of 49 -185 µm, with the …

Evaluation Of Manual Thermal Brake Screening Systems, Jeeyen Koo, David Leddy, Jennifer Walton

Kentucky Transportation Center Research Report

In 2021, manual thermal brake screening systems were installed at Lyon EB and Rowan County weigh stations. Two additional units were installed at Laurel SB and Scott County weigh stations the following year. Although this system is called a thermal brake screening system, its thermal camera images are used to find both brake and tire-related violations. At the time of this project, Lyon (EB), Rowan, and Scott County inspection locations also had tire pressure detection systems in addition to manual thermal brake screening systems. Both systems can be used to identify tire-related violations, but inspectors prefer to use the tire …

Nonplanar Robotic Printing Of Earth-Based Material: A Case Study Using Cob-Like Mixture, Lina Ahmad, Wassim Jabi, Marco Sosa

All Works

The study presents an integration of cob with robotic processes. By challenging conventional monolithic earth-building methods, the study proposes the use of spatial nonplanar formations that are robotically fabricated, presenting an alternative geometric language for earth construction. The research methodology is derived from existing factors within the robotic lab, encompassing both constant and variable parameters. Through an experimental approach, the variables are systematically manipulated while observing the outcomes to identify patterns and relationships. Incremental refinements to the research conditions result in an optimal equilibrium state within the defined lab parameters. An empirical investigation approach serves as the foundation for controlling …

Effortless Mindfulness Toolkit: Easy Meditation Scripts To Begin Each Class., Brett Whysel

Open Educational Resources

The Effortless Mindfulness in the Classroom Toolkit is an open educational resource designed to create happier classrooms, boost student engagement, and foster a sense of community through brief, effective mindfulness exercises. This comprehensive toolkit provides educators with everything they need to seamlessly integrate mindfulness practices into their teaching routines, regardless of prior experience. The toolkit includes introductory slides, 15 ready-to-use meditation scripts, and accompanying audio recordings, covering a variety of mindfulness techniques such as focused breathing, body scans, and loving-kindness meditations. Each meditation is paired with a reflective prompt to deepen student engagement and reinforce the benefits of mindfulness. Additionally, …

High-Power Power Conditioning Systems For Medium-Voltage Applications, Ahmed Rahouma Fares Rahouma

Graduate Theses and Dissertations

The purpose of this dissertation is to address the background, theoretical analyses, design methodologies, and evaluation techniques relevant to high-power power conditioning systems (PCSs) tailored for medium-voltage (MV) applications. Conventional PCSs, reliant on line-frequency transformers (LFTs), suffer from many problems including low power densities, inflexible designs, and scalability constraints. Employing multilevel converters (MLCs), particularly cascaded H-bridge topology, eliminates the need for these LFTs. A key focus lies in minimizing the number of cascaded building blocks by harnessing MV power switching modules. The dissertation makes two primary contributions: firstly, it offers a design methodology for MV-PCS, facilitating the selection of the …

Modeling, Optimization, And Characterization For Choke Horn Antennas, Ibrahim Nasser I Alquaydheb

Graduate Theses and Dissertations

This dissertation presents a comprehensive study focusing on the modeling, optimization, and characterization of choke horn antennas (CHAs). An analytical model designed to capture the parameters of CHA and derive the total radiated fields from the choke and waveguide elements is primarily focused on in this work. Compared to the use of simulation software, such as ANSYS HFSS (High Frequency Structure Simulator) or CST Studio, which employs numerical methods to simulate and calculate antenna performance, numerous advantages are offered by the analytical model. Analytical models provide deeper insight into electromagnetic interactions and the principles governing antenna behavior, leading to a …

Tissue Engineered Models Of Environmental And Metabolism-Driven Cancer-Nerve Crosstalk, Emory Gregory

Graduate Theses and Dissertations

Purpose: Within the last 30 years, cancer-nerve interactions have garnered attention for causing patient pain, increasing the risk of recurrence, and decreasing patient prognosis. There are 2 key forms cancer-nerve crosstalk takes: perineural invasion (PNI), in which cancer cells infiltrate nerves as a route for metastasis, and tumor innervation (TI), in which neurites penetrate solid tumors to promote tumor progression. Present in vitro models of cancer-nerve crosstalk primarily include Matrigel® mouse matrix and collagen I hydrogels; whereas collagen I hydrogels neglect tumor extracellular matrix (ECM) complexity, Matrigel® is controversial for its batch-to-batch inconsistencies and inclusion of experiment-altering growth factors. Decellularized …

Feasibility Study For The Application Of A Solar Powered Absorption Chilling System For Cooling Poultry Houses In Northwest Arkansas, Matthew James Kelly

Graduate Theses and Dissertations

This paper investigates the economic feasibility of utilizing a solar-powered absorption chiller to provide cooling for poultry houses in northwest Arkansas. An existing thermodynamic model of a poultry house was modified to account for cooling. A simulation was performed using actual weather data from Fayetteville, Arkansas for 26 flocks of broilers at four cooling capacities for the 2020, 2021, and 2022 calendar years. Based on the simulation, the savings from reduced electricity use for ventilation and the cost of the required absorption chiller and solar thermal array for an 8-house farm were calculated. While providing cooling was found to reduce …

Evaluation, Modeling And Application Of Gallium Nitride Field Effect Transistor, Geno Guillaume

Graduate Theses and Dissertations

Gallium Nitride (GaN) has emerged as one of the leading materials for power devices due to its wide band gap and high electron mobility. The band gap is the minimum energy required to excite an electron up to a state in the conduction band where it can participate in conduction. Because of this, wide band gap (WBG) materials are favorable for various electrical applications. The market for GaN high-electron-mobility transistor (HEMT) is projected to exceed $1.25 billion by 2027. With the increase of market interest, modern technologies emerge that aim to push the boundaries of efficiency for GaN power devices. …

Development Of A High-Throughput Screening Platform To Profile Gene Delivery And Transcriptional Control In Macrophages, Alexis Ivy

Graduate Theses and Dissertations

Macrophages are an important cell type in the body responsible for orchestrating the inflammatory response and return to homeostasis. Macrophages are often implicated in a multitude of disease pathologies including delayed wound healing, excessive fibrosis, autoimmune disease, and immunosuppression within the tumor microenvironment. Although macrophages have been targeted for therapeutic applications, success in utilizing them has remained elusive due to their relative ease of phenotype switching between inflammatory and anti-inflammatory. The challenge that remains is developing clinically relevant delivery vehicles that can target macrophages without causing a phenotypic switch counter-productive to the desired response. This is especially important when targeting …

Investigating The Detection And Transport Of Low Molecular Weight Species To Better Understand Their Impact On Disease Pathology And Treatment, Haley Michelle Duncan

Graduate Theses and Dissertations

Due to the drastic differences in the projects involved, this dissertation will be split into two sections: Alzheimer’s disease and chronic kidney disease. Each chapter will contain an introduction, materials and methods section, results and discussion, conclusions, and works cited section. The Alzheimer’s disease chapter will also have a supplemental figures section containing the polyacrylamide gels that were silver stained and quantified via ImageJ. The presence of elevated levels of amyloid beta oligomeric species in the brain has been related to the pathology of Alzheimer’s disease. As these oligomeric species are transient in nature, their kinetics pose a challenge to …

Remodel-Fpga: Reconfigurable Memory-Centric Array Processor Architecture For Deep-Learning Acceleration On Fpga, Md Arafat Kabir

Graduate Theses and Dissertations

Deep-Learning has become a dominant computing paradigm across a broad range of application domains. Different architectures of Deep-Networks like CNN, MLP, and RNN have emerged as the prominent machine-learning approaches for today’s application domains. These architectures are heavily data-dependent, requiring frequent access to memory. As a result, these applications suffer the most from the memory bottleneck of the von Neumann architectures. There is an imminent need for memory-centric architectures for deep-learning and big-data analytic applications that are memory intensive. Modern Field Programmable Gate Arrays (FPGAs) are ideal programmable substrates for creating customized Processor in/near Memory (PIM) accelerators. Modern FPGAs contain …

Development Of Iii-V And Iv Epitaxy On Sapphire Technology, Emmanuel Wangila

Graduate Theses and Dissertations

This research presents comprehensive insights into the epitaxial growth of germanium (Ge) on c-plane sapphire substrates using molecular beam epitaxy (MBE). The direct growth of Ge on sapphire typically yields three-dimensional (3D) Ge islands with diverse growth directions, multiple primary domains, and twinned crystals. However, incorporating a thin AlAs nucleation layer proves instrumental in enhancing surface and material quality. With a 10 nm AlAs layer, the achieved surface exhibits improved characteristics, including a smoother surface, single epitaxial orientation, sharper rocking curve, and a single domain. This study surpasses previous works by achieving a single primary domain and reducing twinning. Furthermore, …

Molecular Beam Epitaxy Of Gesn On Iii-V Substrates For Photonic Applications, Calbi Gunder

Graduate Theses and Dissertations

This dissertation explores the advancement of germanium-tin (GeSn) as a tuneable narrow bandgap material, crucial for the development of high-efficiency photodetectors and laser devices in near- and mid-infrared technologies. We investigate the synthesis challenges, particularly the lattice mismatch between GeSn alloys and substrates, which significantly affects their crystalline and optical qualities. Through molecular beam epitaxy, we examine the growth of Ge and GeSn on GaAs (001) substrates, employing Ge/GaAs and Ge/AlAs buffer layers to investigate these challenges. Our findings, characterized by X-ray diffraction, atomic force microscopy, reflection high-energy electron diffraction, and photoluminescence, demonstrate the production of high-quality Ge layers, achieving …

Optimization Of And Mechanistic Insights Into Photocatalytic And Non-Thermal Plasma Degradation Of Organic Pollutants For Sustainable Wastewater Treatment, Yiting Xiao

Graduate Theses and Dissertations

Water pollution by organic pollutants poses a significant environmental threat, necessitating the development of advanced treatment technologies to ensure sustainable and efficient remediation. This dissertation explored innovative approaches to enhance the degradation of organic pollutants through the integration of photocatalytic and plasma-assisted systems, with a focus on optimizing these processes using methodologies ranging from response surface methodology (RSM) to advanced machine learning techniques. The first part of the dissertation investigated the degradation of organic pollutants in flocculated liquid digestate using photocatalytic titanate nanofibers (TNFs) synthesized via a hydrothermal method. This study represents the first application of TNFs, with a bandgap …

Synthesis Of Nanoparticles And Their Applications In Power Module Packaging And Organic Electronics, Xinsong Zhang

Graduate Theses and Dissertations

Nanoparticles can greatly change the properties of regular materials due to their special structures. In this research nanoparticles, such as silver nanowires, silver nanospheres and expanded graphite, are used in interconnection materials for power module packaging, and in conductive films for organic electronics. Silver nanowires synthesized by polyol synthesis, are used as fillers in micron silver paste. The electrical and mechanical properties of the sintered hybrid silver paste are investigated and compared with those of micron silver paste. The composites of silver nanospheres and expanded graphite are mixed with PEDOT:PSS solutions in 5 different weight ratio. The electrical and optical …

Esd-Robust 4h-Sic Low-Voltage Cmos Technology Development For High Temperature, Hui Wang

Graduate Theses and Dissertations

This dissertation explores the development and optimization of electrostatic discharge (ESD)-robust, low-voltage CMOS technology using 4H-silicon carbide (SiC) tailored for high-temperature applications, addressing the critical need for reliable semiconductor devices in harsh environmental conditions. The advent of SiC as a semiconductor material offers significant advantages over traditional silicon (Si) in harsh environments, including higher thermal conductivity, greater electron mobility, and improved electrical characteristics at elevated temperatures. This research explores the integration of 4H-SiC into CMOS technology to enhance device reliability and performance in extreme conditions such as those found in aerospace, automotive, and energy sectors. The study begins with a …

Computational Alchemy: Pioneering Spintronic, Thermoelectric, And Optoelectronic Materials Design Through First-Principles Calculations And Machine Learning, Eesha Sanjay Andharia

Graduate Theses and Dissertations

Intelligent materials discovery and design plays a pivotal role in advancement of spintronics, optoelectronics and thermoelectric devices and technology. In this study, we investigate three types of materials using first principles calculations. First, the structural, electronic, and magnetic properties of CrTiCoZ (Z = Al, Si) equiatomic quaternary Heusler alloys were investigated. CrTiCoAl compound was found to exhibit a half metallic ferromagnetic structure and Curie temperature above room temperature, which makes it an ideal candidate for magnetic tunnel junction, the basic building block of Spintronic devices. Second, we use Green’s function to obtain the finite temperature phonons by including quartic anharmonicity …

Ω-Shaped Rogowski Coil Current Sensor Optimization Design In Power Electronics Applications, Xia Du

Graduate Theses and Dissertations

Accurate switching current measurement plays a pivotal role in characterization of power devices, overcurrent protection, and real-time control of system-level operations in power electronics applications. However, the ongoing revolution in power electronics, driven by the emergence of wide bandgap power devices operating at megahertz (MHz) switching frequencies, introduces challenges for current sensor design. The urgent issue now is the need to increase current sensor bandwidth significantly to adeptly capture the rapid switching speed current. Additionally, the trend towards high power density and compact power converters in various applications demands current sensors that are not only compact and nonintrusive but can …

Development Of A Turning Movement Estimator, Somayeh Nazari Enjedani

Boise State University Theses and Dissertations

Turning Movement (TM) counts at intersections are crucial for several reasons. There has been extensive research on this topic throughout the history of traffic research, which reflects its importance in transportation engineering and urban planning. It can be said that one of the most significant applications of TMs is signal timing at intersections. Signal timing design requires data on the turning decisions of vehicles that travel through intersections to allow enough time for each movement at the intersection. Most of organizations around the USA are still applying traditional methods for collecting TM data, such as manual counts. These methods are …