Engineering Commons^™

Cost-Risk Analysis Of The Ercot Region Using Modern Portfolio Theory, Megan Sickinger

Master's Theses

In this work, we study the use of modern portfolio theory in a cost-risk analysis of the Electric Reliability Council of Texas (ERCOT). Based upon the risk-return concepts of modern portfolio theory, we develop an n-asset minimization problem to create a risk-cost frontier of portfolios of technologies within the ERCOT electricity region. The levelized cost of electricity for each technology in the region is a step in evaluating the expected cost of the portfolio, and the historical data of cost factors estimate the variance of cost for each technology. In addition, there are several constraints in our minimization problem to …

Synthesis Of Bimetallic Nickel And Cobalt Phosphide Nanostructures For Electrocatalysis, Sarah Meixin York

Graduate Theses and Dissertations

Transition metal phosphides have become a new class of materials to be considered as promising catalysts for a number of applications including electrochemical hydrogen evolution (HER). Electrocatalysis in hydrogen evolution is a heavily studied field due to the increasing desire to develop more efficient and more cost-effective catalysts for clean hydrogen production. This project develops a chemical approach to synthesizing bimetallic cobalt-nickel phosphide nanostructures for their use in HER. The synthesis is accomplished by thermal decomposition of the metal precursors in the presence of carbon monoxide (CO) and trioctyl phosphine (TOP). The resulting nanostructures were characterized using transition electron microscopy …

Towards Side-Channel Infrastructure For Software Implementations Of Pqc Algorithms, Tristen Teague

Graduate Theses and Dissertations

Post-Quantum Cryptography (PQC) is a new class of asymmetric cryptography algorithms that are supposed to be secure against both classical computers and quantum computers through Shor’s algorithm. Since PQC algorithms are currently being standardized, they will replace older standardized asymmetric algorithms (such as RSA) and will be deployed within the digital infrastructure. Before implementations of the PQC algorithms are placed into the infrastructure, they must undergo evaluation of both performance and security. One such security issue that needs large investigation before deployment are side-channels. Side-channel attacks (SCA) are a method of gathering information from the implementation, such as power-consumption and …

Explainable Machine Learning For The Regulatory Environment: A Case Study In Micro-Droplet Printing, Elaine Harris, Darragh F. Ryan, Gerard M. O'Connor

Articles

Micro-droplet printing remains an invaluable tool for the additive manufacturing industry due to its versatility, efficiency and cost-effectiveness. The design and deployment of a disposable micro-droplet dispenser seeks to facilitate a quick and easy way to alternate between different printing materials (such as ink, metals, bio-materials, pharmaceuticals, etc.) without the need for thorough cleaning or separate delivery systems. While this works well in principle, in practice achieving consistent performance between dispensers can prove challenging. This paper aims to tackle this issue through the use of Machine Learning (ML) in order to (1) build a model that predicts dispenser performance from …

Suppressing Reactive Oxygen Species Via Application Of Antioxidant Supramolecular Polymers, Zacchaeus Wallace

Honors Theses

Cardiovascular diseases along with various other disease conditions are characterized by an upregulation in reactive oxygen species (ROS), which can overwhelm homeostatic processes in the body, resulting in cellular apoptosis and severe oxidative damage. The lack of clinically approved treatments to regulate or alleviate this elevated ROS presence underscores the need for novel therapeutic strategies. While antioxidants promote cell rescue through ROS scavenging, their clinical translation is impeded by insufficient bioavailable concentrations at the source of injury. The opportunity to apply antioxidant supramolecular polymers of peptide amphiphiles (PAs) is an exciting prospect of research to combat corresponding issues. For this …

“How Are High School Counselors Prioritizing The Information Relevant To Stem Career Preparation In Their Communication With Stem-Interested African American Students?”, Wysheka Austin

All Dissertations

Although African Americans and other minoritized groups have gradually increased in the number of students graduating with a Science, Technology, Engineering, and Mathematics (STEM) degree over the years, these groups remain underrepresented in STEM. Among the many factors contributing to the lack of representation is “college readiness,” which includes academic preparation and awareness of the necessary steps needed for college admission and career preparation [5]. South Carolina policy only considers academic preparation in their assessment of college readiness. To measure academic preparation of any student, the state relies on standardized test scores and advanced course taking without regard to subject. …

Mammary Epithelial Cell Derived Extracellular Vesicles Influence Tumorigenic Phenotype Suppression In Her2-Positive Breast Cancer Cells, Brenda Okereke

All Dissertations

On a global scale, breast cancer remains the most commonly diagnosed cancer in the world. In 2020 alone, there were over 2.3 million new cases of breast cancer seen and a total of 685,000 deaths globally, this represents 16% or 1 in every 6 cancer deaths seen in women. By 2040 it is projected that the breast cancer burden will rise by over 40% to exceed 3 million new cases a year. Further understanding of the underlying biology and mechanisms behind tumor progression and breast cancers such as HER2+ breast cancer would allow for new therapeutic treatment targets to emerge. …

Identifying Temporomandibular Disorder Morphological Risk Factors Via Explainable Deep Learning And Multiscale Biomechanical Modeling, Shuchun Sun

All Dissertations

Clarifying multifactorial musculoskeletal disorder etiologies supports risk analysis and development of targeted prevention and treatment modalities. Deep learning enables comprehensive risk factor identification through systematic analysis of disease datasets but does not provide sufficient context for mechanistic understanding, limiting clinical applicability for etiological investigations. Conversely, multiscale biomechanical modeling can evaluate mechanistic etiology within the relevant biomechanical and physiological context. We propose a hybrid approach combining 3D explainable deep learning and multiscale biomechanical modeling; we applied this approach to investigate temporomandibular joint (TMJ) disorder etiology by systematically identifying risk factors and elucidating mechanistic relationships between risk factors and TMJ biomechanics and …

Green Chemistry Design Of Epoxies From Biomass For Circular Economy, Kavya Ganesan

All Dissertations

The commercial epoxies market in automobiles has been growing mainly in terms of usage as automotive coatings and lightweight composite structures manufacturing. Most of these commercial epoxies are bisphenol-based. Bisphenol-based epoxies are a class of high-performance polymer materials that, when cured, yield thermosets with high mechanical, thermal and chemical resistance properties. Roughly, North America produces around 123 billion pounds of these epoxies which are used in various industrial applications like coatings, composites, structural parts, automotive, electronics, construction etc. These epoxies are mainly manufactured from bisphenol-A (BPA) and epichlorohydrin (EPH). These raw materials are sourced from fossil fuel resources and are …

Numerical Simulation Of Laser Induced Elastic Waves In Response To Short And Ultrashort Laser Pulses., Alireza Zarei

All Dissertations

In an era of intensified market competition, the demand for cost-effective, high-quality, high-performance, and reliable products continues to rise. Meeting this demand necessitates the mass production of premium products through the integration of cutting-edge technologies and advanced materials while ensuring their integrity and safety. In this context, Nondestructive Testing (NDT) techniques emerge as indispensable tools for guaranteeing the integrity, reliability, and safety of products across diverse industries.

Various NDT techniques, including ultrasonic testing, computed tomography, thermography, and acoustic emissions, have long served as cornerstones for inspecting materials and structures. Among these, ultrasonic testing stands out as the most prevalent method, …

Electrode Engineering For Enhanced Performance And Low-Cost Redox Flow Batteries, Abena Williams

All Dissertations

none

Progress In Selective Laser Sintering Ofmultifunctional Polymer Composites For Strain- And Self-Sensing Applications, Muhammad Umar Azam, Imane Belyamani, Andreas Schiffer, Shanmugam Kumar, Khalid Askar

All Works

Recent decades have witnessed significant advancements in additive manufacturing (AM) of polymer composites, leading to the development of material systems with intricate architecture and composition. Selective laser sintering (SLS), among various AM methods, offers numerous advantages such as high mechanical strength in printed parts, recyclability of unused powders, and the ability to print large batches without support structures. Moreover, SLS has remarkably succeeded in fabricating electrically conductive polymer composites (ECPCs) with exceptional functional performance which is attributed primarily to the formation of a segregated filler network along the powder particle boundaries. This review aims to delve into SLS for processing …

Vr Circuit Simulation With Advanced Visualization For Enhancing Comprehension In Electrical Engineering, Elliott Wolbach

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

As technology advances, the field of electrical and computer engineering continuously demands innovative tools and methodologies to facilitate effective learning and comprehension of fundamental concepts. Through a comprehensive literature review, it was discovered that there was a gap in the current research on using VR technology to effectively visualize and comprehend non-observable electrical characteristics of electronic circuits. This thesis explores the integration of Virtual Reality (VR) technology and real-time electronic circuit simulation with enhanced visualization of non-observable concepts such as voltage distribution and current flow within these circuits. The primary objective is to develop an immersive educational platform that makes …

Design And Optimization Of A Novel Monolithic Spring For High-Frequency Press-Pack Sic Fet Modules, Bogac Canbaz

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

Silicon Carbide (SiC) Field-Effect Transistor (FET) modules lead the way in power electronics, being superior in efficiency and robustness for high-frequency applications. The shift towards SiC from traditional silicon (Si)-based devices is driven by its superior thermal conductivity, higher electric field strength, and operational efficiency at elevated temperatures. These features are critical for the development of next-generation, grid-oriented power converters aimed at enhancing the reliability and sustainability of power systems. This research focuses on high-frequency press-pack (HFPP) SiC FET modules, addressing the primary challenge of miniaturizing SiC FET dies without compromising performance, through an innovative press-contact design essential for increased …

An Investigation Of Information Structures In Dna, Joel Mohrmann

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

The information-containing nature of the DNA molecule has been long known and observed. One technique for quantifying the relationships existing within the information contained in DNA sequences is an entity from information theory known as the average mutual information (AMI) profile. This investigation sought to use principally the AMI profile along with a few other metrics to explore the structure of the information contained in DNA sequences.

Treating DNA sequences as an information source, several computational methods were employed to model their information structure. Maximum likelihood and maximum a posteriori estimators were used to predict missing bases in DNA sequences. …

Surface Chemistry Of Femtosecond Laser Processed Surfaces, Graham Kaufman

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

Micromachining and surface functionalization with femtosecond lasers is a rapidly developing technology in the field of materials and interfacial sciences due to its flexibility towards materials, tunability in surface features, and prospects for scalability. Many interfacial applications have been shown to be enhanced with femtosecond laser-induced surface texturing including two-phase heat transfer, antimicrobial properties, electrochemical systems and more. However, without ideal surface chemistry, the enhancements cannot be optimized for a given application. Surfaces functionalized by femtosecond lasers tend to have transient surface chemistries when exposed to the atmosphere, changing important interfacial properties like the interaction of the solid surfaces and …

From Bits To Beds: Design And Implementation Of A Hotel Booking System A Coding Project, Alexa Gilman

University Honors College

This thesis presents a comprehensive hotel booking system designed and implemented to showcase the transition "From Bits to Beds". There are two main motivations behind this project: firstly, to provide users with a user-friendly and efficient platform for booking accommodations. Secondly, it serves as a great learning opportunity, providing hands-on practice with coding, collaboration with teammates, and exposure to real-world challenges. The system utilizes technologies such as JavaScript, Express.js, and HTML/CSS to offer features like browsing hotels, filtering options, user authentication, and booking management. The implementation of this project demonstrates a successful integration of backend and frontend components, ensuring reliability …

Keratin-Based Film: Waste To Bioplastic, Emma Bond

University Honors College

The solution to plastic lies in alternative materials, like bioplastics. One such possibility is keratin-based films. They are made from sources that are already deemed to be waste and that all regions of the world are abundant in. Manufacturing values a one-size-fits-all solution and keratin being plentiful worldwide fulfills that set standard. The films’ properties, which are important to the basic needs of a package, vary with different additives and the type of keratin used. α-keratin and β-keratin have different strengths and are found in nature in different sources. The resource focused on was chicken feathers, which produce more β-keratin …

Smart Manufacturing Of Cement: From Lab-Scale Simulation And Testing To Industry-Scale Deployment., Juan David Tabares Tamayo

Electronic Theses and Dissertations

Cement kilns are controlled by experienced process operators who follow experience-based industry guidelines using data collected and fundamental knowledge. The manufacturing process, which is equipped with sensors and equipment, transfers data/information to the operators to aid standardized decision-making operations. In contrast, companies have used such data to develop and implement digital solutions for predictive control systems; in effect, FLSmidth and Rockwell Automation. However, despite the availability of automated control systems and investigation in automation for process monitoring and optimization, opportunities to radically optimize cement manufacturing are still abundant and in need of implementation. Therefore, this research developed simulation models and …

Fly Ash Based Geopolymer: Water, Curing Temperature And, Cao Content Effects On Microstructure And Compressive Strength., Lujain Salem

Electronic Theses and Dissertations

Geopolymer, an emerging alternative to Portland cement-based concrete, relies on alumina and silica-rich precursors like fly ash for its formation. Geopolymerization is a chemical process that creates a three-dimensional polymer network by reacting with an alkaline activator. While fly ash's calcium oxide (CaO) content is crucial in its classification, it behaves differently in geopolymerization, where it competes with hydration. Therefore, a better understanding of the impact of CaO content in fly ash on geopolymerization is needed to effectively utilize fly ash. This study investigates the effects of CaO content, water, and curing temperature on geopolymerization. Using fly ash from a …

In-Training Explainability Frameworks To Make Black-Box Machine Learning Models More Explainable., Asuman Cagla Acun

Electronic Theses and Dissertations

Despite ongoing efforts to make black-box machine learning models more explainable, transparent, and trustworthy, there is growing advocacy for using only inherently interpretable models for high-stake decision-making. Post-hoc explanations have recently been criticized for learning surrogate models that may not accurately reflect the actual mechanisms of the original model and for adding computational burden at prediction time. We propose two novel explainability approaches to address these limitations: pre-hoc explainability and co-hoc explainability. These approaches integrate explanations derived from an inherently interpretable white-box model into the learning stage of the black-box model without compromising accuracy. Unlike post-hoc methods, our approach does …

The Role Of Voluntary Descending Control In Enhancing Motor Function Via Transcutaneous Spinal Cord Stimulation, Yoon Kim

McKelvey School of Engineering Graduate Student Theses & Dissertations

Spinal cord injury (SCI) is a life-changing event that causes lasting motor impairments. Transcutaneous spinal cord stimulation (tSCS), a non-invasive form of neuromodulation in which electrodes are placed on the skin and used to stimulate the spinal circuits via an electrical current, has demonstrated positive effects on motor function recovery in individuals who have had SCIs. However, the precise mechanism of how tSCS interacts with voluntary descending drive remains poorly understood. This study aims to investigate the role of voluntary descending control in influencing reflex responses triggered by tSCS.

Electromyography (EMG) recordings were performed in ten unimpaired individuals while they …

Building Services Engineering May/June 2024

Building Services Engineering

No abstract provided.

High Bandwidth Hybrid Current Sensor Readout Interface For Power Applications, Asma Mahar

Graduate Theses and Dissertations

High-density and power-efficient circuits have become realizable with the advent of wide bandgap semiconductor devices due to their high switching speed and lower conduction/switching losses. The operation of these circuits requires current information for protection, monitoring, and control. For the realization and a further boost in the efficiency of such power circuits, small size, non-invasive, high bandwidth current sensors with noise immunity, accuracy, and linearity are required. Various hybrid sensors have been reported to meet the requirements of emerging power circuits. A combination of a magneto resistor or Hall sensor and a coil is used to cover a wide frequency …

Physical And Stochiometric Controls On Nutrient Uptake And Ecosystem Respiration In Contrasting Sites, Jancoba K. Dorley

Civil Engineering ETDs

Meteorological, hydrological, and biogeochemical processes naturally control stream ecosystems. These processes define the frequency and distribution of precipitation and the supply and demand of solutes and particles to support aquatic food chains through space and time. Studies have also found that stream ecosystems are also controlled by anthropogenic activities, which occur on a much shorter timescale. These anthropogenic activities affect stream ecosystems' structure and function from local to planetary changes to the environment. It is essential for scientists and engineers to understand the relationships between naturally occurring processes and those created by human activities for a better interpretation of stream …

Design And Fabrication Of A Carbon Fiber Wheel For The Husker Motorsports Club, Benjamin Bashtovoi, Jordan Chapin, Michael Pineda, Caden Lind, Thomas Crum

Honors Program: Senior Projects (Public)

Every year, the Husker Motorsports team participates in a Formula SAE competition that challenges students to design and manufacture a Formula-style vehicle to compete against colleges from around the world. The Husker Motorsports club has sponsored this senior capstone project to improve the vehicle’s performance by reducing unsprung mass. Unsprung mass reduction has numerous benefits on vehicle dynamics, including improved acceleration, handling, and braking. To achieve these performance improvements, the team developed carbon-fiber composite wheels that weigh less than the current wheel solution and provide better rigidity. The team designed and modeled the wheel according to the 2023-2024 competition car …

Drag Reduction In Channel Flow Configurations For Laminar And Turbulent Flow Past Superhydrophobic Surfaces, Henry Louis Ems

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

In this work, we present friction drag reduction in minichannel laminar flow past superhydrophobic metallic surfaces. Femtosecond laser surface processing (FLSP), a one-step scalable method, was used to create permanent microscale and nanoscale structures on 316 stainless steel plates. The resulting superhydrophilic plates were covered by tall (215 μm) or short (27 μm) structures. The FLSP plates were then transitioned to superhydrophobic by evaporative deposition of a fluorinated silane, a low surface energy coating. Using purified water, the friction factor was obtained by measuring pressure drop along a minichannel with a rectangular cross section for flow rates corresponding …

Irt-Based Irrigation Scheduling And Dry Bean Crop Water Productivity Under Different Irrigation Scenarios In The Nebraska High Plains, Angie Gradiz

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Irrigation plays a critical role for crop production in western Nebraska of the United States, where crop evapotranspiration often exceeds in-season precipitation. This study investigated the impacts of different irrigation treatments on yield and key physiological parameters of dry edible beans grown in semi-arid western Nebraska during the 2022-2023 growing seasons. Seven irrigation levels (0%, 25%, 50%, 75%, 100%, 125%, 150%) of the fully irrigated treatment (FIT), were applied using a Variable Rate Irrigation (VRI) Linear-Move Sprinkler System. Additionally, an eighth treatment was scheduled based on measurement from infrared radiometry thermometers (IRT) to evaluate the performance of the two-source energy …

Diegetic Sonification For Low Vision Gamers, Jhané Dawes

Master's Theses

There are not many games designed for all players that provide accommodations for low vision users. This means that low vision users may not get to engage with the gaming community in the same way as their sighted peers. In this thesis, I explore how diegetic sonification can be used as a tool to support these low vision gamers in the typical gaming environment. I asked low vision players to engage with a prototype game level with two diegetic sonification techniques applied, without the use of their corrective lenses. I found that participants had more enjoyment and experienced less difficulty …

Cooperative And Bifunctional Adsorbent-Catalyst Materials For In-Situ Vocs Capture-Conversion, Sukanta K. Mondal, Peter Aina, Ali A. Rownaghi, Fateme Rezaei

Chemical and Biochemical Engineering Faculty Research & Creative Works

Volatile Organic Compounds (VOCs) Are Gases that Are Emitted into the Air from Products or Processes and Are Major Components of Air Pollution that Significantly Deteriorate Air Quality and Seriously Affect Human Health. Different Types of Metals, Metal Oxides, Mixed-Metal Oxides, Polymers, Activated Carbons, Zeolites, Metal-Organic Frameworks (MOFs) and Mixed-Matrixed Materials Have Been Developed and Used as Adsorbent or Catalyst for Diversified VOCs Detection, Removal, and Destruction. in This Comprehensive Review, We First Discuss the General Classification of VOCs Removal Materials and Processes and Outline the Historical Development of Bifunctional and Cooperative Adsorbent-Catalyst Materials for the Removal of VOCs from …