Engineering Commons^™

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 …

Future Of Process Safety: Insights, Approaches, And Potential Developments, Hossein Abedsoltan, Amirhesam Abedsoltan, Zeinab Zoghi

Chemical and Biochemical Engineering Faculty Research & Creative Works

This review explores the evolving landscape of process safety, emphasizing the integration of digitalization and advanced technologies. It assesses the role of the industrial Internet of Things, artificial intelligence, and machine learning (ML) in enhancing safety protocols. The paper examines predictive analytics, sensor technology advancements, and digital twins' contributions to safety optimization. It also discusses the future perspectives of risk management approaches, including proactive safety management systems, quantitative risk assessment techniques, and human reliability analysis. This comprehensive analysis provides insights into future developments and challenges in process safety.

Spatial Hearing In Simulated Reverberant Classroom Environments, Gabriel Seth Evan Weeldreyer

Durham School of Architectural Engineering and Construction: Dissertations, Theses, and Student Research

Spatial hearing provides access to auditory spatial cues that promote speech perception in noisy listening situations. However, reverberation degrades auditory spatial cues and limits listeners’ ability to utilize these cues for segregating target speech from competing babble. Hence, spatial unmasking—an intelligibility benefit from a spatial separation between a target and masker—is reduced in reverberant environments as compared to free field. This work tests the hypothesis that interaural decorrelation, the result of increasing reverberation, will broaden the perceived auditory source width with a cascading effect of reduced auditory spatial acuity and subsequently poorer spatial unmasking. To understand the perceptual consequences of …

Next-Generation Crop Monitoring Technologies: Case Studies About Edge Image Processing For Crop Monitoring And Soil Water Property Modeling Via Above-Ground Sensors, Nipuna Chamara

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

Artificial Intelligence (AI) has advanced rapidly in the past two decades. Internet of Things (IoT) technology has advanced rapidly during the last decade. Merging these two technologies has immense potential in several industries, including agriculture.

We have identified several research gaps in utilizing IoT technology in agriculture. One problem was the digital divide between rural, unconnected, or limited connected areas and urban areas for utilizing images for decision-making, which has advanced with the growth of AI. Another area for improvement was the farmers' demotivation to use in-situ soil moisture sensors for irrigation decision-making due to inherited installation difficulties. As Nebraska …

Mechanical Engineering Capstone: A Reflection On The Design And Prototyping Of A Portable Water Heating System, Timothy Goldsmith

Honors Program: Senior Projects (Public)

This thesis includes several documents from a Mechanical Engineering Capstone course. These include project postmortem reports written at the conclusion of each term. These reports summarize the designing and prototyping of a portable water heating system. Additionally, this thesis includes written feedback on the final presentations for six other senior design teams. In these documents, presentations and projects are evaluated and encouragement and feedback are provided for the teams. The final component of this thesis is an essay reflecting on the different leadership roles assumed during the capstone course.

Orms And Database Design, Kalim Dumas

Honors Program: Senior Projects (Public)

This thesis explores the relationship between database design and Object-Relational Mapping (ORM) design, investigating how they have evolved together and influenced each other. It addresses a theoretical discussion, a practical implementation, and some observations regarding integrating an ORM into my Senior Design project. My Senior Design project was originally built without the intention of implementing an ORM.

There are a lot of complicated discrepancies between Relational Databases (RDBs) and Object-Oriented Programming Languages (OOPLs), called the Impedance Mismatch Problem. The fact that they are both foundational pillars in software engineering means that one cannot simply change to match the other. ORMs …

Determining The Impacts Of Corn Silage Mixing Ratios On Hydrogen Production From Beef Cattle Manure, Katya Faber-Quimby

Honors Program: Senior Projects (Public)

With global warming becoming an increasingly serious threat and a growing population requiring additional energy resources, interest in the production of clean energy from the agricultural sector has surged in popularity. Biohydrogen, also known as green hydrogen, is H₂ that has been produced using renewable energy, such as from agricultural byproducts or waste materials. It presents a promising alternative to nonrenewable resources due to its high potential for energy storage and lack of carbon emissions when used. Cattle manure has been explored as a resource for the production of biohydrogen. Selecting for hydrogen-producing microbes in the manure serves the …

The Analysis Of Mechanical Exfoliation Of Graphene For Various Fabrication And Automation Techniques, Lance Yarbrough

Mechanical Engineering Undergraduate Honors Theses

Mechanical Exfoliation of Graphene is an often-overlooked portion of the fabrication of quantum devices, and to create more devices quickly, optimizing this process to generate better flakes is critical. In addition, it would be valuable to simulate test pulls quickly, to gain insight on flake quality of various materials and exfoliation conditions. Physical pulls of graphene at various temperatures, pull forces, and pull repetitions were analyzed and compared to the results of ANSYS simulations, solved for similar results. Using ANSYS’ ability to predict trends in exfoliations, flake thickness and coverage using stress and deflection analyses were investigated. Generally, both strongly …

Large Eddy Simulation Of Fluid Mixing In Migadome Facility For The Astfe Nuclear Thermal Hydraulics Cfd Competition, Kolten Strauss

Mechanical Engineering Undergraduate Honors Theses

This paper is a documentation of a submission to the First Annual ASTFE Nuclear Thermal Hydraulics Computational Fluid Dynamics (CFD) Competition [1]. To validate simulations of turbulent mixing in buoyancy-driven flows, an air and argon test case was set up inside the University of Michigan’s MiGaDome mixing vessel. This submission to the competition used a polyhedral mesh of about two and a half hundred thousand cells, a Large Eddy Simulation (LES) of the MiGaDome, and the Wall-Adapting Local Eddy-viscosity (WALE) subgrid approximation model. The competition included a factor considering the energy cost of our simulations, so it was decided to …

Experimental And Numerical Investigation Of Air-Cooled Heat Sinks, Ethan Weems

Mechanical Engineering Undergraduate Honors Theses

Lightweight and affordable cooling capabilities are critical as the physical scale of electronics continues to decrease. Air-cooled heat sinks that dissipate heat from electronic components to the surrounding air are excellent candidates to fill this role. While plate-fin and pin-fin heat sinks have been implemented extensively for electronic cooling, recent advances in additive manufacturing enable the fabrication of more complex structures. In this undergraduate Honors thesis, a means by which to generate novel heat sink geometries is presented. To that end, an experimental characterization facility is developed to evaluate existing traditional heat sinks. The heat transfer performance of the heat …

A Review And Analysis Of General Aviation Instructional Accidents, Sydney Sommers

Mechanical Engineering Undergraduate Honors Theses

General aviation student pilot accidents represent a substantial portion of all aviation accidents in the United States. Almost 50% of general aviation accidents involve student pilots. Analyzing historical accident reports is the most common approach to studying accident causation. The National Transportation Safety Board (NTSB) investigates all civil aviation accidents in the US. Using the NTSB data, I analyzed general aviation student pilot accidents in the US between 2013 and 2022. Results indicate that most accidents take place in California and Florida and can be attributed to student pilots between 18 and 65 years of age. Alaska and Maine had …

Comparative Analysis Of Command Protocols For Cubesat Data Handling Systems, Roman Dowling

Mechanical Engineering Undergraduate Honors Theses

Researchers at the University of Arkansas developed ARKSAT-1, a cubic satellite with the purpose of employing an LED with a tracking system to perform spectroscopic measurements of the atmosphere.

The control board of the satellite contained several microcontrollers which worked in concert to collect and manage data. Discussed in this report are the software programs developed for the microcontrollers, dual Arduino MKRZeros, utilized as data repositories and for control of satellite peripherals. The programs discussed in this project include an original existing command-response protocol and an improved batch-command protocol, each with its accompanying data handling and storage system. These programs …

A Study Of Varying Dielectric Constant And Thickness Of Dielectric Barrier Discharge Devices And Their Subsequent Plasma Actuation, Sharon Kardasz

Mechanical Engineering Undergraduate Honors Theses

The principles of air-breathing ion propulsion are relatively unestablished in the aerodynamic realm as traditional forms of combustion for propulsion systems have remained in use. However, due to increasing environmental, economic, and efficiency concerns of traditional combustion, interests in innovative propulsion methodologies, such as electric propulsion, are emerging. A primary technology of interest for use of ion propulsion is the Dielectric Barrier Discharge Device (DBD). Preliminary research conducted at the University of Arkansas has determined the most favorable DBD geometry. This work will continue the preliminary research to decipher the most favorable DBD configuration by varying dielectric thickness and dielectric …

High Performance Silicon Carbide Based Converters For Powertrain Electrification, Nan Lin

Graduate Theses and Dissertations

With the increasing concern towards environment protection, electric vehicles (EVs) and hybrid electric vehicles (HEVs) have become popular in recent years. They not only help reduce carbon emissions, but also come with other benefits such higher efficiency and better user experience. Many countries and vehicle manufactures have made their plans to keep up with this trend in vehicle electrification. Powertrain is an assembly of components in a vehicle that pushes it forward. As for EVs and HEVs, their powertrains are composed of one or more power electronics converters, which are significant to the system. Silicon carbide MOSFETs have shown superior …

Hardware Trojan Detection Utilizing Graph Neural Networks And Structural Checking, Hunter Nauman

Graduate Theses and Dissertations

The integrated circuit (IC) industry has experienced exponential growth, particularly in the complexity and scale of hardware designs. To sustain this growth, faster development cycles and cost-effective solutions have been the focus for many companies. One strategy to maintain this growth is through the incorporation of third-party intellectual property (IP) into the IC design process. Outsourcing the production of sub-components reduces development time and enables faster time-to-market, however, this approach also introduces the threat of Hardware Trojans. Hardware Trojans, defined as any malicious modification or addition to an IC, pose significant security risks due to their small size, low activation …

Design And Implementation Of High-Frequency Dc-Dc Converters For Ev Applications, Rahul Biswash

Graduate Theses and Dissertations

The power electronics industry has been revolutionized by introducing wide bandgap semiconductor devices, such as Silicon Carbide (SiC) and Gallium Nitride (GaN). Due to their high frequency, high temperature, and high voltage operating capabilities, wide bandgap devices boast significant improvements in power density, efficiency, and reliability, as evidenced by their ability to decrease the size of power converters by operating at higher frequencies, temperatures and voltages, use of smaller and less passive components, such as transformers, inductors and capacitors, which makes power converters more compact and light-weight, ideal for space and weight-constrained applications, and compatibility with a wide range of …

Methodologies For Optimization And Surface Heat Flux Estimation For Hybrid Thermal Protection Systems, Syed Arafun Nabi

Theses and Dissertations

Thermal protection system (TPS) plays a pivotal role in safeguarding space vehicles from extreme aerothermal heating during atmospheric entry. To ensure effective thermal management, Hybrid Thermal Protection seamlessly integrating both active and passive TPS is an innovative solution. The passive TPS consists of an insulative layer on vehicle skin to counteract the aerothermal heat. Although a thicker layer enhances insulation, a trade-off arises between the thickness of the passive layer and the spacecraft’s weight. Beneath the passive TPS layer lies the active TPS functioning as a heat exchanger where the vehicle fuel liquid is considered as coolant. The effectiveness of …

An Investigation Into In-Flight Loss Of Control Accidents Due To Horizontal Stabilizer Changes On The Piper Cherokee, Connor John Geran

Theses and Dissertations

Loss of Control (LOC) while in-flight in General Aviation (GA) has been the subject of intense research by academic institutions and regulatory agencies in recent years [4] [9] [11] [19] [20] [21]. This interest is primarily due to a disproportionate number of all aircraft accidents occurring within the GA category of flight, with 94% of accidents in 2022 occurring within GA, caused primarily by pilot LOC, with 42% of accidents having LOC as the listed cause. Research into this subject at FIT yielded the results that many common GA aircraft tend to experience a strong pitch up response after undergoing …

Cosmic Object Space Management Operations System (C.O.S.M.O.S.), Riah Ivy, Tyler Bumpus, Gabriel Soter

Senior Design Project For Engineers

In the expansive realm of outer space, humanity has ventured into new territories, yet this progress is accompanied by challenges. Among the most significant challenges confronting space exploration today is the growing amount of space debris within low earth orbit. Satellites, spent rocket stages, and assorted fragments orbiting Earth present a considerable hazard to spacecraft and astronauts, and this issue is steadily worsening. For years, the task of remedying this orbital congestion has remained formidable and unresolved. This design provides a novel and innovative solution to this growing problem.

Effects Of Ferrite And Graphite Phases On Scratch Characteristics Of Nodular Cast Iron, Zhitong Xu, Ming Liu, Chenghui Gao, Fuqian Yang

Chemical and Materials Engineering Faculty Publications

In this work, we conduct micro-scratch tests of nodular cast iron with Vickers indenter under constant normal load and investigate the effects of individual phases (i.e., ferrite and graphite phases) on the scratch charac- teristics of nodular cast iron. Using a bimodal Gaussian model to fit the experimental data of penetration depth, residual depth, elastic recovery rate, and scratch hardness, we calculate the contribution percentages of indi- vidual phases to scratch variables. The scratch variables are independent of the scratch speed used in this work, while the penetration depth increases linearly with increasing the normal load. There exists a large …

A Mechanical Model For Stress Relaxation Of Polylactic Acid/Thermoplastic Polyurethane Blends, Yi-Sheng Jhao, Hao Ouyang, Chien-Chao Huang, Fuqian Yang, Sanboh Lee

Chemical and Materials Engineering Faculty Publications

Polylactic acid (PLA) is considered a promising biodegradable polymer alternative. Due to its high brittleness, composite materials made by melt blending thermoplastic polyurethane (TPU) with PLA can enhance the toughness of PLA. To understand the forced aging caused by stress relaxation in polymer materials, this study explains the stress relaxation experiments of PLA/TPU blends with different mass ratios under applied strain through mechanical model simulations. The Kelvin representation of the standard linear solid model (SLSM) is used to analyze the stress relaxation data of TPU/PLA blends, successfully explaining that the Young’s moduli (E1 and E2) of springs decrease with increasing …

Bcl2 Mediated Targeted Drug Delivery For The Treatment Of Kidney Fibrosis And Stomach Cancer, Humayra Afrin

Open Access Theses & Dissertations

Apoptosis, the programmed death of cells, is primarily regulated by a delicate balance between pro-apoptotic and anti-apoptotic signals. The Bcl-2 (B-cell lymphoma 2) family of proteins acts as anti-apoptotic agents, promoting cell survival. Dysregulation of these proteins is a common occurrence in conditions such as cancer and fibrosis, where overexpression of anti-apoptotic members can foster tumor cell survival and fibroblast activation. In this study, our aim was to explore the therapeutic potential of Bcl-2 inhibitors, both as a small molecule (specifically Navitoclax (Navi)), inhibitor and as Bcl-2 siRNA, for targeted treatment. Intravenous administration of Navi often leads to thrombocytopenia, necessitating …