Engineering Commons^™

Controller Software: Evolution, Identification, And Implementation, Balaji Balasubramaniam

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

In the annals of automation history and advancement, one can find control technology is at the core. Modern-day controllers rely heavily on software capability to provide stability and improve the system's performance. In particular, drone flight controllers use autopilot control software to accomplish autonomous navigation from take-off to landing. However, we know very little about how the controller code modifications and its impact, particularly at the software level. No general framework has been developed to identify the control code changes and observe the real values of software control loops at the kernel layer.

In this thesis, we lay the foundation …

Cutting Mechanisms And Control Systems Required For Precision Cutting With An Autonomous Lettuce Harvester, Aidan V. Fischer

Master's Theses

43% of California’s vast land is consumed for agricultural production to feed the United States and other nations Lettuce production alone brought in over $3 billion in 2022 in California. Most of the lettuce today is still harvested by hand using large groups of seasonal laborers; however, this has become increasingly difficult with an immigrant labor shortage. The objective of this study was to design a low-cost autonomous lettuce harvester prototype and evaluate the performance of the harvester capable of harvesting romaine lettuce preciously on a raised bed.

The harvester is equipped with an electrohydraulic control system that is used …

Geochemical Evidence Of Drying During The 4.2 Ka Event In Sediment Cores From The Yucatán Peninsula, Mexico, Derek K. Gibson, Jonathan Obrist-Farner, Alex Correa-Metrio, Alejandra Rodriguez-Abaunza, Carlos Castañeda-Posadas

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Tropical hydroclimate variability during the Middle and Late Holocene was investigated using geochemical indicators of local-scale precipitation and evaporation preserved in sediment cores from two sites in the Mexican Yucatán Peninsula. Scanning X-Ray fluorescence spectroscopy data show generally decreasing precipitation trends during the Early and Middle Holocene. During the transition between the Middle and Late Holocene, geochemical evidence of reduced watershed erosion and increased evaporation indicate that a centennial-scale drying event impacted the region between 4.3 and 4.0 ka (kilo-anum; thousand years before present). These findings suggest that the 4.2 ka drying event, which has been previously recorded in Europe, …

A Strategic Insight Into The Market For Carbon Management Capacity, Mahelet G. Fikru, Ting Shen, Jennifer Brodmann, Hongyan Ma

Economics Faculty Research & Creative Works

This study presents the market for carbon management capacity via carbon capture, utilization, and storage technologies, identifying demand and supply forces, as well as clarifying the potential impact of market and non-market-based shocks on technology developers versus adopters. The paper addresses a prevailing gap in market analysis, introducing a microeconomic framework and unique dataset to identify key players, market forces, and policy incentives shaping the carbon capture, utilization, and storage landscape. The analysis equips industry stakeholders, policymakers, and investors with valuable insights regarding (1) leaders in the design, development, and manufacture of carbon capture, utilization, and storage technologies (supply), (2) …

Populations Digitally Excluded From Education: Issues, Factors, Contributions And Actions For Policy, Practice And Research In A Post-Pandemic Era, Don Passey, Jean Gabin Ntebutse, Manal Yazbak Abu Ahmad, Janet Cochrane, Simon Collin, Asmaa Ganayem, Elizabeth Langran, Sadaqat Mulla, Ma. Mercedes T. Rodrigo, Toshinori Saito, Miri Shonfeld, Saunand Somasi

Department of Information Systems & Computer Science Faculty Publications

This conceptual paper draws on a wide range of research and policy literature, providing a contemporary view of issues, factors and practices that affect education for digitally excluded populations. Concern for how education for digitally excluded populations can be supported is focal to this paper, with different sections offering key related perspectives. From an analysis of issues, factors and practices, actions for policy, practice and research are identified. Given a key finding that power issues can have major effects on plans, implementation processes and outcomes when addressing needs of education for digitally excluded populations, the paper concludes by offering frameworks …

Primary And Secondary Resonances Of Fringe Effect Electrostatically Actuated Mems Cantilever Resonators, Miguel Armando Martinez

Theses and Dissertations

The nonlinear dynamics of micro-electromechanical system (MEMS) cantilever resonators actuated by the fringe field at parametric and primary resonances are studied. Three models are used based on different descriptions of the system capacitance. In the fringe and capacitance models, the electrostatic force due to the parallel-plate capacitance is neglected due to a hole in the ground plate (removes overlapping area). The SolidWorks model is based on numerical capacitance simulations performed on SolidWorks using EMS. All three models that approximate the fringe field capacitance are compared with one another. The Method of Multiple Scales (MMS) and Reduced Order Model (ROM) up …

Study Of Temperature Effects Of Glucose And Microwave Dielectric Dispersion Model, Ethan Grant Boone

Theses and Dissertations

In this study, the temperature effect of dielectric properties in various aqueous solutions containing glucose are examined. A design for a new testing chamber is introduced to provide improved conditions for testing to ensure accurate and precise measurements. A N-SMA Adaptor is used when obtaining dielectric characteristics of glucose solutions ranging 100-300mg/dl. Dielectric parameters are obtained adopting a modified Debye dispersion model. MATLAB is used to confirm coaxial dimensions are suitable fabrication designs using fixed dielectric parameters of air and water. Simulations and design models were implemented utilizing ANSYS High Frequency Structure Simulator and 3-D Modeler software to develop the …

Resonances Of Electrostatically Actuated Non-Uniform Mems Cantilever Resonator Of Constant Width And Linearly Varying Thickness, Rigoberto Flores

Theses and Dissertations

In this investigation the behavior of an electrostatically actuated non-uniform microelectromechanical (MEMS) cantilever resonator of constant width and linearly varying thickness is investigated. The cantilever resonator vibrates using soft AC voltage at near half the first natural frequency of the cantilever and near the first natural frequency of the cantilever, known as primary and parametric resonances, respectively. Bifurcation diagrams for the amplitude-frequency and amplitude-voltage response are obtained for both resonances. Two methods are used in this investigation, namely the Method of Multiple Scales (MMS) and Reduced Order Model (ROM) using up to 6 modes of vibration.

These methods are used …

Thermal Conductivity Characterization Of High Oleic Vegetable Oils Based Hybrid Nanofluids Formulated Using Gnp, Tio2, Mos2, Al2o3 Nanoparticles For Mql Machining, Anthony Chukwujekwu Okafor, Tobechukwu Kingsley Abor, Saidanvar Esanjonovich Valiev, Ignatius Echezona Ekengwu, Abiodun Saka, Monday Uchenna Okoronkwo

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper presents the results of thermal conductivity characterization of six high oleic soybean oil (HOSO) and four high oleic canola oil (HOCO)-based hybrid nanofluids formulated with four types of nanoparticles (Graphene nanoplatelet (xGnP), TiO2, MoS2, and Al2O3) at nanoparticles wt.% concentration from 1 % to 7 % in 1 % increment using the two-step method for use in MQL machining of difficult-to-cut metals. Thermal conductivity of the formulated hybrid nanofluids were measured using Thermtest Transient Hot Wire Liquid Thermal Conductivity Meter at temperatures from 25 °C to 75 °C in increment of 10 °C. Obtained results showed that thermal …

Sustainable Poultry Farming Practices: A Critical Review Of Current Strategies And Future Prospects, Ramesh Bahadur Bist, Keshav Bist, Sandesh Poudel, Deepak Subedi, Xiao Yang, Bidur Paneru, Sudhagar Mani, Dongyi Wang, Lilong Chai

Biological and Agricultural Engineering Faculty Publications and Presentations

As global demand for poultry products, environmental sustainability, and health consciousness rises with time, the poultry industry faces both substantial challenges and new opportunities. Therefore, this review paper provides a comprehensive overview of sustainable poultry farming, focusing on integrating genetic improvements, alternative feed, precision technologies, waste management, and biotechnological innovations. Together, these strategies aim to minimize ecological footprints, uphold ethical standards, improve economic feasibility, and enhance industry resilience. In addition, this review paper explores various sustainable strategies, including eco-conscious organic farming practices and innovative feed sources like insect-based proteins, single-cell proteins, algal supplements, and food waste utilization. …

Compact Solar-Powered Plasma Water Generator: Enhanced Germination Of Aged Seed With The Corona Dielectric Barrier Discharger, Yiting Xiao, Yang Tian, Haizheng Xiong, Ainong Shi, Jun Zhu

Biological and Agricultural Engineering Faculty Publications and Presentations

Seed aging adversely affects agricultural productivity by reducing germination rates and seedling vigor, leading to significant costs for seed banks and companies due to the need for frequent seed renewals. This study demonstrated the use of plasma-activated water (PAW), generated by a solar-powered corona dielectric barrier discharger, to enhance germination rates of spinach seeds that had been stored at 4 °C for 23 years. Treating seeds with PAW at 17 kV for 15 min improved germination (by 135%) and seedling growth compared to untreated seeds. Through detailed analysis, beneficial PAW properties for seed development were identified, and a molecular mechanism …

Physicochemical Property Effects On Immune Modulating Polymeric Nanoparticles: Potential Applications In Spinal Cord Injury, Daniel J. Kolpek, Jaechang Kim, Hisham Mohammed, John C. Gensel, Jonghyuck Park

Markey Cancer Center Faculty Publications

Nanoparticles (NPs) offer promising potential as therapeutic agents for inflammation-related diseases, owing to their capabilities in drug delivery and immune modulation. In preclinical studies focusing on spinal cord injury (SCI), polymeric NPs have demonstrated the ability to reprogram innate immune cells. This reprogramming results in redirecting immune cells away from the injury site, downregulating pro-inflammatory signaling, and promoting a regenerative environment post-injury. However, to fully understand the mechanisms driving these effects and maximize therapeutic efficacy, it is crucial to assess NP interactions with innate immune cells. This review examines how the physicochemical properties of polymeric NPs influence their modulation of …

An Analysis Of Security Risks Posed By Text-Based Generative Ai And Corporate Security Weaknesses Leading To Data Leaks, Tashya Rakshana Byreddy

Electronic Theses, Projects, and Dissertations

ABSTRACT

Generative AI (GenAI) has become a fundamental part of modern life, influencing how we work, learn, and interact with technology. This project focuses specifically on text-based GenAI, which is widely used for tasks such as information gathering, code improvement, and content creation. Despite its benefits, it presents significant security risks that are often underestimated by users. This project investigates these risks and the corporate security gaps that lead to unintentional data leaks. The project also provides a brief overview of Large Language Models (LLMs), which are based on the deep learning technique known as Transformer architecture, used for performing …

Growing Industry-University Partnerships: Virtual Workshop On Industry Sponsored Research, Mark Stone, Santosh K. Pitla

Department of Agricultural and Biological Systems Engineering: Presentations and White Papers

The Department of Biological Systems Engineering (BSE) at the University of Nebraska-Lincoln (UNL) hosted a virtual workshop on developing capacity for industry-sponsored research (ISR). This dynamic event brought together faculty, researchers, industry leaders, and students to explore innovative strategies for advancing ISR.

The workshop addressed four key themes: (1) fostering sustainable industry-academic partnerships; (2) tackling intellectual property (IP) challenges; (3) building institutional and individual capacity for ISR, and (4) empowering students as critical contributors to industry research. Through expert-led presentations, an engaging panel discussion, and interactive brainstorming sessions, participants identified actionable steps and articulated a vision for the future of …

Effects Of Concrete With The Implementation Of Spent Coffee Grounds, Nathan Limon

Construction Management

During this study, compression tests were performed on three different concrete mix designs to evaluate the effects of spent coffee grounds as an admixture. The initial mix design was the control mix, composed of a general concrete mix design containing aggregate, cement, and water. The second mixture utilized was high strength concrete; this included aggregate, cement, and water, fly ash. The third mixture tested consisted of aggregate, cement, water, and spent coffee grounds. The purpose of evaluating these three different mixtures is to see whether spent coffee grounds can be implemented into concrete without compromising the compressive strength. Substituting 15% …

Striking A Balance: Market Shock & Responses In Automotive Components Manufacturing, Emma Lane Mcgahey

All Theses

This thesis examines the effects of extreme market shocks on supply chain dynamics within the automotive industry. Through an analysis of demand data from an automotive manufacturer to its component suppliers (January 2018 to May 2024), the study investigates the relationship between market shocks and supply chain responses, providing insights into how auto components inventory management handles downstream responses to market shocks. With supporting public data—from FRED, BLS, and the U.S. Census Bureau resources—we explore two primary relationships: the impact of market shocks on the Average Standard Deviation of Demand (SDO) and the effect of demand variability on expedited pricing …

Higher Order Bessel Beams Integrated In Time (Hobbit) With Engineered Light Frequencies And Applications In Computational Imaging, Tyler Cramer

All Theses

This thesis presents an adaptive optical system which leverages the frequency shifts from an acousto-optic deflector (AOD) form an array of uniformly spaced frequency diverse beamlets. These beamlets are then spatially transformed (wrapped) into a circular array forming a non-diffracting ring with an unprecedented orbital angular momentum (OAM) mode switching rate of 50Mhz with an OAM range of ±64. Along with frequency diversity, the non-diffracting range of the beams are analyzed 6 Rayleigh ranges of an equivalently sized gaussian beam. Inherent in the frequencies superposed on the AOD are associated relative phases which can be controlled to form sets of …

Peer Collaborative Networks In Undergraduate Computing Classrooms, Noah T. Ravetch

Master's Theses

Peers are an invaluable resource for students at undergraduate universities. Many factors can impact how students form connections, some of which are tied to the students’ identities. While social networks have been studied in the context of universities, little research has been done specifically about peer collaboration and even less in the context of computer science classes. Our research aims to gain an understanding of how peer networks form in computing classes and the effect of being involved in one on students’ academic performances. We collected survey data (n = 139) about students’ peer collaborative behaviors in computer science classes. …

Performance Of Multi-Composite Materials With Corrugated And Cell Geometries Under Low-Velocity Impact, Lukas S. Kolbl

Master's Theses

Composite structures have demonstrated great potential to improve mechanical performance in various applications, including ballistics protection. This study demonstrates that the integration of geometrically optimized composites into core-face sheet assemblies provide great impact resistance. The research investigated the performance of two composite manufacturing methods under low-velocity impact through residual strength and damage comparisons. Corrugated core composites were produced with traditional manufacturing methods, namely compression molding, using twelve stacking sequences. These stacking sequences were chosen to represent four laminate groups, where a unique fiber orientation scheme was employed across three laminate thicknesses (6, 8, and 12 layers). In contrast, honeycomb and …

Finite Element Analysis And Verification Of Transverse Mechanical Properties Of Generally Cylindrical Orthotropic Constitutive Modeling Of 3-Phase Nanocomposite Unit Cell, Christopher J. Hawkins

Master's Theses

Fiber-reinforced composites are increasingly popular due to their specific strength and stiffness, making them ideal for high-performance applications. However, these materials primarily exhibit superior properties in-plane, while their out-of-plane characteristics remain comparatively weaker. Previous research has shown that the most effective method to enhance out-of-plane properties involves the incorporation of carbon nanotubes. Experimental tests have demonstrated significant improvements in properties such as tension, flexural, short beam shear, and fracture toughness. Alongside these experimental studies, analytical equations have been developed to predict the behavior of these composites under various loading conditions, including tension, bending, shear, and fracture. Existing models primarily address …

Bonsai Merkle Tree Streams: Bulk Memory Verification Unit For Trusted Program Verification System, Richard J. Rios

Master's Theses

Today, all modern computing systems are undoubtedly vulnerable to numerous types of attacks that could be targeted toward any layer of the system from dedicated hardware to highly abstracted software. Unfortunately, many devices and systems naturally contain inadequately protected components or software modules that un- dermine their security as a whole. Additionally, security is heavily variable system to system, and has a huge dependence on adequate implementation and ongoing support from device and software manufacturers. To address these various security issues in a very general way, TrustGuard, a containment security system utilizing an external device called the Sentry that would …

Photophoretic Optical Particle Trapping Improvements Using Beam Reflection, Ian A. Garcia, Xiaomin Jin Phd., Kun Hua Phd.

Master's Theses

Current research has shown that photophoretic optical trapping (POT) is a promising method for creating true three-dimensional holograms. A landmark study by Smalley et. al. at BYU was able to generate a full hologram within a 2 cm edge cube with remarkable success. However, a key drawback to this method is its poor ability to hold trapped particles within the focal point of the laser for an extended period of time. An investigation from our group presented at SPIE Photonics West 2023 sought to improve these results by varying the focal length of the trapping and the wavelength of the …

Investigating The Conversion Of A Signalized Intersection To A Turbo Roundabout, Vyshnavi P. Shetty

Master's Theses

Turbo roundabouts are multilane roundabouts that utilize a spiral design with raised lane dividers to guide traffic flow effectively. While they have seen widespread use in Europe, California is the second state in the US (after Florida) to have installed a turbo roundabout. Turbo roundabouts separate the ingress and circulating lanes. The concept was first proposed and implemented in the Netherlands to address safety concerns and improve traffic flow efficiency on conventional multilane roundabouts.

This research evaluates the first-ever turbo roundabout in California and compares its safety and operational performance with the previously existing 4-legged signalized intersection. The research team …

An Investigation Into The Use Of Amateur Astronomy Equipment For Optical Orbit Determination Using A Mobile Telescope Platform, Johan C. Govaars

Master's Theses

The process of optical orbit determination has long been in the domain of large organizations and stationary observatories with highly specialized scientific equipment. This thesis seeks to determine not only if satellites can be captured regularly using purely commercial-off-the-shelf (COTS) equipment, but also if initial orbit determinations can be made using that data. Moreover, the use of a mobile telescope platform allows users to circumvent the restrictions of fixed observatories such as low horizon viewing restrictions or existing light pollution.

A completely COTS setup was utilized that included an 8-inch Celestron NextStar 8SE telescope with an f/6.3 focal reducer and …

A Novel Interpretation Of Average Run Length For Assessing The Performance Of Control Charts, Gonçalo Sousa

Masters Theses

The Average Run Length (ARL) is a performance measure of Control Charts widely used within Statistical Process Control. In this study we propose a new approach for the computation of the ARL that is based on a novel interpretation of out-of-control signals produced by a Control Chart. Specifically, out-of-control signals used to calculate traditional ARLs may correspond to Type I errors and may not reflect a Control Chart’s true performance. To compensate for this issue, for Shewhart and EWMA charts, constraints are applied to the calculation of ARLs so that only out-of-control signals that occur when the corresponding statistic is …

Investigating Challenges Of Converting Cad Models To Game Ready Assets, Vathsa Pawar

All Theses

This thesis explores the challenges associated with converting detailed CAD models into game-ready assets optimized for use in virtual reality (VR) environments using game engines, focusing on enhancing using mechanical engineering models. The primary goal is to establish a toolchain that allows the integration of CAD models into game engines for immersive applications, enabling engineers and stakeholders to interact with 3D models in a synthetic environment. The study employs several test cases ranging from simple door models to complex automotive vehicle prototypes, elaborating the process of exporting CAD models through intermediate formats (such as STEP, STL, GLB) using tools like …

Assessing The Potential For Photosynthetic Degradation Of Per- And Polyfluoroalkyl Substances, Marlow Thomas

All Theses

PFAS is a prevalent groundwater contaminant. It has been known to cause many health issues for humans and animals including cancer and several diseases. A main problem faced with PFAS is contamination in groundwater. Remediation strategies have been and continue to be researched to try to mitigate this issue. Current treatment strategies to mitigate PFAS include the use of granular activated carbon, ion exchange, chemical oxidation, and many hybrid treatments. There has not been one treatment technology to date that has prevailed as the best due to monetary and time constraints.

The main intention behind this research is to examine …

Optimizing Compression Efficiency With Adaptive Quantization Bit Depths, Carson Sisk

All Theses

Large-scale scientific instruments and applications generate massive amounts of data, lead- ing to significant challenges in data transfer and storage for analysis. This constitutes a major

bottleneck to workflow efficiency and scientific throughput. Lossy compression offers a solution to

these storage challenges in increasingly complex systems and services. Error-bounded lossy compression allows users to limit the error introduced during the compression process according to a user-defined metric and achieves significantly higher compression ratios than lossless compression for floating-point data. However, certain data types and compression configurations hinder the attainment of large compression ratios. To address the need for improved compression …

Life Cycle Assessment Approach For Energy Usage In Animal Rendering Plants, Abel Binoy Mathew

All Theses

The animal rendering industry plays a crucial role in transforming waste products from livestock production and meat processing facilities into valuable and economically beneficial products, promoting both resource efficiency and sustainability. This study uses a life cycle assessment (LCA) approach to evaluate energy usage and greenhouse gas emissions in animal rendering plants, focusing on electricity and natural gas as the main energy inputs for plant operation. This research examines three distinct rendering facilities, each processing different raw materials, to quantify the environmental impacts of rendering operations. Site visits, data collection, and real-time monitoring were used to capture energy use across …

Pressureless Sintering Of Sic - Oxide Multiphase Ceramics For Protective Coating Applications, Reilly Boros

All Theses

For hydrogen-fueled combustion, there exists a demand to improve coating materials that are capable of protecting SiC_f/SiC CMC turbine material. Promising coating materials must be able to shield from harsh oxidation while working at extremely high temperatures. The work presented in this thesis aims to expand the understanding of two promising material systems for integrated environmental barrier coating (EBC) – thermal barrier coatings (TBC) by fabricating bulk composite ceramic samples and performing characterization to further understand their sintering behaviors. In this study, a processing procedure to consistently produce dense composite ceramics of PDC SiC – Y₂Si …