Engineering Commons^™

Enhancing Water Sustainability In North Africa: Literature Review And Synthesis Of Current Knowledge Gaps In Sudan, Osman M. A. Adam

Department of Agricultural and Biological Systems Engineering: Masters Project Reports

This study delves into the critical role of groundwater in addressing global water challenges, with a focus on the Nubian Sandstone Aquifer System (NSAS) in north Africa. Groundwater constitutes a source of potable water, irrigation, and industrial use, especially in arid regions where surface water is limited. We analyzed the status of water quantity, withdrawals, recharge, and geological characteristics in the NSAS, specifically in Sudan, Egypt, and Libya. Though the NSAS is largely an untapped resource, water withdrawals from the NSAS in Egypt, Sudan, and Libya are projected to increase substantially from 2000 to 2100 due to population growth, with …

Minimizing Take Of Threatened Rattlesnakes And Optimizing Project Review In Se Nebraska, Shaun Dunn, Dan Fogell, Colleen Rothe-Groleau

Nebraska Department of Transportation: Research Reports

The western massasauga (Sistrurus tergeminus) and the timber rattlesnake (Crotalus horridus) are protected under Nebraska Statute 37-801-811 and listed as threatened species. These species occur in the right-of-way (ROW) along several roads in Jefferson, Gage, Pawnee, and Richardson Counties which necessitates the need for added Environmental Review (ER) from Nebraska Department of Transportation (NDOT) staff and onsite surveys prior and during maintenance and construction to roadways. This project sought to minimize ER time, staff time, and increase the knowledge of these species in southeast Nebraska by:

1. Identifying precise locations of western massasauga brumation sites;
2. Mapping travel …

Investigation Of Conductive Die-Top Thermal Capacitors During Short Circuit Operation Of Silicon Carbide Devices, Youssef Abotaleb

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

Silicon carbide (SiC) power devices have garnered significant attention in recent years due to their superior thermal and electrical properties compared to traditional silicon devices. However, SiC power devices suffer from severe reliability issues arising from their mechanical properties. This is because the Young's modulus of SiC is about three times larger than that of silicon, which correspondingly raises the mechanical stresses acting on the bonding structure, often leading to device failure under power shock events.

Traditional packaging materials and designs tend to constrain SiC performance, as hot-spot temperature resulting from a power shock is one of the key factors …

Using Symbolic Execution To Analyze The Hardware Tcp Protocol, Nianhang Hu

School of Computing: Dissertations, Theses, and Student Research

As the demand for high performance and flexible networking capabilities increases, the shift from software to hardware implementations of stateful networking functions (such as TCP) is becoming increasingly important. This transition not only enhances processing efficiency in modern networking environments where data transmission rates are rising, but it also reduces the inherent CPU overhead found in software implementations, allowing hardware devices to handle network traffic more efficiently. However, validating the correctness of these hardware designs poses significant challenges due to the complex timing requirements and the vast input space associated with packet-level properties.

The verification of packet-level properties requires coverage …

Not All Samples Are Created Equal: Task-Aware Informative Sampling And Adaptive Inference For Efficient Edge Ai, Rebati Gaire

School of Computing: Dissertations, Theses, and Student Research

The rapid proliferation of Internet of Things (IoT) devices has resulted in an unprecedented influx of data generated at the edge by billions of sensors. Traditional approaches relying on cloud-based processing are increasingly inadequate due to constraints in bandwidth, latency, and privacy. Edge computing has emerged as a transformative paradigm, enabling real-time data processing and decision-making by decentralizing computation to the edge. While the integration of deep learning into edge environments—termed edge intelligence—promises autonomous and personalized operations, it is hindered by challenges such as limited computational resources, energy constraints, and data redundancies.

This thesis addresses these challenges by presenting three …

Prevalence Of Autism Spectrum Characteristics In Students Taking Undergraduate Computing Courses, Rachel Michaela Mettenbrink

School of Computing: Dissertations, Theses, and Student Research

The incidence rate of autism spectrum condition (ASC) has increased significantly in recent decades, as awareness of the condition and its impacts increases amongst clinicians, parents, and the general population. Medical literature has proposed that there may be a relationship between ASC and participation in the computing field. This study tests for the prevalence of autism spectrum condition traits measured by delivering the Autism Spectrum Quotient (AQ) to a population of undergraduate computer science students. We examine the relationships between AQ scores and students taking undergraduate computer science classes, sex, socioeconomic status, and parents in the computing industry. Additionally, we …

Assessing Reproducibility Challenges In Clinical Metabolics, Darcy Lin Cochran

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

Current metabolomics research is expanding to be multiplatform and interdisciplinary. Metabolomic analysis has the potential to provide detailed insight into any biological system of interest to analyze the underlying molecular mechanisms of variables like environment, disease, and genetics. Human clinical metabolomics is a major research area that is often focused on finding biomarkers or panels of biomarkers for different diseases. However, results are difficult to compare across different laboratories since the field of metabolomics has yet to widely adopt best practices for sample preparation, data acquisition and data processing, results are difficult to compare across different laboratories.

This thesis focuses …

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 …

Deep Learning Vision-Based Bridge Inspection With Resource-Constrained Unmanned Aircraft Systems, Ji Young Lee

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

Bridge inspection is critical for ensuring structural integrity, extending the service life of infrastructure, and minimizing maintenance costs. As bridges age and endure increasing loads, regular inspections help detect early signs of wear, such as cracks or corrosion, that could impact safety and performance. However, traditional inspection methods are labor-intensive, requiring significant time, specialized equipment, and manual access to challenging areas, which can lead to costly disruptions. Additionally, reliance on human inspectors introduces subjectivity, with assessments varying by individual expertise. These factors highlight the inefficiencies and safety risks in current inspection practices, underscoring the need for more objective, efficient solutions. …

The Use Of Two-Dimensional Detectors For Snapshot And High Accuracy Imaging Ellipsometry, Jeremy A. Vanderslice

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

Ellipsometry is a powerful and sensitive optical technique used to characterize thin film thickness and optical properties by measuring changes in the polarization state of light upon reflection or transmission. This dissertation investigates novel ellipsometry configurations that use two-dimensional detectors to enhance measurement speed, spatial resolution, or accuracy of ellipsometry measurements. The study involves the development of three different ellipsometry configurations, encompassing mechanical prototypes, mathematical models, and test measurements to evaluate each system.

Advisor: Jeffrey Shield

Channel Estimation In Millimeter Wave Mimo Systems: The Tensor-Based Methods, Fei He

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

This dissertation presents two novel tensor-based methods for solving channel estimation (CE) problems in Millimeter Wave (mmWave) multiple-input multiple-output (MIMO) wireless communication systems. First, we proposed a method of tensor rank regularization with bias compensation for CE in a hybrid mmWave MIMO system. We modified the CANDECOMP/PARAFAC(CP) decomposition-based method and jointly estimated the tensor rank and channel factor matrices. It differs from most existing works by assuming that the number of channel paths is unknown, yet it can accurately estimate channel parameters without prior knowledge of the number of multipath components. The tensor rank is estimated by a novel sparsity-promoting …

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 …

Virtual Control: A Comparison Of Methods For Hand-Tracking Implementation, Nathan Roberts

Honors Program: Senior Projects (Public)

This thesis examines the design philosophy of modern virtual reality applications that utilize hand-tracking as a primary form of user input. The analysis presented hopes to provide ideas for future implementations of this technology so that more immersive experiences are developed. This analysis starts with the discussion of a modern example of successful hand-tracking implementation, then comparing that implementation to a recent senior design project. This comparison is primarily based on each experience’s ability to create interactivity and immediacy. Interactivity is the degree to which the user can quickly and reliably make changes to their virtual environment, while immediacy is …

Development And Characterization Of Organic Electrocatalysts For Use In Zinc-Air Batteries, Christopher John Merkel

Department of Chemical and Biomolecular Engineering: Dissertations, Theses, and Student Research

The global deployment of solar photovoltaic and wind power is projected by the International Energy Agency as the primary pathway to reduce dependence on fossil fuels. However, these technologies face a critical bottleneck: their inherently intermittent power generation. For “intermittent renewables” to become the dominant source of electrical energy, efficient energy storage systems are essential. Current storage solutions are not viable on a global scale due to material scarcity, safety concerns, and high capital costs. Among emerging technologies, zinc-air batteries (ZABs) have garnered significant interest. ZABs offer a theoretical energy density five times greater than traditional lithium-ion batteries, utilize safe …

Impacts Of Stream Bed Adjustment On Local Bridge Morphology At Highway 281, Molly G. Likins

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Nebraska sand-bed rivers have long been a part of sediment transport studies and have been used in the development of numerous well-known empirical bedload equations. Some of these studies have shown how adjustments in streambed elevation led to changes in local stream morphology. The sand-bed rivers of Nebraska are highly susceptible to such changes due to their wide, shallow cross-sections and erodibility. The objective of our study is to synthesize a hydrodynamic model with high-resolution field data and improved methods of representing sediment transport to better predict both short and long-term channel adjustments for an aggraded sand-bed river.

The field …

Numerical Study On The Behavior Of Natural And Recycled Aggregate Concretes, Shahriar Mardpour

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

This thesis investigates the mechanical behavior of natural and recycled aggregate concretes (NAC and RAC) using a multi-phase numerical approach to predict performance. Growing interest in sustainable materials has led to using recycled concrete aggregates (RCA) to replace natural aggregates, creating Recycled Aggregate Concrete (RAC). Due to their different structural components, RAC and NAC exhibit varying mechanical properties, particularly in strength and durability.

This study validated tension and bending (flexural) test models by comparing numerical results with similar models from the literature. Following validation, a multi-phase approach modeled NAC and RAC for the bending (flexural) and tension tests, providing a …

Development And Evaluation Of Highly Thixotropic Uhpc Mixtures For Bridge Overlay Applications, Akbota Aitbayeva

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Ultra-high-performance concrete (UHPC) is an advanced construction material renowned for its exceptional strength and durability. However, conventional UHPC is typically self-consolidating, making it unsuitable for bridge deck overlay applications due to challenges posed by potential surface slopes. UHPC overlay construction requires a highly thixotropic material that not only responds well to vibration but also maintains workability over an extended period and remains stable on sloped surfaces. Despite the complex rheological properties of highly thixotropic UHPC, limited testing methods are available to effectively assess the workability and rheology of overlay mixtures. To address this gap, the present study provides a comprehensive …

Exploring Variably Saturated Flow Formulations For Modflow: Implementing A Fully 3d Richards' Equation In Modflow 6, Sebastian Vazquez-Gasty

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

This thesis explores the implementation of a fully 3D Richards’ equation solution into MODFLOW 6 to solve for saturated/unsaturated flow. Currently, MODFLOW 6 has limited capability for solving unsaturated zone flow problems by using the Unsaturated Zone Flow (UZF) package, which neglects capillarity and assumes vertical 1-dimensional flow. Various formulations of the Richards’ equation were first evaluated for their strengths and weaknesses. Various numerical solution approaches to Richards’ equation were also studied to understand the robustness and efficiency of different approaches and to select one that would best fit into the MODFLOW 6 framework. The MODFLOW 6 framework was also …

Improving Thermionic Power Generation Via The Reduction Of Emission Barriers, Chace E. Franey

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

This thesis investigates methods to improve the performance of thermionic energy converters (TECs) by reducing the emission barriers. A TEC generates electricity from thermal energy when electrons are emitted from a hot electrode (the emitter) through a vacuum gap and absorbed by a cooler electrode (the collector). Due to their lack of working fluids and inherently compact nature, TECs have garnered attention over the years for their potential as a means of power generation in space or high-grade waste heat recovery. Historically, however, the practical implementation of TECs has been hindered by significant technical challenges. Recent advancements in microfabrication techniques …

Electrochemical Treatment Of Mining And Oilfield Wastewater Using Recycled Titanium Alloy Electrodes, Sean Michael Thompsen

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

This thesis explores the integration of circular economy principles into wastewater treatment through the innovative use of recycled Ti-6Al-4V titanium alloy electrodes. By repurposing titanium alloys from metal additive manufacturing (AM) waste, the research aims to address the treatment of acidic and oil-contaminated industrial wastewater in a sustainable manner. The recycled electrodes demonstrate notable stability and fouling resistance in challenging acidic conditions, attributed to their unique surface porosity and conductive properties. Electrochemical processes, including hydrogen evolution at the cathode, facilitate metal ion precipitation and destabilize surfactant-stabilized oil droplets. Cyclic voltammetry and long-term stability tests highlight the electrodes’ resilience, providing an …

Development Of A Surface-Mounted Strong Post For The Midwest Guardrail System, Gnyarienn Selva Kumar

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

This research investigated the development of a surface-mounted strong post for the Midwest Guardrail System (MGS), designed to replicate the behavior of the standard MGS post, a W6 x8.5, 72-in. long post embedded 40 in. into strong soil. The MGS is a strong post, W-beam guardrail system that has been successfully evaluated in many applications using crashworthiness criteria described in the American Association of State Highway and Transportation Officials (AASHTO) Manual for Assessing Safety Hardware (MASH). However, in some locations, conventional soil-embedded posts are impossible to install due to subgrade obstructions like concrete slabs, mow strips, utilities, and limited right-of-way. …

Argument Schema Of Undergraduate Engineering Students, Anu Singh

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

Critical thinking is one of the most desired skills in the workplace, as it assists an individual in solving complex problems and making informed decisions, resulting in their workplace success. Argumentation is one instructional approach that provides students an opportunity to engage in higher-order thinking and improve their communication skills. Argumentative writing provides opportunities to engage in multiple perspectives of a problem, provide evidence for the claim, evaluate evidence, engage in reasoning, and acknowledge self-bias, which automatically engages students in critical thinking. Previous literature has shown that despite the use of interventions and scaffolding approaches, students' argumentative texts lack elements …

Dynamics Of Flexible Freestanding Structures Under Ground Motion Excitation, Seyed Mohammadreza Farooghi Mehr

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

Freestanding structures are characterized by being unattached at the base, exhibiting rigid or flexible motion under ground motion excitation with various potential responses including rocking (rotation at the base about corner points), pure sliding, slide-rocking, and overturning. While rigid freestanding structures have been extensively studied, the behavior of flexible freestanding structures—particularly the interaction between modes involving sliding—remains underexplored. Existing literature has focused on the deformation and rocking motions of flexible freestanding structures through both analytical and experimental approaches, which have shown indications of sliding at the base. These findings highlight the necessity of incorporating sliding motion into analytical models to …

Association Between In Situ Ventilation And Human-Generated Aerosol Exposure In Meatpacking Plants During The Covid-19 Pandemic, Joshua L. Santarpia, Josephine Lau, Debayan Shom, Shanna A. Ratnesar-Shumate, Eric C. Carnes, Gearge W. Santarpia, Vicki L. Herrera, Danielle N. Rivera, Daniel N. Ackerman, Ashley R. Ravnholdt, John J. Lowe, Athena K. Ramos

Durham School of Architectural Engineering and Construction: Faculty Publications

During the COVID-19 pandemic, meatpacking workers were disproportionately affected by disease. Large outbreaks at meatpacking facilities resulted in loss of life and threatened the well-being of workers across the globe. Much work was done throughout the pandemic to understand and prevent these outbreaks. This study combined ventilation system evaluation and measurement of human-generated respiratory aerosol to investigate and identify areas of highest risk for disease transmission. These findings confirm that improved ventilation reduces exposure to human-generated aerosols in meatpacking facilities, including those that may contain infectious agents, such as SARS-CoV-2. This study suggests areas of greatest risk are likely areas …

Internet Of Things-Based Automated Solutions Utilizing Machine Learning For Smart And Real-Time Irrigation Management: A Review, Bryan Nsoh, Abia Katimbo, Hongzhi Guo, Derek M. Heeren, Hope Njuki Nakabuye, Xin Qiao, Yufeng Ge, Daran R. Rudnick, Joshua Wanyama, Erion Bwambale, Shafik Kiraga

Department of Agricultural and Biological Systems Engineering: Faculty Publications

This systematic review critically evaluates the current state and future potential of real-time, end-to-end smart, and automated irrigation management systems, focusing on integrating the Internet of Things (IoTs) and machine learning technologies for enhanced agricultural water use efficiency and crop productivity. In this review, the automation of each component is examined in the irrigation management pipeline from data collection to application while analyzing its effectiveness, efficiency, and integration with various precision agriculture technologies. It also investigates the role of the interoperability, standardization, and cybersecurity of IoT-based automated solutions for irrigation applications. Furthermore, in this review, the existing gaps are identified …

If Androids Dream, Are They More Than Sheep?: Westworld, Robots And Legal Rights, Amanda J. Dipaolo

Dialogue: The Interdisciplinary Journal of Popular Culture and Pedagogy

The robot protagonists in HBO’s Westworld open the door to several philosophical and ethical questions, perhaps the most complex being: should androids be granted similar legal protections as people? Westworld offers its own exploration of what it means to be a person and places emphasis on one’s ability to feel and understand pain. With scientists and corporations actively working toward a future that includes robots that can display emotion in a way that can convincingly pass as that of a person’s, what happens when androids pass the Turing test, feel empathy, gain consciousness, are sentient, or develop free will? The …

Accelerated Bridge Construction (Abc) Decision Tool, Phil Barutha, Marc Maguire, Elio Saldana, Fray F. Pozo-Lora

Nebraska Department of Transportation: Research Reports

This report investigates the creation and assessment of a decision-making tool developed to aid the Nebraska Department of Transportation (NDOT) in determining the suitability of the Accelerated Bridge Construction (ABC) method for bridge replacement projects. The tool utilizes the Analytic Hierarchy Process (AHP) to integrate different criteria, including Average Daily Traffic (ADT), Average Daily Truck Traffic (ADTT), detour time, railroad impact, economy of scale, and the use of typical details, which were found to be paramount in the decision-making process across the state. A sensitivity analysis was conducted to evaluate the tool’s performance and identify the most significant factors influencing …

Effect Of Antioxidant Additives And Recycling Agents On Performance Of Asphalt Binders And Mixtures – Phase Ii, Nitish R. Bastola, Muhammad Ahmad, Mahdieh Khedmati, Jamilla Teixeira, Hamzeh Haghshenas

Nebraska Department of Transportation: Research Reports

The use of reclaimed asphalt pavement (RAP) in combination with recycling agents (RAs) (i.e., rejuvenators or softening agents) has gained significant attention from the pavement industry as a sustainable pavement solution, reducing the carbon footprint of manufactured products through the conservation of energy and reduction on the use of raw materials. Current research has found that RAs can improve RAP recycled asphalt mixture’s cracking resistance, while being capable of maintaining their rutting resistance. However, there are some concerns about the effect of RAs on the moisture damage resistance and the long-term performance (aging) of these additives. The current need is …

Development Of Crop2cloud: An Iot-Integrated Platform For Automated Irrigation Scheduling Using Multi-Source Stress Indices, Bryan Nsoh

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

Efficient water management in agriculture is critical, as irrigation accounts for 70% of global freshwater withdrawals. While precision agriculture technologies offer potential solutions, integrating diverse data streams for real-time irrigation scheduling remains challenging, particularly in combining plant and soil-based stress indicators. This research addresses these challenges through three interconnected studies.

A systematic review first examined the current state and future potential of IoT-based automated irrigation management systems, analyzing how these technologies can enhance agricultural water use efficiency and crop productivity. The review identified critical gaps in data integration and real-time processing while highlighting opportunities for combining multiple stress indices for …

Implementation Of Mash Surrogate Test Vehicles For Sign Supports, Breakaway Poles, And Work Zone Traffic Control Devices, Mahfuza Rahman Doreen

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

This describes the development of two surrogate test vehicles, or "bogie vehicles," for performing compliance testing of breakaway devices found on the roadside according to the American Association of State Highway and Transportation Officials (AASHTO) Manual for Assessing Safety Hardware (MASH). Historically, surrogate vehicle testing and approval of roadside structures was not permitted, because critical vehicle behaviors could not be emulated using the existing or modified rigid frame structures. Therefore, Project NCHRP 22-55 was funded to develop two reusable bogie vehicles to emulate the MASH 1100C small car and 2270P pickup truck. This thesis describes the background data collection, initial …