Engineering Commons^™

Signal Modeling Of High Purity Germanium Detectors, Brooke Parker Thibodeau

Honors Scholar Theses

Pulse shape analysis can be used to analyze radiation incident on a semiconductor diode detector. Finite element analysis (FEA) can be used to simulate high purity germanium detectors with user-specified geometry, impurity concentration, and bias voltage. Subsequent streamline calculation can be used to conduct pulse shape analysis for single and multiple site gamma-ray interactions within the detector volume. Cross sections of the detector can be visualized by contour plots of the electric field, drift velocity magnitude, and collection time, as well as t30 and t90 rise-time values.

Cooperative And Bifunctional Ga-Ca-Cr2o3@Cao Structured Monoliths As Versatile Platform For Reactive Capture Of Co2 And Its Subsequent Conversion To Ethylene, Khaled Baamran, Ali A. Rownaghi

Chemical and Biochemical Engineering Faculty Research & Creative Works

Cooperative and bifunctional materials (BFMs) that integrate adsorbents and catalysts offer a promising strategy for the reactive capture of CO₂ to produce valuable fuels and chemicals. In this study, we developed structured BFMs via 3D printing that combine CaO as an adsorbent with Ga–Ca–Cr₂O₃ metal oxides as the catalyst for the reactive capture of CO₂ and its subsequent conversion to C₂H₄ via the oxidative dehydrogenation of C₂H₆ (CO₂-ODHE). Three different Ga–Ca compositions were used to modify the catalyst surface characteristics and enhance C₂H₄ selectivity. …

Assessing Sleep Quality In A Preclinical Model Of Low Back Pain Through Novel Noninvasive Methods, Lydia C. Saltz

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

Chronic low back pain (LBP) has widespread negative impacts on quality of life. Current treatments for chronic LBP fail to provide long-term efficacy and motivate the need to understand key drivers of poor patient outcomes. Mounting evidence indicates that sleep disturbances and chronic LBP have a strong reciprocal relationship. Women may be particularly vulnerable to the negative impacts of the sleep-pain axis, exhibiting greater prevalence in both conditions. However, the relationship between sleep, pain, and sex remains understudied. Preclinical models can be used to parse out characteristic sleep features that degrade with pain, which can be further broken out by …

A Comprehensive Analysis Of Virtual Reality In Modern Healthcare Education, Adarsha Ganesan

Honors Program: Senior Projects (Public)

This thesis evaluates the effectiveness of virtual reality (VR) in healthcare education through multiple facets of evaluation: educational outcomes, accessibility considerations, and financial viability. Drawing from an extensive literature review on existing research and a case study of the University of Nebraska Medical Center (UNMC) College of Nursing's "Journey Through the Kidney" VR experience, this analysis examines how technology can transform modern medical education. While research shows mixed results regarding virtual reality’s impact on assessment outcomes, studies demonstrate increased student motivation and engagement, which can have lasting downstream effects on the quality of learning. Accessibility analysis reveals both opportunities and …

Drainage Area Limitations Of Single Watershed, Peak Flow Estimates From Nrcs Methods, Timothy A. Maughan, Rollin H. Hotchkiss, Riley Hales

Nebraska Department of Transportation: Research Reports

Most state Department of Transportation roadway design sections predict peak flow for culvert design using, amongst other approaches, Natural Resources Conservation Service (NRCS) TR-20 technology. Even though this technology is more than 50 years old, there are no clear guidelines for how large a single watershed drainage area may be while remaining appropriate for predicting peak discharge with this method. Our objective was to identify the drainage area where TR-20 peak flow predictions significantly deviate from flow frequency predictions. We developed flow frequency estimates for 130 small-area stream gage sites in rural Nebraska and compared the calculated return period discharges …

Conversion Of Thermal Energy Stored In Conductive Concrete To Electricity With Thermoelectric Generators, Moustafa M. Al Adawi

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

This paper presents a proof-of-concept experimental study on the use of conductive concrete as thermal energy storage and its conversion into electricity. The conductive concrete is heated to 100°C by supplying electricity, and the stored thermal energy is converted back into electricity using thermoelectric generators (TEGs). Measurement results demonstrate that the conductive concrete effectively stores thermal energy up to 100°C, and this energy can be successfully converted into electricity. The findings highlight the potential of conductive concrete as a reliable medium for thermal energy storage.

Advisor: Lim Nguyen

A Machine Learning Framework For Packet Anomaly Detection In Smartgrid Substation Networks, Sowmya Bandari

School of Computing: Dissertations, Theses, and Student Research

The increasing reliance on Smart Grid Substation Networks for efficient electricity distribution has amplified cybersecurity vulnerabilities, particularly within Supervisory Control and Data Acquisition (SCADA) systems. The IEC 60870-5-104 (IEC-104) protocol, widely adopted for communication between Remote Terminal Units (RTUs) and Human-Machine Interfaces (HMIs), lacks inherent encryption and authentication mechanisms, rendering it susceptible to sophisticated cyberattacks. Threats such as False Data Injection Attacks (FDIAs), command injection, covert attacks and replay attacks pose significant risks by manipulating grid control signals, potentially leading to undetected operational disruptions, cascading failures, or system-wide instability. Conventional signature-based Intrusion Detection Systems (IDS) often fail to identify zero-day …

An Integrative Approach To Einstein’S Field Equations Of General Relativity For High School Students, Christina M. Aintablian

Senior Honors Theses

Einstein’s Field Equations form the foundation of the theory of General Relativity, describing the interdependence of mass-energy and spacetime curvature, where curvature gives rise to gravity. However, the complexity of these equations makes them difficult for high school students to grasp. The mathematical framework of General Relativity is introduced step by step, beginning with relative motion and culminating in a discussion of complex phenomena that challenge modern physics. Each explanation intertwines core concepts of relativity with pre-established mental models to enhance learning. Through the use of figures, analogies, narratives, and thought experiments, a structured framework is developed to make relativity …

Impact Of Lost Synchronous Generation On The Rate Of Change Of Frequency In Electrical Power Systems, Damien Doheny

Doctoral

Renewable energy targets have resulted in high penetration of non-synchronous generation and consequently reducing power system inertia, and this could lead to power system frequency instability following a disturbance, such as the loss of generation. A concern to power system operators is the rate of change of frequency (ROCOF) following the loss of generation. Fast ROCOF presents many challenges for power systems but the primary concern is that fast ROCOF reduces the time-frame that primary frequency control has to arrest a frequency decline following the loss of generation. Therefore, power system operators need to develop strategies to operate power systems …

Finding Groundwater With Electricity: Research And Testing Of An Electro-Resistive Ground-Surveying Device For Use In Well-Drilling Applications, Samuel L. Heath

Senior Honors Theses

A custom-built electro-resistive water detection device is tested under various conditions to evaluate its overall performance and sensitivity to changing variables. The tests, designed to assess accuracy and precision, revealed that the prototype exhibits high reliability (~ 99%) for both Schlumberger and Wenner arrays across different electrode spacings and soil conditions. Moreover, the measured resistivity values from the soil tests aligned with established literature ranges for each soil type. The device also showed the ability to consistently detect changes in soil water content by producing measurable variations in resistivity. At a total cost of $181, this prototype can serve as …

Physics Embedded Neural Network: A Novel Data-Free Numerical Method For Solving Computational Physics Problems, Pawan Gaire

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

A novel approach for solving partial differential equations (PDEs) using neural networks for scientific computing is introduced. The proposed approach, referred to as physics-embedded neural network (PENN), features a unique architecture that incorporates the PDE and boundary conditions information directly within the final fully-connected layer of the feed-forward neural network (NN). The key aspect of PENN is the parallel numerical embedding of a differential equation associated with physical problems within the activation function of the network’s final layer. This integration leads to a new class of computational solvers competitive with classical methods like the Finite Element Method (FEM) and capable …

Carbon Fiber Cv Tripod Axle Design: Husker Motorsports Formula Sae, Taylor D. Boudreaux

Honors Program: Senior Projects (Public)

The 2024–2025 HMS Formula SAE senior design team successfully reduced axle system weight, cost, and improved manufacturability using a bonded tripod joint and ±45° intermediate modulus carbon fiber tube. The final design was validated on HMS 25, with no failures under rigorous testing.

Budget:
/="/"> Total project cost was $1,165.64, exceeding the initial $1,000 target due to unanticipated test rig expenses. However, per-axle production cost was reduced from $525.31 to $383.37 through in-house manufacturing, use of on-hand epoxy (DP460), and switching to cost-effective 7068 aluminum. The axle-specific cost was $766.74.

Timeline:
/="/"> Despite early delays from building a torsional testing …

A Case Study On Readiness Of Engineers In Agricultural Technology Start-Ups, Katie Marie Mowat

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

This dissertation explores the perceptions of practicing engineers regarding the skills necessary to be workforce-ready at agricultural technology (ag-tech) start-ups in the Midwestern United States. A qualitative case study methodology is leveraged, combining both interview and job description data. Given their uniqueness, the study divides the ag-tech start-up industry into two subcases: livestock and cropping systems. The Work Readiness Integrated Competence Model (WRICM) is used as the theoretical framework for this study and informs the conceptual framework and analysis processes. The study identified skills that fit into thirteen distinct categories, which are further grouped into four overarching resource groups. Skills …

Optimizing Nitrogen Management: Assessing Nitrate Transport In The Deep Vadose Zone And Its Impact On Groundwater Quality In East-Central Nebraska, Muili O. Lawal

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

Groundwater contamination by nitrate (NO₃-N) is a growing environmental and public health concern driven largely by intensive agricultural fertilizer applications. The vadose zone plays an important role in NO₃-N transport, influencing groundwater quality and agricultural sustainability. This study investigated NO₃-N leaching dynamics in the deep vadose zone of Water Quality Sub-Area 30 (WQA30) within the Lower Loup Natural Resources District (LLNRD), northeast of Columbus, Nebraska (mean groundwater NO₃-N: 20.3 mg/L), using soil cores from 16 shallow (to 6.1 m) and four deep (down to 25.9 m) across four zones, two with inorganic fertilizer (Zones 1 and 4) and two with …

Modeling Degradation In Li-Ion Batteries: Analyzing Single-Cell Degradation And Applying It To Customized Pack-Level, Mohannad Y. Alkhalil

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

The rapid expansion of lithium-ion (Li-ion) battery applications in areas such as electric vehicles (EVs), renewable energy storage, and portable electronics has drawn attention to the need for improving their performance, safety, and longevity. As Li-ion batteries become essential across technologies, understanding degradation mechanisms is critical for optimizing design and ensuring reliable operation. This work provides a detailed overview of modeling degradation in Li-ion batteries, focusing on single-cell behavior and its implications for pack-level performance.

The PyBaMM (Python Battery Mathematical Modeling) package, an open-source battery simulation tool written in Python, is used for single-cell simulations. Liionpack, another Python-based library, is …

Effects Of Processing And Microstructure On The Oxidation Of Zrb2-Sic In Co2, Marharyta Lakusta, Jeremy L. Watts, William G. Fahrenholtz, David W. Lipke

Materials Science and Engineering Faculty Research & Creative Works

Oxidation kinetics and oxide scale microstructures were compared for ZrB2-30 vol% SiC composites fabricated by hot press sintering of powders and by pressure less sintering of additively manufactured billets. Oxidation in CO₂ was conducted at temperatures up to 1400 °C with durations up to 900 h. All specimens exhibited parabolic oxidation kinetics. Materials with similar composition but different processing histories exhibited differences in oxidation behavior that become evident at extended durations (200–900 h) and higher temperatures (1200–1400 °C). Oxidation rates generally increased with grain size, e.g., at 1000 °C for 200 h, oxide scale thickness increased from 36 to …

Interfacial Defect Properties Of High-Entropy Carbides: Stacking Faults, Shockley Partial Dislocations, And A New Evans-Polanyi-Semenov Relation, Samuel E. Daigle, Stefano Curtarolo, William G. Fahrenholtz, Jon Paul Maria, Douglas E. Wolfe, Eva Zurek, Donald W. Brenner

Materials Science and Engineering Faculty Research & Creative Works

Using first principles calculations, {111} intrinsic stacking fault (ISF) energies in groups IVB, VB, and VIB high-entropy transition metal carbides (HETMCs) are shown to be predictable from an optimized rule of mixtures based on the atomic arrangement near the stacking fault. A composition-independent linear relationship is demonstrated between the ISF energies and the unstable stacking fault (USF) energies along the (112¯){111} γsurface slip path. This relationship represents a new application of the Evans-Polanyi-Semenov principle by treating the ISF and USF energies as analogous to the heat of reaction and transition state barrier in chemical reactions. Further, a full defect energy …

Picosecond Laser Ranging At 1.5 Μm Using Dispersive Interferometry, Behzad Boroomandisorkhabi, Xiangrui Su, Mina Esmaeelpour

Electrical and Computer Engineering Faculty Research & Creative Works

Precise displacement measurement is essential for engineering, industrial, and scientific purposes. Ultrafast laser techniques are preferred for real-time applications due to their single-shot measurement capability and high resolution. To create a high-performance and cost-effective system with less complexity, capable of achieving real-time measurement with high micrometer spatial resolution, we have used a picosecond pulsed laser at the telecommunication wavelength of 1.5 μm in combination with dispersive interferometry. The instantaneous frequency measurement took place using the time-stretch technique incorporating dispersion compensating fiber induced chirp. Results using a 7-picosecond laser at 1.5 μm with a 10 MHz repetition rate are presented. Frequency …

Mechanistic Investigation Of Ring-Opening Polymerization Of Polycaprolactone Using Tin(Ii) Catalysts: Ligand Effects And Biomedical Applications, Eva-Larue M. Barber

Honors Scholar Theses

This research explores the mechanistic aspects of ring-opening polymerization (ROP) of ε-caprolactone (CL) to produce polycaprolactone (PCL), a biodegradable polymer widely used in biomedical applications. The study investigates how light exposure and catalyst concentration influence polymerization efficiency, using tin(II) 2-ethylhexanoate [Sn(Oct)₂] as the catalyst in a non-polar toluene solvent at 90 °C. Reactions were conducted under either ambient light or black light bulb (BLB) illumination, with monomer-to-catalyst ratios of 1:1 and 200:1.

Proton nuclear magnetic resonance (¹H NMR) spectroscopy was used to analyze conversion efficiency by tracking the disappearance of monomer signals and appearance of characteristic PCL peaks. Results revealed …

Stability Analysis Of Turbulent Fluid Flow, Adam D. Schroeder

Mathematics, Statistics, and Computer Science Honors Projects

Hydrodynamic stability refers to the study of when and how laminar flows transition to turbulence. This includes investigations of the mechanisms of transition, as well as the classification of known flow configurations as either stable or unstable and the identification of critical values of flow parameters at which this bifurcation occurs. In this thesis, we introduce the mathematical theory behind continuum mechanics and fluid dynamics as well as some tools from the study of dynamical systems. We apply these concepts to the linear stability analysis of zero pressure gradient flat plate flow via numerical simulations in OpenFOAM, discussing both the …

Manipulating Martensitic Transformation And Residual Stress Development In Stress Superposed Incremental Forming Of Ss304, Elizabeth M. Mamros, Fabian Maaß, Thomas Gnaupel-Herold, A. Erman Tekkaya, Brad L. Kinsey, Jinjin Ha

Faculty Journal Articles

Stress superposition is one of the strategies used in metal deformation processes to increase the material formability, decrease the required forming forces, and create highly customized components. To investigate the effects of tensile and compressive stresses superposed to the single point incremental forming (SPIF) process, experiments and numerical simulations were conducted for a stainless steel 304 (SS304) truncated square pyramid geometry. Tensile stresses were superposed in-plane on the specimen blank by a custom hydraulic frame, and compressive stresses were incorporated via a polyurethane die. Identified parameters for a martensitic transformation kinetics model for SS304 were used in a two-step finite …

Observing Mesospheric Gravity Waves With Nasa's Awe Mission And Correlating To Gnss Tec Maps, Jaime Aguilar Guerrero, Björn Bergsson, Sehin Mesfin, Pavel Inchin, Matthew Zettergren, Ludger Scherliess, Yucheng Zhao, Dominique Pautet

Space Dynamics Laboratory Publications

The Atmosphere Waves Experiment (AWE) is a NASA mission launched on November 9, 2023, and installed on the International Space Station (ISS). Its primary goal is to detect and characterize atmospheric gravity waves (AGWs) by measuring Earth’s mesospheric hydroxyl (OH) airglow with its key instrument, the Advanced Mesospheric Temperature Mapper (AMTM). Since its deployment, AWE has been quantifying the seasonal and regional variability of AGWs, investigating their occurrence and potential sources, and enabling the assessment of their broader impact on the atmosphere by comparing measurements at different altitudes by other instruments. AWE has collected extensive imagery and temperature data capturing …

Hierarchical Frameworks For Scaling-Up Multi-Agent Coordination, Minghong Geng

Research Collection School Of Computing and Information Systems

Multi-agent reinforcement learning has emerged as a powerful framework for developing collaborative behaviors in autonomous systems. However, existing MARL methods often struggle with scalability in terms of both the number of agents and decision-making horizons. My research focuses on developing hierarchicalapproaches to scale up MARL systems through two complementary directions: structural scaling by increasing the number of coordinated agents and temporal scaling by extending planning horizons. My initial work introduced HiSOMA, a hierarchical framework integrating self-organizing neural networks with MARL forlong-horizon planning, and MOSMAC, a benchmark for evaluating MARL methods on multi-objective MARL scenarios. Building on these foundations, my recent …

Networked Multi-Agent Deep Reinforcement Learning Framework For The Provision Of Ancillary Services In Hybrid Power Plants, Muhammad Ikram, Daryoush Habibi, Asma Aziz

Research outputs 2022 to 2026

Inverter-based resources (IBRs) are becoming more prominent due to the increasing penetration of renewable energy sources that reduce power system inertia, compromising power system stability and grid support services. At present, optimal coordination among generation technologies remains a significant challenge for frequency control services. This paper presents a novel networked multi-agent deep reinforcement learning (N—MADRL) scheme for optimal dispatch and frequency control services. First, we develop a model-free environment consisting of a photovoltaic (PV) plant, a wind plant (WP), and an energy storage system (ESS) plant. The proposed framework uses a combination of multi-agent actor-critic (MAAC) and soft actor-critic (SAC) …

Development Of A Probabilistic Interaction Rule And Failure Pressure Model For Pipelines With A Colony Of Corrosion Defects, Kiswendsida J. Kere

Civil and Environmental Engineering Faculty Research and Publications

The interaction effect originating from a defect colony can pose a higher pipeline failure risk than the case when such possible interaction is not considered. Recognizing the limitations in existing models that can lead to inaccurate pipeline integrity assessment, the goal of this study is to develop a probabilistic interaction rule and predictive burst failure pressure model for pipelines with a colony of corrosion defects. First, a comprehensive database of burst failure pressure for pipes with a colony of corrosion is established that encompasses a wide range of influencing factors (e.g., spacing, defect sizes, and material properties) on the defect …

A Novel Macroscale Model For Deformation Twinning In Magnesium Alloys, Daniel S. Kenney

Doctoral Dissertations and Projects

The characterization of deformation twinning in magnesium alloys is evaluated with macroscale modeling to predict material behavior and microstructure evolution with Internal State Variables (ISVs). Twinning in magnesium presents key challenges with constitutive modeling at the macroscale where the large number of grains with individual slip/twin must be generalized. This research proposes the Kearns factor (Kearns, 1965) as a method for quantifying the crystallographic texture associated with twinning and shows how the change in Kearns factors is associated with tension-compression asymmetry, anisotropic yielding and hardening, and anisotropic lateral strains. The material model developed in this work proposes a second rank …

Modelling Virus Filtration And Virus Reduction By An Advanced Multilayer Model: Retention Distribution And The Effect Of Product Aggregates, Hironobu Shirataki, Remo Leisi, Junji Hdaka, S. Rancil Wickramasinghe

Chemical Engineering Faculty Publications and Presentations

Robust virus reduction and high permeability are characteristic properties of virus filters, which are modeled as having an asymmetric multilayer membrane structure with a pore size distribution. In this study, an advanced heterogeneous multilayer model for the multicomponent solution containing viruses, protein monomers and aggregates, has been developed to reproduce the filtration behavior, virus reduction, and virus/protein retention distribution in the virus filter with asymmetric membrane structure. Calculations based on the multilayer membrane structure with consideration of the effect of aggregate size and concentration numerically reproduce the experimental results that virus LRV (log reduction value) decreases when a large number …

Evaluation Of Novel Jointless Engineered Cementitious Composite Ultrathin Whitetopping (Ecc-Utw) Overlay, Hassan Noorvand, Marwa Hassan, Tyson Rupnow, Ricardo Hungria

Publications

The present work corresponds to the development and the application of a cost-effective Engineered Cementitious Composites (ECC) mix design with the name M3-1.5%. Once the material was developed it was applied in the construction of a novel engineered cementitious composites ultrathin whitetopping (ECC-UTW) overlay. The overlay was constructed in May 2019 at the Pavement Research Facility (PRF) in Port Allen, Louisiana. The project was built on top of a distressed asphalt pavement corresponding to a previous project. During the construction, samples were gathered and subjected to testing after 28 days through means of compressive, uniaxial tension and flexural strength tests. …

Understanding The Breadth And Impact Of The Ias [President’S Message], Ayman El-Refaie

Electrical and Computer Engineering Faculty Research and Publications

No abstract provided.

Propasafe: A Bert-Based Offline Tool For Propaganda Detection, Vivek Sharma, Mohammad Mahdi Shokri, Shweta Jain, Sarah Ita Levitan, Elena Filatova

Publications and Research

In an era marked by the rapid consumption of digital news, the proliferation of propaganda poses significant threats to democratic values and informed decision-making. We propose a novel framework that prioritizes user privacy while assisting in the automatic detection of propaganda in news articles, allowing users to sift through the rhetoric to read the relevant objective news. As a demonstration of this framework, we present Propasafe, a BERT-based browser extension designed to alert users to propagandist tones in news articles. By highlighting instances of propaganda-like language in real-time, Propasafe empowers users to critically engage with news content, promoting objective understanding …