Engineering Commons^™

Exploring Regular And Turbulent Flow States In Active Nematic Channel Flow Via Exact Coherent Structures And Their Invariant Manifolds, Caleb G. Wagner, Rumayel H. Pallock, Jae Sung Park, Michael M. Norton, Piyush Grover

Department of Mechanical and Materials Engineering: Faculty Publications

This work is a unified study of stable and unstable steady states of 2D active nematic channel flow using the framework of Exact Coherent Structures (ECSs). ECSs are stationary, periodic, quasiperiodic, or traveling wave solutions of the governing equations that, together with their invariant manifolds, organize the dynamics of nonlinear continuum systems. We extend our earlier work on ECSs in the preturbulent regime by performing a comprehensive study of stable and unstable ECSs for a wide range of activity values spanning the preturbulent and turbulent regimes. In the weakly turbulent regime, we compute more than 200 unstable ECSs that coexist …

Co2 Storage Capacity And Injectivity Of Stacked Carbonates Of The Pennsylvanian And Permian In Western Nebraska, Lateef Lawal

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

Geological carbon storage (GCS) is a critical aspect of carbon capture and storage (CCS) in which captured CO₂ from power plants and industrial processes is injected and stored securely underground. Potential subsurface rock formations include saline aquifers, depleted oil and gas reservoirs, unmineable coal seams and volcanic rocks. GCS technology has been proven in the United States and many other parts of the world as a net-zero carbon emission strategy to mitigate the current climate crisis of our planet. Unlike other states such as Wyoming, GCS projects are still in the early phases in Nebraska. The goal of this …

Amorphous Boron Carbide-Amorphous Silicon Heterojunction Devices, Vojislav Medic

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

This dissertation will show successful development and characterization of amorphous boron carbide-amorphous silicon heterojunction device with potential for neutron detection. The amorphous hydrogenated boron carbide (a-BC:H) has been extensively researched as a semiconductor for neutron voltaic device fabrication. Naturally occurring boron contains 19.8% of boron isotope B¹⁰ that has a high absorption cross section of thermal neutrons at lower energies, and boron carbide contains 14.7% of that B¹⁰ isotope. Therefore, as a semiconductor compound of boron a-BC:H has the ability to absorb radiation, generate charge carriers, and collect those carriers. Previous work on a-BC:H devices investigated the fabrication …

Enhanced Privacy-Enabled Face Recognition Using Κ-Identity Optimization, Ryan Karl

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

Facial recognition is becoming more and more prevalent in the daily lives of the common person. Law enforcement utilizes facial recognition to find and track suspects. The newest smartphones have the ability to unlock using the user's face. Some door locks utilize facial recognition to allow correct users to enter restricted spaces. The list of applications that use facial recognition will only increase as hardware becomes more cost-effective and more computationally powerful. As this technology becomes more prevalent in our lives, it is important to understand and protect the data provided to these companies. Any data transmitted should be encrypted …

An Investigation Of Match For Lossless Video Compression, Brittany Sullivan-Reicks

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

A new lossless video compression technique, Match, is investigated. Match uses the similarity between the frames of a video or the slices of medical images to find a prediction for the current pixel. A portion of the previous frame is searched to find a matching context, which is the pixels surrounding the current pixel, within some distance centered on the current location. The best distance to use for each dataset is found experimentally. The matching context refers to the neighborhood of w, nw, n, and ne, where the pixel in the previous frame with the closest matching context becomes the …

Low-Power, Event-Driven System On A Chip For Charge Pulse Processing Applications, Joseph A. Schmitz

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

This dissertation presents an electronic architecture and methodology capable of processing charge pulses generated by a range of sensors, including radiation detectors and tactile synthetic skin. These sensors output a charge signal proportional to the input stimulus, which is processed electronically in both the analog and digital domains. The presented work implements this functionality using an event-driven methodology, which greatly reduces power consumption compared to standard implementations. This enables new application areas that require a long operating time or compact physical dimensions, which would not otherwise be possible. The architecture is designed, fabricated, and tested in the aforementioned applications to …

Sc-Fuse: A Feature Fusion Approach For Unpaved Road Detection From Remotely Sensed Images, Aniruddh Saxena

School of Computing: Dissertations, Theses, and Student Research

Road network extraction from remote sensing imagery is crucial for numerous applications, ranging from autonomous navigation to urban and rural planning. A particularly challenging aspect is the detection of unpaved roads, often underrepresented in research and data. These roads display variability in texture, width, shape, and surroundings, making their detection quite complex. This thesis addresses these challenges by creating a specialized dataset and introducing the SC-Fuse model.

Our custom dataset comprises high resolution remote sensing imagery which primarily targets unpaved roads of the American Midwest. To capture the diverse seasonal variation and their impact, the dataset includes images from different …

Husker Motorsports Active Drag Reduction System, Creighton Hughes, Evan Killian, Micah Busboom, Aj Johnson, Jude Steffen

Honors Program: Senior Projects (Public)

Formula SAE is a multifaceted competition that involves student teams designing and competing with an open-wheel style race car. There are 5 different dynamic events included in the competition. Each event requires a unique aerodynamic setup to have the best performance possible. This design project focuses on a drag reduction system (DRS) that will improve aerodynamic performance, resulting in faster lap times and increased competitiveness. Key features include a direct electronic actuation mechanism that will allow the rear wing to be adjusted during a race. The benefits of the DRS system, include increased speed, improved handling, and greater fuel efficiency …

Enhancing Urban Water Quality Through Biological-Chemical Treatment: Aquatic Macroinvertebrate Community And Temporal Chlorophyll-A Response, Matthew Chaffee

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

With a growing human population, urbanization is impeding a plethora of natural waterways. Of these, urban ponds play a vital role in nutrient sequestration, flood prevention, and habitat sanctuaries. However, nutrient loading can reduce habitat effectiveness and promote harmful algae blooms. To reduce internal nutrient loads, a biological-chemical treatment strategy consisting of floating treatment wetlands (FTWs) and lanthanum were applied to two urban retention ponds, Densmore and Wilderness Ridge Ponds. To measure effectiveness, chlorophyll-a samples were collected and correlated with Sentinel-2. A novel band algorithm termed 3BR1 produced a strong correlation (R² = 0.72) to physical chlorophyll-a …

Responses Of Maize To Different Irrigation Regimes In Semi-Arid Western Nebraska, Swathi Palle

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

As the “Cornhusker State”, Maize (Zea mays) is an important crop in Nebraska. However, farmers in the state are challenged by unstable supply of surface water and limited groundwater resources. A better understanding of maize's response to water stress that occurs at different growth stages can help implement the best irrigation practices that conserve water while maintaining yields. In this study, we conducted field experiments at the Panhandle Research, Extension, and Education Center to compare the responses of maize to eight irrigation treatments which included both limited and deficit irrigation regimes during 2022 and 2023 growing seasons. Specifically, …

Renovating The Ipmu Via Internet Of Things For Pollutant Emission Estimations In Poultry Facilities, Joshua Dotto

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

The emissions of ammonia (NH₃), particulate matter (PM_2.5), and carbon dioxide (CO₂) are major concerns in poultry facilities. They can pose environmental concerns and nuances. Robust and affordable measurement systems are needed to accurately measure in-barn concentrations and quantify the emissions.

The Intelligent Portable Monitoring Unit (iPMU or PMU3) developed in 2016 was reconstructed into PMU4 to include upgraded NH₃ and PM_2.5 sensors and wireless connectivity for a low-cost, robust, and accurate air quality monitoring device with contactless data transfer using the concept of Internet of Things (IoT). In addition, a user-friendly …

Structural Performance And Resiliency Of Reinforced Concrete Bridge Pier Columns, Multi-Column Piers, And Bridge Systems Subjected To Multiple Hazards – Fire, Collision, And Air Blast, Qusai Abdulkarim Alomari

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

Given their close proximity to traffic and improper employment of protective systems, bridges and bridge piers are vulnerable to multi-hazard events triggered by vehicle collisions coupled with correlated and cascading events, such as explosions and fires. Despite recent catastrophic incidents that have highlighted the profound consequences of these extreme demands, including substantial damage, adverse economic impact, and loss of life, there has been a notable lack of research investigating the performance of bridges and bridge structural components under the aforementioned multi-hazards. Furthermore, current bridge design codes do not address these events assuming that, after these destructive events, replacement of the …

On Dyadic Parity Check Codes And Their Generalizations, Meraiah Martinez

Department of Mathematics: Dissertations, Theses, and Student Research

In order to communicate information over a noisy channel, error-correcting codes can be used to ensure that small errors don’t prevent the transmission of a message. One family of codes that has been found to have good properties is low-density parity check (LDPC) codes. These are represented by sparse bipartite graphs and have low complexity graph-based decoding algorithms. Various graphical properties, such as the girth and stopping sets, influence when these algorithms might fail. Additionally, codes based on algebraically structured parity check matrices are desirable in applications due to their compact representations, practical implementation advantages, and tractable decoder performance analysis. …

Development Of A Machine Learning System For Irrigation Decision Support With Disparate Data Streams, Eric Wilkening

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

In recent years, advancements in irrigation technologies have led to increased efficiency in irrigation applications, encompassing the adoption of practices that utilize data-driven irrigation scheduling and leveraging variable rate irrigation (VRI). These technological improvements have the potential to reduce water withdrawals and diversions from both groundwater and surface water sources. However, it is vital to recognize that improved application efficiency does not necessarily equate to increased water availability for future or downstream use. This is particularly crucial in the context of consumptive water use, which refers to water consumed and not returned to the local or sub-regional watershed, representing a …

In Situ Water Sensing Systems: Research On Advancements In Environmental Monitoring, Abigail Seibel

Honors Program: Senior Projects (Public)

In this work, two sensing systems were researched in order to improve in situ environmental monitoring. The first is a pH and Total Alkalinity sensor used to determine these characteristics of sea water. I explored the facets of this sensor over a 7-week internship with Dr. Ellen Briggs in her lab in summer of 2023. The second is a more holistic sensing system that reads temperature, turbidity, and pressure used for studying environmental characteristics of Alaskan bever ponds. Both systems were developed in close collaboration with scientists who are collecting data to better understand the impacts of climate change. Better …

Surface Antibody Changes Protein Corona Both In Human And Mouse Serum But Not Final Opsonization And Elimination Of Targeted Polymeric Nanoparticles, Sara Capolla, Federico Colombo, Luca De Maso, Prisca Mauro, Paolo Bertoncin, Thilo Kähne, Alexander Engler, Luis Núñez, Gustavo Larsen, Et Al.

Department of Chemical and Biomolecular Engineering: Faculty Publications

Background: Nanoparticles represent one of the most important innovations in the medical field. Among nanocarriers, polymeric nanoparticles (PNPs) attracted much attention due to their biodegradability, biocompatibility, and capacity to increase efficacy and safety of encapsulated drugs. Another important improvement in the use of nanoparticles as delivery systems is the conjugation of a targeting agent that enables the nanoparticles to accumulate in a specific tissue. Despite these advantages, the clinical translation of therapeutic approaches based on nanoparticles is prevented by their interactions with blood proteins. In fact, the so-formed protein corona (PC) drastically alters the biological identity of the particles. Adsorbed …

Aicropcam: Deploying Classification, Segmentation, Detection, And Counting Deep-Learning Models For Crop Monitoring On The Edge, Nipuna Chamara, Geng (Frank) Bai, Yufeng Ge

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Precision Agriculture (PA) promises to meet the future demands for food, feed, fiber, and fuel while keeping their production sustainable and environmentally friendly. PA relies heavily on sensing technologies to inform site-specific decision supports for planting, irrigation, fertilization, spraying, and harvesting. Traditional point-based sensors enjoy small data sizes but are limited in their capacity to measure plant and canopy parameters. On the other hand, imaging sensors can be powerful in measuring a wide range of these parameters, especially when coupled with Artificial Intelligence. The challenge, however, is the lack of computing, electric power, and connectivity infrastructure in agricultural fields, preventing …

Determining The Presence And Size Of Shoulder Lesions In Sows Using Computer Vision, Shubham Bery, Tami M. Brown-Brandl, Bradley T. Jones, Gary A. Rohrer, Sudhendu Raj Sharma

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Shoulder sores predominantly arise in breeding sows and often result in untimely culling. Reported prevalence rates vary significantly, spanning between 5% and 50% depending upon the type of crate flooring inside a farm, the animal’s body condition, or an existing injury that causes lameness. These lesions represent not only a welfare concern but also have an economic impact due to the labor needed for treatment and medication. The objective of this study was to evaluate the use of computer vision techniques in detecting and determining the size of shoulder lesions. A Microsoft Kinect V2 camera captured the top-down depth and …

Performing Motorized-To-Non-Motorized Crash Analysis Using Multi-Model Lbs Traffic Data Calibrated Through Random Forest Models, Nicholas Aldridge

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

Traditionally, traffic prediction has been an engineering challenge due to insufficient quantities of data. In this thesis, the use of a new type of data called location-based service (LBS) data from StreetLight (StL) and a large database of multi-modal traffic counts are used to infer vehicle, pedestrian, and bicycle volumes on all road segments in Lincoln, Nebraska. Additional land use features are incorporated into the model from the EPA Smart Location Database (EPA-SLD). The use of random forest models provides strong measures of fit for all modes, with R² scores of 0.98 for both the bicycle and pedestrian modes …

Bridge Deck Overhang Design: Effective Vehicle Impact Loads, Ultimate Strength, And Implications On Bridge Rail Performance, Andrew Eric Loken

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

When an errant vehicle strikes a bridge railing on a typical girder bridge, impact loads are transmitted downward through the railing and inward through the deck overhang to the primary superstructure elements. In this research effort, design demands for deck overhangs supporting concrete railings were characterized using physical testing and complementary modeling in LS-DYNA. Physical test and modeling results were also used to better characterize the ultimate strength of overhangs supporting post-and-beam railings. Ultimately, a novel design methodology for deck overhangs was developed and proposed for adoption to the AASHTO LRFD Bridge Design Specifications (BDS).

For overhangs with solid concrete …

An Icfd Fluid Model Used In A Mash Tl-6 Vehicle Model, Md Zunayed Habib

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

The objective of this thesis was to develop an ICFD finite element model of a partially filled deformable container suitable for impact scenarios. This model will be later incorporated into the existing TL-6 vehicle model, which is a tractor-tank trailer vehicle model. Previous finite element fluid models for the TL-6 vehicle used an elastic fluid model, which could not predict the fluid behavior correctly.

A study was conducted on the ICFD modeling and an improved ICFD model has been developed using the LS-DYNA, a finite element analysis software. Different properties and parameters of the fluid and the container were adopted …

Characterization Of Interlayer Laser Shock Peening During Fused Filament Fabrication Of Polylactic Acid (Pla), Fabien Denise

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

The field of additive manufacturing (AM) has gained a significant amount of popularity due to the increasing need for more sustainable manufacturing techniques and the adaptive development of complex product geometries. The problem is that AM parts routinely exhibit flaws or weaknesses that affect functionality or performance. Over the years, surface treatments have been developed to compensate certain flaws or weaknesses in manufactured products. Combining surface treatments with the modularity of additive manufacturing could lead to more adaptable and creative improvements of product functions in the future. The current work evaluates the feasibility of pursuing a new research axis in …

Experimental Analysis Of Nonlinear Wave Propagation In Bistable Mechanical Metamaterials With A Defect, Samuel R. Harre

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

Mechanical metamaterials built up of compliant units can support the propagation of linear and nonlinear waves. A popular architecture consists of a one-dimensional chain of bistable elements connected by linear springs. This type of chain can support nonlinear transition waves that switch each element from one stable state to the other as they propagate along the chain. One way to manipulate the propagation of such waves is via introduction of a local inhomogeneity, i.e., a defect in the otherwise periodic chain. Recent analytical and numerical work has shown that based on its initial velocity, a transition wave may be reflected, …

Amorphous Boron Carbide-Amorphous Silicon Heterojunction Devices, Vojislav Medic

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

This dissertation will show successful development and characterization of amorphous boron carbide-amorphous silicon heterojunction device with potential for neutron detection.

The amorphous hydrogenated boron carbide (a-BC:H) has been extensively researched as a semiconductor for neutron voltaic device fabrication. Naturally occurring boron contains 19.8% of boron isotope B¹⁰ that has a high absorption cross section of thermal neutrons at lower energies, and boron carbide contains 14.7% of that B¹⁰ isotope. Therefore, as a semiconductor compound of boron a-BC:H has the ability to absorb radiation, generate charge carriers, and collect those carriers.

Previous work on a-BC:H devices investigated the fabrication …

Measurements Of Azimuthal Anisotropy Of Nonprompt D0 Mesons In Pbpb Collisions At √𝑠Nn = 5.02 Tev, A. Tumasyan

Department of Civil and Environmental Engineering: Faculty Publications

Measurements of the elliptic (𝑣₂) and triangular (𝑣₃) azimuthal anisotropy coefficients are presented for D⁰ mesons produced in b hadron decays (nonprompt D⁰ mesons) in lead-lead collisions at √ 𝑠_NN = 5.02 TeV. The results are compared with previously published charm meson anisotropies measured using prompt D⁰ mesons. The data were collected with the CMS detector in 2018 with an integrated luminosity of 0.58 nb⁻¹. Azimuthal anisotropy is sensitive to the interactions of quarks with the hot and dense medium created in heavy ion collisions. Comparing results for prompt and …

An Autoencoder‑Based Snow Drought Index, Sinan Rasiya Koya, Kanak Kanti Kar, Shivendra Srivastava, Tsegaye Tadesse, Mark Svoboda, Tirthankar Roy

Department of Civil and Environmental Engineering: Faculty Publications

In several regions across the globe, snow has a significant impact on hydrology. The amounts of water that infiltrate the ground and flow as runoff are driven by the melting of snow. Therefore, it is crucial to study the magnitude and effect of snowmelt. Snow droughts, resulting from reduced snow storage, can drastically impact the water supplies in basins where snow predominates, such as in the western United States. Hence, it is important to detect the time and severity of snow droughts efficiently. We propose the Snow Drought Response Index or SnoDRI, a novel indicator that could be used to …

Mechanisms And Opportunities For Rational In Silico Design Of Enzymes To Degrade Per- And Polyfluoroalkyl Substances (Pfas), Melissa Marciesky, Diana S. Aga, Ian M. Bradley, Nirupam Aich, Carla Ng

Department of Civil and Environmental Engineering: Faculty Publications

Per and polyfluoroalkyl substances (PFAS) present a unique challenge to remediation techniques because their strong carbon−fluorine bonds make them difficult to degrade. This review explores the use of in silico enzymatic design as a potential PFAS degradation technique. The scope of the enzymes included is based on currently known PFAS degradation techniques, including chemical redox systems that have been studied for perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) defluorination, such as those that incorporate hydrated electrons, sulfate, peroxide, and metal catalysts. Bioremediation techniques are also discussed, namely the laccase and horseradish peroxidase systems. The redox potential of known reactants and …

Analyzing Major Elements Of Crash Injury Severity Involving Priority-I Detriments Of Vision-Zero Plan, Muhammad Umer Farooq, Cole Madson, Aemal Khattak

Mid-America Transportation Center: Final Reports and Technical Briefs

Road traffic crashes result in significant economic losses for individuals, their families, and entire nations. These losses stem from the expenses associated with injury treatment, as well as the productivity lost due to fatalities or disabilities caused by these injuries. The 2030 Agenda for Sustainable Development set an ambitious target of halving the global number of fatalities and injuries from road traffic crashes by 2020 and achieving zero deaths by 2030, commonly referred to as the 'Target Zero Plan.' The Target Zero Plan prioritizes traffic safety issues into three distinct levels. The three priority levels are determined based on the …

Exploring Statistical And Machine Learning-Based Missing Data Imputation Methods To Improve Crash Frequency Prediction Models For Highway-Rail Grade Crossings, Muhammad Umer Farooq, Aemal Khattak

Mid-America Transportation Center: Final Reports and Technical Briefs

Highway-rail grade crossings (HRGCs) are critical spatial locations of transportation safety because crashes at HRGCs are often catastrophic, potentially causing several injuries and fatalities. Every year in the United States, a significant number of crashes occur at these crossings, prompting local and state organizations to engage in safety analysis and estimate crash frequency prediction models for resource allocation. These models provide valuable insights into safety and risk mitigation strategies for HRGCs. Furthermore, the estimation of these models is based on inventory details of HRGCs, and their quality is crucial for reliable crash predictions. However, many of these models exclude crossings …

Road Work Zone Safety: Investigating Injury Severity In Motor Vehicle Crashes Using Random Effects Multinomial Logit Model, Aemal Khattak, Muhammad Umer Farooq

Mid-America Transportation Center: Final Reports and Technical Briefs

Work zones serve the purpose of facilitating maintenance and rehabilitation activities on roadways. However, these areas can also present unforeseen conditions to drivers, including narrowed right-of-way, lane shifts, and traffic disruptions. These conditions frequently contribute to vehicular crashes within work zones, resulting in property damage, injuries, and even loss of life. This paper aims to highlight work zone related crash data insights and presents statistical estimates of significant determinants of injury severity by analyzing ten-year crash data (2008-2018) from Nebraska, USA. The examination of crash data helped in highlighting work zone attributes that are empirically associated with serious injury crashes …