Engineering Commons^™

Thermal Hydraulic Analysis For Different Subchannels Of Generic Vver-1200, Mosaddak Ahamed Zahid, Md. Imam Mehedi, Shamsul Arefin Shibly, A. S. Mollah

International Journal of Nuclear Security

The demand for nuclear energy is steadily increasing all over the world. Most nuclear power is used for peaceful applications such as power generation, healthcare, agriculture, food security, industry, and research. One of the primary applications of nuclear energy is the generation of electricity through nuclear power plants based on nuclear reactors. Many developing countries around the world (such as Bangladesh) are moving toward nuclear power plants because they have huge advantages, including low-cost energy, reliable energy sources, zero carbon emissions, and high energy concentration. As a result, the demand for nuclear reactor protection and operational protection of nuclear power …

Deformation Demands And Collapse Performance Of Seismically Detailed Concentrically Braced Frames, Samuel Jablonsky

Master's Theses (2009 -)

Special concentrically braced frames (SCBFs) and ordinary concentrically braced frames (OCBFs) are seismic-force-resisting systems often used in steel building construction. Previous research has shown that lower brace width-to-thickness ratios delay brace fracture during cyclic inelastic loading that is typical during moderate-to-large earthquakes. To ensure adequate seismic performance, SCBF and OCBF brace shapes are thus limited by the highly and moderately ductile width-to-thickness ratio limits, respectively, presented by the American Institute of Steel Construction Seismic Provisions for Structural Steel Buildings. To justify these limits, system-level analysis of SCBFs and OCBFs during high seismic events is needed. This study uses nonlinear response-history …

New Improvements To Defend Against Power Analysis Attacks In Ijtag Access Protocol, Haoran Wei

Computer Science and Engineering Theses and Dissertations

More and more instruments are now integrated on the chip for testing, debugging, monitoring, and post-silicon validation. IEEE Std 1687 (IJTAG) provides efficient access to these instruments. At the same time, techniques for an attacker to steal important data through the IJTAG network have also emerged. To improve the security of the IJTAG network and especially the communication between software and a board, others have proposed a security access protocol with several possible implementations based on an information hiding method. For example, one version of this previously published bidirectional authentication access protocol uses multiple templates to embed keys to improve …

Laboratory Evaluation And Field Demonstration Of Cold In-Place Recycling Asphalt Mixture In Michigan Low-Volume Road, Dongzhao Jin, Lei Yin, Lance Malburg, Zhanping You

Michigan Tech Publications

Cold-in place recycling (CIR) is a promising technology for the rehabilitation of asphalt pavements. However, the CIR asphalt pavement constructed in the field often has high air voids due to the presence of moisture during construction, and the moisture susceptibility of the pavement is crucial in determining its service life. Therefore, the objective of this research was to assess the laboratory performance of CIR asphalt mixes under freeze-thaw conditions (The mix prior to being subjected to freezing and thawing is labeled as "dry condition", while the mix that was placed in a refrigerator at –18 °C for 16 h and …

Freezing-Thawing Hysteretic Behavior Of Soils, Jidong Teng, Antai Dong, Sheng Zhang, Xiong Zhang, Daichao Sheng

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The soil freezing characteristic curve (SFCC) plays a crucial role in investigating the soil freezing-thawing process. Due to the challenges associated with measuring the SFCC, there is a shortage of high-quality or rigorous test results with sufficient metadata to be effectively used for applications. Current researchers typically conduct freezing tests to measure the SFCC and assume a singular SFCC when studying the freezing-thawing process of soils, although limited studies indicated that there is a hysteresis during the freezing and thawing process. In this paper, a series of freezing-thawing tests were performed to assess the SFCC, utilizing a precise nuclear magnetic …

Balloon Borne Gps-Enabled Radiosondes That Enable Simultaneous Multi-Point Atmospheric Sensing With A Single Ground Station, Peter A. Ribbens

Doctoral Dissertations and Master's Theses

Radiosondes are balloon borne atmospheric instruments that are a critical tool for understanding dynamics in the lower layers of the atmosphere. The low-cost radiosondes developed in the Space and Atmospheric Instrumentation Lab have been further developed to improve the system's use as a science-quality atmospheric instrument that is unique in its ability to simultaneously track multiple sondes with a single ground station. Sensors to measure temperature and pressure were added to improve measurements of the atmospheric state. A printed circuit board shield and 3D-printed shell were designed to make mass manufacturing possible. A thermistor-based temperature sensor was developed and tested …

Optimization Of A Plate Beam System For Energy Harvesting Using A Piezoelectric Material, Jose Manuel Almendros Espantaleon

Doctoral Dissertations and Master's Theses

With a continuously growing demand for power, driven by the need to reduce our environmental footprint, this research provides an examination of the potential of energy harvesting with smart materials technology and its practical applications. The energy harvesting system considered here works on generating energy through vibrations of a piezoelectric material beam which will undergo sustained vibrations due to flow of air over its surface. It is assumed that sustained limit cycle oscillations of this system will occur at the flutter velocity. This research creates an optimization framework to obtain the best values of parameters that will result in the …

Exploring A New Conceptual Framework In Aviation Maintenance Incident Reporting Using Natural Language Processing, Christopher P. Braun

Doctoral Dissertations and Master's Theses

In the analysis of human error incidents, human factors specialists predominantly follow two schools of thought in categorization strategies. One is to categorize the operator’s actions by the physical properties of the activity (phenotypes); the other focuses on the cognitive behaviors preceding the incident (genotypes). These categorization strategies are intended to foster an understanding of the events, identify risks, and assist in the implementation of risk reduction interventions. Commercial aviation maintenance presents unique challenges to human factor practitioners in terms of task requirements, working environments, communication modalities, and safety standards. Complex tasks are handed from one shift of personnel to …

Situation Awareness Assessment Of Enhanced Stable Approach Flight Instrument Displays, David J. Hunter

Doctoral Dissertations and Master's Theses

Through the year 2022, runway-related events, including excursions, abnormal runway contact, and runway undershoot and overshoot, were the third leading causes of fatal aircraft accidents. Principal to these runway-related accidents was the presence of an unstable approach. Pilots currently must depend on the timely recall of stable approach criteria stored in long-term memory, application of those criteria against current flight conditions, perception and cognition of deviation from those criteria, and determination of potential courses of action. Such recall is fallible, and challenges to perception and cognition are ever-present.

This study examined whether the presentation of stable approach criteria boundaries and …

Assessing The Impact Of Spacecraft Fragmentation In The Cislunar Region, Marta Lopez Castro

Doctoral Dissertations and Master's Theses

In the last decades, space missions have followed great advancements due to technological improvements and the extensive research developed in the field. Some of these missions are increasingly focusing on satellites orbiting the Moon. The Cislunar region is known to have a higher non-linear chaotic component in the dynamics compared to the low-Earth environment. This research is focused on studying the impact that a satellite explosion has in the Cislunar vicinity. The study is conducted for different periodic orbits that are key destinations for Cislunar traffic. By varying the initial conditions, simulations of explosions at different locations of the orbits …

Studying The Performance Of Object Recognition With Fusion Of Visible Light And Infrared Images With Neural Networks, Plamen Petkov

Doctoral Dissertations and Master's Theses

Neural networks have been used for object detection and recognition in both color and intensity camera images. As the use of infrared cameras, colloquially termed thermal cameras, has increased and costs have decreased, object detection and recognition in infrared camera images have been increasingly studied. An infrared image is treated as an intensity image, just like a grayscale camera image, except the intensity corresponds to infrared radiation instead of visible light. The information provided by these two types of images are different, especially in different lighting and environmental situations, and some types of objects are more easily recognized in visible …

Refinement Of A Regional Storm Surge Mesh For High-Resolution Topographic Representation Of Volusia County, Morgan Harbin

Doctoral Dissertations and Master's Theses

In 2022, Volusia and Flagler Counties of northeast central Florida were impacted indirectly by consecutive Hurricanes Ian and Nicole; the destabilization of dunes and armoring infrastructure caused by Ian left the region susceptible to Hurricane Nicole, which caused unprecedented coastal damage to dunes and seawalls. The extent of damage that occurred within Volusia and Flagler Counties during the 2022 hurricane season, the underrepresentation of this region within sustainability and resilience research, and the ecological, social, and economic value of the geography provide just cause for scientific inquiry of the area’s coastal dynamics. This thesis specifically describes an investigation of Hurricane …

Skilled Labor Shortage In Construction: Deep Dive Of Impactful Factors And Influential People Of The Decision-Making Process, Nicholas B. Hardy

LSU Doctoral Dissertations

The skilled labor shortage is well documented from a historical perspective via studies focusing on various construction trades such as carpentry, mechanical, electrical, plumbing, and tile setters. Causes of such shortages such as industry image, college as a preferred choice after high school, and construction being a last resort have been investigated extensively. Consequently, possible solutions ranging from amplifying shop classes in high school to intensifying recruiting efforts for union training programs have all been addressed throughout the last 40 years. However, recent studies have focused on identifying the magnitude and reach of the skilled labor gap while limited attention …

Multisensory System For Probing Scattering Media, Muralidhar Madabhushi Balaji

Electrical Engineering Theses and Dissertations

There are numerous problems in the physical sciences wherein the scattering of light fundamentally limits our ability to perceive and reason about objects within the visual field. Examples include navigation in foggy weather, detecting hidden contraband/explosives, detecting diseased regions in agricultural produce, and detecting tumors within tissue. In all these scenarios, the scrambling of light paths due to scattering reduces the ability to locate embedded objects and identify their spatial or spectral features.

Existing approaches address the challenge by augmenting optical sensing modalities with complementary techniques that do not rely on optical phenomenology, such as Magnetic Resonance Imaging (MRI) or …

Lessons From Developing A Rubric For Evaluating Need Statements On Health Technology Innovation Projects, L. Denend, R. Venook, R. D. Pamnani, K. Sheth, Joseph D. Towles

Engineering Faculty Works

In design-oriented biomedical engineering courses, some instructors teach need-driven methods for health technology innovation that use a “need statement” to reflect a student team’s hypothesis about the most fruitful direction for their project. While need statements are of the utmost importance to the projects, we were not aware of any comprehensive rubric for helping instructors evaluate them. Leveraging resources such as the Biodesign textbook along with input from faculty teaching health technology design at our university, we created a rubric for evaluating the construction of need statements. We then introduced the rubric to undergraduate students in a 3-week intersession course …

Poly(Thioether) Thermosets With Gated Photodegradation, Surabhi Jha

Dissertations

Photodegradable polymer networks are attractive due to the precise spatiotemporal control and large-area applicability of light. Chemical linkages that enable these polymer networks to be photo-responsive, also hinder their applicability in ambient light. Photostable and photodegradable networks have recently been reported to overcome this challenge by combining other stimuli with light for degradation. We report the design of a network that responds to a simultaneous, dual stimulus for photodegradation. We design poly(thioether acetal) networks with benzylidene acetal moieties that are known to undergo β-scission in the presence of free thiols. By blocking these free thiols with a thermally labile protecting …

Development Of A Large Format Additive Manufacturing System Based On An Off-The-Self Pellet Extruder, Aywan Das

Theses and Dissertations

Large Format Additive Manufacturing (LFAM), or Big Area Additive Manufacturing (BAAM), was introduced to resolve the limitations of the low deposition rate, low scalability, and therefore long print times, of traditional 3D printing methods when applied to the manufacturing of large structures and tooling. LFAM can be used to overcome the high conventional tooling costs of large structures. However, even with robotic setups, LFAM still mainly relies on quasi-planar, 2.5D printing strategies. This fails to reap the advantages of multi-axis printing, such as improved adhesion, reduced support material use, and the ability to create complex curved surfaces. In this research, …

Wind Plant Wake Losses: Disconnect Between Turbine Actuation And Control Of Plant Wakes With Engineering Wake Models, Ryan Scott, Nicholas Hamilton, Raul Bayoan Cal, Patrick Moriarty

Mechanical and Materials Engineering Faculty Publications and Presentations

Wake losses from neighboring plants may become a major factor in wind plant design and control as additional plants are constructed in areas with high wind resource availability. Because plant wakes span a large range of physical scales, from turbine rotor diameter to tens of kilometers, it is unclear whether conventional wake models or turbine control strategies are effective at the plant scale. Wake steering and axial induction control are evaluated in the current work as means of reducing the impact of neighboring wind plants on power and levelized cost of electricity. FLOw Redirection and Induction in Steady State (FLORIS) …

The Impact Of Pac-Loaded Polymer Membrane Thickness On Chloroform Removal And Comparison Of Solvent And Thermal Membrane Regeneration Methods, Yizhi Hou, Brooke K. Mayer

Civil and Environmental Engineering Faculty Research and Publications

Powdered activated carbon (PAC) has better adsorption performance than granular activated carbon (GAC) and is widely used in water purification. In most cases, PAC is dosed into water directly, then precipitated as sludge, and landfilled. In this study, PAC was mixed with a polymer and dissolved in dimethylformamide (DMF) solvent to form a PAC-loaded membrane, which was then tested for chloroform removal. The chloroform adsorption capacity of the PAC membrane increased with increasing membrane thickness because of higher carbon loading. However, regardless of membrane thickness, the flux of the PAC membranes was similar since flux resistance predominantly occurred at the …

Improving Tcp Performance Using P4-Programmable Data Planes, Jose Antonio Gomez Gaona

Theses and Dissertations

The Transmission Control Protocol (TCP) forms the foundation of reliable end-to-end communication and is widely used by many applications for efficient data transfers across the Internet. TCP relies on various congestion control algorithms (CCAs) to manage its response to network congestion. These algorithms ensure fairness among competing flows and optimize the use of available bandwidth. However, since TCP is deployed within end hosts, its capacity to attain visibility of network events is constrained. This limitation arises from the closed nature of non-programmable network devices, which prevents researchers from exploring customized actions in response to network events. Recently, the emergence of …

Dark Knights: Exploring Resilience And Hidden Workarounds In Commercial Aviation Through Mixed Methods, Riana Steen, James Norman, Johan Bergström, Gitte F. Damm

Aviation Faculty Publications

In this study, the duality of adaptive capacity in aviation safety is examined, where the need for resilience of frontline workers conflicts with the expectations and assumptions of upstream entities, leading to system brittleness. We explore three critical categories: responsibilization, the application of practical wisdom in navigating challenging situations, and the unrecognized sacrifices that accompany adaptation. A qualitative research design is used, using three focus groups consisting of pilots in a European airline, the airline’s safety department, and the respective civil aviation authority. The study's findings reveal i. significant organizational constraint and pressure on pilots, resulting in workarounds, personal playbooks, …

Electrical And Morphological Investigation Of A Fe(Ii) Based Spin Crossover Complex And Its Composite, Rifat Mahbub

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

Spin crossover (SCO) complexes have unique properties of switching their spin state upon perturbations like temperature, pressure, light, etc. Along with the spin state, different properties vary like structural, electrical, magnetic, optical properties. This enables these materials to be potentially used in various applications like molecular electronics, memory devices, switching devices, sensors and many more. To incorporate spin crossover materials into devices with efficient performance, the electrical behavior needs to be understood. This dissertation aims to investigate the effect of crystal structure on the electrical properties of iron(II) triazole spin crossover complex and how it can be modified for better …

Integrating Remote Sensing And Machine Learning To Determine Past, Current And Future Crop Water Use From The Nubian Sandstone Aquifer System, Moaz Ishag

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

The agriculture sector is a significant consumer of water, and sustainable water use begins with monitoring irrigated land. Delineating irrigated land supports decision-makers and promotes the sustainable use of this crucial resource. This study focuses on the Nubian Sandstone Aquifer System (NSAS), the largest aquifers in the world, which spans Egypt, Sudan, Libya, and Chad. The study aims to: 1) quantify the increase in irrigated hectares (both pivot and non-pivot) from 2000-2001 to 2023-2024; 2) identify major irrigated crop types and their water requirements; and 3) quantify groundwater crop water use from the NSAS using remote sensing via the Google …

Emulsion Liquid Membrane (Elm) Enhanced By Nanoparticles And Ionic Liquid For Extracting Vanadium Ions From Wastewater, Qusay Al-Obaidi, Nora Yehia Selem, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

Emulsion liquid membrane (ELM) stands out as an extraction process that has drawn much attention due to its promising prospects in industrial wastewater treatment technology. Nevertheless, the pivotal challenge is to reach high membrane stability to overcome the obstacle of applying ELM at the industrial scale. In this study, ELM was boosted by using nanoparticles (superparamagnetic iron oxide (Fe₂O₃)) in the stripping phase (W1) and ionic liquid (1-methyl-3-octyl-imidazolium-hexafluorophosphate [OMIM][PF6) in the oil phase (O) for recovering/extracting vanadium from synthetic wastewater to near completion and at the same time enhancing emulsion stability to be appropriate for industrial …

Induction Vacuum Swing Adsorption Over Magnetic Sorbent Monoliths And Extrudates For Ethylene/Ethane Separation, Khaled Baamran, Usman Shareef, Fateme Rezaei

Chemical and Biochemical Engineering Faculty Research & Creative Works

Electrification of adsorption processes is emerging as an adaptable solution for future gas separations. This study develops magnetic sorbent structures for use in induction vacuum swing adsorption (IVSA) process specifically designed for olefin/paraffin separation. Two sorbents, namely Fe₃O₄/ZIF-7 (ethane-selective) and Fe₃O₄/13X (ethylene-selective) were developed and formulated into extrudates (Fe₂₀/ZIF-7-P) and monoliths (Fe₂₀/13X-M), and tested under different regeneration scenarios, including simultaneous and subsequent induction-evacuation, induction only, and evacuation only. The dynamic adsorption results demonstrated that regeneration under subsequent induction-evacuation improves desorption rate and capability. Under this regeneration scenario, Fe …

Development Of A Rule-Based Monitoring System For Autonomous Heavy Equipment Safety, Amirpooya Shirazi

Department of Construction Engineering and Management: Dissertations, Theses, and Student Research

Roadway construction work zones are constantly exposed to interactions among construction equipment, workers, and vehicles. Furthermore, ensuring safety in these areas is considered a challenging task due to the complexity of the environment. As shown in the rising trend of fatal accidents in roadway work zones, current OSHA regulations in construction safety are insufficient in effectively detecting unsafe situations and mitigating the risks. Furthermore, best practices, such as internal traffic control planning (ITCP), exhibit critical limitations requiring continuous monitoring of active work zones as well as adjustments to the site coordination plans due to the dynamic nature of work zone …

Unmanned Aerial Vehicle (Uav)-Based High-Throughput Phenotyping For Maize Improvement, Eric T. Rodene

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

Modern breeding programs rely heavily on efficiently screening large numbers of genotypes for agronomic traits, such as disease resistance, drought tolerance, and yield. Identifying the genetic loci or genes associated with these traits using GWAS or functional analyses will benefit future plant breeding efforts seeking to incorporate these traits into new crop varieties, whether through conventional breeding or gene editing techniques. Unmanned aerial vehicle (UAV)-based image data has been increasingly used for this task, as it allows entire test plots to be quickly and cost-effectively phenotyped. In my research, I have developed methods to improve the accuracy of machine learning …

Growth And Simulation Of Dielectric-Metal Nanoheterostructured Thin Films By Ballistic Deposition, Shawn Wimer

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

This thesis is divided into two related topics: the structural and chemical characterization of dielectric-metal nanoheterostructured thin films grown by glancing angle deposition (GLAD) and the results of the simulated growth of films and structures by GLAD with discrete-space and continuous-space Monte Carlo ballistic simulation.

Individual structures comprising films grown by GLAD were investigated by S/TEM and SEM imaging, electron diffraction, and chemical characterization and mapping by EDX. Different intermolecular interactions within and between different materials, including Si, Ag, Au, and ZrO₂, are linked to differences in the shapes of individual materials in heterostructures, the shape of heterostructures …

Laser 3d Printing Of Diamond-Based Composite Materials For Thermal Management Applications, Nada Kraiem

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

With the trend towards miniaturization of electrical equipment and the constant increase in power density in semiconductor devices, efficient heat management has become a major concern for researchers. Indeed, this technological evolution imposes increasingly strict constraints in terms of thermal dissipation, necessitating innovative solutions to ensure better durability and reliability of components. In this context, the use of composite materials offering high thermal conductivity (TC) and low coefficient of thermal expansion (CTE) compared to pure metals has become essential to address overheating issues in electronic components.

The utilization of advanced materials such as diamond (D), with exceptional TC and hardness …

Advancements In Microscale Tensile Testing: A Novel Device For The High Throughput Analysis Of Two-Photon Polymerized Microfibers In Liquid, Grayson D. Minnick

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

Two-photon polymerization (TPP) enables the 3D fabrication of micro- and nanostructures from biocompatible materials with high resolutions, reaching into the realm of hundreds of nanometers. Such capabilities are crucial for advancing applications in fields like mechanobiology. As microscale technologies evolve, the precise characterization of material properties becomes increasingly essential. This is especially true for TPP-printed microstructures serving as scaffolds for 3D cell culture and intended for studying the mechanics of tissues. Despite the importance, traditional micro-scale tensile testing methods typically lack scalability and fail to replicate relevant environmental conditions. This dissertation introduces a new device that is specifically designed to …