Engineering Commons^™

Nanoparticle-Based Approaches To Brain Injury And Studies For Improved Detectability Toward Better Delivery Characterization, Hunter A. Miller

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

The clinical translation of nanoparticle (NP) therapeutics for brain injury has been slow despite preclinical promise. The causes of disconnect between preclinical and clinical outcomes is multifactorial, but insufficient delivery is noteworthy. Preclinical delivery characterization often lacks, obscuring mechanisms of failure, slowing development. Multimodal imaging is a promising strategy to improve delivery characterization, combining the strengths of various modalities. Magnetic resonance imaging (MRI) and luminescence imaging are a suitable combination for multimodal imaging, expanding the spatial and temporal resolution of either alone, but further material development is needed to enhance detectability. One problem is the interference of cellular autofluorescence in …

Investigating Near-Field Radiative Heat Transfer With Titanium Carbide Mxenes And Slanted Columnar Thin Films, Sean Luke Murray

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

This work investigates the mechanisms to manipulate and control the magnitudes of Near-Field Radiative Heat Transfer (NFRHT) using two-dimensional materials and nanostructured surfaces. NFRHT occurs when the geometrical features of the radiating objects or the separation distance between interacting bodies are comparable to or lower than the characteristic thermal radiation wavelength. NFRHT magnitudes surpass the blackbody limit by several orders of magnitude due to phenomena such as photon tunneling and new modes of energy transfer, like surface polaritons. Therefore, it is crucial to understand how material properties and surface nanostructures affect NFRHT.

The first part of this work examines the …

Influence Of Aggregate Properties On Skid Resistance Of Pavement Surface Treatments, Alireza Roshan, Magdy Abdelrahman

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Skid resistance is a critical aspect for traffic safety since it significantly influences vehicle control and minimizes the distance required for emergency braking. The surface characteristics of pavements play a pivotal role in determining skid resistance. To achieve the optimal skid resistance performance, the pavement must sustain a specific level of friction. Thus, it is advantageous to apply surface treatments in areas that require enhanced friction. This study investigates the impact of factors such as the aggregate source, size, morphological properties, and abrasion levels on the skid resistance and frictional characteristics of a high-friction surface treatment (HFST). A complete investigation …

The Effectiveness Of Waste Tire Pyrolysis Oils (Wtpos) As Rejuvenating Agents For Asphalt Materials, Ahmed S. El-Ashwah, Magdy Abdelrahman

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The continuous increase in solid waste materials, such as waste tires, underscores the critical importance of recycling them to mitigate environmental impact and promote sustainable resource management. This research study evaluated the effectiveness of utilizing waste tire pyrolysis oils (WTPOs) as recycling agents for asphalt materials. The chemical composition and thermal behavior of WTPO were analyzed using Fourier transform infrared (FT-IR) spectroscopy and thermogravimetric analysis (TGA). Mechanically, the prepared WTPO binders were assessed by measuring dynamic viscosity and changes in high- and intermediate-temperature performance grades. Additionally, the cracking susceptibility of the binders was evaluated using the Glover-Rowe (G-R) parameter. The …

Indefinability Of Effective Stress For Unsaturated Soils, Xiong Zhang, Sandra Houston

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

For decades, researchers have searched for an unsaturated soil effective stress that performs analogously to effective stress for saturated soils and provides some simplifications over net stress and suction approaches. A recent debate is whether problems identified with unsaturated soil effective stress can be resolved via elastoplastic analyses. Effective stress equations are reviewed and categorized as being based on volume change, shear strength, yield, or degree of saturation. These equations are evaluated for consistency with saturated soil effective stress expectations using the Barcelona basic model (BBM), simplified into an integrated elastoplastic framework using the modified state surface approach (MSSA). Under …

Extrudability Window And Offline Test Methods To Predict Buildability Of 3d Printing Concrete, Yu Cun Gu, Kamal H. Khayat

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This Study Investigates the Effect of Thixotropy and Stiffness Evolution on the Extrudability and Buildability of 3D Printing Concrete. Different Types of Supplementary Cementitious Materials and Limestone Filler Were Used to Prepare Mortars with Varying Levels of Thixotropy and Early-Age Stiffness. Mixtures with Yield Stress and Flocculation (Τfloc) of 180–400 and 420–950 Pa, Respectively, Exhibited Adequate Extrudability Without Plastic Collapse. the Printing Was Completed 8–15 Min after Mixing at a Vertical Build-Up Rate of 138 Mm/min. Several Process Parameters, Including Rest Time to Secure a Penetration Resistance of 150 KPa (T150) and Penetration Resistance at Various Rest Times Were Developed …

Quantifying The Impact Of Technology Utilization On Schedule And Cost Performance In Construction Projects, Fareed Salih, Islam H. El-Adaway

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

There Has Been a Plethora of Research on the Performance of Schedule and Cost in Construction Projects. However, Current Research Falls Short in Investigating the Combined Contribution of Different Construction Technologies on Project Performance Metrics. Specifically, None of the Previous Efforts Have Used Integrated Earned Value Management (EVM) Parameters and Utilized Construction Technologies to Assess Project Schedule and Cost Performance. This Paper Fills This Knowledge Gap. to This End, a Multistep Research Methodology Was Employed to (1) Explore the Utilization Ratings of 13 Construction Technologies based on Data Collected from 52 Industry Experts; (2) Rank These Technologies in Terms of …

Rheology Modification Of Flowable Mortar With Co2, Sean Monkman, Soo Duck Hwang, Kamal Khayat

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The Rheological Properties of Mortar Samples with Different Additions of CO₂ during Mixing Were Determined. Flowable Cement-Based Mortars at Three Different W/c (0.55, 0.45 and 0.35) Were Produced and the Effects of CO₂ Gas Were Examined on the Fresh Properties of Slump Flow, Yield Stress and Plastic Viscosity. According to the Experimental Results, the Mortar Yield Stress and Plastic Viscosity Increased Faster over Time Than in a Reference System with the Increasing Addition of CO₂ and Greater Effects Were Seen at the Lowest W/c of 0.35 Than at the Others. the Impact of the CO₂ on …

Evaluation Of Manual Thermal Brake Screening Systems, Jeeyen Koo, David Leddy, Jennifer Walton

Kentucky Transportation Center Research Report

In 2021, manual thermal brake screening systems were installed at Lyon EB and Rowan County weigh stations. Two additional units were installed at Laurel SB and Scott County weigh stations the following year. Although this system is called a thermal brake screening system, its thermal camera images are used to find both brake and tire-related violations. At the time of this project, Lyon (EB), Rowan, and Scott County inspection locations also had tire pressure detection systems in addition to manual thermal brake screening systems. Both systems can be used to identify tire-related violations, but inspectors prefer to use the tire …

Virtual Engagement: Can Law Enforcement Benefit From Utilizing Extended Reality In Their Training Systems?, Jacob Maxwell Read

Electronic Theses and Dissertations

Introduction: Extended reality (XR) technologies offer innovative training solutions for various industries, including healthcare, manufacturing, aviation, sports, military, and law enforcement. XR can provide a solution for training where job tasks are difficult or near impossible to train in real-life. A human factors research and design approach could provide an effective, low-risk, and cost and time-efficient option for integrating the use of XR technology into training for many industries. To advance this goal, this research answered two main research questions: (1) What training needs/challenges are best suited for an XR training system designed for law enforcement officers (LEOs)? (2) …

Deep Reinforcement Learning-Based Dynamic Routing And Spectrum Access In Aeronautical Networks., Zhe Wang

Electronic Theses and Dissertations

As the airspace is experiencing an increasing number of aircraft, spectrum sharing among Air Vehicles (AVs) and Terrestrial Users (TUs) emerges as a compelling solution to improve spectrum utilization efficiency. I investigated three types of aeronautical communication including the single-hop Air-Air Communication Network (AACN), the multi-hop Air-Air Ad-hoc Network (AAAN), and the Aerial and Terrestrial Hybrid Network (ATHN). I assume a spectrum-limited scenario through all communication networks. Thus, the number of communication pairs is greater than that of the available channels, resulting in co-channel interference due to the reuse of the same channel among communication links. In a single-hop AACN, …

Epidural Stimulation For Urogenital Dysfunction In The Spinal Cord Injured Rat., Natasha Lorraine Wilkins

Electronic Theses and Dissertations

Spinal cord injury (SCI) is a devastating, life changing event that greatly impacts quality of life. SCI can have body-wide, multi-system consequences including dysfunction within the urogenital system. Challenges with the urinary system include urinary incontinence, urine retention, and detrusor-sphincter dyssynergia all of which require maintenance through the regular use of catheters. Sexual dysfunction in men, who comprise nearly 80% of the SCI population, includes erectile dysfunction, anejaculation, retrograde ejaculation, poor expulsive force during ejaculation, and poor sperm quality. The treatment for sexual function in SCI men is focused more on fertility through the collection of sperm for insemination procedures …

Constant-Ph Molecular Dynamics At Inorganic Interfaces: Adding A New Dimension To Simulations Of Interfacial Phenomena., Ted Kalbfleisch

Electronic Theses and Dissertations

This dissertation explores the application of novel molecular dynamics simulation methods to better understand complex systems, with a particular focus on silica materials and protein interactions. Silica materials, known for their versatile surface and solution chemistries, play critical roles in catalysis, chromatography, and wastewater treatment. Despite their widespread use, the molecular-level interactions between silica surfaces and their environments remain poorly understood. To address this knowledge gap, we employed λ-dynamics enabled constant pH molecular dynamics to dynamically model protonation and deprotonation events on silica surfaces. Traditional experimental techniques such as x-ray crystallography, NMR, and cryo-EM are inadequate for probing structures in …

Synergistic Strategies In Hybrid Mxed Matrix 3d Printing Of Thermoplastics & Thermosets: Design, Manufacturing, And Materials Development., Saleh Akram Khanjar

Electronic Theses and Dissertations

Composite manufacturing and mixed matrix structures have been produced using traditional manufacturing processes for various industrial applications due to their high mechanical properties to material weight and cost ratio. However implementation of composite and mixed matrix manufacturing with advanced manufacturing such as additive manufacturing is limited due to the hardware limitations of current 3d printing technologies and materials available for 3D printing applications. This work has developed and investigated a new hybrid 3D printing manufacturing process utilizing a variety of material systems (thermoplastic – thermoset, thermoplastic – thermoplastic, thermoset – thermoset, thermoplastic – thermoplastic – thermoset). This study developed thermoplastic …

Adaptive Robot Collaboration Using Robotic Skin And Motion Similarity., Jordan Dowdy

Electronic Theses and Dissertations

An essential part of robotics research is human-robot collaboration, which enables the use of current and new robots in everyday life and the workforce. This research applies to both parts of human-robot collaboration: physical human-robot interaction (pHRI), as well as non-physical human-robot interaction. The physical interaction uses tactile sensors and a Neuroadaptive Controller (NAC) to allow for the guidance of a robotic arm and its end-effector. The non-physical interaction uses a novel motion similarity metric, the Cartesian Segment Online Dynamic Time-Warping (SODTW), to allow a robot to better adapt to the speed of the user performing the motion during imitation …

Development And Processing Of Shape Memory Polymer Composites (Smpcs) For Application In Structural Robotics And Robotic Sensors., Kavish Sudan

Electronic Theses and Dissertations

Shape Memory Polymers (SMPs) have attracted significant attention since their introduction in the 1980s due to their remarkable ability to regain their original shape from a temporarily deformed state when exposed to an external stimulus, typically heat. This shape memory effect, driven by thermal transitions such as the glass transition temperature (T_g) or melting temperature (T_m), has made SMPs highly attractive for applications in soft robotics, aerospace, and biomedical devices. However, SMPs face challenges such as limited mechanical strength, thermal stability, and electrical conductivity, which hinder their broader adoption in advanced applications. To address these challenges, …

The Impact Of Internal Curing Additives On Compressive Strength, Shrinkage, And Internal Relative Humidity Of Mortars., Payton Scott

Electronic Theses and Dissertations

Curing is a critical step in concrete construction. When a concrete specimen is properly cured, its shrinkage and early age curling/warping can be reduced, and the concrete strength can be increased. Curing methods can be divided into two categories: traditional external curing and emerging internal curing methods. Internal curing has similar benefits to external curing, such as reduced early-age cracking and shrinkage risk, and increased durability and strength. The purpose of this research is to investigate internal curing additives and their impact on length change, weight change, compressive strength, autogenous shrinkage, and internal relative humidity. Mortar mixtures with lightweight aggregate …

Carboxen Micropreconcentrator Performance For Analyzing Btex In Air., Raymond Daniel Spargo

Electronic Theses and Dissertations

Volatile Organic Compounds (VOCs) are a class of toxic chemicals in environmental air associated with several serious health risks. Some of the most common and concerning VOCs are Benzene, Toluene, Ethyl Benzene, and Xylene (BTEX). To maintain healthy air quality in these environments, researchers pursue instruments and processes to quickly and accurately predict sub-ppb concentrations of BTEX in indoor and outdoor air. By employing a micropreconcentrator (μPC) to combine Solid-Phase Micro-Extraction (SPME) with Gas Chromatography Mass Spectrometry (GC-MS) analysis, trace BTEX content in air samples can be captured, extracted and analyzed. In this thesis, a dual-compartment μPC with Carboxen 1000 …

Accelerating The Circular Economy Transition: A Construction Value Chain-Structured Portfolio Of Strategies And Implementation Insights, Radwa Eissa, Islam H. El-Adaway

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Despite the Increasing Recognition of the Potential of Circular Economy (CE) Strategies, their Effective Application to Decarbonize the Construction Value Chain Faces Multiple Challenges. Ambiguity Surrounding CE, stemming from a Lack of Clarity on Actionable Strategies, is a Common Concern. Existing Studies Lack a Holistic Approach for Systematically Integrating CE Principles throughout the Construction Value Chain, resulting in a Scarcity of Information on How to Practically Adopt CE within Projects. This Research Aims to Accelerate CE Adoption by Creating a Value Chain-Structured Portfolio of CE Strategies and Analyzing the Implementation of Such Strategies in Actual Projects. to This End, a …

Development And 3d Printing Of Glass Fiber And Carbon Fiber Reinforced Shape Memory Polymer Composites For Structural Applications., Krishna Sai Aparna Munjuluri

Electronic Theses and Dissertations

This study aims at the development of shape memory polymer composites with two types of reinforcements, milled glass fibers, and chopped carbon fibers, for potential structural applications in aircraft and automotive industries. Glass fiber-SMP composites were made at fiber loading wt.% of 0%, 5%, 10%, and 20%. In contrast, carbon fiber-SMP composites were made at fiber loading wt.% of 0%, 5%, 10% and 15%. The feedstocks were extruded into filaments and characterized by their physical, rheological, chemical properties and morphologies. Fused Filament Fabrication 3D printing was used to manufacture specimens for mechanical testing of hardness and flexural properties. The findings …

Magnetic Sensor Compensation Utilizing Factor Graph Estimation, Frederic W. Lathrop, Clark N. Taylor, Aaron Nielsen

Faculty Publications

Recently, there has been significant interest in the ability to navigate without GPS using the magnetic anomaly field of the Earth (magnav). One of the key technical bottlenecks to achieving magnav is obtaining an accurate magnetic sensor calibration, taking into account own-ship and sensor effects. The Tolles-Lawson magnetic calibration method continues to be the industry standard and was developed when airborne magnetic survey aircraft were first employed over 70 years ago. In this paper, we present a magnetic calibration algorithm based on a factor graph optimization using inertial measurements as well as inputs from both a vector and scalar magnetometer. …

Effect Of Absorption Kinetics Of Superabsorbent Polymers On Printability And Interlayer Bond Of 3d Printing Concrete, Yu Cun Gu, Shuyi Zheng, Hongyan Ma, Wu Jian Long, Kamal H. Khayat

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This study examines the effect of the material characteristics of superabsorbent polymers (SAPs) on the printability and interlayer bond strength of 3D printing concrete. Three types of SAP, including two acrylamide-co-acrylic polymers with coarse and fine particle sizes (S1 and S2) and an acrylic copolymer (S3), were employed. The investigated mortar mixtures had a fixed initial mini-slump flow of 195 ± 10 mm and yield stress of 290 ± 25 Pa. The fluidity of SAP-incorporated mortars was maintained by either adjusting the superplasticizer dosage or increasing the water content. Test results indicate that particle flocculation is dependent on SAP absorption …

Carbon Capture And Renewable Energy Policies: Could Policy Harmonization Be A Puzzle Piece To Solve The Electricity Crisis?, Mahelet G. Fikru, Fateh Belaïd, Hongyan Ma

Economics Faculty Research & Creative Works

The electricity market crisis, driven by factors such as increased energy demand, rising fuel prices, aging infrastructure, and greenhouse gas emissions, requires a multifaceted approach including the strategic implementation of Carbon Capture and Storage (CCS) technologies, which despite high costs and potential adverse impact on renewable investments, can allow the use of fossil fuels to maintain grid stability, and simultaneously lower carbon footprint. Across the world, several nations are designing financial incentives and improving regulatory frameworks to reduce barriers to the deployment of CCS. However, it is not clearly understood whether and to what extent such policy support would affect …

Evaluation Of The Alveolar Crest And Cemento-Enamel Junction In Periodontitis Using Object Detection On Periapical Radiographs, Tai Jung Lin, Yi Cheng Mao, Yuan Jin Lin, Chin Hao Liang, Yi Qing He, Yun Chen Hsu, Shih Lun Chen, Tsung Yi Chen, Chiung An Chen, Kuo Chen Li, Patricia Angela R. Abu

Ateneo Laboratory for Intelligent Visual Environments

The severity of periodontitis can be analyzed by calculating the loss of alveolar crest (ALC) level and the level of bone loss between the tooth’s bone and the cemento-enamel junction (CEJ). However, dentists need to manually mark symptoms on periapical radiographs (PAs) to assess bone loss, a process that is both time-consuming and prone to errors. This study proposes the following new method that contributes to the evaluation of disease and reduces errors. Firstly, innovative periodontitis image enhancement methods are employed to improve PA image quality. Subsequently, single teeth can be accurately extracted from PA images by object detection with …

Nonplanar Robotic Printing Of Earth-Based Material: A Case Study Using Cob-Like Mixture, Lina Ahmad, Wassim Jabi, Marco Sosa

All Works

The study presents an integration of cob with robotic processes. By challenging conventional monolithic earth-building methods, the study proposes the use of spatial nonplanar formations that are robotically fabricated, presenting an alternative geometric language for earth construction. The research methodology is derived from existing factors within the robotic lab, encompassing both constant and variable parameters. Through an experimental approach, the variables are systematically manipulated while observing the outcomes to identify patterns and relationships. Incremental refinements to the research conditions result in an optimal equilibrium state within the defined lab parameters. An empirical investigation approach serves as the foundation for controlling …

Impacts Of High-Frequency Operation On Magnetics And Performance On Isolated Power Electronic Converter Design, David Arturo Porras Fernandez

Graduate Theses and Dissertations

The pursuit of high-power density and high switching frequency is a central theme in the advancement of power electronic converters. While these parameters offer significant benefits in terms of compactness and performance, they also introduce challenges related to efficiency and thermal management. This doctoral dissertation aims to provides a design framework to analyze the implications of high-frequency operation (> 100 kHz) on magnetics design and performance in power electronic converters, particularly when integrating silicon carbide (SiC) power modules. It examines the advantages and disadvantages of high-frequency operation and delves into its effects on the performance of the converter, focusing on …

High-Power Power Conditioning Systems For Medium-Voltage Applications, Ahmed Rahouma Fares Rahouma

Graduate Theses and Dissertations

The purpose of this dissertation is to address the background, theoretical analyses, design methodologies, and evaluation techniques relevant to high-power power conditioning systems (PCSs) tailored for medium-voltage (MV) applications. Conventional PCSs, reliant on line-frequency transformers (LFTs), suffer from many problems including low power densities, inflexible designs, and scalability constraints. Employing multilevel converters (MLCs), particularly cascaded H-bridge topology, eliminates the need for these LFTs. A key focus lies in minimizing the number of cascaded building blocks by harnessing MV power switching modules. The dissertation makes two primary contributions: firstly, it offers a design methodology for MV-PCS, facilitating the selection of the …

Evaluation, Modeling And Application Of Gallium Nitride Field Effect Transistor, Geno Guillaume

Graduate Theses and Dissertations

Gallium Nitride (GaN) has emerged as one of the leading materials for power devices due to its wide band gap and high electron mobility. The band gap is the minimum energy required to excite an electron up to a state in the conduction band where it can participate in conduction. Because of this, wide band gap (WBG) materials are favorable for various electrical applications. The market for GaN high-electron-mobility transistor (HEMT) is projected to exceed $1.25 billion by 2027. With the increase of market interest, modern technologies emerge that aim to push the boundaries of efficiency for GaN power devices. …

Feasibility Study For The Application Of A Solar Powered Absorption Chilling System For Cooling Poultry Houses In Northwest Arkansas, Matthew James Kelly

Graduate Theses and Dissertations

This paper investigates the economic feasibility of utilizing a solar-powered absorption chiller to provide cooling for poultry houses in northwest Arkansas. An existing thermodynamic model of a poultry house was modified to account for cooling. A simulation was performed using actual weather data from Fayetteville, Arkansas for 26 flocks of broilers at four cooling capacities for the 2020, 2021, and 2022 calendar years. Based on the simulation, the savings from reduced electricity use for ventilation and the cost of the required absorption chiller and solar thermal array for an 8-house farm were calculated. While providing cooling was found to reduce …

Modification Of Time-Domain Terahertz Spectroscopy System To Polarimetry Imaging System With Application To Human Breast Cancer Surgical Specimen, Nikita Gurjar

Graduate Theses and Dissertations

Breast-conserving therapy (lumpectomy) is one of the most performed breast cancer surgeries in the United States. The best outcome of lumpectomy surgery is achieved when the surgical margins are free of cancer. When remnants of cancer are detected at the surgical margins after the initial operation, a second operation will be required to remove the cancer. Unfortunately, a significant number of patients undergo breast conserving surgery (BCS) at local hospitals that do not have access to immediate on-site pathology leading to high rates of re-excision or reoperation (greater than 30%). Therefore, there is a significant need for new intraoperative technology …