Engineering Commons^™

Acoustic And Ultrasonic Beam Focusing Through Aberrative And Attenuative Layers, Hossain Ahmed

Theses and Dissertations

Ultrasonic nondestructive evaluation (NDE) is a well-established technique to assess material properties and material state in noninvasive way. However, conventional NDE technologies are limited by the thick top coatings over the structure and, therefore, require time consuming removal and replacement of the coatings to perform the inspection. In biological application, although ultrasonic NDE is a safer method in compared to other radioactive non-invasive techniques, aberration of acoustic beams is more common as it encounters multiple tissue layers of complex geometry with nonhomogeneous properties. These limit the use of ultrasonic NDE in engineering and biological applications. To alleviate this problem, recently …

Development Of A Cfd Model For The Drying Of Aluminum-Clad Spent Nuclear Fuel, Nathaniel Cooper

Theses and Dissertations

The United States Department of Energy (DOE) currently manages approxi- mately 2500 metric tons of heavy metal (MTHM) of spent nuclear fuel (SNF), pri- marily from naval sources and domestic research reactors, and has agreements in place to accept 10,000 MTHM of aluminum-clad SNF from foreign reactors by 2029. However, due to the closure and the Yucca Mountain site and difficulties in the vitrification process, the majority of this fuel is expected to be placed in intermediate dry storage.

Before being placed in interim storage, all assemblies must be subjected to a drying process, either by forced gas recirculation (FGR) …

Steady-State And Transient Study Of Flow Boiling In Microchannels With Microgrooves/Micronozzles, Congcong Ren

Theses and Dissertations

Microchannel flow boiling is one of the most desired cooling solutions for high power electronics. Owing to the high latent heat of vaporization, high heat fluxes can be achieved through phase-change heat transfer. However, the enhancements of (critical heat flux) CHF and heat transfer coefficient (HTC) are usually inhibited by the transitional flow patterns, which highly influence the liquid rewetting. In the past two decades, many techniques have been explored to enhance the liquid rewetting in microscale.

In this dissertation, four parallel micro-grooves fabricated on the bottom of five microchannels (W=200 μm, H=250 μm, L=10 mm) were designed to promote …

Exploration And Evaluation Of Novel Cathode Materials For Intermediate-To-Low Temperature Solid Oxide Fuel Cells, Chunyang Yang

Theses and Dissertations

Solid oxide fuel cells (SOFCs) have attracted considerable attentions due to its high conversion efficiency, fuel flexibility, and clean nature. However, the high cost and poor long-term stability induced by the high operating temperature (> 800 °C) of the conventional SOFCs hinder the further application. Therefore, lowering operating temperature to intermediate temperature range (IT, 650-800 °C) or even low temperature range (LT, 400-650 °C) is of practical importance for realizing SOFCs’ full commercial potential. Nevertheless, due to the large activation energy associated with oxygen reduction reaction (ORR), cathode polarization resistance becomes the dominate loss limiting SOFCs performance as operating temperature …

Artificial Intelligence Approaches For Structural Health Monitoring Of Aerospace Structures, Kimberly A. Cardillo

Theses and Dissertations

Structural health monitoring (SHM) and non-destructive evaluation (NDE) have been a significant research topic to help with damage detection in aerospace structures. SHM and NDE techniques are based on extracting damage sensitive features to determine the criticality of damage and lifetime of a structure. Acoustic emission (AE) signal detection is an important technique in SHM and NDE especially for fatigue crack growth. AE signals for thin aerospace structures consist of ultrasonic guided Lamb waves that propagate through the structure. This thesis focuses on AE signal repeatability, load at which AE signals occur, feature extraction, artificial intelligence and electro-mechanical impedance of …

Autonomous Drone-Based Sensor Package Deployment To The Underside Of Structures, Sabrina Rose Carroll

Theses and Dissertations

The objective of this project is to design, develop and experimentally test an Unmanned Aircraft System (UAS, commonly known as a drone) for the deployment of sensor packages to the underside of structures. This work begins with an in-depth review of existing automation techniques for various drone applications focusing on applications requiring interaction with the environment. Further reviewed is the impact of structures above the UAS during flight on the behavior of the aircraft.

Considering these topics, the development of a custom drone is presented to address the difficulties of delivering a package to the underside of a structure. Starting …

Evaluating The Effectiveness Of The Pedestrian Safety Intervention Program: Behavioral And Observational Approach, Deep Patel

Theses and Dissertations

Pedestrians are considered as the most vulnerable road users. On a nationwide scale, according to the National Highway Traffic Safety Administration, there were 6,075 pedestrian fatalities and more than 85,000 pedestrian injuries as a result of traffic crashes in 2017. This study provides national and state pedestrian fatality statistics, a systematic literature review of pedestrian injury severity, observational (video-based) & behavioral (survey-based) evaluation of the Street-Smart NJ pedestrian safety intervention campaign. Street-Smart NJ is a public education, awareness, and behavioral change campaign program that aims to improve pedestrian safety by increasing awareness of pedestrian safety risks and improving compliance with …

Evaluation Of Impact Of Fiber Type And Dosage Rate On Volumetrics And Laboratory Performance Of Asphalt Mixtures, Ahmad G. M. Alfalah

Theses and Dissertations

The purpose of this study is to evaluate the impact of fiber types, binder content, and dosage rates on the volumetric properties and laboratory performance of asphalt mixtures. One asphalt mixture (control) and four fiber types (Fiberglass, Basalt, Carbon, and Polyolefin/Aramid) were used to evaluate the impact of fiber types and dosage rates. Two mixing procedures for introducing fibers into asphalt mixtures were also evaluated: dry and proportional dispersion methods. To evaluate the impact of fiber types, 0.16% by total mix weight was used. Rutting, cracking, and durability performance tests were evaluated. Furthermore, using 0.15% and 0.3% fiber dosage rates, …

Epoxy-Functional Thermoplastic Copolymers And Their Incorporation Into Thermosetting Resins, Kayla Rose Sweet

Theses and Dissertations

While polymers have secured a place in the consumer, industrial, and military markets over the last seventy years, the next generation of polymers must become more renewable, more adaptive, and higher performing to bridge industrial needs and environmental gaps. To this end, unique network configurations of copolymers and interpenetrating polymer networks (IPNs) have been employed to combine features of two or more polymers into a single material that surpasses the sum of its parts. The customization of polymer networks can be made possible via dual-functional monomers, molecules characterized by two different reactive substituents that allow for versatile methods of polymerization. …

Synthesis And Characterization Of Thermosetting Epoxy Resins From Lignin-Inspired Phenolics, Kelli Marie Hambleton

Theses and Dissertations

The need for renewable polymers able to replace their petrochemical counterparts continues to grow as sustainability concerns constantly rise. Bisguaiacol, a bio-based alternative to bisphenol-A, has been synthesized using vanillyl alcohol and guaiacol via an electrophilic aromatic condensation. Purification provides both bisguaiacol and an oligomeric coproduct with a consistent number average molecular weight and dispersity of about 650 Da and 1.00, respectively, across multiple reaction volume scales. This coproduct has been well characterized as a low molecular weight novolac averaging 5 hydroxyls per molecule and was transformed into an epoxy resin suitable for use in thermosetting resin development. By utilizing …

Investigation Of An Avionics Part Deficiencies In Royal Saudi Air Force Fleets, Nasser S. Alanazi

Theses and Dissertations

The Royal Saudi Air Force (RSAF) is experiencing a shortage in certain avionics parts due to a lack of reliability. This issue is causing a supply chain disturbance in the F1-15 fleet and the Hawk fleet. One of the factors behind this problem is the environmental effects in Saudi Arabia .The study will investigate and analyze the methods for the Improvement Cycle Processes and the Quality Management within the RSAF repair cycle. Finding show that, the discrepancies are rising during summer and fall time due to the environment change, Other finding were addressed in the study.

3d Printing For Solving Part Obscolescence, Ayman G. Alqarni

Theses and Dissertations

The purpose of this research was to highlight the issue of parts obsolescence and to highlight the possibility of using alternative methods to overcome parts shortage. Specifically, this thesis sought to answer the research question: is the three-dimensional printing technology (3D) an applicable approach to overcome part obsolescence. The research question was answered through data research and survey analysis. Notwithstanding, the diminished manufacturing sources and material shortages (DMSMS) management and other existing approaches, such as forecasting, contracting, and reverse engineering (RE), were discussed briefly in the literature review and profoundly in chapter IV to differentiate among applicable existing solutions toward …

Operationalized Intent For Improving Coordination In Human-Agent Teams, Michael F. Schneider

Theses and Dissertations

With the increasing capabilities of artificial intelligent agents (AIAs) integrated into multi-agent systems, future concepts include human-agent teams (HATs) in which the members perform fluidly as a coordinated team. Research on coordination mechanisms in HATs is largely focused on AIAs providing information to humans to coordinate better (i.e. coordination from the AIA to the human). We focus on the compliment where AIAs can understand the operator to better synchronize with the operator (i.e. from the human to the AIA). This research focuses specifically on AIA estimation of operator intent. We established the Operationalized Intent framework which captures intent in a …

Survey Of Airflow Around A Heated Manikin As A Simulated Aeromedical Evacuation Patient On A Litter With Computational Fluid Dynamics Models, George P. Lemmer

Theses and Dissertations

Aeromedical Evacuations remain the predominant method used to transport patients from forward deployed areas of operations to secure locations with more robust medical infrastructure. Transportation of chemical warfare casualties and infectious patients require additional attention to prevent cross contamination. Specific airflow characteristics paired with environmental control system settings are a gap in scholarly literature. Based on the available literature computational fluid dynamics models were created to simulate the airflow around a patient represented by human geometry using commercially available software. In order to compare simulated and experimental results a heated manikin was placed in the MURPHEE aerosol exposure chamber and …

Analysis Of The Factors That Correlate With Transition Outcomes Of Commercial Technology Prototype Projects, Matthew D. Schoemaker

Theses and Dissertations

A key metric of success for Department of Defense (DoD) Research and Development organizations is the ability to transition technologies and prototypes. Office of the Undersecretary of Defense for Research and Engineering's prototyping guide shows successful transition pathways come in the forms of transition to operational use, rapid fielding, existing program adoption, or a new acquisition program (2018). There are many factors that occur throughout a prototype projects lifecycle that impact the likelihood of transition. These factors include both qualitative and quantitative factors. Limited research has been performed, past the best practice considerations, of what factors impact transition of prototyping …

Improving Closely Spaced Dim Object Detection Through Improved Multiframe Blind Deconvolution, Ronald M. Aung

Theses and Dissertations

This dissertation focuses on improving the ability to detect dim stellar objects that are in close proximity to a bright one, through statistical image processing using short exposure images. The goal is to improve the space domain awareness capabilities with the existing infrastructure. Two new algorithms are developed. The first one is through the Neighborhood System Blind Deconvolution where the data functions are separated into the bright object, the neighborhood system, and the background functions. The second one is through the Dimension Reduction Blind Deconvolution, where the object function is represented by the product of two matrices. Both are designed …

Aligning Performance Management Systems For Lasting Outcomes In Humanitarian Operations, Kalyn M. Howard

Theses and Dissertations

Logistics is dynamic, expansive, and critical to organizational success. While it is generally believed that effective logistics management is associated with positive performance outcomes, the links between organizational practice and performance are understudied. This dissertation leverages resource-based theory and organizational learning theory to examine organizational practice and performance in non-traditional logistics settings, with particular focus on military organizations and humanitarian operational settings. First, a meta-analytical study establishes generalizable associations between various operations management practices and performance outcomes. Then, this is applied to dynamic humanitarian logistics settings, exploring how practitioners perceive practice and performance, and how this is reported and documented …

Chronos Spacecraft With Chiron Probe: Exploration Of The Hydrosphere, Principle Satellites, Atmosphere, And Rings Of Uranus, Payton E. Pearson

Theses and Dissertations

A design reference mission using more modern technological innovations has been developed for exploration of the outer reaches of our Solar System, specifically Uranus and its system of satellites. This mission will utilize theoretical technologies mostly without regard to their current technological readiness level (TRL), though most systems have a TRL of at least 5. The primary innovations explored in this thesis are the new launch systems that provide far greater payload capacity potentially sent to anywhere in the Solar System, new Stirling-engine radioisotope thermoelectric generators (SRTGs), vastly improved data storage technologies, optimized satellite antenna relay of data using much …

Joint 1d And 2d Neural Networks For Automatic Modulation Recognition, Luis M. Rosario Morel

Theses and Dissertations

The digital communication and radar community has recently manifested more interest in using data-driven approaches for tasks such as modulation recognition, channel estimation and distortion correction. In this research we seek to apply an object detector for parameter estimation to perform waveform separation in the time and frequency domain prior to classification. This enables the full automation of detecting and classifying simultaneously occurring waveforms. We leverage a lD ResNet implemented by O'Shea et al. in [1] and the YOLO v3 object detector designed by Redmon et al. in [2]. We conducted an in depth study of the performance of these …

Investigation Of Factors Impacting A Helicopter Height-Velocity Diagram, Timothy A. Brown

Theses and Dissertations

A dynamic helicopter model was incorporated into an optimal control problem to determine minimal landing velocities. The solutions were determined using pseudospectral collocation methods as implemented by the GPOPS-II software. These solutions were then compiled to develop a HV diagram. An HV diagram displays regions of flight based on a helicopter's airspeed and height above the ground in which a safe landing would not be possible following engine failure. The applied methodology for constructing the HV diagram reduced issues involving solution convergence that was encountered in previous research. The influence of ground effect on the dynamic model was also investigated. …

Direct Digital Synthesis: A Flexible Architecture For Advanced Signals Research For Future Satellite Navigation Payloads, Pranav R. Patel

Theses and Dissertations

In legacy Global Positioning System (GPS) Satellite Navigation (SatNav) payloads, the architecture does not provide the flexibility to adapt to changing circumstances and environments. GPS SatNav payloads have largely remained unchanged since the system became fully operational in April 1995. Since then, the use of GPS has become ubiquitous in our day-to-day lives. GPS availability is now a basic assumption for distributed infrastructure; it has become inextricably tied to our national power grids, cellular networks, and global financial systems. Emerging advancements of easy to use radio technologies, such as software-defined radios (SDRs), have greatly lowered the difficulty of discovery and …

Image Processing And Classification Of Remotely-Sensed Satellite Imagery: An Application Towards Cloud Detection, Oluwamuyiwa Adesola Adeegbe

Theses and Dissertations

Atmospheric studies have been carried out for decades to forecast weather and climate trends such as tropical storms, etc. Of recent concern is the level of greenhouse gases in the atmosphere, which has a relative influence on the weather and climate trends. Over the years, large weather satellites like the GOES series have been used to monitor these GHGs. However, an in-depth understanding of the movement of these gases requires consistent monitoring, which has given rise to the need for miniaturized satellites. Since the miniaturized satellites are novel, they require a ground-truth like the GOES-16 satellite to validate these observations. …

Bioprinted In Vitro Model Of Human Glioblastoma, Rachel Lauren Schwartz

Theses and Dissertations

Glioblastoma multiform (GBM) is one of the most aggressive forms of primary brain tumors. GBM is fast progressing and resistant to treatment, resulting in a low survival rate. Conventional 2-dimensional tissue culture models cannot fully replicate the complexities of cancer lesions that contain multiple cell types and structures (e.g. vessels composed of endothelial cells, cancer cells, normal cells, etc.) as well as an intricate scaffold of proteins comprising the extracellular matrix (ECM). In addition, animal models cannot translate into the clinical disease in patients. Thus, this study has developed a bioprintable organ-on-a-chip (OOAC) model that mimics the important ECM factors …

Artificial Intelligence For Helicopter Safety: Head Pose Estimation In The Cockpit, Eric William Feuerstein

Theses and Dissertations

The recent impact of deep learning algorithms and their major breakthroughs on various aspects of our lives has led to the idea to investigate the application of these algorithms in different problem spaces. One of the novel areas of investigation is the aviation and air traffic control domain; as it offers a prime opportunity to enhance safety within the aviation community. Of particular importance to this community is improving the safety of rotorcraft operations, as this segment of the aviation industry is subject to a higher fatal accident rate than other segments of the industry. The improvement of safety for …

Improvements In Optical Trap Displays, R. Wesley Rogers

Theses and Dissertations

This thesis improves on the design of the Optical Trap Display (OTD), presented in 2018 [1]. Contributions include: real time animation; single beam, multiparticle suspension, point primitive anisotropic scattering, and virtual image approximation. First, real time animation was demonstrated on the OTD for the first time in full color at up to 30Hz refresh. Second, multi-particle systems allow for scaling of the display by a multiplicative factor, potentially up to orders of magnitude greater than the first OTD. Third, anisotropic scattering of point primitives was shown for individual suspended particles and multiple simultaneously suspended particles. Fourth, virtual images have been …

Novel Material For Advanced Tissue Regeneration, Karrer Mahdi Kadum Alghazali

Theses and Dissertations

Nerve tissue damage or failure can occur for various reasons, including infection, disease, aging, and trauma. The tissue microenvironment (extracellular matrix-ECM) plays a key role in regulating the self-renewal and recovery of damaged tissue. ECM-cell interactions govern cell migration and physiology, with biochemical and biophysical boundaries being the main factors that control ECM-cell interaction. Optimizing these boundaries for the recovering tissue will create a healthy microenvironment to support and enhance the recovery rate (1, 2). We have developed a novel, multidimensional nanocomposite system that incorporates gold nanorods (AuNRs) (aspect ratio of around 3) as an artificial ECM for cell adhesion, …

Laboratory Evaluation Of The Impact Of Additives On Asphalt Binders Used In Cold Regions, Neirouz Bouhrira

Theses and Dissertations

The objective of this research study is to evaluate the effect of additives (polymers, nanomaterials, and softening agents) on rutting, cracking, and fatigue performance of asphalt binders commonly used in cold regions (PG 52-34 and PG 64E-40). In this study, the first phase consisted of using polymers (Styrene-Butadiene-Styrene, Ground-Tire-Rubber) and nanomaterials (TiO2 and SiO2) to modify two asphalt binders used in cold regions (PG52-34 and PG64E-40). The second phase of the study consisted of adding a combination of softening agents (Corn oil or Sylvaroad) with polymers (SBR, Epoxy, and SBS) to PG52-34 asphalt binder. The performance evaluation was conducted using …

Modular 3d Printer System Software For Research Environments, Clayton D. Ramstedt

Theses and Dissertations

The Nordin group at Brigham Young University has been focused on developing 3D printing technology for fabrication of lab-on-a-chip (microfluidic) devices since 2013. As we showed in 2015, commercial 3D printers and resins have not been developed to meet the highly specialized needs of microfluidic device fabrication. We have therefore created custom 3D printers and resins specifically designed to meet these needs. As part of this development process, ad hoc 3D printer control software has been developed. However, the software is difficult to modify and maintain to support the numerous experimental iterations of hardware used in our custom 3D printers. …

Gradient-Based Layout Optimization Of Large Wind Farms: Coupled Turbine Design, Variable Reduction, And Fatigue Constraints, Andrew P. J. Stanley

Theses and Dissertations

Wind farm layout optimization can greatly improve wind farm performance. However, past wind farm design has been limited in several ways. Wind farm design usually assumes that all the turbines throughout the farm should be exactly the same. Oftentimes, the location of every turbine is optimized individually, which is computationally expensive. Furthermore, designers fail to consider turbine loads during layout optimization. This dissertation presents four studies which provide partial solutions to these limitations and greatly improve wind farm layout optimization. Two studies explore differing turbine designs in wind farms. In these studies, Wind farm layouts are optimized simultaneously with turbine …

Modeling And Effects Of Non-Homogeneous Infiltration On Material Properties Of Carbon-Infiltrated Carbon Nanotube Forests, Daniel Owens Snow

Theses and Dissertations

This work investigates the material properties and production parameters of carbon infiltrated carbon nanotube structures (CI-CNT's). The impact of non homogeneous infiltration and the porosity of cross section regions, coupled with changes in designed geometry, in this case beam width, on the density and modulus of elasticity are compared. Three potential geometric models of beam cross section are proposed and evaluated. 3-point bending, SEM images, and numerical optimization are used to assess the validity of each model and the implications they have for future CI-CNT material applications. Carbon capping near exterior beam surfaces is observed and determined to be a …