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Articles 1 - 30 of 75
Full-Text Articles in Engineering
Characterization Of Friction At The Tool/Material Interface In Friction Stir Welding, Bryan Gonzalo Ramos Gonzales
Characterization Of Friction At The Tool/Material Interface In Friction Stir Welding, Bryan Gonzalo Ramos Gonzales
Theses and Dissertations
Friction Stir Welding (FSW) process development is very costly, and it is still experimental. A predictive model would optimize the weld by changing parameters and obtaining results that reflect the physical process. Friction is the primary adjustable parameter in FSW modeling. Currently, friction model selection is not physic-based. It is based on what is available and contributes to the best fit between the model and experimental data. The research objective is to characterize the interface tool/base material by studying the effect of tool friction coefficient and thermal properties. This is accomplished by changing welding parameters such as force, rpm, and …
Optimal Method To Obtain Soil Strength Properties In Sands For Laterally Loaded Pile Analysis In Lpile, Troy Roger Washburn
Optimal Method To Obtain Soil Strength Properties In Sands For Laterally Loaded Pile Analysis In Lpile, Troy Roger Washburn
Theses and Dissertations
One common software program developed for analyzing single laterally loaded piles is called LPILE. Soil properties are required as input into LPILE. For sands, the soil properties required are effective soil unit weight, γ’; subgrade modulus, k; and the internal friction angle, ϕ’. There are two commonly used methods to obtain ϕ’ and subsequently k: the API method and Bolton method. Fourteen different pile test sites were used in the analysis of the API and Bolton methods to obtain soil strength properties in sands for laterally loaded single pile tests. Between the fourteen pile test sites, a total of 26 …
Development Of Battery-Grade Silicon Through Magnesiothermic Reduction Of Halloysite-Derived Silica, Nathan Clarke
Development Of Battery-Grade Silicon Through Magnesiothermic Reduction Of Halloysite-Derived Silica, Nathan Clarke
Theses and Dissertations
The production of halloysite-derived silicon (HDS) is investigated as a potential anode material in lithium-ion batteries (LIBs). Other researchers have found HDS to be electrochemically active in small test cells. To test larger electrochemical cells, the production process needs to be scaled up and optimized. HDS is produced through magnesiothermic reduction of acid-etched halloysite. The reduction process is very exothermic and requires special consideration while being scaled up. A reactor and pressure release system were designed and fabricated to perform the reduction process in a safe manner. Various steps of the process were tested to determine their influence on the …
Void Formation And Mortality During Liquid Composite Molding, Jared Michael Turner
Void Formation And Mortality During Liquid Composite Molding, Jared Michael Turner
Theses and Dissertations
Within the high-performance composite manufacturing industry, there exists a need to improve the reliability of LCM (Liquid Composite Molding) manufacturing processes in producing composite parts that better approach the quality and consistency of pre-impregnated composite tapes that are cured in autoclaves with cost being a driving factor of this need. One obstacle to that end is the phenomenon of void formation during the LCM infusion processes. The formation of these voids through different mechanisms leads to composite parts with lower mechanical properties and consistency than their pre-impregnated autoclave cure counterparts. The objective of this research is to investigate the different …
Dam Failure And Incident Investigations, Nathaniel Gee
Dam Failure And Incident Investigations, Nathaniel Gee
Theses and Dissertations
There are multiple dam failures and dam safety incidents every year in the United States. There are currently no standard policy requirements for when or how to conduct failure or incident investigations. This paper first reviews one of the most significant failures in US history, the failure of Buffalo Creek Dam No. 3 in order to explore the impacts of one significant failure on dam safety policy in the US. The paper then explores the currents state of the industry by reviewing 58 different dam failure or incident investigation reports based on incidents that occurred in the United States from …
Pullout Strength Of Welded Wire And Ribbed Strip Reinforcement In Lightweight Cellular Concrete Backfill Behind Mechanically Stabilized Earth Wall, Mathew Robert Bueckers
Pullout Strength Of Welded Wire And Ribbed Strip Reinforcement In Lightweight Cellular Concrete Backfill Behind Mechanically Stabilized Earth Wall, Mathew Robert Bueckers
Theses and Dissertations
Lightweight cellular concrete (LCC) is a cement, water, and air entrained mixture that consists of 25-80% voids. The air voids reduce the material strength but also decrease the material weight. Due to its lightweight properties LCC is an attractive alternative to soil backfill for retained structures, such as mechanically stabilized earth (MSE) walls. Although LCC is widely used behind MSE walls, limited information exists regarding the pullout strength of MSE wall reinforcements in LCC backfill. This research attempts to fill the knowledge gap through performing pullout tests on welded wire and ribbed strip reinforcements in MSE walls to determine the …
Lcc Mse Walls, Joel Smith
Lcc Mse Walls, Joel Smith
Theses and Dissertations
Lightweight cellular concrete (LCC) is mainly a mixture of water, cement, and foam bubbles. LCC generally has a cast density between 20-60 pcf and an air content between 49-84%. LCC is often used as a fill material because it has a low unit weight which reduces settlement. LCC is increasingly being considered as a backfill behind Mechanically Stabilized Earth (MSE) walls and embankments. Although engineers are using LCC in MSE walls or free face walls (MSE wall without the concrete panels or reinforcements), there is presently a lack of information regarding the performance and behavior of LCC to guide them. …
A Tunable System For High Frequency Bioimpedance Plethysmography, Daniel H. Tebbs
A Tunable System For High Frequency Bioimpedance Plethysmography, Daniel H. Tebbs
Theses and Dissertations
Bioimpedance measurements are useful for determining a variety of biological conditions. By accounting for small impedance variations due to the arterial pulse, the effect of the blood can be studied more closely. The quasi-circulator system presented enables monitoring of pulsatile impedance changes with input frequencies above 1 MHz. The adjustable Rmatch allows for dynamic tuning of the system to increase sensitivity. By tuning Rmatch to be near the match point, the pulsatile signal in the output magnitude can be amplified, and tuning Rmatch to be at the match point causes the pulsatile signal in the output phase to be amplified. …
Evaluation Of Unmanned Aerial Vehicle Flight Parameters That Impact Stockpile Volume Computations, Nicole Marie Hastings
Evaluation Of Unmanned Aerial Vehicle Flight Parameters That Impact Stockpile Volume Computations, Nicole Marie Hastings
Theses and Dissertations
Stockpile volumes are monitored by their companies as the product (i.e., aggregate, soil) is moved in and out of the facilities to ensure minimal product loss. Companies are mandated to report product movement to the government to ensure that the aggregate and soil is going where it is supposed to go. Many tools are used to monitor stockpile volumes including truck scales (to weigh incoming and outgoing trucks), light detection and ranging (LiDAR), Global Navigation Satellite System (GNSS) equipment, and unmanned aerial vehicle (UAV) photogrammetry. These processes give a good estimate of stockpile volumes. Errors in these estimates typically come …
Dynamic Segmental Kinematics Of The Lumbar Spine During Diagnostic Movements, Paul Mcmullin
Dynamic Segmental Kinematics Of The Lumbar Spine During Diagnostic Movements, Paul Mcmullin
Theses and Dissertations
While lumbar kinematics can be measured in vivo, most measurements are invasive (such as percutaneous bone pins), provide high doses of radiation (such as biplane fluoroscopy), or are taken with the patient in a static position (such as MRIs). Recent work suggests that lumbar kinematics can be determined by dynamic measurements of epidermal strain in the lower back. This work aims to develop and examine a method of examining lumbar kinematics via optoelectronic motion capture utilizing skin-mounted markers in the lumbar region. Two studies were performed. One study examined lumbar epidermal strain in 28 asymptomatic subjects during diagnostic movements, while …
Combined Design And Dispatch Optimization For Nuclear-Renewable Hybrid Energy Systems, Daniel Clyde Hill
Combined Design And Dispatch Optimization For Nuclear-Renewable Hybrid Energy Systems, Daniel Clyde Hill
Theses and Dissertations
Reliable, affordable access to electrical power is a requirement for almost all aspects of developed societies. Challenges associated with reducing carbon emissions has led to growing interest in nuclear-renewable hybrid energy systems (N-RHES). Much work has already been done in suggesting and analyzing various N-RHES using a variety of optimization techniques and assumptions. This work builds upon previous techniques for simultaneous combined design and dispatch optimization (CDDO) for hybrid energy systems (HES). The first contribution of this work is the development and application of sensitivity analysis tailored to the combined design and dispatch optimization problem. This sensitivity analysis cover uncertainty …
Investigating The Effects Of Unfused Powder Damping In Laser Powder Bed Fusion, Samuel Hao Teng
Investigating The Effects Of Unfused Powder Damping In Laser Powder Bed Fusion, Samuel Hao Teng
Theses and Dissertations
This study uses Additive Manufacturing (AM) processes to fabricate 316L stainless steel beams with pockets of unfused powder for increased damping. Modal testing was completed to compare damping factors of beams with varying pocket geometries as well as number of pockets and pocket location. For the first three bending modes that were tested, an initial damping increase was observed when pocket height is greater than powder diameter. Following the initial increase there is a height threshold, which is mode dependent, that is required to achieve a statistically significant increase in damping.
Analysis And Simulation Of Nuclear Thermal Energy Storage Systems For Increasing Grid Stability, Jaron Wallace
Analysis And Simulation Of Nuclear Thermal Energy Storage Systems For Increasing Grid Stability, Jaron Wallace
Theses and Dissertations
With the growing capacity of renewable energy production sources, nuclear energy, once a mainstay of power generation, faces challenges due to its limited adaptability to fluctuating energy demands. This inherent rigidity makes it less desirable than the more flexible renewable sources. However, integrating thermal energy storage (TES) systems offers a promising avenue, enabling nuclear power plants (NPPs) to enhance their operational flexibility and remain competitive in an evolving renewable market. A comprehensive ranking methodology has been introduced, delineating the criteria and processes to determine the most synergistic TES/NPP design couplings. This methodology considers the unique characteristics of both current and …
A Series Of Improved And Novel Methods In Computer Vision Estimation, James J. Adams
A Series Of Improved And Novel Methods In Computer Vision Estimation, James J. Adams
Theses and Dissertations
In this thesis, findings in three areas of computer vision estimation are presented. First, an improvement to the Kanade-Lucas-Tomasi (KLT) feature tracking algorithm is presented in which gyroscope data is incorporated to compensate for camera rotation. This improved algorithm is then compared with the original algorithm and shown to be more effective at tracking features in the presence of large rotational motion. Next, a deep neural network approach to depth estimation is presented. Equations are derived relating camera and feature motion to depth. The information necessary for depth estimation is given as inputs to a deep neural network, which is …
Economy Of Scale Of Energy Intensity In Aquifer Storage And Recovery (Asr), Alyson Haley Rapp
Economy Of Scale Of Energy Intensity In Aquifer Storage And Recovery (Asr), Alyson Haley Rapp
Theses and Dissertations
More water utilities are adopting Aquifer Storage and Recovery (ASR) to balance long-term water supply and demand. Due to large implementation and operation costs, ASR projects need to be optimized, particularly for energy use, which is a major operating expense. This study examines the relationships among energy use, recharge, and recovery at two ASR projects in the western United States. The major finding is an economy of scale for recovery processes, but not for gravity-fed recharge processes. The economy of scale found is as follows: the energy intensity recovered decreases with volume. This suggests it is more energy-efficient to recover …
An Inexpensive, 3d Printable, Arduino And Bluray-Based, Confocal Laser And Fluorescent Scanning Thermal Microscope, Justin Loose
An Inexpensive, 3d Printable, Arduino And Bluray-Based, Confocal Laser And Fluorescent Scanning Thermal Microscope, Justin Loose
Theses and Dissertations
The Fluorescence Scanning Thermal Microscope (FSTM v3.0), was designed to create an inexpensive, and easily manufactured, device for measuring the diffusivity of samples with microscopic locational precision. This was accomplished by using a Blu-ray device known as a PHR-803T, referred to in this work as a PHR. The optics in the PHR are nearly identical in function to conventional devices used in thermoreflectance microscopy, making the PHR extremely useful to integrate into the FSTM design. The focus of this thesis is the application of the FSTM as a confocal microscope using 3D printed components and various low-cost devices to operate …
Using Jtag For External Scrubbing On The Amd Versal Acap, Michael L. Bjerregaard
Using Jtag For External Scrubbing On The Amd Versal Acap, Michael L. Bjerregaard
Theses and Dissertations
The Versal Adaptive Compute Acceleration Platform (Versal ACAP) is a system-on-chip (SoC) developed by AMD Xilinx. To help protect the programmable logic from soft errors, the configuration needs to be constantly checked and repaired through a process called scrubbing. This thesis provides a methodology for scrubbing the configuration over JTAG. The scrubber uses two platform device image (PDI) files, one to read the configuration and one to send corrected frames. The methodology is characterized to determine the time it takes to completely scrub the configuration. The designed scrubber was able to scrub the VM1802 in 11.5 seconds, or 41.6 Mbits/second, …
Modeling The Influence Of Vibration On Flow Through Embedded Microchannels, Joseph S. Seamons
Modeling The Influence Of Vibration On Flow Through Embedded Microchannels, Joseph S. Seamons
Theses and Dissertations
The influence of vocal fold (VF) vibration on perfused flow through VF vasculature is an area of research that has previously received limited attention. The aim of the research presented in this thesis was to contribute towards an improved understanding of the effects vibration on perfusion through vasculature within the VFs. This was done using a series of computational simulations of geometric changes to, and perfusion through, microchannels embedded in VF models. A computational structural model based on synthetic VF models used in previous experimental studies was first developed. The model and its embedded microchannel were initially studied under static …
Passive Positioning Using Linear Multilateration, Eric R. Widdison
Passive Positioning Using Linear Multilateration, Eric R. Widdison
Theses and Dissertations
Passive localization of aircraft in flight using signal time of arrival (TOA) poses some unique challenges. The sensors must be deployed in an approximately coplanar configuration, which produces significant vertical uncertainty in the estimated position. This dissertation examines the traditional algorithms used in passive localization. It presents general forms of linear TOA, time difference of arrival (TDOA), angle of arrival (AOA), and frequency difference of arrival (FDOA) equations from the literature and explains how to apply an intuitive geometric interpretation of these equations. It presents two novel algorithms for passive localization. One uses a one dimensional AOA (1AOA) to improve …
Heated Supersonic Jet Characteristics From Far-Field Acoustical Measurements, Matthew Austin Christian
Heated Supersonic Jet Characteristics From Far-Field Acoustical Measurements, Matthew Austin Christian
Theses and Dissertations
In the field of supersonic jet noise, measurements of full-scale afterburning jet engines are infrequent and provide unique opportunities to better understand jet noise phenomena. This thesis represents a phenomenological jet noise analysis using far-field noise data collected from a T-7A-installed GE F404-103 turbofan engine. One issue with the far-field acoustic data from the T-7A was the effects of ground reflections present in the spectra generated from the measured waveforms. A previously developed ground reflection model was implemented into the data to account for this interference. This work represents the first time this model has been implemented in data collected …
Malicious Game Client Detection Using Feature Extraction And Machine Learning, Spencer J. Austad
Malicious Game Client Detection Using Feature Extraction And Machine Learning, Spencer J. Austad
Theses and Dissertations
Minecraft, the world's best-selling video game, boasts a vast and vibrant community of users who actively develop third-party software for the game. However, it has also garnered notoriety as one of the most malware-infested gaming environments. This poses a unique challenge because Minecraft software has many community-specific nuances that make traditional malware analysis less effective. These differences include unique file types, differing code formats, and lack of standardization in user-generated content analysis. This research looks at Minecraft clients in the two most common formats: Portable Executable and Java Archive file formats. Feature correlation matrices showed that malware features are too …
Analysis Of Benefits Of Udot's Expanded Incident Management Team Program, Joel Clegg Hyer
Analysis Of Benefits Of Udot's Expanded Incident Management Team Program, Joel Clegg Hyer
Theses and Dissertations
In 2019, the Utah Department of Transportation (UDOT) funded a research study evaluating the performance measures of UDOT's expanded Incident Management Team (IMT) program. The number of IMTs patrolling Utah roadways increased from 13 to 25 between 2018 and 2020. Crash data were collected from the Utah Highway Patrol's Computer Aided Dispatch database and from the UDOT TransSuite database to compare IMT performance measures between the two years and to evaluate the benefits of the expanded IMT program. However, these data were compromised due to the effects of the COVID-19 pandemic. This study collected data for 2022 using the same …
Using Severity Weighted Risk Scores To Prioritize Safety Funding In Utah, Tomas Barriga Aristizabal
Using Severity Weighted Risk Scores To Prioritize Safety Funding In Utah, Tomas Barriga Aristizabal
Theses and Dissertations
Budgets for transportation improvements are limited so it is important for governments to focus on improving locations most in need of safety funding. The objective of the Two-Output Model for Safety (TOMS) is to provide the Utah Department of Transportation (UDOT) a reliable method to prioritize safety improvements on state-owned roadways among the different regions. This research will improve the existing Crash Analysis Methodology for Segments (CAMS) and Intersection Safety Analysis Methodology (ISAM) being used to analyze crashes on Utah roadways. The scope of this project is improving on the existing CAMS and ISAM to work together within R, to …
Nano Composite Piezo-Responsive Foam Enabled Pressure Mapping, Jake Duane Sundet
Nano Composite Piezo-Responsive Foam Enabled Pressure Mapping, Jake Duane Sundet
Theses and Dissertations
Pressure injuries cause pain both physically and financially. By creating a comfortable pressure mapping system, pressure injuries can more easily be prevented, and a large expenditure avoided. Nano composite piezo-responsive foam (NCPF) is an inexpensive foam that can be used to measure a static load while still providing a comfortable interface. As NCPF compresses, the impedance changes, correlating to a change in pressure. Optimizing electrode geometry is needed to take full advantage of the impedance change NCPF incurs upon deformation. To optimize electrode geometry, a design of experiment was performed which concluded that a one square inch area of interlaced …
Cooperative Navigation Of Autonomous Vehicles In Challenging Environments, Brendon Peter Forsgren
Cooperative Navigation Of Autonomous Vehicles In Challenging Environments, Brendon Peter Forsgren
Theses and Dissertations
As the capabilities of autonomous systems have increased so has interest in utilizing teams of autonomous systems to accomplish tasks more efficiently. This dissertation takes steps toward enabling the cooperation of unmanned systems in scenarios that are challenging, such as GPS-denied or perceptually aliased environments. This work begins by developing a cooperative navigation framework that is scalable in the number of agents, robust against communication latency or dropout, and requires little a priori information. Additionally, this framework is designed to be easily adopted by existing single-agent systems with minimal changes to existing software and software architectures. All systems in the …
Preparing For V2x Deployment: Evaluating Current Anonymity Implementations, And Developing A Framework For Gauging Roadside Unit Networkability, Daniel Arnaudov Sharp
Preparing For V2x Deployment: Evaluating Current Anonymity Implementations, And Developing A Framework For Gauging Roadside Unit Networkability, Daniel Arnaudov Sharp
Theses and Dissertations
In this thesis we answer two questions relating to the impending deployment of V2X. We answer, "What is the state of current privacy measures implemented to prevent tracking and promote anonymity?" We answer this by showing that tracking methods used to circumvent changing IDs are possible. We also show through conservative calculations that this problem will not go away on its own and requires direct effort. We also answer, "Is the available production V2X hardware ready for scalable deployment?" To do this we develop a framework for evaluating RSUs and many of their core functions related to deployment, scalability, and …
Interaction Of Natural Convection And Real Gas Radiation Over A Vertical Flat Plate, Nathan Hale
Interaction Of Natural Convection And Real Gas Radiation Over A Vertical Flat Plate, Nathan Hale
Theses and Dissertations
This study explores natural convection heat transfer and fluid flow from a vertical plate in a radiating gas accounting for real gas spectral behavior. Finite volume techniques are used to solve the coupled nonlinear partial differential equations for mass, momentum, and energy conservation, while radiation transfer is modeled using the Discrete Ordinates finite volume finite angle method. Real gas spectral behavior is accounted for using the Rank Correlated Spectral Line Weighted-sum-of-gray-gases method. It is found that gas temperature and velocity are higher in the boundary layer, thickening the thermal and hydrodynamic boundary layers compared to the limiting case of pure …
Designed For Better Control: Using Kinematic And Dynamic Metrics To Optimize Robot Manipulator Design, John R. Morrell
Designed For Better Control: Using Kinematic And Dynamic Metrics To Optimize Robot Manipulator Design, John R. Morrell
Theses and Dissertations
In the field of control theory, optimal performance is generally defined as the best possible controlled performance given a static, unchangeable plant system. However, principled design of the underlying system can make designing effective controllers easier and dramatically improve the final control performance beyond what any finely tuned controller could achieve alone. This work develops performance metrics for serial robot arms which help guide the design and optimization of the structure of the arm to achieve greater final performance. First, a kinematic (motion-based) metric called the Actuator Independence Metric (AIM) measures the uniqueness of the movement capabilities of the different …
Robust Localization And Landing For Autonomous Unmanned Aerial Vehicles In Maritime Environments, Alexander D. Jordan
Robust Localization And Landing For Autonomous Unmanned Aerial Vehicles In Maritime Environments, Alexander D. Jordan
Theses and Dissertations
This thesis presents methods for robust precision landing of unmanned air vehicles (UAVs) on platforms at sea. Localization methods are proposed for UAV-to-boat state estimation for systems that employ real- time kinematic (RTK) global navigation satellite system (GNSS) and vision sensors. Solutions for GNSS-only are first presented, followed by the fusion of GNSS and vision. The important problem of sensor intrinsic calibration is solved with a novel offline batch estimation approach. Hardware results are presented for all methods. Our calibration of GNSS-to-camera is shown to estimate sensor offsets with millimeter level accuracy. Localization systems are combined with custom state machines …
Real-Time Spatial Interference Removal And Maximum Ratio Combining In Communication Systems, Adam Gary Whipple
Real-Time Spatial Interference Removal And Maximum Ratio Combining In Communication Systems, Adam Gary Whipple
Theses and Dissertations
Radio frequency interference (RFI) is undesired and commonplace. Using a subspace projection method to spatially remove the interference from a phased array system gives results of a 30 dB interference null rejection (INR). Unmanned systems have been developed to observe underwater activity and communicate their observations to passing aircraft. These systems are currently limited by their use of a single transmitter. The uplink can be improved by using a dual-antenna beam steering approach to maximize the signal-to-noise ratio (SNR) the aircraft receives. This approach demonstrates an increase in SNR of 3 dB when compared to a single transmitter.