Engineering Commons^™

Language As A Factor In Aviation Accidents And Serious Incidents: A Handbook For Accident Investigators Ed. 2, Elizabeth Mathews, Anthony T. Brickhouse, Joan Carson Ph.D., Enrique Valdes

Handbooks

The purpose of this handbook is to support accident investigators in the identification and consideration of possible language factors in aviation accidents and serious incidents. This handbook provides guidance, background information, and tools that will assist accident investigators in conducting a systematic review of possible language factors.

Machine Learning Framework For Nonlinear And Interaction Relationships Involving Categorical And Numerical Features, Shirish Mohan Rao

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

Traditionally, physical scientific experiments have been conducted extensively to study and understand the behavior of a process or a system. With the advancement of computing technology in recent years, computer codes and algorithms are used as simulators to replicate behavior of a complex system. Such use of computers to study a system is termed as ‘computer experiments.’ The process involves selecting specific points or runs in the design space in order to maximize information about the system in minimal runs. These computer models are high dimensional and can take a long time to simulate. Metamodels (or surrogate models) built using …

Multi-Player H1 Differential Game Using On-Policy And Off-Policy Reinforcement Learning, Peiliang An

Electrical Engineering Theses - Archive

This work studies a multi-player H-infinity differential game for systems of general linear dynamics. In this game, multiple players design their control inputs to minimize their cost functions in the presence of worst-case disturbances. We first derive the optimal control and disturbance policies using the solutions to Hamilton-Jacobi-Isaacs (HJI) equations. We then prove that the derived optimal policies stabilize the system and constitute a Nash equilibrium solution. Two integral reinforcement learning (IRL) -based algorithms, including the policy iteration IRL and o -policy IRL, are developed to solve the differential game online. We show that the off-policy IRL can solve the …

Wi-Fi-Based Indoor Localization Using Model-Based And Data-Driven Approaches, Ayoub Idelhaj

Electrical Engineering Theses - Archive

This thesis investigates model-based and data-driven approaches for indoor localization using the Received Signal Strength Indicator (RSSI) of Wi-Fi signals. We study multiple model-based indoor localization approaches, including the free space path loss model, the log-distance path loss model, the International Telecommunication Union (ITU) model, and a nonlinear regression model. We examine their indoor localization accuracy using raw RSSI values, and filter RSSI values passed through a Moving Average filter and a Kalman filter. For data driven approaches, we employ a family of Extreme Learning Machine (ELM) algorithms including Basic-ELM, Online Sequential-ELM (OS-ELM), Hierarchical-ELM (H-ELM), and Kernel-ELM (K-ELM), to find …

Mrda-Mgfsnet: Network Based On A Multi-Rate Dilated Attention Mechanism And Multi-Granularity Feature Sharer For Image-Based Butterflies Fine-Grained Classification, Maopeng Li, Guoxiong Zhou, Weiwei Cai, Jiayong Li, Mingxuan Li, Mingfang He, Yahui Hu, Liujun Li

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Aiming at solving the problems of high background complexity of some butterfly images and the difficulty in identifying them caused by their small inter-class variance, we propose a new fine-grained butterfly classification architecture, called Network based on Multi-rate Dilated Attention Mechanism and Multi-granularity Feature Sharer (MRDA-MGFSNet). First, in this network, in order to effectively identify similar patterns between butterflies and suppress the information that is similar to the butterfly's features in the background but is invalid, a Multi-rate Dilated Attention Mechanism (MRDA) with a symmetrical structure which assigns different weights to channel and spatial features is designed. Second, fusing the …

Development Of A Model To Prioritize Inspection And Condition Assessment Of Gravity Sanitary Sewer Systems, Karthikeyan Loganathan

Civil Engineering Dissertations - Archive

Underground utilities and wastewater collection systems deteriorate over time demanding utility owners to involve in continuous revisions and development of their asset management frameworks to maintain the functionality of their assets. In any asset management framework, inspection of an asset and respective condition assessment plays a vital role in successful operation and maintenance of systems. In the United States, closed-circuit television (CCTV) is the commonly used device for inspecting the inner environment of sewer pipes, which considering the large length of pipe inventory in a city, is a relatively expensive and time-consuming process. Therefore, inspection of every individual sanitary sewer …

Structural Performance Of Distressed Cast-In-Place Concrete Bridge Retaining Wall, Karzan Ms Habeeb

Civil Engineering Dissertations - Archive

Cast-In-Place (CIP) concrete retaining walls have been used in the United States widely in the 20th century. CIP concrete walls have additionally proven to be structurally rigid and cost-effective for low backfill height. This type of wall is also sustainable with design service life of 75 years (TxDOT 2014). However, during service, the wall undergoes distressed movements, structural deficiency, and stability related problems. CIP cantilever concrete retaining walls often do not perform as expected, and the walls are affected by construction and/or structural deficiency, which sometimes leads to failure. The current study was inspired by distressed CIP walls located on …

Modeling Of Hydrogen Sulfide Generation And Rates Of Microbial Induced Concrete Corrosion In Manhole Shafts, Sunakshi Hada

Civil Engineering Dissertations - Archive

Manhole shafts can undergo infrastructure failure due to microbially induced concrete corrosion (MICC). Deterioration of the sewer systems by MICC process occurs due to the volatilization of hydrogen sulfide into the gas phase. The volatized hydrogen sulfide gas reacts with oxygen to form sulfuric acid, resulting in concrete corrosion. If optimum conditions are present, 24 mm of concrete loss can occur in 31 months, and the cost of fixing can range from $10-$30 per square foot. Also, if the manholes are not properly maintained, they can cause serious safety hazards, such as manhole lids falling through the structure, streets giving …

Effectiveness Of Recycled Plastic Pin For Improving Bearing Capacity Of Embankment Over Soft Soil, Md Azijul Islam

Civil Engineering Dissertations - Archive

Construction of embankment over soft foundation soils is incredibly a challenging task due to the risk of bearing failure and excessive settlement of foundation soil. Most of the available conventional methods for addressing these problems are either expensive or time-consuming or both. Therefore, research has been striving to develop a sustainable alternative to the current conventional methods. A noble approach to improve the soft foundation soil could be the use of Recycled Plastic Pins (RPP) in combination with geosynthetics. The load transfer efficiency of a geosynthetic-reinforced and RPP supported embankment is influenced by interactions among embankment fill, geosynthetics, and foundation …

Development And Comparison Of Prediction Models For Sanitary Sewer Pipes Condition Assessment Using Multinomial Logistic Regression And Artificial Neural Network., Daniel Ogaro Atambo

Civil Engineering Dissertations - Archive

Sanitary sewer pipes infrastructure system in good condition is essential in providing safe conveyance of the wastewater from homes, businesses, and industries to the wastewater treatment plants. For sanitary sewer pipes to deliver the wastewater to the treatment plants, they must be in good condition. Most of the water utilities have aged sanitary sewer pipes. Water utilities inspect sewer pipes to decide which segments of the sanitary sewer pipes need rehabilitation or replacement. The process of inspecting the sewer pipes is described as condition assessment. This condition assessment process is costly and necessitates developing a model that predicts the condition …

Performance Of Recycled Plastic Pins For Increasing Bearing Capacity Of Foundation Soil, Faria Fahim Badhon

Civil Engineering Dissertations - Archive

Mechanically Stabilized Earth (MSE) walls constructed on unsuitable foundation soil are prone to large deformation and bearing capacity failure. A variety of techniques can be applied to address this issue, such as removal and replacement of existing soil with competent soil, staged construction, dynamic compaction, stone columns, geosynthetic reinforcement. One common traditional approach followed by Texas Department of Transportation (TxDOT) for the improvement of unsuitable foundation soil is removal of the in-situ soil and replacement with suitable fill material. However, this method can be time-consuming and expensive. A pile-supported system in combination with geosynthetic reinforcement can provide a sustainable solution …

Agent-Based Model Simulation For Police Deployment Decision-Making In Patrol Operations, Yasaman Ghasemi

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

Police patrolling plays a key role in responding to 911 calls and reducing crimes. The effectiveness of patrol operations heavily depends on the deployment of police officers – e.g., the number of officers assigned to specific policing districts or beats. The complex nature of the policing system – dynamic and stochastic criminal behavior, compounded with limited policing resources, render current (traditional) police operations, which are often managed in a reactive and stationary manner – often makes it very challenging to manage and control. This study develops an agent-based simulation framework to address the dynamically changing environment in police operations and …

Evaluating The Safety Cultures Of Kentucky Transportation Cabinet Maintenance Crews, Ashtarout Ammar, Zamaan Al-Shabbani, Hala Nassereddine, Chris Van Dyke, Gabriel B. Dadi

Kentucky Transportation Center Research Report

Highway work zones can be dangerous and unpredictable. Between 2003 and 2017, over 1,800 workers died on road construction sites. Eliminating injuries and deaths requires state transportation agencies to adopt robust safety cultures as there is a clear relationship between these cultures and worker behaviors. The Kentucky Transportation Cabinet (KYTC) is committed to improving safety performance by nurturing a positive safety climate among highway maintenance crews. To understand the safety cultures of KYTC maintenance crews, researchers administered a survey based on the Safety Climate Assessment Tool (S-CAT) developed by the Center for Construction Research and Training (CPWR). This is the …

A Mixed-Methods Approach To Explore Student Perceived Needs For Peer Mentorship In A College Of Engineering, Darcie Christensen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

“Nobody makes it alone. Nobody has made it alone” (NOVA SHRM & Dulles SHRM, 2012, p. 5). Mentoring generally has positive outcomes, such as increasing output, staying in work or school, increasing confidence, and others (Campbell & Campbell, 2007; Crisp & Cruz, 2009; Eby et al., 2008; NASEM, 2019; Pfund et al., 2016). This dissertation study focused on student perceived needs for peer mentorship in engineering, which can fill in gaps of traditional mentorship by pairing mentors and mentees at similar levels, increasing comfort and emotional support to mentees (Allen et al., 2017; Haggard et al., 2011; Kram & Isabella, …

Passive Cavity Deflation After Water Entry Facilitated By A Vented Tube, Emma R. Fraley

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

When an object enters water, a crater, or air cavity, can form around the object and remain attached as the object travels underwater. Cavities can be beneficial and reduce drag force but there may be times when the cavity needs to be removed. This research proposes a method to remove air cavities by letting air leave the cavity, deflating the cavity similar to how a balloon is deflated. To provide air a path to leave the cavity, a tube with vent holes is attached to the object. The vent holes are located near the object, where the air cavity forms, …

Venturi Meter Performance When Installed On The Branch Of A Tee Junction With Converging Run Flow, E. Elliot Naulu

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Venturi flow meters are often installed downstream of disturbances such as a tee junction, valve, or elbow. In such a case, a laboratory calibration may be needed to measure the Venturi meter’s performance under said limitations so that accurate metering is achieved. However, in some cases, laboratory calibration may not be possible.The purpose of this research was to investigate Computational Fluid Dynamics (CFD) ability to simulate a Venturi meter installed on the branch of a tee junction with converging run flow.

This study used CFD to compare against laboratory results to illustrate CFD’s capability as a calibration method. The results …

Development Of An Anisotropic Thermal Stress Model For A Low-Erosion Hybrid Rocket Nozzle System, Judson C. Stephens

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Hybrid rockets are rockets which employ a solid fuel grain with a liquid oxidizer. Hybrids have many promising potential applications, however they also have a few drawbacks. Of interest to this research is the increased rate of nozzle erosion inherent to hybrid rockets. In order to address this issue, a low-erosion nozzle is proposed and evaluated.

Evaluation Of Bioretention Performance In Northern Utah As A Function Of Media, Vegetation, And Loading, Trixie Rife

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Pollutants found in stormwater runoff are a growing environmental concern. The EPA has identified bioretention (BR) systems as a best management practice for the control of pollutants in stormwater runoff. BR systems reduce pollutant loads discharged to surface water bodies and to lower pollutant concentrations of water infiltrating into underlying groundwater. However, knowledge of the performance of BR systems in semi-arid Western climates is lacking. This study was conducted at three field sites in Northern Utah to evaluate the effectiveness of various natural and engineered media and various plant species on pollutant removal subjected to a range of pollutant loadings …

Concrete Maturity Method Applied To Rapid-Setting Calcium-Sulfoaluminate (Csa) Concretes For Pavement Repair Under Different Ambient Temperatures, Ryan Nicholas Langford

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

With more and more people using roadways the need for fast and efficient repair work is becoming increasingly important. Lane closures impede traffic flow and result in congestion. To further limit the amount of time lane closures are needed for repair work, calcium sulfoaluminate (CSA) cement concrete has become an increasing popular construction material for its ability to reach adequate strength requirements within four hours. Because of this accelerated repair time, advanced testing methods are needed to verify that the replaced concrete does indeed meet or exceed the minimum compressive strength requirements.

The maturity method is one test used to …

Surrogate Optimization Model For An Integrated Regenerative Methanol Transcritical Cycle, Yili Zhang

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In order to reduce the cost ($) per megawatts hour (MWh) of electrical energy generated by a nuclear power cycle with a novel small modular reactor (SMR), a new SMR-based nuclear power cycle with Methanol as working fluid was designed. It was built virtually with the Python & Coolprop software based on all components’ physical properties, and it is therefore called the physics-based model. The physics-based model would require seven user-defined values as input for the seven free design parameters, respectively. The physics-based model outcomes include LCOE (the cost per megawatts hour of electrical energy generated by the …

Vortex-Oriented Ferroelectric Domains In Snte/Pbte Monolayer Lateral Heterostructures, Kai Chang, John W. D. Villanova, Jing-Rong Ji, Souvik Das, Felix Kuster, Salvador Barraza-Lopez, Paolo Sessi, Stuart S. P. Parkin

Physics Faculty Publications and Presentations

Heterostructures formed from interfaces between materials with complementary properties often display unconventional physics. Of especial interest are heterostructures formed with ferroelectric materials. These are mostly formed by combining thin layers in vertical stacks. Here the first in situ molecular beam epitaxial growth and scanning tunneling microscopy characterization of atomically sharp lateral heterostructures between a ferroelectric SnTe monolayer and a paraelectric PbTe monolayer are reported. The bias voltage dependence of the apparent heights of SnTe and PbTe monolayers, which are closely related to the type-II band alignment of the heterostructure, is investigated. Remarkably, it is discovered that the ferroelectric domains in …

Wavelength And Power Dependence On Multilevel Behavior Of Phase Change Materials, Gary A. Sevison, Joshua A. Burrow, Haiyun Guo, Andrew M. Sarangan, Joshua R. Hendrickson, Imad Agha

Electro-Optics and Photonics Faculty Publications

We experimentally probe the multilevel response of GeTe, Ge2Sb2Te5 (GST), and 4% tungsten-doped GST (W-GST) phase change materials (PCMs) using two wavelengths of light: 1550 nm, which is useful for telecom-applications, and near-infrared 780 nm, which is a standard wavelength for many experiments in atomic and molecular physics. We find that the materials behave differently with the excitation at the different wavelengths and identify useful applications for each material and wavelength. We discuss thickness variation in the thin films used as well and comment on the interaction of the interface between the material and the substrate with regard to the …

The Facility Infection Risk Estimator™: A Web Application Tool For Comparing Indoor Risk Mitigation Strategies By Estimating Airborne Transmission Risk, Marcel Harmon, Josephine Lau

Durham School of Architectural Engineering and Construction: Faculty Publications

The COVID-19 pandemic created needs for (a) estimating the existing airborne risk of infection from SARS-CoV-2 in existing facilities and new designs and (b) estimating and comparing the impacts of engineering and behavioural strategies for contextually reducing that risk. This paper presents the development of a web application to meet these needs, the Facility Infection Risk Estimator™, and its underlying Wells–Riley based model. The model specifically estimates (a) the removal efficiencies of various settling, ventilation, filtration and virus inactivation strategies and (b) the associated probability of infection, given the room physical parameters and number of individuals infected present with either …

Interior Point Optimization Of Low-Thrust Spacecraft Trajectories, Jordan D. Frederiksen

Master's Theses

Low-thrust interplanetary spacecraft trajectory optimization poses a uniquely difficult problem to solve because of the inherent nonlinearities of the dynamics and constraints as well as the large size of the search space of possible solutions. Tools currently exist that optimize low-thrust interplanetary trajectories, but these tools are rarely openly available to the public, and when they are available they require multiple interfaces between multiple different packages. The goal of this work is to present a new piece of low-thrust interplanetary spacecraft trajectory optimization software that is open-source and entirely self-contained so that more people can have access to the ability …

Subclinical Atherosclerosis Quantified Through Cumulative Shear Measurement, Margaret Lynne Papka

Master's Theses

With the high mortality rate of cardiovascular disease, it is important to study the early signs. The early detection of cardiovascular disease can lead to saved lives. Currently the most prevalent detection methods are the Framingham Risk Score and the carotid intima media thickness, both of which are insufficient. The necessary tool for early detection requires a uniform quantification system. The stimulus leading to endothelial dysfunction, the most significant predictor of a major adverse cardiovascular event (MACE)—and subsequently subclinical atherosclerosis—is reduced shear stress. Increased surface relative roughness affects the flow profile transition from laminar to turbulent resulting in reduced shear …

Snr: Software Library For Introductory Robotics, Spencer F. Shaw

Master's Theses

This thesis introduces "SNR," a Python library for programming robotic systems in the context of introductory robotics courses. Greater demand for roboticists has pressured educational institutions to expand robotics curricula. Students are now more likely to take robotics courses earlier and with less prior programming experience. Students may be attempting to simultaneously learn a systems programming language, a library API, and robotics concepts. SNR is written purely in Python to present familiar semantics, eliminating one of these learning curves. Industry standard robotics libraries such as ROS often require additional build tools and configuration languages. Students in introductory courses frequently lack …

Nonlinear Model Development And Validation For Ball And Plate Control System, Zachary Richter

Master's Theses

Ball and plate balancing control systems are commonly studied due to the complex dynamics associated with the instability of the system in open-loop. For simplicity, mathematical models describing the ball and plate dynamics are often linearized and the effects of complex motion are assumed to be negligible. These assumptions are rarely backed with evidence or explanations validating the simplified form of the dynamical equations of motion. This thesis focuses on developing a nonlinear model that more accurately defines the dynamics of the system, in order to quantify the error of linear and nonlinear models when compared to a Simscape physical …

Micro Scalable Graphene Oxide Productions Using Controlled Parameters In Bench Reactor, Carolina S. Andrade, Anna Paula Godoy, Marcos Antônio Gimenes Benega, Ricardo J. E. Andrade, Rafael Cardoso Andrade, Wellington Marcos Silva, Josué Marciano De Oliveira Cremonezzi, Waldemar Augusto De Almeida Macedo, Hélio Ribeiro, Jaime Taha-Tijerina

Manufacturing & Industrial Engineering Faculty Publications

The detailed study of graphene oxide (GO) synthesis by changing the graphite/oxidizing reagents mass ratios (mG/mROxi), provided GO nanosheets production with good yield, structural quality, and process savings. Three initial samples containing different amounts of graphite (3.0 g, 4.5 g, and 6.0 g) were produced using a bench reactor under strictly controlled conditions to guarantee the process reproducibility. The produced samples were analyzed by Raman spectroscopy, atomic force microscopy (AFM), x-ray diffraction (XDR), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR) and thermogravimetry (TGA) techniques. The results showed that the major GO product comprised of nanosheets containing between 1–5 layers, …

An Enhanced Framework To Compute Road User Costs Associated With Construction Zones, Jeremiah Adebiyi

Electronic Theses and Dissertations

The monetary quantification of inconveniences caused to the road users by ongoing construction activities is known as the Road Users Costs (RUCs). While the importance of RUCs is widely known, some highway agencies lack an appropriate methodology to compute RUCs. Thus, there is a need to develop a framework to compute RUCs that can be adopted quickly by highway agencies. This study reviewed existing literature and conducted a nationwide survey to identify and summarize the current practices of computing RUCs. It developed an enhanced framework and tool to compute RUCs that balances the effort required to calculate RUCs and the …

Quantification Of Compound And Cascading Hydroclimatic Extreme Events, Sourav Mukherjee

All Dissertations

Compound and cascading hydroclimatic extreme events have garnered much attention in recent studies. The combined effects of interconnected extremes can cause widespread damage, with a higher potential impact than individual extremes. Both anthropogenic warming and natural climate variability affect these extremes, which is why detecting past extreme events, understanding the underlying mechanisms, and assessing their future impacts can aid in mitigation efforts to reduce their overall impact. However, thus far, identifying such events is oversimplified and the propagation of their impact as cascades from the physical to human systems remains partly explored.

The overreaching goal of this thesis is to …