Engineering Commons^™

Hydrodynamic Forces On Stream-Crossing Bridges – Consideration Of Flow Parameters, Bridge Geometry, And Debris, Shah Md Imran Kabir

Civil Engineering Dissertations - Archive

ABSTRACT: This thesis examines the interaction of flood flow with bridge superstructures by considering the effects of the flow parameters, bridge geometry, debris, and bridge substructures. The hydrodynamic forces are expressed by using force and moment coefficient charts to portray the effect of bridge submersion, bridge position with respect to the channel bed, flood velocity, and bridge geometry. Of the 580,000 bridges in the United States, 83% span streams and rivers that may subject them to floods and debris loads. Although bridges are designed to withstand hydrodynamic forces, the most frequent causes of failure are attributed to hydraulic events, including …

Experimental Validation Of A Reflective Long Period Grating Design Methodology, Sohel Rana, Nirmala Kandadai, Harish Subbaraman

Electrical and Computer Engineering Faculty Publications and Presentations

In this work, we present an experimental demonstration of our previously published modeling work on reflective long period grating (LPG). To provide the practical realization of the modeling work, we coat a long segment of fiber both in the tail length and the end facet beyond the gratings with silver to invert the transmission mode LPG to reflection mode LPG. We then measure the LPG characteristics in both the transmission and reflection mode and validate our findings from modeling work. We further build temperature and refractive index (RI) sensors and demonstrate temperature sensing from 21 °C to 191 °C with …

Exploring The Deformation Mechanics Of Coal Ribs Using The Distinct Element Modeling Approach, Maurice Sunkpal, Taghi Sherizadeh

Mining Engineering Faculty Research & Creative Works

Understanding coal rib geomechanics is essential for improving rib stability and eliminating fatality and injury trends due to rib failures. There are presently no standardized rib control practices available in most countries. In light of this observed dearth, this investigation aims to improve understanding of rib failure mechanisms using the distinct element modeling (DEM) technique. DEM is chosen because of its superior advantage to explicitly represent discontinuities and their constitutive behaviors, besides that of the intact rock matrix. To analyze the rib stability, a numerical monitoring protocol is implemented to monitor the deformation characteristics of the coal rock mass as …

A Spatiotemporal Analysis Of Food Pantry Accessibility In Washington County, Arkansas, Coleman Warren

Industrial Engineering Undergraduate Honors Theses

Food pantries are an essential resource for impoverished and food insecure communities. Washington County, Arkansas has a food insecurity rate of 14.3% as compared to the national average of 10.9% (Feeding America, 2019). The Northwest Arkansas Food Bank has a robust pantry network in Washington County to support families and individuals who struggle with food insecurity.

We conducted a spatiotemporal analysis of food pantry accessibility in Washington County, Arkansas to evaluate the effectiveness of the food pantry network in Washington County at supporting communities with the most need. This analysis was conducted using the Two-Step Floating Catchment Area (2SFCA) method …

Assessing The Influence Of Health Policy And Population Mobility On Covid-19 Spread In Arkansas, Tayden Barretto

Industrial Engineering Undergraduate Honors Theses

The outbreak of COVID-19 has created a major crisis across the world since its start in 2019, and its influence on every realm of society is undeniable. Globally, more than 500 million cases have been recorded since March 2020, with almost 6 million deaths. In the wake of this crisis, many governments and health organizations have taken steps and precautions to mitigate its spread. These steps involve public mandates of information, reducing frequency of personal contact, and use of masks to minimize the risk of transmission. Current access to mobility data released from Google detailing population movements has provided a …

Analyzing Vulnerabilities In The Northwest Arkansas Highway Network Using Mathematical Optimization, Brandon Jerome

Industrial Engineering Undergraduate Honors Theses

The highway and bridge network is a critical infrastructure that allows for the free transportation of citizens and enables truck-borne freight transportation. Disruption of this system could be caused by a terrorist attack, natural disaster, growth of population, required repairs and upgrades, or collapse caused by old age or malfunction. In the event of a disruption cities and regions can experience increased traffic and supply chain shortages, thus causing cascading effects throughout surrounding areas. With this motivation, we develop a network interdiction optimization model to identify a limited subset of roads that, if disrupted, causes the greatest increase in the …

Insect Antennae As Bioinspirational Superstrong Fiber-Based Microfluidics, Griffin J. Donley

All Theses

Nature is frequently turned to for inspiration for the creation of new materials. Insect antennae are hollow, blood-filled fibers with complex shape, and are cantilevered at the head. The antenna is muscle-free, but the insect can controllably flex, twist, and maneuver it laterally. To explain this behavior, a comparative study of structural and tensile properties of the antennae of Periplaneta americana (American cockroach), Manduca sexta (Carolina hawkmoth), and Vanessa cardui (painted lady butterfly) was performed. These antennae demonstrate a range of distinguishable tensile properties, responding either as brittle fibers (Manduca sexta) or strain-adaptive fibers that stiffen when stretched (Vanessa cardui …

Near-Earth Ion Irradiation Effects On Functional Ceramic Materials: A Combined Experimental-Monte Carlo Approach, William J. Sands

All Theses

The near-Earth space radiation environment is a complex system that creates a harmful environment for materials to operate in. Motivated by the search for using optical defects as an indicator of radiation damage, five single-crystal functional ceramic materials were selected to undergo ion irradiation at conditions found in the near-Earth space environment. Due to the complex nature of ion irradiation effects in ceramic materials, a host of calculations and experimental characterization methods were used. Calculations using the 2013 SRIM code were used to evaluate the ion projected range and the type and number of defects (vacancies) created by ion irradiation. …

Investigations Of External Resources And The Impact Of Imaging On Patient Flow In The Emergency Department, Marisa Shehan

All Theses

The problems associated with Emergency Department (ED) crowding are numerous, varied, and complex. Though overcrowded Emergency Departments are frequently attributed to overcrowded hospitals, crowding is also impacted by bottlenecks in patient flow. While discrete-event simulation (DES) is commonly used to model ED flow, external resources are typically excluded from these models due to their complexity and the limited amount of known information for these processes. Instead, external resources such as consults, labs, and imaging are modeled using estimation and/or educated guesswork. In this study, the impact of imaging on patient flow was assessed through data analysis of specific imaging factors, …

A Study On Effect Of Manufacturing Parameters On Morphology Of A356 Aluminum Foam, Nikhil Nanabhau Mahajan

All Theses

Metal foams have shown an excellent promise for usage as multifunctional material concerning research & development in the last 20 years. They provide remarkable mechanical as well as physical properties being lightweight. Open-cell metal foams have already been used in sound and noise absorption. Open-cell metal foams are outstanding for use in heat exchangers, filters, and many more applications, while closed-cell foams show excellent characteristics in impact energy absorptions. Closed-cell metal foams have higher energy absorption than their solid parent metal as they convert most of the impact energy into deformation energy. Metal foams have been used as prominent safeguard …

Improving Intelligent Transportation Safety And Reliability Through Lowering Costs, Integrating Machine Learning, And Studying Model Sensitivity, Cavender Holt

All Theses

As intelligent transportation becomes increasingly prevalent in the domain of transportation, it is essential to understand the safety, reliability, and performance of these systems. We investigate two primary areas in the problem domain. The first area concerns increasing the feasibility and reducing the cost of deploying pedestrian detection systems to intersections in order to increase safety. By allowing pedestrian detection to be placed in intersections, the data can be better utilized to create systems to prevent accidents from occurring. By employing a dynamic compression scheme for pedestrian detection, we show the reduction of network bandwidth improved by 2.12× over the …

Autonomous Aerial Vehicles Distributed Control And Interactive Games, Yusuf Kartal

Mechanical and Aerospace Engineering Dissertations - Archive

As the number of quadrotors and other Unmanned Aerial Vehicles (UAVs) increases in industrial and urban areas, the development of reliable engineering methods to control their behavior as they interact with each other becomes of central interest in control research. With the increase in demand for UAVs to work together, several real-life challenges need to be addressed that include the implementation, test, and validation of the control algorithms in flight test experiments. On the one hand, the interests of UAVs may be in harmony to perform certain tasks such as transportation, surveillance and reconnaissance. On the other hand, the interests …

Asset Management Of Wastewater Interceptors Adjacent To Bodies Of Water, Mohammad Bani Fawwaz

Civil Engineering Dissertations - Archive

This dissertation presents the viability of managing a pipeline network adjacent to bodies of water to maximize asset life by evaluating the significant factors that affect the condition levels of pipeline assets. Pipeline asset management derives from pipelines’ physical conditions, condition rating, and serviceability through testing, monitoring, and analyzing rupture history. The remaining asset life and structural condition of the pipeline network running near and under bodies of water are often hard to predict. In case of pipeline failure, exuberant damages will occur to the surrounding environment, adding up to disruption in service and repairing costs. This research develops Multinomial …

Photonic Crystal Surface Emitting Lasers, Akhil Raj Kumar Kalapala

Electrical Engineering Dissertations - Archive

ABSTRACT: Since the initial proposal in 1999 by Noda et al., photonic crystal surface emitting lasers (PCSELs) have proven to achieve large area, coherent lasing with a narrow, single mode beam. Owing to their unique orthogonal electrical/optical cavity scheme, PCSELs have emerged as one of the most promising platforms for high power diode lasers. The evanescent coupling of the optical mode in the active region with the photonic crystal layer enables large area two dimensional in-plane lasing mode in the photonic crystal cavity due to bandedge effect. Bragg’s multi-order diffraction provides the necessary feedback for the lasing and enhances surface …

Evaluation And Modeling Of Power System Components, Zachary Ryan Bailey

Electrical Engineering Dissertations - Archive

Future power system architectures will rely on a combination of rotating machines, power electronic devices, and energy storage. While it is possible to procure each component separately and conduct studies incorporating these devices into a system, increases in computing power and advanced computer modeling software have expanded the opportunity for research to be conducted on power system architectures without the need for actual hardware. This provides flexibility by allowing the user to design models of individual components that can then be integrated together or effortlessly interchanged depending on the function or testbed design that is being studied. The UTA IDEAL …

Optimizing The Performance Of Analytical Chemistry Instrumentation, Srividya Sekar

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

Surrogate Optimization and Global Optimization approaches to optimize underlying functions have been studied and used extensively in the field of Operations Research. However, there are very few instances where these approaches have been applied and tested in applications with uncertainty. Additionally, extensive focus and effort have been put into developing highly complex metamodels rather than globally optimizing these metamodels. In this study, we propose a Mixed Integer Quadratically Constrained Program (MIQCP) based approach that globally optimizes a Quintic Multivariate Adaptive Regression Splines (QMARS) metamodel. The QMARS-MIQCP based optimization is applied to a global optimization framework called QMARS-MIQCP-OPT to optimize several …

Exploring Deep Learning In Finance, Abhijit Anand Anand Deshpande

Industrial, Manufacturing, and Systems Theses - Archive

Financial market analysis is process of analyzing market closely and predict the next move of market whether it will go up or down using historical data. Financial market is stochastic and has rapid changes over time, therefore it is very difficult to predict. The main goal of this work is to understand novel approaches of machine learning in finance, data parsing techniques, labelling the financial data. Furthermore, understand state of art Transformer model and implement and compare results with other traditional machine learning algorithms. Experiment carried out in python along with pytorch.

Enhancing Stability Of High-Nickel Cathodes For Lithium-Ion Batteries Through Additive Manufacturing Of Cathode Structure, Matthew Sullivan

Mechanical Engineering Undergraduate Honors Theses

Lithium-ion batteries (LIBs) are currently the best method to store electrical energy for use in portable electronics and electronic vehicles. New cathode materials for LIBs are consistently studied and researched, but few are as promising and attainable as nickel-rich transition metal oxides such as LiNi1-x-yMnxCoyO2 (NMC). NMC materials exist with many different mass ratios, but higher nickel content materials provide higher energy density. With this increase in capacity comes a sacrifice with cyclability, as high-nickel NMC variants are prone to structure collapse, transition metal dissolution, and cracks due to volume change. In this report, mechanical modification of the electrode by …

Speaker Diarization And Identification From Single-Channel Classroom Audio Recording Using Virtual Microphones, Antonio Gomez

Electrical and Computer Engineering ETDs

Speaker identification in noisy audio recordings, specifically those from collaborative learning environments, can be extremely challenging. There is a need to identify individual students talking in small groups from other students talking at the same time. To solve the problem, we assume the use of a single microphone per student group without any access to previous large datasets for training.

This dissertation proposes a method of speaker identification using cross-correlation patterns associated to an array of virtual microphones, centered around the physical microphone. The virtual microphones are simulated by using approximate speaker geometry observed from a video recording. The patterns …

Design & Analysis Of Mixed-Mode Integrated Circuit For Pulse-Shape Discrimination, Bryan Orabutt

McKelvey School of Engineering Graduate Student Theses & Dissertations

In nuclear science experiments it is usually necessary to determine the type of radiation, its energy and direction with considerable accuracy. The detection of neutrons and discriminating them from gamma rays is particularly difficult. A popular method of doing so is to measure characteristics intrinsic to the pulse shape of each radiation type in order to perform pulse-shape discrimination (PSD).

Historically, PSD capable systems have been designed with two approaches in mind: specialized analog circuitry, or digital signal processing (DSP). In this work we propose a PSD capable circuit topology using techniques from both the analog and DSP domains. We …

Interdiction Models To Disrupt The Operations Of Sex Trafficking And Other Forced Illicit Labor Networks, Michael T. Clark

All Theses

Sex traffickers often force their victims to work in both commercial sex markets and perform other illicit activities (e.g., drug dealing, theft, and fraud). Current literature has failed to address interdiction models that aim to disrupt all components of a sex traffickers’ operation, including these other illicit activities. In this thesis, we present a interdiction problem, and its single-level linear optimization reformulation, to reduce the profit of a human trafficking network concurrently operating in the commercial sex market and other illicit activity markets. Our novel formulation aims to investigate the practical implications of interdiction decisions made to disrupt a human …

Addressing The Performance Of Distance Relays In Presence Of Inverter Based Resources, Prabin Adhikari

All Theses

The transition towards clean energy initiatives to reduce global greenhouse emissions and the dependence on fossil fuels requires the interconnection of large-scale renewable energy power plants to high voltage transmission networks via inverters. These inverter interfaced power sources, popularly known as inverter-based resources (IBRs), pose several technical challenges to the existing distance protection infrastructures widely deployed in transmission systems.

Fault characteristics of IBRs are significantly different from those shown by synchronous generators (SGs). With IBRs taking a large share of generation, their increasing penetration at the transmission level causes incorrect operation of existing distance protection schemes designed for systems dominated …

A Multi-Perspective Architecture Framework For Managing Multi-Fidelity Simulations Using Feature-Based Product Line Engineering, Ryan Colletti

All Dissertations

This dissertation aims to facilitate the process for generating system-level simulations using new and existing product line engineering practices within a SysML reference architecture of the simulation domain. The modern passenger vehicle is becoming increasingly complex with the addition of more software-oriented features, especially Advanced Driver Assistance Systems (ADAS), leading to higher numbers of recalls. To mitigate this, the result of this research is the novel Vehicle Simulation Architecture Framework (VSAF). This dissertation presents the VSAF, its innovations, and a characterization of its scalability, applicability, and initial investment vs. incremental cost tradeoffs as compared to those of current simulation practices. …

Modeling Energy Efficiency Of Solar Thermal Powered Batch Reverse Osmosis, Lahiri Chitturi

Discovery Undergraduate Interdisciplinary Research Internship

Batch reverse osmosis is the most energy efficient water desalination method and when powered by renewable energy, suggests promise for a cost-effective, low-carbon solution. One abundant energy source on Earth is solar energy which can be implemented using solar panels which have an established maximum efficiency of 25%, or solar thermal engines which can outperform solar photovoltaic systems by achieving higher efficiencies between 20% and 40% according to market research. Here, an approach to model and quantify the energy efficiency of a direct-drive solar thermal powered batch reverse osmosis system is presented to indicate the feasibility of pursuing this technology. …

Managing Humidity In Electronics Using Water Vapor-Selective Membranes, Songhao Wu, Andrew J. Fix, Allison Mou, David M. Warsinger, James Braun

Discovery Undergraduate Interdisciplinary Research Internship

Abstract: As outdoor electronics have become prevalent in every aspect of daily life, handling humidity in them is an emerging issue for reliable devices. As water vapor enters the electronics enclosure, there is a risk of condensation, which could prevent the electronics from functioning and further damage the device. Traditionally, the humidity removal for electronics is usually done by heating the air within the enclosure, which can be energy-intensive and less efficient. Vapor selective membrane systems are promising alternatives for air heating dehumidification as they do not require heating energy for water vapor removal. It allows water vapor transport through …

Evaluating And Addressing The Transportation Challenges Of Small-Scale Farmers And Ranchers In Regional Food Systems, Narjes Sadeghiamirshahidi

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

During the last 20 years, there has been a significant increase in US consumers’ interest in local food. At the same time, there is substantial potential demand for crops produced by local small and mid-size farmers and ranchers whose market channels are short distance distributions Although there is a variety of definitions for local food, it often refers to direct-to-customer market channels for farmers and ranchers, including farmers’ markets and Community Supported Agriculture (CSA), as well as distribution through local businesses like restaurants, grocery stores, as well as local institutions such as hospitals and schools. However, small and mid-size farmers …

Leveraging Ai And Supply Chain Technologies With Thermal Imaging And Telemedicine For Early Detection And Prevention Of Covid-19 And Respiratory Infections In Urm Communities, Gohar Azeem

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

The underserved population could be at risk during the times of crisis, unless there is strong involvement from government agencies such as local and state Health departments and federal Center for Disease Control (CDC). The COVID-19 pandemic was a crisis of different proportion, creating a different type of burden on government agencies. Vulnerable communities including the elderly populations and communities of color have been especially hard hit by this pandemic. This forced these agencies to change their strategies and supply chains to support all populations receiving therapeutics. The National Science Foundation (NSF Award # 2028612) funded this research to help …

Microfluidic Flow Focusing Platforms For Optofluidic Droplet Laser Development, Chen Zhang

Electrical Engineering Dissertations - Archive

ABSTRACT: Optofluidic droplet lasers have been developed for different applications in biomedical sciences, such as biosensing, cell tracking, tissue imaging, on-chip spectroscopy, and flow cytometry. Utilizing different generation methods, droplet lasers can be categorized as either static droplet lasers or droplet lasers on the flow. Static droplet lasers, which are supported by a surface or levitated by an external force, can be optically probed for an extended period of time, and thus enabling continuous monitoring of the lasing emission. However, static droplet lasers suffer from low-throughput generation, large size distribution, and poor reproducibility. In contrast, droplet lasers on the flow …

Power Allocation And Massive Mimo Channel Modeling For 5g Wireless Communications, Zhangliang Chen

Electrical Engineering Dissertations - Archive

To meet the demand for wireless communication transmission rate to reach a thousand times of the existing system in 2021, the fifth-generation (5G) mobile communication system was developed. Compared with Long-Term Evolution (LTE), the 5G mobile communication needs to be transmitted in wireless breakthrough innovation in technology to achieve the goal of ten times increase in spectrum efficiency and power efficiency. As a time series analysis tool based on vector autoregression, Granger causal analysis originated in the field of econometrics, and its staged generalized transfer entropy (TE) based on conditional co-information in information theory has been widely used in recent …

Surface Flashover Under Various Surface Conditions, Bradley A. Hannum

Electrical Engineering Theses - Archive

Electrical insulators are critical components used in every high voltage application whether it is operated continuously or in a pulsed mode. Bulk dielectric breakdown and surface flashover must be prevented in all use cases, especially those that occur in polluted environments. Though electrical standards have been written as a guide to prevent insulator surface flashover, such as Underwriters Laboratories (UL) 840, they are not directly applicable to applications where size and weight are critical. UL 840 experimental design is vague, does not consider all environments, and is written primarily with the electric power utilities in mind. The research presented here …