Engineering Commons^™

Evaluating Measurement Of Strain Hardening Method For Mechanical Assessment Of Geomembrane Service Life In Msw Landfills, Alaa Alsharaballi

Theses and Dissertations

The increased household production result in more construction of municipal solid waste (MSW) landfills and lagoons. One major part of these engineering projects is high-density polyethylene (HDPE) geomembrane. Geomembrane is an impermeable layer that used along bottom and sides of landfills and lagoons to contain the leachate and to protect the groundwater. Although of their chemicals resistance and high strength, it can be aged under service conditions such as high temperature, ultraviolet (UV) light, and chemicals exposure. These conditions accelerate oxidation of geomembrane and lead to brittle behavior and stress cracking which reduce its service life.

Our objective in this …

Modeling Neutron Interaction Inside A 2d Reactor Using Monte Carlo Method, A. S. M. Fakhrul Islam

Theses and Dissertations

Scientists and engineers have been working for many years to develop accurate approaches to analyzing nuclear power reactors using computer codes that closely model the behavior of neutrons in a reactor core. The Monte Carlo simulation method is capable of treating complex geometries with a high level of resolution and fidelity to model neutron interactions inside a reactor core. With the requirement of accurate modeling in reactor physics and dynamics and great innovation of computer technology, Monte Carlo method is becoming an ever more powerful tool and receiving rising attention. In this study, Monte Carlo method is used to model …

Person Identification With Convolutional Neural Networks, Kang Zheng

Theses and Dissertations

Person identification aims at matching persons across images or videos captured by different cameras, without requiring the presence of persons’ faces. It is an important problem in computer vision community and has many important real-world applica- tions, such as person search, security surveillance, and no-checkout stores. However, this problem is very challenging due to various factors, such as illumination varia- tion, view changes, human pose deformation, and occlusion. Traditional approaches generally focus on hand-crafting features and/or learning distance metrics for match- ing to tackle these challenges. With Convolutional Neural Networks (CNNs), feature extraction and metric learning can be combined in …

A Novel And Inexpensive Solution To Build Autonomous Surface Vehicles Capable Of Negotiating Highly Disturbed Environments, Jason Moulton

Theses and Dissertations

This dissertation has four main contributions. The first contribution is the design and build of a fleet of long-range, medium-duration deployable autonomous surface vehicles (ASV). The second is the development, implementation, and testing of inex-pensive sensors to accurately measure wind, current, and depth environmental vari- ables. The third leverages the first two contributions, and is modeling the effects of environmental variables on an ASV, finally leading to the development of a dynamic controller enabling deployment in more uncertain conditions.

The motivation for designing and building a new ASV comes from the lack of availability of a flexible and modular platform …

Bison Simulation-Based Identification Of Important Design Criteria For U3si2 Fuels With Composite-Monolithic Duplex Sic Cladding, Jacob A. Yingling

Theses and Dissertations

Accident Tolerant Fuels (ATF) require a combination of fuel and cladding which have comparable longevity characteristics to UO2 while improving resistance to radiological release during and after accidents. U3Si2 has been proposed for use in ATF concepts for its high uranium density and high thermal conductivity which provide improved fuel performance. However, some of U3Si2’s material properties are not well understood. One such property, thermal creep of U3Si2, is an important contributing factor to U3Si2’s viability as an ATF. No experimentally derived thermal creep model is published for U3Si2, and previous analyses of compressive thermal creep experimental data lack statistical …

Experimental Investigation Of Hydraulic Effects On Unsaturated Soils Behaviors, Muwafaq Awad

Theses and Dissertations

Geo-structures are frequently constructed in or on soils with unsaturated conditions and are subjected to variations of moisture contents due to seasonal changes. Even though unsaturated soil mechanics have been established for several decades, it has not been fully implemented in practice today because of a lack of understanding of the interaction between the soil, water, and air phases. Many experimental research studies have been conducted to improve the understanding of unsaturated behavior but these studies are typically limited to small soil elements tested under fully drained conditions. The goal of this research is to evaluate the effect of hydraulics …

Adipose Tissue Engineering: A Therapeutic Strategy For The Treatment Of Obesity And Glucose Intolerance, Michael A. Hendley

Theses and Dissertations

Despite available treatment options, the number of people afflicted by type 2 diabetes has steadily risen for decades. Nearly 90% of the diabetic population also suffers from obesity and the link between the two diseases is undeniable. Characterized by rapid expansion of the adipose tissue and improper lipid storage, the mishandling of lipids by adipose tissue promotes the diabetic state. Excess lipids, unable to be properly stored, build up in peripheral tissues promoting insulin resistance and type 2 diabetes. Therapeutic strategies designed to address adipose tissue lipid handling could represent a promising treatment strategy for obesity associated type 2 diabetes. …

Study Of Wire Arc Additive Manufacturing With Aluminum Alloy 2219, Sritam Kumar Dash

Theses and Dissertations

This thesis discusses WAAM (wire arc additive manufacturing) technology using TIG (Tungsten Inert Gas) welding method with aluminum 2219 as the substrate and aluminum 2319 as the filler material. The most important characteristic of this method of manufacturing is very little wastage of material as it does not follow the conventional method of manufacturing where material is removed from a bigger block to finally achieve the desired shape. This method uses a layer by layer approach to build the part. Generally, in additive manufacturing, the production time may vary depending on the type of method used. The material deposition rate …

Cybersecurity Issues In The Context Of Cryptographic Shuffling Algorithms And Concept Drift: Challenges And Solutions, Hatim Alsuwat

Theses and Dissertations

In this dissertation, we investigate and address two kinds of data integrity threats. We first study the limitations of secure cryptographic shuffling algorithms regarding preservation of data dependencies. We then study the limitations of machine learning models regarding concept drift detection. We propose solutions to address these threats.

Shuffling Algorithms have been used to protect the confidentiality of sensitive data. However, these algorithms may not preserve data dependencies, such as functional de- pendencies and data-driven associations. We present two solutions for addressing these shortcomings: (1) Functional dependencies preserving shuffle, and (2) Data-driven asso- ciations preserving shuffle. For preserving functional dependencies, …

Quantifying And Elucidating The Effect Of Co2 On The Thermodynamics, Kinetics And Charge Transport Of Aemfcs, Yiwei Zheng

Theses and Dissertations

Anion exchange membrane fuel cells (AEMFCs) have shown significant promise to provide clean, sustainable energy for grid and transportation applications – and at a lower theoretical cost than more established proton exchange membrane fuel cells (PEMFCs). Adding to the excitement around AEMFCs is the extremely high peak power that can now be obtained (> 3 W cm-2) and continuously improving durability (1000+ h), which has made the future deployment of AEMFCs in real-world applications a serious consideration. For some applications (e.g. automotive), the most critical remaining practical issue with AEMFCs is understanding and mitigating the effects of atmospheric CO2 (in …

Enhanced Heat Transfer In Spray Cooling Through Surface Modifications: An Experimental And Computational Study, Azzam Saadi Salman

Theses and Dissertations

Today, dissipating high heat flux safely is one of the greatest challenges for thermal engineers in thermal management systems, and it becomes a critical barrier to technological developments for many engineering applications. Due to technological advances and aggressive micro-miniaturization of electronic components, the surface area of most devices has shrunk while the computational power increased exponentially. Therefore, the amount of heat dissipated from surfaces has increased significantly. Numerous cooling techniques have been introduced to replace the traditional air cooling systems and to maintain the efficiency and reliability of electronic components. Microelectronics work efficiently and safely at surface temperatures of < 100 ℃ and 125 ℃ for general and defense applications, respectively. One of the proposed alternative schemes is spray cooling, which is considered one of the most advanced cooling methods. It is used for high and ultra-high heat flux dissipation, as it can dissipate 150-200 W/cm2 while maintaining the surface temperature within this range. Also, spray cooling removes a large amount of energy at a lower liquid flow rate compared to other cooling techniques, such as jet impingement and microchannel heat sink. The thermal performance of spray cooling systems can be enhanced either actively or passively. Active enhancement is a very efficient technique; however, it adds more pumping power. The present work focuses on three main objectives: evaluating and analyzing spray cooling performance, developing a three-dimensional numerical multi-phase model for heat transfer process in spray cooling and enhancing the thermal performance of spray cooling passively.

First, …

Properties, Learning Algorithms, And Applications Of Chain Graphs And Bayesian Hypergraphs, Mohammad Ali Javidian

Theses and Dissertations

Probabilistic graphical models (PGMs) use graphs, either undirected, directed, or mixed, to represent possible dependencies among the variables of a multivariate probability distri- bution. PGMs, such as Bayesian networks and Markov networks, are now widely accepted as a powerful and mature framework for reasoning and decision making under uncertainty in knowledge-based systems. With the increase of their popularity, the range of graphical models being investigated and used has also expanded. Several types of graphs with dif- ferent conditional independence interpretations - also known as Markov properties - have been proposed and used in graphical models.

The graphical structure of a …

Tissue-Specific Roles Of Transforming Growth Factor Beta Ligands In Cardiac Outflow Tract Malformations And Calcific Aortic Valve Disease, Nadia Al-Sammarraie

Theses and Dissertations

Congenital heart defects and adult calcific aortic valve disease are two of the leading causes of morbidity and mortality worldwide. To date, there is no medical cure and surgical intervention is the main option of treatment. The cardiac outflow tract is the major site for these abnormalities, which are triggered by genetic and/or environmental factors that alter development and/or homeostasis. Recently, significant roles of TGFβ signaling in development of cardiovascular disorders have become more evident in humans, however, the specific requirement of individual TGFβ ligands on the pathogenesis of OFT malformations and diseases remains elusive. In the present work, three …

Computational Wave Field Modeling In Anisotropic Media, Sajan Shrestha

Theses and Dissertations

In this thesis, a meshless semi-analytical computational method is presented to compute the ultrasonic wave field in generalized anisotropic material while understanding the physics of wave propagation in detail. To understand the wave-damage interaction in an anisotropic material, it is neither feasible nor cost-effective to perform multiple experiments in the laboratory. Hence, recently the computational nondestructive evaluation (CNDE) received much attention to performing the NDE experiments in a virtual environment. In this thesis, a fundamental framework is constructed to perform the CNDE experiment of a thick composite specimen in a Pulse-Echo (PE) and through-transmission mode. To achieve the target, the …

Stacked Modelling Framework, Kareem Abdelfatah

Theses and Dissertations

The thesis develops a predictive modeling framework based on stacked Gaussian processes and applies it to two main applications in environmental and chemical en- gineering. First, a network of independently trained Gaussian processes (StackedGP) is introduced to obtain analytical predictions of quantities of interest (model out- puts) with quantified uncertainties. StackedGP framework supports component- based modeling in different fields such as environmental and chemical science, en- hances predictions of quantities of interest through a cascade of intermediate predic- tions usually addressed by cokriging, and propagates uncertainties through emulated dynamical systems driven by uncertain forcing variables. By using analytical first and …

A Non-Contacting System For Rail Neutral Temperature And Stress Measurements, Katelyn Knopf

Theses and Dissertations

Continuous Welded Rail (CWR) has become the standard in modern railway track construction around the world because it alleviates well-documented disadvantages of rail joints in a track. CWR practice results in long segments of continuous rail in the track that will develop significant thermal elongation. To avoid the use of impractical large thermal expansion joints and limit the expected thermal elongation, the rail is anchored to the ties. Consequently, the rail is exposed to higher thermal stress demands as the rail temperature varies. At the time a CWR is laid, the rail is free of thermal stresses; the temperature at …

Discovery Of Materials Through Applied Machine Learning, Travis Williams

Theses and Dissertations

Advances in artificial intelligence technology, specifically machine learning, have cre- ated opportunities in the material sciences to accelerate material discovery and gain fundamental understanding of the interaction between certain the constituent ele- ments of a material and the properties expressed by that material. Application of machine learning to experimental materials discovery is slow due to the monetary and temporal cost of experimental data, but parallel techniques such as continuous com- positional gradients or high-throughput characterization setups are capable of gener- ating larger amounts of data than the typical experimental process, and therefore are suitable for combination with machine learning. A …

Molecular Modeling Of Tethered Polyelectrolytes For Novel Biomedical Applications, Merina Jahan

Theses and Dissertations

Current research trends throughout the world focus on designing intelligent materi- als and systems for diverse applications in all courses of life. Biomaterials research encompasses a major part in this revolution due to the increased effort in fulfilling unmet medical needs to treat complex physiological and neurodegenerative disorders. Polymers play inevitable roles in these research endeavors for their ubiquitous pres- ence in biological systems. Therefore, it is crucial to understand how the polymeric molecules interact within diverse biological environments, to efficiently engineer them for various drug delivery and biosensing systems. The use of experimental design and selection of different polymers …

Using A Nondispersive Wave Propagation For Measuring Dynamic Fracture Initiation Toughness Of Materials: Experimental And Numerical Based Study, Ali Fahad Fahem

Theses and Dissertations

Fracture mechanics has been a subject of great interest in the engineering community for decades. During this period, fracture parameters such as Stress Intensity Factor (SIF), J-integral, and Crack-Tip Opening Displacement (CTOD) have been developed and used to characterize the fracture properties of most engineering materials under quasi-static loading condition. Usually, these properties are obtained experimentally by using standard methods such as ASTM E399, E1820 or E1920 to evaluate the stress intensity factor ������ ������������, elastic-plastic toughness ������ ������������ and crack tip opening displacement (CTOD) respectively. Conversely, most critical engineering applications are subjected to a sudden or high strain rate …

Challenges In Large-Scale Machine Learning Systems: Security And Correctness, Emad Alsuwat

Theses and Dissertations

In this research, we address the impact of data integrity on machine learning algorithms. We study how an adversary could corrupt Bayesian network structure learning algorithms by inserting contaminated data items. We investigate the resilience of two commonly used Bayesian network structure learning algorithms, namely the PC and LCD algorithms, against data poisoning attacks that aim to corrupt the learned Bayesian network model.

Data poisoning attacks are one of the most important emerging security threats against machine learning systems. These attacks aim to corrupt machine learning models by con- taminating datasets in the training phase. The lack of resilience of …

Wireless Rf Induced Energy Absorption And Heating Of Lanthanum-Nickel Alloy In The Near-Field, Michael Dillon Lindsay

Theses and Dissertations

This thesis will investigate whether and how a synthetic metal-magnetic alloy absorbs enough near-field electromagnetic (EM) radiation for heating. Although resistive elements could be used for indirect heating, a wireless radio frequency (RF) method is explored because of its advantages in its non-intrusive nature and its ability to direct or focus energy within a specific area. For our case, the RF heating process relies on the materials ability to absorb sufficient RF energy due to the induced currents. We expect there to be significant surface resistance due to the conductivity and magnetic permeability of the material and thus heat. This …

Experimental Investigations Of Levee Breach Flows, Ibrahim Adil Ibrahim

Theses and Dissertations

Two individual but related problems involving levee breach flow are studied. The first one involves experimental and dynamic modeling of steady flow through a levee breach, and the second one involves experimental investigation of flood management by an engineered levee breach. Both studies are conducted in the Hydraulics Laboratory, the University of South Carolina.

In the first problem, an idealized levee breach on a trapezoidal embankment was studied. Flow data including water depths, surface velocities, and flow discharges were collected from 28 experiments considering different cases of breach width and downstream water depth. Ultrasonic sensors were used to record the …

Development Of A National-Scale Big Data Analytics Pipeline To Study The Potential Impacts Of Flooding On Critical Infrastructures And Communities, Nattapon Donratanapat

Theses and Dissertations

With the rapid development of the Internet of Things (IoT) and Big data infrastructure, crowdsourcing techniques have emerged to facilitate data processing and problem solving particularly for flood emergences purposes. A Flood Analytics Information System (FAIS) has been developed as a Python Web application to gather Big data from multiple servers and analyze flooding impacts during historical and real-time events. The application is smartly designed to integrate crowd intelligence, machine learning (ML), and natural language processing of tweets to provide flood warning with the aim to improve situational awareness for flood risk management and decision making. FAIS allows the user …

Characterization And Drying Of Oxyhydroxides On Aluminum Clad Spent Nuclear Fuel, Matthew Shalloo

Theses and Dissertations

Research reactors such as the Advanced Test Reactor (ATR) and the High Flux Isotope Reactor (HFIR) employ aluminum-clad fuel elements made up of many thin plates with uranium dispersed within. In most engineering applications, aluminum is considered to have favorable corrosion characteristics. It forms a thin oxide layer [Al2O3] under atmospheric conditions that is impenetrable to oxygen thus stopping any further corrosion. However, both aluminum metal and Al2O3 react with water to form hydrous oxides which are less protective against further corrosion and form significantly thicker layers than oxidation in dry air. As a result, aluminum-clad spent nuclear fuel (ASNF) …

Modeling The Uranium-Silicon Phase Equilibria Based On Computational And Experimental Analysis, Tashiema Lixona Ulrich

Theses and Dissertations

As part of Accident tolerant fuel initiative, the uranium-silicide compound, U3Si2, is under consideration as a potential replacement for conventional uranium dioxide fuel. It is of interest as its higher uranium density of 11.3 g(U)/cm3 compared to 9.7 g(U)/cm3 for UO2 may allow use of more robust, but less neutronically economical fuel cladding. The improved uranium content would not only accommodate the neutronic penalty inherent to certain accident tolerant cladding concepts but also facilitate improved reactor performance with the potential for longer fuel cycles.

The U-Si system has been the subject of various studies that mainly focused on thermophysical properties, …

Quantification Of Material Degradation For Material State Awareness Of Composite Materials., Vahid Tavaf

Theses and Dissertations

The objectives of this research are to develop a comprehensive method to quantify the material degradation of composite materials in the presence of distributed damages and predict the failure in the defected composites using the updated effective material properties. Defects can grow in composites at the macro scale caused by the microscale voids, matrix cracks, fiber breakages starting from manufacturing processes to the high and low cycle fatigue loads, high temperature, and high humidity during operation. Hence, to predict a more realistic failure model, it is necessary to consider the repercussions of degraded materials. The proposed research work is divided …

Surrogate Formulation Based On Chemical Functional Group Analysis, Stuart Nates

Theses and Dissertations

Chemical kinetic characteristics of real fuels exhibit high-dimensional complexity due to the excessive number of molecules and molecular classes. As a method of projecting this high-dimensional complexity, which is pertinent to real fuels, to the low-dimensional description, either a surrogate approach or detailed experiments have been utilized, can guide the construction of chemical kinetic models for real fuel. Although the validity of the surrogate approach has been extensively demonstrated by a wide range of canonical experiments for whole fuel/air mixtures, the use of empirical fuel property indicators still worries whether or not the surrogate mixture truly captures the more complex …

Fractional Order And Virtual Variable Sampling Design Of Repetitive Control For Power Converters, Zhichao Liu

Theses and Dissertations

With the growth of electricity demand and renewable energy power source, power converter becomes a more and more significant component in electrical power systems. The requirement of the power converter controller is to produce an accurate and low-distorted voltage or current under different load conditions. Although the conventional controller can meet the requirement of some applications, it requires accurate knowledge of the system model and cannot provide a satisfactory result especially under nonlinear loads or sudden load change. Repetitive control (RC) presents an attractive solution to achieve excellent steady-state tracking error and low total harmonic distortion for periodic signals, and …

Curbside Antenna To Vehicle Path Loss Measurements And Modeling In Three Frequency Bands, Patrick Murphy

Theses and Dissertations

V2V and V2I systems have been an increasingly important topic of study in recent years. Future V2I systems could involve antennas near or on the curb at intersections or on the ground along highways. To this end the curbside antenna to vehicle channel has not been studied very much. The scope of this thesis is to develop initial models for the path loss for examples of this channel. This was done through a measurement campaign where the transmitting antenna is located on the ground near the road and the receiver is in a vehicle driving towards the transmitter. The vehicle …

Enabling High Energy Density Aluminum Anodes For Alkaline Batteries, Xinyi Zhao

Theses and Dissertations

Zn-MnO₂ primary alkaline batteries stood out immediately among all batteries after it was introduced in the late 1980s and has attracted world-wide attention. These batteries have dominated the portable power market for decades as a highly effective energy storage system with high energy density, long life and low self-discharge, dependable safety and other superiorities.

In order to achieve higher cell-level energy density, Aluminum has long been considered a very attractive anode material for alkaline batteries because of its high theoretical capacity (2980 mAh/g; 2.60 Ah/cm³) and low price. However, some early efforts to utilize aluminum anodes did …