Engineering Commons^™

Human-Infrastructure Interfaces (Hii) Enabled Using Augmented Reality (Ar), Dilendra Maharjan

Civil Engineering ETDs

The modern industrial society is built upon the productivity of advanced computing and agile machines assisting the human workforce to perform their tasks more effectively, accurately and efficiently. The industrial revolution termed as "Industry 4.0" is based on the intelligence of machines working with humans in a collaborative work-space. Contrarily, infrastructure management has relied on the human for making day to day decisions. New emerging technologies can assist during infrastructure inspections, to quantify structural condition with more objective data. However, today's’ owners agree in trusting the inspector's decision in the field over data collected with sensors. If data collected in …

Coulombic And Non-Coulombic Effects Of Single And Overlapping Electric Double Layers With Surface Charge Regulation, Raviteja Vangara

Chemical and Biological Engineering ETDs

The physical origin of charged interfaces involving electrolyte solutions is in the thermodynamic equilibrium between the surface reactive groups and certain dissolved ionic species in the bulk. This equilibrium is very strongly dependent on the precise local density of these species, also known as potential determining ions in the solution. The latter, however, is determined by the overall solution structure, which is dominated by the large number of solvent molecules relative to all solutes. Hence, the solvent contribution to the molecular structure is a crucial factor that determines the properties of electric double layers. Models that explicitly account for the …

Retrofit Of Corroded Corrugated Metal Culverts Using Gfrp Slip-Liner, Rahulreddy Chennareddy

Civil Engineering ETDs

Culverts are water conveyance structures, typically used to allow water flow and maintain a balance between the flow streams without interrupting structures such as highways and bridges. Corrugated metal pipes (CMPs) have been used as culverts in North America since the 1950s because of their low cost and simple construction method. Today, the corrosion of CMPs is a major problem faced by all U.S. Departments of Transportation. There is an urgent need to provide an efficient solution, one that is corrosion-resistant, to retrofit thousands of corroded CMPs across the country. High specific strength, high strength to weight ratio, corrosion resistance, …

Non-Trivial Off-Path Network Measurements Without Shared Side-Channel Resource Exhaustion, Geoffrey I. Alexander

Computer Science ETDs

Most traditional network measurement scans and attacks are carried out through the use of direct, on-path network packet transmission. This requires that a machine be on-path (i.e, involved in the packet transmission process) and as a result have direct access to the data packets being transmitted. This limits network scans and attacks to situations where access can be gained to an on-path machine. If, for example, a researcher wanted to measure the round trip time between two machines they did not have access to, traditional scans would be of little help as they require access to an on-path machine to …

An Investigation Of The Chemistry, Thermodynamics And Catalytic Activity Of Molybdenum Carbides, Shanti Kiran Nayak

Chemical and Biological Engineering ETDs

These studies investigate the chemistry and stability of molybdenum carbides as an electrocatalyst. Due to their unique electronic properties, molybdenum carbides are purposed as electrocatalysts for reaction systems such as hydrogen evolution reaction, bifunctional water splitting and CO oxidation.

In this study, various synthesis processes were utilized to produce different types of molybdenum carbide with varying properties of particle size, surface area and excess carbon. The samples characterized by XRD accompanied by Whole Profile Fitting, Electron Microscopy, Gas Adsorption (surface area) and XPS.

These synthesis processes were refined using fundamental thermodynamic analyses. These analyses highlight regions of stability of different …

Robot Motion Planning In Dynamic Environments, Hao-Tien Lewis Chiang

Computer Science ETDs

Robot motion planning in dynamic environments is critical for many robotic applications, such as self-driving cars, UAVs and service robots operating in changing environments. However, motion planning in dynamic environments is very challenging as this problem has been shown to be NP-Hard and in PSPACE, even in the simplest case. As a result, the lack of safe, efficient planning solutions for real-world robots is one of the biggest obstacles for ubiquitous adoption of robots in everyday life. Specifically, there are four main challenges facing motion planning in dynamic environments: obstacle motion uncertainty, obstacle interaction, complex robot dynamics and noise, and …

Effects Of Temperature And Nitrogen Depletion On Biodiesel Production Under Saline Conditions By A Mixed Algal Community, Sarah J. Kintner

Nanoscience and Microsystems ETDs

The overall objective addressed in this research was to gain a better understanding of how native mixed cultures of phototrophic microorganisms from a saline system may be used for biodiesel production. Laboratory batch reactors were grown under variable temperatures and nitrogen concentrations with original inoculum from a hypersaline pond in central New Mexico. Growth at 40 C° led to lower lipid production, lower nitrate consumption, and less diverse communities than growth at 20° C. All communities were dominated by the cyanobacteria Plectonema except the in second experiment, where they were only 30% of the culture. In a second experiment with …

Additively Manufactured Continuous Carbon Fiber Thermoplastic Composites For High-Performance Applications, Nekoda Van De Werken

Mechanical Engineering ETDs

The goal of this dissertation is to provide a foundation for the advancement of additive manufacturing (AM) toward production of high-performance carbon fiber reinforced polymer matrix composites (CFRPs). AM can provide valuable advantages over conventional composite manufacturing techniques, including the control over fiber orientation, capability of manufacturing complex geometries, out-of-autoclave processing, elimination of the need for composite tooling, and the ability to perform lights-out manufacturing. Currently, however, a suite of challenges related to modelling, design, manufacturing defects, and general limitations in the current understanding of the processing-structure-property relationships exist in AM of composites. To this end, this dissertation investigates novel …

Optical Angular Scatterometry: In-Line Approach For Roll-2-Roll And Nano-Imprint Fabrication Systems, Juan Jose Faria-Briceno

Electrical and Computer Engineering ETDs

As critical dimensions continue to shrink and structures become more complex, metrology processes are challenging to implement during in-line nanomanufacturing. Non-destructive, non-contact, and high-speed conditions are required to achieve proper metrology processes during in-line manufacturing. Optical scatterometry is a nanoscale metrology tool widely used in integrated circuit manufacturing for characterization and quality control. However, most applications of optical scatterometry operate off-line. A high-speed, in-line, non-contact, non-destructive scatterometry angular system has been demonstrated in this work to scan pattern surfaces during real-time nano-fabrication.

Our system has demonstrated scanning capabilities using flat, 1D and 2D complex structures. The flat surface samples consist …

Source-Separated Urine Nitrification And Ion Accumulation In Sub-Irrigated Planters Using Domestic Wastewater, David A. Forrest

Civil Engineering ETDs

Wastewater reuse is a field at the crux of the food-energy-water nexus. This nexus is a modern attempt at qualifying relationships between resource availability and stewardship, and the choices and needs of market-driven culture. This study aims to develop simple low-tech systems to use domestic wastewater or source-separated urine, treated onsite, for domestic container garden water and nutrient supply. Four experiments were conducted to assess specific aspects of this technology to help develop relevant stages in this reuse chain.

The objective of the first experiment was a proof of concept to assess compatibility of sub-irrigated planters (SIP) with treated domestic …

Measurement Of Photoionization Rates In Air, Justin K. Smith

Electrical and Computer Engineering ETDs

The ionization of gas molecules from the absorption of photons produced in different parts of a discharge is an important process in the development of streamers. Photoionization rates are essential in the propagation of streamers and are therefore important in simulations of computational codes. Although streamers are widely used in computational codes, there is a limited data set on the experiments measuring photoionization rates in gases. Usually, the photoionization rate data used in computational codes comes from a single source and the validity of this data combined with the photoionization model has been questionable. It is postulated there is a …

Software Design For Probabilistic Safety: Stochastic Reachability And Circadian Control, Joseph D. Gleason

Electrical and Computer Engineering ETDs

Stochastic reachability is an important verification tool that provides probabilistic assurances of safety in a variety of contexts. In engineered systems, safety may be synonymous with the ability of the system to avoid "bad" constraints on the state space, that constitute collision, departure from a flight envelope, or other undesirable phenomenon. In biomedical systems, assurance of safety (such as the mandate to ``do no harm'') are considerably complicated by the fact that there is a lack of physics-driven models, extensive signal processing is needed to capture the underlying state of the system, and the stochasticity inherent to the system may …

Vision-Based Autonomous Tracking Of A Non-Cooperative Mobile Robot By A Low-Cost Quadrotor Vehicle, Cheikhna Ahmed Tidiane Sy

Electrical and Computer Engineering ETDs

The goal of this thesis is the detection and tracking of a ground vehicle, in particular a car-like robot, by a quadrotor. The first challenge to address in any pursuit or tracking scenario is the detection and unique identification of the target. From this first challenge, comes the need to precisely localize the target in a coordinate system that is common to the tracking and tracked vehicles. In most real-life scenarios, the tracked vehicle does not directly communicate information such as its position to the tracking one. From this fact, arises a non-cooperative constraint problem. The autonomous tracking aspect of …

Synthesis & Characterization Of Polymer-Modified Calcium Silicate Hydrate For Wellbore Applications, Jeremy J. Starr

Civil Engineering ETDs

Calcium Silicate Hydrate (C-S-H) acts as the primary binding material that is mainly responsible for the strength and durability of concrete. C-S-H constitutes approximately 67% of hydrated ordinary Portland cement by volume. C-S-H forms with a range of stoichiometric formula dependent on many factors such as CaO/SiO₂ ratio. The continued rise of hydrocarbon exploration in the United States has developed the need for improved wellbore cementing materials. Binders with good bond strength to steel and rock interfaces, low shrinkage, and high cracking strength are sought by the oil and gas industry. The incorporation polymers and nano materials has evolved …

Validation Of Gaseous Absorption & Cloud Attenuation Models Utilizing A 72 Ghz Terrestrial Link, Ralph Lyndon Gesner

Electrical and Computer Engineering ETDs

Interest in the W & V-bands of the radio frequency (RF) spectrum has become steadily more desirable for system designers due to the ever increasing need for greater communication bandwidths and higher data rates. The 40 GHZ to 110 GHz range that constitutes the W & V-bands provide a unique solution to both of these current demands by providing a bandwidth nearly double that of all current RF frequencies in use. To date, this range has only been used for point to point satellite and short link communications meaning these bands have remained largely unexplored and undeveloped.

To capitalize on …

Integrated Chirped-Grating Spectrometer-On-A-Chip, Shima Nezhadbadeh

Optical Science and Engineering ETDs

In this dissertation we demonstrate a new structure based on waveguide coupling atop a silicon wafer using a chirped grating to provide the dispersion that leads to a high-resolution, compact, fully integrable and CMOS-compatible spectrometer. Light is both analyzed and detected in a single, completely monolithic component which enables realizing a high-resolution portable spectrometer with an extremely compact footprint. The structure is comprised of a SiO₂/Si₃N₄/SiO₂ waveguide on top of a silicon wafer. Grating regions are fabricated on the top cladding of the waveguide. The input light is incident on a chirped grating …

Near-Field And Far-Field Microscopic And Spectroscopic Characterizations Of Coupled Plasmonic, Excitonic And Polymeric Materials, Chih-Feng Wang

Optical Science and Engineering ETDs

The properties of localized surface plasmons (LSP) have been broadly utilized for chemical sensing, surface enhanced Raman spectroscopy, biomedical imaging and photothermal treatments. By exploiting well-established plasmonic effects, the spectroscopic investigation of intriguing quantum phenomena, such as excitonic interband and intersubband (ISB) transitions in semiconductor heterostructures, was examined and extended in both far- and near-field optical measurements. For far-field characterization, we used colloidal plasmonic Au nanorods (AuNRs) to increase the quantum efficiency of InGaAs/GaAs single quantum well. By analyzing the temperature-dependent photoluminescence enhancement as a function of GaAs capping layer thickness, we attributed the mechanism of the LSP enhancement to …

Implementations Of Resilience Engineering For Natural System Disturbances: A Panarchical Perspective, Mark Charles Stone Victoria Jaramillo

Civil Engineering ETDs

This body of work seeks to advance knowledge of resilience and resilience engineering (RE) from a practical and theoretical perspective. Three distinct applications of resilience and RE that align two fundamental frameworks are presented. The first application, a vulnerability assessment, exemplifies the largest scale of panarchy and the measuring aspect of RE. The second application, a Bayesian network approach, exemplifies the intermediate scale of panarchy and the modeling aspect of RE. The third application, an engineering design project using analytical hierarchy process (AHP), exemplifies the smallest scale of panarchy and the building aspect of RE. Studying these applications enriches understanding …

The Development Of A Novel Experiment On Confined, Flattened Brazilian Disks To Correlate Damage And Permeability In Brittle Geo-Materials, Samuel H. Boyce

Civil Engineering ETDs

This research develops a novel experiment using flattened Brazilian disks under confining pressure with concurrent permeability measurements and acoustic emission monitoring. The purpose of this work is to correlate damage and permeability in brittle geo-materials. Two series of tests are performed on concrete and one series on tuff, under a range of confining stresses between 2.76 and 13.79 MPa. Tests were continued beyond peak stress conditions, capturing data in the post-peak region. The acoustic emission data (cumulative energy and counts) are used to identify damage thresholds and track the progression of microscopic damage. This quantified damage is then correlated to …

Biointerfacial Studies Of Nitrifying Biofilms On Physically And Chemically Modified Surfaces, Philip Marley Roveto

Civil Engineering ETDs

Interactions between bacteria and surfaces during the initiation of biofilm formation are complex phenomena with significant and wide-ranging implications for nutrient cycling, ecosystem and human health, and the remediation of anthropogenic pollutants. Nitrifying biofilms are currently used for ammonia removal in wastewater treatment plant (WWTP) systems. As well-studied biofilms, they can serve as models towards understanding crucial aspects of biofilm engineering. The overall objective of this research was to better understand how variations in specific surface chemistries and topographical features affect nitrification rates and microbial populations in an effort to develop technologies for improved productivity. The experimental approach was to …

Recovery Of Gypsum & Magnesium Hydroxide From Brackish Water By Chemical Precipitation, Sugam Tandukar

Civil Engineering ETDs

Exhaust gases from coal combustion contain contaminants such as sulfur dioxide (SO₂) and nitrous oxide (NO_x), and traces of other pollutants such as arsenic (As), mercury (Hg), nitrate (NO₃), and selenium (Se). Exhaust gas scrubbers are used to limit the emissions of these constituents to air. Treating exhaust gases to remove SO₂ is referred to as flue gas desulfurization (FGD), and the most common method is the use of wet scrubbers using limestone slurries. The limestone slurry is recycled multiple times in the scrubber, and to limit the concentration of dissolved constituents, a …

Development Of Mbd Model And Analysis Methodology For Vehicle Design, Alfonso Christopher Ponce

Mechanical Engineering ETDs

This thesis is to provide a new methodology that considers the effects the chassis applies during dynamic load to the suspension and the handling characteristics of a road course vehicle. A methodology in which is described in detail as well as an applied demonstration where literature before this thesis, lacks in replication and serves to establish a basis for multi-body dynamic analysis in this area. Two models to be created, rigid and flexible, and to compare each other to study the effects the chassis torsional stiffness has during load transfer. Ultimately, to assist in the design of a vehicle that …

Experimental Testing Of A 3d-Printed Metamaterial Slow Wave Structure For High Power Microwave Generation, Antonio B. De Alleluia

Electrical and Computer Engineering ETDs

A metamaterial (MTM) high power microwave (HPM) vacuum electron device (VED) was developed using 3D printing technology. The specific geometric pattern of the source can produce both negative permittivity and permeability to interact with a relativistic electron beam. The electron beam is generated using a pulsed electron accelerator with a maximum energy of 700 keV and lasting approximately 16 ns. The design of this novel VED consists of a circular waveguide loaded with complementary split-ring resonators in a linear periodic arrangement in which the relativistic beam travels guided by a magnetic field. The electrons interact with the MTM producing electromagnetic …

Demand Response Management In Smart Grid Networks: A Two-Stage Game-Theoretic Learning-Based Approach, Pavlos Athanasios Apostolopoulos

Electrical and Computer Engineering ETDs

In this diploma thesis, the combined problem of power company selection and Demand Response Management in a Smart Grid Network consisting of multiple power companies and multiple customers is studied via adopting a distributed learning and game-theoretic technique. Each power company is characterized by its reputation and competitiveness. The customers who act as learning automata select the most appropriate power company to be served, in terms of price and electricity needs’ fulfillment, via a distributed learning based mechanism. Given customers' power company selection, the Demand Response Management problem is formulated as a two-stage game theoretic optimization framework, where at the …

Mechanical Characterization Of Additively Manufactured Inconel 625 And Alsi10mg Via High-Throughput Tensile Testing, Aron Robbins

Mechanical Engineering ETDs

Additive manufacturing allows for the development of complex geometrical designs that may otherwise be impossible to fabricate through common methods. This advantage has opened the door to a new testing method capable of rapid and efficient material property characterization and qualification. The technique exhibits how 100’s of sub-size tensile bars can be tested to show an inherent statistical variation of materials produced by laser powder bed fusion. The testing technique presented is used to evaluate various heat treatments of the nickel super-alloy Inconel 625 and the aluminum alloy AlSi10Mg after stress relief annealing. Statistical analysis using 3-parameter Weibull distributions is …

Study Of Distributed Versus Compressed Layouts For Physically Unclonable Functions, Joshua Trujillo

Electrical and Computer Engineering ETDs

Society continues to depend on electronics for everything from smart systems in our homes to cellphones and tablets, which are more powerful today than many desktop computers that are still in use [1]. With increased consumption of these electronic products comes an increase in problems, such as counterfeit integrated circuits being sold as genuine integrated circuits. This is just one of many problems that corporations and end users are having to deal with in this digital age.

Software security has been accepted as a problem by both the media and general public, but only recently has hardware security begun to …

Satisfaction-Aware Data Offloading In Surveillance Systems, Marcos Paul Torres

Electrical and Computer Engineering ETDs

In this thesis, exploiting Fully Autonomous Aerial Systems' (FAAS) and Mobile Edge Computing (MEC) servers' computing capabilities to introduce a novel data offloading framework to support the energy and time-efficient video processing in surveillance systems based on satisfaction games. A surveillance system is introduced consisting of Areas of Interest (AoIs), where a MEC server is associated with each AoI, and a FAAS is flying above the AoIs to support the IP cameras' computing demands. Each IP camera adopts a utility function capturing its Quality of Service (QoS) considering the experienced time and energy overhead to offload and process remotely or …

Artificial Intelligence Empowered Uavs Data Offloading In Mobile Edge Computing, Nicholas Alexander Kemp

Electrical and Computer Engineering ETDs

The advances introduced by Unmanned Aerial Vehicles (UAVs) are manifold and have paved the path for the full integration of UAVs, as intelligent objects, into the Internet of Things (IoT). This paper brings artificial intelligence into the UAVs data offloading process in a multi-server Mobile Edge Computing (MEC) environment, by adopting principles and concepts from game theory and reinforcement learning. Initially, the autonomous MEC server selection for partial data offloading is performed by the UAVs, based on the theory of the stochastic learning automata. A non-cooperative game among the UAVs is then formulated to determine the UAVs' data to be …

Using Uncertainty To Interpret Supervised Machine Learning Predictions, Michael C. Darling

Electrical and Computer Engineering ETDs

Traditionally, machine learning models are assessed using methods that estimate an average performance against samples drawn from a particular distribution. Examples include the use of cross-validation or hold0out to estimate classification error, F-score, precision, and recall.

While these measures provide valuable information, they do not tell us a model's certainty relative to particular regions of the input space. Typically there are regions where the model can differentiate the classes with certainty, and regions where the model is much less certain about its predictions.

In this dissertation we explore numerous approaches for quantifying uncertainty in the individual predictions made by supervised …

Multi-Year Water Quality Data Reveal Highly Variable Timing And Magnitude Of Metabolism And Physicochemical Drivers In An Aridland River Network, Betsy Marie Summers

Civil Engineering ETDs

Streams and rivers process and transport carbon to downstream systems and are important components of global and regional carbon budgets. Ecosystem functions, including gross primary production (GPP) and ecosystem respiration (ER), can be used to improve understanding of carbon cycling and ecosystem health in lotic systems. Whole-stream metabolism (GPP and ER) has been studied extensively in headwater streams. However, we know less about the variability in GPP and ER in aridland rivers and tributary streams despite being globally abundant and vulnerable systems to changing climate. This dissertation explores temporal and spatial variation of GPP and ER in a montane stream …