Engineering Commons^™

Nonlinear Intelligent Model Predictive Control Of Mobile Robots, Benjamin Albia

Theses and Dissertations

This thesis presents a framework for an artificial neural network (ANN) model-based nonlinear model predictive control of mobile ground robots. A computer vision analysis module was first developed to extract quantitative position information from onboard camera feed with respect to a prescribed path. Various strategies were developed to construct nonlinear physical plant models for model predictive control (MPC), including the physics-based model (PBM), the ANN trained on PBM-generated data, the ANN trained on test-captured data, and the ANN initially trained on PBM-generated data and then retrained with captured data. All the models predict physical states and positions of the robot …

Leveraging Digital Transformation To Build The Technology Of Tomorrow Using Yesterday’S Equipment, Evan Barnett

Theses and Dissertations

Today’s industry sectors are filled with machines developed years ago. Healthcare, manufacturing, sustainment operations, and many others have equipment that may be reliable, but lacks certain capabilities that the newest technology delivers. The digital environment is becoming a necessity for users who want greater insights into how to improve their processes. A solution to this problem would be to purchase the newest equipment that contains robust measures to generate, collect, and analyze data. However, this solution may not be financially feasible for some and for others may sacrifice machine downtime and reliability. To combat these issues, this research focuses on …

From The Surface To The Reactor: Identifying The Active Sites For Propane Dehydrogenation On Platinum-Based Catalysts Through Density Functional Theory, Experimental Data, And Uncertainty Quantification, Charles Henry Fricke

Theses and Dissertations

Propane dehydrogenation is a critical process of producing propylene, an important feedstock for the chemical industrial. There are multiple key processes to produce propylene in this manner, but one of the largest processes involves non-oxidative dehydrogenation on a platinum-tin alloy based catalyst. In general, these reactions and catalytic particles are complex, with many dehydrogenation, cracking, and reforming reactions taking place during these processes on multiple surfaces. With this in mind, ab initio computational catalysis models are used to generate further insight into these catalytic processes. In this dissertation, there are three aims to be solved: identifying the most likely active …

The Effect Of Low Dose Penicillin On Tumor Development In ApcMin/+ Mice, Kinsey Ann Sierra Meggett

Theses and Dissertations

Antibiotics have been our most effective weapon against bacterial infections since their discovery in the early 1900s. Their use has been critical in reducing mortality rate from infectious diseases. However, in the last few decades, the overuse of antibiotics, beginning at an early age and into adulthood, has become a growing concern globally. Penicillin is one of many extensively used antibiotics in early childhood that has been used to treat childhood infections. Recent studies showed that exposure to low dose penicillin can have adverse effects leading to chronic illness such as diabetes, allergies, inflammation, and susceptibility to obesity, with the …

The Role Pde11a4 Signaling And Compartmentalization In Social Behavior, Kaitlyn Pilarzyk

Theses and Dissertations

People tend to be social by nature. Being socially connected not only helps people live longer and healthier lives, but being an engaged and contributing member of society strengthens our communities overall. Maintaining intact social behaviors is key to maintaining this wellbeing, with disruptions negatively affecting both mental and physical health. Indeed, social isolation and feelings of loneliness can significantly increase a person’s risk of premature death, heart disease, and stroke as well as depression, anxiety, suicide, and dementia. Maintaining the ability to create and store social memory with age is, therefore, key to maintaining proper social behaviors. Unfortunately, individuals …

Recent Advances In Catalytic Ethylene Epoxidation: Synthesis, Characterization, And Evaluation, Benjamin Thomas Egelske

Theses and Dissertations

First synthesized in 1859 by French chemist Charles-Adolphe Wurtz, ethylene oxide (EO) is produced from the direct epoxidation of ethylene and molecular oxygen over a low surface area α-Al₂O₃ supported silver (Ag) catalyst [1-6]. With a production capacity over 35 Mt/year, EO is the largest chemical by volume synthesized from a heterogeneously catalyzed process and is used in the production of ethylene glycol, ethoxylates, and ethanolamines [6, 7]. State-of-the-art catalyst formulations contain high loadings of Ag, typically 12-30wt%, required to recover activity in the presence of promoter elements which increase EO selectivity from ~75% for unsupported Ag to 80% for …

Impact Of Graphene On Microstructure And Compressive Strength Of Cement Mortars Utilizing Two Different Dispersion Methods, Elhussien Khaled Elbatanouny

Theses and Dissertations

Carbon-based nanomaterials are currently used to reinforce cement-based composite materials based on their superior properties. This study investigates the mechanical property (compressive strength) of cement mortars incorporated with pristine graphene. The dosages of graphene materials used were 0.01%, 0.02%, 0.03%, and 0.04% by weight of cement. Moreover, this study compares two dispersion techniques: ultrasonication with surfactant coating and mechanical blending with surfactant coating to promote the use of graphene in cement mortars. A commonly used polycarboxylate superplasticizer Sika-Viscocrete Ultra 2100, was used as a dispersant agent (surfactant) of graphene with a surfactant to graphene weight ratio of 9 to 1. …

Structure And Stability Of Ag-Ir Bimetallic Catalysts Prepared By Electroless Deposition And Synthesis And Performance Of High Selectivity Movnbsbteox Mixed Oxides For Oxidative Dehydrogenation Of Ethane, Mozhdeh Parizad

Theses and Dissertations

Improvements in industrial thermal conversions can be realized through comprehensive catalytic studies, where enhanced catalyst stability and activity are desired. Catalyst performance can be greatly affected by structural changes at high temperatures. In the case of supported Ag-Ir particles, the surface free energy (SFE) can determine preferred arrangement of the component metals. The well-established methods of strong electrostatic adsorption (SEA) and electroless deposition (ED) have been used to synthesize highly-dispersed Ag/Ir on different alumina supports (δ,θ-Al2O3 and γ-Al2O3). Surface thermodynamics dictate that the Ir-Ag system should conform to minimize free energy resulting in a low SFE Ag layer localized on …

Predicting Pavement Structural Condition Using Machine Learning Methods, Nazmus Sakib Ahmed

Theses and Dissertations

State departments of transportation recognize the need to incorporate pavement structural condition in their pavement performance models and/or decision processes used to select candidate projects for preservation, rehabilitation, or reconstruction at the network level. However, pavement structural condition data are costly to obtain. To this end, this paper develops and evaluates the effectiveness of two machine learning methods, Random Forest (RF) and eXtreme Gradient Boosting (XGBoost), for predicting a flexible pavement’s structural condition. The aim is to be able to predict whether a pavement section’s structural condition is poor or not based on Annual Average Daily Traffic (AADT), truck percentage, …

Identification Of Structural Signature Responses From Response Time Histories Using B-Spline Impulse Response Techniques, Shadhan Ahmed Al Kharusi

Theses and Dissertations

Structure Health Monitoring (SHM) is an essential practice for ensuring the safety of people and the structures itself. For this purpose, variety of global and local damage detection methods have been used to investigate damages. Global damage detection focus on identifying damage in early stages while local damage detection related to damage location, severity, and prediction of the remaining of the structure. Any damage in structure leads to a change to the properties and characteristics of the dynamic response.

Existing methods uses modal-based and response-based for damage detection. Both have several shortcoming associate with sensitivity of the damage and measurement …

Development Of A First-Generation Prototype Laboratory System For Rail Neutral Temperature Measurements, Ellie Yi-Hsien Chao

Theses and Dissertations

Modern railway tracks worldwide standardize the use of Continuous Welded Rail (CWR) due to its ability to prevent disadvantages associated with rail joints in a track. CWR is laid when the rail is free of thermal stresses, also known as Rail Neutral Temperature (RNT). RNT is controlled in the CWR installation procedure; however, over time, the temperatures deviate from the RNT. The deviation causes significant thermal stresses introduced in the longitudinal direction of the rail, leading to potential failures such as pull-apart and buckling, causing track integrity and safety of train operation. The most significant potential failure is track buckling …

Fabrication And Characterization Of Micro/Nanostructured Ceramic Device For Energy Conversion, Yun Gan

Theses and Dissertations

The deteriorating climate is threatening our living habitat and arousing public awareness. To achieve the carbon neutral goal by the middle of 21st century, developing novel technologies to reduce CO₂ emission or promote its capture become urgent. Among them, oxygen permeation membrane (OPM) and solid oxide cell (SOC) are two promising devices for clean energy conversion.

In chapter 1, the background of OPM and SOC are briefly introduced. Fundamental mechanism and application of phase inversion, the key process involved in fabrication of hollow fiber OPM and microtubular SOC are emphatically described. Mixed ionic and electronic conducting (MIEC) perovskites demonstrate …

Increased Detectivity And Low Temperature Performance Analysis Of Sub-20Μm Micropixel Array A1gan Uv Photodiodes, Samia Islam

Theses and Dissertations

This thesis is divided into two sections. At first, we demonstrate ~1.5x detectivity increase in AlGaN photodiodes on sapphire using distributed micropixel arrays with 5-15 µm pixel diameter. This is due to the ~10x larger chip footprint of the 5um diameter micropixel arrays compared to planar control structures with identical p contact area. The responsivity of the larger areas was the same as that of the control structure despite the larger footprint while the dark currents, an indicator of noise, remained unchanged. The photocurrent generated between pixels was collected due to transmission line effects connecting the pixels separated by 5um, …

Robot Area Coverage Path Planning In Aquatic Environments, Nare Karapetyan

Theses and Dissertations

This thesis is motivated by real world problems faced in aquatic environments. It addresses the problem of area coverage path planning with robots - the problem of moving an end-effector of a robot over all available space while avoiding existing obstacles. The problem is considered first in a 2D space with a single robot for specific environmental monitoring operations, and then with multi-robot systems — a known NP-complete problem. Next we tackle the coverage problem in 3D space - a step towards underwater mapping of shipwrecks or monitoring of coral reefs.

The first part of this thesis leverages human expertise …

Hydrodeoxygenation Of Biomass Derived Sugar Alcohols To Platform Chemicals Using Heterogeneous Catalysts, Blake Macqueen

Theses and Dissertations

This work set out to investigate biomass derived sugar alcohol upgrading via the removal of oxygen and hydroxyl groups via the hydrodeoxygenation reaction utilizing heterogeneous catalysts. The importance of reaction conditions, catalyst meal loadings, catalyst structure and properties were probed using techniques such as design of experiments, and spectroscopic techniques including Raman and DRIFTS. The state of the art simultaneous hydrodeoxygenation (S-HDO) catalyst ReO_x-Pd/CeO₂ was investigated and optimized for various sugar alcohol substrates. The kinetics and associated mass transfer were also investigated to give further insight into the reaction over the ReO_xPd/CeO₂ catalyst.

First, …

Ultrawide Bandgap Algan-Channel Metal Oxide Semiconductor Heterostructure Field Effect Transistors With High-K Gate Dielectrics, Md Abu Shahab Mollah

Theses and Dissertations

Ultra-wide Band Gap (UWBG) (E_G > 3.4 eV) Al_xGa_1-xN channel devices are promising candidates for compact next-generation power electronics due to the scaling of the breakdown field with alloy composition. The huge opportunity in consumer electronics is the major driving force behind the recent developments of UWBG AlGaN-channel HEMTs. One of the most critical issues limiting the device performance at high power level is device degradation primarily caused by gate leakage current. Use of SiO₂ gate insulator is a standard method to suppress gate leakage but it causes threshold voltage shift towards more negative requiring …

Development Of A Multi-Scale Mechano-Electrochemical Battery Model, Drew J. Pereira

Theses and Dissertations

As the automotive industry moves towards large format electric vehicles, such as trucks and SUVs, the need for highly efficient, energy-dense electrodes rapidly increases. Several promising active materials have been studied and proposed, however, many of these materials undergo significant volume change upon lithiation and de-lithiation. Cell and pack designers struggle to understand and predict how active material volume change at the particle scale will affect mechano-electrochemical behavior on the electrode, cell, and pack scales. Additionally, many of these active materials suffer in their cycle life due to a mechanically-driven degradation of the electrode matrix. Therefore, the focus of this …

Catalytic And Non-Catalytic Methods For Hydrocarbon Upgrading, Valorization, And Pollutant Control, Michael Morgan Royko

Theses and Dissertations

This work investigates catalytic and non-catalytic oxidative chemical upgrading and pollutant remediation techniques to responsibly utilize hydrocarbon feedstocks with existing infrastructure as the transition to more renewable and cleaner feedstocks for energy generation are developed. These technologies include oxidative dehydrogenation of ethane, development of magnetically separable catalysts to reduce carbon monoxide emissions during biomass upgrading as well as the subsequent use of the upgraded biomass for partial coal replacement, and electrochemical treatment of a washcoat free wire mesh supported catalyst to reduce carbon monoxide emissions in combustion exhaust.

First, doping of secondary metals in M1/M2 catalysts for oxidative dehydrogenation of …

Fate And Transport Of The Microbiome In Built Environments, Dahae Seong

Theses and Dissertations

Buildings are complex ecosystems evolving continuously. Indoor components such as occupants, ventilation system, and building structures influence the microbiome. To shed light on how the microbial population in a building will respond to such a fluid system, the fundamental interactions between microbes and the indoor ecosystem must be understood. Buildings are being designed as air-tight structures to save energy; however, this could lead to degradation of indoor air quality through indoor sources of contaminants and/or containment of pollutants in the room or introduce outdoor pollutants indoors depending on the ventilation conditions. In addition, transmission of infectious microbes in indoors threaten …

Shape-Selective Silver Catalysts For Ethylene Epoxidation, Kaveh Shariati

Theses and Dissertations

Epoxidation of ethylene with oxygen over promoted silver catalyst is one of the most important examples of heterogeneous catalysis to date with a multi-billion dollar annual market. Ethylene oxide (EO) can be used directly as a sterilizer, disinfectant, and fungicide, or as an intermediate chemical for producing ethylene glycol, detergents, antifreeze, polyesters, as well as a variety of other commercial chemicals. Thus, ethylene oxide is known as one of the highest volume chemicals produced in the chemical industry, accounting for approximately 40-50% of the total value of organic chemicals produced by heterogeneous oxidation. Considering the application of EO in detergents …

Multi-Fidelity Surrogate And Reduced-Order Model-Based Microfluidic Concentration Gradient Generator Design, Haizhou Yang

Theses and Dissertations

The microfluidic concentration gradient generator (μCGG) is an important device to generate and maintain concentration gradients (CGs) of biomolecules for understanding and controlling biological processes. However, determining the optimal operating parameters of μCGG is still a significant challenge, especially for complex CGs in cascaded networks. To tackle such a challenge, this study presents multi-fidelity surrogate and reduced-order model-based optimization methodologies for accurate and computationally efficient design of μCGGs.

The surrogate-based optimization (SBO) method is first proposed for the design optimization of μCGGs based on an efficient physics-based component model (PBCM). Various combinations of regression and correlation functions in Kriging and …

Quantifying And Elucidating The Effect Of Co2 On Aemfcs, Yiwei Zheng

Theses and Dissertations

Anion exchange membrane fuel cells (AEMFCs) have recently received significant attention as a future high efficiency, environmentally friendly energy conversion device. This attention is due to the potential advantages that AEMFCs can offer compared the much more common, and commercialized, proton exchange membrane fuel cells (PEMFCs) – most notably lower cost. However, there are several remaining roadblocks for the AEMFC technology to be widely adopted, such as: i) the stability of the anion exchange membranes (AEMs) and anion exchange ionomer (AEIs); ii) the development of highly active catalysts with either low platinum group metal (PGM) loading or catalysts that are …

Intelligent Optimization Algorithm-Based Path Planning For A Mobile Robot, Qisong Song, Shaobo Li, Jing Yang, Qiang Bai, Jianjun Hu, Xingxing Zhang, Ansi Zhang

Faculty Publications

The purpose of mobile robot path planning is to produce the optimal safe path. However, mobile robots have poor real-time obstacle avoidance in local path planning and longer paths in global path planning. In order to improve the accuracy of real-time obstacle avoidance prediction of local path planning, shorten the path length of global path planning, reduce the path planning time, and then obtain a better safe path, we propose a real-time obstacle avoidance decision model based on machine learning (ML) algorithms, an improved smooth rapidly exploring random tree (S-RRT) algorithm, and an improved hybrid genetic algorithm-ant colony optimization (HGA-ACO). …

Recent Development Of Unpowered Exoskeletons For Lower Extremity: A Survey, Tao Liu, Bin Zhang, Bin Zhang, Micheal G. Pecht

Faculty Publications

Unpowered exoskeletons (UEs) have attracted extensive research attentions for their portability, handleability and simplicity. However, designing exoskeletons without any active actuators is a great challenge because essential criteria such as performance enhancement, low impedance, and comfort must be met. This paper reviews the UEs researches from three aspects including modeling for understanding gait pattern, mechanical designs, and validation methods, which are main considerations of designing UEs. This review is based on the reported works in the past two decades and underlines some practical opportunities and challenges. Statistical data analysis and critical reviews are stated to understand human gait patterns, designing …

Emr: A New Metric To Assess The Resilience Of Directional Mmwave Channels To Blockages, Faith Erden, Ozgur Ozdemir, Ismail Guvenc, David W. Matolak

Faculty Publications

Millimeter-wave (mmWave) communication systems require narrow beams to compensate for high path loss and to increase the communication range. If an obstacle blocks the dominant communication direction, alternative paths (directions) should be quickly identified to maintain reliable connectivity. In this paper, we introduce a new metric to quantify the Effective Multipath Richness (EMR) of a directional communication channel in the angular domain. In particular, the proposed metric takes into account the strength and spatial diversity of the resolved Multipath Components (MPCs), while also considering the beamwidth of the communication link and the blockage characteristics. The metric is defined as a …

Drone-Based Vibration Monitoring And Assessment Of Structures, Sabrina Carroll, Joud Satme, Shadhan Alkharusi, Nikolaos Vitzilaios, Austin Downey, Dimitris Rizos

Faculty Publications

This paper presents a novel method of procuring and processing data for the assessment of civil structures via vibration monitoring. This includes the development of a custom sensor package designed to minimize the size/weight while being fully self-sufficient (i.e., not relying on external power). The developed package is delivered to the structure utilizing a customized Unmanned Aircraft System (UAS), otherwise known as a drone. The sensor package features an electropermanent magnet for securing it to the civil structure while a second magnet is used to secure the package to the drone during flight. The novel B-Spline Impulse Response Function (BIRF) …

Investigating Influence Of Geometry And Operating Conditions On Local Current, Concentration, And Crossover In Alkaline Water Electrolysis Using Computational Fluid Dynamics, J. S. Lopata, S-G. Kang, H-S. Cho, C-H. Kim, J. W. Weidner, Sirivatch Shimpalee

Faculty Publications

We use a three-dimensional computational fluid dynamics model to examine the liquid saturation, KOH concentration, and gas crossover in an alkaline diaphragm water electrolysis device. The effects of cell potential, solution feed rate, and aspects of the design such as the locations and widths of channels on performance and crossover were studied. The results build a case for implementing a separator transport model and an electrode/separator interface model because of the concentration changes observed at the anode and cathode. Simulations suggest a strong relationship between solution feed rate and the nature of dissolved gas crossover through the diaphragm due to …

Fourth-Order Adjoint Sensitivity And Uncertainty Analysis Of An Oecd/Nea Reactor Physics Benchmark: I. Computed Sensitivities, Ruixian Fang, Dan Gabriel Cacuci

Faculty Publications

This work extends the investigation of higher-order sensitivity and uncertainty analysis from 3rd-order to 4th-order for a polyethylene-reflected plutonium (PERP) OECD/NEA reactor physics benchmark. Specifically, by applying the 4th-order comprehensive adjoint sensitivity analysis methodology (4th-CASAM) to the PERP benchmark, this work presents the numerical results of the most important 4th-order sensitivities of the benchmark’s total leakage response with respect to the benchmark’s 180 microscopic total cross sections, which includes 180 4th-order unmixed sensitivities and 360 4th-order mixed sensitivities corresponding to the largest 3rd-order ones. The numerical results obtained in this work reveal that the number of 4th-order relative sensitivities that …

A Cdzntese Gamma Spectrometer Trained By Deep Convolutional Neural Network For Radioisotope Identification, Sandeep K. Chaudhuri, Joshua W. Kleppinger, Ritwik Nag, Kaushik Roy, Rojina Panta, Forest Agostinelli, Amit Sheth, Utpal N. Roy, Ralph B. James, Krishna C. Mandal

Publications

We report the implementation of a deep convolutional neural network to train a high-resolution room-temperature CdZnTeSe based gamma ray spectrometer for accurate and precise determination of gamma ray energies for radioisotope identification. The prototype learned spectrometer consists of a NI PCI 5122 fast digitizer connected to a pre-amplifier to recognize spectral features in a sequence of data. We used simulated preamplifier pulses that resemble actual data for various gamma photon energies to train a CNN on the equivalent of 90 seconds worth of data and validated it on 10 seconds worth of simulated data.

Bright And Blind Spots Of Water Research In Latin America And The Caribbean, Alyssa J. Devincentis, Hervé Guillon, Romina Díaz Gómez, Noelle K. Patterson, Francine Van Den Brandeler, Srthur Koehl, Pablo Ortiz-Partida, Laura E. Garza-Díaz, Jennifer Gamez-Rodríguez, Erfan Goharian, Samuel Sandoval Solis

Faculty Publications

Water resources management in Latin America and the Caribbean is particularly threatened by climatic, economic, and political pressures. To assess the region's ability to manage water resources, we conducted an unprecedented literature review of over 20 000 multilingual research articles using machine learning and an understanding of the socio-hydrologic landscape. Results reveal that the region's vulnerability to water-related stresses, and drivers such as climate change, is compounded by research blind spots in niche topics (reservoirs and risk assessment) and subregions (Caribbean nations), as well as by its reliance on an individual country (Brazil). A regional bright spot, Brazil, produces well-rounded …