Engineering Commons^™

Tracking, Detection And Registration In Microscopy Material Images, Hongkai Yu

Theses and Dissertations

Fast and accurate characterization of fiber micro-structures plays a central role for material scientists to analyze physical properties of continuous fiber reinforced composite materials. In materials science, this is usually achieved by continuously crosssectioning a 3D material sample for a sequence of 2D microscopic images, followed by a fiber detection/tracking algorithm through the obtained image sequence.

To speed up this process and be able to handle larger-size material samples, we propose sparse sampling with larger inter-slice distance in cross sectioning and develop a new algorithm that can robustly track large-scale fibers from such a sparsely sampled image sequence. In particular, …

Dynamic Simulation Of A Solar Powered Hybrid Sulfur Process For Hydrogen Production, Satwick Boddu

Theses and Dissertations

The Hybrid Sulfur process is a thermo-electrochemical cycle used to produce hydrogen from water. The process requires a high temperature energy source for H2SO4 decomposition with temperature reaching 800°C. This step is followed by SO2 - depolarized water electrolysis. Using solar energy as the high temperature energy source allows for efficient environmentally friendly production of hydrogen. This method is an alternative to traditional photovoltaic electrolysis for hydrogen production. Making the process economically competitive is a major challenge. Operating the process with changes in the availability of solar energy also increases process complexity. The dependence of the process on solar energy …

Computations Of The Dynamic Fracture Of Plane Structures By The Extended Finite Element Method, Iman Asareh

Theses and Dissertations

Finite element methods for the simulation of dynamic fracture in plane structures are presented. The method is a modified extended finite element method (XFEM) for dynamic fracture simulations with a new methodology to construct the XFEM basis functions for discontinuities. In contrast to conventional XFEM in which the extended interpolation is defined to only capture the discontinuities, the proposed method describes the enrichment functions so that they reproduce both the discontinuities and the polynomial bases of sufficiently high order which are critical for finite element convergence. Such enrichment functions, by adopting the Duffy’s transformation, can be simply defined in terms …

Effect Of Material Orientation On The Impact Response Of Graded Cellular Materials, Abigail Wohlford

Theses and Dissertations

In this study, the effect of layer stacking on the energy absorption characteristics of density-graded cellular polymers subjected to high velocity impact is investigated experimentally. The focus in the present work is to characterize the constitutive response and deformation mechanisms of these Functionally Graded Foam Materials (FGFM) using full-field measurements. Uniform foam Quasi-static and dynamic testing of uniform foam specimens are completed for each nominal density used in the layered foam samples. The low strain-rate experiments are performed in order to determine the mechanical properties of foam specimens. The high-rate experiments for homogenous foam specimens were completed to further characterize …

A Comprehensive Reengineering Of The Hospital Emergency Triage System, Nicholas D. Boltin

Theses and Dissertations

Hospital emergency triage and specifically Mass Casualty Incidents (MCIs) are of major concern with regard to treatment and patient outcomes. Traditional emergency department triage models are oversimplified and often lead to over/under triaging of patients. Furthermore, triage models do not account for the full spectrum of different types of MCIs which often results in misclassification. In this thesis, we begin by looking at traditional triage models currently being used in hospital systems and identify several shortcomings of using these models within the context of a chemical related MCI. I will then move to describe a new approach to creating a …

Characterization Of Evaporation/Condensation During Pool Boiling And Flow Boiling, Mostafa Mobli

Theses and Dissertations

Present dissertation has investigated pool and flow boiling and their characteristics via numerical means. A code was developed to investigate and enhance heat transfer performance during different modes of phase change phenomena. Multiphase heat transfer has proven to be one of the most effective means of heat transfer in different industries, therefore, there have been numerous experimental and numerical studies on the subject of phase change phenomena in a wide range of conditions and setups; yet there are complex bubble dynamics and heat transfer characteristics that remain unresolved. To have a more detailed look at and a better understanding of …

Acoustic Emission Detection In 304h Stainless Steel Due To Intergranular Stress Corrosion Cracking, Joseph W. Hill

Theses and Dissertations

Storage of spent nuclear fuel has become problematic in past decades due to delayed completion of long-term repositories for various reasons. Temporary storage containers called Dry Cask Storage Systems (DCSS) made of stainless-steel and surrounded by reinforced concrete have been in use but are exceeding their designed usage periods. Defects in canisters can be exacerbated in climates susceptible to high humidity and salinity levels. As inspection and relicensing of DCSS increases, more efficient monitoring techniques could save nuclear facilities valuable time and resources. Crack detection of the canister walls or welds in real time may be possible utilizing acoustic emission …

Acousto-Ultrasonic Shm/Nde Methods Toward Field Application, Stephen Harris Howden

Theses and Dissertations

Acousto-ultrasonic nondestructive evaluation (NDE) and structural health monitoring (SHM) methods offers solutions in damage detection, material properties evaluation and more. These ultrasonic waves can propagate through solids and interact with structural features and discontinuities. In this thesis use of several acousto-ultrasonics NDE/SHM methods were explored to evaluate their sensing and detection capabilities toward damage detection field applications in nuclear and aerospace industries.

For nuclear applications, passive sensing using piezoelectric sensors and acoustic emission (AE) techniques were explored on the spent fuel dry storage casks. Dry storage casks are used in the nuclear industry to transport or store spent nuclear fuel …

The Mechanical Properties And Deformation Behavior Of Heat Treated Versus As-Received Inconel X-750, Christopher Marsh

Theses and Dissertations

X-750 is a nickel-chromium based super alloy of usefulness in a wide variety of applications such as gas turbines, rocket engines, nuclear reactors, pressure vessels, tooling, and aircraft structures. Its good mechanical properties are due to the strengthening from precipitation of γ′ particles upon prior ageing heat treatment. In this work, the effect of such heat treatment on the mechanical properties, tensile behavior, and fracture mechanisms of X-750 was studied at various temperatures by comparing it with a non-aged, solution annealed X-750. Tensile tests were conducted from room temperatures up to 900 °C at three separate strain rates (10-3, 10-4, …

Structural Health Monitoring Using Ultrasonic Guided Waves And Piezoelectric Wafer Active Sensors, Faisal Haider Mohammad

Theses and Dissertations

This dissertation is organized in three major parts covering ardent and challenging research topics in structural health monitoring (SHM). Part I focuses on the theoretical and numerical analysis of acoustic emission (AE) guided waves in both Cartesian coordinates (2D) and cylindrical coordinates (3D) system using energy approach, which, to the best of our knowledge, has not been yet reported elsewhere. AE guided waves appear due to sudden energy release during incremental crack propagation in a plate. The Helmholtz decomposition approach is applied to the inhomogeneous elastodynamic Navier-Lame equation for both the displacement field and body forces. For the displacement field, …

Changes In Nadph Oxidase (Nox) Protein Isoforms And Downstream Reactions As Function Of Time And Overpressure In Blast Tbi, Smit Prakash Shah

Theses

Blast-induced Traumatic brain injury (bTBI) is a leading cause of morbidity in soldiers on the battlefield and training sites with long-term neurological and psychological pathologies. Among many pathological sequela of blast TBI, oxidative stress has been identified as a major factor contributing to the pathophysiology of bTBI. Recent studies have demonstrated activation of oxidative stress pathways following blast injury but their distribution among different brain regions as function of post injury time and Blast over pressure (BOP) have not been explored. The present study examines the protein expression of NADP oxidase (NOX) isoforms 1 & 2, corresponding superoxide production, a …

The Rational Synthesis Of Bimetallic Catalysts On Oxide Supports, Andrew Phillip Wong

Theses and Dissertations

Catalysts play an important role in many chemical reactions. However, simple impregnated monometallic catalysts are often limited in their function. One way to overcome this limitation is through the incorporation of a secondary metal to the catalysts. These bimetallic catalysts often have synergistic benefits not observed in the monometallic analogues. Here, we focused on the synthesis of bimetallic catalysts using rational methods in order to improve catalyst function; specifically by tuning the particle size, morphology, and composition. The two methods of interests were Strong Electrostatic Adsorption (SEA) and Electroless Deposition (ED). An adaptation of SEA to bimetallic catalysts (coSEA) was …

Nondestructive Evaluation Of Corrosion Damage In Reinforced Concrete Aged Slab Specimen, Rawya Abdulsattar Abduljabbar

Theses and Dissertations

The deterioration of concrete bridge decks presents a maintenance challenge for most transportation agencies and bridge owners. This problem increases during the freeze-thaw cycle. De-icing salts can accelerate the deterioration process. Corrosion of steel reinforcement in reinforced concrete structures is considered a dominant factor causing premature deterioration, especially those structures located in a coastal environment. The resulting corrosion product produced has several times the volume of steel, resulting in cracking of the concrete cover if the corrosion is significant. In this study, a bridge deck specimen was subjected to an artificial environment to accelerate the corrosion process. Prior to this …

Monitoring The Progress Of Damage In A Sicf-Sicm Composite Nuclear Fuel Cladding Under Internal Pressure Using Acoustic Emission, Luis H. Alva

Theses and Dissertations

The relation between the progress of damage and the acoustic emission (AE) activity of a nuclear grade Sif-SiCm composite tubing under internal pressure was studied. The nuclear grade Sif-SiCm composite tubing is manufactured by the company General Atomics (GA) and made of nuclear grade HI Nicalon type S fiber preforms following a chemical vapor infiltration (CVI) technique. Sif-SiCm composites are good candidates to replace current nuclear fuel cladding materials because of the good chemical stability and strength at high temperatures. In this work, a Sif-SiCm composite tubing was tested under internal pressure at room temperature (RT) to study the damage …

Multifunction Radio Frequency Composite Structures, David L. Zeppettella

Theses and Dissertations

There has been recent interest in the development of multifunction structures for weight-critical applications. A multifunction structure is a load-bearing structure that also allows one or more additional functions such as RF communication, energy storage, sensing etc. The focus of this dissertation is to analyze, design, develop, and test new high performance (broadband, high gain, circularly polarized) internal antennas that are structural and integral to the aircraft. It is demonstrated that antennas with more bandwidth and higher efficiency could be developed if the space and materials available in an aircraft structure could be judiciously exploited for multifunctional usage. This is …

Association Between Mechanics And Biology In Vascular Graft Remodeling, David Andrew Prim

Theses and Dissertations

Coronary artery bypass grafting (CABG) restores myocardial perfusion in patients with severe coronary artery disease by utilizing autografts – usually at least one of the internal thoracic artery (ITA), radial artery (RA), and great saphenous vein (GSV) – to bypass stenosed regions of coronary arteries. While decades of research and clinical improvements have made CABG an indispensable procedure, tens of thousands of grafts fail each year, which is due, at least in part, to an inability of the source vessels to adapt to the altered stimuli of the coronary circulation. In this dissertation, we first quantify and compare the mechanical …

Development Of Advanced Mixed Electronic And Carbonate Ion Conducting Membranes And Reactors For Combined Co2 Capture And Conversion, Jie Fang

Theses and Dissertations

Global warming and climate change resulted from CO2 emissions have been increasingly observed to impact our daily life and damage our economy in recent human history. To deal with this grand challenge, carbon capture and storage (CCS) has been established as a key technology to curb CO2 emission from fossil-fueled power plants. The core of the CCS technology is to capture CO2 at emission sources and geologically bury it for permanent storage or enhanced oil recovery (OER). As the first step of CCS, carbon capture technologies are currently being developed for three power-generation related combustion processes that are responsible for …

Role Of Mammary Microenvironment In Promoting Left-Right Differences In Tumor Progression, Metastasis, And Therapeutic Response, Huda Issa Atiya

Theses and Dissertations

Metastasis is the main cause of death in breast cancer patients; however, there are currently no treatments available to treat or prevent metastasis. This is in part because regulators of metastasis are not yet fully understood. Over the past century researchers began to study metastasis regulators by different hypotheses, such as the seed and soil hypothesis which focuses on studying the role of cancer cells, the seeds, and the tissue microenvironment, the soil, in regulating metastasis. Although lots of studies have focused on the microenvironment of metastatic sites and their roles in regulating metastasis, limited studies have focused on the …

Magnetron Sputtering Of Nb3Sn For Srf Cavities, Md. N. Sayeed, H. Elsayed-Ali, G. V. Eremeev, M. J. Kelley, U. Pudasaini, C. E. Reece

Electrical & Computer Engineering Faculty Publications

Nb₃Sn is a potential candidate for surface material of SRF cavities since it can enable the cavity to operate at higher temperatures with high quality factor and at an increased accelerating gradient. Nb-Sn films were deposited using magnetron sputtering of individual Nb and Sn targets onto Nb and sapphire substrates. The as-deposited films were annealed at 1200 °C for 3 hours. The films were characterized for their structure by X-ray Diffraction (XRD), morphology by Field Emission Scanning Electron Microscopy (FESEM), and composition by Energy Dispersive X-ray Spectroscopy (EDS) and Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS). The …

Fliess Operator Representations Of Markov Jump Nonlinear Systems And Their Parallel Interconnections, Luis A. Duffaut Espinosa, W. Steven Gray

Electrical & Computer Engineering Faculty Publications

This paper provides a Fliess operator representation for a class of continuous-time Markov jump nonlinear systems. This representation allows one to describe the parallel sum and product interconnections of such systems. The paper concludes by showing that all parallel interconnections preserves rationality when the component operators have rational generating series.

Dynamic Output Feedback Invariants Of Full Relative Degree Nonlinear Siso Systems, W. Steven Gray, Luis A. Duffaut Espinosa

Electrical & Computer Engineering Faculty Publications

The goal of this paper is to explicitly describe invariants of a plant described by a Chen--Fliess series under a class of dynamic output feedback laws using earlier work by the authors on feedback transformation groups. The main result requires the rather strong assumption that the plant has a generating series with both finite Lie rank and full relative degree. In which case, there is no loss of generality in working with state space realizations of the plant. An additional genericness assumption regarding the normal form of the plant is also required, but as shown by the examples, this condition …

High Sensitivity Optical Fiber Interferometric Sensors, Dejun Liu

Doctoral

Optical fiber interferometers have been widely employed and investigated for monitoring the changes in both physical and chemical parameters, with the advantages of compact size, light weight, immunity to electromagnetic interference, high sensitivity, capability to work in harsh environments and remote operation capabilities. Among the different kinds of fiber sensors based on interferometry, singlemode-multimode-singlemode (SMS) structures has attracted considerable interest due to their inherent advantages of high sensitivity, ease of fabrication and interconnection to other fiber systems and low cost. However, the challenge is that the sensitivity of the traditional SMS based fiber structure is not sufficient in some cases, …

On The Application Of Pspice For Localised Cloud Security, Paul Tobin

Doctoral

The work reported in this thesis commenced with a review of methods for creating random binary sequences for encoding data locally by the client before storing in the Cloud. The first method reviewed investigated evolutionary computing software which generated noise-producing functions from natural noise, a highly-speculative novel idea since noise is stochastic. Nevertheless, a function was created which generated noise to seed chaos oscillators which produced random binary sequences and this research led to a circuit-based one-time pad key chaos encoder for encrypting data. Circuit-based delay chaos oscillators, initialised with sampled electronic noise, were simulated in a linear circuit simulator …

A Proposal For A Technological Solution To Improve User Experience In A Shopping Center Based On Indoor Geolocation Services, Luinel Andrade, Johan Quintero, Eric Gamess, Antonio Russoniello

Research, Publications & Creative Work

For shopping centers, mobile devices and their associated technologies represent great business opportunities and a way to improve the user experience within their facilities. These types of constructions are usually quite large, multi-story, and with a significant number of shops, services, where the visitors may find themselves having difficulties to have a complete and up-to-date list of the stores, determine which stores and services are those that meet the characteristics or specifications they seek, know the location of the shops or how to reach them. This research studies and contemplates different technologies, tools, and approaches for the development of a …

Transient Lattice Deformations Of Crystals Studied By Means Of Ultrafast Time-Resolved X-Ray And Electron Diffraction, Runze Li, Kyle Sundqvist, Jie Chen, H. E. Elsayed-Ali, Jie Zhang, Peter M. Rentzepis

Electrical & Computer Engineering Faculty Publications

Ultrafast lattice deformation of tens to hundreds of nanometer thick metallic crystals, after femtosecond laser excitation, was measured directly using 8.04 keV subpicosecond x-ray and 59 keV femtosecond electron pulses. Coherent phonons were generated in both single crystal and polycrystalline films. Lattice compression was observed within the first few picoseconds after laser irradiation in single crystal aluminum, which was attributed to the generation of a blast force and the propagation of elastic waves. The different time scales of lattice heating for tens and hundreds nanometer thick films are clearly distinguished by electron and x-ray pulse diffraction. The electron and lattice …

Manufacturing Applications Of The One-Dimensional Cutting Stock Problem As A Team Project, Hüseyin Sarper, Nebojsa I. Jaksic

Electrical & Computer Engineering Faculty Publications

This paper explains the beneficial and practical impact of operations research in two real manufacturing settings. Two manufacturing examples used in student projects were (1) cutting rails (80‘ or 40‘) to manufacture railroad frogs of many sizes and (2) cutting round metal rolls (12‘ to 20‘) to meet customer demands for various lengths of cuts. Student teams in Engineering of Manufacturing Processes and Operations Research courses wrote computer programs. The program first identified all possible patterns that can be cut out of a given stock length. Next, the program created a mathematical model (a text file) as an output. This …

Real Time Spectroscopic Ellipsometry Analysis Of First Stage Cuin1-Xgaxse2 Growth: Indium-Gallium Selenide Co-Evaporation, Puja Pradhan, Puruswottam Aryal, Dinesh Attygalle, Abdel-Rahman Ibdah, Prakash Koirala, Jian Li, Khagendra P. Bhandari, Geethika K. Liyanage, Randy J. Ellingson, Michael J. Heben, Sylvain Marsillac, Robert W. Collins, Nikolas J. Podraza

Electrical & Computer Engineering Faculty Publications

Real time spectroscopic ellipsometry (RTSE) has been applied for in-situ monitoring of the first stage of copper indium-gallium diselenide (CIGS) thin film deposition by the three-stage co-evaporation process used for fabrication of high efficiency thin film photovoltaic (PV) devices. The first stage entails the growth of indium-gallium selenide (In_1-xGa_x)₂Se₃ (IGS) on a substrate of Mo-coated soda lime glass maintained at a temperature of 400 °C. This is a critical stage of CIGS deposition because a large fraction of the final film thickness is deposited, and as a result precise compositional control is desired in order to …

Assessment Of Spatiotemporal Fusion Algorithms For Planet And Worldview Images, Chiman Kwan, Xiaolin Zhu, Feng Gao, Bryan Chou, Daniel Perez, Jinag Li, Yuzhong Shen, Krzysztof Koperski, Giovanni Marchisio

Electrical & Computer Engineering Faculty Publications

Although Worldview-2 (WV) images (non-pansharpened) have 2-m resolution, the re-visit times for the same areas may be seven days or more. In contrast, Planet images are collected using small satellites that can cover the whole Earth almost daily. However, the resolution of Planet images is 3.125 m. It would be ideal to fuse these two satellites images to generate high spatial resolution (2 m) and high temporal resolution (1 or 2 days) images for applications such as damage assessment, border monitoring, etc. that require quick decisions. In this paper, we evaluate three approaches to fusing Worldview (WV) and Planet images. …

Fast Identification Of High Utility Itemsets From Candidates, Jun-Feng Qu, Mengchi Liu, Chunsheng Xin, Zhongbo Wu

Electrical & Computer Engineering Faculty Publications

High utility itemsets (HUIs) are sets of items with high utility, like profit, in a database. Efficient mining of high utility itemsets is an important problem in the data mining area. Many mining algorithms adopt a two-phase framework. They first generate a set of candidate itemsets by roughly overestimating the utilities of all itemsets in a database, and subsequently compute the exact utility of each candidate to identify HUIs. Therefore, the major costs in these algorithms come from candidate generation and utility computation. Previous works mainly focus on how to reduce the number of candidates, without dedicating much attention to …

Multidisciplinary Design Optimization Of Flexible Solar-Regenerative High-Altitude Long-Endurance Aircraft, Taylor Mcdonnell, Judd Mehr, Andrew Ning

Faculty Publications

Solar-Regenerative High-Altitude Long-Endurance (SR-HALE) aircraft are designed to sustain year-round flight at high altitudes indefinitely. No SR-HALE aircraft has yet accomplished this task due to the complex network of environmental, solar, structural, and aerodynamic trade-offs, among which aircraft flexibility plays a key role. A comprehensive SR-HALE aircraft multidisciplinary design optimization framework is developed in which the flexible aircraft analysis tool ASWING is incorporated in order to constrain nonlinear aeroelasticity. Energy, battery, ply thickness, material failure, local buckling, aerodynamic stall, longitudinal stability, and general stability (including flutter) constraints are applied in order to reasonably constrain the optimized SR-HALE aircraft design. An …