Engineering Commons^™

Marine Mammal Tracks From Two-Hydrophone Acoustic Recordings Made With A Glider, Elizabeth T. Küsel, Tessa Munoz, Martin Siderius, David K. Mellinger, Sara L. Heimlich

Electrical and Computer Engineering Faculty Publications and Presentations

A multinational oceanographic and acoustic sea experiment was carried out in the summer of 2014 off the western coast of the island of Sardinia, Mediterranean Sea. During this experiment, an underwater glider fitted with two hydrophones was evaluated as a potential tool for marine mammal population density estimation studies. An acoustic recording system was also tested, comprising an inexpensive, off-the-shelf digital recorder installed inside the glider. Detection and classification of sounds produced by whales and dolphins, and sometimes tracking and localization, are inherent components of population density estimation from passive acoustics recordings. In this work we discuss the equipment used …

Real-Time Internal Temperature Estimation And Health Monitoring For Igbt Modules, Ze Wang

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

Field experiences have demonstrated that power semiconductor devices, such as insulated-gate bipolar transistors (IGBTs), are among the most fragile components of power electronic converters. Thermomechanical stresses produced by temperature variations during operational and environmental loads are the major causes of IGBT degradation. As the devices are often operated under complex working conditions, temperature variations and the associated damage are difficult to predict during the converter design stage. A promising approach—online health monitoring and prognosis for power semiconductor devices—that can avoid device failure and effectively schedule maintenance has attracted much interest.

This dissertation research focused on real-time accurate internal temperature estimation …

The Discrete Spring Transform: An Innovative Steganographic Attack, Aaron T. Sharp

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

Digital Steganography continues to evolve today, where steganographers are constantly discovering new methodologies to hide information effectively. Despite this, steganographic attacks, which seek to defeat these techniques, have continually lagged behind. The reason for this is simple: it is exceptionally difficult to defeat the unknown. Most attacks require prior knowledge or study of existing techniques in order to defeat them, and are often highly specific to certain cover media. These constraints are impractical and unrealistic to defeat steganography in modern communication networks. It follows, an effective steganographic attack must not require prior knowledge or study of techniques, and must be …

Cradg: A Chaotic Radg Security System, Salah Albermany, Maryam Nathim, Zahir Hussain

Research outputs 2014 to 2021

A high-performance ciphering algorithm is presented. The proposed method combines old school ciphering (Reaction Automata Direct Graph (RADG)) with chaotic systems to obtain higher level of security. Chaotic sequences are highly sensitive to any changes in their parameters, adding a higher level of security to the proposed approach, called CRADG.

Fiber Bragg Grating Sensors For Mainstream Industrial Processes, Gary Allwood, Graham Wild, Steven Hinkley

Research outputs 2014 to 2021

This paper reviews fiber Bragg grating sensing technology with respect to its use in mainstream industrial process applications. A review of the various types of sensors that have been developed for industries such as power generation, water treatment and services, mining, and the oil and gas sector has been performed. A market overview is reported as well as a discussion of some of the factors limiting their penetration into these markets. Furthermore, the author’s make recommendations for future work that would potentially provide significant opportunity for the advancement of fiber Bragg grating sensor networks in these mainstream industries.

Biometric Encryption System For Increased Security, Ranjith Jayapal

UNF Graduate Theses and Dissertations

Security is very important in present day life. In this highly-interconnected world, most of our daily activities are computer based, and the data transactions are protected by passwords. These passwords identify various entities such as bank accounts, mobile phones, etc. People might reuse the same password, or passwords related to an individual that can lead to attacks. Indeed, remembering several passwords can become a tedious task. Biometrics is a science that measures an individual’s physical characteristics in a unique way. Thus, biometrics serves as a method to replace the cumbersome use of complex passwords. Our research uses the features of …

Enhancing The Existing Microscopic Simulation Modeling Practice For Express Lane Facilities, Kelvin S. Machumu

UNF Graduate Theses and Dissertations

The implementation of managed lanes (MLs), also known as dynamically priced express lanes, to improve freeway traffic flow and personal throughput is on the rise. Congestion pricing is increasingly becoming a common strategy for congestion management, often requiring microscopic simulation during both planning and operational stages. VISSIM is a recognized microscopic simulation software used for analyzing the performance of managed lanes (MLs). This thesis addressed two important microscopic simulation issues that affect the evaluation results of MLs.

One of the microscopic simulation issues that has not yet been addressed by previous studies is the required minimum managed lane routing decision …

The Effect Of Corrosion Defects On The Failure Of Oil And Gas Transmission Pipelines: A Finite Element Modeling Study, Jennet Orasheva

UNF Graduate Theses and Dissertations

The transportation of oil and gas and their products through the pipelines is a safe and economically efficient way, when compared with other methods of transportation, such as tankers, railroad, trucks, etc. Although pipelines are usually well-designed, during construction and later in service, pipelines are subjected to a variety of risks. Eventually, some sections may experience corrosion which can affect the integrity of pipeline, which poses a risk in high-pressure operations. Specifically, in pipelines with long history of operation, the size and location of the corrosion defects need to be determined so that pressure levels can be kept at safe …

Segmental Movement Compensations In Patients With Transtibial Amputation Identified Using Angular Momentum Separation, Brecca M. M. Gaffney

Electronic Theses and Dissertations

Patients with unilateral dysvascular transtibial amputation (TTA) adopt movement compensations that are required to maintain balance and achieve ambulation in the absence of ankle plantar flexion, and result in increased and asymmetric joint loading patterns. As a result, this population is at an increased risk of overuse injuries, such as low back pain (LBP). Clinical gait analysis is used to guide diagnostics in movement retraining following amputation, and is performed using instrumented (research based) or observational analyses (clinically based). However, instrumented analyses are currently impractical in most clinical settings due to expense and computational limitations. This dissertation presents the use …

Promotional Effect Of Molten Carbonates On Proton Conductivity And Oxygen Reduction Reaction – An Experimental And Computational Study, Xiaolei Xiong

Theses and Dissertations

Recent research of Solid oxide fuel cells (SOFCs) is aimed to lower the operating temperature to an intermediate temperature (IT) range of 500 to 700^oC, while maintaining a proper performance. This Ph.D. research project investigates the promotional effects of alkaline carbonate eutectics on the proton conductivity of proton conducting electrolytes and cathodic ORR reactivity in SOFCs by both experimental and computational methods. The ionic conductivity of the MC-BZY composite above 500^oC increases with the higher loading of MC. The sample exhibited nearly a factor of two higher conductivity in H₂-containing atmosphere than in air. …

Carbon Nanomaterials And Their Application To Electrochemical Sensors: A Review, Aoife Power, Shaneel Chandra, Brian Gorey, James Chapman

Articles

Carbon has long been applied as an electrochemical sensing interface owing to its unique electrochemical properties. Moreover, recent advances in material design and synthesis, particularly nanomaterials, has produced robust electrochemical sensing systems that display superior analytical performance. Carbon nanotubes (CNTs) are one of the most extensively studied nanostructures because of their unique properties. In terms of electroanalysis, the ability of CNTs to augment the electrochemical reactivity of important biomolecules and promote electron transfer reactions of proteins is of particular interest. The remarkable sensitivity of CNTs to changes in surface conductivity due to the presence of adsorbates permits their application as …

An Enhanced Spring-Particle Model For Red Blood Cell Structural Mechanics: Application To The Stomatocyte–Discocyte– Echinocyte Transformation, Mingzhu Chen, Fergal Boyle

Articles

Red blood cells (RBCs) are the most abundant cellular element suspended in blood. Together with the usual biconcave-shaped RBCs, i.e., discocytes, unusual-shaped RBCs are also observed under physiological and experimental conditions, e.g., stomatocytes and echinocytes. Stomatocytes and echinocytes are formed from discocytes and in addition can revert back to being discocytes; this shape change is known as the stomatocyte–discocyte–echinocyte (SDE) transformation. To-date, limited research has been conducted on the numerical prediction of the full SDE transformation. Spring- particle RBC (SP-RBC) models are commonly used to numerically predict RBC mechanics and rheology. However, these models are incapable of predicting the full …

Precise Flow-Control Using Photo-Actuated Hydrogel Valves And Pid-Controlled Led Actuation, Colm Delaney, Simon Coleman, Jeff Whyte, Nigel Kent, Dermot Diamond

Articles

Herein we demonstrate remarkable control of flow within fluidic channels using photo-actuated hydrogel valves. By polymerizing the valves in situ it has been possible to create highly reproducible valves. Through the use of an LED platform and a PID algorithm we have generated extremely accurate flow control and created prototype devices to document their potential application within the microfluidics field.

3d Printing Aids Acetabular Reconstruction In Complex Revision Hip Arthroplasty, Andrew J. Hughes, Cathal Debuitleir, Philip Soden, Brian O'Donnchada, Anthony Tansey, Ali Abdulkarim, Colm Mcmahon, Conor J. Hurson

Articles

Revision hip arthroplasty requires comprehensive appreciation of abnormal bony anatomy. Advances in radiology and manufacturing technology have made three-dimensional (3D) representation of osseous anatomy obtainable, which provide visual and tactile feedback. Such life-size 3D models were manufactured from computed tomography scans of three hip joints in two patients. The first patient had undergone multiple previous hip arthroplasties for bilateral hip infections, resulting in right-sided pelvic discontinuity and a severe left-sided posterosuperior acetabular deficiency. The second patient had a first-stage revision for infection and recurrent dislocations. Specific metal reduction protocols were used to reduce artefact. The images were imported into Materialise …

Synthesis Of Difluoromethyl And Monofluoromethyl Ketones For Biological Evaluation At The Gaba-B Receptor, Mallory Maier

Honors Theses

The central nervous system communicates using neurotransmitters. Most are excitatory neurotransmitters, such as acetylcholine, dopamine, and serotonin, but

Robust And Agile System Against Fault And Anomaly Traffic In Software Defined Networks, Mihui Kim, Younghee Park, Rohit Kotalwar

Faculty Publications

The main advantage of software defined networking (SDN) is that it allows intelligent control and management of networking though programmability in real time. It enables efficient utilization of network resources through traffic engineering, and offers potential attack defense methods when abnormalities arise. However, previous studies have only identified individual solutions for respective problems, instead of finding a more global solution in real time that is capable of addressing multiple situations in network status. To cover diverse network conditions, this paper presents a comprehensive reactive system for simultaneously monitoring failures, anomalies, and attacks for high availability and reliability. We design three …

Analysis And Design Of A Highly Compact Ellipse-Shaped Ultra-Wideband Bandpass Filter (Uwb-Bpf) With A Notched Band, Xuetan Liu

Theses and Dissertations

Since the Federal Communications Commission’s endorsement of the frequency band of 3.1 – 10.6 GHz in 2002 to be unlicensed for wireless communication applications, various ultra-wideband bandpass filters (UWB-BPFs) have been proposed and designed. Different UWB-BPF configurations were presented in the past years to meet the very strict UWB-BPF specifications in terms of ultra-band requirement, low return loss, high rejection in notched bands. However, most of the previous works are limited by large dimension size, complex geometry, and high production cost.

The major objective of this work is to design a highly compact, simple geometry, and low-cost UWB-BPF, which passes …

Reducing Model Selection Computational Cost By Metamodeling The Evidence, Ramin Madarshahian

Theses and Dissertations

Modeling is an abstraction of reality that lets a designer or engineer perform simulations with a “real” object or structure without testing it physically. However, the result of simulations is as good as their models. Selecting the best model among many candidates is another challenge.

Complex models could translate into more accurate predictions, but they also require larger computational effort. The Bayes factor is often used to compare different models considering the data and analyst’s experience. To obtain the Bayes factor, the Bayesian model evidence is calculated; however, calculating the Bayesian model evidence of computationally expensive models is not a …

Distributed Optimization Method For Intelligent Control Of Dc Microgrids, Yuanyuan Fan

Theses and Dissertations

Most of the distributed energy resources, loads and energy storage systems in a DC microgrid are equipped with power electronic converters. With the integration of advanced power electronics devices, a microgrid is able to utilize a broader range of technologies in its design and operation. A key feature of power electronic converter based systems is the ability to direct energy flow within a system with their coordinated operation. A system level control is needed for coordination where converters execute reference points dictated by a system-level control in order to achieve system level goals. System goals can be expressed as a …

Nondestructive Evaluation And Health Monitoring Of Adhesively Bonded Composite Structures, William Walker Roth

Theses and Dissertations

As the growth of fiber reinforced composite materials continues in many industries, structural designers will have to look to new methods of joining components. In order to take full advantage of composite materials, such as increased stiffness, decreased weight, tailored material properties and increased fatigue life, mechanical fasteners will need to be replaced by adhesive bonding or welding, when possible. Mechanical fasteners require the drilling of holes, which damages the laminate and becomes the source of further fatigue damage. Also, an increase in laminate thickness or inclusion of other features is required for the material to withstand the bearing stress …

A Comprehensive Evaluation Of Hybrid Wetting Configurations On Dropwise Condensation, Karim Khazal Egab

Theses and Dissertations

The heat transfer during condensation on a surface depends on the pattern design of the surface, which can highly influence hydrophobic/hydrophilic wettability. In this study hybrid pattern designs were studied. The relationship between the droplet dynamic and the hybrid pattern design can alter the drainage rates, droplet departure frequencies, and the condensation heat transfer rates. Therefore, two series of hybrid patterned surfaces have been designed, developed, and tested during condensation of water vapor on horizontal copper tubes, and compared to complete dropwise and complete filmwise condensation samples. This is to investigate the design that provides the maximum improvement in the …

Determination And Validation Of High-Pressure Equilibrium Adsorption Isotherms Via A Volumetric System, Hind Jihad Kadhim Shabbani

Theses and Dissertations

Adsorption equilibrium isotherms for N2, CO2, and CH4 on zeolite 13X were investigated at three different temperatures (25.5, 50.5 and 75.5 ̊ C) and a pressure range of (0-6.89475) MPa for CH4 and N2 and in the range of (0-4.82633) MPa for CO2 using built in volumetric apparatus. The results were validated using with a volumetric system (ASAP) at the same temperatures and a pressure up to (160-110) KPa respectively. The experimental results were correlated using three process Langmuir (TPLM). The correlated isotherms were then used to calculate the isosteric heat of adsorption for the three gases on 13X. The …

Stilbenes: Therapeutic Interventions Targeting Amyloid Β Protein Aggregation In Alzheimer’S Disease, Yiying Wang

Theses and Dissertations

Alzheimer’s disease (AD) is the most common form of dementia and accounts for 60-80 % of all dementia cases. In the United States, AD is ranked as the 6th leading cause of death and it is the only one among the top 10 that cannot be prevented, treated or even slowed. All FDA approved drugs focus on attenuating the symptoms for a limited time by regulating neurotransmitters without any intervention with the underlying disease process. A major player in the initiation and development of this debilitating disorder is the misfolding and subsequent aggregating of amyloid-β (Aβ) peptide. This aggregation process …

Statistical Mechanics Of Lipid-Liquid Crystal Systems: From Fundamentals To Sensing Applications, Donya Ohadi Kabir Maghsudlu

Theses and Dissertations

Understanding the thermodynamics of small systems has a well-established history. The non-intuitive behavior of the intensive properties of small systems comprised of less than a few hundred particles has important implications in many areas of engineering and materials science. Nevertheless, many open questions about the thermophysical properties of systems not in the thermodynamic limit remain unanswered. In the first part of this work, we explore the consequences of the coupling of two small subsystems that together make up a larger isolated system through the use of statistical mechanics and molecular dynamics simulations of Lennard-Jones particles in two dimensions. The results …

Pollutant Formation In Oxy-Coal Combustion, Nujhat Choudhury

Theses and Dissertations

With the increasing levels of carbon dioxide (CO2) in the atmosphere, researchers are driven to seek cleaner combustion techniques to burn coal for power generation. Oxy-coal combustion is a promising technique to cut down CO2 emissions. This technology requires the introduction of a pure oxygen (O2) stream and a recycled flue gas stream into the boiler instead of air. Flue gas stream generated from the system will be low in volume and highly concentrated in CO2. Thus, the capture and sequestration process will be facilitated. But, one of the concerns of adopting this technology is the altered chemistry of pollutants …

Characterization Of Subgrade Resilient Modulus For Mepdg And The Effects On Pavement Rutting, Md Mostaqur Rahman

Theses and Dissertations

In 2008, the American Association of State Highway and Transportation Officials (AASHTO) released a modified pavement design method (i.e., the Mechanistic Empirical Pavement Design Guide (MEPDG)) based on Long Term Pavement Performance (LTPP) data from all over the United States. The MEPDG default design parameters developed from the LTPP database are expected to be significantly different than those for South Carolina material, traffic and weather conditions, thus the default design parameters may not be accurate for South Carolina. Therefore, the new pavement design method should be calibrated for South Carolina conditions by performing MEPDG local calibration.

Different input variables should …

Multi-Axis Multi-Material Fused Filament Fabrication With Continuous Fiber Reinforcement, Wout De Backer

Theses and Dissertations

Additive Manufacturing (AM) has become a well-recognized method of manufacturing and has steadily become more accessible as it allows designers to prototype ideas, products and structures unconceivable with subtractive manufacturing techniques for both consumer grade and industrial grade applications. Commonly used thermoplastics for 3D printing have properties that may not be sufficient to comply with the application’s certification requirements, or their performance is less than desirable for aerospace and other high performance applications. Additionally, additively manufactured parts have reduced mechanical properties in the build direction of the print, and are generally weaker than their equivalent injection-molded parts. Furthermore, Computer Aided …

Confluence Of Density Currents Produced By Lock-Exchange, Hassan Ismail

Theses and Dissertations

Density currents represent a broad classification of flows driven by the force of gravity acting on a fluid with variable density. With examples of density currents including turbidity currents, sand storms, salt wedges in tidal rivers, and oil spills, a great deal of attention has been previously given to understanding the underlying mechanisms of such flows and implications of those flows on fluid, species, and sediment transport. Although documented confluences occur naturally in terrestrial and submarine settings,little attention has been given to understanding the confluence of two density currents.

This study furthers the state of knowledge on density current confluences …

Integrating Nano-Patterned Ferromagnetic And Ferroelectric Materials For Smart Tunable Microwave Applications, Tengxing Wang

Theses and Dissertations

The wireless communication market has been ever-growing in the recent decades. Radios with high performance and capabilities to support wireless connections are increasingly demanded. Recent developments in wireless communications targeting ubiquitous connections have resulted in ever more complex system structures for supporting multiple frequency bands and standards. Reconfigurable and tunable RF/microwave technologies have the potential to significantly simplify the systems. The main objective of this dissertation is to develop tunable technologies and design concepts, and propose a new design methodology to implement dually electrically tunable microwave components by integrating both selectively patterned ferromagnetic and ferroelectric materials.

The first part of …

Performance Assessment Of Hsrm Concrete Ties Through Finite Element Model Simulations, Adam I. Zeitouni

Theses and Dissertations

Concrete ties have become a promising alternative to timber ties for freight lines with increased curvature, high annual traffic, and large axle loads. They are also widely adopted in passenger lines. High strength (HS) concrete is the material of choice in the fabrication of prestressed concrete railroad ties. The higher strength of the concrete is directly related to higher values of the Elastic Modulus, thus increasing the rigidity of the material. The combination of increased strength, rigidity, and the material brittleness may lead to the development of high amplitude stresses with high gradients, which appears to be a common underlying …