Engineering Commons^™

Effects Of Corrosion On The Sers Activity And Optical Response Of Silver Nanorods, Christopher J. Mealer

UNF Graduate Theses and Dissertations

The nanoscience and nanotechnology community have a common goal in better understanding the surfaced enhanced Raman scattering (SERS) that occurs due to laser plasmon resonance in conjunction with metal enhanced substrates. Metallic nanostructures, such as silver (Ag) nanorods, are widely used in biological and chemical sensing applications that rely on the measurement of subtle changes in the optical response of the nanostructures in the presence of a target agent. The optical response of Ag nanorods and most other metallic nanostructures is highly sensitive to morphology and surface chemical termination. In pristine condition, the optical properties of Ag nanorods and other …

Estimating A Range Of Flow Rates Resulting From Extreme Storm Events Within The Wekiva River Watershed Through Statistical Testing And Modeling, Wesley K. Koning

UNF Graduate Theses and Dissertations

The middle portion of the St. Johns River is located in East-Central Florida, USA. This region of the St. Johns River is increasingly subject to urbanization and conversion of forest areas to agricultural land. Overall, these changes mean that future flood events in the area could adversely impact local citizens. Therefore, the examination of extreme flood events and resiliency to such events is critical. The purpose of this preliminary study is to explore a range of practical applications to estimate extreme flood flows at watercourses within the Middle St. Johns River Basin, focusing specifically upon the Wekiva River sub-basin. The …

Linear Generators In Wave Energy Conversion: Performance, Feasibility, And Location Study, Luis Fernandez De Valderrama

UNF Graduate Theses and Dissertations

As the energy demand increases and climate change becomes a major problem, the solution to decrease greenhouse gas emissions and mitigate the effects of climate change involves increasing the use of sustainable and renewable sources to generate electricity. However, developed renewable sources have inconveniences that make them incapable of generating the totality of the electricity that a country demands. Wave energy is an alternative renewable energy source that can help mitigate the inconveniences of other renewable sources and decrease the emission of greenhouse gases.

This study aims to find the potential of linear generators in wave energy by analyzing the …

The Investigation Of The Underlying Microstructure Associated With Fracture Features In 6061 Cold Sprayed Aluminum, Justin White

UNF Graduate Theses and Dissertations

Cold gas dynamic spraying commonly known as cold spray is a process currently used for restoration, re-tolerancing, and application of coatings. With additional resources allocated towards the development of a through process model aimed at predicting the properties of bulk material produced via the Cold Spray process, more lab testing and investigation must be done to capture the effects of the varying microstructure in CS materials. The properties of ultra-fine-grained materials are derived from data collected from coarse grained materials and processes that do not accurately capture the effects as elevated strain rates and ultra-fine-grained materials. The lack of property …

Advance Metallic Reinforcement Of Vat Photo Polymerized Parts, Scott Zinn

UNF Graduate Theses and Dissertations

The metallization or metallic reinforcement of polymer parts has been widely used in industry for several decades. Polymer parts are classically metalized for aesthetics, chemical and thermal resistance, electrical conductivity, and mechanical strength. Metallization has been shown to increase strength of polymer parts when compared to the strength of the bulk material without metallization. Additive manufacturing (AM) techniques that have emerged in the last few decades produce parts with different surface features and chemistry than the typical polymer part produced through injection molding. AM parts are typically weaker than traditionally manufactured parts from the same material due to intrinsic details …

Exploring The Use Of Drones For Conducting Traffic Mobility And Safety Studies, Abdallah N. Kinero

UNF Graduate Theses and Dissertations

ABSTRACT

Advanced traffic data collection methods, including the application of aerial sensors (drones) as traffic data collectors, can provide real-time traffic information more efficiently, effectively, and safely than traditional methods. Traffic trajectory data like vehicles’ coordinates and point timestamps are challenging to obtain at intersections using traditional field survey methods. The coordinates and timestamps crucial in calculating trajectories can be obtained using drones and their particular integrated software. Thus, this study explores the use of unmanned aerial systems (UAS), particularly tethered drones, to obtain traffic parameters for traffic mobility and safety studies at an unsignalized intersection in Tallahassee, Florida. Tethered …

Energy Considerations In Blockchain-Enabled Applications, Cesar Enrique Castellon Escobar

UNF Graduate Theses and Dissertations

Blockchain-powered smart systems deployed in different industrial applications promise operational efficiencies and improved yields, while mitigating significant cybersecurity risks pertaining to the main application. Associated tradeoffs between availability and security arise at implementation, however, triggered by the additional resources (e.g., memory, computation) required by each blockchain-enabled host. This thesis applies an energy-reducing algorithmic engineering technique for Merkle Tree root and Proof of Work calculations, two principal elements of blockchain computations, as a means to preserve the promised security benefits but with less compromise to system availability. Using pyRAPL, a python library to measure computational energy, we experiment with both the …

Automatic Dependent Surveillance Broadcast (Ads-B) Security Mitigation Through Multilateration, Skylar Stroman

UNF Graduate Theses and Dissertations

Automatic Dependent Surveillance Broadcast (ADS-B) was mandated January 1^st, 2020 to all commercial aircraft that fly over 10,000 ft. This radio frequency (RF) based technology is part of an international plan to phase out radar-based surveillance within the airspace. Unfortunately, due to a lack of encryption and other security measures, ADS-B transmission remains open for possible exploitation. This thesis will explore the use of Multilateration (MLAT) to validate location data provided within the ADS-B framework. MLAT uses the Time Difference of Arrival (TDOA) at multiple locations to determine the origin of a received signal. Additionally, as MLAT greatly …

Analyzing Benefits Of Connected Vehicle Technologies During Incidents On Freeways And Diversion Strategies Implementation: A Microsimulation-Based Case Study Of Florida's Turnpike, Francisca P. Kasubi

UNF Graduate Theses and Dissertations

The full utilization of connected vehicles (CVs) is highly anticipated to become a reality soon. As CVs become increasingly prevalent in our roadway network, connected technologies have enormous potential to improve safety. This study conducted a microscopic simulation to quantify the benefits of CVs in improving freeway safety along a 7.8-mile section on Florida’s Turnpike (SR-91) system. The simulation incorporated driver compliance behavior in a CV environment. The simulation was implemented via an existing VISSIM network model partially developed by the Florida Department of Transportation (FDOT). In addition, the study analyzed how CVs would assist in detour operations as a …

Open Voting Client Architecture And Op-Ed Voting: A Novel Framework For Solving Requirement Conflicts In Secret Ballot Elections, Aaron M. Wilson

UNF Graduate Theses and Dissertations

Building voting systems for secret ballot elections has many challenges and is the subject of significant academic research efforts. These challenges come from conflicting requirements. In this paper, we introduce a novel architectural approach to voting system construction that may help satisfy conflicting requirements and increase voter satisfaction. Our design, called Open Voting Client Architecture, defines a voting system architectural approach that can harness the power of individualized voting clients. In this work, we contribute a voting system reference architecture to depict the current voting system construction and then use it to define Open Voting Client Architecture. We then detail …

Determination Of Extreme Flood Events In The Black Creek, Julington Creek, Dubin Creek, Big Davis Creek, Ortega River, And Pablo Creek Sub-Basins Of The Lower St. Johns River Basin, Florida, Usa, Samantha Kovalenko

UNF Graduate Theses and Dissertations

Extreme flood estimation is a continuously developing field of research. Economic and community well-being are dependent on flood risk preventative planning, which can only be successfully implemented through sound flood estimating methods. Without the execution of proper flood prevention measures, many communities remain at risk. In addition to a new extreme flood estimation methodology, this research presents a new approach to establish flood estimates. Traditionally, more than one flood estimate per return frequency storm does not exist. This research produced a set of 10-, 25-, 50-, and 100-year flood estimates for the Black Creek, Julington Creek, Durbin Creek, Big Davis …

Predicting Anthropogenic Underwater Pile Driving Noise Using Pile Driving Analyzer (Pda) Data, Brandon Alfredo Rivera

UNF Graduate Theses and Dissertations

In the past several years, there has been increasing concern about anthropogenic noise generated during marine pile driving. This concern is expected to increase concomitantly with increases in waterfront construction efforts associated with aging infrastructure and sea level rise. Several guidelines are available to help predict underwater noise transmission due to pile driving, but the issue with all these methods is that they require one to measure sound pressure levels at one locus or more from the driven pile. In the context of marine construction, adding specifications for underwater noise collection may be expensive or difficult because contractors typically have …

Macrotexture Assessment Of Florida Pavements, Alexander C. Oracheff

UNF Graduate Theses and Dissertations

When water has nowhere to escape from the surface of a roadway, it can disrupt the tire-to-pavement adhesion of a traveling vehicle and lead to hydroplaning. Pavement macrotexture provides the pathways for water to drain, which allows for the necessary grip between tire and pavement. Macrotexture, which is quantified by the Florida Department of Transportation (FDOT) in terms of mean profile depth (MPD), is analyzed by the State Materials Office using a high-speed point-laser mounted along the driver side wheel path of a friction testing vehicle.

While point-lasers are capable of accurately measuring MPD on flexible pavement, the system fails …

Modeling Coastal Vulnerability Of The St. Johns River And Northeastern Florida Shorelines, Madison E. Heppe

UNF Graduate Theses and Dissertations

Coastal and riverine communities, with anthropogenic congestion and natural and economic resources, are vulnerable to climate change impacts including rising sea levels and increasing severity and frequency of storms. Coastal habitats are being increasingly recognized as natural infrastructure that provides resiliency against these stressors. However, few studies have analyzed coastal vulnerability at landscape scale with finely resolved spatial data that account for habitats and demographics. The purpose of this study is to map the coastal vulnerability of the St. Johns River and adjacent Northeastern Florida Atlantic shoreline within the St. Johns River Water Management District. Unique to this study is …

A Microscopic Simulation Approach For Developing Ramp Metering Activation Guidelines For Weekends, Sarah T. Kasomi

UNF Graduate Theses and Dissertations

Traffic congestion is one of the major concerns in urban motorways. Agencies are implementing various Transportation Systems Management and Operations (TSM&O) strategies to reduce traffic congestion on roadway networks. Ramp metering is a TSM&O strategy that utilizes signals installed at freeways’ on-ramps to dynamically manage traffic entering the freeway. RMSs have been effective at alleviating recurring congestion. Recurring congestion, however, constitutes less than half of all congestion. More than half of all congestion is due to non-recurring events such as incidents, work zones, adverse weather conditions, special events, etc., that adversely affect the performance of a highway. Non-recurring congestion on …

Analysis Of Shallow Water Underwater Noise From Marine Pile Driving Using Computational Fluid Dynamics And Empirical Data Fitting, Moses Bosco

UNF Graduate Theses and Dissertations

There has been a growing concern in recent years about the effects of anthropogenic noise due to pile driving on underwater wildlife. Current guidelines for mitigating hydroacoustic effects associated with these geotechnical events are based upon a relatively simple transmission loss formulation known as the Practical Spreading Loss Model (PSLM). This model is easy to implement, but it may produce overly conservative results. Sound data during pile drives from several sites in Florida showed much higher sound attenuation than predicted by the PSLM. The first part of this study focused on explaining this discrepancy using computational fluid dynamics. Specifically, synthetic …

Safety Analysis Of Battery-Powered Adaptive Ride-On Toys For Children With Disabilities, Abbey Fraser

UNF Graduate Theses and Dissertations

Modified battery-powered ride-on toy cars, or adaptive ride-on toys, represent novel rehabilitation tools and developmental aids for children with disabilities. Studies have shown that children are benefiting socially and developmentally from their use. However, the use of these toys by children with disabilities potentially poses a risk of injury and it is vitally important to ensure the safe use of these toys, particularly for the benefit of those with developmental challenges.

Within this context, the purpose of the first study was to determine whether modifications to ride-on toys are sufficient to prevent common modes of injury such as falls, passenger …

Product Failure Recognition Via Comparison Of Sequential And Quickest Detection Algorithms, Christopher M. Beachler

UNF Graduate Theses and Dissertations

Under similar conditions, products that are designed and used for similar tasks fail similarly. Developers may become aware of various product failure modes during the initial stages of new product generation, where redesign and failure mitigation processes can occur with minimal detriment to consumer safety. Developers strive to mitigate the potential for catastrophic failures. This thesis concentrates on when these failures occur outside of controlled conditions, specifically where the development of processes feature low accuracy sensing techniques that impact the safety and operation of the end user. This thesis develops a set of statistical analysis simulation techniques using two existing …