High Speed, Micron Precision Scanning Technology For 3d Printing Applications, Nicholas Emord

UNF Graduate Theses and Dissertations

Modern 3D printing technology is becoming a more viable option for use in industrial manufacturing. As the speed and precision of rapid prototyping technology improves, so too must the 3D scanning and verification technology. Current 3D scanning technology (such as CT Scanners) produce the resolution needed for micron precision inspection. However, the method lacks in speed. Some scans can be multiple gigabytes in size taking several minutes to acquire and process. Especially in high volume manufacturing of 3D printed parts, such delays prohibit the widespread adaptation of 3D scanning technology for quality control. The limiting factors of current technology boil …

Development Of A One-Way Coupled Diffraction/Trapped Air Model For Predicting Wave Loading On Bridge Superstructure Under Water Wave Attack, Christian Hillary Matemu

UNF Graduate Theses and Dissertations

In recent years, a number of researchers have applied various computational methods to study wind wave and tsunami forcing on bridge superstructure problems. Usually, these computational analyses rely upon application of computational fluid dynamic (CFD) codes. While CFD models may provide reasonable results, their disadvantage is that they tend to be computationally expensive. During this study, an alternative computational method was explored in which a previously-developed diffraction model was combined with a previously-developed trapped air model under worst-case wave loading conditions (i.e. when the water surface was at the same elevation as the bottom bridge chord elevation). The governing equations …

Power Mobility Sensor Data Collection Verified Through Standardized Pediatric Assessments, Ayshka Elise Rodriguez-Velez

UNF Graduate Theses and Dissertations

The collaboration between the School of Engineering and the Department of Physical Therapy at the University of North Florida has introduced the possibility of creating a new environment for pediatric physical therapy assessments. There are currently no methods for remotely monitoring children with impairments. However, with embedded sensor technology in the form of power mobility and accepted therapy assessment tools, remote monitoring can become a possibility. As a part of this work, a ride-on toy car was developed as a remote monitoring device and a case study with a child with a mobility impairment was used as a proof of …

Establishing Relationships Among Environmental Stressors, Host Immune Status, And Wasting Disease Susceptibility In The Dominant Seagrass Species Thalassia Testudinum, Paige Joy Duffin

UNF Graduate Theses and Dissertations

A growing body of evidence supports the observation that marine disease outbreaks, especially those caused by opportunistic pathogens, are increasing in frequency and severity. One genus of such pathogens, Labyrinthula, has been identified as the causative agent of seagrass wasting disease, an epidemic that has historically plagued seagrass beds around the world. It is suspected that pathogenicity is intimately linked to the ability of the host to initiate defense responses, but a lack of compelling evidence prevents any meaningful application of preliminary observations. This body of work investigated the roles of host genotype, host immune status, and environmental stressors …

Profile Analysis Of Mobile Application Security, Adetunji A. Olunuga

UNF Graduate Theses and Dissertations

ABSTRACT

This thesis conducts profile analysis on the mobile application security using peer-review articles that were published from 2010 to 2018. From the analysis, we will identify prolific authors, intuitions, and geographic regions as well as the topics addressed by the articles. The profile analysis will reveal most frequently used research methods, research approaches (quantitative, qualitative and mixed), and theories used to study the field. This thesis reveals that none of the researchers have made significant contributions to the field, and researches are not collaborating to solve their research problems. The profile analysis shows that surveys and experiments are the …

A Consideration Of Mason’S Ethical Framework: The Importance Of Papa Factors In The 21st Century: A Seven-Year Study, Katharine Creevey Brown

UNF Graduate Theses and Dissertations

Richard Mason proposed a social framework for addressing the major ethical issues of the information age in his pivotal 1986 article “Four Ethical Issues of the Information Age.” In 2006, Alan Peslak validated the framework by measuring the current attitudes of students, IT professionals, and university faculty and staff toward the four key issues proposed by Mason: privacy, accuracy, property, and accessibility (referred to as PAPA). This study continues this inquiry into the seven-year period after Peslak’s research. Previously collected data was analyzed for 312 university computing majors taking a senior-level ethics course where Mason was taught and discussed. Demographic …

Implementation Of Cache Attack On Real Information Centric Networking System, Faustina J. Anto Morais

UNF Graduate Theses and Dissertations

Network security is an ongoing major problem in today’s Internet world. Even though there have been simulation studies related to denial of service and cache attacks, studies of attacks on real networks are still lacking in the research. In this thesis, the effects of cache attacks in real information-centric networking systems were investigated. Cache attacks were implemented in real networks with different cache sizes and with Least Recently Used, Random and First In First Out algorithms to fill the caches in each node. The attacker hits the cache with unpopular content, making the user request that the results be fetched …

Potential Replacement Of The Us Navy's Rapid Penetration Test With The Method Of Multichannel Analysis Of Surface Waves, William Fletcher

UNF Graduate Theses and Dissertations

The United States Navy (USN) currently utilizes a Rapid Penetration Test (RPT) on both land and in water as the means to determine whether sufficient soil bearing capacity exists for piles in axial compression, prior to construction of the Elevated Causeway System (Modular) [ELCAS(M)] pile-supported pier system. The USN desires a replacement for the RPT because of issues with the method incorrectly classifying soils as well as the need to have a less labor-and-equipment-intensive method for geotechnical investigation.

The Multichannel Analysis of Surface Waves (MASW) method is selected herein as the potential replacement for the RPT. The MASW method is …

Soil Improvement Using Microbial Induced Calcite Precipitation And Surfactant Induced Soil Strengthening, Matthew P. Davies

UNF Graduate Theses and Dissertations

Microbially induced calcite precipitation (MICP) has been used for a number of years as a technique for the improvement of various geological materials. MICP has been used in a limited capacity in organic rich soils with varying degrees of success. Investigators hypothesized that microbially-induced cementation could be improved in organic soils by using a surfactant. Varying amounts of Sodium Dodecyl Sulfate (SDS) were added to soils of varying organic content and a mixing procedure was used to treat these soils via MICP. Treated specimens were tested for unconfined compressive strength (UCS). Results appeared to show direct relationships between SDS content …

A Novel Design To Harness Water-Wave Energy, Abdallah El Safty, Abdallah Walid El Safty

UNF Graduate Theses and Dissertations

Renewable energy sources are essential to our future, not only because they generally minimize harm to our environment but are also a relatively free source of energy that are available for generations to come. Wind and solar energy are proven sources of renewable energy, but both are highly variable. On the other hand, water wave energy is relatively persistent in locations around the world. Many researchers have tried to capture the energy of ocean waves, some were successful, but most were not. Harnessing wave energy is not a simple matter. One must design systems that can withstand the extreme forces …

The Microstructural Annealing Response Of Cold Gas Dynamically Sprayed Al 6061, Clayton Andrew Cushway

UNF Graduate Theses and Dissertations

The Cold-Gas Dynamic-Spray process also known as Cold Spray (CS) has been researched for three decades. The CS process is a solid-state deposition technique via supersonic velocity of powder particles at a temperature significantly below the melting point of the spray material. This thesis presents background on the overall CS process parameters, and additional information on the microstructural and mechanical properties of typical Cold Sprayed materials.This Thesis primarily presents a study on the microstructural annealing response of CS Al 6061. It should be noted that for this study, the term “annealing” is used in the sense of the classical metallurgical …

Coupling Radio Frequency Energy Via The Embedded Rebar Cage In A Reinforced Concrete Structure For The Purpose Of Concrete Degradation Sensing, Ryan Campiz

UNF Graduate Theses and Dissertations

This study focuses on utilizing an energy harvesting system in which a dedicated Radio Frequency (RF) power source transmits RF power via rebar in a reinforced concrete column. The RF power is received and decoupled by a receiver, and is then rectified, boosted, and stored as electrical energy in a supercapacitor, later to be used to make measurements, process data, and communicate to the source via rebar. Two design attempts are presented in this study: (a) one uses single line conduction at 2.4 GHz for RF power transfer; (b) the other uses a more conventional two-line conduction at 8.0 kHz …

An Integrated Closed Convergent System For Optimal Extraction Of Head-Driven Tidal Energy, Michelle Ann Vieira

UNF Graduate Theses and Dissertations

As the demands for energy increased with the global increase in population, there is a need to create and invest in more clean and renewable energy sources. Energy derived from the movement of the tides is an ancient concept that is currently being harnessed in a handful of large tidal range locations. However, the need to move from fossil fuel driven energy sources to those that are clean and non-polluting is a priority for a sustainable future. Globally, hydropower potential is estimated to be more than 16,400-Terawatt hours annually. Given that the electricity consumption worldwide was at 15,068-Terawatt hours in …

Sensitivity Of Rheological Properties Of Cement Paste With Scc Consistency, Azadehalsadat A. Asghari

Doctoral Dissertations

"Robustness, which is defined as the capacity of a mixture to tolerate small variations in constituent elements, mixing parameters or temperature that are inevitable with production at any significant scale, is a key property to expand the practical implementation of self-consolidating concrete (SCC). At the first step, the effect of different amount of water, amount of superplastizer, mixing time, mixing speed and the addition time of superplastizer on the rheological properties of cement pastes with SCC consistency, has been evaluated. Two different SCC mix design concepts, the powder-type and VMA-type were selected for this research. The results show that the …

Modeling And Experimental Investigations On Particle Dynamic Behaviors In Laser 3d Printing With Blown Powder, Wei Li

Doctoral Dissertations

"Pre-mixed powder is frequently-used powder supply to fabricate Functional Gradient Material (FGM) by Laser 3D printing, which is also called Laser Metal Deposition (LMD). The deposited FGM composition is expected to be similar or same as supplied powder mixture. However, because pre-mixed powder has different particle densities and particle sizes, the caused particle acceleration differences can result in the separation in powder mixture. Up to now, there was no study focused on pre-mixed powders' flow behavior in LMD. The current research aims to investigate the flow behaviors of pre-mixed powder supplied for LMD through both experimental and modeling approaches. In …

Empirical Correlations Between Rock Cutting Parameters And Excavated Rock Surface Rebound Hardness, Azupuri Germanus Ayerikujei Kaba

Doctoral Dissertations

"In field excavation, cutting tools operate on rock surfaces damaged from previous tool pass, yet, average intact rock properties are often used in field project estimations. This can result in overestimation of excavation time and cost. The ability to accurately correlate the damaged rock properties to the excavation parameters means more reliable estimates of project completion time and costs, and hence improved the application of mechanical excavation technology to a wider range of civil and mining industries.

The purpose of this research was to better understand the relationship between rock cutting parameters and the excavated rock surface hardness during mechanical …

Correlation Between Delay Time And Measured Concentration And Concentration Uncertainty By Neutron Activation Analysis, James Thomas Seman

Doctoral Dissertations

"For the last several decades, it has been apparent that new methods of identifying explosives can help investigators trace their origins. One way to identify an explosive is through the use of taggants: materials added to a product that encodes information about the product such as when it was manufactured.

This research investigates the survivability of a new identification taggant called the Nuclear Barcode that overcomes some of the downfalls that have been identified in prior taggants. The Nuclear Barcode encodes information as a unique combination of concentrations of rare earths (Ho, Eu, Sm, Lu, and Dy) and precious metals …

Direct Numerical Simulation Of Pressure Fluctuations Induced By Supersonic Turbulent Boundary Layers, Chao Zhang

Doctoral Dissertations

"Direct Numerical Simulations are used to generate a database of high-speed zero-pressure-gradient turbulent boundary layers developing spatially over a flat plate with nominal freestream Mach number ranging from 2:5 to 14 and wall-to-recovery temperature ranging from 0:18 to 1:0. The flow conditions of the DNS are representative of the operational conditions of the Purdue Mach 6 quiet tunnel, the Sandia Hypersonic Wind Tunnel at Mach 8, and the AEDC Hypervelocity Tunnel No. 9 at Mach 14. The DNS database is used to gauge the performance of compressibility transformations, including the classical Morkovin's scaling and strong Reynolds analogy as well as …

Hydrodynamics Related Performance Evaluation Of Upflow Moving Bed Hydrotreater Reactor (Mbr) Using Developed Experimental Methods And Cfd Simulation, Vineet Alexander

Doctoral Dissertations

"Upflow Moving Bed Hydrotreater (MBR) reactor is used for hydrotreating resid crude oil. It is a two-phase upflow reactor having a catalyst bed with conical bottom, and plena. At industrial conditions the reactor is not performing at its best and encountering issues such as hot spots, catalyst agglomeration inside the catalyst bed leading to frequent shutdown of the reactor. The root cause of these problems are linked to the improper hydrodynamics inside the catalyst bed. To investigate this, the industrial scale MBR is scaled down to a pilot scale and indicative and key hydrodynamic parameters are investigated using developed experimental …

Torsional Behavior Of Rc Beams Strengthened With Pbo-Frcm Composite, Meyyada Y. Alabdulhady

Doctoral Dissertations

"Externally bonded fiber reinforced cementitious matrix (FRCM) composites have been investigated recently as an alternative to fiber reinforced polymer (FRP) composites to overcome certain shortcomings such as the inability to install on wet surfaces or in low temperatures, low fire resistance, low glass transition temperature, low reversibility, and lack of vapor permeability. This study includes an inclusive investigation of the torsional behavior of RC beams strengthened with externally bonded polyparaphenylene benzo-bisoxazole (PBO)-FRCM composite material. A comprehensive review and discussion of the previous experimental, analytical, and numerically-simulated torsional behavior of RC beams strengthened with FRP composite was introduced to gain a …

3d Seismic Attribute Analysis And Machine Learning For Reservoir Characterization In Taranaki Basin, New Zealand, Aamer Alhakeem

Doctoral Dissertations

"The Kapuni group within the Taranaki Basin in New Zealand is a potential petroleum reservoir. The objective of the study includes building a sequential approach to identify different geological features and facies sequences within the strata, through visualizing the targeted formations by interpreting and correlating the regional geological data, 3D seismic, and well data by following a sequential workflow. First, seismic interpretation is performed targeting the Kapuni group formations, mainly, the Mangahewa C-sand and Kaimiro D-sand. Synthetic seismograms and well ties are conducted for structural maps, horizon slices, isopach, and velocity maps. Well log and morphological analyses are performed for …

Process Simulation And Experimental Investigation Of Biofuel Production In A High Rate Anaerobic Digestion Process, Haider Al-Rubaye

Doctoral Dissertations

"The non-hazardous waste management hierarchy of the US EPA calls for “Reduce, Reuse, and Recycle” (or the three R’s) of wastes. The anaerobic digestion process is one of the most important methods that used to treat the wastes and at the same time generate energy out of it. The anaerobic digestion process generates a mixture of methane and carbon dioxide gases which is known as biogas.

The biogas composition is about 50-70% methane and 10-30% of carbon dioxide and trace amount of other gases like hydrogen and hydrogen sulfide. This biogas can be used in power generation, heating systems and …

Investigation Of The Hydrodynamics And Scale-Up Of Advanced Triso Nuclear Fuel Manufacturing Using Sophisticated Measurement Techniques, Thaar M. Aljuwaya

Doctoral Dissertations

"The successful performance and safety of the Very-High-Temperature Nuclear Reactors (VHTR) extremely depend on the quality of the TRISO nuclear fuel coated particles. However, the coating of the TRISO particles is delicate process and impacted by the hydrodynamics of spouted beds. Therefore, in this work, we applied advanced non-invasive measurement techniques which are gamma-ray computed tomography (CT) and radioactive particle tracking (RPT), to investigate foremost the local parameters to advance the fundamental understanding of the hydrodynamics and scale-up of gas-solid spouted beds. The CT technique has been applied to study the effects of particle density, particle size, bed size, and …

Imaging And Mitigating Karst Features, Kenneth Joseph Bansah

Doctoral Dissertations

"Over the last three years, a comprehensive subsurface investigation that combines both conventional and geophysical techniques has been conducted near Springfield in southwest Missouri, United States. This study, which forms part of the comprehensive subsurface investigation, aimed to (1) image and characterize the subsurface, (2) map variations in engineering properties of soil/rock, (3) map variable depth to top of rock, (4) explore the utility of the geophysical techniques, (5) determine the factors contributing to karst processes, and (6) propose karst mitigation. Electrical resistivity tomography (ERT) and multichannel analysis of surface waves (MASW) were employed for the acquisition of subsurface geophysical …

Gis-Based Spatial Analysis Coupled With Geophysical Imaging To Identify And Evaluate Factors That Control The Formation Of Karst Sinkholes In Southwestern Missouri, Shishay T. Kidanu

Doctoral Dissertations

"Sinkholes are inherent features of the karst terrain underlying much of Greene County, Missouri. These features present hazards and engineering challenges to existing infrastructure unknowingly constructed on a seemingly benign ground surface. The primary objective of this research was to investigate the physical processes chiefly responsible for triggering the seemingly random distribution of sinkholes in the study area. This research employed an integrated approach encompassing regional scale GIS-based spatial analyses and site-specific geophysical data. GIS-based spatial analysis was employed to identify significant physical factors that appeared to influence the formation and distribution of sinkholes. Seven out of the twelve most …

Guayule Plant Extracts As Binder Modifiers In Flexible (Asphalt) Pavement Mixtures, Steven Michael Lusher

Doctoral Dissertations

"The guayule (pronounced, 'why-YOO-lee') plant is a woody perennial shrub that is native to areas of the southwestern United States and northern Mexico, and is a well-documented source of high-quality natural rubber. The U.S. needs a domestic source of natural rubber to allay concerns about its future availability. Cultivation of guayule in North America has been attempted many times since the late 19th century, and companies, including major tire manufacturers, are again investing in guayule research. However, full-scale commercialization of guayule rubber needs established markets for the two basic by-products of guayule rubber extraction: the plant resins (primarily non-rubber compounds) …

A Multiple Scattering Method To Study The Cable Harness Inside A Vehicle Shell, Yansheng Wang

Doctoral Dissertations

"This dissertation contains three major parts. In the first part, a generalized multi-conductor transmission line (GMTL) method is proposed to model a cable harness. In the GMTL method, all wires of the cable harness take the infinity as the reference. In such a way, the GMTL method takes into account not only the transmission-line mode but also the antenna-mode current on the cable harness. Further, by employing the GMTL method and the mixed-potential integral equations (MPIE) method in a multiple scattering (MS) procedure, it enables an efficient and accurate approach to evaluate the current distribution on a cable harness with …

Learning-Based Short-Time Prediction Of Photovoltaic Resources For Pre-Emptive Excursion Cancellation, Huaiqi Xie

Doctoral Dissertations

"There is a growing interest in using renewable energy resources (RES) such as wind, solar, geothermal and biomass in power systems. The main incentives for using renewable energy resources include the growing interest in sustainable and clean generation as well as reduced fuel cost. However, the challenge with using wind and solar resources is their indeterminacy which leads to voltage and frequency excursions. In this dissertation, first, the economic dispatch (ED) problem for a community microgrid is studied which explores a community energy market. As a result of this work, the importance of modeling and predicting renewable resources is understood. …

Mining And Analysis Of Real-World Graphs, Armita Abedijaberi

Doctoral Dissertations

"Networked systems are everywhere - such as the Internet, social networks, biological networks, transportation networks, power grid networks, etc. They can be very large yet enormously complex. They can contain a lot of information, either open and transparent or under the cover and coded. Such real-world systems can be modeled using graphs and be mined and analyzed through the lens of network analysis. Network analysis can be applied in recognition of frequent patterns among the connected components in a large graph, such as social networks, where visual analysis is almost impossible. Frequent patterns illuminate statistically important subgraphs that are usually …

Development And Management Of Advanced Batteries Via Additive Manufacturing And Modeling, Jie Li

Doctoral Dissertations

"The applications of Li-ion batteries require higher energy and power densities, improved safety, and sophisticated battery management systems. To satisfy these demands, as battery performances depend on the network of constituent materials, it is necessary to optimize the electrode structure. Simultaneously, the states of the battery have to be accurately estimated and controlled to maintain a durable condition of the battery system. For those purposes, this research focused on the innovation of 3D electrode via additive manufacturing, and the development of fast and accurate physical based models to predict the battery status for control purposes. Paper I proposed a novel …