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2019

Electronic Theses and Dissertations

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Full-Text Articles in Engineering

Development Of An Electrical Interface For A Lateral Field Excited Sensor System, Thomas J. Leighton Aug 2019

Development Of An Electrical Interface For A Lateral Field Excited Sensor System, Thomas J. Leighton

Electronic Theses and Dissertations

Sensor systems are utilized to provide critical information to an end user which may range from a physician in a heath care facility to a soldier in a battle field environment. The "heart" of the sensor system is the sensing platform, examples of which include semiconductor, piezoelectric and optical devices. The responses of these sensors must be converted into a format that the user can read and interpret. This conversion is achieved through integrating the sensing platform with an electrical interface.

The focus of this thesis is the development of the first electrical interface for Quartz Crystal Microbalance (QCM) sensors ...


Triple-Junction Solar Cells : In Parallel., Levi C Mays Aug 2019

Triple-Junction Solar Cells : In Parallel., Levi C Mays

Electronic Theses and Dissertations

This paper looks into the current inefficiency of solar cells and attempts a few alternative solar cell structures in order to provide a more effective source of renewable energy. Currently, multi-junction solar cells are being developed to capture the sun’s light more efficiently. One of the ideas in this paper is to add a window to see if the addition of such a layer into a junction will increase the voltage while maintaining nearly the same current output. Central to this paper is the rearranging of the conducting layers of the multi-junction cell so that the junctions can be ...


Fluid Flow Analysis Of Diluted Evaporating American Whiskey Droplets., Martin J. Brown Vi Aug 2019

Fluid Flow Analysis Of Diluted Evaporating American Whiskey Droplets., Martin J. Brown Vi

Electronic Theses and Dissertations

The recent discovery of the unique structures, whiskey webs, formed when the evaporation of diluted American whiskey, has raised many questions as to the nature of the structures. Their formation process follows as such: (1) dilution of the whiskey to form nanoaggregates, (2) formation of a monolayer at the air-liquid interface, (3) chaotic ethanol evaporation caused monolayer collapse (via dynamic pressure), (4) bulk fluid evaporation caused monolayer collapse (via reduction of surface area), where the web-like structures reside on the surface, and finally, (5) web-like structures deposit on the substrate. The webs imaged via SEM had a striking resemblance to ...


Simulation Of A Continuum Tumor Model Using Distributed Computing., Dylan A Goodin Jul 2019

Simulation Of A Continuum Tumor Model Using Distributed Computing., Dylan A Goodin

Electronic Theses and Dissertations

Mathematical modeling aims to provide a theoretical framework for understanding tissue dynamics and for establishing treatment response for diseased tissues, such as tumors. Previously published continuum models have successfully represented idealized two-dimensional and three-dimensional tissue for short periods of time. A recently published continuum model of cancer increases model complexity and describes three-dimensional tissue that, due to the required complexity of the geometric multigrid solver, can only be feasibly applied to millimeter-scale simulations. Furthermore, the computational cost for such models has hindered their application in the laboratory and in the clinic. With computational demands greatly outpacing current openMP-based approaches on ...


Feasibility Study Of Intelligent Lvad Control For Optimal Heart Failure Therapy., John A. Karlen Iii Jul 2019

Feasibility Study Of Intelligent Lvad Control For Optimal Heart Failure Therapy., John A. Karlen Iii

Electronic Theses and Dissertations

Background: Left ventricular assist devices (LVAD) are operated at constant speeds (rpm), consequently, pump flow is passively determined by the pressure difference between the LV and aorta. Since the diastolic pressure gradient (~70 mmHg) is much larger than the systolic gradient (~10 mmHg), the majority of pump flow occurs during systole. This limitation results in sub-optimal LV volume unloading, LV washing, and diminished vascular pulsatility that may be associated with increased risk for clinically-significant adverse events, including stroke, bleeding, arteriovenous malformations, and aortic insufficiency. To address these clinical adverse events, an intelligent control strategy using pump speed modulation was developed ...


Prediction Of Paper Coating Mechanical Behavior Based On Particle-Scale Models, Daniel H. Varney May 2019

Prediction Of Paper Coating Mechanical Behavior Based On Particle-Scale Models, Daniel H. Varney

Electronic Theses and Dissertations

The mechanical properties of pigmented coatings are important for a number of situations; including coated paper, architectural paints, and structures in flexible lithium ion batteries. Coated paper and board undergo a variety of post coating application processes which have the potential to cause serious quality problems such as cracking, picking, and crack-at-the fold (CAF). Because a large number of parameters are known to influence the results, fundamental models are needed to help describe these processes and link them to the coating formulations and to the defects.

A discrete element method (DEM) computer model was developed to describe the pigment level ...


Investigating The Time-Dependent And The Mechanical Behavior Of Wood Plastic Composite Lumber Made From Thermally Modified Wood In The Use Of Marine Aquacultural Structures, Murtada A. Alrubaie May 2019

Investigating The Time-Dependent And The Mechanical Behavior Of Wood Plastic Composite Lumber Made From Thermally Modified Wood In The Use Of Marine Aquacultural Structures, Murtada A. Alrubaie

Electronic Theses and Dissertations

Wood Plastic Composite (WPC) lumber based on a patent-pending formulation is being explored for use in the manufacture of an aquaculture fish cage structure (Aquapod net pen cage), as an alternative to the current high density polyethylene (HDPE) lumber. The use of WPC lumber in structural applications in marine environments requires a comprehensive effort to understand the material viscoelastic behavior and the structural performance of the WPC lumber in marine environments where the WPC lumber is exposed to the combined effect of saltwater immersion and temperature (hygrothermal). The evaluation of the viscoelastic behavior of WPC lumber in marine environments was ...


Process Optimization Of Levulinic Acid Production From Seaweeds And Its Upgrading To Tdo Oil, Maurvin Patel May 2019

Process Optimization Of Levulinic Acid Production From Seaweeds And Its Upgrading To Tdo Oil, Maurvin Patel

Electronic Theses and Dissertations

Levulinic acid (LA) is a platform chemical and it can be upgraded to various products like bio-oil. The acid hydrolysis of cellulose is a widely researched pathway to make LA. However, investments to produce LA commercially can be subjected to risks due to feedstock price volatility and high processing costs. Such risks can be reduced by expanding the feedstock portfolio to produce LA from feedstock beyond wood and improving the energy efficiency of the process. One little investigated feedstock for production of LA is macro algae (seaweed). Seaweed is potentially attractive because it has low content of lignin or 5 ...


Tidal And Subtidal Processes At The Mouth Of A Macrotidal Estuary, Rachel Chambers May 2019

Tidal And Subtidal Processes At The Mouth Of A Macrotidal Estuary, Rachel Chambers

Electronic Theses and Dissertations

Secondary flows and mixing have been shown to influence sediment transport, the vertical salinity gradient, and the exchange flow in estuaries. Typically, these hydrodynamic properties are investigated with respect to time and depth and their variability across the estuary is neglected. However, recent studies have shown that secondary flows and mixing, along with mechanisms that influence them, can exhibit lateral variability. Additionally, the variability of these hydrodynamic properties has not been studied in macrotidal estuaries, where the increased tidal forcing could affect the strength and cross channel variability.

There are two primary objectives of this thesis. The first objective is ...


Perspectives On Water Resources Risk, Policy, And Stewardship, Anne Marie Lausier May 2019

Perspectives On Water Resources Risk, Policy, And Stewardship, Anne Marie Lausier

Electronic Theses and Dissertations

Water management approaches have historically optimized water for human use and placed lower emphasis on the relationship between ecosystems and humans. Despite efforts to balance human and ecosystem needs, existing management approaches tend to prioritize some needs, knowledges, and values over others. Natural and anthropogenic changes pose challenges to water governance institutions due to policy inflexibility, and may lead to ecosystem degradation, water stress, and conflict among water users. This work seeks to redress these shortcomings through three scholarly contributions. First, a conceptual framework for Water Resources Stewardship is developed in support of equitable and adaptive solutions under changing conditions ...


Conversion Of Pretreated Hardwood To Medium-Chain Fatty Acids For Production Of Biolubricants, Koorosh Kashkooli May 2019

Conversion Of Pretreated Hardwood To Medium-Chain Fatty Acids For Production Of Biolubricants, Koorosh Kashkooli

Electronic Theses and Dissertations

Medium-chain fatty acids (MCFA, e.g., hexanoic, heptanoic and octanoic acid) are versatile chemical compounds that are suitable precursors for the production of high-carbon-number, value-added chemicals such as bio-based lubricants. Short-chain fatty acids (SCFA, e.g., acetic, propionic, butyric, valeric acid) and methane are the natural fermentation products of anaerobic digestion, however, they have a lower value compared to MCFAs. Our current investigation seeks to integrate the production of MCFAs through chain elongation fermentation of pretreated biomass with catalytic conversion of MCFAs to lubricant molecules. By adding reducing agents such as ethanol and lactic acid to the anaerobic digestion, and ...


Tide And Storm Surge Dynamics In Estuaries Of Variable Morphology, Preston Spicer May 2019

Tide And Storm Surge Dynamics In Estuaries Of Variable Morphology, Preston Spicer

Electronic Theses and Dissertations

Storm surges are the most destructive component of coastal storms, and climate change is predicted to enhance the frequency of intense storm events in the future. Currently, most storm surge forecasting assumes linear surges and the extent to which this assumption leads to model inaccuracies is currently unknown. The goals of this research are to characterize storm surge in estuaries and determine the contribution of nonlinear tide-surge interaction to total inland surges. A citizen science experiment was conducted in four estuaries in Maine. Results show the estuary shape influences surges through convergence, friction and man-made constrictions. These mechanisms modified total ...


Successful Factors For Native And Community College Transfer Students In Engineering Technology At A Four-Year University, Leendert Craig May 2019

Successful Factors For Native And Community College Transfer Students In Engineering Technology At A Four-Year University, Leendert Craig

Electronic Theses and Dissertations

Students who attend community colleges often transfer to 4-year universities seeking to earn a degree typically not offered at the community college level. Tennessee has 2 programs: the Tennessee Promise and the Tennessee Reconnect programs that offer students tuition-free access to the state’s community college system. Previous studies have been conducted to compare transfer students’ performances to that of native students and typically compared the students in all disciplines. This study seeks to compare transfer students (students who enter the participating university with 40 or more credit hours) to native students (students who initially enrolled or transferred into the ...


The Eco-Smart Can V2.0, Darack B. Nanto May 2019

The Eco-Smart Can V2.0, Darack B. Nanto

Electronic Theses and Dissertations

On a scorching summer day in 2015, a campus maintenance worker was observed emptying a trash bin. Upon closer observation, it was noted that the bin was not full; in fact, it was less than one third full. There were other bins that were full and needed to be emptied urgently. It was confusing and problematic to see that bins that needed more attention were not prioritized. After extended research, it was found that maintenance operates on daily routes to pick up trash at designated times, regardless of the level of trash in the bins. Therefore, to tackle this issue ...


Influence Of Mechanical Properties Of Paper Coating On The Crack At The Fold Problem, Seyyed Mohammad Hashemi Najafi May 2019

Influence Of Mechanical Properties Of Paper Coating On The Crack At The Fold Problem, Seyyed Mohammad Hashemi Najafi

Electronic Theses and Dissertations

Paper coating layers are subject to various stresses and deformations in many converting processes such as calendering, printing, slitting, and folding of the paper. In some cases, products may crack during folding to generate a defect called cracking at the fold (CAF). The parameters that influence these defects are not well understood. The overall goal of this thesis is to better understand the CAF behavior as related to material properties of the coating layer.

A method was developed to produce free-standing pigmented coating layers thick enough to be tested in bending as well as tension. The mechanical properties of these ...


Parameters That Influence The Performance Of Dispersion Barrier Coatings, Randy Raditya May 2019

Parameters That Influence The Performance Of Dispersion Barrier Coatings, Randy Raditya

Electronic Theses and Dissertations

Barrier coating layers are important in many paper grades used in food packaging and have the potential to help reduce our use of plastics in some situations. Barrier layers to produce water proof packaging such as milk or juice cartons or coffee cups are common. Water based dispersion barrier coatings have the potential to be a low-cost alternative to extrusion coated layers. Water borne coatings are reported to be easy to recycle and break down in the environment. However, barrier properties are often less than what is desired and expected for these water borne coatings. The reason for this poor ...


Modeling And Counteracting Exposure Bias In Recommender Systems., Sami Khenissi May 2019

Modeling And Counteracting Exposure Bias In Recommender Systems., Sami Khenissi

Electronic Theses and Dissertations

Recommender systems are becoming widely used in everyday life. They use machine learning algorithms which learn to predict our preferences and thus influence our choices among a staggering array of options online, such as movies, books, products, and even news articles. Thus what we discover and see online, and consequently our opinions and decisions, are becoming increasingly affected by automated predictions made by learning machines. Similarly, the predictive accuracy of these learning machines heavily depends on the feedback data, such as ratings and clicks, that we provide them. This mutual influence can lead to closed-loop interactions that may cause unknown ...


Automatic Signal And Image-Based Assessments Of Spinal Cord Injury And Treatments., Samineh Mesbah May 2019

Automatic Signal And Image-Based Assessments Of Spinal Cord Injury And Treatments., Samineh Mesbah

Electronic Theses and Dissertations

Spinal cord injury (SCI) is one of the most common sources of motor disabilities in humans that often deeply impact the quality of life in individuals with severe and chronic SCI. In this dissertation, we have developed advanced engineering tools to address three distinct problems that researchers, clinicians and patients are facing in SCI research. Particularly, we have proposed a fully automated stochastic framework to quantify the effects of SCI on muscle size and adipose tissue distribution in skeletal muscles by volumetric segmentation of 3-D MRI scans in individuals with chronic SCI as well as non-disabled individuals. We also developed ...


An Explainable Sequence-Based Deep Learning Predictor With Applications To Song Recommendation And Text Classification., Khalil Damak May 2019

An Explainable Sequence-Based Deep Learning Predictor With Applications To Song Recommendation And Text Classification., Khalil Damak

Electronic Theses and Dissertations

Streaming applications are now the predominant tools for listening to music. What makes the success of such software is the availability of songs and especially their ability to provide users with relevant personalized recommendations. State of the art music recommender systems mainly rely on either Matrix factorization-based collaborative filtering approaches or deep learning architectures. Deep learning models usually use metadata for content-based filtering or predict the next user interaction (listening to a song) using a memory-based deep learning structure that learns from temporal sequences of user actions. Despite advances in deep learning models for song recommendation systems, none has taken ...


Lithium Molybdate-Sulfur Battery., Ruchira Ravinath Dharmasena May 2019

Lithium Molybdate-Sulfur Battery., Ruchira Ravinath Dharmasena

Electronic Theses and Dissertations

Rechargeable energy storage systems play a vital role in today’s automobile industry with the emergence of electric vehicles (EVs). In order to meet the targets set by the department of energy (DOE), there is an immediate need of new battery chemistries with higher energy density than the current Li- ion technology. Lithium–sulfur (Li–S) batteries have attracted enormous attention in the energy-storage, due to their high specific energy density of 2600 Wh kg-1 and operational voltage of 2.0 V. Despite the promising electrochemical characteristics, Li-S batteries suffer from serious technical challenges such as dissolution of polysulfides ...


Nanowire Based Adsorbents/Catalysts For Co2 Capture And Utilization., Apolo Nambo May 2019

Nanowire Based Adsorbents/Catalysts For Co2 Capture And Utilization., Apolo Nambo

Electronic Theses and Dissertations

Even today, the major energy source is fossil fuels, which release CO2, a greenhouse gas that contributes to global warming. CO2 capture, storage (CCS) and/or utilization (CCU) technologies are two routes to mitigate this problem. Sorbents are being investigated in either temperature swing or pressure swing absorption approaches for carbon capture from flue gases. Solid sorbent based technology is a promising one but suffers from slow kinetics, low capacity and need for high temperatures. Thus, new sorbent materials that can have good CO2 sorption capacity, recyclability are sought. Similarly, one of the utilization approaches for CO ...


A Two-Stage Approach To Ridesharing Assignment And Auction In A Crowdsourcing Collaborative Transportation Platform., Peiyu Luo May 2019

A Two-Stage Approach To Ridesharing Assignment And Auction In A Crowdsourcing Collaborative Transportation Platform., Peiyu Luo

Electronic Theses and Dissertations

Collaborative transportation platforms have emerged as an innovative way for firms and individuals to meet their transportation needs through using services from external profit-seeking drivers. A number of collaborative transportation platforms (such as Uber, Lyft, and MyDHL) arise to facilitate such delivery requests in recent years. A particular collaborative transportation platform usually provides a two sided marketplace with one set of members (service seekers or passengers) posting tasks, and the another set of members (service providers or drivers) accepting on these tasks and providing services. As the collaborative transportation platform attracts more service seekers and providers, the number of open ...


Maximizing Space Utilization In Unit-Load Warehouses., Luis Felipe Cardona Olarte May 2019

Maximizing Space Utilization In Unit-Load Warehouses., Luis Felipe Cardona Olarte

Electronic Theses and Dissertations

In a unit-load warehouse, products are stored and retrieved in pallet quantities. Examples include retail distribution centers (DC), third-party DCs, and transshipment hubs in freight transportation. Expenses related to space are a significant component of the operational cost of unit-load warehouses; therefore, maximizing space utilization is important. Moreover, the continuing revolution of retail e-commerce is changing the role and design of modern distribution centers (Boysen et al., 2018). An important trend with serious implications for design is the desire of many distributors to locate DCs in or near metropolitan areas in order to support same-day service or better (Thuermer, 2018 ...


Point Cloud Technology For Analysis Of Existing Structures, Jacob Cano May 2019

Point Cloud Technology For Analysis Of Existing Structures, Jacob Cano

Electronic Theses and Dissertations

For this thesis, a study was completed on two different structures on the UCF Orlando campus through the use of both structural plans and point cloud technology. The results sought to understand the viability of point cloud technology as an accurate tool for the static and dynamic modal analysis of existing structures. For static analysis, a portion of the framing of Spectrum Stadium was rendered, modeled, analyzed and compared to a previous case study. The results emphasized how different users can render dissimilar member sizes and lengths due to human judgment on point cloud visuals. The study also found that ...


Vibration Reduction Of Mistuned Bladed Disks Via Piezoelectric-Based Resonance Frequency Detuning, Garrett Lopp May 2019

Vibration Reduction Of Mistuned Bladed Disks Via Piezoelectric-Based Resonance Frequency Detuning, Garrett Lopp

Electronic Theses and Dissertations

Recent trends in turbomachinery blade technology have led to increased use of monolithically constructed bladed disks (blisks). Although offering a wealth of performance benefits, this construction removes the blade-attachment interface present in the conventional design, thus unintentionally removing a source of friction-based damping needed to counteract large vibrations during resonance passages. This issue is further exacerbated in the presence of blade mistuning that arises from small imperfections from otherwise identical blades and are unavoidable as they originate from manufacturing tolerances and operational wear over the lifespan of the engine. Mistuning is known to induce vibration localization with large vibration amplitudes ...


Game-Theoretic Frameworks And Strategies For Defense Against Network Jamming And Collocation Attacks, Ahmed Hemida May 2019

Game-Theoretic Frameworks And Strategies For Defense Against Network Jamming And Collocation Attacks, Ahmed Hemida

Electronic Theses and Dissertations

Modern networks are becoming increasingly more complex, heterogeneous, and densely connected. While more diverse services are enabled to an ever-increasing number of users through ubiquitous networking and pervasive computing, several important challenges have emerged. For example, densely connected networks are prone to higher levels of interference, which makes them more vulnerable to jamming attacks. Also, the utilization of software-based protocols to perform routing, load balancing and power management functions in Software-Defined Networks gives rise to more vulnerabilities that could be exploited by malicious users and adversaries. Moreover, the increased reliance on cloud computing services due to a growing demand for ...


Student Perceptions And Persistence : Taking A Person-Centered Approach To Understand Undergraduate Engineering Retention., Brittany Flanery Crawford May 2019

Student Perceptions And Persistence : Taking A Person-Centered Approach To Understand Undergraduate Engineering Retention., Brittany Flanery Crawford

Electronic Theses and Dissertations

Many students are leaving their engineering programs as early as the first semester of their undergraduate studies. Although some of the factors related to engineering retention are largely academic, others are tied closely to students’ beliefs or perceptions. Student perceptions data are useful, but often overlooked by researchers who wish to take a person-centered approach to uncover profiles of student beliefs, both adaptive and maladaptive, when it comes to understanding engineering retention. The sample consisted of full-time undergraduate engineering students (N = 834) in the first semester of their undergraduate engineering programs. I used latent transition analysis (LTA) to examine the ...


Plasma Oxidation Of Liquid Precursors For Complex Metal Oxides., Babajide Patrick Ajayi May 2019

Plasma Oxidation Of Liquid Precursors For Complex Metal Oxides., Babajide Patrick Ajayi

Electronic Theses and Dissertations

Clean energy production and storage are two of the most significant challenges in the 21st century currently limited by the discovery and development of new and advanced materials. Complex oxides and alloys made using earth-abundant elements will play a crucial role in technology development moving forward, however, current preparation techniques are limited by their inability to produce complex oxides and alloys with precise composition control at fast timescales. A concept was proposed to produce mixed metal oxides with composition control through the oxidation of liquid precursors via plasma oxidation. It was hypothesized that the oxidation process can be completed ...


Plasma-Assisted Liquid Phase Epitaxy Of Gallium Nitride Using Molten Gallium., Daniel Felipe Jaramillo-Cabanzo May 2019

Plasma-Assisted Liquid Phase Epitaxy Of Gallium Nitride Using Molten Gallium., Daniel Felipe Jaramillo-Cabanzo

Electronic Theses and Dissertations

Next generation semiconductor materials such as Gallium Nitride (GaN) and Silicon Carbide (SiC) are rapidly replacing Silicon (Si) for high power and high frequency applications due to Si’s inherent limitations. Despite the advantages of GaN over SiC, adoption of GaN has been hindered due to the lack of a cost-effective bulk production technique. Thus, the inability to precure native substrates requires GaN-based architectures to be heteroepitaxially synthesized on non-native substrates, such as sapphire and even SiC. This research seeks to develop a cost effective and scalable method to produce low defect, bulk GaN encouraging the adoption of GaN based ...


Characterization Of Florida Landfills With Elevated Temperatures, Ryan Joslyn May 2019

Characterization Of Florida Landfills With Elevated Temperatures, Ryan Joslyn

Electronic Theses and Dissertations

The occurrence of elevated temperatures within landfills is a very challenging issue for landfill operators to detect and correct. Little is known regarding the causes of elevated temperatures (ETs) and the number of landfills currently operating under such conditions. Therefore, the goal of this research was to determine which landfills within Florida have been impacted by ETs, and to develop a more complete understanding of the factors that may lead to these landfills becoming elevated temperature landfills (ETLFs). Historical landfill gas wellhead data, waste deposition reports, and landfill site geometry were collected for 27 landfill cells through the FDEP OCULUS ...