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2015

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Theses/Dissertations

University of Central Florida

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Full-Text Articles in Physical Sciences and Mathematics

Terahertz Radiation From High-Temperature Superconducting Bscco Mesas Of Various Geometries, Daniel P. Cerkoney Dec 2015

Terahertz Radiation From High-Temperature Superconducting Bscco Mesas Of Various Geometries, Daniel P. Cerkoney

HIM 1990-2015

The purpose of this thesis is to examine the radiation from high-temperature superconducting mesas of Bi2Sr2CaCu2O8+ (BSCCO). This is motivated by the need for coherent sources of continuous wave terahertz (THz) emission capable of radiating practically in the THz frequency band. As BSCCO has been shown to be tunable from 0.5–2.4 THz (i.e., through the entire socalled terahertz gap centered about 1 THz), and has a higher peak operating temperature near 1 THz than most alternative sources, it is a good candidate for imaging and spectroscopy device applications [1]. When a static DC voltage is applied to a BSCCO mesa, …

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To Hydrate Or Chlorinate: A Regression Analysis Of The Levels Of Chlorine In The Public Water Supply, Drew A. Doyle Dec 2015

To Hydrate Or Chlorinate: A Regression Analysis Of The Levels Of Chlorine In The Public Water Supply, Drew A. Doyle

HIM 1990-2015

Public water supplies contain disease-causing microorganisms in the water or distribution ducts. In order to kill off these pathogens, a disinfectant, such as chlorine, is added to the water. Chlorine is the most widely used disinfectant in all U.S. water treatment facilities. Chlorine is known to be one of the most powerful disinfectants to restrict harmful pathogens from reaching the consumer. In the interest of obtaining a better understanding of what variables affect the levels of chlorine in the water, this thesis will analyze a particular set of water samples randomly collected from locations in Orange County, Florida. Thirty water …

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Angular Dependence Of The Emission From The Intrinsic Josephson Junction In Pie-Shaped Wedge Triangular Bscco Mesas, Manuel Morales May 2015

Angular Dependence Of The Emission From The Intrinsic Josephson Junction In Pie-Shaped Wedge Triangular Bscco Mesas, Manuel Morales

HIM 1990-2015

The purpose of this thesis is to determine the radiation patterns from an acute isosceles triangular superconducting mesa modeled by a pie-shaped geometry. The terahertz band lies between the microwave and infrared regions of the electromagnetic spectrum. The terahertz radiation from atomic-scale layered superconducting mesas is caused by the tunneling of electron pairs in the ac-Josephson effect. To determine the terahertz power radiated per unit solid angle of an acute isosceles triangular superconducting mesa, a model was employed in which the shape of the mesa is approximated as a pie-shaped wedge. This model is shown to have an accuracy of …

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Sparsification Of Social Networks Using Random Walks, Bryan Wilder May 2015

Sparsification Of Social Networks Using Random Walks, Bryan Wilder

HIM 1990-2015

Analysis of large network datasets has become increasingly important. Algorithms have been designed to find many kinds of structure, with numerous applications across the social and biological sciences. However, a tradeoff is always present between accuracy and scalability; otherwise promising techniques can be computationally infeasible when applied to networks with huge numbers of nodes and edges. One way of extending the reach of network analysis is to sparsify the graph by retaining only a subset of its edges. The reduced network could prove much more tractable. For this thesis, I propose a new sparsification algorithm that preserves the properties of …

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Broadband Coherent Perfect Absorption In One-Dimensional Optical Systems, Massimo Maximilian Villinger Jan 2015

Broadband Coherent Perfect Absorption In One-Dimensional Optical Systems, Massimo Maximilian Villinger

Electronic Theses and Dissertations

Absorption plays a critical role in a variety of optical applications – sometimes it is desirable to minimize it as in optical fibers and waveguides, or to enhance it as in solar cells and photodetectors. We describe here a new optical scheme that controllably produces high optical absorption over a broad wavelength range (hundreds of nm) in systems that have low intrinsic absorption over the same range. This effect, 'coherent perfect absorption' or CPA, arises from a subtle interplay between interference and absorption of two beams incident on a weakly absorbing medium. In the first part of this study, we …

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Synchrotron Based Infrared Microspectroscopy Of Carbonaceous Chondrites., Mehmet Yesiltas Jan 2015

Synchrotron Based Infrared Microspectroscopy Of Carbonaceous Chondrites., Mehmet Yesiltas

Electronic Theses and Dissertations

Relationships between organic molecules and inorganic minerals are investigated in five carbonaceous chondrites, Northwest Africa 852 (CR2), Tagish Lake (C2-ungroupped), Orgueil (CI1), Sutter's Mill (CM), and Murchison (CM2), with micron spatial resolution using synchrotron-based imaging micro-FTIR spectroscopy. Correlations based on absorption strength for various constituents are determined using statistical correlation analysis. Silicate band is found to be positively correlated with stretching modes of aliphatic hydrocarbons in NWA 852 and Tagish Lake. The former is highly correlated with the hydration band in all meteorites. Negative correlation is observed between water+organics and carbonate bands in all meteorites. Two dimensional infrared maps for …

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Reasoning Tradeoffs In Implicit Invocation And Aspect Oriented Languages, Jose Sanchez Salazar Jan 2015

Reasoning Tradeoffs In Implicit Invocation And Aspect Oriented Languages, Jose Sanchez Salazar

Electronic Theses and Dissertations

To reason about a program means to state or conclude, by logical means, some properties the program exhibits; like its correctness according to certain expected behavior. The continuous need for more ambitious, more complex, and more dependable software systems demands for better mechanisms to modularize them and reason about their correctness. The reasoning process is affected by the design decisions made by the developer of the program and by the features supported by the programming language used. Beyond Object Orientation, Implicit Invocation and Aspect Oriented languages pose very hard reasoning challenges. Important tradeoffs must be considered while reasoning about a …

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True Linearized Intensity Modulation For Photonic Analog To Digital Conversion Using An Injection-Locked Mode-Locked Laser, Edris Sarailou Jan 2015

True Linearized Intensity Modulation For Photonic Analog To Digital Conversion Using An Injection-Locked Mode-Locked Laser, Edris Sarailou

Electronic Theses and Dissertations

A true linearized interferometric intensity modulator for pulsed light has been proposed and experimentally presented in this thesis. This has been achieved by introducing a mode-locked laser into one of the arms of a Mach-Zehnder interferometer and injection-locking it to the input light (which is pulsed and periodic). By modulating the injection-locked laser, and combining its output light with the light from the other arm of interferometer in quadrature, one can achieve true linearized intensity modulator. This linearity comes from the arcsine phase response of the injection-locked mode-locked laser (as suggested by steady-state solution of Adler's equation) when it is …

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Improving Fairness, Throughput And Blocking Performance For Long Haul And Short Reach Optical Networks, Sana Tariq Jan 2015

Improving Fairness, Throughput And Blocking Performance For Long Haul And Short Reach Optical Networks, Sana Tariq

Electronic Theses and Dissertations

Innovations in optical communication are expected to transform the landscape of global communications, internet and datacenter networks. This dissertation investigates several important issues in optical communication such as fairness, throughput, blocking probability and differentiated quality of service (QoS). Novel algorithms and new approaches have been presented to improve the performance of optical circuit switching (OCS) and optical burst switching (OBS) for long haul, and datacenter networks. Extensive simulations tests have been conducted to evaluate the effectiveness of the proposed algorithms. These simulation tests were performed over a number of network topologies such as ring, mesh and U.S. Long-Haul, some high …

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Electronic Transport Properties Of Carbon Nanotubes: The Impact Of Atomic Charged Impurities, Ryuichi Tsuchikawa Jan 2015

Electronic Transport Properties Of Carbon Nanotubes: The Impact Of Atomic Charged Impurities, Ryuichi Tsuchikawa

Electronic Theses and Dissertations

Even changing one atom in nanoscale materials is expected to alter their properties due to their small physical sizes. Such sensitivity can be utilized to modify materials' properties from bottom up and is essential for the utility of nanoscale materials. As such, the impact of extrinsic atomic adsorbates was measured on pristine graphene and a network of carbon nanotubes using atomic hydrogen, cesium atoms, and dye molecules. In order to further quantify such an atomic influence, the resistance induced by a single potassium atom on metallic and semiconducting carbon nanotubes was measured for the first time. Carbon nanotubes are sensitive …

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Chemical Analysis, Databasing, And Statistical Analysis Of Smokeless Powders For Forensic Application, Dana-Marie Dennis Jan 2015

Chemical Analysis, Databasing, And Statistical Analysis Of Smokeless Powders For Forensic Application, Dana-Marie Dennis

Electronic Theses and Dissertations

Smokeless powders are a set of energetic materials, known as low explosives, which are typically utilized for reloading ammunition. There are three types which differ in their primary energetic materials; where single base powders contain nitrocellulose as their primary energetic material, double and triple base powders contain nitroglycerin in addition to nitrocellulose, and triple base powders also contain nitroguanidine. Additional organic compounds, while not proprietary to specific manufacturers, are added to the powders in varied ratios during the manufacturing process to optimize the ballistic performance of the powders. The additional compounds function as stabilizers, plasticizers, flash suppressants, deterrents, and opacifiers. …

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Liquid Crystal-Based Biosensors For The Detection Of Bile Acids, Sihui He Jan 2015

Liquid Crystal-Based Biosensors For The Detection Of Bile Acids, Sihui He

Electronic Theses and Dissertations

Bile acids are physiologically important metabolites, which are synthesized in liver as the end products of cholesterol metabolism and then secreted into intestine. They are amphiphilic molecules which play a critical role in the digestion and absorption of fats and fat-soluble vitamins through emulsification. The concentration of bile acids is an indicator for liver function. Individual suffering from liver diseases has a sharp increase in bile acid concentrations. Hence, the concentration level of bile acids has long been used as a biomarker for the early diagnosis of intestinal and liver diseases. Conventional methods of bile acid detection such as chromatography-mass …

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Propagation Failure In Discrete Inhomogeneous Medium Using A Caricature Of The Cubic, Elizabeth Lydon Jan 2015

Propagation Failure In Discrete Inhomogeneous Medium Using A Caricature Of The Cubic, Elizabeth Lydon

Electronic Theses and Dissertations

Spatially discrete Nagumo equations have widespread physical applications, including modeling electrical impulses traveling through a demyelinated axon, an environment typical in multiple scle- rosis. We construct steady-state, single front solutions by employing a piecewise linear reaction term. Using a combination of Jacobi-Operator theory and the Sherman-Morrison formula we de- rive exact solutions in the cases of homogeneous and inhomogeneous diffusion. Solutions exist only under certain conditions outlined in their construction. The range of parameter values that satisfy these conditions constitutes the interval of propagation failure, determining under what circumstances a front becomes pinned in the media. Our exact solutions represent …

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Selective Electro-Magnetic Absorbers Based On Metal-Dielectric-Metal Thin-Film Cavities, Janardan Nath Jan 2015

Selective Electro-Magnetic Absorbers Based On Metal-Dielectric-Metal Thin-Film Cavities, Janardan Nath

Electronic Theses and Dissertations

Efficient absorption of light is required for a large number of applications such as thermo-photovoltaics,thermal imaging, bio-sensing, thermal emitters, astronomy, and stealth technology. Strong light absorbers found in nature with high intrinsic losses such as carbon black, metal-black, and carbon nano-tubes etc. are bulky, not design-tunable and are hard to pattern for micro- and nano- devices. We developed thin-film, high performance absorbers in the visible, near-, mid-, long-wave - and far-IR region based on a 3 layer metal-dielectric-metal (MDM) structure. We fabricated a 3-layerMDMabsorber with large band-widths in the visible and near IR spectral range without any lithographic patterning. This …

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Functional Characterization Of Green Sorption Media And Scaling Of Pilot Studies For Copper Removal In Stormwater Runoff, Cameron Houmann Jan 2015

Functional Characterization Of Green Sorption Media And Scaling Of Pilot Studies For Copper Removal In Stormwater Runoff, Cameron Houmann

Electronic Theses and Dissertations

Green adsorption media with the inclusion of renewable and recycled materials can be applied as a stormwater best management practice for copper removal. A green adsorption media mixture composed of recycled tire chunk, expanded clay aggregate, and coconut coir was physicochemically evaluated for its potential use in an upflow media filter. The results found that the use of the green adsorption media mixture in isolation or the coconut coir with an expanded clay filtration chamber could be an effective and reliable stormwater best management practice for copper removal. A suite of tests were conducted on the media mixture and the …

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Synthesis Of Fluorene-Based Derivatives, Characterization Of Optical Properties And Their Applications In Two-Photon Fluorescence Imaging And Photocatalysis, Grace Githaiga Jan 2015

Synthesis Of Fluorene-Based Derivatives, Characterization Of Optical Properties And Their Applications In Two-Photon Fluorescence Imaging And Photocatalysis, Grace Githaiga

Electronic Theses and Dissertations

The two-photon absorption (2PA) phenomenon has attracted attention from various fields ranging from chemistry and biology to optics and engineering. Two of the common NLO applications in which organic materials have been used are three-dimensional (3D) fluorescence imaging and optical power limiting. Two-photon absorbing materials are, therefore, in great demand to meet the needs of emerging technologies. Organic molecules show great promise to meet this need as they can be customized through molecular engineering, and as the development of two-photon materials that suit practical application intensifies, so does research to meet this need. However, there remains some uncertainty in the …

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Fabrication And Study Of Graphene-Based Nanocomposites For Sensing And Energy Storage, Matthew Mcinnis Jan 2015

Fabrication And Study Of Graphene-Based Nanocomposites For Sensing And Energy Storage, Matthew Mcinnis

Electronic Theses and Dissertations

Graphite is an allotrope of carbon made up of atomically thin sheets, each covalently bound together, forming a π-conjugated network. An individual layer, called graphene, has extraordinary electrical, thermal and physical properties that provide the opportunity for innovating new functional composites. Graphene can be produced directly on a metallic substrate by chemical vapor deposition or by chemical oxidation of graphite, forming a stable aqueous suspension of graphene oxide (GO), which allows for convenient solution processing techniques. For the latter, after thermal or chemical reduction, much of the properties of the starting graphene re-emerge due to the reestablishment of π-conjugation. The …

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High Efficiency And Wide Color Gamut Liquid Crystal Displays, Zhenyue Luo Jan 2015

High Efficiency And Wide Color Gamut Liquid Crystal Displays, Zhenyue Luo

Electronic Theses and Dissertations

Liquid crystal display (LCD) has become ubiquitous and indispensable in our daily life. Recently, it faces strong competition from organic light emitting diode (OLED). In order to maintain a strong leader position, LCD camp has an urgent need to enrich the color performance and reduce the power consumption. This dissertation focuses on solving these two emerging and important challenges. In the first part of the dissertation we investigate the quantum dot (QD) technology to improve the both the color gamut and the light efficiency of LCD. QD emits saturated color and grants LCD the capability to reproduce color vivid images. …

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Electromechanical Lifting Actuation Of A Mems Cantilever And Nano-Scale Analysis Of Diffusion In Semiconductor Device Dielectrics, Imen Rezadad Jan 2015

Electromechanical Lifting Actuation Of A Mems Cantilever And Nano-Scale Analysis Of Diffusion In Semiconductor Device Dielectrics, Imen Rezadad

Electronic Theses and Dissertations

This dissertation presents experimental and theoretical studies of physical phenomena in micro- and nano-electronic devices. Firstly, a novel and unproven means of electromechanical actuation in a micro-electro-mechanical system (MEMS) cantilever was investigated. In nearly all MEMS devices, electric forces cause suspended components to move toward the substrate. I demonstrated a design with the unusual and potentially very useful property of having a suspended MEMS cantilever lift away from the substrate. The effect was observed by optical micro-videography, by electrical sensing, and it was quantified by optical interferometry. The results agree with predictions of analytic and numerical calculations. One potential application …

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Computerized Evaluatution Of Microsurgery Skills Training, Payal Jotwani Jan 2015

Computerized Evaluatution Of Microsurgery Skills Training, Payal Jotwani

Electronic Theses and Dissertations

The style of imparting medical training has evolved, over the years. The traditional methods of teaching and practicing basic surgical skills under apprenticeship model, no longer occupy the first place in modern technically demanding advanced surgical disciplines like neurosurgery. Furthermore, the legal and ethical concerns for patient safety as well as cost-effectiveness have forced neurosurgeons to master the necessary microsurgical techniques to accomplish desired results. This has lead to increased emphasis on assessment of clinical and surgical techniques of the neurosurgeons. However, the subjective assessment of microsurgical techniques like micro-suturing under the apprenticeship model cannot be completely unbiased. A few …

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Opportunistic Networks In Campus Environments, Salih Safa Bacanli Jan 2015

Opportunistic Networks In Campus Environments, Salih Safa Bacanli

Electronic Theses and Dissertations

Opportunistic communication is an active research area in wireless sensor networks. Exploiting the opportunities to communicate between devices in an unstable network is one of the main challenges of the opportunistic communication. In this thesis, we propose an infrastructure-independent opportunistic mobile social networking strategy for efficient message broadcasting in campus environments. Specifically, we focus on the application scenario of university campuses. In our model, the students' smartphones forward messages to each other. The messages are created spontaneously as independent events in various places of the campus. The events can be either urgent security alerts or private announcements to the students …

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Development Of A Nano-Sensing Approach And A Portable Prototype For Real-Time Detection And Quantification Of Free Mercury In Stream-Flow: Combining Science And Engineering In Pro Of The Environment, Warinya Chemnasiri Jan 2015

Development Of A Nano-Sensing Approach And A Portable Prototype For Real-Time Detection And Quantification Of Free Mercury In Stream-Flow: Combining Science And Engineering In Pro Of The Environment, Warinya Chemnasiri

Electronic Theses and Dissertations

Mercury (Hg) is a well-known hazardous environmental contaminant existing in several forms, but all are toxic to human in one way or the others. Since Hg usually settles into water polluting the environment and accumulating in living organisms, it is crucial to monitor Hg levels in the aquatic ecosystem. Although there are many well established techniques currently used to detect Hg, most of them require elaborate and time-consuming sample preparation and pre-concentration procedures, as well as costly and bulky equipment that limit their practical application in the field. In order to overcome the existent limitations in Hg determination methods, Hernandez …

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Entanglement And Coherence In Classical And Quantum Optics, Kumel Kagalwala Jan 2015

Entanglement And Coherence In Classical And Quantum Optics, Kumel Kagalwala

Electronic Theses and Dissertations

We explore the concepts of coherence and entanglement as they apply to both the classical and quantum natures of light. In the classical domain, we take inspiration from the tools and concepts developed in foundational quantum mechanics and quantum information science to gain a better understanding of classical coherence theory of light with multiple degrees of freedom (DoFs). First, we use polarization and spatial parity DoFs to demonstrate the notion of classical entanglement, and show that Bell's measure can serve as a useful tool in distinguishing between classical optical coherence theory. Second, we establish a methodical yet versatile approach called …

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A Simulation-Based Task Analysis Using Agent-Based, Discrete Event And System Dynamics Simulation, Anastasia Angelopoulou Jan 2015

A Simulation-Based Task Analysis Using Agent-Based, Discrete Event And System Dynamics Simulation, Anastasia Angelopoulou

Electronic Theses and Dissertations

Recent advances in technology have increased the need for using simulation models to analyze tasks and obtain human performance data. A variety of task analysis approaches and tools have been proposed and developed over the years. Over 100 task analysis methods have been reported in the literature. However, most of the developed methods and tools allow for representation of the static aspects of the tasks performed by expert system-driven human operators, neglecting aspects of the work environment, i.e. physical layout, and dynamic aspects of the task. The use of simulation can help face the new challenges in the field of …

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Attosecond Transient Absorption Spectroscopy Of Atoms And Molecules, Yan Cheng Jan 2015

Attosecond Transient Absorption Spectroscopy Of Atoms And Molecules, Yan Cheng

Electronic Theses and Dissertations

One of the most fundamental goals of attosecond science is to observe and to control the dynamic evolutions of electrons in matter. The attosecond transient absorption spectroscopy is a powerful tool to utilize attosecond pulse to measure electron dynamics in quantum systems directly. In this work, isolated single attosecond pulses are used to probe electron dynamics in atoms and to study dynamics in hydrogen molecules using the attosecond transient absorption spectroscopy technique. The target atom/molecule is first pumped to excited states and then probed by a subsequent attosecond extreme ultraviolet (XUV) pulse or by a near infrared (NIR) laser pulse. …

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Theoretical And Computational Studies Of The Electronic, Structural, Vibrational, And Thermodynamic Properties Of Transition Metal Nanoparticles, Ghazal Shafai Erfani Jan 2015

Theoretical And Computational Studies Of The Electronic, Structural, Vibrational, And Thermodynamic Properties Of Transition Metal Nanoparticles, Ghazal Shafai Erfani

Electronic Theses and Dissertations

The main objective of this dissertation is to provide better understanding of the atomic configurations, electronic structure, vibrational properties, and thermodynamics of transition metal nanoparticles and evaluate the intrinsic (i.e. size and shape) and extrinsic (i.e. ligands, adsorbates, and support) effects on the aforementioned properties through a simulational approach. The presented research provides insight into better understanding of the morphological changes of the nanoparticles that are brought about by the intrinsic factors as well as the extrinsic ones. The preference of certain ligands to stabilize specific sizes of nanoparticles is investigated. The intrinsic and extrinsic effects on the electronic structure …

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Modeling Network Worm Outbreaks, Evan Foley Jan 2015

Modeling Network Worm Outbreaks, Evan Foley

Electronic Theses and Dissertations

Due to their convenience, computers have become a standard in society and therefore, need the utmost care. It is convenient and useful to model the behavior of digital virus outbreaks that occur, globally or locally. Compartmental models will be used to analyze the mannerisms and behaviors of computer malware. This paper will focus on a computer worm, a type of malware, spread within a business network. A mathematical model is proposed consisting of four compartments labeled as Susceptible, Infectious, Treatment, and Antidotal. We shall show that allocating resources into treating infectious computers leads to a reduced peak of infections across …

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Conservation Laws And Electromagnetic Interactions, Veerachart Kajorndejnukul Jan 2015

Conservation Laws And Electromagnetic Interactions, Veerachart Kajorndejnukul

Electronic Theses and Dissertations

Aside from energy, light carries linear and angular momenta that can be transferred to matter. The interaction between light and matter is governed by conservation laws that can manifest themselves as mechanical effects acting on both matter and light waves. This interaction permits remote, precise, and noninvasive manipulation and sensing at microscopic levels. In this dissertation, we demonstrated for the first time a complete set of opto-mechanical effects that are based on nonconservative forces and act at the interface between dielectric media. Without structuring the light field, forward action is provided by the conventional radiation pressure while a backward movement …

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The Safe Removal Of Frozen Air From The Annulus Of A Liquid Hydrogen Storage Tank, Angela Krenn Jan 2015

The Safe Removal Of Frozen Air From The Annulus Of A Liquid Hydrogen Storage Tank, Angela Krenn

Electronic Theses and Dissertations

Large Liquid Hydrogen (LH2) storage tanks are vital infrastructure for NASA. Eventually, air may leak into the evacuated and perlite filled annular region of these tanks. Although the vacuum level is monitored in this region, the extremely cold temperature causes all but the helium and neon constituents of air to freeze. A small, often unnoticeable pressure rise is the result. As the leak persists, the quantity of frozen air increases, as does the thermal conductivity of the insulation system. Consequently, a notable increase in commodity boiloff is often the first indicator of an air leak. Severe damage can then result …

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Nanoscale Control Of Gap-Plasmon Enhanced Optical Processes, Chatdanai Lumdee Jan 2015

Nanoscale Control Of Gap-Plasmon Enhanced Optical Processes, Chatdanai Lumdee

Electronic Theses and Dissertations

Surface plasmon resonances of metal nanostructures have been studied intensely in recent years. The strong plasmon-mediated electric field enhancement and field confinement well beyond the diffraction limit has been demonstrated to improve the performance of optical devices including ultrasensitive sensors, light emitters, and optical absorbers. A plasmon resonance mode of particular recent interest is the gap plasmon resonance that occurs on closely spaced metallic structures. In contrast to plasmon resonances supported by isolated metal nanostructures, coupled nanostructures provide additional spectral and spatial control over the plasmon resonance response. For example, the resonance frequencies of metal nanoparticle dimers depend strongly on …

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