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Articles 31 - 60 of 68
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The Effectiveness Of Teaching Methods Designed To Improve Student Engagement And Retention Of Physics Subject Matter For Both Science And Non-Science Majors, Dan Maronde
Electronic Theses and Dissertations
The necessity of students’ engagement with the subject matter for successful learning is welldocumented in education research in general, and in physics education research in particular. This study examines the merits of two different programs designed to improve student learning through enhanced student engagement with the material. The target populations of the two programs are different: One is the group of students taking a physical science class as part of the general curriculum required of non-science, non-engineering majors; the other is the group of students, mostly in engineering disciplines, who must take the calculus-based introductory physics sequence as part of …
Two-Photon Cross Section Enhancement Of Photochromic Compounds For Use In 3d Optical Data Storage, Gheorghe Luchita
Two-Photon Cross Section Enhancement Of Photochromic Compounds For Use In 3d Optical Data Storage, Gheorghe Luchita
Electronic Theses and Dissertations
Rewritable photochrome-based 3D optical data storage requires photochromic molecules with high two-photon absorption (2PA) cross sections. Currently, the low value of two-photon absorption cross sections of existing photochromes makes them unsuitable for practical application in 3D data storage. Worldwide attempts to increase the cross section of photochromic molecules by altering the chemical structure have yielded poor results. In this work, two ways to increase the two-photon absorption cross sections of photochromes were investigated. In the first method, partial success demonstrated by extending the conjugation of a photochromic molecule, a high two-photon absorption cross section of the closed form isomer and …
Algebraic Aspects Of (Bio) Nano-Chemical Reaction Networks And Bifurcations In Various Dynamical Systems, Teng Chen
Electronic Theses and Dissertations
The dynamics of (bio) chemical reaction networks have been studied by different methods. Among these methods, the chemical reaction network theory has been proven to successfully predicate important qualitative properties, such as the existence of the steady state and the asymptotic behavior of the steady state. However, a constructive approach to the steady state locus has not been presented. In this thesis, with the help of toric geometry, we propose a generic strategy towards this question. This theory is applied to (bio)nano particle configurations. We also investigate Hopf bifurcation surfaces of various dynamical systems.
Self-Assembly Of Squaraine Dyes, Maher A. Qaddoura
Self-Assembly Of Squaraine Dyes, Maher A. Qaddoura
Electronic Theses and Dissertations
Squaraine dyes have been a subject of extensive investigations lately due to their wide applications in important technological fields such as bioimaging probes, bioconjucation, second generation photosensitizers for photodynamic therapy, second harmonic generating organic dyes, two-photon absorbing materials with large cross section values, and, finally, photoconducting materials in photovoltaic cells. While a large number of patents and papers has been produced regarding their applications limited work has been done concerning their thermotropic behavior, including their liquid crystalline properties, or correlation of the crystalline structure to both the solid state aggregation and their photophysical properties. In the first chapter of this …
The Application Of Two-Photon Absorbing Probes In Lysosomal, Zinc Ion Sensing And Folate Receptor-Targeted Bioimaging, Xuhua Wang
Electronic Theses and Dissertations
Two-photon fluorescence microscopy (2PFM) has become a powerful technique for bioimaging in non-invasive cancer diagnosis and also investigating the mechanization and original of a variety of diseases by tracking various biological processes. Because the fluorescence emission by two photon absorbing (2PA) is directly proportional to the square of the intensity of excitation light, this intrinsic property of 2PA provides 2PFM great advantages over traditional one-photon fluorescence microscopy (1PFM), including high 3D spatial localization, less photodamage and interference from biological tissue because of using longer wavelength excitation (700-1300 nm). However, most 2PA probes are hydrophobic and their photostabilities are questionable, severely …
Multilayered Planar Periodic Subwavelength Microstructures For Generating And Detecting Circularly Polarized Thermal Infrared Radiation, Samuel Lanning Wadsworth
Multilayered Planar Periodic Subwavelength Microstructures For Generating And Detecting Circularly Polarized Thermal Infrared Radiation, Samuel Lanning Wadsworth
Electronic Theses and Dissertations
Generation and detection of circularly-polarized (CP) radiation in the 8- to 12-μm band of the infrared (IR) spectrum is crucial for polarization sensing and imaging scenarios. There is very little naturally occurring CP radiation in the long-wave IR band, so that useful functionalities may be obtained by exploiting preferential radiation and transmission characteristics of engineered metamaterials. Conventional CP devices in the IR utilize birefringent crystals, which are typically bulky and expensive to manufacture. The operation of these devices is generally optimized at a single wavelength. Imaging in the long-wave IR is most often broadband, so that achromatic CP-device behavior is …
Fine-Scale Structures In Saturn's Rings Waves, Wakes And Ghosts, Kevin Baille
Fine-Scale Structures In Saturn's Rings Waves, Wakes And Ghosts, Kevin Baille
Electronic Theses and Dissertations
The Cassini mission provided wonderful tools to explore Saturn, its satellites and its rings system. The UVIS instrument allowed stellar occultation observations of structures in the rings with the best resolution available (around 10 meters depending on geometry and navigation), bringing our understanding of the physics of the rings to the next level. In particular, we have been able to observe, dissect, model and test the interactions between the satellites and the rings. We first looked at kilometer-wide structures generated by resonances with satellites orbiting outside the main rings. The observation of structures in the C ring and their association …
Iteratively Reweighted Least Squares Minimization With Prior Information A New Approach, Dmitriy Popov
Iteratively Reweighted Least Squares Minimization With Prior Information A New Approach, Dmitriy Popov
Electronic Theses and Dissertations
Iteratively reweighted least squares (IRLS) algorithms provide an alternative to the more standard 1 l -minimization approach in compressive sensing. Daubechies et al. introduced a particularly stable version of an IRLS algorithm and rigorously proved its convergence in 2010. They did not, however, consider the case in which prior information on the support of the sparse domain of the solution is available. In 2009, Miosso et al. proposed an IRLS algorithm that makes use of this information to further reduce the number of measurements required to recover the solution with specified accuracy. Although Miosso et al. obtained a number of …
Virtual Router Approach For Wireless Ad Hoc Networks, Ai Hua Ho
Virtual Router Approach For Wireless Ad Hoc Networks, Ai Hua Ho
Electronic Theses and Dissertations
Wireless networks have become increasingly popular in recent years. There are two variations of mobile wireless networks: infrastructure mobile networks and infrastructureless mobile networks. The latter are also known as mobile ad hoc network (MANET). MANETs have no fixed routers. Instead, mobile nodes function as relay nodes or routers, which discover and maintain communication connections between source nodes and destination nodes for various data transmission sessions. In other words, an MANET is a self-organizing multi-hop wireless network in which all nodes within a given geographical area participate in the routing and data forwarding process. Such networks are scalable and self-healing. …
Analytic & Numerical Study Of A Vortex Motion Equation, Daniel Bueller
Analytic & Numerical Study Of A Vortex Motion Equation, Daniel Bueller
Electronic Theses and Dissertations
A nonlinear second order differential equation related to vortex motion is derived. This equation is analyzed using various numerical and analytical techniques including finding approximate solutions using a perturbative approach.
Intracavity Laser Absorption Spectroscopy Using Quantum Cascade Laser And Fabry-Perot Interferometer, Gautam Medhi
Intracavity Laser Absorption Spectroscopy Using Quantum Cascade Laser And Fabry-Perot Interferometer, Gautam Medhi
Electronic Theses and Dissertations
Intracavity Laser Absorption Spectroscopy (ICLAS) at IR wavelengths offers an opportunity for spectral sensing of low vapor pressure compounds. We report here an ICLAS system design based on a quantum cascade laser (QCL) at THz (69.9 m) and IR wavelengths (9.38 and 8.1 m) with an open external cavity. The sensitivity of such a system is potentially very high due to extraordinarily long effective optical paths that can be achieved in an active cavity. Sensitivity estimation by numerical solution of the laser rate equations for the THz QCL ICLAS system is determined. Experimental development of the external cavity QCL is …
Electromagnetic Propagation Anomalies In Waveguiding Structures And Scattering Systems, Alessandro Salandrino
Electromagnetic Propagation Anomalies In Waveguiding Structures And Scattering Systems, Alessandro Salandrino
Electronic Theses and Dissertations
The effects related to diffraction and interference are ubiquitous in phenomena involving electromagnetic wave propagation, and are accurately predicted and described within the framework of classical electrodynamics. In the vast majority of the cases the qualitative features of the evolution of a propagating wave can be inferred even without detailed calculations. A field distribution will spread upon propagation, will accumulate phase along the direction of power flow, will exert mechanical forces upon scattering objects in the direction of propagation etc. When such predictions fail, counterintuitive effects and new functionalities can be engineered. In this work a series of exceptional cases …
Photo Retro Diels-Alder Reaction Of The Adducts Of Tetracyanoethylene And Polyaromatic Compounds, Siddthartha Banerjee
Photo Retro Diels-Alder Reaction Of The Adducts Of Tetracyanoethylene And Polyaromatic Compounds, Siddthartha Banerjee
Electronic Theses and Dissertations
Thermally induced retro-Diels Alder (rDA) reaction has been extensively used for the preparation of many reactive intermediates in organic synthesis. But the uses of photo-retro Diels-Alder (PrDA) reaction in organic synthesis were sparingly reported in literature. Due to its spatial and temporal control, PrDA can be used in making of photosensitive materials, in drug delivery and also for mechanistic studies. Diels-Alder adducts of tetracyanoethylene (TCNE) and polyaromatic compounds (anthracene, napthacene, pentacene and phencyclone) were synthesized and were subjected to PrDA reaction through 254-nm irradiation. The quantum yield and the consequent photoreactivity of these DA adducts follow the following order. TCNE/naphthacene …
The Study Of Three Different Layered Structures As Model Systems For Hydrogen Storage Materials, Muzaffer Tonguç Öztek
The Study Of Three Different Layered Structures As Model Systems For Hydrogen Storage Materials, Muzaffer Tonguç Öztek
Electronic Theses and Dissertations
The strength and success of the hydrogen economy relies heavily on the storage of hydrogen. Storage systems in which hydrogen is sequestered in a solid material have been shown to be advantageous over storage of hydrogen as a liquid or compressed gas. Many different types of materials have been investigated, yet the desired capacity and uptake/release characteristics required for implementation have not been reached. In this work, porphyrin aggregates were investigated as a new type of material for hydrogen storage. The building blocks of the aggregates are porphyrin molecules that are planar and can assume a face to face arrangement …
An Evaluation Study Of The Effectiveness Of Using A Reaction-Based Process For Hydrazine Waste Remediation, Cristina M. Oropeza
An Evaluation Study Of The Effectiveness Of Using A Reaction-Based Process For Hydrazine Waste Remediation, Cristina M. Oropeza
Electronic Theses and Dissertations
Hydrazine (HZ) and monomethylhydrazine (MMH) are used extensively as hypergolic propellants at Kennedy Space Center. These highly reactive fuels are considered highly toxic, and potentially carcinogenic. Consequently, the transport, handling, and disposal of hydrazines is strictly regulated to protect personnel and the environment. Currently, KSC generates large volumes of hydrazine-laden wastewater for disposal. This waste is contained and shipped on public highways for subsequent disposal by incineration presenting a potentially catastrophic threat to the environment and the general public in the event of an accidental release. Other existing remediation methods include oxidative and reductive pathways as well as biodegradation in …
Computationally Efficient Digital Backward Propagation For Fiber Nonlinearity Compensation, Likai Zhu
Computationally Efficient Digital Backward Propagation For Fiber Nonlinearity Compensation, Likai Zhu
Electronic Theses and Dissertations
The next generation fiber transmission system is limited by fiber nonlinearity. A distributed nonlinearity compensation method, known as Digital Backward Propagation (DBP), is necessary for effective compensation of the joint effect of dispersion and nonlinearity. However, in order for DBP to be accurate, a large number of steps are usually required for long-haul transmission, resulting in a heavy computational load. In real time DBP implementation, the FIR filters can be used for dispersion compensation and account for most of the computation per step. A method of designing a complementary filter pair is proposed. The individual errors in the frequency response …
Finding Dud Vertices In Defensive Alliances And Secure Sets Using Computational Tools, George Worley Ii
Finding Dud Vertices In Defensive Alliances And Secure Sets Using Computational Tools, George Worley Ii
Electronic Theses and Dissertations
Defensive alliances are a way of using graphs to model the defense of resources (people, buildings, countries, etc.) against attacks where the number of potential attackers against each resource is known. The initial study of defensive alliances focused on questions of minimal defensive alliances in a graph and the minimum possible size of a defensive alliance in a graph, but in order to apply defensive alliances in modeling real-world situations, additional considerations are important. In particular, since each vertex in a defensive alliance represents some real-world object that has a cost associated with remaining in the defensive alliance, it is …
The Power Of Quantum Walk Insights, Implementation, And Applications, Chen Fu Chiang
The Power Of Quantum Walk Insights, Implementation, And Applications, Chen Fu Chiang
Electronic Theses and Dissertations
In this thesis, I investigate quantum walks in quantum computing from three aspects: the insights, the implementation, and the applications. Quantum walks are the quantum analogue of classical random walks. For the insights of quantum walks, I list and explain the required components for quantizing a classical random walk into a quantum walk. The components are, for instance, Markov chains, quantum phase estimation, and quantum spectrum theorem. I then demonstrate how the product of two reflections in the walk operator provides a quadratic speed-up, in comparison to the classical counterpart. For the implementation of quantum walks, I show the construction …
Exploring Confidence Intervals In The Case Of Binomial And Hypergeometric Distributions, Irene Mojica
Exploring Confidence Intervals In The Case Of Binomial And Hypergeometric Distributions, Irene Mojica
Electronic Theses and Dissertations
The objective of this thesis is to examine one of the most fundamental and yet important methodologies used in statistical practice, interval estimation of the probability of success in a binomial distribution. The textbook confidence interval for this problem is known as the Wald interval as it comes from the Wald large sample test for the binomial case. It is generally acknowledged that the actual coverage probability of the standard interval is poor for values of p near 0 or 1. Moreover, recently it has been documented that the coverage properties of the standard interval can be inconsistent even if …
Investigation Of Nanoceria-Modified Platinum-Gold Composite Electrodes For The Electrochemical Reduction Of Oxygen In Alkaline Media, Rahul Hegishte
Investigation Of Nanoceria-Modified Platinum-Gold Composite Electrodes For The Electrochemical Reduction Of Oxygen In Alkaline Media, Rahul Hegishte
Electronic Theses and Dissertations
Platinum-gold and nanoceria-modified platinum-gold electrodes were prepared on a platinum surface via electrochemical reduction of solutions of platinum and gold salts in the dispersion of nanoceria. The molar ratios of Pt and Au were varied in both PtAu and PtAu/CeO₂ electrodes while the total concentration of the metals was maintained at 2 x 10⁻³M and the concentration of nanoceria was maintained constant at 5 x 10⁻³M. The electrodes were characterized by their cyclic voltammetry curves in 0.5M sulfuric acid solution. The electrochemically active area of the electrodes was determined using the copper underpotential deposition method. The linear sweep voltammograms of …
Metal Blacks As Scattering Centers To Increase The Efficiency Of Thin Film Solar Cells, Deep R. Panjwani
Metal Blacks As Scattering Centers To Increase The Efficiency Of Thin Film Solar Cells, Deep R. Panjwani
Electronic Theses and Dissertations
Metal nano particles are investigated as scattering centers on front surface of thin-film solar cells to improve efficiency. The principle is that scattering, which is enhanced near the plasmon resonance frequency of the particle and depends on particle size, increases the effective optical path length of incident light, leading to more light absorption in active layer of thin film solar cell. The particular types of particles investigated here are known as "metal-black", well known as an IR absorber for bolometric infrared detectors. Gold-black was deposited on commercial thin-film solar cells using a thermal evaporator in a nitrogen ambient at pressures …
Research In High Performance And Low Power Computer Systems For Data-Intensive Environment, Pengju Shang
Research In High Performance And Low Power Computer Systems For Data-Intensive Environment, Pengju Shang
Electronic Theses and Dissertations
According to the data affinity, DAFA re-organizes data to maximize the parallelism of the affinitive data, and also subjective to the overall load balance. This enables DAFA to realize the maximum number of map tasks with data-locality. Besides the system performance, power consumption is another important concern of current computer systems. In the U.S. alone, the energy used by servers which could be saved comes to 3.17 million tons of carbon dioxide, or 580,678 cars {Kar09}. However, the goals of high performance and low energy consumption are at odds with each other. An ideal power management strategy should be able …
Low Noise, Narrow Optical Linewidth Semiconductor-Based Optical Comb Source And Low Noise Rf Signal Generation, Ibrahim Tuna Ozdur
Low Noise, Narrow Optical Linewidth Semiconductor-Based Optical Comb Source And Low Noise Rf Signal Generation, Ibrahim Tuna Ozdur
Electronic Theses and Dissertations
Recently optical frequency combs and low noise RF tones are drawing increased attention due to applications in spectroscopy, metrology, arbitrary waveform generation, optical signal processing etc. This thesis focuses on the generation of low noise RF tones and stabilized optical frequency combs. The optical frequency combs are generated by a semiconductor based external cavity mode-locked laser with a high finesse intracavity etalon. In order to get the lowest noise and broadest bandwidth from the mode-locked laser, it is critical to know the free spectral range (FSR) of the etalon precisely. First the etalon FSR is measured by using the modified …
The Relative Recoverability Of Dna And Rna Profiles From Forensically Relevant Body Fluid Stains, Charly Parker
The Relative Recoverability Of Dna And Rna Profiles From Forensically Relevant Body Fluid Stains, Charly Parker
Electronic Theses and Dissertations
Biological material (fluids or tissues) whether from the victim or suspect is often collected as forensic evidence, and methods to obtain and analyze the DNA found in that material have been well established. The type of body fluid (i.e. blood, saliva, semen, vaginal secretions, and menstrual blood) from which the DNA originated is also of interest, and messenger RNA typing provides a specific and sensitive means of body fluid identification. In order for mRNA profiling to be utilized in routine forensic casework, RNA of sufficient quantity and quality must be obtained from biological fluid stains and the methods used for …
Infrared Phased-Array Antenna-Coupled Tunnel Diodes, Brian Alan Slovick
Infrared Phased-Array Antenna-Coupled Tunnel Diodes, Brian Alan Slovick
Electronic Theses and Dissertations
Infrared (IR) dipole antenna-coupled metal-oxide-metal (MOM) tunnel diodes provide a unique detection mechanism that allows for determination of the polarization and wavelength of an optical field. By integrating the MOM diode into a phased-array antenna, the angle of arrival and degree of coherence of received IR radiation can be determined. The angular response characteristics of IR dipole antennas are determined by boundary conditions imposed by the surrounding dielectric or conductive environment on the radiated fields. To explore the influence of the substrate configuration, single dipole antennas are fabricated on both planar and hemispherical lens substrates. Measurements demonstrate that the angular …
Low Noise And Low Repetition Rate Semiconductor-Based Mode-Locked Lasers, Dimitrios Mandridis
Low Noise And Low Repetition Rate Semiconductor-Based Mode-Locked Lasers, Dimitrios Mandridis
Electronic Theses and Dissertations
The topic of this dissertation is the development of low repetition rate and low noise semiconductor-based laser sources with a focus on linearly chirped pulse laser sources. In the past decade chirped optical pulses have found a plethora of applications such as photonic analogto-digital conversion, optical coherence tomography, laser ranging, etc. This dissertation analyzes the aforementioned applications of linearly chirped pulses and their technical requirements, as well as the performance of previously demonstrated chirped pulse laser sources. Moreover, the focus is shifted to a specific application of the linearly chirped pulses, timestretched photonic analog-to-digital conversion (TS ADC). The challenges of …
Ray Collection Bounding Volume Hierarchy, Kris Krishna Rivera
Ray Collection Bounding Volume Hierarchy, Kris Krishna Rivera
Electronic Theses and Dissertations
This thesis presents Ray Collection BVH, an improvement over a current day Ray Tracing acceleration structure to both build and perform the steps necessary to efficiently render dynamic scenes. Bounding Volume Hierarchy (BVH) is a commonly used acceleration structure, which aides in rendering complex scenes in 3D space using Ray Tracing by breaking the scene of triangles into a simple hierarchical structure. The algorithm this thesis explores was developed in an attempt at accelerating the process of both constructing this structure, and also using it to render these complex scenes more efficiently. The idea of using "ray collection" as a …
Convergence Of The Mean Shift Algorithm And Its Generalizations, Ting Hu
Convergence Of The Mean Shift Algorithm And Its Generalizations, Ting Hu
Electronic Theses and Dissertations
Mean shift is an effective iterative algorithm widely used in image analysis tasks like tracking, image segmentation, smoothing, filtering, edge detection and etc. It iteratively estimates the modes of the probability function of a set of sample data points based in a region. Mean shift was invented in 1975, but it was not widely used until the work by Cheng in 1995. After that, it becomes popular in computer vision. However the convergence, a key character of any iterative algorithm, has been rigorously proved only very recently, but with strong assumptions. In this thesis, the method of mean shift is …
Bayesian Model Selection For Classification With Possibly Large Number Of Groups, Justin Kyle Davis
Bayesian Model Selection For Classification With Possibly Large Number Of Groups, Justin Kyle Davis
Electronic Theses and Dissertations
The purpose of the present dissertation is to study model selection techniques which are specifically designed for classification of high-dimensional data with a large number of classes. To the best of our knowledge, this problem has never been studied in depth previously. We assume that the number of components p is much larger than the number of samples n, and that only few of those p components are useful for subsequent classification. In what follows, we introduce two Bayesian models which use two different approaches to the problem: one which discards components which have “almost constant” values (Model 1) and …
Variational Embedded Solitons, And Traveling Wavetrains Generated By Generalized Hopf Bifurcations, In Some Nlpde Systems, Todd Blanton Smith
Variational Embedded Solitons, And Traveling Wavetrains Generated By Generalized Hopf Bifurcations, In Some Nlpde Systems, Todd Blanton Smith
Electronic Theses and Dissertations
In this Ph.D. thesis, we study regular and embedded solitons and generalized and degenerate Hopf bifurcations. These two areas of work are seperate and independent from each other. First, variational methods are employed to generate families of both regular and embedded solitary wave solutions for a generalized Pochhammer PDE and a generalized microstructure PDE that are currently of great interest. The technique for obtaining the embedded solitons incorporates several recent generalizations of the usual variational technique and is thus topical in itself. One unusual feature of the solitary waves derived here is that we are able to obtain them in …