Physical Sciences and Mathematics Commons^™

Experiments In Graphene And Plasmonics, Christian Smith

Electronic Theses and Dissertations

Graphene nanoribbons, graphene based optical sensors, and grating based plasmonics are explored experimentally. Graphene nanoribbons exhibit highly insulating states that may allow for graphene based digital applications. We investigate the sensitivity of these states to local charged impurities in ultra high vacuum. We look into the possibility of isolating two-dimensional films of H-BN and BSCCO, and test for any interesting phenomena. We also assess graphene*s applicability for optical sensing by implementing a new style of spectral detector. Utilizing surface plasmon excitations nearby a graphene field-effect transistor we are able to produce a detector with wavelength sensitivity and selectivity in the …

Entangled Photon Pairs In Disordered Photonic Lattices, Lane Martin

Electronic Theses and Dissertations

Photonic lattices consisting of arrays of evanescently coupled waveguides fabricated with precisely controlled parameters have enabled the study of discrete optical phenomena, both classical and quantum, and the simulation of other physical phenomena governed by the same dynamics. In this dissertation, I have experimentally demonstrated transverse Anderson localization of classical light in arrays with off-diagonal coupling disorder and investigated theoretically and experimentally the propagation of entangled photon pairs through such disordered systems. I discovered a new phenomenon, Anderson co-localization, in which a spatially entangled photon pair in a correlated transversally extended state localizes in the correlation space, though neither photon …

Holographic Recording And Applications Of Multiplexed Volume Bragg Gratings In Photo-Thermo-Refractive Glass, Daniel Ott

Electronic Theses and Dissertations

Recent developments in holographic recording of volume Bragg gratings (VBGs) in photo-thermo-refractive (PTR) glass have demonstrated their utility as components in high power laser systems for spectral narrowing, transverse mode control, beam combining, and pulse stretching/compression. VBG structures are capable of diffracting incident light into a single diffraction order with high efficiency given the Bragg condition is met. The Bragg condition depends on both the wavelength and angle of the incident light making VBGs useful for filtering and manipulating both the wavelength and angular spectrum of a source. This dissertation expands upon previous research in PTR VBGs by investigating multiplexed …

Nonlinear Integrated Photonics On Silicon And Gallium Arsenide Substrates, Jichi Ma

Electronic Theses and Dissertations

Silicon photonics is nowadays a mature technology and is on the verge of becoming a blossoming industry. Silicon photonics has also been pursued as a platform for integrated nonlinear optics based on Raman and Kerr effects. In recent years, more futuristic directions have been pursued by various groups. For instance, the realm of silicon photonics has been expanded beyond the well-established near-infrared wavelengths and into the mid-infrared (3 - 5 µm). In this wavelength range, the omnipresent hurdle of nonlinear silicon photonics in the telecommunication band, i.e., nonlinear losses due to two-photon absorption, is inherently nonexistent. With the lack of …

The Role Of Ugandan Women In Rural Agriculture And Food Security, Karen Ann Mckenna

Electronic Theses and Dissertations

Women engaged in small-scale rural agriculture in Iganga, Uganda for the purpose of household food security and/or income generation face a number of challenges to creating sustainable livelihoods. This analysis is presented in the form of a case study based on research conducted over the period of one year in Uganda between September 2012 and September 2013. Three conceptual orientations are used to guide the research, including sustainable livelihoods, gender and agricultural development, and food security. Pertinent economic, political, and social contexts are identified for each of these orientations. The author then identifies key challenges that women in Iganga face …

Probing Structure For Photophysical Properties Through Synthesis Of Novel Nucleosides, Brittney Jean Rodgers

Electronic Theses and Dissertations

A brief history of nucleosides and their photophysics provides the background information for the discussion of synthesis, photophysics and incorporation of fluorescent nucleotide analogs during enzymatic DNA synthesis. Through the use of nucleoside starting material, it is possible to synthesize a number of modified nucleotides for use as fluorescent probes in biochemical research. Synthetic endeavors into the synthesis of these and related molecules from nucleobase starting materials are also presented. The synthesis of these molecules involved re-development of the synthetic routes to broaden substrate scope by overcoming the changed reactivity resulting from the presence of additional functionality.

While many highly …

Topological Ramsey Spaces, Associated Ultrafilters, And Their Applications To The Tukey Theory Of Ultrafilters And Dedekind Cuts Of Nonstandard Arithmetic, Timothy Onofre Trujillo

Electronic Theses and Dissertations

This dissertation makes contributions to the areas of combinatorial set theory, the model theory of arithmetic, and the Tukey theory of ultrafilters. The main results are broken into three parts.

In the first part, we identify some new partition relations among finite trees and use them to answer an open question of Dobrinen; namely, "for n < omega, are the notions of Ramsey for Rn and selective for Rn equivalent?" We show that for each n < omega, it is consistent with ZFC that there exists a selective for Rn ultrafilter which is not Ramsey for Rn.

In the second part, we extend results of Blass concerning Dedekind cuts associated to ultrafilter mappings from p-point and weakly-Ramsey ultrafilters to ultrafilter mappings from Ramsey for R1 ultrafilters. Blass associates to each ultrafilter U on a countable set X and each function g …

An Empirical Comparison Of Reuse In Embedded And Nonembedded Systems, Julia F. Varnell-Sarjeant

Electronic Theses and Dissertations

High-quality software, delivered on time and budget, constitutes a critical part of most products and services in modern society. Our government has invested billions of dollars to develop software assets, often to redevelop the same capability many times. Recognizing the waste involved in redeveloping these assets, in 1992 the Department of Defense issued the Software Reuse Initiative.

The vision of the Software Reuse Initiative was "To drive the DoD software community from its current "re-invent the software" cycle to a process-driven, domain-specific, architecture-centric, library-based way of constructing software.'' Twenty years after issuing this initiative, there is evidence of this vision …

Structure Vs. Properties Using Chemical Graph Theory, Tabitha N. Williford

Electronic Theses and Dissertations

Chemical graph theory began as a way for mathematicians to bring together the areas of the Physical Sciences and Mathematics. Through its use, mathematicians are able to model chemical systems, predict their properties as well as structure-property relationships. In this dissertation, we consider two questions involving chemical graph theory and its applications. We first look at tree-like polyphenyl systems, which form an important family of compounds in Chemistry, particularly in Material Science. The importance can be seen in LEDs, transmitters, and electronics. In recent years, many extremal results regarding such systems under specific constraints have been reported. More specifically are …

Degradation Of High Voltage Glass Fiber-Reinforced Polymer Matrix Composites By Aggressive Environmental Conditions, Tianyi Lu

Electronic Theses and Dissertations

Polymer matrix composites reinforced with either E glass or ECR glass fibers-reinforced are used in a variety of high voltage electrical applications because of their advantages like lower weight and cost. However, they can be damaged by aggressive in-service conditions such as high temperature, ultraviolet radiation, moisture, ozone and corrosive environments. Different degradation mechanisms can develop in high voltage PMCs under those extreme environments, which, in turn, can affect the long term structural durability of the composites. A set of PMCs reinforced with ECR-glass and E-glass fibers embedded in four different resins has been investigated in this study. In addition, …

Noncovalent Interactions Involving Microsolvated Networks Of Trimethylamine N-Oxide, Kristina Andrea Cuellar

Electronic Theses and Dissertations

This thesis research focuses on the effects of the formation of hydrogen-bonded networks with the important osmolyte trimethylamine N-oxide (TMAO). Vibrational spectroscopy, in this case Raman spectroscopy, is used to interpret the effects of noncovalent interactions by solvation with select hydrogen bond donors such as water, methanol, ethanol and ethylene glycol in the form of slight changes in vibrational frequencies. Spectral shifts in the experimental Raman spectra of interacting molecules are compared to the results of electronic structure calculations on explicit hydrogen bonded molecular clusters. The similarities in the Raman spectra of microsolvated TMAO using a variety of hydrogen bond …

Moments Of Products Of L-Functions, Caroline Laroche Turnage-Butterbaugh

Electronic Theses and Dissertations

We first consider questions on the distribution of the primes. Using the recent advancement towards the Prime k-tuple Conjecture by Maynard and Tao, we show how to produce infinitely many strings of consecutive primes satisfying specified congruence conditions. We answer an old question of Erdös and Turán by producing strings of consecutive primes whose successive gaps form an increasing (respectively decreasing) sequence. We also show that such strings exist whose successive gaps follow a certain divisibility pattern. Finally, for any coprime integers a and D ≥ 1, we refine a theorem of D. Shiu and find strings of consecutive primes …

(Visible) Tilings Of Squares And Hypercubes, John Randall Burt

Electronic Theses and Dissertations

More than eighty years ago, Erdos considered sums of the side lengths of squares packed into a unit square.Here we consider various classes of tilings , this is, packings where there is no empty space inside the unit square. Several types of questions will be explored here. Various construction techniques are introduced, especially methods of generating tilings from tilings with fewer tiles. For some small values of n, I determine all tilings of the unit square with n tiles. I have found a best possible upper bound for a visible tiling, that is a tiling which every tile shares a …

Comparing K Population Means With No Assumption About The Variances, Tony Yaacoub

Electronic Theses and Dissertations

In the analysis of most statistically designed experiments, it is common to assume equal variances along with the assumptions that the sample measurements are independent and normally distributed. Under these three assumptions, a likelihood ratio test is used to test for the difference in population means. Typically, the assumption of independence can be justified based on the sampling method used by the researcher. The likelihood ratio test is robust to the assumption of normality. However, the equality of variances is often difficult to justify. It has been found that the assumption of equal variances cannot be made even after transforming …

Elements Of Convergence Approach Theory, William D. Trott

Electronic Theses and Dissertations

We introduce two generalizations to convergence approach spaces of classical results characterizing regularity of a convergence space in terms of continuous extensions of maps on one hand, and in terms of continuity of limits for the continuous convergence on the other. Characterizations are obtained for two alternative extensions of reg- ularity to convergence-approach spaces: regularity and strong regularity. Along the way, we give a brief overview of the theory of convergence spaces and of convergence approach spaces.

Polymorphic Data Modeling, Steven R. Benson

Electronic Theses and Dissertations

There are currently no data modeling standards for modeling NoSQL document store databases. This work proposes a standard to fill the void. The proposed standard is based on our new data modeling pattern named The Polymorphic Table Pattern. The pattern embraces the “schemaless” nature of document store NoSQL while allowing the data modeler to use his or her existing skillsets. The concepts of our proposed modeling have been demonstrated against MongoDB.

Statistical Analysis Of Unreplicated Factorial Designs Using Contrasts, Meixi Yang

Electronic Theses and Dissertations

Factorial designs can have a large number of treatments due to the number of factors and the number of levels of each factor. The number of experimental units required for a researcher to conduct a $k$ factorial experiment is at least the number of treatments. For such an experiment, the total number of experimental units will also depend on the number of replicates for each treatment. The more experimental units used in a study the more the cost to the researcher. The minimum cost is associated with the case in which there is one experimental unit per treatment. That is, …

Synthesis, Characterization And Electrochemical Properties Of Gold Nanomolecules, Vijay Bhaskar Reddy Jupally

Electronic Theses and Dissertations

Chapter 1 gives a brief introduction to the field of gold nanomolecules. Various synthetic protocols and analytical techniques used through out this dissertation are discussed in detail. Size dependent properties of the gold nanomolecules are described. The structure of gold nanomolecules is explained based on the crystal structure of Au25(SCH2CH2Ph)18. The theoretical basis for the stability of the gold nanomolecules is explained using the super atom complex model and geometric parameters. Chapter 2 includes ligand exchange experiments on gold nanomolecules. Ligand exchange experiments are used to modify the monolayer of nanomolecules after synthesis. Ligand exchange reactions are monitored by mass …

Applications Of Epr With An Emphasis On Tau Fibril Structure, Virginia Meyer

Electronic Theses and Dissertations

Substances containing unpaired electrons have been studied by electron paramagnetic resonance (EPR) for nearly 70 years. With continual development and enhancement of EPR techniques, questions have arisen regarding optimum method selection for a given sample based on its properties. In this work, radiation defects, natural lattice defects, solid organic radicals, radicals in solution, and spin-labeled proteins were analyzed using CW, pulse, and rapid scan EPR to compare methods. Studies of solid BDPA, E' in quartz, N_s⁰ in diamond, and a-Si:H, showed that rapid scan could overcome many obstacles presented by other techniques, cementing rapid scan as an effective …

Nanoscale Thermoelectrics: A Study Of The Absolute Seebeck Coefficient Of Thin Films, Sarah J. Mason

Electronic Theses and Dissertations

The worlds demand for energy is ever increasing. Likewise, the environmental impact of climate change due generating that energy through combustion of fossil fuels is increasingly alarming. Due to these factors new sources of renewable energies are constantly being sought out. Thermoelectric devices have the ability to generate clean, renewable, energy out of waste heat. However promising that is, their inefficiency severely inhibits applicability and practical use. The usefulness of a thermoelectric material increases with the dimensionless quantity, ZT, where, Z = S²σ/κ, and S, σ, and κ are the Seebeck coefficient and electrical and thermal …

Emplacement Of Pleistocene Basalt Flows Near Mccoy, Colorado, Andrea Bowen

Electronic Theses and Dissertations

No abstract provided.

Ramsey Theory Using Matroid Minors, Dixie Smith Horne

Electronic Theses and Dissertations

This thesis considers a Ramsey Theory question for graphs and regular matroids. Specifically, how many elements N are required in a 3-connected graphic or regular matroid to force the existence of certain specified minors in that matroid? This question cannot be answered for an arbitrary collection of specified minors. However, there are results from the literature for which the number N exists for certain collections of minors. We first encode totally unimodular matrix representations of certain matroids. We use the computer program MACEK to investigate this question for certain classes of specified minors.

Nano-Pipette As Nanoparticle Analyzer And Capillary Gated Ion Transistor, Yauheni Rudzevich

Electronic Theses and Dissertations

The ability to precisely count inorganic and organic nanoparticles and to measure their size distribution plays a major role in various applications such as drug delivery, nanoparticles counting, and many others. In this work I present a simple resistive pulse method that allows translocations, counting, and measuring the size and velocity distribution of silica nanoparticles and liposomes with diameters from 50 nm to 250 nm. This technique is based on the Coulter counter technique, but has nanometer size pores. It was found that ionic current drops when nanoparticles enter the nanopore of a pulled micropipette, producing a clear translocation signal. …

Complementary Layered Learning, Sean Mondesire

Electronic Theses and Dissertations

Layered learning is a machine learning paradigm used to develop autonomous robotic-based agents by decomposing a complex task into simpler subtasks and learns each sequentially. Although the paradigm continues to have success in multiple domains, performance can be unexpectedly unsatisfactory. Using Boolean-logic problems and autonomous agent navigation, we show poor performance is due to the learner forgetting how to perform earlier learned subtasks too quickly (favoring plasticity) or having difficulty learning new things (favoring stability). We demonstrate that this imbalance can hinder learning so that task performance is no better than that of a suboptimal learning technique, monolithic learning, which …

Comparison Of Casimir , Elastic, Electrostatic Forces For A Micro-Cantilever, Ammar Alhasan

Electronic Theses and Dissertations

Casimir force is a cause of stiction (adhesion) between metal surfaces in Micro-Electro Mechanical Systems (MEMS). Casimir Force depends strongly on the separation of the two surfaces and the contact area. This thesis reviews the theory and prior experimental demonstrations of the Casimir force. Then the Casimir attractive force is calculated for a particular MEMS cantilever device, in which the metal cantilever tip is required to repeatedly touch and release from a metal tip pad on the substrate surface in response to a periodic driving electrostatic force. The elastic force due to the bending of the cantilever support arms is …

Exploring Sparsity, Self-Similarity, And Low Rank Approximation In Action Recognition, Motion Retrieval, And Action Spotting, Chuan Sun

Electronic Theses and Dissertations

This thesis consists of 4 major parts. In the first part (Chapters 1-2), we introduce the overview, motivation, and contribution of our works, and extensively survey the current literature for 6 related topics. In the second part (Chapters 3-7), we explore the concept of "Self-Similarity" in two challenging scenarios, namely, the Action Recognition and the Motion Retrieval. We build three-dimensional volume representations for both scenarios, and devise effective techniques that can produce compact representations encoding the internal dynamics of data. In the third part (Chapter 8), we explore the challenging action spotting problem, and propose a feature-independent unsupervised framework that …

Pen-Based Methods For Recognition And Animation Of Handwritten Physics Solutions, Salman Cheema

Electronic Theses and Dissertations

There has been considerable interest in constructing pen-based intelligent tutoring systems due to the natural interaction metaphor and low cognitive load afforded by pen-based interaction. We believe that pen-based intelligent tutoring systems can be further enhanced by integrating animation techniques. In this work, we explore methods for recognizing and animating sketched physics diagrams. Our methodologies enable an Intelligent Tutoring System (ITS) to understand the scenario and requirements posed by a given problem statement and to couple this knowledge with a computational model of the student's handwritten solution. These pieces of information are used to construct meaningful animations and feedback mechanisms …

Zinc Sulfide: Manganese Doped Quantum Rods For Detection Of Metal Ions And A Business Model For Future Sales, Andrew Teblum

Electronic Theses and Dissertations

Hexavalent chromium is an extremely carcinogenic chemical that has been widely produced in the United States. This has led to major waste contamination and pollution throughout the country. According to the Environmental Working Group Hexavalent chromium has been found in 89% of city tap water. Most people believe they are safe using regular home filter systems however that is not true. A more expensive ion exchange water treatment unit is required. Therefore to protect yourselves from this carcinogenic metal a reliable test is required. In this study we have developed a Zinc Sulfide Manganese doped Quantum Rod technology to detect …

Multimaterial Fibers In Photonics And Nanotechnology, Guangming Tao

Electronic Theses and Dissertations

Recent progress in combing multiple materials with distinct optical, electronic, and thermomechanical properties monolithically in a kilometer-long fiber drawn from a preform offers unique multifunctionality at a low cost. A wide range of unique in-fiber devices have been developed in fiber form-factor using this strategy. Here, I summary my recent results in this nascent field of 'multimaterial fibers'. I will focus on my achievements in producing robust infrared optical fibers and in appropriating optical fiber production technology for applications in nanofabrication. The development of optical components suitable for the infrared (IR) is crucial for applications in this spectral range to …

The Development And Application Of A Larval Pallid Sturgeon (Scaphirhynchus Albus) Bioenergetics Model, Laura B. Heironimus

Electronic Theses and Dissertations

Pallid Sturgeon Scaphirhynchus albus are native fish of the Missouri and lower Mississippi River basins and currently listed as an endangered species under the Federal Endangered Species Act. As a result of anthropogenic alterations within the Missouri River, including dredging, channelization, and construction of large reservoirs, Pallid Sturgeon reproduction is reduced or eliminated throughout the species range. Due to a lack of wild progeny, little is known of the larval Pallid Sturgeon and their habitat or environmental requirements. To increase knowledge on the larval Pallid Sturgeon’s physiological requirements for growth and survival, the objective of this study was to develop …